Abstract: A method of and an apparatus for separating a liquid medium in different components by gravity in a manner that a medium to be separated is set in slow rotating motion (2) with the axis of rotation substantially vertical, so that the heavier component concentrates in the bottom section of a slow-moving vortex and the lighter component concentrates in the top section of a slow-moving vortex (2). For a more pronounced separation activity and simpler equipment, two or more slow-moving vortexes (2) are contacted with each other in horizontal direction. The outer sections of various settling basins (1) are in contact with each other by way of a gate or channel (40). Various sub-basins (1) can be connected in series or in parallel.