The invention relates to an active
sludge floatation thickening device and method for a membrane
biological reaction tank process. The device is provided with a
flocculation reaction tank, a floatation tank and a
water storage tank, wherein a blender, a
sludge feeding port and a doser are arranged in the
flocculation reaction tank; the floatation tank is provided with dissolved air release regions and floatation regions separated by half weirs, a
sludge discharge trough and a sludge scraper, and a sludge collection pipeline is arranged at the bottom of the floatation tank; and the
water storage tank is connected to the back side of the floatation tank, and is provided with a level
regulator and a quick air-dissolving device. The method comprises the following steps: 1, controlling the
discharge amount of surplus sludge; 2, adding a flocculant; 3, mixing the flocculated sludge with the air-dissolved water to form adhesions; 4, regulating surface
solid loads in the floatation regions; 5, discharging clear solutions in the floatation regions; and 6, discharging the sludge. The invention is applicable to
activated sludge thickening treatment in the membrane
biological reaction tank process, and has the advantages of simple structure, reasonable design, convenient operation process and favorable effect.