Abstract: An underwater filtration system or operator which can be floated on and suspended in a river, lake, pond or other water body to filter water from the water body. The underwater filtration operator may be electrically charged with simultaneous introduction of continuous forced air to remove impurities from the water body and increase filtering efficiency and the system includes a split housing having a selected configuration and divided into one or more filtration units, each of which includes a filter medium or mediums for filtering water from the water body. A pump is provided in the interior of the system housing for receiving the filtered water from the filtration units and pumping the filtered water to a collection tank or dispenser, directly to an end user or to a reverse-osmosis water filtration unit for further filtration.

Abstract: An apparatus for filtering water and/or wastewater including at least one underdrain lateral. The underdrain lateral is configured to receive a liquid during a filtration cycle and directs a washing fluid through a filter bed of one or more layers of filter media during a washing cycle. The filter can take any form including but not limited to an upflow clarifier, an upflow filter, a downflow clarifier, a downflow filter and a bi-flow filter. The filter media may be supported by one or more layers of gravel. Alternatively, a porous plate can be attached to the underdrain lateral in place of the gravel layers. The washing cycle can be a liquid only wash, a gas only wash, a combined liquid and gas wash or a combination of any of the aforementioned wash cycles.

Abstract: A two-stage oxygenation system for use with a fluidized bed reactor is provided. The oxygenation system includes an oxygenation vessel coupled to receive oxygen from a source of oxygen, and a separator vessel coupled to receive feed from a source of feed. The separator vessel is coupled to receive recovered oxygen from the oxygenation vessel and recycle from the fluidized bed reactor. The oxygenation vessel is coupled to receive feed and recycle from the separator and to discharge oxygenated feed and recycle for delivery to the fluidized bed reactor and the recovered oxygen for delivery to the separator vessel.

Abstract: A fluid treatment system that includes at least one treatment module (“pod”) with rigid and impermeable inner and outer surfaces, and an annular center passage which is designed to provide an alternative flow path during the pod backwashing process. At least one chemical treatment media disposed in the interior portion of the pod. A riser extends upwardly through the pod so that the outer surface of the riser and the inner surface of the pod define the annular passage. At least one valve assembly controls the movement of a fluid within the annular passage. The pod is serviced by directing the fluid into the riser and then directing the fluid through the pod, a portion of the fluid flowing through the annular passage.

Abstract: A membrane filtration assembly (10) including a membrane module (5) having one or more permeable hollow membranes (6) supported therein by at least one header (7). A filtrate collection chamber (18) is associated with the header (7) and in fluid communication with lumens of the membranes (6) for collecting filtrate withdrawn through said membrane lumens. A filtration chamber (11) is provided for receiving feed liquid to be applied to the surface of membranes (6) within the module (5). The filtration chamber (11) encloses module (5) and extends beyond the height of the module (5).

Abstract: An embedded geometrically variable filter underdrain header and a method for constructing such a filter. Often the variation is a decrease in cross section along the header from the backwash media source, which avoids a pressure loss as liquid is diverted to the laterals along the header. The header is formed inside a filter underdrain basin and is embedded in the basin. The method for constructing the basin and header includes providing a mold for the basin and the header and filling the molds with concrete by pouring concrete into the area between the interior of the mold for the basin and the exterior of the mold for the header. After the concrete cures, the mold for the basin may or may not be removed, while the mold for the header is kept in place.

Abstract: A high rate, upflow filtration system is described in which a compressible, fibrous lump filtration media is compressed to adjust the porosity and collector size of the media in the bed and to provide a porosity gradient within the bed proceeding from more porous to less porous in a direction opposite to the flow of fluid so that filtration proceeds in a direction from a more porous to a less porous filter bed. Larger particles are removed by the more porous media and successively smaller particles are removed as the filter bed becomes less porous. The system is capable of reducing the turbidity of influent municipal wastewater from about 8 NTU to about 2 NTU at a wastewater flow rate of from about 820 to 1230 L/m2·min (20 to 30 gal/ft2·min), at a bed compression ration of from about 15 to 40 percent, and at a backwash rate of from about 1 to 6 percent based on the total wastewater passing through the filter.

Abstract: A water softening system and process for softening water on an as needed basis is disclosed. The system and process softens water without the addition of a substitute metal exchange cation.

Abstract: A fluid distribution system for directing fluids through a filter system. The fluid distribution system ensures proper distribution of fluids during the process of filtering as well as the process of washing a filter bed. The fluid distribution system may be used with numerous filter systems including but not limited to an upflow filter, a downflow filter, a combined upflow/downflow filter and/or multiple downflow filters connected in series.

Abstract: A filtration system that includes a plurality of underdrain blocks arranged to define a plurality of laterals. Each underdrain block defines an interior and an exterior and has an orifice that provides fluid communication between the exterior and the interior. The system also includes a plurality of media retaining plates. Each plate includes a plurality of slots that extend through the plate. Each slot has an average width of less than 0.065 inches. Each plate connects to only one of the plurality of underdrain blocks such that the slots provide fluid communication between the exterior and the orifice of the underdrain block to which the plate is attached.

Abstract: A filter underdrain system and a method for measuring the water flow through the underdrain filter system. The apparatus includes panel members assembled to form a perforate grid on the filter base structure of an underdrain block. The panels are generally rectangular and have an upper and lower surface. Multiple apertures are provided in the panel member. The number and/or size of the apertures are dimensioned to prevent the egress of filter media and to obtain substantially uniform backwash flow in the underdrain thereby reducing or eliminating water maldistribution.

Abstract: The invention is directed to a filter underdrain for supporting a filter media between at least two dividers forming at least one cell, which includes at least one porous plate for supporting the filter media for filtering a fluid, the porous plate spanning across at least one of the dividers; and a plurality of support members beneath the porous plate, the support members containing at least one port for draining the fluid after the fluid passes through the porous plate. The porous plates may be bound together by a lap joint and an end section may be included between at least two of the support members, the end section containing at least one pocket for holding the porous plate.

Abstract: The invention recites a filtration tank including a chamber for holding liquid to be filtered, the filtration tank includes a fluid inlet for providing liquid to the chamber. The filtration tank further includes a fluid outlet and at least one filter block disposed between the inlet and the outlet, wherein the at least one filter block includes a porous cap having an average pore size of up to about 250 microns.

Abstract: The invention recites a filtration system including a block including a first wall and a second wall substantially parallel to the first wall. A top surface that is substantially perpendicular to the first wall is disposed between, and coupled to, the first and second walls to at least partially define an inner chamber. The top surface further includes an orifice defining a passageway between a block exterior and the inner chamber. A plate including a plurality of slots, each slot having a width of less than about 0.065 inches, and a slot outlet, is coupled to the top surface of the block. The slot outlets in the plate are substantially coplanar and the plate, when coupled to the block, substantially covers the orifice.

Abstract: A fluid distribution system for directing fluids through a filter system. The fluid distribution system ensures proper distribution of fluids during the process of filtering as well as the process of washing a filter bed. The fluid distribution system may be used with numerous filter systems including but not limited to an upflow filter, a downflow filter, a combined upflow/downflow filter and/or multiple downflow filters connected in series.

Abstract: A modular filter system and a method of repairing and/or replacing one or more components thereof. The modular filter system includes a traveling backwash hood assembly and a plurality of filter cells having media contained therein. The traveling backwash hood assembly includes a hood and a baffle assembly. Preferably, the hood has at least one opening formed therein and a cover plate operably associated with the at least one opening. The baffle assembly includes a plurality of baffles for directing the flow of fluid. The baffle assembly is detachably connected to the hood to permit the baffle assembly to be moved relative to the hood to permit an individual to readily gain access to the baffle assembly to repair or replace one or more components thereof.

Abstract: The invention is directed to an automatic backwash filter system that includes at least one influent port for introducing a fluid to the filter; a plurality of partitions forming a plurality of compartments for holding a filtering media for filtering the fluid; at least one porous plate for supporting the plurality of partitions; wherein each of the partitions is mounted atop a continuous portion of the porous plate; and at least one effluent port for draining the fluid away from the compartments. The filter may also include a filter media comprising one or more selected from the group consisting of sand, anthracite coal, and activated carbon.

Abstract: The present invention relates to the raw water-filtering technical field, and is to provide a high speed filtering apparatus which can filter a great amount of raw water containing suspended substances (SS) at a high concentration at a high speed. Floating filter media 2, which are composed of a foamed polymer having an apparent density of 0.1 to 0.4 g/cm3 and a 50% compression hardness of not less than 0.1 MPa and have uneven shapes or cylindrical shapes with sizes of 4 to 10 mm, are charged into an up-flow type filtering tower 1. The raw water containing SS at a high concentration is filtered by passing it through the filtering tower 1 at a linear water-passing speed of 100 to 1000 m/day. While the floating filter media 2 are not compacted, a high SS-capturing percentage can be obtained. Back washing can be also effected at a high linear washing speed of 1.2 to 4.0 m/min.

Abstract: The invention recites a filter comprising a block including an outer wall defining an inner chamber and a block exterior, and a conduit having a conduit wall, a first conduit end, a second conduit end, and an inner flow path providing fluid communication between the first and second conduit ends. The conduit wall includes an orifice therethrough. The conduit is coupled to the block such that the first conduit end is in fluid communication with the inner chamber of the block and the second conduit end and the orifice are in fluid communication with the block exterior.

Abstract: The present invention provides an apparatus and method for filtering fluids with a compressible filter media within at least a portion of a housing inwardly compressible.

Abstract: A filter underdrain apparatus and a method for manufacturing such apparatus. The apparatus includes a cover member, a water orifice member and a bottom member, each being individual pieces. The cover is placed over the water orifice member and connected thereto by welding. The bottom member is likewise connected to the cover and water orifice members by welding. A water passageway and an air passageway are defined in the inside of the assembled members. Water egress from the water passageway is provided by holes in the water orifice member and the cover. Air egress from the air passageway is provided by holes in the cover.

Abstract: A liquid filtering apparatus is placed in a vessel having a bed of filtration material and an intake for introducing unfiltered liquid, that includes a washbox, an airlifting tube extending from the washbox and including an intake end and means for introducing a primary gas to the airlifting tube, the airlifting tube passing through a central pipe, which extends from just below the washbox to a position just above the intake end. At least one screen cartridge is oriented in a generally angular downward direction in the bed and is in communication with an effluent chamber defined in part by the outer surface of the central pipe. A reject line extends from the washbox, and an effluent collector extends from the effluent chamber. A method of filtering and cleaning the filtration material is also disclosed.

Abstract: An underwater filtration operator which can be suspended in a river, lake, pond or other water body to filter water from the water body. The underwater filtration operator may be electrically charged to discharge impurities in the water body and increase filtering efficiency and the operator includes a housing having a selected configuration and divided into one or more filtration units, each of which includes a filter medium for filtering water from the water body. A pump is provided in the housing for receiving the filtered water from the filtration units and pumping the filtered water to a collection tank or dispenser or directly to an end user or to a reverse-osmosis water filtration unit for further filtration.

Abstract: A filtration apparatus includes a tank having an upper chamber and a lower baffle, layers of stone and carbon between the upper chamber and the lower baffle, a water inlet to the upper chamber, and a water outlet below the lower baffle. The upper chamber is divided by a vertical baffle which separates the water inlet from a backwash outlet. A backwash inlet is provided below the lower baffle. An air manifold coupled to an air pump is placed between the lower baffle and the upper chamber. During backwash, air is mixed with water to cause a turbulent flow. The baffle in the upper chamber prevents filter media from exiting the apparatus during backwash.

Abstract: A high rate, upflow filtration system is described in which a compressible, fibrous lump filtration media is compressed to adjust the porosity and collector size of the media in the bed and to provide a porosity gradient within the bed proceeding from more porous to less porous in a direction opposite to the flow of fluid so that filtration proceeds in a direction from a more porous to a less porous filter bed. Larger particles are removed by the more porous media and successively smaller particles are removed as the filter bed becomes less porous. The system is capable of reducing the turbidity of influent municipal wastewater from about 8 NTU to about 2 NTU at a wastewater flow rate of from about 820 to 1230 L/m2·min (20 to 30 gal/ft2·min), at a bed compression ration of from about 15 to 40 percent, and at a backwash rate of from about 1 to 6 percent based on the total wastewater passing through the filter.

Abstract: An improved underdrain block for an underdrain system supporting a filter media bed in a liquid filtration system is provided. The underdrain blocks are preferably made of an extrudable polymeric material that is extruded in relatively long sections to provide light weight, strong, easily manufactured underdrain systems having a lower profile than prior art underdrain blocks. The underdrain block comprises an upper wall, side walls, a lower wall, at least one lateral member between the upper wall and the lower wall, at least two chambers within the underdrain block, each chamber being defined by the lateral member, a plurality of upper orifices in the upper wall of the underdrain block, and a plurality of internal orifices in the lateral member. The underdrain block is substantially greater in longitudinal length than a longitudinal distance between the upper orifices.

Abstract: A liquid filtering apparatus is placed in a vessel having a bed of filtration material and an intake for introducing unfiltered liquid, that includes a washbox, an airlifting tube extending from the washbox and including an intake end and means for introducing a primary gas to the airlifting tube, the airlifting tube passing through a central pipe, which extends from just below the washbox to a position just above the intake end. At least one screen cartridge is oriented in a generally angular downward direction in the bed and is in communication with an effluent chamber defined in part by the outer surface of the central pipe. A reject line extends from the washbox, and an effluent collector extends from the effluent chamber. A method of filtering and cleaning the filtration material is also disclosed.

Abstract: A fluid distribution system for directing fluids through a filter system. The fluid distribution system ensures proper distribution of fluids during the process of filtering as well as the process of washing a filter bed. The fluid distribution system may be used with numerous filter systems including but not limited to an upflow filter, a downflow filter, a combined upflow/downflow filter and/or multiple downflow filters connected in series.

Abstract: A fluid distribution system for directing fluids through a filter system. The fluid distribution system ensures proper distribution of fluids during the process of filtering as well as the process of washing a filter bed. The fluid distribution system may be used with numerous filter systems including but not limited to an upflow filter, a downflow filter, a combined upflow/downflow filter and/or multiple downflow filters connected in series.

Abstract: An improved vertical filtration unit which includes an airlift and a washbox designed for more efficient washing of dirt particles from the filtration material. The washbox consists of a filter media shield, and a washbox skirt for washing of the filtration material. A throttling valve on the wash water discharge line regulates the overall cleaning rate of the unit. The filtered liquid is discharged via a riser pipe which feeds into a filtered liquid box before exiting the filtration unit.

Abstract: The present invention provides a floating media biofilter having an economical structure which allows energy efficient and water conserving backwashing of the floating media. The biofilter includes a filter chamber fluidly connected to a charge chamber which is adapted for accumulating air. A trigger device positioned between the charge chamber and filter chamber selectively allows the flow of air from said charge chamber to said filter chamber. An air source is connected to the charge chamber and slowly supplies air thereto. The backwash cycle is initiated by the trigger device allowing air to escape from the charge chamber into the filter chamber and agitate the floating media. Simultaneously, water from the filter chamber flows into the charge chamber. After the trigger device closes, air again accumulates in charge chamber in preparation for another backwash cycle.

Abstract: A filter apparatus removes foreign substances contained in raw water by passing the raw water through a filter layer (8) made up of a particulate filter medium disposed in a filter tank (1).

Abstract: An apparatus for recovering a specific ingredient in sea water, which comprises an adsorbing bed tank, a layer of an adsorbent charged on the bottom portion of the adsorbing bed tank, a sea water intake pipe provided in a bottom portion of the adsorbing bed tank, a sea water intake opening for taking in sea water and leading the sea water taken in to the sea water intake pipe, a communicating pipe communicating with an end of the sea water intake pipe, a precipitating section through which the communicating pipe communicates with the sea water intake opening, and an evacuator for discharging sea water inside the adsorbing bed tank, sea water inflow openings being provided between said sea water intake pipe and the tank and being provided with check valves, said check valve being adapted to only upwardly flow sea water into the adsorbent layer inside the adsorbing bed tank through the sea water inflow openings, wherein a sectional area of the precipitating section as taken perpendicularly to a flowing directio

Abstract: A biological oxidation filter system can be used as a pretreatment process in water treatment, or for processing sewage or wastewater by reproducing the purification mechanisms in nature environments. It has a physical screening function and an oxidation function through the aeration and biological decomposition. The biological oxidation filter system includes: a raw water inflow unit; a biological contact filter unit; a filtrate outflow unit; an oxidation air supply unit supplying air and/or oxygen in order to provide a proper growth environment for microbial flora and perform the oxidation in the biological contact filter unit; and an air backwashing unit and a water back washing unit for backwashing the filter media when the biological contact filter unit is blocked.

Abstract: A filter cartridge end-of-life mechanism and a filter cartridge assembly for a water treatment device. The end-of-life mechanism comprises a float which is moved along an escapement path each time the device is filled. A counting mechanism connected to the float provides a continuous visual indication of the amount of useful life remaining in the filter cartridge. The cartridge assembly includes a tray detachably connected to a filter cartridge. The tray is positioned beneath the outlet end of the cartridge to remove water treatment particles from the treated water.

Abstract: An apparatus for continuously filtering a suspension includes a filter-medium washer provided with length-adjustable walls.

Abstract: A filter comprises a main tank and at least two separate beds of particulate filter media contained in respective conical recipients integrated within the main tank so as to minimize the overall height and weight of the filter. A transport pipe is provided for each conical recipient in order to transport dirty filter media therefrom to a washing device in which the dirty filter media is washed as it flows downwardly in counter-current with a wash liquid. A filter media return pipe is provided for each conical recipient in order to return the cleaned filter media therein. The provision of multiple transport pipes and return pipes ensures efficient distribution of the filter media within the filter.

Abstract: To adsorb, on solid adsorbent particles, constituents dissolved in liquid, or to desorb (extract), from solid desorbent particles, soluble constituents in liquid, in a container a packed bed formed from granular material is mixed with adsorbent particles or desorbent particles smaller than 200 &mgr;m, said bed moves downwards by virtue of gravity, said liquid is passed upwards through the bed by means of a pressure differential, the said dissolved constituents being adsorbed on the solid adsorbent particles or the said soluble constituents being extracted from the desorbent particles.

Abstract: An improved underdrain block for an underdrain system supporting a filter media bed in a liquid filtration system is provided. The underdrain blocks are preferably made of an extrudable polymeric material that is extruded in relatively long sections to provide light weight, strong, easily manufactured underdrain systems having a lower profile than prior art underdrain blocks. The underdrain block comprises an upper wall, side walls, a lower wall, at least one lateral member between the upper wall and the lower wall, at least two chambers within the underdrain block, each chamber being defined by the lateral member, a plurality of upper orifices in the upper wall of the underdrain block, and a plurality of internal orifices in the lateral member. The underdrain block is substantially greater in longitudinal length than a longitudinal distance between the upper orifices.

Abstract: A concurrent backwash distribution apparatus for a filter having a filter tank and a plurality of underdrain laterals includes a baffle positioned in a common main conduit to define an auxiliary flume between the baffle and the underdrain laterals. The auxiliary flume is in fluid communication with the common main conduit and the underdrain laterals. The baffle has at least one flume liquid metering orifice preferably located near the bottom of the baffle so that it may be below a gas/liquid interface in the auxiliary flume during concurrent gas/liquid backwash operations. A flow distribution plate may be positioned between the auxiliary flume and the underdrain laterals, the flow distribution plate having at least one liquid metering orifice and at least one gas metering orifice. The baffle may take one of many forms. The baffle creates an adequate liquid pool in the common main conduit for low velocity flow of backwash liquid while at the same time providing uninhibited flow of backwash gas.

Abstract: A filter media support system that reduces media clogging and head loss in granular filtration systems by providing a layered porous plate. The porous plate can have multiple layers of fine sized and coarse sized pores. The porous plate is positioned between the media and the filter bottom. The filter media support system is securely anchored to the infrastructure of the underdrain system thereby inhibiting media penetration of the filter bottom and avoiding seal failures. The infrastructure can be air lateral piping fitted beneath the underdrain blocks of the support system. The anchors can be secured to pipe clamps circumscribing the air laterals.

Abstract: A concurrent backwash distribution apparatus for a filter having a filter tank and a plurality of underdrain laterals includes a baffle positioned in a common main conduit to define an auxiliary flume between the baffle and the underdrain laterals. The auxiliary flume is in fluid communication with the common main conduit and the underdrain laterals. The baffle has at least one flume liquid metering orifice preferably located near the bottom of the baffle so that it may be below a gas/liquid interface in the auxiliary flume during concurrent gas/liquid backwash operations. A flow distribution plate may be positioned between the auxiliary flume and the underdrain laterals, the flow distribution plate having at least one liquid metering orifice and at least one gas metering orifice. The baffle may take one of many forms. The baffle creates an adequate liquid pool in the common main conduit for low velocity flow of backwash liquid while at the same time providing uninhibited flow of backwash gas.

Abstract: A filter media support system that reduces media clogging and head loss in granular filtration systems by providing a layered porous plate. The porous plate can have multiple layers of fine sized and coarse sized pores. The porous plate is positioned between the media and the filter bottom. The filter media support system is securely anchored to the infrastructure of the underdrain system thereby inhibiting media penetration of the filter bottom and avoiding seal failures. The infrastructure can be air lateral piping fitted beneath the underdrain blocks of the support system. The anchors can be secured to pipe clamps circumscribing the air laterals.

Abstract: Ultrapure water having a reduced amount of TOC and a low electrical conductivity is produced in correspondence with a variation in water quality of raw water. A first water tank has an anaerobic organic matter treatment chamber and an aerobic organic matter treatment chamber which are communicated with each other at their bottom portions. Activated carbon bags are arranged in upper portions of both the chambers, and Bincho charcoal is stowed in the lower portion of the chambers. With this arrangement, carbon compounds and organic nitrogen compounds in the water to be treated are biologically treated by microbes, thereby reducing the TOC. Furthermore, nitrate nitrogen generated through the organic nitrogen compound treatment process is denitrified by the anaerobic microbe, thereby reducing the electrical conductivity of the water to be treated.

Abstract: An underdrain block for a filter media system for supporting the filter media and distributing air and water backwash. The underdrain block comprising a top wall, a bottom wall and two side walls forming an open ended interior. Interior walls, known as lateral separation walls, divide the interior of the block into primary and secondary laterals. When the blocks are laid end to end, the laterals form a common distribution conduit for the transport of air and water backwash. The lateral separation walls can be angular or curved. Curved walls and specifically angled walls increase the area of the laterals. The spacing of the blocks can be approximately 18 inches and the height approximately 8 inches. The underdrain blocks are interlocking to form conduits of up to 40 feet in length.

Abstract: A wastewater treatment system which comprises a tank having defined therein an aerobic treatment zone and a suspended micromedia zone. One embodiment further includes an anaerobic treatment zone. The suspended micromedia zone includes a separating media. Substantially continuous aeration is provided to energize the separating media and cause it to be stirred up into a water column within the tank. The air flow provides partial suspension of the separating media and imparts continual upward motion to the wastewater in such zone. A chimney is provided above a portion of the suspended micromedia zone and extends above the aerobic treatment zone. The mixed liquid and air rising due to the aerator air flow travels within the chimney into the aerobic treatment zone. Some separating media also travels within the chimney into the aerobic treatment zone. Aerobic bacteria is provided in the aerobic treatment zone external of the chimney.

Abstract: A method of backwashing a filter includes a) supplying a backwash liquid via a conduit toward one end of a filter bed; b) aspirating air into the backwash liquid upstream of the bed; c) introducing a mixture of air and backwash liquid into the filter bed at the one end thereof; and d) expelling backwash water and air from an opposite end of the filter bed. A related filter system includes a filter basin having a bed of filter media material therein; a filtrate channel proximate the basin; at least one tubular underdrain header in the bed and in fluid communication with the filtrate channel; and a backwash pump having a backwash water supply conduit selectively engageable with the underdrain header for supplying backwash liquid to the bed. The backwash water supply conduit includes a nozzle for aspirating air into the supply conduit at a location between the backwash pump and the bed.

Abstract: An underdrain unit of the type having air and water backwash for backflushing a granular filtration system has improved retention structure for retaining folded, perforated stainless steel underdrain plates against the floor of the tank drain. The retention structure is in the form of hollow horizontal tubes which not only hold the folded plates in place but also serve to deliver backwashing air. Thus, instead of air delivery tubes being mounted above a series of brackets that hold the folded plates in place against the floor, the air delivery in the system of the invention is via the same structural element which retains the folded plates. Embodiments are described for gravel bed systems and for sand filter systems.

Abstract: A filter with a horizontally fed filter chamber having loose bulk material as the filter medium has a wall on the upstream side and downstream side to hold back the loose bulk material in the filter chamber. The filter chamber includes a compressed air-lift pump disposed inside of the filter chamber for pumping the loose bulk material from a bottom area of the filter chamber, through a bottom lifter connected with a stand pipe to an upper rinse chamber, and a hopper disposed at a bottom of the filter chamber having entrance slots and surrounded by a chamber that is provided with a rinse water inlet tube connected to a raw water chamber.

Abstract: In a fluidized bed filtering apparatus, for preventing particles of filtering material from entering into a feed pipe to clog the feed pipe and lowering the frequency of washing operations, a filtering material layer made of granular filtering material is supported by a supporting layer disposed in a filtering chamber so as to provide a space in the lower portion of the filtering chamber and two lines of a first feed pipe the outlet of which opens in the filtering material layer and a second feed pipe the outlet of which opens within the space are provided for feeding corrupt water into the filtering chamber.