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Md GeotogicaI ndvtics Inc. Page 6 BioventingBiosparging � Pilot Test Work Plan ^�1\ Project No.770.2 r June 9,2006 r..l parameters. ' The objective of the pilot tests would be to obtain enough data to design a treatment system to address the entire soil and groundwater plumes. If the permeability of the site is adequate for these technologies, then GTI anticipates augmenting the injected air with pure oxygen as well to promote biodegradation. .r GTI also proposes to perform a soil vapor extraction pilot test utilizing higher vacuum pressures (up to 26" Hg vacuum) than used with standard SVE. This is similar to dual phase extraction technology but without the intent of extracting and treating groundwater. The SJC J PHS/EHD previously denied our proposal to test this technology based on its inapplicability to diesel fuel. However, the CPT investigation indicates that some lithologic units of greater permeability are present that might benefit from this technology. The soil micro-fractures structures also may facilitate extraction through silty and clayey soils. With the installation of several new wells and the existing wells that can be used to test high vacuum vapor extraction, it will also be worthwhile to test this technology during the pilot test mobilization. `r GTI has used this technology in a pilot test at another gasoline/diesel contaminated site with success at removing diesel from the subsurface. A second rational for performing the dual phase extraction test is that both the bioventing and biosparging tests outlined below could cause a spread of the contamination in heterogeneous ,r soils. By following these tests with one week of dual phase high vacuum extraction we can /� reverse any dispersion process and draw the diesel back to the core of the plume for extraction. This is especially true for the groundwater plume that is centered on well MW-5. 5r'' If bioventing/biosparging are selected as remedial options for this site, the injection & extraction process will be switched between wells to control plume spreading action. •. Details of the pilot test(s) are provided in the following sections. Note: all remediation well borehole locations will be continuously cored to identify units of greater permeability in order to confirm the CPT data. 4.0 BIOVENTING PILOT TEST tow Bioventing technology consists of introducing oxygen (air) into the subsurface by using either injection or extraction wells to promote biological degradation of petroleum hydrocarbons. The infrastructure required to test this method includes injection/extraction wells, a blower or compressor and monitoring points (extraction wells) to determine radius of influence. 4.1 Injection/Extraction Well Installation A well set consisting of a shallow and deep air injection/extraction wells will be utilized due to the heterogeneity of the soils at the site. The shallow wells will have a screened interval to intercept the sandy unit at 40 — 45 feet bgs in the release area. The deeper wells will be screened deeper to test the permeability of the clayey/silty units at 55 — 60 feet bgs. The r V