Laserfiche WebLink
n - <br /> :. <br /> Ad endum o r. avian Knoly�4ENTO <br /> November 19, 1990 <br /> Page 4 <br /> Biodegradat}on <br /> The use of specific bacteria for the remediation of <br /> hydrocarbon-contaminated soil and groundwater is widespread. <br /> Often th+s involves the inoculation of sail with bacteria and <br /> nutrients; however, the necessary bacteria are generally present <br /> in the subsurface soil although at low populations. By <br /> increasing the a3vailable oxygen in the subsurface, it is feasible <br /> that the bacteria population will increase and consume the <br /> available hydrocarbons. <br /> The action of in situ bacteria is difficult to monitor. <br /> For this pilot study, it is proposed that soil samples will be <br /> analyzed for an aerobic population count from samples obtained <br /> during drilling. If the pilot study is expanded additional soil <br /> samples will be collected to determine if a bacterial population <br /> increase can be documented. <br /> Vapor Extraction Well Installation <br /> The four soil vapor wells will be installed in a manner <br /> similar to that used for ground water monitoring wells. At each <br /> well site, a borehole will be drilled using a truck mounted drill <br /> rig equipped with 10-inch outside-diameter hollow-stem augers. <br /> The well in the center of the area of contamination will be <br /> continuously cored to determine an accurate stratigraphy for the <br /> site. The additional boreholes will be sampling in the following <br /> method. <br /> Beginning at approximately 15 feet belcw the surface, soil <br /> samples will be obtained at five foot intervals using a <br /> decontaminated California-modified, split-spoon drive sampler. <br /> From each sampler, one sample will be selected for potential <br /> laboratory analyses. That sample will be sealed with foil, <br /> Plastic end caps, and tape and labeled with the appropriate <br /> information. The sample will then be stored on ice in an ice <br /> chest and may be delivered under chain of custody to the mobile <br /> laboratory on site. A second sample will be tested for <br /> temperature and soil vapor organic compound concentrations. <br /> When the borehole has been completed a vapor extraction well <br /> Will be installed. The well will be screened with four-inch <br /> inside-diameter Sch 40 PVC screen with 0.020 inch slots over the <br /> intervals which contained detectable hydrocarbon contamination. <br /> The wells will be completed to the surface with four-inch inside- <br /> diameter Sch 40 PVC blank casing. A coarse gravel pack will be <br />