ARCHIVED REPORTS_XR0009622 - Laserfiche WebLink

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V � F • Thrifty Oil Co. Station #172 Page3 In addition, vapor samples were collected on February 11, 2003 from selected well heads The well head, influent, and effluent vapor samples were analyzed for TPH-g by EPA method 8015, and BTEX/MTBE by EPA method 8021B Copies of the influent, effluent, and wellhead vapor sample laboratory analytical results are presented in Appendix D The effluent air sample results are within the San Joaquin Valley Air Pollution Control District requirements A historical summary of hydrocarbons removed by vapor extraction is presented in Table 3, vapor sample analytical results for the individual wells sampling are presented in Table 5 The Field Status Reports are included in Appendix C Groundwater Treatment System The groundwater treatment system was started in conjunction with the vapor treatment system on April 26, 2001, and the flow meter started at zero Presently, the remediation system is connected to groundwater wells MW-10 and MW-11 Two down-well pneumatic pumps (one in each well) draw water into a 150-gallon polyvinyl tank, which then transfers the water through two (2) one thousand-pound canisters with activated carbon . During this reporting period, the groundwater extraction system was down for repairs The operation of the groundwater system was resumed on April 9, 2003 after installation of a continuous LEL monitoring device that is interlocked with the control circuit of the groundwater pumping system, meeting the City of Stockton, Department of Municipal Utilities (CSDMU) new permit requirements As of June 27, 2002, a total of 93,114 gallons had been treated and discharged Historical groundwater system operations are reported in Table 4 Summary and Recommendations The soil vapor and groundwater extraction systems were started on April 26, 2001 A total of 64,292 pounds of hydrocarbons have been destroyed by the vapor extraction system, and 93,114 gallons of groundwater have been treated by the groundwater system The groundwater extraction system was non-operational throughout the quarter,because of system maintenance and new permit requirements from the CSDMU Thnfty believes that the contamination found in well MW-6 is either from cross-contamination during gauging and sampling or from an independent off-site source Thrifty will take extra precautions to avoid any possible cross-contamination during the next sampling event If the contamination is still found within the well during the next sampling event, it 1s a reasonable possibility that it is from another off-site source, because Thnfty has a non-detect well (MW-3) • between the on-site and off-site contamination