Electrowinning of Ni is an opportunity for galvanic industry to remove Ni from water rinses; due to low Ni concentration the operation is not easy as electroplating depends strongly from metal concentration. I am aware of an Italian company that uses highly porous carbon as cathode in the way to maximize cathode surface and extract as much Ni as possible; a technology that can increase Ni concentration before could be helpful (i.e. nanofiltration).