HomeMy WebLinkAboutR-2002-021 Wastewater Facilities Plan - Draft October 2000 - PART 1City of Yakima
Wastewater Eaciljties Plan
DRAFT
October 2000
prepared by
HDR Engineering, Inc.
Prepared for
City of Yakima, Washington
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Transmittal Memorandum
for Wastewater Study Session
Police Station/Legal Center
2nd. Floor Training Room
November 7, 2000
7:30 AM
To: Honorable Mayor and Members of the City Council,
Dick Zais, City Manager
From: Glenn Rice/Assistant City Manager
Doug Mayo/Wastewater Manager
Re: MANDATED Draft 2000 Wastewater Facilities Plan
City staff and HDR Engineering, Inc. are please to present for your
review and comment the Mandated Draft 2000 Wastewater Facilities
Plan. This document looks to the capital and operations and
maintenance requirements (including staffing) of the wastewater
system to serve the area for the next 20 years. Submittal of a
Council adopted Plan to Ecology is mandated under WAC 173-240.
Approval by Ecology is required to allow the City to be eligible to
compete for any Federal or State funding options. The guidelines for
the Plan are also found in WAC 173-240.
This document was also distributed to the City of Union Gap, Terrace
Heights Sewer District, Yakima County, and Ecology for their review
and comment. Copies are also available for public review. A Public
Hearing will be scheduled early next year to discuss comments and
concerns.
Indicated in this document are extensive investment needs over the
next 6 - 20 years for Mandates, Renewal/Reliability, and Growth.
The needs during the next 6 years alone are for the treatment
facility ($12,200,000 -100% mandated) as well as the collection
system ($7,500,000 -50% mandated). Over 80% or $15.9 million of
the total 6 year program is mandatory.
Compliance with federal and/or state mandatory regulations
requires adequate funding sources regardless of ability to pay.
Although the federal and/or state regulatory agencies sometimes
provide partial funding for mandated improvements in the form of
grants and/or loans, those resources have been drastically
diminished over the last decade. As a consequence, the City of
Yakima and the Yakima Regional WWTP will be required to use
wholesale and retail revenues to pay a substantial portion (as much
as 90% or more) of the total cost either as cash or through debt
payments. The impact to wholesale and retail rates will be
significant.
The Cost of Service Update and Update to the Wastewater Connection
Charge that accompany the Facilities Plan will follow next April.
The Cost of Service will present strategies to finance the
mandatory improvements over the next 6 years.
Plant improvements needed to accommodate food processing waste
(Del Monte) have not been factored into this document. A separate
report discussing the implications of this activity will follow. Any
City costs allocated to this activity will also be identified and
incorporated in the Cost of Service Report.
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DRAFT
• City of Yakima
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Executive Summary of Mandatory
Draft 2000 Wastewater Facilities Plan
MANDATORY RESPONSIBILITIES
Over the past 50 to 60 years, the laws, rules, regulations, and requirements of both the federal
and state government, relating to public health, have increased significantly. The Code of
Federal Regulations (CFR) for the United States currently contains 50 Titles that in some way
effect daily lives of all citizens. Title 40 of the CFR is entitled "Protection of Environment" and
sets forth the laws, rules, regulations, and requirements of the Environmental Protection Agency.
Compliance with the requirements of the Code of Federal Regulations is mandatory by all state
and local jurisdictions, including their legislative bodies and all citizens of the United States.
In accordance with the rights reserved to states under the Tenth Amendment of the Constitution,
and not to be outdone by the adoption of laws, rules, regulations, and requirements of the federal
government, the State of Washington has also established their own legislation which effects the
daily lives of the citizens of the state. The Revised Code of Washington (RCW) identifies the
laws of the State.
Once a law (RCW) has been adopted by the state legislature, the rules, regulations, and
requirements for implementation of the RCW are developed by the specific agency considered to
jurisdiction. These rules, regulations, and requirements are identified as Washington
Administrative Code (WAC). The WDOE has developed and/or participated in the development
of 161 WACs. On an annual basis, many of the WACs are revised, modified, changed,
corrected, or added to; to reflect changes in federal and/or state regulations; to reflect the opinion
of WDOE; to respond to either known or perceived concerns with existing WACs; or to reflect
the opinion of specific interest groups. Of the 161 WACs currently indexed by WDOE, 42 are
currently under review for revision, modification, change, correction, or addition.
Both the Washington State Legislature and WDOE have elected to develop, adopt, and
implement RCWs and WACs which are often times more onerous and restrictive than those
adopted by the Federal Legislature and EPA. The primary law (RCW) which effects wastewater
treatment plant discharge of treated effluent to the environment is RCW 90.48. This RCW is
also considered by WDOE to be primary law for the control of stormwater discharge.
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HDR ENGINEERING, INC.
CITY OF YAKIMA
OCTOBER 25, 2000
PACE I
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DRAFT
In the development of this Mandatory Wastewater Facilities Plan, the capital facilities and the
requirements for annual operations and maintenance have been identified as either Mandatory or
Non -mandatory.
Mandatory capital facility improvements are those projects which add to the existing wastewater
facilities and are required to meet existing and new laws, rules, regulations, and requirements of
the federal and/or state government. There are currently no constraints on the federal and/or state
legislators, or the implementing agencies such as EPA and WDOE, for the adoption of new laws,
rules, regulations, and requirements. Renewal, replacement, and health and safety capital
improvements are mandatory in maintaining cost-effective wastewater facility needs, and in
complying with the existing laws, rules, regulations, and requirements of the federal and/or state
government. It is not anticipated that the mandatory existing laws, rules, regulations, and
requirements will be relaxed in the future.
In addition to this mandatory requirement to comply with existing and new laws, rules,
regulations, and requirements of federal and state government, the City of Yakima was delegated
with the responsibility to provide for regional wastewater collection and treatment of sewage
within the Yakima Metropolitan area by WDOE in the mid 1970s. 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. The Four Party Agreement created a mandatory
obligation for the City of Yakima to offer regional treatment plant and interceptor capacity to
handle the sewage flows from and within an Urban Service Boundary. The Urban Service
Boundary was revised in 1982 to correspond with the Yakima Urban Area Comprehensive Plan
boundary as adopted by the City of Yakima, Yakima County, and the City of Union Gap.
Mandatory compliance with federal and state laws, rules, regulations, and requirements extends
to the ongoing obligations of adequately staffing, operating, and maintaining the facilities once
they are constructed. Over the course of the past 50 to 60 years, just like new requirements for
higher levels of treatment, new requirements for staffing, operation, and maintenance have been
adopted by the federal and state regulating agencies. Municipal agencies, like the City of
Yakima, have been required to comply, regardless of ability to pay. Non compliance can be
considered as a criminal act subject to significant fines and incarceration upon conviction.
Non -mandatory capital facility improvements are those projects which are considered
discretionary. Such projects for the City of Yakima include expansion of the interceptor sewers
and the wastewater treatment plant to accommodate other Growth related expansion occurring
outside the boundaries as defined in the "Four Party Agreement". Non -mandatory obligations of
staffing, operation and maintenance would be associated with the operations and maintenance of
non -mandatory capital facilities.
FUTURE IMPROVEMENT ACTIONS
Improvements/expansions to the wastewater facilities for the Yakima Regional WWTP and for
the City of Yakima Wastewater Collection System have been separated into the period into
which the improvements would be made (0-6 years; 7-12 years; and 13-20 years), and further
HDR ENGINEERING, INC.
CITY OF YAKIMA
OCTOBER 25, 2000 PAGE 2
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DRAFT
separated into two categories (Mandated by federal/state agencies to meet current and future
regulation; mandated to meet current and future health and safety regulations; mandated to meet
Growth related expansion of the service area by the Four Party Agreement; and other Growth
related expansion) for the Yakima Regional WWTP, and two categories (Mandated to meet
Growth related expansion of the service area by the Four Party Agreement; and other Growth
related expansion) for the collection/interceptor sewer system. Other Growth related expansion
is identified as those costs attributed to population growth into the Yakima Urban Reserve area.
Table 1 summarizes the total opinion of probable cost for wastewater treatment plant and
collection system costs over the next 20 years by the time period for which they are anticipated to
occur.
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HDR ENGINEERING, INC.
CITY OF YAKIMA
OCTOBER 25, 2000 PAGE 3
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DFT
TABLE 1. SUMMARY OF IMPROVEMENTS
TREATMENT/
COLLECTION
OPINION OF
PROBABLEREGULATIONS
COST
MANDATORYI`'
=
T `: _ _ ., :-.::.`
TORY '
M~Je ry
a
GROWTHg
>
;:.
:TOTEI.I';%`_:_;;:
''"`GROWTH £
`F� 4 £'
REGULATIONS
RE NEWAL/SAFETY1VIANUA
Wastewater Treatment
0-6 Year Projects3
7-12 12 Year Projects
13-20 Year Proj ects
$12,197,900
$25,880,400
$8,765,600
$10,105,600
$16,840,300
$2,079,300
$2,092,300
$4,673,500
$2,138,500
... .:
:' . M
"'':83.1;;,
48:
----
$4,366,600
$4,547,800�.�.".
� �., • ,:.._"'"
16.9
:9` .
,
Total Treatment
Plant Improvements
$46,843,900
$29,025,200
$8,904,300
; "' '' ' "'83.0;=: _1
$8,914,400
1'9 0 '
Collection Facility
0-6 Year Projects3
7-12 Year Projects
13-20 Year projects
$7,529,400
$21,710,400
$10,844,700
$1,866,700
$8,141,900
$3,253,400
$1,867,000
----
----
;�.�., .
9.
<'�r: " ::;49.6.x 8=
.s`'.
0
$3,795,700
$13,568,500
$7,591,300
a,,.- � �� 50
22'1
M"'
olle
Total Collection
Facility
Improvements
$40,084,500
$13,262,000
$1 ,867,000
`t
�37`7 " .
� -: ,
�`5'-vary �.�'�.c•t .�,t,:"
$24 955 500
¢ �'�=r
..':.
;:
.:�, 4 �x
,.•.
TOTAL
TREATMENT/
COLLECTION
iT A.._"J ...__.. 1:
$86,928,400
. r
$42,287,200=_
$10,771,300
;� _61�0�=�::� .:
c*�., ��� ggam�.. ..}
$33,869,900
=
; -�->
raiistate laws and regulations, an
projects.
2Non-mandatory growth/system expansion.
3For the 0-6 Year period, a total of $19,727,300 is required. $15,93
meet non -mandatory growth/system expansion.
the Four Party Agreement. Non -mandatory growth/system expansion receives a benef t from mandatory
1,600, or 80.8 percent, is required to meet mandatory obligations. $3,795,700, or 19.2 percent, is required to
HDR ENGINEERING, INC.
CITY OF YAKIMA
OCTOBER 2.5, 2000
PAGE 4
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DRAFT
During the next 6 years, the Yakima Regional WWTP must invest $12,197,900 in the treatment
facilities, 100 percent of which is required to meet mandatory regulatory requirements, to
maintain existing facilities, and to provide for mandatory system expansion within the Service
Area. Also during the next 6 years, the City of Yakima and the development community must
invest $7,529,400, 49.6 percent of which is required to meet mandatory requirements, in
extension of new interceptor and trunk sewers into currently unsewered areas, and in replacement
and/or parallel interceptor and trunk sewers to accommodate the expanded Service Area.
Over the 20 -year period, the Yakima Regional WWTP must invest $46,843,900 in the treatment
facilities to meet mandatory regulatory requirements, to maintain existing facilities, and to
provide mandatory and non -mandatory system expansion for growth within the Service Area.
During this same period, the City of Yakima and the development community must invest
$40,084,500 in extension of new interceptors and trunk sewers into currently unsewered areas,
and in replacement and/or parallel interceptor and trunk sewers to accommodate the expanded
Service Area. Also during this period, the development community and individual home owners
will invest approximately $80,000,000 to $100,000,000 in construction of collection system
pipelines of 10 -inches in diameter or less.
FUTURE FINANCING
Financial options available to the City of Yakima for financing both mandatory and non-
mandatory obligations for expansion and continued operations of the interceptors and treatment
facilities are currently being developed in a Cost -of -Service Study. The Cost -of -Service Study
will include capital costs, annual operations and maintenance expenses, and staffing obligations.
Compliance with federal and/or state mandatory regulations requires adequate funding
sources regardless of ability to pay. Although the federal and/or state regulatory agencies
sometimes provide partial funding for mandated improvements in the form of grants and
loans, those resources have been diminished dramatically over the last decade. As a
consequence, the City of Yakima and the Yakima Regional WWTP will be required to use
wholesale and retail revenues to pay a substantial portion (90 percent or more) of the total
costs either as cash or debt payments. The impact to wholesale and retail rates will be
significant.
Present City policy allows funding for mandatory renewals and replacements from
wholesale/retail revenues. As a general financial "rule of thumb" the City of Yakima should be
funding mandatory renewals and replacements from rates at an amount greater than the annual
depreciation expense. Annual depreciation expense reflects the current investment in the
Yakima Regional WWTP and collection system that is being depreciated. The wastewater
treatment plant investment needs to be replaced in order to maintain the existing level of
infrastructure. The 1999 annual depreciation expense for the Yakima Sewer Utility was
approximately $2.9M. Simply funding the annual depreciation expense will not generate
sufficient revenues to replace the existing or depreciated facility.
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HDR ENGINEERING, INC.
CITY OF YAKIMA
OCTOBER 25, 2000 PAGE 5
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DRAFT
Growth related facilities are generally funded with new financial resources generated from
property assessments, connection charges, and development fees. Federal and/or state funding
sources are often limited for new construction for growth related facilities. If available, funding
sources are generally limited to replacement of existing infrastructure, promotion of economic
growth of the community, or for resolving a health threat in the area to be served.
CONCLUSION
The City of Yakima has operated a progressive sewer utility serving the needs of the community
since 1936. Over the past 64 years, the City has taken a proactive approach to support the
economic development goals of the region; comply with federal/state laws, rules, and
regulations; and operate and maintain the sewer utility to provide economical and reliable
wastewater service to the region.
The adoption of the Mandatory Wastewater Facilities Plan by the City of Yakima continues the
commitment of the region to the protection of the environment, while providing for growth and
economic development. This long term planning effort should be viewed as a guide to the future
for the Metropolitan Yakima Area. Modifications may be required in the future to accommodate
the region's changes in population, land use regulations, and Service Area characteristics.
•
HDR ENGINEERING, INC.
CITY OF YAKIMA
OCTOBER 25, 2000 PAGE 6
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CITY OF YAKIMA MANDATORY WASTEWATER FACILITES PLAN
SEPA ENVIRONMENTAL CHECKLIST
A. BACKGROUND
1. Name of proposed project, if applicable: Mandatory Wastewater Facilities Plan
2. Name of applicant: City of Yakima
3. Address and phone number of applicant and contact person:
City of Yakima Wastewater Division
2220 East Viola
Yakima WA 98902
Doug Mayo
(509) 575-6077
4. Date checklist prepared: 03 October 2000
5. Agency requesting checklist: City of Yakima
6. Proposed timing or schedule (including phasing, if applicable): Twenty year plan
7 Do you have any plans for future additions, expansion, or further activity related to or connected
with this proposal? If yes, explain.
The 20 year Plan is broken into three phases of 6 to 8 years in length. The first phase is expected to
start in 2001 and includes maintenance / upgrades to the treatment plant and collection system. The
upgrades are divided between mandatory and safety / renewal. Additionally the collection system
will be expanded in the Urban Reserve Area. Overloaded pipes in the Yakima Urban Area will be
upgraded to meet current / future demands. Phases II and III will continue the expansion of the
wastewater treatment plant as well as the collection system. These planned upgrades and
maintenance actions will service an expected increase in population of approximately 85,000 to a
total service area population of approximately 165,000 at build -out conditions.
8. List any environmental information you know about that has been prepared, or will be prepared,
directly related to this proposal.
City of Yakima Comprehensive Sewer Plan
City of Yakima Wastewater Facility Plan
9. Do you know whether applications are pending for governmental approvals of other proposals
directly affecting the property covered by your proposal? If yes, explain.
No. All property covered by this proposal is within the boundanes of the Yakima Urban Growth
Boundary. This area encompasses Yakima city limits, the Yakima Urban Service Area, the Urban
Reserve Area and the Suntides / Gleed Basin (Figure 1).
Page 1 of 18
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5
4
3
2
1
D
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B
A
2000
SCALE
LEGEND:
SCALE
0 2000
4000
FEET
EXISTING SANITARY SEWER PIPING
PARALLEL PIPES REQUIRED
WIDE HOLLOW BASIN INTERCEPTOR
SUMMITVIEW AVENUE
TIETON DRIVE
WIDE HOLLOW ROAD
c_t
S 72ND AVENUE
WI NOB HILL BOULEVARD
ZIER ROAD
COWICHE CANYON BASIN INTERCEPTOR
FRUITVALE BOULEVARD
SUNTIDES/GLEED BASIN TRUNK
S 40TH AVENUE
-��--- _?' �COOLIDGE BASIN INTERCE
AHTANUM ROAD
W WASHINGTON AVENUE
OR
WILEY CITY BASIN TRUNK
5 16TH AVENUE
AIRPORT WEST BASIN LATERALS
W UNCOLN AVENUE
E YAKIMA AVENUE
11111 ILL BOULEVARD
1111111
E MEAD AVENUE
1n.
INTERSTATE 82
AHTANUM ROAD
YAKIMA
REGIONAL WWTP
RUDKIN ROAD
HDR Engineering, Inc.
1
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
THIS UNE IS ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE INCH. SCALE ACCORDINGLY.
0
0
n
0
z
BUILD -OUT
COLLECTION
SYSTEM
IMPROVEMENTS
Figure Number
FIGURE 1
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10. List any government approvals or permits that will be needed for your proposal, if known.
City of Yakima Building Permit
City of Yakima Grading Permit (incorporated into Building Permit)
City of Yakima Substantial Development Permit (Shoreline Permit) (depending upon the placement
of trunks and collectors)
City of Yakima Right of Way Permit
State of Washington Electrical Permit
State of Washington NPDES Permit Modification
11. Give brief, complete description of your proposal, including the proposed uses and the size of
the project and site. There are several questions later in this checklist that ask you to describe certain
aspects of your proposal. You do not need to repeat those answers on this page. (Lead agencies may
modify this form to include additional specific information on project description.)
This is a Mandatory Wastewater Facilities Plan as required by the Growth Management Plan (RCW
36.70A.215) and the Washington Department of Ecology. The Plan describes the planning,
findings, and recommendations for the City of Yakima Collection system and the Yakima
Regional Wastewater Treatment Plant 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.
12. Location of the proposal. Give sufficient information for a person to understand the precise
location of your proposed project, including a street address, if any, and section, township, and range,
if known. If a proposal would occur over a range of area, provide the range or boundaries of the
site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably
available. While you should submit any plans required by the agency, you are not required to
duplicate maps or detailed plans submitted with any permit applications related to this checklist.
Within a twenty year growth boundary for the Yakima Urban Area (Figure 2). The Yakima Regional
WWTP will be expanded at its present site located on the east side of I-82 and south of SR 24
(Moxee Highway). Interceptors and collection system pipelines will be constructed throughout the
Urban Growth area as development extends into these areas.
Page 3 of 18
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A
6 1 5 1 4 1 3 1 2 1 1
UGSA
SCALE
2500 0 2500
FEET
LEGEND:
5000
DRAINAGE BASINS
FER
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIIM 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 5 FULL SIZE IF NO
ONE INCH. SCALE ACCORDING!
0
YAK MA URBAN
AREA DRAINAGE
SUBBASIN
BOUNDARIES
Figure Number
FIGURE ;
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B. ENVIRONMENTAL ELEMENTS
1. Earth
a. General description of the site (circle one): Flat, rolling, hilly, steep slopes, mountainous,
other
The treatment plant site is flat. The service area slopes range from flat to steep.
b. What is the steepest slope on the site (approximate percent slope)?
The treatment site area is generally flat with only a 1-2% slope. The service area includes slopes up to 20% or
greater
c. What general types of soils are found on the site (for example, clay, sand, gravel, peat,
muck)? If you know the classification of agricultural soils, specify them and note any prime
farmland.
The lower elevations, along the Naches and Yakima Rivers, are primarily Weirman-Naches-Ashere series
which are well drained, level to gently sloping, consisting of flood deposits. To the west, soils change to the
Ritzville-Warden-Starbuck series and then to the Harwood-Gorst-Cowiche senes. These series range in depth
to very shallow to quite deep, well drained, level to very steep. To the south of Yakima and west of Union
Gap, along Wide Hollow Creek, is the Umapine-Esquatzel series which are deep, well drained to poorly
drained, level to moderately steep. They are found on terraces and floodplains.
d. Are there surface indications or history of unstable soils in the immediate vicinity? If so,
describe.
According to the Yakima Urban Area Comprehensive Plan, areas exist which are oversteepened and therefore
high risk.
e. Describe the purpose, type, and approximate quantities of any filling or grading proposed.
Indicate source of fill.
The treatment plant improvements will require site preparation and excavation for utilities and structures but
only minor fill material will be required. New trunks and laterals will be excavated and then backfilled first
with bedding matenal then native excavated material. No additional fill is expected.
f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe.
No erosion is expected during nominal construction operations. Some wind erosion may occur during
construction which can be controlled by water application. This will preclude wind blown dust.
g. About what percent of the site will be covered with impervious surfaces after project
construction (for example, asphalt or buildings)?
• The treatment plant site is approximately 25 acres in size. Buildmg and impervious surfaces cover 60% of the
site. Improvements are expected to cover 4 acres thereby increasing the impervious surface cover to 75%.
Page 5 of 18
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h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any:
During construction of the treatment plant, disturbed areas can be watered to reduce dust and wind erosion.
After construction, areas not slated for impervious surfaces will be seeded and watered.
During the construction of trunks and laterals, excavated materials can again be watered to prevent wind
erosion. After construction, the surface will be returned to pre-existing conditions.
2. Air
a. What types of emissions to the air would result from the proposal (i.e., dust, automobile, odors, industrial
wood smoke) during construction and when the project is completed? If any, generally describe and give
approximate quantities if known.
Some dust will be generated during construction. The construction equipment itself will emit carbon monoxide
and nitrogen oxide. These will be controlled by equipment emissions controls in accordance with
manufacturer's specifications. After completion of plant construction, air emissions would be accommodated
by current operational practices. Barren areas will be returned to pre-existing conditions by reseeding.
b. Are there any off-site sources of emissions or odor that may affect your proposal? If so, generally
describe.
No
c. Proposed measures to reduce or control emissions or other impacts to air, if any:
During construction, fugitive dust will be controlled through the application of water. The impacts will be
temporary and no long term impacts are expected.
3 Water
a. Surface.
1) Is there any surface water body on or in the immediate vicinity of the site (including year-round and
seasonal streams, saltwater, lakes, ponds, wetlands)? If yes, describe type and provide names. If appropriate,
state what stream or river it flows into.
The treatment plant site is located approximately 500 feet from the Yakima River. The outfall from the
treatment plant is located near RM 112.
Some new trunks and laterals may be installed near other waterways. They will be buried following
completion of the construction (Figure 3)
Page 6 of 18
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5000
SCALE
0 5000
10000
LEGEND:
FEET
WETLANDS
FER
HDR Engineering, Inc.
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CITY OF YAKIMA
YAK !IAA 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 LINE IS ONE INCH WHEN
DRAWING S FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
YAK MA URBAN
AREA WETLANDS
Figure Number
FIGURE 3
• 2) Will the project require any work over, in, or adjacent to (within 200 feet) the described waters? If yes,
please describe and attach available plans.
Some work will be performed on the outfall structure. This involves working on the gate and some operational
repairs at the outlet box Trunks and laterals may be placed within 200 feet of various waterways (Figure 3).
3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or
wetlands and mdicate the area of the site that would be affected. Indicate the source of fill material.
No fill or dredge matenal will be involved in this project.
4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and
approximate quantities if known.
No.
5) Does the proposal lie within a 100 -year floodplain? If so, note location on the site plan.
The outfall for the treatment plant lies within the 100 year floodplain. The remainder of the treatment plant has
been constructed above the 100 year floodplain. The trunks and laterals to be constructed will generally be
constructed outside of FEMA floodplain designations. Pipelines constructed within the 100 -year boundary will
be protected. The floodplains are designated as protected under the Growth Management Plan.
• 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of
waste and anticipated volume of discharge.
The treatment plant currently discharges up to 14.4 million gallons per day (average daily flow) and 24.0
million gallons per day (maximum daily flow) of secondary effluent into the Yakima River. With completion
of all proposed improvements, flow will be increased to 17.9 million gallons per day (average daily flow) and
38.0 million gallons per day (maximum daily flow).
b. Ground:
1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description,
purpose, and approximate quantities if known.
No.
2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if any
(for example: Domestic sewage; industnal, containing the following chemicals... ; agricultural; etc.).
Describe the general size of the system, the number of such systems, the number of houses to be served (if
applicable), or the number of animals or humans the system(s) are expected to serve.
No waste material will be discharged onto the ground. The improvements will increase the capacity of the
treatment plant and extend the service area which will eliminate septic systems. This will have a net positive
effect by removing potential contaminants from infiltrating into the groundwater.
. c. Water runoff (including stormwater):
Page 8 of 18
•
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1) Describe the source of runoff (including storm water) and method of collection and disposal, if any
(include quantities, if known). Where will this water flow? Will this water flow into other waters? If so,
describe.
Runoff in this area is caused by rainstorms and snowmelt. It is collected in a separate storm water system
which historically served as a subsurface drain for groundwater. It has evolved mto a surface water system and
handles storm water, groundwater, irrigation and industrial cooling water.
Runoff at the treatment plant is collected at the plant pumping station and processed in the treatment system.
2) Could waste materials enter ground or surface waters? If so, generally describe.
No.
d. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any:
The proposed collection system will eliminate existing septic systems and provide for regional sewer service to
new development as it occurs.
4. Plants
a. Check or circle types of vegetation found on the site:
X deciduous tree: alder, maple, aspen, other
X evergreen tree. fir, cedar, pine, other
X shrubs
X grass
X pasture
X crop or gram
X wet soil plants. cattail, buttercup, bullrush, skunk cabbage, other
X water plants: water lily, eelgrass, milfoil, other
X other types of vegetation (riparian plants where the outfall enters the river)
b. What kind and amount of vegetation will be removed or altered?
Grass may be disturbed during treamient plant construction. Other vegetation will be disturbed when placing
the trunks and laterals. Areas will be revegetated upon completion of construction.
Page 9 of 18
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•
c. List threatened or endangered species known to be on or near the site.
Plant Listing
Scientific
Name
Common
Name
State
Status
Federal
Status
Astragaluscolumbianus
Cypripedum fasciculatum
Erigeron Basalticus
Lobelia Kalmii
Lomatium Tuberosum
Sisyrinchium Sarmentosum
Tauschia Hooveri
SC = Species of Concern.
C = Candidate.
Columbia milk -vetch
Clustered lady's-slipper
Basalt Daisy
Kalm's lobelia
Hoover's desert -parsley
Pale blue-eyed grass
Hoover's tauschia
E = Endangered.
Threatened
Threatened
Threatened
Endangered
Threatened
Threatened
Threatened
SC
SC
C
E
SC
SC
SC
d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the
site, if any:
The treatment plant will be revegetated as needed. Trees and berms may also be used for screening.
Vegetation removed during construction of trunks and laterals will be replaced once construction is completed.
5. Animals
a. Circle any birds and animals which have been observed on or near the site or are known to be on or near
the site:
birds: hawk, heron. eagle, songbirds, other. ducks, pheasant
mammals: deer, bear, elk, beaver, other: skunks, coyote
fish. bass. salmon, trout, herring, shellfish, other:
b List any threatened or endangered species known to be on or near the site.
Bald Eagle
Ferruginous Hawk
Golden Eagle
Great Blue Heron
Prairie Falcon
Ring Necked Snake
Fish:
Salmon
Steelhead
c. Is the site part of a migration route? If so, explain.
Possible. Salmon and steelhead migrate on the Yakima River. Waterfowl migrating on the Pacific Flyway use
the rivers, sloughs and nearby agricultural lands.
d. Proposed measures to preserve or enhance wildlife, if any:
Page 10 of 18
• Efforts will be made to avoid areas currently designated as fish and wildlife conservation areas. These areas are
not planned for construction and are incorporated into urban areas as protected.
6. Energy and natural resources
a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed
project's energy needs? Describe whether it will be used for heating, manufacturing, etc.
Electncal power from Pacific Power and Light is currently used at the treatment plant and pumping stations.
Improvements include upgrading the backup generator to natural gas or fuel oil . If natural gas were used, a
natural gas line would be added to the facility. Methane generated at the treatment plant is currently used for
operational needs and building heat. As the facility grows, the heat demand may outpace gas production.
Another boiler may be added which will be fueled by fuel oil. As the service area population increases, there
will be an increase in demands on all services.
b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally
describe.
No
c. What kinds of energy conservation features are included in the plans of this proposal? List other
proposed measures to reduce or control energy impacts, if any:
• The treatment plant improvements will increase electrical efficiency. Methane gas, generated by the digesters,
•
will be used for building heating and operational needs. High efficiency motors are used on all equipment.
7. Environmental health
a Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and
explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe.
The plant uses chlorine for disinfection of the effluent and sulfur dioxide for dechlorination. Procedures for
handling these materials are provided in the Operation and Maintenance (O&M) Manual. Use of chlorine may
be eliminated if the City decides to use ultraviolet disinfection.
1) Describe special emergency services that might be required.
The City of Yakima has prepared and implemented a Risk Management Plan (RMP) and a Process Safety
Management Plan (PSM) which directs the storage, handling, and use of chemicals at the Yakima Regional
WWTP.
2) Proposed measures to reduce or control environmental health hazards, if any:
Chlorine usage is currently provided with containment and treatment.
Page 11 of 18
•
b. Noise
1) What types of noise exist in the area which may affect your project (for example: traffic, equipment,
operation, other)?
None.
2) What types and levels of noise would be created by or associated with the project on a short-term or a
long-term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come
from the site.
Construction will cause increased noise levels during the short term. These activities would generally be
limited to normal work hours of 7:00 AM to 6:00 PM. Operation of the facility will not increase noise levels
for the long terms.
Noise generated by equipment used during construction of the trunks and laterals will be muffled per
manufacturer's recommendations and will be governed by WAC 173-62 and City of Yakima Penal Code,
Chapter 6.04. Activities will generally occur during normal work hours.
3) Proposed measures to reduce or control noise impacts, if any:
Construction equipment will comply with manufacturer's specifications for noise limitation. Construction
activities will generally be limited to daylight hours. Any operational equipment which might cause a noise
impact will be inside or enclosed.
8. Land and shoreline use
a. What is the current use of the site and adjacent properties?
The treatment plant site is currently used for wastewater treatment. To the east is the Yakima River. The
interstate forms the western boundary. The land to the south of the treatment plant is used for land application
of food processing wastewater and is owned by the city.
b. Has the site been used for agriculture? If so, describe.
The site may have been used for agriculture in the past. The plant has been operating on the current site since
1936.
Lands within the proposed expanded service area may have been used for agriculture in the past however
industrial, commercial and residential development has changed the land use over time. The land within the
sewer service area is within the City of Yakima's Urban Growth Boundary.
c. Describe any structures on the site.
Current structures at the treatment plant include: primary and secondary clarifiers, trickling filters, aeration
basins, anaerobic digesters, secondary digesters, headworks building, grit channels, pump station, chlorination
facility, solids building, laboratory and offices.
d. Will any structures be demolished? If so, what?
Page 12 of 18
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•
No. All current structures are expected to remain and will be incorporated into the expansion.
e. What is the current zoning classification of the site?
It is zoned Suburban Residential. The service areas are a mixture of zoning classifications.
f What is the current comprehensive plan designation of the site?
The treatment plant site is categorized as low density residential. The rest of the city is a mixture of residential,
commercial, and industrial.
g. If applicable, what is the current shoreline master program designation of the site?
This question does not apply to treatment plant improvements. Some of the trunk and lateral installation may
occur within 200 feet of the shoreline. The designation of the shoreline, inside the city, is protected.
h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify.
There are areas designated as sensitive areas within the Yakima Service Area (Figure 3 and Figure 4). These
includes wetlands, groundwater recharge areas, conservation areas, and geologically hazardous areas.
i. Approximately how many people would reside or work m the completed project?
Based upon current estimates, the population in year 2020 in the Yakima Urban Service Area will be 102,000,
the Union Gap Urban Service Area will be 8,500, the Terrace Heights Urban Service Area 8,500
people and the Yakima Urban Reserve would be 23,400 Currently there are 79,000 in the Yakima Urban
Service area, 6,500 in the Union Gap Service Area, 4,700 in the Terrace Heights area and 3,000 in the Yakima
Urban Reserve.
j. Approximately how many people would the completed project displace?
None.
k. Proposed measures to avoid or reduce displacement impacts, if any:
None are proposed since there are no plans to displace people.
1. Proposed measures to ensure the proposal is compatible with existing and projected land
uses and plans, if any:
The treatment facility, trunk, and lateral lines comply with the current zoning and land use designations. The
basis for the proposed improvements is to provide wastewater services for the current and projected land use.
Page 13 of 18
•
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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
Dote
FEBRUARY 2000
I I
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HABITAT AREAS
Figure Number
III 9. Housing
a. Approximately how many units would be provided, if any? Indicate whether high, middle, or
low-income housing.
None as a direct result of this project. The project will result in additional housing units being able to obtain
sewer service as the trunks and laterals are extended and the plant capacity is increased.
b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or
low-income housing.
None.
c. Proposed measures to reduce or control housing impacts, if any:
None are proposed. Projects outlined in this Plan may allow current housing quantities to increase to presently
undeveloped areas within the City's Urban Growth Boundary m accordance with current zoning and
comprehensive plans.
10. Aesthetics
a. What is the tallest height of any proposed structure(s), not including antennas, what is the
principal exterior building material(s) proposed?
• Depending upon the alternative selected, the highest building would be the solids building. It is expected to be
30 feet tall. Other improvements would be at the same height or lower than existing structures.
•
b. What views in the immediate vicinity would be altered or obstructed?
None.
c. Proposed measures to reduce or control aesthetic impacts, if any:
Areas disturbed during construction, where possible, will be reseeded and revegetated..
11. Light and glare
a. What type of light or glare will the proposal produce? What time of day would it mainly occur?
The treatment plant site will continue to be lighted for safety and security. No off site lighting will occur
following construction of the project.
b. Could light or glare from the finished project be a safety hazard or interfere with views?
No changes in lighting are anticipated therefore no impacts are expected.
c. What existing off-site sources of light or glare may affect your proposal?
None.
Page 15 of 18
•
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•
d. Proposed measures to reduce or control light and glare impacts, if any:
None.
12. Recreation
a What designated and informal recreational opportunities are in the immediate vicinity?
There is an arboretum located to the north and a state park to east of the treatment plant site. Across the
interstate to the northwest, there is another City park. Throughout the service area, there are numerous parks
and recreational opportunities along the Yakima River and other surface waters.
b. Would the proposed project displace any existing recreational uses? If so, describe.
No. There are no plans to displace any recreational uses / areas due to the project
c. Proposed measures to reduce or control impacts on recreation, including recreation
opportunities to be provided by the project or applicant, if any:
None.
13. Historic and cultural preservation
a. Are there any places or objects listed on, or proposed for, national, state, or local preservation
registers known to be on or next to the site? If so, generally describe.
There are historic buildings associated with the history of the city and county throughout the area The project
will avoid any impacts to these sites.
b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural
importance known to be on or next to the site.
None will be impacted by the proposed project.
c. Proposed measures to reduce or control impacts, if any:
None.
14. Transportation
a Identify public streets and highways serving the site, and describe proposed access to the existing
street system. Show on site plans, if any.
The treatment plant is accessed from East Viola Avenue. The trunk and lateral lines will follow a number of
streets throughout the expanded service area. All streets will be returned to their preconstruction condition, or
better, following the construction.
Page 16 of 18
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b. Is site currently served by public transit? If not, what is the approximate distance to the nearest
transit stop?
The site and the Yakima Urban Area is currently served by public transit. There is a mass transit stop near the
treatment plant.
c. How many paridng spaces would the completed project have? How many would the project
eliminate?
The current site has 40 spaces. An additional 10 spaces are expected to be added for a total of 50 spaces.
d. Will the proposal require any new roads or streets, or improvements to existing roads or streets,
not including driveways? If so, generally describe (indicate whether public or private).
No. Existing streets will be used for this project. After construction, all streets will be returned to their
preconstruction condition.
e. Will the project use (or occur m the immediate vicinity of) water, rail, or air transportation? If so,
generally describe.
The project construction is not expected to occur near water, rail, or air transportation.
f. How many vehicular trips per day would be generated by the completed project? If known,
indicate when peak volumes would occur
The project will result m 20-25 additional trips per day. These trips will be mainly employee trips which occur
from 7:00 AM to 5.00 PM. Delivery vehicles trips at the wastewater treatment plant are expected to increase
by 3-5 per day
As the service area population increases during the 20 year period, vehicle trips will increase in direct
proportion to growth.
g. Proposed measures to reduce or control transportation impacts, if any:
Traffic control personnel will provide direction at all construction sites on or near roadways.
Regional planning will address needs for additional roadway improvements throughout the service area.
15. Public services
a. Would the project result in an increased need for public services (for example: fire protection,
police protection, health care, schools, other)? If so, generally describe.
No. The treatment plant and collection system upgrades will be m response to additional development. The
new development may cause an increased need for all public services.
b. Proposed measures to reduce or control direct impacts on public services, if any.
None. All development will comply with zoning and comprehensive plans.
Page 17 of 18
16. Utilities
a. Circle utilities currently available at the site: electricity, natural gas, water, refuse service,
telephone, sanitary sewer, septic system, other.
b. Describe the utilities that are proposed for the project, the utility providing the service, and the
general construction activities on the site or in the immediate vicinity which might be needed.
The proposed improvements at the wastewater treatment plant will include additional electrical power supplies
and may include natural gas or fuel oil as well, depending upon the option selected. The natural gas or fuel oil
may be used for standby power generation.
C. SIGNATURE
The above answers are true and complete to the best of my knowledge. I understand that the lead
agency is relying on them to make its decision.
Signature. / i c,
Jr\r
Doug Mayo, IDivision Manu
Zc
Date Submitted:
•
•
Page 18 of 18
DRAFT
• City of Yakima
•
•
Mandatory Wastewater Facilities Plan
SECTION 1
Summary
October 2000
prepared by
Tony Krutsch
HDR Engineering, Inc.
reviewed by
John Koch
City of Yakima
•
•
•
DRAFT
Table of Contents
1.1 Background 1
1.2 Regulatory Issues 2
1.3 Service Area Characteristics 8
1.4 Wastewater Flows and Loadings 8
1.5 Analysis of Existing Wastewater Treatment Plant 10
1.6 Identification of Selected Wastewater Treatment Strategies 11
1.6.1 Septage Handling 12
1.6.2 Headworks/Pretreatment 12
1.6.3 Primary Treatment Alternatives 12
1.6.4 Trickling Filters 12
1.6.5 RAS/WAS Pumping 12
1.6.6 Secondary Clanfier 13
1.6.7 Aeration Basins 13
1.6.8 Disinfection 13
1.6.9 Waste Activated Sludge 13
1.6.10 Key Features 13
1.6.11 Resource Requirements 14
1.7 Aeration Basin Structural Evaluation 16
1.8 Gas Utilization and Cogeneration 16
1.9 Biosolids Management 17
1.9.1 Digester Capacity 17
1.9.2 Secondary Handling of Centrate 17
1.9.3 Biosolids Dewatenng/Drying Alternatives 18
1.9.4 Polymer Addition Alternatives 18
1.9.5 Solids Handling Building 18
1.9.6 Biosolids Utilization Alternatives 18
1.9.7 Resource Requirements 19
1.10 Analysis of Existing Wastewater Collection Facilities 19
1.10.1 Stormwater Program 20
1.11 Identification of Selected Wastewater Collection Strategies 21
1.11.1 Existing System Deficiencies 22
1.11.2 Buildout System Deficiencies 22
1.11.3 New Interceptors/Trunk Sewers 22
1.11.4 Impact of Growth in the Urban Reserve 22
1.11.5 Miscellaneous Collection System Projects 22
1.12 Financial Planning/Implementation 23
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE i
DRAFT
• City of Yakima
•
•
SECTION 1
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 tnckling 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 Distnct,
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 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 Wastewater Treatment Plant 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, tnckling 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).
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 1
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DRAFT
➢ Upgraded the facility nonpotable water system, rehabilitated the screening and
degntting area, enclosed the screening and degritting area for control of air
emissions with discharge of captured air to the tnckling filters and wet -scrubbers,
installation of flexible domes over secondary digesters for methane gas
containment, and rehabilitation of pnmary digesters with fixed covers and
mechanical mixing (1998).
In addition to these major improvements at the Yakima Regional Wastewater Treatment
Plant, 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 Mandatory Wastewater Facilities Plan describes the planning, findings, and
recommendations for the City of Yakima Collection system and the Yakima Regional
Wastewater Treatment Plant 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 Regulatory Issues
Regulatory and permitting issues that influence wastewater facility planning were
assessed in Section 2 of.this report. The Yakima Regional Wastewater Treatment Plant
currently operates under a National Pollutant Discharge Elimination System (NPDES)
permit issued by the WDOE on September 8, 1997. A copy of the NPDES Permit and the
WDOE worksheet prepared in development of the permit are included in Appendix A.
In negotiations with the WDOE for the renewal of the 1997 NPDES permit, the City staff
was able to make modifications to the language and requirements of a DRAFT permit
which avoided and deferred the requirement for tertiary treatment of the wastewater
effluent prior to discharge to the Yakima River. The opinion of probable cost of tertiary
treatment ranged from $30 to $40 million, with an annual operations and maintenance
cost increase of $2 to $3 million.
Over the past 50 to 60 years, the laws, rules, regulations, and requirements of both the
federal and state government, relating to public health, have increased significantly. The
Code of Federal Regulations (CFR) for the United States currently contains 50 Titles that
in some way effect daily lives of all citizens. Title 40 of the CFR is entitled "Protection
of Environment" and sets forth the laws, rules, regulations, and requirements of the
Environmental Protection Agency.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 2
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DRAFT
The pnmary subchapters of Chapter I of Title 40 include the following:
Subchapter A
Subchapter B
Subchapter C
Subchapter D
Subchapter E
Subchapter F
Subchapter G
Subchapter H
Subchapter I —
Subchapter J
Subchapter K
Subchapter N
Subchapter 0
Subchapter P
Subchapter Q
Subchapter R
— General
— Grants and Other Federal Assistance
— Air Programs
— Water Programs
— Pesticide Programs
— Radiation Protection Programs
— Noise Abatement Programs
— Ocean Dumping
Solid Wastes
— Super fund, Emergency Planning, and
Community Right -to -know Programs
thru M — Reserved
— Effluent Guidelines and Standards
— Sewage Sludge
— Reserved
— Energy Policy
— Toxic Substances Control Act
Subchapter D — Water Programs, which affects wastewater treatment plant discharge of
treated effluent to the environment, contains 30 Articles including:
Article 125 — Criteria and Standards for the National Pollutant Discharge
Elimination System
Article 129 — Toxic Pollutant Effluent Standards
Article 130 — Water Quality Planning and Management
Article 131 — Water Quality Standards
Article 133 — Secondary Treatment Regulation
Subchapter D — Water Programs contains over 1131 pages of text in setting the laws,
rules, regulations and requirements of this single issue.
A complete listing of all 50 Titles under the CFR are included in Appendix B. A listing
of Chapters and Subchapters of Title 40 — Protection of the Environment, Title 42 —
Public Health, and Title 50 — Wildlife and Fishenes are included to provide a perspective
of the depth of laws, rules, regulations, and requirements that have been adopted.
Compliance with the requirements of the Code of Federal Regulations is mandatory by all
citizens of the United States. Non compliance can be considered as a criminal act subject
to significant fines and incarceration upon conviction.
In accordance with the rights reserved to states under the Tenth Amendment of the
Constitution, and not to be outdone by the adoption of laws, rules, regulations, and
requirements of the federal government, the State of Washington has also established
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 3
DRAFT
their own legislation which effects the daily lives of the citizens of the state. The Revised
Code of Washington (RCW) identifies the laws of the State.
Once a law (RCW) has been adopted by the state legislature, the rules, regulations, and
requirements for implementation of the RCW are developed by the specific agency
considered to jurisdiction. These rules, regulations, and requirements are identified as
Washington Administrative Code (WAC). The WDOE has developed and/or participated
in the development of 161 WACs. On an annual basis, many of the WACs are revised,
modified, changed, corrected, or added to; to reflect changes in federal and/or state
regulations; to reflect the opinion of WDOE; to respond to either known or perceived
concerns with existing WACs; or to reflect the opinion of specific interest groups. Of the
161 WACs currently indexed by WDOE, 42 are currently under review for revision,
modification, change, correction, or addition. A complete listing of WACs for WDOE
are included in Appendix C.
Both the Washington State Legislature and WDOE have elected to develop, adopt, and
implement RCWs and WACs which are often times more onerous and restrictive than
those adopted by the Federal Legislature and EPA. The primary law (RCW) which
effects wastewater treatment plant discharge of treated effluent to the environment is
RCW 90.48. This RCW is also considered by WDOE to be pnmary law for the control
of stormwater discharge. A copy of RCW 90.48 has been included in Appendix C.
The pnmary rules, regulations, and requirements developed by WDOE as WACs for
wastewater treatment plant discharge of treated effluent to the environment and those
which impact stormwater disposal include the following:
WAC 173-200:
WAC 173-201A:
WAC 173-204:
WAC 173-218:
WAC 173-221A:
WAC 173-308:
Water Quality Standards for Ground Waters of the State of
Washington
Water Quality Standards for Surface Waters of the State of
Washington
Sediment Management Standards
Underground Injection Control Program
Wastewater Discharge Standards and Effluent Limitations
Biosolids Management
A copy of each of these WACs has been included in Appendix C. Compliance with the
requirements of the Revised Code of Washington is mandatory by all citizens of the State.
Non compliance can be considered as a criminal act subject to significant fines and
incarceration upon conviction.
In order to assess current and future NPDES permit requirements, and other regulatory
requirements, that appear to effect the future wastewater utility, the Washington
Department of Ecology was contacted during the earlier stages of preparation of this
Mandatory Wastewater Facilities Plan. Both current and anticipated regulatory
requirements which influenced the planning for improvements were considered. Table 1-
1 presents a summary of these issues.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 4
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Table 1-1. Summary of Anticipated Regulatory and Permitting Issues
Regulatory
Issue/Parameter
Issues and Current Status
Effluent Discharge
WWTP Flow
BOD and TSS
Phosphorus
Total Nitrogen
Ammonia Nitrogen
Chlorine Residual
Bacteria
Metals
Biomonitoring
Infiltration/Inflow
Biosolids
Virus Control
Wastewater Treatment Facility permitted flow (22.3 mgd, daily average — max. month).
Secondary treatment standards (30/30 and 85% removal)
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 the 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/1 monthly ave., 0.029 mg/1 daily max).
Fecal coliform limits (200/400 organisms per 100 mis) (May be modified to e -coli in future)
Elevated levels of Silver, Mercury, Copper, and Lead in upper river from historic mining activity
BMPs required for local commercial/industrial sources. Metals are of high importance under
pretreatment program.
Whole effluent toxicity testing required for acute and chronic toxicity
Collection system rehabilitation projects have reduced I&I. Infiltration is related to seasonal use
of irrigation system in the community
Biosolids management must meet 40 CRF 503, biosolids standards.
May have stricter requirements in the future as analytical methods improve.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
NPDES Permit
Limits'
Y
C,M
N
N
C
C
C
N
Y
S
S
N
Importance to
Planning
High
Moderate
Moderate
Moderate
High
High
High
Moderate
High
High
Moderate
Moderate
PAGE 5
•
•
DRAFT
Table 1-1. Summary of Anticipated Regulatory and Permitting Issues (Cont)
Regulatory
Issue/Parameter
Issues and Current Status
NPDES Permit
Limits1
Importance to
Planning
Effluent
TMDL and Watershed
Planning
Chlorine Byproducts
Effluent Reclamation and
Reuse
Treatment Plant
Air Emissions
Air Toxics
Air Contaminants
Visual Appearance
Noise Control
Spravfield Discharge
Sprayfield Flow
BOD and TSS
Bacteria
TKN
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
Regulations apply to VOCs, H2S, C12, but not likely to be considered major source.
Clean Air Act Section 112r Risk Management Plan (RMP) requirements had compliance deadline
of June 21, 1999 New regulations proposed by EPA on Urban air toxics may become an issue in
the future.
Yakima County Clean Air Authority potential Title V Permit. Model run indicated 609 lbs. of
pollutants discharged into the air. This is below the permitting threshold.
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.
Maintenance of good neighbor policy has high priority City of Yakima regulatory requirements
apply
Food Processing Waste Sprayfield permitted flow (0 75 mgd)
TBD2
Total Coliform Limit TBD2
TBD2
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
N
N
Moderate
Moderate
Moderate
Low
High
Low
High
High
High
High
High
High
PAGE 6
•
•
DtFT
Table 1-1. Summary of Anticipated Regulatory and Permitting Issues (Cont)
Regulatory
Issue/Parameter
Issues and Current Status
NPDES Permit
Limits'
Importance to
Planning
PH
TBD2
N
High
Land Application
Future Limits for the application of food processing waste at the Sprayfield will be determined by
S
High
WDOE2 Setbacks, fencing and compatibility with greenway trails are issues of concern.
Endangered Species Act
Salmon
Legislation relating to salmon recovery in Washington has the potential to significantly impact
wastewater discharges, water conservation, and management of instream flows.
N
Moderate
Other
Other ESA listings in Yakima County are identified in the text.
N
Low
Pretreatment
The Yakima Regional WWTP Pretreatment program is currently a "Partial Pretreatment Program"
Y
High
The City is required to apply for full delegation prior to the next permit cycle which begins June
30, 2002.
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 II Stormwater Permitting program has potential designations for small urban areas with
populations of 10,000 or more with permits required by February, 2003 Regulated small
municipal separate storm sewer systems are to have programs developed and implemented by
Y
High
2008 Stormwater loadings to the Yakima River consume shared assimilative capacity Inflow
reduction efforts to reduce peak wastewater loadings may increase stormwater loadings and
infrastructure requirements.
2
Anticipated content of renewed NPDES discharge permit, coded as follows.
Y, Yes included
N, No, not included
C, Concentration Limit
M, Mass Limit
S, Supplementary Condition
TBD means " to be determined" by the Washington State Department of Ecology prior to the expiration date of the permit, and based on the Sprayfield Engineering Report
(condition S 11 of the permit). The Limits may be set by Administrative Order
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 7
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1.3 Service Area Characteristics
Section 3 of this report describes current and projected population for the Yakima Urban
Area, Yakima Urban Reserve Area, the Union Gap Urban Growth Area, and the Terrace
Heights Urban Service Area. Table 1-2 summarizes the population estimates for the area
through 2020.
Table 1-2. 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
78,987'
100,0002
102,000
23,013
2.503
9,205
Union Gap Urban Service Area
6,4774
7,9305
8,494
2,017
2.556
791
Terrace Heights Urban Service Area
4,7157
7,3248
8,490
3,775
2.559
1,480
Subtotals
90,179
115,254
118,984
28,805
11,476
Yakima Urban Reserve
3,0001°
13,81211
23,420
20,420
2.503
8,168"
Totals
93,179
129,066
142,404
49,225
19,644
•
•
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 Area 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 1-2 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, currently on septic tanks and drainfields, may also be served by the
Yakima Regional WWTP by the year 2015.
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 Wastewater
Treatment Plant were evaluated in Section 4. The three critical design periods selected
for evaluation included the non -irrigation season (March, when flows are lowest), the
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 8
DRAFT
imgation season (August, when flows are highest), and the industrial influenced season
(October — November, when BOD and TSS loadings are highest). Based on these
characteristics, unit per capita flow and loadings were developed for each period. The
unit flow and loadings are applied to population projections to estimate future flow and
loadings to be treated at the wastewater treatment plant. Unit per capita loadings are
shown in Table 1-3.
Table 1-3. Future Per -Capita Loadings for Yakima WWTP
Design Period
Unit Loadings
Flow BOD, Ib TSS, Ib NH4, lb
gpcd pcd pcd pcd
Annual Average 126 0.22 0.20 0 019
Maximum Day 170 0 42 0.68 0 029
March
30 day 104 0.23 0.20 0 022
Max. Day 123 0.39 0 45 0 029
August
30 day 160 019 019 0017
Max Day 170 0.30 0.36 0 022
October -November
30 day 114 0.31 0.22 0 018
Max Day 139 0 42 0 68 0 024
As the Yakima Regional Wastewater Treatment Plant provides service to the City of
Yakima, City of Union Gap, Terrace Heights Service District, and the unincorporated
area of Yakima County lying west of the Yakima city limits, the future flow and loadings
were distributed to the contributing areas for the year 2020 and for buildout conditions.
Table 1-4 shows this distnbution of population and anticipated wastewater
characteristics.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 9
DRAFT
Table 1-4. Maximum Month Average Daily Distribution of Wastewater
Characteristics
1
From Union Gap General Sewer Plan. The second number shown in the percentage column for BOD and TSS is
based on projecting current unit loadings and population in lieu of the calculated ppd as shown in the UG General
Sewer Plan (ie BOD - 3202 ppd, TSS - 2985 ppd in 2020 and BOD - 7705 ppd, TSS - 7182 ppd at Buildout).
2. From Terrace Heights General Sewer Plan.
3 Anticipated to be proportional to population. Union Gap and Terrace Heights did not report current or projected
loadings for Ammonia.
4 Flows and loads based on calculations in Table 4-5 and 4-6.
The sum of the individual calculations for the Yakima Urban Area, the City of Union
Gap, the Terrace Heights Sewer District, and the Yakima Urban Reserve do not equal the
Total Service Area calculation as developed for this evaluation of the Yakima Regional
WWTP. This variance in the sum of the individual calculations is likely the result of the
methods used in the calculation of the individual service area characteristics. Additional
information regarding the variance is included in Section 4.
1.5 Analysis of Existing Wastewater
Treatment Plant
The capacity for each unit process at the Yakima Regional Wastewater Treatment Plant
was identified in Section 5 and is shown in Table 1-5.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 10
Total
Service
Area
Yakima Urban
Area4
Union Gapl
Terrace Heights2
Yakima Urban
Reserve4
Amount
Percent
Amount
Percent (%)
Amount
Percent
Amount
Percent
(%)
(%)
(%)
Current Conditions
Population
90,179
78,987
87.59
6,477
718
4,715
5.23
0
0
Flow (mgd)
14.38
12.64
87.90
0.76
5.29
0.50
3 48
0
0
BOD (ppd)
23,179
19,747
85 19
2,442
10.54
670
2.89
0
0
TSS (ppd)
20,032
17,377
86.75
2,276
11.36
704
3.51
0
0
Ammonia (ppd)
1,9353
2020 Design Conditions
Population
142,404
102,000
71 63
8,494
5 96
8,490
5 96
23,420
16.45
Flow (mgd)
22.78
16.32
71 64
2.06
9 04
1 49
6.54
3 75
16.46
BOD (ppd)
35,601
25,500
71 63
6,603
18.54/8.99
1,206
3.39
5,855
16.45
TSS (ppd)
31,329
22,440
71 63
6,157
19 65/9.53
1,300
4 15
5,152
16.45
Ammonia (ppd)
3,1333
Buildout Conditions
Population
177,500
106,600
60 06
20,438
11.51
14,145
7 97
36,317
20.46
Flow (mgd)
28 40
17 06
60 07
5 64
19 86
1.92
6.76
5.81
20 46
BOD (ppd)
44,375
26,650
60.06
18,085
40 76/17.36
2,020
4.53
9,079
20 46
TSS (ppd)
39,050
23,452
60 06
16,860
43 18/18.39
2,107
5 40
7,990
20 46
Ammonia (ppd)
3,9053
1
From Union Gap General Sewer Plan. The second number shown in the percentage column for BOD and TSS is
based on projecting current unit loadings and population in lieu of the calculated ppd as shown in the UG General
Sewer Plan (ie BOD - 3202 ppd, TSS - 2985 ppd in 2020 and BOD - 7705 ppd, TSS - 7182 ppd at Buildout).
2. From Terrace Heights General Sewer Plan.
3 Anticipated to be proportional to population. Union Gap and Terrace Heights did not report current or projected
loadings for Ammonia.
4 Flows and loads based on calculations in Table 4-5 and 4-6.
The sum of the individual calculations for the Yakima Urban Area, the City of Union
Gap, the Terrace Heights Sewer District, and the Yakima Urban Reserve do not equal the
Total Service Area calculation as developed for this evaluation of the Yakima Regional
WWTP. This variance in the sum of the individual calculations is likely the result of the
methods used in the calculation of the individual service area characteristics. Additional
information regarding the variance is included in Section 4.
1.5 Analysis of Existing Wastewater
Treatment Plant
The capacity for each unit process at the Yakima Regional Wastewater Treatment Plant
was identified in Section 5 and is shown in Table 1-5.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 10
DRAFT
Table 1-5. Rated Capacity (mgd) of Unit Processes under various Operating
Criteria.
Unit Proc
Parameter Condition Limit Unit Annual March August Oct Peak
Primary Clarifiers
Primary Clarifiers
Trickling Filters
Trickling Filters
OFR Avg 1200
OFR PH 2500
OLR Avg 50
OLR MM 65
Aeration Basins MLSS MM 2200
Aeration System OUR MD 52
Aeration System OUR MM 52
Secondary Clarifiers HRT PH 2
Secondary Clarifiers OFR Avg 600
Secondary Clarifiers OFR PH 1200
Secondary Clarifiers SLR Avg 24
Secondary Clarifiers SLR MM 30
Secondary Clarifiers SLR MD 36
Chlorine Contact Basins HRT Avg 60
Chlorine Contact Basins HRT PH 20
DAF Thickeners SLR Avg 20
DAF Thickeners SLR MM 20
Anaerobic Digester HRT MM 15
Digested Biosolids Holding HRT MM 4
Tank'
Gpd/sf 301
Gpd/sf
lb/kcf/d 13.5
Ib/kcf/d 13 7 26.0 13.8
Mg/L 12.1 22.4 12.3
Mg/L/h 20 4 36.6 24 8
Mg/L/h 23 4 44 0 28.3
Hr
Gpd/sf 18.0
Gpd/sf
Lb/d/sf 18.9
Lb/d/sf 23.5 23.9 23.5
lb/d/sf 28.3 28.7 28.5
min 18.9
min
Ib/d/sf 57 4
lb/d/sf 44.2 95.9 44.8
d 21.3 41 4 22.3
d 29 6 57.7 31 1
Centrifuge2 Flow MM 270 gpm 41.3 23 4 43.5
63 4
31 4
36.5
57 4
Avg = Annual average condition
MM = Maximum month condition (applies to March, August, and October)
MD = Maximum day conditions
PH = Peak hour conditions
HRT = Hydraulic retention time
SLR = Solids loading rate
Flow = Flow
OFR = Overflow rate
OLR = Organic loading rate
OUR = Oxygen uptake rate (aeration system limitations)
1 For the Anaerobic Digesters and Digested Biosolids Holding Tanks (Secondary Digesters), the figures indicate
days of hydraulic retention time for the solids loadings anticipated during the periods shown.
2. For the centrifuge, the figures indicate hours of operation to process digested solids for one week during the
period shown at a dewatering rate of 270 gpm.
Each process area of the Yakima Regional Wastewater Treatment Plant was further
assessed for current conditions, and for safety, reliability, and staff issues regarding
operations and maintenance.
1.6 Identification of Selected Wastewater
Treatment Strategies
Section 6 reviewed a wide range of alternatives for expanding the Yakima Regional
Wastewater Treatment Plan to meet future capacity and regulatory effluent quality
requirements. The following provides a brief descnption of the recommended alternative
for each process area for the 20 -year planning.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 11
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•
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DRAFT
1.6.1 Septage Handling
If the City is mandated to construct a septage handling facility for Yakima County by the
Washington Department of Ecology, a new septage receiving facility located along the
west frontage road is recommended. The new facility would include a completely
enclosed drive-through building with air emission controls, screening equipment, septage
storage tankage, and pumping systems to deliver septage to the primary digesters, and
provisions for sampling and monitoring of each delivered load of septage. The opinion of
probable cost for the Septage Handling facility is $2,079,300.
1.6.2 Headworks/Pretreatment
Upgrades and improvements are needed to the existing grit storage system in the
Headworks Building. Repair of the existing storage hopper with an enhanced vibratory
system is recommended. The opinion of probable cost for the Headworks/Pretreatment
facility is $312,100.
1.6.3 Primary Treatment Alternatives
To provide improved control for distnbution of flows and solids to the primary clarifiers,
a new primary clarifier flow split structure is recommended. The opinion of probable
cost for this facility is $870,500.
1.6.4 Trickling Filters
The trickling filter process includes three recommendations: 1) replace the existing
distributors; 2) replace the existing rock media with plastic media, and; 3) enhance forced
ventilation in the trickling filters. Each recommendation is intended to increase the
biological capacity of the tnckling filters. The benefits and timing of enhanced tnckling
filter performance were weighed in conjunction with process expansion alternatives for
the activated sludge system. The replacement of the existing distributors for each
trickling filter was recommended in all alternatives evaluated and has been shown as a
key feature project. The opinion of probable cost for replacement of the existing tnckling
filter mechanisms is $782,500. The opinion of probable cost for the plastic media is
$1,699,100, and the opinion of probable cost for the enhanced forced ventilation is
$1,066,100.
1.6.5 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
existing aeration basins and a future aeration basin, and both the existing and new
secondary clarifiers. The new RAS/WAS pumping station would be compatible with the
proposed configuration of aeration basins, and the rehabilitation of the existing secondary
clanfiers (and new clarifier to current technology standards. The opinion of probable cost
for the new RAS/WAS pumping station is $1,669,400.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 12
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DRAFT
1.6.6 Secondary Clarifier
A third secondary clanfier is required to meet maximum month average daily flow
conditions of greater than 18.0 MGD which are anticipated to occur within the next 5
years. The third secondary clarifier is also currently needed to meet reliability standards
of the Washington Department of Ecology to provide 'settlement for 75 percent of the
design flow with one unit off-line. Currently, the treatment capacity of one secondary
clarifier is calculated at 12.3 MGD. The opinion of probable cost for the new secondary
clarifier is $3,277,800. With the construction of the new secondary clarifier, the existing
secondary clanfiers would be refurbished to meet current technology standards.
Refurbishment of the existing secondary clarifiers is considered as a key feature project.
1.6.7 Aeration Basins
Construction of a future 2.1 million gallon aeration basin, and retrofit of the existing two
aeration basins of equivalent volume of 2.1 million gallons each, is recommended. An
anoxic selector basin would be constructed ahead of each aeration basin (existing and
future) for improved operation and control of the activated sludge process. For the new
influent and effluent flow split structure with anoxic selector cells for each basin, the
opinion of probable cost is $2,480,000. The opinion of probable cost for the future 2.1
million gallon aeration basin with anoxic selector cell and appurtenances is $4,366,600.
An additional blower would be added in the future with an opinion of probable cost of
$547,800.
1.6.8 Disinfection
Although maintaining the existing gaseous chlorine chlorination and gaseous sulfur
dioxide dechlorination systems provided the least costly alternative for disinfection of the
wastewater, the non -economic factors, such as potential safety risks to the operations staff
and the public, resulted in a recommendation to provide either low pressure or medium
pressure ultraviolet disinfection. The opinion of probable cost for the ultraviolet
disinfection system is $3,931,100.
1.6.9 Waste Activated Sludge
To provide for increased waste activated sludge flows in the future, and to provide an
effective long-term solution for waste activated sludge thickening redundancy, a pre -
manufactured rectangular dissolved air flotation thickener is recommended. The
thickener would be constructed concurrently to the expansion of the Solids Handling
Building. The opinion of probable cost for the rectangular dissolved air flotation
thickener and associated support equipment is $1,338,600.
1.6.10 Key Features
In addition to the major capital facility projects identified above, facility improvements
throughout the Yakima Regional Wastewater Treatment Plant were identified to include
safety, reliability, and improved process operation to maintain compliance with existing
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000 PAGE 13
DRAFT
state and federal regulations. Table 1-6 identifies these key feature projects with an
• opinion of probable cost.
•
Table 1-6. Wastewater Treatment Facility Key Features Projects
Facility Description
Opinion of
Probable Cost
Influent Building
Emergency Generator Overhaul (400 KW) /Replacement
Primary Clarifier Collector Mechanisms
Primary Sludge Pumping Density and Flow Meters
Primary Sludge Pumping Lighting Replacement
Sludge Transfer Building Refurbishment
Replace Intermediate Grit Box Center Wall
Trickling Filter Door/Walkway Covers
Trickling Filter Mechanism
Trickling Filter Clarifier Gates
Trickling Filter Clarifier Solids Removal System/Dewatering
Repair Existing Aeration Basin
Replace Blower VFD's
Aeration Basin Diffusers Rehab
Refurbish Secondary Clarifier Bull -Gears
Replace Secondary Clarifier Exterior Launders
Replace Secondary Clarifier Skimmer Mechanism/Scum Box
Refurbish DAFT Air Compressors/Pipelines
Replace Secondary Digester Recirculation Pumps
Install Secondary Digester Gas Flare
Trickling Filter Evaluation
Field Test Oxygen Transfer Efficiency
Secondary Clarifier Evaluation
Miscellaneous Improvements'
$50,000
$100,000
$400,000
$240,000
$10,000
$100,000
$250,000
$85,000
$782,500
$50,000
$425,000
$675,000
$490,000
$50,000
$120,000
$257,000
$362,000
$267,000
$203,000
$60,000
$50,000
$50,000
$50,000
$1,000,000
Total WWTP Opinion of Probable Costs
$6,126,500
'Five projects at $200,000 each. See Section 5 and 6.
The Tnckling Filter Evaluation, Field Test Oxygen Transfer Efficiency, and Secondary
Clarifier Evaluation projects are intended to establish service performance parameters for
these process areas of the Yakima Regional WWTP.
1.6.11 Resource Requirements
The proposed modifications and improvements set forth in Section 6 do not add new
process treatment systems at the Yakima Regional WWTP. The existing treatment
process systems will be increased in size to accommodate wastewater flows as population
increases throughout the service area. As new equipment and enlarged treatment process
systems are added, additional Operations staff and/or Maintenance staff may be required.
The Wastewater Division Manager should review the staffing requirements annually and
add staff as may be needed to maintain the current high level of operation and
maintenance of the Yakima Regional WWTP. Table 1-7 identifies the current annual
operations and maintenance staffing and costs for the Yakima Regional WWTP.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 14
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Table 1-7. Mandatory Yakima Regional WWTP Program Staffing O&M1
Category
Staffing/Equipment
Annual Cost
$375,000
$225,000
$1,650,000
$750,000
$600,000
$225,000
$420,000
$100,000
$1,592,000
$5,937,000
Program Administration
Engineering Support
Facility Operations/Biosolids
Facility Maintenance
Facility Laboratory
Food processing
Power/Water/Refuse/Chemicals
Machinery/Equipment
City Services/Ancillary Costs2
5 people/equipment
3 people/equipment
22 people/equipment
10 people/equipment
8 people/equipment
3 people/equipment
Total WWTP Staffing/Program
'Includes WWTP, Rudkin Road, Food Processing, and Laboratory
2Customer services, administrative overhead, state and local fees, debt service, and other charges.
The City of Yakima is mandated by WDOE through the NPDES permitting process to
accept responsibility for a fully delegated Pretreatment Program by July 2002. Over 125
permits will be required for existing institutional, commercial, and industrial facilities
now located within the City's service area. In addition to prepanng the permits,
reporting, and on-site inspections of each of the permitted facilities, the City will also be
responsible for sampling and testing each Significant Industnal Users discharge to the
collection system at least twice per year. The activities required for the fully delegated
Pretreatment Program are in addition to those responsibilities currently being performed
by City staff under the Strong Waste program. Table 1-8 identifies the expected
mandatory program staffing and costs for the combined Pretreatment Program and Strong
Waste Program. The initial program will require a minimum of 9 full-time equivalent
positions, to as many as 14 full-time equivalent positions, to meet the requirements of the
combined programs.
Table 1-8. City of Yakima Mandatory Pretreatment/Strong Waste Program
Cost
Category
Salary/Benefits
Operations
City Services/Ancillary Costs
Amortized Equipment Cost
Total
Annual Cost4
Annual Costs
$1,050,000
$40,000'
$218,0002
$78,0003
$1,386,000
$675,000
$25,000'
$140,0002
$50,0003
$890,000
1 Includes general office supplies, printing, postage, and annual public notices.
2. Customer services, administrative overhead, state and local fees, and other charges.
3 Vehicle expense, computers, and sampling equipment (5 -year replacement)
4 9 FTEs. (anticipated minimum staffing level in 2002)
5 14 FTEs. (anticipated maximum staffing level in 2002)
Additional laboratory space and staffing will be needed to meet the requirements of the
fully delegated Mandatory Pretreatment Program, and the increased requirements for
sampling and testing set forth in the NPDES permit. Other mandatory new programs
which may impact both laboratory space and staffing include handling of industnal
septage at the Yakima Regional WWTP, and the implementation of a Storm Water
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 15
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Management Program within the City of Yakima. Table 1-9 summarizes the staffing and
• laboratory space requirements for these mandatory added programs.
•
•
Table 1-9. City of Yakima Mandatory Laboratory Staffing Increase and
Laboratory Upgrades
Category
Fully Delegated
Pretreatment4
Industrial
Septage3
NPDES
Permits
Total
Operations
Personnel (FTE)
1.5
3 0
0.5
5 0
Personnel (Dollars)
$112,500
$225,000
$37,500
$375,000
Equipment/Chemicals
$25,000
$35,000
$10,000
$70,000
Total Annual Cost
$137,500
$260,000
$47,500
$445,000
Capital
Laboratory
$250,000
$200,000
$450,000
$800,0002
Expansion/Equipment
1 Mandatory under current NPDES permit.
2. Laboratory Expansion/Equipment Capital Costs of $800,000 includes fully delegated pretreatment program,
increased requirements of NPDES, and Industrial Septage program. With Storm Water Management, the
laboratory Expansion/Equipment Costs increase to $1,000,000 Storm Water will be Mandatory by 2003
3 Based on one hundred 1,000 gallon septage loads per month with testing for BOD, TSS, pH, metals, and
petroleum hydrocarbons. May not be considered Mandatory until 2005 or beyond.
4 Mandatory in 2002.
The current recommendation is to include the total cost of $1,000,000 for laboratory
expansion in the financial planning for the Yakima Regional WWTP. The decision on
selection of a preferred laboratory expansion would be postponed until the next update of
the Wastewater Facilities Plan.
1.7 Aeration Basin Structural Evaluation
Failing concrete within Aeration Basin No. 4 prompted a field structural evaluation to
investigate the basin floor/foundation concrete and subsurface conditions, with the intent
to determine the cause of the concrete failures. The field evaluation determined that the
observed cracks and voids within the basin concrete, at localized areas along the basin
north wall, are most likely caused by defects in the mixing and placing of the original
concrete wall footing. No significant signs of subgrade instability beneath either the
existing wall footings or the floor slab were observed.
The recommended repairs for the Aeration Basins included removal and replacement of
all deteriorated concrete, adding saw -cut expansion and contraction joints, and epoxy
coating of all basin walls. The opinion of probable cost for the Aeration Basin repairs
(including all 4 basins) is $675,000. This project has been listed as a key features project
in this report.
1.8 Gas Utilization and Cogeneration
An evaluation of current and future methane gas production was performed in Section 8.
A new boiler, operating on fuel oil with digester gas as a backup, was recommended.
Cogeneration was determined to be not cost-effective based on current cost of electncity,
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
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and the high amortization and operations and maintenance cost of the cogeneration
. generator. The opinion of probable cost for the new boiler and piping is $150,000.
•
•
1.9 Biosolids Management
Section 9 identifies the processing, handling, and utilization of biosolids produced from
the treatment of wastewater at the Yakima Regional WWTP. Regulations which guide
the biosolids utilization program are described, and recommendations were developed to
address the anticipated increase in biosolids quantity from a growing service area
population; to mitigate current operational issues; and to identify possible facility
enhancements to the biosolids utilization and reuse program.
The Yakima Regional WWTP has land applied biosolids in the Moxee area for 10 years.
The land application sites consist of several hop yards between 10 and 60 acres in size. In
several cases, the previous application of biosolids has increased available nitrogen in the
soil which does not allow further biosolids application. A larger application site under
City control/ownership will reduce soil sampling, monitoring, and testing costs of
multiple application sites, and allow higher application rates.
At the present time, the Yakima Regional WWTP produces a Class B biosolids product
which is compatible with the current agricultural land application program and has been
accepted by the local agricultural community. Alternatives to enhance the biosolids to
Class A to allow public use were considered including composting, chemical treatment,
and added digestion. While there may be some advantages to producing Class A
biosolids, the cost of producing Class A biosolids is high and there has been no
demonstrated desire for a Class A biosolids product in the Yakima region at this time:
1.9.1 Digester Capacity
Added digestion capacity will be required in the future to meet increased solids loading to
the Yakima Regional WWTP. Alternatives considered included single -stage mesophilic
anaerobic digestions (currently used), two-stage mesophilic anaerobic digestion,
temperature -phased anaerobic digestion, and pre -pasteurization followed by mesophilic
anaerobic digestion. Although both two-stage mesophilic anaerobic digestion, and
temperature -phased anaerobic digestion required less capital cost to construct than single -
stage mesophilic anaerobic -digestion, each process would require additional operator
attention. The current recommendation is to include the cost of single -stage mesophilic
anaerobic digestion in the financial planning for the facilities but postpone the decision
on selection of a preferred alternative until the next update of the Wastewater Facilities
Plan. The opinion of probable cost for the single -stage mesophilic anaerobic digester is
$4,000,000.
1.9.2 Secondary Handling of Centrate
Handling of centrate from the dewatering process is currently directed to the south storage
lagoon. The south lagoon is being considered as a possible storage area for food
processing wastewater. To mitigate the impact of the centrate ammonia load on the
HDR ENGINEERING, INC.
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SUMMARY - OCTOBER 25, 2000 PAGE 17
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activated sludge process, both equalization and biological treatment alternatives were
considered. A recommendation to biologically treat the centrate to nitrify the waste
stream is recommended. All discharge from the dewatering process to the lagoon would
be discontinued with this alternative. Future dredging and removal of solids from the
lagoon would not be required. The avoided annual cost of dredging and removal of solids
from the lagoon is estimated at $150,000 per year. The opinion of probable cost for this
alternate is $1,912,700.
1.9.3 Biosolids Dewatering/Drying Alternatives
Adequate redundancy for the existing high capacity centnfuge is needed. A second high
capacity centrifuge is recommended to meet future biosolids dewatering requirements and
resolve the redundancy issue. The opinion of probable cost for the new Centrifuge is
$1,589,100.
1.9.4 Polymer Addition Alternatives
To enhance the existing polymer feed system in the solids handling process and meet
future increased dewatenng requirements, a new dry polymer feed and storage system,
and a new liquid polymer feed and storage system, are recommended. The opinion of
probable cost for the new Polymer System is $976,200.
1.9.5 Solids Handling Building
The new dewatering equipment and polymer system, along with the need to fully enclose
the biosolids transport vehicles during loading, will necessitate the expansion of the
Solids Handling Building. The existing building would be expanded to the west, the
existing dewatering unit and a new dewatering unit would be installed in the upper floor
of the new addition above a new loadout facility. The new dry and liquid polymer feed
and storage systems, and a rectangular DAFT unit would be installed in the existing
solids handling building, and the existing solids laboratory would be expanded. The
opinion of probable cost for the expansion of the Solids Handling Building is $3,412,600.
1.9.6 Biosolids Utilization Alternatives
The direct hauling and utilization of biosolids to the land application sites, as currently
being performed by the Yakima Regional WWTP staff, is the least costly alternative for
the continued operation of the biosolids utilization program. To mitigate any potential
off-site air emissions which may result from the on-site storage of biosolids during
periods of inclement weather, providing off-site storage with provisions for on-site
enclosed storage is recommended. The purchasing or leasing of 2,000 acres of land for a
biosolids utilization site will provide the Yakima facility with better control and
reliability of the site. The opinion of probable cost for the enhanced Biosolids Utilization
program is $3,638,400. A new truck storage facility will be needed for biosolids
equipment with an opinion of probable cost of $400,000.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 18
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1.9.7 Resource Requirements
The level of effort required to properly administer the mandatory biosolids management
activities is extensive. Most, if not all, of the treatment plant on-site activities are part of
what is normally considered plant operations tasks. As the plant grows in size and new
processes are added, trained staff will be needed to maintain adequate operation of the
system. Assessment of operating staff size should be a regular part of planning and
budgeting. Depending on the range of options chosen, a staffing analysis should be
performed in conjunction with the design of these improvements.
1.10 Analysis of Existing Wastewater
Collection Facilities
Section 10 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 this 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. Table 1-10 identifies the proposed
budgeted operating expenses for the Collection System unit with a suggested 3 -year
implementation schedule beginning in 2002.
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CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
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Table 1-10. City of Yakima Proposed Collection System Expenses
W Description
Estimated
2001
Estimated
2002
Increase
01-02
Estimated
2003
Increase
02-03
Estimated
2004
Increase
03-04
Staff Costs
$1,115,950
$1,275,000'
$159,050
$1,425,0001
$150,000
$1,575,000'
$150,000
Operating Supplies,
Maintenance
$195,546
$223,000
$27,454
$249,000
$27,000
$276,000
$27,000
Machinery, and
Equipment
$293,363
$338,000
$44,637
$378,000
$40,000
$418,000
$40,000
City Services/Ancillary
Costs2
$600,570
$688,000
$87,430
$770,000
$82,000
$851,000
$82,000
Total
$2,205,429
$2,524,000
$318,571
$2,822,000
$298,000
$3,120,000
$298,000
•
•
12 FTEs added 2002, 2 FTEs added 2003, 2 FTEs added 2004.
2Customer services, administrative overheads, state and local fees, and other charges.
1.10.1 Stormwater Program
Although stormwater does not directly affect the wastewater facilities, the wastewater
utility is currently delegated with the responsibility of operating and maintaining the
City's storm sewer system on an on-call basis. Current annual expenses for stormwater
operations and maintenance paid by the wastewater utility are about $240,000 per year.
With the current emphasis on stormwater by the Environmental Protection Agency and
the Washington Department of Ecology, the City of Yakima will be mandated to develop
and implement a stormwater management program.
As described in the Comprehensive Storm Water Management Plan prepared for the City
of Yakima in 1995, the implementation of the Phase II EPA Storm Water Regulations
(adopted November 1, 1999) will require either a regional stormwater agency be
organized, or that each agency be responsible for implementation of their own stormwater
management program. A regional stormwater agency would be responsible for
management and implementation of common goals, and would likely reduce the
individual agency costs. Even with the support of a regional stormwater agency, the cost
of operation and maintenance of the City of Yakima stormwater utility will increase
significantly.
Table 1-11 provides a 5 -year implementation schedule for development of a mandatory
Environmental Protection Agency stormwater management program for the City of
Yakima without the support of a regional stormwater agency.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
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Table 1-11. Mandatory 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
$1,080,000
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
'Customer services, administrative overhead, state and local fees, and other charges.
The $3,380,000 annual costs includes $1,000,000 in capital amortization for projects
included in the City's Comprehensive Storm Water Management Plan ($3.7 million), and
enhancement projects which may be required to comply with the Endangered Species Act
($6.3 million). Even without ESA enhancement projects, the annual cost of operation
and maintenance of a stormwater management program would be over ten times greater
than anticipated expenditures in 2000 (2000 expenditures -$240,000; 2007 anticipated
expenditures without ESA -$2,750,000).
Alternative funding sources of stormwater operation and maintenance could include:
establishing a County wide utility for stormwater management; establishing an
independent City wide utility for stormwater management; or continued funding through
the wastewater utility by adopting a surcharge on the current wastewater service rate.
The Comprehensive Storm Water Management Plan recommended the development of a
regional stormwater agency. An initial rate of approximately $3.00 per month per
Equivalent Billing Unit (EBU) was suggested. Once the separate utility was in place, and
following the prioritization of government responsibilities and capital facility projects,
the rate would have been adjusted to meet the regional financial requirements. For the
City of Yakima, a $3.00 per month per EBU charge would produce an annual revenue of
approximately $1,100,000. Financing the $3,380,000 program identified in Table 1-11 in
2007 is anticipated to require a monthly EBU charge of $9.00.
1.11 Identification of Selected Wastewater
Collection Strategies
Section 11 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 interceptors within the Yakima Urban Reserve are described.
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SUMMARY - OCTOBER 25, 2000
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1.11.1 Existing System Deficiencies
The analysis of the existing collection system identified an opinion of probable cost of
$694,000 to correct existing system flow limitations to meet current conditions.
Correction of existing system deficiencies is mandatory to comply with the Four Party
Agreement.
1.11.2 Buildout System Deficiencies
The opinion of probable cost to meet system flow limitations for build -out within the
Yakima Urban Area was $1,867,000, or $1,173,000 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.
1.11.3 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
$27,111,900. 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 ($8,133,600) is 30 percent (15,000 people), and
the Yakima Urban Reserve area assignment of opinion of probable cost ($18,978,300) is
70 percent (35,000 people). Those costs attributed to providing system capacity to meet
population growth within the Yakima Urban Area is mandatory to comply with the Four
Party Agreement.
1.11.4 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 $9,475,000. The assignment of probable cost
to the Yakima Urban Area (30 percent) is $2,842,500 and the assignment to the Yakima
Urban Reserve area (70 percent) is $6,632,500. Again, system capacity attributed to
population growth within the Yakima Urban Area is mandatory to comply with the Four
Party Agreement.
1.11.5 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 $3,257,600.
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 a one-year in -system flow monitoring program to identify
HDR ENGINEERING, INC
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000 PAGE 22
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existing basin flows. The total opinion of probable costs for these two additional projects
. is $120,000 each, or $240,000.
•
•
1.12 Financial Planning/Implementation
In the development of this Mandatory Wastewater Facilities Plan, the capital facilities and
the requirements for annual operations and maintenance have been identified as either
Mandatory or Non -mandatory.
Mandatory capital facility improvements are those projects which add to the existing
wastewater facilities and are required to meet existing and new laws, rules, regulations,
and requirements of the federal and/or state government. There are currently no
constraints on the federal and/or state legislators, or the implementing agencies such as
EPA and WDOE, for the adoption of new laws, rules, regulations, and requirements.
Renewal, replacement, and health and safety capital improvements are mandatory in
maintaining cost-effective wastewater facility needs, and in complying with the existing
laws, rules, regulations, and requirements of the federal and/or state government. It is not
anticipated that the mandatory existing laws, rules, regulations, and requirements will be
relaxed in the future.
In addition to this mandatory requirement to comply with existing and new laws, rules,
regulations, and requirements of federal and state government, the City of Yakima was
delegated with the responsibility to provide for regional wastewater collection and
treatment of sewage within the Yakima Metropolitan area by WDOE in the mid 1970s.
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. The Four
Party Agreement created a mandatory obligation for the City of Yakima to offer regional
treatment plant and interceptor capacity to handle the sewage flows from and within an
Urban Service Boundary. The Urban Service Boundary was revised in 1982 to
correspond with the Yakima Urban Area Comprehensive Plan boundary as adopted by the
City of Yakima, Yakima County, and the City of Union Gap.
Mandatory compliance with federal and state laws, rules, regulations, and requirements
extends to the ongoing obligations of adequately staffing, operating, and maintaining the
facilities once they are constructed. Over the course of the past 50 to 60 years, dust like
new requirements for higher levels of treatment, new requirements for staffing, operation,
and maintenance have been adopted by the federal and state regulating agencies.
Municipal agencies, like the City of Yakima, have been required to comply, regardless of
ability to pay.
Non -mandatory capital facility improvements are those projects which are considered
discretionary. Such projects for the City of Yakima include expansion of the interceptor
sewers and the wastewater treatment plant to accommodate other Growth related
expansion occurring outside the boundaries as defined in the "Four Party Agreement".
Non -mandatory obligations of staffing, operation and maintenance would be associated
with the operations and maintenance of non -mandatory capital facilities.
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CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
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Recommended improvements/expansions to the wastewater facilities for the Yakima
Regional WWTP and for the City of Yakima Wastewater Collection System are
summarized in Section 12. Projects have been separated into the period into which the
improvements would be made (0-6 years; 7-12 years; and 13-20 years), and further
separated into two categories (Mandated by federal/state agencies to meet current and
future regulation; mandated to meet current and future health and safety regulations;
mandated to meet Growth related expansion of the service area by the Four Party
Agreement; and other Growth related expansion) for the Yakima Regional WWTP, and
two categories (Mandated to meet Growth related expansion of the service area by the
Four Party Agreement; and other Growth related expansion) for the collection/interceptor
sewer system. Other Growth related expansion is identified as those costs attributed to
population growth into the Yakima Urban Reserve area.
Table 1-12 identifies all improvements (treatment and collection) to be implemented
during the 0-6 year period.
Table 1-12. 0-6 Year Priority Improvement Projects
Improvement
Number
Facility Description
Opinion of
Probable Cost
Mandatory)
Regulations
Renewal/
Safety
Growth 2
FWWTP-2 ,
Emergency Generator Overhaul/Replacement
$100,000
$100,000
FWWTP-3
Primary Clarifier Collection Mechanisms (2 of 4)
$200,000
$200,000
FWWTP-4B
Primary Sludge Pumping Lighting Replacement
$10,000
$10,000
FWWTP-7A
Trickling Filter Door/Walkway Covers
$85,000
$85,000
FWWTP-7B
Trickling Filter Mechanism (1 of 2)
$391,300
$391,300
FWWTP-8A
Repair Existing Aeration Basin
$675,000
$675,000
FWWTP-8B
Replace Blower VFD's (2 of 4)
$245,000
$245,000
FWWTP-8C
Aeration Basin Diffusers Rehab
$50,000
$50,000
FWWTP-9A
Refurbish Secondary Clarifier Bull -Gears
$120,000
$120,000
FWWTP-9B
Replace Secondary Clarifier Exterior Launders
$257,000
$257,000
FWWTP-9C
Replace Secondary Clarifier Skimmer
$362,000
$362,000
Mechanism/Scum Box
FWWTP-10
Refurbish DAFT Air Compressors/Pipelines
$267,000
$267,000
FWWTP-12
Trickling Filter Evaluation
$50,000
$50,000
FWWTP-13
Field Test Oxygen Transfer Efficiency
$50,000
$50,000
FWWTP-14
Secondary Clarifier Evaluation
$50,000
$50,000
FWWTP-15
Miscellaneous Improvements
$200,000
$200,000
Subtotal FWWTP Improvements
$3,112,300
$1,120,000
$1,992,300
--
WWTP-2
Grit Storage Hopper
$100,000
$100,000
WWTP-5
New RAS/WAS Pumping Station
$1,669,400
$1,669,400
•
WWTP-6
New Secondary Clarifier
$3,277,800
$3,277,800
•
WWTP-13
Truck Storage
$400,000
$400,000
•
WWTP-16
Biosolids Handling
$3,638,400
$3,638,400
•
Subtotal WWTP Improvements
$9,085,600
$8,985,600
$100,000
--
TOTAL Treatment Plant Improvements
$12,197,900
$10,105,600
$2,092,300
--
Collection Model/Monitoring
Section 11
$240,000
$240,000
Collection Facility
Table 11-11
$694,000
$694,000
Collection Facility
Table 11-13 & 11-15
$1,173,000
$1,173,000
Collection Facility
Table 11-14 (20%)3
$5,422,400
$1,626,700
$3,795,700
Subtotal Collection Facility
$7,529,400
$1,866,700
$1,867,000
$3,795,700
TOTAL TREATMENT/COLLECTION
$19,727,300
$11,972,300 _
$3,959,300
$3,795,700
• Indicates benefits to Growth related issues.
'Compliance with federal/state laws and regulations, and the Four Party Agreement.
• 2Non-mandatory growth/system expansion.
330% to Mandatory, 70% to Growth
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CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
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Table 1-13 identifies all improvements (treatment and collection) to be implemented
during the 7-12 year period.
Table 1-13. 7-12 Year Priority Improvement Projects
Improvement
Number
Facility Description
Opinion of
Probable Cost
Mandatory'
Regulations
Renewal/
Safety
Growth'"
FWWTP-1
Influent Building
$50,000
$50,000
FWWTP-3
Primary Clarifier Collection Mechanisms (2 of 4)
$200,000
$200,000
FWWTP-5
Sludge Transfer Building Refurbishment
$100,000
$100,000
FWWTP-6
Replace Intermediate Grit Box Center Wall
$250,000
$250,000
FWWTP-7B
Trickling Filter Mechanism (1 of 2)
$391,200
$391,200
FWWTP-7D
Trickling Filter Clarifier Gates
$50,000
$50,000
FWWTP-8B
Replace Blower VFD's (2 of 4)
$245,000
$245,000
FWWTP-11B
Install Secondary Digester Gas Flare
$60,000
$60,000
FWWTP-15
Miscellaneous Improvements
$400,000
$200,000
$200,000
Subtotal FWWTP Improvements
$1,746,200
$200,000
$1,546,200
--
WWTP-2
Grit Storage Hopper
$212,100
$212,100
WWTP-4A
Trickling Filter Media Replacement
$1,699,100
$1,699,100
•
WWTP-4B
Trickling Filter Forced Ventilation
$1,066,100
$1,066,100
•
WWTP-7A
Anoxic Selector Cells
$2,480,000
$2,480,000
WWTP-7B
Aeration Basin (2.1 mg)
$4,366,600
$4,366,600
WWTP-8
UV Disinfection
$3,931,100
$3,931,100
•
WWTP-9
WAS Thickening
$1,338,600
$1,338,600
•
WWTP-10
Centrate Pretreatment
$1,912,700
$1,912,700
•
WWTP-11A
Solids Building
$3,412,600
$3,412,600
•
WWTP-11B
New Centrifuge
$1,589,100
$1,589,100
•
WWTP-11C
Polymer System
$976,200
$976,200
•
WWTP-12
Laboratory Modifications
$1,000,000
$1,000,000
•
WWTP-14
New Boiler/hot water
$150,000
$150,000
•
I,ubtotal WWTP Improvements
$24,134,200
$16,640,300
$3,127,300
$4,366,600
TOTAL Treatment Plant Improvements
$25,880,400
$16,840,300
$4,673,500
$4,366,600
Collection Facility
Table 11-15 (inc only)3
$7,608,000
$2,282,400
$5,325,600
Maintenance Bldg
Section 11
$3,257,600
$2,606,100
$651,500
Collection Facility
Table 11-14 (40%)3
$10,844,800
$3,253,400
$7,591,400
Subtotal Collection Facility
$21,710,400
$8,141,900
$13,568,500
TOTAL TREATMENT/COLLECTION
$47,590,800
$24,982,200
$4,673,500
$17,935,100
•
• Indicates benefits to Growth related issues.
'Compliance with federal/state laws and regulations, and the Four Party Agreement.
2Non-mandatory growth/system expansion.
330% to Mandatory, 70% to Growth
Table 1-14 identifies all improvements (treatment and collection) to be implemented
during the 13-20 year period.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
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Table 1-14. 13-20 Year Priority Improvement Projects
' Improvement
Number
Facility Description
Opinion of
Probable Cost
Mandatory'
Growth 2
Regulations
Renewal/
Safety
FWWTP-4A
Primary Sludge Pumping Density and Flow
$240,000
$240,000
Meters
FWWTP-7D
Trickling Filter Clarifier Solids Removal
$425,000
$425,000
System/Dewatering
FWWTP-11A
Add Secondary Digester Recirculation Pumps
$203,000
$203,000
FWWTP-15
Miscellaneous Improvements
$400,000
$400,000
Subtotal FWWTP Improvements
$1,268,000
$1,268,000
WWTP-1
Septage Receiving Facility
$2,079,300
$2,079,300
WWTP-3
Primary Split Box
$870,500
$870,500
•
WWTP-7C
Additional Blower
$547,800
$547,800
WWTP-15
Mesophilic Digestion
$4,000,000
$4,000,000
Subtotal WWTP Improvements
$7,497,600
$2,079,300
$870,500
$4,547,800
TOTAL Treatment Plant Improvements
$8,765,600
$2,079,300
$2,138,500
$4,547,800
Collection Facility Table 11-14 (40%)3
$10,844,700
$3,253,400
$7,591,300
Subtotal Collection Facility
$10,844,700
$3,253,400
$7,591,300
TOTAL TREATMENT/COLLECTION
$19,610,300
$5,332,700
$2,138,500
$12,139,100
• Indicates benefits to Growth related issues.
'Compliance with federal/state laws and regulations, and the Four Party Agreement.
2Non-mandatory growth/system expansion.
330% to Mandatory, 70% to Growth
Table 1-15 summarizes the total opinion of probable cost for wastewater treatment plant
and collection system costs over the next 20 years by the time period for which they are
anticipated to occur.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 26
•
•
itAFT
TABLE 1-15. SUMMARY OF IMPROVEMENTS
TREATMENT/
COLLECTION
OPINION OF
PROBABLE
COST
MANDATORY1
%
MANDATORY
-
a
GROWTH
.TOTAL "%
GROWTH
REGULATIONS
RENEWAL/SAFETY
Wastewater Treatment
- -
0-6 Year Projects3
$12,197,900
$10,105,600
$2,092,300
"100.0
----
0.0
7-12 Year Projects
$25,880,400
$16,840,300
$4,673,500
, 83.1 --
$4,366,600
16:9
13-20 Year Projects
$8,765,600
$2,079,300
$2,138,500
48.1 -
$4,547,800
; 51:9
Total Treatment Plant
Improvements
$46,843,900
$29,025,200
$8,904,300
81.0
$8,914,400
-' .19.0
Collection Facility
0-6 Year Projects3
$7,529,400
$1,866,700
$1,867,000
49:6
$3,795,700
50.4'-
7-12 Year Projects
$21,710,400
$8,141,900
----
373.
$13,568,500
;62.5
13-20 Year projects
$10,844,700
$3,253,400
----
30:0
$7,591,300
"70.0
Total Collection
Facility Improvements
$40,084,500
$13,262,000
$1,867,000
37.7 '
$24,955,500
62.3
TOTAL
TREATMENT/
$86,928,400
$42,287,200
$10,771,300
61.0
$33,869,900
39.0
COLLECTION
Mandatory compliance with federal/state laws and regulations, and the Four Party Agreement. Non -mandatory growth/system expansion receives a benefit from mandatory projects.
2Non-mandatory growth/system expansion.
3For the 0-6 Year period, a total of $19,727,300 is required. $15,931,600, or 80.8 percent, is required to meet mandatory obligations. $3,795,700, or 19.2 percent, is required to meet
non -mandatory growth/system expansion.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 27
DRAFT
During the next 6 years, the Yakima Regional WWTP must invest $12,197,900 in the
treatment facilities, 100 percent of which is required to meet mandatory regulatory
requirements, to maintain existing facilities, and to provide for mandatory system
expansion within the Service Area. Also during the next 6 years, the City of Yakima and
the development community must invest $7,529,400, 49.6 percent of which is required to
meet mandatory requirements, in extension of new interceptor and trunk sewers into
currently unsewered areas, and in replacement and/or parallel interceptor and trunk
sewers to accommodate the expanded Service Area.
Over the 20 -year period, the Yakima Regional WWTP must invest $46,843,900 in the
treatment facilities to meet mandatory regulatory requirements, to maintain existing
facilities, and to provide mandatory and non -mandatory system expansion for growth
within the Service Area. Dunng this same period, the City of Yakima and the
development community must invest $40,084,500 in extension of new interceptors and
trunk sewers into currently unsewered areas, and in replacement and/or parallel
interceptor and trunk sewers to accommodate the expanded Service Area. Also during
this period, the development community and individual home owners will invest
approximately $80,000,000 to $100,000,000 in construction of collection system
pipelines of 10 -inches in diameter or less.
Of the total $86,928,400 in capital expenditures identified in this Mandatory Wastewater
Facilities Plan for wastewater treatment and collection system improvements,
$53,058,500 of these improvements are required to meet Mandatory laws and regulations
of state and federal agencies (both existing and future); Mandatory requirements for
compliance with NPDES permit conditions (renewal and renovation); and Mandatory
obligations to provide regional wastewater treatment and interceptor sewers to the
Yakima Area as defined in the "Four Party Agreement".
The remaining $33,869,900 in capital expenditures identified in the Mandatory
Wastewater Facilities Plan are for those improvements directly resulting from an increase
in the service area and an increase in the population to be served.
For those Mandatory Projects which result in benefits to Growth as indicated in Table 1-
12, 1-13, and 1-14, that portion of the total opinion of probable cost benefiting other
Growth has been identified in Table 1-16.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 28
DRAFT
Table 1-16. Assignment of Probable Cost to Growth of the Service Area
Improvement
Number
Facility Description
Opinion of
Probable Cost
Mandatory
Growth
WWTP-3
Primary Split Box3
$870,500
$435,250
$435,250
WWTP-4A
Trickling Filter Media Replacement2
$1,699,100
$339,820
$1,359,280
WWTP-4B
Trickling Filter Forced Ventilation2
$1,066,100
$213,220
$852,880
WWTP-5
New RAS/WAS Pumping Station'
$1,669,400
$834,700
$834,700
WWTP-6
New Secondary Clarifier'
$3,277,800
$1,638,900
$1,638,900
WWTP-8
UV Disinfection2
$3,931,100
$3,144,880
$786,220
WWTP-9
WAS Thickening2
$1,338,600
$669,300
$669,300
WWTP-10
Centrate Pretreatment2
$1,912,700
$956,350
$956,350
WWTP-1 IA
Solids Building2
$3,412,600
$2,047,560
$1,365,040
WA/TP-11B
NewCentrifuge2
$1,589,100
$794,550
$794,550
WWTP-11C
Polymer System2
$976,200
$488,100
$488,100
WWTP-12
Laboratory Modifications2
$1,000,000
$700,000
$300,000
WWTP-13
Truck Storage'
$400,000
$100,000
$300,000
WWTP-14
New Boiler/hot water2
$150,000
$50,000
$100,000
WWTP-16
Biosolids Handling'
$3,638,400
$2,910,720
$727,680
TOTAL Assignment of Improvements
$26,931,600
$15,323,350
$11,608,250
0 6 Year Pnonty Improvements (Table 1-12)
27-12 Year Priority Improvements (Table 1-13)
313-20 Year priority Improvements (Table 1-14)
As identified in Table 1-16, in meeting the Mandatory requirements for the Yakima Area,
$11,608,250 in capital expenditures out of to total $26,931,600 will result in benefits to
the increased service area and increased population. A total of $3,501,280 in capital
expenditures of the total $12,197,900 in treatment plant improvements identified in Table
1-12 provide benefits to the increased service area and increased population.
Table 1-17 allocates the total opinion of probable cost for wastewater treatment plant and
collection system costs over the next 20 years by Mandatory and Non -mandatory
growth/system expansion.
Table 1-17. Improvements by Mandatory and Non -mandatory Allocation
Treatment/Collection
Opinion of
Probable Cost
Mandatory
Non -mandatory
Wastewater Treatment
0-6 Year Projects
$12,197,900
$8,696,620
$3,501,280
7-12 Year Projects
$25,880,400
$13,842,080
$12,038,320
13-20 Year Projects
$8,765,600
$3,782,550
$4,983,050
Total Treatment Plant
Improvements
$46,843,900
$26,321,250
$20,522,650
Collection Facility
0-6 Year Projects
$7,529,400
$3,733,700
$3,795,700
7-12 Year Projects
$21,710,400
$8,141,900
$13,568,500
13-20 Year Projects
$10,844,700
$3,253,400
$7,591,300
Total Collection Facility
Improvements
$40,084,500
$15,129,000
$24,955,500
TOTAL
TREATMENT/COLLECTION
$86,928,400
$41,450,250
$45,478,150
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 29
DRAFT
Financial options available to the City of Yakima for financing both mandatory and non-
mandatory obligations for expansion and continued operations of the interceptors and
treatment facilities are currently being developed in a Cost -of -Service Study. The Cost -
of -Service Study will include capital costs, annual operations and maintenance expenses
and staffing obligations.
Compliance with federal and/or state mandatory regulations requires adequate funding
sources, regardless of ability to pay. Although the federal and/or state regulatory agencies
sometimes provide partial funding for mandated improvements in the form of grants and
loans, those resources have been diminished dramatically over the last decade. As a
consequence, the City of Yakima and the Yakima Regional WWTP will be required to
use wholesale and retail revenues to pay a substantial portion (90 percent or more) of the
total costs either as cash or debt payments. The impact to wholesale and retail rates will
be significant.
Present City policy allows funding for mandatory renewals and replacements from
wholesale/retail revenues. As a general financial "rule of thumb" the City of Yakima
should be funding mandatory renewals and replacements from rates at an amount greater
than the annual depreciation expense. Annual depreciation expense reflects the current
investment in the Yakima Regional WWTP and collection system that is being
depreciated. The wastewater treatment plant investment needs to be replaced in order to
maintain the existing level of infrastructure. The 1999 annual depreciation expense for
the Yakima Sewer Utility was approximately $2.9 M. Simply funding the annual
depreciation expense will not generate sufficient revenues to replace the existing or
depreciated facility.
Growth related facilities are generally funded with new financial resources generated
from property assessments, connection charges, and development fees. Federal and/or
state funding sources are often limited for new construction for growth related facilities.
If available, funding sources are generally limited to replacement of existing
infrastructure, promotion of economic growth of the community, or for resolving a health
threat in the area to be served.
HDR ENGINEERING, INC.
CITY OF YAKIMA
SUMMARY - OCTOBER 25, 2000
PAGE 30
•
DRAFT
City of Yakima
Mandatory Wastewater Facilities Plan
SECTION 2
Waste Discharge and Treatment
Requirements
• October 2000
prepared by
Tim Hunter/Dan Harmon
HDR Engineering, Inc.
•
reviewed by
John Koch
Tony Krutsch
City of Yakima
•
•
DRAFT
Table of Contents
2.1 Introduction 1
2.1.1 Surface Water Quality Standards - Beneficial Uses 5
2.1.2 Surface Water Quality Standards - Criteria 5
2.2 Nutrient Removal 10
2.2.1 Phosphorus 10
2.2.2 Nitrogen 10
2.3 Biomonitoring and Whole Effluent Toxicity Testing 11
2.4 Infiltration and Inflow Control 12
2.5 Groundwater Protection and Impacts on Unsewered Areas 12
2.5.1 General Groundwater Quality and Protection 13
2.5.2 Regulation of Septage Disposal 13
2.6 Biosolids Management 15
2.6.1 Washington Regulatory Guidance 16
2.7 Land Application of Treated Wastewater 16
2.7.1 Washington Regulatory Review 17
2.7.2 Water Reuse 19
2.8 Wetlands for Wastewater Treatment 20
2.9 Land Application of Food Processing Waste 20
2.10 Endangered Species 20
2.10.1 Washington Salmon Recovery 23
2.11 Pretreatment 24
2.12 Air Pollution 27
2.12.1 The Clean Air Act and Rules for the Control of Air Pollution in
Washington 27
2.12.2 Clean Air Act Risk Management Plans 29
2.12.3 Chorine -specific Regulations 29
2.13 Virus Control 31
2.14 Noise 31
2.15 Stormwater 31
HDR ENGINEERING, INC.
CITY OF YAKIMA
WASTE DISCHARGE AND TREATMENT REQUIREMENTS, October 6, 2000
Page i
•
•
t
City of Yakima
SECTION 2
Waste 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 permitting requirements considered
is the National Pollutant Discharge Elimination System (NPDES) permit, which governs
effluent discharged from the Yakima Regional Wastewater Treatment Plant to the
Yakima River.
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 Environmental Protection Agency (EPA) 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 effect the future of the wastewater utility.
The Yakima Regional WWTP currently operates under NPDES permit number WA -
002402 -3, issued September 8, 1997. The permit will expire on June 30, 2002. A copy
of the NPDEs Permit and the WDOE worksheet prepared in development of the permit
are 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); 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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
WASTE DISCHARGE AND TREATMENT REQUIREMENTS, October 6, 2000
Page I
•
•
a!,
Table 2-1. Summary of Anticipated Regulatory and Permitting Issues
Regulatory
Issue/Parameter
Issues and Current Status
NPDES Permit
Limits'
Importance to
Planning
Effluent Discharge
WWTP Flow
BOD and TSS
Phosphorus
Total Nitrogen
Ammonia Nitrogen
Chlorine Residual
Bacteria
Metals
Biomonitoring
Infiltration/Inflow
Biosolids
Virus Control
Wastewater Treatment Facility permitted flow (22.3 mgd, daily average — max. month).
Secondary treatment standards (30/30 and 85% removal).
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 the 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/1 monthly ave., 0 029 mg/1 daily max).
Fecal coliform limits (200/400 organisms per 100 mis) (May be modified to e -coli in future).
Elevated levels of Silver, Mercury, Copper, and Lead in upper river from historic mining activity
BMPs required for local commercial/industrial sources. Metals are of high importance under
pretreatment program.
Whole effluent toxicity testing required for acute and chronic toxicity
Collection system rehabilitation projects have reduced I&I. Infiltration is related to seasonal use
of irrigation system in the community
Biosolids management must meet 40 CRF 503; biosolids standards.
May have stricter requirements in the future as analytical methods improve.
HDR ENGINEERING, INC.
CITY OF YAKIMA
WASTE DISCHARGE AND TREATMENT REQUIREMENTS, October 6, 2000
Y
C,M
N
N
C
C
C
N
Y
S
S
N
High
Moderate
Moderate
Moderate
High
High
High
Moderate
High
High
Moderate
Moderate
Page 2
• • all,
Regulatory
Issue/Parameter
Issues and Current Status
NPDES Permit
Limits
Importance to
Planning
Effluent
TMDL and Watershed
Planning
Chlorine Byproducts
Effluent Reclamation and
Reuse
Treatment Plant
Air Emissions
Air Toxics
Air Contaminants
Visual Appearance
Noise Control
Sprayfield Discharge
Sprayfield Flow
BOD and TSS
Bacteria
TKN
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.
W,DOE Land Application Guidelines apply to reclamation and reuse. Effluent reuse may be a
management tool for Toad diversion from the Yakima River
Regulations apply to VOCs, H2S, C12, but not likely to be considered major source.
Clean Air Act Section 112r Risk Management Plan (RMP) requirements had compliance deadline
of June 21, 1999 New regulations proposed by EPA on Urban air toxics may become an issue in
the future.
Yakima County Clean Air Authority potential Title V Permit. Model run indicated 609 lbs. of
pollutants discharged into the air. This is below the permitting threshold.
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.
Maintenance of good neighbor policy has high priority City of Yakima regulatory requirements
apply
Food Processing Waste Sprayfield permitted flow (0.75 mgd).
TBD2
Total Coliform Limit TBD2
TBD2
HDR ENGINEERING, INC.
CITY OF YAKIMA
WASTE DISCHARGE AND TREATMENT REQUIREMENTS, October 6, 2000
N
N
N
N
Moderate
Moderate
Moderate
Low
High
Low
High
High
High
High
High
High
Page 3
•
•
al.
Regulatory
Issue/Parameter
Issues and Current Status
NPDES Permit
Limits'
Importance to
Planning
PH
TBD2
N
High
Land Application
Future Limits for the application of food processing waste at the Sprayfield will be determined by
S
High
WDOE2 Setbacks, fencing and compatibility with greenway trails are issues of concern.
Endangered Species Act
Salmon
Legislation relating to salmon recovery in Washington has the potential to significantly impact
wastewater discharges, water conservation, and management of instream flows.
N
Moderate
Other
Other ESA listings in Yakima County are identified in the text.
N
Low
Pretreatment
The Yakima Regional WWTP Pretreatment program is currently a "Partial Pretreatment Program".
Y
High
The City is required to apply for full delegation prior to the next permit cycle which begins June
30, 2002.
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 program has potential designations for small urban areas with
populations of 10,000 or more with permits required by February, 2003. Regulated small
municipal separate storm sewer systems are to have programs developed and implemented by
Y
High
2008. Stormwater loadings to the Yakima River consume shared assimilative capacity. Inflow
reduction efforts to reduce peak wastewater loadings may increase stormwater loadings and
infrastructure requirements.
2
Anticipated content of renewed NPDES discharge permit, coded as follows:
Y, Yes included
N, No, not included
C, Concentration Limit
M, Mass Limit
S, Supplementary Condition
TBD means " to be determined" by the Washington State Department of Ecology prior to the expiration date of the permit, and based on the Sprayfield Engineering Report
(condition S 1 1 of the permit). The limits may be set by Administrative Order
HDR ENGINEERING, INC.
CITY OF YAKIMA
WASTE DISCHARGE AND TREATMENT REQUIREMENTS, October 6, 2000
Page 4
DRAFT
2.1.1 Surface Water Quality Standards - Beneficial Uses
The Yakima River flows east and south from Lake Keechelus through the Kittitas Valley,
then cuts a deep canyon through the Manastash and Umantum 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 is designated
as a Class A receiving water (Table 2-2) 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. Problems include sediments, nutrients, pesticides, turbidity,
metals, and bacterial contamination.
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.
The segment of the Yakima River that receives the plant discharge is on WDOE's 303(d)
list because of violations of water quality standards for Fecal Coliform Bacteria, DDT, 4-
4' -DDE, Dieldrin, and pH. 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. 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.
2.1.2 Surface Water Quality Standards - Criteria
Allowable concentrations of chemical pollutants in surface water are based on the water
quality standards necessary to protect the beneficial uses of natural water sources.
Applicable criteria are defined in WAC 173-201A for aquatic biota. In addition, EPA has
promulgated human health critena for toxic pollutants under the National Toxics Rule.
Surface water quality -based limits are derived for the waterbody's "critical" conditions,
which represents the receiving water and wastewater discharge conditions with the
highest potential for adverse impact on the aquatic biota, human health, and existing or
charactenstic water body uses. Criteria for the Yakima River are summarized in
Table 2-2.
HDR ENGINEERING, INC.
CITY OF YAKIMA
WASTE DISCHARGE AND TREATMENT REQUIREMENTS, October 6, 2000
Page 5
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DRAFT
Table 2-2. Class A (excellent) and Class B (good) characteristic uses,
freshwater quality criteria, and special conditions for the lower Yakima
River and tributaries (WAC 173-201A)
Class A
Class B
General Characteristics.
Characteristic Uses.
Water Quality Criteria:
Fecal Coliform
Dissolved Oxygen
Total Dissolved Gas
Temperature (Special
Yakima River only)
Temperature
pH
Turbidity
Shall meet or exceed the requirements for
all or substantially all uses.
Shall include, but not be limited to the
following: Water Supply (domestic,
industrial, agricultural); Stock Watering;
Fish and Shellfish, Salmonoid and other
fish migration, rearing, spawning, and
harvesting. Crustaceans and other shellfish
rearing, spawning, and harvesting; Wildlife
Habitat; Recreation (primary contact, sport
fishing, boating, and aesthetic enjoyment);
Commerce and Navigation.
Shall both not exceed a geometric mean
value of 100 colonies/100 mL, and not
have more than 10% of all samples
obtained for calculating the geometric
mean exceeding 200 colonies/100 mL.
Shall not exceed 8 mg/L.
Shall not exceed 110% of saturation of any
point of sample collection.
Condition for lower Shall not exceed 21 0 degC due to human
activities. When natural conditions exceed
21 degC, no increase allowed which raises
receiving water temperature greater than
0.3 degC; nor increases at any time shall
exceed t=34/(T+9).
Shall not exceed 18.0 degC due to human
activities. When natural conditions exceed
18 degC, no increase allowed which raises
receiving water temperature greater than
0.3 degC; nor increases at any time shall
exceed t=28/(t+7)
Shall be within the range of 6.5 to 8.5 with
a human -caused variation within a range of
less than 0.5 units.
Shall not exceed 5 NTU over background
when the turbidity is 50 NTU or Less, or
have more than a 10% turbidity increase
when background is more than 50 NTU
Concentrations shall be below those which
have the potential either singularly or
cumulatively to adversely affect
characteristic water uses, cause acute or
chronic conditions to the most sensitive
biota dependent upon those waters, or
adversely affect public health as
determined by the department.
Shall not be impaired by the presence of
materials or their effects, excluding those
of natural origin, which offend the senses
of sight, smell, touch, or taste.
Toxic, radioactive, or deleterious materials
Aesthetic Values
Shall meet or exceed requirements for most
uses.
Shall include, but not be limited to the
following: Water Supply (industrial,
agricultural); Stock Watering; Fish and
Shellfish, Salmonoid migration, rearing,
spawning, and harvesting. Other fish,
Crustaceans and other shellfish rearing,
spawning, and harvesting; Wildlife Habitat;
Recreation (secondary contact, sport fishing,
boating, and aesthetic enjoyment);
Commerce and Navigation.
Shall both not exceed a geometric mean
value of 200 colonies/100 mL, and not have
more than 10% of all samples obtained for
calculating the geometric mean exceeding
400 colonies/100 mL.
Shall exceed 6.5 mg/L.
Same as Class A.
Same as Yakima River Special Condition.
Same as Class A
Same as Class A.
Shall not exceed 10 NTU over background
when the turbidity is 50 NTU or less, or have
more than a 20% turbidity increase when
background is more than 50 NTU
Same as Class A.
Shall not be reduced by dissolved,
suspended, floating, or submerged matter not
attributed to natural causes, so as to affect
water use or taint the flesh of edible species.
HDR ENGINEERING, INC.
CITY OF YAKIMA
WASTE DISCHARGE AND TREATMENT REQUIREMENTS, October 6, 2000
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2.1.2.1 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 cnteria 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 critena
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. A proposed revision to WAC 173-201A is anticipated in June 2000.
2.1.2.2 Criteria
The general surface water quality cnteria 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. "Numencal" 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 primanly
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 matenal 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
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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 nsk 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.
2.1.2.3 Mixing Zones
The Surface Water Quality Standards allow WDOE, in establishing water quality -based
effluent limits around a point of discharge, to authorize mixing zones for only those
discharges that are receiving "All Known, Available, and Reasonable methods of
prevention, control, and Treatment" (AKART), and which are also in accordance with the
other applicable mixing zone requirements (i.e. geometric configuration, flow restriction)
of WAC 173-201A-100. Both acute and chronic mixing zones may be authorized for
pollutants that can have a toxic effect on the aquatic environment near the point of
discharge. The concentration of pollutants at the boundary of these mixing zones may not
exceed the "numerical" criteria for that type of zone. HDR Engineering, Inc., in the
March 11, 1993 Effluent Mixing Zone Study Report, calculated the dilution factors for
both the acute and chronic mixing zones at varying receiving water flows. The acute and
chronic dilution factors found at the actual study flow of 860 cfs were 5 and 14,
respectively. The acute and chronic dilution factors calculated by the engineering report
at the lowest -flow of 1,000 cfs were 6 and 16, respectively. All of the dilution factors
calculated by the engineering report incorporated the WDOE requirements as contained
in WAC 173-201A-100, wherein only 25 percent (chronic) and 2.5 percent (acute) of the
receiving water flow can be used in calculating the dilution factors.
The WDOE's Environmental Investigations and Laboratory Services Program (ELLS) has
determined the 7Q10 (lowest seven-day average river flow with a recurrence interval of
ten years) of the Yakima River (USGS 12500405) is 632 cfs based on flow monitoring
data for the period of record 1968 to 1995. WDOE used this calculated 7Q10 value, in
conjunction with subsequent velocity data provided in a May 27, 1997 letter from HDR
Engineering Inc., for determining that the proposed permit's acute and chronic mixing
zone dilution factors should be 1.51 and 6.61 respectively (using the RIVPLUME5
computer model). The acute dilution factor was limited by 2.5 percent of the 7Q10 flow
(15.8 cfs) of the Yakima River, and the chronic dilution factor was limited by 25 percent
of the 7Q10 flow (158 cfs) of the Yakima River as determined by WDOE.
The National Toxics Rule typically allows chronic mixing zones, different from that
calculated for aquatic life, to be used to meet the separate criteria for human health. This
includes both carcinogenic and non -carcinogenic toxic pollutants. Data from the same
period of record as the 7Q10 were utilized in determining the other applicable receiving
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water flows and velocities for calculation of the final effluent dilution factors for human
health.
Table 2-3, below, indicates all of the pertinent receiving water data used for calculating
both aquatic life -based, and human health -based, dilution factors.
Table 2-3. Flows Used in Determining Effluent Limits on River Discharge'
Parameter Acute Aquatic Life- Chronic Aquatic Human Health Human Health Non -
Based Limits Life -Based Limits Carcinogenic Limits Carcinogenic Limits
POTW Effluent
Flows
Highest Actual Daily
Maximum Flow During
the Past 3 Years = 30 775
cfs
Yakima River 7Q10 Flow and Velocity =
Flows 632 cfs and 3.07 fps
Highest Actual
Monthly Average
Flow During the Past
3 Years = 28.145 cfs
7Q10 Flow and
Velocity = 632 cfs and
3.07 fps
Average Annual
Design Flow = 21.198
cfs
Harmonic Mean Flow
and Velocity = 2320
cfs and 4 05 fps
Highest Actual Monthly
Average Flow During the
Past 3 Years = 28.145 cfs
30Q5 Flow and Velocity
= 920 cfs and 3 60 fps
Calculated 1.51 6.61 10.27 7.33
Dilution Factors
'Based on POTW flow records prior to 1997.
2.1.2.4 NPDES Permits
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 National Pollutant Discharge Elimination System
(NPDES) permit program, which is administered by the United States Environmental
Protection Agency (EPA). The EPA 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 the Washington Department of Ecology's (WDOE) authonty and
obligations in administering the wastewater discharge permit program.
The regulations adopted by WDOE include procedures for issuing permits (WAC 173-
220), technical criteria for discharges from municipal wastewater treatment facilities
(WAC 173-221), and water quality criteria for surface and ground waters (WAC 173-
201A and WAC 173-200). These regulations require that a permit be issued before
discharge of wastewater to waters of the State is allowed. The regulations also establish
the basis for effluent limitations and other requirements which are to be included in the
permit.
The existing permit for the Yakima Regional WWTP authonzes the discharge of treated
wastewater to the Yakima River from two outfalls. Outfall No. 001 is the discharge from
the wastewater treatment facility. The permit for this outfall includes limits for BOD5,
TSS, fecal coliform, pH, total ammonia, and total residual chlorine. Outfall No. 002 is
the Food Processing Waste Sprayfield. An interim limitation has been placed in the
permit for this outfall with regard to flow. Future limits for flow, BOD5, TSS, total
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coliform bacteria, TKN, and pH will be determined by the State prior to the expiration
date of the current discharge permit (June 30, 2002). The final limitations, which are to
be determined, go into effect on July 1, 2001.
In addition to the current effluent limitations, the future may bring new or more stringent
requirements. Based on discussion with WDOE, the aspects most likely to affect the
Yakima discharges are the loadings of nutrients (nitrogen and particularly phosphorus),
and toxics; including metals, ammonia, and chlorine. Nutnent removal will be described
in the following section. WDOE has indicated that municipal dischargers will not be the
focus of permitting and enforcement activities in the near term (up to 15 years), as the
majority of water quality issues in the area are associated with agricultural activity and
non -point source discharges.
2.2 Nutrient Removal
2.2.1 Phosphorus
Nutrients are natural components of every aquatic system. The inherent fertility of a
stream, measured as the concentration of nitrogen, phosphorus, and other nutrients, is an
important factor in fish production, and often controls the amounts of algae a river or lake
produces. When a waterbody becomes overloaded with nutrients, from natural or man-
made sources, nuisance growths of algae may result. In extreme cases, large
concentrations of algae can deplete the dissolved oxygen needed by fish, and otherwise
impact beneficial uses of the waterbody. In pristine waters, nitrogen or phosphorus are
present in amounts that are low enough to prevent nuisance algae growth. As nutrient
concentrations increase, nitrogen or phosphorus become "limiting factors" in the
development of nuisance growths. This means that the addition of relatively small
quantities of the limiting nutrients could result in substantial increases in algae growth. It
may become necessary to control phosphorus discharges through the use of water quality
management tools such as TMDLs in the future. A TMDL would allocate a load and/or
concentration of phosphorus that could be discharged by the Yakima Regional WWTP.
These limitations would become an enforceable part of the NPDES discharge permit.
Phosphorus limitations in the discharge permit are likely, but will probably not occur,
within the next two permit cycles (10 years).
2.2.2 Nitrogen
Nitrogen concentrations in natural surface water bodies : can also lead to water quality
problems, particularly _due to the -toxicity of ammonia to aquatic biota and the role of
nitrogen in algae proliferation. Ammonia toxicity has been addressed through an NPDES
permit limitation in Yakima's permit. Water quality problems relating to nutrient
enrichment could prompt total nitrogen limits for wastewater treatment plant effluent
discharge. In anticipation of such changes, other treatment plants in the region are
currently looking toward nitrogen removal processes, though the permits do not
necessarily require such measures.
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A commonly used method for ammonia removal is to utilize the organisms in the
biological treatment process to perform nitrification, which is the conversion of
ammonia -nitrogen to nitrate -nitrogen. Nitrification is currently achieved at the Yakima
Regional WWTP to meet the average monthly NPDES permit limit of 4.16 mg/L NH4-N.
In order to more completely remove nitrogen from the treatment plant effluent, a
subsequent step in the biological process, called denitrification can be added. The
denitrification process involves the release of nitrogen gas, which is facilitated by
microorganisms that have been placed in a low oxygen, or anoxic environment.
Biological Nutrient Removal facilities that employ nitrification, denitrification, and
biological phosphorus removal are becoming more and more common as communities
are faced with more stringent nutrient limits in their NPDES permits. Section 6 discusses
the selected wastewater treatment strategies that will be considered at the Yakima
Regional WWTP in the future.
2.3 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
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/6OO/4-9O/O27F, as amended) are performed in a
48-hour static test of Cenodaphnia dubia. Bi -monthly chronic WET testing is also
performed using Cenodaphnia dubia, and EPA test protocol (EPA/6OO/4-91/002, as
amended). The permit says "There shall be no significant acute toxicity in a test
concentration representing the acute cntical 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 173-2O1A-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 173-2O1A-100, and
equals fifteen and one tenth percent (15.1%) final effluent." If a statistically significant
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difference between the control and the test organisms indicates effluent toxicity, then the
permittee is required to begin an additional senes of monitoring. If this series shows
compliance, the permittee is allowed to return to the onginal 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 recently completed a Ti/Re because the treated effluent
had exhibited some toxicity to Cerodaphnia dubia on an intermittent basis. Cerodaphnia
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
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.
2.4 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 are attributable to infiltration. Section
10, Analysis of Existing Wastewater Collection Facilities, includes a more detailed
analysis of infiltration and inflow issues.
2.5 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 agncultural, domestic,
industrial, and/or potable use. The WDOE considers all groundwater to be a source or
potential source of drinking water, and is currently proposing regulations which require
any discharge to the subsurface geology to meet drinking water standards prior to
discharge. The following paragraphs describe the regulations protecting groundwater,
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and the wastewater disposal practices that are affected by these regulations. The disposal
of biosolids from the wastewater treatment facilities as it may effect groundwater is
addressed separately in Section 9.
2.5.1 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
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.
2.5.2 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 septage sludge is incorporated as intermediate fill on the
landfill cover. 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
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septage from a business. This restnction 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 trap pumpings. If the grease has been analyzed for metals and
petroleum hydrocarbons, meets certain criteria, and the water is separated from
the grease, the grease may be accepted at the Terrace Heights landfill.
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.
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
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accepting industrial septage. Each load of industrial septage disposed of at the WWTP
would need to be charactenzed 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.
2.6 Biosolids Management
The management of residual solids produced from the 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 7O.95J). There are several local,
state and federal regulations and guidance on biosolids management and disposal.
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.
Biosolids regulations have been developed by many states as well. These regulations vary
considerably from state to state. The objective in these states is to derive the maximum
resource benefits of the biosolids land application while protecting the environment and
public health.
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2.6.1 Washington Regulatory Guidance
1111 The disposal of biosolids produced in the treatment process varies from community to
P
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.
2.7 Land Application of Treated Wastewater
When properly designed and operated, land application systems can be advantageous
because of the assimilative capacity of plants for nutrients such as nitrogen and
phosphorus, the adsorption of heavy metals onto soils, and the degradation or
volatilization of organic constituents. Applying wastewater to agricultural land utilizes
the abilities of both the crops and the soil to provide additional treatment and removal of
organic pollutants and inorganic nutrients. Concerns are often 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. 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 agncultural 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.
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 Anzona,
California, Florida, Oregon, Texas, and Washington have developed regulations that
strongly encourage water reuse as a water resources conservation strategy. These states
have developed comprehensive regulations specifying water quality requirements,
treatment processes, or both, for the full spectrum of reuse applications. The objective in
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these states is to denve the maximum resource benefits of the reclaimed water while
• protecting the environment and public health.
2.7.1 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.
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. Monitonng
requirements for reclaimed water are shown in Table 2-4.
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Table 2-4. Washington State Monitoring Requirements for Reclaimed Water'
Parameter
Biochemical Oxygen
Demand
Sample Type & Frequency
Total Suspended Solids
Total Coliforms
Turbidity
Dissolved Oxygen
24-hour composite, collected at
least weekly
24-hour composite, collected at
least daily'`
Grab, collected at least daily
Continuous recording
turbidimeter
Grab, collected at least daily
Compliance Requirements
Shall not exceed 30 mg/L determined
monthly, based on the arithmetic
mean of all samples collected during
the month.
Shall not exceed 30 mg/L, determined
monthly, based on the arithmetic
mean of all samples collected during
the month.
Compliance determined daily, based
on the median value determined from
the bacteriological results of the last 7
days for which analyses have been
completed.
Filtered wastewater shall not exceed
an average operating turbidity of 2
NTU, determined monthly, and not
exceeded 5 NTU at any time.
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
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 2-5. Washington does not have specific unrestricted recreational reuse
regulations for reclaimed water.
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Table 2-5. Washington State Treatment and Quality
Requirements for Reclaimed Water'
Use
Type of Reclaimed Water Allowed
Class A
Class B
Class C
Class D
Irrigation of Nonfood Crops
Trees and Fodder, Fiber, and Seed Crops
YES
YES
YES
YES
Sod, Ornamental Plants for Commercial Use, and
Pasture to Which Milking Cows or Goats
Have Access
YES
YES
YES
NO
Irrigation of Food Crops
Spray Irrigation
All Food Crops
YES
NO
NO
NO
Food Crops Which Undergo Physical or
Chemical Processing Sufficient to
Destroy All Pathogenic Agents
YES
YES
YES
YES
Surface Irrigation
Food Crops Where There is No
Reclaimed Water Contact With
Edible Portion of Crop
YES
YES
NO
NO
Root Crops
YES
NO
NO
NO
Orchards and Vineyards
YES
YES
YES
YES
Food Crops Which Undergo Physical or
Chemical Processing Sufficient to
Destroy All Pathogenic Agents
YES
YES
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
YES
NO
NO
NO
Landscapes)
I Source: "Evolution of the Water Reuse Regulations in Washington State "
2.7.2 Water Reuse
Reuse of wastewater in the Yakima Metropolitan area may become economically and
politically feasible as the availability of irrigation water declines. The majonty of the
crops in the valley are food crops which require Class B water for surface irrigation and
Class A water for irrigation. Other uses of Class A water could be the irrigation of yards,
schoolyards, golf courses, playgrounds, and parks. The City of Yakima's imgation
system utilizes local surface water. Converting to 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 performed for the City's potable water supply. An initial opinion of
probable cost to provide added treatment for Class A wastewater reuse is $40 M to $50 M
in capital, and $4 M to $5 M in annual operations and maintenance 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 such as West
Valley, Apple Tree Golf Course Planned Development, or a large industrial user is
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established, the City will investigate the feasibility of treating and transporting reuse
water to the end user.
2.8 Wetlands for Wastewater Treatment
In improving wastewater effluent quality, many communities have considered wetlands
treatment. With anticipated increases in nutrient removal requirements, wetland
treatment of wastewater is an alternative that may be considered for removal of nitrogen
and some phosphorus.
2.9 Land Application of Food Processing Waste
A separate report entitled, "Industrial Wastewater Land Application System Engineering
Report" has been prepared which discusses the City's current sprayfield operation for
treatment and disposal of food processing waste.
2.10 Endangered Species
Tables 2-6, 2-7 and 2-8 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
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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 2-6. The operation of wastewater treatment facilities is not likely to affect
the viability of the plant species listed below.
Table 2-6. Plant Listing
Scientific Common State Federal
Name Name Status Status
Astragaluscolumbianus Columbia milk -vetch Threatened SC
Cypripedum fasciculatum Clustered lady's-slipper Threatened SC
Erigeron Basalticus Basalt Daisy Threatened C
Lobelia Kalmii Kalm's lobelia Endangered E
Lomatium Tuberosum Hoover's desert -parsley Threatened SC
Sisyrinchium Sarmentosum Pale blue-eyed grass Threatened SC
Tauschia Hooveri Hoover's tauschia Threatened SC
SC = Species of Concern. E = Endangered.
C = Candidate.
The animals and fish identified for protection by the U.S. Fish and Wildlife Service and
Washington Fish and Wildlife are presented in Table 2-7 and Table 2-8.
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Table 2-7. Animal Listing
Common
Name
Scientific
Name
State Status
Federal
Status
Gray Wolf
Grizzly Bear
Fisher
Columbian white-tailed deer
Woodland caribou
American White Pelican
Brown Pelican
Peregrine Falcon
Sandhill Crane
Snowy Plover
Spotted Owl
Western Gray Squirrel
Lynx
Aleutian Canada Goose
Bald Eagle
Ferruginous Hawk
Sage Grouse
Sharp -tailed Grouse
Upland Sandpiper
Marbled Murrelet
Western Pond Turtle
Oregon Silverspot Butterfly
Canis lupus
Ursus arctos
Martes pennanti
Odocoileus virginianus leucurus
Rangifer tarandus
Pelecanus erythrorhynchos
Pelecanus occidentalis
Falco peregrinus
Grus canadensis
Charadrius alexandrinus
Strix occidentalis
Sciurus griseus
Lynx canadensis
Branca canadensis leucopareia
Haliaeetus leucocephalus
Buteo regalis
Centrocercus urophasianus
Tympanuchus phasianellus
Bartramia longicauda
Brachyramphus marmoratus
Clemmys marmorata
Speyeria zerene hippolyta
E
E
E
E
E
E
E
E
E
E
E
T
T
T
T
T
T
T
E
T
E
E
E
T
SC
E
E
E
T
T
SC
PT
T
T
SC
SC
SC
T
SC
C
E = Endangered.
SC = Species of Concern.
C = Candidate.
T = Threatened.
PT = Proposed Threatened.
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Table 2-8. Fish Listing
Common
Name
Scientific
Name
State Status Federal
Status
Chum Salmon (Hood Canal)
Chum Salmon (Lower Columbia)
Sockeye Salmon (Lake Ozette)
Sockeye Salmon (Snake River)
Chinook Salmon (Puget Sound)
Chinook Salmon (Snake River)
Chinook Salmon (Upper Columbia)
Chinook Salmon (Lower Columbia)
Chinook Salmon (Snake River Fall)
Steelhead (Snake River)
Steelhead (Middle Columbia)
Steelhead (Upper Columbia)
Steelhead (Lower Columbia)
Bull Trout
Bull Trout (Columbia Basin)
Oncorhynchus keta
Oncorhynchus keta
Oncorhynchus nerka
Oncorhynchus nerka
Oncorhynchus tshawytscha
Oncorhynchus tshawytscha
Oncorhynchus tshawytscha
Oncorhynchus tshawytscha
Oncorhynchus tshawytscha
Oncorhynchus mykiss
Oncorhynchus mykiss
Oncorhynchus mykiss
Oncorhynchus mykiss
Salvelinus confluentus
Salvelinus confluentus
C
C
C
C
C
T
T
T
E
T
T
E
T
T
T
T
E
T
C
T
E = Endangered.
C = Candidate.
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.
2.10.1 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 spnng 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. A recent
unsuccessful Washington State legislative initiative, SB -5289, proposed stnngent water
quality and water quantity policies with regard to salmon recovery which, if enacted,
would have had significant impacted on municipal wastewater discharges. Some possible
results of a future successful salmon bill for the Yakima Regional WWTP are:
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D Likely to require tertiary treatment of wastewater effluent for removal of
phosphorus and for filtration pnor to discharge. (Estimated cost - $66,000,000
plus).
➢ 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.
2.11 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.
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 wnting and managing permits and any
enforcement action. The City was responsible for inspections and monitoring of the
business community.
As a result of Initiative 607 (prior to I-695), WDOE has 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.
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During negotiation for the current 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 is required to request full
delegation of the Pretreatment Program by July 1, 2000. If the City does not request
delegation by that date, it is considered a NPDES permit violation, and the City may be
liable for enforcement actions including fines of $27,500 per day. WDOE must respond
to the delegation request within 60 days but does not expect to complete the delegation
procedure until permit reissuance in 2002. As a fully delegated program, the City is
required to have the financial and personnel resources available to conduct the program as
set forth in 40 CFR403.8 (f) (3).
The City of Yakima is required to submit the following to WDOE no later than July 1,
• 2000:
•
> Legally Binding Agreements (Permits) with all 39 Significant Industrial User's
(SIU's)
➢ Spill Prevention Plan Review of all 39 SIU's
> Revised Sewer Use Ordinance
➢ Interlocal Pretreatment Agreements with the Terrace Heights Sewer District and
the City of Union Gap
➢ Technically based Local Discharge Limits
➢ Industrial User Survey
➢ Determination of Adequacy
Until the Pretreatment Program is fully delegated to the City, the WDOE is responsible
for issuing and enforcing State Waste Discharge permits for non-domestic dischargers to
the POTW. The City is working with the WDOE to identify and categorize all non-
domestic dischargers potentially requiring discharge permits, and ensunng that all permits
issued to non-domestic users of the Yakima Regional WWTP will meet the requirements.
Permits issued by WDOE include effluent limitations incorporated into agreements (e.g.
Letters of Understanding) between the non-domestic users and the POTW, and reference
the local limits established in the City's sewer use ordinance.
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The current Pretreatment Program has completed, or is performing, the following
elements under the partially delegated program:
➢ An Industnal Waste Survey identifying all industrial users subject to the program.
➢ An Enforcement Response Plan.
➢ An Accidental Spill and Slug Control Plan.
➢ A Sewer Use Ordinance establishing authority to carry out the partially delegated
program.
➢ A Manual of Procedures which includes:
• Procedures for updating local limits and industrial waste surveys.
• Procedures for collecting and evaluating Industrial User self-monitoring
reports.
• Procedures for POTW sampling and analysis.
• Procedures for biosolids sampling and analysis.
• Procedures for sample collection, preservation, and storage.
➢ Procedures for updating or modifying the program.
D. Procedures for preparing the annual pretreatment report.
➢ Technically based local limits. These were submitted to WDOE and are currently
being revised due to changes in WDOE criteria.
D. An evaluation of the financial programs, staffing, and organization that will carry
out the partially delegated program.
➢ A statement from the City Attorney that the POTW has the authority to apply and
enforce the program.
111/ In 1999 the Pretreatment Program completed the following:
➢ Tracked a total of 1600 businesses to determine their impact on the POTW. Of
these, 39 have SWD permits or are considered Significant Industrial Users
(SIU's). The remaining businesses are considered Minor Industrial Users
(MIU's), or Insignificant Users (IU's).
➢ Reviewed the Master Business License database on a monthly basis to determine
if there are new businesses that should be a part of the Pretreatment Program.
➢ Collected 667 samples from businesses for analysis by the Wastewater laboratory.
➢ Monitored the effluent from Terrace Heights and Union Gap a minimum of five
times per month.
➢ Monitored the influent and effluent to the WWTP six times to determine total
pollutant loading to the plant, and compliance with water quality standards.
➢ Monitored the effluent from the WWTP using bioassays six times during the year
to determine effluent toxicity.
➢ Conducted modeling to determine air emissions. -This must be done on a yearly
basis.
➢ Worked with the Yakima County Development Association, City Planning
Department, and the business community to inform prospective new businesses of
the pretreatment regulations.
➢ Notified the business community of new Federal and State regulations that affect
wastewater discharges.
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➢ Investigated groundwater and stormwater discharges into the sewer system.
➢ Monitored groundwater at the airport for possible DDT contamination.
After the City has been authorized to implement the full Pretreatment Program, 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). The Terrace Heights Sewer District and the City of Union Gap will be
required to develop delegated Pretreatment Programs of their own as part of the
requirements set forth in the Yakima Regional WWTP NPDES permit. City staff is
currently meeting with Terrace Heights and Union Gap to advise them of their
obligations. These programs must also be in place by July 1, 2000. One of the options
being considered is for the City's Pretreatment Program to manage, for a fee, the
Pretreatment Program in Terrace Heights and Union Gap. Even if the City does not
manage the Pretreatment Programs, the City of Yakima will be required to independently
verify compliance by the businesses in those jurisdictions. There are expected to be an
additional 30 to 40 permittees in Terrace Heights and in Union Gap that must be
monitored.
2.12 Air Pollution
2.12.1 The Clean Air Act and Rules for the Control of Air
Pollution in Washington
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 Clean Air Authority.
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 tm (PM10), total suspended particulate (TSP), sulfur oxides (SO), 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), chlonne, and specific VOCs such as
benzene. Other critena pollutants can be of concern when engine generators are present.
Each year the Yakima Clean Air Authonty requires sources of air contaminants to register
• and obtain a permit. They are required to fill out a registration questionnaire that
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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
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 H2S -
decreases as temperature decreases. H2S has recently been removed from the list of
hazardous pollutants in the Clean Air Act.
110 The Yakima Regional WWTP uses chlorine for disinfection and process uses. The
likelihood of significant chlorine emissions from the wastewater treatment facilities is
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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 (White 1992), and increases with
decreasing temperature. At the maximum concentration in the wastewater process streams
of 12 mg/1, 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.
2.12.2 Clean Air Act Risk Management Pians
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. Facilities which store regulated chemicals
above the threshold quantity are 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.
2.12.3 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: Chlonne 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 2-9.
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Table 2-9. Exempt Amounts of Compressed Gases
Conditions
Exempt Amount (ft3 at STP)
Unprotected by sprinklers, gas cabinets or separate rooms
Within gas cabinets in unsprinklered building
In sprinklered building, not in gas cabinets or separate rooms
In sprinklered building, within gas cabinets
650
1300
1300
2600
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.
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2.13 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 the water quality protection criteria given in paragraph 2.1.2. 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 contamination of dnnkmg 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.
2.14 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.
2.15 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. To better understand the
specific requirements of a stormwater permit in the State of Washington, a copy of the
stormwater permit for the City of Seattle (a Phase I city) was obtained from WDOE.
Major points of the City of Seattle permit are summarized below.
The City of Seattle stormwater permit requires ongoing efforts to meet surface water
quality standards, groundwater quality standards, and sediment standards. These
requirements far exceed the narrative performance standards set forth in the Phase II
Stormwater regulations. WDOE requires modification of an existing stormwater program
to include Total Maximum Daily Loading (TMDL's) within four months of a TMDL
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being approved by WDOE. Since the TMDL for the Lower Yakima is already in place,
the TMDL requirements for the City of Yakima will be in the stormwater permit. The
Lower Yakima watershed includes the Yakima River from the confluence of the Naches
River, south to the Columbia River.
The Seattle permit is more restrictive than EPA's Phase I Storm Water Regulations, and
includes:
➢ Each permittee must develop a stormwater program.
➢ Stormwater programs shall contain:
• Descnption of the planning process, including public participation;
• Analysis of needs, including prioritization and an implementation plan and
schedule;
• Legal authority to control discharges to the storm sewer system, including
inspection and monitoring. Unlike the pretreatment program, this legal
authority must cover non -industrial dischargers;
• A monitoring program for discharges to evaluate impacts on surface waters
and sediments. This must identify pollution sources and evaluate
effectiveness of Best Management Practices (BMP's) as defined by WDOE;
• A fiscal analysis of staff, equipment, and support necessary to implement the
program, and the funding sources to support it;
• A mechanism for gathering and maintaining information. This must include:
• Known outfalls;
• A map of the storm sewer system;
• A map showing land use;
• A map depicting zoning;
• A database including precipitation records, stormwater quality records,
receiving water characteristics, and stormwater treatment areas.
• Identification of watershed wide coordination, including:
• Development of coordinated stormwater programs with other permittee's;
• Coordination of data management with other permittee's;
• Coordination of monitoring and modeling with other permittee's.
• Stormwater Control
• A program to control runoff from new development including permitting
and inspection procedures;
• Appropriate treatment and source control (as defined by WDOE) to reduce
pollutants in urban runoff;
• Operations and maintenance programs for stormwater treatment facilities;
• Practices for maintaining streets to reduce runoff contaminants;
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• A program to include water quality considerations in flood management;
• A program to reduce fertilizer and herbicide runoff;
• A program to detect illicit discharges, including:
- Prohibition of discharge to the stormwater sewer unless permitted by
WDOE;
- Monitoring and elimination of illicit discharges;
- Spill control and response procedures;
• A program to reduce pollutants from industrial facilities, including:
- Procedures to identifying industrial dischargers;
- A field inspection program, to assess compliance;
- A program to monitor industrial stormwater discharges.
• A community awareness program, including:
- Education on use and disposal of fertilizers and pesticides;
- Training of contractors on developing stormwater site plans and
BMP's for construction;
- Explaining to the public the definitions and impacts of illicit
discharges;
- Activities to explain and promote the proper management and disposal
of used oil and toxic materials.
• The City of Seattle must file an annual report with WDOE, including:
> Status of the program, including compliance schedule updates and program
modification,
> Notification of recent or proposed annexations,
> Differences between planned and actual expenditures,
> Revisions, if necessary, to the fiscal plan,
> In the fourth year, a summary of all monitoring data,
> A summary of all compliance activities,
➢ Identification of all known water quality improvements or degradations,
➢ Status of watershed -wide coordination efforts.
The City of Yakima will be required to coordinate with other permittees' in the
watershed. The EPA Phase II Storm Water Regulation specifically lists the following
communities in the Lower Yakima Watershed:
Selah
Yakima
Union Gap
Yakima County
Sunnyside
Benton County
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Under the EPA Phase II Regulation the current exemption for some municipal and
industrial operations will be eliminated. The Yakima Regional WWTP, the City of
Yakima Water Treatment Facility, and the City of Yakima Public Works Facility will
have to apply for industrial stormwater permits.
In 1993, HDR Engineering, Inc. prepared the Comprehensive Storm Water Management
Plan, and the Drainage Criteria and Design Manual for the City of Yakima which
provides the information needed to comply with the EPA Phase 11 Storm Water
Regulations.
The Comprehensive Storm Water Management Plan included a series of
recommendations including:
➢ create a Storm Water Utility with an initial assessment of $3 per equivalent
residential unit (ERU) up to a projected $6 per ERU to finance the Capital
Improvement Program, and the operations and maintenance of the Storm Water
Utility
D develop a $21 million Capital Improvement Program to improve drainage in the
City of Yakima downtown area, create storm water retention ponds at the major
outfalls to the Yakima River and Wide Hollow Creek, improve dry well
performance, and construct a by-pass at Union Gap for Wide Hollow Creek
➢ provide staffing adequate to operate and maintain the physical systems, manage
the utility, and administer the technical aspects of permitting, monitonng, testing,
and other compliance activities
Adoption and implementation of the recommendations included in the Comprehensive
Storm Water Management Plan, with some updates and modifications, may be necessary
now that the EPA Phase II Storm Water Regulations are finalized.
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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
Pnor 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, apncots, 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 16`h 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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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 I1-2
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 3
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C
B
6 5 1 4 1 3
fi
SCALE
2500 0 2500 5000
FEET
LEGEND:
AREA DESIGNATED FOR URBAN DEVELOPMENT
BY URBAN AREA PROVISIONAL PLANNING
COUNCIL — 1976
— 1982 FOUR PARTY AGREEMENT URBAN
SERVICE BOUNDARY
FOUR PARTY AGREEMENT
URBAN GROWTH AND URBAN
RESERVE BOUNDARY
YAKIMA
URBAN
RESERVE
2
-r
CITY OF YAKIMA
UNION GAP
URBAN RESERVE
UNION GAP
C— SERVICE
AREA
CITY OF
UNION GAP
TERRACE HEIGHTS
SEWER DISTRICT
TERRACE HEIGHTS
URBAN
RESERVE
HDR Engineering, Inc.
111
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
THIS UNE IS ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
m
z
YAK MA FOUR PARTY
AND URBAN AREA
=?gore 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
22.3'
Maximum Daily
25.0
25.0
--
Peak
36.0
27.0
32.02
BOD, Ibs/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, Ibs/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
1 Maximum Monthly AD must be tied to BOD, TSS, and NH4 loadings
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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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
78,987'
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
13,812"
23,420
20,420
2.503
8,168"
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 Area 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 occurnng 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 14
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 86 517 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
primanly 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:
➢ Weirman-Naches-Ashere: Very deep, well drained, nearly level to gently sloping
and generally located on floodplains and low terraces.
➢ 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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
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DRAFT
➢ 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
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 8
DRAFT
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
6
5
4
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YAKIMA WATER
411 TREATMENT PLANT
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HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILfTY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
THIS LINE IS ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
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i
EXISTING WATER
SYSTEM
rigure Number
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 imgation 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 imgation 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:
> 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
6
T1ETON PROJECT
COWICHE CREEK
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IRRIGATION SYSTEM PIPING
CANALS, RIVERS AND CREEKS
HDR Engineering, Inc.
•
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WASTEWATER
FACI LITI ES
PLAN
Project Manager
A. KRUTSCH
Designed
C DOLSBY
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
FEBRUARY 2000
THIS LINE IS ONE INCH WHEN
DRAWING S FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
a
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 i to 3 inches in
diameter and have been flushed each spring and once every three or four weeks to clean
out deposits in the imgation 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.
CITY OF YAKIMA
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PAGE 13
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Table 3-4. City of Yakima Commercial Flowratesl
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)
Avera e Dail
Flow (1 . ad)
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 gall/student
20 gall/student
25 gall/student
30 gall/student
300 gall/bed
200 gall/bed
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 industnal 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
I 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 matenals 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 industnal 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 industnal 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 industnal 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 loads 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
summanzes 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 (NH4) 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%).
➢ In the winter, low flow penod, the Yakima Regional WWTP has reduced the
infiltration and inflow (1/I) 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
Flow, mgd
BOD, mg/1
BOD, lb/d
TSS, mg/1
TSS, lb/d
NH4, mg/1
NH4, lb/d
1985 Low Flow
Periods, 3
12.8
357
38,200
248
26,500
15
1,650
1997-1999 Low Flow
Period2'3
10.3
260
22,270
234
22,040
19
1,627
1985 High Flow
Period1'4
20.5
257
44,000
175
30,000
10
1,700
1997-1999 High Flow
Period2'4
144
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
comdor. Residential land use types range from the older established residential
neighborhoods immediately to the east and west of the north -south commercial and
industrial stnp, to the newer residential developments in West Valley and Terrace
Heights.
Dunng 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 comdor, 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 YAKIMA
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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%
Public/semi-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
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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%
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
City Limits (acres) Acreage (acres)
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%)
30%
24%
7%
8%
16%
100%
111
(66)
1606
325
27
2069
Total
Acres
526
(377)
2,414
981
227
208
429
4,785
Percent of Total
Acreage
11%
(8%)
50%
21%
5%
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 boundanes 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
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D
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B
A
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DRAINAGE BASINS
1982 URBAN SERVICE BOUNDARY
URBAN RESERVE
UNION GAP URBAN GROWTH AREA
YAKIMA
URBAN
RESERVE
BASIN E
URBAN
TERRACE HEIGHTS
SEWER DISTRICT
UNION GAP
URBAN RESERVE
BASIN D
UNION GAP
SERVICE
AREA
L
TERRACE HEIGHTS
URBAN
RESERVE
HDR Engineering, Inc.
1
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
THIS UNE 15 ONE INCH WHEN
DRAWING S FULL SIZE IF NOT
ONE INCH. SCALE ACCORDINGLY.
0
0
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YAK MA URBAN
AREA DRAINAGE
BASIN BOUNDARIES
Figure Number
3-4
DRAFT
• Table 3-12. Drainage Basins
Basin Description
1986 Area
Served'
1999 Area
Developed2
2025 Area
Developed2
A Downtown, Eastern area from railroad 1,373 acres
tracks to 11`h Street.
B Downtown, Western area from railroad 2,276 acres
tracks including Carriage Hill, also
including Fruitvale. Generally north of
Lincoln Avenue.
C Includes memorial Hospital, Yakima 1,206 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
being the area between the Mead and
South Broadway.
E Includes areas between Nob Hill and 3,707 acres
Mead, as well as all properties West of
34th Avenue and Carriage Hill. Includes
unincorporated West Valley Area.
F East Yakima area between 11`h Street 245 acres
and Yakima River. Southerly boundary
extends to Rudkin Road Pump Station.
Includes County fairgrounds and
Fairview -Sumac area.
2,020 acres 2,108 acres
2,274 acres 3,830 acres
1,103 acres 1,232 acres
1,394 acres 1,993 acres
2,602 acres 7,346 acres
455 acres 1,045 acres
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 21
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r+1
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0 2500
5000
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DRAINAGE BASINS
FER
HDR Engineering, Inc.
CRY OF YAKIMA
YAKIMA REGIONAL
FACILRY
WASTEWATER TREATMENT
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 S FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
v
0
a
Description
Z
YAKIMA URBAN
AREA DRAINAGE
SUBBASIN
BOUNDARIES
Figure 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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
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 (1)
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 41ie 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/1, 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.
HDR ENGINEERING, INC
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 24
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 (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/1, 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.
HDR ENGINEERING, INC
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
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 Desiarn Critera
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 (lb/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 (lb/day) (16)
887
1,047
1,459
1,459
2,661
SS Maximum Month (lb/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 less 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. 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 storm event.
(1 1) Infiltration and Inflow (gpm) = (Inflow in gpad + Infiltration in gpad) x (Sewered Area 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 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/1, TSS = 172 mg/1)
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 25
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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 Commercial 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
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1500 0 1500 3000
G� —
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LEGEND:
COWICHE CANYON
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
COWICHE CANYON
WILEY CITY
COOUDGE OCCIDENTAL
WEST WASHINGTON
WIDE HOLLOW
WEST AIRPORT
SOUTH AIRPORT
URBAN SERVICE AREA BOUNDARY
WASTEWATER
FACILITIES
PLAN
L
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
WIDE HOLLOW
CITY OF YAKIMA
URBAN GROWTH AREA
THIS UNE IS ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE INCH. SCALE ACCORDINGLY.
WEST WASHINGTON
COOJDGE OCCIDENTAL
WEST AIRPORT
CITY OF
UNION GAP
WILEY CITY
SOUTH AIRPORT
0
z
YAK MA URBAN
AREA SEWER
BASIN BOUNDARIES
rigure 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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 28
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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 1,835" 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 3,5003 4 14,000
Subtotals 6,000 3,500 14,000
Union Gap Urban Growth
Area/Reserve
Low Density Residential5 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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CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
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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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
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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-pnvate 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 boundanes 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 nvers 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 dner
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
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2
NACRES
RIVER
YAKIMA
RIVER
2500
1+I
SCALE
0 2500
5000
LEGEND:
FEET
FEMA 100 YEAR FLOODPLAIN
CANALS, RIVERS AND CREEKS
BACHELOR CREEK
HDR Engineering. Inc.
IP
CRY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
E. MCDERMOTT
Checked
Number
06539-035-002
Date
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
0.
NATURAL
WATERWAYS
IN THE YAKIMA
URBAN AREA
Flgure Number
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:
D 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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 35
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL.
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACI LITI ES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
THIS LINE IS ONE INCH WHEN
DRAWING IS FULL SIZE. IF NOT
ONE INCH, SCALE ACCORDINGLY.
a
YAKIMA URBAN
AREA WETLANDS
rigure 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
industnal 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
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The following steps will help to reduce future groundwater contamination.
D Avoid septic tanks and drainfields in the Yakima Urban Area.
➢ Implement education and public awareness programs concerning water quality
issues.
➢ Continue programs for the collection and disposal of hazardous waste.
➢ 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:
➢ Effects of flooding on human health, safety and public facilities and services.
➢ 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.
➢ 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 h'EMA maps include many cntical areas protected under
the Growth Management Act. Therefore, the existing floodplain actually serves a much
broader purpose of protecting these cntical 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:
➢ Areas where endangered, threatened, and sensitive species have a primary
association.
➢ Habitats and species of local importance.
➢ Naturally occurring ponds under 20 acres and their submerged aquatic beds that
provide fish or wildlife habitat.
➢ Waters of the State of Washington.
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EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
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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 FEMA 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 YAKIMA
EXISTING AND PROJECTED SERVICE AREA CHARACTERISTICS - OCTOBER 6, 2000
PAGE 39
5
5
4
3
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1 V>
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t ct
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SCALE
5000 0 5000
10000
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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
THIS LINE IS ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE INCH. SCALE ACCORDINGLY.
LEGEND:
HABITAT AREAS
a
z
YAK MA URBAN
AREA WILDLIFE
HABITAT AREAS
Figure Numaer
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 onginal 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 distnbution 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.
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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 bactena 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.
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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.
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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
3.19.3.1
Special Considerations
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.
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PAGE 44
•
•
DRAFT
City of Yakima
Mandatory Wastewater Facilities Plan
SECTION 4
Existing and Projected Wastewater
Characteristics
October 2000
prepared by
Dan Harmon
HDR Engineering, Inc.
reviewed by
John Koch
Tony Krutsch
City of Yakima
•
DRAFT
Table of Contents
4.1 Introduction 1
4.2 Wastewater Facilities Study and Service Areas 1
4.3 Population Projections 1
4.4 Current Wastewater Characteristics 3
4.5 Projected Flows and Loadings 7
4.6 Allocation of Flows and Loadings 11
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City of Yakima
SECTION 4
Existing and Projected Wasteload
Characteristics
4.1 Introduction
Developing realistic flow and loading projections is critical to defining the facilities and space
required for near-term, year 2020, 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 (nitrogen and phosphorus). 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 Wastewater Facilities Study and Service
Areas
The population served establishes the quantity of domestic wastewater. The size and physical
characteristics of the Service Area and condition of the collection system determine the quantity of
extraneous flow.
4.3 Population Projections
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
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DRAFT
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 4-1. The projections roughly
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.
Table 4-1. Projected Residential Population for Wastewater Facilities Service
Areal
Current Year Year Year Year Buildout°
Population 20052 20102 2015 20202
Yakima Urban Service Area 78,987 87,900 96,500 100,000 102,000 106,600
Union Gap Urban Service Area/Reserve 6,477 7,061 7,506 7,930 8,494 20,438
Terrace Heights Urban Service Area/Reserve 4,715 6,080 6,770 7,324 8,490 14,145
Subtotal
Yakima Urban Reserve3
Total Service Area Population
90,179 101,041 110,776 115,254 118,984 141,183
3,000 5,695 8,704 13,812 23,420 36,317
93,179 106,736 119,480 129,066 142,404 177,5005
1 Based upon population projections presented in Section 3 Current Population presented is for 1998.
2. Projected population numbers using extrapolation of population data presented in Section 3
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 in Section 3.
Based on the projections in Table 4-1, 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 4-2 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 2020, and buildout
conditions.
Table 4-2. Percentage Growth of Service Area Populations
Current Year 2020 Buildout
Service Area Population 93,179 142,404 177,500
Yakima Urban Service Area 84 77% 71 63% 60 06%
Union Gap Urban Service Area/Reserve 6.95% 5.97% 11.51%
Terrace Heights Urban Service Area/Reserve 5.06% 5.96% 7.97%
Yakima Urban Reserve 3.22% 16.45% 20.46%
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED WASTEWATER CHARACTERISTICS - OCTOBER 6, 2000
PAGE 2
•
DRAFT
4.4 Current Wastewater Characteristics
The characteristics of the wastewater, including volumetnc 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
nitrates). In natural aquatic systems, the oxidation of ammonia to nitrates also consumes
dissolved oxygen. An additional consideration is that unionized ammonia is toxic to aquatic life
in low concentrations under some pH conditions.
For the Yakima wastewater treatment facility, the following general approach was used for
development of projected flows and loadings:
➢ Collection, trend -plotting, and evaluation of historical flow and loading data. Data from
years 1994 through 1999 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 known seasonal industrial discharges
(October/November). As a result, annual average flows and critical design periods were
selected as the baseline conditions for 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. In some cases, where data
were erratic, selection of an appropriate value involved judgment based on trends
observed in similar facilities.
Historical Flows and Loadings
Historical Annual Average Flow, BOD, TSS, and NH4 data for the Yakima Wastewater
Treatment Plant from 1994 through 1999 are presented in Table 4-3. The highest annual average
flow of 12.96 mgd, recorded in 1996, is less than the design annual average flow of 20.7 mgd,
and the permit maximum month flow of 22.3 mgd. Similarly, the current organic (BOD) and
solids (TSS) loading conditions are less than permit values.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED WASTEWATER CHARACTERISTICS - OCTOBER 6, 2000
PAGE 3
•
DRAFT
Table 4-3. Yakima Historical Influent Flows and Loadings'
Year
Flow,
mgd
BOD, Ib/day TSS, lb/day NI-I4i Ib/day2
1994 11.57 20,320 21,225 2,222
1995 12.79 19,247 20,180 2,469
1996 12.91 19,711 21,104 1,749
19974 11.47 19,173 17,916 1,659
1998 11.08 19,726 17,723 1,686
1999 10.32 21,204 17,022 1,787
Average 11 69 19,897 19,195 1,929
Permit3 22.35 30,300 24,300
1 Annual Average flow and Load conditions.
2. Ammonia data adjusted. Questionable data points in 1995 & 1996 eliminated.
3 NPDES Permit, Per Table 17-1, Yakima Regional O&M Manual, 1992, Updated 1997
4 Influent Parshall flume metering facilities modified, 1996. New metering facilities in operation in 1997
5. Maximum month average daily condition per O&M Manual.
The daily flow trend for years 1994 through 1998 are presented in Figure 4-1. The flow trend
shows influent 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.
25
20
E 15
0
u.F
Z
W
u. 10
0
1/1/94
Figure 4.1. Yakima Historical Influent Flows
__ --'SFJ -- -__ - - -_ _-- _ _ __ _ _ _ __ � _ _ _ _ _ _ •
1
v-
6/30/94
12/27/94 6/25/95
12/22/95
6/19/96
DATE
12/16/96
6/14/97
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED WASTEWATER CHARACTERISTICS - OCTOBER 6, 2000
12/11/97
6/9/98
12/6/98
PAGE 4
•
DRAFT
Several anomalies exist in the historical flow and loading data. Influent flows show a continual
gradual rise from 1994 through 1996, as would be expected as more connections are made to the
wastewater collection system. Flows then decrease significantly from 1996 to 1999. The
influent BOD, TSS, and ammonia loadings showed a general decline from the 1994 values
through 1999. The data also shows a significant reduction in solids (TSS) concentration from
1996 to 1999. 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 industrial/commercial
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 1997 through 1999 were chosen for
development of the baseline conditions. Baseline flow and loading conditions are presented in
Table 4-4. In addition to monthly average and maximum day conditions for all data, three
critical design periods were selected to coincide with the startup and shutdown of the irrigation
systems and the commercial/industrial discharges.
Table 4-4. Yakima Baseline Influent Flows and Loadings'
1. Flow and load conditions from 1997 through 1999 data set.
The data presented in Table 4-3 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 1997-1999 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 imgation is abrupt, resulting in flow
changes that occur within a few days from startup or shutdown of the irrigation systems.
➢ During the period between mid October and mid November, 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 flow conditions do
not coincide with peak organic and solids loading conditions.
➢ Average monthly BOD and TSS loadings are relatively constant, with episodes of
extremely high influent loads in both the March and October -November time periods.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED WASTEWATER CHARACTERISTICS - OCTOBER 6, 2000
PAGE 5
All Mo.
All,
March
Aug.
Oct.-
March
Aug.
Oct.-
Peak
Avg.
Max
Avg.
Avg.
Nov.
Max
Max
Nov.
Hr.
Day
Avg.
Day.
Day.
Max
Day.
Flow, mgd
11.28
15.25
9.39
14.38
10.27
11.03
15.25
12.50
24 0
BOD, lb/d
19,450
38,051
20,853
17,707
23,179
35,203
26,849
38,051
TSS, Ib/d
17,820
60,757
18,466
16,783
20,032
40,004
32,051
60,757
NH4, lb/d
1,678
2,563
1,935
1,490
1,644
2,563
1,950
2,136
1. Flow and load conditions from 1997 through 1999 data set.
The data presented in Table 4-3 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 1997-1999 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 imgation is abrupt, resulting in flow
changes that occur within a few days from startup or shutdown of the irrigation systems.
➢ During the period between mid October and mid November, 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 flow conditions do
not coincide with peak organic and solids loading conditions.
➢ Average monthly BOD and TSS loadings are relatively constant, with episodes of
extremely high influent loads in both the March and October -November time periods.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED WASTEWATER CHARACTERISTICS - OCTOBER 6, 2000
PAGE 5
•
DRAFT
BOD measurements increase by a factor of approximately 1.7 and TSS measurements
increase by a factor of approximately 3.0 from average month to maximum month
conditions, and 1.95 and 3.40 respectively when comparing peak day to annual average
conditions.
Wastewater Unit Flows and Loadings
Projections of future wastewater flow and loadings are 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.
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 Wastewater Treatment Plant, presented in Table 4-5, are
calculated based on the current population and the total influent flow (this method attributes all
flow — commercial and residential — to residents served by the Yakima Regional WWTP).
• Table 4-5. Baseline Unit (Per -Capita) Flows for Yakima WWTP
•
Design Period Flow, mgd Residential Population 1 Unit Flow, gpcd
76,000
Annual Average 11.28 148
Maximum Day 15.25 200
March
30 day 9.39 124
Max. Day 11.03 145
August
30 day 14.38 190
Max Day 15.25 200
October -November
30 day 10.27 135
Max Day 12.50 165
1 Estimated residential population for 1999 served by the wastewater treatment facility of a total population of
90,179.
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 imgation system piping. As the unit flows are calculated on a
"residential only" basis, changes in types of commercial (commercial, industrial, and
institutional) activities will impact the per -capita flow calculation. Also, conservation and
reduced inflow will reduce the per -capita projections. For planning purposes, it is anticipated that
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED WASTEWATER CHARACTERISTICS - OCTOBER 6, 2000 PAGE 6
DRAFT
the extraneous flow, infiltration/inflow, and commercial/industrial contributions will continue to
decrease the per capita unit flow over the planning period.
Unit Wasteload Determination
Wasteload projections (lb/day influent BOD, TSS, and ammonia) are typically determined using
planning flow projections and average influent concentrations. As the result of the variability in
loadings, primarily due to impact from industrial discharges, 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
three critical design periods, and annual average and maximum day conditions based on a
Service Area population currently connected to the Yakima Regional WWTP of 76,000.
Table 4-6. Baseline Unit (Per -Capita) Loadings for Yakima WWTP
Design Period
Influent Loadings Unit Loadings
BOD, TSS, NH4, Residential BOD, lb TSS, Ib NH4, Ib
lb/d lb/d Ib/d Population) pcd pcd pcd
76,000
Annual Average 19,450 17,820 1,678 0.25 0.23 0 022
Maximum Day 38,051 60,757 2,566 0.50 0.80 0.034
March
30 day 20,853 18,466 1,935 0.27 0.24 0 025
Max. Day 35,203 40,004 2,563 0 46 0.52 0.034
August
30 day 17,707 16,783 1,490 0.23 0.22 0.020
Max Day 26,849 32,051 1,950 0.35 0.42 0.027
October -November
30 day 23,179 20,032 1,644 0.30 0.26 0 022
Max Day 38,051 60,757 2,136 0.50 0.80 0028
1 Estimated residential population for 1999 served by the wastewater treatment facility of a total population of 90,179.
The unit loadings presented in Table 4-6 indicate the following:
➢ The influent 30 -day average BOD unit loadings do not fluctuate significantly between the
critical months.
➢ There is a rise in the maximum day TSS during the months of October -November, due to
industrial impacts. The 30 -day average TSS unit loadings do not vary significantly
between the critical months.
➢ Ammonia loadings do not vary significantly between the critical months analyzed.
➢ Unit loadings for BOD, TSS, and Ammonia are generally higher than other similar
facilities for the annual average and average monthly conditions.
4.5 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/commercial
influence of high strength wastewater on the per capita unit loadings is expected to decrease.
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PAGE 7
DRAFT
Table 4-7 identifies the per capita loadings of flow, BOD, TSS, and ammonia to be used in this
Wastewater Facilities Plan.
Table 4-7. Future Per Capita Unit Loadings for Yakima WWTP
Design Period
Unit Loadings
Flow BOD, lb TSS, lb N114, lb
gpcd pcd pcd pcd
Annual Average
Maximum Day
March
30 -day
Max Day
August
30 day
Max Day
October -November
30 day
Max Day
126 0.22 0.20 0.019
170 0.42 0 68 0.029
104 0.23 0.20 0 022
123 0.39 0.45 0 029
160 0 19 0 19 0 017
170 0.30 0.36 0 022
114 0.25 0.22 0 018
139 0 42 0 68 0 024
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. At the present time, the Yakima Regional WWTP
only provides sewer service to 76,000 people out of a total Service Area population of 93,179, or
approximately 82 percent. Although it is anticipated that the percentage of the population served
in 2020 will increase, it is unlikely that all residential, commercial, industrial, and institutional
customers within the Service Area will be connected to the sewerage facilities.
Future Planning Projections
Table 4-8 shows the projected flows and loadings for the Yakima WWTP. These values were
developed using the population projections presented in Table 4-1, and baseline unit flows and
loads presented in Table 4-7.
The peak conditions for BOD and TSS are higher for the March and October -November critical
design months, due to commercial/industrial influence. The projections anticipate that
commercial/industrial loadings will increase proportional to residential contributions
Table 4-8. Projected Flow and Loadings for the Yakima Facility
Year
Condition
Flow, mgd
BOD, lb/d
TSS, lb/d
NH4, lb/d
1997/99
Annual Avg.(Baseline)
11.28
19,450
17,820
1,678
March
30 -day avg.
9.39
20,853
18,466
1,935
Max Day
11 03
35,203
40,004
2,563
Peak Hour
24 03
August
30 -day avg.
14.38
17,707
16,783
1,490
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PAGE 8
DRAFT
Table 4-8. Projected Flow and Loadings for the Yakima Facility (Cont.)
Year
Condition
Flow, mgd
BOD, lb/d
TSS, lb/d
NH4, lb/d
Max Day
15.25
26,849
32,051
1,950
Peak Hour
24 03
October -November
30 -day avg.
10.27
23,179
20,032
1,644
Max Day
12.50
38,051
60,757
2,136
Peak Hour
24 03
2005
Annual Avg.
13.45
23,482
20,600
2,028
March
30 -day avg.
11.10
24,549
21,347
2,348
Max Day
12.28
39,184
44,527
2,853
Peak Hour
26.74
August
30 -day avg.
17.07
20,280
20,280
1,815
Max Day
18.15
32,020
38,425
2,348
Peak Hour
28.54
October -November
30 -day avg.
12.17
26,684
23,482
1,921
Max Day
14.84
44,829
72,580
2,562
Peak Hour
28.54
2010
Annual Avg.
15.05
26,286
23,060
2,270
March
30 -day avg.
12.43
27,480
23,896
2,629
Max Day
14.70
46,597
53,766
3.465
Peak hour
31 89
August
30 -day avg.
19 12
22,701
22,701
2,031
Max Day
20.31
35,844
43.013
2,629
Peak Hour
31.89
October -November
30 -day avg.
13.62
29,870
26,286
2,151
Max Day
16.61
50,182
81,246
2,868
Peak Hour
31 89
2015
Annual Avg.
16.26
28.395
24,910
2,452
March
30 -day avg.
13 42
29,685
25,813
2,839
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PAGE 9
DRAFT
Table 4-8. Projected Flow and Loadings for the Yakima Facility (Cont.)
Year
Condition
Flow, mgd
BOD, lb/d
TSS, lb/d
NH4, Ib/d
Max Day
15.88
50,336
58.080
3,743
Peak Hour
34 45
August
30 -day avg.
20.65
24,523
24.523
2,194
Max Day
21 94
38,720
46,464
2,839
Peak Hour
34 45
October -November
30 -day avg.
14 71
32,267
28,395
2,323
Max Day
17.94
54,208
87,765
3,098
Peak Hour
34 45
2020
Annual Avg.
17.94
31,329
27,490
2,706
March
30 -day avg.
14.81
32,753
28,480
3,133
Max Day
17.52
55,538
64,082
4,130
Peak Hour
38.01
August
30 -day avg.
22.78
27,057
27,057
2,420
Max Day
24.21
42,721
51,265
3,133
Peak Hour
38.01
October -November
30 -day avg.
16.23
35,601
31,329
2,563
Max Day
19.79
59,810
96,835
3,418
Peak Hour
38.01
Buildout
Annual Avg.
22.37
39.050
34,260
3,373
March
30 -day avg.
18.46
40,825
35.500
3,905
Max Day
21.83
69,225
79,875
5,148
Peak Hour
47.37
August
30 -day avg.
28.40
33,725
33,725
3,018
Max Day
30 18
53,250
63,900
3,905
Peak Hour
47.37
October -November
30 -day avg.
20.24
44,375
39,050
3,195
Max Day
24 67
74,550
120,700
4,260
Peak Hour
47.37
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CITY OF YAKIMA
EXISTING AND PROJECTED WASTEWATER CHARACTERISTICS - OCTOBER 6, 2000
PAGE 10
DRAFT
4.6 Allocation of Flows and Loadings
• The Yakima Regional WWTP provides service to the City of Yakima, the City of Union Gap, the
Terrace Heights Sewer District, and the unincorporated area of Yakima County lying west of the
Yakima city limits. The City of Union Gap has purchased 8.1 percent of the treatment capacity
of the Yakima Regional WWTP, and the Terrace Heights Sewer Distnct has purchased 4.0
percent of the treatment capacity of the Yakima Regional WWTP. The City of Yakima has
retained the remaining 87.9 percent of the treatment capacity which provides for the service
requirements of the City and the unincorporated area.
As noted previously in this section, as the population within the Service Area increases, the
percentage of growth will shift away from the existing City of Yakima to the City of Union Gap,
Terrace Heights Sewer District, and the Yakima Urban Reserve. Along with this change in
population will also come a change in the percentage contribution of wastewater characteristics
(flow, BOD, TSS, and ammonia). Table 4-9 shows the distribution of wastewater characteristics
based on current conditions, and anticipated distribution of wastewater characteristics for 2020
and buildout conditions.
•
Table 4-9. Maximum Month Average Daily Distribution of Wastewater Characteristics
1. From Union Gap General Sewer Plan. The second number shown in he percentage column for BOD and TSS is based on
projecting current unit loadings and population in lieu of the calculated ppd as shown in the UG General Sewer Plan (ie BOD -
3202 ppd, TSS - 2985 ppd in 2020 and BOD - 7705 ppd, TSS - 7182 ppd at Build -out).
2. From Terrace Heights General Sewer Plan.
3 Anticipated to be proportional to population. Union Gap and Terrace Heights did not report current or projected loadings for
Ammonia.
4 Flows and loads based on calculations in Table 4-5 and 4-6.
HDR ENGINEERING, INC.
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EXISTING AND PROJECTED WASTEWATER CHARACTERISTICS - OCTOBER 6, 2000
PAGE 11
Total
Service
Area
Yakima Urban
Area4
Union Gap'
Terrace Heights2
Yakima Urban
Reserve4
Amount
Percent
Amount
Percent (%)
Amount
Percent
Amount
Percent
(%)
(%)
(%)
Current Conditions
Population
90,179
78,987
87.59
6,477
7.18
4,715
5.23
0
0
Flow (mgd)
14.38
12.64
87 90
0 76
5.29
0.50
3 48
0
0
BOD (ppd)
23,179
19,747
85 19
2,442
10.54
670
2.89
0
0
TSS (ppd)
20,032
17,377
86.75
2,276
11.36
704
3.51
0
0
Ammonia (ppd)
1,9353
2020 Design Conditions
Population
142,404
102,000
71.63
8,494
5 96
8,490
5.96
23,420
16.45
Flow (mgd)
22.78
16.32
71 64
2.06
9 04
1 49
6.54
3 75
16.46
BOD (ppd)
35,601
25,500
71 63
6,603
18.54/8.99
1,206
3.39
5,855
16.45
TSS (ppd)
31,329
22,440
71 63
6,157
19 65/9.53
1,300
4 15
5,152
16.45
Ammonia (ppd)
3,1333
Buildout Conditions
Population
177,500
106,600
60 06
20,438
11.51
14,145
7.97
36,317
20 46
Flow (mgd)
28.40
17 06
60 07
564
19.86
1.92
6.76
5.81
20 46
BOD (ppd)
44,375
26,650
60.06
18,085
40 76/17.36
2,020
4.53
9,079
20.46
TSS (ppd)
39,050
23,452
60.06
16,860
43.18/18.39
2,107
5 40
7,990
20 46
Ammonia (ppd)
3.9053
_
_
1. From Union Gap General Sewer Plan. The second number shown in he percentage column for BOD and TSS is based on
projecting current unit loadings and population in lieu of the calculated ppd as shown in the UG General Sewer Plan (ie BOD -
3202 ppd, TSS - 2985 ppd in 2020 and BOD - 7705 ppd, TSS - 7182 ppd at Build -out).
2. From Terrace Heights General Sewer Plan.
3 Anticipated to be proportional to population. Union Gap and Terrace Heights did not report current or projected loadings for
Ammonia.
4 Flows and loads based on calculations in Table 4-5 and 4-6.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED WASTEWATER CHARACTERISTICS - OCTOBER 6, 2000
PAGE 11
DRAFT
In evaluating the results of Table 4-9 the following conclusions can be developed:
> The sum of the individual calculations for the Yakima Urban Area, the City of Union
Gap, the Terrace Heights Sewer District, and the Yakima Urban Reserve do not equal
the Total Service Area calculations as developed for this evaluation of the Yakima
Regional WWTP. This variance in the sum of the individual calculations is likely the
result of the methods used in the calculation of the individual service area
characteristics.
➢ The projections by Terrace Heights appear to be reasonable and generally conform
with expected population growth within the Yakima Service Area. Unit loadings for
BOD of 0.142 ppcd and for TSS of 0.149 ppcd are considered to be low. Flows from
the Terrace Heights Sewer District will likely exceed 4 percent of the maximum
month average daily flow entering the Yakima Regional WWTP by 2020. BOD and
TSS loadings will likely equal or exceed 4 percent of the influent loadings of BOD
and TSS to the Yakima Regional WWTP by 2020.
> At the present time, the City of Union Gap wastewater flows represent only 5.29
percent of the total influent flows entering the Yakima Regional WWTP. The BOD
and TSS influent loadings currently represent 10.54 percent and 11.36 percent of total
influent loading.
> The projections by the City of Union Gap appear to be extremely aggressive based on
expected population growth within the Yakima Service Area. Unit loadings are
projected to increase from 0.377 ppcd (BOD) to 0.777 ppcd (BOD) and 0.351 ppcd
(TSS) to 0.724 ppcd (TSS) by 2020. The existing unit loading rates of 0.377 ppcd
(BOD) and 0.351 ppcd (TSS) are already considered to be high in comparison with
unit loading rates within the City of Yakima (0.25 ppcd BOD, 0.22 ppcd TSS). If the
City of Union Gap unit loading rates exceed current unit rates, pretreatment of high
strength wastewater flows will be necessary rather than acceptance and treatment of
these flows at the Yakima Regional WWTP. Unit loading rates of 0.777 ppcd (BOD)
and 0.724 ppcd (TSS) are typically associated with high strength industrial waste
rather than domestic wastewater.
> It appears that the City of Union Gap will contribute approximately 9 percent of flow,
9 percent of BOD and 10 percent of TSS loadings to the Yakima Regional WWTP by
2020.
➢ The Yakima Urban Reserve area will see a significant increase in development and
population growth by 2020. Based on average wastewater characteristics, the Yakima
Urban Reserve will contribute approximately 16.45 percent of the hydraulic, BOD,
and TSS loadings to the Yakima Regional WWTP by 2020, and approximately 20.46
percent at build -out conditions.
At the next update of the Mandatory Wastewater Facilities Plan for the Yakima Regional
WWTP, the flow and loading projections for the City of Union Gap should be reviewed to
determine if the proposed increases are being observed. If these increases are being observed,
and pretreatment of high strength waste within the City of Union Gap is not required, significant
upgrades and modifications to the Yakima Regional WWTP will be needed which are not
planned for in this report.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED WASTEWATER CHARACTERISTICS - OCTOBER 6, 2000
PAGE 12
•
DRAFT
As discussed in Section 3, the City of Yakima was delegated with the mandatory responsibility to
construct, operate and maintain a wastewater treatment facility and interceptor sewers with
sufficient capacity to handle design flows as set forth in the Beck Study. Table 4-10 compares
the City of Yakima's mandatory responsibility, for providing wastewater treatment, as set forth in
the "Four Party Agreement" with the current rated capacity and current conditions at the Yakima
Regional WWTP.
Table 4-10. Comparison of Mandatory Requirements versus
Current Rated Capacity
Agency
Mandatory Requirements)
Rated Capacity
Current Conditions
Flow (mgd)
Flow (mgd)
Flow (mgd)
Max Mo AD
Peak
Max Mo AD
Peak
Max Mo AD
Peak
City of Yakima
10.30
14 95
19 60
28.13
13 13
20.96
City of Union Gap
0 48
0 74
1.813
2.593
0 765
1.765
Terrace Heights
Sewer District
0.28
0.51
0.894
1.284
0 495
1.285
Totals
11 06
16.20
22.302
32.002
14.386
24 066
1. From RW Beck 1976 Yakima Wastewater Facilities Planning Study
2. From Section 3
3. Based on 8.1%
4 Basedon40%
5 From Section 3
6. From Section 4
As shown in Table 4-10, based on hydraulic capacity, the City of Yakima has met and exceeded
the original mandatory requirements of the "Four Party Agreement" for construction of a
wastewater treatment facility. Since current hydraulic flows are in excess of the mandatory
requirements, it can be concluded that the City of Yakima has also met and exceeded the original
mandatory requirements of the "Four Party Agreement" for construction of interceptor sewers
with sufficient capacity to handle design flows.
Hydraulic capacity has a direct impact on sizing of sanitary sewer lines such as collection lines,
trunk sewers, and interceptors. Although the wastewater treatment plant must be capable of
passing the flows delivered by the sanitary sewer system, the primary purpose of the treatment
plant is to remove organic material, solids, ammonia, and pathogenic bacteria from the sewage
flow.
In review of the RW Beck 1976 Yakima Wastewater Facilities Planning Study, the design
loadings for wastewater characteristics as planned for at the wastewater treatment facility can be
developed for the year 2000. Table 4-11 identifies the planned wastewater characteristic and
current loadings for the City of Yakima, City of Union Gap, and the Terrace Heights Sewer
Distnct.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED WASTEWATER CHARACTERISTICS - OCTOBER 6, 2000
PAGE 13
•
•
• DRAFT
Table 4-11. 1976 Distribution of Maximum Month Wastewater Characteristics for 2000
Parameter
Yakima Urban
Union Gap
Terrace Heights
Total
Capacity
1976 Plan'
Current2
1976 Plan
Current2
1976 Plan
Current2
1976 Plan
Current2
Rated3
Population
78,550
78,987
2,710
6,477
5,600
4,715
86,860
90,179
134,200'
Flow (mgd) AD
17.33
12.64
1 01
0.76
0.76
0.49
19 10
14.38
22.30
Flow (mgd) Peak
25.31
21 12
2.14
1 76
1 72
0.73
27 01
24 03
32.00
BOD(ppd)
32,310
19,747
2,570
2,442
1,120
670
36,000
23,179
34,5005
TSS (ppd)
32,310
17,377
2,570
2,276
1,120
704
36,000
20,032
46,000
1 Includes West Valley as referred to in the 1976 Beck Study (62,650 City of Yakima, 15,900 West Valley)
2. From Table 4-9
3 From Section 3
4 Calculated based on BOD loading for current conditions
5 With MOSS at 2200 mg/I and trickling filter loading at 65 lb/kcf.
Based on the current rated capacity for flow, BOD, and TSS at the Yakima Regional WWTP, the City of Yakima has met and exceeded the
mandatory requirements of the "Four Party Agreement" for all wastewater characteristics.
HDR ENGINEERING, INC.
CITY OF YAKIMA
EXISTING AND PROJECTED WASTEWATER CHARACTERISTICS - OCTOBER 6, 2000
PAGE 14
DRAFT
• City of Yakima
Mandatory Wastewater Facilities Nan
SECTION 5
Analysis of Existing Wastewater
Treatment Plant
0 October 2000
prepared by
Dustin Nett/Dan Harmon
HDR Engineering, Inc.
•
reviewed by
John Koch
Tony Krutsch
City of Yakima
•
DRAFT
Table of Contents
5.1 Introduction 1
5.2 Permit Requirements 1
5.3 Influent Flows and Loads 2
5.4 Process Capacity Calculations 3
5.5 Process Unit Capacity Evaluation 12
5.5.1 Preliminary Treatment 12
5.5.2 Primary Treatment 14
5.5.3 Secondary Treatment 17
5.5.4 Final Disinfection 25
5.5.5 Outfall 26
5.5.6 Non -Potable Water System 27
5.5.7 Solids Thickening 28
5.5.8 Solids Digestion 28
5.5.9 Solids Dewatering 30
5.5.10 Miscellaneous Systems/Facilities 31
5.6 Summary 33
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT - OCTOBER 6, 2000
PAGEi
DRAFT
• City of Yakima
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, current
flow and loading conditions, and remaining capacity for each unit process at the Yakima
Regional Wastewater Treatment Plant. Additionally, operation and maintenance practices and
treatment plant staff issues will be reviewed. The analysis is based on:
➢ A review of operating data from January 1994 to December 1999. Following additional
data analysis, operating data from January 1997 to December 1999 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 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 Permit Requirements
Table 5-1 summarizes the current key effluent permit requirements for the City of Yakima
WWTP.
Table 5 -1. Summary of NPDES Permit Requirements'
Parameter Monthly Average2 Weekly Average Daily Maximum
Flow 22.3 mgd(max.month) N/A N/A
BOD5 30mg/L, (4,905 lbs/day) 45 mg/L; (7,358 lbs/day) N/A
TSS 30 mg/L, (5,250 lbs/day) 45 mg/L, (7,875 lbs/day) N/A
Fecal Coliform Bacteria 200 colonies/100 ml 400 colonies/100 ml N/A
pH 6.0 to 9 0 6.0 to 9 0 6.0 to 9 0
Ammonia, Total3 4 16 mg/L N/A 12.3 mg/L
Chlorine, Total 0 012 mg/L N/A 0.029 mg/L
1. Outfall No. 001 associated with WWTP, excludes food processing spray field.
2. Monthly average effluent concentrations for BOD5 and TSS shall not exceed 30 mg/L or fifteen percent (15%) of respective
monthly average influent concentrations, whichever is more stringent.
3 WET Testing — Acute Toxicity is required — this requirement will often place an indirect limit on ammonia.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
PAGE I
•
DRAFT
5.3 Influent Flows and Loads
Influent flows and load data analyzed between January 1997 and December 1999 shows a strong
seasonal character, due to the industrial load in fall, and high flows in August. Three critical
penods were selected for analysis: March, August, and October/November. The wastewater
characteristics are summarized in Table 5-2.
1 Concentrations calculated based on mass loads (lb/d)
2. Peak hour flow is based upon previous planning estimates.
3 Maximum represent maximum day conditions.
Ammonia data were edited to eliminate outliers which appeared to be questionable, showing very
high (>50 mg/L) ammonia concentrations. These high values were questioned because there is
no other evidence to suggest a peak load (such as higher BOD or TSS at the same time). The
high ammonia concentrations could be attributed to the sample being non -representative, or
analytical error. In addition, recent and more frequent data do not show such high ammonia
concentrations.
Future flows and loads developed as part of Section 4 are presented in Table 5-3. Flow and
loading projections for the years 2010 and 2020 are summarized. The table indicates flows and
loads are expected to increase by approximately 55 percent over the next 20 years.
Table 5-3. Projected Future Flows and Loads'
Year
Design Values Annual Average Max Month2 Max Day2 Peak Hour
Parameter
2010
2020
Flow mgd 15.05 1912 20.31
BODS Ib/d 26,286 29,870 50,182
TSS Ib/d 23,896 26,286 81,246
NH4 lb/d 2,270 2,629 3,465
Flow mgd 17.94 22.78 24.21
BODs lb/d 31,329 35,601 59,810
TSS lb/d 28,480 31,329 96.835
NH4 lb/d 2,706 3,133 4,130
31 90
38.01
1 Based upon population projections presented in Section 3 and projections presented in Section 4 for Year 2020 design
condition.
2. Worst-case conditions shown, based upon highest value from the three critical design periods (March, August, October -
November) evaluated.
HDR ENGINEERING, INC. PAGE 2
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
1 awe 5-z.
inriuenr Flows ana Loads
All Data
Average
All Data
Max
March
Average
August
Average
Oct -Nov
Average
March
Max
August
Max
Oct -Nov
Max
PeakHr
Flow
Mgd
11.28
15.25
9.39
14.38
10.27
11.03
15.25
12.50
24.0
BOD
Ib/d
19,450
38,051
20,853
17,251
22,292
35,203
26,849
38,051
TSS
lb/d
17,820
60,757
18,466
16,783
20,032
40,004
32,051
60,757
NH4
lb/d
1,678
2,563
1,935
1,490
1,644
2,563
1,950
2,136
Flow
Mgd
11.28
15.25
9.39
14.38
10.27
11.03
15.25
12.50
24 0
BOD
mg/L
207
383
266
144
260
383
211
365
TSS
mg/L
189
583
236
140
234
435
252
583
NH4
mg/L
18
28
25
12
19
28
15
20
TKN
mg/L
25
40
35
18
27
40
22
29
1 Concentrations calculated based on mass loads (lb/d)
2. Peak hour flow is based upon previous planning estimates.
3 Maximum represent maximum day conditions.
Ammonia data were edited to eliminate outliers which appeared to be questionable, showing very
high (>50 mg/L) ammonia concentrations. These high values were questioned because there is
no other evidence to suggest a peak load (such as higher BOD or TSS at the same time). The
high ammonia concentrations could be attributed to the sample being non -representative, or
analytical error. In addition, recent and more frequent data do not show such high ammonia
concentrations.
Future flows and loads developed as part of Section 4 are presented in Table 5-3. Flow and
loading projections for the years 2010 and 2020 are summarized. The table indicates flows and
loads are expected to increase by approximately 55 percent over the next 20 years.
Table 5-3. Projected Future Flows and Loads'
Year
Design Values Annual Average Max Month2 Max Day2 Peak Hour
Parameter
2010
2020
Flow mgd 15.05 1912 20.31
BODS Ib/d 26,286 29,870 50,182
TSS Ib/d 23,896 26,286 81,246
NH4 lb/d 2,270 2,629 3,465
Flow mgd 17.94 22.78 24.21
BODs lb/d 31,329 35,601 59,810
TSS lb/d 28,480 31,329 96.835
NH4 lb/d 2,706 3,133 4,130
31 90
38.01
1 Based upon population projections presented in Section 3 and projections presented in Section 4 for Year 2020 design
condition.
2. Worst-case conditions shown, based upon highest value from the three critical design periods (March, August, October -
November) evaluated.
HDR ENGINEERING, INC. PAGE 2
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
•
DRAFT
5.4 Process Capacity Calculations
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 accommodate organic and solids loadings. Organic strength is
measured by biochemical oxygen demand (BOD) and ammonia (NH4), and solids strength by
total suspended solids (TSS). Treatment unit sizing is based upon hydraulic, organic, and solids
criteria. The process calculations were conducted as follows:
The existing Yakima Regional Wastewater Treatment Plant 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 plant 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 process including:
➢ Installation of new trickling filter pumping.
D Increase laboratory space.
➢ Provide enhanced chlorination and dechlorination facilities.
➢ Installation of air emission equipment.
D 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.
➢ Installation of flexible membrane digester gasholder covers for the secondary digesters.
➢ Miscellaneous operating improvements.
A liquid treatment process schematic of the existing Yakima Regional Wastewater Plant is
shown on Figure 5-1 and an existing solids process schematic is presented in Figure 5-2.
Detailed sizing information for each unit process is presented in Figure 5-3. Figure 5-4 presents
the existing hydraulic profile.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
PAGE 3
6
5
4
3
2
RAS
PUMPING
STATION
CITY OF YAKIMA
RUDKIN
ROAD
PUMPING
STATION
K—MART
PUMPING
STATION
YAKIMA AND
UNION GAP
WEST EAST
DIVERSION DIVERSION HEADWORKS
STRUCTURE STRUCTURE BUILDING
TERRACE HEIGHTS
PUMPING STATION
DEGRITFER
NO. 1
DEGRITTER
NO. 2
FOOD PROCESSING
PUMPING
STATION
WASTE
PRIMARY
CLARIFIER
NO. 1
PRIMARY
CLARIFIER
NO. 4
TRICKLING
FILTER
PUMPING
STATION
TRICKLING
NORTH FILTERS
TRICKLING CLARIFIER
FILTER
INTERMEDLATE
DEGRITTER
BYPASS
OUTFALL
DECHLORINATION
BUILDING
PRIMARY
CLARIFIER
NO. 2
PRIMARY
CLARIFIER
NO. 3
SOUTH
TRICKLING
FILTER
CHLORINATION
BUILDING
RAS PUMPING SYSTEM
RAS
PUMPING
STATION
RAS
CHLORINE
CONTACT
TANKS
FE
SECONDARY
CLARIFIER
NO. 1
WAS PUMP ROOM
RAS
RAS
FE
SECONDARY
CLARIFIER
NO. 2
NO. 2
NO. 3
NO. 1
NO. 4
pi
AERATION BASINS
SECONDARY
CLARIFIER
NO. 1
SECONDARY
CLARIFIER
NO. 2
OUTFALL
HDR Engineering. Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FAC I LIT I ES
PLAN
Project Manager
A. KRUTSCH
Designed
O. NETT
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
DRAWING 5 FULL SIZE. IF NOT
ONE INCH. SCALE ACCORDINGLY.
0
0
0
z
EXISTING LIQUID
PROCESS
SCHEMATIC
Figure Number
5-1
6
3
2
1
1
C
B
A
a.
LEI
MI
EAST
DIVERSION
STRUCTURE
®-
MECH.
BAR
SCREENS
SCREENING
GRIT PUMP
VORTEX
DEGRITTER
NO. 1
TO PRIMARY CLARIFIER
INFLUENT
GRIT CLASSIFIER I I GRIT HOPPER
VORTEX
DEGRITTER
NO. 2
GRIT CYCLONE
TO PRIMARY CLARIFIER
INFLUENT
PRIMARY
CLARIFIER
NO. 1
SOLIDS PUMP
SCUM
❑SCUM
I� SOUDS II
PRIMARY
CLARIFIER
NO. 4
SCUM
7SOLIDS
DENSITY MTR
PRIMARY
CLARIFIER
NO. 2
SOLIDS TRANSFER PUMP
K
1CI
SECONDARY
DIGESTER
NO. 1
12
12
0•
SECONDARY
DIGESTER
\ N0. 3
101
SECONDARY
DIGESTER
NO. 2
PRIMARY
DIGESTER
NO. 3
SOLIDS
RECIRC
101 1q 101
SOUDS
TRANSFER
PUMP
12
101
PRIMARY
DIGESTER
NO. 2
12
12
SOUDS
RECIRC
PRIMARY
DIGESTER
NO. 1
TO SL/YPS
12
PRIMARY
CLARIFIER
NO. 3
SCUM PIT
TO LAND UTILIZATION
f
101 1♦
CAKE HOPPER
CENTRATE SUMP
CENTRIFUGE NO. 2
CENTRIFUGE N0. 1
1C1
TO LAND UTIUZATION
SOUDS DREDGE
12
12
SOLIDS DRYING
BEDS
TO LAND UTILIZATION
101
12
BIOSOUDS
CAKE
PUMP
12
I�
TO LAND UTILIZATION
32 •
I
DENSITY MTR
FLOW MTR
Iw�l
CENTRIFUGE\
FEED PUMP
DAF
THICKENER
TO YPS
12
32
— —#2-
THWASICKENED
PUMP
INTERMEDIATE
DEGRITTER
NO. 2
INTERMEDIATE
CRIT PUMPS
SCUM TO YPS
NO. 1
CHLORINE
CONTACT
TANKS
NO. 2
RAS
PUMPING
STATION A
� I
NO. 1
N0. 3
NO. 4
t29
DI DI
AERATION BASIN
101
WAS PUMP
SCUM PUMP
SCUM PI
SCUM P
N
SECONDARY
CLARIFIER
NO. 1
SECONDARY
CLARIFIER
NO. 2
ha(
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
D. NETT
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
THIS UNE IS ONE NCH WHEN
DRAWING S FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
0
0
m
0
z
EXISTING SOLIDS
PROCESS
SCHEMATIC
Figure Number
5-2
SOLIDS
—
IAGODN7
SOUDS DREDGE
12
12
SOLIDS DRYING
BEDS
TO LAND UTILIZATION
101
12
BIOSOUDS
CAKE
PUMP
12
I�
TO LAND UTILIZATION
32 •
I
DENSITY MTR
FLOW MTR
Iw�l
CENTRIFUGE\
FEED PUMP
DAF
THICKENER
TO YPS
12
32
— —#2-
THWASICKENED
PUMP
INTERMEDIATE
DEGRITTER
NO. 2
INTERMEDIATE
CRIT PUMPS
SCUM TO YPS
NO. 1
CHLORINE
CONTACT
TANKS
NO. 2
RAS
PUMPING
STATION A
� I
NO. 1
N0. 3
NO. 4
t29
DI DI
AERATION BASIN
101
WAS PUMP
SCUM PUMP
SCUM PI
SCUM P
N
SECONDARY
CLARIFIER
NO. 1
SECONDARY
CLARIFIER
NO. 2
ha(
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
D. NETT
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
THIS UNE IS ONE NCH WHEN
DRAWING S FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
0
0
m
0
z
EXISTING SOLIDS
PROCESS
SCHEMATIC
Figure Number
5-2
C
B
A
6
5
4
3
EXISTING
DESIGN CRITERIA CONDITIONS
TRICKLING FILTER
NUMBER 2
DIAMETER, Ft, EACH 170
MEDIA DEPTH, FT, EACH 8
WETTING RATE, GPD/SF, EACH
ANNUAL AVERAGE 392
MAXIMUM MONTH 562
MAXIMUM DAY 630
PEAK HOUR 705
INTERMEDIATE DEGRITTER
NUMBER 1
TYPE RECTANGULAR WITH SCREW GRIT CONVEYERS
SURFACE DIMENSIONS, FT, EACH 19 x 26.5
SIDEWATER DEPTH, FT
ANNUAL AVERAGE 7.8
MAXIMUM MONTH 8.0
MAXIMUM DAY 8.0
PEAK HOUR 8.1
DETENTION TIME, MIN
ANNUAL AVERAGE 2.4
MAXIMUM MONTH 1.7
MAXIMUM DAY 1.5
PEAK HOUR 1 4
OVERFLOW RATE, GPD/SF
ANNUAL AVERAGE 35,353
MAXIMUM MONTH 50.645
MAXIMUM DAY 56.802
PEAK HOUR 63,555
TRICKLING FILTER CLARIFIER
NUMBER 1
DIAMETER. FT 170
SIDEWATER DEPTH, FT 8
DETENTION TIME, HR
ANNUAL AVERAGE 1.8
MAXIMUM MONTH 1.3
MAXNUMBER
PEAK HOUR UM Y 1.0
OVERFLOW RATE, GPD/SF
MAXM MANNUAL
AMONTHE 1,123
MAXIMUM DAY 1,260
PEAK HOUR 1.410
AERATION BASIN
NUMBER 4
TYPE, EACH COMPLETE MIX
SURFACE DIMENSIONS, FT, EACH 60 x 90
SIDEWATER DEPTH, FT, EACH 26
VOLUME, TOTAL, 1,000 GAL x.201
DETENTION TIME. HR, EACH (INCLUDES 50% RETURN ACTIVATED SOLIDS)
ANNUAL AVERAGE 3.8
MAXIMUM MONTH 2.6
MAXIMUM DAY 2.4
PEAK HOUR 2.1
MIXED UQUOR SUSPENDED SOUDS, MG/L 1,900CAPACITY,
MIXED UQUOR VOLATILE SUSPENDED SOLIDS, MG/L 1,500
LB. BOD/LB. MLVSS
ANNUAL AVERAGE 0.32
MAXIMUM MONTH 0.56
MAXIMUM DAY 0.89
LB. BOD/LB. MLVSS
ANNUAL AVERAGE 0.39
MAXIMUM MONTH 0.68
MAXIMUM DAY 1.09
BLOWER
NUMBER 4
TYPE, EACH MULTISTAGE POSITIVE DISPLACEMENT
CAPACITY, ICFM, EACH 4.800
HORSEPOWER. EACH 400
RETURN ACTIVATED SOLIDS PUMP
NUMBER 2
TYPE, EACH SCREW
CAPACITY, GPM. EACH 13,500
HORSEPOWER, EACH 40
DRIVE TYPE, EACH CONSTANT SPEED
CHLORINE FLASH MIXER
NUMBER 1
HORSEPOWER 15
VOLUME, GAL 13,470
DETENTION TIME, MIN
ANNUAL AVERAGE 1.1
MAXIMUM MONTH 0.8
MAXIMUM DAY 0.7
PEAK HOUR 0.6
FINAL CLARIFIER
NUMBER 2
TYPE, EACH CENTER FEED, CIRCULAR
DIAMETER. FT, EACH 140
SIDEWATER DEPTH, FT 15
DETENTION TIME. HR. EACH (INCLUDES 50% RETURN ACTIVATED SOLIDS)
ANNUAL AVERAGE 3.1
MAXIMUM MONTH 2.2
MAXIMUM DAY 1.9
PEAK HOUR 1 7
OVERFLOW RATE, GPD/SF. EACH (INCLUDES 50% RETURN ACTIVATED SOLIDS)
ANNUAL AVERAGE 867
MAXIMUM MONTH 1,242
DAY PEAK HOUR 1,559 1,393
SOUDS LOADING, PPD/SF, EACH (BASED ON 50% RETURNED
ACTIVATED SOLIDS AND 1,900 MG/L MLSS)
ANNUAL AVERAGE 13.8
MAXIMUM MONTH 19 7
MAXIMUM DAY 22.1
CHLORINE CONTACT CHAMBER
NUMBER 2
LENGTH, FT. EACH 120
WIDTH, FT, EACH 30
SIDEWATER DEPTH, FT, EACH 15
VOLUME, TOTAL. 1,000 GAL 1,042
DETENTION TIME, TOTAL. MIN
ANNUAL AVERAGE 84
MAXIMUM MONTH 59
MAXIMUM DAY 52
PEAK HOUR 47
CHLORINATION EQUIPMENT
CHLORINATORS, NUMBER 3
CAPACITY, LB/DAY, EACH 1 0 500
2 0 2,000
CYUNDER SIZE, LBS 2.000
CYUNDERS, ACTIVE 3
CYUNDERS, STANDBY 3
AVERAGE DAILY CHLORINATION DEMAND, LBS 200 TO 300
DECHLORINATION EQUIPMENT
SULFONATORS, NUMBER 2
CAPACITY, LB/DAY, EACH 475
CYLINDER SIZE, LBS 2,000
CYUNDERS, ACTIVE 2
CYUNDERS. STANDBY 2
AVERAGE DAILY SULPHUR DIOXIDE DEMAND. LBS 40 TO 50
SOLIDS PROCESS SUMMARY
•
CENTRIFUGE
NUMBER 2 HDR Engineering, Inc.
CAPACITY, GPM 1 ® 80
CAPACITY. GPM 1 0 270illUIP
PRIMARY DIGESTER
NUMBER 3
41111
TYPE, EACH ANAEROBIC CfTY OF YAKIMA
DIAMETER. FT 1 0 70
FLOW, MGD
ANNUAL AVERAGE 11.3
MAXIMUM MONTH 15.3
MAXIMUM DAY 18.5
PEAK HOUR 24.0
BODS LOADINGS
ANNUAL AVERAGE
LOAD, LB/DAY 19,500
CONCENTRATION, MG/L 207
MAXIMUM MONTHMAXIMUM
LOAD, LB/DAY 23,200
CONCENTRATION, MG/L 260
MAXIMUM DAY
LOAD, LB/DAY 38,200
CONCENTRATION, MG/L 365
SUSPENDED SOLIDS LOADING
ANNUAL AVERAGE
LOAD, LB/DAY 17,800
CONCENTRATION, MG/L 190
MAXIMUM MONTH
LOAD. LB/DAY 20,100
CONCENTRATION, MG/L 230
MAXIMUM DAY
LOAD, LB/DAY 60,600
CONCENTRATION. MG/L 583
LIQUID PROCESS SUMMARY
2 O 45
SIDEWATER DEPTH, FT 1 0 32
2 0 30.5
VOLUME, TOTAL, 1,000 CF 220
VOLATILE SOUDS LOADING, LB/DAY/1,000 CF 120
SECONDARY DIGESTER
NUMBER 3
TYPE. EACH ANAEROBIC
DIAMEILR, FT, EACH 40
SIDEWATER DEPTH, FT, EACH 23
VOLUME. TOTAL, 1,000 CF 87
GASHOLDER COVERS
NUMBER
YAKIMA REGIONAL
WASLEWATER TREATMENT
FACILRY
WASTEWATER
FACILITIES
PLAN
3
TYPE FLEXIBLE MEMBRANE
DIAMETER, FT 40
Project Manager
A. KRUTSCH
GAS STORAGE VOLUME, CF, EACH 14,500
SOLIDS
Designed
D. NETT
DRYING BED
NUMBER 22
SURFACE
Drawn
E. MCDERMOTT
DIMENSIONS, FT, EACH 31 x 69
SUPERNATANT POND
Checked
MECHANICAL BAR SCREEN
2
WIDTH. FT, EACH 3
SCREENINGS COMPACTOR
NUMBER 2
SCREW DIAMETER, IN, EACH 7.38
CAPACITY, F73/HR, EACH 35
HORSEPOWER, EACH 1.5
VORTEX DEGRITTER
NUMBER 2
TYPE, EACH CIRCULAR
SURFACE DIMENSIONS, FT, EACH 16 DIA
SIDEWATER DEPTH, FT, EACH
ANNUAL AVERAGE 41g
PEAK HOUR 4.56
OVERFLOW RATE, GPD/SF, EACH
ANNUAL AVERAGE 44,300
PEA( HOUR 79,600
PARSHALL FLUME
NUMBER 2
THROAT WIDTH, FT, EACH 4
PRIMARY CLARIFIER
NUMBER 4
TYPE. EACH ROUND WITH CIRCULAR MECHANISM
DWAETER, FT, EACH 90
SIDEWATER DEPTH, FT, EACH 8
DETENTION TIME, HR, EACH
ANNUAL AVERAGE 2.1
MAXIMUM D 1 4
MAXIMUM DAYAY 1.3
PEN< HOUR 1 1
RATE, GPD/SF, EACH
ANNUAL AVERAGE 700
MAXIMUM MONTH 1,002
MAXIMUM DAY 1,124
PEAK HOUR 1.258
TRICKLING FILTER PUMP
NUMBER 4
TYPE SUBMERSIBLE, NON -CLOG CENTRIFUGAL
CAPACITY. GPM, EACH 8,400
HORSEPOWER, EACH 100
DRIVE TYPE, EACH CONSTANT SPEED
NUMBER 2
BOTTOM DIMENSIONS, FT, EACH 157 x 407
Project Number
06539-035-002
SIDE SLOPE, EACH 3:1
SIDEWATER DEPTH, Fr, EACH 15
Date
FEBRUARY 2000
VOLUME, TOTAL, 1,000 GAL 20,643
AIR EMISSION, SCRUBBERS
NUMBER 2
TYPE. EACH VERTICAL PACKED TOWER
VESSEL DIAMETER, FT, EACH 9
TREATMENT BED DEPTH, FT 10
CAPACRY, CFM, EACH 24,000
R U D K I N ROAD PUMPING STATION
I
ANNUAL AVERAGE, GPM 2,230
PEAK HOUR, GPM 5,400
NUMBER OF PUMPS 4
I
THIS LINE IS ONE INCH WHEN
DRAWING IS FULL S ZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
GRIT PUMP
NUMBER 2
TYPE CENTRIFUGAL
GPM, EACH 200
HORSEPOWER, EACH 15
DRIVE TYPE, EACH FIXED SPEED
GRIT CYCLONE AND CLASSIFIER
NUMBER 2
CLASSIFIER TYPE SCREW
CAPACITY, GPM, EACH 205
HORSEPOWER, EACH 3/4
DRIVE TYPE. EACH FIXED SPEED
PRIMARY SOLIDS AND SCUM PUMP
NUMBER 6
TYPE, EACH AIR OPERATED DIAPHRAGM
CAPACITY, GPM, EACH 150
WAS
AND SECONDARY SCUM PUMP
NUMBER 2
SCUM TYPE. EACH AIR OPERATED DIAPHRAGM
CAPACITY, GPM, EACH 150
NUMBER 2
WAS TYPE, EACH CENTRIFUGAL
CAPACITY, GPM. EACH 800
HORSEPOWER, EACH 10
DRIVE TYPE, EACH VARIABLE SPEED
DISSOLVED AIR FLOTATION
NUMBER 1
TYPE CIRCULAR
DIAMETER. FT 45
SIDEWATER DEPTH, FT 10
SOUDS LOADING, LB/HR/SF 1.0
TYPE, EACH SUBMERSIBLE, NON -CLOG, CENTRIFUGAL
CAPACITY, GPM 2 0 1,200
2 0 2,700
HORSEPOWER 2 0 35
0
2 0 77
DRIVE TYPE, EACH VARIABLE FREQUENCY
Description
m
a
Z
EXISTING PROCESS
DESIGN SUMMARY
Figure Number
5-3
c
B
A
Eg
ZFA
3 �S
6
5
4
3
2
1
WEIR
1009.35
1005.12
1008.20
1015
1010
1005
1007.60
1006.76
100712 100712
1006.71 1006.71
1005.27
1005.24
1002.36 1001.88
1001.47 1001.35
HEADWORKS
BUILDING W/
100° BAR SCREEN
995
1006.39
1005.59
990
1005.80
\ / PARSHALL
FLUME
VORTEX
DEGRITTER
985
LEGEND
PEAK FLOW 0 32 MGO (100 YR RIVER ELEV)
AVERAGE FLOW 0 17.8 MGD (NORMAL RIVER ELEV)
1001.79 1001.71
1001.33 1001.30
1005
1001.65 1001.71
1001.27 1001.30
PRIMARY
CLARIFIER
DISTRIBUTION
STRUCTURE
PRIMARY
CLARIFIER
PRIMARY
CLARIFIER
EFFLUENT
BOX
1003.24
1002.87
WEIR
1002.25
1003.11
1002.83
1002.28 1001.93
1001 48
1001.38
1015
1010
TRICKLING FILTERS
1005
1000
INTERMEDIATE TRICKLING
DEGRITTER FILTER
995
990
NOTES:
AVERAGE FLOW 0 50% RETURN
PEAK FLOW 0 335 RETURN
ALL PROCESS UNITS IN OPERATION
WEIR
1001.00
1001.13
1001.10
TRICKLING
FILTER
PUMPING
STATION
PUMPNG
STATION
JUNCTION BOX
985
1000.07 999.41 999.24
999.02
998.81
998.78
WEIR
998.50±
999.20
997.00
WAR
996.00
999.00 998.87
996.94 996.89
998.76
989.28
1000
995
990
985
980
975
AERATION BASIN
FINAL
CLARIFIER
SECONDARY
EFFLUENT
STRUCTURE
CHLORINE
MIXING
CHAMBER
1005
1000
CHLORINE
CONTACT
TANK
OUTFALL
100 YR RIVER
EL. 998.50
995
990
NORMAL RIVER
EL. 988.60
985
CONNECTION
BOX
OUTFALL
STRUCTURE
980
975
HYDRAULIC PROFILE
HDR Engineering. Inc.
CRY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACIUTY
WASTEWATER
FACILITIES
PLAN
Project Manager
A KRUTSCH
Designed
D. NETT
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
DRAWING S FULL SIZE IF NOT
ONE INCH. SCALE ACCORDINGLY.
e
0
0
co
,73
z
EXISTING
HYDRAULIC
PROFILE
Figure Number
5-4
•
DRAFT
A steady state model of the treatment plant was constructed. This model was used to predict the
loading to the treatment plant unit processes. The process loadings to the individual major unit
processes were calculated for the three different conditions: annual average, maximum monthly,
and maximum daily conditions (March, August, and October/November), and peak hour using
current process unit sizing. The size and type of each process unit are summarized in the Design
Criteria in Figure 5-3.
After the process model was constructed, loading conditions were compared to standard and site
specific recommended process loading limits and design criteria. For example, once the primary
clarifier flows and loadings were determined from the mass balance, they could then be
compared to industry, State Standard, and HDR standard criteria. This comparison allows one to
determine whether the unit process (in this case the primary clarifiers) are under- or over -loaded
compared to recognized criteria. Unit process capacity assessments are based on the flow
increase that can be accommodated by the existing unit processes under current influent and
operating conditions.
The treatment capacity of the process unit was determined as a ratio of the current to the
allowable loading as shown in Table 5-4. For example, the primary clarifier annual average
overflow rate is currently 477 gpd/sf. The allowable overflow rate is 1,200 gpd/sf based on
Washington State Standard Design Criteria requirements. The current annual average flow to the
plant is 11.97 mgd. Therefore, the treatment capacity of the primaries to maintain the overflow
rate below 1,200 gpd/sf is 30.1 mgd (11.97*1,200/477 mgd).
• The values in Table 5-4 show the capacity of the major process treatment units under the
condition stated. For example, the primary clarifiers have two criteria:
•
➢ To maintain the average overflow rate under 1,200 gpd/sf, the maximum annual average
flow is 30.1 mgd.
➢ To maintain the peak overflow rate below 2,500 gpd/sf, the maximum peak flow is 63.4
mgd.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
PAGE 8
•
DRAFT
Table 5-4. Rated Capacity (mgd) of Unit Processes under various Operating
Criteria.
Unit Proc
Parameter Condition Limit Unit Annual March August Oct Peak
Primary Clarifiers OFR Avg 1200 Gpd/sf 30 1
Primary Clarifiers OFR PH 2500 Gpd/sf
Trickling Filters OLR Avg 50 lb/kcf/d 13.5
Trickling Filters OLR MM 65 lb/kcf/d 13 7 26.0 13.8
Aeration Basins MLSS MM 2200 Mg/L 12.1 22.4 12.3
Aeration System OUR MD 52 Mg/L/h 20.4 36.6 24.8
Aeration System OUR MM 52 Mg/L/h 23 4 44.0 28.3
Secondary Clarifiers HRT PH 2 Hr
Secondary Clarifiers OFR Avg 600 Gpd/sf 18.0
Secondary Clarifiers OFR PH 1200 Gpd/sf
Secondary Clarifiers SLR Avg 24 Lb/d/sf 18.9
Secondary Clarifiers SLR MM 30 Lb/d/sf 23.5 23 9 23.5
Secondary Clarifiers SLR MD 36 lb/d/sf 28.3 28.7 28.5
Chlorine Contact Basins HRT Avg 60 min 18.9
Chlorine Contact Basins HRT PH 20 min
DAF Thickeners SLR Avg 20 lb/d/sf 57.4
DAF Thickeners SLR MM 20 lb/d/sf 44.2 95 9 44.8
Anaerobic Digester' HRT MM 15 d 21.3 41 4 22.3
Digested Biosolids Holding Tank' HRT MM 4 d 29 6 57 7 31.1
Centrifuge2 Flow MM 270 gpm 41.3 23 4 43.5
63 4
31 4
36.5
57 4
Avg = Annual average condition
MM = Maximum month condition (applies to March, August, and October)
MD = Maximum day conditions
PH = Peak hour conditions
HRT = Hydraulic retention time
SLR = Solids loading rate
Flow = Flow
OFR = Overflow rate
OLR = Organic loading rate
OUR = Oxygen uptake rate (aeration system limitations)
1 For the Anaerobic Digesters and Digested Biosolids Holding Tanks (Secondary Digesters), the figures indicate days of
hydraulic retention time for the solids loadings anticipated during the periods shown.
2. For the centrifuge, the figures indicate hours of operation to process digested solids for one week during the period shown at
a dewatering rate of 270 gpm.
In some cases, there are multiple capacity limits that apply. For example, the trickling filter or
activated sludge processes are controlled by the maximum month loading rates and have a
capacity associated with each of the months analyzed. Table 5-4 does not select the most
restrictive condition.
One of the criteria controls the overall capacity and size requirements. Selection of the
controlling criteria is completed by normalizing the flows to an "equivalent dry weather flow", or
other referenced condition.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
PAGE 9
•
•
DRAFT
The results in Table 5-4 show the following:
➢ Peak flow capacity is limited to 31.4 mgd, or 131 percent of current peak flow, based on
secondary clarifier capacity with aeration basin operation in other than plug flow mode.
➢ For the analysis conducted, where various critical months are considered, the annual
average condition has tittle meaning. As long as the treatment facilities can handle the
various peak month conditions, the plant will operate satisfactorily. As plant
improvements are made in the future, hydraulic limitations (pipelines) that currently exist
between unit processes will need to be evaluated.
➢ The maximum capacity in March is limited by the aeration basin capacity to 12.1 mgd
(129 percent of the present March flow of 9.4 mgd). The 12.1 mgd capacity is the limit
based on a MLSS concentration of 2200 mg/L. If the MLSS is increased to sustain the
sludge age, the trickling filters become the limiting process at 13.7 mgd. The load to the
trickling filter can be reduced by bypassing some flow and sending it directly to the
activated sludge. This mode of operation will further increase the activated sludge
loading. A balance is expected at about 15-16 mgd.
➢ The maximum capacity in August is limited by the aeration basin capacity to 22.4 mgd
(156 percent of the present August flow of 15.25 mgd). Similar to the March condition,
the 22.4 mgd capacity is the limit based on a MLSS concentration of 2200 mg/L. If the
MLSS is increased to sustain the sludge age, the trickling filters become the limiting
process at 26.0 mgd. The load to the trickling filter can be reduced by bypassing some
flow and sending it directly to the activated sludge process. This mode of operation will
further increase the activated sludge loading. A balance is expected at about 28-30 mgd.
➢ The maximum capacity in October -November is limited by the aeration basin capacity to
12.3 mgd (120 percent of the present flow of 10.27 mgd). Similar to the March
condition, the 12.3 mgd capacity is the limit based on a MLSS concentration of 2200
mg/L. If the MLSS is increased to sustain the sludge age, the trickling filters become the
limiting process at 13.8 mgd. Again, the load to the trickling filter can be reduced by
bypassing some flow and sending it directly to the activated sludge process. This mode
of operation will further increase the activated sludge loading. A balance is expected at
about 15-16 mgd.
➢ The maximum day loading is determined by the aeration capacity in March (20.4 mgd or
185 percent of current flow) and November (24.8 mgd or 198 percent of current flow),
and secondary clarifiers in August (28.7 mgd or 188 percent of current flow).
Based upon the estimated capacities presented in Table 5-4, the limiting capacity was determined
for each of the critical flow conditions, and the resulting loading and operational limitations were
calculated as shown in Table 5-5 below.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
PAGE IO
•
•
DRAFT
Table 5-5. Summary of Capacity Limiting Processes.
March
August October -November
Monthly Loading — First Limiting Process:
Limiting process Aeration Basin Aeration Basin Aeration Basin
Limiting parameter MLSS MLSS MLSS
Capacity limit 12.1 22.4 12.3
Monthly Loading — Second Limiting Process:
Limiting process
Limiting parameter
Capacity limit
Maximum Day Loading:
Limiting process
Limiting parameter
Capacity limit
Trickling Filter
Organic Loading
137
Aeration Basin
Aeration System
20.4
Secondary Clarifier
Solids Loading Rate
23.9
Secondary Clarifier
Solids Loading Rate
28.7
Peak Hour Loading:
Limiting process Secondary Clarifier
Limiting parameter HRT
Capacity limit 31 4
Trickling Filter
Organic Loading
13.8
Aeration Basin
Aeration System
24 8
A process by process breakdown shows the following:
➢ Primary clarification. Not limited, process is at about 50-60 percent of capacity.
Adequate redundancy is provided to meet 2020 design conditions with one primary
clarifier out -of -service.
➢ Trickling Filters. At capacity. Bypass excess flow to remain under 65 lb/kcf/d loading.
The target loadings are relatively high and anticipate polishing in the downstream
activated sludge process. Changing media will provide some additional capacity. A
closer evaluation of the trickling filter capacity should be conducted to determine the
threshold limits.
> Activated Sludge. Near capacity for solids and may be aeration limited. Bypass flow set
to achieve maximum loading. Process limited by the solids loading based on the 2,200
mg/L MLSS. During peak day loading, the effective sludge age (to maintain about 2,200
mg/L) drops to about 5.5 days. While this is sufficient for a limited time (single day) this
low sludge age should not be maintained for an extended period. A higher MLSS will
give a higher sludge age with a larger safety factor to sustain nitrification. Field testing to
establish the oxygen transfer efficiency is recommended to refine the aeration capacity.
> Secondary Clarifiers. Nearing capacity at peak flow conditions when system reliability
is considered. At 75 percent of peak (August) month flow conditions with one clarifier
out of service, the overflow rate is 750 gpd/sf versus 800 gpd/sf. True capacity of the
secondary clarifiers should be determined in field tests to verify that the 800 gpd/sf
limitation is accurate.
➢ Chlorine Contact. The detention time is adequate under the average (17.94 mgd) and
peak flow conditions (38.01 mgd) for 2020 design projections. Maximum month average
daily flow of 22.78 mgd would reduce detention time to approximately 50 minutes versus
a required 60 minutes. Field testing should be conducted to determine actual detention
times.
> DAF thickeners. Not Limiting. System redundancy is not provided.
HDR ENGINEERING, INC. PAGE 11
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
•
DRAFT
➢ Anaerobic Digestion. About 30 percent excess capacity with all digesters in service.
System at capacity with Primary Digester 1 out of service during maximum month.
> Sludge holding. Not limiting.
> Dewatering. Not limiting based on the 270 gpm centrifuge. Only one 270 gpm Sharples
centrifuge is available with one 80 gpm Byrd centrifuge as backup. The Sharples
centrifuge is currently operated 30 to 35 hours per week to process all solids. With the
centrifuge capacity at 80 gpm, 24 h/d, 7d/w operation may be required to handle the
solids loading. An additional 270 gpm centrifuge will provide the required firm capacity
to meet future requirements and is recommended.
5.5 Process Unit Capacity Evaluation
The information provided in Tables 5-4 and 5-5, combined with the information provided by
operations staff in meetings conducted in December, 1998 and January, 1999, 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.
5.5.1 Preliminary Treatment
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'-0" X 7'-10" 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.
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 '/ 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.
Safety, Reliability and Staff Issues
➢ The building screenings area experiences a fly problem during the summer months.
Screens are presently installed at building openings. The screen openings may be too
large to prevent insects from entenng the building. Doorways are often opened at this
facility which also permits entry of flies and other insects.
> The compacted screenings discharge into an open dumpster in the screenings room.
Process Rating
• The mechanical bar screens have a combined peak hour hydraulic capacity of 40 mgd (20 mgd
per unit). The current peak hour flow of 24.0 mgd can be easily accommodated with the existing
HDR ENGINEERING, INC. PAGE 12
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
•
•
DRAFT
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 38.01 mgd in year
2020. Annual average flows for 2020 of 17.94 mgd are also below the capacity of one bar screen
providing sufficient redundancy to handle future annual average flows.
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.
Safety, Reliability and Staff Issues
D 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.
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. Grit is discharged to
a dumpster for truck haul to disposal at a landfill operation.
Safety, Reliability and Staff 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:
• The initial installation changed the gear box and drive for the vibratory system.
Cracking of welded joints has occurred at the vibratory unit connections.
• Old vibratory units were installed on a new tank during the last system upgrade.
• Operations staff would prefer to maintain a truck under the hopper during normal
operation to better control seepage and other discharge from hopper system dunng
storage cycles.
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 Influent Building, grit is conveyed
through two grit cyclone and screw classifiers. Each of these units has a capacity of 205 gpm and
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
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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.
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.
Safety, Reliability and Staff 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 is 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 gnt loading.
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 gnt
basins. Ultrasonic level measuring and transmitter devices installed at each flume provide flow
measurement.
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.
5.5.2 Primary Treatment
Flow Split
Wastewater flows from the Parshall flumes through channels and into the pnmary 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
Pnmary Clanfier influent pipes controlled with sluice gates. Manual regulation of the sluice gate
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
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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.
Safety, Reliability and Staff 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 pnmary influent pipeline for measurement of
the flow split.
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 maintain basin detention time to 1.0 to 2.0 hours.
Typically, two clarifiers are placed in operation to handle current flow conditions.
• Safety, Reliability and Staff 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.
> 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 pnmary clarifiers are a reported problem.
Process Rating
The loading to the pnmary clarifiers is relatively low. Under annual average conditions, the
pnmary overflow rate is only 445 gpd/sf when all basins are in-service, compared to a design
value of 800 to 1200 gpd/sf recommended by WDOE Criteria. Even under peak hour loading
conditions the overflow rate is currently only 1,249 gpd/sf, well below the WDOE Criteria of
2,000 to 3,000 gpd/sf. The maximum hydraulic retention time recommended by WDOE is 2.5
hours. HDR recommends a minimum 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 cntena controls the capacity. The rated capacity of
the pnmary clarifiers is 30.1 mgd during maximum month average daily flow conditions, or 63.4
mgd under peak hour flow conditions.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
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The reliability standards 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. Because 4
primary clarifiers are available, Yakima meets this redundancy criteria without difficulty.
Primary Sludge Pumping
Sludge and scum are withdrawn through six air -diaphragm (ODS) pumps located in the Sludge
Transfer Building, each with a fresh -water capacity of 150 gpm. 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, primary sludge concentration, and sludge pH frequently to determine pumping rates.
Combined solids concentration of the pnmary sludge is typically maintained at 5 to 6 percent.
Safety, Reliability and Staff Issues
➢ Thickening in the clarifiers to greater than 6 percent solids concentrations is problematic
for downstream processes.
➢ 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. 1 stroke every 20/30/40/50
seconds). One pump is allowed to operate at a time.
➢ Access to the piping valve trench in the primary sludge pumping building is difficult.
Better lighting and/or replacement of the access cover with a new light cover system is
desired.
Process Rating
The primary sludge and scum pumps are arranged for 100 percent redundancy of pumping units,
meet minimum requirements for pumping of the solids at the current loading rates, and provide
for the minimum 2 fps scouring velocity in the pipelines as required by the WDOE design
criteria.
Primary Scum Pits
Two 4'-0" 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 Pnmary
Clarifiers Nos. 2 and 3. The North pit also collects scum from the telescoping scum removal
valves in the primary influent split box.
Safety, Reliability and Staff 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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
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Sludge Transfer Building
The sludge transfer building is centrally located between the four Pnmary Clarifiers. It houses
the four air -diaphragm sludge pumps, 2 air -diaphragm scum pumps, and 1 dewatenng pump 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.
Safety, Reliability and Staff 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. The flows do not receive appropriate primary treatment. The
location of the sump discharge should to be relocated.
5.5.3 Secondary Treatment
5.5.3.1 Trickling Filter System
Flow Split
Primary effluent and food processing waste flows enter the west 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 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. Normal mode of operation is to establish a base flow directed to the activated
sludge system with all remaining flows being forced to pass through the trickling filters prior to
introduction to the activated sludge process. The wetwell level in the pumping station is
controlled by a modulating sluice gate that controls the re -circulation flow back to the pumping
station by controlling the amount of re -circulated flow allowed to go to the aeration basins or
back to the trickling filter wet -well. The trickling filter clarifier is not typically utilized.
Safety, Reliability and Staff Issues
➢ The recirculation flow control sluice gate motor experiences considerable modulation
throughout the year. The lift nut on the gate electric operator is typically replaced at least
once per year. There are concerns with reliability of the flow split to the aeration basins
because the only control available is through the control valve.
Trickling Filter Pumping Station
The Trickling Filter Pumping Station is located adjacent to the primary effluent flow split
structure. Four submersible non -clog centnfugal pumps are used to force flow to the North and
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
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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.
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. The
two trickling filters can only be operated in parallel, and it is not possible to segregate the
effluent flow of one unit from 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.
Trickling Filters
Two 170 -foot diameter Tnckling 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 tnckling filters. Each filter contains 8 -foot of rock media.
Safety, Reliability and Staff Issues
➢ A snail problem exists in the filters, and a intermediate degritter facility was installed to
mitigate the effects of snails on downstream processes.
➢ Currently, the rotational speed of the filter distributors can only be minimally controlled.
➢ The trickling filter center drive mechanisms are getting water (condensation) in the gear
oil.
➢ The filter media appears to be plugging around the outside perimeter of the trickling
filters.
➢ Water and ice are falling off the tnckling filter dome covers, above access doors, and
around the air emission blowers.
➢ Ice sometimes builds up and water accumulates around the intermediate degntter near the
access to stairs.
Process Rating
Under current operations, two recirculation pumps are operated with each pump dedicated to an
associated trickling filter. The total recirculation rate is approximately 27.4 mgd. Maximum
capacity for the trickling filters for cntical months of March, August and October/November are
13.7, 26.1 and 13.8 mgd respectively. These numbers anticipate that all pnmary effluent flow is
routed to the trickling filters. Some flow is routed to the aeration basins to provide sufficient
nutrients to maintain the biomass in the basins. Should the capacity limit of the trickling filters
be reached before the activated sludge system, additional flow can be routed around the tnckling
filters directly to the activated sludge system. The maximum capacity of the trickling filter
system is directly impacted by the capacity available in the activated sludge process.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
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Intermediate Degritters
Trickling Filter effluent passes through intermediate degritters, each fitted with two rectangular
screw grit conveyors. Flows pass through the degritters prior to returning to the tnckling filter
pumping station wet well. Surface dimensions of the degritter chambers are 18'-10" X 26'-6"
each equaling 4,025 cf per basin. The chambers are designed to remove snails from the tnckling
filter effluent. Although not the standard mode of operation, the effluent may also bypass the
degritters to discharge directly to the Secondary Effluent Flow Diversion Box.
Safety, Reliability and Staff 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.
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 pumps 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 detention times within
grit removal facilities be in the range of 3 to 5 minutes. Although the peak design flow of the
pumping station at 36.0 mgd is slightly in excess of this criteria, the peak loading on the trickling
filters at maximum month conditions is anticipated to be 26.1 mgd. At this peak flow/loading
rate, a detention time of 3.3 minutes is provided. This is within the minimum guidelines
recommended by WDOE design criteria.
Trickling Filter Clarifier
Trickling filter effluent may be transferred to a 170 -foot diameter Trickling Filter Clarifier with
an 8 -foot side water depth. Although the clarifier is not utilized as part of standard operations, it
can perform trickling filter slough removal prior to entering the activated sludge process. This
clarifier is not provided with sludge drawoff pipes on the clanfier mechanism. Solids are
removed from the clarifier using the intermediate degritter pumping station grit pumps. Manual
operation of valving within the pumping station is required for solids removal.
Safety, Reliability and Staff Issues
➢ The gate in the secondary effluent diversion manhole leaks. Whenever operations staff
use the trickling filter clarifier, sewage leaks through the gate and contaminates sample
locations downstream at the outfall connection box. The leaking gate needs to be blocked
off or replaced.
➢ The slide gate in the secondary effluent diversion box that directs flow to the trickling
filter clarifier leaks.
➢ Solids removal from the basin is cumbersome. Valves within the intermediate degntter
station need to be manually changed when pumping is needed. The intermediate degritter
air operated diaphragm grit pumps are used. All pumping is manual operation and
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
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pumping redundancy with the degntter operations is impacted when sludge pumping is in
operation.
➢ Dewatering pumps are needed for this facility.
Process Rating
The trickling filter clarifier is not generally operated. 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. Under these hydraulic loading
conditions the clarifier capacity would be 13.6, 18.1 and 27.2 mgd respectively.
5.5.3.2 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 filters 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 aeration, 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 may exit from any or all
of the aeration basins, depending upon mode of operation.
Aeration Basins/Low Pressure Air
Each of the four aeration basins have surface dimensions of 60 -feet X 90 -feet and a 26 -foot
sidewater depth. The combined Aeration Basin volume is 4,201,000 gallons. 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. Expenence has
shown that it is very 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 senes with the flow
passing from basin to basin until exiting into the mixed liquor channel from the final basin. The
plug flow mode is used extensively and provides good results. The return sludge mixes with the
influent in the first basin.
Under step feed mode of operation, wastewater is distributed evenly to all basins. Plant
operations have not experienced success with this mode of operation.
Under contact stabilization mode of operation, influent wastewater is first mixed for 30-90
minutes with the activated sludge in a basin designated as the contact basin. 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
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
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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, 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. 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.
Safety, Reliability and Staff 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.
➢ The normal mode of operation is to operate under the plug flow mode. Aeration basin
No. 4 has expenenced a failure to the basin slab. As a result, aeration basin No. 4 is not
operated and three basins are used for the plug flow mode.
➢ 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 degntting facility. Snails are getting
through to the aeration basins and are settling to the bottom of the aeration basins.
➢ The current fine bubble diffuser system uses ceramic diffuser plates. Cleaning is a
problem (use of acid for cleaning).
➢ The air metenng systems do not record air flow.
➢ The variable frequency drives for the blowers (Siemens) are older technology units and
require added maintenance. Control cards require frequent replacement. Problems exist
with isolation transformers and filters tripping out.
➢ City staff have had difficulty maintaining the four (Gardner/Denver) blowers in operation.
The units require a significant amount of maintenance and staff finds they are typically
working on at least one unit.
➢ When in the AUTO mode of operation, the blowers cycle. Operation staff adjust 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. The Operations staff
have not monitored this occurrence in the secondary clarifiers.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
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Process Rating
The activated sludge process at Yakima operates in the plug flow mode with up to three basins
available for operation. This capacity evaluation anticipates that the trickling filter process
would be discontinued, and that the activated sludge process would operate at a sludge age of 7-8
days, with the solids loading limit of 2,200 mg/L. Operations staff have experienced problems
with process upset at MLSS values in excess of this amount. During current peak day loading,
the effective sludge age (to maintain no more than about 2,200 mg/L MLSS) drops to 5.5 days.
Although sufficient for a limited time (single day), this low sludge age should not be maintained
for an extended period of time.
Current process loading evaluation indicates that the aeration basins are nearing capacity for
solids loading at a MLSS of 2,200 and maximum month loading condition. The maximum
capacity in March, when influent loading is higher, of the aeration basins is 12.1 mgd. Dunng
the month of August when loadings are generally lower (even though flows are at high levels),
the aeration basin capacity is 22.4 mgd. The maximum capacity of the aeration basins during the
October -November critical design period is 12.3 mgd. This capacity rating is based on all
aeration basins in-service, sufficient air supply is provided, and an oxygen uptake rate (OUR) of
52 mg/Lfh is achievable. Based upon earlier aeration system evaluations, the aeration system
will be limited in capacity.
Facility reliability is a key issue with the activated sludge system. The WDOE design standards
require the activated sludge basins and aeration system be able to meet the influent demands with
the largest process unit out of service. With aeration basin No. 4 currently out of service,
aeration basin capacities are 75 percent of that noted above, indicating the plant is operating near
capacity at current flow and loading conditions with a MLSS concentration of 2200 mg/L. There
are problems with the maintenance of the aeration blowers and blower VFDs which typically
leave one unit out of service.
Flow and loadings are approaching the current aeration basin capacity limit if the tnckling filter
process were to be discontinued. During the October -November critical design month,
approximately 20 percent reserve capacity is available, provided aeration basin No. 4 is available
for service. Based upon the projected population increase presented in Section 3 and Section 4,
the aeration basin capacity will be exceeded in 2005 if the trickling filter process is discontinued.
Section 5.4 includes a discussion regarding the combined capacity of the trickling filter and
activated sludge process.
Secondary Clarifiers
Mixed liquor exits the Aeration Basins into two 140 -foot circular Secondary Clarifiers. Each
clanfier operates at a 15 -foot sidewater depth. Wastewater enters the clarifiers through a center
feed well and overflows into an inboard (interior) launder.
Process Rating
The overflow rate (OFR) of the secondary clarifiers is presently at 390 gpd/sf under average flow
conditions, or 1,030 gpd/sf under peak hour flow conditions. This is well within the WDOE
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CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
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design cntena of 600-800 gpd/sf for average conditions and 1,200 gpd/sf for peak flow
conditions.
The reliability standards for WDOE require that the final sedimentation system be able to handle
75 percent of the design flows with one unit off-line. 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 11.28 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 a peak hour flow of 24.6 mgd. Current peak
hour flow is 24.03 mgd.
Based upon the above, the secondary clarifiers are currently at or near hydraulic capacity.
Evaluation of the secondary clarifiers for solids loading rate (SLR) indicate solids loading of the
clarifiers is not the limiting criteria. Based upon an SLR of 24 lb/d/sf for average conditions and
36 lb/d/sf for maximum day conditions, the capacity of the clarifiers is 18.9 and 28.3 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. Based upon the increase in flows and loads projected in Section 4, additional
secondary clarifier capacity is needed prior to year 2005 to meet WDOE redundancy cntena.
IIISafety, Reliability and Staff Issues
•
> Cleaning the secondary clarifiers remains a problem. Chlonne control systems installed
along the launders require additional improvement.
> The baffles on the secondary clarifiers collect solids (accumulating algae) which is
difficult to remove.
> The inboard launders are suspected to impact secondary clarifier performance. Need to
look into moving the launders out to the outside edge of the basins.
> Secondary clarifier bull -gears:
• grit was found in the gear housings.
• 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 secondary scum boxes are too small and should be enlarged.
> Location of any new secondary clarifiers on-site will be a major issue.
• Impact on existing power lines.
• Flow split to existing and new secondary clarifiers will be difficult.
• Impacts on solids lagoons needs to be evaluated when selecting a site for new
clarifiers.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER TREATMENT PLANT OCTOBER 6, 2000
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RAS
• 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.
•
Safety, Reliability and Staff Issues
➢ RAS Screw Pumps:
• An access manhole for maintenance of the lower bearings is needed.
• 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.
• The isolation gates for the screw pumps are in need of re -working.
• Spare parts for the screw pumps are not readily available.
• On one screw pump, a new gearbox is needed. Alternatively, the existing gearbox
should be completely re -built.
➢ 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 1 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.
Normal reliability standards would require 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 2020 of 17.94 mgd. The pumping facilities do not have sufficient capacity to handle the
peak hour condition of 38.01 mgd. Only a slight compromise in return rates is necessary to meet
this flow condition.
WAS and Secondary Scum Pumping
Waste activated sludge and secondary scum are pumped from the secondary clarifiers through
two separate pumping systems. WAS is pumped via two 10 HP, 800 gpm, variable speed, VFD
controlled centrifugal pumps. Secondary scum is pumped via 2 air -diaphragm pumps, each with
a freshwater capacity of 150 gpm. The air diaphragm pumps are also used for pumping clarifier
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bottom sludge periodically. Both systems may serve as redundant to each other. Magnetic flow
meters located on the discharge side of the centrifugal pumps set the secondary wasting,
controlled from either a speed control or time control mode of operation.
Safety, Reliability and Staff Issues
➢ The air diaphragm pumps are typically used for pumping bottom sludge and scum.
Designated suction piping and valves for bottom sludge and scum would be desirable.
5.5.4 Final Disinfection
Chlorination Mixing
Secondary effluent flows into the chlorine mixing chamber where chlorine solution is introduced
through a chlonne 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.
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 1,042,000 gallons at a sidewater
depth of 15 -feet with an estimated effective contact volume of 808,000 gallons. 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.
Chlorination Facilities
The chlorination building is located north of the chlorine contact chamber. The facility has three
rooms, including a chlorine storage room, chlorine 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 foul air control system.
Each chlorinator has an individual capacity of 500 lb/day. The facility maintains three active,
and three standby, 2000 pound chlonne 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.
Dechlorination Facilities
The Dechlorination Building is located directly north of the Chlonnation 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, foul air scrubber recirculation pumps, and the
chemical recirculation pumps. 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. SO2 is
injected into the plant effluent at the Chlorine Contact Chamber outlet pipe and samples are
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extracted from the Outfall Connection box. Normal usage of sulfur dioxide at the Yakima
110 Regional WWTP is 40 to 50 lbs/day.
Safety, Reliability and Staff 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
dechlonnation are a concern on the impacts to aquatic life.
> The chlonne cylinder scales have poor resolution, and weight information from them is
not very accurate. New scales are needed if chlorination is maintained as the process for
disinfection.
> Leakage in the slide gate at the secondary effluent flow diversion box is creating
problems with obtaining accurate/representative samples of the plant effluent. If all
sampling is performed at this structure, a building is needed over the structure.
Process Rating
With three active 2,0001b cylinders, the chlonnation 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 1000 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
18.9 mgd. At peak flow conditions, the estimated capacity of the chlorine contact is 57.4 mgd,
well in excess of design critena for peak flow conditions.
Based upon projected flows and loadings presented in Section 4, the contact channel has
sufficient capacity to the year 2020 average annual flow conditions of 17.94 mgd and year 2020
peak flow conditions of 38.01 mgd. During 2020 maximum month average daily flow conditions
of 22.78 mgd, detention time in the contact channels will only be 50 minutes, or less than the
recommended 60 minutes.
5.5.5 Outfall
Outlet Box
Treated and disinfected wastewater flows into an outfall connection box southeast of the trickling
filter clarifier. Trickhng filter clarifier effluent may be directed to the connection box and
combined with plant effluent. 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
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manual sluice gate as isolation. Effluent typically flows over the weir 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
into the nver at a 45 degree angle to river flow direction.
Safety, Reliability and Staff Issues
➢ Gate leakage and operation repairs are required at the outlet box.
Process Rating
The capacity of the existing outfall and outlet box facilities is estimated to be in excess of 45.0
mgd. 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 of 38.01 mgd for year 2020 if the Yakima river is not at the 100 year flood level.
5.5.6 Non -Potable Water System
Non -potable 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 500gpm at 145 TDH.
Pumped C2 water combines and enters the Chlorination Building where it flows through
automatic strainers then out to the plant system or chemical mixing. Two booster pumps,
operating at 60 gpm and 85 ft TDH with 3 HP motors, supply C2 to the chemical mixing and
feed systems.
Safety, Reliability and Staff 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 critena 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.
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5.5.7 Solids Thickening
Dissolved Air Flotation Thickener
Solids (WAS) from the secondary processes are directed to a single 45 -foot diameter dissolved
air flotation thickener (DAFT) for thickening. The DAFT and Solids Building are situated at the
west end of the aeration basins. A 10 -foot sidewater depth is maintained in the DAFT tank.
WAS is pumped from the Secondary Clarifiers and into the DAFT tank where air induced
recycled water is introduced. Thickened waste activated bottom solids and float solids are
removed from the DAFT with 2 air -diaphragm pumps. The Solids Building houses the recycle
pumps, TWAS pumps, saturation tank, and two air compressors that support the DAFT process.
Safety, Reliability and Staff Issues
D The DAFT unit has been reliable and not a significant source of maintenance to the staff.
D The support air compressors, that were originally installed in 1985, are in need of
replacement.
D 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.
D The DAFT tank cannot be drained completely with the drainage piping currently
installed.
D C2 should be located next to the DAFT to better enable washdown activities at the DAFT
unit.
D No system redundancy is provided with the DAFT system.
Process Rating
The solids loading rate (SLR) at the DAFT unit under average loading conditions is estimated at
3.9 lb/d/sf and 8.9 lb/d/sf under maximum month loading conditions. This is well below typical
design cntena of 18-24 lb/d/sf. The DAFT thickening system has the capacity to handle up to
31,800 lb/d of WAS, as compared to current WAS loads of 6,265 lb/d at average conditions and
14,161 lb/d at maximum day loading conditions.
Projected annual average and maximum day conditions for year 2020 are 9,706 lb/d and 21,938
lb/d. Sufficient capacity is available with the existing DAFT unit to meet year 2020 loading
conditions. No redundancy is provided with the DAFT system.
5.5.8 Solids Digestion
Primary Digesters
Two 45 -foot and one 70 -foot diameter anaerobic pnmary digesters are available for primary
digestion. The two smaller digesters contain a sidewater depth of 30.5 -feet and the larger unit
holds a 32 -foot depth. Total volume within the three digesters is 220,000 cubic feet or 1,646,000
gallons. The digesters are mixed with top entering turbine mixers. Digester heating to 98 to 100
degrees F is provided by associated recirculation pumps and hot water/sludge spiral heat
exchangers.
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• Safety, Reliability and Staff Issues
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➢ Operation of the top entering mixers is functioning properly.
➢ Flow meters on each recirculation line would be desirable for improved operation.
> Air locking on the recirculation system piping occurs, requiring operations staff to
manually bleed -off air.
➢ The hot water system mixing valve in the hot water loop at the boilers needs to be
reinstalled (i.e. run water through the spiral heat exchangers at a lower temperature).
There is some concern that this reinstallation will reduce the amount of heat available to
the primary complex. Careful evaluation of the heat system is needed in this area.
➢ The operation of the hot water heat loop at lower temperatures will prevent surging the
boilers.
> Scale is building in the hot water boilers because they are running too cold (i.e. flows
coming back are cold). The heat balance needs to be reevaluated.
➢ 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.
Process Rating
The primary digestion facilities provide about 37.7 days hydraulic retention time (HRT) under
current average loading conditions and 21.1 days under maximum month conditions. This falls
within the standard design criteria of 10-20 days for standard high rate mesophyllic systems
producing a Class B biosolids.
WDOE currently requires redundancy in digester capacity. This could be achieved by using the
secondary digestion/storage tanks on a temporary basis. These facilities are not heated and
mixing is limited. At current loading conditions, approximately 30 percent excess primary
digestion capacity remains with all digesters in operation.
Section 9 discusses future options for handling biosolids. As part of the evolution of future
facilities needs, additional digestion capacity and alteration of existing facilities to different
digestion strategies capable of producing Class A biosolids are considered.
Secondary Digesters (Storage Holding)
Three 40 -foot diameter Secondary Digesters are utilized typically as digester storage, but also
produce minor volatile solids reduction. These units have a sidewater depth of 23 -feet and hold
up to 87,000 cumulative cubic feet or 650,800 gallons of storage prior to dewatering. A flexible
membrane gasholder cover system is provided on all three secondary digesters. The gasholder
cover system is connected to the primary digestion gas system and enables all methane gas
produced in the entire digestion facility to be stored and reused as a heat source to the greatest
extent possible. The methane gas storage capacity will fluctuate based on stored solids.
Normally, the system methane gas storage is approximately 35,000 cubic feet. The system
incorporates heat exchangers and boilers to produce a heat source for the digesters and other
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facilities throughout the plant. A waste gas flare is available to thermally destruct all excess gas
produced from the system.
Safety, Reliability and Staff Issues
D Preheating the solids before centrifuge operations to determine if this may benefit solids
removal should be evaluated.
D The flexible membrane gasholder cover system is experiencing problems with
maintaining gas pressure within the system. It is suspected the pressurization blower
system is undersized for the application.
D Only a single recirculation pump is available to serve all three secondary digesters. It
would be desirable for each secondary digester to have its own dedicated recirculation
pump.
D The waste gas flare needs a new control valve. Operation currently complies with air
quality permitting.
D Piping connections could be added to the digester piping to allow for vactor truck
pumping of the digester contents via the piping arrangement in lieu of through the
digester access hatches.
Future options for the use of the gas storage facilities at the secondary digesters are addressed in
Section 8.
5.5.9 Solids Dewatering
Centrifuges
Digested solids are dewatered through the use of one 270 gpm (Sharples) centrifuge and one 80
gpm (Byrd) centrifuge. Both centrifuges are located in the solids building. Solids are fed to the
centrifuges with two variable speed progressive cavity pumps, each rated at 300 gpm. Dewatered
solids can be loaded directly to land disposal trucks through a conveyor system including small
cake hopper and loadout conveyor, or through a conveyor, cake hopper, and progressive cavity
pump. The normal mode of operation is to utilize the 270 gpm (Sharples) centrifuge, the
conveyor, cake hopper, and truck loadout conveyor system.
Solids Handling Building
The Solids Handling Building is located west of the DAFT and houses the centrifuges. The
building also contains a polymer system with one mix tank, one feed tank, polymer transfer
pump, and polymer feed pumps.
Solids Drying Beds
Twenty-four solids drying beds are situated at the southwest corner of the plant. Each bed is
30 -feet X 69 -feet. Bed numbers 1 through 23 are asphalt lined and bed number 24 is lined with
concrete.
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Supernatant Lagoons
Two supernatant lagoons exist along the south penmeter of the treatment plant. The ponds have
bottom dimensions of 157 -feet X 407 -feet with a 3:1 side slope and 15 -foot sidewater depth.
Total capacity of the lagoons is 20,643,000 gallons. Currently, centrifuge centrate is pumped to
the south supernatant pond for storage, and the north pond is currently not in use. Only centrate
is being directed to the lagoon system at the present time.
Future options for solids dewatering and the Solids Building are addressed in Section 9.
5.5.10 Miscellaneous Systems/Facilities
Air Emissions Control System
The Yakima Regional WWTP currently controls air emissions from the Headworks Building,
Influent Building, Trickling Filters, Trickling Filter Pumping Station, 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, and 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 15 per cent solution and the caustic soda is either a 30 percent or 50 percent
solution. Both solutions are available from chemical suppliers. The chemistry involved with the
packed tower control 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.
Safety, Reliability and Staff Issues
➢ The pH and ORP meters are calibrated every two weeks and show very little drift
between calibrations. The hypochlorite tank is in excellent condition and the level
monitoring system works well. The hypochlorite feed pumps are the constant speed
diaphragm type with a manually adjustable stroke length typically set at 25 percent.
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> There are no major maintenance problems. Lighting, HVAC, and safety provisions in the
chemical room are adequate. Hypochlonte consumption is approximately two deliveries
per year or 9,600 gallons.
> The system is functioning adequately and is effectively removing air emissions.
Electrical System
The existing plant electncal power distribution system consists of medium voltage distribution at
12.47 kV, three-phase, with on-site transformation to 480 volts, three-phase. Pacific Power &
Light provides power service to the plant via an overhead utility line protected by a pole mounted
utility fuse rated for 100 amps.
At the on-site point of service, the single utility three-phase line is divided into two sources that
supply the plant 15 kV switchgear. From the utility connect point through the remainder of the
plant there are dual sources of normal power supply for most plant process areas. The process
areas where a second normal power supply is not present are as follows: Food Process Water
Pumping Station, Chlorination Building, Dechlorination Building, and the Intermediate Degntter
Pump Station.
In the above process areas, the engine generator, located in the influent building, provides a
second source of power to assure that the minimum treatment is provided even under utility
power failure conditions. The existing engine generator is rated at 400 kW. Typical loading on
the unit during power failure events shows that an additional 100 kW of 20 horsepower and less
loads could be added to the essential electrical power bus without overloading the generator. The
engine generator supplies the power to the essential electrical power bus during utility power
failure events. The existing engine generator set was installed in 1972. The unit likely requires a
complete overhaul/inspection. Operations staff would prefer to install a natural gas fired unit.
Problems associated with replacement of the existing unit are that the natural gas fired unit
would require additional space since this type of unit is larger, and natural gas service is not
readily available on-site. Sufficient space within the existing generator room is not likely
available.
In general, the electncal power distribution system has adequate capacity for load growth in most
all process areas. A three-year electrical maintenance program was completed recently. The
electrical equipment maintenance program has minimized nuisance electrical problems and
unscheduled outages.
Power feeders, transformers, switchgear, and motor control centers appear to have a minimum of
twenty years of useful life if consistent maintenance is performed over that period.
The VFDs that operate the four 400 horsepower blowers are far less efficient and generate
significantly more harmonic distortion on the electrical power system than newer technology
units. As discussed in previous paragraphs under the aeration basin systems, the VFDs are near
the end of their useful life, are old technology, and it is difficult to find spare parts for them.
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Safety, Reliability and Staff Issues
> The electrical system recently completed an annual maintenance plan with ETI. The City
plans to go to a 5 -year maintenance program.
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.
Safety, Reliability and Staff 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.
➢ Additional circuit breaker capacity is needed in the Administration Building.
➢ 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.
> Alternative to expansion of the Administration Building is to build a new administration
building and/or expand the lab in the current solids handling building.
> Expansion of the Administration Building should be considered to the west or north.
➢ It may be possible to move the process lab somewhere else (i.e. it may be combined with
solids lab or, if the Chlorine/S02 systems are removed, may convert this space for the
process lab).
> A backflow preventer is needed for the lab water supply in the Administration Building.
> If the Administration Building is expanded, additional storage area should also be
considered.
Accessory Buildings
Accessory buildings include two garages and one workshop located west of the primary and
secondary digesters.
Safety, Reliability and Staff 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.
5.6 Summary
Table 5-6 summarizes the capacity rating evaluation of each unit process at the Yakima WWTP,
IIIsetting capacity at the most restrictive design critena. The table identifies capacity of current
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facilities and required capacity at year 2020 projected loading conditions. The following
highlights the capacity rating summary, and details general findings and recommendations
regarding the existing wastewater treatment facilities.
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Table 5-6 - Summary of Unit Process Capacity
Unit Process
Units
Average2
Firm Capacity
Maximum3
Month
Peak°
Hour
% Util
Vs. Year 2020 Flow/Load
Average Maximum Peak Hour
Month
Comment
Bar Screens & Screenings
Compactor
mgd-
-
40
60%
17 94
-
38.01
Sufficient capacity
Grit Removal
mgd-
-
40
60%
17 94
-
38 01
Sufficient capacity
Flow Measurement
mgd-
-
40
60%
17 94
-
38.01
Sufficient capacity
Primary Clarifiers
mgd
30 1
63 4
48%
17 94
22.78
38.01
Sufficient capacity
Trickling Filters Pumping
Station
mgd-
-
36
67%
-
-
38.01
Sufficient capacity at future flows.
Not all peak flow directed to units.
Trickling Filters
mgd-
13 75
-
100%5
-
22.78
-
Sufficient capacity at current flows.
Limited reserve capacity
Aeration Basins
mgd
-
12.15
-
100%5
-
22.78
-
Sufficient capacity at current flows.
Insufficient reserve capacity for
future conditions.
Secondary Clarifiers6
mgd
18.5
-
31 4
78%
17 94
-
38.01
Insufficient capacity at future peak
hour flows. Insufficient
redundancy per WDOE
requirements.
RAS Pumping
mgd
-
-
32.4
74%
-
-
38.01
Sufficient capacity for current
peak -hour flows. Insufficient
capacity for future flow conditions.
WAS Pumping
gpm
-
-
800
14%
-
-
186
Sufficient capacity Pumps too
large for WAS flows.
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Table 5-6 - Summary of Unit Process Capacity, cont.
Unit Process
Units
Average2
Firm Capacity
Maximum'
Month
Peak4
Hour
% Util
Vs. Year 2020 Flow/Load
Average Maximum Peak Hour
Month
Comment
Chlorine Contact Chamber
mgd
18.9
-
57 4
60%
17 94
-
38.01
Sufficient capacity for current flow
conditions. Insufficient capacity to
meet year 2020 maximum month
conditions.
Chlorination Facilities
lb CL2/d
1,000
40%
-
1,552
Sufficient capacity for current tlow
conditions. Capacity could be
added to serve beyond year 2020
conditions.
Outfall
mgd
45 0
53%
38.01
Sufficient capacity for current and
year 2020 peak flow
DAF Thickener
Ib TSS/d/sf
-
20 0
-
44%
13 8
-
Sufficient capacity to serve to year
2020 conditions. No system
redundancy provided.
Primary Digesters
HRT (d)
21 1
37 7
-
70%
(1)
(1)
(1)
Sufficient capacity with all in
service.
Secondary Digesters
HRT (d)
14 7
9.0
-
50%
(1)
(1)
Sufficient capacity
Centrifuges
gpm
-
270
-
36%
-
152
-
270 gpm unit operating.
Insufficient redundancy
'Refer to Section 9 for discussion on digester capacity expansion options.
2Current Average, 11.28
'Current Maximum Month, 14.38 mgd.
4Current Peak Hour, 24 mgd.
5Combined organic capacity of Trickling Filter/Activated Sludge process is approximately 16 mgd. Plant currently at 75% utilization for combined organic capacity
6Reliability standards limit secondary clarifier capacity to 12.3 mgd average and 24 6 peak hour with one clarifier out of service.
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City of Yakima
Mandatory Wastewater Facilities Plan
SECTION 6
Identification of Selected
Wastewater Treatment Strategies
October 2000
prepared by:
Dan Harmon
J.B. Neethling
HDR Engineering, Inc.
reviewed by:
Tony Krutsch
John Koch
City of Yakima
DRAFT
City of Yakima
SECTION 6
Identification of Selected Wastewater
Treatment Strategies
6.1 Introduction
A wide range of alternatives were considered for expanding the Yakima Regional WWTP to
meet future capacity and regulatory effluent quality requirements. This Section describes the
evaluation process used, identifies alternatives considered, summarizes evaluation results, and
provides recommendations for future wastewater treatment modifications.
6.2 Evaluation Process
Alternatives were identified and evaluated through an interactive process involving City and
consultant staff. A flow chart of the evaluation process is presented in Figure 6-1. Major
elements of the process are described below.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 1
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Figure 6-1. Yakima Facilities Evaluation Flow Chart
Meet with
Yakima to Review
WWTP Staff
Define Process
Methodology and
Evaluation Criteria
/ \
Brainstorm and
Screen Ideas
\ /
Coordinate Design
Development
Respond to
City Review
Comments
Modify
Recommended
Facilities/
Phasing
Detailed
Development
and Evaluation
Planning Goals
Planning Projections
Regulatory Issues
Existing Conditions
Internal HDR
Review
City Review
Workshop
Fina Plan
Recommendations
Design Flows/Loadings
Preliminary Process Sizing
Comparison of Altematives
Planning -Level Costs
Phasing of Attematives
Recommendations
HDR ENGINEERING, INC
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Preliminary Findings
Facility Requirements
Site Constraints
Phasing
Cost Estimates
Page 2
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6.2.1 Define Process Methodology and Evaluation Criteria
To provide a consistent planning basis, HDR developed an evaluation methodology for the
wastewater facilities. This process defined evaluation criteria, outlined the decision-making
process, and prescribed opinion of probable cost estimating procedures. The evaluation criteria
are listed in Table 6-1. Except for the opinion of probable cost, these criteria were applied on a
non -weighted qualitative basis when evaluation of alternatives was performed.
Table 6-1. Evaluation Criteria
Technical Criteria
Community/Environmental Criteria
• Proven performance — proven treatment
process(es)
• Reliability — ability to consistently meet
permit
• Complexity
• Flexibility — to accommodate changes in
treatment requirements/growth/load
Operations & Maintenance Criteria
• Noise potential
• Aesthetic impact
• Air quality impacts
• Truck traffic
• Operator intensive — sensitive to operator
attention
• Maintenance intensive — major
new/additional equipment
• Energy/chemical intensive — sensitivity to
increased costs
Implementation Criteria
Cost Criteria
• Capital
• Operating
• Phasing — ability to match units with growth/need
• Ability to maintain operation during construction
• Ease of construction
6.2.2 Identify and Screen Ideas
Potential alternatives for expanding or improving the Yakima Regional WWTP were identified
by City/HDR and reviewed by City staff. A full list of the alternatives identified is provided in
Table 6-2. Following the initial alternative development, an initial screening step was conducted
to eliminate ideas that were fatally flawed, technically unproven, excessively expensive, or
otherwise unworthy of detailed evaluation.
The initial screening labeled each idea as "retain," "fail," or "feature." These labels are defined
as:
➢ Retain, In -Scope: Carry idea forward to detailed alternative analysis as part of this
facilities plan.
➢ Retain, Not -in -Scope: Valid idea, but outside the scope of this study. Address in
concurrent or future studies.
➢ Fail: Idea is fatally flawed. Do not carry forward to detailed alternative analysis.
➢ Feature: Idea should be considered as a component of other ideas generated, or as a
component of the predesign.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 3
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Table 6-2. Alternative Development Ideas and Initial Screening Results
Idea Initial Screening Result
Programmatic Measures:
PM 1
PM2
Septage:
SEPI
SEP2
SEP3
SEP4
Identify/reduce potential point sources of ammonia
Implement demand management
New septage dumping station with use of existing
septage receiving facility
New on-site septage receiving station
Accept discharge at WWTP at current location with
revised receiving facilities
End accepting discharge at WWTP and direct all to
Cheyne Landfill site
SEP5 Land application of domestic septage with seasonal
storage
Headworks/Preliminary Treatment:
IPI Upgrade existing headworks to address insect problems
IP2 Repair and rehabilitate grit hopper
IP3 Replace existing grit storage hopper
IP4 Upgrade existing flow measurement
IP5 Install access covers on grit classifiers
IP6 Install covers at influent channels and influent flow split
box
Primary Treatment:
P1 Retain exist influent flow split box. automatic scum
removal
P2 New influent flow split structure with flow split weirs,
and scum removal equipment
P3 Replace clarifier sludge collection mechanisms
P4 Repair settlement and concrete walls at clarifier and
influent channels
P5 Install new technology density meters and flow meters
for primary sludge
P6 Replace scum piping at primary treatment facilities
P7 Install new access doors and windows for sludge
transfer building
P8 Relocate sump discharge from sludge transfer building
Trickling Filter System:
TFI Install chlorination at trickling filters
TF2 Install new plastic media in trickling filters
TF3 Install enhanced forced ventilation on trickling filters
TF4 Install covers over walkways at trickling filters
TF5 Install basin isolation at intermediate degritters
TF6 Repair/replace trickling filter isolation gate at secondary
diversion manhole
TF7 Install covers at primary effluent flow split and
intermediate degritter locations
TF8 Split Box Level controller
Activated Sludge System:
AS 1 Repair primary effluent flow split system to eliminate
excessive control gate modulation
Build new activated influent flow split box
AS2
AS3
AS4
AS5
Replace existing RAS/WAS Pumping Station
Retain existing RAS/WAS Pumping facilities. Install
separate pumping station for new facilities.
Build new aeration basin effluent split box
Feature. Consider during pre -design
Retain. Include in summary memorandum
Retain for evaluation
Retain for evaluation
Fail. Site facility access and building layout
constraints limits control of facility use and
compromises WWTP•site safety and security
Retain. But not in current scope of this study
Fail. Not in current scope of this study
Feature. Consider as regular maintenance item
Retain for evaluation
Retain for evaluation
Feature. Consider as regular maintenance item
Feature. Consider as regular maintenance item
Feature. Consider during pre -design
Retain for evaluation
Retain for evaluation
Feature. Consider during pre -design
Feature. Consider during pre -design
Feature. Consider during pre -design
Feature. Consider during pre -design
Feature. Consider during pre -design
Feature. Evaluate alternatives
Feature. Consider during pre -design
Retain for evaluation. Evaluate as part of AS9
Retain for evaluation. Evaluate as part of AS9
Feature. Consider during pre -design
Feature. Consider during pre -design
Feature. Consider during pre -design
Feature. Consider as option during pre -design
Feature. Consider as option during pre -design
Feature. Consider during preliminary design
Feature. Consider during predesign
Retain for evaluation
Retain for evaluation. In conjunction with AS8
& AS9
Feature. Consider during related altematives
evaluation
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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Table 6-2. Alternative Development Ideas and Initial Screening Results
Idea
Initial Screening Result
AS6
AS7
AS8
AS9
AS10
ASI 1
AS 12
AS13
AS 14
AS15
AS 16
AS 17
AS18 Use BAF
AS 19
41) AS20
AS21
Install new circular secondary clarifier
Retrofit existing Trickling filter clarifier
Retrofit existing clarifier mechanisms.
Upgrade existing aeration basins, build equivalent third
aeration basin train, and upgrade trickling filters for
higher organic loading
Upgrade existing aeration basin, build equivalent third
aeration basin train, and increase process MLSS to meet
design loadings
Upgrade existing aeration basins, build additional
aeration basin capacity without increase in MLSS
concentration
Upgrade existing aeration basins and upgrade trickling
filters to handle loads to filter limit
Equalize centrate recycle and treat with activated sludge
system
Pre -treat centrate recycle and discharge to secondary
process
Enhance struvite formation
Use higher rate activated sludge reactor (MLSS above
2200 mg/L)
Provide step feed
•
Provide contact stabilization
Provide enhanced aeration control
Provide cyclical aeration for nitrification/denitrification
in same basin
Disinfection:
DI Continue current chlorination/dechlorination system.
D2 Convert to hypochlorite
D3 Convert to bisulfite
D4 Microfilter
D5 Breakpoint chlorination
D6 Irradiation
D7 On-site hypochlorite generation
D8 Ultraviolet Light — Open channel low pressure
D9 Ultraviolet Light — Open channel medium pressure
D10 Ultraviolet Light — Enclosed channel medium pressure
Primary Sludge Thickening:
PTI Continue thickening in primary clarifiers, install new
density meters and flow meters
PT2 Gravity thickener
PT3 Gravity belt thickener
WAS Thickening:
WTI Install second DAFT unit for system redundancy
WT2 Install gravity belt system for thickening redundancy
WT3 Install press -type thickening units (SOMATS) for
system redundancy
WT4 Install rotary drum system for thickening redundancy
WT5 Install gravity thickener for system redundancy
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Retain for evaluation. Study site location
alternatives
Retain for evaluation
Feature. Consider during predesign.
Retain for evaluation
Retain for evaluation
Retain for evaluation
Retain for evaluation. Evaluate as part of
aeration basin expansion alternatives and TF -3
Retain for evaluation. Part of Section 9
Retain for evaluation. Part of Section 9
Fail. Not needed
Retain for evaluation
Feature. Consider during predesign. Already
part of current design
Fail. Not cost effective. Not effective for
lower ammonia limits
Feature. Consider during predesign for new
basins. Already part of current operation
Feature. Consider during predesign
Fail. Not needed in near-term and not
compatible with existing process. Plan for
separate anoxic zone during site planning
Retain for evaluation. Expand contact basin
capacity after 2020.
Retain for evaluation.
Retain for evaluation.
Fail. Too expensive. Water reuse not
anticipated
Fail. Chemical costs too high
Fail. Not proven technology
Fail. No driving force to change
Retain for evaluation
Retain for evaluation
Retain for evaluation
Feature. Evaluate with alternative P5
Fail. No driving force to change
Fail. No driving force to change
Retain for evaluation
Retain for evaluation
Fail. Not proven technology for WAS
Retain for evaluation
Fail SC provide gravity thickening
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Table 6-2. Alternative Development Ideas and Initial Screening Results
Idea
Initial Screening Result
WT6 Use Bird Centrifuge or redundant centrifuge unit for
thickening redundancy
Gas Management:
GM1 Cogeneration
GM2 Fuel cells
GM3 Direct generation of heat
GM4 Waste gas incinerators
GM5 Gas -driven prime mover (aeration)
GM6 Gas storage — medium pressure
GM7 Gas storage — low pressure. Correct current deficiencies
GM8 New boiler — dedicated to fuel oil
GM9 Convert boiler to natural gas/digester gas operation
GM I O Piping modifications
Fail. Insufficient capacity for projected loads
Retain for evaluation
Fail. Very expensive technology
Potential feature. Explore possibilities
Fail. Currently not required.
Fail. Not cost effective, specialized maintenance
Fail. No driving force to change
Feature. Consider as regular maintenance item
Retain for evaluation. Included in Section 8
Retain for evaluation. Included in Section 8
Feature. Consider as regular maintenance item
6.2.3 Detailed Development and Evaluation
Alternatives surviving the initial screening step were developed in detail. Facility sizing and cost
estimating were conducted for year 2020 and ultimate build -out design conditions. Alternatives
were compared based on cost and non -economic criteria. Based on this analysis, preliminary
recommendations for facility improvements were developed and are presented in each unit
process alternative evaluation section.
6.3 Existing Facilities Needs
During the treatment plant review session with operations personnel and wastewater division
staff, facility improvements were identified that should be included as key features in future plant
upgrade projects. These improvements include:
6.3.1 Headworks/Preliminary Treatment
➢ Add screening to all building penetrations for insect control in screenings room.
➢ Upgrade/improve the grit storage hopper including correction of the vibratory unit
operation.
6.3.2 Primary Treatment
➢ Provide for automated scum removal at the influent flow split box if retained in the
future.
➢ Rehabilitate or replace the sludge collection mechanisms.
➢ Repair settlement areas and concrete walks around the pnmary clarifiers and influent
channels.
➢ Install new technology density meters (Toshiba) for clarifier sludge.
➢ Replace scum piping at primary treatment facilities to eliminate fouled pipelines, pipeline
bends, etc.
➢ Install new access doors and windows for the Sludge Transfer Building.
➢ Re -locate sump discharge from the Sludge Transfer Building. Consider extension of the
sump discharge to the primary influent flow split structure.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 6
• ➢ Provide for repairs to the secondaryeffluent flow split system (while existing unit is in
DRAFT
6.3.3 Secondary Treatment
service) to eliminate excessive modulation of control gates at the split structure. Provide
for better flow control at lower bypass rates.
➢ Install chlorination facilities at the trickling filters or trickling filter influent to provide for
control of snails.
➢ Address problems with water accumulation in the trickling filter distributor gear boxes.
➢ Install covers over walkways at the trickling filters and intermediate degritter area.
➢ Install basin isolation facilities at the degritter area to enable removal of either basin from
service without impacting the operation of the other basin.
➢ Repair/replace or block off the trickling filter clarifier isolation gate at the secondary
effluent diversion manhole.
➢ Repair or replace the disinfection bypass gate in the secondary effluent diversion
manhole.
➢ Install a new sludge pumping system for the Trickling Filter Clarifier. Eliminate the need
for manual pumping of the underflow from the clarifier.
➢ Install new dewatering facilities for the Trickling Filter Clarifier. Alternatively, install a
connection to the influent well to enable pumping from a portable diesel pump.
➢ Complete recommended repairs to Aeration Basin No. 4 floor slab and evaluate the other
basins for the need for similar repairs.
➢ Improve support of aeration basin low pressure air grids.
• ➢ Install repair coating on aeration basin interior walls where concrete corrosion and wear
are occurring.
➢ Improve cleaning of the existing secondary clarifier launders by replacing the inboard
launders with peripheral units and installing launder brushes/wipers.
➢ Replace or rehabilitate the existing secondary clarifier sludge collection mechanism
drives, scum boxes, and surface skimmer mechanisms is recommended.
➢ Install dedicated valves for piping for WAS and secondary scum facilities.
6.3.4 Disinfection
•
➢ Install chlorine scales with better scale resolution to improve chlorine consumption
monitoring.
➢ Relocate priority pollutant sampling closer to the outfall structure.
➢ Install a partial structure for protection of the sampler from the weather.
6.3.5 Non -Potable Water System
➢ Relocate the chlorine contact chamber baffle walls near the C2 pumping units (installed
above the basins) to eliminate short circuiting.
➢ Replace older hose hydrants that are undersized to improve low delivery pressures.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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6.3.6 Miscellaneous Systems/Facilities
➢ Replace fluorescent lighting in basement areas where lighting intensity is poor.
➢ Replace light fixtures at clarifiers to resolve issues involved with lamp replacement.
➢ Improve electrical systems in the Administration Building.
➢ Install a backflow preventer in the Administration Building for lab water supply.
➢ Add additional truck storage for the solids handling vehicles.
➢ Add additional storage shed for miscellaneous vehicles.
➢ Add partial enclosures for all composite samplers for protection from hot and cold
weather conditions.
6.4 Alternatives Development and Screening
A full listing of the ideas for improving and expanding the Yakima Regional WWTP are
presented in Table 6-2. Table 6-3 summarizes the number of ideas generated, and the results of
the initial screening step.
Table 6-3. Summary of Initial Alternative Development and Screening
Treatment Process Area
Number of Ideas by Screening Designation
Retain
Fail
Feature
Total
Programmatic Measures
1
0
1
2
Septage Handling
2
3
0
5
Headworks/Preliminary Treatment
2
0
4
6
Primary Treatment
2
0
6
8
Trickling Filter System
2
0
7
9
Activated Sludge System
10
3
7
20
Disinfection
5
4
0
10
Primary Sludge Thickening
0
3
1
4
WAS Thickening
5
1
0
6
Gas Management
3
4
3
10
Total
33
18
29
80
6.5 Detailed Evaluation of Alternatives
Following the initial development and screening steps, the remaining alternatives were developed
in detail and compared against evaluation criteria. This section identifies the alternatives
evaluated, presents major design criteria used in development of the alternatives, and describes
the opinion of probable cost estimating methodology.
6.5.1 Summary of Alternatives Developed
Table 6-4 lists the alternatives considered for each process area. In a few instances, ideas
rejected during the initial screening step were revisited to maintain consistency with the facility
planning process and to address specific issues raised by the planning team. No new ideas were
introduced during this phase of the study.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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Table 6-4. Alternatives Subjected to Detailed Analysis
6.5.2 Design Criteria
An array of design criteria was established to guide development of the treatment alternatives
considered for the Yakima facility.
6.5.2.1 Planning Horizon
In most cases, alternatives were developed for two projected flow and loading conditions: year
2020, and ultimate build -out. The ultimate build -out condition provided a long-term economic
and non -economic comparison of the alternatives, and identified ultimate facility requirements
and space needs. The 2020 scenario provided a near-term comparison of economic, operational,
and implementation factors.
6.5.2.2 Flows and Loadings
Initial development of alternatives was based on the maximum flow and loading condition
presented in Section 4. This condition was selected because it represents the worst-case planning
scenario for site space requirements. In most cases, the impact of using the most -likely or
minimum flow conditions was considered, at least qualitatively. Selection of the maximum flow
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 9
Septage Handling
Headworks/Preliminary Treatment
•
•
New dumping station with use of existing septage
receiving facilities.
Replace existing septage receiving facility with new
station.
•
•
Repair and rehabilitate existing grit hopper
Replace existing grit hopper
Primary Treatment
Trickling Filter System
•
Retain existing influent flow split box and automate
scum removal.
•
Install new plastic media in trickling filters.
•
Install new influent flow split box and eliminate
scum removal requirements at this location.
•
Install enhanced forced ventilation on trickling
filters.
Activated Sludge System
Disinfection
•
Replace existing RAS/WAS Pumping Station.
•
Maintain existing chlorination/dechlorination system
•
Retain existing RAS/WAS Pumping facilities and
and expand contact basin capacity.
construct separate pumping facility for new process
units.
•
Replace chlorination system with
hypochlorite/bisulfite system.
•
New secondary clarifier
•
Retrofit existing Trickling Filter Clarifier
•
Replace chlorination system with open channel low
•
Install new media in trickling filters to reduce
pressure ultraviolet light.
aeration basin expansion requirements.
•
Replace chlorination system with open channel
•
New aeration basin capacity with trickling filter
medium pressure ultraviolet light.
improvements.
•
Replace existing chlorination system with closed
•
New aeration basin capacity to handle all future
loads.
channel medium pressure ultraviolet light.
•
Equalize centrate recycle and treat with activated
WAS Thickening
sludge system. (Section 9).
•
Install redundant DAFT unit.
•
Pre -treat centrate recycle and discharge to secondary
•
Gravity belt thickening system for redundancy
process. (Section 9).
•
Rotary drum system for system redundancy.
•
Install new aeration basin capacity and operate high
rate activated sludge reactors (MLSS >2200 mg/L).
6.5.2 Design Criteria
An array of design criteria was established to guide development of the treatment alternatives
considered for the Yakima facility.
6.5.2.1 Planning Horizon
In most cases, alternatives were developed for two projected flow and loading conditions: year
2020, and ultimate build -out. The ultimate build -out condition provided a long-term economic
and non -economic comparison of the alternatives, and identified ultimate facility requirements
and space needs. The 2020 scenario provided a near-term comparison of economic, operational,
and implementation factors.
6.5.2.2 Flows and Loadings
Initial development of alternatives was based on the maximum flow and loading condition
presented in Section 4. This condition was selected because it represents the worst-case planning
scenario for site space requirements. In most cases, the impact of using the most -likely or
minimum flow conditions was considered, at least qualitatively. Selection of the maximum flow
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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condition primarily affects the sizing of liquid stream processes and pipelines, but it has minimal
impact on solids stream facilities.
6.5.2.3 Effluent Quality Requirements
Development of all unit processes was based on meeting the effluent quality requirements
presented in Section 2. For the purposes of future facility evaluation, nominal effluent quality
requirements are anticipated to be consistent with values currently permitted for the Yakima
Regional WWTP discharges.
6.5.2.4 Biosolids
Section 9 provides a detailed evaluation of biosolids processing alternatives for production of a
Class A biosolids product in lieu of the Class B product currently produced by the existing
digestion facilities. Alternatives for enhancement of the biosolids are also addressed in Section
9.
6.5.2.5 Treatment of Excess Peak Flows
Based on an initial assessment of the treatment facilities to meet effluent quality requirements,
the following baseline conditions were established regarding flow routing to various treatment
processes:
D All flow receives preliminary treatment and primary treatment.
D Capacity of the existing trickling filters will be used to the maximum extent possible.
> All flow receives secondary treatment, disinfection, and dechlorination (if needed).
6.5.2.6 Design Development Criteria
Design development criteria were established to facilitate a more uniform approach to process
selection and facility layout. The criteria are briefly described below.
Process Sizing Criteria
The process sizing criteria were presented in Section 5. These criteria specify design loading
rates and operating parameters for critical unit treatment processes. Examples include clarifier
overflow rates, aeration basin mixed liquor concentrations, filter loading rates, and chlorine
contact basin detention times, etc.
Site Development Criteria
Site development cnteria address such issues as access to buildings, equipment and piping; space
requirements for employee facilities; air quality and noise control; landscaping; and setbacks and
height limitations. An essential criterion was that there would be minimal increase in operations
or maintenance staff during any near-term expansions.
HDR ENGINEERING, INC
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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Reliability/Redundancy Criteria
These critena define reliability and redundancy requirements for unit processes, critical
equipment, electrical supply facilities, and instrumentation and control systems.
6.5.3 Development of Opinion of Probable Costs
The opinion of probable cost is the estimated cost of 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 opinion of probable 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 data are:
➢ Cost data for recent HDR designed WWTP expansion projects, adjusted to 2000 dollars.
➢ Recent costs for other, similar facilities, adjusted to regional market conditions.
➢ Equipment pricing from manufacturers, with installation, structure, and housing costs
based on unit prices from recent HDR project designs.
All opinion of probable costs include allowances for site work, yard piping, electrical and
controls. Factors for other allied costs were developed from recent construction projects. These
factors are presented in Table 6-5.
Table 6-5. 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%
For most treatment processes, the economic comparison of alternatives is strongly driven by the
opinion of probable costs. Consequently, O&M costs were considered only where there was a
substantial difference in O&M requirements between the alternatives.
Individual O&M costs are based on comparable costs presently incurred by the Yakima Regional
WWTP. The labor rate for collection and treatment staff is estimated at $75,000 per year. Plant
employees are union members, and the plant is operated 7 days per week, 24 hours per day. Two
thousand and eighty hours per year for each full time employee, less ten and a half weeks of
benefit and training time, the total working hours per year for each full time employee 1,660.
• The current rate for power at the treatment plant (including demand charge impacts) is $0.053 per
kilowatt-hour, and the rate for diesel fuel is approximately $1.09 per gallon.
HDR ENGINEERING, INC
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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6.6 Septage Handling Alternatives
The existing septage receiving facility located inside the Influent Building is not typically used.
The City does not encourage septage dumping at the Yakima Regional WWTP due to the risk of
toxic chemical introduction from industrial septage, the difficulty in controlling site access, and
site safety due to the location of the existing receiving facility in the interior of the WWTP site.
The existing receiving facility is also difficult to access with commercial septage hauling
vehicles, is not designed for vehicle washdown, and does not have provisions for measurement of
the septage volume received. When the Yakima Regional WWTP was constructed in 1983, the
intent was to eliminate the existing septic tank disposal systems in the Yakima Urban Area, and
to provide sewer service to developing areas in lieu of septic tank disposal systems in the future.
If septage were to be received, the rate at which septage can be added to the influent stream of
the wastewater treatment plants is determined by the types of processes used and the available
capacity of the treatment facility. A detailed analysis of the impact of septage addition on the
process performance would be necessary for final design of a septage receiving facility. For a
less detailed analysis where septage receiving is not considered a cntical element for the plant
treatment process design, standard EPA guidelines can be used to estimate the treatment plant
capacity for septage addition based on hydraulic capacity. Capacity for septage addition at the
Yakima Regional WWTP was developed based on the following:
➢ Design flow, mgd (Year 2020) = 17.94
➢ Current average flow, mgd = 11.28
• ➢ Q present/Q design = 0.65
➢ Septage added = 0.60 to 0.75%
•
If the treatment process were sized to accommodate the additional organic loading added by the
septage, in accordance with EPA guidelines (EPA/625/R-24/002), the expanded wastewater
treatment plant could accommodate between 104,000 to 130,000 gallons of septage per day.
Estimates indicate that the Yakima Region currently generates approximately 100,000
gallons/day of industrial septage. Estimates of domestic septage generated within the study area
are not known.
The City has indicated they are not promoting septage services at the WWTP; however, it is
recognized there may be a need for the City to provide limited service. Because it is difficult to
project the quantity of septage that would be received by a new facility, this study anticipates that
the receiving station and pumping facilities would be designed for peak 2020 conditions of
130,000 gallons per day. Typically, septage receiving facilities should be sized to hold septage
for up to one week (Total storage of approximately 750,000 gallons) in the event of a plant upset,
surge in septage pumping, or other conditions that prevent the discharge of septage into the
treatment stream. The City of Yakima has required that the septage facilities be designed to
deliver septage directly to their digester facilities. This would enable reduction of the storage
capacity to more typical receiving station levels. The existing septage collection sumps in the
Influent Building are sized for approximately 13,000 gallons each for a total storage capacity of
26,000 gallons. A standard septage holding facility design utilizes a minimum of two below
grade 14,000 gallon receiving/storage tanks with associated dumping/loadout facility and transfer
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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pumping station. For the purposes of this evaluation, it is anticipated that four 14,000 gallon
receiving/storage tanks (Total of 56,000 gallons) would be installed for the new storage option.
Should the septage receiving facilities be expanded at the WWTP, an additional full time
operator will be required to handle the laboratory testing and maintenance activities associated
with this expanded service.
6.6.1 Alternatives Considered
Section 5 identifies 14 minimum design criteria to be considered when constructing a new
septage facility at the Yakima Regional WWTP. Two alternatives were evaluated to meet the
minimum design requirements outlined:
➢ New receiving facility with pumping system that delivers to the existing septage storage
sumps in the Influent Building. Re -plumbing of the septage storage tank pumping to
enable direct delivery of septage to the digestion facilities.
➢ New Septage Receiving Building including new septage storage tankage and pumping
systems configured to deliver septage to the digesters.
6.6.1.1 New Septage Receiving Station Using Existing Septage Storage
Tanks
This approach would take advantage of existing septage storage and pumping facilities in the
Influent Building. A flow schematic is shown on Figure 6-2. Two new septage storage tanks of
14,000 gallons each would be constructed with this alternate. The storage tanks would be
positively ventilated and the existing dumping station would be maintained, primarily for WWTP
operational personnel access and equipment/machinery washdown. New discharge pumps and
piping would be added to enable pumping to the digester complex via existing primary sludge
piping systems. A new septage receiving station with the new septage storage tanks would be
installed at the northwest corner of the plant site, north of the Administration Building and
accessible from a turnout on East Viola Street. The station would be located in close proximity
to the Influent Building to minimize the transfer piping length. Portions of the new structure
would be located over the influent sewers in the area. The site penmeter fencing would be
modified to allow 24-hour access to the facility. The receiving station would also include an
enclosed building sized sufficiently for access by the City's sewer cleaning equipment.
The building would include a restroom, washdown systems, air removal system, truck stack
exhaust, package -type screening system to remove all larger trash items and other key amenities
identified in the minimum design criteria. Ventilated air collected from this area would be
directed to the existing trickling filter air ventilation system. A cardkey system would be
installed and the screening/acceptance equipment would be automated with pH and conductivity
monitoring to shut down the acceptance of toxic loads. A pumping sump with force mains
flowing to the Influent Building would be installed to deliver the septage to the existing or new
storage tanks for holding, testing, and metering to the digesters or the liquid treatment process.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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DRAFT
6.6.1.2 New Septage Receiving Station with Aerated Holding Tanks and
Pumping System
In this alternative, the existing septage receiving facilities and tankage would be abandoned for
septage use and a new, stand-alone, septage receiving station with 56,000 gallons of
receiving/storage capacity would be constructed. See Figure 6-3. To enable better delivery to
the digestion complex and easy access to the station, it would be located along the west frontage
road adjacent to the Garage Offices. A drive through would be installed east of the frontage road
and the site perimeter fencing would be changed to allow 24-hour access to the facility. The new
septage facility would be configured in a similar manner to the above alternative. In addition,
four aerated holding tanks would be installed to allow storage of received loads until toxicity
testing is completed and the load(s) can be pumped to the digesters or liquid process.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 14
DRAFT
• Figure 6-2. New Septage Receiving Station using Existing Septage Storage
•
SEPTAGE UNLOADING SCREENING
STATION SYSTEM
FLOW TRANSFER
SUMP
NEW
SEPTAGE SUMP
EXISTING
SEPTAGE SUMP
TO INFLUENT DIVERSION
OR PRIMARY DIGESTION
Figur
e 6-3. New Septage Receiving Station with Aerated Holding Tanks and Pumping
Station
SEPTAGE UNLOADING
STATION
SCREENING
SYSTEM
AERATED SEPTAGE
STORAGE TANK
TRANSFER
PUMPING
TO INFLUENT DIVERSION
OR PRIMARY DIGESTION
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 15
•
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6.6.2 Alternatives Evaluation
➢ Both alternatives evaluated would address all design cntena presented in Section 5,
would be technically equivalent, and have similar maintenance requirements.
➢ The location of the new septage receiving station at the northwest corner of the site is less
desirable since a portion of the receiving facility may need to be installed over influent
sewers and the facility is in greater view to the public.
➢ The location of the septage receiving station for access along the north site boundary will
require a turnout be installed on Viola to the east creating additional traffic congestion in
the area.
➢ Installation of a new septage receiving station with integral holding tanks enables the
station to be located along the west frontage road, away from public view of the plant
entrance, and in closer proximity to the digester complex. The frontage road is better
suited for handling the truck traffic generated by this type of facility.
➢ Significant yard piping would be required between the Influent Building and the Digester
Complex, reducing the cost benefit of utilizing existing tankage for the new receiving
system.
➢ Implementation of the new septage facility along the Frontage road will be easier due to
less site utilities congestion and more room for construction activities.
The opinion of probable costs of the septage receiving alternatives are presented in Table 6-6.
Provisions for delivery of septage to the digesters and delivery of collected ventilation air to the
existing trickling filter system are included in the estimates. Because both systems have similar
operation and maintenance requirements, only facility opinion of probable costs are presented.
Expansion of septage receiving facilities will require the addition of another full-time operator
for laboratory monitonng and facility maintenance.
Table 6-6. Opinion of Probable Cost for Septage Receiving Alternatives
Unit
Opinion of Probabl
Receiving Station Using
Existing Holding Tanks
e Cost (to Build -out)
New Receiving Station With New
Holding Tanks
Facility Construction and Retrofits
Electrical (15%)
vC (7 %)
Site Work and Yard Piping
(25% Exist; 20% New)
Subtotal Costs
Contractor Overhead and Profit (15%)
Subtotal
Contingency (20%)
Subtotal
Sales Tax (8%)
Subtotal
Engineering, legal and fiscal (25%)
Total Opinion of Probable Cost
$675,000
$101,300
$47,300
$168,800
$992,400
$148,900
$1,141,300
$228,300
$1,369,600
$109,600
$1,479,200
$369,800
$1,849,000
$786.000
$117,900
$55,000
$157,200
$1,116,100
$167,400
$1,283,500
$256,700
$1,540,200
$123,200
$1,663,400
$415,900
$2,079,300
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 16
•
•
•
DRAFT
6.6.3 Preliminary Recommendations
If the City is mandated to construct a septage receiving facility for Yakima County by WDOE, a
new facility located along the west frontage road is recommended since it has better site control
capability, facility access closer to the digester facilities, and will provide a long term solution to
septage handling.
6.7 Headworks/Pretreatment Alternatives
The gnt storage hopper in the influent building has been used to store grit that is discharged from
the grit removal process. The existing gnt storage hopper is deteriorating due to problems with
the vibratory process that is leading to cracks and seepage.
6.7.1 Alternatives Considered
Section 5 identified 3 minimum design cnteria to be considered when retrofitting the existing grit
removal facilities at the Yakima Regional WWTP. Two alternatives have been evaluated to meet
the minimum requirements:
➢ Repair and rehabilitate the existing gnt storage hopper.
➢ Replace the existing gnt storage hopper with a new unit.
6.7.1.1 Repair and Rehabilitate Existing Grit Storage Hopper
Upgrades/improvements are needed on the existing grit storage hopper to extend the functional
life of the equipment to beyond the planning penod. Needed improvements include correction of
the vibratory unit operation, enhancement of air quality collection, and installation of controls for
seepage from the hopper to allow operations staff to maintain a truck under the hopper during
normal operation without accumulating unwanted seepage from the storage hopper above.
This alternate would remove the existing storage hopper from service including valves, gates and
vibratory equipment, for repair. 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. A new vibratory unit would be installed as a
replacement to the existing unit and a new gate valve with integral dnp rim that will be hard
piped to drain would be installed.
6.7.1.2 Replace Existing Grit Storage Hopper
Under this alternative, the problems associated with the existing storage hopper would be
eliminated. The new hopper would be designed to incorporate positive aspects of the previous
hopper, yet will be designed with steeper sidewalls and enhanced vibratory system to avoid the
problems associated with the existing hopper vibratory system. The new hopper would include
an HDPE liner to reduce surface fnction and provide added wear resistance.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 17
•
•
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6.7.2 Alternatives Evaluation
➢ Retrofits to the existing grit storage hopper will repair the deficiencies and lead to
smoother operation.
➢ Replacement with a new gnt storage hopper design to minimize vibratory action will
curtail the problems that the current unit has experienced.
➢ The new gnt storage hopper alternative will ensure better reliability is provided.
➢ Both alternatives offer similar operations benefits; however, a new hopper will likely be
less maintenance intensive than the existing unit.
➢ Both alternatives face similar construction/implementation issues including temporary
grit storage and existing equipment demolition activities.
The opinion of probable costs of the grit storage hopper alternatives is presented in Table 6-7.
Because both alternatives have similar operation and maintenance requirements, only facility
opinion of probable construction costs are presented.
Table 6-7. Opinion of Probable Cost for the Grit Storage Hopper Alternatives
6.7.3
Unit
Opinion of Probabl
e Cost (to Build -out)
Replace with New Hopper
$143,000
$21,500
$10,000
$28,600
Repair Existing Hopper
Facility Construction and Retrofits
Electrical (15%)
I/C (7 %)
Site Work and Yard Piping (20%)
Subtotal Costs
Contractor Overhead and Profit (15%)
Subtotal
Contingency (20%)
Subtotal
Sales Tax (8%)
Subtotal
Engineering, legal and fiscal (25%)
Total Opinion of Probable Cost
$118,000
$17,700
$8,300
$23,600
$167,600
$25,100
$192,700
$38,500
$231,200
$18,500
$249,700
$62,400
$312,100
$203,100
$30,500
$233,600
$46,700
$280,300
$22,400
$302,700
$75.700
$378,400
Recommendations
Since both the grit storage hopper options are similar in cost, the repair of the existing hopper is
recommended.
6.8 Primary Treatment Alternatives
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
Pnmary Clanfier 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 Primary Clarifiers Nos. 2 & 3. To alleviate these problems, a retrofit or
replacement of the split box structure has been proposed.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 18
•
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6.8.1 Alternatives Considered
Section 5 identified 7 minimum design cnteria to be considered when retrofitting the existing
influent flow split box for the primary clarifiers at the Yakima Regional WWTP. Two
alternatives, shown in Figures 6-4 and 6-5, have been evaluated to meet the minimum design
requirements outlined:
> Retain the existing influent flow split box with automated scum removal.
> Install a new influent flow split box with scum removal, which will eliminate scum
removal requirements at the existing unit.
6.8.1.1.1 Retain Existing Flow Split Box with Automated Scum Removal
Under this alternative, 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 pnmary influent flow
split channels. Each of these troughs will include a 30 IN 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 have 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. This alternative
includes new replacement sluice gates in the existing split box.
Figure 6-4. Retain Existing Primary Influent Flow Split Box
PRIMARY EFFLUENT PRIMARY CLARIFIERS TRICKLING FILTERS
FLOW SPLIT BOX
SCUM
REMOVAL
E RATION BASINS SECONDARY CLARIFIERS
6.8.1.2 Install New Influent Flow Split Box
Under this alternative, a new primary influent flow split box would be constructed. The split box
would be located between the existing influent channels approximately 5 feet south of the
existing Influent Building. The two existing wastewater influent channels would be modified to
direct flows into the new split box where influent would upflow over flow split weirs to the
clarifiers. The flow split box would include isolation slide plates in conjunction with the split
HDR ENGINEERING, INC
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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DRAFT
weirs to enable dewatering of the influent pipelines and isolation of the primary clarifiers from
service. The existing flow split and isolation sluice gates would be removed under this
alternative. The two existing outlet channels, along with two new pipelines, will transport the
flow from the new split box overflow to the existing split box, and on to the primary clarifiers.
Flows will be diverted directly through the existing flow split box en route to the primary
clarifiers to eliminate scum accumulation and allow scum removal to occur at the primary
clarifiers.
Figure 6-5. Install New Primary Influent Flow Split Box
NEW PRIMARY DEMOLISH EXISTING PRIMARY CLARIFIERS
FLOW SPLIT SOX FLOW SPLIT BOX
TRICKLING FILTERS AERATION BASINS SECONDARY CLARIFIERS
• 6.8.2 Alternatives Evaluation
➢ Retrofitting the existing split box with automated scum removal units and new sluice
gates will provide a cost effective means of resolving the scum removal problem.
➢ The sluice gates controlling flow to each primary clarifier leak, which makes isolation of
the primary clarifiers difficult. Both alternatives evaluated will eliminate this problem.
➢ Replacement of the existing split box with a new unit will provide an effective means of
splitting the flows to the four primary clanfiers.
➢ Both alternatives utilize proven technology. The new split box alternative is less
sophisticated (without the automated scum removal gates) and therefore offers some
reliability advantage.
➢ Constructibility of both alternatives is challenging. The split box rehabilitation option
requires removal of influent channels or influent bypass pumping to complete the work.
Construction of a new split structure will require similar efforts to enable connection of
influent channels to the new split structure.
•
The opinion of probable costs of the primary treatment split box alternatives are presented in
Table 6-8. Both systems have similar operation requirements. Some additional maintenance
may be required for the additional scum skimming equipment with the existing split box. The
estimated additional costs are considered to be minimal.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 20
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Table 6-8. Opinion of Probable Cost for the Primary Treatment Split Box Alternatives
Unit Opinion of Probable Cost (to Build -out)
Retain Existing Box
Install New Box
Facility Construction and Retrofits $182,000 $329,000
Electrical (15%) $27,300 $49,400
UC (7 %) $12,700 $23,000
Site Work and Yard Piping (20%) $36,400 $65,800
Subtotal Costs $258,400 $467,200
Contractor Overhead and Profit (15%) $38,800 $70,100
Subtotal $297,200 $537,300
Contingency (20%) $59,400 $107,500
Subtotal $356,600 $644,800
Sales Tax (8%) $28,500 $51,600
Subtotal $385,100 $696,400
Engineering, legal and fiscal (25%) $96,300 $174,100
Total Opinion of Probable Cost $481,400 $870,500
6.8.3 Recommendations
In order to split the flow equally, direct solids uniformly to all clarifiers, and collect scum from
the influent stream, a new flow split box is recommended.
6.9 Trickling Filter System Alternatives
The trickling filters consist of a bed of highly permeable microorganisms attached to rock
medium that wastewater is trickled through. Two 170 -foot diameter Trickling Filters are
available at the Yakima Regional WWTP. Wastewater from the primary clarifiers enters the
trickling filter pumping station where it is mixed with trickling filter re -circulation flow before
being pumped to the trickling filters. Two alternatives have been selected to refine trickling filter
performance.
6.9.1 Alternatives Considered
Section 5 identifies 6 minimum design criteria to be considered when retrofitting the existing
trickling filters at the Yakima Regional WWTP. Two options have been examined for the
tnckling filters:
➢ Install plastic media in the trickling filters.
➢ Improve ventilation with enhanced forced ventilation in the trickling filters.
6.9.1.1 Install Plastic Trickling Filter Media
Plastic trickling filter media provides a lightweight alternative to conventional rock media which
has the disadvantage of occupying the majority of the filter bed, reducing the void spaces, and
limiting the surface area per unit volume for biological growth. Plastic trickling filter media
normally has a greater surface area per unit volume and creates a larger percentage of free space
in the filter. One advantage to replacing the trickling filter media is additional loading can be
placed on the trickling filters. Currently, the existing trickling filter media may be loaded to
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000 Page 21
•
DRAFT
approximately 50 lb/cf/d (average conditions). Changing the media to high density plastic media
will increase performance to approximately 127 lb/cf/d. This alternative would be implemented
with other activated sludge alternatives presented in paragraph 6.10. By maximizing the capacity
and capability of the tnckling filter system, required capacity expansion of the activated sludge
system can be reduced.
6.9.1.2 Install Forced Ventilation in the Trickling Filters
Enhanced forced ventilation in the trickling filters at the Yakima Regional WWTP will help to
circulate air through the filters and improve the removal of BOD by supplying additional oxygen
to the biological processes.
The minimum calculated air requirement at current trickling filter loadings is approximately 0.67
SCFM/SF of filter area, or 30,400 SCFM for both trickling filters (15,200 SCFM each). This
compares to the current ventilation rate of 24,000 SCFM provided to each trickling filter.
If the trickling filters were loaded to their ultimate capacity of 127 lb/cf/d with plastic media, the
air requirement would increase to 1.75 SCFM/SF or approximately 80,000 cfm for both tricking
filters (40,000 SCFM each unit). This would require installation of recirculation fans on each
filter with an equivalent capacity to the current air handling systems.
This alternative would be implemented with other activated sludge alternatives presented in
paragraph 6.10. By maximizing the capacity and capability of the trickling filter system with
these modifications, required capacity expansion of the activated sludge system can be
minimized.
This alternative would include installation of recirculation ventilation on each trickling filter of
approximately 20,000 SCFM each.
6.9.2 Alternatives Evaluation
➢ Plastic tnckling filter media performance has shown that they are easier to clean, less
prone to clogging or channeling, and do not require the support structure that rock media
does.
➢ The benefits that forced ventilation provides for the attached growth process warrant its
consideration.
➢ The benefit of implementation of these alternatives is the possible corresponding
reduction in expansion requirements of the activated sludge system.
➢ In rehabilitating the trickling filters, new rotary distributors would be provided for
enhanced flow distribution. The existing rotary distributors were installed in 1965 with
repairs and modification in 1982 and 1990. The Facility Construction and Retrofits cost
for the new rotary distributors is $350,000 (without markups) and will be added to all
alternatives.
The opinion of probable costs of the tnckling filter treatment alternatives are presented in Table
• 6-9.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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Table 6-9. Opinion of Probable Cost for the Trickling Filter Alternatives
Unit
Opinion of Probable Cost (to Build -out)
Plastic Media Addition
Forced Ventilation
Rotary Distributors
Facility Construction and Retrofits
Electrical (15%)
I/C (7 %)
Site Work and Yard Piping (20%)
Subtotal Costs
Contractor Overhead and Profit (15%)
Subtotal
Contingency (20%)
Subtotal
Sales Tax (8%)
Subtotal
Engineering, legal and fiscal (25%)
$760,000
$0
$0
$152,000
$912,000
$136,800
$1,048,800
$209,800
$1,258,600
$100,700
$1,359,300
$339,800
$403,000
$60,500
$28,200
$80,600
$572,300
$85,800
$658,100
$131,600
$789,700
$63,200
$852,900
$213,200
$350,000
$0
$0
$70,000
$420,000
$63,000
$483,000
$96,600
$579,600
$46,400
$626,000
$156,600
Total Opinion of Probable Cost
$1,699,100
$1,066,100 $782,500
6.9.3 Recommendations
Replacing the existing trickling filter rock media with plastic media and adding more ventilation
will provide additional capacity for the filters. These retrofits are beneficial to the operation of
the trickling filters and will heighten the performance and capacity for future flow and loadings.
The benefits of enhancing trickling filter performance are weighed against other unit process
expansion alternatives presented in paragraph 6.10 — Activated Sludge Alternatives.
Recommendations regarding the trickling filters are presented in paragraph 6.10.
6.10 Activated Sludge System Alternatives
The activated sludge system at the Yakima Regional WWTP utilizes the biological processes to
remove carbonaceous BOD, ammonia, nitrate and phosphorus. In developing alternatives for the
activated sludge system, it was recognized that the existing trickling filer system must be
evaluated in conjunction with this activated sludge unit process because of the integral process
relationship of these facilities. The activated sludge system was defined to include facilities from
primary effluent distnbution through secondary clarification.
6.10.1 Alternatives Considered
Section 5 identifies 26 minimum design cntena to be considered when retrofitting the activated
sludge facilities at the Yakima Regional WWTP. Seven alternatives were retained for evaluation
to meet the minimum design requirements outlined. These alternatives are grouped into three
general categories as listed below:
> RAS/WAS Pumping:
• Replace existing RAS/WAS pumping.
• Retain existing pumping station and construct separate pumping station for new
process units.
➢ Secondary Clarifiers:
• Retrofit existing trickling filter clarifier.
• Construct new secondary clanfier.
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CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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➢ Aeration Basins/Secondary Treatment:
• Upgrade existing aeration basins, build equivalent third aeration basin train, upgrade
trickling filters for higher organic loading.
• Upgrade existing aeration basins, build equivalent third aeration basin train and
increase process MLSS to meet design loadings.
• Upgrade existing aeration basins, build new aeration basin capacity.
6.10.1.1 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 2020 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.
The alternatives for providing additional aeration basin and secondary clarifier capacity would
require connection of these new facilities into the existing pumping stations. Site piping and
electrical utility congestion in the vicinity of the existing RAS Pumping Station prohibit the
construction of needed return pumping flow metering enhancements, aeration basin effluent flow
split (to accommodate the additional secondary clarifier), and WAS and secondary scum
pumping.
There appears to be two feasible options for RAS and WAS pumping. These alternatives would
be installed in conjunction with additional aeration basin and secondary clarifier capacity
including 1) installation of new RAS and WAS facilities to support only the new aeration basin
and secondary clarifier units; and 2) installation of a new RAS/WAS Pumping Station to support
both new and existing aeration basins and secondary clarifiers. Preliminary layouts of these
facilities are presented in conjunction with aeration basin layouts later in this section.
Replace Existing Pumping Station
Under this alternative, the existing RAS and WAS pumping facilities would be replaced by a
new RAS/WAS Pumping Station to be located to the southeast of the existing aeration basin
complex. The new RAS/WAS pumping station would be configured to serve the existing
Aeration Basins No. 1 through No. 4, existing Secondary Clarifiers No. 1 and No. 2 and a future
Aeration Basin and Secondary Clarifier No. 3. The new pumping station would be constructed
as common -wall construction with the secondary clarifier expansion. A portion of the north
supernatant lagoon would be used for installation of the new facilities.
The pumping station would be sized for 100 percent RAS return flows of 17.94 mgd (12,500
gpm) at year 2020 design condition with the ability to expand to ultimate build -out with average
flows of 22.37 mgd. RAS would be pumped from each secondary clarifier into a common RAS
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000 Page 24
DRAFT
header and introduced into the process at a new aeration basin influent flow split structure. New
RAS and secondary scum pipelines would be installed in the existing secondary clarifiers.
Retain Existing Pumping Station and Construct a Separate Pumping Station for
New Process Units
Under this alternative, the existing RAS/WAS pumping units would remain in service to support
the existing aeration basins and secondary clarifiers. Upon installation of new aeration basin
capacity and a third secondary clarifier, a new pumping station would be constructed to
accommodate the new process units. The existing RAS pumping units would be replaced with
new equipment.
The new RAS/WAS Pumping Station would be constructed adjacent to the new Secondary
Clarifier using common -wall construction. The pumping station would be sized to match the
capacity of an aeration basin expansion of 3.2 mgd (2,200 gpm). The RAS pumps and the WAS
pumps would be provided and have the ability to meet a 100 percent RAS return rate condition.
The facility also would have the ability to be expanded to serve a fourth secondary clarifier in the
future.
Alternatives Evaluation
➢ Both alternatives evaluated would address all design cnteria presented in Section 5 and
would be technically equivalent.
➢ Replacement of the existing RAS pumping facilities would resolve current problems with
control of the RAS pumping flow split.
➢ The installation of aeration basin effluent flow split facilities will require additional
construction phasing for the alternative where the existing RAS pumping station will be
maintained, making the replacement alternative easier to construct.
➢ Installation of a new RAS pumping facility to support all secondary treatment process
units will enable better system redundancy and reliability.
➢ Operations and maintenance for the alternative that replaces existing pumping systems
would be less involved since all operations would be focused on a single facility versus
two separate facilities.
The opinion of probable costs of the RAS/WAS pumping alternatives are presented in Table 6-
10. This opinion of probable cost is based on providing the capacity for year 2020 conditions
with the ability to easily expand to ultimate build -out.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 25
•
•
DRAFT
Table 6-10. Opinion of Probable Cost for RAS/WAS Pumping Alternatives
Unit
Opinion of Probable Cost (to Build -out)
New RAS/WAS Station
Existing RAS/WAS Pumping
Station
Facility Construction and Retrofits
$631,000
$488,000
Electrical (15%)
$94,700
$73,200
I/C (7 %)
$44,200
$34,200
Site Work and Yard Piping (20%)
$126,200
$97,600
Subtotal Costs
$896,100
$693,000
Contractor Overhead and Profit (15%)
$134,400
$104,000
Subtotal
$1,030,500
$797,000
Contingency (20%)
$206,100
$159,400
Subtotal
$1,236,600
$956,400
Sales Tax (8%)
$98,900
$76,500
Subtotal
$1,335,500
$1,032,900
Engineering, legal and fiscal (25%)
$333,900
$258,200
Total Opinion of Probable Cost
$1,669,400
$1,291,100
Recommendations
Replacing the existing RAS/WAS pumping facilities would offer operations and maintenance
advantages including better flow rate control, better system redundancy, and more convenient
maintenance and operation from a single facility. The installation of a new RAS pumping station
with common discharge header would resolve problems with flow split control from the
secondary clarifiers experienced with the existing system. Expansion of the existing aeration
basin system may result in the development of three separate aeration basin treatment trains using
the existing aeration basin cells and a new third basin cell. Based on this configuration as the
preferred alternative for the aeration basin unit process, construction of a new RAS/WAS
Pumping Station that will accommodate all three aeration trains will provide for better operations
control and flexibility.
Since problems exist with the control of flow split from the existing RAS pumping station, the
implementation of construction of new facilities while maintaining the existing RAS pumping as
an integral part of the future facility, and the construction of a new RAS/WAS pumping facility,
has distinct operation and maintenance advantages. Construction of a new RAS/WAS pumping
station replacing the existing facilities is recommended.
6.10.1.2 Secondary Clarifiers
Section 5 identifies the need for an additional secondary clarifier to meet WDOE redundancy
criteria. Two alternatives were developed for providing the needed additional secondary clarifier
capacity. These included rehabilitation of the existing Trickling Filter Clarifier and construction
of a new 140 -foot Secondary Clarifier.
Retrofit Existing Trickling Filter Clarifier
III
The existing 170 -foot diameter Trickling Filter Clarifier would be retained under this alternative.
The clarifier mechanism would be replaced, a new basin dewatering system would be added, and
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CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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DRAFT
the basin launders and effluent weirs would be raised to enable the use of this clarifier with the
existing hydraulic profile without adding effluent pumping. New basin RAS and WAS piping
would be installed to work with RAS/WAS pumping processes planned under other alternatives.
The basin retrofit would raise the clarifier launder approximately 1 foot to a weir elevation of
approximately 1001.0. This would result in a revised clarifier side water depth of 9 feet. This is
compared to the existing Secondary Clarifiers No. 1 and 2 that have a side water depth of 15 feet.
Under this alternative, the slide gate in the secondary diversion box that directs flow for this
clarifier leaks and would be replaced.
Construct a New Secondary Clarifier
Under this alternative, a new 140 -foot diameter secondary clarifier would be constructed similar
to the two existing units. To avoid layout issues involved with a power service line transecting
the Yakima Regional WWTP site, the proposed location of the new Secondary Clarifier would be
southwest of existing Secondary Clarifier No. 2, located on a portion of the existing north
Supernatant Lagoon. The new clarifier would be installed with effluent launder algae sweeps,
density current baffles, large center feed well and 15 -foot side water depth.
Alternatives Evaluation
➢ Retrofitting the existing trickling filter clarifier for service with the aeration basins will
require significant yard piping modifications. Construction phasing would be similar for
both alternatives.
> Performance of the trickling filter clarifier would be inferior to the existing secondary
clarifiers due to the shallow side water depth associated with this unit.
➢ Clarifier detention time for the larger 170 foot diameter Trickling Filter Clarifier may
exceed recommended values during certain low flow periods.
> Secondary influent flow split operation will be more complicated if the larger trickling
filter clarifier is placed into operation.
➢ A separate RAS/WAS pumping facility for the existing trickling filter clarifier would
increase process control complexity and operations and maintenance expense of the
separate facility.
The opinion of probable construction costs for the secondary clarifier alternatives are presented
in Table 6-11. Because both alternatives have similar operation and maintenance requirements,
only facility opinion of probable construction costs are presented.
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CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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Table 6-11. Opinion of Probable Cost for Secondary Clarifier Alternatives
Unit
Opinion of Probabl
e Cost (to Build -out)
Trickling Filter Clarifier
Rehabilitation)
New Secondary Clarifier
Facility Construction and Retrofits $1,146,000
Electrical (15% New; 20% Exist) $219,200
UC (7 %) $80,200
Site Work and Yard Piping $276,500
(20% New; 25% Exist)
Subtotal Costs $1,759,400 $1,721,900
Contractor Overhead and Profit (15%) $263,900 $258,300
Subtotal $2,023,300 $1,980,200
Contingency (20%) $404,700 $396,000
Subtotal $2,428,000 $2,376,200
Sales Tax (8%) $194,200 $190.100
Subtotal $2,622,200 $2,566,300
Engineering, legal and fiscal (25%) $655,600 $641,600
Total Opinion of Probable Cost $3,277,800 $3,207,900
$1,239,000
$185,900
$86,700
$247,800
IA separate RAS/WAS Pumping station is required for this alternate which is reflected in the opinion of probable cost
shown ($200,000).
Recommendations
Construction of a new Secondary Clarifier, which provides a deeper side water depth and
hydraulic match to the existing secondary clarifiers is recommended. The clarifier would be
located west of the existing power utility line in close proximity to Secondary Clarifier No.2 and
the planned aeration basin expansion. The clarifier would require the use of a portion of the
north Supernatant Lagoon land area for construction.
6.10.1.3 Aeration Basins
Effluent from the primary clarifiers and/or the trickling filters is currently directed to the four
rectangular aeration basins. Influent flow may be mixed with return activated sludge either
before, or upon entering, the aeration basins, depending on the mode of operation in the aeration
basins. Flow may exit from any of the aeration basins, depending on the mode of operation.
Section 5 indicates that the aeration basins are at or near capacity when the trickling filters are
loaded at a conventional loading of 50 lb/kcf/d (average conditions), and the damaged Aeration
Basin No. 4 is out of service. If Aeration Basin No. 4 were placed back into service,
approximately 25 percent additional capacity remains. This would provide sufficient capacity up
to the year 2010 conditions, based upon population projections presented in Section 4 and a
MLSS concentration of 2,200 mg/1.
Section 7 presents the structural evaluation of Aeration Basin No. 4, and makes
recommendations for repair of the basin floor. In addition, the report also recommends that the
remaining three basins be evaluated for the need for similar repairs. During the treatment system
capacity evaluation, recommendations were made to conduct additional oxygen uptake rate
(OUR) testing for the aeration basin diffusers. Previous testing indicated an OUR of 52 mg/L/h
is achievable. Subsequent to this testing, the City has experienced problems with diffuser grid
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CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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DRAFT
supports and has removed and re -fired some of the ceramic aeration diffusers. These issues may
have impacted the OUR rate used for analysis of future options.
The aeration basin analysis is heavily dependent upon the mode of operation of the tnckling filter
system. All aeration basin alternatives also involve specific actions to the trickling filter systems.
The system capacity analysis used a limit on the MLSS concentration within the aeration basins
of 2,200 mg/L. This was based upon operating experience with the existing basins.
Expansion of the aeration basin process units may be accomplished by adding more aeration
basin volume, increasing capacity of the existing basins by fixing hydraulic bottlenecks,
increasing the allowable MLSS concentration, or by delivering more loading to the trickling filter
system. The following presents the most viable alternatives identified for providing additional
capacity of the aeration basin system.
Upgrade Existing Aeration Basins, Build Equivalent Third Aeration Basin
Treatment Train, Upgrade Trickling Filters for Higher Organic Loading
Under this alternative, the existing aeration basin complex would be improved by adding a new
influent flow split structure, a new effluent flow split structure and configuring the aeration
basins to operate as two parallel treatment trains (Basins No. 2 and No. 1, Basins No. 3 and No.
4). See Figure 6-6. In addition to required piping modifications, the basin aeration grid supports
would be repaired where needed. The new aeration basin split structure would be followed by
dedicated anoxic selector zones constructed for an average hydraulic retention time of 12-15
minutes. The selector basin sizes are 56,000 gallons each for a total of 167,000 gallons to meet
year 2020 conditions.
The existing aeration basin volume is approximately 4.2 million gallons. If the basins were
configured to operate as two treatment trains, each train would then be sized at 2.1 million
gallons. To provide expansion of the aeration basin system in a logical increment, this
alternative utilizes a third aeration basin treatment train sized at 2.1 million gallons. The new
basin would be constructed to the south of the existing aeration basins in a portion of the north
Supernatant Lagoon. The basin would be configured in a similar manner to the existing basins,
and would be connected to the new aeration basin flow spit box, anoxic selector basin, and
aeration basin effluent flow split box.
In order to provide sufficient aeration basin capacity for year 2020 and ultimate build -out
conditions, and hold the MLSS concentration to no more than 2,200 mg/L, expansion of the
aeration basin volume would be 2.3 and 3.2 million gallons respectively. The 2.1 million gallon
expansion proposed with this alternative is insufficient to meet ultimate loading conditions at a
MLSS concentration of 2,200 mg/L. Therefore, this alternative would also include an increase in
loading to the tnckling filters above 50 lb BOD/kcf/d. This would allow operations to maintain
MLSS concentrations below 2,200 mg/L. To increase the loading to the tnckling filters above
this level, replacement of the existing rock media with plastic media, as outlined in paragraph
6.9, is recommended. Sufficient aeration blower capacity is available to serve the existing and
new aeration basins under this alternative.
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CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 29
•
•
•
DRAFT
Alternative Summary
➢ Installation of new aeration basin influent and effluent flow split boxes.
➢ Installation of three (equal -sized) aeration basin anoxic selector basins (56,000 gallons
each).
➢ Rehabilitation of existing aeration basins including floor repairs, diffuser grid support
repairs, and piping for operation as two parallel treatment trains.
➢ Construction of a new 2.1 million gallon aeration basin, and associated piping and
aeration grid.
➢ Connection of the new aeration basin to the existing blower system.
➢ Replacement of the tnckling filter rock media with new high efficiency plastic media and
forced ventilation of filters.
➢ Replacement of the rotary distributors in each trickling filter.
Figure 6-6. Construct New 2.1 MG Aeration Basin and Add Plastic Media to
Existing Trickling Filters
TRICKLING FILTERS
WITH PLASTIC MEDIA
ANOXIC SELECTOR
INFLUENT FLOW
SPLIT BOX
ANOXIC SELECTOR
AERATION
BASIN NO 2
AERATION
BASIN NO 1
AERATION
BASIN NO 3
AERATION
BASIN NO 4
NEW2 1, d AERATION BASIN
FUTURE
EFFLUENT FLOW
SPLIT BOX
SECONDARY
CLARIFIER NO 1
SECONDARY
CLARIFIER NO 2
NEW SECONDARY
CLARIFIER
Upgrade Existing Aeration Basins, Build Equivalent Third Aeration Basin
Treatment Train, Increase Basin MLSS Concentration Above 2,200 mg/L.
This alternative is similar to the previous alternative, except that the modifications to the
trickling filter media would not be implemented. See Figure 6-7. To provide for greater organic
treatment capacity to meet ultimate loading conditions, the MLSS concentrations within the
aeration basins would be increased to slightly above 3,000 mg/L. Increasing the MLSS
concentration would place the unit process into an aeration controlled condition versus solids
controlling. This would heighten the importance of field testing the oxygen uptake rate (OUR)
recommended in Section 5. Eliminating the trickling filter modifications and increasing MLSS
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CITY OF YAKIMA
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concentrations would require accurate control of basin RAS flow rates, and the use of the
proposed anoxic selectors to operate in this high rate mode of operation. A new fifth aeration
blower may be required under this alternative.
Alternative Summary
➢ Installation of new aeration basin influent and effluent flow split boxes.
➢ Installation of three equal size aeration basin anoxic selector basins (56,000 gallons each).
➢ Rehabilitation of existing aeration basins including floor repairs, diffuser grid support
repairs, and piping for operation as three parallel treatment trains.
➢ Construction of a new 2.1 million gallon aeration basin treatment train and associated
piping and aeration grid.
➢ Connection of the new aeration basin to the existing blower system.
➢ Installation of a fifth aeration blower and associated vanable frequency drive.
➢ Modification of process controls and RAS pumping to enable an increase in MLSS
concentration to approximately 3,000 mg/L.
➢ Although this alternate does not include replacement of the rock media in the trickling
filters, or the forced ventilation of the filters, replacement of the rotary distributors in
each trickling filter will be required to maintain current operation.
Figure 6-7. Construct New 2.1 MG Aeration Basin and Increase MLSS
Concentration Above 2,200 mg/I
TRICKLING FILTERS INFLUENT FLOW
SPLIT BOX
I • �
ANOXIC SELECTOR
ANOXIC SELECTOR
AERATION
BASIN NO 2
AERATION
BASIN NO 1
AERATION
BASIN NO
AERATION
BASIN NO 4
EFFLUENT FLOW
SPLIT BOX
SECONDARY
CLARIFIER NO 1
SECONDARY
CLARIFIER NO 2
ANOXIC SELECTOR
NEW 2 InOE AERATION BASIN
NEW SECOND RY
CLARIFIER
FUTURE
_ FUTURE
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CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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Upgrading Existing Aeration Basins and Build New 3.2 Million Gallon Aeration
Basin
Under this alternative, the aeration basin influent and effluent boxes and selector basins would be
constructed. In lieu of three (equal -sized) treatment trains, the new third aeration basin and
associated anoxic selector basin would be sized to handle loadings to ultimate build -out. See
Figure 6-8. An aeration basin expansion of 3.2 million gallons and anoxic selector basin of
85,000 gallons would be required. The basin MLSS concentrations would be held to 2,200 mg/L
and loading to the trickling filters would be set at 50 lb BOD/kcf/d (approximately 35 percent of
flow directed to the trickling filters). Aeration required to meet maximum day or maximum
month conditions are 28,800 SCFM and 22,500 SCFM. The existing aeration blowers have a
capacity of 4,800 SCFM each for a total aeration capacity of 19,200 SCFM and firm aeration
capacity of 14,400 SCFM with one unit out of service. To meet the required aeration needs for
this alternative, a new blower system and blower building would be required to serve the new
basin since insufficient space is available to install multiple new blowers within the existing
blower gallery.
TRICKLING FILTERS
Figure 6-8. Construct New 3.2 MG Aeration Basin
ANOXIC SELECTOR
INFLUENT FLOW
SPLIT BOX
ANOXIC SELECTOR
Alternative Summary
FUTURE
AERATION
BASIN NO 2
AERATION
BASIN NO 1
AERATION
BASIN NO 3
AERATION
BASIN NO 4
NEW 3 2NQd AERATION BASIN
FUTURE
EFFLUENT FLOW
SPUR BOX
SECONDARY
CLARIFIER NO 1
SECONDAR
CLARIFIER NO 2
NEW SECONDARY
CLARIFIER
➢ Installation of new aeration basin influent and effluent flow split boxes.
➢ Installation of two anoxic selector basins (56,000 gallons) for the existing aeration basins,
and one anoxic selector basin (85,000 gallons) for the new aeration basin.
➢ Rehabilitation of existing aeration basins including floor repairs, diffuser grid support
repairs, and piping for operation as three parallel treatment trains.
➢ Construction of a new 3.2 million gallon aeration basin, and associated piping and
aeration grid.
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IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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DRAFT
➢ Connection of the existing aeration basins to the new blower system.
➢ Relocation of existing blower system with installation of 3 new additional blowers in a
new blower building.
➢ Although this alternate does not include replacement of the rock media in the trickling
filters, or the forced ventilation of the filters, replacement of the rotary distributors in
each trickling filter will be required to maintain current operation.
6.10.2 Alternatives Evaluation
➢ All alternatives evaluated would address the minimum design criteria presented in
Section 5.
➢ Expansion of the aeration basin capacity in increments (2.1 mg) to provide for three
equivalent activated sludge treatment trains has distinct operations advantages including
system redundancy, flow split simplicity, and less operation complexity.
➢ Construction implementations of all three alternatives have similar project phasing
requirements associated with the installation of new flow split structures.
➢ Operation of the aeration basins at MLSS concentrations above 2,200 mg/L would exceed
current mass limits used by operations staff. Installation of improved RAS flow rate
control, process flow split, and aeration basin anoxic selectors would enable changing the
processes to higher MLSS concentrations.
➢ Construction of the aeration basin expansion to 2.1 million gallons, and operation of the
activated sludge system at higher MLSS concentrations, has a clear capital cost
advantage. Expanding the basin to match the sizing of existing basins will result in a
well-balanced facility layout, will require less immediate capital investment, and allows
for future facility expansion in a similar modular format.
➢ Construction of anoxic selector basins will accommodate a denitrification retrofit of the
aeration basins in the future. A fourth aeration basin treatment train and basin anoxic
zone would be added in the future.
The opinion of probable costs of the aeration basin system alternatives are presented in Table 6-
12. Because all the alternatives have similar operation and maintenance requirements, only
facility opinion of probable construction costs are presented. The alternative cost estimates
include costs associated with installation of yard piping to connect the aeration basins to new
influent and effluent flow split structures. In addition, each alternative cost estimate also
includes costs associated with the anoxic selector basins for each alternative. Since the aeration
basin influent flow split and effluent flow split structures are planned for all alternatives
evaluated, the costs associated with these structures are included as a "feature" and are presented
later in this memorandum.
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CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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Table 6-12. Opinion of Probable Cost for Aeration Basin System Alternatives
Unit
Opinion of Probable Cost (to Ultimate)
New 2.1 mg Basin &
Trickling Filter Media
Replacement
New 2.1 mg Basin and
High MLSS Concentration
New 3.2 mg Basin
Aeration Basin Construction and Retrofits
$2,588,000
$2.995,000
$4,190,000
Trickling Filter Construction & Retrofits
$1,513,00012
$350,0002
$350,0002
Subtotal Aeration Basin/TF Retrofits
$4,101,000
$3,345,000
$4,540,000
Electrical (15%) (AB & FV only)
$448,700
$449,300
$628,500
IIC (7 %) (AB & FV only)
$209,400
$209,700
$293,300
Site Work and Yard Piping (20%)
$820,200
$669,000
$908,000
Subtotal Costs
$5,579,300
$4,673,000
$6,369,800
Contractor Overhead and Profit (15%)
$836,900
$701,000
$955,500
Subtotal
$6,416,200
$5,374,000
$7,325,300
Contingency (20%)
$1,283,200
$1,074,800
$1,465,100
Subtotal
$7,699,400
$6,448,800
$8,790,400
Sales Tax (8%)
$616,000
$515,900
$703,200
Subtotal
$8,315,400
$6,964,700
$9,493,600
Engineering, legal and fiscal (25%)
$2,078,300
$1,741,200
$2,373,400
Total Opinion of Probable Cost
$10,394,300
$8,705,900
$11,867,000
'New Plastic Media and forced ventilation from Table 6-9
2New rotary distributors for trickling filters.
The results of Table 6-12 show there is an initial cost savings associated with installation of the
smaller aeration basin expansion, and operating the basins in a high rate mode (MLSS >2,200
mg/L) at year 2020 conditions and beyond. The opinion of probable cost for the replacement of
the trickling filter distributors is $782,500 and has been identified as a facility Key Feature
project.
6.10.3 Recommendations
Construction of a 2.1 million gallon aeration basin expansion is recommended. This alternative
offers advantages in addition to lower capital costs. Construction of aeration basin volume to
provide three equivalent capacity treatment trains provides uniform redundancy, easier flow split
control, straight forward process control, and flexibility for future expansion should
denitrification be required. With the initial construction of the 2.1 million gallon aeration basin,
the facilities will have the option in the future to either change out the trickling filter media to
plastic, or operate the aeration basin at a high MLSS concentration. If the trickling filter media is
replaced, it is also recommended that the forced ventilation system improvements be completed
to maximize the benefits of the plastic media. Operation of the aeration basins at higher MLSS
concentrations will require installation of one additional aeration blower. Because the aeration
basin oxygen uptake rate (OUR) would be critical in determination of final design MLSS
concentrations, the aeration basin testing recommended as part of Section 5 should be performed.
In maintaining compliance with current regulations, and to provide for the installation of the new
secondary clarifier and new RAS/WAS pumping station, a new influent flow split structure, a
new effluent flow split structure, configunng the existing aeration basins to allow operation as
two parallel treatment trains, and addition of dedicated anoxic selector cells (56,000 gallons
each) is recommended as a near term improvement. The opinion of probable costs of these
improvements is $2,480,000. By constructing these improvements as an independent project
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from the construction of a new future 2.1 million gallon aeration basin, the opinion of probable
cost for the future aeration basin, anoxic selector basin, and appurtenances is $4,366,600.
• 6.11 Disinfection Alternatives
•
•
Disinfection is provided for the liquid stream of the wastewater treatment plant. The existing
disinfection system consists of gaseous chlorination and gaseous sulfuration for de -chlorination.
The existing disinfection system has sufficient capacity for average annual conditions for year
2020. 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-place at the storage facilities, personnel and public safety 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.
6.11.1 Alternatives Considered
Five options have been examined for disinfection at the Yakima Regional WWTP. They
include:
> Maintain the existing chlorination/dechlonnation 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 medium pressure ultraviolet light
disinfection.
> Replace the chlorination system with closed channel medium pressure ultraviolet light
disinfection.
Maintain Existing Chlorination/Dechlorination System
The current chlorination system consists of two chlorine contact chambers capable of supporting
the 2020 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 new chlorine
scales that have better readout resolution, replacement of the CL2 and SO2 leak detectors,
addition of gas calibration equipment, and relocation of sampling equipment.
Replace Chlorination System with Hypochlorite/Dechlorination System
Alternative wastewater disinfection methods have been used more frequently in recent years,
replacing traditional gaseous chlonne and sulfur dioxide systems. As a result, liquid chemical
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systems using sodium hypochlorite as the chlonnating 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 that 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 chlonne. Special handling and storage issues are
required.
Sodium hypochlorite is inherently unstable and loses about one-half of its strength every 100
days as 21°C (70°F). 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 (chlonne demand), and other plant -specific
variables.
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.
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DRAFT
Both sodium hypochlorite and sodium bisulfite are typically delivered in 500 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 by
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 chlonde (CPVC).
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 fee 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 momtonng,
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, and
relocation and improvements to the sampling equipment 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 6-9. For evaluating the available disinfection alternatives, it is anticipated that the
systems would be configured to accommodate the ultimate build -out conditions of 47.4 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 17.94 mgd (Year 2020 flow condition) is utilized.
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Figure 6-9. Ultraviolet Disinfection Alternatives
PRIMARY CLARIFIERS TRICKLING FILTERS
1 THE BAFFLES W ILL BE REMOVED FROM THE CHLORINE CONTACT CHAMBERS
PRIOR TO THE INSTALLATION OF ULTRAVIOLET DISINFECTION
AERATION BASINS SECONDARY CLARIFIERS ULTRAVIOLET
DISINFECTION
Replace Chlorination System with Open Channel Low Pressure
Ultraviolet Light Disinfection
'XXRIVER
This alternative would include removal of the gaseous chlorination and dechlonnation 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. The opinion of probable costs utilize a vertical
lamp arrangement. Two parallel UV channels would be installed, each with a peak flow capacity
of approximately 24.0 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 180 gallons per minute of wastewater. Based on average transmissivities that would be
encountered at Yakima, an estimated 1,400 low pressure lamps would be required to handle the
peak flow condition of 47.4 mgd at buildout.
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 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 2,300 gallons per minute, significantly greater than low pressure lamps. As a
result, only approximately 120 medium pressure lamps would be required to accommodate the
ultimate build -out peak flow condition of 47.4 mgd. Since the medium pressure systems involve
additional headloss with the horizontal, channelized flow pattern, it has been anticipated that a
minimum of 4 parallel channels would be installed. Level control facilities, equipment
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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. Because this technology is generally applied to
smaller flow applications (<10 mgd), equipment is more readily available in modules up to
approximately 5 mgd. To accommodate the closed channel technology at Yakima, it has been
anticipated that eight parallel flow pipelines would be installed in the existing chlonne 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. An open
air canopy would be installed over the UV gallery to protect the UV equipment from the weather.
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.
6.11.2 Alternatives Evaluation
➢ Based upon projected flows and loadings presented in Section 5, the chlorine contact
channels have sufficient capacity to year 2020 average annual flow conditions of 17.94
mgd, and peak flow conditions of 38.01 mgd. The existing chlorine contact channels
require some retrofits. There is growing public concern dealing with the safety of liquid
and gas chlorine.
➢ Evaluation of alternatives will address the ultimate build -out condition of 47.4 mgd for
capital costs. Operation and maintenance evaluation is based on year 2020 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.
➢ 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. Because enclosed channel systems are generally
used for lower -flow applications, equipment designs have not been developed for larger
flow applications. As such, this technology is less proven than low pressure or open
channel medium pressure systems.
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➢ 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.
➢ Electrical consumption for medium pressure systems is slightly lower than low pressure
systems.
➢ Implementation of the open channel medium pressure systems is easier than low pressure
systems because less channel modifications and infrastructure improvements are required
for medium pressure systems.
➢ 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.
Opinions of probable cost were developed for each of the disinfection alternatives. These are
summarized in Table 6-13. These estimates are based on initially providing the capacity needed
for year 2020 and then expanding the facility for ultimate peak flow conditions of 47.4 mgd.
Initial channel modifications are sized to accommodate installation of the equipment for ultimate
conditions.
Table 6-13. 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
Medium
Pressure
Closed Channel
Medium
Pressure
Facility Construction and Retrofits
$142,000
$270,000
$1,205,000
$1,486,000
$1,826,000
Electrical (15%)
$21,300
$40,500
$180,800
$222,900
$273,900
I/C (7 %)
$9,900
$18,900
$84,500
$104,000
$127,800
Site Work and Yard Piping (20%)
$28,400
$54,000
$241,000
$297,200
$365,200
Subtotal Costs
$201,600
$383,400
$1,711,300
$2,110,100
$2,592,900
Contractor Overhead and Profit (15%)
$30,200
$57,500
$256,700
$316,500
$388,900
Subtotal
$231,800
$440,900
$1,968,000
$2,426,600
$2,981,800
Contingency (20%)
$46,400
$88,200
$393,600
$485,300
$596,400
Subtotal
$278,200
$529,100
$2,361,600
$2,911,900
$3,578,200
Sales Tax (8%)
$19,500
$42,300
$188,900
$233,000
$286,300
Subtotal
$297,700
$571,400
$2,550.500
$3,144,900
$3,864,500
Engineering, legal and fiscal (25%)
$74,400
$142,900
$637,600
$786,200
$966,100
Total Opinion of Probable
$372,100
$714,300
$3,188,100
$3,931,100
$4,830,600
Construction Cost
Annual Operation and Maintenance
$87,000
$218,000
$91,000
$58,000
$58,000
Cost
Present Worth of Operations and
$854,000
$2,140,000
$893,000
$569,000
$569,000
Maintenance
Total Alternative Present Worth Cost
$1,338,100
$2,854,300
$4,081,100
$4,500,100
$5,399,600
The results of Table 6-13 illustrate a cost savings associated with retaining the existing
chlonnation 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
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annual interest rate of 8 percent. In developing the operation and maintenance costs, unit costs
consistent with values previously presented were used. Gaseous chlonne costs were estimated at
$0.20/1b, sulfur dioxide costs were estimated at $0.25/1b, hypochlonte costs were estimated at
$0.50/Ib, bisulfite costs were estimated at $0.65/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 the two open channel
ultraviolet light alternatives are similar, with the open channel low pressure system having a
slight advantage in capital cost, and the medium pressure alternative having a slightly lower
annual operation and maintenance cost.
6.11.3 Recommendations
Maintaining the existing dual channel gaseous chlorination system provides a cost effective
means for disinfection of the Yakima Regional Wastewater Treatment plant discharge. Because
this alternative involves the least change to existing infrastructure, it is also the easiest to
implement.
There is a significant non -economic price associated with the gaseous chlorine disinfection
alternative. Handling of the hazardous gases in close proximity to commercial areas, and the
interstate highway, poses a potential significant health and safety risk. The decision to retain the
existing disinfection facilities should weigh these issues prior to making a decision solely on
estimated alternative cost. After 2020, the existing chlorination/de-chlorination system will
require significant modification and expansion. City policy should ultimately determine whether
the existing systems are replaced with a safer technology such as ultraviolet disinfection.
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 are based on
application dosages averaging 1.40mg/1 for sodium hypochlorite to 1.00 mg/1 for chlorine gas.
Approximately 1.60 mg/1 of sodium bisulfite is needed to neutralize 1.00 mg/1 of chlorine. The
annual cost of hypochlorite use is anticipated to be three times greater than chlorine gas. The
annual cost of bisulfite use is anticipated to be two to three times greater than dioxide gas. Both
sodium hypochlorite and sodium bisulfite do present a safety risk for skin burns and/or eye
injuries from splashing or spilling.
Should the City determine that ultraviolet light will provide the best long-term strategy at the
wastewater treatment plant, it is recommended that a more detailed evaluation be performed
between the low pressure and medium pressure open channel alternatives. Low pressure systems
have a slight initial cost advantage. Medium pressure offers an operations and maintenance
advantage including a smaller footprint and less operations and maintenance due to fewer lamps.
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6.12 Waste Activated Sludge Thickening Alternatives
The waste activated sludge (WAS) thickening process reduces the volume of WAS sent to
downstream stabilization and dewatering processes. The Yakima Regional WWTP currently has
one dissolved air flotation thickener (DAF!') to thicken secondary sludge. A second thickening
unit of process is needed for redundancy.
6.12.1 Alternatives Considered
The projected year 2020 WAS loading is 9,706 lb/d and 21,938 lb/d for annual
maximum day conditions. The annual average solids loading equates to a WAS
232,800 gallons (0.5 percent solids) per day at year 2020 annual average conditions.
Three options were examined for providing waste activated sludge thickening
redundancy:
> Install a redundant dissolved air flotation thickener.
> Install a gravity belt thickening system for redundancy.
> Install a rotary drum thickening system for redundancy.
Install Redundant Dissolved Air Flotation Thickener
average and
flow rate of
process unit
In this approach, the existing thickening system would be backed by a redundant dissolved air
flotation (DAFT) thickener. Based on operation experience at Yakima, this approach would be
expected to produce similar solids concentrations of 3 to 4 percent when handling secondary
sludge. The new redundant DAFT unit would be designed to meet a minimum hydraulic loading
rate of 1.0 to 2.0 gpm/SF and a solids loading rate of 1.0 to 3.0 lb/hr/sf. The new unit would be
rectangular, located inside the existing Solids Handling Building made available by
improvements to the solids handing process. Based upon an organic loading rate of 9,706 lb/d
and loading rate of 2.0 lb/hr/sf, a minimum thickener float area of 210 square feet would be
needed.
Because the dissolved air flotation unit would be operated on a continuous basis, additional
storage of the WAS flows prior to thickening would not be required.
Install Gravity Belt System for Redundancy
Under this alternative, redundant secondary sludge thickening would be provided by installing a
gravity belt thickener. Because this unit would serve as a backup to the existing DAFT unit, it is
anticipated that the unit would operate on a continuous basis when running. Typical loading
rates for secondary sludge through gravity belt thickeners ranges from 100 to 200 gpm per meter
of belt width. For this analysis, 100 gpm has been used. Based upon a design flow of 232,800
gallons/day, a single 1.5 meter would be sufficient to handle the design condition allowing some
down time for required maintenance activities. Dewatenng performance is expected to be in the
4 to 6 percent solids range for this equipment.
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Because it is anticipated that the unit would operate on a continuous basis as a temporary backup,
construction of WAS storage upstream from the thickening process would not be required. The
1.5 meter gravity belt thickener and associated polymer pumps, sludge feed pumps, and
thickened sludge pumps would be installed in the Solids Handling Building in area coordinated
with improvements made to other solids handling processes.
Install Rotary Drum System for Redundancy
Similar to the gravity belt thickener alternative, this alternative would provide redundancy to the
WAS thickening system by installing a rotary drum thickener in the existing Solids Handling
Building. Rotary drum thickeners function similar to a gravity belt thickener in that free water
drains through a porous media while flocculated solids are retained on the media. The rotary
drum thickener consists of an internally -fed rotary drum with an integral internal screw for
transporting thickened solids out of the drum. These units can be automated to run continuously
with limited operator attention. Facility requirements for the rotary drum thickener are nearly
identical to gravity belt thickeners. Based upon available standard equipment sizing and the
design WAS rate of approximately 200 gpm, a single 300 gpm rotary drum thickener is
anticipated for this alternative. The dewatering performance with this equipment alternative is
expected to be 4-6 percent solids, slightly better than the dissolved air flotation unit.
Also like the gravity belt thickener option, it is anticipated that the unit would operate on a
continuous basis as a temporary backup. Construction of an intermediate WAS storage basin
would not be required and all support equipment and chemical feed pumping would be housed in
the existing Solids Handling Building.
6.12.2 Alternatives Evaluation
D A second DAFT unit will provide the needed process unit redundancy and ease of
maintenance and operation due to the operation staff's familiarity with the system.
D Gravity belt thickeners are simple to operate and reliable and can thicken to a slightly
better solid concentration than the DAF1 unit.
D Rotary drum thickeners have been historically easy to operate. Much like the gravity belt
thickeners, they also can thicken secondary sludge to a slightly higher solids
concentration than DAFT.
D The gravity belt thickener and rotary drum thickener alternatives would require
continuous operation of these units. Although these units can be configured for reliable
continuous operation, there are a significantly greater number of operating equipment
items associated with their operation requinng greater attention.
D All three thickening alternatives would be provided with air quality control facilities.
Because the DAFT unit can be fitted with a low profile cover and not require personnel
access, less air volumes would be developed for delivery to the air quality control system.
D The gravity belt thickener and rotary drum thickener alternatives can produce a slightly
higher thickened solids concentration than the DAFT unit (4 to 6 percent solids versus 3
to 4 percent solids)
The opinion of probable costs of the waste activated sludge thickening alternatives are presented
in Table 6-14. The estimates in Table 6-14 are based upon installation of a redundant WAS
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thickening system to serve as backup to the existing dissolved air flotation unit on a short-term
basis. The estimates are based upon providing the capacity needed for year 2020 average daily
conditions. All three alternatives also provide sufficient redundant capacity to ultimate build -out.
Table 6-14 also shows estimated annual operation and maintenance costs associated with each
alternative. The 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 8 percent. In
developing the operation and maintenance costs, unit costs are consistent with values previously
presented. The polymer unit costs were based on $2.15/1b and miscellaneous costs were
calculated at 3 percent of annual operation and maintenance costs. Because all three alternatives
would be used as temporary backup to the existing thickening system, it is anticipated that the
alternatives presented would only be operated for 25 percent of the year.
Table 6-14. Opinion of Probable Cost for WAS Thickening Alternatives
Unit
Opinion of Probable Cost (to Build -out)
DAFT1
Gravity Belt
Thickener2
Rotary Drum
Systema
Facility Construction and Retrofits
$506,000
$649,000
$898,000
Electrical (15%)
$75,900
$97,400
$134,700
I/C (7 %)
$35,400
$45,400
$62,900
Site Work and Yard Piping (20%)
$101,200
$129,800
$179,600
Subtotal Costs
$718,500
$921,600
$1,275,200
Contractor Overhead and Profit (15%)
$107,800
$138,200
$191,300
Subtotal
$826,300
$1,059,800
$1,466,500
Contingency (20%)
$165,300
$212,000
$293,300
Subtotal
$991,600
$1,271,800
$1,759,800
Sales Tax (8%)
$79,300
$101,700
$140,800
Subtotal
$1,070,900
$1,373,500
$1,900,600
Engineering, legal and fiscal (25%)
$267,700
$343,400
$475,200
Total Opinion of Probable Cost
$1,338,600
$1,716,900
$2,375,800
Annual Operation and Maintenance Cost
$14,000
$23,000
$23,000
Present Worth of Operation and
$137,000
$226,000
$226,000
Maintenance
Total Alternative Present Worth Costs
$1,475,600
$1,942,900
$2,601,800
'Cost for a 8 foot by 26 foot unit with an 8 foot side wall depth.
2Single 1.5 meter gravity belt system.
3Single 300 gpm rotary drum system.
6.12.3 Recommendations
The results of Table 6-14 illustrate the capital and operation and maintenance costs are less for
the dissolved air flotation thickener alternative and provides the most cost-effective long-term
solution for WAS thickening redundancy. Since the Yakima wastewater treatment plant has an
existing dissolved air flotation thickener and the plant staff is familiar with, and satisfied with, its
operation and performance, a second dissolved air flotation thickener is recommended.
6.13 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
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gases and vapors. The following discussion reviews the available options for control of air
emissions.
• 6.13.1 Atmospheric Dispersion
•
•
Gasses 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.
6.13.2 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. 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
coumann, 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.
6.13.3 Liquid Phase Treatment
Air emission reduction can be accomplished by chemically or biologically altenng 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.
6.13.3.1 Chemical Addition
Chemicals may be added within the treatment plant to oxidize or precipitate air emission
compounds. Commonly used chemicals include hydrogen peroxide, potassium permanganate,
iron salts, and chlonne.
Chlorine is a chemical oxidant with the reactive component being the hypochlonte 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.
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Since chlonne is considered to be a potentially hazardous matenal 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 matenals, the maintenance and operation of hydrogen
peroxide systems require special training, maintenance, operational procedures, and safety
practices. Hydrogen peroxide is not recommended for long term air emission abatement within a
wastewater treatment facility.
Potassium permanganate is another strong oxidant which usually requires 6 or more parts for
each part of sulfide. Because potassium permanganate is expensive, and can be explosive when
it comes into contact with acids or organics, its use as a air emission control chemical in
wastewater treatment facilities which process organics is not recommended.
Iron salts are sometimes used to control H2S. Ferrous and ferric salts form a very insoluble
precipitate FeS with H2S. The resultant precipitate typically will turn the sewage black and the
flocculant increases the rate that other solids in the process settle. Iron salts are very reactive
with any ferrous metal and must be handled with great care as one drop will penetrate a steel toed
work boot in minutes. Protective clothing and safety of operational and maintenance personnel is
an issue when iron salts are used. Iron salts are not recommended for air emission abatement in
large scale wastewater treatment plants.
While anthraquinone caustic slug dosing, and nitrate addition, are used for air emission control in
collection systems, their application in a wastewater treatment facility is limited. The effects of
these chemicals is short lived and can be detrimental to the biological process in an activated
sludge treatment facility. These chemicals are not recommended.
6.13.4 Gas Phase Treatment
Gas 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.
6.13.4.1 Ozone
Ozone is a powerful oxidant that is most often applied to high strength, low volume air. It is often
used in industrial applications. Ozone is a very unstable gas and requires on-site generation. An
air -fed ozone system consists of an air pretreatment system (compressors, heat exchanger, air filters,
molecular sieve), an ozone generator (passes the pretreated air through a discharge gap across
which a high voltage is applied), a diffuser or injector, and a baffled contact chamber. Ozone feed
to the reactor may be automatically controlled by maintaining a minimum ozone residual in the
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reactor exhaust. A dosage rate of 1 to 2 ppm may be sufficient for most air emission, however it
may be inadequate for peak conditions, such as from dewatering operations, which may require 10
ppm. A contact time of 30 to 40 seconds is recommended. Personnel must be well-trained in the
proper safety procedures with the ozone system. Safety regulations set a limit of 8 hours
continuous exposure of individuals to a concentration of 0.1 ppm ozone. Ozone monitors and
alarms are necessary in the discharge stack of the reactor. Ozonation is very expensive for the
volume of air emissions typically generated at a wastewater treatment plant; consequently, it is
seldom used in this application.
6.13.4.2 Impregnated or Nonimpregnated Activated Carbon
Impregnated and nonimpregnated activated carbon (collectively referred to as "AC") can remove
compounds from an air stream through a process known as adsorption. An adsorbent has a natural
affinity for a particular substance. AC particles have a large surface area relative to their weight,
providing "sites" for the entrapment of air molecules. Because AC is non -polar, water molecules,
which are highly polar, are not attracted to the sites, benefiting the use of AC in treating wastewater
air streams which are often high in humidity. Nonimpregnated AC is effective over a wide range of
organic and inorganic types and concentrations, and can be regenerated thermally (a regeneration
facility is located in western Washington), or landfilled. The adsorptive capacity of
nonimpregnated AC for H2S is 0.1 pound per pound of AC.
AC impregnated with a chemical such as sodium hydroxide or potassium hydroxide raises its pH
and increases its adsorptive capacity for acidic gasses such as H2S (0.2 pounds per pound of
impregnated AC). Impregnated AC used for treating sewage gasses is usually landfilled, although
chemical regeneration to restore some of the adsorptive capacity is sometimes practiced.
The chief advantage of AC systems is the simplicity of these systems relative to other control
technologies. A chief disadvantage is that the cost of replacing spent AC usually limits the use of
these systems to treating small volume (roughly defined as lower than 5,000 cfm) and low air
emission concentration (roughly defined as less than 10 ppm H2S concentration) sources.
An AC system is not recommended for treating the air emissions from the major sources at
wastewater treatment plants for the following reasons:
➢ AC systems are subject to fouling by moist air flows containing relatively light
concentrations of oils and other particulates. Air streams from turbulent raw wastewater
processes, such as the headworks, should be pretreated by filtering or other means to
remove these substances prior to treatment in an AC unit. It is possible to "blind" the
surface of the carbon bed causing a much shorter run time of the filter than expected.
➢ AC systems are subject to shortened run cycles from the adsorption of hydrocarbons, which
could be present in the plant influent in small quantities under normal conditions, but could
quickly deplete the capacity of the AC system in the event of a fuel spill in the collection
system.
➢ Not cost effective for high volume systems.
➢ The economics of an AC system are heavily dependent upon the cost of carbon, which has
shown wide fluctuations in the past.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 47
DRAFT
AC should be considered only for treating isolated air sources that cannot be cost-effectively treated
in a central air emission treatment system serving the treatment plant.
• 6.13.4.3 Atomized Mist Liquid Scrubbing
•
•
Atomized mist scrubbers are similar to packed tower liquid scrubbers, as are used at the Yakima
facility, in that they use a liquid scrubbing solution to capture and oxidize air emissions. The
scrubbing liquid is maintained at a high pH through the addition of sodium hydroxide, promoting
absorption of gasses into solution. The scrubbing solution also contains an oxidant to destroy the air
emission substances. Atomized mist scrubbers typically use chlorine solution as the oxidant.
An atomized mist scrubber consists of vertical or horizontal, cylindncal chamber, usually made of
fiberglass, into which is introduced an atomized spray of scrubbing liquid. Specially designed
nozzles at the top of the chamber create the mist by injecting scrubbing chemical into a stream of
compressed air that is released from the nozzle to produce droplets in the 10-20 micron size. The
air to be treated passes through the chamber, and the mist containing the oxidized compounds
eventually settles to the floor of the scrubbing chamber and is drained to waste. Feed rates of
chemicals are controlled by pH and oxidation-reduction potential (ORP) probes in the waste
solution exiting the scrubber.
While mist scrubbers are widely used, and often provide excellent performance, they have several
drawbacks that must be considered:
➢ The exhaust air leaving the discharge nozzle can result in high noise levels. Atomized mist
scrubbers are sometimes located inside buildings to contain this noise.
➢ Mist scrubbers have limited ability to detect, and quickly respond to peaks or "spikes" in the
air to be treated. This is due to the method of using the spent scrubbing liquid to gauge the
necessary adjustments to the chemical dosage required. These adjustments may not be
made until the spike, or the front-end of the spike, has passed through the scrubber, possibly
receiving only partial treatment.
➢ Mists of scrubbing compound are sometimes released in the tower exhaust. A distinctive
chlorine smell can sometimes be detected downwind of atomized mist scrubbers.
➢ For a comparable air volume, mist towers are considerably larger than packed towers.
As discussed in the next section, packed towers overcome several of these drawbacks.
6.13.4.4 Packed Tower Liquid Scrubbing
Packed tower liquid scrubbers are similar to the atomized mist scrubbers described earlier in that
they absorb compounds into the liquid phase where they can be quickly oxidized by sodium
hypochlonte, chlonne, 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 gasses, 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,
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000 Page 48
DRAFT
high ORP) 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. The quantity of the wasted chemical solution is usually small (10-
20 gpm) and would be quickly diluted and not have an effect on the biological processes in the
plant.
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.
Single stage treatment is usually adequate for treating normal sewage gas.
Packed tower liquid scrubbing is commonly used for air sources at wastewater treatment
facilities. Yakima's treatment system, illustrated in Figure 6-10, 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 air volume for proper operation of the trickling filters
exceeds 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.
Figure 6-10 — Yakima's Air Emission Treatment System
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 49
•
•
DRAFT
6.13.4.5 Compost Filter Treatment
Compost filter air treatment is gaining acceptance as a cost effective, efficient method of treating
wastewater point source air emissions. Numerous compost filter treatment systems have been
constructed and successfully operated in the United States in recent years.
The chief advantages of this technology are low operating costs and simplicity of operation. Air
compounds are removed by biological activity in a compost filter as the air passes through the
compost filter. The compost filter design must include an air distribution system that evenly
distributes the air beneath the filter media, an effective drainage system to remove excess water
from precipitation from the bed area, and a system for maintaining the proper moisture content of
the compost filter to support biological activity during dry periods. The compost media must be
carefully selected to support the biological activity, control pH, and provide good air flow
characteristics for years of extended service. Eventually the media must be replaced due to the
decomposition of the compost. It becomes more difficult to maintain the correct pH with the
continued removal of the acidic gasses such as H2S, and headloss becomes too great in the
compost filter due to settling and decomposition.
The chief disadvantages of a compost filter treatment system are the large land area required, and
the use of a biological process (which may be less reactive to loading changes than a chemical
oxidation process).
The compost material requires replacement after a number of years of use, typical replacement
estimates are a minimum of 5 years. Replacement of the bed is necessary when sufficiently high
pH levels cannot be maintained, when the organic matter in the bed is spent and does not support
biological growth necessary for efficient removal, or when the bed becomes compacted and results
in excessive pressure losses and/or reduced air flow. The spent media could be spread on
landscaped areas.
Briefly stated, the compost filter must not become too acidic, too wet, too dry, or too inert. There
is a fairly wide range of conditions in which the necessary biological activity will take place.
Proper design of the drainage, moisture control, and pH adjustment systems is necessary. Proper
selection and proportioning of the materials used for the filter media is also very important.
At the Yakima Regional WWTP, all collected air sources are routed to the Trickling Filters.
Treatment of the air within the trickling filter occurs in a similar fashion to a compost bed, as
there is continuous biological activity in the rock media. After the trickling filters the air is
passed through the packed tower scrubbers.
6.13.5 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 6-15 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.
HDR ENGINEERING, INC
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 50
Table 6-15. Air Emission Potential from Unit Processe
DRAFT
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.
Minor air emission potential as some turbulences maybe
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 Pumping
Station
This area has a slight 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.
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.
Not enclosed
Secondary Clarifiers
Minimal air emission potential as the water at this point
in the process is rich in oxygen.
Not enclosed
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.
Storage Lagoons
Air emission potential is from storage of solids and
discharge of centrifuge supernate.
Not enclosed
HDR ENGINEERING, INC
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 51
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6.13.6 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. Section 9
discusses the Biosolids Alternatives in detail and the remediation for the potential air emissions
from the biosolids storage areas.
6.13.6.1 Parshall Flume and Primary Clarifier Influent Channel
These channels have a minor potential to release air emissions since there is only a slight
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 the
Trickling Filters and existing packed tower scrubber facilities.
6.13.6.2 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 6-11 illustrates typical weir and launder covers for circular clarifiers.
Figure 6-11 — Typical Weir and Launder Covers
Another potential source of air emission at the primary clarifiers is the center influent well where
the wastewater is introduced into the clarifier. This area has minor turbulences and is considered
a potential source of air emissions.
Covering the entire primary clarifier surface would result in the capture of all air emissions from
this system. As with the influent channel, ventilation air from this area could be routed to the
Trickling Filters and the existing packed tower scrubber facilities. This option would result in
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 52
DRAFT
potential operational problems. Operations and maintenance personnel would be hampered in
the operation, maintenance, and cleaning of this critical unit process in the facility.
6.13.6.3 Return Activated 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.
Enclosing this area would reduce the air emissions from the RAS pumping station. As with the
other unit processes, ventilation air would be ducted to the Trickling Filters for initial treatment
and then to the packed tower scrubber facilities for final treatment.
6.13.6.4 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. The only potential area for air emissions is at the centerwell
where RAS is drawn off the underflow of the clarifier. Covering this area would result in the
capture of all potential air emissions. If the centerwell is covered, the operators may have
difficulty regulating the secondary treatment process. The operators would be unable to view the
quantity and quality of the RAS. Maintaining RAS flow is critical to the activated sludge
biological process.
6.13.6.5 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 unpleasant air emissions.
6.13.6.6 Storage Lagoons
The storage lagoons represent a potential source of air emissions resulting from the storage of
digested solids, and from the discharge of centrifuge centrate from the dewatering process. The
City has discontinued the use of the storage lagoons for storage of digested solids. Centrifuge
centrate, which is high in ammonia concentration, continues to be discharged to the storage
lagoons.
Air emissions from the storage lagoons may occur as the result of exposure of the digested solids
to air, or as the result of ammonia volatilization from evaporation and/or wind action. Covenng
of these large storage lagoons would result in capture of all potential air emissions from this
source. If the storage lagoons were to be covered, the ventilated air would be routed to the
Trickling Filters and the existing packed tower scrubber facilities.
Placing covers over the large storage lagoons would cause significant operations and
maintenance problems associated with maintaining an aerated water layer above the stored
solids, and with the removal of stored solids during scheduled cleaning periods. The continue
use of the storage lagoons for centrifuge Centrate is discussed in Section 9.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 53
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6.13.7 Opinion of Probable Costs
Table 6-16 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.
acne i -z, ()pinion or Prooaoie c;ost or control improvements
DESCRIPTION
PARSHALL
FLUME
AND
PRIMARY
CLARIFIER
INFLUENT
CHANNEL
PRIMARY
CLARIFIER
WEIRS AND
CENTERWELL
PRIMARY
CLARIFIER
COVERS
RAS
PUMPING
STATION
COVERS
SECONDARY
CLARIFIER
COVERS
STORAGE
LAGOON
COVERS
Facility Costs
$150,000
$340,000
$1,200,000
$90,000
$2,140,000
$3,630,000
Site Work @20%
$30,000
$68,000
$240,000
$18,000
$428,000
$726,000
Contractor OH & Profit @15%
$27,000
$61,200
$216,000
$16,200
$385,200
$653,400
Contingency @ 20%
$41,400
$93,800
$331,200
$24,800
$590,600
$1,001,900
Sales Tax @ 8%
$19,900
$45,000
$159,000
$11,900
$283,500
$400,800
lirr/Legal/Admin @ 25%
$67,100
$152,000
$536,600
$40,200
$956,800
$1,352,600
al Opinion of Probable
$335,400
$760,000
$2,682,800
$201,100
$4,784,100
$6,762,800
Chemicals and Power
$1,000
$1,000
$4,000
$1,000
$2,000
$3,000
Personnel
$10,000
$10,000
$25,000
$10,000
$25,000
$40,000
Present Worth of O&M Costs
$137,100
$137,100
$361,400
$137,100
$336,500
$535,900
Total Present Worth
$472,500
$897,100
$3,044,200
$338,200
$5,120,600
$7,298,700
•
6.13.8 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, the areas modified that had a potential for air emissions have been covered
and ventilated to capture and treat the air. Each unit process has a potential to release air
emissions. The level of air emissions present at the process unit may be too low to be detectable
outside of the confines of the wastewater treatment facility. If unit processes or specific areas
within the facility are expected to produce air emissions, then these areas should be evaluated in
greater detail to determine the most cost-effective method to reduce their air emission potential.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 54
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6.14 Wastewater Treatment Resource Requirements
To satisfy 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, it is imperative that adequate
operations and maintenance be performed at the Yakima Regional WWTP.
In general, the annual costs of operations and maintenance of the Yakima Regional WWTP can
be separated into seven primary categones: 1) Staffing; 2) Utilities; 3) Chemicals; 4) Equipment;
5) Materials; 6) Contract Services; and 7) Other. Capital expenditures -are considered separately
from operations and maintenance requirements. Approximately 50 percent of all annual
operation and maintenance expenditures at the Yakima Regional WWTP are associated with
staffing of the various functional areas of the treatment facilities. In addition to operations and
maintenance of the treatment facilities, staffing includes resources for the Pretreatment Program,
and for the Laboratory services.
6.14.1 Treatment Plant Resource Requirements
Operations staffing at the Yakima Regional WWTP provides for the continuous day to day
functions of primary treatment, secondary treatment, and solids handling. The Operations staff
are responsible to ensure compliance with the NPDES permit requirements. As the facility has
increased in size and complexity, the requirements for the Operations staffing have increased.
Each functional area of the treatment plant must be monitored for performance, efficiency,
calibration, sampling, and reporting. Routine operations include cleaning, protective coatings,
and maintenance of a safe and presentable working environment. Three elements of operation
which have required increased staffing are public relations, contingency planning, and safety
training and compliance.
Maintenance staff are responsible for preventative and predictive maintenance of mechanical and
electncal equipment for reliability of critical system components, as well as responding to
unplanned equipment breakdowns. Each mechanical and electrical component in the treatment
plant must be visited on a scheduled basis for routine and major maintenance. The predictive
maintenance program utilizes periodic measurements to evaluate operational status, indicate
potential problems, and mitigate equipment breakdown before it occurs.
The proposed modifications and improvements set forth in the this section do not add new
process treatment systems at the Yakima Regional WWTP. The existing treatment process
systems will be increased in size to accommodate wastewater flows as population increases
throughout the service area.
As new equipment and enlarged treatment process systems are added, additional Maintenance
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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 55
DRAFT
The increase in size of the existing treatment process systems should not require the addition of
new Operations staff in the immediate future. If a new Septage Handling Facility is constructed
at the Yakima Regional WWTP, it is likely that one new Operator's position will be needed.
Other possible increases in Operations staff may be required if the facility should implement
enhanced forms of treatment such as: 1) Class A Digested Solids — 1 Operator; and 2) Biological
Nutrient Removal — 2 Operators.
6.14.2 Pretreatment Program Resource Requirements
A fully delegated Pretreatment Program will require additional resources for the City of Yakima
wastewater utility for 1) Permit administration, and 2) Business inspections.
At the current time, the WDOE is writing State Waste Discharge (SWD) permits for individual
commercial and industrial customers discharging to the Yakima Regional WWTP facilities.
With a fully delegated pretreatment program, the City of Yakima will be responsible for wnting
permits for those individual commercial and industrial customers now receiving a SWD permit.
In issuing a SWD permit, the WDOE uses a permit fee schedule as set forth in WAC 173-224.
Staffing requirements for administering the SWD permits for a fully delegated Pretreatment
Program are estimated based on a staffing model developed by WDOE. For the purposes of this
section, all dollar figures shown for permitting, and all staffing projections are based on the
WDOE standard schedules.
Since 1988, the average SWD permit has increased from a one page document outlining
discharge limits, to a 25 page document covering discharge limits, monitoring schedules, spill
prevention plans, training requirements, sampling and analysis requirements, reporting
requirements, operations and maintenance, and record keeping requirements. These
requirements are mandated by WAC 173-216 and no reduction of these requirements is
anticipated in the future.
There are three levels of commercial and industrial customers that require SWD permits. Federal
pretreatment categories are set out in 40 CFR 403, Appendix C. These are commercial and
industnal customers that have been designated by EPA to have the potential to significantly
effect water quality. 40 CFR 403 also requires commercial and industrial customers that
discharge over 25,000 gallons per day to be permitted. State categories are set forth in WAC
173-224. These categories cover several types of businesses, such as fruit packers, boat yards,
and wineries that are not found in the Federal regulations. In addition, the City of Yakima has
the right to permit any commercial or industrial customer that may significantly affect the
Yakima Regional WWTP.
Federal categorical commercial and industrial customers, and all customers discharging over
25,000 gallons per day, are automatically classified as Significant Industrial Users (SIU's). All
SIU's must be permitted. State categorical commercial and industrial customers may be
considered Minor Industrial Users (MIU's), but they also must be permitted. Remaining
businesses that discharge process wastewater to the Yakima Regional WWTP may be permitted
at the City's discretion. There are some businesses that the City may permit that are not in a
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CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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DRAFT
Federal or State Category (microbreweries), but there is no intent or need to permit every
business in Yakima.
Table 6-17 identifies those commercial and industrial customers that are currently permitted
under the SWD permit programs by WDOE. A total of 35 permits are currently in place,
resulting in $218,407 in revenue to WDOE, and requiring the equivalent of 1.18 full-time
employees for management, reporting, and inspections of the 35 permits.
Table 6-17. City of Yakima 1998 Permits'
Permit Type
Cost
Number
Total Dollars
Total FTE2
Source
Crop Preparing
g. 25,000 - < 50,000 bins/yr
$5,858
3
$17,574
0.096
h. 50,000 - < 75,000 bins/yr
$6,510
15
$97,650
0 48
Fruit Packers
i. 75,000 - < 100.000 bins/yr
$7,574
1
$7,574
0.032
j. 100,000 - < 125,000 bins/yr.
$9,469
3
$28,407
0.096
Facilities Not Otherwise Classified
b. 1,000 - < 10,000 gpd
$2,367
2
$4,734
0 072
Tennaco, Dowty Aerospace
c. 10,000 - < 50,000 gpd
$5,918
2
$11,836
0.108
Yakima Brewing, Pepsi Cola
Flavor Extraction
$121
3
$363
0 096
J.I. Haus, Hops Extract
Food Processing
•
g. 500,000 - < 750,000 gpd
$19,529
1
$19,529
0 036
Del Monte
Hazardous Waste Clean Up Sites
a. Leaking Underground Storage Tanks
(LUST)
I 1 State Permit
$3,105
3
$9,315
0.096
Average
Ink Formation and Pnnting
a. Commercial Print Shops
$1.821
0
-
b Newspapers
$3.035
0
-
c. Box Plants
$4,856
1
$4,856
0.032
Longview Fibre
Timber Products
a. Log Storage
$2,367
0
-
b Veneer
$4,734
0
-
c. Sawmils
$9,469
0
-
d. Hardwood, Plywood
$16,569
1
$16,569
0 036
Boise Cascade
Total
35
$218,407
1.18
•
1 Costs are fees set by WAC 173-224 These estimates are for Yakima only
2. FTE Estimates are for permit writing/administration only Additional staffing would be required for field operations.
The WDOE has been selective in wnting and issuing permits within the City of Yakima. With a
fully delegated pretreatment program, the City will be required to issue permits to all potential
facilities identified in federal and state categories, and not just the selective few chosen by the
WDOE. Table 6-18 provides a listing of all those permits which the City of Yakima believes
should be in place at the current time. The table does not include permits in the Terrace Heights
or Union Gap service areas. As shown, a total of 74 permits should currently be in place,
resulting in $313,197 in revenue, and requiring a total of 2.48 full-time equivalent employee's for
management, reporting, and inspections.
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CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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DRAFT
!awe o-18. tstumarea uiry or ratama rsecommenaea Perm►rs-
Permit Type
Cost
Number
Total Dollars
Total FTE2
Source
0 Commercial Laundry
Crop Preparing
g. 25,000 - < 50,000 bins/yr
h. 50,000 - < 75,000 bins/yr
i. 75,000 - < 100,000 bins/yr
j 100,000 - < 125,000 bins/yr
Facilities Not Otherwise Classified
$303
$5,858
$6,510
$7,574
$9,469
2
3
15
1
3
$606
$17,574
$97,650
$7,574
$28,407
0.064
0.096
0 48
0 032
0.096
Crystal Linen, Yakima Medical
Laundry
Fruit Packers
b 1,000 - < 10,000 gpd
$2,367
3
$7,101
0 108
Tennaco, Fairgrounds, Dowty
Aerospace
c. 10,000 - < 50,000 gpd
$5,918
2
$11,836
0.108
Yakima Brewing, Pepsi Cola
d. 50,000 - < 100,000 gpd
$9,469
2
$18,938
0.108
Memorial, Providence Hospital
Flavor Extraction
a. Steam Distillation
$121
3
$363
0.096
J.I. Haus, Hops Extract
Food Processing
g. 500,000 - < 750,000 gpd
$19,529
1
$19,529
0.036
Del Monte
Hazardous Waste Clean Up Sites
a. Leaking Underground Storage Tanks
(LUST)
1 State Permit
$3,105
3
$9,315
0.096
Average
Ink Formation and Printing
a. Commercial Print Shops
$1,821
10
$18,210
0.32
Estimate
• b. Newspapers
$3,035
1
$3,035
0 032
Yakima Herald
c. Box Plants
$4,856
1
$4,856
0.032
Longview Fibre
Noncontact Cooling Water With Additives
a. < 1,000 gpd
$740
-
b 1,000 - < 10,000 gpd
$1,479
8
$11,832
0.256
c. 10,000 - < 50,000 gpd
$2,220
3
$6,660
0.096
Estimate
Noncontact Cooling Water Without Additives
a. < 1,000 gpd
$592
-
b 1,000 - < 10,000 gpd
$1,184
-
c. 10,000 - < 50,000 gpd
$1,776
3
$5,328
0.096
Estimate
d. 50,000 - < 100,000 gpd
$4,143
1
$4,143
0.032
Photofinishers
a. < 1,000 gpd
$947
5
$4,735
0 16
Estimate
b. 1,000 gpd or greater
$2,367
1
$2,367
0.032
Photo Haus
Pulp, Paper and Paper Board
a. Fiber Recyclers
$11,835
1
$11,835
0 036
Michaelson Packaging
Timber Products
a. Log Storage
$2,367
-
b. Veneer
$4,734
-
c. Sawmils
$9,469
-
d. Hardwood, Plywood
$16,569
1
$16,569
0 036
Boise Cascade
•
HDR ENGINEERING, INC
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 58
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Table 6-18. Estimated City of Yakima Recommended Permits1 (Cont
Type
Cost
Number
Total Dollars
Total FTE2
Source
•Permit
Vehicle Maintenance
a. < 0.5 acre
$2,367
b 0.5 - < 1 0 acre
$4,734
1
$4,734
0 032
City Shop
c. 1 0 acre and greater
$7,102
Total
74
$313,197
2.48
1 Costs are fees set by WAC 173-224 These estimates are for Yakima only
2. FTE Estimates are for permit writing/administration only Additional staffing would be required for field operations.
Selective permitting of commercial and industrial customers by the City of Yakima would
expose the City to citizen lawsuits and regulatory action from the WDOE and/or EPA.
Both the EPA and WDOE continue to update water quality objectives, and many of the City's
current Minor Industrial Users may become Significant Industrial Users in the future. Recent
legislation will add autobody shops, machine shops, metal fabrication facilities, gas stations,
industrial cleaners, doctor offices, dentist offices, and other such facilities to the SIU category
before the City of Yakima accepts responsibility for the fully delegated pretreatment program in
2002.
The Metal products and Machinery pretreatment category is expected to be published in the
Federal Register in early 2000 with final adoption by December 2002. This category will impact
a significant number of commercial and industrial facilities in the Yakima Metropolitan Area. In
addition to "existing and new facilities that manufacture, maintain, or rebuild finished metal
parts, products, or machines", this category will include commercial and industrial facilities not
exclusively devoted to metal products and machinery such as:
Business
K -Mart, Wal-Mart
J.M. Perry
Medic I
Dunbar Jewelers
Cliff Miller's
Photo Haus
G.T.O. Carwash
Primary Business
General Merchandise
Educational Services
Misc. Medical
Misc. Retail
Misc. Retail
Misc. Retail
Misc. Retail
Affected Division
Automotive Shops
Automotive Shop
Passenger Transportation
Precious Metals
Computer Related Services
Photographic Equipment
Carwash
Some of the businesses affected by this regulation are currently Minor Industrial Users (MIU's)
or Insignificant Industrial Users (IU's). All, within the affected umbrella of this new rule, must
tentatively be classified as SIU's. Many of the aforementioned businesses will likely remain
SIU's with mandatory permitting, inspection, and monitoring requirements. Some of the
aforementioned businesses may be downgraded to MIU's, but all are required to be inspected at
least once to ascertain the product or service being offered.
Those businesses classified as SIU's must be sampled twice a year. Even with an estimate of
• only 100 new SIU's, the wastewater laboratory does not have the capacity to perform 200
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 59
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additional metals tests per year. The pretreatment program must either send out hundreds of
samples, or upgrade the laboratory.
The Metal Products and Machinery regulations are expected to raise a number of jurisdictional
issues. The City Public Works complex will become a Significant Industnal User (SIU's) and be
subject to periodic inspection and sampling. Other public agencies such as the County Public
Works, Department of Transportation, Washington State Patrol, the Airport, U.S. Post Office,
School Districts, and any other agency that have motor vehicles may be affected by this
regulation if connected to a public sewer and maintenance is performed on site.
According to EPA, this regulation is not considered to be an unfunded mandates legislation
because this regulation was already under development when the unfunded mandates legislation
was passed.
Table 6-19 identifies the expected number of commercial and industrial facilities that the City of
Yakima anticipates will require permits in 2002. The City pretreatment staff is currently
updating the Industrial Waste Survey (IWS) required under the new NPDES permit. The results
of the IWS will identify all the commercial and industrial facilities which will likely be permitted
when the fully delegated pretreatment program is implemented by the City of Yakima.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 60
DRAFT
!able 6-79. tstimatea Uity or Yakima Permits in ZUU7 "
Permit Type
Cost
Number
Total Dollars
Total FTE2
Source
0 Commercial Laundry
Crop Preparing
g. 25,000 - < 50,000 bins/yr
h. 50,000 - < 75,000 bins/yr
i. 75,000 - < 100.000 bins/yr
j. 100,000 - < 125,000 bins/yr
Facilities Not Otherwise Classified
a. < 1,000 gpd
b 1,000 - < 10,000 gpd
c. 10,000 - < 50,000 gpd
d. 50,000 - < 100,000 gpd
$303
$5,858
$6,510
$7,574
$9,469
$1,184
$2,367
$5,918
$9,469
2
3
15
1
3
0
3
2
2
$606
$17,574
$97,650
$7,574
$28.407
-
$7,101
$11,836
$18,938
0.064
0.096
0 48
0.032
0 096
-
0.108
0 108
0 108
Crystal Linen
Fruit Packers
Tennaco, Fairgrounds, Dowty
Aerospace
Yakima Brewing, Pepsi Cola
Memorial, Providence Hospital
Flavor Extraction
a. Steam Distillation
$121
3
$363
0.096
J.I. Haus, Hops Extract
Food Processing
g. 500,000 - < 750,000 gpd
$19,529
1
$19,529
0.036
Del Monte
Hazardous Waste Clean Up Sites
a. Leaking Underground Storage Tanks
(LUST)
1. State Permit
$3,105
3
$9,315
0.096
Estimate
Ink Formation and Printing
a. Commercial Print Shops
$1,821
10
$18,210
0.32
Estimate
• b Newspapers
c. Box Plants
$3.035
$4,856
1
1
$3,035
$4,856
0 032
0 032
Yakima Herald
Longview Fibre
Metal Fabricators3
$1,419
50
$70,950
1 6
Estimate
Noncontact Cooling Water With Additives
a. < 1,000 gpd
$740
0
-
-
b 1,000 - < 10,000 gpd
$1,479
8
$11,832
0.256
Estimate
c. 10,000 - < 50,000 gpd
$2,220
3
$6,660
0 096
Noncontact Cooling Water Without Additives
a. < 1,000 gpd
$592
0
-
-
b 1,000 - < 10,000 gpd
$1,184
0
-
-
c. 10,000 - < 50,000 gpd
$1,776
3
$5,328
0.096
Estimate
d. 50,000 - < 100,000 gpd
$4,143
1
$4,143
0 032
Photofinishers
a. < 1,000 gpd
$947
5
$4,735
0 16
Estimate
b 1,000 gpd or greater
$2,367
1
$2,367
0 032
Photo Haus
Pulp, Paper and Paper Board
a. Fiber Recyclers
$11,835
1
$11,835
0.036
Michaelson Packaging
Timber Products
a. Log Storage
$2,367
0
-
-
b Veneer
$4,734
0
-
-
c. Sawmils
$9,469
0
-
-
d. Hardwood, Plywood
$16,569
1
$16,569
0 036
Boise Cascade
•
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 61
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Table 6-19. Estimated City of Yakima Permits in 20011 (Cont)
Permit Type
Vehicle Maintenance
a. < 0.5 acre
b 0.5 - < 1 0 acre
Cost
Number
Total Dollars
Total FTE2
Source
c. 1 0 acre and greater
$2,367
$4,734
$7,102
0
0
$4,734
0 032
City Shop
Total
124
$384,147
4.08
•
•
1 Costs are fees set by WAC 173-224 These estimates are for Yakima only If City staff assist Union Gap and Terrace
Heights, there are an estimated 40 to 80 businesses that may need a discharge permit.
2. FTE Estimates are for permit writing/administration only Additional staffing would be required for field operations.
3 This estimate is based on EPA's definition of pretreatment categories.
Using the WDOE models for permitting fees and staffing, the fully delegated pretreatment
program will require approximately 124 permits, resulting in $384,147 in revenue, and requiring
the equivalent of 4.08 full-time employees for management reporting, and inspections.
In addition to the management, reporting, and inspection responsibilities of the permitting
process, the City will be required to conduct field sampling and laboratory testing of all
commercial and industrial facilities. Significant Industrial Users wastewater discharge must be
analyzed for pollutants at least twice per year. Each sampling event must be conducted over a 24
hour period. With over 124 permits, the sampling and testing will add over 248 sampling and
testing events to the City's current sampling and testing program for strong waste.
The strong waste/pretreatment program currently has two pretreatment technicians on staff,
collecting samples from commercial and industrial facilities, a minimum of 5 samples each per
month from Terrace Heights and Union Gap, and performing other duties assigned to the
program. Several of the commercial and industrial facilities currently monitored for strong waste
would also be monitored under the fully delegated pretreatment program. The strong waste
program has been proven effective in locating sources of strong waste and generating revenue
from these sources. As the result of the strong waste program, organic loading at the Yakima
Regional WWTP has been reduced, thereby preserving future capacity.
The fully delegated Pretreatment Program will add 2 additional pretreatment technicians,
including vehicle and equipment, for the increase in inspection and sampling of commercial and
industrial facilities. Although the commercial and industnal facilities may conduct their own
sampling and testing of the wastewater discharge, the City will be required to independently
verify compliance as mandated by 40 CFR 403.8 (f).
The fully delegated Pretreatment Program, together with the strong waste program, would
include 1 supervisor; 3 to 6 permit administrators responsible for writing permits, conducting on-
site inspections, monitoring reporting requirements, reviewing commercial and industrial
pretreatment plans, and working with commercial and industrial customers in meeting the
pretreatment regulations; 4 to 6 pretreatment technicians for sampling of wastewater discharge to
the collection system, conducting on-site assessments, sampling of Terrace Heights and Union
Gap wastewater, and performing other duties and responsibilities assigned by the supervisor; and
1 administrative assistant for record keeping and other duties. Table 6-20 identifies the expected
program cost for the Pretreatment Program and strong waste program.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 62
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Table 6-20. City of Yakima Pretreatment/Strong Waste Program Cost
Category Annual Cost4 Annual Costs
Salary/Benefits $675,000 $1,050,000
Operations $25,0001 $40,0001
Misc. Expenses $140,0002 $218,0002
Amortized Equipment Cost $50,0003 $78,0003
Total $890,000 $1,386,000
1 Includes general office supplies, printing, postage, and annual public notices.
2. Interfund transfers, taxes and miscellaneous expenses.
3 Vehicle expense, computers, and sampling equipment (5 -year replacement).
4 9 FTEs.
5 14 FTEs.
The Wastewater Collection Service Unit is currently spending $150,000 on grease related
maintenance per year. In addition, the City had approximately $20,000 in grease related claims
filed in 1999. The Pretreatment Program has begun a grease monitoring program specifically
aimed at reducing grease loading to the sewer system. The final grease program has not been
finalized. The grease program could take any of the following shapes:
➢ Grease traps are inspected as part of pretreatment inspections. The inspector can require
traps to be pumped and issues fines if needed. Inspections continue to be scheduled at the
same priority as other pretreatment issues.
➢ Any business that has a grease trap would be required to send the pretreatment program
copies of receipts for pumping. Grease traps are inspected as part of pretreatment
inspections. The inspector can require traps to be pumped and issues fines if needed.
Inspections continue to be scheduled at the same priority as other pretreatment issues.
➢ Any business that has a grease trap would be required to send the pretreatment program
copies of receipts for pumping. Staff are dedicated specifically for the grease program.
Grease traps are inspected by the grease program and separate from pretreatment
inspections. The inspector can require traps to be pumped and issues fines if needed.
Pretreatment staff had previously contacted the Health District to discuss the possibility of the
Health District monitoring grease as a part of their restaurant program. The Health District is
willing to work with us, but has limited resources. The passage of I-695 has caused them to
reexamine their resource allocation. Yakima County has a limited role in grease management
and is not allowing grease trap pumping at landfills. There are services available that will pump
grease traps if it is handled correctly.
In a separate report prepared by the Wastewater Division entitled "Expanded Mandates from the
Environmental Protection Agency and the Department of Ecology" dated March 21, 2000, six
funding options for the Pretreatment Program were presented along with the anticipated financial
impacts to the City's business community.
Of the funding options presented, Option 4 was recommended for implementation. This option
appeared to offer the greatest flexibility, fairness to the business community, and promoted the
City Council policy of minimizing cost sharing from retail rate payers. Option 4 further meets
EPA's basic premise that the business responsible for the potential to cause pollution should be
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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responsible to off set the costs of the Pretreatment Program. The pros and cons of Option 4 were
set forth as follows:
Option 4 Cost Based (Recommended)
Option 4 was intended to keep the flat rate share for Minor Industrial User's. Those MIU's in
Significant Noncompliance will be monitored and billed on a more frequent basis. The
individual SIU's would be charged for costs incurred.
➢ Pros
• This is a flexible approach that assigns charges against businesses based on the actual
cost.
• The same percentage of the program is paid by small businesses.
• The individual business pays 100 percent of the City costs associated with that
business.
➢ Cons
• Two billing systems.
• Costs to businesses are based on the City's cost, not Ecology's fee schedule.
Table 6-21 identifies the anticipated permit fees to be assessed to commercial and industrial
facilities based on adoption of Option 4.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 64
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Table 6-21. Cost Based Pretreatment Program
Permit Type
Number
Complexity
Percentage of Resources
Total Cost/Year
Cost/Permit/Year
Commercial Laundry
2
1
0.0091
$4,543
2,271 43
Crop Preparing
g. 25,000 - <50,000 gins/yr
3
1
0 0136
$6,814
2,271 43
h. 50,000 - <75,000 bins/yr.
15
1
0.0682
$34,071
2,271 43
i 75,000 - <100,000 bins/yr.
1
1
0.0046
$2,271
2,271 43
j 100,000 - <125,000 bins/yr
3
1
0 0136
$6,814
2,271 43
Facilities Not Otherwise Classified
a. <1,000 gpd
0
b. 1,000 - <10,000 gpd
3
2
0 0153
$7,666
2,555.36
c 10,000 - <50,000 gpd
2
3
0 0153
$7,666
3,833 03
d. 50,000 - <100,000
2
3
0.0153
$7,666
3,833 03
Flavor Extraction
a. Steam Distilation
3
l
0 0136
$6,814
2,271 43
Food Processing
g. 500,000 - <750,000 gpd
2
2
0 0051
$2,555
2,555.36
Hazardous Waste Clean Up Sites
a. Leaking Underground Storage Tanks (LUST)
1 State Permit
3
1
0.0136
$6,814
2,271 43
Ink Formulation and Printing
a. Commercial print Shops
10
1
0.0455
$22,714
2,271 43
b. Newspapers
1
1
0 0046
$2,271
2,271 43
c. Box Plants
1
1
0 0046
$2,271
2,271 43
Metal Fabricators*
50
1
0.2273
$113,571
2,271 43
This is an estimate based on EPA pretreatment
categories.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 65
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o*
Table 6-21. Cost Based Pretreatment Program (Cont)
Permit Type
Number
Complexity
Percentage of Resources
Total Cost/Year
Cost/Permit/Year
Noncontact Cooling Water With Additives
a. <1,000 gpd
0
b 1,000 - <10,000 gpd
8
1
0 0364
$18,171
2,271 43
c. 10,000 - <50,000 gpd
3
1
0.0136
$6,814
2,271 43
Noncontact Cooling Water Without Additives
a. <1,000 gpd
0
b. 1,000 - <10,000 gpd
0
c. 10,000 - <50,000 gpd
3
1
0 0136
$6,814
2,271 43
d. 50,000 - <100,000 gpd
1
I
0.0046
$2,271
2,271 43
Photofinishers
a. <1,000 gpd
5
1
0 0227
$11,357
2,271 43
b 1,000 gpd and greater
1
1
0 0046
$2,271
2,271 43
Pulp, Paper and Paper Board
a. Fiber Recyclers
1
2
0.0051
$2,555
2,555.36
Timber Products
a. Log Storage
0
b. Veneer
0
c. Sawmills
0
d. Hardwood, Plywood
1
2
0.0051
$2,555
2,555.36
Vehicle Maintenance and Freight
a. <0.5 acre
0
b. 0.5 - <1 0 acre
1
1
0 0046
$2,271
2,271 43
Minor Industrial User (MW)
350
N/A
0.4203
$210,000
600.00
Total Permits
475
$499,600
HDR ENGINEERING, INC
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 66
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One of the permit conditions in the City's NPDES permit is to have legally binding
interlocal agreements for the enactment of a Pretreatment Program with the Terrace
Heights Sewer District and the City of Union Gap. These agreements are to insure the
complete and adequate implementation of the National Pretreatment Program. After
reviewing the legal authonty of the City, it was concluded that the City did not have the
authority to implement a Pretreatment Program in Terrace Heights and Union Gap. There
is language in the 4 -party agreement allowing Special Agreements for pretreatment.
After meeting with representatives from Terrace Heights, Union Gap, and WDOE, three
alternatives for pretreatment in Terrace Heights and Union Gap were identified:
➢ The City, for a fee, could manage the pretreatment program in outlying
jurisdictions.
➢ Terrace Heights and Union Gap could adopt the legal authority and implement
pretreatment in their jurisdictions.
➢ WDOE could continue to write permits in Terrace Heights and Union Gap.
Representatives from Terrace Heights and Union Gap would carry out other
pretreatment duties.
In alternative 2 or 3, the City would be responsible for oversight of the programs in the
other jurisdictions. Oversight costs incurred by the City of Yakima will be assessed to
Terrace Heights and Union Gap. Both Terrace Heights and Union Gap have selected
option 2 for implementation within their jurisdictional boundaries. The Special
Agreements outlining the responsibilities of Terrace Heights and Union Gap were
attached to the Wastewater Divisions report. The Special Agreements must be in place
by July 1, 2000 as a condition of the City of Yakima's NPDES permit.
In addition to the potential new revenue source available from the Pretreatment Program,
the Yakima Regional WWTP's Strong Waste Program also provides some revenues to
offset the costs of the Pretreatment/Strong Waste Program. Currently, 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 has adopted this threshold concentration in considenng
wastewater charactenstics that exceed this critena as meeting the definition of Strong
Waste and 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 appropnate 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
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IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
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surcharge rates for these businesses have been adjusted to reflect the actual strength
observed.
In updating the Cost -of -Service Report, we recommend that the Yakima Regional WWTP
staff reconsider the definition for "normal" domestic wastewater strength. As defined in
Section 4, the annual average per capita per day loading to the Yakima Regional WWTP
for BOD is 220 ppm and for TSS is 200 ppm. The maximum month average day per
capita loading was identified as 260 ppm for BOD and 230 ppm for TSS. These values
are more representative of the textbook description for "normal" domestic wastewater
strength which is generally stated as 200 ppm BOD and 200 ppm TSS. Lowenng the
threshold for the definition of Strong Waste will provide an equitable assessment of costs
to treat based on the actual volume and strength of the wastewater.
6.14.3 Laboratory Resource Requirements
Additional laboratory analysis will be required with the fully delegated Pretreatment
Program and the continuation of the strong waste program. In addition, the current
NPDES Permit requires testing for lower detection levels of metals and other constituents
in wastewater influent and effluent, as well as laboratory testing and evaluation of the
effluent receiving water (Yakima River). The Whole Effluent Toxicity (WET) testing of
the wastewater effluent, and the follow-up testing of the Toxicity Reduction Evaluation
(Ti/Re), if required, also adds to the laboratory staffing and space needs. Finally, the day-
to-day process control laboratory testing and reporting must be completed to keep the
facilities operational and meet NPDES permitting requirements. Acceptance of industrial
septage at the Yakima Regional WWTP would further add to the requirements for
sampling, testing, and reporting (1 additional laboratory technician).
The current laboratory staff includes 1 supervisor, 4 laboratory technicians, and 1
chemist. To meet future laboratory analysis requirements, the existing facilities will need
to be expanded with new staff positions added, or wastewater samples will have to be
sent to outside laboratories for analysis with a corresponding increase in professional
services, and with an increase in new staff positions.
Table 6-22 identifies the level of laboratory staff increase resulting from the fully
delegated pretreatment program, handling of industrial septage at the Yakima Regional
WWTP, and increased requirements of NPDES permit conditions. The implementation
of the Storm Water Management Program is further anticipated to add 1 full time
equivalent laboratory technician in addition to those shown in the table. The costs of the
laboratory technician for the Storm Water Management Program are included in Section
10. The added costs of laboratory space for the Storm Water Management Program are
included in this table.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 68
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Table 6-22. City of Yakima Laboratory Staffing and Laboratory Upgrades'
Category
Fully Delegated
Pretreatment
Industrial
Septage3
NPDES
Permit
Total
Operations
Personnel (1~ 1E)
1.5
3 0
0.5
5 0
Personnel (Dollars)
$112,500
$225,000
$37,500
$375,000
Equipment/Chemicals
$25.000
$35,000
$10,000
$70,000
Total Annual Cost
$137,500
$260,000
$47,500
$445,000
Capital
Laboratory Expansion/Equipment
$250,000
$200,000
$450,000
$800,0002
1 Additional Staffing/Laboratory Upgrades only
2. Laboratory Expansion/Equipment Capital Costs of $800,000 includes fully delegated pretreatment program,
increased requirements of NPDES, and Industrial Septage program. With Storm Water Management, the
laboratory Expansion/Equipment Costs increase to $1,000,000.
3. Based on one hundred 1,000 gallon septage loads per month with testing for BOD, TSS, pH, metals, and
petroleum hydrocarbons.
If the majority of the increased wastewater sampling for the fully delegated Pretreatment
Program was sent to outside laboratories for analysis, the total number of full-time
equivalent laboratory technicians would likely be reduced from 1.5 to 0.75 (for sampling
preparation and coordination with outside laboratories), in-house equipment and
chemicals could be reduced to the costs of sample bottles and shipping, with the costs of
outside professional services increasing significantly (800 samples/test at $800 per
sample equals $640,000).
A larger reduction in the need for additional full-time equivalent laboratory technicians
could be realized if all Industrial Septage wastewater sampling was sent to outside
laboratories for analysis. One laboratory technician would be responsible for sampling,
sample preparation, and coordination with outside laboratories. The cost of outside
professional services for 1,200 septage loads (1,000 gallons each), at $800 per sample,
would be $960,000 per year. In addition to the high cost of testing by the outside
laboratories, the results of the testing would likely take 3 to 5 days to receive, resulting in
an increase of storage of septage before treatment through the Yakima Regional WWTP.
The additional sampling and testing resulting from the increased requirements of the
NPDES permit conditions could be performed by an outside laboratory, but would likely
not result in a decrease of required full-time equivalent in-house staffing. One 0.5 full
time equivalent laboratory technician would be required for sample preparation and
coordination. The professional services costs for the outside laboratory for the low
detection limits required by the permit are expected to cost $1,800 each, with a total
annual cost of $86,400 (4 samples per month).
Approximately 30 percent of the laboratory expansion/equipment costs could be reduced
if the wastewater samples were sent to an outside laboratory. The remaining 70 percent
of the laboratory expansion/equipment costs are needed to meet current operational
requirements for NPDES reporting and process control, provide for increased sample
storage, sample preparation, and chain -of -custody reporting, and to meet the increased
sampling and testing of the Storm Water Management Program.
HDR ENGINEERING, INC
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER TREATMENT, October 6, 2000
Page 69
•
•
DRAFT
City of Yakima
Mandatory Wastewater Facilities Plan
SECTION 7
Aeration Basin Structural
Evaluation
October 2000
prepared by:
Grady Stephens
Dan Harmon
HDR Engineering, Inc.
in Association with
Landau & Associates, Inc.
reviewed by:
John Koch
Tony Krutsch
City of Yakima
•
•
DRAFT
TABLE OF CONTENTS
7.1 Introduction 1
7.2 Evaluation Findings 1
7.3 Recommended Solutions 4
INSERT A 7
HDR ENGINEERING, INC.
CITY OF YAKIMA
AERATION BASIN STRUCTURAL EVALUATION, October 6, 2000
Page i
DRAFT
• City of Yakima
•
SECTION 7
Aeration Basin Structural Evaluation
7.1 Introduction
Failing concrete within Aeration Basin No. 4 at the Yakima Wastewater Treatment Plant
(WWTP) has been observed since 1990. Previous repair efforts have not been entirely
successful. As a result of the concrete problems within the basin, the City elected to
remove the basin from service until the source of the cracking and spalling of the concrete
problem could be identified and corrective action taken. This Section presents the
recommended repair actions for correction of the localized concrete failures.
A field structural evaluation was conducted on July 28, 1999 and July 29, 1999 by
Landau Associates and HDR Engineering, Inc. to evaluate the basin floor/foundation
concrete and subsurface conditions and to determine the reason for concrete failures
associated with the floor slab, concrete topping and footing. The results of the field
investigation are presented in the Landau Associates Report entitled "Geotechnical
Engineering Evaluation Aeration Basin No. 4, Yakima Wastewater Treatment Plant,
Yakima Washington, October 7, 1999."
7.2 Evaluation Findings
The field evaluation determined that the observed cracks and voids within the basin
concrete at localized areas along the basin north wall are most likely caused by defects in
the mixing and placing of the original concrete wall footing. No significant signs of
subgrade instability beneath either the existing wall footings or the floor slab were
observed. A repair to previous concrete problems was completed in 1987. The repair
consisted of placing a flexible membrane liner over the perimeter Joint between the
concrete topping and the main wall footing (See Photo 1). The field evaluation
confirmed that these repairs have performed well. A short section (approximately 4 to 8
FT in length along the north wall) has separated at its edges (See Photo 2). The location
where the concrete failures are occurring are shown on Figure 7-1 and detailed in Photos
1 & 2. The concrete topping slab has, in several locations, pulled the lower footing cover
concrete away along a shear plane at the reinforcing steel.
HDR ENGINEERING, INC.
CITY OF YAKIMA
AERATION BASIN STRUCTURAL EVALUATION, October 6, 2000
Page 1
•
C
•
B
A
6 I 5 1 4 1 3 I 2 1 1 1
NJ I -ER
ti
(11
AERATION BASIN NO. 4 PLAN
SCALE. 3/16" = 1.-0'
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
D. HARMON
Drown
S. WHITE
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
I 1
THIS UNE IS ONE INCH WHEN
DRAWING IS FULL SIZE. IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
v
0
mu
O
Z
AERATION BAS N
NO. 4 CONCRL I E
FAILURE
Figure Number
7-1
\\ \
A j
15-2
1
LIMITS OF DETERIORATED z
CONCRETE. REQUIRES
REPAIR PER LIMITS OF WALL
\ FOURDAION/
15-2 INTERIOR SLAB
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SEE Q
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UMITS OF DETERIORATED UMITS OF
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REPAIR PER Q
Inn
L _J
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.�
AERATION BASIN NO. 4 PLAN
SCALE. 3/16" = 1.-0'
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
D. HARMON
Drown
S. WHITE
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
I 1
THIS UNE IS ONE INCH WHEN
DRAWING IS FULL SIZE. IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
v
0
mu
O
Z
AERATION BAS N
NO. 4 CONCRL I E
FAILURE
Figure Number
7-1
DRAFT
Photo 2 — Concrete failure occurring along
the leading edge of the topping slab.
The concrete in the failure areas is continuing to
deteriorate, and appears to be washing away below
the newer topping slab installed in 1987. See
Photo 3.
HDR ENGINEERING, INC.
CITY OF YAKIMA
AERATION BASIN STRUCTURAL EVALUATION, October 6, 2000
Photo 1 — Previous repair efforts in
1995 used a flexible membrane liner.
Continuing concrete detenoration has
caused these repairs to fail.
Photo 3 - Detenoration of the
existing concrete footing and slab
continues below the concrete
topping slab as identified by the
concrete core above.
Page 3
•
DRAFT
The investigation has also concluded that the concrete topping slab, placed as part of a
basin upgrade in 1987 over the original basin floor slab and footing, is in good condition
with only random hairline cracks. As shown in Figure 7-2, the concrete topping was
placed as a monolithic slab, spanning over the existing footing to intenor slab interface.
When originally constructed, a contraction joint was added to the topping slab at the
location of the point between the lower footing and interior slab.
7.3 Recommended Solutions
Past repairs have not been entirely successful, due to the continuing deterioration of the
existing concrete wall footing, interior slab, and the topping slab spanning the wall
footing to the interior slab interface. Portions of the newer topping slab overlie the
deteriorating concrete wall footing and interior slab below. The deteriorating concrete
areas, roughly delineated in Figure 7-1, should be removed to sound concrete and
replaced. This includes all topping concrete overlying the concrete sections requiring
removal (See Figure 7-2). It may be necessary to remove portions of the original interior
slab and excavate backfill to expose the face of the footing for visual inspection and to
facilitate repairs.
Removed concrete shall be replaced with 6 '/z sack, 4,000 psi concrete. Prior to placing
against existing concrete surfaces, the existing surfaces shall be cleaned and a bonding
agent applied. Should backfill be removed from below the footing level, all fill should be
replaced with clean gravel in a similar gradation to the material removed. Replaced
gravel fill should be compacted to at least 95 percent of the maximum dry density.
A new sawcut expansion/contraction joint, as shown in Figure 7-2, should be installed in
the topping slab at the existing wall footing to interior slab interface. This includes all
areas where the topping slab is replaced with new concrete topping. The sawcut joint will
allow the lower floor slab to move freely as it was originally designed and eliminate the
buildup of horizontal shear stress between the topping slab and lower footing and interior
concrete elements. An expandable water stop should be installed in the sawcut joint and
the joint should be sealed with a self -leveling chemical resistant sealant.
A basin hydrostatic test should be performed following concrete repairs to verify the
integrity of the repairs implemented. Due to the nature of the failure, the remaining
aeration basins should be evaluated for the need for repairs.
The opinion of probable cost for the rehabilitation of the existing aeration basins is shown
in Table 7-1.
HDR ENGINEERING, INC.
CITY OF YAKIMA
AERATION BASIN STRUCTURAL EVALUATION, October 6, 2000
Page 4
DRAFT
Table 7-1. Opinion of Probable Cost for Aeration Basin Rehabilitation
Unit
Opinion of Probable
Cost
Concrete Base Slab Repair (Basin 4)
Concrete Base Slab Repair (Basin 1 thru 3)
Aeration Basin Air Grid Support
Repair Coatings
Electrical (0%)
UC (0%)
Site Work and Yard Piping (5%)
Subtotal Costs
Contractor Overhead and Profit (15%)
Subtotal
Contingency (10%)
Subtotal
Sales Tax (8%)
Subtotal
Engineering, legal and fiscal (25%)
$70,000
$100,000
38,400
$168,000
0
0
$18,800
$395,200
$59,300
$454,500
$45,500
$500,000
$40,000
$540,000
$135,000
Total Opinion of Probable Cost
$675,000
HDR ENGINEERING, INC.
CITY OF YAKIMA
AERATION BASIN STRUCTURAL EVALUATION, Ortober 6, 2000
Page 5
•D
B
A
6 1 5 1 4 I 3 1 2
CONCRETE FAILURE
SHEAR PLANE AT
TOP OF REBAR
NOTE 1
f / 1
A.
SECTION
SCALE 3/8' =
NOTE 1
NOTF:
1 REMOVE. DISPOSE, REPLACE ALL DELETERIOUS AND FAILED
CONCRETE ON FOOTING TO SHEAR PLANE. REPLACE
WITH NEW CONCRETE. SAND BLAST EXISTING CONCRETE
AND APPLY BONDING AGENT PRIOR TO PLACEMENT OF
OF NEW CONCRETE.
1/2"
SAWCUT THROUGH TOPPING SLAB FULL
PERIMETER OF AREATION BASIN. INSTALL
EXPANSION/CONTRACTION JOINT WATER
STOP AND JOINT FILLER AS SHOWN
EXPANSION WATER STOP WITH
SELF—LEVELING SEALANT
TOPPING SLAB
INTERIOR SLAB
APPROXIMATE LOCATION OF
CONCRETE SHEAR PLANE
4
4
d
e
4
d
4
a
4
•
� • d
4
4
• •
4
d d
DETAIL
SCALE. NTS
FOOLING
n
FER
HDR Engineering, Inc.
CfTY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
D. HARMON
Drawn
S. WHITE
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
DRAWING 1S FULL SIZE. IF NOT
ONE INCH, SCALE ACCORDINGLY.
e
0
0
0
n
0
m
O
2
AERATION BASIN
NO 4 CONCRETE
FAILURE AND
RECOMMENDED
REPAIR DETAIL
Figure Number
7-2
•
DRAFT
INSERT A
Geotechnical Engineering Evaluation
Aeration Basin No. 4
Yakima Wastewater Treatment Plant
Yakima, Washington
October 7, 1999
HDR ENGINEERING, INC.
CITY OF YAKIMA
AERATION BASIN STRUCTURAL EVALUATION, August 28, 2000
Page 7
•
Report
Geotechnical Engineering Evaluation
Aeration Basin No. 4
Yakima Wastewater Treatment Plant
Yakima, Washington
October 7, 1999
Prepared for
HDR Engineering Inc.
500 108th Avenue NE, Suite 1200
Bellevue, WA 98004-5538
Prepared by
KA5,
LANDAU ASSOCIATES, INC.
130 2nd Avenue S. • Edmonds, WA 98020 • (425) 778-0907
•
TABLE OF CONTENTS
Page
INTRODUCTION 1
PROJECT BACKGROUND 1
SCOPE OF SERVICES 2
SITE CONDITIONS 3
Surface Conditions 3
Subsurface conditions 4
Groundwater 5
CONCLUSIONS AND RECOMMENDATIONS 5
DOCUMENT REVIEW AND CONSTRUCTION OBSERVATIONS 6
USE OF THIS REPORT 6
APPENDIX A, Field Explorations and Laboratory Testing
LIST OF FIGURES
Figure Title
1 Vicinity Map
2 Site Map
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•
INTRODUCTION
This report presents the results of Landau Associates' field investigations and provides
geotechnical engineering design recommendations for possible rehabilitation or repair of aeration basin
No. 4 at the wastewater treatment plant in Yakima, Washington. Cracking and spalling of the concrete
footing and floor slab has been observed for several years. Previous efforts to repair the damaged
concrete have not been entirely successful and the City of Yakima has requested that additional
evaluations be performed to determine the cause(s) and potential repair schemes. This report has been
prepared based on data collected dunng our field explorations, our previous studies at the site, and our
discussions with HDR Engineering, Inc. (HDR) and City of Yakima personnel.
PROJECT BACKGROUND
The Yakima Wastewater Treatment Plant is located in Yakima, Washington, adjacent to the
Yakima River, as shown on the vicinity map, Figure 1. The site plan, Figure 2, shows the major features
at the treatment plant. We understand the facility was originally constructed in 1936 and was
substantially expanded and modernized in 1965 and 1983. At the time the 1983 expansion was
completed, the major facilities consisted of four primary clarifiers, three primary and three secondary
digesters, some chemical storage/dosing structures, two trickling filters, three secondary clanfiers, four
aeration basins, two supernatant lagoons, sludge drying beds, and several support buildings.
In 1989, Landau Associates conducted subsurface investigations and provided geotechnical
design recommendations in support of the trickling filter pump station, dechlonnation building,
administration/laboratory building expansion, Yakima River outfall structure, and certain other planned
site improvements.
In 1995, Landau Associates conducted subsurface investigations and provided geotechnical
design recommendations in support of a new screenings building at the headworks, another pnmary
digester, and a third secondary clanfier. The new screenings building has been built and is operational
but the other proposed improvements have not been constructed. In addition, Landau Associates
conducted initial investigations to ascertain the probable cause(s) of localized settlement and concrete
slab cracking at vanous locations within the facility. The main areas of concrete distress consisted of the
sidewalks and slabs near the influent headworks, primary clarifiers, and the solids thickener building.
Our evaluations of these areas indicated that the movement was most likely attributed to poor filling and
compaction techniques during construction. The fill subsequently consolidated and settled and along with
portions of the overlying concrete.
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•
One additional area of concrete distress was located within aeration basin No. 4. Wall footing
concrete and the bottom floor slab had cracked and spalled at several locations, but the most severe
location was near the center of the north wall. Distressed concrete was present in 1990 when several
cores were removed (by others) and evaluated for compressive strength. Compressive strengths were also
correlated to Windsor probe tests conducted concurrently. Test results showed concrete strengths
exceeding 3,500 psi. At the time of our other services in 1995, Landau Associates included in our scope a
study of the concrete quality and subsurface investigation to evaluate soil and groundwater conditions. A
team of HDR and Landau Associates engineers reviewed data from previous studies and conducted a
visual evaluation of the affected basin and determined that the distresses were most likely attributed to
defects in the concrete. No significant signs of subgrade instability beneath either the wall footings or the
floor slab were noted and the need to continue with the subsurface investigation was deemed unwarranted
at that time. The footings and floor slab were repaired in 1995 by cleaning and patching areas of spalled
concrete and installing a flexible membrane over the perimeter joint between the floor slab and the wall
footings.
SCOPE OF SERVICES
Our services were provided in accordance with the scope of services outlined in our June 11,
• 1999 proposal to HDR. The specific scope of services included the following tasks:
• A site reconnaissance of aeration basin No. 4
• Cutting and coring the concrete floor slab in four locations to gain access to the subsurface
soil and wall footing
• Hand excavating and drilling a test bonng at the two openings located beyond the edge of the
wall footing
• Logging each exploration as to the thickness and depth of each soil unit encountered and
describing the soil in general accordance with the Unified Soil Classification System (USCS)
• Limited laboratory testing
• Engineering analyses in support of our conclusions and recommendations
• Submission of this geotechnical report summarizing the results of the field explorations,
along with our engineering conclusions and recommendations.
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SITE CONDITIONS
The following sections provide a summary of existing conditions observed at the site, a brief
description of the subsurface exploration and geotechnical laboratory testing program, and a summary of
near -surface soil and groundwater conditions encountered in the explorations.
SURFACE CONDITIONS
The interior dimensions of aeration basin No. 4 are approximately 93 ft long by 60 ft wide by 28
ft deep. The original floor slab design consisted of an 8 -inch thick concrete slab with #5 steel reinforcing
bars at 12 -inch spacing in each direction with a minimum of 2 inches of clearance from the top of slab.
The slab was keyed flush into the wall footings on all sides which are 2 ft 9 inches thick. A pressure
relief system, consisting of 11 pop-up pressure relief valves (PRVs) in the floor of each basin, flap valves
in the exterior walls, perforated drain pipes located under floor slabs and wall footings and around the
penmeter of the basins, and two sumps with groundwater pumps at the northwest and southeast corners,
was installed during construction to prevent damage from excessive hydrostatic pressures due to unequal
water levels.
Subsequent to the initial construction, a topping slab was placed over the original slab and most
of the wall footings, leaving a 12 -inch wide gutter around the perimeter. The slab varies in thickness
from about 7 inches in the center to about 3 inches at the edges. The PRVs were kept functional by
placing a PVC pipe sleeve around each valve that extends flush with the topping slab. The topping slab
appears to be in good condition with only random hairline cracks.
The repair accomplished in 1995 consisted of placing a flexible membrane over the penmeter
joint between the topping slab and the wall footing. The concrete surfaces were cleaned and patched
where needed pnor to installing the membrane. A typical concrete grout was used for patching and for
anchoring the edges of the membrane. For the most part, the membrane still appears to be in good
condition. The pnmary exception is a short section (about 4 to 8 ft long) located near the center of north
wall where the grout and membrane have separated from the footing. The biggest separation is about 1/4 -
inch wide and occurs where the footing had been patched.
As part of our 1999 field explorations, two holes (at locations AB4-1 and AB4-2 shown on
Figure 2) were cut through the topping and original concrete slabs to visually assess concrete integrity and
to access the subgrade soil. The holes were located adjacent to the center (north) wall footing so that the
face of the footing could also be observed. At AB4-2, a 2 -ft by 3 -ft rectangular hole was cut out with a
diamond -tipped wall saw. A 20 -inch diameter hole was cut with a diamond -tipped barrel corer at AB4-1.
The change in equipment was made due to the slow progress accomplished by the wall saw and because
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LANDAU ASSOCIATES
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the concrete was slightly thicker than the saw's capacity. The section to be removed was freed from the
surrounding concrete by hand chiseling. The cut pieces were lifted out by crane and set on the ground
along the south side of the basin. The pieces of topping slab and original floor slab concrete appeared to
be structurally sound. Plastic sheeting was encountered underlying the original floor slab. A 1/4 -inch
thick layer of soft silt was present on top of the plastic sheeting. It appears that the subgrade material has
settled about '/4 inch at the two exploration locations.
At the request of HDR, two 6 -inch diameter cores were cut from the topping slab above the north
wall footing near AB4-1 and AB4-2. The core near AB4-1 was extended down to the top layer of
reinforcing steel in the footing. A '/4 -inch wide gap was observed between the topping slab and the
footing at both of the core locations and another void was encountered at the reinforcing steel in the core
near A134-1. The voids were partially infilled with coarse sand and fine gravel. Also, a longitudinal
crack was observed at about mid -height in the face of the wall footing at AB4-2.
SUBSURFACE CONDITIONS
Soil and groundwater conditions below the aeration basin floor slab were explored on July 28 and
29, 1999 by hand excavating and then auger drilling two borings, AB4-1 and AB4-2, to depths of
between about 6 and 8 ft below the top of slab grade, at the approximate locations shown on Figure 2. A
skid -mounted Mobile B-24 drill rig was used to accomplish the borings. Representative soil samples
were obtained from the borings at selected depths and returned to our laboratory for further classification
and limited testing.
Details of the exploration program are summarized in Appendix A of this report; summary logs
of the conditions encountered in the explorations are presented on Figures A-2 and A-3 in Appendix A.
A key to the terms and symbols used on the summary logs is included as Figure A-1.
Geotechnical laboratory testing consisted of natural moisture content determinations on all
samples from the bonngs. The results of the moisture content determinations are shown on the summary
logs in Appendix A of this report.
Soil conditions observed below the floor slab in explorations AB4-1 and AB4-2 consist of fill
overlying native alluvial deposits. The fill is composed of about 3 ft of loose to medium dense, silty,
coarse gravel. The gravel is typical "drain rock" that is well rounded and of relatively uniform size, about
Y4 to 11/2 inch in diameter, and appears to have been placed as part of the under slab drainage system. The
silt is dark brown in color.
The fill extends to the base of the wall footing. Below this depth a very dense, sandy gravel with
silt and cobbles was encountered. The soil was wet and its color varied from gray and dark brown to light
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orange -brown. The native matenal is consistent with alluvial terrace deposits in the area. Each boring
was terminated when the drill ng could no longer advance through this dense material
Groundwater
Groundwater was encountered in the explorations at a depth of about 3 ft below the top of floor
slab. Based on information from City of Yakima personnel and our previous explorations, the regional
groundwater table dunng the summer irrigation season is substantially higher than the bottom of the
aeration basin floor slab elevation. Pressure relief valves in the floor slab, flap valves in the extenor
walls, and groundwater dewatering pumps were incorporated into the onginal construction to prevent
excessive hydrostatic pressure due to unbalanced water levels when the aeration basin is drained.
Groundwater is known to fluctuate due to seasonal variations, onsite dewatenng, and agricultural
irrigation in the area and as noted previously, the groundwater table is being depressed by groundwater
removal from the pump located at the southeast corner of the aeration basin.
CONCLUSIONS AND RECOMMENDATIONS
Based on our observations and interpretations of the data, it is our opinion that the concrete
distress is not the result of responses to subsurface soil or groundwater conditions. The observed cracks
and voids within the concrete are most likely the result of defect(s) in mixing or placing some of the wall
footing concrete.
It is possible, although not probable, that the observed separation between the topping slab and
the footing was caused by some slab uplift. Because of its limited extent and lack of observable distress
in the topping concrete, it appears more likely that the footing concrete continued to deteriorate after the
1993 repair and the observed gap is where decomposed concrete has been washed away. This supposition
also explains the gap observed between the topping slab and the footing in the two 6 -inch cores.
Because past repairs have not been entirely successful, we believe the most effective repair would
be to remove and replace the defective wall footing concrete. That portion of the topping slab overlying
the footing will also need to be removed to access the footing. It may also be necessary to remove
portions of the onginal slab and excavate the backfill to expose the face of the footing for visual
inspection and to facilitate repairs.
Removed backfill should be replaced with clean gravel of similar gradation to the existing
matenal or the removed gravel may be washed to remove most of the silt before backfilling it into the
excavation. The fill should be placed in relatively uniform horizontal lifts not exceeding 8 to 10 inches
thick, loose measure. Each lift should be compacted to at least 95 percent of the maximum dry density, as
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•
determined by the ASTM D 1557 test method or 75 percent of the relative density as determined by the
ASTM D 4253 and ASTM D 4254 test methods.
The floor slab may be reconstructed as a conventional concrete slab -on -grade, provided the
subgrade is properly prepared. To provide uniform support for the floor slab, we recommend that existing
fill be compacted to the requirements discussed above. The plastic sheeting between the gravel backfill
and the slab should be replaced to reduce the potential for fluid concrete to migrate into the gravel.
Although it does not appear that uplift due to hydrostatic forces is a pnmary cause of the current
distress, uplift is still of concern for continued operations. We recommend that all of the PRVs in the
floor and the flap valves in the exterior walls be cleaned, inspected, and repaired as needed each time the
basin is emptied. Correct functioning of the PRVs should be confirmed before returning the basin to
service by temporarily turning off the groundwater dewatering pump(s) and observing that groundwater
flows into the basin through the PRVs. Any other inflow locations should also be noted for possible
future repair.
We note that sediments currently accumulate in the pipe sleeves above the PRVs. If sediment
accumulation hinders the performance of the PRVs, we recommend that the PRVs be raised so they are
flush with the topping slab.
• DOCUMENT REVIEW AND CONSTRUCTION OBSERVATIONS
We recommend that Landau Associates be retained to review those portions of the plans and
specifications that pertain to earthwork construction to confirm that they are consistent with the
recommendations presented in this report. Typically, we recommend that geotechnical monitoring,
testing, and consultation be provided during construction to confirm that the conditions encountered are
consistent with those indicated by our explorations, to provide expedient recommendations should
conditions be revealed during construction that differ from those anticipated, and to evaluate whether
geotechnical -related activities comply with project plans and specifications and the recommendations
contained in this report. However, except for removal and replacement of backfill along the wall footing,
it appears that no significant earthwork will be performed. If requested, we would be pleased to provide
construction -related services to you.
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•
USE OF THIS REPORT
This report was prepared for the exclusive use of HDR Engineering Inc. and the City of Yakima
for specific application to this project. The findings, recommendations, and opinions presented herein are
based on the field explorations and observations. Within the limitations of scope, schedule, and budget,
the geotechnical services presented in this report were prepared in accordance with generally accepted
geotechnical engineering pnnciples and practices in this area at the time this report was prepared. We
make no other warranty either express or implied.
We appreciate the opportunity to provide these services and look forward to assisting you in the
future. Please contact us if you have any questions regarding the information contained in this report.
TDH/DAP/sms
No. 122008.40
LANDAU ASSOCIATES, INC.
By:
Timothy D. Huntting, P.E.
Project Engineer
and
co( Afr,
David A. Pischer, P.E.
Senior Associate
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Clarifier #2
Solids
Handling Bldg.
Ind. Waste,
Pumping Stn.
Primory
Clarifier #4
Trickling Filter Pumping Station
Primary
Clarifier #3
Digester
Control Bldg.
B-30 ®TP -71
4
North
Supernatant
Logoon
TTTTITTT
Sec.
Digester
#3
Influent
Bldg.
Sludge
Transfer Bld
Sec.
Digeste
#1
Primory
Clorifier #2
Primor
Digeste
#2
Sec.
Digest.
#2
Primary
Digester
#1
Yard'
Pumping
Sludge
Drying
Beds
Primary
Digester
#3
Boiler
Bldg.
Shop/Garage
Goroge
offices
Admin.
Building
Bose Mop Source: HDR, 1995.
0
100
200
Scale in Feet
Legend
i
AB4-1 E3oring Number and
Approximate Location (1999)
B-4 ® Boring Number and
Approximate Locotion (1995)
TP -3 ® Test Pit Number and
Approximate Location (1995)
Note: Explorations beyond 100ft from
aeration basin not shown
Site Mop
Figure 2
#1
Aei
ei AB4-1
#4
sa AB4-2
a ion
B`351n
#2
#3
Solids
Handling Bldg.
Ind. Waste,
Pumping Stn.
Primory
Clarifier #4
Trickling Filter Pumping Station
Primary
Clarifier #3
Digester
Control Bldg.
B-30 ®TP -71
4
North
Supernatant
Logoon
TTTTITTT
Sec.
Digester
#3
Influent
Bldg.
Sludge
Transfer Bld
Sec.
Digeste
#1
Primory
Clorifier #2
Primor
Digeste
#2
Sec.
Digest.
#2
Primary
Digester
#1
Yard'
Pumping
Sludge
Drying
Beds
Primary
Digester
#3
Boiler
Bldg.
Shop/Garage
Goroge
offices
Admin.
Building
Bose Mop Source: HDR, 1995.
0
100
200
Scale in Feet
Legend
i
AB4-1 E3oring Number and
Approximate Location (1999)
B-4 ® Boring Number and
Approximate Locotion (1995)
TP -3 ® Test Pit Number and
Approximate Location (1995)
Note: Explorations beyond 100ft from
aeration basin not shown
Site Mop
Figure 2
•
APPENDIX A
Field Explorations and Laboratory Testing
APPENDIX A
• FIELD EXPLORATIONS AND LABORATORY TESTING
FIELD EXPLORATIONS
Subsurface conditions below the aeration basin No. 4 floor slab were explored by hand
excavating and dnlling two soil bonngs at the locations shown on the site plan, Figure 2. The bonngs
were located in the field by pacing and taping from existing site features. The floor surface elevation
shown on the logs are estimated from the as -built aeration basin foundation plan by R.W. Beck and
Associates dated September 9, 1983.
The explorations were started by excavating the near -surface soil with hand implements. The
hand excavations were terminated at a depth of about 3 ft due to continued sloughing of gravel backfill.
The explorations were continued to depths of about 6 and 8 ft below the existing floor grade using skid -
mounted, hollow -stem auger equipment. Boretec Drilling, Inc. under subcontract to Landau Associates
drilled the bonngs.
The field explorations were observed by an engineer from our office who monitored exploration
activities, obtained representative soil samples, described the soil by both visual and textural examination,
and maintained a detailed record of subsurface soil and groundwater conditions. The soil encountered
was described in the field using the soil classification system illustrated on Figure A-1, in general
accordance with ASTM D 2488, Standard Recommended Practice for Description of Soils (Visual -
Manual Procedure). The boring logs are included in this appendix as Figures A-2 and A-3. These
exploration logs represent our interpretation of the field logs and the results of our laboratory
classification testing. Information presented on the summary logs depicts subsurface conditions only at
the specified location and date designated on the log. Soil and water conditions at other locations may
differ and changes may also result with the passage of time.
Disturbed samples of the soil encountered from the bonngs were obtained at frequent intervals
using either a 2.0 -inch or a 3 -inch outside diameter (OD) split -spoon sampler. The 3 -inch OD sampler
was used in an attempt to penetrate into the dense gravel. The sampler was driven into the undisturbed
soil ahead of the auger bit with a 140 -Ib hammer falling a distance of approximately 30 inches. The
sampler and hammer type used to obtain the soil sample is identified on the boring logs in this appendix.
The number of blows required to drive the sampler for the final foot of soil penetration, or part thereof, is
noted on the bonng logs adjacent to the appropriate sample notation.
10/8/99 S:\WPROC\I22\008\040\W WTP_APA.DOC LANDAU ASSOCIATES
A-1
•
•
LABORATORY TESTING
Laboratory tests were performed on representative samples of the soil encountered to evaluate
pertinent physical characteristics. The laboratory program was limited to visual inspection to confirm our
field soil descriptions and natural moisture content determinations.
Natural moisture content determinations of the samples were performed in general accordance
with ASTM D 2216 test procedures. The results from the moisture content determinations are indicated
on the logs, adjacent to the corresponding sample number.
Soil samples obtained from the explorations will be stored in our laboratory for 30 days after the
date of our final report. After that date, the samples will be disposed of unless arrangements are made to
retain them.
10/8/99 S:\WPROC\I22\008\040\WWTP_APA.DOC LANDAU ASSOCIATES
A-2
•
0
0
MAJOR
DIVISIONS
Soil Classification System
uscs
GRAPHIC LETTER
SYMBOL SYMBOL"
TYPICAL
DESCRIPTIONS(43)
COARSE-GRAINED SOIL
(More than 50% of material is
larger than No. 200 sieve size)
GRAVEL AND
GRAVELLY SOIL
(More than 50% of coarse
fraction retained on No. 4
sieve)
CLEAN GRAVEL
(Lithe or no fines)
D ° o O 0 °
00000
GW
Well -graded gravel; graveVsand mixture(s); little or no fines
Poorly graded gravel; graveVsand mixture(s); little or no fines
Silty gravel; graveVsand/silt mixture(s)
Clayey gravel; graveVsand/Gay mixture(s)
Do 0 0 0 0 0
GP
GRAVEL WITH FINES
(Appreciable amount of
fines)
"
"•
0 "
o
GM
•
z
GC
SAND AND
SANDY SOIL
(Morefraction thapassedn 50% ofthrough coarse
No. 4 sieve)
CLEAN SAND
(Little or no fines)
SW
Well -graded sand; gravelly sand; little or no fines
Poorly graded sand; gravelly sand; little or no fines
Silty sand; sandlsilt mixture(s)
Clayey sand; sand/day mixture(s)
SP
SAND WITH FINES
(Appreciable amount of
fines)
t
I
SM
SC
FINE-GRAINED SOIL
(More than 50% of material
is smaller than No. 200 sieve
size)
SILT AND CLAY
(Liquid limit less than 50)
ML
Inorganic silt and very fine sand; rock flour; silty or clayey fine
sand or clayey silt with slight plasticity
Inorganic Gay of low tc medium plasticity; gravelly day; sandy
Gay; silty Gay; lean clay
Organic silt; organic, silty day of low plasticity
CI-
OL
SILT AND CLAY
(Liquid limit greater than 50)
5):1))
MH
Inorganic silt; micaceous or diatomaceous fine sand
Inorganic clay of high plasticity; fat day
Organic day of medium to high plasticity; organic silt
CH
r,
OH
HIGHLY ORGANIC SOIL
PT
Peat; humus; swamp soil with high organic content
OTHER MATERIALS
GRAPHIC LETTER
SYMBOL SYMBOL
TYPICAL DESC
PAVEMENT
AC or PC
Asphalt concrete pavement or Portland cement pavement
ROCK
.' `�`
RK
Rock (See Rock Classification)
WOOD!
Sample Identification Number -inch
b 2.00 -inch O.D., 1.50 -inch I.D. Split Spoon
+--- Recovery Depth Interval c Shelby Tube
14— Sample Depth Interval d Grab Sample
J e Other - See text if applicable
Portion of Sample Retained 1 300 -Ib Hammer, 30 -inch Drop
for Archive or Analysis 2 140 -Ib Hammer, 30 -inch Drop
3 Pushed
4 Other - See text if applicable
WD
Wood, lumber, wood chips
DEBRIS
/O 0 0 4
n n n
DB
Construction debris, garbage
Notes:
1 USCS letter symbols correspond to the symbols used by the Unified Soi Classification System and ASTM classification methods. Dual letter symbols
(e.g., SM -SP) for a sand or gravel indicate a soil with an estimated 5-15% fines. Multiple letter symbols (e.g., ML/CL) indicate borderline or multiple soil
classifications.
2. Soil descriptions are based on the general approach presented in the Standard Practice for Description and Identification of Soils (Visual -Manual
Procedure), as outlined in ASTM D 2488. Where laboratory index testing has been conducted, soil classifications are based on the Standard Test
Method for Classification of Soils for Engineering Purposes, as outlined in ASTM D 2487
3. Soil description terminology is based on visual estimates (in the absence of laboratory test data) of the percentages of each soil type and is defined as
follows: Primary Constituent: >50% - "GRAVEL," "SAND," "SILT" "CLAY," etc.
Secondary Constituents: >30% and <50% - "very gravelly," "very sandy," "very silty," etc.
>15% and <30% - "gravelly," "sandy," "silty," etc.
Additional Constituents: > 5% and <15% -'With gravel," "with sand," With silt," etc.
< 5% -"trace gravel," "trace sand," "trace silt," etc., or not noted.
Soil Classification System and Key
Figure A-1
Drilling and Sampling Key
SAMPLE NUMBER & INTERVAL SAMPLER TYPE
Field and Lab Test Data
Code Description
a 3.25 inch O.D., 2.42 I.D. Split Spoon
Code
PP = 1.0
TV = 0.5
PID = 100
W = 10
-200 = 60
GS
AL
GT
CA
Description
Pocket Penetrometer, tsf
Torvane, tsf
Photoionization Detector VOC screening, ppm
Moisture Content, °A
Material smaller than No. 200 sieve, %
Grain Size - See separate figure for data
Atterberg Limits - See separate figure for data
Other Geotechnical Testing
Chemical Analysis
i
Sample Identification Number -inch
b 2.00 -inch O.D., 1.50 -inch I.D. Split Spoon
+--- Recovery Depth Interval c Shelby Tube
14— Sample Depth Interval d Grab Sample
J e Other - See text if applicable
Portion of Sample Retained 1 300 -Ib Hammer, 30 -inch Drop
for Archive or Analysis 2 140 -Ib Hammer, 30 -inch Drop
3 Pushed
4 Other - See text if applicable
Groundwater
Q
ATD
Approximate Water Elevation At Time of Drilling (ATD) or On Date Noted.
Groundwater levels can fluctuate due to precipitation, seasonal conditions, and
other factors.
Soil Classification System and Key
Figure A-1
AB4- 1
SAMPLE DATA
SOIL PROFILE
GROUNDWATER
n
a)
0
0
0)
. 0)
E 0.
00
Z Ti I- 0
C.) Z Zr.) LL ' E.
-
aG) Q 0) z N
EE E 3 Dc
co cd U) m 2 U
Graphic Symbol
Drilling Method. Hollow -stem Auger
Ground Elevation (ft) 976 30 (MSL)
Water Level
1
u)
0
0
x
0
14
►4
b2
b2
a
13
110/
7"
50/
3"
W=6.6
W=9.3
PC
0
c
c
c
c
c
c
c
c
0
0
0
0
0
0
0
0
0
GM
Floor slab: 4 -inch topping slab with welded wire
fabric and 8.5 -inch original slab with #5 bars
on 12 -inch centers underlain by plastic
sheeting (apparent vapor barrier)
- approximately 1/4 -inch thick layer of wet silt
present between bottom of slab and plastic
- approximately 1/4 -inch gap between bottom
of slab and underlying gravel
Dark brown, silty GRAVEL with some sand
(loose, moist to wet) (Fill)
c
c
c
c
c
0
0
0
0
0
GM
Boring Completed 07/29/99
Total Depth of Boring = 5.8 ft.
Brown, sandy GRAVEL with silt and cobbles
(very dense, wet)
Boring terminated due to practical refusal in
very dense gravel.
Notes: 1 Stratigraphic contacts are based on field interpretations and are approximate.
2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions.
3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols.
ATD
Log of Boring AB4- 1
Figure A-2
AB4- 2
SAMPLE DATA
SOIL PROFILE
GROUNDWATER
—0
—2
—
�_
- -
r)-6
)-
-
3 _
s -
-
-
J -
j-8
i -
-
ii_
.
J -
Y -
D -
'a
J -
D-10
cn
�pp -
Qr
m
U-
m -
8-
a
m
E-
Y
c-
c
w
C
=-14
c
m
$
N
E
Z
L a C)
. E c
_
o (iu V)o5
d
a—
a.
E
U)
ti
V)
3
m
c
r C)
•w-, t
20
.0
E
t
a
m
0
0
to
rn
U
n
Drilling Method Hollow -stem Auger
>
N
m
Ground Elevation (ft) 976 30 (MSL)
1
4
2
3
b2
b2
r b2
1186"
88/0
100/
4"
W=9 7
W=11
W=9.3
PC
Floor slab: 4 -inch topping slab with welded wire
fabric and 8.5 -inch original slab with #5 bars
on 12 -inch centers underlain by plastic
sheeting (apparent vapor barrier)
a
ATD
-
_
—
_
-
_
_
-
-
—
-1
-
-
-
-T
_
_
) a
<
) 0
7 0
� o
<
7 o
7 0
7 C
D a
< c
<
GM
°
0
0
o
0
o
0
0
0
Dark brown, silty GRAVEL with some sand
(loose, moist to wet) (Fill)
a
<
c
<
C_
GM
°
0
0
Brown, sandy GRAVEL with silt and cobbles
(very dense, wet)
> c
<
7 c
<
) C
<
7 c
<
7 C
<
7 C
<
7 c
7 < c
7 o
GM
°
o
o
0
o
o
0
o
n
Brown and dark gray, sandy GRAVEL with silt
and cobbles (very dense, wet)
Boringterminated due topractical refusal in
very dense gravel.
Boring Completed 07 29/99
Total Depth of Boring = 7.8 ft.
— 12
_
_
Notes: 1 Stratigraphic contacts are based on field interpretations and are approximate.
2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions.
3. Refer to "Soil Classification System and Key" figure for explanation of graphics and symbols.
—
-
-
-
-
—
-
.
_,
—
-
—
0
Log of Boring AB4- 2
Figure A-3
DRAFT
City of Yakima
Mandatory Wastewater Facilities Plan
SECTION 8
Gas Utilization and Cogeneration
October 2000
prepared by:
Paul O'Brien
reviewed by:
John Koch
Tony Krutsch
HDR Engineering, Inc. City of Yakima
•
DRAFT
Table of Contents
8.1 Introduction 1
8.2 Current and Future Gas Production 1
8.3 Current and Future Heating Requirements 3
8.4 Gas Utilization for Heating Alternatives 5
8.5 Discussion 8
8.6 Recommendations 9
HDR ENGINEERING, INC.
CITY OF YAKIMA
GAS UTILIZATION AND COGENERATION, October 6, 2000
Page i
•
DRAFT
City of Yakima
SECTION 8
Gas Utilization and Cogeneration
8.1 Introduction
The purpose of this section is to look at the options for the use of methane gas produced
in the anaerobic digesters and make recommendations for future utilization of the gas.
Issues will include:
➢ Current and future anaerobic digester gas production
➢ Current and future heating requirements to be satisfied by boilers fired by digester
gas or alternative fuels
➢ Cogeneration
➢ Options for system modifications
A schematic of the existing boiler/hot water system is shown in Figure 8-1.
8.2 Current and Future Gas Production
Table 8-1 below summarizes both the current and estimated future average daily gas
production from the anaerobic digester system.
The recorded values of gas production for the months of April 1998 through April 1999
reflect periods when at least one digester was out of service. One digester was out of
service for significant periods during the months of January through April of 1999.
The gas production data for January through April 1999 may be considered the most
recent reliable data.
HDR ENGINEERING, INC.
CITY OF YAKIMA
GAS UTILIZATION AND COGENERATION, October 6, 2000
Page I
6
5
4
3
2
SHOP AND GARAGE 5
STORAGE BUILDING HWS
HWR
HWR
SHOP AND GARAGE HWS
PRIMARY DIGESTER
CONTROL AND
SOLIDS HANDLING
BUILDING
HWS
HWR
TO AND FROM STAFF BUILDING
HWS
HWR INFLUENT BUILDING
ADMIN. BUILDING AND
HWS
HWR SLUDGE TRANSFER
BUILDING
1V24
1V21
1V22
HWC 241
HWC 242
HWR /
BOILER 2
HOT WATER
CIRCULATION PUMPS
BOILER BUILDING
AREA 9A1
BOILER 1
1V16
HOT WATER BOOSTER PUMPS LEGEND
SERVICE PUMP NUMBER —1><—
SOLIDS HANDLING BLDG. HWS -240 —101—
SHOP/GARAGE
HH-SHOP/GARAGE HWB-241 -.(__
ADMIN/INFL BLDGS. HWP-102
SLUDGE TRANSFER BLDG. HWP-101
GATE VALVE
PLUG VALVE
GLOBE VALVE
MOTOR OPERATED THREE
WAY VALVE
BOOSTER PUMP
NOR Engineering, Inc.
CfTY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
P OBRIEN
Drown
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.
0
Description
Z
HOT WATER
SYSTEM SCHEMATIC
Figure Number
8-1
•
DRAFT
Table 8-1
Digester Gas Produced in cubic ft/day
Average Day
Year
Actual Gas
Produced
(ft3/day)
Actual Available
Biogas Energy,
MBH
Estimated Gas
Produced
(ft3/day)
Estimated Available
Biogas Energy,
MBH
April '98 thru
March '99
99,400
2486
Jan. '99 thru April
'99
128,600
3215
2000
-
-
159,900
3,997
2005
-
-
168,700
4,218
2010
-
-
178,700
4,468
2020
-
-
191,100
4,778
The estimated values of gas production for the future years are based on projections of
increased wasteloads to the plant. These projections were contained in Section 4 and are
based on expected primary and secondary sludge loads to the anaerobic digesters. For the
purposes of this section, estimated values are anticipated to reflect future values.
8.3 Current and Future Heating Requirements
Table 8-2 below summarizes the calculated design heating requirements for the waste
treatment plant as a whole, including both building heating requirements and sludge
heating requirements. Future heating requirements due to an expansion of the
administration building are also presented.
HDR ENGINEERING, INC
CITY OF YAKIMA
GAS UTILIZATION AND COGENERATION, October 6, 2000
Page 3
•
DRAFT
Table 8-2
Hot Water Heating System
Building Name
Design Heatingt
Requirements MBH
Future Heating Requirements
MBH (2020)
Administration
725
725
Influent Building
305
305
Sludge Transfer Building
150
150
TFPS Building
51
51
CL2 Building
236
236
Dechlor Building
69
69
Solids Handling Building
479
479
Digester Building
175
175
Sludge Heating
2,464
2,865
Garage/Shop
340
340
Garage/offices
200
200
Headworks Building
475
475
Storage Building
579
579
Existing Total
6,248
Administration 3500 sf Addition
240
Future Total
6,889
'Based on connected load with outside temperature of 5 Deg F and minimum inside temperature of 70 Deg F
Of the total 6,248 MBH current heating requirements, 2,464 is required for sludge heating
or 39.5 percent, with the remaining 60.5 percent required for building heat. These
percentages will not change significantly in the future even with the Administration
Building expansion and higher sludge heating requirements.
Each of the two existing boilers is rated at 5,230 MBH (input). Assuming 80 percent
efficiency the output is 4,184 MBH or 8,368 MBH total for both boilers. This total is
more than the anticipated heating requirements through the year 2020, including the
present design heating load without redundancy. The existing boilers are adequate to
provide the necessary hot water for heating.
The local Clever -Brooks Boiler representative is Cole Industrial Inc. According to Cole
Industrial, the existing boilers are in excellent condition and are anticipated to remain in
service for at least another ten years.
If the plant should decide to switch the anaerobic digesters to thermophillic operation in
the future, the total heating load required will be approximately 7,873 MBH versus 2,865
MBH. The total heating requirement of 11,897 MBH will exceed the capacity of the
existing boilers.
HDR ENGINEERING, INC.
CITY OF YAKIMA
GAS UTILIZATION AND COGENERATION, October 6, 2000
Page 4
•
DRAFT
8.4 Gas Utilization for Heating Alternatives
Sources for Fuel
The pnmary source of fuel for the boilers is digester gas. When the digesters do not
produce enough gas to meet the heating requirements for the plant, the staff manually
changes the boiler fuel to backup fuel. The backup fuel for the boilers is fuel oil. At
present there are times when the digesters do not produce enough gas to meet the heating
needs of the facility requiring manual change over to fuel oil.
An alternative to fuel oil as a backup fuel would be natural gas. Natural gas would allow
the change over from digester gas to natural gas to occur automatically. An automatic
change over would decrease the amount of digester gas sent to the flare because all
digester gas would be utilized when it was available.
When changing the existing boilers over from fuel oil to natural gas the current emission
standards of 30 PPM NOx and 50 PPM CO levels will have to be met. The existing
boilers, at the present time, do not have to meet these requirements as they are considered
"grandfathered" into the codes.
Since natural gas is not available on the site, a supply line would have to be extended to
the site by the local gas utility. Discussions with the utility have indicated they are not
interested in extending a new service to the plant. One of the major reasons is use of
natural gas will be sporadic and it will not be cost-effective for them to serve the plant in
this manner.
Another alternative is to convert the existing boilers to propane/digester gas. The current
emission standards will have to be meet just as with the natural gas conversion. The
conversion piping and appurtenances have an estimated cost of $20,000 per boiler. The
propane storage tank could be obtained at no cost. A vaporizer would be required
between the storage tank and the boiler at an estimated cost of $7,000 with piping and
appurtenances.
The cost of propane at this time is $0.45 per gal plus $0.07 per gal transport cost plus
$0.06 per gal lay -in price for a total of $0.58 per gal or $0.637 per therm (100,000 BTU).
The cost of fuel oil in Yakima is currently $1.09 per gal or $0.779 per therm.
Another option investigated was the use of used crankcase oil. The boiler manufacturers
will not guarantee the performance of the boiler unless the crankcase oil is mixed with #2
fuel oil. The required mix is 10 percent used oil to 90 percent fuel oil. Emissions are
also a concern with the fuel mixture. There is a boiler manufactured that is designed to
burn used oil. The largest size available is 520 MBTUH output and requires 5.0 gals per
hour. The discussion has been to add new a boiler capable of producing 4,184 MBTUH
output. That would require a total of 8 used oil boilers and a supply of 50 gals of used oil
per hour.
HDR ENGINEERING, INC.
CITY OF YAKIMA
GAS UTILIZATION AND COGENERATION, October 6, 2000
Page 5
DRAFT
Add A New Boiler - Dedicated to Fuel Oil
• This alternative would add a new boiler to the existing boiler system that would be fired
primarily on the backup fuel (fuel oil or propane). The new boiler would be capable of
being fired on digester gas if necessary. This unit would be used for supplemental
building heat during those periods when supplemental fuel is required and serve as a
backup to the existing boilers in case of emergency. The existing boilers would be base
loaded on digester gas to heat the digesters with the remainder going to building heat as
needed. Since the digesters will always require heating even when building heating
requirements are zero, digester gas will be used to its fullest extent.
As noted, the addition of the new boiler will provide backup for the existing boilers,
which are reaching approximately 30 years of age. While the units are considered to be in
good condition, the new boiler will be a good addition to the boiler system in the event of
an unseen major problem with one of the older units.
The new boiler would be the same size (5,320 MBH) as the two existing boilers and be
installed in the same building. With 80 percent efficiency, the output of the three boilers
would be 12,768 MBH. This total capacity would satisfy existing demands and allow for
future expansion of the plant's heating needs beyond 2020 even with the digesters
operated in the mesophillic range.
Cogeneration
• Cogeneration at the Yakima Wastewater Facilities has been investigated previously. The
opinion of probable cost associated with the installation of a natural gas/propane/digester
gas engine generator set is shown in Table 8-3.
•
The associated analysis is presented in Table 8-4.
HDR ENGINEERING, INC.
CITY OF YAKIMA
GAS UTILIZATION AND COGENERATION, October 6, 2000
Page 6
r
DRAFT
Table 8-3
Cogeneration Opinion of
Probable Cost
Unit
Opinion of Probable
Cost
Engine Generator/Structure
Electrical (15%)
UC (7%)
Site Work and Yard Piping (20%)
Subtotal Costs
Contractor Overhead and Profit (15%)
Subtotal
Contingency (20%)
Subtotal
Sales Tax (8%)
Subtotal
Engineering, legal and fiscal (25%)
Total Opinion of Probable Cost
$450,000
$67.500
$31,500
$90,000
$639,000
$95,900
$734,900
$147,000
$881,900
$70,600
$952,500
$238,100
$1,190,600
Table 8-4
Cogeneration Analysis
Year
Electricity
Generated
Cost of
Electricity
Value
$/Year
Maintenance'
Cost
Total
Value
Simple
Payback
KwH
$/KwH
$/Year
Years
2000
175
0 053
81,249
57,500
23,749
50.1
2010
212
0.053
98,400
57,500
40,900
291
Generator Capital Cost
1,190,600
'Includes equivalent of 0.50 maintenance staff per year plus service costs of $20,000 per year
The payback for the generator installation is not cost-effective based on the values in
Table 8-4. The payback will actually be of greater duration since the value of the fuel
required to make up the difference between the recovered heat and the heat required to
heat the buildings and the digesters has not been included in the evaluation.
Cogeneration systems are generally good public relations. They indicate that the
municipality is concerned about energy conservation and is doing something to keep costs
in line. Plants with visible constantly operating waste gas flares often create negative
impressions with the public. Some gas must occasionally be flared even with
cogeneration systems.
Most plant operators and maintenance workers view cogeneration systems as an
intriguing and positive improvement to the plant and are interested in seeing the system
work. This can have a beneficial effect on the solids processing too as the digesters, gas
production, and sludge thickening all effect the operation of the cogeneration system.
HDR ENGINEERING, INC.
CITY OF YAKIMA
GAS UTILIZATION AND COGENERATION, October 6, 2000
Page 7
DRAFT
Piping Modifications
• The three-way valve that regulates the water temperature to the sludge heat exchangers
has been taken out of service. The purpose of the valve was to mix 180 DegF supply
water with return water to regulate the temperature of the supply at 150 DegF. Without
the regulating valve the temperature of the entire supply water system would have to be
150 DegF and not 180 DegF. If the average temperature in the entire system is dropped
to 150 DegF or below, then condensation in the boilers will occur. The average boiler
temperature should be 180 to 190 DegF. At this temperature condensation and corrosion
within the boiler and in the boiler stack will be minimized.
The hot water supply and return piping on the outside of the shop building is resting
directly on its' supports. Significant heat loss occurs through these supports. The supports
are exposed to the ambient temperature and heat is conducted from the piping to the
outside. This occurs on both the supply and return piping. The supports should be
lowered sufficiently to fit a spacer, either a block of hard wood or a high-density
insulation, between the support and the pipe. The thickness of the spacer should be the
thickness of the pipe insulation and the jacketing should be replaced around the outside of
the insulation and spacer. The jacketing should be continuous at the support with no
breaks.
8.5 Discussion
• The purchase price for a 4,184 MBTUH boiler fired with propane is $67,100. The
purchase price for the same boiler fired with fuel oil is $63,700. Freight for either boiler
is estimated at $4,500. The cost to convert the existing boilers to propane and installing
the low NOx conversion is $20,000 per boiler. The total for converting both boilers, with
piping would be $45,000.
Propane and the fuel oil cost is approximately the same at the present time. Last year
propane was $0.29 per therm and #2 fuel was $0.45 per therm. Two 2,000 -gal propane
tanks with dimensions of 41 inch round and 192 inch long would provide adequate
propane storage. The annual average propane usage, based on the last 4 years of backup
fuel usage, would have been 2,500 gals of propane.
The existing fuel storage tank may require replacement under future UST regulations. A
new 2000 gal fuel oil storage tank located above grade would cost approximately
$20,000. This storage tank would meet all of the current regulations for above grade
storage containers.
If propane is used as the backup fuel, the first cost of changing the existing boilers from
fuel oil to propane would be $45,000, as compared to $20,000 to replace the existing
underground fuel oil storage tank.
• The consideration of using used crankcase oil does not appear to be an acceptable option
with a conventional boiler due to the mixing requirements for guaranteed performance.
HDR ENGINEERING, INC.
CITY OF YAKIMA
GAS UTILIZATION AND COGENERATION, October 6, 2000
Page 8
DRAFT
• 8.6 Recommendations
Install a new boiler sized at same capacity as the existing boilers. The primary fuel
should be fuel oil with digester gas as backup. The piping arrangement should allow the
new boiler to either be supplemental to the existing boilers or be dedicated to heating the
buildings. See Figure 8-2.
The backup fuel for the existing boilers should remain fuel oil.
Install an above ground fuel oil storage tank if it becomes necessary to abandon the
existing below grade storage tank.
The three way valve used to control the temperature of the heating water to the digesters
should be placed back in service.
The pipe supports for the hot water supply and return piping located outside should be
adjusted to allow insulation to be added between the support and the pipe.
HDR ENGINEERING, INC.
CITY OF YAKIMA
GAS UTILIZATION AND COGENERATION, October 6, 2000
Page 9
6
5
4
3
SHOP AND GARAGE HWR
HWR
STORAGE BUILDING HWS
HWS
SHOP AND GARAGE S
PRIMARY DIGESTER
CONTROL AND
SOLIDS HANDLING
BUILDING
TO AND FROM STAFF BUILDING
HWS
HWR INFLUENT BUILDING
5 ADMIN BUILDING AND
HWS -
HWR S SLUDGE TRANSFER
a S BUILDING
NEW
VALVE
V VE
HWS
HWR
1V20/
VE
1 V21 \ \\AS /
1V22
NEW
VALVE �
1Vi
HWC 241
HWC 242
HOT WATER
CIRCULATION PUMPS
1V16
HWR
BOILER BUILDING
AREA 9A1
BOILEP 1
HOT WATER BOOSTER PUMPS
LEGEND
SERVICE PUMP NUMBER —1)"1—
SOLIDS HANDLING BLDG HWS -240
SHOP/GARAGE 1-IWB-241 -{
ADMIN/INFL BLDGS F-ISVP- 102
SLUDGE TRANSFER BLDG HWF'- 101
BOILER 2
GATE VALVE
PLUG VALVE
GLOBE VALVE
MOTOR OPERATED THREE
WAY VALVE
BOOSTER PUMP
hill
HDR Engineering, Inc.
CRY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
P OBRIEN
Drawn
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
I I
THIS UNE IS ONE INCH WHEN
DRAWING IS FULL SIZE. IF NOT
ONE INCH, SCALE ACCORDINGLY.
g"
0
O
Z
HOT WATER
SYSTEM SCHEMATIC
Figure Number
8-2
•
DRAFT
City of Yakima
Mandatory Wastewater Facilities Plan
SECTION 9
Biosolids Management
October 2000
• prepared by reviewed by
Tony Krutsch/Clint Dolsby John Koch
HDR Engineering, Inc. City of Yakima
•
•
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Table of Contents
9.1 Introduction 1
9.2 Federal, State, and County Regulations 1
9.2.1 Federal Regulations 1
9.2.2 Washington State Law 2
9.2.2.1 70.95 RCW: Solid Waste Management -Reduction & Recycling 2
9.2.2.2 70.95J RCW: Municipal Sewage Sludge — Biosolids 2
9.2.2.3 90.48 RCW, Water Pollution Control 2
9.2.3 Washington Department of Ecology and WAC 173-308 "Biosolids Management" 3
9.2.3.1 Pollutant Limits 3
9.2.3.2 Pathogen Reduction 4
9.2.3.3 Vector Attraction 6
9.2.4 Permits and Reporting Requirements 7
9.3 Sludge Quantity and Quality 8
9.4 Biosolids Disposal Program 10
9.4.1 Land Application Rates 10
9.4.2 Permits 11
9.4.3 Existing Land Application Site 11
9.4.4 Natural Selections Farms As A Back Up Site 13
9.4.5 Biosolids Equipment 13
9.4.5.1 Front End Loader 13
9.4.5.2 Ford Semi Truck/Trailer 14
9.4.5.3 Peterbilt Semi Truck/Mate Trailer 14
9.5 Biosolids Processing 14
9.6 Evaluation Process 18
9.6.1 Define Process Methodology and Evaluation Criteria 18
9.6.2 Identify and Screen Ideas 18
9.6.3 Detailed Development and Evaluation 19
9.7 Alternatives Development and Screening 19
9.8 Detailed Evaluation of Alternatives 21
9.8.1 Summary of Alternatives Developed 21
9.8.2 Design Criteria 22
9.8.2.1 Planning Horizon 22
9.8.2.2 Process Sizing Criteria 22
9.8.2.3 Flows and Loadings 22
9.8.3 Development of Opinion of Probable Costs 22
9.9 Biosolids Enhancement Options 23
9.9.1 Composting Alternatives 24
9.9.1.1 Windrow Systems 25
9.9.1.2 Static Pile Systems 25
9.9.1.3 In -Vessel Systems 25
9.9.2 Yakima Regional Experience in Composting 25
9.9.3 Chemical Treatment Alternative 26
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9.9.4 Alternatives Evaluation 26
9.9.5 Preliminary Recommendations 27
9.9.6 Sludge Enhancement Alternative Cost Estimates 27
9.10 Added Digestion 27
9.10.1 Alternatives Considered 29
9.10.1.1 Single -Stage Mesophilic Anaerobic Digestion 29
9.10.1.2 Two -Stage Mesophilic Anaerobic Digestion 31
9.10.1.3 Temperature -Phased Anaerobic Digestion 32
9.10.1.4 Pre-Pasteurization/Mesophilic Anaerobic Digestion 34
9.10.2 Alternatives Evaluation 35
9.10.3 Recommendations 35
9.11 Existing Facilities Needs 35
9.11.1 Solids Handling Building 35
9.12 Secondary Handling of Centrate Alternatives 36
9.12.1 Alternatives Considered 36
9.12.2 Alternatives Evaluation 37
9.13 Biological Dewatering/Drying Alternatives 37
9.13.1 Alternatives Considered 37
9.13.2 Alternatives Evaluation 38
9.13.3 Preliminary Recommendations 38
9.14 Polymer Addition Alternatives 38
9.14.1 Alternatives Considered 38
9.14.2 Alternatives Evaluation 39
9.15 Solids Handling Building Alternatives 39
9.15.1 Alternatives Considered 40
9.15.2 Alternatives Evaluation 40
9.15.3 Recommendations 45
9.16 Biosolids Utilization Alternatives 45
9.16.1 Design Criteria 45
9.16.2 Alternatives Descriptions 46
9.16.2.1 Historical Practice 46
9.16.2.2 Move the Treatment Facility 46
9.16.2.3 Continue the Current Method of Dewatering and Hauling 46
9.16.2.4 One -Year of Storage of Biosolids at the Plant Site 47
9.16.2.5 3 -Months of Storage of Biosolids at the Plant Site 47
9.16.2.6 3 -Months of Storage at Agricultural Fields and 1 -Week Storage at Plant Site.48
9.16.2.7 Landfill Disposal of Biosolids 48
9.16.2.8 Incineration of Pnmary and Waste Activated Sludge 49
9.16.2.9 Lime Stabilization of Solids 49
9.16.3 Alternatives Evaluation 50
9.16.3.1 Opinion of Probable Cost 50
9.16.3.2 Comparison of Options 52
9.16.4 Implementation 54
9.16.5 Recommendations 54
9.17 Current Staffing 55
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City of Yakima
SECTION 9
Biosolids Management
9.1 Introduction
The purpose of this section is to summarize the Yakima Regional WWTP program for
processing, handling, and utilizing biosolids produced from the treatment of wastewater from
the Yakima Urban Area.
The section identifies regulations that guide the Yakima Regional WWTP program for
biosolids utilization; identifies quantity and quality of biosolids; describes the solids
processing program following digestion; and discusses practices of land application. Current
operational issues as identified during workshops with the WWTP staff are incorporated into
the discussion.
Based on the information included in the historical evaluation, recommendations are
developed to address the anticipated increase in biosolids quantity from a growing service
area population; to mitigate current operational issues; and to address possible improvements
which may be implemented by the Yakima Regional WWTP to enhance the biosolids
utilization and reuse program.
9.2 Federal, State, and County Regulations
9.2.1 Federal Regulations
Regulations and guidance on sludge and biosolids utilization are set forth pnmarily in two
federal laws: the Water Pollution Control Act, and the Resource Conservation and Recovery
Act. These two laws provide the most specific direction for solid waste and biosolids
management
Section 405 of the Water Pollution Control Act directed the U.S. Environmental Protection
Agency (EPA) to formulate regulations to meet the legal requirements of the Act. In
response, EPA wrote 40 CFR, 257, 258, 501, and 503. 40 CFR 257 and 258 set minimum
criteria for municipal solid waste landfills. 40 CFR 501 specifies procedures for
implementing state developed and administered sludge management programs. 40 CFR 503
establishes standards for the final use of biosolids. The 40 CFR 503 standards include
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BIOSOLIDS MANAGEMENT - October 6, 2000
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pollutant limits, management practices, and operational standards which are used to produce
IIIbiosolids, and defines what is acceptable for final use.
•
•
The Resource Conservation and Recovery Act (RCRA) included provisions for the reuse of
solid waste resources, and disposing of solid waste products through well -conceived
programs. Sewage sludge was defined in the RCRA as a solid waste. In developing
guidelines for implementation of the RCRA, EPA identified 3 categories for: handling and
disposal of unstabilized sludges or sludges contaminated with toxic materials; criteria and
standards for solid waste disposal facilities such as sanitary landfills; and agricultural land
application criteria for unstabilized sludge application.
There are a number of other possible federal regulations and federal agencies which may
impact sludge handling and disposal practices. The Biosolids Management Plan prepared for
the City of Yakima in March 1993 provides a further description of other federal regulations
that the Yakima Regional WWTP may encounter.
9.2.2 Washington State Law
The Washington State Law has three chapters in the Revised Code of Washington (RCW)
which govern biosolids management: Chapter 70.95, 70.95J, and 90.48.
9.2.2.1 70.95 RCW: Solid Waste Management -Reduction &
Recycling
This law regulates "sewage sludge" as a solid waste. If sewage sludge meets the definition
found in this regulation, it is regulated as a solid waste along with other waste materials.
Sewage sludge or septage is prohibited from being disposed of in a landfill except on an
emergency basis. Sludge can be used for beneficial use at a landfill as intermediate or final
cover.
9.2.2.2 70.95J RCW: Municipal Sewage Sludge — Biosolids
This law has the greatest impact on biosolids and their beneficial reuse. Biosolids are defined
as "...municipal sewage sludge that is a primarily organic, semisolid product resulting from
the wastewater treatment process, that can be beneficially recycled and meets all requirements
under this chapter." The definition of biosolids includes septic tank sludge or septage as well
as municipal sewage sludge. The law required the Washington Department of Ecology
(WDOE) to implement a statewide biosolids management plan. It also provided for public
input into the permitting process, public education, and delegation of permitting to local
junsdictional health districts with WDOE reviewing the permit.
9.2.2.3 90.48 RCW, Water Pollution Control
This state law governs the protection of the waters of the state from pollution. It requires
sludge management compliance when sludge is directly discharged into the waters of the
state, land spreading operations are not following specified criteria, and activities involve
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BIOSOLIDS MANAGEMENT - October 6, 2000
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construction of digesters, dewatering equipment, drying beds, incinerators, etc. This law
authorizes WDOE to set a fee schedule and collect annual fees for issuing and administering
biosolids land application permits.
9.2.3 Washington Department of Ecology and WAC 173-308
"Biosolids Management"
The WDOE is the principal state agency for regulation and managing sewage sludge. WDOE
regulations establish minimum standards for solid waste sites, sanitary landfills, leachate, and
composting. With the promulgation of 70.95J RCW and WAC 173-308 "Biosolids
Management", biosolids were transformed from solid waste to a recyclable product if the
sludge meets certain minimum standards. WAC 173-308 is primanly based upon 40 CFR
503. This regulation covers standards, permitting, beneficial use, and fees associated with
Biosolids management.
Biosolids "...is the term used... to refer to municipal sewage sludge or septage that has been
or is being treated to meet standards so that it can be applied to the land." These standards
consist of: pollutant limits; pathogen reduction; and vector attraction reduction.
9.2.3.1 Pollutant Limits
Pollutant limits set the level for annual and cumulative pollutant loading rates of trace
elements for land application. The concentrations and analytes listed in the regulations will
likely change over time, with concentrations increasing or decreasing as more data is made
available. The analyte list is not expected to decrease, and the pollutant limits are not
expected to increase.
Some trace elements are essential to plant growth in small quantities while others have no
known beneficial function. Under certain conditions some trace elements can become
pollutants affecting plant growth, human or animal health, or environmental quality.
Regulation of trace elements is based on their behavior in the soil and their potential impacts.
The availability of trace elements for uptake by plants, and the potential for leaching to
ground water, is a function of soil binding affects. The more tightly trace elements are bound
to the soil, the lower the risk. In addition to soil binding, different species of plants take up
trace elements in varying amounts and may exclude other trace elements entirely.
Trace elements affect the food chain and environment in different ways. Some, like nickel
and zinc, are toxic to plants. Others, like cadmium, accumulate in plants at levels that are not
toxic to the plants but can be harmful to humans eating the plants. Selenium and
molybdenum may be toxic to animals in high quantities. Lead is not taken up by plants but
enters the food chain only when animals or humans directly eat biosolids.
Based on these differences in behavior, a risk assessment was developed by EPA to estimate
acceptable trace element loading rate limits for land application of biosolids. They evaluated
14 pathways for the transfer of trace elements from biosolids to plants, animals, humans, and
HDR ENGINEERING, INC.
CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000 PAGE 3
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the environment. For each pathway, EPA defined a "highly exposed individual as the person"
who would have the highest exposure to the biosolids applications. They then estimated the
highest application of each trace element that would have no effect on the highest exposed
individual in that pathway.
The loading limit for each trace element was based on the lowest limit estimated for any of
the pathways. The limiting pathways vary depending on the element. For some elements the
limiting pathway is toxicity to plants. For others it is toxicity to animals or humans eating
crops produced on the land, or toxicity to animals or humans directly eating biosolids.
Biosolids can either meet Exceptional Quality (EQ) or Ceiling Limits (CL) for concentrations
of trace elements as set forth in Table 9-1. If any of the concentrations of trace elements
exceed the Ceiling Limits, the biosolids are not suitable for land application and would be
regulated as a solid waste with disposal to a land fill.
Table 9-1. Trace Element Concentrations
Standard
Element Symbol Exceptional Quality Ceiling Limit
(mg/kg) (mg/kg)
Arsenic As 41 75
Cadmium Cd 39 85
Chromium Cr 1200 3000
Copper Cu 1500 4300
Lead Pb 300 840
Mercury Hg 17 57
Molybdenum Mo 18' 75
Nickel Ni 420 420
Selenium Se 36 362
Zinc Zn 2800 7500
1 Not listed in WAC 173-308. Limits shown are in 40 CFR 503
2. CL limit is 100 in 40 CFR 503
If any of the trace elements do not meet EQ limits, biosolids applications are limited by
annual or cumulative limits. Annual limits set the highest amount of any trace element that
can be applied in a single year. Cumulative limits specify the highest amount of any trace
element that can be applied to a land application site during its use as a land application site.
By meeting the EQ limits for trace elements, the land application regulations are minimized
along with the costs associated with compliance with these regulations. In some cases
compost vendors that process biosolids require EQ limits to be met for trace elements for any
matenal they process. By having biosolids that meet the EQ standards, more opportunities
are available for ultimate disposal.
9.2.3.2 Pathogen Reduction
Pathogen reduction regulation sets the minimum level of pathogen reduction that must be
• achieved to allow solids to be land applied, with and without land restrictions, or distributed
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BIOSOLIDS MANAGEMENT - October 6, 2000
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for home use. Pathogen reduction regulations classify biosolids in one of two classes. Class
A pathogen reduction is the most stringent, and the most difficult and expensive to meet.
Biosolids meeting these criteria must be essentially pathogen free. Criteria for Class B can be
met through several ways and are less stnngent than Class A. The drawback is that there are
land use restrictions that must be observed when only the Class B cnteria is met.
Methods to meet minimum levels of pathogen reduction (Class B) are as identified in Table 9-
2.
Table 9-2. Regulatory Definition of Processes to Significantly Reduce
Pathogens
Process
Description
Aerobic Digestion:
Air Drying:
Anaerobic Digestion:
Composting:
Lime Stabilization:
Other Methods:
The process is conducted by agitating biosolids with air or oxygen to maintain aerobic
conditions at residence times ranging from 60 days at 15°C to 40 days at 20°C. with a
volatile solids reduction of at least 38 percent.
Liquid biosolids are allowed to drain and/or dry on underdrained sand beds, or on paved
or unpaved basins in which the biosolids depth is a maximum of 9 inches. A minimum
of 3 months is needed, for 2 months of which temperatures average on a daily basis
above 0°C.
The process is conducted in the absence of air at residence times ranging from 60 days at
20°C to 15 days at 35°C to 55°C, with a volatile solids reduction of at least 38 percent.
Using the within -vessel, static aerated pile, or windrow composting methods, the solid
waste is maintained at minimum operating conditions of 40°C for 5 days. For 4 hours
during this period the temperature exceeds 55°C.
Sufficient lime is added to produce a pH of 12 after 2 hours of contact.
Other methods or operating conditions may be acceptable if pathogens and vector
attraction of the waste (volatile solids) are reduced to an extent equivalent to the
reduction achieved by any of the above methods.
If biosolids are to be applied to agricultural land, they must meet Class B requirements and
the following site restrictions apply.
➢ Food crops with harvested parts that touch the biosolids/soil mixture and are totally
above the land surface shall not be harvested for 14 months after application of
biosolids.
➢ Food crops with harvested parts below the surface of the land shall not be harvested
for 20 months after application of biosolids when the biosolids remain on the land
surface for four months or longer prior to incorporation into the soil.
➢ Food crops with harvested parts below the surface of the land shall not be harvested
for 38 months after application of biosolids when the biosolids remain on the land
surface for less that four months prior to incorporation into the soil.
➢ Food crops, feed crops, and fiber crops shall not be harvested for 30 days after
application of biosolids.
➢ Animals shall not be allowed to graze on the land for 30 days after application of
biosolids.
➢ Turf grown on land where biosolids are applied shall not be harvested for one year
after application when the harvested turf is placed on land with a high potential for
public exposure unless otherwise specified by the permitting authority.
➢ Public access to land with a high potential for public exposure shall be restncted for
one year after application of biosolids.
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BIOSOLIDS MANAGEMENT - October 6, 2000
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➢ Public access to land with a low potential for public exposure shall be restricted for 30
days after application of biosolids.
Additional methods to further reduce pathogens can be implemented to classify the biosolids
as Class A. Methods to meet Class A pathogen reduction are as identified in Table 9-3.
Table 9-3. Regulatory Definition of Processes to Further Reduce Pathogens
Process Description
Using the within -vessel composting method, the solid waste is maintained at operating conditions of
55°C or greater for 3 days. Using the static aerated pile composting method, the solid waste is
maintained at operating conditions of 55°C or greater for 3 days. Using the windrow composing method,
the solid waste attains a temperature of 55°C or greater for at least 15 days during the composting period.
Also, during the high temperature period, there will be a minimum of five turnings of the windrow.
Dewatered biosolids cake is dried by direct of indirect contact with hot gases, and moisture content is
reduced to 10 percent or lower Biosolids particles reach temperatures well in excess of 80°C, or the wet
bulb temperature of the gas stream in contact with the biosolids at the point where it leaves the dryer is in
excess of 80°C.
Liquid biosolids are heated to temperatures of 80°C for 30 minutes.
Liquid biosolids are agitated with air or oxygen to maintain aerobic conditions at residence times of 10
days at 55°C to 60°C, with a volatile solids reduction of at least 38 percent.
Biosolids are irradiated with beta rays from an accelerator at dosages of at least 1 0 megarad at room
temperature (20°C).
Biosolids are irradiated with gamma rays from certain isotopes, such as b0Cobalt and 137Cesium, at
dosages of at least 1 0 megarad at room temperature (20°C).
Biosolids are maintained for at least 30 minutes at a minimum temperature of 70°C.
Maintain pH above 12 for 72 hours, with temperature above 52°C for 12 hours. After 72 hours, at pH
above 12, biosolids are air-dried to greater than 50 percent total solids.
Other methods or operating conditions may be acceptable if pathogens are reduced to an extent
equivalent to the reduction achieved by any of the above add-on methods.
Composting:
Heat Drying:
Heat Treatment:
Thermophilic
Aerobic Digestion:
Beta Ray Irradiation:
Gamma Ray
Irradiation:
Pasteurization:
Lime Treatment
Other Methods:
9.2.3.3 Vector Attraction
Pathogens in biosolids pose a risk if there are routes for them to come in contact with humans
or animals. They are usually transmitted by a "vector" which is a living organism such as
insects, rodents, or birds which can 1) come into contact with biosolids and humans and
animals plus 2) transmit pathogens as a result of the contact.
Vector reduction is generally accomplished simultaneously with processes to reduce
pathogens and volatile solids. Digestion and composting destroy the organic carbon
compounds in raw sludge that serve as a food source for vectors. Lime stabilization and
drying further reduce vector attraction by creating environmental conditions (high pH or
dryness) unfavorable to vectors. Some vector attraction reduction processes (digestion,
composting) that destroy volatile organic solids also reduce odors after application. Volatile
organic solids are not destroyed by lime stabilization and drying. If lime stabilized or heat
dried biosolids are wetted, significant odors may result after application.
Table 9-4 lists 10 acceptable vector attraction alternates for biosolids. Alternates 1 to 8 for
digestion, lime stabilization, or drying processes are acceptable for biosolids applied at any
site, including lawns and home gardens. These 8 alternates meet the vector attraction
reduction requirements for EQ biosolids. Alternates 9 and 10 reduce vector attraction by
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CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000
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tilling or injecting biosolids into the soil at the land application site, but are not acceptable for
411 biosolids applied to lawns or home gardens.
•
•
Table 9-4. Vector Attraction Reduction Alternates
Alternate Number Description
1 Biosolids digestion processes with greater than 38 percent volatile solids reduction.
2. Test end -product of anaerobic digestion process. Forty day anaerobic test at 30-37°C. Acceptable
stabilization if less than 17 percent volatile solids reduction occurs during the test.
3 Test end -product of aerobic digestion process having less than 2 percent solids. Thirty day aerobic test at
20°C. Acceptable stabilization if less than 15 percent volatile solids reduction occurs during the test.
4. Facilities with aerobic digestion. Specific oxygen uptake rate (SOUR) test using end -product of
digestion process. Acceptable stabilization if uptake is less than 1.5 mg oxygen per g total solids per
hour at 20°C.
5 Facilities with aerobic digestion. Time/temperature requirement: Fourteen days residence time at
digestion temperatures greater than 40°C, with average digestion temperature greater than 45°C.
6. High pH stabilization. biosolids pH above 12 for 2 hours and greater than 11.5 for 24 hours.
7 Treatment by drying. Not to include unstabilized primary wastewater solids. Total solids content greater
than 75 percent before mixing with other material.
8 Treatment by drying. Can include unstabilized primary wastewater solids. Total solids greater than 90
percent before mixing with other materials.
9 Land application process. Injection into soil. No biosolids on soil surface 1 hour after application (Class
B) or 8 hours after application (Class A).
10 Land application process. Soil incorporation by tillage. Class A biosolids only Soil incorporation by
tillage within 6 hours of application.
9.2.4 Permits and Reporting Requirements
Prior to the adoption of WAC 173-308, land application permits for disposal of biosolids were
issued by the Yakima County Health Department and were valid for one year. With the
promulgation of WAC 173-308, permitting authority went to WDOE. Yakima County Health
Department (YHD) entered into a Memorandum of Understanding (MOU) with WDOE to
allow YHD oversight responsibility. YHD will inspect the application sites, approve
biosolids application rates, and monitor the various biosolids programs. Permitting authority
remains with WDOE.
There are two types of permits: general and site specific. A general permit is usually issued,
but a site specific permit can be requested when the general permit does not address practices
proposed. The Yakima Regional WWTP has both types of permits at this time.
Permits are good for five years and can be renewed. General permits allow for new sites to be
obtained throughout the permit life. Both WDOE and YHD collect fees. WDOE permit fees
are based on population equivalencies. The fee is adjusted annually based on growth
estimates as determined under 43.135 RCW. The WDOE biosolids permit fee for the Yakima
Regional WWTP for the period of July 1998 to June 1999 was $ 4,594.22 calculated at a rate
of $ 0.162 per residential equivalent (28,360 residential equivalents). The increase in the
permit fee over the previous year was $ 182.47 (1,126 residential equivalents). YHD permit
fees are based on the dry tons of biosolids applied during the year. The current rate per dry
ton is $ 1.45 with the 1999 permit fee calculated at approximately $ 2,175.00 (1500 dry tons).
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CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000
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Permitting of a land application site requires posting of informational signs on the site,
publishing a notice in the newspaper of the county where the biosolids will be applied, and
conducting an informational public meeting. The initial permit requires that a SEPA checklist
be completed.
9.3 Sludge Quantity and Quality
The Yakima Regional WWTP currently produces over 1,500 dry tons of biosolids (1,360
Metric tons) per year. Historically production has been fairly consistent as shown in Table 9-
5.
Table 9-5. Historical Biosolids Production
Year Dry Tons
1995 1542
1996 1549
1997 1523
Since the Yakima Regional WWTP is producing less than 1,500 metric tons (1,653 dry tons)
per year, they are required to monitor once per quarter or four times per year as shown in
Table 9-6. Once the production exceeds 1653 dry tons, monitoring frequency will increase to
six times per year. At the current time, the Yakima Regional WWTP has elected to monitor
biosolids 6 times per year.
• Table 9-6. Minimum Frequency of Monitoring - Land Application
Metric tons (U.S. tons) Frequency Per 365 -day period
•
Greater that zero but less than 290 (320)
Equal to or greater than 290 (320) but less that 1,500 (1,653)
Equal to or greater than 1,500 (1,653) but less than 15,000 (16,535)
Equal to or greater than 15,000 (16,535)
Once per year
Once per quarter (four times per year)
Once per 60 days (six times per year)
Once per month (12 times per year)
The samples are analyzed for nutrients as well as pollutant limits. With the nutrient data,
proper application rates can be determined which prevents adding too much nitrogen to the
soil. Table 9-7 shows current and historical average pollutant concentrations. These are
consistently below regulatory limits as listed in 40CFR 503 and WAC 173-308.
Table 9-7. YRWWTP Metal and Nutrient Average Concentrations (mg/kg) for 1995-1998
Year 1995 1996 1997 1998 40 CFR 503 /
WAC 173-308
Arsenic <MDL <MDL ND ND 41
Cadmium <RDL <RDL 3 71 3.37 39
Chromium 34.5 28.3 32.5 22.3 12006
Copper 800 794 701.2 442 1500
Lead 143 112 93 4 110 300
Mercury 3.27 3.74 0 91 ND 17
Molybdenum <RDL <RDL 10 6.7 18
Nickel <RDL <RDL 19.2 17.7 420
Selenium <MDL <MDL ND ND 1007
HDR ENGINEERING, INC.
CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000
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Table 9-7. YRWWTP Metal and Nutrient Average Concentrations (mg/kg) for 1995-1998
Year 1995 1996 1997 1998 40 CFR 503 /
WAC 173-308
Zinc 1,085 1,005 1,230 820 2,000
Nutrients
Organic N 40,318 44,220 48,197 49,521 N/A
AmmoniaN 6,865 13,310 6,247 4,144 N/A
NO2 / NO3 N N/A N/A 16.8 12.8 N/A
Phosphorus 7,170 15,588 15,899 17,122 N/A
Solids 23 75% 22.1% 20 7% 19.8% N/A
1. MDL — Minimum Detection Level.
2. RDL — Reliable Detection Level.
3. ND — Non Detect
4. N/A — Not Applicable
5 1998 data through August
6. Chromium deleted in 1995 from 40CFR 503
7. Selenium increased from 36 to 100 mg/kg in 1995 in 40CFR 503
The Yakima Regional WWTP laboratory staff currently analyzes biosolids and soil samples
for metal content. The nutrient analysis of the biosolids and the land application sites has
been completed by Cascade Analytical, Inc., Wenatchee, WA. Outside laboratory analysis for
soil and biosolids nutrients currently costs $ 5,000 annually.
The Yakima Regional WWTP produces Class B biosolids for pathogen reduction through
anaerobic digestion above 95 degrees Fahrenheit for a minimum of 15 days. They meet
vector attraction requirements by reducing volatile solids by a minimum of 38 percent through
anaerobic digestion. In 1997 and 1998, volatile solids reduction was approximately 57
percent. The biosolids currently meet EQ pollutant concentrations as shown in Table 9-7. The
annual reporting requirements are:
➢ Pollutant concentrations
➢ Description of how pathogen reduction is met
➢ Description of how management practices are met
➢ Description of how site restrictions for Class B biosolids are met
➢ Certification statements from both the generator and applicator that pathogen
requirements, vector attraction reduction requirements, management practices, and site
restrictions are met and determined under the supervisor's direction and supervision,
and that the supervisor is aware of penalties for false certification.
These records must be kept for 5 years and are intended to be self enforcing. Reports must be
filed annually with the above information to WDOE and EPA.
In addition to the annual production, there are still biosolids in the north and south lagoons
which need to be removed before any expansion can be made into the lagoon areas. The
north lagoon, though not in use, has approximately 1,000 dry tons of biosolids currently in
storage. The south lagoon currently has about 1,200 dry tons of biosolids in storage, with
another 80 dry tons added per year from centrifuge centrate loading. In total there is
HDR ENGINEERING, INC.
CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000
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approximately 2,200 dry tons of biosolids that must be removed from the lagoons as well as
II/ the estimated 1,500 dry tons generated annually.
•
•
The Yakima Regional WWTP is anticipated to continue to produce an Exceptional Quality
biosolid by practicing source control and plant process control. Source control strategies
include:
➢ Industrial pretreatment for removal of trace metals and organic compounds.
➢ Prevention of discharge of household hazardous waste through community awareness.
> Prevention of discharge of agricultural chemicals from truck washing facilities and
from individual households.
Operation control strategies at the Yakima Regional WWTP that should be continued to
produce a high quality biosolids include:
> Maximize screening of influent sewage to remove rags, debris, and plastics from the
wastewater.
➢ Maximize grit removal from the influent sewage.
➢ Maximize volatile solids and pathogen reduction in the anaerobic digestion process.
➢ Maximize grinding of raw sludge from the primary clarifiers to the anaerobic
digesters, and from the digesters to the dewatering process.
9.4 Biosolids Disposal Program
Federal and state regulations have recognized Biosolids as a quality soil conditioner. It is
considered to be rich in macronutnents such as nitrogen, phosphorus, and potassium, which
are necessary for crop growth. Biosolids also contain micronutrients such as zinc and copper
which plants also need. Biosolids do contain metals, not needed for crop growth, which may
pose a potential threat from bioaccumulation or leaching into groundwater. The Yakima
Regional WWTP biosolids are of Exceptional Quality and have low concentrations of metals
making them an acceptable by-product of wastewater treatment for re -use. There has been
some concern expressed by the agncultural community and by financial lending institutions
regarding the application of biosolids on land. In some cases, the food processing industry
has been unwilling to accept agricultural crops grown on soils where biosolids have been
applied.
9.4.1 Land Application Rates
Biosolids application rates are determined annually on a case by case basis for each site and
biosolids composition. Short term loading is usually limited by the nitrogen content in the
municipal biosolids. Long term loading tends to be limited by metals, as it is based upon
cumulative loads, which will limit the total number of applications a site can receive. The
biosolids produced at the Yakima Regional WWTP are of Exceptional Quality. It is estimated
that the current site life for the existing land application sites, based on trace elements
(metals), is over 100 years.
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CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000
PAGE 10
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The current process for biosolids application, once the permit is in place, is to apply the
biosolids at agronomic rates. These rates are driven by the calculated nitrogen requirements
for the specific crop. When biosolids are applied, only about 20 percent of nitrogen available
in the biosolids is in a useable form. The remainder must be mineralized into inorganic
nitrogen before it can be used. Organic nitrogen mineralizes at an approximate rate of 20
percent per year. With a residual present, less biosolids will need to be applied up to the point
in time where no nitrogen is needed for some years. In order to continue field rotation and
beneficial re -use, additional sites should to be considered to keep the program viable.
9.4.2 Permits
Prior to using biosolids on land, a permit must be obtained. The general permitting process
can start either with the farmer or the Yakima Regional WWTP. Once there is indicated
interest, WWTP staff will work with the farmer, YHD, and WDOE in obtaining the required
permit. Property location, site accessibility, and crop type are identified to determine if the
site meets state and federal regulations. Once approved, the soil and adjacent surface waters
will be analyzed and further surveyed. This more detailed survey looks at size, shape, slope,
and ability to limit access to this site, depth to groundwater, depth to bedrock, and soil
permeability. The soil samples are analyzed for pH, metals, nitrates, cation exchange
capacity, ammonia nitrogen, and total nitrogen. This information is used to prepare the
permit. Figure 9-1 shows the process followed to utilize biosolids on a land application site.
The WWTP staff will coordinate with the farm for delivery of biosolids as far as quantity and
time of year biosolids are needed. The WWTP staff delivers the biosolids while the farmer is
responsible for spreading and incorporation into the land. The WWTP staff and YHD will
verify spreading and incorporation of the biosolids is performed properly and in a timely
fashion. Since the Yakima Regional WWTP produces a Class B biosolids with regards to
pathogen reduction, restrictions per WAC 173-308 must be observed.
9.4.3 Existing Land Application Site
Biosolids have been applied at the Moxee site for approximately ten years. The Moxee site is
comprised primarily of several hop yards between 10 and 60 acres apiece. Factors affecting
the need for new biosolids site recruitment include:
➢ The hop yards comprising the Moxee site have received previous biosolids
applications and a soil nitrogen build-up has occurred. In some cases the test results
have not allowed further biosolids application. In other cases the nitrogen levels will
only allow minimal additional biosolids application.
➢ Regulations require soil sampling and testing of each individual hop yard intended for
application. This is time consuming and expensive, especially if the yards cannot be
applied to or will support only a small application.
➢ Individual yards often have different required application rates which complicates the
biosolids application process in the field.
➢ If a lagoon cleaning project is initiated, significant additional acreage will be required
for beneficial reuse.
HDR ENGINEERING, INC.
CITY OF YAKIMA
BIOSOIJDS MANAGEMENT - October 6, 2000 PAGE 11
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Collect Field Data
➢ Site Characteristics
> Soil test
➢ Cropping history
➢ Crop yield goal
Analyze Biosolids
> Nutrient content
> Contaminants
> Application method
Prediction/
Permitting
•
Determine Nutrient Needs
> Type of Crop
➢ Fertilizer guides
➢ Agronomist
•
Determine Biosolids
Application Rate
Land
Application
•
Measure Application Rate
Monitoring
Monitor Crop and Soil
> Plant tissue test
➢ Crop yield
➢ Soil residual nutnents
➢ Surface Water sampling
v
Adjust Future Applications
HDR ENGINEERING, INC.
CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000
Figure 9-1
Permitting and Monitoring
of Land Application Sites
PAGE 12
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A land application site with larger acreage would reduce soil sampling, monitonng, and
testing costs, and simplify the application process. New acreage, without previous biosolids
application, would be able to support high application rates, depending on existing soil
nitrogen levels.
Several factors should be considered in evaluating a potential biosolids site including:
➢ Distance from the wastewater plant directly effects hauling costs.
➢ The support of site neighbors for the biosolids program is a critical factor.
➢ The farmer and/or landowner should be active supporters of the beneficial utilization
of biosolids. The farmer must be willing to work through the regulatory burdens and
municipal oversight involved with a utilization site.
➢ Physical factors including soil conditions, slope, and surface water proximity all need
to be evaluated.
9.4.4 Natural Selections Farms As A Back Up Site
Natural Selections Farms (NSF) is a private operation in the lower Yakima Valley that has
been permitted by WDOE and the YHD as a beneficial reuse facility. They have close to
100,000 acres under permit for biosolids application. A large portion of the biosolids
generated in the Seattle area is trucked to NSF and land applied. The NSF acceptance fee is
currently $12/wet ton. Based on an estimated 1500 dry tons or 7500 wet tons of biosolids
produced annually at the Yakima Regional WWTP, the annual cost for disposal of biosolids at
the NSF site would be $90,000. The Yakima Regional WWTP would be responsible for
hauling expenses. The site is approximately 40 miles from the Yakima Regional WWTP. If
the time and expense associated with maintaining the Moxee site (approximately $18,000
currently) exceed $90,000 per year, the NSF site should be considered as the primary site for
disposal of biosolids.
In the summer of 1998, the WWTP staff altered the handling of dewatered biosolids. WWTP
staff have hauled dewatered biosolids directly to the application site instead of stockpiling
them on the paved biosolids storage area. In October 1998, a contract hauler was brought in
to haul stockpiled biosolids to the application site at a cost of $30,000. The contract hauler
moved approximately 1,000 dry tons during a one week period ($30/dry ton).
9.4.5 Biosolids Equipment
9.4.5.1 Front End Loader
A front end loader was purchased in 1994 to facilitate biosolids handling. In addition to
solids handling, it has been used for: roadway snow removal (wastewater and other
departments); loading, unloading, and moving equipment; clearing access routes; and
community service projects. It has also been used for composting, loading the truck for
hauling biosolids, and in the fall used at the biosolids application site to assist with biosolids
application. Loading the spreader trucks at the application site allows City Staff to monitor
the application process.
HDR ENGINEERING, INC.
CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000 PAGE 13
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9.4.5.2 Ford Semi Truck/Trailer
The Ford semi tractor was acquired in 1978. The truck and 20 cubic yard trailer require
extensive maintenance due to age and condition. The semi and trailer are generally used by
the Yakima Regional WWTP staff for hauling of dewatered biosolids from the centrifuge
load -out facilities to the paved biosolids storage area.
9.4.5.3 Peterbilt Semi Truck/Mate Trailer
The Peterbilt semi tractor and 30 cubic yard Mate trailer was acquired in 1995 and has
reduced the number of trips required to deliver the biosolids to the application site storage
areas. The semi and trailer is rated at 80,000 pound gross vehicle weight. The truck/trailer
combination is also used during the biosolids dewatering process when the 20 yard truck is
down for repairs or otherwise in use. To drive either of the semi trucks requires the operator
to have a combination driver's license with a Class A endorsement. The licensing
requirement limits the available pool of drivers for biosolids hauling. There are currently four
properly licensed drivers for the truck/trailer combination.
9.5 Biosolids Processing
Biosolids are generated through two processes: the primary treatment system for primary
sludge; and the activated sludge secondary treatment system for waste activated sludge
(WAS). Primary sludge consists of organic and inorganic materials which settle to the bottom
of the primary clarifiers. The primary clarifier mechanism sweeps the settled sludge to a
center hopper where air operated diaphragm pumps are activated to discharge the primary
sludge to the primary anaerobic digester. The second source, WAS, are biological solids
generated as a product of the secondary treatment process. Biological solids are removed
from the secondary clarifiers. A portion of the biological solids are returned to the aeration
basin (Return Activated Sludge -RAS) where they are mixed with incoming wastewater.
WAS is continuously removed from the activated sludge process with centrifugal pumps and
typically has a low solids content. WAS is pumped to and thickened in a dissolved air
floatation thickener (DAFT) before being sent to the primary digesters.
Only one DAFT is provided at the Yakima Regional WWTP. If this unit is taken out -of -
service for maintenance, waste activated sludge from the secondary clarifiers would be
discharged directly to the primary digesters. Unthickened WAS is at a very low solids
content and could impact digester hydraulic detention time. At the present time, with all the
primary digesters available, the inability to thicken WAS should not degrade digester
performance with short duration outages (24 to 48 hours). A combination of having digesters
out -of -service, and the loss of thickening capacity, may result in the inability to adequately
stabilize sludge.
Once in the pnmary digesters, the settled primary sludge and the thickened waste activated
sludge is mixed and heated in an anaerobic atmosphere. This process breaks down the
volatile solids into water, carbon dioxide, and methane. The methane provides fuel for the
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CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000
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DRAFT
plant boiler which heats the digesters and plant buildings. As more sludge is pumped into the
primary digesters solids overflow to the secondary digesters for storage prior to dewatering.
Pnor to 1998, when primary sludge and primary scum were pumped to the primary digester,
other light materials such as rags, plastics, and grease would also be pumped to the digester.
Rags and plastics represent an aesthetic problem in biosolids land application as the articles
are usually visible at the soil surface. To mitigate this problem, and provide a more uniform
material, grinders were added to the digester feed line, primary digester recirculation lines,
and centrifuge feed line during the last WWTP improvement project. Other changes that have
improved the quality of the biosolids include new bar screens, which remove material with a
diameter of -inch or greater before they are integrated into the biosolids.
Following digestion, the anaerobically treated biosolids are pumped from the secondary
digesters to the centrifuge to be dewatered. Two positive displacement feed pumps are
located in the basement of the Solids Building. The current policy at the Yakima Regional
WWTP is to dewater biosolids from the secondary digesters on a frequency that prevents
overflow to the lagoons.
To thicken biosolids in the centrifuge, polymer is added just prior to entering the centrifuge.
The polymer feed system at the Yakima Regional WWTP requires plant staff to mix dry
polymer with water in a batch process. Following the initial mix, and up to 2 hours of aging,
the polymer solution is transferred by pumping to a day -use feed tank. From the feed tank,
polymer is pumped at a rate of 8 to 10 gpm to the biosolids. Polymer usage is approximately
18 to 20 pounds per dry ton.
IIIIn 1991, the Yakima Regional WWTP installed a high capacity centrifuge for biosolids
dewatering in the solids building. The centrifuge has a hydraulic capacity of 270 gpm and can
produce a dewatered biosolids concentration of 22 to 25 percent. An existing centrifuge with
hydraulic capacity of 80 gpm was also refurbished. The low capacity centrifuge produces a
wetter dewatered biosolids concentration of 15 to 17 percent. If the high capacity centrifuge
is taken out -of -service for maintenance, the time required for dewatering increases from 30 to
35 hours a week to 75 to 90 hours a week (2.5 times). The wetter dewatered biosolids also are
undesirable from a handling and storage perspective. Liquids, or supernatant, from the
centrifuge process are discharged to the south lagoon located to the south of the activated
sludge basins while solids are conveyed to a load -out facility.
The lagoons at the Yakima Regional WWTP were originally constructed to store supernatant
from the secondary digesters. Supernatant is high in ammonia which would cause process
upsets if the supernatant were returned to the treatment plant influent. The lagoons also
provide a long-term off-line storage facility for sludge if one of the primary digesters had to
be taken out -of -service and insufficient capacity was available with the remaining primary
digesters on line.
•
The next WWTP improvement project will likely require the addition of at least one new
secondary clarifier. Past engineering reports have identified the east half of the existing north
lagoon as the most logical location for construction of this secondary clarifier. Expansion of
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CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000
PAGE 15
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DRAFT
the aeration basins may likely be placed in the area occupied by the west half of the existing
north lagoon.
Another potential project which may impact the use of the lagoons would be the utilization of
the south lagoon as a food processing storage lagoon dunng the portion of the fruit processing
season when the spray field is unable to accept hydraulic loading. An engineering report is
currently being prepared for completion in 2000 which may include a recommendation to
convert the south lagoon to a food processing storage facility.
The Yakima Regional WWTP may need some capacity storage to continue discharge of
centrifuge centrate which is high in ammonia concentration, and some emergency sludge
storage when digester cleaning is performed by the plant operations staff.
The solids load -out facilities consist of screw conveyors which transport the dewatered
biosolids from the centrifuge to a hopper either located inside the Solids Building at the north
end, or to a hopper located in the basement of the Solids Building at the south end. The
hoppers serve as wide spots in the dewatering process. From the hopper at the north end, a
screw conveyor discharges the dewatered biosolids to the exterior of the Solids Building on
the west side. The Yakima Regional WWTP semi truck and trailer equipment is generally
located under the hopper screw conveyor where biosolids are captured for transport to the
land application site.
From the hopper at the south end, a positive displacement pump discharges the dewatered
biosolids to a load -out station located on the exterior west side of the Solids Building. The
hopper on the south end is generally used only when the north end hopper and screw
conveyor system are out -of -service for maintenance.
Six acres were paved for biosolids storage and a 90 -foot truck scale was installed at the
Yakima Regional WWTP in 1993/1994. The paved biosolids storage area is located on the
west side of the lagoons and the east side of I-82. A landscaping berm and plantings were
constructed adjacent to I-82 to screen the paved biosolids storage area from public view.
A schematic of the Yakima Regional WWTP solids processing facilities is as shown in Figure
9-2. The solids balance numbers included on the figure are based on the average operating
data for 1997 through 1999 as set forth in Section 5.
Future solids quantities can be based on historical production records and consideration of
service area population growth, projected wastewater flows and loadings, and the operating
performance of the wastewater treatment facility. Projected values provide the basis for
determining sludge processing facility needs and off-site requirements for the vanous
utilization and/or disposal options.
In Section 3 of this report an analysis of the service area population growth was presented.
The service area includes the City of Yakima, the unincorporated area of West Valley,
Terrace Heights, and the City of Union Gap.
HDR ENGINEERING, INC.
CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000
PAGE 16
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11.3 mgd
19,500 lb/d BOD
17,800 Ib/d TSS
•
Septage
Figure 9-2 - Solids Balance Estimate (Average 94-98)
Grit
Basins
•
Screenings Grit to
To Disposal Disposal
Supernatant
Lagoons
Primary
Clarifiers
•
Primary Sludge
9,940 lb/d
Gas
Trickling
Filter
Aeration
Basins
Waste
Activated Sludge
/ 6,365 lb/d
6,170 lb/d
Dissolved
Air Flotation
Thickener
9,670 lb/d
Centrifuge
7,400 lb/d
Converted to Gas
HDR ENGINEERING, INC
CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000
4501b/d
Centrate
To Lagoons
9,2201b/d
Biosolids
To
Agricultural
Utilization
195 lb/day
To Plant
Headworks
Final
Clarifiers
Chlorine
Contact
1,500 Ib/d
\ Yakima River
PAGE 17
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9.6 Evaluation Process
A wide range of alternatives have been considered for expanding the Yakima Regional
WWTP solids treatment facilities to meet future capacity and effluent quality requirements.
This section describes the evaluation process used, identifies alternatives considered,
summarizes evaluation results, and provides recommendations for future wastewater
treatment modifications.
9.6.1 Define Process Methodology and Evaluation Criteria
To provide a consistent planning basis, HDR developed an evaluation methodology for the
wastewater facilities that was reviewed by City staff. This process defined evaluation criteria,
outlined the decision-making process, and prescribed cost estimating procedures. The
evaluation criteria are listed in Table 9-8. Except for cost, these critena were applied on a
non -weighted, qualitative basis.
Table 9-8. Evaluation Criteria
Technical Criteria Community/Environmental Criteria
> Proven performance — proven treatment > Air emission potential
process(es)
> Reliability — ability to consistently meet > Noise potential
permit
> Complexity > Aesthetic impact
> Flexibility — to accommodate changes in > Air quality
treatment requirements/growth/load
Operations & Maintenance Criteria ➢ Truck traffic
> Operator intensive — sensitive to operator Implementation Criteria
attention
> Maintenance intensive — major > Phasing — ability to match units with growth/need impacts
new/additional equipment
> Energy/chemical intensive — sensitivity to ➢ Ability to maintain operation during construction
increased costs
Cost Criteria ➢ Ease of construction
> Capital
> Operating
> Present Worth
9.6.2 Identify and Screen Ideas
Potential alternatives for expanding or improving the Yakima facility were identified by HDR
and reviewed by City staff. Following the initial alternatives development, an initial
screening step was conducted to eliminate ideas that were fatally flawed, technically
unproven, excessively expensive, or otherwise unworthy of detailed evaluation.
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
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9.6.3 Detailed Development and Evaluation
• Alternatives surviving the initial screening step were developed in detail. Facility sizing and
cost estimating were conducted for year 2020 and ultimate build -out design conditions.
Alternatives were compared based on cost and non -economic criteria. Based on this analysis,
preliminary recommendations for facility improvement alternatives are presented in Table 9-
10.
9.7 Alternatives Development and Screening
During the development of the alternatives for biosolids enhancement and the existing sludge
operations optimization, more than 30 ideas for improving or expanding the Yakima Regional
WWTP were identified. The project labeled each idea as "retain," "fail," or "feature." These
labels are defined as:
> Retain, In -Scope: Carry idea forward to detailed alternative analysis as part of this
facilities plan.
> Retain, Not -in -Scope: Valid idea, but outside the scope of this study. Address in
concurrent or future studies.
➢ Fail: Idea is fatally flawed. Do not carry forward to detailed alternative analysis.
> Feature: Idea should be considered as a component of other ideas generated, or as a
component of the predesign.
IIIA full listing of the ideas is presented in Table 9-9.
•
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
Page 19
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Idea
Table 9-9. Alternatives Evaluation
Initial Screening Result
Composting:
CO1
CO2
CO3
C04
Windrow Systems
Aerated Static Pile System
Non-aerated Static Pile System
In -Vessel Systems
Sludge Stabilization:
SSI Single -stage mesophilic anaerobic digestion
SS2 Two-stage mesophilic anaerobic digestion
SS3
SS4
SS5
SS6
SS7
Temperature -phased anaerobic digestion (TPAD)
Pre-pasteurization/mesophilic anaerobic digestion
Chemical treatment (lime stabilization)
High -rate mesophilic digestion
No digestion
Secondary Handling of Centrate:
RS1 Equalize centrate
RS2
RS3
Sidestream nitrification of centrate
Sidestream ammonia stripping of centrate
Biosolids Dewatering/Drying:
DW 1 Provide new 270 gpm centrifuge
DW2
DW3
Polymer.
PO1
P02
P03
PO4
Retain existing centrifuges and route flow to digesters for
storage in the event of an overflow
Belt filter press
Dry polymer feed and storage system
Liquid polymer feed and storage system
Polyblend DP series polymer feed system
Expand current polymer system tankage
Solids Handling Building:
SH1
SH2
SH3
SH4
SH5
SH6
SH7
SH8
Install vertical conveyor with the existing biosolids hopper
Install a new hopper next to the solids loadout facility with
a new conveyor system.
Retrofit the existing biosolids conveyor and hopper system
Expand the lab space
Add an enclosed solids loading bay
Enhance air emission control system
Build control room for noise control.
Purchase 30 cubic yard trailer (3 recom)
Retain for evaluation
Retain for evaluation
Retain for evaluation
Retain for evaluation
Retain — produces Class B biosolids.
Retain — does not have the ability to produce
Class A biosolids.
Retain — potential benefits regarding Class A
biosolids and dewatered cake dryness.
Retain — potential benefits regarding Class A
biosolids and dewatered cake dryness.
Retain — potential benefits regarding Class A
biosolids and dewatered cake dryness.
Fail — forecloses ability to produce Class B
biosolids at plant.
Fail — don't want to compost raw sludge
Retain for evaluation
Retain for evaluation — reduces nitrogen in
centrate stream
Fail — Increased complexity.
Retain for evaluation — existing redundant unit
is undersized at 80 gpm.
Fail — Provides short term solution.
Retain for evaluation
Retain for evaluation
Retain for evaluation
Retain for evaluation
Retain for evaluation
Retain for evaluation
Retain for evaluation
Retain for evaluation
Feature. Consider as option during pre -design
Feature. Consider as option during pre -design
Feature. Consider as option during pre -design
Feature. Consider as option during pre -design
Feature. Consider as option during pre -design
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
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• 9.8 Detailed Evaluation of Alternatives
•
•
Following the initial development and screening steps, the remaining alternatives were
developed in detail and compared against evaluation criteria. This section identifies the
alternatives evaluated, presents major design criteria used in development of the alternatives,
and describes the cost estimating methodology.
9.8.1 Summary of Alternatives Developed
Table 9-10 lists the alternatives considered for each process area. In a few instances, ideas
rejected during the initial screening step were to address specific issues raised by City staff.
Also, new ideas were introduced and evaluated during this phase of the study.
Table 9-10. Alternatives Subjected to Detailed Analysis
Idea Screening Result
Composting:
C01
CO2
CO3
C04
Windrow Systems
Aerated Static Pile System
Non-aerated Static Pile System
In -Vessel Systems
Sludge Stabilization.
SS 1 Single -stage mesophilic anaerobic digestion
SS2 Two-stage mesophilic anaerobic digestion
SS3 Temperature -phased anaerobic digestion (TPAD)
SS4 Pre-pasteurization/mesophilic anaerobic digestion
SS5 Chemical treatment (lime stabilization)
Secondary Handling of Centrate:
Equalize centrate
Sidestream return activated sludge (RAS) nitrification of
centrate
RS1
RS2
Biosolids Dewatering/Drying:
DW 1 Purchase new 270 gpm centrifuge
DW3 Purchase a belt filter press to operate in parallel with the
existing centrifuge.
Polymer.
P01
P02
P03
PO4
Dry polymer feed and storage system
Liquid polymer feed and storage system
Install Polyblend DP series polymer feed system
Expand current polymer system tankage
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
Retain for evaluation
Retain for evaluation
Retain for evaluation
Retain for evaluation
Retain for evaluation — produces Class
B biosolids.
Retain for evaluation — does not have
the ability to produce Class A biosolids.
Retain for evaluation — potential
benefits regarding Class A biosolids and
dewatered cake dryness.
Retain for evaluation — potential
benefits regarding Class A biosolids and
dewatered cake dryness.
Retain for evaluation — potential
benefits regarding Class A biosolids and
dewatered cake dryness.
Retain for evaluation
Retain for evaluation — will reduce
nitrogen in centrate stream.
Retain for evaluation — existing
redundant 80 gpm unit is undersized.
Retain for evaluation — existing
redundant 80 gpm unit is undersized.
Retain for evaluation
Retain for evaluation
Retain for evaluation
Retain for evaluation
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Table 9-10. Alternatives Subjected to Detailed Analysis
Idea Screening Result
Solids Handling Building:
SH 1 Install a vertical conveyor with the existing biosolids hopper Retain for evaluation
SH2 Retrofit the existing biosolids conveyor and hopper system Retain for evaluation
SH3 Install a new hopper next to the solids loadout facility with a Retain for evaluation
new conveyor system.
9.8.2 Design Criteria
An array of design criteria was established to guide development of the treatment alternatives
considered for the Yakima facility.
9.8.2.1 Planning Horizon
In most cases, alternatives were developed for two projected flow and loading conditions:
year 2020 and ultimate build -out. The 2020 scenario provided a near-term comparison of
economic, operational and implementation factors. The ultimate build -out provided a long-
term economic and non -economic comparison of the alternatives, and identified ultimate
facility requirements and space needs.
9.8.2.2 Process Sizing Criteria
The process sizing criteria are presented in Section 5 and 6. These criteria specify design
loading rates and operating parameters for critical unit treatment processes. Examples include
clarifier overflow rates, aeration basin mixed liquor concentrations, filter loading rates, and
chlorine contact basin detention times, etc.
9.8.2.3 Flows and Loadings
Initial development of alternatives was based on the maximum flow and loading condition
presented in Section 4. This condition was selected because it represents the worst-case
planning scenano for site space requirements. In most cases, the impact of using the most -
likely or minimum flow conditions was considered, at least qualitatively.
9.8.3 Development of Opinion of Probable Costs
The opinion of probable cost is an estimate for building facilities. 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 matenals 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.
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
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The sources of construction cost data are:
➢ Cost data for HDR designed WWTP expansion projects, adjusted to 2000 dollars.
➢ Recent construction costs for other, similar facilities, adjusted to regional market
conditions.
➢ Equipment pncing from manufacturers, with installation, structure, and housing costs
based on unit prices from recent HDR project designs.
All opinions of probable costs include allowances for site work, yard piping, electncal and
controls. Factors for allied costs were developed from recent construction projects. These
factors are presented in Table 9-11.
Table 9-11. Summary of 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%
For most treatment processes, the economic comparison of alternatives is strongly driven by
costs. Consequently, O&M costs were developed only where there was a substantial
difference in O&M requirements between the alternatives.
Individual O&M costs are based on comparable costs presently incurred by the Yakima
Regional WWTP. The labor rate for collection and treatment staff is estimated at $75,000 per
year. Plant employees are union members, and the plant is operated 7 days per week, 24
hours per day. Two thousand and eighty hours per year per full time employee, less ten and a
half weeks of benefit and training time, the total working hours per year per full time
employee is 1,660.
The current rate for power at the treatment plant (including demand charge impacts) is $0.053
per kilowatt-hour, and the rate for diesel fuel is approximately $1.09 per gallon.
9.9 Biosolids Enhancement Options
The Yakima Regional WWTP currently produces a Class B biosolids product which is
compatible with the current agricultural utilization program.
There has been discussion in the past concerning switching from Class B to Class A biosolids.
Class A biosolids do not have the regulatory burden of Class B. They can be given away or
sold to the public without land application restrictions. They have greater pathogen reduction,
and are more acceptable to the public.
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City of Yakima, WA
Biosolids Management- October 6, 2000
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DRAFT
Processes that could be added to produce Class A biosolids at the Yakima Regional WWTP
IIIinclude composting, chemical treatment, and added digestion.
•
•
9.9.1 Composting Alternatives
Composting of biosolids with a bulking agent/carbon source such as sawdust, wood chips or
chipped yard or green waste produces a product that takes on the physical characteristics of
the bulking agent/carbon source. With appropriate process control the composting process
can reliably produce a Class A biosolids product.
Composting is defined by EPA as "a method of solid waste treatment in which the organic
component of the solid waste stream is biologically decomposed under controlled aerobic
conditions to a state in which it can be easily and safely handled, stored and applied to land
without adversely affecting the environment." Composted biosolids are stable and can be
applied and stored relatively easily.
Composted biosolids produce a stable organic material that can be used as a soil conditioner.
The composting process is a natural aerobic microbiological decomposition of organic
compounds within the biosolids product.
The composting process is very susceptible to the moisture content of the biosolids/bulking
agent mixture. Successful systems require a low moisture content bulking agent. The
composting process can take from approximately 3 to 12 weeks, depending on the process.
The aerobic decomposition generates high temperatures which destroy pathogenic organisms.
The high temperatures also create the potential for foul air, a problem in many operating
systems.
Curing of the decomposing materials is the next step. This process takes approximately 30
days and serves to make the compost more marketable by furthering decomposition,
stabilization, pathogen reduction, and degassing. The compost may be stored from several
days to several months to allow drying.
The quality of the compost produced is a function of the characteristics of the biosolids and
bulking material. In general, the mass of the compost produced will be approximately three
times the initial incoming biosolids and half as dense.
Typical end users require the finished compost to have a comparatively uniform particle size
distribution. Although compost is a marketable commodity, its actual value is a function of
the marketplace. Generally, biosolids compost is of less quality than peat moss or mushroom
soil. To sell the biosolids compost product it has to be priced and marketed accordingly.
Three options were considered for the composting of the Yakima Regional WWTP biosolids:
windrow systems, static pile systems (aerated and not aerated), and in -vessel systems. A
description of each of these systems is provided below.
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Biosolids Management- October 6, 2000
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110 9.9.1.1 Windrow Systems
•
•
Following the mixing of biosolids and bulking agent, the material is placed in long rows.
These windrows are aerated by mechanical turning with a front end loader (or other similar
equipment) every day dunng the early stage of composting. This is required to satisfy the
high oxygen demand during early decomposition. After this initial stage the windrows are
typically turned three times a week for the next several weeks. The material is then stockpiled
and cured. The major disadvantage in windrow composting is the possibility of
reintroduction of pathogenic microorganism. Material from the outside of the windrows is
constantly pushed to the inside during turning.
9.9.1.2 Static Pile Systems
There are two approaches to static pile composting; aerated and non-aerated. While windrow
systems require constant turning to maintain aerobic conditions, an aerated static pile receives
its air through a forced air system of perforated pipes underneath the composting bed that
draws air from the outside, through the pile into the piped system. These pipes are covered
with wood chips or another bulking material to facilitate uniform aeration. The composting
material is placed on top of this bed and covered with screened or finished compost to serve
as insulation. The non-aerated static pile technique relies on a well -mixed porous pile of
compost, which is aerated by natural convection. This method requires substantially longer
curing times but also requires significantly less equipment and labor to operate. Static pile
systems require less space, are less manpower and equipment intensive than the windrow
systems, and are not as subject to reintroduction of pathogen organisms.
9.9.1.3 In -Vessel Systems
The configuration of in -vessel composting systems can vary widely (circular, rectangular
towers, boxes, bins, etc.). Composting with the in -vessel system is similar to the two open
aeration systems just described. In -vessel systems can produce a final product in less time.
These systems have the potential advantage of controlling composting foul air inherent in its
enclosed arrangement. In -vessel systems are typically more capital- and maintenance -
intensive.
9.9.2 Yakima Regional Experience in Composting
Windrow Composting was tested by the Yakima Regional WWTP from 1993 to 1997. Initial
tnals produced a Class A biosolid when mixed with chipped yard waste. In 1995, grass
harvested from the Industrial Spray Field was added to the mixture. The biosolids produced
were used to improve the spray field soil, and on the agricultural museum wheat field in
Union Gap.
In 1996, In -vessel Composting was tested with the guidance of Green Mountain
Technologies. To control air emissions, the system used a biofilter of mature compost and
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Biosolids Management- October 6, 2000
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wood chips to absorb and break down the foul air. The in -vessel compost system consisted of
a mixer, container, and computer operated blower. The mixer blended the compost which
was then placed in the container. Attached to the container was the computer operated
blower. The computer used a temperature probe to monitor the composting and operate the
blower. Four different mixes were tned with variable results. Mixes with grass tended to dry
out and not deteriorate. Foul air containment was successful using the biofilter.
In -vessel Composting was tried again in 1997 using composting bags attached to a blower.
The mix consisted of biosolids and chipped yard waste. Once mixed, it was placed in large
(bag 1 was 250 feet long, bag 2 was 190 feet) plastic bags with adjustable vents. The compost
remained in the bags for three months. The bags were cut open and the compost removed and
incorporated into the spray field soil. The system was successful in producing Class A
biosolids and containing foul air.
9.9.3 Chemical Treatment Alternative
Alkaline chemicals can be mixed with sludge or Class B biosolids to produce a Class A
product. The pathogen kill is accomplished by a combination of high pH and heat. Typical
alkaline products are lime, or a combination of lime and kiln byproducts.
Lime stabilization is practiced in many communities, some on raw sludge and some on
digested biosolids. A number of commercial operators that use the lime/kiln product
derivative mix have developed land utilization biosolids programs for municipalities.
9.9.4 Alternatives Evaluation
➢ In -vessel composting systems produce a more consistent compost product and reduce
the compost time from months to weeks. They are normally found in more densely
populated areas where there is a potential for complaint of foul air and the land is
expensive.
> Static pile and windrow systems have a potential to generate complaints from foul air
and require large amounts of land area. They are typically found away from urban
areas where it is sparsely populated and the land is inexpensive.
➢ The use of alkaline based chemicals with the current Class B sludge product would
provide a low capital cost option to respond to a sudden change in regulations that
required a Class A product.
➢ The sudden increase in pH results in the release of ammonia and other odorous gases.
This would require foul air treatment, or relocation of biosolids treatment to an off-site
location. It is uncertain whether lime treatment would be acceptable, as soils in the
area already tend to be alkaline. The alkaline chemical addition produces a friable
product, changing its visual character to a gray, sandy type product.
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
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9.9.5 Preliminary Recommendations
• While there are clear advantages to producing Class A biosolids, it has not been shown to be a
cost effective solution for the Yakima Regional WWTP. There is also no demonstrated desire
for a Class A product in the Yakima Region. Class B biosolids are accepted by the local
farming community but application is currently limited to agricultural sites in remote areas
and on lands where contact with the agricultural crop will not occur.
•
•
9.9.6 Sludge Enhancement Alternative Cost Estimates
Table 9-12 identifies the estimated capital costs for the sludge enhancement alternatives.
Table 9-12. Opinion of Probable Costs for Biosolids Enhancement Alternatives
Alternative Unit Cost ($/dry ton of biosolids)' Comment
Composting
Windrow Systems
Aerated Static Pile System
Non-aerated Static Pile System
In -Vessel Systems
Chemical Treatment (Lime Stabilization)
250-350
350-450
275-375
3254252
400-600
At remote site
At remote site
At remote site
Does not include vessel construction
At remote site
1. Excludes digestion/dewatering costs.
2. Variation between in -vessel and windrow systems depends on the land acquisition costs and proximity to populated
areas.
9.10 Added Digestion
Two possible methods of digestion which could be added at the Yakima Regional WWTP to
produce a Class A biosolid include temperature -phased anaerobic digestion (TPAD) and pre -
pasteurization followed by the current mesophilic anaerobic digestion. Two other processes
that are presented, single -stage mesophilic anaerobic digestion, and two-stage mesophilic
anaerobic digestion, produce Class B biosolids.
Anaerobic digestion is a two-stage process, typically operated at elevated temperatures. The
phase and temperature selection determines process performance. Several types of bactena
are involved in anaerobic digestion. The key ones are as follows:
➢ Acid-forming bacteria convert complex organic compounds to produce volatile fatty
acids (VFAs), pnmarily acetic and propionic acid. These organisms are relatively fast
growing, requinng a solids retention time on the order of 1 to 2 days. When grown by
themselves, the acid end product will reduce the pH. These organisms can sustain
growth under low pH (less than 4) conditions.
➢ Methane -forming bacteria convert VFAs to methane and carbon dioxide. The
methane formers are slow-growing organisms and require a sludge age exceeding 5
days (typically designed for at least 10 days). These organisms are pH sensitive,
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preferring a neutral pH environment. More importantly, low pH will reduce the
bacterial activity and could cause digester failure (termination of methane production).
➢ A third set of organisms (hydrogen -producing and hydrogen -consuming organisms)
also are present, but their role in optimizing full-scale digesters has not been
established.
Considerable research has been conducted into the benefits of separating and combining the
two digestion stages. Traditionally, the two stages have been combined by having one large
digestion stage for both acid and methane formation. By separating the digestion process into
its main stages (acid and methane formation) the operation of each stage can be optimized.
Stage one can be designed to optimize acid formation, utilizing a shorter HRT and operating
at low pH. The second stage can be operated to produce methane.
The performance of anaerobic processes increases with higher temperature. Research has
shown that the process has two optimal temperature ranges—the mesophilic range at around
95-98 degrees Fahrenheit and the thermophilic range around 130-135 degrees Fahrenheit.
Mesophilic digestion has traditionally been considered less efficient but more stable than
thermophilic digestion.
Even though the higher temperatures provide (theoretically) a more efficient treatment
process, the process has practical limitations. The higher operating temperatures require
larger heat exchangers to heat incoming sludge and maintain thermophilic conditions. Heat
loss from the reactor increases, requiring additional heating and higher operating costs. Some
reports on thermophilic digestion indicated problems with foaming and foul air. These
problems have made thermophilic digestion unattractive.
Recent developments of the 503 regulations have required a new look at phase separation and
thermophilic digestion, which provide a significant increase in pathogen destruction,
producing a Class A product.
➢ By creating several stages in the digestion process, the reactor configuration
eliminates short circuiting, and the pathogen destruction kinetics improve significantly
reducing pathogen densities. When splitting the digester into several stages, the
minimum sludge age for methanogenic bacteria must be maintained. This means that
effective digestion can be achieved in two or three reactors in series, provided that at
least one reactor maintains the minimum 10 day HRT required for methane former
growth.
➢ Increasing the operating temperature significantly increases pathogen destruction.
Thermophilic digestion is superior to mesophilic digestion in terms of pathogen
destruction. Several utilities operate digesters in the thermophilic range and have
demonstrated the ability to meet Class A sludge pathogen levels.
Several other methods for producing Class A biosolids are available to the Yakima Regional
WWTP including heat drying and irradiation. Many of these alternatives were described in
the 1993 Biosolids Management Plan.
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City of Yakima, WA
Biosolids Management- October 6, 2000
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• 9.10.1
9.10.1.1
•
•
Alternatives Considered
Single -Stage Mesophilic Anaerobic Digestion
Single -stage mesophilic anaerobic digestion uses a single -stage reactor operated at a hydraulic
retention time of at least 15 to 20 days at mesophilic temperatures (95-98 degrees Fahrenheit).
This process produces a Class B sludge. Table 9-13 identifies generally recognized design
criteria for mesophilic anaerobic digestion.
Table 9-13. Design Criteria for Single -Stage Mesophilic Anaerobic Digestion
Parameter Value Units
HRT — maximum month 20 days
HRT — maximum week 15 days
HRT — average; one out of service 15 days
Temperature 95 Deg F
Single stage mesophilic anaerobic digestion is the process used for reduction of solids at the
Yakima Regional WWTP.
Production capacity for processing of solids will be limited in one of two areas: primary
digester capacity, or biosolids dewatering capacity. The Yakima Regional WWTP currently
has one large primary digester (PD -1) and two small primary digesters (PD -2 & PD -3). The
small digesters are each capable of handling roughly one-third the flow of the large one.
Based on current loading rates as shown in Table 9-14, if all the digesters are operational,
detention time is nearly 40 days at average annual conditions. If PD -1 is not operational, and
PD -2 and PD -3 are in service, detention times during maximum month conditions currently
approach minimum detention times required (15 days).
Table 9-14. Effects of Digester Capacity versus Detention Time
Flow (GPD) PD -1,2, & 3 PD -1 & 2 or 3 PD -2 & 3
41,407 1 39.8 31 17.5
48,617 2 33.9 26.4 14 9
1 1997 Average flow
2. Maximum monthly flow (Dec. 97)
Organic loading rates are considered in digester operations. Volatile solids must be reduced
to meet regulatory requirements. An efficient well mixed digester will typically operate with
an organic loading rate between 0.1 and 0.4 Ib VS/ ft3/ day. Actual loading rates from 1997
range from 0.055 to 0.16 lb VS/ ft3/ day. The actual loading rate is well within organic
loading rate limits and is not considered to be a limiting factor to digester capacity at the
Yakima Regional WWTP.
Although current digester capacity appears to be adequate for current conditions, as the
service area flow and loadings increase, additional digester capacity will be needed. Table 9 -
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Biosolids Management- October 6, 2000
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15 identifies the anticipated solids loading to the primary digester for current, the year 2020,
and buildout conditions.
ble 9-15 Projected Solids Loading for the Yakima Facility
Parameter
1999
2020
Buildout
Avg Flow (gpm)
30.3
47.0
59.0
Avg Flow (gpd)
43,630
67,680
84,960
Avg Solids (ppd)
9,670
14,980
18,750
Max Mo Flow (gpm)
35 0
54.3
68.5
Max Mo Flow (gpd)
50,400
78,200
98,640
Max Mo Solids (ppd)
18,610
29,030
36,250
Based on a current digester volume of 220,000 cubic feet or 1,645,600 gallons, the existing
digesters can maintain a minimum 20 -day detention time (with all digesters in service) until
the maximum month flow to the digesters reaches 82,280 gpd (or after 2020). As noted
above, with primary digester (PD -1) out of service, the two remaining smaller primary
digesters (PD -2 and PD -3) are approaching the minimum detention time required at a flow to
the digesters of 48,300 gpd (15 days detention time).
To provide adequate system redundancy, one new single stage mesophilic anaerobic digester
should be constructed prior to 2020. The new digester would be similar to PD -1 with a 70
foot diameter and 32 foot sidewater depth (920,300 gallons). Table 9-16 provides an opinion
of probable cost for a new single stage mesophilic anaerobic digester.
Unit
Table 9-16. Opinion of Probable
Cost for Single -Stage Mesophilic Digester
Opinion of Probable Cost
Anaerobic Digester/Ancillary
Electrical (15%)
UC (7%)
Sitework and Yard Piping (20%)
Subtotal Anaerobic Digester
Contractor overhead and profits (15%)
Subtotal
Contingency (20%)
Subtotal
Sales tax (8%)
Subtotal
Engineering, legal and fiscal (25%)
Total Opinion of Probable Cost
$1,512,200
$226,800
$105,800
$302,400
$2,147,200
$322,000
$2,469,200
$293,800
$2,963,000
$237,000
$3,200,000
$800,000
$4,000,000
With the additional single stage mesophilic anaerobic digester, the Yakima Regional WWTP
would have sufficient digester capacity to meet buildout design conditions even with the new
digester, or the existing primary digester (PD -1), out of service (minimum 15 -day detention
time). With all digesters in service, the detention time in the digesters in 2020 would be 32
days during maximum month average daily flow conditions, and at buildout would be 28 days
during maximum month average daily flow conditions.
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City of Yakima, WA
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9.10.1.2 Two -Stage Mesophilic Anaerobic Digestion
In two-stage (phase -separated) digestion, the acid and methane production phases are
separated into two reactors. The acid phase requires a 2 to 3 day hydraulic retention time
(HRT) under mesophilic operation. The methanogenic phase is designed with an extended
HRT to provide sufficient time for biological growth and stabilization of the process. This
process produces a Class B biosolids. Table 9-17 summarizes the design criteria for this
option.
Table 9-17. Design Criteria for Two -Stage Mesophilic Anaerobic Digestion
Parameter Phase 1 Phase 2 Units
HRT — maximum month 3 15 days
HRT — maximum week 2.5 10 days
HRT — average; one out of service 2.5 10 days
Temperature 95 95 Deg F
Two stage mesophilic anaerobic digestion should be considered if an increase in digestion
capacity is required at the Yakima Regional WWTP. New acid phase digesters would be built
at the existing complex rather than one large single stage mesophilic anaerobic digester.
With two stage mesophilic digestion, the existing primary digester detention time for
maximum month average daily conditions is reduced from 20 days to 15 days. With one
digester out of service, the detention time in the remaining digesters can be reduced from 15
days to 10 days. If primary digester PD -1 were out of service, the flow rate to the smaller
ID pnmary digesters (PD -2 and PD -3) would increase from 48,300 gpd to 72,500 gpd at the 10
day detention time. This flow rate is higher than the average daily flow rate (67,680 gpd) to
the digesters in 2020, but is less than the anticipated maximum month average daily flow rate
(78,200 gpd) in 2020. The two stage mesophilic digestion process would require two new
acid phase digesters. Each acid phase digester would be 35 -foot in diameter and 32.5 -foot
sidewater depth (233,700 gallons. Table 9-18 provides an opinion of probable cost for two
new acid phase mesophilic anaerobic digesters.
Table 9-18 Opinion of Probable Cost for Two Acid Phase Mesophilic Digesters
Unit Opinion of Probable Cost
Acid Phase Digesters/Ancillary $1,125,000
Electrical (15%) $168,800
UC (7%) $78,800
Sitework and Yard Piping (20%) $225,000
Subtotal Acid Phase Digesters $1,597,600
Contractor overhead and profit (15%) $239,600
Subtotal $1,837,200
Contingency (20%) $367,400
Subtotal $2,204,600
Sales tax (8%) $176,400
Subtotal $2,381,000
Engineering, legal and fiscal (25%) $595,300
Total Opinion of Probable Cost $2,976,300
•
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The two new acid phase mesophilic digesters would be constructed with sufficient capacity to
provide 3 days detention time during annual average flow design for buildout conditions
(77,470 gpd x 3) for each digester, or 2.6 days detention time during maximum month
average flow design for buildout conditions (89,570 gpd x 3). For 2020 design conditions, the
detention time for annual average flow design (67,680 gpd) would be 3.5 days, and for
maximum month average flow design for 2020 conditions (78,200 gpd) would be 3 days.
With two acid phase mesophilic digesters, the City would have complete redundancy for the
acid phase process.
As noted above, with primary digester PD -1 out of service, flow rate to primary digesters PD -
2 and PD -3 would be limited to 72,500 gpd to maintain 10 days detention time in the
methanogenic phase. If digester PD -1 was out of service however, it would be possible to
utilize the redundant acid phase mesophilic digester in the methanogenic phase to increase
overall detention time. By adding an additional 233,700 gallons to the methanogenic phase,
the detention time for maximum month average flow design for buildout conditions (89,570
gpd) would be 10.7 days. With all digesters in service except for the redundant acid phase
mesophilic digester, the detention time in the existing primary digesters in 2020 would be 21
days during maximum month average daily flow conditions, and at buildout would be 18 days
dunng maximum month average daily flow conditions.
9.10.1.3 Temperature -Phased Anaerobic Digestion
This option utilizes temperature -phased anaerobic digestion (TPAD). The acid phase requires
a 1-2 day HRT under thermophilic operation. The methanogenic phase is designed with an
extended HRT to provide sufficient time for biological growth and stabilization of the
process. A new -acid phase digester would be built at the existing complex. Due to the high
temperatures in the first stage, the heating requirements for the methanogenic stage are likely
to be minimal. Table 9-19 summarizes the design criteria for this option.
Table 9-19. Design Criteria for Two -Stage Thermophilic/Mesophilic Anaerobic
Digestion
Parameter Phase 1 Phase 2 Units
HRT — maximum month 2 15 days
HRT — maximum week 2 10 days
HRT — average; one out of service 1 10 days
Temperature 131 95 Deg F
TPAD is considered as innovative technology and will result in a Class A biosolids. The
phase and temperature separation provides separate biological growth and pathogen
inactivation control. The process is relatively complex compared to the current mesophilic
digestion. A balance between the acid and methane phase of digestion will need to be
maintained. Additional process control will be needed with the selection of acid stage
treatment in maintaining operating temperatures. Increased temperatures may require
additional heat exchangers with increased methane gas usage and increased maintenance.
HDR Engineering, Inc
City of Yakima, WA
Biosolids Management- October 6, 2000
Page 32
•
•
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DRAFT
The major differences between TPAD and the acid phase mesophilic digestion described
previously is the reduction of the acid phase digester tankage from 233,700 gallons to 160,500
gallons, and the increase in operating temperature of the new digesters from 98 Deg F to 135
Deg F. As with the acid phase mesophilic digestion, the detention time in the existing
digesters for maximum month average daily conditions is reduced from 20 days to 15 days.
With one digester out of service, the detention time in the remaining digesters can be reduced
from 15 days to 10 days.
The new TPAD process would require two new acid phase digesters. Each acid phase
digester would be 29 foot in diameter and 32.5 -foot sidewater depth (160,500 gallons). Table
9-20 provides an opinion of probable cost for two new acid phase TPAD digesters. Although
the cost of the concrete tankage would be less than those for the acid phase mesophilic
digesters, additional insulation and larger heat exchangers are anticipated to increase initial
costs.
Table 9-20. Opinion of Probable Cost for Two TPAD Digesters
Unit Opinion of Probable Cost
TPAD Phase Digesters/Ancillary $1,315,000
Electrical (15%) $197,300
UC (7%) $92,100
Sitework and Yard Piping (20%) $263,000
Subtotal TPAD Phase Digesters $1,867,400
Contractor overhead and profit (15%) $280,100
Subtotal $2,147,500
Contingency (20%) $429,500
Subtotal $2,577,000
Sales tax (8%) $206,200
Subtotal $2,783,200
Engineering, legal and fiscal (25%) $695,800
Total Opinion of Probable Cost $3,479,000
Each new TPAD digester would be constructed with sufficient capacity to provide 2 days
detention time dunng maximum month average flow design for 2020 conditions (78,200 gpd).
This capacity would also be sufficient to provide 2 days detention time during annual average
flow design for buildout conditions (77,470 gpd). For maximum month average flow design
for buildout conditions (89,570 gpd), the detention time in the TPAD digester would be 1.8
days.
If primary digester PD -1 were out of service, as with the acid phase mesophilic digester
process, the second TPAD phase digester could be used to increase total detention time in the
methanogenic phase. By adding an additional 160,500 gallons to the methanogenic phase, the
detention time for maximum month average flow design for buildout conditions (89,750 gpd)
would be 9.9 days, or slightly less than the 10 days recommended for TPAD process. This
slight reduction in detention time is considered to be acceptable based on anticipated risk
associated with failure of primary digester PD -1 during maximum month design conditions.
With all digesters in service, except for the redundant TPAD phase digester, the detention
time in the existing primary digesters in 2020 would be 21 days during maximum month
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
Page 33
DRAFT
average daily flow conditions, and at buildout would be 18 days dunng maximum month
• average daily flow conditions.
•
•
9.10.1.4 Pre-Pasteurization/Mesophilic Anaerobic Digestion
Pre -pasteurization at 158 degrees Fahrenheit for 30 minutes will meet the 503 regulatory
requirements for Class A biosolids. The facilities required under this option are identical to
those in single -stage mesophilic digestion, except that a pasteurization unit is added to treat
incoming sludge. Pre -pasteurization raises the incoming sludge temperature and reduces the
heating requirements for the digester itself. Table 9-21 summarizes the design criteria for this
option.
Table 9-21. Design Criteria for Pre -Pasteurization and Mesophilic Anaerobic
Digestion
Parameter Pasteurization Digestion Units
HRT — maximum month 30 min 20 days
HRT — maximum week 30 min 15 days
HRT — average; one out of service 30 min 15 days
Temperature 158 95 Deg F
Pre -pasteurization is an established technology but not commonly used. It requires special
consideration for heat exchangers to maintain the high temperatures. Pre -pasteurization is a
more complex process than mesophilic digestion and requires attention to control the
pasteurization process. The process is considered to be maintenance intensive with little
flexibility in digester operation.
The pre -pasteurization process will provide Class A biosolids, but does not add digester
capacity. If pre -pasteurization is selected, the single stage mesophilic anaerobic digester
described previously would also be needed. Table 9-22 provides for an opinion of probable
cost for two new pre -pasteurization tanks preceding the mesophilic digestion process. Each
pre -pasteurization tank would be 8 -foot in diameter and 9 -foot sidewater depth (3380 gallons)
based on an anticipated maximum day flow rate at buildout of 100 gpm.
Table 9-22. Opinion of Probable Cost for Pre -Pasteurization Tankage
Unit Opinion of Probable Cost
Pre-Pasteurization/Ancillary $380,000
Electrical (15%) $57,000
UC (7%) $26,600
Sitework and Yard Piping (20%) $76,000
Subtotal Pre -Pasteurization Tankage $539,600
Contractor overhead and profit (15%) $80,900
Subtotal $620,500
Contingency (20%) $124,100
Subtotal $744,600
Sales tax (8%) $59,600
Subtotal $804,200
Engineering, legal and fiscal (25%) $201,100
Total Pre -Pasteurization Tankage $1,005,300
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
Page 34
•
•
•
DRAFT
With the addition of the single stage mesophilic digester for increased detention time, the total
opinion of probable cost for pre-pasteunzation and mesophilic digestion would be
$5,005,300.
9.10.2 Alternatives Evaluation
➢ Single -stage mesophilic anaerobic digestion is an attractive option for producing Class
B biosolids since it is the existing process at the Yakima Regional WWTP and
requires less retrofits than two-stage mesophilic anaerobic digestion.
➢ Two-stage mesophilic anaerobic digestion will provide a Class B biosolids, and will
also provide sufficient digester capacity to meet maximum month average daily flow
design conditions for buildout with the largest primary digester (PD -1) out of service.
> Producing Class A biosolids with temperature -phased digestion will be beneficial if a
market for the Class A biosolids product develops or local utilization of Class B
biosolids can not be maintained. The temperature -phased digestion will require
additional operator attention than either single -stage mesophilic anaerobic digestion or
two-stage mesophilic anaerobic digestion.
> Pre-pasteunzation/mesophilic anaerobic digestion can provide Class A biosolids, but
would not provide added digester capacity to meet required detention times with the
largest primary digester (PD -1) out of service.
9.10.3 Recommendations
This report recommends that the decision on selection of a preferred alternative be postponed
until the next update of the Wastewater Facilities Plan. The opinion of probable cost for the
single -stage mesophilic anaerobic digester should be included in financial planning for this
improvement at a future date.
9.11 Existing Facilities Needs
During the treatment plant review session with operations personnel and wastewater division
staff, needed facility improvements were identified that should be included as key features in
future plant upgrade projects. These improvements include:
9.11.1 Solids Handling Building
> Double the lab area in order to secure additional space for sampling and other related
activities.
➢ Construct an enclosed solids loading structure attached to the existing solids handling
building.
> Upgrade the existing air emission control system to provide enhanced ventilation and
air emission control in the Solids Handling Building.
> Build a separate control room that allows observation of centrifuge operation while
providing noise control.
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
Page 35
•
•
•
DRAFT
➢ Purchase additional 30 cubic yard biosolids semi and trailers for biosolids hauling.
Opinion of probable costs for these features are presented in Table 9-23.
Table 9-23. Opinion of Probable Cost for the Solids Handling Building
Unit Opinion of Probable Cost
Solids handling building retrofits
Additional Lab Space $96,000
Ventilation $30,000
Solids loading bay $699,000
Separate Control Room $50,000
Subtotal building retrofits $875,000
Electrical (15%) $131,300
I/C (7%) $61,300
Sitework and Yard Piping (20%) $175,000
Subtotal Capital Construction Costs $1,242,600
Contractor overhead and profit (15%) $186,400
Subtotal $1,429,000
Contingency (20%) $285,800
Subtotal $1,714,800
Sales tax (8%) $137,200
Subtotal $1,852,000
Engineering, legal and fiscal (25%) $463,000
Total Opinion Probable Cost $2,315,000
1 Opinion of probable cost for the addition of a solids loading bay 32 feet wide by 87 feet long by 21 feet tall at $200 per
square foot. Includes lighting, 12' by 18' rolling door, insulation and thermal protection. If the building were 31 feet
tall to allow for installation of the centrifuges above the loading bays the building cost would be $799,000
9.12 Secondary Handling of Centrate Alternatives
Centrate stream management options may be used to equalize loadings to the liquid stream
processes, to direct recycle flows to the optimal location within the treatment process and to
resolve bottlenecks. Handling of centrate from the dewatering process is currently directed to
the south storage lagoon.
9.12.1 Alternatives Considered
Management options for reducing the impact of centrate stream ammonia loads on the
activated sludge process are equalization and biological treatment. Delivery of flows to the
aeration basins for either alternative should be separated into each individual aeration basin.
Equalization would provide a 24-hour detention time for the centrate stream under build -out
peak flow conditions of 450 gpm. Using the peaking factors developed in section 4 a storage
volume of 650,000 gallons at build -out conditions would be required.
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
Page 36
•
•
DRAFT
Sidestream biological treatment would use the return activated sludge stream to nitrify the
centrate. This approach requires a new aerobic reactor and associated air supply and pumping
facilities. At build -out conditions with a flow of 450 gpm, a reactor volume of 770,000
gallons would be necessary.
9.12.2 Alternatives Evaluation
➢ Equalization of the centrate stream can reduce the ammonia nitrogen load on the
nitrification process and requires a minimum storage volume.
➢ Biological centrate treatment is feasible and requires a separate treatment process.
The opinion of probable costs of the centrate treatment alternatives without cost factors are
presented in Table 9-24.
Table 9-24. Opinion of Probable Cost for Centrate Treatment Alternatives
Unit Opinion of Probable Cost
Biological treatment
Basin construction
Basin aeration/Piping
Pumping equipment
Electrical (15%)
1/C (7%)
Sitework and Yard Piping (20%)
Subtotal Opinion of Probable Costs
$438,000
$250,000
$35,000
$108,500
$50,600
$144,600
$1,026,700'
Flow equalization basin
Basin construction
Pumping equipment
Electrical (15%)
UC (7%)
Sitework and Yard Piping (20%)
Subtotal Opinion of Probable Costs
$970,000
35,000
$151,000
$70,500
$201,000
$1,427,0002
'With allied costs the Total is $1,912,700
2With allied costs the Total is $2,658,500
This report recommends that the centrate be treated biologically to nitrify the waste stream
prior to reintroduction to the activated sludge process.
9.13 Biological Dewatering/Drying Alternatives
The dewatering process is used to reduce the volume of stabilized biosolids prior to transport
to land application.
9.13.1 Alternatives Considered
Redundancy for the existing high capacity centrifuge will be resolved by either a new 270
• gpm centrifuge or a new belt filter press. The new centrifuge or belt filter press could be
HDR Engineering, Inc.
City, of Yakima, WA
Biosolids Management- October 6, 2000
Page 37
DRAFT
placed in the same location as the existing 80 gpm unit or on an elevated platform with the
IIIexisting 270 gpm centrifuge above the new truck loading facility.
•
•
9.13.2 Alternatives Evaluation
➢ A new belt filter press or centrifuge will provide redundancy and dewater the biosolids
to 22 to 25 percent solids when the existing high capacity centrifuge is out of service.
> Operating a new belt filter press in parallel with a centrifuge will require that the plant
operators have the training on both of these technologies.
The opinion of probable costs of the dewatenng alternatives without cost factors are presented
in Table 9-25.
Table 9-25. Opinion of Probable Cost for Dewatering Alternatives
Unit Opinion of Probable Cost
Second Centrifuge
Centrifuge $451,000
Conveyors $150,000
Electrical (15%) $90,000
UC (7%) $42,000
Sitework and Yard Piping (20%) $120,000
Subtotal Capital Construction Costs $853,000'
Alternate Belt Filter
Belt Filter Press $385,000
Conveyors $150,000
Electrical (15%) $80,500
UC (7%) $37,500
Sitework and Yard Piping (20%) $107,000
Subtotal Opinion of Probable Costs $760,0002
'With allied costs the Total is $1,589,100
2With allied costs the Total is $1,415,900
9.13.3 Preliminary Recommendations
Install a second 270 gpm centrifuge to resolve the redundancy issues.
9.14 Polymer Addition Alternatives
9.14.1 Alternatives Considered
The alternatives impacting the chemical feed requirements are addressed in the solids
handling building section. The preliminary recommendations call for a dry polymer feed and
storage system, a liquid polymer feed and storage system, a new Polyblend DP series system
or an expansion of the current polymer system tankage.
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
Page 38
•
•
•
DRAFT
9.14.2 Alternatives Evaluation
➢ The plant staff desire to improve polymer feed and storage with provision for
installation of the polymer storage and feed systems on a common platform. They
also wish to include the ability to utilize both liquid and dry polymers. The current
system is capable of handling liquid and dry polymer, but the staff wish to switch to a
more automated system.
> If the Polyblend DP series system is not chosen, there will be a need for improved
handling facilities in the existing polymer system's dry polymer including a pallet
lifting system for dry polymer bags.
➢ The Polyblend DP series system will not require as much solids handling building
space, and has the ability to handle both liquid and dry polymer. The automatic mixer
blends the polymer solution on an as needed basis. Storage will be provided for the
liquid and dry polymer before they are introduced to the Polyblend DP series feed
system.
The opinion of probable costs of the polymer addition alternative without cost factors are
presented in Table 9-26.
Table 9-26. Opinion of Probable Cost for Polymer Addition Alternative
Unit Opinion of Probable Cost
Polyblend DP series feed system
Liquid Polymer Storage
Dry Polymer Storage/Mixing Tanks
Subtotal Costs
Electrical (15%)
UC (7%)
Sitework and Yard Piping (20%)
Subtotal Opinion of Probable Costs
$90,000
$70,000
$209,000
$369,000
$55,400
$25,800
$73,800
$524,0001
'With allied costs the Total is $976,200.
9.15 Solids Handling Building Alternatives
The objective to the facility planning effort is to prescribe a preferred layout for the solids
handling building components. Two preliminary layouts were developed for the solids
handling building. Figures 9-3, 9-4a and 9-4b present the two alternative site layouts for
build -out conditions. The primary difference between the two configurations is the location
of the centrifuges and hopper facilities.
HDR Engineering, Inc
City of Yakima, WA
Biosolids Management- October 6, 2000
Page 39
•
•
•
DRAFT
9.15.1 Alternatives Considered
There are two solids handling building layouts that are under consideration. The basic
difference between the two layouts is the location of the dewatenng equipment and sludge
hopper. One alternative, shown in Figure 9-3, has these units in their present locations while
the other alternative, shown in Figure 9-4 (a & b), relocates them above the solids loadout
facility.
The opinion of probable costs of the solids handling building alternatives without cost factors
are presented in Table 9-27.
Table 9-27. Opinion of Probable Cost for Solids Handling Building Alternatives
Unit Opinion of Probable Cost
Retrofit existing unit configuration
Solids Handling Building
Conveyor system
Misc. sludge hopper repairs
Noise control room
Air quality modifications
Subtotal Costs
Electrical (15%)
UC (7%)
Sitework and Yard Piping (20%)
Subtotal Opinion of Probable Costs
$875,0001
$250,000
$10,000
$50,000
$75,000
$1,260,000
$189,000
$88,200
$252,000
$1,789,2002
New solids loadout platform alternative
Solids Handling Building
Centrifuge relocation
Relocate sludge hopper
Misc. sludge hopper repairs
Conveyor system
Noise control room and elevated platform
Air quality modifications
Subtotal Costs
Electrical (15%)
UC (7%)
Sitework and Yard Piping (20%)
Subtotal Opinion of Probable Costs
$975,000'
$60,000
$20,000
$10,000
$75,000
$75,000
$75,000
$1,290,000
$193,500
$90,300
$258,000
$1,831,8003
'From Table 9-23
2With allied costs the Total is $3,333,300.
3With allied costs the Total is $3,412,600
9.15.2 Alternatives Evaluation
➢ If the dewatering units are moved, the biosolids hopper will be relocated above the
solids loadout facility with a new conveyor system.
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
Page 40
•
•
•
DRAFT
➢ If the dewatering units remain in place, a vertical conveyor will be installed that is
attached to the existing biosolids hopper and extends to the centrifuges and solids
loadout facility.
> Retrofits to the biosolids hopper will include drains, level measurement, and point
source foul air control.
> Relocating the centrifuges and building a new biosolids hopper will eliminate the need
for additional conveyor length in the solids handling building.
HDR Engineering, Inc.
City of Yakima, WA
Biosolids Management- October 6, 2000
Page 41
6
Z
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HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
R. HORNBAKER
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
DRAWING S FULL S ZE IF NOT
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RETAIN
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104'-6"
105-6"
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SCALE 3/16"=1'-0"
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HDR Engineering. Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
R. HORNBAKER
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.
0
0
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Figure Number
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7'-4"
TRUCK LOADING
AREA
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N
/
0
N
0
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\ \
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104'-6"
105-6"
MAIN FLOOR
SCALE 3/16"=1'-0"
//
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6"
HDR Engineering. Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
R. HORNBAKER
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.
0
0
0
CO
0
z
NEW SOUDS
LOADOUT
PLATFORM
ALTERNATIVE
Figure Number
9-4a
6
Z
0
5
4 1 3 1 2 1 1
105'-6"
19,-0"
85'-0"
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29'-0"
16'-0"
6„
45'-6"
4'-74"
/
13'-0"
5'-0"
13'-0"
5' 0"
11'-0"
7'-104"
59'-6"
/1
105'-6"
SECOND FLOOR
SCALE 3/16"=1'-0"
/
6"
6"
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
R. HORNBAKER
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
DRAWING S FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
0
a
0
m
z
NEW SOUDS
LOADOUT
PLATFORM
ALTERNATIVE
Figure Number
9-4b
00
11
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in
SOLIDS HANDLING
BUILDING
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101
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13'-0"
5'-0"
13'-0"
5' 0"
11'-0"
7'-104"
59'-6"
/1
105'-6"
SECOND FLOOR
SCALE 3/16"=1'-0"
/
6"
6"
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. DOLSBY
Drawn
R. HORNBAKER
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
THIS UNE IS ONE INCH WHEN
DRAWING S FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
0
a
0
m
z
NEW SOUDS
LOADOUT
PLATFORM
ALTERNATIVE
Figure Number
9-4b
DRAFT
• 9.15.3 Recommendations
This study recommends that the solids handling building be expanded to the west, the existing
dewatering unit and a new dewatering unit be installed on an upper floor above a load -out
facility, a new liquid and dry polymer system and a rectangular DAFT unit be installed in the
existing solids handling building, and the existing solids laboratory be expanded.
9.16 Biosolids Utilization Alternatives
Dewatering of biosolids is performed weekly in a batch mode which normally requires
approximately 30 to 35 hours of continuous centrifuging. Dewatering could be performed
only during daylight hours but has the following additional costs:
➢ Increase in polymer addition to achieve the same dewatered solids content due to
repeated startups and shut downs.
➢ Increase in the number of hours of operation due to repeated startups and shutdowns.
After each shutdown of the dewatering system, an additional hour of equipment
cleanup and an additional 30 minutes of startup are required to achieve the same
dewatered solids throughput. For every 10 hours of operation, only 8'h hours of actual
dewatering are accomplished in the intermittent batch process.
Biosolids are dewatered to the 20-24 percent total solids range.' The dewatered biosolids are
transported to local agricultural fields during daylight hours while the dewatering process is in
operation. Typical operations have been to temporarily store biosolids dewatered during non -
daylight hours on the plant site for hauling the following day.
9.16.1 Design Criteria
Biosolids production at the facility in 1999 was approximately 1,500 dry tons. At the
minimum dewatered solids content of 20 percent, this equates to 7,500 wet tons per year or
230,000 cubic feet of biosolids to transport and store each year. During the peak production
months of June through October, 200 dry tons or 1,140 cubic yards, of solids are hauled each
month. Average output during the weekly dewatering process is 7 truckloads.
The dewatered solids are removed during daylight hours from the treatment plant site as they
are processed. Biosolids are temporarily stored at the plant site either on the asphalt storage
pad or in the 20 and 30 cubic yard trailers during non -daylight hours. Using only the existing
two trailers to store and haul the biosolids is adequate only during the summer months when
there are 12 to 14 hours of daylight. During the fall, winter, and spring, the production
capacity of the dewatering centrifuge exceeds the available storage capacity of the two
trailers. Consequently, biosolids are deposited on the asphalt storage pad and reloaded into
the trucks during the daylight hours. Rain, ice and snow will occasionally necessitate the
• 'Biosolids in this range are actually 76 to 80 percent water.
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City of Yakima, WA
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suspension of hauling activities to the land application site due to unsafe road or site
• conditions for the tractor -trailer that is used to transport the biosolids.
9.16.2 Alternatives Descriptions
The following alternatives for biosolids processing and handling were investigated:
> Historical process of storing the solids at the plant site and removing twice each year.
> Move the entire treatment facility to a location away from populated area.
➢ Continue the current method of dewatering and hauling.
> Provide biosolids storage for an entire year on-site.
➢ Provide 3 months of storage at the wastewater treatment plant for inclement winter
weather.
➢ Provide 3 months of storage at the agricultural fields, and one week of storage at the
wastewater treatment plant for periods of inclement weather.
> Landfill of biosolids after digestion in a permitted site.
➢ Sludge incineration and elimination of the anaerobic digestion and biosolids hauling
process.
> Lime stabilization of the biosolids.
9.16.2.1 Historical Practice
Historically, until the summer of 1998, biosolids were dewatered and stored at the plant site
and transported to the agncultural fields during the spring and early fall months. This method
of dewatering and storage was successful in meeting the needs of the Yakima Regional
WWTP and in meeting the needs of the owners of the land application sites. Design
considerations for this alternative are:
> Open biosolids storage on the existing asphalt storage pad.
> One new truck tractor.
➢ Garage facility for three truck tractors with associated HVAC.
> Purchase or lease of 2,000 acres of land for a utilization site to ensure City control of
the site.
9.16.2.2 Move the Treatment Facility
Moving the treatment facility away to a less populous area is one solution for the existing site.
The cost of approximately a hundred million dollars eliminated this option from further study.
9.16.2.3 Continue the Current Method of Dewatering and Hauling
Beginning in the fall of 1998, biosolids have been hauled from the facility as they are
processed, except for times when foul weather or darkness precluded hauling. To continue
this practice additional hauling equipment is required. During the fall, winter, and spnng
months, the quantity of biosolids processed during hours of darkness exceeds the storage
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capacity of the two existing trailers. Using current production rates, a minimum of four 30
cubic yard capacity trailers are required to provide adequate storage after dark. In addition to
the trailers, an additional tractor should be purchased to minimize down time and the storage
duration for biosolids at the facility during daylight hours. Design considerations for this
alternative are:
➢ Storage of daily biosolids production in 30 cubic yard trailers with haul to land
application site during daylight hours.
➢ One new truck tractor.
➢ Garage facility for three truck tractors with associated HVAC.
➢ Purchase or lease of 2,000 acres of land for a utilization site to ensure City control of
the site.
9.16.2.4 One -Year of Storage of Biosolids at the Plant Site
This alternative considers a storage building with a minimum storage capacity of 10,000 wet
tons of biosolids. The building includes provisions for an enclosed section for composting,
and associated HVAC and air emissions control. The footprint for this storage facility is
approximately 2.6 acres. The facility is sized to store 12 months of biosolids. It is anticipated
that a spring hauling period will not be possible due to wet fields, and/or late start of the
planting season, due to unseasonably cold temperatures. Normally, the biosolids would be
hauled twice each year, once in the spring, prior to the planting season, and again in the fall,
after the harvest is complete. There have been years where the fields were too wet in the
spring and all hauling was delayed until the fall. Design criteria for this alternative are:
➢ Biosolids storage facility for 10,000 wet tons.
➢ As the biosolids are dewatered, they will be hauled and immediately stored in the
facility.
➢ Air emission control for on-site storage facility.
➢ One new truck tractor.
➢ Garage facility for three truck tractors with associated HVAC.
➢ Purchase or lease of 2,000 acres of land for a utilization site to ensure City control of
the site.
➢ Contract hauling of biosolids to the utilization site.
9.16.2.5 3 -Months of Storage of Biosolids at the Plant Site
This alternative considers a storage building for three months of dewatered biosolids storage
with provisions for composting and associated HVAC and air emission control. Additional
trucks and trailers are required in this alternative, as the biosolids will be hauled during nine
months of the year. Three months of storage will allow for the storage of biosolids during a
cold wet winter when application to the agricultural fields is not possible. During winters, as
experienced in 1998 and 1999, minimal storage was required as the winters were neither cold
nor wet. During previous winters, when snow was on the ground and temperatures reached —
24°F, hauling operations stopped until the severe weather conditions subsided. The footprint
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for this storage facility is approximately 27,000 square feet or 0.6 acres. Items included in
this alternative are:
> Biosolids storage facility for 2,200 wet tons.
> Biosolids would be dewatered, hauled, and stored in the facility during the 3 month
winter period.
> Air emission control for on-site storage facility.
> One new truck tractor.
D Garage facility for three truck tractors with associated HVAC.
> Purchase or lease of 2,000 acres of land for a utilization site to ensure City control of
the site.
9.16.2.6 3 -Months of Storage at Agricultural Fields and 1 -Week
Storage at Plant Site
This alternative is similar to the previous alternative except the extended storage facility is
sited at the agncultural fields rather than at the wastewater treatment facility. HVAC and air
emission control is not provided, nor required, with a remote storage facility, as the sides of
the storage building are open. Minimal plant site storage must be provided when the roads are
not passable during winter ice and snowstorms. An on-site storage facility sized for
approximately 220 cubic yards or 185 wet tons should provide the necessary "wide spot" in
the biosolids dewatering and utilization process for unforeseen and limited disruption of the
hauling and disposal phase. The footprint for the off-site storage facility is approximately
25,000 square feet with approximately 3,000 square feet of storage and trailer housing at the
facility. Items included in this alternative are:
> Open Biosolids storage facility for 2,200 wet tons at a remote location.
➢ One new truck tractor.
> Garage facility for three truck tractors with associated HVAC.
D On-site biosolids storage facility for 185 wet tons.
> Air emission control for on-site building.
> Purchase or lease of 2,000 acres of land for a utilization site to ensure City control of
the site.
9.16.2.7 Landfill Disposal of Biosolids
This option considers transporting the digested and dewatered biosolids to the Cheyne
Landfill for burial.2 The previous criteria described in the option for Continue the Current
Project of Dewatering and Hauling will also apply to this option. The additional tipping fee
cost to the City is approximately $20/wet ton of material transported. As previously
discussed, biosolids consist of approximately 75 to 80 percent water. The additional cost of
approximately $150,000 annually would be incurred with this option. The City would not
need to acquire a 2000 acre site for disposal of biosolids. WDOE regulations discourage
disposal as a utilization option for biosolids. Design considerations for this alternative are:
2 Costs associated with utilization at alternative locations were not calculated.
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City of Yakima, WA
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D. Storage of daily biosolids production in 30 cubic yard trailers with haul to the landfill
during daylight hours.
D. One new truck tractor.
D. Garage facility for three truck tractors with associated HVAC.
9.16.2.8 Incineration of Primary and Waste Activated Sludge
For this alternative, anaerobic digestion is not required. Prior to incineration the sludge must
be dewatered to approximately a 20 percent solids content. Drier solids require less energy to
incinerate. A sludge cake at 25 percent dry solids only burns with enough energy to raise the
combustion temperature to 900°F. An operating temperature of 1350 to 1400°F is required to
achieve complete combustion of solids and reduction of air emissions. Additional energy in
the form of natural gas or fuel oil is required to achieve the desired operating temperatures.
Extensive exhaust gas scrubbing is required to remove the ash and other particulate from the
exhaust gases prior to discharge. Incineration does not necessarily reduce the air emissions in
the facility as air emissions are generated in the dewatering process prior to incineration just
as they are in the dewatering process of digested biosolids. Air pollution is an additional
regulatory problem inherent with the incineration process that is not associated with other
utilization options. Design considerations for this alternative are:
➢ New building with incinerator including sludge storage.
➢ Air emission control for incineration facility.
9.16.2.9 Lime Stabilization of Solids
Like incineration, lime stabilization is normally not used in conjunction with the anaerobic
digestion process. Lime is added to raw sludge to raise the pH above 12 to destroy
pathogenic bacteria. The increase in pH of digested sludge can result in the release of
ammonia and other gases. This would require air emission containment and treatment, or
relocation of biosolids treatment to an off-site location. No organic destruction occurs with
lime treatment. Disposal of the sludge cake could create a situation where the pH could fall to
near 7 prior to drying out which will cause a regrowth of organisms and resulting air
emissions. Approximately 600 to 1,000 pounds of lime are required per dry ton of sludge for
proper stabilization. Truck traffic will be 25 percent greater with this option than with any of
the other land utilization options. A dedicated land application site for biosolids disposal
would be required. The lime treated biosolids may not be acceptable to local area farmers as
the soils in the area already tend to be alkaline. Design considerations for this alternative are:
➢ Storage of daily biosolids production in 30 cubic yard trailers with haul to the lime
stabilization area during day light hours.
➢ Lime mixing and stabilization facility at the land application site.
> One new truck tractor.
> Garage facility for three truck tractors with associated HVAC.
➢ Purchase or lease of 2,000 acres of land for a utilization site to ensure City control of
the site.
HDR Engineering, Inc
City of Yakima, WA
Biosolids Management- October 6, 2000
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• 9.16.3 Alternatives Evaluation
9.16.3.1 Opinion of Probable Cost
Table 9-28 presents an opinion of probable cost for the eight options considered during this
evaluation, 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 are a total of the opinion of probable
costs and the present worth value of the O&M costs.
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City of Yakima, WA
Biosolids Management- October 6, 2000
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•
DOT
Table 9-28 Opinion of Probable Cost and Total Present Worth Cost
Description
Historical
Practice of
On-site
Storage
Landfill
Solids
Incineration
Lime
Stabilization
Current
Method of
Hauling
Daily
Provide 1
Year On
Site Storage
Provide 3
Months On
Site Storage
Provide 3
Months Off Site
Storage and 1
Week On Site
Storage
Facility Costs
$0
$0
$3,000,000
$1,200,000
$0
$2,860,000
$1,221,000
$902,000
Air Emission Control
$0
$0
$250,000
$250,000
$0
$150,000
$100,000
$50,000
Electrical @ 15%
$0
$0
$487,500
$217,500
$0
$451,500
$198,200
$142,800
I/C @ 7%
$0
$0
$227,500
$101,500
$0
$210,700
$92,500
$66,600
Site Work @20%
$0
$0
$650,000
$290,000
$0
$602,000
$264,200
$190,400
Contractor OH & Profit @ 15%
$0
$0
$692,300
$308,900
$0
$641,100
$281,400
$202,800
Contingency @ 20%
$0
$0
$1,061,500
$473,600
$0
$983,100
$431,500
$310,900
Sales Tax @ 8%
$0
$0
$509,500
$227,300
$0
$471,900
$207,100
$149,200
Engr/Legal/Admin @ 25%
$0
$0
$1,719,600
$767,200
$0
$1,592,600
$699,000
$503,700
Truck tractor (1)
$120,000
$120,000
$0
$120,000
$120,000
$120,000
$120,000
$120,000
2000 acre Land Purchase
$1,000,000
$0
$0
$1,000,000
$1,000,000
$1,000,000
$1,000,000
$1,000,000
Total Opinion of Probable Cost
$1,120,000
$120,000
$8,597,900
$4,956,000
$1,120,000
$9,082,900
$4,614,900
$3,638,400
Fuel, Chemical, Tipping Fees
$1,400
$154,000
$28,000
$78,400
$1,400
$7,400
$5,400
$1,900
Personnel
$72,000
$81,500
$150,000
$150,000
$81,500
$150,000
$87,500
$84,500
Present Worth of O&M Costs
$914,700
$2,934,800
$2,218,200
$2,846,300
$1,033,100
$1,961,500
$1,157,700
$1,076,700
Total Present Worth
$2,034,700
$3,054,800
$10,816,100
$7,802,300
$2,153,100
$11,044,400
$5,772,600
$4,715,100
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City of Yakima, WA
Biosolids Alternatives- October 6, 2000
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An initial review of the options was made to determine which alternatives merited further
evaluation. If an alternative had a high potential for air emission; would not meet anticipated
EPA/WDOE regulations; or the capital costs exceeded $6,000,000, the alternative was
dropped from further consideration.
The lime stabilization and incineration options exceeded the air emission potential criteria and
were dropped from further consideration. The historical practice of on-site storage was
dropped from further consideration in favor of the current method of hauling daily to the land
application site. Landfilling of biosolids, while a relatively inexpensive option, did not appear
to meet current or anticipated EPA 503 or WDOE regulations. Incineration and 1 -year of on-
site storage exceeded the $6,000,000 capital cost criteria. Continuation of the current method
of hauling daily, provide 3 -months of on-site storage, or provide 3 -months of offsite storage
with one week of on-site storage, were left for further evaluation.
9.16.3.2 Comparison of Options
Table 9-29 provides a list of subjective evaluation criteria considered for each of the
remaining three options.
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City of Yakima, WA
Biosolids Alternatives- October 6, 2000
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TABLE 9-29. COMPARISON OF OPTIONS
Evaluation Criteria
Continue Current
Method with Property Purchase
Provide 3 — Months of On-site
Storage with Property Purchase
Provide 3 -Months of Off-site Storage
with 1 -Week On-site Storage and
Property Purchase
Meets EPA, WDOE, and
Department of Health Permit
Requirements
This alternative does meet current and
anticipated regulations.
This alternative does meet current and
anticipated regulations.
This alternative does meet current and
anticipated regulations.
Acceptability
This alternative hauls all solids produced
away for the treatment plant except for
periods of inclimate weather
This alternative has all the biosolids
stored on-site in an enclosed building
with air emission control away from
the view of the public.
This alternative has the biosolids stored
off-site and when weather precludes
hauling, provides for enclosed and
ventilated on-site storage with air
emission control.
Potential for off site air emissions
This storage alternative has a slight
potential for off-site air emissions during
inclement weather when biosolids must be
stored on-site to ensure safety of the
personnel during ice and snow conditions.
Minimal potential for air emissions as
solids are enclosed and ventilated
building.
Minimal potential for air emissions as
any solids stored on-site are in an
enclosed and ventilated building.
Proven performance/proven
treatment process
Current practice has been demonstrated
since fall of 1998
Technology to reduce air emissions is
proven and has been demonstrated at
facilities in the Northwest.
Technology to reduce air emissions is
proven and has been demonstrated at
facilities in the Northwest.
Maintenance
Continuing the current method requires
Tess maintenance than either of the storage
alternatives.
An on-site 3 month storage facility
will require slightly more
maintenance than a one-week storage
facility.
This alternative has more maintenance
than the current method but less than the
3 -months of on-site storage.
Ability to implement without
causing additional short-term noise
at site
Short term and long term noise is not an
issue with this alternative as no additional
construction is required.
Short term construction noise will be
a minor issue as construction work
will occur during daylight hours.
Short term construction noise will be a
minor issue as construction work will
occur during daylight hours.
Cost
This is the least costly viable option.
This is the most costly viable option
This is the least costly storage option.
Potential for alternative to become
unacceptable in the future due to
change in law or land use
regulations
Future regulations may affect the storage
of biosolids in trailers.
Covered ventilated storage at the
facility would be the least susceptible
to changes.
The open off-site storage may become
unacceptable. The off-site facility could
be retrofitted with enclosed sides and air
emission control should this become an
issue.
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City of Yakima, WA
Biosolids Alternatives- October 6, 2000
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• 9.16.4 Implementation
Design and construction of the on-site storage facilities will take approximately two and one-
half years to complete. The off-site storage facility could be built in just 10 to 12 months.
The enclosed facilities, with their HVAC and air emission control equipment, will take longer
to design and subsequently construct.
Acquisition of a dedicated land application site, that is directly under the City's control, is
desirable for all the options. Private individuals own sites currently used for biosolids
disposal. If the price of the crops being grown on the sites change, or if the landowner
decides they no longer desire the biosolids, the City must immediately find other land
application sites. Acquisition of a City owned site will eliminate the time consuming, and
expensive, task of trying to find and certify suitable alternative sites for land application.
9.16.5 Recommendations
The City of Yakima requires a dedicated and reliable biosolids utilization option that meets
the current and future EPA and WDOE regulatory requirements, while limiting air emissions.
The three viable utilization methods recommended for further evaluation are:
> Continuation of the current method of utilization. Since the summer of 1998 the
hauling of the biosolids to a remote site for land application has proven to be adequate
with the addition of transport equipment.
➢ Construct an off-site storage facility in conjunction with an on-site enclosed facility.
The current method has been successful in part because of the mild weather that has
allowed biosolids hauling throughout the winter. The fall -winter -spring season of
1998 and 1999 in the Yakima valley is not typical of previous years, nor was it typical
of normal winters, when the hauling operation was interrupted due to inclement
weather conditions. Typically, winter weather conditions can stop the hauling
operation for a few days to a week, and conditions at the land application site can
delay the spreading of biosolids for more than a few months. Planning in advance for
these inclement weather conditions will reduce the storage of biosolids on-site and
potential air emissions from the facility. Construction of a 3 -month off-site storage
facility and construction of a 1 -week on-site facility with air emission control will
allow the City the necessary flexibility when weather conditions prevent hauling or
land application of biosolids.
> Construct an on-site storage facility to contain the biosolids produced during 3 months
of inclement weather. This is very similar to the previous alternative except the
biosolids are stored at the facility rather than at a remote location.
Continuing the hauling/ utilization option initiated in the late summer of 1998 has the least
cost. This alternative does have a potential for off-site air emissions during periods of
inclement weather when biosolids need to be stored on-site. Building off-site storage with
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BIOSOLIDS MANAGEMENT - October 6, 2000
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• provisions for an on-site enclosed storage, is the preferred alternative, and will reduce the
potential for off-site air emissions.
The purchasing or leasing of 2,000 acres of land for a biosolids utilization site will provide the
City guaranteed control and reliability of a utilization site. Availability of current utilization
sites depend on the economy and market value of the crops. Biosolids can only be placed on
specific agricultural crop lands and, if that particular crop's market value is low, the land may
not be cultivated in a particular year. When this occurs, other sites must be found or the
biosolids must be stored.
For full implementation of any of the options, the following items are common to them all:
> Garage facility for three truck tractors with associated HVAC.
> Purchase or lease of approximately 2,000 acres for a long term and reliable land
application site for biosolids.
9.17 Current Staffing
The Yakima Regional WWTP staff currently perform all of the functions related to biosolids
management in addition to their plant operation duties. This arrangement has worked well
because staffing resources have always included biosolids related work. As the volume of
biosolids has increased, and the level of regulation driven management increased, the existing
Yakima Regional WWTP staff have maintained an effective presence on both plant and
biosolids management work.
Tasks related to on-site biosolids management activities include:
➢ Solid stream process operations (debris removal, pumping, thickening, digestion,
storage, lagoon management, dewatering, dewatered storage, and drying bed
maintenance).
> Process control for solids stream processes.
➢ Laboratory venfication of biosolids quality.
> Optimization of dewatering system (polymer trials, centrifuge operation).
> Biosolids quality enhancement activities (lime treatment, Class A treatment,
composting).
> Truck loading and hauling of biosolids, screenings, and grit.
➢ Maintenance of all processing and handling equipment and control systems.
The tasks related to the off-site biosolids reuse activities include:
➢ Finding suitable application sites.
> Meeting with the landowners and their neighbors.
➢ Coordinating site survey and soil investigations.
> Application site design and loading rates.
➢ Application site permitting.
> Implementing public information and education programs.
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➢ Coordinating and attending public meetings.
➢ Contracting and scheduling of biosolids haul.
➢ Monitoring the biosolids application process to verify compliance with site permit
including pre- and post -application monitoring.
➢ Quickly and effectively responding to problems and complaints.
➢ Coordinating biosolids quality analysis.
➢ Staying up to date on regulations, and issues affecting the biosolids program.
➢ Represent the Yakima Regional WWTP interests on regional biosolids management
matters through the Northwest Biosolids Management Association.
➢ Program budgeting.
D. Hiring and supervising consultants, permanent staff, and seasonal staff needed to
perform these various activities.
The level of effort required to properly administer the biosolids management activities is
extensive. Most, if not all, of the on-site activities are part of what is normally considered
plant operations tasks. As the plant grows in size and new processes are added, trained staff
will be needed to maintain adequate operation of the system. Assessment of operating staff
size should be a regular part of plant management planning and budgeting. Depending on the
range of options chosen by the city, a staffing analysis should be performed in conjunction
with the design of these improvements.
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CITY OF YAKIMA
BIOSOLIDS MANAGEMENT - October 6, 2000
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• 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/1 21
10.4.9 Spot Excavation and Repair 22
10.4.10Safety Concerns 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
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COI.1 FCTION FACILITIES - OCTOBER 6, 2000 PAGE i
•
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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 COI I FCTION FACILITIES - OCTOBER 6, 2000 PAGE 1
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 Pipe Material Joint Material
Prior to 1930 Vitrified Clay Mortar
1930-1945 Concrete Mortar
1945 -mid 1950s Concrete Mastic
mid 1950s -late 1960s Asbestos Cement and Concrete Rubber Ring
Since the late 1960s Concrete, PVC 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 Collection System Inventory'
Basin Designation 5" to 12" 15" to 18" 20" to 27" 30" to 48"
A 180,880 8,288 22,120 8,599
B 322,041 35,493 11,197 --
C 187,377 4,130 5,868 226
D 57,303 15,630 25,078 12,302
E 541,733 30,654 18,832 934
F 45,926 -- 2,132 4,723
Total 1,335,260 96,181 85,228 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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 2
op
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•
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•
AHTANUM ROAD
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RACE STREET
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K—MART
LIFT STATION
YAKIMA
REGIONAL WWTP
RUDKIN ROAD
LIFT STATION
•
[RUDKIN ROAD
HDR Engineering, Inc.
CRY or YAKIMA
YAKIMA REGIONAL
FACILITY
WASTEWATER TREATMENT
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 IS FULL SIZE. IF NOT
ONE INCH, SCALE ACCORDINGLY.
oa
0
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z
EXISTING
WASTEWATER
SERVICE
Figure Number
10-1
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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 Submersible 4th Street and P 2 150
• Race Submersible 15th Street and Race 2 375
• Beach Vacuum Chalmers Street 2 100
• Carriage Hill Dry Well Gravity 46th Avenue 2 150
Centrifugal
• Lake Aspen Vacuum Aspen 2 75
• Stonehedge Submersible Grinders 66`h and Scenic 2 150
• Sierra Estates Submersible Grinders 96th and Tieton 2 150
• K -Mart Vacuum Kmart 2 75
• Lakeside Submersible 40th and Fruitvale 2 140
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 Ott' 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 electncal panel
doors at some lift stations are 1 -inch off the ground causing high snow or rains to cause
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000 PAGE 4
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tnpping 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 dned 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.
III 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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CITY OF YAKIMA
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, imgation 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, 6"' 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 dunng 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
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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 1st 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 16th Avenue South, and a percentage of the 8 -
inch laterals discharging to the trunk sewer in the vicinity of 12`h 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 point 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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 7
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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 I/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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ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 8
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DRAFT
> Summer - July 7, 1986 to September 7, 1986
Data gathered dunng these periods provided measurements of the low -flow season
(winter) and the maximum flow season (late summer). The first two sampling penods
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 imgation 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 nse, 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/I 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. I/1 flow from
the City of Union Gap and the Terrace Heights Service Distnct is another possibility.
The I/1 values estimated during the irrigation season for 1974, 1979, and 1986 totaled
12.9 mgd, 6.8 mgd and 9.9 mgd respectively. The I/I estimate from 1974 was based on
the minimum daily flow being considered as entirety extraneous flow. It resulted in a
HDR ENGINEERING, INC
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 9
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Figure 10-2. Yakima Urban Area Comparison of Recorded Flows from 1975, 1979 and 19
Sewage Flow (mgd)
24
20
16
12
8
4
0
12 2 4 6 8 1012 2 4 6 8 1012 2 4 6 8 1012 2 4 6
(am) (Pm) (am) (pm)
Time
September
12, 1985
/
-V.,,.
—�
N
—
N N
/ /
/
/
/
September
September
17, 1975
6, 1979
I
I I
I
I
1
1
1
1
I I 1
1 I 1
11
1
12 2 4 6 8 1012 2 4 6 8 1012 2 4 6 8 1012 2 4 6
(am) (Pm) (am) (pm)
Time
•
DRAFT
large 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
37
14
5.7
1.3
1.3
0.8
0.31
2.3
2.5
46
16
57
0.83
14
11
0.31
1 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/I that flows into the
collection system. In the fall of 1990 the City began an aggressive I/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) entenng the Yakima Regional WWTP.
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 11
• •
6
5.5
5
4.5
v
4
m
E 3.5
3
0
c 3
v
o
E 2.5
N
w 2
1.5
1
0.5
0
0
Figure 10-3. 1997 to 1998 Yakima Urban Area Average Daily Inflow versus
Rainfall
•
y=2.859x-
0.603
R
0
0.25 0.5 0.75 1 1.25 - 1.5
Rainfall (inches/day)
1.75
2
2.25
2.5
Estimated Inflow (mgd)
• • •
Figure 10-4. 1974 to 1975 Yakima Urban Area Average Daily Inflow Versus Rainfall
4
3.5
3
2.5
2
1.5
1
0.
0
Rainfall (inches/day)
❑ Inflow Data
— Regression Line
2
❑
0
❑
u
❑
❑
0
0
0
Y=0.01
0
+ 2.53x
•
■
0
0
❑•
IL
n
n7
n4
(1R
08
1
1.
Rainfall (inches/day)
❑ Inflow Data
— Regression Line
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 critena 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 critena 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 dunng 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 cnterion.
10.3.3.3 Evaluation of Nonexcessive Infiltration and Inflow
Infiltration and inflow (I/I) 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 Evaluation'
Dates Average Daily Flowrate Average Daily
(mgd) Flowrate (gpcd)
•
•
June 6 to 20, 1997
July 2 to 15, 1997
August 1 to 14, 1997
June 9 to 23, 1998
July 5 to 19, 1998
August 2 to 15, 1998
September 1 to 15, 1998
Total Average
12.0
16.7
14 1
12.0
13 1
14.5
14.3
152.4
210.8
178.0
151 4
165.5
183.5
181.6
1 From influent Yakima Regional WWTP wastewater flow data.
13.8 174 7
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 critena of 120 gpd/capita. However, the infiltration component of 48
gpd/capita which is equivalent to approximately 480 gpad, generally conforms to the EPA
non -excessive critena.
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:
D 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 AINEVIS 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 clean 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
4110 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 entenng 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 nng
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 monitonng and enforcement should help to
ensure its success.
The City of Yakima has recently began discussions with the Yakima Health Distnct 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, tnsodium 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,
industnal 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 AIlvI1vIS number. Copies of the
revised maps are distributed to all wastewater map holders on a penodic 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, buned 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/I
Pnor 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/1 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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O 10.4.9 Spot Excavation and Repair
and repair is to determine the location of problem areas
The objective of spot excavation p
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 cementatious coating. A pnvate
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,
tnpod, 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 wntten 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 11 1 15 1 20 1 20 1 40 1 40 2 80
Maintenance Man I 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 1 15 1 20 1 20 1 40 1 40 2 80
Auto Equip. Operator 1 40 1 40
Photo Inspection Technician 1 40 1 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 1 40
Sewer Maintenance Staff 6 80 6 110 9 220 16 620 27 1060 39 1560
Maintenance Mechanic 113
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 AIMMS
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, 1,200 if/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, 700 If/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 pnoritize 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,
5001f/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, 1000 If/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, 3001f/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 matenals 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
IIIEach 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) 5
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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0 Table 10-8. City of Yakima Collection System Expenses
Description Estimated 1998 Estimated 1999 Estimated 2000 Estimated 2001
Staff Costs' $871.832 $912,044 $954,113 $998,128
Operating Supplies, Maintenance2 $114,124 $119,830 $125.822 $132,114
Machinery and Equipment3 $205,923 $216,219 $227,030 $238,381
City Services/Ancillary Costs4 $494,628 $518,611 $543,790 $570,230
Total $1,686,507 $1,766,704 $1,850,755 $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
$36,151
$20,211
$198,662
Estimated 1999
$89,090
$60,157
$41,574
$27,519
$218,340
Estimated 2000
$102,453
$61,681
$47,810
$28,895
$240,840
Estimated 2001
$117,822
$63,432
$54,982
$30,340
$266,576
1 Includes salaries and wages, and personnel benefits. Approximately $75,000 per I+ 1h 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 II 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
dnnking 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 II 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
> public involvement and participation
> illicit discharge detection and elimination
➢ construction site storm water runoff control
➢ post -construction storm water management
> 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.
> 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.
IP ➢ 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' 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 11 Storm
Water Regulations, and would require increased staffing for implementation of
this MCM.
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The menu of Construction Site Runoff Control would be adopted as Design
Standards. Both the "Drainage Critena 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'/z 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' 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 Critena 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 nparian 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 nparian 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.
> Program Administration. Although not directly described in the EPA Phase lI
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 industnal customers; customer response issues; council presentations;
coordination with other City activities; and other duties. A full-time clencal 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, engineenng, 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
s 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 (1)
$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 (1)
$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 penod. The following identifies the staffing and activities which may occur.
➢ Year 1 (2003)
• Staffing:
• Program Manager
• Public Relation Specialist
• Clerical Assistant
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 38
•
DRAFT
• 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 "npanan habitat"
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 39
•
DRAFT
➢ 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 Dram 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
$1,080,000
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
HDR ENGINEERING, INC.
CITY OF YAKIMA
ANALYSIS OF EXISTING WASTEWATER COLLECTION FACILITIES - OCTOBER 6, 2000
PAGE 40
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
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGEi
DRAFT
• 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 cnteria 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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 1
•
DRAFT
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%
HDR ENGINEERING, INC
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 2
•
DRAFT
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:
➢ 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.
➢ 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.
➢ A system of wastewater treatment charges will be developed based on the flow
and strength of the wastewater received from the vanous 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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000 PAGE 3
•
DRAFT
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 companson. 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
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000 PAGE 4
•
DRAFT
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 tittle 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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CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COI I.FCTION STRATEGIES - OCTOBER 6, 2000
PAGE 5
•
DRAFT
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.
HDR ENGINEERING, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 6
DRAFT
• 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 scenanos of the peak flows which define maximum
hydraulic conditions for the collection system, treatment plant, and effluent outfall. One
scenano 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 cnteria. 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 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 1714 0.22 0.52
309 W6MH53 21 15 278.1 114 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 4201 177 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
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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 E21MH17 4975 15 369.5 113 2.52
305A W20MH3A 4169 8 346.0 0.06 0.26
307 W5MH36 15 8 1714 0.22 0.52
309 W6MH53 21 15 278.1 114 1.39
414 EI7MH4 400 8 74.8 0 74 4.54
509 W32MH7 581 18 4201 177 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 E30MH 16 2374 24 367.1 10.67 11 972
212 E21MH11 480 24 389.2 10.27 1173
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 1714 0.22 0.58
309 W6MH53 21 15 278.1 114 1.55
404 E62MH2 526 30 512.4 1140 2199
406 E56MH3 5443 30 6491 1147 2168
407 E40MH5B 5448 21 606.0 1147 20.05
412 E41 MH 13 5453 21 528.1 8.39 18.88
416 E8MH73 1675 18 168.3 3.53 17.53
418 W17MH2 2368 18 488.5 6.04 16.73
506 W31MH10 4013 8 229.5 162 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 4201 177 8.69
516 W29MH37 5103 8 316.9 0.22 105
517 W3IMH7 4007 12 6117 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 I O I MH 13 3265 10 252.8 149 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 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 E30MH 16 2374 24 367 1 10 67 11.972
212 E21MH11 480 24 389.2 10.27 1173
215 W4MH26 2468 8 269.8 0 77 1 12
217 E21MH17 4975 15 369.5 113 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 1714 0.22 0.58
309 W6MH53 21 15 278.1 114 1.55
401 E641W45 763 24 415.5 15.17 22.36
412A E17MH95 5194 27 334.8 8.87 10.92
414 EI7MH4 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 1108
506 W31MH10 4013 8 229.5 162 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 18 420.1 177 8.69
516 W29MH37 5103 8 316.9 0.22 105
517 W31MH7 4007 12 6117 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
6
5
4
3
r+1
SCALE
1500 0 1500 3000
SCALE FEET
LEGEND:
EXISTING SANITARY SEWER PIPING
PARALLEL PIPES REQUIRED
W68MH56
W101MH13
SUMMITVIEW AVENUE
1
Th
FRUITVALE BOULEVARD
W4MH26
E21 MH55
W UNCOLN AVENUE
E21MH17
E21MH59
E21MH11
E28MH76
E YAKIMA AVENUE
TIETON DRIVE
S 72N0 AVENUE
WIDE HOLLOW ROAD
ZIER ROAD
BOULEVARD
W54MH35
W54MH6
W29MH37
S 40TH AVENUE
AHTANUM ROAD
W WASHINGTON AVENUE
W31MH7
W31MH10
W32MH7
W32MH4A
iripm
...Y441
oma.
W5MH36
W17MH02
WI 7MH92
S 16TH AVENUE
E NOB HILL BOUL
RD
E30MH16
INTERSTATE 82
E MEAD AVENUE
YAKIMA
REGIONAL WWTP
RUDKIN ROAD
'—E62MH2
E41MH13
E40MH58
E56MH3
W6MH53
E8MH73
AHTANUM ROAD
HDR Engineering, Inc.
CITY OF YAKIMA
YAKIMA REGIONAL
WASTEWATER TREATMENT
FACILITY
WASTEWATER
FACILITIES
PLAN
Project Manager
A. KRUTSCH
Designed
C. OOLSBY
Drawn
E. MCDERMOTT
Checked
Project Number
06539-035-002
Date
FEBRUARY 2000
THIS UNE 6 ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
c
0
a
0
a
z°
BUILD -OUT
SPREADSHEET
MODEL COLLECTION
SYSTEM RUDKIN
ROAD FLOW
THROUGH
IMPROVEMENTS
Figure Number
6
5
4
3
r,
SCALE
1500 0 1500 3000
iiiii
SCALE FEET
LEGEND:
EXISTING SANITARY SEWER PIPING
PARALLEL PIPES REQUIRED
W68MH56
W101MH13
SUMMITVIEW AVENUE
TIETON DRIVE
FRUfNALE BOULEVARD
W4MH26
E21MH55
W LINCOLN AVENUE
E21MH17
E21MH11
E28MH76
E YAKIMA AVENUE
ENGLEW000 AVENUE
1
S 72ND AVENUE
WIDE HOLLOW ROAD
ZIER ROAD
W NOB HILL
J
BOULEVARD
E NOB HILL B0ULE4
RD
INTERSTATE 82
W54MH35
W54MH6
W29MH37
S 40TH AVENUE
E30MH16
E641W45
YAKIMA
REGIONAL WWTP
E MEAD AVENUE
W WASHINGTON AVENUE
W31 H7
W31MH10
W32MH7
W32MH4A
W20MH3A
AHTANUM ROAD
W5MH36
W17MH02
W17MH92
S 16TH AVENUE
r
E17MH4
El 7MH95
W6MH53
E8MH73
AHTANUM ROAD
7
E42MH90
RUDKIN ROAD
E32MH91
HDR Engineering. Inc.
10111
111
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
THIS UNE IS ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
0
z
BUILD -OUT
SPREADSHEET
MODEL COLLECTION
SYSTEM RUDKIN
ROAD BYPASS
IMPROVEMENT
Figure Number
11-1a
DRAFT
• Table 11-6. Existing Collection System Expansion for the Rudkin Road Flow
Scenario'
Subbasin From Manhole Parallel Pipe
Number Number
Parallel Pipe
Diameter, in
Parallel Pipe
Run Length2, ft
Estimated Pipe
Capacity, cfs
111G
217
305A
307
309
416
418
508
509
516
520A
E28MH76
E21MH17
W20MH3A
W5MH36
W6MH53
E8MH73
W17MH2
W32MH4A
W32MH7
W29MH37
W54MH6
3112P
4975P
4169P
15P
21P
1675P
2368P
2874P
581P
5103P
4603P
8
18
10
10
10
15
8
8
18
8
8
437 7
369.5
346.0
171 4
278.1
168.3
488.5
495 6
420.1
316.9
305 4
0 44
1.84
0.39
0.39
0.27
3.56
0.38
0.52
1 77
0.22
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
Number
Parallel Pipe Parallel Pipe Parallel Pipe Run
Number Diameter, in Length2, ft
Estimated Pipe
Capacity, cfs
111G E28MH76 3112P
217 E21MH17 4975P
305A W20MH3A 4169P
307 W5MH36 15P
309 W6MH53 21P
414 E17MH4 400P
509 W32MH7 581P
516 W29MH37 5103P
520A W54MH6 4603P
8
18
8
10
10
15
18
8
8
437 7
369.5
346.0
171 4
278.1
74.8
420.1
316.9
305 4
044
1.84
0.22
0.39
0.27
3 93
1 77
0.22
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
Number Number Diameter, in
Parallel Pipe
Run Length2, ft
Estimated Pipe
Capacity, cfs
111G
202
212
215
217
232B
305A
E28MH76 3112P
E30MH16 2374P
E21 MH 11 480P
W4MH26 2468P
E21MH17 4975P
E21MH55 466P
W20MH3A 4169P
8
12
12
8
24
8
10
437 7
367 1
389.2
269.8
369.5
137.9
346.0
0.44
1.59
2.29
0.40
3 97
0 99
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 1714 0.39
309 W6MH53 21P 12 2781 0.45
404 E62MH2 526P 30 512.4 12.35
406 E56MH3 5443P 27 6491 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 W17MH2 2368P 21 488.5 10 75
506 W31MH10 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 15 316.9 116
517 W31MH7 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.
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 E30MH 16 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 10 137.9 179
305A W20MH3A 4169P 10 346.0 0.39
307 W5MH36 15P 10 1714 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 W17MH2 2368P 8 488.5 0.82
501 E42MH90 3640P 8 450 4 0 40
503 E32MH91 3469P 21 247 4 2.81
506 W31MH10 4013P 8 229.5 0 75
507 W17MH92 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 13
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 15 316.9 116
517 W31MH7 4007P 15 6117 479
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
E21MH17 4975P 18 369.5 $113,000
W20MH3A 4169P 10 346.0 $80,000
W5MH36 15P 10 1714 $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 4201 $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 YAKIMA
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
E21MH17 4975P 18 369.5 $113,000
W20MH3A 4169P 8 346.0 $80,000
W5MH36 15P 10 1714 $39,000
W6MH53 21P 10 2781 $65,000
E17MH4 400? 15 74.8 $21,000
W32MH7 581P 18 4201 $128,000
W29MH37 5103P 8 316.9 $74,000
W54MH6 4603P 8 305.4 $71,000
TOTAL $694,000
1Data 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 3671 $0
E21MH11 480P 12 389.2 $96,000
W4MH26 2468P 8 269.8 $64,000
E2IMH17 4975P 24 369.5 $154,000
E21MH55 466P 8 137 9 $33,000
W20MH3A 4169P 10 346.0 $80,000
W5MH36 15P 10 1714 $39,000
W6MH53 21P 12 278.1 $66,000
E62MH2 526P 30 512.4 $254,000
E56MH3 5443P 27 6491 $315,000
E40MH5B 5448P 21 606.0 $225,000
E4IMH13 5453P 21 5281 $198,000
E8MH73 1675P 27 168.3 $83,000
W17MH2 2368P 21 488.5 $184,000
W31MH10 4013P 8 229.5 $0
W17MH92 2106P 18 382.0 $115,000
W32MH4A 2874P 21 495.6 $185,000
W32MH7 581P 30 4201 $214,000
W29MH37 5103P 15 316.9 $86,000
W31MH7 4007P 15 6117 $165,000
W54MH6 4603P 12 305 4 $74,000
W54MH35 4597P 8 677.5 $0
W68MH56 2857P 8 691.8 $161,000
W 101 MH 13 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 Scenario'
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 3671 $0
E21MH11 480P 12 389.2 $96,000
W4MH26 2468P 8 269.8 $64,000
E21MH17 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
E641W45 763P 18 415.5 $124,000
E17MH95 5194P 18 334.8 $100,000
E17MH4 400P 24 74.8 $33,000
E8MH73 1675P 18 168.3 $50.000
W 17MH2 2368P 8 488.5 $0
E42MH90 3640P 8 450 4 $0
E32MH91 3469P 21 247 4 $90,000
W31MHIO 4013P 8 229.5 $0
W17MH92 2106P 8 382.0 $0
W32MH4A 2874P 15 495 6 $135,000
W32MH7 581P 30 4201 $214,000
W29MH37 5103P 15 316.9 $86,000
W 31 MH7 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
TOTAL $1,867,000
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, INC.
CITY OF YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 17
•
DRAFT
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 dust 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 96th
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. 64th Avenue. This line will be routed around the curve in the old Yakima Valley
Transportation Company alignment at Ahtanum Road. As the pipeline crosses 96`h
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. 10`h 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 YAKIMA
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
• D
C
B
A
6
5
4
3
tN
SCALE
2000 0 2000 4000
SCALE
LEGEND:
FEET
EXISTING SANITARY SEWER PIPING
PARALLEL PIPES REQUIRED
TIETON DRNE
WIDE HOLLOW ROAD
WIDE HOLLOW BASIN INTERCEPTOR
SUMMINIEW AVENUE
S 72ND AVENUE
1
F�
L
W NOB HILL BOULEVARD
ZIER ROAD
Z t
_g,
N
S 40TH AV
UE
L.17/—
COOLIDGE BASIN
INTERCE
COWICHE CANYON BASIN INTERCEPTOR
FRUINALEBOULEVARD
SUNTIOES/GLEED BASIN TRUNK
2 I
4III ISI
4 ,„
461 MUM: lath\
1 la :22.1 I I
Illt#1
-N I—AVENU
rill: m4 ILL BOULEVARD
lei Em
IPI 11 MIMI'
r 4 1-1-Mialantrallil , ak
111.11111:11Itill
,ajarib.
TOR
W LINCOLN AVENUE
E YAKIMA AVENUE
W WASHINGTON AVENUE
AHTANU
ROAD
WILEY CITY BASIN TRUNK
S 16TH AVENUE
AIRPORT WEST BASIN LATERALS
AHTANUM ROAD
INTERSTATE 82
YAKIMA
REGIONAL WWIP
RUDKIN ROAD
HDR Engineering, Inc.
1111
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
THIS UNE IS ONE INCH WHEN
DRAWING S FULL SIZE IF NOT
ONE INCH. SCALE ACCORDINGLY.
0
0
0
a
z
BUILD -OUT
COLLECTION
SYSTEM
IMPROVEMENTS
Figure Numoer
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
E 1 7MH4
E21MH55
E21MH11
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
8
10
10
12
18
36
10
12
36
36
36
36
36
36
36
36
36
36
36
36
36
Revised Cost
Estimate' (dollars)
$103,000
$80,000
$39,000
$66,000
$113,000
$39,000
$33,000
$96,000
$220,000
$216,000
$244,000
$234,000
$235,000
$33,000
$185,000
$73,000
$111,000
$189,000
$203,000
$149,000
$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 System' (Cont
From Manhole Parallel Pipe Parallel Pipe Revised Cost
Number Number Diameter, in Estimate' (dollars)
E42MH42 3485
E31 MH5 3644
E32MH90 2375
E32MH90A 3478
E32MH92 3468
E32FE3A 2395
E32MH93 2394
E32MH94 3029
E32MH95 3022
E32MH97 2502
E32MH98 3475
E32MH8 3471
E17MH92 3470
E17MH91 403
EI 7MH 16A 402
E17MH93 656
E 17MH94 3032
E 17MH96 5192
E 17MH97 5191
E17MH98 5190
E8MH91 2491
E8MH92 5167
W17MH92 2106
E30MH 16 2374
W4MH26 2468
E32MH96 2503
W68MH56 2857
W32MH4A 2874
W 101 MH 13 3265
E32MH91 3469
E42MH90 3640
W4IMH10 3822
W 31 MH7 4007
W31MH10 4013
W54MH35 4597
W54MH6 4603
E21 MH 17 4975
W29MH37 5103
E8MH93 5168
E17MH95 5194
E64MH30 5522
36 $173,000
36 $226,000
36 $56,000
36 $41,000
36 $175.000
36 $88,000
36 $180,000
36 $258,000
36 $263,000
36 $171,000
36 $173,000
36 $83,000
36 $140,000
36 $276,000
36 $278,000
36 $266,000
36 $165,000
36 $175,000
36 $169,000
36 $170,000
36 $173,000
36 $189,000
30 $189,000
12 $89,000
8 $64,000
30 $79,000
8 $161,000
30 $246,000
8 $0
42 $196,000
36 $229,000
24 $225.000
15 $165,000
8 $54,000
8 $159,000
12 $74,000
24 $154,000
15 $86,000
27 $319,000
42 $265,000
12 $83,000
Total Cost $9,475,000
I 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
1500 0
G:
SCALE
LEGEND:
SCALE
1500 3000
FEET
EXISTING SANITARY SEWER PIPING
PARALLEL PIPES REQUIRED
W68MH56
W1O1MH13
SUMMITVIEW AVENUE
TIETON DRIVE
FRUFIVALE BOULEVARD
T
ENGL£WOGD AVENUE
\i
,L
S 72ND AVENUE
WIDE HOLLOW ROAD
BOULEVARD
ZIER ROAD
J
AHTANUM ROAD
S 40TH AVENUE
JJ
JJII.
„,,..0“111
"4:41 1 Pr V
m
So*"
440%
to.44,
,h00044
61 I
% 1
NffriniaM4
bk-
W WASHINGTON AVENUE
W32MH7
W32MH4A
W41MH10
W20MH3A
S 16TH AVENUE
W5MH36 E8MH94
W6MH53 E8MH93
W17MH92 E17MH96, E17MH97
E17MH98, E8MH91,
E8MH92
El 7MH95
El 7MH94
W4MH26
E21MH55
W UNCOLN AVENUE
E21MH17
E21MH11
E28MH76
E YAKIMA AVENUE
E30MH16
E17MH91, E17MHMI6A
El 7MH93
E17MH4
AHTANUM ROAD
E32FE3A, E32MH93,
E32MH94, E32MH95
E32MH96
E32MH97. E32MH98
E32MH8, E17MH92
E42MH97, E42MH98, E42MH99
E42MH95, E42MH96
E42MH93, E42M H94
E42MH92
E42MH91
E42MH40
E42MH41, E42MH42,
E31MH5
E32MH91, E32MH90,
E32MH90A, E32MH92
NTERSTATE 82
E64MH30
E641W45
YAKIMA
REGIONAL WWTP
E42MH90
rRUDKIN ROAD
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
THIS UNE 15 ONE INCH WHEN
DRAWING IS FULL SIZE IF NOT
ONE INCH, SCALE ACCORDINGLY.
BUILD -OUT
SPREADSHEET
MODEL COLLECTION
SYSTEM RUDKIN
ROAD BYPASS
IMPROVEMENT
Figure Number
11-3
•
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 penods 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
•
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 pnor 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
Vehicle Storage (14,400 sf)
Office/Administration (2,400 sf)
Restroom/Showers/Lockers (1,200 sf)
Subtotal
Electrical (15%)
Site Work (20%)
Subtotal Costs
Contractor Overhead and Profit (15%)
Subtotal
Contingency (20%)
Subtotal
Sales Tax (8%)
Subtotal
Engineenng, legal and fiscal (25%)
Property Purchase
Opinion of Probable Cost
$864,000
$192,000
$120,000
$1,176,000
$176,400
$235.200
$1,587,600
$238,100
$1.825,700
$365,100
$2,109,800
$175,300
$2,366,100
$591,500
$300,000
Total Opinion of Probable
Construction Cost
$3.257,600
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 Storni 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 budge,
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 Storni 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 YAKIMA
IDENTIFICATION OF SELECTED WASTEWATER COLLECTION STRATEGIES - OCTOBER 6, 2000
PAGE 29
DRAFT
• City of Yakima
Mandatory Wastewater Facilities Plan
SECTION 12
Financial
Planning/Implementation
• October 2000
prepared by
Clint Dolsby
HDR Engineering, Inc.
reviewed by
John Koch
Tony Krutsch
City of Yakima
•
•
•
DRAFT
Table of Contents
12.1 Introduction 1
12.2 Revenue Sources 2
12.3 Components of Sewer Charges 2
12.4 Utility Rates 5
12.4.1 Utility Rates Outside the City Limits 5
12.4.1.1 Policy on Yakima Retail Customers 6
12.4.1.2 Cash and Utility Basis of Accounting 6
12.4.2 Utility Rates Inside the City Limits 7
12.5 Summary of Facility Improvements 8
12.5.1 Wastewater Treatment 8
12.5.2 Collection System 11
12.6 Projection of Facility Improvement Projects Funded From Rate
Revenues 12
12.7 Summary of Facility Improvement Annual Operation and
Maintenance 19
12.7.1 Wastewater Treatment Program 19
12.7.2 Pretreatment/Strong Waste Program 19
12.7.3 Collection System Program 20
12.7.4 Storm Drainage Program 20
12.8 Other Funding Sources 21
12.8.1 Environmental Protection Agency (EPA) 21
12.8.2 Washington Department of Ecology 21
12.8.2.1 The Washington State Water Pollution Control Revolving Fund
Program Funding Allocations 23
12.8.3 Public Works Trust Fund 24
12.8.4 Community Economic Revitalization Board 24
12.8.5 Economic Development Administration (EDA) 24
12.8.6 Public Works Timber Trust 25
12.8.7 Block Grant — General Purpose 25
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGEi
DRAFT
• City of Yakima
•
SECTION 12
Financial Planning/Implementation
12.1 Introduction
The City of Yakima Wastewater Utilities Division finances are separated into four funds.
Each fund has been broken down into service units as identified in Table 12-1.
Table 12-1. City of Yakima Sewer Utilities Department'
Division Service Description
Unit
Wastewater Operating Fund — 473
211 Wastewater collection
213 Surface drainage collection
215 Rudkin Road pump station
232 Wastewater treatment
233 Pretreatment
234 Food processing wastewater
Wastewater Capital Reserves — 472 Major replacement, capital repairs, or minor
capital improvements.
Wastewater Collection System
Project Fund — 476
Capital improvements to reduce 11I, upgrade line
capacity, rehabilitate deteriorated pipes, increase
efficiency in operation and maintenance of the
collection system. Interceptor construction.
Wastewater Facilities Wastewater treatment plant construction and
Project Fund — 478 Rudkin Road construction.
The City of Yakima has performed several cost of service and rate studies, the latest of
which was performed in February of 1997. Connection charges have also been updated
as recently as October of 1998. The City of Yakima is currently facing a number of large
capital investments. Given the financial impact of these improvements, a financial plan
that minimizes the rate impacts to the customers is required.
A rate study consists of three interrelated analyses which are: a revenue requirement
study; a cost of service analysis; and the design of rates. In summary form, a revenue
requirement study concerns itself with the various revenues and expenses for the utility
being analyzed. The revenue requirement analysis indicates the overall need for any
adjustment to the revenue (rate) levels of the utility. Once the revenue requirement
analysis is completed, a cost of service analysis is used to determine the "fair and
HDR ENGINEERING, INC.
CITY OF YA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE I
•
•
•
DRAFT
equitable" allocation of the total revenue requirements to each of the customer classes of
service (e.g owner, non -owner) for the utility. Finally, given a revenue requirement, and
a fair and equitable method to spread these costs to end users, rates are designed to collect
the required revenues.
12.2 Revenue Sources
The Wastewater Utilities Division receives revenue from five customer classes, which are
listed below.
➢ The residential, commercial, institutional, governmental, and industrial customers
inside the city limits connected to the wastewater collection system.
➢ The residential, commercial, institutional, governmental, and industnal customers
outside the city limits connected to the wastewater collection system.
➢ Food product industries inside the City of Yakima whose process (not sanitary)
wastewater is collected and transported through the separate collection system to
the sprayfield adjacent to the Yakima Regional Wastewater Treatment Plant
(WWTP).
➢ The adjacent agencies (City of Union Gap and Terrace Heights Sewer Distnct
with the potential to include the community of Gleed and City of Moxee in the
future) for which the Yakima Regional WWTP provides treatment and disposal
service on a cost -to -treat and a cost -to -transport basis.
➢ The users of the septic handling facilities constructed at the Yakima Regional
WWTP.
The Wastewater Utilities Division also receives revenues from strong waste charges
assessed to commercial, institutional, government, and industrial customers, and from
connection charges.
Under some conditions, additional revenue resources are available from Federal and State
agencies in meeting the total costs of capital improvement projects, both at the Yakima
Regional WWTP and in the City's sewage collection system.
12.3 Components of Sewer Charges
The components of sewer service charges are generally descnbed as follows:
➢ Wastewater Collection Operation and Maintenance Expenses — These expenses
include cost of labor, matenals, chemicals, supplies, equipment, power, and other
items necessary for the operations and maintenance of the City's sewage
collection system, including 9 small lift stations. Wastewater system O&M
expenses apply to those customers connected to the City's collection system, both
inside and outside the city limits. Wastewater system O&M expenses also apply
to the City of Union Gap for the collection system which is downstream of the
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE 2
•
•
•
DRAFT
connection to the City of Union Gap pressure main with the City's collection
system.
➢ Wastewater Treatment Operation and Maintenance Expenses — These expenses
include the cost of labor, materials, chemicals, supplies, equipment, power, and
other items necessary for the operation and maintenance of the Yakima Regional
WWTP. O&M expenses apply to those customers connected to the City's sewage
collection system both inside and outside the City limits, the adjacent agencies
(City of Union Gap and Terrace Heights Sewer District), and the users of the
septic handling facilities.
➢ Food Processing Operation and Maintenance Expenses — These expenses include
the cost of labor, materials, chemicals, supplies, equipment, power, and other
items for the operation and maintenance of the food processing collection and
disposal facilities. O&M expenses apply to those customers directly connected to
the food processing facilities.
➢ Rudkin Road Pumping Station Operation and Maintenance Expenses — These
expenses include the cost of labor, materials, chemicals, supplies, equipment,
power and other items for the operation and maintenance of the Rudkin Road
Pumping Station. Rudkin Road pumping station O&M expenses apply to those
customers both inside and outside the City limits, and to the City of Union Gap.
➢ Surface Drainage Collection Operation and Maintenance Expenses — These
expenses include the cost of labor, matenals, chemicals, supplies, equipment,
power and other items for the operation and maintenance of the storm sewers,
catch basins, and other surface drainage features. Surface drainage collection
O&M expenses apply to only those customers within the City of Yakima.
➢ Tax Expense — The revenues of the Wastewater Utilities Division are subject to a
State Tax. Revenues received from wholesale customers are not subject to the
State Tax. Gross revenues are subject to a City Utility Tax of 14 percent. By
agreement, neither Terrace Heights nor Union Gap pay the City Utility Tax.
➢ Wastewater Treatment Plant Capital Costs — Capital costs are for improvements at
the WWTP that have a useful life of more than one year. They include
engineering, contract purchases, administration, labor, supplies, equipment,
materials and other items. Yakima Regional WWTP costs apply to all customers
served by the WWTP, including food processing customers who discharge waste
during the non -irrigation season.
➢ Wastewater Construction Capital Costs — These capital costs are for
improvements to the collection system that have a useful life of more than a year.
Costs include engineering, contract purchases, administration, labor, supplies,
equipment, materials and other items. Wastewater construction capital costs are
applied appropnately to those customers connected to the City's sewage collection
system, both inside and outside the city limits, and the City of Union Gap.
Rehabilitation and/or replacement of the existing collection system benefits
customers both inside and outside of the city limits. Construction of new
interceptors will be financed by the development community with limited
financial City involvement.
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➢ Debt Expense — Debt expense includes debt service on outstanding bonds (both
pnncipal and interest) as well as costs of short-term borrowing needed to
complete construction projects to be ultimately financed with City bond funds.
Depending on the elements of the system financed, all customers of the facilities
may be subject to debt expense.
Table 12-2 summarizes each of the components of the sewer charges and indicates those
users of the service. Components of the sewer charges have a corresponding relationship
with each of the City's Service Units, as described earlier in this Section.
Table 12-2. Components of Sewer Charges
Sewer System Collection O&M
Inside city
Outside city
City of Union Gap'
Wastewater Treatment Plant O&M
Inside city
Outside city
City of Union Gap
Terrace Heights Service District
Septage Handling Facilities
Food Process Treatment O&M2
Del Monte
Rudkin Road Pumping Station
Inside city
Outside city
City of Union Gap
Surface Drainage Collection
Inside city
Tax Expense
State tax
Inside city
Outside city
Septic handling facilities
Food process customers
City utility tax
Inside city
Outside city
Septic handling facilities
Food process customers
WWTP Capital Cost
Inside city
Outside city
City of Union Gap
Terrace Heights Service District
Septage Handling Facilities
Food process customers3
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Table 12-2. Components of Sewer Charges'
Sewer Construction Capital Cost
Inside city
Outside city
City of Union Gap'
Debt Expense WWTP
Inside city
Outside city
City of Union Gap
Terrace Heights Service District
Septage Handling Facilities
Rehabilitation/Replacement of Sewer Collection System
Inside city
Outside city
City of Union Gap'
New Collection Sewers
Developers
Inside city (limited initial)
Outside city (recovered upon connection)
1 Interceptor sewers downstream of connections with the City system.
2. Includes capital expenditures for food processing system and sprayfield areas.
3 During the winter months.
• 12.4 Utility Rates
•
The City of Yakima provides wastewater service to customers both inside and outside the
City limits and to the City of Union Gap, Terrace Heights Sewer District, and the
industrial waste system. As of 1996, approximately 21,600 retail accounts were served
by the retail system both inside and outside of the City of Yakima. Additionally, the City
of Union Gap served 1,250 retail customers, and Terrace Heights served 1,500 retail
customers. Septage disposal is provided at the Yakima Regional WWTP, and fruit waste
discharged by food process customers of the City are processed through a separate
pumping station and sprayfield.
12.4.1 Utility Rates Outside the City Limits
The City of Yakima has had an extensive history of the extension of City utility services
outside its corporate boundaries. Early City policy (1965-1968) encouraged annexation
to the City. It was recognized that some areas could not be annexed and fringe
development occurred without proper planning controls. In 1968, a resolution passed by
the City of Yakima stated that property owners requesting utility services outside the City
limits conform to the City General Plan and development codes.
In 1974, the City, County, Union Gap, and Terrace Heights signed the Agreement for
Wastewater Treatment and Disposal Service which granted the City responsibility for
providing wastewater service to an area many times larger than had been previously
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served. In 1976, an Urban Area Agreement was adopted that defined the obligations of
the City and established the direction for an annexation plan, which recognized the
provision of utility services to residents outside the City limits.
12.4.1.1 Policy on Yakima Retail Customers
The City of Yakima's 1990 report, along with the County's 1991 report, defined the basis
of the sewer service rates for customers. With their adoption, the utility basis of
accounting, discussed below, was chosen to calculate the costs of providing service to
retail customers outside of the City. When the costs of service are defined using the
utility basis of accounting for customers outside of the City, the remaining customers of
the utility system contribute the remaining cash requirements of the operation.
12.4.1.2 Cash and Utility Basis of Accounting
The cash basis of accounting calculates the revenue requirement of a utility on the basis
of cash receipts and cash outlays as they fall due. The four pnmary elements of cash
basis accounting are:
➢ Operating Expense — Operating expenses are the costs of operating the wastewater
system on a day-to-day basis, and include costs of operating and maintaining the
wastewater treatment plant, collection, and disposal facilities of the wastewater
treatment system, administrative costs, and system replacement costs.
➢ Debt Service — Debt service consists of payments of principal and interest on short
and long term financing incurred by the wastewater 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 — Consists of taxes paid to governing agencies, such as property taxes,
gross receipt taxes, franchise, or other types of taxes. Taxes are typically
categonzed under operating expenses.
The utility basis of accounting calculates the revenue requirement using different cost
elements than the cash basis. Depreciation expense and a rate of return allowance replace
debt service and cash outlays. Depreciation expense is a substitution for the principal
payments made by a utility under the cash basis. The rate of return allowance is used to
pay the utility and its owners for the interest costs on its debt, provide compensation for
equity payments that the utility uses to purchase capital equipment or facilities needed,
and provide an allowance for dividend payments to be made to its owners for nsking
capital. The three elements of the utility basis of accounting are:
• ➢ Operating Expense — Operating expenses are the costs of operating the wastewater
system on a day-to-day basis, and include costs of operating and maintaining the
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wastewater treatment plant, and collection and disposal facilities of the
wastewater treatment system, administrative costs, and system replacement costs.
➢ Depreciation Expense — The AWWA Manual M1 on Water Rates defines
depreciation expense as "The annual depreciation expense 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 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."
➢ Rate of Return Allowance (Return on Investment) — The AWWA Manual M1 on
Water Rates defines the rate of return allowance as "The return component is
intended to pay the annual interest cost of debt capital and provide a fair rate of
return for the total equity capital employed to finance physical facilities used to
provide utility service.
The utility approach of determining revenue requirements requires the establishment of a
rate base, defined to be the value of the assets on which the utility is entitled to earn a
return, and the fixing of a fair rate of return on the rate base. The rate base is primarily
composed of the value of the utility's plant and property useful in serving the public. In
addition, it is proper to include an allowance in the rate base for material and supplies,
working capital, and construction work in progress. On the other hand, contributions in
aid of construction and customer advances for construction are generally deducted from
utility plant in service for rate -based determination."
The rate base is defined as the historical cost of investment in plant facilities less
accumulated depreciation, contributions in aid to construction, and grant funds. Setting a
rate of return for a utility involves consideration of the cost of outstanding debt, the
market rates for dividend payments, and the amount of cash paid capital required by the
utility to meet its equity or equity growth requirements.
12.4.2 Utility Rates Inside the City Limits
The City of Yakima sets revenue requirements using the cash basis inside the City limits.
The City subsequently deducts revenue expected from retail and septage customers in the
County computed using the utility basis, and subtracts the revenue anticipated from
wholesale municipal customers (Union Gap and Terrace Heights), wholesale food process
customers, strong waste customers, and connection charges from total revenue
requirements. The City of Yakima retail customers pay the remaining cash requirements.
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• 12.5 Summary of Facility Improvements
•
•
This section provides a summary of recommended improvements to the wastewater
facilities for the Yakima Regional WWTP and for the City of Yakima Wastewater
Collection System.
12.5.1 Wastewater Treatment
The Yakima Regional WWTP needs rehabilitation and expansion of many of its
treatment systems to maintain mandatory compliance with state and federal regulations.
Features of construction identified during the course of this study which include
mandatory safety, reliability, and improved process operation are identified in Table 12-4.
Mandatory facility improvement and expansion projects are identified in Table 12-5.
Each table incorporates three columns which identify the penod in which the
improvements would be made: 0-6 years; 7-12 years; and 13 to 20 years.
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Table 12-4. Wastewater Treatment Facility Ke v Features Projects
Improvement Facility Description
Number
Opinion of
Probable Cost
0-6
Year
7-12
Year
13-20
Year
FWWTP-1 Influent Building
$50,000
$50,000
FWWTP-2 Emergency Generator Overhaul (400 KW) /Replacement
$100,000
$100,000
FWWTP-3 Primary Clarifier Collector Mechanisms
$400,000
$200,000
$200,000
FWWTP-4A Primary Sludge Pumping Density and Flow Meters
$240,000
$240,000
FWWTP-4B Primary Sludge Pumping Lighting Replacement
$10,000
$10,000
FWWTP-5 Sludge Transfer Building Refurbishment
$100,000
$100,000
FWWTP-6 Replace Intermediate Grit Box Center Wall
$250,000
$250,000
FWWTP-7A Trickling Filter Door/Walkway Covers
$85,000
$85,000
FWWTP-7B Trickling Filter Mechanism
$782,500
$391,300
$391,200
FWWTP-7C Trickling Filter Clarifier Gates
$50,000
$50,000
FWWTP-7D Trickling Filter Clarifier Solids Removal System/Dewatering
$425,000
$425,000
FWWTP-8A Repair Existing Aeration Basin
$675,000
$675,000
FWWTP-8B Replace Blower VFD's
$490,000
$245,000
$245,000
FWWTP-8C Aeration Basin Diffusers Rehab
$50,000
$50,000
FWWTP-9A Refurbish Secondary Clarifier Bull -Gears
$120,000
$120,000
FWWTP-9B Replace Secondary Clarifier Exterior Launders
$257,000
$257,000
FWWTP-9C Replace Secondary Clarifier Skimmer Mechanism/Scum Box
$362,000
$362,000
FWWTP-10 Refurbish DAFT Air Compressors/Pipelines
$267,000
$267,000
FWWTP-11A Add Secondary Digester Recirculation Pumps
$203,000
$203,000
FWWTP-11 B Install Secondary Digester Gas Flare
$60,000
$60,000
FWWTP-12 Trickling Filter Evaluation
$50,000
$50,000
FWWTP-13 Field Test Oxygen Transfer Efficiency
$50,000
$50,000
FWWTP-14 Secondary Clarifier Evaluation
$50,000
$50,000
FWWTP-15 Miscellaneous Improvements'
$1,000,000
$200,000
$400,000
$400,000
Total WWTP Opinion of Probable Costs
$6,126,500
$3,112,300
$1,746,200
$1,268,000
1 Five projects at $200,000 each. See Section 5 and 6.
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FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
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Table 12-5. Wastewater Treatment Facility Improvement Projects
Improvement
Facility Description
Number
Opinion of
Probable
Cost
0-6
Year
7-12
Year
13-20
Year
WWTP-1 Septage Receiving Facility
$2,079,300
$2,079,300
WWTP-2 Grit Storage Hopper
$312,100
$100,000
212,100
WWTP-3 Primary Split Box
$870,500
$870,500
WWTP-4A Trickling Filter Media Replacement
$1,699,100
$1,699,100
WWTP-4B Trickling Filter Forced Ventilation
$1,066,100
$1,066,100
WWTP-5 New RAS/WAS Pumping Station
$1,669,400
$1,699,400
WWTP-6 New Secondary Clarifier
$3,277,800
$3,277,800
WWTP-7A Anoxic Selector Cells
$2,480,000
$2,480,000
WWTP-7B Aeration Basin (2.1 mg)
$7,629,100
$4,366,600
WWTP-7C Additional Blower
$547,800
$547,800
WWTP-8 UV Disinfection
$3,931,100
$3,931,100
WWTP-9 WAS Thickening
$1,338,600
$1,338,600
WWTP-10 Centrate Pretreatment
$1,912,700
$1,912,700
WWTP-11A Solids Building
$3,412,600
$3,412,600
WWTP-11B New Centrifuge
$1,589,100
$1,589,100
WWTP-11C Polymer System
$976,200
$976,200
WWTP-12 Laboratory Modifications
$1,000,000
$1,000,000
WWTP-13 Truck Storage
$400,000
$400,000
WWTP-14 New boiler/hot water
$150,000
$150,000
WWTP-15 Mesophilic Digestion
$4,000,000
$4,000,000
WWTP-16 Biosolids Handling
$3,638,400
$3,638,400
Total WWTP Opinion of Probable Costs
$40,717,400
$9,085,600
$24,134,200
$7,497,600
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CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
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• 12.5.2 Collection System
•
•
The City of Yakima Wastewater Collection system facility needs were identified in
Section 11. The existing system of trunk and interceptor sewers will be inadequate to
sustain the City's current level of service standards. Existing bottlenecks within the
collection system may create surcharging. The improvement program identified in Table
11-11 at a probable cost of $694,000 will provide replacement or parallel sewers to
correct existing system deficiencies. All improvements listed in Table 11-11 should be
completed dunng the 0-6 year time period. In addition, the development of a Collection
System Model at a probable cost of $120,000, and the implementation of a system
monitoring program at a probable cost of $120,000 are also considered to be pnonty
improvements for the Collection System and should be completed dunng the 0-6 year
time period. The expansion of the existing shop and administrative facilities at a
probable cost of $3,257,600 is considered to be a priority improvement during the 7-12
year time penod.
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. Table 11-13 identifies the opinion of
probable cost of Wastewater Collection System improvements at $1,867,000 to meet the
ultimate build -out conditions.
The opinion of probable cost in Table 11-13 ($1,867,000) represents the anticipated costs
of Wastewater Collection System improvements necessary to reach build -out conditions
within the Yakima Urban Area with the Rudkin Road Bypass alternative. The increase of
costs in the facility improvements to correct existing collection system bottlenecks (Table
11-11) to accommodate build -out flows in the Yakima Urban Area is $1,173,000. 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.
Table 11-14 identifies the opinion of probable cost of future trunk sewers and interceptor
sewers serving the Yakima Urban Area and the Urban Reserve Area. The total opinion of
probable costs for these improvements are shown as $27,111,900. Zone 2, the Yakima
Urban Area, has been assigned 30 percent of the improvement costs. Zone 3, the Yakima
Urban Reserve area, has been assigned 70 percent of the improvement costs.
Approximately 10 percent of these improvements are expected to be completed during
the 0-6 year time period; 40 percent during the 7-12 year time penod; and 40 percent
during the 13-20 year time penod.
The new interceptors serving the Urban Reserve Area will increase flows in the existing
collection system. Table 11-15 identified the opinion of probable cost of existing
Wastewater Collection System improvements necessary to reach build -out conditions
within the Yakima Urban Area and the Urban Reserve Area at $9,475,000. Of the total
opinion of probable cost in Table 11-15, $7,608,000 in increased cost is the direct result
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of the increase in Service Area. The assignment of probable cost to the Yakima Urban
Area (30 percent) is $2,842,400 and the assignment to the Yakima Urban Reserve area
(70 percent) is $6,632,600.
12.6 Projection of Facility Improvement
Projects Funded From Rate Revenues
The capital improvement projects presented in this Section are related to the
infrastructure of the wastewater utility. They are developed on an ongoing basis and are
generally divided into three types or categories, mandated improvements by federal
and/or state agencies; mandated improvements that are related to renewal and
replacement; and growth related facilities. Mandated projects are those which result from
new regulations of federal and/or state government and agencies. Mandated renewal and
replacement projects are the replacement of existing and worn out (depreciated) facilities
to comply with federal/state laws, rules, regulations, and requirements, or those projects
needed to meet current mandatory safety and reliability standards as required by the
federal/state government. Growth related facilities are those related to system expansion,
system upgrades, or new customers. Growth related facilities which are needed to meet
the provisions of the "Four Party Agreement" are considered to be mandatory.
Federal and/or state mandatory improvements require the development of new funding
sources, regardless of ability to pay. Although the federal and/or state regulatory agencies
sometimes provide partial funding for mandated improvements in the form of grants and
loans, those resources have been diminished dramatically over the last decade. As a
consequence, the City of Yakima and the Yakima Regional WWTP will be required to
use wholesale and retail rate revenues to pay a substantial portion (90 percent or more) of
the total costs either as cash or debt payments.
Present City policy states that funding for mandatory renewals and replacements should
be from retail rates. As a general financial "rule of thumb" the City of Yakima should be
funding mandatory renewals and replacements from rates at an amount greater than the
annual depreciation expense. Annual depreciation expense reflects the current
investment in the Yakima Regional WWTP and collection system that is being
depreciated. The wastewater treatment plant investment needs to be replaced in order to
maintain the existing level of infrastructure. The 1999 annual depreciation expense for
the Yakima Sewer Utility was approximately $2.9 M. Simply funding the annual
depreciation expense will not generate sufficient revenues to replace the existing or
depreciated facility. Consideration should be given to funding at rates greater than the
annual depreciation expense to fund renewals and replacements. It is recommended that
a funding level of 1.25 times annual depreciation expense be used for the rate funding of
mandatory renewal and replacement capital improvements.
Growth related facilities are generally funded with new financial resources generated
from property assessments, connection charges, and development fees. Federal and/or
state funding sources are often limited for new construction for growth related facilities.
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If available, funding sources are generally limited to replacement of existing
infrastructure, promotion of economic growth of the community, or for resolving a health
threat in the area to be served.
Earlier in this Section, recommended improvements at the Yakima Regional WWTP and
for the collection system were prioritized based on facility needs. This section ranks the
0-6 year, 7-12 year, and 13-20 year priority improvements based on whether the
improvements are "Mandatory" (mandated by federal/state regulations; mandated to meet
current and future health and safety regulation; mandated renewal, replacement,
rehabilitation, and operational issues; or mandated to meet the requirements of the "Four
Party Agreement"); or "Growth" (expansion to meet population growth and/or increasing
Service Area growth) related.
Table 12-6 shows all improvements (treatment and collection) previously listed with a 0-
6 year priority rating.
Table 12-6. 0-6 Year Priority Improvement Projects
Improvement
Number
Facility Description
Opinion of
Probable Cost
Mandatory'
Growth z
Regulations
Renewal/
Safety
FWWTP-2
FWWTP-3
FWWTP-4B
FWWTP-7A
FWWTP-7B
FWWTP-8A
I FWWTP-8B
FWWTP-8C
FWWTP-9A
FWWTP-9B
FWWTP-9C
FWWTP-10
FWWTP-12
FWWTP-13
FWWTP-14
FWWTP-15
Emergency Generator Overhaul/Replacement
Primary Clarifier Collection Mechanisms (2 of 4)
Primary Sludge Pumping Lighting Replacement
Trickling Filter Door/Walkway Covers
Trickling Filter Mechanism (1 of 2)
Repair Existing Aeration Basin
Replace Blower VFD's (2 of 4)
Aeration Basin Diffusers Rehab
Refurbish Secondary Clarifier Bull -Gears
Replace Secondary Clarifier Exterior Launders
Replace Secondary Clarifier Skimmer
Mechanism/Scum Box
Refurbish DAFT Air Compressors/Pipelines
Trickling Filter Evaluation
Field Test Oxygen Transfer Efficiency
Secondary Clarifier Evaluation
Miscellaneous Improvements
$100,000
$200,000
$10,000
$85,000
$391,300
$675,000
$245,000
$50,000
$120,000
$257,000
$362,000
$267,000
$50,000
$50,000
$50,000
$200,000
$675,000
$245,000
$50,000
$50,000
$50,000
$50,000
$100,000
$200,000
$10,000
$85,000
$391,300
$120,000
$257,000
$362,000
$267,000
$200,000
Subtotal FWWTP Improvements
$3,112,300
$1,120,000
$1,992,300
--
WWTP-2
WWTP-5
WWTP-6
WWTP-13
WWTP-16
Grit Storage Hopper
New RAS/WAS Pumping Station
New Secondary Clarifier
Truck Storage
Biosolids Handling
$100,000
$1,669,400
$3,277,800
$400,000
$3,638,400
$1,669,400
$3,277,800
$400,000
$3,638,400
$100,000
•
•
•
•
Subtotal WWTP Improvements
$9,085,600
$8,985,600
$100,000
--
TOTAL Treatment Plant Improvements
$12,197,900
$10,105,600
$2,092,300
--
Collection Model/Monitoring
Section 11
$240,000
$240,000
Collection Facility
Table 11-11
$694,000
$694,000
Collection Facility
Table 11-13 & 11-15
$1,173,000
$1,173,000
Collection Facility
Table 11-14 (20%)3
$5,422,400
$1,626,700
$3,795,700
Subtotal Collection Facility
$7,529,400
$1,866,700
$1,867,000
$3,795,700
TOTAL TREATMENT/COLLECTION
$19,727,300
$11,972,300
$3,959,300
$3,795,700
• Indicates secondary benefits to Growth related issues.
Compliance with federal/state laws and regulations, and the Four Party Agreement.
• 2Non-mandatory growth/system expansion.
330% to Mandatory, 70% to Growth
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Table 12-7 identifies all improvements (treatment and collection) previously listed with a
7-12 year prionty rating, and identifies whether the improvements are "Mandatory" or
"Growth" related.
Table 12-7. 7-12 Year Priority Improvement Projects
Improvement
Number
Facility Description
Opinion of
Probable Cost
Mandatory'
Regulations
Renewal/
Safety
Growth Z
FWWTP-1
Influent Building
$50,000
$50,000
FWWTP-3
Primary Clarifier Collection Mechanisms (2 of 4)
$200,000
$200,000
FWWTP-5
Sludge Transfer Building Refurbishment
$100,000
$100,000
FWWTP-6
Replace Intermediate Grit Box Center Wall
$250,000
$250,000
FWWTP-7B
Trickling Filter Mechanism (1 of 2)
$391,200
$391,200
FWWTP-7D
Trickling Filter Clarifier Gates
$50,000
$50,000
FWWTP-8B
Replace Blower VFD's (2 of 4)
$245,000
$245,000
FWWTP-1IB
Install Secondary Digester Gas Flare
$60,000
$60,000
FWWTP-15
Miscellaneous Improvements
$400,000
$200,000
$200,000
Subtotal FWWTP Improvements
$1,746,200
$200,000
$1,546,200
--
WWTP-2
Grit Storage Hopper
$212,100
$212,100
WWTP-4A
Trickling Filter Media Replacement
$1,699,100
$1,699,100
•
WWTP-4B
Trickling Filter Forced Ventilation
$1,066,100
$1,066,100
•
WWTP-7A
Anoxic Selector Cells
$2,480,000
$2,480,000
WWTP-7B
Aeration Basin (2.1 mg)
$4,366,600
$4,366,600
WWTP-8
UV Disinfection
$3,931,100
$3,931,100
•
WWTP-9
WAS Thickening
$1,338,600
$1,338,600
•
' WWTP-10
Centrate Pretreatment
$1,912,700
$1,912,700
•
WWTP-11A
Solids Building
$3,412,600
$3,412,600
•
WWTP-11B
New Centrifuge
$1,589,100
$1,589,100
•
WWTP-1IC
Polymer System
$976,200
$976,200
•
WWTP-12
Laboratory Modifications
$1,000,000
$1,000,000
•
WWTP-14
New Boiler/hot water
$150,000
$150,000
•
Subtotal WWTP Improvements
$24,134,200
$16,640,300
$3,127,300
$4,366,600
TOTAL Treatment Plant Improvements
$25,880,400
$16,840,300
$4,673,500
$4,366,600
Collection Facility
Table 11-15 (inc only)3
$7,608,000
$2,282,400
$5,325,600
Maintenance Bldg
Section 11
$3,257,600
$2,606,100
$651,500
Collection Facility
Table 11-14 (40%)3
$10,844,800
$3,253,400
$7,591,400
Subtotal Collection Facility
$21,710,400
$8,141,900
$13,568,500
TOTAL TREATMENT/COLLECTION
$47,590,800
$24,982,200
$4,673,500
$17,935,100
•
• Indicates secondary benefits to Growth related issues.
Compliance with federal/state laws and regulations, and the Four Party Agreement.
2Non-mandatory growth/system expansion.
330% to Mandatory, 70% to Growth
Table 12-8 shows those improvements (treatment and collection) identified as 13-20 year
priority rating together with identification as "Mandatory" or "Growth" related.
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE 14
DRAFT
Table 12-8. 13-20 Year Priority Improvement Projects
' Improvement
Number
Facility Description
Opinion of
Probable Cost
Mandatory'
Growth z
Regulations
Renewal/
Safety
FWWTP-4A
Primary Sludge Pumping Density and Flow
$240,000
$240,000
Meters
FWWTP-7D
Trickling Filter Clarifier Solids Removal
$425,000
$425,000
System/Dewatering
FWWTP-11 A
Add Secondary Digester Recirculation Pumps
$203,000
$203,000
FWWTP-15
Miscellaneous Improvements
$400,000
$400,000
Subtotal FWWTP Improvements
$1,268,000
$1,268,000
WWTP-1
Septage Receiving Facility
$2,079,300
$2,079,300
WWTP-3
Primary Split Box
$870,500
$870,500
•
WWTP-7C
Additional Blower
$547,800
$547,800
WWTP-I5
Mesophilic Digestion
$4,000,000
$4,000,000
Subtotal WWTP Improvements
$7,497,600
$2,079,300
$870,500
$4,547,800
TOTAL Treatment Plant Improvements
$8,765,600
$2,079,300
$2,138,500
$4,547,800
Collection Facility Table 11-14 (40%)3
$10,844,700
$3,253,400
$7,591,300
Subtotal Collection Facility
$10,844,700
$3,253,400
$7,591,300
TOTAL TREATMENT/COLLECTION
$19,610,300
$5,332,700
$2,138,500
$12,139,100
• Indicates secondary benefits to Growth related issues.
'Compliance with federal/state laws and regulations, and the Four Party Agreement.
2Non-mandatory growth/system expansion.
330% to Mandatory, 70% to Growth
Table 12-9 summarizes the total opinion of probable cost for wastewater treatment plant
and collection system costs over the next 20 years by the time penod for which they are
anticipated to occur.
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE 15
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DRIP
TABLE 12-9. SUMMARY OF IMPROVEMENTS
TREATMENT/
COLLECTION
OPINION OF
PROBABLE
COST
MANDATORYI.',
, .TOTA_I':':%, ,
,. -- ,.o
MANDATORY-';
2
GROWTH
TOTAL- %
GROWTH,
REGULATIONS
RENEWAL/SAFETY
Wastewater Treatment
0-6 Year Projects3
7-12 Year Projects
j
13-20 Year Projects
$12,197,900
$25,880,400
$8,765,600
$10,105,600
$16,840,300
$2,079,300
$2,092,300
$4,673,500
$2,138,500
_ 100.0 `:.::` "
t ._, 83:1;;,¢,°x,
.. ;#,,a;:48•1 : ,; .r`
----
$4,366,600
$4,547,800
s ` 0.0.',.
=16;.9
51.9
Total Treatment Plant
Improvements
$46,843,900
$29,025,200
$8,904,300
'= =v81.0 7
a� ?::"...:t�'M.°'4`iM sGE::ducti'l.•,
$8,914,400
19
Collection Facility
0-6 Year Projects3
7-12 Year Projects
13-20 Year projects
$7,529,400
$21,710,400
$10,844,700
$1,866,700
$8,141,900
$3,253,400
$1,867,000
----
---
am_=46 a<
' 7
- = : 30 0 =w ,'`: z-
$3,795,700
$13,568,500
$7,591,300
,K3x 2ti�'
4
"70 0 ;
Total Collection
FacilityImprovements
$40,084,500
$13,262,000
$1,867,000
37:7- :':� , , },,
$24,955,500
:;62.3...."r':;":~
3s
TOTAL
TREATMENT/
COLLECTION
$86,928,400
$42,287,200
$10,771,300
...dµ
61.0' rN
:..`:'.. ., ..,,, .
$33,869,90039:0;,''
``':....,.....
Mandatory compliance with federal/state laws and regulations, and the Four Party Agreement. Non -mandatory growth/system expansion receives a benefit from mandatory
projects.
2Non-mandatory growth/system expansion.
3For the 0-6 Year period, a total of $19,727,300 is required. $15,931,600, or 80.8 percent, is required to meet mandatory obligations. $3,795,700, or 19.2 percent, is required to
meet non -mandatory growth/system expansion.
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE 16
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DRAFT
During the next 6 years, the Yakima Regional WWTP must invest $12,197,900 in the
treatment facilities, 100 percent of which is required to meet mandatory regulatory
requirements, to maintain existing facilities, and to provide for mandatory system
expansion within the Service Area. Also during the next 6 years, the City of Yakima and
the development community must invest $7,529,400, 49.6 percent of which is required to
meet mandatory requirements, in extension of new interceptor and trunk sewers into
currently unsewered areas, and in replacement and/or parallel interceptor and trunk
sewers to accommodate the expanded Service Area.
Over the 20 -year period, the Yakima Regional WWTP must invest $46,843,900 in the
treatment facilities to meet mandatory regulatory requirements, to maintain existing
facilities, and to provide mandatory and non -mandatory system expansion for growth
within the Service Area. Dunng this same period, the City of Yakima and the
development community must invest $40,084,500 in extension of new interceptors and
trunk sewers into currently unsewered areas, and in replacement and/or parallel
interceptor and trunk sewers to accommodate the expanded Service Area. Also during
this penod, the development community and individual home owners will invest
approximately $80,000,000 to $100,000,000 in construction of collection system
pipelines of 10 -inches in diameter or less.
Of the total $86,928,400 in capital expenditures identified in this Mandatory Wastewater
Facilities Plan for wastewater treatment and collection system improvements,
$53,058,500 of these improvements are required to meet Mandatory laws and regulations
of state and federal agencies (both existing and future); Mandatory requirements for
compliance with NPDES permit conditions (renewal and renovation); and Mandatory
obligations to provide regional wastewater treatment and interceptor sewers to the
Yakima Area as defined in the "Four Party Agreement".
The remaining $33,869,900 in capital expenditures identified in the Mandatory
Wastewater Facilities Plan are for those improvements directly resulting from an increase
in the service area and an increase in the population to be served.
For those Mandatory Projects which result in benefits to Growth as indicated in Table 12-
6, 12-7, and 12-8, that portion of the total opinion of probable cost benefiting other
Growth has been identified in Table 12-10.
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE 17
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DRAFT
Table 12-10. Assignment of Probable Cost to Growth of the Service Area
Improvement
Number
Facility Description
Opinion of
Probable Cost
Mandatory
Growth
WWTP-3
Primary Split Box3
$870,500
$435,250
$435,250
WWTP-4A
Trickling Filter Media Replacement2
$1,699,100
$339,820
$1,359,280
WWTP-4B
Trickling Filter Forced Ventilation2
$1,066,100
$213,220
$852,880
WWTP-5
New RAS/WAS Pumping Station'
$1,669,400
$834,700
$834,700
WWTP-6
New Secondary Clarifier'
$3,277,800
$1,638,900
$1,638,900
WWTP-8
UV Disinfection2
$3,931,100
$3,144,880
$786,220
WWTP-9
WAS Thickening2
$1,338,600
$669,300
$669,300
WWTP-10
Centrate Pretreatment2
$1,912,700
$956,350
$956,350
WWTP-11A
Solids Building2
$3,412,600
$2,047,560
$1,365,040
WWTP-11B
New Centrifuge2
$1,589,100
$794,550
$794,550
WWTP-11C
Polymer Systeme
$976,200
$488,100
$488,100
WWTP-12
Laboratory Modifications2
$1,000,000
$700,000
$300,000
WWTP-13
Truck Storage'
$400,000
$100,000
$300,000
WWTP-14
New Boiler/hot water2
$150,000
$50,000
$100,000
WWTP-16
Biosolids Handling'
$3,638,400
$2,910,720
$727,680
TOTAL Assignment of Improvements
$26,931,600
$15,323,350
$11,608,250
0-6 Year Priority Improvements (Table 12-6)
27-12 Year Priority Improvements (Table 12-7)
313-20 Year priority Improvements (Table 12-8)
As identified in Table 12-10, in meeting the Mandatory requirements for the Yakima
Area, $11,608,250 in capital expenditures out of to total $26,931,600 will result in
benefits to the increased service area and increased population. A total of $3,501,280 in
capital expenditures of the total $12,197,900 in treatment plant improvements identified
in Table 12-6 provide benefits to the increased service area and increased population.
Table 12-11 allocates the total opinion of probable cost for wastewater treatment plant
and collection system costs over the next 20 years by Mandatory and Non -mandatory
growth/system expansion.
Table 12-11. Improvements by Mandatory and Non -mandatory Allocation
Treatment/Collection
Opinion of
Probable Cost
Mandatory
Non -mandatory
Wastewater Treatment
0-6 Year Projects
$12,197,900
$8,696,620
$3,501,280
7-12 Year Projects
$25,880,400
$13,842,080
$12,038,320
13-20 Year Projects
$8,765,600
$3,782,550
$4,983,050
Total Treatment Plant
Improvements
$46,843,900
$26,321,250
$20,522,650
Collection Facility
0-6 Year Projects
$7,529,400
$3,733,700
$3,795,700
7-12 Year Projects
$21,710,400
$8,141,900
$13,568,500
13-20 Year Projects
$10,844,700
$3,253,400
$7,591,300
Total Collection Facility
Improvements
$40,084,500
$15,129,000
$24,955,500
TOTAL
TREATMENT/COLLECTION
$86,928,400
$41,450,250
$45,478,150
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE 18
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DRAFT
Financial options available to the City of Yakima for financing both mandatory and non-
mandatory obligations for expansion and continued operations of the interceptors and
treatment facilities are currently being developed in a Cost -of -Service Study. The Cost -
of -Service Study will include capital costs, annual operations and maintenance expenses,
and staffing obligations.
12.7 Summary of Facility Improvement
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 WWTP and for
the City of Yakima Wastewater Collection System.
12.7.1 Wastewater Treatment Program
The Yakima Regional WWTP Program staffing and equipment needs will not be
significantly increased as the result of improvements identified in this Plan. The existing
treatment process systems will be increased in size to accommodate wastewater flows as
population increases throughout the service area. As new equipment and enlarged
treatment process systems are added additional maintenance staff may be required. Table
12-12 identifies the anticipated annual costs for the Yakima Regional WWTP.
Table 12-12. Mandatory Yakima Regional WWTP Program Staffing O&M1
Category
Program Administration
Engineering Support
Facility Operations/Biosolids
Facility Maintenance
Facility Laboratory
Food processing
Power/Water/Refuse/Chemicals
Machinery/Equipment
City Services/Ancillary Costs2
Total Future WWTP Staffing/Program
Includes WWTP, Rudkin Road, Food Processing, and Laboratory
2Customer services, administrative overhead, state and local fees, debt service, and other charges.
Staffing/Equipment
5 people/equipment
3 people/equipment
22 people/equipment
10 people/equipment
8 people/equipment
3 people/equipment
Annual Cost
$375,000
$225,000
$1,650,000
$750,000
$600,000
$225,000
$420,000
$100,000
$1,592,000
$5,937,000
12.7.2 Pretreatment/Strong Waste Program
The Yakima Pretreatment/Strong Waste Program staffing and equipment needs were
identified in Section 6. Table 12-13 identifies the annual cost for these needs.
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE 19
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DRAFT
Table 12-13. Mandatory Pretreatment/Strong
Category Staffing/Equipment
Waste Program Staffing O&M
Annual Cost
Administration
Permit Administration
Pretreatment Technicians
Administrative Assistant
Operating/Supplies
Machinery/Equipment
1 person/equipment
3/6 people/equipment
4/6 people/equipment
1 person/equipment
$75,000
$225,000/$450,000
$300,000/$450,000
$75,000
$165,000/$258,000
$50,000/$78,000
Total Future Pretreatment Staffing/Program
$890,000/$1,386,000
12.7.3 Collection System Program
The City of Yakima Wastewater Collection system mandatory operation and maintenance
needs were identified in Section 11 and are shown in Table 12-14.
Table 12-14. Mandatory Wastewater Collection System Program Staffing O&M1
Category Staffing/Equipment Annual Cost
Administration 2.0 people, equipment $150,000
Cleaning/Flushing 6 people, equipment $450,000
Television Inspection 3 people, equipment $225,000
Grouting Program 3 people, equipment $225,000
Pumping Station 2 people, equipment $150,000
Emergency Crew 5 people, equipment $375,000
Operating/Supplies -- $296,000
Machinery/Equipment $418,000
City Services/Ancillary Costs' $851,000
Total Future Wastewater Collection Staffing/Program $3,140,000
'Customer services, administrative overhead, state and local fees, debt service, and other charges.
12.7.4
Storm Drainage Program
The Yakima Storm Drainage Program staffing and equipment needs were identified in
Section 14. An expansion of the existing Storm Drainage program will be necessary to
meet the mandatory federal and state laws, rules, regulations, and requirements. Table
12-15 identifies the anticipated annual costs for the Storm Drainage Program.
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE 20
DRAFT
• Table 12-15. Mandatory Storm Drainage System Program Staffing O&M
•
•
Category
Staffing/Equipment Annual Cost
Public Education and Outreach
Illicit Discharge Detection and Elimination
Construction Site Runoff Control
Post -Construction Runoff Control
Pollution Prevention/Good Housekeeping
Program Administration
Storm Water Capital ($3 7M)
ESA Capital ($6 3M)
Machinery/Equipment
City Services/Ancillary Costs'
Total Future Stormwater Staffing/Program
'Customer services, administrative overhead, state and local fees, and other charges.
1 person/equipment $75,000
2.5 people/equipment
1.5 people/equipment
1 person/equipment
9 people FT, 4 people PT,
equipment
2 people/equipment
$187,500
$112,500
$75,000
$725,000
$150,000
$370,000
$630,000
$275,000
$780,000
$3,380,000
12.8 Other Funding Sources
12.8.1 Environmental Protection Agency (EPA)
The Federal Water Pollution Control Act as amended (commonly referred to as the Clean
Water Act) was reauthorized by Congress in 1987. The amended Act, now known as the
Water Quality Act of 1987, removes uncertainties regarding funding. The act contains
provisions that will have a significant impact on financing the construction of wastewater
treatment facilities.
Nationally, $18 billion was authorized for financing facilities for federal fiscal years 1986
to 1994 and subsequently federal financing was terminated. The Federal Water Pollution
Control Act contains provisions for federal capitalization grants to states to establish state
revolving fund programs. Federal funding for construction grants was allowed until 1990
and funds provided from 1991 to 1994 were for capitalization grants to state revolving
funds. The State of Washington's allowance for this program is approximately $42
million per year.
12.8.2 Washington Department of Ecology
The State of Washington offers a variety of water quality grants and loan programs
administered by the Washington Department of Ecology (WDOE). The largest and most
flexible programs designed to finance wastewater treatment facilities and collection
systems are:
➢ The Centennial Clean Water Fund Program
➢ The Washington State Water Pollution Control Revolving Fund Program
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE 21
DRAFT
• The Centennial Clean Water Fund Program
•
•
In 1986, the Washington State Legislature established the Water Quality Account, which
funds a vanety of programs related to water quality. This account is financed primanly
from tabacco tax revenue and may also be supplemented from the State General Fund,
subject to legislative appropriation. The Centennial Clean Water Fund (Centennial) is
one of the programs funded by the account, and is authonzed by Chapter 70.146 of the
Revised Code of Washington (RCW). The Centennial fund provides grants and low
interest loans to local governments and Indian tribes for water pollution control facilities
and water pollution control activities designed to prevent and control water pollution to
the state's surface and ground water. The Water Quality Program of the WDOE has
administered the Centennial fund since its inception.
The Washington State Legislature has directed that the Centennial fund will be used to
finance the planning, implementation, design, acquisition, construction, and improvement
of water pollution control facilities and water pollution control related activities. It is
WDOE's goal to assure that the fund is distributed among projects that address the state's
highest prionty water quality protection and water pollution control needs.
Funding Allocations
The Washington State Legislature simplified the structure of the Centennial funding
allocations in their 1997 session, creating just two categories. WDOE has been directed
to emphasize implementation activities (greater than or equal to 80 percent of the funds
offered) over planning activities (no more than 20 percent of the funds).
To ensure that the fund is distributed fairly, WDOE has placed limits on the number and
size of grants and loans available for each public body for each fiscal year. Each public
body is limited to a maximum of five new funded projects from the Centennial program
and the Section 319 program (meant for projects that improve and protect the state's
water quality such as the implementation of stream and habitat restoration and stormwater
pollution control), two of which may be facility projects.
Ceiling amounts have been set for Centennial grant and loan participation per project and
are listed below.
➢ For facility projects, the total amount of Centennial grant and loan assistance
cannot exceed $2.5 million per annual funding cycle.
➢ For activity projects, the total amount of Centennial grant and loan assistance
cannot exceed $250,000 per annual funding cycle.
A local match of 50 percent of total eligible costs must be provided for water pollution
control facility grants. A local match of 25 percent of total eligible costs must be
provided for water pollution control activity grants.
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLF_MYIENTATION - OCTOBER 25, 2000
PAGE 22
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DRAFT
If a public body has received full funding for a project as a loan from the SRF or other
state or federal funding program, and the loan agreement has been signed, that project is
considered to have been previously funded and therefore ineligible for Centennial
funding. An exception is allowed if the loan terms of the other funding program have not
adjusted residential user charges to 1.5 percent of the median household income, and if
the grant funding is necessary to meet or reduce the financial hardship on the recipient.
12.8.2.1 The Washington State Water Pollution Control
Revolving Fund Program
The Washington State Water Pollution Control Revolving Fund (SRF) provides low
interest loans to local governments for projects that improve and protect the state's water
quality. The United States Congress established the SRF program as part of the Clean
Water Act (CWA) Amendments of 1987. The amendments authorized the U.S.
Environmental Protection Agency (EPA) to offer annual capitalization grants to states for
establishing self-sustaining loan programs. In response, the Washington State Legislature
passed a statute in 1988 (Chapter 90.50A RCW, Water Pollution Control Facilities —
Federal Capitalization Grants) which created Washington State's SRF Program. Funding
for Washington's SRF Program includes federal grants and a 20 percent state match
composed of Water Quality Account Funds. Funding will typically also include capital
from loan principal and interest repayment.
The Washington State Water Pollution Control Revolving Fund Program provides low-
cost financing or refinancing of eligible costs for projects, including publicly owned
wastewater treatment facilities, nonpoint source pollution control projects, and
comprehensive estuary conservation and management programs.
Funding Allocations
Chapter 173-98 of the Washington Administrative Code (WAC), Uses and Limitations of
the Water Pollution Control Revolving Fund, requires WDOE to distnbute money
according to the following category allocations:
> Eighty percent of the fund is to be used for water pollution control facilities.
> Ten percent of the fund is reserved for nonpoint source pollution control.
> Ten percent is allocated for comprehensive estuary conservation and management.
Unless the demand for funds is limited, no more than 50 percent of each funding category
allocation can be awarded to any one applicant. In addition, if requests for SRF
assistance in one category do not result in the offer of all available funds, any remaining
funds are transferred to other categories. Loans are provided for up to 100 percent of the
total eligible project cost.
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE 23
DRAFT
• 12.8.3 Public Works Trust Fund
•
•
This low interest revolving loan fund is administered by the Washington Department of
Community, Trade, and Economic Development to help finance critical public works
needs. Eligible projects include loans for repair, replacement, and improvements to
wastewater facilities. The Public Works Trust Fund (PWTF) provides funding for
improvements to existing facilities only. However, the program can consider funding of
new conveyance facilities (up to private property lines) since such a new wastewater
system would be considered a replacement of existing onsite septic systems. A maximum
of $10.0 million is allowable per biennium per jurisdiction.
Loan interest rates depend on the level of local participation (percent matching funds, not
including other state or federal funding). The following interest rates apply: 2 percent
with 5 percent match (minimum); 1 percent with 10 percent match; and 1/2 percent with
15 percent or more match. The repayment period is 20 years for a standard PWTF loan.
12.8.4 Community Economic Revitalization Board
The Washington Department of Community, Trade, and Economic Development's
Community Revitalization Board (CERB) provides low interest loans and occasional
grants to cities, counties, and special purpose districts for finance of public facilities such
as sewers that will lead to direct economical development gain, job creation; and new
business or industrial expansion. Average grants/loans of $3,000 per job created have
been awarded in past years. CERB policy limits the maximum amount available for any
one project to $750,000.
While the City would be the local government applicant, the intent of CERB is to meet
the needs of the manufacturing economic sector only. A new or expanding
manufacturing business must require the infrastructure to maintain or create jobs.
CERB loan interest rates fluctuate with the state 20 -year bond rate and may not exceed
the statutory 10 percent rate ceiling. CERB may grant a lesser rate if they agree that an
applicant's justification of such need is valid. A local match of 10 percent of the CERB
request demonstrated as in-kind contribution or cash is required. Preliminary engineering
drawings, cost estimates, and specific new employment projections resulting from
infrastructure improvements are required. Convincing evidence that a private sector
development is ready to occur must also be submitted with the application. The
application period is year round.
12.8.5 Economic Development Administration (EDA)
EDA provides loans and grants for projects that will ultimately provide additional jobs
for increased employment of the area. To support the City's position in regard to EDA
grants, the applicant should obtain a commitment from a manufacturer or interested
industrial concern that they wish to be located or expand within the Yaluma Urban Area.
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE 24
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DRAFT
This letter of commitment would support the application for assistance to the EDA.
Grants from EDA range from a minimum of 50 percent to a maximum 90 percent of a
project and generally fall between $1.0 million and $2.0 million in grant funds depending
upon economic conditions in the area.
12.8.6 Public Works Timber Trust
The Washington Department of Community, Trade and Economic Development's Public
Works Timber Trust Fund provides low interest loans to communities for new or
expanded infrastructure to support local economic diversification. Industrial,
commercial, and tourism projects that will result in the broadening of the local tax base
and the creation of jobs for displaced timber workers are eligible.
Loans for $1.5 million (maximum) with 0 to 3 percent interest are available. The first 5
years of principal payments for the 20 year term loan may be deferred. A local match is
not required although applicants are encouraged to access other funding resources as
leverage.
12.8.7 Block Grant — General Purpose
Grants to cities or counties for water pollution control, drinking water, roads, streets, and
bridge projects are available from the Washington Department of Community, Trade, and
Economic Development from this program.
Approximately $8 million is available each year with the maximum grant amount for
each project of $500,000. Only one application for each funding cycle by each applicant
is permitted by the agency.
HDR ENGINEERING, INC.
CITY OF YAKIMA
FINANCIAL PLANNING/IMPLEMENTATION - OCTOBER 25, 2000
PAGE 25