Portland Water District has begun looking to sewage for clues on the ever-evolving coronavirus situation in what has been one of Maine’s consistent hotspots for COVID-19 cases.

The utility serving seven communities in Greater Portland is teaming up with a lab at Saint Joseph’s College in Standish to regularly test wastewater samples for the presence of COVID-19. In so doing, the district joins a growing number of utilities nationwide using waste to monitor virus levels in the local population and potentially learn about a surge even before the new infections show up in daily case counts.

The district plans to share the information with the Maine Department of Health and Human Services, an agency that includes the Maine Center for Disease Control and Prevention, as well as the state’s Department of Environmental Protection.

Scott Firmin, director of wastewater services at the Portland Water District, said samples from the facility’s Portland and Westbrook treatment plants will be tested weekly and potentially more often depending on interest and on “where the data takes us.”

Portland Water District employee Chris Cogan operates a machine on Tuesday that collects samples of wastewater for testing. A lab at Saint Joseph’s College in Standish then tests the samples for fragments of the virus that causes COVID-19 in hopes of monitoring virus trends in the local communities. Photo courtesy of Portland Water District

And at just $120 per sample, compared to $1,200 for other tests, Firmin views the three-month pilot project as another cost-effective way of monitoring the virus on a large scale rather than through testing of individuals.

“We’ll be testing anybody, essentially, who is contributing to our sewer flow,” Firmin said in an interview. “So it is capturing a larger population.”

Looking for the telltale biological “signals” of COVID-19 in the waste flushed down the toilet is not a new concept. Testing of wastewater has helped health researchers around the world detect and track outbreaks of polio, Hepatitis A and other infectious diseases and has even been used to track illegal drug use in some places.

Fragments of the virus that causes COVID-19 show up in the waste of infected individuals. Although scientific studies published in May suggested that the virus can survive in stool, studies are ongoing about the infection risk. And the wastewater treatment and disinfection process should kill any virus at that stage.

However, the presence of either active or inactive pieces of the virus could be useful sentinel tools in tracking COVID-19’s prevalence in a community.

Last week, the Greater Augusta Utility District began weekly testing of wastewater but is sending its samples to a Massachusetts-based laboratory, Biobot, that is testing samples from across the country. Augusta applied for and received a $24,000 grant from the Keep Maine Healthy fund to cover the estimated $1,200-per-test costs.

Facilities in four other communities in Maine – Bangor, Bath, Rockland and Sanford – conducted limited testing of wastewater in May, according to the Maine DEP.

The three-month project between Portland Water District and Saint Joseph’s College is somewhat unique, according to the partner organizations.

Saint Joseph’s College is using a testing method developed by Idexx Laboratories, the Westbrook-based veterinary diagnostics firm that is helping to dramatically expand COVID-19 testing capability at the Maine CDC’s lab in Augusta.

The test will look for RNA fragments of the virus in waste and then use the detected levels to attempt to extrapolate the virus’ potential presence in the wider community. Studies have suggested that people with COVID-19 may begin “shedding” the virus in their waste days before they begin exhibiting symptoms.

“Building a unique partnership between an educational institution and a public utility can provide an early warning to our public health systems,” Yolanda Brooks, an assistant professor of biology at Saint Joseph’s College and the primary investigator, said in a statement. “Previous studies have demonstrated that (the virus) . . . is shed in feces. Evaluating concentrations at the community level can help us monitor the number of cases including symptomatic, pre-symptomatic, sub-clinical, and asymptomatic cases.”

The testing being used by Saint Joseph’s is up to 90 percent cheaper than other methods and has the capability to detect the virus in low-prevalence areas, according to college and water district officials. Firmin said that means the system could be a useful tool for other wastewater facilities in Maine, a rural state with few densely populated areas.

“There is a hope what we are doing is developing a Maine-specific program that may be of interest to other utilities,” Firmin said.

Maine continues to have among the nation’s lowest COVID-19 infection rates despite the still-modest-but-growing number of vacationers arriving in tourist areas from other states. On Wednesday, the Maine CDC reported 29 new confirmed or probable cases of the virus – for a total of 3,866 to date – and that deaths of individuals with COVID-19 held steady at 121.

Cumberland County has consistently topped the state in terms of total cases and the per capita infection rate.

Just over 52 percent of all documented cases, to date, have been among Cumberland County residents, giving the county a case rate of 69.1 infections for every 10,000 residents compared to a statewide rate of 28.9. Androscoggin County had the second-highest case rate as of Wednesday at 50.6 infections per 10,000 residents while York County had a rate of 30.7, according to data from the Maine CDC.

Robert Long, spokesman for the Maine CDC, said the agency “welcomes all science-based efforts to learn more about how the virus that causes COVID-19 spreads in Maine.”

“We are monitoring research on the wastewater testing to determine how it could factor into Maine CDC’s analysis of how the virus spreads and how to limit its spread,” Long said in a statement.

Several large cities, including Boston, have been participating in wastewater testing programs in recent months.

Data from the Massachusetts Water Resources Authority, which operates the large treatment plant located on Deer Island in Boston Harbor, showed levels of RNA from the virus spiking from late-March to mid-April before falling precipitously through early-May.

Since then, the testing results showed relatively flat levels with some small peaks. Last month, the Massachusetts Water Resources Authority announced a six-month, $200,000 contract with Biobot Analytics to continue regular testing of wastewater.