How Does a Water Desalination Plant Handle Brine?

For every litre of fresh water a reverse-osmosis plant produces from seawater, roughly 1–1.5 litres of brine (at about twice the original salinity) is generated. The most common disposal method is ocean outfall: brine is piped offshore and released through multi-port diffusers that rapidly dilute it to near-ambient salinity within tens of metres, minimising ecological impact. Alternative approaches include mixing brine with power-plant cooling water for pre-dilution, evaporation ponds in arid areas, and deep-well injection. Emerging "zero-liquid-discharge" (ZLD) technologies evaporate all the water and crystallise salts for commercial use — recovering magnesium, gypsum, and even lithium — but these are energy-intensive and not yet widely adopted.