Endocrine-disrupting chemicals (EDCs), pharmaceuticals and personal care products (PPCPs) are extensively used in industrial and consumer applications. They are widely recognised as typical contaminants of emerging concern because of their environmentally persistent and bio-accumulative properties. Even in very low concentrations, they can disturb our hormonal balance, leading to reproductive impairment, abnormal development and growth retardation. Water and wastewater treatment systems worldwide face the challenge of effectively removing these contaminants. 

Research by Dr Chris Tsang Yiu-fai, Associate Professor at the Department of Science and Environmental Studies, The Education University of Hong Kong, and his collaborators has furthered understanding of novel solutions for EDCs and PPCPs, and their removal mechanisms in the biological treatment processes. He has developed a novel approach to adapting existing systems using mixed culture and waste-derived materials. This has been piloted in mainland China since 2016, benefiting around 200,000 people. 

Dr Tsang and his fellow researchers from South China University of Technology and the University of Strathclyde have investigated the occurrence, fate and removal mechanisms of EDCs and PPCPs in biological wastewater treatment plants (WWTPs) in Hong Kong, the mainland and Scotland. They have detected 18 antibiotics in WWTPs and receiving waters in Guizhou, EDCs and PPCPs in biologically treated effluent discharged from two WWTPs in Glasgow, and five PPCPs in two major WWTPs in Hong Kong. 

The findings provide a theoretical and practical basis to design, develop and optimise new processes for stable and efficient EDC and PPCP removal in water purification and wastewater treatment. Through laboratory- and pilot-scale studies, Dr Tsang has developed a novel solution integrating micro-organisms and biowaste-derived materials in bioreactors that improve the efficiency of EDC and PPCP biodegradation in WWTPs. His work has also contributed to industry understanding of such practice after being shared with a wide range of policymakers and water engineers both locally and internationally, thus improving drinking water quality and community health.  

Dr Tsang has also led closely connected research on resources recovery – the retrieval of value-added products, such as engineered biochar and biogenic flocs, for environmental remediation from waste sludge, a secondary pollutant in the wastewater treatment processes. Hong Kong’s Water Supplies Department has invited him to conduct a pilot project to turn sludge into eco-construction materials. 

Dr Tsang's work has been published in more than 175 journal articles. His research on wastewater management, drinking water treatment, and water conservation has been turned into teaching resources used by more than 370 primary schools, contributing to STEM education. 

He has also shared his expertise as an advisory committee member to the Environmental Association and as Wastewater Treatment Plant Technical Consultant to the Hong Kong Federation of Youth Groups. 

For the full article of the impact case study, please click here.