[sithadmin]

It's not as easy as 'dilute and spread' -- highly concentrated brine doesn't really mix readily (halocline effect) when released back into the sea.

[konschubert]

Couldn’t there be some kind of dilution step in the plant, using pumps to mix it 1:10 with seawater?

After that, it’s just slightly more salty seawater.

[sithadmin]

Relatively small differences in dissolved salts are enough to cause halocline barriers that don't really mix well and still pose a hazard to local flora/fauna.