Abstract: A sludge removal apparatus for a clarifier/thickener tank includes a central rotatable or stationary sealed sludge collection box submerged in the tank and surrounding a vertical, central influent column or support shaft. The collection box is positioned at any elevation between the tank bottom to a position just below the liquid/air level in the tank. At least one rotatable rake arm, preferably one or two pairs of spaced rake arms each having a spiral blade, is affixed to and rotates with the box and a driving cage, to inwardly push or pick-up sludge at the tank bottom for transport to the collection box. A substantially controlled flow of sludge may be provided into the collection box by valved or adjustable gate control through a sidewall opening in the collection box.

Abstract: A sludge removal apparatus for a clarifier tank includes a rotatable or stationary sealed sludge collection box submerged in the tank and surrounding a vertical, central influent column. The collection box is positioned at any elevation between the tank bottom to a position just below the liquid/solids level in the tank. A rotatable rake arm or pick-up pipe or sludge collection duct may be affixed to and rotates with the box and a driving cage to push or pick-up sludge at the tank bottom for transport to the collection box. A substantially constant flow of sludge may be provided in the collection box by valved or adjustable orifice control over the flow of sludge from the pick-up pipe(s) or duct(s) or center tank cone. A fixed flanged manifold spool with spaced branches is positioned between flanged vertical sections of the center column and sludge is transported from the collection box through the branches to a concentric sludge withdrawal pipe extending downwardly within the center column.

Abstract: The invention comprises an improvement in a cleaning apparatus particularly useful for filters. A mechanism drives a hood into position adjacent partitions. A sealing member is selectively actuated to seal off at least one such compartment for cleaning while the remainder of the filter remains in service. Sealing is accomplished by interaction between the hood and the partitions. The invention also relates to techniques for selectively bringing the hood into contact with the partitions, and a construction of the hood and a media support plate which allows flexibility to lilft and scour the filter media using a gas to dislodge impurities, coupled with a liquid backwash involving drawing filtered water back through the media to carry away the impurities out of the filter.