The City of Winnipeg faces up to $1.5 million in fines for releasing partly treated sewage into the Red River during last year's bioreactor malfunction at the South End Water Pollution Control Centre.
During a month-long period in October and November 2011, the second-largest of the city's three sewage-treatment plants discharged 50 million to 60 million litres of partly treated sewage into the Red River every day, leading to elevated downstream levels of fecal bacteria and ammonia.
The sewage was released for seven weeks, including several weeks with low discharges. But the city failed to report the malfunction to the province until three weeks after engineers first noticed a problem at the plant.
The province charged the city under the Environment Act for the release after almost a year of investigating. It issued recommendations in an effort to prevent similar bioreactor malfunctions.
Conservation Minister Gord Mackintosh said Manitoba Justice prosecutors made the decision to go after the city.
The decision was independent of politics, he said.
"The Environment Act has provisions to protect the province's waters and Lake Winnipeg," Mackintosh said Thursday. "It requires accountability of those who are assigned to provide that protection. It's a prosecution decision based on the law and the evidence. It applies to everyone, including municipalities like the city."
The problem started on Oct. 7, 2011, when engineers found the biological-treatment component of the plant failed due to the unexplained death of beneficial bacteria that normally consume organic waste. At the same time, undesirable bacteria grew in the bioreactors and interfered with the clarification of effluent further along in the treatment process.
More than three weeks after the malfunction began, engineers disclosed the problem to politicians and sought advice from outside experts. To kick-start the bioreactors, the city trucked in beneficial bacteria from the North End Water Pollution Control Centre. Engineers also used chlorine to kill the undesirable bacteria and added a polymer to a clarification tank to help settle waste particles.
City engineers theorized that illegal dumping of chemicals into the sewage system may have led to the death of the beneficial bacteria at the plant. But the city never identified the culprit, Winnipeg's water and waste director Diane Sacher said Thursday.
Neither did the provincial review released on Thursday, which includes recommendations to immediately report future releases and establish a means of dealing with bioreactor problems.
The city put in place those measures almost immediately after the bioreactors started working again last November, said Sacher, adding she has had little dialogue with the province since it conducted an investigation shortly after the incident.
Dan McInnis, a former city solid-waste manager who's now assistant deputy minister with Manitoba Conservation and Water Stewardship, said the city knew charges would be laid.
The city faces one charge of releasing a pollutant, one charge of releasing a pollutant at a level that exceeds its licensed limit and one charge of failing to report the release.
"What our review found is the city didn't even follow its own reporting requirements," McInnis said.
"They have an emergency-response plan, what they're supposed to do, and they didn't even follow their own plan."
If convicted, the city could face a penalty of up to $500,000 on each of the three charges, McInnis said.
The city faced similar charges under the federal Fisheries Act following a 2002 mechanical malfunction at the North End Pollution Control Centre caused 427 million cubic metres of untreated, unfiltered sewage to pour into the Red River. The Crown dropped the charges in 2005.
But the 2002 spill led the province to order sewage-treatment upgrades now expected to cost more than $2 billion.