Research On The Fuzzy Adaptive PID Control System For PH Value In Wastewater Treatment

With the development of industry and the increasing of urban population, the wastewater treatment is being given more and more attention. It's very important to control the pH value, in order to reach to the requirement for wastewater disposal according to the State Environmental Protection Administration. The level of automation of the pH value control system in China relatively falls behind, research and development of automatic system with good control effects and easy realization has much practical meaning.Because of the characteristics of the acid-base neutralization process in wastewater treatment, such as the inherent strong nonlinearity, delay and uncertainty, pH value is considered as one of the most difficult controlled objects. 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 pH control process theory. Simulation results show that the fuzzy adaptive PID control system for pH value in wastewater treatment has good control effects, which is an ideal intelligent control method.In this thesis, basing on the requests of the control system for pH value in wastewater treatment, a fuzzy adaptive PID controller for pH value is designed, in which the MSP430 as its key part of processor is used. It accomplishes data acquisition of pH value, the fuzzy adaptive PID control algorithm, on-line control and serial communication with the monitor computer. At the same time, the monitor computer can display the field data, and manage the storage of historical records and the monitor of the whole system.The schemes of control system for the pH value in wastewater treatment based on the fuzzy adaptive PID control improve the precision and stability in control process. It is a beneficial attempt to apply advanced control method to solve practical industry problem. The design of the system which has advantages such as reasonable structure, low cost and strong practicability, satisfies the requirements of the automatic control for the pH value in wastewater treatment.