Waste-to-energy residues - The search for beneficial uses

In the U.S., about 28.5 million tons of municipal solid waste are combusted annually in waste-to-energy facilities that generate 25-30% of ash by weight of the MSW feed. Since some residues were found to contain high levels of lead and cadmium prior to the 1990s, they were commonly associated with environmental pollution. However, for the last years nearly all ash samples have been tested non-hazardous. Research on the beneficial use of combustion residue has been conducted for the past few decades yet the actual ash reuse rate in the U.S. has remained close to 10%. Currently most of the ash is landfilled at considerable cost to the waste-to-energy industry. A consortium of researchers at Columbia University, the State University of New York at Stony Brook, Temple University, and other institutions seeks to develop and to advance the beneficial uses of combustion residues, such as in construction materials or remediation of contaminated abandoned mines and brownfields. This paper describes the search for beneficial use applications and provides an overview of the first year of this consortium.