JP2022028429A - Water treatment method and water treatment equipment - Google Patents

Abstract

To provide a water treatment method and water treatment equipment which can perform stable treatment at low cost in water concentration treatment using a semipermeable module.SOLUTION: A water treatment method is provided, including: a semipermeable treatment step of passing treatment-object water including a dissolution solid component through a first space 14 using a semipermeable module, pressurizing the first space 14 and causing water included in the treatment object water to penetrate through a semipermeable film 12, thereby obtaining concentrated water, passing a part of the treatment object water or at least a part of the concentrated water through a second space 16, thereby obtaining diluted water; a first space outlet flow volume measurement step of measuring a flow volume of the concentrated water in a first space outlet; a second space inlet flow volume measurement step of measuring a flow volume of the treatment object water or the concentrated water in a second space inlet; and a second space outlet flow volume measurement step of measuring a flow volume of the diluted water in a second space outlet. In the water treatment method, the flow volume of the treatment object water in the first space inlet of the semipermeable module is calculated using each of the measured flow volumes.SELECTED DRAWING: Figure 1

Description

The present invention relates to a water treatment method and a water treatment apparatus for concentrating water containing a dissolved solid component (TDS) and the like.

In recent years, as a method for reducing the volume of wastewater from factories and the like, an evaporation method using an evaporator and a reverse osmosis method for recovering permeated water using a reverse osmosis membrane to reduce the volume of wastewater are known.

Further, as in Patent Document 1, water is discharged by flowing water to be treated or concentrated water thereof through the first space and the second space partitioned by the semipermeable membrane of the semipermeable membrane module and pressurizing the first space. A method of concentrating is known. Compared with the general reverse osmosis method, such a concentration method using a semipermeable membrane reduces the osmotic pressure difference between the first space and the second space, thereby highly concentrating wastewater with less energy consumption. The volume can be reduced.

The concentration method described in Patent Document 1 requires control of the flow rates in the first space and the second space of the membrane in order to stably reduce the volume of wastewater. It is necessary to install flow measurement equipment at each of the entrance and exit of the space.

However, since the first space line of the semipermeable membrane is pressurized and has a high pressure, the flow measuring device to be used needs to have high pressure resistance or a special ultrasonic type, and the initial cost. Leads to an increase in. Further, in the case of a device using a multi-stage semipermeable membrane module, if a flow rate measuring device is installed in each stage, the number of flow rate measuring devices increases as the number of stages increases, so that the initial cost further increases.

Japanese Unexamined Patent Publication No. 2018-069198

An object of the present invention is to provide a water treatment method and a water treatment apparatus capable of performing a stable treatment at low cost in a water concentration treatment using a semipermeable membrane module.

In the present invention, the water to be treated containing a dissolved solid component is passed through the first space by using a semi-transparent module having a first space and a second space partitioned by a semi-transparent film, and the first space is described. Concentrated water is obtained by pressurizing the space and allowing the water contained in the water to be treated to permeate through the semi-permeable film, and at the same time, a part of the water to be treated or at least a part of the concentrated water is formed in the second space. A semi-transmissive treatment step of passing water to obtain diluted water, a first space outlet flow rate measuring step of measuring the flow rate of concentrated water at the first space outlet of the semi-transparent module, and a first of the semi-transparent module. A second space inlet flow rate measuring step for measuring the flow rate of the water to be treated or concentrated water at the two-space inlet, and a second space outlet flow rate measuring step for measuring the flow rate of the diluted water at the second space outlet of the semitransparent film module. , And each flow rate measured in the first space outlet flow rate measurement step, the second space inlet flow rate measurement step, and the second space outlet flow rate measurement step is treated at the first space inlet of the semitransparent film module. It is a water treatment method that calculates the flow rate of water.

The present invention uses a semipermeable membrane module connected in multiple stages, which has a first space and a second space partitioned by a semipermeable membrane, to treat water containing a dissolved solid component in the first half of the first stage. Concentrated water is obtained by passing water through the first space of the permeable membrane module and pressurizing the first space to allow water contained in the water to be treated to permeate through the semipermeable membrane, and the concentrated water is further applied to the next. Concentrated water is obtained using the semipermeable membrane modules after the stage, and a part of the water to be treated or at least a part of the concentrated water is passed through the second space of the semipermeable membrane module of each stage to dilute it. The semipermeable membrane treatment step for obtaining water, the final stage first space outlet flow rate measurement step for measuring the flow rate of concentrated water at the first space outlet of the semipermeable membrane module in the final stage, and the most upstream flow on the second space side. A second space inlet flow rate measuring step for measuring the flow rate of water to be treated or concentrated water at the second space inlet of the semipermeable membrane module of the stage or each stage, and the most downstream stage or each stage on the second space side. A second space outlet flow rate measuring step for measuring the flow rate of diluted water at the second space outlet of the semipermeable membrane module, the final stage first space outlet flow measuring step, the second space inlet flow measuring step, and the above. A water treatment method for calculating the flow rate of water to be treated or concentrated water at the inlet of the first space of the semipermeable membrane module of the first stage or each stage from each flow rate measured in the second space outlet flow rate measuring step.

In the water treatment method, it is preferable to control the flow rate of the concentrated water or the water to be treated at the first space inlet to a predetermined value based on the calculated flow rate of the concentrated water or the water to be treated.

In the water treatment method, it is preferable that the pressure at the flow rate measuring points in the first space outlet flow rate measuring step, the second space inlet flow rate measuring step, and the second space outlet flow rate measuring step is 1 MPa or less.

In the present invention, a semipermeable membrane module having a first space and a second space partitioned by a semipermeable membrane is used to allow water to be treated containing a dissolved solid component to pass through the first space, and the first space is described. Concentrated water is obtained by pressurizing the space and allowing the water contained in the water to be treated to permeate through the semipermeable membrane, and at the same time, a part of the water to be treated or at least a part of the concentrated water is formed in the second space. A semipermeable membrane treatment means for obtaining diluted water by passing water, a first space outlet flow rate measuring means for measuring the flow rate of concentrated water at the first space outlet of the semipermeable membrane module, and a first semipermeable membrane module. A second space inlet flow rate measuring means for measuring the flow rate of the water to be treated or the concentrated water at the second space inlet, and a second space outlet flow rate measuring means for measuring the flow rate of the diluted water at the second space outlet of the semipermeable membrane module. , The flow rate of the water to be treated at the first space inlet of the semipermeable membrane module from each flow rate measured by the first space outlet flow rate measuring means, the second space inlet flow rate measuring means, and the second space outlet flow rate measuring means. It is a water treatment apparatus provided with a calculation means for calculating.

The present invention uses a semipermeable membrane module connected in multiple stages, which has a first space and a second space partitioned by a semipermeable membrane, to treat water containing a dissolved solid component in the first half of the first stage. Concentrated water is obtained by passing water through the first space of the permeable membrane module and pressurizing the first space to allow water contained in the water to be treated to permeate through the semipermeable membrane, and the concentrated water is further applied to the next. Concentrated water is obtained using the semipermeable membrane modules after the stage, and a part of the water to be treated or at least a part of the concentrated water is passed through the second space of the semipermeable membrane module of each stage to dilute it. The semipermeable membrane treatment means for obtaining water, the final stage first space outlet flow rate measuring means for measuring the flow rate of concentrated water at the first space outlet of the semipermeable membrane module in the final stage, and the uppermost stream on the second space side. A second space inlet flow rate measuring means for measuring the flow rate of water to be treated or concentrated water at the second space inlet of the semipermeable membrane module of the stage or each stage, and the most downstream stage or each stage on the second space side. A second space outlet flow rate measuring means for measuring the flow rate of diluted water at the second space outlet of the semipermeable membrane module, the final stage first space outlet flow rate measuring means, the second space inlet flow measuring means, and the second space. A water treatment apparatus comprising a calculation means for calculating the flow rate of water to be treated or concentrated water at the first space inlet of the semipermeable membrane module of the first stage or each stage from each flow rate measured by the outlet flow rate measuring means. Is.

The water treatment apparatus further includes a control means for controlling the flow rate of the concentrated water or the water to be treated at the first space inlet to a predetermined value based on the calculated flow rate of the concentrated water or the water to be treated. Is preferable.

In the water treatment apparatus, it is preferable that the pressure at the flow rate measuring point by the first space outlet flow rate measuring means, the second space inlet flow rate measuring means, and the second space outlet flow rate measuring means is 1 MPa or less.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a water treatment method and a water treatment apparatus capable of performing a stable treatment at low cost in a water concentration treatment using a semipermeable membrane module.

It is a schematic block diagram which shows an example of the water treatment apparatus which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the water treatment apparatus which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the water treatment apparatus which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the water treatment apparatus which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the water treatment apparatus which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the water treatment apparatus which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the water treatment apparatus which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the water treatment apparatus which concerns on embodiment of this invention.

Embodiments of the present invention will be described below. The present embodiment is an example of carrying out the present invention, and the present invention is not limited to the present embodiment.

An outline of an example of the water treatment apparatus according to the embodiment of the present invention is shown in FIG. 1, and the configuration thereof will be described.

The water treatment apparatus 1 shown in FIG. 1 uses a semipermeable membrane module having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane, such as a dissolved solid component (TDS). Concentrated water is obtained by passing the water to be treated containing water through the semipermeable membrane by passing the water to be treated to the first space and pressurizing the first space to allow the water contained in the water to be treated to permeate through the semipermeable membrane. As a semipermeable membrane treatment means for obtaining diluted water by passing a part of water, for example, a membrane module 10 is provided. The membrane module 10 has a first space 14 and a second space 16 partitioned by a semipermeable membrane 12. The water treatment device 1 may include a water tank to be treated to store the water to be treated.

In the water treatment apparatus 1 of FIG. 1, a pipe 24 is connected to the first space inlet of the membrane module 10, and a pipe 26 branched from the pipe 24 is connected to the second space inlet of the membrane module 10. A pipe 28 is connected to the first space outlet of the membrane module 10, and a pipe 30 is connected to the second space outlet of the membrane module 10.

A first space outlet flow rate measuring device 18 is installed in the pipe 28 as a first space outlet flow rate measuring means for measuring the flow rate (FI1) of concentrated water at the first space outlet of the membrane module 10. A second space inlet flow rate measuring device 20 is installed in the pipe 26 as a second space inlet flow rate measuring means for measuring the flow rate (FI2) of the water to be treated at the second space inlet of the membrane module 10. A second space outlet flow rate measuring device 22 is installed in the pipe 30 as a second space outlet flow rate measuring means for measuring the flow rate (FI3) of the diluted water at the second space outlet of the membrane module 10.

The water treatment device 1 of FIG. 1 uses a membrane module 10 having a first space 14 and a second space 16 partitioned by a semi-permeable membrane 12, and allows water to be treated to be transferred from the first space inlet of the membrane module 10 to the first space. By passing water from the 14 and the entrance of the second space to the second space 16 and pressurizing the first space 14, the water contained in the water to be treated in the first space 14 is seconded through the semitransparent membrane 12. It is a device that permeates the space 16 to concentrate water. That is, in the water treatment apparatus 1, the water to be treated is concentrated using the semipermeable membrane 12. The water treatment device 1 is a device that supplies water to be treated to both the first space 14 and the second space 16 of the membrane module 10 to perform concentration treatment.

In the water treatment apparatus 1, the water to be treated containing the dissolved solid component (TDS) is pressurized and sent from the inlet of the first space of the membrane module 10 to the first space 14 through the pipe 24, and is passed through the water. Further, the water to be treated is sent from the second space inlet of the membrane module 10 to the second space 16 through the pipe 26 branched from the pipe 24, and is passed through the water. A part of the water contained in the pressurized water to be treated permeates from the first space 14 to the second space 16 through the semipermeable membrane 12. At this time, since most of the dissolved solid components cannot pass through the semipermeable membrane 12, the water in the first space 14 that did not pass through the semipermeable membrane 12 is concentrated. On the other hand, in the second space 16, a part of the water to be treated that has passed through the pipe 26 and the permeated water having a low TDS concentration that has permeated through the semipermeable membrane 12 merge with each other, so that a diluting effect works. The concentrated water obtained in the first space 14 is discharged from the first space outlet through the pipe 28, and the diluted water obtained in the second space 16 is discharged from the second space outlet through the pipe 30. Here, in the membrane module 10, the first space 14 is pressurized, and the water contained in the water to be treated in the first space 14 is permeated into the second space 16 via the semipermeable membrane 12, and the first space 14 is used. Concentrated water is obtained in (concentration step), and diluted water is obtained in the second space 16 (diluting step). A part of the concentrated water obtained in the first space 14 is discharged to the outside of the system through the pipe 28.

Here, the pipes 24, 26 and the like function as supply means for supplying water to be treated to both the first space 14 and the second space 16 of the membrane module 10.

The diluted water obtained in the second space 16 may be discharged to the outside of the system through the pipe 30, or may be discharged to the diluted water tank as necessary, stored, and then discharged to the outside of the system. At least a part of the diluted water may be sent to the water tank to be treated and mixed with the water to be treated in the water tank to be treated. At least a part of the diluted water may be further sent to the reverse osmosis membrane treatment apparatus, and the reverse osmosis membrane treatment may be performed in the reverse osmosis membrane treatment apparatus (reverse osmosis membrane treatment step). The RO permeated water obtained by the reverse osmosis membrane treatment is discharged to the outside of the system. The RO concentrated water obtained by the reverse osmosis membrane treatment may be sent to a water tank to be treated and mixed with the water to be treated in the water tank to be treated.

As described above, the treated water (concentrated water) in which the substance such as the dissolved solid component is concentrated and the diluted water are obtained from the treated water containing the dissolved solid component and the like, which is the treatment target, and the treated water is obtained. Volume is reduced.

As described above, since the pipe 24 at the entrance of the first space of the membrane module 10 is pressurized and has a high pressure, the flow measuring device used for the pipe 24 has high pressure resistance and a special ultrasonic type. Things are needed, which leads to an increase in initial costs. In the water treatment method and the water treatment apparatus 1 according to the present embodiment, the first space outlet flow measuring device 18 and the second space inlet flow measuring device 20 are at the primary side outlet, the secondary side inlet and the secondary side outlet of the membrane module 10. , The second space outlet flow measuring device 22 is installed, and the flow measuring device is not installed at the primary side inlet, and the flow rate of the treated water at the primary side inlet is the primary side outlet, the secondary side inlet and the secondary side inlet. It is calculated from the value of each flow measuring device at the side outlet. That is, in the water treatment device 1, the flow rate measuring device is installed only at the primary side outlet, the secondary side inlet, and the secondary side outlet of the membrane module 10. As a result, the number of flow rate measuring devices used can be reduced, so that stable processing can be performed at low cost.

The flow rate of the water to be treated at the primary side inlet may be calculated from the values of the flow rate measuring devices of the primary side outlet, the secondary side inlet and the secondary side outlet, and may be calculated manually or automatically. In the case of automatic calculation, the water treatment device 1 calculates the flow rate of the water to be treated at the first space inlet from each flow rate measured by each flow rate measuring device of the primary side outlet, the secondary side inlet and the secondary side outlet. A calculation device may be provided as the calculation means. The calculation device may be connected to each of the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20, and the second space outlet flow rate measuring device 22 by electrical connection or the like. The calculation device is composed of, for example, a microcomputer and an electronic circuit composed of a calculation means such as a CPU for calculating a program, a storage means such as a ROM and a RAM for storing the program and the calculation result, and a primary side exit. It has a function of calculating the flow rate of the water to be treated at the first space inlet from each flow rate measured by each flow rate measuring device of the secondary side inlet and the secondary side outlet.

An outline of another example of the water treatment apparatus according to the embodiment of the present invention is shown in FIG. 2, and the configuration thereof will be described.

The water treatment apparatus 2 shown in FIG. 2 uses a semitransparent film module having a first space (concentration side) and a second space (permeation side) partitioned by a semitransparent film, and uses a dissolved solid component (TDS) or the like. Concentrated water is obtained by passing the water to be treated containing water through the first space and pressurizing the first space to allow the water contained in the water to be treated to permeate through the semi-permeable film, and to obtain concentrated water in the second space. As a semi-permeable membrane treatment means for obtaining diluted water by passing at least a part of the above, for example, a membrane module 10 is provided. The membrane module 10 has a first space 14 and a second space 16 partitioned by a semipermeable membrane 12. The water treatment device 1 may include a water tank to be treated to store the water to be treated.

In the water treatment apparatus 2 of FIG. 2, a pipe 24 is connected to the first space inlet of the membrane module 10. A pipe 28 is connected to the first space outlet of the membrane module 10. The pipe 32 branched from the pipe 28 is connected to the second space entrance of the membrane module 10. A pipe 34 is connected to the second space outlet of the membrane module 10.

On the downstream side of the branch point to the pipe 32 in the pipe 28, a first space outlet flow rate measuring device is used as a first space outlet flow rate measuring means for measuring the flow rate (FI1) of concentrated water at the first space outlet of the membrane module 10. 18 is installed. A second space inlet flow rate measuring device 20 is installed in the pipe 32 as a second space inlet flow rate measuring means for measuring the flow rate (FI2) of the water to be treated at the second space inlet of the membrane module 10. A second space outlet flow rate measuring device 22 is installed in the pipe 34 as a second space outlet flow rate measuring means for measuring the flow rate (FI3) of the diluted water at the second space outlet of the membrane module 10.

The water treatment device 2 of FIG. 2 uses a film module 10 having a first space 14 and a second space 16 partitioned by a semi-permeable film 12, and allows water to be treated to be transferred from the first space inlet of the film module 10 to the first space. At the same time as passing water through 14, at least a part of the concentrated water discharged from the first space outlet of the first space 14 of the membrane module 10 is passed through the second space inlet of the membrane module 10 to the second space 16, and the second space 16 is passed. By pressurizing one space 14, the water contained in the water to be treated in the first space 14 is permeated into the second space 16 through the semi-permeable film 12 to concentrate the water. That is, in the water treatment apparatus 1, the water to be treated is concentrated using the semipermeable membrane 12. The water treatment device 1 supplies water to be treated to the first space 14 of the membrane module 10, and supplies at least a part of the concentrated water obtained from the outlet of the first space 14 to the second space 16 of the membrane module 10. It is a device that performs concentration processing.

The water treatment method and the operation of the water treatment apparatus 2 according to the present embodiment will be described.

In the water treatment apparatus 2, the water to be treated containing the dissolved solid component (TDS) is pressurized and sent from the inlet of the first space of the membrane module 10 to the first space 14 through the pipe 24, and is passed through the water. A part of the water contained in the pressurized water to be treated permeates from the first space 14 to the second space 16 through the semipermeable membrane 12. At this time, since most of the dissolved solid components cannot pass through the semipermeable membrane 12, the water in the first space 14 that did not pass through the semipermeable membrane 12 is concentrated. On the other hand, in the second space 16, a part of the concentrated water passed through the pipe 32 and the permeated water having a low TDS concentration permeated through the semipermeable membrane 12 merge, so that the diluting effect works. The concentrated water obtained in the first space 14 is discharged from the first space outlet through the pipe 28, and at least a part of the concentrated water is passed through the pipe 32 branched from the pipe 28 and from the second space inlet of the membrane module 10. The liquid is sent to the two spaces 16 and water is passed through. The diluted water obtained in the second space 16 is discharged from the second space outlet through the pipe 34. Here, in the membrane module 10, the first space 14 is pressurized, and the water contained in the water to be treated in the first space 14 is permeated into the second space 16 via the semipermeable membrane 12, and the first space 14 is used. Concentrated water is obtained in (concentration step), and diluted water is obtained in the second space 16 (diluting step). A part of the concentrated water obtained in the first space 14 may be discharged to the outside of the system through the pipe 28. As described above, at least a part of the concentrated water is sent to and passed through the pipes 28 and 32 to the second space 16 of the membrane module 10.

Here, the pipes 24, 28, 32 and the like supply the water to be treated to the first space 14 of the membrane module 10, and at least a part of the concentrated water obtained from the outlet of the first space 14 is the first of the membrane module 10. It functions as a supply means for supplying the two spaces 16.

The diluted water obtained in the second space 16 may be discharged to the outside of the system through the pipe 34, or may be discharged to the diluted water tank as necessary, stored in the diluted water tank, and then discharged to the outside of the system. At least a part of the diluted water may be sent to the water tank to be treated and mixed with the water to be treated in the water tank to be treated. At least a part of the diluted water may be further sent to the reverse osmosis membrane treatment apparatus, and the reverse osmosis membrane treatment may be performed in the reverse osmosis membrane treatment apparatus (reverse osmosis membrane treatment step). The RO permeated water obtained by the reverse osmosis membrane treatment is discharged to the outside of the system. The RO concentrated water obtained by the reverse osmosis membrane treatment may be sent to a water tank to be treated and mixed with the water to be treated in the water tank to be treated.

As described above, the treated water (concentrated water) in which the substance such as the dissolved solid component is concentrated and the diluted water are obtained from the treated water containing the dissolved solid component and the like, which is the treatment target, and the treated water is obtained. Volume is reduced.

In the water treatment method and the water treatment apparatus 2 according to the present embodiment, the first space outlet flow measuring device 18 and the second space inlet flow measuring device 20 are at the primary side outlet, the secondary side inlet and the secondary side outlet of the membrane module 10. , The second space outlet flow measuring device 22 is installed, and the flow measuring device is not installed at the primary side inlet, and the flow rate of the treated water at the primary side inlet is the primary side outlet, the secondary side inlet and the secondary side inlet. It is calculated from the value of each flow measuring device at the side outlet. That is, in the water treatment device 2, the flow rate measuring device is installed only at the primary side outlet, the secondary side inlet, and the secondary side outlet of the membrane module 10. As a result, the number of flow rate measuring devices used can be reduced, so that stable processing can be performed at low cost.

In the water treatment method and the water treatment apparatus according to the present embodiment, the flow rate of the concentrated water or the treated water at the first space inlet becomes a predetermined value based on the calculated flow rate of the concentrated water or the treated water at the first space inlet. It is preferable to control so as to be. An example of the water treatment apparatus having such a configuration is shown in FIGS. 3 and 4.

In addition to the same configuration as the water treatment device 1 shown in FIG. 1, the water treatment device 3 shown in FIG. 3 has a pump 36 on the upstream side of the branch point to the pipe 26 in the pipe 24 and a second space inlet in the pipe 26. A valve 40 is provided on the upstream side of the installation point of the flow rate measuring device 20.

The pump 36 is, for example, a pressurizing pump that is driven at a rotation speed corresponding to an input drive frequency, sucks water to be treated, and discharges it to the membrane module 10. The pump 36 is equipped with, for example, an inverter 38 that outputs a drive frequency corresponding to the input command signal to the pump 36. The valve 40 is, for example, a proportional control valve that adjusts the opening degree based on the measured values of the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20, and the second space outlet flow rate measuring device 22.

The water treatment device 3 includes a control device 42 as a control means for controlling the flow rate of the water to be treated at the inlet of the first space to a predetermined value based on the calculated flow rate of the water to be treated at the inlet of the first space. You may. The control device 42 is connected to each of the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20, the second space outlet flow rate measuring device 22, the inverter 38, and the valve 40 by electrical connection or the like. May be good. The control device 42 is composed of, for example, a microcomputer and an electronic circuit composed of a calculation means such as a CPU for calculating a program, a storage means such as a ROM and a RAM for storing the program and the calculation result, and the flow rate of the pump 36. , It has a function of controlling the degree of opening / closing of the valve 40 and the like. The control device 42 may be the same device as the above calculation device, or may be another device.

In the water treatment device 3, in the same manner as in the water treatment device 1, the treated water containing the dissolved solid component and the like to be treated is diluted with the treated water (concentrated water) in which the substance such as the dissolved solid component is concentrated. Water is obtained, and the volume of water to be treated is reduced.

Here, for example, the flow rate (FI1) of the concentrated water at the first space outlet of the membrane module 10 is measured by the first space outlet flow rate measuring device 18 (first space outlet flow rate measuring step), and the second space inlet flow rate measurement is performed. The flow rate (FI2) of the water to be treated at the second space inlet of the film module 10 is measured by the device 20 (second space inlet flow rate measuring step), and the second space outlet flow rate measuring device 22 measures the second space of the film module 10. The flow rate (FI3) of the diluted water at the space outlet is measured (second space outlet flow measurement step). Then, for example, the subject at the first space inlet obtained from each flow rate (FI1, FI2, FI3) measured in the first space outlet flow rate measurement step, the second space inlet flow rate measurement step, and the second space outlet flow rate measurement step. Based on the flow rate of the treated water = FI1 + (FI3-FI2), the flow rate of the water to be treated at the inlet of the first space is controlled to be a predetermined value (control step).

For example, the control device 42 is obtained from each flow rate (FI1, FI2, FI3) measured by the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20, and the second space outlet flow rate measuring device 22. Based on the flow rate of the water to be treated at the inlet of the first space = FI1 + (FI3-FI2), the drive frequency is calculated using an arbitrary calculation formula so that the flow rate of the water to be treated at the inlet of the first space becomes a predetermined value. Then, a command signal corresponding to this calculated value may be output to the inverter 38 to control the pump 36, control the opening / closing degree of the valve 40, and control the flow rate of the water to be treated at the inlet of the first space.

In the water treatment method and the water treatment apparatus 3 according to the present embodiment, the first space outlet flow measuring device 18 and the second space inlet flow measuring device 20 are located at the primary side outlet, the secondary side inlet and the secondary side outlet of the membrane module 10. , The second space outlet flow measuring device 22 is installed, and the flow measuring device is not installed at the primary side inlet, and the flow rate of the treated water at the primary side inlet is the primary side outlet, the secondary side inlet and the secondary side inlet. It is calculated from the value of each flow measuring device at the side outlet. Then, the flow rate of the water to be treated at the primary inlet is adjusted from the calculated flow rate of the water to be treated at the primary inlet. As a result, the number of flow rate measuring devices used can be reduced, so that stable processing can be performed at low cost. Further, by controlling the flow rate of the water to be treated at the primary side inlet, more stable treatment can be performed.

In addition to the same configuration as the water treatment device 2 shown in FIG. 2, the water treatment device 4 shown in FIG. 4 has a pump 36 in the pipe 24 and an upstream side of the installation point of the second space inlet flow rate measuring device 20 in the pipe 32. Is equipped with a valve 40. The water treatment device 4 includes a control device 42 as a control means for controlling the flow rate of the water to be treated at the inlet of the first space to a predetermined value based on the calculated flow rate of the water to be treated at the inlet of the first space. You may. The control device 42 is connected to each of the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20, the second space outlet flow rate measuring device 22, the inverter 38, and the valve 40 by electrical connection or the like. May be good.

In the water treatment device 4, in the same manner as in the water treatment device 2, the treated water containing the dissolved solid component and the like to be treated is diluted with the treated water (concentrated water) in which the substance such as the dissolved solid component is concentrated. Water is obtained, and the volume of water to be treated is reduced.

Here, for example, the flow rate (FI1) of the concentrated water at the first space outlet of the membrane module 10 is measured by the first space outlet flow rate measuring device 18 (first space outlet flow rate measuring step), and the second space inlet flow rate measurement is performed. The flow rate (FI2) of the concentrated water at the inlet of the second space of the membrane module 10 is measured by the device 20 (second space inlet flow rate measuring step), and the second space of the membrane module 10 is measured by the second space outlet flow measuring device 22. The flow rate (FI3) of the diluted water at the outlet is measured (second space outlet flow measurement step). Then, for example, the subject at the first space inlet obtained from each flow rate (FI1, FI2, FI3) measured in the first space outlet flow rate measurement step, the second space inlet flow rate measurement step, and the second space outlet flow rate measurement step. Based on the flow rate of the treated water = FI1 + (FI3-FI2), the flow rate of the water to be treated at the inlet of the first space is controlled to be a predetermined value (control step).

For example, the control device 42 is obtained from each flow rate (FI1, FI2, FI3) measured by the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20, and the second space outlet flow rate measuring device 22. Based on the flow rate of the water to be treated at the inlet of the first space = FI1 + (FI3-FI2), the drive frequency is calculated using an arbitrary calculation formula so that the flow rate of the water to be treated at the inlet of the first space becomes a predetermined value. Then, a command signal corresponding to this calculated value may be output to the inverter 38 to control the pump 36, control the opening / closing degree of the valve 40, and control the flow rate of the water to be treated at the inlet of the first space.

In the water treatment method and the water treatment apparatus 4 according to the present embodiment, the first space outlet flow measuring device 18 and the second space inlet flow measuring device 20 are at the primary side outlet, the secondary side inlet and the secondary side outlet of the membrane module 10. , The second space outlet flow measuring device 22 is installed, and the flow measuring device is not installed at the primary side inlet, and the flow rate of the treated water at the primary side inlet is the primary side outlet, the secondary side inlet and the secondary side inlet. It is calculated from the value of each flow measuring device at the side outlet. Then, the flow rate of the water to be treated at the primary inlet is adjusted from the calculated flow rate of the water to be treated at the primary inlet. As a result, the number of flow rate measuring devices used can be reduced, so that stable processing can be performed at low cost. Further, by controlling the flow rate of the water to be treated at the primary side inlet, more stable treatment can be performed.

In the water treatment devices 3 and 4, when the flow rate of the water to be treated at the primary side inlet is less than a predetermined value, for example, the output value of the inverter 38 of the pump 36 is increased and the flow rate of the water to be treated at the primary side inlet is predetermined. It should be adjusted to the value. Alternatively, the valve 40 at the secondary inlet may be closed and the flow rate of the water to be treated at the primary inlet may be adjusted to a predetermined value.

When the flow rate of the water to be treated at the primary side inlet is higher than the predetermined value, for example, if the output value of the inverter 38 of the pump 36 is lowered and the flow rate of the water to be treated at the primary side inlet is adjusted to the predetermined value. good. Alternatively, the valve 40 at the secondary inlet may be opened and the flow rate of the water to be treated at the primary inlet may be adjusted to a predetermined value.

In the water treatment devices 3 and 4, the adjustment of the inverter 38 and the adjustment of the valve 40 may be performed automatically or manually.

The predetermined value of the flow rate of the water to be treated at the primary side inlet may be determined based on, for example, the flow rate range, the recovery rate, the amount of water to be treated, the salt concentration of the water to be treated, etc. determined by the membrane manufacturer or the like. The recovery rate (%) can be calculated as, for example, [(FI3-FI2) / (FI1 + FI3-FI2)] × 100.

In the water treatment method and the water treatment apparatus according to the present embodiment, a multi-stage semipermeable membrane module may be used. An example of the water treatment apparatus having such a configuration is shown in FIGS. 5, 6, 7, and 8.

The water treatment apparatus 5 shown in FIG. 5 uses a semipermeable membrane module connected in a plurality of stages and having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane. Water to be treated containing a dissolved solid component (TDS) or the like is passed through the first space of the semipermeable membrane module of the first stage, and the first space is pressurized to allow water contained in the water to be treated to permeate through the semipermeable membrane. Concentrated water is obtained by allowing the water to be concentrated, and the concentrated water is further obtained by using the semipermeable membrane modules of the next and subsequent stages, and a part of the water to be treated is placed in the second space of the semipermeable membrane module of each stage. Alternatively, as a semipermeable membrane processing means for obtaining diluted water by passing at least a part of concentrated water, for example, a first-stage membrane module 10a, a second-stage membrane module 10b, and a third-stage membrane module 10c are provided. Each membrane module has a first space 14 and a second space 16 partitioned by a semipermeable membrane 12. The water treatment device 5 is a diluted water tank 44a for storing the diluted water from the first stage membrane module 10a, a diluted water tank 44b for storing the diluted water from the second stage membrane module 10b, and diluted water from the third stage membrane module 10c. A diluted water tank 44c for storing the water may be provided. The water treatment device 5 supplies water to be treated to the first space and the second space of the first-stage membrane module, and sequentially supplies the concentrated water to the first space and the second space of the next-stage membrane module. It is a device that performs concentration processing.

In the water treatment apparatus 5 of FIG. 5, a pipe 46 is connected to the first space inlet of the first stage membrane module 10a via a pump 36. The pipe 54 branched from the pipe 46 is connected to the second space inlet of the membrane module 10a via the valve 40a. The second space outlet of the first-stage membrane module 10a and the inlet of the dilution tank 44a are connected by a pipe 56. The first space outlet of the first-stage membrane module 10a and the first space inlet of the second-stage membrane module 10b are connected by a pipe 48. The pipe 58 branched from the pipe 48 is connected to the second space inlet of the second stage membrane module 10b via the valve 40b. The second space outlet of the second stage membrane module 10b and the inlet of the dilution water tank 44b are connected by a pipe 60. The first space outlet of the second stage membrane module 10b and the first space inlet of the third stage membrane module 10c are connected by a pipe 50. The pipe 62 branched from the pipe 50 is connected to the second space inlet of the third stage membrane module 10c via the valve 40c. The second space outlet of the third stage membrane module 10c and the inlet of the dilution water tank 44c are connected by a pipe 64. A pipe 52 is connected to the first space outlet of the third stage membrane module 10c.

A first space outlet flow rate measuring device 18 is installed in the pipe 52 as a final stage first space outlet flow rate measuring means for measuring the flow rate (FI1) of concentrated water at the first space outlet of the final stage film module 10c. There is. In the pipes 54, 58, 62, the second space inlet flow rate measuring means for measuring the flow rate (FI2, FI4, FI6) of the water to be treated or the concentrated water at the second space inlet of the film modules 10a, 10b, 10c of each stage. The second space inlet flow rate measuring devices 20a, 20b, and 20c are installed, respectively. The pipes 56, 60, 64 have a second space outlet flow rate measuring means for measuring the flow rate (FI3, FI5, FI7) of the diluted water at the second space outlet of the film modules 10a, 10b, 10c of each stage. Space outlet flow rate measuring devices 22a, 22b, 22c are installed, respectively.

The pump 36 is, for example, a pressurizing pump that is driven at a rotation speed corresponding to an input drive frequency, sucks water to be treated, and discharges it to the first stage membrane module 10a. The pump 36 is equipped with, for example, an inverter 38 that outputs a drive frequency corresponding to the input command signal to the pump 36. The valves 40a, 40b, 40c are based on, for example, the measured values of the first space outlet flow measuring device 18, the second space inlet flow measuring device 20a, 20b, 20c, and the second space outlet flow measuring device 22a, 22b, 22c. It is a proportional control valve that adjusts the opening.

The water treatment device 5 sets the flow rate of the treated water or the concentrated water at the first space inlet of each stage to a predetermined value based on the calculated flow rate of the treated water or the concentrated water at the first space inlet of each stage. The control device 42 may be provided as the control means for controlling the above. The control device 42 includes a first space outlet flow rate measuring device 18, a second space inlet flow rate measuring device 20a, 20b, 20c, a second space outlet flow rate measuring device 22a, 22b, 22c, an inverter 38, and valves 40a, 40b, 40c. Each may be connected by an electrical connection or the like. The control device 42 is composed of, for example, a microcomputer and an electronic circuit composed of a calculation means such as a CPU for calculating a program, a storage means such as a ROM and a RAM for storing the program and the calculation result, and the flow rate of the pump 36. It has a function of controlling the degree of opening / closing of the valves 40a, 40b, 40c and the like.

The water treatment apparatus 5 uses a multi-stage membrane module having a first space 14 and a second space 16 partitioned by a semipermeable membrane 12, and the first space and the second space of the first-stage membrane module are treated. Water is supplied, and the concentrated water is sequentially supplied to the first space and the second space of the membrane module of the next stage, and by pressurizing the first space 14 of each stage, the water contained in the first space 14 is semipermeable. It is a device that concentrates water by allowing it to permeate through the second space 16 through the permeable membrane 12. That is, in the water treatment apparatus 5, the water to be treated is concentrated using the semipermeable membrane 12, and the concentrated water is further concentrated using the semipermeable membrane 12 of the next stage.

Specifically, in the water treatment apparatus 5, the water to be treated containing the dissolved solid component (TDS) is sent to the first space 14a of the first stage membrane module 10a through the pipe 46 by the pump 36, and is sent from the pipe 46. The branched water to be treated is sent to the second space 16a of the first stage film module 10a through the pipe 54. In the first-stage membrane module 10a, the first space 14a is pressurized and the water contained in the first space 14a is permeated into the second space 16a via the semipermeable membrane 12a (concentration step (first stage)). ), Diluting water is obtained in the second space 16a (dilution step (first stage)). The diluted water obtained in the second space 16a of the first-stage membrane module 10a is stored in the diluted water tank 44a as needed through the pipe 56, and then discharged to the outside of the system.

The concentrated water obtained in the first space 14a of the first-stage film module 10a is sent to the first space 14b of the second-stage film module 10b through the pipe 48, and the concentrated water branched from the pipe 48 is piped. The liquid is sent to the second space 16b of the second stage membrane module 10b through 58. In the second stage membrane module 10b, the first space 14b is pressurized and the water contained in the first space 14b is permeated into the second space 16b via the semipermeable membrane 12b (concentration step (second stage)). ), Diluting water is obtained in the second space 16b (dilution step (second stage)). The diluted water obtained in the second space 16b of the second stage membrane module 10b is stored in the diluted water tank 44b as needed through the pipe 60, and then discharged to the outside of the system.

The concentrated water obtained in the first space 14b of the second stage film module 10b is sent to the first space 14c of the third stage film module 10c through the pipe 50, and the concentrated water branched from the pipe 50 is piped. The liquid is sent to the second space 16c of the third stage membrane module 10c through 62. In the third-stage membrane module 10c, the first space 14c is pressurized and the water contained in the first space 14c is permeated into the second space 16c via the semipermeable membrane 12c (concentration step (third stage)). ), Diluting water is obtained in the second space 16c (dilution step (third stage)). The diluted water obtained in the second space 16c of the third-stage membrane module 10c is stored in the diluted water tank 44c as needed through the pipe 64, and then discharged to the outside of the system.

Here, the pump 36, the pipes 46, 48, 50, 54, 58, 62 and the like are provided in the first spaces 14a, 14b, 14c and the second spaces 16a, 16b, 16c of the membrane modules 10a, 10b, 10c of each stage. It functions as a supply means for supplying water to be treated or concentrated water.

The diluted water obtained in the second spaces 16a, 16b, 16c of the membrane modules 10a, 10b, 10c of each stage may be discharged to the outside of the system, or may be sent to the diluted water tanks 44a, 44b, 44c as needed. After being liquid and stored, it may be discharged to the outside of the system. At least a part of the diluted water may be mixed with the water to be treated of the first stage membrane module 10a. At least a part of the diluted water may be further sent to the reverse osmosis membrane treatment apparatus, and the reverse osmosis membrane treatment may be performed in the reverse osmosis membrane treatment apparatus (reverse osmosis membrane treatment step). The RO permeated water obtained by the reverse osmosis membrane treatment is discharged to the outside of the system. The RO concentrated water obtained by the reverse osmosis membrane treatment may be mixed with the water to be treated of the first stage membrane module 10a.

As described above, the treated water (concentrated water in the final stage) in which substances such as dissolved solid components are concentrated from the water to be treated containing the dissolved solid components, etc., and the diluted water (dilution in each stage), which are the treatment targets, are used. Water) is obtained, and the volume of water to be treated is reduced.

Here, for example, the flow rate (FI1) of the concentrated water at the first space outlet of the film module 10c in the final stage is measured by the first space outlet flow measuring device 18 (final stage first space outlet flow measuring step), and the first stage. The flow rate (FI2, FI4, FI6) of the water to be treated or the concentrated water at the second space inlet of the membrane modules 10a, 10b, 10c of each stage is measured by the two space inlet flow measuring devices 20a, 20b, 20c (second). The flow rate of diluted water (FI3, FI5, FI7) at the second space outlet of the membrane modules 10a, 10b, 10c of each stage is measured by the space inlet flow rate measuring step) and the second space outlet flow measuring devices 22a, 22b, 22c. (Second space outlet flow measurement step). Then, for example, each flow rate (FI1, FI2, FI3, FI4, FI5, FI6, FI7) measured in the final stage first space outlet flow rate measurement step, second space inlet flow rate measurement step, and second space outlet flow rate measurement step. Based on the flow rate of the treated water or concentrated water at the first space inlet of each stage, the flow rate of the treated water or concentrated water at the first space inlet of each stage is controlled to be a predetermined value ( Control process). For example, the flow rate of the water to be treated at the inlet of the first stage membrane module 10a is calculated as FI1 + (FI7-FI6) + (FI5-FI4) + (FI3-FI2) of the second stage membrane module 10b. The flow rate of concentrated water at the inlet of the first space is calculated as FI1 + (FI7-FI6) + (FI5-FI4), and the flow rate of concentrated water at the inlet of the first space of the third stage membrane module 10c is FI1 + (FI7-FI6). ).

For example, the control device 42 is each flow rate (FI1, FI1, 22c) measured by the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20a, 20b, 20c, and the second space outlet flow measuring device 22a, 22b, 22c. Flow rate of water to be treated at the first space inlet of the first stage membrane module 10a = FI1 + (FI7-FI6) + (FI5-FI4) + (FI3-) obtained from FI2, FI3, FI4, FI5, FI6, FI7) FI2) Flow rate of concentrated water at the first space inlet of the second stage membrane module 10b = FI1 + (FI7-FI6) + (FI5-FI4) = Flow rate of concentrated water at the first space inlet of the third stage membrane module 10c = Based on FI1 + (FI7-FI6), the drive frequency is calculated using an arbitrary calculation formula so that the flow rate of the water to be treated or the concentrated water at the inlet of the first space of each stage becomes a predetermined value, and this calculation value is obtained. The command signal corresponding to is output to the inverter 38 to control the pump 36, the open / close degree of the valves 40a, 40b, 40c is controlled, and the flow rate of the water to be treated or the concentrated water at the inlet of the first space of each stage is controlled. do it.

In the water treatment method and the water treatment apparatus 5 according to the present embodiment, the primary side outlet of the film module 10c in the final stage, the secondary side inlet and the secondary side outlet of the film modules 10a, 10b, 10c of each stage have a first space. The outlet flow rate measuring device 18, the second space inlet flow measuring device 20a, 20b, 20c, and the second space outlet flow measuring device 22a, 22b, 22c are installed, respectively, and the primary side inlets of the film modules 10a, 10b, 10c of each stage are installed. No flow measuring device is installed in, and the flow rate of the treated water or concentrated water at the primary side inlet of each stage is the primary side outlet of the final stage, the secondary side inlet of each stage, and the secondary side outlet of each stage. It is calculated from the value of each flow measuring device. That is, in the water treatment device 5, the flow rate measuring device is installed only at the primary side outlet of the membrane module 10 in the final stage, the secondary side inlet and the secondary side outlet of the membrane module 10 in each stage. Then, the flow rate of the treated water or the concentrated water at the primary side inlet of each stage is adjusted from the calculated flow rate of the treated water or the concentrated water at the primary side inlet of each stage. As a result, the number of flow rate measuring devices used can be significantly reduced, so that stable processing can be performed at low cost. Further, by controlling the flow rate of the water to be treated or the concentrated water at the primary inlet of each stage, more stable treatment can be performed.

The water treatment apparatus 6 shown in FIG. 6 uses a semipermeable membrane module connected in a plurality of stages and having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane. Water to be treated containing a dissolved solid component (TDS) or the like is passed through the first space of the semipermeable membrane module of the first stage, and the first space is pressurized to allow water contained in the water to be treated to permeate through the semipermeable membrane. Concentrated water is obtained by allowing the concentrated water to be obtained, and the concentrated water is further obtained by using the semipermeable membrane modules of the next and subsequent stages, and at least a part of the concentrated water is placed in the second space of the semipermeable membrane module of each stage. As a semipermeable membrane processing means for obtaining diluted water by passing water, for example, a first-stage membrane module 10a, a second-stage membrane module 10b, and a third-stage membrane module 10c are provided. Each membrane module has a first space 14 and a second space 16 partitioned by a semipermeable membrane 12. The water treatment device 6 is a diluted water tank 44a for storing the diluted water from the first stage membrane module 10a, a diluted water tank 44b for storing the diluted water from the second stage membrane module 10b, and diluted water from the third stage membrane module 10c. A diluted water tank 44c for storing the water may be provided. The water treatment device 6 supplies water to be treated to the first space of the first-stage membrane module, and sequentially supplies the concentrated water to the first space of the next-stage membrane module and its own second space for concentration treatment. It is a device that performs.

In the water treatment apparatus 6 of FIG. 6, a pipe 46 is connected to the first space inlet of the first stage membrane module 10a via a pump 36. The first space outlet of the first-stage membrane module 10a and the first space inlet of the second-stage membrane module 10b are connected by a pipe 48. The pipe 66 branched from the pipe 48 is connected to the second space inlet of the membrane module 10a via the valve 40a. The second space outlet of the first-stage membrane module 10a and the inlet of the dilution tank 44a are connected by a pipe 68. The first space outlet of the second stage membrane module 10b and the first space inlet of the third stage membrane module 10c are connected by a pipe 50. The pipe 70 branched from the pipe 50 is connected to the second space inlet of the membrane module 10b via the valve 40b. The second space outlet of the second stage membrane module 10b and the inlet of the dilution water tank 44b are connected by a pipe 72. A pipe 52 is connected to the first space outlet of the third stage membrane module 10c. The pipe 74 branched from the pipe 52 is connected to the second space inlet of the membrane module 10c via the valve 40c. The second space outlet of the third stage membrane module 10c and the inlet of the dilution tank 44c are connected by a pipe 76.

On the downstream side of the branch point to the pipe 74 in the pipe 52, as a final stage first space outlet flow rate measuring means for measuring the flow rate (FI1) of concentrated water at the first space outlet of the film module 10c in the final stage, the first A space outlet flow rate measuring device 18 is installed. The pipes 66, 70, 74 have a second space inlet flow rate measuring means for measuring the flow rate (FI2, FI4, FI6) of concentrated water at the second space inlet of the membrane modules 10a, 10b, 10c of each stage. Space inlet flow rate measuring devices 20a, 20b, 20c are installed, respectively. The pipes 68, 72, 76 have a second space outlet flow rate measuring means for measuring the flow rate (FI3, FI5, FI7) of the diluted water at the second space outlets of the film modules 10a, 10b, 10c of each stage. Space outlet flow rate measuring devices 22a, 22b, 22c are installed, respectively.

The pump 36 is, for example, a pressurizing pump that is driven at a rotation speed corresponding to an input drive frequency, sucks water to be treated, and discharges it to the first stage membrane module 10a. The pump 36 is equipped with, for example, an inverter 38 that outputs a drive frequency corresponding to the input command signal to the pump 36. The valves 40a, 40b, 40c are based on, for example, the measured values of the first space outlet flow measuring device 18, the second space inlet flow measuring device 20a, 20b, 20c, and the second space outlet flow measuring device 22a, 22b, 22c. It is a proportional control valve that adjusts the opening.

The water treatment device 6 controls to control the flow rate of the concentrated water at the first space inlet of each stage to a predetermined value based on the calculated flow rate of the water to be treated or the concentrated water at the first space inlet of each stage. As a means, a control device 42 may be provided. The control device 42 includes a first space outlet flow rate measuring device 18, a second space inlet flow rate measuring device 20a, 20b, 20c, a second space outlet flow rate measuring device 22a, 22b, 22c, an inverter 38, and valves 40a, 40b, 40c. Each may be connected by an electrical connection or the like. The control device 42 is composed of, for example, a microcomputer and an electronic circuit composed of a calculation means such as a CPU for calculating a program, a storage means such as a ROM and a RAM for storing the program and the calculation result, and the flow rate of the pump 36. It has a function of controlling the degree of opening / closing of the valves 40a, 40b, 40c and the like.

The water treatment apparatus 6 uses a multi-stage membrane module having a first space 14 and a second space 16 partitioned by a semi-permeable membrane 12, and supplies water to be treated to the first space of the first-stage membrane module. , The concentrated water is sequentially supplied to the first space of the membrane module of the next stage and its own second space, and by pressurizing the first space 14 of each stage, the water contained in the first space 14 is translucent. It is a device that concentrates water by allowing it to permeate through the second space 16 via 12. That is, in the water treatment apparatus 6, the water to be treated is concentrated using the semipermeable membrane 12, and the concentrated water is further concentrated using the semipermeable membrane 12 of the next stage.

Specifically, in the water treatment apparatus 6, the water to be treated containing the dissolved solid component (TDS) is sent to the first space 14a of the first stage membrane module 10a through the pipe 46 by the pump 36. In the first-stage membrane module 10a, the first space 14a is pressurized and the water contained in the first space 14a is permeated into the second space 16a via the semipermeable membrane 12a (concentration step (first stage)). ), Diluting water is obtained in the second space 16a (dilution step (first stage)). The concentrated water obtained in the first space 14a of the first-stage film module 10a is sent to the first space 14b of the second-stage film module 10b through the pipe 48, and the concentrated water branched from the pipe 48 is piped. The liquid is sent to the second space 16a of the first stage membrane module 10a through 66. The diluted water obtained in the second space 16a of the first-stage membrane module 10a is stored in the diluted water tank 44a as needed through the pipe 68, and then discharged to the outside of the system.

In the second stage membrane module 10b, the first space 14b is pressurized and the water contained in the first space 14b is permeated into the second space 16b via the semipermeable membrane 12b (concentration step (second stage)). ), Diluting water is obtained in the second space 16b (dilution step (second stage)). The concentrated water obtained in the first space 14b of the second stage film module 10b is sent to the first space 14c of the third stage film module 10c through the pipe 50, and the concentrated water branched from the pipe 50 is piped. The liquid is sent to the second space 16b of the second stage membrane module 10b through 70. The diluted water obtained in the second space 16b of the second stage membrane module 10b is stored in the diluted water tank 44b as needed through the pipe 72, and then discharged to the outside of the system.

In the third-stage membrane module 10c, the first space 14c is pressurized and the water contained in the first space 14c is permeated into the second space 16c via the semipermeable membrane 12c (concentration step (third stage)). ), Diluting water is obtained in the second space 16c (dilution step (third stage)). The concentrated water obtained in the first space 14c of the third stage membrane module 10c is discharged through the pipe 52, and the concentrated water branched from the pipe 52 passes through the pipe 74 and the second space 16c of the third stage membrane module 10c. The liquid is sent to. The diluted water obtained in the second space 16c of the third stage membrane module 10c is stored in the diluted water tank 44c as needed through the pipe 76, and then discharged to the outside of the system.

Here, the pump 36, the pipes 46, 48, 50, 66, 70, 74 and the like are provided in the first spaces 14a, 14b, 14c and the second spaces 16a, 16b, 16c of the membrane modules 10a, 10b, 10c of each stage. It functions as a supply means for supplying water to be treated or concentrated water.

The diluted water obtained in the second spaces 16a, 16b, 16c of the membrane modules 10a, 10b, 10c of each stage may be discharged to the outside of the system, or may be sent to the diluted water tanks 44a, 44b, 44c as needed. After being liquid and stored, it may be discharged to the outside of the system. At least a part of the diluted water may be mixed with the water to be treated of the first stage membrane module 10a. At least a part of the diluted water may be further sent to the reverse osmosis membrane treatment apparatus, and the reverse osmosis membrane treatment may be performed in the reverse osmosis membrane treatment apparatus (reverse osmosis membrane treatment step). The RO permeated water obtained by the reverse osmosis membrane treatment is discharged to the outside of the system. The RO concentrated water obtained by the reverse osmosis membrane treatment may be mixed with the water to be treated of the first stage membrane module 10a.

As described above, the treated water (concentrated water in the final stage) in which substances such as dissolved solid components are concentrated from the water to be treated containing the dissolved solid components, etc., and the diluted water (dilution in each stage), which are the treatment targets, are used. Water) is obtained, and the volume of water to be treated is reduced.

Here, for example, the flow rate (FI1) of the concentrated water at the first space outlet of the film module 10c in the final stage is measured by the first space outlet flow measuring device 18 (final stage first space outlet flow measuring step), and the first stage. The flow rate of concentrated water (FI2, FI4, FI6) at the second space inlet of the membrane modules 10a, 10b, 10c of each stage is measured by the two space inlet flow rate measuring devices 20a, 20b, 20c (second space inlet flow rate measurement). Step), the flow rate of diluted water (FI3, FI5, FI7) at the second space outlet of the membrane modules 10a, 10b, 10c of each stage is measured by the second space outlet flow measuring device 22a, 22b, 22c (first). (2) Space outlet flow measurement process). Then, for example, each flow rate measured in the final stage first space outlet flow rate measurement step, second space inlet flow rate measurement step, and second space outlet flow rate measurement step (FI1, FI2, FI3, FI4, FI5, FI6, FI7). Based on the flow rate of concentrated water at the first space inlet of each stage, the flow rate of concentrated water at the first space inlet of each stage is controlled to be a predetermined value (control step). For example, the flow rate of concentrated water at the inlet of the first stage membrane module 10a is calculated as FI1 + (FI7-FI6) + (FI5-FI4) + (FI3-FI2), and the second stage membrane module 10b of the second stage membrane module 10b. The flow rate of concentrated water at the inlet of one space is calculated as FI1 + (FI7-FI6) + (FI5-FI4), and the flow rate of concentrated water at the inlet of the first space of the third stage membrane module 10c is FI1 + (FI7-FI6). Is calculated as.

For example, the control device 42 is each flow rate (FI1, FI1, 22c) measured by the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20a, 20b, 20c, and the second space outlet flow measuring device 22a, 22b, 22c. Flow rate of water to be treated at the first space inlet of the first stage membrane module 10a = FI1 + (FI7-FI6) + (FI5-FI4) + (FI3-) obtained from FI2, FI3, FI4, FI5, FI6, FI7) FI2) Flow rate of concentrated water at the first space inlet of the second stage membrane module 10b = FI1 + (FI7-FI6) + (FI5-FI4) = Flow rate of concentrated water at the first space inlet of the third stage membrane module 10c = Based on FI1 + (FI7-FI6), the drive frequency is calculated using an arbitrary calculation formula so that the flow rate of the water to be treated or the concentrated water at the inlet of the first space of each stage becomes a predetermined value, and this calculation value is obtained. The command signal corresponding to is output to the inverter 38 to control the pump 36, the open / close degree of the valves 40a, 40b, 40c is controlled, and the flow rate of the water to be treated or the concentrated water at the inlet of the first space of each stage is controlled. do it.

In the water treatment method and the water treatment apparatus 6 according to the present embodiment, the primary side outlet of the film module 10c in the final stage, the secondary side inlet and the secondary side outlet of the film modules 10a, 10b, 10c of each stage have a first space. The outlet flow rate measuring device 18, the second space inlet flow measuring device 20a, 20b, 20c, and the second space outlet flow measuring device 22a, 22b, 22c are installed, respectively, and the primary side inlets of the film modules 10a, 10b, 10c of each stage are installed. No flow measuring device is installed in, and the flow rate of the treated water or concentrated water at the primary side inlet of each stage is the primary side outlet of the final stage, the secondary side inlet of each stage, and the secondary side outlet of each stage. It is calculated from the value of each flow measuring device. That is, in the water treatment device 6, the flow rate measuring device is installed only at the primary side outlet of the membrane module 10 in the final stage, the secondary side inlet and the secondary side outlet of the membrane module 10 in each stage. Then, the flow rate of the treated water or the concentrated water at the primary side inlet of each stage is adjusted from the calculated flow rate of the treated water or the concentrated water at the primary side inlet of each stage. As a result, the number of flow rate measuring devices used can be significantly reduced, so that stable processing can be performed at low cost. Further, by controlling the flow rate of the water to be treated or the concentrated water at the primary inlet of each stage, more stable treatment can be performed.

When a multi-stage membrane module is used, water may be passed in series on the second space side. FIG. 7 shows an example of a water treatment device having such a configuration. The water treatment apparatus 7 shown in FIG. 7 uses a semipermeable membrane module connected in a plurality of stages and having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane. Water to be treated containing a dissolved solid component (TDS) or the like is passed through the first space of the semipermeable membrane module of the first stage, and the first space is pressurized to allow water contained in the water to be treated to permeate through the semipermeable membrane. Concentrated water is obtained by allowing the concentrated water to be obtained, and the concentrated water is further obtained by using the semipermeable membrane modules of the next and subsequent stages, and at least a part of the concentrated water is placed in the second space of the semipermeable membrane module of each stage. As a semipermeable membrane processing means for obtaining diluted water by passing water, for example, a first-stage membrane module 10a, a second-stage membrane module 10b, and a third-stage membrane module 10c are provided. Each membrane module has a first space 14 and a second space 16 partitioned by a semipermeable membrane 12. The water treatment device 7 may include a diluted water tank 44 for storing the diluted water from the first stage membrane module 10a. The water treatment device 7 is a device that supplies water to be treated to the first space of the first-stage membrane module, and sequentially supplies the concentrated water to the first space of the next-stage membrane module to perform concentration treatment.

In the water treatment apparatus 7 of FIG. 7, a pipe 46 is connected to the first space inlet of the first stage membrane module 10a via a pump 36. The first space outlet of the first-stage membrane module 10a and the first space inlet of the second-stage membrane module 10b are connected by a pipe 48. The first space outlet of the second stage membrane module 10b and the first space inlet of the third stage membrane module 10c are connected by a pipe 50. A pipe 52 is connected to the first space outlet of the third stage membrane module 10c. The pipe 74 branched from the pipe 52 is connected to the second space inlet of the membrane module 10c via the valve 40. The second space outlet of the third stage membrane module 10c and the second space inlet of the second stage membrane module 10b are connected by a pipe 78. The second space outlet of the second stage membrane module 10b and the second space inlet of the first stage membrane module 10a are connected by a pipe 80. The second space outlet of the first-stage membrane module 10a and the inlet of the dilution water tank 44 are connected by a pipe 68.

On the downstream side of the branch point to the pipe 74 in the pipe 52, as a first space outlet flow rate measuring means for measuring the flow rate (FI1) of concentrated water at the first space outlet of the third stage membrane module 10c in the final stage. A space outlet flow rate measuring device 18 is installed. The pipe 74 has a second space inlet flow rate measuring means for measuring the flow rate (FI2) of concentrated water at the second space inlet of the third stage membrane module 10c, which is the most upstream stage on the second space 16 side. The space inlet flow rate measuring device 20 is installed. The pipe 68 is provided with a second space outlet flow rate measuring means for measuring the flow rate (FI3) of the diluted water at the second space outlet of the first stage membrane module 10a, which is the most downstream stage on the second space 16 side. A space outlet flow rate measuring device 22 is installed.

The pump 36 is, for example, a pressurizing pump that is driven at a rotation speed corresponding to an input drive frequency, sucks water to be treated, and discharges it to the first stage membrane module 10a. The pump 36 is equipped with, for example, an inverter 38 that outputs a drive frequency corresponding to the input command signal to the pump 36. The valve 40 is, for example, a proportional control valve that adjusts the opening degree based on the measured values of the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20, and the second space outlet flow rate measuring device 22.

In the water treatment apparatus 7, the flow rate of the treated water at the first space inlet of the first stage membrane module 10a becomes a predetermined value based on the calculated flow rate of the treated water at the first space inlet of the first stage membrane module 10a. A control device 42 may be provided as a control means for controlling the above. The control device 42 is connected to each of the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20, the second space outlet flow rate measuring device 22, the inverter 38, and the valve 40 by electrical connection or the like. May be good. The control device 42 is composed of, for example, a microcomputer and an electronic circuit composed of a calculation means such as a CPU for calculating a program, a storage means such as a ROM and a RAM for storing the program and the calculation result, and the flow rate of the pump 36. , It has a function of controlling the degree of opening / closing of the valve 40 and the like.

The water treatment device 7 uses a multi-stage film module having a first space 14 and a second space 16 partitioned by a semi-permeable film 12, and supplies water to be treated to the first space of the first-stage film module. , The concentrated water is sequentially passed through the first space of the next stage membrane module in series, and at least a part of the concentrated water of the final stage membrane module is supplied to its own second space, and the obtained diluted water is used. Water is passed in series to the second space 16 of the film module in the previous stage, and by pressurizing the first space 14 in each stage, the water contained in the first space 14 is passed through the semi-permeable film 12 to the second space. It is a device that concentrates water by allowing it to permeate through 16. That is, in the water treatment apparatus 7, the water to be treated is concentrated using the semipermeable membrane 12, and the concentrated water is further concentrated using the semipermeable membrane 12 of the next stage.

Specifically, in the water treatment apparatus 7, the water to be treated containing the dissolved solid component (TDS) is sent to the first space 14a of the first stage membrane module 10a through the pipe 46 by the pump 36. On the other hand, the diluted water sent through the second space 16c of the third-stage membrane module 10c and the second space 16b of the second-stage membrane module 10b, which will be described later, passes through the pipe 80 and is the first of the first-stage membrane module 10a. The liquid is sent to the two spaces 16a. In the first-stage membrane module 10a, the first space 14a is pressurized and the water contained in the first space 14a is permeated into the second space 16a via the semipermeable membrane 12a (concentration step (first stage)). ), Diluting water is obtained in the second space 16a (dilution step (first stage)). The concentrated water obtained in the first space 14a of the first-stage membrane module 10a is sent to the first space 14b of the second-stage membrane module 10b through the pipe 48. The diluted water obtained in the second space 16a of the first-stage membrane module 10a is stored in the diluted water tank 44 as needed through the pipe 68, and then discharged to the outside of the system.

In the second-stage membrane module 10b, the diluted water sent through the second space 16c of the third-stage membrane module 10c, which will be described later, is sent to the second space 16b of the second-stage membrane module 10b through the pipe 78. Will be done. The first space 14b is pressurized and the water contained in the first space 14b is permeated into the second space 16b via the semipermeable membrane 12b (concentration step (second stage)), and at the second space 16b. Diluted water is obtained (dilution step (second stage)). The concentrated water obtained in the first space 14b of the second stage membrane module 10b is sent to the first space 14c of the third stage membrane module 10c through the pipe 50. The diluted water obtained in the second space 16b of the second stage membrane module 10b is sent to the second space 16a of the first stage membrane module 10a through the pipe 80.

In the third-stage membrane module 10c, the concentrated water obtained in the first space 14c of the third-stage membrane module 10c is sent to the second space 16c through the pipes 52 and 74 as described below. The first space 14c is pressurized and the water contained in the first space 14c is permeated into the second space 16c via the semipermeable membrane 12c (concentration step (third stage)), and in the second space 16c. Diluted water is obtained (dilution step (third stage)). The concentrated water obtained in the first space 14c of the third stage membrane module 10c is discharged through the pipe 52, and the concentrated water branched from the pipe 52 passes through the pipe 74 and the second space 16c of the third stage membrane module 10c. The liquid is sent to. The diluted water obtained in the second space 16c of the third-stage membrane module 10c is sent to the second space 16b of the second-stage membrane module 10b through the pipe 78.

Here, the pump 36, the pipes 46, 48, 50, 52, 74, 78, 80 and the like are the first spaces 14a, 14b, 14c and the second spaces 16a, 16b of the membrane modules 10a, 10b, 10c of each stage. It functions as a supply means for supplying water to be treated or concentrated water to 16c.

The diluted water obtained in the second space 16a of the membrane module 10a may be discharged to the outside of the system, or may be discharged to the diluted water tank 44 as necessary, stored, and then discharged to the outside of the system. good. At least a part of the diluted water may be mixed with the water to be treated of the first stage membrane module 10a. At least a part of the diluted water may be further sent to the reverse osmosis membrane treatment apparatus, and the reverse osmosis membrane treatment may be performed in the reverse osmosis membrane treatment apparatus (reverse osmosis membrane treatment step). The RO permeated water obtained by the reverse osmosis membrane treatment is discharged to the outside of the system. The RO concentrated water obtained by the reverse osmosis membrane treatment may be mixed with the water to be treated of the first stage membrane module 10a.

As described above, the treated water (concentrated water in the final stage) in which substances such as dissolved solid components are concentrated from the water to be treated containing the dissolved solid components, etc., and the diluted water (dilution in each stage), which are the treatment targets, are used. Water) is obtained, and the volume of water to be treated is reduced.

Here, for example, the flow rate (FI1) of the concentrated water at the first space outlet of the film module 10c in the final stage is measured by the first space outlet flow measuring device 18 (final stage first space outlet flow measuring step), and the first stage. The flow rate (FI2) of the concentrated water at the second space inlet of the membrane module 10c, which is the most upstream stage on the second space 16 side, is measured by the two-space inlet flow measurement device 20 (second space inlet flow measurement step). The second space outlet flow measuring device 22 measures the flow rate (FI3) of the diluted water at the second space outlet of the membrane module 10a, which is the most downstream stage on the second space 16 side (second space outlet flow measuring step). ). Then, for example, the first stage obtained from each flow rate (FI1, FI2, FI3) measured in the final stage first space outlet flow rate measurement step, the second space inlet flow rate measurement step, and the second space outlet flow rate measurement step. Based on the flow rate of the water to be treated at the inlet of the first space = FI1 + (FI3-FI2), the flow rate of the water to be treated at the inlet of the first space of the first stage is controlled to be a predetermined value (control step).

For example, the control device 42 is obtained from each flow rate (FI1, FI2, FI3) measured by the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20, and the second space outlet flow rate measuring device 22. Based on the flow rate of the water to be treated at the inlet of the first stage film module 10a = FI1 + (FI3-FI2), the flow rate of the water to be treated at the inlet of the first stage film module 10a becomes a predetermined value. As described above, the drive frequency is calculated using an arbitrary calculation formula, the command signal corresponding to this calculation value is output to the inverter 38 to control the pump 36, and the open / close degree of the valve 40 is controlled to control the first space. The flow rate of the water to be treated at the inlet may be controlled.

In the water treatment method and the water treatment apparatus 7 according to the present embodiment, the primary side outlet of the membrane module 10c in the final stage, the secondary side inlet and the second space of the membrane module 10c which is the most upstream stage on the second space 16 side. A first space outlet flow measuring device 18, a second space inlet flow measuring device 20, and a second space outlet flow measuring device 22 are installed at the secondary side outlet of the membrane module 10a, which is the most downstream stage on the 16 side, respectively. No flow measuring device is installed at the primary side inlet of the stage membrane modules 10a, 10b, 10c and the secondary side inlet of the first stage membrane module 10a and the second stage membrane module 10b, and the first stage primary side. The flow rate of the water to be treated at the inlet is measured at each flow rate of the primary side outlet of the final stage, the secondary side inlet of the most upstream stage on the second space 16 side, and the secondary side outlet of the most downstream stage on the second space 16 side. Calculated from the value of the device. That is, in the water treatment apparatus 7, the primary side outlet of the membrane module 10 in the final stage, the secondary side inlet of the membrane module 10 in the most upstream stage on the second space 16 side, and the most downstream stage on the second space 16 side. A flow measuring device is installed only at the secondary outlet of the membrane module 10. Then, the flow rate of the water to be treated at the primary side inlet of the first stage is adjusted from the calculated flow rate of the water to be treated at the primary side inlet of the first stage. As a result, the number of flow rate measuring devices used can be significantly reduced, so that stable processing can be performed at low cost.

In the water treatment apparatus 7 of FIG. 7, when the water supply pressure on the second space side is required, for example, 1 MPa or more, or when a relay tank for concentrated water is required, a pump may be used for water supply on the second space side. FIG. 8 shows an example of a water treatment device having such a configuration. The water treatment apparatus 8 shown in FIG. 8 uses a semipermeable membrane module connected in a plurality of stages and having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane. Water to be treated containing a dissolved solid component (TDS) or the like is passed through the first space of the semipermeable membrane module of the first stage, and the first space is pressurized to allow water contained in the water to be treated to permeate through the semipermeable membrane. Concentrated water is obtained by allowing the concentrated water to be obtained, and the concentrated water is further obtained by using the semipermeable membrane modules of the next and subsequent stages, and at least a part of the concentrated water is placed in the second space of the semipermeable membrane module of each stage. As a semipermeable membrane processing means for obtaining diluted water by passing water, for example, a first-stage membrane module 10a, a second-stage membrane module 10b, and a third-stage membrane module 10c are provided. Each membrane module has a first space 14 and a second space 16 partitioned by a semipermeable membrane 12. The water treatment apparatus 8 may include a concentrated water tank 82 for storing the concentrated water from the third-stage membrane module 10c, and a diluted water tank 44 for storing the diluted water from the first-stage membrane module 10a. The water treatment device 8 is a device that supplies water to be treated to the first space of the first-stage membrane module, and sequentially supplies the concentrated water to the first space of the next-stage membrane module to perform concentration treatment.

In the water treatment apparatus 8 of FIG. 8, a pipe 46 is connected to the first space inlet of the first stage membrane module 10a via a pump 36. The first space outlet of the first-stage membrane module 10a and the first space inlet of the second-stage membrane module 10b are connected by a pipe 48. The first space outlet of the second stage membrane module 10b and the first space inlet of the third stage membrane module 10c are connected by a pipe 50. A pipe 52 is connected to the first space outlet of the third-stage membrane module 10c. The pipe 88 branched from the pipe 52 is connected to the inlet of the concentrated water tank 82. The outlet of the concentrated water tank 82 and the second space inlet of the membrane module 10c are connected by a pipe 90 via a pump 84. The second space outlet of the third stage membrane module 10c and the second space inlet of the second stage membrane module 10b are connected by a pipe 78. The second space outlet of the second stage membrane module 10b and the second space inlet of the first stage membrane module 10a are connected by a pipe 80. The second space outlet of the first-stage membrane module 10a and the inlet of the dilution water tank 44 are connected by a pipe 68.

On the downstream side of the branch point to the pipe 88 in the pipe 52, as a first space outlet flow rate measuring means for measuring the flow rate (FI1) of the concentrated water at the first space outlet of the third stage membrane module 10c in the final stage. A space outlet flow rate measuring device 18 is installed. On the upstream side of the pump 84 in the pipe 90, the second space inlet flow rate measurement for measuring the flow rate (FI2) of concentrated water at the second space inlet of the third stage membrane module 10c of the uppermost stage on the second space 16 side. As a means, a second space inlet flow rate measuring device 20 is installed. The second space is provided in the pipe 68 as a second space outlet flow rate measuring means for measuring the flow rate (FI3) of the diluted water at the second space outlet of the first stage membrane module 10a in the most downstream stage on the second space 16 side. The outlet flow rate measuring device 22 is installed.

The pump 36 is, for example, a pressurizing pump that is driven at a rotation speed corresponding to an input drive frequency, sucks water to be treated, and discharges it to the first stage membrane module 10a. The pump 36 is equipped with, for example, an inverter 38 that outputs a drive frequency corresponding to the input command signal to the pump 36. The pump 84 is, for example, a pressurizing pump that is driven at a rotation speed corresponding to an input drive frequency, sucks concentrated water, and discharges it to the third stage membrane module 10c. The pump 84 is equipped with, for example, an inverter 86 that outputs a drive frequency corresponding to the input command signal to the pump 84.

In the water treatment apparatus 8, the flow rate of the treated water at the first space inlet of the first stage membrane module 10a becomes a predetermined value based on the calculated flow rate of the treated water at the first space inlet of the first stage membrane module 10a. A control device 42 may be provided as a control means for controlling the above. The control device 42 is connected to each of the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20, the second space outlet flow rate measuring device 22, the inverter 38, and the inverter 86 by electrical connection or the like. May be good. The control device 42 is composed of, for example, a microcomputer and an electronic circuit composed of a calculation means such as a CPU for calculating a program, a storage means such as a ROM and a RAM for storing the program and the calculation result, and the flow rate of the pump 36. It has a function of controlling the flow rate of the pump 84 and the like.

The water treatment device 8 uses a multi-stage film module having a first space 14 and a second space 16 partitioned by a semi-permeable film 12, and supplies water to be treated to the first space of the first-stage film module. , The concentrated water is sequentially passed through the first space of the next stage membrane module in series, and at least a part of the concentrated water of the final stage membrane module is supplied to its own second space, and the obtained diluted water is used. Water is sequentially passed through the second space 16 of the membrane module in the previous stage in series, and by pressurizing the first space 14 in each stage, the water contained in the first space 14 is passed through the semi-permeable film 12 to the second space. It is a device that concentrates water by allowing it to permeate through 16. That is, in the water treatment apparatus 8, the water to be treated is concentrated using the semipermeable membrane 12, and the concentrated water is further concentrated using the semipermeable membrane 12 of the next stage.

Specifically, in the water treatment apparatus 8, the water to be treated containing the dissolved solid component (TDS) is sent to the first space 14a of the first stage membrane module 10a through the pipe 46 by the pump 36. On the other hand, the diluted water sent through the second space 16c of the third-stage membrane module 10c and the second space 16b of the second-stage membrane module 10b, which will be described later, passes through the pipe 80 and is the first of the first-stage membrane module 10a. The liquid is sent to the two spaces 16a. In the first-stage membrane module 10a, the first space 14a is pressurized and the water contained in the first space 14a is permeated into the second space 16a via the semipermeable membrane 12a (concentration step (first stage)). ), Diluting water is obtained in the second space 16a (dilution step (first stage)). The concentrated water obtained in the first space 14a of the first-stage membrane module 10a is sent to the first space 14b of the second-stage membrane module 10b through the pipe 48. The diluted water obtained in the second space 16a of the first-stage membrane module 10a is stored in the diluted water tank 44 as needed through the pipe 68, and then discharged to the outside of the system.

In the second-stage membrane module 10b, the diluted water sent through the second space 16c of the third-stage membrane module 10c, which will be described later, is sent to the second space 16b of the second-stage membrane module 10b through the pipe 78. Will be done. The first space 14b is pressurized and the water contained in the first space 14b is permeated into the second space 16b via the semipermeable membrane 12b (concentration step (second stage)), and at the second space 16b. Diluted water is obtained (dilution step (second stage)). The concentrated water obtained in the first space 14b of the second stage membrane module 10b is sent to the first space 14c of the third stage membrane module 10c through the pipe 50. The diluted water obtained in the second space 16b of the second stage membrane module 10b is sent to the second space 16a of the first stage membrane module 10a through the pipe 80.

In the third stage membrane module 10c, the concentrated water obtained in the first space 14c of the third stage membrane module 10c is sent to the second space 16c through the pipes 52, 88, the concentrated water tank 82, and the pipe 90 as described below. .. The first space 14c is pressurized and the water contained in the first space 14c is permeated into the second space 16c via the semipermeable membrane 12c (concentration step (third stage)), and in the second space 16c. Diluted water is obtained (dilution step (third stage)). The concentrated water obtained in the first space 14c of the third stage membrane module 10c is discharged through the pipe 52, and the concentrated water branched from the pipe 52 is stored in the concentrated water tank 82 through the pipe 88 as needed. .. The concentrated water stored in the concentrated water tank 82 is sent to the second space 16c of the third stage membrane module 10c through the pipe 90 by the pump 84. The diluted water obtained in the second space 16c of the third-stage membrane module 10c is sent to the second space 16b of the second-stage membrane module 10b through the pipe 78.

Here, the pumps 36, 84, the pipes 46, 48, 50, 52, 88, 90, 78, 80 and the like are the first space 14a, 14b, 14c and the second space of the membrane modules 10a, 10b, 10c of each stage. It functions as a supply means for supplying water to be treated or concentrated water to 16a, 16b, 16c.

The diluted water obtained in the second space 16a of the membrane module 10a may be discharged to the outside of the system, or may be discharged to the diluted water tank 44 as necessary, stored, and then discharged to the outside of the system. good. At least a part of the diluted water may be mixed with the water to be treated of the first stage membrane module 10a. At least a part of the diluted water may be further sent to the reverse osmosis membrane treatment apparatus, and the reverse osmosis membrane treatment may be performed in the reverse osmosis membrane treatment apparatus (reverse osmosis membrane treatment step). The RO permeated water obtained by the reverse osmosis membrane treatment is discharged to the outside of the system. The RO concentrated water obtained by the reverse osmosis membrane treatment may be mixed with the water to be treated of the first stage membrane module 10a.

As described above, the treated water (concentrated water in the final stage) in which substances such as dissolved solid components are concentrated from the water to be treated containing the dissolved solid components, etc., and the diluted water (dilution in each stage), which are the treatment targets, are used. Water) is obtained, and the volume of water to be treated is reduced.

Here, for example, the flow rate (FI1) of the concentrated water at the first space outlet of the film module 10c in the final stage is measured by the first space outlet flow measuring device 18 (final stage first space outlet flow measuring step), and the first stage. The flow rate (FI2) of the concentrated water at the second space inlet of the membrane module 10c, which is the most upstream stage on the second space 16 side, is measured by the two-space inlet flow measurement device 20 (second space inlet flow measurement step). The second space outlet flow measuring device 22 measures the flow rate (FI3) of the diluted water at the second space outlet of the membrane module 10a, which is the most downstream stage on the second space 16 side (second space outlet flow measuring step). ). Then, for example, the first stage obtained from each flow rate (FI1, FI2, FI3) measured in the final stage first space outlet flow rate measurement step, the second space inlet flow rate measurement step, and the second space outlet flow rate measurement step. Based on the flow rate of the water to be treated at the inlet of the first space = FI1 + (FI3-FI2), the flow rate of the water to be treated at the inlet of the first space of the first stage is controlled to be a predetermined value (control step).

For example, the control device 42 is obtained from each flow rate (FI1, FI2, FI3) measured by the first space outlet flow rate measuring device 18, the second space inlet flow rate measuring device 20, and the second space outlet flow rate measuring device 22. Based on the flow rate of the water to be treated at the inlet of the first stage film module 10a = FI1 + (FI3-FI2), the flow rate of the water to be treated at the inlet of the first stage film module 10a becomes a predetermined value. As described above, the drive frequency is calculated using an arbitrary calculation formula, the command signal corresponding to this calculation value is output to the inverter 38 to control the pump 36, and the command signal is output to the inverter 86 to control the pump 84. The flow rate of the water to be treated at the entrance of the first space may be controlled.

In the water treatment method and the water treatment apparatus 8 according to the present embodiment, the primary side outlet of the final stage membrane module 10c, the secondary side inlet of the most upstream stage membrane module 10c on the second space 16 side, and the second space 16 The first space outlet flow rate measuring device 18, the second space inlet flow measuring device 20, and the second space outlet flow measuring device 22 are installed at the secondary side outlet of the membrane module 10a in the most downstream stage on the side, respectively, and each stage A flow measuring device is not installed at the primary side inlet of the membrane modules 10a, 10b, 10c and the secondary side inlet of the first stage membrane module 10a and the second stage membrane module 10b, and the flow measuring device is not installed at the primary side inlet of the first stage. The flow rate of the water to be treated is the flow rate measuring device of the primary side outlet of the final stage, the secondary side inlet of the most upstream stage on the second space 16 side, and the secondary side outlet of the most downstream stage on the second space 16 side. Calculated from the value. That is, in the water treatment apparatus 8, the primary side outlet of the membrane module 10 in the final stage, the secondary side inlet of the membrane module 10 in the most upstream stage on the second space 16 side, and the most downstream stage on the second space 16 side. A flow measuring device is installed only at the outlet on the secondary side of the membrane module 10. Then, the flow rate of the water to be treated at the primary side inlet of the first stage is adjusted from the calculated flow rate of the water to be treated at the primary side inlet of the first stage. As a result, the number of flow rate measuring devices used can be significantly reduced, so that stable processing can be performed at low cost.

When a multi-stage membrane module such as the water treatment apparatus 5, 6, 7, 8 is used, the number of stages of the membrane module may be determined by the concentration of the target treated water or the like. For example, when it is desired to obtain a treatment water having a higher concentration from a water to be treated having a lower concentration, the number of stages of the membrane module unit may be increased. The water treatment method and the water treatment apparatus according to the present embodiment can be suitably applied when a multi-stage membrane module is used.

As the membrane module of each stage, a membrane module unit including a plurality of membrane modules connected in parallel may be used. The number of membrane modules in each membrane module unit may be determined by the flow rate of the water to be treated or the like.

A pipe may be provided to send the diluted water from the second space 16 of the membrane module of each stage to the second space 16 of the membrane module of the next stage.

The membrane module of one or more stages may be provided with a concentrated water tank or a diluted water tank, or the membrane module of each stage may be provided with a concentrated water tank or a diluted water tank.

Examples of the semi-permeable membrane 12 included in the membrane module include a semi-permeable membrane such as a reverse osmosis membrane (RO membrane), a forward osmosis membrane (FO membrane), and a nanofiltration membrane (NF membrane). The semipermeable membrane is preferably a reverse osmosis membrane, a forward osmosis membrane, or a nanofiltration membrane. When a reverse osmosis membrane, a forward osmosis membrane, or a nanofiltration membrane is used as the semipermeable membrane, the pressure of the water to be treated in the first space 14 is preferably 0.5 to 10.0 MPa.

The material constituting the semipermeable membrane 12 is not particularly limited, and examples thereof include a cellulosic resin such as a cellulose acetate resin, a polysulfone resin such as a polyethersulfone resin, and a polyamide resin. The material constituting the semipermeable membrane 12 is preferably a cellulose acetate-based resin.

Examples of the shape of the semipermeable membrane 12 include a flat membrane, a hollow fiber membrane, and a spiral membrane.

First space outlet flow measurement device, second space inlet flow measurement step, first space outlet flow measurement device 18, second space inlet flow measurement device 20, 20a, 20b, 20c, second in the first space outlet flow measurement step, second space inlet flow measurement step, second space outlet flow measurement step. The pressure at the flow rate measuring point by the space outlet flow measuring devices 22, 22a, 22b, 22c is preferably 1 MPa or less. The flow rate measuring device to be used may be any as long as it can measure the flow rate, and is not particularly limited. However, if the pressure at the flow rate measuring point is 1 MPa or less, a general-purpose flow meter can be used as the flow rate measuring device. Often, it is not necessary to use a special ultrasonic type with high pressure resistance.

The water to be treated may be water containing a substance such as a dissolved solid component (TDS), and is not particularly limited. For example, factory wastewater, salt water, seawater, chemical waste liquid, concentrated waste water after reverse osmosis membrane treatment, etc. Can be mentioned.

The TDS (dissolved solid component) contains, for example, chlorides such as sodium chloride, carbonates such as calcium carbonate and magnesium carbonate, and sulfates such as calcium sulfate and magnesium sulfate.

1,2,3,4,5,6,7,8 Water treatment equipment, 10 membrane module, 10a 1st stage membrane module, 10b 2nd stage membrane module, 10c 3rd stage membrane module, 12, 12a, 12b, 12c translucent membrane, 14, 14a, 14b, 14c first space, 16, 16a, 16b, 16c second space, 18 first space outlet flow measuring device, 20, 20a, 20b, 20c second space inlet flow measuring device , 22, 22a, 22b, 22c Second space outlet flow measuring device, 24, 26, 28, 30, 32, 34, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68,70,72,74,76,78,80,88,90 piping, 36,84 pumps, 38,86 inverters, 40,40a,40b, 40c valves, 42 controllers, 44,44a, 44b, 44c dilution Water tank, 82 concentrated water tank.

Claims (8)

Using a semi-transparent module having a first space and a second space partitioned by a semi-transparent film, water to be treated containing a dissolved solid component is passed through the first space, and the first space is pressurized. Concentrated water is obtained by allowing the water contained in the water to be treated to permeate through the semi-permeable film, and a part of the water to be treated or at least a part of the concentrated water is passed through the second space. Semi-transparent film treatment step to obtain diluted water and
The first space outlet flow rate measuring step for measuring the flow rate of concentrated water at the first space outlet of the semipermeable membrane module, and
The second space inlet flow rate measuring step for measuring the flow rate of the water to be treated or the concentrated water at the second space inlet of the semipermeable membrane module, and
A second space outlet flow rate measuring step for measuring the flow rate of diluted water at the second space outlet of the semipermeable membrane module, and a second space outlet flow rate measuring step.
Including
The flow rate of the water to be treated at the first space inlet of the semipermeable membrane module is calculated from each flow rate measured in the first space outlet flow rate measurement step, the second space inlet flow rate measurement step, and the second space outlet flow rate measurement step. A water treatment method characterized by calculation. Using a semipermeable membrane module connected in multiple stages, which has a first space and a second space partitioned by a semipermeable membrane, the water to be treated containing the dissolved solid component is transferred to the semipermeable membrane module of the first stage. Concentrated water is obtained by passing water through the first space and pressurizing the first space to allow the water contained in the water to be treated to permeate through the semipermeable membrane, and the concentrated water is further used in the next and subsequent stages. A semipermeable membrane module is used to obtain concentrated water, and a part of the water to be treated or at least a part of the concentrated water is passed through the second space of the semipermeable membrane module in each stage to obtain diluted water. Semipermeable membrane treatment process and
The final stage first space outlet flow rate measurement step for measuring the flow rate of concentrated water at the first space outlet of the semipermeable membrane module in the final stage, and the final stage first space outlet flow rate measurement step.
The second space inlet flow rate measuring step for measuring the flow rate of the water to be treated or the concentrated water at the second space inlet of the semipermeable membrane module at the most upstream stage on the second space side or each stage,
A second space outlet flow rate measuring step for measuring the flow rate of diluted water at the second space outlet of the semipermeable membrane module at the most downstream stage on the second space side or each stage.
Including
The first of the semipermeable membrane modules of the first stage or each stage from each flow rate measured in the final stage first space outlet flow rate measurement step, the second space inlet flow rate measurement step, and the second space outlet flow rate measurement step. A water treatment method characterized by calculating the flow rate of water to be treated or concentrated water at a space inlet. The water treatment method according to claim 1 or 2.
A water treatment method comprising controlling the flow rate of the concentrated water or the water to be treated at the first space inlet to a predetermined value based on the calculated flow rate of the concentrated water or the water to be treated. The water treatment method according to any one of claims 1 to 3.
A water treatment method characterized in that the pressure at a flow rate measurement point in the first space outlet flow rate measuring step, the second space inlet flow rate measuring step, and the second space outlet flow rate measuring step is 1 MPa or less. Using a semi-transparent module having a first space and a second space partitioned by a semi-transparent film, water to be treated containing a dissolved solid component is passed through the first space, and the first space is pressurized. Concentrated water is obtained by allowing the water contained in the water to be treated to permeate through the semi-permeable film, and a part of the water to be treated or at least a part of the concentrated water is passed through the second space. Semi-permeable membrane treatment means to obtain diluted water,
A first space outlet flow rate measuring means for measuring the flow rate of concentrated water at the first space outlet of the semipermeable membrane module,
A second space inlet flow rate measuring means for measuring the flow rate of the water to be treated or the concentrated water at the second space inlet of the semipermeable membrane module, and
A second space outlet flow rate measuring means for measuring the flow rate of diluted water at the second space outlet of the semipermeable membrane module,
From each flow rate measured by the first space outlet flow rate measuring means, the second space inlet flow rate measuring means, and the second space outlet flow rate measuring means, the flow rate of the water to be treated at the first space inlet of the semitransparent film module is measured. Calculation means to calculate and
A water treatment device characterized by being provided with. Using a semipermeable membrane module connected in multiple stages, which has a first space and a second space partitioned by a semipermeable membrane, the water to be treated containing the dissolved solid component is transferred to the semipermeable membrane module of the first stage. Concentrated water is obtained by passing water through the first space and pressurizing the first space to allow the water contained in the water to be treated to permeate through the semipermeable membrane, and the concentrated water is further used in the next and subsequent stages. A semipermeable membrane module is used to obtain concentrated water, and a part of the water to be treated or at least a part of the concentrated water is passed through the second space of the semipermeable membrane module in each stage to obtain diluted water. Membrane processing means and
The final stage first space outlet flow rate measuring means for measuring the flow rate of concentrated water at the first space outlet of the semipermeable membrane module in the final stage,
A second space inlet flow rate measuring means for measuring the flow rate of the water to be treated or the concentrated water at the second space inlet of the semipermeable membrane module at the most upstream stage on the second space side or each stage.
A second space outlet flow rate measuring means for measuring the flow rate of diluted water at the second space outlet of the semipermeable membrane module at the most downstream stage on the second space side or each stage.
The first of the semi-permeable film modules of the first stage or each stage from each flow rate measured by the final stage first space outlet flow rate measuring means, the second space inlet flow rate measuring means, and the second space outlet flow rate measuring means. A calculation means for calculating the flow rate of the water to be treated or concentrated water at the space entrance, and
A water treatment device characterized by being provided with. The water treatment apparatus according to claim 5 or 6.
A water treatment further comprising a control means for controlling the flow rate of the concentrated water or the water to be treated at the first space inlet to a predetermined value based on the calculated flow rate of the concentrated water or the water to be treated. Device. The water treatment apparatus according to any one of claims 5 to 7.
A water treatment apparatus characterized in that the pressure at a flow rate measuring point by the first space outlet flow rate measuring means, the second space inlet flow rate measuring means, and the second space outlet flow rate measuring means is 1 MPa or less.

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