An apparatus for filtering liquids, especially for recovering fibres from white water, includes rotatable filter discs (5) at least partly immersed in the liquid to be filtered, and a shaft wall connected to the discs and forming a circular cylindrical filtrate chamber, which extends centrally through the discs. A rigid stationary partition wall (19) extends in the filtrate chamber dividing the latter into at least two axial channels (20, 21). The partition wall (19) is spaced from the shaft wall and arranged, such that all of said axial channels receive various fractions of filtrate, respectively. Filtrate discharge means is provided for discharging said fractions of filtrate separately from the respective axial channels, such that the pressure prevailing in the filtrate of each channel is at least substantially as high as atmospheric pressure.