ARCHIVED REPORTS XR0010226 - Laserfiche WebLink

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Former Discovery Chevrolet June 5, 1998 Tracy, California Corrective Action Plan r The most economical method of treatment and disposal would be by discharging the treated water to the to al storm or sanitary sewer system. Preliminary costs for the permitting, extraction, onsite treatment, and disposal of groundwater to the local sanitary sewer system are estimated to be approximately $3,000 to $4,000. Assuming approximately 1,000 gallons of groundwater would be extracted from the excavation, the preliminary additional costs for the transporting and disposal of the groundwater to a TSD facility are estimated to be approximately $6,000 to $8,000. The preliminary total cost for this groundwater remediation alternative estimated to range between approximately $9,000 to $12,000. 5.2.2 Alternative No. 2: (Groundwater) 5.2.2.1 Passive Remediation As previously discussed in the PAR, after excavation of the hydrocarbon-impacted soil, passive remediation of the groundwater would occur beneath the site. Passive (or intrinsic) remediation involves monitoring of groundwater to determine whether natural biodegredation, volatilization, or dispersion of petroleum hydrocarbons is occurring. The effectiveness of passive remediation is indicated by a decrease in concentrations in groundwater through time. It appears, from the cumulative groundwater quarterly monitoring analytical results that passive remediation has been occurring at this site. Bioparameters previously monitored at the site in 1996 and 1997 indicated that intrinsic biodegradation is an active method of ongoing remediation beneath the site. This method of remediation would be very economical. Preliminary costs for two episodes of groundwater monitoring to evaluate the effectiveness of passive remediation are estimated to be approximately $2,500. 3001-21.cap 14 HORIZON ENVIRONMENTAL INC.