An approach for estimation of contaminant release during utilization and disposal of municipal waste combustion residues

The use of appropriate leaching tests and leaching models can help to predict how constituents in municipal waste combustion residues will leach during either utilization or disposal scenarios. This paper presents a general approach for estimating constituent release from MWC residues under a variety of management scenarios through use of fundamental leaching, site specific design and regional climatic parameters. Leaching behavior is categorized as being controlled by either (i) constituent availability or solubility for percolation-dominated scenarios with loose granular residues, or, (ii) controlled by diffusion for flow around scenarios with compacted granular residues or monolithic products containing residues. Three broad scenarios involving either disposal or utilization are used to illustrate the approach. The scenarios are applied to bottom ash, combined ash and APC residue. In two specific cases pertinent to bottom ash utilization, field data are used to verify the approach. Field data are also used to verify the approach for disposal of combined ash. These methodologies hold promise for serving as a basis for evaluating and comparing potential environmental impacts from different management scenarios for combustion residues and for other waste materials.