Just remove phosphorus from city effluent: top scientist

February 25, 2010

ONE of the planet’s leading freshwater scientists says his life’s work has been ignored or misrepresented before Manitoba’s Clean Environment Commission.David Schindler, a University of Alberta limnologist who founded the Experimental Lakes Area in northwestern Ontario, told an audience of city and provincial officials on Tuesday that there is no scientific basis for an environmental order that requires Winnipeg remove nitrogen from its treated sewage as well as phosphorus.

Speaking at city hall at the behest of Winnipeg Mayor Sam Katz, Schindler said he believes key ELA findings about the effects of nitrogen removal were misrepresented to the Clean Environment Commission, the provincial agency that ordered Winnipeg to upgrade its sewage treatment in 2003 and has been monitoring the multibillion-dollar effort ever since.

The city and province are embroiled in a dispute over the provincial order to remove nitrogen, a step the city claims will cost $350 million up front as well as an additional $9 million a year.

Schindler and dozens of other current freshwater scientists say that move will do more harm than good to Lake Winnipeg, which is suffering from the effects of eutrophication, a process by which excessive amounts of phosphorus and nitrogen from a variety of human sources spawn the growth of algae, which in turn deprive the lake of oxygen as they decompose.

Since the majority of the algae growth in Lake Winnipeg involves blue-green algae, which are capable of getting nitrogen from the air, it is pointless to limit the amount of nitrogen flowing into the Lake Winnipeg watershed right now, Schindler said.

Limiting phosphorus alone will have a greater effect on algae blooms, he insisted, adding claims to the contrary by other researchers are akin to climate-change denials.

“They have a couple of other people out there who keep dithering on about all this other information about there,” he said, declining to name the scientists in question.

Clean Environment Commission chairman Terry Sargeant, who took in the speech, said he does not dispute Schindler’s science or the wisdom of limiting phosphorus to prevent blue-green algae blooms.

Sargeant said the commission was concerned about more than blue-green algae when it ordered the city to remove nitrogen as well as phosphorus. But he said the commission is considering a city request to convert ammonia, a nitrogen-based compound toxic to fish, into nitrate chemicals, without removing the nitrogen.

Schindler also said he thought the CEC lacked the expertise to review freshwater science, but a spokeswoman for the Selinger government expressed confidence in the commission.

The Tory opposition, meanwhile, issued a statement lambasting the NDP government for ignoring the financial and environmental concerns about the expense of nitrogen.

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Republished from the Winnipeg Free Press print edition February 24, 2010 B2

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