Each day, workers at the wastewater treatment plant in New Haven, Connecticut, siphon off a bit of sewage and put it in a cooler. Then, researchers from Yale University swing by to pick it up. In their hands, that pile of refuse is a key tool to predict the trajectory of the local COVID-19 outbreak.
Other cities besides New Haven are starting to monitor virus particles in their sewage. The Yale researchers were able to see an increase in the levels of virus one week earlier than the case counts went up for the city.
Since sewer systems in developed countries are interconnected, sampling anywhere along the sewage path could give researchers a quick and fairly comprehensive snapshot of health in a given city neighborhood.