Experiments on the electrochemical oxidation of ammonia in artificial seawater are carried out in a lab-scale electrochemical apparatus. The operating parameters are current density (16-66 A/m(2)) and hydraulic residence time in a reactor (30-90 sec). The ammonia concentration in the effluent of the reactor exponentially decreases with increasing the current density and the hydraulic residence time, while the concentration of chlorine residuals increases. Most of the chlorine residuals are free available chlorine and the remainder is dichloramine. A strong disinfection characteristic can be seen during electrochemical treatment of ammonia.