CHEMICAL ENGINEERING TRANSACTIONS VOL. 63, 2018 A publication of The Italian Association of Chemical Engineering Online at www.aidic.it/cet Guest Editors: Jeng Shiun Lim, Wai Shin Ho, Jiří J. Klemeš Copyright © 2018, AIDIC Servizi S.r.l. I SBN 978-88-95608-61-7; I SSN 2283-9216 Optimisation of Wastewater Volume of Single Chamber Biological Cathodic Protection System Wan Nor Azita W Ali a , Anis Fitri Afira Azman a , Mohd Dinie Muhaimin Samsudin a,b, *, Muaz Mohd Zaini Makhtar c , Norazana Ibrahim a , Rafiziana Md Kasmani a a Department of Energy Engineering, Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia b UTM-MPRC Institute for Oil and Gas, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia c School of Chemical Engineering, Universiti Sains Malaysia, 14300, Nibong Tebal, Pulau Pinang, Malaysia dinie@utm.my In this study, the concept of Microbial Fuel Cells (MFCs) was applied in the biological cathodic protection (CP) system in order to protect steel pipe. There are various factors affect the performance of the system including the volume of the medium.The purposes of this study were to analyse and optimise the effect of volume ratio of wastewater to the sand on biological CP performance by using Taguchi method. The maximum performance of biological CP in this study was obtained at the largest volume ratio. The orthogonal array and the signal-to-noise ratio (S/N) were employed to study the effect of volume ratio on performance of biological CP. The CP potential vs. copper sulfate electrode (CSE) was -835 mV. It shows that the corrosion of carbon steel pipe was reduced since the native potential of the carbon steel pipe vs. CSE was -531 mV. 1. Introduction Oil and gas pipelines have been used widely as transportation network in transferring oil and gas. Primary mechanism resulting in oil and gas pipelines failures has been identified as corrosion. Pipeline corrosion is a complex phenomenon where it is resulted from the interaction of multiple reactions and processes occurring simultaneously among material and the environmental interaction (Norsworthy, 2014). Disrupting in the transport process will occur due to damage induced by pipeline corrosion. This problem will increase the direct cost and lead to unfavourable events, such as fires and explosions. For these reasons, cathodic protection (CP) system has been introduced as an alternative of corrosion prevention for underground structures such as oil/gas pipelines (Kuang and Cheng, 2015). According to International standard ISO 8044, CP is defined as decreasing corrosion potential by electrochemical protection to a level at which the corrosion rate of the metal is significantly reduced. Impressed current cathodic protection (ICCP) is one of the methods used in CP system. In ICCP method, the use of an external supply which is rectifier is introduced to convert alternating current (AC) to direct current (DC) in order to provide the cathodic polarisation of the structure (Ranade et al., 2016). ICCP is more convenient method and popular than sacrificial anode because it provides remarkable protection against corrosion in all types of ships and offshore platforms, pipelines, ports and others. Since the uses of ICCP system will be limited due to the depletion of the fossil fuels to generate electricity in the future, the biological CP system has been introduced as an alternative solution (Cheng, 2015). In Microbial Fuel Cell (MFC), the electrons generated by the bacteria, which is consuming substrate were used in cathodic reaction. The electrons transfer to the cathode by using external path. The potential of the metal in this system can be shifted to the negative direction as in ICCP due to the capability of electrogenic microorganisms to produce protons and electrons from substances under anaerobic condition (Wang et al., 2016). The potential differences between the electron acceptor and respiratory system in biological CP generates requirement current density and voltage to make electricity. In this study, the concept of a single DOI: 10.3303/CET1863070 Please cite this article as: Wan Nor Azita W Ali, Anis Fitri Afira Azman, Mohd Dinie Muhaimin Samsudin, Muaz Mohd Zaini Makhtar, Norazana Ibrahim, Rafiziana Md Kasmani, 2018, Optimisation of wastewater volume of single chamber biological cathodic protection system, Chemical Engineering Transactions, 63, 415-420 DOI:10.3303/CET1863070 415