Energy from Municipal Solid Waste

This paper presents an overview of the solutions available for obtaining energy from municipal solid waste. Special waste is not taken into account because of its extreme variability of characteristics from region to region and from type to type. On the contrary, municipal solid waste shows aspects useful for a more homogeneous analysis of international interest concerning the exploitation of its energy content. The first part of this paper deals with the evolution of the interest towards energy recovery from municipal solid waste. The analysis is performed at international level, but a zoom is presented referring to European Union. The second part of the paper concerns the energy availability taking into account the dynamics of qualitative and quantitative composition of municipal solid waste. The third part analyses the role of selective collection in the frame of energy recovery. In this case it is pointed out how food waste selective collection can change the approach of the biogas exploitation: from a landfill based concept (with sanitary landfill seen as a bioreactor) to a reactor based scenario (where the anaerobic digester allows collecting 100% of the biogas generated). The fourth section of the paper concerns the trend in residual municipal solid waste exploitation, taking into account the effects of the European Union directives on the energy recovery strategies and the role played by the Directive 1999/31/CE (a compulsory pre-treatment makes less interesting the option of landfilling, moving the energy exploitation of residual municipal solid waste towards thermal treatments). Finally, a section of this paper concerns a case-study that offers a vision on how much anaerobic digestion and thermal treatments can support the energy demand of a citizen.