Research On AAO Process Aeration Control System Modeling And Control Strategy

In order to protect the limited freshwater resource, we should develop sewage treatment business in China.Anaerobic-Anoxic-Oxic process is one of the mature sewage treatment processes and it suits our country. The key of the process is its aeration system, which still has a lot of unsolved problems due to its complexity biological treatment process. So, It is very important.to do the research of auto-control of aeration system.The aeration system of Anaerobic-Anoxic-Oxic process is a complex process that has characters of uncertainly,nonlinearity,coupling and changes with time. The tradition control method can't be applied in the process due to the lack of the accurate math model of the process and the sensors which can reflect process parameters directly. The paper applies the fuzzy control with PID which is one of intelligence control methods to aeration control system of sewage treatment to improve the efficiency and decrease the consume of energy.The paper analyses the parameters that affect the process of aeration system,and dissolved oxygen is used as the feedback signal of control system. Then establish the model basing on the relationship of parameters of the aeration system.Design PID,fuzzy and fuzzy-PID controller,and use Matlab software simulation and compare three controllers,then determine fuzzy-PID control method is the most proper control strategy.Finally the fuzzy-PID controller applied to the project of NingBo XinZhou sewage treatment plant aeration control system.Make analysis the changing trend of dissolved oxygen and other control parameters in running process of aeration control system,to verify the fuzzy-PID control strategy effective,reasonable.