​The Moving Bed Biofilm Reactor (MBBR) is an efficient biological treatment technology that can function as a standalone system or be integrated with the activated sludge process to enhance overall treatment performance. By adding high-efficiency bio-carriers into the reactor, the biomass concentration can reach 5–10 g/L, and the treatment load can be as high as 6 kg BOD/m³·d, significantly reducing the required land area. The biofilm developed on the carriers provides a long sludge age and high concentrations of nitrifying bacteria, resulting in excellent nitrification and denitrification capabilities. MBBR is particularly effective in nitrogen and phosphorus removal, with ammonia nitrogen removal rates exceeding 90%, and promotes the formation of dominant nitrifying microbial communities.