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Report of Composting Site Information <br /> Tracy Material Recovery Facility and Transfer Station <br /> 30703 S. MacArthur Drive, Tracy, Ca. 95377 <br /> automatically controlled per operator-chosen set-points. The system exhaust air is <br /> scrubbed in a biofilter constructed of wood chips in the case of negative aeration, and <br /> passes through the layer of finished compost and/or compost overs in the case of <br /> positive aeration. The aeration rates can be set very low to conserve moisture and fan <br /> power, without releasing odors. Prior to removing the cover the aeration is increased to <br /> lower temperatures and raise oxygen levels; this greatly diminishes the potential for <br /> odor releases. The use of an aeration floor facilitates implementation of aerated static <br /> piles. <br /> Similarly with the elongated and compressed windrows, two types of geometries are <br /> available for the aerated static pile; elongated and extended. <br /> Elongated Aerated Static Pile <br /> For the elongated aerated static pile, the material is formed into trapezoidal-shaped <br /> piles of approximately 30 feet wide, 15 feet high, and 70 feet in length. Piles are <br /> separated by a narrow access area to facilitate loading, monitoring, watering, moving, <br /> and turning. Elongated piles may also be formed within concrete-walled bunkers of <br /> similar size for easier materials management. <br /> Extended Aerated Pile <br /> To make more effective use of available space, another pile configuration has been <br /> developed called the extended aerated pile. Studies indicate that the area required for <br /> an extended pile is about 50% less than that for an elongated static pile. Extended piles <br /> consist of individual cells that are stacked against each other. Cells of new feedstock <br /> are constructed in one pile, and cells of nearing mature compost are placed in other <br /> piles. Extended aerated static piles also increase the emissions control achieved with a <br /> layer of finished compost as the adjacent cells of feedstock support the finished cover <br /> layer of the adjoining cell, minimizing sloughing of the compost layer. <br /> Cover Systems <br /> The synthetic ASP cover is designed with straps for handling and securing it and may <br /> be placed and removed manually or with mechanized cover-rollers. The cover may be <br /> held in.place by the aeration system which operates with negative suction that holds it <br /> firm against the pile or, in the case of positive aeration, use of perimeter weight at the <br /> base of each ASP. The impermeable cover over the ASP eliminates rain percolating <br /> through the pile and therefore reduces the total nutrient load found in the facility run-off. <br /> Proper grading of the site is maintained to limit intrusion of storm water around the <br /> "sealed" edge of the cover. <br /> Alternatively, a layer of finished compost or compost overs with a minimum thickness of <br /> 6 inches can be used to minimize storm water infiltration due to its absorptive capacity, <br /> and reduce air emissions by oxidizing gaseous compounds. The compost cover layer is <br /> incorporated into the feedstock when the pile is turned. With either a compost cover or <br /> an impermeable plastic cover, the system could potentially be operated under either <br /> negative or positive pressure depending upon the type of synthetic cover technology or <br /> which phase of composting (active or curing) a particular batch is undergoing. <br /> 14 <br />