Krist V. Gernaey, Jakob K. Huusom and Rafiqul Gani (Eds.), 12th International Symposium on Process Systems Engineering and 25th European Symposium on Computer Aided Process Engineering. 31 May – 4 June 2015, Copenhagen, Denmark © 2015 Elsevier B.V. All rights reserved. A Comparative study between Neural Networks (NN)-based and Adaptive-PID Controllers for the Optimal Bio-Hydrogen Gas Production in Microbial Electrolysis Cell Reactor M.Y. Azwar a,b , M.A. Hussain b , A.K. Abdul Wahab c and M.F. Zanil d a Chemical Engineering Department, Faculty of Engineering, University of Syiah Kuala, 23111 Banda Aceh, Indonesia b Chemical Engineering Department, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia. c Biomedical Engineering Department, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia. d Chemical and Petroleum Engineering, Faculty of Engineering & Built Environment, UCSI University, 56000 Kuala Lumpur, Malaysia. Abstract The main challenge of the hydrogen production study for the MEC reactor is to obtain a good automatic control system due to the nonlinearity and complexity of the microbial interactions. To address this issue an integrated approach involving process modeling, optimization and advanced control has to be implemented. This work focus on the controller’s performance in the control system; neural network (NN)-based and Adaptive-PID controllers. The study has been carried out under optimal condition for the production of bio-hydrogen gas wherein the controller output are based on the correlation of the optimal current and voltage to the MEC. A Ziegler–Nichols tuning method and an adaptive gain technique have been used to design the PID controller, while the neural network controller has been designed from the inverse response of the MEC neural network model. Keywords: Bio-hydrogen gas, microbial electrolysis cell, neural network-based controller, adaptive-PID controller. 1. Introduction Microbial electrolysis cells (MEC) is part of the microbial electrochemical cell technology which is one of the renewable energy alternatives today. MEC operation is based on the fundamental of a bio-electrochemical process and is a promising renewable energy technology that produce hydrogen gas. Anodophilic microorganisms in the anaerobic MEC bioreactor is capable of oxidizing substrates containing organic materials in the cell compartment into electrical energy. Anodophilic microorganisms is able to break the organic material and wastewater that has been diluted at low concentrations of organic compounds. In the MEC system, due to the addition of voltage into the cathode of the anaerobic-bioreactor, the reaction between protons and electrons occur leading to the formation of hydrogen gas (Rozendal et al., 2006 and Logan, 2010).