Research scientists at the Metropolitan Wastewater Treatment Plant in Saint Paul continue to monitor levels of the SARS-CoV-2 virus entering the plant, now including the newest variant, Omicron, in their study.
The variant, they say, has begun to reveal itself in Metro Plant influent wastewater. At the same time, Minnesota Department of Health officials report that testing has detected Omicron in a comparatively small, but growing number of COVID-19 cases at year’s end.
Wastewater, otherwise known as sewage, emerged last year as an important indicator of the prevalence of the virus among the population the wastewater system serves. Every day in the Twin Cities metro area Metropolitan Council Environmental Services treats 250 million gallons of wastewater from 111 communities.
Wastewater surveillance supplements COVID-19 testing
In a small and unpretentious lab at the giant Metro Plant, research scientist Steve Balogh extracts tiny droplets of viral genetic material from wastewater samples. He stores them in tiny vials, frozen at 112F below zero, and delivers them weekly to research partners at the University of Minnesota Genomics Center for identification and analysis.
“Since early 2021, we’ve monitored the variants of concern that have emerged,” said Balogh. “We tracked the rise of Alpha last spring, its replacement by Delta last summer, and now we’re observing the first signs of Omicron, which could end up replacing Delta.”
Viruses like SARS-COV-2 continue to change and mutate as they circulate. Working with the university, Balogh shares data with the health department to compare findings from wastewater sampling with COVID-19 testing and infection rates.
Wastewater sampling does not confirm individual cases or provide detailed information about how and where outbreaks occur. But it is an unbiased measure of disease prevalence in the service area, supplementing diagnostic testing.
Delta variant dominates, for now
Environmental Services also shares wastewater samples with projects run by the University of Minnesota Medical School and the Center for Disease Control National Wastewater Surveillance System, respectively, which do their own independent analyses.
While Delta continues to be the dominant variant observed locally, researchers anticipate that we’ll continue to see more of the newest variant, Omicron. However, it’s difficult to know with certainty what this virus has in store. Even more reason for this field of research.
“Wastewater surveillance, locally, nationally, and globally is a rapidly emerging field,” said George Sprouse, who manages process engineering, research and development, and air quality for Environmental Services.
“Our research increases our capacity to respond to future outbreaks of infectious diseases and our ability to improve upon our monitoring processes,” said Sprouse. “Monitoring for disease agents in our wastewater influent is a new way for us to continue to fulfill our mission to help protect public health and the environment.”
Minnesota Department of Health information on COVID-19 and staying safe