NOVELTY - Aerobic denitrification reactor comprises a closed reactor, whose bottom is provided with an aeration head. A water inlet pipe and a water outlet pipe are respectively set on the upper and lower sides of the reactor. The reactor is provided with a biomass carrier. The biomass carrier is mycelial pellet. A mycelial pellet biofilm is obtained from aerobic denitrifying bacteria.    USE - Used as an aerobic denitrification reactor.    ADVANTAGE - The reactor: allows the nitrifying bacteria and denitrifying bacteria under aerobic conditions in the whole cycle, promotes good growth and reproduction, simultaneously achieves a stable nitrification and denitrification effect; can solve the problem of weak competitiveness of aerobic denitrifying bacteria within the system and difficult to form the dominant flora resulting in the huge loss; and ensures long-term stable operation within a short cycle.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for denitrification operation method of the reactor, comprising (a) preparing mycelial pellet as a carrier by: adopting mycelial pellet preparation and aerobic denitrifying bacteria biofilm device, adding mycelial pellet medium and mycelial pellet spore suspension, placing in a shaker, and culturing at 30 degrees C under a speed of 135-145 rotations/minute for 36-48 hours to obtain mycelial pellet; where the mycelial pellet spore is taken from Aspergillus niger Y3 (CGMCC No. 3.3926); the mycelial pellet medium comprises 10 g/l glucose, 1 g/l ammonium chloride, 1 g/l potassium dihydrogen phosphate trihydrate and 0.5 g/l magnesium sulfate heptahydrate; and the addition proportion of mycelial pellet medium and mycelial pellet spore suspension is calculated according to the following formula: the mycelial pellets spore suspension inoculum volume (ml) is equal to 0.25x 0.1%x mycelial pellet medium volume (ml)/A620, where A620 is the absorbance of mycelium pellet spore suspension at 620 nm wavelength; (b) preparing aerobic denitrifying bacteria biofilm by: discarding the supernatant obtained in step (a), adding aerobic denitrifying bacterial medium into mycelial pellet preparation and aerobic denitrifying bacteria biofilm device, inoculating10-15% aerobic denitrifying bacterial liquid, carrying out continuous aeration culturing under a dissolved oxygen content of 3 mg/l plus minus 0.2, taking 9-10 hours as a reaction cycle, and after three cycles of culturing obtaining the biofilm, where the aerobic denitrifying bacteria in the bacterial liquid is Heilongjiang Province Key Laboratory of Biotechnology screened Pseudomonas stutzeri T13 (CGMCC No. 6182), the aerobic denitrifying bacterial medium comprises 4.7 g/l sodium succinate, 7.9 g/l sodium dihydrogen phosphate heptahydrate, 0.1 g/l magnesium sulfate heptahydrate, 1.5 g/l potassium nitrate, 0.3 g/l ammonium chloride, 1.5 g/l potassium dihydrogen phosphate and 2 ml/l trace elements, and the trace elements comprises 50 g/l EDTA, 2.2 g/l zinc sulfate, 5.5 g/l calcium chloride, 5.06 g/l manganese chloride tetrahydrate, 5 g/l ferrous sulfate heptahydrate, 1.1 g/l ammonium molybdate tetrahydrate, 1.57 g/l copper sulfate pentahydrate and 1.61 g/l cobalt chloride hexahydrate; and (c) adding an activated sludge into the reactor, injecting the aerobic denitrifying bacteria mycelial pellets attached to the mycelial pellet preparation and aerobic denitrifying bacteria biofilm device, opening the water inlet, starting the reactor to operate, continuously operating the reactor under aerobic condition, and controlling the dissolved oxygen content up to 3 mg/l plus minus 0.2, temperature at 30 degrees C plus minus 2 degrees C and the pH of the liquid to 7-7.5, where the reactor adopts intermittent water inlet, and the reaction period is 9-10 hours.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic representation of the aerobic denitrification reactor.