Critical challenges in high-salinity seawater reverse osmosis systems: Technical, energy, and environmental reviews

Despite Earth's abundant water supply, global freshwater scarcity persists due to the limited availability of freshwater resources, highlighting the urgency of developing innovative desalination technologies. The growing water demand has driven the rapid expansion of seawater reverse osmosis (SWRO) systems. However, since most of the favorable locations for SWRO plants are already occupied by existing plants, new installations are increasingly focusing on high-salinity seawater feeds, which presents technical, energy, and environmental challenges. This paper reviews critical issues associated with high-salinity SWRO systems, focusing on technical, energy, and environmental aspects. High-salinity seawater desalination involves the treatment of feed water with salinity exceeding 40 g/L or brine concentrations over 80 g/L. This review categorizes advanced SWRO systems based on their operational principles, with practical conditions for real-world applications considered. The performance of these systems is compared based on specific energy consumption data, revealing energy-saving opportunities in high-salinity seawater treatment processes. Environmental challenges are addressed through brine discharge modeling, life cycle assessment, and exergo-environmental analysis, providing insights into minimizing environmental impacts. Nonetheless, developing low-energy, sustainable desalination systems with minimal environmental impacts requires a systematic framework. Overall, this paper comprehensively reviews the challenges associated with high-salinity seawater desalination and outlines potential research directions for addressing them.