Research on Dissolved Oxygen Control during Biological Sewage Treatment

Abstract

This paper has put forward a dissolved oxygen control method based on MPC. The method has utilized the aforementioned simulation software package for generating large amounts of data, acquired state space model of the DO value process through identification, and simultaneously designed an MPC controller whose parameters are gradually determined by the common trial-and-error method. In simulation, it firstly carries out contrast verification of controller performance under different controller parameters so as to determine better controller parameters and lay the foundation for DO value process control. Secondly, it conducts control performance research on the activated sludge process by parameters-defined MPC controller and a comparison between built-in PI control strategies based on IWA and COST Benchmark. Results show that this controller performs better, and the DO value becomes more stable and less undulant. The proposed method has two advantages: first, fewer DO activities may make the activated sludge process more stable and reliable and thus lead to better processing effects; second, poorer DO fluctuations would exert little load for heating blowing machines, which is conducive to its energy-saving operation and consequently will provide conditions for low-cost operation of the whole activated sludge process.