Why Landfills Endure: Quantifying economic barriers to material and energy recovery from municipal solid waste in the United States

Abstract

Municipal solid waste (MSW) is a heterogeneous mixture of materials discarded by residential and nonresidential generators at end-of-life processing facilities for treatment and disposal. Conventional treatment methods reduce waste volumes through recycling via material recovery facilities, energy recovery via municipal solid waste incinerators, and biochemical conversion via composting. Even so, nearly 50% of total MSW generated in the United States was sent to landfills for final disposal in 2018 and almost half of all landfills currently in operation are expected to reach capacity by 2050. Waste planners seek to use developing resource recovery technologies like dry anaerobic digestion, gasification, and pyrolysis to narrow the gaps in end-of-life processing. Such technologies are posited to improve materials circularity and advance zero-waste landfill diversion goals by transforming residuals into electricity, fuels, and precursors to chemicals and fertilizers. However, despite demonstrated improvements to technical inefficiencies in waste valorization, numerous projects built on these technologies have failed to break through to commercial success. We investigate the contribution of regional and economic factors to the success of resource recovery projects through the lens of why landfills remain the predominant method of waste disposal. We build cost models of conventional and select developing treatment methods and use discounted cash flow analysis to estimate financial feasibility by local MSW compositions as reported in regional waste characterization studies.

Findings indicate that the most critical factor to sustainable operation is consistent supply of waste materials at the quality and scale that maximize production efficiency, which is not achievable without rigorous data monitoring of MSW composition. Conversely, dependence on waste volume rather than composition makes land disposal a uniquely flexible pathway capable of subsidizing the costs of resource recovery. Progress towards landfill diversion is economically linked to the opportunity cost of avoiding landfill utilization. Unless municipalities are able to introduce subsidies elsewhere in the waste management ecosystem through gate fees and credits, projects will fail where marginal net costs of diversion exceed the revenues lost from avoided landfilling. Targeted processing of organic wastes can facilitate an average diversion of 24% for the compositions surveyed and was found to be viable for composting and dry anaerobic digestion projects at low to negligible financial losses compared to landfilling.