Jean-R. Marcotte Wastewater Disinfection Upgrade

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The Jean-R. Marcotte water treatment station located in Montréal, Quebec is the third largest in the world. It treats 45% of all the wastewater produced in Quebec. The proper treatment of wastewater holds many benefits for people and the environment, especially at the scale this station required.

AtkinsRéalis work on upgrading the third largest municipal wastewater plant in the world carries tremendous benefits for both people and the environment.

Our role

AtkinsRéalis has played a key engineering and project management role in the addition of a world class ozonation unit to the treatment plant. It is one of the largest ozonation units in the world, disinfecting nearly 50% of Quebec’s wastewater. The facility will have the highest ozone production capacity globally, at 57 tonnes of ozone per day, treating up to 40 m³/s of wastewater, which is nearly equal to the volume of an Olympic-sized swimming pool every minute, or 1,382 Olympic-sized pools per day.

Our work has included:

Engineering design and construction management for the infrastructure upgrades;

Integrating the mechanical, electrical, and automation systems required for ozone disinfection; and

Coordinating with contractors and suppliers to ensure proper implementation of the ozone unit.

As the station treats so much of Quebec’s wastewater, it is classed as critical infrastructure, so the upgrade has been engineered and constructed to withstand both natural and man-made disaster scenarios so that water quality can be maintained. Our work included multi-phased construction with a temporary bypass channels and siphon systems, which added complexity to the project, but allowed the rest of the station to remain operational during construction. The engineering design is complex and includes buildings for both ozone and oxygen production, cooling systems, and an injection chamber. The entire project was modelled using advanced 3D software to create a comprehensive digital twin of the infrastructure.

As part of the project, we designed an energy recovery system that uses waste heat from the process to heat the buildings. The project also includes a pure oxygen production facility which provides oxygen to produce the necessary ozone. As the daily volume of oxygen required is so large (550 metric tonnes), this makes the facility more self-sufficient and cost-effective, since oxygen does not need to be bought and shipped to site.

“AtkinsRéalis is privileged to support the flagship wastewater disinfection project employing ozonation at the Jean-R. Marcotte treatment facility. Recognized as the largest initiative of its kind worldwide, this project is pivotal in advancing public health and environmental protection. Despite considerable construction complexities, innovative strategies have been deployed to address daily operational challenges and maintain progress toward completion.” - Sébastien Deshaies, Portfolio Director, AtkinsRéalis

An environmental milestone

The project is a major environmental milestone for Montréal, benefitting not only the City but also downstream communities that rely on the river for drinking water and recreational activities.

The upgraded plant will remove over 99% of bacteria and viruses, 75 to 85 percent of pharmaceutical residues, and significant levels (75 to 90 percent) of emerging contaminants. By reducing pathogens like bacteria and viruses and other contaminants, the project helps lower health risks for people living downstream.

This project ensures compliance with provincial discharge regulations, which helps the City of Montreal meet the current environmental regulations. This upgrade demonstrates Montréal’s commitment to sustainable development and climate resilience, aligning with global environmental goals.

Cleaner waterways benefit us all. Reducing pollution and improving the overall health of the St. Lawrence River is important for multiple reasons. People who live downstream and everyone who uses the river for recreation has safer water for drinking, as well as for recreation activities like swimming, boating, and fishing. A cleaner river does not only benefit people, however. It also benefits the wildlife and plants that rely on the riparian areas along the river for survival, as well as preserving and protecting the aquatic ecosystems that cannot exist without clean water, and that the river needs to remain healthy. Clean water keeps the St. Lawrence River and all the systems that depend on it in the proper balance.

Public health and environmental stewardship go hand in hand on this project and is a win for everyone.

99 %

of bacteria and viruses removed

45 %

of Montréal’s wastewater treated

57 tonnes

ozone produced per day

1,382

Olympic-sized pools worth of water treated per day

Water

Markets

Water
Location

Montreal, Canada
Client

City of Montreal

Sébastien Deshaies

Portfolio Director, Canada contact form

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Jean-R. Marcotte Wastewater Disinfection Upgrade

The Jean-R. Marcotte water treatment station located in Montréal, Quebec is the third largest in the world. It treats 45% of all the wastewater produced in Quebec. The proper treatment of wastewater holds many benefits for people and the environment, especially at the scale this station required.

Our role

An environmental milestone

Sébastien Deshaies

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