MARSHALL — A lot of concern about the COVID-19 pandemic in Minnesota has been focused on the impact on people — and with good reason. But the response to the pandemic could also have some potentially nasty effects on public infrastructure, like our sanitary sewer systems.

Wastewater treatment operators in Marshall and around the state are trying to get the word out, asking the public not to flush disposable wipes and other products down the toilet. With toilet paper scarce in some stores as people stock up, there’s a chance that Minnesotans could turn to alternatives like tissues, baby wipes or paper towels, the Minnesota Pollution Control Agency said Monday. But those products — even the ones marked “flushable” — will clog sewers.

“It doesn’t dissolve, and it doesn’t flow out real good,” compared to toilet paper, said Marshall wastewater superintendent Bob VanMoer.

VanMoer said there are a couple of key risks the Marshall municipal wastewater plant is currently facing, and both are being affected by COVID-19. One is the possibility that people will flush improper materials during a toilet paper shortage. The other is improperly connected sump pumps dumping stormwater into the sanitary sewer, during spring melting and rains.

On the flushing front, “We haven’t had too many problems yet,” VanMoer said. However, he said it’s enough of a concern that he’s using advertising and social media to get the word out to people not to flush disposable wipes.

This month, the MPCA has also been warning people not to flush disposable wipes. Although many disposable wipes say they are flushable on the packaging, they don’t break down the same way toilet paper does.

The wipes snag on imperfections in sewer pipes, and catch debris and grease that can plug the pipes, the MPCA says. They also get drawn into sewer line and wastewater treatment plant pumps. Those clogs have to be cleared out manually, the MPCA said.

VanMoer said the clogs formed by disposable wipes are likely to damage the sewer lines in homes before they even get into the city sewer. It’s another reason why the wipes shouldn’t be flushed.

VanMoer said the other concern for the Marshall wastewater plant this time of year is increased flow. During the rains over the past weekend, flow at the plant jumped to around 5 million gallons a day. While the flow was starting to come down, VanMoer said Wednesday it was still high.

Stormwater and groundwater aren’t supposed to go into the sanitary sewer. While the city of Marshall does allow people to discharge their sump pumps into the sanitary sewer by permit during the winter months, the connections aren’t allowed past April 1.

With social distancing guidelines in place because of COVID-19, VanMoer said city staff haven’t been going into homes to disconnect the sump hookups. He urged residents to disconnect their sump pumps from the sanitary sewer.