The Doer government is forcing Winnipeg to spend $10 million to $50 million on a sewage-treatment process that one of the world’s leading freshwater scientists believes will actually make Lake Winnipeg filthier.
The city is in the midst of a $1.8-billion wastewater upgrade ordered up by Manitoba Conservation in 2003. While most of the money will buy new sewers, big vats of phosphorus-gobbling bacteria and tanks where toxic ammonia is turned into relatively harmless nitrates, one final step in the wastewater-treatment process — the breakdown of nitrates into a gas that can dissipate into the atmosphere — has come under fire from the former University of Manitoba scientist who helped discover how overfertilization kills freshwater lakes.
David Schindler, now an ecology professor at the University of Alberta, says there is no point removing nitrogen from the Lake Winnipeg watershed when phosphorus is the main cause of harmful blooms of potentially deadly blue-green algae.
The former Winnipegger says the city would be better off removing more phosphorus from its wastewater instead of removing nitrogen, a process that will cost the city $10 million to $50 million to put in place and may actually encourage the growth of more blue-green algae.
“I think it’s a waste,” said Schindler, the lead author of a new nutrient-reduction study compiled over 37 years, mostly by University of Manitoba researchers at the Freshwater Institute’s field station in the Experimental Lakes Area east of Kenora, Ont.
“I would much sooner see the money spent on attempts to restore the lake be (devoted) to phosphorus. All of the data supports that.”
But the NDP government steadfastly refuses to budge on its bid to force Winnipeg to remove both nitrogen and phosphorus, citing decades of research and the fact 13 cities in western Canada remove both nutrients from their wastewater.
“In the last 30 years, we’ve added both nitrogen and phosphorus to the lake, and now we have to undo that,” said Dwight Williamson, acting assistant deputy minister of Water Stewardship. “We cannot take half measures.”
Schindler, who first studied the effect of phosphorus on algae blooms in the 1970s, said provincial scientists and wastewater engineers have misinterpreted research conducted over the decades at the Experimental Lakes Area.
“They didn’t understand what the lake scientists were doing,” he said in a telephone interview. “The province is wrong. They’re misreading the evidence.”
His opinion is echoed by many local scientists and lake advocates and the city’s own wastewater engineers.
Biochemist Lyle Lockhart, a Lake Winnipeg Foundation board member, says it makes more environmental sense to only reduce phosphorus – and will cost the city less, to boot.
“Taking away the nitrogen supply doesn’t work and yet ratcheting down the phosphorus like they did in Lake Erie does work,” he Lockhart.
Water and sewer bills in Winnipeg have already risen 50 per cent over the past decade as a result of the wastewater upgrade, and are expected to double by the middle of the next decade. A fraction of the coming increase could be attributed to the contentious nitrate-breakdown process.
“We’re under an environmental order to make this happen, even though the science is questionable,” added Nick Szoke, acting branch head for water planning and project delivery for Winnipeg’s Water and Waste Department. “I totally agree with Schindler. Phosphorus is the key element …removing the nitrogen is not going to make that big a difference to the lake, but (city wastewater) is a controllable source.”
Williamson, however, insisted the province’s science is solid. He said the toxic blue-green algae that blankets Lake Winnipeg’s northern basin during the summer and the underwater varieties that clog fishing nets depend on nitrogen and phosphorus at different times in their life cycles. They feed off each other and spawn bigger algal blooms than either one could form alone, he said.
And the province has placed a priority on phosphorus removal, most recently in dishwasher soap and fertilizer, a fact that often gets overlooked in the academic debate, he added.
But the government won’t be swayed from its plan to demand nitrogen removal as well. And that has angered other politicians.
“It’s hard to argue with 37 years of research. Everyone seems to be on the same page except the government,” said Tory MLA and water critic Heather Stefanson.
“The premier has repeated the mantra, let’s listen to the scientists,” added North Kildonan Coun. Jeff Browaty, a Tory supporter. “Before we spend a crapload of money on this, we need to make sure the science is right.”
Why Nitrogen Removal Is Controversial
Lake Winnipeg’s pollution problem is primarily due to too much phosphorus and nitrogen.
The two nutrients come from a variety of sources, including city wastewater treatment systems.The nutrients cause algae to bloom, which die and then deprive the lake of oxygen as they decompose. That in turn changes the entire ecosystem of the lake.
To stop the degradation, the province wants to cut down on phosphorus and nitrogen loading. But many scientists disagree, because the worst algae – potentially toxic blue-greens – can get nitrogen straight from the air.
These scientists believe lower levels of nitrogen actually favour the blue-greens over less harmful varieties of algae, which can’t grab nitrogen from the air. So, the scientists advocate removing phosphorus alone.