The East Bay Municipal Utility District (EBMUD) is a not-for-profit public agency established in 1923 under the Municipal Utility District Act. EBMUD has a proud history of providing high-quality drinking water for 1.4 million customers in Alameda and Contra Costa counties in the San Francisco Bay Area. EBMUD’s wastewater treatment serves 685,000 customers and protects the San Francisco Bay.
By Eileen White, Director of Wastewater, East Bay Municipal Utility District
EBMUD working on pilot effort of testing sewage to monitor for infection
Wastewater is a potentially useful resource for cost effectively monitoring the COVID-19 outbreak. The coronavirus is shed in stool and can be detected in wastewater. Researchers around the world are launching various investigations to sample and analyze wastewater for SARS-CoV-2, the novel coronavirus responsible for COVID-19. Individuals infected with COVID-19, both asymptomatic and symptomatic, shed the virus in bodily excretions that make their way to the sewage system where the genetic material can be extracted and measured. It is not clear whether the virus contained in stool is infectious or not; however, it can be quantified and used to understand the prevalence of the disease in the community. The testing of wastewater to ascertain the presence of items in the community, like microbes or drugs, is called Wastewater-Based Epidemiology.
By testing raw (influent) wastewater, we can monitor trends in real-time, evaluate community infection rates, prioritize focus areas, and theoretically observe the impacts of shelter-in-place orders. Monitoring SARS-CoV-2 in wastewater can provide public health and medical professionals with a leading indicator of anticipated infection dynamics versus the lagging indicator of case counts (i.e., negative tests, positive tests, hospitalizations, or mortality). It can also assist in targeting early population testing and inform public health measures to ensure efficient regional and state responses, such as quarantining and overall supply and resource distribution for items such as face masks and medical supplies.
The unfortunate reality is that no vaccine is currently available to protect against COVID-19 and there are not enough tests to assess the precise prevalence of COVID-19 in the community. Wastewater surveillance offers a promising approach for monitoring and predicting this public health crisis. By taking just one draw of raw wastewater, we can understand the prevalence of COVID-19 among tens of thousands of people in EBMUD’s service area.
We know that the virus is present in wastewater where there are infected people, and we have the analytical tools to find and quantify the virus. However, there is still work to be done to develop robust methods that provide reliable, reproducible data. We need to be cautious and first confirm that the numbers reported by the labs are representative of the actual amount of virus present in the sampled wastewater. Next, we need to better understand virus shedding rates and the variable characteristics of wastewater to establish the correlation between the virus concentration and the number of infected individuals in the population. Even if we are not able to determine the precise community prevalence, this tool can still be utilized to monitor the change within a certain collection point.
To further this monitoring effort, EBMUD has been collecting wastewater samples along with neighboring San Francisco Bay Area utilities and collaborating with several universities to develop analytical methods. Specifically, EBMUD is partnering with University of California at Berkeley, Stanford University, and other universities to develop a regional monitoring program. EBMUD has contributed weekly samples since mid-March and will continue to work closely with partners as the study expands to include agencies in other parts of California and the United States. The district is also providing wastewater influent samples to the University of South Carolina, which is collaborating with the Centers for Disease Control and Prevention to study exposure of wastewater workers, which may help inform EBMUD practices.
To increase testing capability, EBMUD will begin testing wastewater for SARS-CoV-2 at our Main Wastewater Treatment Plant laboratory. The presence of coronavirus in wastewater presents a remarkable opportunity to track the spread of the virus throughout the community over time and across different geography. Taking one sample of wastewater before it enters the treatment plant can provide information about a population of 685,000. EBMUD is currently sampling from flow into the MWWTP. Additional sampling could be conducted further upstream in the collection system to better understand the variability in virus concentration geographically. EBMUD may increase sampling within its service area, including parts of Oakland, Berkeley, Albany, Alameda or other cities, to evaluate the presence of COVID-19 within the community.
Through this regional collaboration with wastewater utilities, public health officials, and academic researchers, we hope to create a model for other regions, the state, and the nation. There is a critical need for funding and federal coordination in order to effectively implement Wastewater-Based Epidemiology throughout the country. A coordinated effort is essential to establishing standard testing methods, increasing lab capacity, and implementing consistency in interpreting lab results and providing timely notifications. Wastewater-Based Epidemiology is a valuable tool to inform community, state, and federal policies that mitigate impacts from COVID-19 and support medical efforts to protect public health.