Potential recovery of phosphorus in the portuguese urban sector: an opportunity for a critical raw materials supply?

Abstract

Phosphorus (P), which plays an important role in the food sector, is facing a global shortage. It has been identified as one of the materials at risk of scarcity, and in 2014 was declared as a critical raw material by the European Union. Studies indicate that the only way to close the P loop in the European Union is to recycle P from waste streams back into the food chain. In Portugal, the loss of P after wastewater treatment and landfilling has considerable value, motivating the evaluation of recovery and potential recovery of phosphorus. In addition, sludge from wastewater treatment plants (WWTP), which represents a specific flow of this sector, was also identified as having a high potential for P recovery. This work presents a preliminary assessment of the circularity of phosphorus in the urban cycle and the corresponding technical and political issues involved.