When Professor Noreddine Ghaffour started working in water desalination, freshwater shortages were a concern in only a handful of regions: the Gulf states, parts of North Africa, and a few other arid zones where scarcity was a fact of life. By now, though, water scarcity has spread to places where no one thought it would ever occur, said Professor Ghaffour. “Even in the North.” In Europe, for example, both the United Kingdom and the Netherlands now operate desalination plants.
Unfortunately, today more regions around the world are running out of fresh water. Although water covers roughly 70 percent of Earth’s surface, only about 3 percent is fresh, and less than 1 percent of that is easily accessible.
Climate change, population growth, and rising consumption are all shrinking available supplies. A 2026 report by the United Nations show that three-quarters of the world’s population now live in countries classified as water-insecure, with around four billion people suffering severe water scarcity for at least one month each year.
Properly treated wastewater can serve many purposes in industry and agriculture, reducing the need for desalination without tapping new sources
Fortunately, dedicated researchers are finding new ways to produce fresh water. Professor Ghaffour, who has been a professor since 2010 at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, runs hundreds of experiments a year in pursuit of better, cheaper, and more flexible approaches to turning unusable water into a water that people can drink, grow food with, or put to industrial use. His work earned him a 2025 Kuwait Prize in Environmental Sciences.
Typically, desalinated freshwater is produced from seawater or brackish water. Two methods have long dominated the field. Reverse osmosis, which forces seawater through a very fine membrane under high pressure, leaving the salt behind, and thermal desalination, which heats seawater until it evaporates, then collects the condensed vapor as fresh water.
For a long time, both approaches came with significant drawbacks. The most significant being an excessive energy consumption. Reverse osmosis requires large amounts of electricity to maintain the pressure required to push freshwater through the membranes while thermal processes demand substantial heat. Moreover, both methods produce brine — a concentrated salty byproduct that has long been thought to harm marine ecosystems if returned to the sea without treatment.
However, newer advances, including some from Professor Ghaffour’s and his team, have gone a long way toward addressing these challenges. For example, they have recently developed a membrane — an ultrathin polymer film — that can desalinate water at nearly ambient temperature and pressure, using low-grade thermal energy that can be readily brought from waste heat, solar panels or other renewable sources.
The membrane, which is currently being tested at pilot scale, could enable smaller, decentralized desalination plants. Not only could such plants bring clean water to rural communities that are too remote for conventional desalination, but their smaller scale would ease other challenges, too. “If you have smaller volumes of brine, you can treat it more easily,” Professor Ghaffour said.
Additionally, brine may prove less of a threat than once feared. In Australia, which built a fleet of coastal desalination plants during the severe drought of the 2000s, brine became a flashpoint for environmentalists. Nevertheless, divers and researchers have found that long‑running plants still have fish around their outfalls, suggesting impacts may be less severe than had been assumed, Professor Ghaffour noted. By now, some experts even see the abundance of minerals in brine as an opportunity rather than a liability. “Brine mining is a hot topic,” said Professor Ghaffour.
Some of the approaches Professor Ghaffour is pursuing appear almost counterintuitive. For example: desalinating water only partially. In arid regions, a lot of desalinated water goes to agriculture, but standard desalination strips this water of virtually all dissolved ions — including minerals that are beneficial to plants. Farmers then must add those nutrients back as fertilizer. Professor Ghaffour’s team is developing processes that can be tuned to a specific crop, removing only what the plant cannot handle — sodium and chloride, typically — while leaving behind the calcium and magnesium that it needs. Partial desalination will make agriculture water cheaper, said Professor Ghaffour, “because the less you remove the better.”
Professor Ghaffour and his team recently have developed an ultrathin polymer film that can desalinate water at nearly ambient temperature and pressure, using low-grade thermal energy that can be readily brought from waste heat, solar panels or other renewable sources
The breadth of his work reflects his wide technical background. He trained originally as a mechanical engineer, then moved into membrane separation technology during his master’s degree and doctoral research at the University of Montpellier in France, and later encountered desalination through an industry project on treating wastewater from oil wells. That grounding in thermodynamics, fluid mechanics, and materials science allows him to approach problems from angles a more specialized researcher might miss. In one collaboration, for example, his team developed a system that captures fresh water from the frost that forms on refrigeration units — recovering a water source while improving the unit’s energy efficiency. In 2024, Saudi Arabia granted him citizenship for his contributions to desalination — a rare honor.
He is confident that technology can help ensure the world has the fresh water it needs even as water stress spreads. However, desalination should not be the first resort, he cautioned: Many water crises stemmed from poor management rather than scarcity — not capturing enough rainwater, for example. “We should not go for desalination if we have other, cheaper solutions,” he said.
We should also learn to reuse water better, Professor Ghaffour added. Properly treated wastewater can serve many purposes in industry and agriculture, reducing the need for desalination without tapping new sources. While some countries already reuse up to 80 percent of their water, many others are not even close.
“Every drop of water is important,” Professor Ghaffour said.
