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Geologieal Teeluucs lwc. <br /> Interim Remedial Action Plan Page 9 <br /> f Project No.622.2 <br /> March 28,2005 <br /> from EW-1 and this is sufficient to generate data from which aquifer characteristics can be <br /> determined. During the pilot test the flow rate had to be reduced to preclude overfilling the <br /> storage tank. Once the well is pumped at higher flow rates it is expected that a cone of <br /> depression will form and expose more soil to vapor extraction influence. <br /> A dedicated submersible pump will be placed in EW-1 and fitted with a control valve so the <br /> Cextraction rate can be adjusted. The extracted water will be plumbed to the treatment <br /> compound described above in section 3.1.2.2. <br /> 3.2.2 Groundwater Treatment— Carbon filtration <br /> The extracted groundwater from EW-1 will be treated by carbon filtration as outlined in <br /> section 3.1.2.2 above. <br /> 3.2.3 System Control <br /> y & Monitoring . <br /> GTI will perform monitoring of the system to obtain maximum contaminant removal <br /> f efficiency and compliance with regulatory permits. <br /> The monitoring will include: <br /> • Groundwater elevation measurements in site wells; <br /> • Water flow measurements for mass removal calculations; <br /> r- • Sampling ports on the effluent of the lead/intermediate carbon vessels. 4 <br /> Water sampling will be conducted as outlined above in Section 3.1.3.2 <br /> 4.0 ASSESSMENT OF REMEDIAL EFFECTIVENESS 3 <br /> 4.1 Source Removal <br /> After the dual phase extractions stem is installed and is operating at full capacity, a radius of <br /> Y p g p Y� <br /> influence test will be performed. The radius of influence testing will be performed to ensure <br />` that the extraction is sufficient to affect the entire site. <br /> Vapor concentration and flow rate measurements will be used to determine contaminant <br /> removal rates. GTI will attempt to quantify the amount of residual contamination by <br /> determining the amount of contaminants removed and subtracting from the original estimates <br /> provided in our February 20, 2004 "Additional Site Characterization" report. <br /> If the system reaches asymptotic conditions then it will be placed in pulse mode to allow the <br /> subsurface to equilibrate. A work plan addendum will be prepared for SJC/EHD approval <br /> prior to placing the system in pulse mode. <br />