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V. PREPARATION OF THE INTEGRATED CORRECTIVE ACTION PLAN <br />A. A detailed description of the remediation alternative or alternatives selected <br />which will be used to remove or stabilize contamination released into the <br />environment, or threatened to be released into the environment. The remediation <br />alternative proposed may include a request for no further action, if appropriate. <br />Acceptance of the proposed alternative(s) will be based on the site meeting State <br />standards or risk-based cleanup goals within an agreed upon time frame. <br />' As discussed in Section IV. C., E-21 proposes a multi-faceted remediation <br />approach to remove or reduce BTEX compounds in soil and groundwater to <br />below the soil and groundwater cleanup levels discussed in Section IV. A. These <br />include the following activities: <br />Phase I - Hazardous Waste Removal (Slurry Holding Trench) <br />Gross removal of the slurry, and sidewall and bottom wall soils in the SHT. <br />Excavation will proceed and confirmation sampling will be performed from the <br />sidewall and bottom of the excavation until the material is no longer considered a <br />' hazardous waste. This is the only area where gross removal and disposal of <br />hazardous waste is necessary. There was approximately 375 cubic yards of <br />"slurry" in the trench. We estimate 600 to 700 cubic yards will be excavated for <br />off-site disposal at a hazardous waste disposal facility after sidewall and bottom <br />soils are removed. <br />Phase II - Non-Hazardous Waste Removal <br />After material classified as hazardous waste is removed from the SHT, removal <br />of soils around the perimeter of the SHT that contain BTEX levels in excess of <br />' the CHPHE Soil Cleanup Standards (Protective of Groundwater) will be <br />excavated for off-site disposal as a special "petroleum contaminated" waste. <br />Excavation will be performed and confirmation samples will be collected at <br />regular intervals until groundwater is encountered or excavation becomes <br />' impractical. However, in the area of the SHT, lateral or vertical migration of <br />contaminants appears to the limited. We estimate approximately 1,200 to 1,500 <br />cubic yards of soils may require excavation in this phase from the SHT area. <br />' Also, there is approximately 300 cubic yards of material in the slurry wall <br />excavation to the west of the release area that is impacted with gasoline. This <br />material does not contain BTEX concentrations in excess of the CDPHE Soil <br />Cleanup Standards (Protective of Groundwater), however it may continue to be a <br />source of contamination to groundwater. Gross removal of this material will be <br />performed for off-site disposal. The excavation extends over 25 feet bgs and <br />' groundwater is approximately 12 feet bgs. Sandy and gravelly deposits range <br />from 8 to 12 feet bgs in this area. Excavation of the backfill will extend to <br />groundwater, if the excavation does not cave in. If caving occurs at shallower <br />' depths, excavation may be discontinued. It is expected that in both these areas, <br />a significant amount of uncontaminated overburden may need to be excavated <br />and backfilled. Soils will be segregated for, waste disposal and backfill <br />determination. <br /> <br />21 <br />