A man walks by the Maine Center for Disease Control on Water Street in Augusta in March. Credit: Troy R. Bennett / BDN

Augusta’s water treatment district has teamed with a private firm and begun testing human wastes in city wastewater for the presence of COVID-19, and thus become the second state municipality to get a deeper understanding of how badly coronavirus has infected its residents.

Given that infected people shed some of the virus when they go to the bathroom, and that many COVID-19 cases remain undetected because some of those infected exhibit no symptoms, the Greater Augusta Utility District will work with a Massachusetts company called Biobot to test for the presence of COVID-19 in local wastewater, according to a statement released this week by city government.

Workers at Portland’s East End water treatment plant began work late last month with Saint Joseph’s College staff to test wastewater with the same goal in mind, saying that the tests allow a more accurate estimate of how many people are infected in large, populated areas like Portland.

During late July and August, the first two weeks of testing yielded no detectable COVID-19, but on Aug. 3, a third test showed a very small concentration of SARS-CoV-2 which Biobot said coincided with two reported cases of COVID-19 in Kennebec County, officials said.

Biobot has tested water in nearly 400 cities across the country. The tests will help Augusta control the spread of the virus and allow city leaders more data upon which to base decisions for the handling of city buildings, facilities, schools and other services, Augusta City Manager William Bridgeo said in the statement.

“Wastewater testing and monitoring of the results will continue to guide our efforts to return to the new normal,” Bridgeo said.

The wastewater tested will come from thousands of homeowners, commercial establishments and industries in Augusta, Hallowell, Manchester, Monmouth and Winthrop. It is collected through a system of underground pipes that flow into a wastewater collection system.

Test results are available at the city government website, augustamaine.gov.