JPH0523839B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the dissolution of gases into liquids in which the gases are only slightly soluble. The invention particularly relates to dissolving oxygen in water, for example as part of a treatment process for sewage or other aquatic wastes or effluents having biochemical oxygen demands.

Until now, wastewater has been treated using aerobic microorganisms that destroy harmful substances. Supply air to the wastewater to provide microorganisms with the oxygen they need for respiration. A typical sewage treatment method involves supplying air to the sewage and contacting it with an "activated sludge" containing the necessary aerobic microorganisms; two layers, the other containing activated sludge, are allowed to settle. Clean water overflows from the upper layer. Typically, municipal wastewater treatment also includes a pre-sedimentation step in which coarse solids are removed prior to treatment of the activated sludge. The activated sludge and sedimentation are carried out in a conventional manner in separate containers, as the wastewater is agitated to facilitate dissolution of air therein.

For example, British Patent Specifications Nos. 1,596,311 and 1,602,832 by the inventors of the present invention disclose that the treatment of oxygenated sewage with bacteria or activated sludge can be carried out in the same container as that used for sewage cleaning. Proposed. This method therefore reduces the number of tanks required for the treatment of sewage and therefore reduces the need for owners of e.g. industrial plants producing sewage or aquatic wastes with biochemical oxygen demands. is an attractive method.

It is necessary to ensure that the treatment with oxygen does not disturb the purification process. It has been proposed to oxygenate the incoming wastewater and the recycled liquid stream containing the wastewater outside the treatment vessel and direct the flow into the vessel at a relatively low velocity. One known oxygen treatment device that addresses this need uses two concentric, vertically arranged cylindrical chambers, one larger in diameter than the other. The upper chamber is open at the lower end and forms an entrance to the lower chamber. An annular flange is mounted between the lower end of the upper chamber and the upper end of the lower chamber to provide a fluid tight seal therebetween. Oxygenated wastewater is introduced into the top of the upper chamber via an inlet and forced to flow downward and through the lower chamber. From there, the wastewater is discharged into the liquid being treated. Typically, the liquid to be treated with oxygen is passed continuously through the oxygen treatment device. The flow of liquid through the upper chamber allows extended contact time between the oxygen bubbles and the wastewater. As the wastewater passes from the upper chamber to the lower chamber, its velocity decreases so that gas bubbles tend to collect in the lower chamber and then rise through the upper chamber to the disturbed compartment, where the gas bubbles You will be led underwater. This disturbance reduces the size of the gas bubbles and causes them to flow back into the chamber.

Devices such as those described above are relatively large and difficult to handle. Furthermore, it is known that the annular plate sealing between the two chambers is subjected to several tons of force which can cause it to deflect and eventually leak. It is also possible to reinforce the plate inside the lower chamber, but this may lead to structural difficulties and may have a negative impact on the efficiency of the oxygen dissolving device. For example, when treating coarse wastewater with oxygen, rags and other materials in the wastewater can become trapped in the reinforcement and clog the oxygen treatment equipment.

It is an object of the present invention to provide an in-liquid oxygen treatment suitable for the use of sewage (or other aquatic wastes having a biochemical oxygen demand) in a vessel for both biochemical treatment and purification. That is, to provide an alternative method and apparatus for dissolving gases.

According to a first aspect of the invention, a method of dissolving a gas in a liquid in which the gas is slightly soluble includes drawing a flow of fluid from said liquid, pressurizing the flow, and dissolving a small portion of oxygen. introducing oxygen into the pressurized stream so as to dissolve the undissolved oxygen, carrying the undissolved oxygen in the stream in the form of bubbles, and injecting the stream into an open-ended chamber, filling the chamber with liquid the stream draws a stream of liquid into the chamber from outside the chamber, the stream drawn into the chamber mixes with the liquid, and the resulting mixed stream is placed on the discharge side of the outlet of the chamber. A method is provided for dissolving a gas, characterized in that it includes an upstream velocity reduction process.

The present invention also provides a device for suctioning and pressurizing a flow of liquid from a container containing liquid, a device for introducing gas into the flow, and an end portion located in the container and immersable in the liquid. an open chamber and at least one nozzle having an outlet located near or within the chamber and communicating with an outlet end of the suction device; An apparatus for carrying out the method as described above is provided, characterized in that it has an upstream section for introducing a flow of liquid into the chamber from an intermediate mixing section and a downstream deceleration section.

Preferably, the chamber is generally tubular.
the upstream section has a wall that converges to the intermediate section;
Conveniently, said downstream section has a wall section extending from said intermediate section.

Preferably, said flow is introduced into said chamber as a jet through one or more nozzles typically located within or just upstream of an upstream portion of said chamber.

The injection nozzle is typically concentric within the cylindrical chamber. If desired, the chambers may be arranged generally vertically or inclined at a small angle to the vertical.

The method and device according to the invention are particularly suitable for use in the oxygen treatment of wastewater in wastewater treatment processes of the type in which the bacterial or activated sludge treatment of the wastewater is carried out in the same vessel as the purification of the wastewater.

In the foregoing method, the chamber is separated from the clarified liquid within a volume of a suspended active sludge (or the like), typically by a sedation box, or by a suitably arranged deflection device, or both. is preferably located at the top of the container.

Typically, by introducing a liquid jet into the chamber, the disturbance generated within the chamber reduces the size of undissolved bubbles of gas and promotes their dissolution in the liquid. However, typically all gases do not dissolve immediately. It is not necessary to dissolve all the gas in the chamber. In fact, by locating the chamber generally vertically and by locating its outlet below the inlet, the velocity of the liquid leaving the chamber can be slightly increased by making it faster than the final rate of rise of the bubbles. The foam may be allowed to exit the chamber along with the liquid leaving the chamber. Previously, it was thought that wastewater treatment methods in which purification and biochemical treatment are carried out in the same container would be adversely affected by the above-mentioned discharge of undissolved gas bubbles. believe that by preventing substantially all of the foam from entering the purification liquid, the aforementioned adverse effects can be largely eliminated. To achieve this purpose, it is preferable to use baffles to facilitate the upward movement of gas bubbles away from the clean liquid.

In another preferred embodiment of the invention, the inlet to said chamber is located close to the surface of a liquid mixture containing aerobic microorganisms involved in the biochemical treatment of aqueous wastes, so that the liquid mixture from said surface is Preferably, a flow of is introduced into said chamber. This helps break up the layer of scum or oily material that forms the top of the surface of the mixed liquid.

If desired, a baffle or baffle may be located outside of each chamber, but close to its outlet. Typically the baffle plate is positioned generally perpendicular to the axis of the chamber.

According to a second aspect of the invention, in a method for treating sewage or other aquatic waste having a biochemical oxygen demand, the upper part is provided with a deenergization chamber (and/or a similar distractor). in a tank having a board), an amount of sewage containing suspended aerobic microorganisms involved in the biochemical treatment of sewage is placed in the lower part, an amount of said sewage is placed in the upper part of the wastewater chamber, and an amount of said sewage is placed in the lower part of the tank. A certain amount of clean water, at least the upper part of which surrounds the energy reduction chamber, is superimposed on top of the input waste water, and a flow of waste water is drawn out from the lower part of the tank, and the drawn flow is used as a source of the incoming waste water. combining the streams, oxygenating the combined streams, introducing the oxygenated liquid in at least one stream into a deenergization chamber, directing the stream to a volume of wastewater below said tank, and at the bottom of the tank so that a flow of liquid deflected by a horizontal velocity component from the tank does not flow upwardly into the lower volume of waste water, generally near the boundary between the lower volume of waste water and the purified water. into an open-topped chamber (or baffle device) located opposite to and having generally vertical walls, characterized in that the oxygen treatment is typically carried out by the method according to the first aspect of the invention. A method of treating sewage or other water-soluble waste is provided.

The present invention also comprises a deenergization chamber (and/or a diversion device with a similar function) in the upper part to direct a volume of wastewater downwards containing suspended aerobic microorganisms involved in the biochemical treatment of the wastewater. a tank for introducing an amount of said sewage upward into said deenergization chamber and overlaying an amount of purified water on top of said lower sewage so that at least an upper portion thereof surrounds said deenergization chamber; A device for draining or spilling clean water from the water; a device for withdrawing a stream of wastewater from the lower portion of the tank and combining that stream with an incoming stream of wastewater; and an oxygen treatment device for treating the combined stream with oxygen. a device for introducing the oxygenated liquid in at least one stream into the deenergization chamber; and, when the entire device is operated, directing the flow of liquid deflected by a horizontal velocity component from the bottom of the tank generally into said downward direction. near the boundary between sewage and purified water,
an open top chamber (or baffle device) located against the bottom of the tank and having generally vertical walls so as not to conduct upwardly into a portion of the volume of sewage below; We provide an apparatus for carrying out a method according to the second aspect of the invention, characterized in that the apparatus is typically constructed according to the first aspect of the invention.

The method and apparatus according to the second aspect of the invention are characterized in that the disturbance is primarily limited to the deenergization chamber and the open-topped chamber, and that there is a gap between the clean water and the waste water containing aerobic microorganisms. ) can operate away from the boundary. In this way, the water drawn or drained from the tank can be kept generally clean.

The method and apparatus according to the invention will now be described by way of example with reference to the accompanying drawings, in which: FIG.

The drawings are not to scale.

Referring to FIG. 1, the tank 2 is located in the central well 6
It has a floor 4 that slopes inward at a gentle angle toward the floor. A centrally located, vertically arranged and downwardly extending tubular baffle member or baffle 8 is supported (by means not shown) on the top of the tank 2, the baffle member at its lower end extending downwardly from the floor 4 of the tank 2. It has a skirt 10 that widens in the direction of. When the tank is operated to biochemically treat and purify sewage or other aquatic waste having a biochemical oxygen demand, the upper annular portion or layer 16 of the clean water flows between the deflector 8 and the skirt 10. Can be placed at the top. In the remainder of the tank, a biochemical (i.e. bacterial) treatment zone 14 is created in two adjacent zones 14a and 14b (zone 14a being defined by the deflector 8 and the skirt 10). At the top of the tank 2 is a generally circular weir 12 over which the clean liquid from said layer 16 flows and is discharged from the tank 2. The clean water layer 16 is formed due to the tendency of aerobic microorganisms in sewage or other wastewater, typically in the form of activated sludge, to settle out. Typically, the activated sludge is a naturally occurring component of the sewage, but if desired the sewage can be mixed with activated sludge obtained from conventional municipal or other activated sludge wastewater treatment methods. I can do it. Heavy or coarse solids in the sewage tend to sink to the floor 4 of the tank 2 and into the well 6 from which the valve 20 is opened and, if necessary, a suitable suction device (not shown) is used. and can sometimes be sucked out via pipe 18.

If desired, the floor of tank 2 can be fitted with a scraper (not shown) to collect solids on bed 4 and pump them to well 6. Such scrapers are well known in the art and will not be described here.

Near the bottom of tank 2 in biochemical reaction zone 14, the inlets to two pipes 22 are located. Typically the two inlets are diametrically opposed to each other. Each pipe has its own valve 24
and terminates in a dedicated sewage pump 26. Each pipe 22 is associated with an inlet pipe 21 for incoming wastewater for treatment. Each pipe 21
communicates with each pipe 22 downstream of the valve 24. A stop valve 23 is located in each pipe 21. The outlet of each pump 26 communicates with a line 32 which terminates in an injection nozzle 34 located within the liquid surrounded by the baffle member 8 and at a relatively short distance below the surface 46 of the liquid. Each pipe 32 has a bench lily 28. Each bench lily 28 has an inlet 30 for oxygen.

Each injection nozzle 34 is located inside a generally tubular, open-ended chamber 36 . 36 rooms each
is positioned generally vertically within the liquid surrounded by the deflector 8 and the skirt 10. Each room 3
6 includes a top portion 38 that converges toward an intermediate generally cylindrical hollow portion 40 . Said part 4
0 terminates in an open deceleration section 42, the expansion of which is directed away from the nozzle 34. Typically, angle a shown in FIG. 2 is 10 degrees and angle b shown in FIG. 2 is 4 degrees. Each room 3
6 is supported by an adjustable support rod 44. This rod is adjustable to submerge the top of the chamber 36 a selected distance below the liquid level 46. Typically this distance is on the order of 15 cm.

In operation, the water-soluble suspended active sludge is drawn from the lower part of the biochemical reaction zone 14 and passes through the pipe 22 where it is mixed with the wastewater to be treated coming from the pipe 21. The mixture of activated sludge suspension and incoming wastewater formed in each pipe 22 is then pressurized by each pump 26.

Typically, the pressure is raised to a value in the range of 1.5 to 4 absolute pressures. Each stream of pressurized liquid then flows through each bench lily 28 causing a stream of oxygen to be drawn into the liquid at its perturbation. The disturbance is caused by the throat of the bench lily. In this way, oxygen bubbles are formed in each pressurized stream of liquid. Some of the introduced oxygen dissolves, but this is generally only a small percentage. Typically 70-90% of the oxygen is not dissolved and is carried away by the pressurized stream as undissolved bubbles.
The proportion of oxygen added to the pressurized liquid may be greater than or equal to the amount required to saturate the flow with undissolved oxygen at the operating pressure.

It is important that the undissolved gas remains in the form of diffused bubbles and does not combine to create a slow flow or raise the liquid level so as to form a stratified gas phase; Both conditions ensure that undissolved gases are not mixed into the liquid in tank 2 in such a form that they can easily dissolve or be consumed. In order to ensure that sluggish flow or the aforementioned stratification does not occur, the velocity of each pressurized fluid must be set to a certain limited value (sometimes known as the slug flow value - the slug flow rate) or It turns out we need to do more. This limit value can be determined empirically for various devices and should be related to the size range of the gas bubbles involved. however,
Oxygen-enriched air may be used instead if desired. However, nitrogen mixed with oxygen,
It is generally preferred to minimize the amount of other gases. Therefore, it is not preferable to use air with a high oxygen concentration that contains less than 65% oxygen by volume.

The pressurized liquid oxygenated stream is connected to line 32.
through the injection, i.e., expansion nozzle 34 into the chamber 3.
Enter 6. The nozzle has a generally truncated shape with an outlet smaller than an inlet. Each nozzle jets out a mixture of liquid and gas to promote mixing and
The injection or expansion nozzle then creates a disturbance that reduces the size of the oxygen bubbles.

This facilitates the dissolution of the oxygen bubbles so that typically about 95% of the added oxygen is dissolved upstream of the outlet of chamber 36.

The flow of the liquid and gas mixture into the converging portion 38 of each chamber 36 directs the flow of water containing activated sludge from the portion containing the liquid level 46 and surrounded by the deflection member 8 to the converging portion 38 of each chamber 36. Suction inside. Typically, the aspirated liquid flow rate is three to seven times greater than the pressurized liquid flow rate through the nozzle 34. In the biochemical reaction, i.e. in the treatment zone 14, the microorganisms absorb dissolved oxygen;
The concentration of dissolved oxygen in the aspirated liquid stream is much thinner than the oxygen concentration in the oxygenated, pressurized stream introduced into chamber 36 via nozzle 34. As a result, undissolved oxygen bubbles of oxygen entering the cylindrical portion of each chamber 36 dissolve proportionately as they reach the lowermost enlarged portion 42. In this manner, the flow rate of oxygen added to the bench lily 28 is such that it is greater than or equal to that necessary to saturate the pressurized flow without leaving a significant portion of it undissolved after exiting the chamber 36. You can choose.

The cylindrical portion 40 of each chamber 36 typically has a convergent portion 38 so that the aspirated liquid flow mixes well with the liquid introduced into each chamber via the nozzle 34.
It is three times as long. The flared portion 42 is configured to slow the flow of mixed liquid through the chamber 36. Typically, the flared portion 42 is longer than the portion 40 described above. Typically, the liquid stream or jet exiting each nozzle 34 has a velocity on the order of 3-12 meters per second, and the liquid exiting the outlet end of the deceleration section 42 of each chamber 36 has a velocity of 0.75 meters per second.
It is about 1 meter or less, and generally 1 meter or less per second. This exit velocity exceeds the final foam rise velocity.

Thus, undissolved bubbles of oxygen are not buoyant enough to rise against the downward flow of liquid through chamber 36 and are therefore buoyant enough to be lifted by the liquid exiting the chamber. The chamber is then cleaned. Typically, up to 5% by volume of the oxygen added through inlet 30 remains undissolved.

The purpose of oxygenating the liquid in the biochemical reaction zone 14 is to address the respiration needs of activated microorganisms that destroy unwanted organic contaminants in the incoming wastewater. The overall oxygen requirement of the wastewater can be measured in terms of biochemical oxygen demand, and the oxygen treatment rate can be selected to meet this demand by ensuring that the concentration of dissolved oxygen within reaction zone 14 is maintained.

In order to enable proper biochemical treatment, it is preferable to maintain a relatively large proportion of the activated sludge in suspension in the tank 2. In other words, the amount 16 of clean liquid in the tank is limited. In this way, it is preferable to circulate the liquid to some extent so that sufficient purification can be performed within the tank 2. The flow of liquid leaving chamber 36 can provide such circulation below skirt 10. This means that the liquid flow described above is
This occurs because it reverses at the bottom 4 and rises towards the liquid surrounded by the skirt 10. The entire apparatus is arranged in such a way that the liquid leaving the chamber 36 does not have sufficient inertia to cause disturbance in the zone 14, allowing cleaning to take place without disturbing the settling of the sludge.

Each chamber 36 is coated with a baffle plate 50 to reduce the inertia of liquid exiting its outlet.

Also, the liquid flows steadily from the upper part of the liquid inside the deflector 8 to the mixing chamber 36 . This flow causes the necessary circulation or movement within the liquid which separates the baffle member 8 from the clean liquid by its skirt 10.

The aforementioned circulation of liquid in both the upper and lower parts of the tank seeks to achieve a uniform distribution of the activated sludge throughout the biochemical treatment compartment 14.

Preferably, the chamber 36 is located toward the central portion of the wastewater surrounded by the deflector 8 and the skirt 10, and at a sufficient distance from said deflector and skirt. This arrangement ensures that the largely undissolved foam leaving the chamber 36 is then carried to the area of the tank 2 where it rises into the clean liquid portion 16. For example, solid objects of sludge can adhere to the foam and rise to the level of the tank 2. It is preferable to ensure that the solid objects of the sludge or fats and oils rising to the liquid level in this way are retained within the deflecting member 8. In this regard, the skirt 10 collects and directs bubbles into the liquid surrounded by the deflector 8. Any solid matter or fat that rises to the liquid level is disturbed from the liquid level by the circulation effect created by the jetting action of the liquid exiting the nozzle 34 and drawing a stream of liquid from the liquid level 46 into the chamber 36. Typically, in operation, in the illustrated plant, wastewater flows continuously through pipe 21 and is continuously purified. in this way,
Clean water generally continuously overflows the weir 12 and is discharged to the outside or further treated.

Oxygen treatment need not be continuous. If desired, a dissolved oxygen meter is located in the biochemical processing compartment 14 at a location that is not directly impinged by the flow of liquid exiting the chamber 36, and the injected oxygen measures the detected concentration of dissolved oxygen. Once the level drops below a selected level (eg, 1 ppm), oxygen can continue to be supplied until the level returns to, eg, 3 ppm. Typically, the oxygen supply is provided through each oxygen pipe 30.
Automatic control can be provided by providing a dissolved oxygen meter to generate signals to appropriately open and close automatic (eg, solenoid-operated) valves (not shown) located in the oxygen tank.

Typically, at least one pressurized stream of liquid comprising waste water and suspended sludge is directed through nozzle 3.
4 and chamber 36 to the reaction zone 14 continuously. If desired, other similar streams may be passed only during oxygen addition. In this way, the dissolved oxygen meter closes the valve (not shown) in the oxygen pipe 30 and simultaneously closes the valve (not shown) in the oxygen pipe 30.
6 can be arranged to generate a signal that interrupts one of them.

The flow rate of liquid recycled from reaction zone 14 is typically selected to be many times greater than the flow rate of incoming wastewater to mix with the liquid. The relative flow rate of recirculation typically required will vary depending on the biochemical oxygen demand of the incoming wastewater. In general, the greater the biochemical oxygen demand, the more
It is necessary to increase the ratio of the recirculation flow rate to the inflow rate of the wastewater to be treated. Typically this ratio is on the order of 10-20:1. However, the oxygen that may be added to the recirculating stream is sufficient to not only obtain a good level of dissolved oxygen in that stream, but also to oxygenate the liquid introduced into chamber 36 by the action of injector 34. This should be kept in mind. This will increase the effective recirculation flow rate.

If desired, more than one mixing chamber 36 and associated nozzle 34 may be provided. For example, four chambers and nozzles can be provided in a two-row x two arrangement.

The sewage treatment plant shown in Figure 3 is generally the same as that shown in Figure 1 with two differences. The first difference is that the baffle plate 50 in the plant shown in FIG. 1 is omitted. A second difference is that the plant shown in FIG. 3 has a chamber 52 seated on the floor 4 of the tank 2.

The purpose of said chamber 52 is to keep the circulation of liquid, or turbulence, caused by the outflow of fluid from chamber 36 into zone 14b relatively away from the boundary between zone 14b and the layer of clean water 16 above it. It is. Chamber 2 has an overall vertical arrangement and is open at the top.
Extending upwardly through zone 14b to zone 14a and terminating below chamber 36, skirt 10
It extends into the sewage water inside. Said chamber 52 is in coaxial relationship with the baffle member, chamber 8 and skirt 10. However, it is narrower than chamber 8 and has a mouth wider than necessary for the purpose of receiving the flow of liquid exiting chamber 36. The chamber 52 may be generally tubular or cubic. In operation, most of the liquid exiting chamber 36 and flowing generally downwardly and vertically is deflected generally vertically upwardly. However, in reality, without the vertical walls 54 of the chamber 52, the liquid would be separated from the clean water layer 16 and the layer 14.
It has been found that some portion of the liquid is deflected upwards by a significant horizontal velocity component that carries it upwards to the boundary with b. Since the liquid contains suspended solid matter, if it were to reach the boundary it would carry the suspended solid matter into the clean water, rendering the cleaning action insufficient. However, the vertical walls 54 of the chamber 52 provide a barrier or deflection means that prevents the deflection of liquid towards the boundary by deflecting the liquid flowing towards the boundary towards the area 14a. In this way, the deflection of the liquid from the bottom of the tank 2 does not impede the purifying action of the waste water.

After being deflected from the bottom 4 of the tank 2, the waste water enters the chamber 36.
Significant disturbance occurs in said area 14a as a result of the flow of wastewater into and out of said area 14a. In this way, some liquid will flow from zone 14a to zone b outside the top-open chamber 52, but this downward flow will not interfere with the cleaning action of the waste water.

[Brief explanation of the drawing]

1 is a schematic side view, partially in section, of a sewage treatment plant embodying the invention; FIG. 2 is a schematic side view, partially in section, of a portion of the apparatus shown in FIG. 1; FIG. 3 is a schematic side view, partially in section, of another wastewater treatment plant embodying the present invention. In the figure, 2...tank, 4...floor, 6...well,
8... deflection member, 10... skirt, 12... weir, 1
4... Reaction zone, 16... Clean water layer, 21... Inlet pipe, 22... Pipe, 24... Valve, 26... Pump,
28... Bench lily, 34... Injection nozzle, 36...
Chamber, 42... Reduction portion, 44... Support rod, 46... Liquid level, 50... Deflector plate, 52... Chamber, 54... Vertical wall.

Claims (1)

[Claims] 1. A method for dissolving a gas in a liquid in which the gas is slightly soluble, including the step of extracting a liquid flow from the liquid, pressurizing the flow using a pump, and the step of pressurizing the flow with a pump, in which only part of the oxygen is dissolved. introducing oxygen into the pressurized stream such that dissolved and undissolved oxygen is carried into the stream in the form of bubbles; and introducing the stream into an open-ended chamber immersed in the liquid. the flow directing a flow of liquid into the chamber from outside the chamber, the flow and the liquid introduced into the chamber being mixed, such that the mixed flow of liquid is directed from an outlet of the chamber; A method of dissolving a gas in a liquid characterized by a decrease in velocity upstream of the point of discharge. 2. In the method according to claim 1, the chamber is generally cylindrical and has an upstream portion that converges toward an intermediate portion, and a downstream portion that extends from the intermediate portion. A method of dissolving a gas in a liquid characterized by: 3. A method according to claim 1 or 2, characterized in that the stream is introduced into the chamber in jets via at least one nozzle. 4. A method according to claim 2 or 3, characterized in that the nozzle is located in the upstream part of the chamber. 5. In the method according to any one of claims 1 to 4, at least the inlet end of the chamber is in a tank where wastewater is purified and biochemically treated. A method for dissolving gases in a liquid, characterized in that the flow is taken from the aqueous liquid containing activated sludge in a tank. 6. The method of claim 5, wherein at least the inlet of the chamber is located within an aqueous liquid containing aerobic microorganisms involved in the biochemical treatment of sewage suspended in the upper part of the tank; A method for dissolving gas in a liquid, characterized in that the aqueous liquid is separated from the clean liquid in a tank by means of a deenergization box or a suitable buffling device or both. 7. A method according to claim 5 or claim 6, characterized in that the incoming wastewater for treatment is mixed with the stream before being pressurized. 8. A method according to any one of claims 5 to 7, in which undissolved gas bubbles swept from the chamber are prevented from rising into the clean water. A method for dissolving gas in a liquid, characterized in that one or more buttfuls are arranged in the tank. 9. A method according to any one of claims 1 to 8, wherein the inlet of the chamber is located near the surface of the aqueous liquid, whereby:
A method for dissolving a gas in a liquid, characterized in that the liquid flows from the liquid surface into the chamber. 10. A method according to any one of claims 1 to 9, in which a buffer is provided outside the outlet of the chamber or each chamber so as to reduce the inertia of the liquid leaving the chamber. A method of dissolving gases in a liquid, characterized in that they are located in close proximity to each other. 11. A method according to any one of claims 5 to 10, in which the flow is introduced into the chamber at a speed in the range from 3 to 12 meters per second, and the final foam rise rate is A method for dissolving a gas in a liquid, characterized in that it leaves said chamber at an exceedingly high velocity. 12 A device for dissolving a gas in a liquid, a device for extracting and pressurizing a flow of liquid from a container containing the liquid, a device for introducing gas into the flow, and a device disposed within the container and immersed in the liquid. an open-ended chamber, the outlet of which is located adjacent to or within the chamber and at least one nozzle in communication with the outlet end of the ejection device; Apparatus for dissolving gas in a liquid, characterized in that it has an upstream section, an intermediate mixing section and a downstream deceleration section for producing a flow of liquid into the chamber from inside but outside the chamber. 13. A method of treating sewage or other aquatic wastes having a biochemical oxygen demand, in which suspended aerobic microorganisms which take part in the biochemical treatment of the sewage are placed in a tank having a deenergization chamber in the upper area. containing lower sewage; upper sewage within the energy reduction chamber and above the lower sewage; and a step of building up purified water with at least an upper portion surrounding the energy reduction chamber; removing sewage from the lower area of the tank; removing the stream, combining the extracted stream with the incoming wastewater stream, and pressurizing the combined stream; only some oxygen is dissolved, and the undissolved oxygen is in the form of bubbles during the pressurization. introducing oxygen into the pressurized stream such that it is carried in the pressurized stream; introducing the stream into a cylindrical member at substantially the open end, the member being Placed in the room,
thereby causing a flow of liquid to flow from the damping chamber into the open-ended member and mixing this flow with the pressurized flow; reducing the velocity of liquid exiting the tubular member by providing in the member and preventing liquid exiting the tubular member from being deflected into purified water by the walls of a second top-open chamber; A method of treating sewage or other aqueous waste comprising the step of admitting liquid exiting said tubular member downwardly into said second top-open chamber disposed relative to the bottom of said tank. . 14. A method according to claim 13, characterized in that the top-open chamber extends from or near the bottom of the tank to the deenergization chamber. How to process things. 15. In installations for the treatment of sewage or other aquatic wastes with a biochemical oxygen demand, a tank with a deenergization chamber in the upper area, which carries a suspended aerobic system which takes part in the biochemical treatment of the sewage. a tank having therein a lower sewage containing microorganisms, an upper sewage within the energy reduction chamber and above the lower sewage, and purified water at least in an upper portion surrounding the energy reduction chamber; and purified water. removing a stream of waste water from an outlet of clean water from the tank and a lower area of the tank, combining the extracted stream with the incoming stream of waste water;
a pump for thus forming a combined pressurized stream; an inlet for introducing oxygen into said combined pressurized stream; and a pump for introducing said combined pressurized stream into a generally cylindrical member at an open end. an outlet nozzle capable of discharging flow, the member being disposed within the deenergization chamber and having an upstream section, an intermediate mixing section, and a downstream deceleration section; an outlet nozzle, the upstream portion being adapted to direct a flow of sewage from the deenergization chamber into the tubular member during use, and a second open-ended top chamber; positioned with respect to the bottom of the tank and the outlet of the downstream reduction section of the tubular member, and secondly to prevent liquid exiting the tubular member from being deflected into purified water during use. Apparatus for treating sewage or other aqueous waste comprising a second open-ended top chamber having generally vertical walls. 16. The apparatus of claim 15, wherein the top-open chamber extends from or near the bottom of the tank to the deenergization chamber. A device that processes things.