Phosphorus Recovery from Synthetic Stormwater Using Iron- and Slag-Amended Green Infrastructure Soils

Abstract

The demand for phosphorus (P), fueled by the need for fertilizers to increase food production due to the ever-increasing population, is increasing P in the environment and diminishing global reserves of this nonrenewable resource. Stormwater runoff transports land-applied P into surrounding waterbodies. Green infrastructure (GI) soils are being engineered to target P removal from stormwater runoff. This research investigates the potential to recover P from engineered GI soils traditionally developed to remove P, contributing to the circular P economy by considering GI as a source of recoverable P. Batch experiments were conducted to determine the P removal performance of iron- and slag-amended GI soils. Next, amended soils were exposed to desorption solutions with pH 2 and 12 to determine the potential for P recovery. Finally, removal and recovery cycles were repeated using the same soils to determine the soil’s reuse potential. It was found that P could be successfully recovered from iron- and slag-amended soils. However, reuse of amended soils for P recovery was not successful because subsequent cycles offered poor P adsorption. Results suggest that recovery of P is ostensibly feasible from iron- and slag-amended GI soils.