2 ms·

Since you don't want to just Google the answer for why they're not already doing this, I'll do it for you. http://www.sidem-desalination.com/Process/FAQ/ http:

• raverbashing 11y ago
  And? "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" You'll just start with something more concentrated instead of seawater Yes, you might have a reason to not want to do that, it might be easier/cheaper to just throw it back into the sea