Cascade Control of the PH in an Anaerobic Wastewater Treatment System

For an anaerobic treatment system, pH is an important environmental factor that can influence the activity of anaerobic bacteria. Especially in the final anaerobic process stage, the methane bacteria need the optimal pH range from 6.8 to 7.2. The control of PH is a difficult link in the anaerobic treatment system due to its nonlinearity and large time-delay. Aiming at the difficult point in the pH control of the anaerobic wastewater treatment system, a mathematical model of PH control is established in the essay. On this basis, a traditional PID control and a cascade control are adopted to carry out simulation and comparison with MATLAB. The results show that: the cascade control has better comprehensive effect in terms of response speed, stability and disturbance resistance.