Topeka sewage sees high percentage of genetic remnants of COVID-19 when compared to 330 other communities

Tim Hrenchir
Topeka Capital-Journal
Large tanks of wastewater in the aeration area of the Oakland Wastewater Plant, 1115 N.E. Poplar Ave., incorporate air in the filtering process Monday afternoon. Samples were tested by labs to show amounts of genetic remnants of COVID-19.

Topeka's Oakland Wastewater Treatment plant recently had more genetic remnants of COVID-19 floating in its sewage than 91% of the other facilities evaluated in a nationwide study. 

The Oakland plant at 1115 N.E. Poplar Ave. is among about 330 treatment plants that took part in the study by Biobot Analytics, a Cambridge, Mass.-based wastewater epidemiology firm.

The company tested sewage for the presence of SARS-CoV-2, the virus responsible for COVID-19.

The study's results offer a rough measure, in hindsight, of how often people in the areas involved were infected with the coronavirus, said Dan Zeller, plant operations manager for the city's water pollution control division.

A small red dot and line represent the portion of the study where Topeka is included showing how the city's sample of wastewater showed a higher concentration level of COVID-19 than 91% of all the nationwide sites for last week's testing.

People who have the coronavirus shed it through their urine and feces, which enter public wastewater systems, Zeller said.

"It's like the equivalent of a snake's skin when it sheds it," he said. "It just tells you 'This was here.'"

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Wastewater testing can tell you how widespread COVID-19 was

Genetic remnants of COVID remain in wastewater, where they can be extracted and matched against markers keyed to COVID to offer insight into how widespread the virus was in the area involved, said Sylvia Davis, the city of Topeka's deputy director of operations for utilities.

The coronavirus doesn't survive in sewage, so being around wastewater containing its genetic remnants doesn't increase a person's risk of getting COVID-19, Davis said.

Sylvia Davis, Topeka's deputy director of operations for utilities, looks over the data compiled by Biobot Analytics, a Cambridge, Mass.-based wastewater epidemiology firm. The results showed Topeka had more genetic remnants of COVID-19 in its sewage than 91% of the other facilities in the nationwide study.

This community's North Topeka and Sherwood Water Treatment Plants weren't involved in the Biobot study, Zeller said.

The Oakland plant receives about two-thirds of this community's sewage, and also treats some wastewater from surrounding communities that include Holton and Lawrence, he said.

The results of the recent testing show how the wastewater from the Oakland plant compares to other sampling sites from around the country, Davis said.

Plant employees collected samples at different points in the treatment process by using a rope to lower a large jar into the wastewater stream, Zeller said.

The samples were taken away for testing, which initially showed the presence of genetic COVID remnants at the Oakland plant was comparatively low.

Dan Zeller, plant operations manager for Topeka's water pollution control division, shows how a bottle on a rope is used to collect samples of wastewater at the first point of entry into the Oakland Wastewater Plant.

The first tests there, conducted June 15 and 17, showed the Oakland plant was in the 19th and 15th percentiles, respectively, among testing sites nationwide, Davis said.

That meant the plant had a higher concentration of coronavirus than was found in 19% and 15%, respectively, of samples sent in from other facilities.

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Summer saw increase in amount of COVID-19 in wastewater

But as the summer proceeded, the Shawnee County Health Department reported it was seeing an increased number of COVID cases, due largely to the disease's delta variant.

Meanwhile, the presence of COVID remnants in the wastewater at the Oakland plant also rose.

Davis provided figures showing that facility recorded percentile rankings of the following:

• 29% on June 22.

• 11% on June 24.

• 76% on June 29. 

• 4% on July 1.

• 7% on July 6.

• 77% on July 8.

• 93% on July 13.

• 68% on July 15.

• 91% on July 20.

• 67% on July 22.

• 86% on July 27.

• 76% on July 29.

• 90% on Aug. 5.

• 76% on Aug. 10.

• 82% on Aug. 12.

• 67% on Aug. 17.

• And 91% on Aug. 19.

Large debris, such as rocks and plastic, are processed out of Topeka's wastewater.

Local officials say figures from the study might more accurately reflect how widespread COVID was in a community than health department figures do.

That's because the latter don't reflect the presence of COVID in asymptomatic people who didn't get tested and aren't accounted for in the health department figures.

But the wastewater testing figures accurately reflect the presence of COVID in symptomatic and asymptomatic victims, because it detects remnants being shed through the urine and feces of everyone who's had the coronavirus, Davis said.

"If you had the virus, you're going to shed it," she said.