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Of all the limiting factors associated with active aerobic bioremediation, the primary limiting factor will be <br /> temperature. Typically, optimal temperature for average microbe replication is 75°F to 90°F. Activity will be <br /> reduced as temperatures vary from the optimal range. Expected site conditions will be between 55°F and 60°F <br /> and slower than optimal activity is expected. Since treatment is planned through the addition of water, <br /> microbes, oxygen and nutrients utilizing treatment ports, temperature will be manipulated to maintain more <br /> optimal conditions when possible as described below. <br /> During the treatment process, if it is identified that ground/surface water is impacted,an amendment or revision <br /> to the bioremediation plan will be conducted outlining the specifics of groundwater and surface water <br /> monitoring and remediation. <br /> III. Bioremediation Treatment Port Design <br /> For soils that cannot be excavated and transported offsite to disposal at South Canyon Landfill, HRL proposes <br /> to treat the impacted soils in-situ via infiltration of bioremediation treatment through a PVC infiltration piping <br /> gallery and gravity feed percolation. <br /> Three (3) 10-slot 2" PVC laterals will be installed horizontally in the bottom of the excavation at the release <br /> point of origin. The treatment system will be installed approximately 10 feet below ground surface (bgs), with <br /> each lateral extending approximately 25-30ft.The slotted PVC piping system will be placed on the southeastern <br /> and southwestern side of the excavation, and one lateral extending through the middle of the impacted area <br /> (See Figure 1). The horizontal laterals will come together at one focal point located on the southeast corner of <br /> the excavation but contain separate ports for flow control and isolation of the treatment lateral. <br /> The 2" PVC riser ports extending above ground will contain a butterfly valve and a threaded plug to prevent <br /> precipitation from entering the ports, as well as aid in preventing freezing of the bioremediation product. <br /> During construction of the treatment ports, modifications to the center lateral may consist of solid stem PVC <br /> with slotted 2" PVC pipe extending off the main line to increase the effective treatment area and additional <br /> underlying pathways throughout the impacted area. <br /> The treatment system will be backfilled with 3/4-inch washed gravel providing protection and preventing a <br /> compacted oxygen depleted environment(See Figure 2). <br /> Once the gravel is placed around the infiltration laterals, backfilling of the excavated area will occur with clean <br /> fill material from the surrounding area. Large marble blocks will be placed within the excavation adjacent to <br /> the PVC pipe for added support. Upon backfilling of the excavated area, CSQ will install a poly liner to serve <br /> as spill containment for the generator and fuel tanks. <br /> IV. Infiltration Trench <br /> Groundwater monitoring wells will be installed downgradient of the in-situ treatment system to monitor the <br /> effectiveness of the treatment process. If it is determined that the treatment application is not adequately treating <br /> areas downgradient or missing target areas, infiltration trenches can be installed to allow additional application <br /> of bioremediation product. <br /> Due to the location of this release and winter weather, as well as limited information currently available <br /> regarding the area of influence from the initial treatment, infiltration trenches would not be recommended until <br /> the spring/summer of 2020 when the soils and outside temperatures are more favorable to bioremediation. <br /> 2 <br />