CEBEDEAU • Small-scale Biométhanisation

Water Circularity & SMEs: for innovative, circular, and accessible sanitation

Part of the SWaM@Sc portfolio led by ULiège and CEBEDEAU, the Water Circularity & SMEs project aims to reinvent small-scale wastewater treatment in the SME and small community sector.

Its ambition ? To transform sanitation into an opportunity by using appropriate technologies that maximize the recovery of by-products (treated water, energy, materials).

Why this project?

Today, small-scale wastewater treatment often remains a technical, regulatory, and financial constraint. SMEs, micro-enterprises, and small communities are rarely equipped to recover value from their effluents: the water is purified… then discharged, with little or no recovery of energy or materials.

Yet this wastewater has great potential: energy, reusable water, recoverable materials… By treating it differently, we can turn an obligation into an opportunity.

Focus on small-scale biomethanization

One part of the project is the biomethanization of liquid effluents from agri-food SMEs. This water, rich in biodegradable carbon, offers great potential for methane production. On average, more than 10% of an SME's thermal/electrical energy needs can be covered simply by recovering its wastewater!

The preferred technology is the baffled reactor (ABR), a robust, simple process suited to effluents loaded with suspended solids (SS) typical of this sector. To maximize its performance, the project is exploring several avenues for optimization:

• Biomethanization at room temperature (20-28°C) in (micro)breweries: despite slower degradation, the savings on heating more than compensate for this.
• Treatment of fatty substances: highly energetic but complex to hydrolyse, they require adaptations such as enlarging storage chambers, mechanical breaking of scum or enzymatic pre-treatment.
• Management of high TSS loads: optimisation of hydraulics and primary settling to improve capture and degradation.

A 700-liter pilot reactor divided into three chambers allows these adaptations to be tested under real conditions.

Towards a new vision of sanitation

Through this project, Eau-Circularité & PME is proposing a circular, integrated, and pragmatic approach to small-scale sanitation. This approach combines technological innovation, environmental efficiency, and economic viability for SMEs—with a clear desire to change existing practices and legislative frameworks.