Abstract: To equalize the precoat application over the length of the filter press and/or over the height of each filter cloth, the drainage of at least a part of the carrier medium occurs at at least one, and preferably at a plurality of regularly distributed, drainage points located between the ends of the filter press, and preferably at a throttled rate, so that a pressure is built up in the filter chambers. At least one filter plate, and preferably a plurality of filter plates arranged at regular intervals, is provided with additional drainage orifices for the carrier medium at the upper end thereof with such additional drainage orifices being connected by flexible hoses to one or more filtrate-collecting pipes. The total cross-sectional area of all of these additional drainage orifices is smaller than the total cross-sectional area of the filtrate drainage channels used during filtration.

Abstract: Scraper apparatus for settling basins embodies a translatable bridge which is mounted above the basin and carries a pivot arm and a loading device that generates a return force for loading a scraper blade carried by the pivot arm into the scraping position. The loading device generates a return force which initially increases during upward pivotal movement of the scraper blade.

Abstract: A plate-type filter press having a cleaning truck movable in the direction of movement of the slidable filter plates embodies a drive and a pusher adapted to be brought into engagement with the filter plates. The cleaning truck has a releasable brake and the pusher is extensible by the drive in the direction of movement of the filter plates.

Abstract: A boom is mounted for pivotal movement about the center from which the arcuate shape of a filter screen is struck and a cleaner is pivoted to the free end of the boom. A single reversible drive unit is operatively connected to the cleaner for exerting a force thereto to tilt the cleaner toward a cleaning position. A stop operatively and rigidly connects the cleaner to the boom to transmit force from the cleaner to the boom as a pivotal force only after the cleaner is tilted to the cleaning position to thus rigidly connect the drive unit and cleaner to the boom.

Abstract: A bar screen with a screen cleaner has a vertically movable carriage with a rake pivotally connected thereto by pivot arms. A foldable lever assembly is pivotally connected to the carriage and to the pivot arms and assures a fully extended position and a folded position which correspond to a position of engagement of the rake with the screen and a position of disengagement of the rake with the screen, respectively. A lower stop engages the foldable lever assembly and moves it from a folded position to an intermediate folded position at the end of downward movement of the carriage and before the lever assembly reaches fully extended position so that the rake remains in a position of disengagement with the screen during downward movement of the carriage and is held in this position until the lever assembly is moved to fully extended position in response to upward movement of the carriage.

Abstract: A process and apparatus for the chemical-mechanical treatment and purification of ground and surface waters and effluents of various types employs adding materials for coagulation, flocculation, precipitation, sedimentation and altering the pH value. The process comprises separate process stages carried out successively as follows: (1) a first initial process stage wherein certain additives are admixed to the raw water by stirring; (2) a second initial process stage wherein contact sludge is admixed by stirring; (3) a third initial process stage wherein a flocculent aid and possibly also at least some of the other materials added in the first stage are admixed by stirring with high energy input; and alternatively (4) a fourth initial process stage for the formation of course flocs and completion of reaction of the previously added materials and formation of settleable particles and conglomerations of particles together with adsorbed and attached and occluded raw water components with moderate movement.

Abstract: A sludge de-watering plant has a plurality of filter presses connected in parallel with at least two low-pressure pumps delivering a high rate of sludge for rapid filling of the presses and at least two high-pressure pumps substantially effecting the filtration. A particular pipe system is associated with each of the low-pressure and high-pressure pumps with the pipe systems being connected to the individual filter presses for mutually independent delivery. Control means mutually controls the pumps in the two pipe systems independently by the relevant pressure in the pipe systems.

Abstract: Apparatus for extracting liquid from a suspension includes a horizontally mounted rotatable filter media covered concentrator drum with an inner drum rotatable about a horizontal axis within the concentrator drum and defining a suspension transition chamber therebetween. The drums are mounted in a common frame and are rotated in opposite directions with the suspension being introduced at one end of the transition chamber. Angularly disposed vanes on the outer surface of the inner drum convey the suspension through the transition chamber and turn and lift the suspension to a maximum elevation below the top of the transition chamber with the suspension falling back before reaching the top of the transition chamber. The filter media is cleaned as it moves at an elevation above the suspension.

Abstract: A process and apparatus for the batch-wise filtering of a sludge-like material in which the discharge period of the filter press is used for filling a pressure vessel containing air with a pump being also used during this period. During the filtration period the pump can operate solely for feeding the filter press to thereby increase the filtration capacity and reduce the required filtration period. During the discharge period the pump also operates exclusively for feeding the pressure vessel to further speed up the process. The pump can operate continuously and the different steps of the process can be controlled by only opening and closing control valves.

Abstract: A process and apparatus for treating wastewater with oxygen in which the wastewater is circulated on a horizontal course and is exposed to the introduction of oxygen or oxygen-enriched air in one or several sections of its course whereas it is exposed to the atmosphere on the remainder of its course. Oxygen of a higher concentration than atmospheric oxygen is contacted at least intermittently with the water surface and introduced into the wastewater through agitation of the water surface. At least a part of the total volume of the wastewater is treated by carrying out alternately at least two of the following three modes of operation: (a) surface aeration of the wastewater using atmospheric air; (b) oxygenation while maintaining atmospheric pressure above the wastewater; and (c) oxygenation while maintaining positive pressure above the wastewater with the operating modes alternating with each other in response to variations in the volume and/or character of the wastewater being treated.

Abstract: A pump for conveying waste water and the like embodying a substantially vertically arranged drivable screw mounted for rotation within a fixed pipe having an inlet at the lower end thereof and an outlet at the upper end thereof. At least one upstanding baffle is mounted below the screw and in the vicinity of the inlet with at least the upper portion of the baffle extending in the direction of conveyance.

Abstract: This invention relates to apparatus for continuously discharging liquid from a container, such as a waste water tank having a discharge pipe with an inlet located adjacent the container floor and an outlet located outwardly of the container. The liquid flow is controlled by a control unit which operates as a function of the liquid level in the container. The discharge pipe has a riser section between its inlet and its outlet which extends upwardly to an apex section to define an overflow for the liquid. The riser section is adjustable in height which is controlled by control means that always maintains the overflow at a constant elevation below the liquid level in the container.

Abstract: Apparatus for separating liquid and/or solid particles suspended in a gaseous and/or vaporous media stream centrifugally has a curved channel through which the media stream flows. A turbulence chamber is connected to the concave side of the curved channel and accommodates a partial stream of the media stream and has at least one discharge opening for particles separated from the partial stream and at least one exhaust opening for the particle free fraction of the partial stream. At least one of the walls of the curved channel and the turbulence chamber has a cavity for the passage of a heat transfer medium.

Abstract: Liquid to be treated flows into a combined sedimentation and thickening tank. The upper part of this tank is a sedimentation zone in which the liquid passes through parallel flow paths between downwardly inclined separator plates below which the solids fall to the bottom of the tank into the thickening zone whereat the solids are stirred and removed by a suitable stirring and scraping device. The liquids flowing with the solids through the parallel paths are removed at the end of said paths and delivered directly to the top of the sedimentation zone thus leaving the thickening zone essentially flow-free. Flocculants may be added to the water to be treated in a separate flocculation compartment arranged upstream from the sedimentation compartment. A separate destabilization compartment may be provided upstream from the flocculation compartment. A square sedimentation zone may merge smoothly into a circular thickening zone. The thickening zone may extend beneath the flocculation compartment for compactness.

Abstract: A process for treating wastewater with oxygen in which oxygen of a higher concentration than atmospheric oxygen is contacted at least intermittently with the water surface and introduced into the wastewater through agitation of the water surface. At least a part of the total volume of the wastewater is treated by carrying out alternately at least two of the following three modes of operation: (a) surface aeration of the wastewater using atmospheric air; (b) oxygenation while maintaining atmospheric pressure above the wastewater; and (c) oxygenation while maintaining positive pressure above the wastewater with the operating modes alternating with each other in response to variations in the volume and/or character of the wastewater being treated. The wastewater is circulated on a horizontal course and is exposed to the introduction of oxygen or oxygen-enriched air in one or several sections of its course whereas it is exposed to the atmosphere on the remainder of its course.

Abstract: A chamber filter press embodying movable filter plates suspended for movement along horizontal guides by an endless transporting assembly driven by a reversible motor and carrying dogging members which cooperate with cams on the filter plates as the press is opened. A switch connected to a time control device reverses the motor when the filter plate which has just been moved rests against the previously moved filter plate and at the end of a preset time the time control device switches the motor from reverse to forward motion. The motor is stopped by a limit switch which is operated by a dogging member at the end of a preset time after the last filter plate has been moved forward.

Abstract: Apparatus for conveying and dewatering wet coarse screenings debris comprises a drag chain conveyor having a conveying flight. A pressing unit is mounted above the conveying flight and exerts a downward pressure on the debris. A trough having a perforated bottom is mounted beneath the conveying flight in the vicinity of the pressing unit.

Abstract: Water having calcium compounds therein is softened by admixing an alkaline precipitating agent and finely divided crystalline calcium carbonate therewith in a mixing zone prior to the addition of a flocculating agent containing trivalent metal ions whereupon the calcium compounds are then changed inside a reaction zone into calcium carbonate. At least a part of the calcium carbonate newly precipitated from the water in the reaction zone prior to addition of the flocculation agent is immediately withdrawn and recycled to the mixing zone.

Abstract: Liquid to be treated flows into a combined sedimentation and thickening tank. The upper part of this tank is a sedimentation zone in which the liquid passes through parallel flow paths between downwardly inclined separator plates below which the solids fall to the bottom of the tank into the thickening zone whereat the solids are stirred and removed by a suitable stirring and scraping device. The liquids flowing with the solids through the parallel paths are removed at the end of said paths and delivered directly to the top of the sedimentation zone thus leaving the thickening zone essentially flow-free. Flocculants may be added to the water to be treated in a separate flocculation compartment arranged upstream from the sedimentation compartment. A separate destabilization compartment may be provided upstream from the flocculation compartment. A square sedimentation zone may merge smoothly into a circular thickening zone. The thickening zone may extend beneath the flocculation compartment for compactness.

Abstract: A transport device for displacement of filter plates embodying a transport pawl pivotally mounted on a drawing element disposed to move the plates in the direction of opening. The pawl has a recess which cooperates with upwardly extending catches and a forward deflector surface which cooperates with the catch of an adjacent plate in a stack of plates to prevent the pawl from dropping into operative position. At least one additional pawl is pivotally mounted on the drawing element and has an additional deflector surface rearwardly of the recess therein which cooperates with the catch of an adjacent plate. The recess in the pawl may be of a length to engage two catches carried by two adjacent plates.