Sewage treatment device for adjusting carbon-nitrogen ratio by utilizing external bypass system

The invention discloses a sewage treatment device for adjusting a carbon-nitrogen ratio by utilizing an external bypass system, and belongs to the technical field of sewage treatment equipment. The device comprises a regulating tank, an anoxic tank, an aerobic tank, a sedimentation tank and a disinfection unit, wherein the regulating tank is connected into the anoxic tank through a water pump, overflow of the anoxic tank is connected into the aerobic tank, overflow of the aerobic tank is connected into the sedimentation tank, the sedimentation tank is connected into the disinfection unit, thedevice further comprises an SBR reaction tank, the water inlet end of the SBR reaction tank is connected with the water outlet end of the regulating tank through a water pump, and the water outlet endof the SBR reaction tank is connected into the aerobic tank through a water pump. By adjusting the bypass flow ratio of the bypass part of the SBR reaction tank, the aeration-sedimentation time of the SBR reaction tank is cha