[Aerobic sludge granulation and biological phosphorus removal in different operating conditions of SBR]

This paper investigate the effect of the different operating conditions on the aerobic sludge granulation and biological P removal characteristics in SBR by using synthetic domestic wastewater as feed. Different ratios of COD/TN (11.79, 18.85, 20.72, 24.66), COD/TP (27.85, 44.53, 48.93, 58.25), TN/TP (4.00, 2.36, 1.54), temperature(22 degrees C, 15 degrees C, 8 degrees C) and sludge retention time(16d, 10d, 5d) are tested in this process. It is found that the high ratios of COD/TN (24.66), COD/TP (58.25), temperature (22 degrees C) and low SRT (10d) are beneficial to the phosphorus removal and the cultivation of the aerobic granular sludge. The proper TN/TP rate (2.36), dissolved oxygen and selection of anaerobic seed sludge are basic requirement and most important factors to guarantee such aerobic granules in the process.