Using Life - Cycle Analysis to Compare Solid Waste Management Alternatives Involving Recycling , Composting and Landfills

Introduction Solid waste management is an issue that must be addressed by every community in the U.S. The demand for waste management strategies that are protective of the environment has increased due to heightened environmental awareness and major evolution in both environmental policy and regulation over the last 20-30 years. Unfortunately, the quantities of waste that require management have also increased markedly over this period. Per capita generation of municipal solid waste (MSW) has increased from 2.7 lb/day in 1960 to 4.4 lb/day in 1998 (US EPA 1999). While increases in the quantity of waste recycled and composted have also increased over this period, the mass of MSW buried in landfills has increased from about 55 to 120 million tons per year due to increases in both waste generation rates and the U.S. population (US EPA, 1999). There are multiple alternatives for the collection, recycling, treatment and disposal of MSW including collection of mixed waste together with or separate from recyclables and yard waste, materials recovery facilities (MRFs) for recyclables recovery, yard and mixed waste composting, combustion, and landfills for MSW or the ash remaining after combustion. The total cost of solid waste management is influenced strongly by the particular waste management strategy adopted. For example, waste-to-energy facilities are more expensive than landfills in most regions of the U.S. and residential curbside recycling programs typically increase the cost of solid waste management above the cost of landfill disposal. While the costs of solid waste management alternatives are reasonably well understood, the environmental burdens associated with these alternatives are not. The objective of this article is to present estimates of the environmental performance of six alternatives for solid waste management that involve recycling, yard waste composting, organics composting and traditional and bioreactor landfills. Environmental emissions and total energy consumption associated with each waste management alternative are calculated using the techniques of life-cycle analysis (LCA) as incorporated in a computer tool developed by North Carolina State University in conjunction with the Research Triangle Institute and the USEPA. The scenarios considered are described in the following section, followed by a short explanation of LCA, some detail on the computer tool and then the results of the analysis.