Life Cycle Assessment as a decision support tool in the Waste Management sector: a Critical Review

The purpose of the paper is to present the most recent studies, published in the leading scientific journals, concerning with the application of the Life Cycle Assessment methodology in the solid waste management sector. First of all, there is an introduction of the current trends of the life cycle analysis in this field, coming from a detailed survey on the LCA studies published in the last five years in the main scientific journals dealing with LCA methodologies and waste management. The methodology is to identify and describe, for each article, the aim and purpose, the chosen approach, the data and models used, the results obtained and finally the conclusions. For a greater clarity the literature review is made by dividing the LCA studies into different areas: studies of the solid waste management in a broader sense, studies on thermal treatment of waste, studies of specific fractions of waste and studies related to specific processes. After a presentation of the main common characteristics of every category of articles, a summary is given in order to highlight some common suggestions in the conduction of a life cycle assessment study, coming from this analysis, according to the different aspects: typology of the study (namely if it is a single process-oriented analysis rather than at strategic level), methodology (avoided impacts approach, hypothesis and assumption, data) and results (including the main remarks coming from the life cycle assessment). As a result the literature review shows that conducting a LCA study in the waste management sector is a still time demanding and complex task, because of the complexity of the systems and the different aspect that have to be taken into account. To conclude some remarks are given on how to perform an LCA study in this sector, with regard to the system boundaries (need to include as much operations as possible, namely, collection, transport, typology of garbage bins), data (prefer site-specific data, including a waste analysis in different times during a year in order to define a medium composition), functional unit (which should be accurately defined in accordance with the scope of the study, considering the possible future variations), hypothesis (which should be accurate with special regard to the National energetic mix, the quality of the waste) and finally methodology (optional step in LCIA phase, sensitivity analysis, including economical considerations).