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Ms. Turkatte <br /> July 24, 2015 <br /> Page 3 <br /> SVE wells and the soil vapor monitoring probes meet the SJCEHD pressure grout method <br /> criteria. <br /> SVE System Construction and Operation <br /> As shown on Table 1 of Attachment 1, all of the SVE wells and the soil vapor monitoring probes <br /> were installed to a maximum depth of 30 feet below ground surface (bgs). Most of the SVE <br /> wells and soil vapor monitoring probes have a 20-foot screen interval from approximately 10 to <br /> 30 feet bgs. Based on data collected during SVE pilot testing, the SVE wells had a radius of <br /> influence (ROI) of approximately 80 feet and the SVE wells were installed with overlapping <br /> ROI's to more effectively remediate the impacted subsurface areas. <br /> The SVE system operated continuously at the Site for approximately ten years, beginning in <br /> 1999. During SVE system operation, soil vapor was extracted under vacuum from the SVE wells <br /> by a 2,000-standard-cubic-foot-per minute (scfin) positive displacement blower located at the <br /> treatment system near the northeastern corner of Douglas Avenue and Gettysburg Place. The <br /> vacuum pressure generated in the subsurface by the SVE system was monitored by the soil vapor <br /> monitoring probes. Extracted soil vapor was conveyed from the wells to the treatment system <br /> via a pipeline network of high-density polyethylene pipe. At the treatment system, soil vapor <br /> passed through a blower and was pushed by positive pressure through two Vapor Phase <br /> Granulated Activated Carbon vessels connected in series. The treated air was discharged to the <br /> atmosphere from the secondary carbon vessel as permitted by the San Joaquin Valley Unified <br /> Air Pollution Control District"Permit to Operate"Permit No.N-4043. <br /> SVE system optimization activities began in 2010. The system was optimized throughout <br /> multiple events at the direction of the RWQCB. The optimization activities are described in a <br /> number of previous reports including: Proposed Closure of the Phase II and Phase VI Interim <br /> Remedial Actions (Arcadis, 2010); Work Plan to Perform Additional Soil-Gas Sampling for <br /> Closure of the Soil Vapor Extraction Interim Remedial Action (Arcadis, 2012); Soil Closure <br /> Report (Geosyntec, 2012); SVE System Optimization Testing and Confirmation Soil Sampling <br /> Work Plan (Geosyntec, 2012); and the Soil Closure Report(Geosyntec, 2013). <br /> Baseline Soil Vapor Data <br /> As shown on the Remedial Investigation (RI) figures included in Attachment 2 and supported by <br /> data collected at that time, all of the SVE wells and the majority of the soil vapor monitoring <br /> addendumtoabandonmentwp.doc <br /> engineers I scientists I innovators <br />