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(YVATC <br /> 1117 Lone Palm Avenue, Suite 1Modesto, CA 95351 <br /> www.atcassociates.com <br /> 209-579-2221 <br /> A S S 0 C I A T E S I N C . Fax 209-579-2225 <br /> Environmental, Geotechnical and Materials Engineers <br /> 3. 1 Soil Remediation Alternative <br /> 3. 1.1 Soil Vapor Extraction (SVE) <br /> SVE is a proven technology for effectively reducing concentrations of volatile organic compounds <br /> (VOCs) and certain semi-volatile compounds in soil. SVE is an in-situ unsaturated zone, soil <br /> remediation technology in which a vacuum is applied to the vadose zone soil to extract soil gas and <br /> remove volatile compounds in the vapor phase from the soil. The extracted soil gas is then treated as <br /> required before discharge to the atmosphere. This technology can be applied to remediate in-situ <br /> soils which are inaccessible to excavation. Additionally this technology is well suited to remove <br /> high vapor pressure, low boiling point compounds, such as those present in the petroleum <br /> hydrocarbon-impacted soil at this site. <br /> In order to determine the effectiveness of SVE, a vapor extraction pilot test would need to be <br /> conducted at the site. Data collected during the pilot test would be utilized to evaluate the necessity <br /> of soil remediation, as well as provide information to properly design a full-scale SVE remediation <br /> system. The installation of at least 3 SVE wells would need to be installed to conduct the pilot test. <br /> These wells would be screened in the vadose zone from approximately 10 to 40 feet bgs. <br /> Subsequently, a pilot test would be conducted using a mobile vapor extraction pilot test system. <br /> 3.2 Groundwater Remediation Alternatives <br /> 3. 2. 1 Groundwater Extraction <br /> The groundwater extraction alternative involves pumping contaminated groundwater out of the <br /> saturated zone with the use of groundwater extraction wells. Depending on the geology and soil <br /> type, pump and treat may be a good method to quickly reduce high concentrations of contaminants <br /> and also capture contaminants which have migrated off-site . Although, it is difficult to reach closure <br /> criteria concentrations due to the equilibrium of absorption/desorption processes in the saturated <br /> zone. <br /> In order to determine the effectiveness of groundwater extraction, an aquifer pump test would need <br /> to be conducted at the site. Data collected during the aquifer pump test would be utilized to evaluate <br /> the feasibility of this technology to remediate groundwater, as well as provide information to <br /> properly design a full-scale groundwater extraction and treatment system. In order to conduct the <br /> pump test at least three groundwater extraction wells would need to be installed. The extraction <br /> wells would be screened within specific lithologic intervals approximately 35 to 50, 60 to 80, and 90 <br /> to 110 feet bgs. <br /> 3.2.2 Ozone Sparging <br /> Ozone sparging is an in-situ saturated zone remediation technology which involves the process of <br /> sparging a mixture of ozone and atmospheric air into the saturated zone. The sparging component is <br /> essentially in-situ air stripping, in which bubbles containing air and ozone are injected into the <br /> s:\environmental\28349\reports\feasibility.doc 4 <br />