The construction of new buildings and structures and the renovation, remodeling, and demolition of existing buildings and structures generate a substantial amount of waste materials. Some of this material is recycled, but most is disposed of - typically in Construction and Demolition (C&D) landfills or Municipal Solid Waste (MSW) landfills. C&D wastes are composed of numerous materials such as concrete, drywall, asphalt, and metal, but the component of most interest for bioenergy and bioproducts is wood. Wood is usually the largest component of construction and renovation wastes, while concrete is usually the largest component of demolition wastes.
Construction wastes can be more easily sorted at the generation site (source separation), while demolition wastes are more difficult to sort. Additionally, construction wood wastes are often cleaner and less contaminated than demolition wastes, and thus are more readily useful for bioenergy and bioproduct uses. Renovation wastes are intermediate in sorting difficulty, because remodeling activities often include both new construction and demolition or replacement of existing materials.
Construction and demolition data is limited and often of questionable quality. According to an EPA study, an estimated 135.5 million tons of C&D waste were generated in 1996. Concrete, asphalt, metals, and wood were the materials most frequently recovered.
Other studies estimate that 9 to 11.6 million tons of construction and renovation wood wastes, and 27.5 million tons of demolition wood wastes are generated annually. Due to contamination and alternative uses, an estimated 6.9 to 8.6 million tons of the construction wood waste and 9.6 to 11.2 million tons of the demolition wood waste could be available for bioenergy use.
When sorting, processing and other costs are included, the estimated quantities of C&D wood waste available at less than $50/dry ton were 25.8 million dry tons in 2005 and are projected to be 29.4 million dry tons in 2025.