Analysis Of The Functional Microorganisms For Nitrogen Removal And Microbial Community Dynamics In Aerobic Granules

Aerobic granular sludge has great applicable values in wastewater treatment due to it's advantages, such as excellent settling ability, high biomass retention and shock loading resistence ability. With aerobic granules, nitrogen removal by simultaneous nitrification denitrification (SND) can be achieved, whereas, up to now most research focused on low-concentration ammonium wastewater or artificial domestic wastewater treatment by this process. Therefore, this research was conducted in analyzing the functional microorganisms and microbial community of aerobic granule.The sludge samples taken at different phases of aerobic granules were analyzed by Denaturing Gradient Gel Electrophoresis (DGGE). The results revealed that ammonium-oxiding bacteria included autotrophic nitrifier Nitrosomonas and heterotropic nitrifier Paracoccus denitrificans. Although Nitrosomonas enriched in the process of aerobic granule forming, heterotropic nitrifier Paracoccus denitrificans was the dominated genus of the reactor because autorophical nitrite-oxiding bacteria grew slower than ammonium-oxiding bacteria at 25oC, nitrite-oxiding bacteria disappeared after a short time enrichment. Denitrifier in the reacter were Paracoccus denitrificans, Rhodobacter and Thauera sp.. Paracoccus denitrificans, Rhodobacter and Thauera sp. are aerobically respiring bacteria that under anoxic conditions have the ability to switch to anaerobic respiration.The populations in the reactor varied obviously during the whole aerobic granule forming. Certain bacteria enriched and others disappeared. The functional microorganisms and filamentous bacteria were found enriched. Streptococcus and Bacteroidetes enriched after aerobic granule forming which revealed anaerobic aera existed...