Abstract: A cycle of filtration is realized for liquids containing solids in suspension and a rotary filter, suited to realize and cycle, where the filtration is carried out by a rotary drum fitted with a filtering surface (2), immersed in a tank containing the liquid to be filtered (26). The phase of the separation of the filtered material deposited on the filtering surface is preceeded by a phase of removal of the material from the filtering surface carried out by using air blown from a slit and it is followed by a phase of washing of the filtering surface, carried out by a plurality of sprayers.