A standing wave in a water current, which is subject to purification, is swirled in the lower mass-exchange chamber in order to create negative pressure along the central axis, the atmosphere air intake and crating of two countercurrents interacting with each other, resulting in a standing wave and oxygenation of the water current. A cylindrical mixing chamber, which is divided into the upper mass-exchange chamber and the lower mass-exchange chamber by dividing walls with a coaxial orifice towards the air-supply pipe and peripheral bypass channel. In the lower mass-exchange chamber, water, which is subject to purification, is swirled and under the negative pressure in the center it intakes air from the air-supply pipe, creating hydrosol and reaction area of ion exchange due to forming of the standing acoustic wave. Part of the processed current is outlet into the volume through a permeable wall in the side surface of the upper mass-exchange chamber. In the volume there is at least one cylindrical mixing chamber. In the lower part of the volume there are branch pipes for outputting undissolved impurities and clean water. In the upper part of the volume there is a branch pipe for outputting spent air.