Abstract: A deionized water supplying system is connected to a deionized water supply tank, a deionized water supply pipe and a deionized water circulating pipe. The system includes a three-ported valve having a first port connected to the deionized water supply pipe via a first branch pipe, a second port connected to the first port when the three-ported valve is in a first state, and a third port connected to the deionized water circulating pipe via a second branch pipe and communicating with the first port when the three-ported valve is in a second state.

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: An improved barrier oxidation ditch is provided which has a channel portion for unaerated induced-flow and an inclined duct for aerated induced flow, whereby energy in the dammed-up momentum is more efficiently released. This induced-flow duct is inclided at 30.degree. to 60.degree. to the horizontal, preferably 45.degree., and is disposed upstream of, downstream of, or alongside of the circulator/aerator in the intake channel. The induced-flow duct is preferably rectangular in cross-section and may have its downstream wall formed by the baffle if it is downstream of the circulator/aerator. The induced-flow duct is connected at its lower end to the discharge duct to initiate a combined-flow portion thereof. This combined-flow portion has an upper side which may be a thin wall or may be a much thicker aerator bridge. A baffle may be mounted downstream of the inlet of the induced flow duct for selectively restricting the amount of unaerated induced flow.

Abstract: A method for classifying sand wherein a mixture of sand and water is introduced into a classification tank (7) partially filled with water. Depending on the weight of the sand grains, the grains of sand will precipitate at the bottom (8) of the tank (7) at graduated distances from an inlet pipe (6), the heavier particles nearest the inlet and the lighter particles farther away.To prevent large quantities of fines, i.e., sand grains between about 0.002 mm and 0.006 mm in size, from being lost by being washed out of the tank (7) together with the overflow water, the water from the tank (7) is recirculated by means of a pump (14) so that the water becomes progressively more saturated with fines, which means that larger amounts of fines will precipitate in the tank (7).Because the water is recirculated, water consumption can be reduced by 2/3, and at the same time the problem of the overflow water from the tank (7) is also reduced.

Abstract: A sludge remover and processor includes a first vessel holding cleaning liquid and a second, phase separating vessel. Cleaning liquid from the first vessel is sprayed against a dirty surface. A vacuum pump keeps the second vessel upper region at a partial vacuum so cleaning liquid and dislodged matter from the dirty surface is sucked into the second vessel. Solids and liquid are pumped from the second vessel into a solids separator where the larger solids are removed for disposal and liquid is pumped into a centrifuge which removes fine solid particles. The fine particles are mixed with a bulk solidification medium for disposal. Oil collection in the vessels is enhanced by the partial vacuum which lowers the boiling point so tiny bubbles are formed to aid separation of the oily and non-oily phases. Passing the liquid through a centrifuge also aids separation of the oily and non-oily phases in the first vessel.

Abstract: It has been found that by mounting a suction cover onto the periphery only of a suction interconnection member placed between the suction cover and the recirculating piping, and by carefully placing the hole pattern and size of the individual holes thereon, that a substantial increase in the allowable flow rate gpm for a given safe suction of below five pounds will be produced, as required by the IAPMO standards. Furthermore, it has been found that the suction cover should provide as clear and unobstructed a path to flow, to the internal bore of the suction interconnect member, as possible, and, to this end, the suction cover itself is completely free of any internal flow obstructions, as is the flow path to the internal bore of the suction interconnect.

Abstract: Method of separating blood, in particular for recovering thrombocytes and/or leucocytes, the whole blood coming from the donor being separated in a separation means of a centrifuge into an erythrocyte fraction, cell-poor plasma, a thrombocyte fraction and/or possibly a leucocyte fraction, the separated fractions of the blood being discharged via a flexible tubing system of discharge lines out of the separation chambers of the centrifuge and constantly predetermined amounts of separated cell-poor plasma returned to the whole blood to be separated or to the already separated erythrocytes in the separation chamber, and a separation apparatus for carrying out the method comprising a separator having one or more separating chambers connected together and a flexible tubing system which includes a supply line (1, 2) for the supply of the whole blood to be separated to the separator and discharge lines each for the separate discharge of the erythrocyte fraction (10), the cell-poor plasma (3, 5), the thrombocyte fract

Abstract: An oil content monitor/control unit system is configured to automatically nitor and control processed effluent from an associated oil/water separator so that if the processed effluent exceeds predetermined in-port or at-sea oil concentration limits, it is either recirculated to an associated oil/water separator via a ship's bilge for additional processing, or diverted to a holding tank for storage. On the other hand, if the oil concentration of the processed effluent is less than predetermined in-port or at-sea limits, it is discharged overboard.

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: A waste water treatment system including a vessel having a closed loop flow path, a bottom and a wall. A clarifier is mounted on the vessel wall within the vessel and includes a clarifier wall which is elongated in the direction of the flow path and is relatively narrowly spaced from the vessel wall. A clarifier wall extends from the bottom to a location above the intended level of waste water to define a clarifying chamber that is relatively narrow. Inlets may be located along the length of the clarifier wall and the bottom wall of the clarifying chamber may be provided with sludge outlets.

Abstract: A method and apparatus for biological aerobic treatment of wastewater wherein oxygen is induced into a mixed liquor flow path and a method and apparatus for separating the liquid withdrawn from the mixed liquor flow path into a clear liquid stream and a flock laden stream. A streaming specific gravity separator of unique construction and operation separates the mixed liquor into a clear liquid stream and a flock laden stream, withdrawing the clear liquid stream from the system and directing the flock laden stream back into the mixed liquor flow path. The separator functions within the system to be self-controlling for load increases or decreases.In accordance with preferred embodiments of the system, the separator may be positioned inside or outside of an oxidation ditch. The separator may also be utilized in combination with an aeration basin.

Abstract: A domestic well water system, rendered unusable by volatile contaminants in the groundwater, can be restored to use by installing an aerator in a flow path such that water is continuously pumped, by the existing well pump, out of the well, through the aerator, and back to the well through the well head. Water is diverted from this flow path for use. The well serves as a storage device, and water returned from the aerator to the well mixes with water in the well and serves as a buffer to encroachment by contaminated groundwater.

Abstract: When treating water with ozone, chlorine or similar reagents, the problem arises of introducing the gas as inexpensively as possible at the extraction point which is frequently located in a considerable depth of water--typically 30 to 59 meters. It is proposed that the gas be introduced into a bubble column downflow reactor (7) in the region close to the surface by means of a mixer and the gas bubbles forming there be passed against buoyancy through the reactor to the lower end of the riser (3) of the pump arrangement, where it is intimately mixed with the fresh water drawn in. After passing through a gas separator (8) and a pump, a part of the heated water is recycled to the mixer (8).

Abstract: An improved barrier oxidation ditch is provided which has an inclined duct for the induced flow, whereby energy in the dammed-up momentum is more efficiently released. This induced-flow duct is inclined at 30.degree. to 60.degree. to the horizontal, preferably 45.degree., and is disposed upstream of, downstream of, or alongside of the circular/aerator in the intake channel. The induced-flow duct is preferably rectangular in cross-section and may have its downstream wall formed by the barrier if it is downstream of the circulator/aerator. It is connected at its lower end to the discharge duct to initiate a combined-flow portion thereof. An in-channel clarifier, disposed in the discharge channel so that its upstream wall is the barrier and its solid bottom is the ceiling of the combined-flow portion of the discharge duct, provides prolonged bubble retention time at maximum hydraulic pressure, whereby the efficiency of oxygen transfer is increased.

Abstract: This invention provides apparatus for the growth of biomass from a supply of suitable nutrient wherein the volume of biomass and the size and shape of the units in which it is present within a vessel (10) in which the reaction takes place can be accurately controlled. Control is achieved by providing a support structure (14) for the biomass comprising one or more movable bodies each of which has an internal reticular structure defining a substantial voidage therein and which essentially fills with the biomass but which does not overfill since excess growth is restricted. Restriction can be achieved by removal of excess biomass or by removal of the bodies at the time that they become filled. The techniques are capable of numerous industrial applications including various biological fermentation processes as well as the purification of sewage and industrial effluents, for example.

Abstract: A process is described for pumping and aerating the mixed liquor within the endless channel of an oxidation ditch by using a pump/aerator to form an aerobic zone which has a selectively located planar end, where an anoxic zone begins, and within which biological nitrification of NH.sub.3 -N occurs. A pump/circulator, to which inflowing raw wastewater and return sludge are fed, is located approximately at this planar end to provide point-source mixing of the wastewater and return sludge, whereby the five-day biological oxygen demand of the wastewater is oxidized within both the aerobic and the anoxic zones and the nitrate ions formed within the aerobic zone are denitrified within the anoxic zone. Finally, an oxygen-deficient zone, wherein the mixed liquor is deficient in both dissolved oxygen and NO.sub.3.sup.- and NO.sub.2.sup.- anions and is ready for luxury uptake of oxygen within the pump/aerator, is dependably provided at the end of the anoxic zone.

Abstract: A dual baffle pump/aerator assembly comprising a concave intake baffle which is disposed upon the floor of an endless channel of an oxidation ditch to intercept the flow of mixed liquor within the channel. A horizontal barrier having aeration means associated therewith is disposed above and attached to the intake baffle. A concave discharge baffle is disposed above and attached to the horizontal barrier.

Abstract: A mixing-control apparatus for continuously moving mixed liquor having translational-flow momentum within an endless channel of a closed-circuit oxidation ditch, conserves at least of the portion of the momentum by enabling induced flow of the mixed liquor through adjustable openings in the barrier.

Abstract: The invention relates to an apparatus for the treatment of liquids, in particular for the biological purification of household sewage and/or industrial sewages containing organic contaminations, furtheron for the aeration and/or sedimentation of liquids. In the circular, quadratic or elongated oblong basin receiving the liquid a path recurring in itself is formed by means of one or more partition walls. For moving the liquid in a horizontal and/or horizontal and vertical direction propellers and/or rotors with a horizontal and/or vertical axle are used.For the aeration of the liquid one or more aerators with a horizontal or vertical axle and/or one or more fixed air blowers are applied.In sense of the invention one or more secondary sedimentators in a longitudinal arrangement or with a circular top-view, provided with oblique lamellae, are connected directly to the object or are assembled therewith.

Abstract: In aerobic wastewater treatment systems, such as sewage treatment, liquid in a channel spanned by a liquid-tight barrier is moved past the barrier by a liquid-gas contact pump, thus dissolving a gas in the liquid and creating a differential head that provides flow energy for moving the liquid in plug-type flow through the channel, which is preferably a continuous-flow pipeline or a circuit-flow oxidation ditch, without energy-wasteful vertical circulation. The barrier further provides a structure for mounting submerged static aerators or a draft tube, in combination with a surface aerator, such as a submerged turbine or surface-disposed impeller aerator, as the liquid-gas contact pump. The barrier is disposed at sufficient depth, when combined with static aerators or when telescopically attached to the draft tube of a floating surface aerator, to enable the liquid level to be selectively varied so that flow equalization to an oxidation ditch and wastewater storage therewithin are provided.

Abstract: A method and apparatus for the anaerobic treatment of wastewater containing organic matter. The apparatus includes a closed tank to which the wastewater is delivered through liquid inlet means below a reaction hood. The reaction hood defines a mixing zone in which influent water mixes with liquid and biological solids already in the zone. A portion of the liquid being mixed is withdrawn and passed through a gas separator which removes entrained gas and returns the liquid to the tank. The tank may include fixed film media for improving treatment efficiency. Other features of the invention are the use of a sludge thickener for concentrating sludge removed from the tank and the use of a second gas separator in a treated effluent conduit from the tank. That separator has an adjustable baffle or weir which can be raised to flush scum into surface launders in the tank.

Abstract: A barriered pump/aerator, for continuously moving and aerating mixed liquor having translational-flow momentum within an endless channel of a barrier oxidation ditch, conserves at least a portion of the momentum by enabling induced flow of the mixed liquor past the barrier. In one embodiment, the induced flow passes through a discharge slot which contains a plurality of jet aerators. In another embodiment, the induced flow passes through a trough formed in the bottom of the endless channel past an inclined baffle. In a third embodiment, the induced flow passes through a tubular passage having a plurality of jet aerators disposed therein.

Abstract: A reactor for the anaerobic digestion of organic sludge and for the production of methane gas, comprises an essentially horizontal cylindrical vessel provided with an agitator rotating around an essentially horizontal shaft, an inlet for introducing the sludge to be digested at one end of said vessel, at its opposite end an outlet for removing the digested matter from the vessel and in the upper portion of the vessel an outlet/outlets for the recovery of methane gas. For returning the solids settled on the bottom of the vessel from the outlet end of the vessel to the inlet end of the vessel, the vessel comprises a channel connecting the outlet end of the vessel with the inlet end of the vessel and a device for guiding the solids to the front of the return channel and for their transport through the return channel by means of gas.

Abstract: An integral clarifier is provided that operates without a pump by deriving the clarifier feed stream and its accompanying pump head from the flow being pumped through the draft tube of a draft tube circulator/aerator assembly in a complete mix system or in a basin oxidation ditch. The clarifier feed stream is delivered to the clarifier with this pump head substantially intact to create a differential hydraulic head between the surface of the clarified liquor within the clarifier and the surface of the mixed liquor within the complete mix tank or within the endless channel of the barrier oxidation ditch. The clarifier may be located in any suitable place but is preferably alongside the complete mix tank or alongside the discharge channel of the barrier oxidation ditch, within the discharge channel so that its upstream side forms the barrier, or surrounded by the endless channel, particularly if the clarifier and the ditch are circular in shape.

Abstract: This invention provides apparatus for the growth of biomass from a supply of suitable nutrient wherein the volume of biomass and the size and shape of the units in which it is present within a vessel (10) in which the reaction takes place can be accurately controlled. Control is achieved by providing a support structure (14) for the biomass comprising one or more movable bodies each of which has an internal reticular structure defining a substantial voidage therein and which essentially fills with the biomass but which does not overfill since excess growth is restricted. Restriction can be achieved by removal of excess biomass or by removal of the bodies at the time that they become filled. The techniques are capable of numerous industrial applications including various biological fermentation processes as well as the purification of sewage and industrial effluents, for example.

Abstract: A waste water treatment system including an oxidation vessel which receives waste water and has at least one wall and is adapted to introduce oxygen into the waste water contained therein. A clarifier is mounted on the wall at the outlet from the vessel and is narrow in comparison to the vessel. The clarifier includes generally vertical end walls and an imperforate elongated generally vertical sidewall defining upper and lower ends of the clarifier. The lower end of the clarifier is opened to provide for admission of waste water into the clarifier and an apertured plate extends along the length of the clarifier at the upper end and is hydraulically interposed between the clarifier and the vessel outlet.

Abstract: This flow-control apparatus for an oxidation ditch comprises a barrier which divides a channel of an oxidation ditch into an intake channel and a discharge channel, at least one submerged turbine which pumps mixed liquor from the intake channel, and at least one discharge duct which connects each turbine to the discharge channel and passes beneath the barrier. Compressed air is supplied to each turbine and/or to each discharge duct. Activated sludge is fed to the anoxic portion of the ditch and/or to each turbine which provides complete mix and propels the mixed liquor in plug-type flow through the channels of the oxidation ditch. By selectively and independently controlling turbine speed and amount and/or feed location of compressed air, the timed aerobic/anoxic ratio for the ditch can be controlled in accordance with independent parameters, such as seasonal temperatures.

Abstract: A barriered circulator/aerator in the endless channel of a barrier oxidation ditch provides a directly pumped flow of mixed liquor into a central liquor inlet zone and an energy-release induced flow of mixed liquor into a surrounding liquor inlet zone at the inlet of a deep oxygen contact duct which passes beneath the barrier to the discharge channel on the downstream side thereof. It further provides mixing of diffused air with the directly pumped flow and/or the induced flow and then moving the combined air-liquor flows into the deepest portion of the contact duct where point-source pressurized aeration of both flows occurs. Eddy jet diffusers are preferably used for aerating the induced flow. Oxygen transfer efficiencies are obtained that are 1.6-2.2 times as great per brake horsepower per hour as that attainable by 100% pumping of the mixed liquor in a total barrier oxidation ditch, as disclosed in U.S. Pat. No. 4,260,278.

Abstract: Methods are provided for converting both plug flow and complete mix basins of the prior art into barrier oxidation ditches. Circulator/aerators are described that can be prefabricated and dropped onto the floor of an existing basin so that, in combination with at least one partition, if needed, an endless channel is created with minimum disruption of the activated sludge process.

Abstract: A water purifier comprising a cylinder provided at its lower portion with an air chamber and water sucking holes and adapted to be intermittently supplied with compressed air and water, a honeycombed tube structure including a multiplicity of tubes arranged in a side-by-side relation concentrically around the cylinder and a protecting sleeve for protecting the honeycombed tube structure. The protecting sleeve may be provided on its outer peripheral surface with a buoyancy chamber. A plurality of units of water purifier may be arranged in stages. In some cases, the water purifier is placed to occupy the whole space of a water tank into which the water to be treated is introduced continuously.

Abstract: An on-location sewage treatment apparatus comprises a tank and a cylindrical wall therein arranged to form therewith a plurality of series-connected pre-treatment compartments. A grinder receives and grinds sewage-containing liquid and introduces same in the form of a colloidal mixture into a first of the pre-treatment compartments. The colloidal mixture gravitates between the pre-treatment compartments, the waste matter being aerobically consumed by bacteria therein. A second cylindrical wall spaced inwardly of the first endless wall forms therewith an intensive treatment compartment which receives pre-treated liquid. An upright porous sheet in the intensive treatment compartment is arranged in a circular accordian-pleated configuration. The sheet supports a bacteria culture thereon which consumes waste matter in the mixture passing through the sheet. Pure oxygen gas is introduced into each of the compartments and includes a sound wave generator for dispersing the oxygen gas.

Abstract: A process for the regeneration and recovery of a loaded adsorbent which comprises the steps of:(a) contacting the loaded adsorbent with an alkaline solution for a period sufficient to effect regeneration of the adsorbent;diluting the resulting slurry of the adsorbent in the alkaline solution with recycled overflow liquid from one or both of the subsequent separation steps, to thereby reduce the concentration of adsorbent in the slurry to at least the level where unhindered settling can occur;(c) separating the slurry to give a first liquid overflow and a first solids underflow containing the adsorbent and discharging at least a portion of the first liquid overflow to waste, the remainder (if any) being returned to step (b);(d) slurrying the first solids underflow from step (c) with washwater and recycled second liquid overflow from the subsequent separation step;(e) separating the thus formed slurry to give a second liquid overflow and a second solids underflow containing the adsorbent and returning a portion

Abstract: A method of aerating liquids, particularly for aerobic growing of microorganisms, has the steps of forming a circumferential stream of liquid, forming a longitudinal stream of liquid, and superimposing these streams so as to form a combined closed spiral-shaped stream. An arrangement is provided in which the circumferential stream is formed by an upright conduit tube and an impeller, the longitudinal stream is formed by a distributing element with a plurality of nozzles, and the superimposing of the streams is attained by fixedly mounting the distributing element relative to the impeller.

Abstract: Methods are provided for converting both plug flow and complete mix basins of the prior art into barrier oxidation ditches. Circulator/aerators are described that can be prefabricated and dropped onto the floor of an existing basin so that, in combination with at least one partition, if needed, an endless channel is created with minimum disruption of the activated sludge process.

Abstract: A sewerage aerator is illustrated having an air feed diffuser with air opening adjustably positioned approximate venturi throat located above the liquid sewerage tank level and having means to introduce the liquid sewerage to the upper venturi chamber and cause it to flow past the air openings.

Abstract: An on-location sewage treatment apparatus comprises a tank and a cylindrical wall therein arranged to form therewith a plurality of series-connected pre-treatment compartments. A grinder receives and grinds sewage-containing liquid and introduces same in the form of a colloidal mixture into a first of the pre-treatment compartments. The colloidal mixture gravitates between the pre-treatment compartments, the waste matter being aerobically consumed by bacteria therein. A second cylindrical wall spaced inwardly of the first endless wall forms therewith an intensive treatment compartment which receives pre-treated liquid. An upright porous sheet in the intensive treatment compartment is arranged in a circular accordian-pleated configuration. The sheet supports a bacteria culture thereon which consumes waste matter in the mixture passing through the sheet. Pure oxygen gas is introduced into each of the compartments and includes a sound wave generator for dispersing the oxygen gas.

Abstract: A process and apparatus for purifying polluted natural and artificial water pools by directly injecting pressurized oxygen into the deep layers of the pool water and recovering the undissolved oxygen, not used up by the pollutants, for recycle and reuse in the process by means of a collector device.

Abstract: This invention provides a method for treating wastewater by circulating wastewater around a system comprising a downcomer and a riser which communicate directly at their lower ends, the level of the wastewater in the downcomer being maintained above the level of the wastewater in the riser to provide a hydrostatic pressure head which causes circulation of the wastewater around the system, supplying a gas containing oxygen to the wastewater as it passes through the downcomer, pumping the wastewater from the top of the riser back into the top of the downcomer and removing treated wastewater from the riser at the same rate as wastewater is introduced into the system characterized in that the height of the hydrostatic pressure head is controlled by adjusting the height at which treated wastewater is removed from the riser and the level of the wastewater in the riser. The invention also provides an apparatus for putting the method into practice.

Abstract: A process and apparatus for treating wastewater with oxygen in which the wastewater is circulated on a horizontal course and is exposed to the introduction of oxygen or oxygen-enriched air in one or several sections of its course whereas it is exposed to the atmosphere on the remainder of its course. Oxygen of a higher concentration than atmospheric oxygen is contacted at least intermittently with the water surface and introduced into the wastewater through agitation of the water surface. At least a part of the total volume of the wastewater is treated by carrying out alternately at least two of the following three modes of operation: (a) surface aeration of the wastewater using atmospheric air; (b) oxygenation while maintaining atmospheric pressure above the wastewater; and (c) oxygenation while maintaining positive pressure above the wastewater with the operating modes alternating with each other in response to variations in the volume and/or character of the wastewater being treated.

Abstract: Self-contained treatment apparatus for a body of water includes a mounting assembly having flotation elements for fixedly supporting a circulation or agitation device below the surface of the water and driving or motor mechanism above the water surface. Actuation of the motor mechanism operates the circulation or agitation device such that naturally occurring oxygen-saturated water near the surface is drawn downwardly and mixed with the lower oxygen deficient reaches of the body of water and effecting a net increase in dissolved oxygen content. Optionally, actuation of the motor mechanism operates a bubble generator adjacent the water surface so that the air bubbles generated are drawn down with the oxygen-saturated surface water, where oxygen from the bubbles dissolves into the surrounding oxygen-deficient water, thus accelerating the improvement in dissolved oxygen content.

Abstract: A sewage treatment system comprising means defining a receptacle including at least one chamber for receiving a body of sewage composed of liquid and solids the top of which is exposed to air, means for applying air, under pressure, immediately below the upper surface of said body of sewage in said one chamber, at an angle thereto to physically lift portions of said sewage from the upper surface of said body thereof in a spray form, thereby to expose said lifted portions to air and to infuse said portions with oxygen, the nature and angle of application of the air being effective at the same time to induce a current in the body of sewage having a downward spiral and an ever-decreasing velocity, said current being effective to induce suspended solids to be driven to the bottom of said chamber together with the heavy solids settled thereon, thereby to facilitate an extremely rapid aerobic digestion.

Abstract: A method and apparatus for treating wastewater by circulating it around a system comprising a downcomer and a riser communicating with each other at their lower ends, the level of the wastewater in the downcomer being above the level of the wastewater in the riser and providing a hydrostatic pressure head which causes circulation of the wastewater around the system, supplying a gas containing free oxygen to the wastewater as it passes through the downcomer, and pumping the wastewater up from, or from near, the top of the riser to a part of the downcomer, at or near the top thereof, which has, for at least a part of its length, a cross-sectional area which is less than the cross-sectional area of the remainder of the downcomer below the said part.

Abstract: An aeration system for treating solid biological waste, and the like, has a fluid circulating device disposable in a tank holding a slurry of solid and liquid to be treated for drawing air and slurry from a surface portion of the slurry in the tank and discharging the air and slurry adjacent the bottom of the tank. The circulation device has a propeller pump disposed in a duct having an inlet and an outlet forming the fluid path through the slurry, with a float assembly being connected to the duct adjacent the inlet thereof for positioning the inlet adjacent the surface of the slurry in which the duct is immersed.

Abstract: An improved long vertical shaft bioreactor for the treatment of degradable waste is provided wherein the head tank or basin surmounting the vertical downcomer and riser chambers is surrounded by a foam oxidation vessel. Conduits are provided between the head tank and the foam vessel through which (a) foam accumulated in the head tank is passed to the foam vessel and (b) through which excess fluid in the head tank may be vented.

Abstract: Solids-liquid separation, wherein a solids-liquid mixture containing dissolved oxygen-containing gas is circulated around a circulatory system comprising a downcomer and a riser, part of the mixture in the riser being introduced into a flotation chamber in which the hydrostatic pressure gradually decreases as the mixture flows upwards, with consequent release from solution of gas bubbles which carry solid particles to the top of the mixture.

Abstract: A fluid purification system for performing filtration of particles from a feed liquid by a tangential flow of the feed liquid over a membrane surface. In one embodiment, the purification system includes a filter cartridge contained within a filter housing having ports permitting ingress and egress of feed liquid and filtrate. The cartridge includes a filter element having a layered construction with a thin flow channel between the layers. One layer of the filter element is formed of a sheet of impervious material defining one wall of the thin flow channel. Another layer of the filter element is spaced from the one layer and formed of a sheet of permeable membrane material and defines another wall of the thin flow channel. The spacing between the walls of the thin flow channel is maintained by a sheet of reticular material that provides turbulence in the thin flow channel to promote cross flow filtration. The filter element is formed into a pleated, cylindrical shape with a flow axis parallel to the pleats.

Abstract: Apparatus is described for purifying or desalinating relatively small quantities of water using one or a few membrane units with relatively modest power requirements. The apparatus uses a pump, an eductor or a combination of both in recirculating a portion of the feed water through a reverse osmosis membrane assembly. The method includes recirculating a portion of the feed water through the membrane assembly and discharging a portion of the recirculated feed water from the system.

Abstract: An aerator for the treatment of liquid by immersion in the liquid to form in the liquid a liquid stream and introduced gas bubbles. The stream is to be produced with efficient use of power to have sufficient bubbles small enough to avoid waste by bubbles reaching the surface too quickly. The aerator has a pressure chamber (49), with a liquid inlet and gas inlets (422) positioned between the liquid inlet and a restricted outlet throat (47) associated with a chamber wall surface (44) arranged to direct an outlet stream deflected from the liquid inlet direction. The aerator can be formed without immersed moving parts by two tubes, a smaller inner one (41) expanding toward an outer larger one (42) to define the throat and pressure chamber and wall surface. The gas supply is applied through holes large enough to resist algal obstruction at a position where the gas and water enter a part of the pressure chamber of reducing cross-section for subsequent deflection out of the throat.

Abstract: The efficiency of membrane separation is enhanced in a hyperfiltration process by scooping off controlled amounts of the boundary layer at desired points along the flow path where useful concentrations have been achieved avoiding the necessity of bringing the entire flow up to desired concentration. The use of porous stainless steel supports with membranes formed therein in situ after fabrication from the pipe sections in a single pass configuration is especially advantageous with scoop apparatus spaced along the length of the stainless supports.

Abstract: High purity water distribution systems are purged and disinfected by incorporating an outlet purge line into the conventional recirculating loop of the prior art. The purge line communicates with each outlet opening of the high purity water system and means are provided for intermittently and sequentially purging the outlets.