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IAir sparging, as an in-situ treatment, appears feasible to meet the remedial objectives at this site <br /> Based on the site conditions, an air sparge system would be implemented by installing sparge <br /> I and vent wells along the approximate centerline of the groundwater plume This remediation <br /> system would also require surface trenching and installation of a treatment compound for <br /> sparging and venting equipment Characteristics that should be evaluated include vadose zone <br /> I gas permeability, groundwater flow rate, radial influence of the sparging well, aquifer <br /> permeability and heterogeneities, and contaminant volatility and solubility Air sparging may be <br /> classified as a medium to long duration technology Combined air sparging and venting pilot <br /> tests should be performed to further determine the feasibility of this technology and to define the <br /> remediation time frame and parameters Typical costs for air sparging range from $150,000 to <br /> $350,000 per acre of groundwater plume to be treated <br /> In-situ well aeration appears feasible to meet the remedial objectives at this site This technology <br /> is very similar to air sparging Based on the site conditions, an in-situ well aeration system <br /> I would be implemented by installing wells along the centerline of the groundwater plume This <br /> remediation system would also require surface trenching and installation of a treatment <br /> compound for sparging and venting equipment Characteristics that should be evaluated include <br /> Ivadose zone gas permeability, groundwater flow rate, radial influence of the aeration well, <br /> aquifer permeability and heterogeneities, and contaminant volatility and solubility In-situ well <br /> aeration may be classified as a medium to long duration technology Combined air sparging and <br /> Iventing pilot tests should be performed to further determine the feasibility of this technology and <br /> to define the remediation time frame and parameters Typical costs for m-situ well aeration <br /> should be similar to air sparging <br /> 4.3 Pilot Testing <br /> Based on the technology screening results, an air sparge/soil vapor extraction pilot test and <br /> enhanced bioremediation bench scale studies were conducted at the site <br /> Well Installation and Soil Sampling <br /> Three wells were installed in the vicinity of the former tank pit (near wells MW-13/13A/13B) for <br /> the SVE/IAS pilot testing and collection of soil samples for chemical analysis and treatibility <br /> studies One two-inch diameter SVE well (VE-1) was installed in the vadose zone with a screen <br /> section extending from 10 to 40 feet below ground surface (bgs) One nested SVE observation <br /> point(VE-2) consisting of two 2-inch diameter wells was installed in the vadose zone with <br /> screen sections extending from 15 to 25 feet bgs (VE-2B) and 30 to 40 feet bgs (VE-2A) One <br /> two-inch diameter IAS test well (IAS-1) was installed with a 5-foot screen section set <br /> approximately 3 feet below the water table An additional boring (SB-14) was installed in an <br /> unaffected area of the site near momtor well MW-2 for collection of treatibility samples The <br />' Well Permit Application Form and boring logs showing the well completion details and are <br /> included in Appendix A <br />' Soil samples were collected from well boring VE-1 for BTEX/MTBE and TPH analyses to <br /> assess the current soil conditions in the source area The two samples retained for chemical <br /> analysis were collected from depths of 20 and 35 feet bgs The samples were sealed in glass jars <br /> 0 <br />' YICE$' <br />