One evening in March 2020, as wastewater researcher Robert Delatolla prepared dinner at his Ottawa home, his wife wondered aloud: Was it possible to detect the novel coronavirus in the city’s sewage system? Delatolla had spent years of his environmental engineering career exploring wastewater treatment technologies—not detecting viruses. He scoffed at the idea. “I said obnoxiously, ‘It’s not going to work,’” recalls the University of Ottawa professor. A few days later, Delatolla realized his wife was right. In late March, Dutch researchers announced wastewater surveillance efforts in the Netherlands were successfully identifying the virus behind COVID-19even before cases are officially reported. Delatolla and his lab team struggled to get a similar system up and running. “By April 8, 2020, we managed to have our first detection,” he said. “This was our first detection of SARS-CoV-2 in wastewater in Canada.” The first but not the last. For more than two years, research groups across the country — and around the world — have been using human waste to track the rise and fall of levels of the coronavirus. The approach can also be used to track the viruses behind monkeypox and polio. It is capable of detecting antimicrobial resistant bacteria or toxic drugs. And researchers say the public health possibilities are limitless. However, the future of wastewater testing remains uncertain. Some Canadian scientists are concerned about precarious funding. Others believe that scaling up global surveillance is necessary to track emerging pathogens—but that it is also fraught with challenges. What is clear is that this kind of surveillance system works. And it starts with something we all just brush off. Delatolla, right, and applied science student Chandler Wong look at a graph showing the detection of COVID-19 genetic material in wastewater from a sample collected in the past 24 hours, at the University of Ottawa on Sept. 14. (Justin Tang/CBC)
From the sewage treatment area…
On a warm August morning, you can smell the pungent brown sludge flowing through a concrete channel at a sewage treatment facility in the east end of London, Ont. It is one of dozens of Canadian sites participating in wastewater research projects in collaboration with various universities and public health agencies. About 20,000 cubic meters of sewage – an amount that could fill eight Olympic-sized swimming pools – reaches this facility every day. It’s full of all the random trash that flushes their toilets. human waste, of course, but also cereal, tampons, needles and masks. “We’re taking t-shirts, clothes, wet wipes,” said Andrew Nimich, a shift operator at the site. A concrete channel filled with sewage at a treatment facility in the east end of London, Ont. — one of dozens of Canadian sites participating in wastewater research projects in collaboration with universities and public health agencies. (Lauren Pelley/CBC) And, he adds, many different pathogens that are invisible to the naked eye. But it wasn’t until the COVID-19 pandemic hit that his team realized how useful the sewage data could be when researchers from nearby Western University began requesting sewage samples to begin tracking SARS-CoV-2. Now, collecting samples for scientific research is a regular part of the team’s weekly routine. The process is as follows: First, the filters remove all debris, then the wastewater enters an autosampler. The machine takes small 200 milliliter samples once every 15 minutes over a 24-hour period, which flow into a 19-liter refrigerated jug. A few times a week, Nimitz pours rations into jars that he delivers to the Western research team as its members travel to the city’s various sewer sites to fill a cooler with their liquid gold. What comes from this sewage treatment plant? “We’re taking t-shirts, clothes, wet wipes,” says Andrew Nimich, a shift operator at the site. And, he adds, many hidden pathogens. (Lauren Pelley/CBC)
…In the laboratory
After the jars of sewage were delivered to the researchers, located inside a containment lab on campus, team members separated the liquid into 40-millimeter test tubes. These test tubes are spun in a centrifuge at up to 12,000 revolutions per minute, collecting all the solid waste and any pathogens they contain. Dressed in personal protective equipment, microbiologist Eric Arts describes what happens next: The solid material is condensed into a tiny pellet, which is then suspended in a solution capable of breaking apart any bacterial cells or viruses, releasing the hidden genetic the code. “It retains the viral RNA — so, the genetic material of the virus that’s in the wastewater — and that viral RNA, we can take out in an extraction process,” Arts said. To track SARS-CoV-2, the team analyzes this genetic code in two different ways. Test tubes containing sewage are spun in a centrifuge at up to 12,000 revolutions per minute, concentrating all solid waste into a tiny pellet. (Lauren Pelley/CBC News) The first is the polymerase chain reaction (PCR) test, a term now familiar to many. It is a form of testing that involves making millions of copies of the genetic material found within a given sample until it is detected by a PCR machine, either from a single nasal swab or from a sewage sample containing pathogens shed by hundreds of thousands of people. The goal is simple: Determine whether a specific type of virus — in this case, SARS-CoV-2 — is present. The second type of analysis done on viral RNA is sequencing, to determine the sequence of nucleotides—the basic building blocks of RNA and DNA, which create a blueprint that provides the instructions for building a particular virus or other organism. SARS-CoV-2, for example, contains more than 30,000 nucleotide sequences, which can be slightly different depending on the variant of the virus. “We then do a calculation of the percentages of each variant of interest in the wastewater sample,” Arts said.
Effluent testing exploded during the pandemic
Similar systems are now in place around the world, primarily to track SARS-CoV-2. The aptly named ones CovidPoops19 The project — a collection of coronavirus wastewater surveillance efforts by researchers at the University of California, Merced — shows that the number of global monitoring sites has exploded to about 3,600, involving more than 280 universities and spread to 70 countries. And now researchers are using similar techniques to track other pathogens. University of Ottawa Delatolla started publication of sewage signals for monkeypox on his personal Twitter account, from Ontario cities like Ottawa and Hamilton. South of the border, New York State officials contaminated sewage in several counties with the polio virusafter one person was paralyzed by polio infection. Lab technician Jian Jun Jia demonstrates using a pipette to mix the qPCR master reaction mixture with a sample of isolated genetic material extracted from sewage, at the University of Ottawa in Ottawa on September 14, 2022. (Justin Tang/CBC) Another new project, involving researchers at Stanford University and Emory University in the US, is tracking monkeypox by analyzing sewage samples from dozens of communities in 10 different states. The team has already received viral signals from nearly two dozen locations. The technology, to be clear, is nothing new. In his research on wastewater testing in early 2020, Delatolla realized that teams had been trying to use it for years to detect drug levels in city wastewater, from illegal drugs to pharmaceuticals. “I was amazed to go through the history and see that in 1974 they were doing this in Canada and they were going after polio,” he said. Everything old is new again, it seems. In part, Delatolla noted, because it’s so simple. “It’s very economical. It’s crazy,” he said. “You’re talking about a sample and a PCR test, to affect the health of a million people.” WATCHES | Here’s how scientists are using wastewater to detect levels of COVID:
How wastewater testing works, from the field to the lab
Scientists at Western University and staff at a wastewater treatment plant in London, Ont., gave CBC News an inside look at the step-by-step process for screening wastewater for pathogens.
The future of wastewater in science
But the future of wastewater testing looks murky. Will it continue to expand, alerting the world to the spread of viruses and potentially detecting new pathogens before they explode globally? Or will interest – and funding – disappear as the threat of COVID-19 fades? Those questions concern the more than a dozen Ontario labs whose funding is in place until March 2023, Delatolla said. Right now, he says, it’s unclear whether more cash will come after that. In Quebec, Officials restarted sewage testing efforts last spring after funding for a pilot project originally expired in December. And not all provinces rushed to implement it in the first place. “It just comes down to: Is there enough appetite to keep it funded?” Delatola said. Inside a containment lab at Western University, research technician Dilan Joseph divides a jar of sewage into test tubes. (Lauren Pelley/CBC) At the federal level, officials seem willing to continue exploring the possibilities. “It doesn’t bother anybody, nobody has to come forward for testing, it doesn’t rely on a significant amount of infrastructure, and it really gives us a pulse check of what’s going on,” said Dr. Guillaume Poliquin, vice-president-president of the Winnipeg-based National Microbiology Laboratory, which is run by the Public Health Service of Canada. “There’s a lot of potential there — not just for SARS-CoV-2, but for other pathogens as well.” Right now,…
