A device for dewatering liquids and thin sludges has a conveyor belt (20), a ripening chamber (30) and means for supplying the liquid or sludge (60) and adding a flocculating polyelectrolyte (62) into the ripening chamber. All these elements are accommodated in a single vat, which acts therefore as a housing and lateral enclosure. Displaceable, turbulence-generating guiding and baffle plates (31) in the supply region ensure a good and thorough mixture, allowing the length of the mixing path and therefore the ripening time to be varied.
