JP3202518B2 - Flotation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flotation / separation apparatus for removing and suspending suspended substances by using, as raw water, industrial water or industrial wastewater containing suspended substances which are relatively easy to float.

[0002]

2. Description of the Related Art Various types of flotation devices have been used as devices for removing suspended substances from factory wastewater containing relatively easily suspended substances such as fish meat proteins and oils.

For example, a flotation apparatus proposed in Japanese Patent Application Laid-Open No. 63-77589 introduces pressurized raw water from the bottom of a cylinder provided at the center of a circular flotation tank and flows the raw water in the circumferential direction. In this method, suspended substances are levitated from a water stream spreading outward (this suspended substance is called "scum"), and treated water is taken out from the bottom of the outermost circular partition wall. In order to prevent the adverse effect of being biased toward the center, a single or double annular partition wall for averaging the water flow in the circumferential direction has been devised.

The flotation apparatus proposed in Japanese Utility Model Application Laid-Open No. 61-175291 is provided with a vertical cylindrical body whose diameter gradually increases toward the top in the center of a circular flotation / separation tank. In this method, raw water is supplied to form an upward flow and a downward flow circulating inside and outside the vertical cylindrical body, so that scum floats on the water surface of the upward flow portion.

Further, in the flotation proposed in Japanese Utility Model Laid-Open No. 2-142690, a vertical cylinder whose diameter gradually increases toward the top is provided at the center of a circular flotation tank, and the outside of the vertical cylinder is provided. The scum is floated while supplying raw water by swirling flow, and the downwardly treated water is discharged through the inside of the vertical cylindrical body.

[0006] The conventional flotation tank is provided in a circular shape because an industrial-scale apparatus usually requires a long continuous operation. This is because the tank has a circular shape so that it can be easily collected at the center of the bottom in order to allow some of the suspended solids to be easily discharged out of the tank.

[0007]

As described above, the conventional flotation apparatus has been variously devised as equipment on an industrial scale, but has the following problems to be solved.

For example, in the apparatus proposed in Japanese Patent Application Laid-Open No. 63-77589, an annular partition is provided to average the water flow in the circumferential direction. However, it is necessary to completely prevent partial generation of the radiation flow. Scum is partially leaked, and it is easy to break down due to uneven distribution of scum, and this is mixed into treated water, causing a problem of reduced treatment water quality, and scum remains inside due to the presence of an annular partition wall There is a problem that scooping of the scum is not easy due to the structure of the apparatus.

The above-described devices proposed in Japanese Utility Model Application Laid-Open No. 61-175291 and Japanese Utility Model Application Laid-Open No. 2-142690 are susceptible to turbulent flow due to upward and downward circulating flow inside and outside the vertical cylinder, and the suspension attached to air bubbles The tendency of floc growth of suspended matter is hindered or separated, and the tendency to miniaturize is unavoidable, and there is a problem that the efficiency of flotation separation is reduced. There is also a problem that the suspended substance hardly adheres to the bubbles and the amount of treated water cannot be increased.

The inventor of the present invention has completed the present invention by repeatedly examining various problems which have been problems in the conventional industrial-scale flotation apparatus as described above. A new type that realizes the miniaturization of the equipment such as the separation tank and the scum removal device required for industrial-scale equipment, while enabling the operation substantially in accordance with the plug flow that provides ideal flotation separation, and the simplified structure. To provide a simple flotation device.

It is another object of the present invention to provide a flotation apparatus which can be easily adjusted at the time of a test run or during operation required for an industrial scale apparatus.

It is still another object of the present invention to provide a flotation apparatus capable of performing flotation with high treatment efficiency and excellent treatment water quality.

Another object of the present invention is to substantially eliminate the need for consideration for removing the accumulated sludge at the bottom of the separation tank (attachment of an apparatus for discharging the accumulated sludge), which has been a major problem in the conventional apparatus. A flotation device is provided.

[0014]

One of the features of the flotation device of the present invention that achieves the above object is that an elongated water passage having at least one horizontal turning portion is provided in an upward open type. A flotation tank, a raw water introduction unit which is opened at the lower end wall of the upstream end of the flotation tank and which allows the raw water containing the suspended substance to be floated and separated to flow in the water flow direction; An air bubble mixing means for mixing air bubbles to be brought into contact with raw water, a drainage part for taking out treated water from a lower end wall at a downstream end of the floating separation tank and discharging the water through an overflow weir, and floating to the surface of the floating separation tank And a floating substance removing means for removing the floating substance (scum) outside the tank.

In the above description, the simplest separation tank having one or more folded portions in which an elongated water passage turns horizontally is provided at the center in the width direction of a rectangular parallelepiped tank in contact with one of a pair of long side walls. In addition, a 180-degree turning type water passage provided with a partition wall separated from the other by a predetermined gap can be used. Further, by increasing the number of partition walls (however, the gap between the pair of side walls of the tank is alternately provided), a separation tank formed to have a meandering water passage can be provided (hereinafter, a single-turn-back configuration). Including "meandering").
With such a separation tank, an elongated water passage that always flows in one direction while the raw water flows in a meandering shape is formed very simply by providing a partition in the rectangular parallelepiped tank, and a substantial plug flow state is realized. Is done.

Further, the outer peripheral side wall surface of the portion where the water passage is turned horizontally may be provided in a substantially semicircular plane. Thereby, the flow of the bypassed raw water becomes smooth. In order to make the outer peripheral side wall surface substantially semicircular in plan, the tank wall of the separation tank itself can be provided in a curved shape, but a semi-cylindrical curved plate is inserted into a rectangular parallelepiped tank and the outer peripheral side of the water passage is formed. Wall surfaces can also be formed. Particularly, according to the insertion method of the semi-cylindrical curved plate, there is an advantage that the tank can be easily manufactured and the curved plate can be easily manufactured and adjusted with a plastic material such as PVC.

The above-mentioned raw water introduction part can be formed by connecting a raw water introduction pipe to the separation tank, but it is preferable that the raw water introduction part be an inlet which spreads in a flat trumpet shape so that the flowing raw water spreads in the width direction of the water passage. Often.

A bubble mixing means for mixing bubbles brought into contact with a suspended substance into raw water generally comprises a pressurized air for pressurizing and mixing air into raw water in the middle of a raw water introduction pipe connected to a raw water introduction section. It is configured by mixing and connecting a pressurized water supply pipe to a mixing means, for example, a raw water introduction pipe. Separately from this, a blow-off pipe for fine bubbles may be provided along the elongated water passage near the bottom of the flotation tank. The fine-bubble blowing pipe extending into the water passage may supply air.However, since the supply of pressurized water and the outflow thereof generate bubbles under reduced pressure at the time of the outflow, the air becomes fine bubbles. preferable.

The blowing pipe for the fine bubbles may extend along the entire length of the water passage, or may be intermittently provided for convenience of installation in the meandering water passage.
The outflow direction of air bubbles and pressurized water may be either up or down. However, if the air is allowed to flow downward, even if suspended substances settle to the bottom of the tank, they are rolled up and attached to the air bubbles to float. Therefore, the method is particularly preferably employed for an apparatus having no means for removing sediment sludge or an apparatus containing a large amount of suspended matter having relatively high specific gravity or low hydrophobicity in raw water.

The pressurized water mixed with raw water or bubbles to be supplied to the water passage can be in the same pressure state as in the conventional apparatus, and is not limited.
(About 5 to 30 ° C.) pressurized water of 7 kg / cm ² or less, preferably about 4 to 5 kg / cm ² can be used.

The drainage part of the treated water is configured to be drained through an overflow weir provided in a discharge tank connected to the lower part of the separation tank by a communication pipe, and the separation is performed by adjusting the height of the overflow weir. The water level in the tank can be easily adjusted. Therefore, the adjustment at the time of installation of the device for setting the scraping height to the height at which the moisture content of the scum is reduced, and the adjustment during operation, do not depend on the complicated adjustment of the overflow weir on the outer circumference of the conventional circular separation tank. Another advantage is that the height can be easily adjusted by adjusting the height of a small overflow weir provided in a small discharge tank.

As the floating substance removing means for removing the floating substance (scum) floating on the surface of the floating separation tank from the outside of the tank, an apparatus for mechanically performing a method called scooping or scraping can be used. Since the separation tank of the present invention can form a flat rectangular top surface of the separation tank to form the water passage in a meandering shape,
It is possible to use a removing means having a simple structure in which a scum is scraped out of the tank by a belt conveyor in which a belt having a scraping claw on its surface is opposed to cover the upper surface of the separation tank.

When this belt conveyor type scraping means is used, there is no particular limitation, but a direction perpendicular to the flow of raw water bypassing the direction of scraping the scum (right angle to the straight line portion of the water passage). Direction).

[0024]

According to the present invention, a substantially rectangular parallelepiped type separation tank is used to carry out substantially plug flow in which raw water containing air bubbles always flows in one direction in an elongated water passage.
An ideal flotation separation operation utilizing the flotation force of bubbles perpendicular to the water flow can be performed.

Further, by extending a blowing pipe for fine air bubbles near the bottom of the separation tank along the water passage, a fine suspended substance, a suspended substance having a relatively large specific gravity, and a suspended substance having low hydrophobicity can be obtained. The substance can also be attached to the microbubbles to reliably float.

The principle of the floating separation of the plug flow performed as described above is shown in FIG.
The explanation will be made with reference to FIG.
A raw water introduction pipe 202 into which pressurized water is mixed is connected to a lower portion of one end side in the long direction of 01 so that raw water flows into the separation tank 201. A communication pipe 203 to a discharge tank 204 having an overflow weir 205 is openly connected to a lower portion of the other end of the separation tank 201 in the longitudinal direction, as shown by a white arrow in the drawing. The raw water that has passed through is used as treated water in the discharge tank 20.
4, and is discharged out of the system from the overflow weir 205. Then, during the passage of the raw water as described above, the pressurized dissolved air mixed in the raw water becomes fine bubbles due to the reduced pressure and rises as shown by an upward arrow, and at this time, the raw water contains The suspended substance that has adhered to the air bubbles and floats up to become a scum 206 floating on the water surface.

FIG. 11 also shows the principle of floating separation of plug flow in a separation tank in which a water passage is drawn linearly for convenience and a blowout tube 207 for supplying fine water to the bottom of the water passage is extended. It is a diagram for explaining, according to the configuration of this diagram, fine bubbles that contribute to the floating of the suspended matter of FIG. 10 are supplied not only with the raw water but also in the middle of the water passage, The floating separation of the suspended matter is more reliably performed.

That is, as can be seen from FIGS. 10 and 11, the flowing direction of the raw water is always one horizontal direction.
On the other hand, the bubbles that cause suspended matter to rise rise without being directly related to the flow of the raw water, so the time required for the bubbles to reach the water surface is long depending on the buoyancy of the bubbles themselves, and the suspended matter adheres. This makes it possible to realize a plug flow that is ideal for floating separation.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings.

Embodiment 1 FIG. 1 is a plan view of a separation tank 1 of the present embodiment. Inside of a rectangular parallelepiped separation tank 1, three partition walls 101 are formed so as to form a meandering elongated water passage. It is provided in a structure partitioned by to 103.

Reference numeral 2 denotes a raw water introduction pipe which is connected and opened at a lower portion of the tank side wall at one end of the meandering water passage, and feeds raw water mixed with pressurized water from a pressurized water mixing pipe (not shown) into the separation tank. It flows in the direction shown by the outlined arrow in the figure.

The inflowing raw water is connected and opened at the lower part of the tank side wall at the other end of the water passage while circulating along the elongated water passage formed by the partition walls 101 to 103 as shown by a white arrow. The water flows into a discharge tank having an overflow weir (both have the same structure as in FIG. 10 and is not shown) through the communication pipe 3 and is discharged from the overflow weir to the outside of the system.

FIG. 2 shows a vertical section of the flotation apparatus having the separation tank 1 taken along the line AA in FIG. In the figure, a portion of the water surface portion that is lightly patterned shows a scum 6 that has floated, a portion of the water portion that is deeply patterned shows a region 8 in which fine bubbles rise, and a white portion of the water is where raw water (treated water) flows. The watering area 9 is shown.

Reference numeral 10 denotes a conveyor device as a scum scraping device provided on the upper part of the separation tank 1. In this embodiment, a conveyor belt 13 is installed between a pair of rollers 11 and 12 so as to be rotatable endlessly. Thus, they are arranged to face each other so as to cover a range slightly protruding laterally from the entire upper surface of the separation tank 1. A scum scraping claw is provided on the surface of the conveyor belt 13.

The conveyor device 10 is rotated endlessly in the direction of the arrow in the figure to scrape the scum 6 on the water surface into the scum receiving hopper 14 provided on the side of the separation tank 1. In addition, the scraping direction by the belt 13 of the conveyor device 10 of this example is set so as to be orthogonal to the straight line portion of the water channel (the water flowing direction and the scraping direction coincide with each other at the 180 ° turning portion). Therefore, the flow of the raw water bypassing the scum at the time of scraping has almost no effect, and good scraping can be performed.

Embodiment 2 The present embodiment shown in FIGS. 3 to 5 shows an example in which a fine-bubble blowing pipe 7 is provided along the water passage of the separation tank 1 of Embodiment 1 at the bottom thereof. Since other configurations are the same as those of the first embodiment, common devices, members, and the like are denoted by the same reference numerals, and description thereof is omitted.

The blowing tube 7 for fine bubbles, which is a feature of this embodiment.
Are extended linearly from the pressurized water supply pipe 71 outside the tank to four linear water passages partitioned by the partitions 101 to 103, respectively, as shown in FIG.

The pressurized water supplied from each microbubble blowing pipe 7 is decompressed by flowing out of the pipe 7 to generate fine bubbles (fine bubble area 20 lightly patterned in water in FIG. 5). The assurance of the adhesion and floating of suspended substances in water is further ensured.

Embodiments 3 to 6 Embodiments 3 and 4 show modifications of Embodiment 1. In Embodiment 3 shown in FIG. 6, the outer peripheral side wall surface 31 of the 180 ° turning portion of the water passage is substantially half-plane. In this example, a circular separation tank 30 is used. Other configurations are the same as those of the first embodiment. According to the third embodiment, the generation of turbulence of the raw water (processed water) circulating around is suppressed and the flow becomes smooth, and the possibility of the suspended matter adhering to the bubbles being separated can be reduced.

In the fourth embodiment shown in FIG. 7, a rectangular parallelepiped tank is divided by partitions 101 to 103 in the same manner as in the first embodiment, and a half-cylindrical curved plate 41 is provided at the 180 ° turning portion of the water passage. An example is shown in which the outer peripheral side wall surface of the 180 ° turning portion is formed into a substantially semicircular plane as in the third embodiment by assembling the outer peripheral side wall surface portion. Other configurations are the same as those of the first embodiment. According to the fourth embodiment, in addition to the effect of the third embodiment, there is an advantage that the production of the separation tank is extremely easy.

Embodiments 5 and 6 show modifications of Embodiment 2.
The fifth embodiment shown in FIG. 8 is a separation tank 30 according to the third embodiment in which the outer peripheral side wall surface 31 of the 180 ° turning portion is formed in a substantially semicircular plane.
And a pressurized water supply pipe 71 outside the tank shown in FIGS.
And a blow-out pipe 7 for microbubbles extending therefrom. Other configurations are the same as those of the second embodiment. According to the fifth embodiment, the advantage of the above-described second embodiment, that is, the effect of reliably floating and separating suspended substances, and the advantage of the third embodiment, that is, the effect of smooth flow of raw water (processed water) circulating around. Are also obtained.

Embodiment 6 shown in FIG. 9 is a separation tank according to Embodiment 4 in which a semi-cylindrical curved plate 41 is attached to the outer peripheral side wall portion of a 180 ° turning portion of a water passage formed in a rectangular parallelepiped tank. 40
And a pressurized water supply pipe 71 outside the tank shown in FIGS.
And a blow-out pipe 7 for microbubbles extending therefrom. Other configurations are the same as those of the second embodiment. According to the sixth embodiment, the advantage of the above-described second embodiment, that is, the effect of reliably floating and separating suspended substances, and the advantage of the fourth embodiment, that is, the effect of smooth passage of raw water (processed water) circulating around. In addition, the effect that the production of the separation tank is simple can be obtained.

[0043]

The flotation device of the present invention can substantially operate an ideal plug flow for flotation and separation of suspended solids while passing raw water from one end to the other end of an elongated water passage. In addition to the wall structure of the separation tank that forms the water passage, a small separation tank can be formed by forming the water passage in a meandering shape, which is required for equipment on an industrial scale. The scum removal device attached can be shared and installed in a meandering water channel, so that it is small and simple using a conveyor or the like. Is obtained.

In an industrial-scale flotation apparatus, it may be necessary to adjust the water level during test operation or during operation of the apparatus. This adjustment of the water level is communicated with a separation tank. An effect is also obtained in that it can be easily performed only by adjusting the height of the overflow weir having a small structure.

Further, it is possible to substantially realize an ideal plug flow process in which raw water mixed with pressurized air flows in a horizontal direction orthogonal to a rising direction of bubbles in which suspended matter adheres and floats. Since the device is a device, turbulence is unlikely to occur, and raw water is flowed in a rectified state over an elongated water passage and the rising flow is always given only by air bubbles, so suspended matter comes in contact with air bubbles in the middle of water flow The probability is higher than that of the conventional apparatus, and there is no influence of separation of suspended matter and bubbles. Therefore, an effect that high-efficiency flotation with high treated water quality can be obtained is obtained. In addition, sludge is hardly deposited on the bottom of the tank because of excellent floating separation efficiency of suspended matter, and an effect that a device for discharging the deposited sludge can be substantially eliminated is also obtained.

Further, according to the structure in which the blow-out pipe of the fine bubbles is extended along the elongated water passage near the bottom of the flotation / separation tank, the probability that the above-mentioned suspended solids come into contact with the bubbles can be further increased. The effect is obtained that the efficiency and the quality of the treated water are further improved, and the accumulation of sludge on the tank bottom can be more reliably prevented.

Further, in the case where the blowing tube for the fine bubbles is provided, even a raw water containing a suspended substance having a relatively high specific gravity or a suspended substance having a low hydrophobicity can be efficiently treated. In addition to the above-mentioned food manufacturing waste liquid, there is also obtained an effect that a pulp waste liquid, a general industrial waste liquid, an industrial water, or the like, which cannot always be efficiently treated by a conventional apparatus, can be suitably performed.

[Brief description of the drawings]

FIG. 1 is a plan view of a separation tank used in a flotation separation device according to a first embodiment.

FIG. 2 is a longitudinal sectional view corresponding to a section taken along the line AA of FIG. 1 of the flotation separation device of the first embodiment.

FIG. 3 is a plan view of a separation tank used in the flotation device of the second embodiment.

FIG. 4 is a longitudinal sectional view taken along line BB of FIG. 3;

FIG. 5 is a longitudinal sectional view corresponding to a section taken along the line C-C of FIG.

FIG. 6 is a plan view of a separation tank used in a flotation separation device according to a third embodiment.

FIG. 7 is a plan view of a separation tank used in a flotation separation device according to a fourth embodiment.

FIG. 8 is a plan view of a separation tank used for a flotation separation device according to a fifth embodiment.

FIG. 9 is a plan view of a separation tank used in a flotation separation apparatus according to a sixth embodiment.

FIG. 10 is a diagram illustrating the principle of floating substance floating separation of a plug flow realized by the present invention using a separation tank having a straight water passage.

FIG. 11 is a view similar to FIG. 10 and illustrates the principle of floating substance floating separation of the plug flow realized by the present invention, using a separation tank in which a blow-out tube for fine bubbles is extended in a straight water passage.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Separation tank, 2 ... Raw water introduction pipe, 3 ... Communication pipe, 6 ... Scum, 7 ... Fine bubble blowing pipe,
8 ... Area where fine bubbles rise, 9 ... Area through which raw water (treated water) flows, 10 ... Conveyor device, 1
1,12: roller, 13: conveyor belt, 1
4 ... hopper, 20 ... fine bubble area, 30 ...
Separation tank, 31 ... outer peripheral side wall surface of 180 ° turning portion, 40
... Separation tank, 41 ... Semi-cylindrical curved plate, 71 ...
Pressurized water supply pipes, 101 to 103 ... partition walls.

Continuation of the front page (56) References JP-A-7-949 (JP, A) JP-A-60-132805 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) C02F 1 / 24 B01D 17/00-17/12

Claims (5)

(57) [Claims] 1. A flotation / separation tank having an elongate water passage having one or more turning portions that turn horizontally and provided in an upward open type, and an opening at a lower part of an end wall at an upstream end of water flow of the flotation / separation tank. Raw water introduction section for flowing raw water containing suspended matter to be floated and separated in the water flow direction, bubble mixing means for mixing bubbles to be brought into contact with the suspended substance into raw water, and a downstream end of flow of the floating separation tank A drainage part for taking out the treated water from the lower part of the end wall and discharging through the overflow weir, and a floating substance removing means for removing the floating substance floating on the water surface of the floating separation tank outside the tank. Flotation device. 2. A floating air mixing means according to claim 1, wherein said air bubble mixing means for bringing air bubbles into contact with said suspended substance is a pressurized air mixing means for pressurizing and mixing air into raw water flowing from a raw water introduction section. A flotation device characterized by at least one of a microbubble blowing pipe extending in the vicinity along an elongated water passage. 3. The flotation apparatus according to claim 1, wherein the elongated water passage of the flotation tank is provided in a meandering manner. 4. The method according to claim 1, wherein
A flotation device wherein the flotation material removing means for removing the flotation material from the flotation tank outside the tank is a scraping device for scraping the flotation material substantially horizontally and perpendicularly to the water passage. 5. The method according to claim 1, wherein
A flotation / separation device characterized in that the outer peripheral side wall surface of the part where the elongated water passage of the flotation / separation tank turns horizontally is provided in a substantially semicircular plane.