ABSTRACT
Water is an essential resource and has become a basic necessity to satisfy the needs of human life. Even today, freshwater scarcity is an issue of concern in many parts of the world. Only 3% of the water on earth is freshwater and viable for human use. Brackish water is an alternative source of water that can be treated and reused. It is a category of saline water formed when freshwater meets seawater. It is more saline than freshwater and less salty than the sea and ocean water. The average salinity of brackish water ranges between 0.5 and 30 ppt. The specific gravity of brackish water ranges from 1.005 to 1.010 and is mostly observed at places like estuaries. Along with salts, brackish water may also contain both physical and chemical properties that include parameters such as acids, bases, TOC, etc. The salts in brackish water may also contain sodium (Na+), potassium (K+), nitrate (NO3 −), magnesium (Mg2+), calcium (Ca2+), chloride (Cl−), sulfate (SO4 2−), carbonate (CO3 2−), and bicarbonate (HCO3 −), along with sodium chloride (NaCl). These total dissolved salts in brackish water are designated to be around 1,000–2,000 ppm. The treatment of brackish water is challenging to maintain sufficient water quantity for human needs, especially in arid regions. Researchers have started developing treatment technologies since the early 17th century but due to prospective freshwater shortage, improving the efficacy of saline water treatment gained momentum in the past few decades. With effective treatment technology, brackish water can be used for ecosystem services and human consumption, including irrigation, industry, and land management practices. This chapter discusses the current applications and major treatment technologies used worldwide to treat brackish water. The treatment of brackish water can solve the problems of water scarcity and the ongrowing water demand with human population.
