Comparative life cycle assessment of solid waste management strategies

The “cradle-to-grave” human and environmental impacts of municipal solid waste (MSW) management practices are often evaluated using life cycle assessment (LCA) methods and tools. Many MSW LCA methods have been previously proposed, however, research suggests that the applicability of a given method is limited by geography. This paper sets forth the city of Austin, Texas as a fair representation of a “typical” U.S. city from the perspective of MSW treatment and disposal. It then describes the methods and findings of a comparative LCA of four different waste treatment scenarios in the city of Austin. In addition, the paper presents a unique approach, termed as orders of separation, to clearly establish and communicate LCA upstream and downstream considerations. The paper’s findings suggest that most life cycle impacts are from treating the MSW and that thermal treatment strategies are generally preferable to land filling strategies. Consequently, it may be justifiable to transport wastes longer distances to reach a thermal treatment facility. The findings of this paper will be of interest to solid waste managers and policy makers to compare different treatment options for U.S. cities.