A simple, cost-effective and portable device, shaped like a torpedo, has been successful in detecting SARS-CoV-2 in wastewater in Victoria – opening avenues for a global rollout as the virus continues to ravage major cities.
Researchers at Monash University's Department of Civil Engineering, in partnership with a consortium of universities and industry locally and internationally, have provided the first evidence that passive samplers can be used to detect SARS-CoV-2 in wastewater at three different scales – an individual lot, suburb and city.
Dubbed the 'Torpedo Passive Sampler' and the 'sewage submarine', it was constructed using cotton buds, medical gauze swabs and lab grade electronegative membranes. They were encased in a narrow 3D printed shell.
The passive samplers were placed across eight study sites in Victoria ranging from systems that collected the wastewater of 260 residents and staff near an aged care facility, to Melbourne's largest sewage treatment plant that pools wastewater from more than two million residents.
Seven of the eight sites were in metropolitan Melbourne, with the other in Colac. All sites were chosen due to having known cases of COVID-19 during the second wave of infections.
Analysis showed success in detecting SARS-CoV-2 using passive sampling. The research also demonstrated that when the daily average SARS-CoV-2 concentration in wastewater exceeds 1 copy per mL, at least one of the passive samplers deployed at the same site on the same day was also positive.
In great news for Australian state and territory governments, and countries across the world, the intellectual property for the 'Torpedo Passive Sampler' is open and 3D printing files are able to be shared for immediate use.
In just five months, more than 2500 'Torpedo Passive Samplers' have been exported and used in all states and territories of Australia, New Zealand, Canada, the Netherlands, and are soon to arrive in the USA and Indonesia.
Passive sampling involves the deployment of a device in a waterbody for a known time, allowing for pollutants in the water to interact with the device.
Lead author, Associate Professor David McCarthy, from Monash University said passive sampling presents a cheap, safe and easy alternative to traditional wastewater sampling.
"These results indicate that cotton buds, electronegative membranes and gauzes can be used as passive samplers of SARS-CoV-2 in human wastewater. This is the first proof of concept that one or more of these passive samplers could be prime candidates
