COMPLIANCE INFO_1990-1998 - Laserfiche WebLink

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WASTE DISCHARGE REQUIREMENTS CITY OF TRACY WASTEWATER TREATMENT PLANT SAN JOAQUIN COUNTY -4- 2. The arithmetic mean of 20°C BOD (5-day) and total suspended matter in effluent samples collected over a monthly period shall not exceed 15% of the arithmetic mean of the values for influent samples collected at approximately the same times during the same period (85% removal). 3. The discharge shall not have a pH less than 6.5 nor greater than 8.5. 4. The average dry weather discharge flow shall not exceed 9.0 mgd. 5. Survival of aquatic organisms in 96-hour bioassays of undiluted waste shall be no less than: Minimum for any one bioassay - - - - - - - - - - 70% Median for any three consecutive bioassays - - 90% 6. The maximum effluent temperature shall not exceed the natural receiving water by more than 20°F. C. Holding Ponds: 1. The dissolved oxygen content of holding ponds shall not be less than 1.0 mg/1 for 16 hours in any 24-hour period. 2. The holding ponds shall be designed, constructed, operated and maintained to prevent inundation or washout due to a storm event with a 100 year return frequency. 3. Ponds shall be managed to prevent breeding of mosquitoes. In particular, a. An erosion control program should assure that small coves and irregularities are not created around the perimeter of the water surface. b. Weeds shall be minimized through control of water depth, harvesting, or herbicides. c. Dead algae, vegetation, and debris shall not accumulate on the water surface. 4. Public contact with wastewater shall be precluded through such means as fences, signs, and other acceptable alternatives. 5. Percolation ponds shall have sufficient capacity to accommodate allowable wastewater flow and design seasonal precipitation and ancillary inflow and infiltration during the rainy season. Design seasonal precipitation shall be based on total annual precipitation using a return period of 100 years, distributed monthly in accordance with historical rainfall patterns. Freeboard shall never be less than two feet(measured vertically to the lowest point of overflow). 6. On or about 1 October of each year, available pond storage capacity shall at least equal the volume necessary to comply with Discharge Specification C.5. 7. Influent to the wastewater disposal ponds shall not cause the ponds to have a pH less than 6.5 or greater than 8.5.