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I ' 28 October 2005 . AGE-NC Project No 95-0130 ' Page 8 of 13 ' 41 GROUND WATER EXTRACTION-TREATMENT OPERATION During the second quarter 2005, extraction wells EW-I and EW-2 were each adjusted at the well- heads to continuously extract ground water at a combined flow rate of approximately 2 to 3 gallons per minute(GPM),however, due to ground water draw-down issues at EW-1 and EW-2, an electric timer was installed to cycle EW-1 and EW-2 on and off at approximate 1-hour intervals ' During the second quarter, all extracted ground water was routed from the extraction wells to a 5,000-gallon holding tank,from the holding tank,water was treated by passing through a low profile ' air stripper,then through four 2,000 pound media vessels containing liquid phase granular activated carbon (GAC) Following treatment, water was discharged underground via I-inch diameter PVC piping to the City of Stockton sewer system, discharge piping is connected to a sewer clean-out ' located in a east section of the site, approximately 100 feet east-northeast of the pump-and-treat system Between 08 March 2005 and 03 June 2005, the extraction and treatment interim ground water remediation system (P+T)was in operation for approximately 87 days A Blue-White Industries F- 2000 flow meter on the P+T treatment system recorded approximately 148,180 gallons of water • extracted, treated and then discharged to the City of Stockton sewer system under City of Stockton Department of Utilities Ground Water Discharge Permit (dated 1 i August 2003), AGE estimated that an average 1,703 gallons of water was discharged per day during this time I 42 GROUND WATER EXTRACTION-TREATMENT SAMPLING PROCEDURES Ground water extraction and treatment influent,intermediate(AFT-AS)and effluent water samples I were collected on a monthly basis from valved ports located upstream(influent),after the air stripper (intermediate, AFT-AS) and downstream (effluent) of the treatment unit The grab water samples were collected utilizing 40-m1 EPA-approved VOA vials containing 0 5 ml 18%hydrochloric acid as a sample preservative and 1-liter amber bottles Care was taken to ensure that visible air bubbles were not present in the vials after filling and capping Ground water sample containers were labeled with a sample designation, date, time, and sampler's initials 43 LABORATORY ANALYSIS OF GROUND WATER EXTRACTION AND TREATMENT IInfluent,intermediate(AFT-AS)and effluent grab water samples were logged on a chain of custody form, placed in a chilled container and transported to a California Department of Health Services I (DHS)-certified laboratory to be analyzed for Advanced GeoEmironmeniai,Inc I