The cleanup began the day after the ash spill as workers began building a rock berm wall in the river to make sure that none of the ash migrated downstream.

TVA, with EPA and the Tennessee Dept. of Environment and Conservation, devised a two-part cleanup plan: Ash from the river would be removed first, as “time critical” and ash outside of the river “non-time- critical” would come later.

Five dredges operated by Niagara Falls, N.Y.-based Sevenson Environmental Services worked 24-hour days to remove the ash from the river. A total of 3.5 million cu yd was removed from the river, dewatered and then loaded onto rail cars. From there, it was sent to an EPA-approved landfill in Perry County, Ala. More than 40,000 individual rail cars, carrying 4 million tons of ash, made the trip. That work was completed in May 2010, when TVA began focusing on the non-time critical ash removal.

That work is ongoing and challenging. Amphibious backhoes and front-end loaders have to remove the ash from what had been a pond while keeping the ash from getting too wet and then liquified. In order to keep spring-fed water from moving ash off-site, TVA built a dike to keep the water in an area cleaned of ash.

The dike is one of the TVA's changes that make this job different from other multiyear environmental cleanups, says Steve McCracken, general manager of the TVA's Kingston Ash Recovery Project. McCracken joined TVA in 2009 after a career with the U.S. Dept. of Energy as a manager of DOE cleanups.

Re-examining Storage

Coal-ash ponds have long been ignored by most utilities, Kammeyer says. They were often built as after-thoughts and below today's standards. However, until Kingston, there had been no major outages or problems caused by the coal-ash ponds.

After Kingston, though, TVA and EPA realized more attention had to be paid to the disposal facilities and how they are managed. Edmonton, Alberta-based Stantec Inc. was hired to analyze the stability of the existing disposal facilities at all 11 of TVA's coal-fired plants. At the same time, Los Angeles-based AECOM was brought in to conduct a root-cause analysis of the problems at Kingston. AECOM determined that four factors—a slime-like layer of soil; a high ash pile; wet, loose ash; and the dike's angle and setbacks—caused the dike failure.

Stantec found problems at the other 10 facilities, says John Montgomery, senior principal for Stantec on the TVA job, though none rivaled the combination of problems that led to the ash spill at Kingston,

Along with San Francisco-based URS Corp., Stantec engineered the solutions, and TVA has completed or will complete by year's end more than 86 capital projects totaling more than $100 million.