Sewage treatment method suitable for upgrading and reconstruction of sewage plant

The invention relates to a sewage treatment method suitable for upgrading and reconstruction of a sewage plant. The method comprises an original process of the sewage treatment plant and an efficientsedimentation tank and vertical fiber filter cloth filter combined process added between a sedimentation tank B and a disinfection tank of the original process, wherein the original process is based on water inlet, coarse screen, fine screen, sedimentation tank A, biochemical reaction tank, sedimentation tank B, disinfection tank and water outlet; an efficient sedimentation tank comprises a firstmixing tank, a second sedimentation tank and a water detector; 10-18 mg/L of an iron chloride and ferrous chloride mixture reagent is added to the first mixing tank to react with sewage with stirring;the sewage stays in the first mixing tank for 3-4 min. With the adoption of the sewage treatment method suitable for upgrading and reconstruction of the sewage plant, two problems of phosphorus removal and suspended solid remo