desalination plant, about 15km south of Tel Aviv, is eerily unpopulated. This is the largest such plant in the world, producing as much as 230m cubic metres of desalinated water a year—about one-fifth of Israel’s domestic water supply. Yet only 20 staff are needed at any time to operate it. Seawater is piped in from over a kilometre out at sea.
That breakdown of where desalination is used hints at two reasons it is not a panacea. One is geography. If the sea is the feedstock it will be too costly to transport desalinated water long distances inland—to western China, for example. Secondly, even for coastal regions, desalination is very expensive, which explains why two-thirds of existing facilities are located in high-income countries. The expense comes partly in the capital cost of the plants.
The researchers worry about the threat that uncontrolled discharge of brine could cause to marine life. At the very least it raises the salinity of the surrounding seawater, depleting the dissolved oxygen. But in some places it may be accompanied by toxic chemicals used in the treatment process. More optimistically, they also point to opportunities to use reject brine, for example, in aquaculture, where it has achieved increases in fish biomass of 300%.
News flash:Water doesn’t disappear.