It’s often referred to informally as “toilet-to-tap” technology.
And, yes, there’s an “ick” factor.
But Arizonans eventually will be drinking treated sewage – what the state Department of Environmental Quality prefers to refer to as the product of “advanced water purification” – for the simple reason that there just isn’t enough water to serve a growing population.
The work on this is well on its way. In fact, DEQ is accepting comments for the next 30 days on its plans and the standards the agency is already starting to craft.
And if all goes according to schedule, municipal and private water companies will be able to add the treated effluent to their supply by the end of 2024.
Even Robin Silver, co-founder of the Center for Biological Diversity, said it’s not a question of “if” but of “when.”
“The use of reclaimed effluent is inevitable in the arid Southwest, period,” he said. “That’s not really debatable anymore.”
More to the point, it’s already happening.
Put simply, treated effluent now is discharged onto – and in some cases injected into – the ground. And eventually it is pumped out after there has been a natural filtering process of sorts.
That’s at least part of the argument being made by DEQ.
“There’s no new water,” said Randy Matas, a deputy DEQ director. “It’s all recycled water.”
The trick now is to convince people it’s OK to bypass that natural recharge and go directly from sewage treatment plant back to homes, albeit with additional processing.
“Essentially, all this technology does is take out that environmental storage in the ground and runs this water through advanced treatment processes that actually are much more efficient at removing contaminants, pollutants than storing in the ground is,” Matas said.
Gov. Katie Hobbs already appears convinced that the rules being crafted by DEQ will provide for safe water.
“I am comfortable with science and technology ensuring that what we put into our water system is safe for users,” she said.
So, will she drink recycled water from the faucets in her home?
“Yes,” the governor responded.
And a DEQ survey conducted earlier this year found 70% said they were somewhat or very likely to drink recycled waste water.
Matas, however, said convincing all Arizonans to accept the technology will require proof that they can see.
Scottsdale already has started down that road with a demonstration project with several local breweries crafting beer with water they got from the city’s own advanced water treatment facilities. In that city’s case, that includes not just normal purification to A+ levels – good enough to discharge into streams and for irrigation – but also other processes including reverse osmosis, membrane ultrafiltration and treatment by ultraviolet light.
But Matas said the rules being crafted won’t specify exactly what methods each community needs to incorporate.
“What we’re proposing in our rule is actually establishing the treatment standards and leaving it up to the utilities to assemble the specific treatment technologies and the specific order to treat to the standards,” he said. And that will be based on the quality of the water they are starting with.
“It gives utilities and also water treatment industries the space to innovate, develop new technologies, bring those new technologies online that may increase efficiency and decrease costs as they become available,” Matas said.
Silver, however, said issues remain.
One involves “compounds of emerging concern,” including antibiotic-resistant genetic material that is getting through the wastewater treatment process. That arose in Flagstaff a decade ago when research found genetic indicators of what could be antibiotic-resistant bacteria in both potable and reclaimed water.
“That’s similar to inoculating yourself or receiving a vaccination that contributes to your body’s resistance to antibiotics,” he said. But Silver said these are not yet recognized as contaminants.
“It’s going to need to be addressed.”
But Matas said to the extent that’s a problem, it has nothing to do with whether Arizona should go ahead with advanced water purification.
“All those things are in a discharge from a traditional wastewater plant to a surface water which is then removed and treated and put into drinking water,” he said, through the normal process of filtration through the ground. “All this is doing it taking out that environmental buffer.”
And Matas said the various advanced treatment processes take out other things that now show up in water that is pumped from underground. In Arizona, that specifically includes various metals that are in the soil.
“So, you’re getting better and more complete treatment than what you would get in the natural environment,” he said.
Silver agreed this isn’t specifically a problem with direct use of treated effluent versus the current processes.
“No matter where they put it in, somebody’s going to use it,” he said.
Still, Silver said, if the state is going down the path of direct use of treated effluent – and promoting it – there are questions that need to be answered.
“We just need to assure ourselves that as we’re learning more and more about what’s in reclaimed effluent that we are removing hormonal elements, pharmacological elements and antibiotic-resistant genetic materials,” he said.
There are other issues of what can happen once the recycled water hits the system.
Consider Tucson’s experience in the 1990s when it added water from the Central Arizona Project to its groundwater supplies. The new water was more corrosive, loosening rust from inside pipes.
The least damaging part of that was brown water. The most damaging was burst pipes and hot water heaters. And it was so bad the city ended up having to bank the CAP water underground rather than feed it directly to customers.
Theoretically speaking, the situation is different here, with the super-treated water not having all those same minerals. But Matas said caution is needed.
“When you change the chemistry in the water, of course you have to consider that as far as the distribution system and corrosion control,” he said. “So these are things the utility will have to consider when they’re getting their permit for advanced water purification.”
Then there’s the question of how much this will add to each the monthly water bill.
“The cost for consumers will vary by the utility that’s putting it in place and the amount of treatment required and the size of their customer base,” Matas said.
And that DEQ survey about whether people are willing to accept recycled water also found that 71% listed the price tag as a concern.
The agency, however, is trying to address that with suggestions that some people could save money.
“Instead of relying solely on bottled water or expensive filtration systems, you can enjoy purified water at a fraction of the cost, primarily if your local water utility provides it,” the agency is saying online in its own list of questions and answers.
So, is DEQ claiming people will be able to stop buying bottled water and can turn off their filtration systems?
“Water treated through advanced water purification not only complies with and exceeds all water quality standards but offers a flavor profile akin to purified bottled water or home reserve osmosis systems,” said agency spokeswoman Alma Suarez. Still, she said “personal preferences and circumstances may vary.”
“Some people may still choose to buy bottled water or use filtration systems for convenience or specific needs,” Suarez said.
Matas, for his part, prefers to see the issue in broader terms.
“The cost of Arizona running out of water which would stall development, that would stall the economy and lead to water scarcity would drastically increase cost of living for Arizonans,” he said. “So, while this may increase your water bill, it may be the cheapest cost long term when we look at overall water security.”
There is another angle to all this that has nothing to do with water quality. It’s a question of availability.
State law says reclaimed water is the property of the entity that produces it, according to Carol Ward, an assistant director of the Department of Water Resources. And it has become more valuable, especially after the 1980 Groundwater Management Act was passed to reduce depletion.
Add to that, she said, is a 1986 law that prohibits the filling of large bodies of water for landscape, scenic or recreational purposes. That increased the demand for treated effluent – the same effluent that now communities are being urged to recycle into drinking water.
“As water becomes more expensive and supplies are more limited, that will continue to shift how water is used,” Ward said. And that will force local officials to have to make some decisions about what is the best use of the water – and whether processing it for drinking makes economic and environmental sense.
One of those decisions will have to occur in Tucson.
Much of the lower Santa Cruz River is dependent on effluent. More to the point, it also supports a wetland habitat.
The Tucson City Council voted last month to investigate the idea of supplementing its water supply with reclaimed effluent. That raised concerns by environmental interests that it would dry up the habitat.
But John Kmiec, the city’s water director, has insisted the area will be maintained.