Experimental pilot activity to verify the anaerobic treatability of protein waste paste (pharmaceutical sector)

Objective

Experimental evaluation of the anaerobic treatability of waste protein pastes to verify the possibility of valorising these by-products through the production of biogas in co-digestion with sewage sludge and reducing the flow of solid waste disposed of externally.

Critical issues

High management costs associated with waste disposal.

Approach

• characterisation of substrates (pastes and sludges);
• anaerobic reactor management;
• monitoring of key parameters: HRT, OLR, specific gas production (SGP), VFA and TS/TVS;
• supernatant characterisation and dehydratability tests.

Results

The experiment demonstrated the technical feasibility of anaerobically co-digesting waste protein pastes with sewage sludge, showing good biogas yields and operational stability. However, seasonal variability must be taken into account. Anaerobic supernatant, which is rich in nitrogen and phosphorus, can be recovered to reduce the need for external nutrients in activated sludge biological treatment. This suggests a potential economic advantage that should be evaluated.