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25 March 2009 <br /> AGE-NC Project No. 95-0121 <br /> Page 2 of 9 <br /> upper portion of the saturated zone; typically trapped in fine grained soils. <br /> Due to the burial of the adsorbed contamination, the dual phase system can <br /> often be more cost effective than ground water extraction. <br /> Disadvantages: The effectiveness of this technology is sometimes dependent upon <br /> sufficiently lowering the water table to allow vapor extraction to remove <br /> hydrocarbons from the capillary fringe and saturated zones. Deep screened <br /> wells must be utilized to adequately de-water the site. <br /> Discussion: Based on this review of site conditions (depth ofimpacted soil and high water <br /> table over the impacted soil, with a significant dissolved phase concentration <br /> of hydrocarbons and fuel additives) high vacuum dual phase extraction is <br /> considered a viable option for this site, especially on an interim basis. The <br /> capability of remediate the three phases of hydrocarbons and treating the <br /> vadose, capillary fringe and upper saturated zones within a rapid time frame <br /> are particularly well suited to the existing conditions and requirements. <br /> 3.0. SCOPE OF WORK <br /> Based on the results of a dual-phase extraction (DPE) pilot test conducted at the site in December <br /> 2007, AGE proposes to install, operate and maintain an interim DPE remediation system utilizing <br /> existing site wells EW-1 , VW- 1 and AW4 . The projected soil vapor radius of influence, based on <br /> data collected during the December 2007 DPE pilot test for well EW- 1 , is depicted in Figure 3. A <br /> list of interim remediation field activities will consist of the following tasks: <br /> • Permitting and pre-field work activities; <br /> • Electrical power upgrade; <br /> • Installation of underground remediation piping system; <br /> • Installation of remediation fenced enclosure; <br /> • Installation of dual-phase extraction remediation system; <br /> • Interim remediation start-up period and continual operation of dual-phase extraction; <br /> • Monitoring and maintenance and <br /> • Preparation of reports. <br /> Each of these tasks are discussed below in detail. <br /> Advanced GenEnvironmentnl, Inc. <br />