Worldwide present water stress situations lead to the necessity to use alternative water sources like brackish water or wastewater. To enable this, new desalination technologies like electrically driven membrane processes have to be implemented. These technologies were used to desalinate the reverse osmosis concentrate of a process water treatment plant up to a certain point, at which the resulting diluate could be used as feed water for the reverse osmosis. As a result, the concentrate volume to be discharged was halved and the permeate yield of the overall plant was increased. A focus was set on the required energy consumption for the additional treatment step.