Desalination is a one of the major water treatment process that removes dissolved contaminated minerals (including but not limited to salt) from seawater, brackish water, or treated waste water. Desalination water treatment plants may use seawater (directly from the ocean through offshore intakes and pipelines, or from wells located on the beach or seafloor), brackish groundwater, or reclaimed water as feed water. Since brackish water has a lower salt concentration, the cost of desalting brackish water is generally less than the cost of desalting seawater.
In desalination water treatment plants that produce water for domestic use, post-treatment processes in water treatment plants are often employed to ensure that product water meets the health standards for drinking water as well as recommended aesthetic and anti-corrosive (corrosion control) standards. The desalinated water treatment product water is usually more pure than drinking water standards, and also highly acidic so when product water is intended for municipal purpose use, it may be mixed with water (water quality) that contains higher levels of Total Dissolved Solids (TDS) or adjusted for pH (Concentration of Hydrogen ions), hardness and alkalinity before supply. The product water recovery relative to input water flow is 15 to 50% for most seawater desalination water treatment plants.
The water filtration and water purification technologies generally adopted for the desalination water treatment process of saline water into fresh water, are as follows: