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I—C\V'Y' <br /> 0 <br /> A S S o C 1 A T@ S I N C <br /> injected into the saturated zone The air forms bubbles that rise to the unsaturated zone, carrying <br /> trapped and dissolved contaminants Vapor extraction wells in the unsaturated zone capture <br /> sparged air If necessary the effluent air can be treated using a variety of vapor treatment <br /> options <br /> The advantages of in-situ air sparging with SVE include <br /> • Short treatment times, usually 6 months to 2 years under optimal conditions <br /> • Readily available equipment and relatively easy installation <br /> « implementation with minimal disturbance to above ground activities <br /> • Requires no removal, treatment, storage, or discharge considerations for groundwater <br /> • Can be used under buildings and other locations that cannot be excavated <br /> In order to determine the effectiveness of AS/SVE, a pilot scale study would first need to be <br /> performed at the site Data provided by a pilot study is necessary to properly design a full-scale <br /> AS/SVE system Pilot studies also provide information on the concentration of VOCs that are <br /> likely to be extracted during the early stages of the operation <br /> A pilot test would require the installation of three vapor wells to depths of 18 to 22 feet bgs and <br /> one air sparge well to a depth of 35 feet bgs Once these wells were in place, appropriate <br /> equipment would be plumbed to these wells and a pilot scale study will be performed, then the <br />' AS/SVE system would be designed, installed and operated until remediation is complete <br /> 8.0 REMEDIATION ALTERNATIVES EVALUATION <br />' Each of the alternatives presented above were evaluated according to the following criteria <br /> 1 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 <br /> 5 Short term effectiveness <br /> 6 Long term effectiveness <br /> 1 7 Implementability <br /> 8 Regulatory and community acceptance <br /> 8.1 Natural Attenuation with Groundwater Monitoring <br />' b Criterion I <br /> The natural attenuation alternative has no immediate health based risks The site is surfaced <br /> with asphalt and concrete so the possibility for exposure to humans by volatilization, dust, <br /> 1 or dermal contact with impacted soil and groundwater is minimal, with little or no fire or <br /> explosion hazard The closest potential receptor is the on-site well which is located <br /> w 1130991reportslsumweh doc 9 <br />