Work at the Jean-R.-Marcotte wastewater treatment plant: news and impacts

Last updated August 10, 2022
Reading time: 2 min

The world’s largest ozonation unit is under construction at Montréal’s Jean-R. Marcotte wastewater treatment plant. Here’s the latest news on the project.

About the project


  • On the grounds of the Jean-R.-Marcotte plant in Rivière-des-Prairies
  • Île aux Vaches
  • Rue Sherbrooke East


Until December 2024


This huge project is divided into several phases. Each step was planned, in conjunction with the ministries concerned, to limit the impacts on the population and on recreational boaters, as well as on aquatic fauna and flora.

Project Schedule

First phase: work on the drainage canals

Until the end of October 2022

  • Construction of a temporary bypass canal to allow the plant to continue operating throughout the project
  • Connection of the bypass canal to the existing conduit
  • Work on the drainage structures located on Rue Sherbrooke East and on Île aux Vaches

November 2022 to April 2023

  • Construction of the western siphon
  • Redirection of treated water to the eastern outfall
  • Closing of the western canal and commissioning of the western siphon

November 2023 to April 2024

  • Construction of the eastern siphon
  • Redirection of treated water to the western outfall
  • Commissioning of the eastern siphon

Later phases

8 other phases of work will follow to construct the various structures and buildings comprising the ozonation unit.

Work Schedule

Monday to Friday from 6 a.m. to 5 p.m.
Evenings, nights and weekends, if necessary

Noise and odours

A certain level of noise may be generated by the work. Since the project includes removing components of the odour treatment system (permanent biofilters) this year, temporary biofilters will be installed to reduce odours that may persist near the plant.

Resident in the surrounding areas can report excessive noise or odours by writing to [email protected]. You will receive a form to fill out and return to the station so that the personnel in charge can deal with your complaint.

Notice of work operations

Consult the recent notices of work operations.

Quick search