Analysis and succession of nitrifying bacteria community structure in sequencing biofilm batch reactor

To reveal the succession procedure of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) community structure in sequencing biofilm batch reactor (SBBR), the molecular biological techniques of denaturing gradient gel electrophoresis (DGGE), cloning, and real-time PCR were applied. DGGE showed that the structural diversity of the bacterial community increased during the biofilm formation period, and some kinds of populations had been highly preponderant consistently. The results of cloning and sequencing revealed that Nitrosomonas was the dominant species. The real-time PCR analysis indicated that the amount of the AOB increased significantly after the cultivation period, and the NOB gradually decreased. The AOB content on the 25th day was 17 times that of the 6th day. It also showed the biofilm formed successfully with accumulating nitrite and prepared to achieve the achievement of simultaneous nitrification and denitrification in SBBR. Furthermore, the ammonia-oxidizing rate was in correspondence with the NH4 (+)-N removal efficiency.