How Wastewater Treatment Plants are Used to Monitor Public Health?

There are more than 16,000 wastewater treatment plants or WWTP’s in the US treating wastewater generated by more than 75% of the population.  Most every urban area with a population of 50,000 or more residents uses at least one WWTP to treat wastewater.  When most of our population flushes the toilet, brushes their teeth, or washes dishes in a sink, they generate wastewater that requires treatment.  This wastewater flows through pipes to trunk lines under the streets, is often collected in tunnels hundreds of feet below ground and is then pumped to the surface for treatment in a WWTP during the night when wastewater flows are the lowest.  [See “How Tunnel Construction Solved Sewer Overflows in Many Older US Cities”, posted 7/5/23].

Most of us envision no use for wastewater.  However, sociologists observe much can be learned about a society based upon what they throw away.  Such observations have equal application to wastewater upon its arrival at our nations WWTP’s.  Cities have long since monitored wastewater to identify the illegal release of “hazardous waste” and then track such materials back to the point of discharge and responsible generators.  Other Cities monitor the volume of “pharmaceuticals” flushed away by residents to dispose of unused prescription medications that are no longer needed. Such substances are monitored for proper operation of the WWTP to investigate and manage the impacts chemicals and drugs may have upon the anaerobic bacteria that are critical to the treatment of wastewater.  Within the last 30 years, Cities have begun to monitor wastewater for purposes other than operation of the WWTP, namely to monitor and investigate public health.

In recent years, an entire science has developed around the monitoring of wastewater to investigate public health, known as  wastewater-based epidemiology (“WBE”) or “sewershed surveillance”.  WBE has been used to monitor a variety of pathogens, including viruses, anti-biotic resistant bacteria, and most recently the outbreaks and mutations during the COVID-19 pandemic.  Researchers now believe WBE may be used to monitor other diseases, including “enteroviruses" (such as polio), "orthopox" viruses (such as monkeypox), and other "emerging pathogen threats”.

 The data collected by WBE has traditionally been used for 3 central purposes.  First, to monitor and investigate the volume of pathogens and infection rates within a community.  Second, tracking mutations and other trends taken by the pathogens in their quest to avoid eradication.  Third, to focus treatments upon a neighborhood or targeted site so testing and treatment can focus upon “hot spots”.  Recently, a fourth use has arisen.  Faced with the explosion of unmonitored immigration, sanctuary cities are now seeking to track and trace the recurrence of pathogens previously eradicated but now reappearing. 

WBE has proven so instrumental to monitor public health, that the Centers for Disease Control or CDC developed the "National Wastewater Surveillance System" or NWSS.  This new federal agency is responsible to coordinate, create, and maintain our nations capacity to track the presence of pathogens in WWTP’s throughout the US.  As it turns out, both science and medicine have discovered wastwater can provide mountains of information and useful data about the populace by which it was produced.  Wastewater is nowhere near as useless as many believe it to be.