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to accelerate biodegradation of hydrocarbons (bioremediation process). The <br /> objective of the treatment process is to biodegrade the hydrocarbons to levels <br /> appropriate for landfilling. After the contaminated soils have been adequately <br /> treated, the soil can be used for daily cover, intermediate cover, or foundation <br /> layer for the closure cap. If necessary, the treated soils can be disposed in a <br /> Class II or Class III WMU. <br /> Although there are currently;no Land 1watment Units (LTUs) at the site, LTUs have <br /> been constructed in the--past and may be utilized in the future. LTUs for <br /> contaminated soil are permitted within WMU G-North,�or G-South. The units are <br /> approximately 40 feet-wide y{500. ng.,;.:he nurnber of operating LTUs=at <br /> any given time will vary according to the market need for the soil treatment <br /> process. Previously constru --LT ,fiave- d-of.a, it polyvinyl°cloride <br /> (PVC) liner covered with a 6-inch-minimum thickness layer of sand and gravel, an <br /> 18-inch minimum thickness layer of compacted clay, and a 6-inch-minimum <br /> thickness layer of a sand and gravel buffer zone...>A.,JaW.of:conta>tr>linated.soil <br /> approximately 18 inches thick is placed within each LTU for treatment. <br /> Berms contain stormwater within the LTUs, and a drainage system removes storm- <br /> water that accumulates. The surfaces of the LTUs will be sloped so that excess s <br /> rainwater drains to a storm tank. Waterstored in.the.:tank.will.be,.used.for..soi1 <br /> moisture control during the treatment process or pumped to the leachate <br /> evaporation pond. <br /> A monitoring system has been designed to test the soils to ensure the efficiency of <br /> hydrocarbon biodegradation. Soils in the,.LTUs will J � ed-'regularly.to <br /> evaluate and manage the key treat tparameters such as soilmoisture, soil pH, <br /> soil nutrient levels, and air temperature. Following treatment, the soil will be <br /> analyzed to determine if the petroleum hydrocarbon concentration meets the.level <br /> acceptable for use as alternative cover or foundation material, or disposal. <br /> Each LTU will have a lysimeter at the low point for leak detection. The lysimeters <br /> monitor moisture in the vadose zone directly beneath the drainage system and are <br /> checked on a quarterly basis. <br /> These treatment units may also be used to treat other nonvolatile organics that are <br /> suitable for bioremediation such as PNAs. <br /> Forward Landfill JTD 6-9 <br /> L:\AI I ied\2000.193\Reports\finaljtd:Sec-6.0:08/20/01 <br /> BRYAN A.STIRRAT 6 ASSOCIATES <br />