STEWART HOUSTON TIMES

TVA plans coal ash safety upgrades at Cumberland Fossil Plant

Mark Hicks
Clarksville Leaf-Chronicle

TVA has come up with new ways to safely manage the way coal ash is stored at the Cumberland Fossil Plant. And not only will the project improve safety, TVA says it will also inject millions of dollars into local economies.

TVA is seeking public input on options they have developed for dry storage of all residue from the coal-burning process.

TVA is drafting an Environmental Impact Statement on its handling of coal combustion residuals, or CCRs, at the plant.

In the wake of a massive 2008 spill of coal ash sludge at TVA’s coal-fired plant in Kingston that flooded more than 300 acres and released coal ash into nearby rivers, the Environmental Protection Agency passed regulations in 2015 for coal ash disposal.

TVA also decided to move to dry storage of CCRs, which contain pollutants like arsenic and boron, at all of its coal-fired power plants. At the Cumberland plant, most of CCRs were already being stored dry in lined landfills on site.

While not all of EPA’s guidelines are finalized, TVA is getting ahead of the process, moving forward with projects at the Cumberland plant and others to transition to dry storage and to meet future regulations.

Bottom ash from the power plant's coal furnace is collected in a pond before it proceeds to another larger pond where the solids settle to the bottom and later dredged out to dry.

How ash is created, stored

Burning coal at the power plant produces three byproducts: gypsum, fly ash and bottom ash.

Currently, TVA “dry stacks” gypsum and fly ash at Cumberland, which means the water is removed and the material is compacted. Some of the gypsum is sold to the adjacent Georgia-Pacific wallboard plant, and the fly ash is sold as a hardening additive for concrete.

The bottom ash, a molten material that collects at the bottom of the six-story blast furnace, is ground up and transported with water to holding ponds, where it settles to the bottom. Eventually, it is dredged out and allowed to dry before being added to the fly ash dry stack.

Water from the pond then moves to another retention pond, where it stays until it meets state and federal water standards. It is then returned to the Cumberland River.

Better solutions

TVA’s proposed solution for bottom ash is to build a “de-watering” facility to remove the water and either build an 80-acre landfill on-site to store it in a dry stack or to truck the dry bottom ash somewhere else for disposal.

Another option to consider is how to deal with the holding ponds currently used to store the bottom ash. Should those ponds, or impoundments, be closed “in-place” or should the contents be removed from the site?

Bottom ash and other water used in processes at the Cumberland power plant are stored in a large pond on site. The ash and other solids are removed, dried and added to a landfill of other ash. TVA is looking to do away with such wet storage at Cumberland, as well as other coal-fired power plants across the system.

Darrell Tipton, the project manager, said another question is raised if the decision is made to transport the CCRs from the site to an approved landfill elsewhere.

“Either way, you are going to put trucks on the road,” he said. “So you’re traveling though towns with ash in the back of trucks.”

Michelle Cagley, TVA’s manager for environmental support, added, “In other communities, people are opposed to truck traffic.”

Project Manager Darrell Tipton explains how TVA plans to change the way residue from the coal-burning process is stored at the Cumberland Fossil Plant in Cumberland City. A red-shaded area at the lower left of the map is a proposed 80-acre landfill for coal ash.

The project would cost $100 million to $200 million and would likely take years to complete.

“To do this work, that money goes somewhere – labor, materials,” Tipton said. “A lot of folks are going to be busy for a while doing this. So it’s an injection into the local economy just to build this stuff.”

He said such a large-scale project is an investment by TVA in the Cumberland Fossil Plant, which is the largest in the federal utility’s fleet. 

“This is an investment in the future of the plant long-term,” added TVA spokesman Scott Brooks.

Collecting opinions

TVA is seeking public comment on the proposals at an open house from 4 to 6:30 p.m. on Nov. 28 at the Cumberland City Fire Hall, 402 Thomas Ave. in Cumberland City.

“If something comes to light that we weren’t aware of, or if we see a lot of public opinion one way or another, then that gets factored into the decision that’s made,” Cagley said. “We do look at the feedback we get and consider it as TVA makes their decision on this.”

Written comments can be emailed to aemasters@tva.gov or mailed to Anita E. Masters, NEPA Project Manager, Tennessee Valley Authority, 1101 Market St., BR 4A, Chattanooga, TN 37402.

The public comment period on the Environmental Impact Study opens on Friday and continues through Jan. 2.

Mark Hicks can be reached at 931-212-7626 or on Twitter: @markhicksleaf.