After combustion takes place in our Energy-from-Waste (EfW) facilities, we are able to recover approximately 500,000 tons of both ferrous and non-ferrous metals from the remaining ash. This amount is enough steel to build more than five Golden Gate Bridges and sufficient aluminum for manufacturing more than two billion beverage cans. The recovery of metals provides Covanta with a growing revenue stream while providing important environmental benefits from the reuse of metals as an alternative to the mining and processing of virgin ore.
“Ash management is likely to be a continuing priority for Covanta. Another key issue of interest to stakeholders is metals recovery, to be considered separately from overall waste resource utilization.”
Michelle Mauthe Harvey
Director, Supply Chain, Environmental Defense Fund, Bentonville, Arkansas
Covanta has been recovering ferrous metals for decades, with the number of facilities capable of engaging in metals recovery steadily increasing over time. For example, our Hempstead EfW facility in Westbury, New York, which celebrated its 25th year of operation in 2014, has processed nearly 23 million tons of municipal solid waste and recovered 458,000 tons of ferrous metals.
New and improved systems, incorporating rare earth magnets and other technologies, have increased the amount of ferrous metal we can recover from the same waste stream. Since 2010, we’ve improved metal recovery systems serving 14 facilities.
More recently, we’ve been upgrading our recovery systems to capture non-ferrous metals like aluminum, copper and stainless steel. Since 2010, we have installed or updated non-ferrous metals recovery systems at 17 plants.
Putting Ash to Work
When EfW facilities combust waste, about 10 percent of the volume remains as ash. After metals are removed from the ash, we safely dispose of what is left over. Years of testing ash from every EfW facility in the country has consistently demonstrated that the ash is nonhazardous. Even so, we carefully manage our ash to minimize dusting and prevent migration of ash outside of controlled areas.
One way ash is used is as a daily cover for landfills. It exhibits concrete-like properties that cause it to harden once set in place. Use of ash for landfill daily cover reduces the need for virgin soils. Currently, approximately one-third of the ash from our facilities is beneficially reused as landfill daily cover.
“At Covanta, we have undertaken a number of creative projects to help dispose of ash after combustion, but there is much more that we hope to do. The question of ash management is high on our list of priorities, and we expect it to be a key focal point for us until we’ve found a comprehensive solution that satisfies all of our stakeholders.”
Vice President Environmental, Sustainability and Permitting, Covanta
Capturing Biomass Energy
Agricultural and forestry residues and clean urban wood wastes are an important source of renewable energy. When used to generate energy, these residues are widely recognized as having important benefits for the climate, by avoiding the use of fossil fuel-fired electricity and, particularly for agricultural residues, avoiding greenhouse gases and other emissions associated with landfilling and open burning. Covanta currently owns and/or operates seven biomass facilities, two in Maine and five in California.