Evaluating the performance and microbial community of aerobic granular sludge under different salinities

Salt could affect the properties of aerobic granular sludge (AGS) and the biological treatment of wastewater. This study aimed to cultivate aerobic granular sludge under different salinity conditions (0,1 % and 3 %). The performance and microbial community profiles of AGS were studied to explain the effect of salinity. The presence of salinity led to more compact structure and smaller particle size of granular sludge. The experimental results indicated that 3 % salinity could seriously affected NH4+-N and TP removal efficiency of the reactor, while the impact on COD was negligible. Extracellular polymeric substance (EPS) played a pivotal role in AGS, especially TB-EPS. A large number of EPS producing bacteria existed in granular sludge regardless of salinity. However, there were significant differences in the AGS strains distribution with different salinities. The absolute dominant strain Thauera was observed at 1 % salinity, while the dominant strain Halomonas was prevailed at 3 % salinity.