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Covid-19 Wastewater Testing in the NT
COVID-19 WASTEWATER TESTING IN THE NT. HOW IT WORKS AND WHY IT’S IMPORTANT
By Lauren Roberts Posted Sunday 15 Aug 2021 at 4:50pm
When Tony Boland collects samples of wastewater for coronavirus testing in Darwin’s northern suburbs, he needs to keep one eye peeled for crocodiles.
Mr Boland, managing director of Trop Water, said the sewage ponds in Leanyer was home to at least one saltie.
To minimise risk, Mr Boland said two people visited the site together so one can be the “spotter”.
“There’s always crocodiles here,” he said.
“You basically need to show respect for an apex predator in its natural environment.”
But mosquitos and the waste itself were more dangerous than a well-fed crocodile, Mr Boland said.
“Crocodiles, while they’re front and centre of people’s minds, they’re not the highest risks in these types of environments,” Mr Boland said.
“The biggest risk we face here is actually the wastewater itself, nothing holds human borne pathogens better than humans.”
The NT’s wastewater program
The NT started testing its wastewater for traces of SARSCoV-2 (the virus which causes COVID-19 disease) in May this year. It was the last jurisdiction in Australia to launch its own COVID-19 wastewater testing program.
NT Deputy Chief Health Officer Charles Pain said experts were trialling the system for months before the launch.
“Because we didn’t have community spread in the Territory, we didn’t have to rush into it,” he said.
“We were able to take our time.”
According to NT Health, there are now 10 catchment sites in the Greater Darwin area and four in Alice Springs.
The Howard Springs site
The sewage ponds are known to be home to at least one saltwater crocodile (ABC News: Lauren Roberts)
Mr Boland says the crocs in the Leanyer ponds are well-fed and rarely bother his team (ABC News: Hamish Harty)
NT Health says Leanyer is one of 10 catchment sites in Greater Darwin (ABC News: Hamish Harty)
exclusively receives wastewater from the quarantine facility.
How exactly does it work?
Mr Boland and his team test the raw sewage that comes into the ponds.
Positive results act as an early warning system, telling health authorities someone may have been in the community with COVID-19.
To test the wastewater, Mr Boland’s crew put a 3D printed “shuttle” into the debris.
Inside the shuttle, Mr Boland explains, is a negatively charged membrane that attracts coronavirus RNA.
The shuttle usually collects information for between three and four days.
During COVID-19 outbreaks (such as the recent Tanami cluster), it collected data over just 24 hours, allowing more frequent testing.
When the time’s up, Mr Boland’s team pulls up the shuttle, bags it and refrigerates it before sending the sample off to South Australia for scientific testing.
The SA laboratory looks for certain markers which are unique to SARS-CoV-2 (the virus which causes COVID-19 disease) and reports what they find out to health authorities.
Test results are returned in about 24 hours, Mr Boland explained, although it was quicker during the Tanami outbreak.
Wait, why send it to SA?
Dr Pain said because the testing was very specialist, there wasn’t currently a team who could do it locally.
However, through a program called the Collaboration on Sewage Surveillance of SARSCoV-2 (ColoSSoS Project), Dr Pain said the NT was able to call on interstate scientists.
“It’s much better for us to be part
The shuttle used to test wastewater for coronavirus in the NT is 3D printed (ABC News: Lauren Roberts)
of that partnership than try and do it ourselves,” he said.
And Dr Pain said the NT was not looking at doing this laboratory testing locally.
“At the moment, we are very happy with the way things are working,” he said.
“Our system has proved to be very reliable and very efficient,” he said.
Limitations of testing
Dr Pain said a positive wastewater result could mean someone was currently COVID-19 positive or that they had recovered from virus and was shedding it in their waste.
The test itself didn’t show whether someone was still infectious.
“That’s why it’s so important to follow up on these positive samples when there is one,” he said.
“What we are really looking for is the unexplained positive samples.”
And for Mr Boland and his team, the work on the ground isn’t always glamorous.
“When you’re working at sewage treatment plants, poo stinks, there’s no secret about that, it’s not a surprise to anyone,” he said.
But Mr Boland was proud to be part of the COVID-19 response, helping keep the community safe.
“The implications of something like COVID taking hold in the NT is pretty dire,” he said.
“As a member of the broader NT community you’ve got to step up and take responsibility when you can.”
This article was originally published on the ABC website on Sunday 15 August 2021 and appears with permission.
The shuttle is attached to a bottle to protect it from wet wipes and other things which should not be flushed (ABC News: Lauren Roberts).
Dr Pain says he is pleased by how the NT’s wastewater testing program is running (ABC News: Lauren Roberts).
