Cost-effective wastewater-based epidemiology can extract vital health information

Water treatment plant samples contains a wealth of information

April 23, 2020

A treasure trove of information relevant to human and environmental health is hiding in an unexpected place. Samples of wastewater from homes, institutions, towns and cities around the world can now be probed for valuable data concerning community well-being, antibiotic use and resistance, recreational substance consumption and abuse, biomarkers of disease as well as environmental hazards and degradation.

This rapidly emerging health surveillance technique, termed wastewater-based epidemiology (WBE), is an economical and powerful tool. It can teach us much about large populations contributing into a centralized­­ sewerage system during the course of a full 24-hour cycle. Waste Wastewater gathered at treatment plants contains a wealth of information relevant to human and environmental health. A new technique known as wastewater-based epidemiology can extract this vital information and use it to monitor important health indices at a local or global scale. Download Full Image

In a pair of new studies, Rolf Halden, director of the ASU Biodesign Center for Environmental Health Engineering and author for the 2020 book "Environment," describes this process and highlights important new findings extracted from the municipal wastewater most of us contribute to on a daily basis. Halden is also a professor at ASU's School of Sustainable Engineering and the Built Environment.

“After being around for more than 15 years, wastewater-based epidemiology is finally getting the attention it deserves, thanks in no small part to the challenges brought about by the COVID-19 pandemic,” said Halden, a pioneer and champion of WBE whose team has built the largest single monitoring network and sample archiv­­­­e in the U.S. and around the world.

Data-rich waste

Advances in WBE technologies and applications are progressing rapidly. The method offers a low-cost strategy for obtaining health and environmental data on a local, regional, national and even continental scale. It can provide valuable information with acute spatial and temporal resolution. Because the method aggregates community-wide data, it is noninvasive and ensures the privacy of the population under study.

In addition to its ability to measure ingestion rates of drugs including cocaine and opioids, WBE has been proposed as a means of identifying exposure to agents including pesticides, personal care products, infectious pathogens, persistent organic pollutants, as well as for tracking communitywide incidence of illnesses including diabetes, allergies, stress-induced disorders and cancer.


Rolf Halden is the director of the Biodesign Center for Environmental Health Engineering. He is also a professor at ASU's School of Sustainable Engineering and the Built Environment.

In the first of two current studies, with Biodesign Institute research scientist Erin Driver as lead author, wastewater samples from a large university in the American Southwest were analyzed for the presence of caffeine, tobacco and alcohol. This study monitored the presence of these substances during the 2017-18 academic year. It is the first U.S. study to focus on these common psychotropic compounds, aimed at comparing data output from WBE to that of conventional methods, namely the use of questionnaires.

Alcohol, nicotine and caffeine use are significant public health concerns, claiming some 550,000 lives annually. Data suggest college-age students are particularly vulnerable to overconsumption of these substances, often resulting in behaviors that last their lifetimes and create poorer health outcomes. This work shows the utility of monitoring this particular subset of a population and illustrates the prospective benefit of long-term monitoring networks on college campuses to improve student health and promote future success. 

Efficient, near real-time monitoring

WBE represents an attractive alternative to communitywide monitoring through self-reported surveys, which may introduce sampling and reporting biases and are often comparatively costly to administer; how much more expensive was one of the questions investigated in the study.

In addition to measurements of the quantities of stimulants consumed, the study revealed strong positive correlations for the consumption of alcohol and nicotine as well as between nicotine and caffeine, but not between alcohol and caffeine.

Temporal information was also tracked, indicating that caffeine consumption was highest during the week, while nicotine and alcohol consumption peaked on the weekends, as anticipated. The study demonstrated the practicality and reliability of campus-wide longitudinal tracking of some 60,000 students directly and inexpensively.

In addition to monitoring health indices related to behavior, WBE could ultimately provide a low-cost means of carrying out infectious disease surveillance across populations, providing an early-warning system to alert researchers to disease outbreaks in near real time, within as little as 24 hours.

Halden hopes to leverage the power of WBE technology, ultimately combining a broad range of human health indicators present in wastewater into a comprehensive system he calls the Human Health Observatory (HHO). Currently, ASU’s HHO gathers data from over 350 cities representing around 32 million people, or roughly 10% of the U.S. population, and a quarter of a billion people globally.

Data streams

Strategies for extracting information on particular target substances vary, often using sophisticated methods such as liquid chromatography tandem mass spectroscopy, which can fingerprint chemical traces based on their differing molecular weights and characteristic ionization and fragmentation behavior. But the basic process used for WBE is simple.


Erin Driver is a researcher in the Biodesign Center for Environmental Health Engineering.

Samples of raw wastewater — sewage entering a water reclamation facility — are typically collected over a 24-hour period and then shipped to the laboratory to determine the average concentration of chemicals or their biological metabolites. The concentration value is then multiplied with the flow volume of sewage during the sampling period, to provide a more meaningful unit of a quantity of a substance per 1,000 people per day. Combining this information with estimates of average excretion rates of target metabolites permits researchers to determine the quantity of consumption of a given substance, be it cups of coffee, number of alcoholic beverages or cigarettes smoked.

The final data in the university study showed levels of alcohol consumption to be consistent with quantities observed in self-reported surveys. But whereas both study methods were shown to yield similar findings, Driver summed up the big news as follows: “In this study, use of WBE was over 200 times cheaper than conventional methods, yielding data at more frequent intervals throughout the academic year. Costs were reduced from an estimated $127 to only $0.58 per person when using wastewater analytics.”

The researchers are now measuring how the COVID-19 epidemic and the associated stay-at-home orders are impacting substance use in the university’s home city.

Health surveillance refined

In the other new study, lead authors Professors Olga Hart and Rolf Halden of the Biodesign Center for Environmental Health Engineering report on a modeling study that considered all 13,940 major sewage treatment plants in the U.S. and demographic information collected by the U.S. Census during the 2017 American Community Survey.

The aim of the study was to investigate and understand potential biases in WBE studies by examining variations in data collected due to temperature, seasonal variations and rates of biomarker decay. To do this, the researchers assumed stable consumption in the population over one calendar year and computed how the community contributing to the chemical signal detectable at a given wastewater treatment plant would change as a function of the changes induced by seasonally variable temperatures and biomarker decay rates.

The study also found intriguing correlations between seasonal temperatures and the size and distance a population can be observed by wastewater analytics. In general, during the colder months of the year the “visibility down the pipe” is better, leading to a larger population captured that resides farther away from the plant, and a more even representation of all people served by the treatment plant.


Olga Hart is a researcher in the Biodesign Center for Environmental Health Engineering.

In contrast, in-sewer degradation during the summer months reduced the observable population, and the detectable chemistry was composed primarily of communities closer to the treatment. This finding gained great significance when census data showed considerable differences in demographic indicators exist as a function of the distance of residence from a plant. Compared with the cold winter season, observations in the summer were more likely to capture households with lower income, less educational attainment, more prevalent military service, higher unemployment and greater lack of health insurance.

Hart summed up the findings:  

“If not taken into account, this uneven distribution of populations within urban environments could lead to skewed data from wastewater sampling, or to attributing to seasonal change, patterns that are actually of demographic origin. Just like in traditional human-subject studies, whether we are trying to better understand the health status of communities by passive monitoring or testing the impact of proactive interventions, it’s critical to understand if our study population significantly changes from observation to observation.”

Halden agreed and added: “This study challenges WBE researchers to reassess their data in the context of temperature changes. Regardless of whether we are monitoring chemicals or biological agents in wastewater, our research community will have to pay more attention to ambient air temperatures in order to get the most robust information from wastewater analysis.”

RELATED: Novel coronavirus detected, monitored in wastewater

Richard Harth

Science writer, Biodesign Institute at ASU


First-generation biomedical sciences grad overcomes doubts, fears to earn degree

April 23, 2020

Editor's note: This story is part of a series of profiles of notable spring 2020 graduates.

John Butler is not your typical graduating college student. John Butler, ASU Biological Sciences Graduate John Butler, a first-generation college student, husband, and father, is graduating with a BS in biological science (biomedical sciences). his goal is to become a physician's assistant. Photo courtesy John Butler Download Full Image

As a first-generation, older undergraduate who had to juggle family life, work and academic responsibilities, he learned quickly that getting support from friends and family was crucial during challenging times.

Just before he decided to go back to school, Butler faced a challenging family situation, but it’s one that helped him realize that he wanted to study biomedical sciences at Arizona State University's School of Life Sciences.

“Both of my parents passed away shortly before I decided to go back to school. It was a very difficult time but the level of care that they received, as well as the support I received during that process, particularly from the one-on-one interaction with the physician assistants, had a profound impact on me. I knew at that point, I wanted to be able to provide that for other families during their time of need,” Butler said.

He stuck with it and is a proud Sun Devil graduating this semester with a Bachelor of Science in biological sciences (biomedical sciences concentration).

Question: What is your greatest accomplishment during your college career?

A: My greatest accomplishment was being able to leave my comfort zone and to quiet the doubts, fear and hesitation that had stood in the way of me getting my degree. Everything else came from accomplishing that.

Q: What were one or two of your challenges while attending college, and how did you overcome them?

A: Being a non-traditional — ie., old guy — first-generation college student while balancing the responsibilities of family/work/academic life has been the biggest challenge. My wife and daughter have been a constant source of support and inspiration for me. Their belief in me gave me the confidence to face all of the challenges and obstacles that come with the process and stay focused on accomplishing my goal.

Q: What’s something you learned while at ASU — in the classroom or otherwise — that surprised you, that changed your perspective?

A: Being so much older than most of the students on campus, and quite frankly, most of my professors, I expected to feel a little awkward at times. But my experience at ASU been the exact opposite of that. I was very appreciative and somewhat surprised by how much encouragement and support I received from other students and the faculty. Because of that, I felt like I was a part of ASU, not just simply attending ASU.

Q: Why did you choose ASU?

A: The Biodesign Institute at ASU is leading the way in many different fields of biology and medicine and I wanted the opportunity to be able to learn from the people that are directly involved with those advances. The ability to engage with, and learn from, people at the leading edge of their field is an incredible opportunity and the School of Life Sciences here at ASU provides students exactly that.

Q: What is one of your favorite memories while attending ASU?

A: My daughter, Hannah Butler, is a microbiology major here at ASU. My favorite memories have been getting to meet up with her in between classes to grab coffee. It is such a unique opportunity that most parents don’t have, to be able to connect with your kids and bond over your shared college experience and to be able to relate to what they are doing and going through, not in hindsight, but at that moment. That has been a tremendous gift.

Q: Which professor taught you the most important lesson while at ASU?

A: Professor Damien Salamone taught me the importance of taking your education and putting it to work, to help serve your community. The outreach and volunteer opportunities I had while taking his class on HIV/AIDS really helped me see the power of education in affecting change, and the impact each one of us can make in our communities.

Q: What’s the best piece of advice you’d give to those still in school?

A: I would encourage other students to fully utilize all of the resources at the school by really engaging with their teachers as well as getting involved in some of the clubs and activities here on campus. Between work and school, it is easy to start to feel isolated, but there are so many resources on campus that can help you explore new interests, meet new people and advance your knowledge. These things really help to make you feel like part of a community and greatly improve the college experience.

Q: What was your favorite spot on campus, whether for studying, meeting friends or just thinking about life?

A: Starbucks. I’m pretty sure the Physics Department would disagree, but I am certain that the dark matter that holds the universe together is coffee.

Q: What are your plans after graduation?

A: After graduation, I will be applying to several physician’s assistant programs here in Arizona and hope to continue my education both professionally and personally.

Q: If someone gave you $40 million to solve one problem on our planet, what would you tackle?

A: I would address access to higher education in low-income and underserved communities. There is a tremendous amount of talent and potential out there that goes unrealized simply because for many kids access to higher education is out of reach. When these kids aren’t able to use those talents, we all lose. Education is more than just a means to pay your bills. It offers possibilities for enrichment in all facets of our lives and I would like to see access to those possibilities available to everyone.

Sandra Leander

Assistant Director of Media Relations, ASU Knowledge Enterprise