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Reclaimed wastewater faces new scrutiny

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Rethinking reclaimed redux

Following a new report, scientists call for the city of Flagstaff to dig deeper into possible adverse health effects of reclaimed wastewater. (Jake Bacon/Arizona Daily Sun/file)

The water Flagstaff folks send down the kitchen sink and the toilet ultimately ends up at one of two sewage treatment plants in Flagstaff.

The toilet paper and "solids" are screened out, bacteria are put to work on the waste, then the waste and water are further filtered and blasted with ultraviolet light to kill what survives.

Just as the "reclaimed water" leaves the plant, a shot of industrial-grade bleach is added to ensure no gunk will grow in the purple pipes that carry the water out to golf courses, Northern Arizona University landscaping and municipal parks.

But a new and first-of-its-kind study of Flagstaff's treated effluent by a noted Virginia Tech scientist suggests that maybe an altered bacteria is growing in those purple pipes -- and researchers hold different opinions on whether that's true and what it signifies for the public.

On one hand are concerns that normal bacteria living in the city's reclaimed water system, and in its ponds and streams, are acquiring the ingredients they need to become resistant to antibiotics.

That's a concern for some researchers because they raise questions about the impact this might have on other living things, including people, in the environment.

On the other hand are researchers raising doubts about whether this is significant -- whether this is or ever could be nearly as big a health problem as patients prescribed antibiotics for years, or people touching drug-resistant bacteria commonly found on raw meat.

The one thing the Ph.D.s do mostly agree on, though, is that the city of Flagstaff should seek more research on this water used in public parks, softball fields and destined for making snow.

The city of Flagstaff is considering doing that, by forming an advisory panel that would outline what the city should investigate. Depending on the findings, the next step might be to develop new standards -- up to and including removal -- for environmental contaminants not currently covered by state or federal law, and to examine what it would cost to treat sewage to that level.


A brief look at what vaccines do is a good way to describe what researchers are discussing with this August report.

It analyzed reclaimed wastewater from Thorpe Park, Bushmaster Park, Coconino High School, Foxglenn Park, Wheeler Park and the taps outside the sewage treatment plants.

Someone receiving a vaccine gets a weakened form of a disease added to their body, frequently via injection or nasal passages.

The body takes the weakened disease germs, recognizes them as foreign invaders and makes antibodies to fight the foreign germs.

If the vaccinated person is later exposed to the germs from someone ill, in the form of highly contagious measles for example, the antibodies attack the foreign germs and usually win.

Antibiotic-resistance poses a similar sort of idea, but in a less happy direction for humans -- sort of like an anti-vaccine.

So, what if you could pick up and multiply germs that would prevent your body from using antibiotics to fight a major infection, because these germs were resistant to drugs?

That can and does happen all the time, researchers very broadly agree.

It's a worrying enough issue for groups like the Union of Concerned Scientists that they have asked Congress to tighten laws on when antibiotics can be used.

Antibiotics can stop working for some patients when people take them long term, don't take them in the prescribed manner, or when people are exposed to animals that were fed antibiotics long term in commercial ranching operations (and raw meat from these animals).

This becomes a serious matter in the case of a bad infection, and a patient depending on a strong antibiotic to stop it.

The matter in Flagstaff's reclaimed water, though, is a couple steps removed from all of this.

What if the water system had the ingredients to make antibiotic-resistant germs, but not proof of real, living germs?

Could our reclaimed water system become a petri dish producing bacteria carrying some ingredients that people don't generally want in their bodies?


Amy Pruden is an associate professor of civil and environmental engineering at Virginia Tech, and leader of the study looking at Flagstaff's water.

The material found in the reclaimed wastewater samples sometimes miles downstream of the Rio de Flag sewage treatment plant include resistance genes at levels greater than in water unaffected by humans.

One of the resistance genes is not commonly found in soil or water and allows bacteria to survive vancomycin treatment, which is a last-resort antibiotic used to save human life.

Here's what Pruden says about her findings when it comes to human health:

"There is not immediate cause for alarm because this study did not examine any specific bacteria that cause disease. It could be that all of the bacteria detected in this study, like most bacteria, are harmless to humans. Further studies are recommended to see if any known disease-causing bacteria are present," she wrote.

The concern is that some bacteria carrying antibiotic-resistant genes can share those genes with many other bacteria, creating a sort of incubator for drug resistance.

People could be affected if infected with the bacteria on the skin or elsewhere Pruden hypothesizes, though she says that's really a matter for epidemiologists to research.

Really this opens the door to other questions, she thinks.

"The bigger concern is not specific to the reclaimed water in Flagstaff, but is a larger global concern as more and more communities worldwide are turning to water re-use to save water ... Several studies around the world have shown that antibiotic-resistant bacteria, including pathogens, survive and sometimes even thrive in wastewater treatment plants. More research is needed on reclaimed water systems to determine what risks they may pose, if any, to increasing background levels of resistance and ultimately the number of people that become ill with infections that cannot be treated with antibiotics," Pruden wrote.


Lance Price is a microbiologist and director of a local center for microbiomics and human health at the northern brand of the Translational Genomics Research Institute.

He studies fungi and bacteria that live in people's sinuses, ears and genitalia, and has also looked greatly into the ways people become resistant to most or all of the antibiotics used to fight bacterial infections.

Here's what he thinks:

"You know that I am very concerned about antibiotic resistance and the overuse/misuse of antibiotics; however, these data are too preliminary to be useful for evaluating potential risk," he wrote.

He references things called "biofilms," which are collections of bacteria that can form a film -- like that film on your shower door or curtain.

"The existence of these genes in partially treated wastewater is not surprising. The idea that there may be amplification of resistance genes among the bacterial that form biofilms in the purple pipes is also not surprising. The important question, which is not addressed in this study, is: what bacteria are carrying these genes? Are there viable antibiotic-resistant bacterial pathogens in those pipes and in that water? Thus, I agree with their conclusions that these results warrant further studies aimed at quantifying and characterizing the living bacteria that may be carrying these genes in the "purple pipes." We certainly don't want to be spraying parks, playgrounds or ski areas with (drug-resistant staph) and (vancomycin-resistant bacteria)."

Biologist Paul Keim, who studies dangerous pathogens like anthrax at the Translational Genomics Research Institute, says exposure is the key.

"There are large international studies that have identified the real threats to antibiotics as therapeutic agents. These involve the misuse of these drugs in 1) animal food production and by 2) physicians in medical practice. In both cases, humans are forcing the evolution of new pathogens with multi-drug resistance phenotypes," he wrote.

Other researchers had other points of view (see related story).


The city of Flagstaff has drafted talking points on the matter, after physician Robin Silver and others raised it.

"We understand that studying antibiotic-resistant genes in reclaimed water both at the local and national levels is very early on in its research development. We also understand from this study that no quantitative health risk conclusions can be drawn from this limited information," the city wrote.

The city states that Arizona regulations are silent on the kinds of elements found in this research, which is accurate -- nor are they regulated by the U.S. Environmental Protection Agency.

City Manager Kevin Burke proposes to convene an advisory panel to develop a plan to study particulates detected in untreated water, drinking water and reclaimed water and, based on the results on any study, what to do next. For now, there are no immediate plans to alter the ways in which reclaimed wastewater is distributed and applied throughout the city.

Cyndy Cole can be reached at or at 913-8607.


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