Ammonium nitrogen removal from pharmaceutical wastewater by struvite precipitation

Abstract

The aim of the study is to investigate the removal efficiency of NH₄–N from pharmaceutical wastewater by struvite precipitation at different pH and Mg:N:P molar ratios. Both NH₄–N and PO₄–P removal were achieved by adding necessary amounts of Mg and P to pharmaceutical wastewater. It was found that the nutrient removal efficiency was affected by wastewater pH. When Mg:N:P molar ratio was 1:1:1, NH₄–N and PO₄–P removal efficiencies were 67.8% and 96.1% for MgSO₄ and 68.8% and 97.1% for MgCl₂ at pH 10.0. The increase in the molar ratio of Mg did not have a significant effect on NH₄–N removal. When Mg:N:P molar ratio was 2:1:1 at pH 10.0, NH₄–N and PO₄–P removal efficiency was 66.6% and 98.7% for MgSO₄ and 72.2% and 96.2% for MgCl₂, respectively.