Speakers

Biography: Prof. Ng Choon Aun currently serves as a Professor in the Department of Environmental Engineering and has held the position of Dean at the Faculty of Engineering and Green Technology since 2022. He earned his PhD in Environmental Engineering from Nanyang Technological University, Singapore, and holds a Master of Engineering in Civil–Environmental Management as well as a Bachelor of Engineering (Hons) in Civil–Environmental, both from Universiti Teknologi Malaysia. Prof. Ng’s research expertise lies in the areas of wastewater treatment, specifically using aerobic and anaerobic activated sludge processes, hybrid membrane technologies, and the development of sustainable green building materials. Over the course of his career, he has been involved in more than 30 research projects and has published over 70 peer-reviewed journal articles and 30 conference papers. He is the principal inventor of two granted patents involving membrane technology and wastewater treatment systems, and he recently filed another patent application in the field of green construction materials. Beyond academia, Prof. Ng is actively engaged as a consultant and professional trainer for numerous commercial and industrial projects. He is a Fellow of the ASEAN Academy of Engineering and Technology (AAET), a registered Professional Engineer with the Board of Engineers Malaysia (BEM), and also serves as a panel member for the accreditation of engineering programmes under BEM.

Abstract: The talk explored the innovative use of various waste-derived materials—specifically calcined alum sludge, partially carbonized alum sludge ash (ASA), ground granulated blast furnace slag (GGBFS), and bottom ash—as partial replacements for cement and sand in mortar production. The findings demonstrated that calcined alum sludge, particularly when treated at 800 °C, resulted in the highest mortar strength among all tested conditions. However, increasing the replacement level beyond 5 % led to a decline in workability, compressive and flexural strength, and overall durability. This was primarily due to the increased water demand and higher porosity caused by the sludge’s properties. In the second study, ASA treated at 200–300 °C was combined with GGBFS to assess their effectiveness as supplementary cementitious materials. While higher ASA content adversely affected mechanical strength and workability, an optimal blend of 2.0 wt% ASA and 4.0 wt% GGBFS achieved favorable performance, including a compressive strength of 20.6 MPa after 28 days, and contributed significantly to waste minimization efforts. The third study focused on bottom ash derived from thermal plasma-treated municipal waste. When used to replace 5–15 % of cement, it reduced strength and workability; however, substituting 10–20 % of sand with unwashed bottom ash led to improved strength and reduced porosity and water absorption. Collectively, these studies underscore the promising potential of incorporating industrial and municipal waste materials in mortar mixtures to support sustainability and environmental conservation. Nevertheless, careful control and optimization of replacement levels are essential to ensure the mechanical and durability properties of the final product are not compromised.