Total nitrogen removal device for sewage and method for operating the same

A total nitrogen (TN) removal device for sewage, comprising:

• a denitrification tank;
• a sedimentation and separation zone;
• a supplementary reaction zone;
• a first aerator;
• a second aerator;
• and
• a third aerator;
• wherein the supplementary reaction zone and the sedimentation and separation zone are arranged inside the denitrification tank;
• the sedimentation and separation zone is located above the supplementary reaction zone, and is communicated with the supplementary reaction zone through a three-phase separator;
• the denitrification tank is configured such that sewage therein is allowed to flow into the supplementary reaction zone;
• an overflow weir is arranged at an upper part of an inner chamber of the sedimentation and separation zone;
• an end of the overflow weir protrudes from a side wall of the sedimentation and separation zone;
• and sewage after nitrogen removal is allowed to flow out of the denitrification tank through the overflow weir;
• a flow guide pipe is arranged at an outer side wall of the sedimentation and separation zone and an outer side wall of the supplementary reaction zone;
• a water inlet of the flow guide pipe is arranged in a space formed by the outer side wall of the sedimentation and separation zone and an inner chamber of the denitrification tank;
• the water inlet of the flow guide pipe is higher than a water outlet of the overflow weir;
• and
• a water outlet of the flow guide pipe is communicated with a bottom of the supplementary reaction zone;
• a top surface of the sedimentation and separation zone is sealed;
• a diameter of the top surface of the sedimentation and separation zone is greater than a diameter of a bottom surface of the sedimentation and separation zone;
• and the supplementary reaction zone is filled with aerobic granular sludge;
• a membrane aerated biofilm reactor (MABR) assembly is arranged in a space formed by the outer side wall of the sedimentation and separation zone, the outer side wall of the supplementary reaction zone and the inner chamber of the denitrification tank;
• and a side wall of the denitrification tank is provided with an online chemical oxygen demand (COD) detector and an online nitrate nitrogen detector;
• the MABR assembly comprises a top plate, a plurality of MABR membranes and a bottom plate;
• two ends of each of the plurality of MABR membranes are fixed on the top plate and the bottom plate, respectively;
• the bottom plate is fixedly provided at a bottom of the denitrification tank;
• the top plate is fixedly provided at a top of the denitrification tank and/or the outer side wall of the supplementary reaction zone;
• and
• the first aerator is connected to the bottom plate of the MABR assembly;
• an air supply pipe of the second aerator is arranged at a bottom of the inner chamber of the denitrification tank;
• and an air supply pipe of the third aerator is arranged at the bottom of the supplementary reaction zone.