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• zone and lowers the level of static groundwater Three components must be considered in <br /> implementing vapor extraction technology, the vapor collection system, the air moving device, <br /> and the vapor treatment system <br /> The air collection system will consist of several vertical well points that currently exist on the <br /> property The western soil contarunation area will be treated by vapor extraction using wells <br /> TB4, TB6, and MW5 Each of these wells is accessible to a pre-installed vapor recovery line <br /> that extends to the proposed treatment area The eastern soil contamination area will be <br /> similarly treated using wells TB9, TB7, TB 12, and MW2, which are also connected to the <br /> mainline vapor piping Currently, there are no lines extending to the third area of <br /> contamination, near TB3 A separate line may be run to this well if necessary Also in an <br /> attempt to mitigate the downgradient portion of the dissolved plume, wells MW3R, TB8, and <br /> MW6 will be connected to the vapor extraction system The individual wells will be equipped <br /> with a ball valve to control flow from each well <br /> Based on the available information, a positive displacement blower capable of moving air at <br /> 200 cubic feet per minute(cfin) at about 75 inches of water vacuum will be sufficient for use at <br /> this site However, because of the high vacuums encountered with the low flow rates of the <br /> test, the blower should be capable of a wide range of flow performance so that it can be <br /> adjusted if necessary The actual operating flow rate of the system will likely be 100-150 cfn <br /> After removal from the subsurface, vapors will be treated by an appropriate medium Several <br /> technologies exist for treatment of hydrocarbon vapors These include activated carbon, <br /> catalytic oxidation, and thermal oxidation In determining which is most cost effective for any <br /> particular site, two important factors need to be considered The first is the volume and type of <br /> contaminant to be removed, the second is the contaminant removal rate and corresponding <br /> concentration of vapors in the air stream <br /> Page 9 <br />