IDAHO FALLS, Idaho – Workers at the Idaho site have enlisted microbes to help remediate previously contaminated groundwater and advance the protection of the Snake River Plain Aquifer.
The microbes in the aquifer are fed a mixture of sodium lactate and whey powder, a common ingredient found in sport protein drinks.
“The microbes eat it, and in the process break down trichloroethylene (TCE). Although TCE is a carcinogen, the end products are harmless,” said Lorie Cahn, environmental lead for Environmental Restoration (ER) and Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) at CH2M-WG Idaho (CWI), the Idaho site’s main cleanup contractor.
From 1953 to 1972, large volumes of industrial solvents and other waste were pumped directly into the aquifer and a mile-and-a-half plume of groundwater extending southeast from an old injection well. TCE was used to remove grease from the nuclear-powered jet engine. Three portions of the plume are being remediated.
Sodium lactate injections began in 1999 and whey protein was added in 2005. In order for the bioremediation process to be as efficient as possible, pH levels have to be carefully controlled. Whey is added to control pH levels and sodium lactate is added to act as a buffer, minimizing drops in pH levels. The microbes are proving to be successful.
“When the wells were first sampled in the mid-1990s, the TCE levels were about 20,000 parts per billion. Some are now almost non-detectable,” said Evan Myler, operations supervisor for CWI’s ER/CERCLA project.
The old injection well is located at Test Area North (TAN), which once supported numerous research efforts for advancement of the country’s nuclear industry. Those efforts included the development of nuclear-powered jet engines and operation of the Loss of Fluid Test (LOFT) reactor, which simulated the loss of coolant to allow engineers, scientists and operators to create or recreate and study loss-of-fluid accidents, or reactor meltdowns, under controlled conditions.