Method and device for treating wastewater containing tetramethylammonium hydroxide and ammonium nitrogen

A method for treating wastewater containing tetramethylammonium hydroxide (TMAH) and ammonium nitrogen includes the steps of introducing an ammonium-nitrogen-containing solution without TMAH into a single reactor, denitrifying the ammonium-nitrogen-containing solution by using microorganism including nitrifying bacteria and anammox bacteria under a dissolved oxygen concentration of 0.1-0.5 mg/L and pH of 7-8; when the denitrification efficiency reaches a steady state, introducing TMAH into the ammonium-nitrogen-containing solution in a concentration lower than 60 mg/L; and gradually increasing the concentration of TMAH in the solution to be added into the reactor for several times whenever the denitrification efficiency reaches a steady state. Accordingly, the inhibition of TMAH to the anammox bacteria can be significantly decreased, and both TMAH and the ammonium nitrogen can be treated simultaneously.