JPS63221882A - Method and apparatus for flocculation float-separation - Google Patents

Abstract

PURPOSE:To apply separation treatment to a waste liquid of every kind with high accuracy and high efficiency, by generating fine dispersed air bubbles and precipitation air bubbles in the waste liquid within a float-separation tank in an arbitrary amount and ratio and flocculating components to be removed using an org. polymer flocculant. CONSTITUTION:Fine dispersed air bubbles and precipitation air bubbles are generated in the waste water W, which receives pretreatment such as the injection of chemicals in a reaction tank and sent to the auxiliary tank 6a of a float-separation tank 6, in accordance with the kind of the waste water W by a pump 10 as an air bubble generator. Further, an org. polymer flocculant is added to the waste water from a chemical agent adding port 7 to flocculate components to be removed in the float-separation tank 6 where air bubbles are generated. The air bubbles are enclosed in the components to be removed or precipitated and adhered to the surfaces of the flocculated components to be removed to perform the float-separation of the components to be removed by the buoyancy of the air bubbles. By the synergistic action of the adhesion of precipitation air bubbles and the enclosing of dispersed air bubbles, impurities can be efficiently separated within a short time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for coagulating and flotation separation of wastewater that utilizes both dispersed bubbles and precipitated bubbles and further utilizes an organic polymer flocculant, and a method for use in the method. The present invention, which relates to flocculation and flotation equipment, can be applied not only to general wastewater treatment but also to flocculation and 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 air (the gas remaining after oxygen is 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 methods and devices using devices and air diffusers are known, these methods and devices are limited to special uses.

(a) Pressure flotation separation method/equipment 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 make waste water in the flotation tank. Introduce it inside. The dissolved air turns into bubbles under atmospheric pressure, and precipitates and adheres to aggregates of impurities (components to be removed) in the wastewater, so that 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 the 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. Furthermore, according to this method, bubbles are deposited in both aggregated impurities and non-agglomerated impurities, so separation accuracy is high.

(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 further organic polymer Impurities are aggregated by adding a flocculant. 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, resulting in an increase in the size of the entire device, increased installation costs, and the maintenance of the device's cab. The problem is that it becomes complicated.

According to the normal pressure flotation separation method, the entrapment action of dispersed bubbles is performed for impurities that have already been aggregated by the organic polymer flocculant and impurities that do not (or are difficult to aggregate) by the organic polymer flocculant. As a result, there was a problem that the accuracy of impurity separation was inferior to that of the pressure flotation separation method. Furthermore, as long as dispersed bubbles are created by mechanical operations, it is inevitable that bubbles with large diameters will be generated in the liquid.
It is thought that it is more than m. ) is considered to be one of the factors that deteriorates the one-minute accuracy because the stirring action is stronger than the adhesion action or the enveloping action.

[Purpose of the Invention] The inventor of the present application has conducted various tests on each of the conventional flotation separation methods and devices, taking into consideration the advantages and disadvantages of these 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 types of air bubbles differs depending on the type of wastewater and treatment target level.For example, it is better to use more precipitated air bubbles for oil-containing wastewater from a refinery, and more dispersed air bubbles for wastewater from a restaurant. You'll get better results if you do.

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

Therefore, in the present invention, dispersed bubbles and precipitated bubbles are generated in wastewater at an arbitrary base ratio, and an organic polymer flocculant is added to the wastewater to coagulate the components to be removed. The object of the present invention is to provide a coagulation flotation separation method that can effectively treat various types of wastewater through action, and further to provide an effective coagulation flotation separation device that can be used in the method.

[Means for Solving the Problems] The coagulation flotation separation method of the present invention generates fine dispersed bubbles and precipitated bubbles in arbitrary amounts and ratios in wastewater in a flotation tank, and at the same time generates a high organic content in the wastewater. The method is characterized in that the target component to be removed is aggregated by adding a molecular flocculant, and the bubbles are attached to or included in the aggregated target component to be removed, whereby the target component to be removed is floated and separated. Further, the flocculation floatation S device of the present invention includes a flotation separation tank for treating wastewater,
A bubble generator that generates fine dispersed bubbles and precipitated bubbles in arbitrary amounts and proportions in the wastewater in the flotation separation tank, and a chemical agent for adding an organic polymer flocculant to the wastewater in the flotation separation tank. It is characterized by having an addition port.

[Function] The bubble generator generates fine dispersed bubbles and precipitated bubbles in the wastewater in the flotation tank in an arbitrary amount and ratio according to the properties of the wastewater. Then, an organic polymer flocculant is added to the wastewater through the chemical addition port, and the components to be removed are flocculated in the flotation tank where air bubbles are generated. Since the bubbles are included in the aggregated components to be removed or are deposited and attached to the surface of the aggregated components to be removed, the aggregated components to be removed are floated and separated by the buoyancy of the bubbles.

[Example] An embodiment of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 is a schematic structural diagram showing a coagulation flotation separation device according to this embodiment. 1 in the same figure is 2#e where raw wastewater is supplied.
This reaction tank is equipped with a chemical injection device 2, an agitator 3, a reaction control sensor 4, etc. The raw wastewater supplied to the reaction tank 1 is treated by these devices. The wastewater W (water to be treated) is subjected to pre-treatment such as chemical injection, and the inlet 5 of the wastewater W (water to be treated) also enters the pipe P1 and is sent to the auxiliary tank 6a of the flotation tank 6. Also, a valve V is located in the middle of the pipe Pi.
A chemical addition lower is provided through the flotation tank 6 so that an organic polymer flocculant can be added to the wastewater W fed into the flotation separation tank 6.

A rotating vane type scum skimmer 8 is provided at the upper part of the flotation separation tank 6, and can scrape out impurities that have floated to the surface of the wastewater W stored in the tank to the outside of the tank. In addition, at the bottom of the flotation separation tank 6 there is an outlet 9 for the treated water.
are connected and communicated by piping P2. Further, a pipe P3 is connected to the bottom of the funnel-shaped flotation separation tank 6, and the pipe P3 is connected to a suction pipe 11 of a pump 10 as a bubble generator via a valve v2. . Therefore, the treated water in the flotation tank 6 is supplied to the pump IO.

Next, the pump 10 is provided to generate air bubbles in the waste water W in the flotation tank 6, and disperses and dissolves air in the treated water drawn from the flotation tank 6. The connection structure is such that these fluids can be sent to the auxiliary tank 6a of the flotation separation tank 6 again. This pump 1o may be constructed by modifying 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, the inflow When the proportion of gas in the fluid increases, vibrations, noise,
In addition to causing abnormal wear of the rotating blades, there may be other inconveniences such as inability to discharge fluid or intermittent discharging of the fluid. We thought that the cause of the problem was due to the shape of the fluid passage, and further confirmed that the cross-sectional area of the fluid passage was larger on the outlet side than on the inlet 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.

12 shown in FIG. 2 is a boss 1 to which the drive shaft 13 is attached.
The impeller main body is constituted by a soil base 14 having 4a and a plurality of blades 15 provided on one side of the soil base 14. A disk-shaped side plate 16 having a hole 16a formed in the center is fixed to the blades 15 of the impeller main body 12, and constitutes an impeller portion 17. As shown in FIG. 3(a), the blades 15 have a claw-shaped cross section curved in an arc, and each blade 15 and the soil plate 1
A plurality of fluid passages 1 are formed by the side surfaces of 4 and the inner surface of the side plate 16.
8 are made up. Unlike the fluid passage in a normal centrifugal pump, this fluid passage 18 has a larger cross-sectional area on the elliptical inlet 19 side and a larger cross-sectional area on the elliptical outlet 20 side, as shown in FIG. 3(b). has become smaller, and its walls have a smooth shape with no corners.

However, depending on the manufacturing cost and other circumstances, the cross-sectional shape of the fluid passageway 8 may have corners such as a rectangular shape. The outlet 20 is designed so that the apparent volume of the fluid flowing within a certain period of time (the value obtained by dividing the volume by that time) is constant.
For example, water 6rn'/h, air 2rn'/h, etc.
When trying to mix and transfer '/h, if the fluid pressure at the outlet 20 is 5 Kgf/am', the volume of gas is approximately 1
15, the cross-sectional area A on the inlet 19 side and the cross-sectional area A' on the outlet 20 side can be determined by the following equation.

Next, the casing portion in which the impeller portion 17 is housed will be explained. The outer corner wall 21 of the casing portion has a substantially truncated conical shape, and a disk-shaped flange 22 is provided on the small diameter left end surface.
is fixed. A liquid supply hole 22a is formed in the center of the flange 22, and the supply hole 22a communicates with the suction pipe 11 attached to the center of the inner surface of the flange 22.

The suction tube 11 is installed horizontally at the center of the outer corner wall 21, and a circular wall plate 23 is provided at the open end opposite to the supply hole 22a. The impeller section 17 is rotatably mounted on the wall plate 23 and the open end of the suction tube 11. A lid member 24 is fitted and fixed to the large-diameter opening end of the outer corner 1321 to open the inner space of the outer corner wall 21 into a second
It is divided into a spiral chamber S2. Further, the left end surface of the lid member 24 contacts the outer peripheral edge of the wall plate 23 inside the outer corner wall 21 and rotatably holds the impeller portion 17 between it and the wall plate 23. As shown in FIGS. 2 and 3(a), there is a gap between the outer circumferential portion of the impeller portion 17 and the wall plate 23 and the lid member 24, which gradually expands along the rotational direction of the impeller portion 17. A spiral space is configured as the first spiral chamber S1. The first vortex chamber S1 opens and communicates with the second vortex chamber S2, and the first vortex chamber S1
The fluid energized in step 1 flows tangentially into the second swirl chamber S.
2. A discharge port 25 is provided at the left end of the second volute chamber S2, which has a smaller inner diameter, in a tangential direction to the cylindrical outer corner wall 21. A portion of the fluid that has moved to the left end while rotating in the direction is discharged tangentially to the outside. Further, an extraction pipe 26 is provided through the outer corner wall 21. The opening end of the extraction pipe 26 is provided at a position near the suction pipe 11 provided at the center of the second swirl chamber S2, that is, at the center of rotational movement of the fluid, and away from the discharge port 25. It is configured so that some of the fluid that has collected at that location can be extracted from the room. Also, inside the suction pipe 11 is a small diameter supply pipe 27.
are provided coaxially, and the supply pipe 27 passes through the peripheral wall of the suction pipe 11 and the flange 22 to communicate with the outside.

The pump of this embodiment has the above-mentioned configuration, but when expanded, the space S2' in the part of the second spiral chamber S2 where the outer corner wall 21 is parallel to the central axis C is as shown in FIG. 7(a). It is shaped like this. In other words, since the axial dimension A is constant, Fig. 7(b)
As shown by the arrow in , the fluid is pushed out to a large degree in the direction of the axis C in this space S2', and the centrifugal force tends to be reduced. Therefore, as shown in FIGS. 5, 6, and 8, a pump in which the shape of this space S2° is particularly improved may be used in this embodiment. That is, the length A in the axial direction of the space 52° is maximum at the 0° position in the cross-sectional view shown in FIG. It should be approximately half of , and be 0 at the 360° position. FIG. 8(a) is an expanded perspective view of this space S2', in which both the axial length A and the radial length become shorter along the rotation direction.

Therefore, as shown by the arrow in FIG. 8(b), the fluid is gradually pushed out in the direction of axis C while rotating under the influence of centrifugal force. Therefore, if such a pump is used, a larger centrifugal force can be applied to the fluid in the second vortex chamber S2, so that the fluid in each of the vortex chambers S2 can be roughly and effectively stirred. The pump shown in Fig. 5 is equipped with the extraction pipe 26 and various valves V3 as shown in Fig. 2.
．． Although V4 and the like are not shown, it goes without saying that if this pump is employed as an example, it will have a configuration similar to that shown in FIG. 2. Furthermore, as shown in FIG.
may be provided at two locations 180° apart from each other in the rotational direction. Then, the shape of each part of the spiral chamber S2 near the exit EX is formed as shown in FIG. 8(a). That is, at the 0° position in FIG. 9, the axial and radial dimensions of the part of the spiral chamber S2 near one exit EX are maximum, and decrease along the rotational direction. It becomes O at the 180° position. Swirl chamber S2 near the other exit EX
For the part, the axial and radial dimensions are 180
It is maximum at the position of 36° and decreases along the rotation direction to 36°.
It is 0 at the 0° position. If you do this, the second
Even if the outer diameter of the swirl chamber S2 is made small, the fluid can be efficiently stirred.

In the improved examples of the pump or other structural examples described above with reference to FIGS. 5 to 9, the shape of the fluid passage in the impeller portion is formed in the same manner as in the pump shown in FIG. 3(a). There is. That is, as shown in FIG. 3(b), an elliptical entrance 1
The cross-sectional area on the 9 side is large, and the cross-sectional area on the elliptical exit 20 side is smaller, and the wall has a smooth shape with no corners, but depending on the manufacturing conditions etc. There may be.

Next, an insector 28 is provided outside the outer corner wall 21 to suck in gas using the kinetic energy of the passing fluid. As shown in FIG. 4, the insector 28 is a pipe-shaped device with a passage provided in the center through which fluid passes, and has a tapered shape in which the inner diameter is narrowed from the inlet 29 to the center where the throttle hole 30 is located. It is formed into a tapered shape whose inner diameter increases from the center portion to the outflow port 31. The aperture hole 30 is provided on the outer peripheral surface of the central portion.
A suction port 32 is formed in communication with the suction port 32, and gas is sucked through the suction port 32 by the kinetic energy of the fluid passing from the inflow port 29 toward the outflow port 31. Further, a check valve 33 is provided inside the suction port 32 to prevent fluid flowing from the inflow port 29 toward the outflow port 31 from being discharged from the suction port 32 to the outside. In addition, a disk-shaped twisting blade 3 is provided at the inlet 29 of the insector 28.
4 is rotatably provided to stabilize the gas suction force and to effectively atomize the gas sucked into the injector 28. In addition, instead of such a disk-shaped twisting blade 34, a propeller-shaped blade with less pressure loss may be provided.

Next, the inlet 29 of the insector 28 and the extraction pipe 2
6 by piping via a valve V3, and a pressure gauge 35 is provided in the middle of the piping. The outlet 31 of the insector 28 and the supply pipe 27 are connected by piping. The suction port 32 of the insector 28 is opened to gas at a predetermined pressure via a valve v4 and a flow meter 36. Further, as described above, the suction pipe 1 of the pump 10
1 is connected to the bottom of the floating fraction 111 tank 6, and the impeller section 17 is supplied with treated water in the flotation separation tank 6.

Further, the drive shaft 13 of the impeller section 17 passes through the lid member 24 and is supported by a bearing 37, and its end is operatively connected to the output shaft of the motor M by a flange joint 38.

Next, next to the flotation separation tank 6 is a storage tank 39 that stores the components to be removed that have been scraped off by the scum skimmer 8.
is provided. This storage tank 39 is provided with a chemical inlet, so that the chemical can be added to the sludge in the tank as shown by arrow A1. Also, this storage tank 39
A stirrer 40 is also provided.

Next, a dehydrator 41 is installed next to the storage J139. This dehydrator 41 includes a plurality of rollers 44, 45.
It has an endless door material 42 that is wound around and driven in circulation. The endless P material 42 is sandwiched between a rotatably installed press drum 43 and a plurality of (five in the illustrated example) rollers 44 coaxially provided along the circumferential surface of the press drum 43. It has become. The sludge treated with chemicals in the storage tank 39 is carried on the endless P material 42 and is pressed against the endless furnace material 42 between the pressing drum 43 and the rollers 44. The water contained in the sludge is separated through the endless P material 42 and stored in the lower receiver 146, and the dehydrated sludge that has become cake-like is scraped off by a scraper 47 and falls onto the loading platform of the transport vehicle 48. It is composed of

Next, an embodiment of a method for coagulating flotation and separation of waste water using the apparatus configured as described above will be described.

The pump 10 is driven by the motor M, and the air and water in the flotation separation HIG are sucked into the pump IO.

The liquid and gas sucked into the impeller portion 17 are pressurized while moving through the fluid passage 18 having a smooth shape. Fluid passage 18 of impeller section 17 in pump 10 of this embodiment
The cross-sectional area on the side of the outlet 19 through which the fluid before compression passes is large, and the cross-sectional area on the side of the outlet 20 through which the fluid after compression passes is small, ψ. Therefore, when a liquid and a gas, which is a compressible fluid, are pumped together, the apparent flow rate of the fluid from the port 19 in the fluid passage 18 to the outlet 20 (the apparent volume of the fluid flowing within a certain period of time is Since the resultant value (divided by the pressure) remains constant, no regions with different pressures will occur in the fluid passage 18, and problems such as harmful vortices will not occur within the fluid passage 18.

In particular, in this embodiment, the wall surface of the fluid passage 18 has a smooth shape with no corners, so the resistance between the wall surface and the fluid is uniform in all parts, which may cause the wall surface to wear out. There is also no fear that fluid vortices will occur in specific parts. In this way, the gas and liquid sucked into the impeller section 17 are smoothly transferred at a constant flow rate within the smooth-shaped fluid passage 18 without generating a vortex, so that a considerable amount of gas can be pumped together with the liquid. Even in this case, troubles such as abnormal noise and vibration do not occur during operation of the pump 10, and the wall surface of the fluid passage 18 does not wear abnormally. Then, in the impeller section 17, the sucked gas is pressurized and pulverized into fine pieces, and dispersed and mixed into the liquid. This fluid flows into the first swirl chamber S1 and is stirred, and some of the gases dissolve into the liquid.

This fluid then exits the first volute chamber S1 tangentially and flows into the second volute chamber S2. In the vortex chamber S2, the liquid and the finely dispersed gas rotate violently, and the dissolution of the gas further progresses due to stirring and retention. In the second swirl chamber S2, a large amount of fluid with a relatively low specific gravity, that is, a liquid containing a large amount of undissolved bubble-like gas, gathers in the center of the second swirl chamber S2 due to centrifugal force. Additionally, gases that have become difficult to dissolve due to their association and increased volume, and gases that are coarse from the beginning, also gather in the center. That is, in the second volute chamber S2, centrifugal force separates gas and liquid and creates a gas atmosphere 1Il.
(Coarse bubbles and fine bubbles I!l) are performed simultaneously. On the other hand, a fluid with relatively high specific gravity, that is, a liquid containing a certain amount of fine dispersed bubbles and dissolved gas (dissolved liquid), rotates and moves to the left end of the second #I@chamber S2, It is sent through the discharge port 25 to the valve v5.

In this case, since the amount of solution coming out of the discharge port 25 is kept constant by appropriately adjusting the opening degree of the valve v5, etc., the pressure in the second swirl chamber S2 is kept constant.

Then, the dissolved liquid containing fine dispersed bubbles that has passed through the valve v5 joins the pretreated wastewater to which an organic polymer flocculant has been added from the drug addition lower, and is sent into the auxiliary tank 6a of the flotation tank 6. It will be done. Since the floating fraction lIIMI6 is exposed 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, dispersed air bubbles are trapped in the impurities flocculated by the organic 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. Then, the floating impurities are scraped out of the tank by the scum skimmer 8, and then the moisture is separated by the dehydrator 41, and the impurities are carried out to the outside in the form of a cake. The treated water passes through the pipe P2 and is discharged from the outlet 49 to a predetermined position outside.

Next, the water containing more undissolved air bubbles is removed from the extraction pipe 2.
6 and supplied to the inlet 29 of the injector 2, and passes through the injector 28 toward the outlet 31. At this time, air is sucked into the injector 28 through the suction port 32 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 extraction tube 26 contains many bubbles, the kinetic energy of the fluid is small, so the amount of air sucked into the injector 28 is small. Conversely, if the fluid contains almost no air, a large amount of air will be sucked into the insector 28 due to the strong suction force corresponding to its kinetic energy. In this way, in the pump 10 of this embodiment, the amount of gas suction is self-controlled. The air sucked in by the injector 28 is dispersed in the liquid together with undissolved gas sent from the second swirl chamber S2.
In this insector 28, the particles are made fine and dispersed and mixed in the liquid. Further, in this embodiment, since the injector 28 is provided with the twisted blades 34, the gas suction state is stable.

Next, the fluid that has passed through the injector 28 has a floating fraction of 1 fH.
! The water sent from 6 is combined with the suction pipe 11 of the pump 10.
It is sucked into the air and sent to the impeller section 17 again.

As described above, the liquid sent from the pump 10 to the flotation separation tank 6 contains a predetermined amount of fine dispersed air bubbles, and also has dissolved air that becomes precipitated air bubbles under atmospheric pressure. If the amount and ratio of dispersed bubbles and precipitated bubbles in the wastewater W in the flotation separation tank 6 are adjusted appropriately according to the properties of the wastewater W to be treated, highly accurate and efficient coagulation flotation separation treatment can be performed in various ways. This can be done for waste liquid. In the embodiment described above, by operating the valve v4 to adjust the amount of air sucked into the injector 28, the amount of dispersed bubbles can be increased or decreased. In addition, the saturated dissolution amount of air in water is determined by the pressure, and the residence time until reaching saturation in the second volute chamber S2 is determined as a device system. The capacity of the second swirl chamber S2 may be determined so that the discharge amount discharged in the second swirl chamber S2 remains in the second swirl chamber S2 for the residence time.

Since the discharge pressure of the pump 10 can be lowered by increasing the amount of circulating water, the amount of precipitated bubbles can also be adjusted.

In this embodiment, an appropriate amount of water is extracted from the flotation tank 6 and supplied to the pump 10, and a portion of the fluid containing more undissolved gas is transferred to the second swirl chamber S2 of the pump 10. The gas is separated by centrifugal force, and while being circulated within the system, the injector 28 self-controls the amount of air taken in, thereby efficiently dispersing and dissolving the gas in the liquid. In other words, in the device of this example, 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 the air has a large contact area with water. Dispersion and dissolution are extremely efficient. Then, the dissolved solution containing dispersed bubbles is extracted from the second swirl chamber S2 of the pump 10 and returned to the flotation tank 6, and the fine dispersed bubbles and precipitated bubbles are coagulated with an organic polymer flocculant to perform coagulation flotation separation of wastewater. Processing is performed with high precision and in a short time.

Next, the results of testing the flotation and separation device will be explained using a specific example. An impeller portion 17 having a fluid passage 18 as described above is attached to a water single-suction centrifugal pump having a discharge rate of 0.10 rn'/win and a total loss of g 39 m. The approximately circular female trapezoidal outer corner wall 21 constituting the second spiral chamber S2 is
The inner diameter is φ300×φ25o1 and the length is about 250II11. The injector 28 has an inner diameter of 1
01, the total length is about 50cm, and the inner diameter of the aperture hole 30 is 31cm.
I used something of about 100%. The self-suction air amount of this injector 28 is 4.0 kgf/crn"
・When the inflow l is lj2/sin, 10 Nu/si
It has been experimentally confirmed that n.

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 (
It is shown in Table 2.3. In Table 2.3, Comparative Example (A) is an apparatus that mainly uses dispersed bubbles as explained in the [Prior Art] section, and Comparative Example (B) is an apparatus that mainly uses dispersed bubbles as explained in the [Prior Art 1] section. 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, it is possible to carry out coagulation flotation separation treatment corresponding to 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, and in comparison example (A)
However, from the analysis values of the treated water shown in Table 2,
The agglomeration flotation separation accuracy is higher in Example (1) than in Comparative Example (A). Although Comparative Example (B) requires considerably longer residence time than Example (1), the accuracy of coagulation flotation separation is considerably inferior to Example (1) from the analytical values. As described above, according to this example, the coagulation flotation separation rate is considerably high, and the accuracy is very excellent, and it has been confirmed that effective coagulation flotation separation treatment can be performed efficiently depending on the type of waste liquid. Ta.

In the embodiment described above, the treated water extracted from the flotation tank 6 is guided to the pump 10, and air bubbles are dispersed and dissolved in this water to obtain the flotation fraction IIN! I had set it back to 6. The connection relationship between the pump 10 as a bubble generator and the flotation separation tank 6 is not limited to the above configuration. For example, as shown in FIG. 1(b), the relationship between the reaction M11 and the flotation fraction #W6 is A pump 1° may be provided in between, and the entire amount of pretreated wastewater sent from one reaction tank 1 may be passed through the pump 10, pressurized together with air, and sent to the flotation separation tank 6.

In addition to the pipeline configuration shown in Figure 1(b),
As shown in C), a bypass pipe Pa is provided to directly communicate the reaction N11 and the flotation tank 6, and approximately half of the pretreated wastewater sent from the reaction tank 1 is transferred to the pump 1O. It may also be pressurized together with air and fed into the flotation separation tank 6. Further, in the above embodiment, the chemical addition lower was provided in the center of the pipe P1 that communicated the reaction tank 1 and the flotation separation tank 6, but the lower part of the drug addition lower was provided in the center of the pipe P1 that communicated the reaction tank 1 and the flotation separation tank 6. A drug addition port may be provided in the middle of the piping.

[Effects of the Invention] According to the coagulation flotation separation method and apparatus according to the present invention, fine dispersed bubbles and precipitated bubbles can be generated in arbitrary amounts and proportions in the waste liquid in the flotation tank, and an organic polymer flocculant can be added to the waste liquid in the flotation tank. It can be used to agglomerate the components to be removed, making it compact and compact.
The present invention has the effect that accurate coagulation flotation separation processing can be efficiently performed on various types of waste liquids using a device with a simple configuration.

[Brief explanation of drawings]

FIG. 1(a) is a schematic block diagram showing an embodiment of the device according to the present invention, and FIGS. 1(b) and (C) show the same embodiment.
A schematic diagram showing another aspect of the connection structure between the pump, the flotation tank, and the reactive species; FIG. 2 is a sectional view of the pump in the same embodiment;
3(a) is a cross-sectional view taken along the line mm in FIG. 2, FIG. 3(b) is a diagram showing the shape of the fluid passage in the same pump, and FIG. 4 is a cross-sectional view of the injector in the above embodiment. 5 is a sectional view showing an improved example of the pump in the above embodiment, FIG. 6 is a sectional view taken along the line VI-Vl in FIG. 5, and FIG. 7(a) is a sectional view of the pump in the above embodiment. space S2
FIG. 8(a) is a perspective view of the improved pump space S2', and FIG. 8(b) shows the fluid in the pump space S2'. FIG. 9 is a cross-sectional view showing another structural example of the pump in the embodiment. 6-flotation separation tank, 7-chemical addition port, 10.-pump as a bubble generator, 28.-injector, W-wastewater. Patent applicant: Nikko Engineering Co., Ltd. Agent
Patent Attorney Norihiro Nishimura JIlr! lI gI Figure 1 cc) Figure 43 (b) Figure 4 Figure 7 (a) (b) Figure 8 @ (b) Figure 9

Claims (2)

[Claims] (1) Generate fine dispersed bubbles and precipitated bubbles in the wastewater in the flotation separation tank in arbitrary amounts and proportions, and add an organic polymer flocculant to the wastewater to coagulate the components to be removed, and remove the coagulated substances. A method for coagulation and flotation of wastewater, characterized in that the component to be removed is floated and separated by adhering to or including the bubbles in the target component. (2) a flotation tank for treating wastewater; a bubble generator for generating fine dispersed bubbles and precipitated bubbles in arbitrary amounts and ratios in the wastewater in the flotation tank; A coagulation flotation separation device comprising: a chemical addition port for adding an organic polymer flocculant into wastewater.