I'm sorry, perhaps my engineering education makes me handwave at problems -- but the water we're desalinating has to return to the ocean someway, it's not like

I'm sorry, perhaps my engineering education makes me handwave at problems -- but the water we're desalinating has to return to the ocean someway, it's not like we throw it into black holes, why can't we just dump the brine 20 miles into the ocean, the water we've desalinated will return by other means.