As COVID-19 continues its unrelenting rampage, wastewater plant managers and university researchers are ramping up their efforts to monitor wastewater for SARS-CoV-2, the virus that causes the disease. Their goal is to give public health departments a powerful tool: an early warning system for new outbreaks in communities. In Yosemite Valley, for instance, wastewater testing revealed the presence of the virus in the community before swab testing of individuals showed a problem.
“There’s a time delay before cases appear in a community and in the medical system,” says Katy Graham, a graduate student at Stanford University who is leading development of laboratory methods that will link trends and concentrations of the virus’ RNA (ribonucleic acid) in wastewater to the virus’ prevalence and spread in communities. “Individuals can shed the virus for days or weeks before they are aware they have it. Tracking its RNA in wastewater can identify COVID infections in the community more accurately and faster than other types of testing.”
Wastewater treatment plants from around the Bay are submitting samples of their untreated waste (influent) to labs at Stanford and other universities. Despite the seemingly hazardous nature of the samples, there have been no instances of virus transmission from the testing process, says Graham. “We are detecting viral RNA, which is not the same thing as infectious or intact viruses. RNA can be detected in a sample without infectious virus present.” Although risk of transmission from the samples is low, the Stanford team takes extra precautions, Graham says. “We are very careful, we use lots of PPE and N95 masks and lab coats and biosafety hoods. We socially distance.”
The East Bay Municipal Utility District (EBMUD) was one of the first wastewater dischargers to send samples to Stanford. The district first encountered COVID-19 when the Diamond Princess cruise ship arrived in Oakland in March about to overflow with waste. “They called us and said, ‘We’re desperate, we’re at capacity.’ We took the wastewater to our [Oakland] plant and treated it after sending some samples to Stanford,” says Eileen White, wastewater director for EBMUD. Since then, she has been coordinating the utility district’s efforts with public health agencies at the local, state, and federal levels, including the Centers for Disease Control and Prevention (CDC). White says the information gathered through wastewater testing can be used to guide county health officers in making decisions about shelter-in-place orders.
East Bay Dischargers Authority general manager Jackie Zipkin says there have been many different efforts by dischargers and researchers moving in parallel to help track COVID-19. While Stanford’s focus is primarily research and model development, UC Berkeley is gearing up to test as many as 100 samples per day, she says. And EBMUD is now building capacity to perform more testing in its own labs. They’ve also tested their treated effluent before it is discharged into San Francisco Bay. “It does not have COVID — the treatment process kills it,” says White. “So if you’re a swimmer in the Bay, the answer is ‘No, you won’t get COVID.’”
A working group of researchers from Stanford and UC Berkeley, public health officials, and treatment plants convened recently to coordinate efforts, says Zipkin. A subset of those leaders has formed a steering committee tasked with framing a regional wastewater monitoring program.
But a big challenge for all the labs moving forward is cost. “There’s the cost of setting up the lab itself, of performing the analysis, which can cost $200 or more per sample, and the cost to the agencies to collect the samples and ship them off,” says Zipkin. She says most wastewater agencies are covering the cost of the labor to take and ship samples to labs as well as to analyze samples. “The perspective of the wastewater community is one of eagerness to help,” she says. “I think every agency wants to send samples if they can be useful. We want to see this work moving forward because we all want to do something and feel it has a lot of promise.” White says the CDC has promised that funding will be forthcoming.
Zipkin points out that a regional program will help home in on an outbreak: “The more different data sources you have to evaluate trends and try to triangulate an outbreak, the better. [A regional program] presents an opportunity to do that.” Wastewater sampling saves resources too, she says. “You can look at a whole neighborhood or building versus testing every individual in the community.”
Top photo: Two EBMUD wastewater inspectors, Gabriela Esparza and Zachary Wu, collect a sample. Photo: Ben Glickstein, EBMUD