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Mr Michael Infurna July 21, 2006 Page 4 Results Drilling Drilling, sampling, and installation of the wells were completed following the procedures specified in the Work Plan for Soil Vapor Extraction Well Installation and Soil Vapor Extraction and Air Sparge Pilot Tests (Brown and Caldwell,2005) The lithology of the screened interval was silty sand to sand consistent with the geologic cross sections provided in the Subsurface Investigation Results and Site Conceptual Model (Brown and Caldwell,2004) The hthologic boring logs for VEW-1 and VEW-2 are provided in Attachment A SVE-Only The field-measured differential pressures and the resulting calculated extraction well flow-rates are presented in Table 2 Three flow rates were tested during the SVE pilot test As indicated in Table 2, soil vapor extraction flow rates ranged from 75 3-standard cubic feet per nunute (scfm) at the start of the test to 160 6 scfm for the last step of the test,with an average flow rate of 100 scfm The applied vacuum ranged from 11-inches of water (in H2O) to 52 in H2O with an average of 23 in HBO Total VOC values in the effluent from VEW-1 decreased from a high of 11,060-parts-per-million (ppm) after 15 minutes of operation to 4,420 ppm at the end of the 7 5-hour SVE only portion of the pilot test The field-measured flow rate and total VOC values for the SVE only portion of the pilot test are presented in Table 2 and shown on Figure 3 According to the USEPA Bioventing Principals and Practice,Volume 2 (Office of Research and Development, 1995), the radius of influence (ROI) of a soil-vapor extraction well is defined as the distance from the extraction well at which a vacuum of 01 in H2O occurs Vacuum observation measurements were collected from VEW-2 during the SVE only portion of the pilot test (Table 2) At an applied vacuum of 52-inches H2O at VEW-1,vacuum pressures ranging from 4 5 to 4 75-inches HBO were observed at VEW-2 Using a value of 4 6-inches H2O, an estimated radius of influence would be approximately 22-feet (Figure 4) AS-Only The initial breakthrough pressure for the AS test was 6 5-pounds psi at 5 cfm Following operation of the system for 1 hour and 15 minutes, the pressure dropped to 6 psi and the flow increased to 7 cfm After an initial increase of dissolved oxygen concentrations in surrounding monitoring wells MW-2,MW-3, and MW-4, as shown in Table 3, the concentrations decreased over the duration of the AS test Groundwater elevations in MW-2 and MW-4 fell less than 1-inch while the groundwater elevation in MW-3 dropped 8-inches over the duration of the AS test The resulting gradient and direction during the AS test ranged from 0 02 ft/ft to 0 004 ft/ft to the northeast (Figure 5) ]'\280(X)\128253 I&f Trucking',VF\Documents\tiV L Kcport amw doc