JP2006297239A - Pressure floatation separation apparatus in waste water treatment, sludge concentration system and pressure floatation separation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a solid content recovery rate by generating finer bubbles in a pressure floatation separation apparatus for waste water treatment. <P>SOLUTION: The pressure floatation separation apparatus 1 is provided with a floatation separation tank 5 configured to keep an airtight state blocking the gas phase part 51 in the tank from the air outside or substantially blocked. Then, the pressure floatation separation apparatus 1 is configured so as to generate bubbles under the gas phase part 51 having a higher pressure than an atmospheric pressure in the floatation separation tank 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a pressurized flotation separation device, a sludge concentration system, and a pressurized flotation separation method in wastewater treatment.
More specifically, the present invention relates to a pressurized flotation separation apparatus for wastewater treatment that can improve the solid content recovery rate by generating finer bubbles.

Conventionally, a solid-liquid separation method called “flotation separation method” is known in the field of wastewater treatment. In this method, fine bubbles are attached to solid particles contained in a waste liquid, and suspended substances are floated and concentrated by the buoyancy of the attached bubbles. The fine bubbles can be generated by dissolving air in a liquid under pressure, releasing the liquid into waste liquid in a floating separation tank that is open to the outside air, and returning to atmospheric pressure (for example, Non-patent document 1).
Editor, Shigehisa Iwai, “Wastewater / Waste Treatment Wastewater”, Kodansha, September 1, 1980, p.113

  However, in the conventional levitation separation method, it cannot be said that the size of the fine bubbles to be floated is sufficiently small, and it has been difficult to float and concentrate to solid particles smaller than the fine bubbles. For this reason, small solid particles remained in the floating separation tank, and as a result, the recovery rate of the solid content was reduced. In addition, when bubbles rise, some of the water adhering around the bubbles also floats, but if the bubbles are large, the amount of water adhering increases, and as a result, the solid content after floating The concentration will decrease.

  For this reason, in actual sites, it is common practice to increase the particle size of solid particles by adding a polymer flocculant before or during levitation concentration. However, when composting concentrated sludge after separation, a polymer flocculant that is a chemically synthesized substance cannot be added, and thus the above-described problems still remain.

(Object of the present invention)
Accordingly, an object of the present invention is to improve the solid content recovery rate by generating finer bubbles in a pressurized flotation separation apparatus in wastewater treatment.

  Another object of the present invention is to reduce the amount of water adhering to the bubbles and prevent a decrease in the concentration of the separated solids by generating finer bubbles in the pressurized flotation separation apparatus in wastewater treatment. It is in.

  Another object of the present invention is to increase the suspended solids in raw water without using a polymer flocculant so that the concentrated sludge after separation can be composted in a compost facility or the like. It is to provide a separation device.

  Still another object of the present invention is to provide a sludge concentration system and a pressurized flotation separation method provided with a pressurized flotation separation device that can achieve the above-mentioned object.

Means taken by the present invention to achieve the above object are as follows.
In addition, although the code | symbol used in drawing is described using the parenthesis in order to help the understanding of description of the effect | action mentioned later, each component is not limited to the thing of drawing description.

In the first invention,
A pressure flotation separation apparatus for wastewater treatment,
The gas phase section (51) in the tank is provided with a floating separation tank (5) configured to be in an airtight state in which the outside air is blocked or essentially blocked,
This is a pressure floating separator.

In the second invention,
A pressure flotation separation apparatus for wastewater treatment,
A floating separation tank (5) configured to be in an airtight state in which the gas phase part (51) in the tank is blocked or essentially blocked from outside air,
In the levitation separation tank (5), it is configured so that bubbles are generated under the gas phase part (51) in a pressure state higher than atmospheric pressure,
This is a pressure floating separator.

In the third invention,
A gas-liquid mixing means (6) for mixing a gas in a liquid under pressure to obtain a first gas-liquid mixed fluid;
A fine bubble generator (7) for generating bubbles by supplying a second gas-liquid mixed fluid into the floating separation tank (5);
With
The fine bubble generating device (7) is provided with an ejector-type nozzle (71) capable of further incorporating gas into the first gas-liquid mixed fluid obtained by the gas-liquid mixing means (6). Features
It is a pressure levitation separator according to the first or second invention.

In the fourth invention,
The ejector-type nozzle (71) has a gas-liquid fluid ejection part (712) for ejecting the first gas-liquid mixed fluid and a negative pressure generated by the ejection of the first gas-liquid mixed fluid to the first gas-liquid mixed fluid. A gas communication part (715) for communicating the sucked gas,
The gas communication part (715) includes a space part (716) communicating over the entire outer periphery of the gas-liquid fluid ejection part (712),
It is a pressurization flotation separation device concerning the 3rd invention.

In the fifth invention,
Characterized in that it is equipped with a flotation separator (1) according to the first, second, third or fourth invention,
This is a sludge concentration system.

In the sixth invention,
A pressure flotation separation method in wastewater treatment,
By blocking or essentially blocking the gas phase part in the levitation separation tank from outside air to make it airtight, the inside of the levitation separation tank is under the gas phase part (51) in a pressure state higher than atmospheric pressure. It is characterized by generating bubbles with
This is a pressure levitation separation method.

(Work)
The pressurized flotation separation device (1) according to the present invention operates as follows.
Since the gas phase part (51) in the levitation separation tank (5) is in an airtight state where it is blocked or essentially blocked from the outside air, it is different from the conventional levitation separation tank opened to the outside air. Thus, the bubbles that have floated from the liquid level of the waste water to the gas phase portion (51) do not escape to the outside air, and the inside of the gas phase portion (51) is maintained at a pressure higher than the atmospheric pressure (outside air). As a result, the hydraulic pressure in the wastewater is also higher than the normal hydraulic pressure (the wastewater hydraulic pressure when the floating separation tank is open to the outside air). Then, the pressurized gas-liquid mixed fluid is released into the waste water in the floating separation tank (5) and becomes a pressure drop state and bubbles, but as described above, it is higher than the normal hydraulic pressure. Since bubbles are formed under a high pressure state, bubbles that are finer than bubbles generated in a floating separation tank under atmospheric pressure are generated.

  In addition, after the occurrence, the fine bubbles that float in the floating separation tank (5) are kept in a pressure state higher than the normal hydraulic pressure, so that they are prevented from becoming larger as they rise, and their size is essential. Ascend while maintaining.

  As described above, the airtight structure of the above-described levitation separation tank (5) allows the generation of finer bubbles and the levitation in a state where the size of the generated fine bubbles is essentially maintained. Even small solid particles, which were difficult with the conventional method, can be levitated and concentrated.

Gas-liquid mixing means (6) that obtains the first gas-liquid mixed fluid by mixing gas into the liquid under pressure, and the second gas-liquid mixed fluid is supplied into the floating separation tank (5) to generate bubbles. A fine bubble generator (7), and the fine bubble generator (7) is an ejector type capable of further incorporating gas into the first gas-liquid mixed fluid obtained by the gas-liquid mixing means (6). The pressurized flotation separation device (1) having the nozzle (71) operates as follows.
The gas-liquid mixing means (6) mixes gas in the liquid under pressure to obtain a first gas-liquid mixed fluid. Further, the ejector-type nozzle (71) of the fine bubble generator (7) takes in a larger amount of gas into the first gas-liquid mixed fluid obtained by the gas-liquid mixing means (6), The gas-liquid mixed fluid becomes the second gas-liquid mixed fluid. Then, the second gas-liquid mixed fluid that has taken in this large amount of gas is supplied into the floating separation tank (5) by the fine bubble generating device (7), and a large amount of fine bubbles are generated.

The ejector-type nozzle (71) ejects the first gas-liquid mixed fluid to the first gas-liquid mixed fluid by the gas-liquid fluid ejection part (712) and the negative pressure generated by the ejection of the first gas-liquid mixed fluid. A gas communication part (715) for communicating the sucked gas, and the gas communication part (715) includes a space part (716) communicating over the entire outer periphery of the gas-liquid fluid ejection part (712). It works as follows.
That is, the first gas-liquid mixed fluid sent to the ejector-type nozzle (71) is ejected from the gas-liquid fluid ejection section (712). Due to the ejection of the first gas-liquid mixed fluid, a negative pressure (low pressure) is generated in the vicinity of the outlet of the gas-liquid fluid ejection portion (712). Due to this negative pressure, gas is sucked from the gas communication part (715), and further gas is mixed or mixed and dissolved in the ejected first gas-liquid mixed fluid, whereby the first gas-liquid mixed fluid becomes the second gas-liquid mixed It becomes a mixed fluid. And since the gas communication part (715) is provided with the space part (716) which communicates over the outer periphery of the gas-liquid fluid ejection part (712), the gas communication part (715) is provided with the gas-liquid fluid ejection part (712 ) Has a wider contact area of the gas with the first gas-liquid mixed fluid ejected from the gas-liquid fluid ejecting portion (712). Thereby, many gases are mixed or mixed and dissolved in the first gas-liquid mixed fluid, and as a result, a large amount of fine bubbles are generated.

The present invention has the above-described configuration and has the following effects.
(A) According to the pressurized flotation separation apparatus and the pressurized flotation separation method according to the present invention, the gas phase portion in the tank in the flotation separation tank is shut off from the outside air or is essentially airtight. Therefore, finer bubbles can be generated than bubbles generated in the floating separation tank under atmospheric pressure. As a result, it is possible to float and concentrate even small solid particles that have been difficult to achieve by the conventional floating separation method using the floating separation tank open to the outside air. As a result, since the solid content recovery rate is improved, it is not necessary to use a polymer flocculant, and the concentrated sludge after separation can be composted in a compost facility or the like.

(B) Further, according to the pressurized flotation separation apparatus and the pressurized flotation separation method according to the present invention, by generating finer bubbles, the amount of water adhering to the bubbles is reduced, and the separated solid content concentration is reduced. It can be prevented from decreasing.

(C) Gas-liquid mixing means for mixing a gas into a liquid under pressure to obtain a first gas-liquid mixed fluid, and generating fine bubbles for generating bubbles by supplying a second gas-liquid mixed fluid into a floating separation tank A gas-liquid mixing apparatus in which the fine bubble generating apparatus includes an ejector-type nozzle that can further introduce gas into the first gas-liquid mixed fluid obtained by the gas-liquid mixing means. By adopting the means and ejector type nozzle, a large amount of gas can be mixed or mixed and dissolved in the gas-liquid mixed fluid supplied to the floating separation tank. Can be generated. As a result, the solid content recovery rate can be further improved.

(D) The ejector-type nozzle is sucked into the first gas-liquid mixed fluid by the gas-liquid fluid ejecting portion for ejecting the first gas-liquid mixed fluid and the negative pressure generated by the ejection of the first gas-liquid mixed fluid. A gas communication part that communicates over the entire outer periphery of the gas-liquid fluid ejection part, the gas communication part is a gas-liquid fluid ejection part. Compared with the case where it communicates with a part of the outer periphery, the contact area of the gas with respect to the first gas-liquid mixed fluid ejected from the gas-liquid fluid ejecting portion is wide. As a result, a large amount of gas can be mixed or mixed and dissolved in the first gas-liquid mixed fluid supplied to the floating separation tank, and as a result, a large amount of fine bubbles can be generated.

(E) According to the sludge concentration system equipped with the pressurized flotation separator having the above-described effects, the solid recovery rate is improved by the pressurized flotation separator and the use of a polymer flocculant is not required. The concentrated sludge can be composted at compost facilities.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a pressurized flotation separation apparatus according to the present invention will be described with reference to the drawings.
[Embodiment]
FIG. 1 is a schematic explanatory diagram for explaining an embodiment of a sludge concentration system equipped with a pressurized flotation separator according to the present invention.
The sludge concentration system shown in FIG. 1 includes a pressurized flotation separation apparatus 1 indicated by a portion surrounded by a broken line, a wastewater tank 2 and a storage tank 3 in which wastewater to be introduced into the pressurized flotation separation apparatus 1 is stored, and a pressurization A suspension tank (SS) floated and separated by the floating separator 1 is further provided with a separation tank 4 that separates the concentrated sludge into separated water.

  The pressurized flotation separation apparatus 1 is provided in a primary flotation separation tank 5, a secondary flotation separation tank 8, a gas-liquid mixing device 6 indicated by a portion surrounded by a two-dot chain line, and a primary flotation separation tank 5. A fine bubble generating device 7 and a defoaming device 9 are provided.

  Waste water which is treated water is introduced into the primary levitation separation tank 5. The gas-liquid mixing device 6 constitutes a gas-liquid mixing means for obtaining a first gas-liquid mixed fluid to be supplied to the fine bubble generating device 7. The fine bubble generating device 7 is an ejector-type nozzle 71 (hereinafter referred to as “the second gas-liquid mixed fluid”) that can further take in the gas into the first gas-liquid mixed fluid obtained by the gas-liquid mixing device 6. Simply abbreviated as “ejector nozzle”). The fine bubble generator 7 is a device that generates bubbles by supplying the second gas-liquid mixed fluid into the primary levitation separation tank 5.

Hereinafter, each component part of the sludge concentration system provided with the pressurized flotation separation apparatus 1 will be described in detail step by step.
The waste water introduced into the primary levitation separation tank 5 is stored in the waste water tank 2 in advance. And wastewater is sent to the storage tank 3 in the state from which solid content, such as a deposit, was removed by the pumping pump 21 provided in the wastewater tank 2, and is stored temporarily.

  The storage tank 3 is connected to the primary levitation separation tank 5 through a wastewater introduction pipe 31. Reference numeral 312 denotes a connecting portion provided with a flange provided at the proximal end portion of the wastewater introduction pipe 31. A pipe for sending waste water extending from the storage tank 3 is connected to the connecting portion 312. The waste water introduction pipe 31 is provided with a suction pump 32 and a quantitative supply device 33 so that a predetermined amount of waste water is continuously sent to the primary flotation separation tank 5. The tip of the waste water introduction pipe 31 is led out to the inside of the waste water (liquid phase part) put in the primary flotation separation tank 5.

  The primary levitation separation tank 5 has an airtight structure in which the gas phase portion 51 in the tank is blocked or essentially blocked from the outside air. The primary levitation separation tank 5 communicates with the secondary levitation separation tank 8 through a connecting pipe 52. Similarly to the primary levitation separation tank 5, the secondary levitation separation tank 8 also has an airtight structure in which the gas phase portion 81 in the tank is blocked or essentially blocked from the outside air.

  The gas-liquid mixing device 6 is a device for obtaining the first gas-liquid mixed fluid supplied to the fine bubble generating device 7 as described above. The gas-liquid mixing device 6 includes a pressurizing pump 61 that pressurizes and mixes air into the liquid, and an air dissolution tank 62.

The liquid is taken into the pressure pump 61 from the primary levitation separation tank 5 by the water supply pipe 53, and the separated water (treated water) after the separation operation is performed in the primary levitation separation tank 5 is used as the liquid. . The proximal end side of the water supply pipe 53 is provided so as to rise slightly upward from the bottom of the primary levitation separation tank 5 so that the intake port 531 is located slightly above the bottom of the primary levitation separation tank 5. As a result, even if a large solid that cannot be floated and concentrated at the bottom of the primary flotation separation tank 5 is precipitated, the solid is mixed into the pressure pump 61 through the water supply pipe 53. This can prevent the pressurization pump 61 from failing. The separated liquid in which air is pressurized and mixed by the pressure pump 61 passes through the connecting pipe 64 and the air dissolution tank 62 to become a first gas-liquid mixed fluid pressurized to, for example, 3 kgf / cm ² .

  The first gas-liquid mixed fluid is sent from the gas-liquid mixing device 6 through the pressure feed pipe 63 to the fine bubble generating device 7 provided in the primary levitation separation tank 5. Then, after the gas is further taken in by the ejector nozzle 71 to become the second gas-liquid mixed fluid, the first gas-liquid mixed fluid is supplied to the primary levitation separation tank 5 to generate a large amount of fine bubbles. The fine bubbles adhere to suspended substances in the wastewater, and the suspended substances are floated and concentrated by the buoyancy of the attached fine bubbles.

2 is a side view explanatory view showing the fine bubble generating device 7, and FIG. 3 is a bottom view explanatory view of the fine bubble generating device 7 shown in FIG.
With reference to FIG.2 and FIG.3, the structure of the microbubble generator 7 is demonstrated. The fine bubble generating device 7 is provided with a required number (four in this embodiment) of substantially cylindrical ejector nozzles 71 for bubbling the second gas-liquid mixed fluid.

  As shown in FIG. 1, the fine bubble generating device 7 is provided near the bottom in the primary levitation separation tank 5, and the ejection ports of the plurality of ejector nozzles 71 are located on the bottom side so that the bubbles rise from the bottom side. Arranged in a directed state. The ejector nozzle 71 is provided in a state in which the ejection port protrudes from the front end surface 721 of the fine bubble generating device main body 72 to the outside. A pressure feeding pipe 63 to which the first gas-liquid mixed fluid is fed as described above is connected to the base side of the fine bubble generating device main body 72. The fine bubble generator 7 may be installed outside the primary levitation separation tank 5 as long as the second gas-liquid mixed fluid can be supplied to the primary levitation separation tank 5.

  As shown in FIG. 3, the front end surface 721 of the microbubble generator main body 72 is circular in bottom view, and the ejector nozzles 71 are arranged at four equal intervals on the circumference centered on the central portion of the front end surface 721. Has been. Then, the first gas-liquid mixed fluid sent from the pressure feeding pipe 63 shown in FIG. 2 passes through the gas-liquid fluid circulation part 722 of the fine bubble generating device main body 72 in a pressurized state, and is primary from each ejector nozzle 71. It spouts at high speed to the floating separation tank 5 side.

FIG. 4 is an enlarged side sectional view of the ejector nozzle 71 provided in the fine bubble generating device 7 shown in FIG.
The ejector nozzle 71 is formed in a substantially cylindrical shape. The ejector nozzle 71 includes a gas-liquid fluid passage 711 connected to the gas-liquid fluid circulation portion 722 shown in FIG. 2 on the base side (left end side in FIG. 4). The center of the distal end portion of the gas-liquid fluid passage 711 is connected to a gas-liquid fluid ejection hole 712 which is a gas-liquid fluid ejection portion having a base end portion with a hole diameter of about 3 to 10 mm. In the present embodiment, the gas-liquid fluid passage 711 is connected to the gas-liquid fluid ejection hole 712 while maintaining the same inner diameter, but the front side (right side in FIG. 4) is recessed toward the gas-liquid fluid ejection hole 712. It can also be formed in a tapered shape.

  As described above, the base side (left side in FIG. 4) of the gas-liquid fluid ejection hole 712 has a hole diameter of about 3 to 10 mm, but the front side (right side in FIG. 4) has a hole diameter of about 5 to 12 mm. A jet expansion portion 713 that is wider than the liquid fluid jet hole 712 is formed. The jet expansion part 713 constitutes a mixing part that mixes or mixes and dissolves air sucked from a gas communication path 715 described later and a first gas-liquid mixed fluid jetted from the gas-liquid fluid passage 711.

  And the jet expansion part 713 which is the front part side of the gas-liquid fluid jet hole 712 is connected with the bubble jet hole 714 which is a bubble jet part provided in the front part side of the ejector nozzle 71. The bubble ejection hole 714 is formed in a tapered shape so that its inner diameter expands from the ejection expansion portion 713 toward the tip side, and ejects fine bubbles into the primary levitation separation tank 5.

  In the middle of the gas-liquid fluid ejection hole 712, there is a gas communication path 715 which is a gas communication means for communicating the gas sucked into the first gas-liquid mixed fluid by the negative pressure generated by the ejection of the first gas-liquid mixed fluid. It is connected. The gas communication path 715 is connected to an air circulation pipe 716 that is an air circulation portion led out of the ejector nozzle 71.

  As shown in FIG. 3, the tip of the air flow pipe 716 is connected to the gas communication path 715 of each ejector nozzle 71. The proximal end side of the air circulation pipe 716 is connected to the other air circulation pipe 716 and is connected to the distal end portion of the ventilation pipe 73 that is an air ventilation section guided from the outside of the fine bubble generating device main body 72. . The base end side of the vent pipe 73 is led out of the primary levitation separation tank 5 shown in FIG. 1 and communicates with the outside air.

  As shown in FIG. 4, the gas communication path 715 of the ejector nozzle 71 includes a space portion 718 that communicates with the entire outer periphery of the gas-liquid fluid ejection hole 712. The space portion 718 is a space having a circular shape when viewed from the front and having a required thickness (for example, about 5 mm) in the flow direction of the first gas-liquid mixed fluid. The communication portion 717 of the space portion 718 that communicates with the gas-liquid fluid ejection hole 712 includes a gap that is narrower than the thickness of the space portion 718 of about 5 mm. The communication part 717 is connected to an ejection expansion part 713 that is slightly wider than the base part side of the gas-liquid fluid ejection hole 712 described above.

FIG. 5 is an enlarged cross-sectional explanatory view schematically showing a generation mechanism of fine bubbles generated from the ejector nozzle 71.
With the above configuration, the first gas-liquid mixed fluid mixed by the gas-liquid mixing device 6 shown in FIG. 1 is introduced into the fine bubble generating device 7 in a pressurized state and sent to the ejector nozzle 71. The first gas-liquid mixed fluid sent to the ejector nozzle 71 shown in FIG. 5 is ejected from the gas-liquid fluid ejection hole 712 through the gas-liquid fluid passage 711 at a high speed.

  A negative pressure (low pressure) is generated in the vicinity of the outlet of the gas-liquid fluid ejection hole 712 due to the high-speed ejection of the first gas-liquid mixed fluid, and air is sucked from the gas communication path 715 to the ejection expansion portion 713 by this negative pressure. As a result, air is further taken into the first gas-liquid mixed fluid to become the second gas-liquid mixed fluid. Further, the second gas-liquid mixed fluid in which a large amount of air is mixed or dissolved is discharged from the bubble expansion hole 713 into the wastewater in the primary levitation separation tank 5 through the bubble expansion hole 714. Thus, the pressurized second gas-liquid mixed fluid is released to the primary levitation separation tank 5 to be in a pressure drop state (released from the pressurized state), and generates a large amount of fine bubbles.

Although the detailed mechanism of the generation of fine bubbles is not clear, it can be considered as follows.
That is, the first gas-liquid mixed fluid A is ejected from the gas-liquid fluid ejection hole 712 in the straight direction. Due to the jet of the first gas-liquid mixed fluid, the backflow water B flows back into the ejector nozzle 71 from the primary floating separation tank 5 side along the inner wall of the bubble ejection hole 714.

  Then, the air C sucked in a high speed state through the narrow communication portion 717 of the gas communication path 715 is surrounded by the first gas-liquid mixed fluid A around the jet flow of the gas-liquid fluid jet holes 712. It will be dragged into 714. The air C is sucked between the first gas-liquid mixed fluid A and the backflow water B described above, and the air C is caused by friction between the jet of the air C and the jet of the first gas-liquid mixed fluid A. Shears and a lot of finer bubbles are generated.

  Moreover, as described above, the primary levitation separation tank 5 shown in FIG. 1 has an airtight structure in which the gas phase portion 51 in the tank is blocked or essentially blocked from the outside air, and thus is open to the outside air. Unlike the conventional levitation separation tank, the bubbles that have floated from the liquid level of the wastewater to the gas phase portion 51 do not escape to the outside air, and the pressure in the gas phase portion 51 is higher than the atmospheric pressure (outside air). To be kept. As a result, the hydraulic pressure in the wastewater is also higher than the normal hydraulic pressure (the wastewater hydraulic pressure when the floating separation tank is open to the outside air). Then, the pressurized second gas-liquid mixed fluid is released into the waste water in the floating separation tank 5 and becomes a pressure drop state and becomes a bubble, but as described above, it is higher than the normal hydraulic pressure. Since bubbles are formed under a high pressure state, bubbles that are finer than bubbles generated in a floating separation tank under atmospheric pressure are generated.

  In addition, after the occurrence, the fine bubbles that float in the primary levitation separation tank 5 are placed under a pressure higher than the normal hydraulic pressure, so that they do not become larger as they rise, and the size is essentially reduced. Ascend while maintaining.

  In this way, the airtight structure of the fine bubble generating device 7 and the primary levitation separation tank 5 can generate a large amount of finer bubbles, so that even small solid particles that have been difficult to be floated and concentrated by the conventional method can be obtained. It can be floated and concentrated. As a result, since the solid content recovery rate is improved, it is not necessary to use a polymer flocculant, and the concentrated sludge after separation can be composted in a compost facility or the like. In addition, by generating finer bubbles, the amount of water adhering to the bubbles is reduced, and a decrease in the solid content concentration can be prevented.

Please refer to FIG.
The suspended matter floated and separated on the water surface by the fine bubbles is collected by an inverted conical mud collector 54 disposed near the water surface. Then, it is sent to the defoaming device 9 through the discharge pipe 541. The defoaming device 9 has a rotating shaft 92 provided with a required number of stirring blades 91. Then, by rotating the stirring blade 91 by a power source such as a motor, the fine bubbles contained in the suspended substance are physically destroyed and defoamed. Reference numeral 94 denotes a pressure adjusting valve for adjusting the internal pressure of the gas phase part 51 of the primary levitation separation tank 5 and the gas phase part 81 of the secondary levitation separation tank 8 described later.

  As described above, the primary levitation separation tank 5 is communicated with the secondary levitation separation tank 8 by the connecting pipe 52. Then, the separation water after the separation operation is performed in the primary levitation separation tank 5 is sent from the connection pipe 52. The base end side of the connecting pipe 52 is connected to a position lower than the lower surface of the primary levitation separation tank 5 so that the suspended substance separated in the primary levitation separation tank 5 does not flow into the secondary levitation separation tank 8.

  Further, a part of the fine bubbles generated from the fine bubble generating device 7 flows into the secondary floating separation tank 8 together with the separation water into the connecting pipe 52. Thereby, the floating separation of the suspended matter by the fine bubbles is also performed on the secondary floating separation tank 8 side. The leading end of the connecting pipe 52 is introduced to the bottom side of the secondary levitation separation tank 8 so that the fine bubbles float from the bottom side of the secondary levitation separation tank 8. Further, the separated water (treated water) after the separation operation is performed in the secondary levitation separation tank 8 is discharged to the outside through the discharge pipe 83. A connecting portion 831 having a flange is provided at the tip of the discharge pipe 83, and a pipe (not shown) for sending to a tank or the like for storing separated water is connected to the connecting portion 831.

  Similarly, an inverted conical mud collector 82 is provided on the water surface of the secondary flotation separation tank 8. The discharge pipe 821 led out from the mud collector 82 is connected to the discharge pipe 541 on the primary levitation separation tank 5 side, and is connected to the defoaming device 9 described above.

  In this embodiment, the fine bubble generator 7 is not provided on the secondary levitation separation tank 8 side. However, depending on the processing capacity of the primary levitation separation tank 5, the fine bubble generator is also provided on the secondary levitation separation tank 8 side. 7 may be provided.

  The suspended substance treated by the defoaming device 9 is sent to the separation tank 4 through the discharge pipe 93. The separation tank 4 is further divided into an upper layer of concentrated sludge and a lower layer of separated water, and the concentrated sludge is composted at an existing compost facility or the like. Reference numeral 931 indicates a connection portion 931 having a flange provided at the tip of the discharge pipe 93, and a pipe extending from the separation tank 4 is connected to the connection portion 931.

  Note that a drain pipe 502 including an on-off valve 501 is connected to the primary levitation separation tank 5. Similarly, a drain pipe 802 including an on-off valve 801 is connected to the secondary levitation separation tank 8. Each drain pipe 502 and 802 is connected to a connecting pipe 503. A connecting portion 504 having a flange is provided at the distal end portion of the connecting pipe 503, and a drain pipe (not shown) is connected to the connecting portion 504.

[Example]
6 to 9 are explanatory diagrams when the pressurized levitation separator 1 shown by a portion surrounded by a broken line in FIG. 1 is configured as an integral type.
FIG. 6 is a front view explanatory view showing the pressurized flotation separation apparatus 1,
FIG. 7 is an explanatory diagram in plan view of the pressurized levitation separator 1 shown in FIG.
FIG. 8 is a rear view explanatory view of the pressurized levitation separator 1 shown in FIG.
FIG. 9 is a left side explanatory view of the pressurized levitation separator 1 shown in FIG.

  Since the operation of each component of the pressurized levitation separator 1 shown in FIGS. 6 to 9 has already been described with reference to FIG. 1, the description thereof is omitted here. 6 to 9 are denoted by the same reference numerals as those in FIG. In addition, the left-right direction and the front / rear direction of the pressure levitation separator 1 shown in the present embodiment are described based on FIG.

Hereinafter, the pressurized levitation separator 1 will be described with reference to FIG. 1 and FIGS. 6 to 9.
The size of the pressure levitation separator 1 is about 1460 mm in width, 1650 mm in height, and about 750 mm in depth in FIG. This size is merely an example, and is set as appropriate according to the required wastewater treatment capacity.

  The pressurized flotation separation apparatus 1 includes a base member 10 on which the primary flotation separation tank 5 and the secondary flotation separation tank 8 are placed. As shown in FIG. 7, the base member 10 includes a top plate 101 having a rectangular shape in plan view on the upper surface thereof. On the top plate 101, a primary levitation separation tank 5 and a secondary levitation separation tank 8 having a circular shape in plan view and shaped like a barrel are arranged side by side.

  As shown in FIG. 6, above the primary levitation separation tank 5 and the secondary levitation separation tank 8, a front side of a wastewater introduction pipe 31 having a quantitative supply device 33 extending in the left-right direction is disposed. As shown in FIG. 9, the distal end side of the waste water introduction pipe 31 is introduced into the waste water in the primary levitation separation tank 5 with the introduction port 311 facing downward.

  Further, as shown in FIG. 6, the base side (the right end side in FIG. 6) of the waste water introduction pipe 31 is bent downward, and then enters the base member 10 through the back side of the secondary levitation separation tank 8, Further, as shown in FIG. 7, the base member 10 is bent in the horizontal direction on the bottom side, and finally protrudes outward from the left side surface portion of the base member 10. And the connection part 312 provided with the flange in the protrusion part is provided, and piping (illustration omitted) for sending the wastewater extended from the wastewater tank 2 or the storage tank 3 is connected to this connection part 312.

  The pressurization pump 61 and the air dissolution tank 62 constituting the gas-liquid mixing device 6 are accommodated in the base member 10. A water supply pipe 53 that sends separated water from the primary levitation separation tank 5 to the lower pressure pump 61 and a connection pipe 64 that connects the pressure pump 61 and the air dissolution tank 62 are also accommodated in the base member 10.

  The pressure feed pipe 63 for sending the first gas-liquid mixed fluid from the air dissolution tank 62 to the primary levitation separation tank 5 is located between the primary levitation separation tank 5 and the secondary levitation separation tank 8 from above the base member 10 (FIGS. 7 and 9). (Refer to above) and further led out from the ceiling of the primary levitation separation tank 5 into the primary levitation separation tank 5. And the fine bubble generator 7 shown in FIG. 2 is connected to the front end side of the pressure feeding pipe 63.

  A discharge pipe 541 (see FIG. 7) for discharging the suspended solids separated in the primary levitation separation tank 5 to the defoaming device 9 is the length direction of the base member 10 from the front side of the primary levitation separation tank 5 (right in FIG. 7). Direction) and is connected to the front side of the defoaming device 9 after being bent at an angle of about 90 degrees.

  The defoaming device 9 is arranged in a front side adjacent space S (see FIG. 7) sandwiched between the primary levitation separation tank 5 and the secondary levitation separation tank 8. Similarly, the discharge pipe 821 for discharging the suspended matter separated in the secondary levitation separation tank 8 is also about 90 degrees from the front side of the secondary levitation separation tank 8 in the length direction of the base member 10 (left direction in FIG. 7). After being bent at an angle of, it is connected to the front side of the defoaming device 9.

  The defoaming device 9 is provided with a pressure adjusting valve 94. A discharge pipe 93 (see FIG. 1) for discharging suspended substances treated by the defoaming device 9 enters the base member 10 from the lower part of the defoaming device 9 and is further horizontal on the ceiling side in the base member 10. It is bent in the direction (left direction) and finally protrudes outward from the left side surface portion of the base member 10. And the connection part 931 provided with the flange in the protrusion part is provided, and piping (illustration omitted) for discharging the suspended solids extended from the separation tank 4 grade | etc., Is connected to this connection part 931.

  The discharge pipe 83 for discharging the separated water obtained in the secondary levitation separation tank 8 extends downward from the front side of the secondary levitation separation tank 8 and enters the base member 10, and further on the bottom side in the base member 10. Is bent in the horizontal direction (left direction) and finally protrudes outward from the left side surface portion of the base member 10. And the connection part 831 provided with the flange in the protrusion part is provided, and piping (illustration omitted) for sending to the tank etc. which store separation water in this connection part 831 is connected.

  As shown in FIG. 8, a drain pipe 502 having an on-off valve 501 is connected to the back side of the primary levitation separation tank 5. Similarly, a drain pipe 802 including an on-off valve 801 is connected to the back side of the secondary levitation separation tank 8. Each drain pipe 502 and 802 is connected to a connecting pipe 503. The connecting pipe 503 extends downward and enters the base member 10, and is bent twice in the L shape on the bottom side in the base member 10. Finally, the connection pipe 503 is substantially centered on the left side surface of the base member 10 (FIG. 7). (See below). And the connection part 504 provided with the flange in the protrusion part is provided, and piping for drainage (illustration omitted) is connected to this connection part 504.

  As shown in FIG. 8, a control panel 102 that controls each pump of the pressurized levitation separator 1 is accommodated in the base member 10. The pressure levitation separator 1 can be switched between automatic operation and manual operation by the control panel 102.

(Experimental example)
Using the pressurized flotation separation apparatus 1 shown in FIG. 6, activated sludge generated from a manure storage facility in a livestock house was levitated and concentrated, and the water quality of the waste water before treatment and the separated liquid after treatment was examined. Table 1 below shows the results of the water quality test and the removal rate (%) calculated from the analysis results.

  As is clear from the results in Table 1, it can be seen that the activated sludge can be concentrated and separated with a very high removal rate.

  Note that the terms and expressions used in this specification are merely explanatory and are not restrictive, and do not exclude terms and expressions equivalent to the above terms and expressions. The present invention is not limited to the illustrated embodiment, and various modifications can be made within the scope of the technical idea.

  Further, in the claims, the reference numerals used in the drawings are described in parentheses in order to facilitate understanding of the contents of the claims, but the claims are not limited to those described in the drawings. Absent.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic explanatory drawing for demonstrating embodiment of the sludge concentration system provided with the pressurized flotation separation apparatus which concerns on this invention. Side view explanatory drawing which shows the microbubble generator 7. FIG. The bottom view explanatory drawing of the microbubble generator 7 shown in FIG. The side view sectional drawing to which the ejector nozzle 71 provided in the microbubble generator 7 shown in FIG. 2 was expanded. Explanatory cross-sectional explanatory drawing which shows typically the generation | occurrence | production mechanism of the fine bubble generated from the ejector nozzle 71. FIG. Front view explanatory drawing which shows the pressurization floating separator 1. FIG. FIG. 7 is a plan view explanatory diagram of the pressure levitation separator 1 shown in FIG. 6. FIG. 7 is a rear view explanatory view of the pressurized flotation separation apparatus 1 shown in FIG. 6. FIG. 7 is a left side explanatory view of the pressurized flotation separation apparatus 1 shown in FIG. 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure levitation separator 2 Wastewater tank 3 Storage tank 4 Separation tank 5 Primary levitation separation tank 6 Gas-liquid mixing device 7 Fine bubble generator 8 Secondary levitation separation tank 9 Defoaming device 10 Base member 21 Lifting pump 31 Wastewater introduction pipe 32 Suction pump 33 Metering feeder 51 Gas phase section 52 Connection pipe 53 Water supply pipe 54 Mud collector 61 Pressure pump 62 Air dissolution tank 63 Pressure feed pipe 64 Connection pipe 71 Ejector nozzle 72 Fine bubble generator main body 73 Vent pipe 81 Gas phase Part 82 Mud collector 83 Discharge pipe 91 Stirrer blade 92 Rotating shaft 93 Discharge pipe 94 Pressure adjustment valve 101 Top plate 102 Control panel 311 Inlet 312 Connection part 501 Open / close valve 502 Drain pipe 802 Drain pipe 503 Connection pipe 504 Connection part 531 Inlet 541 Discharge pipe 711 Gas-liquid fluid passage 712 Gas-liquid fluid ejection hole 713 Ejection expansion part 714 Bubble ejection hole 715 Gas communication path 16 air flow pipe 717 communicating portion 718 space 721 distal surface 722 gas-liquid fluid circulation portion 801 closing valve 802 drain pipe 821 discharging pipe 831 connecting portions 931 connecting portions A primary gas-liquid mixed fluid B backflow water C air S adjacent space

Claims (6)

A pressure flotation separation apparatus for wastewater treatment,
The gas phase section (51) in the tank is provided with a floating separation tank (5) configured to be in an airtight state in which the outside air is blocked or essentially blocked,
Pressure floating separator. A pressure flotation separation apparatus for wastewater treatment,
A floating separation tank (5) configured to be in an airtight state in which the gas phase part (51) in the tank is blocked or essentially blocked from outside air,
In the levitation separation tank (5), it is configured so that bubbles are generated under the gas phase part (51) in a pressure state higher than atmospheric pressure,
Pressure floating separator. A gas-liquid mixing means (6) for mixing a gas in a liquid under pressure to obtain a first gas-liquid mixed fluid;
A fine bubble generator (7) for generating bubbles by supplying a second gas-liquid mixed fluid into the floating separation tank (5);
With
The fine bubble generating device (7) is provided with an ejector-type nozzle (71) capable of further incorporating gas into the first gas-liquid mixed fluid obtained by the gas-liquid mixing means (6). Features
The pressurized flotation separator according to claim 1 or 2. The ejector-type nozzle (71) has a gas-liquid fluid ejection part (712) for ejecting the first gas-liquid mixed fluid and a negative pressure generated by the ejection of the first gas-liquid mixed fluid to the first gas-liquid mixed fluid. A gas communication part (715) for communicating the sucked gas,
The gas communication part (715) includes a space part (716) communicating over the entire outer periphery of the gas-liquid fluid ejection part (712),
The pressurized flotation separator according to claim 3. A floating separation device (1) according to claim 1, 2, 3 or 4,
Sludge concentration system. A pressure flotation separation method in wastewater treatment,
By blocking or essentially blocking the gas phase part in the levitation separation tank from outside air to make it airtight, the inside of the levitation separation tank is under the gas phase part (51) in a pressure state higher than atmospheric pressure. It is characterized by generating bubbles with
Pressure floating separation method.

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