But the processing and shipping isn’t the problem with desalination. The problem is that dumping bribe or salt into the ocean can kill local wildlife.
Seriously though, far out to sea away from any landmass it's pretty much a desert. Any salt dumped there would disperse very quickly and not pose a problem to wildlife.
Almost every part of the world ocean has been described as a desert, before people went under and looked. It turns out there's a huge amount of life everywhere you look, even miles down.
But there is also a lot of room, so anything localized, unpleasant, and temporary can be swum away from.