BILLINGS, Mont. (AP) — Montana regulators have given conditional approval to plans to inject clean water underground around the city of Colstrip to flush out water reserves polluted by coal ash from the small community’s namesake power plant, state officials said Wednesday.
Some details are still in the works, but pumping water into the 54 injection wells could begin by next year, said Sara Edinberg, a hydrogeologist with the Montana Department of Environmental Quality.
Leaking ash ponds at the plant operated by Talen Energy have contaminated groundwater in the area with boron, sulfate and other potentially harmful materials. Contaminated water seeps from the ponds at a rate of about 240 gallons per minute. That translates into more than 126 million gallons of polluted water annually.
The ash pond cleanup at Colstrip could cost an estimated $400 million to $700 million and is expected to last decades. It’s being carried out under a 2012 legal agreement reached by Talen’s predecessor, PPL Montana, and state officials.
Most Colstrip residents and businesses get water from the Yellowstone River. But some ranches rely on the underground water for their livestock.
The cleanup plan covers two of the power plant’s four units. Talen is required to post a $107 million bond to ensure that the work is completed.
Some of the pollution that’s deepest underground would not be pumped out under the plan approved Tuesday, and instead is expected to naturally decrease in concentration over time.
Talen would monitor the plume of pollution to make sure it does not become a risk to human health or the environment. If Talen can’t show that the plume is decreasing, state officials said they would require additional work to remove the pollution.
Company representatives did not respond by press time to email and telephone messages seeking comment.
Cleanup plans are still pending for the plant’s other two units, where the pollution is ongoing and expected to be more complicated to resolve.