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Site Background Information: Former Ocampo Property <br />Page 6 of 6 <br />SOIL VAPOR EXTRACTION (SVE) PILOT TEST <br />On 29 July 2008, a 12-hour SVE pilot test was conducted at the site using vapor well VW-1 <br />(screened 10 feet to 35 feet) as the extraction well. TPH-g was reported in the Influent soil- <br />vapor samples at concentrations ranging from 40,000 pg/I to 84,000 pg/I; benzene, <br />toluene, ethylbenzene and total xylenes were reported in the soil-vapor samples at <br />concentrations as high as 310 pg/I benzene, 4,200 pg/I toluene, 510 pg/I ethyl benzene and <br />2,840 pg/I total xylenes; TAME was reported at a maximum concentrations of 280 pg/I. <br />Utilizing data gathered from the SVE pilot test, at a vacuum potential of 0.10 inches of <br />water, the radius of influence is approximately 40 feet; at an induced vacuum potential of <br />1.0 inches of water, the radius of influence is approximately 27 feet; at 10.0 inches of <br />water, the radius of influence is approximately 9 feet. <br />During the operational period, the combined mass of SVE hydrocarbons extracted by SVE <br />operations was calculated to be approximately 153 lbs of gasoline, or equivalent to a <br />volume of approximately 24.5 gallons of gasoline. <br />Based on overall high hydrocarbon concentrations in soil-vapor samples and the calculated <br />effective radius of influence (approximately 40 feet), AGE concluded, SVE could be used <br />as a feasible remediation method at the site as SVE should effectively reduce adsorbed <br />hydrocarbon concentrations in vadose zone soils through the use of a vacuum that creates <br />a negative pressure gradient to cause movement of vapors toward the extraction wells. <br />SOIL VAPOR EXTRACTION REMEDIATION <br />Between 28 December 2010 and 22 August 2011, an SVE remediation system was <br />operated at the site. On 04 February 2011 the natural gas-fired, thermal oxidizer SVE <br />system was removed from the site and replaced with a granular activated carbon (GAO) <br />adsorption vessels SVE system to continuously apply an induced vacuum to well VW-1. <br />SVE procedures for the site were described in AGE-prepared Interim Remedial Action <br />Work Plan (dated 14 September 2009) and Interim Remedial Action Work Plan Addendum <br />(dated 10 February 2010), and approved by the San Joaquin County Environmental Health <br />Department (SJCEHD) by letter dated 08 October 2009. <br />Based on SVE vapor remediation data collected between 06 June and August 2011, AGE <br />concludes the SVE system appears to be effective at extracting hydrocarbons from the <br />subsurface. A total of 1,321 gallons or 8,258 pounds of hydrocarbons as gasoline have <br />been extracted since startup of the soil vapor extraction system. <br />Advanced GeoEnvironmental, Inc.