Ghadeer Hasanin worked with KAUST's Professor Johannes S. Vrouwenvelder and industry partner ACWA Power to explore ways to improve membrane efficiency in seawater desalination. © 2023 KAUST; Eliza Mkhitaryan.

Identifying the components of membrane antiscalants that cause biofouling could help make seawater desalination a more sustainable source of fresh water.

“Safe drinking water is a human right,” says environmental scientist Graciela Gonzalez-Gil, “yet roughly 800 million people have no access.” The United Nations estimates that demand for fresh water could exceed the natural water cycle supply by as much as 40 percent by 2030.

“Seawater desalination — particularly by reverse osmosis (SWRO), which involves pressurizing seawater through a membrane at high pressure to remove salt and impurities — has become a widely adopted low-cost source of drinking water in arid coastal countries,” says Gonzalez-Gil’s colleague and KAUST alumni Ratul Das, who now works as Head of Desalination R&D for energy company ACWA Power, which has 16 water seawater desalination plants across four countries.

From left: KAUST research scientist Graciela Gonzalez Gil, ACWA Power’s Ratul Das and KAUST alumna Ghadeer Hasanin discuss their results. © 2023 KAUST; Eliza Mkhitaryan.

However, SWRO is energy intensive, and the used membranes create a lot of waste. Seawater is typically pretreated with antiscalants to prevent the scaling of salt on the membranes. “The low cost of these chemicals compared to other methods helps keep water prices low, hence their popularity,” says Das. But many of them trigger fouling by promoting microbial growth.

“Desalination operators are not fully informed about why and to what extent antiscalants cause biofouling,” says Gonzalez-Gil. “Measuring the bacterial growth caused by different antiscalants and linking this to their chemical composition can help these operators select products with minimal biofouling.”

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