This research was conducted in three sets of field-scale composting experiments. Also presented are two brief economic models that compare processing costs of an in-vessel system to a windrow biosolids and to a biopile treatment operation.; The first set of experiments quantified hydrocarbons, organic sulfur compounds, and ammonia produced by an in-vessel system composting sewage sludge. Cumulative hydrocarbons, organosulfur compounds, and ammonia gas emissions were compared to published emissions from two commercial windrow operations. For a similar dry mass fraction of sewage sludge, the in-vessel emissions were ten-fold lower for non-methane hydrocarbons, organosulfur compounds, and ammonia. Additionally, methane concentrations in the in-vessel exhaust gas were negligible, whereas the windrow systems generated 1.8-g to 26.6-g methane per dry-kg. In regions with stringent air emission regulations, a properly operated in-vessel system could overcome the need for exhaust gas treatment. The effect of C/N ratio on ammonia generation was evaluated, as was the variability of hydrocarbon emissions from batch to batch.; The second set of experiments compared in-vessel performance to a windrow and a static pile in remediating explosives-contaminated soil. Based on these experiments, preferred conditions for remediating HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) in soil were at saturated moisture content with infrequent mixing to promote reductive transformations. Operating under low moisture content and at a 50% soil mass fraction decreased HMX removal efficiency.; The third test set consisted of constructing and operating a 400-m 3 and a 1,000-m3 biopile to remediate soils contaminated with total petroleum hydrocarbons (TPH). The TPH removals were 62% and 77% after 7 and 27 months, respectively. Initial TPH levels averaged 1,550 and 3,200 mg/kg, and final average values were 590 and 740 mg/kg. Grinding and blending soil prior to treatment would have distributed TPH contamination more evenly and reduced agglomeration of TPH-saturated soil in which oxygen, water, and hydrocarbon transport were limited. Enhanced ex-situ soil treatment options for smaller volumes of contaminated soil (approx. 200 to 1,500-m 3) were proposed. An in-vessel system could provide periodic mixing and could sustain process conditions that approach the control possible in laboratory systems. Future research focused on validating an in-vessel approach is recommended.
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