Seeking Water from the Sun

Providing water purification solutions in arid lands

Tim Vanderpool

The Navajo Nation is awash in stunning vistas, from sun-bathed plains to steep, shaded valleys. But in this place of abundant natural beauty, there is also keen scarcity when it comes to potable drinking water.  

Although the reservation sits atop Arizona’s largest aquifer, the water it contains is too salty for consumption. That means that nearly half of the Nation’s 175,000 inhabitants must drive long distances, several times each week, just to obtain enough water for their basic needs. 

The answer to this dilemma might be found hundreds of miles away, where scientists with the UA’s Institute of the Environment are devising a potential solution. They’ve developed an ingenious water purification system that relies on the sun for its power, can easily be maintained, and might someday be readily available from store shelves.  

For reservation dwellers such as Rosie Sekayumptewa, the device could prove life-changing. Sekayumptewa returned to the reservation after three decades in Phoenix. She rediscovered the challenges of her youth, with water scarcity topping the list.

Sekayumptewa’s struggle — and the fresh hope offered by UA scientists — is the focus of Seeking Water from the Sun, a poignant documentary produced by Arizona Public Media. The film depicts her traveling to retrieve water and demonstrating how she counts every cup.  

“It’s a beautiful place, though it’s a little bit of harsh living,” Sekayumptewa confides to the camera. “Out here we don’t have running water.”

If Wendell Ela has his way, her dilemma may soon end. The UA professor of chemical and environmental engineering is helping spearhead the project, which aims to purify Navajo Country’s immense underground preserves, one well at a time.

The UA technology could also prove invaluable for an increasingly thirsty planet and arid lands around the globe, where enormous underground reserves of brackish or salty water go largely untapped.

“The larger context is to develop systems that would be amenable to any off-grid situation where water and energy infrastructure is not available,” says Ela. “From that perspective, the Navajo Nation is a key example — and a pressing one in terms of need.  

“At the technical level, it’s an engineering project,” he says. “But it also involves a significant amount of socioeconomic research,” because the system must be available, affordable, and easily maintained.

That means using components already on the market, such as sun-tracking solar collectors to power the distillation system. As water that cools those solar panels heats up, it also boosts the distillation in 10-inch, membrane-lined evaporation canisters. Water vapor then flows to a condenser, where it is reconstituted — minus the salt. 

“The objective,” says Ela, “is to make a system that’s robust enough to stand alone up there and persevere.” 

And if the Navajo Nation finds water salvation, you can bet the rest of the world will be watching. “There are tremendous water resources that we don’t use at all,” says Ela. “If technology such as this could start accessing those water resources, then it would certainly give us a lot more breathing room — and get water to the people who need it.”