The article states > Modern desalination plants generally recover about half of the intake flow, which means their brine stream is about twice the concentratio

The article states > Modern desalination plants generally recover about half of the intake flow, which means their brine stream is about twice the concentration of normal seawater. I imagine this heavily depends on the actual plant design though. Also because of the above mentioned issues you generally don't discharge it like that but blend it with other water.