Interval Analysis and Nonlinear Control of Wastewater Plants with Parameter Uncertainty
Authors: | Aschemann Harald, University of Ulm, Germany Rauh Andreas, University of Ulm, Germany Kletting Marco, University of Ulm, Germany Hofer Eberhard P., University of Ulm, Germany Gennat Marc, University of Wuppertal, Germany Tibken Bernd, University of Wuppertal, Germany |
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Topic: | 8.3 Modelling & Control of Environmental Systems |
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Session: | Modeling and Control of Wastewater Treatment Plants |
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Keywords: | Intervals, nonlinearity, uncertain dynamic systems, flatness-based control, water pollution |
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Abstract
This paper presents the successful application of interval arithmetics to a simplified activated sludge model that describes the reduction of biodegradable substrate in biological wastewater treatment. Reliable analysis of the steady-state behaviour as well as plant control have to account for the dominant uncertain system parameter given by the maximum specific growth rate of biomass. The proposed control strategy consists of nonlinear control of oxygen concentration using desired trajectories derived from interval evaluations of the uncertain steady-state substrate concentration. By this, plant operating costs can be significantly reduced resulting in superior plant efficiency.