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kn K L E I N F E L D E R <br /> 3. PILOT TEST THEORY AND APPROACH <br /> The pilot test will involve installing one air sparging/soil vapor extraction well in the source area <br /> and operating it for one week to test the response in nearby monitoring wells. Response data will <br /> then be used to evaluate the radius of influence of the sparge well, the ozone travel dynamics and <br /> resilience in the subsurface, and the anticipated extracted gas concentration. In addition, an <br /> ozone sparging bench scale test will be performed with groundwater from MW-DIS-11 to <br /> j evaluate the effectiveness of ozone to treat DCA exclusively. <br /> This section outlines the theory of the technologies to be tested and the proposed duration and <br /> specific technical objectives of the pilot testing. <br /> 3.1 THEORY OF PILOT TEST TECHNOLOGIES <br /> 3.1.1 THEORY OF VAPOR EXTRACTION <br /> Vapor extraction removes contaminants from soil by moving air from the soil pores containing <br /> vapors that are in equilibrium with the adsorbed and dissolved constituents. The removal of soil <br /> vapor in physical-chemical equilibrium (i.e., at partial pressure saturation) with the liquid, <br /> aqueous and adsorbed phases for the contaminant disturbs this equilibrium. Each component <br /> then volatilizes as the system tends toward re-establishment of the equilibrium. The rate of <br /> volatilization for each compound is controlled by many factors, including vapor pressure at soil <br /> temperature, aqueous solubility, and soil adsorption/desorption equilibrium, which is a function <br /> of the organic carbon content of the soil. Vapor is removed via vapor extraction wells installed <br /> in the unsaturated contaminated soil (vadose zone). As the vapor-laden air is extracted and <br /> replaced by fresh air, additional constituents volatilize from the soil and soil pore water to the air <br /> in the soil pores, reducing the amount of adsorbed and dissolved constituents remaining in the <br /> soil. The volatilization of the three phases occurs tore-establish the equilibrium condition prior <br /> to the removal of the contaminants. In this pilot test, the primary function of the soil vapor <br /> extraction portion of the pilot system will be to capture contaminants stripped from the <br /> groundwater by an air sparging system. <br /> { <br /> 12280/2002R476 Page 6 of 26 <br /> Copyright 2002 Kleinfelder,Inc. May 17,2002 <br />