The oxygen saturation of water for various uses - water treatment for communal and industrial needs, waste effluent treatment, biological self-cleaning in reservoirs and in streams, etc. - is an important step in water improvement technology. For that purpose, various methods and variously designed mechanical and pneumatic aerators are used in practice. A high-efficiency vortical aerator has been designed the MGSU. Operation of this aerator is based on the interaction of two coaxial circular flows rotating in opposite directions. © 2003 Plenum Publishing Corporation.