Water retaining structure of sewage treatment tank

The utility model discloses a stagnant water structure of a sewage treatment tank, the stagnant water structure comprises an anaerobic tank, a water passing port, a plug flow device and a filler, a plurality of partition walls are arranged in the anaerobic tank to divide the anaerobic tank into a plurality of anaerobic treatment units, the water passing port is arranged on one end of the partition wall close to the tank wall of the anaerobic tank, and the plug flow device is arranged on the filler. The water passing openings in the adjacent partition walls are oppositely arranged, the plug flow equipment is mounted in each anaerobic treatment unit, and the filler is uniformly arranged at the bottom of each anaerobic treatment unit; a water inlet is formed in one end, opposite to the water passing opening, of the anaerobic treatment unit on one side of the anaerobic tank, a water outlet is formed in one end, opposite to the water passing opening, of the anaerobic treatment unit on the other side of the anaerob