Prof Tong ZHANG

The University of Hong Kong

Prof Tong Zhang is a Chair Professor of Environmental Engineering in Environmental Microbiome Engineering and Biotechnology Laboratory, Department of Civil Engineering, at The University of Hong Kong (HKU). His researches include environmental microbiome engineering and biotechnology, environmental bioinformatics, anaerobic digestion and bioenergy from wastes/wastewater, biological wastewater treatment (N removal and P recovery), biodegradation of emerging pollutants (antibiotics, PPCP and EDCs), antibiotic and antibiotic resistance genes, etc.  He has published 280 peer-reviewed papers on the above topics, and has more than 27, 000 citations (Google Scholar). He is a senior editor of Microbiome, and an associate editor of Applied Microbiology and Biotechnology. He got First-Class Award in Natural Science (China Ministry of Education) in 2015, Second-Class Award State Natural Science Award (China State Council) in 2016, Outstanding Research Student Supervisor Award of HKU in 2017, and Outstanding Research Award of HKU in 2020. He has been listed as “Highly Cited Researcher” by Clarivate in 2018 (Cross Field), 2019 (Environment and Ecology), 2020 and 2021 (Environment and Ecology; Microbiology).


Surveillance of COVID-19 Virus in Sewage

Sewage surveillance, which tests the collection of faecal samples in a given sewershed, could offer a supplementary strategy for measuring population-level infections. With the strong support from different bureaus/departments of Hong Kong government, the research team tested SARS-CoV-2 virus in community sewage collected from various sites of Hong Kong using methods established by the HKU team, to provide early-warning signals for the re-emergence of COVID-19 in local communities as a supplementary part for the clinical tests.

Sewage testing method for SARS-CoV-2 includes the following steps: inactivation, virus concentration, viral genetic material (RNA) extraction and quantification via reverse transcription qPCR. By testing sewage samples collected from 26 stationary sites in Hong Kong, the sewage surveillance had effectively caught the rising trend of clinical cases in the 4th wave starting from the middle of November 2020. Sewage testing results also provided a basis for statutory public health action in identifying buildings and places for compulsory testing to uncover the infected individuals in local community. From 28 December 2020 to 9 February 2021, sewage surveillance-initiated compulsory testing had identified more than 50 confirmed cases, cutting off hidden transmission chains in these communities. Our results about sewage surveillance for SARS-CoV-2 in Hong Kong have demonstrated that the sewage surveillance could be used for the following purposes: (1) Providing early warning signals for COVID-19 outbreak; (2) Tracking the development trend of community outbreak; and (3) Complementing the monitoring of estates with infection clusters. Since December 2020, daily sewage testing results have been incorporated into local monitoring scheme as an essential part of the whole control strategy of COVID-19. The systematic routine sewage monitoring programme established by Hong Kong government now covers over 112 stationary sampling sites, providing early warning signal of COVID-19 re-emergence for over 5.4 million people.