Polyaniline improves granulation and stability of aerobic granular sludge

The polyaniline (PANI) material was used to enhance the formation process of aerobic granular sludge (AGS) in this study. The effect of PANI on the granulation and stability of sludge was investigated as well as the bacterial community of the formed AGS. The results showed that the PANI with the positively charged surface has a positive effect on microbial aggregation. The PANI added during the start-up period increased the retention of biomass, accelerating the granulation process of AGS. In addition, the PANI increased the pores and channels in AGS, favoring the long-term stability of the granules. It was also found that the PANI stimulated the cells to secrete polysaccharides, which facilitates to maintain the stability of AGS. The pollutants removal performance of the obtained AGS was investigated as well. Finally, the effect of the added PANI on bacterial communities in AGS was also assessed by high-throughput sequencing techniques.