Reverse electrodialysis (RED) is a promising technology to simultaneously generate electricity and degrade pollutants in wastewater using salinity gradient energy. The present study focuses on the degradation of ammonia and simultaneous generation of electricity by RED stacks. The results indicated that increasing the chloride concentration in the electrode rinse solution, salinity gradient, and flow rate of the electrode rinse and saline solutions can enhance the output current of RED and ammonia removal rate. The maximum ammonia removal and output power density with RED was 98% and 0.06 W/m(2), respectively, while the optimal flow rate of electrode rinse and saline solutions was 250 mL/min and 50 mL/min, respectively. In the electrode rinse solution, active chlorine was generated in the anode chamber and degraded ammonia, which followed the indirect oxidation mechanism and made the main contribution to ammonia removal. A small quantity of monochloramine and dichloroamine were generated as intermediate oxidation products in the process, indicating that ammonia was chlorinated in a stepwise process and finally converted into nitrogen. These findings prove the feasibility of simultaneous electricity generation and ammonia removal, and pave the way for a new application of RED technology. (C) 2018 Elsevier Ltd. All rights reserved.