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s <br /> F <br /> ENVIRONMENTAL HEALTIH DEPARTMENT <br /> SAN JOAQUIN COUNTY <br /> Unit Supervisors <br /> Donna K.Heran,R.E.H.S, Carl Borgsnan,R.E.H.S. <br /> 304 East Weber Avenue,Third Floor <br /> Director Mike Huggins,R.E.H.S.,RDI <br /> A]Olsen,R.E.H.S. Stockton,California 95202-2708 Douglas W.Wilson,R.E.H:S. <br /> .. Q I'rugrrltrr Managen Telephone: (209) 468-3420 Margaret Lagorio,R.E.KS. <br /> Laurie A.Cotulla,R.E.H.S. Robert McClellon,R.EM S. <br /> Nogram Manager FaX: -(}j,3 Mark Barcellos,R.E.H.S. <br /> COAR .l. u 2005 <br /> KASHMIR SINGH & DALWINAER DHOOT <br /> 15600 S HARLAN ROAD <br /> LATHROP CA 95330 <br /> RE: Joe's Place SITE CODE: 231585 <br /> 15600 Harlan Road <br /> Lathrop, Ca <br /> San Joaquin County Environmental Health Department(EHD) has reviewed the <br /> "Interim Remedial Action Pian" (IRAP) dated February 2, 2005, prepared by <br /> Stratus Environmental Inc. for the above referenced site. A Dual Phase <br /> Extraction (DPE)feasibility test was conducted on MW-7 in June 2004. during <br /> the test an average groundwater extraction rate of 7.2 gallons per minute was <br /> sustained. The average mass extraction rate for MTBE calculated in the "Dual <br /> Phase Extraction Test Report" was .008 pounds per day(4 grams per day), The <br /> IRAP used an estimation of mass flux to estimate the recoverable MTBE mass <br /> and rate of mass recovery using groundwater extraction. A mass recovery rate <br /> of 3.77 grams per day of MTBE when extracting groundwater at a rate of 7.5 <br /> gallons per minute was calculated. The IRAP proposes extracting groundwater <br /> from existing monitoring wells MW-2, MW-3 and MWO-1X. The cost for <br /> installation and one year of operation of a groundwater extraction and treatment <br /> system using the three existing wells was estimated to be $120,000. <br /> The 7.5 gallon per minute extraction rate is based on the DPE test that was <br /> conducted on extraction well MW-7 (4 inch diameter well). Monitoring wells MW- <br /> 2, MW3 and MW4-1X are 2-inch diameter wells. The sustainable extraction rate <br /> from these wells is unknown. <br /> Extraction well MW-7 does not appear to be properly located for optimizing <br /> contaminant mass capture as the MTBE concentration data suggests that this <br /> well is up to cross-gradient of the MTBE plume. Better results are likely to be <br /> -1X for groundwater extraction since they <br /> obtained using MW-2, MW-3 and MWO <br /> are located within the plume. <br /> EHD recommends that interim groundwater extraction from MW-2, MW-3 and <br /> MWO-1X be initiated through an extended pumping test to see if the MTBE <br /> concentrations will remain high enough to justify a continuous groundwater <br /> extraction system and to determine the optimum pumping rate. Once it is shown <br /> that a permanent interim system is justified, EHD will approve its installation. <br />