News Feature | June 10, 2016

Sludge Removal Reduces Radioactivity At Tennessee Waste Plant

Sara Jerome

By Sara Jerome,


Radioactivity levels have dropped at a Tennessee sewage plant after years spent trying to clean up the problem.

A U.S. Department of Energy contractor tasked with the cleanup said radioactivity is down by 90 percent over two years, according to the Knoxville News Sentinel.

Project spokeswoman Anne Smith “said the contractor recently completed its 18th shipment of radioactive sludge to an [out of state] facility,” the Associated Press reported.

The radioactive sludge heads to a plant in Richland, WA. Leftover material gets treated thermally and goes to a Utah landfill.

“Levels of technetium-99 in the sewage plant's ‘sludge digester’ have dropped from 904,000 picocuries per liter in April 2014 to 91,100 picocuries per liter in March 2016. A picocurie is one-trillionth of a curie, a standard measure of the intensity of radioactivity in a sample of radioactive material,” the Knoxville News Sentinel reported, citing Smith.

“Sludge has been removed periodically from the Rarity Ridge Wastewater Treatment Plant to help reduce the levels of radioactive technetium-99, which infiltrated pipelines leading to the sewage plant during demolition activities at the former K-25 uranium-enrichment facility,” the report said.

The Oak Ridge sewage plant became aware of its radioactive sewage problem two years ago.

“The unwelcome surprise was blamed on technetium-99 that had migrated from a demolition project at the federal government's K-25 uranium-enrichment plant on the other side of the Clinch River,” the Knoxville News Sentinel previously reported.

Technetium-99 has been linked to cancer in humans, according to the U.S. EPA.

It can “pose a health risk when it enters the body. Once in the human body, Tc-99 concentrates in the thyroid gland and the gastrointestinal tract. The body, however, constantly gets rid of Tc-99 through feces. As with any other radioactive material, there is an increased chance that cancer or other adverse health effects can result from exposure to radiation,” the agency says.

For similar stories visit Water Online’s Sludge And Biosolids Processing Solutions Center.

Image credit: "toxic," Lauri Heikkinen© 2015, used under an Attribution 2.0 Generic license: