Practical implementation and challenges of current batch-type RO systems and future potential: A review

The global water crisis, intensified by climate change and population growth, necessitates efficient desalination technologies to ensure sustainable water management. By 2050, over 60 % of the world's population is expected to face water shortages, while in 2022, only 57 % had access to safe sanitation services. Reverse osmosis (RO) has emerged as the most effective desalination method, offering high salt rejection (∼99 %) and favorable energy efficiency (2.0–5.5 kWh/m³ for seawater). Although innovations such as high-recovery and hybrid RO systems have improved performance, selecting the optimal desalination technology based on feedwater conditions and energy constraints remains a significant challenge. Among these technologies, batch-type RO has attracted attention for its potential energy savings and operational advantages. However, despite these benefits, a systematic framework for designing and prioritizing batch-type RO configurations under varying conditions remains lacking. This review evaluates various batch-type RO configurations, analyzes their recent advancements and theoretical underpinnings, and proposes a perspective and set of recommendations for identifying appropriate operational conditions and selecting optimal technologies based on specific technical and policy-driven considerations.