JP2003320390A - Wastewater treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the outflow of a carrier (granule) losing sedimentation properties. <P>SOLUTION: A methane formentation tank 1 is constituted so that organic matter in wastewater is decomposed into methane, carbon dioxide and water by the action of anaerobic microorganisms and a partition wall 3 is arranged in a tank body 1A to form a reaction tank 4 and a separation tank 5 separately in a communicable manner. The tank body 1A has a carrier stationarily holding layer 2, wherein a necessary minimum holding amount of granules formed by the self-granulation of anaerobic microorganisms is stationarily held, provided on the bottom part thereof and is equipped with a supply part for supplying wastewater into the carrier stationarily holding layer 2 and a gas discharge part for discharging methane and carbon dioxide from an upper part. The separation tank 5 has a treated water discharge part for discharging treated water being wastewater after decomposition treatment from an upper part, and a stirring means (stirring blades 9 and a motor 10) for separating air bubbles adhering to or enclosed in floating granules is provided to the reaction tank 4. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a carrier (hereinafter referred to as a granule) in which an anaerobic microorganism is self-granulated.
The present invention relates to a wastewater treatment device that decomposes organic matter in wastewater into methane, carbon dioxide, and water, and particularly relates to a technique for preventing outflow of granules.

[0002]

2. Description of the Related Art Conventionally, waste water is circulated in an upward flow in a treatment tank filled with granules to remove organic matter in the waste water from methane (CH ₄ ), carbon dioxide (CO ₂ ), water (H _2
2 O) UASB (Upflow Anaerobic Slud)
ge Blanket) Wastewater treatment equipment is known. In the UASB wastewater treatment device, granules, wastewater after decomposition treatment (hereinafter referred to as treated water), methane and carbon dioxide are efficiently separated in the three-phase separation section above the treatment tank, and the treated water is discharged. The UASB wastewater treatment device has a significantly lower power consumption than the aerobic activated sludge treatment device and is excellent in that methane gas can be recovered as energy such as fuel.

In the conventional UASB wastewater treatment equipment, there is a risk that the granules lose their sedimentation property and flow out. There are various factors in the outflow of granules, but for example, by encapsulating or adhering methane and carbon dioxide (bubbles) generated by the decomposition process, the granules float up,
A typical factor is that solid-liquid separation in the three-phase separation section becomes insufficient and flows out together with the treated water. The following techniques have been proposed to prevent such outflow of granules. That is, Japanese Unexamined Patent Publication No. 5-123692 (Prior Art 1) discloses a technique in which a screen of long fiber bundles is provided in the upper part of a processing tank and granules are filtered here. Further, Japanese Unexamined Patent Publication No. 10-216784 (Prior Art 2) discloses a technique of providing a separation tank for separating the granules discharged from the processing tank.

[0004]

However, each of the conventional UASB wastewater treatment devices has the following problems. That is, in Prior Art 1, the granules captured on the screen are blown off by the cleaning blower, but it is difficult to confirm the cleaning state in the closed processing tank, and the screen is reliably clogged. Cannot be prevented. On the other hand, in the prior art 2, although the outflowing granules are precipitated and separated, it is doubtful whether the floatable granules will settle. In addition, proposals on the theme of gas / solid / liquid separation have been made in JP-A-11-128979 and JP-A-5-123691, but it is possible to reliably separate the floating granules by bubbles. First, there were no successful cases of preventing granule spills.

In view of the conventional problems as described above, the present invention agitates the floating granules to separate air bubbles that adhere to or are contained in the granules, thereby improving the sedimentation property of the granules. By recovering
It is an object of the present invention to provide a wastewater treatment device that prevents the outflow of granules.

[0006]

Therefore, according to the invention of claim 1, there is provided a wastewater treatment apparatus for decomposing organic matter in wastewater into methane and carbon dioxide by the action of anaerobic microorganisms,
A carrier stationary holding layer for allowing the anaerobic microorganism to stand the minimum required amount of the carrier self-granulated, and a bubble located above the carrier stationary holding layer and attached to or contained in a floating carrier are separated. A reaction tank equipped with a stirring means, which discharges methane and carbon dioxide decomposed by the anaerobic microorganisms, communicates with the lower part of the reaction tank, and the waste water after decomposition treatment and the carrier introduced from the lower part of the reaction tank And a separation tank for discharging the wastewater after the decomposition treatment from the upper part and allowing the carrier to settle to the lower part to separate the wastewater after the decomposition treatment from the carrier by flowing in an upward flow. Is characterized by.

According to such a structure, the wastewater supplied to the carrier stationary holding layer is decomposed into methane, carbon dioxide and water by the action of the carrier stationary. At this time, the carrier in which bubbles adhere or are included and lose the sedimentation property rises in the reaction tank. With respect to the carrier rising in the reaction tank, the bubbles adhering to or contained in the carrier are separated by the stirring means, the sedimentation property is recovered, and the carrier returns to the carrier stationary holding layer. On the other hand, in the carrier introduced into the separation tank from the lower part of the reaction tank, bubbles are separated in the ascending process, the settling property is recovered, and the carrier returns to the carrier stationary holding layer. Therefore, the carrier is less likely to be discharged together with the treated water, and the carrier is prevented from flowing out. Further, since the wastewater and the carrier are positively stirred and mixed, the reaction speed is increased and an efficient treatment effect is obtained.

According to the second aspect of the present invention, a partition is provided between the reaction tank and the separation tank, the lower end of the partition has a gap with the upper surface of the carrier stationary holding layer, and the upper end of the partition. Is characterized by being formed higher than the liquid level in the reaction tank. According to this configuration, the partition wall allows the reaction tank and the separation tank to be easily communicated with each other, and the upper end of the partition wall is formed higher than the liquid level in the reaction tank, so that the influence of stirring in the reaction tank is affected. Stable carrier sedimentation is performed without reaching the separation tank.

According to the third aspect of the present invention, a partition is provided between the reaction tank and the separation tank, and the lower end of the partition projects into the carrier stationary holding layer, while the upper end of the partition reacts. It is formed higher than the liquid level in the tank, and at a predetermined distance from the inner peripheral surface of the lower portion of the reaction tank, the waste water introduced from the lower part of the carrier stationary holding layer is passed through the carrier stationary holding layer to the reaction tank. It is characterized in that it is provided with a cylindrical tube portion that leads to.

According to this structure, the wastewater introduced from the lower portion of the carrier stationary holding layer is decomposed into methane, carbon dioxide and water by the action of the carrier stationary. At this time, since the cylindrical portion that guides the wastewater to the reaction tank through the carrier stationary holding layer is provided, the carrier that loses the sedimentation property due to the attachment or inclusion of bubbles is suppressed from being introduced into the separation tank. As a result, most of it is introduced into the reaction tank. For this reason, the carrier, which has lost its sedimentation property due to the bubbles, is separated into bubbles in the reaction tank and the separation tank, respectively, so that it is significantly reduced that the carriers are not able to be separated and flow out to the outside. Further, unreacted wastewater is prevented from being introduced into the separation tank.

In the invention according to claim 4, the reaction tank is
It is characterized by comprising at least one of a mechanical stirring means for stirring by an object and a fluid stirring means for stirring by injecting a fluid into the reaction tank. According to such a configuration, the mechanical stirring means or the fluid stirring means effectively separates the bubbles adhering to or contained in the floating carrier, thereby reliably recovering the sedimentation property of the carrier. Further, since the wastewater and the carrier are positively stirred and mixed, the reaction speed is increased and an efficient treatment effect is obtained.

In the invention according to claim 5, the fluid type stirring means compresses methane and carbon dioxide recovered from the reaction tank and jets them upward from above the carrier stationary holding layer of the reaction tank. It is characterized in that it is configured to include a gas ejection means. According to this structure, the carrier floating on the liquid surface is hit by the jetted fluid to separate the air bubbles and recover the sedimentation property. In addition, the methane and carbon dioxide generated in the reaction tank can be effectively used.

In the invention according to claim 6, the fluid-type stirring means pressurizes the wastewater after the decomposition treatment recovered from the separation tank and jets it downward from the upper part of the liquid level in the reaction tank. It is characterized in that it is configured to include. According to this structure, the carrier floating on the liquid surface is hit by the jetted fluid to separate the air bubbles and recover the sedimentation property. In addition, it is possible to effectively use the waste water recovered from the separation tank after the decomposition treatment.

According to a seventh aspect of the present invention, the separation tank is provided with an inclined solid-gas liquid separation plate for separating a solid-liquid liquid composed of a carrier, a gas composed of methane and carbon dioxide, and waste water after decomposition treatment. It is characterized by being done. According to this structure, when the treated water flows along the solid-gas liquid separation plate provided in the separation tank, the carrier descends along the upper side of the solid-liquid separation plate, and only the treated water is solid-liquid separation plate. Since it rises along the lower side, solid-liquid separation of the carrier, gas, and treated water is more reliably performed.

In the invention according to claim 8, in the separation tank, a labyrinth passage is formed by a plurality of inclined separation plates whose upper part is closed in order to separate the waste water after the decomposition treatment and the carrier. Characterize. According to such a configuration, when the treated water flows through the labyrinth passage formed in the separation tank, the carrier descends along the plurality of separation plates forming the labyrinth passage, and only the treated water rises. The solid-liquid separation between the carrier and the carrier is performed more reliably.

According to a ninth aspect of the present invention, the separation tank includes an inclined solid-gas liquid separation plate which is spaced from the peripheral wall thereof, and bubbles and bubbles which are located above the solid-liquid separation plate. And a gas-liquid separation plate for trapping the carrier whose specific gravity has become lighter, and returning the trapped air bubbles and the carrier whose specific gravity has become lighter to the reaction tank.

According to this structure, when the treated water flows along the solid-gas liquid separation plate provided in the separation tank, the carrier descends along the upper side of the solid-liquid separation plate and contains bubbles and bubbles. The treated water containing the carrier (herein, referred to as air bubbles) whose specific gravity has become lighter rises along the lower side of the solid-gas liquid separation plate.
Then, air bubbles and the like contained in the treated water are returned to the reaction tank after being trapped by the gas-liquid separation plate. Therefore, it is possible to prevent the carrier, which contains bubbles and has a low specific gravity, from being discharged to the outside, and effectively prevent the carrier from flowing out.

In a tenth aspect of the present invention, the gas-liquid separation plate includes a first inclined plate inclined downward from the partition between the reaction tank and the separation tank toward the separation tank toward the outer wall. A second inclined plate inclined downward from the partition wall toward the reaction tank toward the center, and a lower end of the first inclined plate is lower than a lower end of the second inclined plate, and The partition is characterized in that an opening is provided at a position lower than the upper end of the second inclined plate and higher than the lower end thereof.

According to this structure, the gas-liquid separating plate traps the bubbles and the carrier having a low specific gravity by containing the bubbles and returning the trapped bubbles and the carrier having a low specific gravity by containing the bubbles to the reaction tank. Easy to configure. Claim 11
In the invention described above, the bottom surface of the carrier stationary holding layer is formed into an inclined surface whose cross-sectional area gradually decreases as it goes downward.

According to this structure, the carrier whose settling property is recovered in the reaction tank or the separation tank is collected by the inclined surface in the substantially central portion of the carrier stationary holding layer. Therefore, the wastewater is
Since it is introduced into a region where the carrier density is high, the anaerobic microorganisms effectively decompose organic substances. In the invention according to claim 12, in the upper part of the separation tank, there is provided a carrier trap means for trapping a bubble and a carrier having a low specific gravity by containing the bubble and releasing only the trapped bubble to the upper part of the separation tank. Is characterized by.

According to such a structure, the carrier and the air bubbles whose air bubbles cannot be separated in the reaction tank and the separation tank are trapped by the carrier trap means. Then, only the trapped bubbles are guided to the upper part of the separation tank. For this reason,
Even if the air bubbles cannot be separated, they are prevented from flowing out. In a thirteenth aspect of the present invention, the carrier stationary holding layer is provided below the carrier stationary holding layer with fluid ejecting means for ejecting a fluid upward from the lower portion.

According to this structure, the fluid jetting means is activated at regular time intervals to jet the fluid upward from the lower part of the carrier stationary holding layer, whereby the carrier stationary holding layer is allowed to stand still. The active carrier is stirred and floated to give the activity.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an overall configuration of a methane fermentation tank equipped with a wastewater treatment device according to the present invention as a first embodiment of the present invention. The methane fermenter 1 converts organic matter in wastewater from factories into CH ₄ (methane) and C by the action of anaerobic microorganisms.
It decomposes into O ₂ (carbon dioxide) and H ₂ O (water). Then, the wastewater is supplied to an acid production tank (not shown) to form raw water mainly containing acetic acid, and the raw water is introduced from the acid production tank to the methane fermentation tank 1.

The tank body 1A of the methane fermentation tank 1 is composed of a circular top plate 1a, a cylindrical side plate 1b, and a circular bottom plate 1c, and the minimum required granules self-granulated by anaerobic microorganisms. A carrier stationary holding layer 2 that holds the held amount is provided at the bottom, a supply unit that supplies waste water into the carrier stationary holding layer 2, and a gas discharge unit that discharges methane and carbon dioxide from the upper portion. Is equipped with. In addition, the carrier stationary holding layer 2
Above the above, a reaction tank 4 and a separation tank 5 which are partitioned into a double structure inside and outside by a partition 3 having a substantially cylindrical shape and which can communicate with each other are provided. The lower end portion of the partition wall 3 has a gap with the bottom plate 1c, and the upper end portion of the partition wall 3 is formed higher than the liquid level in the reaction tank 4 and spaced from the top plate 1a. And
The separation tank 5 is provided with a treated water discharge part for discharging treated water, which is waste water after decomposition treatment, from above.

The supply part comprises an annular pipe 6 and a raw water introduction pipe 7. In this case, in the lower part of the carrier stationary holding layer 2,
An annular pipe 6 is provided, a plurality of raw water supply holes 6A are formed in the peripheral wall of the annular pipe 6, and a raw water introducing pipe 7 is connected to the annular pipe 6. On the other hand, the gas discharge part is composed of a gas discharge pipe 8, and the gas discharge pipe 8 is connected in communication with the top plate 1a.

Here, the reaction tank 4 is provided with a mechanical stirring means as a stirring means for separating air bubbles attached to or contained in the floating granules. The mechanical stirring means includes a stirring blade 9 and a motor 10 which is a rotation driving device for the stirring blade 9.
And are included. The stirring blade 9 is a rotary drive shaft 9A.
And a plurality of blades 9B radially fixed to the outer periphery of the blade 9B.
And consists of. In the present embodiment, the blades 9B and 9C are fixed at two positions in the axial direction of the rotary drive shaft 9A so that the adjacent blades have different phases. The upper end of the rotation drive shaft 9A is connected to the motor 10 attached to the top surface of the top plate 1a.

On the other hand, in the lower part of the separation tank 5, there is provided a solid-gas separation plate 11 for separating a solid-gas liquid composed of a gas composed of granules, methane and carbon dioxide and treated water. In the solid-gas liquid separation plate 11, the granules descend along the upper side thereof and only the treated water rises along the lower side thereof,
In order to promote solid-liquid separation, it is composed of a plurality of inclined plate members. In this case, as shown in FIG. 2, first and second solid-gas liquid separation plates 11A and 11B are provided, and the first solid-gas liquid separation plate 11A includes the outer peripheral surface of the partition wall 3 and the tank main body 1A. A large number of rows are provided in a row in the circumferential direction at intervals with the circumferential surface. The second solid-gas liquid separation plate 11B is formed below the first solid-gas liquid separation plate 11A in the same tilt direction as the first solid-gas liquid separation plate 11A. A plurality of gas-liquid separation plates 11A are arranged in a row in the circumferential direction at intervals while having a slight deviation from the extending direction. The solid-gas liquid separation plate 11 may be composed of at least one plate-shaped member.

A trough-shaped member 12 for receiving and discharging treated water is provided above the separation tank 5, one end of which is fixed to the inner peripheral surface of the side plate 1b and the other end of which extends upward. An L-shaped gutter-shaped member 12 is provided in an annular shape. The gutter-shaped member 1
Below 2 is provided a separation plate 13 for solid-liquid separation of treated water and granules. The separation plate 13 is composed of a plurality of inclined plate members whose granules descend along the upper side thereof and only treated water rises along the lower side thereof.
In this case, as shown in FIG. 1, the labyrinth passage 14 is formed by the inclined first and second separation plates 13A and 13B whose upper portions are closed. That is, the first separation plate 13
A is formed in a conical surface centered on the central axis of the methane fermentation tank 1 and is provided on the outer peripheral surface of the partition wall 3, and the second separation plate 1
3B is formed in the shape of an inverted conical surface centered on the central axis of the methane fermentation tank 1, and the inner peripheral surface thereof is provided so as to face the tip of the first separating plate 13A. It is provided. The separation plate 13 may be composed of at least two plate members.

The treated water discharge section comprises a treated water discharge pipe 15. That is, the treated water discharge pipe 15 discharges the treated water received by the gutter-shaped member 12 to the outside, and is connected to the side plate 1b corresponding to the inside of the gutter-shaped member 12. Next, the operation of the methane fermentation tank 1 having such a configuration will be described. The raw water (organic wastewater) supplied from the acid generation tank into the carrier stationary holding layer 2 is raised by the granules that are allowed to stand in the carrier stationary holding layer 2 when rising in the carrier stationary holding layer 2.
The contained organic matter is decomposed into treated water, and the treated water is accompanied by the rise of the anaerobic gas (methane and carbon dioxide) generated by the decomposition and is accompanied by some granules in the reaction tank 4 and the separation tank 5. Part of the generated anaerobic gas is collected at the top of the methane fermentation tank 1, that is, inside the top plate 1a, and is discharged to the outside from a gas discharge pipe 8 connected to communicate with the top. The discharged anaerobic gas is introduced into a boiler or the like and burned, for example.

In this case, by disposing the mechanical stirring means having the stirring blade 9 in the reaction tank 4, the plurality of blades 9B and 9C are driven to rotate by the driving of the motor 10, so that the reaction tank 4 Bubbles attached to or contained in the floating granules are separated, the settling property of the granules is restored, and the granules quickly settle in the carrier stationary holding layer 2.

The blades 9B, 9C are preferably driven to rotate at a low speed of, for example, 1 to 20 rpm in order to prevent damage to the granulated sludge. Further, the rotation direction of the second-stage blade 9C is preferably opposite to the rotation direction of the first-stage blade 9B, and thus the rotation directions of the adjacent blades 9B and 9C are opposite to each other. By doing so, the stirring can be performed more effectively.

On the other hand, while the treated water is rising in the separation tank 5, the treated water is separated between the lower first solid-gas liquid separation plate 11A and the second solid-liquid separation plate 11B and the upper first separation liquid. Board 13A and second
Flow through and between the separation plates 13B. in this case,
The granules are formed between the first solid-gas liquid separation plate 11A and the second solid-gas liquid separation plate 11B, and the first separation plate 13A and the second solid-liquid separation plate 11B.
When flowing between and between the separation plate 13B and the separation plate 13B, the granules descend and only the treated water rises to perform solid-gas liquid separation. The descending granules settle in the carrier stationary holding layer 2 due to the settling property. At this time, the first solid-gas separation plate 11A, the second solid-gas separation plate 11B, the first separation plate 1
3A, the granules settled on the upper surface of the second separation plate 13B, the first solid-gas separation plate 11A, the second solid-gas separation plate 11B, the first separation plate 13A, the second separation plate 13B. Since it is inclined, it descends along the first solid-gas liquid separation plate 11A, the second solid-liquid separation plate 11B, the first separation plate 13A, and the second separation plate 13B. Sedimentation into the retaining layer 2 is not hindered.

That is, the outer peripheral portion of the methane fermentation tank 1 is separated into the separation tank 5
By disposing the solid-gas separation plate 11 and the separation plate 13 here, solid-liquid separation is promoted and the sedimentation of granules is further promoted. On the other hand, the treated water from which the granules have been separated flows into the trough-shaped member 12 and is discharged to the outside through the treated water discharge pipe 15.

According to such a methane fermentation tank 1, the reaction tank 4
In the reaction tank 4, the air bubbles attached to or contained in the floating granules are separated by the mechanical stirring means in the reaction tank 4, and the sedimentation property of the granules is recovered. Further, a trough-shaped member 12 is provided above the separation tank 5 so that treated water is discharged, and a solid-gas liquid separation plate 11 and a separation plate 13 are provided in the separation tank 5 provided separately from the reaction tank 4. Etc. are provided to promote the sedimentation of granules and to perform solid-liquid separation of treated water from granules and gas more reliably, so that only treated water is discharged and highly efficient wastewater treatment is performed. be able to.

In particular, since the single methane fermentation tank 1 is used to form both the reaction tank 4 and the separation tank 5,
Space saving can be achieved. In addition, the partition 3 allows the reaction tank 4 and the separation tank 5 to be easily formed inside the tank body 1A, and the upper end of the partition 3 is formed higher than the liquid level in the reaction tank 4, so that the reaction tank 4 Granules are settled stably without being affected by stirring on the separation tank 5.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, a fluid stirring means is provided in the reaction tank 4 instead of the mechanical stirring means. In this embodiment, the fluid-type stirring means is an anaerobic gas (CH ₄ , C) recovered from the reaction tank 4.
It is characterized in that it is configured to include a gas ejection means for compressing O ₂ ) and ejecting it upward from above the carrier stationary holding layer 2 of the reaction tank 4. In this case, the annular pipe 16 is arranged above the annular pipe 6 and a plurality of gas supply holes 16A are opened in the upper part of the peripheral wall of the annular pipe 16. Then, a gas blow-in pipe 18 having a blower 17 interposed is connected in the middle of the gas discharge pipe 8 connected to the top plate 1 a, and the gas blow-in pipe 18 is connected to the annular pipe 16.

In this embodiment, a gas ejection means is provided in the reaction tank 4, and the recovered anaerobic gas is compressed by the blower 17 and ejected by the annular pipe 16 to float in the reaction tank 4. The bubbles attached to or contained in the granules are separated, the settling property of the granules is recovered, and the granules settle in the carrier stationary holding layer 2.

According to this embodiment, since the recovered gas is compressed by the blower 17 and is used for stirring, the anaerobic gas can be effectively used and energy saving can be achieved. The anaerobic gas to be stirred may be a gas introduced from the outside, as long as it is not air. FIG. 4 shows a third embodiment of the present invention.

Also in this embodiment, a fluid type stirring means is provided. As the fluid type stirring means, a configuration is adopted in which the discharged treated water is pressurized and jetted downward from the upper part of the reaction tank 4. In this case, the pipe 19 is arranged above the reaction tank 4, and a plurality of treated water supply holes 19A are formed in the lower portion of the peripheral wall of the pipe 19. On the other hand, a treated water circulation pipe 2 in which a high-pressure pump 21 is interposed in the treated water discharge pipe 15.
0 is connected, and this treated water circulation pipe 20 is connected to the pipe 19.

In this embodiment, the discharged treated water is jetted by the high-pressure pump 21 to hit the floating carrier, so that the bubbles adhering to or contained in the floating carrier are separated, and the sedimentation of the carrier occurs. Will recover. This allows
The granules settle in the carrier stationary holding layer 2, and it becomes difficult for the granules to be discharged together with the treated water, so that the granules are prevented from flowing out. Moreover, the treated water can be effectively used,
It is energy saving. The water to be stirred may be tap water or ground water.

FIG. 5 shows a fourth embodiment of the present invention. In this embodiment, the gas-liquid separation function of the wastewater treatment devices in the first to third embodiments is enhanced. In the following, only the configuration that enhances the gas-liquid separation function will be described. The separation tank 5 has a substantially frustoconical solid shape inclined downwardly toward the outer side in the radial direction of the methane fermentation tank 1 at a distance from its peripheral wall, that is, the outer peripheral surface of the partition wall 3 and the inner peripheral surface of the side plate 1b. A plurality of gas-liquid separating plates 22 are arranged in the vertical direction. Further, the partition wall 3 is provided with an annular gas-liquid separation plate 23 having a substantially mountain-shaped cross section that is inclined downward toward the outside in the radial direction of the methane fermentation tank 1 and is inclined downward toward the inside in the radial direction. A plurality of rows are provided so as to be located above each solid-gas liquid separation plate 22. Gas-liquid separation plate 23
Then, the component member 23A directed outward in the radial direction is formed to be longer than the component member 23B directed inward in the radial direction, and its tip portion slightly overlaps with the inner peripheral end of the solid-gas liquid separation plate 22 as shown in the figure. It is like this. Furthermore, the partition wall 3 includes
An opening 24 is formed in the lower surface of the gas-liquid separation plate 23 for allowing the accumulated air bubbles and the granules having attached or contained air bubbles to reduce the specific gravity to the reaction tank 4.

The opening 24 is formed at a position lower than the upper end of the component member 23B and higher than its lower end. Therefore, the air bubbles and the carrier containing the air bubbles accumulated in the gas-liquid separation plate 23 move to the reaction tank 4, but the treated water does not move to the reaction tank 4. The treated water flowing from the reaction tank 4 into the separation tank 5 contains bubbles and granules that cannot be separated in the reaction tank 4. When such treated water flows upward along the lower side of the solid-gas / liquid separation plate 22, the granules having a high specific gravity settle, and the carrier is left stationary along the upper side of the solid-gas / liquid separation plate 22. Settle in layer 2. Further, bubbles rising along the lower side of the solid-liquid separation plate 22 and granules having a low specific gravity (hereinafter, referred to as bubbles) containing the bubbles are trapped by the gas-liquid separation plate 23 and accumulated on the lower surface thereof. . Gas-liquid separation plate 23
The bubbles and the like accumulated on the lower surface of the tank flow out to the reaction tank 4 through the opening 24 formed in the partition wall 3, while the treated water from which the bubbles and the like have been removed rises in the separation tank 5 to form a gutter-shaped member. It flows into the inside 12 and is discharged to the outside through the treated water discharge pipe 15.

As described above, by installing the solid-gas separation plates 22 and the gas-liquid separation plates 23 alternately and in multiple stages, the bubbles and the like contained in the treated water return to the reaction tank 4, while the granules having a large specific gravity are used. Since the granules return to the carrier stationary holding layer 2, the granules can be effectively prevented from flowing out. FIG. 6 shows a fifth embodiment of the present invention.

In this embodiment, any combination of the first to fourth embodiments, for example, as shown in the figure, the mechanical stirring means in the first embodiment, and the solid-liquid separation plate 22, in the fourth embodiment. Gas-liquid separation plate 24 and opening 24
On the premise of a wastewater treatment apparatus equipped with, the carrier outflow is significantly reduced while improving the ability of the carrier to decompose organic substances.

The lower end of the partition 3 projects into the carrier stationary holding layer 2, while the upper end of the partition 3 is formed higher than the liquid level in the reaction tank 4. A cylinder for guiding the waste water and the carrier introduced from the lower portion of the carrier stationary holding layer 2 to the reaction tank 4 at a predetermined distance from the lower inner peripheral surface of the reaction tank 4, that is, the lower inner peripheral surface of the partition wall 3. The cylindrical portion 25 is provided.

Further, the bottom surface of the carrier stationary holding layer 2 is formed as an inclined surface whose cross-sectional area gradually decreases as it goes downward, specifically, a substantially truncated cone-shaped inclined surface. Further, the upper part of the separation tank 5 is provided with a carrier trap means for trapping bubbles and a carrier having a smaller specific gravity by containing bubbles and letting only the trapped bubbles escape to the upper part of the separation tank 5. Specifically, the carrier trap means includes a circular plate portion 26A having a substantially circular ring shape in which the vertical plate portion 12A of the gutter-shaped member 12 extends below the horizontal plate portion 12B and only the lower side is open, A pipe 26B that allows bubbles introduced from an opening provided in the horizontal plate portion 12B to escape to the upper part of the separation tank 5;
It is configured to include.

According to this structure, the waste water introduced from the lower part of the carrier stationary holding layer 2 is decomposed into methane, carbon dioxide and water by the action of the carrier stationary therein.
At this time, since the cylindrical portion 25 that guides the wastewater and the carrier to the reaction tank 4 is provided, the carrier in which bubbles adhere or are included and lose the sedimentation property is suppressed from being introduced into the separation tank 5. Meanwhile, most of it is introduced into the reaction tank 4. For this reason, the carrier, which has lost its sedimentation property due to the bubbles, is separated into bubbles in the reaction tank 4 and the separation tank 5, respectively, so that it is possible to greatly reduce the possibility that the carriers cannot be separated and flow out to the outside. .

Further, since the bottom surface of the carrier stationary holding layer 2 is formed as an inclined surface whose cross-sectional area gradually decreases as it goes downward, no carrier whose sedimentation property is recovered in the reaction tank 4 or the separation tank 5 is formed. The inclined surface collects the carrier stationary holding layer 2 to a substantially central portion. Therefore, the wastewater is introduced into a region where the carrier density is high, and the anaerobic microorganism can effectively decompose organic substances.

Further, since the carrier trap means is provided on the upper part of the separation tank 5, the carriers and the air bubbles that could not be separated in the reaction tank 4 and the separation tank 5 are the annular portion 26A of the carrier trap means. Trapped by. Then, only the trapped bubbles are guided to the upper portion of the separation tank 5 through the pipe 26B. Therefore, it is possible to prevent the bubbles, even if they cannot be separated, from flowing out to the outside.

Here, if the volume of the separation tank 5 is configured to be larger than the volume of the reaction tank 4, in the separation tank 5,
The ability to separate air bubbles from the carrier is improved. For this reason,
The carrier flowing out from the separation tank 5 to the outside can be significantly reduced. In each of the above-described embodiments, the reaction tank 4 is provided with only one type of mechanical stirring means and fluid type stirring means such as gas and water, but a plurality of types of mechanical stirring means and fluid type stirring means are provided. May be provided, and in short, at least one of mechanical stirring means and fluid stirring means may be provided.

Further, since it is effective that the carrier still standing on the carrier stationary holding layer 2 is activated by stirring and floating after a certain period of time, the carrier standing below the carrier stationary holding layer 2 is activated. It is desirable to separately provide a fluid ejection means for ejecting a fluid (anaerobic gas, treated water) toward the upper side of the stationary holding layer 2. Furthermore, in the present embodiment, an example in which the wastewater treatment device according to the present invention is applied to a methane fermentation tank has been described, but other wastewater that decomposes organic matter in wastewater into anaerobic gas by the action of anaerobic microorganisms. It may be applied to a processing device.

[0052]

As described above, according to the first aspect of the invention, the wastewater treatment device is divided into the reaction tank and the sedimentation tank, and the stirring means is provided in the reaction tank, so that the floating carrier can be used. The air bubbles that adhere or are included in the carrier are separated, and the settling property of the carrier is recovered. Therefore, the carrier quickly settles in the carrier stationary holding layer, and the carrier is less likely to be discharged together with the treated water. Moreover, since the waste water and the carrier are positively stirred and mixed, the reaction speed is increased, and an efficient treatment effect can be obtained.

According to the second aspect of the present invention, the effect of stirring in the reaction tank does not affect the separation tank, and a stable stirring action is performed. According to the third aspect of the invention, the carrier, which loses the sedimentation property due to the bubbles, is separated into the reaction tank and the separation tank, respectively. It can be reduced.

According to the fourth aspect of the present invention, the air bubbles adhering to or contained in the floating carrier are effectively separated by the mechanical stirring means or the fluid stirring means, and the sedimentability of the carrier is surely restored. Moreover, the carrier can be effectively prevented from flowing out.
Moreover, since the waste water and the carrier are positively stirred and mixed, the reaction speed is increased, and an efficient treatment effect can be obtained.

According to the fifth aspect of the invention, the carrier floating on the liquid surface is hit by the jetting fluid to separate air bubbles,
The sedimentability of the carrier can be restored. Further, the methane and carbon dioxide generated in the reaction tank can be effectively used. According to the sixth aspect of the invention, the carrier floating on the liquid surface is hit by the jetted fluid to separate the bubbles, so that the settling property of the carrier can be recovered. In addition, it is possible to effectively use the waste water recovered from the separation tank after the decomposition treatment.

According to the seventh aspect of the invention, the solid-gas liquid separation plate provided in the separation tank can more reliably perform solid-liquid separation of the treated water, the carrier and the gas. Claim 8
According to the described invention, the labyrinth passage formed in the separation tank can more reliably perform solid-liquid separation between the treated water and the carrier. According to the invention of claim 9, the bubbles contained in the treated water and the carrier containing the bubbles and having a reduced specific gravity are returned to the reaction tank after being trapped by the gas-liquid separation plate, so that the outflow of the carrier is prevented. It can be effectively prevented.

According to the tenth aspect of the present invention, the air bubbles and the carrier having a low specific gravity containing bubbles are trapped, and the trapped bubbles and the carrier having a low specific gravity including the bubbles are returned to the reaction tank. The liquid separation plate can be easily constructed. According to the eleventh aspect of the invention, the wastewater is introduced into the region where the carrier density is high, so that the anaerobic microorganisms can effectively decompose organic substances.

According to the twelfth aspect of the present invention, it is possible to prevent the bubbles, even if they cannot be separated, from flowing out to the outside. According to the thirteenth aspect of the present invention, the fluid ejecting means is activated every certain period of time to eject the fluid upward from the lower portion of the carrier stationary holding layer, so that the carrier stationary holding layer is allowed to stand still. The existing carrier can be stirred and floated to give the activity.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a methane fermentation tank showing a first embodiment of the present invention.

[Fig. 2] Side view of the lower part of the separation tank of the methane fermentation tank of the same as above.

FIG. 3 is a vertical sectional view of a methane fermentation tank showing a second embodiment of the present invention.

FIG. 4 is a vertical sectional view of a methane fermentation tank showing a third embodiment of the present invention.

FIG. 5 is an enlarged vertical sectional view of a methane fermentation tank showing a fourth embodiment of the present invention.

FIG. 6 is a vertical sectional view of a methane fermentation tank showing a fifth embodiment of the present invention.

[Explanation of symbols]

1 methane fermentation tank 2 Carrier stationary holding layer 3 partitions 4 reaction tanks 5 separation tanks 6 annular pipe 7 Raw water supply pipe 8 gas exhaust pipe 9 stirring blades 10 motors 11 Solid-gas separation plate 12 Gutter-shaped member 13 Separation plate 15 Treated water discharge pipe 22 Solid-liquid separation plate 23 Gas-liquid separation plate 25 tube 26A annular part 26B pipe

Claims (13)

[Claims] 1. A wastewater treatment apparatus for decomposing organic matter in wastewater into methane, carbon dioxide, and water by the action of anaerobic microorganisms, wherein the minimum required amount of a carrier self-granulated by the anaerobic microorganisms is allowed to stand. And a stirring means for separating air bubbles adhering to or contained in a floating carrier, which is located above the carrier stationary holding layer and which is decomposed by the anaerobic microorganism. And a lower part of the reaction tank which communicates with the reaction tank for discharging the waste water, and the waste water after the decomposition treatment introduced from the lower portion of the reaction tank and the carrier are caused to flow upward, and the waste water after the decomposition processing is discharged from the upper portion. A wastewater treatment apparatus comprising: a separation tank for allowing the carrier to settle to a lower portion to separate the wastewater after decomposition treatment from the carrier. 2. A partition is provided between the reaction tank and the separation tank,
2. The wastewater treatment system according to claim 1, wherein the lower end of the partition wall has a gap with the upper surface of the carrier stationary holding layer, and the upper end of the partition wall is formed higher than the liquid level in the reaction tank. apparatus. 3. A partition is provided between the reaction tank and the separation tank,
The lower end of the partition wall protrudes into the carrier stationary holding layer, while the upper end of the partition wall is formed higher than the liquid level in the reaction tank, and is spaced a predetermined distance from the lower inner peripheral surface of the reaction tank. 2. The waste water treatment apparatus according to claim 1, further comprising a tubular portion that separates the waste water introduced from the lower portion of the carrier stationary holding layer to the reaction tank through the carrier stationary holding layer. . 4. The reaction tank comprises at least one of a mechanical stirring means for stirring by an object and a fluid stirring means for stirring by jetting a fluid into the reaction tank. The wastewater treatment apparatus according to any one of claims 1 to 3. 5. The fluid agitation means includes gas ejection means for compressing methane and carbon dioxide recovered from the reaction tank and ejecting the compressed methane and carbon dioxide upward from an upper portion of a carrier stationary holding layer of the reaction tank. The wastewater treatment device according to claim 4, which is configured. 6. The fluid-type agitation means includes a liquid ejection means for pressurizing the waste water after the decomposition treatment recovered from the separation tank and ejecting it downward from the upper part of the liquid surface of the reaction tank. The wastewater treatment device according to claim 4, wherein 7. The separation tank is provided with an inclined solid-gas separation plate for separating a solid-gas liquid consisting of a carrier, a gas consisting of methane and carbon dioxide, and waste water after decomposition treatment. The wastewater treatment apparatus according to any one of claims 1 to 6. 8. The labyrinth passage is formed in the separation tank by a plurality of inclined separation plates having closed upper parts in order to separate the waste water after the decomposition treatment and the carrier. ~ The wastewater treatment device according to claim 7. 9. The separation tank is provided with an inclined solid-gas liquid separation plate spaced apart from the peripheral wall thereof, and is located above the solid-gas liquid separation plate, and contains bubbles and bubbles to reduce the specific gravity. 7. A gas-liquid separating plate for trapping the carrier, and returning the trapped air bubble and the carrier containing the air bubble and having a reduced specific gravity to the reaction tank, are provided. The wastewater treatment device according to one. 10. The gas-liquid separation plate comprises a first inclined plate inclined downward from the partition between the reaction tank and the separation tank toward the outer wall toward the separation tank, and from the partition to the reaction tank side. A second inclined plate that inclines downward toward the center, and the lower end of the first inclined plate is lower than the lower end of the second inclined plate. The wastewater treatment device according to claim 9, wherein the opening is provided at a position lower than the upper end of the inclined plate 2 and lower than the lower end thereof. 11. The bottom surface of the carrier stationary holding layer is formed as an inclined surface whose cross-sectional area gradually decreases as it goes downward. The wastewater treatment device described in. 12. An upper part of the separation tank is provided with a carrier trap means for trapping bubbles and a carrier having a low specific gravity by containing bubbles and releasing only the trapped bubbles to the upper part of the separation tank. Claims 1 to 11
The wastewater treatment device according to any one of 1. 13. The fluid jetting means for jetting a fluid upward from the lower part of the carrier stationary holding layer is provided in the lower part of the carrier stationary holding layer. Item 13. The wastewater treatment device according to any one of items 12.