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1 <br /> 3.2.5 Alternative 5 - Soil Vapor Extraction with Groundwater Extraction <br /> This alternative involves remediation of impacted soils by vapor extraction with remediation <br /> of groundwater by extraction and subsequent treatment Initiation of these systems would <br /> include the following activities preparing plans and specifications, obtaining necessary <br /> permits, and installing the vapor and groundwater extraction piping, treatment compound(s), <br /> and treatment device(s) (Thermal oxidizer, air stripper, and/or granular activated carbon) <br /> The extraction system(s) would be monitored at least monthly or at the frequency specified <br /> by the appropriate permits Groundwater monitoring would continue on a regular basis until <br /> project completion <br /> ' 3.3 Remediation Alternatives Evaluation <br /> ' Each of the alternatives presented above were evaluated according to the following criteria <br /> 1 Level of protection of human health and the environment <br /> ' 2 Reduction of toxicity, mobility and volume of contaminants <br /> 3 Compliance with regulatory guidelines <br /> 4 Cost effectiveness/public benefit <br /> 5 Short term effectiveness <br /> 6 Long term effectiveness <br /> 7 Implementability <br /> 8 Regulatory and community acceptance <br /> 3.3.1 Alternative 1 - Passive Remediation <br /> ' o <br /> Criterion 1 <br /> The passive remediation alternative has no immediate health based risks The <br /> impacted media exists at depths greater than 15 feet, and since the site is paved, the <br /> possibility for exposure to humans by volatilization, dust or dermal contact with <br /> impacted soil is minimal, with little or no fire or explosion hazard The aquifer is <br /> currently classified as a drinking water source but is not generally used as such <br /> a Criterion 2 <br /> This alternative would reduce the existing levels and volume of impacted soil and <br /> groundwater over tune by natural degradation, but the rate of reduction is not <br /> known The possibility of ongoing migration of gasoline hydrocarbons in soil <br /> caused by surface water flushing contaminants into the groundwater exists in the <br /> short term until the existing excavation is backfilled and an asphalt cap is installed <br /> across the site surface <br /> A6 <br /> grourndne roek%cap <br /> ' 12 <br />