Montreal has it right on sewage dump plan, some experts say

Two different groups of scientific experts are offering limited support for the City of Montreal's plan to dump eight billion litres of sewage into the St. Lawrence River.

Engineers, biologists weigh in on plan to dump 8 billion litres of untreated waste into St. Lawrence

The City of Montreal plans to dump sewage water directly into the St. Lawrence River over a one-week period starting on Oct. 18. (Radio-Canada)

Two different groups of scientific experts have gone public with their positions on the City of Montreal's plan to dump eight billion litres of sewage into the St. Lawrence River, and they are offering limited support to the city's plan.

The city plans to shut down a major interceptor — a large pipe that feeds water from the sewers into the treatment plant — for maintenance for one week starting Oct. 18.

During that time, untreated water direct from the sewers would flow into the river.

'No other solution'

The controversy prompted a group of civil engineers from Montreal's École Polytechnique to release a "media guide" to explain the project.

Sarah Dorner, associate professor of civil, geological and mining engineering  and the Canada Research Chair in source water protection, told CBC Montreal's Daybreak that the city has no choice but to divert the wastewater into the river.

"There really is no other engineering or technical solution to this," Dorner said.

Dorner said the interceptor that's being closed is a massive and expensive piece of infrastructure that took years to build.

This is more than 30 kilometres long, up to five metres wide. There's a reason it took so long to build this. You can't just build that overnight.- Sarah Dorner , Canada Research Chair in source water protection

She said schemes to replace or bypass it temporarily are impractical.

"This is more than 30 kilometres long, up to five metres wide. There's a reason it took so long to build this. You can't just build that overnight," Dorner said.

As to suggestions that the wastewater be temporarily stored in tanker ships, Dorner said the quantity is such that the city would have to "build 26 ports" to dock the ships.

'No tremendous impact'

A group of water quality experts from nine Quebec universities also released a position paper on the plan.

Marc Amyot, a member of the Inter-university Research Group on Limnology and the Aquatic Environment and the director of the biological sciences department at Montreal University, told CBC Montreal's Homerun that the scientists wanted to speak out because they felt the issue was being overly politicized.

Amyot said untreated water already often flows into the St. Lawrence River when there's too much rain, when snow thaws, or when there are emergency breaks in the sewer system.

"This specific event will probably not have a tremendous environmental impact in itself because such events are already occurring," Amyot said.

He said there may be a short-term impact where some particulate matter from the wastewater could accumulate downstream, but he said major environmental damage is unlikely.

While he acknowledged dumping waste water is not ideal, Amyot said politicians should be more concerned with improving the city's overall filtration infrastructure for the long term than with this week-long sewage dump.

Not all experts agree.  

The Opposition Projet Montréal, which has criticized the plan, is scheduled to have its own biologist with a dissenting view at a news conference today.


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