Abstract: A sludge dewatering system comprising a moving foraminous belt (10) having a horizontal conveying run on which sludge is carried to permit drainage of water therefrom through the belt. In accordance with the invention a row of deflectors (12) are mounted on a pivotal cross beam (13) extending over the belt (10). Each deflector has a leading edge (19) and a pair of diverging and upwardly concave walls (21) whereby sludge proceeding along the conveying run of belt (10) is divided overturned and compressed by the deflectors.

Abstract: A penstock or sluice gate door constructed by providing a stack of steel tubes (11) preferably of rectangular cross-section, which are stitch welded together at (12). There are added welded side plates (13), a central stainless steel spindle (14) and bolts (18) for lifting equipment, and the so-formed panel is placed in a mould and encapsulated with an impervious material. If desired side and bottom sealing strips (22, 23, 21) may be integrally formed during encapsulation. The resultant door is lightweight and non-corrodible, and its strength is determined by the wall thickness of the tubes (11) which will be selected accordingly.

Abstract: A penstock or sluice gate door constructed by providing a stack of steel tubes (11) preferably of rectangular cross-section, which are stitch welded together at (12). There are added welded side plates (13), a central stainless steel spindle (14) and bolts (18) for lifting equipment, and the so-formed panel is placed in a mould and encapsulated with an impervious material. If desired side and bottom sealing strips (22, 23, 21) may be integrally formed during encapsulation. The resultant door is lightweight and non-corrodible, and its strength is determined by the wall thickness of the tubes (11) which will be selected accordingly.

Abstract: A flap valve comprising an annular frame (10) defining an opening (11) through which liquid may flow in one direction, a closure flap (14) for said opening connected to the frame (10) by a hinge member (15), and a valve seat (12) against which the closure flap (14) may close to prevent reverse flow of liquid through the opening. The frame (10) may be bolted (at 18) to a wall or pipe flange, with integral sealing ribs (24, 25) on the rear face of the frame avoiding the need for a separate gasket. The entire assembly comprising frame, closure flap, hinge, valve seat and sealing ribs, is integrally moulded from a plastics material and is reinforced where appropriate by embedded steel plates (19, 20 and 21).

Abstract: An outlet assembly for a liquid distribution system of the type whereby liquid is to be deposited onto a treatment bed (13) from one or more apertured distributor pipes (14) connected to a rotary (or linear) supply head (10) the assembly comprising longitudinally spaced apertures (15) opening upwardly in the pipe wall and clamped to the pipe over each aperture (15) a distribution tray (16) extending generally transversely but angularly from the pipe and having a generally horizontal surface (17) with upright side walls (18) so that liquid may flow upwardly through the apertures (15) and be channelled outwardly along the trays to be deposited from the outer ends thereof. The larger than usual apertures (15) ensure that no blockages occur from solids within the liquid, whilst uniform and constant distribution is ensured.

Abstract: Apparatus for dewatering sludge comprising a moving foraminous conveyor belt (10) driven in a single direction with a horizontal conveying run (11). Sludge to be dewatered is fed onto the belt at an input end of the conveying run so that liquid may drain from the sludge through the belt. Part way along the belt is disposed at least on ramp (21) having its lower edge in contact with or just above the belt surface to cause sludge to rise up the ramp thus enhancing the dewatering process. A plurality of spaced fingers (26) extend forwardly from the top of the ramp (21) thus leaving strips of the belt (20) free of sludge forwardly of the ramp and fingers.

Abstract: A valve such as penstock with a gate (13) which slides across an opening in a frame (10, 11, 12). On at least one side of the gate (13) is a two-part sealing strip consisting of resilient layer (22) and a superimposed bearing portion (23). Attached to or integral with bearing portion (23) is a thickened part (24) which limits the maximum compression of the resilient layer (22) when the valve is closed.

Abstract: This invention provides apparatus for the growth of biomass from a supply of suitable nutrient wherein the volume of biomass and the size and shape of the units in which it is present within a vessel (10) in which the reaction takes place can be accurately controlled. Control is achieved by providing a support structure (14) for the biomass comprising one or more movable bodies each of which has an internal reticular structure defining a substantial voidage therein and which essentially fills with the biomass but which does not overfill since excess growth is restricted. Restriction can be achieved by removal of excess biomass or by removal of the bodies at the time that they become filled. The techniques are capable of numerous industrial applications including various biological fermentation processes as well as the purification of sewage and industrial effluents, for example.

Abstract: This invention provides a process and apparatus for the growth of biomass from a supply of suitable nutrient wherein the volume of biomass and the size and shape of the units in which it is present within a vessel (10) in which the reaction takes place can be accurately controlled. Control is achieved by providing a support structure (14) for the biomass comprising one or more movable bodies each of which has an internal reticular structure defining a substantial voidage therein and which essentially fills with the biomass but which does not overfill since excess growth is restricted. Restriction can be achieved by removal of excess biomass or by removal of the bodies at the time that they become filled. The techniques are capable of numerous industrial applications including various biological fermentation processes as well as the purification of sewage and industrial effluents, for example.

Abstract: This invention provides apparatus for the growth of biomass from a supply of suitable nutrient wherein the volume of biomass and the size and shape of the units in which it is present within a vessel (10) in which the reaction takes place can be accurately controlled. Control is achieved by providing a support structure (14) for the biomass comprising one or more movable bodies each of which has an internal reticular structure defining a substantial voidage therein and which essentially fills with the biomass but which does not overfill since excess growth is restricted. Restriction can be achieved by removal of excess biomass or by removal of the bodies at the time that they become filled. The techniques are capable of numerous industrial applications including various biological fermentation processes as well as the purification of sewage and industrial effluents, for example.

Abstract: This invention provides a process and apparatus for the growth of biomass from a supply of suitable nutrient wherein the volume of biomass and the size and shape of the units in which it is present within a vessel (10) in which the reaction takes place can be accurately controlled. Control is achieved by providing a support structure (14) for the biomass comprising one or more movable bodies each of which has an internal reticular structure defining a substantial voidage therein and which essentially fills with the biomass but which does not overfill since excess growth is restricted. Restriction can be achieved by removal of excess biomass or by removal of the bodies at the time that they become filled. The techniques are capable of numerous industrial applications including various biological fermentation processes as well as the purification of sewage and industrial effluents, for example.

Abstract: A sludge thickening apparatus for dosing sludge with a cationic polyelectrolyte, allowing time for the development of a floc structure, placing the dosed sludge onto a surface through which liquid may drain freely by gravity in such a manner that the floc structure is retained, and removing the thickened sludge from said structure.

Abstract: Apparatus for thickening sludge comprising a driven foraminous belt (10) having a conveying surface arranged at least substantially horizontally, a chute (14) for feeding a matt of sludge onto the belt (10) at one end of the conveying run, and a plurality of parallel flexible strips (21) of material attached at one end to the output end of the chute (14) and allowed to rest freely upon the belt (10) at the other end, whereby the sludge passes onto the belt in one or more strips whose width is substantially less than that of the belt, thus to leave one or more zones of the belt free of sludge to permit drainage of water therefrom through the belt, there being a plurality of deflecting members (22) disposed downstream of the output ends of the strips (21) and adapted to deflect a portion of each strip of sludge onto the next adjacent part of the belt left free of sludge thus to produce a matt thereof of substantially uniform thickness extending across the belt.

Abstract: An aerator comprising a support member in the form of a flat plate which is adapted, when the aerator is in use, to lie in a horizontal plane and to be rotated about its central vertical axis, a plurality of angularly spaced blades secured to the underside of said plate and each extending radially from a central region thereof towards its periphery, each said blade having a maximum depth beneath a horizontal datum at a position intermediate its ends, and being provided with a plate secured to its lower edge and extending on both sides of the blade along at least a portion of that part of the length of the blade between its outer end and the position of maximum depth.

Abstract: A lifting beam comprising an elongate member carrying one or more pivotally mounted hooks for engagement of a load to be lifted, there being a balance weight pivotably mounted on the or each hook to lie on either side of the pivotal axis thereof so as to cause the hook to be biased into or from engagement with the load such that selection of the position of the balance weight enables the beam automatically to pick up or release the load when the beam is lowered on to same.

Abstract: An apparatus for separating oil from a mixture of oil and water wherein a stream of the mixture is directed along an upwardly inclined inverted channel to separate the oil from the mixture by contact of the oil with the under-surface of the channel for flow upwardly in the channel, and wherein the oil is collected from the upper longitudinal end of the channel and wherein the remainder of the stream is allowed to fall downwardly out of the channel.

Abstract: A method for treating a liquid wherein the liquid to be treated is caused to flow through a tank equipped with at least one electrode assembly in the base thereof for the generation of gas bubbles by electrolytic action, whereby suspended materials, usually but not necessarily solids, in the liquid are carried to the surface of the tank by said bubbles to form a layer of thickened material, characterised by the step of dissolving air under pressure into the liquid before it is caused to flow through said tank, whereby the amount of gas available for flotation purposes exceeds that available from the electrolytic action alone.

Abstract: A penstock comprising a frame having an opening therein and a door slidable within the frame across said opening to close same by vertical movement between fixed vertical guide members slidably engaging the side edge regions of said door, wherein at least one of said members at each side forms a resilient vertical seal, said penstock including a base invert seal which is produced by temporarily and at least partially compressing said resilient vertical seal, forming a pad of resilient material onto which the lower edge of the door in use will close and causing said resilient material to form a seal around the lower end region of the resilient vertical seal prior to releasing the temporary compressive force applied to the latter, the resilient pad being preferably formed by introducing the material in liquid form into a channel defined by limit strips such that the liquid flows around the lower end region of said resilient vertical seal to become bonded thereto, said compressive force being maintained until th

Abstract: A method of filtering a liquid comprising the steps of providing a bed of particulate material, withdrawing material from the base of the bed, supplying replacement particulate material to the bed in such a manner that the bed has a free inclined upper surface, and causing the liquid to be filtered to flow through the bed by entering the same through said inclined upper suface, and apparatus for carrying out such method. Preferably the particulate material is comprised by particles of various sizes whereby a classifying action takes place to give a structured filter bed.