A critical component in the fight against COVID-19 is establishing where transmission of the virus occurs. Since the start of the pandemic in early 2020, the public naming of exposure sites by health authorities, and the requirement for people who were at the same sites during the same time to monitor for symptoms or get tested themselves has been an ongoing part of the public health response. Wastewater testing has been another crucial way Governments and health departments can identify where COVID-19 may be present in the community to help to stop the spread. That’s why used water from toilets, sinks, bathrooms and dishwashers is being analysed and tested for fragments of SARS-CoV-2, the virus that causes COVID-19. Fragments of the virus can enter the wastewater system through people who have, or have recently had, COVID-19. People shed the virus through used tissues, off their hands
and skin or in stools, and this shedding can continue for weeks after a person is infectious. “The COVID-19 virus, SARS-Cov-2, can enter wastewater infrastructure through any of those means, however, is likely to enter wastewater principally from faecal and respiratory shedding. Shed virus is then detected by analysing the wastewater using analytical methods that are specific for SARS-CoV-2,” says Dr Nick Crosbie, Recycled Water and IWM Research Manager at Melbourne Water. “Wastewater monitoring is equivalent to obtaining and analysing a large community-based composite sample of faeces, saliva, vomit, sputum, urine, shed skin and other material shed during personal cleansing, washing, bathing, and excreting.” In Victoria, wastewater samples are taken from more than 120 sites including the large Melbourne Eastern and Western wastewater treatment plants, regional wastewater treatment plants and more than 70 locations throughout the metropolitan sewerage system.
Dr Crosbie describes the Department of Health’s surveillance as dynamic, “meaning that it is adjusted to meet changing needs, for example to facilitate surge testing during outbreaks. “Samples are obtained by Australian Laboratory Services by ‘grab sampling’, auto-sampling, and by the deployment of so-called ‘passive samplers’ which accumulate the SARS-CoV-2 virus in the period of their deployment. In total, between a few 100 to more than 1,000 samples are collected and processed in a seven-day period. “The samples are analysed by Australian Laboratory Services, with Monash University undertaking analysis of the passive samplers. Presumptive detections are confirmed by analysis performed at the Walter and Eliza Hall Institute of Medical Research.” While wastewater testing has been of public prominence during the pandemic, it is regularly undertaken around the world to monitor poliovirus, norovirus and adenovirus. Dr Crosbie has been personally involved in the work for about five years.
Know what’s Information is critical in the fight against COVID-19 and wastewater is one of the key sources used to identify the presence of the virus in our communities.
10 | Australian Plumbing Industry Magazine | Spring 2021
