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' Air Sparge/ Soil Vapor Extraction Pilot Test An air sparge/soil vapor extraction pilot test was conducted at the site during the period from February 27 io March 4, 2002, to determine the feasibility of air sparging and in-situ well aeration technologies The pilot test was performed in three stages an air sparge test, a soil vapor extraction test, and a combined soil vapor extraction/air sparge test Data was collected during the pilot test to measure the system radius of influence, size equipment, and to assess off-gas treatment options Soil Vapor Extraction Test The soil vapor extraction test was performed on vapor extraction well VE-1, located in the former UST excavation source area Existing monitor well MW-13 and newly installed dual completion well VE-2 were used as observation wells during the test The monitoring points were selected to provide both horizontal and vertical data at varying distances from the extraction point I The pilot test involved extracting soil vapors from the extraction well using a VACLEAN Model 1000 Vapor Extraction Treatment System The system employs a 12 2 Hp belt-driven blower with a maximum vacuum capacity of 14 4 inches of mercury (Hg) Off-gas vapors were routed ' through the VACLEAN internal combustion engine and the exhaust was treated by a catalytic converter The pilot test was operated at three stepped vacuum and flow rates At each step, vacuum response levels were allowed to equilibrate before increasing the vacuum and flow rate ' at the extraction well During the pilot test, measurements of vacuum, flowrate , and off-gas concentrations were ' recorded for vapor extraction well VE-1 (Table 4) The observation wells were monitored for vacuum responses (Table 4) Vacuum and flow readings were measured with magnehellc gauges Off-gas concentrations were measured with a Photionization Detector(PID) prior to ' treatment with the VACLEAN unit One off-gas sample was collected in a Tedlar bag at the end of the soil vapor extraction pilot test for laboratory analysis ' Following completion of the pilot test,the data was tabulated (Table 4) and graphs (Appendix F) were plotted to assess the radius of influence of the SVE system Vacuum influence was measured in both observation wells MW-13 (19 5 feet from VE-1) and VE-2 (28 75 feet from ' VE-1) The vacuum response was very similar across both screened zones 15 to 25 feet bgs (VE-2B) and 30 to 40 feet bgs (VE-2A) in dual completion well VE-2 This indicates that soil ' vapor extraction would be effective in remediating soils throughout much of the vadose zone, including impacted soils in the former tankpit excavation area as well as those near the saturated zone ' A graph showing the natural log of the vacuum versus distance from vapor extraction well VE-1 (Appendix F) indicates that a radius of influence of at least 30 feet can be achieved in the vicinity t of the former UST source area As illustrated in the graph showing vacuum versus radius of influence (Appendix.F), a vacuum of 59 inches of water column(w c ) was required to achieve this radius of influence