Sewage treatment system

The utility model relates to a sewage treatment system which comprises a flocculation zone, a settling zone, a first pipeline and a second pipeline, the first pipeline is arranged at the bottom of the flocculation zone and is constructed to be of an annular structure arranged on the outer side of a guide cylinder in a surrounding mode, and a liquid inlet hole used for sucking a mud-water mixture is formed in the bottom of the first pipeline; a communicating pipeline is arranged on one side, close to the settling zone, of the first pipeline; the communicating pipeline is configured to be used for conveying the mud-water mixture in the first pipeline to the settling zone; the second pipeline is arranged at the bottom of the flocculation area and is constructed to extend to the position close to the corner of the flocculation area along the outer side of the first pipeline, a sludge suction hole is formed in the bottom of the second pipeline, and the second pipeline is configured to be used for discharging sludg