The European Metropolis of Lille lays the foundation stone of the future Wattrelos–Leers wastewater treatment plant

The event brought together Damien Castelain, President of the MEL, Dominique Baert, Mayor of Wattrelos, Jean-Philippe Andries, Mayor of Leers, Isabelle Matykowski, Director General of the Artois-Picardie Water Agency, as well as representatives of the Saur group and its subsidiaries, including Élise Le Vaillant, Vice-President Saur France North-East, and Hugo Bardi, President of Saur Water Engineering and Stereau, alongside the member companies of the consortium designated to carry out the work, including NGE.

This highlight symbolizes the launch of a strategic project for the region, which is one of the largest modernization projects for a wastewater treatment plant in France over the next decade.

A major project for the ecological and climatic transition of the MEL

The Wattrelos wastewater treatment plant, commissioned in 1986 and renovated in the early 2000s, now treats wastewater from nearly 417.000 population equivalents spread across 15 municipalities in the MEL and the municipality of Mouscron (Belgium).

With this expansion-reconstruction project, its capacity will increase to 511.500 population equivalents by 2031, an increase of more than 20%.

The future station will offer increased performance:

• a treatment capacity increased from 3,3 m3/s to 10,3 m3/s thanks to the creation of a new line dedicated to rainy periods of 7 m3/s,
• a 30.000 m3 storage basin, the equivalent of 10 Olympic swimming pools, allowing for better management of heavy rains,
• the potential integration of the reuse of treated wastewater (REUT) for local uses, and exemplary landscape integration, with the creation of 4 hectares of flower meadows and the strengthening of the bocage framework to promote biodiversity.

The construction phase will be designed to limit the impact on the environment and local residents. A group of 20 to 40 residents will be involved to regularly discuss progress and provide feedback.

An exemplary station with positive energy

The new Wattrelos – Leers station is designed as a model of sobriety, performance and circular economy.

It will be a net energy producer thanks to a unique technological mix:

• the methanization of sludge from purification producing 11 GWh/year of biomethane, or the annual consumption of 2.800 inhabitants,
• an energy potential of dried sludge representing 14 Gwh/year.
• the recovery of fatal heat (2,2 GWh/year), covering the station's needs and equivalent to heating 1.500 homes,
• 6.000 m2 of photovoltaic panels and hydroelectric turbines covering more than 10% of electricity needs,

Furthermore, the station is supplied with 100% green electricity.

The station will thus become one of the largest positive energy stations in France, fully contributing to the objectives of the MEL Climate Plan and the decarbonization of essential services.

Respect for the environment and living environment

The treatment plant will incorporate innovative devices for the comfort and quality of life of local residents:

• capture and treatment of odors at source,
• containment of noisy equipment,
• supply of the process entirely with reused water,
• optimized sludge drying, reducing transport volumes by more than 1.000 trucks per year.

These developments will help limit nuisances, preserve resources and anchor the metropolitan policy of sustainable rainwater management, in line with the Local Urban Planning Plan and the fight against heat islands.

A large-scale project

The project represents a total amount of nearly 293 million euros:

• 200 million euros of investment for the works,
• 93 million euros for the operation for 12 years entrusted to Saur France.

The financing includes grants from the Artois-Picardie Water Agency (€45 million in grants and €30 million in repayable advances) and the ERDF (€6 million for the energy component).

The work is being carried out in stages to ensure continuity of public service:

• 2025: launch and preparatory work,
• 2026 – 2028: construction of new structures,
• 2029 – 2030: gradual commissioning,
• 2031: operation of the modernized station.

For Damien Castelain, President of the European Metropolis of Lille: "With this €200 million project, the European Metropolis of Lille is undertaking one of the largest wastewater treatment plant upgrades in France. This is a structuring project that will increase treatment capacity by 20% and guarantee a modern and efficient public sanitation service for hundreds of thousands of residents. Beyond the technical aspects, this project embodies our choice to invest in the future, to strengthen the attractiveness of our region, and to improve the daily lives of our residents. The MEL is setting an example by placing investment and innovation at the service of the general interest."

For Elise Le Vaillant, Vice-President of the North East region of Saur France: "With the European Metropolis of Lille, we are undertaking a project that concretely illustrates the water transition: a plant capable of treating the wastewater of nearly half of the region's inhabitants, while producing more energy than it consumes. It is a forward-looking project, designed to adapt to regulatory changes, climate hazards, and the needs of future generations."

For Hugo Bardi, President of Saur Water Engineering and Stereau: "The laying of this first stone marks the launch of a major project. Engineering, innovation, and consultation have come together to create one of the most efficient and exemplary wastewater treatment plants in France. This project showcases the expertise of our teams and the group's commitment alongside the MEL."

For Bruno Parent, Deputy Managing Director of the NGE Group: "This laying of the foundation stone symbolizes the launch of a major project for which the NGE Group is mobilizing its expertise in major civil engineering projects, acquired with numerous references in France and internationally. Alongside the MEL, elected officials, and our partners, we are contributing to the sustainable protection of water resources and strengthening actions for the ecological transition of the European Metropolis of Lille."

grouping

• Agent and operator: Saur France
• Purification engineering: Stereau
• Civil engineering: NGE GC, subsidiary of the NGE Group
• Architects: HB Architectes associés and Atelier 9.81
• Project management: Artelia

Total amount of the contract: nearly €300 million, including €200 million for the works and €93 million for the operation of the station over 12 years by Saur France.