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IVURLEY COOLING TOWER CPANNY • 11 <br /> GROUNDWATER EXTRACTION AND TREATMENT SYSTEM <br /> SAN JOAQUIN COLNTY <br /> RESPONSE TO COMMENTS <br /> 30 January 2003 <br /> average effluent limitation, imposition o=he new monthly average effluent limitation <br /> for total dissolved solids will likely require fundamental changes to the treatment <br /> process. This reconsideration of the treaunent processes, evaluation of alternatives, <br /> and eventual funding and implementation of a process which can comply with the <br /> new monthly average effluent limitation will require significant time. Provision G.3. <br /> of the TO requires submission of a workplan, and semi-annual progress reports as a <br /> means of charting progress toward compliance with the new limitation. <br /> 5. Comment: Finding No. 20 states that ";ojrder No. 93-221 included a daily <br /> maximum limitation for hexavalent chromium of II ug/1 (ppb) and a monthly average <br /> limitation of ll ug/l (ppb). " The Permi:contains new limits of 8 ug/1 (monthly) and <br /> 16 ug/1 (daily maximum). The new daily maximum limit of 16 ug/1 backslides from <br /> the previous limit of 11 ug/7. The federal regulations explicitly prohibit limits in a <br /> renewed permit that are less stringent than the previous permit. 40 CFR <br /> 122.44(1)(1). <br /> Response: Existing Order No. 93-221 provides no information on the reasonable <br /> potential analysis or justification of the water quality based permit effluent limitations <br /> for hexavalent chromium. Application of an identical effluent limitation as a monthly <br /> average and daily maximum appears to represent a technical oversight or mistaken <br /> interpretation of water quality standards. A new reasonable potential analysis was <br /> conducted using representative effluent data, the CTR and NTR, and procedures <br /> specified by the SIP. This representative effluent data may not have been available <br /> during the development of Order No. 93-2211. Based upon this current reasonable <br /> potential analysis, effluent limitations w e-e subsequently established for hexavalent <br /> chromium in accordance with procedures specified by the SIP. According to the SIP, <br /> the daily maximum effluent limitation in the TO is protective of water quality. <br /> Additionally, the new monthly average eluent limitation results in a significant <br /> reduction in overall allowable pollutant loading. <br /> 6. Comment: On 19 September 2002, Deltakeeper staff responded to a reported fish <br /> kill in the Stockton Diverting Canal. Confirming the presence of thousands of dead <br /> fish, Deltakeeper contacted the California Department of Fish and Game and the <br /> Office of Emergency Services. lnvesng_- on identified the Marley Cooling outfall as <br /> the likely source of the toxic discharge. while the investigation is continuing, it is <br /> apparent that the facility lacks sufficient alarms, redundancy of automatic shut-down <br /> and adequate employee training regarding spill notification requirements. These <br /> issues, as well as any other concerns d?scovered during the investigation, should be <br /> addressed in an accompanying enforcement order. <br /> Response: Comment noted. The noted:'ems will be addressed in an enforcement <br /> order. <br />