Background on Wastewater Testing in Yarmouth

Wastewater testingNews
Written By Jillian Werb

All samples are collected at the Yarmouth Wastewater Treatment Facility. Results reflect SARS-CoV-2 viral RNA present in wastewater from homes connected to public wastewater diversion. Homes on a septic-based effluent system are not reflected in treatment facility samples.

After collection, samples are sent to the laboratory at St. Joseph College to isolate SARS-Co-V-2 RNA from the wastewater sample. Two parts of the nucleocapsid gene (N1 and N2) from the SARS-Co-V-2 genome must be found in the sample for it to be considered positive.

This helps us understand whether viral levels found in wastewater are going up, staying the same, or going down.

When the virus is found in a sample, the laboratory reports test results in copies of SARS- CoV-2 RNA per milliliter wastewater sample (copies/mL).

Frequently Asked Questions

Is wastewater testing effective in predicting COVID-19 outbreaks?

Several reports suggest that wastewater testing can predict the occurrence of future cases of COVID-19, usually by about 4 to 6 days.

• The U.S. Centers for Disease Control and Prevention found that wastewater concentrations of SARS-CoV-2 in a Southeastern U.S. wastewater treatment facility in late April through early June correlated with confirmed cases of COVID-19 that occurred 4 to 6 days in the future. [Source: CDC COVID-19 Sewage Surveillance webinar presented to the Council of State and Territorial Epidemiologists on July 8, 2020. [CDC COVID-19 Sewage Surveillance webinar presented to the Council of State and Territorial Epidemiologists on July 8, 2020 https://cste.sharefile.com/share/view/s552abc13bbc436d8]]

• Biobot analyzed wastewater from a major urban treatment facility in Massachusetts, between early January and May 2020, for SARS-CoV-2. They first detected the virus on March 3, followed by an exponential increase in viral concentration from mid-March to mid-April and a subsequent decline. “Viral titers [concentrations] in wastewater correlated with clinically diagnosed new COVID-19 cases, with the trends appearing 4-10 days earlier in wastewater than in clinical data.” [Source: Fuqing Wu, Amy Xiao, Jianbo Zhang, et al. SARS-CoV-2 titers in wastewater foreshadow dynamics and clinical presentation of new COVID-19 cases. medRxiv 2020.06.15.20117747;
doi: https://doi.org/10.1101/2020.06.15.20117747]

• The University of Arizona used wastewater testing to identify a dormitory with potentially infected individuals. Following the positive wastewater sample, the University tested all 311 individuals who lived and worked in the dormitory and found two asymptomatic students who tested positive. The students were quickly quarantined, averting further transmission of the virus. [Jaclyn Peiser, Washington Post, August 28, 2020. https://www.washingtonpost.com/nation/2020/08/28/arizona-coronavirus-wastewater-testing/

• See also the following reports:

o First confirmed detection of SARS-CoV-2 in untreated wastewater in Australia: A proof of concept for the wastewater surveillance of COVID-19 in the community. By Ahmed W, Angel N, Edson J, Bibby K, Bivins A, O’Brien JW, Choi PM, Kitajima M, Simpson SL, Li J, Tscharke B, Verhagen R, Smith WJM, Zaugg J, Dierens L, Hugenholtz P, Thomas KV, Mueller JF. Sci Total Environ. 2020 Aug 1;728:138764. doi: 10.1016/j.scitotenv.2020.138764. Epub 2020 Apr 18.

o SARS-CoV-2 RNA in wastewater anticipated COVID-19 occurrence in a low prevalence area. By Randazzo W, Truchado P, Cuevas-Ferrando E, Simón P, Allende A, Sánchez G. Water Res. 2020 Aug 15;181:115942. doi: 10.1016/j.watres.2020.115942. Epub 2020 May 16.

o First detection of SARS-CoV-2 in untreated wastewaters in Italy. By La Rosa G, Iaconelli M, Mancini P, Bonanno Ferraro G, Veneri C, Bonadonna L, Lucentini L, Suffredini E. Sci Total Environ. 2020 Sep 20;736:139652. doi: 10.1016/j.scitotenv.2020.139652. Epub 2020 May 23.

How is wastewater sampled?

The Town’s wastewater treatment plant operators collect 24-hour composite samples that are representative samples of wastewater coming into and going out of the treatment plant as part of their normal operation. All samples are collected in accordance with U.S. EPA sampling protocols to ensure that they are representative of the incoming flow. A portion of the incoming wastewater sample is sent to the lab for SARS-CoV-2 RNA testing with test results available in 3-7 days.

How are test samples used in our community and elsewhere?

Yarmouth Community Coronavirus Task Force members, town leadership, and the town health officer will use these test results, along with many other pieces of information, to decide how best to support the health of the town.

This data will also be reported to the Maine Centers for Disease Control and the U.S. Centers for Disease Control and Prevention (CDC) to support their efforts to initiate a National Wastewater Surveillance System (NWSS).

What are the advantages of wastewater infectious disease surveillance?

  • Wastewater testing has been used as a method for early detection of other diseases, such as polio.

  • SARS-CoV-2 can be shed in the feces of individuals with symptomatic or asymptomatic infection; therefore, wastewater surveillance can capture data on both types of infection.

  • Nearly 70 percent of Yarmouth households are served by our municipal wastewater system. Testing provides an indication of infection rates within the population served by the treatment facility.

  • Quantitative SARS-CoV-2 measurements in untreated wastewater can provide information on changes in total COVID-19 infection in the community contributing to that wastewater treatment plant.

  • Depending on the frequency of testing, wastewater surveillance can be a leading indicator of changes in COVID-19 burden in a community.

  • SARS-CoV-2 RNA detection in wastewater serves as a COVID-19 indicator that is independent of healthcare-seeking behaviors and access to clinical testing.

How is wastewater testing funded?

Funding for this project comes from the municipal grant program under the Keep Maine Healthy initiative administered by the Maine CDC.

Where can I find additional information about wastewater testing for SARS CoV-2?

Jillian Werb
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