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UD’s CEWER takes on analyzing wastewater to track COVID-19

Eric Wommack
CEWER team Kali Kniel , Eric Wommack, Brienna Anderson, Pushpinder Litt, and Adrienne Shearer

New Castle County started analyzing its sewer water for COVID-19 last spring.

Late last year, it moved that analysis to the University of Delaware’s Center for Environmental and Wastewater-based Epidemiological Research (CEWER).

Delaware Public Media’s Sophia Schmidt talks with CEWER director Kali Kniel about this work.

County officials say CEWER can do the job faster than Biobot and “at a fraction of the cost.”

“In August, UD started running some of our samples in their own lab but we were still sending samples to Biobot until we were confident that both labs were producing comparable results,” said Brian Cunningham, spokesman for County Executive Matt Meyer’s office, in an email. “As of January 1st, UD is exclusively analyzing all of our samples.”

CEWER researchers concentrate and analyze the wastewater for genetic material from the virus, which is shed through stool. 

Kniel says the data can’t predict a certain number of cases—but can indicate whether cases in an area are going up or down. 

“That’s really the best thing that it’s used for,” Kniel said. “We’re trying to do trend analysis. We’re trying to look at what’s happening over time.”

Kniel says on UD’s campus, researchers look at places where a critical mass of students live. 

“What we were able to do is then identify where we found virus and then communicate that to student health, and work with student health to try to figure out if there were individuals there that should go for clinical testing, or may have been positive for the virus,” Kniel said. 

Kniel notes it’s unclear whether virus detected in wastewater indicates a new case or one where the person has recovered. But she expects the data to be particularly useful over the coming months. 

“We may be able to see whether or not people are protected by the vaccine and are not shedding the virus as much,” she said. 

Viral concentrations from sampling sites such as Christiana Hospital, Delaware City and the City of Newark can be viewed at the County’s wastewater testing webpage

The state has not yet gotten involved with wastewater testing. 

State Division of Public Health Medical Director Dr. Rick Hong said in a statement that analyzing wastewater could provide “some insight into possible outbreak monitoring,” but that there are still many logistical questions to be answered. 

“How will that community population be monitored?” Hong wrote. “Is there enough manpower to go into the community to identify (test) potential patients? How is the data to be reported to the public once identified? What if the viral contamination is triggered by transient persons who are no longer in the community (passed by in a restaurant, etc.)? Is there authority to impose testing on the community if an organism is identified?"

"We are finding that simply knowing that a virus is found in wastewater may or may not necessarily mean that there will be an outbreak," he added. "We are currently trying to define more effective protocols that can provide actionable information.”

Hong said DPH is aware of CEWER’s work—but that CEWER is “still in its early phases of exploratory work,” and the state is still responding to “more immediate public needs” in the COVID-19 response.


Sophia Schmidt is a Delaware native. She comes to Delaware Public Media from NPR’s Weekend Edition in Washington, DC, where she produced arts, politics, science and culture interviews. She previously wrote about education and environment for The Berkshire Eagle in Pittsfield, MA. She graduated from Williams College, where she studied environmental policy and biology, and covered environmental events and local renewable energy for the college paper.
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