Sewage testing for coronavirus infections in Lawrence helps health officials prepare for surges

photo by: Philip Heying/Journal-World File Photo

The City of Lawrence Wastewater Treatment Facility at 1400 E. Eighth St., is pictured in this file photo from March 13, 2009.

A study that tests for parts of the coronavirus in sewage has helped give public health workers advance notice of virus surges, and officials say this kind of testing could eventually help them direct resources to the places that need them the most.

As part of a study contracted through the University of Kansas School of Engineering, the City of Lawrence has been taking weekly sewage samples at both of its wastewater treatment plants to test for components of the virus shed in feces. The city has also been sharing that data with local and state health departments.

Lawrence-Douglas County Public Health spokesman George Diepenbrock said that the presence of the virus in wastewater has served as an early predictor of surges in positive cases, providing about a week’s notice and giving the health department valuable lead time. Research has shown that COVID-19 concentrations in wastewater rise about a week before a surge in new cases, and that both symptomatic and asymptomatic people with the virus shed components of it in their feces.

“As we saw those levels go up, that was an indicator that we need to prepare,” Diepenbrock said.

The study began in April, soon after the coronavirus pandemic arrived in Kansas. Belinda Sturm, associate vice chancellor for research at KU, has been communicating emerging research to the city and local and state health departments, according to a previous city news release.

Diepenbrock said that at this point, the main way the health department has used the data is to adjust its staffing. In particular, the health department can see whether it needs to add more disease investigators to inform people of their test results and initiate the contact tracing process for positive cases. If wastewater sampling indicates a surge is coming, Diepenbrock said the department can prepare to hire additional staff, call in the help of retired personnel or internally reassign some workers to different duties.

Thus far, the city has only been sampling wastewater from its two sewage treatment plants: the Kansas River plant and the Wakarusa plant. But city officials said they might eventually test sewage at other locations to find out which neighborhoods have the highest rates of infection.

Trevor Flynn, general manager of environment, health and science for the city’s Municipal Services and Operations department, said in an email to the Journal-World that as part of the study, the city has been testing out a process for collecting samples from manholes in neighborhoods. For now, he said the city would be using two manhole locations to assess the feasibility of expanding the sampling program. He said it would take samples from those sites over the next month as resources allowed, and that KU would use the data for further analysis.

“The correlations would improve our understanding of the wastewater data and how it relates to community prevalence,” Flynn said.

If the neighborhood-level testing proves effective, the health department could use it to better tailor its virus response to specific parts of the city that need it most, Diepenbrock said.

For example, he said if wastewater sampling showed that the virus was concentrated in a certain neighborhood or area, the health department could inform those residents that their area had a high concentration of cases. The department could also offer more testing for residents of that neighborhood, perhaps even setting up a mobile testing location, in an effort to quickly identify infected people in the area before the virus spreads more.

“If we could get a handle on it, contain it, hopefully it wouldn’t contribute to a larger spike,” Diepenbrock said.

More detailed reports comparing the prevalence of COVID-19 in wastewater and the local curve of positive cases are available on the city’s website, lawrenceks.org.

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