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thermal desorption, and soil fixation with reuse as daily landfill <br /> cover. <br /> This alternative would effectively remediate the soils at the site and <br /> could be easily implemented. However, the transportation costs <br /> associated with this alternative make it less cost-effective than <br /> equally effective available on-site treatment alternatives Therefore, <br /> off-site treatment alternatives are not presently considered as options <br /> for the site. <br /> Tanrifiilin� <br />' This alternative involves the excavation of affected site soils and <br /> subsequent off-site disposal in an appropriate landfill. The excavated <br />' area would be backfilled with clean material. <br /> Although this alternative would be effective and could be <br />' implemented in a timely fasluon, it is not cost-effective. Landfilling <br /> costs for the soils at the site would be approximately $150 to $210 per <br /> cubic yard In addition, landfilling does not provide treatment of the <br />' affected soils, and therefore is not preferred by the public or <br /> regulatory agencies For these reasons, landfilling has been <br /> eliminated as an alternative. <br /> iI Ventin9JVanor Extraction <br />' This alternative involves either passive or active removal of soil <br /> vapors from unsaturated soils without excavation. Passive soil <br /> venting would consist of the installation of perforated pipes into the <br />' affected soils to allow the volatile hydrocarbon constituents to vent. <br /> The specific site soils would probably not respond quickly enough to <br /> passive treatment due to their low permeability In vapor extraction, <br />' a vacuum is applied to the perforated pipes to remove hydrocarbon- <br /> laden vapors from the soil pores The vapors are then either treated <br /> (via an air stripper or granular activated carbon unit) or released <br />' directly to the atmosphere (with an approved air permit). <br /> This soil treatment technology is implementable since it only <br /> requires the use of conventional drilling equipment and a vapor <br />' treatment unit Vapor extraction has also been proven to be effective <br /> at numerous sites and over a wide range of operating conditions <br /> Vapor extraction is only effective for affected soils above the water <br />' table. However, it may not be effective in the clayey soils found at both <br /> sites. The low permeability of the clayey soil makes the extraction <br /> process difficult and time-consuming. To make the process effective, <br />' more wells would be required, increasing the cost of the alternative. <br /> Even with the additional wells, treatment in clayey soils may not be <br /> 74 <br />