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California Regional Water Quality <br />Central Valley Region <br />Winston H. Hickox <br />Secretaryfor <br />Environmental <br />Protection <br />16 September 2002 <br />Mr. Bob Cochran <br />Chevron Products Co. <br />PO Box 6004 <br />San Ramon, CA 94583 <br />Robert Schneider, Chair <br />Colitrol <br />_ RI <br />Board <br />f�EAl 711 <br />Sacramento Main Office �Lr 8 P <br />Internet Address: http://www.swrcb.ca.gov/rwgcb5 30 <br />3443 Routier Road, Suite A, Sacramento, California 95827-3003 <br />Phone (916) 255-3000 • FAX (916) 255-3015 <br />Ivern and Roger Baffoni <br />1175 Orangewood Drive <br />Lodi, CA 95240 <br />a <br />Gray Davis <br />Governor <br />REVIEW SECOND QUARTER 2002 PROGRESS REPORT, FORMER CIIEVRONSTA TION #9-5775, <br />301 WEST KETTLEMAN LANE, LODI, CLEANUP AND ABATEMENT (C&A) ORDER NO. 5-00-704 <br />Board staff reviewed the 15 July 2002 Quarterly Progress Report, Second Quarter 2002 (2Q02 Report) <br />submitted by Secor International Incorporated (Secor) for the former Chevron Station #9-5775 (Chevron). The <br />2Q02 Report documents decreasing trends of petroleum hydrocarbon and MtBE constituents in on-site <br />monitoring and extraction wells due to continued remedial activities at the site. Concentrations of petroleum <br />hydrocarbons and MtBE have decreased significantly since the soil vapor extraction (SVE) and groundwater <br />extraction and treatment (GET) systems began operation in July 2000. As of December 2001, 6.6 million <br />gallons of contaminated groundwater from the former Chevron site has been extracted, treated with carbon, and <br />discharged to the City of Lodi industrial sewer line. The average treatment system influent MtBE concentration <br />has stabilized at 84 micrograms per liter (µg/1). <br />The SVE mass removal rate for MtBE has decreased to zero pounds per day. Based on this data, Secor <br />recommends pulsing the SVE system on a quarterly basis, and suggests shutting off the SVE system for the <br />fourth quarter of 2002, and then restarting it in January 2003. Shutting off the SVE system for three months <br />seems excessive; however, due to the influent air concentrations at zero pounds per day, Secor's <br />recommendations are appropriate, and therefore approved. <br />We would like to reiterate that the focus of further remedial activities at this site should be directed at the high <br />concentrations of contaminants consistently identified in extraction well EX -l. (The maximum concentration of <br />MtBE remains at extraction well EX -1 at 15,000 µg/1.) Prior to issuing a no further action required letter for this <br />site, groundwater concentrations in all monitoring and remedial wells will need to show decreasing trends toward <br />meeting water quality objectives within a reasonable time. Therefore, if contaminant concentrations in <br />groundwater continue to stay elevated, it will be necessary to evaluate modifications to the remedial system (e.g. <br />adding SVE or groundwater extraction wells), or evaluate alternate technologies (e.g. air / ozone sparging, etc.). <br />If modifications or alternate technologies will increase the technical and economic feasibility of continued <br />remediation in a cost effective manner, then these modifications or enhancements should be made to the system. <br />California Environmental Protection Agency <br />Z�aRecycled Paper <br />The energy challenge facing California is real. Every Californian needs to take immediate action to reduce energy consumption. <br />For a list of simple ways you can reduce demand and cut your energy costs, see our Web -site at http://www.swrcb.ca.gov/rwgcb5 <br />