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Aerobic granular sludge compared with conventional activated sludge, the sludge has compact structure, microbial content, resistance mutations on the quality and quantity of good performance, handling toxic waste, sedimentation performance is good, the water purification process is simple, the sewage treatment process can be eliminating the need for secondary sedimentation tank and sludge return equipment, small footprint, investment and operation and management costs low. Heterotrophic denitrifying bacteria to complete the nitration reaction may be either a substrate of organic nitrogen can also be inorganic nitrogen. Most of heterotrophic nitrifying bacteria at low dissolved oxygen and high organic carbon concentrations in environments simultaneous nitrification and aerobic heterotrophic denitrification, the release of N 2 , NO or N 2 O and so on. Therefore, nitrification denitrification process did not produce NO 2 - and NO 3 - accumulation of heterotrophic nitrifying bacteria can maintain a high activity, denitrification effect. In this experiment, SBR reactor, the influent wastewater using artificial (beer as a carbon source, NH 4 Cl as nitrogen source), facultative bacteria inoculated sludge mostly using activated sludge, By constantly reducing sludge settling time making selection pressure cultivate aerobic granular sludge. For heterotrophic nitrifying bacteria in the sludge system dominated early experiments run alternately in anaerobic and aerobic way screening enrichment facultative bacteria. And in accordance with the growth of heterotrophic nitrifying bacteria need to control influent COD, NH 4 -N concentration and system DO (DO) were 1000mg / L, 200mg / L , 2.0mg / L (as the mud stage temporarily increased to 6.0mg / L). The final form of aerobic granular sludge mostly in the 0.5 ~ 3.5cm diameter between the sludge volume index (SVI) in 25ml / g or so, mixed liquor suspended solids (MLSS) at 5900mg / L or so. The experimental cultivation of aerobic granular sludge to the dominant heterotrophic bacteria nitrifying bacteria and aerobic granular sludge structure is relatively loose, higher porosity. The special structure of granular sludge and its dominant bacteria specific denitrification pathway, strengthened its simultaneous nitrification and denitrification effect. Aerobic granular sludge performance and stability, the system for COD, NH 4 -N and TN removal rate reached 96.1%, 95.4% and 85.7%. In this study, cultured for aerobic granular sludge COD and NH 4 -N removal and general aerobic granular sludge same, much better than the TN removal ordinary granular sludge.
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