Nitrogen under sewage treatment plant plan microscope
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A narrowed approach to upgrades at Winnipeg’s largest sewage treatment plant could save hundreds of millions of dollars and reach targets to reduce its pollution years earlier, according to supporters.
But not everyone is convinced there’s enough evidence to ensure the change to the $1.8-billion north end sewage treatment plant upgrade will fully address algae blooms that sometimes cover Lake Winnipeg.
At Thursday’s city council meeting, Coun. Matt Allard raised a motion that calls for a provincial task force (recently created to help ensure the entire upgrade is completed as soon as possible) to review whether or not to remove a requirement to drastically reduce the amount of nitrogen in effluent leaving the plant.
The province has ordered the City of Winnipeg to greatly reduce both algae-promoting nitrogen and phosphorous from the plant. However, some scientists believe phosphorous alone is the key culprit.
“The new consensus seems to be that there is no link between nitrogen in the water and toxic algae blooms. Toxic algae gets (its) nitrogen from the air. In terms of cost, in terms of process, I think it’s time to review what is one of the biggest infrastructure projects in the history of Winnipeg, because it will have a massive impact per person, per taxpayer,” Allard told reporters.
Ideally, Allard said he’d also like the province to require the city to meet its phosphorous reduction target during the second phase of the three-phase sewage upgrade, arguing relying on a chemical process to do so could achieve that goal years sooner.
“If we had new information, why would we spend hundreds of millions of dollars on something that we don’t need to save Lake Winnipeg?”
There is no clear funding agreement or timeline for Phase 3 of the upgrade, while the city hopes to begin construction on Phase 2 in 2025, and complete it within the following five years.
Council’s water and waste chairman said the change is worth exploring since the third “nutrient removal” phase of the north end upgrade was estimated to cost $828 million in 2019, and its price would likely be even higher now.
“Do we need to go after nitrogen? I think that’s a fair question. I’m not enough of a scientist to answer that but I think that’s a valid point (to explore) before a billion-dollar project,” said Coun. Brian Mayes.
Council has also been warned the second “biosolids facilities” phase of the upgrade could see the megaproject’s price tag soar by another $360 million to reach just over $2.2 billion overall.
Mayes said narrowing the focus to phosphorous alone could produce significant savings. “I don’t know if we can skip it entirely, but I think we could massively simplify Phase 3 (of the project), if not avoid it altogether.”
Both Mayes and Mayor Scott Gillingham noted there has been extensive debate among scientists about the role nitrogen plays in algae growth ever since the province first ordered the city to reduce the plant’s pollution in 2003.
“I think Coun. Allard a few times today has presented things as simplified and they’re not… I’d need more discussion, more evidence (from) experts on this,” said Gillingham, noting he is open to exploring the idea.
Meanwhile, a key advocacy group supported the motion.
“Nitrogen has no effect on algal blooms on Lake Winnipeg… What we want is for the city and the province to accelerate phosphorous compliance using a more cost-effective solution that will get us to a positive environmental impact sooner,” said Alexis Kanu, an environmental scientist and executive director of the Lake Winnipeg Foundation.
“If we step back and re-evaluate Phase 3, that means that we may potentially be saving the cost of that entire third phase.”
However, city water and waste officials say Winnipeg’s current wastewater licence also requires it to remove ammonia (which is toxic to fish) and use a biological process, not just a chemical one, to remove phosphorous. Those two processes would also remove some nitrogen, since ammonia is a nitrogen-based compound, the city says.
Should those two steps still be required by the province, there wouldn’t be “any significant benefit to eliminating the requirement to reduce total nitrogen,” spokeswoman Lisa Marquardson said in an emailed statement.
Since the province has not altered the requirement to remove both nitrogen and phosphorous, the city doesn’t have an estimate on how much money or time could be saved by eliminating work to reduce nitrogen, Marquardson added.
Allard’s motion will be considered by council’s water and waste committee in May.
Born and raised in Winnipeg, Joyanne loves to tell the stories of this city, especially when politics is involved. Joyanne became the city hall reporter for the Winnipeg Free Press in early 2020.