Predictive functional control of dissolved oxygen with online estimation of oxygene uptake rate

Presented research relates to control of dissolved oxygen in a bioreactor. There were assumed a nonlinear relation between the volumetric oxygen transfer coefficient and air flow into the reactor. Thus the volumetric oxygen transfer coefficient was assumed as a substitute of manipulated value. Two control algorithms were considered for oxygen stabilization: classical PI and model predictive one - PFC. Both algorithms were tested with simulated plant and as a conclusion selective control concept for stabilizing dissolved oxygen concentration in bioreactor is proposed. One of the strongest disturbances is a change of nutrients load, while considering the wastewater treatment activated sludge. That change causes variations in oxygen consumption and in result destabilizes desired level of oxygen concentration. Thus for correct performance of model base controller, an estimation on-line procedure was applied.