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Principal investigator Jordan Peccia explains why and how we use wastewater for SARS-CoV-2 surveillance

Monitoring the concentration of SARS-CoV-2 in wastewater can be an important tool for tracking COVID-19 outbreaks within a community. People with an active infection (symptomatic or asymptomatic) can excrete the virus in their stool, which is conveyed to a wastewater treatment plant where it is mixed—and during primary treatment—concentrated into primary sludge. In the New Haven, CT metropolitan area, the SARS-CoV-2 content in one daily primary sludge sample represents a population of 200,000 people. Throughout the U.S., approximately 275 million Americans are served by a wastewater treatment facility.

A schematic representation of a typical wastewater treatment plant. The Yale SARS-CoV-2 Wastewater Surveillance Initiative uses primary sludge samples for testing.

Our team has demonstrated that we can track a COVID-19 outbreak  in a community by measuring the concentration of SARS-CoV-2 RNA in primary sewage sludge. Because a person sheds virus in their stool before symptoms occur, and generally people only get a test for the virus after symptoms occur, changes in the SARS-CoV-2 concentrations in primary sludge may appear ahead of other measures used to track outbreaks, including testing data.  As a leading indicator, information on the amount of viral genomes in wastewater can be utilized by local and state officials to implement public health measures.

Read our latest wastewater surveillance report.


Please refer to the Yale Wastewater Surveillance Initiative’s preprint or protocols page for more in-depth information on our approach. Contact Jordan Peccia, Professor of Environmental Engineering at Yale University, with comments or questions: Jordan.Peccia@yale.edu