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Stockton Regional Wastewater-wntrol Facility " 26 July 2001 Inspection Report The Operator Certificates were current and displayed in the administration building. Mr. Anderson explained that there were 18 operators employed with the City to operate and maintain the Regional Wastewater Control Facility, 12 for the Secondary Plant and 6 for the Tertiary Plant. This number is significantly reduced from previous years. It is our understanding the City has reduced its staff in an effort to reduce overall costs. The City should report on staffing level changes and its impact on plant operations and maintenance. INSPECTION OF TERTIARY PLANT: We concluded our inspection of the Secondary Plant and drove to the Tertiary Plant. Mr. Mark Von Aspern,Tertiary Plant Operations Supervisor,joined Mr. Anderson in conducting the tour of the Tertiary Plant. Secondary effluent is pumped under the San Joaquin River to the Tertiary Plant,which is located on the west side of the river. We inspected the oxidation ponds, dissolved air flotation(DAF)units, filtration units, and chlorination/dechlorination process. All facilities were in operation and the City was discharging to the San Joaquin River at a rate of 24.7 million gallons per day. No obvious violations were noted during the inspection of the Tertiary Plant. The City was performing a pilot study on the DAF units to determine the effectiveness of polymer in the removal of algae sludge. One of the DAF units was used for the study. The DAF unit utilizing polymer was producing a good floc and there was very little foaming. The City is considering using polymer to provide a better removal of algae sludge and to promote algae growth in the oxidation ponds. The algae are required to reduce the ammonia. Alum,which is currently being used, can inhibit the growth of algae. The City was adding anhydrous ammonia to the wastewater prior to chlorination to increase the oxidizing effects of chlorine,creating chloramines. This was being done because the oxidation ponds are very effective in reducing ammonia during the summer months. Mr.Von Aspern said they were adding 2 mg/L of ammonia-N to the wastewater. RWQCB SAMPLING AND ANALYSIS: To supplement the inspection, RWQCB staff collected water samples of the effluent and submitted these samples for independent analytical testing. In addition,readings from online analyzers at the facility were recorded during the inspection. The results of the field tests and online analyzers are summarized in Table 1. Table I. Effluent Samples Online Analyzers Parameter Value Parameter Value TSS 5.0 mg/L Flow 24.7 mgd CBOD 1.4 mg/L Temperature 28.7°C Ammonia-N 8.3 mg/L pH 6.58 Settleable Solids <0.1 ml/L Turbidity 4.437 ntu Cyanide <0.005 mg/L Alkalinity 144 mg/L Hardness 177 mg/L Total Coliform <2 mpn/100 ml Oil&Grease <5.0 mg/L Copper 4.2 µg/L Lead 1 <3.0 2