Two Pid-Combined Controllers For Dissolved Oxygen Concentration In Wastewater Treatment Process Of A Paper Mill - A Simulation Study

Based on the sequential batch reactor (SBR) simulation model of the wastewater treatment process for a secondary fiber paper mill that we have developed, two control strategies, a neural network (BP-PID controller) and a fuzzy logic system (Fuzzy-PID controller), were separately combined with PID to control the dissolved oxygen (DO) concentration in the SBR process of paper mill. Two cases, without and with the presence of noise, have been studied and evaluated using the criteria considered in BSM1. For the case without noise, both two-control strategies demonstrated better control indices than that of the traditional PID control; for the case with noise, the Fuzzy-PID controller possessed the good control indices at almost the same expense of aeration energy. The results under two cases showed that the Fuzzy-PID controller demonstrated better performance than that of BP-PID controller, in the DO control of SBR process in the paper mill, Fuzzy-PID controller improved the control performance without increasing the aeration energy consumption.