ARCHIVED REPORTS_XR0008413 - Laserfiche WebLink

Home Browse Search

I 18 February 1997 AGE-NC Project No 95-0104 IPage 21 of 22 well will also facilitate proposed ground water remediation at the site (see Section 8 2) After each 6 months of operation, the thermal oxidation unit should be analyzed for efficiency If necessary, an activated carbon SVE system should be installed to continue the remediation Ito acceptable levels Operation of the SVE system at the site should be capable or removing between 80 and 90 percent of volatile contaminant by volume 9 A Remedial Action Work Plan (RAWP) should be prepared detailing the proposed SVE system 1 82 REMEDIATION OF HYDROCARBON-IMPACTED GROUND WATER Ground water monitoring at the site has indicated that wells MW-4 through MAV-6 are down-gradient wells High concentrations of dissolved hydrocarbons have been consistently detected in VW-1 An rn-situ remediation method would be more effective, from a cost and operation perspective, over a "pump and treat" method Both in-situ methods (air sparging/soil vapor extraction and • bioremediation) described in this CAP could be effective to remediate the site However, based upon limited regulatory acceptance and uncertain monitoring requirements, in-situ bioremediation of ground water may not be the most cost-effective remedial alternative for the site Remediation of impacted ground water in the"core" area should be conducted concurrently with soil remediation to prevent re-contamination of remediated soil In-situ air sparging/vapor extraction appears to be a viable alternative for remediation of both soil and ground water in the vicinity of the former UST location The system used for soil vapor extraction could also be used for the air sparging/extraction system A sparging/extraction system will also have a secondary effect of bioventing and increasing the natural degradation rate Combined with SVE, the IAS method mechanically strips hydrocarbons without the addition of any chemicals or microbe solution into the environment It is a better known and more widely accepted method of volatilizing hydrocarbons As IAS has few, if any, adverse environmental effects, it is likely to be more readily approved for implementation by regulatory agencies A 12- to 30-month remediation period can be expected to reduce concentrationsibelow State of California drinking water standards Ground water remediation alternatives, estimated durations and associated costs for the site are summarized on Table 5 In summary, AGE has the following recommendations for remediation of hydrocarbon-impacted ground water at the site A compressor or blower-driven IAS system should be installed at the site concurrently with 1 I