JPS63178886A - Method and device for flotation - Google Patents

Abstract

PURPOSE:To permit efficient execution of a flotation treatment with high accuracy to various kinds of waste liquids by generating finely dispersed bubbles and deposited bubbles in and at arbitrary amt. and ratios in the waste liquid in a flotation tank. CONSTITUTION:Gas and liquid is press-fed to a cyclone 22 where the gas is dispersed and dissolved in the liquid and light fluid and heavy fluid are separated by centrifugal force. The light fluid, i.e., the liquid contg. the excess gas is drawn out of an overflow port 23 of the cyclone and is passed in an injector 29 so that the gas is sucked into the injector 29 by the suction force corresponding to the kinetic energy of the fluid passing in the injector 29. The liquid is further added to the fluid flowing out of the injector 29 so that the liquid regresses to the injector 29. The heavy fluid, i.e., the liquid which contains an arbitrary ratio of the finely dispersed bubbles and in which an arbitrary ratio of the gas is dissolved is drawn out of an underflow port 24 and is introduced into the flotation tank 6 where the finely dispersed bubbles and deposited bubbles are generated in and at an arbitrary amt. and ratio in the waste liquid. The waste water is thus treated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for flotation separation of wastewater that utilizes both dispersed bubbles and precipitated bubbles, and a flotation separation device used in the method. The present invention can be applied not only to general wastewater treatment but also to flotation separation treatment of various liquids, such as sludge concentration treatment. Furthermore, the gas used in the present invention does not necessarily have to be air; for example, nitrogen-rich grade gas (the gas remaining after enzymes are selectively extracted from air) can also be used.

[Prior Art] Generally used flotation separation treatment methods and devices for wastewater include (a) pressurized flotation separation methods and devices that utilize precipitated bubbles, and (b) conventional methods and devices that primarily utilize dispersed bubbles. This is a pressure flotation separation method and device. In addition to this, electrolytic flotation separation methods and
Although flotation separation processing and devices using devices and aeration tubes are known, these methods and devices are limited to special uses.

(a) Pressure flotation separation method/apparatus Water and air are retained in a pressure vessel, the air is dissolved in water under pressure while exhausting excess air, and this dissolved liquid is extracted to obtain the flotation fraction l! Introduced into iIM wastewater. Dissolved air becomes bubbles under atmospheric pressure, and impurities (
Since the target component to be removed is precipitated and attached to the agglomerate, the impurities are floated and separated by the buoyancy of the precipitated bubbles. That is, according to this method, impurities in wastewater are separated mainly by the adhesion action of precipitated bubbles. Although it depends on conditions such as pressure and temperature, generally according to this method, the amount of precipitated bubbles is 2 to 3% by normal volume based on water. Further, according to this method, air bubbles are precipitated in both aggregated impurities and non-agglomerated impurities, so the temperature is as high as 88 degrees.

(b) Atmospheric pressure flotation separation method/equipment Air is introduced into water and passed through a static mixer to create dispersed air bubbles in the water, and the water containing these dispersed air bubbles is mixed with wastewater, and then polymer coagulation occurs. The impurities are aggregated by adding the agent. At this time, the dispersed air bubbles present in the wastewater are trapped in the coagulating impurities, and the impurities are floated and separated by the buoyancy of the dispersed air bubbles.

That is, according to this method, impurities in wastewater are separated mainly by the enclosing action (enclosing action) of dispersed bubbles.

Generally, according to this method, the amount of dispersed bubbles is 10 to 30% of the normal volume of water, and since the amount of bubbles is larger than that in the pressure flotation method, the flotation rate is faster.

Furthermore, the apparatus of this method is relatively smaller and simpler than the apparatus of the previous method.

[Problems to be Solved by the Invention] According to the pressure flotation method, there are problems in that the flotation speed is slow because the amount of bubbles is relatively small, and a large flotation tank is required. In addition, a large pressurized tank and a device to control the level within the tank are required, and the piping becomes complicated, making the entire device larger, increasing the installation cost, and handling the operation and maintenance of the device. The problem is that it becomes complicated.

According to the normal pressure flotation separation method, the entrapment effect of dispersed bubbles becomes difficult for impurities that have already been aggregated by the polymer flocculant and impurities that do not (or are difficult to aggregate) by the polymer flocculant. As a result, there is a problem in that the accuracy of impurity separation is inferior to that of the pressure flotation separation method. Furthermore, as long as dispersed bubbles are created by mechanical operations, it is inevitable that large-diameter bubbles will be generated in the liquid. Such coarse bubbles (for example, about 100 μm or more) have a stronger stirring action than adhesion or entrapment action, and are thought to be one of the factors that impairs separation accuracy.

[Purpose of the Invention] ° The inventor of the present application has conducted various tests on each of these devices, taking into account the advantages and disadvantages of the conventional flotation separation methods and devices, and has found the following (a) to (c). )
We have come to confirm the facts shown below.

(a) When flotation separation is performed using both precipitated bubbles and dispersed bubbles, the separation speed tends to increase and the separation accuracy also tends to increase.

(b) The effectiveness of both bubbles differs depending on the type of wastewater and treatment target level. For example, for oil-containing wastewater from an oil refinery, it is better to increase the number of precipitated bubbles, and for wastewater from a cafeteria, it is better to increase the number of dispersed bubbles to obtain better results.

(c) Removal of coarse bubbles in the dispersed bubbles improves separation accuracy.

Therefore, the present invention provides a flotation separation method that can effectively treat various wastewaters by generating dispersed bubbles and precipitated bubbles in arbitrary amounts and ratios in wastewater, and a flotation separation method that can be used effectively for this method. The purpose is to provide a flotation separation device.

[Means for Solving the Problems] The flotation separation method of the present invention involves pumping gas and liquid into a cyclone, stirring and retaining the fluid within the cyclone, dispersing and dissolving the gas in the liquid, and applying centrifugal force. A light fluid (a fluid with a small apparent specific gravity) and a heavy liquid (a fluid with a large apparent specific gravity) are separated by using The gas is extracted from the overflow port of the cyclone and passed through the injector, and the gas is sucked into the injector using a suction force corresponding to the kinetic energy of the fluid passing through the injector. The heavy liquid, that is, the liquid containing a desired proportion of finely dispersed bubbles and a desired proportion of gas dissolved therein, is extracted from the underflow port of the cyclone, and the fluid is removed from the surface of the cyclone.
i11N! It is characterized by treating wastewater by introducing fine dispersed bubbles and precipitated bubbles into the wastewater in arbitrary amounts and proportions.

Furthermore, the flotation separation device of the present invention includes a pump that pumps gas and liquid under pressure, and internally stirs and stagnates the gas and liquid supplied from the pump to disperse and dissolve the gas in the liquid. (Fluid with small apparent specific gravity)
and a cyclone that separates a heavy liquid (a fluid with a large apparent specific gravity) from a light fluid extracted from the overflow port of the cyclone, that is, a liquid containing excess gas (coarse dispersed bubbles and surplus fine dispersed bubbles). The injector is connected to the suction port of the pump and the injector is connected to the suction port of the pump, and the injector is connected to the suction port of the pump. The tank is characterized by comprising a floating outside sm which is connected to the underflow port of the cyclone and which sends a heavy liquid, that is, a solution containing fine dispersed bubbles, into the tank.

[Function] The liquid extracted from the flotation tank is sucked together with gas [
1 to the pump. The gas is pulverized inside the pump, dispersed in the liquid, and partially dissolved in the liquid. The fluid discharged from the pump flows into the cyclone, and the fluid is stirred by rotational movement within the cyclone, and the gas is further dissolved into the liquid by stirring and retention. Within the cyclone, a large amount of liquid containing more undissolved gas (liquid containing coarse dispersed bubbles and surplus fine dispersed bubbles) is concentrated in the center of the cyclone by centrifugal force. The liquid containing more undissolved gas is extracted from the overflow port of the cyclone, supplied to the injector, and passes through the injector toward the outlet. At this time, a suitable amount of gas is sucked into the injector by a suction force depending on the kinetic energy of the fluid passing through the injector, and the gas is dispersed in the fluid. The fluid that has passed through the injector enters the suction port of the pump together with the liquid that has been drawn out from the flotation tank, is compressed again, and is sent to the cyclone. That is, a liquid containing a larger amount of undissolved gas is circulated between the cyclone injector and the pump, and the injector self-controls the intake air amount according to the proportion of dispersed bubbles contained in this fluid. On the other hand, the dissolved liquid in the cyclone containing fine dispersed air bubbles is extracted from the underflow port and introduced into the wastewater in the flotation tank. The gas dissolved in the liquid becomes precipitated bubbles in the wastewater under atmospheric pressure, so impurities, etc. in the wastewater can be effectively removed in a short time and with high precision due to the entrapping effect of the dispersed bubbles and the adhesion effect of the precipitated bubbles. Separated by flotation.

[Embodiment] An embodiment of the present invention will be described with reference to FIGS. 1-'f and 4.

FIG. 1 is a schematic structural diagram showing a flotation separation device 1 according to this embodiment. 2 in the figure is a conditional device to which raw wastewater is supplied, and this device 2 is provided with an agitator 3. Raw wastewater is conditionally pretreated in device 2 (e.g., aeration,
Screening, chemical injection, etc.), wastewater (water to be treated) enters the pipe P1 from the population 4, and is floated and separated via the T pipe 5 [6
is configured to be sent to the auxiliary Wt 6a. A rotating vane type scum skimmer 7 is provided at the upper part of the flotation separation tank 6, so that impurities floating on the surface of the wastewater W stored in the tank can be scraped out of the tank. 1 floating point again! An outlet 8 of the treated water is connected to the lower part of the I-tube 6 by piping, and the outlet P3 is connected to a suction port 11 of a pump 10 via a T-pipe 9. Therefore floating fraction! Treated water in 114ft6 is pumped to pump 10
will be supplied to

Next, the pump 10 is provided to disperse and dissolve air as a gas into water as a liquid, and to pump these fluids to a cyclone 22, which will be described later. pump 10
may be a normal centrifugal pump (for example, a single-side suction horizontal non-self-contained pump with a simple, inexpensive, and easy-to-handle structure), but
In general, in a normal centrifugal pump, if the proportion of gas in the inflowing fluid becomes large, vibrations, abnormal noises, abnormal wear of the rotating blades, etc. may occur, and the fluid may not be able to be discharged or the discharge may become intermittent. This may cause inconveniences such as The inventors of the present invention believe that the cause of such inconvenience lies in the shape of the fluid passage in the impeller section, and further confirmed that the cause is that the cross-sectional area of the fluid passage is larger on the outlet side than on the artificial side. Therefore, in this embodiment, as will be described later, a pump having a structure that can pump more gas together with liquid is used to further enhance the effectiveness of the entire apparatus.

Reference numeral 12 shown in FIG. 2(a) is an impeller body composed of an upper plate 14 having a post 14a to which a drive shaft 13 is attached, and a plurality of blades 15 provided on one side of the upper plate 14. be. And the blade 1 of the impeller body 12
5 includes a disk-shaped side plate 1 with a hole 16a formed in the center.
6 is fixed to the impeller portion 17.

As shown in FIG. 2(a), the blades 15 have a claw-shaped cross-sectional shape curved into an arc, and each blade 15, the side surface of the upper plate 14, and the inner surface of the side plate 16 form a plurality of blades. A fluid passageway 18 is defined. Unlike the fluid passage in a normal centrifugal pump, this fluid passage 18 is
As shown, the cross-sectional area on the elliptical inlet 19 side is larger, and the cross-sectional area on the elliptical outlet 20 side is smaller, and the wall surface has a smooth shape with no corners.

However, depending on the manufacturing cost and other considerations, the cross-sectional shape of the fluid passage 18 may be a rectangular shape having corners. Further, both cross-sectional areas are set at the outlet 20 so that the apparent flow velocity of the fluid in the fluid passage 18 (the apparent flow rate of the fluid flowing within a certain period of time is the value obtained by dividing the volume by that time).
It is set depending on the fluid pressure at the pump and the mixing ratio of gas and liquid to be pumped. For example, water 6rr? /h, air 2♂/h
When trying to mix and transfer , if the pressure of the fluid at outlet 2o is 5 kgf/crn', the volume of gas is about 17
5, so the cross-sectional area A on the inlet 19 side and the outlet 2
The cross-sectional area A' on the 0 side can be determined by the following equation.

Next, the discharge port 21 of the pump 10 is connected and communicated with a cyclone 22. The cyclone 22 stirs and stagnates the fluid supplied from the pump 10 under pressure, dissolves and disperses gas in the liquid, and uses centrifugal force to separate light fluid (fluid with a small apparent specific gravity) and heavy fluid (apparent specific gravity). As shown in FIG. 3(a), this cyclone 22 is formed into a substantially truncated conical shape. A pipe P4 led from the discharge port 21 of the pump 1o is tangentially connected to the upper side of the cyclone 22 via a pressure gauge 61. Further, a pipe P5 is connected to and communicates with a circulating fluid outlet 23 as an overfluoroscopic fluid provided in the center of the upper half. When the cyclone 22 is installed vertically as in this embodiment, the pipe P5 connected to the circulating fluid outlet 23 is connected to the cyclone 22.
It is preferable that it not protrude into the inside of the body. A pipe P6 is connected to and communicates with a liquid outlet 24 as an underfluoro, which is provided at the lower end of the cyclone 22 and from which the solution is discharged. Piping P6 has valve v1 and polymer flocculant population 2
5 is provided and communicated with the T-tube 5 via a static mixer 26. Therefore, the dissolved liquid from the cyclone 22 joins the water to be treated in the T pipe 5, and the flotation separation tank 6
The water is guided into the auxiliary tank 6a.

Although the cyclone 22 of this embodiment is vertically installed, the cyclone 22 shown in FIG.
) When the cyclone 28 having the central axis 27 is used in a horizontal position, the pipe P5 for extracting the circulating fluid is preferably made to protrude into the inside of the cyclone 28.

Next, a pipe P5 connected to the circulating fluid outlet 23 of the cyclone 22 is connected to an inlet 30 of the injector 29 via a flow meter 02 and a valve V2. As shown in FIG. 4, the injector 29 is a vibrator-shaped device with a passage in the center through which fluid passes.
The inner diameter is tapered from 30 to the center where the throttle hole 31 is located, and the inner diameter is tapered from the center to the outlet 32. A suction port 33 communicating with the throttle hole 31 is formed on the outer circumferential surface of the central portion, and an inlet port 30 is connected to an outlet port 32.
Gas is sucked in from the suction port 33 by the kinetic energy of the fluid passing toward the suction port 33. Also, a check valve 34 is provided inside the suction port 33,
Fluid flowing from the inlet 30 to the outlet 32 is prevented from being discharged to the outside from the suction port 33. Also, injector 2
A disk-shaped twisted blade 35 is rotatably provided at the inlet 30 of No. 9, which stabilizes the gas suction force and
The gas sucked into the injector 29 can be effectively atomized. In addition, instead of such a disk-shaped twisting blade 35, a propeller-shaped blade with less pressure loss may be provided.

Next, a pipe P7 is connected to the suction port 33 of the injector 29. A valve v3 and a flow meter 03 are connected to the pipe P7, and the gas inlet 33 is open to the atmosphere at a predetermined pressure.

Also, a pipe P8 connected to the outlet 32 of the injector 29
is inserted into the T-pipe 9 connected to the suction port 11 of the pump 10 from the other open end. Therefore, the fluid extracted from the circulating fluid outlet 23 of the cyclone 22 takes in air with the injector 29, and then flows through the T-pipe 9 with a floating fraction of 1
IIW! ! It joins with the water in 6 and is sucked into the pump 10.

Next, a method for flotation separation of waste liquid using the apparatus configured as described above will be described.

The pump 10 is driven by a drive means (not shown) to cause the pump 10 to suck air and water in the floating fraction MM6. The liquid and gas sucked into the impeller portion 17 are pressurized while moving through the fluid passage 18 having a smooth shape. The fluid passage 18 of the impeller part 17 in the pump 10 of this embodiment is as follows:
The cross-sectional area on the population 19 side through which the fluid before compression passes is large;
This is done by reducing the cross-sectional area on the outlet 20 side through which the compressed fluid passes. Therefore, when a liquid and a gas, which is a compressible fluid, are pumped together, from the port 19 in the fluid passage 18 to the outlet 20.
The apparent flow rate of the fluid (the apparent flow rate of a fluid flowing within a certain period of time is the volume divided by the time) is constant, so
There are no regions of different pressures within the fluid passageway 18, and no harmful vortices are created within the fluid passageway 18. In particular, in this embodiment, the fluid passage 1
Since the wall surface of 8 has a smooth shape with no corners, the resistance between the wall surface and the fluid is uniform in all parts, and fluid vortices that can wear the wall surface occur in specific parts. There's no fear of it happening. In this way, the gas and liquid grown in the impeller part 17 are smoothly transferred at a constant flow rate without generating vortices in the smooth-shaped fluid passage 18, so that a considerable amount of gas can be pumped together with the liquid. Even in such a case, troubles such as abnormal noises and vibrations will not occur during operation of the bomb 10, and the wall surface of the fluid passage 18 will not be abnormally worn. Then, in the impeller section 17, the sucked gas is pressurized and pulverized into fine pieces, dispersed and mixed in the liquid, and a part of the gas is dissolved in the liquid.

The fluid discharged from the pump 10 flows into the cyclone 22, and this fluid is stirred while vigorously rotating inside the cyclone 22 under pressure, and the gas is further dissolved into the liquid by stirring and retention. In the cyclone 22, the light fluid, that is, the liquid containing more undissolved bubble-like gas, gathers in the center of the cyclone 22 due to centrifugal force. In addition, by combining and increasing the volume, gases that have become dissolved and gases that are coarse from the beginning also gather in the center.

That is, within the cyclone 22, separation of gas and liquid and air valve H (coarse bubbles and fine bubbles 1lII) are performed simultaneously by centrifugal force. On the other hand, a vertical fluid, that is, a liquid containing a certain amount of finely dispersed bubbles and in which gas is dissolved (dissolved liquid)
The liquid moves to the lower half of the cyclone 22 while rotating, and is sent to the valve v1 through the liquid outlet (underfluoro) 24. In this case, the amount of solution coming out of the liquid outlet 24 is kept constant by appropriately adjusting the opening degree of the valve v1, so the pressure in the system of this device including the cyclone 22 is kept constant. There is. Then, the solution containing fine dispersed bubbles that has passed through the valve V1 is stirred by a static mixer 26 after being added with a polymer flocculant from an inlet 25, and is combined with wastewater (pretreated) in a T pipe 5. The floating rate was 111!
6 into the auxiliary M6a. Floating F minute l! II tank 6
Since it is open to atmospheric pressure, the gas dissolved in the liquid becomes precipitated bubbles in the wastewater under atmospheric pressure, adheres to impurities in the wastewater, and floats and separates them. On the other hand, since dispersed air bubbles are trapped in the impurities aggregated by the polymer flocculant, these impurities are also floated and separated. As described above, according to the method of this embodiment, the adhering action of the precipitated bubbles and the enclosing action of the dispersed bubbles have a synergistic effect, and impurities in wastewater are efficiently floated and separated in a short time with high accuracy. The floating impurities are scraped out of the tank by the scum skimmer 7, and the treated water passes through the pipe P2 and is discharged from the outlet 8 to a predetermined position outside.

Next, the water containing more undissolved air bubbles is extracted from the circulating fluid outlet 23 (overfluoro), supplied to the inlet 30 of the injector 29, and passes through the injector 29 toward the outlet 32. To go. At this time, air is sucked into the injector 29 through the suction port 33 by the kinetic energy of the passing fluid. The suction force of air varies depending on the kinetic energy of the passing fluid, that is, the amount of bubbles contained in the fluid. For example, when the fluid extracted from the circulating fluid extraction port 23 contains many bubbles, the kinetic energy of the fluid is small, so the amount of air sucked into the injector 29 is small. Conversely, if the fluid contains almost no air, a large amount of air will be sucked into the injector 29 by a strong suction force corresponding to its kinetic energy. In this way, in the device 1 of this embodiment, the amount of gas suction is self-controlled. The air sucked in by the injector 29 is dispersed in the liquid together with the undissolved gas sent from the cyclone 22, and is atomized in the injector 29 and dispersed and mixed in the liquid. Furthermore, in this embodiment, since the injector 29 is provided with twisting blades 35,
The gas suction condition is stable.

Next, the fluid that has passed through the injector 29 is sent into the T-pipe 9 via the pipe P8. This fluid then merges with the water sent from the floating fraction 111!6 and is sucked into the pump 10.

As described above, the liquid sent from the cyclone 22 to the flotation separation tank 6 contains a predetermined amount of fine dispersed air bubbles, and also dissolves air that becomes precipitated air bubbles under atmospheric pressure. By appropriately adjusting the amount and ratio of dispersed bubbles and precipitated bubbles in the wastewater W in the flotation tank 6 according to the properties of the wastewater W to be flotated, highly accurate and efficient flotation can be carried out in various ways. It can be done on waste liquid. In the embodiment described above, the amount of dispersed bubbles can be increased or decreased by adjusting the amount of suction air of the cyclone 29 by operating the valve v3. In addition, the saturated amount of air dissolved in water is determined by the pressure, and the residence time in the cyclone 22 until saturation is determined is determined by the device system. Cyclone 22 stays in the
All you have to do is determine the capacity. By increasing the amount of circulating water, the discharge pressure of the pump 10 can be lowered.
The amount of precipitated bubbles can also be adjusted.

In this way, in this example, an appropriate amount of water is used with a floating fraction of 111M.
At the same time, a part of the fluid containing more undissolved gas is separated by centrifugal force in the cyclone 22, and this is circulated in the system while being fed into the system. The amount of air taken in is self-controlled by odor = fu29, and the gas is efficiently dispersed and dissolved in the liquid. That is, in the device 1 of this embodiment, since the fluid is circulated, there are many chances of contact between gas and liquid, and since the gas is repeatedly atomized in various places, the contact area of gas and liquid is large, so that the water in the air is The dispersion and dissolution of these substances is extremely efficient. Then, the solution containing dispersed bubbles is extracted from the cyclone 22 and the floating fraction is 1f! T! 6, the flotation separation treatment of wastewater is carried out with high intensity and in a short time using fine dispersed bubbles and precipitated bubbles.

Next, the results of testing the flotation and separation device 1 will be explained using a specific example. 34 kwx 2,90Orpm
An impeller portion 17 having a fluid passage 18 as described above is attached to an ordinary centrifugal pump. The cyclone 22 has a truncated cone shape with a diameter of φ250×φ200 and a height of 13011 mm.
The injector 29 has an inner diameter of about 10 mm at the entrance/exit part, a total length of about 50 mm, and a throttle hole 31.
An inner diameter of approximately 3 mm was used. This injector 2
9, the inflow pressure of the injector 29 is 4.0.
kgf/c rn'・When the same inflow rate is in/min, 1
It has been experimentally confirmed that it is 0 N 17m1n.

Now, we selected hotel chushi waste liquid (waste liquid generated when chusuke is crushed and dehydrated) as the waste liquid to be treated, used air as the gas, and conducted tests by varying the amount of suction air. The results are shown in Table 1 as Example (1). Further, the data for Examples (2) to (6) shown in Table 1 were obtained by setting the amount of waste water to zero and adjusting the flow rate, discharge pressure, etc. of the pump by operating each valve. Also, for comparison,
The results obtained using the conventional equipment under the same conditions are shown in this example (
1) as well as shown in Tables 2 and 3. In Tables 2 and 3, Comparative Example (A) is a device that mainly uses dispersed bubbles as explained in the section [Prior Art 1], and Comparative Example (B) is a device that mainly uses dispersed bubbles as explained in the section [Prior Art]. This is a device that mainly uses precipitation bubbles.

Table 1 Table 2 Table 3 As shown in Examples (2) to (6) in Table 1, according to the apparatus and method of this example, dispersed bubbles and precipitated bubbles can be obtained in arbitrary amounts and ratios. .

Therefore, flotation separation treatment can be carried out in accordance with the properties of the wastewater to be treated.

As can be seen from Table 3, in this example, the residence time of the fluid in the flotation separation tank was 12 minutes, which is the same as in Comparative Example (A). The separation accuracy is higher in Example (1) than in Comparative Example (A). Although Comparative Example (B) requires a considerably longer residence time than Example (1), the flotation separation accuracy is considerably inferior to Example (1) from the analytical values. As described above, according to the present example, it was confirmed that the flotation separation process was considerably high and the accuracy was very excellent, and that it was possible to efficiently perform the effective flotation separation process depending on the type of waste liquid.

[Effects of the Invention] According to the flotation separation method and device according to the present invention, fine dispersed bubbles and precipitated bubbles can be generated in the waste liquid in the float separation tank in arbitrary amounts and ratios.・It has the effect that flotation separation treatment with good particle size can be efficiently performed on various waste liquids using a device with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing one embodiment of the device according to the present invention, FIG. 2(a) is a partially cutaway front view showing the main parts of the pump in the same embodiment, and FIG. 3(a) is a plan view and a front view of the cyclone in the same embodiment, FIG. 3(b) is a diagram showing the horizontal cyclone, and FIG. 4 is a diagram showing the shape of the fluid passage in the pump. FIG. 3 is a cross-sectional view of the injector. 1...Flotation separation device, 6...Flotation fraction li! Kasu, 10
...Pump, 11--Suction port, 22--Cyclone, 23--Circulating fluid outlet as overfluoro,
24-7 Liquid outlet as dafluoro, 28--Cyclone, 29--Injector, 32--Injector outlet, W--Wastewater. Figure 2 (a) (b) Figure 3

Claims (2)

[Claims] (1) Gas and liquid are forced into a cyclone, the fluid is stirred and retained in the cyclone, and the gas is dispersed and dissolved in the liquid, and the centrifugal force is used to create light fluid (fluid with small apparent specific gravity) and heavy fluid ( The light fluid, that is, the liquid containing excess gas (coarse dispersed bubbles and surplus fine dispersed bubbles), is extracted from the overflow port of the cyclone and passed through the injector. The gas is sucked into the injector with a suction force according to the kinetic energy of the fluid passing through the injector, and liquid is added to the fluid flowing out from the injector and returned to the cyclone to form a heavy fluid, that is, fine dispersed bubbles of an arbitrary proportion. A liquid containing dissolved gas in a desired proportion is extracted from the underflow port of the cyclone, and the fluid is introduced into a flotation separation tank to generate fine dispersed bubbles and precipitated bubbles in a desired amount and proportion in the wastewater. A flotation separation method characterized by treating wastewater by (2) A pump that pumps gas and liquid, and the gas and liquid supplied from the pump are stirred and retained inside to disperse and dissolve the gas in the liquid, and centrifugal force is used to disperse and dissolve light fluid (low apparent specific gravity). A cyclone separates heavy fluid (fluid) and heavy fluid (fluid with large apparent specific gravity), and a light fluid, that is, excess gas (
A liquid containing coarse dispersed bubbles and surplus fine dispersed bubbles passes through the pump, and gas is sucked into the pump by a suction force that corresponds to the kinetic energy of the passing fluid, and the fluid outlet is connected to the suction port of the pump. a flotation separation tank that is connected to the suction port of the pump to send liquid to the pump, and is also connected to the underflow port of the cyclone to send heavy fluid, that is, a dissolved liquid containing fine dispersed bubbles, into the tank; A flotation separation device comprising: