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I19 December 2005 iAGE-NC Project No 99-0645 Page 6of8 I the pilot test versus the distance from the extraction well The effective radius of influence was determined by drawing a best-fit line though these data points to correlate distance to vacuum data At a vacuum potential of 0 10 Inches of water, the radius of influence is approximately 30 feet for I the lower screened well (V W 1 A) and radius of influence is approximately 40 feet for the upper screened well (V W 1 B), at an Induced vacuum potential of 1 0 Inches of water, the radius of Influence Is 20 feet for well V W 1 A and approximately 25 feet for well V W 1 B Furthermore, at a ' vacuum potential of 10 0 Inches of water,the radius of Influence is less than 10 feet Based upon an effective vacuum potential of 0 1 Inches of water, the calculated effective radius of influence at the site will be 30 feet up to almost 40 feet for the upper screened vapor well The majority of the residual Impacted soil would be collected within the 40-foot radius of Influence I3.0. SOIL VAPOR EXTRACTION We]I V W 1 B had been piped directly to the soil vapor extraction(SVE)unit located within a fenced I enclosure on the north side of the site (Figure 2) using 2-inch diameter Schedule 40 polyvinylchloride(PVC)piping In-line,the SVE system consists of a 55-gallon moisture knockout vessel for moisture separation and to prevent water collection within the treatment media, three 300-pound(lb)carbon canisters, then a Fuji 5-horsepower,regenerative vacuum blower capable of drawing a maximum 110 cfm of vapor, and finally two 1,500-1b carbon vessels to adsorb hydrocarbon vapor from the subsurface The SVE unit was operated in accordance with San Joaquin ' Unified Air Pollution Control District(APCD)permit 5984-1,the permit was canceled in July 2005 The SVE unit was observed or maintained weekly and monitored monthly During each monitoring ' event, the flow rate of extracted soil-vapor (Influent) was measured using a totalizing-flow Blue White roto-meter Vacuum potential was measured at the 2-Inch Influent line by the Magnehellc vacuum gauge In addition,the organic vapor concentrations in the Influent stream(before entering ' the blower) and the effluent stream(after exiting the carbon unit) were measured using the organic vapor meter equipped with a photo-ionization detector(PID Thermo Environmental 590b, 10 0 eV, calibrated to isobutylene) A Magnehelic vacuum gauge was temporarily attached to the inlet of the ' blower to measure vacuum pressure exerted on the extraction well,and a cumulative flow meter was utilized downstream of the carbon canisters to monitor air flow Sampling ports were installed upstream of the knockout vessel and downstream of the 1,500-1b carbon vessels to recover influent and effluent SVE air flow samples used to monitor the efficiency of hydrocarbon removal, in addition,the influent and effluent streams were monitored routinely for the presence of organic vapor using a PID Influent vapor samples were collected from within a vacuum chamber directly Into Tedlar vapor bags, the effluent samples were collected directly out of the effluent stream Field measurements were recorded at regular Intervals and are summarized in Table 4, analytical results Iof SVE vapor samples are summarized in Table 5 The SVE system was operated between October • 2004 and July 2005,at which time the operation of the system was terminated due to lack of influent Advanced GeoEnvironmental,Inc