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WASTE DISCHARGE REQUIREMENTS 2 <br /> COUNTY OF SAN JOAQUIN <br /> COUNTY SERVICE AREA NO. 31 <br /> FLAG CITY WASTEWATER TREATMENT FACILITY <br /> SAN JOAQUIN COUNTY <br /> 5. The Discharger discharges an average of 0.0145 mgd of treated wastewater to the EP pond. <br /> 6. The wastewater treatment and disposal facilities consist of a continuous flow extended aeration <br /> activated sludge process with daily hand skimming, clarification in a"clarator" unit, and sand <br /> filtration before disposal to the 2.24 million gallon EP pond. <br /> 7. Waste activated sludge solids are stabilized by aerobic digestion, then dewatered in a <br /> "Draimad" unit, which introduces an organic polymer to the solids as they are deposited into <br /> hanging porous plastic bags. The filtrate that drains from the biosolids is returned to the <br /> headworks. The bagged solids are further dried by air, then stacked in a covered metal storage <br /> unit. Ultimate disposal after testing is by landfilling. <br /> 8. San Joaquin CSA No. 31 operates two water supply wells in the general vicinity of the <br /> wastewater treatment plant. Well No. 2, which is the lead well, is 1170 feet from the southwest <br /> corner of the EP pond. Well No. 1 is the lag well, and it switches on only in the rare event of <br /> equipment failure and a subsequent pressure drop in the system. Well No. 1 is 210 feet from <br /> the southwest corner of the pond. Both wells are designed essentially the same. The sanitary <br /> seals are 87 feet deep beginning at the surface. Fifty feet of louvered casing is installed <br /> between elevations 110 and 160 feet below the ground surface. <br /> 9. Since the beginning of April 1998, the Discharger, with Board staff concurrence, stopped <br /> chlorination and dechlorination of treated effluent, as required under the current permit. Given <br /> the silty clay soils underlying the EP pond,the depth of the sanitary seals of the water wells, <br /> and the fact that the closer supply well is only a backup well,pathogen contamination from the <br /> EP pond should not be a problem. Also, monthly bacteriological testing of the water supply is <br /> done in accordance with the requirements of the Department of Health Services. Cessation of <br /> chlorination and dechlorination should minimize the formation of disinfection byproducts such <br /> as trihalomethanes and haloacetic acids and should also result in lower total dissolved solids in <br /> the discharge. <br /> 10. The Flag City wastewater treatment plant is exempt from coverage under the NPDES General <br /> Permit for Discharges of Storm Water Associated with Industrial Activity, because wastewater <br /> flows are less than one mgd. <br /> 11. The Board adopted a Water Quality Control Plan, Third Edition, for the Sacramento River and <br /> San Joaquin River Basins (hereafter Basin Plan), which contains water quality objectives for all <br /> waters of the Basin. These requirements implement the Basin Plan. <br /> 12. The beneficial uses of White Slough are municipal and agricultural supply; recreation; esthetic <br /> enjoyment; groundwater recharge; fresh water replenishment; and preservation and <br />