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When kept free of toxic components, the biodegradable fraction of municipal solid waste (MSW) may be decomposed by aerobic or anaerobic composting and the residues either disposed of by land application or marketed as compost. Anaerobic composting is more economic because it effects similar conversion, does not require mixing or aeration, and produces the valuable energy product methane. This paper describes technical performance and systems analysis of a novel sequential batch anaerobic composting (SEBAC) process for treatment of high solids wastes that employs leachate management to provide organisms, moisture, and nutrients required for rapid conversion of MSW and removal of inhibitory fermentation products during start-up. The results of 19 trials with this system operated at 55°C and total residence times of 21 or 42 days exhibited about 50% conversion of organic matter with a methane yield of 0.2 m3 kg−1 volatile solids. The process was reliable and stable. A systems analysis showed that tipping fees employing this process were in the $30 per ton range and that economics were highly sensitive to biodegradability of feedstock and residue use options; they were relatively insensitive to process kinetics and leachate recycle rate. This process can be applied to in-vessel or controlled landfill designs.

A novel process has been developed and evaluated in a pilotscale program for conversion of the biodegradable fraction of municipal solid waste (MSW) to methane via anaerobic composting. The sequential batch anaerobic composting (SEBAC) process employs leachate management to provide organisms, moisture, and nutrients required for rapid conversion of MSW and removal of inhibitory fermentation products during start-up. The biodegradable organic materials are converted to methane and carbon dioxide in 21-42 d, rather than the years required in landfills.

Conversion technologies (CTs) utilize thermal or biological processes to convert municipal solid waste (MSW) or Material Recovery Facility (MRF) residuals into useful products, such as electricity, fertilizers, and chemicals. These technologies, such as pyrolysis, gasification, and anaerobic digestion are very different from conventional waste-to-energy (WTE) technologies for MSW. CTs can provide greater efficiency and environmental benefits compared to WTE, and environmental and societal benefits compared to landfilling.

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