The Montana Department of Environmental Quality (DEQ) expects limited impacts after a power failure at the Columbia Falls Wastewater Treatment Plant discovered last week led to between 150,000 to 200,000 gallons of partially treated effluent being put into the Flathead River.
“The long-term impacts are not anticipated to be major,” said Moira Davin, a public information specialist with Montana DEQ. “Because the flow from the Flathead (river) was large in comparison to the wastewater discharged.”
According to a noncompliance report city officials submitted to the state agency, the power failure occurred last week due to a malfunction with the system’s main breaker. The breaker manufacturer is investigating the failure, according to city officials, which they described as an “extremely rare occurrence.”
DEQ received the noncompliance report this week from Columbia Falls Waste Water Treatment Plant Manager Grady Jenkins. The report, which the city is required to submit, is meant to provide the state agency with additional information about what prompted the failure and what steps are being taken to “reduce, eliminate and prevent reoccurrence of the noncompliance.”
Still, DEQ has requested the city provide additional information about how much effluent was diverted, how much was discharged and the results of initial water quality monitoring reports.
“We are just looking for some more specific details,” Davin said. “They have been in great communication with our team.”
Asked whether the city could face fines, Davin said the agency’s overarching goal is to identify what steps the city should take to avoid another incident.
“Our goal really is to get them into compliance and to make sure that this doesn’t happen again,” Davin said.
The power outage began at 4 a.m. on Monday, Aug. 15, and power was restored by 11 a.m. the following day. Chris Hanley, the public works director for the city of Columbia Falls, said the outage led to higher levels of phosphorous and nitrogen in the effluent, or discharged liquid waste, that was released into the river from the plant. During the outage, the city did advise people “out of an abundance of caution” to avoid being in the river near where the treatment plant was discharging effluent, according to a city public service announcement.
“At no time was raw sewage injected into the river,” the announcement says.
According to the noncompliance report, an E. coli grab sample taken on Aug. 16 at 7:10 a.m. was 21.6 MPN(most probable number)/100ml.
Hanley said his staff conducted some testing since power was restored and they found that the levels of phosphorous in the effluent at the plant were near the normal levels DEQ requires. The treatment plant is working with DEQ, and they’re also in the process of looking into any possible additional steps that might need to be taken to avoid a repeat of this in the future, according to Hanley.
Stressing that the findings were still preliminary, Hanley said an electrician the city works with at the plant believes the outage was caused by an uncommon type of breaker failure.
“Breakers are meant to trip, and then you can reset them,” Hanley said. “This one just melted down. He’s never seen this before, and he’s been an electrician his whole life. He said it’s extremely rare.”
Additionally, Hanley said the city has reached out to the breaker manufacturer about the problem.
“This is something that has never happened at our plant,” he said.
The effluent, or liquid waste, that was released was treated with ultraviolet lights that the plant uses to kill E. coli and other bacteria as part of its treatment processes, according to Hanley. The ultraviolet treatment building at the plant relies on a different power source than the other part of the plant where the power failure occurred, and so the UV treatments were unaffected by the outage. Additionally, Hanley said that the gravity-based system the plant uses continued to allow for ample space and time in which solids could separate from the effluent and settle as the waste moved through the plant.
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