Utilisation of fish sludge and aquaculture effluent water from Norway for nutrient and energy recovery

This publication examines circular waste‑treatment solutions for the rapidly growing Norwegian aquaculture sector. It evaluates the environmental and economic performance of combining anaerobic digestion and microalgae cultivation to recover nutrients and energy from waste streams generated by a land‑based recirculating aquaculture system (RAS) producing 5,000 tonnes of salmon annually. 

Using life‑cycle and preliminary economic assessments, the research compares current waste‑handling practices with alternative valorisation pathways, highlighting the influence of energy demand, electricity mix, and co‑digestion strategies on sustainability outcomes and demonstrating the potential of circular approaches to reduce environmental impacts and operational costs in aquaculture.