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Geological rcclsaks lac. Page 10 <br /> B ioventing/Biosparging <br /> Pilot Test Work Plan <br /> ••• Project No.770.2 <br /> June 9,2006 <br /> 5.0 BIOSPARGING TEST <br /> Biosparging technology consists of injecting oxygen (air) into the saturated zone of the <br /> subsurface to promote biological degradation of petroleum hydrocarbons. The infrastructure <br /> required to test this method includes injection wells, a blower or compressor and monitoring <br /> points (wells) to determine radius of influence. <br /> 5.1 Injection Well Installation <br /> A single deep well will be utilized due to small lateral extent of the groundwater plume at the <br /> site. It is important to limit the air injection to prevent causing dispersion of the plume with <br /> excessive pressure. The sparging well AS-1 will be screened just below the static water table <br /> and will be placed in the vicinity of the most contaminated monitoring well- MW-5. (see <br /> Figure 10 for proposed well location). Figure 5 shows the proposed well AS-1 superimposed <br /> on cross section B —B'. <br /> The well construction details are included in the following table: <br /> low <br /> Ceramic diffuser Filter Pack Bentonite Cement <br /> Well Diameter 20—24" 3#sand Annular Grout <br /> (ft) Seal (ft) (ft) <br /> AS-1 V 70 - 72' 69 - 72' 67 - 69' 0 - 67' <br /> Placing the wells in this position will provide fresh oxygen through the most heavily <br /> impacted groundwater at the site. <br /> low <br /> Well installation P. � <br /> Prior to commencing work, encroachmentpermits and soil"boring/monitoring well permits <br /> .. will be secured and the SJC PHS/EHD will be notified.48 hours in advance. The subsurface <br /> will be cleared of underground utilities by notifying Underground Service Alert. <br /> The boring will be drilled using an 8-inch outside diameter continuous flight hollow stem <br /> auger as above. The borehole will be continuously logged to total depth. <br /> Soil cuttings will be containerized in DOT approved 55-gallon steel drums and held on site <br /> pending disposal. <br /> Well construction <br /> The monitoring wells will be constructed using 1 inch diameter PVC casing with flush <br /> threads. An 18 — 24" long ceramic diffuser will be procured for a sparge point. A #3 sand <br /> `r filter pack will surround and extend one foot above the sparge point. The filter pack will be <br /> surged to obtain maximum density. A two-foot transition seal will be installed above the <br /> .r <br />