Research of Carbon and Nitrogen Ratio and Sludge Stability in Aerobic Granular Sludge Bioreactor
In sequencing batch reactor aerobic granular sludge was cultivated, and the influence of influent C/N ratio to aerobic granular sludge was studied. The results showed that the granulation and the settling ability of the sludge were poor in high C/N, however, low C/N was beneficial to the accumulation of microorganism in reactor and MLSS could reach to as high as 8740 mg/L. Lower C/N ratio would lead to increase of particle size and disintegrate of loose structure and overgrowth on filamentous microbe, these were disadvantage of the stability of the system. It was not obvious that influent C/N ratio affected on the organic removal. The COD removal maintained at 87% after the preliminary form particles were formed in reactor. When C/N ratio was 100:15~100:35, the phosphorus removal efficiency was good. If C/N ratio was too high or too low, the formation of sludge granulation would be affected in the process. The influence of C/N ratio to ammonia nitrogen removal efficiency was obvious. While C/N ratio was 100:10, granular sludge had good simultaneous nitrification and denitrification performance, and the average removal of ammonia nitrogen attained to 91%. But low C/N ratio was able to inhibit the activity of nitrifying bacteria and denitrifying bacteria. At that time, ammonia nitrogen removal rate declined sharply in the system.