PH Control In Wastewater Treatment And Development Of The Supervisory System

With the continuous increase of demands for the petroleum and gas, there are a lot of developments of the petroleum and gas in our country. As the exploration for the petroleum is increasing, the pollution to the environment becomes more serious. How to solve the problem of wastewater treatment has become an important subject in the world.This paper bases on wastewater treatment field in Liao He oil field, researches of the pH control problem in wastewater treatment, makes the solution which flowing in and out estimated as the course parameter and state parameter. It estimates the ion of the solution and the constant of the weak acid, gets the exact model, controls the process of the reaction, and makes the pH value of outlet wastewater to be the expected value. When the small perturbation has appeared in the system, it can still guarantee to the stability of pH value in the outlet wastewater. The result of emulation experiment indicates that the backstepping method can control the nonlinear system with unknown parameters effectively, it can follow the change of the ion of pH system through regulate the parameters of the controller, and reaches to the standard in short time with little error, it can control the system online and identify the unknown parameters in real time.Distributed control system which is made up of field control unit is used in waste water treatment field, the software is developed based on Windows 2000, has abundant functions, such as alarm, remote control, data processing, automatic report, history trend display, statistics etc. and designs the program of PLC, installs the equipments in the field. Because of the reasonable structure, perfect functions, high reliability, this system meets to the automatic manufacture in wastewater treatment field. It starts to work in the end of 2004, now it works steadily and well.