Abstract: An apparatus for cleaning and aeration of open bodies of water includes a floating structure partially extending above a water surface and having at least one opening in its lower region through which, water flows into the apparatus, and a fan arranged in the upper region of the floating structure for creating vacuum that enables flow of water inside of the floating structure. An air receiving space is defined inside of the floating structure. A perforated plate which is located below a water surface established in the floating structure, limits the air receiving space from above. The air receiving space is connected with atmosphere by a gas conducting conduit.

Abstract: An arrangement for driving out volatile impurities from a ground water with a well shaft extending to the region of the ground water to be purified, the arrangement comprises an element for producing a negative pressure in the well shaft and supplying a gas underneath a water level in the well shaft, an element for providing a plurality of capillary openings in an upper sieve wall portion of the well shaft at least in a purification region between a gas inlet and a water level in the well shaft to enhance a laminary flow of ground water with relatively high speed, the capillary openings forming a greater free throughflow surface than a remaining portion of the well shaft.

Abstract: To expel volatile contaminants from a liquid body, outer air is introduced into a perforated container arranged below the liquid surface and having an open bottom by the action of a suction blower creating an underpressure above the liquid surface. Air bubbles exiting through the perforated top wall of the container entrain the volatile contaminants and expel the same into the underpressure area. The air receiving perforated container is either suspended on a float or fixedly arranged relative to the bottom of the receptacle.

Abstract: Driving of volatile impurities from a ground by mans of air is performed by aspirating an afterflow air and impurities containing gases which penetrated through a permeable wall of a shaft in a ground, at one or several locations in regions of expected high gas contents, air afterflow passages are extended to these regions for supplying the afterflow air, and an adjustable afterflow resistance is arranged in the passages for influencing a negative pressure value and a flow speed in these regions.