Ir Prof. Dan Tsang is a Professor in the Department of Civil and Environmental Engineering at the Hong Kong University of Science and Technology and Pao Yue-Kong Chair Professor in the State Key Laboratory of Clean Energy Utilisation at Zhejiang University in China. Dan was a Professor and MSc Programme Leader at the Hong Kong Polytechnic University, Visiting Professor at the University of Queensland in Australia and Chulalongkorn University in Thailand, Visiting Scholar at Stanford University in the US and IMETE Scholar at Ghent University in Belgium, and postdoctoral fellow at Imperial College London in the UK. He has more than 20 years of R&D experience, published more than 500 articles in top 10% journals, and was selected as Stanford University's Top 2% Scientists and Clarivate's Highly Cited Researchers in 2020-2022. Dan’s team aspires to develop green technologies for long-term decarbonisation and promote resources circularity and sustainable development.

Enhancing Water Resilience with Blue-Green Infrastructure in New Development Areas: A Pilot-scale Study on Bioretention Systems for Stormwater Harvesting

Daniel C.W. Tsang ^a,b,*, Jittrera Buates ^b, Zibo Xu ^b, and Mingjing He ^b

^a Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
^b Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
*Corresponding author: dan.tsang@polyu.edu.hk; cedan@ust.hk

Abstract:

Sustainable drainage system (SuDS) is an ecosystem-based design that can safeguard water security and resilience for sustainable development. During stormwater treatment by SuDS, engineering the filter media is the key to the reliability for high pollutant removal, efficient nutrient immobilisation, and sustainable vegetation growth. Biochar can be a promising material as the amendment for SuDS. In this study, we assess the efficiency of biochar and compost integration in a pilot-scale SuDS (combined bioswale and bioretention basins) for treating simulated stormwater under different rainfall scenarios. The co-application of wood waste biochar and food waste compost could delay the overflows and afford better stormwater infiltration efficiency than the control and their sole application. An impressive removal rate of 80% and above for all types of commonly encountered metals/metalloids was achieved. Trace organic contaminants, including diuron, ATZ, and 2,4-D, could also be immobilised to varying extent by the co-application of biochar and compost. In the meantime, over 70% of phosphate could be retained or immobilised due to the enhanced phosphate uptake by plants. Moreover, the higher activities of β-D-cellobiosidase and urease enzymes were detected in the SuDS, indicating healthier soil conditions and sustainable vegetation growth. These advantages make SuDS incorporating biochar and compost a promising design for effective stormwater management in the New Development Areas, fostering the establishment of Sponge City and Blue-Green Infrastructure in Hong Kong.