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observation well MW-13A (0 1 feet), located approximately 16 feet from the sparge well Water levels measurements at the end of the sparge test (23 5 hours) had equilibrated to within 0 01 to 0 03 of a foot of initial readings, indicating that water levels in the nearby diverting canal may have had some influence on the water level measurements collected during the pilot test The dissolved oxygen measurements showed no consistent trends during the pilot test (Table 5), therefore, the data was not used as a determining factor in predicting the radius of influence Graphs of pressure influence, VOC concentrations, water levels, and dissolved oxygen versus ' time were also prepared and are presented in Appendix F In each of the monitored parameters, except for dissolved oxygen content, a response was I measured in both observation wells MW-13 and MW-13A (Table 5) A comparison of the data indicates that the responses were less pronounced in MW-13A than m MW-13 This is apparently due to both the greater distance from the sparge well (MW-13 @ 9ft and MW-13A @ 16 ft) and the location of the screen sections (MW-13 @ 39-59 ft and MW-13A @ 71-76 ft) Based on the measured responses in these wells, both a vertical and horizontal influence was produced across the unsaturated zone during the pilot test Combined Air Sparge/Soil Vapor Extraction Test ' A combined soil vapor extraction/air sparge pilot test was performed using VE-1 as a vapor extraction well and IAS-1 as an infection well The pilot test was operated at three different extraction and infection rates Existing monitor wells MW-1, MW-3A, MW-4, MW-13, and ' MW-13A and newly installed dual completion well VE-2 were used as observation wells during the test (Table 6) The monitoring points were selected to provide multi-directional data at varying distances from the infection point Vacuum and flow readings were measured with ' magnehelic gauges Off-gas concentrations were measured with a PID prior to treatment with the VACLEAN unit One off-gas sample was collected in a Tedlar bag at the end of the ' combined pilot test for laboratory analysis The combined soil vapor extraction/air sparge pilot test determined that a net vacuum was maintained at approximately 30 feet from the SVE well at a vacuum of 92 inches w c and a ' sparge pressure of 3 psi The results are presented in a graph(Appendix F) showing the pressure versus distance from the SVE well This data documents the capture of the air sparge off-gases ' within the design SVE radius of influence The off-gas analytical results showed a TPH(g) concentration of 62,000 ug/L, a benzene ' concentration of 85 ug/L, and a total BTEX concentration of 8,345 ug/L A copy of the analytical report is included in Appendix G Based on the analytical results, approximately 11 pounds of hydrocarbon vapors per hour (lbs/hr) were extracted from VE-1 during the combined t test 4.4 Recommended Remediation Technology 1 The results of the air sparge/soil vapor extraction pilot test indicated this is a feasible treatment technology for the impacted soil and groundwater at this site The results of the Enhanced 1 6G �o 13 ' 7C V-5