Abstract: A gasification device is described for the introduction of a gas into a liquid, in particular of air into waste water. The gasification device has a blower body element, which carries a membrane made of an elastic material with perforation slits. The gasification device also has a longitudinal ridge arranged in an area located at the top, related to the installation location. When the gas feed is switched off and the hydrostatic pressure of the waste water is imposed, an axial fold of the membrane is formed in this upper area. This area is, at the same time, free of perforation slits.