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Introduction Beyond the Phase III expansion,the City has identified the need to plan for future facilities to
<br /> accommodate growth contained in its General Plan(City of Manteca,2003),which plans growth
<br /> PROJECT LOCATION AND BACKGROUND out until 2023. As such,the City has prepared its Wastewater Quality Control Facility Master
<br /> Plan Update(Nolte,2007). This master plan update considers the necessary treatment facilities
<br /> The City of Manteca's Wastewater Quality Control Facility(WQCF)is located at the northern to accommodate up to 27 MGD(ADWF),which will accommodate growth out until 2023.
<br /> end of the San Joaquin Valley of Central California approximately 75 miles east of San
<br /> Francisco and 55 miles south of Sacramento. The WQCF is located approximately 1.5 miles PROJECT DESCRIPTION
<br /> west of the City of Manteca(City)in southern San Joaquin County. The WQCF has expanded The City is proposing to increase the permitted wastewater discharge capacity of the WQCF
<br /> several rimes since operations began in 1959. From 1986—1988,a major expansion to the plant from 9.87 MGD(ADWF)to 27 MGD(ADWF)and construct new trunk sewers to accommodate
<br /> known as Phase I was constructed. The Phase I expansion project included the construction of growth planned in the City's General Plan(City of Manteca,2003). The project includes
<br /> secondary treatment facilities,anaerobic sludge digesters,sludge drying beds,a chlorine treatment plant improvements for both river and land-based wastewater effluent disposal based
<br /> disinfection system,and an outfall to the San Joaquin River at the point latitude 37°,46',45" on current and future probable water quality discharge requirements and projected flows.
<br /> (deg,min,sec)and longitude 121°,18',00"(deg,min,sec). The WQCF outfall is sited
<br /> approximately one mile upstream of the Mossdale Bridge which is located near the intersection The proposed project would include construction of treatment facilities to achieve compliance
<br /> of Interstate 5 and Highway 120. Design capacity of the plant following the Phase I project was with water quality objectives and permit requirements including rapid mixing and flocculation
<br /> 5.45 million gallons per day(MGD)average dry weather flow(ADWF). The Phase II expansion tanks to address turbidity requirements,and a tertiary UV light disinfection treatment system to
<br /> project constructed in 1992 and 1993 added a primary sedimentation basin,a secondary clarifier, address water reuse requirements. The proposed project would be initiated no sooner than 2012,
<br /> and four sludge drying beds,increasing plant capacity to 6.95 MGD(ADWF). and would reach build-out via a two-phase,incremental expansion with capacity increasing from
<br /> 9.87 MGD(ADWF)to 17.5 MGD(ADWF)in the first phase(Phase IV)and then from 17.5
<br /> In 1995,the City adopted a Wastewater Quality Control Facility Master Plan that identified MGD(ADWF)to 27 MGD(ADWF)in the second phase(Phase V). The City proposes to
<br /> Phase III improvements. The Phase III improvements included the construction of nitrification- accommodate the increase in capacity by using the City's long-term effluent disposal strategy
<br /> denitrification facilities(increasing plant capacity from 6.95 MGD to 7.5 MGD(ADWF)), that includes land application,urban landscape irrigation,and river discharge. The proposed
<br /> improved primary and secondary treatment facilities(increasing capacity from 7.5 MGD to 9.87 project would also include the incremental construction of three new trunk sewers and
<br /> MGD(ADWF)),and solids handling,tertiary filtration and ultraviolet(UV)disinfection improvements to the existing collection system.
<br /> facilities(Nolte,1995). The City has divided Phase III improvements into four schedules:A,B,
<br /> C,and D. PURPOSE OF REPORT
<br /> Schedule A and B improvements have been completed. Schedule A improvements included two The purpose of this report is to document the City's antidegradation analysis for a projected
<br /> new aeration basins,three modified secondary clarifier sludge collection mechanisms,two new discharge increase in permitted discharge capacity to the San Joaquin River from 9.87 MGD
<br /> centrifugal blowers,and a skid-mounted centrifugal dewatering system. Schedule B (ADWF)to 27 MGD(ADWF). The information contained in this analysis is intended to provide
<br /> improvements included a new influent pump station,two aerated grit tanks,three primary the Regional Water Resources Control Board(Regional Water Board)with the information
<br /> sedimentation basins,five aeration basins,two secondary clarifiers,an odor control biofilter,and needed to determine whether to certify that the proposed permitted discharge increase is
<br /> an expanded laboratory and administration building. consistent with State and Federal antidegradation policies.
<br /> Schedule C improvements,which are scheduled to begin construction in October 2007,include a APPROACH TO ANALYSIS
<br /> sludge control building,a mechanical dewatering facility,and a shop maintenance building.
<br /> Schedule D improvements are currently being constructed at the WQCF. Schedule D The antidegradation analysis described in this report follows the guidance provided by the State
<br /> improvements include a secondary effluent equalization pond,a filter feed pump station, Water Resources Control Board(State Water Board)regarding the implementation of the
<br /> coagulation and flocculation facilities,tertiary filters,a chemical storage and handling facility,a antidegradation policy in NPDES permits(APU 90-004). Pursuant to the guidelines,this
<br /> UV disinfection system,an effluent pumping station,two odor control biofilters,recycled water analysis follows the provisions for a`complete analysis'and evaluates whether changes in water
<br /> pumping stations,a groundwater well,and a construction truck recycled water filling station. quality resulting from the proposed capacity increase are`consistent with maximum benefit to
<br /> Schedule D improvements will allow for the off-line storage and timed discharge of treated the people of the state,will not unreasonably affect uses and will not cause water quality to be
<br /> effluent to the San Joaquin River. Schedule D improvements are anticipated to be constructed less than water quality objectives and that the discharge provides protection for existing in-
<br /> and operational by August 2007,while Schedule C improvements are anticipated to be stream uses and water quality necessary to protect those uses.
<br /> constructed and operational by October 2008. It is anticipated that Phase III improvements The complete analysis is comprised of two main components:(1)a comparison of the projected
<br /> would satisfy the City's wastewater treatment capacity demands for the next 5—10 years receiving water quality to the water quality objectives and/or criteria used to protect designated
<br /> depending on the build-out rate of proposed development. beneficial uses,and(2)a socio-economic analysis to establish the balance between the proposed
<br /> action and the public interest.
<br /> City of Manteca Antidegradation Analysis I June 2007 City of Manteca Antidegradation Analysis 2 June 2007
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