ENHANCED NITROGEN REMOVAL BY AEROBIC GRANULAR SLUDGE AND EVOLUTION OF MICROBIAL COMMUNITY
To realize the efficient nitrogen removal of aerobic granular sludge(AGS),this study set an anaerobic section at the front end of the AGS system to form an anaerobic/aerobic(A/O)operation mode,to enhance the denitrification of the AGS system.At the same time,the changes in sludge characteristics and microbial community structure of AGS during the whole experiment were studied.The results showed that AGS was composed of filamentous bacteria as the skeleton,and the activated sludge continuously adhered to the skeleton under the action of hydraulic shear force to form AGS.During the process,the protein content in the extracellular polymeric substance(EPS)increased significantly,and the Zeta potential value of the sludge surface decreased,which improved the coagulation performance between the sludge and ensured the formation and stable operation of AGS.In the sludge granulation stage,the relative abundance of hydrophobic and EPS-secreting bacteria,such as unclassified_f_Sphingomonadaceae and unclassified_o_Saccharimonadales increased,which promoted sludge granulation.The intervention of A/O operation mode increased the relative abundance of nitrogen-related bacteria in the AGS system and enhanced the nitrogen removal performance of the AGS system.On the 110th day,the interventional AGS system in the low-temperature environment still maintained stable operation,and the final TN removal rate increased to 78.2％.The main reason was attributed to the increase in the relative abundance of Zoogloea(4.6％→8.2％),Thauera(2.0％→ 2.3％),Rhodobacter(2.3％→ 2.7％),norank_f_Actinomycetaceae(1.8％→ 3.7％),Pseudoxanthomonas(2.2％→4.5％),etc.
aerobic granular sludgemicrobial communitystrengthen denitrificationA/O model
NETL
NSTL
万方数据
