Next-generation seawater reverse osmosis desalination: toward high-recovery systems through process retrofitting and system-level integration

초록

Seawater reverse osmosis (SWRO) is the dominant technology due to its comparatively lower electrical energy consumption and cost-competitiveness, compared with thermally based technologies. Despite investigations into the development of SWRO-based seawater desalination using an energy recovery device (ERD), advanced membrane materials, and optimization of the SWRO process, minimizing SWRO's energy consumption remains constrained by feasibility and thermodynamic limitations. Because environmental constraints such as brine discharge and sustainability have become more significant, the performance requirements for seawater desalination have shifted in recent years. In previous studies, the specific technological focus was narrow, and there is a lack of integrated analysis of energy consumption and water recovery across various seawater desalination technologies. Therefore, this review applied a retrofitting-based perspective and classified seawater desalination technologies based on SWRO into pretreatment, fouling control, energy recovery, process configuration, and water recovery extension. The technologies were compared using common criteria, including feed salinity, operating pressure, water recovery, specific energy consumption, process maturity, operational limitations, and compatibility with existing seawater desalination plants. It is not enough to meet the growing future demand for desalination by focusing solely on improving conventional energy efficiency. In the next generation of SWRObased seawater desalination, considerations of energy consumption, water recovery, and environmental impact should be integral to the paradigm-shifting integrated design. Particular attention was given to closedcircuit reverse osmosis (CCRO), low-salt-rejection reverse osmosis (LSRRO), high-pressure reverse osmosis (HPRO), osmotically assisted reverse osmosis (OARO), and disc-tube reverse osmosis (DTRO). Based on this comparison, a purpose-based framework was proposed to support technology selection and system integration. This review provides a comprehensive roadmap for the evolution of SWRO from energy-minimized systems to recovery-extended, sustainability-driven desalination, offering critical insights for both research and industrial implementation.

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