Construction and demolition debris recycling: Methods, markets, and policy.

摘要

Construction and demolition (C&D) debris is generated from the construction, renovation, or demolition of a structure. This waste stream has become a concern across the United States. Recycling is often seen as a solution, but questions remain regarding the size of the debris stream, market availability for recycled waste materials, the environmental impacts from management methods, and how to encourage recycling.;A materials flow analysis was performed to estimate the amount of C&D debris generated from the amount of construction materials consumed each year. It found that approximately 0.8--1.3 x 109 Mg were generated in 2002. While this type of estimate accounts for materials consumed, current assumptions used may result in larger amounts than the amount actually generated. The size and location of recycled C&D debris materials markets were investigated to determine if C&D debris recycling programs across the US are possible. Sufficient market capacity exists for concrete and wood, but there is not sufficient market for asphalt shingles and drywall faces competition from other materials. A life cycle assessment approach was used to compare environmental impacts from the various methods of C&D debris management, including disposal, recycling, and incineration. Recycling was found to be the most beneficial method of management for concrete, drywall, and asphalt shingles when comparing global warming potential, human toxicity potential, acidification potential, and abiotic depletion potential. The best management method for wood was incineration. Policies that encourage C&D debris recycling around the country were compared. All local policies were successful, with degrees of success and costs greatly dependent on regional characteristics. State recycling goals, however, had little impact on increasing recycling.;Finally, a case study was performed for waste concrete in Florida to determine the amount that is generated (40--61 x 10 6 Mg), the market availability, the management option with the fewest environmental impacts, and the best policy to encourage concrete recycling. Sufficient market exists to recycle all concrete in Florida. Recycling was found to have the fewest environmental impacts in most areas of the state. Policies that required contractors to recycle a percentage of their waste stream were the best for Florida.