Environmental sustainability assessment of the management of municipal solid waste incineration residues: a review of the current situation

Abstract

Incineration has become an attractive option for municipal solid waste (MSW) management, due to its several benefits. In fact, it allows volume and mass reduction of waste and energy recovery from MSW combustion. Nevertheless, MSW incineration (MSWI) produces three main types of residues: bottom ash (BA), fly ash (FA) and air pollution control (APC) residues, which require an adequate handling. BA is the most significant by-product from MSWI and is generally considered as non-hazardous waste. Instead, FAs are included as hazardous wastes because are characterised by high content of chlorides, heavy metals and organic compounds. The aim of this paper was to examine the characteristics of MSWI solid residues, the management and reuse of these wastes and their environmental assessment from a life cycle perspective. It was noted that the main components that make up the residues are lead and zinc as well as oxides, mainly CaO, SiO2 and Al2O3. Furthermore, it is necessary to take into account the presence of PCDD/F which characterised FA and APC residues, mainly due to chlorine content. Chemical and physical properties of those residues make possible their reuse as construction material, as adsorbent, as well as in geotechnical and agricultural applications. Nevertheless, several studies have demonstrated that a drawback of the reuse of MSWI residues is the existence of heavy metals in elevated concentrations which may affect the environmental quality. In this regard, many studies were aimed to assess the environmental impact related to the introduction of MSWI residues as secondary material in several fields of application.