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California Regional Water Quality Control Board s Central Valley Region Steven T.Butler, Chair W on H.Hickox Gray Davis cretaryfor Sacramento Main Office 13 Governor c,rvir•onmental Internet Address: http://www.swrcb.ca.gov/—iwgcb5 Protection 3443 Routier Road,Suite A,Sacramento,California 95827-3003 Phone(916)255-3000•FAX(916)255-3015 28 November 2000 Ken Price Glenn Springs Holdings,Inc. 2480 Fortune Dr., Suite 300 Lexington,KY 40509 TENTATIVE WASTE DISCHARGE REQUIREMENTS, TECHNOLOGIC AND ECONOMIC FEASIBILITY STUDY, FORMER OCCIDENTAL CHEMICAL SITE—LATHROP, CA, Case #4397 We have reviewed the Tentative Waste Discharge Requirements, Technologic and Economic Feasibility Study(TE Report), dated 14 November 2000, as prepared by CRA, Inc., for the former Occidental Chemical site (OCC). The Board requested a TE study be performed to verify whether indeed the current system could be optimized to meet the proposed water quality goals as daily maximum and monthly average concentrations for DBCP, EDB, and sulfolane. OCC also included in the report alternative treatment technologies and associated costs. Based on our review, we find that the report is incomplete with regards to providing the necessary details required to adequately review the technologic and economic options discussed. Our comments follow: 2.1.3 Technology Effectiveness The document states that the proposed WDRs limits are clearly below levels that the current system is capable of achieving. It is not clear from the data(Table 2)when the system was pulsed nor does the TE Report discuss operational optimization of the system to achieve the lower limits. It appears that the system was run the most efficiently in 1998 rather than 1997 or 2000 based upon monitoring results. For instance, Table 2, DBCP 1998 data shows a 0.03 ppb hit on 1/19/98 and then was consistently at ND (0.01 ppb) for nine consecutive sampling events. A result of 0.02 was recorded on 3/30/98 with five subsequent higher concentrations over the next month's sampling events. It appears that the system was not pulsed and the concentrations were allowed to increase over time. What criteria are considered prior to pulsing the system? How many more times would the existing system be pulsed to achieve the lower limits? What modifications in the operations of the system can be made to enhance contaminant removal consistently at the proposed levels in the Tentative WDRs? What alternative carbon sources were considered, what are the associated costs per pound of carbon, and what are the costs of additional operator time to pulse the system more efficiently? OCC should provide details in a subsequent TE Study that addresses these concerns. Potential modifications/additions to the existing GAC system were evaluated to assess the possibility of meeting the proposed WDR criterion. These modifications/additions included changing the flow characteristics of the system(e.g., downflow vs. upflow), the addition of more carbon beds, and the use of alternative carbon sources. It is stated that extensive pilot and field-testing would be needed to assess if this is doable on a consistent bases. We concur that a study might show that the proposed limits in the WDRs are not consistently achievable, but a value below Maximum Contaminant Levels (MCLS) is reasonable. Requirements may be written to allow for a pilot study period where interim limits are set pending results of the study. This interim period would allow OCC to not only modify or add to the system, but also change operations in order to maximize treatment. Furthermore,the current system is approximately 18 years old California Environmental Protection Agency ca Recycled Paper