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1 <br /> Off-Site Disposal <br /> This alternative involves the excavation of affected site soils and <br />' subsequent off-site disposal in an appropriate landfill The excavated area <br /> would be backfilled with clean material <br /> This alternative could be implemented in a timely fashion Landfilling <br /> costs for the soils at the site would be approximately $20 per ton <br />' Although off-site disposal does not treat the affected soils, based upon the <br /> expected low volume of soil to be excavated at the site, off-site disposal is <br /> considered a cost-effective and easily implemented remedial alternative <br /> ERM estimates that this alternative would cost approximately $10,000 to <br /> implement ($45,000 including excavation and dewatering) <br /> 1 <br /> Soil VentingNapor Extraction <br /> This alternative involves either passive or active removal of soil vapors <br /> from unsaturated soils without excavation Passive soil venting would <br /> involve the installation of perforated pipes into the affected soils to allow <br /> the volatile hydrocarbon constituents to vent The specific site soils would <br /> probably not respond quickly enough to passive treatment due to their <br /> low permeability In vapor extraction, a vacuum is applied to the <br /> perforated pipes to remove hydrocarbon-laden vapors from the soil pores <br /> The vapors are then either treated (via an air stripper or granular <br /> activated carbon unit) or released directly to the atmosphere (with an <br /> approved air permit) <br /> This soil treatment technology is implementable since it only requires the <br /> use of conventional drilling equipment and a vapor treatment unit Vapor <br /> extraction has also been proven to be effective at numerous sites and over <br /> a wide range of operating conditions However, vapor extraction is only <br /> effective for affected soils above the water table, and may not be effective <br /> in the clayey soils found at the site The low permeability of the clayey <br /> soil makes the extraction process difficult and time consuming To make <br /> the process effective, more wells would be required, increasing the cost of <br /> the alternative Even with the additional wells, treatment in clayey soils <br /> may not be sufficient For these reasons, vapor extraction was eliminated <br />' as an alternative for the site <br /> ERM estimates that this alternative would cost approximately $58,000 to <br /> implement ($93,000 including excavation and dewatering), with an <br /> estimated additional Operation and Maintenance cost of $20,000 (assumed <br /> for a one year duration) <br /> 4-5 <br /> 1 <br />