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CHEYENNE, Wyo. — After eight years of preliminary work and the drilling of 45 wells, the Army Corps of Engineers is moving forward with solving the problem of a 10- to 15-mile-long plume of contaminated groundwater flowing from an abandoned missile site west of Cheyenne.

The next step is to set up a Restoration Advisory Board to get the public involved in the remediation phase of the Belvoir Ranch cleanup project.

Corps of Engineers and Wyoming Department of Environmental Quality representatives urged local residents Tuesday night to sign up for possible appointment to the advisory board.

The pitch came after an open house that allowed residents to question the scientists who have been working on the project and to receive information about what has been done so far and what options are available for future remediation.

Between 25 and 30 people attended the forum.

They also learned about the corps' construction of a treatment plant to clean up the contaminated water. The $5 million facility will be located next to the Cheyenne Sherard Water Treatment Plant and is scheduled to open by July.

The groundwater from the city's municipal wells at the Borie well field is are contaminated with trichloroethylene, or TCE, a solvent used to clean equipment at the Atlas Missile site west of Cheyenne more than 40 years ago.

The Corps is building the plant so the city can bring that groundwater into Cheyenne's water system.

The water will be treated through an air stripper process, which removes the contaminant by exposing the water to air.

The bigger problem is cleaning up the plume moving east from the old missile site.

“This is a very large, complex site,” said Jean Chytil of the Corps of Engineers office in Omaha, Neb. “There have been a lot of phases to data gathering.”

The cost of the options available range from $19.6 million to $1.5 billion.

The latter is a high-tech, in situ thermal treatment system that essentially boils off the chemicals in the water. It is expensive because of the energy used by the numerous electrodes needed to heat the groundwater.

“We think it would work, but it's almost to the point where it's impractical,” said Mark Selman of RMC Consultants, authors of the facility feasibility study.

The least costly option, at $19.6 million, and the one most favored, said Corps project manager Jeff Skog, is to intercept the plume in the middle as it comes down the hill and before it gets into the saturated Ogallala aquifer.

The water would be pumped into an air stripper. The cleansed water would be pumped back into the aquifer.

“It's important to make sure we're not impacting other people's wells,” Skog said.

An additional concern is that the plume changes direction.

“We are concerned because the plume is moving,” said a woman who resides in the area and declined to give her name.

She noted that the TCE from the missile site has been underground for years.

Contact Joan Barron at joan.barron@trib.com or 307-632-1244.

Contact Joan Barron at joan.barron@trib.com or 307-632-1244.

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