MBR (Membrane Bioreactor) membrane on-line cleaning device and sewage treatment system

The utility model discloses an MBR membrane online cleaning device and a sewage treatment system, and belongs to the technical field of sewage treatment. The utility model relates to an MBR (Membrane Bioreactor) membrane on-line cleaning device, which is used for cleaning an MBR membrane in a membrane pool and comprises a gas-liquid mixing tank and at least one flushing piece, the gas-liquid mixing tank is provided with a mixing cavity, a liquid inlet, a gas inlet and a mixed liquid outlet, the liquid inlet, the gas inlet and the mixed liquid outlet are communicated with the mixing cavity, the liquid inlet is used for being communicated with the membrane pool, and the gas inlet is used for being communicated with a gas source. The flushing part is provided with a flushing part inlet and a plurality of flushing part outlets arranged at intervals, the flushing part inlet is communicated with the mixed liquid outlet, and the flushing part outlets face the MBR membrane. According to the on-line cleaning device fo