Membrane and Water Treatment, Vol. 11, No. 2 (2020) 97-109 DOI: https://doi.org/10.12989/mwt.2020.11.2.097 97 Copyright © 2020 Techno-Press, Ltd. http://www.techno-press.org/?journal=mwt&subpage=7 ISSN: 2005-8624 (Print), 2092-7037 (Online) 1. Introduction The increase of palm oil demand in recent years has contributed to the rapid development of palm oil industry in Malaysia. This has directly resulted in an increase of waste produced during the palm oil processing. One of the major wastes produced from palm oil processing is palm oil mill effluent (POME), the largest source of industry wastewater in Malaysia. It is estimated that Malaysia produces around 53 million tons of POME annually (Pogaku et al. 2015). POME is a colloidal suspension that contains 95%–96% water, 0.6%–0.7% oil, and 4%–5% solid. Direct discharge of POME into the water body without proper treatment could impose serious environmental problems to the ecosystem, such as the change of soil properties, air pollution, water pollution, and greenhouse gas emission, all of which attribute to the high biological oxygen demand (BOD), chemical oxygen demand (COD), oil and grease, total solids, and noxious smell (Khatun et al. 2017). Corresponding author, Senior Lecturer E-mail: yh_teow@ukm.edu.my The commonly used commercial methods for POME treatment in Malaysia integrate anaerobic and aerobic ponding systems. However, the integrated anaerobic and aerobic ponding systems require large land area and long retention time (around 20 to 200 days), which is the main drawback of this POME treatment method (Zhang et al. 2008). Besides that, the treated POME through integrated anaerobic and aerobic ponding systems is unable to meet the industry’s wastewater discharge standards set by relevant authority. As such, many studies have been carried out by researchers to discover alternative and efficient POME treatment method, including adsorption (Mohammed et al. 2014), photocatalytic process (Alhaji et al. 2016), biofilm reactor (Abu Bakar et al. 2018), microalgae treatment (Takriff et al. 2016), and membrane filtration (Ho et al. 2018). Among the aforementioned treatment methods, membrane filtration showed the most significant performance in POME treatment, with several advantages of the membrane technology, such as small footprint, consistent effluent quality, less chemical usage, as well as easy maintenance and operation .A pilot-scale integrated system that combined the sand filter and activated carbon filter as pretreatment, coupled with Thermo-responsive antifouling study of commercial PolyCera® membranes for POME treatment Teow Yeit Haan 1,2 , Loh Wei Chean 2 and Abdul Wahab Mohammad 1,2 1 Research Centre for Sustainable Process Technology (CESPRO), Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia 2 Department of Chemical and Process Engineering , Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia (Received April 1, 2019, Revised November 29, 2019, Accepted December 20, 2019) Abstract. Membrane fouling is the main drawback of membrane technology. Frequent membrane cleaning and membrane replacement are, therefore, required to reduce membrane fouling that causes permeate flux reduction, lower rejection, or higher operating pressure. Studies have proved that the alteration of membrane properties is the key controlling factor in lessening membrane fouling. Among stimuli-responsive membranes, thermo-responsive membrane is the most popular, with a drastic phase transition and swelling-shrinking behavior caused by the temperature change. In this study, the thermo-responsive ability of two commercial membranes, PolyCera® Titan membrane and PolyCera® Hydro membrane, at different temperatures was studied on the antifouling function of the membrane in palm oil mill effluent (POME) treatment. The evaluation of the membrane’s thermo- responsive ability was done through three cycles of adsorption (fouling) and desorption (defouling) processes in a membrane filtration process. The experimental result depicted that PolyCera® Hydro membrane had a higher membrane permeability of 67.869 L/m 2 .h.bar than PolyCera® Titan membrane at 46.011 L/m 2 .h.bar. However, the high membrane permeability of PolyCera® Hydro membrane was compensated with low removal efficiency. PolyCera® Titan membrane with a smaller mean pore size had better rejection performance than PolyCera® Hydro membrane for all tested parameters. On the other hand, PolyCera® Titan membrane had a better hydrodynamic cleaning efficiency than PolyCera® Hydro membrane regardless of the hydrodynamic cleaning temperature. The best hydrodynamic cleaning performed by PolyCera® Titan membrane was at 35°C with the flux recovery ratio (FRR) of 99.17 ± 1.43%. The excellent thermo-responsive properties of the PolyCera® Titan membrane could eventually reduce the frequency of membrane replacement and lessen the use of chemicals for membrane cleaning. This outstanding exploration helps to provide a solution to the chemical industry and membrane technology bottleneck, which is the membrane fouling, thus reducing the operating cost incurred by the membrane fouling . Keywords: fouling; thermo-responsive; PolyCera® membrane; antifouling; POME treatment