Laserfiche WebLink
15 November 1995 <br /> AGE-NC Project No 95-0142 <br /> Page 9 of 19 <br /> 614 FEASIBILITY <br /> Generally, a vacuum of at least 0 10 inches of water is required to successfully volatilize subsurface <br />' hydrocarbons As stated in Section 5 4 ,the theoretical radius of influence at the site appears to be <br /> less than 20 feet Due to the clay-nch soil at the site, a strong vacuum will be required to create <br /> significant flow rates Additional soil vapor extraction wells may also be required at the Stockton <br />' Plating site _ <br /> A drawback of SVE is that not all contaminated zones of sod are remediated effectively or at the <br />' same rate For instance, a sandy soil will clean-up more quickly than a silt, SVE is not usually <br /> effective in sods with high clay content Other drawbacks of SVE include ineffective treatment of soil <br />' lying below ground water or within the "smear" zone and ineffective treatment of longer-chain <br /> hydrocarbons(diesel) Ground water remediation would need to be conducted concurrently with SVE <br /> to facilitate remediation of the smear zone <br /> 1 <br /> 615 DURATION <br /> Cleanup periods for soil vapor extraction typically range from 6 months to 3 years or more Based <br /> upon the plume size and the presence of clay-rich soil, we estimate a soil vapor extraction cleanup <br />' period of 24 to 36 months <br />' 6 16 ESTIMATED COST <br /> The costs for SVE systems vanes greatly, depending upon the particular system utilized for <br /> destruction of the extracted hydrocarbon vapors (thermal destruction, carbon adsorption, etc ) For <br /> the subject site, the cost to operate, maintain, monitor and sample an SVE system will likely average <br /> between $75,000 to $125,000 per year Rental/lease costs will likely comprise approximately <br />' $35,000 to $60,000 per year of the total cost Maintenance costs can vary significantly, depending <br /> upon the specific unit utilized <br /> 62- EX-SITU TREATMENT OF R"ACTED SOIL <br />' Hydrocarbon-impacted soil can be excavated and treated on-site or transported off-site for disposal <br /> On-site treatment alternatives (ex-situ) include aeration, bioremediation, vapor extraction, and <br /> thermal destruction All are feasible methods of remediating sandy soul contaminated with gasoline <br /> I However, increasing clay content hmits effectiveness Off-site disposal generally involves the <br />• transportation of the impacted soil to a licensed treatment/disposal facility <br /> I <br />