USM–IMEC INDUSTRIAL PROJECTS EXPLORE NEW WAYS TO RECYCLE PALM OIL REFINERY WASTEWATER

PENANG, 30 July 2026 - Two final-year students from the School of Chemical Engineering, Universiti Sains Malaysia (USM), have successfully completed industry-sponsored research projects aimed at turning treated palm oil refinery wastewater into cleaner water that could potentially be reuseable.

The Industrial Final Year Projects were sponsored by Integrated Modern Environmental Control Sdn. Bhd. (IMEC). The research was carried out by Aainaa Abdul Razak and Siti Nurafiqah Sharipulazman under the supervision of Professor Dr Ooi Boon Seng, and with industry collaborators Lilian Wong Kim Yoke and Tan Yue Hang from IMEC.

Palm oil refinery wastewater would normally undergo several treatment processes before it is discharged. Although these conventional processes remove most pollutants, small amounts of stubborn organic substances, colour, oil, suspended solids and dissolved salts may still remain. These substances can make the treated water unsuitable for direct reuse.

The two student projects investigated complementary technologies that could provide an additional “final cleaning” step.

Using Electricity to Remove Stubborn Pollutants

In the first project, Aainaa Abdul Razak studied a process known as electro-oxidation. In simple terms, this treatment uses a controlled electrical current to break down pollutants that are difficult to remove through normal biological treatment. The student tested different operating conditions, including the type of salt added to help electricity flow through the water, the acidity of the water, the applied voltage, and the arrangement of the electrodes. Under the best laboratory conditions, the electro-oxidation process removed approximately 98% of the remaining organic pollution, measured as Chemical Oxygen Demand, and 96.7% of the wastewater colour within 40 minutes. The special coated electrode used in the process also remained stable after treatment, indicating that it could potentially be used repeatedly. However, further work is still required to reduce energy consumption and evaluate its long-term performance on a larger scale.

Using Membranes to Produce Cleaner Water

The second project, conducted by Siti Nurafiqah Sharipulazman, investigated the use of membrane filtration to further clean the wastewater. The treatment began with ultrafiltration, which works like a very fine sieve. This step removed approximately 83.3% of the suspended solids and 97.1% of the remaining oil and grease. Removing these materials first also helped to protect the next membrane from becoming blocked. A finer membrane, known as a nanofiltration membrane, was then used to reduce the amount of dissolved salts and other small contaminants in the water. The membrane reduced the salt content by approximately 70.9% to 93.7% under the different conditions tested. When the treatment methods were combined, the resulting water contained lower than detection limit (<2 mg/l) of Chemical Oxygen Demand, indicating that only a very small amount of organic pollution remained. The nanofiltration step removes most dissolved ions in a single pass and can also concentrate the treatment salt into a separate stream so it can be recovered and reused. Based on these laboratory findings, the recovered water has potential for non-drinking industrial uses such as cooling-tower make-up water, process washing and general cooling-water recycling. The membrane system could also retain part of the treatment salt in a concentrated stream, allowing the salt to be potentially reused instead of being discarded.

The results were obtained through laboratory-scale experiments. Further pilot-scale studies will be needed to assess treatment costs, energy use, membrane life, electrode durability and long-term performance before the system can be introduced at an industrial scale. The projects demonstrate how collaboration between universities and industry can provide students with opportunities to solve real industrial problems. Through the Industrial Final Year Project programme, the students gained practical experience working with actual industrial wastewater while contributing ideas that may support more sustainable water management in Malaysia’s palm oil industry.

Text & Photo: Professor Dr. Ooi Boon Seng, School of Chemical Engineering Editing: Mazlan Hanafi Basharudin, Media & Public Relations Centre (MPRC)