Integrating the Fe2+/H2O2-strengite method in airlift reactor for phosphorus removal and recovery from organic phosphorus wastewater

Abstract

Organic phosphorus (OP) pollution control and phosphorus resource recycling are essential for promoting ecological health and sustainable development. The development of an efficient strategy to remove and recover phosphorus from OP contaminations has garnered significant interest. In this study, we propose the integration of the Fe2+/H2O2-Strengite method in an airlift reactor (ALR) to enhance recovery product particle sizes and accelerate the settling process while achieving excellent phosphorus removal efficiency. In ALR, phosphorus is removed and recovered through the reaction with ferric salts, adsorption of hydrous ferric oxide, and flocculation of ferric salts. The unique liquid circulation within the ALR ensures a regular cyclic motion of product particles along the draft tube, promoting the agglomeration of microparticle into larger ones and reducing suspended microparticles. This internal circulation, combined with the presence of quartz as carriers, contributes to the production of recovery products with uniform particle sizes and enables a faster settling process. The resulting phosphorus recovery products consist of amorphous strengite analogue and goethite (FeOOH) mixed with phosphorus. Upon calcination, these products undergo transformation into crystalline FePO4 and Fe3PO7, thus facilitating phosphorus resource recycling. Notably, this high-performance phosphorus removal and recovery strategy for OP pollution yields valuable recovery products without causing secondary pollution, contribution to sustainable phosphorus resource management. This work offers valuable insights into addressing potentially competing challenges of resource depletion and environmental quality.