by Michael L. Walker, PE, CEM, LEED-AP
Vice President, Energy and Environmental Services
Testing wastewater for the presence of pathogens as a surveillance tool has been used by for many years (Poliovirus and antimicrobial resistance (AMR) as an example). This public health tool is now being utilized during the current pandemic to detect SARS-CoV-2 (COVID-19) by analyzing wastewater samples from public and private wastewater systems for non-infective RNA fragments of the virus. Currently, research and surveillance studies are being conducted in Milan, Spain, Australia, the Netherlands, France, Germany, New Zealand, and the United States. In fact, in the U.S., more than 170 wastewater facilities across 37 states are being tested.
Studies have shown that this type of environmental sampling can be used for early detection in a population days before symptoms are observed or clinical testing is conducted, thereby preventing widespread transmission of COVID-19.
Recent articles in various news outlets describe a success story at the University of Arizona. All students were required to have a COVID-19 test taken prior to stepping foot on campus. Additionally, as students were returning, the University embarked on a program to regularly screen sewage from each dormitory building. When a wastewater sample from one dorm came back positive this week, the school quickly tested all 311 people who live and work there and found two asymptomatic students who had tested positive. Once identified, the University was able to conduct a contact tracing assessment and isolate not only those two students, but also those who may have been in contact with them.
“What we really need to find out are who are the people who are asymptomatic that are positive, so this random testing, this use of wastewater-based epidemiology is going to be really important, as well as watching the compliance metrics of how many people are covering their face, how many people are downloading the app for contact tracing, how many people are completing their daily wellness check?” University President Robert C. Robbins said in a news conference on August 27, 2020.
“With this early detection, we jumped on it right away, tested those youngsters and got them the appropriate isolation where they needed to be,” said Richard Carmona, a former U.S. surgeon general who’s now the University’s reentry task-force leader.
Obviously, simply analyzing combined wastewater for RNA fragments at the headworks of a typical Publicly Owned Treatment Works (POTW) will not provide useful and timely information to public officials. Systematic sampling of trunk lines, upgradient of the treatment plant, will be necessary to isolate areas from where the RNA fragments are being introduced to the wastewater. Since the analysis can be conducted rather quickly, public health officials can take action to screen the population in question and isolate those who are infected.
The Centers for Disease Control (CDC) has established a National Wastewater Surveillance System (NWSS) to act as a repository of current research and public health program results in an effort to further support public health officials effectively identify infections and prevent potential outbreaks.
If you have any questions regarding wasterwater sampling or other COVID-19 related professional services, please contact Mike Walker at (919) 459-5245 or mwalker@ei1.com.