Assessment of France's First Pilot Wastewater Treatment Plant for Nitrous Oxide Reduction

Through its Climate Plan (PCAET), Rennes Métropole has set an ambitious goal: to halve per capita GHG emissions by 2030. The sanitation department immediately emerged as a central lever for this plan, with a particular focus on reducing GHG at wastewater treatment plants. Beyond the historical balance between water quality and operating costs, the metropolis is already integrating carbon neutrality into the management of its facilities, thereby anticipating European regulatory developments in the sector (DERU 2).
The challenge of this approach revolves around nitrous oxide (N2O). This gas, generated in aeration basins, has a warming potential 300 times greater than CO2 and often accounts for the majority of the footprint.

Given the climate emergency, the metropolis's objective is clear:

• Massively reduce N2O emissions at the source,
• Ensure compliance with biological treatment,
• Manage the financial impact of this optimization.‍

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Rennes Métropole chose to integrate the Purecontrol solution to predictively manage aeration, thereby massively reducing N2O emissions while controlling discharge compliance and energy costs.

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