Economic Feasibility of Drying Municipal SolidWaste Combustion Residue

Incineration of municipal solid waste MSW is increasing in many parts of the world. Waste incineration creates an ash residue that must be disposed of, typically in a solidwaste landfill. The ash is often waterquenched after incineration and may contain up to 50% moisture by weight. This moisture increases the weight of the ash sent to the landfill and the leachate load placed on the landfill's leachate collection system. In this paper, current literature on MSW ash is reviewed, current ash handling practices are outlined, and the economic feasibility of ashmoisture reduction schemes are investigated. Electric heating of the quenched bottom ash is shown to be an economically feasible scheme for moisture reduction. For current cost levels, the net yearly benefit may be as high as 1,200,000 for a typical 500 tons per day TPD plant. Further research and pilot plant studies are necessary to determine the optimum dryer type and configuration for maximum benefit.