Biological Seawater Desalination

Abstract

More than two billion people worldwide lack access to safe, clean drinking water, and this number is likely to increase due to population growth and rapidly diminishing freshwater supplies. Current seawater desalination methods can effectively provide freshwater and meet the growing demand for this resource. However, they are becoming increasingly controversial owing to their adverse environmental impacts, including high energy consumption and generation of desalination brine. For millions of years, various species of organisms such as plants, microalgae, and bacteria have adapted to environments with variable salinity and have developed mechanisms to eliminate excess intracellular NaCl. This has encouraged scientists to study the possibility of using biological processes for seawater desalination. Biodesalination is an emerging technology for the selective removal of Na + and Cl − from salt water by various halophile organisms, such as macrophytes, microalgae, and cyanobacteria, with very low energy consumption. Microbial desalination cells that allow simultaneous desalination of water in conjunction with wastewater treatment are also included in this category. The direct use of living organisms such as halophile plants, microalgae, and bacteria to desalinate water appears to be a promising field. However, the development and practical applicability of these technologies depend on the living organisms selected for desalinating seawater.