Environmental implications of incineration of municipal solid waste and ash disposal

Owing to unsightliness and the threat of groundwater pollution, landfilling of municipal solid waste (MSW) is giving way to incineration in many communities. Environmental contamination from particulate and gaseous emissions containing heavy metals, polychlorinated dibenzodioxins (PCDD) and polychlorinated dibenzofurans (PCDF), polycyclic aromatics (PCA), acids and other compounds from such incinerators, as well as safe ash disposal, are of great concern. Concentration ranges of elements and organic toxicants in incinerator ashes, emissions and cooling waters are given. The literature is reviewed concerning the effects of incinerator operating parameters on emissions. Incinerators equipped with modern pollution control devices (electrostatic precipitators, fabric filters, dry scrubbers, spray towers) and operated at optimum temperature with sufficient oxygen, turbulence (mixing) and residence time for complete combustion appear to minimize ash, elemental, gaseous and organic emissions. Environmental aspects of MSW incineration are considered and reviewed. The presence of metals and organics in incinerator quench water and in leachates from ash disposed in landfills are reviewed, as well as their toxicity to fish. The behavior and effects of atmospheric emissions in soils and plants are discussed. Research on the effect of ash-derived PCDD and PCDF on hepatic microsomal mixed function oxidase activity and the immune system in laboratory animals is cited. The presence of metals, organics and mutagens in the incinerator workplace air and the possible effects of air-borne contaminants on inhabitants nearby is reviewed. Several studies dealing with human risk assessment of MSW incineration are cited.