JPS5857237B2 - flotation separation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to an apparatus for flotation separation of a specific substance to be separated from a waste liquid containing a suspended or sedimentary specific substance. The present invention relates to an apparatus for flotation separation of specific substances by adhering or adhering them to air bubbles dispersed in a circulating liquid by appropriate means.

Various devices have been proposed in the past in which specific substances are bonded or adhered to air bubbles dispersed in a liquid and floated and separated.

The most important requirements for this type of flotation separation device are (1) the presence of a compartment or auxiliary tank inside or outside the flotation tank, and (2) the presence of a chemical (i.e., organic polymer flocculant)-added carbo into the waste liquid. What to do when fine air is dispersed in
(3) Only a small amount of chemicals are needed; (4) the air dispersed in the waste liquid is made into fine bubbles; (5) it is simple and compact; (6) the manufacturing cost is low. (7) Intermittent operation is possible, and (8) it is possible to respond to fluctuations in the specific substance load and water amount. If any of the above requirements is missing, appropriate treatment cannot be performed.

However, no conventional flotation separation device satisfies two or more of the above requirements at the same time, and therefore effective separation results may not be obtained, or the device may become complicated or oversized, or The current situation is that many chemical additions are required.

Furthermore, in relation to the above-mentioned requirements for flotation separation equipment, as will be described in more detail later, as a result of various experiments, when there is no compartment or auxiliary tank, the cross section of the auxiliary tank is circular or circular. If it is not square, if the discharge port for circulating fluid and air bubbles is not inserted somewhat deeply into the auxiliary tank, or if the chemical is not added when fine air is dispersed in the waste liquid. It was found that the treatment effect of the flotation separation device was particularly poor.

Also, considering the generation and supply means of micro air bubbles,
In a flotation separator that sucks or blows air directly into the waste liquid without using the circulating liquid, instead of sucking or blowing fine air bubbles into the circulating liquid, the floating scum is removed from the tank when the equipment is out of operation. This method has the drawback that the scum will precipitate again in the water, and the scum will flow out together with the processing liquid at the next startup.Furthermore, as will be described later, it is difficult to maintain the waste liquid-to-air ratio above a certain limit, making it difficult to use for general purposes. There is a problem when the point and the loading amount of the specific substance change.

There is a type that combines waste liquid and circulating liquid and sucks or blows air into it, but since the amount of waste liquid, circulating water, and air amount are linked, it is difficult to adjust the equipment, and adjustment is not required. In this case, fluctuations in the amount of raw water affect the amount of waste liquid and circulating water, which has the disadvantage that the outer ring becomes unstable.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an improved flotation device which overcomes the drawbacks of conventional devices.

Another object of the present invention is to provide a flotation separation device that generates fine air bubbles and can treat waste liquid very effectively.

That's true. Still another object of the present invention is to provide an extremely simple and compact flotation separation device in which an auxiliary tank can be disposed inside or outside the flotation tank as desired.

Another object of the present invention is to provide a flotation separation device that minimizes the required amount of added chemicals and can quickly cope with changes in the load amount of a specific substance to be separated and the amount of water.

To summarize the present invention, the present invention is a bubble contact type flotation separation method in which suspended or sedimentary substances present in waste liquid are adhered or adhered to air bubbles dispersed in circulating liquid and floated and separated as scum. The device is equipped with a flotation tank for floating scum and an auxiliary tank having an elongated body. a mixing zone (I) that mixes the suspended or sedimentary substance and fine air bubbles; A flocculation reaction zone (■) in which a polymer flocculant is injected into the liquid to generate aggregates (flocs) of air bubbles and suspended or sedimentable substances; sex frock,
In order to levitate even flocs with a slow floating speed, the device is configured to have an upward flow imparting zone side for making the jet action of the circulating fluid effective.

Therefore, (2) a raw liquid inflow pipe for supplying raw waste liquid;
An organic polymer flocculant cooling pipe for adding an organic polymer flocculant and a circulating fluid discharge pipe for supplying a circulating fluid containing micro air bubbles are each provided separately in the auxiliary tank.

(3) The opening of the organic polymer flocculant addition pipe to the auxiliary tank is more open to the flotation tank of the auxiliary tank than the opening of the original liquid inflow pipe to the auxiliary tank and the discharge opening of the circulating fluid discharge pipe to the auxiliary tank. Must be located close to the end.

Furthermore, (4) the circulation means for supplying the circulating fluid containing fine air bubbles from the flotation tank to the auxiliary tank via the circulating fluid discharge pipe includes a circulation pump that supplies the circulating fluid from the flotation tank to the circulating fluid discharge pipe, and the surrounding atmosphere. an ejector that sucks more air into the circulating fluid;
It is characterized by comprising a fixed pipe mixer for forming fine bubbles from the air sucked into the circulating fluid by the ejector.

Next, the flotation and separation device according to the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows one embodiment of a flotation separation device according to the present invention.

The flotation separation device 1a in this embodiment includes a flotation tank 3, an auxiliary tank 2 disposed outside the flotation tank 3, and the flotation tank 3.
A circulation means 10 is provided for sending and circulating circulating fluid from the auxiliary tank 2 to the auxiliary tank 2.

The auxiliary tank 2 has an elongated body 4 which is preferably circular or square in cross section, and one end or upper part 6 of the body is in the shape of an upwardly diffused funnel and is open to the flotation tank. The auxiliary tank 2 and flotation tank 3 are brought into fluid communication.

The other end of the auxiliary tank 2, that is, the bottom 5, is in fluid communication with the circulation means 10, which is equipped with a circulating fluid delivery pump 1σ, for discharging the circulating fluid from the flotation tank 3 into the auxiliary tank 2. A circulating fluid discharge pipe 7 is provided.

The circulating fluid discharge pipe 7 has a discharge opening 7' connected to the auxiliary tank 2.
It is preferable to install the auxiliary tank 2 by protruding it into the auxiliary tank 2 so that it is located inwardly at a position spaced apart from the bottom 5.

In the body 4 of the auxiliary tank 2, a stock liquid inflow pipe 8 is arranged close to the bottom part 5, and a drug addition pipe 9 is arranged at a position closer to the upper part 6 from the stock film liquid inflow pipe 8. Ru.

Further, to explain in detail the structure of the auxiliary tank 2, as will be understood with reference to FIG.
The mixing zone (1) mixes the raw waste liquid and the circulating liquid containing fine air bubbles from the flotation tank, and the mixing zone (1) is connected to the mixing zone, and the air bubbles formed in the mixing zone are mixed with suspended or sedimentary substances. A flocculation reaction zone in which aggregates of air bubbles and suspended or sedimentary substances are generated from a mixed liquid by the action of an organic polymer flocculant.
and a tube extending vertically between the flocculation reaction zone and the open end of the elongated body to the flotation tank for floating floating aggregates formed in the flocculation reaction zone to the flotation tank. It has an upward flow imparting zone (■).

Therefore, the circulating liquid discharge pipe 7 and the stock liquid inflow pipe 8 are connected to the mixing zone (2) of the auxiliary tank 2, and the organic polymer flocculant addition pipe 9 is connected to the flocculation reaction zone (2).

In the flotation separator 1a configured as described above, the circulating liquid containing dispersed microbubbles is transferred to the auxiliary tank body 4 through the pipe 7 provided at the auxiliary tank bottom 5 by the pressure of the circulation pump 10'.
is press-fitted into the

On the other hand, the raw waste liquid is preferably supplied to the body 4 via a pipe line 8 from a waste liquid tank provided at a suitable location without using a delivery pump.
and is stirred and mixed by the turbulent flow caused by the forced injection of circulating fluid.

Next, a chemical is pressurized into the auxiliary tank body 4 through a pipe 9 by a chemical injection pump (not shown), and due to the action of the chemical, the specific substance to be separated and air bubbles in the mixed liquid adhere or adhere to each other, and are transferred from the upper part 6 of the auxiliary tank to the flotation tank. 3, it is released with the liquid.

Next, the floating scum and liquid are separated in the floating tank 3.

The cross section of the body 1 is circular or square as described above, and this shape is important as will be described later.

The flow rate of the body 4 is related to the above-mentioned mixing time and the time during which the drug acts, and it is preferable that the former be relatively short and the latter be relatively long.

If the mixing time is not long, bubbles will aggregate and the flotation effect will deteriorate.

The pressure at the discharge port is also related to time, so it is 0.3 kg/
It is preferable to set it to crA or more.

It is important to add chemical additives in the form of fine bubbles dispersed in the waste liquid; as will be described later, if they are added directly to the waste liquid or to the circulating liquid, the treatment effect will be poor.

Note that a pressure pump is not required for the inflow of raw waste liquid.

As shown in the figure, the circulating fluid discharge pipe 7 is inserted into the body 4 so that the circulating fluid discharge lower' in the auxiliary tank 2 is provided at a position spaced further inward from the bottom 5 of the body 4. In addition, it is important that the discharge lower ' is smaller in diameter than the body 4. By configuring it in this way, the fluid is effective for suctioning the stock solution, mixing the stock solution and circulating fluid, and for medicinal action. It is possible to create a turbulent state of flow.

If it is not constructed as described above, it will not be able to cope with fluctuations in the flow rate of the stock solution, and the processing effect will be poor.

The flotation separator 1a according to the present invention operates extremely effectively by being provided with a simple and small-sized auxiliary tank having the above-described structure.

FIG. 3 shows a flotation separation device 1c according to another embodiment of the present invention, in which an auxiliary tank 2 is disposed inside a flotation tank 3.

The flotation and separation device 1C has approximately the same configuration as the flotation and separation device 1a shown in FIG.
The difference is that a stationary fluid (liquid and air) shearing/mixing means, that is, a stationary pipe mixer 13 and an ejector 12, are provided between the pump and the circulating fluid discharge pipe 7.

To explain the operation of the flotation separation device 1c, the circulating liquid reaches the circulation pump 10' from the bottom 3' of the flotation tank 3 via the flow control valve 20 and the pipe 14, and the pump 1
0' is press-fitted into the ejector 12.

In the ejector 12, compressed air flowing through an adjustment valve 21 is forced into the ejector mechanism 12 from an inflow pipe 11 provided in the ejector.

The air is then dispersed and atomized into the circulating fluid in the pipe mixer 13 and is forced into the auxiliary tank 2 via the pipe 7.

The scum floating in the flotation tank is discharged to the outside of the yarn by a scum scraping device 17, and the processing liquid is discharged from an overflow mechanism 18.

Reference numerals 15 and 16 indicate a drug injection pump and a drug tank.

As will be described in detail later, it has been found that by using the pipe mixer 13, the bubbles are made extremely fine and the waste liquid treatment effect is significantly improved compared to the case where the pipe mixer is not used.

In addition, it is preferable that the flow velocity in the pipe mixer 13 is relatively fast; if the flow velocity is slow, the bubbles will become coarse and the flotation effect will be deteriorated.
Furthermore, various experiments have shown that the amount of pressurized air is preferably within 70% of the circulating fluid amount in terms of normal volume, and that if more air is pressurized, it will cause disturbance in the auxiliary tank 2 and deteriorate the treatment effect.

FIG. 4 shows a flotation and separation device 1d according to the present invention, which has approximately the same configuration as the flotation and separation device 1c shown in FIG.

In the flotation separation device 1d, the circulation means 10 includes an ejector 1 between the bottom wall 3' of the flotation tank 3 and the circulation pump 10'.
2 is provided, a pipe mixer 13 is provided between the pump 10' and the circulating fluid discharge pipe 7, and the inflow of air into the ejector 11 via the regulating valve 21 and the ejector inflow pipe 11 is controlled by the circulating fluid. This is configured to be performed by the suction force of the pump 10'.

In other words, the third point is that the structure is configured so that air is not pressurized.
This is different from the flotation separation device 1c shown in the figure.

It is preferable that the flow velocity in the pipe mixer is 1.5 m/sec or more, and the amount of air is within 60% of the amount of circulating water.Also, if a pipe mixer is not used, it is difficult to obtain good results due to variations in bubble diameter. I found out.

In this embodiment, compressed air is not used except for a slight difference in the amount of air, so the mechanism is simpler than the flotation separator 1C shown in FIG. 3, and in terms of treatment effects, under normal operating conditions, As will be described later, a good formation comparable to that of the flotation separation device 1c was obtained.

However, differences in the amount of air may lead to differences in treatment effectiveness under extreme conditions.

As explained above, in the present invention, by using the pipe mixer 13, dispersed microbubbles can be generated and the treatment effect can be significantly improved.

Next, the present invention will be described in more detail with reference to Examples.

Example 1 In the flotation separation device shown in FIG. 3, the actual volume of the flotation tank 3 is set to 150. g. The vertical auxiliary tank 2 is used, the cross section of the body 4 is circular, and its dimensions are 80 mmφ x 400 m.
rn, the diameter of the circulating water discharge lower' is 16.1 mmφ, the discharge port insertion depth H is 50 mm, and the inlet 8 of the stock solution inflow pipe 8.
An apparatus was used in which the hole 9' of the drug addition conduit 9 was positioned 200 mm from the bottom 5 of the auxiliary tank.

The pipe mixer 13 used was one in which three mixing elements were placed in a passage pipe.

Furthermore, the amount of raw liquid is supplied at 20,1/min, the amount of circulating liquid is 201/mix, and the amount of blown air is 12 t/mi! The discharge pressure of the circulation pump 10' at that time is 0.8 kg.
/cyst, the compressed air pressure was 0.3 kg/cvt, and the flow velocity in the pipe mixer was 26 m/sec.

The stock solution was supplied using a constant head tank.

Zinc die-casting factory wastewater was selected as the waste liquid, and LAS (trade name) was added to the raw waste liquid as a pretreatment at a rate of 300 μ/l, sulfuric acid at 120 μ/l, and PAC at 1000 μ/l, and the mixture was stirred for 10 minutes. Furthermore, caustic soda 2551rI
? /, g was added and stirred for 5 minutes.

Supply the waste liquid after pretreatment to the above device under the above operating conditions,
At the same time, a chemical injection pump is used to produce organic polymer... IMOLOCK M-
366 (trade name) 0.1% solution at 100 cc/mi
The results shown in Table 1 were obtained by continuous addition at a ratio of n (5 m9/7 as a dry amount).

According to this, it was found that the flotation separation device according to the present invention shown in FIGS. 1 to 3 can be used as a practical device.

Example 2 Processing was carried out under the same conditions as in Example 1, except that the auxiliary tank 2 of the apparatus in Example 1 was removed from the flotation tank 3.

The results are shown in Table 1.

This revealed that the auxiliary tank was effective.

Example 3 The cross section of the auxiliary tank body 4 of the device in Example 1 was 170 m.
Processing was carried out under the same conditions as in Example 1 except that the shape was a rectangle of m×30 mrn.

The results are shown in Table 1. This revealed that the shape of the cross section of the auxiliary tank affects the floating effect.

Considering the mixing in the auxiliary tank and the effect of the drug, a circular or square shape was considered preferable.

Example 4 The process was carried out under the same conditions as in Example 1, except that the insertion part of the circulating fluid discharge pipe into the auxiliary tank 2 was removed.

The results are shown in Table 1.

As an observation, fluctuations in the liquid level were observed at the opening of the auxiliary tank.

This revealed the effect of inserting the discharge port.

Example 5 The treatment was carried out under the same conditions as in Example 1 except that the addition hole 9' of Bimorok M-366 was attached to the stock solution inflow pipe 8, and the amount of Bimorok M-366 added was doubled. I got 2.

From Table 1, it was found that the position at which the chemical was added affected the floating performance, and that if the chemical was added directly to the waste liquid, a large amount was required.

The same was true when adding water directly to the circulating water.

Additionally, it was observed that flocs were entrained in the treated water.

Example 6 Aviation air cleaning wastewater was selected as the waste liquid, and 1. After adding 0 m9/l of OO and stirring for 10 minutes, 100 m/l of caustic soda was added and 1
Stirred for 0 minutes.

The waste liquid after pretreatment was supplied to the apparatus of Example 1 under the same operating conditions, except that for chemical injection, 200 c of a 0.1% solution of No.
The good results shown in Table 2 were obtained by continuous addition at a rate of c/min (dry amount: 10 m9/l).

Example 7 The pipe mixer was removed from the apparatus of Example 6, and the treatment was carried out under the same conditions as in Example 6, except that the same locations were connected through pipes of the same diameter.

The results are shown in Table 2. As shown in the table, the results were poor and considered unsuitable for practical use, and it was confirmed that the use of a pipe mixer was effective.

What was observed was that in the open area of the auxiliary tank, there was a violent fluctuation in the liquid level that is sometimes seen when water boils.

Example 8 Gas station wastewater was selected as the waste liquid, 30% of PAC was added to the raw waste liquid as a pre-treatment, and thione BB
(trade name) was added thereto and stirred for 10 minutes.

In the device, remove the ejector from the device of Example 6,
The mouth part was connected with a pipe, and the ejector was attached to the inlet side of the circulation pump, and the amount of air sucked into the boxstock was adjusted to 10 liters/min.

Other medicines include Bimorok M-366 at 5m.
The pretreated waste liquid was treated using the same equipment and operating conditions as in Example 6, except that / was added.

However, the flow velocity inside the pipe mixer was slowed down by the amount of intake air decreased.

The processing results are shown in Table 3.

As shown in the table, it was found that good treatment effects were obtained.

Example 9 Processing was carried out under the same conditions as in Example 8, except that the pipe mixer was removed from the apparatus of Example 8 and the same locations were connected through pipes of the same diameter.

As shown in the table, the results were slightly worse than those of Example 8, and this was thought to be due to the difference in effectiveness due to the use of the pipe mixer.

As an observation item, the mixed liquid containing air bubbles was quickly taken out from the middle part of the body of the auxiliary tank using a soft vinyl hose, introduced into the gap between two transparent glass plates attached to the hose, and the bubble diameter was observed with the naked eye. Compared to Example 8, the content of coarse bubbles with a diameter of 1 cm or more was higher.

In this flotation process, coarse bubbles are considered to have little or no effect on flotation and removal of the specific substance, and the variation in bubble properties (i.e., the content of coarse bubbles) is the reason for the difference in flotation effect. It is thought that it appeared.

As described above, the flotation separation device according to the present invention not only provides a flotation separation effect that was not possible with conventional technology, but also has a simple mechanism, which improves the practicality and economic efficiency of the device. It has a great effect on improving.

Moreover, by configuring the present invention as described above, ■ the amount of organic polymer flocculant required to be added is minimized, ■ a large amount of fine air bubbles are generated, and ■ the suspension or sedimentation in the stock solution is reduced. An extremely simple and compact system that increases the flocculation of substances, and (1) allows even flocs with a slow floating speed to float upward into the flotation tank, (2) thereby processing waste liquid extremely effectively and efficiently. equipment can be provided.

It has the following effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing one embodiment of a vertical flotation separation device according to the present invention. FIG. 2 is a schematic enlarged view of the auxiliary tank of the flotation separator according to the present invention. FIG. 3 is a schematic cross-sectional view showing an embodiment of the flotation separation device according to the present invention in which an auxiliary tank is provided in a flotation tank. FIG. 4 is a schematic cross-sectional view showing another embodiment of the flotation separation device according to the present invention in which an auxiliary tank is provided in the flotation tank similarly to FIG. 3. 1 (1a, 1c, 1d): flotation separation device, 2: auxiliary tank, 3: flotation tank, 4: auxiliary tank body, 7: circulating fluid discharge pipe, 8: raw wastewater inflow pipe, 9: drug addition conduit,
10: circulation means, 10': circulation pump, 12: ejector, 13: pipe mixer.

Claims (1)

[Claims] 1. A bubble contact type flotation separation device in which suspended or sedimentary substances present in waste liquid are adhered or attached to air bubbles dispersed in circulating liquid and floated and separated as scum. a flotation tank for floating the scum; the elongated body is connected to a mixing zone for mixing raw waste liquid and a circulating liquid containing fine air bubbles from the flotation tank; , a flocculation in which an aggregate of air bubbles and a suspendable or sedimentable substance is generated from a mixed liquid of air bubbles and a suspendable or sedimentable substance formed in the mixing zone by the action of an organic polymer flocculant. a reaction zone;
an upward flow extending vertically between the flocculation reaction zone and the open end of the elongated body to the flotation tank for floating floating aggregates formed in the flocculation reaction zone to the flotation tank; an auxiliary tank having a supply zone; and a circulation means for sending circulating liquid containing fine air bubbles from the flotation tank to the auxiliary tank; disposed between the circulation means and the auxiliary tank; a circulating fluid discharge pipe connected to the auxiliary tank so that the discharge port is located in the mixing zone of the auxiliary tank; and a source liquid connected to the mixing zone of the auxiliary tank to supply raw waste liquid to the auxiliary tank. an inflow pipe; and an organic polymer flocculant addition pipe connected to a flocculation reaction zone of the auxiliary tank for adding the organic polymer flocculant to the auxiliary tank, and the circulating means is configured to supply the organic polymer flocculant from the flotation tank to the flocculation reaction zone of the auxiliary tank. A circulation pump that feeds the circulating fluid that has been treated in the flotation tank and has very little suspended or sedimentary substances to the circulating fluid discharge pipe connected to the auxiliary tank, and a circulating pump that sucks air from the surrounding atmosphere into the circulating fluid. A flotation separation device comprising: an ejector for causing air to flow into the circulating fluid; and a stationary pipe mixer for forming fine bubbles from the air sucked into the circulating fluid by the ejector. 2. A patent in which the auxiliary tank is arranged to extend in the vertical direction, the upper end is open to the flotation tank, and an upward flow imparting zone, a flocculation reaction zone, and a mixing zone are arranged in order from the upper end to the lower end. An apparatus according to claim 1. 3. The device according to claim 1 or 2, wherein the circulation means has a device for further pressurizing the air flowing into the ejector device. 4. Claim 1, characterized in that a circulation pump is provided between the ejector and the fixed pipe mixer,
The device according to item 2 or 3. 5 Claims 1, 2, or 4, characterized in that a circulation pump is provided between the ejector and the flotation tank.
Apparatus described in section. 6 Claim 1, wherein the ejector is provided with an adjustment valve that adjusts the amount of air sucked into the ejector.
The device according to any one of Items 1 to 5. 7. The device according to claim 1 or 2, wherein the cross-sectional area of the body of the auxiliary tank is larger than the discharge opening area of the circulating fluid discharge pipe provided at the end of the body.