Groundwater contamination at the site of old Oak Ridge Gaseous Diffusion Plant in Tennessee may persist beyond 2020, when the Department of Energy’s current $2.5 billion cleanup contract with URS-CH2M Oak Ridge (UCOR) ends.
David Adler, director of DOE’s Oak Ridge Environmental Management Quality and Mission Support Division, told a local advisory board that some groundwater plumes on the site are still contaminated with industrial solvents such as trichloroethylene.
He said the solvents were common on industrial sites and were isolated in areas where disposal activities occurred.
“We have hundreds of wells on the site and have a very sound understanding of groundwater conditions at the site and are able to say which areas appear to have no problems at all, and also that some areas have been degraded,” Adler said.
Oak Ridge Environmental Management Office spokesman Ben Williams said DOE has found no evidence that the contaminated water has migrated off-site from the former uranium enrichment site. Most of the plumes are located toward the interior of the property, near the plot of land that was once the K-25 Gaseous Diffusion Processing Building.
The groundwater remediation is important because the 2,200 acres of land under the Cold War-era site is scheduled to be turned over for reuse after UCOR finishes its contract in 2020. The Energy Department to date has transferred about half of the property out of its liability, but will remain responsible for restoring the water after the contract ends, Adler said.
“Our goal is to leave that site with minimal site use restrictions,” he said. “That means removing buildings that have exceeded [their] useful life, removing contaminated soils that are incompatible with reuse, and to the maximum extent practicable, restoring the groundwater.”
Environmental Management is considering treatability studies to identify groundwater restoration options. Adler said one of those involves heating the subsurface around the groundwater plumes to drive off contaminants and collect them at the surface.
The main issues, Adler said, are the complex geology at the site and the cost-effectiveness of whatever treatment options DOE identifies.
“The objective is to restore groundwater to its highest potential use,” he said. “However, in some cases, that is technically impractical. This may be one of those cases.”
Adler said the information the office obtains from a treatability study can help Environmental Management evaluate treatment applications at other areas in Oak Ridge as well.
