The purpose of this study is to propose a nanofiltration /electrodialysis process for nickel recovery from a metal plating industry. Nickel recovery in the metal plating industry has been studied widely by other process such as chemical precipitation and ion exchange. However, the complication of sludge and resin regeneration has been a problem and is not feasible for the industry, resulting in the high operating cost. The cooperation company in this project is Concert Environment Technic Company, which is a consultant company who work with traditional metal plating industry. The nickel waste has been presented in their waste stream and ion-exchange process was not successful for them. Nanofiltration was typically used for multivalent ion removal; thus the separation of monovalent and multivalent ions can be achieved. Electrodialysis is a membrane separation process based on the selective migration of aqueous ions through ion-exchange membranes under electrical driving forces. It has been commercially used for desalination, wastewater treatment and electrolyte separation for electroplating wastewater. In order to recover the nickel and water, this study designs a model which has nanofiltration combined with electrodialysis. In the first stage, nanofiltration was proposed to retain Ni2+ in the concentrate stream but other monovalent such as sulfamate, chloride and small organics, can be removed by passing through membrane. Thus in the electrodialysis stage, nickel can be concentrated. The optimum mass recovery is about 93% with system recovery of 90 % or 9.3 times of the initial concentration increase. Electrodialysis is able to recover the reamianing 10 mass % of nickel and also to meet the discharge standard. This research will be able to reduce their operating cost by recovering nickel and water, also solve their current problems for their wastewater containing nickel and also for many similar metal plating companies in Taiwan. Comparing to the traditional process, the NF/ED will be more economical after 17.7 month of operation.

Metal plating industry, nanofiltration, electrodialysis, sep