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404 WEST FREMONT STREET <br /> WKA No. 1628.09 <br /> August 31, 2001 <br /> Page 9 <br /> screened interval to approximately two feet above the.top of the screened interval. A minimum <br /> 1 two-foot thick bentonite seal will be placed in the well annulus above the filter pack. A grout seal <br /> consisting of Portland cement and bentonite slurry will be placed into the well annulus above the <br /> U bentonite seal. Each well will be completed with a locking well cap and a flush-mounted, traffio- <br /> -- rated well cover. All drilling equipment will be steam cleaned as described above. All soil cuttings <br /> generated during drilling will be placed on a stockpile stored on site. <br /> The air sparging points will be connected to underground piping and stubbed-up,manifolded and <br /> connected to the air sparging unit inside the treatment enclosure. The air sparging points will be <br /> strategically placed in the petroleum hydrocarbon groundwater plume. The points will be spaced <br /> such that the entire zone of contamination receives maximum airflow. <br /> General Description of Soil Vapor Extraction System <br /> The soil vapor extraction system(SUES)will consist of a 280-cubic-foot-per minute(cf n) <br /> regenerative blower with a 5.5 horsepower explosion proof motor. The SUES will be equipped <br /> with.a 40-gallon moisture separator,fittings,magnehelic.pressure gauges,wellhead connections, a <br /> dilution valve, a pressure relief valve, shut-off valve, an in-line filter and sample ports. <br /> The SUES will be complete'with instrumentation for measuring the following: <br /> • airflow rate <br /> • temperature <br /> • vacuum pressure <br /> F. • volatile organic compound(VOCs) and petroleum hydrocarbon concentrations <br /> Approximately 140 lineal feet of Schedule 40 PVC piping will be installed underground in <br /> connected to the SVES unit via trenches. <br /> The SVES will be used to induce airflow and vacuum in the subsurface unsaturated and vadose <br /> zones in order to capture displaced petroleum hydrocarbons as a result of air sparging. Airflow <br /> rate in the vapor extraction well will be determined by measuring the pressure differential across an <br /> average pitot tube with a magnehelic vacuum gauge. Two carbon air filters connected in series will <br /> INK <br />