Ash Testing
Waste-to-energy facilitiesuse combustion to convert trash into clean, renewable electricity. The combustion process produces an ash residue disposed of in a conventional landfill.
In accordance with federal law, waste-to-energy ash is tested to ensure it is non-hazardous. The U.S. Environmental Protection Agency (EPA) developed an aggressive test called the Toxicity Characteristic Leaching Procedure to determine if metals will leach from the material. If metals leach in amounts greater than a fraction of a percent, the ash is considered hazardous. Years of testing ash from every waste-to-energy facility in the country have proven that ash is safe for disposal and even reuse. Waste-to-energy ash consistently passes the EPA test, despite the fact that the test greatly exaggerates the potential for metals to leach from ash.
While landfill wastewater is regulated as an industrial discharge, test results and measurements taken from operating ash landfills show the levels of metals present in the actual ash leachate are most often below the significantly more restrictive drinking water standards and far lower than the EPA toxicity criteria.
When trash is combusted in a waste-to-energy facility, the resulting ash represents about 10 percent of the volume of the original trash. Metals, such as iron, steel, copper and zinc are recovered from the ash at the facility and sent to be recycled into new metal products, leaving a residue that looks a lot like wet cement. This residue actually has physical properties similar to construction mixtures such as concrete. After a short time, the ash "cures" and resembles concrete.
But disposal is not the only option. Nearly three million tons of ash, or more than one-third of all residues, are being reused annually as landfill roadbed materials, daily and final landfill cover, road aggregate, asphalt-mixture, and even cement blocks.
http://www.wtienergy.com/environment1/regulation/index.html |
楼主: 小小辣椒
发表于 2015-7-12 06:38:55
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