Shield tunneling machine sewage treatment device in shield tunneling construction of subway tunnel

A shield tunneling machine sewage treatment device in the shield tunneling construction of a subway tunnel comprises a pneumatic diaphragm pump arranged at the shield tail portion of a shield tunneling machine. The water inlet opening end of the pneumatic diaphragm pump is placed into shield tail sewage through a pipeline, and the water outlet end of the pneumatic diaphragm pump is placed into a sewage tank of a fifth section of trolley. The sewage tank is of a three-level settling pond structure, a stirring rod is arranged in a first-level settling pond, and a punching mesh plate is mounted between the first-level settling pond and a second-level settling pond. The output end of a third-level settling pond is connected with a filter pump through a valve, and the output end of the filter pump is connected with a bentonite tank which is placed on a second section of trolley. Filtered sewage and bentonite are completely mixed and expanded in the bentonite tank, then the bentonite is conveyed to a shield excavation tunnel face, a soil bin and a screw machine through a bentonite extrusion pump via a tunnel face pipeline, a soil bin pipeline and a screw machine pipeline, and muck is improved. The problems of sewage treatment and recycling in the shield tunneling construction of the subway tunnel are solved, the shield tunneling machine sewage treatment device has the advantages of being simple in structure and low in cost, and construction water is saved while the sewage is reused.