SITE INFORMATION AND CORRESPONDENCE 1980-1999

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to the Regional Board. The Discharger should be required to continue sampling until analytical results reveal no further violations. This sample methodology of requiring repeated sampling and analysis when repeated violations are detected has been used in industrial NPDES permits and pretreatment programs across the county. If violations are revealed,the additional sampling will establish the magnitude and extent of the excursion. When the sampling establishes compliance, no further sampling is needed. We note that the Tentative Permit specifies that standard minerals samples be collected by a grab sample. It is more appropriate to use a 24-hour composite sample for these minerals. L. Temperature. The Discharger has a one-to-two to one-to-four dilution rate at R-2. Given the typical background temperature of domestic wastewater,the effluent is likely to have an impact on the receiving waters during the late fall months. This is a critical period for dissolved oxygen. Elevated temperatures will aggravate the problem. As we have previously stated, a continuous reading temperature monitoring device should be required for Dredger Cut. VI. THE DISCHARGER'S LOCAL LIMITS ARE INADEQUATE. Federal regulations 40 CFR 403.5(d)requires the development of local limits when pass through or interference is noted at the POTW. The Regional Board has determined that there is a reasonable potential for water quality violations for zinc, lead and cyanide. The Discharger must develop local limits which will ensure that these violations will cease. The Regional Board needs to include a compliance order directing the development of local limits for these pollutants. We have noticed a trend toward reductions in pretreatment staffing levels throughout Region 5. The Regional Board should insert a provision into the permit that clarifies that any reduction in staffing for pretreatment programs is considered a significant change and subject to public comment. VII. THE TENTATIVE PERMIT FAILS TO DISCUSS TRIHALOMETHANES. The Discharger uses chlorine for disinfection. Trihalomethanes are a buy-product of chlorination and are generally found in POTW effluent,yet we can find no discussion concerning trihalomethanes. The Information Sheet should discuss whether trihalomethanes were present in the effluent,the concentrations found and the detection limits employed. DeltaKeeper,Tentative NPDES Permit,Lodi, 17 December 1999,Page 15.