In the race to track COVID-19 infection rates, wastewater testing takes the lead in speed, accuracy and cost. The Yale team in charge of wastewater tracking reflected on a week of low COVID-19 levels in New Haven sewage, and the team’s overarching role in the pandemic.

After a toilet is flushed, the waste traverses sewers underground, eventually flowing into a sewage treatment plant to be processed. Cities around the globe have invested in these centralized plants, where a community’s waste is concentrated and mixed together. At New Haven’s wastewater treatment plant, the “sewage sludge” filtered out of water has proven valuable for tracking COVID-19’s trajectory. The Yale team responsible for this effort is led by professor of chemical and environmental engineering Jordan Peccia and PhD student Alessandro Zulli GRD ’26.