Development of Fuzzy Logic pH controller for pH Neutralization in Waste Water Treatment Plant (WWTP)

pH neutralization is one of the important processes in Wastewater Treatment
Plant (WWTP). As WWTP used to treat eftluent and discharged water to public sewage,
the right pH is important to save the enviromnent, safety, fulfill the rules and regulations
and keep the plant equipment in safe condition. pH neutralization is well known fur
highly non-linear characteristic with high sensitivity at the neutral region. Thus, pH
neutralization is of the hardest parameter to be controlled in WWTP. From the literature
review, current and most popular control strategy like PI controller produces certain
range of errors. This is due to PI controller unable to compensate the non-linear
characteristic of pH neutralization process. Advanced control strategy is believed to be
the solution to control pH neutralization process in WWTP. Therefore, the objective of
this project is to investigate and design advanced control strategy. A mathematical
modeling is used to develop a plant model based on McAvoy Model. The plant model is
obtained from previous researcher. From the validation of the mode~ the plant is
accepted to be used throughout the project. Both conventional and advanced control
strategy is developed. The development of controller is carried out in SIMULINK
enviromnent. Evaluation of the controller performance is based on few parameters such
as settling time, rise time and integral of absolute error. Based on the simulation results,
Fuzzy Logic has given a excellent control performance compared to PI controller. Fuzzy
logic is able to compensate any changes in high sensitivity in neutral region. In
conclusion, advanced control strategy of Fuzzy Logic able to deal with high nonlinearity
of pH neutralization process compared to conventional control strategy which is
PI controller. The findings in this project will encourage other researcher to implement it
fur other non-linear processes and being implemented in real time industry.