The Tennessean reported that Tennessee Valley Authority plans to quit storing ash from its coal-fired power plants in wet landfills, like the one that devastated an East Tennessee community when it broke eight months ago, an official said Monday. The overhaul of ash ponds is expected to take eight years.
The planning is in advance of draft U.S. Environmental Protection Agency regulations on coal ash that federal officials say will be released in December. The new rules are driven largely by the TVA spill on top of a few elsewhere in previous years. Dry storage has been the growing preferred method of ash handling in the industry, which for years worked to forestall regulation of ash.
The costs of the changeover will exceed $25 million, says John Kammeyer, vice president of coal combustion products.
TVA’s gypsum ponds will also be converted.
Barbara Martocci, a TVA spokeswoman, said she did not know whether the change would trigger a rate increase.
“The trend in the industry is to go to dry storage,” said Thomas Adams, executive director of the association office in Aurora, Co. “It’s much more reusable if you want to go pull some of that ash out.”
The powdery fly ash is still slightly damp, but not soaked as it is in the wet system, which uses water to sluice ash to holding ponds.
About 43 percent of the ash from coal plants around the country is recycled as an additive in materials that include asphalt and concrete blocks, according to the association. ACerS has published several papers regarding positive results with using fly ash and other waste products as a substute for Portland cement. For example, ACerS International Journal of Applied Ceramic Technology published a paper [subscription required] by a University of Texas research team that showed that Portland cement can be successfully synthesized by replacing reagent-grade chemicals with up to 40% fly ash and 60% steel slag incorporation.
TVA burns about 45 million tons of coal a year, resulting in about 4.5 million tons of ash. Up to 40 percent of the ash has been marketed, Martocci said.
The dry process, more costly than the wet, has benefits in addition to leaving the powdery fly ash more available for reuse. These include saving water and reducing the chances of ash sludge slides.