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REGIONAL BOARD RESPONSE (SWRCB/OCC FILE A-1483) -13- PETITION FOR REVIEW OF WASTE DISCHARGE REQUIREMENTS ORDER NOS. R5-2002-0083 AND R5-2002-0084 CITY OF STOCKTON REGIONAL WASTEWATER CONTROL FACILITY The Regional Board considered the factors specified in CWC section 13263, including considering the provisions of Water Code section 13241, in adopting the disinfection requirements under Title 22 criteria. Cost information provided by the Discharger regarding upgrades to meet Title 22 specifications are estimated to be $6.6 million in construction costs and approximately$3.4 million more per year in operation and maintenance costs for flows of 42 mgd at the plants. For flows of 55 mgd, the maximum allowed by Order R5-2002-0083, the estimated construction costs are projected at $14.6 million and the annual operation and maintenance cost is projected at$4.44 million. The Regional Board found, on balance, these requirements are necessary to protect the beneficial uses of the SJR, including body contact water recreation and irrigation uses. Order R5-2002-0083 provides interim limitations for total coliform of 23 MPN/100 ml as a monthly median and 240 MPN/100 ml as a daily maximum, which the Discharger is currently capable of meeting. Full compliance with the turbidity and the 2.2 MPN/100 ml total coliform limitations are not required until 1 May 2006. In the mean time, Stockton is required to maximize use of the existing tertiary treatment facilities, which were previously only operated during peak algal producing periods (July—October). Adequate time is provided for the Discharger to propose alternatives that are still protective of public health and irrigation uses but at a reduced cost. FOURTH BASIS: EFFLUENT LIMITATIONS BASED ON UNADOPTED CRITERIA Stockton requests that the State Board direct the Regional Board to modify the effluent limitations for chlorine, pH, mercury, chloroform, diazinon, lindane, endrin aldehyde, DDT, and copper, and make modifications to the findings and conclusions. "66. In Order R5-2002-0083, the RWQCB imposed end-of-pipe effluent limitations for several constituents based on the finding that the receiving water or downstream water bodies are listed on the state's Clean Water Act 303(d) list as impaired for these constituents and that there is no assimilative capacity for these constituents. Constituents with the effluent limitations based on 303(d) listing include diazinon, lindane, endrin aldehyde,DDT, and mercury. "67. The RWQCB failed to explain in the Permit the basis for the 303(d) listing and failed to provide evidence to support that there is no assimilative capacity for the listed constituents in the vicinity of the discharge." The Regional Board did explain the basis for the 303(d) listing and provided evidence that there is no assimilative capacity for the constituents. The basis for the 303(d) listing of mercury, dioxin/furans, PCBs, and Group A organo-chlorine pesticides is discussed in Order R5-2002-0083 in the Fact Sheet, Section 11.1, "Mercury, dioxinlfurans, PCBs, and Group A organo-chlorine pesticides, which include lindane, endrin aldehyde, and DDT, are California 303(d) listed pollutants causing impairment in Delta waterways. This listing is based on the fact that these pollutants bioaccumulate in aquatic organisms and the environment. " Evidence is discussed below. In addition, there are other bases for making the reasonable potential conclusion in addition to the 303(d) listing of the SJR. s The RWCF has a secondary treatment capacity of 42 mgd.