A passive sampling system engineered by an international research team has been demonstrated to detect SARS-CoV-2, the virus responsible for COVID-19, in wastewater at three different scales — an individual lot, suburb and city.

Wastewater sampling has emerged as a useful tool to locate, track and trace evidence of SARS-CoV-2 in residential communities. COVID-19-infected individuals will generally shed or excrete the SARS-CoV-2 virus through human waste or via coughing or sneezing. These excretions end up in wastewater drains when people flush their toilets or have a shower. Wastewater monitoring for such viral evidence can help with targeted health care programs and other actions intended to curb the spread of this virus.

Collaborators from Australia and the Netherlands assembled the device, dubbed the Torpedo Passive Sampler, using cotton buds, medical gauze swabs and lab grade electronegative membranes, all encased in The inexpensive Torpedo Passive Sampler is an accurate and simple testing device to detect SARS-CoV-2 in wastewater. Source: Monash UniversityThe inexpensive Torpedo Passive Sampler is an accurate and simple testing device to detect SARS-CoV-2 in wastewater. Source: Monash Universitya narrow 3D printed shell. Different designs were developed and tested, and each was equipped with a metal weight to keep the sampler submerged.

The inexpensive passive samplers were placed across eight study sites in Victoria, Australia, including systems that collected the wastewater of 260 residents and staff near an aged care facility and Melbourne’s largest sewage treatment plant serving more than two million people. All study sites had known cases of COVID-19 during the second wave of infections.

The field study proved successful in detecting SARS-CoV-2 using passive sampling. A statistically significant positive relationship between the concentrations of SARS-CoV-2 in wastewater and the levels found on the passive samplers was observed.

The intellectual property for the Torpedo Passive Sampler is open source and 3D printing files are able to be shared for immediate use.

Australian researchers from Monash University, Melbourne Water Corporation, The Walter and Eliza Hall Institute of Medical Research, University of Melbourne, South East Water, Royal Melbourne Hospital, LS Hydrographics and Barwon Water contributed to this development, as did participants from TU Delft and Partners4UrbanWater, the Netherlands.

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