Laserfiche WebLink
1 <br />' Identification and Screening of Alternatives <br />' This section presents a description and evaluation of potential remedial <br /> alternatives for TPH-impacted soils at former Tank Site #2 The soil <br />' remedial alternatives evaluated included those listed in the PAR <br /> guidelines Due to site-specific conditions, some of these alternatives were <br /> not appropriate for remediating the site The inappropriate alternatives <br />' are discussed only briefly The remaining alternatives were evaluated <br /> according to the four criteria described above <br />' Excavation <br /> Excavation consists of the removal of the hydrocarbon-containing soils <br />' from the site with conventional excavation equipment (e g , backhoe) <br /> Clean soil would be imported to backfill the excavated area Given the <br />' presence of confined ground water conditions at the site, some dewatering <br /> may be required if the excavation approaches the depth of the silt- <br /> clay/sand contact A reduction in the thickness of the silt-clay layer <br />' overlying the saturated sand zone may result in a localized inducement of <br /> vertical ground water flow into the excavation <br /> Excavation by itself is effective in removing the affected soils from the site <br /> to limit potential migration of the hydrocarbons However, it is not <br /> effective in remediating the affected soils unless further treatment or <br />' disposal is undertaken Excavation would therefore be appropriate as <br /> part of other alternatives, but not as a separate remedial alternative for the <br /> site <br /> ERM estimates that this alternative would cost approximately $25,000 to <br />' implement If dewatering is necessary, this cost would increase to <br /> approximately $35,000, assuming that the Stockton POTW were willing to <br /> accept the untreated water, as in the past <br /> On-Site Ex Situ Soil Aeration <br />' This alternative would consist of excavating the affected soils and <br /> removing the volatile hydrocarbons from the soil via aeration The <br />' excavated soils would be spread over a treatment area at a depth of <br /> 6 to 8 inches, covered, and allowed to dry After the soils are dry, <br /> agricultural equipment would then be used to mix the soils, allowing the <br />' hydrocarbons to volatilize After the aeration is complete, the treated soils <br /> • could be backfilled into the excavation <br /> 4-3 <br /> I <br />