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 side skimmer provided in a channel containing flowing liquid includes a skimmer mechanism and a skimmer drain. The skimmer mechanism includes a fixed portion secured in a hinge-like manner to one side of the channel and aligned with an obstruction located partially across the channel width, and a movable wing-like portion extending above and below the liquid surface. This mechanism selectively deflects the flow into the drain, and is movable between a closed position, which allows free flow between the mechanism in the channel side and the obstruction, and an open position between the fixed portion and the obstruction, which directs flow to the skimmer drain. The skimmer drain is vertically movable between a closed position above the liquid surface, and an open position just below the surface whereby floating matter is removed.

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wastewater wherein oxygen is induced into a mixed liquor flow path and a method and apparatus for separating the liquid withdrawn from the mixed liquor flow path into a clear liquid stream and a flock laden stream.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: 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: 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: Liquid is caused to circulate in a shallow tank which has an operational depth less than half the effective maximum distance across the tank. One wall 17 defines with another wall a corner 18 and a bubble curtain 19 is provided along the wall 17 adjacent the corner 18 which imparts to the liquid in the tank an upward vertical component of movement which is asymmetrical along the wall 17, causing greater vertical movement of liquid at said corner than at the other end of the wall. Liquid rising up the wall 17 moving away therefrom by reaction therewith will circulate with a horizontal component due to the asymmetrical arrangement of the bubble curtain. The invention can be applied to the separation of materials of different densities e.g. the separation of suspended solids or emulsified oils from waste water.

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 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: 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: 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: In a ring channel aeration system, circulation is provided by one or more hydraulic jumps while the major portion of the energy consumed in aeration is allocated to the release of oxidative process gas through horizontally non-propulsive bubble release means having an oxygen transfer efficiency of at least about 6. The hydraulic jump(s) may be powered by discharge of gas (e.g. the same gas used for aeration) through gas discharge means, in which case the system of gas discharge means and bubble release means may have an overall oxygen transfer efficiency of at least about 6. The invention has advantages of flexibility and resultant energy savings as compared to single device circulation/aeration systems, in that excessive energy need not be consumed in aeration to obtain the requisite circulation and vice versa.

Abstract: An intrachannel clarifier for producing clarified waste liquid within an oxidation ditch aerobic wastewater treatment system. The clarifier comprises a tank-like construction positioned in the upper portion of the oxidation ditch channel and having an opening in an upstream wall for admitting mixed liquor at a relatively slow rate. The region within the clarifier establishes a quiescent zone where solids may settle from the waste liquid by gravity to the tank bottom. A portion of the clarified liquid is removed by means of an overflow weir or launder. The bottom of the clarifier forms a perforated baffle made up of a plurality of spaced parallel slightly overlapping inverted V-shaped angle members extending between the walls of the oxidation ditch channel. The spaces between the angle members permit settled solids to return to the mixed liquor flowing beneath the clarifier, but prevent movement of excessive quantities of mixed liquor into the quiescent zone.

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 biogas generator which includes a medium conducive to the growing of plants that are floating and of the family that includes water hyacinths, lily pads, and elodea; a conveyor for transferring the free floating plants from the growing area to a decomposition area including a canopy adapted to entrain therewithin biogas given off by decomposing plants constrained thereunder, and an instrumentality for scavenging the biogas generated therein to a remote area for subsequent use and or compression.

Abstract: A process for gas production and accelerated bioleaching of organic materials by acid forming bacteria in beds of organic solids, such as landfills, passing the leachate of hydrolysis and liquefaction products of microbial action of the microorganisms with the organic material to an acid phase digestion zone to regenerate an activated culture of acid forming microorganisms for recirculation to the bioleaching zone. The supernatant from the acid phase digestion zone may be passed to a methane phase digestion zone operated under conditions to produce methane rich gas. The supernatant from the methane phase digestion zone containing nutrients for the acid forming microorganisms and added sewage sludge or other desired nutrient materials may be circulated to the acid phase digestion zone or to the bioleaching zone. Low Btu gas is withdrawn from the acid phase digestion zone while high Btu gas is withdrawn from the methane phase digestion zone and may be upgraded for use in SNG.

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: Each face of the disc for sewage aeration includes a multiplicity of recesses. The recesses of one face have no communication with those of the other face and are precisely dimensioned so that the sewage, which is essentially water, flows into and out of each recess without leaving an accumulation of deposits in the recess. This is accomplished with no reduction of and possibly an increase in the aeration efficiency of the disc.

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: A process for improved gas production and accelerated stabilization of landfills by accelerated in situ bioleaching of organic wastes by acid forming bacteria in substantially sealed landfills, passing the leachate of hydrolysis and liquefaction products of microbial action of the microorganisms with the organic material to an acid phase digester to regenerate the activated culture of acid forming microorganisms for recirculation to the landfill, passing the supernatant from the acid phase digester to a methane phase digester operated under conditions to produce methane rich gas. The supernatant from the methane phase digester containing nutrients for the acid forming microorganisms and added sewage sludge or other desired nutrient materials are circulated through the landfill. Low Btu gas is withdrawn from the acid phase digester while high Btu gas is withdrawn from the methane phase digester and may be upgraded for use as SNG.

Abstract: There is provided a system for treating wastewater having a tank and a partition mounted in the tank to define an endless circuitous channel. An aerator and impeller is mounted in the tank to cause the liquid to flow through the channel. A clarifier is disposed in the channel and has a liquid outlet in its upper portion.

Abstract: A process for treating wastewater with oxygen in which 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. 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.

Abstract: In the activated sludge process for treating wastewater loss of biologically active microorganisms from the aeration-mixing tank to the clarifier is reduced and the biological process whereby wastewater is treated is made more efficient by the addition of inert solid particulate matter to the liquid while in the aeration tank to provide mobile sites upon which the organisms will attach and grow.

Abstract: Dual baffle aerators 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) can also be combined with dual-baffle aerators.An adjustably apertured barriered pump assembly is opened sufficiently to conserve momentum in the translationally flowing liquor while preventing back-mixing of aerated liquor.Processes for providing point-source or multi-source aeration, by using two or more barriered pump assemblies, can be provided at one barrier and the advantages of point-source homogeneous aeration can be provided at another barrier, at least one barrier being adjustably apertured.

Abstract: A flowing liquid system in which means are provided for simultaneously aerating and circulating said liquid comprising surface aerator means cooperating with partition means extending into a communication section between a first channel and a second channel with the aerator means located on the second channel side of and separated from the partition means and closer to the partition means than to the outside of the communication section, said system being particularly suited for use in an activated sludge waste water treatment system.

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.