The Jean-R.-Marcotte wastewater treatment plant, the largest in the world in terms of hydraulic capacity (maximum flow: 94 m³/s or 8,122,000 m³/d), plays a crucial role in the treatment of the City of Montreal’s wastewater. Commissioned in 1984, the plant was facing growing challenges, including aging incinerators and new regulatory requirements. These challenges led the city to consider innovative solutions for modernizing and optimizing sludge and wastewater treatment, while complying with new environmental standards. The aim of this ambitious project was to enhance the efficiency and sustainability of the facilities, while meeting the needs of the community.

Artelia was commissioned to carry out feasibility studies for the replacement of existing incinerators and the implementation of secondary treatment at the Jean-R.-Marcotte plant. We evaluated various technologies and proposed scenarios adapted to the plant’s specific constraints, such as limited space and variable flow rates. By studying hybrid solutions, we recommended a combination of incineration and anaerobic digestion, as well as thermal drying. In addition, we analyzed the addition of secondary treatment, investigating technologies such as biofiltration and suspended packing biological reactors (SPBRs), to achieve the objectives of phosphate removal and nitrogen reduction. Thanks to our expertise, we proposed a preliminary equipment design and detailed cost estimate, while ensuring optimal management of risks and operating costs to guarantee the long-term effectiveness of the project.