Laserfiche WebLink
1 <br /> ' Harding Lawson Associates <br /> volumes of groundwater through the saturated soil over an <br /> extended time period to flush out hydrocarbons fixed onto soil <br /> particles. This method has shown effectiveness in preventing a <br /> contaminated plume from migrating further, but does not address <br /> the source of the contamination in the vadose and capillary <br /> ' fringe soil. If soil venting is not able to reduce hydrocarbon <br /> concentrations in the groundwater, this alternative is <br /> recommended to be implemented to expose previously saturated <br /> capillary fringe soil to soil vapor extraction. <br /> 4 . In-situ-Bioremediation <br /> ' In-situ bioremediation entails stimulating <br /> microbial populations to metabolize hydrocarbons, thereby <br /> producing water, carbon dioxide, and biomass. This method was <br /> not chosen because of high maintenance expenses and complexities <br /> involved with confirming hydraulic control of the nutrient <br /> in3ection system. <br /> D. Soil Vapor Treatment Design Alternatives <br /> Design alternatives for treating soil vapors have been <br /> ' evaluated for performance feasibility at this site. Vendor <br /> solicitations will also be considered during the selection of <br /> equipment for the final treatment system. Four general design <br /> alternatives were considered: <br /> • Thermal oxidation; <br /> ' 0 Catalytic oxidation; <br /> " Granular activated carbon (GAC) media; and <br /> ' 13 <br />