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City of Tracy -2- 8 July 1988 <br /> Mr. Scott stated H.J. Heinz constitutes 95% of the industrial flow. <br /> Another major industrial user (IU) , Leprino Cheese, discharges to <br /> aerated ponds located at the treatment plant for pretreatment. <br /> Currently, the IUs contribute approximately 30% of the average daily <br /> flow. <br /> After completing a plant tour, Darrell Scott and I went to the <br /> location where they are stockpiling the sludge in Pond #5. Mr Scott <br /> stated the City will not be able to continue stockpiling sludge in <br /> the oxidation pond and they need a decision from our office on final <br /> disposal for the sludge. I stated we had received their sludge <br /> sampling and management pian and we are reviewing it. We briefly <br /> discussed the issue of carbonaceous BOD (CBOD) versus total BOD <br /> (TBOD) analysis and I told Mr Scott that I would have to review the <br /> files before I could comment on both the CBOD versus TBOD study and <br /> the receiving water turbidity problem. <br /> f <br /> After reviewing the results of the 96-hour static bioassay test and <br /> receiving a draft report from the EPA on the pretreatment inspection <br /> conducted 16-19 May 1988 , we find that the City is consistently in <br /> violation of its' toxicity limits set in the NPDES permit: Less than <br /> 70% survival of test fish on eight occasions and the median of three <br /> consecutive test were less than 90% on eighteen occasions (see <br /> Attachment 1) . The list of bioassay results which show permit <br /> violations are inconsistent with the results reported to the RWQCB <br /> in the City's monthly Monitoring Reports. Apparently, the City's <br /> present practice is to consider a bioassay test invalid if the fish <br /> survival falls below 70%, and therefore report the result as 4 <br /> invalid. During the tine period in which the City has been r <br /> reporting invalid tests, the control test fish survival has been <br /> consistently 95% or 100% which does not make the tests invalid. We <br /> request that the City discontinue the practice of invalidating <br /> bioassay test and report results of all bioassay tests runs, <br /> regardless if they are considered invalid, and that the City <br /> investigate sources if the high biotoxicity in the effluent. <br /> Depending on where the plant effluent for the bioassay test is <br /> collected, potential sources of biotoxicity include chlorine <br /> residual or ammonia. After the source of toxicity has been <br /> identified, methods for its' elimination should be developed and <br /> implemented. <br /> I informed Mr. Scott that the WDRs require a certification <br /> signed by a California registered civil engineer, certifying that <br /> the plant is capable of meeting WDRs for flows up to 9 . 0 mgd. The <br /> expansion from 5. 5 mgd to 9 . 0 mgd was completed in March 1987 and no <br /> certification has been received by our office. Mr. Scott stated he <br /> was unaware that a certification was required or if it was <br /> completed. John Baker stated he would check to see if the <br /> certification had been completed. <br /> i <br /> t <br /> t <br /> i <br /> i <br />