The state expects to release final details of plans to clean up groundwater contaminated by toxic coal ash at the Colstrip power plant next month.
Plant operator Talen Energy is on the hook to remediate groundwater contamination in and around ponds where it stores toxic coal ash leftover from generating electricity.
At an annual meeting Wednesday night in Colstrip hosted by the state Department of Environmental Quality to update the public, state hydrologist Sara Edinberg said DEQ and Talen are finalizing agreements about how and to what extent Talen will clean up groundwater and the coal ash ponds.
“I was just going to give a brief update on those and when you can expect to see revised versions,” says Edinberg.
The ponds span roughly 800 acres and are divided into three cleanup units. Some have been leaking sulfates, boron, cobalt, lithium, selenium, manganese, and potentially thallium and radium, into groundwater for decades.
Talen’s preferred plan for cleaning groundwater near newer Units 3 and 4 calls for flushing out contaminants using hundreds of injection and capture wells. Edinburg says contaminants will flush at different speeds but models show contamination plumes will be contained by a target date of 2049.
“All of the models show that has a lot of promise. It really does speed up the clean up time frame for those more stubborn constituents of interest,” she says.
Cleanup of the older ponds for Units 1 and 2 is trickier.
One clay-lined pond is in contact with groundwater, meaning that it’s still a source of contamination even though it’s no longer in use.
Edinburg says DEQ asked for Talen to address this Stage 1 pond separately from existing groundwater impacts to speed up the process.
“Whatever happens to the Stage 1 pond as far as source control goes, Talen still has to deal with the contamination that's already in the groundwater. So we didn't really see any reason to hold up remediation of the existing contamination because we haven't decided what to do yet with the Stage 1 pond,” says Edinberg.
Edinburg says groundwater cleanup will likely involve flushing. DEQ has asked Talen to consider a broader range of cleanup options for the Stage 1 pond, including replacing the clay cap, removing moisture from the pond and stabilizing the solid remainder, or excavating the coal ash entirely.
DEQ says Talen estimates remediating the three areas of coal ash ponds will cost $400 million to $700 million.
Earlier this year Talen unexpectedly announced it plans to close Units 1 and 2 by the end of this year.
Non-profit conservation group Northern Plains Resource Council has proposed a clean up plan for the ponds that it says would create more than 200 jobs for the next decade. Their plan, which would cost Talen Energy $900 million, calls for fully dewatering the ponds and putting the remaining solid waste in dry storage to prevent further groundwater contamination.
Retired Rancher and NPRC member Wallace McRae, who grew up in Colstrip, says Wednesday’s meeting is the first time he’s seen somebody on the state level trying to DO something positive.
“My cynicism creeps into it because a lot of it is too late. They can't recapture the stuff that's already gotten away,” says McRae.
Talen is set to submit final revised reports by the end of the month. A 30-day public comment period will follow.