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CorreC N e Action Plan 5.2 Treatment of Extracted Soil Vapor Emission of extracted and treated soil vapor at this site will be ennatted b the San Joaquin P Y q Valley United Air Pollution Control District (SJVUAPCD) The hydrocarbon concentrations in the extracted soil vapor must be reduced to meet SJVUAPCD's site-specific standards GAC as recommended for the treatment of extracted soil vapor both on the basis of its proven reliability and its cost At this site, the total amount of hydrocarbons in the soil can be estimated with a reasonable degree of certainty It as apparent that for the SVE process, several GAC change-outs will be required over the duration of the remediation project As much as 25,000 lbs of GAC may have to be expended to treat the extracted soil vapor At present prices, however, the costs for replacement and regeneration of the spent carbon will far more than off-set the much higher initial cost for a thermal/catalytic oxidizing unit, additional costs for auxiliary fuel, and the 1 considerably higher costs of maintenance The capacity of the proposed SVE extraction system as 100 standard cubic feet per minute (scfm) Iat a vacuum of 12 inches of mercury The treatment system will consist of two I,000-lb canisters of vapor-phase GAC which are capable of accommodating more than 500 scfrn Mayor System Components Four SVE/Groundwater Extraction Wells Soil Vapor Transport Piping 100-scfm Positive Displacement Vacuum Extraction Pump 1 Moisture Knockout Device with Automatic Water Discharge Two 1,000-]b Vapor-Phase GAC Canisters 53 Treatment of Extracted Groundwater Extracted groundwater must be treated to remove petroleum contaminants prior to discharge to the surface drainage under an National Pollutant Discharge Elimination System (NPDES) permit or to the sanitary sewer system under a permit from the City of Manteca Public Works Department The proposed groundwater treatment system is designed to meet the most stringent 1 requirements from either permitting agency Not only as GAC presentl) the most cost-effective and reliable groundwater treatment method for this site, GAC adsorption offers the greatest flexibility for treating N aryang rates of groundwater production and can, therefore, accommodate any remaining hydrogeologac uncertainties OST proposes to use two I,000-lb canisters of aqueous-phase GAC to treat the water preceded by a bag filter to remove particulate matter Groundwater will be pumped from the four co-extraction wells using 5-gallon-per-minute (gpm) electric turbine pumps designed to provide automatic groundwater table drawdown control OST 701-1-2 cap Pae 1 1