Stereau and Enosis join forces to integrate biological methanation into the wastewater treatment plants of tomorrow

Conventional methanization produces biogas composed of approximately 60% methane and 40% CO₂, of which only the methane portion can be recovered as energy. The biological methanation developed by Enosis goes one step further: it combines this CO₂ with green hydrogen to produce additional methane. This reaction, which is at the heart of power-to-gas processes, uses hydrogen produced by electrolysis from green electricity to convert unused CO₂ into renewable or low-carbon methane.

The biological methanation developed by Enosis thus increases renewable gas production by 30 to 50%, while eliminating CO₂ emissions.

Available in modules, skids, or containers, Enosis technology integrates seamlessly with the urban constraints of wastewater treatment plants. It offers several advantages for local authorities:

• Easy integration, even on sites with limited space;
• Small footprint, suitable for urban environments;
• Robust operation despite variations in biogas quality;
• Gradual ramp-up according to needs.

The recovery of biogenic CO₂ from wastewater treatment plants is a strategic lever for local authorities, which are required to improve the energy and climate performance of their facilities under the new European Urban Wastewater Directive (Directive européenne sur les Eaux Résiduaires Urbaines – DERU). The directive introduces stricter requirements for emissions reduction, energy efficiency, and the use of renewable energy in wastewater treatment infrastructure.

By transforming a gas that was previously discarded into renewable methane, biological methanation directly addresses these new requirements: it increases local green energy production, improves the carbon footprint of treatment plants, and contributes to achieving European climate neutrality targets.