11/10/2015 12:08 EST | Updated 11/10/2016 05:12 EST

Montreal Sewage Dump Begins Wednesday, Denis Coderre Says

MONTREAL — The City of Montreal says it will begin dumping eight billion litres of untreated sewage into the St. Lawrence River on Wednesday after it agreed to conform its discharge plan to the federal government's conditions.

Mayor Denis Coderre told reporters on Tuesday the dump will begin Wednesday morning at 12:01 a.m. and last about a week.

On Monday, Environment Minister Catherine McKenna said she would permit the dump as long as the city implemented a series of risk-mitigating measures to limit the effect of the sewage on the river.

Coderre says Montreal will meet all the requirements, such as keeping a closer eye on the discharge plume, creating an emergency protocol for unintended problems as well as clean-up plan for areas affected by the sewage.

Coderre maintains the controlled release of waste water is necessary in order to complete repairs on an aging interceptor sewer that feeds sewage to a treatment facility.

Part of the work includes relocating a snow chute.

"Nobody is pleased (but this is) the only option we had; this is the reason why (we have to dump the water)," Coderre told a news conference on Tuesday.

The project has been endorsed by experts from all levels of government who agree with Coderre that a planned and monitored discharge of sewage into the river is better than an unplanned one.

Should a sewer break during the winter, spring or summer months and leak untreated water into the river the toxicity could seriously affect fish reproduction cycles, scientists warned.

McKenna asked the city keep tabs on the water quality before, during and after the discharge and give the data to the federal government.

Citizens are being asked not to flush certain items during the dumping period such as condoms, medications and tampons.

Asked what Montrealers can expect to see and smell, Richard Fontaine, the head of city's waste water management, said there should be no noticeable impact given the colder water.

"You should have no odour and it'll be very hard to see something," Fontaine said. "There is a lot of monitoring that will be done to check exactly that, but in terms of what you'll see or what you'll smell, it won't be much different than today."

As of midnight, sewers will shut down valves and gates and divert what flows into the interceptor into outflow areas, Fontaine said, adding it will take eight-to-14 hours to dry out the sewer after which the infrastructure work will begin.

"Our maximum time frame is seven days, that is not negotiable," Fontaine said. "The objective is maximum seven and if we can do better, we will."

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