A flotation installation for purification of a body of water, comprising • an apparatus for generating pressurized water, • at least one relief valve, • a pressurized water line, which connects the apparatus for generating pressurized water to the at least one relief valve, • at least one buoyancy body, which is dimensioned such that the flotation installation can be arranged so as to float on the water surface of the body of water, and • a controller, which is designed to control the apparatus for generating pressurized water and optionally the at least one relief valve such that several bubbles are released, characterized by • a barrier, which at least partially encloses a surface region of the body of water and prevents contaminants conveyed to the surface at one time from spreading on the water surface beyond the barrier, and • a support structure, to which the barrier and the at least one relief valve are fastened such that the at least one relief valve is arranged below the surface region, • wherein the barrier comprises an upper edge and a lower edge, wherein, during operation of the flotation installation, the upper edge is arranged above the water surface and the lower edge is arranged below the water surface, in particular at a water depth in the range of 5 cm to 200 cm, and • wherein the at least one relief valve is located below the surface region delimited by the barrier, such that the bubbles that are generated in the vicinity of the at least one relief valve and that ascend slowly to the surface and take with them the contaminants present in the body of water arrive within the surface region delimited by the barrier. • an apparatus for generating pressurized water, • at least one relief valve, • a pressurized water line, which connects the apparatus for generating pressurized water to the at least one relief valve, • at least one buoyancy body, which is dimensioned such that the flotation installation can be arranged so as to float on the water surface of the body of water, and • a controller, which is designed to control the apparatus for generating pressurized water and optionally the at least one relief valve such that several bubbles are released, characterized by • a barrier, which at least partially encloses a surface region of the body of water and prevents contaminants conveyed to the surface at one time from spreading on the water surface beyond the barrier, and • a support structure, to which the barrier and the at least one relief valve are fastened such that the at least one relief valve is arranged below the surface region, • wherein the barrier comprises an upper edge and a lower edge, wherein, during operation of the flotation installation, the upper edge is arranged above the water surface and the lower edge is arranged below the water surface, in particular at a water depth in the range of 5 cm to 200 cm, and • wherein the at least one relief valve is located below the surface region delimited by the barrier, such that the bubbles that are generated in the vicinity of the at least one relief valve and that ascend slowly to the surface and take with them the contaminants present in the body of water arrive within the surface region delimited by the barrier.