JP6848642B2 - Membrane separation activated sludge device and water treatment method - Google Patents

Description

The present invention relates to a membrane separation activated sludge apparatus and a water treatment method.

Industrial wastewater and domestic wastewater are treated to remove organic substances and the like contained in the wastewater, and then reused as industrial water or discharged into rivers and the like. Examples of the treatment method for industrial wastewater include the activated sludge method. The activated sludge method is a method of decomposing organic substances and the like by aeration and aerobic microorganisms.

Further, in recent years, treatment by the membrane separation activated sludge (MBR) method, which is a combination of treatment by the activated sludge method and membrane filtration by a separation membrane module, has come to be performed. In the treatment by the MBR method, as the membrane filtration is continued, organic substances and the like are deposited on the surface of the separation membrane, which may cause a decrease in the filtration flow rate and an increase in the intermembrane differential pressure.

In response to this problem, in the treatment by the MBR method, the deposition of organic substances on the membrane surface is suppressed by the air diffuser tube installed below the membrane module. Specifically, the deposition of organic substances and the like on the membrane surface is suppressed by vibrating the membrane itself by the impact when the bubbles generated from the air diffuser come into contact with the membrane surface or the water flow accompanying the generation of the bubbles.
From the viewpoint of cleanability of the film surface, it is preferable that the size of the bubbles is large. Patent Document 1 discloses a siphon type air diffuser that efficiently discharges large bubbles.

Japanese Unexamined Patent Publication No. 2003-340250

However, since the siphon type air diffuser described in Patent Document 1 cannot adjust the size and intermittent time of bubbles, it continues to emit huge bubbles even in a situation where high detergency is not required. Therefore, the energy efficiency may be lowered in the treatment by the MBR method to which the above siphon type air diffuser is applied. In addition, as the size of the bubbles increases, the efficiency of dissolution in water decreases, so oxygen required for biological treatment is insufficient, and the properties of sludge and the quality of treated water may deteriorate.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a siphon type air diffuser and a membrane separation activated sludge device capable of adjusting the size and intermittent time of bubbles, and a water treatment method. And.

The present invention has the following configurations.
[1] A siphon type air diffuser that aerates.
A siphon chamber for storing air, including a first siphon chamber and a second siphon chamber on the downstream side of the first siphon chamber, and a communication section connecting the first siphon chamber and the second siphon chamber. A pipe body portion formed inside, a diffuser hole is formed downstream of the siphon chamber, and a treated water inflow port is formed upstream of the siphon chamber.
An air supply means for supplying air to the siphon chamber and
A siphon type air diffuser including an opening amount adjusting means for adjusting the opening amount of the treated water inlet.
[2] The treated water inflow port is formed at the bottom of the pipe body, and the treated water inlet is formed.
The opening amount adjusting means includes an elevating means for raising and lowering the pipe main body portion.
With the pipe body lowered by the elevating means, the treated water inflow port is blocked by the bottom surface of the tank in which the siphon type air diffuser is installed.
The siphon type air diffuser according to [1], wherein the treated water inflow port is opened apart from the bottom surface of the tank in a state where the pipe main body is raised by the elevating means.
[3] The treated water inflow port is formed at the bottom of the pipe body, and the treated water inlet is formed.
The opening amount adjusting means includes a lid member that closes the treated water inflow port and an elevating means that raises and lowers the pipe body.
With the pipe body lowered by the elevating means, the treated water inflow port is closed with the lid member.
The siphon type air diffuser according to [1], wherein the treated water inflow port is opened apart from the lid member in a state where the pipe main body is raised by the elevating means.
[4] The opening amount adjusting means includes a lid member that closes the treated water inflow port and a lid member.
The siphon type air diffuser according to [1], which includes a drive unit for driving the lid member.
[5] The siphon type air diffuser according to any one of [1] to [4].
A membrane module that separates sludge-containing treated water containing activated sludge into a membrane,
A membrane separation activated sludge device including the siphon type air diffuser and a membrane separation tank in which the membrane module is installed.
[6] An activated sludge treatment step of treating raw water with activated sludge using activated sludge, and
It has a membrane separation step of separating the sludge-containing treated water obtained in the activated sludge treatment step by a membrane separation treatment.
A water treatment method using the membrane separation activated sludge apparatus according to [5] in the membrane separation step.

By using the siphon type air diffuser and the membrane separation activated sludge device of the present invention, the size of bubbles and the intermittent time can be adjusted.
According to the water treatment method of the present invention, water treatment can be performed while adjusting the size of bubbles and the intermittent time.

It is a schematic diagram which showed an example of the water treatment apparatus used for the water treatment method of this invention. It is a perspective view which showed an example of the structure other than the elevating means of the siphon type air diffuser of this invention. FIG. 3 is a sectional view taken along line III-III of the siphon type air diffuser of FIG. It is sectional drawing explaining the operation mechanism of the siphon type air diffuser of FIG. It is sectional drawing explaining the operation mechanism of the siphon type air diffuser of FIG. It is a schematic schematic diagram explaining the operation mechanism of the siphon type air diffuser of FIG. It is a schematic schematic diagram explaining the operation mechanism of the siphon type air diffuser of FIG. It is sectional drawing explaining the operating mechanism of another example of the siphon type air diffuser of this invention. It is sectional drawing which showed the other example of the siphon type air diffuser of this invention.

Hereinafter, an example of the embodiment of the present invention will be described with reference to the drawings. It should be noted that the dimensions and the like of the figures illustrated in the following description are examples, and the present invention is not necessarily limited thereto, and the present invention can be appropriately modified without changing the gist thereof. ..

[Water treatment equipment]
Hereinafter, an example of the water treatment apparatus used in the water treatment method of the present invention will be described with reference to FIG.
As shown in FIG. 1, the water treatment device 1000 of the present embodiment includes an activated sludge treatment tank 11 and a membrane separation active sludge device 100 (hereinafter, “MBR device 100”) provided after the activated sludge treatment tank 11. It is provided with a treatment water tank 41 provided after the MBR device 100. Further, although not shown, the water treatment device 1000 includes a flow rate adjusting tank for adjusting the flow rate of raw water flowing into the activated sludge treatment tank 11, a drawing pump for drawing excess sludge from the MBR device 100, and a chemical solution in the MBR device 100. It is provided with a liquid feeding means for sending diluted water, a discharging means for discharging treated water from the treated water tank 41 to a factory, a river, or the like.

The activated sludge treatment tank 11 is filled with activated sludge for performing activated sludge treatment.
The activated sludge treatment tank 11 is connected to a first flow path 12 and a second flow path 13. The first flow path 12 is a flow path for flowing raw water discharged from a factory, a household, or the like into the activated sludge treatment tank 11. The second flow path 13 is a flow path for flowing sludge-containing treated water (treated water) discharged from the activated sludge treatment tank 11 into the MBR device 100.

An air diffuser 14 is installed in the activated sludge treatment tank 11 in order to maintain the inside of the tank under aerobic conditions.
The air diffuser 14 includes an air diffuser 14a that diffuses air into the activated sludge treatment tank 11, an introduction pipe 14b that supplies air to the air diffuser 14a, and a blower 14c that supplies air.
The air diffuser tube 14a is not particularly limited as long as it can discharge the air supplied from the blower 14c upward, and examples thereof include a single tube with a hole and a membrane type.

The treated water tank 41 stores the treated water after the sludge-containing treated water is membrane-separated.

(Membrane separation activated sludge device)
The MBR device 100 includes a membrane separation tank 21, a membrane module 22, and a siphon type air diffuser 1 provided below the membrane module 22. Further, it is preferable to further include a detection unit 26 and a control unit 28 connected to the detection unit 26. The second flow path 13 is connected to the membrane separation tank 21. The membrane module 22 and the siphon type air diffuser 1 are arranged in the membrane separation tank 21.

The membrane separation tank 21 stores sludge-containing treated water containing activated sludge and biologically treated water sent from the activated sludge treatment tank 11.

A sludge returning means 30 is connected to the membrane separation tank 21 and the activated sludge treatment tank 11. The sludge returning means 30 returns a part of the sludge-containing treated water from the membrane separation tank 21 to the activated sludge treatment tank 11.
The sludge returning means 30 includes a fourth flow path 31. The fourth flow path 31 is a flow path in which a part of the sludge-containing treated water is discharged from the membrane separation tank 21 and flows into the activated sludge treatment tank 11.
A pump 31a is installed in the fourth flow path 31. As a result, a part of the sludge-containing treated water in the membrane separation tank 21 can be returned from the membrane separation tank 21 to the activated sludge treatment tank 11.

The membrane module 22 separates the sludge-containing treated water containing activated sludge into a membrane. The membrane module 22 includes a separation membrane, and the sludge-containing treated water is solid-liquid separated (membrane separation) into biologically treated water and activated sludge by this separation membrane.

The separation membrane is not particularly limited as long as it has a separation ability, and examples thereof include a hollow fiber membrane, a flat membrane, a tubular membrane, and a monolith type membrane. Among these, a hollow fiber membrane is preferable because it has a high volume filling rate.

When a hollow fiber membrane is used as the separation membrane, examples of the material thereof include cellulose, polyolefin, polysulfone, polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE). Among these, PVDF and PTFE are preferable as the material of the hollow fiber membrane from the viewpoint of chemical resistance and resistance to pH change.
When a monolith type membrane is used as the separation membrane, it is preferable to use a ceramic membrane.

The average pore diameter of the fine pores formed in the separation membrane is about 0.001 to 0.1 μm for a membrane generally called an extraneous separation membrane, and about 0.1 to 1 μm for a membrane generally called a precision separation membrane. .. In this embodiment, it is preferable to use a separation membrane having an average pore size within the above range.

A third flow path 33 is connected to the membrane module 22. The third flow path 33 is a flow path for discharging the treated water that has passed through the separation membrane from the membrane separation tank 21 and flowing it into the treated water tank 41.
A pump 33a is installed in the third flow path 33. As a result, the treated water that has passed through the separation membrane of the membrane module 22 can be discharged from the membrane separation tank 21.

As shown in FIGS. 1 to 3, the siphon type air diffuser tube 1 includes a tube main body 50, an air supply means 52, and an opening amount adjusting means 54.
The tube main body 50 is a box-shaped housing formed by combining a plurality of plate-shaped members, and all of them have a rectangular upper plate 1A, four side plates 1B, a bottom plate 1C, and a first plate. It has one partition wall 4a and a second partition wall 4b.

The four side plates 1B are provided so as to extend downward from each of the four sides of the upper plate 1A. An air diffuser hole 6 extending along the side plate 1B is formed in a portion of the upper plate 1A near one side plate 1B. The first partition wall 4a is provided so as to extend downward from the upper plate 1A so that the side plates 1B and the side plates 1B face each other with the air diffuser hole 6 interposed therebetween.

The length of the bottom plate 1C is smaller than that of the top plate 1A. The bottom plate 1C closes approximately half of the lower opening end of the tubular portion formed by the four side plates 1B so as to extend inward from the lower end of the side plate 1B on the side where the air diffuser hole 6 is formed. It is provided in. The portion of the opening on the lower side of the pipe body 50 that is not blocked by the bottom plate 1C is the treated water inflow port 7.
The second partition wall 4b is provided so as to extend upward from an end portion of the bottom plate 1C located on the opposite side of the first partition wall 4a from the air diffuser hole 6. The surfaces of the first partition wall 4a and the second partition wall 4b face each other.
In the pipe main body 50, assuming the flow of wastewater from the treated water inflow port 7 to the air diffuser hole 6, the treated water inflow port 7 side is referred to as “upstream” and the air diffuser hole 6 side is referred to as “downstream”.

The siphon chamber 2 stores air. The siphon chamber 2 has a height _{from the upper end 4b 1} of the second partition wall 4b to the lower end 4a ₁ of the first partition wall 4a on the treated water inflow port 7 side of the first partition wall 4a in the pipe main body 50. Refers to space. The siphon chamber 2 is divided into a first siphon chamber 2A and a second siphon chamber 2B by a second partition wall 4b.

The upper part of the first siphon chamber 2A and the upper part of the second siphon chamber 2B are communicated with each other by the communication portion 5. The portion from the second siphon chamber 2B to the air diffuser hole 6 in the pipe main body 50 is the path 4. A part of the first partition wall 4a faces the siphon chamber 2 and the route 4. In other words, a part of the first partition wall 4a separates the siphon chamber 2 from the path 4. A part of the second partition wall 4b faces the siphon chamber 2. _{The upper end 4b 1} of the second partition wall 4b is located at least above _{the lower end 4a 1} of the first partition wall 4a. The treated water inflow port 7 is formed at the bottom of the pipe main body 50, and is located below _{the lower end 4a 1 of the first partition wall 4a.}

As described above, inside the pipe body 50, the first siphon chamber 2A, the communication portion 5, the second siphon chamber 2B, and the path 4 are formed in this order from upstream to downstream. An air diffuser hole 6 is formed downstream of the siphon chamber 2 in the pipe body 50, and a treated water inflow port 7 is formed upstream of the siphon chamber 2. The treated water inlet 7 communicates the outside of the siphon type air diffuser 1 with the siphon chamber 2.

The plan view shape of the air diffuser hole 6 is a long rectangular shape. The area of the air diffuser hole 6 in a plan view is preferably 25 cm ² or less, and more preferably 20 cm ² or less. The length of the plan view shape in the longitudinal direction is preferably 25 cm or less, more preferably 20 cm or less.

The siphon type air diffuser 1 is provided at a position where the air diffuser holes 6 overlap between the adjacent separation membranes in the membrane module 22 when the membrane separation tank 21 is viewed in a plan view.

The air supply means 52 is a means for supplying air to the siphon chamber 2. The air supply means 52 includes an introduction pipe 1a for supplying air to the siphon chamber 2 in the pipe main body 50, and a blower 1b for supplying air.
The introduction pipe 1a penetrates in the thickness direction of the upper plate 1A on the side of the first siphon chamber 2A with respect to the second partition wall 4b of the upper plate 1A. An air supply port 3 is formed at the lower end of the introduction pipe 1a. The air supply port 3 formed in the introduction pipe 1a is located below _{the lower end 4a 1 of the first partition wall 4a.} That is, the air supply port 3 is arranged outside the siphon chamber 2 capable of storing air.

The cross-sectional shape of the introduction pipe 1a is not particularly limited. For example, when the cross-sectional shape of the introduction pipe 1a is circular, the inner diameter of the introduction pipe 1a is preferably 4 mm or more and 25 mm or less, more preferably 4.5 mm or more and 15 mm or less, further preferably 5 mm or more and 10 mm or less, and 5.5 mm or more. Less than 8.5 mm is particularly preferred. It is preferable that the inner diameter of the introduction pipe 1a is 4 mm or more because sludge is less likely to be clogged. In this embodiment, the inner diameter of the introduction pipe 1a is constant.

The opening amount adjusting means 54 is a means for adjusting the opening amount of the treated water inflow port 7. The opening amount adjusting means 54 of this example includes an elevating means 55 for raising and lowering the pipe main body 50.
The mechanism for raising and lowering the pipe body 50 in the raising and lowering means 55 is not particularly limited as long as the pipe body 50 can be raised and lowered as desired.

In the present embodiment, the bottom surface portion 21a of the membrane separation tank 21 serves as a lid that closes the treated water inflow port 7 formed at the bottom portion of the pipe body portion 50. As shown in FIG. 4, in a state where the pipe body 50 is lowered to the bottom surface 21a of the membrane separation tank 21 by the opening amount adjusting means 54, the treated water inlet of the pipe body 50 is provided by the bottom surface 21a of the membrane separation tank 21. 7 is blocked. Further, as shown in FIG. 5, when the pipe body 50 is raised by the opening amount adjusting means 54, the treated water inflow port 7 of the pipe body 50 is opened apart from the bottom surface 21a of the membrane separation tank 21. To.

Hereinafter, the operating mechanism of the siphon type air diffuser 1 will be described.
As shown in FIG. 5, the pipe body 50 is raised by the opening amount adjusting means 54, and the treated water inflow port 7 of the pipe body 50 is opened apart from the bottom surface 21a of the membrane separation tank 21. Before the start of operation in this state, as shown in FIG. 6A, the siphon chamber 2, the communication portion 5 and the path 4 in the pipe main body 50 are filled with sludge-containing treated water B (water to be treated). There is.

Air A is continuously supplied to the siphon chamber 2 from the air supply port 3 of the introduction pipe 1a in the air supply means 52. When the air A is continuously supplied from the air supply port 3, the sludge-containing treated water B in the siphon chamber 2 is pushed out from the air diffuser hole 6 and the treated water inflow port 7 as shown in FIG. The liquid level S in the chamber 2 gradually drops. Further, when the air A is continuously supplied from the air supply port 3 and the height of the liquid level S _{becomes lower than the lower end 4a 1} of the first partition wall 4a, sludge is discharged from the treated water inflow port 7 as shown in FIG. 6 (c). At the same time that the contained treated water B flows into the pipe main body 50, the air A stored in the siphon chamber 2 and the communication portion 5 moves to the path 4 and is discharged from the air diffuser hole 6 at once. As a result, as shown in FIG. 6A, the siphon chamber 2, the communication portion 5, and the path 4 in the pipe main body 50 return to the state of being filled with the sludge-containing treated water B. Then, the states of FIGS. 6A to 6C are repeated.

In this way, in the siphon type air diffuser 1 in which the pipe body 50 is raised by the opening amount adjusting means 54 and the treated water inflow port 7 of the pipe body 50 is opened, large bubbles are intermittently released. To. The amount of air to be stored is theoretically equal to the volume of the siphon chamber 2 and the communication portion 5, and the size of the bubbles to be formed and the intermittent time are constant.

Further, as shown in FIG. 4, the pipe body 50 is lowered by the opening amount adjusting means 54, and the pipe body 50 is provided by the bottom surface 21a of the tank in which the siphon type air diffuser 1 is installed, that is, the membrane separation tank 21. It is assumed that the treated water inflow port 7 is blocked. Before the start of operation in this state, as shown in FIG. 7A, the siphon chamber 2, the communication portion 5 and the path 4 in the pipe main body 50 are filled with the sludge-containing treated water B.

Air A is continuously supplied to the siphon chamber 2 from the air supply port 3 of the introduction pipe 1a in the air supply means 52. When the air A is continuously supplied from the air supply port 3, the sludge-containing treated water B in the siphon chamber 2 is pushed out from the air diffuser hole 6 as shown in FIG. 7 (b), and the liquid level S in the siphon chamber 2 S. Gradually descends. Further, when the air A is continuously supplied from the air supply port 3 and the height of the liquid level S _{becomes lower than the lower end 4a 1} of the first partition wall 4a, as shown in FIG. 7C, the treated water inflow port 7 is used. Since the sludge-containing treated water B does not flow in, the air A stored in the siphon chamber 2 and the communication portion 5 continuously becomes fine bubbles and moves to the path 4, and is continuously discharged from the air diffuser hole 6. To. In this way, in the siphon type air diffuser 1 in which the pipe body 50 is lowered by the opening amount adjusting means 54 and the treated water inflow port 7 of the pipe body 50 is closed, small bubbles are continuously released. To.

In the siphon type air diffuser 1, as described above, the pipe body 50 is raised to open the treated water inflow port 7, or the pipe body 50 is lowered to close the treated water inlet 7. By doing so, it is possible to intermittently release large-sized bubbles or continuously release small-sized bubbles. In this way, in the siphon type air diffuser 1, the size of the bubbles and the intermittent time can be adjusted.

The detection unit 26 detects at least one of the intermembrane differential pressure in the membrane module 22 and the dissolved oxygen concentration of the sludge-containing treated water. The detection unit 26 is not particularly limited, and a known detector can be used.

The control unit 28 determines the opening amount of the treated water inflow port 7 based on the detection result of the detection unit 26, and controls the movement of the opening amount adjusting means 54.

[Water treatment method]
Hereinafter, as an example of the water treatment method of the present invention, the water treatment method using the water treatment apparatus 1000 described above will be described. The water treatment method of the present embodiment includes an activated sludge treatment step of treating raw water with activated sludge using activated sludge, and a membrane separation step of separating the sludge-containing treated water obtained in the activated sludge treatment step. ing.

(Activated sludge treatment process)
In the water treatment method using the water treatment device 1000, wastewater (raw water) such as industrial wastewater and domestic wastewater discharged from factories and households is allowed to flow into the activated sludge treatment tank 11 through the first flow path 12, and the activated sludge treatment tank Treated with activated sludge in No. 11 to obtain biologically treated water. The sludge-containing treated water (treated water) after the treatment flows into the membrane separation tank 21 of the MBR device 100 through the second flow path 13.

(Membrane separation process)
In the membrane separation tank 21 of the MBR apparatus 100, the sludge-containing treated water (water to be treated) containing activated sludge and biologically treated water is subjected to membrane separation treatment by the membrane module 22. During the membrane separation process, aeration is performed by the siphon type air diffuser 1.

For example, when the dissolved oxygen concentration of the sludge-containing treated water B detected by the detection unit 26 is lower than a predetermined concentration, the control unit 28 gives priority to setting the inside of the membrane separation tank 21 to an appropriate aerobic condition. A decision is made to close the treated water inlet 7. Then, the pipe body 50 is lowered by the elevating means 55 of the opening amount adjusting means 54 to close the treated water inflow port 7, and small bubbles having a high oxygen dissolution efficiency are continuously released.

Further, for example, when the intermembrane differential pressure in the membrane module 22 detected by the detection unit 26 is larger than a predetermined differential pressure, the control unit 28 suppresses the deposition of organic substances or the like on the separation membrane surface of the membrane module 22. It is decided to open the treated water inlet 7 in order to give priority to. Then, the pipe main body 50 is raised by the elevating means 55 of the opening amount adjusting means 54 to open the treated water inflow port 7, and large-sized bubbles are intermittently released.

As described above, in the siphon type air diffuser 1, the membrane separation treatment can be performed while adjusting the size of the bubbles and the intermittent time according to the treatment status.
When the pipe body 50 is raised or lowered by the raising or lowering means 55 of the opening amount adjusting means 54, the membrane module 22 may be raised or lowered at the same time as the pipe body 50, and the position of the membrane module is fixed. The pipe body 50 may be raised or lowered.

A part of the sludge-containing treated water B is returned from the membrane separation tank 21 to the activated sludge treatment tank 11 by the sludge returning means 30. The treated water after the sludge-containing treated water B is membrane-separated by the membrane module 22 is sent to the treated water tank 41 through the third flow path 33 and stored. The treated water stored in the treated water tank 41 can be reused as industrial water or discharged into a river or the like.

As described above, in the present invention, the siphon type air diffuser is provided with an opening amount adjusting means for adjusting the opening amount of the treated water inflow port formed in the pipe body. By adjusting the opening amount of the treated water inlet of the siphon type air diffuser by the opening amount adjusting means, it is possible to intermittently release large-sized bubbles or continuously release small-sized bubbles. As described above, in the present invention, for example, depending on the circumstances such as giving priority to suppressing the deposition of organic substances on the surface of the separation membrane of the membrane module or giving priority to setting the inside of the tank to an appropriate aerobic condition, the bubbles are generated. Since the size and intermittent time can be adjusted, water treatment can be performed stably.

The siphon type air diffuser of the present invention is not limited to the siphon type air diffuser 1 described above. The siphon type air diffuser is not limited to the one that closes the treated water inflow port 7 by using the bottom surface portion 21a of the membrane separation tank 21, and is, for example, an opening amount adjusting means further provided with a lid member in addition to the elevating means. It may be a siphon type air diffuser that closes or opens the treated water inflow port by the lid member by raising or lowering the pipe body.

Specifically, the siphon type air diffuser of the present invention may be the siphon type air diffuser 8 illustrated in FIG. The same parts as those in FIG. 4 in FIG. 8 are matched with each other and the description thereof will be omitted.
The siphon type air diffuser tube 8 includes a tube main body 50, an air supply means 52, and an opening amount adjusting means 54A. The siphon type air diffuser 8 has the same embodiment as the siphon type air diffuser 1 except that the opening amount adjusting means 54A is provided instead of the opening amount adjusting means 54. The opening amount adjusting means 54A is different from the opening amount adjusting means 54 except that the elevating means 55 is provided with a lid member 53 arranged below the treated water inflow port 7 of the pipe main body 50 to close the treated water inflow port 7. It is the same.

In the siphon type air diffuser 8, when the pipe body 50 is raised by the elevating means 55 and the treated water inflow port 7 is separated from the lid member 53 and opened, the size is large by the same mechanism as the siphon type air diffuser 1. Bubbles are released intermittently. Further, when the pipe body 50 is lowered by the elevating means 55 and the treated water inflow port 7 is closed by the lid member 53, small bubbles are continuously released by the same mechanism as the siphon type air diffuser 1. ..
As described above, even when the siphon type air diffuser 8 is used, the membrane separation treatment can be performed while adjusting the size of the bubbles and the intermittent time according to the treatment condition.

Further, in the siphon type air diffuser of the present invention, the opening amount adjusting means is not limited to the one provided with the raising / lowering means for raising / lowering the pipe main body, and the lid member for closing the treated water inflow port and the driving for driving the lid member. It may be provided with a part. Specifically, the siphon type air diffuser 9 illustrated in FIG. 9 may be used. The same parts as those in FIG. 3 in FIG. 9 are matched with each other, and the description thereof will be omitted.

The siphon type air diffuser 9 includes a pipe body 50, an air supply means 52, and an opening amount adjusting means 54B. The siphon type air diffuser 9 has the same embodiment as the siphon type air diffuser 1 except that the opening amount adjusting means 54B is provided instead of the opening amount adjusting means 54.

The opening amount adjusting means 54B is a means for adjusting the opening amount of the treated water inflow port 7, and includes a lid member 56 for closing the treated water inflow port 7 and a driving unit 58 for driving the lid member 56.

In the siphon type air diffuser 9, the lid member 56 can be driven by the drive unit 58 in the opening amount adjusting means 54B, and the opening amount of the treated water inflow port 7 can be adjusted by the lid member 56. In the siphon type air diffuser 9, when the treated water inflow port 7 is completely opened, large bubbles are intermittently released by the same mechanism as the siphon type air diffuser 1. When the entire treated water inflow port 7 is closed by the lid member 56, small-sized bubbles are continuously discharged by the same mechanism as the siphon type air diffuser 1. Further, when only a part of the treated water inflow port 7 is closed by the lid member 56, the treated water flow is in a range between the state where the treated water inflow port 7 is completely opened and the state where the treated water inflow port 7 is completely closed. The size of the bubbles and the intermittent time change according to the opening amount of the inlet 7.
As described above, even when the siphon type air diffuser 9 is used, the membrane separation treatment can be performed while adjusting the size of the bubbles and the intermittent time according to the treatment condition.

Further, in the siphon type air diffuser of the present invention, the introduction pipe of the air supply means penetrates in the thickness direction of the side plate arranged on the first siphon chamber side so as to face the second partition wall 4b in the pipe main body. You may be doing it. The inner diameter of the introduction pipe 1a is not limited to a constant value, and may be gradually decreased in a direction away from the upper plate 1A. In this case, it becomes difficult for sludge to flow into the introduction pipe 1a, and it becomes easy to prevent sludge from being clogged in the introduction pipe 1a.
Further, the membrane separation activated sludge device does not have to include a control unit.
Further, the water treatment apparatus may be one in which the membrane separation tank 21 is provided in the activated sludge treatment tank 11.

1,8,9 ... Siphon type air diffuser, 2 ... Siphon room, 2A ... First siphon room, 2B ... Second siphon room, 5 ... Communication part, 6 ... Air diffuser hole, 7 ... Treated water inlet, 11 ... Activated Sludge treatment tank, 21 ... Membrane separation tank, 21a ... Bottom part, 22 ... Membrane module, 41 ... Treatment water tank, 50 ... Pipe body part, 52 ... Air supply means, 53 ... Lid member, 54, 54A ... Opening amount adjusting means , 55 ... Elevating means, 56 ... Lid member, 58 ... Drive unit, 100 ... Membrane separation activated sludge device, 1000 ... Water treatment device.

Claims (3)

A membrane separation activated sludge device equipped with a siphon type air diffuser and a membrane separation tank in which a membrane module is installed.
The siphon diffusing pipe is,
A siphon chamber for storing air, including a first siphon chamber and a second siphon chamber on the downstream side of the first siphon chamber, and a communication section connecting the first siphon chamber and the second siphon chamber. A pipe body portion formed inside, a diffuser hole is formed downstream of the siphon chamber, and a treated water inflow port is formed upstream of the siphon chamber.
An air supply means for supplying air to the siphon chamber and
It is provided with an opening amount adjusting means for adjusting the opening amount of the treated water inflow port , and
The opening amount adjusting means includes a lid member that closes the treated water inflow port and
A membrane separation activated sludge device including a driving unit for driving the lid member. The membrane separation activated sludge device further includes a detection unit and a control unit.
The detection unit detects at least one of the intermembrane differential pressure in the membrane module and the dissolved oxygen concentration of the sludge-containing treated water.
The membrane separation activated sludge device according to claim 1, wherein the control unit controls the opening adjusting means based on the detection result of the detection unit. Activated sludge treatment process that treats raw water with activated sludge using activated sludge,
It has a membrane separation step of separating the sludge-containing treated water obtained in the activated sludge treatment step by a membrane separation treatment.
A water treatment method using the membrane separation activated sludge apparatus according to claim 1 or 2 in the membrane separation step.

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