Control Strategies of Low DO in Step-Feed Anoxic/Oxic Process Treating Domestic Wastewater for Filamentous Bulking Inhibition

Activated sludge systems operate at low DO concentration can save aeration energy and enhance the treatment performance. To explore the effect of DO control strategies on the settleability of activated sludge, different DO control strategies were carried out in a step-feed anoxic/oxic reactor treating domestic wastewater. The result shows that low DO concentration is not the single reason to filamentous bulking. To achieve long-term system stabilization and avoid serious filamentous bulking, feedforward-feedback DO control strategy may be a feasible and good choice.