Antibiotic Resistance in Wastewater Studied in Flagstaff, Arizona

Recycled wastewater is used to water the grounds of Northern Arizona University.

Recycled wastewater is used to water the grounds of Northern Arizona University.

The city of Flagstaff, Arizona, has announced it is working on three research projects to address concerns about antibiotic-resistant bacteria in its reclaimed wastewater.

According to the Arizona Daily Sun, the three projects address antibiotic-resistant bacteria, their presence in recycled wastewater, and their impact on human health.

The research is being led by members of the municipality’s Compounds of Emerging Concern Advisory Panel, which includes researchers from the University of Arizona and Virginia Tech, as well as local physicians and government officials.

Flagstaff’s wastewater is treated in multiple stages, which include UV treatment and the addition of bleach, before it is distributed to irrigate local golf courses, the grounds of city schools such as Northern Arizona University, and municipal parks.

Antibiotic Resistance Concerns

The city of Flagstaff was compelled to study the matter after Robin Silver, a local physician, and other residents presented their concerns. A 2012 study coordinated by Amy Pruden, a Virginia Tech researcher, found Flagstaff’s reclaimed water system may be a breeding ground for antibiotic-resistant bacteria; however, opinions diverge as to whether the bacteria could ultimately harm residents.

Neither the state of Arizona nor the United States Environmental Protection Agency regulates antibiotic-resistance genes in water. So-called “compounds of emerging concern” cover a wide range of compounds not regulated by the EPA, which also include prescription drugs, personal-care products, and other substances that may enter wastewater treatment systems through conventional use.

Studies’ Focus

Because there is so little research on antibiotic-resistance genes and antibiotic-resistant bacteria in reclaimed water, the panel is focusing its efforts on those subjects. Whether antibiotic-resistance genes can ultimately be transmitted into bacteria that can spread disease to people via wastewater is one answer that “every municipality wants to know,” said Jean McLain, associate director of the University of Arizona’s Arizona Water Resources Research Center and a member of the advisory panel.

Some of the work will be funded by the National Science Foundation and the Water Environment Research Foundation, while the Translational Genomics Research Institute North (TGen North), a local genomic and pathogen research laboratory, is contributing its resources to perform DNA sequencing analysis on city water samples.

One of the studies, to be undertaken by University of Arizona and University of Nevada, Las Vegas, researchers, is focusing on possible water treatment modifications. They will determine processes able to prevent antibiotic-resistant bacteria from moving through the environment.

Recycled Wastewater Quality

The City of Flagstaff also announced in September that its Wildcat Hill Wastewater Treatment and Rio de Flag Reclamation plants have been producing water meeting the Arizona Department of Environmental Quality standards for A+ reclaimed wastewater for the last 10 months. The local government had invested $2.13 million on repairs and testing to reach consistent A+ reclaimed wastewater for its customers. As much as 6 million gallons a day are produced by the facilities. The water is used for irrigation, snowmaking in winter, and by local industrial customers.

At least two of the expenditures were on studies that might require additional investments. One study may indicate the need for future equipment upgrades. Another study, designed to determine which  industrial chemicals are being discharged in the municipal wastewater system, may require system improvements to better treat the chemicals entering the wastewater. The findings will be used to assess wastewater quality limits by industry.

These research projects are critical to the city, which recycles more than 700 million gallons of water each year. However, they are also key to resolving opposition to water reuse throughout the United States. Many government officials say the practice is too new and there are too many unknown factors associated with water reuse, including whether trace contaminants can accumulate in the environment and in the groundwater.

Image by 5u5, used under a Creative Commons Attribution 2.0 Generic (CC BY 2.0) license.