The present disclosure relates generally to oxidation of ammonia using electrochemistry. Methods and systems may include at least one sensor to measure the concentration of ammonia in the effluent and/or the concentration of chlorine gas in the effluent. Methods and systems may also include at least one controller in communication with the sensor and/or the anode to reduce the current density of the anode generating the chlorine, and/or to change the flow rate of the ammonia containing water entering the reactor.