Research teams have found concentrations of the virus which causes COVID-19 in the wastewater of several University of Idaho residence halls and Greek Life chapters.
UI Biology Professor Eva Top, UI Research Support Scientist Thibault Stalder, and UI Civil and Environmental Engineering Professor Erik Coats work on the teams evaluating the wastewater.
Research Scientist Cindi Brinkman and Lab Manager Erin Mack analyze City of Moscow and UI wastewater samples at the Coats and Top labs, respectively. Nine sewer locations have been chosen for testing UI’s wastewater. Individual dorm floors and Greek chapter houses are not tested for time- and cost-effectiveness, Coats said.
High concentrations of the virus that causes COVID-19 are detected in campus wastewater relative to the city’s wastewater, collected at the City treatment facility across the Palouse Mall, where the water can be diluted, Stalder said.
“It’s a way to test a whole pool of people at once,” Top said. “On campus, you test the different houses, and then when you see that one has a lot of (the virus which causes COVID-19) in the sewage, you know you should go test those students.”
Stalder said UI decided to use this method of detection because studies from Australia, France and the Massachusetts Institute of Technology (MIT) showed the organism which causes COVID-19, SARS-CoV-2, could be detected in the wastewater.
The teams do not estimate case numbers. Instead, they graph virus concentration in wastewater over time.
The teams used a method which lost a lot of the virus in the process, so they switched to a method called ultra-filtration.
Ultra-filtration uses a tube with a membrane in the middle. Samples of wastewater are put in the top of the tube and are centrifuged, or rapidly spun, until the water goes through the membrane, leaving the virus stays in the top portion of the tube due to the size of the membrane and the pores.
After this process, Top and Coat’s teams deactivate the virus samples.
It is very unlikely the virus in the wastewater is infectious, though, Stalder said.
The entire process takes about 10 hours to complete and share with UI officials. The team’s goal is to collect and analyze samples from all nine sites twice per week. The samples are taken Mondays and Thursdays and analyzed the same or following day. The teams officially started collecting and analyzing samples on Sept. 3.
According to Coats, initially the virus was not detected in most campus sampling locations, but more recently there have been some concerning spikes.
Elmer Johnson, UI water systems manager, and his team collect wastewater samples once or twice a day from the nine locations decided upon through collaboration with Top and Coat’s teams. UI ordered an auto-sampler to install in a sewer manhole to collect samples over a 24-hour period.
Biobot is a private company from MIT making a national effort to test wastewater. According to Stalder, the company originally estimated Moscow had thousands of COVID-19 cases, but this seemed unreasonably high. The company has updated its system since June, but Stalder and the team remain unsure of its accuracy.
Stalder said a study showed half of those infected with the virus are asymptomatic and either never show symptoms or show symptoms later (presymptomatic).
“If we observe an increase, and we need to be very fast in our analogies, we might be able to pick up a start of an outbreak because we see the concentration increasing, before even the people get tested,” Stalder said.
Coats does not see the value in comparing across wastewater treatment plants because of the varying regions and the virus spread across populations is not well understood.
Stalder said the impacts of their research are normally not seen for a few years, so it is rewarding to see them so rapidly now.
“I am enjoying the fact we’re a resource; we’re helping; we’re contributing something, I think, that’s meaningful,” Coats said. “It’s bigger than us.”
UI resident and Greek life wastewater testing will continue after Thanksgiving break.
Kim Stager can be reached at [email protected] or on Twitter @journalismgoals.