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W <br /> r � <br /> r <br /> c ' <br /> 0 <br /> 8 <br /> 1 <br /> Specification RM25--0.1 <br /> and Instrument Diagram(P&ID)for the Vapor Extraction System and illustrates <br /> ,w the configuration of the carbon beds. The blower and carbon beds would be <br /> located inside the dock area as shown on Figure 3. The carbon beds are rated <br /> at approximately 60 CFM and each contains approximately 180 pounds of <br /> activated carbon. The configuration that is shown in Drawing M-1 would allow <br /> unrestricted discharge of the blower and a lead-polish arrangement to prevent air <br /> pollution when the lead units are exhausted. These units can be regenerated and <br /> recycled for future use. <br /> ` 4.4 Two-inch diameter PVC piping would be used as vapor conduit between the well <br /> and the blower, between the blower and the carbon beds,and between the lead <br /> and polishing carbon beds. Piping runs would be minimized by locating the <br /> blower and carbon units as close as possible to the extraction well. <br /> 4.5 Air velocity between the header pipe and the blower would be used to estimate <br /> air-extraction rates during the Pilot Test. Air velocity would be measured by <br /> } correlation of a vacuum gauge,located in the blower suction piping,with blower <br /> performance curves. <br /> 4.6 Sample taps for the collection of vapor samples would be located at the inlet to <br /> t , the first stage carbon units and at the outlet of the first an-d second stage units. <br /> Samples would be collected and analyzed as described below in the sampling <br /> plan. An additional sampling tap would be located at the inlet and the outlet of <br /> ..; one of the first stage carbon beds. <br /> 4.7 Two surge tests would be performed,during which time the blower would be shut <br /> down.Two such tests are anticipated. The first test would allow the subsurface <br /> vapor to equilibrate for 24 hours before restarting the blower. VOC <br /> concentrations would be measured at the vapor inlet during blower restart. Inlet <br /> E, VJC concentration values would be used to evaluate the cost-effectiveness of a <br /> catalytic oxidizer vs. carbon and intermittent operation of the full scale system. <br /> Savings on power cost and carbon consumption may be realized by intermittent <br /> t�• operation. The second test would be done with a longer or shorter equilibration <br /> time as established empirically from the resLits of the first test. Additional surge <br /> j tests would be conducted if needed to optimize the most economical operational <br /> lm interval. <br /> ` 4.8 Vadose-zone permeability would be estimated by using techniques that are <br /> analogous to aquifer testing in a confined aquifer system. Pressure drawdowns <br /> # would be obtained from water levels in manometer tubes that are located at <br /> radial distances from the extraction well of approximately 15,30 and 50 feet. The <br /> manometer tubes would be installed by drilling an 8"borehole and installing 1/Z' <br /> PVC pipe (for the 30' depth) and 3/4" PVC pipe (for the 63' depth). The top <br /> end will be open to the atmosphere, allowing measurement of the vacuum <br /> pressure from the subsurface interval at its radial distance from the extraction <br /> well. Volume rates of air extraction will be determined from the blower curve. <br /> A plot of pressure drawdown versus time will be used to estimate "gas <br /> B-3 REMEDIATION <br /> SERVICES. INC, <br />