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WASTE DISCHARGE REQUIREMENTS ORDER NO.R5-2004-0028 -23- WASTE DISCHARGE REQUIREMENTS ORDER NO.R5-2004-0028 -24-
<br /> CITY OF MANTECA,CITY OF LATHROP AND DUTRA FARMS CITY OF MANTECA,CITY OF LATHROP AND DUTRA FARMS
<br /> WASTEWATER QUALITY CONTROL FACILITY WASTEWATER QUALITY CONTROL FACILITY
<br /> SAN JOAQUIN COUNTY SAN JOAQUIN COUNTY
<br /> DISSOLVED OXYGEN ISSUES To protect these beneficial uses,the Regional Board finds that the wastewater must be
<br /> disinfected and adequately treated to prevent disease. The principal infectious agents
<br /> 55. The dissolved oxygen(DO)objectives applicable to the San Joaquin River are as follows: (pathogens)that may be present in raw sewage may be classified into three broad groups:
<br /> bacteria,parasites,and viruses. Tertiary treatment,consisting of chemical coagulation,
<br /> a. The Basin Plan prescribes a minimum DO concentration in the San Joaquin River of 5.0 sedimentation,and filtration,has been found to remove approximately 99.5%of viruses.
<br /> mg/l. This standard is applicable throughout the year. Filtration is an effective means of reducing viruses and parasites from the waste stream.
<br /> Filtration is also necessary prior to UV disinfection to prevent any solids from interfering with
<br /> b. The Bay/Delta Plan prescribes a minimum DO concentration of 6.0 mg/1 in the San Joaquin the performance of the UV disinfection system. The wastewater must be treated to tertiary
<br /> River inside the reach from Turner Cut to Stockton during the period 1 September through standards(filtered)to protect contact recreation and food crop irrigation uses and to assure the
<br /> 30 November. This higher DO concentration was imposed to enhance aquatic conditions reliability and effectiveness of UV disinfection.
<br /> during critical migration periods for salmon.
<br /> The California Department of Health Services(DHS)has developed reclamation criteria,CCR,
<br /> 56. The DO objectives are frequently not met in the San Joaquin River,leading to the Clean Water Title 22,Division 4,Chapter 3(Title 22),for the reuse of wastewater. Title 22 requires that for
<br /> Act section 303(d)listing.In 1998,the Regional Board classified the DO impairment within the spray irrigation of food crops,parks,playgrounds,schoolyards,and other areas of similar public
<br /> San Joaquin River as a Toxic Hot Spot,making it a high priority problem for correction. Since access,wastewater be adequately disinfected,oxidized,coagulated,clarified,and filtered,and
<br /> the spring of 1999,the Discharger and other stakeholders have participated in the steering that the effluent total coliform levels not exceed 2.2 MPN/100 ml as a 7-day median. Title 22 is
<br /> committee for the development of the DO TMDL for the San Joaquin River in the Deep Water not directly applicable to surface waters;however,the Regional Board finds that it is appropriate
<br /> Ship Channel(DWSC). A TMDL implementation plan was submitted to the Regional Board in to apply DHS'reclamation criteria because the San Joaquin River is used for irrigation of
<br /> February 2003.Staff has developed and submitted to the USEPA in June 2003 a TMDL report agricultural land and for contact recreational purposes. The stringent disinfection criteria of
<br /> for controlling the problem. The existing low DO conditions in the Stockton DWSC are Title 22 are appropriate since the relatively undiluted effluent may be used for the irrigation of
<br /> partially the result of channel morphology,and point and non-point sources that are beyond the food crops. Coliform organisms are intended as an indicator of the effectiveness of the entire
<br /> control of the Discharger. The Discharger will make a significant reduction in the magnitude of treatment train and the effectiveness of removing other pathogens. The method of treatment is
<br /> its contribution to the DO problem by implementation of more stringent ammonia and BOD not prescribed by this Order;however,wastewater must be treated to a level equivalent to that
<br /> effluent limitations through the construction of nitrification,denitrification,and tertiary recommended by DHS.
<br /> coagulation and filtration facilities. These facilities will prevent ammonia toxicity and reduce
<br /> the nitrogenous and carbonaceous biochemical oxygen demand that is presently exerted on the In addition to coliform testing,a turbidity effluent limitation has been included as a second
<br /> San Joaquin River. indicator of the effectiveness of the treatment process and to assure compliance with the required
<br /> level of treatment. The tertiary treatment process,or equivalent,is capable of reliably meeting a
<br /> Based on the above information,further action by the Discharger to reduce its impact on the San turbidity limitation of 2 nephelometric turbidity units(NTU)as a daily average. Failure of the
<br /> Joaquin River DO concentration,beyond the requirements of this permit,will not be required by filtration system such that virus removal is impaired would normally result in increased particles
<br /> the Regional Board until such time as the TMDL for DO has been developed and approved by in the effluent,which would result in higher effluent turbidity. Turbidity has a major advantage
<br /> USEPA. This Order contains a provision to allow for the permit to be reopened to consider for monitoring filter performance,allowing immediate detection of filter failure and rapid
<br /> modification of effluent limitations after the DO TMDL is finalized. corrective action. Coliform testing,by comparison,is not conducted continuously and requires
<br /> several hours,to days,to identify high coliform concentrations.
<br /> DISINFECTION/FILTRATION
<br /> The establishment of tertiary limitations has not been previously required for this discharge;
<br /> 57. The beneficial uses of the San Joaquin River include municipal supply,water contact therefore,a schedule for compliance with the tertiary treatment requirements is included as a
<br /> recreational uses and agricultural irrigation supply,and there is,at times,less than 20:1 dilution. Provision in this Order. This Order provides interim effluent limitations for BOD,TSS,and
<br /> Recreational uses identified in the immediate vicinity of the WQCF outfall include boating, total coliform,which the Discharger is currently capable of meeting. Full compliance with the
<br /> skiing,swimming,and fishing. A number of agricultural diversions have been identified through final effluent limitations for BOD,TSS,total coliform,and turbidity are not required by this
<br /> a search of the State Board,Water Rights Division database. Within an approximate one-mile Order until completion of tertiary treatment facilities,or 1 February 2009,whichever is first.
<br /> radius of the outfall,there are approximately five agricultural diversions identified in the Adequate time is provided for the Discharger to propose alternatives that are still protective of
<br /> database. One of the agricultural diversions is just downstream and in the immediate vicinity of public health and irrigation uses,but at a reduced cost. The permit may be reopened at such time
<br /> the outfall. as the Discharger proposes an alternative that is protective of public health and irrigation uses.
<br /> Alternatives to tertiary treatment,such as expanded land disposal,would require modification of
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