Using funding provided under the American Reinvestment and Recovery Act, the U.S. Department of Energy's Savannah River National Laboratory (SRNL) has launched a demonstration project near one of the Savannah River Site's (SRS) former production reactor sites to clean up chemically contaminated ground water, naturally.
of the subsurface at the Site's P Area has become contaminated with chlorinated
volatile organic compounds that are essentially like dry-cleaning fluid. SRNL
and Clemson University have patented a consortium of
microbes that have an appetite for that kind of material.
they are as effective as we expect in cleaning up the chemical contamination in
the ground water, it will be far cheaper than energy-intensive types of
cleanup, such as pump-and-treat techniques or soil heating," says Mark
Amidon, SRNL's project manager for the demonstration.
of microbes was found occurring naturally at SRS, where they were feeding on
the same kind of chemical that was in ground water seeping into an SRS creek.
SRNL and Clemson University worked together on the
discovery and characterization of the microbes. The mixture is called MicroCED,
for "microbiological-based chlorinated ethene destruction," and when
injected into the subsurface can completely transform lethal chlorinated
ethenes to safe, nontoxic end products.
In P Area,
the first step was to make ground water conditions better for the microbes.
"In late summer, we injected more than 5,000 gallons of emulsified soybean
oil, buffering agents and amendments and 108,000 gallons of water to get the
dissolved oxygen and acidity right," Amidon notes. "Once the
conditions were right, we started injecting the store of microbes we've been
culturing." An initial application of 18 gallons of the microbes recently was
injected to get things started. By the end of the demonstration, approximately
1,500 gallons of the microbes could be injected into the demonstration site.
estimates that it would take a year or more to see appreciable results.
"You can't rush Mother Nature." The current test site is about 100
feet by 120 feet at the surface and 85 feet to 100 feet below ground, and will
be used to determine whether this approach should be used for full-scale
treatment of the area. "If we were to go full-scale, there would be a
'biowall' about 1,000 feet long and between 50 and 145 feet below ground,"
has been working in bioremediation for many years, using existing
microorganisms as part of the strategy. The difference here is the culturing
and injection of quantities of a specific mixture of microbes for use on
Low-energy Ground Water Remediation with Microbes
February 10, 2011