Abstract: An apparatus and method for gas backwashing a granular media supported upon a lateral underdrain is disclosed. The lateral underdrain includes a plurality of dispersion apertures therethrough and at least one liquid return conduit extending to a discharge at a level below the dispersion apertures. The present invention provides for equal distribution of backwash gas across the entire lateral underdrain by directing backwash gas through the dispersion apertures into the granular media and directing liquid from the granular media through the liquid return conduit without obstructing backwash gas flow through said apertures from a gas pocket formed underneath said apertures.

Abstract: A method of preparing and cleaning a floating filter medium for a biological cleaning apparatus includes the steps of forming a filter layer by placing in a treating tank a granular floating filter medium having a specific gravity of about 0.3 or less and a particle size of 1 to 15 mm. Wastewater enters the tank and flows through the filter layer. Excess sludge is separated and removed from the filter medium by discharging an amount of water from the treating tank, from below the filtered layer, equivalent to 0.5 to 1.5 times the filling amount of the filter medium in a time period of between 5 to 90 seconds.

Abstract: New methods are disclosed for improving the cleansing the plurality of seriate filter beds in automatic backwash filtering systems, equipped with a traveling backwash shoe, in which the beds are backwashed one at a time with backwash liquid from an effluent channel common to seriate effluent ports of the plurality of filter beds by pumping the backwash liquid seriatim through separate effluent ports of individual filter beds and then flowing filtered effluent from each bed through its effluent port into the effluent channel, repeating such steps of backwashing and flowing filtered effluent on individual filter beds until all the filter beds in the system have been backwashed, wherein, simultaneously with the backwashing of such active bed, the bed forward in the direction of travel of the backwash shoe is subjected to a prewash with chemical treatment liquid by pumping such liquid upwardly in such forward bed through its effluent port. Apparatus for carrying out the improved methods is also disclosed.

Abstract: An apparatus and method for gas backwashing a granular media supported upon a lateral underdrain is disclosed. The lateral underdrain includes a plurality of dispersion apertures therethrough and at least one liquid return conduit extending to a discharge at a level below the dispersion apertures. The present invention provides for equal distribution of backwash gas across the entire lateral underdrain by directing backwash gas through the dispersion apertures into the granular media and directing liquid from the granular media through the liquid return conduit without obstructing backwash gas flow through said apertures from a gas pocket formed underneath said apertures.

Abstract: A gas is blown into a filter (1) having a granular filter bed such that the gas flows into the bed along at least one elongate free edge disposed in the bed.

Abstract: A rapid gravity downflow filtration system applicable to a bank of several filters in which filtered water for backwashing is stored at a relatively high level in a common washwater storage compartment serving all filters and in which the filtered water for backwashing is delivered to it's storage by gravity using the surplus operating head available at the beginning of the filter operating cycle for the purpose thereby entirely eliminating the necessity for powered motivation of backwash water flow during backwashing, or, in alternative filter systems in which the backwash water flow is motivated by displacement with compressed air, reducing the power requirement.

Abstract: A filter for removal of biochemical oxygen demand and suspended solids utilizing multi-layer filtration media. The filter media includes plastic particles, sand, and garnet and is operated under an automatic control condition. Fine filtering is accomplished by a sludge cake which develops at the upstream face of the filter media. For cleaning the filtration media, deposited sludge is removed from the filter bed by backwashing in a short time period at a high strength backwash flow rate.

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

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

Abstract: A process for the treatment of water using a granular bed (3) of granular support materials of a volumic mass less than that of the water to be treated. According to this process, each washing cycle comprises interrupting the withdrawal of treated water and stopping the feed of water to be treated in such a manner that the granular bed (3) floats in a given volume VL of water, admitting cleansing air into the reactor for assuring agitation of the floating bed, interrupting the admission of air in order to permit a separation of the granular materials and sediment by their difference in volumic mass, with decantation of said sediment and flotation of said materials, and evacuating the sediments at the base of the reactor as well as the water contained therein for evacuating the granular bed (3).

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

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

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

Abstract: A process and apparatus for the filtration of a creosote process stream laden with insoluble materials is provided. The apparatus comprises a filtration apparatus of a shell-and-tube configuration having filter material within for the separation of the xylene from the insolubles; the apparatus is comprised within a creosote filtration system which further includes a means for periodically backflushing the filtration system to reduce clogging of the filter material. The process and apparatus herein also finds use for filtration of other materials, including tars, pitches, and wastewaters.

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

Abstract: An improved apparatus and process for the operation of a down-flow granular medium bed filter is disclosed. A splash plate for dissipating the force of influent liquid is rotatably connected to support means, allowing the plate to rotate from a position parallel to the bed surface to a position perpendicular to the bed surface upon the liquid above the bed rising to a selected first level. The splash plate is maintained in the perpendicular position for the remainder of the filtration cycle, the backwash cycle and any chemical cleaning cycle, allowing unobstructed operation of the filter bed. The splash plate returns to the original position at the start of another filtration cycle.

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

Abstract: An improved method for maintaining a granular medium filter in a clean, operable condition is disclosed. The time interval required for the level of liquid above the filter bed to drain from a backwash outlet level to the upper bed surface level following a backwash cycle is monitored. Upon this measured draindown time exceeding a predetermined interval of time, a chemical cleaning cycle is initiated for the granular medium bed filter.

Abstract: The invention is directed to a process for separating solid particles and/or liquid from a liquid suspension and/or purifying or leaching solid particles in a column containing a compacted bed, which comprises supplying a liquid suspension to said column while withdrawing liquid phase therefrom through a filter construction, disintegrating the washed compacted bed and removing the product of this disintegration, the washfront in the compacted bed being moved between two extreme limits in the compacted bed and to a wash column for use in this process.

Abstract: A process and apparatus for protecting a media bed filter with underlying support screen from solids contained in a liquid, such as filtrate from the filter, used to regenerate or backwash the media bed filter. Filtrate enters a first collection chamber containing a screen assembly covering one outlet, the chamber also containing a second outlet. Filtrate traverses the screen assembly and is transferred to a second collection chamber with addition of a predetermined amount of bactericide to prevent solids growth therein. Upon bactericide-treated filtrate reaching a predetermined level within the second chamber, filtrate in the first chamber bypasses the screen assembly and flows out the second output to further biological treatment or use. Bactericide-treated filtrate from the second collection chamber is used to regenerate or backwash the media bed filter with addition of optional surfactant to assist in cleaning the filter media and underlying support screen.

Abstract: A method of cleaning a filter having a plurality of elastic, porous hollow fibers with lumens within a shell or housing and in which filtration is carried out by applying a liquid suspension feedstock to the outer surface of the fibers whereby a portion of feedstock passes through the walls of the fiber to be drawn from the fiber lumens as a filtrate or permeate, and a portion of the solids in the feedstock are retained on or in the pores of the fibers, with the non-retained solids being removed from the shell or housing with the remainder of the feedstock, said method entailing introducing a pressurized gas into the fiber lumens which passes through the walls of the fibers to dislodge the retained solids, the gas being applied at a pressure which is sufficient to overcome the effect of the surface tension of the continuous phase of the feedstock within the pores of the membrane.

Abstract: A process for removing sorbed lubricating oil additives from siliceous filter material is provided. The process comprises forming a slurry of the additive-laden siliceous filter material and an aromatic solvent. Water is added to the slurry prior to separating the siliceous filter material from the slurry. The recovered filter material is substantially additive-free. The lubricating oil additives may be optionally recovered from the aromatic solvent by appropriate means such as distillation.

Abstract: A process for regenerating media filters used to filter geothermal brine, especially flashed and clarified, silica-rich brine, comprises flowing steam through the filter in a backflush direction at a rate and for a time duration agitating the filter media and filtered-out material. The process includes, preferably after the steam flow is stopped, flowing brine, for example, filtered brine, through the filter in the backwash direction to flush out the material loosened and broken up by the steam scour and restratify the media bed components, and may include partially draining the filters prior to the steam scour. Preferably, the steam used for the steam scour is low pressure steam obtained from low pressure flashing of the brine being filtered. Steam flow rates are preferably between about 2 and about 10 SCFM per square foot of filter cross-sectional area in the region of the filter media; steam flow rate is preferably about 5 minutes after any steam quenching has ceased.

Abstract: An improved method of cleansing a filter bed is herein provided utilizing a backwash pump (12) having an inlet line (14) and an outlet line (16). The improved method and system includes two cycle operations. Initially, the filter bed is backwashed to remove contaminants from the filter bed with the backwash pump (12) drawing liquid from an effluent channel (26). A portion of the liquid passing on backwash pump outlet line (26) is passed through a bypass adjustment valve (34) for egress on an outlet line (38) for recirculation to the effluent channel (26). The second stage of the cleansing operation is through a purging cycle where the filter bed is purged subsequent to the backwashing operation for removal of further contaminants from the filter bed.

Abstract: Dirty diphenylamine solution is pumped from a reservoir (12) first through a cyclone separator (28) and then through a media filter (50) and back to the reservoir (12). A first large flow rate pump (30) is used to cause flow through the cyclone separator (28). A second lower capacity pump (52) pumps a portion of the solution that is delivered out through the cyclone separator (28) into the inlet (48) of the media filter (50). The remaining portion of the outflow from the cyclone separator (28) is directly returned to the reservoir (12). Fresh water via a conduit (78) and then compressed air via a conduit (82) are flushed through the filter (50), to wash chemical out from the filter (50) and carry it into the reservoir (12). Then, fresh water is directed back in the reverse direction through filter (50), to backwash the filter (50). The water used for backwashing is dumped via conduit (90).

Abstract: A system is provided for removing iron and/or other chemically reducing substances from potable water having a pH between 5 and 9. The system includes a tank for receiving the water which tank contains a bed of activated carbon. The untreated water is aerated prior to its communication with the activated carbon. All of the aerated water is allowed to flow through the bed and the activated carbon provides a catalytic action, whereby substantially all of the oxidation occurs throughout the bed of activated carbon and the use of chamical oxidizing agents is obviated. The tank provides a reaction site for oxidation in the catalyst, precipitation of the oxidized ions, and retention by filtration of the precipitated particles.

Abstract: A process for heating and softening of hard water by direct heat exchange with steam. The steam is directly sparged into the hard water within a reaction zone and condensed in the water under a pressure sufficient to prevent boiling at the reaction zone temperature. The heated water is then withdrawn from the reaction zone without substantial vaporization of water and filtered to remove scale precipitates resulting from the heating step. At least a portion of the softened water may be heated to generate wet steam which is then recirculated to the reaction zone and sparged into the hard water therein.

Abstract: A filtration process and apparatus for the removal of solids from liquids is provided having a filter bed vertically disposed in a chamber which has a solids-containing liquid passed horizontally therethrough. The filter bed is regenerated after becoming loaded with solids. During filtering the liquid is divided into at least two partial streams, and each partial stream is conducted through a respective filter bed arranged in a chamber, which is comprised of reticulated particles of polyurethane. After the particles have been completely loaded with the solids, the liquid feed to and the liquid discharge from the respective chamber are interrupted. The solids adhereing to the particles are then transferred by agitation and/or gas treatment into a liquid volume remaining in the chamber, and the liquid volume is discharged together with the solids. The process is especially adaptable to be utilized in wastewater treatment, or for the removal of solids from scrubbing media.

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 method of and a system for removing miniuscule solid particles from liquid wherein the liquid to be processed is supplied to one end of at least one filter element which may be a porous tube filter open at opposite ends and formed with a multiplicity of tiny openings in its wall having a first surface and a second surface. The liquid flows along the first surface and a portion thereof is passed through the tiny openings from the first surface side to the second surface side because of the latter being under lower pressure than the former, to be drawn off as filtrate. The rest of the liquid or a concentrated liquid portion flows out of the other end of the filter element. The flow velocity F of the liquid flowing along the first surface and/or the flow velocity f of the filtrate through the tiny openings is controlled such that the ratio F/f can be kept at a predetermined value.

Abstract: The method of treating human waste in a toilet system for disposal of the waste and recovery of the flushing liquid comprising reducing the solid matter in the effluent by hydraulic attrition in substantially one and a half liters of water containing an effective amount of decontaminant to a particle size which ranges from 1/8 inch to 1/2 micron and in which the solid matter in excess of 1/64 of an inch does not exceed more than 18% of the total solid matter, filtering the solid matter from the water and employing the filtered water following each flushing operation for a succeeding flushing of the system.

Abstract: A process for the purification of salt brine having magnesium and calcium hardness includes the steps of treating a saturated salt brine containing magnesium and calcium ions with an alkali metal carbonate and an alkali metal hydroxide in a preselected sequence and in amounts in excess of stoichiometric proportions to form firm, readily settleable, filterable floc precipitate particles of insoluble compounds of magnesium and calcium, suspended in the treated brine and passing the resultant suspension to a filtering unit to separate and remove the floc precipitate and to provide a purified salt brine.

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 method is described in which two or more granular filter media are used in combination in such a manner that the filter bed is backwashed using air and water simultaneously. The media size gradation and density are selected so that, although the media may be mixed during backwash, the media are separated into layers according to their density and/or size following termination of the simultaneous air-water wash and prior to returning the filter to the filtration mode. The simultaneous air-water wash step can be carried out without media loss by use of an appropriate media retaining procedure.

Abstract: A process and apparatus for separating liquids of different specific gravities, and more particularly for separating oil from water. The oil-contaminated water is pumped by a low emulsifying pump from a storage site to an oil gravity separator where a substantial portion of the oil is separated by gravity from the water. The water is then delivered from the gravity separator to a regenerative filter composed of a plurality of layers of granular media which serve to remove foreign materials and the remaining oil from the water. The clarified water can then be discharged to a discharge site. The oil-separator vessel includes an upper oil collection zone, and a capacitance-type sensor is responsive to the level of oil in the collection zone and operates, when the oil reaches a pre-set maximum level, to close a valve to prevent water flow to the regenerative filter, while opening a drain valve to permit the oil to be discharged from the separator vessel by the pump to an oil recovery tank.

Abstract: A single enclosed chamber includes a lower destabilizing area, a central filtering and coalescence area containing coalescence material, and an upper flotation and separation area. Emulsion is introduced into the lower destabilizing area and is destabilized therein. The emulsion is then passed upwardly into the central filtering and coalescence area. The dispersed phase of the emulsion is attracted to the coalescence material in the form of droplets, and as the emulsion continues to pass upwardly therethrough the droplets grow in size. During passage of the emulsion through the filtering and coalescence material, matter in suspension is filtered from the emulsion. Within the flotation and separation area is located a separation device including a lower convergent portion and an upper divergent portion.

Abstract: A filter apparatus having multiple filter medias for use in environmental control, food processing and other industrial applications, is provided with movable filter media separators that maintain media separation while permitting bed expansion during a backwash cleaning operation. The filter bed can comprise, for example, a lower sand layer and an upper anthracite layer, as well as a free board zone above the anthracite layer. Said layers are separated by a movable filter media separator. A screen is provided at the filter inlet to prevent loss of filter media during the backwash cleaning operation.

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.