JP2022040928A - Concentrating method, concentrating device, water treatment method, and water treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To concentrate a water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion at a high concentration at low cost, and to reduce the amount of waste liquid having a high ion concentration. I will provide a.
SOLUTION: A semipermeable membrane module 10 having a first space 14 and a second space 16 partitioned by a semipermeable membrane 12 is used to allow water to be treated to pass through the first space 14, and the first space 14 is used. To obtain concentrated water by allowing the water contained in the water to be treated to permeate through the semipermeable membrane 12, and to pass a part of the water to be treated or at least a part of the concentrated water through the second space 16. A semipermeable membrane treatment step of obtaining diluted water is included, and the water to be treated has a sulfate ion concentration of 20000 mg / L or more, and at least one of sodium ion and ammonium ion has a concentration of 10000 mg / L or more. Is.
[Selection diagram] Fig. 1

Description

The present invention comprises a concentrating method for concentrating water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion, a concentrating device, a water treatment method including the concentrating method, and a water treatment having the concentrating device. Regarding the device.

In recent years, a method of recovering valuable resources from wastewater containing sulfate ions, ammonium ions, sodium ions, etc. among wastewater discharged from a semiconductor factory or the like by using an evaporation method such as an evaporator or membrane distillation has been used. However, since the evaporation method requires a huge amount of energy, a method of reducing the volume of wastewater by a reverse osmosis membrane method is generally used in the preceding stage of the evaporation method as in Patent Document 1. Further, the discharge liquid generated by the evaporation method contains a large amount of impurities, and if it is discharged outside the system, there is a concern about environmental pollution. Therefore, as in Patent Document 2, the discharge liquid of the evaporation method is further treated. Is used.

As a method for concentrating ions contained in wastewater to a high concentration, a method combining a reverse osmosis membrane method and an evaporation method as described in Patent Document 1 is widely used. When the concentration of ions such as sulfate ion and ammonium ion in the water to be treated is high, the reverse osmosis membrane method may apply an excessive osmotic pressure, resulting in an increase in power cost and a sufficient volume reduction. When a highly concentrating evaporator such as an evaporator is used as the evaporation method, if the volume reduction by the reverse osmosis membrane method is insufficient, the reduction of energy cost may be insufficient, and the evaporation device. Since it is necessary to treat the high-concentration waste liquid generated in the above, the waste liquid treatment cost may be high.

Further, when a system for further treating the discharged liquid generated by the evaporation method is provided as in Patent Document 2, the initial cost and the running cost are increased.

Therefore, there is a need for a new technique capable of reducing the cost, concentrating the water to be treated containing high-concentration sulfate ions, ammonium ions, and the like, and reducing the amount of waste liquid having a high ion concentration.

Japanese Patent No. 3477526 Japanese Unexamined Patent Publication No. 2012-125745

An object of the present invention is a concentration method capable of concentrating water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion at a high concentration at low cost and reducing the amount of waste liquid having a high ion concentration. , A water treatment method including a concentration method thereof, and a water treatment device having the concentration device thereof.

In the present invention, a semipermeable membrane module having a first space and a second space partitioned by a semipermeable membrane is used to pass water to be treated through the first space and pressurize the first space. Concentrated water is obtained by allowing the water contained in the water to be treated to permeate through the semipermeable membrane, and a part of the water to be treated or at least a part of the concentrated water is passed through the second space. A method for concentrating the water to be treated, which comprises a semipermeable membrane treatment step for obtaining diluted water, wherein the water to be treated has a sulfate ion concentration of 20000 mg / L or more and at least one of sodium ion and ammonium ion has a concentration of 10000 mg / L or more. Is.

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, and uses a semipermeable membrane module in which the water to be treated is in the first stage of the semipermeable membrane module. Concentrated water is obtained by passing water through one 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 semipermeable to the next and subsequent stages. Concentrated water is obtained using the membrane module, and in the second space of the semipermeable membrane module of each stage, a part of the water to be treated or at least a part of the concentrated water or a dilution obtained from another semipermeable membrane module is obtained. A semipermeable membrane treatment step of passing at least a part of water to obtain diluted water is included, and the water to be treated has a sulfate ion concentration of 20000 mg / L or more and a concentration of at least one of sodium ion and ammonium ion. Is a concentration method having a concentration of 10000 mg / L or more.

In the concentration method, the permeation flux of the semipermeable membrane module is preferably in the range of 0.005 m / d to 0.05 m / d.

In the concentration method, it is preferable that the flow rate of the first space is larger than the flow rate of the second space.

In the concentration method, the semipermeable membrane module is preferably a hollow fiber membrane module.

In the present invention, a semipermeable membrane module having a first space and a second space partitioned by a semipermeable membrane is used to pass water to be treated through the first space and pressurize the first space. Concentrated water is obtained by allowing the water contained in the water to be treated to permeate through the semipermeable membrane, and a part of the water to be treated or at least a part of the concentrated water is passed through the second space. A concentrator comprising a semipermeable membrane treating means for obtaining diluted water, wherein the water to be treated has a sulfate ion concentration of 20000 mg / L or more and a concentration of at least one of sodium ion and ammonium ion of 10000 mg / L or more. Is.

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, and uses a semipermeable membrane module in which the water to be treated is in the first stage of the semipermeable membrane module. Concentrated water is obtained by passing water through one 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 semipermeable to the next and subsequent stages. Concentrated water is obtained using the membrane module, and in the second space of the semipermeable membrane module of each stage, a part of the water to be treated or at least a part of the concentrated water or a dilution obtained from another semipermeable membrane module is obtained. A semipermeable membrane treating means for passing at least a part of water to obtain diluted water is provided, and the water to be treated has a sulfate ion concentration of 20000 mg / L or more and a concentration of at least one of sodium ion and ammonium ion. Is a concentrator having a concentration of 10000 mg / L or more.

It is preferable that the concentrator further includes a permeation flux adjusting means for setting the permeation flux of the semipermeable membrane module in the range of 0.005 m / d to 0.05 m / d.

It is preferable that the concentrator further includes a flow rate adjusting means for making the flow rate in the first space larger than the flow rate in the second space.

In the concentrator, the semipermeable membrane module is preferably a hollow fiber membrane module.

The present invention is a water treatment method including the concentration method and including a reverse osmosis membrane treatment step before the semipermeable membrane treatment step.

In the water treatment method, after the semipermeable membrane treatment step, a recovery step of recovering sulfate ions and ammonium ions as ammonium sulfate crystals from the concentrated water obtained in the semipermeable membrane treatment step, and sulfate ions. It is preferable to include at least one post-treatment step in the recovery step of recovering the sodium ion as a crystal of sodium sulfate.

In the water treatment method, it is preferable to perform the reverse osmosis membrane treatment step for wastewater from a semiconductor factory.

The present invention is a water treatment apparatus including the concentrator and a reverse osmosis membrane treatment means provided in front of the semipermeable membrane treatment means.

In the water treatment apparatus, after the semipermeable membrane treatment means, a recovery means for recovering sulfate ions and ammonium ions as crystals of ammonium sulfate from the concentrated water obtained by the semipermeable membrane treatment means, and sulfate ions. It is preferable to provide at least one post-treatment means among the recovery means for recovering sodium ions as crystals of sodium sulfate.

In the water treatment apparatus, the reverse osmosis membrane treatment means is preferably a means for performing reverse osmosis membrane treatment on wastewater from a semiconductor factory.

According to the present invention, it is possible to concentrate water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion at a high concentration at low cost, and a concentration method and concentration capable of reducing the amount of waste liquid having a high ion concentration. An apparatus, a water treatment method including the enrichment method thereof, and a water treatment apparatus having the enrichment apparatus can be provided.

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

<Concentration method and concentrator>
An outline of an example of the concentrator according to the embodiment of the present invention is shown in FIG. 1, and the configuration thereof will be described.

The concentrator 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, and uses a semipermeable membrane ion, sodium ion, and ammonium ion. The water to be treated containing at least one of them is passed through the first space, and the first space is pressurized to allow the water contained in the water to be treated to permeate through the semipermeable membrane to obtain concentrated water and the second. As a semipermeable membrane treatment means for obtaining diluted water by passing a part of the water to be treated through the space, 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 concentrator 1 may include a water tank to be treated to store water to be treated.

In the concentrating device 1 of FIG. 1, a pipe 24 is connected to the first space inlet of the membrane module 10 via a pump 18, and a pipe 26 branched from the pipe 24 on the downstream side of the pump 18 is connected to the membrane via a valve 22. It is connected to the second space entrance of the module 10. A pipe 28 is connected to the first space outlet of the membrane module 10 via a valve 23, and a pipe 30 is connected to the second space outlet of the membrane module 10.

The pump 18 is, for example, a pressure pump that is driven at a rotation speed corresponding to an input drive frequency, sucks water to be treated, and pressurizes and discharges it to the membrane module 10. The pump 18 is equipped with, for example, an inverter 20 that outputs a drive frequency corresponding to the input command signal to the pump 18. The valve 22 and the valve 23 are, for example, valves whose opening / closing degree can be adjusted manually or automatically.

The concentrating device 1 of FIG. 1 uses a membrane module 10 having a first space 14 and a second space 16 partitioned by a semipermeable membrane 12, and water to be treated is transferred from the first space inlet of the membrane module 10 to the first space 14. By passing water from 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 of the first space 14 is passed through the semipermeable membrane 12 to the second space. It is a device that concentrates water by allowing it to permeate through 16. That is, in the concentrating device 1, the water to be treated is concentrated using the semipermeable membrane 12. The concentrating 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 the concentrating treatment.

In the concentrator 1, the water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion is first from the first space inlet of the membrane module 10 through the pipe 24 by the pump 18 with the valve 23 open. Pressurized liquid is sent to the space 14 and water is passed. 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 with the valve 22 open, 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 ions such as sulfate ions 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 passed through the pipe 26 and the permeated water having a low ion 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 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, the pump 18, and the like function as supply means for supplying the 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 outside of the system after being sent to the diluted water tank and stored as needed. 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. Further treatment may be performed on at least a part of the diluted water.

As described above, the treated water (concentrated water) in which ions such as sulfate ions are concentrated from the water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion, which is the treatment target, and diluted water. And the volume of the water to be treated is reduced.

By passing water to be treated containing sulfate ion, sodium ion and ammonium ion at least one of sulfate ion, sodium ion and ammonium ion through the first space 14 and the second space 16 of the membrane module 10, the first space 14 side of the semipermeable membrane 12 and the second space 14 are passed. The osmotic pressure difference on the second space 16 side can be reduced, and at least one of the high ion concentration sulfate ion, sodium ion and ammonium ion in the water to be treated can be concentrated with less energy consumption. That is, the water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion at a high concentration can be concentrated at low cost, and the amount of waste liquid having a high ion concentration can be reduced.

As an adjustment method for adjusting the supply flow rate of the water to be treated, the permeation water flow rate, and the concentrated water flow rate to the membrane module 10, for example, the following method may be performed.

The pump 18 is provided with an inverter 20 for controlling the drive frequency, and the flow rate of water to be treated to the membrane module 10 is adjusted. It is preferable to install the inverter 20 in the pump 18, but it is not necessary to install it. The water to be treated is supplied to both the first space 14 side and the second space 16 side, a valve 22 is provided in front of the inlet of the second space 16, a valve 23 is provided at the outlet of the first space 14, and the valve 22 and the valve 22 are provided. The ratio of the supply water flow rate to the first space 14 side and the supply water flow rate to the second space 16 side may be adjusted by manually or automatically adjusting the opening degree of the valve 23.

If the permeated water flow rate and the concentrated water flow rate are insufficient, the frequency of the inverter 20 of the pump 18 may be increased to increase the supply amount of the water to be treated.

A valve 23 whose opening / closing degree can be adjusted is provided at the outlet of the first space 14 of the pipe 28, and the flow rate of concentrated water and the pressure at the inlet of the first space 14 and the outlet of the first space 14 can be adjusted according to the opening degree of the valve 23. can.

By these operations, the pressure on the predetermined first space 14 side and various flow rates can be adjusted.

Further, the water to be treated may be supplied to the first space 14 side and the second space 16 side by separate pumps. When the water to be treated is supplied by separate pumps, each pump may be provided with an inverter for controlling the drive frequency.

By passing water to be treated at the same or similar concentration to both the first space 14 side and the second space 16 side, the osmotic pressure generated by the semipermeable membrane 12 can be reduced and the required pressure can be reduced. can. As a result, it is possible to concentrate the water to be treated at a concentration that could not be concentrated by the conventional reverse osmosis membrane method.

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

The concentrator 2 shown in FIG. 2 uses a semipermeable membrane module having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane, and uses a semipermeable membrane module, and sulfate ion, sodium ion, and ammonium ion. Concentrated water is obtained by passing the water to be treated containing at least one of them 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 at least a part of concentrated water through the space, 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 concentrator 2 may include a water tank to be treated to store water to be treated.

In the concentrating device 2 of FIG. 2, a pipe 24 is connected to the first space inlet of the membrane module 10 via a pump 18. A pipe 28 is connected to the first space outlet of the membrane module 10 via a valve 23. A pipe 34 branched from the pipe 28 on the upstream side of the valve 23 is connected to the second space inlet of the membrane module 10 via the valve 32. A pipe 36 is connected to the second space outlet of the membrane module 10.

The pump 18 is, for example, a pressure pump that is driven at a rotation speed corresponding to an input drive frequency, sucks water to be treated, and pressurizes and discharges it to the membrane module 10. The pump 18 is equipped with, for example, an inverter 20 that outputs a drive frequency corresponding to the input command signal to the pump 18. The valve 23 and the valve 32 are, for example, valves whose opening / closing degree can be adjusted manually or automatically.

The concentrating device 2 of FIG. 2 uses a membrane 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 supplied from the first space inlet of the membrane module 10 to the first space 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 to pass water to the first space 16. By pressurizing the 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 membrane 12, and the water is concentrated. That is, in the concentrating device 2, the water to be treated is concentrated using the semipermeable membrane 12. The concentrating device 2 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 concentrator 2 according to the present embodiment will be described.

In the concentrator 2, the water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion is first from the first space inlet of the membrane module 10 through the pipe 24 by the pump 18 with the valve 23 open. Pressurized liquid is sent to the space 14 and water is passed. 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 ions such as sulfate ions 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 34 and the permeated water having a low ion 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 34 branched from the pipe 28 with the valve 32 open. Liquid is sent from the entrance of the second space to the second space 16 and water is passed therethrough. The diluted water obtained in the second space 16 is discharged from the second space outlet through the pipe 36. 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 34 to the second space 16 of the membrane module 10.

Here, the pipes 24, 28, 34, the pump 18, etc. 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 membrane module. It functions as a supply means for supplying the second space 16 of 10.

The diluted water obtained in the second space 16 may be discharged to the outside of the system through the pipe 36, 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. Further treatment may be performed on at least a part of the diluted water.

As described above, the treated water (concentrated water) in which ions such as sulfate ions are concentrated from the water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion, which is the treatment target, and diluted water. And the volume of the water to be treated is reduced.

The treated water containing at least one of sulfate ion, sodium ion and ammonium ion is passed through the first space 14 of the membrane module 10, and at least one of the concentrated water obtained in the first space 14 is passed through the second space 16. By passing water through the section, the osmotic pressure difference between the first space 14 side and the second space 16 side of the semipermeable membrane 12 is reduced, and the high ion concentration of sulfate ion and sodium ion in the water to be treated is reduced with less energy consumption. At least one of the ammonium ions can be concentrated. That is, the water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion at a high concentration can be concentrated at low cost, and the amount of waste liquid having a high ion concentration can be reduced.

As an adjustment method for adjusting the supply flow rate of the water to be treated, the permeation water flow rate, and the concentrated water flow rate to the membrane module 10, for example, the following method may be performed.

The pump 18 is provided with an inverter 20 for controlling the drive frequency, and the flow rate of water to be treated to the membrane module 10 is adjusted. It is preferable to install the inverter 20 in the pump 18, but it is not necessary to install it. The water to be treated is supplied to the first space 14, a valve 23 is provided at the outlet of the first space 14, a valve 32 is provided in front of the inlet of the second space 16, and the opening of the valve 23 and the valve 32 is manually adjusted. The ratio of the water supply flow rate to the first space 14 side and the supply water flow rate to the second space 16 side may be adjusted by automatically adjusting.

If the permeated water flow rate and the concentrated water flow rate are insufficient, the frequency of the inverter 20 of the pump 18 may be increased to increase the supply amount of the water to be treated.

A valve 23 whose opening / closing degree can be adjusted is provided at the outlet of the first space 14 of the pipe 28, and the flow rate of concentrated water and the pressure at the inlet of the first space 14 and the outlet of the first space 14 can be adjusted according to the opening degree of the valve 23. can.

By these operations, the pressure on the predetermined first space 14 side and various flow rates can be adjusted.

Further, a concentrated water tank for storing concentrated water may be provided in the middle of the pipe 34, and the water to be treated may be supplied to the first space 14 side and the second space 16 side by separate pumps. When the water to be treated and the concentrated water are supplied by separate pumps, each pump may be provided with an inverter for controlling the drive frequency.

By passing the water to be treated to the first space 14 side and the concentrated water having a concentration close to that of the second space 16 side, the osmotic pressure generated by the semipermeable membrane 12 is reduced and the required pressure is obtained. Can be reduced. As a result, it is possible to concentrate the water to be treated at a concentration that could not be concentrated by the conventional reverse osmosis membrane method.

In the concentration method and the concentrator according to the embodiment of the present invention, the water to be treated has a sulfate ion concentration of 20000 mg / L or more, and at least one of sodium ion and ammonium ion has a concentration of 10000 mg / L or more. be. The sulfate ion concentration of the water to be treated is preferably 40,000 mg / L or more, more preferably in the range of 40,000 to 250,000 mg / L. The concentration of at least one of the sodium ion and the ammonium ion of the water to be treated is preferably 20000 mg / L or more, and more preferably in the range of 20000 to 100,000 mg / L.

The inlet pressure of the first space 14 is preferably in the range of 7 MPa or less, the inlet pressure of the second space 16 is preferably smaller than the inlet pressure of the first space 14, and the inlet of the second space 16 is set. The pressure is more preferably 50% or less of the inlet pressure of the first space 14. This can reduce the risk of damage to the semipermeable membrane due to pressure.

It is preferable that the flow rate on the first space 14 side is larger than the flow rate on the second space 16 side. If the flow rate on the first space 14 side is equal to or less than the flow rate on the second space 16 side, the permeation flux may become too high. For example, the pump 18, the inverter 20, the valve 22, the valve 23, the valve 32, and the like function as a flow rate adjusting means for making the flow rate in the first space larger than the flow rate in the second space.

If the permeation flux is too large, the concentration difference becomes large, which may cause problems such as an increase in fouling risk and an excessively high pressure. Further, if the permeation flux is too small, the concentration efficiency may deteriorate. From these points, the permeation flux of the membrane module 10 is preferably in the range of 0.005 m / d to 0.05 m / d, and preferably in the range of 0.015 m / d to 0.04 m / d. More preferred. The permeation flux is defined as a permeation flow rate per unit time and unit membrane area. For example, the pump 18, the inverter 20, the valve 22, the valve 23, the valve 32, and the like function as a permeation flux adjusting means for controlling the permeation flux within the above range.

The installation position and the number of valves are only examples, and may be larger than the numbers shown in FIGS. 1 and 2, and may be installed in at least one of the other pipes. Further, a flow meter may be installed as a flow rate measuring means for measuring the flow rate, and a pressure gauge may be installed as a pressure measuring means for measuring the pressure in at least one of the pipes.

In the concentration method and the concentration device according to the present embodiment, a multi-stage semipermeable membrane module may be used. An example of a concentrator having such a configuration is shown in FIGS. 3, 4, and 5. The concentrator shown in FIGS. 3, 4, and 5 has a structure in which semipermeable membrane modules are combined in series in three stages.

The concentrator 3 shown in FIG. 3 uses a semipermeable membrane module connected in a plurality of stages having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane, and sulfuric acid is used. Water to be treated containing ions and at least one of sodium ion and ammonium ion is passed through the first space of the semipermeable membrane module of the first stage, and the first space is pressurized to remove the water contained in the water to be treated. Concentrated water is obtained by permeating the semipermeable membrane, and the concentrated water is further obtained by using the semipermeable membrane modules of the next and subsequent stages, and the second space of the semipermeable membrane module of each stage is covered. As a semipermeable membrane treatment means for obtaining diluted water by passing a part of the treated water or a part of the concentrated water, for example, a first-stage membrane module 10a, a second-stage membrane module 10b, and a third-stage membrane module 10c are used. Be prepared. Each membrane module has a first space 14 and a second space 16 partitioned by a semipermeable membrane 12. The concentrator 3 prepares the diluted water tank 60a for storing the diluted water from the first-stage membrane module 10aa, the diluted water tank 60b for storing the diluted water from the second-stage membrane module 10b, and the diluted water from the third-stage membrane module 10c. A diluted water tank 60c for storing may be provided. The concentrator 3 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 to concentrate. It is a device that performs processing.

In the concentrating device 3 of FIG. 3, a pipe 40 is connected to the first space inlet of the first stage membrane module 10a via a pump 18. A pipe 42 branched from the downstream side of the pump 18 of the pipe 40 is connected to the second space inlet of the membrane module 10a via a valve 22a. The second space outlet of the first-stage membrane module 10a and the inlet of the dilution tank 60a are connected by a pipe 46. 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 44. The pipe 48 branched from the pipe 44 is connected to the second space inlet of the second stage membrane module 10b via the valve 22b. The second space outlet of the second stage membrane module 10b and the inlet of the dilution water tank 60b are connected by a pipe 52. 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 54 branched from the pipe 50 is connected to the second space inlet of the third stage membrane module 10c via the valve 22c. The second space outlet of the third stage membrane module 10c and the inlet of the dilution tank 60c are connected by a pipe 58. A pipe 56 is connected to the first space outlet of the third stage membrane module 10c via a valve 23.

The concentrator 3 uses a multi-stage membrane module having a first space 14 and a second space 16 partitioned by a semipermeable membrane 12, and water to be treated is used in the first space and the second space of the first-stage membrane module. 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 the water contained in the first space 14 is semipermeable by pressurizing the first space 14 of each stage. It is a device that concentrates water by allowing it to permeate through the second space 16 through the membrane 12. That is, in the concentrating device 3, 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 concentrator 3, the water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion is passed through the pipe 40 by the pump 18 with the valve 23 open, and the first stage membrane module 10a is used. The water to be treated, which has been sent to the first space 14a of the above and branched from the pipe 40, is sent to the second space 16a of the first stage membrane module 10a through the pipe 42 with the valve 22a open. 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 60a as needed through the pipe 46, 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 44, and the concentrated water branched from the pipe 44 is a valve. With the 22b open, the liquid is sent to the second space 16b of the second stage membrane module 10b through the pipe 48. 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 60b as needed through the pipe 52, and then discharged to the outside of the system.

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, and the concentrated water branched from the pipe 50 is a valve. With the 22c open, the liquid is sent to the second space 16c of the third stage membrane module 10c through the pipe 54. 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 60c as needed through the pipe 58, and then discharged to the outside of the system. The concentrated water obtained in the first space 14c of the third stage membrane module 10c is discharged to the outside of the system through the pipe 56.

Here, the pump 18, the pipes 40, 42, 44, 48, 50, 54 and the like are placed 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 60a, 60b, 60c 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. Further treatment may be performed on at least a part of the diluted water.

As described above, the treated water (concentrated water in the final stage) in which ions such as sulfate ions are concentrated from the treated water containing sulfate ion and at least one of sodium ion and ammonium ion, which is the treatment target. , Diluted water (diluted water in each stage) is obtained, and the volume of the water to be treated is reduced.

The concentrator 4 shown in FIG. 4 uses a semipermeable membrane module connected in a plurality of stages having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane, and sulfuric acid is used. Water to be treated containing ions and at least one of sodium ion and ammonium ion is passed through the first space of the semipermeable membrane module of the first stage, and the first space is pressurized to remove the water contained in the water to be treated. Concentrated water is obtained by permeating the semipermeable membrane, and the concentrated water is further concentrated in the second space of the semipermeable membrane module of each stage while obtaining concentrated water using the semipermeable membrane modules of the next and subsequent stages. As a semipermeable membrane processing means for obtaining diluted water by passing at least a part of 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 concentrator 4 uses the diluted water tank 62a for storing the diluted water from the first-stage membrane module 10a, the diluted water tank 62b for storing the diluted water from the second-stage membrane module 10b, and the diluted water from the third-stage membrane module 10c. A diluting water tank 62c for storing may be provided. The concentrator 4 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 to perform the concentration treatment. It is a device to perform.

In the concentrating device 4 of FIG. 4, a pipe 40 is connected to the first space inlet of the first stage membrane module 10a via a pump 18. 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 44. The pipe 64 branched from the pipe 44 is connected to the second space inlet of the membrane module 10a via the valve 32a. The second space outlet of the first-stage membrane module 10a and the inlet of the dilution tank 62a are connected by a pipe 66. 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 68 branched from the pipe 50 is connected to the second space inlet of the membrane module 10b via the valve 32b. The second space outlet of the second stage membrane module 10b and the inlet of the dilution water tank 62b are connected by a pipe 70. A pipe 56 is connected to the first space outlet of the third stage membrane module 10c via a valve 23. A pipe 72 branched from the pipe 56 on the upstream side of the valve 23 is connected to the second space inlet of the membrane module 10c via the valve 32c. The second space outlet of the third stage membrane module 10c and the inlet of the dilution tank 62c are connected by a pipe 74.

The concentrator 4 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 transferred to the semitransparent membrane 12. It is a device that concentrates water by allowing it to permeate through the second space 16. That is, in the concentrating device 4, 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 concentrator 4, the water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion is passed through the pipe 40 by the pump 18 with the valve 23 open, and the first stage membrane module 10a is used. The liquid is sent to the first space 14a of. 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 44, and the concentrated water branched from the pipe 44 is a valve. With the 32a open, the liquid is sent to the second space 16a of the first stage film module 10a through the pipe 64. The diluted water obtained in the second space 16a of the first-stage membrane module 10a is stored in the diluted water tank 62a as needed through the pipe 66, 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 membrane module 10b is sent to the first space 14c of the third stage membrane module 10c through the pipe 50, and the concentrated water branched from the pipe 50 is a valve. With the 32b open, the liquid is sent to the second space 16b of the second stage film module 10b through the pipe 68. The diluted water obtained in the second space 16b of the second stage membrane module 10b is stored in the diluted water tank 62b as needed through the pipe 70, 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 56, and the concentrated water branched from the pipe 56 is passed through the pipe 72 with the valve 32c open. The liquid is sent to the second space 16c of the module 10c. The diluted water obtained in the second space 16c of the third stage membrane module 10c is stored in the diluted water tank 62c as needed through the pipe 74, and then discharged to the outside of the system.

Here, the pump 18, the pipes 40, 44, 64, 50, 68, 56, 72 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 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 62a, 62b, 62c 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. Further treatment may be performed on at least a part of the diluted water.

As described above, the treated water (concentrated water in the final stage) in which ions such as sulfate ions are concentrated from the treated water containing sulfate ion and at least one of sodium ion and ammonium ion, which is the treatment target. , Diluted water (diluted water in each stage) is obtained, and the volume of the water to be treated is reduced.

When a multi-stage membrane module is used, water may be passed in series on the second space side. An example of the concentrator having such a configuration is shown in FIG. The concentrator 5 shown in FIG. 5 uses a semipermeable membrane module connected in a plurality of stages having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane, and sulfuric acid is used. Water to be treated containing ions and at least one of sodium ion and ammonium ion is passed through the first space of the semipermeable membrane module of the first stage, and the first space is pressurized to remove the water contained in the water to be treated. Concentrated water is obtained by permeating the semipermeable membrane, and the concentrated water is further concentrated in the second space of the semipermeable membrane module of each stage while obtaining concentrated water using the semipermeable membrane modules of the next and subsequent stages. As a semipermeable membrane treatment means for obtaining diluted water by passing at least a part of water or at least a part of diluted water obtained from another semipermeable membrane module, for example, the first stage membrane module 10a and the second stage membrane. A 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 concentrating device 5 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 processing.

In the concentrating device 5 of FIG. 5, a pipe 40 is connected to the first space inlet of the first stage membrane module 10a via a pump 18. 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 44. 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 56 is connected to the first space outlet of the third stage membrane module 10c via a valve 23. A pipe 76 branched from the pipe 56 on the upstream side of the valve 23 is connected to the second space inlet of the membrane module 10c via the valve 32. 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. A pipe 82 is connected to the second space outlet of the first-stage membrane module 10a.

The concentrator 5 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 passed through the first space of the membrane module of the next stage in series, and at least a part of the concentrated water of the membrane module of the final stage is supplied to its second space, and the obtained diluted water is used. Water is passed in series to the second space of the membrane module in the previous stage, and by pressurizing the first space 14 in each stage, the water contained in the first space 14 is transferred to the second space 16 via the translucent membrane 12. It is a device that permeates and concentrates water. That is, in the concentrating device 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 concentrator 5, the water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion is passed through the pipe 40 by the pump 18 with the valve 23 open, and the first stage membrane module 10a is used. The liquid is sent to the first space 14a of. 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 44. The diluted water obtained in the second space 16a of the first-stage membrane module 10a is discharged to the outside of the system through the pipe 82.

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 56 and 76 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 56, and the concentrated water branched from the pipe 56 is discharged through the pipe 76 with the valve 32 open. The liquid is sent to the second space 16c of the module 10c. 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 18, the pipes 40, 44, 50, 56, 76, 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 the water to be treated, concentrated water, or diluted 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 as necessary, stored, and then 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. Further treatment may be performed on at least a part of the diluted water.

As described above, the treated water (concentrated water in the final stage) in which ions such as sulfate ions are concentrated from the treated water containing sulfate ion and at least one of sodium ion and ammonium ion, which is the treatment target. , Diluted water (diluted water in the final stage) is obtained, and the volume of the water to be treated is reduced.

In the concentrating device 3 shown in FIG. 3, the concentrating device 4 shown in FIG. 4, and the concentrating device 5 shown in FIG. 5, the water to be treated supplied to each membrane module is concentrated from the first stage to the subsequent membrane modules. As it goes on, the concentration becomes high. Since it is finally concentrated to a high concentration, this method, which can reduce the osmotic pressure, can concentrate to a concentration that was difficult to concentrate due to the influence of the osmotic pressure by the conventional reverse osmosis membrane method. Will be.

When the water to be treated is supplied to the first-stage membrane module 10a, for example, a pressure of 7 MPa or less is applied, and the water to be treated is supplied to the subsequent membrane module by the pressure applied to the first-stage membrane module 10a. Just do it. The inlet pressure of the first space 14 in each film module is preferably in the range of 7 MPa or less, the inlet pressure of the second space 16 is preferably smaller than the inlet pressure of the first space 14, and the second It is more preferable that the inlet pressure of the space 16 is 50% or less of the inlet pressure of the first space 14. This can reduce the risk of damage to the semipermeable membrane due to pressure.

It is preferable that the flow rate on the first space 14 side in each membrane module 10 is larger than the flow rate on the second space 16 side. If the flow rate on the first space 14 side is equal to or less than the flow rate on the second space 16 side, the flow rate on the first space 14 side of the subsequent membrane module may be insufficient. For example, the flow rate of the pump 18, the inverter 20, the valves 22a, 22b, 22c, the valve 23, the valves 32a, 32b, 32c, the valve 32, etc. is adjusted so that the flow rate in the first space is larger than the flow rate in the second space. Functions as a means.

If the permeation flux is too large, the concentration polarization of the membrane surface becomes large, which may cause problems such as an increase in fouling risk and an excessively high pressure. Further, if the permeation flux is too small, the concentration efficiency may deteriorate. From these points, the permeation flux of each membrane module 10 is preferably in the range of 0.005 m / d to 0.05 m / d, and preferably in the range of 0.015 m / d to 0.04 m / d. Is more preferable. For example, the pump 18, the inverter 20, the valves 22a, 22b, 22c, the valve 23, the valves 32a, 32b, 32c, the valve 32 and the like function as the permeation flux adjusting means for controlling the permeation flux within the above range.

When the water to be treated to be passed through the first-stage membrane module 10a has a sulfate ion concentration of 20000 mg / L or more and at least one of sodium ion and ammonium ion has a concentration of 10000 mg / L or more, the final stage. The concentrated water discharged from the first space 14 side of the membrane module 10 is preferably ammonium sulfate or sodium sulfate having a concentration of 25% by weight or more, and more preferably 30% by weight or more.

The installation position and the number of valves are only examples, and may be larger than the numbers shown in FIGS. 3, 4, and 5, and may be installed in at least one of the other pipes. Further, a flow meter may be installed as a flow rate measuring means for measuring the flow rate, and a pressure gauge may be installed as a pressure measuring means for measuring the pressure in at least one of the pipes.

Further, FIGS. 3, 4, and 5 are examples of the apparatus configuration, and the arrangement of the semipermeable membrane modules, the supply method of the supplied water, and the like may be appropriately changed.

Since the concentrator in FIG. 5 passes water in series to each of the first space and the second space of the membrane module in each stage, the total amount of water is suppressed as compared with the concentrators in FIGS. 3 and 4. This is preferable because the power of the pump can be reduced.

In the concentrating method and the concentrating device according to the present embodiment, a multi-stage membrane module may be used, and a membrane module unit including a plurality of membrane modules connected in parallel may be used as the membrane module of each stage. Examples of a concentrator having such a configuration are shown in FIGS. 6 and 7. In the concentrators shown in FIGS. 6 and 7, the semipermeable membrane modules are combined in parallel in 4 rows in the first stage, and the semipermeable membrane modules are combined in parallel in 4 rows in the second stage, and the semipermeable membrane is combined in the third stage. It has a structure in which modules are combined in parallel in two rows and semipermeable membrane modules are combined in parallel in two rows in the fourth stage and connected in series in four stages.

The concentrator 6 shown in FIG. 6 uses a semipermeable membrane module connected in a plurality of stages having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane, and sulfuric acid is used. Water to be treated containing ions and at least one of sodium ion and ammonium ion is passed through the first space of the semipermeable membrane module of the first stage, and the first space is pressurized to remove the water contained in the water to be treated. Concentrated water is obtained by permeating the semipermeable membrane, and the concentrated water is further obtained by using the semipermeable membrane modules of the next and subsequent stages, and the second space of the semipermeable membrane module of each stage is covered. As a semipermeable membrane treatment means for obtaining diluted water by passing a part of the treated water or a part of the concentrated water, for example, the first stage membrane module unit 100a, the second stage membrane module unit 100b, and the third stage membrane module. The unit 100c is provided with a fourth stage membrane module unit 100d. The first-stage membrane module unit 100a includes, for example, four membrane modules connected in parallel, and the second-stage membrane module unit 100b includes, for example, four membrane modules connected in parallel. The third-stage membrane module unit 100c includes, for example, two membrane modules connected in parallel, and the fourth-stage membrane module unit 100d includes, for example, two membrane modules connected in parallel. Each membrane module 10 has a first space 14 and a second space 16 partitioned by a semipermeable membrane 12. The concentrating device 6 may include a water tank 84 to be treated for storing water to be treated, and a concentrating water tank 86 for storing concentrated water from the fourth-stage membrane module unit 100d. The concentrator 6 supplies water to be treated to the first space and the second space of each membrane module of the first stage membrane module unit, and the concentrated water is sequentially supplied to the first membrane module of each membrane module of the next stage membrane module unit. It is a device that supplies to the space and the second space to perform concentration processing.

In the concentrating device 6 of FIG. 6, the outlet of the water tank 84 to be treated and the first space inlet and the second space inlet of each membrane module of the first stage membrane module unit 100a are connected by a pipe 88 via a pump 18. There is. The first space outlet of each membrane module of the first stage membrane module unit 100a and the first space inlet and the second space inlet of each membrane module of the second stage membrane module unit 100b are connected by a pipe 90. The first space outlet of each membrane module of the second stage membrane module unit 100b and the first space inlet and the second space inlet of each membrane module of the third stage membrane module unit 100c are connected by a pipe 94. The first space outlet of each membrane module of the third-stage membrane module unit 100c and the first space inlet and the second space inlet of each membrane module of the fourth-stage membrane module unit 100d are connected by a pipe 98. The first space outlet of each membrane module of the fourth-stage membrane module unit 100d and the inlet of the concentrating water tank 86 are connected by a pipe 104. A pipe 92 is connected to the second space outlet of each membrane module of the first stage membrane module unit 100a, and a pipe 96 is connected to the second space outlet of each membrane module of the second stage membrane module unit 100b. A pipe 102 is connected to the second space outlet of each membrane module of the third stage membrane module unit 100c, and a pipe 106 is connected to the second space outlet of each membrane module of the fourth stage membrane module unit 100d. The pipes 96, 102, 106 may join the pipe 92.

The concentrator 6 uses a multi-stage membrane module unit including a membrane module 10 having a first space 14 and a second space 16 partitioned by a semipermeable membrane 12, and each membrane module of the first-stage membrane module unit is used. The water to be treated is supplied to the first space and the second space, and the concentrated water is sequentially supplied to the first space and the second space of each membrane module of the membrane module unit of the next stage, and the first membrane module of each stage is supplied. It is a device that concentrates water by pressurizing the space 14 so that the water contained in the first space 14 is permeated into the second space 16 via the semipermeable membrane 12. That is, in the concentrating device 3, 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 concentrator 6, the water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion is passed through the pipe 88 from the water tank 84 to be treated by the pump 18 to the first stage membrane module unit 100a. The liquid is sent to the first space 14 and the second space 16 of each membrane module. In each membrane module of the first-stage membrane module unit 100a, the first space 14a is pressurized and the water contained in the first space 14 is permeated into the second space 16 via the semipermeable membrane 12 (concentration step). (1st stage)), diluted water is obtained in the second space 16 (dilution step (1st stage)). The diluted water obtained in the second space 16 of the first-stage membrane module 10 is stored in the diluted water tank as needed through the pipe 92, and then discharged to the outside of the system.

The concentrated water obtained in the first space 14 of each membrane module of the first-stage membrane module unit 100a passes through the pipe 90 to the first space 14 and the second space 16 of each membrane module of the second-stage membrane module unit 100b. The liquid is sent. In each membrane module of the second-stage membrane module unit 100b, the first space 14 is pressurized and the water contained in the first space 14 is permeated into the second space 16 via the semipermeable membrane 12 (concentration step). (2nd stage)), diluted water is obtained in the second space 16 (dilution step (2nd stage)). The diluted water obtained in the second space 16 of each membrane module of the second-stage membrane module unit 100b is stored in the diluted water tank as needed through the pipe 96, and then discharged to the outside of the system.

The concentrated water obtained in the first space 14 of each membrane module of the second-stage membrane module unit 100b passes through the pipe 94 to the first space 14 and the second space 16 of each membrane module of the third-stage membrane module unit 100c. The liquid is sent. In each membrane module of the third-stage membrane module unit 100c, the first space 14 is pressurized and the water contained in the first space 14 is permeated into the second space 16 via the semipermeable membrane 12 (concentration step). (Third stage)), diluted water is obtained in the second space 16 (dilution step (third stage)). The diluted water obtained in the second space 16 of each membrane module of the third-stage membrane module unit 100c is stored in the diluted water tank as needed through the pipe 102, and then discharged to the outside of the system.

The concentrated water obtained in the first space 14 of each membrane module of the third-stage membrane module unit 100c passes through the pipe 98 to the first space 14 and the second space 16 of each membrane module of the fourth-stage membrane module unit 100d. The liquid is sent. In each membrane module of the 4th stage membrane module unit 100d, the first space 14 is pressurized and the water contained in the first space 14 is permeated into the second space 16 via the semipermeable membrane 12 (concentration step). (4th stage)), diluted water is obtained in the second space 16 (dilution step (4th stage)). The concentrated water obtained in the first space 14 of each membrane module of the fourth-stage membrane module unit 100d is stored in the concentrated water tank 86 as needed through the pipe 104, and then discharged to the outside of the system. The diluted water obtained in the second space 16 of each membrane module of the fourth-stage membrane module unit 100d is stored in the diluted water tank as needed through the pipe 106, and then discharged to the outside of the system.

Here, the pump 18, the pipes 88, 90, 94, 98, etc. have water or concentration to be treated in the first space 14 and the second space 16 of each membrane module of each stage of the membrane module units 100a, 100b, 100c, 100d. It functions as a supply means for supplying water.

The diluted water obtained in the second space 16 of each membrane module of the membrane module units 100a, 100b, 100c, and 100d of each stage may be discharged to the outside of the system, or may be sent to the diluted water tank as needed. After being stored in the system, it may be discharged to the outside of the system. At least a part of the diluted water may be returned to the water tank 84 to be treated and mixed with the water to be treated of the first stage membrane module unit 100a. Further treatment may be performed on at least a part of the diluted water.

As described above, the treated water (concentrated water in the final stage) in which ions such as sulfate ions are concentrated from the treated water containing sulfate ion and at least one of sodium ion and ammonium ion, which is the treatment target. , Diluted water (diluted water in each stage) is obtained, and the volume of the water to be treated is reduced.

The concentrator 7 shown in FIG. 7 uses a semipermeable membrane module connected in a plurality of stages having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane, and sulfuric acid is used. Water to be treated containing ions and at least one of sodium ion and ammonium ion is passed through the first space of the semipermeable membrane module of the first stage, and the first space is pressurized to remove the water contained in the water to be treated. Concentrated water is obtained by permeating the semipermeable membrane, and the concentrated water is further concentrated in the second space of the semipermeable membrane module of each stage while obtaining concentrated water using the semipermeable membrane modules of the next and subsequent stages. As a semipermeable membrane treatment means for obtaining diluted water by passing at least a part of water or at least a part of diluted water obtained from another semipermeable membrane module, for example, the first stage membrane module unit 100a, the second stage. A membrane module unit 100b, a third-stage membrane module unit 100c, and a fourth-stage membrane module unit 100d are provided. The first-stage membrane module unit 100a includes, for example, four membrane modules connected in parallel, and the second-stage membrane module unit 100b includes, for example, four membrane modules connected in parallel. The third-stage membrane module unit 100c includes, for example, two membrane modules connected in parallel, and the fourth-stage membrane module unit 100d includes, for example, two membrane modules connected in parallel. Each membrane module 10 has a first space 14 and a second space 16 partitioned by a semipermeable membrane 12. The concentrating device 7 may include a water tank 84 to be treated for storing water to be treated, and a concentrating water tank 86 for storing concentrated water from the fourth-stage membrane module unit 100d. The concentrating 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 processing.

In the concentrating device 7 of FIG. 7, the outlet of the water tank 84 to be treated and the first space inlet of each membrane module of the first stage membrane module unit 100a are connected by a pipe 108 via a pump 18. The first space outlet of each membrane module of the first-stage membrane module unit 100a and the first space inlet of each membrane module of the second-stage membrane module unit 100b are connected by a pipe 110. The first space outlet of each membrane module of the second stage membrane module unit 100b and the first space inlet of each membrane module of the third stage membrane module unit 100c are connected by a pipe 112. The first space outlet of each membrane module of the third-stage membrane module unit 100c and the first space inlet of each membrane module of the fourth-stage membrane module unit 100d are connected by a pipe 114. The first space outlet of each membrane module of the fourth-stage membrane module unit 100d and the inlet of the concentrating water tank 86 are connected by a pipe 116. The pipe 118 branched from the pipe 116 is connected to the second space inlet of each membrane module of the fourth stage membrane module unit 100d. The second space outlet of each membrane module of the fourth stage membrane module unit 100d and the second space inlet of each membrane module of the third stage membrane module unit 100c are connected by a pipe 120. The second space outlet of each membrane module of the third-stage membrane module unit 100c and the second space inlet of each membrane module of the second-stage membrane module unit 100b are connected by a pipe 122. The second space outlet of each membrane module of the second stage membrane module unit 100b and the second space inlet of each membrane module of the first stage membrane module unit 100a are connected by a pipe 124. A pipe 126 is connected to the second space outlet of each membrane module of the first-stage membrane module unit 100a.

The concentrator 7 uses a multi-stage membrane module unit including a membrane module 10 having a first space 14 and a second space 16 partitioned by a semi-permeable membrane 12, and each membrane module of the first-stage membrane module unit is used. Water to be treated is supplied to the first space, and the concentrated water is sequentially passed through the first space of each membrane module of the next-stage membrane module unit in series to concentrate each membrane module of the final-stage membrane module unit. At least a part of the water is supplied to its own second space, and the obtained diluted water is passed in series to the second space 16 of each membrane module of the membrane module unit in the previous stage, and the first space 14 in each stage is passed. Is a device for concentrating water by allowing water contained in the first space 14 to permeate through the semi-permeable membrane 12 into the second space 16 by pressurizing. That is, in the concentrating device 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 concentrator 7, the water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion is passed through the pipe 108 from the water tank 84 to be treated by the pump 18 to the first stage membrane module unit 100a. The liquid is sent to the first space 14 of each membrane module. On the other hand, the second space 16 of each film module of the fourth-stage film module unit 100d, which will be described later, the second space 16 of each film module of the third-stage film module unit 100c, and each film module of the second-stage film module unit 100b. The diluted water sent through the second space 16 is sent to the second space 16 of each membrane module of the first stage membrane module unit 100a through the pipe 124. In each membrane module of the first-stage membrane module unit 100a, the first space 14 is pressurized and the water contained in the first space 14 is permeated into the second space 16 via the semipermeable membrane 12 (concentration step). (1st stage)), diluted water is obtained in the second space 16 (dilution step (1st stage)). The concentrated water obtained in the first space 14 of each membrane module of the first-stage membrane module unit 100a is sent to the first space 14 of each membrane module of the second-stage membrane module unit 100b through the pipe 110. The diluted water obtained in the second space 16 of each membrane module of the first-stage membrane module unit 100a is discharged to the outside of the system through the pipe 126.

In each membrane module of the second-stage membrane module unit 100b, the second space 16 of each membrane module of the fourth-stage membrane module unit 100d, which will be described later, is passed through the second space 16 of each membrane module of the third-stage membrane module unit 100c. The diluted water that has been sent is sent to the second space 16 of each membrane module of the second-stage membrane module unit 100b through the pipe 122. The first space 14 is pressurized and the water contained in the first space 14 is permeated into the second space 16 via the semipermeable membrane 12 (concentration step (second stage)), and in the second space 16. Diluted water is obtained (dilution step (second stage)). The concentrated water obtained in the first space 14 of each membrane module of the second-stage membrane module unit 100b is sent to the first space 14 of each membrane module of the third-stage membrane module unit 100c through the pipe 112. The diluted water obtained in the second space 16 of each membrane module of the second-stage membrane module unit 100b is sent to the second space 16 of each membrane module of the first-stage membrane module unit 100a through the pipe 124.

In each membrane module of the third-stage membrane module unit 100c, the diluted water sent through the second space 16 of each membrane module of the fourth-stage membrane module unit 100d, which will be described later, passes through the pipe 120 and the third-stage membrane. The liquid is sent to the second space 16 of each membrane module of the module unit 100c. The first space 14 is pressurized and the water contained in the first space 14 is permeated into the second space 16 via the semipermeable membrane 12 (concentration step (third stage)), and in the second space 16. Diluted water is obtained (dilution step (third stage)). The concentrated water obtained in the first space 14 of each membrane module of the third-stage membrane module unit 100c is sent to the first space 14 of each membrane module of the fourth-stage membrane module unit 100d through the pipe 114. The diluted water obtained in the second space 16 of each membrane module of the third-stage membrane module unit 100c is sent to the second space 16 of each membrane module of the second-stage membrane module unit 100b through the pipe 122.

In each membrane module of the 4th stage membrane module unit 100d, the concentrated water obtained in the first space 14 of each membrane module of the 4th stage membrane module unit 100d flows to the second space 16 through the pipes 116 and 118 as shown below. The liquid is sent. The first space 14 is pressurized and the water contained in the first space 14 is permeated into the second space 16 via the semipermeable membrane 12 (concentration step (fourth stage)), and in the second space 16. Diluted water is obtained (dilution step (4th step)). The concentrated water obtained in the first space 14 of each membrane module of the fourth-stage membrane module unit 100d is stored in the concentrated water tank 86 as needed through the pipe 116, and then discharged to the outside of the system, and is discharged from the pipe 116. The branched concentrated water is sent to the second space 16 of each membrane module of the fourth-stage membrane module unit 100d through the pipe 118. The diluted water obtained in the second space 16 of each membrane module of the fourth-stage membrane module unit 100d is sent to the second space 16 of each membrane module of the third-stage membrane module unit 100c through the pipe 120.

Here, the pump 18, the pipes 108, 110, 112, 114, 116, 118, 120, 122, 124 and the like are the first space 14 of each membrane module of each stage of the membrane module units 100a, 100b, 100c, 100d. It functions as a supply means for supplying water to be treated, concentrated water, or diluted water to the second space 16.

The diluted water obtained in the second space 16 of each membrane module of the membrane module unit 100a may be discharged to the outside of the system, or if necessary, liquid is sent to the diluted water tank and stored, and then to the outside of the system. It may be discharged. At least a part of the diluted water may be returned to the water tank 84 to be treated and mixed with the water to be treated of the first stage membrane module unit 100a. Further treatment may be performed on at least a part of the diluted water.

As described above, the treated water (concentrated water in the final stage) in which ions such as sulfate ions are concentrated from the treated water containing sulfate ion and at least one of sodium ion and ammonium ion, which is the treatment target. , Diluted water (diluted water in the final stage) is obtained, and the volume of the water to be treated is reduced.

When water to be treated is supplied to each membrane module of the first-stage membrane module unit 100a, for example, a pressure of 7 MPa or less is applied, and the water to be treated is supplied to the subsequent membrane module unit of the first-stage membrane module unit 100a. This may be done by the pressure applied to each membrane module. The inlet pressure of the first space 14 in each film module is preferably in the range of 7 MPa or less, the inlet pressure of the second space 16 is preferably smaller than the inlet pressure of the first space 14, and the second It is more preferable that the inlet pressure of the space 16 is 50% or less of the inlet pressure of the first space 14. This can reduce the risk of damage to the semipermeable membrane due to pressure.

It is preferable that the flow rate on the first space 14 side in each membrane module 10 is larger than the flow rate on the second space 16 side. If the flow rate on the first space 14 side is equal to or less than the flow rate on the second space 16 side, the flow rate on the first space 14 side of the subsequent membrane module may be insufficient. For example, the pump 18 or the like functions as a flow rate adjusting means for making the flow rate in the first space larger than the flow rate in the second space.

If the permeation flux is too large, the concentration difference becomes large, which may cause problems such as an increase in fouling risk and an excessively high pressure. Further, if the permeation flux is too small, the concentration efficiency may deteriorate. From these points, the permeation flux of each membrane module 10 is preferably in the range of 0.005 m / d to 0.05 m / d, and preferably in the range of 0.015 m / d to 0.04 m / d. Is more preferable. For example, the pump 18 or the like functions as a permeation flux adjusting means for controlling the permeation flux within the above range.

The water to be treated to be passed through each membrane module of the first-stage membrane module unit 100a has a sulfate ion concentration of 20000 mg / L or more, and at least one of sodium ion and ammonium ion has a concentration of 10000 mg / L or more. In this case, the concentrated water discharged from the first space 14 side of each membrane module of the final stage membrane module unit preferably has a concentration of 25% by weight or more as ammonium sulfate or sodium sulfate, and has a concentration of 30% by weight or more. Is more preferable.

A valve may be installed in at least one of the pipes, and the position and number of valves installed are not particularly limited. Further, a flow meter may be installed as a flow rate measuring means for measuring the flow rate, and a pressure gauge may be installed as a pressure measuring means for measuring the pressure in at least one of the pipes.

Further, FIGS. 6 and 7 are examples of the apparatus configuration, and the number of stages, the number of parallel membrane modules, the arrangement, the supply method of the supplied water, and the like may be appropriately changed.

When a multi-stage membrane module such as the concentrators 3, 4, 5, 6 and 7 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.

When a membrane module unit having a plurality of membrane modules connected in parallel is used as the membrane module of each stage as in the concentrators 6 and 7, the number of membrane modules in each membrane module unit is the number of membrane modules to be treated. It may be decided according to the flow rate and the like.

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.

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.

Examples of the shape of the semipermeable membrane 12 include a flat membrane, a hollow fiber membrane, and a spiral membrane. A hollow fiber membrane is preferable because the surface area of the semipermeable membrane can be increased.

The water to be treated may be water containing at least one of sulfate ion, sodium ion and ammonium ion, and is not particularly limited. For example, wastewater discharged from a semiconductor factory, wastewater discharged from a chemical factory, etc. Can be mentioned.

<Water treatment method and water treatment equipment>
A water treatment method including the above concentrating method and a water treatment apparatus having the above concentrating device will be described.

The water treatment method according to the present embodiment includes the above concentration method, and for example, at least one of a reverse osmosis membrane treatment step, a coagulation sedimentation treatment step, an organic substance removal treatment step, and a pH adjustment step is preceded by the semipermeable membrane treatment step. It may include one pretreatment step.

Further, the water treatment method according to the present embodiment includes the above-mentioned concentration method, for example, in the latter stage of the semipermeable membrane treatment step, sulfate ions and ammonium ions are converted into ammonium sulfate crystals from the concentrated water obtained in the semipermeable membrane treatment step. It may include at least one post-treatment step of the recovery step of recovering sulfate ions and sodium ions as crystals of sodium sulfate from the concentrated water obtained in the semipermeable membrane treatment step.

The water treatment apparatus according to the present embodiment includes the above-mentioned concentrator, for example, a reverse osmosis membrane treatment means, a coagulation sedimentation treatment means, an organic substance removal treatment means, and a pH adjusting means provided in front of the semipermeable membrane treatment means. It may be provided with at least one pretreatment means.

Further, the water treatment apparatus according to the present embodiment is a recovery means for recovering sulfate ions and ammonium ions as ammonium sulfate crystals from the concentrated water obtained by the semipermeable membrane treatment means, for example, after the semipermeable membrane treatment means. Further, at least one post-treatment means may be provided among the recovery means for recovering sulfate ions and sodium ions as crystals of sodium sulfate from the concentrated water obtained by the semipermeable membrane treatment means.

An outline of an example of a water treatment device having the above-mentioned concentrating device according to the embodiment of the present invention is shown in FIG. 8, and the configuration thereof will be described.

The water treatment device 8 shown in FIG. 8 is, for example, a device for treating wastewater containing at least one of sulfate ion, sodium ion and ammonium ion discharged from a semiconductor factory or the like, and among the above-mentioned enrichment devices 1 to 7. As a reverse osmosis membrane treatment means for obtaining RO concentrated water and RO permeable water by reverse osmosis membrane treatment of wastewater, a reverse osmosis membrane treatment device 200, a storage tank 202 for storing RO concentrated water, and To prepare for. Further, as a water recovery means for recovering water from the diluted water obtained by the concentrators 1 to 7, obtained by the water recovery device 204 and the concentrators 1 to 7 in the subsequent stage of any one of the concentrators 1 to 7. A recovery device 206 is provided as a recovery means for recovering sulfate ions and ammonium ions as crystals of ammonium sulfate from the concentrated water to be collected, or as recovery means for recovering sulfate ions and sodium ions as crystals of sodium sulfate.

In the water treatment device 8, the RO concentrated water outlet and the storage tank 202 of the reverse osmosis membrane treatment device 200, the storage tank 202 and the concentrating devices 1 to 7, the diluted water outlet of the concentrating devices 1 to 7, the water recovery device 204, and the concentrating device 1 The concentrated water outlets of 7 to 7 and the recovery device 206 are each connected by a pipe or the like.

For example, wastewater containing sulfate ion, sodium ion, and ammonium ion discharged from a semiconductor factory or the like is subjected to reverse osmosis membrane treatment using a reverse osmosis membrane in the reverse osmosis membrane treatment apparatus 200 to concentrate RO. Water and RO permeated water can be obtained (reverse osmosis membrane treatment step). The RO concentrated water obtained by the reverse osmosis membrane treatment is stored in the storage tank 202 as needed, and then becomes the water to be treated by the concentrating devices 1 to 7 provided with the semipermeable membrane module. Depending on the properties of the water to be treated, organic matter removal treatment means may be provided to remove organic matter, a pH adjustment device may be provided to adjust the pH, or a solid-liquid separation device or particulate matter may be provided in the preceding stage of the concentrators 1 to 7. A filter or the like may be provided as the removing means.

In any of the concentrating devices 1 to 7, as described above, the concentration treatment is performed, and the treated water containing at least one of sulfate ion, sodium ion and ammonium ion, which is the treatment target, has ions such as sulfate ion. The treated water (concentrated water) and the diluted water are obtained, and the volume of the water to be treated is reduced.

The diluted water discharged from the concentrators 1 to 7 may be recovered by installing a water recovery device 204 after the concentrators 1 to 7 (water recovery step). For the concentrated water discharged from the concentrators 1 to 7, a recovery device 206 such as an evaporator is installed after the concentrators 1 to 7 to further concentrate the concentrated water and recover ammonium sulfate, sodium sulfate and the like. May be good (collection process). In that case, the recovered water (evaporated water) obtained by the recovery device may be returned to the front stage of the concentration devices 1 to 7, and evaporates to the front stage of the concentration devices 1 to 7 using a semipermeable membrane module capable of reducing the osmotic pressure difference. Returning the water is not a disadvantage.

Examples of the organic substance removing treatment means include an oxidizing device by adding an oxidizing agent, and the like, in addition to the activated carbon treatment device. Examples of the activated carbon treatment apparatus include an activated carbon tower filled with activated carbon.

The pH adjusting device is provided with, for example, a pH adjusting tank, and a pH adjusting agent is added to adjust the pH. Examples of the pH adjuster include acids such as hydrochloric acid and sulfuric acid, and alkalis such as sodium hydroxide.

The reverse osmosis membrane treatment apparatus 200 performs reverse osmosis membrane treatment using a reverse osmosis membrane to obtain RO concentrated water and RO permeated water.

Examples of the particulate matter removing means include a precipitation device by a precipitation method, a pressure levitation device by a pressure levitation method, and the like, in addition to the filter. Examples of the filter include a microfiltration membrane (MF membrane), an ultrafiltration membrane (UF membrane) and the like.

The coagulation sedimentation treatment means may be provided in front of the concentrators 1 to 7. As the coagulation-precipitation treatment means, for example, a suspending substance or the like is coagulated using a coagulant such as an inorganic coagulant or a polymer coagulant to form flocs, and solid-liquid separation is performed. The coagulation sedimentation treatment apparatus includes, for example, a coagulation tank, a floc forming tank, a settling tank and the like.

The configuration of the concentrator is, for example, the configuration of the concentrators 1 to 7, and the configuration and method of the semipermeable membrane module may be determined according to the quality of the water to be treated and the purity of the recovered ammonium sulfate and the like.

The water to be treated to be passed through the concentrators 1 to 7 has a sulfate ion concentration of 20000 mg / L or more, and at least one of sodium ion and ammonium ion has a concentration of 10000 mg / L or more.

The water recovery means recovers water from diluted water. Examples of the water recovery device 204 include a reverse osmosis membrane treatment device, an electrodialysis device, and the like.

The recovery means is to recover sulfate ions and ammonium ions from concentrated water as crystals of ammonium sulfate, or to recover sulfate ions and sodium ions from concentrated water as crystals of sodium sulfate. Examples of the recovery device 206 include an evaporation device such as an evaporator, a membrane distillation device, a crystallization device, a solid-liquid separation device, and the like.

By the water treatment method and the water treatment apparatus according to the present embodiment, it is possible to concentrate the water to be treated containing sulfate ion, sodium ion and at least one of ammonium ion at a high concentration discharged from a semiconductor factory or the like at low cost. , The amount of waste liquid with high ion concentration can be reduced.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

<Example 1>
The test solution prepared by adding ammonium sulfate to pure water was used as water to be treated, and the concentration treatment was performed using the concentration device 1 shown in FIG. The amount of ammonium sulfate added (% by weight) in the water to be treated is changed, the water to be treated is supplied to the inlets of the first space and the inlet of the second space of the membrane module, respectively, and the concentrated water and diluted water are returned to the water to be treated. The circulation operation was performed. At that time, the operation was performed so that the flow rate at the entrance of the second space was 30 L / h and the flow rate at the exit of the first space was 120 L / h. The ammonium sulfate concentrations of the water to be treated, the concentrated water, and the diluted water were measured using an ion chromatograph (manufactured by Thermo Fisher Scientific). As the semipermeable membrane module, a membrane module manufactured by Toyobo Co., Ltd .: a 5-inch membrane manufactured by Toyobo Co., Ltd. (working pressure range ≤ 7 MPa) was used. The results are shown in Table 1.

<Comparative Example 1>
The test solution prepared by adding ammonium sulfate to pure water was used as water to be treated, and the concentration treatment was performed using the concentration device 1 shown in FIG. The amount of ammonium sulfate added to the water to be treated is changed, and the water to be treated is supplied to the inlet of the first space of the membrane module by a pump, and concentrated water and diluted water are used as the water to be treated without being supplied to the inlet of the second space. A circular operation was performed to return the product. At that time, the operation was performed so that the flow rate at the outlet of the first space was 120 L / h. The ammonium sulfate concentrations of the water to be treated, the concentrated water, and the diluted water were measured using an ion chromatograph. As the semipermeable membrane module, a membrane module manufactured by Toyobo Co., Ltd .: a 5-inch membrane manufactured by Toyobo Co., Ltd. (working pressure range ≤ 7 MPa) was used. The results are shown in Table 1.

As shown in Table 1, in Comparative Example 1, the operating pressure increases as the concentration of ammonium sulfate in the treated water increases, and the treated water having a concentration of ammonium sulfate of 20% by weight or more operates within the working pressure range of the membrane. Couldn't. In Example 1, even if the concentration of ammonium sulfate in the water to be treated was 27% by weight, the operation could be performed within the working pressure range of the membrane.

<Examples 2 and 3>
The test solution prepared by adding ammonium sulfate to pure water was used as water to be treated, and the concentration treatment was performed using the concentration device 1 shown in FIG. A circulation operation was performed in which the water to be treated was supplied to the inlet of the first space and the inlet of the second space of the membrane module by a pump, and the concentrated water and the diluted water were returned to the water to be treated. At that time, the flow rate at the inlet of the second space was set to 30 L / h, and the flow rate at the outlet of the first space was set to 120 L / h, which is the minimum flow rate of the concentrated water of the semipermeable membrane module used. The ammonium sulfate concentrations of the water to be treated, the concentrated water, and the diluted water were measured using an ion chromatograph. The test was carried out at two concentrations of ammonium sulfate in the water to be treated. The results of Example 2 in which a 3 wt% ammonium sulfate solution was used as the treated water are shown in Table 2, and a 6 wt% ammonium sulfate solution was used as the treated water. The results of Example 3 are shown in Table 3. The results showed the permeated flux (= permeated water flow rate / membrane area) [m / d] and the concentration ratio per unit module (concentrated water concentration / treated water concentration) [times / line]. The permeated water flow rate required for calculating the permeated flux was obtained from the difference between the flow rate at the second space outlet and the flow rate at the second space inlet. As the semipermeable membrane module, a membrane module manufactured by Toyobo Co., Ltd .: a 5-inch membrane manufactured by Toyobo Co., Ltd. (working pressure range ≤ 7 MPa) was used.

As shown in Table 2, it can be seen that when the permeation flux is 0.005 m / d or less, it can be concentrated only slightly. Further, when the permeation flux is 0.05 m / d or more, the concentration is 2.0 times or more only in one stage of the semipermeable membrane module, and there is a concern that the fouling risk increases. Further, according to the result of the operating pressure at the time of the experiment, 5.8 MPa is required when the permeation flux is 0.07 m / d.

As shown in Table 3, it can be seen that, as in the results of Table 2, when the permeation flux is 0.005 m / d or less, it can be concentrated only slightly. When the permeation flux is 0.07 m / d or more, the pressure resistance limit of the membrane is reached at a concentration of ammonium sulfate of 6% by weight in the treated water.

From the above results, it can be seen that the permeation flux is preferably in the range of 0.005 to 0.05 m / d.

As described above, according to the method of the example, the water to be treated containing sulfate ion and at least one of sodium ion and ammonium ion at a high concentration can be concentrated at low cost, and the amount of waste liquid having a high ion concentration can be reduced. I found that I could do it.

1,2,3,4,5,6,7 Concentrator, 8 Water treatment equipment, 10,10a, 10b, 10c Membrane module, 12,12a, 12b, 12c Semipermeable membrane, 14, 14a, 14b, 14c No. One space, 16, 16a, 16b, 16c Second space, 18 pumps, 20 inverters, 22, 22a, 22b, 22c, 23, 32, 32a, 32b, 32c valves, 24, 26, 28, 30, 34, 36 , 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 88, 90, 92, 94, 96 , 98, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126 Piping, 60a, 60b, 60c, 62a, 62b, 62c Diluted water tank, 84 Water tank to be treated, 86 Concentrated water tank, 100a, 100b, 100c, 100d membrane module unit, 200 reverse osmosis membrane treatment device, 202 storage tank, 204 water recovery device, 206 recovery device.

Claims (12)

Using a semi-transparent module having a first space and a second space partitioned by a semi-transparent film, water to be treated is passed through the first space, and the first space is pressurized to press the water to be treated. Concentrated water is obtained by allowing the water contained in the water 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 to obtain diluted water. Including semi-transparent film treatment step
The concentration method of the water to be treated, characterized in that the sulfate ion concentration is 20000 mg / L or more, and the concentration of at least one of sodium ion and ammonium ion is 10,000 mg / L or more. Using a semipermeable membrane module connected in multiple stages, which has a first space and a second space partitioned by a semipermeable membrane, water to be treated is passed through the first space of the semipermeable membrane module in the first stage. Concentrated water is obtained by watering 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 passed through the semipermeable membrane modules of the next and subsequent stages. In addition to obtaining concentrated water, in the second space of the semipermeable membrane module of each stage, at least one of the part of the water to be treated, at least a part of the concentrated water, or the diluted water obtained from the other semipermeable membrane module. Including a semipermeable membrane treatment step of passing water through the section to obtain diluted water,
The concentration method of the water to be treated, characterized in that the sulfate ion concentration is 20000 mg / L or more, and the concentration of at least one of sodium ion and ammonium ion is 10,000 mg / L or more. The concentration method according to claim 1 or 2.
A concentration method comprising a permeation flux of the semipermeable membrane module in the range of 0.005 m / d to 0.05 m / d. The concentration method according to any one of claims 1 to 3.
A concentration method characterized in that the flow rate in the first space is made larger than the flow rate in the second space. Using a semi-transparent module having a first space and a second space partitioned by a semi-transparent film, water to be treated is passed through the first space, and the first space is pressurized to press the water to be treated. Concentrated water is obtained by allowing the water contained in the water 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 to obtain diluted water. Equipped with semi-transparent film treatment means,
The water to be treated is a concentrator having a sulfate ion concentration of 20000 mg / L or more and a concentration of at least one of sodium ion and ammonium ion of 10000 mg / L or more. Using a semipermeable membrane module connected in multiple stages, which has a first space and a second space partitioned by a semipermeable membrane, water to be treated is passed through the first space of the semipermeable membrane module in the first stage. Concentrated water is obtained by watering 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 passed through the semipermeable membrane modules of the next and subsequent stages. In addition to obtaining concentrated water, in the second space of the semipermeable membrane module of each stage, at least one of the part of the water to be treated, at least a part of the concentrated water, or the diluted water obtained from the other semipermeable membrane module. Equipped with a semipermeable membrane treatment means to obtain diluted water by passing water through the part,
The water to be treated is a concentrator having a sulfate ion concentration of 20000 mg / L or more and a concentration of at least one of sodium ion and ammonium ion of 10000 mg / L or more. The concentrator according to claim 5 or 6, wherein the concentrator
A concentrator further comprising a permeation flux adjusting means for setting the permeation flux of the semipermeable membrane module in the range of 0.005 m / d to 0.05 m / d. The concentrator according to any one of claims 5 to 7.
A concentrator further comprising a flow rate adjusting means for making the flow rate in the first space larger than the flow rate in the second space. The concentration method according to any one of claims 1 to 4 is included.
A water treatment method comprising a reverse osmosis membrane treatment step in front of the semipermeable membrane treatment step. The water treatment method according to claim 9.
Following the semipermeable membrane treatment step, a recovery step of recovering sulfate ions and ammonium ions as ammonium sulfate crystals from the concentrated water obtained in the semipermeable membrane treatment step, and a recovery step of recovering sulfate ions and sodium ions from sodium sulfate. A water treatment method comprising at least one post-treatment step among the recovery steps of recovering as a crystal. The concentrator according to any one of claims 5 to 8, and the concentrator.
The reverse osmosis membrane treatment means provided in front of the semipermeable membrane treatment means and
A water treatment device characterized by being provided with. The water treatment apparatus according to claim 11.
After the semipermeable membrane treatment means, a recovery means for recovering sulfate ions and ammonium ions as ammonium sulfate crystals from the concentrated water obtained by the semipermeable membrane treatment means, and sulfate ions and sodium ions for sodium sulfate. A water treatment apparatus comprising at least one post-treatment means among the recovery means for recovering as a crystal.

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