Nutrient removal and recovery from nitrogen- and phosphorus-laden waste streams in the form of struvite

For the purpose of waste conversion into resources, removal and recovery of nutrients from different scenarios of nitrogen- and phosphorus-laden waste streams in the form of struvite (MgNH₄PO₄·6H₂O, MAP) were presented in this paper. Nutrients-laden waste streams included urine, landfill leachate, industrial wastewater and the side streams in wastewater treatment plants etc. Batch experiments and software model were applied to obtain the optimal operational conditions. Several kinds of struvite reactors were introduced and compared. Under the optimal conditions, the recovery efficiency of NH₄⁺-N and PO₄³--P from urine separation could reach above 95% and 85%, respectively, while highly efficient recovery of nutrients was also realized for other kinds of wastewater. Some engineering examples on struvite crystallization were also discussed, indicating a feasible process for engineering application. Furthermore, the struvite recovered could not only be reused as a fertilizer, but also significantly reduce the organic load of wastewater treatment plants and improve effluent quality.