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fraction of hydrocarbons and can occur chemically, <br /> photochemically, and/or microbially. <br /> The basic landfarm operations are as follows: <br /> o The area which will be used for landfarming is prepared by <br /> removing surface debris, large rocks and brush. <br /> o The area is graded to provide positive drainage and sur- <br /> rounded by a soil berm to contain run-off within the <br /> landfarm area. <br /> o If necessary, the pH of the soil is adjusted with agricul- <br /> tural lime to provide a neutral pH. At this pH, metals are <br /> not highly mobile and bacterial processes and growth are <br /> supported. <br /> t <br /> o Agricultural fertilizer is added if the site is deficient in <br /> nutrients such as nitrogen, phosphorous, potassium and trace <br /> elements. Fertilizer is also added as needed during the <br /> biodegradation process. <br /> o The soils containing petroleum products are spread uniformly <br /> over the surface of the prepared area. It is important to <br /> distribute the hydrocarbons over the landfarm area as uni- <br /> formly as practical to minimize localized loadings. <br /> o The landfarmed material is incorporated in the top 6 to 8 <br /> inches of soil with a tiller, disc harrow, or other plough- <br /> ing device. The soil must be well mixed to increase contact <br /> between the organics and microorganisms and to supply air <br /> for the aerobic biological degradation process. <br /> Composting is similar to landfarming, as both processes rely on <br /> the destruction of organic compounds through microbial metabo- <br /> lism. The destruction of hydrocarbons using composting opera- <br /> tions is usually not compete so landfarming is frequently re- <br /> quired as a follow-up step. Generally, composting is practiced <br /> on a combination of municipal refuse and sewage sludges for <br /> eventual land application and soil amendment. <br /> The costs associated with on-site landspreading of the soils are <br /> as follows: <br /> Excavation (8000 yd3) 40, 000 <br /> Transport and Organic Matter 111000 <br /> Site Backfill & Resurface 80, 000 <br /> Misc. (Discing and Manpower) 45, 000 <br /> Monitoring and Sampling 30. 000 <br /> $206, 000 <br /> Contingency (20%) 41. 200 <br /> Total Estimate $247 ,200 <br /> 15 - <br />