Professor Ong Say Leong is Emeritus Professor at CEE, NUS and he is also Deputy Director at NUS Environmental Research Institute. He has published over 200 technical papers covering topics such as biofilm systems, water/wastewater reclamation and reuse applications, biological wastewater treatment and modelling, membrane technology, emerging contaminants detection and removal as well as computer applications in water and wastewater engineering. Professor Ong is a registered professional engineer and has been involved in consulting jobs on water and wastewater treatment system and water quality management. He is active in the professional circle and is serving in several environmental engineering committees. These includes Governing Board Member of the International Water Association (UK), Member of the Board of Director of the Water Environment Federation (USA), Head of PUB Internal Audit Panel for NEWater and Water Supplies, and Chairman of Singapore Technical Committee on Drinking Water Quality Standards. Professor Ong also serves as Editor/Associate Editor/Editorial Board Member of 10 international journals in the area of water environment. These include an Editor of Water Environment Research (USA); Associate Editor of Water Research (UK); Associate Editor of ASCE Hazardous, Toxic, and Radioactive Waste Management Journal (USA); and Editorial Board Member of the Journal of Water Supply: Research & Technology – AQUA.