ARCHIVED REPORTS XR0004311 - Laserfiche WebLink

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Remedial Action Plan and Further Site Assessment 11 7-Eleven Store No 19976, 1399 N Main St Manteca CA May 30 2000 60 REMEDIATION IMPLEMENTATION Traditional pumping methods will be used to control lateral dissolved MTBE spreading Extracted _ groundwater will likely be treated by an above-ground stripping/volatilization process, and the vapors will probably be routed to a thermallcatalytic oxidizer Treated groundwater will be passed through aqueous carbon as a polishing step prior to discharge to the nearest storm drain Prior to remediation system construction, all applicable local permits will need to be obtained, Including NPDES, local City permits (Including possibly Fire Department, Building Department, Department of Public Works, Planning Department, etc), and air discharge permits During design of the Interim remediation method, several of the proposed supplemental remediation alternatives will be evaluated for effectiveness and cost versus benefit relative to the baseline cost of groundwater extraction If indicated based on further study, supplemental remediation methods will be proposed under separate cover to the SJCPHS 61 Length of Remediation During remediation, hydrocarbon concentrations tend to decline over time to an asymptotic minimum, at which time the potential of the existing system for further remediation has been exhausted At that time, the site Is evaluated for either additional rernediation or site closure, if applicable Without relevant historical data related to the time frames typical for MTBE remediation, it is estimated that the decision point for this site will be reached within 2 years of system startup, assuming continuous system operation Actual recovery trends may differ based on site conditions Dissolved hydrocarbon remediation progress will be tracked by groundwater monitoring and extracted hydrocarbon concentrations in extracted materials (both groundwater and/or vapors) After hydrocarbon ' concentrations have reached stable minimum levels, site closure will be evaluated 62 Progress Monitoring Extracted waste streams will be monitored in accordance with permit requirements Dissolved hydrocarbon concentrations in the groundwater monitoring wells will be monitored quarterly during remediation, and semiannually after cleanup has been discontinued Groundwater samples will be analyzed by EPA Method 8015160218020 for dissolved TPH-G and volatile organic (petroleum)