Drinking wastewater? It’s an option whose time has come, says Colorado Springs Utilities | Local News


Kirk Olds, Colorado Springs Utilities’ manager of water engineering/project management, briefs the media in front of the trailer containing a water reuse apparatus.

First, you have to get past the “ugh” factor.

“It’s a real thing,” Tara Kelley, manager of wastewater treatment for Colorado Springs Utilities, admits.

That “ugh factor” comes when offered a swig of recycled wastewater that promises to be part of the city’s future — satisfying customers’ water needs in a time of climate change, dwindling water supplies and competing uses.

While other countries and San Diego, California, have long used water from recycled sewage water for domestic purposes, it’s a new thing in Colorado, which has yet to develop and adopt regulations for “direct potable water reuse.”

On Aug. 3, Springs Utilities invited the media to hear about an experimental project in which the utility cooperated with the Colorado School of Mines and Carollo Engineers to develop a mobile unit containing a 5-gallons-per-minute apparatus. It’s currently staged at the J.D. Phillips Water Resource Recovery Facility on Mark Dabling Boulevard.

As the population grows and the planet heats up — a decades-long drought has drastically reduced water in Lake Mead and Lake Powell reservoirs — a solution must be found to offset depleted supplies from the Colorado River. The river, source of 65 percent of Colorado Springs Utilities’ supply, has been over-appropriated, meaning those owning water rights to it will face shortages.

That’s why Utilities is eying reusing water for integration into its Sustainable Water Plan, though officials couldn’t say when its customers might start drinking direct reused potable water.

While Utilities saw water demand drop by 9 percent in July due to rainfall, it’s not a dependable strategy to look to the skies and hope for more rain in the summer and snow in the winter to fill reservoirs that feed customers’ taps, says Utilities spokesperson Jennifer Kemp.

“We like to have all these tools in our tool belt,” Kemp says. “It gives flexibility when our sources might be strained.”

Most of Colorado Springs’ water supply comes from outside native basins, such as the Colorado River, for which the city has rights for use to extinction. That means it can be reused multiple times, unlike native water, like from the Pikes Peak system, that can only be used by the city once before it must be released for other users through Fountain Creek and other channels.

Kirk Olds, Utilities’ manager of water engineering/project management, says the city has successfully used nonpotable water for irrigation for decades and could expand that system. But there’s a point at which it’s no longer economical to build that system, he says.

Also, the city already reuses water through “exchanges,” a complicated system in which water is traded with other users for other water rights.

No water provider in the state reuses direct potable water using the new system to treat wastewater, previously treated to a discharge standard, for human consumption.

Olds says it’s not yet clear how much a direct potable water system would cost to handle a significant portion of the millions of gallons a day delivered in Colorado Springs, because there are too many factors that play into the cost. However, it’s a concept worth further study and investment in the demonstration project, which was several years in the making.

As the scale is increased for volume, the cost diminishes, he says, unlike extending nonpotable systems and conveyance lines, for which the price increases as scale increases.

“We know as we go into the future, we need to reuse our water supply,” Olds says. “With climate variability and competing uses in Colorado, we’re always looking for ways to be more effective and efficient with water use.”

Competing uses include domestic, agricultural and recreational usage.

“It’s not a new water supply, but it’s another way we can use the water supply designated for that purpose [various classes of usage],” he says. “Recycling water in this fashion gives us another local source.”

Funded with a $350,000 Colorado Water Conservation Board grant to advance the state’s 2016 Colorado Water Plan, the demonstration project is called Purewater Colorado and is termed a “state of the art non-membrane treatment system.”

purewater interior

Utilities’ Kirk Olds checks the readings inside the mobile unit that turns treated sewage water into drinkable water.

Here’s how it works:

Water is pumped from a water treatment plant into a system that injects ozone gas into the water, which degrades organic matter and breaks down it into dissolved oxygen. This process destroys microorganisms and breaks down trace chemicals.

Next, the water passes through biologically activated carbon filters covered with “aerobic” bacteria, which thrive on the presence of oxygen. This process consumes organic matter and removes trace chemicals.

Step three is called microfiltration. Water is pushed through tiny pores in a ceramic membrane to remove microscopic particles, including suspended solids, bacteria and protozoa.

After that, the water flows through carbon granules to remove trace chemicals and organic matter.

Advanced oxidation then takes over. The process generates high energy UVC light, creating a process that produces high energy radicals, which damages the DNA of any microbes or viruses, robbing them of the ability to replicate.

Finally, chlorination adds chlorine to further inactivate pathogens, and a residual disinfectant ensures water is safe to drink. The water is tested to be sure it meets all the standards for human consumption.

Olds says the Purewater project promises to allow the city to reuse water at least once and perhaps more often.

The carbon-based system sucks up much less water than other methods, such as reverse osmosis, which can drink up to 20 percent of the water that’s being prepared for reuse.

Christopher Bellona, associate professor of Civil & Environmental Engineering at Colorado School of Mines, says he’s been working on direct potable water use since he was a graduate student in 2001. Now, 20 years later, he’s part of the team that put together what he had labeled a “pipe dream” — the Purewater project.

He foresees reuse will be “an integral part of supply management” in the era of climate change, population growth and diminishing supplies.

Olds promises “no discernable difference” in look or taste “from what comes out of the tap today.”

Asked if Springs Utilities customers will be told when reused water is flowing through pipes to their homes, Olds says yes.

“We’re telling the story today,” he says, noting there will be “full disclosure” if and when Purewater is scaled to the size to feed the reused water into the city’s pipes.

“When this happens, it will not be a surprise,” he adds.

If questions arise about whether this will rescue Utilities customers from conservation measures, the answer is no. 

Pat Wells, Utilities’ general manager of water supply and demand management, says, “Water use efficiency goes hand in hand with reuse.”

He predicts the city will continue finding ways for its customers to use water more efficiently and build in certain curtailments in the development rules used by both the city and El Paso County, as well as building codes that call for more efficient appliances indoors.

Asked about the downsides of the Purewater system and ones like it that might emerge for broad, large-scale use, Wells says water reuse is superior to losses experienced by using a traditional system of non-reuse, such as through evaporation, transit and legislated reductions to certain users as supplies dwindle and more calls are made on river systems.

But he does mention two concerns: the cost of new systems, which hasn’t been priced out yet, and “public acceptance.”

Drinking vessels

Can you tell the difference between first-use water and water that’s been recycled from treated sewage?

Which brings us to the taste test Utilities set up at the news conference for those on hand to try for themselves.

One tank was labeled “current drinking water,” another, “purified drinking water.”

The latter had no discernible difference in look or taste to the normal tap water.

But, hey. Don’t take our word for it. Sign up for your own taste and tour of the mobile Purewater unit here.

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