Effect of operating conditions on phosphorus recovery from acidified plant oil wastewater by struvite crystallization

Abstract

Struvite crystallization is an effective method for recovery of nitrogen and phosphorus from wastewater, and the operating parameters are crucial to the efficient phosphorus removal and struvite crystallization. In this study, the effects of pH, N-P ratio and Mg-P ratio on the phosphorus recovery from acidified plant oil wastewater were investigated. The results showed that the optimal operating conditions were pH 10, N-P ratio 1.1:1, and Mg-P ratio 1:1. Under the optimized operational conditions, 88.1% of the total phosphorus was removed from the wastewater. The XRD and SEM-EDS results indicated that the precipitate was struvite.

A Comprehensive Review on Wastewater Nitrogen Removal and Its Recovery Processes

“…Struvite is a white crystal compound that commonly accumulates in post-anaerobic digestion pipes in wastewater treatment plants (WWTPs) [ 50 ]. Struvite is formed when magnesium, ammonium, and phosphate that are in equimolar concentrations in waste water [ 51 , 52 ]; the chemical reaction equation is as follows (Equation (1)): Mg 2+ + NH 4 + + PO 4 3− + 6H 2 O⇋MgNH 4 PO 4 ·6H 2 O↓ S = 0.169 (g/L) …”