Laserfiche WebLink
Former Discovery Chevrolet dune 5, 1998 <br /> Tracy, California Corrective Action Plan <br /> 5.2.1.2 Excavation and Aboveground Treatment <br /> If excavation and aboveground onsite treatment is the preferred method, the onsite treatment <br /> method could consist of either soil aeration, soil vapor extraction, or biotreatment of the <br /> excavated soil. Because of the large area of open, asphalt-covered space at the site, the <br /> expected warm summer air temperatures, and the fine-grained nature of the subsurface <br /> clayey soils, mechanical mixing and aeration may be the quickest onsite treatment method. <br /> Aeration involves thin-spreading of the excavated soils on an impermeable surface, such as <br /> asphalt, concrete, or plastic, to allow removal of petroleum hydrocarbons through <br /> volatilization. The thin-spread soils are periodically turned to maximize surface exposure <br /> and aeration. Naturally occurring microbes present in the soilsho also be able to <br /> convert both volatile and nonvolatile hydrocarbon components into primarily carbon dioxide <br /> (CO2) and water. <br /> After field evaluation of the aerated soil indicates concentrations of gasoline hydrocarbons <br /> E +' have decreased or are no longer present, the collection of soil stockpile characterization <br /> samples for laboratory analysis will be performed to verify the concentrations of gasoline <br /> hydrocarbons remaining in the soil, if present. After laboratory analysis, a determination <br /> will be made as to the selection of the appropriate landfill for disposal, or if gasoline <br /> hydrocarbons are no longer present in the soil, then the remediated soil may be utilized as <br /> onsite fill materials. <br /> As previously discussed above, residual hydrocarbon-impacted soil at concentrations less <br /> than 5 ppm benzene would remain in the soil after the completion of the excavation <br /> operations. Exposure risks to humans and the environment from the remaining residual <br /> hydrocarbon-impacted soil would likely be minimal. <br /> Preliminary costs for the excavation, stockpiling, mixing, and spreading of hydrocarbon- <br /> impacted soil are estimated to be approximately $11,000 to $13,000. Preliminary costs <br /> estimated for the backfilling and compaction of overburden and imported soils in the <br /> excavation are estimated to be approximately $8,000 to $12,000. Preliminary costs for the <br /> 3001-21.cap 12 HORIZON ENVIRONMENTAL INC. <br />