An international perspective on the characterisation and management of residues from MSW incinerators

Fully integrated municipal solid waste (MSW) management strategies around the globe include the use of incineration, either with or without energy recovery. During the late 1970ʹs and early 1980ʹs, the practice of incineration was subjected to increased scrutiny due to concerns over air emissions. As a result, the industry quickly moved to improve the design, operation and air pollution control systems of MSW incinerators to the point where emissions from modern, well operated and well maintained incinerator systems are no longer considered a threat to human health or the environment. This has resulted in a shift of concerns from air emissions to the incinerator residues. Many of the concerns regarding the disposal of MSW incinerator residues have become controversial in nature, mostly due to the broad scope of the factors influencing ash characteristics (such as MSW composition, incinerators technologies and operation), the fragmented database, the heterogeneity of the residues, and uncertainty over the long-term behaviour of the residue in the environment. Recognising there was a need to compile and evaluate the available information, the International Ash Working Group (IAWG) was established to conduct an in-depth review of the existing scientific data and develop a state-of-knowledge treatise on MSW incinerator residue characterisation, disposal, treatment and utilisation.