A look into the circularity of waste water sludge in Portugal: context, constraints and opportunities

The Portuguese action plan for the circular economy, proposes under action #6, the need to increase the efficiency of water use and reuse, as well as the improvement in the valorisation of nutrients present in waste water sludge. In 2014, last data available, only 52% of the sludge was subject to valorisation, indicating a significant room for improvement. This paper aims to analyse the potential for improvement in the quantity of sludge from WW subject to valorisation. To this end, the installed capacity to valorize sludge and its location is compared with the quantity of sludge produced and its location. Preliminary results indicate a clear mismatch between the distribution of installed capacity for biological treatment of WW-sludge and the distribution of waste water sludge produced.