Positive effects of magnetic Fe3O4@polyaniline on aerobic granular sludge: Aerobic granulation, granule stability and pollutants removal performance

Abstract

The magnetic material has been determined to have a positive effect on sludge granulation and wastewater treatment performance. In this study, the effect of magnetic Fe3O4@polyaniline (Fe3O4@PANI) on aerobic granulation, granule stability, and pollutants removal performance was evaluated by adding it into a sequencing batch reactor to cultivate aerobic granular sludge (AGS). The results indicated that the composite combined the advantages of PANI and Fe3O4 to promote the formation of AGS during the granulation period. The Fe3O4@PANI stimulated the granules to secrete extracellular polymeric substances with a higher proteins/polysaccharides ratio, thus enhancing the stability of the AGS. In addition, microbial community analysis revealed that the great performance of the AGS on denitrification and phosphorus removal could be attributed to the enrichment of denitrifying bacteria, phosphorus accumulating organisms (PAO), and denitrifying PAO by Fe3O4@PANI. Thus, Fe3O4@PANI has been demonstrated to have a positive effect on the formation and stability of AGS.