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Soil Vapor Extraction Test The soil vapor extraction test was performed on vapor extraction well VE-1, located in the source area of the former UST excavation Existing monitoring 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 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 (in 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, flow rate , 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 magnehelic gauges Off-gas concentrations were measured with a photo-ionization detector (PID) prior to treatment with the VACLEAN unit One off-gas sample was collected in a Tedlar bag at the end of the SVE 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 well 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 tankfield 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 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 (in w c ) was required to achieve this radius of influence PID readings (Table 4) measured in VE-1 show a steady increase in extracted VOC concentrations . during the pilot test A graph presenting the VOC concentrations versus vacuum (Appendix F) shows an increase in VOC levels with increasing vacuum III-3