QFT-robust control of a wastewater treatment plant

A QFT-robust control strategy is proposed to improve the performance of an activated sludge wastewater treatment plant (WWTP). The main control objective is to minimize the effluent nitrogen compounds (Ammonia and Nitrates simultaneously), rejecting the plant disturbances and insuring robust stability. The new strategy incorporates in the controller design the multivariable and nonlinear model n° l of the IAWQ for aeration tank reactions, calibrated with real data from the WWTP of Crispijana (Spain). The results obtained with the QFT controllers show a tighter control of the effluent nitrogen compounds and a significant reduction (energy saving) of the dissolved oxygen demand