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1 <br /> 9.0 PROPOSED ALTERNATIVE FOR REMEDIATION <br /> An evaluation of alternatives has shown Alternative 1 - Passive Remediation and Alternative 2 - <br /> ' Soil Excavation and off-site disposal to be less attractive for this site RESNA proposes to <br /> remediate hydrocarbon-bearing soil beneath the site by installing and operating a vapor extraction <br /> system (VES) and continue groundwater monitoring to ensure that groundwater has not been <br /> impacted The purpose of the VES is to remediate soil to reduce the leaching potential of <br /> petroleum hydrocarbons into the groundwater The system will include three vapor extraction <br /> wells, vapor phase carbon for the treatment of off-gas, a water condenser and associated piping <br /> Based on the results of the vapor extraction test conducted by RESNA, the radius of influence <br /> ' for vapor extraction within the impacted zone exceeds 30 feet Wells VW-1, VW-2 and VW-3 <br /> are screened from approximately 20 to 50 feet below surface grade These extraction wells <br /> should be capable of providing air flow through soil containing residual hydrocarbons (Plate 6) <br /> The three existing vapor extraction wells would be connected to a VES to draw hydrocarbon <br /> ' vapors out of the soil The major components of the VES are 1) a regenerative blower system <br /> for drawing vapors from soil, 2) a condensate removal system for removing trapped condensate <br /> in the vapor extraction piping, 3) two vapor phase carbon vessels connected in series for treating <br /> vapors, and 4) collection system piping, other associated piping, control valves and <br /> ' instrumentation The proposed location of the remediation compound and the piping system <br /> between the compound and vapor extraction wells are shown on Plate 8 <br /> ' The results of the vaporextraction <br /> p test dictate a wellhead design flow of up to 100 cubic Feet <br /> per minute (cfm) per well, or a total maximum design flow of 280 cfm The design vacuum is <br /> 30-inches of water column Based on the design parameters it is estimated that the VES will <br /> ' operate for approximately one year <br /> 1500471REPORMCAP 0694 FNL 16 <br /> - r <br />