In the context of expanding industries in Arizona such as semiconductors, batteries, pharmaceuticals, food and beverages that require ultra-pure water, saltwater treatment has become a critical issue. Saltwater is a saline byproduct from processes like reverse osmosis, and in inland regions like Arizona, saltwater disposal poses particular challenges. However, Arizona State University (ASU) associate professor of civil and environmental engineering, Shanawaz Sinha, views it as an opportunity. Partnering with Nestlé, and supported by ASU's Arizona Water Innovation Initiative and the Global Water Technology Center, he is developing a mobile closed-loop water recycling demonstration facility that could transform how industries in the metro Phoenix area manage concentrated brine.

Arizona faces severe salinity challenges. While the Phoenix metropolitan area does not deal with road salt in winter or seawater desalination, as Colorado River water flows through the state's arid regions and open canals, salt concentrates due to evaporation. The valley's natural saline soils, Salt River, and its tributaries passing through salt mines leave salt residues in drinking water, becoming the source of saltwater after manufacturers produce ultra-pure water. For instance, Nestlé's factories need it for product quality and food safety, while chip manufacturers like TSMC and Intel require it to avoid damaging wafers or disrupting processes. Discharging concentrated brine into sewers increases wastewater treatment costs or affects irrigation with treated water. Bureau of Reclamation studies show that salt pollution costs Arizona over $30 million annually in economic losses, making innovative saltwater treatment methods essential for local water security and economic prosperity.

In this context, industry collaboration has emerged. Nestlé's Arizona production facilities generate over 50,000 gallons of brine daily, with high transportation costs. Nestlé saw this as an opportunity and sought help from ASU. Sinha's team first analyzed the brine, finding it clear but highly saline, becoming white and thick as processing concentrates it. The team adopted a multi-step system: pre-treating to remove larger particles, then reverse osmosis to separate high-quality water and saline concentrate; hydrophobic membranes recover purer water from the concentrate; high-concentration brine is sent to dryers and crystallizers to revert to solid salt products; and atmospheric water collectors capture remaining vapor. The goal is to recover 50%–90% of the water, yielding manageable crystallized salt, greatly easing the burden on trucks and wastewater plants.

In the collaboration, Nestlé and ASU mutually benefit. Nestlé provides skilled engineers and water plant operators, with bi-weekly meetings for exchange, while ASU brings fresh insights. Nestlé also suggested broader alliances. In May this year, the Global Water Technology Center and the National Science Foundation's (NSF) Southwest Future Engine convened manufacturers, water suppliers, technology developers, and researchers to map a roadmap for reducing saltwater management's barriers to economic development. Nestlé employees appreciate the partnership, citing gains in testing innovative water management methods, ASU expertise, and workforce development. ASU uses it to provide practical experience to nearby community college students, serving as a training base for both students and Nestlé employees.

Looking ahead, Sinha sees this project as part of a shift in thinking about water, waste, and resource recovery, with potential opportunities to extract commercially valuable minerals like salts from concentrated brine. Although the technology is currently expensive, industry is ready to invest, and Nestlé not only considers its own factories but sets an example for others relocating to the region. In areas where water is critical and salinity a long-standing issue, finding sustainable closed-loop methods is both a scientific challenge and economic necessity—as Sinha says, "not a single drop of water should be wasted."