Desalinization

Desalinization, also desalination, is the process of removing dissolved salts from saline water to produce fresh water. It is used to supply potable water and for industrial needs in regions with limited or contaminated freshwater resources. Saline sources include seawater and brackish groundwater; the resulting water is treated to meet drinking-water standards and may be remineralized for taste and health considerations.

Desalinization methods are grouped into thermal and membrane processes. Thermal methods heat water to produce vapor, leaving salts behind. Variants include multi-stage flash, multi-effect distillation, and vapor compression. Membrane processes use selective barriers to separate water from ions, with reverse osmosis being the most widespread. Other membrane options include nanofiltration and electrodialysis; forward osmosis is explored in pilots and niche applications, especially for brackish water or energy-efficient configurations.

Energy use is the main cost and environmental concern. Thermal plants are energy-intensive; membrane systems likewise require electricity but can incorporate energy recovery devices and renewable power. The disposal or management of highly concentrated brine is an environmental issue for coastal and marine ecosystems, prompting research into zero-liquid-discharge approaches and brine minimization.

Desalinated water may be remineralized to improve taste and essential mineral content. The technology is widely deployed in arid regions such as parts of the Middle East, North Africa, and coastal cities worldwide, and its use is expanding as demand for reliable water supplies grows. Ongoing advances aim to reduce energy use, improve membrane performance, and manage waste streams more sustainably.