Abstract: An underdrain apparatus and a method for manufacturing such apparatus are provided. The underdrain apparatus can be extruded in long sections as a unitary part. The underdrain apparatus may be extruded in various sizes, shapes, and materials. Further, the underdrain apparatus may include a passageway for transporting water to and from the filter media and/or air to the filter media. In some embodiments, apertures are formed in the underdrain apparatus during an extrusion process to provide a path between the passageway and the filter media.

Abstract: A combination biological contactor and self-backwashing filter system for water treatment is disclosed. The system may include a treatment vessel defining an upper chamber and a lower chamber. A biological contactor may be disposed within the upper chamber, and a filter may be disposed in the lower chamber. A contactor outlet conduit and inlet manifold may be used to transfer water from the biological contactor to filter cells within the filter.

Abstract: A modular underdrain system is disclosed. The modular underdrain system may comprise an intermediate modular component having a first peripheral side including a first mating portion and a second peripheral side including a second mating portion. The second mating portion may be sized and shaped to engage with a first mating portion of an adjacent modular component. A modular component chamber may be bounded by an underdrain floor side and an internal side. The underdrain floor side may comprise a plurality of slots. The metering pipe is sized to be positioned within a metering pipe opening in the internal side with a distributor head positioned within the modular component chamber. The metering pipe may comprise a set of one or more remote orifices and a set of one or more proximate orifices.

Abstract: Water treatment apparatus, including: a ceramic filter; and a flow apparatus operable to pass water through the ceramic filter in a forward direction so as to filter the water, the flow apparatus also operable to pass water through the ceramic filter in a reverse direction so as to remove material from the ceramic filter, whereby material having been deposited by filtration of the water is removed.

Abstract: A fiber filtering apparatus includes: an enclosure including an upper box and a lower box communicating with the upper box; a strainer installed in the upper box along a longitudinal direction; a plurality of fiber yarn media configured to be fixed to upper and lower fixing means each coupled to upper and lower parts of the strainer; a plurality of fiber ball media configured to be embedded in the lower box to form a second filtering layer; a first pipe configured to be formed on one side wall on the lower part of the upper box and introduced with raw water during filtration and drain backwashing water during backwashing; and a second pipe formed on one side wall on a lower part of the lower box and drain filtered water during the filtration and introduced with washing water during the backwashing.

Abstract: A biological reactor for treating wastewater. The reactor includes a gas injection system and a system for directing wastewater into the reactor. Further, the reactor includes a biological filter comprised of a packed bed of biofilm carriers and a volume of moveable biofilm carriers. During the method of treating the wastewater, the wastewater moves upwardly through the reactor and through the biological filter while gas is emitted from the gas injection system.

Abstract: A method of distributing gas and liquid through an underdrain system includes: a) positioning an underdrain system on a filter floor, the underdrain system comprising at least one underdrain block and filter media positioned on top of the underdrain block; b) distributing gas sufficiently evenly through the underdrain system at a rate of less than 2 scfm/ft2 by distributing a liquid at a rate of less than 2 gpm/ft2 concurrently with the gas; c) increasing the distribution rate of the liquid, or increasing the distribution rate of the liquid and the distribution rate of the gas; d) stopping the distribution of gas; e) further increasing the distribution rate of the liquid; and f) decreasing the distribution rate of the liquid. A method of distributing gas and liquid during an upflow filtration mode is also included.

Abstract: An apparatus for use in a filter system for filtering water or wastewater. The apparatus preferably includes at least one underdrain lateral having at least an inner chamber, a first outer chamber and a second outer chamber. The first outer chamber and the second outer chamber are preferably in fluid communication with the inner chamber. The inner chamber, the first outer chamber and the second outer chamber are preferably formed by an inner liner and an outer liner. The outer liner is a separate piece from the inner liner and surrounds the inner liner. The inner chamber is preferably configured to simultaneously receive a liquid and a gas during a washing procedure including simultaneous use of a liquid and gas to clean a filter bed to create a liquid and gas interface in the inner chamber.

Abstract: An apparatus for removing impurities from water and/or wastewater and a method of installing a fluid distribution system in the apparatus. In the most preferred form of the invention, the fluid distribution system is an air scour system for directing air through the filter bed to assist in cleaning of the filter bed to remove impurities trapped in the filter bed during a service run. In the most preferred form, the method of installing the fluid distribution system in the filter bed is performed by imparting a force to the filter bed to permit the fluid distribution system to be installed in the filter bed without removing media. The fluid distribution system is preferably configured to permit the fluid distribution system to be readily installed in the filter bed and at an optimum orientation.

Abstract: An underdrain apparatus and a method for manufacturing such apparatus are provided. The underdrain apparatus can be extruded in long sections as a unitary part. The underdrain apparatus may be extruded in various sizes, shapes, and materials. Further, the underdrain apparatus may include a passageway for transporting water to and from the filter media and/or air to the filter media. In some embodiments, apertures are formed in the underdrain apparatus during an extrusion process to provide a path between the passageway and the filter media.

Abstract: An underdrain system for transferring forces and directing flow includes at least one underdrain block having a top wall, a bottom wall, and two side walls connecting the top wall to the bottom wall to define a block interior. An insert is disposed in the interior of the underdrain block. The insert includes force-transmitting buttresses spaced along an exterior of the insert that contacts the two side walls of the underdrain block and act to transfer downward forces acting on the top wall of the underdrain block and internal fluid forces acting on the insert to the side walls of the underdrain block. The force-transmitting buttresses can also direct hydraulic flow.

Abstract: An apparatus for removing impurities from water and/or wastewater and a method of washing a filter having a filter bed for filtering water or wastewater. In the most preferred form of the invention, the fluid distribution system is an air scour system for directing air through the filter bed to assist in cleaning of the filter bed to remove impurities trapped in the filter bed during a service run. In the most preferred form, the air scour system includes an adapter for permitting adjustment of at least one component of the air scour system during installation.

Abstract: The invention relates to a method for washing a filter (F) having at least two layers of filtering media (4, 5) for raw water containing components having a tendency to form cakes (M), in particular for seawater, the layers of filtering media being supported by a base (6) comprising pass-through openings and provided with nozzles (6a) enabling air and/or wash water to be injected, the raw water flowing through the layers from top to bottom and the treated water being recovered at the lower portion of the filter, and which comprises at least one spillway (D) at the upper portion thereof for collecting the wash water.

Abstract: A packed tower for the absorption of water or SO3 in sulfuric acid includes a jacket and a domed grid disposed within the jacket. The domed grid is held on an L-shaped ring such that a gap is formed between an outside diameter of the domed grid and the jacket. A bed of packings is held on the domed grid through which the sulfuric acid charged from above trickles. A gas supply tube is disposed in a lower region of the tower. A gas outlet is disposed above the bed. An acid outlet is disposed in the lower region of the tower.

Abstract: An apparatus for use in a filter system for filtering water or wastewater. The apparatus includes at least one underdrain lateral. The at least one underdrain lateral has at least an inner chamber, a first outer chamber and a second outer chamber. The first outer chamber and the second outer chamber are preferably in fluid communication with the inner chamber. The inner chamber, the first outer chamber and the second outer chamber are preferably formed by an inner liner and an outer liner. The outer liner is a separate piece from the inner liner and surrounds the inner liner. The inner chamber is preferably configured to simultaneously receive a liquid and a gas during a washing procedure including simultaneous use of a liquid and gas to clean a filter bed to create a liquid and gas interface in the inner chamber.

Abstract: An underdrain filter block for use in draining and backwashing a filtering media in a filter bed includes a top wall, a pair of side walls extending from the top wall, a bottom wall extending between the pair of side walls, and a transverse wall extending from one of the pair of side walls to the other of the pair of side walls. The top wall, the pair of side walls, and the bottom wall define an upper portion and a lower portion. The lower portion includes a grout chamber positioned between the bottom wall and the transverse wall and at least one of the bottom wall and said side walls contains an opening.

Abstract: A filter system having a filter bed for filtering water or wastewater, where the filter bed is periodically washed between service runs by directing washing liquid and washing gas upwardly through the filter bed. The filter system includes a filter bed and at least one flume. The flume is in fluid communication with the filter bed. Preferably, the flume is configured such that no washing liquid and washing gas interface is present in the flume. The flume may be configured such that during washing of the filter bed between service runs the flume receives a washing gas and directs the washing gas upwardly through the filter bed to assist in cleaning the filter bed between service runs. The flume may further be configured such that during washing the only liquid directed from the flume to the filter bed is residual liquid that may be present in the flume from a prior service run.

Abstract: An apparatus for removing impurities from water and/or wastewater and a method of washing a filter having a filter bed for filtering water or wastewater. In the most preferred form of the invention, the fluid distribution system is an air scour system for directing air through the filter bed to assist in cleaning of the filter bed to remove impurities trapped in the filter bed during a service run. In the most preferred form, the air scour system includes an adapter for permitting adjustment of at least one component of the air scour system during installation.

Abstract: A filter system for filtering a liquid containing particles including a single media retainer plate having a top and bottom surface, and defining at least one hopper-shaped compartment having a sloped wall defining a slot spanning the top and bottom surfaces is disclosed. The plate also includes at least one baffle extending from the bottom surface and filter media disposed on the top surface. During a filtering operation of the filter system, the filter media captures the particles, such as dirt, from the liquid as the liquid passes through the filter media to an underdrain system. During a backwash operation of the filter system, the baffle is adapted to direct a backwash fluid in a vertical direction through the slot so that the backwash fluid actuates the filter media to scour the top surface of the plate and prevent the build-up of biological scaling on the plate.

Abstract: [Object] It is an object of the present invention to provide a filtering apparatus capable of efficiently filtering a large volume of to-be filtered water, in which its filtering material is less prone to be clogged, and even if the filtering material is clogged, it is possible to wash the filtering material. [Solving Means] An upward-type filtering apparatus (1) includes a pressure container (2) and a filtering material (3) made of gravels, filtering sands or particles.

Abstract: Systems and methods for separating mine tailings from water-absorbing polymers and regenerating the separated water-absorbing polymers. The systems and methods include a separation assembly that is configured to receive an augmented mine tailings slurry that includes mine tailings, water, and a swollen water-absorbing polymer. The separation assembly separates the swollen water-absorbing polymer from the augmented mine tailings slurry to produce a dewatered mine tailings slurry. The systems and methods further include a water-absorbing polymer regeneration unit that is configured to receive the swollen water-absorbing polymer. The water-absorbing polymer regeneration unit at least partially releases water from the swollen water-absorbing polymer to produce a regenerated water-absorbing polymer, and as a separate output or product, the released water.

Abstract: Method for the removal of organic components from a mixture of organic components and water, characterized in that it comprises the steps of guiding the mixture through at least one vessel (3) in which has been provided an amount of organoclay (17) in at least one removable casing (18) which is permeable to liquids and gasses but not to organoclay particles, or on a supporting structure (28) from where the organoclay particles cannot come off, such that the amount of organoclay particles is at any time part of a removable entity; and of producing a flow through the aforesaid mixture in this vessel (3) by guiding a flow of gas bubbles through this mixture.

Abstract: The present invention relates generally to a system and method for treating wastewater in a filter media apparatus having a draft tube system. The filter media may be walnut shell media.

Abstract: An apparatus for treating a liquid containing impurities may comprise: a filtering chamber for receiving liquid containing impurities, the filtering chamber containing granular media and configured to permit the granular media to interact with the liquid containing impurities, thereby removing impurities from the liquid to produce filtrate; a filtrate section in communication with the filtering chamber for receiving the filtrate, the filtrate section being in communication with a first outlet for outflow of the filtrate; a gas supplying system for delivering gas to the granular media in the filtering chamber for transport of a portion of the granular media to a granular media washer; and a reject section in communication with the granular media washer for receiving a reject mixture comprising liquid and impurities from the granular media washer. The reject section may be in communication with a second outlet for outflow of a portion of the reject mixture.

Abstract: Water treatment apparatus includes raw water special air mixing nozzles (7); filtering tank (5) housing filter layer (4) including two layers of upper layer (2) and lower layer (3), the upper layer including a filter medium with a smaller specific gravity and a larger particle size than a filter medium of the lower layer; a water collection pipe (13) removing filtered water and supplying reverse cleaning water to the filter layer during reverse cleaning; drainage trough (12); and upper layer cleaning apparatus (10), in which the upper layer cleaning apparatus includes upper layer cleaning pipe support member (17), upper layer cleaning water pipe (18), surface-cleaning special air mixing nozzles (19), air suction pipe (20), and horizontal air pipes (31 and 32) and the raw water special air mixing nozzles (7) are attached to raw water inflow tank (70) provided on a part of the drainage trough (12)

Abstract: A method of distributing gas and liquid through an underdrain system includes: a) positioning an underdrain system on a filter floor, the underdrain system comprising at least one underdrain block and filter media positioned on top of the underdrain block; b) distributing gas sufficiently evenly through the underdrain system at a rate of less than 2 scfm/ft2 by distributing a liquid at a rate of less than 2 gpm/ft2 concurrently with the gas; c) increasing the distribution rate of the liquid, or increasing the distribution rate of the liquid and the distribution rate of the gas; d) stopping the distribution of gas; e) further increasing the distribution rate of the liquid; and f) decreasing the distribution rate of the liquid. A method of distributing gas and liquid during an upflow filtration mode is also included.

Abstract: The present invention relates generally to a system and method for treating wastewater in a filter media apparatus having a draft tube system. The filter media may be walnut shell media.

Abstract: An apparatus for treating a liquid containing impurities may comprise: a filtering chamber for receiving liquid containing impurities, the filtering chamber containing granular media and configured to permit the granular media to interact with the liquid containing impurities, thereby removing impurities from the liquid to produce filtrate; a filtrate section in communication with the filtering chamber for receiving the filtrate, the filtrate section being in communication with a first outlet for outflow of the filtrate; a gas supplying system for delivering gas to the granular media in the filtering chamber for transport of a portion of the granular media to a granular media washer; and a reject section in communication with the granular media washer for receiving a reject mixture comprising liquid and impurities from the granular media washer. The reject section may be in communication with a second outlet for outflow of a portion of the reject mixture.

Abstract: A water treatment system (50) utilizing granular activated carbon (GAC) for the removal of organic contaminants in a process water circuit (52), and including a carbon regeneration circuit (54) in fluid communication with the process water circuit. The carbon regeneration circuit may include a dedicated regeneration vessel (16), or the regeneration process may proceed within a GAC/water contactor (58) of the process water circuit. A process is described wherein spent GAC from the water treatment system is regenerated within the system with an oxidation process that minimizes damage to the carbon granules.

Abstract: A filtration and demineralization apparatus 10 including a vessel 20 in a form of a body of revolution; a hollow columnar body 40 that is located in an internal space of the vessel 20, one end 40a of the columnar body being connected to an inner surface of the vessel 20 along an entire circumference of the end, and the other end 40b of the columnar body forming an opening; and a partition plate 44 that is connected to the other end 40b of the hollow columnar body along an entire circumference of the other end 40b, the partition plate being configured to separate an inside space or an outside space of the hollow columnar body 40 as an independent space in the vessel. The partition plate 44 has a circulation port 43 that allows water that is to be treated to pass therethrough.

Abstract: A filter for removing at least some impurities (e.g. foreign matter of any nature including a solid, a liquid or a gas) from water or wastewater. A vibrator operably associated with at least a portion of the filter for imparting a vibrational force to enhance any one or more of numerous aspects of the filtration process including: (i) installation of the filter and/or various components thereof; (ii) servicing of the filter and/or components thereof; and, (iii) operation of the filter during a filtration cycle and a cleaning cycle.

Abstract: An apparatus for use in a filter system for filtering water or wastewater. The apparatus includes at least one underdrain lateral. The at least one underdrain lateral has at least an inner chamber, a first outer chamber and a second outer chamber. The first outer chamber and the second outer chamber are preferably in fluid communication with the inner chamber. The inner chamber, the first outer chamber and the second outer chamber are preferably formed by an inner liner and an outer liner. The outer liner is a separate piece from the inner liner and surrounds the inner liner. The inner chamber is preferably configured to simultaneously receive a liquid and a gas during a washing procedure including simultaneous use of a liquid and gas to clean a filter bed to create a liquid and gas interface in the inner chamber.

Abstract: A filter for removing at least some impurities (e.g. foreign matter of any nature including a solid, a liquid or a gas) from water or wastewater. A vibrator operably associated with at least a portion of the filter for imparting a vibrational force to enhance any one or more of numerous aspects of the filtration process including: (i) installation of the filter and/or various components thereof; (ii) servicing of the filter and/or components thereof; and, (iii) operation of the filter during a filtration cycle and a cleaning cycle.

Abstract: A filter system having a filter bed for filtering water or wastewater, where the filter bed is periodically washed between service runs by directing washing liquid and washing gas upwardly through the filter bed. The filter system includes a filter bed and at least one flume. The flume is in fluid communication with the filter bed. Preferably, the flume is configured such that no washing liquid and washing gas interface is present in the flume. The flume may be configured such that during washing of the filter bed between service runs the flume receives a washing gas and directs the washing gas upwardly through the filter bed to assist in cleaning the filter bed between service runs. The flume may further be configured such that during washing the only liquid directed from the flume to the filter bed is residual liquid that may be present in the flume from a prior service run.

Abstract: A wastewater treatment system comprising one apparatus (1) for de-nitrification and effluent solids removal, another apparatus (2) for biological main treatment, and a further apparatus (3) for solids removal (5), each apparatus including a volume (40) in which each process is performed, a media-retaining sieve (6) at the volume (40) and arranged to retain buoyant media particles (4) in the volume (40), and a gas sparging device (8), (9) which is located in a lower end region of the volume (40) and which is controllable by way of valves (11) and (15). The three volumes (40) are substantially (10) identical to, or multiples of, each other, the three sieves (6) are substantially identical to each other, and the three sparging devices (8), (9) are substantially identical to each other. The gas is sparged into the main treatment bed at a lower flow rate for wastewater aeration but intermittently at a higher flow rate to disrupt and clean the bed.

Abstract: A backwash distribution apparatus for a filter having a filter tank and a plurality of underdrain laterals includes a first and second separator device positioned in a common main conduit to define first and second auxiliary flumes. The first and second auxiliary flumes are in fluid communication with the common main conduit and the underdrain laterals. The first separator device has at least one flume liquid metering orifice preferably located near the bottom of the first separator device so that it may be below a gas liquid interface in the first auxiliary flume. The second separator device has either a weir edge or a plurality of metering orifices (or both) for passing backwash liquid from the common main conduit into the second auxiliary flume.

Abstract: A water filtration apparatus has at least one tank in fluid communication with a conduit through at least one aperture in a wall. Each tank uses filter blocks to support the filter medium and to direct the filtered water to the conduit via the aperture. An end plate for the filter block is provided, the end plate being adapted to seal against a free end of the filter block. The end plate also provides apertures for fluid flow into and out of the filter block, and a device for receiving a sealant to provide a seal between the end plate and the wall. The end plate improves the installation of the apparatus, and the sealant improves the reliability of the seal round the apertures, which in turn improves the efficiency of a backwash operation used to clean the filter medium.

Abstract: A filtration unit (A) is immersed in raw water (W) that is held inside a reservoir tank, and includes a membrane module (5) that filters the introduced raw water (W). This filtration unit (A) includes a casing (3) which is in the shape of a box having a bottom and includes the membrane module (5) housed therein, and an activated carbon cartridge (4) inside which activated carbon is provided in cartridge form. Inside the casing (3) are provided an intake port that is used to introduce the raw water into the interior of the casing, and an opening/closing device that is installed on this intake port and controls a flow of the raw water into the interior of the casing, and the activated carbon cartridge (4) side and the membrane module (5) side are separated so as to allow the raw water (W) introduced into the interior of the casing 3 to circulate from the activated carbon cartridge (4) side to the membrane module (5) side.

Abstract: A water treatment apparatus includes a raw water supply tube, mixed raw water stream jet nozzles each communicating at one end thereof with the raw water supply tube and having at the other end thereof a raw water outlet from which mixed stream of raw water and air is jetted out, a filtering tank housing a filter layer disposed below the mixed raw water stream jet nozzles with a predetermined distance between the surface of the filter layer and the raw water outlet of the mixed raw water stream jet nozzles, a filtered water takeout tube provided in the filtering tank for taking out water filtered through the filter layer, a reverse stream cleaning water supply tube provided in the filtering tank for supplying reverse stream cleaning water to the filter layer, filter layer cleaning jet nozzles each communicating at one end thereof with a filter layer cleaning water supply tube and having at the other end thereof a cleaning water outlet from which cleaning water is jetted out, and an overflow outlet provided in

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 system and method for uniformly distributing fluids (e.g., washing and in-service) through a filter bed of a filter. The system and method of the present invention can be used with any type of filter that uses media to remove impurities from a fluid. The filter bed can include one or more layers of media. The media can be natural (e.g., sand, gravel, anthracite, etc.) or can be fabricated (e.g., plastic). The filter media can be supported by one or more layers of gravel. Alternatively, the filter media can be supported by a porous plate or other support designed to replace the gravel layers. The present invention includes a system having one or more distribution members configured to uniformly distribute a fluid through a filter bed of a filter. Preferably, the one or more distribution members can be readily installed by relatively unskilled labor in both existing filters and new filters.

Abstract: The present invention relates generally to a system and method for treating wastewater in a filter media apparatus having a draft tube system. The filter media may be walnut shell media.

Abstract: Exemplary systems and methods relating to washboxes are described.

Abstract: A system and method for uniformly distributing fluids (e.g., washing and in-service) through a filter bed of a filter. The system and method of the present invention can be used with any type of filter that uses media to remove impurities from a fluid. The filter bed can include one or more layers of media. The media can be natural (e.g., sand, gravel, anthracite, etc.) or can be fabricated (e.g., plastic). The filter media can be supported by one or more layers of gravel. Alternatively, the filter media can be supported by a porous plate or other support designed to replace the gravel layers. The present invention includes a system having a distribution member configured to uniformly distribute a fluid through a filter bed of a filter. Preferably, the distribution member can be readily installed by relatively unskilled labor in both existing filters and new filters.

Abstract: Exemplary systems and methods relating to washboxes are described.

Abstract: A method and apparatuses are presented for rejuvenating a bed of granular filter medium that has accumulated contaminants during filtration of a liquid stream. The method first includes the step of establishing a small volumetric flow rate of clean filtrate in reverse flow. Then, the filter media is agitated to break-up contaminants that have become agglomerated on the surface of or within the interstitial spaces of the filter media. The agitating step is accomplished by exposing the liquid-full filter media to a jetting stream comprised mostly of a gas mixed with a clean liquid. The jetting stream is dispersed throughout the filter media through a plurality of radial nozzles located within the filter bed. The radial nozzles disperse the gas within the liquid and filter media causing sufficient turbulence and agitation of the filter media granules to liberate the trapped contaminants without the need for high liquid flow rates.

Abstract: A filter system having a filter bed for filtering water or wastewater, where the filter bed is periodically washed between service runs by directing washing liquid and washing gas upwardly through the filter bed. The filter system includes a filter bed and at least one flume. The flume is in fluid communication with the filter bed. Preferably, the flume is configured such that no washing liquid and washing gas interface is present in the flume. The flume may be configured such that during washing of the filter bed between service runs the flume receives a washing gas and directs the washing gas upwardly through the filter bed to assist in cleaning the filter bed between service runs. The flume may further be configured such that during washing the only liquid directed from the flume to the filter bed is residual liquid that may be present in the flume from a prior service run.

Abstract: A flume for a filter system including at least one filter having a filter bed that is periodically washed with liquid, gas and/or a combination of liquid and gas. The flume includes a chamber having a top wall, a bottom wall, a left sidewall and a right sidewall. The chamber is adapted to receive a liquid, a gas and/or a combination of liquid and gas. Preferably, the flumes includes at least a first inner wall and a second inner wall. Each of the first inner wall and the second inner wall are preferably free of any orifices. The first inner wall is positioned relative to the second inner wall such that an open space is formed between the first inner wall and the second inner wall. The open space creates a first liquid/gas interface upstream of the first inner wall and the second inner wall and a second gas/liquid interface downstream of the first inner wall and the second inner wall when gas and liquid are present in the chamber.

Abstract: A downflow sand filter used for treating wastewater which has degraded in function from its original design is at least in part rejuvenated by flowing air downwardly through the bed during time when flow of wastewater is ceased. The low velocity air flow helps dewater the bed and leads to the removal of accumulated organic material which has clogged the pores of the bed. In accord with different embodiments, air flow is alternated with water flow in particular ways, for instance, so the water flow is sufficient to create ponding or is sufficient to maintain moisture content within the bed.

Abstract: A system and method for uniformly distributing fluids (e.g., washing and in-service) through a filter bed of a filter. The system and method of the present invention can be used with any type of filter that uses media to remove impurities from a fluid. The filter bed can include one or more layers of media. The media can be natural (e.g., sand, gravel, anthracite, etc.) or can be fabricated (e.g., plastic). The filter media can be supported by one or more layers of gravel. Alternatively, the filter media can be supported by a porous plate or other support designed to replace the gravel layers. The present invention includes a system having a distribution member configured to uniformly distribute a fluid through a filter bed of a filter. Preferably, the distribution member can be readily installed by relatively unskilled labor in both existing filters and new filters. The distribution member is preferably configured to occupy only a small percentage of space in a distribution chamber (e.g., a flume).