PID fuzzy control of activated sludge system

Activated sludge processes are complex bioprocesses. And these are hard to control because of the complex nonlinear and internal unstable behavior. In this paper, we propose a new two-dimension PID fuzzy controller to control the dissolved oxygen (DO) concentration. The proposed controller has two fuzzy controllers which are PI fuzzy controller and ID fuzzy controller. Through computer simulation the result shows that this PID fuzzy controller has stronger robustness and better dynamic characteristics compared with PI fuzzy controller and traditional PID controller.