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soils may be obtained through the application of a number of <br /> aerobic (oxygen utilizing) soil biodegradation procedures, i.e. : <br /> Forced air composting <br /> Static pile aeration <br /> Windrowing <br /> Thin-spread landfarming <br /> Forced air composting has been utilized during periods of <br /> inclement weather and under circumstances where space for <br /> treatment is limited. It involves the thorough mixing of <br /> contaminated soil with compost. . .this material having proven <br /> 'r to be a superior bulking agent, and source of non-pathogenic <br /> hydrocarbon utilizing bacteria and fungi, nutrients, minerals, <br /> and moisture. The amended soil is then formed into large, <br /> y quadrilateral beds through which slotted piping is placed. <br /> The piping is then connected to pumps which draw air through <br /> the treatment beds in order to maintain adequate supplies of <br /> oxygen within. Beds may also be covered to regulate temperature <br /> and protect against extreme weather conditions. <br /> Static pile aeration is a process similar to forced-air, however, <br /> no piping is placed within the bed as periods of cooler weather <br /> create conditions in which passive air flow into the bed provides <br /> adequate aeration as a result of the upward movement of biologi- <br /> cally heated air drawing the cooler ambient air into the sides <br /> of the beds. <br /> Windrowing is a process which utilizes a specially modified <br /> soils mixing machine to construct six foot high beds of amended <br /> soil. The beds are turned periodically to maintain aerobic <br /> conditions and break down clayey soils. This process is believed <br /> unique to local projects and has provided superior degradation <br /> rates. <br /> Thin-spread landfarming is the most commonly used soils <br /> - bioremediation protocol. Here, contaminated soil is spread . <br /> thinly (to a depth of approximately 9 inches) to permit passive <br /> aeration. <br /> Yr <br /> In all cases, the treatment beds are carefully monitored and <br /> sampled to provide for adequate soil permeability, pH, moisture, <br /> and nutrients by determining the rate of hydrocarbon degradation, <br /> the formation of degradation intermediate compounds, and levels <br /> of nutrients, and moisture. Final .sampling and analysis is <br /> in accordance with Regional Water Quality Control Board and <br /> Bay Area Air Quality Management District guidelines with target <br /> levels for remediation being below the practical detection limits <br /> for petroleum hydrocarbons in soil (i.e. less than 10 parts <br /> per million) . <br /> .r <br /> .V <br /> �1 <br />