An aeration rotor is movable on a given path above the surface of the water. The aeration rotor, which is carried by floats, is guided along the path and driven by current produced by it in the water. Specif. the rotor is guided so that the angle between the direction of its movement and the direction of the horizontal current which it generate deviates from 180 degrees. The guide elements esp. comprise a connection resisting the traction of the rotor, with a fixed anchorage point, or with a longitudinal guiding system.
