Mixing and aerating apparatus and method for mixing and aerating

The invention concerns a mixing and aeration device (4) and a method for mixing and aerating a liquid, in particular water mass in a tank (1) of a liquid treatment device, in particular water treatment device, with a mixing and aeration unit (3) having a first housing part (6) and a second housing part (7) complete the housing (5), arranged one in the first housing part (6) electric motor (11), one extending through the first and second housing part shaft 12 at a first shaft end (14) of the electric motor (11) about a rotational axis (a) is driven in rotation, an opposite with the first shaft end (14) the second shaft end (21) connected to the hub (34), arranged at least two on the hub (34) vanes (42) and to the housing (5) connected to the air supply pipe (46). adjacent to a joint (8) of the first (6) and second housing part (7), the first housing part (6) on a connection device (44) with an in radial direction with respect to the axis of rotation (A) extending opening (45). On the connecting device (44) an air supply pipe (46) is connected.