Biological denitrification reactor with synchronous softening function

The utility model discloses a biological denitrification reactor with a synchronous softening function, and relates to the technical field of sewage treatment. The biological denitrification reactor with the synchronous softening function is characterized in that the upper part of the biological denitrification reactor is a straight-wall cylinder, the lower part of the biological denitrification reactor is a conical sludge hopper, a first water outlet is formed in the upper part of the straight-wall cylinder, and a first water inlet and an organic sludge reflux inlet are formed in the middle upper part of the straight-wall cylinder; an aeration inlet and a crystal nucleus feeding port are formed in the lower part of the straight-wall cylinder; an inorganic sludge discharge port is formed in the bottom of the sludge hopper; a central reaction cylinder is arranged in the straight-wall cylinder, an aeration device is arranged at the lower end in the central reaction cylinder, and the aeration device is connected