JP2018164894A - Arrangement method of water treatment system and diffuser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water treatment system equipped with a diffuser capable of generating a strong swirling flow in a tank to enhance air lift effect.SOLUTION: There is provided a water treatment system equipped with a diffusion tank and a diffuser arranged adjacent to one side wall of the diffusion tank while forming a gap with the other side wall of the diffusion tank, wherein the diffuser gradually decreases or increases the amount of diffusion as extending from the other side wall of the diffusion tank toward the one side wall thereof. This water treatment system can prevent scum deposition on a water surface by generating a strong swirling flow on the water surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a water treatment system including an air diffuser for dispersing fine bubbles in a liquid and a method for arranging the air diffuser. More specifically, the present invention relates to a water treatment system including an air diffuser used for an air diffuser for treating wastewater and the like, and an arrangement method of the air diffuser.

  As a method of treating wastewater such as sewage and sewage, an air diffuser is installed in the wastewater treatment device, and an air diffuser is installed in the air diffuser, and this diffuser disperses air into the wastewater as fine bubbles. There is a way to do it. The air diffuser converts oxygen or the like supplied by the blower into fine bubbles and supplies the air into the air diffusion tank to increase the amount of dissolved oxygen in the water to be treated. In particular, a diffuser for improving the oxygen transfer efficiency related to the processing efficiency is widely used.

For example, Patent Document 1 describes a water treatment system provided with a membrane-type air diffuser as an air diffuser.
In Patent Document 1, in air diffusion using a membrane air diffuser, the air flow rate to the membrane air diffuser is set to a predetermined value or less, thereby reducing the bubble diameter and narrowing the bubble diameter distribution width. Therefore, it is described that high oxygen transfer efficiency is achieved and water treatment efficiency is increased.

JP 2008-221158 A

  In the ultrafine bubble diffuser such as the membrane diffuser described in Patent Document 1, the oxygen transfer efficiency can be increased by reducing the bubble diameter. However, since the air lift effect due to the bubbles is reduced, it is difficult to generate a strong swirling flow in the tank. As a result, the flow velocity at the water surface is lowered, and there arises a problem that the scum tends to stay on the water surface.

  Then, the subject of this invention is providing the water treatment system provided with the diffuser which can raise the air lift effect and can generate a strong swirl flow in a tank.

As a result of earnestly examining the above problems, the present inventor seems to locally increase the aeration density in the water treatment system including the aeration apparatus that places the aeration apparatus close to one side wall of the aeration tank. In addition, the present inventors have found that by reducing or increasing the amount of air diffused by the air diffuser, a strong flow occurs on the water surface, and scum accumulation can be prevented on the water surface.
Specifically, this invention is the arrangement | positioning method of the following water treatment systems and aeration apparatuses.

  The present invention for solving the above-mentioned problems is an air diffuser installed near a diffuser tank and one side wall of the diffuser tank with a gap formed between the other side wall of the diffuser tank. A water treatment system including an apparatus, wherein the air diffuser is configured such that the amount of air diffused gradually decreases or increases from the other side wall toward the one side wall.

  According to the water treatment system of the present invention, the air diffuser is configured so that the amount of air diffused gradually decreases or increases from the other side wall of the air diffusion tank toward the one side wall. A region having a high air lift effect is generated, and a strong swirling flow is generated in the air diffusion tank. As a result, the flow velocity on the water surface increases, and the effect of preventing scum accumulation on the water surface is achieved.

Furthermore, as one form of a water treatment system provided with the air diffusing device of the present invention, the air diffusing device gradually increases the amount of air diffusing as it goes from the other side wall to the one side wall. It is.
According to this feature, the density of the air diffuser closer to the side wall of the air diffusion tank is increased, so that a strong upward flow is generated in the vicinity of one side wall close to the air diffuser. This upward flow becomes a flow toward the other side wall on the water surface, and becomes a downward flow near the other side wall. That is, a swirl flow that swirls the entire diffusion tank is formed. This swirl flow can prevent scum accumulation on the water surface more reliably, since the flow velocity on the water surface is remarkably increased compared to the air diffuser arranged so that the amount of air diffused becomes uniform.

Furthermore, as one form of a water treatment system provided with the air diffusing device of the present invention, the air diffusing device is composed of a plurality of air diffusing gas, and the air diffusing gas is arranged so as to be closely packed toward the one side wall. It is characterized by that.
According to this feature, in a state where the amount of air supplied to the air diffuser is constant, the air diffuser density closer to the side wall of the air diffuser can be increased, and a strong flow on the water surface can be generated.

  Moreover, this invention for solving the said subject is a method of arrange | positioning the diffuser which consists of a several diffused gas to a diffuser tank, Comprising: The said diffuser is provided in one side wall of the said diffuser tank. Proximity is installed with a gap between the other side wall of the air diffuser and the air diffused gas is arranged so as to be densely packed toward the one side wall. It is.

  According to the arrangement method of the aeration apparatus of the present invention, the above-described water treatment system can be simply constructed, and the flow velocity of the water surface in the aeration tank can be increased.

  According to the water treatment system provided with the air diffusing device of the present invention, it is possible to provide a water treatment system provided with an air diffusing device that can enhance the air lift effect and can generate a strong swirling flow in the tank.

It is a schematic explanatory drawing which shows the structure of the water treatment system of the 1st Embodiment of this invention. (A) It is a schematic perspective view of the water treatment system of the 1st Embodiment of this invention. (B) It is a top view of the water treatment system of the 1st embodiment of the present invention. (C) It is a side view of the water treatment system of the 1st embodiment of the present invention. (I-I arrow view in FIG. 1b) It is a schematic explanatory drawing which shows the structure of the water treatment system of the 2nd Embodiment of this invention. (A) It is a top view of the water treatment system of the 2nd Embodiment of this invention. (B) It is a side view of the water treatment system of the 2nd Embodiment of this invention. (II-II arrow view in FIG. 2a) It is the figure which showed the result of the water surface flow velocity simulation. (A) It is the figure which showed the result in the water treatment system of the 1st Embodiment of this invention. (B) It is the figure which showed the result in the water treatment system provided with the conventional turning-type aeration apparatus which arranged the aeration gas at equal intervals. It is the graph which compared the water surface average flow velocity in the water treatment system of the water treatment system of the 1st Embodiment of this invention, and the water treatment system provided with the conventional swirl type diffuser which arrange | positioned the diffused gas at equal intervals.

  The water treatment system of the present invention is used for a waste water treatment apparatus having an air diffuser for dispersing fine bubbles in a liquid. Particularly preferably, it is used in a water treatment system provided with an ultrafine bubble diffuser used in an aeration tank for biologically treating wastewater or the like with activated sludge.

  A water treatment system including an air diffuser according to the present invention is installed in a space between an air diffuser and one side wall of the air diffuser and between the other side wall of the air diffuser. A water treatment system including an air diffuser, wherein the air diffuser gradually decreases or increases as it goes from the other side wall to the one side wall.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the attached screen. Note that this embodiment does not limit the present invention.

[First Embodiment]
FIG. 1 is a schematic explanatory diagram illustrating a configuration of a water treatment system including an air diffuser according to a first embodiment of the present invention. (A) It is a whole schematic perspective view of the water treatment system of the 1st Embodiment of this invention. (B) It is a top view of the water treatment system of the 1st embodiment of the present invention. (C) It is a side view of the water treatment system of the 1st embodiment of the present invention. (I-I arrow view in FIG. 1b)
As shown in FIG. 1, in the water treatment system 10 of the present embodiment, an air diffuser 1a is installed in an air diffuser 2 of a water treatment facility using activated sludge, for example, and the air diffuser 1a is an air diffuser 2 It has a diffuser unit 4 composed of a plurality of diffused gases 3 connected to the blower B, and is immersed in the treated water W (mixed liquid of treated water and activated sludge). When air is supplied from the blower B, air bubbles are generated in the treated water W from the air diffusion unit 4 to perform air diffusion.

(Aeration tank)
The air diffuser 2 has an upper hunch Hu and a lower haunch Hs in a substantially rectangular parallelepiped tub having side walls 2a and 2b, and a blower B for supplying air containing oxygen to the diffuser 1a outside. ing.
An air diffuser 1 a is provided inside the air diffuser 2 so as to be substantially parallel to the bottom of the air diffuser 2. The position of the air diffuser 1 a in the depth direction of the air diffuser 2 is not particularly limited, but is usually installed near the bottom of the air diffuser 2. In consideration of the restriction on the discharge pressure of the blower B and the balance with existing facilities, the air diffuser 1a may be installed at a relatively high position.

(Air diffuser)
The air diffuser 1a includes an air diffuser unit 4 composed of an air diffuser 3 arranged in parallel in the width direction of the air diffuser 2 (the vertical direction in FIG. 1b; hereinafter simply referred to as “width direction”). It is what has. A plurality of aeration units 4 are arranged in parallel along the length direction of the aeration tank 2 (left-right direction in FIG. 1b; hereinafter, simply referred to as “length direction”).

  The entire air diffuser 1a is disposed close to one side wall 2a of the air diffusion tank, and a gap G is formed between the other side wall 2b. Therefore, the bubbles generated from the air diffuser 1a generate an upward flow in the region of the air diffusion tank 1a, the upward flow flows toward the other side wall 2b, and forms a downward flow in the region of the gap G.

The region in which the air diffuser 1a is disposed (the region from one side wall 2a to the outermost end on the gap G side of the air diffuser unit 4) is preferably 70% or less in the width direction of the air diffuser 2. By providing the diffuser 1a in this range, a sufficient downward flow is generated in the region of the gap G, and a swirl flow that circulates the entire diffuser tank 2 is formed.
Moreover, it is preferable that the area | region which arrange | positions the diffuser 1a is 50% or more of the width direction of the diffuser tank 2. By providing the air diffuser 1a, the balance between the upward flow generated from the region where the air diffuser 1a is arranged and the downward flow generated in the region of the gap G is good, and a good swirl flow is present in the entire diffuser tank 2. It is formed.

(Aeration unit)
The diffuser unit 4 is a plurality of diffused gases 3 arranged in the width direction of the diffuser tank 2 and an air supply pipe that extends in the width direction on the diffused gas 3 and communicates the inside of the diffused gas 3 in an airtight manner. And a certain header pipe 6. The air from the blower B is supplied to the header pipe 6 through the air supply pipe 7.

  As shown in FIGS. 1a and 1b, the air diffusion unit 4 is disposed so as to be close to one side wall 2a of the air diffusion tank 2 and to form a gap G between the other side wall 2b of the air diffusion tank. Has been. Moreover, it arrange | positions so that the installation space | interval of the diffused gas 3 may become dense as it goes to one side wall 2a. A plurality of the air diffusion units 4 are arranged in parallel along the length direction of the air diffusion tank 2.

  According to such a configuration of the air diffusion unit 4, as shown in FIG. 1c, the air diffusion density from the side of the air diffusion tank side wall 2a where the air diffusion 3 is densely provided becomes high. Therefore, a stronger upward flow is generated in the vicinity of the air diffusion tank side wall 2a, and this upward flow reaches the water surface. After the scum S on the water surface is pushed toward the air diffusion tank side wall 2b, it becomes a downward flow and becomes a gap G. Pass through. And a downward flow flows through the bottom part of the air diffusion tank 2, goes to the air diffusion tank side wall 2a from the air diffusion tank side wall 2b side, and a swirl flow will arise in the air diffusion tank 2 whole.

  The swirling flow formed in this way can prevent scum accumulation on the water surface more reliably because the flow velocity on the water surface is dramatically increased compared to the air diffuser arranged so that the amount of air diffused is uniform. can do.

  In addition, it does not restrict | limit especially as a means for adjusting a diffused density, The means which arrange | positions the diffused gas 3 densely by adjusting the installation space | interval of the diffused gas 3 like 1st Embodiment. In addition, for example, means for adjusting the amount of air supplied to the air diffuser, means for adjusting the number or size of the air diffuser holes and slits formed in the air diffuser, and the like may be used. Means for arranging the air diffused densely and the air diffuser port formed in the air diffused in that the air diffuse density can be adjusted while forming fine bubbles having a uniform diameter throughout the air diffuser. Means for adjusting the number are preferred.

  Further, the amount of air diffusion may gradually decrease from the side of the air diffusion tank side wall 2b toward the air diffusion tank side wall 2a. Thereby, since the diffuse density in the diffused gas 3 by the side of the diffuser tank side wall 2b increases, the flow velocity on the water surface can be increased. From the viewpoint of forming a favorable swirling flow in the entire air diffusion tank 2, the amount of air diffusion gradually increases from the air diffusion tank side wall 2b side toward the air diffusion tank side wall 2a as in the first embodiment. It is preferable.

  As a configuration for gradually decreasing or increasing the amount of air diffused, even if the configuration in which the amount of air diffused continuously decreases or increases from the side of the air diffuser tank side wall 2b to the side of the air diffuser tank side wall 2a, the air diffuser is intermittently diffused. A configuration may be adopted in which the amount decreases or increases.

(Spread gas)
The air diffuser 3 of the present invention is an air diffuser tube made of a tubular member around which a membrane having fine air diffuser holes passing through air is wound, and is also referred to as a “membrane pipe ultrafine bubble air diffuser tube”. The diffused gas 3 may be a diffused tube made of a tubular member such as a diffused cylinder made of a porous synthetic resin or ceramic or a flexible tube provided with a large number of slits. Further, the air diffuser 3 may be a diffuser plate made of a plate-shaped member such as a square shape or a round shape.

[Second Embodiment]
FIG. 2 is a schematic explanatory view showing a water treatment system including an air diffuser according to a second embodiment of the present invention. Fig.2 (a) is a top view of the water treatment system of the 2nd Embodiment of this invention, FIG.2 (b) is a side view of the water treatment system of the 2nd Embodiment of this invention. (II-II arrow view in FIG. 2a)
In the air diffuser 1b according to the second embodiment, the air diffuser 3 according to the first embodiment is replaced with air diffusers 5a, 5b, 5c, 5d, 5e, and 5f that have different amounts of air to be discharged. It is.

  As the diffused gas 5a, 5b, 5c, 5d, 5e, and 5f, a structure is selected in which the amount of air discharged is different. For example, the diffused gas 5a, 5b, 5c, 5d, 5e, and 5f may have a structure in which the number and size of air diffusers (slits and holes) for discharging air are different, and the amount of air to be supplied is individually adjusted. A flow rate control mechanism may be provided. Further, as shown in FIG. 2a, the lengths of the diffused gases 5a, 5b, 5c, 5d, 5e, and 5f may be different. Further, different forms may be used as the diffused gases 5a, 5b, 5c, 5d, 5e, and 5f. For example, a combination of a tubular member and a plate member may be used.

  As shown in FIG. 2b, when the air is diffused, the amount of air discharged in the order of the diffused gas 5a, 5b, 5c, 5d, 5e, and 5f is reduced to increase the strong upward flow from the diffuser tank side wall 2a side. This upward flow reaches the water surface, pushes the scum S on the water surface toward the diffuser tank side wall 2b, then flows downward through the gap G, and from the diffuser tank side wall 2b side to the diffuser tank A swirling flow toward the bottom of 2 is generated.

[Arrangement method of air diffuser]
The arrangement method of the air diffuser according to the present invention is a method of arranging an air diffuser comprising a plurality of air diffusers, wherein the air diffuser is adjacent to one side wall of the air diffuser and the air diffuser The air diffuser is disposed so as to be densely packed toward the one side wall, and the amount of air diffused from the air diffuser is What is necessary is just to make it increase gradually as it goes to one side wall from the other side wall.
Specifically, the diffused gas 3 close to the side wall 2a of the air diffusion tank is arranged densely, and the arrangement interval of the diffused gas 3 is arranged so as to become sparse as it approaches the side wall 2b.
With this air diffuser arrangement method, a strong swirl flow without reducing the oxygen transfer efficiency in an air diffuser that improves the oxygen transfer efficiency by relatively reducing the amount of air supplied as in the ultrafine bubble diffuser. It is possible to prevent the accumulation of scum on the water surface.

<Water surface velocity simulation of diffuser>
A water flow velocity simulation was performed on the water treatment system of the present invention. The arrangement of the diffused gas 3 was simulated in the same manner as in the first embodiment with seven diffused gases 3 constituting the diffused unit 4. The result is shown in FIG.
FIG. 3b shows a result of a water surface flow velocity simulation in a conventional air diffuser in which the air diffused is arranged at equal intervals. In this simulation, the number of diffused gas in FIGS. 3a and 3b is the same.

  The simulation was performed using ANSYS general-purpose fluid simulation software “Fluent”. The calculation results shown in FIG. 4 are the results of an aeration tank width of 5.5 m, a tank length of 8.6 m, a tank water depth of 5.0 m, and an aeration apparatus installation water depth of 4.0 m. The tank shape, the aeration device installation water depth, the aeration device layout, etc. are not limited.

  It can be seen from FIG. 3a that in the water treatment system of the present invention, a strong flow in a certain direction is formed from one side wall to the other side wall on the water surface. On the other hand, it can be seen from FIG. 3b that in the conventional diffuser in which the diffused gas is arranged at equal intervals, the flow on the water surface is diffused as a whole.

Moreover, in FIG. 4, the water surface average flow velocity in the water treatment system of the 1st Embodiment of this invention and the water treatment system provided with the conventional swirling diffuser which arranged the diffused gas at equal intervals was compared. The graph is shown.
The water surface average flow velocity in the air diffuser of the present invention was 1.5 times faster than the water surface average flow velocity in the air diffuser in which the air diffused was arranged at equal intervals.

  From the results of FIGS. 3 and 4, the amount of air diffused from the air diffuser gradually decreases or increases from one side wall of the air diffusion tank toward the other side wall. A constant direction of flow is generated. As a result, the scum on the water surface can be washed away and scum accumulation can be prevented.

  The water treatment system and the arrangement method of the air diffuser according to the present invention can be used in an aerobic microorganism treatment tank for organic sludge such as a sewage treatment plant or an organic wastewater such as a food factory or a pharmaceutical factory, and a treatment method thereof. it can.

1a, 1b Air diffuser, 2 Air diffuser, 2a, 2b Side wall, 3 Air diffuser, 4 Air diffuser unit, 5a, 5b, 5c, 5d, 5e, 5f Air diffuser, 6 Header tube, 7 Air supply tube, 10 Water Treatment system, G gap, Hu upper hunch, Hs lower hunch, B blower, W treated water, S scum

Claims (4)

  A water treatment system comprising an air diffuser installed near a side wall of the air diffuser and the other side wall of the air diffuser to form a gap between the air diffuser, The air diffusion device is characterized in that the amount of air diffusion gradually decreases or increases from the other side wall toward the one side wall.   2. The water treatment system according to claim 1, wherein the air diffuser gradually increases in the amount of air diffused from the other side wall toward the one side wall.   The water treatment system according to claim 2, wherein the air diffuser includes a plurality of air diffused gas, and the gas diffused gas is arranged so as to be concentrated toward the one side wall. A method of disposing an air diffuser comprising a plurality of air diffusers in an air diffuser, wherein the air diffuser is adjacent to one side wall of the air diffuser and is connected to the other side wall of the air diffuser. A method for arranging a diffuser, wherein the diffuser is arranged so as to form a gap therebetween, and the diffused gas is arranged so as to be densely packed toward the one side wall.