Most ordinary household waste (i.e., garbage or trash) is classified as municipal solid waste (MSW) and is disposed of in MSW landfills. MSW consists of many different kinds of materials such as glass, plastic, paper, and metal, but the component of most interest for bioenergy and bioproducts is wood. The wood component of MSW consists of packaging materials such as wooden crates and pallets, durable materials such as furniture, and yard trimmings (mostly grass clippings and leaves, but also includes about 25% wood obtained from pruning and brush removal).
Data on the quantities of wood contained in MSW is limited and of variable quality. The Environmental Protection Agency estimated that in 2005, 245.7 million tons of municipal solid waste was generated and that wood and yard trimmings represented 5.7% and 13.1% of the total (by weight), respectively. The recovery rate for wood was low (9.4%); however, nearly 62% of the yard trimmings were recovered, mainly to produce compost.
Other studies estimate that between 18.9 to 29.5 million tons of wood waste are contained in MSW - but due to contamination or use in other applications, only 6.2 to 9.7 million tons could be available for bioenergy and bioproduct use.
Much of the wood waste is in a format not readily useable for bioenergy and bioproducts, and so must first be sorted and processed. When economic considerations (sorting, processing and alternative markets) are included, the estimated quantities of MSW wood waste available at less than $50/dry ton were only 7.3 million dry tons in 2005 and are projected to be 8.4 million dry tons by 2025.