Abstract: A cap for filter underdrain blocks is provided, wherein the cap has a porous body with a top surface, a bottom surface and downwardly extending flanges. The cap is installed on a filter block having a plurality of orifices in a top wall of the filter block for channelling fluids to and from an overlying filter media. The bottom surface of the cap along with the flanges define a distribution chamber above the orifices, and the cap has a porosity such that a fine grain filter media may be placed directly on the top surface of the cap without media penetrating therethrough and clogging the underdrain blocks. The distribution chamber enhances distribution of backwash fluids throughout the filter media, and the cap eliminates the need for a separate gravel support layer to be installed between the fine grain filter media and the underdrain blocks.

Abstract: A baffle system is described that significantly reduces media loss caused by turbulence encountered during gas and liquid backwashing of a discrete media filter bed. When positioned about a filter collection trough or outlet, the baffle system deflects rising gas bubbles away from the collection trough and disengages filter media from the backwash liquid.

Abstract: A filter for a machine tool operative to filter one of steel, brass, and copper from a liquid agent is disclosed herein. The filter consists of a cylindrical container having a closed top end and a closed bottom end, an upper duct positioned near the top end of the container, a lower duct positioned near the bottom end of the container and having a lower diffuser fluidly connected thereto, and a filtering element surrounding the lower diffuser. The filter element consists of ilmenite particles having a density (d) of about 6 g/cm.sup.3 and a size ranging between a smallest size of about 0.2 mm and a largest size of about 1.0 mm, the ilmenite particles being in the form of grains having sharp edges and irregular sized faces.

Abstract: An assembly for removing wash water for washing filters containing granular filter material, which are washed simultaneously with water and air, such as those employed especially in water treatment, and recovering the particles of granular filter material entrained by the water during the washing which includes a collecting member having calibrated holes for collecting and removing dirty water, internal and external partitions placed on each side of the collecting member, defining a water recovering zone inside the internal partitions and between the internal and external partitions, tranquil flow zones promoting the separation, by downward concurrent settling of the particles of granular material and of the dirty water to be removed, and a baffle intended to avoid disturbing the preceding zones by the water/air/granular material three-phase mixture formed during the washing, placed under said zones and directing the three phase mixture towards an external degassing zone where the air is removed before the re

Abstract: A method of washing an upflow filter between service runs employs a filter bed having a non-buoyant particulate filter layer through which influent to be filtered is directed in an upward direction, and through which liquid employed in the washing operation is directed in an upflow direction. A two-stage washing operation includes the steps of first directing a combination of air and liquid in an upflow direction through the filter layer with the velocity of the liquid being less than the minimum fluidization velocity of the filter layer, for disrupting only some floc retained in the filter layer during a previous service run, and thereafter directing only liquid in an upflow direction through the filter layer at a velocity less than the minimum fluidization velocity of the filter layer for removing disrupted floc from the filter layer while leaving some floc attached to said particulate media of the filter layer.

Abstract: An underdrain lateral for a liquid purification system is described. The lateral has three chambers, a primary chamber, a compensating chamber, and gas chamber. Turbulence is minimized during cleansing of the purification media by isolating the gas from the liquid and the backwash liquid. This is accomplished by feeding gas into the gas chamber so that the chamber is occupied by gas only during cleansing. Orifices in the wall between the primary and compensating chambers and in the baffle between the compensating and gas chambers provide compensation for even distribution of liquid in the lateral. The design also enables the use of cut outs in the gas chambers to equalize gas pressures and flow among the laterals and throughout the system bed and cut outs in the primary chambers to equalize liquid pressure and flow among the laterals and throughout the system bed.

Abstract: Apparatus for removal of a desired material from a liquid is described, in which the liquid is cycled through a plurality of liquid treatment containers in a first direction and brought into countercurrent contact with a medium for recovery of the desired material cycled through the treatment containers in a second, opposite direction. After treatment of the liquid, the medium is advantageously regenerated in a plurality of medium regeneration containers. The used medium is cycled through a plurality of medium regeneration containers in a first direction and brought into countercurrent contact with a medium regeneration liquid cycled through the regeneration containers in a second, opposite direction.

Abstract: A filtration apparatus includes a vertical column of filter media contained in and defined by a liquid-impervious vessel. A filtrate collection chamber is fixedly and centrally located in the media column. The collection chamber has liquid impervious top and sidewalls and an open bottom, whereby liquid to be filtered and introduced through a feed pipe at the top of the media column passes downward through the media column past the collection chamber and then upward into the collection chamber, is removed through a filtrate collection pipe. The apparatus may include equipment for continuously washing and recycling the filter media, and auxiliary alternatives for increasing the efficiency of the apparatus. Also included is the novel method for practicing the invention, particularly with the novel apparatus.

Abstract: Systems and methods for clarifying liquids, especially water, of the two stage upflow/downflow type that operate in a filtering mode, a first stage flush mode and a bistage backwash mode are improved by the use in the first, upflow stage of particulate filter media consisting of solid particles with a specific gravity of between 3.5 and 4.4 and a size between 1.5 and 4 mm. and, preferably, in the second, downflow stage particulate filter media consisting of solid particles having a specific gravity of between 1.5 and 4.0 and sizes of between 0.3 and 1.5 mm and providing for upward passage of gas bubbles through the first stage media particles without appreciable expansion thereof during at least part of each flush and backwash mode of operation.

Abstract: An underdrain lateral for a liquid purification system is described. The lateral has three chambers, a primary chamber, a compensating chamber, and gas chamber. Turbulence is minimized during cleansing of the purification media by isolating the gas from the liquid and the backwash liquid. This is accomplished by feeding gas into the gas chamber so that the chamber is occupied by gas only during cleansing. Orifices in the wall between the primary and compensating chambers and in the baffle between the compensating and gas chambers provide compensation for even distribution of liquid in the lateral. The design also enables the use of cut outs in the gas chambers to equalize gas pressures and flow among the laterals and throughout the system bed and cut outs in the primary chambers to equalize liquid pressure and flow among the laterals and throughout the system bed.

Abstract: Underdrain lateral system, which is especially adapted for use in a gravity filter bed, includes, as its preferred embodiment, scallop-shaped laterals having an upper, wrapped wire, slotted screen surface. The screen surface supports and retains the filter media particles directly, without the necessity of an underlying gravel layer, and is itself supported by channel-shaped rod members which are welded to the wires. The web portions of the channel rods perform the function of simultaneously distributing air and water during backwashing, and include small apertures in upper channels and larger apertures in lower channels to cause a plenum to be formed inside the laterals which ensures that the distribution of air and water will be uniform throughout the lateral, even if the lateral is not perfectly level.

Abstract: There is disclosed a granular filtration system having a separator trough with an air deflection baffle of improved shape and operation, preferably combined with an airlift mechanism for cleaning or removing settled granular media particles from the upper surface of the air deflection baffle. The air deflection baffle is used in a regeneration method for the granular media filtration system in which the granular media is purged of filtered solids by backflushing with air and water. In this application, the air-deflection baffle is installed beneath and adjacent to the open throat of a solids separation vessel, typically which is in the form of a trough spanning the width of the filtration vessel and having an inclined bottom wall with an open throat. The improved configuration of the air deflection baffle is generally an inverted W-shape. A plurality of open-ended tubes are secured on the air deflection baffle, transversely to the longitudinal axis thereof.

Abstract: Apparatus (1) for treating fluid, in this case wastewater, comprising a treatment vessel or tank (2), means (3) to supply wastewater to be treated in a pulsed sequence to the vessel, and means (4) to supply treatment fluid, in this case comprising oxygen to the vessel or tank (2) in a pulsed sequence opposite to the pulsed sequence of the supply of wastewater to be treated.

Abstract: A cap for filter underdrain blocks is provided, wherein the cap has a porous body with a top surface, a bottom surface and downwardly extending flanges. The cap is installed on a filter block having a plurality of orifices in a top wall of the filter block for channelling fluids to and from an overyling filter media. The bottom surface of the cap along with the flanges define a distribution chamber above the orifices, and the cap has a porosity such that a fine grain filter media may be placed directly on the top surface of the cap without media penetrating therethrough and clogging the underdrain blocks. The distribution chamber enhances distribution of backwash fluids throughout the filter media, and the cap eliminates the need for a separate gravel support layer to be installed between the fine grain filter media and the underdrain blocks.

Abstract: The filtration system provides a long horizontal flow path through buoyant filter media. The filter media is contained in a vessel and the relationship between the water level in the vessel and the amount of filter media is such that the media extends completely across the horizontal flow path of the water during the filtration mode of operation. The system is configured so that the buoyant media volume expands during a cleansing mode of operation.

Abstract: A filter block having a plurality of exterior and interior walls defining a plurality of interior chambers, said chambers including at least a first and second conduits parallel to the longitudinal axis of said block, one disposed above the other, with a third conduit provided to supply gas under pressure to the upper conduit; a top exterior wall of the block having a plurality of apertures distributed thereover. The interior chambers comprise separate conduits for both gas and liquid backwash flows. The interior walls defining the conduits are disposed to provide even distribution of the backwashing gas and to provide bearing support for the top wall of the block.

Abstract: An improved apparatus and method for operating a granular medium filter is disclosed. The apparatus comprises an improved underdrain structure made up of a plurality of rectangular compartments which allows the filter bed to be "air pulsed" as well as backwashed for thorough cleaning of the bed. Nozzles are positioned within the rectangular compartments and directed vertically into the filter bed. Fluid from the nozzles helps to break up the bed during backwashing as well as countereact size classification of the medium during this process. The method of operating a filter with the improved underdrain structure is also described.

Abstract: A flume distribution system includes a distributor having a stationary lower portion and a removable upper portion. The lower portion defines a duct which is in fluid communication with a flume and at least one underdrain lateral. The lower portion also includes an apertured end wall which abuts one of the underdrain laterals at a lateral inlet, and a stop is disposed within the duct and spaced from the end wall. The duct receives a removable orifice plate which is adapted to pivot between a slant inactive position abutting the stop and an upright active position restricting the aperture in the end wall. During backwash operations, water is introduced to the flume and enters each duct in the lower portion of the distributor, and the pressure of the incoming water causes the orifice plate to pivot from the slant position to the upright position, reducing the cross-sectional area of the aperture in the end wall and thereby regulating the velocity of backwash flow from the flume into the lateral inlet.

Abstract: A biological contactor with a granular bed including a layer based on activated carbon, the material of which satisfies the following conditions:density between 0.18 and 0.32 g/cm.sup.3,carbon tetrachloride adsorbing power between 60% and 120% by weight,carbon tetrachloride retention less than 25% by weight of the carbon tetrachloride adsorbed mass,the carbon tetrachloride adsorbed mass, methylene blue: between 5 and 30 ml,particle size: between 0.5 and 1.5 mm effective size with a coefficient of uniformity less than 2.A washing cycle (air only; air plus water; water only) of the contactor is triggered when a parameter representative of the population of algae in said layer reaches a predetermined set point threshold.

Abstract: A method of washing an upflow filter between service runs employs a filter bed having a non-buoyant particulate filter layer through which influent to be filtered is directed in an upward direction, and through which liquid employed in the washing operation is directed in an upflow direction. A two-stage washing operation includes the steps of first directing a combination of air and liquid in an upflow direction through the filter layer with the velocity of the liquid being less than the minimum fluidization velocity of the filter layer, for disrupting only some floc retained in the filter layer during a previous service run, and thereafter directing only liquid in an upflow direction through the filter layer at a velocity less than the minimum fluidization velocity of the filter layer for removing disrupted floc from the filter layer while leaving some floc attached to said particulate media of the filter layer.

Abstract: An underdrain lateral for a liquid purification system is described. The lateral has three chambers, a primary chamber, a compensating chamber, and gas chamber. Turbulence is minimized during cleansing of the purification media by isolating the gas from the liquid and the backwash liquid. This is accomplished by feeding gas into the gas chamber so that the chamber is occupied by gas only during cleansing. Orifices in the wall between the primary and compensating chambers and in the baffle between the compensating and gas chambers provide compensation for even distribution of liquid in the lateral. The design also enables the use of cut out in the gas chambers to equalize gas pressures and flow among the laterals and throughout the system bed and cut outs in the primary chambers to equalize liquid pressure and flow along the laterals and throughout the system bed.

Abstract: A filter underdrain apparatus comprises plate means forming a plurality of horizontal distributor conduits, the conduits being in juxtaposed, laterally-spaced relationship and constructed and arranged to defined alternating conduits and troughs of a filter underdrain. At least some of the horizontal distributor conduits include interior partitions extending along such conduits and dividing the interior of each such conduit into a liquid passage and a gas passage. Liquid metering orifices communicate the interior of the liquid passage with the exterior of the distributor conduit for substantially evenly distributing backwash liquid flows from the liquid passage and for passing filtered liquid flows into the liquid passage. Gas metering orifices communicate the interior of the gas passage with the exterior of the distributor conduit for substantially evenly distributing gas from the gas passage when connected with a pressurized gas source.

Abstract: A filter system for achieving continuous filtering by the provision of three filter chambers disposed about a common vertical axis, each containing a filter bed comprised of buoyant particles through which the fluid to be filtered is passed in an upward direction and wherein provision is made for rehabbing the beds of particulate material as they become filled with solids, preferably in succession to enable continuous operation.

Abstract: The invention contemplates a water-treatment system wherein inlet water is subjected to continuous circulation, or at least to a plurality of cycles of circulation, in a loop wherein air under pressure is injected into the water prior to passage through a magnetic-energy treatment device. The recirculation involves a tank which thus provides a volume of available pretreated water, against which to drawn in accordance with intermittent demand. Magnetic-field treatment of the aerated water creates particulates, from oxidizable impurities such as iron, and these particulates are separable by filtration; and as to those impurities as involve dissolved gases, such as radon or hydrogen sulfide, the gases are driven from solution and vented (along with excess air) external to the treated-water outlet of the system.

Abstract: A liquid filtration system is provided which includes a traveling bridge carriage mounting air scour and backwash means within a single hood structure for successively cleaning each of a plurality of roughing filter cells and polishing filter cells formed in a filtration tank. The air scour means includes an air scour inlet conduit for supplying air under pressure to each cell. The backwash means includes a backwash conduit for creating suction within each filter cell. The single hood structure is adapted to sealingly engage each of the roughing and polishing filter cells. For the roughing filter cells, only an air scour operation is carried out while, for the polishing filters, backwash is done.

Abstract: A single chamber filter module containing a buoyant bed of filter particles through which the fluid to be filtered is passed in an upward direction through the bed so that the solids become trapped within the bed. The filtrate is withdrawn from the upper end of the module. Periodically, the filter bed is rehabbed by dispersing the bed, washing the entrapped solids from the particles and discharging the solids from the lower end of the module.

Abstract: An accumulating tank serving as a filter for an overflowing swimming pool, and more particularly a device for filtering water from an overflowing swimming pool using an accumulating tank acting as a gravity filter. The accumulating tank (1) serves as a prefilter, and a filter for water from the pool; it filters by decantation through a filtering mass (8, 9). It comprises apparatus for cleaning the filtering mass (8, 9) by reversing the direction of water current (F2), so as to cause to overflow the volume of water from the accumulating tank (1) and recover the impurities by overflow of the used water into a gutter (15) and evacuation for emptying by a pipe (24).

Abstract: A liquid filtration system is provided which includes a traveling bridge device mounting air scour and backwash means for successively cleaning each of a plurality of filter cells formed in a filtration tank. The air scour means includes a first hood open to atmosphere and adapted for sealing engagement with each filter cell. The first hood may include an air scour inlet conduit for supplying air under pressure to each cell. The backwash means includes a second hood also adapted for sealing engagement with each filter cell and includes a backwash conduit for creating suction within each filter cell. In one embodiment where the air scour pump is mounted on the traveling bridge carriage, each cell is provided with a vertical riser adapted for sealing engagement with the air scour inlet conduit in the air scour hood. In an alternative arrangement, the air is supplied from a ground installed pump, through a common inlet manifold, to the individual cells.

Abstract: A method and apparatus for a regenerating dynamic adsorber system which removes a contaminant from fluid. The system includes at least one adsorption bed having a contaminant removal capacity that is based substantially on the flow of the contaminated fluid through the bed. The system alternately cleanses the contaminated fluid by feeding the contaminated fluid from a first volume to the bed and issuing cleansed fluid to a second volume, and regenerates the bed by providing clean fluid from a third volume and issuing the fluid back to the third volume.

Abstract: An oxidative evaporation process for treating waste water or other aqueous solutions containing organics or reduced forms of inorganics is described. The process relies upon excessive amounts of pressurized oxygen gas to both oxidize the solution and to increase the solution's evaporation rate. The oxidized liquid effluent from a reactor undergoes a series of flashing steps until a saturated solution is produced which readily crystallizes upon cooling.

Abstract: A filtration system and method for the removal of suspended solids from a contaminated liquid in which the contaminated liquid is pumped into the top of a vessel and allowed to flow through a bed of polyethylene particles which acts as a filtering medium. Periodically the flow of liquid through the polyethylene filter bed is stopped and a backwash cycle in which the contaminated liquid is pumped in a reverse flow direction through the filter bed is initiated. By thoroughly agitating the filter bed and polyethylene particles, contaminants are loosened and removed from the polyethylene particles and placed back into the liquid. The highly concentrated contaminated liquid is removed from the vessel for further processing. The filter bed is reset and the filtering cycle is again initiated.

Abstract: A device for the collection of water from a granular material bed filter includes means for injecting water and air through the filtration bed as well as an outer chute provided with a weir for the discharge of water, characterized in that it is made of a storage capacity placed between the filter and the discharge chute and defined by a vertical perforated wall such as a grid situated in vertical alignment with the filter vertical wall, and a plane slanting inwardly to the inside of the filter, said slanting plane connecting the weir for the discharge of the water via the chute to the filter wall situated below the vertical perforated wall such as the grid.

Abstract: Liquid which has been partially clarified in the settling zone of a clarifier tank is channelled through a filtration compartment containing a buoyant particulate filtration media. The media particles are periodically agitated so that trapped solids are separated from the media and retained in the clarifier tank.

Abstract: A suspension is filtered by a granular filtrating layer while flowing through the granular filtrating mass as a vertical ascending current. The granular mass is, for the purpose of being washed with air, driven continuously by a compressed air ejector into a tube where it follows an ascending motion and at the outlet of which it is washed with water above the layer where the filtration is carried out. Thereafter, the washed mass is recycled by gravity onto the upper portion of the filtration layer. The charged granular mass which has been subjected to the first or air washing operation is fluidized above the filtration layer and subjected to an extra washing operation with water and pressurized air.

Abstract: An air/water distributor underdrain assembly for providing a uniform distribution and metering of backwash air and/or water through a filter bed. The distributor assembly includes a distributor member which defines a distributor chamber for receipt of backwash air and/or water thereinto. A plurality of first and second spaced apart openings extend through the distributor member. A shroud extends downwardly into the distributor chamber from each of the first openings in fluid communication with an intermediate portion of the distributor chamber for directing backwash water therethrough. Backwash air collected in a gas compartment formed in an upper portion of the distributor chamber is directed through the second openings.

Abstract: A device for removing hydrogen sulfide from well water having in situ activated carbon adsorbent regeneration. The device includes a tank with a water inlet, a water outlet and a steam outlet. The hydrogen sulfide adsorbent material is situated in the tank so that water entering through the water inlet must pass through the adsorbent material before exiting the water outlet. The tank also has a heating element which may be activated to boil water which is in communication with the adsorbent material. The water inlet, the water outlet, and steam outlet each have valves which are operated so that water may enter the tank and pass through the hydrogen sulfide adsorbent material and out the water outlet during water purification stage without any water going out the steam outlet.

Abstract: A method and apparatus for backflushing downflow filters is disclosed which comprises providing a closed container having contiguous, vertically adjacent filter layers. A layer of gravel is provided below the filter layers and is separated from the bottom filter layer by a foraminous gravel retention member. Fluid under pressure is introduced through a plurality of fluid nozzles into the gravel layer to backflush the filter layers. Backflush fluid in introduced at a sufficient flow rate to fluidize all of the filter layers to segregate them in accordance with their specific densities and particle size. Introducing the backflush fluid into a gravel layer through a plurality of nozzles helps prevent development of localized areas of high fluid velocity that can cause intermingling of the filter layers during backflush.

Abstract: An apparatus for universal water treatment with cylindrical housing and rotating ring-baskets, in which the housing is provided with untreated water inlet and purified water outlet stubs and the rotating filter baskets contains a back-washing chamber for regeneration of the baskets. The rotary filter baskets contain also an annular coagulating space formed in the cylindrical housing connected to the untreated water inlet stub. The rotating filter baskets are arranged uniaxially with the coagulation space and with each other. The filter baskets may be arranged within or above each other. Several filter beds are arranged in the filter baskets separated from each other and provided with independent back-washing chamber. The filter beds are arranged between cylindrical, perforated partition walls.

Abstract: There is provided an improvement in a waste effluent filter of the type including a tank, a generally flat fine mesh screen over the lower portion of the tank to define an underdrain cavity below the screen and a filter bed of particulate material having an upper surface and a lower general surface adjacent the underdrain cavity. The particle size of the particulate material being greater than the size of the apertures in the fine mesh screen. The filter improvement includes a jet creating grid for creating a plurality of upwardly directed hydraulic jets evenly distributed throughout the filter bed during the filtering of the effluent through the bed wherein the jet creating grid includes a plurality of nozzles in the bed itself substantially below the upper surface of the bed and above the fine mesh screen a selected distance to retain the lower layer of the bed undisturbed.

Abstract: A filter employing a discrete particle filter medium (3,11), such as graded sand or the like, in which the outlet passage (6) located at the bottom (1, 29,8) of a bed of filter medium is provided in which air can be employed in the backwashing process to agitate the filter medium. The filter has shallow coarser layers (9,10,28) of particulate material beneath the filter medium (11) itself and one set of outlet nozzles (14,19,27) having appropriately dimensional perforations positioned in the coarser or coarsest particle layer (9,28). In addition further finer perforated surfaces (16,23,30) communicate with the bottom of the filter medium (11) itself and the arrangement is such that when air is introduced perparatory to, or during backwashing the air emerges predominantly from the elevated finer perforated surfaces (16,23,30).

Abstract: A water filtration system is provided by an upflow filter vessel containing a buoyant filter media in series with a downstream downflow filter vessel containing a nonbuoyant filter media. The buoyant media filter vessel and nonbuoyant media filter vessel comprise two compartments of a common tank, separated by a central wall. Water from the upflow filter vessel passes over the top of this wall, or through one or more openings in this wall, to the downflow filter vessel. A common waste trough extends from one end of the tank to the other. Weir plates are fastened to the upper edges of this trough such that the trough steps upwardly in elevation at the central wall. Waste materials from the upflow filter vessel pass over the lower of these weir plates and into the waste trough during cleaning of the buoyant media filter. In contrast, waste materials from the nonbuoyant media filter flow over the upper weir plates and into the trough during cleaning of this latter filter.

Abstract: A submerged filter includes filtering matter in the form of a granular material contained in a vat having a floor for supporting the granular material. The liquid to be treated flows from the bottom to top and is brought into contact with a gas serving for the treatment of the liquid and circulating in the same direction. The filtering material is washed with water and air. The liquid to be treated, the treating gas, and the wash fluids are introduced into the filtering mass through the floor by means of nozzles which extend through the floor. Some of the nozzles essentially serve for introducing the treating gas, while others serve for introducing the liquid to be treated and the fluids for washing the filtering material.

Abstract: High rate filtration system includes an upflow filter vessel containing a bed of buoyant media followed by a downflow filter vessel containing a bed of nonbuoyant media. The upflow filter vessel is unobstructed by cross-sectional, media-confining screens. A horizontal trough structure collects filter effluent and makes it possible to clean the bed by diffusing air into the liquid below the bed so that average fluid density in the bed is reduced. The reduction in fluid density results in expansion of the bed as media particles descend by gravity.

Abstract: A filtration apparatus comprising a filter tank, a support provided at least at a lower interior portion of the filter tank, a filter medium layer composed of fiber lumps accumulated on the support, a filter medium spreading zone provided within the filter tank above the support, air injecting means disposed under the filter medium layer, prefilt inlet means disposed at an upper portion of the tank, and filtrate outlet means disposed at a lower portion of the tank. The apparatus is simple in construction and easy to operate, assures depth-type filtration with high accuracy and is easy to wash for the reuse of the filter medium.

Abstract: A liquid is filtered through a bed 7 of granular material and cleaning of the bed is conducted, when necessary, by upflow of wash water through orifices 9 and air through orifices 12 positioned mid-way between the orifices 9. An overflow 13 defines a free water space 15 above the bed and a baffle formed of elements 18, 19 and 20 surrounds the overflow outlet. During cleaning the wash water and air flow upwardly at rates such that some granular material is entrained by upflowing air bubbles and could be carried to the overflow 13 but substantially all the entrained granular material is separated from the entraining air bubbles at or near the top of the free space 15.

Abstract: This invention relates to a backwash outlet assembly for a liquid particulate filter. The outlet is adapted to retain particles which comprise the filter medium while allowing backwash liquid together with impurities to discharge to waste. The outlet comprises an outlet weir, and a substantially non-turbulent flow zone located upstream of the weir. A particle return passage extends from the floor of the zone to the filter bed and means are included to at least restrict back flow in the passage. Filter media particles carried in suspension in the backwash liquid fall under the action of gravity to the floor of the zone and by the velocity of the backwash liquid into the entrance to the return passage. Preferably the particle return passage extends from the zone adjacent the weir and filter media particles trapped in the return passage are automatically conveyed back to the filter.

Abstract: A water purification device comprises a raw water channel forming plate extending spirally along the inner wall of a filter tank. A collector for collecting filtered water, positioned in the layer of the filter medium substantially at the center of the raw water channel forming plate, is also disclosed. Since the raw water is filtered from the periphery of the layer of the filter medium and the continuous raw water channel formed by the spirally extending raw water channel forming plate enables the number of influx points of raw water into the raw water channel to be reduced to one at a minimum, the structure is simplified and manufacture costs are reduced.

Abstract: An activated carbon adsorption column for the treatment of waste water is continuously sterilized and/or regenerated in pulsed batches of carbon amounting to 5 to 25 percent of the working column quantity transferred, alternately, from the influent face of the column to one of two, off-stream blow case vessels for steam processing and returned to the effluent face of the working column upon the next programmed pulsing interim.

Abstract: The recovery of water-free desorbates from adsorption filters hampered not only by desorption with water vapor but also by water which is adsorbed at the adsorption media from the gas or the air to be purified and which water is likewise driven out during the desorption. It has now been found that desorbate without water can be recovered if the gaseous desorption medium is pre-dried in a water sorption filter with an adsorption medium having water-selective action, before entering the condenser-cooler. Bypasses avoiding the sorption water reservoir as well as the condenser-cooler also permit operating conditions which go beyond the normal desorption, namely, desorption with increased temperature for driving out less volatile residual loads as well as reactivating desorption. In a particular embodiment, the sorption heat accumulator can be combined with the condenser-cooler, an embodiment which can be employed particularly for recovery equipments.

Abstract: In a water purification apparatus in which a granular filter medium is washed by agitation imparted to the filter medium, a pipe adapted for collection of purified water is mounted within the heap of precipitated granular filter medium and enclosed by a filter mesh to prevent outflow of the filter medium. Sliding contact elements such as turns of a wire wound about the collecting pipe or linear brush-like members inserted on the collecting pipe are also provided between the pipe and the filter mesh so that both the inner and outer surfaces of the filter mesh may be cleaned during countercurrent washing of the filter medium for assuring optimum water permeation at all times.