ReWa testing for SARS-CoV-2 in wastewater

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Renewable Water Resources (ReWa), the non-profit entity responsible for providing regional wastewater treatment and collection services in and around Greenville County, announced that they voluntarily and proactively began a program in early June to test SARS-CoV-2 levels in our area’s wastewater and will continue testing through the end of the year. SARS-CoV-2 is the virus that causes COVID-19. The agency’s goal in this initiative is to provide scientifically sound, valid, longitudinal data that can help drive more informed decisions and improve community health and safety.

ReWa collects samples twice a week from its Mauldin Road treatment facility, its largest plant which serves the bulk of the greater Greenville area, and sends them to a nationally recognized biological testing lab, which generates reports for ReWa with a one-week lag time between collection and reporting. The data is then shared with the environmental engineering department at Clemson University, led by Dr. Michael Freedman, for comparison, validation and analysis. Freedman’s team is working on a similar testing initiative. ReWa, which does not interpret or analyze its own data, has also made this information available to other universities, as well as governmental, environmental and regulatory agencies to help inform policy decisions.

Findings and Timing

Eighteen samples have been taken in total and sent to Clemson University’s Department of Environmental Engineering. Freedman’s analysis of the data shows that each of the samples indicate consistent “significant” to “major” levels of COVID-19 infection in the general population of Greenville County.

According to Freedman, as long as the levels of the virus remain under 100,000 copies per liter, there should be little to no community concern. However, anything between 4,000 and 10,000 suggests to scientists that something big is about to happen. There is generally a two-week lag time between the higher levels found in wastewater and an increase in infection, potentially giving leaders time to prepare for an outbreak. By June, ReWa’s wastewater readings at Mauldin Road rose to 310,000 copies per liter and have stayed above 100,000 since. Four separate readings have shown levels reaching above 1 million copies per liter, including, most recently, on July 20.

The First Part of the Curve

While it is still early in the testing process, ReWa’s data may be a reliable indicator of trends over time, including spikes and increasing or decreasing rates of infection. The data can also be correlated to determine events that may cause spikes, such as holidays or the effect different approaches (such as requiring masks or increasing/reducing seating capacity in restaurants) may have on infection rates. The data can also be used to predict coming surges up to two weeks in advance.

It is important to note that while wastewater epidemiology has been used for years to study other illnesses, COVID-19 is very new, so tactics must consistently be evaluated and re-examined. In keeping with its long tradition of community stewardship, innovation and scientific rigor, ReWa is an early adopter of these testing protocols and must rely on experts to interpret and analyze the data.

“Since we’ve only seen the front half of this curve, to a certain degree, we must learn along the way,” said Chad Lawson, ReWa’s spokesman. “We are in completely new territory, so it’s a discovery process that’s transparent and in the public space. Normally, research data is fully vetted and peer reviewed before publishing, but ReWa has chosen to make this data available for interpretation now in the interest of serving our community.”

It is also important to note that ReWa will not use its data to advocate for any specific policy decisions. Rather, the agency simply hopes to offer additional insight and information to those responsible for making such choices.

Safety First

While the virus can currently be found in our wastewater, it is important for area residents to know our water supply is safe. Wastewater treatment systems have always been critical in protecting the community from a variety of viruses, bacteria and other organisms which can cause illness, so ReWa’s treatment facilities follow stringent standards to protect waterways and ensure community health. In fact, the treatment processes used by ReWa meet and exceed State and Federal regulatory requirements. Each treatment facility uses either ultraviolet radiation (UV) or chemical disinfection with hypochlorite to deactivate viruses, such as SARS-CoV-2, and other potentially harmful organisms to ensure that treated water is safe to return to surrounding waterways.

As a long-standing and continually active member of organizations like the Water Environment Federation and the Water Research Foundation, ReWa is at the forefront of international efforts to study COVID-19 and advance wastewater epidemiological efforts in the future.

“The COVID-19 situation gives us an opportunity to demonstrate what ReWa has known all along: Wastewater treatment is a public health issue of the highest order,” noted ReWa Chief Special Projects Officer Rebecca West. “What we do now in terms of wastewater epidemiology and research matters a great deal, not just in fighting COVID-19 but in our ability to be more prepared and proactive if and when future outbreaks occur. ReWa has always been a leader and a vanguard in our industry, and we are proud to use our scientific expertise to help address this public health crisis quickly, effectively and in a non-partisan manner.”

For more information on Clemson’s interpretation of area data, please visit: https://www.clemsoncity.org/Activityfeed/Myarticles/TabId/197/ArtMID/2433/ArticleID/3946/Clemson-University-SARS-CoV-2-in-Wastewater-Monitoring-Record-Updates-August-4th.aspx

About Renewable Water Resources (ReWa)

Since 1925, Renewable Water Resources (ReWa) has been committed to providing high-quality wastewater treatment services to the Upstate of South Carolina while promoting a cleaner environment, protecting the public health and water quality of the Upstate waterways and developing the necessary sewer infrastructure to sustain our community and growing economy.

With nine water resource recovery facilities and more than 350 miles of pipe, we serve a broad geographic area, including Greenville County and portions of Anderson, Laurens, Pickens, and Spartanburg Counties up to the North Carolina border. Each day an estimated 42 million gallons of water passes through our trunk lines and reclamation facilities before being cleaned and returned to our area rivers and streams. To learn more about ReWa, please visit www.rewaonline.org.