Coal Ash Rule Forthcoming
Four years after more than 1 billion gallons of coal ash slurry spilled from a storage pond at the Kingston Power Plant in eastern Tennessee, environmental groups are still waiting for the U.S. Environmental Protection Agency to finalize tougher standards for handling and storing coal ash.
Their wait may soon be over.
Industry observers expect the EPA to issue a rule this year, expanding the oversight of bottom ash management and disposal at U.S. power plants.
The proposed rules would require coal-fired power plants to eliminate wet ash handling and phase out surface impoundments, or ponds, within five years. Anticipating tougher standards, most power producers have already studied the cost of converting to dry bottom ash systems and are bracing for the regulatory changes. The cost of compliance could exceed $20 billion industrywide, according to a 2010 EPA study.
“The overwhelming majority of utilities have done some level of technology investigation and definitely a budget study,” said Kevin McDonough, director of sales Americas for United Conveyor Corp. “Almost all of them have gone that far, so that they understand what technical options are out there and, of course, the approximate cost associated with it.”
The potential market for dry bottom ash conversions is significant. Less than 1 percent of the nation’s coal-fired plants are equipped with dry bottom ash systems, said Ron Grabowski, vice president of Business Development at Clyde Bergemann. More than 90 percent of bottom ash systems remain wet.
“You’re going to have to be a zero discharge plant,” Grabowski said. “If you’re using water to move around your bottom ash, you can’t discharge it.”
In 2010, the EPA offered two proposals to regulate the handling and disposal of coal ash. The first option calls for classifying coal ash as a special waste regulated by the Resource Conservation and Recovery Act (RCRA) Subtitle C hazardous waste provisions. Under the second option, coal ash disposal would be regulated under RCRA’s Subtitle D nonhazardous waste provisions.
In either case, wet ash handling would be eliminated and surface impoundments would be phased out within five years.
“We don’t think they’re going to reclassify bottom ash to be a hazardous material,” Grabowski said. “I think they recognize there are beneficial uses as a byproduct. They want to persuade plants to eliminate the discharge of water.”
In December 2008, a 40-acre coal ash storage pond at Tennessee Valley Authority’s Kingston plant in Harriman, Tenn., failed. The earthen wall collapsed, spilling more than 1 billion gallons of coal ash slurry, damaging 40 homes and contaminating the Emory and Clinch Rivers. The cleanup costs for TVA: About $1 billion.
The incident prompted the EPA to pursue a new rulemaking, but the agency delayed issuing a final rule after intense political pressure from utilities, coal-mining companies and coal ash recyclers who fear classifying coal ash as a hazardous waste would stigmatize their products.
Meanwhile, Congress has proposed legislation that would pre-empt EPA’s proposed rules by granting states the authority to regulate coal ash disposal through the use of permitting programs. Critics say the legislation would keep states in control and stymie the EPA’s effort to promulgate new rules for the disposal of coal ash, also known as coal combustion residuals (CCR).
According to a report by the non-partisan Congressional Research Service, the legislation provides states too much discretion in adopting a permit program or applying federal standards for disposal of coal ash.
“EPA would have no authority to compel states to adopt and implement the program according to provisions in the proposed amendments to RCRA,” the report found.
Coal-fired power plants have three options for the disposal of coal ash. Dry ash can be disposed in landfills. According to the EPA, more than 30 percent of coal combustion waste from power plants is disposed in dry landfills. Coal ash is, of course, stored in ponds, which account for 20 percent of coal ash disposal. About 40 percent of coal ash is recycled and used in a wide range of industrial applications.
More than 300 coal-fired plants in the U.S. dispose coal ash in on-site landfills, according to an EPA report. Nearly 150 plants use off-site commercial landfills for coal ash disposal. Nearly 160 U.S. plants use coal ash ponds for disposal.
The size of coal ash disposal units can range from modest to very large, with some ponds covering 1,500 acres or more.
Meanwhile, power producers using ponds to store coal ash have important choices to make. They have several options and solutions to choose from as they prepare to comply with stricter federal regulation. Those options include submerged flight conveyor (SFC) systems, continuous dewatering and recirculation systems (CDR), pneumatic conveying (PAX) systems, and vibrating ash conveying (VAX) systems.
To learn more about dry ash handling options available to power producers, be sure to read the February issue of Power Engineering magazine.