Recent technological developments and challenges for phosphorus removal and recovery toward a circular economy

This review aims to summarise the current state of the art technologies for phosphorus recovery from waste and wastewater. Information corroborated here shows a clear relationship between PO4-P content in the liquid phase and the cost of phosphorus recovery. In fact, all current commercial scale operations in this review involve a phosphorus-rich waste stream. In most cases, phosphorus recovery is achieved via two key steps: solubilising phosphorus into water and then phosphate recovery via chemical precipitation/crystallisation. Recent development has also included enrichment and pre-treatment of the phosphorus rich liquid stream. Phosphorus is also a contaminant in the aquatic environment. Thus, this work also reviews the post-treatment of the liquid stream after phosphorus recovery for environmental discharge or water reuse. This review places a spotlight on the requirement for further research work especially on phosphorus enrichment at pilot- and full-scale level. The review also demonstrates the need for further research on pre-treatment and post-treatment to complement the recovery process via chemical precipitation.