The modelling and sliding mode control study of sewage treatment system

This paper deals with the problem of modeling and sliding mode control study of the sewage treatment system. Firstly, according to reaction mechanism of microorganism and Activated Sludge Models 1 (ASM1), the mathematical modeling of sewage treatment system is established. Then the original model was simplified to get a new activated sludge model to better understand the response of activated sludge wastewater treatment process and how various factors affecting the final treatment variations. Secondly, for the model with large internal parameter perturbation and external disturbance, the sliding mode function and sliding mode controller are designed. The asymptotically stability of the closed-loop system is proved by Lyapunov stability theory and linear matrix inequalities toolbox. Finally, the simulation is done to verify the efficiency. According to the simulation result, under larger internal parameter perturbation and external disturbance, all trajectories are still convergent to zero fast , and the sliding function of the system is convergent to zero. It shows the system has good robustness.