Device for advanced nitrogen and phosphorus removal in sewage treatment

A device for advanced nitrogen and phosphorus removal in sewage treatment includes a pre-denitrification zone, an anaerobic zone, an anoxic zone, an aerobic zone, a sedimentation zone, a biological filtration zone, and a clear water zone, where a sludge return system is provided between the pre-denitrification zone and the sedimentation zone; a nitrification liquid return system is provided between the anoxic zone and the aerobic zone; a filler layer is provided in the biological filtration zone, and the filler layer divides a cavity in the biological filtration zone to form an upper water inlet cavity and a lower water outlet cavity; a backwash aeration pipe is provided in the water outlet cavity, and a backwash water outlet is formed in the water inlet cavity; and the backwash water outlet is connected to a sludge concentration and storage tank or the pre-denitrification zone.