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RECEIVED <br /> Appendix A - Site Background Information 2016 <br /> Page 5 of 5 <br /> ENVIRONMENTAL <br /> HEALTH DEPARTMENT <br /> 5.0. GROUND WATER REMEDIATION RESULTS <br /> Between January 2002 and December 2007, ground water P&T remediation was <br /> performed at the site by extracting MTBE-impacted ground water from onsite, First Zone <br /> well EW-1; the extraction well was adjusted to continuously extract ground water at a flow <br /> rate of approximately 4 to 5 GPM. All extracted MTBE-impacted ground water was routed <br /> through a ground water treatment system consisting of four 2,000 pound media vessels <br /> containing coconut shell, liquid phase granular activated carbon (GAC). <br /> During the above referenced P&T operational period, a grand total of approximately <br /> 7,951,683 gallons of MTBE-impacted water was treated and discharged to the City of <br /> Manteca sanitary sewer system (located approximately 25 feet south of the remediation <br /> area) under City of Manteca Discharge permit no. 02-1. From the 7,951,683 gallons of <br /> treated ground water, a grand total of 308 pounds of MTBE was estimated to have been <br /> removed. <br /> During the ground water remediation pump-and-treat (P&T) operational period, EW-1 <br /> samples initially detected MTBE concentrations as high as 90,000 micrograms per liter <br /> (pg/1)in April 2002; however, MTBE concentrations from EW-1 generally decreased below <br /> 1,000 pg/I by December 2006, and were detected below 100 pg/I on eight separate <br /> occasions thereafter. <br /> Advanced GeoEnvironmental,Inc. <br />