Desalinaatioon

Desalinaatioon is the illative form of the Finnish noun desalinaatio, referring to desalination, the process of removing dissolved salts from saline water to produce fresh water. Desalination is used to augment freshwater supplies in regions with limited rainfall, high population density near the coast, or where groundwater salinity is too high for direct use. Common feedwaters include seawater and brackish groundwater, and desalination can provide drinking water, industrial process water, or irrigation supplies when other sources are scarce.

The main technological families are membrane processes and thermal processes. The most widely applied method is reverse osmosis, in which high-pressure water passes through semi-permeable membranes to separate salts. Thermal approaches include multistage flash and multi-effect distillation, which evaporate water and condense the vapor as fresh water. Electrodialysis uses ion-exchange membranes and is commonly used for lower-salinity brackish waters. Hybrid systems combine techniques to improve energy efficiency and reliability.

Costs and energy use vary by technology, salinity, plant size, and energy prices, but desalination is generally energy-intensive. Modern plants employ energy recovery devices, optimized pretreatment, and, increasingly, renewable energy sources. After desalination, water often requires remineralization and disinfection to meet drinking-water standards.

Environmental concerns include brine disposal, intake effects on marine life, chemical pretreatment, and thermal or chemical discharges. Proper site selection, brine dilution, and regulatory controls help mitigate impacts. Desalination plays a growing role in water security for many arid and coastal regions, though it remains one option among others such as water conservation and re-use.