FIELD DOCUMENTS_FILE 1 - Laserfiche WebLink

Home Browse Search

I� EXECUTIVE SUMMARY Harding tewson Asseclates i 1 This summary presents a remedial plan developed by Harding Lawson Associates (HLA) for The Southland Corporation, to treat groundwater and vadose soils at 455 West Grant Line Road in Tracy, California. The goal of the remediation effort is to treat soil and groundwater affected by a leaking underground fuel tank that was { removed in March 1989 . Specifically, this plan proposes to install a trench along the front of the store that will be capable of performing soil vapor extraction and if necessary, groundwater extraction. Extracted soil vapors will be treated with vapor phase granular-activated carbon (GAC) reactors connected in series before discharge to the atmosphere. If groundwater extraction is required, then liquid phase GAC would be used for treatment before discharge into the storm drain system. The Vapor Extraction System (VES) will consist of horizontal i PVC piping placed in the trench above the groundwater surface, , manifolded to the inlet of a vacuum blower. The exhaust of the blower will be connected to two activated carbon reactors in k series, which will adsorb all the hydrocarbon constituents before discharging to the atmosphere. The VES will be permitted by the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) . Influent and effluent vapor constituents, and system a yi flow rates will be measured on a regular basis determined by the SJVUAPCD. After operation of the VES for twelve months, the efficiency of the operation will be evaluated for improvement in groundwater quality. If results show the VES is not effective, groundwater pumping operations will commence from the trench into the storm drain. The groundwater will pass through three activated carbon reactors connected in series to remove the hydrocarbon contaminants before discharge. Groundwater treatment will be permitted with the Central Valley Regional Water Quality Control I Board (CVRQCB) and local agencies. The soils excavated during installation of the trench will j be treated on site before removal to a Class III landfill. The soil will be piled up on the western edge of the parking lot in front of the store. This pile will be covered with a plastic, waterproof liner, and contain lateral screened PVC piping which . will be connected to the VES. The VES will. draw the hydrocarbon constituents from the pile and pass the exhaust through the activated carbon reactors. 3 HLA estimates the length of remediation time at the Southland site will be long term. Operation of a soil and water remediation system could last five years or more. Modifications p such as installation of additional extraction wells (vapor or G groundwater) may be required to completely remediate the site or increase the rate of clean-up. 031869T/M9