Office of Environmental Management

Treatment Systems Protect Nation’s Second-Largest Aquifer at Idaho Site

December 5, 2017

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Sodium lactate, a food additive, is used to stimulate microorganisms in the aquifer.
Sodium lactate, a food additive, is used to stimulate microorganisms in the aquifer.

IDAHO FALLS, Idaho – A pump-and-treat system is set to surpass treatment of 700 million gallons of water within the next few months in one of two cleanup projects removing contaminants from the nation’s second-largest aquifer beneath EM’s Idaho Site.

   The pump-and-treat system near the former Test Area North facility began operating 15 years ago. It removes the industrial solvent trichloroethylene, which was injected into the Snake River Plain Aquifer — along with other liquid wastes — from 1955 to 1972. 

   A carbon source is also injected into the aquifer near the former injection well to stimulate naturally occurring microorganisms in the aquifer to degrade solvents in a process called bioremediation.

The pump-and-treat system at Test Area North has treated nearly 700 million gallons of water.
The pump-and-treat system at Test Area North has treated nearly 700 million gallons of water.

   These groundwater treatment projects will reduce the aquifer’s trichloroethylene concentrations to below drinking water standards in compliance with a record of decision by DOE, the state of Idaho, and U.S. Environmental Protection Agency.

   Test Area North was established in the early 1950s to build and test nuclear-powered jet aircraft engines for an aircraft nuclear propulsion program that ended in 1961. The facility was later used to study the effects of the loss of coolant from commercial reactors.

Vapor vacuum extraction units like this one have removed a quarter million pounds of solvent vapors from the ground beneath the Radioactive Waste Management Complex.
Vapor vacuum extraction units like this one have removed a quarter million pounds of solvent vapors from the ground beneath the Radioactive Waste Management Complex.

   A vapor vacuum extraction technology has captured and destroyed a quarter million pounds of solvent vapors from the ground since it began operating more than 20 years ago. It prevents the vapors from reaching the aquifer beneath the site’s Radioactive Waste Management Complex.

   This technology draws organic vapors from the ground with high-pressure pumps, destroying them at the surface through catalytic oxidation units, in the same way an automobile destroys unburned fuel vapors.

   Thousands of barrels of solidified solvents (also containing radioactive material), remnants of weapons production at the former Rocky Flats Plant, were buried at the complex from 1954 until 1970. As the barrels deteriorated, solvents escaped the waste zone in the form of vapors, driven toward the aquifer by precipitation. 

   Fluor Idaho is removing the deteriorating barrels of radioactive and hazardous waste from the landfill. The Idaho Cleanup Project contractor has about 1 more acre of material to exhume under its contract.