Savannah River Site uses passive system to remove groundwater contaminants

June 8, 2022, 3:00PMNuclear News
SRNS environmental engineers Bryce Garner (left) and Adam Willey (center) ask questions of lead operator Daniel Ferrell (right), from field services contractor Cascade Environmental, as he describes how equipment injects oil and iron into the Savannah River Site’s groundwater. (Photo: DOE)

In this week’s “EM Update,” the Department of Energy’s Office of Environmental Management (EM) reports that its contractor Savannah River Nuclear Solutions (SRNS) has successfully reduced degreasing solvents in the aquifer beneath the Savannah River Site in South Carolina using a technology that injects a form of iron and oil into groundwater.

“The oil attracts the Cold War[–era] cleaning solvents while the iron degrades and neutralizes the contamination,” said Shannan Lucero, SRNS manager for area closure projects.

Background: During the nuclear arms race with the Soviet Union, tons of grease-cleaning solvents were released from production buildings in the site’s M Area into clay-bottomed holding ponds, known as basins. Although it was the best technology at the time for storing this type of waste, the solvents began to slowly—over decades—leach into the groundwater, forming a plume beneath SRS.

According to EM, the use of innovative technology to close the basins and eliminate the chemical solvents beneath the open fields where the production facilities once stood has led to exceptional cleanup success.

“Though half of the chemicals have already been safely and harmlessly removed, we will continue to effectively operate cleanup equipment impacting the two primary areas where these solvents have pooled within the plume,” said SRNS environmental engineer Branden Kramer. “We know the solvents will naturally move from the water into the oil, allowing the iron to finish the job. It’s kind of like feeding your pet a pill wrapped in cheese.”

Green technology: SRNS purchased tons of commercially manufactured micron-sized iron bits encased in tiny globules of oil. Employees injected that mixture into the ground at the most needed locations. Studies have shown the iron neutralizes about 90 percent of the affected solvent.

“It’s amazingly effective in its simplicity. We’re really excited about the potential this cleanup technology presents for us and other DOE sites,” said Kramer.

“Environmental cleanup at SRS is often like a series of ongoing, often overlapping battles with different types of waste,” said Lucero. “Some of the waste above ground and some below, some chemical and some radioactive. We’re attacking it with cost-effective, innovative, and frequently low-energy, sustainable green technology. We’re confident this will lead us to achieving our long-term cleanup goals for the site.”

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