Since the 1990s, wastewater monitoring and analysis has provided a method to track pathogens such as norovirus and hepatitis A in a community. Studies have been conducted that test wastewater to detect drug consumption including cocaine and opioids.
In late 2020, the Centers for Disease Control and Prevention (CDC) established a wastewater surveillance network and added wastewater data to its public COVID-19 dashboard in February 2021. As recently as June 2022, polio was detected in London’s wastewater system, putting clinics on high alert for an infectious disease that has not been recorded in the United Kingdom for nearly 40 years. In fact, wastewater serves as an aggregate measure of broader health trends in a community.
Human pathogens are a major threat to global public health, and wastewater treatment plants serve as a biological equivalent of a digestive system. Pathogens are transmitted into wastewater by infected persons shedding large amounts of the pathogen in feces for days or weeks before and after onset of symptoms. The abundance and diversity of pathogenic viruses in wastewater reflect the pattern of infection in the population. It is not only possible but practical to gather and study the rich source of data that is available in wastewater.
A community interested in gathering this data needs to develop a sampling strategy that is suited for its public health needs. It should also understand that public health actions should not be based solely on the data collected from wastewater analysis. Some communities are not well-suited to wastewater monitoring; federal officials estimate one in five households concentrated in rural areas use septic systems that don’t feed into sewers or wastewater treatment plants.
The frequency of a community’s data collection will need to be determined locally, considering many factors such as sampling, testing capacity, and the availability of resources to accomplish the testing. Data gathered from the testing should be used as a part of an overall health program within the community to determine the actions needed, if any, to improve the general health of the community. The data would also need to be used in longitudinal studies to evaluate trends over the long term.
Wastewater monitoring should not only include pretreated wastewater but also the effluent to determine disinfection efficacy for these pathogens. Clearly, microorganisms are useful in wastewater treatment — especially in reducing sludge volume in wastewater treatment plants and septic tanks. However, studies have shown that some organisms have contributed to several water-borne disease epidemics. Furthermore, some pathogens can persist in sludge and treated wastewater. Wastewater treatment is crucial to environmental hygiene and confirming the effluent is free of pollutants and antibiotic resistant bacteria decreases health risk for humans, animals, and aquatic life.
Clearly, there is much information that can be gleaned from wastewater. Many U.S. communities now have programs to collect and evaluate wastewater data, which now serves as a diagnostic tool that can be used to support community health assessments. WW
Published in WaterWorld magazine, November 2022.
