John Leavell bends down, catching a 50-pound, cast-iron manhole cover with a T-shaped hook and sliding it aside. He then attaches one end of a thin hose to a battery-powered pump and drops the other into the darkness below. “Yesterday we couldn’t retrieve any samples,” says Leavell, a contractor for the non-profit Current Water. “Everything just froze. It was not pleasant.”
The manhole, located outside the Baton Show Lounge in Chicago, is his second stop of the day. Once he and his team have pulled, labeled and double-bagged two 50-milliliter bottles of raw sewage here, they’ll head across town to sample another manhole — and then deliver their bounty to a microbial ecology lab. Rinse and repeat, four days a week.
It’s a ritual that’s taking place across the country. In September 2020, the CDC launched its National Wastewater Surveillance System to monitor for COVID-19 upsurges using clues that Americans flush away. It’s become the first widespread use of wastewater-based epidemiology since the technique was used to track polio in the mid-20th century, and already it’s filling critical gaps in clinical testing.
