ARCHIVED REPORTS_XR0002483 - Laserfiche WebLink

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CLEAkWA'T--ER G R O U P Environmental Services source There is anecdotal evidence of on-site personnel who observed significant hydrocarbon vapor release during subsurface road construction activities on South Fresno Avenue Feasibility Testing urpose Following the final site investigation activities in March 2000, quarterly groundwater monitoring was continued to examine trends in hydrocarbon concentrations and distribution It is evident from recent groundwater monitoring data that contaminant concentrations are generally consistent with cumulative analytical results, generally since the 1st quarter of 2000 It is therefore important to evaluate options other than natural attenuation for the reduction of contaminant concentrations Feasibility testing of several remedial technologies are recommended for their potential for successful remediation Subsurface conditions, contaminant type, and distribution of contaminants suggest that the following technologies may be successful • combined groundwater extraction and soil vapor extraction (GWE/SVE), • combined soil vapor extraction and air sparging (SVE/AS), or • a combination of all three technologies (GWE/SVE/AS) Proposed scope of works Before any feasibility testing can begin, one dual-phase test well will need to be installed to facilitate sufficient groundwater extraction and soil vapor extraction Also to be drilled and installed is one test point for air sparging The specification for each is described in the following sections Following the drilling and installation of the dual-phase test well and sparge test point, the feasibility testing will proceed in the following order • Step-interval tests in the newly installed test well to determine the most appropriate pumping flow rate for GWE • Pilot testing for SVE alone followed by combined GWE/SVE testing • AS testing combined with GWE/SVE ZB178C Workplan for remedial feasibility testing 5 August 2001