INTERVAL ANALYSIS AND NONLINEAR CONTROL OFWASTEWATER PLANTS WITH PARAMETER UNCERTAINTY

摘要

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.