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REGIONAL BOARD RESPONSE (SYI7ZCB/0CC FILE A-1483) 1 S- PETITION FOR REVIEW OF WASTE DISCHARGE REQUIREMENTS ORDER NOS. R5-2002-0083 AND R5-2002-0084 CITY OF STOCKTON REGIONAL WASTEWATER CONTROL FACILITY "79. The RWQCB further acted arbitrarily and unreasonable in applying the Basin Plan's narrative water quality objective for lindane rather than the more specific numeric objective found in the CTA." When setting effluent limitations, it is necessary to evaluate all water quality objectives and use the most stringent to protect the beneficial uses. The Basin Plan pesticide objective is more stringent than the CTR numeric criterion for lindane. The CTR and the SIP specify that the Regional Board should apply the Basin Plan water quality objective if it is more stringent than the CTR. Therefore, the Basin Plan objective must be applied. "80. The permit contains inappropriate effluent limitations for chlorine, based on EPA guidance. The RWQCB failed to consider the impact of chlorine decay/complexing, ignored pertinent technical information, and imposed a chlorine limit that is not necessary for the protection of beneficial uses. The chlorine limitation is inconsistent with the Basin Plan and adopted without compliance with Porter-Cologne, CEQA, and the APA." Chlorine is used as a disinfectant at the RWCF and is known to cause toxicity to aquatic organisms. Based on the effectiveness of dechlorination, chlorine may, at times, be present in the effluent. Thus, there is a reasonable potential that the discharge will cause or contribute to an excursion above the narrative toxicity objective. The previous NPDES permit, WDR Order No. 94-324, included a daily average limitation of 0.018 mg/l and a monthly average limitation of 0.011 mg/l, which were intended to address short-duration chlorine discharges. Stockton believes these effluent limitations are protective. However, the chorine residual limitations in Order No. 94-324 were based on receiving water studies performed by the Sacramento Regional County Sanitation District for its discharge into the Sacramento River, because Stockton had not yet performed similar studies. The USGS SJR flow gauge at Stockton has since been installed and much more information is now available regarding the Stockton discharge conditions. The tidal conditions in the SJR at Stockton are vastly different than in the Sacramento River in the vicinity of the Sacramento Regional discharge. The federal regulations at 40 CFR section 122.44(d)(1)(vi)(B), requires the state to establish effluent limitations to implement narrative objectives using one or more of several options, including using USEPA's water quality criteria. Order R5-2002-0083 establishes effluent limitations of residual chlorine consistent with the USEPA Ambient Water Quality Criteria for the Protection of Fresh Water Aquatic Life, 1984 (EPA 44015-84-030), 0.02 mg/1 as a one-hour average and 0.01 mg/1 as a 4-day average. This strict application of the water quality criteria is necessary because of periods of little or no dilution in the receiving.water. Continuous residual chlorine monitoring is currently in place at the RWCF and the facility is capable of meeting the new limitations. Additionally,based on State Board Resolution 68-16 ("Statement of Policy with Respect to Maintaining High Quality of Waters in California") and the federal antidegradation policy, 40 CFR 131.12, the City must, among other requirements,use best practicable treatment and control technology. In this case, implementation of best practicable treatment or control, which is already in place, achieves compliance with the effluent limitations. "81. The Permit includes effluent limitations for pH based on short-term flow conditions. The pH effluent limitation is inconsistent with the Basin Plan's use of thirty-day average flow conditions and