Prototype Aeration System for Dissolved Oxygen Control Using a Paddle Wheel Mechanism

Control methods of dissolved oxygen (DO) in water may involve nonlinearities, non-Gaussian noise, external disturbances, and unknown dead times, which makes its study particularly compelling. Nevertheless, requirements such as extensive infrastructure and expensive instrumentation represent significant limitations for experimentation within a typical control laboratory. Therefore, this paper presents an easy-toreplicate aeration process for DO control experimentation. The proposed approach employs a cascade strategy that combines Fuzzy Logic Control and Sliding Mode Control to regulate DO levels and paddle wheel speed, respectively. The system features a reconfigurable paddle wheel aerator engineered for experimental evaluation. Moreover, the setup incorporates a DC motor with an encoder, a DO sensor, and a standard computer. For validation purposes, a small water tray was used, in which sodium sulfite was added to reduce the DO level, followed by activation of the paddle wheel to increase it. Finally, simulated and experimental results are presented to validate the proposed system.