Sensor-mediated control for aerobic granular sludge process treating mainstream anaerobic effluent
The aim of this study is to develop a sensor-mediated control strategy with an aerobic granular sludge reactor (GSR) for mainstream energy efficient nitrogen removal. A bench-scale aerobic GSR was constructed and operated for over 450 days while treating simulated effluent from a mainstream anaerobic treatment process. The reactor was equipped with sensor-mediated control via DO and NH4 + /NO3 - sensors, and operated using both a DO setpoint and an ammonium-based aeration strategy. In addition, a one-dimensional multisubstrate and multispecies biofilm model was developed to describe and evaluate the preformance of the reactor. The experimental and modeling results show that aeration was minimized by maintaining intermittent aeration with very low bulk DO < 0.5 mg/L and holding ammonium concentration at or above 5 mg/L as N. This allowed for stable nitrogen removal by outselecting nitrite oxidizing bacteria.
