Technologies for Desalination of Brackish and Sea Water

This chapter thoroughly examines various brackish and seawater desalination technologies, including thermal- and membrane-based methods. Conventional thermal methods account for roughly one-third of the world’s installed desalination capacity. This work provides an in-depth analysis of traditional thermal techniques such as Multi-Stage Flash (MSF) distillation, Multi-Effect Distillation (MED), and Mechanical Vapour Compression (MVC), along with innovative methods like solar-driven evaporative desalination processes. The analysis of these methods includes their principles, and performance metrics. Membrane Distillation (MD) offers an innovative solution, positioned between thermal and membrane-based technologies. This advanced technology is comprehensively presented and discussed in detail. The discussion extends to membrane-based desalination technologies, particularly pressure-driven processes such as Reverse Osmosis (RO), which is currently the most widely used method. The chapter further explores the operational principles of RO, its advantages, limitations, and technological advancements. Additionally, emerging membrane technologies such as Nanofiltration (NF), Forward Osmosis (FO), and Osmotically-Assisted Reverse Osmosis (OARO) are examined, highlighting their potential and current applications. Among electrically driven membrane processes, Electrodialysis (ED) has received special attention. This chapter provides insights into its operational mechanisms, efficiency, and applications, along with a discussion on Electrodeionization (EDI) and Electrodialysis with Bipolar Membranes (EDBM). For each category of desalination technology, water desalination plants currently operating worldwide are classified based on their production capacity, the technology used, and geographical distribution. This classification offers a practical overview of the global deployment of desalination technologies and their regional adaptations. The chapter also delves into hybrid systems in water desalination, which aim to combine and integrate the advantages of various desalination technologies to develop more efficient and sustainable systems. Several examples of such integrated systems, including renewable energy-driven desalination systems and integrated membrane technology desalination systems, are described and briefly discussed. The potential for coupled hybrid systems to address specific challenges in desalination is also explored. Future research in water desalination is expected to focus on these hybrid approaches, optimizing the integration of different technologies to enhance water recovery, energetic performance and sustainability. This chapter serves as a comprehensive resource for understanding current desalination technologies, their global application, and future trends in the field.