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AGE-NC Project No. 99-0559 <br />Page 4 of 13 <br />INSTALLATION OF GROUNDWATER RECOVERY WELLS <br />On 01 and 02 April 2003, four groundwater extraction well EW-1 through EW-4 were <br />installed on the site. The wells were single-completed as groundwater extraction wells with <br />a 4-inch diameter perforated well casing to a depth of 80 feet bsg. <br />INSTALLATION OF GROUNDWATER EXTRACTION SYSTEM <br />The groundwater extraction system consisting of the groundwater treatment unit and <br />associated piping was installed between 18 February and 26 June 2003. <br />GROUNDWATER TREATMENT OPERATION <br />The groundwater treatment system is designed to operate at a maximum flow rate of up <br />to 10 gallons per minute (GPM); each of the four recovery wells extracts groundwater at <br />a flow rate of approximately 2 to 2.5 GPM, by extracting on an intermitting cycle. The <br />operation of the pumps allowed for a hiatus when water fall below the pump inlet to allow <br />the well to recharge, after which the pump will reactivate. The groundwater treatment <br />system operates on a batch basis, with a daily total of up to 4,000 gallons. Once the <br />sediment holding tank fills, approximately 250 gallons of extracted groundwater is treated <br />and discharged. The discharge of treated water (effluent) to the City of Stockton was <br />adjusted at a flow rate of approximately 10 GPM. <br />A total of 12,568 lbs/2,010 gallons of petroleum hydrocarbons, 701.4 lbs/112 gallons of <br />benzene and 1,253 lbs/200 gallons of MTBE were removed from the site since the initiation <br />of SVE operation (May 2003). <br />SOIL VAPOR EXTRACTION SYSTEM INSTALLATION AND OPERATION <br />In early September seven SVE wells VW-1 VW1, VW-2A/B, VW-3A/B and VW4A/B and <br />one severely impacted monitoring well near the former UST area (MW-2) were connected <br />below grade to the remediation area. In October 2006 a Solleco thermal oxidizer SVE unit <br />was delivered to the site and installed with a fenced enclosure surrounding the <br />groundwater remediation system. In late November and December 2006 a dedicated <br />electrical service and high pressure natural gas line were connected to their respective <br />meters which service the building at the site. The SVE unit was tested in thermal mode for <br />operational readiness in early December. The system was receiving adequate <br />concentrations of hydrocarbons to warrant operation in the high temperature thermal <br />mode. <br />Advanced GeoEnvironmental, Inc.