Solving water access issues with solar energy

ANN ARBOR—Imagine living in a community where your drinking water must be trucked in because the wells in your town were so depleted that seawater could leach into the freshwater supply.

In many arid coastal areas, this is an everyday occurrence. A team of students and a professor at the University of Michigan along with colleagues at the University of Sonora in Mexico, have developed a prototype single-stage distillation unit powered by solar energy that desalinates water in these areas.

The prototype unit can distill 150 liters per day and can be scaled up to 3,000 liters of water a day. That’s equal to five truckloads of fresh water and a much more eco-friendly solution to the problem of insufficient access to fresh water, said Jose Alfaro, an assistant professor at U-M’s School for Environment and Sustainability.

“We developed this product with a particular community in mind, but we realized that it would be good for a number of communities,” he said.

They designed the system for Tastiota, a small village in the Sonoran desert, which had been trucking in its water from a source 100 kilometers away. After distillation, what’s left is brine that can be converted to salt and sold to other businesses nearby, creating a circular economy.

Other markets for the desalination unit include the global sunbelt located several degrees above and below the equator and hotels in coastal communities, Alfaro said.

“Hotels could use this to reduce their impact on the areas they are serving,” he said. “A lot of the locations of these hotels are in fragile basins at risk of getting saline intrusion.”

Alfaro and the students, Iulia Mogosanu, who graduated in the spring with an MBA, and Pablo Taddei, who graduated with a master’s degree in sustainable systems in 2017, wanted to create a sustainable solution to water scarcity issues in coastal communities where arid conditions, rising temperatures and decreased precipitation due to climate change exacerbate the problem.

Over the past year, the team developed a proprietary process to remove salt from local water sources by leveraging solar radiation to power an innovative desalination technology. Early analysis indicates that the combination of concentrated solar power and single-stage distillation will provide a cost-effective and easy solution to water scarcity issues.

What makes this solution truly sustainable is the business component. This technology results in both a sellable byproduct, by processing brine into salt, and an improved capacity for coastal fishers to bring their catch to larger markets. This significantly improves the technology’s financial viability and provides a true market solution.

Mogosanu said that while studying with Taddei at U-M’s School for Environment and Sustainability they realized that they were both interested in the energy industry and alternative uses of renewable energy technologies. Taddei is a native of Hermosillo County in Mexico—a region that is along the Sonora coast.

Hermosillo, as with many coastal communities, has been experiencing severe water scarcity due to saline contamination of the wells, which is further aggravated by low precipitation. Taddei was interested in finding a sustainable solution to this problem and subsequently began probing ideas that would desalinate the abundant source of ocean water.

“I realized that the potential of such a solution had far-reaching implications globally. It was clear to me that the commercial potential of this idea was scalable to different conditions in different regions of the world,” Mogosanu said.

Richard Greeley, a senior licensing specialist for engineering at U-M Tech Transfer, said that while many startups attract venture funding, Alfaro’s project may also appeal to a foundation as the work is humanitarian in nature.

And that’s been the case so far with funding from the Center for Sustainable Systems, the Energy Institute and the Erb Institute, with seed funding from the Graham Institute. The prototype has been built and tested with help from the University of Sonora in Hermosillo.

“Professors and students there have been key in our ability to develop the project and most importantly in physically putting it together,” Alfaro said.

Just last month, Alfaro traveled to Costa Rica to determine if there were communities that might benefit from the distillation unit. Working with a United Nations official, he plans to run a pilot program on a small island there where water is brought in by boat.

To work, the area needs direct sunlight, a good governance system around the water that would run the desalination units after initial set up by Alfaro’s team, and a need for potable water. The team also plans to market to communities in West Africa, Lima, Peru and along the coast in Chile.

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