Development of a Wastewater Surveillance Program to Protect Public Health in Southeastern Michigan

Introduction The Coronavirus Disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome virus 2 (SARS-CoV-2), has exposed modern society's vulnerability to infectious diseases. Despite significant human tragedy and financial constraints, water resource recovery facilities (WRRFs) continue to provide clean water to shared waterways and protect the environment. Additionally, several wastewater utilities and their research partners have 'looked to the sewers' to help public health agencies track the spread of SARS-CoV-2 via wastewater surveillance. During the COVID-19 pandemic, public health officials have relied on clinical testing of symptomatic individuals to monitor the outbreak of SARS-CoV-21 . The approach is reactive since there is typically a time lag between the onset of disease and when the result of a clinical test is reported to a local health agency. Testing symptomatic individuals also fails to identify asymptomatic cases known to spread the disease. Wastewater surveillance is a disease-tracking tool that analyzes untreated wastewater for human biomarkers. Measurement of these biomarkers can provide an aggregated signal of public health in a community. The technique has been successfully implemented for the early detection of polio, as well as retrospective identification of hepatitis A outbreaks. Retrospective analyses suggest the signal of SARS-CoV-2 in wastewater can precede reported clinical cases by up to three weeks. Early detection of disease supports early response, such as public health decision-making and pop-up vaccination clinics. Additional applications of wastewater surveillance include monitoring for future disease outbreaks, antibiotic resistance, and health disparities6. A successful wastewater surveillance program requires collaboration between community leaders, wastewater utilities, epidemiologists, public health officials, engineers, doctors, and other scientists. At the heart of each program is the wastewater utility, whose knowledge of the sewer system is critical to correlating wastewater surveillance data to public health trends. This presentation highlights the role of the Great Lakes Water Authority (GLWA) in the development of an effective wastewater surveillance program in southeastern Michigan. The presentation includes a historical description of pre-pandemic research efforts at GLWA with Michigan State University (MSU) and the Detroit Water and Sewerage Department (DWSD), collaborative efforts to rapidly implement a SARS-CoV-2 monitoring program, analysis of SARS-CoV-2 wastewater data, and discussion on the role of the wastewater utility in wastewater surveillance. The GLWA case study has the potential to help other wastewater utilities implement programs at the local level and support the U.S. Centers for Disease Control and Prevention (CDC) efforts implementing the National Wastewater Surveillance System7. Wastewater Surveillance at GLWA The GLWA WRRF is the largest single-site treatment facility in the USA, with a primary treatment capacity of 1,700 million gallons per day (MGD). The WRRF serves the three largest counties in Michigan, including Wayne County (1.8 million residents), Oakland County (1.2 million), and Macomb County (0.8-0.9 million)8. Wastewater from residents in each county flows to three distinct interceptors: the Detroit River Interceptor (DRI, Wayne County); the Oakwood-Northwest-Wayne County Interceptor (ONWI, Oakland County); and the North Interceptor-East Arm (NIEA) (Figure 1). Therefore, wastewater surveillance analysis at these three interceptors can provide insights into public health in three subcommunities in Southeastern Michigan. From 2017 to 2019, the Xagoraraki lab at MSU worked with GLWA and DWSD to complete a National Science Foundation (NSF)-funded research grant to study viral outbreaks in Detroit via wastewater surveillance9. The research showed that measured viral signals correlated with public health data of viral disease cases and select viruses such as hepatitis A could be quantified using quantitative polymerase chain reaction (qPCR) up to two weeks before medically-reported cases. Additionally, the research allowed MSU to refine a novel sampling, viral concentration, and analysis technique with improved turnaround times compared to conventional methods. Development of SARS-CoV-2 Monitoring Program This work allowed the GLWA-MSU partnership to quickly respond to the COVID-19 pandemic. In March 2020, GLWA and CDM Smith co-funded an expansion of the previous MSU effort to focus on SARS-CoV-2 in Southeast Michigan. GLWA performed sampling at the central WRRF, CDM Smith performed collection system sampling and provided Geographic Information System (GIS) support, DWSD provided sampling and coordination support, and MSU conducted viral quantification and data analysis. All parties were involved in data analysis and research reporting. The results showed that quantification of the SARS-CoV-2 virus in wastewater was possible10. The vital work led to additional funding from the Michigan Department of Environment, Great Lakes, and Energy (EGLE) and the Michigan Department of Health and Human Services (MDHHS), with continued support from GLWA and collaboration with DWSD. Recently published results from the continued funding show that wastewater surveillance could provide early warnings of COVID-19 peaks approximately four weeks before reported cases. The program in an example of how utility seed funding and industry partnerships can springboard the development of lasting and impactful research programs at a local level. Public Health Collaboration A critical component to the program's success is active collaboration between local health departments and the GLWA, MSU, and DWSD team, necessary for data sharing and understanding. Since wastewater surveillance provides public health entities with data for informed early decision-making, the involvement of public health officials is critical for both the development and understanding of wastewater surveillance systems. As part of the 2021 surveillance work, the team held a weekly call that has led to an interactive discussion on recent results, explanatory factors, and best understanding of methods to support public health responses. Results - MSU Lab A $2.7 million MDHHS grant will support an expansion of these wastewater surveillance efforts at GLWA from 2021 through 202311, by MSU, with CDM Smith as a subcontractor and GLWA and DWSD as partners. Preliminary data from August 2020 through July 2021 show that SARS-CoV-2 were successfully measured in the three interceptors throughout the sampling period (Figure 2). Generally, the peak SARS-CoV-2 concentrations in wastewater preceded clinical cases in the community by two to four weeks12, suggesting wastewater surveillance can be used as an early warning signal for public health response. Future Considerations and the Role of the Wastewater Utility Wastewater surveillance is an effective tool to measure aggregated community-level biomarker data. Analysis of SARS-CoV-2 data in wastewater at the GLWA WRRF from August 2020 to July 2021 correlated with reported clinical cases and may provide a lead time of two to four weeks. The project's success would not be possible without thought leaders from local utilities, public health entities, industry partners, and MSU. The CDC has established the National Wastewater Surveillance System (NWSS) to increase the acceptance of the approach. Success will be dependent on successful coordination with utilities and research leaders due to their intimate knowledge of wastewater infrastructure. The results of our work can be used as a case study to be shared with the NWSS Utility Community of Practice13 for approaches to establish the network of partners required for successful integration. Capacity building will be critical to advance wastewater surveillance as a tool for monitoring and mitigating COVID-19 and future public health concerns.