The underlying Snake River Plain Aquifer is considerably safer today following three decades of EM cleanup activities at DOE’s Idaho National Laboratory Site.
The underlying Snake River Plain Aquifer is considerably safer today following three decades of EM cleanup activities at DOE’s Idaho National Laboratory Site.

IDAHO FALLS, Idaho – The environment at DOE’s Idaho National Laboratory (INL) Site and underlying Snake River Plain Aquifer are considerably safer today following 30 years of cleanup in compliance with state and federal regulations.

When the DOE, state of Idaho, and U.S. Environmental Protection Agency signed the Federal Facility Agreement and Consent Order (FFA/CO) in December 1991, they outlined a plan to investigate and clean up, if necessary, more than 500 individual waste areas within the 890-square-mile site, which was established in 1949 to design, build, and test nuclear reactors for land, sea, and air applications.

Waste sites, consisting of unlined wastewater disposal ponds, debris piles, radioactive groundwater plumes, buried barrels and boxes of radioactive and hazardous wastes, and even unexploded ordnance, have since all been evaluated and most of the cleanup is complete.

“This agreement has stood the test of time,” said Connie Flohr, EM manager for the Idaho Cleanup Project. “It provides the regulatory framework that we still use today to complete our cleanup work.”

Crews will finish a project about 18 months ahead of schedule that has removed more than 10,250 cubic meters, or more than 49,000 drums, of radioactive and hazardous waste from an unlined Cold War landfill known as the Subsurface Disposal Area.

Three vacuum-extraction units that removed more than 258,000 pounds of solvent vapors from beneath the landfill and destroyed them with catalytic oxidation technology were turned off in August 2020 to determine if vapor concentrations would meet remediation goals under natural conditions. Sampling and analysis of thousands of vapor samples has shown that performance goals and remedy objectives were achieved early.

Both of those projects — removing waste from the landfill and use of the vacuum-extraction units — were designed to protect the aquifer, which lies 585 feet below the landfill surface.

Following cleanup, the construction of earthen covers, and plant reseeding, many areas at the 890-square-mile Idaho National Laboratory Site will resemble the native desert on the Eastern Snake River Plain.
Following cleanup, the construction of earthen covers, and plant reseeding, many areas at the 890-square-mile Idaho National Laboratory Site will resemble the native desert on the Eastern Snake River Plain.

At the north end of the site, more than 825 million gallons of water have been treated with a pump-and-treat system during the last 20 years. Additionally, bioremediation is in progress and consists of injecting sodium lactate or a similar product into a contaminant plume in the aquifer to create conditions favorable for naturally occurring microorganisms to “feed” on the waste. An additional well was completed this summer to help target a residual trichloroethylene source zone in the aquifer that was inaccessible using existing wells.

“The amount of environmental cleanup work that crews have completed is impressive,” said Fred Hughes, program manager for EM INL Site contractor Fluor Idaho. “The progress is visible, and the aquifer is benefitting from a host of waste remediation projects.”

Construction of the 510,000-cubic-yard Idaho Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) Disposal Facility in the early 2000s has allowed DOE to consolidate waste material from many areas of the site into a single, managed landfill that includes several feet of impermeable liners as well as a leachate collection system and lined disposal ponds.

In coming weeks, crews are scheduled to complete targeted buried waste exhumation of the 5.69 acres of the landfill that posed the greatest risk to people and the environment. This completion, coupled with the successful vacuum extraction of solvent vapors from it, protects Idaho residents, wildlife, and the environment by safeguarding the Snake River Plain Aquifer. The commitment to protect people and the environment continues to be the paramount focus of the agreement between the Idaho Department of Environmental Quality, EPA, and DOE.

These successful environmental remediations have occurred in parallel with efforts to treat radioactive liquid wastes from a tank farm at the INL Site and ship stored waste out of the state for permanent disposal.

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