Potable Recycling in Colorado

I don’t usually re-post articles straight from newspapers here. However, I thought some readers might find this one from the Denver Post interesting.

Notable is the fact that the city planners, the water authorities and the Colorado Department of Public Health and Environment are all keen to promote what we would call an ‘unplanned’ or ‘incidental’ potable water recycling scheme. In Australia, some State Governments would play it down or pretend not to notice. Some community members call it ‘bad practice’ and would have you believe that US agencies are opposed to it.

Tapping used water
By Jeremy P. Meyer
Denver Post, 23 January 2007.

The city of Aurora is working on a $754 million project to extract water from the South Platte River, treat it and pipe it to customers - a process that will increase Aurora's water supply by 20 percent.

Snowmelt running down mountainsides and into reservoirs has been Aurora's main source of drinking water - as it has been for other Front Range cities.

In three years, residents of the Denver metro area's second-largest municipality will get recycled water out of their taps.

The city's $754 million Prairie Waters Project will draw South Platte River water downstream from the Denver Metro Wastewater Reclamation District's plant.

The river water will be sent through sand and charcoal filters, treated with chemicals and zapped with ultraviolet light.

"This is the wave of the future," said Glenn Bodnar, drinking-water specialist for the Colorado Department of Public Health and Environment.

"The way Colorado is growing and the finite amount of pure water we have, water systems are going to be looking for additional sources of drinking water," Bodnar said. "Aurora is leading the charge."

The water will be pulled from the river near Brighton, sent 34 miles south to Aurora, treated in the 40-day, six-step process, and ultimately blended with the mountain water.

Prairie Waters was created when the city faced the risk of running out of water in 2003 after a persistent drought.

Lack of snowfall and rain in the mountains left Aurora's reservoirs with only a couple of months' supply as the summer season approached.

Aurora Water director Peter Binney, who had been in the job for a year, said he never wanted to go through that kind of a crisis again.

"You don't want to be running a large water system with that kind of vulnerability," Binney said.

(Click to enlarge)

Deals with farmers were arranged for their water rights, and the city looked at 54 plans to get more water to the city.

Prairie Waters - the first large-scale water-reuse project in Colorado and the state's first big water project in 40 years - became the No. 1 choice.

"It's really setting up a water machine that is as close to a perpetual-motion machine as you can get," Binney said.

While the system of diverting mountain water to the Front Range has allowed eastern Colorado to prosper, it also has pitted the Western Slope against the Front Range, farmers against city dwellers, and water managers against environmentalists.

The reuse approach of Prairie Waters, some say, is one way to broker peace in the water wars.

"It's an approach no one has taken in Colorado," said Aurora Mayor Ed Tauer. "We've spent in this state decades fighting about water."

Environmental groups are still scrutinizing Prairie Waters but have given their initial approval.

"This is a progressive way to meet new water needs," said Bart Miller, water program manager for Western Resource Advocates. "We're very encouraged because of what it's not doing - another transmountain diversion."

The project is slated to be completed in 2010, boosting the city's water supply by 20 percent.

The city's 300,000 customers are already picking up the tab, paying an average of 12 percent more on their bills this year and an additional 12 percent next year.

Tap fees have risen from $6,711 per home to $16,641. Aurora also plans to sell bonds later this year for the project.

"The one downside is the project will be expensive," Tauer said. "But it will be cheaper to do it now than in 20 years."

In drought years, junior water users downstream - particularly farmers and others with wells - may be forced to leave fields fallow if Aurora uses all of its 10,000 acre-feet in the Prairie Waters system, Binney said. An acre-foot, which is the amount of water that would cover one acre to a depth of one foot, is generally believed to be enough to serve the needs of two families of four for a year.

The quality of the drinking water will also remain a challenge.

"The water that they will begin with will be of lesser quality than what we divert or what Aurora diverts," said Chips Barry, manager of Denver Water, the state's largest water company. "Now, it hasn't been through someone else's kidneys. They will have to do more advanced treatment than if it were pure snowmelt."

That is the reason Aurora is using a six-step process, when only two steps are needed to meet state and federal drinking- water standards, city officials say.

The goal is to make the reused water indistinguishable from the current supply.

Aurora's water currently has a total dissolved-solids concentration of 200 parts per million.

Officials want Prairie Waters to produce water with a maximum of 400 parts per million TDS concentration - which they say cannot be detected.

"They are setting a precedent," said Bodnar. "If cities want to continue to grow, and people are still looking for water to serve those additional folks, we're going to have to be creative. This sets the bar."