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&I <br /> N <br /> 16 April 1997 <br /> AGE-NC Project No , 95 -0121 <br /> Page 5 of 9 <br /> destruction. Optimal destruction will depend on four operational parameters : combustion <br /> temperature, volume of processed vapor, oxygen level and the lower explosive limits (%LEL). <br /> Vapor samples will be collected on a montWy basis . The samples will be collected in Tedlar bags and <br /> transported to a state certified laboratory for analysis of total petroleum hydrocarbons quantified as <br /> gasoline (TPH-g) and volatile aromatics (benzene, toluene, ethyl benzene and xylenes : BTE&X). <br /> Selected vapor samples may also be analyzed for TPH as diesel (TPH-d ) and methyl tert butyl ether <br /> (MTBE) . All analysis will be performed in accordance with the appropriate EPA and/or DHS <br /> methods. <br /> During the "start-up" period for the SVE system, organic vapor monitoring will performed on a daily <br /> basis. The anticipated start-up period will be approximately one to two weeks. <br /> 3 4 PROPOSED IN-SITU AIR SPARGING SYSTEM <br /> IAS is proposed in conjunction with SVE concurrently at the site. The proposed IAS system would <br /> consist of compressor to inject air beneath the water table using air sparging points. Approximate <br /> air sparging point locations are depicted in Figure 7 - Proposed Air SperrgingPoinlLocations. <br /> The compressor will provide between 3 and 10 pounds per square inch (psi) of air to each sparge <br /> point. The injected air will volatifize dissolved hydrocarbons in ground water, and force hydrocarbon <br /> vapors into the vadose zone, where they can be withdrawn by the SVE system. <br /> 3 . 2 . 1 . PROPOSED IN-S/TU .AJR SPARGING 1NTECTION POINTS <br /> Installation of seven IAS injection points are proposed utilizing direct push technology (DPT). Each <br /> IAS injection point will be installed using AGES van-mounted Geoprobe probing unit equipped with <br /> 1 . 125-inch diameter probe rods. Probing rods will be cleaned prior to advancement in each borehole. <br /> Sparging points will be advanced to depths of approximately 30 feet bsg. Soil probe borings will be <br /> completed as IAS injection points using 3/8-inch diameter teflon tubing and 3 '/2-feet of 3/8 -inch <br /> diameter stainless steel screen. Glass beads (50- 100 mesh) will be used as a filter pack around the <br /> injection point. An five foot interval of bentonite will be placed above the filter pack and will serve <br /> as an annular seal. Portland Type II cement will be utilized to grout from the annular seal to surface <br /> grade. Proposed IAS injection point construction diagrams are included as Figures 8 - Proposed Air <br /> SpargingPoint Design. <br />