Control System Of SBR Wastewater Treatment Based On Parameter Self-adaptive Fuzzy-PID

With the rapid development of economy, we have to face the problem of environmental pollution. Environmental management especially sewage water treatment is the most important and the first priority in the succor, against resource-saving and environment-friendly society background. Sequencing batch reactor process is one of advanced sewage water treatment processes. But the key of applying the SBR process is its automation system which still has a lot of unsolved problems. So the research of auto-control of SBR process is very important.The Dissolved Oxygen (DO) is necessary for water quality evaluation. It is an important index in measuring organic materials pollution. Because of the characteristics of the biochemical reaction process in wastewater treatment, such as the inherent strong nonlinearity, delay and uncertainty; and Dissolved Oxygen (DO) control is the very important in biochemical reaction process, it's very difficult to control effective. Integrating the fuzzy control with the PID control, it will improve the adaptability of which, the system to the time-variation of the parameters and the change of conditions. It is used to adjust the parameters of PID control on-line in random environment, and good performance can be achieved even with object's interference.Combined the intelligence of fuzzy control with the reliability of PID control, the design introduces a fuzzy adaptive PID controller based on the analysis of DO control process theoy. Simulation results show that the fuzzy adaptive PID control system for DO Value in sewage water treatment has good control effects, which is an ideal intelligent control method. A fuzzy adaptive PID controller for DO is designed, in which the S7–224 CPU as its key pan of processor is used. The whole control system contains PLC, DO Detector, the inverter and fan turbine components. It accomplishes data acquisition of DO Value, the fuzzy adaptive PID control algorithm, on-line automatic control and serial communication with the monitor computer. And the monitor computer can display the field data, and manage the storage of historical records and the monitor of the whole system.Simulation result and field application show that control system response speed quicken after the parameter self-adaptive Fuzzy-PID controller being used. Over regulation measurement greatly reduce, transitional time shorten, fluctuation time decrease and control system possess rather strong robustness and good stability. It is an ideal intelligent control method. The whole system's effect of energy saving is satisfactory, after the inverter being controlled by using fuzzy control theory. It reduces roots blower's wear and tear for long service life, and realize good environmental and economic benefits.