Reverse osmosis hybridization with other desalination techniques: An overview and opportunities

Several countries face water scarcity problems, so they utilize water desalination. Reverse osmosis (RO) is the most popular desalination process, but it consumes high-grade energy and produces concentrated brine. Combining the RO with other desalination technologies can increase water recovery, reduce energy consumption, and reduce environmental impacts. The current study presents a comprehensive review of previous studies and techniques combining reverse osmosis with other desalination technologies to increase the overall system performance and/or treat RO brines. It analyzes and discusses the strengths and weaknesses of various desalination techniques, economic feasibility, and prospective developments. The discussion includes energy consumption and recovery ratio (RR) and the advantages and challenges of combining different desalination systems to overcome the limitations of standalone cycles. Findings include factors such as daily water production, energy consumption, and cost. While hybrid systems show promising performance metrics, they have potential drawbacks or challenges: increased complexity of system integration, higher maintenance requirements due to the combination of multiple technologies, and potential compatibility issues between different desalination processes. The hybrid RO-MD (Membrane desalination) systems have the highest daily water production, ranging between 26,000–50,000 m3/day, at a specific energy consumption of 3.572 kWh/m3 with energy cost ranging between 0.85 and 0.9 $/m3. The RO-MSF (Multi-Stage Flash) systems showed a daily water production ranging from 14.4 to 1000 m3/day at specific energy consumption ranging between 5.2 and 6.7 kWh/m3 with energy costs between 1.35 and 1.84 $/m3. Finally, hybrid systems can minimize the cost of producing freshwater and mitigate the environmental problems of waste brine.