Techno-economic feasibility of decentralized desalination in the Navajo Nation

The Navajo Nation, situated in the southwestern United States, experiences significant water scarcity, with nearly 30% of households lacking piped water access. Extending centralized water infrastructure is not feasible in all cases and decentralized solutions remain largely unexplored, so people rely on bottled water. This study investigates the geographic, environmental, and infrastructural characteristics of the Navajo Nation to determine the viability of decentralized desalination for enhancing potable water access. To uncover key challenges, opportunities, and essential design requirements, interviews were conducted with a diverse range of stakeholders. These discussions brought to light a cultural reluctance toward wasting water, heightened sensitivity to operational costs, and two viable scales for system implementation: household and community. A preliminary economic analysis was carried out for both scales and findings indicate that household-scale systems present a stronger economic potential, primarily due to the region's low population density. The study then explores the technical feasibility of electrodialysis (ED) and reverse osmosis (RO) desalination technologies, guided by the identified design criteria for household systems. While both technologies can meet the requirements, notable distinctions exist: ED systems can recover over 70% of the feedwater, compared to 15%–50% for small-scale RO. However, ED technology remains unavailable in the household market, whereas RO systems are already commercially accessible.