JP3692893B2 - Aerobic treatment tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aerobic treatment tank, and more particularly to an aerobic treatment tank in which water to be treated and a granular carrier are brought into contact in a fluid state.
[0002]
[Prior art]
FIG. 11 shows an example of an aerobic treatment tank according to a conventional technique. A carrier 12 holding microorganisms is placed in the tank 10. In addition, a partition wall 14 that divides the inside of the tank into two areas in a planar manner is disposed at the center of the tank 10. The upper part and the lower part of the partition wall 14 are missing, and the upper and lower sides communicate with one area 16 and the other area 18. An air diffuser 20 that blows out aeration air upward is installed at the middle position of the area 16.
[0003]
The water to be treated is supplied into the tank 10 from the inflow pipe 22, and the water to be treated is filled with maintaining a constant water level. When the air is blown out from the air diffuser 20 in this state, an upward flow is generated in the water to be treated by the lift action of the blown air, and the water to be treated is circulated clockwise between the areas 16 and 18. A stream X is formed. The carrier 12 also circulates while flowing in the tank 10 on the circulating flow X of the water to be treated.
[0004]
In the process of circulating for a predetermined time while the water to be treated and the carrier 12 are in contact with each other in a fluid state, the water to be treated is purified by the action of the microorganisms held on the carrier 12 under aerobic conditions by the aeration. The treated water passes through the screen 24 for preventing the carrier 12 from flowing out and is discharged out of the tank through the outflow pipe 26.
[0005]
In the aerobic treatment tank, it is important for improving the treatment efficiency that a carrier having a specific gravity as close as possible to the water to be treated is introduced at an appropriate concentration and circulated while being uniformly mixed and contacted with the water to be treated. Since the density of the water to be treated varies depending on the temperature, it is difficult to make the specific gravity of the carrier coincide with that of the water to be treated. For this reason, when a high molecular weight material is used as a raw material for the carrier, a carrier having a specific gravity of about 1.01 to 1.08 is preferably used from the viewpoints of handleability, manufacturing restrictions, cost, and the like. .
[0006]
[Problems to be solved by the invention]
However, it has been found that in this type of aerobic treatment tank, a considerably high level of technology is required to circulate the carrier while being in uniform mixed contact with the water to be treated. That is, according to the inventor's experience, when a carrier having a specific gravity of about 1.01 to 1.08 is used, a phenomenon in which the carrier 12 settles and accumulates at the bottom of the right end of the area 18 as shown in FIG. It was. Such a sedimentation phenomenon of the carrier increases the proportion of the carrier that does not contribute to the reaction, lowers the contact efficiency between the carrier and the water to be treated, and causes the treatment performance to deteriorate. In addition, microorganisms adhering to the sedimented carrier may rot under anaerobic conditions, or the carriers may adhere to each other and cause adverse effects. Furthermore, when the specific gravity of the carrier is about 2.0, such as activated carbon, the sedimentation phenomenon of the carrier becomes even more prominent, and there is a concern that the processing performance may be lowered and trouble in operation may be caused.
[0007]
An object of the present invention is to provide an aerobic treatment tank that improves the above-mentioned problems of the prior art, makes it difficult for the carrier to settle and deposit on the bottom of the tank, and can improve the contact efficiency between the carrier and the water to be treated. It is in.
[0008]
[Means for Solving the Problems]
The present invention relates to an aerobic treatment tank in which water to be treated and a granular carrier having a specific gravity larger than that of the water to be treated are brought into contact with each other in a fluidized state, and a diffuser that blows out air into one area divided in a plane. An apparatus is disposed, and the treated water and the carrier are circulated between the one area and the other area by the lift action of the blown air, and the treated water and the carrier are circulated in the other area. with arranging a screen for separating, said the other area is provided a guide member to separate the circulation flow X ₁ of the outer loop along the screen surface in the circulation flow and the circulation flow X ₀ of the inward turning, the circulation flow the X ₁ along the side wall of the vessel, characterized in that to guide the tank bottom.
[0009]
The ratio of the inlet opening area and the outlet opening area of the circulation path of the circulating flow X ₁ is desirably 1 to 5.
[0011]
In the present invention, it is desirable that a partition wall for partitioning the one area and the other area is disposed in the processing tank.
[0012]
Further, the present invention is characterized in that by a deformable lower end of the guide member, the outlet opening area of the circulation path of the circulating flow X ₁ is adjustable.
[0013]
In the present invention, the air diffuser arranged in the one area is divided into an outer side and an inner side, and the lift action of the air diffused from the outer air diffuser is adjusted to be larger than that of the inner side. It is desirable that
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. In the drawings shown below, components having the same reference numerals as those in FIG. 11 described above are elements having the same or similar functions as those shown in FIG. 11, and description thereof may be omitted.
[0015]
FIG. 1 is a cross-sectional view showing a first embodiment of the present invention, and FIG. 2 is a view taken along the line DD in FIG. In this embodiment, a guide plate 30 is provided in the other area 18. The guide plate 30 has a predetermined interval with respect to the screen 24 surface and is provided substantially parallel to the screen 24 surface. The lower end of the guide plate 30 extends to a position close to the side wall 28.
[0016]
In the above configuration, the circulating flow X from the area 16 is divided into the circulating flow X ₀ and the circulating flow X ₁ at the upper end position of the guide plate 30 by the presence of the guide plate 30 in the other area 18. The circulating flow X ₀ returns to one area 16 from below the partition wall 14 as an inward flow passing between the partition wall 14 and the guide plate 30.
[0017]
On the other hand, circulation X ₁ is partitioned by the guide plate 30, flows downward guide plate 30 and the screen 24 side, the circulation path 32 formed between the side walls 28 along the side wall 28, circulating flow X ₂ To the tank bottom 34. The ratio of the inlet opening area A ₁ and the outlet opening area A ₂ of the circulation path 32 is set to a range of 1 to 5, preferably 1.5 to 3. That is, by making the outlet opening area A _{2 the} same or smaller than the inlet opening area A ₁ , the flow rate of the circulating flow X ₂ becomes relatively large, and the water to be treated and the carrier 12 are moved along the tank bottom 34. And flush out strongly. For this reason, it is possible to prevent the carrier 12 from being deposited on the tank bottom 34.
[0018]
If the ratio of the inlet opening area A ₁ and the outlet opening area A ₂ of the circulation path 32 is less than 1, the flow rate of the circulating flow X ₂ cannot be increased, and the carrier 14 is deposited and deposited on the tank bottom 34. It becomes easy. Further, when the ratio exceeds 5, the flow rate ratio of the circulation flow X ₂ to the circulation flow X ₁ can be increased, but the water flow resistance at the outlet opening of the circulation path 32 increases and the circulation flow rate in the circulation path 32 decreases. To do.
[0019]
As described above, according to the first embodiment, the guide plate 30 that guides the water to be treated and the carrier 12 to the tank bottom 34 along the side wall 28 of the tank is provided in the other area 18. And the carrier 12 can be strongly flowed out along the tank bottom 34, and the carrier 12 can be prevented from being deposited on the tank bottom 34. Further, since the ratio of the inlet opening area A ₁ and the outlet opening area A ₂ of the circulation path 32 is set in the range of 1 to 5, preferably in the range of 1.5 to ₃ , the flow rate of the circulating flow X ₂ is set to the tank. The carrier 12 can be of an appropriate size that does not settle and deposit on the bottom 34. Further, since the guide plate 30 has a predetermined interval with respect to the screen 24 surface and is provided substantially parallel to the screen 24 surface, the circulating flow X ₁ forms a stable flow along the screen 24 surface, and the carrier 12 can be expected to clean the screen 24 surface. Further, since the partition wall 14 for partitioning the one area 16 and the other area 18 is provided in the processing tank, the flow for short-circuiting each other area can be reduced, and a dynamic and stable circulation flow is formed as the entire tank. it can.
[0020]
FIG. 3 is a sectional view showing a second embodiment of the present invention. In this embodiment, a guide member 36 having a polygonal cross section for guiding the water to be treated and the carrier 12 to the tank bottom 34 along the side wall 28 of the tank is provided. The circulating flow from one area is divided into the circulating flow X ₀ and the circulating flow X ₁ at the upper end position of the guide member 36 in the other area 18. The circulation flow X ₁ flows in the circulation path 32 along the surface of the screen 24 and the side wall 28 of the tank, and at the lower part, the circulation flow X _{2 at a high} speed maintains the narrow outlet opening area A ₂ and the side flow 28 and the corner inclined portion 38. , And flows in the order of the tank bottom 34.
[0021]
According to the second embodiment, since the water to be treated and the carrier 12 are reliably guided to the tank bottom 34 by the circulation flow X ₂ at a high speed, the carrier 12 settles on the tank bottom 34. Accumulation can be prevented more reliably.
[0022]
FIG. 4 is a sectional view showing a third embodiment of the present invention. In the present embodiment, guide plates 40 and 42 which are guide members are provided in two separate upper and lower stages. The circulating flow from one area is separated into a circulating flow X ₀ , a circulating flow X ₁ , and a circulating flow X ₃ in the upper part of the other area 18, and after the circulating flow X ₁ and the circulating flow X ₃ are merged in the circulation path 32. Then, it becomes a circulation flow X ₂ and flows toward the tank bottom 34. Also in this embodiment, since the outlet opening area A ₂ is narrowed, the circulating flow X _{2 at a high} speed can be obtained, and the carrier 12 can be prevented from being settled and deposited on the tank bottom 34.
[0023]
According to the third embodiment, the treated water passes through the screen 24 while the circulating flow X ₁ flows through the circulating path 32, so the flow rate of the circulating flow X ₁ decreases accordingly. This decrease amount is supplemented by the circulation flow X ₃ , and the flow velocity of the circulation flow X ₂ can be stably maintained.
[0024]
FIG. 5 is a cross-sectional view showing a fourth embodiment of the present invention. In the present embodiment, the upper portion of the guide plate 44 extends to one area 16, and its end 46 is provided downward at a position that bisects the air diffuser 20. For this reason, the upward flow from the a zone of the air diffuser 20 passes through the outside of the guide plate 44 as it is as the circulating flow X _1, and the upward flow from the b zone becomes the circulating flow X ₀ as it is. You will pass inside. Also in this embodiment, the outlet opening area A ₂ is narrowed and the flow rate of the circulating flow X ₁ is reliably ensured, so that a fast circulating flow X ₂ can be reliably obtained, It is possible to reliably prevent the carrier 12 from being deposited on the tank bottom 34.
[0025]
In FIG. 5, the boundary between one area 16 and the other area 18 is not obvious. Therefore, in the present embodiment, the inside of the tank 10 is divided by the virtual line Y, the side on which the air diffuser 20 on the left side of the virtual line Y is disposed is set as one area 16, and the guide plate on the right side of the virtual line Y It is assumed that the side on which the main part 44 is arranged is understood as the other area 18, and the position of the virtual line Y can be understood by moving right and left as appropriate. 3 and 4 described above and FIG. 7 described later can assume a boundary between one area 16 and the other area 18 in the same way as described above.
[0026]
FIG. 6 is a cross-sectional view showing a fifth embodiment of the present invention. In the present embodiment, the lower portion of the guide plate 48 hangs down in parallel with the side wall 28, and the lower end thereof forms an outlet opening of the circulation path 32 with the tank bottom portion 34. Also in this embodiment, since the outlet opening area A ₂ is narrowed, a high-speed circulation flow X ₂ can be obtained with certainty, and the carrier 12 can be prevented from being deposited on the tank bottom 34.
[0027]
FIG. 7 is a cross-sectional view showing a sixth embodiment of the present invention. In this embodiment, the screen 24 is provided on the one area 16 side, the water to be treated is supplied from the inflow pipe 22 provided on the other area 18 side, and the treated water is discharged on the one area 16 side. It is discharged from the tube 26. The lower portion of the guide plate 50 is inclined so that the distance from the side wall 28 is gradually reduced, and the lower end thereof forms an outlet opening of the circulation path 32 with the corner inclined portion 38. Also in this embodiment, since the outlet opening area A ₂ is narrowed, the circulating flow X _{2 at a high} speed can be obtained, and the carrier 12 can be prevented from being settled and deposited on the tank bottom 34.
[0028]
FIG. 8 is a cross-sectional view showing a seventh embodiment of the present invention. In this embodiment, it is configured symmetrically with respect to the center line Z. The portion on the right side from the center line Z has substantially the same structure as that of the first embodiment shown in FIG. 1, and the carrier is settled and deposited on the bottom of the tank by forming a circulating flow similar to the case of the first embodiment. To prevent. Further, the left part from the center line Z also forms a target circulation flow with the right part to prevent sedimentation and deposition of the carrier on the bottom of the tank. This embodiment is suitable for a large tank having a large flow rate for water to be treated.
[0029]
FIG. 9 is an explanatory view of a main part of a guide member showing an eighth embodiment of the present invention.
In FIG. 9A, the lower end 52A of the guide member 52 is rotatable in the direction of the arrow through a hinge 54. For this reason, the outlet opening area A ₂ of the circulation path 32 can be adjusted to the most preferable value by rotating and fixing the lower end 52A at a necessary time. In the case of FIG. 9B, the lower end 56A of the guide member 56 is slidable in the direction of the arrow. For this reason, the outlet opening area A ₂ of the circulation path 32 can be adjusted to the most preferable value by sliding and fixing the lower end 56A at a necessary time.
[0030]
FIG. 10 is a cross-sectional view showing a ninth embodiment of the present invention. In this embodiment, the air diffuser 20 is separated into a first air diffuser 58 and a second air diffuser 60. The first air diffuser 58 is disposed on the outside (close to the side wall) of the tank 10, and the upward flow from the first air diffuser 58 mainly forms an external circulation flow via the circulation path 32. Further, the second air diffuser 60 is disposed on the inner side (near the center) of the tank 10, and the upward flow from the second air diffuser 60 mainly forms an inward circulation flow that does not pass through the circulation path 32. .
[0031]
In the present embodiment, the opening degree of the flow rate adjusting valves 62 and 64 for each air diffuser is adjusted, a large amount of air is sent to the first air diffuser 58, and air is diffused from the first air diffuser 58. The lift action of air is made larger than that of the second air diffuser 60. By adjusting in this way, the flow rate of the circulating flow X ₁ is surely ensured, and the circulating flow X _{2 at a high} speed is surely obtained, and the carrier is prevented from sedimentation and accumulation at the bottom of the tank. Can do.
[0032]
【The invention's effect】
As described above, according to the aerobic treatment tank according to the present invention, it is possible to prevent the carrier from being deposited on the bottom of the tank. For this reason, the contact efficiency of a support | carrier and to-be-processed water can be improved.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a first embodiment of the present invention. FIG. 2 is a sectional view taken along the line DD in FIG. 1. FIG. 3 is a sectional view showing a second embodiment of the invention. FIG. 5 is a cross-sectional view showing a fourth embodiment of the present invention. FIG. 6 is a cross-sectional view showing a fifth embodiment of the present invention. FIG. 8 is a cross-sectional view showing a seventh embodiment of the present invention. FIG. 9 is an explanatory view of a main part of a guide member showing an eighth embodiment of the present invention. Sectional view showing a ninth embodiment of the present invention. FIG. 11 is a sectional view showing an example of an aerobic treatment tank according to the prior art.
DESCRIPTION OF SYMBOLS 10 ... Tank 12 ... Carrier 14 ... Bulkhead 16 ... One area 18 ... The other ELER 20 ... Air diffuser 24 ... Screen 28 ... Side wall 30 ... Guide plate 32 ... Circulation path 34 ... ... tank bottom 36 ... guide member 38 ... corner inclined part 58 ... first air diffuser 60 ... second air diffuser

Claims (2)

In an aerobic treatment tank in which the water to be treated and a granular carrier having a specific gravity greater than that of the water to be treated are brought into contact in a fluid state, an air diffuser that blows out air is arranged in one area that is divided in a plane. In order to circulate the treated water and the carrier between the one area and the other area by the lift action of the blown air, and to separate the treated water and the carrier in the other area bath with said the other area is provided a guide member to separate the circulation flow X ₁ of the outer loop along the screen surface in the circulation flow and the circulation flow X ₀ of the inward turning, the circulation flow X ₁ to dispose the screen An aerobic treatment tank characterized by being guided to the bottom of the tank along the side wall. The aerobic treatment tank according to claim 1, wherein an outlet opening area of the circulation path of the circulation flow X ₁ is adjustable by making the lower end of the guide member deformable.

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