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07 June 2012 AGE-NC Project No. 95-0184 Page 7 of 14 blower-driven IAS unit capable of approximately 5 to 10 psi to each sparging well at a rate of 2 to 3 scfm for shallow wells and approximately 15 psi to each deep sparging well. The proposed IAS system will consist of a 5-horsepower, electric air compressor that will generate a regulated pressure of clean air to be injected beneath the water table. From the outlet of the air compressor(located inside the treatment compound), 1-inch diameter PVC piping will connect to an IAS tubing manifold network; the IAS manifold will consist of a network of PVC ball valves, pressure gauges, air flow gauges and air pressure regulators for added controls to each individual air sparge well. A PVC ball valve, an air pressure gauge, an oil filter and an air pressure regulator will be installed at the outlet of the air compressor for added controls. 3.5. SOIL VAPOR EXTRACTION/IN-SITU AIR SPARGING REMEDIATION Based on results of SVE remediation, limited IAS pilot tests and in-well IAS performed at the site since December 2010 (utilizing soil vapor extraction well vacuum potential to agitate shallow ground waterwithin well and thus potentially volatilize dissolved petroleum hydrocarbons like benzene),AGE proposes to operate a dedicated IAS system, which will increase the effectiveness of SVE by targeting both adsorbed and deeper dissolved hydrocarbons in the saturated zone located at approximately 35 feet and 65 bsg. The proposed IAS system will consist of an air compressor and a network of two-inch wells, which will be used to inject air beneath the ground water table, through pressurized wells. Based on historic and recent ground wa r4 D 20.4, 3i'monitoring events performed at the site, depth to water generally ranges from feet bsg and seasonally fluctuates several feet during any given year. The successful remediation of the vadose zone is considered to be from near surface grade to approximately 30 feet bsg (water table). AGE has determined this phase of remediation completed on the residual adsorbed hydrocarbons in the vadose zone, located from near 10 feet bsg to 35 feet bsg; as soil vapor extraction recovery samples have been non-detect for several events over the last two quarters. The IAS remediation proposed will be conducted by injecting air into a drowned deep, depth discrete remediation well near the soil vapor extraction wells exposed to the upper water table. The most compatible well near the northern UST area for this air-sparge application would be well VW-5C, screened 45 feet to 55 feet bsg and deep vapor well VW-213 screened 44 feet to 54 feet bsg.This work plan does include the installation of sparging points near the southern UST area with deeper soil contamination; potentially, additional dedicated wells could be proposed instead of utilizing drowned soil vapor extraction wells. The injected air should volatilize dissolved hydrocarbons in the ground Advanced GeoEnvironmental,Inc.