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Stockton Regional Wastewater tbdtrol Facility *MW 26 July 2001 <br /> Inspection Report <br /> The ammonia-N test resulted in a concentration of 8.3 mg/L. This is the only test result that exceeded <br /> expected values. We understand anhydrous ammonia is being added to achieve better disinfection. <br /> However, the ammonia-N concentration is rather high. A review of the June 2001 SMRs also indicates <br /> high concentrations of effluent ammonia-N. On 21 March 2001, City staff notified the RWQCB of their <br /> plan to add ammonia in the tertiary treatment process to facilitate disinfection. The method of application <br /> and dosage rates were to be same as last year. However,the June 2001 monthly average effluent ammonia- <br /> N concentration(7.2 mg/L) is more than twice as high than the June 2000 average (3.0 mg/L). Also, the . <br /> June 2001 maximum effluent ammonia-N(14.9 mg/L)is more than 3 times the June 2000 maximum (4.5 <br /> mg/L). The City should report on the operating procedures for controlling the addition of anhydrous <br /> ammonia and explain the elevated concentrations of ammonia-N in the effluent. <br /> A review of the SMRs, from October 2000 through June 2001, indicates a violation of Water Reclamation <br /> Specification C.2,which states, "Reclaimed water shall be chlorinated secondary treated effluent. For <br /> adequate disinfection, the median number of coliform organisms in the water shall not exceed 23 MPN/100 <br /> mL, as determined from the bacteriological results of the last seven days for which analyses have been <br /> completed, and the number of coliform organisms shall not exceed 240 MPN/100mL in any 2 consecutive <br /> samples." The reclaimed water exceeded 240 MPN/100 mL total coliform in two consecutive samples on <br /> 17 April and 20 April 2001. <br /> CONCLUSION AND RECOMMENDATIONS: <br /> The secondary and tertiary treatment facilities appear to be operating well with no obvious violations noted <br /> during the inspection. Results of our independent sample collection and analyses revealed that the effluent <br /> was within the limits of the NPDES permit and waste discharge requirements at the time of sampling. <br /> However, our independent sampling and the review of the June 2001 SMRs indicated an elevated <br /> concentration of ammonia-N in the effluent. Therefore,we recommend the City report on the operating <br /> procedures for controlling the addition of anhydrous ammonia and explain the elevated concentrations of <br /> ammonia-N in the effluent. In addition,there have been significant reductions in staffing at the Regional <br /> Wastewater Control Facility in recent years. Therefore,we recommend the City report on staffing level <br /> changes and its impact on plant operations and maintenance. <br /> PHOTO LOG: <br /> See Appendix A <br /> Enclosure: Analytical Laboratory Reports <br /> Approved: IJAMS . MARSHALL, PE <br /> Wate esources Control Engineer <br /> 3 <br />