Watch This | One trophy, two breakthroughs: HK's sewage surveillance program wins IWA Project Innovation Awards
In August, the 2024 International Water Association (IWA) World Water Congress & Exhibition held in Toronto, Canada welcomed a group of guests from Hong Kong. The Director of Environmental Protection, Dr. Samuel Chui Ho-kwong, together with the Deputy Director of Drainage Services, Mr. Robin Lee Hong-nin, and the Principal MedicalandHealth Officer of the Department of Health, Dr. Kung Kin-hang, led an interdepartmental delegation to attend the event by invitation. Hong Kong's unique Territory-wide Sewage Surveillance Programme won the Gold Award of the 2024 IWA Project Innovation Awards under the category of "Performance Improvement and Operational Solutions.
"This award demonstrates our leading position in sewage surveillance on a global scale," said Dr. Chui. The COVID-19 pandemic once swept across Hong Kong, making it urgent to implement anti-epidemic measures. Identifying more hidden patients without significantly disrupting the daily lives of citizens has become a major challenge for the HKSAR Government.
In brief, sewage surveillance involves collecting samples from sewage manholes, measuring the viral load of the SARS-CoV-2 virus in sewage, and analyzing sewage data for epidemic prevention and prediction. Assistant Director of Drainage Services, Ms. Sussana Lai Wai-kwan, explained that the Drainage Services Department was responsible for providing practical support for sewage sampling and promptly transporting samples to the laboratory for analysis. "Through careful study of the sewage network and field investigations by the Environmental Protection Department and the Drainage Services Department, and the use of geographic information system to locate any hospitals or designated quarantine hotels within the sewersheds, after coupling with epidemiological data, we ultimately selected 154 representative manholes for stationary monitoring. These 154 manholesactually cover 80% of the population in Hong Kong, so that the monitoring data can accurately reflect the geographical distribution of the virus," said Ms. Lai.
From identifying suitable manholes, and spending hours on sewage sampling, to racing against time to transport samples to the laboratory for analysis, every step is by no means easy, requiring continuous cooperation among different government departments. Environmental engineering experts of the Department of Biotechnology, Delft University of Technology of the Netherlands, Professor Mark van Loosdrecht, said, "Hong Kong showed a very good integration of all the different groups which has the capacity, say, university set in using the methods, partly by legislation, partly by having the expertise of the sewage network and the cooperation with Department of Health, so that integrated work of a whole team of people showed that if you work together, you can achieve good things and really change the policies and implementation for that."
Unlike the past when infectious disease surveillance was highly dependent on clinical data, Dr. Chui explained that the sewage surveillance program has achieved two significant breakthroughs. Firstly, by analyzing the viral load of sewage and the locations where the viruses are detected, it identifies hidden carriers in the community to promptly cut-off the transmission chains, thus supplementing the previous limitations of infectious disease surveillance. Secondly, it helps accurately predict the number of patients in Hong Kong for the next 2 to 4 days through the viral load data, with an accuracy as high as 98%. It also helps review the appropriateness of anti-epidemic measures in force and sheds light on the formulation of follow-up actions and directions.
Recalling those challenging times, Dr. Chui remarked, "We had to analyze a large amount of data every day, typically during midnight. And in the next morning, we had to submit the report to the Department of Health to plan for the next rounds of restriction testing. Our entire team could only sleep five to six hours every night." Working through the night was a common occurrence, and facing the unprecedented heavy workload and pressure didn't shake or deter them. Dr. Chui and his team continued to serve the community with dedication and fight the virus on the frontline for several years. In December 2020, the team successfully identified 10 hidden COVID-19 cases in Choi Wan (II) Estate, showcasing the first example in the world to combine sewage surveillance with restricting testing to identify asymptomatic carriers in the community.
The gloom of the COVID-19 epidemic has lifted. According to the Controller, Centre for Health Protection, Department of Health, Dr. Edwin Tsui Lok-kin, Hong Kong has gradually changed from the containment phase at the peak to a mitigation phase. Sewage surveillance is now used by the Department of Health as a means for conducting regular infectious disease surveillance.
Today, sewage surveillance, as a successful example, has brought new inspiration to the world. Director of the National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Professor Yang Min, believes that everyone has realized that sewage surveillance can become a very good supplement to clinical surveillance during this epidemic. The Mainland and many countries around the world are exploring ways to accumulate experiences in sewage surveillance, with a view to building a new anti-epidemic system against viruses in the future.
Holding the trophy that represents every bit of his efforts, the multi-award-winning Dr. Chui smiled from his heart and shared his ambition to pass on his experience, "In 2023, I attended an international IWA conference to give a keynote speech. Many of the participants stood up and applauded after my speech, saying that Hong Kong had made a great breakthrough, which is not only applicable to COVID-19 but also to future epidemics that can be applied worldwide," said Dr. Chui.
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HK's sewage surveillance programme wins IWA Project Innovation Awards
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