After you take care of business and push the handle on your toilet, it's out of sight, out of mind, right?

But when the pandemic started, some folks, like Pieter Van Ry, realized there's actually gold in that stuff.

"How it began was I actually, on a Sunday morning, woke up and I read a Popular Mechanics article," he said. This was early on, March 2020, when the first wave of COVID-19 infections hit. "At the end of that article, it said, 'If you have a wastewater facility and you're interested in participating in this study, please contact us.'"

As a matter of a fact, he did happen to have a wastewater facility.

Van Ry directs South Platte Renew. Its Englewood treatment plant serves 300,000 people southwest of Denver. That article Van Ry read had a catchy title: How Poop Offers Hints About The Spread of Coronavirus.