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' 5 SOIL VAPOR EXTRACTION TEST <br /> Following completion of the soil and ground-water characterization activities, <br /> EMCON Associates conducted a SVET at the site on October 13, 1992. <br /> Since petroleum hydrocarbons were detected in soil at concentrations up <br /> to 6,200 mg/kg at 41 feet below ground surface, Teichert and EMCON <br />' Associates proposed conducting a SVET to determine whether SVE would <br /> be a feasible method of soil remediation. Appendix F presents EMCON <br /> Associates' standard SVE testing procedures and equipment. The following <br />' sections present details of the site-specific SVET procedures and results. <br /> 5.1 Site-specific Procedures <br /> EMCON Associate's field engineer used ground-water monitoring <br /> well MW-13 and one riser of the existing vacuum gallery, designated G-2, <br />' as extraction and monitoring points. Appendix G includes figures provided <br /> by others which identify vapor extraction piping locations in the existing <br /> vacuum gallery. Monitoring wells MW-1 , MW-3, MW-5, MW-12, and two <br /> risers of the existing vacuum gallery, designated G-1 and G-3, were used <br /> as monitoring points during the SUET. The locations of these extraction and <br /> monitoring points are shown on Drawing 1. <br /> Initially the SVET system imposed a vacuum of 90 inches of water column <br /> (in. wc) in well MW-13, and no measurable flow was generated. Ground- <br /> water upwelling apparently prohibited soil vapor from flowing into the well. <br /> The field engineer disconnected the SVET system from the well and within <br /> 10 minutes of disconnecting the SVET system, measured the ground-water <br /> level at 76.2 feet below ground surface (the ground-water level was <br /> 79.5 feet below ground surface before the SVET was started). The field <br /> engineer allowed the ground-water level in well MW-13 to stabilize for <br />' approximately 20 minutes and then measured the ground-water level at <br /> 79.0 feet below ground surface. The SVET system was reconnected to the <br /> well and soil vapor was extracted from well MW-13 at vacuums ranging <br />' from 10 to 31 in. we with corresponding flow rates of 14 to 20 cubic feet per <br /> minute (cfm) for a total test duration of approximately 65 minutes. Table 4 <br /> summarizes extraction well vacuum and flow rate data for the test. <br />' Soil vapor was extracted from vacuum gallery riser G-2 at vacuums of 15 <br /> and 21 in. we with corresponding flow rates of 39 and 44 cfm for a total test <br /> duration of 40 minutes. <br />' pj010f9010f900020.1 ag 5 - 1 Rev. 0 December 15, 1992 <br />