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WASTE DISCHARGE REQUIREMENTS ORDER NO. 98-217 • COUNTY OF SAN JOAQUIN -2- COUNTY SERVICE AREA NO. 31 FLAG CITY WASTEWATER TREATMENT AND DISPOSAL FACILITY SAN JOAQUIN COUNTY 6. The wastewater treatment and disposal facilities consist of a continuousflow n extended aeratio activated sludge process with daily hand skimming, clarification in a"clarator"unit, and sand filtration before disposal to the 2.24 million gallon EP pond. 7. Waste activated sludge solids are stabilized by aerobic digestion, then dewatered in a"Draimad" unit, which introduces an organic polymer to the solids as they are deposited into hanging porous plastic bags. The filtrate that drains from the biosolids is returned to the headworks. The bagged solids are further dried by air, then stacked in a covered metal storage unit. Ultimate disposal after testing is by landfilling. 8. San Joaquin CSA No. 31 operates two water supply wells in the general vicinity of the wastewater treatment plant. Well No. 2, which is the lead well, is 1170 feet from the southwest corner of the EP pond. Well No. I is the lag well, and it switches on only in the rare event of equipment failure and a subsequent pressure drop in the system. Well No. I is 210 feet from the southwest comer of the pond. Both wells are designed essentially the same. The sanitary seals are 87 feet deep beginning at the surface. Fifty feet of louvered casing is installed between elevations 110 and 160 feet below the ground surface. 9. Since the beginning of April 1998, the Discharger, with Board staff concurrence, stopped chlorination and dechlorination of treated effluent, as required under the current permit. Given the silty clay soils underlying the EP pond, the depth of the sanitary seals of the water wells, and the fact that the closer supply well is only a backup well,pathogen contamination from the EP pond should not be a problem. Also, monthly bacteriological testing of the water supply is done in accordance with the requirements of the Department of Health Services. Cessation of chlorination and dechlorination should minimize the formation of disinfection byproducts such as trihalomethanes and haloacetic acids and should also result in lower total dissolved solids in the discharge. 10. The Flag City wastewater treatment plant is exempt from coverage under the NPDES General Permit for Discharges of Storm Water Associated with Industrial Activity, because wastewater flows are less than one mgd. 11. The Board adopted a Water Quality Control Plan, Fourth Edition, for the Sacramento River and San Joaquin River Basins (hereafter Basin Plan), which contains water quality objectives for all waters of the Basin. These requirements implement the Basin Plan. 12. The beneficial uses of White Slough are municipal and agricultural supply; recreation; esthetic enjoyment; groundwater recharge; fresh water replenishment; and preservation and enhancement of fish, wildlife, and other aquatic resources. 13. The beneficial uses of underlying groundwater are domestic, industrial, and agricultural supply. 14. The action to adopt waste discharge requirements for this facility is exempt from the provisions of the California Environmental Quality Act (CEQA), in accordance with Title 14, California Code of Regulations (CCR), Section 15301.