What happens to the salt?
The desalination plant typically uses three kilograms of seawater to produce 1 kilogram of fresh water. The extracted salt dissolves in the excess sea water used in the process to form so-called brine. The brine is returned to the sea where it is diluted again in its natural medium.
Can salt be recovered?
The usual desalination processes do not provide for such recovery. Whereas they concentrate seawater 1.5 times, recovery of salt would require seawater to be concentrated ten times. Under such conditions the first crystals would appear in the brine. This would require a lot of energy and cannot be justified on an economic standpoint. Today whenever a large surface area is available close to a sunny seashore, salt pans, which make use of solar energy, are still the best method of salt production.
“The Hidden Salt Ponds of Chula Vista” (San Diego)
http://voiceofsandiego.org/2008/06/16/the-hidden-salt-ponds-of-chula-vista/
The Confederacy had salt works along the Florida Gulf coast during the War Between the States. All they had to do was boil the seawater off leaving salt.
With the brine at a high concentration, it would be easy to boil it off. Maybe the salt is not worth it for what it would take to get it.
Case in point is Bonaire, NA. The desalinated water is wonderful. The salt pans, which have been in production for hundreds of years, provide a medium for algae growth. The flamingos on the island frequent the salt pans and feed on the pink algae, which gives the birds their coloration.
Not all the pans are pink. Some are green, some are blue and some are white. Different species of algae, I suppose.
Bonaire is a diving destination with one of the world’s first Marine Parks. The water teems with tropical fish and the residents all fish to supplement their income. If there was any problem with discharge from the desalination plants, it would have shown up by now. The island is always hosting one or another Marine Biology of environmental conference or study.