Abstract: Within a chamber having an inlet for admitting a sludgy substance for dewatering and an outlet for discharging the dewatered cake of the sludgy substance, there are disposed two laterally opposed filtration trains each consisting of a plurality of rotary filter elements which are each formed of a multiplicity of circular plates arranged face to face in the axial direction at fixed intervals and which are so disposed that they intermesh so as to permit the circular plates of each rotary filter element to partially enter the corresponding spaces between the circular plates of the adjacent rotary filter elements.

Abstract: Disclosed herein is a method for cleaning a filter device packed with a bed of filtering grains, which cleaning is effected whenever the pressure loss in the filter device has increased to a prescribed level by first discharging the filtering grains through the upper side of the device in conjunction with a current of water, then circulating the filtering grains back into the device via the lower side thereof and giving the freshly formed bed of filtering grains a backwashing with water.

Abstract: Disclosed are improvements in and relating to a fluidized-bed type multistage solid-liquid contact apparatus which comprises a contact column incorporating therein a multiplicity of a spaced and horizontal support plates each carrying thereon a fluidized bed of solid particles and having a downcomer for communicating between the upper and lower sides of the plate, a storage tank for the liquid to be treated by contact with said layer of fluidized solid particles in said contact column, a storage tank for receiving the treated liquid and a storage tank for solid particles for use in said layers.