Typically, evaluations of the environmental performance of municipal solid waste (MSW) management systems involve crude measures that are subjective in nature. The most common such measure is the recycling rate—the percentage of MSW that is separated from the waste stream for materials recovery. While useful as a rough estimate of the performance of cities, materials recycling is not the only way to conserve resources. Energy recovery—from waste to energy (WTE) power plants or landfill gas to energy systems—also contributes to improved environmental performance. The principal objective of this thesis was to quantify the environmental performance of municipal waste management systems by introducing and utilizing a new metric, the resource conservation efficiency (RCE). RCE measures the lifecycle energy efficiency of materials and its value depends on the recyclability of the material as well as the method cities choose to dispose of non-recyclable materials.

To verify the validity of RCE as an environmental metric, a life cycle impact assessment (LCIA) was performed. It was shown that the cumulative energy demand for different materials correlates strongly with EcoIndicator 99 scores, a common LCIA environmental evaluation tool. This correlation demonstrates the validity of using the RCE not only as a measure of energy efficiency, but of "environmental efficiency" as well.

In addition to the development of RCE, a new method of acquiring and organizing US national MSW data was developed and described. The resulting Municipal Solid Waste Database allows for tonnage-based waste flow measurement that is used to analyze important US states such as California, where it is discovered that—though recycling rates have steadily increased over the years, disposal rates have remained relatively constant after an initial decline. Data collected in the development of the database is used to perform a case study comparing two American cities' (Honolulu and San Francisco) waste management systems using RCE. The results show that a combination of recycling and WTE is the most environmentally efficient way to manage MSW. More specifically, San Francisco would be much better served by building a WTE plant to handle its non-recycled waste than by expanding recycling. Honolulu's best course of action, however, would be to increase recycling to be commensurate with San Francisco's rates.

Additionally, in the search for an adequate life cycle metric, the statistical entropy method for quantifying the extent to which metals are diluted or concentrated in waste management systems was extended to account for carbon. This proved to be a useful measure of the global warming effects of different waste management strategies, but not as effective as the RCE metric, as an overall systems assessment tool.