| Summary: | The four papers of this dissertation explore themes related to waste prevention, the system boundaries, functional units and scale of life cycle assessments (LCAs) of municipal solid waste (MSW) management, as well as the transparency and consistency of the application of LCA methods. The first paper is a comparative analysis of the methodological choices and transparency of 20 LCAs of MSW that were recently published in peer-reviewed journals, and includes a comparison of their midpoint level impact values using statistical indicators. The second paper proposes a conceptual model, designated WasteMAP (Waste Management And Prevention), for evaluating LCAs of MSW which incorporate waste prevention. In WasteMAP, waste prevention through dematerialization is viewed as analogous to waste treatments so long as it does not affect the functional output (product services) of MSW-generating product systems. Papers 3 and 4 comprise the WasteMAP LCA case study. Paper 3 depicts product LCAs of wine and spirit packaging (conventional, lightweight and refillable, each type generating different quantities of waste) at the scale of the individual package and the municipality. At the municipal scale, the LCAs address impacts from the wine and spirit packaging supplied in the City of Toronto, Canada in 2008, and a waste prevention scenario which substitutes lighter weight and reusable containers. The lowest endpoint level impacts out of the five container types studied were associated with refillable containers and aseptic cartons. Paper 4 addresses the Toronto MSW management system and applies the WasteMAP model to allow for the comparison, on a functionally equivalent basis, of the LCA results of a reference scenario, based on 2008 data, with a scenario incorporating six types of waste prevention activities (prevention of unaddressed advertising mail, disposable plastic bags, newspapers, lightweight and refillable wine and spirit packaging, and yard waste). The findings highlight the benefits of waste prevention, and the relative significance of the decision to account for recycled content when modelling waste prevention. The endpoint level impact assessment results using the ReCiPe and Impact 2002+ evaluation methods are in keeping with the assumption in the waste hierarchy that waste prevention has a superior environmental performance.
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