Professor Huang Xia’s team at the School of Environment, Tsinghua University has made new progress in the research of SARS-CoV-2 in sewage. In addition to the detection and monitoring work in sewage in the early stage of COVID-19, they also regulated the operation procedure of centrifuge ultrafiltration concentration method and did the compiling work of Method Standard for Enrichment and Nucleic Acid Detection of SARS-CoV-2 in Sewage.
Since the outbreak of COVID-19, there have been more than 600 million of confirmed cases, including 6 million deaths. In addition to the transmission through droplets and contact, SARS-CoV-2 can also enter the drainage system through excreta. The occurrence of SARS-CoV-2 in the drainage system and its early warning and prediction of the pandemic situation based on the detection of nucleic acid fragment of SARS-CoV-2 in sewage have always been a hot topic. Since the outbreak of COVID-19 in March 2020, Prof. Huang Xia’s team has started the research on the detection and occurrence of SARS-CoV-2 in sewage. They conducted SARS-CoV-2 detection and monitoring of sewage in the drainage system in Wuhan and Beijing during the epidemic outbreak. Related research results have been published in the Journal of Hazardous Materials and the official journal of the Chinese Academy of Engineering Engineering .
Schematic of the detection method of SARS-CoV-2 nucleic acid fragment in sewage system
In order to study the distribution of SARS-CoV-2 in sewage, the research team has developed the method of SARS-CoV-2 enrichment and nucleic acid detection in sewage at the beginning of the COVID-19. Results have found that there is a relatively high correlation between the viral load in sewage and the number of reported clinically infected cases, which indicates that SARS-CoV-2 detection of sewage is an effective monitoring method of the early warning and prediction of the pandemic development. The team further studied the attenuation law of SARS-CoV-2 in sewage under different environmental conditions. The results show that the virus attenuation in sewage is highly temperature-dependent.
Detection of Covid-19 nucleic acid fragments in sewage systems before and after small-scale pandemic(Left picture: municipal sewage treatment plant, right picture: sewage pipe network, Day 0 refers to the end time of small-scale pandemic)
Based on the existing research work, Prof. Huang Xia’s team, together with the Research Center for Eco-Environmental Sciences and Chinese Academy of Sciences and the National Institute for Viral Disease Control and Prevention (China CDC), jointly completed the compilation of the Method Standard for Enrichment and Nucleic Acid Detection of SARS-CoV-2 in Sewage. The standard specifies the specific operating procedures for three enrichment methods of SARS-CoV-2 in sewage, including PEG precipitation, aluminum salt flocculation and centrifugal ultrafiltration, as well as nucleic acid extraction and detection methods. Prof. Huang Xia’s team was mainly responsible for the compilation of centrifuge ultrafiltration concentration method, which clarified the aperture of ultrafiltration cup and centrifugal force in this method, and standardized the operation procedures of this method. The Standard was issued and implemented on 24 March 2022, providing the basis and guidance for SARS-CoV-2 detection in sewage in China.
The release notice of the Method Standard for Enrichment and Nucleic Acid Detection of SARS-CoV-2 in Sewage
This research work is funded by the Major Program of the National Natural Science Foundation of China and special projects of the Chinese Academy of Engineering. Prof. Huang Xia from the School of Environment of Tsinghua University is in charge of this work, and Associate Prof. Liu Yanchen and Associate Prof. Zhou Xiaohong from the School of Environment are the main participants of relevant work. Yang Shaolin, PhD student of the School of Environment, and Dong Qian, postdoctoral fellow of the School of Environment, are the main participants in the establishment of the detection method and the on-site detection of SARS-CoV-2 in sewage.
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