Continuous filtration under pressure is obtained by combination of a looped filter belt and an alveolar belt which are caused to cooperate with a rotary distributor drum. The belts are compressed against the drum through application onto the belts of an external pressure which is at least equal to the filtration pressure but which is exerted on a surface which is larger than that onto which the filtration pressure is exerted.

A continuous filtration/separation apparatus with a part of the casing of a vane pump constructed of a filter so that material to be treated which is introduced between the casing and the vane adjacent to the rotor can be dehydrated. The endless filter of the vane pump at one portion faces the rotor of the casing and moves successively. The vane pump also has a washing device for washing the other portion of the endless filter which does not face the rotor, to eliminate clogging of the filter. A support supports an arc portion facing the rotor of the casing, which arc portion is rotatable about a center which is eccentric relative to the center of rotation of the rotor, so that the dehydrating ratio can be adjusted. A drive rotates the arc portion about its center for adjustment of the dehydration ratio.

Dry and liquid feed supplements are recovered from treating animal wastes collected from a confinement feeding area for livestock and the like by a closed loop type of collection system including a primary liquid storage tank. Solids and liquids are separated from the collected wastes by dynamic liquid filtering apparatus including a unique compression filter. Liquid is withdrawn near the surface of the primary tank, passed through a second solid/liquid separating filter and transferred to a secondary tank. Preferably rarified oxygen is forced into both tanks so as to aerate the liquids. After appropriate aerobic digestion or oxidation, the secondary tank liquids are used to supplement feed water and the solids are used to supplement dry feed ration.

An apparatus for thickening and extracting the liquid from a sludge comprises a sludge-thickening assembly wherein solid matters in the sludge are coagulated to form coagulated flocs and the floc sludge is separated and thickened, and an assembly for extracting liquid from said floc sludge under pressure to obtain a dehydrated cake. The sludge-thickening assembly comprises coagulation means for the sludge, a first and a second screen rolls having a reticulate material covering the outer surface; and the assembly for extracting the liquid comprises an endless moving flocked filter belt, means for supporting the belt, a cylinder forced to closely contact with an upper portion of said endless moving flocked filter belt, and at least one press roll urging said endless moving flocked filter belt against said cylinder.

The invention concerns a device for filtration under pressure making use of the combined actions of a looped band, a filter cloth and a distributing drum on a portion of the periphery of said drum which is covered by a compartmented region of said band, with a sealing effect provided by application of an external pressure upon said band. The devices is organized to perform filtration while the drum, a sequence of compartmented elements and filter cloth are stationary, while the filter is caused to open by the placing in rotation and rotary travel of at least said drum and said filter cloth. Each compartment may be provided with a grooved bottom for collection of the filtered liquid, passing through a corresponding filter cloth, with the corresponding drum surface being itself provided with grooves covered by a second filter cloth driven by said drum and traversed by incoming liquid to be filtered. The invention provides an improvement in filtration efficiency and a simplification of filter construction.