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Occidental Chemical Corpor^'�on <br /> Summary 2006 Annual Revi, Meeting Minutes <br /> and Semi-Annual Report <br /> Lathrop, CA - 3 - 23 October 2006 <br /> maximum of 57 ug/L based on practical quantitation limits (PQLs) and Department of <br /> Health Services' guidance, respectively. <br /> After review of the tentative WDRs, MSRM stated in the April 2006 meeting that they <br /> could not consistently meet the proposed new discharge limits for EDB, DBCP and <br /> sulfolane with the existing system. MSRM said that this issue was addressed in their <br /> Containment Zone Application (CZA) and Technological and Economic Feasibility <br /> Study (TEFS), prepared in 2000. The CZA and TEFS concluded that the existing <br /> groundwater treatment system could not consistently meet the proposed new discharge <br /> limits for EDB, DBCP and sulfolane based on historical system performance and <br /> system modification would be too costly to implement. In the April 2006 meeting, <br /> Regional Board staff said that they would revisit the CZA application and the TEFS, and <br /> evaluate the findings to determine if anything could be done to improve the treatment <br /> efficiency of the system. <br /> Based on our review of the CZA and TEFS, it appears that achieving effluent limits of <br /> 0.01 ug/L, 0.01 ug/L, and 20 ug/L for DBCP, EDB and sulfolane, respectively, are <br /> technologically problematic with the current system and use of other evaluated <br /> technologies (i.e. chemical oxidation, resin beds, air strippers, etc.) are cost prohibitive. <br /> Though the TEFS ruled out several technologies, including the addition of-three <br /> "polishing" GAC vessels, the Regional Water Board staff believes that the system lacks <br /> redundancy or supplemental treatment. Given sulfolane and fumigant effluent <br /> exceedances above the original waste discharge requirements (WDRs) have been <br /> reported in the recent past, these exceedances confirm the need for supplemental <br /> treatment of the effluent. In an effort to comply with industry standards and apply the <br /> best available treatment technology, at a minimum, the Regional Water Board staff <br /> requests MSRM to consider adding at least one "polishing" GAC vessel or similar <br /> technology to each treatment stream (two total). Even though there may be an initial <br /> installation cost and slight increases in maintenance and analytical costs, operational <br /> costs may decrease due to the ability of the system to more effectively use the leading <br /> GAC beds to their fullest extent prior to change-out. Therefore, the Regional Water <br /> Board staff requests MSRM to prepare a supplemental treatment work plan (STWP) <br /> that proposes supplemental treatment of the current system's effluent stream. <br /> If the Regional Water Board staff approves the STWP and the system modifications are <br /> subsequently implemented, the Regional Water Board staff will revise the WDRs with <br /> the consideration that best available technology has been implemented. The discharge <br /> limits for EDB, DBCP and sulfolane may then be set at those levels at which the <br /> modified system will be capable of achieving in the treated discharge stream. <br /> 5. Regional Water Board staff discussed its concerns with the sulfolane exceedances in <br /> the remedial system effluent and asked why these exceedances occurred. MSRM <br /> stated that the air injection set-up that they had been using was dependent upon the <br /> continued system operation from J.R. Simplot's facility operations, which unknowingly <br /> to MSRM had been shut off over certain weekends. Since these incidents, MSRM has <br /> reconfigured the compressed air lines for the air injection system to avoid the <br /> unanticipated air injection shutdowns and has stated that during the summer of 2006, <br />