Abstract: Improved devices for filtration of fluid suspensions that form flow resistant filter cakes, e.g., waste-water treatment sludges, have a cylindrical filter unit mounted for rotation about an approximately horizontal axis. Influent is charged in one end, filter cake forms on an inner rigid filter media surface and discharges at the other end. Pressurized air is applied along a top, longitudinal area and vacuum assist is applied along a bottom longitudinal area of the rotating filter unit. In preferred embodiments, the cylindrical unit is formed of wire spirally wound into a cylinder with spaces therebetween, there are a plurality of spaced apart bars fixed normal to the helical wire on the inner surface and rigid filter media formed of particulate material bonded in a resin matrix fills the cavities between the bars and covers the wire spirals.

Abstract: Filter units for use in filtering liquid suspensions of material prone to form a filter cake resistant to continued flow of filtrate therethrough, e.g., wastewater treatment sludge, have a pair of planar sides arranged in a V-shape. Such sides are formed of rigid filter media, e.g., porous sheets of granular material bound in a resin matrix. Suspension to be filtered is charged into the trough and filtrate is drawn by vacuum through its porous sides. A plurality of such units are arranged side-by-side about a common center in a cylindrical assembly which can be rotated about such center at a predetermined rate to permit each unit to pass through a series of filtering steps to provide new filtering methods.

Abstract: Modules for use in forming rigid filter beds by laying a plurality of the modules side-by-side upon a flat base are in the form of porous, planar elements having a continuous, polygonal upper surface, a continuous lower surface approximately coterminous to the upper surface, and sides normal to said surfaces of substantially equal depth much shorter than their length, such elements comprising laminated layers, each layer being formed of particulate material of substantially uniform size rigidly fixed together in a matrix of cured binder, the particles of the layers being substantially different in size than the particles of the adjacent layers, the top surface being flat and the bottom surface being channelled. In preferred forms, the modules' surfaces are square, there are only a top layer and a bottom layer, the top layer is much thinner than the bottom layer and the particles in the top layer are appreciably smaller than the bottom layer particles.

Abstract: Filter elements are constructed of an array of parallel, spaced-apart rods, a plurality of spaced-apart bars fixed normal to the rods on one side of the array forming a multitude of cavities between the bars and above the surface of the array. Filter media comprising crushed aggregate bound in a matrix of cured resin fills the cavities to just below the plane of the top edge of the bars.Filter apparatus is provided having a rigid filter bed and including a scraper blade to be moved above the filter bed in contact with the top surface thereof to lift portions of filter cake from the filter bed. The scraper blade includes means to apply a vacuum through a surface of the blade.A new filtering method applies vacuum to the portions of filter cake lifted by the scraper blade causing relatively rapid removal of filtrate therefrom and producing an incoherent mass of particles of relatively dry filtered material.

Abstract: Filter media comprises a grid of parallelogram openings formed by a first series of parallel strips and a second series of parallel strips narrower than the first series strips fixed together normal to each other. The grid openings are filled with rigid porous filter material formed of crushed anthracite or other solid particles held in a matrix of cured resin presenting a flat upper surface together with the upper edges of the first and second series strips.Filter apparatus are formed by placing the filter media in an open-top tank on or above the floor of the tank and providing one or more conduits in the tank through which liquid contained in the tank below the level of said filter material can be withdrawn from the tank.

Abstract: Filter apparatus for removing fine solids from aqueous effluents, e.g. waste water filtration, comprises horizontal upper and lower rigid filter plates formed of aggregate fixed in a matrix of cured organic resin defining therebetween a secondary filter zone containing loose filter media, first and second fluid confining chambers above and below said filter plates respectively from which liquid can flow through the filter plates, a vertical conduit for conducting liquid from beneath the lower filter plate for discharge into the first chamber through an opening in the upper filter plate, conduits for inlet and outlet of liquid to said secondary filter zone and second chamber and a sparger to spray wash water on the top surface of the upper filter plate. In a filtering mode, the liquid suspension to be filtered flows into the first chamber via said vertical conduit and then passes, in turn, through the upper filter plate, the filter zone, the lower filter plate and the second chamber to discharge therefrom.

Abstract: Filter apparatus for removing fine solids from aqueous effluents, e.g., waste water filtration, comprises horizontal upper and lower rigid filter plates formed of aggregate fixed in a matrix of cured organic resin defining therebetween a secondary filter zone containing loose filter media, first and second fluid confining chambers above and below said filter plates respectively from which liquid can flow through the filter plates, a vertical conduit for conducting liquid from beneath the lower filter plate for discharge into the first chamber through an opening in the upper filter plate, conduits for inlet and outlet of liquid to said secondary filter zone and second chamber and a sparger to spray wash water on the top surface of the upper filter plate. In a filtering mode, the liquid suspension to be filtered flows into the first chamber via said vertical conduit and then passes, in turn, through the upper filter plate, the filter zone, the lower filter plate and the second chamber to discharge therefrom.

Abstract: An aeration system comprising a long resilient plastic tube having a plurality of aeration slit valves therein, a control means connected about the outside of said tube to control the size of the aeration slit valve openings when the tubing is under pressure, and a second tube encompassing the first tube and the control means. The second tube also includes a plurality of slit or perforated type openings therein. Said aeration system providing a non-floating, weighted aeration system having a controlled aeration flow of air out through the slits in said tubing system along length of system and may include a smooth outer diameter surface to prevent material from snagging on said tubing system when placed in a sewage system.