JP2019037917A - Water treatment apparatus and water treatment method - Google Patents

Abstract

To provide a water treatment apparatus and a water treatment method capable of performing water treatment stably by preventing occurrence of blockage of filtered water.SOLUTION: A water treatment apparatus 10 includes: a filtered water tank 11, a membrane module 20, first lines 31a, 32a, second lines 31b, 32b, check valves 14, 15, and valves 16, 17. The membrane module 20 includes: a container 21a having openings each at both ends; a hollow fiber membrane 21b disposed in the container 21a; and sealing parts 21c which fix both ends of the hollow fiber membrane 21b to the container 21a to seal the openings each at both ends of container 21a. A control unit 30 operates the valves 16 and 17 to control a flow direction of to-be-filtered water W. Connection members 22 and 23 are fitted to both ends of the container 21a. A/B satisfies the following relational expression (1): A/B≤2.0.....(1), where A is a diameter of an end face of the sealing part 21c, and B is an inner diameter of the container 21a at a predetermined distance from the end face of the sealing part 21c along a long axis direction of the hollow fiber membrane.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a water treatment apparatus and a water treatment method for performing water treatment by internal pressure filtration.

  Conventionally, membrane modules equipped with hollow fiber membranes have been used for purification of water such as clarification of river water and groundwater, clarification of industrial water, drainage and sewage treatment, seawater desalination pretreatment, etc. Yes. And, in a situation where it is required to supply a large amount of safe water regularly, various components contained in the raw water that is the treated water are separated more efficiently and more economically, It is necessary to continuously supply clean water.

  For this reason, in recent years, a membrane module including a water treatment membrane having a high physical strength made of various materials has been proposed. For example, Patent Document 1 discloses an operation method and a separation membrane device for a separation membrane module that generates a flow in the opposite direction in order to efficiently remove turbidity accumulated in a raw water spacer wound around a spiral membrane element. It is disclosed.

Japanese Patent Laid-Open No. 2004-141846

  However, the conventional separation membrane module operating method and separation membrane apparatus have the following problems.

  That is, in the method and apparatus disclosed in the above publication, although it is described that the flow is generated in the reverse direction in the spiral membrane element, a membrane module including a hollow fiber membrane is used instead of the spiral membrane element. In such a case, the raw water may become clogged and it may be difficult to perform stable water treatment.

  An object of the present invention is to provide a water treatment apparatus and a water treatment method capable of preventing water from being filtered off and stably performing water treatment.

  The water treatment apparatus according to the first invention includes a water tank to be filtered, a membrane module, a first line, a second line, and a flow direction selector. The filtered water tank stores the filtered water. The membrane module includes a cylindrical molded body having an opening, a hollow fiber membrane disposed in the cylindrical molded body, and an end of the hollow fiber membrane fixed to the cylindrical molded body to seal the opening of the cylindrical molded body. It has a sealing part and performs membrane filtration by internal pressure filtration outside the water tank to be filtered. A 1st line connects a to-be-filtered water tank and a membrane module, and supplies to-be-filtered water from a to-be-filtered water tank to a membrane module. A 2nd line connects a membrane module and a to-be-filtered water tank, and returns the to-be-filtered water which passed the membrane module to a to-be-filtered water tank. A flow direction selection part switches the flow direction of the to-be-filtered water of the axial direction in a membrane module to a forward direction or the opposite reverse direction. When the diameter of the end face of the sealing part is A, and the inner diameter of the cylindrical molded body at a predetermined distance along the long axis direction of the hollow fiber membrane from the end face of the sealing part is B, A / B is as follows: Equation (1) is satisfied.

A / B ≦ 2.0 (1)
Here, the water to be filtered can be flowed in both directions by switching in the forward direction or the reverse direction with respect to the membrane module connected through the water tank to be filtered and the first line and the second line. In a possible water treatment apparatus, when the diameter of the end face of the sealing part is A, and the inner diameter of the cylindrical molded body at a predetermined distance along the long axis direction of the hollow fiber membrane from the end face of the sealing part is B, Define the range of A / B.

  In addition, about the diameter A, the diameter of the end surface of a sealing part is pointed out, In the case where the pipe | tube which has a water collection function, the support body for strength support, etc. are inserted in the sealing part of both ends. Also, let A be the diameter of the end face of the sealing portion.

  Here, the membrane module is such that the opening of a cylindrical molded body provided with a hollow fiber membrane is sealed, and the filtered water is introduced from the end of the hollow fiber membrane and discharged from the outer peripheral surface thereof. It is a structure that performs filtration by internal pressure filtration.

  The cylindrical molded body is a cylindrical molded body that is intended to be a hollow cylindrical molded body and can move without leakage of substances passing through the cylindrical molded body. The shape of the cylindrical molded body may be circular, polygonal, elliptical, or irregular. In addition, the flow of filtered water that passes through the inside of the cylindrical molded body may be linear, and when a side tube is provided on the wall of the cylindrical molded body, the structure includes a bent portion. The water flow may be non-linear.

  The predetermined distance for specifying the inner diameter B is a predetermined distance along the long axis direction of the hollow fiber membrane from the end face of the sealing portion, and the water to be filtered that has passed through the hollow fiber membrane in the cylindrical molded body Retention is likely to occur when (concentrated water) flows into the closed portion of the cylindrical molded body (for example, the space region on the connection member side or the contact surface side between the sealed portion and the water to be filtered configured by the container). It means depth position.

  In addition, let the end surface of the side which contacts the to-be-filtered water of a sealing part be a starting point, let the side which contacts to to-be-filtered water be + X direction, and let the side through which to-be-filtered water pass pass be -X direction. In addition, the major axis direction of the hollow fiber membrane intends the inner diameter B at a predetermined distance along the + X direction.

  Moreover, as a flow direction selection part which switches the direction which the to-be-filtered water flows in a membrane module between a forward direction and a reverse direction, a valve, a pump, a check valve etc. can be used, for example.

  When the flow direction of the filtered water is switched to the reverse direction by the flow direction selection unit, the water that has passed through the membrane module may be returned to the filtered water tank, or another tank (for example, a raw water tank, You may discharge to a receiving tank, a relay tank, a drainage mass, etc.).

  Here, when the value (A / B) is larger than 2.0, the inner diameter on the outflow side of the water to be filtered becomes extremely thin with respect to the membrane module side container. Become.

  Therefore, if (A / B) is 2.0 or less, the water to be filtered in the membrane module is flowed in both directions by switching from the water tank to be filtered to the forward direction or the reverse direction with respect to the membrane module. In the case where the water to be filtered flows in either the forward direction or the reverse direction, the flow of the water to be filtered can be suppressed in the outflow side portion.

  As a result, it is possible to prevent water from being filtered and to stably perform water treatment.

  The water treatment apparatus according to the second invention is the water treatment apparatus according to the first invention, wherein the predetermined distance is a distance of 0.15 A from the end face of the sealing portion.

  Here, the position of the inner diameter B is specifically defined as a distance of depth 0.15A from the end face of the sealing portion.

  Thus, when the inner diameter at a certain depth position from the end face of the sealing portion is regulated with respect to the diameter of the end face of the sealing portion, the water to be filtered flows in either the forward direction or the reverse direction. However, it can suppress that the flow of to-be-filtered water is prevented in the part of a connection member.

  As a result, it is possible to prevent water from being filtered and to stably perform water treatment.

  A water treatment device according to a third aspect of the present invention is the water treatment device according to the first or second aspect of the present invention, and the cylindrical molded body is an integral molded body or a separate molded body.

  A water treatment apparatus according to a fourth aspect of the present invention is the water treatment apparatus according to the third aspect of the present invention, wherein the cylindrical molded body has any one of the following configurations (P) and (Q): .

(P) When the cylindrical molded body is an integrally molded product, the cylindrical molded body is a container, the sealing portion is fixed to the container, and the inner diameter of the container is B.
(Q) When the cylindrical molded body is a separate molded body, the cylindrical molded body is constituted by the container and the connection member, the sealing portion is fixed to the container, and the inner diameter of the connection member is B.

Here, the container (P) is a molded product that accommodates the hollow fiber membrane.
The connection member (Q) is a molded product that is connected and fixed to the container, and is a molded product that uses one or more of the joints (L-shaped structure, I-shaped structure, T-shaped structure, or cross structure). ), And lids. In addition, when fixing a connection member to a container, adhesion | attachment, fusion | fusion, or a container and a connection member can be connected and fixed mutually by a general method, and a water leak can be prevented.

  The cylindrical molded body preferably has the configuration (Q) from the viewpoints of moldability and assemblability of each molded product, but it is also possible to configure a water treatment apparatus by combining (P) and (Q). .

  Hereinafter, the separate structure (Q) will be described. The connecting member is provided so as to be fitted to both ends of the container holding the membrane module, and when the water to be filtered flows in the forward direction or the reverse direction, it is filtered by the reduced diameter portion of the opening of the connecting member. The range of A / B is defined so as not to hinder the flow of water.

  When the value (A / B) obtained by dividing the diameter of the end face of the sealing portion by the inner diameter on the connecting member side is larger than 2.0, the connecting member that becomes the outflow side of the water to be filtered with respect to the membrane module side container Since the inner diameter of the tube becomes extremely thin, the effluent water is likely to stay.

  Therefore, if (A / B) is 2.0 or less, the water to be filtered in the membrane module is flowed in both directions by switching from the water tank to be filtered to the forward direction or the reverse direction with respect to the membrane module. Even when the water to be filtered flows in either the forward direction or the reverse direction, it is possible to suppress the flow of the water to be filtered in the connecting member portion while preventing the occurrence of clogging.

  As a result, it is possible to prevent water from being filtered and to stably perform water treatment.

  A water treatment apparatus according to a fifth aspect of the present invention is the water treatment apparatus according to any one of the first to fourth aspects of the present invention, wherein the flow direction selector is operated to control the flow direction of the filtered water. The unit is further provided. The control unit controls the flow rate in the membrane so that the following relational expression (4) is satisfied when the flow rate in the forward or reverse direction of the water to be filtered is set to the high flow rate in the membrane and the low flow rate in the membrane. To do.

1 ≦ High flow rate in the membrane / Low flow rate in the membrane ≦ 30 (4)
Here, when the intra-membrane flow velocity in the forward direction or reverse direction of the water to be filtered is set to the high intra-membrane flow velocity and the low intra-membrane flow velocity, the ratio of the two satisfies the relational expression (4).

  Thereby, when flowing the water to be filtered while switching between the forward direction and the reverse direction, the flow rate in one direction in the membrane module can be controlled to be equal to or greater than the flow rate in the other direction.

  As a result, it is possible to ensure the same degree of obstruction suppression effect or obstruction removal effect of the filtered water regardless of the forward direction or the reverse direction. In particular, when the flow is changed, it is possible to further expect a clogging suppression effect or a clogging removal effect of the filtered water.

  A water treatment device according to a sixth aspect of the present invention is the water treatment device according to any one of the first to fifth aspects of the invention, wherein the water tank to be filtered from the filtration tank to the membrane module in both the forward and reverse directions. And a single drive source for supplying filtered water.

  Here, a single drive source is used when sending the water to be filtered from the water tank to be filtered to the membrane module in the forward and reverse directions.

Here, examples of the drive source include a pump, a compressor, and a blower.
This prevents the clogged water from clogging in the membrane module by flowing the filtered water in both directions by switching from the filtered water tank to the forward or reverse direction with respect to the membrane module with a simple configuration. Can do.

  A water treatment device according to a seventh invention is the water treatment device according to any one of the first to sixth inventions, wherein the flow direction selector is a flow in at least one of the first line and the second line. It is a valve that opens and closes the road.

Here, a valve is used as the flow direction selector.
Here, as the valve, for example, various valves such as a three-way valve and a check valve can be used.

  Thereby, the flow direction of the to-be-filtered water with respect to a membrane module can be easily switched using various valves.

  A water treatment apparatus according to an eighth invention is the water treatment apparatus according to any one of the first to seventh inventions, wherein the flow direction selection unit is operated to control the flow direction of the water to be filtered. The unit is further provided. A control part switches the flow direction of to-be-filtered water, and wash | cleans a membrane module.

  Here, the washing | cleaning process which switches the direction through which to-be-filtered water flows and wash | cleans a membrane module is implemented.

  Thereby, the state which flows the to-be-filtered water to a normal direction can be made into a normal driving | running state, and the state to which to-be-filtered water can be flowed to a reverse direction can be made into the state which performs the washing | cleaning process of a membrane module.

  A water treatment apparatus according to a ninth aspect is the water treatment apparatus according to the eighth aspect, wherein the control unit performs back pressure cleaning that applies back pressure from the outer peripheral surface of the hollow fiber membrane.

  Here, as the cleaning step, back pressure cleaning is performed simultaneously, in which back pressure is applied from the outer peripheral surface of the hollow fiber membrane.

  Thereby, washing | cleaning of the membrane module which implements internal pressure type filtration can be effectively implemented by applying a back pressure from the outer peripheral surface of the hollow fiber membrane which comprises a membrane module, and implementing a washing | cleaning process.

  A water treatment device according to a tenth aspect of the invention is the water treatment device according to the eighth or ninth aspect of the invention, further comprising a pressure sensor for detecting the pressure of the water to be filtered supplied to the membrane module. Yes. The control unit is configured to flow the filtered water when the pressure difference detected by the pressure sensor with respect to the initial pressure immediately after switching the flow direction of the filtered water by the flow direction selecting unit fluctuates by ± 15% or more. The flow direction selector is controlled so as to switch between the two.

  Here, when the pressure detection result of the pressure sensor that detects the pressure of the water to be filtered supplied to the membrane module becomes a differential pressure of ± 15% or more with respect to the initial value immediately after switching the flow direction, the blockage ( It is determined that clogging) has occurred or the blockage (clogging) has been resolved, and the flow direction of filtered water is switched.

  Thereby, when performing constant flow control, the cleaning process can be performed at an appropriate timing by estimating the occurrence of clogging (clogging) in the membrane module using the detection result of the pressure sensor.

  A water treatment device according to an eleventh aspect of the invention is the water treatment device according to the eighth or ninth aspect of the invention, further comprising a flow sensor that detects the flow rate of the water to be filtered in the membrane module. When the pressure difference of the detection result in the flow sensor with respect to the detection result in the flow sensor immediately after switching the flow direction of the filtered water by the flow direction selection unit fluctuates by ± 15% or more, the filtered water flows. The flow direction selector is controlled to switch the direction.

  Here, when the flow rate detection result of the flow rate sensor that detects the flow rate of water to be filtered in the membrane module becomes a differential pressure of ± 15% or more with respect to the initial value immediately after switching the flow direction, clogging (clogging) occurs. Judge that the occurrence or blockage (clogging) has been resolved, and switch the flow direction of filtered water.

  Accordingly, when the constant pressure control is performed, the cleaning process can be performed at an appropriate timing by estimating the occurrence of clogging (clogging) in the membrane module using the detection result of the flow sensor.

  A water treatment method according to a twelfth invention is the water treatment method in the water treatment device according to any one of the first to eleventh inventions.

  Here, the invention is realized as a water treatment method in a water treatment apparatus having the above-described configuration.

  Thus, for example, when a predetermined time elapses or when a blockage (clogging) of the membrane module is detected using a pressure sensor or the like, filtration can be performed while switching the direction in which the water to be filtered flows.

  As a result, it is possible to prevent water from being filtered and to stably perform water treatment.

  According to the water treatment device of the present invention, it is possible to stably perform water treatment by preventing the filtered water from being blocked.

The system diagram which shows the structure of the water treatment apparatus which concerns on one Embodiment of this invention. (A) is a figure which shows the state at the time of flowing to-be-filtered water in the forward direction in the water treatment apparatus of FIG. (B) is a figure which shows the state at the time of flowing the to-be-filtered water in the reverse direction in the water treatment apparatus of FIG. The front view which shows the structure of the membrane module contained in the water treatment apparatus of FIG. Sectional drawing of the membrane module of FIG. The side view which looked at the container which comprises the membrane module of FIG. 3 from the opening end side. FIG. 4 is a side sectional view of a connection member that constitutes the membrane module of FIG. 3. (A)-(c) is a figure which shows the magnitude relationship of the diameter A of the edge part of a sealing part, and the internal diameter B of a connection member. The flowchart which shows the flow of the water treatment method in the water treatment apparatus of FIG. The figure explaining the conditions for a control part to change a flow direction in the water treatment apparatus of FIG. The figure explaining the conditions for a control part to change a flow direction in the water treatment apparatus of FIG. (A) is a system diagram which shows the structure of the water treatment apparatus which concerns on other embodiment of this invention. (B) is a figure which shows the state at the time of flowing water to be filtered in the forward direction in the water treatment apparatus of (a). (C) is a figure which shows the state at the time of flowing the to-be-filtered water in the reverse direction in the water treatment apparatus of (a). Sectional drawing which shows the structure of the membrane module contained in the water treatment apparatus which concerns on further another embodiment of this invention. Sectional drawing which shows the structure of the membrane module contained in the water treatment apparatus which concerns on further another embodiment of this invention. Sectional drawing which shows the structure of the membrane module contained in the water treatment apparatus which concerns on further another embodiment of this invention. The figure which compared the result of the membrane filtration stability test in Examples 1-6 of this invention and Comparative Examples 1-4.

(Embodiment 1)
It will be as follows if the water treatment apparatus which concerns on one Embodiment of this invention is demonstrated using FIGS. In addition, in description of FIGS. 1-10, (Q) Embodiment in case a cylindrical molded object is a separate molded object is described.

(Configuration of water treatment device 10)
A water treatment device 10 according to this embodiment is a device that performs water treatment for purifying water to be filtered by internal pressure filtration, and includes a water tank 11 to be filtered and a pump (drive source) 12 as shown in FIG. A pump (drive source) 13, a check valve (flow direction selection unit) 14, a check valve (flow direction selection unit) 15, a valve (flow direction selection unit) 16, and a valve (flow direction selection unit). ) 17, the membrane module 20, the control unit 30, the first lines 31a and 32a, the second lines 31b and 32b, and the pressure sensors 33a and 33b.

  As shown in FIG. 1, the to-be-filtered water tank 11 is a water tank that stores the to-be-filtered water W, and is connected to the first lines 31a and 32a and the second lines 31b and 32b.

  As shown in FIG. 1, the first pump (drive source) 12 is provided in the first line 31a. The first pump 12 supplies the filtered water W to the membrane module 20 along the forward direction via the first line 31a, and the concentrated water that has passed through the membrane module 20 is supplied to the second line 31b. Then, it is returned to the filtered water tank 11 again.

  The 2nd pump (drive source) 13 is provided in the 1st line 32a, as shown in FIG. And while the 2nd pump 13 supplies the to-be-filtered water W to the membrane module 20 along the reverse direction via the 1st line 32a, the 2nd line 32b is used for the concentrated water which passed the membrane module 20. Then, it is returned to the filtered water tank 11 again.

  As shown in FIG. 1, the check valve (flow direction selector) 14 is provided in the first line 31 a and allows the water to be filtered W to pass only in the direction of the arrow in the figure.

  As shown in FIG. 1, the check valve (flow direction selector) 15 is provided in the first line 32 a and allows the water to be filtered W to pass only in the direction of the arrow in the figure.

  As shown in FIG. 1, the valve (flow direction selection unit) 16 is provided in the second line 31 b and is controlled to be opened and closed by the control unit 30. Thereby, the valve | bulb 16 functions as a means to select the direction through which the to-be-filtered water W flows.

  As shown in FIG. 1, the valve (flow direction selection unit) 17 is provided in the second line 32 b and is controlled to be opened and closed by the control unit 30. Thereby, the valve | bulb 17 functions as a means to select the direction through which the to-be-filtered water W flows.

  In the water treatment apparatus 10 of the present embodiment, the flow direction of the filtered water W with respect to the membrane module 20 is selectively switched by the check valves 14 and 15 and the valves 16 and 17 as described above.

  As shown in FIG. 1, the membrane module 20 is connected to the water tank 11 to be filtered through the first lines 31a and 32a and the second lines 31b and 32b. And the membrane module 20 implements the water treatment which refine | purifies filtered water from the supplied to-be-filtered water W by internal pressure type filtration. The configuration of the membrane module 20 will be described in detail later.

  As shown in FIG. 1, the controller 30 is connected to the first and second pumps 12 and 13, the valves 16 and 17, and the pressure sensors 33 a and 33 b, and controls them according to various setting conditions.

  Specifically, when the filtered water W in the filtered water tank 11 is supplied to the membrane module 20 along the forward direction, the control unit 30 is configured as shown in FIG. 1 pump 12 is driven, and to-be-filtered water W is supplied to the membrane module 20 via the check valve 14 via the first line 31a. And the concentrated water which passed the membrane module 20 is returned to the to-be-filtered water tank 11 again via the valve | bulb 16 of an open state via the 2nd line 31b.

  That is, when supplying the filtered water W to the membrane module 20 along the forward direction, the control unit 30 controls the first pump 12 to be driven and the valve 16 to be opened.

  On the other hand, when supplying the filtered water W in the filtered water tank 11 to the membrane module 20 along the reverse direction, the control unit 30, as shown in FIG. To be filtered and the filtered water W is supplied to the membrane module 20 via the check valve 15 via the first line 32a. And the concentrated water which passed the membrane module 20 is returned to the to-be-filtered water tank 11 again via the valve | bulb 17 of an open state via the 2nd line 32b.

  That is, when supplying the filtered water W to the membrane module 20 along the reverse direction, the control unit 30 controls the second pump 13 to be driven and the valve 17 to be opened.

The water treatment method by the control unit 30 will be described in detail later.
As shown in FIG. 1, the first lines 31 a and 32 a are lines for supplying the filtered water W from the filtered water tank 11 to the membrane module 20, and are the first and second pumps 12 and 13 and the check. Valves 14 and 15 are provided.

  As shown in FIG. 1, the second lines 31 b and 32 b are lines for returning the concentrated water that has passed through the membrane module 20 to the filtered water tank 11, and are provided with valves 16 and 17.

  In addition, the 2nd line 31b is connected to the to-be-filtered water tank 11, and returns the concentrated water which passed the membrane module 20. On the other hand, the 2nd line 32b is connected in the water of the to-be-filtered water tank 11, and returns the concentrated water which passed the membrane module 20.

  As shown in FIG. 1, the pressure sensors 33 a and 33 b are provided in the first lines 31 a and 32 a, respectively, and the pressure of the filtered water W supplied to the membrane module 20 through the first lines 31 a and 32 a. To detect.

(Membrane module 20)
As shown in FIG. 3, the membrane module 20 includes a main body portion 21 and connecting members 22 and 23 attached to both ends of the main body portion 21.

  As shown in FIG. 3, the main body 21 is configured by a cylindrical container (cylindrical molded body) 21 a, and as shown in FIG. 4, a plurality of tubular shapes are provided in the internal space of the cylindrical container 21 a. A hollow fiber membrane 21b in which these members are bundled together and sealing portions 21c and 21c are provided.

  The hollow fiber membrane 21b is configured by a bundle of a plurality of tube-shaped members. When the water to be filtered W supplied into the tube from the first end side is supplied with pressure, the hollow fiber membrane 21b bleeds from the outer peripheral surface. The filtered water that comes out can be obtained. And the concentrated water except filtered water is discharged | emitted from the 2nd end side on the opposite side to the 1st end of a tube.

  Moreover, as shown in FIG. 4, the hollow fiber membrane 21b is being fixed by the sealing parts 21c and 21c in the both ends of the container 21a in the state which bundled the tube-shaped member.

  The first pump 12 or the second pump 13 is preferably driven and controlled so that the flow rate of the water to be filtered W flowing inside the hollow fiber membrane 21b is 0.05 m / s or more. The flow rate is more preferably set in the range of 0.1 m / s to 1.5 m / s.

  Further, the inner diameter of the hollow fiber membrane 21b is preferably 0.05 mm or more, and more preferably 1 mm or more. Furthermore, the inner diameter of the hollow fiber membrane 21b is more preferably in the range of 1 mm to 10 mm.

  Further, the turbidity or SS concentration applicable to the hollow fiber membrane 21b is not limited, but is preferably 50 degrees or 50 mg / L or more, more effectively 100 degrees or 100 mg / L or more, and further effects. Specifically, 200 degrees or 200 mg / L or more is preferable.

  Control is performed so that the following relational expression (4) is satisfied when the in-membrane flow velocity in both the forward direction and the reverse direction of the water W to be filtered in the hollow fiber membrane 21b is set to a high in-membrane flow velocity and a low in-membrane flow velocity. The first pump 12 and the second pump 13 are controlled by the unit 30.

1 ≦ High flow rate in the membrane / Low flow rate in the membrane ≦ 30 (4)
Thereby, when flowing the water to be filtered W while switching between the forward direction and the reverse direction, the flow rate in one direction in the membrane module 20 can be controlled to be equal to or greater than the flow rate in the other direction. .

  As a result, it is easy to peel off the dirt stuck in the hollow fiber membrane 21b by flowing the flow velocity high and low in the forward direction and the reverse direction so as to be equal or larger. As a result, it is possible to suppress the occurrence of clogging in the hollow fiber membrane 21b and perform a good water treatment operation.

  As shown in FIG. 4, the sealing portions 21c and 21c are provided at both end portions of the container 21a. The sealing portions 21c and 21c fix both ends of the hollow fiber membrane 21b to the inner wall surface of the container 21a, and connect the hollow fiber membrane 21b and the container 21a, or the hollow fiber membranes 21b to each other at both ends of the container 21a. Seal.

  The sealing portions 21c and 21c fix the both ends of the hollow fiber membrane 21b to both ends of the container 21a and seal the hollow fiber membrane 21b and the container 21a or the hollow fiber membranes 21b at both ends of the container 21a. An adhesive can be used. Moreover, as sealing parts 21c and 21c, you may use other sealing members, such as an O-ring other than an adhesive agent, for example.

  Here, the sealing portions 21c and 21c have a diameter A that is the same size as the diameter of the container 21a.

  The connection member 22 has an inflow port 24a into which the water to be filtered W flows when the water to be filtered W is supplied in the forward direction. In addition, when the to-be-filtered water W is supplied in the reverse direction, the inflow port 24a functions as an outflow port, and the outflow port 24c functions as an inflow port.

  In the present embodiment, the inflow port 24a and the outflow port 24c are provided on the connection member 22 along the moving direction of the water to be filtered in the membrane module 20, respectively. Surface).

  Further, when reverse cleaning described later is performed, the outlet 24b through which filtrate flows out functions as an inlet.

  Here, as shown in FIG. 6, the openings connected to both ends of the container 21a in the connecting members 22 and 23 have a predetermined distance in the depth direction (long axis direction of the hollow fiber membrane 21b; + X direction), specifically Has an inner diameter B at a position of 0.15A.

  In the water treatment apparatus 10 of the present embodiment, when the diameter A of the end surfaces of the sealing portions 21c and 21c and the inner diameter B at a predetermined distance in the depth direction of the opening on the connection members 22 and 23 side, the following relational expression is obtained. It is configured to meet.

A / B ≦ 2.0 (1)
Thereby, as shown to Fig.7 (a), the to-be-filtered water W in the membrane module 20 is flowed with respect to the membrane module 20 from the to-be-filtered water tank 11 in the forward direction and the reverse direction. Even if the water to be filtered W flows in either the forward direction or the reverse direction, the flow of the water to be filtered W is prevented from being disturbed at the connection members 22 and 23. Can do.

  As a result, it is possible to prevent the clogged water to be filtered W from occurring in the membrane module 20 and stably perform water treatment.

Moreover, it is more preferable that A / B satisfies the following relational expression (2).
0.5 ≦ A / B ≦ 2.0 (2)
Thereby, as shown in FIG.7 (c), the diameter A of the end surface of the sealing parts 21c and 21c by the side of the container 21a of the membrane module 20 is made into the connection by setting the lower limit of A / B to 0.5. The range may be larger than the state slightly smaller than the inner diameter B on the members 22 and 23 side.

  Therefore, the water to be filtered W (concentrated water) passing through the membrane module 20 is prevented from flowing due to the reduced diameter portions of the inner diameters of the connecting members 22 and 23 and staying therein, thereby preventing the filtered water W from being blocked. Water treatment can be carried out stably.

Furthermore, it is more preferable that A / B satisfies the following relational expression (3).
0.8 ≦ A / B ≦ 2.0 (3)
As a result, as shown in FIG. 7B, by setting the lower limit value of A / B to 0.8, the diameter A of the end faces of the sealing portions 21c, 21c of the membrane module 20 is changed to the connecting members 22, 23. The range may be larger than the state slightly smaller than the inner diameter B on the side.

  As a result, the to-be-filtered water exiting from the membrane module 20 is prevented from staying because the flow is hindered by the reduced diameter portions of the connecting members 22 and 23, and the filtered water W is prevented from being blocked. Water treatment can be carried out.

As described above, A / B is preferably 2.0 or less.
For example, when the diameter A of the end surfaces of the sealing portions 21c and 21c is larger than 2.0 with respect to the inner diameter B on the connection members 22 and 23 side, the side of the filtered water W in contact with the end surfaces of the sealing portions 21c and 21c. When flowing in the direction toward the connecting members 22 and 23 (inner diameter B), the outlet of the water to be filtered W becomes narrow, and there is a possibility that water may stay in a narrow region. For this reason, it is more preferable that A / B is set within a range of 0.8 ≦ A / B ≦ 2.0.

  Further, if the diameter A of the end faces of the sealing portions 21c and 21c and the inner diameter B on the connecting members 22 and 23 side are equal or larger, the diameter of the end faces of the sealing portions 21c and 21c is reduced. When flowing from the side in contact with A in the direction of the connecting members 22 and 23 (inner diameter B), water is less likely to stay. For this reason, it is particularly preferable that A / B is set in a range of 0.8 ≦ A / B ≦ 2.0.

  Moreover, in the water treatment apparatus 10 of this embodiment, the control part 30 makes the one where a flow velocity is larger among the membrane flow velocity in the bidirectional | two-way of the forward direction and the reverse direction of the to-be-filtered water W in the membrane flow velocity high and small one. When the intra-membrane flow rate is low, the intra-membrane flow rate is controlled so as to satisfy the following relational expression (4).

1 ≦ High flow rate in the membrane / Low flow rate in the membrane ≦ 30 (4)
Thereby, when flowing the water to be filtered W while switching between the forward direction and the reverse direction, the flow rate in one direction in the membrane module 20 can be controlled to be equal to or greater than the flow rate in the other direction. .

  As a result, it is easy to peel off the dirt stuck in the hollow fiber membrane 21b by flowing the flow velocity high and low in the forward direction and the reverse direction so as to be equal or larger. As a result, it is possible to suppress the occurrence of clogging in the hollow fiber membrane 21b and perform a good water treatment operation.

<Water treatment method>
In the water treatment apparatus 10 of this embodiment, the water treatment which refine | purifies filtrate water from the to-be-filtered water W is performed according to the flowchart shown in FIG.

  That is, in step S11, the 1st pump 12 is operated and the to-be-filtered water W is sent to the membrane module 20 from the to-be-filtered water tank 11 to a forward direction (1st process).

  More specifically, as shown in FIG. 2 (a), the first pump 12 sends filtered water W from the filtered water tank 11, and passes through the check valve 14 to the inlet 24 a of the membrane module 20. Thus, the water to be filtered W is supplied in the forward direction. And the concentrated water which passed the membrane module 20 is returned to the to-be-filtered water tank 11 via the valve | bulb 16 via the 2nd line 31b.

  Next, in step S12, in the membrane module 20, the to-be-filtered water W is purified by internal pressure filtration using the hollow fiber membrane 21b, and the filtrate is purified.

  At this time, as shown in FIGS. 3 and 4, the membrane module 20 is supplied with filtered water W from the inflow port 24a, sent filtered water from the outflow port 24b, and concentrated water from the outflow port 24c. Sent out.

  Next, in step S13, it is determined whether or not a predetermined time has passed, or whether or not it has fluctuated by ± 15% or more immediately after switching the direction in which the pressure of the filtered water W supplied to the membrane module 20 flows.

  The pressure fluctuation is detected using pressure sensors 33a and 33b provided on the first lines 31a and 32a.

  Here, if any one of the above conditions is satisfied, the process proceeds to step S14. If the above condition is not satisfied, step S13 is repeated until the above condition is satisfied.

  Next, in step S14, since the occurrence of clogging in the membrane module 20 is estimated, the direction of the filtered water W flowing in the membrane module 20 is switched from the forward direction to the reverse direction (second step).

  Specifically, the control unit 30 switches the driving of the first pump 12 from the driving state of the first pump 12 and the valve 16 so that the driving of the first pump 12 is stopped and the valve 16 is closed. Further, the control unit 30 drives the second pump 13 and switches the valve 17 from the closed state to the open state, thereby switching the direction of the filtered water W flowing through the membrane module 20 from the forward direction to the reverse direction.

  Next, in step S15, the to-be-filtered water W is poured in the reverse direction with respect to the membrane module 20 in step S14.

  More specifically, as shown in FIG. 2 (b), filtered water W is sent out from the filtered water tank 11 through the first line 32 a by the second pump 13, and the membrane module is connected through the check valve 15. The filtered water W is supplied to the twenty outlets 24c. And the concentrated water which passed the membrane module 20 is returned to the to-be-filtered water tank 11 via the valve | bulb 17 via the 2nd line 32b.

  Thereby, to-be-filtered water W is supplied to the membrane module 20 from the reverse direction opposite to a forward direction, and the reverse washing process which eliminates obstruction | occlusion of the to-be-filtered water W in the end surface of the hollow fiber membrane 21b is implemented. Can do.

  In addition, in the flowchart shown in FIG. 8, although the flow at the time of sending out filtered water to a forward direction and switching to a reverse direction was demonstrated, also about the flow at the time of sending filtered water to a reverse direction and switching to a forward direction It is the same.

  Here, when the in-membrane flow velocity in the forward direction and the reverse direction of the water to be filtered W in the hollow fiber membrane 21b is set to the high in-membrane flow velocity and the low in-membrane flow velocity, the following relational expression (4) is satisfied. In addition, the first pump 12 and the second pump 13 are controlled by the control unit 30.

1 ≦ High flow rate in the membrane / Low flow rate in the membrane ≦ 30 (4)
Thereby, when flowing the water to be filtered W while switching between the forward direction and the reverse direction, the flow rate in one direction in the membrane module 20 can be controlled to be equal to or greater than the flow rate in the other direction. .

  As a result, it is easy to peel off the dirt stuck in the hollow fiber membrane 21b by flowing the flow velocity high and low in the forward direction and the reverse direction so as to be equal or larger. As a result, it is possible to suppress the occurrence of clogging in the hollow fiber membrane 21b and perform a good water treatment operation.

  Further, in conjunction with the reverse cleaning process of the end face portion of the membrane module 20, a counter pressure is applied from the secondary side of the hollow fiber membrane 21b (perpendicular to the length direction of the hollow fiber membrane 21b), as described above. The water to be filtered W may be introduced into the outlet 24b of the container 21a to perform back pressure cleaning.

  In this case, since the pressure can be applied from the outer peripheral surface of the hollow fiber membrane 21b by the water to be filtered W, the membrane module 20 can be effectively removed by eliminating the clogging (clogging) of the membrane of the hollow fiber membrane 21b. Can be washed. In addition, control which switches the direction which flows the to-be-filtered water W from a forward direction to a reverse direction is implemented based on the conditions shown in FIG. 9 and FIG.

  In FIG. 9, the detection result in the pressure sensor 33a provided in the first line 31a and the in-membrane flow rate converted from the detection result in the flow rate sensor (not shown) are started from the filtration elapsed time 0 minutes, It shows how it changes over time. Specifically, at the filtration elapsed time of 0 minutes, the detection result of the pressure sensor 33a was 0.100 MPa, and the in-membrane flow rate was 0.2 m / s. In the example shown in FIG. 9, the intra-membrane flow rate was constant at 0.2 m / s even after the elapsed time of filtration.

  That is, in the example shown in FIG. 9, the control of switching the direction in which the water to be filtered W is flowed is performed by monitoring the fluctuation of the pressure of the water W to be filtered supplied to the membrane module 20.

  Here, when the filtration elapsed time passes 20 minutes, 40 minutes, 60 minutes, and 120 minutes, the detection result in the pressure sensor 33a increases to 0.102 MPa, 0.105 MPa, 0.108 MPa, and 0.130 MPa. Go.

  At this time, the pressure 0.130 MPa at the time of filtration elapsed time 120 minutes is 30.0% of the pressure 0.100 MPa at the time of filtration elapsed time 0 minutes.

  Since this differential pressure exceeds the above-described fluctuation range of ± 15%, the control unit 30 changes the direction in which the filtered water W flows to the membrane module 20 from the forward direction (low to high) to the reverse direction ( Switch from high to low).

  And after switching the direction through which the to-be-filtered water W flows at the time of filtration elapsed time 120 minutes, when the filtration elapsed time 150 minutes passes, the detection result in the pressure sensor 33b will fall to 0.110 MPa.

  At this time, the pressure 0.110 MPa at the time of filtration elapsed time 150 minutes is -15.4% of the pressure 0.130 MPa at the time of filtration elapsed time 120 minutes.

  Again, since this differential pressure exceeds the above-described fluctuation range of ± 15%, the control unit 30 changes the direction in which the water to be filtered W flows to the membrane module 20 from the reverse direction (high to low). Switch forward (low to high).

  Then, when the filtration elapsed time has passed 180 minutes, the control unit 30 determines that the predetermined time set in advance has passed, and allows the water to be filtered W to flow from the outlet 24b so that the membrane of the hollow fiber membrane 21b is Perform reverse cleaning to eliminate clogging.

  After performing reverse cleaning, the control unit 30 resets the filtration elapsed time and performs the water treatment described above again.

  Next, FIG. 10 shows a state in which the in-membrane flow rate converted from the detection result in the flow rate sensor (not shown) starts with the elapsed time of filtration 0 minutes and changes with time.

  That is, in the example shown in FIG. 10, the control of switching the flow direction of the water W to be filtered is performed by monitoring the fluctuation of the in-membrane flow velocity of the membrane module 20.

  Specifically, the detected intra-membrane flow rate was 0.150 m / s at the filtration elapsed time of 0 minutes.

  That is, in the example shown in FIG. 10, the control of switching the flow direction of the water to be filtered W is performed by monitoring the fluctuation of the in-membrane flow velocity in the membrane module 20.

  Here, when the elapsed filtration time is 20 minutes, 40 minutes, 60 minutes, and 120 minutes, the in-membrane flow rates are 0.145 m / s, 0.140 m / s, 0.135 m / s, and 0.125 m / s. It goes down with s.

  At this time, the in-membrane flow rate 0.125 m / s at the time of filtration elapsed time 120 minutes is 16.7% of the differential pressure with respect to the in-membrane flow rate 0.150 m / s at the time of filtration elapsed time 0 minutes. Become.

  Since this differential pressure exceeds the above-described fluctuation range of ± 15%, the control unit 30 changes the direction in which the filtered water W flows to the membrane module 20 from the forward direction (low to high) to the reverse direction ( Switch from high to low).

  And after switching the direction which flows the to-be-filtered water W in the time of filtration elapsed time 120 minutes, if the filtration elapsed time 150 minutes passes, the in-membrane flow velocity will rise to 0.145.

  At this time, the in-membrane flow rate 0.145 m / s at the filtration elapsed time 150 minutes is 16.0% of the differential pressure with respect to the intra-membrane flow rate 0.125 m / s at the filtration elapsed time 120 minutes. Become.

  Again, since this differential pressure exceeds the above-described fluctuation range of ± 15%, the control unit 30 changes the direction in which the water to be filtered W flows to the membrane module 20 from the reverse direction (high to low). Switch forward (low to high).

  Then, when the filtration elapsed time has passed 180 minutes, the control unit 30 determines that the predetermined time set in advance has passed, and allows the water to be filtered W to flow from the outlet 24b so that the membrane of the hollow fiber membrane 21b is Perform reverse cleaning to eliminate clogging.

  After performing reverse cleaning, the control unit 30 resets the filtration elapsed time and performs the water treatment described above again.

(Embodiment 2)
It will be as follows if the water treatment apparatus which concerns on other embodiment of this invention is demonstrated using Fig.11 (a)-FIG.11 (c).

  Here, as shown in FIG. 11A, the water treatment apparatus 410 of this embodiment performs water treatment while switching the flow direction using a single drive source (pump 412) and valves 416, 417, and 418. Do. Furthermore, in the water treatment apparatus 410 of this embodiment, the flow rate supplied to the membrane module 420 is assisted using the blower 413.

  That is, the water treatment apparatus 410 includes the water tank 11 to be filtered, the pump 412, the blower 413, the valves 416, 417, 418, and 419, and the membrane module 420 as shown in FIG. .

  The pump 412 is provided in the first line 431 a and functions as a drive source when the filtered water W flows in the forward direction and the reverse direction with respect to the membrane module 420.

  The blower 413 is provided in the first line 431a, and functions as a drive source that assists the flow rate of the filtered water W when the filtered water W flows in the forward direction with respect to the membrane module 420.

  The valve 416 is provided in the second line 431b, and is opened when the filtered water W is supplied in the forward direction to the membrane module 420, and closed when the filtered water W is supplied in the reverse direction. State.

  The valve 417 is provided in the second line 432b, and is opened when the filtered water W is supplied in the reverse direction to the membrane module 420, and closed when the filtered water W is supplied in the forward direction. State.

  The valve 418 is provided in the first line 431a, and is opened when the filtered water W is supplied to the membrane module 420 in the forward direction, and closed when the filtered water W is supplied in the reverse direction. State.

  The valve 419 is provided in the first line 432a, and is opened when the filtered water W is supplied to the membrane module 420 in the reverse direction, and closed when the filtered water W is supplied in the forward direction. State.

  Although not shown in the present embodiment, the opening / closing of the valves 416 to 419 is controlled by the control unit as in the first embodiment.

The membrane module 420 has the same configuration as that of the first embodiment.
In the water treatment apparatus 410 of the present embodiment, a control unit (not shown) is connected to the pump 412, valves 416, 417, 418, 419 and pressure sensors (not shown), and according to various setting conditions. Control these.

  Specifically, when supplying the water to be filtered W in the water tank 11 to be filtered to the membrane module 420 along the forward direction, the control unit, as shown in FIG. Is driven to supply filtered water W to the membrane module 420 via the first line 431a. Then, the concentrated water that has passed through the membrane module 420 is returned again to the filtered water tank 11 via the second line 431b and the valve 416 in the open state.

  That is, when supplying the filtered water W to the membrane module 420 along the forward direction, the control unit controls the pump 412 as a drive source and the valves 416 and 418 to be in an open state.

  On the other hand, when supplying the filtered water W in the filtered water tank 11 to the membrane module 420 along the reverse direction, the control unit drives the pump 412 as shown in FIG. The filtered water W is supplied to the membrane module 420 via the first line 432a and the valve 419. And the concentrated water which passed the membrane module 420 is returned to the to-be-filtered water tank 11 via the valve | bulb 417 of an open state via the 2nd line 432b.

  That is, when supplying the filtered water W along the reverse direction to the membrane module 420, the control unit drives the pump 412 to open the valves 417 and 419 and close the valves 416 and 418. Control to do.

  In the water treatment apparatus 410 of the present embodiment, as shown in FIGS. 11A to 11C, when the filtered water W is supplied to the membrane module 420 in both the forward and reverse directions, A pump 412 that is a single drive source is used.

Furthermore, in this embodiment, the blower 413 is used to assist the flow rate of the water to be filtered W to the membrane module 420 in the forward direction.
Even with such a configuration, the same effects as those of the first embodiment can be obtained.

[Other Embodiments]
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.

(A)
In the said embodiment, the example which delivers the to-be-filtered water W with respect to the membrane module 120 using two drive sources (1st, 2nd pumps 12 and 13) was demonstrated and demonstrated. However, the present invention is not limited to this.

For example, at least one of the two driving sources may be replaced with an air source (compressor, blower, etc.) from the pump.
Even with such a configuration, the same effects as those of the first embodiment can be obtained.

(B)
In the said embodiment, the concentrated water which passed the membrane module 220 was given and demonstrated to the example returned to the to-be-filtered water tank 11. However, the present invention is not limited to this.

For example, the concentrated water that has passed through the membrane module may be discharged to another tank (such as a relay tank or a drainage mass).
Even with such a configuration, the same effects as those of the first embodiment can be obtained.

(C)
In the said embodiment, the example using the check valves 14 and 15 and the valves 16 and 17 etc. was mentioned and demonstrated as a flow direction selection part. However, the present invention is not limited to this.

For example, a three-way valve may be used as the flow direction selection unit.
Even in such a configuration, the same effect as in the first embodiment can be obtained by switching the opening and closing of the three-way valve.

(D)
In the said embodiment, the example which delivers the to-be-filtered water W with respect to the membrane module 120 using two drive sources (1st, 2nd pumps 12 and 13) was demonstrated and demonstrated. However, the present invention is not limited to this.

For example, a compressor, a blower, or the like may be used as a single drive source.
Even with such a configuration, the same effects as those of the first embodiment can be obtained.

(E)
In the above embodiment, as the position of the inner diameter B on the connection members 22 and 23 side, the inner diameter of the connection members 22 and 23 at a position (depth) of 0.15 A from the end on the connection side of the connection members 22 and 23 is used. The example used is explained. However, the present invention is not limited to this.

  For example, the position of the inner diameter B is not limited to the position having a depth of 0.15A, but may be an inner diameter at a certain depth position from the ends of the connection members 22 and 23.

  Even in this case, the same effect as that of the above embodiment can be obtained by specifying the inner diameter B at the position on the side of the connecting members 22 and 23 where concentrated water (filtered water) that has passed through the hollow fiber membrane 21b easily collides. Can do.

(F)
In the said embodiment, the control part 30 switched and opened and closed the valves 16 and 17, and demonstrated and demonstrated the example which selects the direction through which the to-be-filtered water W flows. However, the present invention is not limited to this.

  For example, the configuration is such that the flow direction of water to be filtered is selected by manually switching the opening and closing of the valve every time a predetermined time elapses or when a predetermined condition is satisfied while monitoring the detection result of the pressure sensor. May be.

(G)
In the above embodiment, when (P) the cylindrical molded body is an integrally molded product, the end surface of the container (cylindrical molded body) 21a and the end surface of the hollow fiber membrane 21b constituting the membrane module 20 are substantially in the axial direction. An example where they are arranged at the same position has been described. However, the present invention is not limited to this.

  For example, as shown in FIG. 12, the end surface of the hollow fiber membrane 121b is disposed on the back side of the container 121a with respect to the end surface of the container 121a, and a space is provided between the hollow fiber membrane 121b and the connecting member 123. It may be.

  In this case, what is necessary is just to set the internal diameter B of the cylindrical molded object in the position of predetermined distance from the sealing part 121c.

Moreover, the structure containing the water collection pipe arrange | positioned along the center axis | shaft of a container may be sufficient.
In this case, the filtered water filtered by the membrane module can be collected by a water collecting pipe arranged along the central axis of the container.

(H)
In the above-described embodiment, the configuration in which the connection members 22 and 23 are connected to both ends of the container 21a in the case where the (Q) cylindrical molded body is a separate molded product has been described as an example. However, the present invention is not limited to this.

  For example, as shown in FIG. 13, a configuration in which cylindrical bodies (connecting members) 222 and 223 are respectively connected to both ends of a container 221 a in which a hollow fiber membrane 221 b is disposed.

  In this case, the inner diameters of the cylinders 222 and 223 at a predetermined distance from the sealing portions 221c and 221c may be B.

Furthermore, for example, as shown in FIG. 14, both end portions of the plurality of membrane modules 320 may be connected to substantially T-shaped portions of the header tubes (connection members) 322 and 323.
In this case, the inner diameter of the header tubes 322 and 323 at a predetermined distance from the sealing portion 321c of the membrane module 320 may be set to B.

<Appendix>
The twelfth invention can also be expressed as a water treatment method using a water treatment device as follows.

A water treatment method in the water treatment apparatus,
A first step of supplying the flow direction of the filtered water in the axial direction in the membrane module in the forward direction;
A second step of switching the flow direction of the water to be filtered by the flow direction selector and supplying the water to be filtered in the reverse direction to the membrane module;
A water treatment method comprising:

A water treatment method according to a thirteenth invention is the water treatment method according to the twelfth invention,
A reverse cleaning process is further provided for cleaning the membrane module by switching the flow direction of the water to be filtered.

  Here, a reverse cleaning process for cleaning the membrane module is performed by switching the flow direction of the water to be filtered.

  Thereby, for example, the state in which the water to be filtered flows in the forward direction can be set as the normal operation state, and the state in which the water to be filtered flows in the reverse direction can be the state in which the reverse cleaning process of the membrane module is performed.

A water treatment device according to a fourteenth invention is a water treatment method according to the thirteenth invention,
In the reverse cleaning step, reverse pressure cleaning is also performed at the same time by applying a reverse pressure from the outer peripheral surface of the hollow fiber membrane.

  Thereby, washing | cleaning of the membrane module which implements internal pressure type filtration can be effectively implemented by applying a back pressure from the outer peripheral surface of the hollow fiber membrane which comprises a membrane module, and implementing a washing | cleaning process.

A water treatment device according to a fifteenth aspect of the present invention is the water treatment method according to the thirteenth or fourteenth aspect of the present invention,
When the pressure difference detected by the pressure sensor with respect to the initial pressure immediately after switching the flow direction of the filtered water fluctuates by ± 15% or more, the flow direction of the filtered water is switched.

  Here, if the pressure detection result of the pressure sensor for detecting the pressure of the water to be filtered supplied to the membrane module becomes a differential pressure of ± 15% or more, it is determined that clogging has occurred, and the water to be filtered Switch the direction of flow.

  Thereby, it is possible to carry out the cleaning process at an appropriate timing by estimating the occurrence of clogging (clogging) in the membrane module using the detection result of the pressure sensor.

A water treatment device according to a sixteenth invention is a water treatment method according to the fifteenth invention,
A differential pressure of at least one of a flow rate of water to be filtered supplied to the membrane module and an intra-membrane flow rate in the membrane module is detected.

  Here, the flow rate of water to be filtered supplied to the membrane module by the flow rate sensor or the in-membrane flow rate (flow rate) in the membrane module is used.

  Thereby, generation | occurrence | production of the obstruction | occlusion (clogging) of a membrane module can be effectively prevented by detecting the flow volume of the to-be-filtered water supplied to a membrane module with a flow sensor.

A water treatment device according to a seventeenth invention is a water treatment method according to any one of the twelfth to fifteenth inventions,
When the intra-membrane flow velocity in the forward direction or reverse direction of the water to be filtered is set to the high intra-membrane flow velocity and the low intra-membrane flow velocity, the intra-membrane flow velocity is controlled so as to satisfy the following relational expression (4).

1 ≦ High flow rate in the membrane / Low flow rate in the membrane ≦ 30 (4)
Here, when the intra-membrane flow velocity in the forward direction or reverse direction of the water to be filtered is set to the high intra-membrane flow velocity and the low intra-membrane flow velocity, the ratio of the two satisfies the relational expression (4).

  Thereby, when flowing the water to be filtered while switching between the forward direction and the reverse direction, the flow rate in one direction in the membrane module can be controlled to be equal to or greater than the flow rate in the other direction.

  As a result, it is possible to ensure the same degree of obstruction suppression effect or obstruction removal effect of the filtered water regardless of the forward direction or the reverse direction. In particular, when the flow is changed, it is possible to further expect a clogging suppression effect or a clogging removal effect of the filtered water.

  It verified about implementation of the stable water treatment by the water treatment apparatus 10 which concerns on one Example ((Q) cylindrical molded object is a separate molded object (refer FIG. 4)) of this invention. The results are shown in FIG.

Example 1
In Example 1, the flow direction of the water to be filtered W is bidirectional, the inner diameter of the hollow fiber membrane 21b constituting the membrane module 20 is 5 mm, the diameter A of the container 21a is 80 mm, and the inner diameter B is on the connecting members 22 and 23 side. = 80 mm, A / B = 1.00, in-membrane flow velocity 0.20 m / s in the forward direction, in-membrane flow velocity 0.20 m / s in the reverse direction, ratio thereof = 1.0, flow direction change timing 30 Every minute, MLSS concentration was set to 8000 mg / L.
In this case, the result of the filtration stability test (7 day continuous test) was good.

(Example 2)
In Example 2, the flow direction of the water to be filtered W is bidirectional, the inner diameter of the hollow fiber membrane 21b constituting the membrane module 20 is 5 mm, the diameter A of the container 21a is 80 mm, and the inner diameter B is on the connecting members 22 and 23 side. = 40 mm, A / B = 2.00, in-membrane flow velocity 0.20 m / s in the forward direction, in-membrane flow velocity 1.50 m / s in the reverse direction, their ratio = 7.5, flushing change timing of flow direction At the time of washing, the MLSS concentration was set to 2000 mg / L.
Even in this case, the result of the filtration stability test (7-day continuous test) was good.

(Example 3)
In Example 3, the flow direction of the water to be filtered W is bidirectional, the inner diameter of the hollow fiber membrane 21b constituting the membrane module 20 is 1.5 mm, the diameter A of the container 21a is 40 mm, and the connection members 22 and 23 are on the side. Inner diameter B = 65 mm, A / B = 0.62, in-membrane flow velocity 0.20 m / s in the forward direction, in-membrane flow velocity 1.00 m / s in the reverse direction, ratio = 5.0, flow direction change timing During reverse cleaning, the MLSS concentration was set to 2000 mg / L.
Even in this case, the result of the filtration stability test (7-day continuous test) was good.

Example 4
In Example 4, the flow direction of the water to be filtered W is bidirectional, the inner diameter of the hollow fiber membrane 21b constituting the membrane module 20 is 5 mm, the diameter A of the container 21a is 250 mm, and the inner diameter B is on the connecting members 22 and 23 side. = 250 mm, A / B = 1.00, in-membrane flow velocity 0.20 m / s in the forward direction, in-membrane flow velocity 0.20 m / s in the reverse direction, their ratio = 1.0, initial timing for changing the flow direction After ± 15% fluctuation with respect to the pressure, the MLSS concentration was set to 2000 mg / L.
Even in this case, the result of the filtration stability test (7-day continuous test) was good.

(Example 5)
In Example 5, the flow direction of the water to be filtered W is bidirectional, the inner diameter of the hollow fiber membrane 21b constituting the membrane module 20 is 5 mm, the diameter A of the container 21a is 250 mm, and the inner diameter B is on the connecting members 22 and 23 side. = 200 mm, A / B = 1.25, in-membrane flow velocity in forward direction 0.10 m / s, in-membrane flow velocity 2.50 m / s in reverse direction, their ratio = 25.0, reverse flow direction change timing At the time of orientation cleaning, MLSS concentration was set to 2000 mg / L.
Even in this case, the result of the filtration stability test (7-day continuous test) was good.

(Example 6)
In Example 6, the flow direction of the water to be filtered W is bidirectional, the inner diameter of the hollow fiber membrane 21b constituting the membrane module 20 is 10 mm, the diameter A of the container 21a is 250 mm, and the inner diameter B is on the connecting members 22 and 23 side. = 250 mm, A / B = 1.00, In-membrane flow velocity 0.15 m / s in the forward direction, In-membrane flow velocity 0.15 m / s in the reverse direction, ratio = 1.0, Initial timing for changing the flow direction After ± 15% fluctuation with respect to the pressure, the MLSS concentration was set to 8000 mg / L.
Even in this case, the result of the filtration stability test (7-day continuous test) was good.

(Example 7)
In Example 7, the flow direction of the water to be filtered W is bidirectional, the inner diameter of the hollow fiber membrane constituting the membrane module is 5 mm, the diameter of the container A = 40 mm, the inner diameter B of the connecting member B = 100 mm, and A / B = 0. .40, intramembrane flow velocity in the forward direction 0.20 m / s, intramembrane flow velocity 1.00 m / s in the reverse direction, and the flow direction change timing was set to MLSS concentration = 2000 mg / L during flushing washing.

  That is, in Example 7, compared to Comparative Examples 1 and 2, it is possible to supply filtered water in both the forward direction and the reverse direction, and the diameter A with respect to the inner diameter B is smaller than in the above example. Is different.

  Even in this case, the result of the filtration stability test (7-day continuous test) was good, but part of the turbidity component in the filtered water was found in the vicinity of the connecting member.

  This is because even if the water to be filtered is supplied to the membrane module from both directions, the concentrated water discharged from the membrane module is removed from the membrane module because the diameter A on the container side is too small relative to the inner diameter B on the connection member side. This is presumed to be due to retention within a range that does not affect the filtration stability.

  However, since the influence on the membrane filtration stability is slight, it can be taken as an embodiment.

Comparative example

  FIG. 15 shows the result of verifying the implementation of the stable water treatment according to the comparative example for comparison with the example of the present invention.

(Comparative Example 1)
Compared with Example 1 above, Comparative Example 1 is not configured to flow the water to be filtered in both forward and reverse directions with respect to the membrane module, and differs in that the MLSS concentration level is low. Yes.

  In this case, the result of the filtration stability test (continuous test for 7 days) was a result that a stable operation could not be performed because the obstruction adhered to the end face of the membrane.

  This is presumed that the membrane end face has been clogged because the water to be filtered is not configured to flow in both the forward and reverse directions with respect to the membrane module.

(Comparative Example 2)
Comparative Example 2 is different from Comparative Example 1 in that the in-membrane flow velocity in the forward direction is increased from 0.20 m / s to 0.80 m / s.

  Even in this case, the result of the filtration stability test (7-day continuous test) was a result that a stable operation could not be performed because the obstruction adhered to the end face of the membrane as in Comparative Example 1.

  This is because even if the flow rate in the membrane is increased, the membrane end face is clogged because the filtered water does not flow in both the forward and reverse directions with respect to the membrane module. Presumed to be.

  From the above results, as in the present invention, if the filtered water W is not supplied to the membrane module 20 from both directions, the membrane end face is likely to be clogged and stable water treatment can be performed. I found it difficult.

(Comparative Example 3)
In Comparative Example 3, the flow direction of the water to be filtered W is bidirectional, the inner diameter of the hollow fiber membrane constituting the membrane module is 5 mm, the diameter of the container A = 80 mm, the inner diameter B of the connecting member is 30 mm, and A / B = 2. .67, Intramembrane flow velocity 0.50 m / s in the forward direction, Intramembrane flow velocity 0.50 m / s in the reverse direction, MLSS concentration = 2000 mg / after changing the flow direction change timing by ± 15% or more with respect to the initial pressure L.

  That is, in Comparative Example 3, compared to Comparative Examples 1 and 2, it is possible to supply water to be filtered in both forward and reverse directions, and the diameter A with respect to the inner diameter B is made larger than that in the above embodiment. Is different.

  Even in this case, the result of the filtration stability test (7-day continuous test) was a result that a stable operation could not be performed because the obstruction adhered to the end face of the membrane.

  This is because even if the filtered water is supplied to the membrane module from both directions, the concentrated water discharged from the membrane module causes the retention because the inner diameter B on the connecting member side is smaller than the diameter A. In addition, it is presumed that the film end face has been clogged.

  From the above results, when the diameter A on the container 21a side of the membrane module 20 is not too large (2.0 or less) from the inner diameter B on the connecting members 22 and 23 side as in the present invention, the membrane end face It was found that clogging was likely to occur and it was difficult to carry out stable water treatment.

  From the above results, as in the present invention, when the diameter A on the container 21a side of the membrane module 20 is not within a range (0.5 or more) that is not too small with respect to the inner diameter B on the connection members 22 and 23 side, the membrane end face It was found that clogging was likely to occur and it was difficult to carry out stable water treatment.

  Since the water treatment apparatus of the present invention has the effect of preventing the occurrence of clogging of the water to be filtered and performing the water treatment stably, the internal pressure filtration using the hollow fiber membrane is performed. The present invention can be widely applied to water treatment apparatuses.

10 Water Treatment Device 11 Filtered Water Tank 12 First Pump (Drive Source)
13 Second pump (drive source)
14 Check valve (flow direction selector)
15 Check valve (flow direction selector)
16 Valve (Flow direction selector)
17 Valve (flow direction selector)
20 Membrane module 21 Main body 21a Container (tubular molded body)
21b Hollow fiber membrane 21c Sealing part 22 Connecting member 23 Connecting member 24a Inlet 24b Outlet 24c Outlet 30 Control part 31a, 32a First line 31b, 32b Second line 33a, 33b Pressure sensor 120 Membrane module 121a Container (cylinder) Shaped compact)
121b Hollow fiber membrane 121c Sealing portion 123 Connection member 220 Membrane module 221a Container (tubular molded body)
221b Hollow fiber membrane 221c Sealing portion 222, 223 Tubular body (connection member)
320 Membrane module 321c Sealing part 322, 323 Header pipe (connection member)
410 Water treatment device 412 Pump (drive source)
413 Blower (drive source)
416, 417, 418, 419 Valve (flow direction selector)
420 Membrane modules 431a, 432a First line 431b, 432b Second line W Filtered water

Claims (12)

A filtered water tank for storing the filtered water;
A cylindrical molded body having an opening, a hollow fiber membrane disposed in the cylindrical molded body, and an end of the hollow fiber membrane are fixed to the cylindrical molded body to seal the opening of the cylindrical molded body. A membrane module having a sealing part, and the membrane module performs membrane filtration by internal pressure filtration outside the water tank to be filtered,
A first line for connecting the filtered water tank and the membrane module, and supplying the filtered water from the filtered water tank to the membrane module;
A second line connecting the membrane module and the water tank to be filtered and returning the water to be filtered that has passed through the membrane module to the water tank to be filtered;
A flow direction selector that switches the flow direction of the filtered water in the axial direction in the membrane module to the forward direction or the opposite direction;
With
When the diameter of the end face of the sealing portion is A, and the inner diameter of the cylindrical molded body at a predetermined distance along the long axis direction of the hollow fiber membrane from the end face of the sealing portion is B, A / B Satisfies the following relational expression (1):
Water treatment equipment.
A / B ≦ 2.0 (1) The predetermined distance is a distance of depth 0.15A from the end face of the sealing portion.
The water treatment apparatus according to claim 1. The cylindrical molded body is an integrally molded product or a separate molded product,
The water treatment apparatus according to claim 1 or 2. The cylindrical molded body has any one of the following (P) and (Q):
The water treatment apparatus according to claim 3.
(P) When the cylindrical molded body is an integrally molded product, the cylindrical molded body is a container, the sealing portion is fixed to the container, and the inner diameter of the container is B.
(Q) When the cylindrical molded body is a separate molded product, the cylindrical molded body is constituted by a container and a connection member, the sealing portion is fixed to the container, and the inner diameter of the connection member is B And A controller that controls the flow direction of the filtered water by operating the flow direction selector;
The control unit is configured to satisfy the following relational expression (4) when the intra-membrane flow velocity in the forward direction or the reverse direction of the water to be filtered is set to a high flow velocity in the membrane and a low flow velocity in the membrane. Control the flow rate,
The water treatment apparatus of any one of Claim 1 to 4.
1 ≦ High flow rate in the membrane / Low flow rate in the membrane ≦ 30 (4) A single drive source for supplying the filtered water from the filtered water tank to the membrane module in both the forward direction and the reverse direction;
The water treatment apparatus of any one of Claim 1 to 5. The flow direction selection unit is a valve that opens and closes a flow path in at least one of the first line and the second line.
The water treatment apparatus of any one of Claim 1 to 6. A controller that controls the flow direction of the filtered water by operating the flow direction selector;
The control unit switches the flow direction of the water to be filtered from the forward direction to the reverse direction, and cleans the membrane module.
The water treatment apparatus of any one of Claim 1 to 7. The control unit performs back pressure cleaning that applies back pressure from the outer peripheral surface of the hollow fiber membrane.
The water treatment apparatus according to claim 8. A pressure sensor that detects the pressure of the water to be filtered supplied to the membrane module;
When the pressure difference detected by the pressure sensor with respect to the initial pressure immediately after switching the flow direction of the filtered water by the flow direction selection unit fluctuates by ± 15% or more, the control unit Controlling the flow direction selector so as to switch the direction in which the filtrate flows.
The water treatment apparatus according to claim 8 or 9. A flow sensor for detecting the flow rate of the water to be filtered in the membrane module,
When the differential pressure of the detection result in the flow rate sensor with respect to the detection result in the flow rate sensor immediately after switching the flow direction of the filtered water by the flow direction selection unit varies by ± 15% or more, Controlling the flow direction selector to switch the direction of flow of the filtered water,
The water treatment apparatus according to claim 8 or 9. The water treatment method in the water treatment apparatus of any one of Claim 1 to 11.

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