Abstract: Conventional biological processes for treating wastewater include the so-called activated sludge process which is continuous and the sequencing batch reaction (SBR) activated sludge process. The first process requires the use of dedicated, relatively expensive external clarifiers, and the second process is inefficient in terms of treatment volume. A modified sequencing batch reactor process and system enable the efficient, continuous treatment and discharge of wastewater, combing the advantages of the SBR and activated sludge processes. In the present case, wastewater is initially fed in a first direction through a plurality of contiguous cells, the wastewater is subjected at all times to biological treatment in a plurality of such cells and settled in at least one of the cells immediately prior to discharge from the system.

Abstract: A wastewater treatment system and method is disclosed, including a circular aeration basin and a contiguous annular clarifier channel. Rotational flow of an aerated mixture of untreated wastewater and return sludge is induced in the aeration basin at its periphery with relatively less turbulent flow at the center.A clarifier inlet is fluidly connected to the aeration basin through openings provided in the aeration basin wall, the clarifier inlet including means to dissipate turbulence.A sludge removal manifold extends within the clarifier having valve-controlled suction arms. The spaced suction arms provide for precise control of sludge blanket depth and sludge age independent of rate of sludge return to the basin.Process sludge withdrawn from the clarifier is mixed with raw wastewater and returned to the aeration basin.The relatively less-turbulent flow in the central area of the basin allows process sludge to accumulate in said central area.

Abstract: Dual purpose apparatus and process for increasing the efficiency of absorption of oxygen by a biodegradable waste in a continuous operation in a waste collection station and for removing the oxygen enriched waste from the collection station by separately introducing waste and oxygen, which may be air, into a collector under a highly agitated state, and agitating the air and waste under pressure in a collector by a partially recessed vortex type impeller as back pressure is provided to the collector either by a nozzle means or an outlet means. The collector is mis-matched relative to the impeller to increase the retention and mixing time of the air and waste in the collector.

Abstract: Apparatus is disclosed for improvement of water quality in a pond or similar body of water. A main conduit is located below the water surface and extending generally parallel to the shoreline. A plurality of distribution conduits are attached at intervals to the main conduit and operated sequentially so that water pumped through the system causes circulation of water in the pond. Each distribution conduit will preferably incorporate an aspirator to aerate the pumped water. The pumped water will also normally contain a mixture of microorganisms, enzymes and nutrients which are discharged into the body of water to clarify the body of water of contaminants and to maintain the water quality thereafter. Also disclosed is a method of improving water quality using the apparatus and the mixture. The invention provides for thorough, efficient and rapid decontamination of ponds and elimination of stagnant areas, as well as for maintaining the ponds in clean and healthy conditions.

Abstract: A system for in-situ bioremediation includes a well extending into a saturated zone. The well includes a casing having two permeable sections in the saturated zone. Groundwater may be recirculated through the well and the saturated zone between the two permeable sections. Nutrients, such as oxygen and methane, may be added to the groundwater as it flows in the well. A venturi transfer device may be used to supply the nutrients.

Abstract: A complete mix activated sludge basin is operated as a Sequence Continuous Reactor by cyclically aerating the mixed liquor to form an aerobic cycle at selected high dissolved oxygen levels, during which nitrification takes place, and cyclically mixing the liquor without aerating to form anoxic cycles at selected low dissolved oxygen levels, during which denitrification takes place. Field adjustments can be made by the operator in the dissolved oxygen levels and in the duration of the aerobic and anoxic cycles, whereby ammonia removal, nitrification, and denitrification can continue to be done efficiently during both summer and winter temperature conditions, during conditions varying from warm to cold inlet wastewater temperatures, during extreme variations in food supply, and during pronounced variations in biomass concentration and activity.

Abstract: Raw sewage ("black water" from toilets), wastewater from showers, sinks, kitchen facilities ("grey water") and oily water from the bilge of a host vessel ("oily water"), in combination, unexpectedly provide the essential nutrients for a live mass of mixed microorganisms which are peculiarly well-adapted to ingest the nutrients. To facilitate availability of oxygen to the microorganisms so as to provide growth of the microorganisms, and also, to allow them destroy to themselves, excess oxygen is discharged, in a combination of microbubbles and macrobubbles, into a membrane bioreactor ("MBR"). The mixture of bubbles is preferably generated with coarse (>2 mm) and fine (<20 .mu.m) bubble diffusers. An auxiliary stream, whether alone, or a recirculating stream into which air is drawn, may provide the coarse bubbles. The air is entrained, in a jet aerator or eductor, in a recirculating loop of activated sludge taken from the MBR.

Abstract: A system and method for the decontamination of contaminated ground is described. Contaminated soil gas containing the contaminant is removed from the contaminated ground. Contaminants are separated from the contaminated gas and treated to lessen an environmental hazard of the contaminant. Contaminants are preferably treated by non-thermal oxidation. Residual soil gas, including any oxygen, unoxidized contaminants, and oxidation products (water vapor and carbon dioxide) are returned to the ground, where unoxidized contaminants are subject to oxidation by soil microorganisms. The returned residual soil gas is recirculated through the decontamination system.

Abstract: A wastewater orbital treatment system includes an elongated racetrack-like tank containing a central partition wall. A surface aerator is mounted adjacent to at least one end of the partition wall to both aerate and propel the mixed liquor including biomass around the orbital tank. An aerobic zone for BOD and ammonia oxidation is provided in an upper layer of the moving volume of mixed liquor and an anoxic zone for reduction of NO.sub.x from the aerobic zone, by anoxic respiration by the biomass, is provided in a lower layer of the moving volume of mixed liquor. An imperforate horizontal baffle is provided under the surface aerator so as to prevent dissolved oxygen in the aerobic zone from entering the anoxic zone. The NO.sub.x from the aerobic zone is introduced through a free interface of the two vertically displaced zones downstream of the baffle.

Abstract: The method and apparatus of the invention are directed to the removal of pollutants from ponds, lagoons, streams, and similar waters. Floating apparatus is designed to house, nurture, and support colonies of fixed-film bacteria and/or more complex microorganisms specifically appropriate for consuming the particular contaminants present in the pond being treated. The colonies of microorganisms are first grown as bio-films in a relatively large bio-chamber that is filled with bio-suspension forms. Then, only after the colonies become large and stable, is pond water circulated through the bio-chamber, such circulation being gentle and without agitation. The apparatus also includes (a) a pond-water intake; (b) a water mixing chamber; and (c) an equipment pod which houses water and air pumps, a water heater, a weather station, water-condition monitoring devices, and a microprocessor.

Abstract: Conventional biological processes for treating wastewater include the so-called activated sludge process which is continuous and the sequencing batch reactor (SBR) activated sludge process. The first process requires the use of dedicated, relatively expensive external clarifiers, and the second process is inefficient in terms of treatment volume. A modified sequencing batch reactor process and system enable the efficient, continuous treatment of wastewater, combining the advantages of the SBR and activated sludge processes. Wastewater is treated in three contiguous treatment sections, each of which includes a plurality of contiguous cells. In a first series of operations, the flow direction is from the first to the third sections, and in a second series of operations the flow is reversed. In each series of operations, the first step is to aerobically treat the wastewater, and then allow the sludge to settle before discharging the treated wastewater from the system.

Abstract: A transportable apparatus for biological treatment of a slurry of contaminated materials, including a series of square reactor cells having substantially parabolic lower portions, set at the same elevation and communicating in series. Gas diffusers are placed in each cell for aerating and mixing the slurry, and an airlift slurry transport system is employed for recirculating the slurry. The apparatus also has applicability to the treatment of water and waste water.

Abstract: The present invention relates to a system and method for biologically removing nitrogen from wastewater. Both the system and method entails forming a mixed liquor and transferring the mixed liquor to a series of nitrogen removal stages. Each nitrogen removal stage includes both anoxic and aerobic treatment zones. Mixed liquor is recycled back and forth between the anoxic and aerobic treatment zone of each stage. Because of this basic flow scheme, the process gives rise to a high reactor rate and highly efficient nitrogen removal process.

Abstract: A method and apparatus for the continuous degradation of hazardous paint and organic solvent wastes. The apparatus includes a high performance fixed film bioreactor system into which is fed waters contaminated with paints or solvents from industrial operations and which utilizes the characteristic of either anaerobic or aerobic microorganisms growing on a fixed film for the degradation of these solvents and purification of contaminated waters. The bioreactor incorporates novel internal flow features which result in highly effective destruction of organic wastes in aqueous streams.

Abstract: A sequencing batch reactor is controlled to provide an effective, efficient treatment of raw waste water. Controls include regular withdrawal of mixed liquor during each cycle of operation. The withdrawal is volumetrically controlled to provide a sludge retention time of 5 to 10 days in the system. This produces a carbon and nitrogen oxydizing bacterial culture with good setting properties. Hydraulic loads in the system are controlled according to liquid levels, while the bacterial processes are controlled by timed sequences. A storm control procedure monitors the influent rate and shortens the cycle times according to the magnitude rate, to increase the system capacity. The system also includes a novel effluent withdrawal system, with a check valve controlled intake about midway up the reactor. This is trouble-free, with the check valve preventing sludge entry into the effluent withdrawal and maintaining prime on the effluent withdrawal pump.

Abstract: A secondary sewage treatment system is provided with vertically-aligned foam collecting, turbulent, mixing, settling, and sludge collecting zones. A grating defines the boundary between the turbulent and mixing zones. Beneath the grating, a buoyant media, such as hollow plastic spheres, are contained and occupy substantially all of the mixing zone. Air diffusers including elongated draft tubes extend from the turbulent zone down through the mixing zone for introduction of air to aerate waste water liquor and to cause the aerated liquor to recirculate up into the turbulent zone, thereby creating a circulation of waste water liquor from the turbulent zone, down through the mixing zone and around the buoyant media, and up through the draft tubes to the turbulent zone.

Abstract: A secondary sewage treatment system is provided with vertically-aligned foam collecting, turbulent, mixing, settling, and sludge collecting zones. A grating defines the boundary between the turbulent and mixing zones. Beneath the grating, a bouyant media, such as hollow plastic spheres, are contained and occupy substantially all of the mixing zone. Air diffusers including elongated draft tubes extend from the turbulent zone down through the mixing zone for introduction of air to aerate waste water liquor and to cause the aerated liquor to recirculate up into the turbulent zone, thereby creating a circulation of waste water liquor from the turbulent zone, down through the mixing zone and around the bouyant media, and up through the draft tubes to the turbulent zone.

Abstract: The fluid-bed reactor for biological effluent treatment, using carrier particles for microorganisms, consists of a tank with a retention system for the carrier particles, gas supply units and a jet ejector arranged along the tank for the particle recycle. The propulsion nozzle of the jet ejector is fed with the effluent stream which is to be treated.

Abstract: The present invention relates to a method and an apparatus for biological purification of wastewater with no excess activated sludge by subjecting a machanically and/or chemically pretreated wastewater to the conditions of total endogenous respiration at aeration with one or more surface turbine type aerators of 5.10.sup.-2 to 12.10.sup.0.2 kW/m.sup.3 of wastewater, at a microorganism to food ratio of 20 to 100. The height of the liquid level in the basin is at least 5 m. There is provided a high-grade effluent at low capital and operational investment.

Abstract: An aquarium filter assembly (10) which comprises a filter body (12) made of an open celled foam material which supports a culture of aerobic bacteria which removes toxic ammonia from aquarium water in which it is immersed. The filter body (12) substantially defines a closed cavity (14) and a passageway (30) extends through the open celled foam material into cavity (14) for receipt therewithin of an aerator lift tube (32) of a cross sectional dimension substantially less than that of the cavity (14) leaving open space in the cavity (14) and to draw aquarium water therefrom to cause aquarium water to freely flow into the open space of the cavity substantially uniform through the entire amount of open celled foam material of the filter body (12). The aquarium filter assembly also includes a means for mounting (43) the filter body (12) within the aquarium but spaced from interior surfaces thereof to permit unobstructed flow through substantially the entire filter body (12).

Abstract: Contaminated water is caused to flow up through a chamber while aerated to produce air bubbles of a size mainly in the range of 0.03 mm to 1 mm by means of air diffusors disposed at the bottom of the chamber. Organic and inorganic impurities in the water is, by a combination of water flow, flotation and physical adsorption caused by the air bubbles, brought to the surface of the water in the chamber, where a foam containing dissolved impurities is formed and instantly removed from the chamber while a mixture of water particles and microscopic air bubbles is allowed to flow over a partition wall into an adjacent basin having a considerably larger volume than that of the chamber. In the basin a flotation process will take place causing a slurry to form on the surface of the water in the basin, which is removed, preferably at the end of the basin opposite the chamber.

Abstract: An improved method and apparatus for treating liquor containing biodegradable wastes wherein the liquor is first delivered to a quiescent primary settling zone and then to an aeration zone. The aerated liquor is delivered downwardly through a column of submerged fixed media having a high surface area to volume ratio so that aerobic microorganisms can grow on their surface. The liquor is recirculated through the aeration zone and fixed media, and is withdrawn from the unit after treatment. A portion of the aerated liquor from the top of the fixed media is recycled back into the primary settling zone to denitrify the nitrate rich aerated liquor by deoxygenating the dissolved nitrates and to equalize the BOD load in the secondary aerobic treatment zone.

Abstract: In a system for biodegrading oxidizable organic waste in a bioreactor in combination with a membrane ultrafiltration unit used to separate a high quality permeate from activated sludge which is returned to the bioreactor from the membrane unit as a recycle stream, it has been found that an in-line fine bubble diffuser or "micronizer" takes advantage of the kinetic energy in the recycle stream to aerate the biomass with surprising efficiency. The micronizer is positioned external to the biomass in the bioreactor; the discharge from the micronizer provides a microaerated tail-jet of the recycle stream which has been infused with a mass of air bubbles from 1-1000 .mu.m in diameter. The velocity of the compressed air flowed into the micronizer keeps its pores from clogging with sludge. The energy of the recycle stream without the air is insufficient to provide the requisite motive force for adequate oxygen transfer and to establish a predetermined recirculation pattern.

Abstract: There is described a process for the simultaneous chemical and biological elimination of solid and liquid waste and apparatus for performing this process in the form of a loop reactor corresponding to FIG. 1 in conjunction with a specially designed nozzle which ensures an intimate mixing of substrate with air and the spraying-in of oxidizing agents while permitting only a short contact time between the oxidizing agents and the substrate.

Abstract: The invention relates to an apparatus and process useful for the biological transformation of waste materials into ecologically desirable materials. A meta system reactor is disclosed comprising three primary zones which are cyclically and dynamically connected by a circulating fluid. In the process of the invention, each of a bioreactor zone, solids ecoreactor zone and georeactor zone further comprise secondary subsystems and are cyclically connected by a series of recycle flows and organism movements to bioconvert the contained materials. The converted materials produced can be desirable and ecologically beneficial end products comprising gases such as nitrogen, oxygen, carbon dioxide, and water vapor; a biologically active and highly beneficial humus material; and clean water which may be passed through a final wetlands polishing and biomonitoring system before discharge into a natural receiving water.

Abstract: The sewage lagoon system has a first pond containing mechanically and biologically degrading dissolved and undissolved organic and anorganic pollutant matter, without a recirculation of the forming activated sludge. The first pond is connected to a nitrification lagoon. It contains vertical contact beds for gathering nitrobacteria, which are horizontally flown through. The flow and the introduction of air in the nitrification lagoon are effected by air-water pumps generating a directed flow and provide the transversal flow through the contact beds. The circulation rate in the nitrification lagoon is at least 10 times the throughflow rate.

Abstract: In order to improve the efficiency of biological reactors for water cleaning with fluid filtration, the activated sludge descending from the space of the fluid filter is simultaneously forcibly sucked-off into the activating space due to a stream of the activating mixture in the close neighborhood of the stream of the returning activated sludge at the place of its entrance into the activating space. Pumping can be applied for the sucking-off function.

Abstract: A secondary sewage treatment system is provided with vertically-aligned foam collecting, turbulent, mixing, settling, and sludge collecting zones. A grating defines the boundary between the turbulent and mixing zones. Beneath the grating, a bouyant media, such as hollow plastic spheres, are contained and occupy substantially all of the mixing zone. Air diffusers including elongated draft tubes extend from the turbulent zone down through the mixing zone for introduction of air to aerate waste water liquor and to cause the aerated liquor to recirculate up into the turbulent zone, thereby creating a circulation of waste water liquor from the turbulent zone, down through the mixing zone and around the bouyant media, and up through the draft tubes to the turbulent zone.

Abstract: A process strategy for the treatment of wastewater in a sequencing batch reactor wherein wastewater in quantities above a preselected minimum amount is proportionally aerated so as to reduce energy usage and operating costs.

Abstract: In an orbal wastewater treatment process including a plurality of concentric, annular basins or channels having surface aeration means, wastewater and recycled activated sludge are mixed in a first channel by a combination of the surface aeration means and introducing an oxygen-containing gas such as air into the lower portion of the zone under conditions which produce a complete mix reaction and sufficient oxygen is supplied to meet the biological oxygen demands of the mixed liquor. The gas is introduced, preferably by a plurality of fine bubble membrane diffusers, in the form of fine bubbles having a diameter of less than about 4 mm. The mixed liquor is sequentially oxidized in second and third channels by a combination of surface aeration means and introducing an oxygen-containing gas into the lower portions of the channels, preferably by fine bubble membrane diffusers.

Abstract: The present invention relates to a reactor for biological purification of pollutant-containing water in a closed vessel by means of loop operation. This vessel contains, disposed vertically and concentrically with respect to its jacket and to each other, an insertable pipe that is open at both ends, into which a nozzle projects for the purpose of supplying the water-gas-biomass mixture to be purified, and a guide pipe that is open at both ends and that forms an inner annulus with the internal insertable pipe and an outer annulus with the reactor jacket. This guide pipe projects above and below the ends of the insertable pipe. A deflector plate is mounted below the insertable pipe but inside the guide pipe, so that part of the biomass-water mixture is deflected back into the inner annulus. A conically shaped sedimentation chamber is disposed in the lower part of the reactor.

Abstract: A thickener well is provided in one end of a digester orbital ditch having a pair of channels and an elongated center partition spaced from a pair of ditch endwalls, the overall ditch forming a basin for digestion of wasted sludge. A curved endwall of the ditch provides a common curved top outer peripheral wall of the thickener well. The remainder of the well has a cylindrical configuration integral with the orbital ditch bottom and extending downwardly therefrom to a position below the horizontal plane of the ditch bottom. A sludge raking structure is positioned at the bottom of the well for periodically raking settled sludge into a sludge outlet at the bottom of the well. A surface aerator is provided between and spaced from the other ditch endwall and a juxtaposed end of the partition or other aeration apparatus mounted in a channel(s) to aerate and propel a liquid-solids sludge mixture wasted from a secondary treatment apparatus and fed into the orbital ditch.

Abstract: A flushing water-circulation type flush system to purify living water or sewage into clean water. Water discharged from a toilet is directed successively to a filter bed unit having filter material therein, to an aeration unit, to a settling unit where solids are settled out, to a pH regulation unit containing an adsorber column having activated carbon therein, the pH unit also containing a source of calcium carbonate, with the adsorber extending therethrough. Outflow from the adsorber is passed through a sterilizer unit to a flushing water unit which serves as a source for supplying flushing water to a water reservoir for the toilet.

Abstract: For use in an activated sludge process, dual-baffle aerators for both vertically mounted surface aerators and static mixer-aerators are disclosed. These devices substantially prevent back-mixing of freshly aerated liquor into aerator intakes and provide directional propulsion. By connecting two or more such devices to form a barrier across the channel of an oxidation ditch, homogeneous aeration is provided to the mixed liquor. Barriered pump/aerator assemblies utilizing directional mix jet aerators (eddy jet) are also described. These devices can also be combined with dual-baffle aerators to furnish both propulsion and a selected degree of homogeneous aeration in a barrier oxidation ditch. An adjustably apertured barriered pump assembly is additionally disclosed for providing a selected balance between homogeneous aeration and/or mixing and heterogeneous aeration and/or mixing.

Abstract: Apparatus for increasing the efficiency of absorption of oxygen by biodegradable waste and particle break-up thereof, by introducing waste and gas, which may be air, into a collector under a highly agitated state, and agitating the air and waste under pressure in the collector by the impeller of a vortex type centrifugal pump as back pressure is provided to the collector. The collector is mis-matched relative to the impeller to increase the retention and mixing time of the air and waste in the collector.

Abstract: A dispersion of air or oxygen in liquid sewage and/or or sludge is admitted tangentially into the lower portion of an upright vessel wherein the dispersion rises and is compelled to flow through eccentric flow restricting passages in several superimposed horizontal partitions so that the dispersion is repeatedly induced to form a turbulent helical flow. The rising dispersion flows around a tube which returns a portion of the dispersion into the lower part of the vessel and causes the remaining portion to overflow into a receptacle having an outlet at a level below the open top of the tube. The dispersion which descends in the tube is readmitted tangentially into one or more chambers which are separated from each other by the partitions in the vessel and communicate with each other by way of the respective flow restricting passages.

Abstract: This invention relates to a process and reactor system suitable for biological treatment of wastewaters or for other applications wherein effective and intimate contact between biological populations attached to a fixed surface and liquid born chemicals and gaseous atmospheres is required. The reactor includes a sealed housing generally having a plurality of independent-vertical chambers, each open at the top and bottom and each filled with high surface-area packing and disposed annularly around a central-vertical chamber. The central vertical chamber is also open at the top and bottom, but free of packing. The bottom of the central chamber is in communication with the bottom of each of the independent-annular columns by means of a bottom-freeboard chamber. The top of the central-vertical chamber is also in communication with the top of each independent-vertical chamber by means of a top-freeboard chamber created by setting the liquid level in the reactor at a position above the top of all vertical chambers.

Abstract: A reactor for waste water including a vessel 10 having two elongated outer channels 26, 28 sandwiching an elongated inner channel 30 with all the channels 26, 28 and 30 being connected to each other at both opposed ends thereof, a gate 64 at one of the ends 18 and movable between a first position isolating the channel 26 from the channels 28 and 30 and a second position isolating the channel 28 from the channels 26 and 30, rotors 32, 34 for each of the channels 26, 28 for aerating waste water in the vessel 10 and for causing the waste water to flow in the corresponding channels 26, 28 as well as the inner channel 30, and a pair of effluent outlets 98, 100, located at the end 18 and spaced to be on opposite sides of the gate 64, each selectively operable to withdraw effluent from the the outer channels 26, 28 on the associated side of the gate 64.

Abstract: A continuous fermentation device for receiving a suspension culture of cells includes a fermentation vessel having inlet means to deliver suspension culture medium; baffle means defining, in combination with interior walls of said vessel, a downcomer and a riser; pump means for forcing a suspension culture to circulate in the riser and downcomer; a portion of said baffle means further defining a static settling zone disposed within said vessel, wherein said zone is surrounded by at least one of said riser and said downcomer, said zone having a bottom opening communicating with at least one of said riser and downcomer, and a top opening connected to outlet means to draw off culture supernatant, and wherein said zone provides for cells to settle out in its bottom so as to result in a cell concentration lower in the supernatant than in the suspension. The device may be employed in a method for the suspension culture of cells by culturing cells therein.

Abstract: A jet aerator header assembly is provided for the deep oxygen contact duct of a partial, total, or non-barriered oxidation ditch having an endless channel. The header assembly may be vertically installed in the bottom of the contact duct or at an angle in the intake portion thereof as a mid-duct header assembly; it can additionally be installed in a horizontal position at the inlet of the contact duct as an inlet header assembly. Each header assembly comprises a liquid header, an air header, a plurality of jet aerators which are flow connected to both headers, stiffener plates which rigidly attach the headers to each other and to the jet aerators, and pipes connecting the headers to respective liquid and air supply lines. The mid-duct header assembly is slideably mounted within an access duct which is accessible from the surface.

Abstract: Improved methods apparatus are provided for introducing and entraining air into a waste liquid, thereby increasing the quantity of dissolved oxygen in the liquid to enhance the aerobic treatment process. A power driven propeller is preferably positioned at the discharge end of conical-shaped transition housing, and draws in air while waste water is controllably introduced to the transition housing from below the surface of the water. The housing upstream from the propeller is primarily an air chamber with incoming streams of water, while the housing downstream from the propeller is filled with waste water having minute entrained air bubbles. The water and entrained air are thus discharged downwardly, and the axis of the equipment preferably inclined to increase circulation in the waste water pond or tank. The techniques of the present invention have relatively low power requirements while substantially increasing gas concentration in the liquid.

Abstract: This invention provides an aerator comprising a jet stream generator for ejecting a gas and a liquid in a mixed state from a nozzle, and a tubular flow straightener for mixing the bubble-containing stream ejected from the nozzle with ambient water and discharging the resulting mixture from the discharge orifice thereof, characterized in that the flow straightener has a tubular form whose internal diameter is reduced from the inlet toward the discharge orifice through at least a part of its length.This aerator can produce a stream containing minute gas bubbles, even when a gas is supplied thereto in such a large amount as to give a gas-to-liquid volume ratio of 3/1.

Abstract: An apparatus for introducing a gas into a liquid comprising a container, at least one vertical conduit in fluid communication with the container, the conduit having therein at least one mixer assembly for breaking up gas bubbles into bubbles having small diameters, and a means for introducing a gas into the conduit at a point below the mixer assembly, the mixer assembly comprising at least two freely rotating turbines which are spaced apart axially and have different direction or speed of rotation.

Abstract: In an activated sludge process for the purification of wastewater, in a completely mixed tank in the presence of carrier particles for the microorganisms, the aerating gas feed creates a tubular spiral circulating flow of the wastewater about a horizontal axis extending from the inlet zone to the outlet zone of the tank. To avoid a buildup of the carrier particles in the outlet zone of the tank, the gas feed maintaining the circulating motion is reduced along the axis of flow with respect to the gas feed set in the initial zone of the flow path. Gas may also be sparged along an axis transverse to the flow near the outlet to create a tubular flow which also clears the carrier particles from the outlet.

Abstract: The present invention concerns a way in which to conduct oxygen or a gas containing oxygen into a counterbubble reactor according to the invention, preferably into the upper part of the reactor, and at all events distinctly above the bottom of the reactor; to disperse the gas in a sludge with high solid content, and to impart to the sludge a flow first in the counterbubble zone of the reactor downward, reversing in the vicinity of the bottom, and in the ascending zone of the reactor upwards, and thereby to achieve rapid dissolving of the gas in the sludge and efficient reacting of oxygen and sludge at low energy cost.

Abstract: In the treatment of livestock waste, liquid to be aerated is pumped from a storage container, holding pond or lagoon and drawn through a magnetic air inductor inlet then pumped into a conical chamber towards an outlet port at the narrow end of each of a series of conical chambers. Air is drawn into the chamber by pressure differential and intermingled with the liquid and waste to be treated to hydrolyze the fines as the material passes through the chambers. A conically shaped expansion cone attached as an extension of each chamber outlet port permits further expansion and intermingling of the air and liquid waste mixture. An open-ended sleeve is attached in surrounding relation to the outlet of each discharge cone so that the air/liquid stream from each cone is directed axially through its sleeve, each sleeve having a spiral baffle plate extending along the interior length thereof to further promote agitation of the mixture and most complete aerobic digestion of the fines.

Abstract: A process for operating a total barrier oxidation ditch to provide concentrated power input per unit volume of the downwardly pumped liquor-air mixture and high mixing turbulence at maximum contact depth and hydrostatic pressure.

Abstract: Method for purifying waste water in a compact settling plant, particularly for waste water which is biologically very loaded, wherein the final settling tank (23) is arranged inside a scavenging basin (3), wherein the aeration of waste is separated from the aeration of the return sludge, the two flows being mixed and previously degased before entering the scavenging basin and optionally once more contacted with a gas. Due to the star configuration of the aeration, suction and mixing units, a uniform charge and transformation are obtained so that at equal flow rate, the volume may be reduced with respect to conventional plants.

Abstract: A modified activated sludge system is provided wherein BOD-containing wastewater and recycled sludge are initially admixed under anaerobic conditions in the substantial absence of oxygen or oxidizing agents and subsequently subjected to aeration and clarification. By the disclosed operation the selective production of non-bulking biomass is favored while effective removal of phosphates is obtained. By a further alternative modification, nitrates and nitrites are also removed by interposing an anoxic treating zone between the anaerobic zone and the aerating zone.

Abstract: In a process for mixing a gas and a liquid in an apparatus having an axial flow down-pumping impeller located in a draft tube and preceded by a first baffle wherein a vortex and turbulence are created and gas is drawn into the vortex, the improvement comprising providing liquid velocity of at least one foot per second, increasing the turbulence, providing a second baffle below the impeller, and a high shear zone between impeller and the second baffle.