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. . . ��$ate,` CTE'LEARWAR - G• R 'O U-P, 1 N C. " PVC casing and 20 feet of screen with p.020-inch-wide slots .(Figure 3). A sand' filter pack will be constructed using No. 3 sand. The annular space in all wellswill be filled with filter pack sand,to a depth , that is,approximately one to three feet above the top of the slotted screen. At ' the 'top of the filterack p the wells will be sealed usinga layer of hydrated ' - . ' . bentonite at least two feet thick. The' remainder of the' annulus will be filled with neat'cement'or acement/bentonite-mixture (Appendix.A): Soil Va r Extracti n We1I Four soil borings will be drilled and converted to SVE wells in the area of the large backfilled excavation after asphalt paving has been placed at the surface. Figure 2 presents the proposed SVE well locations. -(Note .that these locations may ,be .modified - if shoring has been installed in the excavation' and l ;. additional soil has been removed.) ' . The, wells will be constructed of two-inch-diameter' Sche f. dule 40 PVC.casing and screen with 0.020-inch-wide slots (Figure 4). Two of the SVE wells will be h� - screened from - approximately 20 to 30 feet b gs, within the ,sand layer encountered in monitoring wells MW-1 through MW-3. The other two wells will be screened fromapproximately 35 to 45 feet bgs in more fine-grained, material which underlies the sand. 2.4 SVE Pilot Testing :After'the SVE wells have been installed, Clearwater will conduct a pilot test to . measure vacuums at the test wells; vacuums in. surrounding wells, flow rates, and the- concentrations of volatile compounds extracted. ,The objectives of conducting an SVE ilot test are to ob P taro information regarding `the radius of influence, the relative" pe'rrnieability •of strata, and. number of extraction wells required at the site. The testing will be conducted in'•accordance'with the protocols presented i n Appendix B. It is anticipated that the,extraction' test will be conducted using a^ 3'/4 horsepower regenerative,blower with extr ' acted soil vapor removed from the effluent air stream by passing 'the effluent through vapor,phase' granular activated carbon' (GAC): The GAC will be c arranged in series. ontained in 55-gallon drums . Twb..wells,'will be used as vapor extraction points; one that is screened in the sand layer, and another that is screened in the fine-grained strata beneath .it. ., Vapors will be extracted from, each'weil for.aeriod p of approximately three Q,105WP 7,95 �y t8