Phosphorus Recovery from Wastewater

Phosphate (P) fertiliser is a basis for global food production that cannot be substituted. Phosphorus rock from which P fertilisers are produced is a non‐renewable and limited resource and there is growing concern that it could become scarce at some time in the future. Wastewater is a major P sink and, during wastewater treatment, P is removed with the sewage sludge. The direct recycling of P through agricultural application of sewage sludge is becoming increasingly difficult and a growing amount of sewage sludge is incinerated and the contained P is lost as the ashes are disposed of Consequently, the recycling of P from wastewater, sewage sludge and sewage sludge ashes can contribute to conserve global P reserves.Starting from a discussion of P removal in wastewater treatment and the fate of P during anaerobic digestion and incineration, this chapter reviews various technologies that recover P from wastewater, sewage sludge and sewage sludge ashes. The feasibility of P recovery technologies depends on the P removal process applied during wastewater treatment. Together with the application points for P recovery (wastewater, sewage sludge and ashes), the theoretical P recovery potential, several technical processes, their advantages and limitations, and their developmental status (laboratory‐scale, pilot scale and large scale) are discussed.