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Coal-fired power plants generate about 131 million tons of coal combustion residuals-including 71 million tons of fly ash, 20 million tons of bottom ash and boiler slag, and 40 million tons of flue gas desulfurization (FGD) material. Of these Coal Combustion Byproducts [CCBs] 36% are disposed of in landfills, 21% are disposed of in surface impoundments, 38% are beneficially reused, and 5% are used as minefill. Recent upsets from surface impoundments and landfills have created a public media furor - focusing elected and appointed officials to demand more stringent regulatory control.

Preface

During the past several months, following the TVA ash and scrubber sludge spill in Kingston, Tennessee, the public and media have elevated this incident - engaging elected officials and federal/state regulators. This spill occurred on December 22, 2008, when an ash dike ruptured at an 84-acre (0.34 km2) coal waste containment area at the Tennessee Valley Authority's Kingston Fossil Plant in Roane County, Tennessee, USA. 1.1 billion gallons (4.2 million m3) of coal fly ash slurry was released.

The coal-fired power plant, located across the Clinch River from the city of Kingston, uses ponds to dewater the fly ash, a byproduct of coal combustion, which is then stored in wet form in dredge cells. The slurry (a mixture of fly ash and water) traveled across the Emory River and its Swan Pond embayment, on to the opposite shore, covering up to 300 acres (1.2 km2) of the surrounding land, damaging homes and flowing up and down stream in nearby waterways such as the Emory River and Clinch River (tributaries of the Tennessee River). It was the largest fly ash release in United States history.

In May 2009, the U.S. Environmental Protection Agency (EPA) signed an enforceable agreement with the Tennessee Valley Authority (TVA) to oversee the removal of coal ash at the TVA Kingston Fossil Fuel Plant in Roane County, Tenn., where more than 5 million cubic yards of coal ash spilled last December.

The cost of this clean-up is estimated at almost one billion dollars; TVA's predicted estimate ranges from $675 million to $975 million. For example, a Middle Georgia landfill is accepting test loads of coal ash waste this week from this historic Tennessee spill. The Veolia landfill in the Taylor County town of Mauk is vying to receive the roughly 5.4 million cubic yards of waste from the spill.

Current Methods of Handling Coal Combustion Byproducts

• Bottom Ash and Slag

Bottom ash collection systems often consist of water-filled tanks or hoppers located under the boiler. They vary in size, shape and other design aspects. Water in the hopper quenches the ash and causes it to fracture into smaller sizes. It is also necessary to cushion the fall of material and protect the refractory walls of the vessel. Water is also utilized as an agent to wash or "sluice" ash out of the hopper for disposal.

• Fly Ash and FGD Sludge - Landfill

Typically, fly ash is collected in the electrostatic precipitator or baghouse hoppers and conveyed by blowers to silos for temporary storage. From the silos, fly ash is discharged into pug mills where it is mixed with scrubber sludge for disposal in the on-site landfill. The silos can also be discharged dry into trucks for off-site use.

• Fly Ash and FGD Sludge - Ponding

Pond containment dike slope stability depends on construction materials as well as subsurface soil conditions below the embankments and ponds. These ash landfills/ponds need to be designed to prevent localized slope failures that weaken the embankment or global failure that causes the entire embankment to rupture.

Slopes cannot be too steep. Typically slopes greater than two horizontal (H) to one vertical (V) are prone to erosion, slip failures, and global stability failures. Soil types, strength of the soils utilized for construction of these slopes, and groundwater conditions all impact slope stability.

At the Kingston site, TVA employed wet ponding rather than dry landfill. The TVA Kingston Fossil Plant coal fly ash slurry spill occurred, when an ash dike ruptured at an 84-acre (0.34 km2) solid waste containment area releasing the coal fly ash slurry. According to the 1 5 09 Tennessean, a dry collection system - a method that is more labor intensive - is considered more environmentally safe for waterways and groundwater than the wet method. It also was the most expensive fix at $25 million, according to TVA. The liner installation was estimated at $5 million, but TVA noted that it would set "a precedence for all other dredge cells" and "take a long time to construct."

The cheapest option, a new dredge cell, would cost $480,000 and was a possibility for the short term, according to TVA in 2003, but could be viewed as a lateral expansion that would require the onus of a major permit modification, the update said.

In April 2005, TVA submitted a proposal for repair that would include a series of trench drains at different levels on the dike, another drain at the base of the mound and a riprap channel. Trench drains were not mentioned in the earlier 2003 options.

"Effectiveness, constructability, economics and practical experience led TVA to focus its efforts on trench drains as the preferred fix," the April 2005 TVA report said. TVA urged quick approval of its plans so it could make repairs and resume dredging. During Jan. 2009 Public Works Hearings, Tom Kilgore [TVA CEO] said that TVA had chosen to implement inexpensive patches instead of more extensive repairs of the holding ponds, admitting, "Obviously, that doesn't look good for us."

TVA is not alone in opting for less costly and traditional retrofit to CCBs ponding in unlined retention basins. Wet ponding of CCBs represented typical practice in the 1950's when Kingston was constructed. Dry landfill of CCBs also reflect upsets - resulting in expensive legal and regulatory settlements.

For example, on Oct. 1, 2007 the Maryland Department of the Environment (MDE) signed a consent decree requiring Constellation Power Source Generation Inc. and BBSS Inc. to pay a $1 million penalty and clean up contamination from fly ash disposal. Constellation Energy, the Murphy Firm and the Law Offices of Peter Angelos announced that the parties have reached a settlement agreement regarding a class action lawsuit filed by residents in Gambrills, Md. who alleged they were damaged by the use of coal ash to reclaim a sand and gravel quarry in Anne Arundel County. The settlement is subject to approval by the Circuit Court for Baltimore City. The settlement provides for: (1) the connection of 84 households, previously supplied by private wells, to public water; (2) the establishment of two trust funds to compensate affected property owners and provide site enhancements in the neighborhood; (3) the remediation and restoration of the former quarry site; and (4) the commitment to cease future deliveries of new coal ash to the quarry. The costs and benefits of these expenditures and improvements currently are estimated to be $45 million.

Media and Public Furor

These incidents have contributed to a public media furor regarding management of CCBs

The New YorkTimes(1) states "1,300 similar dumps across the United States - most of them unregulated and unmonitored - that contain billions more gallons of fly ash and other byproducts of burning coal." Further regulation is advocated. "The lack of uniform regulation stems from the E.P.A.'s inaction on the issue, which it has been studying for 28 years. In 2000, the agency came close to designating coal ash a hazardous waste, but backpedaled in the face of an industry campaign that argued that tighter controls would cost it $5 billion a year. (In 2007, the Department of Energy estimated that it would cost $11 billion a year.) At the time, the E.P.A. said it would issue national regulations governing the disposal of coal ash as a nonhazardous waste, but it has not done so."

Similar demands are echoed by environmental advocacy groups - influencing elected officials to pressure regulatory to create more stringent requirements for CCB disposal practice.

Implications - More Stringent Regulatory Control

• Federal Regulations History

In 1980, the U.S. Congress adopted the Bevill Amendment, an amendment to the Resource Conservation & Recovery Act (RCRA). The U.S. Environmental Protection Agency (EPA) was required to conduct a detailed study on the adverse effects of the disposal and utilization of fly ash, bottom ash, boiler slag, and other byproduct materials produced from the combustion of coal.

On August 2, 1993, EPA presented its final regulatory decision on fly ash, bottom ash, boiler slag, and flue gas emission control waste, stating that these materials are not regulated as hazardous wastes under Subtitle C, and officially placed them under Subtitle D as solid wastes under the jurisdiction of individual states. EPA was to further evaluate the hazardous or toxic properties of industrial solid wastes, but at this time, coal combustion byproducts (CCBs) were expected to remain under state regulation.

EPA preliminarily concluded in March 1999 that the remaining wastes not covered under RCRA Section C also did not warrant federal hazardous waste regulation. Environmental groups attacked this preliminary conclusion, citing public health concerns, hazardous environmental effects, and poor state regulation enforcement. A final decision was delayed several times, and at the beginning of 2000, EPA appeared ready to push for a hazardous designation. However, in April 2000, EPA determined reuse of CCBs did not warrant regulatory oversight. This landmark decision cleared the way for continued progress in the beneficial reuse of CCBs.

In May 2009, the U.S. Environmental Protection Agency (EPA) committed to issuing proposed regulations for the management of coal combustion waste by utilities by the year's end, a senior agency official told the House Transportation and Infrastructure committee. Rules could include tightened restrictions on contaminants in wet scrubber wastewater streams. Barry Breen, acting assistant administrator for the EPA's Office of Solid Waste and Emergency Response, said that as a result of the massive coal ash spill at the Tennessee Valley Authority's Kingston plant in December 2008, the agency had embarked on a "major effort to assess the stability" of similar impoundments and other management units containing wet-handled coal combustion waste.

"This assessment has three phases: information gathering through an information request letter; site visits or independent assessments of other state or federal regulatory agency inspection reports; and final reports and appropriate follow up," he said in testimony before the Subcommittee on Water Resources and the Environment on Thursday. "Currently, we are still in the information gathering phase and plan to begin field work in May of this year".

The purpose of the hearing was to gather more information about the disposal of coal combustion waste and water quality. USEPA Administrator Lisa Jackson promised, during her confirmation hearing, to promulgate stricter coal plant waste storage regulations (2) Capitalizing on the political opportunity of the TVA Kinston Spill will escalate with continued congressional hearings. Elected and appointed officials will find the coal industry an easy and demonized target to impose more stringent regulations (3).

Discussion

The incidents and consequences should not indict coal-fired power plants nor the electric utility industry; unexpected costs from ten to hundreds of million dollars and public embarrassment are sufficient punishments. How to avoid such upsets should be the focus of Coal Fired Power Plant operators and the Electric Utility Industry.

An Engineering Approach, reflecting demonstrated technology and recognizing CCBs chemical and geotechnical properties, should be embraced by the Electric Utilities with coal-fired power plants. Commitments - to regulators - to develop and implement this approach should curb excessive requirements. Electric utilities should capitalize upon the industry-wide knowledge and submit to USEPA as regulatory approaches are being developed.

References - Specific Citations
(1) S. Dewan; "Hundreds of Coal Ash Dumps Lack Regulation"; The New York Times; January 7, 2009

(2) R. Andracsek; "The Obama EPA: A First Look"; Power Engineering Vol 113, No. 4, April 2009, p. 10

(3) [A.. Neville, "Politics Surrounding Coal Ash Management"; POWER; Vol 153, No. 5, May 2009; pgs 22 - 24.]

References - General
http://en.wikipedia.org/wiki/Fly_ash

We Energies Coal Combustion Products Utilization Handbook
www.we energies.com/environmental/ccp_handbook_ch2.pdf