TUCSON, Ariz. (KGUN) — Two years ago, Arizona state leaders were actively exploring the idea of a binational desalination plant that would bring water from the Sea of Cortez to the state. The plan, spearheaded by former Governor Doug Ducey, aimed to address the state’s growing water shortage. However, after facing backlash from water authorities and a lack of transparency, the project ultimately fell through. Later, Governor Katie Hobbs redirected funds away from long-term water supply projects, further pushing desalination off the table for the time being.
Despite these setbacks, one local researcher has continued to push the boundaries of desalination technology and is hopeful that his breakthroughs could provide a solution to the ongoing water crisis in Arizona. Professor Mark Witten, a researcher at the University of Arizona, has spent the past 17 years finding ways to efficiently remove salt from seawater.
In 2023, he shared his efforts with the public, explaining how his low-energy desalination technology could significantly reduce the cost and energy consumption typically associated with removing salt from seawater.
"We've gotten to the point where we can take out 99% of the salt from simulated ocean water," said Witten, reflecting on his progress.
His recent work has culminated in a groundbreaking discovery that allows for the removal of 335 parts per million (ppm) of concentrated salt, which is the same salinity level found in Earth’s oceans.
He was initially working with a silicon disc, and decided to try isolating salt by using a reactive metal. He experimented with tungsten, copper, iron, and magnesium. Witten described finding success with a small magnesium disc, so he purchased a larger disc.
Witten recalled, “When I first did the first experiment. I just bought a brand new salinity meter from Amazon, and it registered 333 parts per million after I did the desalination. Remember, I started out at 35,000 parts per million. So I thought something was wrong with my new salinity meter. So I went into my kitchen, filled a glass of water, and measured the salinity. It was 425 parts per million and I almost fainted because I thought I had hit the jackpot.”
Witten is confident that his technology can make a real difference. “Our technology, we believe, can produce an acre-foot of water for less than $400,” he said. An acre-foot is equivalent to one acre of land covered by a foot of water, a standard unit of measurement for water volume.
Beyond providing freshwater, Witten hopes his technology will provide more resources. He highlights that the salt could contain lithium, an essential component for electric vehicle batteries, which could help further support the green energy industry.
“We plan to collect the salt and mine lithium from it,” Witten explained. “The electric vehicle industry cannot grow without more lithium, and this could help address that challenge as well.”
As Arizona faces the very real threat of water scarcity, Witten’s innovative desalination technology offers a potential solution to one of the state’s most pressing issues. He believes that large-scale desalination could help protect Arizona’s future by ensuring a more stable and sustainable water supply.
“The future growth of this state, and the other states in the Colorado River Compact, is in danger because we don’t have enough water,” said Witten.
As the state continues to grapple with its water challenges, Witten sees a future where the ocean could provide an answer to Arizona’s water shortage. Witten’s next steps involve getting an industrial prototype of his desalination technology off the ground.
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Reyna Preciado is a reporter for KGUN 9, she joined the KGUN 9 team in July of 2022 after graduating Arizona State University. Share your story ideas with Reyna by emailing reyna.preciado@kgun9.com or by connecting on Instagram, or Twitter.
