Laboratory Study to Investigate Gaseous Emissions and Solids Decomposition During Composting of Municipal Solid Wastes

摘要

A materials flow analysis was performed for composting municipal solid waste (MSW) and specific biodegradable organic components of MSW. This work is part of an overall U.S. Environmental Protection Agency (EPA) project providing cost, energy, and materials flow information on different methods to reduce, recycle, treat, or dispose of MSW. This information will be used by managers to optimize MSW management. Calculating energy and material flows, emissions, and costs associated with different methods and mixes of methods for handling MSW or for different components of MSW will provide basic information to guide decisionmakers. Composting is aerobic decomposition of a substrate, in this case MSW or its components. The purpose of this work is to quantify and model energy and material flows into a typical compost facility and material flows out of it. This work required laboratory experiments because material flows in particular were not known for general MSW or its components. The results indicate that MSW (at 25% inorganics) and its three largest decomposable components (i.e., food wastes, mixed paper, and yard wastes) will lose 47, 66, 35, and 48%, respectively, of their dry weight upon complete composting. This will produce 730, 1,340, 560, and 800 kg of carbon dioxide (CO2) per dry U.S. ton of MSW, food wastes, mixed paper, and yard wastes, respectively. Corresponding ammonia releases are 0.42, 49, 2.4, and 5.4 kg per dry ton. Volatile organic compound (VOC) releases were quantified for 12 targeted VOCs, and additional VOCs were found but not quantified. The results are modeled for facilities accepting various combinations of MSW components (or MSW of various compositions).