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, <br /> i <br /> 'V. <br /> { <br /> A S S O C I A T E S I N C <br /> I <br /> that rise to the unsaturated zone, carrying trapped and dissolved contaminants. Vapor extraction <br /> f wells in the unsaturated zone capture sparged air. If necessary the effluent air can be treated <br /> L, .using a variety of vapor treatment options. This method also stimulates biodegradation by <br /> increasing the supply of oxygen in the subsurface. <br /> The advantages of in-situ air sparging with soil vapor extraction include: <br /> i <br /> • Short treatment times; usually I to 3 years under optimal conditions. <br /> • Readily available equipment and easy installation. <br /> • Implementation with minimal disturbance to aboveground activities. k <br /> • Requires no removal, treatment, storage, or discharge considerations for groundwater. <br /> • Cost competitive. <br /> • Can be used under buildings and other Iocations that cannot be excavated. <br /> E' <br /> I <br /> In order to determine the effectiveness of in-situ air sparging, pilot testing to evaluate the <br /> effectiveness would have to be performed at the site. Data provided by the pilot study would be <br /> used to properly design a full-scale in-situ air sparging system and soil vapor extraction system. <br /> A pilot test would require the installation of at least on air sparge well to a depth of approximately <br /> 70 feet bgs. Once the sparge well was in place, appropriate equipment would be plumbed to the <br /> well and a pilot scale study will be performed, then the in-situ air sparge and/or soil vapor <br /> extraction systems would be designed, installed and operated until remediation is complete. <br /> 5.0 REMEDIATION ALTERNATIVES EVALUATION <br /> Each ac of the alternatives presented above were evaluated according to the following criteria: <br /> I <br /> 1. Level of protection of human health and the environment <br /> 2. Reduction of toxicity, mobility and volume of contaminants <br /> 3. Compliance with regulatory guidelines <br /> 4. Cost effectiveness/public benefit F <br /> S. Short term effectiveness �. <br /> 6. Long term effectiveness <br /> 7. Implementability <br /> 8. Regulatory and community acceptance <br /> 'I <br /> S:1Environmenta11625771SCMCAPAdddoc 6 <br />