Two-stage air flotation system

The utility model discloses a two-stage air flotation system which comprises an air flotation tank and a dissolved air tank, and an inner cavity of the air flotation tank is divided into a first-stageair flotation cavity and a second-stage air flotation cavity by a partition plate; a first-stage diffusion disc and a second-stage diffusion disc are arranged in the first-stage air flotation cavityand the second-stage air flotation cavity respectively, a sewage inlet pipe is connected to the top wall of the first-stage air flotation cavity, the bottom end of the sewage inlet pipe extends downwards to the middle lower portion of the first-stage air flotation cavity, and a sewage pump is arranged on the sewage inlet pipe; the dissolved air tank is connected with a water inlet pipe which is provided with a water inlet pump; the bottom of the dissolved air tank is connected with a water outlet pipe; the water outlet pipe extends into the air flotation tank and is connected with the primaryand secondary diffusion dis