Synthesis and application of magnetic PS@Fe3O4 microparticles for improving nitrogen removal in wastewater treatment process

This paper aims to improve the biological nitrogen removal performance by using magnetic polystyrene composite microparticles (PS@Fe 3 O 4 ). Three types of PS@Fe 3 O 4 with different surface morphologies were prepared by in-situ emulsion polymerization . Then, the optimum was creatively used as a biofilm carrier to form magnetic activated sludge (MAS) in lab-scale reactors. Compared to the conventional activated sludge , the utilization of PS@Fe 3 O 4 accelerated the sludge settling velocity to 0.76 m/h. In addition, the ammonium nitrogen removal, total nitrogen removal and simultaneous nitrification and denitrification improved by 7.08%, 24.27% and 19.53%, respectively. The dissolved oxygen concentration and pH were observed to reveal the effect of PS@Fe 3 O 4 on the nitrogen removal process. Based on microbial community analysis, there were more nitrifying and denitrifying bacteria in the MAS. Therefore, the novel developed PS@Fe 3 O 4 can be a promising utilization material as a biofilm carrier for biological wastewater treatment .