HomeMy WebLinkAboutR-2004-165 2004 Wastewater Facility Plan - Black & Veatch - FULL DOCUMENT -no hard copyI spoke with someone at the Dept of Ecology and it appears that the WWFP dated 2000 was not
finalized until 2005 In 2004 there was a draft submitted by the City to respond to comments from the
Dept of Ecology In 2005 the WWFP was finalized, however to finalize pages were replaced in the
Draft 2004 WWFP to compile a "finalized" 2005 WWFP The Final 2005 WWFP still has DRAFT in the
footer
I have attached the compiled Final 2005 WWFP including the letter between the Dept of Ecology and
the City of Yakima These copies are being sent via slingshot, if you have any trouble downloading the
documents or any questions let me know
Thank you,
Ka.tte,
KATIE PARDEE
HDR Engineering, Inc
WA Quality Coordinator
Project Coordinator
500 108th Avenue NE Suite 12001 Bellevue, WA 98004
425.450.6241
katie.pardeePhdrinc.com 1 hdrinc.com
YAKIMA REGIONAL WASTEWATER TREATMENT PLANT
2004 WASTEWATER FACILITY PLAN
AUGUST 2005
Prepared For
City of Yakima
Yakima, Washington
EXPIRES: 11/12/2005
Prepared By
k/
BLACK & VEATCH
Received 6:1 -
OCT 0 l 2004
T V
4, NEG10%,
Information Item
September 30, 2004
To: Honorable Mayor, Members of City Council, City Manager
From: Max Linden, Utility Engineer, Wastewater Division (509) 249-6814
Re: Draft 2004 Wastewater Facility Plan - Tables Clarifications
During the recent study session and public meeting regarding the Draft 2004 Wastewater facility
plan there was some confusion with the summary of recommended priority improvements for the
in the Draft 2004 Wastewater facility plan. The improvements had been divided into near term
(0-6 years), niid term (7-12 years) and long range (13-20 years) recommendations for
implementation of projects.
The number of 0-6 year priority improvements that were discussed at the study session and
public meeting were not realistic and a revised table (Work packages #2 and #3), totaling about
18 million dollars was shown to you that reflected a more realistic approach to implementing the
projects over the next 6 years. The Tables for the Priority Improvements in the Facility plan have
been revised to reflect this.
Attached with this Memo are copies of the corrected text and tables to insert into your copy of
the Draft 2004 Wastewater Facility plan. The pages they will replace are 12-14 through 12-19
and 12-23 through 12-26. If you have any additional questions please give me a call.
CITY OF YAKIMA
WASTEWATER DIVISION
2220 East Viola
Yakima, Washington 98901
Phone: 575-6077 • Fax (509) 575-6116
October 1, 2004
David Dunn, P.E.
Water Quality Program
Department of Ecology
15 West Yakima Avenue
Suite 200
Yakima, WA 98902
RE: Draft 2004 Wastewater Facility Plan
Dear Mr. Dunn:
OF Ec,
Received
OCT O 1 2004
EG
This letter is intended to provide responses to the questions and comments posed in your
September 2, 2004 letter regarding the City of Yakima's Regional Draft 2004
Wastewater Facility Plan. Thank you for reviewing and providing your comments on the
draft document. Your participation at the September 7, 2004 Public Hearing for the Draft
2004 Wastetwater Facility Plan was also appreciated. We look forward to discussing
these responses with you as necessary and fmalizing this Facility Plan to incorporate your
comments as needed.
If you have any questions please give me a call at (509) 249.-6814.
Sincerely,
Max L' den
Utility ngineer
Wastewater Division
Cc: Mayor Paul George
Yakima City Council
Dick Zais, City Manager
1
CITY OF YAKIMA
WASTEIVATER DIVISION
2220 East Viola
Yakima, Washington 98901
Phone: 575-6077 • Fax (509) 575-6116
David Dunn
Washington State Dept. Of Ecology
15 West Yakima Avenue, Suite 200
Yakima, WA 98902
Dear David Dunn,
The City of Yakima is providing the following information to you for your review and comment
as required by the National Environmental Policy Act (NEPA) and State Environmental Review
Process (SERP). The comments will be used to prepare an Environmental Information report
and the State Environmental Policy Act (SEPA) draft Environmental Checklist and Threshold
Determination for the City of Yakima's 2004 Wastewater Facility Plan. The City of Yakima
contracted with Black & Veatch Corporation to prepare a 2004 Wastewater Facility Plan that is
intended to update and supplement the Draft 2000 Wastewater Plan as required by the
Washington State Department of Ecology (WDOE). This plan describes the planning, findings,
and recommendations for the Yakima Regional Wastewater Treatment Plant (WWTP) and the
City of Yakima collection system that are necessary to maintain system reliability; to comply
with regulatory laws, rules, regulations, and requirements by federal and state governments and
agencies; and to provide adequate capacity to meet the needs of the Service Area.
Analysis of the treatment systems performed as part of this facility plan indicates the need to
provide redundancy to several operations within the treatment plant. Redundancy is required to
meet Washington State Department of Ecology criteria for provision of backup facilities to major
treatment processes to assure compliance with the City's National Pollution Discharge
Elimination Systems (NPDES) permit and associated rules and regulations. The following areas
have been identified for the 0-6 year near term planning horizon and prioritized in the planning
process as the most critical facilities requiring redundancy.
• Centrifuge Dewatering — Currently only one of the two centrifuges is functioning for
dewatering biosolids and this requires extensive maintenance to continue operating. A
new centrifuge is required to maintain compliance when the older centrifuge is out of
service.
• Solids Thickening — The waste activated sludge thickening process reduces the total
volume sent to the digestion process, and directly impacts regulatory compliance.
Currently only one dissolved air flotation thickener (DAFT) unit is in place to thicken
secondary sludge. A second thickening unit is needed to meet redundancy criteria.
• Secondary Clarification — The secondary clarifiers are the final sedimentation process
prior to discharge to the Yakima River. WDOE reliability Class I design standards
require that 75% of the design flow for this process should be handled with one unit off-
line or out of service. Based on Class I criteria, the two existing clarifiers are at or near
hydraulic capacity and an additional secondary clarifier is required for redundancy. Class Yakima
11')1
II criteria requires 50% capacity through remaining clarifiers with one out of service.
This criteria is met without an additional unit, however, the process evaluation indicated
the need for an additional clarifier to meet redundancy requirements for solids loading
conditions in the case of intermediate trickling filter clarifier failure.
• RAS /WAS Pump Station — The RAS/WAS pump station is used to transport Return
Activated Sludge (RAS) from the secondary clarifiers back to the aeration basin flow
control system through two constant speed open screw pumps. Waste activated sludge
(WAS) is pumped from the two existing secondary clarifiers through two pumping
systems. With the addition of a new secondary clarifier a new RAS/WAS pumping
station will be required. This facility will resolve existing problems with the RAS
pumping flow split and provide sufficient capacity to handle peak hour flow conditions.
• Standby Power Capacity Addition - The emergency power system supplies a backup
source of power to assure that minimum treatment is provided during a power failure.
The existing generator set was installed in 1980 and at a minimum, requires a complete
inspection/overhaul. An additional generator set is required to operate the minimum
treatment process.
• New Blowers in New Blower Building— Existing (variable frequency drives) VFDs that
operate the four 400 horsepower blowers are far less efficient and generate more
harmonic distortion on the electrical power system than newer technology. They are all
at the end of their useful life, are difficult to find replacement parts for and require
replacement. Construction of a new structure to accommodate new blowers is
recommended.
• Collection system interceptor and trunk line construction.
In addition to redundancy projects the following projects, also scheduled for the 0-6 year near
term planning horizon, have been identified as critical projects for renewal, safety and efficiency
of operations.
• Retrofit Primary Split Box — Retrofits to the primary treatment split box are needed to
improve scum removal and to allow for proper isolation of primary clarifiers.
• Replacement of Primary Clarifier Collector Mechanisms (Project 2) — Existing primary
clarifier collector mechanisms are 1936 vintage equipment that need to be replaced.
• Trickling Filter Door/Walkway Covers — Trickling filter door and walkway covers have
rusted off and should be replaced with non-metallic materials.
• Aeration Basin Diffusers Rehabilitation — The ceramic diffuser plates for basins No. 2,
No. 3, and No. 4 are 10 years old and need to be replaced with membrane fine bubble
diffusers.
• Structural Repairs to Aeration Basins 1-3 — Aeration Basins Nos. 1 — 3 are showing signs
of concrete corrosion and wear at the water surface to wall interface. Repair work similar
to what was done to Aeration Basin No. 4 is needed.
• Refurbish Secondary Clarifier Bull-Gears — Gear assemblies are over 20 years old and
due to be replaced.
• Replace Secondary Clarifier Skimmer Mechanism/Scum Box — Skimmer mechanisms
should be improved and the scum box enlarged.
• Upgrade Two Existing Secondary Clarifier Launders for Algae Control and Improved
Access — To alleviate cleaning problems of secondary clarifier launders due to algae
growth, a brush cleaning system or launder covers should be installed.
• Secondary Clarifier Spray Nozzle Installation
• Chlorination Enhancements — Improvements to the existing chlorination and
dechlorination system includes the installation of two additional chlorine scales,
modification of the chlorine contact channel baffle, and replacement of the C12 leak
detector and the SO2 residual analyzer.
• Retrofit Grit Storage Hopper — Existing grit storage hopper experiences bridging of grit
at the discharge and is deteriorating due to problems with the vibratory process that is
leading to cracks and seepage. The hopper needs to be upgraded to reduce material
bridging and extend the functional life of the equipment.
• Primary Digester Building Lighting Replacement — Due to difficulty in replacing light
bulbs at the primary digester building, improved lighting needs to be installed.
• Primary Sludge Pump Replacement — The air-diaphragm primary sludge pumps are over
25 years old and should be replaced, possibly with a different type of pumps without the
need for air compressors.
• Replacement of Secondary Scum Pumps and Piping Modification — The air-diaphragm
secondary scum pumps are over 25 years old and should be replaced. In addition, piping
modifications will provide designated suction piping and valves for pumping of
secondary scum and secondary clarifier bottom sludge.
• Replacement of Digester Gas Piping, Valves and Flow Meters — The digester gas
collection piping is over 20 years old and needs to be upsized.
• New Grease Receiving Facility.
• Enclosed Trailer and Cake Storage Facility — Because inclement weather can interfere
with dewatered cake hauling and application operations in winter, an enclosed trailer and
dewatered cake storage facility providing temporary on-site storage is necessary.
• Laboratory/Instrumentation.
• Weather Protection for Odor Control towers.
• Odor Control Improvements — Odor control for the Parshall flumes/primary clarifier
influent channels, primary clarifiers, RAS/WAS pump station, and trickling filter clarifier
effluent pump station is needed.
• Replace SCADA System — Major SCADA system components will be replaced,
including PLCs, computer hardware and software, HMI software, and historical data
logging software.
• Collection system I/I analysis and improvements.
The City of Yakima's WWTP is located at 2220 East Viola in the E1/2 of SE1/4 of Sec. 29,
R19E, T13N. The WWTP is located on the east side of I-82, 500' west of the Yakima River and
south of SR24 (Moxee Highway and bridge). The collection system is located throughout the
Urban Growth area.
Existing structures at the WWTP include: primary and secondary clarifiers, trickling filters,
aeration basins, anaerobic digesters, secondary digesters, headworks building, grit channels,
pump stations, chlorination facility, solids building, laboratory and administrative offices.
The WWTP has been constructed above the 100year floodplain. Only the outfall from the
WWTP lies within the 100 -year floodplain. There are no known environmentally sensitive areas
at the WWTP and there will be no construction activities or work performed at the outfall or with
in the 100 year floodplain. Aside from dust control issues during construction there are no known
Environmental impacts or mitigation anticipated at the WWTP. All construction to be done at
the WWTP will be done on existing WWTP property in areas of existing treatment structures
and Buildings.
All construction of Collection System transmission lines will be within the City of Yakima's
service area boundaries. The exact locations of the collection system construction activity will
not be known until further analysis is performed. Construction activities associated with the
collection system would also have possible dust control issues and there are areas designated as
sensitive areas within the Yakima Service Area. These include wetlands, groundwater recharge
areas and conservation areas. Any possible mitigation cannot be anticipated until further
assessment is provided for the collection system expansion needs.
General soil types found along the Yakima River are primarily Weirman-Naches-Ashere series,
which are well drained. To the west of the WWTP Ritzville-Warden-Starbuck series are present
that vary in depth from shallow to deep. South of the WWTP the Umapine-Esquatzel series is
present being deep and well to poorly drained.
These projects will be paid for in part by the Series B bond proceeds funding received in 2003.
Recommended improvements to the treatment facility include a variety of projects totaling an
estimated $38 million in regulatory, capacity upgrade, health and safety features and regular
renewal and replacement projects over the 20 -year planning horizon with approximately $28
million in improvements scheduled for the 0-6 year near-term capital improvement program.
Generally speaking, upgrades that are mandated by regulation are most suitable for loan and
grant financing, while smaller projects and regular renewal and replacements are most
commonly financed from available cash and rates. This does not preclude the packaging of
several related improvements into funding applications that allow similar projects to be
accomplished simultaneously. Other funding sources for loans and grants, such as State (DOE)
CCWF SRF Loans, Federal (EPA) Pre -constructions Loans and State (CTED and PWTF) loans
will be also applied for upon approval of the City of Yakima's 2004 Wastewater Facility Plan.
The City of Yakima is submitting this information as required by NEPA and SERP to solicit
your comments on important environmental and land resource issues related to the City of
Yakima's 2004 Wastewater Facility Plan. Prior to submitting a SEPA document the City of
Yakima will hold a public meeting to describe the proposed upgrades to the WWTP.
Please review our proposal and provide comments on those items of concern to your agency or
organization. If you would also like a copy of the City of Yakima's 2004 Wastewater Facility
Plan please contact Max Linden at (509) 249-6814. You will be contacted within 10 days to
verify whether or not your agency or organization will be responding to the City of Yakima's
2004 Wastewater Facility Plan.
Sincerely,
Max L
Utilit
Wa
ngineer
ater Division
Attachments: Vicinity Map with Project area identified
Photos with brief narrative
CITY OF YAKIMA •
WASTEWATER DIVISION
2220 East Viola
Yakima, Washington 98901
Phone: 575-6077 • Fax (509) 575-6116
February 27, 2004
David Dunn
Department of Ecology
Central Regional Office
15 West Yakima Avenue
Suite 200
Yakima, WA 98902-3401
Re: 2004 Wastewater Facility Plan
Dear Mr. Dunn:
Q Of EC0/00
Receivoci
FEB 2 6 2004
''Y4( REGlONQ'(((
We are pleased to transmit to you the enclosed document, 2004 Wastewater
Facility Plan, as required by permit condition S.11.A. of the City of Yakima NPDES
permit No. WA -002402-3. The plan was prepared by Black & Veatch Corporation in
accordance with WAC 173-240.
The additional requirements specified in S11.A. have been addressed in this plan
except for the documentation of the SEPA and SERP determinations, which we are in the
process of doing now. This information will be provided to you as soon as it is
completed.
The Wasteload Assessment as required by permit condition S4.F. is included in
the Facility Plan. The Schedule of Compliance -Scope of Work required in permit
condition S13.A. is included as an appendix to the Facility Plan.
We look forward to your approval and if you have any questions regarding this
document please contact Max Linden at (509) 249-6814.
Very truly yours,
U M C
Douglas Mayo P.E.
Wastewater Manager
City of Yakima
Encl: 2 copies of the City of Yakima's 2004 Wastewater Facility Plan
Yakima
M-Miuk�4Y!
1994
STATE OF WASHINGTON
DEPARTMENT OF ECOLOGY
15 West Yakima Avenue, Suite 200 • Yakima, Washington 98902-3452 • (509) 575-2490
October 26, 2005
Your address
is in the
Lower
Yakima
watershed
Max Linden
City of Yakima - Wastewater Division
2220 E. Viola
Yakima, WA 98901
RE: City of Yakima - City of Yakima 2004 Wastewater Facilities Plan
Tracking No. 0403-1B
Dear Mr. Linden:
In accordance with RCW 90.48.110 and Chapters 173-98 and 240 WAC, and on behalf of
the Department of Ecology, the Wastewater Facilities Plan dated February 2004 is hereby
approved as a facilities plan.
For the treatment plant upgrades described in this facilities plan, the Department of
Ecology has made a preliminary determination that the 0-6 year construction projects, as
proposed is 100 percent eligible for a State Water Pollution Control Revolving Fund
(SRF) loan. The estimated construction cost is $17,506,000. This determination is based
on Ecology's determination that the design flow is within the projected 20 -year eligible
design flow allowed under the SRF Program.
The Department of Ecology's financial hardship criteria established in Chapter 173-95A
WAC, "Uses and Limitations of Centennial Clean Water Fund, Chapter 173-98 WAC, Uses
and Limitations of the Water Pollution Control Revolving Fund, and the Water Quality
Program Funding Guidelines must be met by a "public body," as defined in WAC 173-
95A-020 (42) and WAC 173-98-029 (36) to be considered for grant assistance.
This preliminary determination is provided as a courtesy for financial planning, and it is
based on the current Water Quality Program Funding Guidelines (Guidelines). Future
versions of the Guidelines are subject to changes, which may alter this determination.
Nothing in this approval shall be construed as satisfying other applicable federal, state
or local statutes, ordinances or regulations.
FILE COPY
Cr,
Max Linden
City of Yakima - Wastewater Division
October 26, 2005
Page 2
You have the right to appeal this approval to the Pollution Control Hearings Board.
Pursuant to chapter 43.21B RCW, your appeal must be filed with the Pollution Control
Hearings Board, and served on the Department of Ecology, within thirty (30) days of the
date of your receipt of this document.
To appeal this action or decision, your notice of appeal must contain a copy of the
Ecology order, action or decision you are appealing.
Your appeal must be filed with:
Pollution Control Hearings Board
4224 - 6th Avenue SE, Rowe Six, Bldg. 2
P.O. Box 40903
Lacey, Washington 98504-0903
Your appeal must also be served on:
Department of Ecology
Appeals Coordinator
P.O. Box 47608
Olympia, Washington 98504-7608.
In addition, please send a copy of your appeal to:
G. Thomas Tebb
Section Manager/ Water Quality Program - CRO
Department of Ecology
15 West Yakima Ave., Ste 200
Yakima, WA 98902-3452
If you have any questions or need any additional information, please don't hesitate to
contact David Dunn, Facility Manager, at (509) 454-7846..
Sincerely,
CII:Ci
omas Tebb L.E.G.
Section Manager
Water Quality Program
GTT:DCD:WV
cc: Kenyon Hunt, P.E. - Black & Veatch
WASHINGTON STATE WATER POLLUTION CONTROL REVOLVING FUND
PROJECT ENVIRONMENTAL CLASSIFICATION/DOCUMENTATION CONCURRENCE
Application Number:
Applicant: City of Yakima
Project Title: City of Yakima — 2004 Wastewater Facilities Plan
The Program Manager for the Water Quality Program has reviewed the attached documents and concurs
that the proposed project:
1. ❑ Meets the criteria for a Categorical Exemption per WAC 197-11-800 (*) and no further
environmental documentation is required.
2. ❑ Requires the preparation of an environmental checklist and Determination of Nonsignificance.
3. ❑ Requires the preparation of an environmental checklist and Determination of Significance and
that an Environmental Impact Statement will subsequently be prepared.
4. ❑ Approval of the scoping process document.
5. ❑ Approval to circulate checklist and Determination of Nonsignificance.
6. 0 Approval to circulate Enviromnental Impact Statement.
7. ® SEPA process complete.
Type of environmental document prepared: SEPA checklist
Date Approved: 1/19/2005
8. 0 NEPA process complete.
Type of environmental document prepared:
Date Approved:
9. ® The subject project is in compliance with the State Environmental Review Proc
ess.
di. fig
4.
1 0124O 5.
Date of Approval
* Write in specific exemption category
m ' s Tebb , S- tion Supervisor
ater Quality Program
Department of Ecology
BLACK & VEATCH
LETTER OF TRANSMITTAL
4800 MEADOWS ROAD, SUITE 200
LAKE OSWEGO, OR 97035
To: David Dunn
Organization: Department of Ecology - Central
Regional Office
Address: 15 West Yakima Avenue, Suite 200
Yakima, WA 98902-3401
WE ARE SENDING YOU:
Black & Veatch Corporation
FAX: (503) 697-3699
PHONE: (503) 699-7556
Date: 10/20/05
Project #: 132965.3300
File #: B-1.0
Phone:
DATE
COPIES
DESCRIPTION
10/20/05
1
Yakima Regional WWTP 2004 Facility Plan - title sheet
THESE ARE TRANSMITTED AS CHECKED BELOW:
n For Approval
REMARKS:
n For your use n As Requested
For Review & Comment
co: Max Linden
File
SIGNED:
PRINTED: Kenyon Hunt
If enclosures are not as noted, kindly notify us at once.
pi OFFce
Reserved C3-
OCT
Z 1 zoos
GlONOcc-
�n
�y!
Response to Department of Ecology comments on the Draft 2004 WW Facility Plan
General Comments
Comment 1. Page 2-21 states that DOE is considering ground water protection
regulations. WAC 173-200 — Water Quality standards for Ground Waters of the State of
Washington was promulgated in 1990.
Response 1. The text will be corrected.
Comment 2. Page 10-15 indicates the I/I is excessive, as does the City's 2003 I/1 report
to the department. In the past, the city has discussed a plan for evaluating and ranking
I/I removal projects in the collection system. What is the status of this report? Prior to
considering any upgrades that are hydraulic bottlenecks (i.e. additional clarifiers), the
cost effectiveness versus I/1 reduction must be considered.
Response 2. We have been implementing an ongoing Manhole rehabilitation project
since 1998, as noted in the 2003 I&I Evaluation. Also stated in the evaluation was the
documentation and prioritization of existing infiltration and inflow problems to be
implemented. The city is in the process of prioritizing these to be repaired. The city is in
the process of purchasing a manhole grouter and sewer pipe grouter for manhole,
sideline, and pipe repair. This information will be reported in the 2004 I&I Report. We
are not considering any upgrades that are hydraulic bottlenecks in this facility plan, but if
there were the cost effectiveness versus I/I reduction would be considered.
Comment 3. Page 2-19 states that the City's treatment plant is designated Reliability
Class II. The Department concurs with this designation. At several later points in the
report, processes are evaluated against the more stringent Class 1 criteria, where Class
II criteria should apply.
Response 3. In WDOE's review of the previous facility plan, (Letter from Norman
Hepner dated 11/30/2000), it was stated: "The City of Yakima is currently classified a
Class 2 reliability facility. The consultant should- review and modify, as necessary, the
reliability discussion of each process component and provide a discussion for the need of
the facility to be Class I." This is why Class I criteria is discussed.
Comment 4. The draft plan does not establish the design capacity of the existing plant.
Without this analysis the Department cannot finalize the permitted load to the treatment
plant.
Response 4. The design capacities are found in section 5.3.1 page 5-16 of the Facility
plan. In section 5.3,1 Plant Capacity (pg. 5-16) the opening sentence should read: "The
total capacity of the biological system, including primary clarifiers, trickling filters,
trickling filter clarifier, aeration basins, and secondary clarifiers, is 53,400 ppd of total
influent BOD during maximum month loading conditions with Del Monte loads." The
2
corresponding flows of 14mgd should be deleted and 53,400ppd is the BOD design
capacity of the existing plant. On page 5-17 in the first Paragraph below Figure 5-5 the
biological system design �c4p ���is 1.5mgd.
Comment 5. In several places the report simply asserts capacity values for process
components. Calculations are typically not provided The mass balance was not
provided for the overall process. Provide the calculations or describe the basis for
process evaluations or treatment unit capacities.
Response 5. For processes that hydraulic limits such as clarifiers, the capacity
calculation involves applying the appropriate WDOE limiting surface overflow rate
(gpd/sf) multiplied times the surface area (sf) to obtain the capacity.
Mass balance sheets are provided to show the basis for design of the trickling filter and
the activated sludge processes. In the mass balance sheets, trickling filter/clarifier
performance is based on data from 2002. The aeration basin performance was twined _b di›.w>s
determined using a B&V complete mix activated sludge model. cic sent+•
Comment 6. The Department has several questions regarding the process model
referenced on page 5-14. Provide the mass balance for review.
Response 6. Mass balance sheets are provided (enclosure) for annual average and
maximum month conditions.
Comment 7. The report typically describes the capacity of the trickling filters and
aeration basin systems in terms of flow (MGD). This is misleading because the waste
strength affects the `flow" capacity. To be consistent, describe the capacity of the system
to oxidize BOD in lbs/day.
Response 7. We concur with this comment and used organic load to calculate the
/capacity of biological processes.
Comment 8. Modem the Metals Study Scope of Work (Appendix E) to include an
evaluation of hardness adjustment for the City's source water. Metal toxicity is highly
dependant on water hardness. In fact, the city's influent metals concentrations are not
significantly higher than other cities; the City's extraordinarily low water hardness was
the primary cause for metals limits.
Response 8. The scope will be modified as indicated evaluating hardness addition at the
WWTP.
Comment 9. Appendix F — Mixing zone study. This was previously reviewed in Aug '03.
Based on the Departments review, it appears reasonable to increase the 7Q10 used for
permitting to 834 cfs from 632 cfs.
3
V
V
Response 9. Where did the 834 cfs you refer to come from? The 7Q10 used in the study
were 908 and 899 cfs.— ��rFib��;rr�'(S (To, f 4\6)3
Comment 10. The final report must describe compliance with SEPA and NEPA if
applicable.
Response 10. The city has provided extended public comment and review and will
comply with SEPA as well as submitting an Environmental Report to the department
soon. The State Environmental Review Process (SERP) has been documented and will
be forwarded to the department for inclusion into the Facility Plan also.
Projected Waste Loads (Chapter 4)
Comment 1. Table 4-3 uses ammonia data, and appears to underestimate the nitrogen
loadings to the plant by approximately 20%. TKNdata available from June 2003 to June
2004 indicate an average annual loading of 2,330 ppd. These low estimates will impact
the design of the activated sludge and aeration systems. The BOD/TKN ratio appears to
be slightly greater than 10;1, indicating the highly industrial nature of the waste stream.
Response 1. The most recent data referred to was not available at the time of this analysis
and our analysis was limited to 2000-2002. However, this does not appear to be a
problem. Table 4-3 shows the annual average ammonia load, while Table 4-4 shows the
maximum month ammonia load of 2,822 ppd. The maximum month load is used as the
basis of design, so this covers the higher average that occurred recently. clio4 v►:i 56/1/1-
Comment
6iit=
Comment 2. What is the basis for the assumption that flows will decrease drastically in
the next 20 years (Section 4.3.2) ? This plan does not propose the type of aggressive 1/I
removal program that would justO, this assumption.
Response 2. Based on correlating seasonal operation of the regional irrigation system
with WWTP flows, it is confidently estimated that infiltration from the operating
irrigation system in to the sewer system adds approximately 3 mgd to the WWTP
influent. As indicated in the 2002 and 2003 I&I Evaluations the plants high flows occur
in late summer to early fall. This is typically the case because the Yakima area is heavily
irrigated with many canals and old pipe running through the city limits. Leakage from
these canals and pipes contributes significantly to the shallow ground water table that
runs under the City of Yakima and along the Yakima River. When the irrigation canals
are shut down in the fall the City's treatment flows are reduced significantly (by up to 3
million gallons per day over night) and when they are turned back on in the spring the
plant flows begin to increase and peak out in late summer and early fall. For the Facility
Plan, it was assumed that this excess flow would be reduced over time by the 308
Irrigation System Project sponsored by the City of Yakima Water and Irrigation
Department that is being implemented to increase the efficiency of the irrigation system.
Headworks
4
Comment 1. The Bar Screen and the Grit system do not appear to meet redundancy
requirements. If one unit is out of service peak flows will exceed the capacity of the
remaining unit. Discuss the resulting impact to the process (sewage overflow, poor
screenings removal, equipment damage). Evaluate the need for additional redundancy.
Response 1. Reliability Class I and Class II standards require that facilities "with only
two bar screens shall have at least one bar screen designed to permit manual cleaning."
Though somewhat difficult this condition is met as both mechanically cleaned screens
can be manually cleaned as necessary. There is no Class I or II reliability requirement for
grit removal. — . �A.,t 6,u�r,� i'P 0.4,445 1s eF,e,-,4 f
t/Comment 2. It is not clear from the text or figures that both flumes can operate in
parallel and record the totalized flow. Is this mode of operation possible?
Response 2. The two influent channels can operate individually or at the same time in
parallel. Two parshall flumes (one in each channel) measure flow and the results are
totalized. Text will be clarified as necessary.
Primary Clarification
Continent 1. Page 5-14 indicates the primary clarifiers remove 36% of the BOD and
51% of the TSS. Do these estimates consider the impact of thickening trickling filter
solids in the primary clarifiers.
Response 1. The primary clarifier removal rates are based on actual performance data
under current operating conditions, which involve pumping trickling filter solids to either
the DAFTs or the primary clarifiers via the headworks. Similar operation and
performance is assumed for the future.
I Comment 2. I can not duplicate the calculations that lead to the surface overflow rates
} shown on page 5-21.
Response 2. The current average flow condition is listed in Table 4-1 and 4-4 as
11.3 mgd. The four 90 -foot -diameter primary clarifiers have a combined surface area of
25,447 sf. Therefore, the average SOR is 11.3 mgd/25,447sf or 444 gpd/sf. The peak
hour flow is shown on Table 4-4 as 24 mgd, which yields an SOR of 943 gpd/sf, not
1,249 gpd/sf. This value will be corrected.
L./ Comment 3. Page 5-22 mentions grease and plugging problems in the primary
clarifiers. While the plan proposes no specific solution preventing grease discharges
through education and the pre-treatment program should be considered.
Response 3. At the Time this Draft was prepared our pretreatment program had not been
fully implemented. Since the submittal of the Facility plan the City's Pretreatment
Program is implementing a fat, oil, and grease (FOG) program to all businesses that have
the potential to introduce FOGs into the City's publicly owned treatment works (POTW).
5
This includes all food establishments, auto repair shops, auto detail shops, and car
washes.
Heavy FOG concentrations have the potential to cause sewer back-ups within the
collection system, causing flooding of wastewater into residential homes and businesses.
It also interferes with the process at the POTW. Not only is this an extremely expensive
and unpleasant situation, it is also a health hazard. It costs an average of $300,000 per
year for the City to manage the problems caused by FOGs. Unfortunately, the burden of
paying this cost is passed onto the ratepayers of Yakima.
For reasons mentioned, the Wastewater Division feels that this is an extremely important
and worthwhile program to be initiated.
The program will consist of three main components, education, testing, and inspections.
1. Education: Pretreatment has put together a FOG educational packet to be
distributed to all the restaurants discharging to the City's POTW. Educating the
managers of facilities that introduce FOGs into the POTW about proper FOG
disposal is the first and most important step in implementing the program. The
packet consists of an outline of each restaurant's responsibility to control the
discharge of FOGs, a Pretreatment fact sheet, a copy of the City of Yakima's local
limits, and a brochure on the best management practices (BMPs) on FOGs. This
includes procedures for preventing FOGs from entering the wastewater and the
maintenance of a grease trap. Brochures of the BMPs are also available in
Spanish. An educational packet for the auto repair shops, auto detail shops, and
car washes, will soon follow.
1. Testing: The City of Yakima conducts FOG testing to enforce the strict FOG
limit of 100 mg/L. The limit is very much obtainable if best management
practices (BMPs) are used in conjunction with a grease trap or oil interceptor.
2. Inspections: Inspections will be conducted by the Pretreatment Program to ensure
that BMPs for FOGs are being implemented and that grease traps or oil
interceptors are being cleaned out on a regular basis. Responsibility will fall on
the business owners or managers for maintaining and presenting to Pretreatment,
upon inspection, manifests indicating the cleaning schedule of the grease trap or
oil interceptor. An inspection will be conducted at each business several times
per year, as to reinforce the importance of continuing education and compliancy.
Comment 4. It is unclear how replacing the sluice gates will solve the flow splitting
problem into the primary clarifiers. Consider an energy dissipating weir or other
hydraulic mechanism.
Response 4. As discussed on page 6-2, the un -equal flow split is not ideal, but
manageable by operations staff. The purpose of the improvement is to provide isolation
gates that do not leak. When this improvement is designed, further investigation will be
given to methods for improving the flow split.
6
Trickling Filters
Comment 1. Page 5-14 assumes that the trickling filters can accept a surface load of
90 lb/kcf/day. Metcalf & Eddy indicate that 601b/kcf/day is a more appropriate
maximum for rock trickling filters. It seems likely that trickling filter performance would
degrade if loaded at 90 lb/kcf/day. Figure 5-6 seems to support this.
L56
.r. rlrSQ c SSo,.rAOi✓
Response 1. Page 5-14 refers to the detailed analysis of trickling filters in ° ' G(`' k�
Section 5.4.3.3, which justifies the loading rate on page 5-25 in the following statement:
"The organic loading rate is limited to 90 lb/kcf/day, because the units have demonstrated
effective treatment under those conditions as illustrated in Figure 5-6."
As shown on Figure 5-6, effluent BOD increases with higher load, but limiting the load
to 60 Ib/kcf/day requires bypassing additional load to the aeration basins and diminishes
the overall capacity of the existing system. Therefore, optimum secondary treatment
capacity is obtained by optimizing the load to the trickling filters. It was noted in the
facility plan that excessively high loading rates could lead to problems such as media
plugging, so the upper limit for normal operation was set at 90 lb/kcf/day, which has been
demonstrated to be effective. Higher loading rates are achievable because of the motor
driven distribution arms, which allow for greater flushing intensity across the media.
The Metcalf & Eddy reference is a "rule of thumb" guideline that is appropriate for some
rock trickling filters, but higher rates are also used. At another municipal facility, B&V
recently evaluated rock trickling filters with a loading rate of 72 ppd/kcf. It should be
noted that the Yakima facility experiences the high loading rates only during the canning
season, so the short time span may be a factor in avoiding problems.
Comment 2. Figure 5-6 shows approximately 30% BOD removal through the trickling
filter process. Page 5-14 states the assumption that the tricklingfilters remove 40% of
the BOD and 60 percent of the TSS. Do both of these estimates make the same
assumptions? Do they include the trickling filter clarifier or just the trickling filters
themselves?
Response 2. Figure 5-6 presents a plot of total BOD data across the trickling filter only.
It was used to demonstrate that successful treatment was obtained at 90 ppd/kcf BOD
loading. The trickling filter process converts soluble BOD (SBOD) into suspended
material, which is then removed in the trickling filter clarifier. Page 5-14 refers to
removals across the trickling filter clarifiers only. The removal across both trickling
filters and clarifier is about 64 percent BOD and 57 percent TSS as indicated by data
from 2002 after the clarifier was placed in operation. This is shown on the attached mass
balance sheets. (;tr i. i M ue b
Comment 3. Figure 5-6 shows three different sets of data. What does each represent?
They are not labeled in the figure.
7
Response 3. A version of Figure 5-6 with a legend is attached. The figure in the Facility
Plan will be upgraded to clarify.
l Comment 4. Was any analysis pet formed to support the assumption that plastic media in
1 the trickling filters would not increase their performance? It seems reasonable that
plastic media could double the available surface area for biological growth.
Response 4. Plastic media would increase the surface area, but the upper load limit of
90 ppd/kcf would remain the same, due to media structural concerns and potential
biomass buildup and plugging. Therefore, no additional firm capacity would be gained.
Removing the rock media and replacing with plastic media (which wouldn't add
capacity) would be almost as expensive as building new aeration basin volume, which
would increase the treatment capacity.
v Comment 5. What is the assumed recirculation rate for the trickling filters?
Response 5. As stated on page 5-24, the hydraulic limit of the trickling filters is 36 mgd
with three of the four pumps in operation. Typical operation is two pumps at 27.4 mgd.
With a base flow around 10 mgd that means there is 17 mgd of recirculation flow for a
ratio of 1.7:1.0.
0t Comment 6. How does the plant staff currently thicken trickling filter solids? What
thickening options does the existing plant allow? Page 5-1 indicates that the process
model was based on a 50-50 flow split between DAF and primary clarifiers, but Page 9-3
indicates that trickling filter solids cannot be sent to both the DAF and headworks at the
same time.
7
Response 6. Both statements are correct, the trickling filter solids flow is split 50-50 by
pumping to the DAF and headworks alternately.
Aeration Basins
Comment 1. The report cites three numbers as the "capacity" of the aeration basins,
53,400 lbs-BOD/day, 3,000 mg/L MLSS, and 14,400 scfm. Provide justification for these
capacities. Include aprocess evaluation that includes the trickling filters, the aeration
basins and aeration system. Include the mass balance with the analysis. Describe the
reactor kinetics. Calculate oxygen requirements.
Response 1. The capacity of the aeration basin is not reported to be 53,400 ppd BOD.
As stated on page 5-16: The total capacity of the biological system, including the primary
clarifiers, r riding, filters, trickling filter clarifier, aeration basins and secondary
clarifiers, 's 53,400 pd of total influent BOD. This includes the plant influent of 41,790-
ppd BOD an a Monte contribution of 11,610 ppd BOD, totaling 53,400-ppd influent
BOD. The aeration capacity is 15.0 mgd, corresponding to a BOD load of 18,015 ppd
and a TSS load of 12,760 ppd. These loads are shown in the 2019 MM mass balance
8
sheet and the corresponding Black & Veatch Activated Sludge Model for the 2019 MM
conditions.
The MLSS in the aeration basin was limited to 3,000 mg/L based on Black & Veatch
experience as well as information that the operations staff has experienced problems with
process upset at MLSS values in excess of this amount. MOP 8 also indicates that
conventional air activated sludge system MLSS concentrations ranging from 1,500 mg/L
to 3,000 mg/L are often used.
The 14,400 scfm firm capacity of the blowers is the scfin that can currently be provided.
As stated on page 5-29, the aeration is supplied to the basins fine bubble air diffuser
system via four multistage, positive displacement blowers. The blowers have a capacity
of 5,500 ICFM and 4,800 SCFM each, operated from 400 Hp motors. For three blowers
in operation, and one in stand-by, the capacity is 14,400 scfin. The Black & Veatch
Activated Sludge Model is attached for the maximum month 2024 conditions to indicate
the oxygen requirements of 10,530 scfm with five basins in service (4 current + 1 new),
as well as the mass balance for the process evaluation including the primary clarifier,
trickling filters, trickling filter clarifier, aeration basins, and secondary clarifiers.
The process evaluation completed as part of the plant capacity evaluation already
includes the trickling filters, aeration basin and aeration system. The mass balance
provided includes each of these processes. The mass balance was used in conjunction
with the Black & Veatch Activated Sludge Model.
The oxygen requirements are calculated for each of the design year increments, as shown
in the Black & Veatch Activated Sludge Model printout.
01/Comment 2. The plant will likely face discharge limitations for orthophosphate within
10 to 15 years. Investigate how phosphate treatment will be accornplished. Consider the
need to modem the plant to remove phosphate in each alternative considered.
A
Response 2. It is acknowledged that phosphorous limits may be faced in the timeframe
noted, which could probably be met by chemical addition or incorporation of an
anaerobic zone in to the aeration basin design. None of the facility improvements
evaluated precludes these possible approaches. We propose to add an additional segment
in Section 6 that will address this topic.
l) Comment 3. The alternatives considered in Chapter 6 cannot be objectively compared.
Use consistent assumptions for time frame and treatment requirements when comparing
alternatives.
Response 3. The current facilities have sufficient capacity until 2019. The addition of
an internal anoxic zone in the current aeration basins would provide denitrification until
2019. To maintain treatment consistency, alternatives were developed to determine how
the plant could meet the required effluent requirements at design years 2024 and, then, at
ultimate build out conditions. The time frames must be evaluated, as it compares the cost
9
of providing denitrification only with the current basins, with one additional basin up to
2024, or building two additional basins and providing capacity up to build -out conditions.
L /Comment 4. All of the alternatives presented appear to undersize the anoxic zone, which
is typically 30-40% of the aeration volume. No calculations are provided for
denitrification kinetics. Based on the numbers available, I calculate a nitrate removal
rate of 500 ppd, afraction of the total nitrogen loading. The anoxic zone is too large to
function effectively as a selector; the F/Mgradient is too small. I calculate an F/M of 1.4
across the zone. Perhaps with internal compartments an adequate gradient could be
maintained.
Response 4. Black & Veatch has never designed an anoxic zone larger than 25% of the
aeration volume and has experience with numerous facilities designed with anoxic zones
at 10% - 15% of the aeration volume that are providing complete denitrification. The
Black & Veatch Aeration Model shows complete denitrification with the provided anoxic
zones for maximum month conditions in 2019 and 2024. The BOD to TKN ratio is 7:2,
which provides a driving force that is capable of providing complete denitrification in the
current anoxic zone.
Comment 5. Evaluate an alternative that provides complete denitrification, which would
then allow the basin to operate at a MLSS greater than 3,000 mg/L. Also full consider
that denitrification will reduce the aeration requirements for the system. Compare the
total life cycle costs of the alternatives.
Response 5. The alternatives previously completed evaluate complete denitrification
(see comment 4). The Black & Veatch Aeration Model takes into account the reduction
in aeration requirements. Life cycle costs have already been completed. Operating
0 consistently at a MLSS greater than 3,000 mg/L is not recommended.
Comment 6. Page 6-15 recommends downsizing the capacity of the aeration blowers.
No justification is provided for this recommendation. Provide calculation for the system
aeration requirements. The final recommendation for the air system should address the
reported blower cycling. Evaluate an automatic feedback control loop to control DO in
the basins.
Response 6. The Black & Veatch Aeration Model calculates aeration requirements. The
2024 maximum month condition is attached and indicates the required scfm. Methods
for DO control will be addressed during subsequent design phases.
Secondary Clarification
F f k ,g11v15>
Comment 1. Calculations are generally not included for capacities presented in the
report. I can't duplicate the calculation on page 5-32 of peak hour overflow rate of
1030 gpd/sffor the Secondary Clarifiers. I can't duplicate the calculations on page 5-33
that lead to 15.98 and 16.3 as the flow capacities based on solids loading considerations.
10
Also the numbers in Table 5-8 don't match the MLSS concentration assumptions made
earlier in the chapter.
Response 1. At a peak hour flow of 24.0 mgd (from Table 4-4), and a surface area of
30,788 sf, the peak hour overflow rate would be 780 gpd/sf. This number will be
co The solids loading rates are calculated assuming 100% RAS and and shown in
the Black & Veatch Aeration model (2024 maximum month condition). These models
also show the MLSS concentrations for these conditions and match the numbers found in
Table 5-6.
Comment 2. The report recommends building a third secondary clarifier based on
meeting Class I reliability; however only class II reliability is required. Page 5-34
further indicates that the new secondary clarifier is required to protect against the event
that both the trickling filter clarifier and one of the secondary clarifiers are off line at the
same time. No mass balance or process calculations are provided to justify this
contention.
Response 2. See Response 3 to the General Questions regarding Class I and Class II
reliability. The discussion on page 5-34 does not justify a new secondary clarifier based
on Class I reliability, but on the potential for the solids loading limit of the existing
clarifiers to be approached if the (intermediate) trickling filter clarifier is offline and peak
influentcanning oa s are experienced. The enclosed process calculations for this
condition show this possibility.
Comment 3. What assumption went into the estimated WAS pumping rates? I can't
duplicate the flow rates presented on page 5-36.
Response 3. The Black & Veatch Aeration Model is used in determining WAS flow in
gpd. The conversion to gpm results in the numbers presented on page 5-36 for the 2024
annual average and maximum month conditions (5 total basins in service).
Comment 4. Chapter 5 concluded that the odor control system was functioning
adequately and effectively. Why are upgrades to the system ($1,112, 000) proposed in
chapter 6?
Response 4. The "upgrades" are the inclusion of additional point sources, such as the
influent channel and primary clarifier effluent launders, in to the existing system as
detailed in Table 6-18 (page 6-41) and summarized on page 12-17 s
—'ro �/ ��1 /1 anl,tiy h�zess,/
Disinfection
Comment 1. The UV systems evaluated do not appear to be capable of disinfecting peak
flows. In addition to average annual flow, disinfection systems need to disinfect peak
flows.
11
Response 1. The UV systems evaluated were sized to provide a bioassay dose of 30
mJ/cm2 at peak flow conditions. Based on B&V experience, a review of UV information
in the literature, and information from manufactures, the facilities will achieve a 30 -day
geometric mean of 200 fecal coliforms per 100/mL at a transmittance of 65%. Great
Lakes - Upper Mississippi River Board (Ten States standards) "Recommended Standards
for Wastewater Facilities" Section 104 recommends a dose 30 mJ/cm2. Dose can be
expressed as 30,000 uW-sec/cm2, 30 mJ/cm2 (watt -sec = Joule) or 300 J/m2. During
schematic design, water quality parameters will be confirmed through on-site testing.
After the on-site testing has been completed, dose requirement will be modified to ensure
compliance with permit bacterial requirements.
L/ Comment 2. The draft plan does not make a recommendation regarding disinfection.
The final report must contain a concrete proposal.
Response 2. The final plan will indicate the City's desire to replace the gas chlorine
system with UV disinfection.
Solids Handling
Comment 1. The report proposes a second DAFT unit ($2,000,000) to provide
redundancy. In general Ecology only requires redundant equipment for the main
wastewater treatment system, not the solids thickening or treatment. Evaluate the plant's
ability to continue to provide adequate solids treatment if the DAF is offline for routine
maintenance. Consider the ability of the digesters to thicken through decanting.
Response 1. The proposed digester complex provides 1.7 MG of existing primar
tankage plus 0.6 MG of new tank , for a total of 2.3 MG. if thickening i : out o
service a h lie -flow -to aG ckup s a Table, the digesters at 2024 maximum month
'conditionsis J00 gpd. This equates to a 4.5 day SRT in the primary digester
tankage. Depending on decanting _ana_erobicall di ested sludge for asigaificant period
to make up for this deficit is not recommended due to potentially poor settling and decant
properties.
S �ti�`/f,/�cldS
�J'
Comment 2. The report proposes a new primary digester ($5,384,000) w provide
redundancy. In general, Ecology only requires redundant equipment for the main
wastewater treatment system, not solids thickening or treatment. Evaluate the plant's
ability to comply with the 503 regulations with one digester cell is offline for routine
maintenance. Evaluate the relative costs of constructing a new prima?), digester cell to
another method. At a minimum consider: 1) Meeting 503 requirements by testing, 2)
meeting the requirements by lime application, 3) hauling sludge to NSF composting
facility for further stabilization.
iawl1t'71J 6:4vt'l) h.
Response 2. Anaerobic digestion systems are typically designed to provide enough
secondary digestion tankage to support 40 CFR Part 503 -designated 15 -day detention
requirements for Class B pathogen treatment in the event that a primary tank is out of
service. Primary digester tanks are expected to be out of service at least once every 5
12
years for cleaning and typically require 60 to 90 days to clean the tankage and restore full
digestion. Fecal coliform monitoring can be used to show pathogen compliance in plac
of the 15 day SRT; however, a shortened SRT ma result in difficulties in meeting t - 38
percent volatile solids reduction requi omen an. may affect digester stability. /G'i`g"
Alkaline addition is not recommended as a back-up stabilization method in this case for
the following reasons:
• Alkaline storage and feed equipment is not well suited to sitting idle for long
periods of time due to clogging and chemical degradation.
• A different, additional treatment process complicates operations and maintenance
and is not desirable as a backup system.
• Alkaline stabilized solids may not be suitable for the NSF land application
program due to predominant soil types at the application area.
The City may have opportunities to further compost the solids at the NSF facility and can
investigate this as an aterns is ee tmmal use; however, while NSF is permitted to accept less
than Class B in its composting facility, according to NSF staff, all solids accepted at the
composting facility to date have met Class B requirements. Composting wastewater
solids that have not met Class B pathogen reduction and adequate volatile solids _
destruction lead to increased odor production during the composting process. r lu
Comment 3. Tables 5-9 and 5-11 appear inconsistent. Provide the solids treatment
system mass balance.
Response 3: The Current solids values in Table 5-9 reflect 2002 - 2003 operating data
and 2024 projections. The solids values in Table 5-11 reflect 2004 and 2024 projected
solids quantities. Note that the 2024 DAFT loading rates are based on 100 percent of
trickling filter solids being thickened through the DAFT to allow flexibility of operation,
while the 2024 • : feed was based on 50 percent of the trickling filter solids
thicken s oug a DAFT to reflect the most common practice at the plant. Digester
feed :ries from 3.9 rcent TS if all trickling filter solids are thickened through the
D ' to 4.1 percen S if only 50 percent of the trickling filter solids are thickened
thr • ugh the D . The solids values in the two tables have been adjusted to eliminate
rou • d -off v nces and are presented below. The corrected tables are enclosed.
Comment 4. The report proposes a new centrifuge and polymer unit ($3,103,000) to
provide redundancy. In general, Ecology only requires redundant equipment for the
main wastewater treatment system, not solids thickening or treatment. Evaluate the
plant's ability to store solids while the centrifuge is offline for routine maintenance.
Evaluate the cost of hauling liquid sludge to natural Selection Farms during this time
period.
Response 4. The existing 0.65 MG of secondary digestion tankage provides 5 days
detention at 2024 design conditions. Since the manufacturer typically performs major
13
centrifuge maintenance on the bowl or scroll, it is not uncommon to have a centrifuge out
of service for several weeks durin' maintenance. The 5 days of detention in the
secondary tank cannot support extended centrifuge downtime. NSF will accept liquid
Class B biosolids for land application. Based on conversations with NSF staff, the cost to
haul and land apply liquid sludge is 2 to 3 times the cost of hauling and land applying
dewatered cake. It may be less expensive over the life of the project to use liquid land
application as a backup to cake dewatering; however this option decreases the City's
flexibility of outlets and relies on acquisition and rapid res onse to spppply tanker trucks
to haul the sludge. -- ryt 'dot. 6i,Pc c 0/.1 ,44,(,,q,
(Comment 5. Page 9-10 discusses the centrate equalization facility. Evaluate the process
impact of returning the centrate to headworks, the trickling filter pump station, or
directly to the aeration basin.
Response 5. Further design efforts will look at the capability to provide flexibility for
returning this side stream to either the trickling filter pump station or to the aeration basin
influent. There would be no treatment benefit provided by the headworks or primary
clarifiers for this flow, as the primary constituent of concern is ammonia.
Enclosures
14
25,000
20,000
b
15,000
0
10,000
w
5,000
0
0
Figure 5-6. Trickling Filter Loading Rate
5,000
10,000
15,000
20,000
TF Influent BOD (ppd)
25,000
30,000
35,000
•2001-2002 Baseline • 2001 Canning • 2002 Canning
•
•
•
,•
.
•
.
•
.
.
•
.
•
.
.
.
•
5,000
10,000
15,000
20,000
TF Influent BOD (ppd)
25,000
30,000
35,000
BLACK & VEATCH ACTIVATED SLUDGE MODEL
OWNER Yakima
PLANT WWTP
PROJ NO.
WORK No TF Clarifier
MM 2009 Del Monte
4 basins in service
COMPUTED BY ADG
DATE 9/22/2004
B&V FILE NO.
CHECKED BY GVD
DATE 9/22/04
INPUT TO CMAS MODEL
Tot Vol, cu ft 561,600 alpha
Anoxic VoI,(%) beta
Tot det Tim, hr Min DO @Pk, mg/I
Anox Det Tim,hr Min DO @Ave,mg/I
Inf BOD, mg/I 172 Std Cs20, mg/I
Inf TSS, mg/I 167 Amb Cs, mg/I
Eff TSS, mg/I 15 SRT, days
NonBVSS 0.30 RAS TSS, mg/I
VSS/TSS 0.82 MLSS, mg/I
Inf. Ma, mg/I 40 Inf TKN, mg/l
Flow, mgd 13.1 NO3-N, mg/I
MLSS Rec Q, mgd Min Eff Alk, mg/l
Carb Peak Factor 1.3 Inf alk, mg/I
Nitr Peak Factor 1.3 Temp, C
0.65 Elevation, ft 1065
0,95 Station Pres,psi 14.15
1 SW depth,ft 26
2 Diffus depth, ft 25
11.10
10.45 FINAL CLARIFIERS
8 No. of Clarifiers 2
7,500 Clarifier SWD, ft 15
Dia. of Clarifier, ft 140
20 Design SOR, gpd/sf
Floc Well HRT, min
100 Floc Well SWD, ft
270 No. of Floc Turbines
20.78 Max G, 1/sec
Diffuser type (Gen. Fine =1, Coarse = 3, Stat. Tube = 4)
1
STEADY STATE OPERATING CHARACTERISTICS
FINAL CLARIFIERS
Tot Det time, hr 7.68 Tot Vol, cf
Oxic Det time,hr 7.68 Oxic Vol, cf
Anox Det Time,hr 0.00 Anoxi Vol, cf
CALC. SRT 8.89
SRT, days 8.00 BOD Load, ppd/kcf
Req SRT, days 5.69
Min SRT, days 3.00
561600
561600
0
34
ClarifierTot. Area, sf 30787
SOR, gpd/sf 426
Dia. of Clarifier, ft 140
SLR(100%RAS),ppd/sf 26
Clarifier HRT, hrs 6.3
Floc Well Diam., ft #DIV/0!
Turbine Power,bhp/unit #DIV/0!
CARBONACEOUS
NITROGENOUS
COMBINED
Unmet Frac, mg/I 1.40
Act Mass, mg/I 912
End Mass, mg/I 739
MLVSS, mg/l 2678
MLSS, mg/I 3594
F/Mv Ratio 0.20
Eff BOD, mg/I 4.4
WAS, ppd 14097
WVS, ppd 10503
WMa, ppd 3577
AvgdO/dt, mg/l/h 33.9
Pk dO/dt, mg/l/h 37.8
Eff SNH, mg/I
Act Mass,mg/I
End Mass, mg/I
MLVSS, mg/I
MLSS, mg/I
WAS, ppd
WVS, ppd
WMa, ppd
AvgdO/dt, mg/l/h
Pk dO/dt, mg/l/h
Alk Req, mg/l
Eff NO3, mg/I
Eff Alk, mg/I
Eff TKN, mg/I
N in WAS, mg/I
Min N Req, mg/l
0.02
63
51
114
126
551
492
263
8.8
11.3
0
13.7
172
0.8
5.43
6.26
Unmet Frac, mg/I 1.40
Act Mass, mg/I 975
End Mass, mg/l 791
MLVSS, mg/l 2792
MLSS, mg/I 3720
F/Mv Ratio 0.19
Eff BOD, mg/I 4.5
WAS, ppd 14648
WVS, ppd 10995
WMa, ppd 3840
AvgdO/dt, mg/I/h 42.8
Pk dO/dt, mg/I/h 49.0
Pk Kla 20, l/h 8.4
Ave KLa 20,1/h 8.2
Ave TAOR, pph 1498
Ave SOTR, pph 3190
Pk TAOR,pph 1718
Pk SOTR, pph 3249
RAS Flow, mgd 12.4
WAS Flow, gpd 234189
DENITRIFICATION
Ave ANXdO/dt,mg/I/h 0.0
Ave Den AOS, pph 0
Ave Anox AOR, pph 0
Pk ANOdO/dt,mg/l/h 0.0
Pk Den AOS, pph 0
Pk Anox AOR, pph 0
AERATION EQUIPMENT DESIGN
INPUT TO AERATION MODEL
DIFFUSER SYSTEM
Design SOTR, pph
3249
Lateral Spacing, ft
4
Diffuser Area, sf
0.410
Airflow per diffuser, scfm/diff
3.5
Min Air for Mixing, scfm/kcf (Fine = 15, Coarse = 20)
15
Number of Diffuser
BLOWER SYSTEM
Peak Ambient Temp, F
110
Average Ambient Temp, F
65
Blower Efficiency,%
55
Headloss thru Diffuser (Fine = 1, Coarse = 0.5)
1
MECHANICAL AERATION
Design SOTR, pph
0
Transfer Efficiency, lbs 02/hr/bhp
(Low Speed: 3.2 for <75 HP; 3.0 for 75<HP<100; 2.8 for HP>100);(High Speed = 2.0)
Aerator Size, nhp/unit
Minimum mixing power, bhp/kcf
0.75
Motor Service Factor, bhp/nhp
0.87
OUTPUT FROM AERATION MODEL
DIFFUSER SYSTEM
Process Airflow,scfm
8263
Minimum Air for Mixing, scfm
8424
Design Airflow (without 10% safety factor), scfm
8424
Oxygen Transfer Efficiency (OTE), % (OTE = 0 for Mixing limited Cond.)
0.0
Number of Diffusers
2407
Airflow per diffuser, scfm/diff
3.5
Tank Area/Diffuser Area (At/Ad)
21.9
Diffuser Density, sq ft/diff
9.0
BLOWER SYSTEM
Blower HP at Peak Temperature, whp
697
Blower HP at Ave. Temperature, whp
642
Blower HP for Mixing at Ave, Temperature, whp
642
MECHANICAL AERATION
Total Aerator Process Power, bhp
0
Total Aerator Mixing Power, bhp
0
Design Aerator Power, bhp
0
Number of Aerators
0
BLACK & VEATCH ACTIVATED SLUDGE MODEL
OWNER Yakima
PLANT WWTP
PROJ NO.
WORK
MM 2019 Del Monte
4 basins in service
COMPUTED BY ADG
DATE 9/14/2004
B&V FILE NO.
CHECKED BY GVD
DATE 9/14/2004
INPUT TO CMAS MODEL
Tot Vol, cu ft
Anoxic Vol,(%)
Tot det Tim, hr
Anox Det Tim,hr
Inf BOD, mg/I
Inf TSS, mg/1
Eff TSS, mg/l
NonBVSS
VSS/TSS
Inf Ma, mg/l
Flow, mgd
MLSS Rec Q, mgd
Carb Peak Factor
Nitr Peak Factor
561,600 alpha
beta
Min DO @Pk, mg/I
Min DO @Ave,mg/I
144 Std Cs20, mgll
102 Amb Cs, mg/I
15 SRT, days
0.30 RAS TSS, mg/I
0.82 MLSS, mg/I
24 Inf TKN, mg/I
15.0 NO3-N, mg/l
Min Eff Alk, mg/I
1.3 Inf alk, mg/l
1.3 Temp, C
0.6 Elevation, ft 1065
0.95 Station Pres,psi 14.15
1 SW depth,ft 26
2 Diffus depth, ft 22.8
11.00
10.35 FINAL CLARIFIERS
8 No. of Clarifiers 2
8,000 Clarifier SWD, ft 15
Dia. of Clarifier, ft 140
20 Design SOR, gpd/sf
Floc Well HRT, min
100 Floc Well SWD, ft
270 No. of Floc Turbines
20.78 Max G, 1/sec
Diffuser type (Gen. Fine =1, Coarse = 3, Stat. Tube = 4)
1
STEADY STATE OPERATING CHARACTERISTICS
FINAL CLARIFIERS
Tot Det time, hr
Oxic Det time,hr
Anox Det Time,hr
CALC. SRT
SRT, days
Req SRT, days
Min SRT, days
6.72 Tot Vol, cf
6.72 Oxic Vol, cf
0.00 Anoxi Vol, cf
8.89
8.00 BOD Load, ppd/kcf
5.69
3.00
561600
561600
0
32
ClarifierTot. Area, sf 30787
SOR, gpd/sf 488
Dia. of Clarifier, ft 140
SLR(100%RAS),ppd/sf 25
Clarifier HRT, hrs 5.5
Floc Well Diam., ft #DIV/0!
Turbine Power,bhp/unit #DIV/0!
CARBONACEOUS
NITROGENOUS
COMBINED
Unmet Frac, mg/I
Act Mass, mg/I
End Mass, mg/l
MLVSS, mg/I
MLSS, mg/l
F/Mv Ratio
Eff BOD, mg/I
WAS, ppd
WVS, ppd
WMa, ppd
AvgdO/dt, mg/l/h
Pk dO/dt, mg/l/h
1.34
819
664
2200
2873
0.23
4.8
10705
8197
3051
31.2
34.9
Eff SNH, mg/I
Act Mass,mg/I
End Mass, mg/I
MLVSS, mg/l
MLSS, mg/I
WAS, ppd
WVS, ppd
WMa, ppd
AvgdO/dt, mg/l/h
Pk dO/dt, mg/l/h
Alk Req, nig/I
Eff NO3, mg/I
Eff Alk, mg/I
Eff TKN, mg/I
N in WAS, mg/l
Min N Req, mg/I
0.02
72
59
131
144
631
561
297
10.9
13.9
0
14.9
163
0.9
4.13
5.07
Unmet Frac, mg/I 1.34
Act Mass, mg/l 891
End Mass, mg/I 723
MLVSS, mg/I 2331
MLSS, mg/I 3017
F/Mv Ratio 0.22
Eff BOD, mg/I 4.9
WAS, ppd 11336
WVS, ppd 8758
WMa, ppd 3348
AvgdO/dt, mg/l/h 42.1
Pk dO/dt, mg/!/h 48.9
Pk Kla 20,1/h 9.1
Ave KLa 20,1/h 8.9
Ave TAOR, pph 1476
Ave SOTR, pph 3414
Pk TAOR,pph 1712
Pk SOTR, pph 3510
RAS Flow, mgd 8.8
WAS Flow, gpd 169901
DENITRIFICATION
Ave ANXdO/dt,mg/l/h
Ave Den AOS, pph
Ave Anox AOR, pph
Pk ANOdO/dt,mg/l/h
Pk Den AOS, pph
Pk Anox AOR, pph
0.0
0
0
0.0
0
0
BLACK & VEATCH ACTIVATED SLUDGE MODEL
OWNER Yakima COMPUTED BY
PLANT WWTP DATE
PROJ NO. B&V FILE NO.
WORK CHECKED BY
MM 2019 Del Monte DATE
4 basins in service
ADG
9/14/2004
GVD
9/14/2004
AERATION EQUIPMENT DESIGN
INPUT TO AERATION MODEL
DIFFUSER SYSTEM
Design SOTR, pph
3510
Lateral Spacing, ft
3
Diffuser Area, sf
0.410
Airflow per diffuser, scfm/diff
1.5
Min Air for Mixing, scfm/kcf (Fine = 15, Coarse = 20)
15
Number of Diffuser
7600
BLOWER SYSTEM
Peak Ambient Temp, F
100
Average Ambient Temp, F
65
Blower Efficiency,%
55
Headloss thru Diffuser (Fine = 1, Coarse = 0.5)
1
MECHANICAL AERATION
Design SOTR, pph
0
Transfer Efficiency, lbs 02/hr/bhp
(Low Speed: 3.2 for <75 HP; 3.0 for 75<HP<100; 2.8 for HP>100);(High Speed = 2.0)
Aerator Size, nhp/unit
Minimum mixing power, bhp/kcf
0.75
Motor Service Factor, bhp/nhp
0.87
OUTPUT FROM AERATION MODEL
DIFFUSER SYSTEM
Process Airflow,scfm
7633
Minimum Air for Mixing, scfm
8424
Design Airflow (without 10% safety factor), scfm
8424
Oxygen Transfer Efficiency (OTE), % (OTE = 0 for Mixing limited Cond.)
0.0
Number of Diffusers
7600
Airflow per diffuser, scfm/diff
1.1
Tank Area/Diffuser Area (At/Ad)
6.9
Diffuser Density, sq ft/diff
2.8
BLOWER SYSTEM
Blower HP at Peak Temperature, whp
639
Blower HP at Ave. Temperature, whp
599
Blower HP for Mixing at Ave. Temperature, whp
599
MECHANICAL AERATION
Total Aerator Process Power, bhp
0
Total Aerator Mixing Power, bhp
0
Design Aerator Power, bhp
0
Number of Aerators
0
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BLACK & VEATCH ACTIVATED SLUDGE MODEL
OWNER Yakima
PLANT WWTP
PROJ NO. Complete Denitrification
WORK
MM 2019 Del Monte
4 basins in service
COMPUTED BY ADG
DATE 9/14/2004
B&V FILE NO.
CHECKED BY GVD
DATE 9/14/2004
INPUT TO CMAS MODEL
Tot Vol, cu ft
Anoxic Vol,(%)
Tot det Tim, hr
Anox Det Tim,hr
Inf BOD, nig/I
Inf TSS, mg/I
Eff TSS, mg/I
NonBVSS
VSS/TSS
Inf Ma, mg/I
Flow, mgd
MLSS Rec Q, mgd
Carb Peak Factor
Nitr Peak Factor
561,600 alpha
12.5 beta
Min DO @Pk, mg/l
Min DO @Ave,mg/I
144 Std Cs20, nig/l
102 Amb Cs, mg/I
15 SRT, days
0.30 RAS TSS, mg/I
0.82 MLSS, mg/I
24 Inf TKN, mg/I
15.0 NO3-N, mg/1
30 Min Eff Alk, mg/I
1.3 Inf alk, mg/l
1.3 Temp, C
0.6 Elevation, ft 1065
0.95 Station Pres,psi 14.15
1 SW depth,ft 26
2 Diffus depth, ft 22.8
11.00
10.35 FINAL CLARIFIERS
8 No. of Clarifiers 2
8,000 Clarifier SWD, ft 15
Dia. of Clarifier, ft 140
20 Design SOR, gpd/sf
Floc Well HRT, min
100 Floc Well SWD, ft
270 No. of Floc Turbines
20.78 Max G, 1/sec
Diffuser type (Gen. Fine =1, Coarse = 3, Stat. Tube = 4)
1
STEADY STATE OPERATING CHARACTERISTICS
FINAL CLARIFIERS
Tot Det time, hr
Oxic Det time,hr
Anox Det Time,hr
CALC. SRT
SRT, days
Req SRT, days
Min SRT, days
6.72 Tot Vol, cf
5.88 Oxic Vol, cf
0.84 Anoxi Vol, cf
8.89
8.00 BOD Load, ppd/kcf
6.50
3.43
561600
491400
70200
37
ClarifierTot, Area, sf 30787
SOR, gpd/sf 488
Dia. of Clarifier, ft 140
SLR(100%RAS),ppd/sf 25
Clarifier HRT, hrs 5.5
Floc Well Diam., ft #DIV/0!
Turbine Power,bhp/unit #DIV/0!
CARBONACEOUS
NITROGENOUS
COMBINED
Unmet Frac, mg/I
Act Mass, mg/I
End Mass, mg/l
MLVSS, mg/I
MLSS, mg/I
F/Mv Ratio
Eff BOD, mg/l
WAS, ppd
WVS, ppd
WMa, ppd
AvgdO/dt, mg/l/h
Pk dO/dt, mg/l/h
1.34
819
664
2200
2873
0.23
4.8
10705
8197
3051
31.2
34.9
Eff SNH, mg/I
Act Mass,mg/I
End Mass, mg/I
MLVSS, mg/l
MLSS, mg/I
WAS, ppd
WVS, ppd
WMa, ppd
AvgdO/dt, mg/l/h
Pk dO/dt, mg/l/h
Alk Req, mg/I
Eff NO3, mg/I
Eff Alk, mg/l
Eff TKN, mg/I
N in WAS, mg/I
Min N Req, mg/I
0.03
80
57
137
151
662
588
329
12.3
15.8
0
4.2
202
0.9
4.16
5.10
Unmet Frac, mg/I 1.34
Act Mass, mg/l 899
End Mass, mg/I 721
MLVSS, mg/I 2337
MLSS, mgll 3024
F/Mv Ratio 0.22
Eff BOD, mg/I 4.9
WAS, ppd 11367
WVS, ppd 8785
WMa, ppd 3380
AvgdO/dt, mg/l/h 42.8
Pk dO/dt, mg/l/h 47.6
Pk Kla 20, l/h 8.9
Ave KLa 20,I/h 9.0
Ave TAOR, pph 1313
Ave SOTR, pph 3036
Pk TAOR,pph 1459
Pk SOTR, pph 2991
RAS Flow, mgd 8.8
WAS Flow, gpd 170365
DENITRIFICATION
Ave ANXdO/dt,mg/l/h
Ave Den AOS, pph
Ave Anox AOR, pph
Pk ANOdO/dt,mg/l/h
Pk Den AOS, pph
Pk Anox AOR, pph
116.8
160
491
146.1
249
629
BLACK & VEATCH ACTIVATED SLUDGE MODEL
OWNER Yakima COMPUTED BY
PLANT WWTP DATE
PROJ NO. Complete Denitrification B&V FILE NO.
WORK CHECKED BY
MM 2019 Del Monte DATE
4 basins in service
ADG
9/14/2004
GVD
9/14/2004
AERATION EQUIPMENT DESIGN
INPUT TO AERATION MODEL
DIFFUSER SYSTEM
Design SOTR, pph
3036
Lateral Spacing, ft
3
Diffuser Area, sf
0.410
Airflow per diffuser, scfm/diff
1.5
Min Air for Mixing, scfm/kcf (Fine = 15, Coarse = 20)
15
Number of Diffuser
7600
BLOWER SYSTEM
Peak Ambient Temp, F
100
Average Ambient Temp, F
65
Blower Efficiency,%
55
Headloss thru Diffuser (Fine = 1, Coarse = 0.5)
1
MECHANICAL AERATION
Design SOTR, pph
0
Transfer Efficiency, lbs O2/hr/bhp
(Low Speed: 3.2 for <75 HP; 3.0 for 75<HP<100; 2.8 for HP>100);(High Speed = 2.0)
Aerator Size, nhp/unit
Minimum mixing power, bhp/kcf
0.75
Motor Service Factor, bhp/nhp
0.87
OUTPUT FROM AERATION MODEL
DIFFUSER SYSTEM
Process Airflow,scfm
6421
Minimum Air for Mixing, scfm
7371
Design Airflow (without 10% safety factor), scfm
7371
Oxygen Transfer Efficiency (OTE), % (OTE = 0 for Mixing limited Cond.)
0.0
Number of Diffusers
7600
Airflow per diffuser, scfm/diff
1.0
Tank Area/Diffuser Area (At/Ad)
6.1
Diffuser Density, sq ft/diff
2.5
BLOWER SYSTEM
Blower HP at Peak Temperature, whp
559
Blower HP at Ave. Temperature, whp
524
Blower HP for Mixing at Ave. Temperature, whp
524
MECHANICAL AERATION
Total Aerator Process Power, bhp
0
Total Aerator Mixing Power, bhp
0
Design Aerator Power, bhp
0
Number of Aerators
0
BLACK & VEATCH ACTIVATED SLUDGE MODEL
ADG
GVD
OWNER Yakima
PLANT WWTP
PROJ NO. Complete Denitrification
WORK
MM 2024 Del Monte
5 basins in service
COMPUTED BY
DATE 9/14/2004
B&V FILE NO.
CHECKED BY
DATE 9/14/2004
INPUT TO CMAS MODEL
_
Tot Vol, cu ft
702,000 alpha -
0.6 Elevation, ft
1065
Anoxic Vol,(%)
10 beta
0.95 Station Pres,psi
14.15
Tot det Tim, hr
Min DO @Pk, mg/I
1 SW depth,ft
26
Anox Det Tim,hr
Min DO @Ave,mg/l
2 Diffus depth, ft
25
Inf BOD, mg/I
156 Std Cs20, mg/l
11.10
Inf TSS, mg/I
108 Amb Cs, mg/I
10.45 FINAL CLARIFIERS
Eff TSS, mg/I
15 SRT, days
8 No. of Clarifiers
2
NonBVSS
0.30 RAS TSS, mg/1
8,000 Clarifier SWD, ft
15
VSS/TSS
0.82 MLSS, mgll
Dia. of Clarifier, ft
140
Inf Ma, mg/I
21 Inf TKN, mg/I
20 Design SOR, gpd/sf
Flow, mgd
16.3 NO3-N, mg/I
Floc Well HRT, min
MLSS Rec Q, mgd
32.6 Min Eff Alk, mg/I
100 Floc Well SWD, ft
Carb Peak Factor
1.3 Inf alk, mg/I
270 No. of Floc Turbines
Nitr Peak Factor
1.3 Temp, C
20.78 Max G, 1/sec
Diffuser type (Gen. Fine =1, Coarse = 3, Stat. Tube = 4)
1
STEADY STATE OPERATING CHARACTERISTICS
FINAL CLARIFIERS
Tot Det time, hr
7.73 Tot Vol, cf
702000
ClarifierTot. Area, sf
30787
Oxic Det time,hr
6.96 Oxic Vol, cf
631800
SOR, gpd/sf
529
Anox Det Time,hr
0.77 Anoxi Vol, cf
70200
Dia. of Clarifier, ft
140
CALC. SRT
8.89
SLR(100%RAS),ppd/sf
24
SRT, days
8.00 BOD Load, ppd/kcf
34
Clarifier HRT, hrs
5.1
Req SRT, days
6.32
Floc Well Diem., ft #DIV/0I
Min SRT, days
3.33
Turbine Power,bhp/unit #DIV/0!
CARBONACEOUS
NITROGENOUS
COMBINED
Unmet Frac, mg/I
1.26
Eff SNH, mg/I
0.02
Unmet Frac, mg/I
1.26
Act Mass, mg/I
747
Act Mass,mg/I
68
Act Mass, mg/I
815
End Mass, mg/l
606
End Mass, mg/I
50
End Mass, mg/I
655
MLVSS, mg/I
2012
MLVSS, mg/I
118
MLVSS, mg/I
2130
MLSS, mg/l
2630
MLSS, mg/I
130
MLSS, mg/I
2760
F/Mv Ratio
0.24
F/Mv Ratio
0.23
Eff BOD, mg/1
4.7
Eff BOD, mg/I
4.8
WAS, ppd
12360
WAS, ppd
711
WAS, ppd
13071
WVS, ppd
9456
WVS, ppd
633
WVS, ppd
10089
WMa, ppd
3510
WMa, ppd
351
WMa, ppd
3860
AvgdO/dt, mg/l/h
28.8
AvgdO/dt, mg/l/h
10.3
AvgdO/dt, mg/I/h
38.1
Pk dO/dt, mg/l/h
32.3
Pk dO/dt, mg/I/h
13.2
Pk dO/dt, mg/I/h
42.3
DENITRIFICATION
Pk Kla 20, I/h
7.8
Ave ANXdO/dt,mg/I/h
132.4
Ave KLa 20,I/h
7.9
Ave Den AOS, pph
169
Alk Req, mg/I
0
Ave TAOR, pph
1500
Ave Anox AOR, pph
557
Eff NO3, mg/l
4.2
Ave SOTR, pph
3460
Eff Alk, mg/I
203
Pk TAOR,pph
1668
Pk ANOdO/dt,mg/I/h
166.9
Eff TKN, mg/I
0.9
Pk SOTR, pph
3417
Pk Den AOS, pph
266
N in WAS, mg/I
4.38
RAS Flow, mgd
8.2
Pk Anox AOR, pph
719
Min N Req, mg/1
5.31
WAS Flow, gpd
195909
BLACK & VEATCH ACTIVATED SLUDGE MODEL
OWNER Yakima COMPUTED BY
PLANT WWTP DATE
PROJ NO, Complete Denitrification B&V FILE NO.
WORK CHECKED BY
MM 2024 Del Monte DATE
5 basins in service
ADG
9/14/2004
GVD
9/14/2004
AERATION EQUIPMENT DESIGN
INPUT TO AERATION MODEL
DIFFUSER SYSTEM
Design SOTR, pph
3460
Lateral Spacing, ft
3
Diffuser Area, sf
0.410
Airflow per diffuser, scfm/diff
1.5
Min Air for Mixing, scfm/kcf (Fine = 15, Coarse = 20)
15
Number of Diffuser
9500
BLOWER SYSTEM
Peak Ambient Temp, F
110
Average Ambient Temp, F
65
Blower Efficiency,%
55
Headloss thru Diffuser (Fine = 1, Coarse = 0.5)
1
MECHANICAL AERATION
Design SOTR, pph
0
Transfer Efficiency, lbs 02/hr/bhp
(Low Speed: 3.2 for <75 HP; 3.0 for 75<HP<100; 2.8 for HP>100);(High Speed = 2.0)
Aerator Size, nhp/unit
Minimum mixing power, bhp/kcf
0.75
Motor Service Factor, bhp/nhp
0.87
OUTPUT FROM AERATION MODEL
DIFFUSER SYSTEM
Process Airflow,scfm
6692
Minimum Air for Mixing, scfm
9477
Design Airflow (without 10% safety factor), scfm
9477
Oxygen Transfer Efficiency (OTE), % (OTE = 0 for Mixing limited Cond.)
0.0
Number of Diffusers
9500
Airflow per diffuser, scfm/diff
1.0
Tank Area/Diffuser Area (At/Ad)
6.2
Diffuser Density, sq ft/diff
2.6
BLOWER SYSTEM
Blower HP at Peak Temperature, whp
784
Blower HP at Ave. Temperature, whp
722
Blower HP for Mixing at Ave. Temperature, whp
722
MECHANICAL AERATION
Total Aerator Process Power, bhp
0
Total Aerator Mixing Power, bhp
0
Design Aerator Power, bhp
0
Number of Aerators
0
2024 MM
0 045
Raw Influent •
mg L PPd
FlOw 15.50
000 303 48.870
TSS 324 41682
NH3-N 33 4,229
Pnmary Clarifier Influent
mgIL pad
Flow 16.05
DOD 398 51,974
T55 363 48,519
N143 -N 32 4,234
1Mm4y CIanller Calve nt
neon PPd
How 15.57
800 250 33,203
125 178 23,774
6F1349 32 4,214
5191esir99mz
mg& ppd
Flow 0.50
000 288 1200
T55 894 808
NH3-6
FC Sludge
mg.L1_ 696
Flow 0.047
800 0944 3.090
T35 14071 5,829
NH3-6 12 4.7
3999
5828
4.5
Ptlmary C4rltler
900%Ram 30
TS5%Rent i,.su;1;
4.14494
Primary Dludge a 6054 TFC Sludge
0158. ppd
Flow 0.074
DOD 30,246 15,711
755 40,000 24,745
19183-N 32 20
Del Menlo Inllwnt
mgll ppd
How 0.;3
800 4210 11.010
785 461 1,209
NH3-6 4 10
Total PC Effluent
n,8. PPd
ppolm0d
Flow 14.30
900 330 44.973
T55 104 25.043
8193-9 31 4.224
2752
1536
259
tlb p0dlkr
1091 4.00
9013 330 12,394
T85 184 8.917
8143-19 31 1,187
Aemilon -
Basln
1
'Trickling Filler Int Omni_
1698. p
Flow 1180
800 330 32,479
T3.5 164 16,120
NH3-8 31 3.057
Aeration Basin 10114enl
,n9n_ ppd
Flow 10.30
00D 177 24,087
TSS 108 14,987
892-81 17 2,348
Bate Actie4140 Sludge
m•fl
Flow (mgdO 0.31
140866 0
795 5000 13,030
5 Wslna
Trickling
Filler
'Trickling Filler Clar 811
0.846JL PP'1
Floe 11.80
000 110 11.693
T50 79 7,770
971344 12 1.181
CMAS
150 21164
109 14,687
21 2923 Ma
Trickling Filter Clar Sludge
50% TI. 5100ge
m4.4_ppd
1
o DAF
How (mgd,
0.09
0.045
m90
000
10032
7.705
3098
ppd
0.30 996
'156
15000
11,055
5820
ppd
NH3-8112
9
4.5
ppd
18008 076
%cane
15
_
total 5159100 - 43.40.1 ppc
BLACK & VEATCH ACTIVATED SLUDGE MODEL
OWNER Yakima
PLANT WWTP
PROJ NO.
WORK
MM 2024 Del Monte
5 basins in service
COMPUTED BY ADG
DATE 9/14/2004
B&V FILE NO.
CHECKED BY GVD
DATE 9/14/2004
INPUT TO CMAS MODEL
Tot Vol, cu ft
Anoxic Vol,(%)
Tot del Tim, hr
Anox Det Tim,hr
Inf BOD, mg/I
Inf TSS, mg/I
Eff TSS, mg/I
NonBVSS
VSS/TSS
Inf Ma, mg/l
Flow, mgd
MLSS Rec Q, mgd
Carb Peak Factor
Nitr Peak Factor
702,000 alpha
beta
Min DO @Pk, mg/I
Min DO @Ave,mg/I
156 Std Cs20, mg/I
108 Amb Cs, mg/I
15 SRT, days
0.30 RAS TSS, mg/I
0.82 MLSS, mg/l
21 Inf TKN, mg/I
16.3 NO3-N, mg/I
Min Eff Alk, mg/I
1.3 Inf alk, mg/1
1.3 Temp, C
0.65 Elevation, ft 1065
0.95 Station Pres,psi 14.15
1 SW depth,ft 26
2 Diffus depth, ft 25
11.10
10.45 FINAL CLARIFIERS
8 No. of Clarifiers 2
7,500 Clarifier SWD, ft 15
Dia. of Clarifier, ft 140
20 Design SOR, gpd/sf
Floc Well HRT, min
100 Floc Well SWD, ft
270 No. of Floc Turbines
20.78 Max G, 1/sec
Diffuser type (Gen. Fine =1, Coarse = 3, Stat. Tube = 4)
1
STEADY STATE OPERATING CHARACTERISTICS
FINAL CLARIFIERS
Tot Det time, hr
Oxic Det time,hr
Anox Det Time,hr
CALC. SRT
SRT, days
Req SRT, days
Min SRT, days
7.73 Tot Vol, cf
7.73 Oxic Vol, cf
0.00 Anoxi Vol, cf
8.89
8.00 BOD Load, ppd/kcf
5.69
3.00
702000
702000
0
30
ClarifierTot. Area, sf 30787
SOR, gpd/sf 529
Dia. of Clarifier, ft 140
SLR(100%RAS),ppd/sf 24
Clarifier HRT, hrs 5.1
Floc Well Diam., ft #DIV/0!
Turbine Power,bhp/unit #DIV/01
CARBONACEOUS
NITROGENOUS
COMBINED
Unmet Frac, mg/I
Act Mass, mg/I
End Mass, mg/I
MLVSS, mg/l
MLSS, mg/I
F/Mv Ratio
Eff BOD, mg/l
WAS, ppd
WVS, ppd
WMa, ppd
AvgdO/dt, mg/l/h
Pk dO/dt, mg/l/h
1.26
747
606
2012
2630
0.24
4.7
12360
9456
3510
28.8
32.3
Eff SNH, mg/I
Act Mass,mg/I
End Mass, mg/I
MLVSS, mg/I
MLSS, mg/I
WAS, ppd
WVS, ppd
WMa, ppd
AvgdO/dt, mg/l/h
Pk dO/dt, mg/l/h
Alk Req, mg/I
Eff NO3, mg/l
Eff Alk, mg/I
Eff TKN, mg/I
N in WAS, mg/I
Min N Req, mg/I
0.02
63
51
114
125
685
609
324
9.3
12.0
0
14.7
165
0.9
4.36
5.29
Unmet Frac, mg/I 1.26
Act Mass, mg/I 810
End Mass, mg/I 657
MLVSS, mg/I 2126
MLSS, mg/I 2755
F/Mv Ratio 0.23
Eff BOD, mg/l 4.8
WAS, ppd 13045
WVS, ppd 10065
WMa, ppd 3833
AvgdO/dt, mg/l/h 38.2
Pk dO/dt, mg/l/h 44.3
Pk Kla 20, l/h 7.5
Ave KLa 20,1/h 7.3
Ave TAOR, pph 1673
Ave SOTR, pph 3562
Pk TAOR,pph 1938
Pk SOTR, pph 3664
RAS Flow, mgd 9.1
WAS Flow, gpd 208549
DENITRIFICATION
Ave ANXdO/dt,mg/l/h
Ave Den AOS, pph
Ave Anox AOR, pph
Pk ANOdO/dt,mg/l/h
Pk Den AOS, pph
Pk Anox AOR, pph
0.0
0
0
0.0
0
0
BLACK & VEATCH ACTIVATED SLUDGE MODEL
OWNER Yakima
PLANT WWTP
PROJ NO.
WORK
MM 2024 Del Monte
5 basins in service
COMPUTED BY ADG
DATE 9/14/2004
B&V FILE NO.
CHECKED BY GVD
DATE 9/14/2004
AERATION EQUIPMENT DESIGN
INPUT TO AERATION MODEL
DIFFUSER SYSTEM
Design SOTR, pph 3664
Lateral Spacing, ft 3
Diffuser Area, sf 0.410
Airflow per diffuser, scfm/diff 1.5
Min Air for Mixing, scfm/kcf (Fine = 15, Coarse = 20) 15
Number of Diffuser 9500
BLOWER SYSTEM
Peak Ambient Temp, F 110
Average Ambient Temp, F 65
Blower Efficiency,% 55
Headloss thru Diffuser (Fine = 1, Coarse = 0.5) 1
MECHANICAL AERATION
Design SOTR, pph
Transfer Efficiency, lbs O2/hr/bhp
(Low Speed: 3.2 for <75 HP; 3.0 for 75<HP<100; 2.8 for HP>100);(High Speed = 2.0)
Aerator Size, nhplunit
Minimum mixing power, bhp/kcf
Motor Service Factor, bhp/nhp
0
0.75
0.87
OUTPUT FROM AERATION MODEL
DIFFUSER SYSTEM
Process Airflow,scfm 7184
Minimum Air for Mixing, scfm 10530
Design Airflow (without 10% safety factor), scfm 10530
Oxygen Transfer Efficiency (OTE), % (OTE = 0 for Mixing limited Cond.) 0.0
Number of Diffusers 9500
Airflow per diffuser, scfm/diff 1.1
Tank Area/Diffuser Area (At/Ad) 6.9
Diffuser Density, sq ft/diff 2.8
BLOWER SYSTEM
Blower HP at Peak Temperature, whp 871
Blower HP at Ave. Temperature, whp 803
Blower HP for Mixing at Ave. Temperature, whp 803
MECHANICAL AERATION
Total Aerator Process Power, bhp 0
Total Aerator Mixing Power, bhp 0
Design Aerator Power, bhp 0
Number of Aerators 0
Table 5-9
Current DAFT Loading and Theoretical Capacity
Combined WAS and
Trickling Filter Solids
(pT d)
SLR'
(1b/hr/s1)
Current Operation
Annual Average
7,7003
8,900)
0.4
0.5
Maximum Month
2024 Operation with TF solids2
Annual Average
17,000
0.9
Annual Average (24 hour)
17,000
0.4
Maximum Month
25,000
1.34
Maximum Month (24 hour)
25,000
0.7
Theoretical DAFT Capacity
Without polymer addition
8,000
0.4
Without polymer addition (24 hour)
16,000
0.4
With polymer addition
19,000
1.0
With polymer addition (24 hour)
38,000
1.0
SLR based on 12 hr/day, 7 day/week operating schedule, unless otherwise noted.
2Assumes 100 percent of trickling filter solids are thickened through DAFT.
3Cturent quantities do not always include trickling filter solids.
4Exceeds recommended SLR,
Table 5-11
Existing Digester Tankage Capacity
2004
2024
Average
Annual
Maximum
Month
Average
Annual
Maximum
Month
WAS, ppd
5,500
7,400
7,500
13,000
Primary solids, ppd
9,100
12,500
13,000
19,000
Trickling Filter solids, ppd
6,300
11,200
9,500
12,000
Total Solids, ppd
20,900
31,100
30,000
44,000
Combined Solids, Vol
4.1
4.1
4.1
4.1
Total Solids, gpd
61,100
91,000
88,000
129,000
Primary HRT, days
27
18
19
132
Secondary IIRT, days
11
7
7
5
1Solids concentration based on treating 50 percent of the trickling filter solids through the DAFT
and 50 percent through the primary clarifier.
2Primary digester capacity does not provide 15 day detention to meet 40 CFR Part 503
requirements for Class B solids.
25,000
20,000
Q 15,000
0
xi
10,000
W
CLI
H
5,000
0
0
Figure 5-6. Trickling Filter Loading Rate
5,000
10,000
15,000 20,000
TF Influent BOD (ppd)
25,000
30,000
35,000
♦ 2001-2002 Baseline • 2001 Canning • 2002 Canning
•
••
•
•
•
•
♦
•
♦ •
•
•
•
5,000
10,000
15,000 20,000
TF Influent BOD (ppd)
25,000
30,000
35,000
BLACK & VEATCH ACTIVATED SLUDGE MODEL
ADG
GVD
9/22/04
OWNER Yakima
PLANT WWTP
PROJ NO.
WORK No TF Clarifier
MM 2009 Del Monte
4 basins in service
COMPUTED BY
DATE 9/22/2004
B&V FILE NO.
CHECKED BY
DATE
INPUT TO CMAS MODEL
Tot Vol, cu ft
561,600 alpha
0.65 Elevation, ft
1065
Anoxic Vol,(%)
beta
0.95 Station Pres,psi
14.15
Tot det Tim, hr
Min DO @Pk, mg/1
1 SW depth,ft
26
Anox Det Tim,hr
Min DO @Ave,mg/l
2 Diffus depth, ft
25
Inf BOD, mg/I
172 Std Cs20, mg/I
11.10
IN TSS, mg/I
167 Amb Cs, mg/I
10.45 FINAL CLARIFIERS
Eff TSS, mg/l
15 SRT, days
8 No. of Clarifiers
2
NonBVSS
0.30 RAS TSS, mg/I
7,500 Clarifier SWD, ft
15
VSS/TSS
0.82 MLSS, mg/l
Dia. of Clarifier, ft
140
Inf Ma, mg/I
40 Inf TKN, mg/I
20 Design SOR, gpd/sf
Flow, mgd
13.1 NO3-N, mg/I
Floc Well HRT, min
MLSS Rec Q, mgd
Min Eff Alk, mg/I
100 Floc Well SWD, ft
Carb Peak Factor
1.3 Inf alk, mg/1
270 No. of Floc Turbines
Nitr Peak Factor
1.3 Temp, C
20.78 Max G, 1/sec
Diffuser type (Gen. Fine =1, Coarse = 3, Stat. Tube = 4)
1
STEADY STATE OPERATING CHARACTERISTICS
FINAL CLARIFIERS
Tot Det time, hr
7.68 Tot Vol, cf
561600
ClarifierTot. Area, sf
30787
Oxic Det time,hr
7.68 Oxic Vol, cf
561600
SOR, gpd/sf
426
Anox Det Time,hr
0.00 Anoxi Vol, cf
0
Dia. of Clarifier, ft
140
CALC. SRT
8.89
SLR(100%RAS),ppd/sf
26
SRT, days
8.00 BOD Load, ppd/kcf
34
Clarifier HRT, hrs
6.3
Req SRT, days
5.69
Floc Well Diam., ft #DIV/0!
Min SRT, days
3.00
Turbine Power,bhp/unit #DIV/0!
CARBONACEOUS
NITROGENOUS
COMBINED
Unmet Frac, mg/I
1.40
Eff SNH, mg/I
0.02
Unmet Frac, mg/I
1.40
Act Mass, mg/I
912
Act Mass,mg/I
63
Act Mass, mg/I
975
End Mass, mg/I
739
End Mass, mg/l
51
End Mass, mg/I
791
MLVSS, mg/I
2678
MLVSS, mg/I
114
MLVSS, mg/I
2792
MLSS, mg/I
3594
MLSS, mg/I
126
MLSS, mg/I
3720
F/Mv Ratio
0.20
F/Mv Ratio
0.19
Eff BOD, mg/1
4.4
Eff BOD, mg/l
4.5
WAS, ppd
14097
WAS, ppd
551
WAS, ppd
14648
WVS, ppd
10503
WVS, ppd
492
WVS, ppd
10995
WMa, ppd
3577
WMa, ppd
263
WMa, ppd
3840
AvgdO/dt, mg/l/h
33.9
AvgdO/dt, mg/l/h
8.8
AvgdO/dt, mg/I/h
42.8
Pk dO/dt, mg/l/h
37.8
Pk dO/dt, mg/l/h
11.3
Pk dO/dt, mg/I/h
49.0
DENITRIFICATION
Pk Kla 20, I/h
8.4
Ave ANXdO/dt,mg/I/h
0.0
Ave KLa 20,1/h
8.2
Ave Den AOS, pph
0
Alk Req, mg/I
0
Ave TAOR, pph
1498
Ave Anox AOR, pph
0
Eff NO3, mg/1
13.7
Ave SOTR, pph
3190
Eff Alk, mg/I
172
Pk TAOR,pph
1718
Pk ANOdO/dt,mg/I/h
0.0
Eff TKN, mg/l
0.8
Pk SOTR, pph
3249
Pk Den AOS, pph
0
N in WAS, mg/l
5.43
RAS Flow, mgd
12.4
Pk Anox AOR, pph
0
Min N Req, mg/1
6.26
WAS Flow, gpd
234189
AERATION EQUIPMENT DESIGN
INPUT TO AERATION MODEL
DIFFUSER SYSTEM
Design SOTR, pph
3249
Lateral Spacing, ft
4
Diffuser Area, sf
0.410
Airflow per diffuser, scfm/diff
3.5
Min Air for Mixing, scfm/kcf (Fine = 15, Coarse = 20)
15
Number of Diffuser
BLOWER SYSTEM
Peak Ambient Temp, F
110
Average Ambient Temp, F
65
Blower Efficiency,%
55
Headloss thru Diffuser (Fine = 1, Coarse = 0.5)
1
MECHANICAL AERATION
Design SOTR, pph
0
Transfer Efficiency, lbs 02/hr/bhp
(Low Speed: 3.2 for <75 HP; 3.0 for 75<HP<100; 2.8 for HP>100);(High Speed = 2.0)
Aerator Size, nhp/unit
Minimum mixing power, bhp/kcf
0.75
Motor Service Factor, bhp/nhp
0.87
OUTPUT FROM AERATION MODEL
DIFFUSER SYSTEM
Process Airflow,scfm
8263
Minimum Air for Mixing, scfm
8424
Design Airflow (without 10% safety factor), scfm
8424
Oxygen Transfer Efficiency (OTE), % (OTE = 0 for Mixing limited Cond.)
0.0
Number of Diffusers
2407
Airflow per diffuser, scfm/diff
3.5
Tank Area/Diffuser Area (At/Ad)
21.9
Diffuser Density, sq ft/diff
9.0
BLOWER SYSTEM
Blower HP at Peak Temperature, whp
697
Blower HP at Ave. Temperature, whp
642
Blower HP for Mixing at Ave. Temperature, whp
642
MECHANICAL AERATION
Total Aerator Process Power, bhp
0
Total Aerator Mixing Power, bhp
0
Design Aerator Power, bhp
0
Number of Aerators
0
BLACK & VEATCH ACTIVATED SLUDGE MODEL
ADG
GVD
OWNER Yakima
PLANT WWTP
PROJ NO.
WORK
MM 2019 Del Monte
4 basins in service
COMPUTED BY
DATE 9/14/2004
B&V FILE NO.
CHECKED BY
DATE 9/14/2004
INPUT TO CMAS MODEL
Tot Vol, cu ft
561,600 alpha
0.6 Elevation, ft
1065
Anoxic Vol,(%)
beta
0.95 Station Pres,psi
14.15
Tot det Tim, hr
Min DO @Pk, mg/I
1 SW depth,ft
26
Anox Det Tim,hr
Min DO @Ave,mg/I
2 Diffus depth, ft
22.8
Inf BOD, mg/I
144 Std Cs20, mg/I
11.00
Inf TSS, mg/I
102 Amb Cs, mg/I
10.35 FINAL CLARIFIERS
Eff TSS, mg/I
15 SRT, days
8 No. of Clarifiers
2
NonBVSS
0.30 RAS TSS, mg/I
8,000 Clarifier SWD, ft
15
VSS/TSS
0.82 MLSS, mg/I
Dia. of Clarifier, ft
140
Inf Ma, mg/I
24 Inf TKN, mg/I
20 Design SOR, gpd/sf
Flow, mgd
15.0 NO3-N, mg/I
Floc Well HRT, min
MLSS Rec Q, mgd
Min Eff Alk, mg/I
100 Floc Well SWD, ft
Carb Peak Factor
1.3 Inf alk, mg/I
270 No. of Hoc Turbines
Nitr Peak Factor
1.3 Temp, C
20.78 Max G, 1/sec
Diffuser type (Gen. Fine =1, Coarse = 3, Stat. Tube = 4)
1
STEADY STATE OPERATING CHARACTERISTICS
FINAL CLARIFIERS
Tot Det time, hr
6.72 Tot Vol, cf
561600
ClarifierTot. Area, sf
30787
Oxic Det time,hr
6.72 Oxic Vol, cf
561600
SOR, gpd/sf
488
Anox Det Time,hr
0.00 Anoxi Vol, cf
0
Dia. of Clarifier, ft
140
CALC. SRT
8.89
SLR(100%RAS),ppd/sf
25
SRT, days
8.00 BOD Load, ppd/kcf
32
Clarifier HRT, hrs
5.5
Req SRT, days
5.69
Floc Well Diam., ft #DIV/0!
Min SRT, days
3.00
Turbine Power,bhp/unit #DIV/0!
CARBONACEOUS
NITROGENOUS
COMBINED
Unmet Frac, mg/I
1.34
Eff SNH, mg/l
0.02
Unmet Frac, mg/I
1.34
Act Mass, mg/I
819
Act Mass,mg/l
72
Act Mass, mg/I
891
End Mass, mg/I
664
End Mass, mg/I
59
End Mass, mg/I
723
MLVSS, mg/I
2200
MLVSS, mg/I
131
MLVSS, mg/I
2331
MLSS, mg/I
2873
MLSS, mg/I
144
MLSS, mg/l
3017
F/Mv Ratio
0.23
F/Mv Ratio
0.22
Eff BOD, mg/I
4.8
Eff BOD, mg/I
4.9
WAS, ppd
10705
WAS, ppd
631
WAS, ppd
11336
WVS, ppd
8197
WVS, ppd
561
WVS, ppd
8758
WMa, ppd
3051
WMa, ppd
297
WMa, ppd
3348
AvgdO/dt, mg/l/h
31.2
AvgdO/dt, mg/I/h
10.9
AvgdO/dt, mg/l/h
42.1
Pk dOldt, mg/I/h
34.9
Pk dO/dt, mg/l/h
13.9
Pk dO/dt, mg/l/h
48.9
DENITRIFICATION
Pk Kla 20,1/h
9.1
Ave ANXdO/dt,mg/l/h
0.0
Ave KLa 20,I/h
8.9
Ave Den AOS, pph
0
Alk Req, mg/I
0
Ave TAOR, pph
1476
Ave Anox AOR, pph
0
Eff NO3, mg/I
14.9
Ave SOTR, pph
3414
Eff Alk, mg/I
163
Pk TAOR,pph
1712
Pk ANOdO/dt,mg/l/h
0.0
Eff TKN, mg/I
0.9
Pk SOTR, pph
3510
Pk Den AOS, pph
0
N in WAS, mg/I
4.13
RAS Flow, mgd
8.8
Pk Anox AOR, pph
0
Min N Req, mg/I
5.07
WAS Flow, gpd
169901
BLACK & VEATCH ACTIVATED SLUDGE MODEL
OWNER Yakima COMPUTED BY
PLANT WWTP DATE
PROJ NO. B&V FILE NO.
WORK CHECKED BY
MM 2019 Del Monte DATE
4 basins in service
ADG
9/14/2004
GVD
9/14/2004
AERATION EQUIPMENT DESIGN
INPUT TO AERATION MODEL
DIFFUSER SYSTEM
Design SOTR, pph
3510
Lateral Spacing, ft
3
Diffuser Area, sf
0.410
Airflow per diffuser, scfm/diff
1.5
Min Air for Mixing, scfm/kcf (Fine = 15, Coarse = 20)
15
Number of Diffuser
7600
BLOWER SYSTEM
Peak Ambient Temp, F
100
Average Ambient Temp, F
65
Blower Efficiency,%
55
Headloss thru Diffuser (Fine = 1, Coarse = 0.5)
1
MECHANICAL AERATION
Design SOTR, pph
0
Transfer Efficiency, lbs 02/hr/bhp
(Low Speed: 3.2 for <75 HP; 3.0 for 75<HP<100; 2.8 for HP>100);(High Speed = 2.0)
Aerator Size, nhp/unit
Minimum mixing power, bhp/kcf
0.75
Motor Service Factor, bhp/nhp
0.87
OUTPUT FROM AERATION MODEL
DIFFUSER SYSTEM
Process Airflow,scfm
7633
Minimum Air for Mixing, scfm
8424
Design Airflow (without 10% safety factor), scfm
8424
Oxygen Transfer Efficiency (OTE), % (OTE = 0 for Mixing limited Cond.)
0.0
Number of Diffusers
7600
Airflow per diffuser, scfm/diff
1.1
Tank Area/Diffuser Area (At/Ad)
6.9
Diffuser Density, sq ft/diff
2.8
BLOWER SYSTEM
Blower HP at Peak Temperature, whp
639
Blower HP at Ave. Temperature, whp
599
Blower HP for Mixing at Ave. Temperature, whp
599
MECHANICAL AERATION
Total Aerator Process Power, bhp
0
Total Aerator Mixing Power, bhp
0
Design Aerator Power, bhp
0
Number of Aerators
0
Flow
BOD
TSS
NH3-N
2019 MM
0.046
Raw Influent
mgIL ppd
Flow
BOD
TSS
NH3-N
14.20
357 42,237
319 37,737
32 3,810
Primary Clarifier Influent
mgIL ppd
Flow
BOD
TSS
NH3-N
14.75
385
361
31
47,376
44,340
3,815
Primary Clarifier Effluent
mgIL ppd
Flow
BOD
TSS
NH3-N
14.68
248 30,321
177 21,727
31 3,797
Sldestreams
mg/L ppd
Flow 0.50
BOD 288 1200
TSS 194 808
TFC Sludge
mgIL ppd
Flow 0.046
BOD 10267
TSS 15105
NH3-N 12
3,939
5,795
4.5
3939
5795
4.5
Primary Clarifier
BOD % Rem 36
TSS % Rem 51
Sludge TSS % 4
Del Monte Influent
mgIL ppd
Flow
BOD
TSS
NH3-N
0.33
4218 11,610
461 1,269
4 10
Total PC Effluent
mgIL ppd ppd/mgd
15.01
335 41,931 2794
184 22,996 1532
30 3,807 254
90 ppd/kcf
Primary Sludge + 50% TFC Sludge
mtIL ..c1
Flow
BOD
TSS
NH3-N
0.068
30,169 17,055
40,000 22,613
31 18
By -Pass
mgll. ppd
Flow 3.26
BOD 335
TSS 184
9,103
4,992
NH3-N 30 826
Aeration
Basin
Trickling Filter Influent
mg/L ppd
Flow
BOD
TSS
11.75
335 32,828
184 18,003
NH3-N 30 2,980
Aeration Basin Influent
mgIL ppd
Flow
BOD
TSS
NH3-N
15.01
167 20,921
102 12,719
16 2,002
Waste Activated Sludge
mgIL ppd
Flow (mgd; 0.27
%conc 0.5
TSS 5000 11,336
Trickling
Filter
144
102
24
Trickling Filter Clar Eff
mgIL ppd
Flow 11.75
BOD 121 11,818
TSS 79 7,727
NH3-N 12 1,176
CMAS
17966
12,719
2955
Ma
Trickling Filter Clar Sludge
mgIL ppd
50% TF Sludge
To DAF
Flow (mgd;
0.09
0.045
mgd
BOD
10197
7,879
3940
ppd
0.32
mgd
TSS
15000
11,590
5795
ppd
NH3-N
12
9
4.5
ppd
17131
ppd
%conc
1.5
Total Sludge = 39,744 ppd
BLACK & VEATCH ACTIVATED SLUDGE MODEL
ADG
GVD
OWNER Yakima
PLANT WWTP
PROJ NO. Complete Denitrification
WORK
MM 2019 Del Monte
4 basins in service
COMPUTED BY
DATE 9/14/2004
B&V FILE NO.
CHECKED BY
DATE 9/14/2004
INPUT TO CMAS MODEL
Tot Vol, cu ft
561,600 alpha
0.6 Elevation, ft
1065
Anoxic Vol,(%)
12.5 beta
0.95 Station Pres,psi
14.15
Tot det Tim, hr
Min DO @Pk, mg/I
1 SW depth,ft
26
Anox Det Tim,hr
Min DO @Ave,mg/I
2 Diffus depth, ft
22.8
Inf BOD, mg/I
144 Std Cs20, mg/l
11.00
Inf TSS, mg/I
102 Amb Cs, mg/I
10.35 FINAL CLARIFIERS
Eff TSS, mg/I
15 SRT, days
8 No. of Clarifiers
2
NonBVSS
0.30 RAS TSS, mg/I
8,000 Clarifier SWD, ft
15
VSS/TSS
0.82 MLSS, mg/I
Dia. of Clarifier, ft
140
Inf Ma, mg/I
24 lnf TKN, mg/I
20 Design SOR, gpd/sf
Flow, mgd
15.0 NO3-N, mg/I
Floc Well HRT, min
MLSS Rec Q, mgd
30 Min Eff Alk, mg/I
100 Floc Well SWD, ft
Carb Peak Factor
1.3 Inf alk, mg/I
270 No. of Floc Turbines
Nitr Peak Factor
1.3 Temp, C
20.78 Max G, 1/sec
Diffuser type (Gen. Fine =1, Coarse = 3, Stat. Tube = 4)
1
STEADY STATE OPERATING CHARACTERISTICS
FINAL CLARIFIERS
Tot Det time, hr
6.72 Tot Vol, cf
561600
ClarifierTot. Area, sf
30787
Oxic Det time,hr
5.88 Oxic Vol, cf
491400
SOR, gpd/sf
488
Anox Det Time,hr
0.84 Anoxi Vol, cf
70200
Dia. of Clarifier, ft
140
CALC. SRT
8.89
SLR(100%RAS),ppd/sf
25
SRT, days
8.00 BOD Load, ppd/kcf
37
Clarifier HRT, hrs
5.5
Req SRT, days
6.50
Floc Well Diann., ft #DIV/0!
Min SRT, days
3.43
Turbine Power,bhp/unit #DIV/0!
CARBONACEOUS
NITROGENOUS
COMBINED
Unmet Frac, mg/I
1.34
Eff SNH, mg/l
0.03
Unmet Frac, mg/I
1.34
Act Mass, mg/1
819
Act Mass,mg/l
80
Act Mass, mg/1
899
End Mass, mg/I
664
End Mass, mg/I
57
End Mass, mg/I
721
MLVSS, mg/I
2200
MLVSS, mg/I
137
MLVSS, mg/I
2337
MLSS, mg/I
2873
MLSS, mg/I
151
MLSS, mg/I
3024
F/Mv Ratio
0.23
F/Mv Ratio
0.22
Eff BOD, mg/1
4.8
Eff BOD, mg/l
4.9
WAS, ppd
10705
WAS, ppd
662
WAS, ppd
11367
WVS, ppd
8197
WVS, ppd
588
WVS, ppd
8785
WMa, ppd
3051
WMa, ppd
329
WMa, ppd
3380
AvgdO/dt, mg/l/h
31.2
AvgdO/dt, mg/l/h
12.3
AvgdO/dt, mg/l/h
42.8
Pk dO/dt, mg/I/h
34.9
Pk dO/dt, mg/I/h
15.8
Pk dO/dt, mg/I/h
47.6
DENITRIFICATION
Pk Kla 20,1/h
8.9
Ave ANXdO/dt,mg/l/h
116.8
Ave KLa 20,1/h
9.0
Ave Den AOS, pph
160
Alk Req, mg/I
0
Ave TAOR, pph
1313
Ave Anox AOR, pph
491
Eff NO3, mg/I
4.2
Ave SOTR, pph
3036
Eff Alk, mg/I
202
Pk TAOR,pph
1459
Pk ANOdO/dt,mg/l/h
146.1
Eff TKN, mg/I
0.9
Pk SOTR, pph
2991
Pk Den AOS, pph
249
N in WAS, mg/I
4.16
RAS Flow, mgd
8.8
Pk Anox AOR, pph
629
Min N Req, mg/I
5.10
WAS Flow, gpd
170365
BLACK & VEATCH ACTIVATED SLUDGE MODEL
OWNER Yakima COMPUTED BY
PLANT W W TP DATE
PROJ NO. Complete Denitrification B&V FILE NO.
WORK CHECKED BY
MM 2019 Del Monte DATE
4 basins in service
ADG
9/14/2004
GVD
9/14/2004
AERATION EQUIPMENT DESIGN
INPUT TO AERATION MODEL
DIFFUSER SYSTEM
Design SOTR, pph
3036
Lateral Spacing, ft
3
Diffuser Area, sf
0.410
Airflow per diffuser, scfm/diff
1.5
Min Air for Mixing, scfm/kcf (Fine = 15, Coarse = 20)
15
Number of Diffuser
7600
BLOWER SYSTEM
Peak Ambient Temp, F
100
Average Ambient Temp, F
65
Blower Efficiency,%
55
Headloss thru Diffuser (Fine = 1, Coarse = 0.5)
1
MECHANICAL AERATION
Design SOTR, pph
0
Transfer Efficiency, lbs 02/hr/bhp
(Low Speed: 3.2 for <75 HP; 3.0 for 75<HP<100; 2.8 for HP>100);(High Speed = 2.0)
Aerator Size, nhp/unit
Minimum mixing power, bhp/kcf
0.75
Motor Service Factor, bhp/nhp
0.87
OUTPUT FROM AERATION MODEL
DIFFUSER SYSTEM
Process Airflow,scfm
6421
Minimum Air for Mixing, scfm
7371
Design Airflow (without 10% safety factor), scfm
7371
Oxygen Transfer Efficiency (OTE), % (OTE = 0 for Mixing limited Cond.)
0.0
Number of Diffusers
7600
Airflow per diffuser, scfm/diff
1.0
Tank Area/Diffuser Area (At/Ad)
6.1
Diffuser Density, sq ft/diff
2.5
BLOWER SYSTEM
Blower HP at Peak Temperature, whp
559
Blower HP at Ave. Temperature, whp
524
Blower HP for Mixing at Ave. Temperature, whp
524
MECHANICAL AERATION
Total Aerator Process Power, bhp
0
Total Aerator Mixing Power, bhp
0
Design Aerator Power, bhp
0
Number of Aerators
0
BLACK & VEATCH ACTIVATED SLUDGE MODEL
ADG
GVD
OWNER Yakima
PLANT WWTP
PROJ NO. Complete Denitrification
WORK
MM 2024 Del Monte
5 basins in service
COMPUTED BY
DATE 9/14/2004
B&V FILE NO.
CHECKED BY
DATE 9/14/2004
INPUT TO CMAS MODEL
Tot Vol, cu ft
702,000 alpha
0.6 Elevation, ft
1065
Anoxic Vol,(%)
10 beta
0.95 Station Pres,psi
14.15
Tot det Tim, hr
Min DO @Pk, mg/l
1 SW depth,ft
26
Anox Det Tim,hr
Min DO @Ave,mg/I
2 Diffus depth, ft
25
Inf BOD, mg/I
156 Std Cs20, mg/1
11.10
Inf TSS, mg/I
108 Amb Cs, mg/I
10.45 FINAL CLARIFIERS
Eff TSS, mg/I
15 SRT, days
8 No. of Clarifiers
2
NonBVSS
0.30 RAS TSS, mg/I
8,000 Clarifier SWD, ft
15
VSS/TSS
0.82 MLSS, mg/I
Dia. of Clarifier, ft
140
Inf Ma, mg/I
21 Inf TKN, mg/1
20 Design SOR, gpd/sf
Flow, mgd
16.3 NO3-N, mg/I
Floc Well HRT, min
MLSS Rec Q, mgd
32.6 Min Eff Alk, mg/I
100 Floc Well SWD, ft
Carb Peak Factor
1.3 Inf alk, mg/I
270 No. of Floc Turbines
Nitr Peak Factor
1.3 Temp, C
20.78 Max G, 1/sec
Diffuser type (Gen. Fine =1, Coarse = 3, Stat. Tube = 4)
1
STEADY STATE OPERATING CHARACTERISTICS
FINAL CLARIFIERS
Tot Det time, hr
7.73 Tot Vol, cf
702000
ClarifierTot. Area, sf
30787
Oxic Det time,hr
6.96 Oxic Vol, cf
631800
SOR, gpd/sf
529
Anox Det Time,hr
0.77 Anoxi Vol, cf
70200
Dia. of Clarifier, ft
140
CALC. SRT
8.89
SLR(100%RAS),ppd/sf
24
SRT, days
8.00 BOD Load, ppd/kcf
34
Clarifier HRT, hrs
5.1
Req SRT, days
6.32
Floc Well Diam., ft #DIV/0!
Min SRT, days
3.33
Turbine Power,bhp/unit #DIV/0!
CARBONACEOUS
NITROGENOUS
COMBINED
Unmet Frac, mg/I
1.26
Eff SNH, mg/l
0.02
Unmet Frac, mg/I
1.26
Act Mass, mg/I
747
Act Mass,mg/l
68
Act Mass, mg/I
815
End Mass, mg/I
606
End Mass, mg/I
50
End Mass, mg/I
655
MLVSS, mg/l
2012
MLVSS, mg/I
118
MLVSS, mg/l
2130
MLSS, mg/I
2630
MLSS, mg/1
130
MLSS, mg/I
2760
F/Mv Ratio
0.24
F/Mv Ratio
0.23
Eff BOD, mg/I
4.7
Eff BOD, mg/I
4.8
WAS, ppd
12360
WAS, ppd
711
WAS, ppd
13071
WVS, ppd
9456
WVS, ppd
633
WVS, ppd
10089
WMa, ppd
3510
WMa, ppd
351
WMa, ppd
3860
AvgdO/dt, mg/I/h
28.8
AvgdOldt, mg/l/h
10.3
AvgdO/dt, mg/l/h
38.1
Pk dO/dt, mg/I/h
32.3
Pk dO/dt, mg/l/h
13.2
Pk dO/dt, mg/I/h
42.3
DENITRIFICATION
Pk Kla 20, I/h
7.8
Ave ANXdO/dt,mg/I/h
132.4
Ave KLa 20,1/h
7.9
Ave Den AOS, pph
169
Alk Req, mg/I
0
Ave TAOR, pph
1500
Ave Anox AOR, pph
557
Eff NO3, mg/I
4.2
Ave SOTR, pph
3460
Eff Alk, mg/I
203
Pk TAOR,pph
1668
Pk ANOdO/dt,mg/I/h
166.9
Eff TKN, mg/I
0.9
Pk SOTR, pph
3417
Pk Den AOS, pph
266
N in WAS, mg/I
4.38
RAS Flow, mgd
8.2
Pk Anox AOR, pph
719
Min N Req, mg/I
5.31
WAS Flow, gpd
195909
BLACK & VEATCH ACTIVATED SLUDGE MODEL
OWNER Yakima COMPUTED BY
PLANT WWTP DATE
PROJ NO. Complete Denitrification B&V FILE NO.
WORK CHECKED BY
MM 2024 Del Monte DATE
5 basins in service
ADG
9/14/2004
GVD
9/14/2004
AERATION EQUIPMENT DESIGN
INPUT TO AERATION MODEL
DIFFUSER SYSTEM
Design SOTR, pph
3460
Lateral Spacing, ft
3
Diffuser Area, sf
0.410
Airflow per diffuser, scfm/diff
1.5
Min Air for Mixing, scfm/kcf (Fine = 15, Coarse = 20)
15
Number of Diffuser
9500
BLOWER SYSTEM
Peak Ambient Temp, F
110
Average Ambient Temp, F
65
Blower Efficiency,%
55
Headloss thru Diffuser (Fine = 1, Coarse = 0.5)
1
MECHANICAL AERATION
Design SOTR, pph
0
Transfer Efficiency, lbs 02/hr/bhp
(Low Speed: 3.2 for <75 HP; 3.0 for 75<HP<100; 2.8 for HP>100);(High Speed = 2.0)
Aerator Size, nhp/unit
Minimum mixing power, bhp/kcf
0.75
Motor Service Factor, bhp/nhp
0.87
OUTPUT FROM AERATION MODEL
DIFFUSER SYSTEM
Process Airflow,scfm
6692
Minimum Air for Mixing, scfm
9477
Design Airflow (without 10% safety factor), scfm
9477
Oxygen Transfer Efficiency (OTE), % (OTE = 0 for Mixing limited Cond.)
0.0
Number of Diffusers
9500
Airflow per diffuser, scfm/diff
1.0
Tank Area/Diffuser Area (At/Ad)
6.2
Diffuser Density, sq ft/diff
2.6
BLOWER SYSTEM
Blower HP at Peak Temperature, whp
784
Blower HP at Ave. Temperature, whp
722
Blower HP for Mixing at Ave. Temperature, whp
722
MECHANICAL AERATION
Total Aerator Process Power, bhp
0
Total Aerator Mixing Power, bhp
0
Design Aerator Power, bhp
0
Number of Aerators
0
2024 MM
0.045
Raw Influent
mglL ppd
Flow
BOD
TSS
NH3-N
15.50
363 46,876
324 41,882
33 4,229
Sidestreams
Primary Clarifier Influent
mgIL ppd
Flow
BOD
TSS
NH3-N
16.05
388
363
32
51,974
48,519
4,234
Primary Clarifier Effluent
mg/L ppd
Flow
BOD
TSS
NH3-N
15.97
250 33,263
178 23,774
32 4,214
mgIL ppd
How 0.50
BOD 288 1200
TSS 194 808
NH3-N
TFC Sludge
mg1L ppd
Flow
BOD
TSS
NH3-N
0.047
9944 3,898
14871 5,829
12 4.7
3898
5828
4.5
Primary
BOD % Rem
TSS % Rem
fudge TSS
Clarifier
•
Primary Sludge + 50% TFC Sludge
mgIL ppd
Flow 0.074
BOD 30,246 18,711
TSS 40,000 24,745
NH3-N 32 20
Del Monte Influent
mgIL ppd
Flow
BOD
TSS
NH3-N
0.33
4218 11,610
461 1,269
4 10
Total PC Effluent
mg/L
ppd
I I dims
Flow
16.30
0.36 mgd
18858 ppd
BOD
330
44,873
2752
TSS
184
25,043
1536
NH3-N
31
4,224
259
89 ppolkcf
By -Pass
mg/L ppd
Flow 4.50
BOD 330
TSS 184
12,394
6,917
NH3-N 31 1,167
Aeration
Basin
1
Trickling Filter Influent
mg!L ppd
Flow
BOD
TSS
11.80
330 32,479
184 18,126
NH3-N 31 3,057
Aeration Basin Influent
mg!L ppd
Flow 16.30
BOD 177 24,087
TSS 108 14,687
NH3-N 17 2,348
Waste Activated Sludge
mglL ppd
Flow (mgd; 0.31
%conc 0.5
TSS 5000 13,030
5 Basins
Trickling
Filter
156
108
21
Trickling Filter Clar Eff
mglL ppd
Flow
BOD
TSS
NH3-N
11.80
119 11,693
79 7,770
12 1,181
CMAS
21164
14,687
2923
Ma
Trickling Filter Clar Sludge
m�/L ppd
50% TF Sludge
To DAF
Flow (mgd; 0.09
BOD 10032 7,795
TSS 15000 11,655
NH3-N 12 9
%conc 1.5
0.045 mgd
3898 ppd
5828 ppd
4.5 ppd
0.36 mgd
18858 ppd
Total Sludge = 43,602 ppd
BLACK & VEATCH ACTIVATED SLUDGE MODEL
ADG
GVD
OWNER Yakima
PLANT WWTP
PROJ NO.
WORK
MM 2024 Del Monte
5 basins in service
COMPUTED BY
DATE 9/14/2004
B&V FILE NO.
CHECKED BY
DATE 9/14/2004
INPUT TO CMAS MODEL
Tot Vol, cu ft
702,000 alpha
0.65 Elevation, ft
1065
Anoxic Vol,(%)
beta
0.95 Station Pres,psi
14.15
Tot det Tim, hr
Min DO @Pk, mg/I
1 SW depth,ft
26
Anox Det Tim,hr
Min DO @Ave,mg/I
2 Diffus depth, ft
25
Inf BOD, mg/I
156 Std Cs20, mg/I
11.10
Inf TSS, mg/I
108 Amb Cs, mg/I
10.45 FINAL CLARIFIERS
Eff TSS, mg/1
15 SRT, days
8 No. of Clarifiers
2
NonBVSS
0.30 RAS TSS, mg/I
7,500 Clarifier SWD, ft
15
VSS/TSS
0.82 MLSS, mg/I
Dia. of Clarifier, ft
140
lnf Ma, mg/I
21 Inf TKN, mg/I
20 Design SOR, gpd/sf
Flow, mgd
16.3 NO3-N, mg/I
Floc Well HRT, min
MLSS Rec Q, mgd
Min Eff Alk, mg/I
100 Floc Well SWD, ft
Carb Peak Factor
1.3 Inf alk, mg/I
270 No. of Floc Turbines
Nitr Peak Factor
1.3 Temp, C
20.78 Max G, 1/sec
Diffuser type (Gen. Fine =1, Coarse = 3, Stat. Tube = 4)
1
STEADY STATE OPERATING CHARACTERISTICS
FINAL CLARIFIERS
Tot Det time, hr
7.73 Tot Vol, cf
702000
ClarifierTot. Area, sf
30787
Oxic Det time,hr
7.73 Oxic Vol, cf
702000
SOR, gpd/sf
529
Anox Det Time,hr
0.00 Anoxi Vol, cf
0
Dia. of Clarifier, ft
140
CALC. SRT
8.89
SLR(100%RAS),ppd/sf
24
SRT, days
8.00 BOD Load, ppd/kcf
30
Clarifier HRT, hrs
5.1
Req SRT, days
5.69
Floc Well Diam., ft #DIV/01
Min SRT, days
3.00
Turbine Power,bhp/unit #DIV/0!
CARBONACEOUS
NITROGENOUS
COMBINED
Unmet Frac, mg/I
1.26
Eff SNH, mg/I
0.02
Unmet Frac, mg/I
1.26
Act Mass, mg/I
747
Act Mass,mg/I
63
Act Mass, mg/I
810
End Mass, mg/l
606
End Mass, mg/I
51
End Mass, mg/I
657
MLVSS, mg/l
2012
MLVSS, mg/I
114
MLVSS, mg/I
2126
MLSS, mg/I
2630
MLSS, mg/1
125
MLSS, mg/I
2755
F/Mv Ratio
0.24
F/Mv Ratio
0.23
Eff BOD, mg/I
4.7
Eff BOD, mg/I
4.8
WAS, ppd
12360
WAS, ppd
685
WAS, ppd
13045
WVS, ppd
9456
WVS, ppd
609
WVS, ppd
10065
WMa, ppd
3510
WMa, ppd
324
WMa, ppd
3833
AvgdO/dt, mg/I/h
28.8
AvgdO/dt, mg/I/h
9.3
AvgdO/dt, mg/I/h
38.2
Pk dO/dt, mg/l/h
32.3
Pk dO/dt, mg/l/h
12.0
Pk dO/dt, mg/l/h
44.3
DENITRIFICATION
Pk Kla 20, I/h
7.5
Ave ANXdO/dt,mg/l/h
0.0
Ave KLa 20,I/h
7.3
Ave Den AOS, pph
0
Alk Req, mg/I
0
Ave TAOR, pph
1673
Ave Anox AOR, pph
0
Eff NO3, mg/I
14.7
Ave SOTR, pph
3562
Eff Alk, mg/I
165
Pk TAOR,pph
1938
Pk ANOdO/dt,mg/l/h
0.0
Eff TKN, mg/I
0.9
Pk SOTR, pph
3664
Pk Den AOS, pph
0
N in WAS, mg/I
4.36
RAS Flow, mgd
9.1
Pk Anox AOR, pph
0
Min N Req, mg/I
5.29
WAS Flow, gpd
208549
BLACK & VEATCH ACTIVATED SLUDGE MODEL
OWNER Yakima COMPUTED BY
PLANT WWTP DATE
PROJ NO. B&V FILE NO.
WORK CHECKED BY
MM 2024 Del Monte DATE
5 basins in service
ADG
9/14/2004
GVD
9/14/2004
AERATION EQUIPMENT DESIGN
INPUT TO AERATION MODEL
DIFFUSER SYSTEM
Design SOTR, pph
3664
Lateral Spacing, ft
3
Diffuser Area, sf
0.410
Airflow per diffuser, scfm/diff
1.5
Min Air for Mixing, scfm/kcf (Fine = 15, Coarse = 20)
15
Number of Diffuser
9500
BLOWER SYSTEM
Peak Ambient Temp, F
110
Average Ambient Temp, F
65
Blower Efficiency,%
55
Headloss thru Diffuser (Fine = 1, Coarse = 0.5)
1
MECHANICAL AERATION
Design SOTR, pph
0
Transfer Efficiency, lbs 02/hr/bhp
(Low Speed: 3.2 for <75 HP; 3.0 for 75<HP<100; 2.8 for HP>100);(High Speed = 2.0)
Aerator Size, nhp/unit
Minimum mixing power, bhp/kcf
0.75
Motor Service Factor, bhp/nhp
0.87
OUTPUT FROM AERATION MODEL
DIFFUSER SYSTEM
Process Airflow,scfm
7184
Minimum Air for Mixing, scfm
10530
Design Airflow (without 10% safety factor), scfm
10530
Oxygen Transfer Efficiency (OTE), % (OTE = 0 for Mixing limited Cond.)
0.0
Number of Diffusers
9500
Airflow per diffuser, scfm/diff
1.1
Tank Area/Diffuser Area (At/Ad)
6.9
Diffuser Density, sq ft/diff
2.8
BLOWER SYSTEM
Blower HP at Peak Temperature, whp
871
Blower HP at Ave. Temperature, whp
803
Blower HP for Mixing at Ave. Temperature, whp
803
MECHANICAL AERATION
Total Aerator Process Power, bhp
0
Total Aerator Mixing Power, bhp
0
Design Aerator Power, bhp
0
Number of Aerators
0
Table 5-9
Current DAFT Loading and Theoretical Capacity
Combined WAS and
Trickling Filter Solids
(pp (1)
SLR'
(lb/hr/s#)
Current Operation
Annual Average
7,7003
8,9003
0.4
0.5
Maximum Month
2024 Operation with TF solids2
Annual Average
17,000
0.9
Annual Average (24 hour)
17,000
0.4
Maximum Month
25,000
1.34
Maximum Month (24 hour)
25,000
0.7
Theoretical DAFT Capacity
Without polymer addition
8,000
0,4
Without polymer addition (24 hour)
16,000
0.4
With polymer addition
19,000
1.0
With polymer addition (24 hour)
38,000
1.0
'SLR based on 12 hr/day, 7 day/week operating schedule, unless otherwise noted.
2Assumes 100 percent of trickling filter solids are thickened through DAFT.
3Current quantities do not always include trickling filter solids.
4Exceeds recommended SLR,
Table 5-11
Existing Digester Tankage Capacity
2004
2024
Average
Annual
Maximum
Month
Average
Annual
Maximum
Month
WAS, ppd
5,500
7,400
7,500
13,000
Primary solids, ppd
9,100
12,500
13,000
19,000
Trickling Filter solids, ppd
6,300
11,200
9,500
12,000
Total Solids, ppd
20,900
31,100
30,000
44,000
Combined Solids, %'
4.1
4.1
4.1
4.1
Total Solids, gpd
61,100
91,000
88,000
129,000
Primary HRT, days
27
18
19
132
Secondary HRT, days
11
7
7
5
'Solids concentration based on treating 50 percent of the trickling filter solids through the DAFT
and 50 percent through the primary clarifier.
2Primary digester capacity does not provide 15 day detention to meet 40 CFR Part 503
requirements for Class B solids.
STATE OF WASHINGTON
DEPARTMENT OF ECOLOGY
1.5 West Yakima Avenue, Suite 200 • Yakima, Washington 98902-3452 • (509) 575-2490
September 2, 2004
Max Linden
City of Yakima
Wastewater Division
2220 E. Viola
Yakima, WA 98901
RE: Draft 2004 Wastewater Facility Plan - Permit Condition S11.A
Tracking Number 0403-1
Dear Mr. Linden:
Your address
is in the
'..owes•
watershed
Ecology has reviewed the City's Draft Facility Plan. The Facility Plan proposes and provides
justification for an estimated $30 million worth of capital improvements over the next six years.
The Department has several comments regarding the facility plan. The Final Facility Plan must
address these comments. Due to the large number of concerns raised with the plan, the
Department would like to suggest a meeting be held between Department representatives and
City technical personnel.
1. Page 2-21 states that DOE is considering ground water protection regulations. WAC
173-200 - Water Quality standards for Ground Waters of the State of Washington was
promulgated in 1990.
2. Page 10-15 indicates the I/I is excessive, as does the City's 2003 I/I report to the
department. In the past, the city has discussed a plan for evaluating and ranking I/I
removal projects in the collection system. What is the status of this report? Prior to
considering any upgrades that are hydraulic bottlenecks (i.e. additional clarifiers), the
cost effectiveness versus I/I reduction must be considered.
3. Page 2-19 states that the city's treatment plant is designated Reliability Class II. The
Department concurs with this designation. At several later points in the report,
processes are evaluated against the more stringent Class I criteria, where Class II criteria
should apply.
4. The draft plan does not establish the design capacity for the existing plant. Without this
analysis the Department cannot finalize the permitted load to the treatment plant.
5. In several places the report simply asserts capacity values for process components.
Calculations are not typically provided. The mass balance was not provided for the
overall process. Provide the calculations or describe the basis for process evaluations or
treatment unit capacities. ;;y,,,,e 7.7 tplIN ruPCN
1promait;mmi
L
.ti`•: 'S.�a: i' sT'��?'�1�3.'tx:1':Lsa.i� ii�1Lw's..u. .:: A: r4.'aai :.,t.i;ibs..e7; C..... vi.::;,tit'i-' 4N :�rL- .�..�=... _..±i_:.c4:•u 1.iti,ds]r\�_u��.=Y4: �s. :'.•� .: �.: .�_.. .rsi �`.�i. ststK ::h:,v'i'-1:atF.'�i. -
Max Linden
City of Yakima — Wastewater Division
September 2, 2004
Page 2
6. The department has several questions regarding the process model referenced on page
5-14. Provide the process mass balance for review.
7. The report typically describes the capacity of the trickling filter and aeration basin
systems in terms of flow (MGD). This is misleading because the waste strength affects
the "flow" capacity. To be consistent, describe the capacity of the system to oxidize
BOD in lbs/day.
8. Modify the Metals Study Scope of Work (Appendix E) to include an evaluation of
hardness adjustment for the City's source water. Metal toxicity is highly dependant on
water hardness. In fact, the city's influent metals concentrations are not significantly
higher than other cities; the City's extraordinarily low water hardness was the primary
cause for metals limits.
9. Appendix F - Mixing zone study. This was previously reviewed in Aug '03. Based on
the Departments review, it appears reasonable to increase the 7Q10 used for permitting
to 834 cfs from 632 cfs.
10. The final report must describe compliance with SEPA and NEPA if applicable.
Projected Waste Loads (Chapter 4)
1. Table 4-3 uses ammonia data, and appears to underestimate the nitrogen loadings to the
plant by approximately 20%. TKN data available from June 2003 to June 2004 indicate
an average annual loading of 2,330 ppd. These low estimates will impact the design of
the activated sludge and aeration systems. The BOD/TKN ratio appears to be slightly
greater than 10:1, indicating the highly industrial nature of the waste stream.
2. What is the basis for the assumption that flows will decrease drastically in the next 20
years (Section 4.3.2)? This plan does not propose the type of aggressive I/I removal
program that would justify this assumption.
3. The plan assumes that Del Monte will not expand operations or need additional capacity
at the WWTP over the next 20 years (page 4-10 and Table 4-7). What is the basis for this
assumption? Was Del Monte contacted regarding any plans for expansion?
Headworks
1. The Bar Screen and the Grit system do not appear to meet redundancy requirements. If
one unit is out of service peak flows will exceed the capacity of the remaining unit.
Discuss the resulting impact to the process (sewage overflow, poor screenings removal,
equipment damage). Evaluate the need for additional redundancy.
2. It is not clear from the text or figures that both flumes can operate in parallel and record
the totalized flow. Is this mode of operation possible?
Primary Clarification
1. Page 5-14 indicates the primary clarifiers remove 36% of the BOD and 51% of the TSS.
Do these estimates consider the impact of thickening trickling filter solids in the primary
clarifiers?
Max Linden
City of Yakima — Wastewater Division
September 2, 2004
Page 3
2. I cannot duplicate the calculations that lead to the surface overflow rates shown on page
5-21.
3. Page 5-22 mentions grease and plugging problems in the primary clarifiers. While the
plan proposes no specific solution preventing grease discharges through education and
the pre-treatment program should be considered.
4. It is unclear how replacing the sluice gates will solve the flow splitting problem into the
primary clarifiers. Consider an energy dissipating weir or other hydraulic mechanism.
Trickling Filters
1. Page 5-14 assumes that the trickling filter can accept a surface load of 90 lb/kcf/day.
Metcalf & Eddy indicate that 60 lb/kcf/day is a more appropriate maximum for rock
filters. It seems likely that trickling filter performance would degrade if loaded at 90
lb/kcf/day. Figure 5-6 seems to support this.
2. Figure 5-6 shows approximately 30% BOD removal through the trickling filter process.
Page 5-14 states the assumption that the htickling filters remove 40% of the BOD and
60% of the TSS. Do both of these estimates make the same assumptions? Do they
include the trickling filter clarifier or just the trickling filters themselves?
3. Figure 5-6 shows three different sets of data. What does each represent? They are not
labeled in the figure.
4. Was any analysis performed to support the assumption that plastic media in the
trickling filters would not increase their performance? It seems reasonable that plastic
media could double the available surface area for biological growth.
5. What is the assumed recirculation rate for the trickling filters?
6. How does plant staff currently thicken trickling filter solids? What thickening options
does the existing plant allow? Page 5-41 indicates that the process model was based on a
50:50 flow split between DAF and primary clarifiers, but Page 9-3 indicates that trickling
filter solids cannot be sent to both the DAF and headworks at the same time.
Aeration Basins
1. The report cites three numbers as the "capacity" or the aeration basins, 53,400
lbs-BOD/day, 3,000 mg/L MLSS, and 14,400 scfm. Provide justification for these
capacities. Include a process evaluation that includes the trickling filters, the aeration
basins and aeration system. Include the mass balance with the analysis. Describe the
reactor kinetics. Calculate oxygen requirements.
2. The plant will likely face discharge limitations for orthophosphate within 10 to 15 years.
Investigate how phosphate treatment will be accomplished. Consider the need to
modify the plant to remove phosphate in each alternative considered.
3. The alternatives considered in Chapter 6 cannot be objectively compared. Use consistent
assumptions for time frame and treatment requirements when comparing alternatives.
+.F.anw�,o-:cew- Y.•.ei: a:aweaua:" •�.tS7s..:..w �.: s. eT-+:.� ;s�i._L-i.v �..•..moi`- ri tb•.>.ISLi.ri-.:.�: k.' .-�i:_ .-1 ��•.�"�: e,: 5-74.
. ._. _ \:�.... _ _�.. t+:�E�3tii.5C'nim'•2e�t5'w�si.Y.�:.S:.b4�i'e. r,r
Max Linden
City of Yakima - Wastewater Division
September 2, 2004
Page 4
4. All the alternatives presented appear to undersize the anoxic zone, which is typically
30%-40% of the aeration volume. No calculations are provided for denitrification
kinetics. Based on the numbers available, I calculate a nitrate removal rate of 500 ppd, a
fraction of the total nitrogen loading. The anoxic zone is also too large to function
effectively as a selector; the F/M gradient is too small. I calculate an F/M of 1.4 across
the zone. Perhaps with internal compartments an adequate gradient could be
maintained.
5. Evaluate an alternative that provides complete denitrification, which would then allow
the basin to operate at a MLSS greater than 3,000 mg/L. Also hull consider that
denitrification will reduce the aeration requirements for the system. Compare the total
life cycle costs of the alternatives.
6. Page 6-15 recommends downsizing the capacity of the aeration blowers. No justification
is provided for this recommendation. Provide calculations for the system aeration
requirements. The final recommendation for the air system should address the reported
blower cycling. Evaluate an automatic feedback control loop to control the DO in the
basins.
Secondary Clarification
1. Calculations are generally not included for capacities presented in the report. I can't
duplicate the calculation on page 5-32 or peak hour overflow rate of 1030 gpd/sf for the
Secondary Clarifiers. I can't duplicate the calculations on page 5-33 that lead to 15.98
and 16.3 as the flow capacities based on solids loading considerations. Also the numbers
in table 5-8 don't match the MLSS concentration assumptions made earlier in the
chapter.
2. The report recommends building a third secondary clarifier ($3,370,000) based on
meeting class I reliability; however only class II reliability is required. Page 5-34 further
indicates that the new secondary clarifier is required to protect against the event that
both the trickling filter clarifier and one of the secondary clarifiers are off line at the
same time. No mass balance or process calculations are provided to justify this
contention.
3. What assumptions went into the estimated WAS pumping rates? I can't duplicate the
flow rates presented on page 5-36.
4. Chapter 5 concluded that the odor control system was functioning adequately and
effectively. Why are upgrades to the system ($1,112,000) proposed in chapter 6?
Disinfection
1. The UV systems evaluated do not appear to be capable of disinfecting peak flows. In
addition to average annual flow, disinfection systems need to disinfect peak flows.
2. The draft plan does not make a recommendation regarding disinfection. The final report
must contain a concrete proposal.
Max Linden
City of Yakima - Wastewater Division
September 2, 2004
Page 5
Solids handling
1. The report proposes a second DAF unit ($2,000,000) to provide redundancy. In general
Ecology only requires redundant equipment for the main wastewater treatment system,
not solids thickening or treatment. Evaluate the plants ability to continue to provide
adequate solids treatment if the DAF is offline for routine maintenance. Consider the
ability of the digesters to thicken through decanting.
2. The report proposes a new primary digester ($5,384,000) to provide redundancy. In
general Ecology only requires redundant equipment for the main wastewater treatment
system, not solids thickening or treatment. Evaluate the plants ability to comply with
the 503 regulations while one digester cell is offline for routine maintenance. Evaluate
the relative costs of constructing a new primary digester cell to another method. At a
minimum consider: 1) Meeting 503 requirements by testing, 2) meeting the requirements
by lime application, 3) hauling sludge to NSF composting facility for further
stabilization.
3. Tables 5-9 and 5-11 appear inconsistent. Provide the solid treatment system mass
balance.
4. The report proposes a new centrifuge and polymer unit ($3,103,000) to provide
redundancy. In general Ecology only requires redundant equipment for the main
wastewater treatment system, not solids thickening or treatment. Evaluate the plants
ability to store solids while the centrifuge is offline for routine maintenance. Evaluate
the cost of hauling liquid sludge to Natural Selection Farms during this time period.
5. Page 9-10 discusses the centrate equalization facility. Evaluate the process impact of
returning the centrate to headworks, the trickling filter pump station, or directly to the
aeration basin.
If you have any questions please don't hesitate to contact me at 509-454-7846.
Water Quality Program
DCD:tiw
cc: Douglas Kobrick, P.E. - Black & Veatch
•
July 6, 2004
CITY OF YAKIMA
WASTEWATER DIVISION
2220 East Viola
Yakima, Washington 98901
Phone: 575-6077 • Fax (509) 575-6116
David Dunn
Dept. Of Ecology
15 West Yakima Ave. Suite 200
Yakima, WA 98902
Re: City of Yakima 2004 Wastewater Facility Plan/Wastewater Connection Charge Study
1 recently sent you a letter notifying you about a public hearing to receive comments on the 2004 Wastewater
Facility Plan along with the proposed revisions to the Wastewater Connection Charge Study and subsequent
revisions to wastewater rates and charges.
This hearing was scheduled for July 19, 2004 but has now been postponed to a later date. You will be notified when
the hearing is rescheduled and if you have any questions 1 can be contacted at (509) 249-6814.
Sincerely,
Max • en
Utili , gineer
Wast ater Division
June 29, 2004
CITY OF YAKIMA
WASTEWATER DIVISION
2220 East Viola
Yakima, Washington 98901
Phone: 575-6077 • Fax (509) 575-6116
David Dunn
Department of Ecology
15 West Yakima Ave, Suite 200
Yakima, WA 98902
Re: City of Yakima 2004 Wastewater Facility Plan
Of EGOj-CL
Received
All 2 9 20i'
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4
RF(;40�
On March 24, 2004 an initial letter was sent to you for comment regarding the development of the City of Yakima's
Draft 2004 Wastewater Facility Plan. We have received comments from several organizations and will respond to
those comments in the near future. If you have not commented, and plan to, we would appreciate responses back no
later than July 15, 2004.
The Yakima City Council will conduct a public hearing to receive comments on the 2004 Wastewater Facility Plan
along with the proposed revisions to the Wastewater Connection Charge Study and subsequent revisions to
wastewater rates and charges.
The Facility Plan describes the planning, findings, and recommendations for the Yakima Regional Wastewater
Treatment Plant and the City of Yakima Collection System that are necessary to maintain system reliability; to
comply with regulatory laws, rules, regulations, and requirements by federal and state agencies; and to provide
adequate capacity to meet the needs of the service area over the next 20 years.
The proposed revisions in the Wastewater Connection Charge Study recommend an adjustment to the connection
charge for all new accounts to include historical cost and future cost components for the treatment facility,
trunks/interceptors, and collection piping.
Written comments can be submitted to the Council in two ways:
1) Send a letter via regular mail to "Yakima City Council, 129 N. 2"d Street, Yakima, WA 98901; or,
2) E-mail your comments to ccouncil@ci.Yakima.wa.us. Include in the e-mail subject line, "Wastewater
Public Hearing," Please also include your name and mailing address.
Comments may be provided to Council at the meeting, or sent to them in their meeting packet if provided to the City
Clerk prior to noon on Thursday, July 15, 2004.
The public hearing will be held on July 19, 2004 at 7:00 p.m. in the Council Chambers At Yakima City Hall, 129
North 2"d Street, Yakima, WA. I can be contacted at (509) 249-6814 if you have any questions about these two
issues.
Sincerely,
Max riden
Utili ngineer
Wastewater Division
I'I,1
CITY OF YAKIMA
IVASTEIVATER DIVISION
2220 East Viola
Yakima, Washington 98901
Phone: 575-6077 • Fax (509) 575-6116
June 11, 2004
David Dunn
Department of Ecology
Central Regional Office
15 West Yakima Avenue
Suite 200
Yakima, WA 98902-3401
Re: 2004 Wastewater Facility Plan
Dear Mr. Dunn:
We have made some minor changes to the Abbreviations Table and Sections 1 and 12 of
our 2004 Wastewater Facility Plan and have enclosed the corrected versions for you to
include in your copies of the plan. One change that you will note in Section 12 is that
UV disinfection has been moved into the 0-6 year Priority Improvements schedule.
If you have any questions regarding this document please contact me at (509) 249-6814.
Very truly yours,
Max L nr-n
Utility gineer
City of akima
Encl: 2 copies each of the 6/7/04 revisions to the Abbreviations table and Sections 1 and
12 of the City of Yakima's 2004 Wastewater Facility Plan
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BLACK & VEATCH
Black & Veatch Corporation
Seottle. Washington
CITY OF YAKIMA
YAKIMA REGIONAL WASTEWATER TREATMENT PLANT
EXISTING SITE PLAN
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CITY OF YAKIMA
WASTEWATER DIVISION
2220 East Viola
Yakima, Washington 98901 1
6
Phone: 575-6077 • Fax (509) 575-6116 1
\t?
l.�
GQ� OF Ecozoo
C�' RRcmved
September 1, 2005
State of Washington
Department of Ecology
15 West Yakima Avenue, Suite 200
Yakima Washington 98902-3452
Dear: Mr. David Dunn
SEP 41 2005
ss
94, REGIONO��i`
RE: Finalization of State Environmental Review Process (SERP) and updates to the City of
Yakima's Draft 2004 Wastewater Facility Plan.
The Environmental Report (ER) and updates to the City of Yakima's Draft 2004 Wastewater
Facility Plan is enclosed for your review and final approval. This submittal completes the
Facility Plan as required by WAC 173-240-060.
Attached as exhibits to the ER are the Initial Letter, State Environmental Policy Act (SEPA)
checklist and DNS along with comments received and responses from the City of Yakima
Wastewater Division. Also included as exhibits are the notifications, study sessions, meetings,
public hearing, mailing lists, agendas, resolutions for adoption, and many other exhibits required
to complete the Environmental Report.
A description of the location of specific updates to the Facility plan are attached and described
by section for your convenience.
If you have further question or need additional information I can be contacted at 249-6814.
Very truly yours,
'411:44
Max ' en
Utilit 'ngineer
Wast ater Division
1�
YAKIMA REGIONAL WASTEWATER TREATMENT PLANT
2004 WASTEWATER FACILITY PLAN
DRAFT
FEBRUARY 2004
Prepared For
City of Yakima
Yakima, Washington
EXPIRES 10-17-05
Prepared By
BLACK & VEATCH
of Eco\
Recewi..dO�
'FEB 2 B 2004
4�9'Q{ REG10\A
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ACKNOWLEDGEMENTS
Black & Veatch would like to acknowledge the following for their contribution to the
City of Yakima 2004 Wastewater Treatment Plant Facility Plan,
City of Yakima Wastewater Division
Doug Mayo
Max Linden
Joe Schnebly
Scott Schafer
Steve Brown
Mike Price
Arnold Swain
Daryl Bullard
Tim Cooper
Marie Bossert
Associated Firms
Conley Engineering, Inc.
Cosmopolitan Engineering Group
Panhallegon Associates Consulting Engineers (PACE), Inc.
HDR Engineering, Inc. prepared the Draft 2000 Wastewater Facilities Plan from which
various sections have been duplicated or updated.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page ACK-1
TABLE OF CONTENTS
SECTION 1- EXECUTIVE SUMMARY
1.1 Background 1-1
1.2 Discharge and Treatment Requirements 1-2
1.3 Service Area Characteristics 1-8
1.4 Wastewater Flows and Loadings 1-9
1.5 Analysis of Existing Wastewater Treatment Plant 1-11
1.6 Identification of Selected Wastewater Treatment Strategies 1-16
1.7 SCADA and Electrical Power 1-19
1.7.1 Power Distribution System Assessment 1-19
1.7.2 EPA Class I & II Reliability and WDOE Requirements 1-19
1.8 Gas Utilization and Cogeneration 1-21
1.9 Biosolids Management 1-21
1.10 Identification of Selected Wastewater Collection Strategies 1-24
1.11 Existing System Deficiencies 1-24
1.12 Financial Planning/Implementation 1-25
1.12.1 Wastewater Treatment Plant Improvements 1-26
1.12.2 Projection of Facility Improvement Financing 1-29
1.12.3 Projected Budget and Recommendations 1-34
SECTION 2 — DISCHARGE AND TREATMENT REQUIREMENTS
2.1 Introduction 2-1
2.2 Surface Water Quality Standards 2-5
2.2.1 Revised Surface Water Quality Standards 2- 6
2.2.2 Antidegradation 2-7
2.2.3 Criteria 2-7
2.3 NPDES Permit 2-8
2,3.1 Development of Mixing Zone -Based NPDES Permit Limits 2-10
2.3.2 Development of Watershed -Based Effluent Limits 2-11
2.3.3 Water Quality Criteria for Conventional Parameters 2-11
2.3.4 Water Quality Criteria for Toxicants 2-12
2.3.5 Mixing Zone Regulations 2-12
2.3.6 Critical Effluent Flows 2-14
2.3.7 Recommended Water Quality -Based Effluent Limits for the Current NPDES
Permit 2-14
2.3.8 Projected Water Quality -Based Effluent Limitations at Buildout 2-15
2.4 Future Basin -Wide Water Quality Issues 2-16
2.4.1 Temperature 2-16
2.4.2 Biochemical Oxygen Demand 2-17
2.4.3 Phosphorus 2-18
2.5 Reliability Classification 2-19
2.6 Biomonitoring and Whole Effluent Toxicity Testing 2-19
2.7 Infiltration and Inflow Control 2-21
2.8 Groundwater Protection and Impacts on Unsewered Areas 2-21
2.8.1 General Groundwater Quality and Protection 2-21
2.8.2 Regulation of Septage Disposal 2-22
2.9 Biosolids Management 2-23
2.9.1 Federal Regulations 2- 24
2.9.2 Washington Regulatory Guidance 2-24
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page TOC -1
2.10 Land Application of Treated Wastewater 2-24
2.10.1 National Perspective 2-25
2.10.2 Washington Regulatory Review 2-25
2.10.3 Regional Water Reuse 2- 27
2.11 Wetlands for Wastewater Treatment 2-28
2.12 Land Application of Food Processing Waste 2-28
2.13 Endangered Species 2-29
2.14 Washington Salmon Recovery 2-33
2.15 Pretreatment 2-34
2.16 Air Pollution 2-37
2.16.1 The Clean Air Act and Rules for the Control of Air Pollution in Washington 2-37
2.16.2 Clean Air Act Risk Management Plans 2-38
2.16.3 Chorine -Specific Regulations 2-39
2.17 Virus Control 2-40
2.18 Noise 2-41
2.19 Stormwater 2-41
SECTION 3 - SERVICE AREA CHARACTERISTICS
3.3 Current and Projected Population 3-1
3.11 Current Land Use 3-4
3.13.2 Union Gap Urban Service Area 3-5
3.13.3 Terrace Heights Urban Service Area 3-6
3.14 Future Land Use 3-8
3.15.4 Union Gap Urban Service Area 3-8
3.15.5 Terrace Heights Urban Service Area 3-9
SECTION 4 — EXISTING AND PROJECTED WASTEWATER
CHARACTERISTICS
4.1 Introduction 4-1
4.2 Current Wastewater Characteristics 4-1
4.3 Historical Flows and Loadings 4-2
4.3.1 Wastewater Unit Flows and Loadings 4-8
4.3.2 Unit Flows Determination 4-8
4.3.3 Unit Wasteload Determination 4-9
4.4 Projected Flows and Loadings 4-10
SECTION 5 — ANALYSIS OF EXISTING WASTEWATER TREATMENT
PLANT
5.1 Introduction 5-1
5.2 Description of Existing Facilities 5-1
5.3 Process Analysis 5-14
5.3.1 Plant Capacity 5-16
5.4 Process Unit Capacity Evaluation 5-18
5.4.1 Preliminary Treatment 5-18
5.4,2 Primary Treatment 5-20
5.4.3 Secondary Treatment 5-23
5.4.4 Final Disinfection 5-36
5.4.3 Outfall and Outlet Box Facilities 5-37
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page TOC -2
5.4.4 Non -Potable Water System 5-38
5.4.5 Solids Thickening 5-38
5.4.6 Solids Digestion 5-40
5.4.7 Solids Dewatering 5-43
5.4.8 Miscellaneous Systems/Facilities 5-44
5.5 Summary 5-46
SECTION 6 - IDENTIFICATION OF SELECTED WASTEWATER
TREATMENT STRATEGIES
6.1 Introduction 6-1
6.2 Existing Facilities Needs and Improvements 6-1
6.2.1 Headworks/Preliminary Treatment 6-1
6.2.2 Primary Treatment 6-2
6.2.3 Trickling Filter System 6-3
6.2.4 Activated Sludge System 6-5
6.2.5 Secondary Clarifiers 6-10
6.2.6 RAS/WAS Pumping 6-13
6.2.7 Aeration Blowers 6-14
6.3 Disinfection Alternatives 6-23
6.3.1 Alternatives Considered 6-23
6.3.2 Alternatives Evaluation 6-28
6.3.3 Recommendations 6-31
6.4 Air Emission Treatment Technology Review 6-32
6.4.1 Atmospheric Dispersion 6-32
6.4.2 Air Emission Modification 6-32
6.4.3 Liquid Phase Treatment 6-33
6.4.4 Vapor -Phase Treatment 6-34
6.4.5 Unit Processes Which Have Potential Sources of Air Emissions 6-37
6.4.6 Review of System Strategies 6-39
6.4.7 Opinion of Probable Costs 6-41
6.4.8 Recommendations 6-41
6.5 Wastewater Treatment Plant Operations, Maintenance and Support Programs 6-42
6.5.1 Operations and Maintenance Staffing 6-42
6.5.2 Pretreatment Program 6-44
6.5.3 Strong Waste Program 6-46
6.5.4 Wastewater Laboratory Staffing and Operation 6-47
6.6 Maintenance Improvement Projects 6-49
SECTION 7 — ANALYSIS OF POWER DISTRIBUTION AND SCADA SYSTEMS
7.1 Introduction 7-1
7.2 Existing Power Distribution System 7-1
7.2.1 Utility Service 7-1
7.2.2 Normal Power 7-1
7.2.3 Standby Power 7-2
7.2.4 Existing Power Distribution System Assessment 7-2
7.3 Power Distribution Capacity and Required Modifications 7-3
7.3.1 Power Distribution System Capacity 7-3
7.3.2 EPA Class I & II Reliability and WDOE Requirements 7-4
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page TOC -3
7.4 SCADA Components 7-7
7.4.1 Electronic Controllers 7-7
7.4.2 Human Machine Interface Software 7-9
7.4.3 Computer Hardware & Software 7-9
7.4.4 Network Communications 7-9
7.5 SCADA Issues 7-10
7.5.1 Technical Support 7-10
7.5.2 System Reaction Time 7-10
7.5.3 Report Generation 7-11
7.6 SCADA Options and Projected Costs 7-11
7.6.1 Option 1 — Maintain and Expand Existing System 7-11
7.6.2 Option 2 — Major SCADA Component Replacement 7-11
7.6.3 Option 3a — Incremental Major SCADA Component Replacement 7-12
7.6.4 Option 3b — Incremental Major SCADA Component Replacement 7-13
7.7 SCADA Recommendations 7-14
SECTION 8 — GAS UTILIZATION AND COGENERATION
8.1 Introduction 8-1
8.2 Digester Gas Production 8-1
8.3 Digester and Building Heating Requirements 8-1
8.4 Digester Gas Utilization 8-3
8.4.1 Current Gas Utilization 8-3
8.4.2 Cogeneration 8-3
8.5 Digester Gas System Improvements 8-5
8.6 Boiler Improvements 8-6
8.6.1 Boilers 8-6
8.6.2 Boiler Backup Fuel 8-6
8.6.3 Automatic Fuel Switchover 8-7
8.7 Recommendations 8-7
SECTION 9 - BIOSOLIDS MANAGEMENT
9.1 Introduction 9-1
9.2 Federal and State Regulations 9-1
9.3 Biosolids Quantity and Quality 9-1
9.4 Biosolids Final Use 9-3
9.5 Biosolids Processing 9-3
9.6 Expansion and Upgrade Requirements 9-5
9.6.1 Dissolved Air Flotation Thickening 9-6
9.6.2 Anaerobic Digestion 9-6
9.6.3 Dewatered Cake Storage 9-8
9.6.4 Centrate Equalization or Treatment 9-9
9.6.5 Dewatering 9-11
9.7 Class A Treatment Alternatives 9-18
9.7.1 Composting 9-19
9.7.2 Advanced Digestion 9-20
9.7.3 Alkaline Stabilization 9-21
9.7.4 Heat Drying 9-21
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page TOC -4
9.8 Selected Class A Treatment Alternatives 9-22
9.8.1 Class A Alternative 1 — Advanced Digestion 9-22
9.8.2 Class A Alternative 2 — Heat Drying 9-26
9.8.3 Class A Alternative Recommendation 9-28
9.9 Regional Solids Management 9-29
SECTION 10 - ANALYSIS OF EXISTING WASTEWATER COLLECTION
FACILITIES
10.1 Summary 10-1
SECTION 11 - IDENTIFICATION OF SELECTED WASTEWATER
COLLECTION STRATEGIES
11.1 Summary 11-1
SECTION12 - FINANCIAL PLANNING/IMPLEMENTATION
12.1 Introduction 12-1
12.2 Financial Policies/Regulatory Requirements 12-1
12.3 Wastewater Utility Funds 12-3
12.4 Current Revenue Sources 12-3
12.4.1 Rates 12-3
12.4.2 Connection Charges 12-4
12.4.3 Pretreatment Fees and Charges 12-4
12.4.4 Strong Waste Fees and Charges 12-4
12.5 Components of Wastewater Service Rates 12-5
12.5.1 Wastewater Collection and Maintenance (Service Unit 211) 12-5
12.5.2 Surface Drainage Collection Operation and Maintenance (Service Unit 213) 12-5
12.5.3 Rudkin Road Pump Station Operation and Maintenance (Service Unit 215) 12-5
12.5.4 Wastewater Treatment Operation and Maintenance (Service Unit 232) 12-5
12.5.5 Tax Expense 12-5
12.5.6 Wastewater Treatment Plant Capital Costs 12-5
12.5.7 Wastewater Collection System Capital Costs 12-6
12.5.8 Debt Expense 12-6
12.6 Basis of Accounting in Utility Operations 12-7
12,7 Current Wastewater Utility Rates and Charges 12-8
12.8 Other Methods of Financing 12-10
12.8.1 Bond Financing 12-10
12.8.2 State and Federal Grants and Loans 12-11
12.8.3 Pay -As -You -Go and Capital Reserve Funds 12-12
12.8.4 Development Based Funding 12-13
12.9 Summary of Recommended Improvements 12-14
12.9.1 Wastewater Treatment Plant Improvements 12-14
12.9.2 Collection System Improvements 12-20
12.10 Projection of Facility Improvement Financing 12-21
12.11 Annual Operation and Maintenance 12-27
12.11.1 Wastewater Treatment Program 12-27
12.11.2 Pretreatment/Strong Waste Program 12-27
12.11.3 Collection System Program 12-28
12.12 Projected Budget and Recomtnendations 12-28
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page TOC -5
APPENDICES
A National Pollutant Discharge Elimination System Waste Discharge Permit
B Draft Combined Quality Assurance Project Plan/Sampling and Analysis Plan
C Facility Plan Submittal Date Extension Correspondence
D SEPA and SERP Documentation (to be inserted)
E Metals Study Scope of Work Report
F City of Yakima WWTP Mixing Zone Study
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page TOC -6
ABBREVIATIONS
The following abbreviations are utilized throughout the City of Yakima 2004 Wastewater
Facility Plan.
Abbreviations
Full Term
4PA
Four Party Agreement
AA
Annual Average
AA
Atomic Absorption
ACEC
Acute Critical Effluent Concentration
AKART
All Known Available And Reasonable Technology
BA
Biological Assessment
BOD
Biochemical Oxygen Demand
CCEC
Chronic Critical Effluent Concentration
CCWF
Centennial Clean Water Fund
CO
Carbon Monoxide
CWA
Federal Clean Water Act
CPVC
Chlorinated Polyvinyl Chloride
DAF
Dissolved Air Floatation
DAFT
Dissolved Air Floatation Thickener
EBU
Equivalent Billing Unit
EPA
Environmental Protection Agency
FOG
Fats, Oils and Grease
GC/MS
Gas Chromatograph/Mass Spectrometer
GO
General Obligation
H2S
Hydrogen Sulfide
HDPE High -Density Polyethylene
HLR Hydraulic Loading Rate
HMI Human Machine Interface
HRT Hydraulic Retention Time
ICP/OES Ion Coupled Plasma/Optical Emission Spectrophotometer
KMnO4 Potassium Permanganate
Ib/dt Pounds Per Dry Ton
LID Local Improvement Districts
MACT Maximum Available Control Technology
mBtuh Thousand British Thermal Units Per Hour
MCC Motor Control Center
mgd Million gallons per day
MIU Minor Industrial Users
MM Maximum Month
NH4 Ammonia
NOx Nitrous Oxides
NPDES National Pollutant Discharge Elimination System
NSFBUF Natural Selection Farms Beneficial Use Facility
03 Ozone
OFM Office of Financial Management
City of Yakima Wastewater Facility Plan - DRAFT 6/7/04
Page ABB -1
Abbreviations
Full Term
OFR
Overflow Rate
ORP
Oxidation Reduction Potential
OUR
Oxygen Uptake Rate
Pb
Lead
PFRP
Process to Further Reduce Pathogens
PH
Peak Hour
PM10
Particulate Matter of Diameter Less Than 10 Microns
POTW
Publicly Owned Treatment Works
PPB
Parts Per Billion
PPM
Parts Per Million
PSM
Process Safety Management Plan
PVC
Polyvinyl Chloride
PWTF
Public Works Trust Fund
RAS
Return Activated Sludge
RCW
Revised Code of Washington
RMP
Risk Management Plan .
SCADA
Supervisory Control and Data Acquisition
SIUs
Significant Industrial Users
SLR
Solids Loading Rate
SOx
Sulfur Oxides
SO2
Sulfur Dioxide
SOR
Surface Overflow Rate
SRF
State Revolving Fund
State
State of Washington
SWD
State Waste Discharge
Ti/Re
Toxicity Reduction Evaluation
TF
Trickling Filter
TMDL
Total Maximum Daily Load
TPAD
Temperature Phased Anaerobic Digestion
TRC
Total Residual Chlorine
TSP
Total Suspended Particulate
TSS
Total Suspended Solids
UFC
Uniform Fire Code
UGA
Urban Growth Area
ULID
Utility Local Improvement Districts
USEPA
United States Environmental Protection Agency
Variable Frequency Drives
VFD
VOCs
Volatile Organic Compounds
WAC
Washington Administrative Code
WAS
Waste Activated Sludge
WDOE
Washington Department of Ecology
WDOH
Washington Department Of Health
WET
Whole Effluent Toxicity
City of Yakima Wastewater Facility Plan - DRAFT 6/7/04
Page ABB -2
Abbreviations
Full Term
WWTP
Wastewater Treatment Plant
City of Yakima Wastewater Facility Plan - DRAFT 6/7/04
Page ABB -3
SECTION 'i
EXECUTIVE SUMMARY
1.1 Background
The City of Yakima has operated a progressive sewer utility serving the needs of the
community since 1936 when a primary treatment plant was constructed to treat
wastewater prior to discharge to the Yakima River. Improved control of water pollution
was accomplished in 1955 by separation of food processing wastewater and domestic
sewage. In 1965, the City of Yakima added trickling filter biological treatment to the
sewage treatment process. Between 1974 and 1982, the City of Yakima accepted the
regional responsibility for treatment of wastewater and initiated a program that collects
and treats wastewater from the City of Union Gap, the Terrace Heights Sewer District,
and from other unincorporated developing areas within Yakima County lying within the
City's Urban Growth Boundary.
In 1988, the City of Yakima prepared a long term wastewater plan, as mandated by the
Washington Department of Ecology (WDOE), for the Yakima sewage collection system
and the Yakima Regional Wastewater Treatment Plant (WWTP) that identified
wastewater facility improvements needed to support the Metropolitan Area's economic
development goals; comply with federal/state laws, rules, and regulation; and to maintain
economical and reliable wastewater service.
Improvements at the Yakima Regional WWTP since 1988 include:
• Upgrading the aeration system for the activated sludge process with new blowers
and fine -air diffusers (1988).
• Modifications to the trickling filter pumping station, collection of air emissions
from the influent building, headworks building, trickling filter pumping station
and solids handling building with discharge to the trickling filters, covering of
trickling filters for control of air emissions, installation of two wet -scrubbers for
off gas treatment of circulated air from the trickling filters, improvements to
screening facilities, addition of a high solids centrifuge for biosolids dewatering,
addition of a dechlorination system, outfall diffuser, and expansion and
modifications to the laboratory (1992).
• Upgraded the facility nonpotable water system, rehabilitated the screening and
degritting area, enclosed the screening and degritting area for control of air
emissions with discharge of captured air to the trickling filters and wet -scrubbers,
installation of flexible domes over secondary digesters for methane gas
containment, and rehabilitation of primary digesters with fixed covers and
mechanical mixing (1998).
• Improvements to the Trickling Filter system which allowed for control of the
distributor arm speeds and better trickling filter clarifier operation (2002).
• Installation of trickling filter clarifier sludge line to the DAFT, and addition of a
trickling filter sludge pump enclosure, with new pump to discharge trickling
clarifier solids to the DAFT and to the Headworks facility (2002).
City of Yakima Wastewater Facility Plan - DRAFT 6/7/04 Page 1-1
In addition to these major improvements at the Yakima Regional WWTP, Yakima has
extended interceptors, trunk sewers, and local collection systems into previously
unsewered areas; has initiated sewer pipeline replacement projects for increased capacity
and rehabilitation of deteriorated pipelines; has implemented a chemical grouting
program within the collection system to reduce infiltration into the pipelines; began a
program of manhole repairs for rehabilitation and reduction of inflow and infiltration; and
implemented a root control program.
This 2004 Wastewater Facility Plan is intended to update and supplement the Draft 2000
Wastewater Facilities Plan as was reuir y the WDOE. This plan describes the
planning, findings, and recommendations for the Yakima Regional WWTP and the City
of Yakima collection system that are necessary to maintain system reliability; provide
adequate capacity to meet the needs of the Service Area; and to comply with regulatory
laws, rules, regulations, and requirements by federal and state government and agencies.
1.2 Discharge and Treatment Requirements
Regulatory and permitting issues that influence wastewater facility planning were
assessed in Section 2 of this report. Table 1-1 presents a summary of the regulatory and
permitting issues presented in this Section, with the status of each issue as it applies to the
Yakima Regional WWTP, and the level of concern regarding the issue. Treatment plant
NPDES discharge permit issues are included, as are related regulatory issues, which may
influence planning. Issues with a high level of concern are likely to require action in the
near future (within 10 years); a moderate level of concern indicates that regulations may
affect the operation of the treatment facility, but action is not likely to be required in the
near future (beyond 10 years) or will have a moderate impact on facilities; and a low level
of concern indicates that the issue has little effect on the operation of the wastewater
treatment facilities (beyond 20 -years).
Table 1-1
Summary of Regulatory and Permitting Issues
Regulatory
Issue/Parameter
Issues and Current Status
NPDES
Permit
Limits1
Importance
to Planning
Effluent Discharge
Wastewater Treatment Facility permitted flow to be
determined and will be established when the Final
Facility Plan is approved by DOE.
30 mg1L average monthly, 45 mg/L average weekly;
average monthly value may not exceed 15% of the
average influent concentration or 30 mg/L, whichever
is more stringent.
No current limitations. Concentration and load limits
are anticipated in 10 to 15 years. Phosphorus is likely
to be regulated
Y
C
N
High
Moderate
Moderate
WWTP Flow
BOD and TSS
Phosphonis
City of Yakima Wastewater Facility Pian - DRAFT 6/7/04
Page 1-2
Table 1-1
Summary of Regulatory and Permitting Issues
Regulatory
Issue/Parameter
Issues and Current Status
NPDES
Permit
Limits'
Importance
to Planning
Total Nitrogen
Anunonia Nitrogen
Chlorine Residual
pH
Bacteria
No current limitations. Concentration and load limits
are possible in 10 to 15 years.
No load limit. Concentration limit (4.16 mg/1
monthly ave., 12.3 mg/1 daily max).
Residual limit (0.012 mg/I monthly ave., 0.029 mg/1
daily max).
6.0 to 9.0
Fecal colifonn limits (200 organisms/100 ml monthly
geometric mean, 400 organisms/100 ml weekly
geometric mean) May be modified to e -coli in future.
N
C
C
Y
C
Moderate
I ligh
High
High
High
Metals
Interim Limit: 9.84 ug/L (average monthly), 14.36
ug/L (max daily)
Final Limit: 6.71 ug/L (average monthly), 9.80 ug/L
(max daily)
3.96 ug/L (average monthly), 5.77 ug/L (max daily)
2.18 ug/L (average monthly), 3.17 ug/L (max daily)
Interim Limit: 70.35 ug/L (average monthly), 95.82
ug/L (max daily)
Final Limit: 45.70 ug/L (average monthly), 66.70
ug/L (max daily)
Y
Y
Y
Y
High
Moderate
Moderate
High
Total Copper
Total Lead
Total Silver
Total Zinc
Biomonitoring Whole effluent toxicity testing required for acute and
chronic toxicity.
Y
High
Infiltration/Inflow Collection system rehabilitation projects have reduced
I&I. Infiltration is related to seasonal use of irrigation
system in the community.
S
High
Biosolids Biosolids management must meet 1) RCW 90.48.080
& Water Quality Standards; 2) applicable sections of
40 CRF Part 503 & Chapters 173-308 WAC,
"Biosolids Management"; 3) applicable sections of
Chapter 173-304 WAC, "Minimum Functional
Standards for Solid Waste Handling."
S
High
Virus Control May have stricter requirements in the future as
analytical methods improve.
N
Moderate
City of Yakima Wastewater Facility Plan - DRAFT 6/7/04
Page 1-3
Table 1-1
Summary of Regulatory and Permitting Issues
Regulatory
Issue/Parameter
Issues and Current Status
NPDES
Permit
Limits1
Importance
to Planning
Effluent
TMDL and Watershed
Planning
Ch lorine Byproducts
Effluent Reclamation
and Reuse
Several segments of the Yakima River are listed on
the State 303(d) list for TMDL development for
temperature, pH, sediments, Fecal Coliform,
turbidity, flow, and a variety of pesticides.
EPA may enact rules impacting the use of chlorine as
a disinfectant within the next 10-15 years.
WDOE Land Application Guidelines apply to
reclamation and reuse. Eluent reuse may be a
management tool for load diversion from the Yakima
River.
N
N
N
Moderate
Moderate
Moderate
Treatment Plant
Regulations apply to VOCs, H2S, C12; but not likely
to be considered major source.
Clean Air Act Section 112r Risk Management Plan
(RMP) requirements have a resubmission deadline of
June 21, 2004..
Yakima County Clean Air Authority potential Title V
Permit. Modeling indicated 609 lbs. of pollutants
potentially discharged into the air. This is below the
permitting threshold of 25 tons/year of air
contaminants.
N
N
N
Low
Moderate
Low
Air Emissions
Air Toxics
Air Contaminants
Visual Appearance
Maintenance of good neighbor policy has high
priority. No specific regulatory requirements apply;
subject to local standards. Defacto neighborhood
standards may dictate acceptable architectural
appearance.
N
High
Maintenance of good neighbor policy has high
Noise Control priority. City of Yakima regulatory requirements
apply.
N
High
Endangered Species Act - Legislation
relating to salmon recovery in
Washington has the potential to significantly impact
discharges, water conservation, and
of instream flows.
N
Moderate
Salmon
wastewater
management
Endangered Species Act - Other
ESA listings in Yakima County are identified in
text.
N
Low
Other the
City of Yakima Wastewater Facility Plan - DRAFT 6/7/04
Page 1-4
Table 1-1
Summary of Regulatory and Permitting Issues
Regulatory
Issue/Parameter
Issues and Current Status
NPDES
Permit
Limits'
Importance
to Planning
Pretreatment
DOE has approved the City's application for full
pretreatment authority and the permit formally
authorizes the City to implement its local pretreatment
program.
Y
High
Septage Acceptance
Landfill facility compliance issues with 503 and 308
regulations prohibiting acceptance of industrial
septage. WWTP looked to as possible disposal
option.
N
Moderate
Groundwater Protection
Continue to extend sewer service and limit
construction of new septic systems. Development
pressure driving use of on-site systems within the
Urban Growth Area.
N
High
Stormwater
EPA Phase 11 Stormwater Permitting regulation
became final on November 1, 1999. The City of
Yakima is in the process of implementing a regional
stormwater program. Coordination is ongoing.
N
Moderate
' Content of renewed NPDES discharge permit, coded as follows:
Y, Yes included
N, No, not included
C, Concentration Limit
S, Supplementary Condition
The City of Yakima Regional WWTP currently operates under National Pollution
Discharge Elimination System (NPDES) Permit No. WA -002402-3 issued by the State of
Washington Department of Ecology (WDOE). The permit was issued April 30, 2003,
and is effective June 1, 2003 through May 31, 2008, designating the WWTP as a Class 11
facility with respect to reliability criteria. The permit includes Special Conditions and
General Conditions. Special Condition sections are as follows:
S1 — Discharge Limitations
S2 — Monitoring Requirements
S3 — Reporting and Recordkeeping Requirements
S4 — Facility Loading
S5 — Operation and Maintenance
S6 — Pretreatment
S7 — Residual Solids
S8 — Acute Toxicity
S9 — Chronic Toxicity
S10 — Receiving Water and Effluent Study
Si l — Facility Plan
S12 — Outfall Evaluation
S13 — Schedule of Compliance
City of Yakima Wastewater Facility Plan - DRAFT 6/7/04 Page 1-5
In section Sl, the permit includes interim discharge limitations that are effective through
January 15, 2008, and final effluent limitations that are effective January 16, 2008
through May 31, 2008. The final effluent limitations reduce allowable maximum
monthly and daily concentrations of copper and zinc from the interim limits. All other
interim limits remain the same. Table 1-2 summarizes the current NPDES effluent
limitations.
Table 1-2
Current NPDES Effluent Limitations1
Parameter
Average Monthly2
Average Weekly
5 -day Biochemical Oxygen
Demand (BODS)
30 mg/L
85% Removal
45 mg/L
Total Suspended Solids (TSS)
30 mg/L
85% Removal
45 mg/L
Fecal Coliform Bacteria
200 colonies/100 mL
400 colonies/100 mL
pH3
Between 6.0 and 9.0 at all times
Parameter
Average Monthly
Maximum Daily4
Total Residual Chlorine (TRC)
0.012 mg/L
0.029 mg/L
Total Ammonia, as N
4.16 mg/L
12.3 mg/L
Total Coppers
9.84 (6.71) µg/L
14.36 (9.80) µg/L
Total Lead
3.96 µg/L
5.77 µg/L
Total Silver
2.18 µg/L
3.17 µg/L
Total Zinc5
70.35 (45.70) µg/L
95.82 (66.70) µg/L
Chronic WET Limit
No statistically significant difference in test organism
response between the chronic critical effluent
concentration (CCEC), 15.1% of the effluent, and the
control.
1 Average monthly and weekly effluent
except for fecal coliform, which is based
2 Average monthly effluent concentrations
average influent concentrations.
3 Indicates the range of permitted values.
4 Defined as highest allowable daily discharge,
calendar day.
5 Values in parentheses are final limitations
May 31, 2008. All other values are interim
limitations are based on the arithmetic mean of the samples taken
on the geometric mean.
shall not exceed 30 mg/L or 15% of the respective monthly
as the average measurement of the pollutant over the
effective January 16, 2008 through
and final limits.
Section S4 — Facility Loading requires facility loading design criteria to be determined
through development of an approved Facility Plan.
Section SID — Receiving Water and Effluent Study requires collection of receiving water
information necessary to determine if the effluent has a reasonable potential to cause a
violation of the water quality standards. If reasonable potential exists, WDOE will use
the information to calculate effluent limits. The effluent and receiving water must be
measured for hardness and ten metals.
City of Yakima Wastewater Facility Plan - DRAFT 6/7/04 Page 1-6
Section S11 — Facility Plan requires submission of an approvable Facility Plan. The
Facility Plan must be prepared in accordance with WAC 173-240, and must address the
following issues:
1. Comprehensive water quality evaluation.
2. Treatment plant configuration, including treatment of Del Monte flows.
3. Basis for capacity determination.
4. Basis for design of required upgrades.
5. Impacts of treating Del Monte flows, rather than spray field application.
6. Impact of the intermediate clarifier.
7. Documentation for SEPA and SERP determinations.
8. Feasibility of using reclaimed water.
Section S12 — Outfall Evaluation requires an Outfall Evaluation be conducted and report
submitted by January 15, 2005.
Section S13 — Schedule of Compliance requires compliance with State Surface Water
Quality Standards for Copper, Lead, Silver, and Zinc by January 16, 2008 with
requirements for accomplishing a Metals Study by July 15, 2006.
City of Yakima Wastewater Facility Plan - DRAFT 6/7/04
Page 1-7
1.3 Service Area Characteristics
Section 3 of this report describes existing and projected Yakima Regional WWTP service
area characteristics. Table 1-3 summarizes the population estimates for the area through
2024.
Table 1-3
Yakima Wastewater Service and Planning Area Population Projections
Area
Current
Population
Projected
Year 2015
Population
Projected
Year 2024
Population
Planned
Growth
To 2024
Household
Conversion
Factor
Total
Projected
New
Households
Yakima Urban
Service Area
82,8321
100,0002
101,759
18,927
2.503
7,571
Union Gap Urban
Service
Area/Reserve
5,8171
6,655
7,310
1,493
2.556
585
Terrace Heights
Urban Service
Area/Reserve
5,2491
7,3248
9,378
4,1292.559
1,619
Subtotals
93,898
113,979
118,447
24,549
9,775
Yakima Urban
Reserve
4,025
13,81211
31,936
27,911
2.503
11,16411
Totals
97,923
127,791
150,383
52,460
20,939
1. Current Population presented is for 2002 based on extrapolation of population data presented in
2000 Draft Wastewater Facilities Plan and revised population data from the City of Union Gap.
2. 2015 High Population Estimate from the 1998 Amendments Yakima Urban Area Comprehensive
Plan, Adopted November 24,1998, 21,013 assigned to existing Urban Service Area and 10,812
to Yakima Urban Reserve.
3. From the Yakima Urban Area Comprehensive Plan, adopted April 1997.
4. 2000 Population Estimate from the Washington State Office of Financial Management (2003).
5. 2015 Population Estimate assumed an annual increase of 1.23%.
6. From the City of Union Gap Comprehensive Plan, March I999.
7. 1996 Population Estimate from the Terrace Heights Neighborhood Plan, Neighborhood Review
Draft, December 1997.
8. Adjusted from 2016 population estimate from the Terrace Heights General Sewer Plan, March
1998 — high estimate is 14,145.
9. From the Terrace Heights General Sewer Plan, March 1998.
10. From the Yakima Urban Area Comprehensive Plan, adopted April 1997.
11. Anticipated growth within the Yakima Urban Reserve accounted for in the Yakima Urban Service Area or
Union Ga s Urban Service Area.
In accordance with the approved comprehensive plan for each jurisdiction, the projected
build -out population for all areas included in Table 1-3 is approximately 177,500. The
West Valley, Southwest, Terrace Heights, Union Gap, and Southeast areas are expected
to accommodate the majority of this increase in population. Sewage flows from the City
of Moxee may be treated at the Yakima Regional WWTP in the future if their separate
City of Yakima Wastewater Facility Plan - DRAFT 6/7/04 Page 1-8
1.4 Wastewater Flows and Loadings
The historical characteristics of wastewater flow, biochemical oxygen demand (BOD),
total suspended solids (TSS), and ammonia entering the Yakima Regional WWTP were
evaluated in Section 4. The critical design periods selected for evaluation included the
non -canning season (March, when flows are lowest), the irrigation season (August, when
flows are highest), and the Del Monte canning season (September — October, when BOD
loadings are highest). Table 1-4 presents the historical influent Annual Average Flow,
BOD, TSS, and NH4 data for the treatment facility from 2000 through 2002. These
values are the addition of the municipal/industrial flow and loads, and the Del Monte
flows and loads.
Table 1-4
Yakima Total Historical Influent Flows and Loadmgs"2
Year
Flow,
mgd
BOD,
Ib/day
TSS,
Ib/day
NH4, lb/day
2000
11.74
23,865
18,757
1,934
2001
11.71
37,502
22,559
1,959
2002
11.07
37,117
19,082
1,570
2001-2002 Average
11.62
36,311
20,549
1,815
Permit
Limits To Be Determined
-
1 Annual Average flow and load conditions.
2 Flows and loads include contribution from Del Monte.
Table 1-5 shows the projected flows and loadings for the treatment facility. These values
were developed using the population projections presented in Section 3, and baseline unit
flows and loads developed in Section 4. The peak conditions for BOD and TSS are
higher for September through October critical design months, due to Del Monte. Del
Monte loads are assumed to remain constant through the 20 -year planning period.
Table 1-5
Projected Flow and Loadings for the Yakima Regional WWTP
Year
Condition
Flow, mgd
BOD, lb/d
TSS, Ib/d
NH4, lb/d
2004
Baseline Conditions
Annual Average
11.7
26,956
20,094
1,882
Max Month
17.4
32,418
28,964
2,924
Del Monte Conditions
Annual Average
12.1
37,348
21,322
1,887
Max Month
17.8
44,028
30,233
2,934
Peak Hour'
24.8
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05
Page 1-9
Table 1-5
Projected Flow and Loadings for the Yakima Regional WWTP
Year
Condition
Flow, mgd
BOD, Ib/d
TSS, Ib/d
NH4, Ib/d
2009
Baseline Conditions
Annual Average
12.3
29.159
21,736
2,036
Max Month
18.1
35,068
31,332
3,163
Del Monte Conditions
Annual Average
12.6
39,551
22,964
2,041
Max Month
18.5
46,678
32,601
3,173
Peak Hour'
26.1
2014
Baseline Conditions
Annual Average
13.3
32,270
24,055
2,253
Max Month
19.3
38,808
34,674
3,501
Del Monte Conditions
Annual Average
13.6
42,662
25,283
2,258
Max Month
19.7
50,418
35,943
3,511
Peak Hour'
28.2
2019
Baseline Conditions
Annual Average
14.2
35,121
26,180
2,453
Max Month
20.4
42,237
37,737
3,810
Del Monte Conditions
Annual Average
14.5
45,513
27,408
2,458
Max Month
20.8
53,847
39,006
3,820
Peak Hour'
30.1
2024
Baseline Conditions
Annual Average
15.5
38,978
29,056
2,722
Max Month
22.2
46,876
41,882
4,229
Del Monte Conditions
Annual Average
15.8
49,370
30,284
2,727
Max Month
22.6
58,486
43,151
4,239
Peak Hour'
32.9
Build Out
Baseline Conditions
Annual Average
18.5
46,007
34,295
3,213
Max Month
26.7
55,329
49,434
4,991
Del Monte Conditions
Annual Average
18.9
56,399
35,523
3,218
Max Month
27.1
66,939
50,703
5,001
Peak Hour'
39.2
Based on a peaking factor of 2.12 to the baseline annual average flow.
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05
Page 1-10
1.5 Analysis of Existing Wastewater Treatment
Plant
Section 5 summarizes existing design flow and loading capacity, and remaining capacity
for each unit process. Each process area of the Yakima Regional WWTP was further
assessed for current conditions, and for operations and maintenance issues.
The organic treatment capacity of the Yakima Regional WWTP is 53,400 ppd of total
influent BOD corresponding to flows of 14 mgd during peak loading conditions
associated with the canning season. Based on projected future loads, the aeration basins
will need to be expanded in 2018 for adequate treatment of maximum loads during
canning season. The organic capacity of the WWTP during annual average conditions
and no canning loads is 21.5 mgd which will provide sufficient capacity to meet buildout
conditions with no canning loads.
At maximum month non -canning load influent characteristics, the capacity of the WWTP
is projected to be 20.2 mgd. For permitted facility loading, the following values should
be incorporated:
• Average flow (max. month) 20.2 mgd
• BODS loading (max. month) 53,400 ppd
• TSS loading (max. month) 38,600 ppd
• Design population 130,000
0< y
ocip
Table 1-6 summarizes the capacity rating evaluation of each unit process at the Yakima
Regional WWTP, setting capacity at the most restrictive design criteria. The overall peak
hydraulic capacity through the plant based on process limitations and connecting
conveyance structures is approximately 32 mgd. At this flow, the minimum hydraulic
retention time of the existing secondary clarifiers is reached, and successful operation of
the flow diversions at the trickling filter pump station is challenged. The table identifies
capacity of current facilities and required capacity at year 2024 projected loading
conditions.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-11
Table 1-6
Summary of Unit Process Capacity
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05
Page 1-1
Firm Capacity
Year 2024 Flow/Load
Unit Process
Units
Average'
Maximum'`
Month
Peak3
Hour
Average
Maximum
Month
Peak
Hour
Comment
Bar Screens &
Screenings Compactor
mgd
-
-
40
15.5
22.2
32.9
Sufficient capacity.
Grit Removal
mgd
-
-
40
15.5
22.2
32.9
Sufficient capacity.
Flow Measurement
mgd
-
-
60
15.5
22.2
32.9
Sufficient capacity.
Primary Clarifiers
mgd
30.5
63.6
15.5
22.2
32.9
Sufficient capacity.
Trickling Filters
Pumping Station
mgd
-
-
36
15.5
22.2
32.9
Sufficient capacity at future
flows. Not all peak flow
directed to units.
Trickling Filters
mgd
-
11.84
(5.9 each)
-
13.0
11.8
-
Sufficient capacity at current
and future flows. Flows
over 11.8 mgd routed to
aeration basins.
Aeration Basins
mgd
-
15.05
-
16.0
16.3
-
Sufficient capacity at current
flows. Insufficient capacity
for future conditions after
2018.
Aeration Blowers
Scfm
-
-
14,400
-
9,500
-
Blowers have sufficient
capacity for 2024. However,
ongoing problems with
blowers and VFDs limit
their reliability.
Secondary Clarifiers5
mgd
9.2
(18.4
total)
L
-
18.5
(37
total)
16.0
16.3
32.9-
Sufficient redundancy for
WDOE Class II
requirements but high solids
loading with trickling filter
clarifier off line.
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05
Page 1-1
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05
Page 1-13
Firm Capacity
Year 2024 Flow/Load
Unit Process
Units
Average'
Maximum2
Month
Peak3
Hour
Average
Maximum
Month
Peak
Hour
Comment
RAS Pumping
mgd
-
-
32.4
(at 60%
recycle)
-
-
32.9
_
Sufficient capacity for
current peak -hour flows.
Insufficient capacity for
future flow peak hour
conditions at 60% recycle
flow.
WAS Pumping
gpm
-
-
800
82
146
-
Sufficient capacity. Pumps
too large for WAS flows.
Chlorine Contact
Chamber
mgd
19.4
-
58.2
15.5
-
32.9
Sufficient capacity for
current flow conditions.
Insufficient capacity to meet
year 2024 maximum month
conditions.
Chlorination Facilities
lb Ch/d
-
-
1,000
-
-
1,024
Sufficient capacity for
current and 2024 peak flow
conditions.
Outfall
mgd
34.7
32.9
Sufficient capacity for
current and year 2024 peak
flow.
DAF Thickener
lb
TSS/d/sf
-
> 22.66
-
-
22.6
-
Sufficient capacity to serve
to year 2024 conditions.
However, system has no
redundancy provided.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05
Page 1-13
1 Current Average, 11.3 mgd.
2 Current Maximum Month, 16.8 mgd.
3 Current Peak Hour, 24 mgd.
4 Under Del Monte discharge loading conditions.
5 Reliability Class II standards allow secondary clarifier capacity to be 50 percent of design flow.
6 With polymer addition.
Refer to Section 5.4.8 for discussion on digester capacity analysis.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-1
Firm Capacity
Year 2024 Flow/Load
Unit Process
Units
Averages
Maximum2
Month
Peak3
Hour
Average
Maximum
Month
Peak
Hour
Comment
Primary Digesters
HRT (d)
19
13
-
(7)
(7)
-
Needs new digester to meet
additional capacity
requirement for 2024 and to
ensure Class B detention
requirements if existing 70
ft diameter digester goes out
of service.
Secondary Digesters
HRT (d)
7
5
-
(7)
(7)
-
Centrifuges
Gpm
-
240
-
-
-
-
Sufficient capacity to meet
year 2024 maximum month
conditions. However,
centrifuge is near end of its
life and no redundancy is
provided.
1 Current Average, 11.3 mgd.
2 Current Maximum Month, 16.8 mgd.
3 Current Peak Hour, 24 mgd.
4 Under Del Monte discharge loading conditions.
5 Reliability Class II standards allow secondary clarifier capacity to be 50 percent of design flow.
6 With polymer addition.
Refer to Section 5.4.8 for discussion on digester capacity analysis.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-1
The total capacity of the biological system, including the primary clarifiers, trickling
filters, trickling filter clarifier, aeration basins and secondary clarifiers, is 53,400 ppd of
total influent BOD (with corresponding flows of 14 mgd) during maximum month
loading conditions with Del Monte loads. The current plant processes will provide
capacity until 2018, when additional aeration basin capacity is required. This is depicted
on Figure 1-1. This capacity is based on the following qualifications:
• The organic loading capacity is 53,400 ppd BOD and the solids loading capacity
is 38,600 ppd TSS. These loading rates assume maximum month influent loading
from both the domestic contribution as well as Del Monte.
• The maximum month capacity does not include redundancy requirements.
• The evaluation assumes the load to the trickling filter will remain at or below 90
ppd/kcf and the MLSS in the aeration basins will remain at or below 3,000 mg/L.
80000 -
70000
m 60000
c ▪ 50000
0
m
c 40000
▪ 30000
o. 20000
10000
0
Figure 1-1 Plant Organic Capacity
Current Plant Organic
capacity = 53,400 Ib/day
Capacity = 65,400 Ib/day
with new A -Basin
Maximum month
Baseline & Del Monte
projected BOD Toad
Capacity without Trickling
Filters = 25,000 Ib/day
Capacity without Trickling Filter
Clarifier = 40,000 Ib/day
Maximum month Baseline
projected BOD Toad
(without Del Monte)
Year
m
The annual average capacity of the biological system expressed in terms of equivalent
plant flow is approximately 21.5 mgd, which will provide sufficient capacity to meet
buildout conditions. (The annual average projected design flow for buildout conditions is
18.5 mgd.) This capacity is based on the following qualifications:
• At buildout, the projected annual average loadings are 46,000 ppd BOD and
34,300 ppd TSS.
• The annual average capacity does not include redundancy requirements.
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 1-15
The annual average organic capacity of the biological system expressed in terms of plant
flow is much greater than the maximum month capacity (21.5 mgd vs 14 mgd) due to the
significantly lower loads of BOD received during the non -canning season.
1.6 Identification of Selected Wastewater Treatment
Strategies
Section 6 reviewed a wide range of alternatives for expanding the Yakima Regional
WWTP to meet future capacity and regulatory effluent quality requirements. The
following provides a brief description of the recommended alternative for each process
area for the 20 -year planning.
Headworks/Preliminary Treatment - Upgrades and improvements are needed to the
existing grit storage system in the Headworks Building. Repair of the existing storage
hopper is recommended. The opinion of probable cost for the grit storage hopper
upgrades/improvements is $118,000.
Primary Treatment - To provide improved control for distribution of flows and solids to
the primary clarifiers, retrofit of the primary treatment split box is recommended. The
opinion of probable cost for this facility is $428,000.
Trickling Filter System - It is recommended that the existing trickling filter media
remain and current trickling filter operations continue into the future. A second clarifier
dedicated only to trickling filter effluent is not deemed necessary, as the activated sludge
process has adequate capacity for treatment during most of the year without the trickling
filter clarifier, except during maximum month influent loading conditions combined with
Del Monte discharge. There is no redundancy provided with a single clarifier, although
the unit can be serviced during base load periods (no Del Monte discharge) by sending
trickling filter effluent directly to the aeration basins, as was the practice in the past.
Process modeling predicted that, if the trickling filter clarifier was out of service during
current maximum month influent loading combined with Del Monte discharge, the
aeration basin solids concentration would be excessive and solids loading limits on the
secondary clarifiers would be approached.
RAS/WAS Pumping - A new RAS/WAS pumping station, constructed concurrently with
a new secondary clarifier, is recommended. The RAS/WAS pumping station would
provide service to the new secondary clarifier as well as future aeration basins. The
existing RAS/WAS pumping units would remain in service to support the existing
aeration basins and secondary clarifiers. The opinion of probable cost for the new
RAS/WAS pumping station is $1,020,000.
Secondary Clarifier - To improve secondary clarification reliability to Class I criteria, a
third secondary clarifier would be needed. If the trickling filter clarifier is out of service
during peak loading conditions, the aeration basin solids concentration would be
excessive and the solids loading limit on the secondary clarifiers would be approached.
To alleviate this potential situation and improve overall reliability, it is recommended that
an additional secondary clarifier be constructed. Construction of a new secondary
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-16
clarifier is favored over a new trickling filter clarifier, because a new secondary clarifier
would be advantageous during the entire year, whereas the trickling filter clarifier is
needed mainly during canning season loading. During further design efforts, construction
of this clarifier with the capability to operate as both an intermediate trickling filter
clarifier or a secondary clarifier should be investigated. The opinion of probable cost for
the new secondary clarifier is $3,370,000.
Aeration Basins — Future construction of a 1.05 million gallon aeration basin and an
internal anoxic zone to meet capacity requirements prior to 2018 is recommended. The
opinion of probable cost is $2,173,000.
Aeration Blowers - The existing aeration blower system is nearing the end of its service
life and needs to be rehabilitated or replaced. An evaluation was performed to determine
whether to rehabilitate components of the existing blower system or to replace existing
blowers with new units. Installation of new blowers in a new building is the
recommended option. A cost of $1,600,000 is allocated for this project.
Disinfection - Maintaining the existing dual channel gaseous chlorination system
provides a cost effective means for disinfection of the Yakima Regional WWTP
discharge. The opinion of probable cost to maintain the existing disinfection and adding
minor modifications is $343,000. After 2024, the existing chlorination/dechlorination
system will require significant modification and expansion. City policy should ultimately
determine whether the existing systems are replaced with a safer technology, such as UV
disinfection. The project cost for installing UV disinfection is estimated at $2,584,000.
Maintenance Improvement Projects - In addition to the major capital facility projects
identified above, facility improvements throughout the Yakima Regional WWTP were
identified to include safety, reliability, and improved process operation to maintain
compliance with existing state and federal regulations. Table 1-7 identifies these projects
as well as other maintenance -related projects with an opinion of probable cost.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-17
Table 1-7
Maintenance -Related Improvement Projects
Facility Description
Opinion of
Probable Cost
Replacement of Primary Clarifier Collector Mechanisms
$2,275,000
Primary Sludge Pumping Density and Flow Meters
$240,000
Primary Digester Building Lighting Replacement
$49,000
Primary Sludge Pumps Replacement
$100,000
Replacement of Secondary Scum Pumps and Piping
$80,000
Raise Intermediate Degritter Center Wall
$250,000
Trickling Filter Door/Walkway Covers
$85,000
Aeration Basin Diffusers Rehab
$50,000
Refurbish Secondary Clarifier Bull -Gears
$130,000
Replace Secondary Clarifier Skimmer Mechanism/Scum Box
$362,000
Refurbish DAFT Air Compressors/Pipelines
$65,000
Structural Repairs to Aeration Basins 1-3 & Internal Anoxic Zone
$1,173,000
Upgrading Two Existing Secondary Clarifier Launders for Algae
Control and Improved Access
$195,000
Secondary Clarifier Spray Nozzle Installation
$15,000
Grease Receiving Facility
$125,000
Weather Protection for Odor Control Towers
$50,000
Total Opinion of Probable Costs
$5,244,000
Wastewater Treatment Plant Operations, Maintenance, and Support Programs - At
the present time, the number of operations personnel is at an adequate level for the
number of process units and the complexity of the treatment facility. The Wastewater
Manager is required to assess the adequacy of the staffing levels and must determine if
additional staffing is required. There is no indication that additional operations staffing
will be required in the immediate future.
The Maintenance staff at the Yakima Regional WWTP is responsible for preventative and
predictive maintenance of all mechanical, electrical and instrumentation equipment to
ensure the reliability of the treatment facility. As new equipment and additional treatment
process systems are added, additional Maintenance staff may be required. The
recommendations contained in this report would not add sufficient systems or
components to warrant an increase in maintenance staffing in the near future.
Pretreatment Program - The City of Yakima recently adopted a new ordinance to
provide the legal authority for full implementation of the Industrial Pretreatment Program.
The ordinance requires all existing Significant Industrial Dischargers to have a current,
valid wastewater permit (issued either by WDOE or the City of Yakima) in effect as of
the date of full delegation; June 15, 2003. SIU's with permits expiring on or after the
date of delegation are required to immediately submit an application to the City in
accordance with the ordinance. In an on-going process, the City will be converting all
existing wastewater permits issued by WDOE to permits issued by the City.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-18
At present the City lists twenty-seven (27) Significant Industrial Users, of which twenty-
four have permits in place and three are currently in process of obtaining a permit. While
the number fluctuates, there are approximately 530 Minor Industrial Users required to
obtain an Authorization to Discharge. A process is currently underway to notify all
MIU's of the requirement to apply for an Authorization to Discharge.
The level of staffing of the Pretreatment Program is adequate to perform inspection and
sampling of SIU's and MIU's although delegation of the Industrial Pretreatment Program
to the City may necessitate additional administrative or technical personnel. The
implementation of a Fats, Oils and Grease program will significantly increase the
inspection and public interface requirements of the field personnel. One or more
technicians, dedicated to FOG inspection and educational efforts, would be required. It
would be anticipated that one or more field personnel, a vehicle and equipment with
additional administrative assistance may be required to effectively manage the additional
workload. In the immediate future, the Wastewater Manager will evaluate the expected
time frame for issuance of Authorizations to Discharge and implementation of the FOG
program to determine if additional staffing is warranted.
Wastewater Laboratory Staffing and Operation - The present level of laboratory
staffing is adequate to meet the current sample load. If the scope or frequency of process
control, Pretreatment program, or Strong Waste program sampling increase, one or both
of the vacant laboratory positions should be filled. Process control and permit
compliance testing are expected to remain relatively constant under the current permit. As
Pretreatment finalizes parameter lists and sampling frequency plans, near-term laboratory
staffing requirements will come into focus. The implementation of the Pretreatment Fats,
Oils, and Grease program will certainly increase laboratory sample load and warrant the
hiring of a laboratory technician.
1.7 SCADA and Electrical Power
Section 7 summarizes existing power distribution components and SCADA components
at the Yakima Regional WWTP, and provides options and cost projections for possible
upgrades.
1.7.1 Power Distribution System Assessment
The electrical power distribution system operates with good reliability and appropriate
voltage levels throughout the treatment facility. Some areas of non-selective overcurrent
protection exist in the plant, but do not appear to result in exposure to simultaneous
outage of vital components. Overvoltage protection is limited, but has not resulted in
known cases of failure or component damage.
In general, capacity for added standby power load at each motor control center is limited
and additions will require evaluation on a case-by-case basis. Physical space for
additional units to serve new loads is very limited in many cases and may require sub -
feeding new distribution or motor control equipment for these loads.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-19
EPA Class I & II reliability requirements for the power distribution system specify "vital"
process equipment that must have redundant power distribution. EPA design criteria
requires that the quantity of process equipment defined as "vital" must exceed the
quantity of that equipment that is necessary to perform the required function by a
minimum of one unit.
Normal Power - Substation 4 is currently served by a single normal power transformer.
Furthermore, the transformer is "unit substation style" and, if replacement is required as a
result of a failure, it may take several weeks before it is delivered to the site once ordered.
Since Substation 4 serves process areas that are required for the operation of the plant, it
appears that the EPA reliability requirements may not be met at the present time.
EPA design criteria requires that the quantity of process equipment defined as "vital"
must exceed the quantity of that equipment that is necessary to perform the required
function by a minimum of one unit. While it appears that the quantity of trickling filter
pumps meets this requirement, all four are electrically connected to the same power
distribution bus, making this bus a single point of failure. This situation does not meet
the EPA design criteria.
Standby Power - Two key systems that were evaluated with respect to standby power
requirements were the aeration blowers and the trickling filter pump station.
Providing standby power capacity for aeration blower operation is required under EPA
Class I & II and WDOE requirements in order to keep the "biota" alive when normal
power experiences an extended outage. The addition of standby power to the aeration
blower would require replacement of the existing engine generator with a larger unit
(800-1200kW) or providing a second unit (600-800kW) at the aeration blower area. The
projected cost for adding standby power capability to the aeration blower operation by
providing a separate engine generator and a standby power distribution switchboard in the
aeration blower area is estimated to be $469,000.
The addition of standby power to the trickling filter pump station loads appears necessary
to maintain treatment quality and to preserve the "biota" during a normal power failure.
The cost projection is $178,000. The addition assumes that the trickling filter loads can
be served from the existing engine -generator, and includes splitting the bus in the pump
station MCC and two independent feeds to the two buses to meet EPA/WDOE reliability
requirements.
City of Yakima Wastewater Facility Plan -- DRAFT 8/12/05 Page 1-20
1.7.2 SCADA System
Concerns over technical support provided for the existing TESCO electronic controllers,
long system reaction time, and difficulty in developing reports using historical data stored
in the SQL Server database are some of the issues identified by facility personnel or
during reviewing of existing documentation and onsite conditions. Three options have
been considered for the existing SCADA system:
• Option 1 — Maintain and expand existing SCADA system with like components.
• Option 2 — Replace major SCADA components as part of a single project.
• Option 3 — Incremental major SCADA system component replacement.
Based on discussions with City personnel and operations staff, Option 2, major SCADA
component replacement, is the recommended approach for the SCADA system.
This option involves replacing the major SCADA system components at the treatment
facility and the remote lift stations as part of a single project. Replacement would include
PLCs, Computer hardware and software, HMI software, and historical data logging
software. This wholesale replacement would also require installation of new fiber optic
backbone communications and associated peripherals between several buildings on site.
The projected cost associated with major SCADA component replacement is $930,000.
1.8 Gas Utilization and Cogeneration
Section 8 examines the options for the use of methane gas produced in the anaerobic
digesters and makes recommendations for future utilization of the gas. The following is a
summary of the recommendations:
• Cogeneration as an option for digester gas utilization is not cost effective. It is
recommended to continue utilizing digester gas in boilers for heating the digesters
and buildings.
• The digester gas collection piping is over 20 years old and will need to be upsized
for the design gas production. An estimated cost for improvements is $236,000.
• When additional heating demands warrant, a new boiler should be installed.
• Fuel oil should be continued to be used as the backup fuel for the existing boilers.
Installation of natural gas piping on the site should be considered in the future.
1.9 Biosolids Management
Section 9 summarizes the Yakima Regional WWTP biosolids management program and
provides recommendations for continued beneficial use of the City's treated biosolids.
The Yakima Regional WWTP solids treatment process consists of thickening, anaerobic
digestion, and dewatering. At the present time, the treatment facility produces a Class B
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-21
biosolids product which is land applied at the Natural Selection Farms Beneficial Use
Facility (NSFBUF), a private land application operation in Yakima County.
The existing solids processes have adequate capacity for the current solids production;
however, some of the processes do not have adequate standby capacity in the event of an
equipment failure. In addition, future increases in solids quantities may require additional
process capacity. Based on the capacity evaluation and standby requirements presented in
Section 5, the following processes are recommended for expansion:
• WAS Thickening
• Anaerobic Digestion
• Dewatered Cake Storage
• Centrate Equalization
• Dewatering
Dissolved Air Flotation Thickening - The existing DAFT unit has adequate capacity
through the 2024 design period; however, the single DAFT unit has no standby
capability. If the existing unit was out of service, compliance with biosolids stabilization
regulations would be compromised. Therefore, it is recommended that the City install a
second 45 foot diameter DAFT unit. While only one unit would be operated at a time,
operation should be alternated to ensure that both units stay in working order. It is
recommended that the existing dry polymer feed system be dedicated to DAFT treatment.
The estimated project cost for a new DAFT system is $2.0 million.
Anaerobic Digestion - Anaerobic digestion systems are typically designed to meet
detention requirements with one primary tank out of service, which allows tank cleaning
or maintenance. Based on maximum month solids projections, if the large primary
digester (1.0 MG) is taken out of service, the remaining tankage (primary and secondary)
can not provide 15 days of detention to meet Class B pathogen criteria. If secondary
digesters are not used as backup primary capacity, the primary digester requirement
increases to 1.3 MG at 2024 conditions. The recommended option provides adequate
primary tankage to support primary digestion requirements with the existing large (1.0
MG) primary tank out of operation. This option requires a new, 1.3 MG primary
digestion tank, equipped with heating and mixing. The estimated project cost for a new
anaerobic digester is $5.4 million.
Dewatered Cake Storage - Dewatered cake from the centrifuges is discharged into
trucks and hauled to the NSF BUF. Plant staff has indicated that inclement weather can
interfere with hauling operations during the winter. Dewatered cake storage would
provide temporary on-site storage for the dewatered cake during these periods. The
proposed cake storage facility will provide three weeks of storage at 2024 average
conditions and enclosed storage for up to five trailers. The estimated project cost for a
cake storage facility is $1.9 million.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-22
Centrate Equalization - The Yakima Regional WWTP currently operates a single
centrifuge approximately two days per week to dewater digested solids and returns
centrate to the head of the plant for treatment in the liquid process. Based on the current
centrifuge operation, large quantities of centrate are produced in a relatively short time.
Centrate is currently equalized through the south lagoon; however, if this lagoon is
decommissioned, the city must either provide a new equalization facility, treat the
centrate prior to its return, or operate the centrifuges for a longer period at a lower feed
rate, reducing the rate of centrate production.
Of the three options, equalization of the centrate is recommended. The estimated project
cost for a centrate equalization facility is $1.5 million.
Dewatering - The current dewatering facility at the Yakima Regional WWTP has a
single operable centrifuge, installed in 1992. No standby dewatering equipment is
available. The three dewatering alternatives selected for further evaluation are as follows:
• Dewatering Alternative 1 — Replace inoperable centrifuge, add new dewatering
polymer system, provide odor control for
dewatering area
• Dewatering Alternative 2 — Construct new dewatering facility with truck load
out, relocate existing operable centrifuge, install
new second centrifuge
• Dewatering Alternative 3 - Construct new dewatering facility with truck load
out, install new screw press dewatering.
Alternative 2 — New Centrifuge Dewatering Building — is the recommended option. This
alternative addresses the staff's concerns with the existing dewatering facility and
provides back up capability. However, its present worth of $13.44 million is more than
20 percent greater than the cost of Alternative 1 — Replace Centrifuge. Consequently, if
funds are not available to construct a new dewatering facility, Alternative 1 should be
considered.
Alternative 1 — Replace Centrifuge — is the least expensive dewatering alternative. While
this alternative provides back up dewatering, it does not address all of the concerns with
the existing dewatering system. The tight layout of the existing equipment makes
maintenance access difficult for the centrifuges and the dewatered cake conveyance
system. In addition, this alternative does not modify the open cake load out area, which
may be a source of odors.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-23
Class A Treatment Alternatives - Alternatives to enhance the biosolids to Class A to
allow public use were considered including advanced digestion and heat drying. While
there may be some advantages to producing Class A biosolids, the cost of producing
Class A biosolids is high. Due to continuing developments in treatment technology and
possible changes in the availability of sites for land application, these options should be
re-evaluated if the decision to move to a Class A process is deferred to a future date.
1 .10 Analysis of Existing Wastewater Collection
Facilities
Section 10 (which was not updated from the 2000 Draft Wastewater Facilities Plan)
identifies the existing lift stations, pumping station, forcemains, and sanitary sewer
conveyance facilities for the City of Yakima sanitary sewer system. The infiltration and
inflow into the system; the current program for sewer system rehabilitation; and safety,
reliability, and efficiency issues are presented.
The evaluation of infiltration and inflow into the City of Yakima sewerage system
conducted for the 2000 Draft Wastewater Facilities Plan concluded that these extraneous
flows generally comply with the Environmental Protection Agency criteria for
determination as non -excessive. During the spring and summer 2000, an increase in
wastewater flow over the previous 3 -years of record was observed at the Yakima
Regional WWTP. Upon investigation by City staff, extraneous flow was found to be
entering the sewerage system from individual side laterals. The City's current program of
systematically identifying sources of infiltration and inflow and incorporating
rehabilitation of the collection system into the annual operation and maintenance program
should be continued.
In consideration of the objectives of a mandatory preventative maintenance program for
the collection system to: anticipate problem areas and initiate action before any problems
occur; to reduce potential claims for damages resulting from system failures; and in
avoidance of future liability costs, an increase of 6 full-time staff positions for the
Wastewater Collection System unit is recommended.
An evaluation of the collection system is currently being performed. This evaluation will
include updating the City's GIS database, implementing a flow monitoring program to
determine capacities and influences of infiltration and inflow, and hydraulic modeling of
the pipe system.
1.11 Identification of Selected Wastewater Collection
Strategies
Section 11 (which was not updated from the 2000 Draft Wastewater Facilities Plan)
looks at the existing baseline and future buildout interceptor replacement projects
resulting from population growth within the Yakima Urban Area. The impact of growth
within the Yakima Urban Reserve area on the interceptor system is also identified. New
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-24
interceptors within the Yakima Urban Reserve are described. Cost estimates developed
for the 2000 Draft Wastewater Facilities Plan were inflated to year 2004 for this update.
Existing System Deficiencies - The analysis of the existing collection system identified
an opinion of probable cost of $783,000 to correct existing system flow limitations to
meet current conditions. Correction of existing system deficiencies is mandatory to
comply with the Four Party Agreement.
Buildout System Deficiencies - The opinion of probable cost to meet system flow
limitations for build -out within the Yakima Urban Area was $2,107,000, or $1,324,000 in
addition to the correction of existing system deficiencies. Providing system capacity to
meet population growth within the Yakima Urban Area is mandatory to comply with the
Four Party Agreement.
New Interceptors/Trunk Sewers - The opinion of probable cost for new interceptors
and trunk sewers to provide sewer service within the Yakima Urban Area and the Yakima
Urban Reserve area is $30,591,400. The cost of the new interceptors and trunk sewers
has been allocated to each area based upon the ultimate buildout population. The Yakima
Urban Area assignment of opinion of probable cost ($9,177,400) is 30 percent (15,000
people), and the Yakima Urban Reserve area assignment of opinion of probable cost
($21,414,000) is 70 percent (35,000 people). Those costs attributed to providing system
capacity to meet population growth within the Yakima Urban Area are mandatory to
comply with the Four Party Agreement.
Impact of Growth in the Urban Reserve - The construction of the new interceptors and
trunk sewers into the Yakima Urban Reserve area will increase flows in the existing
wastewater collection system. The opinion of probable cost of these impacts is
$10,691,000. The assignment of probable cost to the Yakima Urban Area (30 percent) is
$3,207,200 and the assignment to the Yakima Urban Reserve area (70 percent) is
$7,483,800. Again, system capacity attributed to population growth within the Yakima
Urban Area is mandatory to comply with the Four Party Agreement.
Miscellaneous Collection System Projects - With the increased staffing and equipment
required for the Sewer Collection Program, and with the new requirements for the
mandatory Stormwater Utility, additional shop and administrative facilities will be
needed. An opinion of probable cost for expansion at the current site by purchase of
adjacent properties and construction of new vehicle storage and administrative facilities is
$3,676,000.
Two additional projects which have been recommended for the Sewer Collection
Program include the development of a computer model to provide an improved analysis
of the collection system, and an in -system flow monitoring program to identify existing
basin flows. The opinion of probable costs for these two additional projects is $400,000.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-25
1.12 Financial Planning/Implementation
Section 12 presents a general overview of past rates analyses, financial policies of the
City of Yakima's Wastewater Utility and an overview of the revenue requirements
associated with completion of the projects outlined herein are provided. In addition,
project implementation costs are evaluated and potential revenue alternatives that may be
available to the City are discussed.
1.12.1 Wastewater Treatment Plant Improvements
Recommended improvements to the Yakima Regional WWTP include a variety of
projects totaling an estimated $41 million in regulatory, capacity upgrade, health and
safety features and regular renewal and replacement projects over the 20 -year planning
horizon with approximately $17.5 million in improvements scheduled for the 0-6 year
near term capital improvement program. Wastewater treatment plan improvements are
identified in Table 1-9. Estimated costs, relative schedules and the primary reason for
installation or upgrade are indicated. Indication of the reason for the upgrade should be a
primary determination in deciding the type of funding to be utilized for each project.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-26
Table 1-9
Wastewater Treatment Plant
Recommended Improvement Projects
Project
Number
Facility Description
Opinion of
Probable Cost
0-6
Year
7-12
Year
13-20
Year
Primary Project
Purpose
1
Retrofit Primary Split Box
$428,000
$428,000
Renewal/Safety
2
Replacement of Primary Clarifier Collector Mechanisms
$2,275,000
S2,275,000
Renewal Safety
3
Trickling Filter Door/Walkway Covers
S85,000
$85,000
_
Renewal/Safety
4
Aeration Basin Diffusers Rehab
S50,000
$50,000
_
Renewal/Safety
5
Structural Repairs to Aeration Basins 1-3 & Internal Anoxic Zone
$1,173,000
$1,173,000
Renewal/Growth
6
New Aeration Basin/Anoxic Zone
S2,173,000
$2,173,000
_
Growth
7
New Blowers in New Blower Building
$1,600,000
$1,600,000
Renewal
8
Refurbish Secondary Clarifier Bull -Gears
$130.000
$130,000
Renewal/Safety
9
Replace Secondary Clarifier Skimmer Mechanism/Scum Box
$362,000
$362,000
Renewal/Safety
10
Upgrade Two Existing Secondary Clarifier Launders for Algae
Control and Improved Access
$195,000
$195,000
Renewal/Safety
11
Secondary Clarifier Spray Nozzle Installation
$15,000
$15,000
Renewal/Safety
12
New Secondary Clarifier
$3,370,000
$3,370,000
Growth
13
project deleted
-
-
-
14
Retrofit Grit Storage Hopper
$118,000
$118,000
Renewal/Safety
15
Primary Sludge Pumping Density and Flow Meters
$240,000
S240.000
_
Renewal/Safety
16
Primary Digester Building Lighting Replacement
$49,000
$49,000
_
Renewal/Safety
17
Primary Sludge Pump Replacement
$100,000
$100,000
Renewal/Safety
18
Raise Intermediate Degritter Center Wall
$250,000
$250,000
Renewal/Safety
19
Replacement of Secondary Scum Pumps and Piping Modification
$80,000
$80,000
Renewal/Safety
20
New RAS/WAS Pumping Station for new Secondary Process Units
$1,020,000
$1,020,000
Growth
21
Refurbish DAFT Air Compressors/Pipelines
$65,000
$65,000
_
Renewal/Safety
22
New DAFT Unit
$2,043,000
$2,043,000
Regulatory
23
New Centrifuge and Polymer System
$3,103,000
$3,103,000
Regulatory/Growth
24
New Centrifuge to replace Existing Unit (In 2014)
$1,196,000
$1,196,000
Renewal/Safety
25
Centrate Equalization Tankage
$1,515,000
$1.515,000
Renewal
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05
Page 1-27
Table 1-9
Wastewater Treatment Plant
Recommended Improvement Projects
Project
Number
Facility Description
Opinion of
Probable Cost
0-6
Year
7-12
Year
13-20
Year
Primary Project
Purpose
26
Closure of South Lagoon Without Removal
S 111,000
$111,000
Regulatory
27
Replacement of Digester Gas Piping, Valves and Flow Meters
$236,000
$236,000
Renewal/Safety
28
Replacement of Waste Gas Flare
$68,000
$68,000
_
Renewal/Safety
29
New Boiler/Hot Water
$245.000
$245.000
Growth
30
Grease Receiving Facility
$125,000
$125,000
Regulatory/Safety
31
New Primary Digester
$5,384,000
$5,384,000
Growth
32
Thermophilic Digestion (TPAD)
$5,174,000
$5,174,000
Regulatory
33
Enclosed Trailer and Cake Storage Facility
$1,926,000
$1,926,000
Safety
34
Administration Building Modifications
$500,000
$500,000
Growth
35
Laboratory/Instrumentation
5210.000
$90,000
$85,000
$35,000
Renewal/Safety
36
Weather Protection for Odor Control towers
550.000
$50,000
Renewal/Safety
37
Odor Control lmprovements
$1,112,000
$1,112,000
Regulatory/Safety
38
Standby Power Addition to Trickling Filter Pump Station and
Aeration System
$647,000
$647,000
Growth
39
SCADA System Replacement
$930.000
5930,000
Regulatory
40
UV Disinfection
52,584,000
$2,584,000
Renewal/Safety
Total WWTP Opinion of Probable Costs
$40,937,000
$17,506,000
$15,453,000
$7,978,000
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05
Page 1-2
1.12.2 Projection of Facility Improvement Financing
The improvements proposed in Section 12 can generally be divided into three primary
categories: Mandated improvements by federal and state agencies, mandated
improvements that are related to system renewal, safety and/or efficiency and capacity
related improvements related to growth. Mandated projects are those which result from
new federal and/or state regulations. Mandated renewal and replacement projects are the
replacement of existing and worn out (depreciated) facilities to comply with federal or
state laws, rules, regulations and requirements or those projects needed to meet current
reliability and safety standards. Growth related facilities are related to system expansion,
system upgrades, or needed to meet the provisions of the "Four Party Agreement" that are
considered to be mandatory. Tables 1-10, 1-11, and 1-12 present the recommended
projects for the 0-6, 7-12 and 13-20 time frames based on whether they are mandate by
state and federal regulations or renewal, safety, operational and efficiency issues; or
growth related.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-29
Table 1-10
0 — 6 Year Priority Imarovements
Project
Facilitytion
Description p
Opinion of
Probable Cost
Mandatory 1
2
Growth
Regulatory
Renewal/
Safety,
39
SCADA System Replacement
$930,000
$930,000
7
New Blowers in New Blower Building
$1,600.000
$1,600,000
23
New Centrifuge and Polymer System
53.103,000
$3,103,000
22
New DAFT Unit
$2.043,000
52,043.000
38
Standby Power Addition to Trickling Filter Pump Station, Aeration
System, and New RAS/WAS Pump Station
$647,000
$647,000
25
Centrate Equalization Tankage
$1,515,000
$1,515,000
4
Aeration Basin Diffusers Rehab
$50,000
$50,000
27
Replacement of Digester Gas Piping, Valves and Flow Meters
$236,000
$236.000
30
Grease Receiving Facility
$125,000
5125,000
35
Laboratory/Instrumentation
$90,000
$90,000
40
UV Disinfection
$2,584,000
S2.584.000
17
Primary Sludge Pump Replacement
$100,000
$100.000
33
Enclosed Trailer and Cake Storage Facility
51.926,000
$1,926.000
36
Weather Protection for Odor Control towers
$50,000
550.000
3
Trickling Filter Door/Walkway Covers
$85,000
$85,000
37
Odor Control Improvements
$1,112,000
$556,000
$556.000
19
Replacement of Secondary Scum Pumps and Piping Modification
$80,000
$80.000
20
New RAS/WAS Pumping Station for new Secondary Process Units
$1,020,000
$1,020,000
10
Upgrade two Existing secondary Clarifier Launders for Algae Control
$195,000
$195,000
11
Secondary Clarifier Spray Nozzle Installation
$15,000
$15,000
Subtotal Treatment Facility Improvements
517,506,000
$9,872,000
$5,967,000
$1,667,000_
Collection System Model and Monitoring
$400,000
$400,000
Collection System Facilities (Table 11-11)'
5783.000
$783,000
Collection Facility Improvements (Table 11-13 & 11-15)'
$1,324,000
$1,324,000
City kima Wastewater Facility Plan — DRAFT 8/12/05
Pa '0
Project
Number
Facility Description
p
Opinion of
Probable Cost
Mandatory 1
,
Growth `
Regulatory
Renewal/
Safety
Collection Facility Improvements (Table 11-14) 20%4
$6,118,000
$1,835,400
$4,282,600
Subtotal Collection Facility Improvements
$8,625,000
$2,235,400
$2,107,000
$4,282,600
TOTAL TREATMENT AND COLLECTION
$26,131,000
$12,107,400
$8,074,000
$5,949,600
1
Compliance with federal/state laws and regulations. and the Four Party Agreement
System Improvements to accommodate growth related issues.
3 Table referenced is provided in the Attachment to Section 11 (multiplied by an inflation factor of 1.1283)
Costs shown are 30% Mandatory, 70% Growth
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-31
Table 1-11
7 —12 Year Priority Improvements
Project
Number
Description
Opinion of
Probable Cost
Mandatory'
o
Growth -
Regulatory
Renewal/
Safety
1
Retrofit Primary Split Box
$428,000
$428.000
2
Replacement of Primary Clarifier Collector Mechanisms
$2,275,000
$2.275,000
5
Structural Repairs to Aeration Basins 1-3
$1,173,000
5750,000
S423,000
8
Refurbish Secondary Clarifier Bull -Gears
S130,000
S130,000
9
Replace Secondary Clarifier Skimmer Mechanism/Scum Box
$362,000
$362.000
12
New Secondary Clarifier
$3.370,000
$3.370,000
14
Retrofit Grit Storage Hopper
$118,000
$118,000
_
16
Primary Digester Building Lighting Replacement
$49.000
$49.000
21
Refurbish DAFT Air Compressors/Pipelines
$65.000
$65,000
31
New Primary Digester
$5,384,000
$5,384,000
18
Raise Intermediate Degritter Center Wall
$250,000
S250.000
24
New Centrifuge to replace Existing Unit (In 2014)
51,196,000
$1,196,000
28
Replacement of Waste Gas Flare
$68,000
$68.000
34
Administration Building Modifications
$500,000
$500,000
35
Laboratory/Instrumentation
$85,000
$85,000
Subtotal Treatment Facility Improvements
$15,453,000
$0.00
$5,776,000
$9,677,000
Collection Facilities (Table 11-15 inc. only) '
$8,584,000
$2,575,200
56,008,800
Maintenance Building
$3,676,000
S2,940,800
5735,200
Collection System Facilities (Table 11-14 (40%) 3
$12,237,000
$3.671,100
$8,565,900
Subtotal Collection Facility Improvements
$24,497,000
$9,187,100
$15,309,900
TOTAL TREATMENT AND COLLECTION
$39,950,000
$9,187,100
$5,776,000
$24,986,900
Compliance with federal/state laws and regulations, and the Four Party Agreement
System Improvements to accommodate growth related issues.
3 Table referenced is provided in the Attachment to Section 11 (multiplied by an inflation factor of 1.1283) - Costs shown are 30% Mandatory, 70% Growth
City kima Wastewater Facility Plan — DRAFT 8/12/05
Par '2
Table 1-12
13 — 20 Year Priority Improvements
Project
Number
Facili tY Descri hon
p
Opinion of
Probable Cost
Mandatory 1
,
Growth `
Regulatory
Renewal/
Safety
6
New Aeration Basin/Anoxic Zone
$2,173,000
$2,173,000
15
Primary Sludge Pumping Density and Flow Meters
$240,000
$240,000
26
Closure of South Lagoon Without Removal
$111,000
$111,000
29
New Boiler/Hot Water
$245,000
$245,000
32
Thermophilic Digestion (TPAD)
$5,174,000
$5,174,000
35
Laboratory/Instrumentation
$35,000
$35,000
Subtotal WWTP Opinion of Probable Costs
$7,978,000
$5,285,000
$275,000
$2,418,000
Collection Facility Improvements (Table 11-14) 40%3
$12,237,000
$3,671,100
$8,565,900
Subtotal Collection Facility Improvements
$12,237,000
$3,671,100
$8,565,900
TOTAL TREATMENT AND COLLECTION
$20,215,000
$8,956,100
$275,000
$10,983,900
1
Compliance with federal/state laws and regulations, and the Four Party Agreement
System Improvements to accommodate growth related issues.
3 Table referenced is provided in the Attachment to Section 11 (multiplied by an inflation factor of 1.1283) - Costs shown are 30% Mandatory, 70% Growth
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05
Page 1-33
Table 1-12A shows the percentages of costs for Mandatory and Growth related projects.
As indicated in the table the greater percentage of costs for the Wastewater treatment
plant are mandatory whereas the greater percentage of costs for the collection system are
growth related. Total Treatment and collection costs are equally divided between
mandatory and growth related improvements.
Table 1-12A
% of Total Costs by Primary Project Purpose
Treatment and Collection
Project costs
Mandatory I
Growth 2
Regulatory
Renewal/
Safety
Total WWTP Opinion of Probable Costs
$40,937,000
$15,157,000
$12,018,000
$13,762,000
66%
34%
Total Collection Facility Improvements
$45,359,000
$15,093,600
$2,107,000
$28,158,400
38%
62%
TOTAL TREATMENT AND COLLECTION
$86,296,000
$30,250,600
$14,125,000
$41,920,400
51%
49%
Compliance with federal/state laws and regulations, and the Four Party Agreement
2 System Improvements to accommodate growth related issues.
1.12.3 Projected Budget and Recommendations
Table 1-13 presents a historical and projected budget for the City of Yakima Wastewater
Utility. This simplified budget overview is intended to provide order of magnitude costs
and assist the City in its on-going decision making, project prioritization and budgeting.
More detailed consideration of available funds and revenue requirements occurs bi-
annually in the City's established rate review and cost -of -service analysis and periodic
review and adjustment of connections charges. As indicated in Table 1-13 and discussed
in Section 12, the 2003 bond issue provides a significant source of revenue for immediate
improvements to the wastewater treatment plant. Long term financing strategies will
include continuing to apply for grant and low interest funding where appropriate and
maintaining current and equitable connection charges and fees that growth to finance
required system expansions.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 1-34
Operating Revenues
Operating Expenses:
Operating Expense
Depreciation Expense
In -lieu Tax
Other Taxes
Total Operating Expenses
Net Operating Income
Other Income:
Gain (Loss) on Sale of Assets
Interest Income/(Expense) net(4)
Non-utility Income(5)
Miscellaneous
Total Other Income
Total Income
Available for Debt Service
on First Lien Bonds (1)
"st Lien Debt Service
:overage
Available for Debt Service
on Second Lien Bonds (2)
Second Lien Debt Service(3)
SRF Loan
1996 Bonds
1991-1998 ref
1998 new
2003 Bonds
Projected
Actual
2002
511,061,537
55,989,079
52,725,912
51,322,373
5536,125
$10,573,489
5488,048
50
(5233,978)
$15,625
50
Table 1-13
Wastewater Utility Budget
Estimated Budget
2003 2004 2005
2006 2007
511,568,180 512,862,248 512,926,559 S12,991,192 513,445,884
$5,997,500 56,538,711 56,669,485
S2,951,613 $2,866,686 $2,671,651
51,401,362 51,589,145 51,620,928
5629,872 5648,758 5661,733
510,980,347 511,643,300 511,623,797
5587,833 51,218,948 51,302,762
SO
(540,819)
5301,496
SO
50 SO
(537,992) (514,942)
5320,064 S407,064
50 SO
56,836,222
53,079,581
51,661,451
5678,276
S12,255,531
5735,661
SO
510,058
5407,064
$0
$7,041,309
53,412,512
51,711,295
5698,625
$12,863,740
5582,143
50
S35,058
5407,064
SO
(5218,353)
5269,695
S4,317,980
5273,653
15.78
5260,677
5848,510
55,201,485
5276,075
18.84
$282,072 5392,122 5417,122 5442,122
$1,501,020 51,694,884 $1,152,783 51,024,265
$5,956,851 55,987,463 $5,893,815 56,148,072
50 50 SO $0
n/a n/a n/a n/a
54,044,327 $4,925,410 55,956,851 55,987,463 S5,893,815 56,148,072
5324,791
S363,875
5609,647
50
50
5162,396
5361,915
$505,052
50
50
SO
5369,360
5504,868
50
51,292,472
50
$365,585
5508,722
50
$1,352,030
$0
5366,035
5507,254
SO
51,349,430
50
S370,285
5500,253
SO
$1,349,180
51,298,313 51,029,363 52,166,700
Coverage 3.12 4.78 2.75
(1) Net Revenues as defined in the Bond Ordinance.
(2) Net Revenues less First Lien debt service.
(3) Excludes Public Works Tnist Fund Loans.
(4) Includes interest expense on PWTF Loan but not parity debt interest.
(5) Represents operating contribution for debt service from Union Gap and Terrace Heights.
52,226,337
2.69
52,222,719 52,219,718
2.65 2.77
Notes:
All Operating expenses except depreciation (depreciation includes new projects as disclosed herein) are increased 2.0% for 2005,
2.5% for 2006, and 3.0% for 2007.
Operating revenues are increased .5% for 2005 and 2006, 3.5% for 2007
Interest is increased 523,050 for 2005 and for 2006and 2007 525,000
rce: City of Yakima
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 1-35
SECTION 2
DISCHARGE AND TREATMENT REQUIREMENTS
2.1 Introduction
This section presents a review of regulatory and permitting issues that may influence
wastewater facility planning in Yakima. Among the issues considered in this section are
surface water quality standards, the National Pollutant Discharge Elimination System
(NPDES) permit, which governs effluent discharged from the Yakima Regional
Wastewater Treatment Plant (WWTP) to the Yakima River, future basin -wide water
quality issues, facility reliability classification, and additional issues impacting WWTP
planning.
In order to assess current issues, contact was made with the Washington Department of
Ecology (WDOE), the agency responsible for issuing NPDES waste discharge permits for
the United States Environmental Protection Agency (USEPA) in the State of Washington.
The purpose of the contact with WDOE was to identify current and anticipated future
NPDES permit, and other regulatory requirements, that may affect the future of the
wastewater utility. The Yakima Regional WWTP currently operates under NPDES permit
number WA -002402-3, issued April 30, 2003. The permit will expire on June 1, 2008.
A copy of the NPDES Permit is included in Appendix A.
Table 2-1 presents a summary of the regulatory and permitting issues presented in this
Section, with the status of each issue as it applies to the Yakima Regional WWTP, and
the level of concern regarding the issue. Treatment plant NPDES discharge permit issues
are included, as are related regulatory issues, which may influence planning. Issues with
a high level of concern are likely to require action in the near future (within 10 years); a
moderate level of concern indicates that regulations may affect the operation of the
treatment facility, but action is not likely to be required in the near future (beyond 10
years) or has a relatively minor impact on wastewater treatment facilities; a low level of
concern indicates that the issue has little effect on the operation of the wastewater
treatment facilities (beyond 20 -years). The paragraphs that follow in this Section explore
each category of potential regulatory influence in greater detail.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-1
Table 2-1
Summary of Regulatory and Permitting Issues
Regulatory
Issue/Parameter
Issues and Current Status
NPDES
Permit
Limits'
Importance
to Planning
Effluent Discharge
Wastewater Treatment Facility permitted flow to be
determined and will be established when the Final
Facility Plan is approved by DOE.
30 mg/L average monthly, 45 mg/L average weekly;
average monthly value may not exceed 15% of the
average influent concentration or 30 mg/L, whichever
is more stringent.
No current limitations. Concentration and load limits
are anticipated in 10 to 15 years. Phosphorus is likely
to be regulated
No current limitations. Concentration and load limits
are possible in 10 to 15 years.
No load limit. Concentration limit (4.16 mg/I
monthly ave., 12.3 tng/I daily max).
Residual limit (0.012 mg/1 monthly ave., 0.029 mg/I
daily max).
6.0 to 9.0
Fecal coliform limits (200 organisms/100 ml monthly
geometric mean, 400 organisms/I00 ml weekly
geometric mean) May be modified to e -coli in future.
Y
C
N
N
C
C
Y
C
High
Moderate
Moderate
Moderate
High
High
High
High
WWTP Flow
BOD and TSS
Phosphorus
Total Nitrogen
Ammonia Nitrogen
Chlorine Residual
pH
Bacteria
Metals
Interim Limit: 9.84 ug/L (average monthly), 14.36
ug/L (max daily)
Final Limit: 6.71 ug/L (average monthly), 9.80 ug/L
(max daily)
3.96 ug/L (average monthly), 5.77 ug/L (max daily)
2.18 ug/L (average monthly), 3.17 ug/L (max daily)
Interim Limit: 70.35 ug/L (average monthly), 95.82
ug/L (max daily)
Final Limit: 45.70 ug/L (average monthly), 66.70
ug/L (max daily)
Y
Y
Y
Y
High
Moderate
Moderate
High
Total Copper
Total Lead
Total Silver
Total Zinc
Biomonitoring
Whole effluent toxicity testing required for acute and
chronic toxicity.
Y
High
Infiltration/Inflow
Collection system rehabilitation projects have reduced
1&I. Infiltration is related to seasonal use of irrigation
system in the community.
S
High
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 2-2
Table 2-1
Summary of Regulatory and Permitting Issues
Regulatory
Issue/Parameter
Issues and Current Status
NPDES
Permit
Limits'
Importance
to Planning
Biosolids
Biosolids management must meet 1) RCW 90.48.080
& Water Quality Standards; 2) applicable sections of
40 CRF Part 503 & Chapters 173-308 WAC,
"Biosolids Management"; 3) applicable sections of
Chapter 173-304 WAC, "Minimum Functional
Standards for Solid Waste Handling."
S
High
Virus Control
May have stricter requirements in the future as
analytical methods improve.
N
Moderate
Effluent
Several segments of the Yakima River are listed on
the State 303(d) list for TMDL development for
temperature, pH, sediments, Fecal Coliform,
turbidity, flow, and a variety of pesticides.
EPA may enact rules impacting the use of chlorine as
a disinfectant within the next 10-15 years.
WDOE Land Application Guidelines apply to
reclamation and reuse. Effluent reuse may be a
management tool for load diversion from the Yakima
River.
N
N
N
Moderate
Moderate
Moderate
TMDL and Watershed
Planning
Chlorine Byproducts
Effluent Reclamation and
Reuse
Treatment Plant
Regulations apply to VOCs, H2S, C12; but not likely
to be considered major source.
Clean Air Act Section 112r Risk Management Plan
(RMP) requirements have a resubmission deadline of
June 21, 2004..
Yakima County Clean Air Authority potential Title V
Permit. Modeling indicated 609 lbs. of pollutants
potentially discharged into the air. This is below the
permitting threshold of 25 tons/year of air
contaminants.
N
N
N
Low
Moderate
Low
Air Emissions
Air Toxics
Air Contaminants
Visual Appearance
Maintenance of good neighbor policy has high
priority. No specific regulatory requirements apply;
subject to local standards. Defacto neighborhood
standards may dictate acceptable architectural
appearance.
N
High
Noise Control
Maintenance of good neighbor policy has high
priority. City of Yakima regulatory requirements
apply.
N
High
Endangered Species Act -
Legislation relating to salmon recovery in
Washington has the potential to significantly impact
wastewater discharges, water conservation, and
management of instream flows.
N
Moderate
Salmon
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 2-3
Table 2-1
Summary of Regulatory and Permitting Issues
Regulatory
Issue/Parameter
Issues and Current Status
NPDES
Permit
Limits'
Importance
to Planning
Endangered Species Act -
Other ESA listings in Yakima County are identified in
the text.
N
Low
Other
Pretreatment
DOE has approved the City's application for full
pretreatment authority and the permit formally
authorizes the City to implement its local pretreatment
program.
Y
High
Septage Acceptance
Landfill facility compliance issues with 503 and 308
regulations prohibiting acceptance of industrial
septage. WWTP looked to as possible disposal
option.
N
Moderate
Groundwater Protection
Continue to extend sewer service and limit
construction of new septic systems. Development
pressure driving use of on-site systems within the
Urban Growth Area,
N
High
Stormwater
EPA Phase 11 Stormwater Permitting regulation
became final on November I, 1999. The City of
Yakima is in the process of implementing a regional
stormwater program. Coordination is ongoing.
N
Moderate
I Content of renewed NPDES discharge permit, coded as follows:
Y, Yes included
N, No, not included
C, Concentration Limit
S, Supplementary Condition
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-4
2.2 Surface Water Quality Standards
The Yakima River flows east and south from Lake Keechelus through the Kittitas Valley,
then cuts a deep canyon through the Manastash and Umtanum Ridges to enter the middle
valley through a gap in Selah Ridge. Flowing through the City of Yakima, it leaves the
middle valley through Union Gap in the Ahtanun Ridge. The Yakima River then travels
80 miles through the lower valley and joins the Columbia River. The river has been
designated as a Class A receiving water in the vicinity of the wastewater treatment plant
outfall. The river currently supports many beneficial uses. Concerns have arisen about
maintaining river quality and protecting beneficial uses due mainly to agricultural and
historical mining impacts. Basin -wide problems include sediments, nutrients, pesticides,
turbidity, metals, bacterial contamination, and temperature.
As the river flows from Selah Gap to Union Gap, land uses in the Yakima Metropolitan
area which may impact changes to the river include urban and agricultural runoff,
industry, wastewater treatment facilities, and sand and gravel operations.
Regulatory beneficial uses of the Yakima River are outlined in Washington's Water
Quality Standards for Surface Waters of the State of Washington (WAC 173-201A) and
include the following: water supply (domestic, industrial, agricultural); stock watering;
fish migration; fish, crustacean and shellfish rearing; wildlife habitat; primary contact
recreation; sport fishing; boating and aesthetic enjoyment; commerce; and navigation.
Water quality of a Class A river must meet or exceed the requirements for all, or
substantially all, uses.
Section 303(d) of the federal Clean Water Act requires Washington State periodically to
prepare a list of all surface waters in the state for which beneficial uses of the water are
impaired by pollutants. The 303(d) designation establishes water bodies within the state
which have been determined by WDOE to contain one or more pollution parameters
which exceed water quality standards. The state is required to update the 303(d) list
every two years and submit the list to EPA, although no update was required in 2000.
Segment WA -37-1040 of the Yakima River, which receives the plant discharge, was
placed on WDOE's 1998 303(d) list for ammonia, chlorine, fecal coliform bacteria,
mercury, and silver. The ammonia and chlorine listings are associated with the Zillah
WWTP so do not directly affect the Yakima Regional WWTP. Additionally, the mercury
and silver listings are believed to be based on analytical errors and a WDOE study'
recommended removing these parameters from the 303(d) list in the next update. The
WDOE has determined that no significant receiving water problems will result from the
treatment plant discharge if the effluent limits contained in the NPDES discharge permit
are met. The WDOE has proposed a 2002-2004 303(d) list update that includes
temperature as a parameter of concern in the Naches River upstream and in downstream
segments of the Yakima River, though not in the segment receiving discharge from the
Yakima Regional WWTP.
Johnson, A. 2000. Concentrations of 303(d) Listed Metals in the Upper Yakima River. WDOE
Publication No. 00-03-024, Olympia, WA
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-5
2.2.1 Revised Surface Water Quality Standards
On July 1, 2003, Washington DOE amended WAC 173-201A. This adoption revises the
surface water quality standards by the following actions:
• Moving from the current class -based system to a use -based system for designating
beneficial uses of waters (for example swimming and aquatic life habitat).
• Making changes to the criteria (for example temperature and bacteria) established
to protect designated uses.
• Providing more clarity and detail on implementing the regulation, including the
state's antidegradation policy.
• Organizing the structure and sections of the regulation to make it easier to use.
The new rules were effective as of August 1, 2003. The new and amended water quality
standards serve as the basis for water quality modeling and establishment of projected
effluent limitations. However, the new numerical criteria are equivalent to the old for all
water quality parameters affecting major WWTP operations, so the changes are not
significant for the City of Yakima. The following is a summary of the revisions:
• The old standards had the Yakima River from the mouth to Cle Elum classified A
(excellent). Under the new water quality standards, the same reach is designated
for non-core salmon and trout spawning and rearing, primary contact recreation,
and a variety of water supply and miscellaneous uses.
• The special 21 °C temperature criteria in the old standards is still present in the
new standards for the Yakima River.
• The criteria for conventional water quality parameters are unchanged, including
the dissolved oxygen criterion of 8 mg/L.
• There are no changes to the metals criteria.
• The chronic ammonia criterion has been relaxed, but only for non -salmonid
waters; thus there is not change relevant to Yakima.
• Although DOE and EPA have stated intent to develop nutrient criteria for rivers,
this was not included in these revisions. There are no nutrient criteria in the new
standards.
• The mixing zone requirements in the new standards are identical to the previous
standards.
• The standards have been clarified as to procedures to modify site specific
standards, including water effects ratios for metals and use attainability analyses
for designated uses. These may be important tools to achieve compliance with
metals and nutrient criteria in the future.
• The anti -degradation clause in the standards has been strengthened to provide
more specific guidance. More documentation will be required in the future if
mass limits in NPDES permits are increased as a result of facility expansion.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-6
2.2.2 Antidegradation
The State's Antidegradation Policy requires that discharges into the receiving water shall
not further degrade the existing water quality of the water body. In cases where the
natural conditions of a receiving water are of lower quality than the criteria assigned, and
only when there are present obvious beneficial uses for the ambient receiving water or
when the natural conditions of the receiving water are of higher quality than the criteria
assigned, the natural conditions shall constitute the water quality criteria. More
information on the State's Antidegradation Policy can be obtained by referring to WAC
173-201A-070.
2.2.3 Criteria
The general surface water quality criteria for Washington specifies that surface water
standards must be consistent with the public health and public enjoyment thereof, and the
propagation of fish, shellfish, and wildlife.
"Numerical' water quality criteria are numerical values set forth in the Water Quality
Standards for Surface Waters of the State of Washington (WAC 173-201A). They
specify the levels of pollutants allowed in a receiving water while remaining protective of
aquatic life. "Numerical" criteria set forth in the Water Quality Standards are used along
with chemical and physical data for the wastewater and receiving water to derive the
effluent limits in the discharge permit. When surface water quality -based limits are more
stringent, or potentially more stringent, than technology-based limitations, they must be
used in a permit.
The State has issued ninety-one (91) "numerical" water quality criteria for the protection
of human health as adopted from the EPA under the National Toxics Rule. These criteria
are designed to protect humans from cancer and other disease, and are primarily
applicable to fish and shellfish consumption and drinking water consumption from
surface waters.
In addition to "numerical" criteria, "narrative" water quality criteria (WAC 173-201A-
030) limit toxic, radioactive, or deleterious material concentrations below those which
have the potential to: (a) adversely affect characteristic water uses; (b) cause acute or
chronic toxicity to biota; (c) impair aesthetic values; or (d) adversely affect human health.
"Narrative" criteria protect the specific beneficial uses of all fresh (WAC 173-201A-130)
and marine (WAC 173-201A-140) waters in the State of Washington.
The regulation of toxic metals by EPA and the states has been problematic. Much of the
problem hinges on EPA having established the toxics criteria based upon limited
laboratory research. EPA now recognizes that metals toxicity is significantly affected by
site-specific factors and that these site-specific factors should be considered in the
establishment of metals limits. Factors that should be considered include: toxicity
specific to effluent chemistry; toxicity specific to ambient water chemistry; different
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-7
patterns of toxicity for different metals; and the fate and transport of metals in the
receiving water. There are also concerns by EPA and other agencies that much of the
analytical data collected for assessing metals toxicity is invalid due to possible sampling
and analytical contamination. Clean and ultra clean sampling and analytical protocols are
now being developed to reduce the risk of contamination and to improve the accuracy of
the laboratory analyses for detecting low level concentrations of metals. The impact of
new sampling techniques on measured metals concentrations in the Yakima River is
currently being investigated by the Yakima Regional WWTP staff.
2.3 NPDES Permit
The Federal Clean Water Act (CWA, 1972, and amendments) established water quality
goals for surface waters of the United States. One of the mechanisms for achieving the
goals of the Clean Water Act is the NPDES permit program, which is administered by the
USEPA. The USEPA has delegated responsibility to administer the NPDES permit
program to the State of Washington (State) on the basis of Chapter 90.48 RCW which
defines WDOE's authority and obligations in administering the wastewater discharge
permit program.
The City of Yakima Regional WWTP currently operates under NPDES Permit No. WA -
002402 -3 issued by the WDOE. The permit was issued April 30, 2003, and is effective
June 1, 2003 through May 31, 2008. The permit includes Special Conditions and General
Conditions. Special Condition sections are as follows:
S1 — Discharge Limitations
S2 — Monitoring Requirements
S3 — Reporting and Recordkeeping Requirements
S4 — Facility Loading
S5 — Operation and Maintenance
S6 — Pretreatment
S7 — Residual Solids
S8 — Acute Toxicity
S9 — Chronic Toxicity
S10 — Receiving Water and Effluent Study
S 11 — Facility Plan
S 12 — Outfall Evaluation
S13 — Schedule of Compliance
In section Si — Discharge Limitations, the permit includes interim discharge limitations
that are effective through January 15, 2008, and final effluent limitations that are effective
January 16, 2008 through May 31, 2008. The final effluent limitations reduce allowable
maximum monthly and daily concentrations of copper and zinc from the interim limits.
All other interim Iimits remain the same. Table 2-2 summarizes the current NPDES
effluent limitations. The Yakima Regional WWTP has been in compliance with
respective limits for the last two years except for the following: July 2002 single day
ammonia violation due to power outage, November 2003 copper and single day pH
violation, and December 2003 pH violations on two days.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-8
Table 2-2
Current NPDES Effluent Limitations1
Parameter
Average Monthly2
Average Weekly
5 -day Biochemical Oxygen
Demand (BOD5)
30 mg/L
85% Removal
45 mg/L
Total Suspended Solids (TSS)
30 mg/L
85% Removal
45 mg/L
Fecal Coliform Bacteria
200 colonies/100 mL
400 colonies/100 mL
pH3
Between 6.0 and 9.0 at all times
Parameter
Average Monthly
Maximum Daily
Total Residual Chlorine (TRC)
0.012 mg/L
0.029 mg/L
Total Ammonia, as N
4.16 mg/L
12.3 mg/L
Total Coppers
9.84 (6.71) p.g/L
14.36 (9.80) µg/L
Total Lead
3.96 pg/L
5.77 pg/L
Total Silver
2.18 µg/L
3.17 µg/L
Total Zinc5
70.35 (45.70) p.g/L
95.82 (66.70) pg/L
Chronic WET Limit
No statistically significant difference in test organism
response between the chronic critical effluent
concentration (CCEC), 15.1% of the effluent, and the
control.
1 Average monthly and weekly effluent limitations are based on the arithmetic mean of the samples taken
except for fecal coliform, which is based on the geometric mean.
2 Average monthly effluent concentrations shall not exceed 30 mg/L or 15% of the respective monthly
average influent concentrations.
3 Indicates the range of permitted values.
4 Defined as highest allowable daily discharge, as the average measurement of the pollutant over the
calendar day.
s Values in parentheses are final limitations effective January 16, 2008 through
May 31, 2008. All other values are interim and final limits.
The mixing zone is defined in the permit as follows:
"The length of the chronic and acute mixing zones shall extend downstream no greater
than 310 feet and 31 feet, respectively. The width of the chronic and acute mixing zones
shall be no more than 50 feet wide. The aquatic life -based dilution factors for the chronic
and acute mixing zones were determined to be 6.61 and 1.51, respectively."
Section S4 - Facility Loading of the permit requires facility loading design criteria to be
determined through development of an approved Facility Plan. Criteria to be developed
(and subsequently not exceeded) include the following:
• Average flow (max month)
• BOD5 loading (max month)
• TSS loading (max month)
• Design population
As part of the Facility Plan, an assessment of the flow and wasteload compliance must be
submitted. The assessment must include comparison between existing and design
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-9
monthly average dry weather and wet weather flows, peak flows, BOD and TSS loadings;
and the percentage increase in these parameters since the last assessment. The report
must also state the present and design population or population equivalent, projected
population growth rate, and the estimated date that design capacity is projected to be
reached, according to the most restrictive parameter.
Section S10 — Receiving Water and Effluent Study requires collection of receiving water
information necessary to determine if the effluent has a reasonable potential to cause a
violation of the water quality standards. If reasonable potential exists, DOE will use the
information to calculate effluent limits. The effluent and receiving water must be
measured for hardness and ten metals. A Quality Assurance Project Plan was submitted
as required (provided in Appendix B), and the study must be submitted by May 31, 2007.
Section S 11 — Facility Plan requires submission of an approvable Facility Plan by
January 1, 2004. In a request and response both dated December 19, 2003 (both included
as Appendix C), WDOE allowed the City to submit the Final Facility Plan by March 1,
2004. The Facility Plan must be prepared in accordance with WAC 173-240, and must
address the following issues:
1. Comprehensive water quality evaluation.
2. Treatment plant configuration, including treatment of Del Monte flows.
3. Basis for capacity determination.
4. Basis for design of required upgrades.
5. Impacts of treating Del Monte flows, rather than spray field application.
6. Impact of the intermediate clarifier.
7. Documentation for SEPA and SERP determinations. (when completed, to be
incorporated as Appendix D)
8. Feasibility of using reclaimed water.
Section S12 requires that an Outfall Evaluation be conducted and report submitted by
January 15, 2005. Section S13 requires compliance with State Surface Water Quality
Standards for Copper, Lead, Silver, and Zinc by January 16, 2008. To accomplish this, a
--Z.Metals Study must be accomplished, with a scope of work report due January 1, 2004
m-, (deadline extended with Facility Plan to March 1, 2004) and the Study due July 15, 2006.
A copy he scope of work report is included as Appendix E.
IL 1 r
2.3.1 Development of Mixing Zone -Based NPDES Permit Limits
a
, -, DOE's NPDES Permit Writer's Manual (Pub. #92-109) and EPA's Technical Support
``=
_ Document for Water Quality -based Toxics Control (Pub #EPA/505/2-90-001) were
s� V
£ .; followed to establish proposed effluent limits for current conditions. The results were
<9 4, submitted in September 2003 to WDOE in a "City of Yakima WWTP Mixing Zone
�.1 Study" prepared by Cosmopolitan Engineering Group to aid in developing final effluent
slimits for the current NPDES permit. A copy is included as Appendix F. Several
methods were used to develop alternatives for the limits, including standard steady state
S * o (the basis of the current NPDES limits), seasonal steady state, dynamic modeling, and use
-, V
tet ---,:,/,
of a variance clause in the standards for the mixing zone definition. Dilution factors and
f
� J
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-10
effluent limits were developed for each option, and recommended limits are included in
the study for WDOE consideration.
The water quality -based effluent limits developed from this effort include ammonia,
chlorine, copper, lead, silver, and zinc. The acute critical effluent concentration (ACEC)
and chronic critical effluent concentration (CCEC) were also determined from this
modeling. The ACEC and CCEC are the maximum concentrations of effluent during
critical conditions at: the boundary of the zone of acute criteria exceedance (ACEC), and
the boundary of the mixing zone (CCEC) as assigned in the permit.
Although the US Bureau of Reclamation has made significant changes in the operation of
the upstream reservoir system, which affects the river flow, there is no known
information that suggests further operational changes. Therefore, the future dilution and
effluent limit projections were based solely on projected changes in the effluent flow rate.
Mixing zone modeling will need to be repeated for each 5 -year NPDES permit cycle to
assess actual limits versus projections.
2.3.2 Development of Watershed -Based Effluent Limits
The Lower Yakima River may be subjected to future total maximum daily load (TMDL)
limits for dissolved oxygen, nutrients, and temperature. The effluent constituents that
may be affected include CBOD5, ammonia, total nitrogen and orthophosphate. The
development of TMDLs for these parameters would incorporate all anthropogenic
discharges to the river, and is beyond the scope of the Facility Plan. However, the
Facility Plan describes the current watershed water quality conditions, potential future
actions, and recommendations to respond to future TMDLs when and if they are
developed. Recommendations include potential data collection activities and treatment
improvements to handle future nutrient limits and/or more stringent CBOD limits.
2.3.3 Water Quality Criteria for Conventional Parameters
The water quality criteria for conventional water quality parameters affected by WWTP
effluent are summarized in Table 2-3.
Table 2-3
Conventional Water Quality Criteria for the Yakima River
Conventional
Parameters
Criteria
Dissolved Oxygen
Shall exceed 8.0 mg/L
Temperature
Shall not exceed 21 °C. No human increase above
34/ (T+9)
Fecal Coliform
Geo. mean —100 colonies/100 mL
90"' percentile — 200 colonies/100 mL
pH
6.5 to 8.5
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 2-11
2.3.4 Water Quality Criteria for Toxicants
Toxic substances typically present in municipal wastewater effluent include ammonia,
chlorine, and metals. WDOE's recently renewed NPDES permit for the City of Yakima
WWTP established the following metals as having a reasonable potential to exceed water
quality standards: copper, lead, silver and zinc.
The criteria for ammonia are dependent upon the receiving water pH and temperature,
and the metals criteria are dependent upon hardness at the mixing zone boundaries.
WDOE's default methods of assessing compliance with water quality standards specifies
that the toxicant criteria be based on critical 10th or 90th percentile values for temperature,
pH and hardness. The criteria for toxic substances of concern based on these
conservative ambient values are listed in Table 2-4.
Table 2-4
Toxicant Water Quality Criteria In -Stream for the Yakima River
Toxic Parameters
Acute Criteria
(µg/L)
Chronic Criteria
(µg/L)
Ammonia -N
17,800
1,480
Chlorine
19
11
Copper
5.38
3.28
Lead
16.7
0.50
Silver
0.42
—
Zinc
40.6
30.6
2.3.5 Mixing Zone Regulations
Mixing Zone Definition. The water quality standards allow the use of mixing zones, with
conditions, for NPDES permitted discharges. A mixing zone is a volume of a receiving
water where mixing results in the dilution of the effluent with the receiving water. If a
mixing zone is allowed by DOE, compliance with the water quality standards is required
at the boundary of the mixing zone (WAC 173-201A-400(5)).
Mixing Zone Criteria (Chronic Mixing Zone). WAC 173 -201A -400(7)(a) specifies the
maximum size of a mixing zone. For a discharge into a river, the mixing zone where
conventional parameters and chronic toxicity criteria apply shall comply with the most
restrictive combination of the following:
• Not extend in a downstream direction for a distance from the discharge port(s)
greater that 300 feet plus the depth of water over the discharge port(s),
• Not utilize greater than 25 percent of the flow, and
• Not occupy greater than 25 percent of the width of the water body.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-12
Acute Mixing Zone Criteria. WAC 173-201A-100(8) allows conditional acute criteria
exceedence. Similar to application of chronic criteria, a zone where acute criteria may be
exceeded must comply with the most restrictive combination of the following:
• Not extend beyond 10 percent of the distance towards the upstream and
downstream boundaries of an authorized chronic mixing zone, as measured
independently from the discharge port(s),
• Not utilize greater than 2.5 percent of the flow, and
• Not occupy greater than 25 percent of the width of the water body.
Existing Mixing Zone Dimensions. The City of Yakima's NPDES permit specifies acute
and chronic mixing zone boundaries of 31 and 310 feet, respectively, downstream of the
diffuser. The acute and chronic dilution factors specified in the permit are 1.51 and 6.61,
respectively.
Mixing Zone Variance Provisions. The water quality standards allow DOE to consider
exceedences of the mixing zone numeric size criteria described above, with the following
stipulations:
• The discharge existed prior to November 24, 1992,
• Altering the size configuration is expected to result in greater protection to
existing and characteristic uses,
• The discharge provides a greater benefit to the existing or characteristic uses of
the water body due to flow augmentation than the benefit of removing the
discharge if removal of the discharge is the remaining feasible option, or
• The exceedence is necessary to accommodate important economic or social
development in the area.
The Yakima WWTP discharge satisfies these criteria on the basis of part (i) alone, having
existed long before 1992. Before approval of an exceedence of the mixing zone size
criteria, DOE must be satisfied that:
• The discharge receives treatment consistent with all known available and
reasonable technology (AKART),
• The discharger utilizes all economically achievable siting, technology, and
managerial options that result in full or significantly close compliance, and
• The supporting information clearly indicates the mixing zone would not have a
reasonable potential to cause a loss of sensitive or important habitat, substantially
interfere with the existing or characteristic uses of the water body, result in
damage to the ecosystem, or adversely affect public health.
The Yakima WWTP clearly meets AKART provisions. Sub -parts ii and iii would require
subjective determinations by DOE in order to qualify for an exemption.
If DOE grants an exemption to the size criteria, the exemption shall be reexamined during
each renewal of the NPDES permit. In the Mixing Zone Study, one of the alternatives
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-13
includes assessment of dilution under these variance provisions. The City would be
seeking a variance only for the chronic and acute criteria that are based on percentage of
ambient flow. The physical mixing zone dimensions of 31 feet (acute) and 310 feet
(chronic) would not be altered.
2.3.6 Critical Effluent Flows
DOE's Permit Writer's Manual specifies that steady-state mixing zone analyses for
NPDES permits be conducted at the highest actual monthly average during the past 3
years for conventional parameters and chronic toxicants. The highest actual daily flow
must be used for acute toxicants. These statistics were determined by DOE from DMRs
submitted by the City of Yakima, and are cited in the NPDES Permit Fact Sheet. The
critical flows specified by DOE protocol are listed in Table2-5. The seasonal differences
in effluent flow peaks are nominal, so the annual values are also used in seasonal
modeling.
Table 2-5
Critical Steady -State Effluent Flow Rates for Mixing Zone Study
Flow Condition
Model Application
Flow Rate
Maximum Month
Chronic
18.3 mgd
Maximum Day
Acute
20.0 mgd
2.3.7 Recommended Water Quality -Based Effluent Limits for the Current
NPDES Permit
The recommended effluent limits for the current NPDES permit are those based on the
continuous simulation dynamic modeling. This wasteload allocation method is fully
supported by WDOE and EPA protocol, and provides a more accurate determination of
limits designed to meet water quality criteria in the receiving water.
The ACEC and CCEC should be based on annual dilution factors calculated from the
continuous simulation model. Likewise, metals concentrations do not exhibit seasonal
trends, thus the recommended limits are based on the annual model. However, ammonia
concentrations are seasonal, as is the treatment plant's ability to remove ammonia.
Therefore, the ammonia limits should vary seasonally based on the continuous simulation
model results. Recommended effluent limitations for the current NPDES permit are
provided in Table 2-6.
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PAGE 02
Table 2-6
Recommended Effluent Limits for the Current NPDES Permit
Parameter
Average Monthly Limit
Maximum Daily Limit
Amtnonia as N
October — February
March - September
8.3 rag/L
7.5 mg/L
28 mg/L
25 mg/L
Copper
10.71tg/L
15,6 lig/1,
Lead
13.7 µg/L
19.9 µg/L
Silver
3.4 itgfL
5.0 µg/L
Zinc
73 µg/L
107 µg/L
Note: ACEC — 45%, CCEC = 7.2%
2.3.8 Projected Water Quality -Based Effluattt Limitations at Buildout
There are numerous variable factors that will determine water quality -based effluent
limitations for ammonia and metals in the future, including the growth in effluent flow
rates, potential changes in low -flow management of the watershed by US Bureau of
Reclamation, and long -terns changes in ambient water quality in the Yakima River system
upstream of the WWTP, In the absence of any knowledge regarding future changes in
ambient conditions or control strategies, effluent limit projections for buildout conditions
are based on future effluent flow projections.
Effluent flow projections were developed by HDR in the October 2000 Draft Wastewater
Facilities Plan. That report established a baseline annual average flow of 11.28 mgd for
1999. The annual average flow at buildout was projected to be 22.37 mgd, which is
approximately double the 1999 projection. Since the recommended effluent limits for the
current NPDES permit are based in -part on 1999 effluent flows, this ratio of future -to -
current flows were used to project effluent limits for ammonia and metals at buildout.
The projected buildout effluent limits are presented in Table 2-7.
Table 2.7
Projected Buildout Effluent Limits
Parameter Average Monthly Limit Maximum Daily Liwwit
Ammonia as N 5.8 mg/L 20 mg/L
Copper 8.0 µg/L 11.6 Iig/L
Lead 7.6 µg/L 11.1 µg/L
Silver 2.6 µg/L 3.7 µg&
Zinc 55 µgm 80 µg/L
Note: ACEC = 62%, CCEC = 13.4%
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2.4 Future Basin -Wide Water Quality Issues
There are various water quality concerns in the Yakima River associated with cumulative
point and nonpoint discharges in the watershed. As these basin -wide water quality
concerns are identified, DOE is charged with allocating equitable wasteload limits for all
sources to bring the river into compliance with the standards. The field investigations
and modeling studies for many of the water quality parameters of concern are not
completed at this time, therefore, projection of specific potential effluent limits for the
treatment plant that may result from the basin -wide. water quality controls is not possible.
However, this section describes the current water quality parameters of concern for the
Yakima basin, and establishes facility planning guidelines so that future wastewater
facility improvements will be capable of adapting to additional effluent limits. The
principal effluent constituents that fall into this category of potentially greater restrictions
are temperature, CBOD5 and phosphonis.
Section 303(d) of the federal Clean Water Act requires states to create a list of surface
waters that are not meeting water quality standards. The current 303(d) list was adopted
in 1998. The Yakima WWTP discharges to Segment ID No. WA -37-1040 of the Yakima
River, which extends from the Sunnyside Dam Bridge at mile 103.8 to the Naches River
at mile 116.3. The lower portion of this segment is under the jurisdiction of the Yakarna
Indian Nation.
Yakima River segment No. WA -37-1040 was placed on the 1998 303(d) list for
ammonia, chlorine, fecal coliform, mercury, and silver. As discussed in Section 2.2, the' •
ammonia and chlorine listings are associated with the Zillah WWTP discharge; and do
not affect the Yakima WWTP and it is expected that the mercury and silver listings will
be removed from the 303(d) list in the next update. The proposed 2002-2004 303(d) list
includes temperature as a parameter of concern.
The lower Yakima River was included on the 1996 303(d) list for sediment and sediment -
borne pollutants like DDE and DDT attributed to irrigation returns. A suspended
sediment and DDT total maximum daily load (TMDL) study was completed by WDOE
as required under the Clean Water Act. The TMDL established sediment reduction goals
and irrigation return policies that are expected to produce compliance with the DDT
human health criteria in fish and water by 2017. None of the requirements in the TMDL
include limitations relevant to the City of Yakima WWTP.
2.4.1 Temperature
Both the previous and recently updated state water quality standards include a special
condition for temperature in the Yakima River, consisting of a revision of the standard to
21°C. Based on this criterion, the segment of the Yakima River that the City of Yakima
discharges to has not been placed on the 303(d) list. However, the river segment just
below Union Gap is listed for temperature as well as many of the tributaries into the
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YAKIMA WWTP PAGE 04
Yakima such as the Naches River and its tributaries, A temperature TMDL is scheduled
to be started on the Naches River by WDOE in 2004.
The impact of the Yakima WWTP discharge on the receiving water was modeled by a
simple mass balance mixing analysis using the revised chronic dilution factor of 13.8, An
effluent temperature of 24°C and ambient temperature of 19.9°C have been assumed for
the calculation of temperature impacts, The temperature water quality standard will be
met, as shown in Table 2-8. The maximum temperature at the mixing zone boundary will
be 20,2°C at 90th percentile ambient conditions, which is ander the 21 °C criteria. The
maximum temperature increase above ambient will be 0,3°C, which is less than the
maximum increase of 1.5°C allowed in the water quality standards.
Table 2-8
Analysis of Temperature Impact
Parameter
Value
Eluent Temperature (°C)
T ^^^ 24.0
Ambient Temperature (°C)
19.9
Dilution Factor
13.8
Final Temperature (°C)
20.2
Water Quality Standard (°C)
21.0 (max)
Temperature Increase (°C)
0.3
Water Quality Standard (°C)
1.5 (max increase)
WDOE also evaluated the temperature impact of the Yakima WWTP discharge in the
NPDES permit fact sheet, and also concluded that the temperature criteria will be met.
Therefore, no temperature limitations are anticipated to be required now, although it is
unclear what will occur in the future as a result of a temperature TMDL. Nevertheless,
wastewater facility improvements should be designed to not significantly increase the
temperature of the effluent over existing conditions, in order to assist with potential
future compliance needs,
2.4.2 Biochemical Oxygen Demand
The standard for dissolved oxygen is met in river segment WA -37-1040, thus is not
included on the 303(d) list. However, river segments downstream from the Yakima
WWTP (WA -37-1010) are on the 303(d) list for oxygen, Therefore, WDOE is obligated
to perform a TMDL for the. lower Yakima River to achieve compliance with the dissolved
oxygen standard. The TMDL may include allocations for C13OD, ammonia and
phosphorus. Because of the delayed -effect nature of dissolved oxygen dynamics, the
TMDL, will likely need to extend to upstream segments in order to meet downstream
criteria. WDOE has stated their intent to develop a comprehensive dissolved oxygen and
nutrient model for the lower Yakima River that would extend at least to the confluence of
the Yakima and Naches Rivers, and thus would include the Yakima WWTP discharge.
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YAKIMA WWTP PAGE 05
The impact of the City's discharge on dissolved oxygen was modeled by WDOE with a
very conservative model named DOSAG, which is a simple spreadsheet version of the
modified Streeter -Phelps equation. The results of the model are presented in the Fact
Sheet for the NPDES permit, and suggest that there is a potential for the Yakima WWTP
discharge to exceed the dissolved oxygen criteria downstream. WDOE uses the DOSAG
model as a screening tool to assess whether additional analysis is necessary. WDOE has
concluded that additional analysis is necessary for the Yakima WWTP since (1) there are
multiple sources of oxygen demanding wastes in the Yakima watershed, (2) the effects of
dams and other hydraulic strictures on dissolved oxygen are beyond DOSAO's
capabilities, and (3) a TMDL is required for dissolved oxygen in the lower Yakima River.
WDOE will conduct a TMDL for dissolved oxygen in the Yakima River at some future
date that will consider cumulative loadings of BOD and nutrients. As stated in the
current NPDES peernit, allowable CBOD loadings for all sources will be determined after
a comprehensive TMDL model is developed. Therefore, it is not feasible to predict
future CBOD limits for the Yakima WWTP until the TMDL is completed, which is likely
to be approximately five years.
Interium effluent limits will be the same technology-based limits in the current permit.
Final CBOD limits will be established through a revision to the NPDES permit when the
TMDL is completed. Therefore, wastewater facility modifications occurring in this
interim period should be planned with allowances for future upgrades that would reduce.
CBOD loadings below the current technology-based limits, if that should result from a
future TMDL.
2.4.3 Phosphorus
Discharges of nitrogen and phosphorus may stimulate algal growth in the form, of
periphyton attached to the river substrate, or suspended algae in reservoirs. Excessive
periphyton or phytoplankton growth may adversely impact pH, dissolved oxygen,
fisheries habitat and visual aesthetics. WDOE has determined that nitrogen is readily
available in Washington rivers and streams. Therefore, control of nuisance algal growth
is typically accomplished by limiting phosphorus discharges from anthropogenic sources,
including wastewater treatment plants. For example, phosphorus controls have been
placed on dischargers in the Spokane River for many years to control periphyton, pH, and
dissolved oxygen,
The Yakima River is not currently included on the 303(d) list for phosphorus or any other
parameters related to excessive periphyton growth. There are no phosphorus limitations
on any point or rnonpoint discharges to the river, and' no known phosphorus Management
plans have been developed in the watershed. Therefore, the current NPDES permit does
not include phosphorus limitations.
However, WDOE has identified phosphorus as a parameter of concern and will include it
in the anticipated dissolved oxygen TMDL for the Yakima River, Additionally, EPA is
developing nationwide nutrient 'criteria for rivers, and WDOE is planning for eventual
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-18
adoption of such criteria in Washington. Point and nonpoint discharge criteria for
phosphorus are anticipated in the future. Wastewater discharges to streams may be
required to remove phosphorus through treatment. Wastewater facility modifications
occurring in this interim period should be planned with allowances for future upgrades
that would reduce phosphorus loadings.
2.5 Reliability Classification
The WDOE has adopted USEPA's reliability classifications for sewerage works within
their Criteria for Sewage Works Design (December 1 998). The reliability standards
establish minimum levels of reliability for three classes of wastewater treatment plants.
The classification of a particular facility is based on the water quality and public health
consequences of a component or system failure. Class I facilities discharge near drinking
water intakes, into shellfish waters, near areas used for water contact sports, or in dense
residential areas, and may permanently or unacceptably damage the receiving waters or
public health. Class II facilities discharge at a moderate distance from the sensitive areas
listed and would not permanently or unacceptably damage public health or the receiving
waters during short periods of operational interruption. Class III facilities are works that
are not otherwise designated as I or II. The City of Yakima's WWTP is designated as
Reliability Class II.
The DOE criteria require that capabilities be provided for satisfactory operation during
power failures, flooding, peak loads, equipment failure, or maintenance shutdown. In
general, unit operations must be designed so that hydraulic capacity is maintained with
the largest flow -capacity unit out of service. For mechanical systems a backup unit is
typically required. The difference between Class I and Class II requirements are that
primary and final sedimentation basins and trickling filters for Class II should be
sufficient in number and size so that, with the largest unit out of service, the remaining
units have capacity of at least 50 percent of the design flow, whereas Class I requires at
least 75 percent capacity for final sedimentation basins and trickling filters with the
largest unit out of service.
The criteria also require that two separate and independent sources of electric power be
provided from either two separate utility substations, or from a single substation and a
generator located at the plant. For Class I, the backup power must be sufficient to operate
all vital components and critical lighting and ventilation during peak wastewater flow
conditions. The requirements for Class II are the same as Class I, except that vital
components used to support the secondary processes do not need to operate for full
treatment, but only to maintain the biota.
2.6 Biomonitoring and Whole Effluent Toxicity Testing
Biomonitoring and Whole Effluent Toxicity (WET) testing are methods of examining the
impact of discharge from wastewater treatment facilities on water quality. Biomonitoring
is the use of a biological entity as a detector and its response as a measure to determine
environmental conditions. As the regulatory approach shifts from technology based
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 2-19
permitting to water quality based permitting, biomonitoring and whole effluent toxicity
tests are likely to increase in importance in the permitting and operation of wastewater
treatment facilities. These biological tools can be used to develop specific chemical
criteria for pollutants not addressed directly in the Washington rules, or to demonstrate a
difference between the perceived toxicity of a chemical and the actual toxicity in a
specific receiving stream.
The Yakima Regional WWTP is currently required to follow a program of chronic and
acute WET tests. These tests are included in the NPDES permit requirements to
determine if the effluent affects the survival of certain test organisms. Bi -monthly acute
WET tests using EPA test protocol (EPA/600/4-90/027F, as amended) are performed in a
48-hour static test of Ceriodaphnia dubia. Bi -monthly chronic WET testing is also
performed using Ceriodaphnia dubia, and EPA test protocol (EPA/600/4-91/002, as
amended). The permit says "There shall be no significant acute toxicity in a test
concentration representing the acute critical effluent concentration (ACEC). The ACEC
means the maximum concentration of effluent during "critical" conditions at the
boundary of the acute mixing zone assigned pursuant to WAC 173-201A-100, and equals
sixty-six and two tenths percent (66.2%) final effluent." The permit contains similar
language for the chronic WET tests, "There shall be no significant chronic toxicity in a
test concentration representing the chronic critical effluent concentration (CCEC). The
CCEC means the maximum concentration of effluent during "critical" conditions at the
boundary of the chronic mixing zone assigned pursuant to WAC 173-201A-100, and
equals fifteen and one tenth percent (15.1%) final effluent." If a statistically significant
difference between the control and the test organisms indicates effluent toxicity, then the
pennittee is required to begin an additional series of monitoring. If this series shows
compliance, the permittee is allowed to return to the original schedule. If a violation of
the permit limits occurs, the permittee is required to submit an acute Toxicity Reduction
Evaluation (Ti/Re) plan based on WAC 173-205-100(2). The Ti/Re is subject to
approval by WDOE. The permittee is required to implement the applicable elements of
the Ti/Re immediately upon receipt of the approval letter. The evaluation attempts to
identify the source of toxicity and determine long-term solutions to eliminating the
toxicity in the wastewater discharge.
The Yakima Regional WWTP completed a Ti/Re in 1999 because the treated effluent had
exhibited some toxicity to Ceriodaphnia dubia on an intermittent basis. Ceriodaphnia
dubia is not found in the Yakima River but is a nationwide standard organism required
for conducting WET tests. The same tests performed on bullhead minnows did not
exhibit reaction to toxicants in the treated effluent. The Yakima Regional WWTP
however, was required to conduct the chronic and acute WET tests using the most
sensitive species.
The Ti/Re investigation initially gave confusing results. After investigation of the
business community, fruit packers were identified as a possible source of toxicity. In
reviewing permits issued by WDOE, the City pretreatment staff realized that certain fruit
packers were permitted to discharge highly toxic fungicide to the sewage collection
system under the WDOE issued State Waste Discharge Permit. After discussions with
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-20
the fruit packers and the voluntary elimination of the fungicide discharge, the Yakima
Regional WWTP has been able to achieve acceptable results with WET testing.
Additionally, as discussed in Section 2.3, and detailed in the Mixing Zone Study, the
ACEC and CCEC should be based on annual dilution factors calculated from the
continuous simulation model. These new concentrations will impact the WET testing by
reducing the percentage of final effluent used for the tests.
2.7 Infiltration and Inflow Control
Infiltration to the Yakima collection system has been a major concern, and several efforts
to reduce infiltration and inflow have been undertaken by the City in the past. Infiltration
has been a seasonal problem associated with the irrigation system in the community.
When the irrigation systems are filled during the growing season, significant increases in
flow are experienced at the treatment facility which is attributable to infiltration. Section
10, Analysis of Existing Wastewater Collection Facilities, includes a more detailed
analysis of infiltration and inflow issues.
2.8 Groundwater Protection and Impacts on Unsewered Areas
Classifications of groundwaters are designated according to the uses for which they are
presently suitable or intended to become suitable. These include agricultural, domestic,
industrial, and/or potable use. The WDOE considers all groundwater to be a source or
potential source of drinking water, and WAC 173-200 Water Quality Standards for
Ground Waters of the State of Washington requires any discharge to the subsurface
geology to meet drinking water standards prior to discharge. The following paragraphs
describe the regulations protecting groundwater, and the wastewater disposal practices
that are affected by these regulations. The disposal of biosolids from the wastewater
treatment facilities as it may affect groundwater is addressed separately in Section 9.
2.8.1 General Groundwater Quality and Protection
Groundwater underlying the City of Yakima is relatively isolated from surrounding
subsurface water by two uplifted ridges, one to the north and one to the south, which form
an underground bowl. The surface of the groundwater aquifer lies from a few feet to over
40 feet below the ground surface. Although thorough analysis of aquifer vulnerability has
not been determined for the Yakima River Basin, data is currently available to allow
groundwater mapping. At greatest risk are shallow aquifers located in areas of high
recharge potential and with urban or industrial land use, such as the Yakima Metropolitan
Area. There has been some degradation of the groundwater from spills and leakage of
underground storage tanks and from wastewater disposal through the use of septic tanks
and drainfields. Solvents such as perchlorethelyne are present in elevated levels in some
portions of the aquifer, as well as elevated nitrogen levels and bacteriological counts. As
a result, the use of the shallow aquifer in the Yakima area has been essentially
discontinued as a source of domestic water. The primary source of domestic water supply
for the City of Yakima is obtained from the Naches River. This supply is supplemented
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 2-21
by groundwater during emergencies from the deep aquifer which has excellent water
quality.
There are no specific local groundwater protection districts or regulations. The
groundwater has not been designated as a sole source aquifer under the Safe Drinking
Water Act. Yakima County regulates activities that may have adverse impacts on
groundwater such as land developments which do not connect to the area sewer system.
2.8.2 Regulation of Septage Disposal
The Yakima County Public Works Department operates a septage receiving and disposal
facility at the Cheyne landfill. The landfill has two lagoons which are provided to collect
and dry domestic septage. The cost of septage disposal at the landfill is approximately
$.033/gallon. As a result of the low costs of septage disposal, other alternative disposal
methods are seldom, if ever, used in the Yakima area.
The Yakima Regional WWTP provides an alternative for septage disposal. Septage is
accepted at the wastewater facility in accordance with the City's sewer use ordinances
and fees are assessed based on a schedule of charges developed for the handling and
treatment of septage at the WWTP.
In March of 1998, the State of Washington enacted revisions to WAC 173-308. Because
of these revisions there are now certain restrictions on the type of industrial septage that
may be accepted at the Cheyne landfill. Industrial septage is defined as any non-domestic
septage from a business. This restriction began on January 1, 2000. Representatives of
WDOE, Yakima County, Yakima Health District, and the City of Yakima met to discuss
the septage lagoons at the Cheyne landfill.
The restrictions at Cheyne landfill are:
• No industrial septage as of January 1, 2000. Septage from business that is only
domestic in nature will be accepted. If domestic septage is mixed with industrial
septage, the mixture is considered industrial septage. The County is making
determinations on specific businesses on a case by case basis when it is unclear
what classification the septage falls into.
• No new industrial customers. Even if the septage from a business qualifies as
domestic in nature, if they have not sent septage to Cheyne in the past, they will
not be allowed to do so now or in the future.
• No grease is accepted.
Yakima County will be required to find alternative means of disposal of septage from
industrial customers that are unable to utilize the Cheyne landfill. Septage customers are
generally located in unincorporated areas under the jurisdiction of Yakima County.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 2-22
In accordance with current policy, the Yakima Regional WWTP does not accept
industrial septage. Industrial septage disposal options at the present time include:
• Industrial septage that is not classified as dangerous waste under WAC 173-303
can be dried and sent to a sanitary landfill. The drawbacks to this option are a
lack of storage space while the septage dries and odors associated with the drying
septage.
• Industrial septage that is contaminated with petroleum products can be dried and
sent to a petroleum contaminated soil landfill. At least three of these types of
landfills are located in the Yakima Valley. In addition to the previous drawbacks,
there is an additional expense of paying to have the material treated.
• Industrial septage that is classified as dangerous waste must be sent to a dangerous
waste disposal facility such as Rabanco. Although the septage volume can be
reduced by drying the septage, this is still an expensive disposal method. There
are businesses in the valley that will containerize and ship this material.
• The Port of Sunnyside is accepting a limited amount of industrial septage.
Should the Yakima Regional WWTP be mandated with the responsibility for acceptance
of septage by WDOE, there are a number of legal and procedural issues associated with
accepting industrial septage. Each load of industrial septage disposed of at the WWTP
would need to be characterized before it is accepted, including an intensive chemical
analysis performed at least once to ensure that the septage was not toxic to the treatment
process or result in violation of the NPDES permit. Depending on the type of business
and the constituents found in the first test, future testing may be reduced.
Acceptance of the industrial septage at the Yakima Regional WWTP would result in an
increase in plant loading. If all of the industrial septage is the same strength as domestic
septage there would be an estimated 5-10 percent increase in plant loading. Future
upgrades and/or expansions of the WWTP would need to account for any mandatory
delegation of the treatment facility for acceptance of septage.
2.9 Biosolids Management
The management of residual solids produced by treatment of wastewater from the
Yakima Urban Area has been the subject of several previous investigations. This topic is
thoroughly discussed in Section 9 - Biosolids Management.
Biosolids are defined as "...municipal sewage sludge that is primarily organic semisolid
product resulting from the wastewater treatment process, that can be beneficially recycled
and meets all requirements under this chapter." (RCW 70.95J). There are several local,
state and federal regulations and guidance on biosolids management and disposal.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-23
2.9.1 Federal Regulations
Federal regulations regarding biosolids management are outlined in 40 CFR 503 -
Standards for the Use or Disposal of Sewage Sludge. Chapter 503 gives general
requirements, pollution limits, management practices, operating standards, and
monitoring and reporting requirements for land application of biosolids.
Pollution limits for land application are given for arsenic, cadmium, chromium, copper,
lead, mercury, molybdenum, nickel, selenium, and zinc. Ceiling concentrations are given
for biosolids sold or given away in bags or other containers, while cumulative pollutant
loading rates, pollutant concentrations, and annual pollutant loading rates apply to
biosolids applied to agricultural land, forest, a public contact site, or a reclamation site.
The annual application rate is also limited to the agronomic nitrogen requirement for the
crop or vegetation grown on the land application site. Finally, pathogen requirements and
vector attraction reduction requirements must be met prior to land application of
municipal biosolids.
2.9.2 Washington Regulatory Guidance
Biosolids regulations have been developed by many states as well. These regulations vary
considerably from state to state, must be at least as restrictive as the Federal requirements.
The objective in these states is to derive the maximum resource benefits of the biosolids
land application while protecting the environment and public health.
The disposal of biosolids produced in the treatment process varies from community to
community. Solids from Yakima undergo anaerobic digestion, dewatering, and transport
to a land application site for beneficial re -use. Regulations regarding general
requirements and management practices are contained in RCW 70.95 J: Municipal
Sewage Sludge — Biosolids. This law has the greatest impact on biosolids and their
beneficial re -use. The law required WDOE to implement a statewide biosolids
management plan. It also provides for public input into the permitting process, public
education, and delegation of permitting to local jurisdictional health districts with WDOE
reviewing the permits. Biosolids from the Yakima Regional WWTP must also be utilized
in accordance with the requirements of the Yakima Health District and WAC 173-304
(minimum functional standards for solids waste handling). Biosolids Management is
discussed in detail in Section 9, Biosolids Management.
2.10 Land Application of Treated Wastewater
When properly designed and operated, land application of treated WWTP effluent can be
advantageous because of the assimilative capacity of plants for remaining nutrients such
as nitrogen and phosphorus, the adsorption of heavy metals onto soils, the degradation or
volatilization of organic constituents, and reduction of temperature impacts to receiving
streams. Applying wastewater effluent to agricultural land utilizes the abilities of both
the crops and the soil to provide additional treatment and removal of organic pollutants
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-24
and inorganic nutrients, Concerns are periodically raised about how land application of
treated wastewater may result in degradation of groundwater.
In many communities, land application of treated municipal effluents has been considered
as an option to continued discharge to surface waters, especially as more stringent
wastewater discharge requirements are implemented, particularly for nutrients and
temperature. When wastewater discharges are removed as a source of instream flow,
water rights issues may arise.
Many states recognize the value of treated municipal wastewater as a nonpotable water
source. Reclaimed wastewater has been used to serve agricultural needs, as industrial
process water, and for nonpotable services in large business complexes. Switching from
potable to nonpotable water for industrial uses can be very expensive, due to the need for
retrofitting a community with dual piping for potable and nonpotable water. If the savings
in potable water is large enough, or if the system is part of a new construction project,
water reuse can meet both water conservation and pollution abatement needs.
2.10.1 National Perspective
Currently, there are no federal regulations directly governing water reuse practices in the
United States. Water reuse regulations have been developed by many states. These
regulations vary considerably from state to state. Some states, such as Arizona,
California, Florida, Oregon, Texas, and Washington have developed regulations that
strongly encourage reuse as a water resources conservation strategy. These states have
developed comprehensive regulations specifying water quality requirements and/or
treatment processes for the full spectrum of reuse applications. The objective in these
states is to derive the maximum resource benefits of the reclaimed water while protecting
the environment and public health.
2.10.2 Washington Regulatory Review
With the passage of Substitute Senate Bill 5605 in 1995, the Washington State legislature
reinforced its finding that by encouraging the use of reclaimed water, the state will
continue to use water in the best interests of present and future generations. In this
amendment to the "Reclaimed Water Act," reclaimed water is no longer considered
wastewater. New minimum requirements and allowances have been established for
surface percolation of reclaimed water and discharge of reclaimed water for streamflow
augmentation.
The amended "Reclaimed Water Act" further authorized and directed the WDOE and the
Washington Department of Health (WDOH) to develop standards, procedures, and
guidelines for discharge of reclaimed water to created and natural wetlands, and for direct
recharge (injection) of reclaimed water to ground water aquifers. The intent of the
legislation was to encourage and facilitate the use of reclaimed water to replace potable
water in nonpotable applications, and to supplement existing surface and ground water
supplies.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-25
The Washington Water Reclamation and Reuse Interim Standards protect public health
by requiring a specific level of water quality and treatment corresponding to each
beneficial use of reclaimed water. Four classes of reclaimed water are allowed, as
appropriate, for a variety of irrigation, commercial, industrial, and other beneficial uses.
Class A Reclaimed Water has the highest level of treatment and quality, requiring
oxidation (secondary treatment), coagulation, filtration, and disinfection, with a median
number of total coliform organisms not exceeding 2.2 per 100 ml. Reclaimed water
Classes B, C, and D require oxidation and disinfection, with median numbers of total
coliform organisms not exceeding 2.2, 23, and 240, respectively, per 100 mL Monitoring
requirements for reclaimed water are shown in Table 2-9.
Table 2-9
Washington State Monitoring Requirements for Reclaimed Water'
Parameter
Sample Type and
Frequency
Compliance Requirements
Biochemical
Oxygen Demand
24-hour composite,
collected at least
weekly
Shall not exceed 30 mg/L determined monthly,
based on the arithmetic mean of all samples
collected during the month.
Total Suspended
Solids
24-hour composite,
collected at least
daily2
Shall not exceed 30 mg/L, determined monthly,
based on the arithmetic mean of all samples
collected during the month.
Total Coliforms
Grab, collected at
least daily
Compliance determined daily, based on the
median value determined from the
bacteriological results of the last 7 days for
which analyses have been completed.
Turbidity
Continuous
recording
turbidimeter
Filtered wastewater shall not exceed an average
operating turbidity of 2 NTU, determined
monthly, and not exceeded 5 NTU at any time.
Dissolved
Oxygen
Grab, collected at
least daily
Shall contain dissolved oxygen.
I Source: "Evolution of the Water Reuse Regulations in Washington State "
2 TSS sampling may be reduced for those projects generating Class A reclaimed water on a case-by-case
basis by WDOH and WDOE.
In addition, the Washington reuse standards include requirements for treatment reliability
to prevent the distribution of any reclaimed water that may not be adequately treated
because of a process upset, power outage, or equipment failure. Reliability requirements
include provisions for alarms, standby power supplies, multiple or standby unit treatment
processes, emergency storage or disposal provisions, and standby replacement equipment.
The standards for irrigation, commercial, and industrial reuse are covered under the
general requirements. Requirements for the traditional reclaimed water uses in the
general section of the standards are primarily based on the protection of public health.
Even Class A reclaimed water used for irrigation does not necessarily remove all
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-26
substances (e.g., nitrates). Reclaimed water permits are issued to require that reclaimed
water is applied at agronomic rates to protect ground water quality and meet public health
laws. Treatment and quality requirements for reclaimed water used for irrigation are
presented in Table 2-10. Washington does not have specific unrestricted recreational
reuse regulations for reclaimed water.
Table 2-10
Washington State Treatment and Quality Requirements
for Reclaimed Water'
Type of Reclaimed Water Allowed
Use
Class A
Class B
Class C
Class D
Irrigation of Nonfood Crops
Trees and Fodder, Fiber, and Seed Crops
Sod, Ornamental Plants for Commercial Use, and Pasture
to Which Milking Cows or Goats Have Access
YES
YES
YES
YES
YES
YES
YES
NO
Irrigation of Food Crops
Spray Irrigation
All Food Crops
Food Crops Which Undergo Physical or
Chemical Processing Sufficient to
Destroy All Pathogenic Agents
YES
YES
NO
YES
NO
YES
NO
YES
Surface Irrigation
Food Crops Where There is No
Reclaimed Water Contact With
Edible Portion of Crop
Root Crops
Orchards and Vineyards
Food Crops Which Undergo Physical or
Chemical Processing Sufficient to
Destroy All Pathogenic Agents
YES
YES
YES
YES
YES
NO
YES
YES
NO
NO
YES
YES
NO
NO
YES
YES
Landscape Irrigation
Restricted Access Areas (e.g., Cemeteries and Freeway
Landscapes)
YES
YES
YES
NO
Open Access Areas (e.g., Golf Courses, Parks,
Playgrounds, School yards, and Residential
Landscapes)
YES
NO
NO
NO
Source: "Evolution of the Water Reuse Regulations in Washington State "
2.10.3 Regional Water Reuse
Reuse of wastewater in the Yakima metropolitan area may become economically and
politically feasible as the availability of irrigation water declines. The majority of the
crops in the valley are food crops which require Class B water for surface irrigation and
Class A water for spray irrigation. Other uses of Class A water could be the irrigation of
yards, schoolyards, golf courses, playgrounds, and parks. The City of Yakima's irrigation
system utilizes local surface water.
Based on the plant's data on total coliform, Yakima's wastewater effluent would most
likely be classified as Class D reuse water. In order to incorporate wastewater reuse to
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-27
the fullest extent, it is necessary to upgrade the treatment process to generate Class A
reclaimed water, which would require installing filtration to the treatment plant upstream
of chlorination, along with the necessary in-line pump station and recycled water pump
station.
Converting to Class A reuse water would not be cost effective at this time as treated
wastewater would likely require a greater level of treatment than is currently being
provided for the City's potable water supply. An initial estimate of probable cost to
provide added treatment for Class A wastewater reuse is $6 M in capital cost, primarily
for a coagulation/filtration system and in -plant pumping. This figure does not include a
distribution system for transporting reuse water from the treatment plant to the end user,
and does not include ongoing operational costs associated with potential coagulant feed,
increased disinfection chemical usage, and pumping costs.
As the residential and industrial base of the City's service area expands there may be
opportunities for using reuse water. Irrigation of parks, yards, and golf courses could be
the initial consumers of the reuse water, especially the portions of the service area that are
not being served with irrigation water. When a viable customer base or a large industrial
user is established, the City will investigate the feasibility of treating and transporting
reuse water to the end user.
2.11 Wetlands for Wastewater Treatment
In improving wastewater effluent quality, many communities have considered wetlands
treatment. Wetlands can reduce ammonia and total nitrogen, in addition to providing
metals reduction, wildlife habitat, public education and recreation. With anticipated
increases in nutrient removal requirements, wetland treatment of wastewater is an
alternative that may be considered. However, because wetlands are natural treatment
systems influenced by different variables such as climatic changes and the physical
condition of the wetlands, operators have limited control over the process.
The impact of wetland treatment on effluent temperature is also a factor to consider.
During the hottest time of day, on the hottest days of the year, open -water wetland
systems can potentially act as solar collectors, increasing effluent temperature. This
affect can possibly be mitigated by shaded or below -ground -surface wetland construction.
2.12 Land Application of Food Processing Waste
The City has discontinued its sprayfield operation for treatment and disposal of food
processing waste. The new NPDES permit does not authorize process wastewater
discharges to the sprayfield.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-28
2.13 Endangered Species
Tables 2-11, 2-12 and 2-13 summarize information regarding endangered, threatened, and
candidate species for the study area provided by the U.S. Fish and Wildlife Service, and
the Washington Department of Fish and Wildlife. The Washington Natural Heritage
Information System stores and updates information regarding rare, threatened, or
endangered plant species in the state.
The categories (from 50 CFR 17.11 and 17.12) used to describe federal status are the
same for plants and animals.
Listed Endangered: Taxa in danger of extinction throughout all or a significant portion
of their range;
Listed Threatened: Taxa likely to be classified as Endangered within the foreseeable
future throughout all or a significant portion of their range.
Candidate Species of plants and animals are defined in Federal Register 56:58804-58836;
November 21, 1991:
Category 1: Taxa for which the U.S. Fish and Wildlife Service currently has
substantial information on hand to support the biological appropriateness
of proposing to list as Endangered or Threatened. Proposed rules have not
been issued, but development and publication of such rules are anticipated;
Category 2: Taxa for which information now in possession of the U.S. Fish and
Wildlife Service indicates that proposing to list as Endangered or
Threatened is possibly appropriate, but for which conclusive data on
biological vulnerability and threat are not currently available to support
proposed rules. Further biological research and field study may be needed
to ascertain the status of taxa in this category.
The federal register also defines designations of proposed endangered and proposed
threatened, pertaining to taxa for which there is no current listing, but rulemaking is in
progress.
Plants identified for protection by the Washington Department of Natural Resources are
given in Table 2-11. The operation of wastewater treatment facilities is not likely to
affect the viability of the plant species listed in Table 2-11.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-29
Table 2-11
Plant Listing
Scientific
Name
Common
Name
State
Status
Federal
Status
Allium diction
Blue Mountain onion
Threatened
Artemisia campestris
Northern wormwood
Endangered
Astragahis cohnnbianus
Columbia milk -vetch
Threatened
Astragalus australis
Cotton's milk -vetch
Threatened
Astragalus pulsiferae
Ames' milk -vetch
Endangered
Astragalus sinuatus
Whited's milk -vetch
Endangered
Calochortus nitidus
Broad -fruit mariposa
Threatened
Camissonia pygmaea
Dwarf evening -primrose
Threatened
Castilleja levisecta
Golden paintbrush
Endangered
T
Cimiciftrga elata
Tall bugbane
Threatened
Corydalis aquae-gelidae
Clackamas corydalis
Threatened
Cusickiella douglasii
Douglas' draba
Threatened
Cypripediunt parviflorton
Yellow lady's-slipper
Endangered
Delphinium leucophaeum
Pale larkspur
Endangered
Delphinium viridescens
Wenatchee larkspur
Threatened
Dodecatheon austrofiigidum
Frigid shootingstar
Threatened
Eatonella nivea
White eatonella
Threatened
Erigeron basalticus
Basalt daisy
Threatened
Erigeron howellii
Howell's daisy
Threatened
Erigeron oreganus
Gorge daisy
Threatened
Eriogonum codiurn
Umtanum desert buckwheat
Endangered
Eryngiunt petiolattnn
Oregon coyote -thistle
Threatened
Filipendula occidentalis
Queen -of -the -forest
Threatened
Hackelia venusta
Showy stickseed
Endangered
Haplopappus liatriformis
Palouse goldenweed
Threatened
Howellia aquatilis
Howellia
Threatened
T
Juncus kelloggii
Kellogg's rush
Threatened
Juncus tiehmii
Tiehm's rush
Threatened
Lathyrus holochlorus
Thin -leaved peavine
Threatened
Lathyrus torreyi
Torrey's peavine
Threatened
Lesquerella tuplashensis
White Bluffs bladderpod
Endangered
Liparis loeselii
Twayblade
Endangered
Lobelia dortmanna
Water lobelia
Threatened
Lobelia kahnii
Kalm's lobelia
Endangered
Loeflingia squarrosa
Loeflingia
Threatened
Lomatium bradshawii
Bradshaw's Iomatium
Endangered
E
Lomatium rollinsii
Rollins' desert -parsley
Threatened
Lomatium tuberosum
Hoover's desert -parsley
Threatened
Lupinus stdphureus
Kincaid's sulfur lupine
Endangered
Lupinus sabinei
Sabin's lupine
Endangered
Meconella oregana
White meconella
Threatened
Navarretia tagetina
Marigold navarretia
Threatened
Ophioglossum pusilltun
Adder's-tongue
Threatened
Orthocarpus bracteosus
Rosy owl -clover
Threatened
Ovytropis campestris
Columbia crazyweed
Threatened
Oxytropis campestris
Wanapum crazyweed
Endangered
Penstemon barrettiae
Barrett's beardtongue
Threatened
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 2-30
Table 2-11
Plant Listing
Scientific
Name
Common
Name
State
Status
Federal
Status
Petrophyton cinerascens
Chelan rockmat
Threatened
Phacelia lenta
Sticky phacelia
Threatened
Platanthera chorisiana
Choris' bog -orchid
Threatened
Poa laxora
Loose -flowered bluegrass
Threatened
Poa unilateralis
Ocean -bluff bluegrass
Threatened
Polemonium carneam
Great polemonium
Threatened
Polemonium pectination
Washington polemonium
Threatened
Ranunculus reconditus
Obscure buttercup
Threatened
Rorippa columbiae
Persistentsepal yellowcress
Threatened
Rubus nigerrimus
Northwest raspberry
Endangered
Salix sessilifolia
Soft -leaved willow
Threatened
Sidalcea hirtipes
Hairy -stemmed checker -mallow
Endangered
Sidalcea malvora
Rose checker -mallow
Endangered
Sidalcea nelsoniana
Nelson's checker -mallow
Endangered
T
Sidalcea oregano
Oregon checker -mallow
Endangered
E
Silene seelyi
Seely's silene
Threatened
Silene spaldingii
Spalding's silene
Threatened
Sisyrinchium sarmentosum
Pale blue-eyed grass
Threatened
Spiranthes dihivialis
Ute ladies'tresses
Endangered
T
Sullivantia oregano
Oregon sullivantia
Threatened
Aster borealis
Rush aster
Endangered
Aster jessicae
Jessica's aster
Endangered
Tauschia hooveri
Hoover's tauschia
Threatened
Trifolium thompsonii
Thompson's clover
Threatened
SC = Species of Concern E = Endangered
C = Candidate T = Threatened
The animals and fish identified for protection by the U.S. Fish and Wildlife Service and
Washington Fish and Wildlife are presented in Table 2-12 and Table 2-13.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-31
Table 2-12
Animal Listing
Common
Name
Scientific
Name
State
Status
Federal
Status
Gray Wolf
Canis lupus
E
T
Grizzly Bear
Ursus arctos
E
T
Fisher
Martes pennanti
E
SC
Columbian white-tailed deer
Odocoileus virginianus leucurus
E
E
Woodland caribou
Rangifer tarandus
E
E
American White Pelican
Pelecanus erythrorhynchos
E
Brown Pelican
Pelecanus occidentalis
E
E
Sandhill Crane
Grus canadensis
E
Snowy Plover
Charadrius alexandrinus
E
T
Spotted Owl
Strix occidentalis
E
T
Western Gray Squirrel
Sciurus griseus
T
SC
Lynx
Lynx canadensis
T
T
Aleutian Canada Goose
Branca canadensis leucopareia
T
SC
Bald Eagle
Haliaeetus leucocephalus
T
T
Ferruginous Hawk
Buteo regalis
T
SC
Sage Grouse
Centrocercus urophasianus
T
SC
Sharp -tailed Grouse
Tympanuchus phasianellus
T
SC
Upland Sandpiper
Bartramia longicauda
E
Marbled Murrelet
Brachyramphus marmoratus
T
T
Western Pond Turtle
Clemmys inamorata
E
SC
Oregon Silverspot Butterfly
Speyeria zerene hippolyta
E
T
Mardon Skipper
Polites mardon
E
C
Northern Leopard Frog
Rana pipiens
E
SC
Oregon Spotted Frog
Rana pretiosa
E
C
Pygmy Rabbit
Brachylagus idahoensis
E
E
E = Endangered
T = Threatened
SC = Species of Concern
PT = Proposed Threatened
C = Candidate
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-32
Table 2-13
Fish Listing
Common
Name
Scientific
Name
State
Status
Federal
Status
Chum Salmon (Hood Canal)
Oncorhynchus keta
C
T
Chum Salmon (Lower Columbia)
Oncorhynchus keta
C
T
Sockeye Salmon (Lake Ozette)
Oncorhynchus nerka
C
T
Sockeye Salmon (Snake River)
Oncorhynchus nerka
C
E
Chinook Salmon (Puget Sound)
Oncorhynchus tshawytscha
C
T
Chinook Salmon (Snake River
Sp/Su)
Oncorhynchus ishawytscha
C
T
Chinook Salmon (Upper Columbia)
Oncorhynchus tshawytscha
C
E
Chinook Salmon (Lower
Columbia)
Oncorhynchus tshawytscha
C
T
Chinook Salmon (Snake River Fall)
Oncorhynchus tshawytscha
C
T
Steelhead (Snake River)
Oncorhynchus nrykiss
C
T
Steelhead (Middle Columbia)
Oncorhynchus mykiss
C
T
Steelhead (Upper Columbia)
Oncorhynchus mykiss
C
E
Steelhead (Lower Columbia)
Oncorhynchus mykiss
C
T
Bull Trout
Salvelinus confiztentus
C
T
Bull Trout (Columbia Basin)
Salvelinus conJuentus
C
T
Eulachon
Thaleichthys pacifrcus
C
River Lamprey
Lampetra ayresi
C
SC
Umatilla Dace
Rhinichthys Umatilla
C
E = Endangered
C = Candidate
SC = Species of Concern
T = Threatened
The Fish and Wildlife Service suggests that a Biological Assessment (BA) be conducted
if listed species are located in the study area. Sections 7(a) and 7(c) of the Endangered
Species Act outline the responsibilities of Federal agencies or their designees conducting
operations in areas with endangered and threatened species. Prior to any major
construction activity, a Biological Assessment (BA) must be conducted to determine the
effect of the proposed action on the endangered species. Even though wastewater
discharge may affect vegetation on the banks of the Yakima River and may affect aquatic
life in the River, it is anticipated that a BA will show that the wastewater discharge would
have no significant affect on the endangered species in the area.
2.14 Washington Salmon Recovery
Historically, the Yakima River is reported to have supported a substantial salmon fishery
resource. Prior to 1880, anadromous runs in the Yakima River Basin were estimated to
be more than one-half million fish and included, among others, sockeye salmon, summer
steelhead, and spring Chinook runs. The anadromous fish runs have either disappeared or
have been greatly reduced in the Yakima system. The Washington Department of Fish
and Wildlife is working to protect and restore wild salmon to sustainable levels. An
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-33
unsuccessful Washington State legislative initiative, SB -5289, proposed stringent water
quality and water quantity policies with regard to salmon recovery which, if enacted,
would have had significant impact on municipal wastewater discharges. Some possible
results of a future successful salmon bill for the Yakima Regional WWTP are as follows:
• Likely to require tertiary treatment of wastewater effluent for removal of
phosphorus and for filtration prior to discharge.
• Likely to require increased operating costs of the wastewater treatment facilities
(7.5 additional personnel at an estimated cost of $562,500± plus $250,000± per
year in chemical, electrical, etc.).
• Increased cost in preparation of sewerage system plans to incorporate reuse
(Estimated cost - $200,000±).
• Participation in watershed planning (Estimated cost - $200,000±).
• May result in loss of exclusive right to reclaimed water if the City decided to
undertake reclamation and/or effluent reuse.
• May result in loss of any reclamation of wastewater effluent to instream flow.
• Accelerate implementation of stormwater program.
2.15 Pretreatment
In 1972, the Clean Water Act was enacted to clean up the waters of the United States. In
1977, the Act was amended and expanded. As part of the amendments, 40 CFR 403.8 (a)
requires that any publicly owned treatment works (POTW) with an average daily flow of
greater than 5 MGD develop a Pretreatment Program.
Prior to April 30, 2000, the WDOE has been delegated authority to administer the
National Pretreatment Program in the State of Washington. Publicly -owned treatment
works (POTWs) in the State of Washington are required to implement a Pretreatment
Program in accordance with USEPA Federal pretreatment regulations. The purpose of
pretreatment regulations is to protect wastewater collection, treatment facilities, and
workers from hazardous or deleterious discharges from industrial users discharging to the
public facilities. Through prohibitions on non-domestic users, the pretreatment
regulations prevent dischargers from introducing pollutants into the POTW which alone,
or in conjunction with other discharges, may cause interference (i.e. disrupt the treatment
process, resulting in violation of the effluent limitation) or pass through the treatment
facilities in quantities that could cause NPDES permit violations. In addition, the
pretreatment regulations will not allow discharges which, in combination with other
discharges, would cause the sewage biosolids to exceed criteria for land application.
On October 13, 1993 the City of Yakima was issued Compliance Order DE93WQ-C492
by WDOE. This Compliance Order required the City to further develop portions of the
City's Pretreatment Program, and to "request" partial delegation of the Pretreatment
Program. WDOE was responsible for writing and managing permits and any
enforcement action. The City was responsible for inspections and monitoring of the
business community.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-34
As a result of Initiative 607 (prior to I-695), WDOE had a cap on permit fee increases.
Increased demand for services, coupled with limited funding increases, led WDOE to
delegate and partially delegate Pretreatment Programs wherever possible.
During negotiation for the City's 1997 NPDES permit, the initially proposed pretreatment
requirements were unacceptable to the City. In addition to the requirements already in
place, the City would have been required to develop legally binding discharge
authorizations with each business. The list of requirements made these authorizations
indistinguishable from State Waste Discharge (SWD) permits. There was no
corresponding authority to charge the business community fees to cover the additional
resource requirements. The City would have been responsible for informing the business
community of changes in Federal and State pretreatment regulations and responsible for
enforcement actions. In other words, the City had to make a choice between carrying out
all the functions of a fully delegated Pretreatment Program, without the ability to collect
permit fees, or to become fully delegated and collect those permit fees. The City agreed
to accept full delegation.
On September 8, 1997, WDOE issued the Yakima Regional WWTP NPDES Permit
number WA -002402-3. As a condition of this permit, the City was required to request
full delegation of the Pretreatment Program by July 1, 2000. WDOE received the City's
application for full pretreatment authority on June 30, 2000. WDOE approved the
application, and with the issuance of the NPDES Permit No. WA -002402-3, on June 1,
2003, formally authorized the City to implement its local pretreatment program effective
June 15, 2003.
The requirements of what the City is responsible for implementing full pretreatment are
described in the appended NPDES permit. One of the major requirements the City needs
to fulfill is the submission of an annual pretreatment report. The report must include an
industrial user survey to determine the extent of compliance of all industrial users of the
sanitary sewer and wastewater treatment facility with Federal pretreatment regulations (40
CFR Part 403 and Sections 307 (b) and 308 of the Clean Water Act), with State
regulations (Chapter 90.48 RCW and Chapter 173-216 WAC) and with local ordinances.
A summary of the current Significant Industrial Users (SIUs) registered with the City is
shown in Table 2-14.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-35
Table 2-14
Permitted Significant Industrial Users,
City of Yakima
Name of SIU
SIC Number
1
Boise Cascade
2421, 2436
2
Cintas
7218
3
CM Holtzinger (6`" Ave.)
0723
4
Columbia Reach Pack
0723
5
Congdon Orchards
0723
6
Del Monte
2033
7
Evans Fruit
0723
8
Finish Line
3471, 3479
9
Hansen Fruit
0723
10
Hops Extract
2087
11
Inland -Joseph Fruit
0723
12
Jack Frost Fruit
0723
13
John I. Haas (International CO2 Extraction)
2087, 2048
14
Lancaster/Pyramid Orchards
0723 _
15
Longview Fibre
2653
16
Michelsen Packaging
2679
17
Noel Canning _
2086 _
18
Orchard -Rite
3511, 5209,
3479
19
Prentice Fruit
0723
20
Roche Fruit #13
0723
21
Roche Fruit #46
0723
22
Seneca
2099
23
Snokist Growers
0723
24
U.S. Syntec
2841
25
Voelker Fruit
0723
26
Washington Fruit (1st Ave.)
0723
27
Yakima Brewery
2082
WDOE and the City will work together on permits for facilities which require more than
one permit for discharges to surface waters (NPDES permits), to ground water (State
permits), or to the sewer (State/Pretreatment permits, or General Permits) in order to
ensure that all waste streams requiring permits are covered with the least duplication of
effort.
The Yakima Regional WWTP currently provides wastewater treatment to the Terrace
Heights Sewer District and the City of Union Gap through a multi-party agreement (the
parties being the City, Yakima County, Terrace Heights Sewer District and the City of
Union Gap). Through additional special agreement, the Terrace Heights Sewer District
and the City of Union Gap were required to develop delegated Pretreatment Programs of
their own as part of the requirements set forth in the Yakima Regional WWTP NPDES
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-36
permit. The City of Yakima is required to independently verify compliance by the
businesses in those jurisdictions. There are a minor amount of permittees in Terrace
Heights and in Union Gap that must be monitored.
2.16 Air Pollution
The emission of air pollutants is regulated under the Federal Clean Air Act Amendments
of 1990 and is administered in the Yakima area by the Yakima Regional Clean Air
Authority.
2.16.1 The Clean Air Act and Rules for the Control of Air Pollution in
Washington
The Clean Air Act includes national air quality standards for Criteria pollutants including
nitrous oxides (NO,), volatile organic compounds (VOCs), particulate matter of diameter
less than 10 µm (PMio), total suspended particulate (TSP), sulfur oxides (S0,), ozone
(03), carbon monoxide (CO), and lead (Pb). Hazardous air pollutants which "present, or
may present, through inhalation or other routes of exposure, a threat of adverse human
health effects or adverse environmental effects" are also included in section 112(b)(2) of
the Clean Air Act. Hazardous air pollutants that may be released from wastewater
treatment facilities include hydrogen sulfide (H2S), chlorine, and specific VOCs such as
benzene. Other criteria pollutants can be of concern when engine generators are present.
Each year the Yakima Clean Air Authority requires sources of air contaminants to register
and obtain a permit. They are required to fill out a registration questionnaire that
delineates the emissions from their facilities. A registration fee is paid to the Authority
based on the level of potential controlled and uncontrolled emissions. In order to predict
the emissions from the Yakima Regional WWTP, an air emissions model, the Water 8
Model from EPA, was utilized in 1996. The model run estimated air emissions from the
facility at 609 lbs per year. This was well below the threshold for Title V permitting,
which is 25 tons per year. The Yakima Regional WWTP is not regarded as a major
source and is not subject to Title V permitting.
If the Yakima Regional WWTP were regulated as a major source because of new rules
being proposed by EPA (Urban Air Hazardous Air Pollution), some method of emission
reduction may need to be employed. The draft Urban Air Hazardous Air Pollution
regulation is scheduled for promulgation in 2004. Section 112 of the Clean Air Act
addresses this issue, stating:
"The maximum degree of reduction in emissions that is deemed achievable
for new sources in a category or subcategory shall not be less stringent than
the emission control that is achieved in practice by the best controlled
similar source, as determined by the Administrator. Emission standards
promulgated under this subsection for existing sources in a category or
subcategory may be less stringent than standards for new sources in the same
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-37
category or subcategory but shall not be less stringent, and may be more
stringent than:
(A) the average emissions limitation achieved by the best performing 12
percent of the existing sources [with some restrictions on sources
considered], in the category or subcategory for categories and
subcategories with 30 or more sources, or
(B) the average emission limitation achieved by the best performing 5
sources in the category or subcategory for categories or subcategories
with fewer than 30 sources."
The emission standards enforced under Section 112 are referred to as MACT (maximum
available control technology) standards, and take into consideration the cost of achieving
the emissions and the non -air quality health, environmental impacts, and energy
requirements. The Clean Air Act Amendments set November of 1996 as a date for the
promulgation of MACT standards for POTWs.
Hydrogen sulfide emissions from facilities are dependent on the influent H2S
concentration, the influent dissolved oxygen concentration, and the unit processes in the
treatment stream. The influent H2S concentration is itself a factor of the ambient
temperature in the collection system, since the metabolic rate of bacteria producing I -12S
decreases as temperature decreases. H2S has recently been removed from the list of
hazardous pollutants in the Clean Air Act.
The Yakima Regional WWTP uses chlorine for disinfection and process uses. The
likelihood of significant chlorine emissions from the wastewater treatment facilities is
low as long as chlorine is properly stored and applied. The solubility of chlorine in water
at 85°F and one atmosphere is roughly 5,600 mg/1 (White2 1992), and increases with
decreasing temperature. At the maximum concentration in the wastewater process streams
of 12 mg/l, and an average annual temperature of 50°F such as found at the Yakima
Regional WWTP, it is unlikely that the chlorine will volatilize. Potential air quality
problems would be associated with ruptures or leaks in the chlorine tanks or piping.
These situations are discussed in more detail in subsequent sections.
2.16.2 Clean Air Act Risk Management Plans
Section 112(r) of the Clean Air Act requires that provisions be made for risk management
plans to prevent and minimize consequences of any release of a hazardous substance.
The regulation was codified on June 20, 1996 as 40 CFR Part 68 and titled Accidental
Release Prevention Provisions. The regulation established a Risk Management Plan
(RMP) submittal deadline of June 21, 1999 and subsequent five year resubmission
deadlines. Facilities which store regulated chemicals above the threshold quantity are
2 White, George Clifford, "The Handbook of Chlorination and Alternative Disinfectants," Third Edition,
1992.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-38
subject to the rule. The Yakima Regional WWTP has submitted the Risk Management
Plan and received a completeness letter from EPA. Only chlorine and sulfur dioxide are
stored in quantities higher than the threshold values at the Yakima facility. A deluge -type
wet scrubber system has been installed to comply with the provisions of the Uniform Fire
Code (UFC), Article 80, described below. The five-year resubmission deadline is June
21, 2004.
2.16.3 Chorine -Specific Regulations
Due to its properties as an oxidant and a toxic chemical, several regulatory bodies have
provisions related to the use, storage, and release of chlorine. The current chlorination
and dechlorination facilities are in compliance with the following rules and regulations.
Regulation: 40 CFR 68
Requirements: Requires that an accidental release prevention program be maintained for
the release of over 1000 lbs of chlorine. The threshold quantity is waived if the toxic
chemical comprises less than one percent by weight of the released substance. The
Yakima Regional WWTP has prepared a Process Safety Management Plan (PSM) which
meets the requirements for an accidental release prevention program.
Regulation: NFPA 820 - Fire Protection in Wastewater Treatment and Collection
Facilities, 1992
Requirements: Chlorine gas is considered a strong oxidizer with a health hazard ranking
of 4 meaning that short exposure could result in death or major residual injury. No
specific requirements are given, but it is recommended that fire and explosion hazards be
mitigated with "a commonly preferred method of copious flushing with air (ventilation)"
(NFPA 820, Section 5-4).
Regulation: Uniform Fire Code, Article 80 -Hazardous Materials
Requirements: Under the UFC, chlorine gas is considered a toxic chemical due to its
health hazard and oxidizing properties, and is regulated when stored above the exempt
amounts listed in Table 2-15.
Table 2-15
Exempt Amounts of Compressed Gases
Conditions
Exempt Amount
(ft3 at STP)
Unprotected by sprinklers, gas cabinets or separate rooms
650
Within gas cabinets in unsprinklered building
1300
In sprinklered building, not in gas cabinets or separate rooms
1300
In sprinklered building, within gas cabinets
2600
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 2-39
Regulation: Uniform Fire Code, Section 80.303.6(a) -(c)
Requirements: Ventilation must be provided through "ventilated storage cabinets,
exhausted enclosures, or within a separate ventilated room without other occupancy or
use." Where gas cabinets are used, they must operate at negative pressure and provide
limited access ports with average face ventilation velocity at the access port of no less
than 200 feet per minute and a minimum at any point of the window of no less than 150
feet per minute. Access ports must be provided with self-closing doors and connected to
an exhaust system. When separate gas storage rooms are used, they must also operate at a
negative pressure and direct the exhaust to an exhaust system.
Regulation: Uniform Fire Code, Section 80.303.6(d)
Requirements: "Treatment systems shall be capable of diluting, adsorbing, absorbing,
containing, neutralizing, burning, or otherwise processing the entire contents of the
largest single tank or cylinder of gas stored or used." By requiring owners or operators to
use the maximum flow from the largest tank for designing scrubber systems, this
regulation determines the flow requirements for scrubbers in wastewater treatment
facilities.
Regulation: Uniform Fire Code, Sections 80.303.7 and 80.307.8
Requirements: A facility storing chlorine gas must be equipped with a continuous gas
detection system with visible and audible alarms, and with emergency power for the gas
detection system, emergency alarm system, temperature control system, and exhaust
ventilation.
Title 29, Part 1910 of the Federal Register regarding process safety management of highly
hazardous chemicals is often referenced by OSHA to regulate the use of chlorine in
wastewater treatment facilities with storage or use above the threshold quantity of 1500
lbs. This regulation requires employers of non-exempt facilities to compile written
process safety information and conduct a process hazard analysis which is updated every
five years. A team knowledgeable in engineering and process operations must then
review this analysis, and the results of the analysis implemented as quickly as possible.
Finally, Part 1910 requires the employer to develop and implement operating procedures
for safe practices regarding each covered process, provide employee training, and
investigate incidents which "resulted in, or could reasonably have resulted in, a
catastrophic release of highly hazardous chemicals in the workplace." As noted
previously, the Yakima Regional WWTP has completed both a process safety
management (PSM) plan and risk management plan (RMP) for the facility.
2.17 Virus Control
The current standard measure of virus control for wastewater treatment plant effluent is
the fecal coliform limit given in each facility's NPDES permit. Fecal coliform limits are
based on water quality protection criteria. Fecal coliform bacteria are used as an indicator
species for virus control due to the lack of an easily implementable analytical method to
test for the presence of infectious viruses. Virus control is a concern due to the potential
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-40
contamination of drinking water and for the protection of beneficial uses of the Yakima
River.
Since viral monitoring is technologically limited, the probability of stricter viral
monitoring requirements for wastewater treatment plants is based on the probability of
the development of an easily implementable viral monitoring technique.
2.18 Noise
The City of Yakima Penal Code, Chapter 6.04, currently regulates noise which may result
in the disturbance of the public. "Noises which unreasonably disturb the comfort, peace,
and repose of the citizens of the City of Yakima are considered to be a detriment to the
public health, comfort, convenience, safety, welfare, and prosperity of the City". Noises
originating or created from commercial and industrial uses, which are lawfully
established and operated, are considered to be exempt from the provisions of the noise
regulations.
Regulations pertaining to noise are not likely to be a concern in future modifications to or
construction of, wastewater treatment facilities. A potential source of noise at the Yakima
Regional WWTP would be the blower equipment. The current blower equipment does
not present noise problems because of its below -grade location. If above -grade
installations of blowers or other noise generating equipment are considered in the future,
compliance with local noise ordinances should be planned for during design.
2.19 Stormwater
On January 9, 1998, the proposed Phase II Stormwater regulations were published in the
federal register. This regulation became final on November 1, 1999. A review of this
regulation has been under discussion by the City Council, including study sessions and
meetings with the City Council about the approach and implementation of a regional
stormwater program.
The City of Yakima is in the process of implementing a regional storm water program
with the City of Union Gap and Yakima County. At this time it has not been decided if
there will be a regional stormwater utility or if all cooperating parties will have their own
utility with some degree of sharing resources. It is not known how much, if any,
responsibility for this implementation will be placed on the Wastewater Division.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 2-41
SECTION 3
SERVICE AREA CHARACTERISTICS
Summary
Section 3 presents existing and projected Yakima Regional WWTP service area
characteristics. With the exception of population projections, much of Section 3 remains
unchanged from the 2000 Draft Facilities Plan. In addition, revisions have been made
for the text and tables regarding Union Gap so that the information coincides with the
City of Union Gap Comprehensive Plan (March 1999) and the General Sewer Plan (June
2000). The 2000 Draft Wastewater Facilities Plan Section 3 is included in the
Attachment and is incorporated by reference other than for the updated sections presented
here.
3.3 Current and Projected Population
The size of wastewater management facilities, including sewers, treatment plants, and
pumping stations, is directly proportional to the population served by the infrastructure.
The City of Yakima and Yakima County expect growth to occur within the Service Area.
To allow consistent planning and shared information, a joint population projection effort
was coordinated through the 1998 Amendments to the Yakima Urban Area
Comprehensive Plan.
A summary of the population projections is provided in Table 3 -la. The projections
approximately correlate with an estimated one percent growth rate for the Service Area,
including the Yakima Urban Service Area, Union Gap Urban Growth Area, Terrace
Heights Urban Service Area, and Yakima Urban Reserve. The table indicates that the
current base service area population of over 93,000 is projected to increase by
approximately 50,000 people within the next 20 years, and by approximately 84,000
people at ultimate buildout. Based upon the growth rate presented in the analysis, it is
anticipated that the current Service Area will approach its population saturation density
within the next 25-30 years.
Based on the projections in Table 3-1a, the percentage of growth in population within the
Service Area will shift away from the City of Yakima to the City of Union Gap, Terrace
Heights, and the Yakima Urban Reserve areas at full buildout. Table 3 -lb identifies the
relative population of the Yakima Urban Service Area, Union Gap Urban Service Area,
Terrace Heights Urban Service Area, and the Yakima Urban Reserve Area for current
population, year 2024, and buildout conditions.
Both the City of Yakima and Yakima County have experienced relatively stable
population growth since the 1960s, averaging approximately 1 percent per year. This
trend is expected to continue in the planning period. Population estimates are derived
from the Office of Financial Management (OFM) for Yakima County and allocated to
each City and its surrounding Urban Growth Area.
CITY OF YAKIMA WASTEWATER FACILITY PLAN - DRAFT 2/26/04
PAGE 3-1
1.iyv'_
Table 3 -la
Projected Residential Population for Wastewater Facilities Service Area
Current
Year
Year
Year
Year
Year
Buildout''
Yakima Urban Service Area
Populations
20052
20102
20152
20202
20242
11.51%
Yakima Urban
82,832
,y, 87,900
96,500
Yakima Urban Reserve
102,000
101,759
106,600
Service Area
--0
_
syr ---�
'1,00,000
Union Gap Urban
5,817
5,978
6,316
6,655
6,993
7,310
20,438
Service
Area/Reserve
Terrace Heights
5,249
6,080
6,770
7,324
8,490
9,378
14,145
Urban Service
Area/Reserve
Subtotal
93,898
99,958
109,586
113,979
117,483
118,447
141,183
Yakima Urban
4,025
5,695
8,704
13,812
23,420
31,936
36,317
Reserve3
_
Total Service
97,923
105,653
118,290
127,791
140,903
150,383
177,5005
Area Population
I Current Population presented is for 2002 based on extrapolation of populatiot data presented in 2000
Draft Wastewater Facilities Plan and revised population data from the City of Union Gap.
2 Projected population numbers using extrapolation of population data taken from 2000 Draft
Wastewater Facilities Plan and revised population data from the City of Union Gap.
3 Future Urban Reserve Populations to be determined through neighborhood planning process.
Anticipated growth to occur within Yakima Urban Service Area or Union Gap Urban Service Area.
4 Developed from an estimate of potential dwelling units for the service area adjusted for right-of-way
and related issues (underbuild factors) and multiplied by 2.5 residents per household.
5 Represents calculated build -out population based on land use area.
Table 3 -lb
Percentage Growth of Service Area Populations
Current
Year 2024
Buildout
Service Area Population
97,922
150,383
177,500
Yakima Urban Service Area
84.59%
67.7%
60.06%
Union Gap Urban Service Area/Reserve
5.94%
4.76%
11.51%
Terrace Heights Urban Service Area/Reserve
5.36%
6.27%
7.97%
Yakima Urban Reserve
4.11%
21.27%
20.46%
The projected population and number of new households required for the projections in
the areas currently served by the Yakima Regional WWTP are summarized in Table 3-2.
The current population of 97,922 may understate the actual population since it includes
the 1998 estimate for the Yakima Urban Service Area and 1996 estimates for the Union
Gap Urban Service Area and the Terrace Heights Urban Service Area.
CITY OF YAKIMA WASTEWATER FACILITY PLAN - DRAFT 2/26/04 PAGE 3-2
Table 3-2
Yakima Wastewater Service and Planning Area Population Projections
Area
Current
Population
Projected
Year 2015
Population
Projected
Year 2024
Population
Planned
Growth
To 2024
Household
Conversion
Factor
Total
Projected
New
Household
om
Yakima Urban
Service Area
82,832'
100,0002
101,759
18,927
2.503
"7�5TI
Union Gap Urban
Service
Area/Reserve
5,8171
6,655
7,310
1,493
2.556
585
Terrace Heights
Urban Service
Area/Reserve
5,249'
7,324$
9,378
4,129
2.559
1,619
Subtotals
93,898
113,979
118,447
24,549
9,775
Yakima Urban
Reserve
4,025
13,812"
31,936
27,911
2.50'
11,164"
Totals
97,923
127,791
150,383
52,460
20,939
I Current Population presented is for 2002 based on extrapolation of population data presented in
2000 Draft Wastewater Facilities Plan and revised population data from the City of Union Gap.
2 2015 High Population Estimate from the 1998 Amendments Yakima Urban Area Comprehensive
Plan, Adopted November 24,1998, 21,013 assigned to existing Urban Service Area and 10,812
to Yakima Urban Reserve.
3 From the Yakima Urban Area Comprehensive Plan, adopted April 1997.
'' 2000 Population Estimate from the Washington State Office of Financial Management (2003).
5 2015 Population Estimate assumed an annual increase of 1.23%.
6 From the City of Union Gap Comprehensive Plan, March 1999.
7 1996 Population Estimate from the Terrace Heights Neighborhood Plan, Neighborhood Review
Draft, December 1997.
8 Adjusted from 2016 population estimate from the Terrace Heights General Sewer Nan, March
1998 — high estimate is 14,145.
9 From the Terrace Heights General Sewer Plan, March 1998.
10 From the Yakima Urban Area Comprehensive Plan, adopted April 1997.
11 Anticipated growth within the Yakima Urban Reserve accounted for in the Yakima Urban Service Arca or
Union Gap Urban Service Area.
In accordance with the approved comprehensive plan for each jurisdiction, the projected
build -out population for all areas included in Table 3-2 is approximately 177,500. The
West Valley, Southwest, Terrace Heights, Union Gap and Southeast areas are expected to
accommodate the majority of this increase in population. Sewage flows from the City of
Moxee may be treated at the Yakima Regional WWTP in the future if their separate
treatment facilities become more costly than treatment at the Yakima Regional WWTP.
The Gleed area may also be served by the Yakima Regional WWTP by the year 2015.
CITY OF YAKIMA WASTEWATER FACILITY PLAN - DRAFT 2/26/04
PAGE 3-3
3.11 Current Land Use
Table 3-10 is repeated here for convenience. Table 3-11 is revised as follows based on
the City of Union Gap Comprehensive Plan, March 1999.
Table 3-10
Terrace Heights Urban Growth Area Existing Land Uses'
Existing Land Use
Designation
Number of
Parcels
Acres
Percent
of Total
Vacant
385
1418
32%
SF Residential
1811
1125
25%
Agricultural
136
965
22%
Parks/Open Space
84
458
10%
Commercial
42
157
4%
Wholesale Trade/Industry
45
133
3%
Mining
7
90
2%
Mobile Home Parks
150
85
2%
Education Government
6
21
0%
High Density Residential _
30
10
0%
Duplex/Fourplex
28
7
0%
Federal
8
3
0%
Totals
2732
4472
100%
1 From the Terrace Heights Neighborhood Plan March 1998.
Table 3-11
City of Union Gap Existing Land Use Inventory'
Land Use
Category
Within 1995
City Limits
(acres)
Percent
of City
Acreage
UGA2
(acres)
Total
Acres
Percent of
Total
Acreage
Vacant Land
415
15%
178
593
10%
(Vacant Developable Land)3
(311)
(11%)
(107)
(418)
(7%)
Agricultural
808
30%
2,341
3,149
55%
Residential
656
24%
447
1,103
19%
Industrial
200
7%
44
244
4%
Commercial
208
8%
0
208
4%
Public Facilities
429
16%
0
429
7%
Total Acres of Land
Including all Vacant Parcels •
2,716
100%
3,010
5,726
100%
Total Acres of Land
Including only Developable
Vacant Parcels
2,612
96%
2,939
5,551
97%
I From the City of Union Gap Comprehensive Plan, March 1999.
2 Varies from City of Union Gap Comprehensive Plan, March 1999 by adding UGA 6 and excluding
UGA 3 and UGA 5 which were annexed into the City of Yakima.
3 Vacant developable land includes a 25 percent reduction within the City limits and 40 percent for the
UGA's. This accounts for the land required for roads and utilities and land not suitable for
development, such as sensitive areas.
CITY OF YAKIMA WASTEWATER FACILITY PLAN - DRAFT 2/26/04
PAGE 3-4
3.13.2 Union Gap Urban Service Area
The City of Union Gap is not within Yakima's Urban Service Area for planning purposes.
However, Union Gap's Urban Service Area is within the Urban Service Boundary of the
Yakima Regional WWTP.
Under an interagency agreement, the Yakima Regional WWTP currently provides
treatment service and some direct collection system service for the City of Union Gap.
Union Gap has a General Sewer Plan dated June 2000. Table 3-13 is reproduced from
the General Sewer Plan and identifies the anticipated population estimates for the City of
Union Gap through buildout of all lands within the Urban Growth Area (UGA) and
Urban Reserve Area of the City as shown in Figure 3-4 of the 2000 Draft Wastewater
Facilities Plan.
Table 3-13
Union Gap UGA Population Estimates for the Planning Period4
Area
1998
Population
2005
Population
2019
Population
Buildout
Population
Union Gap '
5,484
5,976
7,094
7,427
UGA 1 1
207
225
268
2,376
UGA 2
UGA 2 was annexed as the "South Broadway Area".
UGA 3
UGA 3 has been annexed by the City of Yakima
UGA 4 I
654
713
847
6,485
UGA 5
UGA 5 has been annexed by the City of Yakima
UGA 6 2
132
147
182
4,150 (3)
TOTAL
6,477
7,061
8,391
20,438
I Based on the Union Gap Comprehensive Pian population projections for County Low with GMA
shift and growth distributed throughout, the UGA. All populations increased from the 1990
population to each year's population at the plans annual population rate increase of 1.23 percent.
2 The 1998 population for UGA 6 was based on counting residence from a recent aerial photo and
assuming 2.59 people per residence and then increasing the population by a 1.23 percent annual
growth rate.
3 The UGA 6 buildout population is estimated at 64 percent of the UGA 4 buildout population
because the size of UGA 6 land area is 64 percent of the size of UGA 4 land area. Both UGA areas
have similar types of zoning.
' Refer to Union Gap General Sewer Plan for identification of UGA boundaries.
Urban Growth Area 6 and the majority of Urban Growth Areas 1 and 4 lie within the City
of Union Gap Urban Reserve. Table 3-14 is also reproduced from the City of Union Gap
General Sewer Plan and identifies the design wastewater flows and characteristics for
Union Gap through buildout for both existing and future Urban Service Areas.
CITY OF YAKIMA WASTEWATER FACILITY PLAN - DRAFT 2/26/04
PAGE 3-5
Table 3-14
Union Gap Summary of Wastewater Flow Design Criteria
1998
2005
2019
Buildout
Peak Flow At Master
Lift Station 1.2 (mgd)
1.37
1.51
2.73
10.17
Peak Flow At Rudkin
Road Lift Station 2 (mgd)
1.76
2.26
4.71
12.86
Max. Month Flow at
YRWWTP 3'4 (mgd)
0.76
0.98
2.03
5.64
BOD Maximum Month
Lb/Day
2,022
2,486
5,513
18,528
TSS Maximum Month
Lb/Day
1,926
2,368
5,253
12,883
I Assumes that All UGA areas contribute flow to the Master Lift Station
2 Assumes a Peak Hour Peaking Factor of 2.9
3 Assumes a Max. Month Peaking Factor of 1.17
4 Does not incorporate an inflow allowance
3.13.3 Terrace Heights Urban Service Area
Terrace Heights is within the greater Urban Service Boundary but constitutes its own
service area. Terrace Heights, while unincorporated, is served by the Terrace Heights
Sewer District, which currently is provided sewer treatment service from the Yakima
Regional WWTP through a interagency agreement. The City of Yakima supplies no
direct urban services to the unincorporated Terrace Heights Urban Service Area.
Demand for services in the Terrace Heights Urban Service Area has historically been
localized in the center of the service area boundary. Currently, large developments are in
the planning stages to the north and east of the center of the service area. Development of
the Terrace Heights Urban Service Area boundary to the south and west of Terrace
Heights has been minimal. The Terrace Heights Sewer District has prepared a General
Sewer Plan dated March 1998. Table 3-15 is reproduced from the General Sewer Plan
and identifies anticipated population estimates, wastewater flow, and wastewater
characteristics for Terrace Heights through 2016. As noted in the Table, Terrace Heights
has projected growth rates of both 3 percent and 10 percent through 2016. The 10 percent
growth projection would represent approximate buildout conditions for all lands within
the Terrace Heights Urban Service Area.
CITY OF YAKIMA WASTEWATER FACILITY PLAN - DRAFT 2/26/04
PAGE 3-6
Table 3-15
Terrace Heights Design Criteria
Design Criteria
19961
2002
2016
3%
10%
3%
10%
Growth
Growth
Growth
Growth
Sewered Population
4,715
5,564
7,544
7,544
14,145
Per Capita Domestic Flow'
52 gpcd
66 gpcd
66 cd
66 cd
66 gpcd
Average Domestic Flow's
171 gpm
255 gpm
346 gpm
346wpm
648 gpm
Average Commercial
30,000
53,600
66,300
66,300
108,500
And Industrial Flow (gpd)5
Peaking Factor6
1.8-3.9
1.8-3.9
1.8-3.9
1.8-3.9
1.8-3.9
Peak Domestic, Commercial,
555
847
1,137
1,137
2,098
And Industrial Flow (gpm)7
Sewered Area (acres)8
1,300
1,570
1,570
2,200
2,200
Infiltration Rate (gpad)
133 9
300
300
300
300
Inflow Rate (gpad)
240 L0
350
350
350
350
Infiltration and Inflow (gpm)11
337
709
709
993
993
Peak Hour Flow (gpm)12
892
1,556
1,846
2,130
3,091
Peak Day Flow (MGD)"
0.732
1.421
1.686
1.945
2.825
Maximum Monthly Flow (MGD)'''
0.490
0.965
1.145
1.321
1.919
Peak Hour Flow (MGD)15
1.284
2.241
2.658
3.067
4.451
BOD Maximum Day (Ib/day)16
1,032
1,217
1,697
1,697
3,096
BOD Maximum Month (Ib/day)17
670
791
1,072
1,072
2,010
SS Maximum Day (1b/day)16
887
1,047
1,459
1,459
2,661
SS Maximum Month (Ib/day)17
704
829
1,155
1,155
2,107
1 1996 data based on totalized flow meter from Lift S ation No. 1.
2 Sewered Population taken from Table 2-6.
3 The residential wastewater contribution on December 31, 1996 was less than the average annual per capita flow.
Average Domestic Flow = (l'er Capita Domestic Flow) x (Sewered Population) / 1440 gpm/gpd.
5 The average commercial and industrial flow is based on increases proportional to the sewered population.
6 Peaking factors in the system range from 2.2 to 3.9 depending on truck sewer pipe. Peaking factors at Lift Station
No. 1 ranged from 1.8 to 2.9 over the last six years. A peaking factor of 2.9 is used in this Plan.
7 Peak flow as measured at Lift Station No. 1 from domestic, commercial, and industrial sources, based on a
peaking factor of 2.9, the highest peaking factor recorded in the last six years at Lift Station No. 1.
8 Sewered areas were determined using digital drafting techniques for planned areas of growth.
9 Based on 1996 Average Summer Flow infiltration from diurnal curves.
10 Based on December 31, 1996 — January 1, 1997 peak stone event.
11 Infiltration and Inflow (gpm) = (Inflow in gpad + Infiltration in gpad) x (Sewered Arca in acres) / (1,440).
12 Peak Hour Flow = (Peak Domestic, Commercial, and Industrial Flow) + (Infiltration and Inflow).
13 Peak Day Flow = [(Pop.) x(Per Capita Flow) + (Com.)] x (1.84) + [(1/1) x (Sewered Area) x (1.84) / (2.9)].
14 Max Month Flow = [(Pop.) x (Per Capita Flow) + (Com.)] x (1.25) + (I/1)x (Sewered Area) x (1.25) / (2.9).
15 Peak Hour Flow (MGD) = (Peak Hour Flow in gpm) x (1,440) / (1,000,000).
16 Based on a weighted average of the 1996 peak day 130D and SS and projected population.
17 Based on a weighted average of the 1996 maximum monthly 130D and SS and projected population
(BOD = 164 mg/I; TSS = 172 mgll)
CITY OF YAKIMA WASTEWATER FACILITY PLAN - DRAFT 2/26/04
PAGE 3-7
3.14 Future Land Use
Table 3-18 is revised to reflect updates in the Union Gap Urban Growth Area/Reserve
information as provided by the City of Union Gap.
3.15.4 Union Gap Urban Service Area
The population of the City of Union Gap is projected to increase to approximately 6,793
persons from the present population of 5,655 by the year 2018. This is a low population
estimate based on a 1.23% annual increase per the City of Union Gap General Sewer
Plan, June 2000. The boundary of the Union Gap Urban Service Area is not expected to
change before 2015 and is in the most part the boundary specified by the 4 Party
Agreement. The Comprehensive Plan and zoning maps will help to control the future
development of Union Gap Service Area through the year 2015 and beyond. The build-
out population for the City of Union Gap existing and reserve Urban Growth Areas is
approximately 20,438 persons and is not expected to be reached until 2050 or beyond.
CITY OF YAKIMA WASTEWATER FACILITY PLAN - DRAFT 2/26/04 PAGE 3-8
Table 3-18
Wastewater Service Area Boundary Summary of Potential New Dwelling Units
Land Use Type
Total
Vacant Acres
Net
Vacant Acres
Density
Factor
Potential New
Dwelling Units
Yakima Urban Service Area
Low Density Residential
2,447
1,8351,2
4
7,340
Medium Density Residential
291
218'
8
1,744
High Density Residential
218
164'
12
1,968
Subtotals
2,956
2,217
11,052
Yakima Urban Reserve
Low Density Residential
6,000
3,500'
4
14,000
Subtotals
6,000
3,500
14,000
Union Gap Urban Growth
Arca/Reserve
Low Density Residential'
5934
4134
3
1,254
Subtotals
593
413
1,254
Terrace Heights Urban
Growth Area/Reserve
Low Density Residential6
1,418
1,064'
4
4,256
Medium Density Residential
92
69'
8
522
High Density Residential
10
8'
12
96
Subtotals
1,520
1,141
4,904
Totals
11,069
7,271
31,210
1
2
3
4
5
6
Reduced 25 percent for Rights -of -Way.
Adjusted to exclude 275 acres of land in public use.
Reduced 40 percent for Rights -of -Way, railways and rivers.
Includes reduction of 25 percent for land in City limits and 40 percent outside of the City limits.
From Table 3-11.
The average density of residential development in Union Gap is three dwelling units per acre. From
the City of Union Gap Comprehensive Plan, March 1999.
All vacant residential land except multi -family would be developed at an average density of four units per acre.
3.15.4 Union Gap Urban Service Area
The population of the City of Union Gap is projected to increase to approximately 6,793
persons from the present population of 5,655 by the year 2018. This is a low population
estimate based on a 1.23% annual increase per the City of Union Gap General Sewer
Plan, June 2000. The boundary of the Union Gap Urban Service Area is not expected to
change before 2015 and is in the most part the boundary specified by the 4 Party
Agreement. The Comprehensive Plan and zoning maps will help to control the future
development of Union Gap Service Area through the year 2015 and beyond. The build-
out population for the City of Union Gap existing and reserve Urban Growth Areas is
approximately 20,438 persons and is not expected to be reached until 2050 or beyond.
CITY OF YAKIMA WASTEWATER FACILITY PLAN - DRAFT 2/26/04 PAGE 3-8
3.15.5 Terrace Heights Urban Service Area
Two boundaries will help to define the future service area. The Urban Growth Boundary,
set by Yakima County, identifies areas that may be served by utilities within 20 years.
The second boundary, the Four Party Agreement (4PA), defines the area that the Terrace
Heights Sewer District may serve as mutually agreed upon by Yakima County, the City of
Yakima, the City of Union Gap, and the Terrace Heights Sewer District. Residents
currently located outside the service area boundary, but inside the Four Party Agreement
boundary are currently served by septic or private systems, but can choose to be served by
Terrace Heights Sewer District. This connection is restricted in areas with low
population densities. The current service area boundary has been expanded to
accommodate all of the known developments that are scheduled for the next 20 years.
The population of the Terrace Heights Sewer District is expected to increase from 4,715
to approximately 7,324 in 2015. The build -out population within the Terrace Heights
existing and reserve Urban Growth Area is approximately 14,145 persons and is not
expected to be reached until 2050 or beyond.
CITY OF YAKIMA WASTEWATER FACILITY PLAN - DRAFT 2/26/04 PAGE 3-9
DRAFT
City of Yakima
Mandatory Wastewater Facilities Plan
SECTION 3
Existing and Projected Service
Area Characteristics
October 2000
prepared by
Clint Dolsby
HDR Engineering, Inc.
reviewed by
John Koch
Tony Krutsch
City of Yakima
DRAFT
Table of Contents
3.1 Introduction 1
3.2 Location 1
3.2.1 History and Development 2
3.2.2 Sewer Service in the Urban Service Boundary 2
3.3 Current and Projected Population 5
3.4 Climate 6
3.5 Soils 7
3.6 Subsurface Groundwaters 8
3.7 Storm Sewer/Subsurface Drainage System 9
3.8 Existing Water Supply System 9
3.9 Existing Irrigation Supply 11
3.10 Sewage Flows 13
3.10.1 Domestic Sewage Flow 13
3.10.2 Commercial Sewage Flow 13
3.10.3 Institutional Sewage Flow 14
3.10.4 Industrial Sewage Flow 14
3.10.5 Influent Wastewater Flows and Loads 16
3.10.6 Wastewater Flow Comparison 16
3.11 Current Land Use 17
3.12 Drainage Basin Evaluation 19
3.13 Existing Sewer Service Area 23
3.13.1 Yakima Urban Service Area 23
3.13.2 Union Gap Urban Service Area 23
3.13.3 Terrace Heights Urban Service Area 24
3.13.4 Yakima Urban Reserve 26
3.14 Future Land Use 26
3.15 Future Sewer Service Areas 30
3.15.1 GMA Planning 30
3.15.2 Yakima Urban Service Area 31
3.15.3 Yakima Urban Reserve 31
3.15.4 Union Gap Urban Service Area 31
3.15.5 Terrace Heights Urban Service Area 31
3.16 Streams, Creeks and Drainage Ways 32
3.17 Sensitive Areas 33
3.17.1 Wetlands 35
3.17.2 Aquifer Recharge Areas 37
3.17.3 Frequently Flooded Areas 38
3.17.4 Fish and Wildlife Habitat Conservation Areas 38
3.17.5 Geologic Hazards and Risks 39
3.18 Flora and Fauna 41
3.19 Environmental Conditions/Limitations 41
3.19.1 Primary Impacts 42
3.19.2 Secondary Impacts 43
3.19.3 Special Considerations 44
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City of Yakima
SECTION 3
Existing and Projected Service Area
Characteristics
3.1 Introduction
Service Areas identify the boundaries from which wastewater flow from residential,
commercial, industrial, and institutional sources are discharged to the wastewater
collection system.
This section on the existing and projected Yakima Service Area characteristics, describes
the Service Areas served by the Yakima Regional WWTP. Principal Service Area
characteristics such as current and future land use and population are identified, and
requirements for service within the Urban Growth Boundary are described. The sensitive
areas, existing water supply, and existing irrigation supply will be presented. This
analysis of the Yakima Urban Area is based on:
> Literature review of current Service Area agreements, recent sewer plans,
population estimates, and other information.
➢ Interviews and meetings with City staff to identify the maps to be obtained from
the City.
3.2 Location
The City of Yakima is located in the south central part of Washington in the Yakima
River Valley. The City is bounded by the Naches River to the north, the Yakima River to
the east, Ahtanum Valley, Wide Hollow Creek and the City of Union Gap to the south,
and Naches Heights to the northwest.
The City of Yakima provides regional wastewater treatment for the Yakima Urban Area,
including the City of Yakima, City of Union Gap, unincorporated lands to the east of the
Yakima River referred to as Terrace Heights, and several other unincorporated areas
under the jurisdiction of Yakima County. The Yakima Regional Wastewater Treatment
Plant (WWTP) may eventually provide service to the community of Gleed, located five
miles northwest of the current City limits, and the City of Moxee, located four miles east
of the current City limits.
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3.2.1 History and Development
Prior to the settlement of the Yakima Valley in the late 1800's, the seminomadic Yakama
Indians that used the land for hunting and gathering of natural food occupied the area.
The main economic activity of the early white settlers was raising livestock. In 1886, the
Northern Pacific Trans -Continental Railroad was extended into the valley. With the
railroad came a large investment in irrigation to attract settlers to the area. By 1900, the
Yakima Valley contained the largest irrigated acreage in Washington.
The Yakima Valley is among the leading agricultural areas in the United States. The
valley is recognized for the production of hops, mint, peas, honey, and several kinds of
tree fruit including apples, peaches, pears, cherries, apricots, prunes and plums.
Early settlement in the Yakima Valley occurred on the level terrain in the vicinity of the
Yakima River. The older residential, commercial, and industrial development of the City
is found in this area. The direction in which City growth was not limited by geographical
constraints was to the west, which has been the primary direction of growth for the City
of Yakima. Development has extended to the lower elevations of Naches Heights. The
slopes of the ground in the City of Yakima generally become steeper west of 16th Avenue.
3.2.2 Sewer Service in the Urban Service Boundary
The City of Yakima constructed a wastewater treatment facility in 1936 to provide for the
disposal of sewage generated within the corporate limits. In 1965, the City of Yakima
passed Resolution No. D-791, adopting a policy of providing City water and sewer
services to property outside the City limits.
In the early 1970's, the Washington Department of Ecology applied significant pressure
on Yakima County, the City of Yakima, the City of Union Gap, and the Terrace Heights
Sewer District to adopt a regional approach to sewer system development and related land
use planning issues. In response, an extensive study of alternative sewage systems was
conducted in the mid -70's by R.W. Beck & Associates. This study considered the
feasibility of sewer service to a number of areas, both inside and outside the City limits.
The Study concluded that having the City of Yakima provide regional sewer service,
utilizing a single centralized treatment plant, was the most cost effective and efficient
way to provide sewer service in the Yakima Metropolitan area.
On February 23, 1976, a "Four Party Agreement" was signed by the City of Yakima,
Yakima County, Terrace Heights Sewer District, and the City of Union Gap. Under the
agreement, an "Urban Service Boundary" was established adjacent to the City of
Yakima's boundaries. All parties agreed that: (1) within the Urban Service Boundary,
high density development with sewer service would be allowed and encouraged; (2) the
City of Yakima would be the regional provider of sewer treatment facilities; (3) sewer
service to individual property owners was to be provided by the City of Yakima, the City
of Union Gap, or the Terrace Heights Sewer District, and; (4) any property served by
sewers provided by the City of Yakima were required to annex or agree to annex in the
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DRAFT
future by signing an Outside Utility Agreement. It was further agreed that Yakima
County would not provide sewer service in the Urban Service Boundary "unless all other
entities involved have been unable or have refused to serve the area concerned on a basis
acceptable to the residents, and an impasse has been reached." In the event of such an
impasse, the entities were required to go through an administrative process to resolve the
disagreement.
The "Four Party Agreement" has remained in effect since 1976. The Agreement and the
1976 Study have been the central documents used by the City of Yakima for planning the
capacity and design of both the wastewater treatment plant and the sewer collection
system.
In late 1981, the Yakima Urban Area Comprehensive Plan was adopted by the City of
Union Gap, Yakima County, and the City of Yakima incorporating the goals and policies
of the "Four Party Agreement". The Yakima Urban Area Comprehensive Plan revised
the 1976 Urban Service Boundary as established by the provisional planning council, and
established the area to "be served by sewers in accordance with the aforementioned
Wastewater Facilities Planning Study (Volume 1)", and further stated "that the health and
welfare of the community require that all property within the urban boundary have sewers
available as soon as financially feasible and practical to do so." Figure 3-1 identifies both
the 1976 and 1982 Urban Service Boundaries.
Under the terms of the Agreement, the City of Yakima was mandated with the
responsibility to "provide wholesale users with sufficient treatment plant and interceptor
capacity to handle the design sewage flows in Table II -2 of the Yakima Wastewater
Facilities Planning Study (Beck Study)." Table 3-1 identifies these design sewage flows
as set forth in the Beck Study.
Table 3-11. Sewage Flows at Existing Wastewater Treatment Plants
Prior to Sewer Rehabilitation 1973. 1974
Treatment Facility Average Average Maximum Instantaneous
Annual Winter September Day Peak Flow
Flow (mg) Flow (mgd) Flow (mgd) Flow (mgd) (mgd)
Yakima Municipal 3,605 6.50 16.00 16.70 19.00
Yakima Industrial 180 0.00 1.80 2.60 3.80
Terrace Heights 49 0.21 0.31 0.35 0.54
Union Gap 192 0.42 0.70 0.72 0.96
Total 4,026 7.13 18.81 n.a. n.a.
Projected Sewage Flows at Existing Wastewater Treatment Plants
Subsequent to Sewer Rehabilitation
Yakima Municipal 2,580 6.50 10.30 12.04 14.95
Yakima Industrial 150 0.00 1.30 2.10 3.30
Terrace Heights 44 0.21 0.28 0.32 0.51
Union Gap 100 0.36 0.48 0.50 0.74
Total 2,874 7.07 12.36 n.a. n.a.
n.a. = Not Applicable
From R. W. Beck, 1976 Yakima Wastewater Facilities Planning Study, volume 1, Table 11-2
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 3
6 1 5
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HDR Engineering, Inc,
1111111
1111
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSRY
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Dote
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
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YAK MA FOUR PARTY
AND URBAN AREA
Figure Number
3-1
DRAFT
In 1988, a new Comprehensive Plan for the City's sewerage system was prepared by
HDR Engineering, Inc., and in 1989 the City's Facility Plan Update was prepared also by
HDR Engineering, Inc. These Plans provided the basis on which the City of Yakima
calculated the capacity of the treatment plant and undertook improvements. The capacity
and design of the treatment plant and the sewer collection system is based on several
critical factors, including: (1) The capacity of the treatment plant and the collection
system will provide service to all properties within the Urban Service Boundary but not
outside that area; (2) The collection system serving the Yakima Urban Service Area
would be operated and maintained by a single entity.
Improvements implemented by the City of Yakima since 1988 at the Yakima Regional
WWTP have increased the capacity of the treatment plant from those completed
following adoption of the "Four Party Agreement" in 1981 as follows:
Parameter
Beck Design
1987 Capacity
Rating
Current Capacity
Rating
Flow, mgd
Average Daily
13.3
13.7
--
Maximum Monthly AD
19.0
22.3
22.31
Maximum Daily
25.0
25.0
--
Peak
36.0
27.0
32.02
BOD, lbs/day
Average Daily
32,700
23,2004
--
Maximum Monthly AD
38,900
30,5004
34.5003
Maximum Daily
43,300
55.500
59.0003
TSS, lbs/day
Average Daily
22,700
35,000
--
Maximum Monthly AD
25,600
46,000
46,000
Maximum Daily
26.400
72,000
72,000
Ammonia — Nitrogen, lbs/day
Average Daily
--
1,3004
--
Maximum Monthly AD
--
1,8004
2,7003
Maximum Daily
--
2,6004
3,5003
I. Maximum Monthly AD must be tied to BOD, TSS, and NH4loadings
2. With 100 year flood in Yakima River
3. With MLSS at 2200 mg/ land trickling filter loading at 65 lb/kcf
4. With MLSS at 3000 mg/ land trickling filter at 65 lb/kcf
3.3 Current and Projected Population
Both the City of Yakima and Yakima County have experienced relatively stable
population growth since the 1960s, averaging approximately 1 percent per year. This
trend is expected to continue in the planning period. Population estimates are derived
from the Office of Financial Management (OFM) for Yakima County and allocated to
each City and its surrounding Urban Growth Area.
The projected population and number of new households required for the projections in
the areas currently served by the Yakima Wastewater Treatment Plant are summarized in
Table 3-2. The current population of 90,179 may understate the actual population since it
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PAGE 5
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includes the 1998 estimate for the Yakima Urban Service Area and 1996 estimates for the
Union Gap Urban Service Area and the Terrace Heights Urban Service Area.
Table 3-2. Yakima Wastewater Service and Planning Area Population
Projections
Area
Current
Population
Projected
Year 2015
Population
Projected
Year 2020
Population
Planned
Growth
To 2020
Household
Conversion
Factor
Total
Projected
New
Households
Yakima Urban Service Area
78,9871
100,0002
102,000
23,013
2.503
9,205
Union Gap Urban Service Area/Reserve
6.4774
7,9305
8,494
2,017
2.556
791
Terrace Heights Urban Service Area/Reserve
4,715'
7,3248
8,490
3,775
2.559
1.480
Subtotals
90,179
115,254
118,984
28,805
11,476
Yakima Urban Reserve
3,00010
13,81211
23,420
20,420
2.503
8,16811
Totals
93,179
129,066
142,404
49,225
19.644
1. 1998 Population Estimate from the 1998 Amendments Yakima Urban Area Comprehensive Plan, Adopted
November 24,1998.
2. 2015 High Population Estimate from the 1998 Amendments Yakima Urban Area Comprehensive Plan, Adopted
. November 24,1998, 21,013 assigned to existing Urban Service Area and 10,812 to Yakima Urban Reserve.
3. From the Yakima Urban Area Comprehensive Plan, adopted April 1997.
4. 1996 Population Estimate from the City of Union Gap General Sewer Plan, September 1999 (less than 50% not served).
5. 2015 Population Estimate from the City of Union Gap General Sewer Plan, September 1999.
6. From the City of Union Gap Comprehensive Plan, January 1999.
7. 1996 Population Estimate from the Terrace Heights Neighborhood Plan, Neighborhood Review Draft, December 1997.
8. Adjusted from 2016 population estimate from the Terrace Heights General Sewer Plan, March 1998 — high estimate is
14,145.
9. From the Terrace Heights General Sewer Plan, March 1998.
10. From the Yakima Urban Arca Comprehensive Plan, adopted April 1997.
11. Anticipated growth within the Yakima Urban Reserve accounted for in the Yakima Urban Service Area or Union Gap Urban
Service Area.
In accordance with the approved comprehensive plan for each jurisdiction, the projected
build -out population for all areas included in Table 3-2 is approximately 165,042. The
West Valley, Southwest, Terrace Heights, Union Gap and Southeast areas are expected to
accommodate the majority of this increase in population. Sewage flows from the City of
Moxee may be treated at the Yakima Regional WWTP in the future if their separate
treatment facilities become more costly than treatment at the Yakima Regional WWTP.
The Gleed area may also be served by the Yakima Regional WWTP by the year 2015.
3.4 Climate
Yakima lies in a semi -arid region. The Cascades to the west and the Rocky Mountains to
the east provide an effective shield from strong arctic winds, which results in generally
mild winters. The Yakima Urban Area experiences 300 days of sunshine annually. The
growing season in the area is about 190 days per year.
Precipitation averages approximately 8.3 inches annually. The summers are generally dry
with 1.5 inches of the average precipitation generally occurring between July 1 and
October 31. The area's precipitation during the months of November through February is
generally in the form of snow. The annual seasonal snowfall in Yakima is approximately
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24 inches. On the average, Yakima has at least 1 inch of snow on the ground 18 days per
year. The number of days which snow may remain on the ground varies greatly from year
to year. The prevailing winds in the area are from the west and northwest, with the
average strongest windspeed in the spring.
Table 3-3 shows average temperature and precipitation for Yakima between 1946 and
1999. In the winter months of December, January, and February, the average temperature
was 32 °F. The average monthly minimum temperature was 23 °F. The lowest
temperature, which occurred February 1, 1950, was -25 °F. In the summer months of
June, July, and August, the average temperature was 68 °F. The average monthly
maximum temperature was 85 °F. The highest temperature, which occurred on August
10, 1971, was 110 °F.
Table 3-3. Temperature and Precipitation
Month
Temperature Precipitation
Average Monthly Average Monthly Mean Average Total Average
Maximum °F Minimum °F Monthly °F (in.) SnowFall (in.)
January 37 20.1 28.6 1.26 8.2
February 45.7 25.6 35.7 0.77 3.3
March 55.3 30 42.6 0.69 1.4
April 63.8 34.9 49.3 0.52 0
May 72.8 42.4 57.6 0.54 0
June 79.7 49 64.4 0.71 0
July 87.4 53.1 70.3 0.19 0
August 86 51.7 68.8 0.32 0
September 77.7 44.3 61 0.37 0
October 64.2 34.9 49.5 0.57 0.1
November 48.1 27.9 38 1.06 2.8
December 38 22.5 30.2 1.32 8.5
Annual Average 63 36.4 49.7 -- --
Annual Total -- -- 8.32 24.3
1. Precipitation data from the Yakima WSO AP station number 459465 at the Yakima airport.
3.5 Soils
Soils in the lower elevations of the study area, along the Naches and Yakima Rivers, are
primarily of the Weirman-Naches-Ashere series. To the west of the Yakima River, the
soil classification changes to the Ritzville-Warden-Starbuck series and finally to the
Harwood-Gorst-Cowiche series. To the south of Yakima, and west of the City of Union
Gap along Wide Hollow Creek, the soils were identified as the Umapine-Esquatzel series.
A general description of the four major soil series in the Yakima Urban Area is as
follows:
D Weirman-Naches-Ashere: Very deep, well drained, nearly level to gently sloping
and generally located on floodplains and low terraces.
D Umapine-Esquatzel: Very deep, well drained to somewhat poorly drained, nearly
level to moderately steep and generally found on terraces and floodplains.
➢ Ritzville-Warden-Starbuck: Shallow to very deep, well drained, nearly level to
steep and typically located on uplands.
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> Harwood-Gorst-Cowiche: Shallow to moderately deep, well drained, nearly level
to steep and generally found on high dissected terraces.
The Weirman-Naches-Ashere soils, which underlie a significant portion of the City of
Yakima and the City of Union Gap, are characterized by a brown loam surface layer
about 9 to 10 inches thick. The subsoil is a gravelly loam and gravelly sandy clay loam
from 9 to about 20 inches thick. Below approximately 30 inches, the soil shifts to
gravelly sand.
The Umapine-Esquatzel soils are characterized by a brown silt loam surface layer about 7
to 17 inches thick. The underlying material, to a depth of 60 inches or more, is a brown
silt loam. In the Umapine group, soils are strongly alkaline and may be underlain by a
hardpan at a depth of 20 to 40 inches.
The Ritzville-Warden-Starbuck soils underlying the gently sloping area to the west of the
downtown area and the Terrace Heights communities are characterized by a surface layer
of grayish brown silt loam approximately 5 to 7 inches thick. The subsoil is a silt and/or
sandy loam to a depth of 60 inches or more.
The Harwood-Gorst-Cowiche soils are characterized by a loam surface layer about 7 to
10 inches thick. The underlying material to a depth of 60 inches or more is brown loamy
fine sand. A hardpan may exist under this series of soils at a depth of 12 to 30 inches. In
some areas, the soil is underlain by sandstone.
Most of the City's older sanitary sewers were constructed in the Weirman-Naches-Ashere
soil series. Although permeability is moderately slow through the loamy surface soil, the
subsoil is very permeable. In addition to the older sanitary sewers, the wood stave
irrigation pipes of the General Irrigation System, and a number of unlined irrigation
canals, were also constructed in this soil series. Leakage from the old wood stave pipes
and canals has long been considered a major source of infiltration/inflow into the sanitary
sewer system.
3.6 Subsurface Groundwaters
Subsurface water within the study area drains to the Naches and Yakima Rivers.
Ahtanum Ridge and the Rattlesnake Hills separate the upper from the lower Yakima
Valley. The Yakima River cuts through these east -tending ridges at Union Gap, which is
located south of the Yakima Urban Area and the City of Union Gap.
Union Gap is a rather narrow break in the ridge and movement of shallow subsurface
water in a southerly direction is constricted. Several areas of subsurface water are visible
in the southern portion of Yakima, and in the northern portion of the City of Union Gap.
Subsurface water has been recognized as a significant deterrent to development of
properties since the early 1900s. Portions of the storm drainage system in the Urban Area
actually serve as subsurface drainage systems. During construction of the sewage
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collection system in the City of Union Gap an underdrain pipe was installed in the same
trench and lower than the sanitary sewer from Ahtanum Road to Washington Street to
lower groundwater along its route from three to four feet below ground surface to a depth
of eight to ten feet. Groundwater levels beyond the influence of the underdrain remained
at three to four feet below ground surface. The City of Union Gap has experienced
various problems in the operation of the underdrains over the years, including broken
pipes and root intrusion. As the underdrains became surcharged due to these problems,
immediate increases in sewage system flows have been noted. Cleaning and rodding of
the underdrain until surcharging ceased resulted in a decrease of sewage system flows.
3.7 Storm Sewer/Subsurface Drainage
System
The City of Yakima has a separate storm sewer system. Many of the earlier storm sewers
in the downtown and surrounding residential areas were constructed as groundwater
drains rather than surface water drains, These older storm sewers were constructed of
concrete and vitrified clay and are more than 90 years old. Since storm sewers served as
groundwater drains, they were initially constructed with open joints. There is limited
information available on early storm sewer/subsurface drainage systems in the Yakima
Urban Area.
The storm sewer/subsurface drainage system has an important interrelationship with the
sanitary sewer system. Irrigation canals are the discharge points for many of the
underground storm sewer pipeline systems. Canals and storm sewers/subsurface drains
are used by industries for discharge of uncontaminated cooling water.
Many of the storm sewers/subsurface drains flow throughout the year and the flow
consists of a mixture of groundwater, irrigation water, industrial cooling water, and storm
runoff. Due to the close proximity of many of the storm sewers/subsurface drains to the
older sanitary sewage collection system, they are suspected of contributing to I/I to the
sewer system.
3.8 Existing Water Supply System
The City of Yakima's water supply is from the Naches River. Water is treated prior to
delivery at the water treatment plant. Figure 3-2 identifies the City of Yakima existing
water supply system. The City has four high production deep groundwater wells to back
up its gravity surface supply system. Three water purveyors supply water to areas
adjacent to Yakima's water service area:
➢ Nob Hill Water Association
➢ City of Union Gap
➢ Yakima County (Terrace Heights Area)
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 9
5
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CRY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
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WASTEWATER
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A. K RUT SCH
Oesigned
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Project Number
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Date
FEBRUARY 2000
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3-2
DRAFT
Five categories of domestic water use have been defined for the City of Yakima:
1) residential, 2) commercial, 3) industrial, 4) governmental, and 5) City (all
departments). A separate category of water use is irrigation water delivered to sections of
the City through separate distribution systems. The five primary categories have been
combined into the following three service classes.
Residential
The residential customer class includes both single-family and multi -family. This class
used 57 percent of the total metered water consumption in 1995. Inadequate pressure and
unreliable flows have led people to discontinue use of the separate irrigation system and
switch to the potable system for their irrigation system needs. This gradual conversion
from the irrigation system to the potable system has increased the residential flow usage.
Commercial and Industrial
The commercial and industrial customer classes used approximately 33 percent of the
water produced in 1995. Commercial users were considered to be shopping centers,
banks, office complexes, motels, and other businesses. The commercial monthly demand
was generally uniform throughout the year. Industrial customers were considered to be
primarily the fruit and vegetable processing industries, with summer use representing
twice the monthly average.
Governmental and City (all departments)
The governmental and City departments, including schools, used approximately 10
percent of the water produced in 1995. The governmental group includes the state,
federal, and county facilities.
The existing per capita water use, including all user classes and based on a total
population served by the City's water system of 47,000 in 1995, is given as follows:
Y Average Day Demand (ADD) - 268 gpcd (1999 — 14.0 mgd)
> Maximum Day Demand (MDD) - 423 gpcd (1999 — 21.3 mgd)
3.9 Existing Irrigation Supply
Portions of the City of Yakima are served by irrigation systems operated by the City as
shown in Figure 3-3. Each irrigation system is either served from an irrigation canal or
buried pipeline. The separate irrigation systems serve approximately 2,100 acres of
developed land and 11,000 customers.
The irrigation canals are suspected to be a large contributor to the increase in groundwater
depth during summer months. The canals, with the exception of the Fruitvale Canal, are
owned privately or by irrigation districts. The City is unable to exercise much control on
the operations and/or maintenance of these canals.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 11
0
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7.
100 PROJECT
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YAKIMA
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YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Orawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Cote
FEBRUARY 2000
I 1
THIS LINE IS ONE INCH WHEN
DRAWING 5 FULL SIZE IF NOT
ONE INCH. SCALE ACCOROINGLY.
EXISTING
IRRIGATION
SYSTEM
Figure Number
3-3
DRAFT
The majority of the irrigation systems operated by the City of Yakima consist of pipe
networks varying in size, construction and condition. The older systems are constructed
of wood stave pipe and are leaking.
City operated irrigation systems have approximately 150 blow -off valves located in sewer
manholes in the area east of the railroad tracks and approximately 250 of these valves in
the area to the west of the railroad tracks. The valves are generally 1'/2 to 3 inches in
diameter and have been flushed each spring and once every three or four weeks to clean
out deposits in the irrigation lines. An average of 6 to 7 valves are flushed daily during
the summer although, on occasion, as many as 25 valves are flushed in a day. The valves
are flushed for approximately 5 minutes at a flowrate ranging from 50 to 100 gallons per
minute. This totals approximately 10,000 gallons per day discharged into the sewer
system, which is insignificant compared to normal sewage flows. At times, the valves
have been stuck open. An open valve may discharge as much as 150,000 gallons per day
to the sewer system which, when added to other flows, may be sufficient to cause
surcharging in some sewer lines. The wastewater utility is currently working with the
water utility to prevent continuous discharge from the blow -off valves.
3.10 Sewage Flows
Sewage flow to the Yakima Regional WWTP is a combination of flow components
including domestic, commercial, institutional, industrial, and infiltration and inflow (I/I).
3.10.1 Domestic Sewage Flow
Domestic sewage flow is discharged from residences. If the sewer system was watertight,
the domestic flow in the Yakima collection system would be the largest component of the
total flow at the wastewater treatment plant. Domestic flow is generally expressed in
gallons per capita day (gpcd). For planning purposes, a domestic flow of 80 gpcd was
used in this plan based on historical comparison of domestic water use and domestic
wastewater flow for the City of Yakima.
3.10.2 Commercial Sewage Flow
Commercial wastewater characteristics are residential in nature though not always in
strength. Commercial flows are generally expressed in gallons per acre day (gpad).
Examples of commercial land use are office buildings, restaurants, laundries, grocery
stores, retail stores, shopping centers, etc. Flows from commercial facilities vary
considerably depending on region, climate, and type of facility. Commercial unit flow
rates shown in Table 3-4 ranged from less than 1,500 gpad to a high of 8,000 gpad.
HDR ENGINEERING, INC.
Cm' OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 13
DRAFT
Table 3-4. City of Yakima
Establishment
Office Buildings
Small Businesses
Hotels, Motels
Single story
Per story addition
Retail Commercial
Shopping Centers
Car Wash (24 cars/hr)
Laundry (per 10 washers)
Restaurants (per 200 customers)
Apartments (2 -story)
Commercial Flowrates1
Average Daily Flow (gpad)
2,000
1,500
3,000
2,000
2,000
2,500
8.000
5,000
2,500
3,500
Adapted from Metcalf & Eddy
Design for commercial areas should be conservative since there are large unit flow
variations. For unidentified land use that is zoned commercial, 1,000 gpad per gross
acreage is recommended for planning sewage service.
3.10.3 Institutional Sewage Flow
Institutional wastewater flows are essentially domestic in nature. Typical institutional
facilities include hospitals, schools, rest homes, and community colleges. Flow rates for
institutional facilities, shown in Table 3-5 are often expressed in terms of the number of
persons attending and/or residing at the institution (gpd/person, gpd/bed, gpd/student,
ect.). For land use zoned institutional, 2,000 gpad per gross acreage is recommended for
planning sewage service.
Table 3-5. City of Yakima Institutional Flowrates1
Establishment
Average Daily Flow
(unit/day)
Grade Schools
Middle Schools
High Schools
Community College
Hospital
Other Institutions
15 galUstudent
20 galUstudent
25 galUstudent
30 gall/student
300 gall/bed
200 gall/bed
I Adapted from Metcalf & Eddy
3.10.4 Industrial Sewage Flow
A portion of the City of Yakima's sewage collection system is affected by the discharge
of industrial wastes. Industrial flow may vary from little more than the normal domestic
rate per acre (800 to 900 gpad) to several thousand gallons per acre per day. The type of
industry to be served, the size of the facility, the method of pretreatment, the reuse of
water, and the discharge of cooling water to storm sewers will influence wastewater
quantities. A design allowance for estimating the flows from industrial districts that have
no wet -process industries is 2,000 gpad per gross acreage. Table 3-6 provides flows that
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 14
DRAFT
may be used when the nature of the industry and the anticipated capacity of the industry
are known.
Table 3-6. City of Yakima Industrial Flowrates1
Establishment Average Daily Flow
(gall/ton)
Cannery
Peaches and pears 4,500
Apples 2,000
Other fruits 3,500 — 8.000
Vegetables 12,000 — 16,000
Chemical
Ammonia 25,000
Sulfur 2,500
Food and Beverage
Beer 3,500
Meat packing 5,000
Milk products 5,000
Pulp and paper
Pulp 150,000
Paper 35,000
Adapted from Metcalf & Eddy
Industrial wastes can be highly variable in both quantity and quality depending on the
product produced. Treatment of industrial waste in domestic wastewater treatment
facilities burdens operating efficiency and increases operating costs. The City of Yakima
requires that industrial customers monitor their waste discharges. A strong waste
surcharge allows the City to recover the additional treatment costs from the industry
served for BOD and TSS.
Some industrial wastes contain toxic metals, chemicals, organic materials, biological
contaminants, and radioactive materials that are not compatible with the biological
processes used. The City of Yakima's sewer ordinance requires that incompatible wastes
be pretreated by the industry generating such a waste prior to their discharge to the
Yakima Regional WWTP. The Environmental Protection Agency (EPA) and
Washington Department of Ecology (WDOE) have proposed more stringent monitoring
of industrial waste discharges with new regulations designed to increase the pretreatment
requirements of certain industrial wastes.
Several industries, including Boise Cascade and Crystal Linen in northeastern Yakima;
Pepsi-Cola and Longview Fibre in southeastern Yakima; Michelsen Packaging near
downtown Yakima; and several storage and packing businesses in western Yakima, are
directly connected to the domestic sewerage system. The Weyerhaeuser Corporation in
the City of Union Gap is connected to the Union Gap collection system which discharges
to the Yakima Regional WWTP.
In locating future industrial facilities in Yakima, the following factors should be
considered:
➢ Separate employee waste from processing waters and discharge the employee
wastes to the sanitary sewer system.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000 PAGE 15
DRAFT
➢ Separate cooling water from processing waste, encourage reuse or provide for
discharge to the storm drainage system.
➢ Require pretreatment of industrial waste with reuse or land application in areas
other than the City's food processing waste sprayfield.
➢ Require new industries to provide separate treatment and disposal of effluent
waters with the City accepting employee waste only.
➢ Require pretreatment of industrial wastewater with constant discharge utilizing
on-site detention facilities. Discharge at night could be accommodated in the
collection system with minimal impact.
3.10.5 Influent Wastewater Flows and Loads
Influent flows and loads between January 1994 and December 1999 were analyzed to
determine the average flows and Toads to the Yakima Regional WWTP. Flows from
1997 through 1999 were chosen for the analysis. Three critical time periods of each year
were chosen for a detailed analysis of wastewater treatment plant flows and loads: March,
August, and October/November. The data has a strong seasonal character due to the
industrial load in the fall, low flows in the winter, and high flows in August. Table 3-7
summarizes the average and maximum influent flows and loads for the Yakima Regional
WWTP.
Table 3-7, Yakima Regional WWTP influent Flows and Loads
Parameter Average Maximum' Peak Hour2
Flow, mgd 11.28 15.35 24
BOD, mg/1 207 297
TSS, mg/1 189 475
TKN, mg/1 16 30
NH4, mg/1 19 29
1. Maximum represents maximum day.
2. Peak hour flow is an estimate.
The 1997-1999 data was evaluated to determine if a trend in the data was evident. The
data appeared to be reasonably random, and an average of the data for the 3 years was
calculated to serve as the basis of analysis.
3.10.6 Wastewater Flow Comparison
Influent wastewater flows and loads from the 1988 Comprehensive Plan for Sewerage
System are compared to data recorded from 1997 through 1999 in Table 3-8. The
comparison between these two sets of data showed that the:
➢ The 1985 low flow and peak flow rates are greater than those from 1997 to 1999.
This is most likely due to the infiltration and inflow reduction programs
completed in the collection system in the last decade, and possibly the
rehabilitation of the influent metering in 1997.
➢ The 1985 biochemical oxygen demand (BOD) and total suspended solids are
greater than the 1997 to 1999 concentrations. The 1985 ammonia nitrogen
concentrations (NI -14) are less than the 1997 through 1999 concentrations. The
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000 PAGE 16
DRAFT
low flow BOD decreased from 357 to 260 mg/1 (27%), TSS decreased from 248
to 234 mg/1 (5.6%) and the NH4 increased from 15 to 19 mg/1 (27%). High flow
BOD decreased from 257 to 144 mg/1 (44%), TSS decreased from 175 to 140
mg/1 (20%) and NH4 increased from 10 to 12 mg/1 (20%).
y In the winter, low flow period, the Yakima Regional WWTP has reduced the
infiltration and inflow (111) into the collection system by approximately 2.5 mgd
(20%) and, in the summer high flow period, the treatment plant flows have been
reduced by about 6.1 mgd (30%).
Table 3-8. Comparison of Yakima Regional WWTP Influent Flows
Parameter 1985 Low Flow 1997-1999 Low Flow 1985 High Flow 1997-1999 High Flow
Period'' 3 Period Periodt'4 Period2.4
Flow, mgd 12.8 10.3 20.5
BOD, mg/1 357 260 257
BOD, lb/d 38,200 22,270 44,000
TSS, mg/1 248 234 175
TSS, lb/d 26,500 22,040 30,000
NH4, mg/1 15 19 10
NH4, lb/d 1,650 1,627 1,700
14.4
144
17,270
140
16,790
12
1,440
1. 1985 values were reported in the 1988 Yakima Comprehensive Plan.
2. 1997 through 1999 values were taken from Yakima Regional WWTP data.
3. The low flow period is the average of the data from October and November.
4. The high flow period is the average of the data from the month of August.
3.11 Current Land Use
The land use pattern within the Urban Area is characterized by a north -south strip of high
intensity commercial development from north of the City of Yakima downtown area to
south of the City of Union Gap. These commercial developments are generally located
on both sides of First Street and are adjacent to the Burlington Northern Santa Fe railroad
corridor. Residential land use types range from the older established residential
neighborhoods immediately to the east and west of the north -south commercial and
industrial strip, to the newer residential developments in West Valley and Terrace
Heights.
During the past 15 to 20 years, shopping centers have been developed in the Urban Area
including Wards Plaza, the Yakima Mall, and Valley Mall. Commercial development has
also been placed adjacent to major east -west routes including Nob Hill Boulevard, North
40th Avenue corridor, and Fruitvale Boulevard. Multi -family residential developments
have been constructed throughout the Yakima Urban Area.
The Yakima Urban Area represents a regional center for cultural, shopping, and business
needs, in addition to its attraction to industries in the processing and handling of farm
products and manufacturing of apparel, textiles and wood products. The City of Yakima
currently offers excellent medical and dental facilities and is the location of the Yakima
Valley Community College (a state community college).
HDR ENGINEERING, INC.
CITY OF YAK!MA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 17
DRAFT
The City of Yakima conducted an assessment of current land uses for the Yakima Service
Area, including Terrace Heights and the City of Union Gap. The purpose of this survey
was to determine the amount and location of vacant land and establish the current ratios
of land uses. This information was based on parcel records from the Yakima County
Assessors office and is summarized in Table 3-9. This assessment did not include current
land use in the Yakima Urban Reserve.
Table 3-9. 1991 Existing Land Use Survey'
Land Use City Percent of Unincorporated Percent of Combined Percent of
Acres Total Acres Total Acreage Total
Residential 3,551 46% 3,168 30% 6,719 37%
Single-family 3,015 39% 2,950 28% 5,965 33%
Two-family 177 2% 42 0% 219 1%
Multi -family 285 4% 66 1% 351 2%
Mobile home park 74 1% 110 1% 184 1%
Commercial 940 12% 569 5% 1,509 8%
Industrial 1,295 17% 429 4% 1,724 9%
Pubiidsemi-public 296 4% 99 1% 395 2%
Parks & recreation 275 4% 326 3% 601 3%
Total developed 6,357 83% 4,591 43% 10,948 60%
Vacant 1,344 17% 6,039 57% 7,383 40%
Total area 7,701 100% 10,630 100% 18,331 100%
1. From the Yakima Urban Area Comprehensive Plan, adopted April 1997. Does not include streets, rights of ways,
railroads, canals, rivers or lands annexed since 1991. Data did include Terrace Heights and Union Gap Service
Areas.
Based upon current land use standards, the ratios in Table 3-9 compare favorably with
average ratios for cities under 100,000 people. These average ratios include 41 percent of
the land in residential use, 10 percent commercial land use, 7 percent industrial land use,
and 31 percent in public land use.
The Yakima Urban Area boundary differentiates the area of urban development from
those areas of agriculture, rural, and open space land use. Those properties located within
the Urban Area Boundary are considered to be dependent upon urban services such as
sewer and water services for development. The comprehensive plan and zoning maps
will control the future development of the Urban Area beyond the year 2000, depending
on future land use demands.
Studies performed by the City of Yakima planning staff indicate that the older residential
areas to the east and immediate west of the downtown area are generally occupied by
persons with incomes less than the Urban Area's mean family income. A substantial
number of residents in these areas are retired and living on fixed incomes. Over the past
20 years these older residential areas have gradually been shifting from owner -occupied
housing to rental housing. In several cases, older single family individual structures have
been removed and replaced with multi -family housing.
With the exception of some restoration and/or conversion of residential housing in the
older areas of Yakima, new residential construction has expanded into the West Valley
area and Terrace Heights (east of the Yakima River). The distribution of current land
uses in Terrace Heights, as reported in the 1998 Terrace Heights Neighborhood Plan, is
included in Table 3-10.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 18
DRAFT
Table 3-10. Terrace Heights Urban Growth Area Existing Land
Uses'
Existing Land Use
Designation
Vacant
SF Residential
Agricultural
Parks/Open Space
Commercial
Wholesale Trade/industry
Mining
Mobile Home Parks
Education Government
High Density Residential
Duplex/Fourplex
Federal
Totals
Number of
Parcels
385
1811
136
84
42
45
7
150
6
30
28
8
2732
Acres Percent
of Total
1418 32%
1125 25%
965 22%
458 10%
157 4%
133 3%
90 2%
85 2%
21 0%
10 0%
7 0%
3 0%n
4472 100%
1. From the Terrace Heights Neighborhood Plan, March 1998.
Table 3-11 summarizes the existing land uses for the Union Gap Urban Growth Area
(UGA), including an estimate of vacant developable land. Expansion into these areas has
resulted in a need for the extension of urban services, including sewer service, storm
sewers, water service, streets, and other governmental services. The adoption of the
Urban Area Comprehensive Plan by the City of Yakima, Yakima County, and the City of
Union Gap represents a concerted effort to coordinate future development.
Table 3-11. City of Union Gap Existing Land Use inventory'
LAND USE CATEGORY
Within 1995 Percent of City UGA Total Percent of Total
City Limits (acres) Acreage (acres) Acres Acreage
Vacant Land
(Vacant Developable Land)2
Agricultural
Residential
Industrial
Commercial
Public Facilities
Total Acres of Land
Including all Vacant Parcels
415
(311)
808
656
200
208
429
2.716
15%
(11.5%n)
30%
24%
7%
8%
16%
100%n
111
(66)
1606
325
27
526
(377)
2,414
981
227
208
429
2069 4,785
11%
(8%)
50%
21%
5%n
4%
9%
100%
Total Acres of Land
Including only Developable
Vacant Parcels
2,612 96%
2024 4,636
97%
1. From the City of Union Gap Comprehensive Plan, January 1999.
2. Vacant developable land includes a 25 percent reduction within the City limits and 40 percent for the UGA's.
This accounts for the land required for roads and utilities and land not suitable for development, such as sensitive
areas.
3.12 Drainage Basin Evaluation
Six major drainage basin boundaries were established for the Urban Area. These
drainage basins are listed in Table 3-12 and shown on Figure 3-4. The basin designations
are revised from the boundaries presented in previous reports to incorporate all area
within the City of Yakima Urban Growth Area. Figure 3-4 also shows those areas lying
outside the current Urban Growth Area and designated as Urban Reserve.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000 PAGE 19
6 1 5 1 4 1 3 1 2
1
SCALE
2500 0 2500 5000
LEGEND:
FEET
DRAINAGE BASINS
1982 URBAN SERVICE BOUNDARY
URBAN RESERVE
UNION GAP URBAN GROWTH AREA
URBAN
TERRACE HEIGHTS
SEWER DISTRICT
• BASIN B
YAKIMA
URBAN
RESERVE
BASIN E ,
TE1RRACE HEIGHTS
URBAN
RESERVE
UNION GAP
SERVICE
AREA
UNION CAP
URBAN RESERVE
HEIR Engineering, Inc.
CITY OF YAKIRA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project 4loneger
A. KRUTSCH
Designed
C. DOLSBY
Grown
E. MCDERMOTT
Checked
Project Number
06539-035-002
Da to
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
DRAWII G IS FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
0
a
00
co
0
z
YAK MA URBAN
AREA DRAINAGE
BASIN BOUNDARIES
Figure Number
3-4
DRAFT
Table 3-12. Drainage Basins
Basin Description
1986 Area 1999 Area 2025 Area
Served' Developed2 Developed2
A Downtown, Eastern area from railroad 1,373 acres 2,020 acres 2,108 acres
tracks to 11th Street.
B Downtown, Western area from railroad 2,276 acres 2,274 acres 3,830 acres
tracks including Carriage Hill, also
including Fruitvale. Generally north of
Lincoln Avenue.
C Includes memorial Hospital, Yakima 1,206 acres 1,103 acres 1,232 acres
Valley College and Nob Hill area.
Generally north of Nob Hill Blvd and
south of Lincoln. Western boundary is
generally considered as 34th Avenue.
D Includes Airport. Generally considered 988 acres 1,394 acres 1,993 acres
being the area between the Mead and
South Broadway.
E Includes areas between Nob Hill and 3,707 acres 2,602 acres 7,346 acres
Mead, as well as all properties West of
34th Avenue and Carriage Hill. Includes
unincorporated West Valley Area.
F East Yakima area between 11th Street 245 acres 455 acres 1,045 acres
and Yakima River. Southerly boundary
extends to Rudkin Road Pump Station.
Includes County fairgrounds and
Fairview -Sumac area.
1. From the 1988 Yakima Comprehensive Plan.
2. Developed areas were estimated from the City of Yakima's zoning
Each major basin for which the City of Yakima provides direct sewer service was broken
down into subbasins to be served by the City of Yakima to the year 2025. Approximately
200 subbasins were identified for performing a capacity analysis of the existing collection
system. The subbasins are shown in Figure 3-5.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 2i
2500
SCALE
0 2500
5000
LEGEND;
FEET
ORA'NAGE BASINS
UGSA
nisA
NOR Engineering. Inc.
CRY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACIU Y
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drown
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
I I
THIS LINE IS ONE INCH WHEN
DRAWING S FULL SIZE F NOT
ONE INCH. SCALE ACCORDINGLY.
z
YAK MA URBAN
AREA DRAINAGE
SUBBASIN
BOUNDARIES
Figura Number
3-5
DRAFT
3.13 Existing Sewer Service Area
The existing Urban Service Area Boundary consists of four political areas:
> The Yakima Urban Service Area, which includes City of Yakima boundaries and
the urbanized area west of the City within the Urban Growth Boundary.
> The Union Gap Urban Service Area, including the Union Gap City limits and
urbanized area located west of the City limits within the Urban Growth Boundary.
> The Terrace Heights Urban Service Area, which encompasses unincorporated
Yakima County, east of the Yakima River.
> The Urban Reserve; known as Zone 3 in the Yakima Urban Area Comprehensive
Plan, which includes a portion of unincorporated Yakima County, west of the
Yakima Urban Service Area; known as Urban Growth Area (UGA) 1, 4 and 6 in
the City of Union Gap General Sewer Plan, which includes a portion of
unincorporated Yakima County, west of the Union Gap Urban Service Area; and
known as an unincorporated area of Yakima County, south of the Terrace Heights
Urban Service Area.
3.13.1 Yakima Urban Service Area
The City of Yakima is presently the largest city in Central Washington State. It provides
shopping, institutional, medical, and cultural services to Central Washington.
The Yakima Urban Service Area, composed of 34 square miles, includes a variety of land
uses and residential densities. The most populated and intensely used commercial areas
are located within the City of Yakima. Urbanization beyond the City limits has occurred
primarily within the defined boundary for regional sewer service. This Urban Service
Boundary, established in 1976 and modified over the past 24 years, includes the City of
Yakima and the City of Union Gap, as well as 16 square miles of unincorporated land.
3.13.2 Union Gap Urban Service Area
The City of Union Gap is not within Yakima's Urban Service Area for planning purposes.
Union Gap's Urban Service Area is within the Urban Service Boundary of the Yakima
Regional WWTP.
The City of Union Gap is currently provided treatment service and some direct collection
system service under an interagency agreement with the Yakima Regional WWTP.
Union Gap has prepared a General Sewer Plan dated September 1999. Table 3-13 is
reproduced from the General Sewer Plan and identifies the anticipated population
estimates for the City of Union Gap through buildout of all lands within the Urban
Growth Area (UGA) and Urban Reserve Area of the City as shown in Figure 3-4.
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PAGE 23
DRAFT
Table 3-13. Union Gap UGA Population Estimates for the Planning Period
Area
1998
Population
2005
Population
2019
Population
Buildout
Population
Union Gap (1)
5.484
5,976
7,094
7,427
UGA 1 (1)
207
225
268
2.376
UGA 2
UGA 2 was annexed as the "South Broadway Area".
UGA 3
UGA 3 has been annexed by the City of Yakima
UGA 4 (I)
654 713 847 6,485
UGA 5
UGA 5 has been annexed by the City of Yakima
UGA 6 (2)
132
147
182
4,150 (3)
TOTAL
6,477
7,061
8,391
20,438
(1) Based on the Union Gap Comprehensive Plan population projections for County Low with GMA shift and growth
distributed throughout, the UGA. All populations increased from the 1990 population to each year's population at
the plans annual population rate increase of 1.23 percent.
(2) The 1998 population for UGA 6 was based on counting residence from a recent aerial photo and assuming 2.59
people per residence and then increasing the population by a 1.23 percent annual growth rate.
(3) The UGA 6 buildout population is estimated at 64 percent of the UGA 4 buildout population because the size of
UGA 6 land area is 64 percent of the size of UGA 4 land area. Both UGA areas have similar types of zoning.
(4) Refer to Union Gap Comprehensive Plan for identification of UGA boundaries.
Urban Growth Area 6 and the majority of Urban Growth Areas 1 and 4 lie within the City
of Union Gap Urban Reserve. Table 3-14 is also reproduced from the City of Union Gap
General Sewer Plan and identifies the design wastewater flows and characteristics for
Union Gap through buildout for both existing and future Urban Service Areas.
Table 3-14. Union Gap Summary of Wastewater Flow Design Criteria
(1) Assumes that All UGA areas contribute flow to the Master Lift Station
(2) Assumes a Peak Hour Peaking Factor of 2.9
(3) Assumes a Max. Month Peaking Factor of 1.17
(4) Does not incorporate an inflow allowance
(5) Maximum Concentration with Maximum Month Flow (BOD = 385 mg/I; TSS = 359 mg/1)
3.13.3 Terrace Heights Urban Service Area
Terrace Heights is within the greater Urban Service Boundary but constitutes its own
service area. Terrace Heights, while unincorporated, is served by the Terrace Heights
Sewer District, which currently is provided sewer treatment service from the Yakima
Regional WWTP through a interagency agreement. The City of Yakima supplies no
direct urban services to the unincorporated Terrace Heights Urban Service Area.
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PAGE 24
1998
2005
2019
Buildout
Peak Flow At Master
Lift Station (I) (2) (mgd)
1.37
1.51
2.73
10.17
Peak Flow At Rudkin
Road Lift Station (2) (mgd)
1.76
2.26
4.71
12.86
Max. Month Flow at
YRWWTP (3) (4) (mgd)
0.76
0.98
2.03
5.64
BOD Maximum Month
Lb/Day (5)
2,442
3,164
6,523
18,085
TSS Maximum Month
Lb/Day (5)
2,276
2,950
6,082
16,860
(1) Assumes that All UGA areas contribute flow to the Master Lift Station
(2) Assumes a Peak Hour Peaking Factor of 2.9
(3) Assumes a Max. Month Peaking Factor of 1.17
(4) Does not incorporate an inflow allowance
(5) Maximum Concentration with Maximum Month Flow (BOD = 385 mg/I; TSS = 359 mg/1)
3.13.3 Terrace Heights Urban Service Area
Terrace Heights is within the greater Urban Service Boundary but constitutes its own
service area. Terrace Heights, while unincorporated, is served by the Terrace Heights
Sewer District, which currently is provided sewer treatment service from the Yakima
Regional WWTP through a interagency agreement. The City of Yakima supplies no
direct urban services to the unincorporated Terrace Heights Urban Service Area.
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PAGE 24
DRAFT
Demand for services in the Terrace Heights Urban Service Area has historically been
localized in the center of the service area boundary. Currently, large developments are in
the planning stages to the north and east of the center of the service area. Development of
the Terrace Heights Urban Service Area boundary to the south and west of Terrace
Heights has been minimal. The Terrace Heights Sewer District has prepared a General
Sewer Plan dated March 1998. Table 3-15 is reproduced from the General Sewer Plan
and identifies anticipated population estimates, wastewater flow, and wastewater
characteristics for Terrace Heights through 2016. As noted in the Table, Terrace Heights
has projected growth rates of both 3 percent and 10 percent through 2016. The 10 percent
growth projection would represent approximate buildout conditions for all lands within
the Terrace Heights Urban Service Area.
Table 3-15. Terrace Heights Design Criteria
Design Criteria
1996(1)
2002
2016
3%
Growth
10%
Growth
3%
Growth
10%
Growth
Sewered Population (2)
4,715
5,564
7,544
7,544
14,145
Per Capita Domestic Flow (3)
52 gpcd
66 gpcd
66 gpcd
66 gpcd
66 gpcd
Average Domestic Flow (4)
171 gpm
255 gpm
346 gpm
346 gpm
648 gpm
Average Commercial
And Industrial Flow (gpd) (5)
30,000
53,600
66,300
66,300
108,500
Peaking Factor (6)
1.8-3.9
1.8-3.9
1.8-3.9
1.8-3.9
1.8.3.9
Peak Domestic, Commercial,
And Industrial Flow (gpm) (7)
555
847
1,137
1,137
2.098
Sewered Area (acres) (8)
1,300
1,570
1,570
2,200
2,200
Infiltration Rate (gpad)
133 (9)
300
300
300
300
Inflow Rate (gpad)
240 (10)
350
350
350
350
Infiltration and Inflow (gpm) (11)
337
709
709
993
993
Peak Hour Flow (gpm) (12)
892
1,556
1,846
2,130
3,091
Peak Day Flow (MGD) (13)
0.732
1.421
1.686
1.945
2.825
Maximum Monthly Flow (MGD) (14)
0.490
0.965
1.145
1.321
1.919
Peak Hour Flow (MGD) (15)
1.284
2.241
2.658
3.067
4.451
BOD Maximum Day (Ib/day) (16)
1,032
1.217
1,697
1,697
3,096
BOD Maximum Month (lb/day) (17)
670
791
1,072
1,072
2.010
SS Maximum Day (Ib/day) (16)
887
1,047
1,459
1,459
2,661
SS Maximum Month (Ib/day) (17)
704
829
1,155
1,155
2,107
(1) 1996 data based on totalized flow meter from Lift Station No. 1.
(2) Sewered Population taken from Table 2-6.
(3) The residential wastewater contribution on December 31, 1996 was Tess than the average annual per capita flow.
(4) Average Domestic Flow = (Per Capita Domestic Flow) x (Sewered Population) / 1440 gpm/gpd.
(5) The average commercial and industrial flow is based on increases proportional to the sewered population.
(6) Peaking factors in the system range from 2.2 to 3.9 depending on truck sewer pipe. Peaking factors at Lift Station
No. 1 ranged from 1.8 to 2.9 over the last six years. A peaking factor of 2.9 is used in this Plan.
(7) Peak flow as measured at Lift Station No. 1 from domestic, commercial, and industrial sources, based on a
peaking factor of 2.9, the highest peaking factor recorded in the last six years at Lift Station No. I.
(8) Sewered areas were determined using digital drafting techniques for planned areas of growth.
(9) Based on 1996 Average Summer Flow infiltration from diurnal curves.
(10) Based on December 31, 1996 — January 1, 1997 peak storm event.
(11) Infiltration and Inflow (gpm) = (Inflow in gpad + Infiltration in gpad) x (Sewered Arca in acres) / (1,440).
(12) Peak Hour Flow = (Peak Domestic, Commercial, and Industrial Flow) + (Infiltration and Inflow).
(13) Peak Day Flow = [(Pop.) x(Per Capita Flow) + (Com.)] x (1.84) + [(1/1) x (Sewered Area) x (1.84) / (2.9)].
(14) Max Month Flow = [(Pop.) x (Per Capita Flow) + (Com.)] x (1.25) + (U1)x (Sewered Area) x (1.25) / (2.9).
(15) Peak Hour Flow (MGD) = (Peak Hour Flow in gpm) x (1,440) / (1,000,000).
(16) Based on a weighted average of the 1996 peak day BOD and SS and projected population.
(17) Based on a weighted average of the 1996 maximum monthly BOD and SS and projected population
(BOD = 164 mg/I; TSS = 172 mg/I)
HDR ENGINEERING, 1NC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 25
DRAFT
3.13.4 Yakima Urban Reserve
The Yakima Urban Reserve is not currently within the Urban Service Boundary. Land
use planning will address this area so that the area can be included for future urban level
development. Capital facility planning must be conducted to ensure urban services are
available to the Yakima Urban Reserve. This plan looks at providing sewer service to the
Yakima Urban Reserve as shown in Figure 3-6. Yakima County, the City of Yakima, the
City of Union Gap, and area residents will conduct land use planning within the West
Valley Urban Reserve, Union Gap Urban Reserve, and the Terrace Heights Urban
Reserve in the future.
3.14 Future Land Use
Future land use designations indicate the preferred use of land areas within a particular
region. Future land use designations are generalized where development is expected to
occur. The future land use projections act as a guide to evaluate development proposals
for consistency with the Plan, along with applicable goals and policies. The Yakima
Urban Area Comprehensive Plan will be the basis for future land use decisions.
Table 3-16 summarizes the total acreage for the Yakima Service Area, utilizing the land
use designations contained in the Yakima Urban Area Comprehensive Plan. This future
land use table includes vacant parcels, and makes an adjustment to exclude public uses
such as parks, schools, and cemeteries from the vacant land totals. This 1998 Table,
which is based on City of Yakima GIS and the County Assessor database, indicates that
there are 5,587 total vacant acres or 4,934 non-public vacant acres in the Yakima Urban
Service Area. The vacant residential acreage currently in the existing Yakima Service
Area is adequate to serve a population increase of approximately 27,500 people.
Table 3-16. Summary of Future Land Use for the Yakima Service Areal
Future Land Use Categories
Total Public Use Total Vacant Total
Acres or Parks Vacant Public Parks Non -Public
(acres) Acres (acres) Vacant Acres
Low Density Residential 8,132 745 2,447 275 2,172
Medium Density Residential 2,526 555 291 0 291
High Density Residential 1,185 48 218 0 218
Professional Office 452 32 182 0 182
Neighborhood Cornmercial 570 0 104 0 104
Large Convenience Center 122 145 14 0 14
Arterial Commercial 1.504 57 370 0 370
Central Business District 863 138 17 0 17
Industrial 3,997 0 1,944 378 1,566
Totals 19,351 1,720 5,587 653 4,934
1. From the Yakima Urban Area Comprehensive Plan 1998 amendments, adopted November 24, 1998.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 26
THIS UNE IS ONE INCH WHEN
DRAWING $ FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
HOR Engineering, Inc.
SCALE
1500 0 1500 3000
FEET
SCALE
LEGEND:
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COWICHE CANYON
WILEY CITY
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WEST WASHINGTON
WIDE HOLLOW
WEST AIRPORT
SOUTH AIRPORT
URBAN SERVICE AREA BOUNDARY
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CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
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FACILITIES
PLAN
Project Monoger
A. KRUTSCH
Designed
C. DOLSBY
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E. MCDERMOTT
Checked
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FEBRUARY 2000
CITY OF
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YAK MA URBAN
AREA SEWER
BASIN BOUNDARIES
Figure Number
3-6
DRAFT
Within the Yakima Urban Reserve future land use designations have not been
established. It is anticipated that these issues will be addressed through a neighborhood
planning process initiated by Yakima County. The total acreage in the Yakima Urban
Reserve, and an estimate of vacant land is contained in Table 3-17. The current land
available in the Yakima Urban Reserve Area is anticipated to serve a population of
approximately 35,000 people at buildout.
Table 3-17. Summary of the Land Use for the Yakima Urban
Reserve
Land Use Category
Total
Acres
Rights -of —Ways, Railways, Rivers, ect 2,500
Developed Parcels 1,000
Vacant Parcels 3,500
Total Area 7,000
1. From the Yakima Urban Area Comprehensive Plan, adopted April, 1997.
The potential number of dwelling units, based on an assessment of land designated for
residential use, is summarized in Table 3-18. This analysis, which includes an adjustment
for right-of-way and related uses, indicates that there is a potential for over 35,000 new
dwelling units within existing and reserved Urban Growth Areas representing an increase
of approximately 87,500 people. There are currently an estimated 36,200 dwelling units
within the existing and reserve Urban Growth Areas. The total population within the
existing and reserved Urban Growth Areas would be approximately 177,500 at build -out.
This projection is not adjusted for market factors or sensitive areas, nor does it include an
analysis of underdeveloped land or the potential for changes in land use. The projection
does indicate that there is sufficient vacant land to accommodate all the projected growth.
Where growth will occur, and whether there are adequate public facilities to support this
growth, are important planning issues. For instance, it has been estimated that the City of
Yakima has enough vacant land within the existing Urban Growth Boundary and existing
Urban Service Area to support 11,000 of the estimated 14,000 new households that would
be needed by the year 2015. In considering vacant lands within the existing Urban
Growth Boundary and existing Urban Service Areas for the City of Yakima, City of
Union Gap, and the Terrace Heights, there appears to be sufficient lands available to
support 17,000 to 18,000 new households. The remaining 17,000 to 18,000 households
required to support a build -out population of approximately 177,500 people would be
constructed in the Urban Reserve Areas for Yakima, Union Gap, and Terrace Heights.
The projected build -out population of 177,500 would exceed the current approved
comprehensive plan build -out population of 165,042 people for the City of Yakima, City
of Union Gap, and Yakima County. This difference may be attributed to more than one
agency including the same available lands within their build -out Urban Service Area, or
may be attributed to the addition of areas to each agency's Urban Service Area which is
currently outside the proposed existing and reserved Urban Growth Areas as included in
their Comprehensive Plans.
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PAGE 28
DRAFT
Table 3-18. Wastewater Service Area Boundary Summary of Potential New
Dwelling Units
Land Use Type
Total Net Density Potential New
Vacant Acres Vacant Acres Factor Dwelling Units
Yakima Urban Service Area
Low Density Residential 2,447 1,83512 4 7,340
Medium Density Residential 291 2181 8 1.744
High Density Residential 218 164' 12 1,968
Subtotals 2,956 2,217 11,052
Yakima Urban Reserve
Low Density Residential 6,000 3,5003 4 14,000
Subtotals 6,000 3,500 14,000
Union Gap Urban Growth
Area/Reserve
Low Density Residentials 3,921 1,8234 3 5,469
Subtotals 3,921 1,823 5,469
Terrace Heights Urban Growth
Area/Reserve
Low Density Residential6 1,418 1,064' 4 4,256
Medium Density Residential 92 69' 8 522
High Density Residential 10 8' 12 96
Subtotals 1,520 1,141 4,904
Totals 14,397 8,681 35,425
1. Reduced 25 percent for Rights -of -Way.
2. Adjusted to exclude 275 acres of land in public use.
3. Reduced 40 percent for Rights -of -Way, railways and rivers.
4. Includes reduction of 25 percent for land in City limits and 40 percent outside of the City limits. From the City of
Union Gap Comprehensive Plan, January 1999.
5. The average density of residential development in Union Gap is three dwelling units per acre. From the City of
Union Gap Comprehensive Plan, January 1999.
6. All vacant residential land except multi -family would be developed at an average density of four units per acre.
The unincorporated and unsewered areas within the Sewer Service Area, and within the
Urban Reserves, are unsuitable for high density installation and operation of septic tank
drainfield systems as has been reported for the past 30 years. Hydraulic continuity with
the groundwater in the soils of the area is high, and physical filtration of pollutants is
considered to be low. In the 1970's, the City of Yakima received a grant from the
Environmental Protection Agency to extend interceptors and trunk sewers to unsewered
areas where drainfield disposal from septic tanks represented a high risk to pollution of
groundwater.
Septic tank and drainfield construction in unincorporated areas are approved by the
Yakima County Planning Department, Yakima County Health District, and WDOE. The
City of Yakima does not require mandatory connection of new construction occurring
outside of the City limits to the wastewater sewerage system. Although Yakima County
has approved development plats with covenants that require the subdivision/development
to connect to the sewer system when sewer service is "available", an accurate data base of
where these conditional approvals have been made is unavailable, and neither Yakima
County, Yakima County Health District, or WDOE appear to be enforcing the
requirement to connect the sewer system once the sewer system is "available". It is
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estimated that as many as 5,000 dwelling units are located within the Sewer Service Area
that have not been connected to the sewerage facilities.
3.15 Future Sewer Service Areas
3.15.1 GMA Planning
The Growth Management Act states that "urban growth should be located first in areas
already characterized by urban growth that have adequate existing public facility and
service capacity to serve such development [city limits — Zone 1], second in areas already
characterized by urban growth that will be served adequately by a combination of both
existing public facilities and services and any additional needed public facilities and
services that are provided by either public or private sources [urban service area outside
of city limits — Zone 2], and third in the remaining portions of the urban growth areas
[urban reserve (unincorporated urban growth area outside of urban service area) —
Zone 3]."
The City of Yakima Urban Area Comprehensive Plan states that "the Urban Reserve has
been added to the Yakima Urban Service Area to accommodate future development as
services become available". This area is not a service area at this time. Land use
planning will address this area so that the area will not be precluded from urban level
development in the future. Since this Urban Reserve is included within the 20 -year
comprehensive plan for Yakima, capital facility planning for this area will occur within
the 6-20 year time frame. Once the subarea land use plan is complete, the Yakima Urban
Area could be modified to include the West Valley Urban Reserve area so that land use
planning and capital facility planning would be consistent.
The capital facilities element must include a forecast of future needs for capital facilities,
and the proposed locations and capacities of expanded or new capital facilities, and at
least a six-year plan that will finance such capital facilities. The land use element, the
capital facilities element, and the financing plan within the capital facilities element must
be coordinated and consistent (RCW 36.70A.070). The need for capital facilities should
be dictated by the phasing schedule set forth in the land use element (WAC 365-195-
315(2)(e)). In the case of Yakima, this directive means that capital facilities planning
should be in accordance with Zones 1, 2 and 3 development.
The Growth Management Act states that "in general, cities are the units of local
government most appropriate to provide urban governmental services." It has been
established by the Growth Management Hearings Board that sanitary sewer service is an
urban governmental service and that this service should be limited to areas of urban
growth. Any public services required in the Urban Reserve area would be financed by the
local -private resources.
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3.15.2 Yakima Urban Service Area
The Yakima Urban Service Area is expected to increase in population by the year 2015 to
approximately 100,000 persons. Based on the premise of GMA, the boundary of this
service area would not be expected to change, and has adequate growth capacity to
accommodate new residential construction to approximately 2025 at a build -out
population of 106,600.
3.15.3 Yakima Urban Reserve
The 9.3 square mile Yakima Urban Reserve area will provide phased future development
to the Yakima Urban Service Area. Identification of the area needed for future urban
development provides some certainty to the public and landowners regarding the future
land use of this area. Costs of infrastructure by local -private landowners can be
minimized and better understood through sound planning in advance of specific
development proposals. By 2015, the Yakima Urban Reserve is expected to have a
service area population of approximately 10,812 persons. The build -out population of the
Yakima Urban Reserve area is approximately 36,300 people and is not expected to be
reached until 2050 or beyond.
3.15.4 Union Gap Urban Service Area
The population of the City of Union Gap is projected to increase to approximately 7,930
persons from the present population of 6,477 by the year 2015. This is a low population
estimate from the 1999 City of Union Gap Comprehensive Plan. The boundary of the
Union Gap Urban Service Area is not expected to change before 2015 and is in the most
part the boundary specified by the 4PA agreement. The Comprehensive Plan and zoning
maps will help to control the future development of Union Gap Service Area through the
year 2015 and beyond. The build -out population for the City of Union Gap existing and
reserve Urban Growth Areas is approximately 20,438 persons and is not expected to be
reached until 2050 or beyond.
3.15.5 Terrace Heights Urban Service Area
Two boundaries will help to define the future service area. The Urban Growth Boundary,
set by Yakima County, identifies areas that may be served by utilities within 20 years.
The second boundary, the Four Party Agreement (4PA), defines the area that the Terrace
Heights Sewer District may serve as mutually agreed upon by Yakima County, the City of
Yakima, the City of Union Gap, and the Terrace Heights Sewer District. Residents
currently located outside the service area boundary, but inside the Four Party Agreement
boundary are currently served by septic or private systems, but can choose to be served by
Terrace Heights Sewer District. This connection is restricted in areas with low
population densities. The current service area boundary has been expanded to
accommodate all of the known developments that are scheduled for the next 20 years.
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The population of the Terrace Heights Sewer District is expected to increase from 4,715
to approximately 7,324 in 2015. The build -out population within the Terrace Heights
existing and reserve Urban Growth Area is approximately 14,145 persons and is not
expected to be reached until 2050 or beyond.
3.16 Streams, Creeks and Drainage Ways
The Yakima River, with a length of approximately 221 miles, is the largest river lying
entirely within the borders of the State of Washington. Its drainage area covers nearly
7,000 square miles and approximately half of the watershed lies above the Study Area.
The river has its origin in an unnamed lake in the Cascade Mountains, northwest of
Kechelus Lake. It travels across the Kittitas, Ahtanum, Moxee, and Yakima valleys to its
confluence with the Columbia River.
The Naches River drains approximately 25 percent of the Yakima Basin, is the Yakima
Rivers' largest tributary, and enters the Yakima River at the northern border of the Study
Area. Other tributaries to the Yakima River, located within the Study Area, include Wide
Hollow Creek, Bachelor Creek, Spring Creek, Cowiche Creek, and Ahtanum Creek.
Precipitation at the Yakima River headwaters occurs principally in the form of heavy
winter snowfall. Precipitation within the drainage basin varies from 30 inches annually at
higher altitudes to less than 10 inches at the lower elevations.
Since the primary source of runoff to the river is in the form of snowmelt, the highest
flows coincide with the onset of warmer weather in the spring. Minimum flows occur
during the fall season prior to winter rains. Table 3-19 presents mean monthly flows for
the Yakima River in the vicinity of the Yakima Urban Area.
Table 3-19. Average Monthly Flows for the Yakima River From 1967
to 19951
Month Average Yakima River Flow (cfs)
January 2956
February 3698
March 3942
April 4569
May 5845
June 5658
July 3720
August 3331
September 2688
October 1650
November 1847
December 2928
1. From streamflow data for station 12500450 in the Lower Yakima Basin. The station is located in the Yakima
River above Ahtanum Creek at Union Gap, WA.
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Flows in the Yakima and Naches rivers are controlled by six storage reservoirs operated
by the U.S. Bureau of Reclamation in the summer months. These reservoirs have a total
storage capacity of more than one million acre-feet. Normal operating procedure for
these reservoirs is to store excess spring runoff to augment natural flows during the
second half of the irrigation season, from June through September.
The water resources of the Naches and Yakima rivers are fully allocated to existing water
users. In late summer, flows to the Naches and Yakima rivers consist almost entirely of
storage releases. These releases frequently do not meet irrigation demands during drier
years, despite the storage capacity of the existing reservoirs.
3.17 Sensitive Areas
The most significant environmental constraints in the Yakima Wastewater Planning Area
are rivers and creeks, and their associated floodplains, flood ways, tributaries, and
wetlands. Figure 3-7 identifies the natural waterways and associated floodplains for the
area. The Yakima River, which forms the boundary between the Yakima Urban Service
Area, and the Terrace Heights Urban Service Area, is the largest sensitive area. In Union
Gap, sensitive areas include lands adjacent to Ahtanum, Bachelor, Spring, and Wide
Hollow Creeks.
Each of the four service areas have included proximity to sensitive areas into their land
use designations, and have emphasized compatible uses such as open space, parks, and
recreation. Each jurisdiction has adopted policies and procedures to assure that
development does not infringe on sensitive areas and their required buffers. As a result,
sensitive areas do not represent a significant limitation on future population growth.
The Growth Management Act (GMA) requires cities and counties to protect resource
lands and environmentally sensitive or critical areas within their comprehensive plans.
GMA requires classification, designation, and regulation of these areas. Sensitive areas
that require protection within the urban area are:
➢ Wetlands
➢ Aquifer Recharge Areas
➢ Frequently Flooded Areas
➢ Fish and Wildlife Habitat Conservation Areas
➢ Geologically Hazardous Areas
The GMA also requires cities and counties to protect natural resource lands of long-term
commercial significance including forest, agricultural, and mining resource lands. Both
gravel extraction and agricultural activities still take place on a limited basis within the
urban area, but are not considered to be of long-term commercial significance. The
following sections provide a summary of sensitive areas that require protection within the
urban area.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 33
D
C
A
5
4
3
1 — —
NACRES
RIVER
YAKIMA
RIVER
SCALE
2500 0 2500
FEET
LEGEND:
5000
FEMA 100 YEAR FLOGDPLA!N
CANALS, FIVERS ANO CREEKS
LAKE
ASPEN
WILLOW
LAKE
•
kok-
ttow
CRf
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
I I
THIS UNE IS ONE INCH WHEN
DRAWING S FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
0
a
•Cu
a
0
0
Z
NATURAL
WATERWAYS
IN THE YAKIMA
URBAN AREA
Figure ;lumbar
3-7
DRAFT
3.17.1 Wetlands
Wetlands are fragile and environmentally sensitive ecosystems, which serve a number of
important functions. The value and function of wetlands is to:
> Provide communities with open space.
> Control floods and reduce flood damages by slowing down and storing excess
waters during storms.
> Prevent erosion by reducing water velocities.
> Provide critical wildlife, plant, and fish habitats.
➢ Provide vital resting, feeding and breeding places for birds, especially migrating
ducks and geese.
> Maintain water quality by filtering pollutants out of the water prior to discharge to
streams and lakes.
> Serve as aquifer recharge areas, maintaining increased quantity and quality of
groundwater for residential, industrial and agricultural uses.
➢ Store surface water for release to streams and agricultural uses.
➢ Provide aesthetic and recreational opportunities such as fishing, hiking,
swimming, hunting, and birdwatching.
The Growth Management Act requires cities and counties to designate wetlands for
protection purposes. Wetlands as shown in Figure 3-8 are generally characterized by the
presence of water, hydric soils (soils saturated with water), and plants that are adapted to
live under these conditions. The Growth Management Act requires wetlands to meet all
three of these criteria.
A field study conducted in 1991 provided insight on the location and composition of the
wetland areas in the Yakima Urban Study Area. Fourteen sampling plots were
established in which detailed vegetative soil and hydric data was gathered and recorded
on field data sheets. The study findings included:
➢ Most of the study area contains upland vegetation, and wetlands are almost
exclusively located on riverline and palustrine corridors, or immediately adjacent
to irrigation ditches.
➢ Due to the utilization of extensive drainage ditch systems in the area, very few
areas were indicative of wetland hydrology. No surface water was observed at
any of the sampling plots other than those located within the banks of the Yakima
or Naches Rivers. The ditching system has effectively drained nearly all areas
mapped as containing hydric soils. Thus, hydric soil mapping is not an effective
means of predicting wetland occurrences within the urban area.
➢ Development in the vicinity of the Yakima or Naches rivers should be
discouraged.
➢ Wetlands within the urban area provide valuable functions including fish and
wildlife habitat, floodflow attenuation, toxicant removal, groundwater exchange,
recreational opportunities, and increased aesthetics for the study area.
HDI? ENGINEERING, INC.
CITY OF YAKIAMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 35
0
A
3
••• 4 ;I
_•
•
• ;
•• !- . •
• •
• :
o
2500
LEGEND:
SCALE
0 2500
FEET
•
WETLANDS
5000
HDR Engneering, Inc.
CRY OF YAKIMA
. • .
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
DRAWING S FULL S ZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
YAK MA URBAN
AREA WETLANDS
Figure Number
3-8
DRAFT
Further analysis conducted by the City's Geographic Information System indicated that
within the Urban Area, wetlands occupy less than 4 percent of the total land area. This
area is located along and within the Yakima and Naches Rivers. Wetlands account for
slightly over three percent of the land area within the City limits, mainly in the riverline
channels.
3.17.2 Aquifer Recharge Areas
The Growth Management Act requires protection of land and water to restrict
incompatible uses within "areas with a critical recharging effect on aquifers used for
potable water". The State Department of Community Trade and Economic Development
regulations state that at a minimum, aquifers that provide potable water must be protected
from contamination.
Precipitation infiltrates into the soil and percolates to the water table through soil or rocks
near the surface. This action recharges the groundwater system. Areas of permeable soils
and geology readily accept precipitation and are likely to be aquifer recharge areas and
affect the quality of the groundwater.
The basaltic hydrogeologic unit in the Yakima Urban Area contains the most productive
aquifer in the area. Much of the deep groundwater in the basalt is under artesian pressure.
Recharge to the aquifer takes place beyond the Yakima Urban Area, on the slopes and
upland benches of the Ahtanum Ridge and Cowiche Mountain. Generally, groundwater
in the basalt flows from the inlet areas at the higher elevations toward the Yakima River.
A shallow aquifer also exists within the urban area composed of the alluvial deposits,
which are principally unconsolidated gravel and sand. Most of the low flow domestic
wells in the area tap into the alluvium shallow aquifer.
The results of aquifer evaluations have determined that most of the Yakima Urban Area
has conditions favoring an increased susceptibility to contamination of the shallow
aquifer. The contaminant loading potential for shallow wells is especially high near the
industrial sections of the Urban Area. Some contamination has been documented in the
shallow wells within the City of Yakima, and hazardous waste contamination of the
shallow aquifer has occurred along the First Avenue railroad industrial area. Residential
areas utilizing septic systems have a high potential to contaminate the shallow aquifers.
The shallow aquifer is influenced by local irrigation practices, and is at it's maximum
height in August and at it's minimum in March.
The deeper aquifers, including wells deeper than 400 feet, do not appear to be as
susceptible to contamination as the shallow aquifers. Protection of the deeper aquifers
may be attributed to recharge of the aquifer from outside the urbanizing area, potential
intermediate layers of clays which prevent downward percolation of groundwater from
the shallow aquifers, and/or upwelling recharge of the aquifer from underlying
formations.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 37
DRAFT
The following steps will help to reduce future groundwater contamination.
• Avoid septic tanks and drainfields in the Yakima Urban Area.
Y Implement education and public awareness programs concerning water quality
issues.
D Continue programs for the collection and disposal of hazardous waste.
D Implement a monitoring program for industries in the urban area.
3.17.3 Frequently Flooded Areas
Frequently flooded areas are lands in the floodplain subject to a one percent or greater
chance of flooding in any given year. These areas include streams, rivers, lakes and
wetlands. Classification of frequently flooded areas reflect the 100 -year floodplain
designation of the Federal Emergency Management Agency (FEMA) National Flood
Insurance Maps.
According to the Growth Management Act, when designating and classifying frequently
flooded areas, the following items shall be taken into consideration:
D. Effects of flooding on human health, safety and public facilities and services.
D Available documentation including federal, state, and local laws, regulations,
programs, local studies, maps, and federal flood insurance programs.
D The future flow floodplain, defined as the channel of the stream and that portion
of the adjoining floodplain that is necessary to contain and discharge the base
flood flow at buildout without a significant increase in flood heights.
D Greater surface runoff caused by impervious surfaces.
In the Upper Yakima Valley area, the mapped floodplains of the river and stream
corridors currently shown on the FEMA maps include many critical areas protected under
the Growth Management Act. Therefore, the existing floodplain actually serves a much
broader purpose of protecting these critical areas through existing design controls.
3.17.4 Fish and Wildlife Habitat Conservation Areas
The Growth Management Act requires cities and counties to designate fish and wildlife
habitat conservation areas in order to review development proposals that may be
incompatible with these areas. The Washington State Department of Community, Trade
and Economic Development's Minimum Guidelines that are applicable to Yakima define
the following areas as fish and wildlife habitat conservation areas:
D Areas where endangered, threatened, and sensitive species have a primary
association.
D Habitats and species of local importance.
D Naturally occurring ponds under 20 acres and their submerged aquatic beds that
provide fish or wildlife habitat.
D Waters of the State of Washington.
HDR ENGINEERING, INC.
CITY OF YAKId1A
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 38
DRAFT
The guidelines recommend that local governments focus protection efforts on primary
habitat areas, and that cities and counties should consider identifying any federal and
private conservation areas within their jurisdictions, and the potential impact that
development might have on these areas.
A Priority Habitats and Wildlife Species Survey performed by the State of Washington
Department of Wildlife in 1991 identified critical areas that are considered sensitive
locations due to an endangered or threatened wildlife species presence. The upper valley
of Yakima contained several of these species in different habitat areas. The majority of
the habitat areas in the upper valley lie within the previously identified FNMA floodplain
boundaries, which include other environmentally sensitive areas such as wetlands.
Wildlife Habitat Areas are shown in Figure 3-9.
3.17.5 Geologic Hazards and Risks
Geologic hazards in areas such as steep slopes and unstable soils, identified in the
Yakima Urban Area Comprehensive Plan, include areas susceptible to erosion, sliding,
earthquakes, or other geologic events. These areas can pose a threat to the health and
safety of citizens when incompatible commercial, residential, or industrial development is
sited in areas of significant hazards. Some geologic hazards can be reduced or mitigated
by engineering, design, or modified construction practices so that risks to health and
safety are acceptable. When technology cannot reduce the risks to acceptable levels,
construction in geologically hazardous areas should be avoided.
HDR ENGINEERING, INC.
CITY OF YAKMIA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE39
b
L
5
I
3
SCALE
5000 0 5000 10000
FEET
LEGEND:
HABITAT AREAS
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
1— I
THIS LINE IS ONE INCH WHEN
DRAW C IS FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
v
v
0
o'
m
O
Z
YAK MA URBAN
AREA WILDLIFE
HABITAT AREAS
Figure Number
3-9
DRAFT
3.18 Flora and Fauna
The vegetation of the study area is made up of a mosaic of natural and cultivated plant
communities. The natural community consists primarily of native species that are the
remains of the original vegetation, or those which have established themselves, without
the assistance of man, on disturbed sites. Cultivated communities are those which result
from the more or less continuous activity of man and are typified by, but not limited to,
lawns, gardens, landscaped areas, and cultivated fields.
Natural vegetation in the area consists of the water -loving shrubs, trees, and plants
adjacent to the surface water to the desert community plants on the hills and ridges. Near
the Yakima and Naches River, aspen and alder trees are common, while sagebrush and
desert grasses dominate the undeveloped areas.
The wildlife in populated portions of Yakima Urban Area consists of primarily of those
species commonplace to residential communities, including songbirds, squirrel, and
chipmunks. The Yakima and Naches River corridor supports a variety of wildlife
including eagles, hawks, and beavers. Game birds are also prevalent in the area,
including ducks, pheasant, and quail. In the less populated areas, deer, skunk, and coyote
may be found.
3.19 Environmental Conditions/Limitations
This section is intended to summarizes environmental issues that relate to the Yakima
Comprehensive Plan. The summary emphasizes, from an environmental perspective,
major conclusions, significant areas of controversy and uncertainty, if any, and the issues
to be resolved, including the environmental choices to be made and the effectiveness of
mitigation measures. It also focuses on any significant irreversible or irretrievable
commitment of natural resources that would be likely to harm long term environmental
integrity.
The construction of proposed interceptor sewers included in this plan would result in both
positive and negative impacts on the environment of the area. These can be classified as
either primary or secondary impacts. Primary impacts are those which are caused directly
by a proposed action. They include many short term effects during construction as well
as longer term impacts such as payment for the cost of the facilities and improvement of
water quality. Secondary impacts will result from the response of man and nature to the
development of the proposed collection facilities. These impacts could include changes
in land use or population distribution resulting from the construction of the proposed
facilities. The secondary impacts may be short term, although in the case of proposed
collection facilities construction, they tend to be long term and have a greater overall
effect than the primary impact. Secondary and higher order impacts are less certain to
occur than primary ones due to the number of possible responses to a given action.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 41
DRAFT
3.19.1 Primary Impacts
The following describes the major impacts to the physical and human environments that
are expected to result directly from the construction and operation of the facilities
proposed in this Wastewater Facilities Plan.
3.19.1.1 Physical Environment
Water
Implementation of this Plan will make sewer service available to built-up areas on the
fringes of the City of Yakima that are presently served by septic tanks. This will improve
both surface and groundwater quality. The major improvements in water quality will
consist of a marked reduction in the organic matter and bacteria in the wastewater to local
surface waters within the study area, and the elimination of the discharge of wastes
including organic matter, bacteria, and viral pollutants to the local groundwater. The
benefits described above are both long term and cumulative on their impact in the study
area.
Earth
The construction of the proposed sewer interceptors will result in local disruption of the
environment. Most of the construction of the interceptors will occur along street right of
ways, although in a few instances, it will be necessary to route the interceptors across
private property, which may result in some local disturbance to farmlands in the West
Valley area. The latter is not expected to be severe and the disturbed area can revert to
agricultural uses following the installation of the pipeline. The construction of the sewer
interceptors would be accomplished with a minimal amount of noise and dust.
The short term adverse environmental impacts that can be expected during construction
will be mitigated by requiring contractors to follow good construction practices. The long
term impacts of the sewer interceptors will be negligible since the pipelines will be buried
and the surface restored to its original condition.
Air
It is not anticipated that the expanded collection facilities or expanded wastewater
treatment facilities will result in adverse air pollution, air emissions, or odor problems.
3.19.1.2 Human Environment
The construction activities will result in a certain amount of inconvenience to persons
living in the vicinity due to dust, noise and in some cases the need to detour around
construction activity. Most of the construction will be accomplished within existing
street right of ways but in some cases people will have the additional inconvenience of
having sidewalks and front lawns disturbed by the construction. Every effort will be
made to coordinate the construction activities and to provide timely information to
residents who may be inconvenienced by construction.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 42
DRAFT
The construction activity on the sewer interceptors will stimulate the Yakima area
economy by providing employment for construction workers for a few years. The study
area, including the Union Gap and Terrace Heights Service Areas and the Yakima Urban
Reserve, has a population of approximately 93,000 people and it is anticipated that
construction personnel would be drawn from the local labor force and that there will not
be any significant influx of population due to the construction. This could be influenced,
of course, by the amount of other construction activity in progress at the same time.
Both the employment and resulting economic benefits to the local economy will be short
term since the expanded and improved facilities can be operated with relatively few
personnel. It is not anticipated that the total wastewater system personnel will increase by
more than ten employees to service the expanded service area.
3.19.1.3 Energy
The implementation of this Plan may serve to decrease the overall system energy
requirements. Part of the sewer facilities program will consist of sealing the existing
sewer system. This program will reduce the extraneous flows to the collection system
pumping stations and the Yakima Regional WWTP during the peak summer period. This
reduction in extraneous flows entering the system will reduce pumping requirements.
3.19.2 Secondary Impacts
3.19.2.1 Physical Environment
The construction of the sewer interceptors can be expected to produce responses that will
in turn result in secondary impacts. The principal secondary impact will be in the form of
growth pressures in areas where sewer service is made available and where the lack of
this utility has retarded growth in recent years. It is not anticipated that there will be any
significant secondary impacts on the physical environment, so this discussion will center
on the impacts on the human environment. It should be noted that new growth in and of
itself can produce tertiary impacts such as air pollution, possible loss of farmland, and
increased demand for public facilities and services. This discussion addresses possible
tertiary impacts only in a cursory manner in the discussion of secondary impacts since this
higher order impact can be due to a variety of actions, making the cause -effect
relationship to the proposed action less clearly defined. In the Yakima area, tertiary
impacts will be largely determined by factors other than sewage disposal, although as
discussed below, the availability of sewage facilities can have a modifying effect on
growth and these impacts.
3.19.2.2 Human Environment
The growth of the Yakima Urban Area is dependent largely on socioeconomic factors
including the ability of the region to provide jobs for its youth and to attract new
population to the area. The proposed interceptor and wastewater treatment facilities will
allow growth to follow regional planning concepts and promote the orderly development
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000 PAGE 43
DRAFT
of the Yakima Urban Area. It is true that the new development will require streets,
utilities and other public facilities and services but these same facilities and services
would be required to accommodate the growth regardless of whether the wastewater
facilities were constructed. It is likely that the cost will be somewhat less if the Yakima
Urban Area Comprehensive Plan is implemented since it will promote orderly growth and
thereby concentrate the needs for these services and facilities.
3.19.3 Special Considerations
3.19.3.1 Unavoidable Adverse Impacts
The only unavoidable adverse environmental impacts associated with the development of
the proposed Wastewater Facilities Plan projects will be the disruption caused to the
natural and human environment during construction. Most of the completed system will
be entirely underground which minimizes any permanent effects on the environment.
3.19.3.2 Mitigation Measures
The proposed routes for sewer interceptors have been selected so as to minimize potential
adverse impacts. Provisions will be inserted in the construction plans and specifications
and construction supervision will be provided to further minimize potential adverse
environmental impacts by requiring the contractors to take precautionary measures and to
schedule his work so as to avoid critical environmental conditions. City of Yakima
personnel have been involved in the planning process and will assist in coordinating the
contractor's work. The above ground sewage facilities, including pumping stations and
the Yakima Regional WWTP, will be architecturally designed and landscaped so as to be
compatible with surrounding land uses.
3.19.3.3
Relationship Between the Local Short Term
Environmental Uses and the Maintenance and
Enhancement of Long Term Productivity
The Wastewater Facilities Plan will provide sewerage facilities and will help to facilitate
normal growth and development of the Yakima Urban Area and improve the public
health conditions for the residents by eliminating ground and surface water contamination
from septic tanks. The proposed facilities are coordinated with the local growth policies
and available land use information. They should assist in achieving both the short and
long range planning goals of the area. An important consideration is that the sewerage
facilities should encourage development in areas planned for urban uses and thereby
direct it away from preserved prime agricultural areas.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 44
SECTION 4
EXISTING & PROJECTED WASTEWATER CHARACTERISTICS
4.1 Introduction
Developing realistic flow and loading projections is critical to defining the facilities and
space required for near-term, year 2024, and ultimate buildout conditions. It is also
necessary for identifying phasing opportunities that balance reliable treatment capacity
with minimizing ratepayer impacts.
To plan for future wastewater facility needs, it is necessary to project the amount of
wastewater and loadings that will be received and treated. Wastewater quantity is
influenced by the population served, the magnitude of commercial activities, and the
quantity of extraneous flow, such as sewer system infiltration and inflow. To plan
treatment facilities, it is also necessary to identify wastewater characteristics, including
the organic and suspended solids content, as well as nutrients. These characteristics
define the required capacity for secondary treatment, nutrient removal, and solids
handling facilities.
The purpose of this section is to identify current wastewater quantities and
characteristics, and to project future conditions. These projections will be used to
determine the required near-term capital improvements, as well as identify ultimate site
planning issues. Recent plant data was used to develop per -capita flows and loadings and
project future flow and loading conditions.
4.2 Current Wastewater Characteristics
The characteristics of the wastewater, including volumetric flow, organic strength,
suspended solids content, and nutrient loadings, impact the process selection and sizing
of wastewater treatment facilities. Future flow and loadings can be projected from per
capita contributions and population projections.
Key wastewater constituents include biochemical oxygen demand, total suspended solids,
and nitrogen. Biochemical oxygen demand (BOD) is an indirect measure of the organic
strength of the wastewater. This parameter measures the dissolved oxygen consumed in
degrading organic matter. Total suspended solids (TSS) is the particulate matter present
in the wastewater. Nitrogen is a nutrient, and is present in wastewater in both unoxidized
forms (total Kjeldahl nitrogen which includes ammonia [NH4] and organic nitrogen), and
oxidized forms (nitrates and nitrites). In natural aquatic systems, the oxidation of
ammonia to nitrates also consumes dissolved oxygen. An additional consideration is that
non -ionized ammonia is toxic to aquatic life in low concentrations under some pH
conditions.
For the Yakima Regional WWTP, the following general approach was used for
development of projected flows and loadings:
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 4-1
• Collection, trend -plotting, and evaluation of historical flow and loading data.
Data from years 2000 through 2002 were used in the evaluation.
• Establishment of baseline conditions. For the Yakima wastewater system, the
wastewater flows and loadings vary significantly throughout the year due to
impacts from summer irrigation (March through September) and seasonal
industrial discharges from Del Monte (September/October). As a result, annual
average flows and critical design periods were selected as the baseline conditions
or projecting future flows.
• Determining peaking factors to use in calculation of design conditions such as
maximum -month, and maximum -day flow and loadings. The peaking factor is
the ratio of the design condition flow or loading (e.g., maximum month or peak
day irrigation season) to the corresponding annual average flow or load (baseline
condition). In establishing the peaking factors to use for design, the project team
selected conservative, yet characteristic values based on data from the period of
record.
4.3 Historical Flows and Loadings
Historical influent municipal and industrial Annual Average Flow, BOD, TSS, and NH4
data for the Yakima Regional WWTP from 2000 through 2002 are presented in Table 4-
1.
Table 4-1
Yakima Municipal and Industrial Historical Influent Flows and Loadings"3
Year
Flow, mgd
BOD,
TSS,
NH4,
lb/day
lb/day
lb/day,
2000
11.74
23,865
18,757
1,934
2001
11.41
27,625
21,331
1,954
2002
10.70
26,276
17,854
1,565
Average
11.28
25,919
19,321
1,810
1 Annual Average flow and load conditions.
2 Ammonia data adjusted. Questionable data points in 2001 eliminated.
3 These are influent flows and loads that occur during the non -canning season,
without Del Monte flows and loads.
The daily flow trend for years 1994 through 2002 are presented in Figure 4-1. The flow
trend shows influent municipal and industrial flows increasing in the month of March at
the onset of the irrigation season, peaking in August, and subsiding in September -
October of each year. The daily BOD load trend for years 2000 through 2002 are
presented in Figure 4-2. The BOD load trend shows influent municipal and industrial
loads increasing slightly over the 3 -year analysis period. The daily TSS load trend for
years 2000 through 2002 are presented in Figure 4-3. The TSS load trend shows influent
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 4-2
municipal and industrial loads remaining relatively constant over the 3 -year analysis
period.
25.00
20 00
m 15 00
E
LL
c
0
10.00
5 00
Figure 4-1. Yakima Municipal and Industrial Historical Influent Flows
0.00
m $ °zt5n L°
A A A N A N A Uf A J y (0 CO
§A, 1D t0 t0 O O O .8g183
S S
80,000
70.000
0 60.000
0
n
0
a 50,000
O
0
H 40,000
J
c
C
30.000
n
a
0
E
0
20,000
10,000
Figure 4-2. Yakima Municipal and Industrial Historical BOD Load
2.000
2vv
LaCFI m
a O O O
0 a 0 0 0
8 o a
—4—Influent BOD
a
8 10
N N N N
—30 -Day Moving Average
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 4-3
60,000
50.000
a
a
c 40,000
co
co
1—
To R
t 30,000
v
c
is
u 20,000
.9
i
10,000
Figure 4-3. Yakima Municipal and Industrial Historical TSS Load
N
(O
(D
N
V
W
O O O 0 0
a d O O O O O N N N N N a
O N
—InQuent TSS —30 -Day Moving Average
Historical Del Monte Annual Average Flow, BOD, TSS, and NH4 data for the Yakima
Wastewater Treatment Plant from 2001 through 2002 are presented in Table 4-2. The
daily flow trend for years 2001 through 2002 is presented in Figure 4-4. The trend shows
influent Del Monte flow occurs predominately in the months of September and October.
Flows are highly variable, with an average value of 0.33 mgd. The daily Del Monte
BOD load trend for years 2001 through 2002 is presented in Figure 4-5. The BOD load
trend shows influent Del Monte loads increasing slightly over the 2 -year analysis period.
The daily TSS load trend for years 2001 through 2002 is presented in Figure 4-6. The
TSS load trend shows influent Del Monte loads remaining relatively constant over the 2 -
year analysis period.
Table 4-2
Del Monte Historical Influent Flows and Loadings to Yakima Regional WWTP'
Year
Flow,
mgd
BOD,
lb/day
TSS,
Ib/day
NH4, lb/day
2001
0.29
9,877
1,228
5
2002
0.37
10,841
1,228
5
Average
0.33
10,392
1,228
5
t Annual Average flow and load conditions.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 4-4
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
0/ L/6
L0/61/6
LO/6Z/6
LO/CL/01
LO/LZ/OL
LOIOL/LL
L0/9Z/LL
L0/8/ZL
LO/ ZZI
ZO/s/ L
ZO/6L/L
ZO/Z/Z
Z0/9L/Z
Z02/E
ZO/9 L/£
ZO/0£/£
ZO/£L/9
ZO/LZ/9
ZO/L L/S
Zo/SZ/s
2O/9/9
Z02Z19
Z0/9/L
ZO/O /L
Zo/£I8
ZO/LL/8
Zon1.re
Z0/4 L/6
Z0/8Z/6
ZO/ZL/OL
Z0/9Z/OL
Z0/6/ L L
ZO/£z/ L L
Zo/L/LL
Z0/LZ/ZL
Del Monte Influent BOD, ppd
po 0 0 0 0 o 0 p0
0 O O 0 0 0 O S 8
Del Monte Influent Flow, mgd
g O O O O 0 O 0 O 0 0
0 op O IV N W W t L
O O 0 O 0 O 0 0 0 O O 0
Figure 4-5. Yakima Del Monte Historical Influent BOD Load
LO/L1L
LO/ L/Z
L 0/ UE
LO/ L/9
LO/ L/S
LO/ L/9
L0/L/L
L0/L19
L0/116
LO/ L/0L
L011/LL
L01L/ZL
ZO/L/L
Zon/Z
ZO/ L/E
ZO/L/9
Z0/ L/S
ZO/ L/9
Z0/ L/L
ZO/ L/8
ZO/ L/6
ZO/ L/0 L
ZO/L/L L
ZO/ L/ZL
Figure 4-4. Yakima Del Monte Historical Influent Flores
6000
5000
a 4000
a
Vi
1-
r
0 d
0
0
3000
2000
1000
Figure 4-6. Yakima Del Monte Historical Influent TSS Load
i
0
N
Oa
O N Q o
0 O 9 N O N O
O O O O O N N
W W A P cp. C/l m CA V -J CO Oo CO b to
8O C., V - N p `J O O O V '� P CON
o o A`S N 4 f3
O O O O N O N o N O O O O O fel
N N N N N N N N N N N N O `O N O N O
N N N
The total historical influent Annual Average Flow, BOD, TSS, and NH4 data for the
Yakima Regional WWTP from 2000 through 2002 are presented in Table 4-3. These
values are the addition of the municipal/industrial flow and loads,_ and the Del Monte
flows and loads. The highest annual average flow of 11.74 mgd, recorded in 2000, is less
i- is the design annual average flow of 20.7 mgd, and the permit maximum month flow
of 22.3 mgd. Similarly, the current solids (TSS) loading conditions are less than permit
values. The current organic (BOD) loading conditions are greater than permit values.
Table 4-3
Yakima Total Historical Influent Flows and Loadingsl'2
Year
Flow,
mgd
BOD,
Ib/day
TSS,
lb/day
NH4, lb/day
2000
11.74
23,865
18,757
1,934
2001
11.71
37,502
22,559
1,959
2002
11.07
37,117
19,082
1,570
2001-2002 Average
11.62
36,311
20,549
1,815
Permit
22.35
30,300
24,300
-
' Annual Average flow and load conditions.
2 Flows and loads include contribution from Del Monte.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 4-6
Flows have remained relatively constant from 2000 through 2002. Since the 1988
Comprehensive Plan and 1988 Facility Plan Update, the City of Yakima has embarked on
an aggressive sewer rehabilitation program, an aggressive program to rehabilitate existing
irrigation system piping, and the implementation of an industriaVcommercial strong
waste program. It is believed these three factors had a considerable impact on historical
flow and loading data. Flow and loading data for years 2001 through 2002 were chosen
for development of the design conditions. As Del Monte began fully discharging to the
treatment facility in 2001, data from 2000 was only used in the development of baseline
design conditions. Design flow and loading conditions are presented in Table 4-4. In
addition to monthly average and maximum day conditions for baseline data, the critical
design period was selected to coincide with the Del Monte discharge conditions.
Table 4-4
Influent Flows and Loads
Baseline
Baseline +
Del Monte
Baseline
Baseline +
Del Monte
Peak Hour
Annual
Average
Annual
Average'
Max
Month
Max
Month'
Flow
Mgd
11.28
13.6
16.8
15.3
24.0
BOD
lb/d
25,919
36,311
31,171
42,782
TSS
lb/d
19,321
20,549
27,850
29,119
NH4
lb/d
1,810
1,815
2,812
2,822
BOD
mg/L
276
320
331
335
TSS
mg/L
205
181
296
228
NH4
mg/L
19
16
30
22
'For baseline conditions, maximum month loads occurred at annual average flows. For Del Monte
conditions, actual flows during Del Monte discharge were used to calculate maximum month and annual
average concentrations.
The data presented identifies several key features that can be helpful during further
analysis:
• Annual average flow of 11.28 mgd is less than the total average flow measured in
1985-1986 of 17.55 mgd (1988 Facility Plan Update). In addition, the annual
average flow for years 2000-2002 are less than the 19.10 mgd projected for year
2000 in the 1988 Facility Plan Update.
• Maximum daily flows vary from the low -flow season to high-flow season by
approximately 5 mgd, indicating the irrigation season continues to have
significant impact on plant influent flows. Previous collection system evaluations
conducted for the 1988 Comprehensive Plan showed the impact from irrigation is
abrupt, resulting in flow changes that occur within a few days from startup or
shutdown of the irrigation systems.
• During the period between September and October, the highest influent BOD and
TSS loads are experienced at the treatment plant. During this time, irrigation
systems are turned off and influent flows are on the decline. As a result,
peak
- - - -_ ?rr fail,. G,tic� fi`/I/' wr �"!� �•�'''
City of Yakima Wastewater Facility Plan - DRAFT 2126/04 Page 4-7
flow conditions can occasionally coincide with peak organic and solids loading
conditions on an average monthly basis, although plant flow decreases steadily as
the irrigation season ends.
• Average monthly BOD and TSS loadings are relatively constant, with episodes of
extremely high influent loads in September through 0 ber time periods. BOD
measurements increase by a factor of approximately and TS S measurements
increase by a fa
conditions, an
average conditi
• Baseline average
f approximately 1.4 from maxim month to average month
nd 2.50, respectively, when comparing peak day to annual (-1
monthly BOD loadings have increased fro 19, 0 ppd
reported in 2000 to 25,919 ppd, an increase of 33 percent. Baseline average
monthly TSS loadings have increased from 17,820 ppd reported in 2000 to 19,321
ppd, an increase of 8 percent.
4.3.1 Wastewater Unit Flows and Loadings
Projections of future wastewater flow and loadings were performed by first determining
present unit loadings (per capita) for the existing population levels. The unit loadings are
then evaluated to determine whether any changes are anticipated. The unit loadings are
then applied to population projections for the future. The analysis begins with
determination of present unit loadings including residential and commercial, (institutional
and industrial) users.
4.3.2 Unit Flows Determination
Previous planning efforts have separated the residential contribution from commercial
sewage flows by using metered water consumption records provided by the water
purveyors in the area. A domestic sewage flow of 80 gpcd is estimated as a reasonable
value for planning purposes during the irrigation season and 72 gpcd during the non -
irrigation season. Industrial and commercial flows are estimated at approximately 65
gpcd.
Current unit flows for the Yakima Regional WWTP, presented in Table 4-5, are
calculated based on the current population and the total influent flow. This method
attributes all residential and commercial flow, excluding Del Monte, to residents served
by the treatment facility.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 4-8
Table 4-5
Unit Design (Per -Capita) Flows for Yakima Regional WWTP
Design Period
Flow, mgd
Residential
Population 1
Unit Flow, gpcd
BOD,
lb/d
100,000
NH4,
Ib/d
Baseline Conditions
2000-2002
TSS, Ib
pcd
NH4, lb
pcd
Average
11.3
113
Max. Month
16.8
167
Baseline + Del Monte Conditions
2001-2002
Average
11.6
Max Month
17.1
13,321
1,810
1 Estimated residential population for 2002 served by the Yakima Regional WWTP
The average "combined" unit (per -capita) flow based on residential contributions is less
than that used in previous planning studies. The difference is due to changes in water
consumption patterns over the past decade, reductions in infiltration and inflow to the
sewage collection system, and correction to existing irrigation system piping. Also,
conservation and reduced inflow reduce the per -capita projections. For tannin
puTose, it is assumed that the extraneous flow and infiltration/inflow will decrease 3
mgd over the next 20 years during maximum month conditions and 1.5 mgd over the next
20 years during annual average conditions.
4.3.3 Unit Wasteload Determination
Wasteload projections (lb/day influent BOD, TSS, and ammonia) are typically
determined using planning flow projections and average influent concentrations. Due to
the variability in loadings caused by industrial discharges at the Yakima WWTP, a
slightly different approach, similar to that used for development of baseline unit flows,
was used for development of the projected unit loadings. Table 4-6 presents unit (per -
capita) loadings for BOD, TSS, and ammonia for the baseline design period, and annual
average and maximum month conditions based on a Service Area population currently
connected to the Yakima Regional WWTP of 100,000.
Table 4-6
Baseline Unit (Per -Capita) Loadings for Yakima WWTP
Design Period
Influent Loadings
Unit Loadings
BOD,
lb/d
TSS,
lb/d
NH4,
Ib/d
Residential
Population'
BOD,
Ib pcd
TSS, Ib
pcd
NH4, lb
pcd
100,000
Baseline Conditions
Annual Average
25,919
13,321
1,810
0.26
0.19
0.018
Max. Month
31,171
27,850
2,812
0.31
0.28
0.028
Baseline +
Del Monte Conditions
Annual Average
36,311 •
20,549
1,815
Max. Month
42,782 '
29,119
2,822
' Estimated residential population for 2002 served by t
ie wastewater treatment facility.
City of Yakima Wastewater Facility Plan - DRAFT 2/26104
Page 4-9
The unit loadings presented in Table 4-6 indicate the following:
• The influent 30 -day average TSS unit loadings fluctuate significantly between the
annual average and maximum month conditions.
• The 30 -day average BOD unit loadings do not vary as significantly between the
annual average and maximum month conditions.
• Ammonia loadings vary significantly between the annual average and maximum
month conditions analyzed.
• Unit loadings for BOD, TSS, and Ammonia are generally higher than other
similar facilities for the annual average and maximum monthly conditions.
4.4 Projected Flows and Loadings
As the Service Area continues to grow, and as the City of Yakima continues
implementation of the strong waste and industrial/commercial pretreatment program, the
industrial/conunercial influence of high strength wastewater on the per capita unit
loadings is not expected to increase. The Del Monte influence is independent of
population and is, assumed to remain constant over the planning period. Table 4-6
identifies the per capita loadings of flow, BOD, TSS, and ammonia to be used in this
Wastewater Facilities Plan.
These future per capita unit loadings are similar to those used in previous planning
studies for the Yakima Regional WWTP, and are anticipated to be conservative. The
projections for future wastewater characteristics will be based on providing service to the
entire population residing within the existing and future Service Area.
Table 4-7 shows the projected flows and loadings for the Yakima Regional WWTP.
These values were developed using the population projections presented in Section, and
baseline unit flows and loads presented in Tables 4-5 and 4-6. The peak conditions for
BOD and TSS are higher for September through October critical design months, due to
Del Monte. Del Monte loads are assumed to remain constant through the 20 -year
planning period.
/CU etZ #4(,
F 11
//610/4i t
Oestri �
Page 4-10
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Table 4-7
Projected Flow and Loadings for the Yakima Regional WWTP
Year
Condition
Flow, mgd
BOD, lb/d
TSS, Ib/d
NH4, Ib/d
2004
Baseline Conditions
-\
Annual Average
11.7
46,956 ,)
20,094
1,882
Max Month
17.4
32,418
28,964
2,924
Del Monte Conditions
Annual Average
12.17
37,348
21,322
1,887
Max Mouth
17.8
44,028
30,233
2,934
Peak Hour'
24.8 /
\
/CU etZ #4(,
F 11
//610/4i t
Oestri �
Page 4-10
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Table 4-7
Projected Flow and Loadings for the Yakima Regional WWTP
Year
Condition
Flow, mgd
BOD, lb/d
TSS, lb/d
NH4, Ib/d
2009
Baseline Conditions
Annual Average
12.3
29.159
21,736
2,036
Max Month
18.1
35,068
31,332
3,163
Del Monte Conditions
Annual Average
12.6
39,551
22,964
2,041
Max Month
18.5
46,678
32,601
3,173
Peak Hour
26.1
2014
Baseline Conditions
Annual Average
13.3
32,270
24,055
2,253
Max Month
19.3
38,808
34,674
3,501
Del Monte Conditions
Annual Average
13.6
42,662
25,283
2,258
Max Month
19.7
50,418
35,943
3,511
Peak Hour
28.2
2019
Baseline Conditions
Annual Average
14.2
35,121
26,180
2,453
Max Month
20.4
42,237
37,737
3,810
Del Monte Conditions
Annual Average
14.5
45,513
27,408
2,458
Max Month
20.8
53,847
39,006
3,820
Peak Hour
30.1
2024
Baseline Conditions
Annual Average
15.5
(38,978
29,056
2,722
Max Month
22.2
46,876
41,882
4,229
Del Monte Conditions
Annual Average
15.8 1
491370
30,284
2,727
Max Month
7-22-.6 .0
58,486
43,151
4,239
Peak Hour' 32.9
(..'
Build Out
Baseline Conditions
Annual Average 18.5
46,007
34,295
3,213
Max Month 26.7
55,329
49,434
4,991
Del Monte Conditions
Annual Average 18.9
56,399
35,523
3,218
Max Month 27.1
66,939
50,703
5,001
Peak Hour 39.2
I Based on a peaking factor of 2.12 to the baseline annual average flow. i. S 01.7 C014/o4.vifk
Feo"t �uS 3 -tom
Loo y t o 5, 653
«310 t19 L.0
2tl r5 f" 7°11
9.,)tO loo 96)
f
foi
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
zvtiLl tsoM
Page 4-11
SECTION 5
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT
5.1 Introduction
The purpose of this section is to summarize existing design flow and loading capacity and
remaining capacity for each unit process at the Yakima Regional WWTP. Additionally,
operation and maintenance practices and treatment plant staff issues are reviewed. The
analysis is based on the following:
• A review of operating data from January 1993 to December 2002. Following
additional data analysis, operating data from January 2000 to December 2002 was
used to establish current flows and loads.
• Criteria for Sewage Works Design, Washington State Department of Ecology,
Ten States Standards, and other design publications, which are used to establish
existing facility capacity.
• Interviews and meetings with treatment plant staff conducted to evaluate current
operation and maintenance activities and identify safety, reliability, and capacity
issues familiar to plant personnel.
5.2 Description of Existing Facilities
The existing Yakima Regional WWTP is located east of Interstate 82 and south of State
Route 24. The facility began operation in 1936 as a primary treatment plant. In 1965, the
treatment facility was expanded with the addition of the trickling filters to provide
secondary treatment. An activated sludge system expansion with aeration basins and
final clarifiers was completed in 1983. In 1992, additional modifications were made to
improve treatment processes including:
• Installation of new trickling filter pumping.
• Increase laboratory space.
• Provide enhanced chlorination and dechlorination facilities.
• Installation of air emission equipment.
• Additions to the solids handling capacity.
• Extension of the outfall.
• Miscellaneous operating improvements.
In 1995, miscellaneous improvements were made to mechanical systems at the facility
and in 1996, improvements to the facility Headworks and Digestion facilities were made,
including:
• Installation of new influent flow meters (Parshall Flumes).
• Installation of Headworks air emission control.
• Installation of new mechanical bar screens and screenings handling equipment.
• Construction of new grit removal systems.
• Installation of fixed covers and top entering mixers on the primary digesters.
• Replacement of piping in the primary digester pumping building.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 5-1
• Installation of flexible membrane digester gasholder covers for the secondary
digesters.
• Miscellaneous operating improvements.
In 2002, improvements were made to the Trickling Filter system which allowed for
control of the distributor arm speeds and better trickling filter clarifier operation. These
improvements included the following:
• Installation of a bypass from the trickling filter pump station to primary clarifiers.
• Installation of two vertical turbine pumps at the trickling filter clarifier effluent
pump station.
• Installation of motorized mast type rotary distributor center assemblies for the
trickling filters and modification of distributor arms.
• Installation of trickling filter clarifier sludge line to the DAFT.
• Addition of a trickling filter sludge pump enclosure, with new pump to discharge
trickling clarifier solids to the DAFT and to the Headworks facility.
A liquid treatment process schematic of the existing Yakima Regional WWTP is shown
on Figure 5-1 and an existing solids process schematic is presented in Figure 5-2.
Existing facilities and equipment are presented in Table 5-1. Figure 5-3 illustrates the
hydraulic profile for the existing facilities. Figure 5-4 shows a layout of the existing
plant facilities.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 5-2
K-wA1 RAMO
on or mom S4IDI
1100 ROAD
MOM SIALOI
IJAIA NO
IMWW
nMOMS .0011%
r,,
la
CAST
S7WCt t
MWD
oy/Au
Ulla WM
14/
0
BLACK & VEATCH
Black & Veatch Corporotion
Seattle, Washington
FIGURE 5-1
CITY OF YAKIMA
YAKIMA REGIONAL WASTEWATER TREATMENT PLANT
EXISTING LIQUID PROCESS SCHEMATIC
10 V7
510
W1
awlsou
7+utn7r
1a1a
0[p11w
Ip 1
001
107
00p1101
10.7
T CI1 01(
M14011 10 MIMICLIMIDI NUM
OW WNW
�1101q
J
1111,3
11
20 44/os
4
10 WO U*.IMI
�mf1fI1Q b 7
J�OD11rU0i 1d 1
10 M7
AOM
70" 10 try
MOW
COMO
MOS
1n1
lie
MP 7107
P
FIGURE 5-2
0
BLACK & VEATCH
Block & Veatch Corporation
Seattle, Woshington
CITY OF YAKIMA
YAKIMA REGIONAL WASTEWATER TREATMENT PLANT
EXISTING SOLIDS PROCESS SCHEMATIC
1030
1025
1020
1015
1010
1005
1000
995
990
985
1010
1005
1000
995
990
985
980
975
970
1008.65
LEGEND:
1006.91
1006.49
1008.22 1007.02 1006.27
1005,50
OAR SCREEN
PEAK FLOW 9 24 IIGO (Ida YEAR RIVER EL)
AVERAGE FLOW @ 11.28 l (00014L RIVER EL) \
1000.57
000.34
mo".
1006.12
1005.4
VORTEX
DEGRRTER
1002.23
1001.83
PRIMARY
CLAVIER
DISTRIBUTION
STRUCTURE
TRICKLING FIL ER CLARIFIER
TRICKLING FILTER CLARIFIER
EFFLUENT PRIMP STATION
PRIMARY
CLAR1RER
1001,51
00
1001.70
PROAART
CLARIFIER
EFFLUENT
BOX
1002.74
ni8T,T8—\\a
TRICKLING
FILTER
PUMPING
STATION
1001.37 999.28
1001.25 \ .. +.78
999.07
3
AERATION BA51H5
SECONDARY CLARIFIER
SECONDARY
EFFLUENT
STRUCTURE
CHLORINE
1AIX111G
CHAMBER
14/
0
BLACK & VEATCH
Black & Veatch Corporation
Seattle, Washington
TRICKLING
FILTERS
998.95 997.87
*998. 1\ 996.69
CHLORINE
CONTACT TANK
1002.48
997.76 997.68 997.48
7
OUTFALL
CONNECTION 80X
OUTFALL
STRUCTURE
INTERUEDATE
DEGRITTER
BYPASS
100 YR RIVER
EL 997.4
NORMAL RIYER
EL 988.60
1030
1025
1020
1015
1010
1005
1000
995
990
985
1010
1005
1000
995
990
985
980
975
970
FIGURE 5-3
CITY OF YAKIMA
YAKIMA REGIONAL WASTEWATER TREATMENT PLANT
EXISTING HYDRAULIC PROFILE
Table 5-1
Existing Facilities and Equipment
Parameter
Units
Value
Air Emission, Scrubbers
Number
2
Type
Vertical packed tower
Vessel Diameter
ft
9
Treatment Bed Depth
ft
10
Capacity, each
cfin
24,000
Rudkin Road Pumping Station
Number of Pumps
4
Type
Submersible, non -clog,
centrifugal
Capacity
gpm
2 @ 1,200
gpm
2 @ 2,700
Horsepower
HP
2 @ 35
HP
2 @ 77
Drive Type
Variable Frequency
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-13
5.3 Process Analysis
The capacity of the treatment system is established in this section, with the basis of the
analysis detailed and the resulting plant capacity established in this section. Additional
detail is provided for each unit process in Section 5.4.
5.3.1 Basis
Like sanitary sewers, the capacity of the wastewater treatment plant is linked to its ability
to transport a volumetric quantity of wastewater. Wastewater treatment plant capacity is
also defined in terms of its capacity to treat organic and solids loadings. Organic strength
is measured by biochemical oxygen demand (BOD) and anunonia (NH4), and solids
strength by total suspended solids (TSS). Treatment unit sizing is based upon hydraulic,
organic, and solids criteria.
A mass balance model of the treatment plant was developed. Primary clarifier removal
efficiencies were calculated using plant influent data and projected return flows to
represent primary influent. The reported primary clarifier influent data were not used,
because these values were very high and operators indicated that the sampling point may
not yield a representative sample. Primary effluent data was used with the projected
influent data to obtain BOD and TSS removal efficiencies of 36 and 51 percent
respectively. It was assumed that the current removal efficiencies would remain constant
up to the allowable maximum surface overflow rate of 1200 gpd/sf. Trickling filter
loading was limited to 90 lb/kcf/d or about 11.8 mgd, with the remainder of the flow sent
directly to the aeration basins. A detailed analysis of the trickling filters can be found in
Section 5.4.3.3. Trickling filter clarifier BOD and TSS removals were assumed to be 40
and 60 percent respectively, with effluent sent to the aeration basins. The capacity of the
aeration basins was assessed assuming operation with MLSS at an upper limit of 3,000
mg/L while maintaining an SRT long enough to provide nitrification during cold weather.
It was assumed that all four basins could be operated under aeration with no anoxic zone.
A detailed analysis of the aeration basins can be found in Section 5.4.3.7.
The calibrated model was then applied to evaluate individual unit process capacity at the
projected future load conditions at 5 -year intervals. Unit processes were evaluated under
Baseline annual average (AA) and Del Monte maximum month (MM) conditions. The
AA conditions represent an average "baseline" during the year, without the seasonal Del
Monte discharge. The MM conditions include the domestic monthly maximum in
conjunction with the Del Monte industrial discharge. In addition, hydraulically limited
processes were evaluated at peak hour (PH) flow conditions. At each of the future design
loading conditions, unit processes were compared to the established design criteria to
determine whether capacity was sufficient.
Solids quantities were generated using the mass balance model and verified using plant
data. Solids concentrations used in the evaluation were based on 2002 — 2003 plant data.
Projected solids quantities are presented in Table 5-2. The average total solids quantity
projected for 2004 is just slightly higher than the 2002 — 2003 reported quantity of 18,200
ppd. However, the maximum month solids quantity projected for 2004 is much higher
than the reported maximum month. This is because it was assumed that the maximum
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 5-14
month domestic and Del Monte loads occur at the same time. Based on present data, the
two maximum month loadings have not yet coincided, but there is no reason that this
condition could not occur in the future.
Table 5-2
Solids Quantities
Solids
2002
2004
2014
2024
All quantities in ppd
AA
MM
AA
MM
AA
MM
AA
MM
Primary Solids
8,800
11,700
9,100
12,500
10,800
15,300
13,000
19,000
Trickling Filter
6,000
11,800
6,300
11,200
7,700
11,500
9,500
12,000
WAS
5,300
6,700
5,500
7,400
6,300
10,000
7,500
13,000
Total
20,100
30,200
20,900
31,100
24,800
36,800
30,000
44,000
Solids process capacities were determined based on 5 day, 24 hour operation for
dewatering and 7 day, 24 hour operation for thickening and digestion. Since solids
generation rates are not expected to increase in a linear fashion, due to a greater volume
of solids by-passing the trickling filters in the future, solids process capacities were
evaluated using the model results, which extended only through 2024, with an associated
MM flow of 22.6 mgd. The values in Table 5-3 show the capacity of the major process
treatment units under the conditions stated. Detailed analysis for each major process can
be found in subsequent sections.
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 5-15
Table 5-3
Rated Capacity (mgd) of Unit Processes under various Operating Criteria
Unit Process
Parameter
Condition
Limit
Unit
Baseline
Average
Annual
Del
Monte
Max
Month
Peak
Hour
Primary Clarifiers
OFR
AA
1200
gpd/sf
30.5
Primary Clarifiers
OFR
PH
2500
gpd/sf
63.6
Trickling Filters
OLR
AA
60
ib/kcf/d
13.0
Trickling Filters
OLR
MM
90
lb/kcf/d
1 1.8
Aeration Basins
MLSS
MM
3000
mg/L
15.0
Secondary Clarifiers
HRT
PH
2
Hr
31.4
Secondary Clarifiers
OFR
AA
600
gpd/sf
18.0
Secondary Clarifiers
OFR
PH
1200
gpd/sf
36.5
Secondary Clarifiers
SLR
AA
24
lb/d/sf
16.0
Secondary Clarifiers
SLR
MM
30
Ib/d/sf
16.3
Chlorine Contact Basins
HRT
AA
60
min
19.4
Chlorine Contact Basins
HRT
PH
20
min
58.2
DAF Thickeners (without
polymer)
SLR
MM
0.4
lb/hr/sf
20.1
DAF Thickeners (with
polymer)
SLR
MM
1.0
lb/hr/sf
>22.62
Anaerobic Digester
SRT
MM
15
days
19.7
Centrifuge
Flow
MM
240
gpm
> 22.62
DAFT capacities evaluated using 24 hour/7 day operat ng schedule
2Capacity exceeds that required for solids projected at 2024 conditions (22.6 mgd)
Where:
AA = Annual average condition
MM = Maximum month condition
PH = Peak hour conditions
HRT = Hydraulic retention time
SLR = Solids loading rate
SRT = Solids retention time
OFR = Overflow rate
OLR = Organic loading rate
5.3.2 Plant Capacity
The total capacity of the biological system, including the primary clarifiers, trickling
filters, trickling filter clarifier, aeration basins and secondary clarifiers, is 53,400 ppd of
total influent BOD (with corresponding flows of 14 mgd) during maximum month
loading conditions and with Del Monte loads. The current plant processes will provide
capacity until 2018, when additional aeration basin capacity is required. This is depicted
on Figure 5-5. This capacity is based on the following qualifications:
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-16
• The organic loading capacity is 53,400 ppd BOD and the solids loading capacity
is 38,600 ppd TSS. These loading rates assume maximum month influent loading
from both the domestic contribution as well as Del Monte.
• The maximum month capacity does not include redundancy requirements.
• The evaluation assumes the load to the trickling filter will remain at or below 90
ppd/kcf and the MLSS in the aeration basins will remain at or below 3,000 mg/L.
80000
70000
60000
50000
0
m
40000
d
• 30000
- • 20000 -
Figure 5-5 Plant Organic Capacity
10000
0
Current Plant Organic
capacity = 53,400 Ib/day
Capacity = 65,400 Ib/day
with new A -Basin
Capacity without Trickling
Fitters = 25,000 Ib/day
• Maximum month
• Baseline & Del Monte
projected BOD load
Capacity without Trickling Filter
Clarifier = 40,000 Ib/day
Maximum month Baseline
projected BOD Toad
(without Del Monte)
ryo ry0 CVt.ryo ry0 O
�
a
CO
Year
The annual average capacity of the biological system expressed in terms of equivalent
plant flow is approximately 21.5 mgd, which will provide sufficient capacity to meet
buildout conditions. (The annual average projected design flow for buildout conditions is
18.5 mgd.) This capacity is based on the following qualifications:
• At buildout, the projected annual average loadings are 46,000 ppd 130D and
34,300 ppd TSS.
• The annual average capacity does not include redundancy requirements.
The annual average organic capacity of the biological system expressed in terms of plant
flow is much greater than the maximum month capacity (21.5 mgd vs 14 mgd) due to the
significantly lower loads of BOD received during the non -canning season.
It is important to note that the plant may currently exceed the 14 mgd maximum month
flow value. This is a result of domestic influent loadings occurring at conditions less than
maximum month while Del Monte loading is occurring. The more important capacity
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-17
limitations are the organic loading capacity of 53,400 ppd BOD and solids loading
capacity of 38,600 ppd TSS.
Fixing the loading capacity of the WWTP at these values, and then presuming maximum
month non -canning season BOD and TSS concentrations (primarily mixed domestic
loads) are being received at the WWTP headworks, the maximum month treatment
capacity of the WWTP is projected to be 20.2 mgd.
For purposes of providing loading limits for Section S4. FACILITY LOADING of the
NPDES permit, the following values should be incorporated:
Average flow (max. month) 20.2 mgd
BOD5 loading (max. month) 53,400 ppd
TSS loading (max. month) 38,600 ppd
Design population 130,000
5.4 Process Unit Capacity Evaluation
The information provided in Tables 5-4, combined with the information provided by
operations staff in meetings conducted in December 1998, January 1999, and June 2003
was used to assess the condition and capacity of the individual unit processes. The
findings on each individual unit process are described in the following paragraphs.
5.4.1 Preliminary Treatment
The preliminary treatment evaluation includes assessment of condition and capacity of
the headworks building, bar screens and screenings compactor, influent building, grit
removal, septage treatment and dumping facilities, and flow measurement.
5.4.1.1 Headworks Building
The mechanical bar screens and screenings compactors are housed in an enclosed CMU
block building with concrete hollow core roof. Building access includes a 6'-O" X 7'-l0"
insulated metal door along the South wall and a 12'-0" X 12'-0" insulated steel door
along the North wall. Air emission control is provided for this building via ventilation
through the covered influent channels.
5.4.1.2 Bar Screens and Screenings Compactor
Two mechanical bar screens are located in the Headworks Building. The screens collect
and dispose of debris from the two 3 foot 6 inch wide influent channels. The bar screens
are fitted with bar racks with clear openings between bars of %2 inch. The bar screens
discharge into two associated screenings compactors, each rated at a minimum of 35
cubic feet per hour and 50 percent volume reduction. Each bar screen is installed with
upstream and downstream ultrasonic levels to control collection frequency.
Operations and Maintenance Issues
• The compacted screenings discharge into an open dumpster in the screenings
room.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-18
Process Rating
The mechanical bar screens have a combined peak hour hydraulic capacity of 80 mgd (40
mgd per unit). The current peak hour flow of 24.0 mgd can be easily accommodated with
the existing bar screen units. Annual average flows are currently at 11.28 mgd, well
below the capacity of one bar screen. Should one mechanical bar screen be removed
from service, sufficient redundancy exists with one unit to handle the current annual
average flows. Sufficient capacity is available with the existing system to handle the
projected peak hour flow of 32.9 mgd in year 2024. Annual average flows for 2024 of
15.5 mgd are also below the capacity of one bar screen providing sufficient redundancy
to handle future annual average flows.
5.4.1.3 Influent Building
The Influent Building houses the grit handling facilities, septage receiving, engine
generator and electrical room. The grit removal pumps serving the forced vortex grit
removal units are located in the lower level of this building. Access to the building is
provided via man doors on the West and South sides of the main floor, a double man door
on the East end of the electrical room, and an overhead door on the East end of the grit
loadout and septage dumping station.
Operations and Maintenance Issues
• Truck access to the septage dumping and grit loadout facility is cumbersome.
Trucks must back into the facility. The facility is infrequently used for septage
receiving.
5.4.1.4 Grit Removal
Wastewater flow is diverted via the two influent channels into two 16 -foot diameter
forced vortex -type grit basins. Each basin is fitted with basin paddle drives operated by 2
Hp drive units, operating in opposing directions. Captured grit is pumped from the Grit
Basins to the Influent Building with two 15 hp centrifugal recessed impeller pumps and
discharged to two grit cyclone/classifier units. Dewatered grit is discharged into a single
400 cubic foot grit storage hopper fitted with motor operated knife gate and vibratory
loadout system. The hopper can hold approximately 300 cubic foot of grit. Grit is
discharged in to a truck for hauling to disposal at a landfill operation.
Operations and Maintenance Issues
• Grit volumes do not appear to have changed significantly since the new forced -
vortex type grit basins were installed.
• Several problems exist with the grit storage hopper including:
o The initial installation changed the gear box and drive for the vibratory
system. Cracking of welded joints has occurred at the vibratory unit
connections.
o Old vibratory units were installed on a new tank during the last system
upgrade.
Process Rating
Each forced vortex grit basin has a hydraulic capacity of 5 mgd minimum design flow
and 20 mgd peak flow. This places the fixed hydraulic capacity of the grit removal
system at 40 mgd, in excess of the current peak hour flow of 24.0 mgd. Inside the
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-19
Influent Building, grit is conveyed through two grit cyclone and screw classifiers. Each
of these units has a capacity of 205 gpm and can remove up to 1.5 tons (approximately 1
cubic yard) of grit per hour. Each cyclone is fed from variable speed pumps, each capable
of delivering 200 gpm flow.
The grit cyclones and classifiers currently remove approximately 3-5 cubic feet per
million gallons (1.33-2.22 cubic yards per day under annual average flow conditions). As
such, the capacity of the grit handling systems is well in excess of current and projected
loading conditions. Organic content in the grit is low, indicating effective separation and
washing is provided by the system.
5,4.1.5 Septage Treatment and Dumping Facilities
The septage receiving facility is located inside the Influent Building. Transported
septage is disposed directly into two septage sumps beneath the main floor and conveyed
to the treatment process through two recessed impeller pumps, rated for 200 gpm. The
septage pumps deliver the septage through a 4 -inch force -main to the influent channels,
located immediately upstream from the bar screens.
Operations and Maintenance Issues
• Domestic septage is currently accepted at the Cheyne Landfill. The Yakima
Regional WWTP does not allow industrial septage dumping due to the risk of
toxic chemicals being introduced into the WWTP.
• The existing facility is located in an area of the plant that is not easily accessible.
• Proper washdown facilities are not provided.
• Provisions for cleaning of trucks are not provided at the facility.
• Screening for rocks, bottles, etc. is not adequate.
• Volume and weight measurement should be improved.
• Septage room is also used for grit loading.
5.4.1.6 Flow Measurement
Influent flow measurement is provided at two 48 -inch Parshall flumes, located in open
concrete channels adjacent to the Influent Building and downstream from the forced
vortex -type grit basins. Ultrasonic level measuring and transmitter devices installed at
each flume provide flow measurement. The flumes can operate individually or in parallel
with flows totalized.
Process Rating
Individual flume capacity is 0.8-30.0 mgd, resulting in a fixed metering capacity of up to
60.0 mgd, well in excess of current and projected peak hour flows.
5.4.2 Primary Treatment
The primary treatment evaluation includes assessment of condition and capacity of the
flow split, primary clarifiers, primary sludge pumping, primary scum pits, and sludge
transfer building.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-20
5.4.2.1 Flow Split
Wastewater flows from the Parshall flumes through channels and into the primary
clarifier diversion structure. Each open channel empties into a split box chamber which
then feeds two clarifiers from each of the two channels. Flow exits the distribution box
through four 30 -inch Primary Clarifier influent pipes controlled with sluice gates.
Manual regulation of the sluice gate positions are used to set the flow split to each of the
four primary clarifiers. Ten -inch telescoping valves are located in each chamber for scum
removal.
Operations and Maintenance Issues
• The influent box configuration still traps scum, grease and other floatables, even
following installation of the telescoping valves. Scum removal is manual at this
time.
• Influent solids tend to be directed straight ahead creating a poor solids flow split
that directs more solids to Primary Clarifiers 2 & 3.
• The sluice gates controlling flow to each primary clarifier leak. Isolation of the
primary clarifiers is difficult.
• Flow measurement is not available at each primary influent pipeline for
measurement of the flow split.
5.4.2.2 Primary Clarifiers
Four 90 -foot diameter primary clarifiers with an 8 -foot side water depth and 12:1 bottom
slopes are available. Six-inch sludge and scum pipes service the clarifiers with scum
flow combining into North and South scum pits. Twenty-four inch effluent pipes transfer
clarified primary effluent to a chamber in the Sludge Transfer Building where flow is
combined and exits through a 48 -inch primary effluent pipe. The number of clarifiers
placed into service is determined by influent flow conditions. Operations staff maintains
basin detention time to 1.0 to 2.0 hours. Typically, two to three clarifiers are placed in
operation to handle current flow conditions.
Operations and Maintenance Issues
• The sludge collection mechanisms are 1936 vintage equipment that were
rehabilitated in 1978 and repainted in 1992 and 1995. Sand blasting of the
mechanisms caused sand to get into the gear assemblies. Plant staff is concerned
about the condition of the gear assemblies.
• The mechanisms' collector arms need adjustment to the bottom slope.
• The area in the vicinity of the clarifiers has settled. Settlement of the basins is
also a concern. There is also some settlement around the outside of the basins
along the perimeter sidewalks and under the basin influent channels.
• Birds accessing the primary clarifiers are a reported problem.
• Scum skimmers could use improvement.
• Weir cleaning and safety needs to be addressed.
• Odor control capability is desired.
Process Rating
The primary clarifiers have excess capacity to treat existing flows. Under current annual
average conditions, the primary clarifier surface overflow rate (SOR) is 444 gpd/sf with
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-21
all four basins in service, compared to WDOE upper limits of 1200 gpd/sf. At peak hour
conditions the SOR is 943 gpd/sf, which is below the WDOE upper limits of 2,000 to
3,000 gpd/sf. The maximum hydraulic retention time recommended by WDOE is 2.5
hours and Black & Veatch uses a more conservative design hydraulic retention time of 2
hours during average flow conditions. Primary clarifiers are rated based upon hydraulic
retention time (HRT) and overflow rate (OFR). In the case of Yakima, the OFR criteria
control the capacity. The rated capacity of the primary clarifiers is 30.5 mgd during
annual average daily flow conditions or 63.4 mgd under peak flow conditions.
The reliability standards (Class I and Class II) of WDOE require that the primary
sedimentation system be able to handle at least 50 percent of the total design flow with
the largest unit out of service. At buildout conditions flows will reach 18.5 mgd under
annual average conditions. Because 4 primary clarifiers are available, Yakima meets this
redundancy criterion without difficulty. The primary overflow rate at 50 percent of the
18.5 mgd annual average flow (9.25 mgd) will be 485 gpd/sf with 3 basins in service.
The overflow rates throughout the design period are listed in Table 5-4.
Table 5-4
Primary Clarifier Overflow Rates
WDOE Requirements
4 Basins in Service
3 Basins in Service
Design
Flow
Overflow
rate
50% of
Flow
Overflow rate
Year
mgd
Gpd/sf
mgd
gpd/sf
Current
11.3
444
5.7
296
2004
11.7
460
5.9
307
2009
12.3
483
6.2
322
2014
13.3
523
6.7
348
2019
14.2
558
7.1
372
2024
15.5
609
7.8
406
BO
18.5
727
9.3
485
5.4.2.3 Primary Sludge Pumping
Sludge and scum are withdrawn through six air -diaphragm (ODS) pumps located in the
Sludge Transfer Building, each with a capacity of approximately 50 gpm in their current
installed condition. Flow measurement is provided through stroke counting of the ODS
pumps which are operated alternately. Typical alternation is one stroke every 20/30/40/50
seconds, depending upon the number of pumps on-line. Only one pump is allowed to
stroke at any given time. Operations personnel check clarifier sludge blanket depth and
primary sludge concentration frequently to determine pumping rates. Combined solids
concentration of the primary sludge is typically maintained at 4.5 to 5.5 percent.
Operations and Maintenance Issues
• Thickening in the clarifiers to greater than 6 percent solids concentrations is
problematic for subsequent pumping.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-22
• Measurement of primary sludge and scum flows via stroke counting has accuracy
and repeatability issues associated with the method of measurement.
• Density measurement on discharge of primary sludge pumping is not provided.
• Operation of the Primary Sludge Pumps is staggered (i.e. I stroke every
20/30/40/50 seconds). One pump is allowed to stroke at a time.
• Primary sludge pumping has occasionally encountered serious grease and
plugging issues. Alternate arrangements should be investigated. The City has
also implemented a pretreatment Fats, Oils and Grease program.
Process Rating
The primary sludge and scum pumps are arranged for 100 percent redundancy of
pumping units, and meet WDOE Class I and II reliability requirements for pumping of
the solids at the current loading rates.
5.4.2.4 Primary Scum Pits
Two 4'-O" X 4'-0" scum pits are located at the North and South end of the sludge transfer
building. The North pit serves Primary Clarifiers Nos. 1 and 4 and the South pit serves
Primary Clarifiers Nos. 2 and 3. The North pit also collects scum from the telescoping
scum removal valves in the primary influent split box.
Operations and Maintenance Issues
• The piping from the clarifier scum troughs to the scum pits tend to plug. Cleanup
and removal of plugging takes a considerable amount of time. Piping bends and
existing pipeline condition are suspected as key reasons for the plugging
problems.
5.4.2.5 Sludge Transfer Building
The sludge transfer building is centrally located between the four Primary Clarifiers. It
houses the four air -diaphragm sludge pumps, 2 air -diaphragm scum pumps, and 1
dewatering purnp in the lower level. It also holds the primary effluent outlet box that
combines primary effluent flows in a lower level chamber and directs these flows through
a 48 -inch outlet pipe to downstream treatment processes.
Operations and Maintenance Issues
• Access doors to the building are in very poor condition and require replacement.
• Toilets and sinks within the building are discharged upstream from the trickling
filter influent distribution box so do not receive appropriate primary treatment.
The location of the sump discharge should be relocated.
• Sludge discharge piping has clogged in the past requiring replacement.
Operations staff has added non -potable water connections to provide flushing.
• The air -diaphragm pumps are 25 years old and have difficulty pumping primary
sludge. Plant staff also has problems with the existing air compressors.
Replacement of the air -diaphragm pumps with other types of pumps (i.e.,
progressing cavity) need to be considered.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-23
5.4.3 Secondary Treatment
The secondary treatment evaluation includes assessment of condition and capacity of the
flow split, trickling filter pumping station, trickling filters, intermediate degritter,
trickling filter clarifier, activated sludge system, secondary clarifiers, RAS pumping, and
WAS and secondary scum pumping.
5.4.3.1 Flow Split
Primary effluent and food processing waste flows enter the north side of the structure
while trickling filter recirculation enters on the southeast side. The multiple chamber
structure directs flow through a series of openings and water control gates that distribute
primary effluent to the trickling filter pumping station or the activated sludge system
aeration basins. Flow to the Aeration Basins may be conveyed directly through a 54 -inch
bypass pipeline when the flow control system is not working, or when the trickling filter
system is not in operation. Alternatively, flow may be directed to the aeration basins
through a 24 -inch bypass pipe with ultrasonic flow meter and a 54 -inch pipe. The flow
control system is used to ensure a minimum amount of primary effluent is delivered to
the aeration basins to supply necessary nutrients (food) to the biomass. During baseline
conditions, the trickling filters are lightly loaded and effluent concentrations are low, so a
portion of the primary effluent flow (about 2 mgd) is bypassed directly to the aeration
basins to maintain sufficient loading. However; during Del Monte flow, the entire flow is
routed through the trickling filters as the remaining load is adequate to maintain the
activated sludge process. A modulating sluice gate (gate SL201 is preferred and typically
used) controls the splitter box level which allows the desired amount of flow to bypass
directly to the aeration basins The trickling filter clarifier is currently utilized to remove
solids from the trickling filter effluent.
Operations and Maintenance Issues
• If sluice gate SL202 is used for the flow split control (which is not typical), the
gate motor experiences considerable modulation and wear on the lift nut on the
gate electric operator.
5.4.3.2 Trickling Filter Pumping Station
The Trickling Filter Pumping Station is located adjacent to the primary effluent flow split
structure. Four submersible non -clog centrifugal pumps are used to force flow to the
North and South Trickling Filters. Wastewater flow exits the pumping station through
one of two 24 -inch force mains and into a metering vault where ultrasonic flow meters
and control valves control discharge to the Trickling Filters. A new 16 -inch bypass pipe
from the trickling filter pump discharge connects to the section of the primary clarifier
flow split structure which splits flow into Primary Clarifiers No. 3 and No. 4.
Process Rating
Discharge piping is connected with headers allowing full pump redundancy. Capacity of
the Trickling Filter Pumping Station is set at the firm capacity of the pumping units.
Estimated station capacities with 1, 2 & 3 pumps in operation are 15.3, 27.4 and 36.0
mgd respectively. With at least one redundant unit, the pump station satisfies WDOE
Class I and Class II reliability requirements. The two trickling filters can only be
operated in parallel, and it is not possible to segregate the effluent flow of one unit from
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-24
the other. Although not typical operation, three pumps can be operated to serve the two
trickling filters with the fourth pump serving as a redundant unit. This limits the capacity
of the pumping station to the capacity of the trickling filter's rotary distributors at 12,000
gpm per trickling filter, or 36.0 mgd for the pumping station. The organic capacity of the
trickling filters is more restrictive (as noted in later paragraphs) than the hydraulic
capacity of the pumping station.
5.4.3.3 Trickling Filters
Two 170 -foot diameter Trickling Filters are available. Wastewater from the primary
clarifiers enters the trickling filter pumping station where it is mixed with trickling filter
recirculation flow before being pumped to the trickling filters. Each filter contains 8 -feet
of rock media.
Operations and Maintenance Issues
• A snail problem exists in the filters, and an intermediate degritter facility was
installed to mitigate the effects of snails on downstream processes. Plant staff
would like to determine other methods to control snails when filter is taken offline
and also when filter is in service.
• Water and ice are falling off the trickling filter dome covers, above access doors,
and around the air emission blowers. This poses safety issues.
• Ice sometimes builds up and water accumulates around the intermediate degritter.
• Doors and closure units have rusted off. Plant staff expresses desire to replace
with non-metallic materials.
Process Rating
Under current operations, two recirculation pumps are operated with each pump
dedicated to an associated trickling filter. The total flow, which includes primary effluent
and trickling filter recirculation is approximately 27.4 mgd. The current annual average
organic loading rate is 42 ppd/kcf. The current maximum month organic loading rate is
90 ppd/kcf, which corresponds to 32,670 ppd BOD. The organic loading rate is limited
to 90 ppd/kcf, because the units have demonstrated effective treatment under those
conditions, as illustrated in Figure 5-6. In addition, increasing the organic loading rate
above 90 ppd/kcf could Lead to plugging, sloughing, and decreased performance of the
trickling filter system. At this organic load limit, the maximum month hydraulic loading
rate is about 11.8 mgd, so the trickling filters are currently operated at maximum capacity
with Del Monte. Any load above this limit should be routed directly to the aeration
basins. The annual average and maximum month loading rates for the design period are
shown in Table 5-5. For future years, the organic loading rate is constant, but the
hydraulic rate increases because BOD concentrations decrease as the municipal
component increases and Del Monte flow remains fixed.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-25
Figure 5-6. Trickling Filter Loading Rate
TF Effluent BOD
25,000
20,000
15,000
10,000
5,000
0
0
Max Month
TF Effluent = 23,000
ppd
1
Modified \ elz equation (k=11,0350
• 2001-2002 Baseline
• 2001 Canning
• 2002 Canning
•
•
•
• • •
•
•
1
• I
I
1
I
I
I
Proposed load limit
32,670 ppd (90 ppdikc�
5,000 10,000
15,000 20,000 25,000 30,000 35.000
TF Influent BOD
Table 5-5
Trickling Filter Loading Rates
Annual Average
Maximum Months
Design
Loading
Rate
Flow
Loading
Rate
Flow
Year
ppd/kcf
mgd
ppd/kcf
mgd
Current
42
9.80
90
11.25
2004
44
10.19
90
11.50
2009
48
10.79
90
11.50
2014
53
11.79
90
11.50
2019
58
12.69
90
11.75
2024
60
13.00
90
11.80
BO
60
13.30
90
12.50
'Maximum month conditions occur during Del Monte discharge.
5.4.3.4 Intermediate Degritter
Trickling Filter effluent passes through the intermediate degritter, which is fitted with
two rectangular screw grit conveyors. Flows pass through the degritter prior to returning
to the trickling filter pumping station wet well for recirculation or to the trickling filter
pump station junction box which discharges to the Aeration Basins. Surface dimensions
of the overall degritter chamber are 18'- 10" X 26'-6" equaling 4,025 cf. The chambers
are designed to remove snails from the trickling filter effluent. Currently, a significant
portion of the trickling filter effluent bypasses the degritters to discharge to the Trickling
Filter Clarifier via the trickling filter clarifier effluent pump station (formerly known as
the secondary effluent flow diversion box).
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-26
Operations and Maintenance Issues
• The current configuration of the intermediate degritter facility precludes taking
basins out of service independently of each other. This flexibility would provide
for improved maintenance and cleaning and allow operation of each basin
independently.
• Operations staff has reported a significant amount of snail shells pass through to
both the digesters and aeration basins.
Process Rating
The intermediate degritter is designed as conventional grit chamber. The basins have a
cumulative volume of 60,250 gallons. With the trickling filter pumping station operating
rates of 15.3, 27.4 and 36.0 mgd (corresponding with 1, 2 and 3 putnps in operation and
meeting full design guidelines of the trickling filter rotary distributors), the detention
times within the basins are 5.7, 3.2 and 2.4 minutes respectively. WDOE design criteria
suggest minimum detention times within grit removal facilities to be in the range of 3 to 5
minutes at peak flow conditions.
Although the peak design flow of the pumping station at 36.0 mgd (corresponding to 2.4
minutes of detention time) is slightly below the 3 minute WDOE suggested guideline, the
degritter should fall within the WDOE guidelines. Because the Trickling Filter Clarifier
is in use, not all flows from the Trickling Filters go directly to the intermediate degritter.
In the extremely rare scenario that the Trickling Filter pumping station pumps at full
capacity of 36 mgd, the degritter can accept up to 28.9 mgd to meet a 3 -minute detention
time while the Trickling Filter Clarifier accepts the rest of the flows.
5.4.3.5 Trickling Filter Clarifier
Trickling filter effluent is transferred to a 170 -foot diameter Trickling Filter Clarifier with
an 8 -foot side water depth. The clarifier is now used as part of standard operations to
settle trickling filter solids prior to entering the activated sludge process. This clarifier is
not provided with sludge drawoff pipes on the clarifier mechanism. Solids are removed
from the clarifier using a variable speed Trickling Filter Clarifier sludge pump and sent to
either the DAFT or the headworks.
Operations and Maintenance Issues
• Solids drawn from the trickling clarifier have a significant variation in
consistency. It is estimated that the sludge concentration varies from 100 to
10,000 mg/L depending on sludge rake position and the elevation of sludge in the
hopper.
Process Rating
Based upon standard design criteria, the recommended overflow rates (OFR) for this
clarifier under annual average, maximum month and peak hour conditions would be 600,
800 and 1,200 gpd/sf, respectively. Under these hydraulic loading conditions, the
clarifier capacity would be 13.6, 18.1 and 27.2 mgd respectively. Based on the flows sent
to the trickling filters, the trickling filter clarifier has sufficient capacity throughout the
design period. There is no redundancy provided with a single clarifier, although the unit
can be serviced during base load periods (no Del Monte discharge) by sending trickling
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-27
filter effluent directly to the aeration basins, as was the practice in the past. Process
modeling predicted that, if the trickling filter clarifier was out of service during current
maximum month influent loading combined with Del Monte discharge, the aeration basin
MLSS would be over 4,000 mg/L and solids loading limits on the secondary clarifiers
would be approached.
5.4.3.6 Activated Sludge System
The activated sludge system consists of four rectangular aeration basins, a low pressure
air system, two secondary clarifiers, a secondary solids pumping system, and a control
system. Effluent from the primary clarifiers and/or from the trickling filter clarifier is
directed to the aeration basin flow control structure for treatment within the activated
sludge process. The incoming flow may be mixed with the return activated sludge at this
location, or it may be mixed upon entering the aeration basins, depending upon which
treatment mode is operated within the aeration basins. Four modes of operation are
currently available at the aeration basins. These include; complete mix, plug flow, step
feed, and contact stabilization. Flow is discharged from the aeration basins into the
mixed liquor channel and proceeds to the secondary clarifiers. A piping gallery located
below the mixed liquor channel connects the RAS pumping, WAS pumping, and
Dissolved Air Floatation (DAF) thickener facilities. Flow potentially may exit from any
or all of the aeration basins, depending upon mode of operation. However, the effluent
openings for Basins 1 and 4 are blocked off and haven't been opened in years.
5.4.3.7 Aeration Basins/Low Pressure Air
Each of the four aeration basins has surface dimensions of 60 -feet X 90 -feet and a 26-
foot sidewater depth. The combined Aeration Basin volume is 4,201,000 gallons
(516,600 cubic feet). When operated in complete mix mode, the wastewater is mixed
with return activated sludge in the aeration basin control structure and distributed as
evenly as possible to each aeration basin. Experience has shown that it was difficult to
achieve an even flow split with this mode of operation.
In the plug flow mode of operation, the aeration basins are operated in series with the
flow passing from basin to basin until exiting into the mixed liquor channel from the final
basin. The return sludge mixes with the influent in the first basin. The plug flow mode
has been used with good results. The basins are currently operated in a variation of the
plug flow mode with only a small amount of air provided to the first basin, so that it acts
as an anoxic selector to reduce filamentous growth. It is also intended to consume nitrate
in the first basin and reduce aeration costs, but the current recycle flow rate is much less
than optimal.
Under the step feed mode of operation, wastewater is typically distributed to the first two
basins in series.
Under the contact stabilization mode of operation, RAS is sent to Basin 1 and influent
wastewater is fed to the second basin in series. The activated sludge then flows to the
remaining aeration basins in a plug flow configuration for further stabilization. The first
basin is maintained as the stabilization basin, and the remaining basins are the contact
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 5-28
basins. Contact stabilization has been used successfully when other modes of operation
have caused solids overload to the secondary clarifiers.
Aeration is supplied to the basins fine bubble air diffuser system via four multistage,
positive displacement blowers. The blowers have a capacity of 5,500 ICFM and 4,800
SCFM, operated from 400 Hp motors. A 12 -inch low pressure air lateral, equipped with
thermal dispersion air mass flow meter and motor actuated butterfly valve serves each of
the four aeration basins. Each 12 -inch lateral has three 8 -inch drop legs that supply air to
three separate diffusers grids. The aeration diffusers are porous ceramic disc fine bubble
units in basins No. 2, No. 3, and No. 4, and membrane fine bubble units in basin No. 1.
Each basin is provided with a dissolved oxygen probe that may be used in conjunction
with the motor actuated valve to control the flow of air to the basin.
Operations and Maintenance Issues
• An even distribution of influent wastewater between basins is not possible with
the current configuration of flow split facilities. As a result, the complete mix
mode of operation is not used. The gates/split system for complete mix needs to
be rehabilitated if this method of operation is to be continued.
• Basin configuration does not provide flexibility or provisions for basin splitting to
enable operation of aerobic/anoxic zones that would allow for nutrient removal.
• The aeration diffuser grids are located approximately 3 feet above the basin floor.
There have been problems with the stability of the diffuser grids, primarily
associated with diffuser bracing due to the height of the grids from the floor.
• Snails are continuing to be found in the aeration basins, even though considerable
amount of snails are being removed in the intermediate degritting facility and the
trickling filter clarifier. Snails are getting through to the aeration basins and are
settling to the bottom of the aeration basins.
• The current fine bubble diffuser system for basins No. 2, No. 3, and No. 4 uses
ceramic diffuser plates. Cleaning is a problem (use of acid for cleaning).
Ceramic plates allow liquid back flow into the air piping if there is a blower
failure. Many are 10 years old and need to be rehabilitated. Aeration basin No. 1
has membrane fine bubble diffusers installed.
• Certain valves are getting old and need replacement.
• The air metering systems do not record air flow accurately.
• The variable frequency drives for the blowers (Siemens) are older technology
units and require added maintenance. One of the drives is temperature sensitive.
Control cards require frequent replacement but can take up to one year to obtain.
Problems exist with isolation transformers and filters tripping out.
• When in the AUTO mode of operation, the blowers cycle. Operation staff adjusts
blower operation manually at this time to control aeration header pressure.
• The aeration basin walls are showing signs of concrete corrosion/wear at the
water surface to wall interface. Coating of the basin walls is needed.
• Operations staff noted that, if air is introduced in significant amounts in the mixed
liquor channel, better settling solids (in the settleometer) are achieved.
Operations staff have not monitored this occurrence in the secondary clarifiers.
• Alkalinity in the aeration basins has been reported as marginal.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-29
• Effluent gates in Basins 1 and 4 are sealed shut which reduces operational
flexibility.
Process Rating
The activated sludge process at Yakima currently operates in the plug flow mode with up
to four basins available for operation. During canning season, four basins are in
operation, while during the non -canning season, three basins are utilized. This capacity
evaluation anticipates that the trickling filter process would be continued, and that the
activated sludge process would operate as a complete mix system at a sludge age of 7-8
days, with the solids loading limit of 3,000 mg/L. To maximize treatment capacity, up to
four basins could be used. Operations staff has experienced problems with process upset
at MLSS values in excess of this amount
The process evaluation indicated that the aeration basins have sufficient capacity for
solids loading at a MLSS of 3,000 mg/L and maximum month loading condition. The
maximum month capacity during Del Monte discharge, when influent loading is higher,
of the aeration basins is 15.0 mgd. This capacity rating is based on four aeration basins
in-service, sufficient air supply is provided, and an oxygen uptake rate (OUR) of 52
mg/L/h is achievable. In 2018, additional aeration basin capacity is required, as
illustrated in Table 5-6 and Figure 5-7.
Table 5-6
Aeration Basin MLSS Concentrations
Annual Average
Maximum Month
Design
Flow
MLSS
Number
of Basins
Flow
MLSS
Number
of Basins
Year
mgd
mg/L
#
mgd
mg/L
#
2002
11.8
1,862
3
12.12
1,880
4
2004
12.2
1,914
3
12.52
2,068
4
2009
12.8
2,060
3
13.12
2,367
4
2014
13.8
2,208
3
14.11
2,728
4
2019
14.7
2,366
3
15.01
3,017
4
2024
16.0
2,756
3
16.30
3,441
4
BO
19.0
2,660
4
19.29
4,213
4
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-30
4,000
3,500
3,000
2,500
J
EQI
vi 2,000
1,500 -
Figure 5-7. Aeration Basin MLSS Concentration
Approximate limit for
stable operation
1,000
500
0
00 O� OrO
OC) P•4
,
`1, �O r�0 �LO
Maximum Month MLSS
New A -Basin needed
Annual Average MLSS
q5 rC)
Year
AA MLSS MM MLSS
�rO NO �O L1 ti
19' r
,LO �O (O
The aeration basins satisfy WDOE Class I and Class II requirements of having at least
two equal -volume basins installed. With the trickling filter clarifier in operation, the
aeration basins have been running at lower airflow rates due to reduced loadings to the
aeration basins. Current air flow to the aeration basins is estimated to be between 3,000
and 7,000 scfm, with one blower running most of the year and two blowers during peak
loading periods. Should one blower go out of service, three other units are available.
Therefore, the existing blowers satisfy WDOE Class I and Class II reliability
requirements. WDOE requires that the air diffuser system for each aeration basin to be
designed so that the largest section of diffusers can be isolated without measurably
impairing the oxygen transfer capability of the system. Because the aeration basins are
mixing -limited, rather than controlled by the oxygen needs to treat organic load, the
WDOE requirements are satisfied. That is to say, the dissolved oxygen concentration
will be maintained if the largest diffuser section is removed from service, because
aeration will continue to be provided to maintain solids suspension, which is projected to
be over and above the aeration needed for organic load treatment.
Future maximum month aeration requirements are estimated at 10,530 scfm in 2024. The
blowers have a firm capacity of 14,400 scfm (with one blower not in service). Therefore,
the blowers have sufficient capacity for 2024 conditions. However, because of ongoing
problems with the blowers and VFDs, blower replacement options are evaluated and
presented in Section 6.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-31
Flow and loadings exceed the current aeration basin capacity limit during the Del Monte
critical design month if the trickling filter process were to be discontinued.
5.4.3.8 Secondary Clarifiers
Mixed liquor exits the Aeration Basins into two 140 -foot circular Secondary Clarifiers.
Each clarifier operates at a 15 -foot sidewater depth. Wastewater enters the clarifiers
through a center feed well and overflows into an inboard (interior) launder.
Operations and Maintenance Issues
• Cleaning the secondary clarifiers remains a problem. Chlorine control systems
installed along the launders require additional improvement. Plant staff would
like to consider a brush cleaning system or launder covers.
• The baffles on the secondary clarifiers collect solids (accumulating algae) which
are difficult to remove.
• The inboard launders, which are rusted and have many holes, are suspected to
impact secondary clarifier performance. The launders need to be moved to the
outside edge of the basins.
• Secondary clarifier bull -gears:
o Grit was found in the gear housings.
o Gear assemblies were installed in 1983 and may require replacement.
• Secondary clarifier launder accessibility should be improved (exterior launders
and fiberglass weirs).
• The secondary clarifier skimmer mechanisms may require improvements. The
spray bar is too high and needs to be optimized. Plant staff expressed interest in
having ducking skimmers.
• The secondary scum boxes are too small and should be enlarged.
• Location of any new secondary clarifiers on-site will be a major issue.
o Impact on existing power lines.
o Flow split to existing and new secondary clarifiers will be difficult.
o Impacts from the old lagoons need to be evaluated when selecting a site
for new clarifiers.
Process Rating
The SOR of the secondary clarifiers is presently at 390 gpd/sf under average flow
conditions, and 780 gpd/sf under peak hour flow conditions. This is well within the
WDOE design criteria of 600-800 gpd/sf for average conditions and 1,200 gpd/sf for
peak flow conditions.
The clarifiers were evaluated based on Class II reliability requirements as this is the
designated classification for the WWTP. Class I reliability requirements were evaluated
for comparison purposes.
The reliability standards for WDOE Class I require that the final sedimentation system be
able to handle 75 percent of the design flows with one unit off-line. The reliability
standards for WDOE Class II require that the final sedimentation system be able to
handle 50 percent of the design flows with one unit off-line. The annual average and
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 5-32
WDOE overflow rates are shown in Table 5-7. Applying the above loading criteria to the
facility, the treatment capacity of one secondary clarifier is calculated as follows:
• Applying 600 gpd/sf under average flow conditions with one unit off-line, the
reliable treatment capacity is 9.2 mgd. This would represent 75 percent of an
annual average flow of 12.3 mgd. Current annual average flow is 11.79 mgd.
• Under peak hour conditions and an OFR of 1,200 gpd/sf, the treatment capacity of
one clarifier is 18.5 mgd. This would represent 75 percent of a peak hour flow of
24.6 mgd. Current peak hour flow is 24.0 mgd.
Table 5-7
Secondary Clarifier Overflow Rates
WDOE Requirements
WDOE Requirements
Class I
Class II
2 Basins in Service
1 Basin in Service
1 Basin in Service
Design
Flow
Overflow
rate
75% of
Flow
Overflow
rate
50% of
Flow
Overflow
rate
Year
mgd
gpd/sf
Mgd
gpd/sf
mgd
gpd/sf
2002
11.79
383
8.8
574
5.9
383
2004
12.19
396
9.1
594
6.1
396
2009
12.79
415
9.6
623'
6.4
415
2014
13.79
448
10.3
672
6.9
448
2019
14.69
477
11.0
716
7.3
477
2024
15.98
519
12.0
779
8.0
519
BO
18.97
616
14.2
924
9.5
6162
i An additional clarifier will be needed prior to 2009 to meet Class I criteria, based on
limiting the average overflow rate to 600 gpd/sf.
2 An additional clarifier will be needed prior to Buildout to meet Class II criteria,
based on limiting the average overflow rate to 600 gpd/sf.
Based upon the above, the secondary clarifiers are near hydraulic capacity for WDOE
Class I redundancy requirements. For Class II redundancy requirements, additional
secondary clarifier capacity is required prior to buildout.
Evaluation of the secondary clarifiers for solids loading rate (SLR) indicate solids loading
of the clarifiers is not the limiting criteria when looking at WDOE Class I requirements,
as shown in Table 5-8. Based upon an SLR of 24 lb/d/sf for average conditions and 30
lb/d/sf for maximum month conditions, the capacity of the clarifiers is 15.98 and 16.3
mgd respectively. These values are slightly in excess of the hydraulic limits stated above.
Hydraulic capacity of the secondary clarifiers, based upon an HRT of 2 hours, is 31.4
mgd at peak flow conditions. When looking at WDOE Class II requirements, additional
secondary clarifier capacity is required prior to buildout in order to maintain both
hydraulic limits as well as and SLR of 24 lb/d/sf for average conditions and 30 lb/d/sf for
maximum month conditions.
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 5-33
Table 5-8
Secondary Clarifier Solids Loading Rates
Annual Average
Maximum Month
Design
Loading
Rate
Flow
Loading
Rate
Flow
Year
ppd/sf
mgd
ppd/sf
mgd
2002
12
11.79
17
12.12
2004
13
12.19
18
12.52
2009
14
12.79
19
13.12
2014
16
13.79
21
14.11
2019
19
14.69
25
15.01
2024
24
15.98
30
16.30
BO
27
18.97
44
19.29
Based upon the increase in flows and loads projected in Section 4, additional secondary
clarifier capacity is needed prior to year 2009 to meet WDOE Class 1 redundancy criteria,
and prior to buildout to meet Class II redundancy criteria. As discussed in Section
5.4.3.5, there is no redundant trickling filter clarifier. If the trickling filter clarifier is out
of service during peak loading conditions, the aeration basin MLSS will be over 4,000
mg/L and the solids loading limit on the secondary clarifiers would be approached. To
alleviate this potential situation, it is recommended that an additional secondary clarifier
be constructed. Construction of a new secondary clarifier is favored over a new trickling
filter clarifier, because a new secondary clarifier would be advantageous during the entire
year, whereas the trickling filter clarifier is needed mainly during canning season loading.
During further design efforts, construction of this clarifier with the capability to operate
as both an intermediate trickling filter clarifier or a secondary clarifier should be
investigated.
5.4.3.9 RAS Pumping
Return activated sludge is transferred from the secondary clarifiers back to the aeration
basin flow control structure through 2 screw pumps. Each of the 24 -inch RAS lines
leaving the secondary clarifiers is fitted with a flow control system consisting of a
modulating knife gate RAS control valve and a flow meter. Flow is lifted by the RAS
pumps and discharged into a discharge structure. From this location, RAS flow can be
directed to either aeration basin No. 1, or to the aeration basin flow control structure.
RAS pumping is operated in either constant flow or as a percent of influent flow. Typical
operation is on a percentage of 50-60 percent of influent flow.
Operations and Maintenance Issues
• RAS Screw Pumps:
o An access manhole for maintenance of the lower bearings is needed.
o Wear on the concrete channel of the inclined screws is moderate.
Regrouting of the incline channel is recommended if the RAS screw
pumps remain in operation.
o The isolation gates for the screw pumps are in need of re -working.
o Screw pumps are old and the bottom bearings are wearing out.
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 5-34
o Spare parts for the screw pumps are not readily available.
o On both screw pumps, a new gearbox is needed.
• The RAS flow control facilities have very poor resolution at low flow rates. The
turn down rate is not low enough for low flows (i.e. 50% of average daily flow
conditions). Operations staff cannot turn down the flow control any lower than
approximately 3 mgd per clarifier. This is a limitation of the knife gate valve and
gravity flow arrangement for return control without plugging of conveyance
piping.
Process Rating
Each RAS pump has a firm capacity of 13,500 gpm (19.4mgd), powered by a 40 HP
motor. WDOE class I and II reliability standards requires that one pump serve as the
backup to the other unit. Based upon an expected return rate of 60 percent of influent
flow, the RAS pumping station, with one pumping unit in service, can maintain sufficient
return flows for an influent flow of up to 32.4 mgd. Sufficient capacity is available at the
RAS pumping station to serve current annual average and peak hour flow conditions.
Limitation on flow control at lower flow rates appears to be problematic to operations.
Sufficient RAS pumping capacity is available to handle the projected annual average
flow for year 2024 of 15.5 mgd. The pumping facilities do not have sufficient capacity to
handle the 2024 peak hour condition of 32.9 mgd. However, only a slight compromise in
return rates is necessary to meet this flow condition.
5.4.3.10 WAS and Secondary Scum Pumping
Waste activated sludge and secondary scum are pumped from the secondary clarifiers
through two separate pumping systems. WAS can be drawn from the RAS wet well via
two 10 HP, 800 gpm, variable speed, VFD controlled centrifugal pumps. Secondary
scum is pumped via 2 air -diaphragm pumps, each with a capacity of approximately 50
gpm as installed. The air diaphragm pumps can also be used for pumping WAS, by
drawing clarifier bottom sludge via a 6 -inch line. Both systems may serve as redundant
to each other. The magnetic flow meter located on the discharge side of the centrifugal
pumps sets the secondary wasting, controlled from either a speed control or time control
mode of operation.
Operations and Maintenance Issues
• Through the use of a three-way valve, the air diaphragm pumps can switch
between pumping secondary scum and clarifier bottom sludge. Plant staff prefers
having designated suction piping and valves for each of these functions. In
addition, the 25 -year-old air -diaphragm pumps should be replaced.
Process Rating
Each 800 gpm WAS pump will more than meet future solid flows, estimated to be 82 and
146 gpm at 2024 annual average and maximum month conditions.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-35
5.4.4 Final Disinfection
The final disinfection evaluation includes assessment of condition and capacity of the
chlorination mixing chamber, chlorine contact chamber, and chlorination and
dechlorination facilities.
5.4.4.1 Chlorination Mixing
Secondary effluent flows into the chlorine mixing chamber where chlorine solution is
introduced through a chlorine induction unit or a direct gas feed system. A 15 HP
vertical turbine flash mixer helps mix and distribute the disinfectant to the treated
wastewater. The mixing tank volume is 13,470 gallons.
5.4.4.2 Chlorine Contact Chamber
Two 120 -feet X 30 -feet rectangular chlorine contact chambers are utilized to allow
proper disinfection of the plant effluent. The combined basins contain 808,000 gallons at
a sidewater depth of 15 -feet. Final effluent flows into a concrete channel, located at the
east end of the chambers, and out a 60 -inch effluent pipe. Scum is collected with a 16 -
inch scum skimmer and sent to the plant sanitary sewer system.
5.4.4.3 Chlorination Facilities
The chlorination building is located north of the chlorine contact chamber. The facility
has three rooms, including a chlorine storage room, chlorinator room, and pump room.
Three large chlorinators are positioned in the chlorine room and utilized to distribute
chlorine solution throughout the plant, two for disinfection, and one unit for support of
the odor control system. Each chlorinator has an individual capacity of 500 to 2000
Ib/day depending on rotameter size installed. Current installed rotameters allow
individual feed capacities of 500, 1000, and 2000 Ib/day for the three chlorinators. The
facility maintains three active, and three standby, 2000 pound chlorine gas cylinders. In
addition to the three large chlorinators, two smaller unit chlorinators are located in the
chlorine room for disinfection of non -potable (C2) water used throughout the plant site.
Normal usage of chlorine at the Yakima Regional WWTP is 200 to 300 lbs/day.
5.4.4.4 Dechlorination Facilities
The Dechlorination Building is located directly north of the Chlorination Facility and is
divided into four rooms including the Sulfur Dioxide (SO2) Feed Room, the SO2 Storage
Room, the Chemical Storage Room, and the Motor Control Center (MCC) Room. The
Chemical Storage room houses foul air scrubber feed pumps, odor scrubber recirculation
pumps, and the chemical recirculation pump. Dechlorination is provided by 2 sulfanators
located in the SO2 Feed Room, each with a capacity of up to 475 lb/day. Sulfur dioxide
cylinders are stored and accessed from the SO2 Storage Room. Typically, two 2000 lb
cylinder are active. 502 is injected into the plant effluent at the Chlorine Contact
Chamber outlet pipe and samples are extracted from the Outfall Connection box. Normal
usage of sulfur dioxide at the Yakima Regional WWTP is 40 to 50 lbs/day.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-36
Operations and Maintenance Issues
• Safety issues have been associated with the gas Chlorine/S02 feed systems. An
alternative disinfection process should be considered in lieu of continuing use of
the gas systems.
• By-products (Salmon Impacts) of the chemical addition for chlorination and
dechlorination are a concern on the impacts to aquatic life.
• Plant staff would like to have two additional scales for the third chlorine tank.
• Chlorine and sulfur dioxide analyzers are outdated. Sulfur dioxide analyzers do
not work in automatic mode and feed is a manual operation.
• The chlorination system is not sensitive enough to trim back during periods of
low flow without changing rotameters.
Process Rating
With three active 2,000 lb cylinders, the chlorination system firm capacity is 1,200 lbs/d.
This is based upon the maximum allowable feed rate of 400 lbs/day from each active
cylinder per WDOE criteria. With two chlorinators dedicated to effluent chlorination, the
firm capacity of the chlorination system is 1500 lbs/d. In accordance with the WDOE
design guidelines, the recommended dosing capacity for activated sludge wastewater
effluent is 2- 8 mg/L. At the peak hour flow condition of 24.0 mgd, a dosage of 5 mg/L
is provided, within the recommended range for dosage.
WDOE requires a one-hour retention time in the chlorine contact chamber at average
flow and 20 minutes at peak flow conditions. The capacity of the contact chamber at
average conditions is 19.4 mgd. At peak flow conditions, the estimated capacity of the
chlorine contact chamber is 58.2 mgd, well in excess of design criteria for peak flow
conditions.
Based upon projected flows and loadings presented in Section 4, the contact channel has
sufficient capacity to the year 2024 average annual flow conditions of 15.5 mgd and year
2024 peak flow conditions of 32.9 mgd. Therefore, the basin has sufficient capacity to
meet the retention time requirements at the projected flow rates.
5.4.5 Outfall and Outlet Box Facilities
Treated and disinfected wastewater flows into an outfall connection box southeast of the
trickling filter clarifier. Flow exits the outfall connection box through a 78 -inch pipe and
into the outfall structure. The outfall structure contains two chambers with a weir wall
and manual sluice gate as isolation. Effluent typically flows through the gate in the weir
wall into the second chamber and out two 30 -inch discharge pipes. Flow may also
bypass the discharge piping through a 36 -inch x 48 -inch motor operated sluice gate into a
bed of quarry rock above the Yakima River high water level. The two 30 -inch outlet
pipes reduce to 24 -inch where the concrete encasement begins. At the assimilation point
in the Yakima River, the pipes are tapered and flow is directed downstream into the river
at a vertical angle of 15 percent and a 45 degree horizontal angle to river flow direction.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-37
Operations and Maintenance Issues
• The sluice gate in the weir wall of the outfall structure does not work and is
permanently open. The gate should be fixed so that it can be closed and the weir
can be used.
Process Rating
The capacity of the existing outfall and outlet box facilities is estimated to be in excess of
45.0 mgd at river elevations below the 100 year flood level. This is based upon the
secondary clarifier effluent launder troughs not surcharging the secondary clarifier weirs.
The capacity of the outfall system exceeds the estimated peak hour flow conditions for
year 2024 even when the Yakima River is at the 100 year flood level. At the 100 year
flood level, the capacity of the outfall system is estimated at 34.7 mgd without
submerging the secondary clarifier weirs.
5.4.6 Non -Potable Water System
Plant effluent is utilized for both irrigation and non -potable (C2) water. The irrigation
system is supplied from the existing C2 System. Non -potable water is pumped from the
Chlorine Contact Chamber channels with two higher volume vertical turbine pumps and
from a sump beneath the pump room with three smaller capacity vertical turbine pumps.
Pump capacities are two 60 HP units rated at 1,200 gpm at 145 feet TDH and three 25 HP
units rated at 500 gpm at 145 feet TDH. Pumped C2 water combines and enters the
Chlorination Building where it flows through automatic strainers then out to the plant
system. Two booster pumps, operating at 60 gpm and 85 ft TDH with 3 HP motors,
supply C2 water to the chlorination system for additional chlorination of the C2 water
supply.
Operations and Maintenance Issues
• The larger volume vertical turbine pumps are installed in the chlorine contact
channels in a location where the flows pumped are taken from a point at
approximately halfway through the contact channel. This is due to the location of
the divider baffle walls and the pump inlet location. As a result, the contact time
provided for the C2 flows from the larger volume pumps is (on occasion) less
than the recommended design criteria for contact time
• Sufficient pressure and water volume is provided throughout the plant from the
C2 utility.
• Some of the older hydrants are operating at low water pressures. These are likely
older hydrants served by small diameter laterals.
5.4.7 Solids Thickening
The solids thickening evaluation includes assessment of condition and capacity of the
dissolved air floatation thickener (DAFT). Solids from the secondary processes are sent
to a single 45 -foot diameter dissolved air flotation thickener for thickening. WAS from
the secondary clarifiers is combined with trickling filter sludge from the intermediate
clarifier and pumped to the DAFT tank. Thickened solids from the DAFT process are
pumped to the anaerobic digesters using two air -diaphragm pumps. The DAFT is
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-38
operated approximately 12 hours per day, 7 days per week. According to plant staff,
polymer is occasionally used for DAFT thickening; however, the DAFT uses the same
polymer feed system that is used for centrifuge dewatering. Consequently, polymer can
not be fed to the DAFT when the centrifuge is in operation. The Solids Building houses
the recycle pumps, TWAS pumps, saturation tank, and two air compressors that support
the DAFT process. The DAFT and Solids Building are situated at the west end of the
aeration basins.
Operations and Maintenance Issues
• The DAFT unit has been reliable, but the system is reaching the end of its service
life, needs rehabilitation, and has no redundant unit.
• The support air compressors, originally installed in 1985, are in need of
replacement.
• The air line supply to the pressurization tank is black iron, shows a significant
amount of corrosion, and should be replaced. Replacement of the line with
stainless steel is preferred.
• The DAFT tank cannot be drained completely with the drainage piping currently
installed.
• Additional C2 water capacity should be located next to the DAFT to better enable
washdown activities at the DAFT unit.
Process Rating
The existing DAFT unit was rated by the manufacturer to support a 1.0 lb/hr/sf solids
loading rate (SLR). This SLR is typical for DAFT treatment of WAS with polymer
addition. Typical SLRs for DAFT treatment without polymer addition decrease to
approximately 0.4 lb/hr/sf. The hydraulic loading rate (HLR) of DAFT units is usually
limited to a maximum of 2.5 gpm/sf.
Plant data for annual average and maximum month solids production from 2002 through
September 2003 are presented in Table 5-9. The WAS solids quantities from June 2002
through June 2003 include approximately 50 percent of the trickling filter solids removed
through the intermediate clarifier. The calculated DAFT SLRs at current average and
maximum month conditions are also listed in Table 5-9. These SLRs indicate that the
DAFT is reaching its theoretical capacity for treatment without polymer addition (0.4
lb/hr/sf), based on a 12 hour operating schedule. However, the capacity can be expanded
by increasing the operating schedule or through polymer addition.
Future 2024 solids quantities to the DAFT unit are also listed in Table 5-9. These solids
quantities are based on the values presented in Table 5-2 and reflect 100 percent of the
trickling filter solids thickened through the DAFT. Based on the solids quantities and
DAFT loading rates presented in Table 5-9, the existing DAFT has adequate capacity to
thicken all WAS and trickling filter solids generated in 2024 if the DAFT is operated on a
24 hour, 7 day basis. At 2024 average annual flow conditions, the DAFT can support 12
hour, 7 day operation, but will require polymer addition since the loading rate will exceed
0.4 ppd/sf. If the DAFT operating schedule is increased to 24 hours per day, polymer
addition may be avoided, reducing chemical costs. A 24 hour DAFT operation will also
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-39
reduce slug loadings on the downstream digesters, minimizing potential for foaming and
upset.
Table 5-9
Current DAFT Loading and Theoretical Capacity
Combined WAS and
Trickling Filter Solids
(pp d)
SLR'
(lb/lir/0')
Current Operation
Annual Average
7,7003
0.4
0.5
Maximum Month
8,900
2024 Operation with TF solids
Annual Average
17,000
0.9
Annual Average (24 hour)
17,000
0.4
Maximum Month
25,000
1.34
Maximum Month (24 hour)
25,000
0.7
Theoretical DAFT Capacity
Without polymer addition
8,000
0.4
Without polymer addition (24 hour)
16,000
0.4
With polymer addition
19,000
1.0
With polymer addition (24 hour)
38,000
1.0
1SLR based on 12 hr/day, 7 day/week operating schedule, unless otherwise noted.
2Assumes 100 percent of trickling filter solids are thickened through DAFT.
3Current quantities do not always include trickling filter solids.
`Exceeds recommended SLR.
While the existing DAFT can support the projected 2024 solids loading, the current
equipment provides no redundancy. Therefore, a second 45 -foot DAFT is recommended
to provide backup. The operation of the DAFT units should be cycled to ensure that all
equipment stays in working order.
5.4.8 Anaerobic Digestion
The solids digestion evaluation includes assessment of condition and capacity of the
primary and secondary digesters. Anaerobic digestion is performed in three primary
digestion tanks and three secondary tanks. Tank dimensions and volumes are listed in
Table 5-10. The primary digesters are equipped with fixed, concrete covers and are
mixed with turbine mixers. Hot water/sludge spiral heat exchangers are used to heat the
primary digesters. All three secondary digesters are equipped with membrane gas holder
covers that provide gas storage for the digester system. Digester gas is used to fuel a
boiler, which provides hot water for digester heating and plant building heat. Digester
gas in excess of the boiler fuel requirements is flared.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-40
Table 5-10
Existing Digester Tankage
Diameter
(feet)
No. of
Tanks
Volume, each
(MG)
Volume, Total
(MG)
Primary Digestion
70
1
1.0
1.0
45
2
0.33
0.7
1.7
Secondary Digestion
40
3
0.22
0.7
Operations and Maintenance Issues
• Flow meters on each recirculation line would be desirable for improved operation.
• Piping connections could be added to the digester piping to allow for vactor
pumping of the digester contents via the piping arrangement in lieu of through the
digester access hatches.
• Only a single recirculation pump is available to serve all three secondary
digesters. A more dependable or appropriate pump or pumps should be
evaluated.
• The waste gas flare needs a new control valve. Operation currently complies with
air quality permitting.
• Gas production is not being accurately measured. Gas flow meters should be re-
calibrated and gas lines should be inspected for leaks.
• Gas piping may have significant dips and fouling, increasing the piping capacity
would immediately increase the capacity of the boilers (they are gas -limited).
• Plant staff would like to install a grease receiving facility to treat and send grease
to the primary digesters. The facility would be adjacent to the primary digesters.
• Access to the piping valve trench in the primary digester building is difficult.
Replacement of the access cover with a new lighter weight cover system is
desired.
• Better lighting is required in the primary digester building. Currently it is very
difficult to replace bulbs.
Process Rating
Digester feed consists of primary solids, WAS, and trickling filter solids. Plant data from
2002 through 2003 indicate that primary clarifier solids and DAFT solids are fed to the
digester at a concentration of 4.6 percent and 3.5 percent, respectively. Currently,
trickling filter solids are thickened through the primary clarifiers (via conveyance to the
headworks) or the DAFT. Depending on the split of trickling filter solids to the primary
clarifiers or the DAFT, the combined feed solids to the digester can range from 3.9 to 4.3
percent solids. Digester capacity calculations were performed using a combined solids
concentration of 4.1 percent, based on splitting the trickling filter solids equally between
the primary clarifier and the DAFT.
Digester solids retention times are presented in Table 5-11. Based on the projected solids
quantities for 2004, the existing digester tankage provides a 27 day SRT at AA conditions
and an 18 day SRT at MM with all primary tanks in service. Based on CFR 40 Part 503
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-41
time/temperature criteria for Class B solids, the existing digester tankage can meet the 15
day MM requirements through 2015. At 2024 MM conditions, the existing digesters
provide only 13 days of detention. In addition, since digester tankage should be taken out
of service for cleaning every five to ten years, digester design typically assumes that
secondary digester volume can be used for primary digestion detention when a primary
digester is out of service. If the 70 ft diameter primary digester, which provides 1.0 MG
of digestion, is taken out of service, the SRT in the remaining primary tanks decreases to
11 days and 7 days, at 2004 AA and MM conditions, respectively. Even if the secondary
digesters, which total 0.7 MG, are used to back up primary digestion, the tankage can not
completely support the 15 -day primary digestion requirement. Therefore, it is
recommended that enough primary digester tankage be installed in the future to not only
support the additional capacity required in 2024, but to also ensure that if the existing 70
ft diameter digester is out of service, that the primary and secondary digesters can safely
meet Class B detention requirements. This requires a new 0.6 MG primary digester if the
secondary digesters are retrofitted to operate as primary digesters, or a 1.3 MG primary
digester with out retrofitting the secondary digesters.
Table 5-11
Existing Digester Tankage Capacity
2004
2024
Average
Annual
Maximum
Month
Average
Annual
Maximum
Month
WAS, ppd
5,500
7,400
7,500
13,000
Primary solids, ppd
9,100
12,500
13,000
19,000
Trickling Filter solids, ppd
6,300
11,200
9,500
12,000
Total Solids, ppd
20,900
31,100
30,000
44,000
Combined Solids, %'
4.1
4.1
4.1
4.1
Total Solids, gpd
61,100
91,000
88,000
129,000
Primary HRT, days
27
18
19
132
Secondary HRT, days
11
7
7
5
`Solids concentration based on treating 50 percent of the trickling filter solids through the DAFT
and 50 percent through the primary clarifier.
2Primary digester capacity does not provide 15 day detention to meet 40 CFR Part 503
requirements for Class B solids.
Plant data indicate that the digester feed has an average volatile solids content of 86
percent. The digesters are achieving approximately 60 percent volatile solids reduction,
resulting in a 52 percent total solids reduction. Digester feed solids average 4.1 percent
TS, with average digested sludge solids of 2.0 percent. Plant data for digester gas
production was not available, due to problems with the installed gas flow meters;
however, based on the measured volatile solids reduction, one would expect an average
gas production rate of 126,000 cfd, based on projected 2004 average solids quantities and
a digester gas production rate of 12 cf/lb VS destroyed. Plant data suggest that a lower
gas production rate has been measured; however, this is typically a result of gas meter
calibration issues or leaks in the gas piping, rather than lower than normal gas production
rates.
City of Yakima Wastewater Facility Plan -- DRAFT 8/12/05 Page 5-42
Options for Class A digestion are discussed in Section 9, as well as costs for additional
mesophilic digestion to continue to meet Class B criteria through 2024.
5.4.9 Solids Dewatering
The solids dewatering evaluation includes assessment of condition and capacity of the
centrifuges, solids handling building, and supernatant lagoon.
5.4.9.1 Centrifuges
Digested solids are dewatered using a Sharples DS -705 high solids machine. The
machine was installed in 1992 and has a rated capacity of 240 gpm. During the 2002 —
2003 period, the centrifuge produced cake with average solids concentrations of 18 to 21
percent TS. A second centrifuge is installed in the solids dewatering building, but is no
longer in service. Centrifuge feed is provided by one of two variable speed progressive
cavity pumps, each rated at 300 gpm. All solids pass through a grinder prior to centrifuge
dewatering. Dewatered solids are conveyed to the outdoor truck load out facility using a
series of screw conveyors. A small storage hopper provides approximately 20 minutes
storage prior to load out. Centrate is drained to a centrate well, which is then pumped to
the south lagoon prior to return to the head of the plant.
Based on plant staff operating experience, the centrifuge is operated 24 hours per day, 1.5
to 2 days per week. The dry polymer feed system for the dewatering operation also
supplies polymer to the DAFT system and can not feed both solids processes
concurrently. Plant data indicate that the dewatering polymer dosage averages 28 lb/dt of
solids.
Process Rating
The single DS -705 centrifuge at Yakima is rated at 240 gpm of digested solids. It has
historically produced a cake of 17 to 18 percent solids, but cake solids have increased to
approximately 21 percent in 2003. By operating two to three days per week, 24 hours per
day, the centrifuge has been able to meet all dewatering requirements at current solids
production rates. The centrifuge has adequate capacity to support the projected
maximum month solids production in 2024.
5.4.9.2 Solids Handling Building
The Solids Handling Building is located west of the DAFT and houses the centrifuges,
centrifuge feed pumps, DAFT mechanical equipment, and the polymer feed system.
Truck load out is performed in an unenclosed area immediately west of the centrifuge
area. The building has inadequate ventilation. The polymer system has polymer feed
pumps and a single mix tank, feed tank, and polymer transfer putnp.
5.4.9.3 Lagoons
Two lagoons previously existed along the south perimeter of the treatment facility. The
north lagoon has been decommissioned. The remaining lagoon has bottom dimensions of
157 ft by 407 ft with a 3:1 side slope and 15 ft sidewater depth. The total capacity of the
lagoon is approximately 10 MG.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-43
The north lagoon has been permanently taken out of service and the north lagoon area is
slated to be used for construction. The south lagoon is currently being used for
temporary storage of centrifuge centrate, prior to its return to the head of the plant.
Based on the current centrifuge operation of two to three days per week, large quantities
of centrate are produced in a relatively short time. Typically, centrifuges are operated on
a five- to seven-day schedule, which minimizes the impact of centrate return on the liquid
stream treatment processes. At the Yakima Regional WWTP, the south lagoon equalizes
the centrate, allowing it to be returned to the head of the plant at a lower, more constant
rate. If the centrifuges continue to be operated a few days per week, the south lagoon
should continue to be used for centrate equalization. If the south lagoon is taken out of
service, the centrifuge may be required to be operated for a longer period at a lower feed
rate, reducing the rate of centrate production and its subsequent impact on the liquid
stream processes. Centrate handling is further discussed in Section 9.
Safety, Reliability and Staff Issues
• There is no redundant unit with the single dewatering centrifuge.
• The dewatered cake screw conveyors are difficult to access for maintenance and
also offer no redundancy.
• A single polymer system is available for both thickening and dewatering and can
not be used simultaneously on both treatment processes. It is only capable of
accepting dry polymer handled in bags.
• The lagoons were alleged as possible sources of odor through ammonia release.
5.4.10 Miscellaneous Systems/Facilities
The following section presents an assessment of the air emissions control system,
electrical system, administration building, and accessory buildings.
5.4.10.1 Air Emissions Control System
The Yakima Regional WWTP currently controls air emissions from the Headworks
Building, Influent Building, Trickling Filters, Trickling Filter Pumping Station wetwell,
and Solids Building. The air emissions control system includes collection of air from the
various sources throughout the plant, transport of the air emissions in fiberglass ducts to
the two 170 foot diameter trickling filter domes for initial treatment, and further treatment
of the air emissions at two packed tower wet scrubbers located adjacent to the trickling
filters.
The two packed tower wet scrubbers and ancillary equipment were installed and started
up in 1992. The system operates by passing air from trickling filters upward through a
bed of packing media while a chemical scrubbing solution is sprayed over the media
counter current to the flow of air. As the air is moved through the media, the chemical
compounds which may cause air emissions react with the scrubbing solution, and any
odors in the air are oxidized. The scrubbing solution consists of hypochlorite and sodium
hydroxide (also called caustic or caustic soda). The hypochlorite is a 12 per cent solution
and the caustic soda is either a 25 percent or 50 percent solution. Both solutions are
available from chemical suppliers. The chemistry involved with the packed tower control
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 5-44
system is the oxidation of air emissions by the addition of hypochlorite. This reaction
generates hydrogen ions which lowers the pH of the solution. Caustic soda is added to
neutralize the hydrogen ions and maintain a high pH.
Chemical feed is controlled by pH and oxidation reduction potential (ORP) controllers.
As the pH of the scrubbing solution in the packed tower sump drops below the set -point,
caustic soda will be added. As the ORP of the scrubbing solution drops, hypochlorite
solution will be added. The oxidation of air emissions is a function of both ORP and pH.
The set -points on the ORP and pH controllers can be changed to suit the specific
requirements of the air emissions.
Operations and Maintenance Issues
• The pH and ORP meters are calibrated weekly and show very little drift between
calibrations. The hypochlorite tank is in deteriorating condition and needs re -
coating. The automatic level monitoring system does not work with the current
chemical. A manual system is used. The hypochlorite feed pumps are the
constant speed diaphragm type with a manually adjustable stroke length typically
set at 5 percent.
• Other than chemical corrosion, there are no major maintenance problems.
Lighting, HVAC, and safety provisions in the chemical room are adequate.
Hypochlorite consumption is approximately three to four deliveries per year or
9,600 gallons.
• The system is functioning adequately and is effectively treating air emissions.
5.4.10.2 Administration Building
The administration building is located in the northwest corner of the plant site. The
facility houses several offices, lockers and showers, a lunch/conference room, and the
laboratory. It also serves as a storage area for lab and office materials.
Operations and Maintenance Issues
• Reevaluation of space requirements is needed in the Administration Building.
The needs of the pre-treatment program, strong waste testing, priority pollutant
testing, and metals testing, will dictate the need for additional lab space.
• Some offices have been moved in the Administration Building. There is interest
in adding offices on the west side of the lunch room.
• There is a shortage of lockers in the Administration Building. Consider
expansion of the locker area to the west.
• A backflow preventer is needed for the lab water supply in the Administration
Building.
5.4.10.3 Accessory Buildings
Accessory buildings include one garage, one office, and one workshop located west of
the primary and secondary digesters.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-45
Operations and Maintenance Issues
• There is a need for additional storage for covering miscellaneous vehicles (tractor,
etc.).
• There is a need for adding truck storage (heated) for the solids hauling vehicles.
• Partial structures are needed at all composite sampler locations for protection
from weather (hot and cold). Partial enclosures large enough for operators to
stand up in would be preferred.
5.5 Summary
The organic treatment capacity of the Yakima Regional WWTP is 53,400 ppd of total
influent BOD corresponding to flows of 14 mgd during peak loading conditions
associated with the canning season. Based on projected future loads, the aeration basins
will need to be expanded in 2018 for adequate treatment of maximum loads during
canning season. The organic capacity of the WWTP during annual average conditions
and no canning loads is 21.5 mgd which will provide sufficient capacity to meet buildout
conditions with no canning loads.
At maximum month non -canning load influent characteristics, the capacity of the WWTP
is projected to be 20.2 mgd. For permitted facility loading, the following values should
be incorporated:
• Average flow (max. month) 20.2 mgd
• BOD5 loading (max. month) 53,400 ppd
• TSS loading (max. month) 38,600 ppd
• Design population 130,000
Table 5-12 summarizes the capacity rating evaluation of each unit process at the Yakima
Regional WWTP, setting capacity at the most restrictive design criteria. The overall peak
hydraulic capacity through the plant based on process limitations and connecting
conveyance structures is approximately 32 ingd. At this flow, the minimum hydraulic
retention time of the existing secondary clarifiers is reached, and successful operation of
the flow diversions at the trickling filter pump station is challenged. The table identifies
capacity of current facilities and required capacity at year 2024 projected loading
conditions.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 5-46
Table 5-12
Summary of Unit Process Capacity
Firm Capacity
Year 2024 Flow/Load
Unit Process
Units
Average'
Maximum2
Month
Peak3
Hour
Average
Maximum
Month
Peak
Hour
Comment
Bar Screens and
Screenings Compactor
mgd
-
-
40
15.5
22.2
32.9
Sufficient capacity
Grit Removal
mgd
-
-
40
15.5
22.2
32.9
Sufficient capacity
Flow Measurement
mgd
-
-
60
15.5
22.2
32.9
Sufficient capacity
Primary Clarifiers
mgd
30.5
63.6
15.5
22.2
32.9
Sufficient capacity
Trickling Filters Pumping
Station
mgd
-
-
36
15.5
22.2
32.9
Sufficient capacity at future
flows. Not all peak flow
directed to units
Trickling Filters
mgd
-
11.84
(5.9 each)
-
13.0
11.8
-
Sufficient capacity at
current and future flows
Flows over 11.8 mgd
routed to aeration basins
Aeration Basins
mgd
-
15.0'
-
16.0
16.3
-
_
Sufficient capacity at
current flows Insufficient
capacity for future
conditions after 2018
Aeration Blowers
Scfm
-
-
14,400
-
9,500
-
Blowers have sufficient
capacity for 2024 However,
ongoing problems with
blowers and VFDs limit
their reliability
Secondary Clarifiers5
mgd
9.2
(18.4
total)
-
18.5
(37
total)
16.0
16.3
32.9-
Sufficient redundancy for
WDOE Class II
requirements but high
solids loading with trickling
filter clarifier off line
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05
Page 5-47
Table 5-12
Summary of Unit Process Capacity
Firm Capacity
Year 2024 Flow/Load
Unit Process
Units
Average'
Maximum`
Month
Peak3
Hour
Average
Maximum
Month
Peak
Hour
Comment
RAS Pumping
mgd
-
-
32.4
(at 60%
recycle)
-
-
32.9
Sufficient capacity for
current peak -hour flows
Insufficient capacity for
future flow peak hour
conditions at 60% recycle
flow
WAS Pumping
gpm
-
-
800
82
146
-
Sufficient capacity Pumps
too large for WAS flows
Chlorine Contact
Chamber
mgd
19.4
-
58.2
15.5
-
32.9
Sufficient capacity for
current flow conditions
Insufficient capacity to
meet year 2024 maximum
month conditions
Chlorination Facilities
lb Ch/d
-
-
1,000
-
-
1,024
Sufficient capacity for
current and 2024 peak flow
conditions
Outfall
mgd
34.7
32.9
Sufficient capacity for
current and year 2024 peak
flow
DAF Thickener
lb
TSS/d/sf
-
> 22.66
-
-
22.6
-
Sufficient capacityto serve
to year 2024 conditions:
however, system has no
redundancy provided
City kima Wastewater Facility Plan — DRAFT 8/12/05
48
Table 5-12
Summary of Unit Process Capacity
Firm Capacity
Year 2024 Flow/Load
Unit Process
Units
Average'
Maximum`
Month
Peak3
Hour
Average
Maximum
Month
Peak
Hour
Comment
Primary Digesters
HRT (d)
19
13
-
(7)
(7)
-
Needs new digester to meet
additional capacity
requirement for 2024 and to
ensure Class B detention
requirements if existing 70
ft diameter digester goes
out of service at current
conditions.
Secondary Digesters
HRT (d)
7
5
-
(7)
(7)
-
Centrifuge
gpm
-
240
-
-
-
-
Sufficient capacity to meet
year 2024 maximum month
conditions; however,
centrifuge is near end of its
life and no redundancy is
provided
1 Current Average, 11.3 mgd
2 Current Maximum Month, 16.8 mgd
3 Current Peak Hour, 24 mgd
Under Del Monte discharge loading conditions
' Reliability Class 1I standards allow secondary clarifier
capacity to be 50 percent of design flow.
6 With polymer addition
7 Refer to Section 5.4.8 for discussion on digester capacity
analysis
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05
Page 5-49
SECTION 6
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT
STRATEGIES
6.1 Introduction
This Section provides recommendations for future wastewater treatment modifications
and expansions to meet the Yakima Regional WWTP's projected future capacity and
regulatory effluent quality requirements. In addition, discussions on air emission
treatment for the facility and treatment plant resource requirements are presented.
6.2 Existing Facilities Needs and Improvements
Section 5 identified processes that are necessary to meet future plant capacity
requirements. The following section presents these processes, as well as those that merit
an in-depth analysis for future plant upgrade improvements. In some instances, multiple
alternatives were offered and evaluated. Evaluation of the biosolids treatment processes
and management are discussed in Section 9.
6.2.1 Headworks/Preliminary Treatment
The grit storage hopper in the influent building is used to store grit that is discharged
from the grit removal process. The existing grit storage hopper experiences bridging of
grit at the discharge and is deteriorating due to problems with the vibratory process that is
leading to cracks and seepage.
It is recommended that upgrades/improvements be provided to the existing grit storage
hopper to reduce material bridging and extend the functional life of the equipment to
beyond the planning period. Needed improvements may include correction of the
vibratory unit operation, enhancement of air quality collection, and installation of controls
for seepage from the hopper. A new coating system or the installation of a Teflon -like
lining will also be investigated for the interior of the grit storage hopper.
The existing storage hopper would be removed from service while valves, gates and
vibratory equipment, if required, are being repaired. Structural members would be added
to the hopper in locations where cracking and weld failure is occurring. Following repair
of the hopper steel structure, the entire structure would be blasted and painted.
The opinion of probable costs of the recommended upgrades/improvements to the grit
storage hopper is presented in Table 6-1.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-1
Table 6-1
Opinion of Probable Cost for the Grit Storage Hopper Upgrades/Improvements
Unit
Opinion of Probable Cost
Repair Existing Hopper
Facility Retrofits
$50,000
Electrical and Instrumentation
$12,000
Site Work and Yard Piping
$10,000
Subtotal
$72,000
Contingency (30%)
$22,000
Subtotal Costs
$94,000
Engineering, legal and fiscal (25%)
$24,000
Total Opinion of Probable Cost
$118,000
6.2.2 Primary Treatment
Wastewater flows from the Parshall flumes through uncovered channels and into one of
the two primary clarifier influent split box chambers. Flow exits the flow split box
through four 30 -inch Primary Clarifier influent pipes controlled with sluice gates. The
ten -inch telescoping valves located in each chamber for scum removal have not done an
adequate job of removing the scum, and leakage through the sluice gates makes isolation
of the primary clarifiers difficult. Also, influent solids tend to be directed straight ahead,
creating a poor solids flow split that directs more solids to Primacy Clarifiers Nos. 2 & 3.
To alleviate these problems, a retrofit of the split box structure is recommended.
Retrofits to the flow split box will include installation of scum removal troughs. An
automated scum removal unit will be installed in each of the primary influent flow split
channels. Each of these troughs will include a 30 -inch wide automated weir gate and
• scum trough. They will collect scum from the water surface of the flow split box when
needed or on a time cycle basis. The 30 -inch wide automated weir gate will have a
vertical range of three feet.
The existing primary influent sluice gates are used for control of flow to each of the
primary clarifiers. Although the flow split arrangement is not ideal, plant staff has
indicated the submerged gates do an acceptable job at controlling the flow split to the
clarifiers. Currently, the existing flow split directs more solids to Primary Clarifiers No.
2 and No. 3. The existing gates do leak, thus preventing operations staff from isolating
the basins completely. Replacement of the sluice gates in the existing split box is
recommended. -
The opinion of probable costs for retrofit of the primary treatment split box is presented
in Table 6-2.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-2
Table 6-2
Opinion of Probable Cost for Retrofitting the Primary Treatment Split Box
Unit
Opinion of Probable Cost
(to Build -out)
Retain Existing Box
Facility Retrofits
$185,000
Electrical (15%)
$28,000
UC (7 %)
$13,000
Site Work and Yard Piping (20%)
$37,000
Subtotal Costs
$263,000
Contingency (30%)
$79,000
Subtotal
$342,000
Engineering, legal and fiscal (25%)
$86,000
Total Opinion of Probable Cost
$428,000
6.2.3 Trickling Filter System
Two 170 -foot diameter rock media trickling filters are in use at the Yakima Regional
WWTP. Wastewater fromthe primacy clarifiers enters the trickling filter pumping station
where it is mixed with trickling filter re -circulation flow before being pumped to the
trickling filters. A trickling filter clarifier was recently returned to operation for settling
trickling filter solids to reduce the load to the aeration basins. Two alternatives were
considered for future trickling filter operations.
6.2.3.1 Alternatives Considered
In previous improvements to the trickling filters, motor drives were installed to enable
slowing the rotational speed of the distribution arms to allow media flushing. Ventilation
was also added with treatment of the exhaust for odor control. The trickling filter
clarifier was returned to operation with dewatering capability in 2002.
Providing additional ventilation and air is not expected to increase trickling filter
capacity, as oxygen transfer to the liquid is already considered to be maximized. The two
options considered for future trickling filter operation improvements were as follows:
• Retrofit plastic media
• Add new trickling filter clarifier
Retrofit Plastic Media
Plastic trickling filter media provides a lightweight alternative to conventional rock. This
allows plastic media filters to be constructed to depths of 20 feet or more in some cases.
As a retrofit option, the existing rock media would be replaced with plastic media to the
existing depth of 8 feet. When compared with the actual performance of the existing rock
media, it is not projected that the plastic media would significantly improve performance.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-3
Currently, the existing rock media is rated for a maximum month organic load of
90 lb/kcf/d and it is not expected that the organic load limit would be increased with
plastic media.
The opinion of probable cost for plastic media is presented in Table 6-3.
Table 6-3
Opinion of Probable Cost for Plastic Media
Item Description
Opinion of Probable Cost
Plastic Media Addition
Facility Construction and Retrofits
$760,000
Site Work and Yard Piping (20%)
$152,000
Subtotal Costs
$912,000
Contingency (30%)
$209,800
Subtotal
$1,258,600
Engineering, legal and administration (25%)
$340,700
Total Opinion of Probable Cost
$1,700,000
Add New Trickling Filter Clarifier
The existing trickling filter clarifier is a single 170 -foot -diameter unit with a relatively
shallow sidewater depth of only 8 feet. To provide redundancy and allow for better
maintenance, a new unit could be added. It was assumed that the new unit would be 140
foot diameter with a sidewater depth of 15 feet similar to the existing secondary clarifiers.
The new unit would have full dewatering capabilities.
The opinion of probably cost for the trickling filter clarifier is presented in Table 6-4.
Table 6-4
Opinion of Probable Cost for Trickling
Filter Clarifier
Item Description
Opinion of Probable Cost
New TF Clarifier
Facility Construction and Retrofits
$1,250,000
Electrical
$186,000
I/C (7 %)
$88,000
Site Work and Yard Piping
$250,000
Subtotal Costs
$1,774,000
Contingency (30%)
$532,000
Subtotal
$2,306,000\
Engineering, legal and administration (25%)
/ $577,000
Total Opinion of Probable Cost
1 $2,883,000
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 6-4
6.2.3.2 Recommendations
The plastic trickling filter media is expensive and is not projected to result in a significant
improvement in treatment at the shallow depth of 8 feet. Therefore, it is recommended
that the existing media not be replaced and current trickling filter operations continue into
the future. When additional capacity is needed, it will be obtained by expanding the
activated sludge process.
The existing trickling filter clarifier is a critical component to the overall treatment
process during the three-month period of Del Monte loads, but as discussed in Section 5,
is not a critical component during other seasons (until year 2014 — when it is critical for
maximum month domestic loading conditions year-round). Therefore, it is possible to
take the existing unit out of service during the remaining nine months for essential
maintenance. Given these conditions of operation, a second clarifier dedicated only to
trickling ,filter effluent is not deemed necessary, as the activated sludge process has
adequate capacity for treatment during most of the year without the trickling filters.
6.2.4 Activated Sludge System
The activated sludge system at the Yakima Regional WWTP is a biological process that
accomplishes carbonaceous BOD and ammonia removal. Although not optimized for it,
the existing process does provide some removal of nitrate and phosphorus. In developing
alternatives for the activated sludge system, the trickling filters were assumed to continue
in the current mode of operation with a maximum month organic load limit of
approximately 90 lb/kcf/d. This limits the trickling filter hydraulic loading to about 11.8
mgd, with excess flow bypassed directly to the aeration basins. Under those operating
conditions, the existing aeration basins have adequate capacity to treat flows expected
through about 2018. Several alternatives were examined for improving activated sludge
operations and increasing capacity in the future. The alternatives considered can all be
altered to incorporate anaerobic zones (and/or chemical addition) for phosphorous
removal if needed for future effluent limits.
6.2.4.1 Alternatives Considered
Alternative 1: Upgrade Existing Aeration Basins, Build Internal Anoxic Zone
Under this alternative, the existing aeration basin complex would be improved by
providing an internal anoxic selector zone to provide denitrification treatment facilities,
as illustrated in Figure 6-1. A design summary of Alternative 1 is presented in Table 6-5.
The new anoxic selector zone volume is approximately 525,000 gallons (70,000 cubic
feet), and will provide a MLSS recycle rate of twice the average influent flow. This
anoxic zone will result in effluent nitrate levels below 5.0 mg/L. The anoxic selector
basin and activated sludge treatment system will provide sufficient capacity until the year
2018.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 6-5
Alternative 2: Build New Aeration Basin, Build Internal Anoxic Zone
Under this alternative, the existing aeration basin complex would be improved by
providing additional aeration basin capacity to meet maximum month loading conditions
for 2024 conditions. (See Figure 6-2.) The selector basin is sized to meet build out
conditions and provide adequate denitrification through the planning period. A design
summary of Alternative 2 is presented in Table 6-6.
The new anoxic selector zone volume is approximately 524,000 gallons (70,000 cubic
feet), and will provide a MLSS recycle rate of twice the influent flow. This anoxic zone
will result in effluent nitrate levels below 5.0 mg/L. The existing aeration basin volume
is approximately 4.2 million gallons (561,600 cubic feet). To provide expansion of the
aeration basin system in a logical increment, this alternative utilizes an additional aeration
basin sized at 1.05 million gallons (140,400 cubic feet). The additional aeration basin
will provide adequate capacity through the year 2024. The new basin would be
constructed south of the existing Aeration Basin No. 4. The existing metal storage
building in the vicinity of the future construction site would be relocated.
Table 6-6
Alternative 2 Facility Summary
New Aeration Basin, Internal Anoxic Zone - Sufficient Capacity through 2024
Total Plant Capacity
16.3 mgd
Anoxic Basin
Volume
MLSS recycle rate
524,000 gal
(1-4)*Q (annual average flow)
Aeration Basin (existing)
Number
Volume, each
Volume, total
4
140,400 cf (1.05 mgal)
561,600 cf (4.2 mgal)
Aeration Basin (new)
Number
Volume, each
Volume, total
1
140,400 cf (1.05 mgal)
140,400 cf (1.05 mgal)
Secondary Clarifiers (existing)
Number
Dimensions
SWD
Surface Area
2
140' Dia.
15ft
15,400 sf each / 30,800 sf total
Secondary Clarifier (new)
Number
Dimensions
SWD
Surface Area
1
140' Dia.
15ft
15,400 sf each / 30,800 sf total
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 6-7
Figure 6-2. Construct New 1.05 MG Aeration Basin and Internal Anoxic Zone
INFLUENT FLOW
SPL T BOX
MLSS RECYCLE
MLSS RECYCLE
1
nauent from anodc zone
NEW
AERATION
BASIN
r
NEW
SC
Alternative 3: Upgrade Existing Aeration Basins, Build Two New Aeration Basins
and Internal Anoxic Zone to Provide Sufficient Capacity to Build Out Conditions
This alternative is similar to the previous alternative, except additional aeration basin
capacity would be added to provide sufficient treatment for build out conditions. (See
Figure 6-3.) Design summary of Alternative 3 is presented in Table 6-7.
The new anoxic selector zone volume is approximately 524,000 gallons (70,000 cubic
feet), and will provide a MLSS recycle rate of twice the influent flow. This anoxic zone
will result in effluent nitrate levels below 5.0 mg/L. The existing aeration basin volume
is approximately 4.2 million gallons (561,600 cubic feet). To provide expansion of the
aeration basin system in a logical increment, this alternative utilizes two additional
aeration basin sized at 1.05 million gallons (140,400 cubic feet) each, for a total volume
of 2.1 million gallons. The additional aeration basin will provide adequate capacity
through buildout conditions.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-8
AERATION
BASIN 2
R 2 !AERATION
0 N I BASIN t
AERATION
__I
AERATION
BASIN 3
BASIN 4
1
nauent from anodc zone
NEW
AERATION
BASIN
r
NEW
SC
Alternative 3: Upgrade Existing Aeration Basins, Build Two New Aeration Basins
and Internal Anoxic Zone to Provide Sufficient Capacity to Build Out Conditions
This alternative is similar to the previous alternative, except additional aeration basin
capacity would be added to provide sufficient treatment for build out conditions. (See
Figure 6-3.) Design summary of Alternative 3 is presented in Table 6-7.
The new anoxic selector zone volume is approximately 524,000 gallons (70,000 cubic
feet), and will provide a MLSS recycle rate of twice the influent flow. This anoxic zone
will result in effluent nitrate levels below 5.0 mg/L. The existing aeration basin volume
is approximately 4.2 million gallons (561,600 cubic feet). To provide expansion of the
aeration basin system in a logical increment, this alternative utilizes two additional
aeration basin sized at 1.05 million gallons (140,400 cubic feet) each, for a total volume
of 2.1 million gallons. The additional aeration basin will provide adequate capacity
through buildout conditions.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-8
Table 6-7
Alternative 3 Facility Summary
New Aeration Basins, Internal Anoxic Zone - Sufficient Capacity through Buildout Conditions
Total Plant Capacity
17.0 mgd
Anoxic Basin
Volume
MLSS recycle rate
500,000 gal
(1-4)*Q (annual average flow)
Aeration Basin (existing)
Number
Volume, each
Volume, total
4
140,400 cf (1.05 mgal)
561,600 cf (4.2 mgal)
Aeration Basin (new)
Number
Volume, each
Volume, total
2
140,400 cf (1.05 mgal)
280,800 cf (2.1 mgal)
Secondary Clarifiers (existing)
Number
Dimensions
SWD
Surface Area
2
140' Dia.
15 ft
15,400 sf each / 30,800 sf total
Secondary Clarifier (new)
Number
Dimensions
SWD
Surface Area
1
140' Dia.
15 ft
15,400 sf each / 30,800 sf total
Figure 6-3. Construct Two New 1.05 MG Aeration Basin and External Anoxic Zone
RAS
INFLUENT FLOW
SPLIT BOX
MLSS RECYCLE
l
nfluen1 from anoxic zone
I
MISS RECYCLE .- — — —
NEW
AERATION
BASIN
NEW
AERATION
BASIN
1.4.1
SC
7
NEW
SC
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-9
AERATION
BASIN 2
� X Z (AERATION
1 z N I BASIN 1
I.a I
_
AERATION
AERATION
BASIN 3
BASIN 4
l
nfluen1 from anoxic zone
I
MISS RECYCLE .- — — —
NEW
AERATION
BASIN
NEW
AERATION
BASIN
1.4.1
SC
7
NEW
SC
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-9
6.2.4.3 Alternatives Evaluation
The opinion of probable costs of the aeration basin system alternatives are presented in
Table 6-8.
Table 6-8
Opinion of Probable Cost for Aeratior(Basin System Alternatives
Unit
Opinion
of Probable Cost
New
Internal
Anoxic Zone
New Aeration
Basin, Internal
Anoxic Zone
New Aeration
Basins (2),
Internal Anoxic
Zone
Aeration Basin Construction and
Retrofits
$200,000
$835,000
$1,470,000
Electrical & Instrumentation
$60,000
$251,000
$441,000
Site Work and Yard Piping
$251,000
$441,000
Subtotal Costs
$260,000
$1,337,000
$2,352,000
Contingency (30%)
$78,000
$401,000
$706,000
Subtotal
$338,000
($1,738,000
$3,058,000
Engineering, legal and fiscal (25%)
, $85,000
$435,000
$76,5,Q00
Total Opinion of Probable Cost
r' $423,000 "
, C$2,173,000 ';
$3;823,000\
Alternative 1, which offers no increase in aeration basin capacity, is a feasible option
should regulatory requirements call for nitrification and denitrification in the future:
Alternative 2 provides aeration basin capacity needed after 2018. By constructing two
new basins at the same time, Alternative 3 provides uniform redundancy and simpler
construction sequences than Alternative 2. However, the second aeration basin will not
be needed until after 2024.
6.2.4.4 Recommendation
Construction of a new aeration basin and an internal anoxic zone to meet capacity
requirements prior to 2018 is recommended. Figure 6-4 shows the proposed site layout of
the new aeration basin and other recommended facilities.
6.2.5 Secondary Clarifiers
Section 5 identifies the need for an additional secondary clarifier to meet solids loading
redundancy needs at peak loading conditions. .ln .addition; to-xxte_ et the WDOE Class_.I-..
reliability criteria, a new 140 -foot diameter secondary clarifier is required iniriiediately.
To meet Class II reliability criteria, which is the current plant classification, the new
clarifier will not be required until after 2024 from a hydraulic loading standpoint. The
new clarifier will be constructed similar to the two existing units. The proposed location
for the new Secondary Clarifier is south of existing Secondary Clarifier No. 2, located on
a portion of the decommissioned north Lagoon (Figure 6-4).
The opinion of probable cost for the new secondary clarifier is presented in Table 6-9.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-10
6.2.4.3 Alternatives Evaluation
The opinion of probable costs of the aeration basin system alternatives are presented in
Table 6-8.
Table 6-8
Opinion of Probable Cost for Aeration Basin System Alternatives
Unit
Opinion
of Probable Cost
New
Internal
Anoxic Zone
New Aeration
Basin, Internal
Anoxic Zone
New Aeration
Basins (2),
Internal Anoxic
Zone
Aeration Basin Construction and
Retrofits
$200,000
$835,000
$1,470,000
Electrical & Instrumentation
$60,000
$251,000
$441,000
Site Work and Yard Piping
$251,000
$441,000
Subtotal Costs
$260,000
$1,337,000
$2,352,000
Contingency (30%)
$78,000
$401,000
$706,000
Subtotal
$33 8,000
$1,738,000
$3,058,000
Engineering, legal and fiscal (25%)
$85,000
$435,000
$765,000
Total Opinion of Probable Cost
$423,000
$2,173,000
$3,823,000
Alternative 1, which offers no increase in aeration basin capacity, is a feasible option
should regulatory requirements call for nitrification and denitrification in the future.
Alternative 2 provides aeration basin capacity needed after 2018. By constructing two
new basins at the same time, Alternative 3 provides uniform redundancy and simpler
construction sequences than Alternative 2. However, the second aeration basin will not
be needed until after 2024.
6.2.4.4 Recommendation
Construction of a new aeration basin and an internal anoxic zone to meet capacity
requirements prior to 2018 is recommended. If effluent phosphorous limits are added, the
basin configuration will have to be altered to incorporate anaerobic zones and/or chemical
addition to the secondary clarifiers considered. Figure 6-4 shows the proposed site layout
of the new aeration basin and other recommended facilities.
6.2.5 Secondary Clarifiers
Section 5 identifies the need for an additional secondary clarifier to meet solids loading
redundancy needs at peak loading conditions. In addition, to meet the WDOE Class I
reliability criteria, a new 140 -foot diameter secondary clarifier is required immediately.
To meet Class II reliability criteria, which is the current plant classification, the new
clarifier will not be required until after 2024 from a hydraulic loading standpoint. The
new clarifier will be constructed similar to the two existing units. The proposed location
for the new Secondary Clarifier is south of existing Secondary Clarifier No. 2, located on
a portion of the decommissioned north Lagoon (Figure 6-4).
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 6-10
The opinion of probable cost for the new secondary clarifier is presented in Table 6-9.
Table 6-9
Opinion of Probable Cost for New Secondary Clarifier
Item Description
Opinion of Probable Cost
New Secondary Clarifier
Facility Construction
$1,461,000
Electrical (15%)
$219,000
UC (7 %)
$102,000
Site Work and Yard Piping
$292,000
Subtotal Costs
$2,074,000
Contingency (30%)
$622,000
Subtotal
$2,696,000
Engineering, legal and administration (25%)
$674,000
Total Opinion of Probable Cost
$3,370,000
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 6-11
SCALE: P=100'
StORACE
r et 06
ti
SOUTH LAGOON
11/
BLACK & VEATCH
Block & Veatch Corporotion
Seattle, Woshington
CEN TRATE_/1
STORAGE
NCRTH LAGOON
(OISCONTM, 0)
RAS/WAS
PUMP STATION
(NEW)��
%C0N0ARY
CLAW/ER 3
NEW)
OAF
THICKENER
(NEW)
YARO
Pt/
A1C$
YARD
PtATRINO
VATK
4E1ER
HA
I. . 4
TR OMAR
STANDBY
POWER
°LOG
(NEW)
°LOYIER
BLDG
(NEw)—
AE ATICN
0 SIN 6
(AF :R 2024)
AERATI
BASH
(BY 201
SA/6S1A CON
NO. S —
SHOP
GARAGED
t7FFiOE
BALER
BL DC
-OlPIA TER
SEPARATc
PRIUARY
DIGESTER
(NEW)
PRTMARY
CLAPPER 2
PRTMARY
DIGESTERS
DIGESTER
BLOC
PRIMARY
WASTERS
PRIMARY
DIGESTERS
SI.'BSTA TIC$
NO, 2
HANN.NG
BL0G
SOWS
sEoccioARY
O4CESTESTEIRS
BLOWER
[ FUER
DAF
RIOG
.CERA nON
RASA S
AVM PON
RASIN 4
SfCC$OARY
CLIPPER 2
OAF
THICKENER
AERADON
BASIN 2
AERA ITCH
BASIN 1
SLUDGE TRANSFER
PtA4RNG STANCH
1%OOIFIC TicNs
POLYMER
SYSTEM
(NEW)
SECONDARY
CtARWCR 1
G`ILCRNE
UT%NG
rHAI,fOE
a
AOWN MO01
ABORATOR
StUOCE
TRANS,
BLDG
PFRUARY
CLARIFIER 1
PRIMARY
Ct. ART, ER 4
SOVTH
I RK?NL NYC
Ft TER
NDt1SIRlAl '.4ASTE U
PI.iNPINNC STA TK*1
TTCKIUNG Flt, TER
PUMPING STATIC$
NORTH
IRK?TLNG
Ft TER
TERMEC4A 1F
DECRITIER
MGM! TER
YANG SIADEAR
ODOR CON MO.
SCRUBBER
(IYPL—
TRICKLING FUER
CLARW ER Poo, SIA rGN
OECHLERA TTON
SLOG
TmcXtaNG
FLIER
Q.mar'ER
(3itCPNE C(NTLCI CI.4CYaHAI10$
TANK STDG
!LAI'STA n
N0.4
FIGURE 6-4
CITY OF YAKIMA
YAKIMA REGIONAL WASTEWATER TREATMENT PLANT
PROPOSED SITE PLAN
n
FSO
URE
ERA.
TRAILER
STORAGEUPS
OS
I
NCCAN
D
OAF
BLDG
HEW)
/
(NEW)
SLUDGE
DRYING
# DS
HANQU
BUILDING
-____A
4G
--
SOUTH LAGOON
11/
BLACK & VEATCH
Block & Veatch Corporotion
Seattle, Woshington
CEN TRATE_/1
STORAGE
NCRTH LAGOON
(OISCONTM, 0)
RAS/WAS
PUMP STATION
(NEW)��
%C0N0ARY
CLAW/ER 3
NEW)
OAF
THICKENER
(NEW)
YARO
Pt/
A1C$
YARD
PtATRINO
VATK
4E1ER
HA
I. . 4
TR OMAR
STANDBY
POWER
°LOG
(NEW)
°LOYIER
BLDG
(NEw)—
AE ATICN
0 SIN 6
(AF :R 2024)
AERATI
BASH
(BY 201
SA/6S1A CON
NO. S —
SHOP
GARAGED
t7FFiOE
BALER
BL DC
-OlPIA TER
SEPARATc
PRIUARY
DIGESTER
(NEW)
PRTMARY
CLAPPER 2
PRTMARY
DIGESTERS
DIGESTER
BLOC
PRIMARY
WASTERS
PRIMARY
DIGESTERS
SI.'BSTA TIC$
NO, 2
HANN.NG
BL0G
SOWS
sEoccioARY
O4CESTESTEIRS
BLOWER
[ FUER
DAF
RIOG
.CERA nON
RASA S
AVM PON
RASIN 4
SfCC$OARY
CLIPPER 2
OAF
THICKENER
AERADON
BASIN 2
AERA ITCH
BASIN 1
SLUDGE TRANSFER
PtA4RNG STANCH
1%OOIFIC TicNs
POLYMER
SYSTEM
(NEW)
SECONDARY
CtARWCR 1
G`ILCRNE
UT%NG
rHAI,fOE
a
AOWN MO01
ABORATOR
StUOCE
TRANS,
BLDG
PFRUARY
CLARIFIER 1
PRIMARY
Ct. ART, ER 4
SOVTH
I RK?NL NYC
Ft TER
NDt1SIRlAl '.4ASTE U
PI.iNPINNC STA TK*1
TTCKIUNG Flt, TER
PUMPING STATIC$
NORTH
IRK?TLNG
Ft TER
TERMEC4A 1F
DECRITIER
MGM! TER
YANG SIADEAR
ODOR CON MO.
SCRUBBER
(IYPL—
TRICKLING FUER
CLARW ER Poo, SIA rGN
OECHLERA TTON
SLOG
TmcXtaNG
FLIER
Q.mar'ER
(3itCPNE C(NTLCI CI.4CYaHAI10$
TANK STDG
!LAI'STA n
N0.4
FIGURE 6-4
CITY OF YAKIMA
YAKIMA REGIONAL WASTEWATER TREATMENT PLANT
PROPOSED SITE PLAN
6.2.6 RAS/WAS Pumping
Return activated sludge is currently transported from the secondary clarifiers back to the
aeration basin flow control structure through two constant speed open screw pumps.
Each of these RAS pumps has a capacity of 13,500 gpm and, based upon a return rate of
60 percent of the influent flow, each of the RAS pumps can maintain sufficient return
flows to serve 2024 annual average and peak hour conditions. The pumping facilities do
not have sufficient capacity to handle the build -out peak hour flow conditions unless
adjustment is made to the minimum return rates. Waste activated sludge and secondary
scum are pumped from the two existing secondary clarifiers through two separate
pumping systems that have sufficient capacity to serve the existing basins.
Providing additional secondary clarifier and aeration basin capacities will require
connection of these new facilities into the existing pumping stations. However, site
piping and electrical utility congestion in the vicinity of the existing RAS Pumping
Station prohibit such connections.
There are two remaining options: 1) install a new RAS/WAS pump station to support
both existing and new aeration basins and secondary clarifiers; 2) installation of a new
RAS/WAS pump station to support only the new secondary clarifier as well as future
aeration basins.
While the first option to support all secondary treatment process units has the benefit of
enabling better system redundancy and reliability, as well as potentially offering less
intensive operations and maintenance, it presents numerous challenges for tying new
RAS/WAS piping into both the existing and new secondary clarifiers and aeration basins
in an area that is already congested. Therefore, this option was not evaluated any further.
Although similar challenges remain present, installation of a new RAS/WAS pump
station to support only the new secondary clarifier and future aeration basin is deemed
more feasible. The existing RAS/WAS pumping units would remain in service to support
the existing aeration basins and secondary clarifiers. Upon installation of a third
secondary clarifier, a new pumping station would be constructed to accommodate the new
process unit. The new RAS/WAS pump station would be constructed adjacent to the new
secondary clarifier (Figure 6-4). The RAS pumps and the WAS pumps would be sized to
meet a 100 percent RAS return rate condition.
The opinion of probable costs of the RAS/WAS pump station are presented in Table 6-
10. This opinion of probable cost is based on providing the capacity for year 2024
conditions with the ability to easily expand to ultimate build -out. The opinion of costs
also includes electrical additions required for the existing and new RAS/WAS pump
stations.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-13
Table 6-10
Opinion of Probable Cost for New RAS/WAS Pump Station
Item Description
Opinion of Probable Cost
Facility Construction
$350,000
Electrical & Instrumentation
$90,000
Site Work and Yard Piping
$125,000
Subtotal Costs
$565,000
Contingency (30%)
$170,000
Subtotal
$735,000
Engineering, legal and fiscal (25%)
$184,000
Opinion of Probable Cost
$919,000
Electrical Additions to Existing and New RAS/WAS
Pump Stations
$62,000
Contingency (30%)
$19,000
Subtotal
$81,000
Engineering, legal and fiscal (25%)
$20,000
Opinion of Probable Cost
$101,000
Total Opinion of Probable Cost
$1,020,000
6.2.7 Aeration Blowers
The existing aeration blower system installed at the Yakima WWTP is nearing the end of
its service life and needs to be rehabilitated or replaced. The purpose of this evaluation is
to determine whether to rehabilitate components of the existing blower system or to
replace the existing blowers with new units. Aside from rehabilitation options, the
evaluation will consider use of single stage centrifugal blowers, multi -stage centrifugal
blowers, new positive displacement blowers, and possibly construction of a new blower
building.
6.2.7.1 Analysis of Existing System
The existing blower system has a number of issues that need to be addressed. The
following are the known issues:
• The existing blowers need to be serviced frequently. Operators report that at least
one unit is always out of service. The existing variable frequency drives (VFDs)
appear to be the cause of most problems. The existing Siemens VFDs are older
technology units that require added maintenance. Control cards require frequent
replacement.
• When operating at their rated capacity of 5500 icfm, the existing blowers appear
to require a speed of about 1925 rpm. This is approximately 7% over the rated
motor speed of 1800 rpm. This "overspeed" operation is not recommended by
motor manufacturers for direct drive units, such as the existing Yakima blowers.
Overspeeding the motors reduces torque output of the motor and increases motor
temperature. Both of these conditions are harmful to the motor and reduce service
life.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-14
• The existing blowers are very loud. This is possibly due to a resonance condition
that may be occurring in the piping. Resonance can occur when silencers are not
located within approximately 2 feet of the blower. The inlet and discharge
silencers do not appear to be located close enough to the blower. If resonance is
occurring, this would be a source of increased noise and vibration that would
potentially shorten the life of the blower bearings.
• The total firm capacity of the existing blowers is 14,250 scfm. The required firm
capacity is 10,530 scfm. Therefore, any new blower system being considered will
actually be downsized compared to the existing blower system.
6.2.7.2 Alternatives Considered
This blower evaluation will consider five options for blower system improvements. The
five options are listed below:
Option 1: Replace the four existing motors and four existing VFDs. Install VFDs in
a new enclosure.
Option 2: Replace the four existing motors and four existing VFDs. Install VFDs in
a new enclosure. Send blower back to the manufacturer for rebuilding to
obtain a new 90 day warranty.
• It is recommended that blowers should be operated at not more
than a maximum speed of 1800 rpm.
Option 3: Install four new positive displacement blowers with VFDs in a new
blower building.
• 4 blowers (3 duty, 1 standby) rated for 3,510 scfm @ 12.3 psig
Option 4: Install three new single stage centrifugal blowers in a new blower
building.
• 3 blowers (2 duty, 1 standby) rated for 5,265 scfm @ 12.3 psig
Option 5: Install three new multistage centrifugal blowers in a new blower building.
• 3 blowers (2 duty, 1 standby) rated for 5,265 scfm @ 12.3 psig
The total firm capacity required for any new blower system is 10,530 scfm. Option 3
requires use of 3 duty belt driven blowers (instead of 2 duty blowers) so that the motor
"overspeeding" issue can be avoided. A 2 duty PD blower arrangement would require the
blower to operate at speeds in excess of 1800 rpm in order to produce the required flow.
Installing 3 smaller duty PD blowers avoids this problem.
Options 3, 4 and 5 require consideration of a new blower building because it would be
difficult to fit these large units inside the existing blower room. If the existing building
is reused, additional costs may be incurred as the contractor would have to provide
temporary air to the aeration basins between the time when the existing blowers are
removed and the new blowers are installed.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-15
6.2.7.3 Blower Types
Three different types of blowers were considered in this evaluation: Rotary lobe positive
displacement, single stage centrifugal and multi -stage centrifugal. Table 6-11 points out
the key advantages and disadvantages of each type of machine.
Table 6-11
Discussion of Blower Types
Type
Advantages
Disadvantages
Rotary Lobe Positive
Displacement
• Will operate over a wide
range of discharge pressures
and provide a relatively
constant air flow at constant
speed regardless of pressure
required.
• Off-the-shelf item. Although
packaging is custom for each
project, blower is not, so
delivery lead times may be
shortened.
• Capital costs are low for the
bare blower, and comparable
with multistage centrifugal
after accessories are added.
• Best suited for low flow,
higher pressure applications,
or applications where
pressure requirement varies
significantly.
• Space requirements are
significant when silencers are
added.
• Low frequency noise is
significant and hard to
attenuate with silencers.
Therefore, silencers are large.
Noisiest of the 3 types.
• Lowest efficiency.
• Higher maintenance than
multistage due to metal to
metal contact of the timing
gears.
• High vibration and pulsations
produced.
• Speed must be varied to vary
flow. Addition of VFDs adds
significant cost.
• Relief valve required.
Single Stage Centrifugal
• Very efficient operation
minimizes power costs.
• Better turndown capability
than a multistage. (Multistage
machines can be turned down
to about 60% of capacity
versus 45% for single stage.)
• Precision machinery with
close tolerances. More
precise manufacturing
methods are required due to
the higher operating speeds.
• High capital costs.
• Complicated design with
more moving parts. Although
maintenance costs are
difficult to quantify, this
would seem to indicate higher
maintenance costs.
• (A gear box, pressurized oil
system, and forced cooling
system are required).
• Some maintenance tasks will
require a factory service
technician, such as cleaning
of the linkage mechanism
which moves the inlet guide
vanes and variable diffuser
vanes,
• Very high operating speeds
(nonnally at Ieast10,000 rpm,
and may be as high as 20,000
rpm).
• Significant high frequency
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 6-16
Table 6-11
Discussion of Blower Types
Type
Advantages
Disadvantages
noise resulting in the need for
inline silencers on both the
inlet and discharge side, or a
sound enclosure in some
cases.
Multi -stage Centrifugal
• Reasonable capital costs.
• Simplicity of design including
fewer moving parts than single
stage blowers, and no metal-
to -metal contact except
bearings. Although
maintenance costs are difficult
to quantify, this would seem to
indicate lower maintenance.
• Routine maintenance can be
handled by plant personnel.
• The operating speed is 3600
rpm.
• Noise level usually limited to
90 dBA at 3 feet with only a
combination filter silencer
required.
• Less efficient than single stage
machines.
• Less turndown capability than
single stage. (Multistage
machines can be turned down
to about 60% of capacity
versus 45% for single stage.)
• Tolerances greater than with a
single stage machine, and
manufacturing methods are
less precise.
• There are few installations of
multistage machines with
adjustable frequency drives. If
adjustable speed drives are to
be used, the blower must be
carefully selected with variable
speed operation in mind.
6.2.7.4 Evaluation
The evaluation was based on a 20 year present worth analysis. The present worth analysis
accounts for initial capital costs as well as power costs incurred over a 20 year period.
Some blower options may have high initial capital costs and lower energy consumption;
other options may have low initial capital costs and higher energy usage. To account for
these differences, the present worth analysis essentially determines how much money the
owner would need today in order to purchase, install, and operate the equipment for 20
years.
In order to perform this evaluation, blower manufacturers were solicited for blower
selection information including budgetary pricing, typical scope of supply, dimensional
data, and energy consumption data. The evaluation was based primarily on their
responses.
The evaluation considered the following key criteria:
• Initial capital costs
• Energy costs
• O&M costs
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-17
• Provisions for temporary air (if necessary) when transitioning to a new blower
system
The following assumptions were made for this evaluation:
• Interest rate of 5 %.
• Construction of a blower building in Yakima, WA, is $144/sf (based on B&V
historical data).
• Power consumption figures are based on "annual average" conditions. For this
evaluation annual average conditions used were an ambient temperature of 60 F
and a relative humidity of 35%. These assumptions primarily affect the power
consumption data.
• Initial power cost of $0.037/kW-hr.
While the initial power costs are known, it is difficult to know how inflation will affect
the future cost of electricity. The assumption made for the future cost of electricity is a
critical component in the evaluation. Since predicting this cost is virtually impossible to
do, a range of present worth values are presented as a sensitivity analysis.
In general, there is not much variance in the total present worth costs for the different
options. The total present worth cost is calculated using the following equation:
Total Present Worth Cost = Initial Capital Cost + Present Worth Energy Costs
The initial capital costs do not change based on different assumptions for inflation.
Present worth energy costs are the energy costs incurred by the owner over a 20 year
period. The present worth energy costs are greatly affected by the assumed cost of
electricity inflation rate.
Several factors were considered in evaluating the blower options as follows:
• Initial Capital Cost
• Total Present Worth Cost
• Advantages / Disadvantages specific to each option
6.2.7.4.1 Initial Capital Cost
Initial capital costs are the sum of costs for new or rehabilitated equipment, installation of
equipment, a new building (if applicable), and other miscellaneous piping modifications.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-18
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
0
w
0
o
o
Assumed Cost of Electricity
Annual Inflation Rate
Table 6-13
Present Worth Energy Costs (in millions of dollars)
o
�,
ch
u,
4"
Option 1: Replace the four existing
motors and four existing VFDs.
N
o
`
O1
1.78
Option 2: Replace the four existing
motors and four existing VFDs.
Send blower back to the
manufacturer for rebuild.
A
2.57
:—
N
Option 3: Install three new positive
displacement blowers with VFDs in
a new blower building.
"
N
o
Option 4: Install two new single
stage centrifugal blowers in a new
blower building.
N
N
-4
Option 5: Install two new
multistage centrifugal blowers in a
new blower building.
o< N
•CD •
CI' N
(15- cr
o
o
(D
o CD CD
cr
0 o —
o CD
;DI 0
0
CI) o �-
0,
cpn
'. co
a.
o
CD
cr
a.<o c
oO
o ocn
cn
is
° °
A, o
A,
- o
CD cp
0 0
o
CD
23 cn
o
v,
O.tion 1: Replace the four
Table 6-12
Initial Capital Costs (in millions of dollars)
existing motors and four
existing VFDs.
o
Option 2: Replace the four
existing motors and four
existing VFDs. Send blower
back to the manufacturer for
rebuild.
u,
4"
Option 3: Install three new
positive displacement
blowers with VFDs in a new
blower building.
i,,
"
Option 4: Install three new
single stage centrifugal
blowers in a new blower
building.
u,
°`
Option 5: Install three new
multistage centrifugal
blowers in a new blower
building.
6.2.7.4.3 Total Present Worth Costs
The following table shows the total present worth cost for each option. The results shown
in Table 6-14 are the sum of the initial capital costs from Table 6-12 and the present
worth energy costs in Table 6-13.
Table 6-14
Total Present Worth Costs (in millions of dollars)
Assumed Cost of Electricity
Annual Inflation Rate
Option 1: Replace the four
-xisting motors and four
-xisting VFDs.
Option 2: Replace the four
-xisting motors and four
-xisting VFDs. Send blower
• ack to the manufacturer for
ebuild.
O . tion 3: Install three new
is ositive displacement blowers
'th VFDs in a new blower
uilding.
Option 4: Install three new
single stage centrifugal blowers
. a new blower building.
Option 5: Install three new
multistage centrifugal blowers
in a new blower building.
0%
2.73
2.75
3.06
3.03
3.14
3%
3.62
3.64
3.91
3.75
3.98
6%
5.16
5.17
5.38
5.00
5.44
6.2.7.5 Discussion
Several key points should be noted after analyzing the results presented in Tables 6-12, 6-
13 and 6-14.
• Options 1 & 2 require the least investment of initial capital.
• Options 3 & 5 have moderate initial capital costs and moderate present worth
energy costs.
• Option 4 requires the most initial capital cost but is the most energy efficient.
Assuming 6% inflation in the cost of electricity, Option 4 has a total present worth
cost slightly less than Options 1 and 2.
While equipment costs and energy costs are somewhat easy to estimate, each option has
other considerations for which it is difficult to assign a dollar figure. Table 6-15
summarizes the pros and cons of each option.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-20
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 6-21
Table 6-15
Advantages / Disadvantages of Options
Options
Advantages
Disadvantages
Option 1:
•
Lowest initial capital cost.
•
Least energy efficient option.
Replace the
four existing
•
The existingblower room can be
•
Blowers are not rehabilitated and may
motors and four
existing VFDs.
re -used.
continue to have maintenance issues as
they near the end of their service life.
•
Removing the existing motors without
disturbing the existing facility and air
supply to the basins may be difficult.
•
Silencers will continue to be mounted
too far from the blowers, a possible
cause of resonance (excessive noise
and vibration) and therefore a need for
increased blower maintenance.
•
Coordination will be required with the
blower OEM regarding proper
selection of a motor and VFD.
•
PD blowers are noisiest blower option.
Option 2:
•
Low initial capital cost.
•
Least energy efficient option.
Replace the
four existing
•
The existing blower room can be
•
Removing the existing blowers and
motors and four
re -used.
motors without disturbing the existing
existing VFDs.
•
Blowers will be rehabilitated by
facility and air supply to the basins
Send blower
Gardner Denver and returned
may be difficult.
back to the
manufacturer
with a 90 day warranty on any
•
Silencers will continue to be mounted
for repairs.
repairs done.
too far from the blowers, a possible
cause of resonance (excessive noise
and vibration) and therefore a need for
increased blower maintenance.
•
Coordination will be required with the
blower OEM regarding proper
selection of a motor and VFD.
•
PD blowers are noisiest blower option.
Option 3: Install
•
Owner gets new blowers and a
•
Least attractive total present worth
four new
new 1 year warranty.
costs.
positive
displacement
•
Owner gets a new blower
•
PD blowers are noisiest blower option.
blowers with
building that is more convenient
•
PD blowers need to be belt -driven
VFDs in a new
for maintenance.
instead of direct drive in order to
blower building.
•
More energy efficient than
existing blowers.
operate at the rated point without
overspeeding the motor.
•
Moderate initial capital costs.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 6-21
6.2.7.6 Recommendations
Options 1 and 2 have the lowest initial capital costs and relatively low present worth
costs. However, there are many negative attributes to these options that could cause the
Owner to incur additional costs over a 20 year period.
Although it is difficult to estimate the service life of a blower, it is unlikely that any PD
blower installed in the existing piping system will last as long as a new blower installed
in a new building. The silencers in the existing piping system are not located close
enough to the blowers. For this reason, it is thought that a resonance condition causing
excessive vibration is occurring in the existing piping system. This excessive vibration
will likely reduce the service life of any new or rehabilitated blower installed in the
existing building.
The total present worth costs (assuming no inflation) for Options 3, 4 and 5 are all within
10% of each other.
Option 3 considers installing new PD blowers in a new blower building. The 400 hp PD
blowers would need to be belt -driven in order to operate at the rated point and avoid the
motor overspeeding condition. A belt -driven arrangement for this size blower is not an
attractive option. In fact, some blower manufacturers recommend against using belt
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-22
Table 6-15
Advantages / Disadvantages of Options
Options
Advantages
Disadvantages
Option 4:
•
Most attractive energy costs and
•
Most initial capital cost.
Install three
total present worth costs.
•
Maintenance staff has to become
new single stage
centrifugal
blowers in a
•
Ownergets new blowers and a
new warranty.
familiar with newtype of equipment.
new blower
building.
•
Owner gets a new blower
building that is more convenient
for maintenance.
Option 5:
•
Relatively low initial capital
•
Maintenance staff has to become
Install three
new multistage
cost considering that the Owner
familiar with new type of equipment.
centrifugal
gets a new building'
•
Energycosts about the same as PD
blowers in a
•
Owner gets new blowers and a
blower options.
new blower
new warranty.
•
Least attractive total present worth
building.
•
Owner gets a new blower
building that is more convenient
for maintenance.
costs.
•
Least noisy of the blower types
considered (hearing protection
probably still required).
6.2.7.6 Recommendations
Options 1 and 2 have the lowest initial capital costs and relatively low present worth
costs. However, there are many negative attributes to these options that could cause the
Owner to incur additional costs over a 20 year period.
Although it is difficult to estimate the service life of a blower, it is unlikely that any PD
blower installed in the existing piping system will last as long as a new blower installed
in a new building. The silencers in the existing piping system are not located close
enough to the blowers. For this reason, it is thought that a resonance condition causing
excessive vibration is occurring in the existing piping system. This excessive vibration
will likely reduce the service life of any new or rehabilitated blower installed in the
existing building.
The total present worth costs (assuming no inflation) for Options 3, 4 and 5 are all within
10% of each other.
Option 3 considers installing new PD blowers in a new blower building. The 400 hp PD
blowers would need to be belt -driven in order to operate at the rated point and avoid the
motor overspeeding condition. A belt -driven arrangement for this size blower is not an
attractive option. In fact, some blower manufacturers recommend against using belt
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-22
drives above 150 hp. For this reason, Option 3 is less attractive than the recommended
option. Additionally, the belt -driven blowers would likely be wider than the existing
direct drive units. The belt -driven PD blowers would probably not fit on the existing
equipment pads.
Option 5, installation of new multi -stage blowers in a new building, has the least
attractive present worth costs. The initial capital costs are relatively low but the energy
efficiency does not compare to the single stage blowers.
Option 4, installation of single stage blowers in_a_new__bLiilding,slh _ recQmmusid._
opti.on.. This option has slightly higher initial capital costs compared to the other options
but is by far the most energy efficient option. The savings that could be realized over a
20 year period make Option 4 the most attractive option for the Owner. A project cost of
$1.6 million is allocated for this option, which will be evaluated in greater detail during
preliminary and final design.
6.3 Disinfection Alternatives
Disinfection is provided to meet NPDES permit limits for fecal coliform bacteria. The
existing disinfection system consists of gaseous chlorine and gaseous sulfur dioxide for
de -chlorination. The existing disinfection system has sufficient capacity for average
annual conditions for year 2024. The system is now configured to have up to 12,000 lbs
of gaseous chlorine and 8,000 lbs of sulfur dioxide connected. Although the City has
developed their emergency action plan, and gas scrubbing systems are in-placejit the
storage facilities, personnel -and public safety and security concerns involved with the
handling of these gases require consideration of alternative methods of disinfection.
Several disinfection alternatives have been evaluated as part of this study.
6.3.1 Alternatives Considered
Six options have been examined for disinfection at the Yakima Regional WWTP. They
include:
• Maintain the existing chlorination/dechlorination system with minor retrofits
including a new baffle in each of the basins.
• Replace the chlorination system with hypochlorite/dechlorination with minor
retrofits including a new baffle in each of the basins.
• Replace the chlorination system with open channel low pressure ultraviolet light
disinfection.
• Replace the chlorination system with open channel low pressure — high output
ultraviolet light disinfection
• Replace the chlorination system with open channel medium pressure ultraviolet
light disinfection.
• Replace the chlorination system with closed channel medium pressure ultraviolet
light disinfection.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-23
Maintain Existing Chlorination/Dechlorination System
The current chlorination system consists of two chlorine contact chambers capable of
supporting the 2024 average annual design flow with an estimated contact volume of
808,000 gallons. Dechlorination follows the chlorine contact chambers prior to effluent
discharge to the Yakima River.
Under this alternative, the existing gaseous chlorination and dechlorination systems will
be retained for service. Minor modifications would be made, including modification of
the channel baffle to prevent short -circuitry of flows to the C2 pumping system,
installation of two additional chlorine scales (to ensure three scales for each of the two
manifolds in the chlorine tank room), and replacement of the Cl2 leak detector and the
SO2 residual analyzer.
Replace Chlorination System with Hypochlorite/Dechlorination System
Alternative wastewater disinfection methods have been used more frequently in recent
years due to safety and security issues, replacing traditional gaseous chlorine and sulfur
dioxide systems. As a result, liquid chemical systems using sodium hypochlorite as the
chlorinating agent and sodium bisulfite for dechlorination have become popular.
Liquid sodium hypochlorite and sodium bisulfite systems use different strategies for
chemical delivery, storage, metering, and injection than those commonly encountered
with gaseous chlorine and sulfur dioxide systems. Although sodium hypochlorite and
sodium bisulfite systems generally have fewer components and are less costly to construct
than gaseous systems, operators should have a thorough understanding of these systems
in order to make better decisions regarding chemical pumping options, materials, and
spill containment and safety features.
Sodium hypochlorite, a stronger version of liquid bleach, is a light -yellow liquid
oxidizing agent that is generally safer to handle than gaseous chlorine. Special handling
and storage issues are required. Sodium Hypochlorite is considered a chemical hazard
/hazardous waste during transportation.
Sodium hypochlorite is inherently unstable and loses about one-half of its strength every
100 days at 21°C (70°F). This strength loss increases as the temperature increases. The
rate of oxygen gas release as sodium hypochlorite solution degrades is of particular
importance to pumping and piping systems. Due to the off -gassing phenomenon, systems
can become "air locked" when gases accumulate at fittings and high points.
Required dosages of sodium hypochlorite are determined in the same manner that
chlorine dosages have been traditionally determined. Plant -specific testing usually is
required, since dosing requirements will vary at each site depending on the desired degree
of disinfection, available contact time, background interference (chlorine demand), and
other plant -specific variables.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-24
Sodium bisulfite generally is safer to use than gaseous sulfur dioxide and is equally
effective as a dechlorination agent. It does have its own unique characteristics that
require special handling considerations.
Sodium bisulfite is a clear to yellow liquid that reduces chlorine residual by the
oxidation-reduction reaction. Chlorine is not actually removed from solution by this
reaction but is reduced to an inert oxidation state.
Unlike sodium hypochlorite, sodium bisulfite does not degrade with temperature or time.
The concentration of sodium bisulfite is temperature dependent, which makes it prone to
crystallization.
Another special consideration for handling sodium bisulfite is the potential for sulfur
dioxide gas releases that can occur when the solution is heated or agitated. At plants
where sodium bisulfite off -gas scrubbers are not used, sulfur dioxide fumes generally
cause visible corrosion to adjacent structures and equipment and sometimes result in
odors or hazardous conditions.
Extreme caution should be taken to avoid mixing sodium hypochlorite with sodium
bisulfite solutions. The combination produces a violent exothermic reaction that can be
dangerous. Chemical loading stations should be clearly marked and separated, spill
containment lines should not be routed to a common drain, chemical piping should be
segregated, and storage tanks should not be located in the same secondary containment
basin.
Both sodium hypochlorite and sodium bisulfite are typically delivered in 5000 gal tanker
trucks.
Storage tanks typically are designed to hold a 15- to 30 -day supply of chemical during
average monthly flow conditions. Fiberglass reinforced plastic and cross-linked high-
density polyethylene (HDPE) are the two primary materials used for sodium hypochlorite
and sodium bisulfite storage tanks.
Because the chemicals are potentially hazardous materials, fire codes require that
safeguards be incorporated in the design to control possible spills resulting from a tank
rupture or pipe break. Tanks, pumps, and piping must be located inside a secondary
containment basin that can hold the contents of one full tank and 24 hours of rainfall.
Three types of chemical metering systems are commonly used for sodium hypochlorite
and bisulfite systems: diaphragm metering pumps, centrifugal pumps, and eductors.
Diaphragm metering pumps are the most prevalent method for dosing sodium
hypochlorite and sodium bisulfite.
Piping for sodium hypochlorite and sodium bisulfite generally is made of Schedule 80
polyvinyl chloride (PVC) or Schedule 80 chlorinated polyvinyl chloride (CPVC).
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-25
Ball valves or diaphragm valves are recommended on sodium hypochlorite and bisulfite
lines.
Sodium hypochlorite and bisulfite systems use the same control strategies as chlorine and
sulfur dioxide systems. Control systems can employ traditional feed forward, feedback,
or compound loop strategies.
To implement this alternative, the existing chlorination and dechlorination systems would
be removed. The space available in the chlorine storage area would be converted to
hypochlorite storage, and the sulfur dioxide storage area would be converted to sodium
bisulfite storage. New pumping and piping systems, containment systems, flash mixing
systems, and monitoring, reporting and control systems would be installed. As in the
previous alternative, modifications of the channel baffle system to prevent short-
circuiting of flows to the C2 pumping system would be required.
UV Disinfection Alternatives
A wide range of low pressure ultraviolet light equipment for wastewater effluent
disinfection are available. These systems are typically easy to install and operate, and
normally come complete with their own integral controls. A general ultraviolet
disinfection process layout is shown in Figure 6-5. For evaluating the available
disinfection alternatives, it is anticipated that the systems would be configured to
accommodate the ultimate build -out conditions of 39.2 mgd. This would include channel
modifications and other capital improvements required for the ultimate condition. For
determining present worth of annual operation and maintenance costs, the average flow
condition of 15.5 mgd (Year 2024 flow condition) is utilized.
Figure 6-5. Ultraviolet Disinfection Alternatives
PRIMARY CLARIFIERS TRICKLING FILTERS
T
Y
1 THE BAFFLES WILL BE REMOVED FROM THE CHLORINE CONTACT CHAMBERS
PRIOR TO THE INSTALLATION OF ULTRAVIOLET DISINFECTION
AERATION BASINS SECONDARY CLARIFIERS ULTRAVIOLET
DISINFECTION
l YAKIMA
RIVER
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-26
Replace Chlorination System with Open Channel - Low Pressure Ultraviolet Light
Disinfection
This alternative would include removal of the gaseous chlorination and dechlorination
systems, and retrofit of the hypochlorite feed to the air emissions control system. The
space made available in the chlorination and dechlorination feed and storage areas would
be made available for other treatment plant needs. The existing redwood baffle systems
would be removed, and concrete walls and access grating would be installed within the
basins to accommodate installation of the ultraviolet light lamp basins. A vertical lamp
arrangement would be utilized. Two parallel UV channels would be installed, each with
a peak flow capacity of approximately 20.0 mgd. Level control facilities, lamp removal
hoists and monorails, and lamp cleaning systems would be installed. A portion of the
existing chlorine storage room could be used for UV lamp maintenance and cleaning
purposes, and for installation of the UV electrical services equipment. A building would
be installed over the UV channels to provide for weather protection for equipment
maintenance. Low pressure ultraviolet bulbs have the ability to treat up to 23 gallons per
minute per lamp of wastewater. Based on average transmissivities that would be
encountered at Yakima, an estimated 1,122 low pressure lamps would be required to
handle the peak flow condition of 39.2 mgd at buildout. UV vendors are indicating that
these systems are no longer going to be supported and therefore in five years, parts may
be difficult to obtain.
Replace Chlorination System with Open Channel - Low Pressure High Output
Ultraviolet Light Disinfection
Similar to the low pressure ultraviolet light alternative, this option would remove the
existing gaseous systems and replace them with low pressure ultraviolet light equipment.
The contact basin redwood baffle systems would be replaced with concrete divider walls
to accommodate the low pressure — high output ultraviolet light system. Low pressure —
high output ultraviolet lamps are capable of treating greater amounts of wastewater per
lamp. A single low pressure high output lamp can treat up to 60 gallons per minute per
lamp, significantly greater than low pressure lamps. As a result, only approximately 440
low pressure -high output lamps would be required to accommodate the ultimate build -out
peak flow condition of 39.2 mgd. A horizontal alignment was utilized for costing
purposes. Two parallel UV channels would be installed, each with a peak flow capacity of
approximately 20.0 mgd. Level control facilities, equipment protection building, and a
jib crane for module maintenance would be provided. These systems are fabricated with
automatic cleaning equipment. Therefore, the external cleaning system provided for the
low pressure system is not required. Similar to the low pressure alternative, a portion of
the chlorine storage room could be dedicated for maintenance and electrical service
purposes.
Replace Chlorination System with Open Channel - Medium Pressure Ultraviolet
Light Disinfection
Similar to the low pressure ultraviolet light alternative, this option would remove the
existing gaseous systems and replace them with medium pressure ultraviolet light
equipment. The contact basin redwood baffle systems would be replaced with concrete
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-27
divider walls to accommodate the medium pressure ultraviolet light system. Medium
pressure ultraviolet lamps are capable of treating greater amounts of wastewater per lamp.
A single medium pressure lamp can treat up to 300 gallons per minute, significantly
greater than low pressure lamps. As a result, only approximately 100 medium pressure
lamps would be required to accommodate the ultimate build -out peak flow condition of
39.2 mgd. One UV channel would be installed with a peak flow capacity of
approximately 40.0 mgd. Level control facilities, equipment protection building, integral
hoist systems, and lamp cleaning and maintenance systems would be provided. Similar to
the low pressure alternative, a portion of the chlorine storage room could be dedicated for
maintenance and electrical service purposes.
Replace Chlorination System with Closed Channel - Medium Pressure Ultraviolet
Light Disinfection
This alternative would also include removal of the existing chlorination and
dechlorination systems. The closed channel technology requires directing wastewater
flows via pipeline through enclosed chambers installed on these pipelines. To
accommodate the closed channel technology at Yakima, it has been anticipated that three
parallel flow pipelines (two duty, one back-up) would be installed in the existing chlorine
contact basin. This would serve as an ultraviolet lamp gallery and would be accessible
from ground level. The gallery would be configured with drainage systems to maintain
the gallery dry, overhead hoist, and access stairs would be added for equipment and
personnel access. Equipment protection building, integral hoist systems, and lamp
cleaning and maintenance systems would be provided. The existing chlorine storage
room could be used for required electrical service equipment associated with the
ultraviolet light systems. Control valves and system automation would be installed to
bring the multiple parallel systems on line as required by the plant flow conditions.
6.3.2 Alternatives Evaluation
• Based upon projected flows and loadings presented in Section 5, the chlorine
contact channels have sufficient capacity to year 2024 average annual flow
conditions of 15.5 mgd, and peak flow conditions of 32.9 mgd. The existing
chlorine contact channels require some retrofits. There is growing public concern
dealing with the safety of liquid and gas chlorine. Security issues related to the
use of chlorine are becoming more of a concern for utilities.
• Evaluation of alternatives will address the ultimate build -out condition of 39.2
mgd for capital costs. Operation and maintenance evaluation is based on year
2024 conditions.
• Traditional low pressure UV systems are ideal for low flow wastewater
disinfection on smaller projects, but units for larger wastewater disinfection
applications are also available. As flows increase, or higher UV doses are
required, multiple low pressure lamps are used. Due to the operational issues
related to cleaning of the quartz sleeves, traditional low pressure UV systems
typically are no longer used and are being phased out.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-28
• Low pressure UV systems offer cost savings with lower power requirement when
compared to medium pressure systems. These systems also are equipped with
automatic cleaning systems.
• Medium pressure UV systems offer some simplicity in layout. This results in cost
effectiveness while meeting the high flow/high dose challenge. Medium pressure
systems offer advantages such as fewer lamps to install and maintain, operational
flexibility, easier expandability, and a self-cleaning capability. The small number
of lamps required for medium pressure systems also lead to problems associated
with redundancy at peak flow rates.
• Medium pressure enclosed channel systems would require less modifications to
the existing contact channel for installation. This would be offset by the
additional stand by unit that would be required to maintain capacity during
maintenance activities.
• There are greater operation and maintenance requirements associated with
maintaining the low pressure open channel systems due to the large number of
lamps associated with the design.
• Implementation of either the open channel low pressure high output or medium
pressuresystems is easier than low pressure systems because less channel
modifications and infrastructure improvements are required.
• Maintenance, operation, and energy consumption costs are similar for open
channel and enclosed channel medium pressure systems.
• The City would improve site safety considerably by removing the large quantities
of the gaseous chlorine and sulfur dioxide feed systems. In addition to reduction
in the risks associated with handling and transport of hazardous chemicals, the
truck traffic to the wastewater treatment plant would be reduced by installing UV
equipment.
Opinions of probable cost were developed for each of the disinfection alternatives. These
are summarized in Table 6-16. These estimates are based on initially providing the
capacity needed for year 2024 and then expanding the facility for ultimate peak flow
conditions of 39.2 mgd. Initial channel modifications are sized to accommodate
installation of the equipment for ultimate conditions.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-29
Table 6-16
Opinion of Probable Cost and Present Worth Analysis for Disinfection Alternatives
Unit
Opinion of Probable Cost (to Build -out)
Maintain
Existing
Chlorination
System
Hypochlorite/
Bisulfite
Open
Channel
Low
Pressure
Open
Channel
Low
Pressure -
High
Output
Open
Channel
Medium
Pressure
Closed
Channel
Medium
Pressure
Facility Construction
and Retrofits
$149,000
$277,000
$1,205,000
$1,120,000
$1,280,000
$1,500,000
Electrical (15%)
$22,000
$42,000
$181,000
$168,000
$192,000
$225,000
I/C (7 %)
$10,000
$19,000
$85,000
$78,000
$90,000
$105,000
Site Work and Yard
Piping (20%)
$30,000
$55,000
$241,000
$224,000
$256,000
$300,000
Subtotal Costs
$211,000
$393,000
$1,712,000
$1,590,000
$1,818,000
$2,130,000
Contingency (30%)
$63,000
$118,000
$514,000
$477,000
$545,000
$639,000
Subtotal
$274,000
$511,000
$2,226,000
$2,067,000
$2,363,000
$2,769,000
Engineering, legal and
administration (25%)
$69,000
/ -�
$128,000
$557,000
$517,000
$591,000
$692,000
Total Opinion of
Probable Construction
Cost
(
$343,00\
$639,000
$2,783,000
$2,584,000
$2,954,000
$3,461,000
Annual Operation and
Maintenance Cost
$87,000
$218,000
$175,000
$133,000
$153,000
$170,000
Present Worth of
Operations and
Maintenance
$1,084,000
$2,717,000
$2,181,000
$1,657,000
$1,907,000
$2,119,000
Total Alternative
Present Worth Cost
$1,427,000
$2,935,000
$4,964,000
$4,241,000
$4,861,000
$5,580,000
The results of Table 6-16 illustrate a cost savings associated with retaining the existing
chlorination and dechlorination systems. The annual operation and maintenance costs are
presented as a total present worth value based on a design life cycle of 20 years and
projected annual interest rate of 5 percent. In developing the operation and maintenance
costs, unit costs consistent with values previously presented were used. Gaseous chlorine
costs were estimated at $0.20/lb, sulfur dioxide costs were estimated at $0.31/1b,
hypochlorite costs were estimated at $0.55/1b, bisulfite costs were estimated at $0.43/lb,
and 3 percent was added for miscellaneous materials.
In terms of total present worth cost, retaining the existing chlorination and dechlorination
systems is clearly cost effective. The hypochlorite/bisulfite alternative also appears to be
cost-effective in terms of capital costs, but annual operations and maintenance cost is the
highest among the alternatives considered. The total present worth costs for all the
ultraviolet light alternatives are similar, with the open channel low pressure high output
system having a slight advantage in overall present worth cost.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-30
6.3.3 Recommendations
Maintaining the existing dual channel gaseous chlorination system provides a cost
effective means for disinfection of the Yakima Regional WWTP effluent. Because this
alternative involves the least change to existing infrastructure, it is also the easiest to
implement.
However, there is a significant non -economic impact and unaccounted-for (in this cost
analysis) economic impact associated with the gaseous chlorine disinfection alternative.
Handling of the hazardous gases in close proximity to commercial areas and the interstate
highway poses a significant health and safety risk, and administrative challenge
complying with regulatory requirements. Security and vulnerability are also issues that
the City will have to consider now and in the future. The decision to retain the existing
disinfection facilities or switch to a new technology considered many of the issues
depicted in Figure 6-6 rather than based solely on estimated alternative cost.
Transco ttance
Number
of
Systems
TDS Installed,
\ Bacteria
Water ` Sotdis
Quefliy,
Demostration
Study —� Specific
Application
Installed Experience
Systems
Capacity
of
Systems
Chemicals
Power
Modeling
Hydraulics Peak
_ _AUM F
Labor Demand / Flower
Charge/
l/
Operations
Cost
Wastewater
Experience
End
Construction Use
Cost
Lite
ycle
Type of Ease of _-
Reactor Cleaning Space Equi ment
f
Stan Equipment
Complexity
Type of of Cleaning Ease of e
Cleaning Time
-S stem Maintenance
system Simple
Reactor
Procedures
Start
up Chemical
System Equipment time Storage
Access
Chemical
Safety
Training
isk/- Accidental
Release
Other
Equipment
Access Control
Reactor
Size
By-products
Figure 6-6. Non -economic Criteria for Selection of Disinfection System
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 6-31
Maintaining the existing chlorine contact basin, while replacing the
chlorination/dechlorination system with sodium hypochlorite and sodium bisulfite,
appears to have some initial cost savings. The annual operations and maintenance cost
for this alternative are approximately three times greater than the present system.
Chlorine application for fecal coliform kills is based on application dosages averaging
1.40mg/I for sodium hypochlorite to 1.00 mg/l for chlorine gas. Approximately 1.60 mg/1
of sodium bisulfite is needed to neutralize 1.00 mg/I of chlorine. The annual cost of
hypochlorite use is anticipated to be three times greater than chlorine gas, and can vary
considerably based on the cost of individual chemical used to manufacture the chemical.
The annual cost of bisulfite use is anticipated to be two to three times greater than dioxide
gas. Both sodium hypochlorite and sodium bisulfite present a safety risk for skin burns
and/or eye injuries from splashing or spilling. Sodium hypochlorite is classified as a
hazardous chemical due to the pH of the solution being greater than 12.5.
Although ultraviolet light disinfection will cost more initially, and has a higher present -
worth cost in the analysis, the technology reduces the risk and administrative effort of
operating with hazardous chemicals, provides an easily expandable system if additional
disinfection is required, reduces operation and maintenance activities, and reduces the
risk of discharging hazardous chemicals or byproducts to the river.
Medium pressure UV systems have a slight initial cost advantage, but low pressure — high
output systems offer an operations and maintenance advantage. Due to plant electrical
distribution considerations and typical application size, it is recommended that low
pressure- high output systems be considered for implementation.
6.4 Air Emission Treatment Technology Review
Air emissions that are typically emitted from domestic wastewater collection and
treatment processes include both inorganic gases, such as hydrogen sulfide and ammonia,
and organic gases and vapors. The following discussion reviews the available options for
control of odorous air emissions.
6.4.1 Atmospheric Dispersion
Gases may be collected and dispersed into the atmosphere, relying on natural dilution to
lower air emission concentrations. Increasing stack height, increasing stack exit velocity,
and adding dilution air to the emissions can increase dilution rates. The main drawbacks of
this method are the aesthetic impacts of a stack, as well as the unpredictable nature of
atmospheric dilution.
6.4.2 Air Emission Modification
The effectiveness of modification agents for eliminating, or reducing, air emissions is a
subject of continuing debate. Modification involves the release of another material that
reacts with the air to form a non -odorous or pleasant -smelling emission. Counteracting
agents are similar to, and may be included as part of, a modification agent mixture.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 6-32
Counteraction refers to the reduction of a specific air emission through the proportional
addition of a non -chemically reactive agent. Examples of pairs of gases, and their
respective counteraction are: ethyl mercaptan and eucalyptol, skatole and coumarin, butyric
and juniper oil.
Modification agents have met with variable success at wastewater treatment plants. They
are often applied as interim solutions, or for short duration during periods of air emissions.
In general, modification cannot be relied upon as a long term solution. Air emissions from
a process can escape without treatment because of the difficulty of achieving a wide
coverage of the chemical agents. There is no containment of the air emission or the
chemical agents to insure adequate contact and mixing time prior to release. Also, there
will probably always be a certain number of individuals who find the modification agent
offensive in itself. This option was not considered further as a long term solution to
potential air emissions at the treatment plant.
6.4.3 Liquid Phase Treatment
Air emission reduction can be accomplished by chemically or biologically altering the
characteristics of the wastewater as it enters the treatment facility. Some or all of the
following methods can reduce the air emission potential of wastewater.
6.4.3.1 Chemical Addition
Chemicals may be added within the treatment plant to oxidize or precipitate air emission
compounds. Commonly used chemicals include chlorine, hydrogen peroxide, potassium
permanganate, and iron salts.
Chlorine is a chemical oxidant with the reactive component being the hypochlorite ion.
Chlorine is highly reactive and will react with many compounds found in wastewater
including H2S. Chlorine indiscriminately oxidizes any reduced compound in wastewater.
As a result, to ensure sulfide oxidation, overfeeding of chlorine from 5 parts to 15 parts
by weight of chlorine to one part sulfide is required. Chlorine will act as a bactericide
and will kill or inactivate bacteria in the air emissions. It can also kill organisms
beneficial to the activated sludge treatment process. Since chlorine is considered to be a
potentially hazardous material its release into the collection system or into the wastewater
treatment facility in the large quantities required to oxidize air emission compounds is not
recommended.
Hydrogen peroxide oxidizes H2S to elemental sulfur or sulfate compounds and requires 1
to 3 parts per one part of sulfide. Its reaction with sulfide and other air emission causing
compounds usually yields harmless byproducts with the excess hydrogen peroxide
decomposing into water and oxygen. Hydrogen peroxide will only control air emissions
for a short period of time, and because it is very reactive with organic materials, the
maintenance and operation of hydrogen peroxide systems require special training,
maintenance, operational procedures, and safety practices. Hydrogen peroxide is not
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-33
recommended for long term air emission abatement within a wastewater treatment
facility.
Potassium permanganate (KMnO4) is a solid chemical that is generally considered too
expensive for treating sulfide in bulk liquid flows such as influent flow to the primary
settling tanks. Typical dosage rates for treating influent liquid can be as high as 5:1.
Iron salts react with sulfide to form insoluble precipitates and are widely used for control
of sulfide at wastewater facilities. Both ferric and ferrous chemicals provide effective
sulfide control, but ferric chloride also enhances primary settling and reduces downstream
process loadings. The use of the ferric chemical will also reduce phosphorous. The
lowest treatment costs are usually obtained by purchasing the product from a local
supplier to minimize transportation costs. One advantage of iron salts over oxidation
chemicals is that the salts do not react with wastewater organics and they are fairly
sulfide -specific. Effective treatment has been obtained with an iron -to sulfide dosage rate
of 3.5 lb/lb.
6.4.4 Vapor -Phase Treatment
Vapor -phase treatment differs from liquid phase treatment by treating the air rather than
reducing the potential of the wastewater to produce air emissions. Gas phase treatment
involves the capture, as well as the processing, of the volatilized compounds present in
wastewater. This phase of treatment may involve the oxidation, reduction, or
modification of the volatilized compounds to a state where they are no longer detectable
or perceived as unpleasant.
6.4.4.1 Activated Carbon
Activated carbon is used to remove pollutants by surface adhesion. The highly porous
structure of the carbon supplies a large surface area per unit volume. Systems typically
consist of a stainless steel or fiberglass vessel containing a single bed or dual beds of
granular activated carbon through which the odorous air is discharged. Conventional
carbon units are sized for face velocities of 50 feet per minute and typically use a media
depth of 3 feet. Because activated carbon is non -polar, water molecules, which are highly
polar, are not attracted to the sites, benefiting the use of activated carbon in treating
wastewater air streams which are often high in humidity.
The four main types of carbon media available are virgin, caustic impregnated, Centaur,
and Midas carbon. Virgin carbon has high VOC capacity, but low H2S capacity. Caustic
impregnated carbon has better H2S capacity, but a diminished ability to remove other
odorous compounds. Caustic carbon can be chemically regenerated in-situ, but this
requires handling of hazardous chemicals, so caustic carbon is not recommended for this
application. Centaur carbon is a proprietary product from Calgon that can be regenerated
multiple times with water. For example, at 10 ppm H2S, the Centaur carbon would
require regeneration every six months. Midas carbon is produced by U.S. Filter and has a
very high H2S removal capacity as well as other odorous compounds. Based on life -cycle
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-34
costs Midas is about the same cost as Centaur and the replacement life is about equal,
with no need to regenerate. The chief advantage of activated carbon systems is the
simplicity of these systems relative to other control technologies.
6.4.4.2 Packed Tower Liquid Scrubbing
Packed tower liquid scrubbers absorb compounds into the liquid phase where they can be
quickly oxidized by sodium hypochlorite, chlorine, hydrogen peroxide, or other oxidant.
This is the control technology currently employed at the Yakima Regional WWTP
facility. Liquid scrubbing technology is well established, and proven highly effective for
removing sulfide and other gas, when used with an oxidant as described.
Packed towers are usually cylindrical towers constructed of fiberglass or other corrosion -
resistant material and containing a bed of plastic or ceramic packing material. Scrubbing
liquid (high pH, high oxygen reduction potential) is sprayed or distributed over the top of
the packing media and flows down through the bed, coating the packing with a thin layer
of liquid. Air flowing upward through the media is scrubbed; the air passes through a
mist eliminator, and exits the top of the scrubber. The scrubbing liquid collects in a sump
at the bottom of the tower, and a certain amount is wasted when new chemicals are added
to maintain the desired pH and ORP. The wasted chemical could be returned to the
headworks.
As a significant amount of scrubbing liquid is readily available to treat peaks and spikes
in the air to be treated, packed towers have a significant advantage over atomized mist
scrubbers. Peaks will not deplete the absorption and oxidation potential of the scrubbing
liquid before the change in strength of the solution is detected by the scrubber controls
and new chemical can be added.
Packed tower liquid scrubbing is commonly used for air sources at wastewater treatment
facilities. Yakima's treatment system, illustrated in Figure 6-7, has two packed tower
systems installed on the ventilation exhaust air from the trickling filters. Potential air
emissions from several source areas are directed to the trickling filters where the air is
passed through the trickling filter media prior to discharge to the packed tower treatment
units. Some oxidation of air compounds within the air stream occurs within the trickling
filters prior to delivery of this air to the packed towers. Because the required_airvo.lume
for proper operation of the trickling filters_ex,ceeqs the volume of air currently collected
from the potential air sources, outside make-up'air is required at the trickling filters. As a
result, there appears to be reserve capacity within the existing system to direct additional
air sources to the trickling filter units.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 6-35
Figure 6-7. Yakima's Air Emission Treatment System
6.4.4.3 Biofilter
Biofiltration is a biological process using soil, compost, or other media as a substrate for
microbes that remove odorous contaminants from an air stream as it travels through the
media. Sufficient residence time must be provided for microbes to accomplish effective
contaminant treatment, so biofilters must use a low air velocity. For H2S removal, typical
residence times range from 40 seconds to 60 seconds. Longer residence times may be
necessary for airstreams containing high concentrations. Because the biodegradability of
compounds differs, some compounds require several minutes of residence time for effective
removal. Biofilters can also be designed to remove odorous VOCs and specific
compounds.
The key elements in biofilter design are media, air distribution, and moisture. Biofilter
media can be composed of organic materials, such as wood chips, compost, soil, peat moss,
or some combination of these. Improper media can compact or become too wet, whereas a
properly formulated media will last longer. Media porosity is itnportant to minimize the
head loss in the bed. Bed depths are typically 3 to 5 feet with face velocities of 2 to 8 fpm.
The low velocity results in very large footprint. Organic biofilter media degrades during use
and must be replaced. The Life cycle is dependent on contaminant concentration, but
typically ranges from 2 to 3 years. Inorganic media now available through several vendors
has a longer life. BIOREM provides engineered biofilter systems with BIOSORBENS
media, an inorganic media with a 10 -year media life. This media is approximately three
times the cost of organic media, but provides a much longer life cycle.
Good air distribution through the biofilter media is an essential element of biofilter design.
If air distribution is uneven, treatment will be inconsistent and channels can develop,
allowing air to escape untreated. Many designs employed a low cost network of perforated
pipe embedded in gravel, but some of these systems have had poor distribution. Recent
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-36
improved designs use manufactured distribution blocks or ceramic media. A well-designed
distribution system should provide even airflow with a minimum of pressure loss.
Another key parameter influencing the effectiveness of biofilters is moisture content.
Biofilters must operate at a moisture content consistent with the requirements of microbial
life. Proper moisture content also prevents media drying and cracking, which allows the
escape of untreated odors. Well designed biofilters employ some means of adding
moisture, either to the airstream, to the media internally, or to the top surface of the media.
In some cases, control equipment is installed to sense the moisture content of the biofilter,
and automatically increase moisture as needed. Fine mist systems have had problems with
nozzle scaling. Some new designs employ a coarse spray, which also allows for
maintaining temperature with a water heating device.
Due to their larger size and labor-intensive construction, biofilters can cost significantly
more to build than wet scrubbers or activated carbon units. The higher initial costs may be
offset by lower operational costs, depending on the H2S concentrations being treated.
6.4.5 Unit Processes Which Have Potential Sources of Air Emissions
Release of air emissions from wastewater is generally caused by turbulent conditions that
may result in the volatilization of compounds. Table 6-17 presents the unit processes at
the Yakima Regional WWTP, their air emission potential, and whether the unit process is
currently enclosed and the ventilated air is treated.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-37
Table 6-17
Air Emission Potential from Unit Processes
Unit
Process
Potential
Enclosure
Screenings
Area
Potential air emissions from the screened
materials that are removed from the
incoming wastewater during the dewatering
process.
Screenings Building constructed in
1998 and is completely enclosed with
the air routed to the trickling filters and
then the packed towers for scrubbing.
Grit Removal
Air emission potential is minimal as there
are no turbulences.
All channels from the screening area to
the grit area were covered during 1998
construction and air is drawn from the
screening building through the channels
and then routed to the trickling filters
and packed towers.
Parshall Flume
Channel.
Air emission potential as some turbulences
may be present.
Not enclosed
Primary
Clarifier
Influent
Channel
Air emission potential is minimal as there
are no turbulences.
Not enclosed
Primary
Clarifiers
These units have air emission potential at
the influent well where the wastewater is
first introduced into the tankage and then
again as the water flows over the effluent
weirs. Both of these introduce turbulences
into the flowing water.
Not enclosed
Trickling Filter
Pump Station
This area has a moderate air emission
potential as the wastewater is pumped to the
trickling filter units.
Wet well is enclosed and ventilated.
Air is routed to trickling filters.
Trickling
Filters
The air emission potential in these units is
caused by the wastewater cascading over
the rocks.
Units are covered and air is forced
down through the rock media where it
receives biological treatment and then
is routed through the packed towers.
Trickling Filter
Clarifier
Effluent Pump
Station
Air emission potential is from trickling
filter effluent and trickling filter clarifier
effluent.
Not enclosed
Aeration
Basins
Air emission potential is minimal in these
units due to the aerobic (high oxygen
content of the wastewater) process. New
high efficiency air diffusers were installed
in 1989.
Not enclosed
Return
Activated
Sludge
Pumping
Station
Air emission potential in this area is caused
by the cascading of the return activated
sludge from the secondary clarifiers to the
aeration basin.
Screw pumps enclosed.
Secondary
Clarifiers
Minimal air emission potential as the water
at this point in the process is rich in oxygen.
Not enclosed
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 6-38
Chlorine
Contact Basins
Minimal air emission potential as the water
at this point in the process is rich in oxygen
and has a chlorine residual.
Not enclosed
Dissolved Air
Flotation Unit
Air emission potential is from the
volatilization of material in the thickening
of waste activated sludge.
Unit is enclosed and ventilation air is
routed to Trickling Filters and packed
tower scrubbers.
Primary
Digesters
Air emission potential is from the escape of
biogas.
All the primary digesters were
rehabilitated and either coated with a
polyurethane coating or lined with a
PVC liner during the 1998 construction
project.
Secondary
Digesters
Air emission potential is from the escape of
biogas.
Secondary digesters were rehabilitated
with a polyurethane liner, and the
floating and fixed covers were replaced
with a dual reinforced thermoplastic
vinyl cover.
Solids
Handling
Building
Air emission potential is from the
centrifuging operation of biosolids.
Facility is enclosed and centrifuge has
separate air ducting which is routed to
Trickling Filters and Scrubbers.
Lagoon
Air emission potential is from storage and
discharge of centrifuge centrate.
Not enclosed
6.4.6 Review of System Strategies
The following paragraphs provide a review of the remaining process unit areas within the
facility that are open to the atmosphere and may be potential sources for air emissions.
6.4.6.1 Parshall Flume and Primary Clarifier Influent Channel
These channels have a potential to release air emissions since there is turbulence as the
wastewater passes through the flow measurement flumes on its route to the primary
clarifiers. Covering these channels could effectively reduce release of air emissions in the
vicinity of the Influent Building. Ventilation air from this area could be routed to an odor
control unit for treatment.
6.4.6.2 Primary Clarifiers
The overflow weirs on the primary clarifiers are turbulent and are a potential source of air
emissions. Covering these weirs and treating the air will reduce the potential of this air
emissions source. Figure 6-8 illustrates typical weir and launder covers for circular
clarifiers.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-39
Figure 6-8. Typical Weir and Launder Covers
Covering the entire primary clarifier surface is another option. It would result in the
capture of all air emissions from this system, including the influent well. As with the
influent channel, ventilation air from this area could be routed to an odor control unit for
treatment.
6.4.6.3 Return Activated Sludge Pumping Station
Volatilization of organic compounds can occur as the return activated sludge (RAS) is
pumped from the secondary clarifiers to the aeration system by the existing screw pump
system. The screw pumps are already covered. Enclosing the rest of the area would
reduce the air emissions from the RAS pumping station. As with the other unit processes,
ventilation air would be ducted to an odor control unit for treatment.
6.4.6.4 Trickling Filter Clarifier Effluent Pump Station
Odors have been reported to be an issue at this structure, which receives effluent from the
trickling filters and the trickling filter clarifier. As with the other unit processes,
enclosing this structure and sending the air to an odor control unit for treatment could be
considered.
6.4.6.5 Secondary Clarifiers
The potential for air emissions from these units is slight as the wastewater at this stage in
the process is high in dissolved oxygen. Odor control will not be considered for the
secondary clarifiers.
6.4.6.6 Aeration Basin/Chlorine Contact Basin
At both of these unit process operations, the potential for air emissions is minimal. The
wastewater is high in oxygen content, and at the chlorine contact basin contains a chlorine
residual slightly higher than is found in tap water. These unit processes are seldom
covered at wastewater treatment plants, and are not considered as a source of odorous air
emissions.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-40
6.4.6.7 Lagoons
The north lagoon has been permanently taken out of service. The City has discontinued
the use of the south lagoon for storage of digested solids. Centrifuge centrate, which is
high in ammonia concentration, continues to be discharged to the south lagoon. The
lagoon was alleged as a possible source of odor through ammonia release.
6.4.7 Opinion of Probable Costs
Table 6-18 presents the opinion of probable costs for construction of covers for each of
the options described above, and also presents the present worth of the O&M costs based
on a 5 percent discount rate for 20 years. The total present worth costs shown represents
a total of the opinion of probable cost and the present worth of the O&M costs. The range
of costs for each individual element are cumulative, except that covering of the complete
primary clarifiers would not require covering the primary clarifier centerwell and weirs
individually. Further evaluation is required before an expenditure of any remediation
item is recommended.
Olinion
Table 6-18
of Probable Cost of Control Improvements
Item Description
Parshall
Flume and
Primary
Clarifier
Influent
Channel
Primary
Clarifier
Launder
Covers
(Four)
Primary
Clarifier
Covers
(Four)
RAS
Pumping
Station
Covers
Trickling
Filter
Clarifier
Effluent
Pump Station
Cover
Facilities'
$50,000
$400,000
$600,000
$55,000
$65,000
Site Work @20%
$10,000
$80,000
$120,000
$11,000
$13,000
Subtotal
$60,000
$480,000
$720,000
$66,000
$78,000
Contingency @ 30%
$18,000
$144,000
$216,000
$20,000
$23,000
Subtotal
$78,000
$624,000
$936,000
$86,000
$101,000
Engr/Legal/Admin @
25%
$20,000
$156,000
$234,000
$22,000
$25,000
Total Opinion of
Probable Cost
$98,000
$780,000
$1,170,000
$108,000
$126,000
Operations and
$10,000
$22,000
$91,000
$10,000
$10,000
Present Worth of
$125,000
$275,000
$1,138,000
$125,000
$125,000
Total Present Worth
$223,000
$1,055,000
$2,308,000
$233,000
$251,000
I Facilities cost for covers and new odor control scrubbers include ductwork/piping and electrical.
6.4.8 Recommendations
Since 1989, the Yakima Regional WWTP has continued on a program to reduce the
potential for releasing air emissions from the wastewater treatment facility. During each
improvement and expansion contract, areas that had a potential for releasing odorous air
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 6-41
emissions have been covered and ventilated to capture and treat the odorous air. If unit
processes or specific areas within the facility are expected to produce odorous air
emissions, or if the facility begins _to re .ve odor complaints, then these areas should be
evaluated in greater detail to determine the most cost-effective method to reduce and treat
the odorous air.
6.5 Wastewater Treatment Plant Operations, Maintenance and
Support Programs
In order to assure proper treatment and compliance with the plant's NPDES permit limits
and requirements, it is essential to provide a proper level of qualified operations,
maintenance, laboratory, administrative and support personnel. Other requirements
include implementation of a maintenance management system to assure proper and timely
maintenance of all mechanical, instrumentation and control systems, and implementation
of an Industrial Pretreatment Program in accordance with the legal authorities, policies,
procedures and financial provisions as described in the "Industrial Pretreatment Program"
as submitted to and approved by the Washington State Department of Ecology.
Additionally similar requirements exist for the proper operation and maintenance of the
collections system serving the facility, along with establishing intergovernmental
agreements with surrounding communities operating satellite collections systems. In
doing so the Yakima Regional WWTP endeavors to satisfy the legal and administrative
requirements of federal and state agencies, to conserve the financial investment by the
community in constructing the facilities, to maintain the environment of the community,
to provide for the health and safety of the citizens of the community, and to protect the
surface and ground water of the Yakima Valley.
The following discussion summarizes the current staffing of the facility including
operations, maintenance, laboratory, pre-treatment, and support personnel. Additionally,
the status of programs such as the Pretreatment program (fully delegated to the City of
Yakima) and the current maintenance management system are described.
6.5.1 Operations and Maintenance Staffing
Operations staff at the Yakima Regional WWTP provide for the continuous day to day
function of all treatment and solids handling systems. Of paramount importance is the
responsibility to ensure compliance with the NPDES permit requirements. In staffing the
facility, the City of Yakima has ensured compliance with the operator certification
requirements of the NPDES permit, as outlined in Part S5.A, Certified Operator. As
required, an operator certified for a Class IV facility, acting as Process Control Supervisor
oversees the day-to-day operations of the treatment plant. Additionally, an operator
certified, at a minimum, for a Class III facility oversees all scheduled shifts. At the
present time the facility is staffed 24 hours a day by three separate shifts. The current
staffing level of the facility is shown in Table 6-19.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-42
Table 6-19
Current Operations Staffing Levels
Job Title
Minimum
Certification Level
Number of Full
Time Equivalents
WWTP Process Control Supervisor
Class IV
1
WWTP Chief Operator
Class III
4
WWTP Operator III
Class III
8
WWTP Operator II / I
See Note 1
6.58
Facility Support Worker
-
1.58
Total Operations Staffing
21.16
Note 1- Operator -I must possess an OIT certification within 6 months of appointment. Operator -II must
have an OIT certification, and have a Class -I within 6 months of appointment.
Operations personnel are responsible for assessing process performance and making
adjustments to process control systems as necessary for continued treatment, calibrating
control instruments to ensure accuracy, gathering and maintaining information for plant
records and gathering process control samples. Routine maintenance performed by
operations personnel includes cleaning of process components and maintenance of
protective coatings.
At the present time, the number of operations personnel is at an adequate level for the
number of process units and the complexity of the facility. The Wastewater Manager is
required to assess the adequacy of the staffing levels and must determine if additional
staffing is required. Conditions that may require additional staffing include increases in
flow or other loadings, new or additional process units coming on line, additional control
requirements or other situations as encountered. As the recommendations contained in
this report would not add a sufficient number of process units or increase the complexity
of treatment or controls significantly, there is no indication that additional operations
staffing will be required in the immediate future.
The Maintenance staff at the Yakima WWTP is responsible for preventative and
predictive maintenance of all mechanical, electrical and instrumentation equipment to
ensure the reliability of the treatment facility. Additionally, the maintenance staff
responds to unplanned equipment breakdowns. The mechanical, electrical and
instrumentation components of the treatment plant are visited on a scheduled basis for
routine and major maintenance. A maintenance management system is used to track
maintenance work and to schedule preventive and predictive maintenance. The
maintenance management system is administered by the maintenance staff. The
maintenance supervisor inputs data on maintenance tasks as they are initiated or
completed. To mitigate equipment breakdown before it occurs, the maintenance program
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-43
utilizes specific maintenance information, and operating parameters for all equipment to
evaluate operational status and schedule maintenance intervals.
The maintenance staffing level is outlined in Table 6-20.
Table 6-20
Current Maintenance Staffing Levels
Job Title
Number of Full Time
Equivalents
Industrial Maintenance Supervisor
1
Instrument Technician
1
Preventative Maintenance Technician
2
Industrial Maintenance Mechanic
4
Facility Maintenance Specialist
1
As new equipment and additional treatment process systems are added and existing
systems get older, additional Maintenance, electrical and computer staff may be required.
As new equipment is placed in service, the Wastewater Manager should review the
preventative and predictive maintenance program requirements, and add Maintenance
staff as may be needed to maintain the current high level of operation of the Yakima
Regional WWTP. The recommendations contained in this report would not add
sufficient systems or components to warrant an increase in maintenance staffing in the
near future.
6.5.2 Pretreatment Program
As a part of the NPDES Permit effective June 1, 2003, the City of Yakima was to
implement an Industrial Pretreatment Program in accordance with the approved
"Industrial Pretreatment Program" as submitted to the Washington State Department of
Ecology.
The City of Yakima recently adopted a new ordinance to provide the legal authority for
full implementation of the Industrial Pretreatment Program. The adopted ordinance:
• Defines public sewer use requirements.
• Defines pretreatment standards and requirements, including limitations on
wastewater strength, slugloads and accidental discharges.
• Defines reporting and monitoring requirements for industrial dischargers.
• Establishes a discharge review, authorization and permit process for both new and
existing Significant Industrial Users (SIU's) and Minor Industrial Users (MIU's).
• Establishes administrative enforcement authority and procedures.
• Establishes judicial enforcement authority and procedures.
• Defines requirements for septage and liquid hauling.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-44
The ordinance requires all existing Significant Industrial Dischargers to have a current,
valid wastewater permit (issued either by WDOE or the City of Yakima) in effect as of
the date of full delegation; June 15, 2003. SIU's with permits expiring on or after the
date of delegation are required to immediately submit an application to the City in
accordance with the ordinance. In an on-going process, the City will be converting all
existing wastewater permits issued by WDOE to permits issued by the City.
All Minor Industrial Users whether new or existing will be required to obtain an
Authorization to Discharge in accordance with the ordinance. Minor Industrial Users are
defined by the ordinance as:
"A non-domestic discharger that meets one or more of the following criteria:
1. Discharges wastewater which meets, at least, one of the following criteria:
a. Daily average process wastewater flows exceed five thousand
gallons per day, but not more than twenty-five thousand gallons per day
(excluding domestic wastewater and non -contact cooling water); or
b. Is otherwise deemed by the City to be categorized as an MIU."
At present the City lists twenty-seven (27) Significant Industrial Users, of which twenty-
four have permits in place and three are currently in process of obtaining a permit. While
the number fluctuates, there are approximately 530 Minor Industrial Users required to
obtain an Authorization to Discharge. A process is currently underway to notify all
MIU's of the requirement to apply for an Authorization to Discharge.
The City of Yakima is currently establishing a Fats, Oils and Grease (FOG) program.
This program will be designed to provide regular inspection of MIU's required to provide
grease or oil interceptors. Additionally the program will provide an education component
to inform the owners of the interceptors of the high importance of regular cleaning and
maintenance. The program will also focus on educating the residential sector of Yakima.
The Pretreatment staff is required to enforce the applicable portions of the Municipal
Code, inspect Significant Industrial Users annually, perform annual compliance sampling
of Significant Industrial Users, issue wastewater discharge permits and Authorizations to
Discharge, and inspect Minor Industrial Users for compliance with the terms of their
Authorizations to Discharge.
The current staffing level of the Pretreatment Program is outlined in Table 6-21.
Table 6-21
Current Pretreatment Staffing Levels
Job Title
Number of Full Time Equivalents
Environmental Analyst
1
Pretreatment Leader
2
Pretreatment Technician
2
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 6-45
At the present time, the level of staffing of the Pretreatment Program is adequate to
perform inspection and sampling of SIU's and MIU's. Delegation of the Industrial
Pretreatment Program to the City will increase the workload of the Pretreatment staff.
The majority of this increase will come in additional inspections and in the issuance of
wastewater discharge permits and Authorizations to Discharge. The implementation of a
Fats, Oils and Grease program will significantly increase the inspection and public
interface requirements of the field personnel. One or more technicians, dedicated to FOG
inspection and educational efforts, would be required. It would be anticipated that one or
more field personnel, a vehicle and equipment with additional administrative assistance
may be required to effectively manage the additional workload. An increase in facility
space will be required to accommodate the added personnel. . The additional space and
vehicle will need to be in-place prior to adding additional personnel. Other factors that
may require an increase in staff would include additional SIU categorization. In regard to
the Metal Products and Machinery Category, EPA has determined that this categorization
would be implemented on direct dischargers only, thus negating the need to classify the
majority of the targeted industries as SIU's needing permits or subject to Yakima
oversite. The City of Yakima does not have any direct dischargers of this category. In
the immediate future, the Wastewater Manager will evaluate the expected time frame for
issuance of Authorizations to Discharge and implementation of the FOG program to
determine when additional staffing is warranted.
6.5.3 Strong Waste Program
The four -party agreement (City of Yakima, City of Union Gap, Terrace Heights Sewer
District, and Yakima County) defines "normal" domestic wastewater strength as that
wastewater which contains concentrations of BOD and TSS of less than 300 parts per
million (ppm). The Strong Waste Program currently has adopted this threshold
concentration. Wastewater discharges that exceed these criteria are considered Strong
Waste and are subject to a surcharge.
In conjunction with the 1994 Cost -of -Service Report, individual strong waste categories
were established for all businesses which included most concentrations encountered.
Each business was assigned to the appropriate category based upon national data or
results of in -field testing performed by the Yakima Regional WWTP staff. Any
individual customer within any group may request that their wastewater strength (BOD
and/or TSS) be tested and that their surcharge be adjusted accordingly. The results of any
testing, whether higher or lower, are used to calculate a businesses future surcharge. A
sampling and testing fee is assessed for this wastewater strength analysis. Several
businesses have established through the sampling and testing program that the assigned
wastewater strength has been higher than those found in the businesses discharge. The
surcharge rates for these businesses have been adjusted to reflect the actual strength
observed.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-46
6.5.4 Wastewater Laboratory Staffing and Operation
With the exception of total kjeldahl nitrogen analysis, the wastewater laboratory provides
all of the conventional parameter testing required for process control, NPDES permit
compliance, and the Pretreatment/Strong Waste program. Laboratory staff
responsibilities also include compilation of plant process data and laboratory analytical
data, and coordination of sampling and testing for analytical procedures that require the
services of outside laboratories.
The laboratory's existing priority pollutant instrumentation meets permit requirements for
determining metals and volatile organic compound compliance in biosolids, sprayfield
groundwater, and pretreatment samples. However, the current NPDES permit requires
metals detection limits (ppb) and organic pollutant analytical methods (gas
chromatography/mass spectroscopy) for plant effluent samples that preclude in-house
compliance testing with existing instrumentation. Consequently, influent and effluent
samples are sent to contract laboratories for priority pollutant analyses and "clean" metals
analyses.
Determining compliance with any current or future effluent permit metals limits will
require clean sampling and clean testing techniques. At the present required sampling
frequencies, it is most cost-effective to continue the current practice of sending these
samples to an outside laboratory as opposed to re -configuring the plant laboratory for
clean metals testing (probable cost $900,000). Likewise, the required present influent and
effluent organic priority pollutant sampling frequencies do not justify purchase of the
requisite gas chromatograph/mass spectrometer (GC/MS) (probable cost $85,000.).
Acquisition of clean metals testing equipment and/or a GC/MS should be reconsidered if
a future permit substantially increases the testing requirements.
The current laboratory staff positions are outlined in Table 6-22.
Table 6-22
Laboratory Staff Positions
Job Title
Number of Full Time
Equivalents (Filled/Vacant)
Laboratory Coordinator
1/0
Laboratory Chemist
0/1
Laboratory Technician
3/1
The present level of laboratory staffing is adequate to meet the current sample load. If the
scope or frequency of process control, Pretreatment program, or Strong Waste program
sampling increase, one or both of the vacant laboratory positions should be filled.
Process control and permit compliance testing are expected to remain relatively constant
under the current permit. As Pretreatment finalizes parameter lists and sampling
frequency plans, near-term laboratory staffing requirements will come into focus. The
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-47
implementation of the Pretreatment Fats, Oils, and Grease program will certainly increase
laboratory sample load and warrant the hiring of a laboratory technician.
The laboratory has adequate bench space and floor space for increased conventional
testing.
Expanded BOD, FOG, or solids testing could be accommodated quickly by establishing
new workstations on open bench space. If increased BOD sample load were to exceed
incubator room capacity, freestanding incubators are commercially available. Any long
term increase in conventional sample load would warrant filling the vacant laboratory
technician position.
The current permit's stringent metals limits and studies to update the City's local metals
limits may necessitate expanded plant and Pretreatment metals testing. This would
require that the laboratory fills the vacant chemist position and acquires updated
analytical equipment in the form of an ion coupled plasma/optical emission
spectrophotometer (ICP/OES) (probable cost $90,000.). Metals analysis with the
laboratory's current flame and furnace atomic absorption (AA) instrument is labor
intensive. The instrument measures only one metal at a time requires re -configuration for
each metal, provides limited calibration ranges, and requires frequent sample dilutions.
The performance of the existing furnace AA for arsenic and selenium is marginal,
particularly for complex matrices like biosolids. An ICP/OES is capable of determining
more than twenty metals simultaneously, over a wide calibration range, during one
analytical run. An ICP/OES instrument would meet foreseeable biosolids, process, and
Pretreatment metals needs.
A second alternative to the current metals instrumentation is a Zeeman furnace/flame AA
(probable cost $80,000). This instrument, though still labor-intensive relative to an
ICP/OES, provides a wide calibration range and the optics/electronics to compensate for
complex matrix interference. Both factors increase sample throughput substantially.
Laboratory staff is currently developing conventional protocols for selected anion
(sulfide, sulfate, nitrate, o -phosphate) analyses in order to meet process control requests
for in-house testing, particularly during the DelMonte discharge season. It is also
anticipated that the State may establish Yakima River water quality criteria, and thereby
possibly effluent permit limits, for some of these same ions. Additionally, some of these
analytes represent required input parameters for models that may determine future metals
criteria and permit limits. Staff is working with existing spectrophotometers to measure
these parameters. These techniques are adequate for a limited sample load. Increased
demand for ion analysis might justify purchase of an ion chromatograph (probable cost
$35,000), which is capable of determining multiple anions or cations during a single
analytical run. It is recommended with the additional testing and work load that two
additional staff are hired within the next 6 yrs. Future equipment purchases include
IEP/OES and a spectrophotometer.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 6-48
6.6 Maintenance Improvement Projects
Table 6-23 presents a list of recommended maintenance -related improvement projects
which are compiled from the Operations & Maintenance Issues portion of Section 5, but
have not been discussed in Section 6. The opinion of probable cost is included.
Table 6-23
Maintenance -Related Improvement Projects
Facility Description
Opinion of
Probable Cost
Replacement of Primary Clarifier Collector Mechanisms
$2,275,000
Primary Sludge Pumping Density and Flow Meters
$240,000
Primary Digester Building Lighting Replacement
$49,000
Primary Sludge Pumps Replacement
$100,000
Replacement of Secondary Scum Pumps and Piping
$80,000
Raise Intermediate Degritter Center Wall
$250,000
Trickling Filter Door/Walkway Covers
$85,000
Aeration Basin Diffusers Rehab
$50,000
Refurbish Secondary Clarifier Bull -Gears
$130,000
Replace Secondary Clarifier Skimmer Mechanism/Scum Box
$362,000
Refurbish DAFT Air Compressors/Pipelines
$65,000
Structural Repairs to Aeration Basins 1-3
$750,000
Upgrading Two Existing Secondary Clarifier Launders for Algae
Control and Improved Access
$195,000
Secondary Clarifier Spray Nozzle Installation
$15,000
Grease Receiving Facility
$125,000
Weather Protection for Odor Control Towers
$50,000
Total Opinion of Probable Costs
$4,821,000
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 6-49
SECTION 7
ANALYSIS OF POWER DISTRIBUTION & SCADA SYSTEMS
7.1 Introduction
The purpose of this section is to summarize existing Power Distribution components at
the Wastewater Treatment Plant, both on the normal power and standby power systems,
and provide options and cost projections for possible upgrades. Additionally, this section
summarizes existing Supervisory Control and Data Acquisition (SCADA) components at
the Wastewater Treatment Plant and remote lift stations (including hardware, software,
and network related items) in order to identify options with associated costs for future
SCADA upgrades, and to make an initial recommendation.
The summary is based on:
• Review of existing documentation provided by the facility.
• Field investigation of existing conditions.
• Interviews and meetings with treatment plant staff conducted to evaluate desired
operating parameters, and any concerns or limitations with the existing systems.
• Phone conversations with equipment and software vendors.
7.2 Existing Power Distribution System
The existing power system consists of the utility service, normal power supply, and
standby power supply.
7.2.1 Utility Service
The normal power service to the plant is provided from the local electrical utility, Pacific
Power & Light, via a dip from a 12.5 kV overhead distribution utility line located at the
north end of the plant. The service is protected by a pole mounted utility fuse rated for
100 amps which allows a load of about 2200 kVA.
7.2.2 Normal Power
The plant electrical power distribution system consists of a combination of medium
voltage distribution at 12.47 kV, three-phase, with on-site transformation to 480 volts,
three-phase, and 480 volt, tluee-phase distribution feeders for both normal and standby
power. At the normal power on-site point of service, the single utility three-phase line is
divided into two circuits that supply two separate busses in the plant 15 kV switching
equipment. Froin the switches to the loadcenters in the plant there are dual, parallel
sources of normal power supply for the plant process areas served by the three double -
ended load centers at the influent and aeration areas. However, there is not a second
normal power supply present at Substation 4 which serves the following process areas:
Chlorination Building; Dechlorination Building; and the Intermediate Degritter Pump
Station. The normal power distribution system has a capacity of more than 6750kVA or
about 3000kVA with one end of each double -ended transformer/480volt switchgear
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 7-1
loadcenter out of service. Plant load is less than 1500kVA and the projected increase in
load is 400-500kVA for identified improvements.
7.2.3 Standby Power
The standby power service to the plant is provided from a diesel engine -generator located
in the Influent Building at the north end of the plant. The generator is rated
400kW/500kVA or about 600 amperes at 480 volts. In some of the process areas, the
standby power engine generator provides a second source of power. The existing engine
generator set is an ILI unit with a Cummins diesel engine and was installed in 1980. The
unit appears to be in good condition with less than 700 hours of service on the engine and
no apparent signs of damage or overloading.
Standby power is distributed at 480 volts, three phase from the engine -generator via a
standby power distribution switchboard. This switchboard connects directly to portions
of motor control centers in five areas of the plant using transfer switches in the MCC
lineup in parallel with the normal power distribution system that supplies these motor
control centers.
7.2.4 Existing Power Distribution System Assessment
The electrical power distribution system operates with good reliability and appropriate
voltage levels throughout the plant. Some areas of non-selective overcurrent protection
exist in the plant, but do not appear to result in exposure to simultaneous outage of vital
components. Overvoltage protection is limited, but has not resulted in known cases of
failure or component damage. Electrical metering is analog and limited and is not
connected to or supported by the SCADA system, but power distribution system
equipment and circuits are generally lightly loaded and the limited metering is not
considered significant. Harmonic loading cannot be evaluated without testing as the
metering does not measure this characteristic of the power distribution system; some
problems have occurred in the past but were corrected by addition of filters on the large
VFD's, no known harmonic loading or interference problems are currently reported by
plant maintenance staff.
Electrical equipment and materials are generally well maintained and in good condition.
A three-year electrical maintenance program was completed in 1998. The electrical
equipment maintenance program has minimized nuisance electrical problems and
unscheduled outages. Primary switching equipment, primary power feeders, unit
substation transformers, low voltage switchgear, and motor control centers appear to have
a minimum of twenty years of useful life if consistent maintenance is performed over that
period. Some equipment may require increased maintenance or component replacement
during that time period to remain serviceable. Parts remain available for the General
Electric and Westinghouse equipment, but the product lines are out -of -production and
several generations obsolete (Westinghouse is no longer in the electrical equipment
business and the successor companies, primarily Cutler -Hammer, have indicated there
will be limited parts availability in the future for the Westinghouse products).
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 7-2
Replacement of the Westinghouse motor control centers may be needed within the
twenty-year time period, at an approximate cost of $91,000.
The VFDs with associated transformers and filters that operate the four 400 horsepower
blowers are less efficient than newer units, are near the end of their useful life, are old
technology, and have limited spare parts availability. The VFD's and associated
equipment and circuits need to be replaced unless the blowers are to be upgraded with a
different size or type of unit which might preclude the use of a VFD or require a VFD
unit not of this size.
7.3 Power Distribution Capacity and Required
Modifications
The discussion in this section includes the capacity of the existing power distribution
system to accommodate additional load, and possible requirements for modifications to
the existing distribution system based on EPA and WDOE requirements. Specifically,
the discussion includes:
• Capacity ratings of existing distribution components
• EPA Class I & II and WDOE design/reliability requirements
7.3.1 Power Distribution System Capacity
The capacity of the normal and standby power distribution systems is discussed in this
section.
7.3.1.1 Normal Power
Planned improvements to process areas are discussed in Sections 5, 6, and 9. The
additional electrical load associated with these improvements appears to be
approximately 400-500kVA. In general, the normal electrical power distribution system
has adequate capacity for this load growth. There does not appear to be a need for
increased capacity from the electrical utility or at the main service switchgear. However,
in some process areas there is limited capacity at a particular bus when connected load is
at or above rated capacity. While load diversity generally results in the loads not
appearing at the same time, additional loads should not be added to these busses without
provisions for load shedding. In addition, in some areas there is a mismatch between the
capacity of the transformer (750 kVA, 900 amperes at 480 volts with capability for
increased capacity using fan cooling) serving the area and the bus/breaker rating of the
switchgear (1600 amperes) or the distribution equipment and the motor control
equipment (800 amperes). In these cases, when improvements are made that increase
load beyond the capacity of the existing bus but within the capacity of the existing
transformer, upgrades or new equipment inay be required to serve the increased loads.
This condition exists in at least the following two areas:
• Substation 3A
• Substation 3B
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 7-3
It appears that in these cases, the secondary bus capacity can be upgraded to meet the
capacity of the serving transformer as part of the associated planned improvement project
and that no action is required until that time.
7.3.1.2 Standby Power
Typical loading on the existing standby generator during exercise or power failure events
has been reported to be about 200 amperes or about 1/3 of the 500 kVA generator
capacity. The unit was load tested and, with the exception of needing minor maintenance,
performed at rated capacity. Therefore, since the unit appears capable of running at rated
capacity, it appears that an additional 250 to 300 amperes or about 200 to 250 horsepower
of smaller loads could be added to the standby electrical power system without exceeding
80% of the generator rating.
hi general, capacity for added standby power load at each motor control center is limited
and additions will require evaluation on a case-by-case basis. Physical space for
additional units to serve new loads is very limited in many cases and may require sub -
feeding new distribution or motor control equipment for these loads.
7.3.2 EPA Class I & II Reliability and WDOE Requirements
EPA Class I & II reliability requirements for the power distribution system specify "vital"
process equipment that must have redundant power distribution. EPA design criteria
requires that the quantity of process equipment defined as "vital" must exceed the
quantity of that equipment that is necessary to perform the required function by a
minimum of one unit.
7.3.2.1 Normal Power
Two examples of normal power systems that have been evaluated with respect to
reliability requirements are provided in this section.
Substation 4 Example - Substation 4 is currently served by a single normal power
transformer. Furthermore, the transformer is "unit substation style" and, if replacement is
required as a result of a failure, it may take several weeks before it is delivered to the site
once ordered. Since Substation 4 serves process areas that are required for the operation
of the plant, it appears that the EPA reliability requirements may not be met at the present
time.
Trickling Filter Pumping - EPA design criteria requires that the quantity of process
equipment defined as "vital" must exceed the quantity of that equipment that is necessary
to perform the required function by a minimum of one unit. While it appears that the
quantity of trickling filter pumps meets this requirement, all four are electrically
connected to the same power distribution bus, making this bus a single point of failure.
This situation does not meet the EPA design criteria.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 7-4
It is also possible that this condition exists for other process equipment at the plant.
Therefore, "vital" equipment should be defined during preliminary design, and each bus
associated with "vital" equipment should be evaluated to determine if EPA design criteria
are satisfied.
7.3.2.2 Standby Power
Two key systems that were evaluated with respect to standby power requirements were
the aeration blowers and the trickling filter pump station.
Aeration Basin Blower Operation - Providing standby power capacity for aeration blower
operation is required under EPA Class I & II and WDOE requirements in order to keep
the "biota" alive when normal power experiences an extended outage. In addition, odor
from aeration basins, and eventually trickling filters or digesters, could be a concern if an
extended outage occurs. Normal power service generally has been reliable with power
outages limited to a half day or less. However, a system outage of longer duration is
possible (such as occurred on the East Coast in 2003).
The addition of standby power to the aeration blower would require replacement of the
existing engine generator with a larger unit (800-1200kW) or providing a second unit
(600-800kW) at the aeration blower area. Problems associated with replacement of the
existing engine -generator unit are that the new unit would require additional space and
that the existing standby power distribution switchboard would need to be replaced or
subfed by a new, larger board. Sufficient space within the existing generator room may
not be available for the larger equipment. Provision of a second unit at the aeration area
would be less costly initially (if the existing standby power engine -generator unit and
distribution equipment was retained) but would result in additional ongoing costs for
exercising, maintenance and power for the second unit that, combined with the cost of the
present unit, would exceed the operations and maintenance cost for a single, larger
engine -generator unit.
The capacity needed to serve the aeration area will vary depending on the blowers to be
served. The load of new single stage blowers would be less than that of the present
positive displacement blowers. This could permit a reduction in engine generator
capacity of approximately 200kW, making a 600kW unit adequate versus a minimum of
an 800kW unit. This would reduce the cost of standby power for this area by
approximately $90,000.
The required capacity may also increase if UV disinfection is provided at the plant. This
would increase load and required capacity by approximately 300kW and increase the cost
by approximately $170,000. These cost adjustments are reflected in the costs for aeration
blower options and UV disinfection options in Section 6.
Table 7-1 shows the projected cost for adding standby power capability to the aeration
blower operation by providing a separate engine generator and a standby power
distribution switchboard in the aeration blower area.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 7-5
Table 7-1
Aeration Blower Standby Power Addition
Component
Cost
New 800kW/1000kVA Engine Generator
$150,000
Generator Building and Fuel Tank
$55,000
1600A Distribution Switchboard w/2 Feeders
$7,000
800A Transfer Switch (2 @ $12,700 ea)
$25,000
800A Feeder (2 @ 200' x $80/ft)
$32,000
800A Service Entrance w/ Main Breaker (2 @ $9,000 ea)
$18,000
Subtotal
$287,000
30% Contingency
$87,000
Subtotal
$374,000
25% Engineering/Legal/Administration
$95,000
Total
$469,000
Trickling Filter Pump Station - The addition of standby power to the trickling filter pump
station loads appears necessary to maintain treatment quality and to preserve the "biota"
during a normal power failure. The following cost projection assumes that the trickling
filter loads can be served from the existing engine -generator, and includes splitting the
bus in the pump station MCC and two independent feeds to the two buses to meet
EPA/WDOE reliability requirements as discussed above.
Table 7-2
Trickling Filter Standby Power Addition
Component
Cost
Distribution Switchboard w/ Feeder Breaker
$7,000
400A Transfer Switch
$18,000
400A Feeder (400' x $40/ft)
$16,000
MCC Modifications
$24,000
Variable Frequency Drive
$44,000
Subtotal
$109,000
30% Contingency
$33,000
Subtotal
$142,000
25% Engineering/Legal/Administration
$36,000
Total
$178,000
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 7-6
7.4 SCADA Components
The existing wastewater treatment SCADA system components discussed in this section
is depicted schematically on Figure 7-1 and consists of the following components:
• Electronic Controllers
• Human Machine Interface (HMI) software
• Computer Hardware & Software
• Network Communications
7.4.1 Electronic Controllers
The existing controllers at the wastewater treatment plant and at each of the remote lift
stations are manufactured by TESCO, and include LIQ 4, LIQ5, and L2000 models,
although a SLC 5/03 is used for an OEM application. The LIQ 4 model is no longer
manufactured, but is still supported by TESCO. Table 6-1 indicates the model, location,
and network address of each of the existing TESCO PLCs. This information was taken
from existing schematic drawings and has not been fully verified with field investigation
Several of the TESCO controllers are located within the treatment plant in such a manner
that, should replacement be required or desired at some point in the future, one-for-one
replacement may not be necessary. Table 7-3 depicts where it may be desirable to
combine wiring for Inputs/Outputs to a single PLC versus replacing each TESCO with an
individual PLC. Additionally, it may be desirable to eliminate the Admin Building
TESCO unit, which is not used except for local annunciation. This function can be
performed by the HMI computer. With this approach, it appears that approximately 11
controllers could be eliminated without sacrificing capability. This is discussed further
below.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 7-7
Table 7-3
Summary of TESCO PLCst
Location
Model
Address
Network
Proposed
PLC
Address
Activated Sludge Pump Station Building
Liq 4
13
Seg. 2
1
Activated Sludge Pump Station Building
Liq 4
14
Seg. 2
1
Administration Building (Main Control Panel)
Liq 4
16
Seg. 1
None
Blower Control Building (Blower Control RTU
Panel Section "B")
Liq 4
8
Seg. 2
2
Blower Control Building (Blower Control RTU
Panel Section "A")
Liq 4
7
Seg. 2
2
Boiler Building
Liq 4
6
Seg. 1
3
Chlorination Building
Liq 4
15
Seg. 1
4
Chlorination Building
Liq 4
20
Seg. 1
4
Dechlorination Building
Liq 4
21
Seg. 1
5
Dechlorination Building
Liq 4
22
Seg. 1
5
Dechlorination Building
Liq 4
23
Seg. 1
5
Digester Building
Liq 4
9
Seg. 2
6
Digester Building (Primary Digester Control Panel)
Liq 5/30
26
Seg. 2
6
Secondary Digesters (Digester Gas Control Panel)
Liq 5/30
25
Seg. 1
6
Industrial Waste Pump Station Building
Liq 4
3
Seg. 1
7
Industrial Waste Pump Station Building
L2000
2
Seg. 1
7
Sludge Transfer Building
Liq 4
4
Seg. 1
8
Solids Handling Building
Liq 4
19
Seg. 2
9
Solids Handling Building
Liq 5/30
10
Seg. 2
9
Influent Building
Liq 5/30
1
Seg. 1
10
Trickling Filter Pump Station Building
Liq 5/30
18
Seg. 1
1 I
Trickling Filter Pump Station Building
L2000
17
Seg. 1
1 1
Lakeside Street L.S.
Liq 4
?
Wireless
12
Race Street Lift Station
Liq 4
52
Wireless
13
Rudkin Road Pump Station
Liq 4
24
Wireless
14
Sierra View Estates
Liq 4
53
Wireless
15
Stonehedge Development
Liq 4
55
Wireless
16
Tamarak Lift Station
Liq 4
51
Wireless
17
Valley Mall Blvd Flow Monitoring Station
L2000
?
Wireless
18
Yakima Armory and Readiness Center Sewage Flow
Monitoring
L2000
60
Wireless
i9
Names of existing PLC locations were taken from existing documentation and may differ from names used by
plant personnel.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 7-8
7.4.2 Human Machine Interface Software
The Human Machine Interface (HMD software currently in use at the WWTP is
FactoryLink 6.6 and is sold by Tecnomatix. A runtime version of FactoryLink 6.6 resides
on the SCADA #1 Server and a development version of FactoryLink 6.6 resides on the
SCADA #2 Server computer. The runtime version acts as the primary HMI server
whereas the development version is configured to be a hot standby for the runtime
version. As of January 2004, FactoryLink 7.2 was the most recent version of FactoryLink
available from Tecnomax.
The alarm subsystem is supplemented by utilizing SCADAIarm 4.2 software to
annunciate alarms over a local public address system. (Because the facility is manned
continuously, the alarm dialer capability of SCADAIarm is not utilized.) Since the two
SCADA servers act as a hot standby system, SCADAIarm is installed on both computers.
Remote access is either by FactoryLink "Webclient" access software or by the Symantec
PCAnywhere remote access software. Remote access is from a computer in the
Administration Building, a computer in the Solids Handling Building, or a computer in
the Maintenance Building.
7.4.3 Computer Hardware & Software
SCADA Server #1 and SCADA Server #2 are Dell Precision 410s with 450 MHz Intel
Pentium II processors, 256 MB of DRAM, 9 GB SCSI hard drives, Digi AccelePort X4
ISA EIA -232 serial port UO adapters, and other components typical of this computer
class. These computers both have Windows NT Server 4.0 operating systems and run
SQL Server 7.0, which is used to log historical alarms from the local computer. As noted
above, both computers run FactoryLink 6.6, SCADAIarm, and PCAnywhere.
The Historical Database Server is also a Dell Precision 410 with 450 MHz Intel Pentium
II processors, 256 MB of DRAM, two 9 GB SCSI hard drives, an internal Iomega Jazz
drive, an external tape drive, and other components typical of this computer class. It runs
Windows NT 4.0 Server and SQL Server 7.0 and is used as the historical data repository.
All of these computers are currently located in the Sludge Transfer Building.
7.4.4 Network Communications
Currently, the existing plant PLCs are connected in two network segments that
communicate via RS -485 over shielded twisted pair cable. Each server connects to each
of the three RS -232 three -port bridge devices designated as a "NPMSs" in the plant
documentation. (When a server is in the standby mode it will only listen to serial traffic.
Consequently, data sent to the bridge will either be from the S CADA network or from the
computer which is not in standby.) One of these bridges is connected to the modem
servicing wireless connections to remote PLCs. Another one connects to a RS -232 to
RS -485 converter (also known as a line driver) and then to PLC network segment #1.
The other bridge connects to a RS -232 to RS -485 converter and then through a pair of a
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 7-9
RS -485 to fiber optic cable converters and finally on to PLC network segment #2. The
fiber optic segment runs between the Sludge Transfer Building and the Solids Handling
Building. Note that a fiber optic segment between these two locations is part of network
segment #1, but the RS -485 to fiber optic cable converter is unconnected in the Solids
Handling Building. A redundant pathway connecting network segment #1 to network
segment #2 exists between and the Tickling Filter Pump Station and the Solids Handling
Building.
The three RS 232 serial connections from each computer to the bridges noted above are
sourced from the Digi AccelePort X4 adapter cards.
The three SCADA computer servers are networked via a 10 Base T hub and UTP
patchcords. This hub is connected to a 10 Base 2 (Thinnet) network via a 10 Base T to 10
Base 2 bridge. This 10 Base 2 network runs to the Administration Building where it
connects to a SCADA client computer and a 10 Base FL (fiber) hub with a 10 Base 2
port. The 10 Base FL ports connect via fiber optic cable to the Maintenance Building and
to the Solids Handling Building. Each of these locations has a 10 Base FL to 10 Base 2
bridge. The Solids Handling Building also has a 10 Base T hub with a 10 Base 2 port
with a single computer connected via an UTP patchcords.
7.5 SCADA Issues
The following issues have been identified by facility personnel, or were identified during
the course of reviewing existing documentation and onsite conditions. These issues were
considered in developing the SCADA options discussed below, and are addressed as part
of the SCADA recommendations section that follows.
7.5.1 Technical Support
Operators have identified concerns over the technical support provided for the TESCO
equipment. The limited number of support personnel combined with the fact that they
must be dispatched from a California office, has resulted in long response times and a
perceived high cost. TESCO is also a small PLC manufacturer with a limited market
share as compared to major manufacturers such as Allen Bradley and Square D. As a
result, long term company viability and market share are a consideration for the future of
the SCADA system.
7.5.2 System Reaction Time
Operators have commented that setpoint changes made in the FactoryLink HMI take up to
2 minutes to update on the HMI screen. It appears that this is a result of latency (or delay
time) associated with the number of RS -485 connections, the network topology and
protocol, and the amount of information being transmitted between the individual PLCs
and the HMI servers. An operator mentioned that previous systems implemented
dynamic reordering of poll sites in order to minimize perceived latency when changing
setpoints whereas the present system maintains a static order of the poll sites.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 7-10
7.5.3 Report Generation
Operators have commented that it is difficult to develop new reports using the historical
data stored in the SQL Server database. Currently, outside consultants are hired when
reports are required that have not previously been created and saved as a template. This
increases operational costs.
7.6 SCADA Options and Projected Costs
Three options have been considered for the existing SCADA system based on the issues
discussed above:
• Option 1— Maintain and expand existing SCADA system with like components.
• Option 2 — Replace major SCADA components as part of a single project.
• Option 3 — Incremental major SCADA system component replacement.
7.6.1 Option 1 — Maintain and Expand Existing System
The existing SCADA system is functional, and the operators are familiar with the system.
It is possible that costs associated with SCADA system upgrades could be deferred in
total until such time that there is funding available, or one of the following conditions
occurs:
• Failure of one or more existing TESCO controller. If this should occur, the unit
could be replaced by another TESCO controller.
• Inability of an out -of -production TESCO unit to meet needed I/O expansion for
process improvements. If this should occur, the unit could be replaced by another
TESCO controller.
• New process units are placed into service that require new PLCs. If this should
occur, a new TESCO controller could be added.
• TESCO discontinues selling/supporting their electronic controller line. If this
should occur, some action will be required to maintain SCADA system
operations.
Any of the above situations could also initiate consideration of Option 2 or 3 below.
7.6.2 Option 2 — Major SCADA Component Replacement
This option involves replacing the major SCADA system components (at the WWTP and
the remote lift stations) as part of a single project. Replacement would include PLCs,
Computer hardware and software, HMI software, and historical data logging software.
This wholesale replacement would also require installation of new fiber optic backbone
communications and associated peripherals between several buildings on site. Table 7-4
shows the projected costs associated with a Major SCADA Component replacement.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 7-11
Table 7-4
Major SCADA Component Replacement Cost Projection
Component
Cost
WWTP Equipment
$116,000
WWTP Contractor Services
$89,000
Fiber Backbone (Pathway, Cable, Equipment)
$79,000
Remote Site Equipment
$44,000
Remote Site Contractor Services
$26,000
Computer Hardware/Software
$26,000
Subtotal
$380,000
30% Contingency
$114,000
Subtotal
$494,000
25% Engineering/Legal/Admin
$124,000
Subtotal
$618,000
PLC/HMI Programming & Startup'
$240,000
30% Contingency
$72,000
Total
$930,000
1 PLC/HM[ Programming and startup could be performed as a Contractor or Engineering Service.
This option would address all of the issues presented above, and is the desired option by
the City at this time.
7.6.3 Option 3a — Incremental Major SCADA Component Replacement
This option involves creating a 2nd PLC communications netvork using Ethernet over
fiber optic cabling, and connecting it to the existing HMI computer network, as well as
replacing remote site TESCO equipment and upgrading computer hardware and software.
As new PLCs are added (for new process equipment), or existing TESCO controllers
require replacement, new PLCs from one of the major manufacturers (such as Allen
Bradley or Square D) would be purchased and placed into service on the new
communications network. PLC replacement would continue incrementally as funding
allowed, until all TESCO controllers were replaced and only the Ethernet
communications network was required.
The new fiber optic backbone infrastructure would be required when the first new PLC
was placed into service. It may be possible to incrementally add fiber backbone
infrastructure to areas affected by PLC addition/replacement, but this would be
determined by the fiber backbone topology selected at the beginning of the replacement.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 7-12
1
This option does not necessarily require replacement of any SCADA Server computers,
operating systems, HMI software, or SQL Server database software. However, these
hardware and software systems are inter -related, and if the City selects to upgrade to new
hardware or to new software versions, it may trigger replacement of other hardware or
software components. Therefore, these costs are included in the projection below.
The performance and support issues discussed above would be addressed over time under
this option, with system performance and support both improving as more locations are
placed into service on the new PLC network.
The following cost projection depicts the new fiber optic backbone infrastructure only.
Each PLC location placed onto this new PLC network would add approximately $13,000
- $15,000 of equipment and Contractor costs plus associated contingency and engineering
related costs. There may be economies of scale if several locations are designed,
constructed, and placed into service concurrently.
Table 7-5
Incremental SCADA Component Replacement Cost Projection
Component
Cost
WWTP Equipment
$33,000
WWTP Services
$46,000
Remote Site Equipment
$44,000
Remote Site Services
$26,000
Computer Hardware/Software
$26,000
Subtotal
$175,000
30% Contingency
$53,000
Subtotal
$228,000
25% Engineering/Legal/Administration
$57,000
Total
$285,000
7.6.4 Option 3b — Incremental Major SCADA Component Replacement
Similar to Option 3a, this option involves creating a 2"d PLC communications network
using Ethernet over fiber optic cabling, and connecting it to the existing HMI computer
network. As new PLCs are added (for new process equipment), or existing TESCO
controllers require replacement, new PLCs from one of the major manufacturers (such as
Allen Bradley or Modicon) would be purchased and placed into service on the new
communications network.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 7-13
However, it is also possible to convert the existing TESCO controllers to communicate
via the new Ethernet fiber optic backbone until such time that they are replaced. This
would increase the initial cost, but would also improve system latency immediately, as
opposed to the incremental improvement found with Option 3a.
To connect the existing TESCO controllers to the new Ethernet fiber optic backbone, an
RS -485 to fiber converter would be placed at each concentration point of the TESCO RS -
485 network. The number of TESCO controllers on each network segment would likely
be reduced, and the number of network segments increased. This would likely require
some new pathway and RS -485 cabling. However, the smaller number of network
segments, combined with the speed of Ethernet communication should decrease system
latency, and position the WWTP for future PLC replacement. This option also does not
necessarily require replacement of existing computer hardware or software.
The increased cost from Option 3a is projected to be $185,000. An additional 30%
contingency of $56,000 and an additional 25% for engineering/legal/administration of
$60,000 bring the Option 3b projected cost to $586,000.
7.7 SCADA Recommendations
Based on discussions with City personnel and operations staff, Option 2, Major SCADA
Component Replacement, is the recommended approach for the SCADA system. While
the initial capital cost is higher, the expected life cycle of the new SCADA system is
much greater, and there is no requirement to operate two systems simultaneously, as
would be the case with an incremental approach.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 7-14
SLUDGE TRANSFER
BUtDING
SCADA
SERVER
140. 1
VOICE DIALER 4
SERIAL
(RS -232)
„PUBLIC
ADDRESS
SYSTEM
RADIO
MODEM
•
RF
%CE WR
10/100 NIC
SERIAL
MODE
SERIAL
BRIDGE
10 BASE T
HQB
SERIAL
BRIDGE
4
SCADA
SERVER
NO. 2
WILE INALER
SERIAL
(RS -232)
10/100 NIC
REMOTE
(TYPICAL)SI
TYPICAL) TE
TESCO
L2000
SERIAL
(RS -232)
MOTE SITE
TYPICAL)
TESCO
LIQ IV
RADIO
M00€4
RF
XCE VER
•
WTTP PROCESS AREA SITE
(TYPICAL)
WITP PROCESS AREA SITE
(TYPICAL)
SOLIDS HANOJNG
WILDING
F18ER
RS -485
•
V
10 BASE 2
10 BASE FL
•
10 BASE 2
10 BASE FL
FIGURE 7-1
e
BLACK & VEATCH
Black & Veatch Corporation
Seattle, Washington
Conley Engineering, Inc.
Consulting Electrical Engineers
205 North 40th Ave. Suite 201
Yakima, Washington 98908
TEL: (509) 965-9872
FAX: (509) 965-9873
CITY OF YAKIMA
YAKIMA REGIONAL WASTEWATER TREATMENT PLANT
SCADA SYSTEM BLOCK DIAGRAM
SECTION 8
GAS UTILIZATION AND COGENERATION
8.1 Introduction
The purpose of this section is to evaluate options for the use of methane gas produced in
the anaerobic digesters and make recommendations for future utilization of the gas.
Issues discussed in this section include the following:
• Anaerobic digester gas production
• Digester and building heating requirements
• Digester gas utilization
• Digester gas system improvements
• Heating system modifications
8.2 Digester Gas Production
Table 8-1 below summarizes the initial and design year average daily gas production
from the anaerobic digester system.
Digester gas production is based on projections of increased wastewater loading to the
plant. These projections are contained in Section 4 and are based on projected primary
and secondary sludge loading to the anaerobic digesters.
Table 8-1
Digester Gas Production Annual Average
Year
Projected Digester Gas
Production (ft3/day)
Projected Net Heat Available
from Digester Gas, mBtuh'
Initial Year, 2004
125,700
2,510
Design Year, 2024
179,200
3,580
'Based on digester heating value of 600 Btu/ft3. Net heat is the amount of heat that
can be produced from a boiler. Boiler efficiency was assumed to be 80 percent.
8.3 Digester and Building Heating Requirements
Design digester heating requirements was determined based on sludge projections
contained in Section 4 and operating the digesters at mesophilic conditions at 95 F. The
initial year, 2004, digester heating requirement will be about 2,200 thousand British
thermal units per hour (mBtuh) and for the design year, 2024, the digester heating
requirements will be about 3,200 mBtuh. If thermophilic digestion is considered at 135
F, the digester heating requirement will increase for the initial year to about 3,800 mBtuh
and for the design year to about 5,600 mBtuh.
Table 8-2 below summarizes design building heating requirements for the waste
treatment plant. Future building heating requirements consider the expansion of the
administration building, a new DAF building, enclosed trailer storage, a new standby
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 8-1
power building, a new RAS/WAS pump station, and a new dewatering polymer system.
The building heating requirements listed are conservative, and further analysis will be
necessary to refine these values, and correlate with field experience.
Table 8-2
Building Heating Requirements
Building
Building Heating
Requirements, mBtuhl
Administration
725
Influent Building
305
Sludge Transfer Building
150
TFPS Building
51
CL2 Building
236
Dechlor. Building
69
Solids Handling Building
479
Digester Building
175
Garage/Shop
340
Garage/offices
200
Headworks Building
475
Storage Building
579
Existing Total
3,784
Administration (2000 square ft)
137
New DAF Building (1900 square ft)
200
Enclosed Trailer Storage
(4000 square ft)
421
New Standby Power Building
(2000 square ft)
211
New RAS/WAS Pump Station
(900 square ft)
95
New Dewatering Polymer System
(900 square ft)
95
Future Total
4,943
'Based on connected load with outside temperature of 5 Deg F and minimum
inside temperature of 70 Deg F.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 8-2
The total heating requirements for digester and building heating is given in Table 8-3.
Table 8-3
Heating Requirements
Year
Digester
Heating, mBtuh
Building
Heating, mBtuh
Total Heating,
mBtuh
Mesophilic Digestion
Initial Year
2,200
3,784
5,984
Design Year
3,200
4,943
8,143
Thermophilic Digestion
Initial Year
3,800
3,784
7,584
Design Year
5,600
4,943
10,543
8.4 Digester Gas Utilization
There are several ways that digester gas can be utilized at waste water treatment facilities.
These are:
• Boilers for digester and building heating.
• Engine driven equipment like blowers or pumps.
• Engine generators to produce electricity.
• Clean the gas to natural gas quality and sell.
Currently the Yakima Regional WWTP is utilizing the digester gas in boilers for heating.
The next most common way to utilize the digester gas is in an engine generator to
produce electricity and recover heat to use for heating the digesters and buildings. This is
defined as cogeneration and this option was further evaluated.
8.4.1 Current Gas Utilization
Currently the primary use of digester gas is in the boilers to provide heating for the
digesters and buildings. Two existing boilers utilize the digester gas, with surplus gas
flared. Each boiler has a heat input of 5,230 mBtuh and based on a boiler efficiency of
80 percent, each boiler has a heat output of 4,184 mBtuh. Based on being fueled with
digester gas having a heating value of 600 Btu/cubic foot, the digester gas consumption
of each boiler is about 209,000 cubic feet per day.
When the digesters do not produce enough gas to meet the digester and building heating
requirements for the plant, the staff will manually switch the boiler fuel to fuel oil.
8.4.2 Cogeneration
Cogeneration is a typical way to utilize the digester gas at wastewater facilities. The gas
can be used as fuel in an engine and the power produced can be used to operate a
generator. The electricity produced can be utilized in the facility to reduce the overall
electricity requirement from the electrical utility. A heat recovery system can be installed
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 8-3
on the engine that will recover heat from the engine jacket water and exhaust. This heat
can be transferred into the existing heating water system and utilized for digester and
building heating.
The opinion of probable cost associated with the installation of a digester gas fueled
engine generator set with either natural gas or propane for fuel backup, and a heat
recovery system is shown in Table 8-4. The associated economic analysis is presented in
Table 8-5.
Table 8-4
Cogeneration Opinion of Probable Cost
Unit
Opinion of
Probable Cost
Engine Generator/Structure
$500,000
Electrical (30%)
$150,000
UC (10%)
$50,000
Site Work and Yard Piping (20%)
$100,000
Subtotal Costs
$800,000
Contingency (30%)
$240,000
Subtotal
$1,040,000
Engineering, legal and administration (25%)
$260,000
Total Opinion of Probable Cost
$1,300,000
Table 8-5
Cogeneration Analysis
Year
Electricity
Generated
Cost of
Electricity
Electricity
Savings'
Maintenance
Cost2
Total
Value
Simple
Payback
kWh
$/kWh
$/Year
$/Year
$/Year
Years
2004
276
0.037
80,600
32,700
48,000
27
2024
394
0.037
114,900
46,600
66,300
20
Generator Capital Cost
$1,300,000
'Based on 90 percent engine generator availability.
2Based on operation and maintenance costs of 1.5 cents per kWh generated.
Based on simple payback as indicated in Table 8-5, the generator installation will not be
cost-effective. Heat recovered from an engine is less than what can be produced in a
boiler. Typically heat recovery from an engine is about 50 percent of the fuel input, for a
boiler this is 75 percent of the fuel input. Because of this, payback will actually be of
greater duration since the value of supplemental fuel required to make up the difference
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 8-4
between the amount of heat from a boiler for the same amount of digester gas was not
included in the evaluation.
If the price of electricity goes up to $0.075/kWh, the simple payback will go down to 10
years for year 2004 costs and 7 years for the year 2024 costs.
8.5 Digester Gas System Improvements
Digester gas is collected from each digester and piped to the boilers for utilization or to
the flare where surplus gas is burned. The gas piping, flare, and other gas equipment are
over 20 years old and may be close to its useful life. Over the years, accumulation of
material in the piping can increase pressure loss in the piping system, thus decreasing the
gas pressure at the boilers. Also, the gas piping will need to be sized to handle the future
design year, 2024, gas flow rates. New digester gas piping should be constructed of 316L
stainless steel with welded fittings. It is recommended the digester gas collection piping
be replaced and increased in size to handle the future gas production.
NFPA 820, Standards for Fire Protection at Wastewater Treatment and Collection
Facilities, provide guidelines for digester gas piping inside facilities. A preliminary
review of NFPA 820 indicates that since most of the gas handling equipment is housed in
the compressor room on the second floor and the room has only exterior exits, the rest of
the building does not need to be classified.
Another gas piping issue is the location of the flare back pressure regulating valve and
flame trap. These items are located in the compressor room, which is about 75 feet away
from the flare. Flame traps are designed to be located within 15 feet of the source of
ignition. Also, it is good practice to locate the back pressure regulator near the flare.
With the back pressure regulator located so far from the flare, there is a chance that air
will get in the piping between the regulator and flare when the flare is not operating.
Then when it does not start, there will be a combination of gas and air in the piping that
could cause a flashback and explosion in the piping. It is recommended the back pressure
valve and flame trap be relocated near the flare.
Digester gas flow meters used at the plant are the inline, turbine type. The plant
personnel have indicated that these meters have not been reliable for the past few years.
For digester gas service, this type of gas meter has moving parts that are in the gas
stream. With the dirty digester gas, they require lots of maintenance. It is recommended
different types of flow meters be investigated when the digester gas piping is replaced.
Moisture from the digester gas can condense out in the piping. With outdoor piping the
condensate can freeze and cause problems. One area this can occur and can cause major
problems is at the piping and flare arrester for the digester cover relief valves. Piping and
valves in areas where problems from freezing can occur should be heat traced. Cost for
heat tracing and installing will be about $1,350 per 100 foot of heat tracing.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 8-5
The opinion of probable costs to replace all the gas piping, valves, and flow meters would
be $236,000. The opinion of probable costs to replace the waste gas flare would be
$68,000.
8.6 Boiler Improvements
8.6.1 Boilers
The existing boilers are fire -tube type and are manufactured by Cleaver -Brooks. Plant
personnel and the boiler representative feel the existing boilers are in good condition and
are anticipated to remain in service for many years. When improvements are made to the
digester facility, the boiler condition should be re-evaluated and replaced if necessary.
For these boilers, boiler efficiency is typically 80 percent of the heat input. The heat
output of the existing boilers is 4,180 mBtuh or a total of 8,370 mBtuh for both boilers.
This total is more than the anticipated heating requirements for mesophilic operation
through the design year, 2024, of 8,143 mBtuh. Therefore the existing boilers, without
redundancy, will have adequate capacity to provide the necessary heating to meet the
total heating requirements. If the plant should decide to switch the anaerobic digesters to
thermophilic operation in the future, the total heating load required for the design year,
2024, will be approximately 10,543 mBtuh, which will be greater than the capacity of the
boilers. Therefore, in the future, the heating loads will exceed the capacity of the existing
boilers and a third boiler should be considered.
When additional heating demands warrant as correlated with field experience, a new
boiler should be installed. The new boiler would match the capacity of the two existing
boilers and would be installed in the same building. The total output of the three boilers
would be 12,550 mBtuh. This total capacity would satisfy the future heating
requirements if the digesters are operated at thermophilic temperatures. If the digesters
are operated at thermophilic temperatures, it is recommended a third boiler be installed in
the existing boiler building. The opinion of probable cost for a new boiler would be
$245,000 including piping, valves, flue, and installation.
8.6.2 Boiler Backup Fuel
Table 8-1, indicates the heat available from the digester gas would initially be 2,510
mBtuh and at design 3,580 mBtuh. Table 8-3, indicates the design heat required for
mesophilic digestion and building heating would initially be 5,984 mBtuh and at design
8,143 mBtuh. This means, especially in the winter months, that a backup fuel is required
to meet the heating requirements. Currently the backup fuel used for the boilers is fuel
oil. Alternative types of backup fuel would be natural gas or propane.
One alternative source of boiler backup fuel is propane. To operate the boiler on
propane, the fuel trains on the boilers will need to be replaced. Also, a propane tank,
vaporizer, and new piping and valves would be required to the boilers. The current cost
of propane is $0.819 per gallon or $0.89 per therm (100,000 Btu). The cost of fitel oil is
currently $1.019 per gal or $0.75 per thenn. Since the cost of fuel oil is less per therm
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 8-6
than propane and there will be addition costs to convert the boilers to propane, it is
recommended propane not be utilized as backup fuel.
Another alternative source of boiler backup fuel is natural gas. Currently, natural gas is
not available on the site. A new natural gas line would have to be installed to the site by
either the local gas utility or by a contractor. Also, the fuel trains on the boilers will need
to be replaced, so they can operate on natural gas. It is recommended in the future when
other digester facility modifications are being made, that installation of a natural gas line
on the site be considered and the boilers backup fuel be changed from fuel oil to natural
gas.
8.6.3 Automatic Fuel Switchover
With the existing boilers, when there is not enough digester gas available to meet the
heating loads, operators have to go to the boilers and manually switch the fuel supply to
fuel oil. Manual switchover of fuels can cause digester gas to be wasted and the full
benefit of the gas not realized. In the future, when digester improvements are made,
consideration to converting the boiler fuel systems to automatic switchover should be
made.
There are times when the boilers have been switched to the backup fuel and digester gas
is being flared because the boilers haven't been switched to digester gas. One way to
save the surplus gas is to compress the gas and store it in a storage tank. The opinion of
probable cost for a new compressor and 2,000 gallon storage tank would be $93,000
including compressor, tank, piping, valves, electrical, I&C, and installation.
8.7 Recommendations
The following is a summary of recommendations:
• Cogeneration as an option for digester gas utilization is not cost effective. It is
recommended to continue utilizing the digester gas in boilers for heating the
digesters and buildings
• The digester gas collection piping is over 20 years old and will need to be upsized
for the design gas production. It is recommended the piping be replaced with
stainless steel piping. The waste gas flare backpressure valve and flame trap
should be located near the flare.
• The existing boilers appear to be in good condition, but the boiler condition
should be evaluated in the future. A new boiler is not required for mesophilic
digester operation. When additional heating demands warrant, a new boiler
should be installed.
• Fuel oil should be continued to be used as the backup fuel for the existing boilers.
Installation of natural gas piping on the site should be considered in the future.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 8-7
SECTION 9
BIOSOLIDS MANAGEMENT
9.1 Introduction
This section summarizes the Yakima Regional WWTP biosolids management program
and provides recommendations for continued beneficial use of the City's treated
biosolids.
9.2 Federal and State Regulations
The USEPA 40 CFR Part 503 regulations establish metals limits, agronomic (nitrogen)
loading requirements, stabilization requirements, and site management requirements. These
rules were finalized in February 1993, and clarifying revisions were proposed in October
1995. Under the final rule published in the Federal Register in August 1999, chromium
limits were deleted and selenium limits were increased.
The Washington State Law regulates biosolids in the Revised Code of Washington
(RCW), Chapters 70.95, 70.95J, and 90.48. This law regulates the biosolids as a
beneficial use and prohibits disposal in a landfill except for emergencies or as a beneficial
use as an intermediate or final cover.
The Washington Department of Ecology (WDOE) defines biosolids through the
Washington Administrative Code (WAC) 173-308 and the Criteria for Sewage Works
Design (the Orange Book). WAC 173-308 is primarily based upon 40 CFR 503.
9.3 Biosolids Quantity and Quality
A mass balance model was used to project solids quantities for the liquid stream processes.
A detailed discussion of this procedure was previously provided in Section 5.3. Projected
quantities were compared to plant data to verify the model. The 2002 -2003 average annual
combined solids production was reported to be 18,200 ppd. In comparison, the mass
balance model projected an average amnual quantity of 20,100 ppd, which is approximately
10% higher than the recorded value. Max month projections did not correspond as closely
due to modeling assumptions regarding the Del Monte loads. Based on the results of the
comparison, the mass balance model was used to project the future quantities that were used
as the basis for the evaluations presented in this section. These quantity projections are
presented in detail in Table 5-2 and are summarized below in Table 9-1.
Table 9-1
Pi ojected Raw Sludge Quantities
Year
Annual Average
(ppd)
Max Month
(PPO
Raw'
Digested
Raw'
Digested
2004
20,900
12,500
31,100
18,600
2014
24,800
14,900
36,800
22,100
2024
30,000
17,900
44,000
26,200
'Includes raw primary, trickling filter and waste activated solids.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05
Page 9-1
Historical data indicated that the existing anaerobic digestion process is achieving
approximately a 50% reduction in total solids. This is a relatively high value compared
to other digestion facilities across the country. A more conservative reduction of 40%
was used for the evaluation of alternatives, to account for any potential changes in
influent characteristics or liquid treatment processes.
The biosolids produced by the current solids treatment process are managed as a Class B
product (as defined by 40 CFR Part 503). The 40 CFR Part 503 pathogen reduction
requirements are met by anaerobically digesting the biosolids for a minimum of 15 days at a
temperature greater than 35 C. The solids treatment process complies with the vector
attraction reduction requirements by meeting or exceeding a 38 percent volatile solids
reduction during digestion. Plant data indicate that the digesters are typically achieving a 60
percent volatile solids reduction.
In accordance with the Part 503 program, the residuals are analyzed for key constituents.
The results of the analyses for 1998 through 2002 have been averaged and are presented in
Table 9-2. As shown in the table, the metals concentrations are significantly lower than the
limits established in 40 CFR Part 503 and WAC 173-308. Based on these data, the City's
biosolids are well below even the lower -tier Pollutant Concentration Limit criteria and,
therefore, do not require tracking of cumulative pollutant loadings at the land application
site.
Table 9-2
40 CFR Part 503 Metal Concentrations'
Pollutant
Average
(mg/kg)
1998 - 2002
Maximum
Ong/kg)
1998-2002
Pollutant
Concentration
Limit (mg/kg)
Ceiling
Concentration
(mg/kg)
Arsenic
18
35.6
41
75
Cadmium
1.6
4.7
39
85
Copper
349
471
1,500
4,300
Lead
46
89
300
840
Mercury
ND2
ND
17
57
Molybdenum
5.0
13.2
No Limit
75
Nickel
13.2
23.5
420
420
Selenium
7.5
14.6
100
100
Zinc
661
1,190
2,800
7,500
' WAC 173-308 values are identical to 40 CFR Part 503 values
2 Non detect or less than minimum detection level
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 9-2
9.4 Biosolids Final Use
The Yakima Regional WWTP biosolids are currently land applied at the Natural
Selection Farms Beneficial Use Facility(N" SF�B j.F), a private land application operation
in Yakima County. NSFBUF has approximately 116,000 acres permitted for biosolids
application. NSFBUF can accept biosolids 7 days per week, from 6 a.m. until 9 p.m.
The site east of Moxee, which was previously used for land application, is no longer
available because much of the acreage was taken out of hops production as a result of the
declining hops market. The city hauls the dewatered cake to the Natural Selection Farms
site, using City -owned equipment.
9.5 Biosolids Processing
The Yakima Regional WWTP solids treatment process consists of.thickeni,'ngzanaerobic
digestion, and dewatering. A schematic of the process is shown in Figure 9-1. A
description of the individual treatment processes and capacities is presented in Section
5.5. Primary solids removed from the primary clarifiers are pumped directly to the
anaerobic digesters. Waste activated sludge (WAS) removed from the activated sludge
process is pumped to the dissolved air flotation thickener (DAFT) for thickening prior to
digestion. Trickling filter (TF) solids removed from the intermediate clarifier can be
pumped to the headworks to eventually settle out in the primary clarifiers, or to the
DAFT for thickening with the WAS. The plant has operated with various TF solids flow
splits, ranging from 100 percent of the TF solids fed to primary clarifiers to a 50/50 split
between the primary clarifiers and the DAFT. It should be noted that the existing_ piping
does not allow TF solids to be sent to the headworks and the DAFT at the same time.
Digested biosolids overflow the primary digesters to the secondary digesters. Digested
biosolids are pumped from the secondary digesters to the centrifuge for dewatering. Dry
polymer is added upstream of the centrifuge. Polymer usage ranges from 23 to 32
pounds per dry ton (lb/dt) of solids, with an average dosage of 28 lb/dt. Centrifuge
centrale is discharged to the south lagoon prior to return to the headworks.
A horizontal screw conveyor transports the dewatered cake to an inclined screw
conveyor, which transfers the cake to a hopper at the north end of the Solids Handling
Building. The hopper provides approximately 20 minutes of storage. Solids are
transferred from the hopper to the truck using a second inclined screw conveyor. Truck
load out is performed in an open area on the west side of the Solids Handling Building.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 9-3
TF
Humus
Primary
Clarifier
Primary
Solids
4.9%TS-
Grinder
Cr -
3.5%TS
TWAS
Dissolved
Air
Flotation
WAS
Final
Clarifier
BLACK & VEATCH
COIDOIIII011
Grinder
d
Primary
Anaerobic
Digestion
' 1
70' dia
(987,400 gal)
Grinder
Primary
Anaerobic
Digestion
2
45' dia
(329,100 gal)
Grinder
Primary
Anaerobic
Digestion
3
45' dia
(329,100 gal)
1,645,600 gal Total
Secondary
Digester
40' dia
(217,100 gal)
Secondary
Digester
2
40' dia
(217,100 gal)
Secondary
Digester
3
40' dia
(217,100 gal)
650,000 gal Total
Grinder
Polymer
(28 Ib/dt)
Centrifuge No.
■I
� f
(240 gpm
Biosolids)
Centrate Well
To South Lagoon
21-22% TS
Truck Load Out
YAKIMA WWTP
CURRENT BIOSOLIDS TREATMENT PROCESS Figure 9-1
132965.1400•^ ''1I 12/2/03
9.6 Expansion and Upgrade Requirements
The existing solids processes have adequate capacity for the current solids production;
however, some of the processes do not have adequate standby capacity in the event of an
equipment failure. In addition, future increases in solids quantities may require
additional process capacity. Based on the capacity evaluation and standby requirements
presented in Section 5, the following processes are recommended for expansion and are
discussed in this section:
• WAS Thickening
• Anaerobic Digestion
• Dewatered Cake Storage
• Centrate Treatment or Equalization
• Dewatering
Order -of -magnitude capital costs were developed for each of these expansions or upgrades.
Contingencies, and engineering, legal and administrative costs were applied to capital costs
at a rate of 30 percent and 25 percent, respectively.
Based on workshops with plant staff, several alternatives were selected for the expansion or
alteration of the biosolids processes listed above. These alternatives were evaluated based
on,present worth over the 20 year project life, at an interest rate of 5 percent. Qperation
and_inaintenanne osts were based on average solids quantities of 12.4 dtpd before digestion
and 7.4 d.:s.1 digestion. These values represent projected so' iid q antities at 2014,
which is halfway through the project life and assumed a total solids destruction of 40
percent through mesophilic digestion. Operations and maintenance costs were developed
based on the following unit costs:
• Power
• Labor (Operator/Maintenance)
• Polymer
• Natural Gas
• Sulfuric Acid
• Sodium Hydroxide
• Sodium Hypochlorite
• Cake Hauling
• Land Application
$0.037/kWh
$30/hr (including benefits)
$1.50/lb on dry weight basis
$5.00 per MM Btu
$1.00/gal (for assumed new odor control)
$2.10/gal (for assumed new odor control)
$1.00/gal (for assumed new odor control)
$5.80/cy
$15/wt (2003 cost)
Unit costs for land application, labor, and power were provided by plant staff. Costs for
natural gas, sodium hypochlorite, and sodium hydroxide were based on typical national
costs. Hauling costs were calculated based on mileage to NSF, the reported labor rate, and
typical fuel costs. New facilities were expected to have a 60 percent salvage value at the
end of the 20 -year project life.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-5
9.6.1 Dissolved Air Flotation Thickening
The existing DAFT unit has adequate capacity through the 2024 design period; however,
the single DAFT unit has no standby capability. Therefore, the City should consider
,__installing a second 45 foot diameter -DAFT unit While on 5 one�nit-would be Operated
at a time, ope111 1hou1d"6e alternated to ensure that both units stay in working order.
The DAFT unit will be covered and odor controlled. Odor control option costs will be
affected by DAFT siting and operating frequency and should be evaluated during design
to determine the most cost effective technology. It was assumed for this evaluation that
separate odor control will be provided for the new DAFT. The DAFT expansion includes
the following new facilities:
• New 45 foot diameter covered DAFT tank
• New DAFT mechanical equipment (includes saturator, receiver, and ancillary
equipment)
• New 1,900 sf metal building for DAFT mechanical equipment and controls
• New odor control system
It is recommended that the existing dry polymer feed system be dedicated to DAFT
treatment. The estimated project cost for a new DAFT system is $2.0 million. Detailed
costs are presented in Table 9-3.
Table 9-3
Dissolved Air Flotation Thickening — Estimated Cost for Second, Standby Unit
Item Description
Opinion of Probable Cost
DAFT basin and equipment
$700,000
DAFT equipment building
$230,000
Odor control system
$143,000
Sitework (10% of building cost)
$23,000
Electrical
$161,000
Subtotal
$1,257,000
Contingency (30%)
$377,000
Subtotal
$1,634,000
Engineering, Legal, and Administration (25%)
$409,000
Total Opinion of Probable Cost
$2,043,000
9.6.2 Anaerobic Digestion
Anaerobic digestion systems are typically designed to meet detention requirements with
one primary tank out of service, which allows tank cleaning or maintenance. Based on
the maximum month solids projections presented in Section 9.3, if the large primary
digester (1.0 MG) is taken out of service, the remaining tankage (primary and secondary)
can not provide 15 days of detention to meet Class B pathogen criteria. An additional 0.6
MG of primary digester tankage is required to meet the 15 day criteria with the large tank
out of service during maximum month solids production at 2024 conditions. This
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-6
additional volume requirement assumes that the existing secondary digesters can be
converted to function as primary digesters if needed. If secondary digesters are not used
as backup primary capacity, the primary digester requirement increases to 1.3 MG at
2024 conditions. Two alternatives for providing the required volume for 2024 solids
quantities are discussed in the following sections.
9.6.2.1 Add Primary Tankage, Retrofit Existing Secondary Tanks
This alternative requires adding some primary digester tankage, but minimizes the new
tankage requirements by using the existing secondary tanks as primary digesters when the
large 1.0 MG primary digester is not in operation. The secondary digesters are not
currently equipped with heat exchange equipment. Therefore, heat exchangers and
required ancillary equipment should be installed for each of the secondary digesters to
provide primary digestion capacity in the event that the large primary digester is out of
service. The digester expansion includes the following new facilities:
• One new primary digester with fixed cover, with a minimum volume of 0.6 MG
• Mixing, recirculation, and heat exchange equipment for new digester
• Heat exchange and recirculation equipment for each of three secondary digesters
The estimated project cost for a new anaerobic digester and heat exchange retrofit to the
secondary digesters is $3.4 million. Detailed costs are presented in Table 9-4.
Table 9-4
Estimated Cost to Expand Mesophilic Digestion with Secondary Digester Backup —
for 2024 Conditions
Item Description
Opinion of Probable Cost
Digester tankage and mixing equipment
$1,180,000
Heat exchangers for secondary digesters
$330,000
Grinders for secondary digesters
$90,000
Piping modifications
$100,000
Sitework (10% of new tank and piping cost)
$128,000
Electrical
$255,000
Subtotal
$2,083,000
Contingency (30%)
$625,000
Subtotal
$2,708,000
Engineering, Legal, and Administration (25%)
$677,000
Total Opinion of Probable Cost
$3,385,000
9.6.2.2 Add Primary Tankage
The second evaluated option provides adequate primary tankage to support primary
digestion requirements with the existing large (1.0 MG) primary tank out of operation.
This option requires a new, 1.3 MG primary digestion tank, equipped with heating and
mixing.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-7
The estimated project cost for a new anaerobic digester is $5.4 million. Detailed costs
are presented in Table 9-5. Although having a higher capital cost, this digestion
alternative provides the most flexibility for dewatering operation and far less complicated
construction phasing compared to retrofitting the secondary digesters.
Table 9-5
Estimated Cost to Expand Mesophilic Digestion with New Primary Digester
Tankage—for 2024 Conditions
Item Description
Opinion of Probable Cost
Digester tankage and mixing equipment
$2,600,000
Piping modifications
$50,000
Sitework (10% of new tank and piping cost)
$265,000
Electrical
$398,000
Subtotal
$3,313,000
Contingency (30%)
$994,000
Subtotal
$4,307,000
Engineering, Legal, and Administration (25%)
$1,077,000
Total Opinion of Probable Cost
$5,384,000
9.6.3 Dewatered Cake Storage
Dewatered cake from the centrifuges is discharged into trucks and hauled to the NSF
BUF. Plant staff has indicated that inclement weather can interfere with hauling
operations during the winter. Dewatered cake storage would provide temporary on-site
storage for the dewatered cake during these periods. Due to potential odor issues
associated with a cake storage facility, the facility should be covered and odor controlled.
Based on input from plant staff, the cake storage facility was sized to provide three weeks
of storage at 2024 average conditions and enclosed storage for up to five trailers.
A cake storage facility would require the following:
• 12,700 sf enclosed facility with odor control for cake storage
• 4,000 sf enclosed facility for trailer storage
The estimated project cost for a cake storage facility is $1.9 million. Detailed costs are
presented in Table 9-6.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-8
Table 9-6
Cake Storage Facility—for 2024 Conditions
Item Description
Opinion of Probable Cost
Enclosed cake storage
$406,000
Odor control for cake storage
$450,000
Enclosed trailer storage
$128,000
Sitework (10% of construction cost)
$53,000
Electrical
$148,000
Subtotal
$1,185,000
Contingency (30%)
$356,000
Subtotal
$1,541,000
Engineering, Legal, and Administration (25%)
$385,000
Total Opinion of Probable Cost
$1,926,000
9.6.4 Centrate Equalization or Treatment
The Yakima Regional WWTP currently operates a single centrifuge approximately two
days per week to dewater digested solids and returns centrate to the head of the plant for
treatment in the liquid process. Based on the current centrifuge operation, large
quantities of centrate are produced in a relatively short time. Typically, centrifuges
operate on a five- to seven-day schedule, minimizing the impact of centrate return on the
liquid stream treatment processes. Since centrate has high concentrations of ammonia,
nutrient loads from returned centrate can overload the liquid treatment process.
The liquid treatment process at the Yakima plant is able to receive and treat the centrate
loads during normal loading conditions. However, during several months each fall, the
plant receives large amounts of BOD from Del Monte fruit processing discharge. Due to
a high BOD/low nitrogen feed, nitrification becomes limited in the liquid treatment
process. Consequently, the centrate return must be equalized over the work week to
avoid ammonia break -through in the effluent. Centrate is culTently equalized through the
south lagoon; however, if this lagoon is decommissioned as planned, the City must either
provide a new equalization facility, treat the centrate prior to its return, or operate the
centrifuges for a longer period at a lower feed rate, reducing the rate of centrate
production.
Of the three options listed above, operating the centrifuges for a longer period at a lower
feed rate is the least expensive option, requiring no modifications to the existing
facilities. However, this may not be desirable based on plant staffing requirements.
Sidestream treatment of the centrate would consist of a separate activated sludge facility
to nitrify the centrate prior to its return to the plant liquid treatment processes, with
microorganisms supplied by using RAS from the main activated sludge process.
However, since the activated sludge process has difficulty maintaining nitrification in the
fall, the RAS from the main treatment plant would not be able to support nitrification in
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 9-9
the sidestream treatment. Since the sidestream treatment would not provide dependable
ammonia removal throughout the year, it is not considered further.
Equalization of the centrate would require tankage providing at least three days of
storage. This would allow the centrate return to be spread from two days to five days,
minimizing its impact on the liquid treatment process. To allow further operational
flexibility and capability to meet effluent quality requirements, it is recommended that at
least six days worth of storage be provided. Currently, the centrate is diluted with water
to minimize struvite formation; however, this significantly increases the storage volume
requirements. Therefore, ferric feed has been included in this option to address potential
struvite formation. The ferric system should be capable of feeding ferric at the digester
and upstream of dewatering. For this evaluation, it was assumed that the storage tanks
would be supported by existing odor control treatment. Equalization and struvite control
would require the following:
• 700,000 gallons of storage tanks
• Pump mixing for the tanks
• Piping modifications
• Ferric feed for struvite control
The estimated project cost for a centrate equalization facility is $1.5 million. Detailed
costs are presented in Table 9-7. An additional cost will be the decommissioning of the
South Lagoon. An estimated cost for removing and disposing of the solids contained in
the lagoon is $111,000. This cost may vary considerably based on available outlets for
the material and required material characteristics.
Table 9-7
Estimated Cost to Provide Centrate Equalization Tankage—for 2024 Conditions
Item Description
Opinion of Probable Cost
Centrate Storage Tanks
$700,000
Piping modifications
$50,000
Ferric feed for struvite control
$40,000
Sitework (10% of construction cost)
$79,000
Electrical
$63,000
Subtotal
$932,000
Contingency (30%)
$280,000
Subtotal
$1,212,000
Engineering, Legal, and Administration (25%)
$303,000
Total Opinion of Probable Cost
$1,515,000
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 9-10
9.6.5 Dewatering
The current dewatering facility at the Yakima Regional WWTP has a single operable
centrifuge, installed in 1992. No standby dewatering equipment is available. Plant staff
has also identified problems with the existing dewatering facility. Some of these issues
are as follows:
• Existing screw conveyor system is difficult to access and maintain
• No standby dewatering capacity is available
• Existing truck load out is performed outside the dewatering building and may be a
source of odors
• Existing centrifuge layout is extremely tight, making machine access difficult
• Current polymer feed system only allows use of dry polymer
• Single polymer system feeds both thickening and dewatering — both processes can
not be supported simultaneously.
Dewatering technologies that were considered included belt filter press, centrifuge, and
screw press dewatering. Based on staff input, belt filter press dewatering was eliminated
due to concerns with dewatering room odors and operator attention requirements.
Centrifuge and screw press dewatering were retained for further evaluation.
Several dewatering alternatives were considered. These included options that ranged
from replacing the inoperable centrifuge to the construction of a new Solids Dewatering
Building with an enclosed truck load out area. The minimum requirement for each of
these alternatives was to replace the inoperable centrifuge to provide standby capacity. It
is also recommended that a new polymer feed system be installed to allow simultaneous
operation of the DAFT and the centrifuges, which will be required before the end of the
20 year project life. Se.arate ,ol mer s stems for thickenin• and dew.t
different polymers to be used for each process, increasing flexibility and the ability to
optimize polymer selection for the different processes.
The three dewatering alternatives selected for further evaluation are as follows:
•
• Dewatering Alternative 1 — Replace inoperable centrifuge, add new dewatering
polymer system, provide odor control for
dewatering area
• Dewatering Alternative 2 — Construct new dewatering facility with truck load
out, relocate existing operable centrifuge, install
new second centrifuge
• Dewatering Alternative 3 - Construct new dewatering facility with truck load
out, install new screw press dewatering.
Descriptions of these alternatives are presented in the following sections. Present worth
costs, including order -of -magnitude capital costs and O&M costs, were developed for
each alternative for a 20 -year project life.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-11
9.6.3.1 Dewatering Alternative 1-- Replace Centrifuge
This alternative continues to use the existing Solids Building. It replaces the inoperable
centrifuge with a model that provides similar capacity to the existing DS -705 machine.
Based on input from the plant staff, the existing conveyance system is old and requires
frequent repair. Due to the restricted area available for conveyance, the existing screw
conveyor system will be replaced with new, similar conveyors. No changes will be made
to the existing truck load out area for this alternative. An expansion to the north side of
the building will house a new polymer feed system dedicated to centrifuge dewatering.
Plant staff has also indicated that while the centrifuges and screw conveyors are currently
equipped with odor control, fugitive emissions from the dewatering system have caused
odor problems in the dewatering building. Therefore, a new carbon odor control system
has been included in the cost of this alternative. However, it is strongly recommended
that an odor evaluation be performed to determine the actual source of the odors and the
most cost effective odor control method prior to design of an odor control system for the
dewatering facility.
This alternative includes the following:
• New high solids centrifuge
• Grinder for new centrifuge
• Feed pump for new centrifuge
• Odor control for dewatering area
• Replacement dewatered cake screw conveyor system
• New dry/emulsion polymer system
• 900 sf addition for new polymer system
• New door in existing Solids Building for ease of centrifuge replacement and
maintenance.
It should be noted that the existing centrifuge was installed in 1992 and is approximately
half way through its projected 20 year life. An estimated future cost for replacing the
existing centrifuge has been included in this evaluation based an estimated current cost of
$1,196,000.
Based on current centrifuge capacity, a single centrifuge operated 24 hours per day, 79
days per year should be able to dewater projected annual average solids quantities at
2014. O&M power and labor costs were based on the 79 day operation. Polymer use
costs were based on the current polymer dosage of 28 lb/dt. Hauling and land application
costs were based on generating 20 percent cake solids. The present worth cost for this
alternative is $10.7 million. Detailed costs are presented in Table 9-8.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-12
Table 9-8
Estimated Cost for Dewatering Altet native 1— Replace Centrifuge
Item Description
Opinion of Probable Cost
New centrifuge
$500,000
Centrifuge installation/removal existing
$120,000
New door for dewatering building
$200,000
Grinders
$35,000
New polymer feed area
$108,000
Polymer system
$200,000
Feed pumps, installed
$20,000
Replacement cake conveyor system
$246,000
Dewatering area odor control
$162,000
Bridge crane for polymer system
$75,000
Sitework (10% of building cost)
$11,000
Electrical
$232,000
Subtotal
$1,909,000
Contingency (30%)
$573,000
Subtotal
$2,482,000
Engineering, Legal, and Administration (25%)
$621,000
Total Opinion of Probable Cost
$3,103,000
Annual Operating Costs
$/yr
Power
$15,000
Labor
$66,000
Polymer
$113,000
Odor Control
$24,000
Equipment Maintenance
$30,000
Hauling
$98,000
Land Application
$203,000
Total, Operating Costs
$549,000
New Centrifuge in 2014 (net present value)
8734,000
Total Net Present Worth, $
$10,655,000
Annualized Unit Cost, $/dt
$189
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-13
9.6.3.2 Dewatering Alternative 2— New Centrifuge Dewatering Building
This alternative continues to use centrifuge dewatering, but includes a new Solids
Dewatering Building. A new centrifuge with capacity similar to the existing DS -705
machine will be provided. The existing DS -705 machine will be moved from its current
location to the new dewatering facility. Odor control is provided for the centrifuges and a
new polymer feed system is provided. An enclosed truck load out area with odor control
is provided. This alternative includes the following:
• New high solids centrifuge
• Grinders for new and relocated centrifuges
• Feed pumps for new and relocated centrifuges
• New centrate pump station
• Dry/emulsion polymer system
• 10,400 sf dewatering facility
• 1,600 sf truck load out facility
• Screw conveyor system for dewatered cake
• Odor control for centrifuge dewatering
• Odor control for truck load out area
As discussed, the existing centrifuge was installed in 1992 and is approximately half way
through its projected 20 year life. Similar to Alternative 1, an estimated future cost for
replacing the existing centrifuge has been included in this evaluation based an estimated
current cost of $1,196,000..
Based on current centrifuge capacity, a single centrifuge operated 24 hours per day, 79
days per year should be able to dewater projected solids quantities at 2014. O&M power
and labor costs were based on the 79 day operation. Polymer use costs were based on the
current polymer dosage of 28 lb/dt. Hauling and land application costs were based on
generating 20 percent cake solids. The present worth cost for this alternative is $13.4
million. Detailed costs are presented in Table 9-9.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-14
Table 9-9
Estimated Cost for Dewatering Alternative 2 — New Centrifuge Dewatering Building
Item Description
Opinion of Probable Cost
Centrifuge
$500,000
Centrifuge installation
$100,000
Centrifuge re-siting
$120,000
Grinders
$70,000
Solids building
$1,248,000
Truck load -out
$192,000
Conveyors
$216,000
Cranes/hoists
$150,000
Polymer system
$200,000
Feed pumps, installed
$50,000
Centrate pump station
$120,000
Odor control system
$200,000
Sitework (10% of building cost)
$144,000
Electrical
$442,000
Subtotal
$3,752,000
Contingency (30%)
$1,126,000
Subtotal
$4,878,000
Engineering, Legal, and Administration (25%)
$1,220,000
Total Opinion of Probable Cost
$6,098,000
Annual Operating Costs
$/yr
Power
$19,000
Labor
$66,000
Polymer
$113,000
Odor Control Chemicals
$22,000
Equipment Maintenance
$35,000
Hauling
$98,000
Land Application
$203,000
Total, Operating Costs
$556,000
New Centrifuge in 2014 (net present worth)
$734,000
Total Net Present Worth
$13,435,000
Annualized Unit Cost, $/dt
$238
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-15
9.6.3.3 Dewatering Alternative 3 — New Screw Press Dewatering Building
This alternative replaces the existing centrifuge dewatering with screw press dewatering
in a new Solids Dewatering Building. Screw press capacity, polymer use, and cake solids
were based on pilot testing conducted at the Yakima Regional WWTP by FKC Co., Ltd.
Screw press power consumption and floor space requirements were also based on
information provided by FKC Co., Ltd. Odor control is provided for the screw press
equipment and a new polymer feed system is provided. An enclosed truck load out area
with odor control is provided. This alternative includes the following:
• Three screw press systems (including floc tank, rotary drum thickener, and screw
press)
• Three feed pumps
• Pressate pump station
• Dry/emulsion polymer system
• 14,250 sf dewatering facility
• 1,600 sf truck load out facility
• Screw conveyor system for dewatered cake
• Odor control for screw press dewatering
• Odor control for truck load out area
Based on reported screw press capacity, two screw presses operated 24 hours per day,
260 days per year should be able to dewater projected solids quantities at 2014. O&M
power and labor costs were based on the 260 day operation. Polymer use costs were
based on a polymer dosage of 18 lb/dt reported in the pilot study results. Hauling and
land application costs were based on producing 18 percent cake solids, as reported in the
pilot test results. The present worth cost for this alternative is $16.7 million. Detailed
costs are presented in Table 9-10.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-16
Table 9-10
Estimated Cost for Dewatering Alternative 3 —New Screw Press Dewatering
Building
Item Description
Opinion of Probable Cost
Screw press equipment
$1,489,000
Press installation
$300,000
Solids building
$1,710,000
Truck load -out
$192,000
Conveyors
$288,000
Cranes/hoists
$150,000
Polymer systems
$200,000
Feed pumps, installed
$60,000
Centrate pump station
$120,000
Odor control system
$200,000
Sitework (10% of building cost)
$190,000
Electrical
$661,000
Subtotal
$5,560,000
Contingency (30%)
$1,668,000
Subtotal
$7,228,000
Engineering, Legal, and Administration (25%)
$1,807,000
Total Opinion of Probable Cost
$9,035,000
Annual Operating Costs
$/yr
Power
$16,000
Labor
$156,000
Polymer
$73,000
Odor Control Chemicals
$22,000
Equipment Maintenance
$45,000
Hauling
$109,000
Land Application
$225,000
Total, Operating Costs
$646,000
Net Present Worth, $
$16,656,000
Annualized Unit Cost, $/dt
$295
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-17
9.6.3.4 Dewatering Alternative Summary and Recommendation
Costs for the evaluated dewatering alternatives are presented in Table 9-11. Unit costs
were developed based on the average annual raw solids quantity projected for 2014 of
12.4 dtpd.
Table 9-11
Summary of Dewatering Alternative Costs'
Alternative
Project
Cost
($ millions)
Annual
O&M
(2014)
($ millions/yr)
Present
Worth
($ millions)
Unit Cost
(2014)
($/dt)
Alternative 1 — Replace
Centrifuge
$3.10
$0.55
$10.66
$189
Alternative 2 —New Centrifuge
Dewatering Building
$6.10
$0.56
$13.44
$238
Alternative 3 — New Screw Press
Dewatering Building
$ 9.04
$0.65
$16.66
$295
'Order -of -magnitude costs for co nparison of alternatives
Alternative 2 — New Centrifuge Dewatering Building — is the recommended option. This
alternative addresses the staff's concerns with the existing dewatering facility and
provides back up capability. However, its present worth of $13.44 million is more than
20 percent greater than the cost of Alternative 1 — Replace Centrifuge. Consequently, if
funds are not available to construct a new dewatering facility, Alternative 1 should be
considered.
Alternative 1 — Replace Centrifuge — is the least expensive dewatering alternative. While
this alternative provides back up dewatering, it does not address all of the concerns with
the existing dewatering system. The tight layout of the existing equipment makes
maintenance access difficult for the centrifuges and the dewatered cake conveyance
system. In addition, this alternative does not modify the open cake load out area, which
may be a source of odors.
9.7 Class A Treatment Alternatives
Several alternatives were considered for converting the Yakima Regional WWTP solids
treatment facilities to meet Class A pathogen criteria. These included the following
treatment technologies:
• Composting
• Advanced digestion
• Alkaline stabilization
• Heat drying.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-18
The benefits and drawbacks of each alternative were presented and discussed with plant
staff during a biosolids workshop and are presented below:
9.7.1 Composting
Composting produces a humus -like material from dewatered cake that can be used as a
soil amendment. Composting is a Process to Further Reduce Pathogens (PFRP), meeting
Class A pathogen requirements through time and temperature. Composting requires the
addition of amendment to increase the porosity of the compost and to improve the carbon
to nitrogen ratio. Amendment, typically yard waste or wood chips, significantly increase
the amount of material requiring transport and ultimate disposal. Composting operations
require adequate aeration to prevent odor problems. Sufficient oxygen can be provided
through forced aeration with blowers or by turning the compost pile (windrowing). The
type of aeration method dictates the physical configuration of the compost operation.
There are several different composting methods available. Two of these — aerated static
pile and windrowing — require significant amounts of land. Even with aeration, odors
from these methods can be problematic and require that the facility be completely
enclosed with odor control equipment.
A mechanical, or in -vessel, composting system has a smaller footprint than the static pile
or windrow methods; however, the capital cost is greater. The in -vessel system uses
forced air to keep the compost aerobic. Some systems also use mechanical agitation of
the compost within the closed containers. The odor control systems required for in -vessel
composting are smaller than those used for static pile or windrow systems. Several
manufacturers provide in -vessel composting equipment.
Advantages and Disadvantages
Compost is a marketable product and can be sold for a nominal fee that helps to reduce
product distribution costs. Composting can use yard waste generated by residents as an
amendment in a co -composting operation, potentially decreasing yard waste disposal
costs. However, the 2,600 tons per year of yard waste generated by City residents can
not meet the needs of a composting operation and additional amendment would need to
be purchased, significantly increasing the operating costs for this treatment method.
A major disadvantage of composting is the space requirement. Composting is a land -
intensive process that would need to be performed at an off-site location due to land
requirements. An area of six to ten acres would be required to support the solids
generated at the Yakima Regional WWTP. Off-site processing requires hauling
dewatered cake, creating a potential odor source. Due to odor issues associated with
static pile and windrow composting, enclosure and odor control would be recommended
for all type of composting operations for the Yakima plant. The procurement of an
experienced broker for the composted product marketing has also been crucial to the
success of other installations.
Based on site requirements, multiple operating locations, and odor potential, composting
was not retained for further evaluation.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-19
9.7.2 Advanced Digestion
Anaerobic digestion has traditionally been used to produce a Class B product; however, it
is beginning to be used to generate Class A biosolids. These processes are often referred
to as Advanced Anaerobic Digestion. Several different treatment configurations combine
high-temperature stages (thermophilic treatment) with the conventional mesophilic
anaerobic treatment to meet the Class A time and temperature requirements for pathogen
destruction. Class A digestion processes produce cake that has similar physical
characteristics as conventional digestion and is therefore suited to bulk land application.
There are a number of configurations that have been used for different advanced
digestion processes, selected based on process objectives, available space, and existing
tankage. Only configurations that include one or more thermophilic stages have reliably
met Class A pathogen criteria. Even when operated at thermophilic temperatures,
continuously fed, completely mixed digesters do not satisfy the Part 503 time and
temperature requirements for Class A criteria which require operational assurance that
every particle receives the required treatment. A few continuously fed thermophilic
systems, such as the Ondeo-Degremont 2 -PAD system, have received site-specific Class
A approval; however, only systems that include a batch thermophilic stage meet the Class
A criteria by definition and can be assured USEPA approval.
Temperature staged digestion, with at least one stage of thermophilic treatment, has been
implemented in a number of configurations. To address the "every particle" issue,
temperature phased anaerobic digestion (TPAD) uses semi -batch thermophilic tanks
upstream of mesophilic digestion. To support continuous feed, at least two semi -batch
tanks are required, so that one tank can receive raw solids while the second tank treats the
solids to the time and temperature requirements. The recommended TPAD system
configurations require a minimum SRT of 5 days in the thermophilic stage and 8 days in
the mesophilic stage.
Advantages and Disadvantages
TPAD digestion produces a Class A product; however, since the physical characteristics
are similar to conventionally digested biosolids, final use is still limited to bulk land
application. This limits the potential outlets for the solids; however, it also means that
the generated solids will be a good fit with the current land application program. In
addition, advanced digestion is similar to Yakima's existing solids treatment processes,
resulting in minimal changes to current operating practices. Thermophilic digestion has
been reported to affect dewatering characteristics, typically improving dewaterability.
However, thermophilically digested biosolids have been reported to release more odors
during dewatering than mesophilic biosolids, increasing odor control requirements. Since
advanced digestion processes are relatively new, extensive information on characteristics
of thermophilically digested solids is not yet available. Heat recovery is used to
minimize energy requirements for thermophilic digestion; however, energy use for a
TPAD system is greater than for conventional mesophilic digestion.
Advanced digestion using a TPAD configuration was retained for further evaluation.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-20
9.7.3 Alkaline Stabilization
Alkaline stabilization uses alkaline materials, such as quicklime, to treat dewatered
biosolids. Alkaline stabilization can be used to produce Class A or Class B biosolids,
depending on the quantity of chemicals used. The chemical reaction of the dewatered
biosolids with the alkaline agent generates heat, meeting pathogen reduction
requirements. The resulting product typically has a low nutrient content due to dilution
and loss of ammonia. Typical biosolids require approximately one pound of lime per
pound of solids for Class A treatment.
Several proprietary alkaline stabilization processes are available that meet Class A
treatment requirements. These include N-Viro, Bioset, RDP, and FKC. All of these
processes use lower lime dosages than "high lime" treatment processes, but may require
supplemental heat to meet the Class A temperature criteria.
Advantages and Disadvantages
The biggest advantage to alkaline treatment is the low capital cost compared to other
forms of Class A treatment. In addition, the alkaline stabilization process has a low level
of complexity compared to other stabilization methods. However, the chemical addition
required for alkaline stabilization significantly increases the ultimate quantity of
biosolids. Consequently, alkaline stabilization usually has high operating costs, due to
high chemical usage and increased hauling and distribution costs.
Alkaline treated material is essentially a liming agent, similar to agricultural lime. Unless
agricultural lime is used in significant quantities in the Yakima area on crops where it
will be generally acceptable, it will be difficult to find land application sites for lime -
treated biosolids. Based on conversations with the Washington Extension Service, little
agricultural lime is used in the region around Yakima and it is judged unlikely that
markets for the lime -treated biosolids can be easily identified in the local or regional area.
Another disadvantage of this process is that ammonia is released in significant quantities
upon alkaline addition and in lesser quantities during storage, potentially requiring odor
control for the treatment area and the truck loading area. In addition, the lime used in
alkaline stabilization tends to create dust problems in the treatment facility.
Based on the expected difficulty in identifying long-term land application sites for a lime -
treated product, alkaline stabilization was not retained for additional evaluation.
9.7.4 Heat Drying
Heat drying is a PFRP, meeting Class A pathogen requirements by drying the biosolids to
90 percent or greater. There are approximately 25 municipal heat drying installations in the
U.S., where biosolids are being dried for distribution or disposal. Heat drying greatly
reduces the plass and improves the materials handling characteristics of biosolids. Different
drying technologies are available to produce different types of dried product — granular and
pelletized. Direct dryers, used to produce pelletized product, are usually targeted at medium
to large -size installations. The majority of the pelletized drying installations employ a
direct -contact, rotary drum dryer and related materials conveyance, screening, and back -mix
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04
Page 9-21
equipment to enable production of a uniform, durable, pellet product. Final use is often
dependent on the pellet size. Screening can be used to produce various grades of product
that can be targeted to specific markets.
By pairing heat drying with anaerobic digestion, at least some portion of the gas
produced from digestion can be used to meet the energy requirements for heat drying.
Approximately 50 percent of the heating demand for drying can be supplied by the excess
gas from anaerobic digestion, depending on the operation scheme of the drying system
and competing demands for the heat.
Advantages and Disadvantages
The major advantage of heat drying is that the final dried product is a valuable fertilizer
material that can be sold in bulk. While the value of the product has fluctuated due to
market supply conditions, it usually offsets transportation costs and may provide some
revenue towards operating costs. Drying processes result in the least total volume of any of
the listed treatment methods, and therefore minimizes truck traffic and hauling costs.
Drying equipment is capital intensive and has significant operating costs. Since the dryers
require natural gas and electricity, increases in energy rates can have a drastic effect on total
costs. The procurement of an experienced broker for the dried product marketing has also
been crucial to the success of other installations.
Heat drying was retained for further evaluation.
9.8 Selected Class A Treatment Alternatives
The Class A treatment alternatives selected for further consideration, advanced digestion
and heat drying, were evaluated to determine equipment and facility requirements to
support Yakima Regional WWTP solids production through 2024. System requirements
for both of these treatment alternatives were developed based on the assumption that the
recommended mesophilic digester improvements, consisting of a new 1.3 MG primary
digester as presented in Section 9.6.2, are iinplemented. The digester improvements
ensure that the plant can continue to produce Class B biosolids in the event that a portion
of the Class A treatment system is taken out of service for maintenance. This eliminates
the requirement of providing redundant Class A treatment processes, minimizing capital
costs for either Class A system. System requirements for these treatment alternatives are
presented in the following sections.
9.8.1 Class A Alternative 1 — Advanced Digestion
This alternative provides a TPAD system consisting of four semi -batch thermophilic
tanks, followed by two mesophilic tanks. Digested solids will continue to be dewatered
using the plant's dewatering equipment and land applied as a cake. The TPAD process
consists of a 12 -hour feed, 24-hour reaction, and 12 -hour draw down cycle for each of
four thermophilic tanks. Implementation of this system does not require additional
tankage; however, it requires conversion of four of the existing digester tanks to semi -
batch thermophilic tanks. The tanks identified for thermophilic conversion are primary
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-22
digesters 2 and 3 (0.33 MG each) and secondary digesters 1 and 2 (0.22 MG each).
Primary digester 1 (1.0 MG), the new 1.3 MG primary digester, and secondary digester 3
(0.22 MG) will be used for the mesophilic stage of the TPAD system. This configuration
provides an 8.5 day thermophilic SRT and a 19.6 day mesophilic SRT. This alternative
requires additional heat exchange equipment, piping modifications, and controls.
Mechanical mixing equipment in primary digesters 2 and 3 must be replaced to
accommodate fluctuating liquid levels in the semi -batch thermophilic processes. A new
digester control building is required to house the additional mechanical equipment.
Specific equipment and facilities include:
• 6,400 sf digester control building
• Four tube -in -shell heat exchangers and ancillary equipment for heat recovery and
sludge pre -heating
• Three spiral heat exchangers and ancillary equipment for secondary digesters 1,
2, and 3
• Five new thermophilic to mesophilic sludge transfer pumps
• Sludge recirculation pumps for secondary digesters 1, 2, and 3
• Removal of existing mechanical mixers in primary digesters 2 and 3
• Installation of new gas mixing in primary digesters 2 and 3 and secondary
digester 1
• Installation of new pumped mixing systems in secondary digesters 2 and 3.
The TPAD system would be operated continuously. O&M power, labor and energy
requirements were based on continuous operation. Solids destruction through digestion
was increased from 40 percent to 50 percent to reflect anticipated increases in volatile
solids destruction during thermophilic digestion. Hauling and land application costs were
based on continued land application at NSF and generation of 20 percent cake solids after
dewatering. The present worth cost for this alternative is $11.2 million. Detailed costs
are presented in Table 9-12. A schematic of a potential TPAD process is presented in
Figure 9-2.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-23
Table 9-12
Estimated Cost for Class A Alternative 1 —TPAD Process
Item Description
Opinion of Probable Cost
Equipment Building
$768,000
New sludge pumping
$120,000
New tank mixing
$1,006,000
Heat exchangers and heat recovery system
$700,000
Piping modifications
$100,000
Sitework
$87,000
Electrical
$403,000
Subtotal
$3,184,000
Contingency (30%)
$955,000
Subtotal
$4,139,000
Engineering, Legal, and Administration (25%)
$1,035,000
Total Opinion of Probable Cost
$5,174,000
Annual Operating Costs
$/yr
Power
$65,000
Labor
$125,000
Natural gas
$18,000
Equipment Maintenance
$36,000
Hauling
$82,000
Land Application
$170,000
Total, Operating Costs
$496,000
Net Present Worth, $
$11,181,000
Annualized Unit Cost, $/dt -
$198
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-24
Figure 9-2. Potential TPAD Digestion Arrangement
Thermophilic
,,131F/2�
Hex
Hex
r
Hex
115" F
131°F
Heat Recovery
150° F
Hex
Hex
1
Hex
Supplemental Heating Pre -Heating
96°F
50° F
Mesophilic
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-25
9.8.2 Class A Alternative 2 -- Heat Drying
This alternative provides a single rotary drum drying train to heat dry digested, dewatered
solids. The drying system is sized to operate four to five days per week, 24 hours per
day. The drying system, which includes a wet material bin, back mixing, drying, recycle
bin, pellet cooling, and pellet storage, is based on a single Andritz DDS -40 system.
Figure 9-3 shows a schematic of an Andritz heat drying system. It should be noted that
there are alternate dryer configurations, such as installing two, smaller capacity units,
which should be investigated should this alternative be further evaluated.
The dryer capacity design assumes 18 percent solids in the dewatered cake and 95
percent solids in the heat dried product. A new facility is included to house the drying
equipment. Specific equipment and facilities include:
• 1 DDS -40 rotary drum drying trains
• 6,900 sf dryer facility
• Screw transfer conveyor from dewatering to drying facility
• Pellet storage silos providing approximately 2 weeks storage
Based on dryer capacity, the dryer would be operated approximately 2.5 days per week,
24 hours per day to dry projected annual average solids quantities at 2014. O&M power
and labor costs were based on the 2.5 day per week operation. Energy requirements were
based on using available digester gas to partially offset purchased natural gas
requirements. Hauling and land application costs were based on continued land
application at NSF. While the dryer capacity was sized based on 18 percent TS in the
dewatered solids to ensure adequate capacity, the hauling and land application O&M
costs were based on 20 percent cake TS to reflect current data. The present worth cost
for this alternative is $19.0 million. Detailed costs are presented in Table 9-13.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-26
Table 9-13
Class A Alternative 2 — Construct New Heat Drying Facility
Item Description
Opinion of Probable Cost
Rotary drum drying train
$5,040,000
Dryer facility
$828,000
Dewatered cake transfer conveyors
$120,000
Sitework
$83,000
Electrical
$772,000
Subtotal
$6,843,000
Contingency (30%)
$2,053,000
Subtotal
$8,896,000
Engineering, Legal, and Administration (25%)
$2,224,000
Total Opinion of Probable Cost
$11,120,000
Annual Operating Costs
$/yr
Power
$51,000
Labor
$262,000
Natural gas
$140,000
Equipment Maintenance
$126,000
Hauling
$26,000
Land Application
$43,000
Total, Operating Costs
$648,000
Net Present Worth, $
$19,009,000
Annualized Unit Cost, $/dt
$337
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-27
Figure 9-3. Heat Drying Schematic
Recirculated Air
Comb. Air
Fuel
i
Furnace
Cake
Drum Drye
Mixer
A
Wet
Material
Bin
Pre -
Separator
To RTO
Fugitive
Dust
Collector
Vent to Dust Collector
Polycyclone
pi,
Process Fan
Condenser
Venturi
Scrubbe
To RTO
1
4
Wastewater
Wastewater Wastewater
4 to lOmm
j- Fines
Crustier
Recycle
Bin
9.8.3 Class A Alternative Recommendation
Screen w
•
Exhaust Fan
Vent to Dust Collector
Trash > 10mm
2 to 4mm
®Diverter
Valve
Pellet Cooler
4—
Pneumatic Transporter to Silo
The recommendation for a Class A Treatment alternative is based both on economic and
non -economic factors. Based on this evaluation, advanced digestion has a present worth
approximately 40 percent lower than that of heat drying. However, the advantages and
disadvantages listed in Sections 9.7.2 and 9.7.4, that is, the non -economic factors, are
also weighed when selecting a recommended option. The major advantages for each
option are listed below:
Advanced Digestion
• Continue current land application and management practices
• Treatment processes are similar to existing anaerobic digestion processes
Heat Drying
• Markets can be developed for dried product
• Heat drying significantly reduces volume of biosolids, minimizing truck traffic
and hauling
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-28
At this time, the combination of lower cost and the availability of a strong land
application program make advanced digestion the more attractive Class A option.
However,ue o continuing developments in treatment technology and posse e'bT changes
in the availability of sites for land application, these options should be re-evaluated if the
decision to move to a Class A process is investigated at a future date. 40 PO, 7
9.9 Regional Solids Management
The potential for developing a regional solids processing facility away from the Yakima
WWTP was discussed with staff in conjunction with the review of Class A alternatives.
Thermal drying is most amenable to a regional facility, in comparison to advanced
anaerobic digestion. A remotely located drying facility could receive dewatered solids
for processing; whereas a digestion facility will require the residuals in a liquid form.
Costs for transporting the liquid could be prohibitive, depending on the conveyance
distance.
The primary benefit of a regional facility would be the economies of scale for both
construction and annual O&M costs. However, regional facilities can be difficult to
implement because of the differing management and political goals of multiple agencies.
If Yakima decides to implement a drying process in the future, further investigation could
be given to developing a regional facility.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 9-29
SECTION 10
ANALYSIS OF EXISTING WASTEWATER
COLLECTION FACILITIES
10.1 Summary
Section 10 presents an analysis of the existing Yakima collection facilities and describes
the sanitary sewer system discharging to the Yakima Regional WWTP. An evaluation of
the collection system is currently being performed, so Section 10 remains unchanged
from the 2000 Draft Wastewater Facility Plan prepared by HDR Engineering Inc.
The evaluation will include updating the City's GIS database with new information about
new lines installed, as well as implementing a flow -monitoring project to determine
capacities and influences from Infiltration and Inflow (I1I) on the system. This project is
currently evaluating pipes 12 inch and larger and will be instrumental in planning for
growth and dealing with 111.
City of Yakima Wastewater Facility Plan — DRAFT 8/12/05 Page 10-1
DRAFT
City of Yakima
Mandatory Wastewater Facilities Plan
SECTION 10
Analysis of Existing Wastewater
Collection Facilities
October 2000
prepared by
Clint Dolsby
HDR Engineering, Inc.
reviewed by
John Koch
Tony Krutsch
City of Yakima
DRAFT
Table of Contents
10.1 Introduction 1
10.2 Existing Sanitary Sewer System 1
10.2.1 Sewer Lines 1
10.2.2 Sewage Lift Stations 4
10.2.3 Rudkin Road Pumping Station 5
10.3 Infiltration and Inflow 5
10.3.1 Previous Attempts at the Identification and Removal of Infiltration
and Inflow 6
10.3.2 1985/1986 Evaluation Program 8
10.3.2.1 Summary of Infiltration from the 1985/1986 Evaluation 9
10.3.2.2 Summary of Inflow 11
10.3.3 Current Infiltration/Inflow Evaluation 11
10.3.3.1 Nonexcessive Infiltration 14
10.3.3.2 Nonexcessive Inflow 14
10.3.3.3 Evaluation of Nonexcessive Infiltration and Inflow 14
10.4 Maintenance Considerations 16
10.4.1 Tracking the Collection System 16
10.4.2 Cleaning and Flushing 17
10.4.3 Treatment of Roots 17
10.4.4 Grease Removal 18
10.4.5 Television Inspection and Grouting Program 20
10.4.6 Rodding Techniques 20
10.4.7 Smoke Testing 21
10.4.8 Measurement of Flow and Identification of I/I 21
10.4.9 Spot Excavation and Repair 22
10.4.10Safety Concems 22
10.4.11Yards and Shops 23
10.4.12Equipment 23
10.5 Organizational Structure 23
10.6 Staffing Requirements 25
10.6.1 Collection System Tracking 25
10.6.2 Cleaning and Flushing 25
10.6.3 Treatment of Roots 26
10.6.4 Grease Removal 26
10.6.5 Television Inspection 26
10.6.6 Grouting Program 27
10.6.7 Smoke Testing 27
10.6.8 Spot Excavation and Repair 27
10.6.9 Safety Concerns 27
10.6.10Yards and Shops 28
10.6.11Lift Station Equipment 28
10.6.12Collection System Summary 28
10.7 Existing Stormwater Program 30
HDI? ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE r
DRAFT
10.8 EPA Phase II Storm Water Regulations 31
10.8.1 Guidelines for Development of Costs 37
10.8.2 Cost Impacts of a Stormwater Utility 37
10.8.3 Implementation 38
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE ii
DRAFT
City of Yakima
SECTION 10
Analysis of Existing Wastewater
Collection Facilities
10.1 Introduction
Conveyance facilities include collector sewers, trunk lines, force mains, transfer
structures, and pumping stations. Conveyance facilities range from simple collection
systems to complex networks of sewers and pumping stations such as those tributary to
the Yakima Regional Wastewater Treatment Plant (WWTP).
This Section on the existing Yakima wastewater conveyance facilities describes the
sanitary sewer system discharging to the Yakima Regional WWTP. Pumping stations,
sewer mains, and force mains are identified, and existing system inadequacies are noted.
The infiltration and inflow into the system; the current program for sewer system
rehabilitation; safety, and reliability and efficiency issues will be presented. This analysis
of the existing collection system is based on:
➢ Historical data that was used to calculate current estimates of the infiltration and
inflow into the collection system.
➢ Interviews and meetings with City staff that were performed to evaluate current
operation and maintenance activities and identify safety, reliability, and capacity
issues of current collection system operations.
10.2 Existing Sanitary Sewer System
The existing sanitary sewer system for the City of Yakima is limited to the system
maintained by the City which includes the interceptor serving the City of Union Gap.
Unincorporated areas adjacent to the City of Yakima are included, as the City currently
provides maintenance services to these areas.
10.2.1 Sewer Lines
The first sewers were constructed in Yakima in the 1890's in what is now considered the
downtown area. Various additions and extensions have been made to the system since
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000 PAGE I
DRAFT
this early beginning. A history of the types of material used in the construction of the
collection system sewers is presented in Table 10-1.
Table 10-1. Yakima Sewage Collection System Sewer Construction
Date
Prior to 1930
1930-1945
1945 -mid 1950s
mid 1950s -late 1960s
Since the late 1960s
Pipe Material
Vitrified Clay
Concrete
Concrete
Asbestos Cement and Concrete
Concrete, PVC
Joint Material
Mortar
Mortar
Mastic
Rubber Ring
Rubber Ring
Collection system personnel currently clean and maintain the 290 miles of sanitary sewer
lines in the system. These collection system lines convey the wastewater to the Yakima
Regional WWTP. Table 10-2 presents an inventory of the Yakima wastewater collection
system as taken from maps in 1999. The existing Yakima Regional WWTP collection
system is shown in Figure 10-1.
Table 10-2. Yakima Sewage
Basin Designation
A
13
C
D
E
F
Total
5" to 12"
180,880
322,041
187,377
57,303
541,733
45,926
1,335,260
Collection
15" to 18"
8,288
35,493
4,130
15,630
30,654
96,181
System Inventory
20" to 27" 30" to 48"
22,120
11,197
5,868
25,078
18,832
2,132
85,228
8,599
226
12,302
934
4,723
26,784
1. In linear feet.
Since the completion of the 1988 Comprehensive Plan for Sewerage System for the City
of Yakima, Washington, the sewage collection system total length has increased by
approximately 24 percent (296,200 feet). Pipelines 15 -inch and larger have increased in
total length by over 53 percent, while pipelines 12 -inch and smaller have increased by
only 19 percent.
HDI? ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 2
1)
0
A
$381
6
1500
SCALE
0 1500
3000
SCALE
LEGEND:
FEET
SANITARY SEWER PIPING
TIETON ORNE
SIERRA ESTATES
UFT STATION
WIDE HOLLOW ROAD
ZIER ROAD
n
STONEHEOGE UFT STATION
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LAKE ASPEN L.S.
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TAVARACK UFT STATION
W LINCOLN AVENUE
E YAKiMA AVENUE
N08
HILL BOULEVVD
S 16TH AVENUE
BEACH UFT STATION
INTERSTATE 82
RACE STREET
UFT STATION
K -MART
UFT STATION
AHTANUM ROAD
HDR Engineering, Inc.
1111
•
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATI.IENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLS BY
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Dote
FEBRUARY 2000
YAKIMA
REGIONAL WNTP
�"RUDKIN ROAD
F/ UFT STATION
1
RUDKIN ROAD
THIS UNE I5 ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
c
0
a
m
0
z
EXISTING
WASTEWATER
SERVICE
Flgure Number
10-1
DRAFT
In addition to the sewage collection system owned and operated by the City, each
individual property owner owns and is responsible for the maintenance of the building
sewer connection to the wastewater collection system. The property owner's building
sewer begins at, and includes, the tee/wye connection to the City's system, and ends at the
building drain of the structure being served. Building sewers represent an additional 218
miles of 4 and 6 -inch sewer pipelines to the City's collection system. Many building
sewers are as old as the oldest pipelines in the Yakima system, were not installed with as
much care as the mainline sanitary sewers, are located closer to the ground surface and
are more susceptible to damage, and have received less maintenance than the mainline
sanitary sewers over the past 100 years. Mainline collection system sewer lines are
installed at depths of 6 to 20 feet (typically approximately 10 feet). Building sewers are
typically installed at 5 feet in depth with many being less than 2 feet. A groundwater
depth of 10 feet has been used in infiltration evaluations and will affect the deeper
mainline before the building sewers.
10.2.2 Sewage Lift Stations
There are nine local sewage lift stations in the Yakima collection system. An inventory of
existing Yakima Urban Area lift stations is provided in Table 10-3. All of these stations
are tributary to the Yakima Regional WWTP.
Table 10-3. Yakima Sewage Lift Station Inventory)
Pump Station Name
Type of Station
Location Number of Capacity of each
Pumps unit (gpm)
• Tamarack
• Race
• Beach
• Carriage 1-1111
• Lake Aspen
• Stonehedge
• Sierra Estates
• K -Mart
• Lakeside
Submersible
Submersible
Vacuum
Dry Well Gravity
Centrifugal
Vacuum
Submersible Grinders
Submersible Grinders
Vacuum
Submersible
4th Street and P
15th Street and Race
Chalmers Street
46th Avenue
Aspen
66th and Scenic
96th and Tieton
Kmart
40th and Fruitvale
2
2
2
2
2
2
2
2
2
150
375
100
150
75
150
150
75
140
1. From personal Communication with Kim Webster. from the City of Yakima.
The Tamarack and Race Street lift stations have recently been rehabilitated. Two new
Flygt submersible pumps were installed at the Tamarack lift station and it was relocated
to 4th Street and P to accommodate service needs in the northeast area of the City. The
Race Street lift station was improved to provide greater reliability and capacity.
The K -Mart lift station has been experiencing constant grease problems and should be
replaced. The Beach lift station will also require rehabilitation.
Breakers in the control panels of some of the wastewater lift stations have experienced
tripping due to hot weather in the summer months. Shelters could be constructed to
provide shade, or some other method of cooling should be provided. The electrical panel
doors at some lift stations are 1 -inch off the ground causing high snow or rains to cause
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ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000 PAGE 4
DRAFT
tripping of breakers. Electric panels should be raised to provide a minimum of 3 feet
from the bottom of the panel to the existing ground.
Grease that flows through the Yakima wastewater collection system collects in the lift
stations and could be removed using a vactor cleaning system. From the vactor cleaning
system the grease would need to be dried in order to dispose of it. Presently, the City of
Yakima does not have a location for the material to be dried or a method for drying it.
The City has initiated a program with a local private operator to remove grease from the
lift stations with disposal to the Cheyne landfill.
The City of Union Gap and the Terrace Heights Sewer District discontinued operation of
their sewage treatment plants in 1980 and constructed sewage pumping stations and
pressure mains which are now connected to the Yakima Regional WWTP. They are
responsible for the operation and maintenance of these pumping stations and force mains.
Flow from the Terrace Heights Sewer District pumping station is discharged just prior to
the headworks of the Yakima Regional WWTP. Flow from the City of Union Gap
pumping station is discharged into the interceptor sewer near the Valley Shopping Mall,
which discharges to the Rudkin Road Pumping Station and from there, sewage is pumped
to the major collector box opposite the Yakima Regional WWTP. The Rudkin Road,
Union Gap, and Terrace Heights Pumping Stations are equipped with emergency
generators in the event of a power loss.
10.2.3 Rudkin Road Pumping Station
The Rudkin Road Pumping Station has a current capacity of 5.6 MGD. The City of
Yakima retains ownership of 42.3 percent of the pumping station capacity or
approximately 2.37 MGD. The City of Union Gap purchased the remaining 57.7 percent
capacity or 3.23 MGD. Current average daily flows during maximum month at the
Rudkin Road Pumping Station are approximately 2.8 MGD with an estimated peak daily
flow of approximately 3.50 MGD.
Wastewater enters the wet -well of Rudkin Road Pumping Station which is monitored for
water surface elevation. The dry -well of the pumping station contains two 35 HP, 1,200
gpm variable speed dry -pit submersible pumps, and two 77 HP, 2,700 gpm variable speed
dry -pit submersible pumps. As flow increases at the pumping stations the pumps are
brought on-line in series to transfer the flow to the Yakima Regional WWTP. An
emergency generator is available at the Rudkin Road Pumping Station for continuous
operation during a power outage.
10.3 Infiltration and Inflow
Infiltration is defined as extraneous water entering the sewer system as a result of the
height of the groundwater table, the type and tightness of the sewer joints, and the soil
type. Infiltration reduces the capacity of the sewer collection system available for
customers and increases the costs of treatment at the Yakima Regional WWTP.
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ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 5
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Inflow is generally associated with specific outside events such as rainfall, broken water
mains, street flushing, floods, irrigation system flushing, or similar situations. Inflow
enters the collection system through planned or devised connections or disposal of
unwanted extraneous flow into the collection system. Typical sources of inflow include
roof drains, cross connections with storm sewers or irrigation systems, yard and area
drains, and cooling water discharges.
10.3.1 Previous Attempts at the Identification and
Removal of Infiltration and Inflow
The City of Yakima has made several attempts to identify and seal sections of the sewer
lines with infiltration problems and eliminate identified inflows to the system.
Experience with previous sewer system studies and rehabilitation efforts are useful in
understanding the City's infiltration and inflow problems.
The first efforts to renovate the sewers in the Yakima System took place in 1960. Sewers
in the area bounded by Jerome Avenue, Garfield Avenue, 6th Avenue North and the
Fruitvale Canal were chemically sealed. The method used required bypassing the sewage
flow during the repair operation and extensive sewer line cleaning prior to sealing. The
sewers were filled with a slurry under a static head of approximately 4 feet above adjacent
groundwater so that it could penetrate the cracks and defective joints. The slurry was
drained from the pipe and a chemical solution was added which penetrated the previously
deposited slurry to form an impermeable plastic gel. Flow tests following the application
showed good results although the infiltration measured one year later was greater than
prior to sealing. This made it apparent that the sealant deteriorated over time and the
groundwater forced the newly placed grout out of the cracks and faulty joints.
In 1962, the City of Yakima conducted an infiltration and inflow study of six areas of
suspected extraneous flows to the sewer system. The study found that extraneous flows
resulted from leakage of the separate irrigation systems, a generally high groundwater
table, and from such direct inflow sources such as storm sewer connections. Based on the
study, a maximum of 14.8 mgd of extraneous flows to the sewage collection system was
estimated during the summer months. At least 4 mgd of this flow was directly related to
the use of woodstave irrigation systems. Summer flows of 22.4 mgd were reported at the
Yakima Regional WWTP during the study.
Between 1962 and 1969, Yakima tested several different sealing methods in search of a
satisfactory solution to its infiltration problems. In 1965, an external grouting process
was attempted in which the leaks were identified by a TV camera and grouting was
accomplished by drilling holes into the ground at the point of the leak. This method was
very time consuming and difficult because the gravelly soils required extensive amounts
of grout for effective sealing and was soon abandoned. In 1967, a sealing program using
a method developed by the Penetryn Company was attempted. This method was used on
several sewers in the area between Englewood Avenue and the Fruitvale Canal, and on
some sewer sections bounded by Jerome Avenue, Garfield Avenue, the Fruitvale Canal,
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ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 6
DRAFT
and 6th Avenue North. Several of these sewer sections were sealed in 1960. Leaks were
located by pulling a TV camera through the sewer lines. A packer was placed internally
at the location of the leaks with its sealing ring inflated. The packer forced an epoxy
sealing compound into the cracks or faulty joints. This rehabilitation program is reported
to have reduced the infiltration into the sewer system by several million gallons per day
during the 1967 irrigation season. During the summer of 1968, infiltration was observed
in the recently sealed sewers. A subsequent TV survey revealed that the sealing
accomplished in 1967 was in good condition, although new leaks had developed in
unsealed areas. These new leaks were most likely caused by the increase in external
water pressure on untreated cracks and joints which caused these areas to fail. Further
sewer sealing was undertaken in 1969 in the area between Englewood Avenue and the
Fruitvale Canal, and several sewer system sections were sealed in the alleys west of 5th
Avenue North, east of 1S` Avenue South, and east of Rock Avenue. This rehabilitation
was accomplished with acrylamide gel material.
The Penetryn Company TV inspected and sealed the sewers paralleling Mead Avenue
from approximately 6th Avenue South to 16`h Avenue South, and a percentage of the 8 -
inch laterals discharging to the trunk sewer in the vicinity of 12th Avenue South in 1972
and 1973. This sewer sealing program differed from the 1967 program in that all joints in
each leaky area were air tested, and both marginal and leaky joints were sealed. The
joints were air tested after they were sealed to insure good results.
Early infiltration control programs attempted by the City of Yakima prior to 1972 were
not permanent. Application techniques and materials were in their infancy of
development in the United States. Instead of a reliable method of chemically grouting
sewer lines, procedures used in these early programs could be more properly termed as
experimental. The 1972 rehabilitation effort was one of the first attempts made with what
is now considered as standardized equipment and materials using a comprehensive
rehabilitation program. Each joint in a section of the sewer line was tested and sealed.
Results of the 1972 program indicated a significant reduction of infiltration in the
collection system near the sealed area. Only 13 to 15 blocks of sewer system
rehabilitation were included in the 1972 program.
The infiltration/inflow investigations of the City of Yakima sewer system performed in
1974, and reported in the 1976 Sewer System Evaluation Survey, indicated that as much
as 13 mgd of the maximum daily flow recorded at the Yakima sewage treatment plant
might be due to infiltration and inflow into the sewer system. The 1976 report listed
specific sewer lines in the collection system contributing to infiltration and inflow.
Comments on the probable cause of the infiltration and inflow were provided. The
estimates of the infiltration/inflow quantities were based on differences in flow
measurements taken before irrigation system start-up, at the time of irrigation system
closure, and a third set of flow measurements taken from one to two weeks following
irrigation system closure.
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ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 7
DRAFT
The 1976 report concluded that approximately 60 percent of the infiltration and inflow
occurred in 15 percent of the system. Portions of Basin A and B, the older sewage
collection systems, were identified as the primary locations of much for this extraneous
flow.
In the 1976 Sewer System Evaluation Survey, the infiltration/inflow that could be
removed from the Yakima sewage collection system was estimated as 8.15 mgd using
methods of removal that would be nearly 100 percent effective. The General Irrigation
System was identified as the source of approximately 4.8 mgd of the infiltration and
inflow to the sewer system. The amount of infiltration/inflow that the 1976 report
estimated could be removed by different corrective measures is summarized as follows:
> 0.71 mgd by chemical sewer sealing
> 4.90 mgd by sewer relining
> 1.06 mgd by irrigation pipe relining
> 0.29 mgd by manhole repairs
> 0.80 mgd by removing industrial discharges from the sanitary sewers
> 0.39 mgd by various sewer and irrigation pipe repairs
The 1977/1979 rehabilitation program was intended to remove approximately 5.8 mgd of
extraneous flows from the collection system. Both chemical grouting and relining efforts
were included in the program. Based upon an analysis of the completed program
prepared in 1978, approximately 2 mgd of infiltration/inflow was most likely removed
from the system as a result of sewer rehabilitation. The analysis was not based on
intensive data collection and evaluation. The 1977/1978 program was the most extensive
rehabilitative effort undertaken by the City of Yakima to eliminate extraneous flows.
10.3.2 1985/1986 Evaluation Program
The City of Yakima sewerage system was evaluated from 1985 to 1986. The objective of
the evaluation program was to provide data for calibration of the sewer system model; to
identify the total amount of I/1; to identify the quantity of 1/1 occurring in each subbasin;
and to identify the specific sources of extraneous flow to the sewer system such as
irrigation systems, canals, high groundwater, rainfall, ect.
This evaluation program included the placement of continuous flow monitors at the
outlets of the major drainage basins and at major flow points within the basin. Spot flow
measurements were taken within the basins to isolate extraneous flow sources.
Three intensive flow measurement periods were selected to coincide with the shutdown
and startup of the irrigation systems, and the peak sewage influent period as recorded at
the Yakima Regional WWTP.
➢ Fall - October 4, 1985 to November 6, 1985
➢ Spring - March 3, 1986 to April 21, 1986
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➢ Summer - July 7, 1986 to September 7, 1986
Data gathered during these periods provided measurements of the low -flow season
(winter) and the maximum flow season (late summer). The first two sampling periods
also coincided with the startup and shutdown of the irrigation systems in the Yakima
Urban Area.
10.3.2.1 Summary of Infiltration from the 1985/1986 Evaluation
The 1985/1986 Infiltration and Inflow Evaluation provided evidence that significant
infiltration was present in the Yakima collection system. Variation in the groundwater
table was one of the methods used to gauge the amount of I/I in the system. A high
groundwater table is caused by irrigation from two sources: 1) application of irrigation
water at the ground surface; 2) leakage from the irrigation supply pipes and canals. The
effects on the Yakima sewer system due to irrigation startup and shutdown were quite
evident. At irrigation startup, treatment plant flows increased by 2.4 to 4.2 mgd within 3
to 5 days. With irrigation shutdown the decrease in flow ranged from 3.1 to 5.0 mgd,
which also occurred within 3 to 5 days. A major portion of the flow differences occurred
within five hours of irrigation startup or shutdown.
A larger difference in flows has been historically noted after irrigation system shutdown
than after its startup (except for 1986). When irrigation pipes or canals are filled, leakage
from them raises the watertable above the water level in the pipes and saturates the soil
before infiltration occurs. After irrigation shutdown, the watertable only has to drop to
the water level inside the pipes to slow infiltration. The change in watertable elevation
that produces a change in infiltration is greater for startup than for shutdown.
Much of the infiltration into the sewer system came from the General Irrigation System
and the Fruitvale Canal. There had not been evidence of any sudden increase in flows
due to the startup of any other irrigation system. Leaks from other irrigation systems and
from unlined canals do contribute to the groundwater rise, especially in the southeast
portion of the City.
The month of September was selected as a common base for comparison of flows from
the 1975, 1979 and 1985 to determine the effects of I/1 in the system. As shown on
Figure 10-2, the average daily flow (ADF) increased approximately 1 mgd between 1975
and 1979, and increased an additional 2 mgd between 1979 and 1985. Based on the
addition of approximately 13,000 people from 1975 to 1985 to the Yakima Regional
WWTP, the increase in flow should have been 1.1 mgd based on a residential sewage
flow of 80 gpcd, instead of the 3 mgd observed. A cause for this increase in extraneous
flows could be that the collection facilities deteriorated from 1975 to 1985. 1/1 flow from
the City of Union Gap and the Terrace Heights Service District is another possibility.
The I/I values estimated during the irrigation season for 1974, 1979, and 1986 totaled
12.9 mgd, 6.8 mgd and 9.9 mgd respectively. The 1/I estimate from 1974 was based on
the minimum daily flow being considered as entirety extraneous flow. It resulted in a
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CITY OF YAKIAMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 9
. _jure 10-2. Yakima Urban Area Comparisorb Recorded Flows from 1975, 1979 and 19b_
Sewage Flow (mgd)
24
20
16
12
8
4
0
_
September
12, 1985
/N.
N.�\
N
N
//
, /
/ /
September
September
17, 1975
6, 1979
1 1 1
1
1
1_
1
1
1
111
III
1
1
1
(am) (pm) (am) (pm)
Time
DRAFT
Targe estimate of infiltration since some sewage flow should have been expected at night.
The estimate of infiltration reported in 1979 was 75 percent of the reported minimum
daily flow. Extraneous flows were calculated at 68 percent of the minimum flow for the
1985/1986 data.
10.3.2.2 Summary of Inflow
In this evaluation of inflow to the City collection system, a regression analysis of average
daily rainfall versus the resulting increases in average daily flow at the Yakima Regional
WWTP was performed to measure the inflow into the system. Average daily rainfall
from 1997 to 1998 and 1974 to 1975 was used in developing regression equations to
estimate inflow. Calculated inflows for storm events from 1997 to 1998 and 1974 to
1975 are shown in Table 10-4 and compared with the estimated inflows from Figures 10-
3 and 10-4.
Table 10-4. Storm Inflows Comparison of Average Daily Flow
Increases with Predicted Flows for 1997-8 and 1974-5
Date of Rainfall Event
Rainfall (inches) Estimated Flow
Increase (mgd)1
Measured Flow
Increase (mgd)
April 25, 1974
May 17, 1974
August 18, 1975
August 27-28, 1975
December 30, 1996 - January 1, 1997
October 9, 1997
January 17, 1998
May 25, 1998
May 30, 1998
1.10
0.59
1.47
0.57
2.17
0.67
0.67
0.47
0.31
2.8
1.5
3.7
1.4
5.7
1.3
1.3
0.8
0.31
2.3
2.5
4.6
1.6
5.7
0.83
1.4
1.l
0.31
I. From inflow regression analyses of rainfall events over 0.30 inches from 1994 to 1998 and 1974 to 1975.
A correlation of the inflow recorded from the 1974 to 1975 and the 1997 to 1998
instantaneous flow increase is apparent. The measured flow increases from 1997 to 1998
are greater than those recorded from 1974 to 1975 for rainfall events greater than 1 inch,
as shown in Table 10-4. This increase was expected since the overall collection system
length has increased from 1974 to 1998. The instantaneous flow increases are highly
variable depending on rainfall patterns in the Yakima area, the antecedent moisture
conditions, and the flow routing times from the different parts of the sewer system.
10.3.3 Current Infiltration/Inflow Evaluation
The City of Yakima has continued to strive to remove more of the i/1 that flows into the
collection system. In the fall of 1990 the City began an aggressive 1/I reduction program.
Grouting the sewer lines has been the preferred approach for reduction of the infiltration
and inflow into the collection system. I/I removal activities from approximately 1990 to
1999 appear to have resulted in a flow reduction of over three million gallons per day
(3mgd) entering the Yakima Regional WWTP.
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PAGE I1
6
5.5
5
4.5
4
Ell - 3.5
3
0
= 3
a
0
cg 2.5
w
2
1.5
1
0.5
0
0
Figure 10-3. 1997 to 1998 Yakima Urban Area Average Daily Inflow versus
Rainfall
0.25 0.5 0.75 1 1.25 1.5
Rainfall (inches/day)
1.75
2
2.25
2.5
Estimated Inflow (mgd)
4
3.5
3
2.5
2
1.5
1
0.5
0
Figure 10-4. 1974 to 1975 Yakima Urban ,-,rea Average Daily Inflow Versus Rainfall
0
❑ Inflow Data
Regression Line
02
0.4
0.6
Rainfall (inches/day)
08
1
1.2
3
❑
u
❑
■
0
❑
0o
❑
-
Y=0.01
D
+ 2.53x
0
❑❑
0
❑ Inflow Data
Regression Line
02
0.4
0.6
Rainfall (inches/day)
08
1
1.2
DRAFT
As part of the facilities planning process for municipal wastewater treatment facilities, the
EPA requires that cities demonstrate that the sewage collection system is not subject to
excessive infiltration and inflow. The EPA has established criteria for determining
nonexcessive infiltration and inflow (40 CFR 35.2005(28)(29)) and has published a
guidance document on evaluating infiltration and inflow (I/I). The criteria are described
below. They are used to determine when the process of investigating I/I sources should
be initiated.
10.3.3.1 Nonexcessive Infiltration
Infiltration is considered to be nonexcessive if the average daily flow rate is less than 120
gallons per capita day (gpcd) during a dry period (7 to 14 days is suggested) when there is
seasonally high groundwater and no rainfall. Flow rates during this period should include
the maximum infiltration rate for the system when groundwater levels are high and inflow
is negligible. The 120 gpcd criteria has been established by the EPA from a survey of
municipalities around the country. It is the average of cities with typical domestic,
industrial, and commercial flows where the collection system is in good condition and not
subject to excessive groundwater infiltration.
10.3.3.2 Nonexcessive Inflow
The determination of whether inflow is nonexcessive is made using the highest daily flow
recorded during a storm event. If the total daily flow during high rainfall events is greater
than 275 gpcd, the EPA considers the system to have excessive inflow. This flow rate
includes infiltration and sanitary flows, as well as inflow of storm water. The EPA, using
a national average for systems in which all of the inflow sources that can be cost-
effectively removed have been eliminated, established this criterion.
10.3.3.3 Evaluation of Nonexcessive Infiltration and Inflow
Infiltration and inflow (I/1) were evaluated for the City of Yakima sewerage system by
examining the influent wastewater treatment plant data from the Yakima Regional
WWTP.
Infiltration into the Yakima collection system was analyzed by averaging influent
wastewater treatment plant flows from the summer, when the groundwater table is high
and there is little rainfall. Average daily flowrates for periods of the summer in 1997 and
1998 at times with no rainfall are shown in Table 10-5.
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Table 10-5. Yakima Urban Area Infiltration Evaluations
Dates Average Daily Flowrate Average Daily
(mgd) Flowrate (gpcd)
June 6 to 20, 1997 12.0 152.4
July 2 to 15, 1997 16.7 210.8
August 1 to 14, 1997 14.1 178.0
June 9 to 23, 1998 12.0 151.4
July 5 to 19, 1998 13.1 165.5
August 2 to 15, 1998 14.5 183.5
September 1 to 15, 1998 14.3 181.6
Total Average 13.8 174.7
1. From influent Yakima Regional WWTP wastewater flow data.
The total average daily flow rate of 13.8 mgd has been separated into components as
follows:
Flow Component Max. Mo. Average Flow Per Capita
Daily Flow
Residential Flow 7.2 mgd 80 gpd/capita
Commercial 1.1 mgd
Industrial 1.0 mgd
Institutional 0.2 mgd
Maximum Month Infiltration 4.3 mgd 48 gpd/capita
Total 13.8 mgd 128 gpd/capita
Based on a Service Area population of 90,000, the calculated per capita flow rate for non-
excessive average daily flow is 128 gpd/capita, which appears to exceed the EPA
screening criteria of l_21:111pd/capita. However, the infiltration component of 48
gpd/capita which is equivalent to approximately 480 gpad, generally conforms to the EPA
non -excessive criteria.
An estimated 5.7 mgd of inflow to the Yakima Regional WWTP resulted from 2.17
inches of rain from December 30, 1996 to January 1, 1997. The measured influent
wastewater flow increase from 7.91 mgd prior to the storm, to 13.56 mgd. At the current
Yakima Urban Service Area population of 90,000, this peak flowrate equals 150 gpcd,
well below the excessive inflow limit of 275 gpcd.
The City's current program of systematically identifying sources of I/1, and incorporating
rehabilitation of the collection system into the annual operations and maintenance
program, should be continued.
Separate wells owned by private parties in the City may be sources of inflow to the
sewage collection system. Private wells may provide supplemental water for washing
fruits and vegetables and for cooling or refrigeration processes which may find its way
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into the sanitary sewer system instead of into the storm sewer or food processing waste
systems.
Roof drains and area drains are another suspected source of inflow to the sewage
collection system. Direct connection of roof drains to the sewer system is suspected in
areas where storm sewers/subsurface drains are not readily available to property owners.
10.4 Maintenance Considerations
The sewage collection system is the only means of conveying wastewater to the Yakima
Regional WWTP. Interruptions in the collection system's service may result in a public
health hazard, considerable inconvenience, and of course, additional costs. Maintenance
goals generally center around keeping the system operational on a cost-effective basis.
The most cost-effective maintenance programs are those programs that stress preventative
maintenance.
The objective of a preventative maintenance program is to anticipate problem areas and
initiate action before any problems occur. Preventative maintenance assures good public
relations by protecting the public's sewer investment from deterioration. To be effective,
a preventative maintenance program should include:
➢ Effective tracking of the collection system.
➢ Cleaning and flushing on a scheduled basis.
➢ Treatment of roots that block the wastewater flow.
➢ Television inspection to visually determine the type of problems and trouble areas
in the collection system, and a grouting program to control a portion of the I/I.
> Rodding the collection system lines.
➢ Smoke testing to determine illegal connections and other sources of inflow.
> Measurement of flow and identification of sources of I/I.
> Spot excavation and repair.
> Keeping adequate records of preventative maintenance performed in critical
sections of the collection system.
➢ Safety.
Each of these areas is addressed in the discussions that follow:
10.4.1 Tracking the Collection System
The automated information maintenance management system (AIMMS) software
database has been used to track and inventory maintenance of the Yakima collection
system. AIMMS interfaces with a Geographic Information System (GIS) for managing
large amounts of information that is geographically referenced, tied, or related to, a
location. Geographic Information Systems include software for graphic processing,
database management, spatial analysis, and modeling. The City of Yakima GIS system
uses the City limits, the amended Urban Growth Boundary, and the Urban Reserve Area
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as boundaries. The GIS and AIMMS systems include information on collection system
hot spots, grouting locations, and other facility management information.
The AIMMS database can integrate both graphic and nongraphic data. It is capable of
printing out reports and work orders. With the AIMMS system, the City has been able to
determine the frequency of a problem in certain areas of the collection system and
schedule maintenance visits.
The City of Yakima has three classifications of collection system maintenance:
emergency calls, preventative maintenance (hot spots) and routine maintenance of the
lines, or other work orders. Emergency calls are dealt with on a case by case basis.
Preventative maintenance treats known problems typically caused by grease or roots.
Visits are scheduled regularly (i.e. annually, biannually) using the AIMMS system, to
clean or maintain the lines in an attempt to prevent future problems. Routine
maintenance is the maintenance of lines on a 5 -year interval. Record keeping consists of
indexing complaints, repairs, inspections, and rehabilitation measures.
The origin of hot spots in the collection system, whether it is grease, roots, ect. is
normally indicated by the AIMMS system. The original design or construction of the
lines has caused a percentage of these hot spots. For example, pipes with inconsistent
diameters can cause constrictions in the system. Twenty to twenty five work orders a
week are received by the City of Yakima Collection System Group for hot spots in the
system.
10.4.2 Cleaning and Flushing
A principal goal in earning public favor and maintaining system reliability is to insure
that sewers remain clear of stoppages and free of offensive air emissions. To attain this
goal, Yakima has developed a routine program of cleaning all gravity sewer lines using
the City's hydrocleaning equipment. The goal of the program is designed to dean all
sewers once every 5 years, but, due to limited equipment and personnel, this goal has not
been achieved.
The City of Yakima's hydrocleaners are capable of cleaning 500 to 700 feet of collection
system line per set-up. This length can be shortened by turns in the line. The large size of
the hydrocleaners limits their access to backyards. Depending on the size, slope, and
condition of the line to be cleaned, a crew can routinely clean from 500 to 2,000 feet per
day with an average of approximately 1,500 feet cleaned per day. In addition to cleaning
and flushing with hydrocleaning equipment, the City mechanically cleans sections of the
sewer that cannot be accessed by the hydrocleaners.
10.4.3 Treatment of Roots
A significant portion of the City's existing collection system was constructed prior to the
advancement of pipeline construction using the rubber ring joint. Roots typically enter
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the lines at the top of joints in the pipeline where mortar or mastic has crumbled or
become dislodged due to age or other conditions. Side laterals (private building sewers)
are also a source of root entry to the City's lines. Upon entering the sewer the roots
expand and branch out, hanging in large masses into the flow, accumulating grease and
debris, which may result in blockages.
The City of Yakima has historically used both mechanical and chemical application by
surface contact to destroy root masses. Both of these techniques provide temporary relief
from the problems associated with root growth, but neither has proven to an effective
long-term solution. Mechanical removal may actually stimulate regrowth, resulting in the
need for more frequent maintenance.
The most cost-effective root control program is to use proper installation techniques,
which produce tight construction joints. The improved configuration of a pipeline joint
from an unsealed contact between pipe segments to a carefully designed rubber ring
gasket between the spigot and bell has helped to control root problems.
The City of Yakima has recently used the Duke and Rootex companies to alleviate root
problems in the collection system. Extreme care must be used when applying chemicals
to the sewer system to avoid injury to the workers and damage to adjacent buildings.
Problems with toxicity at the wastewater treatment plant has been associated with the use
of Duke products in the past when for a one day period the ammonia level rose above the
maximum allowable permit concentration at the Yakima Regional WWTP. These
chemicals were used on approximately 10,000 feet of collection system line in 1998-
1999.
10.4.4 Grease Removal
Grease deposits in the collection system result in significant preventative maintenance
activities by the City staff. Although grease traps have been installed in many of the
commercial and institutional facilities in the community, the current installations and
maintenance of the installations may not be adequate. Failure of the current grease trap
installations may be associated with requirements for high temperature water during
operation of the automatic dishwashers located at these facilities, and an infrequent
cleaning schedule. For the City's grease control to be effective, the property owner's
cooperation, and an adequate collection and disposal system for the grease must be
included.
A grease interceptor is necessary where grease, fats, oils, or similar line clogging
contaminants are present in the sewage. Typical locations for grease traps include
restaurants, cafeterias, hotels, schools, hospitals, institutional or commercial buildings
having facilities for the preparation and serving of food, commercial food processing
plants, dairies, and other industries where grease and fats are a by-product.
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Sizing of the grease trap is one of the first considerations to help resolve a grease
problem. Typically, sizing is based on the capacity of the fixture being served by the
grease trap unit. Dishwashers normally require a separate grease interceptor from other
fixtures. When high temperature water is used (usually about 140 degrees Fahrenheit) the
grease trap can either be oversized (doubled at minimum) or cooling water can be added
to the waste prior to entering the grease trap (approximate equal volume).
A second potential solution to the grease problem is to require more frequent cleaning.
The period at which grease is removed can vary from more often than once a week to less
than once a month. When frequent removal is required, automatic draw -off grease traps
should be used. By providing simple, fast, and easily accomplished cleaning, personnel
will be more likely to follow a regular cleaning schedule. Physical removal may be time
consuming and messy, resulting in a complete lack of maintenance. The local handling
service should place the accumulation of grease and water from the automatic draw -off
systems, or from the physical removal, in a sealed container for pickup. Rendering
companies specializing in the handling and reuse of fats and grease should be consulted
to help develop a handling and disposal plan which is both simple and efficient.
Minimum inconvenience for the customer, the handler (grease recycler), and the
rendering facilities staff will assure the success of a grease separation program.
Currently, the City of Yakima has pretreatment requirements for grease and has been
working with the City crews and commercial businesses to reduce the amount of grease in
the collection system. This pretreatment program has not alleviated all the grease
problems in the City of Yakima, but further monitoring and enforcement should help to
ensure its success.
The City of Yakima has recently began discussions with the Yakima Health District and
Yakima County Solid Waste regarding the management of the current grease reduction
program. Grease traps and grease dumpsters are the Health District's responsibility for
monitoring. The City and Health District should define their individual roles in order to
reduce grease problems and insure that duplicate work does not take place.
In addition to grease interceptors, the City should require the installation and operation of
oil interceptors. An oil interceptor should be required where lubricating oil, cutting oil,
kerosene, gasoline, naphtha, paraffin, trisodium phosphate, and other light density and
volatile liquids are present in the sewage system. Typical locations for an installation
include service stations, garages, auto and truck repair shops, dry cleaners, laundries,
industrial plants, or process industries having machine shops, metal treating process
rooms, chemical process or mixing rooms, ect.
The separated oils and other light density volatile liquids would be drawn -off
automatically from the interceptor to a separate storage tank so they can be operated
continuously. A system of collection and disposal must be in place before a program of
oil separation can be effective.
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A third type of interceptor available is the solids trap which may have some practical
applications in Yakima on industrial discharges to the sanitary sewers. Solids
interceptors remove such undesirable particles as sand, metal fillings, glass, or other
settleable solids.
10.4.5 Television Inspection and Grouting Program
Inspection by closed circuit television is by far the most effective method of ascertaining
the nature of internal collection system problems. The City purchased it's initial
television equipment in the mid -1970's. Currently, all new construction is inspected, by
the City of Yakima, prior to acceptance of the construction contract, deficiencies are
recorded, and corrections are made.
The TV crew is the first to inspect new collection system lines. Their function is to
confirm the location and condition of the collection system and number the manholes.
The map prepared by the TV crew in turn goes to the GIS department where the manhole
numbers are confirmed and the pipes are given an AIMMS number. Copies of the
revised maps are distributed to all wastewater map holders on a periodic basis.
Television inspection is also utilized by the City in the identification of the types of
system problems and existing system features.
The City of Yakima currently owns a TV/grouter unit, purchased in 1990. This unit has
an expected useful life of 5 to 7 years. Grouting operations are typically performed from
April through October, due to area temperatures. Grouting should be performed after the
TV crew has inspected the line, but this has not always been the case due to work
priorities. Additional procedures to improve the coordination of TV/grout crew should be
developed.
Approximately 6,000 to 8,000 feet per year of grouting in the collection system is
performed on average due to crew availability, weather, and location. A crew is capable
of grouting approximately 350 to 700 feet per day. At a rate of 7,500 feet per year, it
would take approximately 200 years before the collection system has been televised,
inspected, pressure tested, and grouted if necessary. Grouting normally lasts from 5 to
10 years.
The collection system line grouting priorities identified in the 1988 Comprehensive Plan
have been completed. These sealing and grouting activities have removed approximately
3 mgd of extraneous water flow from the facilities peak month flow. At an estimated
$3.50 per gallon construction cost for secondary facilities, this translates into a savings of
approximately $10.5 million in construction cost.
10.4.6 Rodding Techniques
Collection system rodding has been performed to clean collection system sewer lines and
clear obstructions. Rodding the collection system line is performed one section at a time.
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The typical time to rod a section of line is one to three hours from setup to completion. If
the line must be sliced, or access to manholes is difficult (located in backyards, covered
with landscape, buried in gravel roads or alleys or on private property), additional time is
required to perform this task.
10.4.7 Smoke Testing
Smoke testing can be used to determine problem areas prior to physical or television
inspection. Sources of observed smoke around individual structures, catch basins, surface
areas, ect., are located and recorded, providing the basis for further.examination and/or
corrective actions. The City has also used smoke testing equipment to reveal illegal
connections to the sanitary sewers, including roof drains and cross connections with
storm drain facilities. The smoke tests are weather dependent and are difficult to perform
under cloudy, rainy, or windy conditions that make source identification difficult. Crew
availability determines the frequency of these tests.
The City of Yakima has recently purchased new smoke testing equipment. This
equipment has proven to be effective in continuing to locate undocumented connections
to the collection system that have not been previously billed.
10.4.8 Measurement of Flow and Identification of I/1
Prior to the 1988 Comprehensive Plan, the only flow measurements conducted by the
City of Yakima on a continuous basis were those made at the Yakima Regional WWTP
and the Rudkin Road Pumping Station. Flow monitoring conducted for the 1988
Comprehensive Plan was effective in identifying the location and quantity of I/1 in the
system. This effort should be continued for several reasons:
➢ Prior to actual design and implementation of improvements, additional
measurements should be made to better define the magnitude and frequency of the
I/I peaks. This will allow more accurate and economical sizing of facilities.
➢ Flow measurements are necessary for assessing the benefit derived from the
rehabilitation work performed.
➢ Routine flow monitoring will allow the City of Yakima to detect signs of future
deterioration in the collection system or new sources of significant I/1 flows.
A comprehensive flow monitoring program is recommended to be implemented by the
City of Yakima. This comprehensive program will establish current drainage basin flow
characteristics that can be utilized as a point of reference for future annual monitoring by
the City staff. The system flows can also be used to verify the hydraulic model of the
collection system. The monitoring periods to be included in the program would be: 1)
prior to irrigation system startup; 2) high season flows, and; 3) at shut -down of the
irrigation systems.
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10.4.9 Spot Excavation and Repair
The objective of spot excavation and repair is to determine the location of problem areas
in a length of line, excavate the overburden from the line, and remove and replace the
damaged areas. Excavation and replacement of defective pipe segments is normally
undertaken when the structural integrity of the pipe has deteriorated so severely that
alternative rehabilitation techniques are not feasible. The maintenance staff typically
contracts with private companies to complete spot repairs including replacement of
collapsed or broken pipes that can be accomplished with limited excavations.
The maintenance crew and private companies have also performed minor repairs required
at manholes within the system. A manhole rehabilitation program was begun in 1998
with an annual goal of sealing 10 to 15 manholes with a cementations coating. A private
contractor did the work in 1998 at a cost of $90 per foot of height. The effectiveness of
this program was confirmed by the maintenance crew during the 1999 irrigation season
when the groundwater levels were high. In 1999, the cost per foot of height had risen to
$120.
10.4.10 Safety Concerns
The dangers associated with collection system operation substantiate the need for safety
practices. Physical injuries and infections are a continuous threat. Explosions and
asphyxiations have occurred during sanitary sewer and pumping station maintenance in
other communities. The City of Yakima has a safety program in place using both safety
practices and safety equipment. Safety issues that are involved in the maintenance of the
Yakima collection system include:
➢ Manhole Entry
• In the event that a crew has need to enter a manhole, the City of Yakima
follows confined space entry requirements. This includes a safety harness,
tripod, gas meter, and winch that are provided by the City of Yakima.
➢ Flagging
• When manholes are located in the roadway, traffic control/flagging is used.
This will normally take two crews (1 working crew, with another crew
flagging). Sewer lines are now being constructed in the center of a lane of
traffic instead of the middle of the road in order to enable the crew to close
only one lane.
➢ Pathogen Safety Training
• Completed by all of the crew members.
➢ Safety Manual
• The City of Yakima has written a safety manual that covers the safety
standards for the City of Yakima.
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10.4.11 Yards and Shops
A centrally located shop has been provided for the wastewater collection and surface
drainage collection service units. Yards and shops are the basis from which all work
starts, and should be self-sufficient and independent. Central supplies and materials for
heavy-duty repairs are incorporated into the common facility for all utility service units.
The current centrally located shop is approaching its capacity. Vehicle parking and
equipment storage spaces at the centrally located shop are currently at capacity. The
locker room is also nearing capacity, with 3 or 4 empty lockers remaining. The
maintenance facility will need to be expanded to accommodate future staffing and
equipment needs.
10.4.12 Equipment
Many items of specialized equipment are used in the maintenance of sanitary and storm
sewers. The City of Yakima appears to have sufficient equipment currently available for
the level of staffing in the wastewater collection system. An aggressive inflow program,
rehabilitation program, and storm drainage program will require additional equipment and
staffing.
10.5 Organizational Structure
The Yakima Sewerage Division operates under the direction of the Wastewater Division
Manager. The City Manager has the ultimate responsibility for the utility and provides
guidance to the Wastewater Division Manager.
The sewer utility division has been separated into six service units: 1) wastewater
collection (Service Unit 211); 2) surface drainage collection (Service Unit 213); 3)
Rudkin Road pumping station (Service Unit 215); 4) wastewater treatment (Service Unit
232); 5) pretreatment (Service Unit 233) and 6) food processing wastewater (Service
Unit 234).
The wastewater collection service unit is responsible for the operation and maintenance
of all lift stations, and publicly owned sanitary sewer pipelines within the City of Yakima
sewage collection system. In addition to those lines within the City limits, the wastewater
collection service unit operates and maintains those sewers within the unincorporated
areas adjacent to the City. The collection systems within the City of Union Gap and the
Terrace Heights Sewer District are separately operated and maintained by those agencies.
A total of 290 miles of pipe and 9 lift stations are operated and maintained by the
wastewater collection service unit within the Yakima Urban Area.
The surface drainage collection service unit is charged with operating and maintaining the
storm sewer/subsurface drainage system within the City of Yakima. A total of 278 miles
of pipelines, canals, and ditches are included in the storm sewer/subsurface drainage
system.
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The wastewater collection and surface drainage collection service units have a combined
staff of 14 maintenance employees and a sewer maintenance supervisor.
The current population in the area served by the Yakima wastewater collection and
surface drainage unit, including the City of Yakima and adjacent unincorporated areas,
was estimated at approximately 78,987 in the Yakima Urban Area Comprehensive Plan.
As a point of comparison, Table 10-6 presents a typical staff complement for wastewater
and surface drainage collection systems serving various sized communities. Examining
this table indicates that Yakima should have a total of 28 to 30 maintenance personnel in
the wastewater collection and surface drainage unit based on similar sized communities.
As the State and Federal governments adopt new regulations, as the population and the
service area increases, and as responsibilities of the wastewater collection and surface
drainage collection units are increased, the staff needs required to maintain the current
high level of operation and maintenance should be reviewed. The Wastewater Division
Manager will address manpower needs during the City's annual budgeting process.
Table 10-6. Typical Staff Compliments for Wastewater Collection Systems
Occupational Title Population Size2
5,000 10,000 25,000 50,000 100,000 150,000
Superintendent 1 5 1 10 1 20 1 40 1 40 1 40
Asst. Superintendent 1 40
Main. Supervisor 1 40 2 80 2 80
Foreman 1 15 1 20 1 20 1 40 1 40 2 80
Maintenance Man II 1 15 1 20 1 20 1 40 1 40 2 80
Maintenance Man 1 1 20 2 60 3 120 5 200 8 320
Mason II 1 40 1 40 2 80
Mason I 1 15 1 40 1 40
Main. Equip. Operator 1 40 2 80 - 3 120 5 200
Constr. Equip. Operator I 15 1 20 1 20 1 40 1 40 2 80
Auto Equip. Operator I 40 1 40
Photo Inspection Technician 1 40 I 40
Laborer 1 15 1 20 2 40 2 80 5 200 6 240
Dispatcher 1 40 2 80 2 80
Clerk Typist 1 20 1 20 2 80
Stock Clerk 1 40 1 40 I 40
Sewer Maintenance Staff 6 80 6 110 9 220 16 620 27 1060 39 1560
Maintenance Mechanic II3
Maintenance Mechanic 14
Maintenance Mechanic Helpers
Construction Inspector6
Construction Inspector Supv.7
1. Presented in the Water Pollution Control Federation Manual of Practice No. 7 — Operation and Maintenance of
Wastewater Collection Systems.
2. For each population size, the number of personnel and estimated total man-hours per week is provided.
3. To approximate the number of hours needed, multiply the number of pumping stations maintained by 2.67.
4. To approximate the number of hours needed, multiply the number of pumping station visits per week by 2.67.
5. To approximate the number of hours needed, multiply the number of pumping stations maintained by 2.67.
6. To approximate the number of hours needed, multiply the estimated construction site visits by 2.67.
7. Determined by the number of construction inspectors employed and developed on a judgmental basis.
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10.6 Staffing Requirements
This report will review the requirements for a preventative maintenance program to
establish staff requirements specifically for the Yakima Urban Area. These requirements
will provide an estimate of the staffing needs in the existing wastewater and surface
drainage collection system to compare with Table 10-6 and are discussed below.
10.6.1 Collection System Tracking
Tracking the collection system is performed by the City of Yakima.GIS and A1MMS
personnel. These employees update the database with the known problem areas and new
construction projects involving the Yakima sewer system and surface drainage system.
They also determine the schedule for routine cleaning of the collection system as well as
the more involved rehabilitation projects. A total 832 man-hours (2 days/week) of
technical assistance is required for maintaining the wastewater collection and surface
drainage collection system database.
Record keeping for the wastewater collection and surface drainage unit consists of
indexing complaints, repairs, inspections, and rehabilitation measures. The City's data
logging programs offer a convenient method of recording historical data and scheduling
preventative maintenance items. They provide an effective tool for cataloging
information obtained from review of the television inspection tapes. A record keeper
working approximately 2 days per week should be capable of performing these tasks (104
man -days or 832 hours).
10.6.2 Cleaning and Flushing
A program to clean sewer lines every 5 years is a goal that has been used by the City of
Yakima in the past (58 miles per year). Problem areas are cleaned more frequently until
system repairs are made to eliminate the restrictions. The City currently has about
300,000 linear feet of pipeline that must be cleaned annually. A total of 1,600 crew hours
(4,800 man-hours) would be required annually to clean the sewers on a 5 year cycle (1
crew, 200 days, 1,2001f/day). In order to clean the hotspots in the collection system an
additional 2000 crew hours (6000 man-hours) would be required annually (1 crew, 250
days).
At the present time, the surface drainage collection system is maintained on an emergency
basis only. Adoption and implementation of a Storm Water Utility will add a
preventative maintenance program for cleaning and flushing of the surface drainage
collection system and drainage ways. With approximately 290 miles of pipelines and
drainage ways and adoption of a program to clean the system every 10 years (29 miles per
year), a total of 1,232 crew hours (3,696 man-hours) would be required (1 crew, 154 days,
1000 if/day).
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10.6.3 Treatment of Roots
The City has historically used both mechanical cleaning and chemical application
techniques for root removal. Recently, chemical application has been chosen as the
future method of root removal. Proper application of the appropriate chemicals will
provide the collection system with a 3 to 5 year cycle of root removal.
Based on a 5 year cycle of root removal for 50,000 if of pipelines, a total of 120 crew
hours (360 man-hours) would be required annually to effectively manage the current root
intrusion problems in Yakima (1 crew, 15 days, 7001f/day). Without permanent
correction of system problems that result in root intrusion, the level of staffing required
will increase in the future.
10.6.4 Grease Removal
The City of Yakima's cleaning and flushing program includes the removal of grease from
the collection system. The implementation and enforcement of the sediment trap/grease
program would be part of a community wide Pretreatment Program. The manpower for
this program would be included in the Pretreatment Program.
10.6.5 Television Inspection
Inspection by closed circuit television is the most effective method of determining the
nature and extent of internal problems in the City's collection system. In addition, an
updated television inspection of the entire system would provide an inventory of all
system conditions that could be used to prioritize rehabilitation options for the City
system. Currently, television inspection is used on new sewer lines, for locating stubs,
laterals, and inspecting existing lines with problems.
A program to internally inspect the system every 10 years should be considered by the
City of Yakima. If the City were to implement this program, a total of 1280 crew hours
(3,840 man-hours) would be required annually (1 crew, 160 days, 10001f/day).
To provide for television inspection of new sewer lines, identification and verification of
sewer stub locations, and for emergency response for inspection of existing sewer lines, a
total of 640 crew hours (1,920 man-hours) would be required annually (1 crew, 80 days,
500 if/day).
Television inspection of the surface drainage collection system should also be undertaken
upon adoption and implementation of a Storm Water Utility. A program to internally
inspect 100,000 linear feet of storm drainage piping would require 800 crew hours or
2400 man-hours (1 crew, 100 days, 10001f/day).
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10.6.6 Grouting Program
Grouting the sewer lines in the Yakima collection system has been the most effective
method of sealing the sewers and reducing infiltration. The grout has an approximate life
of 6 to 10 years. If a sewer system grouting program for the entire system was needed
every 10 years, the City of Yakima would require a total of 2,400 crew hours (7,200 man-
hours) annually (2 crews, 150 days, 5001f/day). A site specific grouting program is
recommended for the Yakima collection system where 1 crew will work full time
grouting the most problematic collection system lines (1 crew, 210 days, 300 if/day), or
1,680 crew hours or 5,040 man-hours (63,000 feet per year).
10.6.7 Smoke Testing
Smoke testing has historically provided a less complex method of determining some of
the problem areas and illegal connections to the collection system. For this study, it is
anticipated that during a three month period (in the summer months) and also during the
winter as weather permits, a crew comprised of a supervisor and three student assistants
would perform smoke testing full time. This would result in approximately 240 crew
hours (1,920 man-hours) annually (1 crew, 60 days).
10.6.8 Spot Excavation and Repair
Spot repairs to the collection system are performed on an as needed basis. Based on these
types of repairs taking one crew approximately 8 hours per week to complete, 416 crew
hours (1,250 man-hours) would be spent per year (1 crew, 52 days).
Spot repairs of the surface drainage collection system will also be required. An additional
1,250 man-hours (416 crew hours, 1 crew, 52 days) will be required upon adoption and
implementation of a Storm Water Utility.
10.6.9 Safety Concerns
The dangers associated with collection system operation substantiate the need for safety
practices. Physical injuries and infections are a continuous threat.
An ongoing safety program requires a minimum of 40 hours of training per employee
annually. Monthly meetings of the operations staff for a minimum 2 -hour period each
month are recommended. In addition, special training programs are offered on a
statewide basis for collection system personnel, and each City employee should be
required to attend.
During utility operations in roadways, traffic control is required including traffic flagging.
On local residential streets, traffic control generally consists of placement of traffic cones.
When flagging is needed, a second operations crew is required to perform flagging
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responsibilities. A total of 320 crew hours (2,560 man-hours or 40 days) are anticipated
to be required annually.
10.6.10 Yards and Shops
In addition to the above specific preventative maintenance operations, several other
activities are generally required by the collection system staff to assure the overall cost-
effectiveness of the program.
Properly organized yard and shop facilities are needed for the collection system
operations. Central supplies and materials need to be available for the sewer collection
service unit to function. Routine grounds up -keep, light bulb replacement, lubrication of
doorways and hatches, and painting and coating are needed services. A total of
approximately 16 man-hours per week or 832 annual man-hours are required to organize
and prepare for the sewer collection and surface drainage service unit operations.
For maintenance of collection system equipment, the City can utilize the public works
maintenance facilities for routine servicing. A total of 8 man-hours per week or 416
annual man-hours are required for equipment services not readily available through the
public works facilities.
10.6.11 Lift Station Equipment
Each lift station should be visited at least three times per week with one visit including a
complete cleaning (wash -down) and lubrication of the facility. Electrical equipment
should be tested once per week to confirm operating conditions. Maintenance programs
for lift stations include periodic measurements on all pumps, motors, motor control
centers; and electrical connections. Based on 6 crew hours per lift station per week, a
total of 624 man-hours per lift station per year, or 3,744 total man-hours (9 lift stations)
are needed.
10.6.12 Collection System Summary
Table 10-7 summarizes the man-hours required for implementation of a preventative
maintenance program for the sewer collection and surface drainage service unit in the
City of Yakima.
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Table 10-7. City of Yakima Wastewater Collection Manpower Summary
Task 1998 Annual Requirements
(man-hours)
Collection System Tracking 8321
Record keeping 832
Cleaning and Flushing (Sewer) 10,8002
Cleaning and Flushing (Drainage) -5
Treatment of Roots 360
Television Inspection (Sewer) 5,760
Television Inspection (Drainage) s
Grouting Program 5,040
Smoke Testing 1,920
Spot Excavation and Repair (Sewer) 1,250
Spot Excavation and Repair (Drainage) -5
Safety Concerns 3,5204
Yards and Shops 1,248
Lift Station Equipment 3,744
Total 35,306
1. 832 hours performed by the City of Yakima staff.
2. Includes 4,800 man-hours for preventative cleaning and 6,000 man-hours for cleaning of "hot -spots".
3. Removal of grease included in the man-hours for collection system cleaning and flushing.
4. Each of the current 15 employees requires 40 hours of annual training plus 24 hours for monthly meetings plus
traffic control (2,560 hours).
5. Shown elsewhere.
With an expected utilization of 1660 hours per employee annually, the City would need a
minimum of 20 people plus a supervisor to fully staff a preventative maintenance
program for the existing sewer collection system, or an increase of 6 full time staff over
current levels to meet present needs. This staffing requirement is less than the level
identified in Table 10-6. This variance may be attributed to certain characteristics of the
sample communities that were evaluated in the development of Table 10-6 including
multiple responsibilities (sewer collection and storm drainage, routine maintenance of
equipment), extensive system repairs (major and minor repairs, extensive rehabilitation
program), or system configuration (remote areas, terrain, etc.).
With no increase in the current staffing levels, budgeted operating expenses for the
collection system of $1,706,507 are projected to increase by about 4.7 percent per year,
reaching $1,958,853 in 2001, as shown in Table 10-8. Collection system expenses
currently represent approximately 30.07 percent of the operating expenses of the
sewerage system. The Utility Fees line item includes capital and debt service expenses
for the collection system's share of the outstanding 1978 revenue bonds, transfers to
capital budgets, debt service payments for collection system construction projects,
residual equity payments on new vehicles, and the collection system's portion of two
street construction projects.
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CITY OF YAKIMA
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Table 10-8. City of Yakima Collection System Expenses
Description
Staff Costs
Operating Supplies, Maintenance
Machinery and Equipment;
City Services/Ancillary Costs4
Total
Estimated 1998
$871,832
$114.124
$205,923
$494,628
$1,686,507
Estimated 1999
$912,044
$119,830
$216,219
$518,611
$1,766,704
Estimated 2000
$954,113
$125,822
$227,030
$543,790
$1,850,755
Estimated 2001
$998,128
$132.114
$238,381
$570,230
$1,938,853
1. Includes salaries and wages, and personnel benefits.
2. Includes office/operating supplies, fuel consumed, resale/small tools, chemicals, professional services (money for
implementation of modest repair programs of existing facilities), communications, transportation/training.
advertising, operating rentals/leases, public utility services, repairs and maintenance, and miscellaneous expenses.
3. Includes machinery and equipment, and interfund rentals/leases.
4. City services, administrative overheads, state and local fees, and other charges.
With an expanded and fully staffed preventative maintenance program, as set forth in this
Section, the annual costs of the wastewater collection service unit will be increased.
Table 10-9 identifies the proposed budgeted operating expenses with a suggested 3 -year
implementation schedule beginning in 2002.
Table 10-9. City of Yakima Proposed Collection System Expenses
Description
Estimated 20011
Estimated 2002
Estimated 2003
Estimated 2004
Staff Costs
$1,115,950
$1,275,0002
$1,425,0002
$1,575,0002
Operating Supplies,
Maintenance
$195,546
$223,000
$249,000
$276,000
Machinery, and Equipment
$293,363
$338,000
$378,000
$418,000
City Services/Ancillary Costs
$600,570
$688,000
$770,000
$851,000
Total
$2,205,429
$2,524,000
$2,822,000
$3,120,000
From Table 10-8 and 10-10.
22 FTEs added 2002, 21^ 1'hs added 2003, 2 FTEs added 2004.
10.7 Existing Stormwater Program
The wastewater utility is currently delegated the responsibility of operating and
maintaining the City's storm sewer system. Storm drainage does not currently have any
dedicated unique funding source and costs associated with this activity are included in
rates assessed to City of Yakima retail sewer system customers. Budgeted operating
expenses for the storm sewers of $198,662 are projected to increase by about 10 percent
per year, reaching $266,576 in 2001, as shown in Table 10-10. These increasing
expenses anticipate mandated increases in activity related to Storm Water during the
planning period. They represent about 3.5 percent of the total current operating expenses
of the sewer system.
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Table 10-10. City of Yakima Storm Drainage Expenses
Description
Staff Costs'
Operating Supplies, Maintenance2
Machinery and Equipment3
City Services/Ancillary Costs
Total
Estimated 1998
$77,470
$58,830
536,151
$20,211
$198,662
Estimated 1999
$89,090
560,157
$41,574
$27,519
$218,340
Estimated 2000
$102,453
561,681
$47,810
$28,895
$240,840
Estimated 2001
$117,822
$63,432
554,982
$30.340
$266,576
1. includes salaries and wages, and personnel benefits. Approximately $75,000 per FTE in 2001.
2. Includes office/operating supplies, fuel consumed, professional services (money for implementation of modest
repair programs of existing facilities), communications, transportation/training, advertising, operating
rentals/leases, public utility services, repairs and maintenance, and miscellaneous expenses.
3. Includes machinery and equipment, and interfund rentals/leases.
The 1993 Comprehensive Storm Water Management Plan and the EPA Phase 2 Storm
Water Regulations will have an effect on the future of the stormwater program for the
City of Yakima and surrounding areas. The regulation will require changes to City
ordinances to allow stormwater inspections, and monitoring of industrial, commercial,
domestic, and construction dischargers. It will also necessitate cooperation with other
public agencies up and down the river. A significant change will be that stormwater
permits will be issued by the WDOE office in Lacey, not the Central Region office
located in Yakima. The City staff has a good working relationship with the local WDOE
staff. Not only will City staff have to work with a different group of WDOE officials for
the Wastewater Facility NPDES permit and the City's General and Industrial stormwater
permits, but also making WDOE officials from Lacey aware of conditions unique to
Yakima will be time consuming.
10.8 EPA Phase II Storm Water Regulations
EPA's Phase 11 Storm Water Regulations will require the City of Yakima (and Yakima
County) to establish a storm water management program that would reduce the quantity
of pollutants that storm water picks up and carries into storm water systems to the
"maximum extent possible (MEP)" during storm events. Common pollutants which are
of concern include oil and grease from roadways and parking areas, pesticides and
fertilizers from lawns, sediment from construction sites, animal feces from grassed areas,
detergents from community car washing events, and carelessly discarded trash such as
cigarette butts, paper products, and plastics. If these pollutants are discharged to
waterways, they can impair surface water which may impact recreational use, contaminate
drinking water supplies, and interfere with habitat for aquatic life and other wildlife. If
these pollutants are discharged to dry -wells, they may impair groundwater which could
impact the use of the groundwater as a potential source of a drinking water supply, or as a
supplemental source of surface water flow.
The EPA Phase 11 Storm Water Regulations are developed around the implementation of
approved "best management practices (BMP's)" which are considered to comply with the
technical standard of MEP. There are six (6) required program elements that are expected
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to result in significant reduction of pollutants discharged in storm water. The six program
elements are considered to be "minimum control measures" and are described as follows:
➢ public education and outreach
D public involvement and participation
D illicit discharge detection and elimination
D construction site storm water runoff control
D post -construction storm water management
D pollution prevention, or "good housekeeping" for municipal oeprations
The following provides a brief description of the "minimum control measures (MCM)"
and includes a discussion as to how the measures will impact Yakima.
D Public Education and Outreach. Distributing educational materials and
performing outreach to inform citizens about the impacts polluted storm water
runoff discharges can have on water quality.
Yakima Impacts. This MCM is likely an extension of activities that the City
currently has underway. A public relations specialist would be responsible for:
• Distribution of water quality information relating to the impacts of stormwater
(mail -outs and handouts). There is a lot of this information available about
over -watering, fertilization, animal feces, pesticides, dumping oil into storm
sewers, etc. that can be used.
• Making presentations at schools in the area which can include material
handouts and likely some visual graphics that present the "water cycle".
• Making presentations to community groups. Likely the same handouts and
graphics as for the schools.
• Making presentations to the homebuilders, industrial groups, neighborhood
groups, or basically anyone that will listen. Again the same handouts and
graphics.
• Organization of volunteer groups to perform community projects relating to
water quality such as: distributing pamphlets door-to-door; stenciling catch
basins; cleaning up drainage ditches; cleaning along creeks/rivers;
neighborhood cleanup projects (leaves, animal feces, etc); planting trees along
creeks/rivers;
For the first 3 to 5 years, the level of involvement of the public relations specialist
for storm water would be at least full-time. Even after the 5 -year period, the
minimum level of involvement would be at least 3/4 time. For purposes of this
discussion, one full-time public relations specialist would be required and would
be one of the first employees hired.
> Public Participation/Involvement. Providing opportunities for citizens to
participate in program development and implementation, including effectively
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publicizing public hearings and/or encouraging citizen representatives on a storm
water management panel.
Yakima Impacts. The requirements for this MCM have been included in the
citizen participation/involvement MCM in the discussion above. Other items
included here would be to develop articles that could be published in the
newspaper on community activities, and preparation of public notices. The
citizen representation issue is addressed through the volunteer groups.
These activities would not increase staffing above the full-time public relations
specialist identified previously.
Illicit Discharge Detection and Elimination. Developing and implementing a
plan to detect and eliminate illicit discharges to the storm sewer system (includes
developing a system map and informing the community about hazards associated
with illegal discharges and improper disposal of waste).
Yakima Impacts. This MCM requires field investigation, sampling, and testing.
It would be possible to utilize community volunteers to some extent, but the
likelihood is that the City would need to staff this program. Illicit discharges can
generally be identified as waste flows from residential, commercial, and/or
industrial sources that should be discharged to the sanitary sewer instead of the
storm sewer. These could include cooling water that comes into contact with a
contaminate; hard surfaced areas where products are stored that are purposely
washed -off, or are washed -off as the result of storm events to a storm drain; local
community car wash events where the wash water flows to a storm sewer/drain; a
sanitary sewer interconnected accidentally to the storm sewer/drain; and a host of
individual property owner activities such as washing their vehicle in their
driveway, excessive lawn watering, discharge of sump drains, etc.
This activity will require two full-time positions responsible for investigation and
sampling, and working with community volunteers on investigations. The
sampling means testing and would likely add a'/2 time laboratory technician.
➢ Construction Site Runoff Control. Developing, implementing, and enforcing an
erosion and sediment control program for construction activities that disturb 1 or
more acres of land (controls could include silt fences and temporary storm water
detention ponds).
Yakima Impacts. This is probably one of the more controversial MCM's in that
it requires the construction industry to comply with added provisions. The City
will need to adopt a menu of standards that apply to construction sites. The
WDOE's proposed approach far exceeds the intent of the EPA Phase II Storm
Water Regulations, and would require increased staffing for implementation of
this MCM.
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CITY OF YAKIMA
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The menu of Construction Site Runoff Control would be adopted as Design
Standards. Both the "Drainage Criteria and Design Manual" by HDR in 1994,
and the WDOE "Stormwater Management Manual" could be used as resource
documents in developing a simplified menu of standards to be applied for
Yakima.
The menu would be developed in cooperation with the construction industry
rather than applied as a mandated government regulation. This cooperative effort
would also be supportive of the "Public Participation/Involvement" MCM
described previously.
This MCM also requires a permitting and inspection process to ensure
compliance, and of course, implementation of penalties for non-compliance. The
review and permitting requirements could be incorporated with other plan review
responsibilities currently performed by the City. The review and permitting will
likely require the dedication of a }/ time person. The field inspection activities
could also likely be incorporated into on-site building or site inspection
responsibilities of existing staff. Increased responsibilities are likely to add the
equivalent of a } time person. Finally, the enforcement responsibilities will likely
require notifications, consent orders, penalty orders, publication in local
newspaper, etc. This activity is also anticipated to result in a'/2 time person.
Post -Construction Runoff Control. Developing, implementing, and enforcing a
program to address discharges of post -construction storm water runoff from new
development and redevelopment areas. Applicable controls could include
preventative actions such as protecting sensitive areas (e.g., wetlands) or the use
of structural BMPs such as grassed swales or porous pavement.
Yakima Impacts. This MCM can be developed in a much simpler format than
currently proposed by WDOE. The "Drainage Criteria and Design Manual" and
the WDOE "Stormwater Management Manual" could be used as a resource
document. This is also the area where the Endangered and Threatened Species
issue will result in the greatest impact.
Requirements of this MCM include both Non -Structural BMPs and Structural
BMPs. Some practical BMPs in each of these categories are as follows:
• Non -Structural BMPs
• buffer strips
• riparian zone preservation
• minimize site disturbance
• minimize impervious areas
• source controls
• land use planning
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• Structural BMPs
• storage/detention
• oil separators
• catchbasin design
• dry -well construction
• natural site infiltration
The Post -Construction Runoff Control MCM will include "design criteria" for
calculating stormwater runoff, flow control, street drainage, storm inlets, etc. The
City could update the "Drainage Criteria and Design Manual" to reflect practices
specific to Yakima, and create another opportunity for the "Public
Participation/Involvement" MCM.
Review and permitting of non-structural and structural BMP's, compliance with
"design criteria", working with industrial and commercial land owners on source
control, and other Post -Construction Runoff Control MCM's would likely require
the equivalent of one full-time position.
This MCM includes certain capital costs. To provide for riparian zone
preservation, and to incorporate the "design criteria" into existing storm drainage
system facilities, the City will need to purchase property (or the development
rights to properties). Reconstruction of existing storm drain discharges to surface
water with infiltration ponds/sediment ponds, grassy swales, etc. would also
require capital. The "Comprehensive Storm Water Management Plan" included
$3.7 million in purchase of lands and construction of "water quality ponds" to
treat runoff from existing outfalls. Protection of the riparian zone could easily add
$2.0 million for purchase of properties. Enhancement of surface waters which
would improve habitat to comply with the Endangered Species Act could increase
capital expenditures by $3.0 to $5.0 million, even with volunteer group
participation in water quality restoration projects. The equivalent annual debt
service cost for $10.0 million is approximately $1.0 million per year for 20 years
at 8 percent interest.
➢ Pollution Prevention/Good Housekeeping. Developing and implementing a
program with the goal of preventing or reducing pollutant runoff from municipal
operations. The program must include municipal staff training on pollution
prevention measures and techniques (e.g., regular street sweeping, reduction in the
use of pesticides or street salt, or frequent catch -basin cleaning).
Yakima Impacts. This MCM could be as intense as the City of Yakima want to
make it. The goal would be established by the City of Yakima based on local
conditions. The EPA Phase II Storm Water Regulations are designed to reduce
the quantity of pollutants to the "maximum extent possible", not eliminate them
entirely as may be inferred from the WDOE regulations.
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Individual elements of Pollution Prevention/Good Housekeeping may consist of
the following:
• Street Sweeping. For purposes of this discussion, sweeping of residential
areas would be performed on a "quarterly basis", and commercial and
industrial areas on a "monthly basis". With 1 vacuum sweeper and 2
employees, the program would include 16 hours per day, 5 days per week.
This equipment and staffing is in additions to 2 existing street sweepers and 4
full-time employees now performing these activities in the Public Works
Department.
• Catch basin cleaning/Dry-well cleaning. Catch basins may require yearly
cleaning with dry -wells cleaned every 8 to 10 years. For the purpose of this
discussion, cleaning catch basins once per year and dry -wells every 4 to 5
years would require 1 vacuum flush truck and 2 employees. The program
would include 8 hours per day, 5 days per week.
• Sedimentation basin/ditch cleaning. Maintenance activities include removal
of sediments; grass maintenance; removal of brush, weeds, and other
restrictions; and monitoring of private storm water facilities to ensure there
proper operation. For purpose of this discussion, the equivalent of 1 full-time
employee, with the addition of 4 part-time (4-month/summer) employees for
this activity, are anticipated. Equipment includes mowers and grass trimming
equipment.
• Storm drainage cleaning. A preventative maintenance program for storm
drains would include jet cleaning, root removal, and repairs and rehabilitation
as may be needed. A cycle of once every 5 -years may be appropriate. TV
inspection would also be a part of the preventative maintenance program
probably on a 10 -year cycle. Staffing would consist of 2 full-time employees
for jet cleaning etc., and 2 full-time employees for TV inspection, etc.
D Program Administration. Although not directly described in the EPA Phase II
Storm Water Regulations, the administration, management, and ancillary costs of
the Program Administration need to be considered. A full-time program manager
would be responsible for coordination and management of the program. Duties
and responsibilities include regulations; budgeting; reporting; participation in
public presentations and public involvement programs; maintaining City
ordinances; participation in Watershed/Basin planning; working with commercial
and industrial customers; customer response issues; council presentations;
coordination with other City activities; and other duties. A full-time clerical staff
employee would also be required for phone; letters; reports; filing; and other
duties. Ancillary costs include the cost of the WDOE General Permit; fees and
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charges of finance, engineering, public works, managers office, fleet maintenance
etc.; and the assessments/charges of the stormwater utility against public facilities.
10.8.1 Guidelines for Development of Costs
The following guidelines have been used in developing costs of the Stormwater Program
for the City of Yakima.
> Staffing Costs
• Salary - $20/hr; 30% benefits; 39% for overheads (office space, supplies,
computers, etc.). EQUALS $75,000/year/employee.
> Equipment Costs (8% interest rate)
• Service Van - $25,000, 5 -years
♦ Service Vehicle - $20,000, 5 -years
• Street Sweeper (Vacuum) - $140,000, 5 -years
♦ Vacuum/Flush Truck - $250,000, 7 -years
♦ TV Van - $180,000, 7 -years
• Mowers — Tractor ($70,000); Mower ($8,000); Tractor: 5 -years; Mower: 3 -
years
• Monitoring - $8,000/station, 3 -years
• Sampling - $7,000/station, 3 -years
> Maintenance Costs
• Root foaming - $3/foot
• Testing - $200/test (minimum)
10.8.2 Cost Impacts of a Stormwater Utility
Table 10-11 summarizes the cost impacts of a Stormwater Utility as described in this
Section on the City of Yakima.
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Table 10.11 Stormwater Program Costs
Activity
Staffing
Annual
Labor Cost
Equipment
Annual
Equipment
Cost
Total
Annual
Cost
Public Education and Outreach
1 FT
$75.000
Vehicle (1)
$5,000
$80,000
Public Participation/Involvement
-
-
-
-
-
Illicit Discharge Detection and
2.5 FT
$187.500
Service Van (1)
$6.300
$225,400
Elimination
Monitoring (2)
$6,200
Sampling (2)
$5.400
Testing (100)
$20,000
Construction Site Runoff Control
1.5 FT
$112,500
Vehicle (I)
$5.000
$117.500
Post -Construction Runoff Control
1 FT
$75,000
Vehicle (1)
$5,000
$1,080.000
SW Capital ($3.7M)
$370,000
ESA Capital ($6.3M)
$630.000
Pollution Prevention/Good
Vacuum Sweep (1)
$35,000
Housekeeping
Vacuum Truck (I)
$48,000
Street Sweeping
2 FT
$150,000
Vehicle (2)
$10,000
Catch basin/Dry-well
2 FT
$150,000
Mower (1)
$3.100
$942,100
Sedimentation/Ditch
1 FT; 4 PT
$125,000
Tractor (1)
$17,500
Vacuum Truck (1)
$48,000
Storm drain PM
4 FT
$300,000
TV Van (1)
$34.500
Root foaming
--
--
Contract
$21,000
Program Administration
2 FT
$150,000
Vehicle (1)
$5,000
$935,000
City Services/Ancillary Costs
$780,000
TOTALS
17 FT; 4 PT
$1,325,000
--
$2,055,000
$3,380,000
The annual costs of $3,380,000, inclusive of the $1.0 million in capital amortization
(Stormwater - $370,000; ESA - $630,000), is higher than included in the City of Yakima
comments to WDOE dated February 11, 2000 (approximately $1.5 million), but is similar
to the proportional costs that was included in the 1993 "Comprehensive Storm Water
Management Plan" with the addition of the ESA debt service cost. The current estimate
of annual costs includes increased staffing (from 10 to 17); the amortization of all
equipment; and ancillary costs that was not fully identified in the February 11 evaluation.
The $1.0 million in capital cost amortization of $10.0 million is also higher than
identified in the February 11 evaluation and incorporates Endangered and Threatened
Species mitigation.
10.8.3 Implementation
The implementation of the stormwater management program is expected to occur over a 4
to 5 year period. The following identifies the staffing and activities which may occur.
➢ Year 1 (2003)
• Staffing:
• Program Manager
• Public Relation Specialist
• Clerical Assistant
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• Activities:
• Initiate Public Education and Outreach
• Initiate Public Participation/Involvement
- Develop Design Criteria Manual
- Develop Construction Site Runoff Control
• Develop Pollution Prevention/Good Housekeeping Plan
• Develop Capital Improvement Projects
• Submit Grant/Loan Applications
> Year 2 (2004)
• Staffing:
• Illicit Discharge Staffing (2.5)
• Construction Site Runoff Control Staffing (1.5)
• Post -Construction Runoff Control Staffing (1)
• Street Sweeping (2)
♦ Activities:
• Continue Year 1
• Initiate Volunteer Program
• Adopt Stormwater Utility
• Initiate Illicit Discharge Detection Program
• Initiate Design Criteria Standards
• Initiate Construction Site Control Program
• Initiate Post -Construction Runoff Control Program
• Identify properties to be purchased for "water quality ponds"
• Initiate Street Sweeping Program
> Year 3 (2005)
• Staffing:
• Catchbasin/Dry-well Staffing (2)
• Activities:
• Continue Year 1 and Year 2
• Purchase properties for "water quality ponds"
• Initiate "water quality pond" construction
• Initiate Catchbasin/Dry-well Program
• Identify properties to be purchased for "riparian habitat"
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➢ Year 4 (2006)
• Staffing:
• Sedimentation/Ditch Staffing (1 plus 4)
• Storm Drain PM (Cleaning) Staffing (2)
• Activities:
• Continue Year 1, Year 2, and Year 3
• Purchase properties for "riparian habitat"
• Initiate volunteer "riparian habitat" restoration projects
• Initiate Sedimentation/Ditch Program
• Initiate Storm Drain PM Program (Cleaning)
➢ Year 5 (2007)
• Staffing:
• Storm Drain PM (TV inspection) Staffing (2)
• Activities:
• Continue Year 1 through Year 4
• Initiate Storm Drain PM Program (TV inspection)
• Initiate Root foaming
• Initiate capital "riparian habitat" restoration projects
Based on this 5 year implementation schedule, yearly costs for the stormwater
management program would be as shown in Table 10-12.
Table 10-12. Stormwater implementation Schedule
Activity
2003
2004
2005
2006
2007
Public Education and Outreach
$80,000
$80,000
$80,000
$80,000
$80,000
Public Participation/Involvement
--
--
--
--
--
Illicit Discharge Detection and Elimination
--
$225,400
$225,400
$225,400
$225,400
Construction Site Runoff Control
--
$117,500
$117,500
$117,500
$117,500
Post Construction Runoff Control
--
$80,000
$450,000
$550,000
$ I,080,000
Pollution Prevention/Good Housekeeping
--
$185,000
$383,000
$736,600
$942,100
Program Administration
$155,000
$155,000
$155,000
$155,000
$155,000
City Services/Ancillary Costs
$65,000
$236,000
$395,000
$522,000
$780,000
TOTAL
$300,000
$1,078,900
$1,805,900
$2,386,500
$3,380,000
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SECTION 11
IDENTIFICATION OF SELECTED
WASTEWATER COLLECTION STRATEGIES
11.1 Summary
Section 11 presents the spreadsheet model analysis of the Yakima collection system, City
of Yakima's analysis of the collection system, and a summary of the Yakima collection
system expansion alternatives. Section 11 remains unchanged from the 2000 Draft
Wastewater Facilities Plan prepared by HDR Engineering Inc. The Draft Facilities Plan
Section 11 is included in the Appendix and is incorporated in this report by reference.
City of Yakima Wastewater Facility Plan - DRAFT 2/26/04 Page 11-1
DRAFT
City of Yakima
Mandatory Wastewater Facilities Plan
SECTION 11
Identification of Selected
Wastewater Collection Strategies
September 2000
prepared by
Clint Dolsby
HDR Engineering, Inc.
reviewed by
John Koch
Tony Krutsch
City of Yakima
DRAFT
Table of Contents
11.1 Introduction 1
11.2 Development of the Opinion of Probable Costs 2
11.3 Service Area Agreements 3
11.4 Spreadsheet Model Analysis of the Collection System 3
11.4.1 Development of Flow Projections 3
11.4.1.1 Existing Flow Projections 3
11.4.1.2 Build -Out Flow Projections 4
11.4.2 Spreadsheet Model Computation of Flows 4
11.4.2.1 Spreadsheet Collection System Model Development 4
11.4.3 The Spreadsheet Collection System Model Analysis of Existing and
Future Flows 7
11.4.3.1 Collection System Interceptor Extensions 9
11.4.3.2 Collection System Interceptor Extensions Costs 14
11.5 Yakima's Analysis of the Collection System 16
11.5.1 Suntides/Gleed Basin 17
11.5.2 Cowiche Canyon Basin 18
11.5.3 Wide Hollow Basin 18
11.5.4 Coolidge Basin 19
11.5.5 Wiley City Basin 19
11.5.6 Airport West Basin 19
11.5.7 Airport South Basin 20
11.5.8 West Washington Basin 20
11.5.9 Summary of Interceptor Extension Projects 21
11.5.10 Collection System Interceptor Extensions Costs 21
11.5.11 Impact of Growth in the Urban Reserve 23
11.6 Summary of the Yakima Collection System Expansion Alternatives 26
11.7 Rudkin Road Pumping Station 26
11.8 Collection System Resource Requirements 27
11.9 Stormwater and Stormwater Resource Requirements 28
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City of Yakima
SECTION 11
Identification of Selected Wastewater
Collection Strategies
11.1 Introduction
The purpose of this Section is: (1) to present the existing baseline and future build -out
interceptor replacement projects that are recommended from a spreadsheet model of
existing and future conditions, and to present those interceptor extensions recommended
by the City of Yakima resulting from population growth within the Yakima Urban Area
and; (2) to document the flows for both of the methods that are presented. Flow
projections are integral to the Yakima Comprehensive Plan because they help to identify
the appropriate size of wastewater collection and treatment facilities under consideration.
In order to present the development of the flows this Section is divided into subsections.
The first section describes how the collection system spreadsheet model was developed
and outlines important criteria that were built into the spreadsheet such as data on
sewerage basins, planned land use, housing density, point source flow information,
amount of land already connected to sanitary sewers, and similar factors. The spreadsheet
model routes the wastewater flow through the collection system sewer network, and the
projections are compared with the capacity available in existing facilities. This
subsection also presents the general methodology used in the development of Yakima
Comprehensive Plan flows for the spreadsheet model. A land use based methodology has
been used to prepare a link with the local governments where the Yakima Wastewater
Division provides service, and to acknowledge the contribution of commercial and
industrial (non-residential) wastewater to capacity needs. Land use data from the City of
Yakima Geographic Information System (GIS) forms the base of the flow estimates for
the Yakima Urban Area and Yakima Urban Reserve area.
The second subsection presents a summary of the Future Sewer Planning Draft Report
prepared by the City of Yakima. This report estimates build -out flow projections for the
Yakima Urban Reserve area, and routes new interceptor extensions to convey this flow.
The new pipelines and laterals have been developed for each basin in the Yakima Urban
Reserve.
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The results from these two analyses are compared in the last subsection and a few options
are presented for the expansion of the Yakima collection system. As the Yakima Service
Area population continues to grow, the expansion of the collection system will include
some of the results from the spreadsheet model, and the City of Yakima Future Sewer
Planning Draft Report.
A computer model from Hydragraphics, a commercial modeling package produced by
Pizer Inc., is available to evaluate the flow projections in terms of their impacts on the
treatment plant and the collection system. Information assembled about the existing
collection system and proposed improvements, as well as the sanitary and wet weather
flows that are experienced in the system, is entered into the model. The model uses this
information to predict the total accumulated flow at the treatment plant. It is also capable
of identifying those sewer lines and lift stations in the existing system that might not be
able to accommodate the expected flows under different flow conditions. The use of this
model is recommended and will provide a useful method to analyze different flow
conditions, and collection system layouts, for the City of Yakima.
11.2 Development of the Opinion of
Probable Costs
The opinion of probable cost is an estimate for building facilities. Opinion of probable
costs can be expected to undergo long term changes in keeping with the national and local
economy. One of the best available barometers of these changes has been the
Engineering News Record Construction Cost Index (ENR -CCI), which is computed from
prices of construction materials and labor and is based on a value of 100 in the year 1913.
Construction costs have been steadily increasing for many years. It is believed that the
ENR -CCI for the Seattle area is representative of the construction costs in the Yakima
area. For the costs presented in this report, an ENR -CCI value of 7,000 is used which
corresponds to the level of the ENR -CCI in January 2000.
The sources of the opinion of probable cost are:
➢ Cost data for recent HDR designed WWTP expansion and wastewater collection
system projects adjusted to 2000 dollars.
➢ Recent costs for other similar facilities adjusted to regional market conditions and
2000 dollars.
Factors for allied costs were developed from recent construction projects. These factors
are presented in Table 11-1.
Table 11-1. Summary Allied Cost Factors
Cost Factor Mark-up Used in Summary Estimates
Contractor Overhead and Profit 15%
Contingencies 20%
Sales Tax 8%
Engineering, Legal and Fiscal 25%
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11.3 Service Area Agreements
The City of Yakima, Yakima County, the City of Union Gap, and the Terrace Heights
Sewer District have entered into a long-term service agreement. The general principles
incorporated into the agreement include the following:
D The City of Yakima will retrofit, expand, and continue to operate the Yakima
Regional WWTP to treat the wastewater generated by the entire Yakima Urban
Area including Union Gap and Terrace Heights.
D Sewers to unincorporated areas will be developed by the City of Yakima, the City
of Union Gap, or Terrace Heights Sewer District unless an agreement cannot be
reached, in which case Yakima County may develop the systems.
D A system of wastewater treatment charges will be developed based on the flow
and strength of the wastewater received from the various parties according to
formulas that have been developed.
11.4 Spreadsheet Model Analysis of the
Collection System
11.4.1 Development of Flow Projections
The flow projection methodology used to estimate wastewater flows is based on the
adopted land use categories from the Yakima Urban Area Comprehensive Plan, and the
level of service standard for sanitary sewers of 235 gallons per capita day. This flow
factor includes 80 gallons per capita day (gpcd) of residential flow, 48 gpcd of infiltration
and 107 gpcd of inflow. The method approximates the existing connections to the sewer
system and the projected densities for each land use categoryof each sewerage subbasin.
11.4.1.1 Existing Flow Projections
Estimates of wastewater under existing conditions were based on the acreage of each land
use category within each subbasin, residential and commercial densities, and flow factors.
Residential Flow Component
The total number of Residential Equivalent (RE) units currently connected to the sewer
system was obtained directly from a query of the sewer billing database. The residential
flow factor of 80 gallons per capita day was estimated as part of the calibration effort.
Commercial and Industrial Flow Components
Existing commercial and industrial acreage resulted from a GIS query of the sewer billing
database. A sewage flow of 1,000 gallons per acre per day (gpad) was used to
approximate the commercial contribution, and 2,000 gpad comprises the industrial
contribution.
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Calibration of Existing Flows
Sewer subbasins were grouped into larger basins. Estimated flows from the collection
system were compared with measured flows at the plant and the flow factors were
modified based on the comparison. This approximate method showed that a flow factor
of 235 gallons of wastewater per capita day for the residential average annual flow
approximates the actual volumes of wastewater generated at the Yakima Regional
WWTP for peak hour wastewater flow conditions.
11.4.1.2 Build -Out Flow Projections
Estimates of future influent wastewater under build -out conditions were projected based
on the build -out acreage of each land use category within each subbasin, residential,
commercial, and industrial densities, and flow factors. Build -out flow projections were
calculated using the relationships developed in the evaluation of existing flow
projections.
Residential Flow Component
The Comprehensive Plan establishes a range of maximum allowable residential densities
for each land use category. For the future flow projections, build -out residential densities
are based on existing fully developed densities in areas of comparable land use. These
densities have been applied to the residential acreage to generate residential equivalents
for each land use category for each subbasin. The same flow factors used for the existing
residential flows were used for build -out flows.
Commercial and industrial Flow Components
Commercial and industrial flows were calculated by applying the flow factors to the
build -out sewered commercial and industrial acreage. The flow factor (gallons of
wastewater per acre) was based on total sewered acreage of commercial and industrial
areas.
11.4.2 Spreadsheet Model Computation of Flows
Flow projections for the existing Yakima Regional WWTP were estimated using a
collection system spreadsheet model. Pertinent data for preparation, calibration, and
operation of the spreadsheets was developed based upon a general flow projection
methodology.
11.4.2.1 Spreadsheet Collection System Model Development
The collection system spreadsheet flow generation model was based on the files received
from the City of Yakima detailing the collection system sewers and physical
configuration. Land use data defining the residential units in the existing system was
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combined with commercial and industrial land acreage information to generate sewage
flow.
Information was assembled about the existing collection system and proposed
improvements, as well as the sanitary and extraneous flows experienced in the system.
The spreadsheets used this information to predict the total accumulated flow at the
existing Yakima Regional WWTP. Data entered into the system model, including the
collection system and the service area input, is discussed in the following sections.
Collection System
The bulk of information about the collection system was stored in several files in the City
of Yakima's GIS system. These files house the location of every pipe, manhole, and lift
station included in collection system. This data includes invert elevations, pipe slopes,
pipe diameters, pipe material, pipe length, and other necessary pieces of information.
From this information, and the existing collection system analysis, a future layout of the
pipes that were accounted for in the existing system layer, and many of the proposed new
parallel pipes, were created. This set of data served as the starting point for the creation
of a future collection system layer to model the collection system as it would appear
under build -out conditions.
Parallel pipes were added to collect future flow from the service areas. The alignment of
these new pipes was selected based on an analysis of the collection system. Alignments
are conceptual and represent the limited level of development possible in a planning
study. Where the sizes were not specified, new pipes were expected to be buried
approximately 15 feet below ground with a nominal diameter based on the flow, an
identical slope to the existing parallel interceptor, and a friction factor value of 0.013.
The actual size of these future interceptors will be determined after further analysis of the
expected flows. The required Yakima Regional WWTP capacity is based on the
accumulated flow at the outlet of the collection system.
In the event that a review of the available topographic information shows that not all
potential future service areas would drain to existing facilities by gravity alone, new lift
stations may be added to the collection system layer to overcome topographic features.
These future lift stations will be assigned a set of default parameters in order to pump the
flows entering the wet well, with little storage attenuation and no flow loss due to
overflows.
Sewer Service Subbasins
The spreadsheet model uses a set of subbasins, referred to as sewer service subbasins to
add flows into the collection system. Each service area is a geographic area that is
anticipated to contribute its sanitary flow into the collection system at a single manhole.
The flow addition is based on the designated land use for each service area.
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The sewer service subbasins consisted of a set of polygons covering the geographical area
under consideration. Each polygon contains information about residential, commercial
and industrial land use. The information is expressed in terms of population, dwelling
units, or other information contributing wastewater flow, such as acres of commercial
land. The basin borders have been relocated where subbasins intersected several
collection system lines in an attempt to separate the flow to the different collection
system lines.
The existing sewer service subbasins layer represented properties currently connected to
the sewer system. The number of connections was based on 1990 census data on
population and the number of dwellings increased 1 percent per year to 1999. In this
layer, each service area was assigned the number of residential dwelling units that were
currently located within that service area based on GIS data. Each service area
(geographic land area) in the existing conditions layer contained the number of acres
designated as industrial and commercial land use. The flows from currently connected
industrial and commercial land uses were input directly in gallons per day for each
service area. Total sanitary flow from the existing system to the Yakima Regional
WWTP was calibrated to the 1997-1999 average and maximum treatment plant flows.
The future sewer service subbasins were intended to represent future conditions when
each polygon is fully developed. Three important values were altered for each land use
polygon: the number of residential dwelling units; the commercial flow contribution; and
the industrial flow contribution.
Future Residential Flow
The developed residential area for each land use polygon was calculated by projecting the
build -out housing units, based on an annual growth rate of 1 percent. The future dwelling
units at build -out were divided by the planned density for the land use designation to
arrive at the developed residential area within the polygon under future land use
conditions. Future dwelling units were added to the existing dwelling units to find the
total number of dwelling units in each polygon, while the flow contribution per dwelling
unit was maintained at 235 gallons per capita per day, including the influences of
infiltration and inflow.
Future Commercial and Industrial Flow
The developable commercial and industrial area for each polygon was calculated in a
manner similar to the method used for residential land use. Each acre of future
commercial development was multiplied by a flow contribution of 1,000 gallons per acre
per day and industrial development was multiplied by 2,000 gallons per acre per day. For
each land use polygon, the flow contribution from future development was added to the
existing flow to yield a total commercial or industrial flow contribution.
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11.4.3 The Spreadsheet Collection System Model
Analysis of Existing and Future Flows
The collection system spreadsheet model has been used to approximate and route
projected flows through the existing sewer network to the Yakima Regional WWTP.
Estimates have been made for two scenarios of the peak flows which define maximum
hydraulic conditions for the collection system, treatment plant, and effluent outfall. One
scenario routes most of the flow to the Yakima Regional WWTP through the Rudkin
Road pumping station, overloading the interceptors adjacent to the station. Scenario two
bypasses much of the flow past the Rudkin Road pumping station resulting in some
overloaded interceptors along the way.
The spreadsheet model considers a pipe to be over capacity when the maximum depth
calculated at the projected flow is more than 85 percent of the pipe diameter (d/D = 0.85).
This corresponds to an allowable flow of approximately 89 percent of the full flowing
conduit capacity. If the total flow is more than 89 percent of capacity the spreadsheet
identifies the sewer as overloaded. The maximum flow may occur for a short time (one
or two hours) and the average flow may be less than the capacity criteria. This planning
level analysis does not account for potentially acceptable levels of sewer surcharging for
pipelines that are buried relatively deep and are not near connected basements.
Existing and build -out peak flows generated in the service area, routed through the
existing collection system for both scenarios, result in interceptors exceeding capacity
under the projected flows as highlighted in Tables 11-2, 11-3, 11-4 and 11-5. These
capacity problems can be caused by increased development within the existing service
area, or by the introduction of new flows from outlying service areas both within the
existing Urban Growth Boundary and the Urban Reserve Boundary.
Table 11-2. Interceptors Projected to Exceed Capacity in the Existing Peak Flow
Condition for the Rudkin Road Flow Scenario'
Subbasin From Manhole Pipe Diameter, Pipe Length, Estimated Capacity, Existing Peak Wet
Number Number in ft cfs Weather Flow, cfs
111G E28MH76 3112 8 437.7 0.73 1.04
217 E21MH17 4975 15 369.5 1.13 2.52
305A W20MH3A 4169 8 346.0 0.06 0.26
307 W5MH36 15 8 171.4 0.22 0.52
309 W6MH53 21 15 278.1 1.14 1.39
416 E8MH73 1675 18 168.3 3.53 6.74
418 W 17MH2 2368 18 488.5 6.04 6.262
508 W32MH4A 2874 18 495.6 6.14 6.212
509 W32MH7 581 18 420.1 1.77 3.24
516 W29MH37 5103 8 316.9 0.22 0.39
520A W54MH6 4603 8 305.4 1.44 1.97
1. Data from spreadsheet collection system model with existing peak flows.
2. These interceptors will be operating between 89 and 100 percent of the full flowing capacity.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 7
DRAFT
Table 11-3. interceptors Projected to Exceed Capacity in the Existing Peak Flow
Condition Rudkin Road Flow Bypass Scenario'
Subbasin From Manhole Pipe Diameter, Pipe Length, Estimated Capacity, Existing Peak Wet
Number Number in ft cfs Weather Flow, cfs
111G E28MH76 3112 8 437.7 0.73 1.04
217 E21 MH 17 4975 15 369.5 1.13 2.52
305A W20MH3A 4169 8 346.0 0.06 0.26
307 W5MH36 15 8 171.4 0.22 0.52
309 W6MH53 21 15 278.1 1.14 1.39
414 EI7MH4 400 8 74.8 0.74 4.54
509 W32MH7 581 18 420.1 1.77• 3.24
516 W29MH37 5103 8 316.9 0.22 0.39
520A W54MH6 4603 8 305.4 1.44 1.97
1. Data from spreadsheet collection system model with existing peak flows.
Table 11-4. Interceptors Projected to Exceed Capacity in the Build -Out Flow
Condition for the Rudkin Road Flow Scenario'
Subbasin From Manhole Pipe Diameter, Pipe Length, Estimated Capacity, Projected Build -Out Peak
Number Number in ft cfs Wet Weather Flow, cfs
111G E28MH76 3112 8 437.7 0.73 1.04
202 E30MH16 2374 24 367.1 10.67 11.972
212 E21MH11 480 24 389.2 10.27 11.73
215 W4MH26 2468 8 269.8 0.77 1.12
217 E21 MH 17 4975 15 369.5 1.13 4.47
23213 E21MH55 466 18 137.9 6.01 6.95
305A W20MH3A 4169 8 346.0 0.06 0.29
307 W5MH36 15 8 171.4 0.22 0.58
309 W6MH53 21 15 278.1 1.14 1.55
404 E62MH2 526 30 512.4 11.40 21.99
406 E56MH3 5443 30 649.1 11.47 21.68
407 E40MH5B 5448 21 606.0 11.47 20.05
412 E41MH13 5453 21 528.1 8.39 18.88
416 E8MH73 1675 18 168.3 3.53 17.53
418 W 17MH2 2368 18 488.5 6.04 16.73
506 W31MHIO 4013 8 229.5 1.62 1.642
507 W 17MH92 2106 21 382.0 9.89 16.80
508 W32MH4A 2874 18 495.6 6.14 16.64
509 W32MH7 581 18 420.1 1.77 8.69
516 W29MH37 5103 8 316.9 0.22 1.05
517 W3IMH7 4007 12 611.7 2.64 6.34
520A W54MH6 4603 8 305.4 1.44 5.29
521A W54MH35 4597 12 677.5 2.42 2.622
532B W68MH56 2857 8 691.8 0.78 0.97
542 WIOIMH13 3265 10 252.8 1.49 1.572
1. Data from spreadsheet collection system model with build -out peak flows.
2. These interceptors will be operating between 89 and 100 percent of the full flowing capacity.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 8
DRAFT
Table 11-5. Interceptors Projected to Exceed Capacity in the Build -Out
Flow Condition for the Rudkin Road Flow Bypass Scenarios
Subbasin From Manhole Pipe Diameter, Pipe Length, Estimated Capacity, Projected Build -Out Peak
Number Number in ft cfs Vet Weather Flow, cfs
IIIG E28MH76 3112 8 437.7 0.73 1.04
202 E30MH 16 2374 24 367.1 10.67 11.972
212 E21MH11 480 24 389.2 10.27 11.73
215 W4MH26 2468 8 269.8 0,77 1.12
217 E21 MH 17 4975 15 369.5 1.13 4.47
232B E21MH55 466 18 137.9 6.01 6.95
305A W20MH3A 4169 8 346.0 0.06 0.29
307 W5MH36 15 8 171.4 0.22 0.58
309 W6MH53 21 15 278.1 1.14 1.55
401 E641 W45 763 24 415.5 15.17 22.36
412A E17MH95 5194 27 334.8 8.87 10.92
414 E17MH4 400 8 74.8 0.74 11.46
416A E8MH73 1675 18 168.3 3.53 7.03
418 W 17MH2 2368 18 488.5 6.04 6.412
501 E42MH90 3640 30 450.4 15.48 15.852
503 E32MH91 3469 27 247.4 8.65 11.08
506 W31MH10 4013 8 229.5 1.62 1.642
507 W17MH92 2106 21 382.0 9.89 10.482
508 W32MH4A 2874 18 495.6 6.14 10.32
509 W32MH7 581 18 420.1 1.77 8.69
516 W29MH37 5103 8 316.9 0.22 1.05
517 W3IMH7 4007 12 611.7 2.64 6.34
520A W54MH6 4603 8 305.4 1.44 5.29
521A W54MH35 4597 12 677.5 2.42 2.622
532B W68MH56 2857 8 691.8 0.78 0.97
542 W 101 MH 13 3265 10 252.8 1.49 1.572
1. Data from spreadsheet collection system model with build -out peak flows.
2. These interceptors will be operating between 89 and 100 percent of the full flowing capacity.
11.4.3.1 Collection System Interceptor Extensions
The pipelines shown in Tables 11-2, 11-3, 11-4 and 11-5 are too small to convey the
existing and/or build -out flows. These capacity problems are caused by increased
development within the existing service area. Existing and future improvements that run
parallel to an existing sewer, shown in Tables 11-6, 11-7, 11-8 and 11-9 and Figures 11-1
and 11-1A, have been developed for the Yakima collection system to alleviate the
capacity problems. Since the collection system model provides an approximate method
of routing the wastewater flow through the collection system, these improvements should
be refined prior to their implementation. This will provide a more detailed approach to
incorporating them into the Yakima collection system.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 9
c
8
A
6 1 5 1 4 1 3 1
2
SCALE
1500 0 1500 3000
SCALE
LEGEND:
FEET
EXISTING SANITARY SEWER PIPING
PARALLEL PIPES REQUIRED .•'
W68MH56
W101MHI3
•
/
(yi
•
FRUITVALE BOULEVARO
—1_1_
W4V1126
E211.1H55
W LINCOLN AVENUE
Ei1M1-117
E21MH59
ETIMH11
E28MH76
E YAKIMA AVENUE
..._
SUMMITVIEW AVENUE
Iv
11ETON ORME
5 72N0 AVENUE
WIDE HOLLOW ROAD
. _
ZIER ROAD
E MEAD AVENUE
E30MH16
INTERSTATE 82
YAKIMA
REGIONAL 51N/TP
r
AFITANLIV ROAD _
W WASHINGTON AVENUE.
W31NH10
W32MH7
W32MH4A
W20MH3A
W5MH36
W17MH02
W17MH92
zx
RUDKIN ROAD
r
S 16TH AVENUE
E62MH2
E4IMH13
W6MH53 E40MH58
E8MH73 E56MH3
_ M
ANTANUROAD
•
FR
HDR Engineering, Inc.
•
CITY OF YAKIMA
YAHMA REGIONAL
WASTEWATER TREATMENT
FACIUTY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drown
E. MCDERMOTT
Checked
Project Number
06539-035-002
Dote
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE INC14, SCALE ACCORDINGLY.
13
0
0
z
BUILD -OUT
SPREADSHEET
MODEL COLLECTION
SYSTEM RUDKIN
ROAD FLOW
THROUGH
IMPROVEMENTS
Fg ure Number
11-1
5
4
1500 0
SCALE "
1500 3000
SCALE
LEGEND:
FEET
EXISTING SANITARY SEWER PIPING
PARALLEL PIPES REQUIRED
W66M H56
WI01MH13
SUMMITVIEW AVENUE
r
FRUNVALE BOULEVARD
W4MH26
E21MH55
W LINCOLN AVENUE.
E21MH17
E21MH11
E28MH78
E YAKIMA AVENUE
ENGLEW000 AVENUE
k
SUMMI7VI AV UE
TIETON ORNE-
5 72ND AVENUE
WIDE HOLLOW ROAD
ZIER ROAD
BOULEVARD
AHTANUM ROAD .,
NOB
W54MH35
W54MHB
W29MH37
S 40TH AVENUE
HILL OOUL_ARD
E MEAD AVENUE
INTERSTATE 82
W WASHINGTON AVENUE
W31MH7
W31MH10
W32MH7
W32MH4A
E30MH16
E611W45
YAKIMA
REGIONAL SWTP
E42MH90
HDR Engineering, Inc.
•
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACIUTY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
RUDKIN ROAD
W2OMH3A
W5MH36
W17MH02
W17MH92
5 16TH AVENUE
E17MH4
EI7MH95
WSMH53
E8MH73
AHTANUM ROAD
E32MH91
THIS UNE IS ONE INCH WHEN
DRAWING S FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
0
0
0.
zo
BUILD -OUT
SPREADSHEET
MODEL COLLECTION
SYSTEM RUDKIN
ROAD BYPASS
IMPROVEMENT
Figure Number
11 -la
DRAFT
Table 11-6. Existing Collection System Expansion for the Rudkin Road Flow
Scenario'
Subbasin From Manhole Parallel Pipe Parallel Pipe Parallel Pipe Estimated Pipe
Number Number Diameter, in Run Length2, ft Capacity, cfs
111G E28MH76 3112P 8 437.7 0.44
217 E2IMHI7 4975P 18 369.5 1.84
305A W20MH3A 4169P 10 346.0 0.39
307 W5MH36 15P 10 171.4 0.39
309 W6MH53 2IP 10 278.1 0.27
416 E8MH73 I675P 15 168.3 3.56
418 W I7MH2 2368P 8 488.5 0.38
508 W32MH4A 2874P 8 495.6 0.52
509 W32MH7 581P 18 420.1 1.77
516 W29MH37 5103P 8 316.9 0.22
520A W54MH6 4603P 8 305.4 0.67
1. Data from spreadsheet collection system model with build -out peak Flows.
2. Parallel pipe length was assumed to be equal to the pipe run for this analysis. The pipe run was greater than the
existing pipe length most of the time since it represents the length of the entire pipe run that will be replaced.
Table 11-7. Existing Collection System Expansion for the Rudkin Road Flow
Bypass Scenario'
Subbasin From Manhole Parallel Pipe Parallel Pipe Parallel Pipe Run Estimated Pipe
Number Number Diameter, in Length2, ft Capacity, cfs
111G E28MH76 3112P 8 437.7 0.44
217 E21MH17 4975P 18 369.5 1.84
305A W20MH3A 4169P 8 346.0 0.22
307 W5MH36 15P 10 171.4 0.39
309 W6MH53 21P 10 278.1 0.27
414 EI7MH4 400P 15 74.8 3.93
509 W32MH7 581P 18 420.1 1.77
516 W29MH37 5103P 8 316.9 0.22
520A W54MH6 4603P 8 305.4 0.67
1. Data from spreadsheet collection system model with build -out peak flows.
2. Parallel pipe length was assumed to be equal to the pipe run for this analysis. The pipe run was greater than the
existing pipe length most of the time since it represents the length of the entire pipe run that will be replaced.
Table 11-8. Build -Out Collection System Expansion for the Rudkin Road
Flow Scenario
Subbasin From Manhole Parallel Pipe Parallel Pipe Parallel Pipe Estimated Pipe
Number Number Diameter, in Run Length2, ft Capacity, cfs
111G E28MH76 3112P 8 437.7 0.44
202 E30MH16 2374P 12 367.1 1.59
212 E21 MH I I 480P 12 389.2 2.29
215 W4MH26 2468P 8 269.8 0.40
217 E21MH17 4975P 24 369.5 3.97
232B E21MH55 466P 8 137.9 0.99
305A W20MH3A 4I69P 10 346.0 0.39
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 12
DRAFT
Table 11-8. Build -Out Collection System Expansion for the Rudkin Road
Flow Scenario' (Cont)
Subbasin From Manhole Parallel Pipe Parallel Pipe Parallel Pipe Estimated Pipe
Number Number Diameter, in Run Length2, ft Capacity, cfs
307 W5MH36 15P 10 171.4 0.39
309 W6MH53 21P 12 278.1 0.45
404 E62MH2 526P 30 512.4 12.35
406 E56MH3 5443P 27 649.1 12.91
407 E40MH5B 5448P 21 606.0 11.29
412 E41MH13 5453P 21 528.1 11.54
416 E8MH73 1675P 27 168.3 17.08
418 W 17MH2 2368P 21 488.5 10.75
506 W31MHIO 4013P 8 229.5 0.75
507 W17MH92 2106P 18 382.0 7.66
508 W32MH4A 2874P 21 495.6 14.64
509 W32MH7 581P 30 420.1 8.89
516 W29MH37 5103P 15 316.9 1.16
517 1V31MH7 4007P 15 611.7 4.79
520A W54MH6 4603P 12 305.4 4.24
52IA W54MH35 4597P 8 677.5 0.39
532B W68MH56 2857P 8 691.8 0.36
542 W1OIMH13 3265P 8 252.8 0.56
I. Data from spreadsheet collection system model with build -out peak flows.
2. Parallel pipe length was assumed to be equal to the pipe run for this analysis. The pipe run was greater than the
existing pipe length most of the time since it represents the length of the entire pipe run that will be replaced.
Table 11-9. Build -Out collection System Expansion for the Rudkin Road
Flow Bypass Scenario
Subbasin From Manhole Parallel Pipe Parallel Pipe Parallel Pipe Run Estimated Pipe
Number Number Diameter, in Length2, ft Capacity, cfs
111G E28MH76 3112P 8 437.7 0.44
202 E30MH16 2374P 12 367.1 1.59
212 E21MH11 480P 12 389.2 2.29
215 W4MH26 2468P 8 269.8 0.40
217 E21MH17 4975P 24 369.5 3.97
232B E21MH55 466P 10 137.9 1.79
305A W20MH3A 4169P 10 346.0 0.39
307 W5MH36 15P 10 171.4 0.39
309 W6MH53 21P 12 278.1 0.45
401 E641 W45 763P 18 415.5 8.30
412A E17MH95 5194P 18 334.8 3.38
414 EI7MH4 400P 24 74.8 13.77
416A E8MH73 1675P 18 168.3 5.79
418 W 17MH2 2368P 8 488.5 0.82
501 E42MH90 3640P 8 450.4 0.40
503 E32MH91 3469P 21 247.4 2.81
506 W31MHIO 4013P 8 229.5 0.75
507 W 17MH92 2106P 8 382.0 0.99
508 W32MH4A 2874P 15 495.6 5.97
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 1.3
DRAFT
Table 11-9. Build -Out collection System Expansion for the Rudkin
Road Flow Bypass Scenario' (Cont)
Subbasin From Manhole Parallel Pipe Parallel Pipe Parallel Pipe Run Estimated Pipe
Number Number Diameter, in Length2, ft Capacity, cfs
509 W32MH7 581P 30 420.1 8.89
516 W29MH37 5103P 15 316.9 1.16
517 W31 MH7 4007P 15 611.7 4.79
520A W54MH6 4603P 12 305.4 4.24
521A W54MH35 4597P 8 677.5 0.39
532B W68MH56 2857P 8 691.8 0.36
542 W101MH13 3265P 8 252.8 - 0.56
1. Data from spreadsheet collection system model with build -out peak flows.
2. Parallel pipe length was assumed to be equal to the pipe run for this analysis. The pipe run was greater than the
existing pipe length most of the time since it represents the length of the entire pipe run that will be replaced.
The proposed Yakima collection system sewers would operate in parallel with the
existing pipelines. The upstream and downstream elevations would be equal to the
elevations at the existing manholes of the existing sewer lines. At the upstream end of
each parallel capacity improvement, a diversion would be used to channel some, or all, of
the flow into the new pipe. Under peak flow conditions, no overflow events are expected
to occur.
11.4.3.2 Collection System Interceptor Extensions Costs
An opinion of probable cost for existing and future sewer extension, including the allied
cost factors presented in Table 11-1, are summarized in Tables 11-10, 11-11, 11-12 and
11-13.
Table 11-10. Collection System Opinion of Probable Cost for the Rudkin Road
Flow Scenario
From Manhole Parallel Pipe Parallel Pipe Parallel Pipe Opinion of Probable
Number Number Diameter, in Run Length, ft Cost (dollars)
E28MH76 3112P 8 437.7 $103,000
Ell MH 17 4975P 18 369.5 $113,000
W20MH3A 4169P 10 346.0 $80,000
W5MH36 15P 10 171.4 $39,000
W6MH53 21P 10 278.1 $65,000
E8MH73 1675P 15 168.3 $46,000
W17MH2 2368P 8 488.5 $0
W32MH4A 2874P 8 495.6 $0
W32MH7 581P 18 420.1 $128,000
W29MH37 5103P 8 316.9 $74,000
W54MH6 4603P 8 305.4 $71,000
TOTAL $719,000
1. Data from spreadsheet collection system model with build -out peak flows.
HDR ENGINEERING, INC.
CITY OF YAKIh1A
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 14
DRAFT
Table 11-11. Collection System Opinion of Probable Cost for the Rudkin Road
Flow Bypass'
From Manhole Parallel Pipe Parallel Pipe Parallel Pipe Opinion of Probable
Number Number Diameter, in Run Length, ft Cost (dollars)
E28MH76 3112P 8 437.7 $103,000
E2IMH17 4975P 18 369.5 $113.000
W20MH3A 4169P 8 346.0 $80,000
W5MH36 15P 10 171.4 $39.000
W6MH53 21P 10 278.1 $65,000
EI7MH4 400P 15 74.8 $21.000
W32MH7 581P 18 420.1 $128,000
W29MH37 5103P 8 316.9 $74,000
W54MH6 4603P 8 305.4 $71,000
TOTAL $694,000
'Data from spreadsheet collection system model with build -out peak flows.
Table 11-12. Collection System Build -Out Opinion of Probable Cost for the
Rudkin Road Flow Scenario'
From Manhole Parallel Pipe Parallel Pipe Parallel Pipe Opinion of Probable
Number Number Diameter, in Run Length, ft Cost (dollars)
E28MH76 3112P 8 437.7 $103,000
E30MH16 2374P 12 367.1 $0
E21MH11 480P 12 389.2 $96,000
W4MH26 2468P 8 269.8 $64,000
E21 MH 17 4975P 24 369.5 $154,000
E21MH55 466P 8 137.9 $33,000
W20MH3A 4169P 10 346.0 $80,000
W5MH36 15P 10 171.4 $39,000
W6MH53 21P 12 278.1 $66,000
E62MH2 526P 30 512.4 $254,000
E56MH3 5443P 27 649.1 $315.000
E40MH5B 5448P 21 606.0 $225,000
E4IMH13 5453P 21 528.1 $198.000
E8MH73 1675P 27 168.3 $83,000
W17MH2 2368P 21 488.5 $184,000
W31MH10 4013P 8 229.5 $0
W 17MH92 2106P 18 382.0 $115,000
W32MH4A 2874P 21 495.6 $185.000
W32MH7 581P 30 420.1 $214,000
W29MH37 5103P 15 316.9 $86,000
W3IMH7 4007P 15 611.7 $165,000
W54MH6 4603P 12 305.4 $74.000
W54MH35 4597P 8 677.5 $0
W68MH56 2857P 8 691.8 $161,000
WIOIMH13 3265P 8 252.8 $0
TOTAL $2,894,000
1. Data from spreadsheet collection system model with build -out peak flows.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 15
DRAFT
Table 11-13. Collection System Build -Out Opinion of Probable Cost for the
Rudkin Road Flow Bypass Scenarios
From Parallel Pipe Parallel Pipe Parallel Pipe Opinion of Probable
Manhole Number Diameter, in Run Length, ft Cost (dollars)
Number
E28MH76 3112P 8 437.7 $103.000
E30MH16 2374P 12 367.1 $0
E21MH11 480? 12 389.2 $96,000
W4MH26 2468P 8 269.8 $64,000
E21 MH l7 4975P 24 369.5 $154,000
E21MH55 466P 10 137.9 $33.000
W20MH3A 4169P 10 346.0 $80.000
W5MH36 15P 10 171.4 $39,000
W6MH53 21P 12 278.1 $66,000
E641 W45 763P 18 415.5 $124.000
E17MH95 5194P 18 334.8 $100,000
EI7MH4 400P 24 74.8 $33,000
E8MH73 1675P 18 168.3 $50,000
\V17MH2 2368P 8 488.5 $0
E42MH90 3640P 8 450.4 $0
E32MH91 3469P 21 247.4 $90,000
W31MH10 4013P 8 229.5 $0
W17MH92 2106P 8 382.0 $0
W32MH4A 2874P 15 495.6 $135,000
W32MH7 581P 30 420.1 $214,000
W29MH37 5103P 15 316.9 $86,000
W31M117 4007P 15 611.7 $165,000
W54MH6 4603P 12 305.4 $74,000
W54MH35 4597P 8 677.5 $0
W68MH56 2857P 8 691.8 $161,000
W101MH13 3265P 8 252.8 $0
$1,867,000
TOTAL
1. Data from spreadsheet collection system model with build -out peak flows.
11.5 Yakima's Analysis of the Collection
System
In late 1999 the City of Yakima's Engineering Division completed a study of future sewer
expansion focusing on the need for new sewer interceptors, trunks, and the accompanying
manholes and lift stations. Three growth areas were targeted for the study:
➢ The existing Yakima City limits
> The existing Yakima Urban Service Area
➢ The Yakima Urban Reserve
Several parameters were integrated into the flow projections for this study. These
parameters included the Parcel Density (a Low -Density level was used), Population
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 16
DRAFT
Density, and Per Capita sewerage flows, which were estimated from previous
Comprehensive Plans. These factors, listed below, provided the basis of existing and
build -out sanitary sewer flow projections for the basins.
> Residential (low-density was used) — 4 residential units per acre
➢ Population density — 2.8 people per residential unit.
➢ Per capita sewage flow — 100 gpd
> Build -out peaking factor — 3.5
The three growth areas were designated as Zones 1, 2, and 3 as set forth in the City Sewer
Connection Charge Ordinance. Eight major sewer basins were identified within the Zone
2 and Zone 3 growth areas. In addition to the eight major sewer basins requiring trunk
sewers, there are areas of the West Valley that do not currently have sewer service. These
areas have been designated as Fill-in Areas and will eventually be connected to the
existing West Valley Interceptor. Fill-in Areas include the Congdon Orchard Lands, and
the area along Summitview Avenue and Tieton Drive between N. 72nd Avenue and N.
88th Avenue. Interceptor and lateral extensions for the major basins listed below are
described in the sections that follow.
➢ Suntides/Gleed
➢ Cowiche Canyon
➢ Wide Hollow
➢ Coolidge
➢ Wiley City
➢ Airport West
> Airport South
> West Washington
11.5.1 Suntides/Gleed Basin
The Suntides/Gleed basin is located outside of the Yakima Urban Reserve, but was
included in this study. It is approximately 910 acres in size and is characterized by gently
sloping land with occasional small hills. The average slope in the basin is 1 to 2 percent.
At build -out conditions, the flow at an outflow point near the Naches River is projected to
be 6 cfs, and the 20 -year flow is 2.8 cfs.
The trunk pipeline that has recently been completed from downtown Yakima to the
vicinity of N. 6th Avenue and Tamarack will serve the future capacity needs of this basin.
The 27 -inch trunk sewer parallels S.R. 12 and the Burlington Northern Santa Fe, (BNSF)
spur track. At build -out, the Cowiche Canyon area will also be connected to this trunk
pipeline. This intermediate 27 -inch connection pipeline will run from N. 6th Avenue and
Tamarack to the vicinity of S.R. 12 and the Naches River, then on to the Old Naches road
as a 24 -inch pipeline. The slope of the pipeline was estimated to be 0.002.
HDR ENGINEERING, 1NC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 17
DRAW
11.5.2 Cowiche Canyon Basin
The Cowiche Canyon basin is characterized by flat silty creek -bottoms surrounded by
very steep rocky hills and has a total area of approximately 800 acres. The projected
build -out flow for the basin is 5 cfs and the 20 -year flow is 3 cfs.
The study has shown that this basin will require the construction of a 15 -inch pipeline
connecting to the planned 27 -inch pipeline that will parallel S.R. 12 and the Burlington
Northern Santa Fe railway corridor. This 15 -inch interceptor will cross under S.R. 12 and
through private property to Powerhouse Road where it will reduce to a 12 -inch pipeline.
The interceptor will run to the northwest from Powerhouse Road to Cowiche Canyon
Road. After the first 0.75 miles of 12 -inch pipeline, it will reduce to 10 -inches in
diameter. The average slope will be approximately 0.008 for this pipeline.
11.5.3 Wide Hollow Basin
The Wide Hollow Basin encompasses approximately 2,100 acres and is characterized by
lowland, silty creek -bottoms, and rolling, sometimes steep, hills with pronounced swales.
This basin is in the northerly portion of what is known as the West Valley. Current rates
of growth within this basin suggest that it will approach full development of 4 residential
units per acre at build -out. Because of several creek and canal crossing areas, the pipe
slopes were estimated to be minimal (0.005 to over 0.030). Estimated build -out flows
from the Wide Hollow Basin at S. 80th Avenue are nearly 13 cfs and the 20 -year flow
projection is 8 cfs.
An intermediate connection interceptor from the existing West Valley Interceptor in the
vicinity of N. 68th Avenue and the Old Yakima Valley Transportation Company railroad
track alignment to S. 96th Avenue will convey the build -out flows from this basin. This
21 -inch pipeline will have an average slope of 0.007. At S. 96th Avenue the 18 -inch
pipeline will turn to the north to a 12 -inch pipeline at Tieton Drive, where it will extend
west to Pear Avenue. At Pear Avenue, the line will be reduced to 10 -inches in diameter
and extend to a swale area just south of Summitview Avenue. From this point the
interceptor will continue up Summitview Avenue to the Yakima Urban Reserve
boundary.
The proposed Wide Hollow Basin pipeline will eliminate the need for the sewer lift
station in the new Sierra Estates development. Originally, this development was required
to construct a sewer lift station at the northeast corner of the intersection at 96th Avenue
and Tieton Drive. The proposed pipeline will intercept the existing 8 -inch sewer in 96`h
Avenue.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 18
DRAFT
11.5.4 Coolidge Basin
The Coolidge Basin contains approximately 400 acres and is characterized by moderate to
steep grades and large hillsides on each side of a narrow swale. The expected build -out
flow from the basin is 3 cfs and the 20 -year basin flow is 1.5 cfs. Trunk pipeline slopes
will vary from 0.008 to 0.02.
The 12 -inch Coolidge Basin Interceptor will be constructed in W. Washington Avenue
from S. 64`h Avenue to S. 72nd Avenue. This line will turn west and generally follow a
swale area to the terminus of the Coolidge Basin at the Yakima Urban Reserve boundary.
11.5.5 Wiley City Basin
The Wiley City Basin contains approximately 1,850 acres and is characterized by steep
hills with many swales on the northern reaches, and silty lowland areas in the southern
reaches. Wiley City is located in the southern end of the basin. The basin is experiencing
more residential, commercial and warehouse development than the other basins. The
expected build -out flow from the Wiley City Basin is 11 cfs and the 20 -year flow is
approximately 5 cfs at the outflow point at S. 64th Avenue and W. Washington Avenue.
Trunk pipeline slope will average approximately 0.010 throughout the basin.
A trunk pipeline initiating at the State Department of Corrections facility on S. 64th
Avenue south of Washington Avenue and extending to the limits of the Yakima Urban
Reserve at Wiley City in the southern West Valley will convey build -out flows. This 24 -
inch pipeline will extend to Occidental Avenue, where a 12 -inch pipeline will extend to
the west and the main pipeline will be reduced to 21 -inches in diameter, continuing down
S. 64`h Avenue. This line will be routed around the curve in the old Yakima Valley
Transportation Company alignment at Ahtanum Road. As the pipeline crosses 96th
Avenue it will reduce to 18 -inches in diameter. It will be further reduced to 15 -inches
and then to 10 -inches in diameter as it navigates through Wiley City to the edge of the
Yakima Urban Reserve boundary.
11.5.6 Airport West Basin
The Airport West Basin contains approximately 1,000 acres and is characterized by
gently sloping terrain with several creeks and marshy areas. The Spring Creek runoff area
that is influenced by Bachelor Creek is located in this basin. The high water table and flat
terrain of the area will make it more difficult to introduce sewer extensions into the area.
The expected build -out flow from the Airport West Basin is 6 cfs and the 20 -year flow is
approximately 3 cfs. The average slope of the terrain is 1 percent and a slope of 0.0015 to
0.005 will be used for the sewer lines in this basin.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 19
DRAFT
Several large laterals will convey build -out flows in this area rather than a trunk sewer.
The main lateral will begin at the West Valley Interceptor at S. 40th Avenue and W.
Washington Avenue on the north side of the Yakima Airport at McAllister Field. This
lateral will extend across the west end of the airport to the central part of the basin where
Occidental Avenue is located. Two sub -laterals will be extended from this lateral west
toward S. 64th Avenue. One of these sub -laterals will be located in W. Washington
Avenue and the other will be at the end of the main lateral. The build -out flows may
require the addition of one or two additional sub -laterals extending from one or both of
these two east -west pipelines. The size of the laterals will be controlled by the grade and
terrain of the area and has been estimated as 21 -inches for the portion of the pipeline
crossing the west end of the airport, decreasing to 18 -inches and 10 -inches for the
remainder of the pipeline.
11.5.7 Airport South Basin
The Airport South Basin contains 1,100 acres and is characterized similar to the Airport
West Basin, except that the terrain is more irregular with the average slope less than 1
percent. This basin is bounded by Ahtanum Creek on the south; S. 16th Avenue on the
east; the Airport Boundary and Spring Creek on the north; and S. 40th Avenue and S. 46th
Avenue on the west. The expected build -out flow for the Airport South Basin is 5 cfs
(due to terrain limitations) and the 20 -year flow is approximately 3 cfs.
The Washington State National Guard has constructed a 15 -inch sewer trunk into the
Airport South Basin along Ahtanum Road. This pipeline extends to S. 26th Avenue from
the S. Broadway Sewer near S. 10th Avenue. An extension of the 15 -inch pipeline west
along Ahtanum Road to the west basin limits at S. 46th Avenue will complete the trunk
sewer for this basin.
11.5.8 West Washington Basin
Approximately 350 acres of the W. Washington Basin is in the Yakima Urban Reserve,
but the actual drainage basin extends beyond the Urban Reserve boundary. The terrain is
similar to the Coolidge Basin. Build -out basin outflow will be approximately 2 cfs and
the 20 -year flows will be nearly 1 cfs.
An interceptor has been constructed from S. 72nd Avenue extending through the bottom
of the central swale to the West Valley High School campus. This pipeline was installed
and financed by the West Valley School District in 1991 due to a health hazard at the
high school. The existing septic system was failing and sewage was surfacing behind the
high school bleachers. The pipeline is 8 -inches in diameter in order to make it large
enough to accommodate development within the basin limits. It has a slope of 0.0093 at
the southwest corner of Conover Park with upstream slopes in excess of 1 percent. Since
its construction, it has become apparent that the interceptor may not be adequate to
convey the build -out flows. Future basin monitoring will determine if another pipeline
will be necessary in for the W. Washington Basin.
HDR ENGINEERING, INC.
CITY OF YAKIh1A
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 20
DRAFT
11.5.9 Summary of Interceptor Extension Projects
The alignment of each new proposed sewer in the Yakima collection system typically
follows a road or natural drainage. The diameter of each new proposed sewer was
selected based on the projected flows calculated by the City of Yakima. The capacity of
each new pipe depends largely on the slope.
The collection system expansion priorities that have been presented for the Yakima
subbasins, shown in Figure 11-2, represent the conclusions from a study performed by the
City of Yakima. These interceptor extensions will provide sewer service to the Yakima
Urban Reserve area under the build -out flow condition of 20 mgd. Of the eight major
subbasins in the Yakima Urban Reserve area, five will have at least one additional trunk
pipeline, one will have a combination of lateral pipelines, and the W. Washington basin
will be monitored during development in the basin to determine when the existing
pipeline will no longer provide adequate service.
11.5.10 Collection System Interceptor Extensions Costs
An opinion of probable cost for existing and future sewer extensions, including the allied
cost factors, are summarized in Table 11-14.
Table 11-14. Build -out Interceptor System Expansion
Basin Pipe Diameter, in Pipe Length, ft Cost Estimate2
(dollars)
Suntides/Gleed Basin Trunk
Cowiche Canyon Basin Interceptor
Wide Hollow Basin Interceptor
Coolidge Basin Interceptor
Wiley City Basin Trunk
Airport West Basin Laterals
Airport South Basin Laterals
27 18,000 $7,091,300
15 2,435 $590,300
12 4,970 $1,133,400
10 7.000 $1.325,800
21 7,595 $2,301,700
18 5,658 $1,543,200
12 1,320 $301,000
10 3,510 $664,800
12 3,380 $770,800
10 3,810 $721,600
24 1,410 $480,700
21 3,810 $1,154,600
18 5,360 $1,461,900
15 4,830 $1,174,000
10 5,160 $977,300
21 1,350 $409,100
18 1,320 $360,000
10 21,390 $4,051,400
12 2,640 $602,000
TOTAL
$27,111,900
1. From the Future Sewer Planning Trunks report.
2. Base Costs per lineal foot taken from City of Yakima cost histories.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 21
0
"-
8
A
6
SCALE
2000 0 2000 4000
SCALE FEET
LEGEND:
EXISTING SANITARY SEWER PIPING
•••••••••—"— PARALLEL PIPES REQUIRED
1
Ti ETON ORNE
WIDE HOLLOW BASIN INTERCEPTOR
UMMITVIEW AVENUE.
. .
WIDEHOLLOWROAD
_ .
•-•
ZIER ROAD
1
5 72N0 AVENUE
.. •
• . t
t
I i 1
,:•.••,:•,,
_.;...-,)
COW1CH E CANYON BASIN INTERCEPTOR
FRUTIVALE BOULEVARD
SUNTIOES/GLEE0 BASIN TRUNK
NOB HILL BOULEVARD
471110***1
at
megofill Itt k
IP *ICI
"11 4411011, 11601 111
E IIB 80 RO
AM% D
S 40TH AVENUE
COOUOGE BASIN INTERCEPTOR
W LINCOLN :AVENUE
AHTANUM ROAD
W WASHINGTON AVENUE
INTERSTATE 82
WILEY CITY BASIN TRUNK
5 IGTH AVENUE
AIRPORT WEST BASIN LATERALS
r
ANTANUM ROAD
_ . _
YAKIMA
'.REGIONAL WWTP
RUOKIN ROAD
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drown
E. MCDERMOTT
Checked
Project Number
06539-035--002
Date
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY,
8
0
BUILD -OUT
COLLECTION
SYSTEM
IMPROVEMENTS
Figure Number
11-2
- • "
DRAFT
As a portion of the new sewer interceptors, trunks, and appurtenances will be required to
provide service to customers and property located within the Yakima Urban Service Area
(Zone 2) and as the remaining capacity will provide service to those developing lands
which are located in the Yakima Urban Reserve (Zone 3), a proportioning of the opinion
of probable costs to Zone 2 and Zone 3 was performed, based on anticipated Service Area
population, Zone 2 is expected to add approximately 15,000 people to the Service Area at
buildout or 30 percent of the total population to be added to Service Area within Zone 2
and Zone 3. Zone 3 is expected to add approximately 35,000 people to the Service Area
at buildout or 70 percent of the total population to be added to the Service Area within
Zone 2 and Zone 3.
Based on the direct proportioning of the total opinion of probable costs for the new sewer
interceptors, trunks, and appurtenances, of $27,111,900, Zone 2 would be assigned
$8,133,600, and Zone 3 would be assigned $18,978,300.
11.5.11 Impact of Growth in the Urban Reserve
The construction of new interceptors and trunk sewers into the Urban Reserve area will
increase flows in the existing Wastewater Collection System. Table 11-15 and Figure 11-
3 identifies those pipe segments within the existing system impacted, the anticipated
parallel pipe size required to meet the increased flows, and an opinion of probable costs
of the pipe improvements.
Table 11-15. Future Impact of Build -out of Urban Reserve Area on the
Existing Collection System?
From Manhole
Number
E28MH76
W20MH3A
W5MH36
W6MH53
E8MH94
E17MH4
E21 MH55
E21MHI1
W32MH7
E641 W45
E42MH91
E42MH92
E42MH93
E42MH94
E42MH95
E42MH96
E42MH97
E42MH98
E42MH99
E42MH40
E42MH41
Parallel Pipe
Number
Parallel Pipe
Diameter, in
3112
4169
15
21
363
400
466
480
581
763
2683
3007
3006
1802
2376
2677
2678
2397
2396
2398
3486
Revised Cost
Estimate' (dollars)
8 $103,000
10 $80,000
10 $39,000
12 $66,000
18 $113,000
36 $39,000
10 $33,000
12 $96,000
36 $220,000
36 $216,000
36 $244,000
36 $234,000
36 $235,000
36 $33,000
36 $185,000
36 $73,000
36 $111,000
36 $189,000
36 $203,000
36 $149,000
36 $89,000
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 23
DRAFT
Table 11-15. Future Impact of Build -out of Urban Reserve Area on the
Existing Collection S stems Cont
From Manhole Parallel Pipe Parallel Pipe Revised Cost
Number Number Diameter, in Estimate' (dollars)
E42MH42 3485 36 $173,000
E31 MHS 3644 36 $226,000
E32MH90 2375 36 $56,000
E32MH90A 3478 36 $41.000
E32MH92 3468 36 $175.000
E32FE3A 2395 36 $88.000
E32MH93 2394 36 $180,000
E32MH94 3029 36 $258,000
E32MH95 3022 36 $263,000
E32MH97 2502 36 $171,000
E32MH98 3475 36 $173,000
E32MH8 3471 36 $83,000
E17MH92 3470 36 $140,000
E 17MH91 403 36 $276,000
EI7MH16A 402 36 $278,000
E17MH93 656 36 $266,000
E17MH94 3032 36 $165,000
E 17MH96 5192 36 $175,000
E17MH97 5191 36 $169,000
E 17MH98 5190 36 $170,000
E8MH91 2491 36 $173,000
E8MH92 5167 36 $189,000
W17MH92 2106 30 $189,000
E30MH 16 2374 12 $89,000
W4MH26 2468 8 $64,000
E32MH96 2503 30 $79,000
W68MH56 2857 8 $161,000
W32MH4A 2874 30 $246,000
W101MHI3 3265 8 $0
E32MH91 3469 42 $196,000
E42MH90 3640 36 $229,000
W41 MH 10 3822 24 $225,000
W31MH7 4007 15 $165,000
W31 MH 10 4013 8 $54,000
W54MH35 4597 8 $159,000
W54MH6 4603 12 $74,000
E21 MH 17 4975 24 $154,000
W29MH37 5103 15 $86,000
E8MH93 5168 27 $319,000
E 17MH95 5194 42 $265.000
E64MH30 5522 12 $83,000
Total Cost $9,475,000
1. Data from spreadsheet collection system model with build -out peak flows.
2. Base Costs per lineal foot taken from City of Yakima cost histories and the 1988 Yakima
Comprehensive Plan for Sewerage Systems that have been scaled up to the April 1999 ENR -CCI.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 24
DRAFT
As with the new interceptors, trunks, and appurtenances, the total opinion of probable
costs for replacement and rehabilitation of the existing Wastewater Collection System has
been assigned to Zone 2 and to Zone 3 based on contributing population at buildout. Of
the total opinion of probable cost of $9,475,000, Zone 2 would be assigned $2,842,500,
and Zone 3 would be assigned $6,632,500.
11.6 Summary of the Yakima Collection
System Expansion Alternatives
The spreadsheet collection system model prepared for this analysis and the City of
Yakima's analysis of the collection system both concluded that several new pipelines will
be required to convey the build -out flows to the Yakima Regional WWTP and correct
existing system deficiencies. To arrive at these conclusions, the spreadsheet model used a
land based approach with over 100 subbasins contributing flow to the collection system.
The City of Yakima Future Sewer Planning Trunks Report projected flows for each of the
eight basins and developed pipelines to convey the flows to the Yakima Regional
WWTP.
Further development of a computerized collection system model will help with the
alternative analysis. Timing of the service to the new subbasins is also dependent upon
the development opportunity. Existing collection system deficiencies should be given the
highest priority. When plant capacity becomes available, development in those areas now
provided with utility services (both sewer and water) should be given priority. By
encouraging in -filling, the City can postpone investment of public resources in areas
where long periods of time might be necessary to recover initial capital.
11.7 Rudkin Road Pumping Station
The existing capacity of the Rudkin Road Pumping Station can be increased to meet
increasing wastewater flow from the City of Yakima and the City of Union Gap. The
current capacity of 5.6 MGD will likely be adequate to 2015 depending on service area
growth and routing of flows in the Yakima collection system.
At buildout conditions for the City of Union Gap, peak flow at Union Gap's Master Lift
Station is expected to reach 10.17 MGD. Combined with anticipated peak flows from the
Yakima Urban Area, the portion of the Union Gap Service Area served by gravity, and
Urban Reserve Area, peak flows at the Rudkin Road Pumping Station at buildout could
be in excess of 20 MGD or over three times current peak flow capacity.
To provide a capacity in excess of 10.0 MGD at the Rudkin Road Pumping Station will
require expansion of the wet -well capacity, replacement of existing pumping equipment
and electrical equipment, and installation of a parallel 18 -inch pressure main from the
Rudkin Road Pumping Station to the Yakima Regional WWTP.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 26
1500 0
SCALE
LEGEND:
SCALE
1500 3000
giiiiiiiii
FEET
EXISTING SANITARY SEWER PIPING
PARALLEL PIPES REQUIRED
W68MH56
W101MH13
SUKIM ITMEW AVENUE
11ETON ORNE
i
5 72ND AVENUE
WIDE HOLLOW ROAD
ZIER ROAD
i
'W NOB HILL
BOULEVARD
1
L.
i7
ti
FRU ITVALE BOULEVARD
ENGLEWO0D. AVENUE
T c F 1
-11 itiolda
pek ovi
,..„001004•41A
Ittle4i"1141Fra
133 d
nat
W54MH35
.W5 4MH6
W29MH37
S 40TH AVENUE
W WASHINGTON AVENUE
1MH
W31
NH10
W32MH7
W32MH4A
W41MH10 ,
AHTAMU1.1 LOAD
W2OMH3A
W5MH36
W6MH53
WI 7MH92
S 18TH AVENUE
E8MH94
E8MH93
E17MH96, E17MH97
E17MH98, E8MH91,
E8MH92
El 7MH95
E17MH94
W4MH26
E21MH55
W LINCOLN AVENUE
E21MHI7
E21MHII
E28MH76
E YAKIMA AVENUE
E30MH16
E42MH97, E424AH98, E42MH99
42MH95, E421AH96
E42MH93, E42MH94
J- • � ' E42�IH92
i i ! E42MH91
_
I i
1 �B HILL BOULEVARD
111111r1A:i E MEAD AVENUE
misk,
111111
•
il!
E17MH91, E17MHM18A
E171.11493
E17MH4
AHTANUI. ROAD
E42MH40 '
E42MH41, E42MH42,
E31MH5
E32MH91, E32111190,
E3211H90A, E32MH92
•
E32FE3A E321.11193, --
E32MH94, E32MH95 -.
E32MH96
E32MH97, E32MH98 —
E32MH8, El 7MH92
INTERSTATE 82
E64MH30
E641W45
YAKIMA
ti REGIONAL WWTP
£42MH90
RUDKIN ROAD
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Dote
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE N CH, SCALE ACCORDINGLY.
0
BUILD -OUT
SPREADSHEET
MODEL COLLECTION
SYSTEM RUDKIN
ROAD BYPASS
IMPROVEMENT
Figure Number
1 1 -3
DRAFT
The opinion of probable cost to expand and modify the Rudkin Road Pumping Station to
provide a firm capacity of 10 MGD is $780,000. To reach 20 MGD capacity at the
Rudkin Road Pumping Station, the opinion of probable cost is $3,600,000.
As the City of Union Gap is required to pump the majority of wastewater within their
service area from the Master Lift Station to the City of Yakima collection system, an
alternate to repumping these flows at the Rudkin Road Pumping Station would be to have
the City of Union Gap upgrade the Master Lift Station and install a pressure sewer that
discharges directly to the Yakima Regional WWTP. The City of Yakima should request
that the City of Union Gap evaluate this alternative prior to the upgrade of the Master Lift
Station, and/or prior to the City of Union Gap flows exceeding the current purchased
capacity of the Rudkin Road Pumping Station of 3.23 MGD.
11.8 Collection System Resource
Requirements
Section 10, Analysis of Existing Wastewater Collection Facilities, presented the man-
hours required for implementation of a preventative maintenance program for the existing
sewer collection and surface drainage system.
With increased staffing and equipment for the Sewer Collection Program, and with the
new requirements for the Stormwater Utility discussed in this report, additional shop and
administrative facilities will be needed. It is recommended that the existing maintenance
facilities be expanded at their current site by purchase of adjacent properties and
construction of new vehicle storage and administrative facilities. Table 11-16 provides
an opinion of probable cost for additional shop and administrative facilities.
Table 11-16. City of Yakima Shop/Administrative
Description Opinion of Probable Cost
Vehicle Storage (14,400 sf) $864,000
Office/Administration (2,400 sf) $192,000
Restroom/Showers/Lockers (1,200 sf) $120,000
Subtotal $1,176,000
Electrical (15%) $176,400
Site work (20%) $235,200
Subtotal Costs $1,587,600
Contractor Overhead and Profit (15%) $238,100
Subtotal $1,825,700
Contingency (20%) $365,100
Subtotal $2,109,800
Sales Tax (8%) $175,300
Subtotal $2,366,100
Engineering, legal and fiscal (25%) $591,500
Property Purchase $300,000
Total Opinion of Probable $3,257,600
Construction Cost
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 27
DRAFT
11.9 Stormwater and Stormwater Resource
Requirements
The 1993 Comprehensive Storm Water Management Plan recommended adoption of
Alternate 4 by the City of Yakima, City of Union Gap, and Yakima County. Alternate 4
identified the downtown core of the City of Yakima for improved conveyance over
increased infiltration because of the concentrations of vehicular traffic and potential
pollutants, and because of the extensive impervious area present in the downtown core.
Piping the runoff from the downtown core was expected to reduce the risk of accidental
spills contaminating the local groundwater aquifer. Alternate 4 included improvements
and modifications to dry well construction throughout the Metropolitan Yakima Area to
reduce pollutant loadings to groundwater, and installing water quality ponds at each basin
outfall to mitigate water quality issues in the Naches River, Yakima River, and Wide
Hollow Creek. Due to the limited capacity of Wide Hollow Creek at an existing bridge,
mill flume, and a fish ladder at Main Street in Union Gap, a diversion pipeline was
proposed to direct flows in excess of the capacity of the existing facilities. Industrial and
commercial sites would be required to utilize appropriate Best Management Practices
(BMP's) to control runoff water quantity and quality. The opinion of probable cost for
improvements recommended in Alternative 4 for the Metropolitan Yakima Area was
approximately $21 million.
During the public hearings on the adoption of the Comprehensive Storm Water
Management Plan, the City of Yakima elected to withdraw the $15 million capital
improvement project for the construction of the conveyance piping system for the
downtown core from the regional plan. The conveyance piping would be a direct cost of
the City of Yakima rather than a regional cost to be shared by the City, Union Gap, and
Yakima County. The City of Yakima established its spending priorities for the
Metropolitan Yakima Area by recommending initiation of the water quality ponds at
basin outfalls; improvement and modification to drywell construction; construction of
new drywells in areas outside of the Central Business District; and support of the other
recommendations included in Alternate 4.
The 1993 Comprehensive Storni Water Management Plan further recommended that the
City of Yakima, City of Union Gap, and Yakima County establish a Stormwater Utility
for the management, operation, and maintenance of a storm drainage system serving the
Metropolitan Yakima Area. The following activities would be essential elements of the
Stormwater Utility.
➢ Operations and Maintenance — This activity includes a water quality monitoring
program for both dry weather screening, to identify illicit connections, and wet
weather sampling, to establish baseline water quality and improvement or
degradation over time. This activity also includes all maintenance activities to
keep facilities functioning as intended.
➢ Public Education and Involvement Program — This activity includes educating the
public about the impact of personal activities and provides information on
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000 PAGE 28
DRAFT
programs to improve environmental quality such as pollutant source measures,
waste reduction, and adopt a stream.
➢ Capital Improvement Program — This activity includes implementing Alternative
4 discussed above.
The City of Yakima, City of Union Gap, and Yakima County would establish a
Stormwater Utility with an initial rate of approximately $3.00/month Equivalent Billing
Unit (EBU). Once the utility was in place, and the prioritized capital needs have been
identified, the rate would be adjusted to provide the required debt service.
If the City of Yakima, City of Union Gap, and Yakima County are unable to reach
consensus on implementation of a Metropolitan Yakima Area Stormwater Utility, each
agency will be required to implement separate Stormwater programs within their
jurisdiction. The Comprehensive Storm Water Management Plan described the impacts
to the City of Yakima with the implementation of a stormwater program.
HDR ENGINEERING, INC.
CITY OF YA K1AMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 29
12.1 Introduction
SECTION 12
FINANCIAL PLANNING/IMPLEMENTATION
Implementation of a Wastewater Facilities Plan is dependent on development of a
realistic and sustainable Capital Facilities Plan which takes into account various internal
sources of revenue such as rates, fees and connection charges as well potential external
sources such as grants and loans. This implementation and financing program is based
on previously described and documented analyses of the wastewater collection and
treatment systems, projected growth rates and recommended and required improvements
for sustaining growth and meeting regulatory requirements.
This Section of the Plan has been developed using a combination of background
information and data, including the 2000 Draft Wastewater Facilities Plan developed by
HDR Engineering, Inc., and the City of Yakima Wastewater Utility's 2001 Cost of
Service and Rate Study. A general overview of past rates analyses, financial policies of
the City of Yakima's Wastewater Utility and an overview of the revenue requirements
associated with completion of the projects outlined herein are provided. In addition,
project implementation costs are evaluated and potential revenue alternatives that may be
available to the City are discussed.
12.2 Financial Policies/Regulatory Requirements
The primary basis for setting rates and charges for wastewater service is specified in
Section 7.60.010 of the City of Yakima Code:
7.60.10 City to fix and collect wastewater rates and charges
A. The public health, safety and welfare require that city of Yakima
fix and collect wastewater rates and charges upon, and measured by either
quantity of water supplied to the premises or, if metered, the quantity of
wastewater discharged into the wastewater sewer system in the city of
Yakima and in areas outside the corporate limits of the city, for the
carrying and discharge of all wastewater into the wastewater system of the
city of Yakima as presently maintained and operated, together with
additions and betterments thereto and extensions thereof which rates and
charged are fixed by this chapter; provided, that the specifying of service
rates and charges by this chapter shall not affect the financing of
construction of sewers and trunk sewers pursuant to the local improvement
district process, the imposition of a wastewater connection charge or other
alternate means of financing such construction; provided further, the
adoption of rates for service property outside of the corporate limits does
not constitute an undertaking by the city to serve any or all such property
without compliance with other laws, regulations, and policies.
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04
Page 12-1
In order to maintain the ability to apply for and receive certain types of State and Federal
funding to assist in financing required improvements to the wastewater system, the City
of Yakima is obligated to perform biennial cost of service studies. The most recent cost
of service analysis was completed in 2001 and based on preliminary findings and the
initial draft of this Facilities Plan. The more general review of projected revenues and
expenditures contained in this Section are intended to ensure that adequate funds are
available to:
• Support operation and maintenance of the Wastewater Utility;
• Satisfy bond and debt service payment and coverage requirements;
• Maintain adequate capital reserves to accommodate local matches for low interest
loan and grant program financing.
A summary of key regulatory requirements which are put forth in the 2001 Cost of
Service and Rate Study as governing factors in establishing fmancial policies are
summarized below,
• As a recipient of Federal grant assistance the City is required to: "Generate
sufficient revenue to pay the total operation and maintenance costs necessary to
the proper operation and maintenance (including replacement) of treatment
works." 40 CFR 35.929-2(b).
• "The user charge system must be designed to produce adequate revenues
required for operation and maintenance (including replacement). 11 shall provide
that each user which discharges pollutants that cause an increase in the cost of
managing the effluent or sludge from the treatment works shall pay for such
increased cost." 40 CFR 35.2140.
• "The grantee shall adopt its sewer use ordinance and implement its user charge
system developed under 35.2130 and 35.2140 before the treatment works is
placed in operation. Further, the grantee shall implement the user charge system
and sewer use ordinance for the useful life of the treatment works." 40 CFR
35.2208
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04 Page 12-2
12.3 Wastewater Utility Funds
The City of Yakima's Wastewater Utility operates with four separate funds, as listed and
described in Table 12-1.
Table 12-1
City of Yakima Wastewater Utility Funds
Fund
Description
472
Wastewater Facilities
Capital Reserve Fund
Fund 472 supports major replacement, capital repairs
or minor capital improvements to the wastewater
treatment plant.
473
Wastewater
Operating Fund
Fund 473 contains the system operating, capital
transfer and debt service expenses. The day-to-day
operation expenses of the utility are further classified
into the following service units:
211 - Wastewater Collection System
213 - Surface Drainage (Storm Sewer) Collection
215 - Rudkin Road Pumping Station
232 — Wastewater Treatment Facility
233 — Pretreatment Monitoring Program
476
Collection Systems
Improvements
Fund 476 is utilized for improvements to the collection
system including capital improvements to reduce I/1,
upgrade line capacity, rehabilitate deteriorated pipes,
increase efficiency in operation and maintenance of the
collection system and construct or extend interceptors.
478
Major Treatment
Facility Projects
Fund 478 is the primary source of capital for major
improvements at the Wastewater Treatment Plant.
12.4 Current Revenue Sources
Revenues for operation of the Wastewater Utility are generated from a combination of
rates, connection charges, and pretreatment fees and charges.
12.4.1 Rates
The Wastewater Utilities Division receives revenue from the following five distinct
customer classes in the form of rates established by City Ordinance 2003-_. Specific
rates and charges in place at the time of this Capital Facilities Plan are put forth in
Section 12.7. The five distinct customer classes served by the Wastewater Utility are:
• Owner (inside City) Retail Customers — Residential, commercial, institutional,
governmental and industrial customers within the City of Yakima limits.
• Non -Owner (outside City) Retail Customers — The residential, commercial,
institutional, governmental and industrial connections that are located within
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04 Page 12-3
unincorporated Yakima County, outside the Yakima city limits but within the
Urban Growth area established for the area.
• Septage and Exceptional Discharge Customers — Customers utilizing septic
handling facilities at the Yakima Regional WWTP.
• Municipal Wholesale Customers — Adjacent agencies that the City currently
provides transport, treatment and disposal service to include the City of Union
Gap and Terrace Heights Sewer District.
The City of Yakima reviews wastewater rates bi-annually and following a complete cost
of rate analysis, considers rate adjustments.
12.4.2 Connection Charges
Connection charges are imposed on the owners of any new facilities to be connected to
the existing wastewater system. Connection charges are a capital cost recovery
mechanism used as a means of collecting a fair and equitable share of overall system
improvements that benefit new connections to the system. These charges are determined
and assessed in accordance with state law and the provisions of Chapter 7.58.030 of the
Yakima Municipal Code and the provisions put forth in City Ordinances. Connection
charges consist of three parts: a base treatment plant charge, a base trunk/interceptor
charge and a base collection pipes charge. In that connection charges are determined
based on past and proposed capital expenditures, it is recommended that they be reviewed
and updated at the completion of major improvements to the system and when significant
system analyses and recommended improvement efforts such as this Capital Facilities
Plan are accomplished.
12.4.3 Pretreatment Fees and Charges
Pretreatment fees and charges are assessed to businesses within the City of Yakima
Service Area. Union Gap and Terrace Heights retain responsibility for pretreatment
programs within their respective jurisdictions. Pretreatment fees and charges are
established by City Ordinance 2003-63 to cover costs of testing and monitoring. Strong
waste surcharges may be assessed in addition to these fees.
The City is considering assessing a fee to cover the cost of implementation of a fats, oils
and grease (FOG) control program as means of allocating the cost burden of this element
of the pretreatment program to the appropriate businesses.
12.4.4 Strong Waste Fees and Charges
Customers located within the City of Yakima Service Area discharging wastewater which
contains more than 300 ppm (parts per million) of biochemical oxygen demand (BOD)
and/or total suspended solids (TSS) are charged a strong waste surcharge. The strong
waste surcharge is calculated suing the national average values of BOD and TSS
concentrations typical to each classification under the Standard Industrial Code or by
actual concentrations verified by the City.
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04 Page 12-4
12.5 Components of Wastewater Service Rates
The components of sanitary sewer service charges are generally described as follows:
12.5.1 Wastewater Collection and Maintenance (Service Unit 211)
These expenses include the cost of labor, materials, supplies, chemicals, equipment,
power and other items necessary for operation and maintenance of the wastewater
collection system and small lift stations. These expenses apply to all retail customers
connected to the collection system within the City of Yakima service area.
12.5.2 Surface Drainage Collection Operation and Maintenance (Service
Unit 213)
These expenses include all labor, materials, supplies, equipment, power, and other items
for the operation and maintenance of the City's storm drainage collection and disposal
system and apply only to customers within the City of Yakima.
12.5.3 Rudkin Road Pump Station Operation and Maintenance (Service Unit
215)
Expenses associated the Rudkin Road Pump Station include all required labor, materials,
supplies, equipment, power, and other items for operation and maintenance of the pump
station and are attributable to all customers within the Yakima service area and the City
of Union Gap.
12.5.4 Wastewater Treatment Operation and Maintenance (Service Unit 232)
These expenses include the cost of labor, materials, chemicals, supplies, equipment,
power and other items necessary to operation and maintenance of the Yakima Regional
Wastewater Treatment Plant. Treatment Plant operation and maintenance expenses apply
to customers of the City's wastewater collection, the municipal wholesale customers
(Union Gap and Terrace Heights), and the users of septic handling facilities.
12.5.5 Tax Expense
The revenues of the Wastewater Utilities Division, except revenues received from
wholesale customers, are subject to a State Tax. Gross revenues are also subject to a City
Utility Tax of 14%. By contractual agreement, the City of Union Gap and Terrace
Heights Wastewater District are not assessed the City Utility Tax.
12.5.6 Wastewater Treatment Plant Capital Costs
These expenses include capital costs to the Wastewater Treatment Plant that have a
useful life of more than one year. They include engineering, contract purchases,
administration, labor, supplies, equipment, materials and other items.
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04 Page 12-5
12.5.7 Wastewater Collection System Capital Costs
These capital costs are for improvements to the collection system that have a useful life
of more than one year and include engineering, contract purchases, administration, labor,
supplies, equipment, materials and other items. These costs are applied appropriately to
those customers connected to the collection system within the Yakima service area.
Construction of new interceptors will be financed by the development community with
Limited financial commitment from the City.
12.5.8 Debt Expense
Debt Expense includes debt service on outstanding bonds (both principal and interest) as
well as costs associated with short-term loans used to complete construction projects that
will ultimately be financed by bond funds. Depending on the system components being
financed, all customers may be subject to a potion of debt expense.
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04 Page 12-6
Table 12-2
Components of Sewer Charges
Component
Contributing Customers
Sewer System Collection
Operation & Maintenance
Owner (inside City) Retail
Non -Owner (outside City) Retail
Wastewater Treatment Plant
Operation & Maintenance
Owner (inside City) Retail
Non -Owner (outside City) Retail
City of Union Gap
Terrace Heights Wastewater District
Septage and Exceptional Discharge Customers
Rudkin Road Pumping Station
Owner (inside City) Retail
Non -Owner (outside City) Retail
City of Union Gap
Surface Drainage Collection
Inside City
Tax Expense
Including State and City Utility
Taxes
Owner (inside City) Retail
Non -Owner (outside City) Retail
Septage and Exceptional Discharge Customers
Wastewater Treatment Plant
Capital Costs
Owner (inside City) Retail
Non -Owner (outside City) Retail
City of Union Gap
Terrace Heights Wastewater District
Septage and Exceptional Discharge Customers
Sewer Construction Capital Cost
Owner (inside City) Retail
Non -Owner (outside City) Retail
Wastewater Treatment Plant
Debt Expense
Owner (inside City) Retail
Non -Owner (outside City) Retail
City of Union Gap
Terrace Heights Wastewater District
Septage and Exceptional Discharge Customers
Rehabilitation/Replacement of Sewer
Collection System
Owner (inside City) Retail
Non -Owner (outside City) Retail
New Collection System
Developers
Owner (inside City) Retail (limited initial)
Non -Owner (outside City) Retail (upon
connection)
12.6 Basis of Accounting in Utility Operations
There are two types of accounting used for utility system operations; cash and utility
basis accounting. The cash basis of accounting calculates revenue requirements of the
utility on the basis of cash receipts and outlays as they come due. This method is entirely
cash based and does not include an allowance for depreciation. The primary elements of
cash based accounting are:
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04
Page 12-7
• Operating Expenses — Operating costs include all expenses related to day-to-day
operation and maintenance of the collection system, treatment plant and disposal
facilities, administrative costs and system replacement costs.
• Debt Service — Debt service consists of payments and principal and interest on
both short and long term financing of costs incurred to the system for major
equipment purchases, construction of facilities, obligations to debt -service
reserves, and coverage on bond debt.
• Capital Outlays — Capital outlays consist of system upgrades or improvements to
the wastewater system, or the purchases of equipment paid in cash generated from
revenues or connection fees.
• Taxes — Taxes include all taxes paid to government agencies, such as property
taxes, gross receipt taxes, franchise, or other types of taxes. Taxes are typically
categorized under operating expenses.
The utility basis of accounting calculates revenue requirements using different cost
elements than the cash basis and allows for depreciation and return on investment costs.
The primary elements of utility based accounting are:
• Operating Expenses — Operating costs include all expenses related to day-to-day
operation and maintenance of the collection system, treatment plant and disposal
facilities, administrative costs and system replacement costs.
• Depreciation Costs - The AWWA Manual MI on Water Rates defines
depreciation expense as:"The annual depreciation component of revenue
requirements provides for the recovery of the utility's capital investment over the
anticipated useful life of the depreciable assets. It is, therefore, proper that this
expense be borne by the customers benefiting from the use of these assets ... The
funds resulting from the inclusion of the depreciation expense in the annual
revenue requirement are the property of the utility and are available for use as a
source of capital for replacement, improvement, or expansion of its system, or for
repayment of debt "
• Return on Investment (Rate of Return Allowance) — The rate of return
allowance is defined by the AWWA Mi manual as "The return component is
intended to pay the annual cost of debt capital and provide a fair rate of return
for the total equity capital employed to finance facilities used to provide utility
service."
12.7 Current Wastewater Utility Rates and Charges
Wastewater utility rates are determined and implemented using either the cash or utility
basis of accounting according to the terms and conditions of agreements. Retail water
rates for non -owner customers outside the city limits are established by the utility basis of
accounting. Rates for customers inside the city limits are calculated using the cash basis
of accounting. The City deducts estimated revenues anticipated from retail and septage
customers in the County using the utility basis, subtracts the revenue anticipated from
wholesale municipal customers (Union Gap and Terrace Heights), strong waste
customers and connection charges from the total revenue requirements. The City of
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04
Page 12-8
Yakima's inside city retail customers pay the remaining cash requirements. Direct
service rates and fees are indicated in Tables 12-3 and 12-4.
Wholesale water rates are established in accordance with the terms of the City's contract
with the City of Union Gap and Terrace Heights Sewer District reached in what's
referred to as the "1976 Agreement" and further clarified in the "1997 Settlement
Agreement". These rates are developed using the cash basis of accounting and include
the following elements: Allocation of Treatment plant operation expense based on the
actual impact of each customer on treatment plant operations; Allocation of treatment
plant debt service; Allocation of collection system expenses in proportion to what part of
the system they may use; allocation of collection system capital expenses in proportion to
the allocated capacity of collection system. The City of Union Gap and Terrace Heights
are charged proportionally based on the composition of actual discharges to the plant and
the amount of operation and maintenance expenses attributable to each jurisdiction's
capacity in the treatment facility.
Table 12-3
City of Yakima Wastewater Utility 2004 Monthly Retail Water Rates
Owner
(Inside City)
Retail
Non -Owner
(Outside City)
Retail
All Connections except Multi -family
% inch Water Meter (Minimum)
$13.01
$19.78
1 inch Water Meter
$16.52
$25.12
1 %2 inch Water Meter
$21.34
$32.44
2 inch Water Meter
$34.35
$52.22
3 inch Water Meter
$130.10
$197.80
4 inch Water Meter
$165.62
$251.80
6 inch Water Meter
$248.49
$377.80
8 inch Water Meter
$342.94
$521.40
10 inch Water Meter
$684.89
$1,042.80
Multi Family Customers
Base Charge per Account
$6.77
$10.29
Dwelling Unit Charge per unit
$6.24
$9.49
Volume Charge per 100 cubic feet of water
consumption or discharge quantity metered
$2.28
$3.53
Strong Waste Surcharge
Unit Cost perpound for BOD
$0.312
$0.537
Unit Cost per pound for TSS
$0.286
$0.522
Septage
Unit Cost per Gallon
$0.324
$0.324
Exceptional Waste
Unit Cost per Gallon
$0.324
$0.324
Unit Cost per pound of BOD or TSS
$0.537
$0.537
Unit Cost per pound for TSS
$0.522
$0.522
Unit Cost per 100 cubic feet of wastewater
$0.337
$0.337
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04
Page 12-9
Table 12-4
City of Yakima 2004 Pretreatment Program Rates, Charges and Fees
Charge
Effective
1/1/04
Charge
Effective
1/1/05
Charge
Effective
1/1/06
Monthly Base Fee for Minor Industrial Users
$70.08
$70.91
$73.04
Sampling Period
First Day
$267.90
$275.94
$284.22
Each Subsequent day
in sampling period
$103.73
$106.84
$110.05
Testing Fees
Rates Vary Based on Test performed
Other Related Services
Discharge Authorization lump sum 1
$481.23
$495.66
$510.53
Compliance Inspection per hour
$164.17
$169.10
$174.17
Dye Testing per hour
$164.17
$169.10
$174.17
Smoke Testing per hour
$60.16
$61.97
$63.83
TV (New Construction) per linear foot
$1.93
$1.98
$2.04
TV (Location) per hour
$312.80
$322.18
$331.85
1 Includes only first 50,000 gallons of flow
12.8 Other Methods of Financing
Various other methods of financing are available to wastewater utilities. These
alternatives allow the City to maintain and improve the wastewater system while
maintaining reasonable rates. The appropriate funding method for a given situation
depends on the type of project being financed, its costs, its users and beneficiaries and the
statutory powers of the public agency. This Section summarizes some of the typical
funding options available to the City of Yakima.
12.8.1 Bond Financing
General obligation (GO) bonds are secured by the issuer's power and obligation to levy
property taxes, without limitation as to rate or amount, for the payment of bond service.
GO bonds have traditionally been the least costly form of public borrowing and can be
issued for the entire service area or for a "specific improvement district" that benefits
from the facilities to be financed. Although GO bonds are relatively easy to issue and
administer and typically bear the lowest interest rates, they do require approval of three-
fifths of the voters. Community support is an important consideration in determining
whether or not GO bond financing is appropriate.
Revenue bonds are another widely used method of securing firnding for utility system
projects and are secured by the issuer's ability to generate non -tax revenues. Typically,
revenue bonds are secured with anticipated monthly rate revenues to the utility, but
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04 Page 12-10
connection charges, interest earnings, and other fees and charges can also be considered.
Proceeds from taxes or assessments cannot be used for revenue bonds, and these bonds
technically have no claim on reserves. The bonds' underlying security is that the issuer
commits to operate its system manner that will generate sufficient net revenue, after
payment of operation and maintenance expenses, to meet annual debt service and to
maintain an adequate debt service coverage ratio (typically 1.25 times annual debt
service).
12.8.2 State and Federal Grants and Loans
In the State of Washington there are three primary programs available for fund ng the
type of wastewater facility improvement projects that are recommended in this Plan. The
Centennial Clean Water Fund (CCWF) and the State Revolving Fund (SRF) are
administered by the Washington State Department of Ecology and the Public Works
Trust Fund (PWTF) is administered by the Washington State Department of Trade and
Economic Development. A fourth loan and grant program is administered by the U.S.
Rural Development Association but it is targeted for small agencies less than (10,000
people) and/or unincorporated rural areas.
Local govermnents and Indian tribes are eligible for CCWF loan and grant financing to
support water pollution control facilities and water pollution control activities designed to
prevent and control pollution of the State's ground and surface waters. The CCWF funds
planning, design, acquisition, construction and improvement of water pollution control
facilities and activities. To ensure that funds are distributed fairly, limits have been
placed on the number and size of grants and loans available for each public body in each
fiscal year. Agencies are limited to a maximum of five new funded projects from the
CCWF and Section 319 Fund (Section 319 funding is for water quality improvement
projects such as stream and habitat restoration), two of which may be facility projects.
The total amount of grant and loan assistance from the CCWF cannot exceed $2.5 million
per annual funding cycle and for activity projects, the total amount of grant and loan
assistance can not exceed $250,000 per annual funding cycle. A local match of 50% of
total project costs is required for water pollution control facility grants while a 25% local
match is required for water pollution control activity grants.
The SRF funds high priority projects that protect water quality including wastewater
treatment facilities, non -point source pollution projects, and estuary protection and
preservation programs. Loans are available for up to 100% of total project costs.
The State of Washington Public Works Trust Fund program is considered one of the most
efficient and least expensive methods of financing public works projects in the State of
Washington. Low interest loans are offered for Pre -Construction, Construction, and
Capital Facilities Planning activities.
• Pre -Construction loans arc offered for design, engineering, preparing bid
documents, environmental studies and acquiring rights-of-way for eligible
facilities. A maximum of $1 million per jurisdiction per biennium is offered at an
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04 Page 12-11
interest rate of 0.5% to 2% depending on the loan term and the local match.
Applications are accepted year round and although the program requires a
minimum application score, funds are non-competitive and awarded as available.
• Construction loans are available for projects that repair, replace and improve
public infrastructure systems, including sanitary sewer, domestic water, storm
drainage and road systems. If a preconstruction loan has not been obtained for the
project, these activities can be included in the construction loan application.
Growth is an eligible activity that can be funded by PWTF loans and special
consideration is given to projects in economically distressed areas. Each
jurisdiction is eligible for up to $10 million in financing per biennium for each
jurisdiction. The interest rate is 0.5% to 2% depending on the local match (15%
to 5%). Applications are typically accepted in May of each year and funds are
available in the spring of the following year if the application is successful and
approval is granted by the State Legislature.
• PWTF Capital Facilities Planning loan provides loans to finance capital
facilities plans. A maximum of $50,000 per system is offered at a 0% interest rate
with no local match required. The application cycle is on-going and non-
competitive, although minimum requirements have been established.
• Emergency loans are also available from the PWTF . This type of loan is
intended for public works projects made necessary by a natural disaster, or an
immediate and emergent tlureat to the public health and safety due to unforeseen
or unavoidable circumstances. Loan limit is $500,000 per jurisdiction per year
with a 4% interest rate, 12 month project completion requirement and 20 year
payback. Financial hardship and declaration on emergency are prerequisites to
the program.
12.8.4 Pay -As -You -Go and Capital Reserve Funds
Pay-as-you-go is simply financing capital improvements with cash and, except in times
of high inflation, is the least expensive method of financing. Use of pay-as-you-go
financing, when available, is advantageous for smaller and local improvement projects
and can significantly reduce the overall cost to ratepayers. Larger projects that benefit
both current and future system users are less appropriate for pay-as-you-go financing
because it does not offer the advantage of spreading costs over the life of the project as
debt financing does. Nevertheless, a partial or full pay-as-you-go financing program
allows the utility to accumulate and invest capital reserves. Interest earnings can be a
significant source of income to a long-term capital program and help offset inflation.
Capital reserve funding also utilizes accunulated cash to fund projects and offers the
benefit of eliminating the costs associated with debt financing. Cash generated from
depreciation can be included in monthly rates and set aside in a capital replacement
reserve account available to fund current and future system repairs. In addition, the
additional net revenue required for debt service coverage in one year can be placed in a
reserve account to be used as cash in subsequent years to fund capital improvements. It
is, however prudent to retain some funds in an unrestricted reserve fund that is available
for unforeseen and/or emergency expenditures.
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04
Page 12-12
12.8.5 Development Based Funding
An alternative to new residents paying for service via a connection fee or capital facility
charge is to fund capital costs from developer contributions. Funding options under this
category include Improvement Districts and Special Assessments, In -Lieu -of -Fees, and
Latecomer's Charges. Each of these options provides an opportunity to the City to
receive capacity charges upfront.
12.8.5.1 Improvement Districts and Special Assessments
Projects funded through special assessments must have a special identifiable benefit to
the properties included in the assessment area, and charges for each parcel must be
consistent with the relative benefit to each property. Title 35 of the Revised Code of
Washington (RCW) offers cities the power to establish local improvement districts
(LIDs) or utility local improvement districts (ULIDs) and to levy special assessments on
an annual basis, for up to twenty years against property owners within the identified local
improvement district. In water and wastewater LIDs, the benefit is normally determined
through frontage along the improvement. This option is best for non -regional facilities
that do not benefit the entire area population. A benefit to this method of financing is that
it does not usually impact debt capacity or debt service coverage requirements since the
repayment of the bond or loan is backed by assessments on the property within the
ULID/LID.
12.8.5.2 In -Lieu -of -Construction Fees
In expanding areas, the opportunity for large land developments can provide another
source of capital. In -lieu -of -construction fees can either be a regulatory requirement or a
development option. that enables the City to offer developers the opportunity to construct
on-site facilities in accordance with adopted design criteria or pay a fee that would be
dedicated to the construction and maintenance of facilities serving multiple properties.
This approach has the potential to generate dedicated revenues and to guide development
patterns consistent with the land use comprehensive planning efforts.
In -lieu -of -construction -fees guarantee a new development's initial financing commitment
in program development while enhancing the community's ability to construct and
develop area -wide systems in the most strategic and economic manner. New residents
would be required to pay the same user rates as other properties connected to the system
and upon completion the system would be deeded to the City for ownership and
operation.
12.8.5.3 Latecomer Charges
Latecomer charges are assessed to properties that wish to connect to a portion of the
system that was paid for by local improvement district assessments, by developer
expansion, or by the City in anticipation of increased demand. The latecomer charge
represents the connecting property owners proportionate share of the cost of the facilities
that were previously constructed by someone else. Latecomer charges are generally
determined by simple calculation of the percentage share of the wastewater facility that
City of Yakima Wastewater Facility Plan - DRAFT 6/3/04
Page 12-13
12.8.5.4 Connection Fees
The City of Yakima currently has a connection charge in place for new connections to the
system. As discussed previously in this section, the connection charge has three separate
components: a base treatment plant charge, a base trunk/interceptor charge and a base
collection pipes charge. These charges are levied as a one-time charge assessed against
developers or new customers to recover an equitable share of the value of capacity in the
facilities that are (or will be) available. Connection charges add equity to the system by
requiring new connections to make up -front contributions and allow for growth to pay for
itself in accordance with basic Growth Management Act principals.
12.9 Summary of Recommended Improvements
This Section provides a summary of recommended improvements to the Yakima
Regional WWTP and the collection system identified in previous sections of the Plan.
Improvements have been divided into near term (0-6 years), mid-term (7-12 years) and
long range (13-20 years) recommendations and further broken down into key treatment
features projects, other wastewater treatment facilities projects and collection system
improvements. Project prioritizations were determined based on relative need and
regulatory requirements associated with each.
12.9.1 Wastewater Treatment Plant Improvements
Recommended improvements to the treatment facility include a variety of projects
totaling an estimated $41 million in regulatory, capacity upgrade, health and safety
features and regular renewal and replacement projects over the 20 -year planning horizon
with approximately $17.5 million in improvements scheduled for the 0-6 year near-term
capital improvement program. Wastewater treatment plant improvements are identified
in Table 12-5. Estimated costs, relative schedules and the primary reason for installation
or upgrade are indicated. Indication of the reason for the upgrade should be a primary
determination in deciding the type of funding to be utilized for each project. General
speaking, upgrades that are mandated by regulation are most suitable for loan and grant
financing, while smaller projects and regular renewal and replacements are most
commonly financed from available cash and rates. This does not, however, preclude the
packaging of several related improvements into funding applications that allow similar
projects to be accomplished simultaneously. The inclusion of a variety of projects into
one application also allows the more serious of the issues being addressed to carry less
significant aspects of the overall project tluough competitive processes.
Analysis of the treatment systems performed as part of this facility plan indicates the
need to provide redundancy to several operations within the treatment plant. Redundancy
is required to meet Washington State Department of Ecology criteria for provision of
backup facilities to major treatment processes to assure compliance with the City's
NPDES permit and associated rules and regulations. The following areas have been
identified and prioritized in the planning process as the most critical facilities requiring
redundancy. These projects are included in the Series B bond proceeds ftmding received
in 2003.
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 12-14
• Centrifuge Dewatering (Project 23) — Currently only one of the two centrifuges is
fimctioning for dewatering biosolids and this requires extensive maintenance to
continue operating. A new centrifuge is required to maintain operability and
compliance when the older centrifuge is out of service.
• Solids Thickening (Projects 22) — The waste activated sludge thickening process
reduces the total volume sent to the digestion process, and directly impacts
regulatory compliance. Currently only one dissolved air flotation thickener
(DAFT) unit is in place to thicken secondary sludge. A second thickening unit is
needed to meet redundancy criteria.
• RAS /WAS Pump Station (Project 20) — The RAS/WAS pump station is used to
transport Return Activated Sludge (RAS) from the secondary clarifiers back to the
aeration basin flow control system through two constant speed open screw pumps.
Waste activated sludge is pumped from the two existing secondary clarifiers
through two pumping systems. With the addition of a new secondary clarifier a
new RAS/WAS pumping station will also be required. This facility improvemtn
will resolve existing problems with the RAS pumping flow split and provide
sufficient capacity to handle peak hour flow conditions.
• Standby Power Capacity Addition (Project 38) - The emergency power system
supplies a backup source of power to assure that minimum treatment is provided
during a power failure. The existing generator set was installed in 1980 and at a
minimum, requires a complete inspection/overhaul. An additional generator set is
required to operate the minimum treatment process.
• New Blowers in New Blower Building (Project 7) — Existing VFDs that operate
the four 400 horsepower blowers are far less efficient and generate more
harmonic distortion on the electrical power system than newer technology. They
are all at the end of their useful life, are difficult to find replacement parts for and
require replacement. Construction of a new structure to accommodate new
blowers is recommended.
In addition to redundancy projects the following projects, also scheduled for the 0-6 near
teen planning horizon, have been identified as critical projects for renewal, safety and
efficiency of operations.
• Trickling Filter Door/Walkway Covers (Project 3) — Trickling filter door and
walkway covers have rusted off and should be replaced with non-metallic
materials.
• Aeration Basin Diffusers Rehabilitation (Project 4) — The ceramic diffuser plates
for basins No. 2, No. 3, and No. 4 are 10 years old and need to be replaced with
membrane fine bubble diffusers.
• Upgrade Two Existing Secondary Clarifier Launders for Algae Control and
Improved Access (Project 10) — To alleviate cleaning problems of secondary
clarifier launders due to algae growth, a brush cleaning system or launder covers
should be installed.
• Secondary Clarifier Spray Nozzle Installation (Project 11)
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 12-15
• Primary Sludge Pump Replacement (Project 17) — The air -diaphragm primary
sludge pumps are over 25 years old and should be replaced, possibly with a
different type of pumps without the need for air compressors.
• Replacement of Secondary Scum Pumps and Piping Modification (Project 19) —
The air -diaphragm secondary scum pumps are over 25 years old and should be
replaced. In addition, piping modifications will provide designated suction piping
and valves for pumping of secondary scum and secondary clarifier bottom sludge.
• Centrate Equalization Tankage (Project 25)
• Replacement of Digester Gas Piping, Valves and Flow Meters (Project 27) — The
digester gas collection piping is over 20 years old and needs to be upsized.
• Grease Receiving Facility (Project 30)
• Enclosed Trailer and Cake Storage Facility (Project 33) — Because inclement
weather can interfere with dewatered cake hauling and application operations in
winter, an enclosed trailer and dewatered cake storage facility providing
temporary on-site storage is necessary.
• Laboratory/Instrumentation (Project 35)
• Weather Protection for Odor Control towers (Project 36)
• Odor Control Improvements (Project 37) — Odor control for the Parshall
flumes/primary clarifier influent channels, primary clarifiers, RAS/WAS pump
station, and trickling filter clarifier effluent pump station are needed.
• Replace SCADA System (Project 39) — Major SCADA system components will
be replaced, including PLCs, computer hardware and software, HMI software,
and historical data logging software.
• UV Disinfection (Project 40) — UV disinfection facilities will be installed to
replace chlorine disinfection, reducing safety and security concerns.
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 12-16
Table 12-5
Wastewater Treatment Plant
Recommended Improvement Projects
Project
Number
Facility Description
Opinion of
Probable Cost
0-6
Year
7-12
Year
13-20
Year
Primary Project
Purpose
1
Retrofit Primary Split Box
$428,000
$428,000
Renewal/Safety
2
Replacement of Primary Clarifier Collector Mechanisms
$2,275,000
$2,275,000
Renewal Safety
3
Trickling Filter Door/Walkway Covers
$85,000
$85,000
RenewallSafety
4
Aeration Basin Diffusers Rehab
$50,000
$50,000
Renewal/Safety
5
Structural Repairs to Aeration Basins 1-3 & Internal Anoxic Zone
$1,173,000
$1,173,000
_
Renewal/Growth
6
New Aeration Basin/Anoxic Zone
$2,173,000
$2,173,000
Growth
7
New Blowers in New Blower Building
$1,600,000
$1,600,000
_
Renewal
8
Refurbish Secondary Clarifier Bull -Gears
$130,000
8130,000
Renewal/Safety
9
Replace Secondary Clarifier Skimmer Mechanism/Scum Box
$362,000
$362,000
Renewal/Safety
10
Upgrade Two Existing Secondary Clarifier Launders for Algae
Control and Improved Access
$195,000
$195,000
Renewal/Safety
11
Secondary Clarifier Spray Nozzle Installation
$15,000
$15,000
RenewallSafety
12
New Secondary Clarifier
$3,370,000
$3,370,000
Growth
13
project deleted
-
-
-
14
Retrofit Grit Storage Hopper
$118,000
$118,000
Renewal/Safety
15
Primary Sludge Pumping Density and Flow Meters
$240,000
$240,000
Renewal/Safety
16
Primary Digester Building Lighting Replacement
$49,000
$49,000
Renewal/Safety
17
Primary Sludge Pump Replacement
$100,000
$100,000
Renewal/Safety
18
Raise Intermediate Degritter Center Wall
$250,000
$250,000
RenewallSafety
19
Replacement of Secondary Scum Pumps and Piping Modification
$80,000
$80,000
Renewal/Safety
20
New RAS/WAS Pumping Station for new Secondary Process Units
$1,020,000
$1,020,000
Growth
21
Refurbish DAFT Air Compressors/Pipelines
$65,000
$65,000
RenewallSafety
22
New DAFT Unit
$2,043,000
$2,043,000
Regulatory
23
New Centrifuge and Polymer System
$3,103,000
$3,103,000
Regulatory/Growth
24
New Centrifuge to replace Existing Unit (In 2014)
$1,196,000
$1,196,000
Renewal/Safety
25
Centrate Equalization Tankage
$1,515,000
$1,515,000
Renewal
26
Closure of South Lagoon Without Removal
$111,000
$111,000
Regulatory
27
Replacement of Digester Gas Piping, Valves and Flow Meters
$236,000
$236,000
Renewal/Safety
28
Replacement of Waste Gas Flare
$68,000
$68,000
Renewal/Safety
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05
Page 12 '
Table 12-5
Wastewater Treatment Plant
Recommended Improvement Projects
Project
Number
Facility Description
Opinion of
Probable Cost
0-6
Year
7-12
Year
13-20
Year
Primary Project
Purpose
29
New Boiler/Hot Water
$245,000
$245,000
Growth
30
Grease Receiving Facility
$125,000
$125,000
Regulatory/Safety
31
New Primary Digester
$5,384,000
$5,384,000
Growth
32
Thermophilic Digestion (TPAD)
$5,174,000
$5,174,000
Regulatory
33
Enclosed Trailer and Cake Storage Facility
$1,926,000
$1,926,000
Safety
34
Administration Building Modifications
$500,000
$500,000
Growth
35
Laboratory/Instrumentation
$210,000
$90,000
$85,000
535,000
Renewal/Safety
36
Weather Protection for Odor Control towers
$50,000
$50,000
Renewal/Safety
37
Odor Control Improvements
$1,112,000
$1,112,000
Regulatory/Safety
38
Standby Power Addition to Trickling Filter Pump Station and
Aeration System
$647,000
$647,000
Growth
39
SCADA System Replacement
$930,000
$930,000
Regulatory
40
UV Disinfection
$2,584,000
$2,584,000
Renewal/Safety
Total WWTP Opinion of Probable Costs
$40,937,000
$17,506,000
$15,453,000
$7,978,000
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05
Page 12-18
12.9.2 Collection System Improvements
Note: Analysis and recommendations regarding proposed collection system were
performed by HDR Engineering, Inc. as summarized in the fbllowing paragraphs. A
complete copy of the HDR analysis is contained in the Attachment to Section 11.
Additional project information, along with the below referenced Tables 11-11, 11-13, 11-
14 and 11-15, can be found in the Attachment to Section 11.
The City of Yakima Wastewater Collection system facility needs are discussed and
identified in the Attachment to Section 11 provided earlier in this document. Costs for
improvements have been inflated by 12.8 percent from year 2000 capital project index
basis to year 2004 basis. Analysis of existing facilities to accommodate flows under
build -out conditions indicate that there are several areas where bottlenecks in the system
may create surcharging. The improvement program identified in Table 11-11, at a
probable cost of $694,000 (inflated to $783,000), will provide replacement or parallel
sewers to correct existing system deficiencies and should be completed during the 0-6
year time period. The opinion costs in Table 11-13 represents the anticipated cost of
wastewater collection system improvements necessary to reach build -out conditions
within the Yakima Urban Area with the Rudkin Road bypass alternative. The increase in
cost between the facility improvement to correct existing collection system bottlenecks
(Table 11-11) and the total cost to accommodate build -out flows in the Yakima Urban
Area (Table 11-13) is $1,173,000 (inflated to $1,324,000). As the Yakima Urban Area
reserve is developed, additional interceptor capacity will be needed to transfer these
flows to the Yakima Regional WWTP. All improvements listed in Table 11-13 would be
implemented during the 0-6 year time period. In developing a wastewater collection
system program for ultimate build -out conditions, it is recommended that the City
construct any existing system improvements with sufficient capacity to meet these
requirements.
Additional recommendations for the 0-6 year time period include the development of a
collection system model at a probable cost adjusted to $400,000. The expansion of the
existing shop and administrative facilities at a probable cost of $3,257,600 (inflated to
$3,676,000) is considered to be a priority improvement during the 7-12 year time period.
Table 11-14 identified the opinion of probable cost of future trunk sewers and
interceptors sewers serving the Yakima Urban Area and the Urban Reserve Area. The
total opinion of probable cost for these improvements is shown as $27,111,900 (inflated
to $30,591,400). Zone 2, the Yakima Urban Area, has been assigned 30% of the
Improvement costs. Zone 3, the Yakima Urban Reserve Area has been assigned 70% of
the improvement costs. Approximately 20% of the improvements are expected to be
completed during the 0-6 year time period; 40% during the 7-12 year time period; and,
40% during 13-20 year time period.
The new interceptor serving the Urban Reserve Area will increase flows in the existing
collection system and Table 11-15 identified the opinion of probable cost of
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 12-19
improvements necessary to reach build -out conditions within the Yakima Urban Area and
the Urban Reserve Area at $9,475,000 (inflated to $10,691,000). Of the total opinion of
probable cost in table 11-15, $7,608,000 (inflated to $8,584,000) in increased costs is a
direct result of the increase in service area. The assignment of probable costs to the
Yakima Area (30%) is $2,842,400 (inflated to $3,207,200). The assignment to the
Yakima Urban Reserve Area (70%) is $6,632,600 (inflated to $7,483,800).
The costs of improvements to the collection system are included as separate line items in
Tables 12-6 through 12-8 discussed in Section 12.10.
12.10 Projection of Facility Improvement Financing
The improvements proposed in this Section can be divided into three general categories:
Mandated improvements by federal and state agencies, mandated improvements that are
related to system renewal, safety and/or efficiency and capacity related improvements
related to growth. Mandated projects are those which result from new federal and/or
state regulations. Mandated renewal and replacement projects are the replacement of
existing and worn out (depreciated) facilities to comply with federal or state laws, rules,
regulations and requirements or those projects needed to meet current reliability and
safety standards. Growth related facilities are related to system expansion, system
upgrades, or needed to meet the provisions of the "Four Party Agreement" that are
considered to be mandatory. Table 12-6 identifies the project recommendations for the 0-
6 year time frame, acknowledges the categorization of these projects, and provides
potential sources of financing associated with each project.
In 2003, the City of Yakima implemented a new rate structure to increase revenues to the
wastewater utility. Rate increases are expected to result in total anticipated revenues
from wastewater rates and charges of $12.86 million in 2004 and yield an estimated
increase in net income of $600,000/annually. Additional funding assistance for future
projects comes from the approximate $18 million in parity bonds that were issued by the
City in 2003. These bonds were divided into two distinctive series with approximately
$7.46 million in proceeds from Series A bonds being used to pay for the settlement of
previous litigation relating to odor control within the sewer system. Approximately
$10.61 million in proceeds from sale of Series B Bonds is being used to fund a variety of
projects and capital improvements involving the City's wastewater treatment plant,
including de -watering biosolids, solids thickening, secondary clarification, construction
of a new RAS/WAS pump station, construction of a new emergency power generators
and the replacement of blower and various electronic systems. In addition, proceeds
from the Series B will be used to repay an interfund loan that was made for previous
plant improvements.
Present City policy states that funding for mandatory renewal and replacements should be
from retail rates. Depending on age and condition of facilities and past renewal and
replacement schedules, utilities often find it necessary to fund in excess of the annual
depreciation expense in order to maintain systems at an acceptable level of service and
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 12-20
reliability. The depreciation expense for the Yakima Sewer Utility is estimated at nearly
$2.9 million in 2004.
Projects dedicated to resolving issues related to regulatory requirements arc often
financed by government administered grant and low interest loan financing programs. In
competitive financing programs such as Public Works Trust Fund, Centennial Clean
Water and State Revolving Fund programs, regulation mandated projects tend to receive
higher scores than renewal and replacement or growth driven projects. Growth related
system improvements are generally funded through property assessments, connection
charges and development fees. Although historically federal and state funding sources
have had limited ability to finance growth related projects, the state Public Works Trust
Fund program has expanded to include growth related projects.
Tables 12-6, 12-7 and 12-8 present the recommended projects for the 0-6, 7-12 and 13-20
time frames, respectively, based on whether they are mandate by state and federal
regulations or renewal, safety, operational and efficiency issues; or growth related.
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 12-21
Table 12-6
0 — 6 Year Priority Improvements
Project
Number
Facility Description
Opinion of
Probable Cost
Mandatory 1
2
Growth
Regulatory
Renewal/
Safety
39
SCADA System Replacement
$930,000
$930,000
7
New Blowers in New Blower Building
$1,600,000
$1,600,000
23
New Centrifuge and Polymer System
$3,103,000
$3,103,000
22
New DAFT Unit
$2,043,000
$2,043,000
38
Standby Power Addition to Trickling Filter Pump Station, Aeration
System, and New RAS/WAS Pump Station
$647,000
$647,000
25
Centrate Equalization Tankage
$1,515,000
$1,515,000
4
Aeration Basin Diffusers Rehab
$50,000
$50,000
27
Replacement of Digester Gas Piping, Valves and Flow Meters
$236,000
$236,000
30
Grease Receiving Facility
$125,000
$125,000
35
Laboratory/Instrumentation
$90,000
$90,000
40
UV Disinfection
$2,584,000
$2,584,000
17
Primary Sludge Pump Replacement
$100,000
$100,000
33
Enclosed Trailer and Cake Storage Facility
$1,926,000
$1,926,000
36
Weather Protection for Odor Control towers
$50,000
$50,000
3
Trickling Filter Door/Walkway Covers
$85,000
$85,000
37
Odor Control Improvements
$1,112,000
$556,000
$556,000
19
Replacement of Secondary Scum Pumps and Piping Modification
$80,000
$80,000
20
New RAS/WAS Pumping Station for new Secondary Process Units
$1,020,000
$1,020,000
10
Upgrade two Existing secondary Clarifier Launders for Algae Control
$195,000
$195,000
11
Secondary Clarifier Spray Nozzle Installation
$15,000
$15,000
Subtotal Treatment Facility Improvements
$17,506,000
$9,872,000
$5,967,000
$1,667,000
Collection System Model and Monitoring
$400,000
$400,000
Collection System Facilities (Table 11-11) 3
$783,000
$783,000
Collection Facility Improvements (Table 11-13 & 11-15) 3
$1,324,000
$1,324,000
Collection Facility Improvements (Table 11-14) 20%4
$6,118,000
$1,835,400
$4,282,600
Subtotal Collection Facility Improvements
$8,625,000
$2,235,400
$2,107,000
$4,282,600
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05
Page 12-22
Project
Number
Facility Description
Opinion of
Probable Cost
Mandatory 1
Growth 2
Regulatory
Renewal/
Safety
TOTAL TREATMENT AND COLLECTION
$26,131,000
$12,107,400
$8,074,000
$5,949,600
Compliance with federal/state laws and regulations, and the Four Party Agreement
` System Improvements to accommodate growth related issues.
Table referenced is provided in the Attachment to Section 11 (multiplied by an inflation factor of 1.1283)
Costs shown arc 30% Mandatory, 70% Growth
City ^f Yakima Wastewater Facility Plan - DRAFT 8/12/05 — Dage 12-23
Table 12-7
7 — 12 Year Priority Improvements
Project
Number
Description
Opinion of
Probable Cost
Mandatory 1
2
Growth "
Regulatory
Renewal/
Safety
1
Retrofit Primary Split Box
$428,000
$428,000
2
Replacement of Primary Clarifier Collector Mechanisms
$2,275,000
$2,275,000
5
Structural Repairs to Aeration Basins 1-3
$1,173,000
$750,000
$423,000
8
Refurbish Secondary Clarifier Bull -Gears
$130,000
$130,000
9
Replace Secondary Clarifier Skimmer Mechanism/Scum Box
$362,000
$362,000
12
New Secondary Clarifier
$3,370,000
$3,370,000
14
Retrofit Grit Storage Hopper
$118,000
$118,000
16
Primary Digester Building Lighting Replacement
$49,000
$49,000
21
Refurbish DAFT Air Compressors/Pipelines
$65,000
$65,000
31
New Primary Digester
$5,384,000
$5,384,000
18
Raise Intermediate Degritter Center Wall
$250,000
$250,000
24
New Centrifuge to replace Existing Unit (In 2014)
$1,196,000
$1,196,000
28
Replacement of Waste Gas Flare
$68,000
$68,000
34
Administration Building Modifications
$500,000
$500,000
35
Laboratory/Instrumentation
$85,000
$85,000
Subtotal Treatment Facility Improvements
S15,453,000
$0.00
S5,776,000
$9,677,000
Collection Facilities (Table 11-15 inc. only) 3
$8,584,000
82,575,200
86.008,800
Maintenance Building
$3,676,000
$2,940,800
$735,200
Collection System Facilities (Table 11-14 (40%) 3
812,237,000
$3,671,100
$8,565,900
Subtotal Collection Facility Improvements
$24,497,000
$9,187,100
$15,309,900
TOTAL TREATMENT AND COLLECTION
$39,950,000
$9,187,100
$5,776,000
$24,986,900
1
Compliance with federal/state laws and regulations, and the Four Party Agreement
- System Improvements to accommodate growth related issues.
' Table referenced is provided in the Attachment to Section 11 (multiplied by an inflation factor of 1.1283) - Costs shown are 30% Mandatory, 70% Growth
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05
Page 12-24
Table 12-8
13 — 20 Year Priority Improvements
Project
Number
Facility Description
Opinion of
Probable Cost
Mandatory t
Growth -
Regulatory
Renewal/
Safety
6
Ncw Aeration Basin/Anoxic Zone
$2,173,000
$2,173,000
15
Primary Sludge Pumping Density and Flow Meters
$240,000
$240,000
26
Closure of South Lagoon Without Removal
$111,000
$111,000
29
New Boiler/Hot Water
$245,000
$245,000
32
Thermophilic Digestion (TPAD)
$5,174,000
$5,174,000
35
Laboratory/Instrumentation
$35,000
$35,000
Subtotal WWTP Opinion of Probable Costs
$7,978,000
$5,285,000
$275,000
$2,418,000
Collection Facility Improvements (Table 11-14) 40%'
$12,237,000
$3,671,100
$8,565,900
Subtotal Collection Facility Improvements
$12,237,000
$3,671,100
$8,565,900
TOTAL TREATMENT AND COLLECTION
$20,215,000
$8,956,100
$275,000
$10,983,900
1
Compliance with federal/state laws and regulations, and the Four Party Agreement
System Improvements to accommodate growth related issues.
' Table referenced is provided in the Attachment to Section 11 (multiplied by an inflation factor of 1.1283) - Costs shown are 30% Mandatory, 70% Growth
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05
Page 12-25
Table 12-8A shows the percentages of costs for Mandatory and Growth related projects.
As indicated in the table the greater percentage of costs for the Wastewater treatment
plant are mandatory whereas the greater percentage of costs for the collection system are
growth related. Total Treatment and collection costs are equally divided between
mandatory and growth related improvements.
Table 12-8A
% of Total Costs by Primary Project Purpose
Treatment and Collection
Project costs
Mandatory 1
Growth 2
Regulatory
Renewal/
Safety
Total WWTP Opinion of Probable Costs
S40,937,000
$15,157,000
$12,018,000
$13,762,000
66%
34%
Total Collection Facility Improvements
$45,359,000
$15,093,600
$2,107,000
$28,158,400
38%
62%
TOTAL TREATMENT AND COLLECTION
$86,296,000
$30,250,600
$14,125,000
S41,920,400
51%
49%
Compliance with federal/state laws and regulations, and the Four Party Agreement
2 System Improvements to accommodate growth related issues.
12.11 Annual Operation and Maintenance
This section provides a summary of mandatory and recommended operation and
maintenance costs for the wastewater facilities of the Yakima Regional Wastewater
Treatment Plant and City of Yakima Wastewater Collections System.
12.11.1 Wastewater Treatment Program
The Yakima Regional Wastewater Treatment Program staffing and equipment needs will
not be significantly increased as a result of improvements identified in this Plan. The
existing treatment process systems will be increased in size to accomodate wastewater
flows as population increases throughout the service area. As new equipment and
increased treatment capacity is added, additional staffing may be required. Table 12-9
provides a summary of treatment plant operation and maintenance costs.
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 12-26
Table 12-9
Wastewater Treatment Staffing/Program Costs
Category
Full time Equivalents
Annual Cost
Facility Management
5.75
$400,000
Facility Operations
19.58
$1,133,000
Facility Maintenance
8
$467,000
Facility Laboratory
5
$277,000
Engineering Support
2
$142,000
Power/Water/Refuse/Chemicals
$450,000
Machinery/Equipment
$150,000
City Services/Ancillary
$1,600,000
Estimated Annual Program Cost
$4,619,000
12.11.2 Pretreatment/Strong Waste Program
The City's pretreatment and strong waste programs are identified in Section 6. Table 12-
10 provides a summary of the estimated staffing and monetary requirements for
maintaining these programs. Additional staffing may be required in conjunction with
system expansion and growth.
Table 12-10
Pre -Treatment Strong Waste Staffing/Program Costs
Category
Full time Equivalents
Annual Cost
Pretreatment Management
1.85
$143,000
Pretreatment Staff
6
$358,000
Operating Supplies
$170,000
Machinery/Equipment
$100,000
Estimated Annual Pretreatment/Strong Waste Program Cost
$771,000
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 12-27
12.11.3 Collection System Program
The City of Yakima Wastewater Collection System operation and maintenance needs are
summarized below in Table 12-11,
Table 12-11
Collection System Staffing/Program Costs
Category
Full time
Equivalents
Annual Cost
Collection System Management
2.4
$187,000
Collection System Maintenance
18
$983,000
City Services/Ancillary
$300,000
Operating Supplies
$400,000
Machinery/Equipment
$850,000
Estimated Annual Wastewater Collection Staffing/Program
$2,720,000
12.12 Projected Budget and Recommendations
Table 12-12 presents a historical and projected budget for the City of Yakima
Wastewater Utility. This simplified budget overview is intended to provide order of
magnitude costs and assist the City in its on-going decision making, project prioritization
and budgeting. More detailed consideration of available funds and revenue requirements
occurs bi-annually in the City's established rate review and cost -of -service analysis and
periodic review and adjustment of connections charges. As indicated in Table 12-12 and
discussed previously in this Section, the 2003 bond issue provides a significant source of
revenue for immediate improvements to the wastewater treatment plant. Long term
financing strategies will include continuing to apply for grant and low interest funding,
where appropriate, and maintaining current and equitable connection charges and fees so
that growth can finance required system expansions.
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 12-28
Operating Revenues
Operating Expenses
Operating Expense
Depreciation Expense
In -lieu Tax
Other Taxes
Total Operating Expenses
Net Operating Income
Table 12-12
Projected Wastewater Utility Budget
Actual 2002 Estimated 2003 Budget 2004 2005
$11,061,537 811,568,180 $12,862,248 $12,926,559
$5,989,079
$2,725,912
$1,322,373
$536,125
$10,573,489
$488,048
$5,997,500 $6,538,711 $6,669,485
$2,951,613 $2,866,686 $2,671,651
$1,401,362 $1,589,145 $1,620,928
$629,872 $648,758 $661,733
$10,980,347 $11,643,300 $11,623,797
2006 2007
$12,991,192 $13,445,884
$6,836,222 $7,041,309
$3,079,581 $3,412,512
$1,661,451 $1,711,295
$678,276 $698,625
$12,255,531 $12,863,740
$587,833 $1,218,948 $1,302,762 $735,661 $582,143
Other Income
Gain (Loss) on Sale of Assets 80 $0 $0 $0 $0 $0
Interest Income/(Expense) net(4) ($233,978) ($40,819) ($37,992) ($14,942) $10,058 $35,058
Non-utility Income(5) $15,625 $301,496 $320,064 $407,064 $407,064 $407,064
Miscellaneous $0 $0 $0 $0 $0 $0
Total Other Income ($218,353) $417,122 $442,122
Total Income $269,695 $1,152,783 $1,024,265
$260,677
$848,510
$282,072 $392,122
$1,501,020 $1,694,884
Available for Debt Service
on First Lien Bonds (1) $4,317,980 $5,201,485 $5,956,851 $5,987,463 $5,893,815 $6,148,072
First Lien Debt Service $273,653 $276,075 $0 $0 $0 l
Coverage 15.78 18.84 n/a n/a n/a n/a `
Available for Debt Service
on Second Lien Bonds (2) $4,044,327 $4,925,410 $5,956,851 $5,987,463 $5,893,815 $6,148,072
Second Lien Debt Servicc(3)
SRF Loan $324,791 $162,396 $0 $0 $0 $0
1996 Bonds $363,875 $361,915 $369,360 $365,585 $366,035 $370,285
1991-1998 ref $609,647 $505,052 $504,868 $508,722 $507,254 $500,253
1998 new $0 $0 $0 $0 $0 $0
2003 Bonds $0 $0 $1,292,472 $1,352,030 $1,349,430 $1,349,180
Coverage
$1,298,313 $1,029,363
3.12 4.78
$2,166,700 $2,226,337
2.75 2.69
$2,222,719 $2,219,718
2.65 2.77
(1) Net Revenues as defined in the Bond Ordinance.
(2) Net Revenues less First Lien debt service.
(3) Excludes Public Works Trust Fund Loans.
(4) Includes interest expense on PWTF Loan but not parity debt interest.
(5) Represents operating contribution for debt service from Union Gap and Terrace Heights.
Notes:
All Operating expenses except depreciation (depreciation includes new projects as disclosed herein) are increased 2.0% for 2005, 2.5%
for 2006, and 3.0% for 2007.
Operating revenues are increased .5% for 2005 and 2006, 3.5% for 2007
Interest is increased $23,050 for 2005 and for 2006and 2007 $25,000
Source: City of Yakima
City of Yakima Wastewater Facility Plan - DRAFT 8/12/05 Page 12-29
Page 1 of 46
Permit No.: WA -002402-3
Issuance Date; April 30, 2003
Effective Date: June 1, 2003
Expiration Date: May 31, 2008
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
WASTE DISCHARGE PERMIT NO. WA -002402-3
STATE OF WASHINGTON
DEPARTMENT OF ECOLOGY
YAKIMA, WASHINGTON 98902
In compliance with the provisions of
The State of Washington Water Pollution Control Law
Chapter 90.48 Revised Code of Washington •
and
The Federal Water Pollution Control Act
(The Clean Water Act)
Title 33 United States Code, Section 1251 et seq.
City of Yakima Publicly -Owned Treatment Works
129 N. 2nd Street
Yakima, WA 98901
is authorized to discharge in accordance with the special and general conditions that follow.
Treatment Plant Location:
2220 E. Viola Avenue
Yakima, WA 98901
Water Body I.D. No.:
WA -37-1040
Treatment Processes:
Activated sludge with primary and secondary clarifiers, trickling filters, and chlorine disinfection
with dechlorination.
Receiving Water:
Yakima River, River Mile 110.1
Discharge Location:
Latitude: 46° 34' 48" N
Longitude: 120° 27' 52" W
. Thomas Tebb, L E.G.
ction Manager
Central Regional Office
Water Quality Program
Washington State Department of Ecology
Page 2 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
TABLE OF CONTENTS
Page
SUMMARY OF PERMIT REPORT SUBMITTALS 5
SPECIAL CONDITIONS 7
,
S1. DISCHARGE LIMITATIONS 7
A. Effluent Limitations 7
B. Mixing Zone Descriptions 9
S2. MONITORING REQUIREMENTS g
A. Monitoring Schedule 9
B. Sampling and Analytical Procedures 12
C. Flow Measurement 12
D. Laboratory Accreditation 12
E. Request for Reduction of Monitoring 12
S3. REPORTING AND RECORDICEEPING REQUIREMENTS 13
A. Reporting 13
B. Records Retention 14
C. Recording of Results 14
D. Additional Monitoring by the Permittee 14
E. Noncompliance Notification 14
S4. FACILITY LOADING 15
A. Design Criteria 15
B. Plans for Maintaining Adequate Capacity 15
C. Duty to Mitigate 16
D. Notification of New or Altered Sources 16
E. Infiltration and Inflow Evaluation 17
F. Wasteload Assessment 17
S5. OPERATION AND MAINTENANCE (O&M) 17
A. Certified Operator 18
B. O&MProgram 18
C. Short-term Reduction 1 8
D. Electrical Power Failure 18
E. Prevent Connection of Inflow 18
F. Bypass Procedures 19
G. O&M Manual 21
S6. PRETREATMENT 21
Page 3 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
A. General Requirements 21
B. Monitoring Requirements 25
C. Reporting of Monitoring Results 27
D. Local Limit Development 27
S7. RESIDUAL SOLIDS 27
S8. ACUTE TOXICITY 28
A. Acute Rapid Screening Testing 28
B. Sampling and Reporting Requirements 28
S9. CHRONIC TQXICITY 30
A. Effluent Limit for Chronic Toxicity 30
B. Monitoring for Compliance With an Effluent Limit for Chronic Toxicity 30
C. Response to Noncompliance With an Effluent Limit for Chronic Toxicity 31
D. Sampling and Reporting Requirements 32
S10. RECEIVING WATER AND EFFLUENT STUDY 33
A. Effluent Analysis 33
B. Receiving Water Analysis 34
C. Quality Assurance Project Plan (QAPP) 35
S11. FACILITY PLAN 35
A. Final Facility Plan 35
S12. OUTFALL EVALUATION 36
S13. SCHEDULE OF COMPLIANCE 36
A. Scope of Work Report 37
B. Metals Study 37
C. Assessment Report 37
D. Water -Effects Ratio Study 37
E. Engineering Report 38
GENERAL CONDITIONS 39
G1. SIGNATORY REQUIREMENTS 39
G2. RIGHT OF INSPECTION AND ENTRY 40
G3. PERMIT ACTIONS 40
G4. REPORTING A CAUSE FOR MODIFICATION 41
Page 4 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
G5. PLAN REVIEW REQUIRED 42
G6. COMPLIANCE WITH OTHER LAWS AND STATUTES 42
G7. DUTY TO REAPPLY 42
G8. TRANSFER OF THIS PERMIT 42
G9. REDUCED PRODUCTION FOR COMPLIANCE 43
G10. REMOVED SUBSTANCES 43
G11. DUTY TO PROVIDE INFORMATION 43
G12. OTHER REQUIREMENTS OF 40 CFR 43
G13. ADDITIONAL MONITORING 43
G14. PAYMENT OF FEES 44
G15. PENALTIES FOR VIOLATING PERMIT CONDITIONS 44
G16. UPSET 44
G17. PROPERTY RIGHTS 45
G18. DUTY TO COMPLY 45
G19. TOXIC POLLUTANTS 45
G20. PENALTIES FOR TAMPERING 45
G21. REPORTING PLANNED CHANGES 45
G22. •REPORTING ANTICIPATED NON-COMPLIANCE 46
G23. REPORTING OTHER INFORMATION 46
G24. COMPLIANCE SCHEDULES 46
Page 5 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
• SUMMARY OF PERMIT REPORT SUBMITTALS
Refer to the Special and General Conditions of this permit for additional submittal
requirements.
Permit
Section
Submittal
Frequency .
First
i Submittal Date
S2.E.
Request for Reduction of Monitoring
As necessary
As necessary
S3.A.
Discharge Monitoring Report
Monthly
July 15, 2003
S3.E.
Noncompliance Notification
As necessary
As necessary
S4.B.
Plans for Maintaining Adequate
Capacity
As necessary
As necessary
S4.D.
Notification of New or Altered Sources
As necessary
As necessary
S4.E.3
Infiltration and Inflow Evaluation
Annually
January 15, 2004
.S4.F.
Wasteload Assessment.
2/permit cycle
January 15, 2004
(Within Facility Plan)
85.G.
Operations and Maintenance Manual
1/permit cycle
May 31, 2007a
S6.A.2.
Accidental Spill Plan •
1/permit cycle
January 15, 2004
S6.A.5.
Pretreatment Report
Annually
April 15, 2004
S8.B.9.
Acute Toxicity Compliance Monitoring
Reports
•
As necessary
Within sixty (60) days
after each subsequent
sampling event)
S8.B.10.
Acute WET Testing Summary Report
1/permit cycle
May 31, 2007a
S9.B.
Chronic Toxicity Compliance
Monitoring Reports
.
As necessary
Within sixty (60) days
after each subsequent
sampling event
S9.C.
Chronic Toxicity TI/TRE Plan
As necessary
As necessary
S9.D.9.
Chronic WET Testing Summary Report
1/permit cycle
May 31, 2007a
81.0.
Receiving Water and Effluent Study
Results
1/permit cycle
May 31, 2007a
S10.C.
Receiving Water and Effluent Study
Sampling and Quality Assurance Plan
1/permit cycle
October 1, 2003
S11. A.
Facility Plan
1/permit cycle
January 1, 2004
S12.
Outfall Evaluation
1/permit cycle
January 15, 2005
S13.A.
Schedule of Compliance -Scope of Work
1/permit cycle
January 1, 2004
S13.C.
Schedule of Compliance -Assessment
Report
1/permit cycle
July 15, 2006
S13.D.
Schedule of Compliance -Water Effects
Ratio Study Plan
As necessary
With Assessment
Report
S 13.E.
Schedule of Compliance -Engineering
Report •
As necessary
May 31, 2007a
01.
Notice of Change in Authorization
As necessary
As necessary
Page 6 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
Permit
Section
Submittal
Frequency
First
Submittal Date
04.
Permit Application for Substantive
Changes to the Discharge
As necessary
As necessary
G5.
Engineering Report for Construction or
Modification Activities
As necessary
As necessary
G7.
Application for Permit Renewal
1/permit cycle
May 31, 2007b
G21.
Notice of Planned Changes
As necessary
As necessary
G22.
Reporting Anticipated Non-compliance
As necessary
As necessary
a With applicafion for permit renewal
b .At least one (1) year prior to permit expiration
r
Page 7 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
SPECIAL CONDITIONS
Si. DISCHARGE LIMITATIONS
A. Effluent Limitations
All discharges. and activities authorized by this permit shall be consistent with the •
terms and conditions of this permit. The discharge of any of the following
pollutants more frequently than, or at a level in excess of; that identified and
authorized by this permit shall constitute a violation of the terms and conditions
of this permit. In addition, the Permittee shall comply with the requirements of
the Schedule of Compliance in Special Condition S13.
1. Interim Limitations
Beginning on the June 1, 2003 and lasting through January 15, 2008, the
Permittee is authorized to discharge treated municipal wastewater to the
Yakima River at the permitted location subject to the following
limitations: •
EFFLUENT LIMITATIONS': OUTFALL # 001
Parameter
Average Monthlyb
Average Weekly
5 -day Biochemical Oxygen
Demand (BODS)
' . 30 mg/L
. .85% removal
45 mg/L.
.
Total Suspended Solids (TSS)
30 mg/L
85% removal
45 g/L
Fecal Coliform Bacteria
200 colonies/100 mL
colonies/100 mL
pHe
Between 6.0 and
at all times.
Parameter "
Average Monthly /
Maximum Dail?
Total Residual Chlorine (TRC)
:. i m
0.029 mg/L
Total Ammonia, as N
4.6 mg�i
12.3 mg/L
Total Copper
9.84 µg/L
14.36 µg/L
Total Lead
.' : • • _
5.77 µg/L
Total Silver
• 2.18 µg/L•
3.17 µg/L
Total Zinc
70.35 µg/L
95.82 µg/L .
Chronic WET Limit
.
The chronic toxicity limit shall be no statistically significant
difference in test organism response between the chronic
critical effluent concentration (CCEC), 15.1% of the effluent,
and the control. (See Special Condition S9. for further
information.)
a -The average monthly and weekly effluent limitations are based on. the arithmetic mean of the
samples taken with the exception of fecal coliform, which is based on the geometric mean,
b -The average monthly effluent concentrations for BOD and TSS shall not exceed 30 mg/L or
15 percent of the respective monthly average influent concentrations.
Page 8 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
c -Indicates the range of permitted values.
d -The maximum daily effluent limitation is defined as the highest allowable daily discharge.
The daily discharge means the discharge of a pollutant measured during a calendar day. For
pollutants with limitations expressed in units of mass, the daily discharge is calculated as the
total mass of the pollutant discharged over the day. For other units of measurement, the daily
discharge is the average measurement of the pollutant over the day.
2. Final Limitations
Beginning on January 16, 2008 and lasting through the May 31, 2008,
the Permittee is authorized to discharge treated municipal wastewater to
the Yakima River at the permitted location subject to the following
limitations:
EFFLUENT LIMITATIONS": OUTFALL # 001
Parameter
Average Monthly`
Average W.eeldy
BOD5
.
30 mg/L
85% removal
45 mg/L
TSS
30 mg/L •
85% removal
45 mg/L
Fecal Coliform Bacteria
200 colonies/100mL -
400 colonies/100 mL
pH
-Between 6.0 and 9.0 at all times.
Parameter
Average Monthly
Maximum Daily
--TRC
0.012 mg/L
0.029 mg/L
Total Ammonia, as N
.4.6 mg/L
12.3 ing/L
Total Copper
6.71 p.g/L
9.80 µg/L
Total Lead -
3.96 p.g/L
5.77 pg/L
Total Silver
2.18 p.g/L
µg/L
Total Zinc
45.70 ug/L
.3.17
6630 p.g/L
Chronic WET Limit
No statistically significant difference in test organism response
between the chronic critical effluent concentration (CCEC),
15.1% of the effluent, and the control. (See Special Condition
S9. for further information.)
a -The average monthly and weekly effluent limitations are based on the arithmetic mean of the
samples taken with the exception of fecal coliform, which is based on the geometric mean. .
b -Effluent limits may be revised through a permit modification after approval of the Final
Facility Plan.
c -The average monthly effluent concentrations for BOD and TSS shall not exceed 30 mg/L or
15 percent of the respective monthly average influent concentrations. .
d -The maximum daily effluent limitation is defined as the highest allowable daily discharge.
The daily discharge means the discharge of a pollutant measured during a calendar day. The
daily discharge is the average measurement of the pollutant over the day.
Page 9 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
13. Mixing Zone Descriptions
The authorized mixing zones are defined as follows:
The length of the chronic and acute mixing zones shall extend downstream no
greater than 310 feet and 31 feet, respectively. The width of the chronic and acute
mixing zones shall be no more than 50 feet wide. The aquatic life -based dilution
factors foi the chronic and acute mixing zones were determined to be 6.61 and
1.51, respectively.
S2. MONITORING REQUIREMENTS
A. Monitoring Schedule
Category
Parameter
Units
Sample
Point
Minimum
Sampling
Frequency
Sample
Type
Domestic
Influent
Wastewatera
BOD5
mg/L
Headworks
3/week"
24-hour
Composite°
"
BOD5
lbs/day
Calculations
"
TSS
mg/L
24-hour
Composite
"
TSS
lbs/day
Calculation
"
TKN
mg/L
1/monthe
24-hour
Composite
..TKN.
lbs/day
Calculation
..Flow
MGD
,,
Continuous!
Metered
Industrial
Influent
Wastewaters
BOD5
mg/L
•
Del Monte"
3/week •24-hour
•
• Composite
..BODS
lbs/day
"
"
Calculation
"
.TSS
mg/L
..
•
24-hour
Composite
"
TSS
lbs/day
Calculation
"
TKN
mg/L
1/month
24-hour
Composite
..TKN
lbs/day
Calculation
..Flow
MGD
Continuous
Metered
Page 10 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
Category
Parameter
Units .
.Sample
Point .
Minimum
Sampling
Frequency
Sample
Type
Totalln.fluent
Loadings'
BODS
lbs/day
Not
Applicable
3/week
Calculation
• TSS
lbs/day
."
it
Calculation
"
• TKN
lbs/day
it
1/month.
Calculation
it•
---- -=- ----------
Flow
.•MGD
Continuous
Metered
Effluent
Wastewater
BODS
• mg/L.
After
Dechlorination
3/week
24-hour
Composite
"
BOD5
lbs/day"
3/week
Calculation
it
BOD5
% removal
it
_
3/week
Calculation'
it
'
TSS
mg/L
" •
3/week
24-hour
Composite
"
TSS
lbs/day .
- it
3lweek
Calculation
"
TSS
% removal •
•
3/week
Calculation
ii
TRC,
• mg/L
. It
3/week
Grab'`
II
TRC
lbs/day
3/week
Calculation
11
Sulfites
mg/L
it
'3/week
Grab
"
Sulfites
' lbs/day -
it
3/week
Calculation
"
Fecal
Coliform
Bacteria
#colonies/11
100 mL
.
3/week •
Grab
"
NH3, as N
mg/Lit
3/week
•
24-hour
Composite
ti
NH3, as N
lbs/day
ti
3/week
Calculation
"
DO
mg/L
3/week
Grab
"
Temperature
°C
113/week
Grab
"
pH
Standardit
Units
3/week
Grab
"
Alkalinity
.
mg/L, asii
CaCO3
1/month
Grab
"
Hardness
mg/L, asit
CaCO3
1/month
Grab
"
Total Copper
pg/L
1/month '
Grab'
"
Total Lead
µg/L
ii
1/month
Grab'
"
Total Silver
_ pg/L
ti
1/month
Grab'
"
Total Zinc
I -La
it
1/month
Grab'
±- if•tj-_-
t-iF-
11.,-
v-f,z-__ r�_���_�-� __+--...-y
--
_ _
ate£-?iA��L.-£i._�-_ ...�'�-c -- —
irk
Page 11 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
Category.
.
Parameter
Units
Sample
Point
Minimum
Sampling
. Frequency
Sample
Type
Pretreatment
As specified in Special Condition S6.
Sludge
As specified in Special Condition S6.B. • •
moi_'=
-- -_-_�s�=--'-T_`T^'-- _------_i.r._ _ _.-.r;IT-..-_. __-,i-'r'�L
AcuteAs
Toxicity
Testing .
specified in Special Condition S8.
.
ChronicAs
Toxicity
Testing
__ T __
specified in Special Condition S9. .
Receiving
Water and
Effluent
Study.
As specified in Special Condition S10.
-
_
Ground Water
. As specified in Appendix C of the approved O&M Manual.
a "Domestic Wastewater Influent" means the raw sewage flow entering the headworks of the treatment plant,
excluding any sidestream returns from inside the plant. - _
b "3/week" means three (3) times during each calendar week and on a rotational basis throughout the days of the
week.
c "24-hour composite" mean's a series of at least four (4) individual samples collected'over a 24-hour period into a
single container, and analyzed as one sample. -
d "Calculation" of mass loading means figured concurrently with the respective sample using the following formula:
Concentration (in mg/L).X Flow (in MGD) X Conversion Factor (8.34) = lbs/day.
e "1/month" means once every calendar month, including weekends and holidays, and on a rotational basis
throughout the weeks of the month. Samples shall not be taken during the same calendar week.
f "Continuous" means without interruption throughout the operating and discharging hours of the Permittee's facility,
except for infrequent shutdowns for maintenance.
g "Industrial Wastewater Influent" means wastewater entering the treatment plant from the Industrial Waste
collection system. Monitoring of Industrial Waste wastewater shall occur whenever Del Monte is discharging.
h The sampling point for influent entering the treatment plant from the Industrial Waste collection system shall be at
Del Monte discharge point to the public sewer.
i "Total Influent Loadings" means the aggregate loadings to the treatment plant from the sanitary and Industrial
Waste collections systems.
j BOD and TSS percent (%) removal shall be calculated using the following algorithm:
(Average Monthly Influent Concentration (in mg/L) = Average Monthly Effluent Concentration (in mg/L))/Average
Monthly Influent Concentration (in mg/L)
k "Grab" means an individual sample collected over a fifteen (15) minute, or less, period.
1 Sampling and analysis for Copper, Lead, Silver and Zinc shall be conducted utilizing the Clean Sampling methods
specified in Special Condition S10.B.
Page 12 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
B. Sampling and Analytical Procedures
Samples and measurements taken to meet the requirements of this permit shall be
representative of the volume and nature of the monitored parameters, including
representative sampling of any unusual discharge or discharge condition,
including bypasses, upsets and maintenance -related conditions affecting effluent
quality.
Sampling and analytical methods used to meet the monitoring requirements
specified in this permit shall conform to the latest revision of the Guidelines
Establishing Test Procedures for the Analysis of Pollutants contained in 40 CFR
Part 136 or to the latest revision of Standard Methods for the Examination of
Water and Wastewater (APHA), unless otherwise specified in this permit or
approved in writing by the Department of Ecology (Department).
C. Flow Measurement
Appropriate flow measurement devices and methods consistent with accepted
scientific practices shall be selected and used to ensure the accuracy and
reliability of measurements of the quantity of monitored flows. The devices shall
be installed, calibrated, and maintained to ensure that the accuracy of the
measurements are consistent with the acceptedindustry standard for that type of
device. Frequency of calibration shall be in conformance with manufacturer's
recommendations. Calibration recordsshall be maintained for at least three years.
D. Laboratory Accreditation
All monitoring data required by the Department shall be prepared by a laboratory
registered or accredited under the provisions of, Accreditation of Environmental
Laboratories, Chapter 173-50 WAC. Flow, temperature, settleable solids,
conductivity, pH, and internal process control parameters are exempt from this
requirement. Conductivity and pH shall be accredited if the laboratory must
otherwise be registered or accredited. The Department exempts crops, soils, and
hazardous.waste data from this requirement pending accreditation of laboratories
for analysis of these.media.
E. Request for Reduction of Monitoring
The Permittee may request a reduction of the sampling frequency after twelve
(12) months of monitoring. The request shall: (1) be' in written form, (2) clearly
state the parameters for which the reduction in monitoring is being requested, and
Page 13 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
(3) clearly state the justification for the reduction. Any request for reduction in
monitoring shall be granted at the Department of Ecology's (Department)
discretion and accomplished through an Administrative Order or permit
modification.
S3. REPORTING AND RECORDKEEPING REQUIREMENTS
The Permittee shall monitor and report in accordance with the following conditions. The
falsification of infonnation submitted to the Department shall constitute a violation of the
terms and conditions of this permit.
A. Reporting
The first monitoring period begins on the effective date of the permit. Monitoring
results shall be submitted monthly. Monitoring data obtained during each
monitoring period shall be summarized, reported, and submitted on. a Discharge
Monitoring Report (DMR) form provided, or otherwise approved, by the
Department. DMR fors shall be received by the Department no later than the
15th day of the month following the completed monitoring period, unless
otherwise specified in this permit. Priority pollutant analysis data shall be
submitted no later than sixty (60) days following the monitoring period. The
report(s) shall be sent to:
Permit Data Systems Coordinator
Department of Ecology
Central Regional Office
15 West Yakima Avenue, Suite 200
Yakima, Washington 98902
All laboratory reports providing data for organic and metal parameters shall
include the following information: sampling date, sample location, date of
analysis, parameter name, analytical method/number, method detection limit
(MDL), laboratory quantitation limit (QL), reporting units, and concentration
detected.
In addition to the monthly DMR to the Department, a monthly summary report
form (EPA No. 3320-1) shall be received by EPA no later than the 15th day of the
following month..
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
B. Records Retention
The Permittee shall retain records of all monitoring information for a minimum of
three (3) years. Such information shall include all calibration and maintenance
records and all original recordings for continuous monitoring instrumentation,
copies of all reports required by this permit, and records of all data used to
complete the application for this permit. This period of retention shall be
extended during the course of any unresolved litigation regarding the discharge of
pollutants by the Permittee or when requested by the Department.
C. Recording of Results
For each measurement or sample taken, the Permittee shall record the following
information: (1) the date, exact place, method, and time of sampling or
measurement; (2) the individual who performed the sampling or measurement; (3)
the dates the analyses were performed; (4) the individual°who performed the
analyses; (5) the analytical techniques or methods used; and (6) the results of all
analyses.
D. Additional Monitoring by the Permittee
If the Permittee monitors any pollutant more frequently than required by this
permit using test procedures specified by Special Condition S2 of this permit,
then the results of such monitoring shall be included in the calculation and
reporting of the data submitted in the Permittee's DMR.
E. Noncompliance Notification
In the event the Permittee is unable to comply with any of the terms and
conditions of this permit due to any cause, the Permittee shall:
1. Immediately take action to stop, contain, and cleanup unauthorized
discharges or otherwise stop.the noncompliance, correct the problem and, if
applicable, repeat sampling and analysis of any noncompliance immediately
and submit the results to the Department within thirty (30) days after
becoming aware of the violation.
2. Immediately notify the Department of the failure to comply.
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Expiration Date: May 31, 2008
3. Submit a detailed written report to the Department within thirty (30) days
(five [5] days for upsets and bypasses), unless requested earlier by the
Department. The report shall contain a description of the noncompliance,
including exact dates and times, and if the noncompliance has not been
corrected, the anticipated time it is expected to continue; and steps taken or
planned to reduce, eliminate, and prevent reoccurrence of the noncompliance.
Compliance with these requirements does not relieve the Permittee from
responsibility to maintain continuous compliance with the terms and conditions of
this permit or the resulting liability for failure to comply.
S4. FACILITY LOADING
A. Design. Criteria
Flows or waste loadings of the following design criteria for the permitted
treatment facility shall not be exceeded:
Parameter
Design Criteria
Average flow (max. month)
TBDa
BODS loading (max. month)
TBD
TSS loading (max. month)
TBD
Design pppulation
TBD ;
a -Design criteria shall be incorporated from the approved Facility Plan into this
permit through a permit modification.
B. Plans for Maintaining Adequate Capacity
When the actual flow or waste load reaches eighty-five (85) percent of any one of
the design criteria in the approved Facility Plan for three (3) consecutive months,
or when the projected increases would reach design capacity within five (5) years,
whichever occurs first, the Permittee shall submit to the Department, a plan and a
schedule for continuing to maintain capacity at the facility sufficient to achieve
the effluent limitations and other conditions of this permit. This plan shall
address any of the following actions or any others necessary to meet this
obj ective.
1. Analysis of the present design including the introduction of any process
modifications that would establish the ability of the existing facility to
achieve the effluent limits and other requirements of this permit at specific
levels in excess of the existing design criteria specified in paragraph A
above.
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Permit No.: WA -002402-3
Expiration. Date: May 31, 2008
2. Reduction or elimination of excessive infiltration and inflow of
uncontaminated ground and surface water into the sewer system.
3. Limitation on future sewer extensions or connections or additional waste
loads.
4. Modification or expansion of facilities necessary to accommodate increased
flow or waste load.
5. Reduction of industrial or commercial flows or waste loads to allow for
increasing sanitary flow or waste load.
Engineeripg documents associated with the plan must meet the requirements of
WAC 173-240-060, "Engineering Report,"'and be approved by the Department
prior to any construction. The plan shall specify any contracts, ordinances,
methods for financing, or other arrangements necessary to achieve this objective.
In the event the Permittee intends to apply for State or Federal funding for the
design or construction of a facility project, the plan must also meet the
requirements of a "Facility Plan", as described in 40 CFR 32.2030.
C. Duty to Mitigate
The Permittee is required to take all reasonable steps to minimize or prevent any
discharge or sludge use or disposal in violation of this permit that has a reasonable
likelihood of adversely affecting human health or the environment
D. Notification of New or Altered Sources
The Permittee shall submit written notice to the Department whenever any new
discharge or a substantial change in volume or character of an existing discharge
into the POTW is proposed which: (1) would interfere with the operation of, or
exceed the design capacity of, any portion of the POTW; (2) is not part of an
approved general sewer plan or approved plans and specifications; or (3) would
be subject to pretreatment standards under 40 CFR Part 403 and Section 307(b) of
the Clean Water Act. This notice shall include an evaluation of the POTW's
ability to adequately transport and treat the added flow and/or waste load, the
quality and volume of effluent to be discharged to the POTW, and the anticipated
impact on the Permittee's effluent [40 CFR 122.42(b)].
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
E. Infiltration and Inflow Evaluation
1. The Permittee shall conduct an infiltration and inflow evaluation. Refer to
the U.S. EPA publication, UlAnalysis and Project Certification, available as
Publication No. 97-03 at: Publications Office, Department of Ecology, PO
Box 47600,.Olympia, WA, 98504-7600. Plant monitoring records may be
used to assess measurable infiltration and inflow.
2. A report shall be prepared which summarizes any measurable infiltration and
inflow. If infiltration and inflow have increased by more than fifteen (15)
percent from that found in the first report based on equivalent rainfall, the
report shall contain a plan and a schedule for: (1) locating the sources of
infiltration and inflow; and (2) correcting the problem.
3. The report shall be submitted by January 15, 2004, and annually thereafter.
F. Wasteload Assessment
The Permittee shall conduct an assessment of its flow and wasteload and submit a
report to the Department January 15, 2004 (within Final Facility Plan), and a
follow-up report May 31, 2007. The report shall contain the following: an
indication of compliance or noncompliance with the permit effluent limitations; a
comparison between the existing and design monthly average dry weather and
wet weather flows, peak flows, BOD,.and total suspended solids loadings; and the
percentage increase in these parameters since the last assessment. The report
shall also state the present and design population or population equivalent, •
projected population growth rate, and the estimated date upon which the design
capacity is projected to be reached, according to the most restrictive of the
parameters above. The interval for review and reporting may be modified if the
Department determines that a different frequency is required.
S5. OPERATION AND MAINTENANCE (O&M)
The Permittee shall at all times properly operate and maintain all facilities and systems of
treatment and control (and related appurtenances) which are installed to achieve
compliance with the terms and conditions of this permit. Proper O&M also includes
adequate laboratory controls and appropriate quality assurance procedures. This
provision requires the operation of back-up or auxiliary facilities or similar systems,
which are installed by a Permittee only when the operation is necessary to achieve
compliance with the conditions of this permit.
r ;;
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
A. Certified Operator
An operator certified for at least a Class IV plant by the State of Washington shall
be in responsible charge of the day-to-day operation of the wastewater treatment
plant. An operator certified for at least a Class III plant shall be in charge during
all regularly scheduled shifts.
B. 0 & M Program
The Permittee shall institute an adequate O&M program for its entire sewage
system. Maintenance records shall be maintained on all major electrical and
mechanical components of the treatment plant, as well as the sewage system and
pumping stations. Such records shall clearly specify the frequency and type of
maintenance recommended by the manufacturer and shall show the frequency and
type of maintenance performed. These maintenance records shall be available for
inspection at all times.
C. Short-term Reduction
If a Permittee contemplates a reduction in the level of treatment that would cause
a violation of permit discharge limitations on a short-term basis for any reason,
and such reduction cannot be avoided, the. Permittee shall give written notification
to the Department, if possible, thirty (30) days prior to such activities, detailing
the reasons for, length of time of, and the potential effects of the reduced level of
treatment. This notification does not relieve the Permittee of its obligations under
this perinit.
D. Electrical Power Failure
The Permittee is responsible for maintaining adequate safeguards to prevent the
discharge of untreated wastes or wastes not treated in accordance with the
requirements of this permit during electrical power failure at the treatment plant
and/or sewage lift stations either by means of alternate power sources, standby
generator, or retention of inadequately treated wastes. The Permittee shall
maintain Reliability Class II (EPA 430-99-74-001) at the wastewater treatment
plant, which requires primary sedimentation and disinfection.
E. Prevent Connection of Inflow
The Permittee shall strictly enforce its sewer .ordinances and not allow the
connection of inflow (roof drains, foundation drains, etc.) to the sanitary sewer
system.
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
F. Bypass Procedures
Bypass, which is the intentional diversion of waste streams from any portion of a
treatment facility, is prohibited, and the Department may take enforcement action
against a Permittee for bypass unless one of the following circumstances (1, 2, 3
or 4) is applicable.
1. Bypass for essential maintenance without the potential to cause violation of
permit limits or conditions.
• Bypass is authorized if it is for essential maintenance and does not have the
potential to cause violations of limitations or other conditions of this permit,
or adversely impact public health as determined by the Department prior to
the bypass. The Permittee shall submit prior notice, if possible at least ten
(10) days before the date of the bypass.
2. Bypass which is unavoidable, unanticipated and results in noncompliance of
this permit.
This bypass is permitted only if:
a. Bypass is unavoidable to prevent loss of life, personal injury, or severe
property damage. "Severe property damage" means substantial physical
damage to property, damage to the treatment facilities which would cause
them to become inoperable, or substantial and permanent loss of natural
resources Which can reasonably be expected to occur in the absence of a
bypass.
b. There are no feasible alternatives to the bypass, such as the use of
auxiliary treatment facilities, retention of untreated wastes, stopping
production, maintenance during normal periods of equipment downtime
(but not if adequate backup equipment should have been installed in the
exercise of reasonable engineering judgment to prevent a bypass which
occurred during normal periods of equipment downtime or preventative
maintenance), or transport of untreated wastes to another treatment
facility.
c. The Department is properly notified of the bypass as required in Special
Condition S3.E. of this permit.
3. Bypass which is anticipated and has the potential to result in noncompliance
of this permit
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
The Permittee shall notify the Department at least thirty (30) days before the
planned date of bypass. The notice shall contain: (1) a description of the
bypass and its cause; (2) an analysis of all known alternatives which would
eliminate, reduce, or mitigate the need for bypassing; (3) a cost-effectiveness
analysis of alternatives including comparative resource damage assessment;
(4) the minimum and maximum duration of bypass under each alternative;
(5) a recommendation as to the preferred alternative for conducting the
bypass; (6) the projected date of bypass initiation; (7) a statement of
compliance with SEPA; (8) a request for modification of water quality
standards as provided for in WAC 173-201A-110, if an exceedance of any
water quality standard is anticipated; and (9) steps taken or planned to reduce,
eliminate, and prevent reoccurrence of the bypass.
For probable construction: bypasses, the need to bypass is to be identified as
early in the planning process as possible. The analysis required above shall be
considered during preparation of the engineering•report or facilities plan and
plans and specifications and shall be included to the extent practical. In cases
where the probable need to bypass is determined early, continued analysis is
necessary up to and including the construction period in an effort to minimize
or eliminate the bypass.
The Department will consider the following prior to issuing an administrative
order for this type bypass:
a. If the bypass is necessary to perform construction or maintenance -related
activities essential to meet the requirements of this permit.
b. If there are feasible alternatives to bypass, such as the use of auxiliary
treatment facilities, retention of untreated wastes, stopping production,
maintenance during normal periods of equipmentdown time, or transport
of untreated wastes to another treatment facility. .
c. If the bypass is planned and scheduled to minimize adverse effects on the
public and the environment.
After consideration of the above and the adverse effects of the proposed
bypass and any other relevant factors, the Department will approve or deny
the request. The public shall be notified and given an opportunity to comment
on bypass incidents of significant duration, to the extent feasible. Approval of
a request to bypass will be by administrative order issued by the Department
under RCW 90.48.120.
4. Bypass for process control purposes in accordance with Department -approved
facility design and operational procedures
,
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
Bypass of a portion of the wastestream from a portion of the treatment train
for process control purposes is authorized, provided, the bypass reenters the
process wastestream before discharge and is measured as part of the required
effluent sampling program.
G. O&M Manual
The approved O&M Manual shall be kept available at the treatment plant and all
operators shall follow the instructions and procedures of this manual.
An O&M Manual shall be prepared by the Permittee in accordance with WAC
173-240-080 and be submitted to the Department for approval May 31, 2007.
The O&M Manual shall be reviewed by the Permittee at least annually.
Substantial changes or updates to the O&M Manual shall be submitted to the
Department whenever they are incorporated into the manual.
The O&M Manual shall include:
1. Emergency procedures for plant shutdown and cleanup in event of
wastewater system upset or failure;
2. Plant maintenance procedures;
3. The treatment plant process control monitoring schedule; and,
4. Minimum staffing levels required to operate and maintain the treatment
plant, and conduct sampling and analysis required by this permit and process
control monitoring contained in the O&M.Manual.,
S6. PRETREATMENT
A. General Requirements
1. The Permittee shall implement the Industrial Pretreatment Program in
accordance with the legal authorities, policies, procedures, and financial
provisions described in the Permittee's approved pretreatment program
submittal entitled "Industrial Pretreatment Program" and dated June 2000;
any approved revisions thereto; and the General Pretreatment Regulations
(40 CFR Part 403). At a minimum, the following pretreatment
implementation activities shall be undertaken by the Permittee:
a. Enforce categorical pretreatment standards promulgated pursuant to
Section 307(b) and (c) of the Federal Clean Water Act (hereinafter, the
Act), prohibited discharge standards as set forth in 40 CFR 403.5, local
limitations specified in Section 7.65.070 of Orduiance No. 2000-19, or
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Permit No.: WA -002402-3
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State standards, whichever are most stringent or apply at the time of
issuance or modification of a local industrial waste discharge permit.
Locally derived limitations shall be defined as pretreatment standards
under Section 307(d) of the Act and shall not be limited to categorical
industrial facilities.
b. Issue industrial waste discharge permits to all significant industrial users
[SIUs, as defined in 40 CFR 403.3(t)(i)(ii)] contributing to the treatment
system from within the City's jurisdiction. The Department 'shall
continue to issue.permits for dischargers in. other jurisdictions, as
appropriate. Industrial waste discharge permits shall contain as a
minimum, all the requirements of 40 CFR 403.8(f)(1)(iii). The Permittee
shall coordinate the permitting process with the Department regarding
any industrial facility that discharges to the POTW, which may possess a
State Waste Discharge Permit issued by the Department. Once issued, an
industrial waste discharge permit will take precedence over a State -issued
waste discharge permit.
c. Maintain and update, as necessary, records identifying the nature,
character, and volume of pollutants contributed by industrial users to the
POTW. Records shall be maintained for at least a three-year period.
d. Perform inspections, surveillance, and monitoring activities on industrial
users to determine and/or confirm compliance with applicable
pretreatment standards and requirements. A thorough inspection of SIUs
shall be conducted annually. .Frequency of regular local monitoring of
SIU wastewaters shall normally be commensurate with the character and
volume of the wastewater, but shall not be less than once per year.
Samplecollection andanalysis shall be performed in accordance with 40
CFR Part 403.12(b)(5)(ii)-(v) and 40 CFR Part 136. .
e. Enforce and obtain remedies for noncompliance by any industrial users
with applicable pretreatment standards and requirements.. Once
violations have been identified, the Permittee shall take timely and
appropriate enforcement action to address the noncompliance. The
Permittee's action shall follow its enforcement response procedures and
any amendments, thereof.
f. Publish, at least annually in the largest daily newspaper in the Permittee's
service area, a list of all nondomestic.users which, at any time in the
previous 12 months, were in significant noncompliance as defined in 40
CFR 403.8(f)(2)(vii).
g. If the Permittee elects to conduct sampling of a SIU's discharge in lieu of
the user self-monitoring, it shall sample and analyze for all regulated
pollutants in accordance with 40 CFR Part 403.12(b)(5)(ii)-(v), 40 CFR
403.12(g), and 40 CFR Part 136. The character and volume of the
samples shall be representative of the discharge and shall provide
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
adequate data to determine compliance, but in no case should sampling
occur less than two (2) times per. year.
h. Develop and maintain- a data management system designed to track the
status of the Permittee's industrial user inventory, industrial user
discharge characteristics, and compliance status. <.
Maintain adequate staff; funds, and equipment to implement its
pretreatment program.
j. Establish, where necessary, contracts or legally binding agreements with
contributing jurisdictions to ensure compliance with applicable
pretreatment requirements by commercial or industrial users within these
jurisdictions. These contracts or agreements shall identify the agency
responsible for the various implementation and enforcement activities to
be performed in the contributing jurisdiction. In addition, the Permittee
shall be required to develop a Memorandum of Understanding (or
Interlocal Agreement) that outlines the specific roles, responsibilities, and
pretreatment activities of each jurisdiction.
2. The Permittee shall develop and submit to the Department for approval, by
January 15, 2004, an updated Accidental Spill Prevention Program. The
program, as approved by the Department, shall include a schedule for
implementation, and shall become an enforceable part of these permit
conditions. -
3. The Permittee shall evaluate, at least once every two years, whether each
Significant Industrial User needs a plan to control sing discharges. For
purposes of this subsection, a slug discharge is any discharge of a nonroutine,
episodic nature, including but not limited to an accidental spill or
noncustomary batch discharge. The results of such activities shall be
available to the Department upon request. If the Permittee decides that a slug
control plan is needed, the plan shall contain, at a minimum, the following
elements: .
a. Description of discharge practices, including nonroutine batch
discharges.
b. Description of stored chemicals.
c. Procedures for immediately notifying the Permittee of slug discharges,
including any discharge that would violate a prohibition under 40 CFR
403.5(b), with procedures for follow-up written notification within five
days.
d. If necessary, procedures to prevent adverse impact from accidental spills,
including inspection and maintenance of storage areas, handling and
transfer of materials, loading and unloading operations, control of plant
site run-off, worker training, building of containment structures or
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
equipment, measures for containing toxic organic pollutants (including
solvents), and/or measures and equipment necessary for emergency
response.
4. Whenever it has been determined, on the basis of information provided to or
obtained by the Department, that any waste source contributes pollutants to
the Permittee's treatment works in violation of Subsection (b), (c), or (d) of
Section 307 of the Clean Water Act, and the Permittee has not taken adequate
corrective action, the Department shall notify the Permittee of this
determination. Failure by the Permittee to commence an appropriate
enforcement action within thirty (30) days of this notification may result in
appropriate enforcement action by the Department against the source and/or
the -Permittee.
5. Pretreatment Report
The Permittee shall provide to the Department an annual report that briefly
describes its program activities during the previous calendar year. This
report shall be submitted no later than April 15 of each year to: Washington
State Department of Ecology, Central Region Office, 15 West Yakima
Avenue, Suite 200, Yakima, Washington 98902.
The report shall include the following information:
a. An updated nondomestic inventory.
b. Results of wastewater sampling at the treatment plant as specified in
Special Condition S2.A. The Permittee shall calculate removal rates for
each pollutant and evaluate the adequacy of the existing local limitations
in Section 7.65.070 of Ordinance 2000-19 in prevention of treatment
plant interference, pass through of pollutants that could affect receiving
water quality, and sludge contamination.
c. Status of program implementation, including:
(1) Any substantial modifications to the pretreatment program as
originally approved by the Department, including staffing and
funding levels.
(2) Any interference, upset, or permit violations experienced at the
POTW that are directly attributable to wastes from industrial users.
(3) Listing of industrial users inspected and/or monitored, and a
summary of the results.
(4) Listing of industrial users scheduled for inspection and/or
monitoring for the next year, and expected frequencies.
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(5) Listing of industrial users notified of promulgated pretreatment
standards and/or local standards as required in 40 CFR
• 403.8(f)(2)(iii). Indicate which industrial users are on compliance
schedules and the final date of compliance for each.
(6) Listing of industrial users issued industrial waste discharge permits.
(7) Planned changes in the pretreatment program implementation plan.
• (See subsection A.6. below.)
d. Status of compliance activities, including:. •
(1) Listing of industrial users that failed to submit baseline monitoring
' reports or any other reports required under 40 CFR 403.12 and in
Part 6 of the Permittee's pretreatment Ordinance.
(2) Listing of industrial users that were at any time during the reporting
period not complying with Federal, State, or local pretreatment
standards or with applicable compliance schedules for achieving
those standards, and the duration of such noncompliance.
(3) Summary of enforcement activities and other corrective actions
taken or planned against noncomplying industrial users. The
Permittee shall supply to the Department a copy of the public notice
of facilities that were in significant noncompliance.
6. The Permittee shall request and obtain approval from the Department prior to
implementing any significant changes to the local pretreatment program as
approved. The procedure of 40 CFR 403.18 (b) & (c) shall be followed.
B. Monitoring Requirements
The Permittee shall monitor its influent, effluent, and sludge for the priority
pollutants identified in Tables II and.III of Appendix D of 40 CFR Part 122 as
amended, any compounds identified as a result of Special Condition. S6.B.4, and
any other pollutants expected from nondomestic sources using U.S. EPA -
approved procedures for collection, preservation, storage, and analysis. Influent,
effluent, and sludge samples shall be tested for copper, lead, silver and zinc on a
quarterly basis throughout the term of this permit, except effluent shall be tested
for all metals listed in 40 CFR 122, Appendix D, Table III concurrently when the
receiving water is sampled for metals (See Special Condition S 10.A). Influent,
effluent, and sludge samples shall be tested for the complete suite of organic and
metals priority pollutants (40 CFR 122, Appendix D, Tables II and III) on an
annual basis.
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1. The POTW influent and effluent shall besampled on a day when industrial
discharges are occurring at normal to maximum levels. Samples for the
analysis .of acid and base/neutral extractable compounds and metals shall be
24-hour composites. Samples for the analysis of volatile organic compounds
shall be collected using grab sampling techniques at equal intervals for the
total of four grab samples per day.
A single analysis for volatile pollutants (Method 624) may be run for each
monitoring day by compositing equal volumes of each grab sample directly.
in the GC purge and trap apparatus in the laboratory, with no less than 1 ml
of each grab included in the composite.
Unless otherwise indicated, all reported test data for metals shall represent
the total amount of the constituent present in all phases, whether solid,
suspended, or dissolved, elemental or combined including all oxidation
states.
Wastewater samples must be handled, prepared, and analyzed by GC/MS in
accordance with the U.S; EPA Methods 624 and 625 (October 26, 1984).
2. A sludge sample shall be collected approximately thirty (30) days after a
wastewater sample and may be taken as a single grab of residual sludge.
Sampling and analysis shall conform to U.S. EPA Methods 624 and 625
unless the Permittee requests an alternate method and it has been approved
by the Department.
3. Cyanide, phenols, and oils shall be taken as grab samples. Oils shall be
hexane soluble or equivalent, and should be measured in the influent and
effluent only.
4. In addition to quantifying pH, oil and grease, and all priority pollutants, a
reasonable attempt should be made to identify all other substances and
quantify all pollutants shown to be present by gas chromatograph/mass
spectrometer (GC/MS) analysis per 40 CFR 136, Appendix A, Methods 624
and 625. Determinations of pollutants should be attempted for each fraction,
which produces identifiable spectra on total ion plots. (reconstructed gas
chromatograms). Determinations should be attempted from all peaks with
responses 5% or greater than the nearest internal standard. The 5% value is
based on internal standard concentrations of 30 µg/1, and must be adjusted
downward if higher internal standard concentrations are used or adjusted
upward if lower internal standard concentrations are used. Non -substituted
aliphatic compounds may be expressed as total hydrocarbon content.
Identification shall be attempted by a laboratory whose computer data
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processing programs are capable of comparing sample mass spectra to a
computerized library of mass spectra, with visual confirmation by an
experienced analyst. For all detected substances which are determined to be
pollutants, additional sampling and appropriate testing shall be conducted to
determine concentration and variability, and to evaluate trends.
C. Reporting of Monitoring Results
The Permittee shall include a summary of monitoring results in the Annual
Pretreatment Report.
D. Local Limit Development
As sufficient data become available, the Permittee shall, in consultation with the
Department, reevaluate its local limits in order to prevent pass through or
interference. Upon determination by the Department that any pollutant present
causes pass through or interference, or exceeds established sludge standards, the
Permittee shall establish new local Limits or revise existing local limits as required
by 40 CFR 403.5. In addition, the Department may require revision or
establishment of local limits for any pollutant discharged from the POTW that has
a reasonable potential to exceed the Water Quality Standards, Sediment
Standards, Cr established effluent limits, or causes whole effluent toxicity. The
determination by the Department shall be in the form of an Administrative Order.
The Department may modify this permit to incorporate additional requirements
relating to the establishment and enforcement of local limits for pollutants of
concern.
Any permit modification is subject to formal due process procedures pursuant to
State and Federal law and regulation.
S7. RESIDUAL SOLIDS
The Permittee shall manage all residual solids (grit, screenings, scum, sludge and solid waste) in
accordance with the requirements of: (1) RCW 90.48.080 and Water Quality Standards; (2)
applicable sections of 40 CFR Part 503 and Chapter 173-308 WAC, "Biosolids Management";
(3) applicable sections of Chapter 173-304 WAC, "Minimum Functional. Standards for Solid
Waste Handling."
The final use and disposal of biosolids shall be done in accordance with Chapter 173-308 WAC
("Biosolids Management"), 40 CFR Part 503, and under coverage of the State general permit for
biosolids management, as applicable.
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The disposal of solid waste, other than biosolids, is regulated by the local jurisdictional
health department in accordance with State solid waste regulations.
88. ACUTE TOXICITY
A. ' Acute Rapid Screening Testing
In consideration of the Perinittee's potential to have toxicity occur and cause -
receiving water impacts the following monitoring is required. The Permittee shall
conduct using the 48-hour static test for the Daphnid method prescribed in EPA
publication EPA/600/4-90/027F, Methods for Measuring theAcute Toxicity of
Effluents and Receiving Waters to Freshwater and Marine Organisms. Testing
shall be conducted using a minimum of five effluent concentrations and a control.
A minimum of twenty (20) organisms and four (4) replicates shall be used in both.
the control and 100% effluent. Additional effluent conceritrations may also be •
run. Tests shall have a maximum normalized mortality rate of 0:20 in 100%
effluent at the 24-hour end point. Tests shall be conducted during the months of
March, August and October annually. The August and October samples shall be
taken while the treatment plant is receiving discharges from the fruit packers, if
possible. The mortality rate for an acute rapid screening test is determined in
WAC 173-205-120(2)(b) by subtracting the number of test organisms living'in
100% effluent from the number of test organisms living in the control and
dividing the result by the number of test organisms living in the control.
In the event mortality exceeds 20% at 24 hours in 100.% effluent, the testing shall
be extended to 96 hours. The Permittee shall also actively investigate the source
of toxicity. The toxicity test and investigation results shall be reported to the
Department within thirty (30) days of the rapid screening test failure.
B. Sampling and Reporting Requirements
1. All reports for effluent characterization or.compliance monitoring shall be
submitted in accordance with the most recent version of Department of
Ecology Publication # WQ-R-95-80, Laboratory Guidance and Whole.
Effluent Toxicity Test Review Criteria in regards to format and content.
Reports shall contain bench sheets and reference toxicant results for test
methods. If the lab provides the toxicity test data on "floppy disk for .
electronic entry into the Department's database, then the Permittee shall send
the disk to the Department along with the test report, bench sheets, and
reference toxicant results.
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
2. Testing shall be conducted on 24-hour composite effluent samples. Samples
taken for toxicity testing shall be cooled to four (4) degrees Celsius while
being collected and shall be sent to the lab immediately upon completion.
The lab shall begin the toxicity testing as soon as possible but no later than
thirty-six (36) hours after sampling was ended.
3. All samples and test solutions for toxicity testing shall have water quality
measurements as specified in Department of Ecology. Publication # WQ-R-
95-80, Laboratory Guidance and Whole Effluent Toxicity Test Review
Criteria or most recent version thereof.
4. All toxicity tests shall meet quality assurance criteria and test conditions in
the most recent versions of the EPA manual listed in subsection A. and the
Department of Ecology Publication # WQ-R-95-80, Laboratory Guidance
and Whole Effluent Toxicity Test Review Criteria. If test results are
' determined to be invalid or anomalous by the Department, testing shall be
repeated with freshly collected effluent.
5. Control water and dilution water shall be laboratory water meeting the
requirements of the EPA manual listed in subsection A or pristine natural
water of sufficient quality for good control performance.
6.. Final effluent samples for whole effluent toxicity testing shall be chemically
dechlorinated with sodium thiosulfate just prior to test initiation. No more
sodium thiosulfate shall be added than is necessary to neutralize the chlorine.
7. The Permittee may choose to conduct a full dilution series test during
compliance monitoring in order to determine dose response.' In this case, the
series must have a minimum of five (5) effluent concentrations and a control.
The series of concentrations must include the acute critical effluent
concentration (ACEC) of 66.2%.
8. All whole effluent toxicity tests, effluent screening tests, and rapid screeriing
tests that involve hypothesis testing and do not comply with the acute
statistical power standard of 29% as defined in WAC 173-205-020 must be
repeated on a fresh sample with an increased number of replicates to increase
the power.
9. Routine WET monitoring reports shall be submitted to the Department
within sixty (60) days of the sampling event.
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
• 10. The Permittee shall submit a Acute WET Testing Summary Report,
summarizing the results of all acute WET Testing that has occurred during
the permit cycle, May 31, 2007.
S9. CHRONIC TOXICITY
A. Effluent Limit for. Chronic Toxicity
The chronic toxicity limit is no statistically significant difference in test
organism response between the chronic critical effluent concentration
(CCEC), 15.1% of the effluent, and the control.
The CCEC means the maximum concentration of effluent allowable at the
boundary of the mixing zone .assigned in Section S 1.B pursuant to WAC 173-
201A-100. The CCEC equals 15.1 % effluent.
In the event of failure to pass the test described in subsection B. of this section for
compliance with the effluent limit for chronic toxicity, the Permittee is considered
to be in compliance with all permit requirements for chronic whole effluent
toxicity as long as the requirements in subsection C. are being met to the
satisfaction of the Department.
B. Monitoring for Compliance With an Effluent Limit for Chronic Toxicity
The Permittee shall conduct monitoring to determine compliance with the effluent
limit for chronic toxicity. The chronic toxicity tests shall be performed using at a
minimum the CCEC, the ACEC, and a control. Chronic toxicity testing shall
follow protocols, monitoring requirements, and quality assurance/quality control
procedures specified in this Section. A written report shall be submitted to the
Department within sixty (60) days after the sample, date. This written report
shall contain the results of hypothesis testing conducted as described in this
subsection using both the ACEC and CCEC versus the control.
Monitoring to determine compliance with the effluent limit shall be conducted in
March, September and November, using Ceriodaphnia dubia, in accordance with
EPA/600/4-91/002. When possible, sampling shall occur concurrently with
effluent and receiving water sampling specified in Special Condition 510.A and B
of this permit.
The Permittee is in violation of the effluent limit for chronic toxicity in subsection
A. and shall immediately implement subsection C. if any chronic toxicity test
conducted for compliance monitoring determines a statistically significant
Page 31 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
difference in response between the control and the CCEC using hypothesis testing
at the 0.05 level of significance (Appendix H, EPA/600/4-89/001). If the
difference in response between the control and the CCEC is less than 20%, the
hypothesis test shall be conducted at the 0.01 level of significance.
In order to establish whether the chronic toxicity limit is eligible for removal from
future permits, the Permittee shall also conduct this same hypothesis test
(Appendix H, EPA/600/4-89/001) to determine if a statistically significant
difference in response exists between the ACEC and the control.
C. Response to Noncompliance With an Effluent Limit for Chronic Toxicity
If a toxicity test conducted for compliance monitoring under subsection B.
determines a statistically significant difference in response between the CCEC
and the control, the Permittee shall begin additional compliance monitoring
within one week from the time of receiving the test results. This additional
monitoring shall be conducted monthly for three consecutive months using the
same test and species as the failed compliance test. Testing shall be conducted
using a series of at least five effluent concentrations and a control in order to be
able to_ determine appropriate point estimates. One of these effluent
concentrations shall equal the CCEC and be compared statistically to the nontoxic
control in order to determine compliance with the effluent limit for chronic
toxicity as described in subsection B. The discharger shall return to the original
monitoring frequency -in subsection B. after completion of the additional
compliance monitoring.
If the Permittee believes that a test indicating noncompliance will be identified by
the Department as an anomalous test result, the Permittee may notify the
Department that the complianceiest result might be anomalous and that the
Permittee.intends to take only oneadditional sample for toxicity testing and wait
for notification from the Department before completing the additional monitoring
required in this subsection. The notification to the Department shall accompany
the report of the compliance test result and identify the reason for considering the
compliance test result to be anomalous. The Permittee shall complete all of the
additional monitoring required in this subsection as soon as possible after
notification by the Department that the compliance test result was not anomalous.
If the one additional sample fails to comply with the effluent limit for chronic
toxicity, then the Permittee shall proceed without delay to complete all of the
additional monitoring required in this subsection. The one additional test result
shall replace the compliance test result upon determination by the Department that
the -compliance test result was anomalous.
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
If all of the additional compliance monitoring conducted.in accordance with this
subsection complies with the permit limit, the Permittee shall search all pertinent
and recent facility records (operating records, monitoring results, inspection
records, spill reports, weather records, production records, raw material.
purchases, pretreatment records, etc.) and submit a report to the Department on
possible causes and preventive measures for the transient toxicity event which
triggered the additional compliance monitoring.
If toxicity occurs in violation of the chronic toxicity limit during the additional
compliance monitoring, the Permittee shall submit a Toxicity
Identification/Reduction Evaluation (TI/RE) plan to the Department within 60
days after the sample date. The TURF plan shall be based on WAC 173-205-
100(2) and shall be implemented in accordance with WAC 173-205-100(3).
D. Sampling and Reporting Requirements
1. All reports for effluent characterization or compliance monitoring shall be
submitted in accordance with the most recent version of Department of
Ecology Publication # WQ-R-95-80, Laboratory Guidance and Whole
Effluent Toxicity Test Review Criteria in regards to format and content.
Reports shall contain bench sheets and reference toxicant results.for test
methods. If the lab provides the toxicity test data on floppy disk for
electronic entry into the Department's database, then the Permittee shall send
the disk to the Department along with the test report, bench sheets, and
reference toxicant results.
2. Testing shall be conducted on 24-hour composite effluent samples. Samples
taken for toxicity testing shall be cooled to 4 degrees Celsius while being
collected and shall be sent to the lab immediately upon completion. The lab
shall begin the toxicity testing as soon as possible but no later than thirty-six
(36) hours after sampling was ended.
3. All samples and test solutions for toxicity testing shall have water quality
measurements as specified in Department of Ecology Publication # WQ-R-
95-80, Laboratory Guidance and Whole Effluent Toxicity Test Review
Criteria or most recent version thereof.
4. All toxicity tests shall meet quality assurance criteria and test conditions in
the most recent versions of the EPA manual listed in subsection A. and the
Department of Ecology Publication # WQ-R-95-80, Laboratory Guidance
and Whole Effluent Toxicity Test Review Criteria. If'test results are
determined to be invalid or anomalous by the Department, testing shall be
repeated with freshly collected effluent.
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
5. Control water and dilution water shall be laboratory water meeting the
requirements of the EPA manual listed in subsection A or pristine natural
water of sufficient quality for good control performance.
6. Final effluent samples for whole effluent toxicity testing shall be chemically
dechlorinated with sodium thiosulfate just prior to test initiation. No more
sodium thiosulfate shall be added than is necessary to neutralize the.chlorine:
7. The Permittee may choose to conduct a full dilution series test during
compliance monitoring in order to determine dose response. In this case, the
series must have a minimum of five (5) effluent concentrations and a control.
The series of concentrations must include the CCEC and the ACEC. The
CCEC and the ACEC may either substitute for the effluent concentration that
is closest to it in the dilution series or be an extra effluent concentration.
8. All whole effluent toxicity, tests that involve hypothesis testing and do not
comply with the chronic statistical power standard of 39%.as defined in
WAC 173-205-020 must be repeated on a fresh sample with an increased
number of replicates to increase the power.
9. The Permittee shall submit a Chronic WET Testing Summary Report,
summarizing the results of all chronic WET Testing that has occurred during
the permit cycle, May 31, 2007.
S10. RECEIVING WATER AND EFFLUENT STUDY
The Permittee shall collect receiving water information necessary to determine if the
effluent has a reasonable potential to cause a violation of the water quality standards. If
reasonable potential exists the Department will use this information to calculate effluent
limits.
A. Effluent Analysis
The Permittee shall analyze the wastewater discharge for hardness, arsenic,
copper, lead, nickel, chromium, zinc, cadmium, selenium, silver, and mercury at
least eight (8) times during the term of the permit. '
Sample events shall coincide with the receiving water samples (see Special
Condition S10.B). When possible, sampling shall be concurrent with acute and
chronic WET Testing sampling events specified in Special Conditions S8.B and
S9.B of this permit.
Page 34 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
All analysis for metals must use the methods given in 40 CFR Part 136 and be
reported as total recoverable. The Permittee should use the clean sampling
guidance for collection of metals samples. The minimum detection levels used
for the analysis shall be:
B. Receiving Water Analysis
The Permittee shall sample and analyze the receiving water for hardness,
temperature; pH, alkalinity, mercury, and arsenic. The following metals shall be
analyzed for both total recoverable and dissolved: zinc, copper, lead, silver,
selenium, cadmium, nickel, and chromium.
Sampling of the receiving water shall occur on a quarterly basis, beginning in
September 2004 and ending in September 2006. The Permittee shall collect a
minimum of eight (8) samples from the receiving water. The sampling station
accuracy requirements shall be within twenty (20) meters. The receiving water
sampling location should be outside the zone of influence of the effluent.
The Permittee shall follow the clean sampling techniques (Method 1669:
Sampling Ambient Water for Trace Metals at EPA Water Quality Criteria Levels,
EPA Publication No. 821-R-95-034, April 1995). All chemical analysis shall be
conducted according to methods given in 40 CFR 136 and shall have the
following detection levels:
Copper
1.0 µg/L
.Lead .
. 1.0 µg/L .
Nickel
• • 1.0 µg/L
Chromium
1.0 µg/L
Zinc
2.0 µg/L
Cadmium
.0.1 µg/L
Selenium
2.0 p.g/L
Silver
0.2µg/L •
Mercury0.2
µg/L
Arsenic
.1.0. µg/L
B. Receiving Water Analysis
The Permittee shall sample and analyze the receiving water for hardness,
temperature; pH, alkalinity, mercury, and arsenic. The following metals shall be
analyzed for both total recoverable and dissolved: zinc, copper, lead, silver,
selenium, cadmium, nickel, and chromium.
Sampling of the receiving water shall occur on a quarterly basis, beginning in
September 2004 and ending in September 2006. The Permittee shall collect a
minimum of eight (8) samples from the receiving water. The sampling station
accuracy requirements shall be within twenty (20) meters. The receiving water
sampling location should be outside the zone of influence of the effluent.
The Permittee shall follow the clean sampling techniques (Method 1669:
Sampling Ambient Water for Trace Metals at EPA Water Quality Criteria Levels,
EPA Publication No. 821-R-95-034, April 1995). All chemical analysis shall be
conducted according to methods given in 40 CFR 136 and shall have the
following detection levels:
Page 35 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
P Ylj rl ` LY54: v
t 9 . f�., 1 y i 3"3 'fl a
Tom, -- y n : r
'fr i!;. �?-..�'{.'f ti3 !
:GG
vtY,<
(4t %_ y. t." I : r
.IYys��s-�. ` ` ''` %pp J' ,,,,Wei ,
.. . r rS� . Y �s i &
�:.Y >C.,T ct ..,�s. �1.. _;5�-
t.
Copper
1.0 µg/L
Lead
1.0 µg/L
Nickel
1.0 µg/L
Chromium
1.0 µg/L
Zinc
2.0 µg/L
Cadmium
0.1 µg/L
Selenium
2.0 µg/L
Silver,0.2
µg/L
'
Mercur-
0.2 µg/L
Arsenic
1.0 µg/L
Any subsequent sampling and analysis shall also meet these requirements. The
Permittee may conduct a cooperative receiving water study with other NPDES
Permittees discharging in the same vicinity. The Permittee shall submit the
results of the study to the Department May 31, 2007.
C. Quality Assurance Project Plan (QAPP)
All sampling and analysis shall be conducted in accordance with the guidelines
given in Guidelines and Specifications for Preparing Quality Assurance Project
Plans, Ecology Publication 91-16. The Permittee shall submit a sampling and
quality assurance plan for Department review and approval by October 1, 2003.
S11. FACILITY PLAN
A. Final Facility Plan .
By January 1, 2004, two copies of an approvable Facility Plan shall be prepared
by the Permittee in accordance with WAC 173-240 and submitted to the
Department for review and approval.
In addition to the requirements detailed in 173-240-060, the Permittee shall
address the following issues in the Facility Plan:
1. A comprehensive water quality evaluation, addressing all conventional
and toxic pollutants, that demonstrates the discharge will be in compliance
Page 36 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
with the State's Surface Water Quality Standards or details how the City
will achieve compliance;
2. The final treatment plant flow configuration, including treatment of Del
Monte flows;
3. Provide the assumptions and calculations that are the basis of the capacity
calculations in Section 5.4 of the draft Facility Plan; •
4. Provide the assumptions and calculations that are the basis of the design of
the required upgrades;
5. The impacts of treating food processing wastewater from Del Monte in the
treatment plant, rather than the spray field;
6. The impact of the intermediate clarifier on the plant capacity, which was
brought on line following submittal of the draft Facility Plan; and,
7. Documentation for the SEPA and SERP determinations, including the
SERP Environmental Report, copies. of any written com ments the City
received from agencies with jurisdiction, records of the City's efforts to
contact agencies that did not provide written comments, records from the
public hearing, a copy of the SEPA Environmental Checklist, and the
SEPA Threshold Determination.
In addition, the Facility Plan shall contain any appropriate requirements as
described in the "Water Reclamation and Reuse Standards" (Washington State
Department of Ecology and Department of Health, 1997). As required by RCW
90.48.112, the document must address the feasibility of using reclaimed water as
defined in RCW 90.46.010.
S12. OUTFALL EVALUATION
The Permittee shall inspect the submerged portion of the outfall line and.diffuser to
document its integrity and continued function. Deposition of sediments in the area of the
outfall shall also be documented. Photographic verification shall be included in the
report. The inspection report shall be received the.Department by January 15, 2005.
S13. SCHEDULE OF COMPLIANCE
The Permittee shall achieve compliance with the State's Surface Water Quality Standards
for Copper, Lead, Silver and Zinc, by January 16, 2008. The Permittee shall undertake
the following activities in fulfillment of this Special Condition.
Page 37 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
A. Scope of Work Report
The Permittee shall submit to the Department a Scope of Work that describes
elements of the study required by section B. of this condition to achieve -
compliance with the State's Surface Water Quality Standards for Copper, Lead,
Silver and Zinc. This report shall be submitted to the Department by January 1,
2004.
.B. Metals Study
The Permittee shall conduct a comprehensive study to determine measures to be
taken to achieve compliance with the State's Surface Water Quality Standards for
Copper, Lead, Silver and Zinc. The study shall include, but not be limited by, the
following corrective/mitigative measures:
• pH adjustment of the City's water supply;
• source reduction; and,
• treatment.
C. Assessment Report
The Permittee shall submit to the Department, for review and approval, a
comprehensive Assessment Report detailing the results of the study to achieve
compliance with the State's Surface Water Quality Standards for Copper, Lead,
Silver and Zinc. This report shall be submitted to the Departinent by July 15,
2006. This report shall include a decision by the Permittee as to•the
corrective/mitigative action(s) that will be taken to achieve compliance with the
water quality Standards.
D. Water -Effects Ratio Study
In the event the Permittee determines that the desired action is to conduct a
Water -Effects Ratio (WER) Study, the Permittee shall submit a WER Study Plan
with the Assessment Report required by section C of this condition. The
Permittee shall follow the Guidance on Determination and Use of Water -Effect
Ratios for Metals, EPA -823-B-94-001, and guidance as outlined in Appendix 6 of
the Department's Permit Writers Manual to plan for the study and testing. This
EPA document and the Department's Appendix 6 guidance on WER study must
be reviewed by the Permittee for a full understanding of the requirements for
determining a water effect ratio prior to proceeding with the study. The WER
Page 38 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
Study Plan shall include a schedule detailing the timetable and completion date of
the study...
E. Engineering Report
In the event the recommended outcome of the Assessment Report involves
physical modification(s) of the POTW, the Permittee is required to submit an
Engineering Report to the Department for review and approval, May 31, 2007.
The Engineering Report shall be written in accordance with WAC 173-240-060.
Page 39 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
GENERAL CONDITIONS
GJ.. SIGNATORY REQUIREMENTS
All applications, reports, or information submitted to the Department shall be signed and
certified.
A. All permit applications shall be signed by either a principal executive officer or a
ranking elected official.
B. All reports required by this permit and other information requested by the
Department shall be signed by a person described above or by a duly. authorized
representative of that person. A person is a duly. authorized representative only if:
1. The authorization is made in writing by a person described above and
submitted to the Department.
2. The authorization specifies either an individual or a position having
responsibility for the overall operation of the regulated facility; such as the
position of plant manager, superintendent, position of equivalent
responsibility, or an individual or position having overall responsibility for
environmental matters. (A duly authorized representative may thus be either a
named individual or any individual occupying a named position.)
C. Changes to authorization. If an authorization under paragraph B.2 above is no
longer accurate because a different individual or position has responsibility for the
overall operation of the facility, a new authorization satisfying the requirements of
paragraph B.2 above must be submitted to the Department prior to or together
with any reports, information, or applications to be signed by an authorized
representative.
D. Certification. Any person signing a document under this section shall make the
following certification:
I certifyunder penalty of law, that this document and all .
attachments were prepared under my direction or supervision in
accordance with a system designed to assure that qualified
personnel properly gathered and evaluated the information
submitted. Based on my inquiry of the person or persons who
manage the system or those persons directly responsible for
gathering information, the information submitted is, to the best
of my knowledge and belief, true, accurate, and complete. I am
aware that there are significant penalties for submitting false
Page 40 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
information, including the possibility of fine and imprisonment
for knowing violations.
G2. RIGHT OF INSPECTION AND ENTRY
The Permittee shall allow an authorized representative of the Department, upon the
presentation of credentials and such other documents as may be required bylaw:
A. To enter upon the premises where a discharge is located or where any records
must be kept under the terms and.conditions of this permit.
B. To have access to and copy - at reasonable times and at reasonable cost - any
records required to be kept under the terms and conditions of this permit.
C. To inspect - at reasonable times - any facilities, equipment (including monitoring
and control equipment), 'practices, methods, or operations. regulated or required
under this permit. .
D. To sample or monitor - at reasonable times - any substances or parameters at any
location for purposes of assuring permit compliance or as otherwise authorized by
the Clean Water Act.
G3. PERMIT ACTIONS
This permit may be modified, revoked and reissued, or terminated either at the request of
any interested person (including the permittee) or upon the Department's initiative.
However, the permit may only be modified, revoked and reissued, or terminated for the
reasons specified in 40 CFR 122.62, 122.64 or WAC 173-220-150 according to the
procedures of 40 CFR 124.5.
A. The following are causes for terminating this permit during its term, or for
denying a permit renewal application:
1. Violation of any permit term or condition.
2. Obtaining a permit by misrepresentation or failure to disclose all relevant
facts.
3. A material change in quantity or type of waste disposal.
4. A determination that the permitted activity endangers human health or the
environment, or contributes to water quality standards violations and can only
be regulated to acceptable levels by permit modification or termination [40
CFR part 122.64(3)].
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
5. A change in any .condition that requires either a temporary or permanent
reduction, or elimination of any discharge or sludge use or disposal practice
controlled by the permit [40 CFR part 122.64(4)].
6. Nonpayment of fees assessed pursuant to RCW 90.48.465.
7. Failure or refusal of the permittee to allow entry as required in RCW
90.48.090.
B. The following are causes for modification but not revocation and reissuance
'except when the permittee requests or agrees:
1. A material change in the condition of the waters of the State.
2. New information not available at the time of permit issuance that would have
justified the application of different permit conditions.
3. Material and substantial alterations or additions to the permitted facility or
activities which occurred after this permit issuance.
4. Promulgation of new or amended standards or regulations having a direct
bearing upon permit conditions, or requiring permit revision.
5. The Permittee has requested a modification based onsbther rationale meeting
the criteria of 40 CFR part 122.62.
6. The Department has determined that good cause exists for modification of a
compliance schedule, and the modification will -not violate statutory deadlines.
7. Incorporation of an approved local pretreatment program into a municipality's
permit.'
C. The following are causes for modification or alternatively revocation and
reissuance:
1. Cause exists for termination for reasons listed in Al through A7 of this
section, and the Department determines that modification or revocation and
reissuance is appropriate.
2. The Department has received notification of a proposed transfer of the permit.
A permit may also be modified to reflect a transfer after the effective date of
an automatic transfer (General Condition G8) but will not be revoked and
reissued after the effective date of the transfer except upon the request of the
new permittee.
G4. REPORTING A, CAUSE FOR MODIFICATION
ti
The Permittee shall submit a new application, or a supplement.to the previous
application, along.with required engineering plans and reports whenever a material
. change to the facility or in the quantity or type of discharge is anticipated which is not
specifically authorized by this permit. This application shall be submitted at least sixty
(60) days prior to any proposed changes. The filing of a request by the Permittee for a
Page 42 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
permit modification, revocation and reissuance, or termination, or a notification of •
planned changes or anticipated noncompliance does not relieve the Permittee of the duty
to comply with the existing permit until it is modified or reissued.
G5. PLAN REVIEW REQUIRED
Prior to constructing or modifying any wastewater control facilities, an engineering report
and detailed plans and specifications shall be submitted to the Department for approval in
accordance with Chapter 173-240 WAC. Engineering reports, plans, and specifications
shall be submitted at least one hundred eighty (180) days prior to the planned start of
construction unless a shorter time is approved by Ecology. Facilities shall be constructed
and operated in accordance with the approved plans.
G6. COMPLIANCE WITH OTHER LAWS AND STATUTES
Nothing in this permit shall be construed as excusing the Permittee from compliance with
any applicable Federal, State, or local statutes, ordinances, or regulations.
G7. DUTY TO REAPPLY
The.Perrnittee shall apply for permit renewal at least one (1) year prior to the specified
expiration date of this permit.
G8. TRANSFER OF THIS PERMIT
In the event of any change in control or ownership of facilities from which the authorized
discharge emanate, the Permittee shall notify the succeeding owner or controller of the
existence of this permit by letter, a copy of which shall be forwavded to the Department.
A. Transfers by Modification
Except as provided in paragraph (B) below, this permit may be transferred by the
Permittee to a new owner or operator only if this permit has been modified or
revoked and reissued under 40 CFR 122.62(b)(2), or a minor modification made
under 40 CFR 122.63(d), to identify the new Permittee and incorporate such other
requirements as may be necessary under the Clean Water Act.
B. Automatic Transfers
This permit may be automatically transferred to a new Permittee if:
1. The Permittee notifies the Department at least 30 days in advance of the
proposed transfer date.
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Permit No.: WA -002402-3
Expiration Date: May 31, 2008
2. The notice includes a written agreement between the existing and new
Permittees containing a specific date transfer of permit responsibility,
coverage, and liability between them.
3. The Department does not notify the existing Permittee and the proposed new
Permittee of its intent to modify or revoke and reissue this permit. A
modification under this subparagraph may also be minor modification under
40 CFR 122.63. If this'notice is not received, the transfer is effective on. the
date specified in the written agreement.
G9. REDUCED PRODUCTION FOR COMPLIANCE
The Permittee, in order to maintain compliance with its permit, shall control production
and/or all discharges upon reduction, loss, failure, or bypass of the treatment facility until
the facility is restored or an alternative method of treatment is provided. This
requirement applies in the situation where, among other things, the primary source of
power of the treatment facility is reduced, lost, or fails.
G10. REMOVED SUBSTANCES
Collected screenings, grit, solids, sludges, filter backwash, or other pollutants removed in
the course of treatment or control of wastewaters shall not be resuspended or
reintroduced to the final effluent stream for discharge to State waters.
G11. DUTY TO PROVIDE INFORMATION
The Permittee shall submit to the Department, within a reasonable time, all information
which the Department may request to determine whether cause exists for modifying,
revoking and reissuing, or terminating this permit or to determine compliance with this
permit. The Permittee shall also submit to the Department upon request, copies of
records required to be kept by this permit [40 CFR 122.41(h)] .
G12. OTHER REQUIREMENTS OF 40 CFR
All other requirements of 40 CFR 122.41 and 122.42 are incorporated in this permit by
reference.
G13. ADDITIONAL MONITORING
The Department May establish specific monitoring requirements'in addition.to those
contained in this permit by administrative order or permit modification.
Page 44 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
G14. PAYMENT OF FEES
The Permittee shall submit payment of fees associated with this permit as assessed by the
Department.
G15. PENALTIES FOR VIOLATING PERMIT CONDITIONS
Any person who is found guilty of willfully violating the terms and conditions of this
permit shall be deemed guilty of a crime, and upon conviction thereof shall be punished
bya fine of up to -ten thousand dollars ($10,000) and costs of prdsecution,.or by
imprisonment in the discretion of the court. Each day upon which a willful violation
occurs may be deemed a separate and additional violation.
Any person who violates the terms and conditions of a waste discharge permit shall incur,
in addition to any other penalty as provided by law, a civil penalty in the amount of up to
ten thousand dollars ($10,000) for every such violation. Each and every such violation
shall be a separate and distinct offense, and in case of a continuing violation, every day's
continuance shall be deemed to be a separate and distinct violation.
G16. UPSET
Definition "Upset" means an exceptional incident in which there is unintentional. and
temporary noncompliance with technology-based permit effluent limitations because of
factors beyond the reasonable control .of the Permittee. An upset does not include
noncompliance to, the extent caused by operational error, improperly designed treatment
facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or
improper operation.
An upset constitutes an affirmative defense to an action broughtttfor noncompliance with
such technology-based permit effluent limitations if the requirements of the following
paragraph are met.
A Permittee who wishes to establish the affirmative defense of upset shall demonstrate,
through properly signed, contemporaneous operating logs, or other relevant evidence
that:
1) an upset occurred and that the Permittee can identify the cause(s) of the upset; 2) the
permitted facility was being properly operated at the time of the upset; 3) the Perxnittee
submitted notice of the upset as required in condition S3.E; and 4) the Permittee
complied with any remedial measures required under S5. of this permit.
In any enforcement proceeding the Permittee seeking to establish the occurrence of an
upset has the burden of proof.
Page 45 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
G17. PROPERTY RIGHTS
This permit does not convey any property rights of any sort, or any exclusive privilege.
G18. DUTY TO COMPLY
The Permittee shall comply with all conditions of this permit. Any permit
noncompliance constitutes a violation of the Clean Water Act and is grounds for
enforcement action; for permit termination, revocation and reissuance, or modification; or
denial of a permit renewal application.
G19. TOXIC POLLUTANTS
The Permittee shall comply with effluent standards or prohibitions established under
Section 307(a) of the Clean Water Act for toxic pollutants within the time provided in the
regulations that establish those standards or prohibitions, even if this permit has not yet
been modified to incorporate the requirement.
G20. PENALTIES FOR TAMPERING
The Clean Water Act provides that any person who falsifies, tampers with, or knowingly
renders inaccurate any monitoring device or method required to be maintained under this
permit,shall, uponconviction; be punished by a fine of not more than ten thousand dollars
($10,000) per violation, or by imprisonment for not more than two years per violation, or
by both. If a conviction of a person is for a violation committed after a first conviction of
such person under this Condition, punishment shall be a fine of not more than twenty
thousand dollars ($20,000) per day of violation, or by imprisonment of not more than
four (4) years, or by both.
G21. REPORTING PLANNED CHANGES
The Permittee shall, as soon as possible, give notice to the Department of planned
physical alterations or additions to the permitted facility, production increases, or process
modification which will result in: 1) the permitted facility being determined to be a new
source pursuant to 40 CFR 122.29(b); 2) a significant change in the nature or an increase
in quantity of pollutants discharged; or 3) a significant change in the Permittee's sludge
use or disposal practices. Following such notice, this permit may be modified, or
revoked and reissued pursuant to 40 CFR 122.62(a) to specify and limit any pollutants
not previously limited. Until such modification is effective, any new or increased
discharge in excess of permit limits or not specifically authorized by this permit
constitutes a violation of the terms and conditions of this permit.
Page 46 of 46
Permit No.: WA -002402-3
Expiration Date: May 31, 2008
G22. REPORTING ANTICIPATED NON-COMPLIANCE
The Permittee shall give advance notice to the Department by submission of a new
application or supplement thereto at least one hundred and eighty (180) days prior to
commencement of such discharges, of any facility expansions,production increases, or
other planned changes, such as process modifications,in the permitted facility or activity
which may result in noncompliance with permit limits or conditions. Any maintenance
of facilities, which might necessitate unavoidable interruption of operation and
degradation of effluent quality, shall be scheduled during noncritical water quality
periods and carried out in a manner approved by the Department,
G23. REPORTING OTHER INFORMATION
Where the Permittee becomes aware that it failed to submit any relevant facts in a permit
application, or submitted incorrect information in a permit application, or in any report to
the Department, it shall promptly submit such facts or information.
G24. COMPLIANCE SCHEDULES
Reports of compliance or noncompliance with, or any progress reports on,. interim and
final requirements contained in any compliance schedule of this permit shall be submitted
no later than fourteen (14) days following each schedule date.
DRAFT
COMBINED QUALITY ASSURANCE PROJECT
PLAN/SAMPLING AND ANALYSIS PLAN (QAPP/SAP)
2004-2006
Receiving Water and Effluent Study
Prepared by,
City of Yakima Regional Wastewater Treatment Plant Staff
City of Yakima Regional Wastewater Treatment Plant
2220 East Viola
Yakima, WA 98926
December 8, 2003
Approvals
Washington State Department of Ecology, Central Regional Office
David Dunn Date
City of Yakima, Yakima Regional Wastewater Treatment Plant
Doug Mayo, Division Manager Date
Frontier Geosciences, Trace Metals Laboratory
Misty Kennard, Senior Project Manager Date
REV 1
Table of Contents
TABLE OF CONTENTS 2
INTRODUCTION 4
PROJECT DESCRIPTION 4
SCHEDULE 4
Table 1. Receiving Water and Effluent Study Sample Schedule 4
SAMPLING SITES 4
PARAMETERS 5
Table 2. Receiving Water and Effluent Study Parameters 5
BACKGROUND 5
EXISTING DATA 5
Table 3. 1998-1999 Effluent and Receiving Water Clean Metals Summary 6
Table 4. 1998-1999 Effluent and Receiving Water Conventional Parameter Stnnrrray6
Table S. 2003 Effluent Metals Monitoring Results 6
SAMPLING DESIGN 7
SAMPLING SITES 7
Receiving Water 7
Effluent 7
FIELD PROCEDURES 7
SAMPLE COLLECTION 7
Table 6. Sample Container, Preservation and Holding Time Guide 9
TEMPERATURE MEASUREMENT 9
LABORATORY PROCEDURES 9
METALS 10
CONVENTIONALS 10
Table 7. Laboratory Procedures 10
MEASUREMENT QUALITY OBJECTIVES AND QUALITY CONTROL PROCEDURES 11
ACCURACY AND BIAS 1 1
Temperature Measurement 11
Sample Collection 11
Matrix Effects 11
Laboratory Procedures 11
Table 8. Laboratory Measurement Quality Objectives for Accuracy and Bias 12
PRECISION 12
Field Procedures 12
Labo•atoy Procedures 12
Table 9. Laboratory Measurement Quality Objectives for Precision 13
COMPLETENESS 13
COMPARABILITY AND REPRESENTATIVENESS 13
DATA ANALYSIS AND USE 13
PROJECT ORGANIZATION 14
CITY OF YAKIMA 14
FRONTIER GEOSCIENCE 14
REVI
2
STUDY SCHEDULE 14
Table 10. Proposed Schedule for the Receiving Water and Effluent Study 14
REFERENCES 15
APPENDIX A 16
THE CITY OF YAKIMA WASTEWATER PLANT CLEAN METAL SAMPLING STANDARD PROCEDURE 16
APPENDIX B 24
FRONTIER GEOSCIENCES CHAIN -OF -CUSTODY 24
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3
Introduction
The purpose of the Receiving Water and Effluent Study (study) is to collect representative
data on metals concentrations and ancillary parameters in the City of Yakima Regional
Wastewater Treatment Plant (City) effluent and receiving water (Yakima River). Study
data are intended for use by the Washington State Department of Ecology (Ecology) in
determining if City effluent has a reasonable potential to violate water quality standards
and, if necessary, in calculating discharge limits for the City's next National Pollutant
Discharge Elimination System (NPDES) permit. This QAPP/SAP establishes study data
quality objectives and describes the sampling, analysis, and data review procedures
chosen to meet these objectives.
Project Description
Schedule
As required by Special Condition S10. of the City's current NPDES permit (Ecology,
2003), the City will sample and analyze the effluent and the receiving water at least eight
times on a quarterly basis beginning in September 2004 and ending in September 2006.
Effluent sample collection and receiving water sample collection will occur on the sarne
day during scheduled sample months. Study sampling will also occur on the same day as
acute and/or chronic WET test sampling when scheduled months coincide. The study
sampling schedule and coincident WET test sampling dates are presented in Table 1.
Table 1. Receiving Water and Effluent Stud v Sample Schedule
Month
Sampling Sites
Coincident
WET Test
Sampling
September, 2004
Effluent, Receiving Water
Chronic
December, 2004
Effluent, Receiving Water
March, 2005
Effluent, Receiving Water
Acute, Chronic
June, 2005
Effluent, Receiving Water
September, 2005
Effluent, Receiving Water
Chronic
December, 2005
Effluent, Receiving Water
March, 2006
Effluent, Receiving Water
Acute, Chronic
June, 2006
Effluent, Receiving Water
Sampling Sites
The effluent sampling site will provide samples that are representative of effluent
conditions immediately prior to discharge to the receiving water. The receiving water
sampling site will provide samples that are representative of ambient Yakima River water
that is not influenced by City wastewater effluent. The location of both sampling sites
will remain fixed for the duration of the study.
REV 1
4
Parameters
The study parameters are detailed in Table 2. The receiving water parameter list and the
effluent parameter lists are identical, each consisting of both total and dissolved
measurements for arsenic, mercury, zinc, copper, lead, silver, selenium, cadmium, nickel,
and chromium. Each list also includes and several conventional parameters: hardness,
temperature, pH, and alkalinity. Samples from each study sampling event will be
analyzed for the complete set of parameters.
Table 2. Receivinil Water and Effluent Stud v Parameters
Background
Existing Data
Existing clean metals data from the study sampling points are limited to measurements
from samples collected by City personnel between 1998 and the present. As a
requirement of the City's previous NPDES Permit (Ecology, 1997), the City completed a
two-year effluent and receiving water study that began in January 1998 and ended in
December 1999, CH2M HILL presented that study's data in the report titled Additional
Chemical Analysis of Effluent and Receiving Water (CH2M HILL, 2000). Table 3 and
Table 4 present metals and conventional parameter summaries, respectively, from the
1998-1999 study. Ecology used data from the CH2M HILL report in calculating current
City NPDES permit limits for copper, lead, silver and zinc. Table 5 shows the effluent
copper, lead, silver and zinc levels measured under the requirements of the current
permit.
REV1
5
Metals(T=total, D=dissolved)
Conventionals
Sample
Location
As
Ag
Cd
Cr
Cu
Hg
Ni
Pb
Se
Zn
Alkalinity
hardness
pII
Temperature
Effluent
T,D
T,D
T,D
T,D
T,D
T,D
T,D
T,D
T,D
'1',D
X
X
X
X
Receiving
Water
T,D
T,D
T,D
T,D
T,D
T,D
T,D
T,D
T,D
T,D
X
X
X
X
Background
Existing Data
Existing clean metals data from the study sampling points are limited to measurements
from samples collected by City personnel between 1998 and the present. As a
requirement of the City's previous NPDES Permit (Ecology, 1997), the City completed a
two-year effluent and receiving water study that began in January 1998 and ended in
December 1999, CH2M HILL presented that study's data in the report titled Additional
Chemical Analysis of Effluent and Receiving Water (CH2M HILL, 2000). Table 3 and
Table 4 present metals and conventional parameter summaries, respectively, from the
1998-1999 study. Ecology used data from the CH2M HILL report in calculating current
City NPDES permit limits for copper, lead, silver and zinc. Table 5 shows the effluent
copper, lead, silver and zinc levels measured under the requirements of the current
permit.
REV1
5
Table 3. 1998-1999 Effluent and Receiving Water Clean Metals Summa
Table 4. 1998-1999 Effluent and Receiving Water Conventional Parameter Summa
Effluent
Metal Concentration in Micrograms per Liter (Total/Dissolved)
Effluent
As
Ag
Cd
Cr
Cu
Hg
Ni
Pb
Se
Zn
Mean
1.27/1.14
.652/.127
.160/.131
1.14/.840
12.4/5.71
.016/.004
2.19/1.60
1.28/.624
.881/.882
57.9/48.3
Range
.04-1.85
.015-1.07
.01-.294.
.07-1.85
.06-112
.002-.026
.04-4.99
.015-3.28
.05-2.22
.05-102
.223-1.8
.015-.392
.01-.224
.06-1.55
.58-8.73
.002-.012
.22-2.31
.015-.80
.05-1.86
.30-71.0
Receiving
Water
As
Ag
Cd
Cr
Cu
Hg
Ni
Pb
Se
Zn
Mean
.274/.232
.013/.013
.022/.022
.500/.136
.892/.421
.002/.002
.581/.248
.146/.021
.405/.398
1.41/.487
Range
.147-.51
.003-.026
.006-.044
.33-.70
.59-1.14
.001-.004
.10-1.57
.011-.281
.02-1.0
1.19-2.11
.147-.40
.01-.015
.005-.044
.06-.218
.33-.58
.0006-.008
.10-.57
.009-.032
.02-1.0
.20-.988
Table 4. 1998-1999 Effluent and Receiving Water Conventional Parameter Summa
Effluent
Alkalinity
(mg/L CaCO3)
Hardness
(mg/L CaCO3)
pH (SU)
Temperature
(C)
Mean
74.8
44.7
6.93
16.8
Range
40 - 111.8
18.7 - 83.7
6.00-7.80
10.0-24.5
Receiving
Water
Alkalinity
(mg/L CaCO3)
Hardness
(mg/L CaCO3)
pH (SU)
Temperature
(°C)
Mean
46.2
26.7
7.64
11.7
Range
30.0-90.0
15.0-44.8
6.10-8.00
6.30-21.0
RF
Table 5. 2003 Effluent Metals Monitoring Results
Total Metal Concentration in Micrograms per Liter
June
July
August
Ag
0.432
0.270
0.150
Cu
6.38
6.11
5.19
Pb
0.608
0.372
0.56
Zn
46.0
42.4
39.3
Sampling Design
Sampling Sites
Receiving Water
All receiving water samples for all parameters will be collected as grab samples from a
point 250 feet upstream of the effluent outfall structure (650 feet downstream of the
Highway 24 bridge) and approximately 6 feet from the shore. The samples will be taken
from a depth of three to six inches below the surface. This sample point was chosen for
several reasons. First, it is in the main channel of the river and will provide well -mixed
samples. Second, the distance upstream from the sample point to the effluent discharge
ensures that the sampling point is outside of the effluent's zone of influence. The
distance from the Highway 24 bridge minimizes potential sample contamination from
galvanized materials and automobile exhaust. Third, no identified point -source
discharges enter the river between the sampling point and the effluent outfall. This
ensures that measurements will accurately characterize the water that receives plant
effluent. Finally, since this sampling point is essentially identical to the receiving water
sampling point used in the 1998-1999 study, data users may make valid comparisons
between the current study and the prior study.
Effluent
All effluent samples for all parameters will be collected as grab samples at the effluent
outfall structure. The sampling point will be at the center of the downstream concrete
chamber (nearest the river) at a depth of three to six inches below the water surface. This
location represents the last accessible source of well -mixed effluent before discharge to
the river, ensuring that measurements will accurately characterize plant effluent
immediately before it enters the receiving water. In addition, since this sampling point is
identical to the effluent sampling point used in the 1998-1999 study, data users may make
valid comparisons between the current study and the prior study.
Field Procedures
Sample Collection
The collection and handling of all clean metal samples in this study will follow the City's
adaptation of EPA Method 1669 (USEPA, 1995), The City of Yakima Wastewater Plant
Clean Metal Sampling Standard Procedure (Appendix A). This standard procedure
reflects the strict contamination controls of the EPA guidance. These controls include the
use of protective sampling attire, the use of non-metallic sample collection equipment,
and the use of strict sample handling protocols. The City followed a similar standard
procedure during the 1998-1999 study and currently follows this standard procedure for
monthly monitoring of effluent metals (copper, zinc, silver, and lead). To date, equipment
blanks collected using this procedure at clean metals sampling events have shown no
detectable concentrations of target analytes.
REV 1
7
In summary, two sample team members use a peristaltic pump to collect clean metals
samples through a continuous length of polyethylene tubing directly into the sample
containers. The tubing, several pairs of non -powdered gloves, one gallon of equipment
blank water, and the sample containers are pre -cleaned in a class -100 clean room at
Frontier Geosciences (FGS), double -bagged, then shipped to the City. The samplers
wear hooded and booted tyvek suits, clean room gloves, and half -face respirators during
sample collection and sample handling.
The sample collection sequence for each quarterly sampling event will follow the outline
below:
1) First, at the receiving water sampling location, collect
a. Equipment blank total mercury sample, then
b. Equipment blank total metals sample, then
c. Total mercury sample, then
d. Dissolved mercury sample, then
e. Total metals sample, then
f. Dissolved metals sample, then
g. Alkalinity sample, then
h. pH sample, then
i. Hardness sample, then
j. Temperature sample.
Measure temperature immediately.
2) Second, within thirty minutes of completing receiving water sample
collection, at the effluent sampling location collect
a. Total mercury sample, then
b. Dissolved mercury sample, then
c. Total metals sample, then
d. Dissolved metals sample, then
e. Alkalinity sample, then
f. pH sample, then
g. Hardness sample, then
li. Temperature sample.
Measure temperature immediately.
Samplers will contain and treat study samples as detailed below in Table 6, Sample
Container, Preservation, and Holding Time Guide.
REVI
8
Table 6. Sample Container, Preservation and Holdin Ti
Parameter
eosci�� ao� will perform applicable fi
Method
Bottle
Preservation'
. v
�., Holding Time
Total Metals
EPA1638
250 ml HDPE
1-1NO3 to pH<2 within 48
hours. Cool to 4°C
6 months with preservation, 48 hours
without preservation
Dissolved Metals
EPA1638
250 ml HDPE
0.45um filtration within 48
hours, then immediate
HNO3 to pH<2. Cool to 4°C
6 months after filtration if pH< 2
Total Mercury
EPA1631
500 ml Glass
BrCI
28 days if preserved within 48 hours
Alkalinity
SM2320B.2
500 ml
polypropylene
Cool to 4°C
14 days
Hardness
SM2340B.
500 ml
polypropylene
HNO3 to pH<2 within 48
hours. Cool to 4°C.
6 months with preservation, 48 hours
without preservation
pH
SM4500-H+B.
500 ml
polypropylene
Cool to 4°C
24 hours
Temperature
Ir. Gr •
SM2550B.
500 ml
polypropylene
•
None. Analyze in field.
5 minutes. Analyze in field.
ltrations and preservations of metals and mercury samples upon sample
arrival at their laboratory (within 48 hours of sample collection). EPA Methods 1669 (USEPA, 1995), 1631 (USEPA,
2002) and 1638 (USEPA, 1996) recommend this protocol for dissolved and total mercury and for total metals. In an
effort to minimize field contamination, Frontier Geosciences extends this recommendation (Frontier, 2003) to the
filtration and preservation of dissolved metals samples, provided that samples are processed within 48 hours.
2SM refers to Standard Methods, 20 Edition (APHA, 1998).
Frontier Geosciences pre -labels each clean metals sample bottle at their laboratory with a
unique tracking number. Samplers will record this tracking number, sample name,
sample date, sample time, and requested parameters for each clean metals sample on the
Frontier Geosciences chain of custody document (Appendix B).
Temperature Measurement
The sampling team will measure the receiving water temperature inunediately from the
temperature sample bottle by immersing an alcohol -column thermometer. The
temperature will be read and recorded to the nearest tenth of one degree centigrade. All
other samples will be placed in a cooler with blue ice and returned to the City wastewater
laboratory. The clean metals samples and completed chain of custody will be shipped in a
cooler of blue ice via overnight courier service to Frontier Geosciences for appropriate
preservation, filtration, digestion, and analysis. The alkalinity, pH, and hardness samples
will be retained in a City laboratory refrigerator for preservation and analysis.
Laboratory Procedures
Each analytical method chosen for measuring study target parameters meets the
requirements specified in 40 CFR Part 136. Based on method -prescribed quality control
limits, each method has demonstrated acceptable performance in the study sample
matrices (CH2M HILL, 2000). Study laboratories demonstrate continued proficiency in
their assigned methods by maintaining current Ecology accreditation.
REVI
9
Table 7, Laboratory Procedures shows study parameters with associated methods,
preparation steps, detection limits, and performing laboratories.
Metals
FGS will analyze all total mercury samples by EPA Method 1631, and all other dissolved
and total metals samples by EPA Method 1638. These methods are specified in EPA
Method 1669 (EPA, 1995) as appropriate for the determining trace metals at water
quality criteria levels. Frontier's reporting limits for these methods easily meet project
requirements (Table 7).
Conventionals
The City wastewater treatment plant laboratory will perform all pH, alkalinity, and
hardness determinations by methods detailed in Standard Methods (APHA, 1992).
Table 7. Laboratory Procedures
Analyte
Method
Reference
Sample
Preparation
Required
Detection Limit
Laboratory
Reporting
Limit
Performing
Laboratory
Alkalinity
SM2320B.
--
10mg/L
YWWL
Hardness
SM2340B.
0.45um filter
-
5mg/L
YWWL
pH
SM4500-H`B.
--
-
YWWL
Dissolved Ag
EPA1638
0.45um filter
0.2 ug/L
0.015 ug/L
FGS
Dissolved As
EPA1638
0.45um filter
1.0 ug/L
0.05 ug/L
FGS
Dissolved Cd
EPA1638
0.45um filter
0.1 ug/L
0.01 ug/L
FGS
Dissolved Cr
EPA1638
0.45um filter
1.0 ug/L
0.07 ug/L
FGS
Dissolved Cu
EPA1638
0.45um filter
1.0 ug/L
0.04 ug/L
FGS
Dissolved Hg
EPA 1631
0.45um filter
0.2 ug/L
0.00015 ug/L
FGS
Dissolved Ni
EPA1638
0.45um filter
1.0 ug/L
0.04 ug/L
FGS
Dissolved Pb
EPA1638
0.45um filter
1.0 ug/L
0.015 ug/L
FGS
Dissolved Se
EPA1638
0.45um filter
2.0 ug/L
0.05 ug/L
FGS
Dissolved Zn
EPA1638
0.45um filter
2.0 ug/L
0.10 ug/L
FGS
Total Ag
EPA1638
Oven digest
0.2 ug/L
0.015 ug/L
FGS
Total As
EPA1638
Oven digest
1.0 ug/L
0.05 ug/L
FGS
Total Cd
EPA1638
Oven digest
0.1 ug/L
0.01 ug/L
FGS
Total Cr
EPA1638
Oven digest
1.0 ug/L
0.07 ug/L
FGS
Total Cu
EPA1638
Oven digest
1.0 ug/L
0.04 ug/L
FGS
Total Hg
EPA1631
SnC1
0.2 ug/L
0.00015 ug/L
FGS
Total Ni
EPA1638
Oven digest
1.0 ug/L
0.04 ug/L
FGS
Total Pb
EPA1638
Oven digest
1.0 ug/L
0.015 ug/L
FGS
Total Se
EPA1638
Oven digest
2.0 ug/L
0.05 ug/L
FGS
Total Zn
EPA1638
Oven digest
2.0 ug/L
0.10 ug/L
FGS
REV1
10
Measurement Quality Objectives and Quality Control
Procedures
Accuracy and Bias
Temperature Measurement
City staff will verify field thermometer performance prior to each sampling event
(quarterly) by comparing field thermometer readings to the City's NIST -traceable
thermometer. The check will occur in the City laboratory using a vessel of reagent water
that is in the approximate temperature range expected in the field samples. Agreement
between the field thermometer and the NIST -traceable thennoineter within + 0.2°C will
be acceptable. If the difference exceeds this criterion, another suitable thermometer will
be used or field measurements taken with the thermometer will be adjusted based on the
QC check.
Sample Collection
Equipment blank collection and analysis will be used to evaluate the sampling system for
trace metals contamination. Once per sampling event for total mercury and total target
metals analysis, City staff will process aliquots of reagent water through the entire sample
collection sequence at the receiving water sampling site. Equipment blanks will be
collected from the reagent water vessel using the same equipment to be used for
subsequent receiving water and effluent sample collection. Before it leaves their
laboratory, Frontier Geosciences certifies the reagent water as being free of target
parameters in concentrations above the method detection limit. If subsequent equipment
blank analysis shows detectable concentrations of target metals, it is possible that the
contamination occurred during sample collection. Equipment blank concentrations that
are one tenth or less of the method reporting limit (Table 7) will be acceptable.
Matrix Effects
Matrix effects can bias analytical results or raise target analyte detection limits. Matrix
spike analysis, in which investigative samples are spiked in the laboratory with target
metals at one to five times their native concentrations and subsequently analyzed to
determine the percentage recovery of the spiked analytes, are used to assess matrix bias.
Results from matrix spike analyses performed during the 1998-1999 study showed that
the receiving water and effluent matrices did not interfere with target analyte recovery,
nor did they raise target analyte detection limits. As a continuing check on the study
matrices, this study will include at least one matrix spike for each total metal analyte
(including mercury) in both the receiving water matrix and in the effluent matrix. Matrix
spike recoveries within 25% of the true value will be acceptable.
Laboratory Procedures
At a minimum, study laboratories will perform and report method -prescribed procedures
to assess analytical accuracy and bias. These procedures include initial calibration
verifications (ICV), continuing calibration verifications (CCV), analysis of standard
reference materials (SRM), percent recovery analysis of matrix spikes (MS) and matrix
spike duplicates (MSD) and the analysis of procedural blanks (PB). The laboratory
REV1
11
quality control limits for the study methods shown in Table 8 will serve as the study
measurement quality objectives for analytical accuracy and bias.
Table 8. Laboratory Measurement Quality Objectives for Accuracy and Bias
Lab
Parameter
Analytical
Method
ICV/CCV/ PB
Frequency
PB
Limit
(ug/L)
'MS/MSD/SRM
Frequencies
ICV/CC V
MS/MSD/SRM
Recoveries
FGS
Arsenic
EPA1638
10%
1
5%
75-125%
FGS
Cadmium
EPA1638
10%
.03
5%
75-125%
FGS
Chromium
EPA1638
10%
0.1
5%
75-125%
FGS
Copper
EPA1638
10%
0.2
5%
75-125%
FGS
Lead
EPA1638
10%
0.02
5%
75-125%
FGS
Mercury
EPA1631
10%
0.001
5%
75-125%
FGS
Nickel
EPA1638
10%
0.04
5%
75-125%
FGS
Selenium
EPA1638
10%
1
5%
75-125%
FGS
Silver
EPA1638
10%
0,09
5%
75-125%
FGS
Zinc
EPA1638
10%
0.6
5%
75-125%
YWWL
pH
SM4500-H13.
10%
-
5%
+ .1 SU (SRM)
YWWL
Alkalinity
SM2320B.
10%
-
5%
75-125% (SRM)
YWWL
Hardness
SM2340B.
10%
-
5%
75-125% (SRM)
'FGS SRMs are National Institute of Standards 1640 and 641d, or equivalents, for trace metals
and mercury, respectively. YWWL will check method performance with commercially prepared
materials from Analytical Products Group, Belfonte, PA.
Precision
Field Procedures
The City will evaluate sampling precision using field duplicates. Field duplicates are
commonly collected by splitting a water sample into two or more sample containers.
Based on contamination concerns, this procedure is not prudent when collecting water
samples for trace metals analysis. For the purposes of this study a field duplicate will be a
sample collected immediately after an investigative sample and submitted to the
laboratory for analysis by the same method(s) as the investigative sample.
Over the course of the study, the sampling team will collect at least one field duplicate
sample per sampling site for each site parameter. Relative percent differences (RPDs) of
less than 25 between the investigative sample result and the field duplicate result will be
acceptable.
Laboratory Procedures
At a minimum, study laboratories will perform and report method -prescribed procedures
to assess analytical precision. These procedures include matrix duplicate (MD) sample
analysis and matrix spike/matrix spike duplicate analysis (MS/MSD). The laboratory
quality control limits for the study methods shown in Table 9 will serve as the study data
quality objectives for analytical precision.
REVI
12
•3tory Measut•emeut Quality Objectives for Precision
1 [l R/la+ l• +�aa
Laboratory
•✓va [
Parameter
Analytical
Method
MD/MS/MSD
RPD
MD/MS/MSD
Frequency'
FGS
Arsenic
EPA1638
+ 25%
1 per 20 samples
FGS
Cadmium
EPA1638
± 25%
1 per 20 samples
FGS
Chromium
EPA1638
+ 25%
1 per 20 samples
FGS
Copper
EPA1638
+25%
1 per 20 samples
FGS
Lead
EPA1638
+ 25%
1 per 20 samples
FGS
Mercury
EPA 1631
+ 25%
1 per 20 samples
FGS
Nickel
EPA1638
± 25%
1 per 20 samples
FGS
Selenium
EPA1638
± 25%
1 per 20 samples
FGS
Silver
EPA1638
± 25%
1 per 20 samples
FGS
Zinc
BPA1638
+ 25%
1 per 20 samples
YWWL
pH
SM4500-WB.
+ .2 SU (MD)
1 per 20 samples
YWWL
Alkalinity
SM2320B.
+ 25% (MD)
1 per 20 samples
YWWL
Hardness
SM2340B.
+ 25% (MD)
1 per 20 samples
Frequency shown is routine laboratory minimum. At least one ea
with each batch of study samples.
Completeness
The City has established a target of 100% completeness based on permit requirements
(Ecology, 2003): the study will be considered complete after at least eight complete
parameter data sets have been compiled.
Comparability and Representativeness
In order to maximize comparability and representativeness, this study employs fixed
sampling sites, standardized field and laboratory procedures based on accepted guidance,
and specific data quality criteria. The selected procedures are consistent with the City's
prior receiving water and effluent study, and with current monthly effluent metals
monitoring. This will allow reasonable comparisons between data from this study, the
prior study, and current metals monitoring.
Data Analysis and Use
All field sample logs and laboratory data packages will be reviewed for completeness.
Study data will be compared to historic data ranges (Tables 3, 4 & 5). Improbable
analytical results, particularly those associated with unacceptable field or laboratory
quality control sample results, will be reviewed for qualification or rejection using EPA
inorganic data validation guidance (EPA, 2002) and EPA trace metals data validation
guidance (EPA, 1996b).
REV 1
13
In cases of rejected or missing data, the City may repeat a sampling event in order to
meet completeness goals. The City may increase the frequency of sampling events or
expand the target parameter list. The City will notify Ecology of study modifications with
a revised QAPP/SAP. Beginning in November 2004, and continuing through the course
of the study, the City will submit a complete summary of quarterly results from the most
recent sampling event to Ecology at least 15 calendar days before the next scheduled
sampling event.
Project Organization
The roles and responsibilities of study team members are as follows:
City of Yakima
• Doug Mayo, Wastewater Division Manager: Responsible for final document review,
communication with Ecology.
• Mike Price, Wastewater Division Laboratory Coordinator: Responsible for data
management including review, validation, and compilation. Responsible for
QAPP/SAP amendments and revisions, coordination of sampling events and
coordination with outside laboratories.
Frontier Geoscience
• Misty Kennard, Senior Project Manager. Submits completed metals analytical
reports and analytical narratives to the City. Coordinates shipment of sampling
equipment to the City.
Study Schedule
Table 10 shows the proposed study schedule:
Table 10. Proposed Schedule for the Receivin Water and Effluent Stud
Event
_ Date
Submit Draft QAPP/SAP for Ecology
Review
October 1, 2003
Finalize QAPP/SAP
June 1, 2004
First Study Sampling Event
September, 2004
Final Study Sampling Event
June, 2006
Submit Quarterly Results to Ecology
At least 15 days prior to next sampling event.
Submit Final Quarterly Results to Ecology
August 31, 2006
REVI
14
References
Ecology. 2003. NPDES Permit No. WA -002402-3 for the City of Yakima Regional
POTW. Washington State Department of Ecology, Central Regional Office. Yakima,
Washington.
Ecology. 1997. NPDES Permit No. WA -002402-3 for the City of Yakima Regional
POTW. Washington State Department of Ecology, Central Regional Office. Yakima,
Washington.
CH2M HILL. 2000. Additional Chemical Analysis of Effluent and Receiving Water.
CH2M HILL, Bellevue, Washington.
EPA. 1995. Method 1669: Sampling Ambient Water for Trace Metals at EPA Water
Quality Criteria Levels. EPA Publication No. 821-R-95-034.
Frontier Geosciences. 2003. Statement of Qualifications. (Available online at
http://www.fiontiergeosciences.com/frontierweb/)
EPA. 2002. Method 1631, Revision E: Mercury in Water by Oxidation, Purge and Trap,
and Cold Vapor Atomic Fluorescence Spectrometry.
EPA 1996a. Method 1638, Determination of Trace Elements in Ambient Waters by
Inductively Coupled Plasma — Mass Spectrometry.
EPA. 2002. National Functional Guidelines For Inorganic Data Review. EPA
Publication No.540-R-01-008.
EPA. 1996b. Guidance on the Documentation and Evaluation of Trace Metals Data
Collected for Clean Water Act Compliance Monitoring.
REV 1
15
Appendix A
The City of Yakima Wastewater Plant Clean Metal Sampling Standard
Procedure
Introduction
This procedure is based on Method 1669: Sampling Ambient Water for Trace Metals at
EPA Water Quality Criteria Levels (USEPA 821-R-95034, 1995). Method 1669 outlines
clean sampling techniques that preclude or minimize trace metal contamination.
The samplers, sampling equipment, and any other substance or object that contacts the
sample can introduce contamination. In this procedure, protective clothing and
respirators provide a barrier between the sampler and the sampling equipment, and
between the sampler and the sample(s). Non-metallic pre -cleaned sample collection
equipment minimizes trace metal contamination. Further, the sequence of sample
collection events will minimize trace metal cross contamination between sampling sites.
Finally, equipment blank collection and analysis should identify procedural or
operational deficiencies that may introduce trace metal contamination.
General Guidelines
Sample and Equipment Handling
All equipment and sample vessels that will contact the sample water is pre -cleaned in a
clean room at the laboratory and has been demonstrated to be free of metals
contamination. Sampling teams should take the following measures in order to maintain
this level of cleanliness and thereby minimize water sample contamination:
• Wear all clean sampling attire when handling clean equipment and water samples.
• Change clean gloves if you know or suspect that you have handled or touched dirty,
dusty, or metallic surfaces.
• Collect water samples only from the clean tubing directly into the sample bottle.
• Rinse the exterior surface of the clean tubing thoroughly with equipment blank water
if the clean tubing has touched a dirty or dusty surface.
Sample Collection Sequence
At any sampling event, collect the equipment blank first. Collect the equipment blank at
the first sampling site for that sampling event. One equipment blank per sampling event
should be adequate if the sample collection team samples the sites in order of
demonstrated or expected ascending metals concentrations. However, if relative metals
concentrations between two sampling sites are unknown or if sites are sampled out -of -
order, the team should replace the clean tubing between the sites and collect another field
blank at the next sampling site.
In general, locations are sampled in the order of demonstrated or expected ascending
metals concentrations. If river, effluent, and influent samples are required on the same
REVI
16
day, the river sample(s) will be collected first, the effluent sample(s) will be collected
second, and the influent sample(s) will be collected last.
If a single stream must be sampled from more than one location, the locations should be
sampled in the order of demonstrated or expected ascending metals concentrations. For
example, if river locations both upstream and downstream of the effluent discharge must
be sampled, the upstream location(s) should be sampled first.
Sample Collection Sites
Note on Sampling Sites
All sample collection sites should provide water samples that are representative
of the well -mixed stream.
River Sampling Site(s)
Study objectives will determine the river sampling sites. The identifying name of a river
sampling location will remain consistent for a given study and the location of that site
will remain accurate to within twenty meters for the duration of the study. Any river
sampling site should be in the main channel of the river, at least six feet from the shore
and at least three inches below the surface. Ambient water outside of the effluent's "zone
of influence" will be sampled at least one hundred feet upstream of the effluent
discharge. Mixed receiving water will be sampled at some distance downstream of the
effluent discharge. Simulated mixed receiving water will be prepared by combining
upstream ambient water and effluent in the correct proportions.
Effluent Sampling Site
The effluent sampling point should be at the effluent outfall structure near the Yakima
River. Sample the effluent from the center of the concrete chamber nearest the river,
three to six inches below the surface of the water.
Influent Sampling Site
The influent sampling point should be immediately downstream of the two major influent
pipes in the plant headworks building. Sample from the center of the concrete chamber
immediately upstream from the barscreen channel split, three to six inches below the
surface of the water. Note that this sample location does not include contributions from
the City's Industrial Waste collection system.
Procedure
Equipment
Verify that sampling equipment and supplies (Figure 1) are loaded in the vehicle. Note
that all equipment that will contact the sample water is pre -cleaned in a clean room at the
laboratory and has been demonstrated to be free of metals contamination. Use of
alternate materials is allowed if equipment blank analysis demonstrates that the alternate
materials are free of metals contamination.
REV
17
Sample Collection
Upon arrival at the sampling site, record the weather conditions on the sampling log
(Figure 2). Don the clean sampling attire (Figure 1).
REVI
Position the clean tubing in the sampler peristaltic mechanism.
Taking care at all times not to allow the end ten inches of the clean tubing to
contact any object, remove about eighteen inches of one end of the clean tubing
from the plastic bag. Allow the remainder of the tubing to stay in the bag.
Position this end section of tubing in the peristaltic mechanism. This maneuver
must be completed without touching the end ten inches of the tubing to the hands
or the peristaltic mechanism.
Affix the clean tubing to the guide pole.
Remove the remainder of the clean tubing from the plastic bag. Do not touch the
end twelve inches of the clean tubing and do not allow this section to contact any
other object. Rest the end of the guide pole that will be nearest the peristaltic
pump on the inside of the plastic bag that previously contained the clean tubing.
Beginning at the end of the guide pole that will be suspended directly above the
sample stream, begin attaching the clean tubing to the guide pole. Allow between
six and ten inches of the clean tubing to overhang the end of the guide pole. Use
at least four plastic cable ties to attach the clean tubing to the guide pole: one tie
three inches above the bottom of the guide pole, one tie eighteen inches up the
guide pole, one tie three feet up the guide pole, and one tie about five feet up the
guide pole.
Equipment Blank
One team member (Controller) will control the peristaltic pump and collect the
sample in the sample bottle while the other team member (Sampler) places the
sampling end of the clean tubing into the reagent water vessel.
After submerging at least three inches of the clean tubing into the reagent water
vessel, the Sampler will signal the Controller to start the pump. The Controller
end of the clean tubing should be hanging freely from the peristaltic mechanism
and should not be touching any object. A two -gallon plastic pail should be on the
ground beneath the Controller end of the clean tubing. Water will continue to run
through the clean tubing while the Controller is rinsing the sample bottle. The
plastic pail will catch and contain this water. Otherwise, the water will splash on
the ground or on the concrete pad during the rinse and potentially carry
contaminants from the pad into the nearby sampling point, onto the Controller end
of the clean tube, or into the uncapped sample bottle.
Rinse the Blank sample bottle
The Controller will fill and then empty the blank sample bottle into the
plastic pail, three times, with the reagent water that has been pumped
through the clean tubing. The Controller will leave the pump running
during the entire rinse process.
18
REV l
Collect the Equipment Blank
After rinsing the blank sample bottle three times, the Controller will fill
the bottle a final time with reagent water. When the blank sample bottle is
full, the Controller will signal the Sampler to remove his end of the clean
tubing from the reagent water vessel. The Controller will leave the pump
running in order to empty the tubing of any reagent water, collecting this
remaining water in the plastic pail. The Controller will then cap the bottle
and place it within the inner clean bag. The Controller will seal both the
inner clean bag and the outer bag, record the sample bottle identification
number (provided by the laboratory), the sample name, time, and date on
the chain of custody. The Controller will then place the double -bagged
blank sample in the cooler.
River, Effluent, or Influent Sample
Note on Effluent Sampling
Upon arrival at the outfall structure, unlock the chain-link gate and open the
grate above the effluent duct in order to allow washout of any particulates
dislodged from the grate or the grate frame. Avoid scuffing the cement pad with
shoes. When positioning the sampling equipment and materials onto the outfall
structure pad, place the equipment far enough away from the grate so that
particulates are not brushed or scraped into the effluent stream.
Rinse the Sample Bottle
Taking care not to allow his end of the clean tubing to contact any object,
the Sampler will maneuver the sampling pole and attached clean tubing
over the sample point. The Controller should retrieve the double -bagged
sample bottle from the cooler and remove the sample bottle from the inner
clean bag. Taking care not to allow his end of the tubing to contact any
object,. the Sampler will lower the guide pole and attached clean tubing
into the sampling position. The pole should be lowered to the point where
three to six inches of the clean tubing end is submerged in the stream. Do
not submerge the end of the guide pole in the stream.
When the end of the clean tubing is properly submerged in the stream, the
Sampler will signal the Controller to start the pump. After allowing the
pump to run for at least three minutes, the Controller will fill and empty
the sample bottle three times with sample water from the clean tubing.
The pump should be left on during and after the three bottle rinses. A two -
gallon plastic pail should be on the ground beneath the Controller end of
the clean tubing. Water will continue to run through the clean tubing
while the Controller is rinsing the sample bottle. The plastic pail will
catch and contain this water. Otherwise, the water will splash on the
ground or on the concrete pad during the rinse and potentially carry
contaminants from the pad into the nearby sampling point, onto the
Controller end of the clean tube, or into the uncapped sample bottle.
19
Collect the Sample
After rinsing the sample bottle three times with water from the clean
tubing, the Controller will fill the sample bottle a final time with sample
water. When the sample bottle is full, the Controller will signal the
Sampler to remove his end of the clean tubing from the stream. The
Controller will leave the pump running in order to empty the tubing of any
remaining sample water, collecting this remaining water in the plastic pail.
The Controller will then cap the bottle and place it within the inner clean
bag. The Controller will seal both the inner clean bag and the outer bag,
record the sample bottle identification number (provided by the
laboratory), the sample name, time, and date on the chain of custody. The
Controller will then place the double -bagged sample bottle in the cooler.
Sample Handling and Shipment
After collecting the final sample, return to the plant administration building and complete
the chain of custody document. Specify analytes, analytical method, analyzed fraction,
and any special result turn -around -time requirements. Notify FED EX or other overnight
carrier that a pick-up and delivery is required. Specify overnight express or next business
day delivery on the carrier document. Record the carrier tracking number on the chain of
custody. Retain copies of the completed chain of custody and the completed carrier
shipment request in the metals monitoring binder along with the completed sample logs.
Ensure that the sample cooler is packed with frozen blue ice, the water samples, and a
completed chain of custody. Make arrangements to ensure that the cooler will be picked
up and delivered. Fed Ex or UPS deliveries should be tracked on the internet to assure
timely delivery.
REVI
20
Figure 1
YAKIMA WASTEWATER PLANT CLEAN METALS EQUIPMENT AND
SUPPLIES
ATTIRE: TYVEK SUIT WITH HOOD AND BOOTIES
LAB SAFETY SUPPLY CATALOG
#14738M (MEDIUM)
#14738L (LARGE)
#14738XL (XL)
HALF -FACE RESPIRATOR
LAB SAFETY SUPPLY CATALOG #2BF-7210
HEPA RESPIRATOR CARTRIDGES
LAB SAFETY SUPPLY CATALOG #2BF-41590
GLOVES
FRONTIER GEOSCIENCES PROVIDES CLEANED GLOVES
SAMPLER: ISCO PORTABLE PERISTALTIC PUMP SAMPLER
YWWTP PRETREATMENT DEPARTMENT
GUIDE POLE: 12 FOOT LENGTH OF 1" DIAMETER WHITE PVC PIPE
TUBING:
COOLER:
BOTTLES:
BLANK:
BLUE ICE:
CH -O -C:
SHIPPING:
MISC:
REV 1
20 FOOT LENGTH OF MASTERFLEX 96410-73 (3/8" ID, 9/16"OD)
FRONTIER GEOSCIENCES PROVIDES CLEANED TUBING
FRONTIER GEOSCIENCES PROVIDES COOLER
FRONTIER GEOSCIENCES PROVIDES CLEANED BOTTLES
250m1 polyethylene for total or dissolved trace metals
500m1 glass for mercury
BOTTLE OF LABORATORY WATER
FRONTIER GEOSCIENCES PROVIDES A 1 GALLON BOTTLE(s)
OF EQUIPMENT BLANK WATER
YWWTP LABORATORY FREEZER
FRONTIER GEOSCIENCES PROVIDES CHAIN OF CUSTODY
FEDEX OVERNIGHT TO FRONTIER GEOSCIENCES, 414 PONTIUS
AVE. N., SEATTLE, WA 98901
PADLOCK KEYS FOR PLANT GATES. 10 CABLE TIES TO
SECURE SAMPLE TUBING TO GUIDE POLE, BLANK CLEAN
METALS SAMPLING LOG SHEETS FROM CLEAN METALS
BINDER, PENS, WATCH.
21
Figure 2
CLEAN METALS SAMPLE COLLECTION LOG
DATE:
COLLECTORS: ATTIRE:
WEATHER:
TEMPERATURE:
CONDITIONS:
WIND:
SAMPLE COLLECTION:
LOCATION:
SAMPLE METHOD:
SAMPLER:
TUBING:
GUIDE POLE:
EST. DEPTH TO WATER SURFACE:
SAMPLE BOTTLES:
LOCATION
TYPE
SURFACE/SUBSURFACE
I.D.
TOT./DISS.
ANALYTES
RINSES
TIME
SAMPLER INITIALS:
REV1
22
SUPPORTING DOCUMENTS
Method 1669: Sampling Ambient Water for Trace Metals at EPA Water Quality Criteria
Levels (USEPA 821-R-95034, 1995).
Evaluating Field Techniques for Collecting Effluent Samples for Trace Metals Analysis
(USEPA 1998).
Guidance on the Documentation and Evaluation of Trace Metals Data Collected for
Clean Water Act Compliance Monitoring. (USEPA 1996).
REV1
23
REVI
Appendix B
Frontier Geosciences Chain -of -Custody
24
12/18/2003 11:29 5095756116
CITY OF YAKIMA •
WASTEWATER DIVISION
2220 East Viola
Yakima, Washington 98901
Phone: 575-6077. Fax (509) 575-6126
December 19, 2003
David Dunn
Water Quality Program
Department Of Ecology
Central Regional Office
15 W Yakima Avenue
Suite 200
Yakima, WA 98902
Re: Facility Plan extension
Dear Mr. Dunn:
YAKIMA WWTP PAGE 02/02
The City of Yakima's Wastewater Facility Plan is required to be submitted by January 1,
2004. In the process of revising the 2000 draft plan; to address your earlier comments,
we have decided to do a more comprehensive update of the entire plan. The update will
actually provide a better plan that addresses the current issues and prioritizes the
necessary work to be completed to provide the best treatment possible to our wastewater
treatment processes.
Our Engineers have been aggressively working to meet the January 1, 2004 deadline but
to complete the more comprehensive update we need to have an additional two months.
This in depth update to the plan will also roll the Wasteload Assessment and Schedule of
compliance -Scope of work into it. We respectfully request an extension on the due date
for the Facility Plan, Wasteload Assessment and Schedule of Compliance -Scope of Work
submittals until March I, 2004.
If you have any question regarding this request I can be contacted at (509) 575-6077.
Sincerely,.
den
Ut' " Engineer
Wastewater division
Cc: Kenyon Hunt, Black & Veatch
1994
12/23/2003 11:11 5095756116 YAKIMA WWTP
STATE Or WASHINGTON
DEPARTMENT OF ECOLOGY
15 West Yakima Avenue, Suite 200 • Yakima,,.Washin&tan 90902-3452 • (509) 575.2490
December 19, 2003
Max Linden
City of Yakima — Wastewater Division
2220 E. Viola
Yakima, WA 98901
RE: Wastewater Facility Plan: Permit Condition S.11.A,
PAGE 02/02
Your address •
Is In the
Lower
Yakima
watershed
Dear Mr. Linden:
Special condition 11.A, of the City's permit requires submittal of the Final Facility Plan by
January 1, 2004. This final plan is intended to address comments provided to the City regarding
the Draft Facility Plan submitted in 2000, The Department of Ecology (Department) has
received the City's request to extend this deadline to March 1, 2004. This change constitutes a
modification to the existing NPDES permit. The Department is unable to complete a formal
permit modification at this time due to constraints on staff time and our current volume of work.
The Department agrees to exercise prosecutorial discretion, allowing the City to submit the Final
Facility Plan by March 1, 2004. The exercise of prosecutorial discretion does not relieve the
permittee of any liability or obligation from 3rd party lawsuits that may result from violation of
its NPDES permit.
If you have any questions, please don't hesitate to contact me at 509-454-7845.
Very Truly Yours,
David C. Dunn, P.F.
Water Quality Program
DCD:cmx
SEPA and SERP Documentation
to be inserted
when complete
ae,L
y4.6, s --/-Y° p aj-
1-f OE PA vvYlAd--)4
City of Yakima
Metals Study
Scope of Work Report
Summary
This Metals Study Scope of Work Report was prepared in accordance with Section S13. Schedule
of Compliance, A. Scope of Work Report from the City of Yakima's NPDES Permit No. WA -
002402 -3, effective June 1, 2003. The purpose of the study is to investigate measures to be taken
to ensure that the effluent discharged from the Yakima Regional Wastewater Treatment Plant
achieves compliance with the State of Washington Surface Water Quality Standards, particularly
for Copper, Lead, Silver, and Zinc. The study will be conducted in up to six phases (some of
which are optional, dependent upon results of a prior phase), as follows:
• Phase I - Investigations
• Phase II - Sampling Domestic/Commercial Wastewater (optional based on information
from Phase 1.)
• Phase III - Analysis of Industrial and Domestic Sources (only if Phase II is required)
• Phase IV - Calculation of Headworks Loading
• Phase V - Mitigation Process
• Phase VI - Communication
Phase I - Investigations
Task 1. Review Historical Plant Data. Existing plant operational and laboratory data will be
reviewed to identify and review information regarding potential pollutants of concern. This task
will start with a project initiation meeting between ENGINEER and the City. During this meeting
project procedures and information sources will be discussed. It is anticipated that copies of the
following docutnents and information will be made available to the ENGINEER:
1. Previous local limits studies.
2. Mixing zone studies.
3. Existing NPDES permit.
4. Maps of the wastewater collection system showing location of key industrial users.
5. Existing Approved Pretreatment Program documents.
6. Sewer Use Ordinance.
7. EPA Audit Reports.
8. Recent schematic/process size information on treatment plant.
9. Plant operational information - flow and quality by unit process.
10. Plant conventional, metal and toxic organic data by unit process, including priority
pollutant scans of the influent and effluent for the wastewater treatment plant.
11. Residuals data for the wastewater treatment plant.
12. Industrial monitoring data (water quality and flow) for past two years.
13. Annual pretreatment reports for past two years.
14. Portions of Master Planning Documents regarding future industrial growth in the area.
15. Domestic and commercial user monitoring data.
16. Metals Concentrations in service area potable water supply system(s).
Metals Study Scope of Work Report 1 DRAFT 02/26/04
Task 2. Review Mixing Zone Study. Information from the recent Mixing Zone Study will be
examined to establish dilution factors. These factors will be summarized by pollutant and used as
part of the headworks analysis.
Task 3. Review Industrial User Information. Information from industrial users will be assessed to
effectively determine the impacts of any local limit. A critical piece of information for the local
limits study is effluent flow from industrial users. Effluent flow is one of the parameters that may
be used to allocate the allowable industrial load to the industrial users. From the available
industrial data, ENGINEER will determine the total industrial flow to the treatment plant.
Task 4. Develop Pollutants of Concern. Pollutants of concern (POC) are those pollutants that have
the potential to cause interference or pass through the treatment plant with limited removal.
USEPA has identified 15 POCs, including Cu, Pb, Ag, and Zinc, for which POTWs must establish
local limits. Each POTW can expand its POC list to include additional pollutants based upon its
industrial process, collection system, and customer base. Using the sampling data, an analysis will
be performed to identify any additional pollutants of concern.
Task 5. Pollutant of Concern Report. Based on the results of the POC analysis, ENGINEER will
prepare a memorandum that summarizes the following:
1. Data deficiencies.
2. Results of a preliminary pollutant of concern analysis prepared on existing data.
3. Results of a preliminary headworks mass balance based on existing treatment plant and
industrial monitoring data for each POC.
4. A list of additional POCs for consideration under the headworks loading analysis.
Copies of this memorandum will be delivered to the City for review and comment.
Phase II — Sampling Domestic/Commerical Wastewater (optional based on information from
Phase 1.)
Task 1. Determining Additional Sampling Requirements. Using the results of Phase 1, additional
sampling requirements will be developed for collection of required data.
Task 2. Development of a Monitoring Plan. A monitoring program plan will be developed that
details the specifics regarding the collection of samples for the local limits study. ENGINEER will
be responsible for administrating and coordinating the plan after it has been approved by the City.
Phase III - Analysis of Industrial and Domestic Sources (only if Phase II is required)
Task 1. Data Summary. Historical data and monitoring data collected under Phase II will be
analyzed to determine the respective pollutant loadings. Inconsistencies in the data will be
reported. Pollutant loading will be determined by source. Data will be summarized so that it can
be easily entered into a Headworks model for the calculation of local limits. All data for the local
limits calculation will be collected during this phase of the project. Activities necessary for the
development of the mass balance with industries will be coordinated.
Metals Study Scope of Work Report 2 DRAFT 02/26/04
Phase IV Calculation of Headworks Loading
Task 1. Develop Headworks Loading. A computer model will be used to establish the maximum
allowable headworks load for conventional pollutants, metals, and toxic POCs.
This analysis will consist of the following:
1. The treatment plant will be examined in accordance with EPA guidance.
2. Develop a list of specific limiting factors for each pollutant of concern.
3. Determination of applicable environmental criteria from which local limits will be
derived. These criteria include water quality standards; NPDES permit requirements,
literature values for plant process inhibition, and residual disposal requirements.
Removal efficiencies must be determined for each major treatment process using actual
sampling data.
4. Identify causes of possible inconsistencies between the measured plant loads and
industrial/commerical/domestic loads.
5. Calculation of allowable headworks loadings and concentrations from environmental
criteria and POC removal by treatment process.
6. Selection of the lowest (the most restrictive) of the allowable headworks loadings and
concentrations. This value is called the critical headworks loading or concentration.
7. Determine percentage of Headworks loading already used by domestic and unregulated
commercial users.
8. Determination of allowable industrial loading from critical headworks loads by
accounting for contributions from domestic sources and the application of a safety
factor.
Phase V — Mitigation Process
Task 1. Establishment of Target Pollutants. Using the results for Phase IV, a list of pollutants and
loadings will be determined that allows the wastewater treatment plant to be in compliance with
discharge requirements. These loadings will be used for evaluations conducted in Tasks 2, 3 and 4.
Task 2. pH (Corrosion) Control in the Water Supply. A desk -top review of existing water quality
data and corrosion control techniques to establish a preferred treatment technique will be completed
for all water sources. This evaluation will examine available alternatives, constraints to treatment
alternatives, and recommend optimal corrosion control techniques. Impacts to metal loadings
using the various alternatives will be developed. Capital and operational costs will be developed
for the various available alternatives.
Task 3. Source Reduction. Data from industrial, domestic, and commercial users will be examined
to determine potential sources of reduction. Estimated pollutant reduction and costs will be
developed for the top industrial users contributing the largest industrial pollutant loading.
Literature information will be used to assess pollutant removals that can be achieved using best
management practices. These practices have been shown to be effective in removing various
metals. Many communities have established household hazardous waste facilities to limit the
Metals Study Scope of Work Report 3 DRAFT 02/26/04
discharge of metal and toxic organic pollutants to the wastewater collection system. Cost and
pollutant removals from these types of facilities will be determined through a survey of
representative operational facilities.
Task 4. Treatment. Literature studies will be performed to screen a variety of treatment
technologies for the removal of targeted metal pollutants from the effluent of the Wastewater
Treatment Plant. Treatment processes which will be examined will include filtration (0.45 µm
and 0.1 pm), precipitation (hydroxide and sulfide), coagulation/flocculation (alum and ferric
chloride), ion exchange resins (four different resins), an adsorbent resin, and powdered activated
carbon (added to final clarifier effluent and the aeration basin). A summary of typical removal
efficiencies will be developed for each identified process. Capital and operational costs will be
developed for each process. Residual quantities for each process will also be determined along
with corresponding cost for residuals disposal.
Task 5. Mitigation Process Report. Based on the results of the evaluations, ENGINEER will
prepare a memorandum that summarizes the following:
• Cost and estimated pollutant reduction based on implementation of corrosion control.
• Cost and estimated pollutant reduction based on implementation of source reduction.
• Cost and estimated pollutant reduction based on implementation of treatment.
Copies of this memorandum will be delivered to the City for review and comment.
Phase VI — Communication
Task 1. Monthly Meetings. Conduct monthly meetings for information transfer and conduct
periodic briefings to inform City staff of the project status.
Task 2. Monthly Status Reports. Prepare status reports for review on a monthly basis. Status
reports will be submitted to the City one week before the scheduled status meetings.
Task 3. Presentations. ENGINEER will be available to make presentations with the City in
required meetings, including public meetings, meetings with industrial users, regulatory briefings,
etc. ENGINEER will be responsible for preparation of presentation materials (graphics and
handouts) and meeting notes for submission to the City.
Metals Study Scope of Work Report 4 DRAFT 02/26/04
City of Yakima
WWTP Mixing Zone Study
Prepared for:
City of Yakima
2220 E Viola
Yakima, Washington 98901
and
Black & Veatch
1111 3`d Avenue, Suite 3125
Seattle, Washington 98101-3299
Prepared by:
Cosmopolitan Engineering Group
117 South 8 Street
Tacoma, Washington 98402
September 2003
B&V007
TABLE OF CONTENTS
Page
SECTION 1: INTRODUCTION 1-1
SECTION 2: WATER QUALITY STANDARDS 2-1
2.1 Amended Water Quality Standards 2-1
2.2 Water Quality Criteria for Conventional Parameters 2-1
2.3 Water Quality Criteria for Toxicants 2-1
2.4 Mixing Zone Regulations 2-2
SECTION 3: STEADY-STATE DILUTION ANALYSIS 3-1
3 1 Critical River Flow 3-1
3.2 Critical Effluent Flows 3-4
3.3 Steady -State Dilution Factors 3-4
SECTION 4: CONTINUOUS SIMULATION MODEL 4-1
4.1 Dilution Model 4-1
4.2 Continuous Simulation for Ammonia 4-3
4.3 Continuous Simulation for Metals 4-6
SECTION 5: EFFLUENT LIMITS 5-1
5.1 Methodology and Results 5-1
5.2 Recommended Water Quality -based Effluent Limits for the Current NPDES
Permit 5-3
5.3 Projected Water Quality -based Effluent Limitations at Buildout 5-4
SECTION 6: FUTURE BASIN -WIDE WATER QUALITY ISSUES 6-1
6.1 303(d) Listings 6-1
6.2 Temperature 6-2
6.3 Biochemical Oxygen Demand 6-3
6.4 Phosphorus 6-4
SECTION 7: REFERENCES 7-1
City of Yakima B&V007
IVIVTP Effluent Mixing Zone Study i September 2003
LIST OF TABLES
Page
Table 1 Conventional Water Quality Criteria for the Yakima River 2-1
Table 2 Toxicant Water Quality Criteria for the Yakima River 2-2
Table 3 River Discharge Statistics for Mixing Zone Study 3-3
Table 4 Critical Steady -State Effluent Flow Rates for Mixing Zone Study 3-4
Table 5 Steady -State Dilution Factors 3-5
Table 6 Summary of Alternative Dilution Factors and Corresponding Effluent
Limitations 5-2
Table 7 Recommended Effluent Limits for the Current NPDES Permit 5-3
Table 8 Projected Buildout Effluent Limits 5-4
Table 9 Analysis of Temperature Impact 6-2
LIST OF FIGURES
Page
Figure 1 7 -Day River Discharge Statistics, Yakima River near Yakima (Source: BOR) 3-3
Figure 2 Ambient Ammonia -N Data 4-4
Figure 3 Ambient pH Data 4-5
Figure 4 Ambient Temperature Data 4-5
Figure 5 Effluent and Ambient Hardness Data 4-7
LIST OF APPENDICES
Appendix A: Permit Limit Worksheets
13& V007
City of Yakima
Ir'w September 2003
P Effluent Mixing Zone Study ii
SECTION 1:
INTRODUCTION
The NPDES permit for the City of Yakima WWTP dated April 30, 2003, includes water quality -
based effluent limits for anunonia and metals, which were calculated using the default wasteload
allocation methods described in Ecology's Permit Writer's Manual (Ecology Publication No. 92-
109). Dilution factors and water quality -based effluent limits for the City of Yakima have been
re -calculated in this report using various advanced modeling methods. The advanced modeling
methods are based on the mixing zone regulations in WAC 173-201A, and supported by
Ecology's Permit Writer's Manual and EPA's Technical Support Document for Water Quality -
based Toxics Control (EPA 505/2-90-001). The purpose of using these methods is to
successively strip away layers of conservative assumptions implicit in Ecology's default
methods, in order to develop statistically robust effluent limits that more closely meet the water
quality criteria in WAC 173-201A.
The alternative mixing zone modeling methods presented in this paper include the following:
• Annual steady-state (default method used in existing NPDES permit)
• Annual steady with revised 7Q10 calculation
• Seasonal steady-state
• Annual steady-state under variance criteria allowed in WAC 173-201A
• Continuous simulation wasteload allocation modeling (annual)
• Continuous simulation wasteload allocation modeling (seasonal)
The primary purpose of this report is to present the alternative dilution modeling and effluent
limits for anunonia and metals. The continuous simulation modeling, in particular, includes a
large number of detailed and linked calculations performed on spreadsheets. Thus, it is
impractical to provide complete printouts of the modeling results. All modeling calculations
described in this report are archived on a companion CD entitled Yakima WWTP Mixing Zone
City of Yakima B&V007
111I17P Effluent Mixing Zane Study 1-1 September 2003
Modeling and Water Quality -based Effluent Limits by Cosmopolitan Engineering Group dated
August 2003.
There are also water quality concerns in the Yakima River that extend beyond the mixing zone,
and include the comprehensive water quality effects of all discharges to the watershed. The
current regulatory status, water quality planning and modeling requirements, and the
implications of these broader water quality issues on future Yakima WWTP effluent limitations
are discussed in this report.
City of Yakima B& V007
WWTP Effluent Mixing Zone Study 1-2 September 2003
SECTION 2:
WATER QUALITY STANDARDS
2.1 AMENDED WATER QUALITY STANDARDS
The Water Quality Standards (WAC 173-201A) were recently amended on July 1, 2003. The
principal change was to move from a classification system to a use -based system. The Yakima
River from its mouth to Cle Elum was classified A (Excellent) in the old standards. Under the
new standards, the same reach is designated for non-core salmon and trout spawning and rearing,
primary contact recreation, and a variety of water supply and miscellaneous uses (WAC 173-
201A-602). Based on these amended designated uses, the mixing zone rule and water quality
criteria have not changed. Therefore, the recent change in water quality standards will not affect
the City of Yakima WWTP effluent limits.
2.2 WATER QUALITY CRITERIA FOR CONVENTIONAL PARAMETERS
The water quality criteria for conventional water quality parameters affected by WWTP effluent
are summarized in Table 1.
Table 1 Conventional Water Quality Criteria for the Yakima River
Conventional Parameters
Criteria
Dissolved Oxygen
Shall exceed 8.0 mg/L
Temperature
Shall not exceed 21°C. No human increase above 34/ (T+9)
Fecal Coliform
Geo. mean —100 colonies/100 mL
90th percentile — 200 colonies/100 mL
pH
6.5 to 8.5
2.3 WATER QUALITY CRITERIA FOR TOXICANTS
Toxic substances typically present in municipal wastewater effluent include ammonia, chlorine,
and metals. Ecology's recently renewed NPDES permit for the City of Yakima WWTP
established the following metals as having a reasonable potential to exceed water quality
standards: copper, lead, silver and zinc.
City of Yakima 13&17007
If'IE'TP Effluent Mixing Zone Study 2-1 September 2003
The criteria for ammonia are dependent upon the receiving water pH and temperature, and the
metals criteria are dependent upon hardness at the mixing zone boundaries. Ecology's default
methods of assessing compliance with water quality standards specifies that the toxicant criteria
be based on critical 10th or 90th percentile values for temperature, pH and hardness. The criteria
for toxic substances of concern based on these conservative ambient values are listed in Table 2.
Table 2 Toxicant Water Quality Criteria for the Yakima River
Toxic Parameters
Acute Criteria
(AWL)
Chronic Criteria
(}►g/L)
Anunonia-N
17,800
1,480
Chlorine
19
11
Copper
5.38
3.28
Lead
16.7
0.50
Silver
0.42
—
Ziic
40.6
30.6
2.4 MIXING ZONE REGULATIONS
Mixing Zone Definition. The water quality standards allow the use of mixing zones, with
conditions, for NPDES permitted discharges. A mixing zone is a volume of a receiving water
where mixing results in the dilution of the effluent with the receiving water. If a mixing zone is
allowed by Ecology, compliance with the water quality standards is required at the boundary of
the mixing zone (WAC 173-201A-400(5)).
Mixing Zone Criteria (Chronic Mixing Zone). WAC 173 -201A -400(7)(a) specifies the
maximum size of a mixing zone. For a discharge into a river, the nixing zone where
conventional parameters and chronic toxicity criteria apply shall comply with the most restrictive
combination of the following:
1. Not extend in a downstream direction for a distance from the discharge port(s) greater
that 300 feet plus the depth of water over the discharge port(s)
2. Not utilize greater than 25 percent of the flow, and
3. Not occupy greater than 25 percent of the width of the water body
City of Yakima B&i'007
N'lf'TP Effluent Mixing Zone Study 2-2 September 2003
Acute Mixing Zone Criteria. WAC 173-201A-100(8) allows conditional acute criteria
exceedence. Similar to application of chronic criteria, a zone where acute criteria may be
exceeded must comply with the most restrictive combination of the following:
i. Not extend beyond 10 percent of the distance towards the upstream and downstream
boundaries of an authorized chronic mixing zone, as measured independently from the
discharge port(s)
ii. Not utilize greater than 2.5 percent of the flow, and
iii. Not occupy greater than 25 percent of the width of the water body
Existing Mixing Zone Dimensions. The City of Yakima's NPDES permit specifies acute and
chronic mixing zone boundaries of 31 and 310 feet, respectively, downstream of the diffuser.
The acute and chronic dilution factors specified in the permit are 1.51 and 6.61, respectively.
Mixing Zone Variance Provisions. The water quality standards allow Ecology to consider
exceedences of the mixing zone numeric size criteria described above, with the following
stipulations:
i. The discharge existed prior to November 24, 1992
ii. Altering the size configuration is expected to result in greater protection to existing
and characteristic uses
iii. The discharge provides a greater benefit to the existing or characteristic uses of the
water body due to flow augmentation than the benefit of removing the discharge if
removal of the discharge is the remaining feasible option, or
iv. The exceedence is necessary to accommodate important economic or social
development in the area
The Yakima WWTP discharge satisfies these criteria on the basis of part (i) alone, having existed
long before 1992. Before approval of an exceedence of the mixing zone size criteria, Ecology
must be satisfied that:
City of Yakima B&Y007
TYH'TP Effluent Mixing Zone Study 2-3 September 2003
i. The discharge receives treatment consistent with AKART
ii. The discharger utilizes all economically achievable siting, technology, and
managerial options that result in full or significantly close compliance, and
iii. The supporting information clearly indicates the mixing zone would not have a
reasonable potential to cause a loss of sensitive or important habitat, substantially
interfere with the existing or characteristic uses of the water body, result in damage to
the ecosystem, or adversely affect public health
The Yakima WWTP clearly meets AKART provisions. Sub -parts ii and iii would require
subjective determinations by Ecology in order to qualify for an exemption.
If Ecology grants an exemption to the size criteria, the exemption shall be reexamined during
each renewal of the NPDES permit. In this report, one of the alternatives includes assessment of
dilution under these variance provisions. The City would be seeking a variance only for the
chronic and acute criteria that are based on percentage of ambient flow. The physical mixing
zone dimensions of 31 feet (acute) and 310 feet (chronic) would not be altered.
City of Yakima B&V007
1VIYTP Effluent Mixing Zone Study 2-4 September 2003
SECTION 3:
STEADY-STATE DILUTION ANALYSIS
Ecology's default mixing zone methodology is based on steady-state analysis. That is, all
parameters that influence dilution factors, water quality criteria, and compliance with standards
are at constant, critical values. This section of the Mixing Zone Study assesses dilution factors
calculated for steady-state conditions using several alternative, less conservative methods.
3.1 CRITICAL RIVER FLOW
7Q10 River Discharge. Ecology's Permit Writer's Manual and WAC 173-201A specify use of
the 7 -day low flow with a 10 -year recurrence interval (7Q10) for the development of critical
steady-state dilution factors. 7Q20 flows are used for semi-annual seasonal limits for equivalent
risk. Ecology calculated the 7Q10 for the Yakima River near Yakima to be 632 cfs based on
historical data from USGS and the Bureau of Reclamation (BOR). This figure is documented in
the Fact Sheet for the City's NPDES Permit. As part of this Mixing Zone Study, Cosmopolitan
Engineering confirmed that Ecology's calculation of the historical 7Q10 was correct.
Watershed Flow Management Changes. BOR has taken over responsibility for stream gauging
in the Yakima Basin from USGS because of their control of the reservoir system m the upper
watershed. The low flow regime in the upper basin is and has been heavily controlled by these
reservoirs. However, operation of the dams has changed significantly in recent years for
fisheries protection. Therefore, historic 7Q10 statistics are no longer relevant to current and
binding policies established by BOR and fisheries interests relative to minimum instream flows.
River discharge requirements have been developed as part of the Yakima River Basin Water
Enhancement Program (YRBWEP), and the Total Water Supply Available (TWSA) evaluations.
These requirements are developed and published annually by BOR, which operates the five
upstream reservoirs. Clearly, the historic 7Q10 river discharge is not relevant under the
contemporary in -stream flow requirements established by YRBWEP. Since the Yakima River is
tightly controlled, and operational criteria have changed significantly, the historic 7Q10 will not
be used as the basis for this mixing zone analysis. In this situation, selection of critical flow rate
for the mixing zone analysis falls within Ecology's discretion.
City of Yakima B&1'007
1V117P Effluent Miring Zone Study 3-1 September 2003
In January 1997, Ecology's Watershed Assessments Section published a guidance document
titled TMDL Development Guidelines, 112 River Critical Low Flows. The following discussion is
included in the guidance document under the heading "Consideration of streams affected by
dams and/or minimum instream flows:"
Streanow in many streams is affected by dams and/oi• agreements on rnininrum
instream flows. These limitations on stream/low arise from many sources,
including minimum flows set by regulation, section 401 certifications, interagency
agreements, limits on individual water rights, Corps of Engineers operation rules,
etc.
The critical flow to be used in these cases is still a low flow that represents a risk
equivalent to the 7Q10. The critical low flow, however, should also reflect
anticipated conditions in the stream, which will not always be consistent ii'ith the
historical record. Thus, the critical low flow analysis should include both the
calculated 7Q10 and any minimum flow requirements; the hydrologic history of
the river or stream; the reliability of the nrininnrm flow (that is, the consistency of
flows or strength of the legal instrument controlling the flows); and any trends or
other anticipated changes inflows for the future.
Revised 7Q10 Calculation. Daily river discharge at the Yakima WWTP is determined as a
function of four gauging sites maintained by BOR. Daily discharge statistics were obtained from
BOR, and are included in "Yakima Dynamic Model.xls" in the "River Q" spreadsheet. The
Naches gauge was down for approximately 7 months in 2001, and conservative data were
interpolated for this period.
Water years 1993 (e.g., October 1992 through September 1993) and 1994 were the last that
included low river discharges on the order of 600 cfs. Because of the changes in low -flow
management in the watershed, the 7Q10 and 7Q20 (used in seasonal limits) river flow statistics
are calculated only from discharge data beginning in water year 1995. The 7 -day averages since
1993 are shown in Figure 1, which illustrates the changes in low flows since 1995.
City of Yakima B&V007
MI/7'P Effluent Miring Zone Study 3-2 September 2003
4000
3500
3000
2500
`e 2000
0
Li LL
1500
2
1000
500
0
7 -Day Average Flows
------..
Flow (cfs)
Historic 7Q10
•
♦
• •
• • "t • • i
1994-2003 Oct -Mar 7Q20
•
1995-2002 Apr -Nov 7Q20
-♦ ♦
•
•
♦ •
•
•
•
V'• to■•■• N
TI
••—
'■
•
+♦—•
•
4
•
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.
'•i•.•
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• .+ • • •
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` ■ • s ■ ■ • • ■ is
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or • •
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1
I d
! [t
0
30
60
90
120
150
180 210
Julian Day
1e 1993 -1994 .1995 - 20031
Figure 1
240
270
300
330
360
7 -Day River Discharge Statistics,
Yakima River near Yakima
(Source: BOR)
Beginning in row 3659, the "River Q" spreadsheet includes a calculation of the 10th percentile
for annual minima of 7 -day flows using several methods. Fifth percentile statistics, which are
required by Ecology for split -season assessments, are also assessed. The results, which are used
in this mixing zone modeling for critical steady-state modeling, are presented in Table 3.
Table 3 River Discharge Statistics for Mixing Zone Study
Discharge Statistic
Flow (cfs)
Historic 7Q10
632
1995-2003 7Q10
908
1994-2003 Oct -Mar 7Q20
899
1995-2002 Apr -Nov 7Q20
1909
City of Yakima
WWTP Effluent Miring Zone Study 3-3
B& V007
September 2003
3.2 CRITICAL EFFLUENT FLOWS
Ecology's Permit Writer's Manual specifies that steady-state mixing zone analyses for NPDES
permits be conducted at the highest actual monthly average during the past 3 years for
conventional parameters and chronic toxicants. The highest actual daily flow must be used for
acute toxicants. These statistics were determined by Ecology from DMRs submitted by the City
of Yakima, and are cited in the NPDES Permit Fact Sheet. The critical flows specified by
Ecology protocol are listed in Table 4. The seasonal differences in effluent flow peaks are
nominal, so the annual values are also used in seasonal modeling.
Table 4 Critical Steady -State Effluent Flow Rates for Mixing Zone Study
Flow Condition -
Model Application
Flow Rate
Maximum Month
Chronic
18.3 mgd
Maximum Day
Acute
20.0 mgd
3.3 STEADY-STATE DILUTION FACTORS
RIVPLUM Model. RIVPLUM is a mixing zone model applicable to river discharges, supported
by Ecology in the Permit Writer's Manual, and was used in the development of the current
NPDES permit. The "RIVPLUM5" spreadsheet in "Yakima Dynamic Model.xls" calculates
daily RIVPLUM calculations. The ambient velocity and depth are modified from the values
measured by HDR in their 1996 report to satisfy continuity principals (the revised velocities and
depths are conservatively lower).
Acute and Chronic Dilution Factors. Dilution factors have also been calculated using the 2.5
percent of ambient flow for the acute condition and 25 percent of ambient flow for the chronic
condition. The results are shown in Table 5. In all cases, the percentage limitations are more
restrictive than the RIVPLUM modeled dilution factors, and thus are to be used in water quality -
based limit calculations.
City of Yakima B&V007
!VIVTP Effluent Miring Zone Study 3-4 September 2003
Table 5 Steady -State Dilution Factors
Steady -State Condition
River
Discharge
(cfs)
RIVPLUM
Acute Dilution
23% Acute
Dilution
RIVPLUM
Chronic
Dilution
25% Chronic
Dilution
Existing NPDES
632
3.21
1.51
9.29
6.61
Revised Annual
908
4.16
1.74
13.18
9.07
Oct — Mar
899
4.13
1.73
13.06
8.99
Apr — Nov
1909
8.14
2.55
27.78
17.96
Effluent Flows = 30.78 cfs (20.0 mgd) for acute, 28.15 cfs (18.3 mgd) for chronic
The steady-state permit limit calculations will be based on the dilution values shown in the 2.5
percent column for acute, and the 25 percent column for chronic. However, as stated in the
introduction section, one alternative considered in this mixing zone study is a waiver from the
2.5 percent and 25 percent limitations. In this "variance" alternative the permit limits would be
determined on the basis of the RIVPLUM results only. Therefore, the revised annual dilution
factors would be 4.16 for acute and 13.18 for chronic.
City of Yakima B&V007
MU!' Effluent Mixing Zone Study 3-5 September 2003
SECTION 4:
CONTINUOUS SIMULATION MODEL
Steady-state modeling considers only a single condition for all independent parameters, which
are assumed to be constant. Conservative values are required to be used for all parameters. The
impact of natural variability in flows and water quality parameters is that effluent limits based on
steady-state modeling are implicitly very improbable. Conversely, dynamic modeling techniques
explicitly predict the effects of receiving water and effluent flow and concentration variability.
This technique allows for a more precise determination of effluent limits consistent with the
probability, duration, and frequency basis for the receiving water criteria (EPA, 1991).
The three dynamic modeling methods supported by EPA (1991) include continuous simulation,
Monte Carlo, and lognormal probability. Continuous simulation modeling uses daily effluent
and river flow and concentration data to calculate daily acute and chronic dilution factors,
ambient criteria, and wasteload allocations for parameters of concern. The critical daily
wasteload allocations are then used to establish effluent limits in the same way as the steady-
state methods.
4.1 DILUTION MODEL
The continuous simulation model is a 21 MB excel workbook file titled "Yakima Dynamic
Model.xls," with multiple linked spreadsheets. The following tables describe the method of
calculating dilution factors on a daily basis, as presented in the spreadsheets, which are included
on the Mixing Zone Study CD.
Yakima Dynamic Model.xls — "Dynamic Model" Worksheet
Column
Description
A
Date
B
Julian day
C
River discharge (cfs) from "River Q" worksheet
D
Effluent flow (cfs) from "WWTP Effluent" worksheet - from DMR data
E
Acute RIVPLUM model result from column BC in "Rivplum" worksheet
F
Acute dilution based on 2.5 percent of ambient flow
G
Minimum of Columns E and F
City of Yakima
IVIVTP Effluent Mixing Zone Study
4-1
B&V007
September 2003
Yakima Dynamic Model.xls — "Dynamic Model" Worksheet
Colunm
Description
H
I
J
K
Chronic RIVPLUM model result from column DG in "Rivplum" worksheet
Chronic dilution based on 25 percent of ambient flow
Minimum of Columns H and I
Running 4 -day average of Column J
Annual Regression Statistics. Rows 3 through 3409 include daily data and model results
between 1994 and 2003. In Rows 3411 through 3426 are the statistics used to calculate the
critical dilution factors based on the continuous simulation model. Rows 3413 through 3421 list
the minimum dilution factors for each water year as shown. Acute values are in Column G and
4 -day chronic values are in Column K. Logio transformed values of the annual minima are in
Columns H and L. Mean, standard deviation and Z -statistics are provided in Rows 3423 through
3425. The resulting dilution factors with a 3 -year recurrence probability are presented in Row
3426. The ACEC and CCEC corresponding to these dilution factors are presented in Cells I3426
and M3426, respectively.
Seasonal Regression Statistics. Seasonal dilution factors based on the continuous simulation are
presented in Rows 3428 to 3460. EPA (1984) suggests adjusting the return period to
approximate the same risk in seasonal permit programs as in non -seasonal (or annual) permit
limits. This is the same rationale for using the 7Q20 for seasonal permits as required in the
Permit Writer' Manual.
The return period (Y) for seasonal permit periods which corresponds to the allowed annual
probability (e.g. P = 1/3 for an annual three-year return period) is related to the number of
permitting periods (N) within the year by the following equation (EPA, 1984):
1'=(1—(1—P)f"}"1
For P = 0.333 and N = 2, a seasonal return period (Y) of 5.4 years will satisfy this criteria.
Therefore, semi-annual permit periods require that the criteria are not exceeded more than once
every 5.4 years in each season to maintain an annual risk of exceeding criteria of no more than
once every 3 years. The Z -statistic for a 5.4 -year recurrence interval (0.18 probability) is 0.90,
which is used in Rows 3442 and 3459 of the spreadsheet.
City of Yakima B&1'007
IMP Effluent Mixing Zone Study 4-2 September 2003
4.2 CONTINUOUS SIMULATION FOR AMMONIA
Ammonia is a complex parameter. The criteria vary depending on species present, and are for
the un -ionized form of ammonia. Therefore, the water quality criteria for total ammonia (as N)
are dependent on pH and temperature. The temperature and pH in the mixing zone are a function
of the dilution at the mixing zone boundaries. The mixed temperature may be calculated by a
simple mixing analysis due to the short duration in the mixing zone (less than 2 minutes to the
chronic mixing zone boundary). However, the mixed pH is a function of the buffering
capabilities (i. e. alkalinity) of both the effluent and receiving water. The description of the
dynamic model spreadsheet continues below:
Yakima Dynamic Model.xls — "Dynamic Model" Worksheet (continued)
Column
Description
L
pH at the acute mixing zone boundary, from "phmix" worksheet (see below)
M
pH at the chronic mixing zone boundary, from "phmix" worksheet (see below)
N
Temperature at the acute mixing zone boundary, from "plmnix" worksheet
0
Acute ammonia -N criterion, from "NH3-N Criteria" worksheet
P
Chronic anunonia-N criterion, from "N1 -13-N Criteria" worksheet
Q
Effluent ammonia from "WWTP Effluent" worksheet, interpolated for daily values from DMRs
R
Ambient ammonia from "Amb Qual Data" worksheet, values used are monthly maxima from the
period of record (1994-2003) at Ecology Stations 37A210 and 37A205 (upstream of the Yakima
WWTP), see Figure 2
S
Anunonia-N concentration at the acute mixing zone boundary, a function of ambient concentration,
effluent concentration and acute dilution
T
Ammonia -N concentration at the chronic nixing zone boundary, a function of ambient
concentration, effluent concentration and acute dilution
U
A logical function comparing the acute mixing zone concentration to the acute criterion, note all
responses are "YES" for compliance
V
A logical function comparing the chronic mixing zone concentration to the chronic criterion, note
all responses are "YES" for compliance
W
Acute wasteload allocation is the effluent ammonia concentration that would exactly meet the acute
water quality criterion at the nixing zone boundary
X
Chronic wasteload allocation is the effluent ammonia concentration that would exactly meet the
chronic water quality criterion at the mixing zone boundary
Y
This is the running 4 -day average for the chronic wasteload allocations
RLI. Conservative assumptions were used in the determination of pH at the acute and chronic
mixing zones, which control the water quality criteria for ammonia. Ambient and effluent data
are taken infrequently for pH, temperature, and alkalinity, so the following conservative
assumptions were used as described in the tables below:
City of Yakima
ff'ff'7P Effluent Mixing Zone Study 4-3 September 2003
B&V007
Yakima Dynamic Model.xls — "phmix" worksheet
Column
Description
A
Date
B
Daily ambient pH is taken as the maximum monthly values for each month from the Ecology data
from 1994-2003, which are shown in Figure 3. Note that maximum pH values of approximately 9
standard units were observed in the months of May, July and October. In the dynamic model, all
sununer months including June, August and September were also assigned ambient pH values of
9.0.
C
Daily ambient temperature is taken as the maximum monthly values for each month from the
Ecology data from 1994-2003, which are shown in Figure 4.
D
Ambient alkalinity is taken as the 10th percentile value from Ecology, the same as used in the
NPDES permit
E
Effluent pH is the same as used in the NPDES permit (90th percentile)
F
Effluent temperature varies from 15°C on February 1 to 25°C on August 1
G
Effluent alkalinity is the 10th percentile value of 45 mg/L CaCO3 (note Ecology used the 90th
percentile value of 117 mg/L for the NPDES permit).
0.2
0.18
0.16
0.14
0.12
m 0.1
0.08
0.06
0.04
0.02
Ambient Ammonia (NH3•N)
•
•
•
s i i
•
• • •
• • •
•
Jan Feb Mar Arp May June July Aug Sept Oct Nov Dec
Figure 2 Ambient Ammonia -N Data
City of Yakima
II'IPTP Effluent Mixing Zone Study 4-4
B&Y007
September 2003
9.5
9
8,5
• 8
a
7.5
7
•
Ambient pH
4-
•
• 4
• -•
• •
•• • • • • •
•• • •
•
•
• ---4- • •
• • • • i
• • • •
♦ • • 4
•
•
•
-4-
8.5 +-
U
25
20
15
10
5
•
•
•
Jan Feb Mar Apr May June July Aug Sep Od Nov Dec
Figure 3 Ambient pH Data
S
•
••
Ambient Temperature
•
s
•
•
•
1
•
•
• —�
•
••
1 •
•
•
i
•
•
1
•
•
•
•
•
2 •
_ •
1
•
•
•
•
0 •—
Jan Feb Mar Apr May June July Aug Sep Oce Nov Dec
Figure 4 Ambient Temperature Data
City of Yakima
WIVTP Effluent Alirrng Zone Study
4-5
B&V007
September 2003
Critical Ammonia Wasteload Allocations. The critical wasteload allocations for ammonia -N are
calculated for the annual and seasonal return period exactly the same way as for dilution, per
EPA protocol (1991). In rows 3411 through 3426, column W through Z, the critical acute and
chronic wasteload allocations are calculated for an annual 3 -year return interval. In rows 3428
through 3460, the critical wasteload allocations are calculated for 5.4 -year return intervals for the
March — September and October — February seasons. The critical allocations are based on log -
transformed values as recommended by EPA (1991).
4.3 CONTINUOUS SIMULATION FOR METALS
Compliance with metals criteria is also complex. The criteria vary as a function of water
hardness. Additionally, the criteria are for dissolved fraction of the metal, but effluent limits
must be expressed as total recoverable. The mixed hardness may be calculated by a simple
mixing analysis. The metals translators (fraction of dissolved to total recoverable) are taken
from the work by CH2M Hill dated June 2000, which are the same values Ecology used in the
NPDES permit and Fact Sheet. The spreadsheet discussion continues below:
Yakima Dynamic Model.xls — "Dynamic Model" Worksheet (continued)
Column
Description
AA
The City of Yakima have tested regularly for effluent hardness since April 1997. The daily values
presented in this column are based on the nearest data points temporally over this period. Data are
presented in Figure 5.
AB
The City of Yakima have tested regularly for river hardness since April 1997. The daily values
presented in this column are based on the nearest data points temporally over this period. Data are
presented in Figure 5.
AC
Hardness at the acute mixing zone boundary is based on simple dilution calculation
AD
Hardness at the chronic mixing zone boundary is based on simple dilution calculation
AE
Acute copper criteria (dissolved) are calculated on a daily basis as a function of hardness at the
acute nixing zone boundary
AF
Chronic copper criteria (dissolved) are calculated on a daily basis as a function of hardness at the
chronic mixing zone boundary
AG
Critical ambient copper concentration is the 90th percentile (dissolved) from the June 2000 CH2M
Hill study, the same values used in the NPDES permit
AH
Acute wasteload allocation is the effluent copper concentration that would exactly meet the acute
water quality criterion at the mixing zone boundary
AI
Chronic wasteload allocation is the effluent copper concentration that would exactly meet the
chronic water quality criterion at the mixing zone boundary
AJ
The running 4 -day average for the chronic wasteload allocations
AK — AP
These columns are identical to AE through AJ, but for lead
AQ — AS
Identical to AE through AJ, but for silver (acute only, no chronic criterion)
AT - AY
These columns are identical to AE through AJ, but for zinc
City of Yakima
li'WTP Effluent Mixing Zone Study
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September 2003
90
80
70
U
U
;U
50
rn
E
N
40
z - -
0
10
River and Effluent Hardness
0
1/2/97
112198 1/2109 1/2100 111101 1/1/02 1/1/03 111/04
Date
—Effluent
River
Figure 5 Effluent and Ambient Hardness
Data
Critical Metals Wasteload Allocations. The critical wasteload allocations for metals are
calculated for the annual and seasonal return period exactly the same way as for dilution and
ammonia, per EPA protocol (1991). In rows 3411 tluough 3426, the critical acute and chronic
wasteload allocations are calculated for an annual 3 -year return interval. In rows 3428 through
3460, the critical wasteload allocations are calculated for 5.4 -year return intervals for the March
— September and October — February seasons. The critical allocations are based on log -
transformed values as recommended by EPA (1991).
City of Yakima B&V007
IVIV7P Effluent Mixing Zone Study 4-7 September 2003
SECTION 5:
EFFLUENT LIMITS
5.1 METHODOLOGY AND RESULTS
Effluent limits are calculated for ammonia, copper, lead, silver and zinc using Ecology and EPA
protocols. The results of each mixing zone analysis method are shown in Table 6.
The spreadsheets supporting Table 6 are provided in Appendix A and in Excel files on the
Mixing Zone CD titled "Ammonia Limits.xls" and "Metals Limits.xls," which are both linked to
"Yakima Dynamic Model.xls." The metals translators are those presented in the June 2000 study
by CH2M Hill, which Ecology used in the NPDES permit. The following text describes each
method of permit limit calculation in Appendix A:
• The first line in each parameter table recreates the annual effluent limits calculated by
Ecology for the current NPDES permit. The lone exception is for lead, which may have
been incorrect in the permit. Except for lead, this analysis confirms the limits calculated
by Ecology using the standard (or default) steady-state methods including the historical
7Q10 river discharge of 632 cfs.
• The second line in each table is based on standard steady-state methods, but with the
revised 7Q10 river discharge of 908 cfs as described previously.
• The third and fourth lines in each table are for seasonal permit limits for March —
September and October — February using the revised 7Q20 river discharge statistics.
• The fifth line in each table calculates annual permit limits using the revised 7Q10 river
discharge and the default steady-state methods. However, this method assumes that the
City of Yakima would qualify for a variance of the mixing zone criteria based on 2.5
percent (acute) and 25 percent (chronic) of ambient flow, based on the discharge existing
prior to November 1992 and meeting the other variance criteria in the WAC. Therefore,
the dilution factors used for this line of effluent limits are based on the RIVPLUM model
results that were presented in Table 5.
City of Yakima B&V007
Wli'TP Effluent Mixing Zone Study 5-1 September 2003
Table 6 Summary of Alternative Dilution Factors and Corresponding Effluent Limitations
Acute
Dilution
Factor
ACEC
Chronic
Dilution
Factor
CCEC
Ammonia as N
Copper
Lead
Silver
Zinc
Average
Monthly
Limit
(mg!L)
Max.
Daily
Limit
(mg/L)
Average
Monthly
Limit
(u;IL)
Max.
Daily
Limit
(u;IL)
Average
Monthly
Limit
(µg/L)
Max.
Daily
Limit
(gip
Average
Monthly
limit
(µg/L)
Max.
Daily
Limit
(µgJL)
Average
Monthly
Limit
(µg/L)
Max.
Daily
Limit
(µg[L)
Ecology's Steady State
Condition
1.51
0.66
6.61
0.15
5.3
I7.8
6.72
9.80
5.19
7.57
2.18
3.18
45.71
66.68
Steady State Condition
Iv/ New 7Q10
1.74
0.57
9.07
0.11
7.1
23.9
7.23
10.55
6.75
9.85
2.26
3.30
49.98
72.91
Seasonal Steady State
Condition
October - February
March - September
1.73
2.55
0.58
039
8.99
18.0
0.11
0.06
7.1
9.3
24.1
31.3
7.21
9.05
1052
1320
6.70
12.43
9.77
18.13
2.26
2.60
3.30
3.79
49.80
64.90
72.64
94.68
Steady Statewl
Variance of WAC 173-
201A-400
4.16
024
132
0.08
83
28.0
12.64
18.43
9.38
13.68
3.35
4.89
9434
137.63
Dynamic Condition -
Annual
WLA
calculated
0.45
WLA
calculated
0.07
7.7
28.0
10.71
15.62
13.66
19.93
3.42
5.00
73.61
10739
Dynamic Condition -
Seasonal
October -February
March - September
alcuullated
cuuiated
r culated
c WLA �
83
13
282
252
1025
11.43
14.95
16.67
1322
1537
1928
22.43
3.49
3.01
5.09
439
69.56
91.95
101.48
11955
• The sixth line in each table calculates effluent limits from the continuous simulation
dynamic modeling for annual basis. The metals translators and ambient values are the
same critical values Ecology used in the current NPDES permit. However, the critical
wasteload allocations are not constant steady-state values, but rather are daily varying
values determined from the continuous simulation results. The acute and chronic
wasteload allocations in the ammonia and metals limit spreadsheets are linked to the
values calculated in "Yakima Dynamic Model.xls" as described above.
• The seventh and eight lines in each table are for seasonal permit limits for March -
September and October -February using the continuous simulation modeling wasteload
allocations.
5.2 RECOMMENDED WATER QUALITY -BASED EFFLUENT LIMITS FOR THE
CURRENT NPDES PERMIT
The recommended effluent limits for the current NPDES permit are those based on the
continuous simulation dynamic modeling. This wasteload allocation method is fully supported
by Ecology and EPA protocol, and provides a more accurate determination of limits designed to
meet water quality criteria in the receiving water.
The ACEC and CCEC should be based on annual dilution factors calculated from the continuous
simulation model. Likewise, metals concentrations do not exhibit seasonal trends, thus the
recommended limits are based on the annual model. However, ammonia concentrations are
seasonal, as is the treatment plant's ability to remove ammonia. Therefore, the ammonia limits
should vary seasonally based on the continuous simulation model results. Recommended
effluent limitations for the current NPDES permit are provided in Table 7.
Table 7 Recommended Effluent Limits for the Current NPDES Permit
Parameter
Average Monthly Limit
Maximum Daily Limit
Ammonia as N
October — Febniary
March - September
8.3 mg/L
7.5 mg/L
28 mg/L
25 mg/L
Copper
10.7 µg/L
15.6 µg/L
Lead
13.7 µg/L
19.9 lig/L
Silver
3.4 µg/L
5.0 µg/L
Zinc
73 µg/L
107 µg/L
ACEC = 45%, CCEC = 7.2%
City of Yakima
{WIT Effluent Mixing Zone Study
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September 2003
5.3 PROJECTED WATER QUALITY -BASED EFFLUENT LIMITATIONS AT
BUILDOUT
There are a lot of variable factors that will determine water quality -based effluent limitations for
ammonia and metals in the future, including the growth in effluent flow rates, potential changes
in low -flow management of the watershed by BOR, and long-term changes in ambient water
quality in the Yakima River system upstream of the WWTP. In the absence of any knowledge
regarding future changes in ambient conditions or BOR control strategies, effluent limit
projections for buildout conditions are based on future effluent flow projections.
Effluent flow projections were developed by HDR in the October 2000 Draft Wastewater
Facilities Plan. That report established a baseline annual average flow of 11.28 mgd for 1999.
The annual average flow at buildout was projected to be 22.37 mgd, which is approximately
double the 1999 projection. Since the recommended effluent limits for the current NPDES
permit are based in -part on 1999 effluent flows, this ratio of future -to -current flows will be used
to project effluent limits for ammonia and metals at buildout.
The dynamic model used for buildout flows is titled "Buildout Dynamic Model.xls" and is
included on the companion CD. Effluent flows are doubled in that version of the continuous
simulation model, and all other parameters are unchanged. The projected buildout ammonia and
metals limits are calculated in "Buildout Ammonia Limits.xls" and "Buildout Metals Limits.xls."
The projected buildout effluent limits are presented in Table 8.
Table 8 Projected Buildout Effluent Limits
Parameter
Average Monthly Limit
Maximum Daily Limit
Ammonia as N
5.8 mg/L
20 mg/L
Copper
8.0 µg/L
11.6 µg/L
Lead
7.6 µg/L
11.1 µg/L
Silver
2.6 tg/L
3.7 µg/L
Zinc
55 µg/L
80 pg/L
ACEC = 62%, CCEC = 13.4%
City of Yakima
iVWVTP Effluent Mixing Zone Study 5-4
B& V007
September 2003
SECTION 6:
FUTURE BASIN -WIDE WATER QUALITY ISSUES
There are various water quality concerns in the Yakima River associated with cumulative point
and nonpoint discharges in the watershed. As these basin -wide water quality concerns are
identified, Ecology is charged with allocating equitable wasteload limits for all sources to bring
the river into compliance with the standards. The field investigations and modeling studies for
many of the water quality paratneters of concern are not completed at this time, thus we are
unable to project the potential effluent limits for the treatment plant that may result from the
basin -wide water quality controls.
In this section of the report we describe the current water quality parameters of concern for the
Yakima basin, and establish facility planning guidelines so that future wastewater facility
improvements would be capable of adapting to additional effluent limits. The principal effluent
constituents that fall into this category of potentially greater restrictions are CBOD5 and
phosphorus.
6.1 303(d) LISTINGS
Section 303(d) of the federal Clean Water Act requires states to create a list of surface waters
that are not meeting water quality standards. The current 303(d) list was adopted in 1998. The
Yakima WWTP discharges to Segment ID No. WA -37-1040 of the Yakima River, which
extends from the Sunnyside Dam Bridge at mile 103.8 to the Naches River at mile 116.3. The
lower portion of this segment is under the jurisdiction of the Yakama Indian Nation.
Yakima River segment No. WA -37-1040 was placed on the 1998 303(d) list for ammonia,
chlorine, fecal coliform, mercury, and silver. The ammonia and chlorine listings are attached to
the Zillah WWTP discharge, and do not affect the Yakima WWTP. The mercury and silver
listings are based on data obtained by USGS using discredited techniques. A recent Ecology
study (Johnson 2000) revealed analytical errors in the USGS data, and all new samples analyzed
by Ecology were well within state standards for aquatic toxicity. The study further recotntnends
that these parameters be removed from the 303(d) list in the next update.
City of Yakima B&VV007
►VWTP Effluent Mixing Zone Study 6-1 September 2003
The lower Yakima River was included on the 1996 303(d) list for sediment and sediment -borne
pollutants like DDE and DDT attributed to irrigation returns. A suspended sediment and DDT
total maximum daily load (TMDL) study was completed by Ecology (Joy and Patterson 1997),
as required under the Clean Water Act. The TMDL established sediment reduction goals and
irrigation return policies that are expected to produce compliance with the DDT human health
criteria in fish and water by 2017. None of the requirements in the TMDL include limitations
relevant to the City of Yakima WWTP.
6.2 TEMPERATURE
Both the previous and recently updated state water quality standards include a special condition
for temperature in the Yakima River, consisting of a revision of the standard to 21°C. The
Yakima River reach near Yakima is not included on the 303(d) list for temperature. Since the
criteria did not change, no listing is imminent. However, downstream reaches of the Yakima
River and several upstream tributaries (e.g., Naches River) are listed. A TMDL for temperature
will be initiated by Ecology in 2004, and may incorporate the Yakima WWTP discharge
The impact of the Yakima WWTP discharge on the receiving water was modeled by a simple
mass balance mixing analysis using the revised chronic dilution factor of 13.8. An effluent
temperature of 24°C and ambient temperature of 19.9°C have been assumed for the calculation
of temperature impacts. The temperature water quality standard will be met, as shown in
Table 9. The maximum temperature at the mixing zone boundary will be 20.2°C at 90th
percentile ambient conditions, which is under the 21°C criteria. The maximum temperature
increase above ambient will be 0.3°C, which is less than the maximum increase of 1.5°C allowed
in the water quality standards.
Table 9 Analysis of Temperature Impact.
Effluent Temperature (°C)
24.0
Ambient Temperature (°C)
19.9
Dilution Factor
13.8
Final Temperature (°C)
20.2
Water Quality Standard (°C)
21.0 (max)
Temperature Increase (°C)
0.3
Water Quality Standard (°C)
1.5 (max increase)
City of Yakima
JVWTP Effluent Miring Zone Study
6-2
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September 2003
Ecology also evaluated the temperature impact of the Yakima WWTP discharge in the NPDES
permit fact sheet, and also concluded that the temperature criteria will be met. Therefore, no
temperature limitations are anticipated to be required now or in the foreseeable future. However,
wastewater facility improvements should be designed to not significantly increase the
temperature of the effluent over existing conditions, in order to ensure future compliance.
6.3 BIOCHEMICAL OXYGEN DEMAND
The standard for dissolved oxygen is met in river segment WA -37-1040, thus is not included on
the 303(d) list. However, river segments downstream from the Yakima WWTP (WA -37-1010)
are on the 303(d) list for oxygen. Therefore, Ecology is obligated to perform a TMDL for the
lower Yakima River to achieve compliance with the dissolved oxygen standard. The TMDL
may include allocations for CBOD, anunonia and phosphorus. Because of the delayed -effect
nature of dissolved oxygen dynamics, the TMDL will likely need to extend to upstream
segments in order to meet downstream criteria. Ecology has stated their intent to develop a
comprehensive dissolved oxygen and nutrient model for the lower Yakima River that would
extend at least to the confluence of the Yakima and Naches Rivers, thus would include the
Yakima WWTP discharge (Joy, 2000).
The impact of the City's discharge on dissolved oxygen was modeled by Ecology with a very
conservative model named DOSAG, which is a simple spreadsheet version of the modified
Streeter -Phelps equation. The results of the model are presented in the Fact Sheet for the
NPDES permit, and suggest that there is a'potential for the Yakima WWTP discharge to exceed
the dissolved oxygen criteria downstream. Ecology uses the DOSAG model as a screening tool
to assess whether additional analysis is necessary. Ecology has concluded that additional
analysis is necessary for the Yakima WWTP since (1) there are multiple sources of oxygen
demanding wastes in the Yakima watershed, (2) the effects of dams and other hydraulic
structures on dissolved oxygen are beyond DOSAG's capabilities, and (3) a TMDL is required
for dissolved oxygen in the lower Yakima River.
Ecology will conduct a TMDL for dissolved oxygen in the Yakima River that will consider
cumulative loadings of BOD and nutrients (Joy, 2002). As stated in the current NPDES permit,
allowable CBOD loadings for all sources will be determined after a comprehensive TMDL
City of Yakima B&V007
IVIVTP Effluent axing Zone Study 6-3 September 2003
model is developed. Therefore, it is not feasible to predict future CBOD limits for the Yakima
WWTP until the TMDL is completed, which is likely to be approximately five years.
Interim effluent limits will be the same technology-based limits in the current permit. Final
CBOD limits will be established through a revision to the NPDES permit when the TMDL is
completed. Therefore, wastewater facility modifications occurring in this interim period should
be planned with allowances for future upgrades that would reduce CBOD loadings below the
current technology-based limits, if that should result from a future TMDL.
6.4 PHOSPHORUS
Discharges of nitrogen and phosphorus may stimulate algal growth in the form of periphyton
attached to the river substrate, or suspended algae in reservoirs. Excessive periphyton or
phytoplankton growth may adversely impact pH, dissolved oxygen, fisheries habitat and visual
aesthetics. Ecology has determined that nitrogen is readily available in Washington rivers and
streams. Therefore, control of nuisance algal growth is typically accomplished by limiting
phosphorus discharges from anthropogenic sources, including wastewater treatment plants. For
example, phosphorus controls have been placed on dischargers in the Spokane River for many
years to control periphyton, pH, and dissolved oxygen.
The Yakima River is not currently included on the 303(d) list for phosphorus or any other
parameters related to excessive periphyton growth. There are no phosphorus limitations on any
point or nonpoint discharges to the river, and no known phosphorus management plans have
been developed in the watershed. Therefore, the current NPDES permit does not include
phosphorus limitations.
However, Ecology has identified phosphorus as a parameter of concern and will include it in the
anticipated dissolved oxygen TMDL for the Yakima River (Joy, 2002). Additionally, EPA is
developing nationwide nutrient criteria for rivers, and Ecology is planning for eventual adoption
of such criteria in Washington. Point and nonpoint discharge criteria for phosphorus are
anticipated in the future. Wastewater discharges to streams may be required to remove
phosphorus through treatment. Wastewater facility modifications occurring in this interim
period should be planned with allowances for future upgrades that would reduce phosphorus
loadings.
City of Yakima B&V007
IVIVTP Effluent Afirxing Zone Study 6-4 September 2003
SECTION 7:
REFERENCES
BOR. 2001. Yakima Field Office Project Operations Outlook, 2001 Irrigation Season.
Prepared by the Yakima Field Office, U.S. Bureau of Reclamation, last revised May 2,
2001.
Ecology. 1992. Permit Writer's Manual. Washington State Department of Ecology Publication
No. 92-109. Olympia, WA.
Ecology. 1998. Criteria for Sewage Works Design (Orange Book). Washington State
Department of Ecology. Olympia, WA.
EPA. 1991. Technical Support Document for Water Quality -based Toxics Control. EPA 505/2-
90-001. U.S. Environmental Protection Agency. Office of Water. Washington, D.C.
EPA. 1986. Quality Criteria for Water (Gold Book). U.S. Environmental Protection Agency.
Washington, D.C.
Fischer, H.B. 1979. Mixing in Inland and Coastal Waters. Academic Press, New York.
Johnson, A. 2000. Concentrations of 303(d) Listed Metals in the Upper Yakima River. Ecology
Publication No. 00-03-024, Olympia, WA.
Joy, J. and B. Patterson. 1997. A Suspended Sediment and DDT Total Maximum Daily Load
Evaluation Report for the Yakima River. Ecology Publication No. 97-321, Olympia, WA
Joy, J. 2002. Personal communication via email between Joe Joy (Ecology) and Bill Fox
(Cosmopolitan Engineering Group) dated November 22, 2002.
City of Yakima B&V007
WIVTP Effluent Mixing Zone Study 7-1 September 2003