Laserfiche WebLink
Closure Report 13 <br /> Golden Grain Manteca Bean Feal4ty,299 Moffat Boulevard,Manieca,California July 16,1996 <br /> 3 3.2 Groundwater Extraction <br /> Since the beginning of operation of the groundwater system, approximately 4,894,000 gallons of <br /> water has been extracted and treated by the groundwater treatment system Each quarter, influent <br /> and effluent samples were collected and analyzed for TPH-g, benzene,toluene, ethylbenzene,and total <br /> xylenes(BTEX),total lead, organic lead,and EDB at a California-certified laboratory Historical <br /> ' analytical results(table 8)indicate that all treatment system effluent water constituents analyzed were <br /> below the City of Manteca Public Works Department Industrial Wastewater Discharge Permit(No 92-2) <br /> limits The analytical results for total lead, organic lead, and EDB were not detected above the <br /> method detection limits after August of 1993 All influent and effluent analytical laboratory results <br /> from quarterly system sampling have been presented in the site quarterly status reports since the <br /> start of the remediation system operation <br /> ' As discussed in the above sections,the groundwater and soil vent gas treatment systems have <br /> operated efficiently over the project duration Because of the effects of the overall remediation <br /> system, the influent concentrations of both groundwater and soil vapor have diminished to <br /> nondetectable levels This has occurred over the life of the project and is presented in graphs of <br /> system performance in appendix D The graphs illustrate that the initial system groundwater and sod <br /> ' vent gas influent hydrocarbon concentrations were 1,700 ug/L and 3,500 ppmv, respectively, and <br /> diminished quickly over the first year of operation After the first year of operation, the hydrocarbon <br /> ' concentrations continued to decline, but at a slower rate Currently, both the groundwater and sod <br /> influent hydrocarbon concentrations are at asymptotic levels At this puncture, based on the above <br /> information, the continued operation of the remediation system will not remove any additional <br /> Imeasurable mass of hydrocarbons from the subsurface at the site The remediation system <br /> effectiveness has gone passed the point of diminishing returns <br /> 40 CURRENT SITE CONDITIONS <br /> ' Current site conditions are documented in the following subsections The conditions have been <br /> ' defined by evaluating the results of a recent soil boring program, of recent groundwater sampling <br /> data, and the operational data of the soil vapor and groundwater extraction treatment systems <br /> Definition of the current site conditions is necessary for comparison with the defined baseline site <br /> conditions Additionally, the chemical and physical parameters documented in this section were used <br /> ' 4202M 3 CR <br /> FLUOR DANIEL GTI <br />