Duke seeks approval of wastewater changes for East Bend coal plant

Duke Energy Kentucky on Dec. 2 requested that the Kentucky Public Service Commission grant a Certificate of Public Convenience and Necessity (CPCN) for it to construct new water redirection and wastewater treatment processes, and to close and repurpose its existing coal ash impoundment so to accommodate these processes at its coal-fired East Bend plant.

Emerging environmental regulations, such as the U.S. Environmental Protection Agency’s recently published Disposal of Coal Combustion Residuals from Electric Utilities rule (CCR Final Rule), and recently published Steam Electric Effluent Limitations Guidelines (ELG Final Rule), directly affect the handling of ash at coal-fired generating stations like East Bend, Duke noted.

  • The ELG Final Rule sets new or additional requirements for wastewater streams from several processes and byproducts at steam electric generating plants, including East Bend. These requirements necessitate the modification of the current pond configuration in order to change the manner in which certain wastewater streams are handled.
  • The CCR Final Rule, among other things, impacts the handling of fly ash, bottom ash, and flue gas desulfurization (FGD) byproducts (typically, calcium sulfate (gypsum) or calcium sulfite) that are destined for disposal (CCRs) through the imposition of additional constraints for continuing the use of coal ash impoundments like the pond at East Bend Pond.

Because of the lead times for equipment fabrication and acquisition and looming compliance deadlines the company requested that the commission consider this application in an expedited manner and issue an order by April 30, 2017. In order to meet the ELG compliance deadlines and to complete construction during already planned maintenance outages, Duke Energy Kentucky needs to commence construction as soon as practical.

East Bend includes a single 600-MW (net) coal-combustion generating unit and is Duke Energy Kentucky’s only baseload and coal-fired resource. Coal combustion byproducts from East Bend are currently disposed of in an on-site landfill owned and maintained by Duke Energy Kentucky (East Landfill). Duke Energy Kentucky is constructing a second, replacement on-site landfill that is referred to as the “West Landfill.” The East Landfill is comprised of approximately 162 acres and has been in place since East Bend was constructed in 1981. The West Landfill, once all phases are completed, will consist of approximately 200 acres of lined landfill that is designed to accept approximately 30 years of generator waste from the East Bend Station and other permitted sources only as necessary to properly formulate fixated material from East Bend’s scrubber sludge for ultimate disposal.

The bottom ash produced at East Bend is currently treated in the onsite pond for eventual landfill disposal in compliance with the company’s National Pollution Discharge Elimination System (NPDES) Permit and the Special Waste Facility Permit from the Kentucky Division of Waste Management. The pond was commissioned in 1981, has a volume of 1,844 acre feet, and is used to separate bottom ash from the water used to convey the ash from the plant before the water is discharged to the Ohio River from the pond under the NPDES Permit. The pond is also used to treat other plant water streams, such as coal pile run-off and landfill leachate, before they are discharged under the NPDES permit. The boiler bottom ash is collected in a wet bottom ash hopper at the base of the boiler and then sluiced to the pond.

Duke Energy Kentucky recently applied for a CPCN to convert East Bend’s wet bottom ash handling system to a dry ash handling system in compliance with the ELG and CCR Final Rules. The conversion to the dry-ash handling system, as well as the new process water requirements, are necessary improvements for compliance with the ELG Final Rule, which in turn, makes the continued operation of the pond in its current form both incompatible and unnecessary.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.