Comparative Analysis of pH -Control Algorithms for Water.

Maintaining precise pH levels is critical in water treatment systems to ensure chemical stability, optimize coagulation, and enhance disinfection efficiency. This study conducts a comparative analysis of three pH -control algorithms-proportionalintegralderivative (PID), fuzzy logic (FL), and a hybrid PID-FL approach - in a pilot-scale alkaline water treatment plant. The system was initialized at pH 11 , and FeCl 3 was incrementally dosed until the target pH of 6.5 was achieved. The control algorithms were implemented using an experimental setup consisting of two pH sensors and a peristaltic dosing pump regulated via pulse-width modulation. A Siemens 1215C Programmable Logic Controller and an Atmega 2560 microcontroller managed data acquisition and control execution. Performance evaluation based on autocorrelation analysis indicated that the hybrid PIDFL algorithm exhibited superior performance, achieving faster response times, enhanced stability, and improved disturbance rejection compared to conventional methods. The findings highlight the effectiveness and scalability of hybrid pH -control strategies, particularly in resource-constrained water treatment infrastructures.