Using Specific Oxygen Rate As Warning Index Of Sludge Bulking And Its Application

This paper aims to apply an efficient way to warn the filamentous bulking through studying the change of bacteria activity before the active sludge bulking. By limiting the concentration of dissolved oxygen, one common factor which always lead filamentous bulking, and recording the oxygen uptake rate during the whole bulking duration, an easy way to alert filamentous bulking has found. Meanwhile, same situation was established to test whether this early warning mechanism can be affected by the state of active sludge. Finally, in the one Wastewater Treatment Plant, this early warning mechanism was utilized to examine whether it is applicable in practical circumstances. This study aspires to offer an easy way to ameliorate the WWTP system and help the technician to predict and prohibit filamentous bulking.Achievements in this study:1) During the experiment, filamentous bulking has been successfully achieved in every different reactor through limiting the concentration of dissolved oxygen. By recording the specific oxygen uptake rate(SOUR) before and after filamentous bulking,it is found that the SOUR will always clime and peak before the filamentous bulking. It is supposed that the rapidly climbing SOUR is the main cause of filamentous bulking and SOUR can be utilized to forecast filamentous bulking. This early warning system would not fail in any state of active sludge.2) During the experiment, the corresponding time between SOUR peaking and filamentous bulking is tremendous different. This corresponding time is ranging between 8 to 42 days. It is analyzed to separate this range to fast responding time and slowly responding time by 25 day. While the faster SOUR increasing, the responding time is longer, filamentous bulking is postponed.3) By recording the SOUR of active sludge in one Wastewater Treatment Plantwhile filamentous bulking was taking place, it was showed that 5~10 days after the SOUR peaking filamentous bulking occurred. Therefore, using the SOUR peaking of active sludge as an early warning sign of filamentous bulking has been successfully tested in the practical circumstances.