ARCHIVED REPORTS XR0003056 - Laserfiche WebLink

Home Browse Search

Chevron Products Company 10 Former Chevron Station 9-5775, 301 W Kettleman Lane, Lodi, CA July 24,2000 0 Interim Remedial Alternative Recommendation • A combination of a SVE and a GWE system was selected as the most cost effective remedial alternative to mitigate subsurface impacts to remediation goals and to minimize further offsite migration of the dissolved plume and to reduce source SVE will remediate unsaturated soils by extracting soil vapor and introducing oxygen for biodegradation GWE will provide control of the dissolved MtBE plume to prevent further offsite migration and will provide for the removal of dissolved hydrocarbon constituents through extraction Interim Remedial System Installation An interim remediation system was mstalIed by G -R in June 2000 The SVE system consists of four SVE wells (VE -1 through VE -4) and 100 cubic feet minute (cfm) catalytic oxidizer The GWE system consists of one extraction well (EX -1), a submersible groundwater extraction pump, and three 2,000 -pound carbon vessels The system began operation on July 3, 2000 Currently, data is being collected from the GWE and SVE systems to determine the necessity for additional GWE and SVE wells CONCLUSIONS AND RECOMMENDATIONS • Based on the assessment activities performed to date, two water -bearing zones have been identified beneath the site A shallow water -bearing zone was reported within an approximate 5 -foot layer of primarily coarser -grained soils (silts and sands) at depths of approximately 55 to 65 feet bgs A deeper water -bearing zone of unknown thickness was reported within primarily fine-grained soils at depths of approximately 60 to 70 feet bgs and was encountered to the bottom of the borings at approximately 90 feet bgs A coarser -grained unit was encountered directly below the finer -grained unit in boring MW -12B This coarser -grained unit was also saturated and was encountered to the bottom of the boring at a depth of 90 feet bgs • A municipal water supply well is located approximately 350 feet southwest of the site To date, analytical data collected from this well since 1996 has indicated no impact by hydrocarbons or fuel oxygenates As previously reported, the well is screened from 210 to 500 feet bgs and has an annular grout seal to 108 feet bgs The majority of soil impact has been previously reported in the area of the former UST" Based on soil analytical data, the majority of soil impact is limited to onsite Groundwater flow within the shallow water -bearing zone has been reported to fluctuate between the south-southwest to southeast The lateral extent of hydrocarbons in the shallow water -bearing zone has been defined by wells MW -8A, -9, -10A, 11A, and 12A 077 41991 04319-5775PAR doe