Windrow Composting Engineering/Economic Evaluation

Abstract : A conceptual level development of the use of composting technology for the treatment of explosives-contaminated soils and sediments has been conducted. These soils and sediments occur at a variety of Army ammunition plants (AAPs) and Army depots (ADs) as a result of post-industrial activities associated with munitions production. Previous investigations, including recent USAEC field demonstrations, have shown that composting can significantly reduce explosives levels in contaminated soils. This report presents a conceptual level facility design, including construction and operating requirements, and an economic evaluation for a windrow composting facility. System descriptions and costs are also presented for aerated static pile and mechanically agitated in-vessel composting technologies. All three composting technologies demonstrated cost savings versus incineration for comparable remedial project sizes. The 'treatment only' windrow composting cost for treatment of 20,000 tons of explosives-contaminated soil in a 5 year period was estimated to be $187 per ton of soil. An economic sensitivity analysis was conducted to determine the effect of project duration (1, 3, 5, 8, and 10 year periods for 20,000 tons of soil) and facility size (2,000, 5,000, and 10,000 tons of soil processed in 2 years). It was found that increasing treatment period beyond 3 years offered little economic benefit. treatment. -BKA