Page 3 - SRNS Today November 2021

NOVEMBER 2021 | SRNS TODAY | 3

Site employees test materials

to immobilize iodine-129

in groundwater

Two Savannah River Ecology Laboratory soil
scientists, Jeffrey Lott and Christina Logan,
monitor experimental test equipment used to
remove Iodine-129 from groundwater at SRS.

or 33 years, during the U.S.-Soviet Cold War, wastewater
was released to pond-like basins near two nuclear fuel
processing facilities at SRS. Over the decades, wastewater “The wastewater was responsibly treated using the best
that contained trace amounts of radioactive iodine-129 slowly available technology at the time. That said, we’ve come
migrated down through the soil and into the water table. a long way since this all began in the 1950s.”
“The wastewater was responsibly treated using the best available Jeff Thibault
technology at the time. That said, we’ve come a long way since this
all began in the 1950s,” said Jeff Thibault, SRNS engineer. “The
cleanup technology currently used binds the iodine radionuclides
to earthen sediment within the aquifer, effectively locking them into
place. Unfortunately, that same technology can’t be used to treat iodine-129 underground before rising to the surface in the marsh.
the leading edge of the plume, which has reached a large marshy “We want to create a solid treatment barrier that will allow the
area at SRS. This presents a new cleanup challenge for us as the groundwater to pass through, but not the iodine-129,” he said.
contamination surfaces in the marshlands.”
The first phase of this project involves extensive laboratory testing of 11
According to Thibault, off-the-shelf, ready to be purchased promising materials by John Seaman, Ph.D., SREL Research Professor.
groundwater treatment for this type of cleanup environment does not
exist. “We’ve become adept at developing highly effective remediation SREL scientists in the field and SRNS engineers are currently testing
techniques for a variety of contaminants at SRS, both chemical and four of the 11 materials using contaminated water from the aquifer. The
radioactive techniques that many sites across the DOE complex materials are zero-valent iron, porous iron composite, granular activated
have adopted. We have some of the most creative and innovative carbon and a mixture of iron and carbon.
engineers and scientists in the world tackling these issues. And we’re “We hope to get positive results out of this first phase of testing. We
asking them to apply their expertise and knowledge to this new task, also have funding in our budget for next year to test other sorbents or
working with the University of Georgia’s Savannah River Ecology other combinations of sorbents,” said Thibault. “I’m very interested in
Laboratory (SREL) to make it a reality.” the mixing of materials. Zero-valent iron may be good. But zero-valent
Thibault stated that the ultimate goal is to identify a material that iron with carbon may be fantastic.”
can be placed underground at the edge of the marsh, creating a SRS is the recognized leader throughout DOE, related to iodine-129
permeable barrier. Upon contact, this material would immobilize the environmental remediation.