Abstract: A regenerative filter having particular application for removal of oil from water. The filter includes a bed of finely divided particles or media separated in three horizontal layers. The top layer is comprised of anthracite particles, the middle layer of silica sand particles, and the bottom layer of garnet sand particles. The filter bed is supported within the filter vessel by a strata of relatively coarse support particles located beneath the bottom layer of filter media. The oil-contaminated water is fed into the top of the vessel and flows through the filter bed and supporting strata to a manifold at the bottom of the tower where it is discharged. By proper selection of the type and size of the media, effective removal of oil from the water is achieved during filtering and loss of media and intermixing of the layers is prevented during the back washing cycle.

Abstract: A water filter includes a main housing defining a primary filter chamber in which is disposed an elongated tubular inner or secondary filter. Media arranged in the direction of flow includes, within the primary filter, layers of relatively coarse and fine flint gravel followed by a substantial layer of packed charcoal. The inner filter includes a substantial layer of packed charcoal and discrete layers of fine and coarse gravel near the outlet of the inner filter. The arrangement of media provides for repeated backflushings without contaminating the primary filter media. The main filter housing includes spaced apart head members which are interconnected by cylindrical tubular liners and an outer tubular shell disposed around the inner liners. The filter inlet and outlet conduits are provided with self-sealing quick disconnect coupler members for coupling the filter to a diverter circuit from the main water line or to a suitable circuit for backflushing operations.

Abstract: The upflow filter assembly includes a primary chamber situated above a secondary chamber within an enclosure and having a filter element spanning the primary chamber towards the upper end thereof. Airlocks are situated near the dividing floor of the two chambers so that when in the liquid treating or filtering mode, they operate to maintain the air/liquid interface between the chambers and prevent liquid from passing into the secondary chamber assisted by compressed air introduced into the secondary chamber. Liquid containing solids and/or flocculents, is fed into the primary chamber adjacent the lower side thereof and gradually fills the chamber with much of the flocculents and solids settling out by gravity. The partially deflocculated liquid then passes up through the filter element to a height above the filter element with excess, relatively clear effluent flowing out through an outlet spaced above the filter element to provide a hydraulic head above the filter element.

Abstract: A device for the distribution of water to be treated into and for the recovery of washing liquid from a water treatment filter apparatus of the type including a tank containing therein a filter material includes a channel coupled to and extending along the length of the tank, the channel receiving therein water to be treated. The channel has an opening into the interior of the tank at a level above the filter material. The opening is defined at the lower portion thereof by an overflow over which the water to be treated flows from the channel to the tank. The overflow includes a first inclined plane inclined downwardly and away from the channel in a direction toward the tank and a second inclined plane inclined downwardly and toward the channel from the first inclined plane. The inclined planes extend into the tank and form a deflector structure to prevent any filter material from passing through the opening during backwashing of the filter material.

Abstract: A self-supporting underdrain unit to be placed upon the substantially horizontal floor of a filter tank to provide a liquid filtration system is disclosed. The self-supporting underdrain unit provides separately controllable fluid and exhaust gas header systems for backwashing. The exhaust gas and backwashing fluid are mixed in a turbulent mixing zone to provide superior backwashing and cleansing action.

Abstract: A hydrophilic oleophobic filter medium in granular form and composed of glass beads dispersed in a matrix of cured cement. The granules may be utilized in conjunction with naturally occurring materials, e.g., sand and/or anthracite. The granular density can be predetermined and varied. The granular shape is regular and controllable and the granular size can be graded for each density, so that the granules in a given filter level are of varient size, having a uniformity coefficient ranging from about 1.2 to 1.7. The method of making such granules includes the steps of casting a sheet of desired density and thickness, partially curing the sheet, severing the partially cured sheet to polygonal granules, curing the granules, optionally tumbling the granules, and finally screening them for final sizing.

Abstract: For removing iron from water the present apparatus has a bed of manganese zeolite particles above an outlet screen unit and below an inlet screen unit in a container. The container has enough empty space above the treatment bed to permit substantially all of its particles to be tumbled vigorously during backwash for effective removal of the accumulated iron and other impurities trapped in the treatment bed. Each screen unit includes a pair of split rings which hold foraminous screens between them and are radially contractable for slidable insertion in the container, after which they expand radially for a tight fit inside the container. Cross bars on each split ring reinforce the screens.

Abstract: There is described a device comprising a filtering compartment enclosing a filtering body, an inlet for unfiltered water and an outlet for filtered water, said inlet being preceded by a liquid-receiving compartment which communicates with a container containing a sterilizing product at a level lower than the highest permissible water level inside said receiving compartment and above the filtered water outlet level.

Abstract: A high efficiency domestic furnace incorporates means for separating and neutralizing flue gas condensate. Acidic condensate from the flue gas products of combustion is neutralized by contact with neutralizing material in a housing through which the condensate is flowed. The use of the neutralizer in connection with a high efficiency domestic furnace permits discharge of the condensate directly to the household drain. The neutralizer is arranged to be self-flushing and defines a serpentine, series flow path and is arranged to discharge the neutralized condensate as a result of the entry of additional acidic condensate at its inlet.

Abstract: A lagoon for wastewater treatment, having an aeration zone and a quiescent zone is provided with a collector in the form of a horizontally extending submerged tube filled with biological reaction media and having an array of openings on its underside for the entry of water into its interior. The collector tube is supported at its ends by vertical pipe sections extending upwardly from the floor of the lagoon. These pipe sections connect the ends of the collector tube to a discharge conduit. Provision is made for the introduction of air into the collector for backwashing the biological reaction media. The media within the tube, in cooperation with openings designed to produce a velocity gradient within a limited range, insure uniform flow and minimum disturbance of the quiescent zone so that a highly clarified effluent is produced. The biological media also provide a large surface area for the growth of nitrifying bacteria.

Abstract: A treatment column includes a treatment zone which is completely filled with a bed of granular treatment material. A normal treatment operation includes passing a fluid to be treated in a downward direction through the bed of treatment material, thereby treating the fluid. Solid particles suspended in the fluid are removed by the upper portion of the bed of treatment material and are retained therein. Regeneration of the bed is achieved in a countercurrent direction within the treatment column. Retained solid particles are removed from the upper portion of the bed by periodically removing the upper portion only of the bed from the treatment column and transferring such upper portion to a separate washing column whereat the portion of the bed is cleaned and washed. The thus cleaned and washed treatment material is then returned to the upper portion of the treatment zone within the treatment column to replenish the bed.

Abstract: An apparatus for separating suspended solids from a liquid includes a tank, a floating bed of granular filter material held at the upper portion of the tank at the time of filtration, a feed pipe for feeding the liquid at a position between a filtering section and a sedimenting section, a hollow member or members which are arranged within the tank at a position below the position of the filter bed but above the position of the feed pipe, an air supply pipe which blows air up through the hollow member or members, thereby creating a turbulence required for effective backwashing, an arrangement for bringing the filter bed down to a position where the lowermost surface of the filter bed is held below a position substantially flush with the top end of the hollow member or members, a means for discharging a filtrate from the tank which is arranged in the top portion thereof, and a means for discharging a deposit of the suspended solids from the tank, which is equipped at the bottom portion thereof.

Abstract: There is disclosed a method of filtering liquids in a vertical tower filter tank with a flat bottom and liquid inlet and outlet means for flowing liquid under pressure into a sand filter column in the tower tank causing the liquid to flow through distribution gaps which direct the flow horizontally through the filter into a collection pipe and upward out the outlet. In addition the filter is regenerated by backflowing washwater under pressure so the filter grains are slurried and the impurities are removed therefrom and washed out an overflow outlet. The apparatus for conducting the filtering and regeneration are also disclosed. The apparatus has a flat bottom and at least one perforated wall to divide the filter column into sections. There is an inlet for the washwater having a speed accelerating throat.

Abstract: A fluid treating apparatus and method are provided which employ finely subdivided surface active particles arranged in loose bed form and confined within a treating tank by means which prevent the escape of such particles but which permits fluid flow therethrough at a high rate with a minimum pressure drop. In an important embodiment, the apparatus and method of this invention are particularly directed to the treatment of water with fine mesh ion cation exchange resin particles of below 50 mesh size, and preferably 100 to 200 mesh or smaller, measured on a dry basis.

Abstract: An upflow filter usable with a home sewage treatment plant, and including a container therefor. The container comprises a dividing wall extending thereacross dividing it into first and second filtering chambers, each of which has a grating therein serving to divide each filtering chamber into top and bottom portions. Each grating is adapted to support thereon a filtering media. The container has an inlet and an outlet, with there being provided a vertical opening or passage in the dividing wall in communication with said inlet, and with such passage having lateral exit openings communicating the vertical passage with the respective filtering chamber, adjacent the bottom thereof. A well is provided in the dividing wall downstream from the vertical passage.

Abstract: A filter for filtering contaminants from liquid, wherein the apparatus includes several distinct, adjacent layers of granular filter medium. The layers are carefully graded for size and density, with the granules constituting the layers increasing in density and decreasing in size in the direction of filter flow. At least some of the layers are composed of essentially uniformly sized and shaped, water-wettable synthetic granules of a specific gravity ranging from about 1.04 to about 1.5. For some applications, all of the bed layers are formed of such synthetic granules; for other applications, some of the layers, preferably the lower layers, are formed of naturally occurring materials, such as anthracite, sand, and fruit pit shells or nut shells. In either form of the invention, the distribution of density and size in the direction of flow--normally downwardly--is such that the layers readily stratify after backwashing to reconstitute the bed in its initial, most efficient filtration configuration.

Abstract: An apparatus for filter backwashing includes a vessel containing a bed of filter media. Laterals with nozzles are disposed below the filter media to convey backwashing air and water into the filter bed. Below the laterals are located a manifold and a distribution plenum to carry air into the laterals. The manifold and the distribution plenum are separated by a common wall having a plurality of ports to provide communication therebetween. Communication between the distribution plenum and the laterals is provided by a plurality of conduits, one conduit extending into each lateral from the distribution plenum.

Abstract: A separator suitable for the separation of a first liquid of relatively lower specific gravity and a second liquid of relatively higher specific gravity from a liquid mixture containing both liquids, the liquids being mutually immiscible, the separator comprising an inlet for introducing the mixture into a first separation zone so constructed and arranged as to promote the separation by gravity of a substantial part of the first liquid from the mixture, a first liquid outlet for the discharge of separated first liquid from the separator, a second liquid outlet for the discharge of separated second liquid from the separator, means for causing first liquid separated in the first separation zone to pass to the first liquid outlet, means for causing the remaining liquid mixture containing a minor proportion of the first liquid and a major proportion of the second liquid to pass towards the second liquid outlet along a flow path including a part extending downwardly through a second separation zone partially fille

Abstract: A treatment facility has a granular media bed for use in acting upon (e.g. filtering) liquid mixtures, such as industrial and municipal water and wastewater, and employs a backwash operation between treatment operations for cleaning or otherwise enhancing the quality of the bed. A control system for the backwash operation establishes a first backwash rate for washing and scouring the granular media to release suspended solids and/or other impurities from the bed. Thereafter the control system establishes a second and generally greater rate for removing the released impurities from the facility. Preferably the first rate is chosen to just completely fluidize the granular bed, at which point a pressure responsive control system detects a constant differential pressure (i.e. a zero change in differential pressure), and the second rate, which generally is greater than the first rate, is responsive to the temperature of the backwash liquid.

Abstract: Apparatus for the treatment of wastewater has an enclosed unit providing a facultative zone wherein a mixture low in dissolved carbon comprising raw sewage and partially processed sewage undergoes denitrification brought about by faculative organisms contained in the prevailing low oxygen environment. Effluent from the facultative zone is charged into an enclosed columnar oxidation unit where a controlled flow of air or oxygen oxidizes nitrogen compounds present in raw sewage into nitrates. Part of the effluent from this columnar oxidation unit wherein the limited flow of oxygen has been mostly consumed in oxidizing the nitrogen compounds and is low in dissolved oxygen is recycled to the facultative zone and part flows into a columnar denitrification zone wherein anaerobic microorganisms substantially completely remove nitrogen as gas from the nitrates producing an effluent with a low nitrate content. Columnar oxidation units and denitrification units are in essentially deep-bed filters.

Abstract: An adsorbtion filter for water including a housing containing a plurality of layers of granules of different types of activated carbon material with the carbon material of a respective layer having substantially the same mesh size, apparent density and adsorbtive capacity, the layers being juxtaposed and the materials of the respective layers having decreasing internal pore size and increasing indices of retentivity proceeding in a direction from the inlet to the outlet of the filter.

Abstract: Herein disclosed is a floating skimming apparatus for removal of contaminated particles from the surface of a liquid contained in a tank. The floating skimming apparatus comprises a deflecting chamber extending substantially the width of the tank, movable along the length of the tank, and has at least one vertex for collecting deflected contaminated particles upon movement of the deflecting chamber. Flotation collars are connected to the deflecting chamber for continuously maintaining a portion of the deflecting chamber above the surface of the liquid. An evacuation device is connected to the deflecting chamber at the vertex for collecting the contaminated particles and removing the contaminated particles from the tank.

Abstract: Polluted waste water is combined with preferably shredded trash including organic trash components to form a water-trash mixture from which inorganic substances such as sand are initially gravitationally setted out and removed. The trash-water mixture is then passed into a roughing filter constructed of a plurality of individual, replaceable filter elements stocked with non-activated carbon to remove floating and suspended particulate matter from the mixture. Thereafter, the water is flowed through a fine filter, also constructed of individual filter elements but stocked with activated carbon for the removal of remaining particulate matter as well as dissolved substances. The filter elements are intermittently regenerated by heating the coal and the residue deposited thereon under an oxygen deficiency to degas organic matters of the residue and form additional filter carbon, both non-activated and activated carbon.

Abstract: In the filtration cycle, a fluid such as water containing suspended solid waste matter is treated with a coagulating agent and gravity-fed through a plurality of individual filter cells, or modules, containing a particulate, coarse, granular filter media. Backwashing is effected by injecting water into the filter media at the bottom center of the cell, causing the filter media to well upwardly and to form on the surface a series of polarly oriented ridges and troughs, the troughs serving to guide "mudballs" and coagulant particles on the media into an inlet port connected to the injector pipe where the high pressure water breaks up the mudballs into manageable particle sizes and scours the media. Solid particles suspended in the water overlying the media are drawn off through a backwash overflow and are fed into a clarifier where separation is effected and clarified water is provided for re-injection into the media.

Abstract: An adsorption-regeneration column section is provided for treating a fluid effluent. A column section has means, which do not contact the adsorbent, for feeding an effluent into the column section and a means for uniformly distributing the effluent across the column diameter at the inlet thereof. An adsorbent is supported within the column section and occupies less than the entire column section. The column section is further provided with means for removably connecting a second column section with said column section along a single vertical axis without substantially restricting the flow path of the effluent. When two of the column sections are joined each having adsorbent therein, a staging space is provided between the adsorbents within the column sections for disengagement of the effluent from the adsorbent.

Abstract: The invention discloses an improved granular media filter of the type including a filter tank, means for dividing the tank into a plurality of cells, means within each cell for holding horizontal porous support plates, a bed of filter media on the porous support plates, influent means for delivering fluid to be treated to the top of the filter bed, filtrate receiving means in each cell below the support plates for receiving the treated fluid, an effluent channel for removing the treated liquid from the filter, port means for delivering the treated liquid from each filtrate receiving means to the common effluent channel and backwashing means that cooperate with the port means to force a backwashing liquid back through the port means and filtrate receiving means and up through the filter bed for removing contaminants therein and thereon.

Abstract: A vacuum filter for vacuum flow filtration through a filter bed of water from a swimming pool is provided, comprising an open-top tank; a filter bed of particulate material in the tank; fluid flow connections communicating the tank with a water recirculation system for the swimming pool, one adjacent an upper portion and one adjacent a lower portion of the filter bed; an inlet line communicating the swimming pool with the tank and maintaining the level of water in the tank at a level corresponding to a level of water in the swimming pool, thereby providing a head of water for gravity backwash flow through the filter bed, and valves controlling flow into the tank via the fluid flow connections between the tank and the inlet line, and between the tank and the water recirculation system; and a direct fluid flow connection communicating a gutter drain of the swimming pool with the tank; a vacuum is drawn downstream of the filter bed by a pump recirculating filtered water to the swimming pool.

Abstract: A sewage treatment system is divided into two stages with a collection system dispersed therebetween. The first stage includes anoxic treatment units producing an anaerobic effluent which is moved through the vacuum tight collection system to the second stage of treatment including an oxidation unit producing an aerobic effluent containing nitrates, dissolved oxygen and activated sludge. The two liquids are mixed in a chamber and are subjected to treatment before discharge for producing a highly treated effluent from which a major part of the nutrients have been removed.

Abstract: A filter for cleaning a flow of liquid including a tank divided into upper and lower chambers by a support element for a filter material bed. In one embodiment, the support element includes a corrugated plate which may be either self-supporting or supported by a header and, in another embodiment, the support element includes a flat plate supported by beam elements which in turn may be supported by the header. Another feature of the filter is the provision of an influent filter liquid inlet assembly including a self-closing passage which normally opens into the tank upper chamber and which closes when the upper tank chamber is filled to a predetermined level with backwash fluid during reverse flow backwashing of the filter bed.

Abstract: Placed in the ground adjacent a conventional septic tank are a purification tank, which contains a smaller, cylindrical filter tank, and a plurality of spaced, parallel, vertically-disposed ozonating tanks, which are located in an annular space between the filter tank and the purification tank. Perforated diffusers in the lower ends of the ozonating tanks are connected to an ozone generator which intermittently supplies ozone gas to the diffusers. Liquid effluent from the septic tank is fed to the lower end of the filter tank and passes upwardly through a removable, porous filter, then successively through the ozonating tanks, then into the space or reservoir formed in the purification tank around the outsides of the filter tank and ozonating tanks, and finally through an overflow outlet to a surrounding leach field. Excess ozone gas is piped from the upper ends of the ozonating tanks back to the septic tank to increase the effectiveness of the septic tank.

Abstract: Disclosed herein is a method for cleaning a filter device packed with a bed of filtering grains, which cleaning is effected whenever the pressure loss in the filter device has increased to a prescribed level by first discharging the filtering grains through the upper side of the device in conjunction with a current of water, then circulating the filtering grains back into the device via the lower side thereof and giving the freshly formed bed of filtering grains a backwashing with water.

Abstract: A baffle and wash trough assembly is provided for reducing media loss during high-turbulence washing of granular-media filters. The assembly includes a water collection trough having an overflow weir on at least one side thereof and a lower portion with downwardly and inwardly converging sides, and a baffle supported adjacent one side of the trough; the baffle having an upwardly concave arcuate portion in opposed relation to the trough lower portion, and defining a restricted flow channel for the wash water to the trough. There may also be provided a second baffle supported adjacent the other side of the trough and having an upwardly concave arcuate portion in opposed relation to the other side of the trough lower portion. The lower end of the second baffle preferably terminates above and inwardly of the lower end of the first baffle, thereby defining a second channel for removal of backwash water.

Abstract: Two vertical flow filters for carrying out various methods for rapidly fluidizing a plug are disclosed.An apparatus comprises a vertical elongated granular media filter having vertically spaced apart plug-breaking-up jets on one side from top to bottom for ejecting high pressure fluid horizontally at the plug for fluidizing it, one portion at a time, starting either at the top or the bottom of the filter. The second apparatus comprises a horizontal cylindrical elongated granular media filter having vertically spaced apart groups of jets on both sides, the jets of each group being in horizontal rows on two opposite sides whereby each successive horizontal row, including both rows on each horizontal plane through the filter, breaks up its respective portion of the plug, starting either at the bottom and working up or starting at the top and working down.

Abstract: This invention describes apparatus and process for filtering liquids by employing a vertical cylindrical container divided by an immovable non-porous plate into a separate top and bottom chamber with each chamber containing a bed of filter material. The liquid to be filtered is passed upwardly through the buoyant filter material of the top chamber and then passed in series through the filter material contained in the bottom chamber. Conduit means for passing the liquid from the top chamber to the bottom chamber is located internally of the cylindrical container; passing directly through the said immovable separating plate.

Abstract: An aerobic bacteria sewage treatment apparatus for treating waste water mixed with activated sludge by circulating the mixed liquor about a clarification compartment placed in a main treatment tank from which the clarification compartment withdraws water at a quiescent zone and further separates out and filters solid matter, finally delivering a well clarified effluent withdrawn from the top of the clarification compartment, the apparatus having an auxiliary digester compartment operative to periodically receive a proportion of the contents of the main tank, which contents are treated and allowed a time to settle out solids, whereupon the clear water from the auxiliary compartment is returned to the main treatment tank and the solids are left to accumulate for further treatment and later removal, the transfer of said proportion of the mixed liquor from the main tank being accomplished by overflow resulting from a purge cycle during which the clarification compartment is back-flushed into the main treatment ta

Abstract: Filtering solids from waste water liquids and cleaning, degreasing and restoring the filtering media through the use of cleaning compounds forced up through the filtering substances.

Abstract: A system for recovering chemically-treated water used to backwash and rinse a manganese oxide zeolite filter. The backwash and rinse waters are placed in a recovery basin, preferably with a coagulating agent, wherein the waters are agitated and then allowed to settle and thereby to separate from the water impurities removed from the filter. The backwash and rinse water so purified is then returned to the filter inlet for a normal service filtering pass through the filter. A number of filters are preferably serviced by each recovery basin, and automatic control means for the system are also disclosed.

Abstract: A fluid filter is disclosed wherein the in-flow passes through a plurality of beds in the filter in a generally horizontal direction. Means are provided to backwash the beds of the filter with the backwash fluid travelling through the beds in an upwardly vertical direction. Thus, the direction of flow of the in-flow is substantially normal to the direction of flow of the backwash fluid. Each of the beds is separately confined such that each bed may expand upwardly during backwash.

Abstract: The invention is concerned with an ion exchange treating system wherein two or more exchanger or absorber vessels are connected in series, each vessel being filled with ion exchange resin leaving sufficient freeboard to allow for expansion of the medium. Each vessel is provided with an expansion chamber positioned above it and includes a conventional distribution system. The flow of liquids passing through the system is countercurrent with respect to the medium to be treated and the medium which regenerates the ion exchanger or absorber. Generally, the liquid to be treated enters the first vessel at the bottom, exiting from the top, entering the second vessel at the top and exiting therefrom at the bottom.

Abstract: There is provided a pulseback technique for cleaning and renewing a panel bed contactor suitable for chemical or physical treatment of liquid and granular material. Free surfaces for entry of liquid are supported cooperatively by louvers. A pulseback technique rids the liquid entry surfaces of granular material spent by the treatment, including accumulated fine dirt particles if the treatment includes filtration to remove the dirt. The pulseback consists of a reverse transient flow across the panel bed of a intensity moderated so that the reverse pressure differential exceeds a critical minimum difference for not more than about 2000 milliseconds and attains a top value within about 600 milliseconds after the pressure differential surpasses the critical minimum difference.

Abstract: Apparatus and method for periodic backwashing and inoculating with anaerobic denitrifying bacteria a columnar filter bed in a waste water treatment system. A minor portion of backwash water containing a substantial quantity of denitrifying bacteria is retained for return to the filter bed media by gravity flow after completion of the backwash cycle. The apparatus and method have particular utility in an activated sludge sewage treatment system the effluent from which contains nitrates (converted from organic nitrogen and ammonia) and suspended solids which are removed in a filter bed comprising several discrete layers of filter sand of different particle sizes supported on coarse gravel.

Abstract: A tank containing a bed of particulate material, e.g. a sand filter bed or an ion exchange bed, has a bed-supporting bottom structure formed by upper and lower bottom plates rigidly connected with each other through a plurality of vertical sleeves opening into the spaces above and below the tank bottom structure. Openings in the wall of each sleeve connect the interior of the sleeve with the compartment formed between the bottom plates. A strainer unit is removably inserted in each sleeve through the lower end of the sleeve and passes liquid between the bed and the compartment between the bottom plates by way of the openings in the side wall of the sleeve.

Abstract: A gravity filtering equipment comprising a basin partitioned into a plurality of compartments each having a permeable bottom covered by a filtering bed and a device for flushing such filtering beds. This device comprises a bell adaptable fluid-tightly onto the upper edges of each compartment in turn and provided with a pump for sucking up filtered water, from a collecting chamber provided underneath the permeable bottom of each such compartment, through its filtering bed.

Abstract: A tank containing a bed of particulate material, e.g. a sand filter bed or an ion exchange bed, has a bed-supporting bottom structure formed by upper and lower bottom plates rigidly connected with each other through a plurality of vertical sleeves opening into the spaces above and below the tank bottom structure. Openings in the wall of each sleeve connect the interior of the sleeve with the compartment formed between the bottom plates. A strainer unit is removably inserted in each sleeve through the lower end of the sleeve and passes liquid between the bed and the compartment between the bottom plates by way of the openings in the side wall of the sleeve. An adjustable valve member accessible from below the tank bottom structure serves to control the flow of liquid through the strainer unit.

Abstract: This invention relates to aerobic biological processes for treating waste waters or sewage and an apparatus for carrying out the process.

Abstract: A method and apparatus reduces the amount of radioactive solids resulting from the filtration of particulate contaminants from liquid in a nuclear reactor plant. A filtration system includes a pre-filter comprising a sheet filter medium through which the reactor liquid passes to remove relatively large particulate contaminants for storage or disposal. The reactor liquid is then passed through a bed of granular filter medium to accumulate substantially all the previously non-filtered contaminants and thereby provide a clarified liquid suitable for reuse in the reactor. Backwash liquid is flowed through the granular filter bed to remove and entrain the accumulated contaminants into a slurry which is received by a reservoir where the slurry is maintained quiescently to settle the contaminants.

Abstract: An underdrain is provided in a water filtration system beneath a bed of filter media and comprises a plurality of elongate hollow underdrain units defining respective elongate substantially horizontal fluid passageways therein with the hollow underdrain units being arranged with the elongate fluid passageways thereof in fluid communication with each other and forming a network of fluid passageways beneath the bed of filter media. Each underdrain unit is provided with a plurality of nozzles in the upper wall thereof communicating with the interior of the hollow underdrain unit and with at least some of the nozzles in each underdrain unit cooperating with each other and being arranged in spaced groups. The cooperating nozzles in each group are so oriented as to direct streams of wash water issuing therefrom during backwashing into impingement with each other outside the filter underdrain unit for dispersing the streams of wash water and reducing the velocity thereof.

Abstract: A filtration and backwashing apparatus, for use with a filtration system of the type having a filter bed, passes fluids through the entire cross-sectional area of a filter media bed at an even and uniform rate. The apparatus includes two plenum chambers, one being formed between a slotted plate supporting the filter media and the top of the structural deck, the second or lower chamber being formed below the structural fluid-tight deck; nozzles communicating between the two plenum chambers; and means to introduce and pass fluid, either air or water into either the upper or lower plenum chamber.

Abstract: Process and apparatus for continuously obtaining separate outflows of pure water and sterile sludge when starting with various aqueous slurries containing organic or oxidizable contaminants (as exemplified by domestic sewage or industrial waste) and first treating the flowing mixture with sulfur dioxide and iron under conditions of closely controlled acidity and in the absence of oxygen. The invention provides a multiple-stage, closed, operating system, a primary segment of which is thus characterized by a self-contained, continuously recycling oxygen-free gaseous flow comprising sulfur dioxide gas which moves through an iron reaction bed concurrent with the contaminant stream.