System and method for treating ammonia-based wastewater

A method for treating ammonia-based wastewater, comprising:

• conducting ammonia-based wastewater into a first reactor, wherein the first reactor comprises denitrification bacteria for denitrification;
• conducting effluent of the first reactor into a second reactor, wherein the second reactor includes an aerator and aerobic heterotrophic bacteria, and has an HRT (hydraulic retention time) of less than 6 hours for reducing the organic materials and decreasing the C/N ratio in an effluent of the second reactor;
• conducting the effluent of the second reactor into a third reactor, wherein the third reactor comprises nitrification bacteria to convert ammonia in the effluent of second reactor to nitrite and nitrate, and the nitrification bacteria are carried on carriers in the third reactor;
• and
• conducting effluent of the third reactor into a solid-liquid-separating reactor for separating the solids and liquids in the effluent of the third reactor.