CN115432876B

CN115432876B - Water treatment method and water treatment device

Info

Publication number: CN115432876B
Application number: CN202210548016.0A
Authority: CN
Inventors: 若山圣; 中野徹; 高田明广
Original assignee: Organo Corp
Current assignee: Organo Corp
Priority date: 2021-06-04
Filing date: 2022-05-18
Publication date: 2024-04-09
Anticipated expiration: 2042-05-18
Also published as: TW202313490A; CN115432876A; JP2022186382A

Abstract

The present invention provides a water treatment method and a water treatment device capable of recovering ammonia from water containing ammonia and further recovering valuable substances and water from drainage after removal of the recovered substances. A water treatment process for recovering valuable substances from water containing ammonia, comprising: a first recovery step of recovering at least one of ammonia and ammonium ions from water containing ammonia as a first recovered product by a distillation apparatus (11); and a second recovery step of introducing distilled water from the distillation apparatus (11) into the first space (14) by using a semipermeable membrane module (10) having the first space (14) and the second space (16) partitioned by the semipermeable membrane (12), pressurizing the first space (14) to allow water contained in the distilled water to permeate the semipermeable membrane (12), thereby obtaining a second recovered product as concentrated water, and introducing water into the second space (16) to distill a part of the treated water or at least a part of the concentrated water, thereby obtaining diluted water.

Description

Water treatment method and water treatment device

Technical Field

The present invention relates to a water treatment method and a water treatment apparatus for recovering valuable substances from water containing ammonia.

Background

In recent years, as a method for recovering valuable substances in wastewater from factories and the like, there are a reverse osmosis method for recovering permeate water using a reverse osmosis membrane to reduce the amount of water, a membrane distillation method using a gas permeable membrane, and the like.

Further, as in patent document 1, the following method is known: the water to be treated or the concentrated water thereof is passed through a first space and a second space partitioned by a semipermeable membrane of a semipermeable membrane module, and the first space is pressurized, whereby the water is concentrated. The concentration method using such a semipermeable membrane can concentrate the wastewater to a high concentration with less energy consumption by reducing the concentration difference (osmotic pressure difference) between the first space and the second space as compared with the general reverse osmosis method.

As in patent document 2, there is also known a method of recovering ammonia as a gas from ammonia-containing water containing ammonia by a distillation apparatus. In the case of using a distillation method, a large amount of effluent from which ammonia as a recovered product is removed is produced. In addition, the concentration of soluble solid components (TDS) such as inorganic salts in the drainage becomes high, and the drainage is not suitable for reuse. Thus, the drainage produced by distillation is discharged directly or after further treatment.

Therefore, a method is demanded which can recover ammonia from water containing ammonia and further recover valuable substances and water from the drainage water from which the recovered substances have been removed and reuse the recovered substances.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2018-069198

Patent document 2: japanese patent laid-open publication No. 2019-098205

Disclosure of Invention

Problems to be solved by the invention

The present invention aims to provide a water treatment method and a water treatment device, which can recover ammonia from water containing ammonia and further recover valuable substances and water from drainage after the recovery substances are removed.

Means for solving the problems

The invention provides a water treatment method for recovering valuable substances from water containing ammonia, comprising the following steps: a first recovery step of recovering at least one of ammonia and ammonium ions from the ammonia-containing water by a distillation apparatus as a first recovered product; and a second recovery step of introducing distilled water from the distillation apparatus into the first space by using a semipermeable membrane module having the first space and the second space partitioned by a semipermeable membrane, pressurizing the first space, allowing water contained in the distilled water to permeate the semipermeable membrane, thereby obtaining a second recovered product as concentrated water, and introducing a part of the distilled water or at least a part of the concentrated water into the second space, thereby obtaining diluted water.

The invention provides a water treatment method for recovering valuable substances from water containing ammonia, comprising the following steps: a first recovery step of recovering at least one of ammonia and ammonium ions from the ammonia-containing water by a distillation apparatus as a first recovered product; and a second recovery step of pressurizing the first space of the semipermeable membrane module having a first space and a second space separated by a semipermeable membrane by passing distilled water from the distillation apparatus through the first space of the semipermeable membrane module of the 1 st stage, allowing water contained in the distilled water to permeate the semipermeable membrane, thereby obtaining concentrated water, further using the semipermeable membrane module of the subsequent stage for the concentrated water to obtain a second recovered product as concentrated water, and passing a part of the distilled water or at least a part of the concentrated water or at least a part of the dilution water obtained from the other semipermeable membrane module to the second space of the semipermeable membrane module of each stage to obtain diluted water.

The water treatment method preferably further comprises the steps of: a water recovery step of passing at least a part of the dilution water discharged from the second recovery step to a reverse osmosis membrane after the second recovery step to obtain permeate water; and a return step of returning the concentrated water discharged from the reverse osmosis membrane to a front stage of the semipermeable membrane module.

In the water treatment method, the concentration of sulfate ions in the ammonia-containing water is preferably 6000mg/L or more and the concentration of ammonium ions is preferably 2000mg/L or more.

The present invention provides a water treatment device for recovering valuable substances from water containing ammonia, comprising: a first recovery unit that recovers at least one of ammonia and ammonium ions from the ammonia-containing water as a first recovery product by a distillation device; and a second recovery unit that uses a semipermeable membrane module having a first space and a second space partitioned by a semipermeable membrane, and that passes distilled water from the distillation apparatus through the first space, pressurizes the first space, and causes water contained in the distilled water to permeate the semipermeable membrane, thereby obtaining a second recovered product as concentrated water, and passes a part of the distilled water or at least a part of the concentrated water to the second space, thereby obtaining diluted water.

The present invention provides a water treatment device for recovering valuable substances from water containing ammonia, comprising: a first recovery unit that recovers at least one of ammonia and ammonium ions from the ammonia-containing water as a first recovery product by a distillation device; and a second recovery unit that uses a semipermeable membrane module having a first space and a second space separated by a semipermeable membrane and connected in multiple stages, pressurizes the first space by passing distilled water from the distillation apparatus through the first space of the semipermeable membrane module of the 1 st stage, and causes water contained in the distilled water to permeate the semipermeable membrane, thereby obtaining concentrated water, and further uses the semipermeable membrane module of the subsequent stage for the concentrated water to obtain a second recovery product as concentrated water, and passes a part of the distilled water or at least a part of the concentrated water or at least a part of the dilution water obtained from the other semipermeable membrane module to the second space of the semipermeable membrane module of each stage to obtain diluted water.

The water treatment apparatus preferably further includes: a water recovery unit that, after the second recovery unit, passes at least a part of the dilution water discharged from the second recovery unit to a reverse osmosis membrane to obtain permeate water; and a return unit that returns the concentrated water discharged from the reverse osmosis membrane to the front stage of the semipermeable membrane module.

In the water treatment apparatus, the concentration of sulfate ions in the ammonia-containing water is preferably 6000mg/L or more and the concentration of ammonium ions is preferably 2000mg/L or more.

Effects of the invention

According to the present invention, it is possible to provide a water treatment method and a water treatment apparatus capable of recovering ammonia from water containing ammonia and further recovering valuable substances and water from drainage after removal of the recovered substances.

Drawings

Fig. 1 is a schematic configuration diagram showing an example of a water treatment apparatus according to an embodiment of the present invention.

Fig. 2 is a schematic configuration diagram showing another example of the water treatment apparatus according to the embodiment of the present invention.

Fig. 3 is a schematic configuration diagram showing another example of the water treatment apparatus according to the embodiment of the present invention.

Fig. 4 is a schematic configuration diagram showing another example of the water treatment apparatus according to the embodiment of the present invention.

Fig. 5 is a schematic configuration diagram showing another example of the water treatment apparatus according to the embodiment of the present invention.

Fig. 6 is a schematic configuration diagram showing another example of the water treatment apparatus according to the embodiment of the present invention.

Fig. 7 is a schematic configuration diagram showing another example of the water treatment apparatus according to the embodiment of the present invention.

FIG. 8 is a schematic configuration diagram showing another example of a water treatment apparatus according to an embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described. The present embodiment is an example of the implementation of the present invention, and the present invention is not limited to the present embodiment.

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

The water treatment apparatus 1 shown in fig. 1 is an apparatus for recovering valuable substances from water containing ammonia. The water treatment apparatus 1 includes a distillation apparatus 11 as a first recovery unit for recovering at least one of ammonia and ammonium ions from water containing ammonia as a first recovery product, and a membrane module 10 as a second recovery unit for introducing distilled water from the distillation apparatus 11 into the first space 14, pressurizing the first space 14, and allowing water contained in the distilled water to permeate the semipermeable membrane 12 to obtain a second recovery product as concentrated water, and introducing a part of the distilled water into the second space 16 to obtain dilution water, using a semipermeable membrane module having a first space (concentrate side) 14 and a second space (permeate side) 16 partitioned by the semipermeable membrane 12. The water treatment apparatus 1 may be provided with a distillation treatment water tank for storing distilled treatment water between the distillation apparatus 11 and the membrane module 10.

In the water treatment apparatus 1 of fig. 1, a pipe 25 is connected to an inlet of the distillation apparatus 11. A pipe 27 is connected to the first recycle outlet of the distillation apparatus 11. The distilled water outlet of the distillation apparatus 11 is connected to the first space inlet of the membrane module 10 via a pipe 24 via a pump 18, and a pipe 26 branching from the pipe 24 on the downstream side of the pump 18 is connected to the second space inlet of the membrane module 10 via a valve 22. 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 pressurizing pump that sucks in distilled water and pressurizes and discharges the distilled water to the membrane module 10, and is driven at a rotational speed corresponding to the input driving frequency. The pump 18 is provided with an inverter 20 that outputs a driving frequency corresponding to an input command signal to the pump 18, for example. The valves 22 and 23 are, for example, valves whose opening/closing degree can be manually or automatically adjusted.

The membrane module 10 has a first space 14 and a second space 16 partitioned by the semipermeable membrane 12, and is configured to allow distilled water to pass through the first space 14 from a first space inlet of the membrane module 10, and to allow water to pass through the second space 16 from a second space inlet, thereby pressurizing the first space 14, and allowing water contained in the distilled water in the first space 14 to permeate through the semipermeable membrane 12 to the second space 16, thereby concentrating the water. That is, in the water treatment apparatus 1, the semipermeable membrane 12 is used to concentrate the distilled water. The membrane module 10 is a device that performs concentration treatment by supplying distilled water to both the first space 14 and the second space 16 of the membrane module 10.

In the water treatment apparatus 1, ammonia-containing water containing ammonia is supplied to the distillation apparatus 11 through a pipe 25. Distillation is performed in the distillation apparatus 11, and at least one of ammonia and ammonium ions is recovered from the ammonia-containing water as a first recovered product (first recovery step). The first recovered material is discharged through the pipe 27.

The distilled water obtained in the distillation apparatus 11 is pressurized and fed from the first space inlet of the membrane module 10 to the first space 14 by the pump 18 through the pipe 24 with the valve 23 opened. In addition, the distilled water is fed from the second space inlet of the membrane module 10 to the second space 16 through the pipe 26 branched from the pipe 24 in a state where the valve 22 is opened, and the water is introduced. A part of the water contained in the pressurized distilled water is transmitted from the first space 14 to the second space 16 through the semipermeable membrane 12. At this time, most of the ions and the like contained in the distilled water cannot pass through the semipermeable membrane 12, and therefore, the water in the first space 14 which does not pass through the semipermeable membrane 12 is concentrated. On the other hand, in the second space 16, a part of the distilled water supplied through the pipe 26 and the permeate hydration flow having a low ion concentration that has permeated the semipermeable membrane 12 exert a dilution effect. The concentrated water obtained in the first space 14 is discharged as a second recovered product from the first space outlet through a pipe 28, and the diluted water obtained in the second space 16 is discharged from the second space outlet through a pipe 30. Here, in the membrane module 10, the first space 14 is pressurized, and water contained in the distilled water in the first space 14 is permeated into the second space 16 through the semipermeable membrane 12, so that concentrated water (second recovered product) is obtained in the first space 14 (concentration step), and diluted water is obtained in the second space 16 (dilution step) (the above-described second recovery step).

Here, the pipes 24 and 26, the pump 18, and the like function as supply means for supplying distilled water to both the first space 14 and the second space 16 of the membrane module 10.

The dilution water obtained in the second space 16 may be discharged to the outside of the system through the pipe 30, or may be supplied to a dilution water tank and stored as needed, and then discharged to the outside of the system, or may be reused. At least a part of the dilution water may be fed to the distillation treatment water tank, and mixed with the distillation treatment water in the distillation treatment water tank. At least a part of the dilution water may be subjected to another treatment, for example, reverse osmosis membrane treatment as described below.

As described above, at least one of ammonia and ammonium ions is recovered as a first recovered product from ammonia-containing water that is the object of treatment, and further, concentrated water in which ions are concentrated is recovered as a second recovered product, thereby obtaining dilution water, and reducing the volume of the ammonia-containing water. In addition, the first recycle, the second recycle, and the dilution water can be reused.

By passing distilled process water through the first space 14 and the second space 16 of the membrane module 10, the osmotic pressure difference between the first space 14 side and the second space 16 side of the semipermeable membrane 12 can be reduced, and high concentration of ions in the distilled process water can be concentrated with less energy consumption. That is, the distilled water having a high concentration and containing ions can be concentrated at low cost, and the amount of waste liquid having a high ion concentration can be reduced.

As a method for adjusting the supply flow rate, permeate flow rate, and concentrate flow rate of the distilled water to be supplied to the membrane module 10, for example, the following method may be used.

An inverter 20 for controlling the driving frequency is provided to the pump 18, and the supply flow rate of the distilled water to the membrane module 10 is adjusted. The inverter 20 is preferably provided in the pump 18, but may be omitted. The distilled water may be supplied to both the first space 14 side and the second space 16 side, the valve 22 may be provided before the inlet of the second space 16, the valve 23 may be provided at the outlet of the first space 14, and the ratio of the flow rate of the supplied water to the first space 14 side to the flow rate of the supplied water to the second space 16 side may be adjusted by manually or automatically adjusting the opening degrees of the valve 22 and the valve 23.

When the permeate flow rate and the concentrate flow rate are insufficient, the frequency of the inverter 20 of the pump 18 may be increased to increase the supply amount of the distilled water.

A valve 23 capable of adjusting the opening/closing degree is provided at the outlet of the first space 14 in the pipe 28, and the opening degree of the valve 23 enables the concentrated water flow rate, the pressure adjustment at the inlet of the first space 14, and the pressure adjustment at the outlet of the first space 14.

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

The distilled water may be supplied to the first space 14 side and the second space 16 side by different pumps. In the case where the distilled water is supplied by different pumps, an inverter for controlling the driving frequency may be provided for each pump.

By supplying distilled water of 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 necessary pressure can be reduced. As a result, the distilled water of a concentration which cannot be concentrated by the conventional reverse osmosis membrane method can be concentrated.

In this way, ammonia can be recovered from the water containing ammonia, and valuable substances and water can be further recovered from the distilled water after the recovered substances are removed. The ammonia is recovered from the ammonia-containing water by distillation, and the distilled water is concentrated to a high concentration by a semipermeable membrane module, whereby the recovery can be increased, the amount of discharged water can be reduced, and the water recovery can be improved.

Another example of the water treatment apparatus according to the embodiment of the present invention is schematically shown in fig. 2, and the configuration thereof will be described.

The water treatment apparatus 2 shown in fig. 2 includes a distillation apparatus 11 as a first recovery means for recovering at least one of ammonia and ammonium ions from water containing ammonia as a first recovered product, and a membrane module 10 as a second recovery means for introducing distilled water from the distillation apparatus 11 into the first space 14, pressurizing the first space 14, allowing water contained in the distilled water to permeate the semipermeable membrane 12, thereby obtaining a second recovered product as concentrated water, and introducing at least a part of the concentrated water into the second space 16 to obtain diluted water, using a semipermeable membrane module having a first space (concentrating side) 14 and a second space (permeate side) 16 partitioned by the semipermeable membrane 12. The water treatment apparatus 2 may be provided with a distillation treatment water tank for storing distilled treatment water between the distillation apparatus 11 and the membrane module 10.

In the water treatment apparatus 2 of fig. 2, a pipe 25 is connected to an inlet of the distillation apparatus 11. A pipe 27 is connected to the first recycle outlet of the distillation apparatus 11. The distilled water outlet of the distillation apparatus 11 is connected to the first space inlet of the membrane module 10 via a pipe 24 by 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 branching 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 a valve 32. A pipe 36 is connected to the second space outlet of the membrane module 10.

The pump 18 is, for example, a pressurizing pump that sucks in distilled water and pressurizes and discharges the distilled water to the membrane module 10, and is driven at a rotational speed corresponding to the input driving frequency. The pump 18 is provided with an inverter 20 that outputs a driving frequency corresponding to an input command signal to the pump 18, for example. The valves 23 and 32 are, for example, valves whose opening/closing degree can be manually or automatically adjusted.

The membrane module 10 is a device which has a first space 14 and a second space 16 partitioned by a semipermeable membrane 12, which is configured to allow distilled water to pass through the first space inlet of the membrane module 10 to the first space 14, and to allow at least a part of concentrated water discharged from the first space outlet of the first space 14 of the membrane module 10 to pass through the second space inlet of the membrane module 10 to the second space 16, thereby pressurizing the first space 14, and which is configured to allow water contained in the distilled water in the first space 14 to permeate through the semipermeable membrane 12 to the second space 16 to concentrate the water. That is, in the water treatment apparatus 2, the semipermeable membrane 12 is used to concentrate the distilled water. The membrane module 10 is a device that supplies distilled water 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 to perform concentration treatment.

In the water treatment apparatus 2, ammonia-containing water containing ammonia is supplied to the distillation apparatus 11 through a pipe 25. Distillation is performed in the distillation apparatus 11, and at least one of ammonia and ammonium ions is recovered as a first recovered product from water containing ammonia (first recovery step). The first recovered material is discharged through the pipe 27.

The distilled water obtained in the distillation apparatus 11 is pressurized and fed from the first space inlet of the membrane module 10 to the first space 14 by the pump 18 through the pipe 24 with the valve 23 opened. A part of the water contained in the pressurized distilled water is transmitted from the first space 14 to the second space 16 through the semipermeable membrane 12. At this time, most of the ions and the like cannot pass through the semipermeable membrane 12, and therefore, the water in the first space 14 which does not pass through the semipermeable membrane 12 is concentrated. On the other hand, in the second space 16, a part of the concentrated water supplied through the pipe 34 and the permeate hydration flow having a low ion concentration that permeates the semipermeable membrane 12 exert a dilution effect. The concentrated water obtained in the first space 14 is discharged as the second recovered material from the first space outlet through the pipe 28, and at least a part of the concentrated water is fed from the second space inlet of the membrane module 10 to the second space 16 through the pipe 34 branched from the pipe 28 in the state where the valve 32 is opened, thereby introducing water. The dilution 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 water contained in the distilled water in the first space 14 is permeated into the second space 16 through the semipermeable membrane 12, so that concentrated water (second recovered product) is obtained in the first space 14 (concentration step), and diluted water is obtained in the second space 16 (dilution step) (the above-described second recovery step).

Here, the pipes 24, 28, 34, the pump 18, and the like function as a supply means for supplying distilled water to the first space 14 of the membrane module 10 and supplying 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.

The dilution water obtained in the second space 16 may be discharged to the outside of the system through the pipe 36, or may be supplied to a dilution water tank and stored as needed, and then discharged to the outside of the system, or may be reused. At least a part of the dilution water may be fed to the distilled water tank, and mixed with the distilled water in the distilled water tank. At least a part of the dilution water may be further treated with another treatment, for example, reverse osmosis membrane treatment as described below.

By passing distilled water into the first space 14 of the membrane module 10 and passing at least a part of the concentrated water obtained in the first space 14 into the second space 16, the osmotic pressure difference between the first space 14 side and the second space 16 side of the semipermeable membrane 12 can be reduced, and the high concentration of ions in the distilled water can be concentrated with less energy consumption. That is, the distilled water having a high concentration and containing ions can be concentrated at low cost, and the amount of waste liquid having a high ion concentration can be reduced.

An inverter 20 for controlling the driving frequency is provided to the pump 18, and the supply flow rate of the distilled water to the membrane module 10 is adjusted. The inverter 20 is preferably provided in the pump 18, but may be omitted. The distilled water may be supplied to the first space 14 side, the valve 23 may be provided at the outlet of the first space 14, the valve 32 may be provided before the inlet of the second space 16, and the ratio of the flow rate of the supplied water to the first space 14 side to the flow rate of the supplied water to the second space 16 side may be adjusted by manually or automatically adjusting the opening degree of the valves 23 and 32.

A valve 23 capable of adjusting the opening and closing degree can be provided at the outlet of the first space 14 of the pipe 28, and the flow rate of concentrate and the pressure of the inlet of the first space 14 and the outlet of the first space 14 can be adjusted by the opening degree of the valve 23.

Further, a concentrated water tank for storing concentrated water may be provided in the middle of the pipe 34, and distilled water may be supplied to the first space 14 side and the second space 16 side of the concentrated water by different pumps. In the case where the distilled water and the concentrated water are supplied by different pumps, an inverter for controlling the driving frequency may be provided for each pump.

By introducing distilled water into the first space 14 and introducing concentrated water of a similar concentration into the second space 16, the osmotic pressure generated by the semipermeable membrane 12 can be reduced, and the necessary pressure can be reduced. As a result, the distilled water of a concentration which cannot be concentrated by the conventional reverse osmosis membrane method can be concentrated.

In the water treatment method and the water treatment apparatus according to the present embodiment, the sulfate ion concentration of the ammonia-containing water before the liquid is fed to the distillation apparatus 11 (in the case of the pretreatment unit, after the pretreatment and before the liquid is fed to the distillation apparatus 11) is 6000mg/L or more, for example, and the ammonium ion concentration is 2000mg/L or more. The sulfate ion concentration of the ammonia-containing water is preferably 20000mg/L or more, more preferably in the range of 20000 to 250000 mg/L. The concentration of ammonium ions in the ammonia-containing water is preferably 2000mg/L or more, more preferably in the range of 2000 to 100000 mg/L.

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

The flow rate of the first space 14 side is preferably made larger than the flow rate of the second space 16 side. If the flow rate of the first space 14 side is equal to or less than the flow rate of the second space 16 side, the permeate 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 flow rate adjustment means for making the flow rate of the first space larger than the flow rate of the second space.

If the permeation flux is too large, there are problems such as a large concentration difference, a high risk of fouling, and an excessively high pressure. In addition, if the permeation flux is too small, the concentration efficiency may be deteriorated. From these viewpoints, the permeation flux of the membrane module 10 is preferably in the range of 0.005m/d to 0.05m/d, more preferably in the range of 0.015m/d to 0.04 m/d. The permeate flux is defined as the permeate flux per unit time per 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 permeate flux adjusting means for controlling permeate flux in the above-described range.

The positions and the number of the valves may be larger than those shown in fig. 1 and 2, or may be provided in at least one of the other pipes. In addition, a flowmeter serving as a flow rate measuring means for measuring a flow rate and a manometer serving as a pressure measuring means for measuring a pressure may be provided in at least one of the pipes.

In the water treatment method and the water treatment apparatus according to the present embodiment, a multi-stage semipermeable membrane module may be used. Fig. 3, 4 and 5 show examples of the water treatment apparatus having such a structure. The water treatment apparatus shown in fig. 3, 4 and 5 has a structure in which semipermeable membrane modules are combined in series of 3 stages.

The water treatment apparatus 3 shown in fig. 3 includes a distillation apparatus 11 as a first recovery means for recovering at least one of ammonia and ammonium ions from water containing ammonia as a first recovered product, and a second recovery means for pressurizing the distilled water of the distillation apparatus 11 to the first space 14 of the semipermeable membrane module of the 1 st stage, thereby allowing water contained in the distilled water to permeate the semipermeable membrane 12, thereby obtaining concentrated water, further using the semipermeable membrane module of the subsequent stage for the concentrated water, thereby obtaining a second recovered product as concentrated water, and allowing the second space 16 of the semipermeable membrane module of each stage to pass through a part of the distilled water or a part of the water, thereby obtaining concentrated water, wherein the semipermeable membrane module of the first recovery means is a semipermeable membrane module having a first space (concentrating side) 14 and a second space (permeate side) 16 separated by the semipermeable membrane 12, and the distilled water of the distillation apparatus 11 is passed through the first space 14 of the semipermeable membrane module of the 1 st stage. Each membrane module has a first space 14 and a second space 16 separated by a semi-permeable membrane 12. The water treatment apparatus 3 may include a dilution water tank 60a for storing the dilution water from the 1 st stage membrane module 10a, a dilution water tank 60b for storing the dilution water from the 2 nd stage membrane module 10b, and a dilution water tank 60c for storing the dilution water from the 3 rd stage membrane module 10 c. The membrane module 10 is a device for supplying distilled water to the first space and the second space of the 1 st stage membrane module, and sequentially supplying the concentrated water to the first space and the second space of the subsequent stage membrane module to perform concentration treatment. The water treatment apparatus 3 may be provided with a distilled water tank for storing distilled water between the distillation apparatus 11 and the membrane module 10.

In the water treatment apparatus 3 of fig. 3, a pipe 25 is connected to an inlet of the distillation apparatus 11. A pipe 27 is connected to the first recycle outlet of the distillation apparatus 11. The distilled water outlet of the distillation apparatus 11 is connected to the first space inlet of the 1 st stage membrane module 10a via a pipe 40 by 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 the valve 22 a. The second space outlet of the 1 st stage membrane module 10a is connected to the inlet of the dilution water tank 60a through the pipe 46. The first space outlet of the 1 st stage membrane module 10a and the first space inlet of the 2 nd stage membrane module 10b are connected by piping 44. The piping 48 branched from the piping 44 is connected to the second space inlet of the 2 nd stage membrane module 10b via the valve 22 b. The second space outlet of the 2 nd stage membrane module 10b is connected to the inlet of the dilution water tank 60b through the pipe 52. The first space outlet of the 2 nd stage membrane module 10b is connected to the first space inlet of the 3 rd stage membrane module 10c by a piping 50. The piping 54 branched from the piping 50 is connected to the second space inlet of the 3 rd membrane module 10c via the valve 22 c. The second space outlet of the 3 rd stage membrane module 10c is connected to the inlet of the dilution water tank 60c through a pipe 58. A pipe 56 is connected to the first space outlet of the 3 rd stage membrane module 10c via a valve 23.

The membrane module 10 is a device in which distilled water is supplied to the first space and the second space of the membrane module of the 1 st stage by using a multistage membrane module having the first space 14 and the second space 16 partitioned by the semipermeable membrane 12, the concentrated water is sequentially supplied to the first space and the second space of the membrane module of the subsequent stage, and the first space 14 of each stage is pressurized, whereby the water contained in the first space 14 is concentrated by passing through the semipermeable membrane 12 to the second space 16. That is, in the membrane module 10, the semipermeable membrane 12 is used to concentrate the distilled water, and the concentrate is further concentrated by using the semipermeable membrane 12 of the next stage.

In the water treatment apparatus 3, ammonia-containing water containing ammonia is supplied to the distillation apparatus 11 through a pipe 25. Distillation is performed in the distillation apparatus 11, and at least one of ammonia and ammonium ions is recovered from the ammonia-containing water as a first recovered product (first recovery step). The first recovered material is discharged through the pipe 27.

The distilled water obtained in the distillation apparatus 11 is fed to the first space 14a of the 1 st stage membrane module 10a through the pipe 40 by the pump 18 in a state where the valve 23 is opened, and the distilled water branched from the pipe 40 is fed to the second space 16a of the 1 st stage membrane module 10a through the pipe 42 in a state where the valve 22a is opened. In the segment 1 membrane module 10a, the first space 14a is pressurized, and water contained in the first space 14a is transmitted to the second space 16a through the semipermeable membrane 12a (concentration step (segment 1)), and dilution water is obtained in the second space 16a (dilution step (segment 1)). The dilution water obtained in the second space 16a of the stage 1 membrane module 10a is stored in the dilution water tank 60a through the pipe 46 as needed, and then discharged to the outside of the system.

The concentrated water obtained in the first space 14a of the 1 st stage membrane module 10a is fed to the first space 14b of the 2 nd stage membrane module 10b through the pipe 44, and the concentrated water branched from the pipe 44 is fed to the second space 16b of the 2 nd stage membrane module 10b through the pipe 48 in a state where the valve 22b is opened. In the 2 nd stage membrane module 10b, the first space 14b is pressurized, and water contained in the first space 14b is transmitted to the second space 16b through the semipermeable membrane 12b (concentration step (2 nd stage)), and dilution water is obtained in the second space 16b (dilution step (2 nd stage)). The dilution water obtained in the second space 16b of the 2 nd stage membrane module 10b is stored in the dilution water tank 60b through the pipe 52 as needed, and then discharged to the outside of the system.

The concentrated water obtained in the first space 14b of the 2 nd stage membrane module 10b is fed to the first space 14c of the 3 rd stage membrane module 10c through the pipe 50, and the concentrated water branched from the pipe 50 is fed to the second space 16c of the 3 rd stage membrane module 10c through the pipe 54 in a state where the valve 22c is opened. In the 3 rd-stage membrane module 10c, the first space 14c is pressurized, and water contained in the first space 14c is transmitted to the second space 16c through the semipermeable membrane 12c (concentration step (3 rd stage)), and dilution water is obtained in the second space 16c (dilution step (3 rd stage)) (the above is the second recovery step). The dilution water obtained in the second space 16c of the 3 rd stage membrane module 10c is stored in a dilution water tank 60c through a pipe 58 as needed, and then discharged to the outside of the system. The concentrated water obtained in the first space 14c of the 3 rd stage membrane module 10c is discharged as a second recovered product through the pipe 56.

Here, the pump 18, the pipes 40, 42, 44, 48, 50, 54, and the like function as supply means for supplying distilled water or concentrated water to the first spaces 14a, 14b, 14c and the second spaces 16a, 16b, 16c of the membrane modules 10a, 10b, 10c of the respective stages.

The dilution 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 fed to the dilution water tanks 60a, 60b, 60c as needed, stored, and then discharged to the outside of the system, or may be reused. At least a part of the dilution water may be fed to the distillation treatment water tank, and mixed with the distillation treatment water in the distillation treatment water tank. At least a part of the dilution water may be further treated with another treatment, for example, reverse osmosis membrane treatment as described below.

As described above, at least one of ammonia and ammonium ions is recovered from the ammonia-containing water to be treated as a first recovered product, and further, the concentrated water in which the ions are concentrated (concentrated water in the final stage) is recovered as a second recovered product, thereby obtaining dilution water (dilution water in each stage), and reducing the volume of the ammonia-containing water. In addition, the first recycle, the second recycle, and the dilution water can be reused.

The water treatment apparatus 4 shown in fig. 4 includes a distillation apparatus 11 as a first recovery means for recovering at least one of ammonia and ammonium ions from water containing ammonia as a first recovered product, and a second recovery means for pressurizing the distilled water of the distillation apparatus 11 in the first space 14 of the semipermeable membrane module of the 1 st stage, and allowing water contained in the distilled water to permeate the semipermeable membrane 12 to obtain concentrated water by using the semipermeable membrane module of the subsequent stage for the concentrated water to obtain a second recovered product as concentrated water, and allowing at least a part of the concentrated water to pass through the second space 16 of the semipermeable membrane module of each stage to obtain diluted water, wherein the first recovery means includes a semipermeable membrane module 11 having a first space (concentrate side) 14 and a second space (permeate side) 16 separated by the semipermeable membrane 12, and the first space 14 is filled with distilled water. Each membrane module has a first space 14 and a second space 16 separated by a semi-permeable membrane 12. The water treatment apparatus 4 may include a dilution water tank 62a for storing the dilution water from the 1 st stage membrane module 10a, a dilution water tank 62b for storing the dilution water from the 2 nd stage membrane module 10b, and a dilution water tank 62c for storing the dilution water from the 3 rd stage membrane module 10 c. The membrane module 10 is a device for supplying distilled water to the first space of the 1 st stage membrane module, and sequentially supplying the distilled water to the first space of the subsequent stage membrane module and the second space thereof to perform concentration treatment. The water treatment apparatus 4 may be provided with a distilled water tank for storing distilled water between the distillation apparatus 11 and the membrane module 10.

In the water treatment apparatus 4 of fig. 4, a pipe 25 is connected to an inlet of the distillation apparatus 11. A pipe 27 is connected to the first recycle outlet of the distillation apparatus 11. The distilled water outlet of the distillation apparatus 11 is connected to the first space inlet of the 1 st stage membrane module 10a via a pipe 40 by a pump 18. The first space outlet of the 1 st stage membrane module 10a and the first space inlet of the 2 nd stage membrane module 10b are connected by piping 44. The piping 64 branched from the piping 44 is connected to the second space inlet of the membrane module 10a via the valve 32 a. The second space outlet of the 1 st stage membrane module 10a is connected to the inlet of the dilution water tank 62a through a pipe 66. The first space outlet of the 2 nd stage membrane module 10b is connected to the first space inlet of the 3 rd stage membrane module 10c by a piping 50. A pipe 68 branched from the pipe 50 is connected to the second space inlet of the membrane module 10b via the valve 32 b. The second space outlet of the 2 nd stage membrane module 10b is connected to the inlet of the dilution water tank 62b through a pipe 70. A pipe 56 is connected to the first space outlet of the 3 rd stage membrane module 10c via a valve 23. A pipe 72 branching 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 a valve 32 c. The second space outlet of the 3 rd stage membrane module 10c is connected to the inlet of the dilution water tank 62c through a pipe 74.

The membrane module 10 is the following: the distilled water is supplied to the first space of the 1 st stage membrane module by using a multistage membrane module having a first space 14 and a second space 16 partitioned by a semipermeable membrane 12, and the concentrated water is sequentially supplied to the first space of the subsequent stage membrane module and the second space thereof, and the first space 14 of each stage is pressurized, whereby the water contained in the first space 14 is concentrated by passing through the semipermeable membrane 12 to the second space 16. That is, in the membrane module 10, the distilled water is concentrated using the semipermeable membrane 12, and the concentrated water is further concentrated using the semipermeable membrane 12 of the next stage.

In the water treatment apparatus 4, ammonia-containing water containing ammonia is supplied to the distillation apparatus 11 through a pipe 25. Distillation is performed in the distillation apparatus 11, and at least one of ammonia and ammonium ions is recovered as a first recovered product from water containing ammonia (first recovery step). The first recovered material is discharged through the pipe 27.

The distilled water obtained by the distillation apparatus 11 is fed to the first space 14a of the 1 st stage membrane module 10a through the pipe 40 by the pump 18 in a state where the valve 23 is opened. In the segment 1 membrane module 10a, the first space 14a is pressurized, and water contained in the first space 14a is transmitted to the second space 16a through the semipermeable membrane 12a (concentration step (segment 1)), and dilution water is obtained in the second space 16a (dilution step (segment 1)). The concentrated water obtained in the first space 14a of the 1 st stage membrane module 10a is fed to the first space 14b of the 2 nd stage membrane module 10b through the pipe 44, and the concentrated water branched from the pipe 44 is fed to the second space 16a of the 1 st stage membrane module 10a through the pipe 64 in a state where the valve 32a is opened. The dilution water obtained in the second space 16a of the stage 1 membrane module 10a is stored in the dilution water tank 62a through the pipe 66 as needed, and then discharged to the outside of the system.

In the 2 nd stage membrane module 10b, the first space 14b is pressurized, and water contained in the first space 14b is transmitted to the second space 16b through the semipermeable membrane 12b (concentration step (2 nd stage)), and dilution water is obtained in the second space 16b (dilution step (2 nd stage)). The concentrated water obtained in the first space 14b of the 2 nd stage membrane module 10b is fed to the first space 14c of the 3 rd stage membrane module 10c through the pipe 50, and the concentrated water branched from the pipe 50 is fed to the second space 16b of the 2 nd stage membrane module 10b through the pipe 68 in a state where the valve 32b is opened. The dilution water obtained in the second space 16b of the 2 nd stage membrane module 10b is stored in the dilution water tank 62b through the pipe 70 as needed, and then discharged to the outside of the system.

In the 3 rd-stage membrane module 10c, the first space 14c is pressurized, and water contained in the first space 14c is transmitted to the second space 16c through the semipermeable membrane 12c (concentration step (3 rd stage)), and dilution water is obtained in the second space 16c (dilution step (3 rd stage)) (the above, the second recovery step). The concentrated water obtained in the first space 14c of the 3 rd stage membrane module 10c is discharged as a second recovered product through the pipe 56. The concentrated water branched from the pipe 56 is sent to the second space 16c of the 3 rd membrane module 10c through the pipe 72 in a state where the valve 32c is opened. The dilution water obtained in the second space 16c of the 3 rd stage membrane module 10c is stored in the dilution water tank 62c through the pipe 74 as needed, 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 function as a supply means for supplying distilled water or concentrated water to the first spaces 14a, 14b, 14c and the second spaces 16a, 16b, 16c of the membrane modules 10a, 10b, 10c of the respective stages.

The dilution 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 fed to the dilution water tanks 62a, 62b, 62c as needed, stored, and then discharged to the outside of the system, or may be reused. At least a part of the dilution water may be fed to the distillation treatment water tank, and mixed with the distillation treatment water in the distillation treatment water tank. At least a part of the dilution water may be further treated with another treatment, for example, reverse osmosis membrane treatment as described below.

In the case of using a multistage membrane module, water passage on the second space side may be performed in series. An example of a water treatment apparatus having such a structure is shown in fig. 5.

The water treatment apparatus 5 shown in fig. 5 includes a distillation apparatus 11 as a first recovery means for recovering at least one of ammonia and ammonium ions from water containing ammonia as a first recovered product, and a second recovery means for pressurizing the distilled water of the distillation apparatus 11 to the first space 14 of the semipermeable membrane module of the 1 st stage, thereby allowing water contained in the distilled water to permeate the semipermeable membrane 12, thereby obtaining concentrated water, further using the semipermeable membrane module of the subsequent stage for the concentrated water, and allowing at least a part of the concentrated water or at least a part of the diluted water obtained from the other semipermeable membrane module to pass through the second space 16 of the semipermeable membrane module of each stage, thereby obtaining diluted water, wherein the first recovery means includes a semipermeable membrane module 11 having a first space (concentrating side) 14 and a second space (permeate side) 16 partitioned by the semipermeable membrane 12, and the first space 14 is connected in multiple stages. Each membrane module has a first space 14 and a second space 16 separated by a semi-permeable membrane 12. The membrane module 10 is a device for supplying distilled water to the first space of the 1 st stage membrane module, and sequentially supplying concentrated water to the first space of the subsequent stage membrane module to perform concentration treatment. The water treatment apparatus 5 may be provided with a distillation treatment water tank for storing distilled treatment water between the distillation apparatus 11 and the membrane module 10.

In the water treatment apparatus 5 of fig. 5, a pipe 25 is connected to an inlet of the distillation apparatus 11. A pipe 27 is connected to the first recycle outlet of the distillation apparatus 11. The distilled water outlet of the distillation apparatus 11 is connected to the first space inlet of the 1 st stage membrane module 10a via a pipe 40 by a pump 18. The first space outlet of the 1 st stage membrane module 10a and the first space inlet of the 2 nd stage membrane module 10b are connected by piping 44. The first space outlet of the 2 nd stage membrane module 10b is connected to the first space inlet of the 3 rd stage membrane module 10c by a piping 50. A pipe 56 is connected to the first space outlet of the 3 rd stage membrane module 10c via a valve 23. A pipe 76 branching 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 3 rd stage membrane module 10c is connected to the second space inlet of the second stage membrane module 10b by piping 78. The second space outlet of the 2 nd stage membrane module 10b is connected to the second space inlet of the 1 st stage membrane module 10a by piping 80. A pipe 82 is connected to the second space outlet of the stage 1 membrane module 10 a.

The membrane module 10 is the following: the method comprises the steps of using a multistage membrane module having a first space 14 and a second space 16 partitioned by a semipermeable membrane 12, supplying distilled water to the first space of the 1 st stage membrane module, sequentially passing the concentrated water to the first space of the later stage membrane module in series, supplying at least a part of the concentrated water of the final stage membrane module to the second space of the membrane module, passing the obtained diluted water to the second space of the former stage membrane module in series, pressurizing the first space 14 of each stage, and allowing the water contained in the first space 14 to permeate to the second space 16 via the semipermeable membrane 12 to concentrate the water. That is, in the membrane module 10, the distilled water is concentrated using the semipermeable membrane 12, and the concentrated water is further concentrated using the semipermeable membrane 12 of the next stage.

In the water treatment apparatus 5, ammonia-containing water containing ammonia is supplied to the distillation apparatus 11 through a pipe 25. Distillation is performed in the distillation apparatus 11, and at least one of ammonia and ammonium ions is recovered as a first recovered product from water containing ammonia (first recovery step). The first recovered material is discharged through the pipe 27.

The distilled water obtained in the distillation apparatus 11 is fed to the first space 14a of the 1 st stage membrane module 10a through the pipe 40 by the pump 18 in a state where the valve 23 is opened. On the other hand, the dilution water fed through the second space 16c of the 3 rd stage membrane module 10c and the second space 16b of the 2 nd stage membrane module 10b described later is fed to the second space 16a of the 1 st stage membrane module 10a through the pipe 80. In the segment 1 membrane module 10a, the first space 14a is pressurized, and water contained in the first space 14a is transmitted to the second space 16a through the semipermeable membrane 12a (concentration step (segment 1)), and dilution water is obtained in the second space 16a (dilution step (segment 1)). The concentrated water obtained in the first space 14a of the 1 st stage membrane module 10a is fed to the first space 14b of the 2 nd stage membrane module 10b through the pipe 44. The dilution water obtained in the second space 16a of the stage 1 membrane module 10a is discharged to the outside of the system through the pipe 82.

In the 2 nd stage membrane module 10b, the dilution water fed through the second space 16c of the 3 rd stage membrane module 10c described later is fed to the second space 16b of the 2 nd stage membrane module 10b through the piping 78. The first space 14b is pressurized, and water contained in the first space 14b is transmitted to the second space 16b through the semipermeable membrane 12b (concentration step (2 nd stage)), and dilution water is obtained in the second space 16b (dilution step (2 nd stage)). The concentrated water obtained in the first space 14b of the 2 nd stage membrane module 10b is sent to the first space 14c of the 3 rd stage membrane module 10c through the pipe 50. The dilution water obtained in the second space 16b of the 2 nd stage membrane module 10b is sent to the second space 16a of the 1 st stage membrane module 10a through the pipe 80.

In the 3 rd membrane module 10c, the concentrated water obtained in the first space 14c of the 3 rd membrane module 10c is fed 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 transmitted to the second space 16c through the semipermeable membrane 12c (concentration step (3 rd stage)), and the dilution water is obtained in the second space 16c (dilution step (3 rd stage)) (the above is the second recovery step). The concentrated water obtained in the first space 14c of the 3 rd stage membrane module 10c is discharged as a second recovered product through the pipe 56. The concentrated water branched from the pipe 56 is fed to the second space 16c of the 3 rd membrane module 10c through the pipe 76 in a state where the valve 32 is opened. The dilution water obtained in the second space 16c of the 3 rd stage membrane module 10c is sent to the second space 16b of the 2 nd stage membrane module 10b through the pipe 78.

Here, the pump 18, the pipes 40, 44, 50, 56, 76, 78, 80, and the like function as a supply means for supplying distilled treatment water, concentrated water, or dilution water to the first spaces 14a, 14b, 14c and the second spaces 16a, 16b, 16c of the membrane modules 10a, 10b, 10c of the respective stages.

The dilution water obtained in the second space 16a of the membrane module 10a may be discharged to the outside of the system, or may be fed to a dilution water tank to be stored as needed, and then discharged to the outside of the system, or may be reused. At least a part of the dilution water may be fed to the distillation treatment water tank, and mixed with the distillation treatment water in the distillation treatment water tank. At least a part of the dilution water may be further treated with another treatment, for example, reverse osmosis membrane treatment as described below.

As described above, at least one of ammonia and ammonium ions is recovered from the ammonia-containing water to be treated as a first recovered product, and further, the ion-concentrated water (final stage concentrated water) is recovered as a second recovered product to obtain dilution water (stage 1 dilution water), thereby reducing the volume of the ammonia-containing water. In addition, the first recycle, the second recycle, and the dilution water can be reused.

In the water treatment apparatus 3 shown in fig. 3, the water treatment apparatus 4 shown in fig. 4, and the water treatment apparatus 5 shown in fig. 5, the concentrated water supplied to each membrane module is concentrated as the membrane module goes from the 1 st stage to the subsequent stage, and thus becomes a high concentration. Since the concentration is high, the concentration can be made to a concentration which is difficult to be concentrated by the influence of osmotic pressure in the conventional reverse osmosis membrane method by the present method which can reduce osmotic pressure.

In the case of supplying distilled water to the 1 st stage membrane module 10a, for example, a pressure of 7MPa or less is applied, and the concentrated water to the subsequent stage membrane module may be supplied by the pressure applied to the 1 st stage membrane module 10 a. The inlet pressure of the first space 14 in each membrane module is preferably in the range of 7MPa or less, the inlet pressure of the second space 16 is preferably a pressure smaller than the inlet pressure of the first space 14, and the inlet pressure of the second space 16 is more preferably 50% or less of the inlet pressure of the first space 14. This reduces the risk of breakage of the semipermeable membrane due to pressure.

The flow rate of each membrane module 10 on the first space 14 side is preferably set to be larger than the flow rate of each membrane module on the second space 16 side. If the flow rate of the first space 14 side is equal to or less than the flow rate of the second space 16 side, the flow rate of the first space 14 side of the membrane module in the subsequent stage may be insufficient. 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 flow rate adjusting means for making the flow rate of the first space larger than the flow rate of the second space.

If the permeation flux is too large, the concentration polarization of the membrane surface becomes large, and there is a problem that the risk of fouling becomes high and the pressure becomes too high. In addition, if the permeation flux is too small, the concentration efficiency may be deteriorated. From these viewpoints, the permeation flux of each membrane module 10 is preferably in the range of 0.005m/d to 0.05m/d, more preferably in the range of 0.015m/d to 0.04 m/d. 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 permeate flux regulating means for controlling permeate flux in the above-described range.

The positions and the number of the valves may be larger than those shown in fig. 3, 4, and 5, or may be provided in at least one of the other pipes. Further, at least one of the pipes may be provided with a flowmeter serving as a flow rate measuring means for measuring a flow rate and a pressure gauge serving as a pressure measuring means for measuring a pressure.

Fig. 3, 4, and 5 show an example of the device configuration, and the arrangement of the semipermeable membrane modules, the method of supplying the supplied water, and the like may be appropriately changed.

The water treatment apparatus of fig. 5 is preferable because the water is supplied in series to the first space and the second space of each of the membrane modules, and therefore, compared with the water treatment apparatus of fig. 3 and 4, the entire water amount can be suppressed, and the power of the pump can be reduced.

In the water treatment method and the water treatment apparatus 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. Fig. 6 and 7 show examples of the water treatment apparatus having such a configuration. The water treatment apparatus shown in fig. 6 and 7 has the following structure: in the 1 st stage, the semipermeable membrane modules are combined in a 4-column parallel manner, in the 2 nd stage, the semipermeable membrane modules are combined in a 4-column parallel manner, in the 3 rd stage, the semipermeable membrane modules are combined in a 2-column parallel manner, in the 4 th stage, the semipermeable membrane modules are combined in a 2-column parallel manner, and are connected in series as 4 stages.

The water treatment apparatus 6 shown in fig. 6 includes a distillation apparatus 11 as a first recovery unit for recovering at least one of ammonia and ammonium ions from water containing ammonia as a first recovered product, and a second recovery unit for pressurizing the first space 14 of the semipermeable membrane module of the 1 st stage by using a semipermeable membrane module having a first space (concentrating side) 14 and a second space (permeate side) 16 separated by the semipermeable membrane 12, and passing distilled water from the distillation apparatus 11 through the first space 14 of the semipermeable membrane module of the 1 st stage, so that water contained in the distilled water permeates the semipermeable membrane 12, thereby obtaining concentrated water, and further using the semipermeable membrane module of the subsequent stage for the concentrated water, thereby obtaining a part of the concentrated water, and further passing a part of the water of the semipermeable membrane module or a part of the concentrated water through the second space 16 of each stage, thereby obtaining diluted water. The 1 st-stage membrane module unit 100a includes, for example, 4 membrane modules connected in parallel, the 2 nd-stage membrane module unit 100b includes, for example, 4 membrane modules connected in parallel, the 3 rd-stage membrane module unit 100c includes, for example, 2 membrane modules connected in parallel, and the 4 th-stage membrane module unit 100d includes, for example, 2 membrane modules connected in parallel. Each membrane module 10 has a first space 14 and a second space 16 separated by a semi-permeable membrane 12. The water treatment apparatus 6 may be provided with a distilled water tank 84 for storing distilled water and a concentrated water tank 86 for storing concentrated water from the 4 th-stage membrane module unit 100 d. The membrane module unit 100 is a device that supplies distilled water to the first space and the second space of each membrane module of the membrane module unit of the 1 st stage, and sequentially supplies the distilled water to the first space and the second space of each membrane module of the membrane module unit of the subsequent stage, thereby performing concentration treatment.

In the water treatment apparatus 6 of fig. 6, a pipe 25 is connected to an inlet of the distillation apparatus 11. A pipe 27 is connected to the first recycle outlet of the distillation apparatus 11. The distilled water outlet of the distillation apparatus 11 is connected to the inlet of the distilled water tank 84 via a pipe 29. The outlet of the distillation treatment water tank 84 is connected to the first space inlet and the second space inlet of each membrane module of the 1 st stage membrane module unit 100a via the pump 18 by the pipe 88. The first space outlet of each membrane module of the 1 st-stage membrane module unit 100a is connected to the first space inlet and the second space inlet of each membrane module of the 2 nd-stage membrane module unit 100b by piping 90. The first space outlet of each membrane module of the 2 nd stage membrane module unit 100b is connected to the first space inlet and the second space inlet of each membrane module of the 3 rd stage membrane module unit 100c by piping 94. The first space outlet of each membrane module of the 3 rd-stage membrane module unit 100c is connected to the first space inlet and the second space inlet of each membrane module of the 4 th-stage membrane module unit 100d by piping 98. The first space outlet of each membrane module of the 4 th-stage membrane module unit 100d is connected to the inlet of the concentrate water tank 86 by a pipe 104. Piping 92 is connected to the second space outlet of each membrane module of the 1 st stage membrane module unit 100a, piping 96 is connected to the second space outlet of each membrane module of the 2 nd stage membrane module unit 100b, piping 102 is connected to the second space outlet of each membrane module of the 3 rd stage membrane module unit 100c, piping 106 is connected to the second space outlet of each membrane module of the 4 th stage membrane module unit 100d, and the piping 96, 102, 106 may be joined to the piping 92.

The membrane module unit 100 is the following: using a multistage membrane module unit including a membrane module 10 having a first space 14 and a second space 16 partitioned by a semipermeable membrane 12, distilled water is supplied to the first space and the second space of each membrane module of the 1 st stage membrane module unit, and the concentrated water is sequentially supplied to the first space and the second space of each membrane module of the subsequent stage membrane module unit, and the first space 14 of each stage membrane module is pressurized, whereby the water contained in the first space 14 is concentrated by passing through the semipermeable membrane 12 to the second space 16. That is, in the membrane module unit 100, the distilled water is concentrated using the semipermeable membrane 12, and the concentrated water is further concentrated using the semipermeable membrane 12 of the next stage.

In the water treatment apparatus 6, ammonia-containing water containing ammonia is supplied to the distillation apparatus 11 through a pipe 25. Distillation is performed in the distillation apparatus 11, and at least one of ammonia and ammonium ions is recovered as a first recovered product from water containing ammonia (first recovery step). The first recovered material is discharged through the pipe 27.

After the distilled water obtained by the distillation apparatus 11 is stored in the distilled water tank 84 as needed, the distilled water is pumped from the distilled water tank 84 to the first space 14 and the second space 16 of each membrane module of the 1 st stage membrane module unit 100a by the pump 18 through the pipe 88. In each membrane module of the stage 1 membrane module unit 100a, the first space 14a is pressurized, and water contained in the first space 14 is transmitted to the second space 16 through the semipermeable membrane 12 (concentration step (stage 1)), and dilution water is obtained in the second space 16 (dilution step (stage 1)). The dilution water obtained in the second space 16 of the stage 1 membrane module 10 is stored in a dilution water tank through a pipe 92 as needed, and then discharged to the outside of the system.

The concentrated water obtained in the first space 14 of each membrane module of the 1 st stage membrane module unit 100a is fed to the first space 14 and the second space 16 of each membrane module of the 2 nd stage membrane module unit 100b through the pipe 90. In each membrane module of the 2 nd stage membrane module unit 100b, the first space 14 is pressurized, water contained in the first space 14 is transmitted to the second space 16 through the semipermeable membrane 12 (concentration step (2 nd stage)), and dilution water is obtained in the second space 16 (dilution step (2 nd stage)). The dilution water obtained in the second space 16 of each membrane module in the 2 nd stage membrane module unit 100b is stored in a dilution water tank through a pipe 96 as needed, and then discharged to the outside of the system.

The concentrated water obtained in the first space 14 of each membrane module of the 2 nd stage membrane module unit 100b is fed to the first space 14 and the second space 16 of each membrane module of the 3 rd stage membrane module unit 100c through the piping 94. In each membrane module of the 3 rd stage membrane module unit 100c, the first space 14 is pressurized, water contained in the first space 14 is transmitted to the second space 16 through the semipermeable membrane 12 (concentration step (3 rd stage)), and dilution water is obtained in the second space 16 (dilution step (3 rd stage)). The dilution water obtained in the second space 16 of each membrane module in the 3 rd stage membrane module unit 100c is stored in a dilution water tank through the pipe 102 as needed, and then discharged to the outside of the system.

The concentrated water obtained in the first space 14 of each membrane module of the 3 rd-stage membrane module unit 100c is fed to the first space 14 and the second space 16 of each membrane module of the 4 th-stage membrane module unit 100d through the piping 98. In each membrane module of the 4 th-stage membrane module unit 100d, the first space 14 is pressurized, and water contained in the first space 14 is transmitted to the second space 16 through the semipermeable membrane 12 (concentration step (4 th stage)), and dilution water is obtained in the second space 16 (dilution step (4 th stage)) (the above, the second recovery step). The concentrate obtained in the first space 14 of each membrane module in the 4 th-stage membrane module unit 100d is stored in the concentrate tank 86 through the pipe 104 as needed, and then discharged as a second recovered product. The dilution water obtained in the second space 16 of each membrane module in the 4 th-stage membrane module unit 100d is stored in a dilution water tank through a pipe 106 as needed, and then discharged to the outside of the system.

Here, the pump 18, the pipes 88, 90, 94, 98, and the like function as supply means for supplying distilled process water or concentrated water to the first space 14 and the second space 16 of each of the membrane modules of the membrane module units 100a, 100b, 100c, 100d of each stage.

The dilution water obtained in the second space 16 of each membrane module unit 100a, 100b, 100c, 100d of each stage may be discharged to the outside of the system, or may be fed to a dilution water tank to be stored as needed, and then discharged to the outside of the system, or may be reused. At least a part of the dilution water may be fed to the distilled water tank 84, and mixed with the distilled water in the distilled water tank 84. At least a part of the dilution water may be further treated with another treatment, for example, reverse osmosis membrane treatment as described below.

The water treatment apparatus 7 shown in fig. 7 includes a distillation apparatus 11 as a first recovery unit for recovering at least one of ammonia and ammonium ions from water containing ammonia as a first recovered product, and a second recovery unit for pressurizing the first space 14 of the semipermeable membrane module of the 1 st stage by using a semipermeable membrane module having a first space (concentrating side) 14 and a second space (permeate side) 16 separated by the semipermeable membrane 12, and passing distilled water from the distillation apparatus 11 through the first space 14 of the semipermeable membrane module of the 1 st stage, so that water contained in the distilled water permeates the semipermeable membrane 12, thereby obtaining concentrated water, and further using the semipermeable membrane module of the subsequent stage for the concentrated water, thereby obtaining at least a part of the concentrated water, and further passing at least a part of the diluted water from the other semipermeable membrane module, into the second space 16 of each stage, thereby obtaining diluted water. The 1 st-stage membrane module unit 100a includes, for example, 4 membrane modules connected in parallel, the 2 nd-stage membrane module unit 100b includes, for example, 4 membrane modules connected in parallel, the 3 rd-stage membrane module unit 100c includes, for example, 2 membrane modules connected in parallel, and the 4 th-stage membrane module unit 100d includes, for example, 2 membrane modules connected in parallel. Each membrane module 10 has a first space 14 and a second space 16 separated by a semi-permeable membrane 12. The water treatment apparatus 7 may be provided with a distilled water tank 84 for storing distilled water and a concentrated water tank 86 for storing concentrated water from the 4 th-stage membrane module unit 100 d. The membrane module unit 100 is a device that supplies distilled water to the first space of the membrane module of the 1 st stage, and sequentially supplies the concentrated water to the first space of the membrane module of the subsequent stage to perform concentration treatment.

In the water treatment apparatus 7 of fig. 7, a pipe 25 is connected to an inlet of the distillation apparatus 11. A pipe 27 is connected to the first recycle outlet of the distillation apparatus 11. The distilled water outlet of the distillation apparatus 11 is connected to the inlet of the distilled water tank 84 by a pipe 29. The outlet of the distillation treatment water tank 84 is connected to the first space inlet of each membrane module of the 1 st stage membrane module unit 100a via a pipe 108 by way of a pump 18. The first space outlet of each membrane module of the 1 st stage membrane module unit 100a and the first space inlet of each membrane module of the 2 nd stage membrane module unit 100b are connected by piping 110. The first space outlet of each membrane module of the 2 nd stage membrane module unit 100b is connected to the first space inlet of each membrane module of the 3 rd stage membrane module unit 100c by a pipe 112. The first space outlet of each membrane module of the 3 rd-stage membrane module unit 100c and the first space inlet of each membrane module of the 4 th-stage membrane module unit 100d are connected by piping 114. The first space outlet of each membrane module of the 4 th-stage membrane module unit 100d is connected to the inlet of the concentrate water tank 86 by a pipe 116. A piping 118 branched from the piping 116 is connected to the second space inlet of each membrane module of the 4 th-stage membrane module unit 100 d. The second space outlet of each membrane module of the 4 th-stage membrane module unit 100d is connected to the second space inlet of each membrane module of the 3 rd-stage membrane module unit 100c by piping 120. The second space outlet of each membrane module of the 3 rd-stage membrane module unit 100c is connected to the second space inlet of each membrane module of the 2 nd-stage membrane module unit 100b by piping 122. The second space outlet of each membrane module of the 2 nd stage membrane module unit 100b is connected to the second space inlet of each membrane module of the 1 st stage membrane module unit 100a by piping 124. A piping 126 is connected to the second space outlet of each membrane module of the stage 1 membrane module unit 100 a.

The membrane module unit 100 is the following: using a multistage membrane module unit including a membrane module 10 having a first space 14 and a second space 16 partitioned by a semipermeable membrane 12, distilled water is supplied to the first space of each membrane module of the 1 st stage membrane module unit, the concentrated water is sequentially supplied in series to the first space of each membrane module of the membrane module unit of the subsequent stage, at least a part of the concentrated water of each membrane module of the membrane module unit of the final stage is supplied to the second space thereof, the obtained diluted water is supplied in series to the second space 16 of each membrane module of the membrane module unit of the preceding stage thereof, and the first space 14 of each stage is pressurized, whereby the water contained in the first space 14 is concentrated by permeation through the semipermeable membrane 12 to the second space 16. That is, in the membrane module unit 100, the distilled water is concentrated using the semipermeable membrane 12, and the concentrated water is further concentrated using the semipermeable membrane 12 of the next stage.

In the water treatment apparatus 7, ammonia-containing water containing ammonia is supplied to the distillation apparatus 11 through a pipe 25. Distillation is performed in the distillation apparatus 11, and at least one of ammonia and ammonium ions is recovered as a first recovered product from water containing ammonia (first recovery step). The first recovered material is discharged through the pipe 27.

After the distilled water obtained by the distillation apparatus 11 is stored in the distilled water tank 84 as needed, the distilled water is fed from the distilled water tank 84 to the first space 14 of each membrane module of the 1 st stage membrane module unit 100a by the pump 18 through the pipe 108. On the other hand, the dilution water fed through the second space 16 of each membrane module of the 4 th-stage membrane module unit 100d, the second space 16 of each membrane module of the 3 rd-stage membrane module unit 100c, and the second space 16 of each membrane module of the 2 nd-stage membrane module unit 100b described later is fed to the second space 16 of each membrane module of the 1 st-stage membrane module unit 100a through the pipe 124. In each membrane module of the stage 1 membrane module unit 100a, the first space 14 is pressurized, water contained in the first space 14 permeates through the semipermeable membrane 12 to the second space 16 (concentration step (stage 1)), and dilution water is obtained in the second space 16 (dilution step (stage 1)). The concentrated water obtained in the first space 14 of each membrane module of the 1 st stage membrane module unit 100a is fed to the first space 14 of each membrane module of the 2 nd stage membrane module unit 100b through the pipe 110. The dilution water obtained in the second space 16 of each membrane module in the 1 st stage membrane module unit 100a is discharged to the outside of the system through the piping 126.

In each of the membrane modules of the 2 nd stage membrane module unit 100b, the dilution water fed through the second space 16 of each of the membrane modules of the 4 th stage membrane module unit 100d and the second space 16 of each of the membrane modules of the 3 rd stage membrane module unit 100c described later is fed to the second space 16 of each of the membrane modules of the 2 nd stage membrane module unit 100b through the piping 122. The first space 14 is pressurized, and the water contained in the first space 14 is transmitted through the semipermeable membrane 12 to the second space 16 (concentration step (2 nd stage)), and the dilution water is obtained in the second space 16 (dilution step (2 nd stage)). The concentrated water obtained in the first space 14 of each membrane module of the 2 nd stage membrane module unit 100b is fed to the first space 14 of each membrane module of the 3 rd stage membrane module unit 100c through the pipe 112. The dilution water obtained in the second space 16 of each membrane module of the 2 nd stage membrane module unit 100b is fed to the second space 16 of each membrane module of the 1 st stage membrane module unit 100a through the piping 124.

Of the membrane modules of the 3 rd membrane module unit 100c, the dilution water fed through the second space 16 of the membrane module of the 4 th membrane module unit 100d described later is fed to the second space 16 of the membrane module of the 3 rd membrane module unit 100c through the piping 120. The first space 14 is pressurized, and the water contained in the first space 14 is transmitted through the semipermeable membrane 12 to the second space 16 (concentration step (3 rd stage)), and the dilution water is obtained in the second space 16 (dilution step (3 rd stage)). The concentrated water obtained in the first space 14 of each membrane module of the 3 rd-stage membrane module unit 100c is fed to the first space 14 of each membrane module of the 4 th-stage membrane module unit 100d through the piping 114. The dilution water obtained in the second space 16 of each membrane module of the 3 rd-stage membrane module unit 100c is fed to the second space 16 of each membrane module of the 2 nd-stage membrane module unit 100b through the piping 122.

In each of the membrane modules of the 4 th-stage membrane module unit 100d, as described below, the concentrated water obtained in the first space 14 of each of the membrane modules of the 4 th-stage membrane module unit 100d is fed to the second space 16 through the pipes 116 and 118. The first space 14 is pressurized, and the water contained in the first space 14 is transmitted through the semipermeable membrane 12 to the second space 16 (concentration step (4 th step)), and the dilution water is obtained in the second space 16 (dilution step (4 th step)) (above, the second recovery step). The concentrate obtained in the first space 14 of each membrane module in the 4 th-stage membrane module unit 100d is stored in the concentrate tank 86 through the pipe 116 as needed, and then discharged as a second recovered product. The concentrated water branched from the piping 116 is fed to the second space 16 of each membrane module of the 4 th-stage membrane module unit 100d through the piping 118. The dilution water obtained in the second space 16 of each membrane module of the 4 th-stage membrane module unit 100d is fed to the second space 16 of each membrane module of the 3 rd-stage membrane module unit 100c through the piping 120.

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

The dilution water obtained in the second space 16 of each membrane module in the membrane module unit 100a may be discharged to the outside of the system, or may be fed to a dilution water tank as needed, stored, and then discharged to the outside of the system, or may be reused. At least a part of the dilution water may be fed to the distilled water tank 84, and mixed with the distilled water in the distilled water tank 84. At least a part of the dilution water may be further treated with another treatment, for example, reverse osmosis membrane treatment as described below.

In the case of supplying distilled water to each of the membrane modules of the 1 st-stage membrane module unit 100a, for example, a pressure of 7MPa or less is applied, and the concentrated water to the membrane module of the subsequent stage may be supplied by the pressure applied to each of the membrane modules of the 1 st-stage membrane module unit 100 a. The inlet pressure of the first space 14 in each membrane module is preferably in the range of 7MPa or less, the inlet pressure of the second space 16 is preferably a pressure smaller than the inlet pressure of the first space 14, and the inlet pressure of the second space 16 is more preferably 50% or less of the inlet pressure of the first space 14. This reduces the risk of breakage of the semipermeable membrane due to pressure.

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

If the permeation flux is too large, the concentration difference becomes large, and there is a problem that the risk of fouling becomes high and the pressure becomes too high. In addition, if the permeation flux is too small, the concentration efficiency may be deteriorated. From these viewpoints, the permeation flux of each membrane module 10 is preferably in the range of 0.005m/d to 0.05m/d, more preferably in the range of 0.015m/d to 0.04 m/d. For example, the pump 18 or the like functions as a permeation flux regulating unit that controls the permeation flux within the above-described range.

In addition, a valve may be provided in at least one of the pipes, and the position and the number of the valves may be not particularly limited. Further, at least one of the pipes may be provided with a flowmeter serving as a flow rate measuring means for measuring a flow rate and a pressure gauge serving as a pressure measuring means for measuring a pressure.

Fig. 6 and 7 show an example of the device configuration, and the number of stages, the number of parallel connections, the arrangement, the method of supplying the water, and the like of the semipermeable membrane modules may be appropriately changed.

In the membrane module, in order to concentrate the substance to be recovered in the distilled water as the second recovery product to a preferable concentration, the membrane module is preferably assembled in a plurality of stages in series. In the case of using a multistage membrane module like the water treatment apparatuses 3, 4, 5, 6, and 7, the number of stages of the membrane module may be determined according to the concentration of the target treated water or the like. For example, when it is desired to obtain a more concentrated treated water from a thinner concentrated distilled treated water, the number of stages of the membrane module unit may be increased.

In the case of using a membrane module unit having a plurality of membrane modules connected in parallel as each of the membrane modules in each stage as the water treatment apparatuses 6 and 7, the number of membrane modules in each membrane module unit may be determined according to the flow rate of distilled water or the like.

The membrane modules of 1 or more stages may be provided with a concentrate tank and a dilute tank, or the membrane modules of each stage may be provided with a concentrate tank and a dilute tank.

The ammonia-containing water as the water to be treated is not particularly limited as long as it is water containing ammonium ions. The ammonia-containing water is, for example, water containing sulfate ions and ammonium ions, and examples thereof include drainage discharged from a semiconductor factory, drainage discharged from a chemical factory, and the like. In particular, in a semiconductor factory, ammonia is used for cleaning wafers, and sulfuric acid is used for a scrubber process for treating ammonia. Thus, the wastewater contains ammonium ions and sulfate ions. Ammonia and sulfuric acid in the wastewater are recovered and reused as effective utilization of the wastewater.

The distillation apparatus 11 is not particularly limited as long as it is an apparatus capable of recovering ammonia from ammonia-containing water containing ammonia by distillation. Examples of the distillation apparatus 11 include a membrane distillation apparatus, a vacuum distillation apparatus, and the like that recover volatile ammonia through a gas permeable membrane. For example, ammonia recovered in the form of a gas by the distillation apparatus 11 may be added to sulfuric acid to produce ammonium sulfate for recovery. This enables recovery of ammonium sulfate having high purity.

Examples of the semipermeable membrane 12 included in the membrane module include semipermeable membranes 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 cellulose resins such as cellulose acetate resins, polysulfone resins such as polyether sulfone resins, polyamide resins, and the like.

Examples of the shape of the semipermeable membrane 12 include a flat membrane, a hollow fiber membrane, and a spiral membrane. Hollow fiber membranes are preferred in terms of increasing the surface area of the semipermeable membrane.

The second recovered product is a soluble solid component (TDS) contained in distilled water, and examples thereof include inorganic salts such as sodium sulfate, calcium sulfate, sodium chloride, and calcium chloride.

The water treatment method and the water treatment apparatus according to the present embodiment may include at least one pretreatment step (pretreatment unit) in the front stage of the first recovery step (first recovery unit), for example, a membrane treatment step (membrane treatment unit) using a microfiltration membrane (MF membrane), an ultrafiltration membrane (UF membrane), or the like, a reverse osmosis membrane treatment step (reverse osmosis membrane treatment unit), an flocculation precipitation treatment step (flocculation precipitation treatment unit), an organic matter removal treatment step (organic matter removal treatment unit), a pH adjustment step (pH adjustment unit), and a water temperature adjustment step (water temperature adjustment unit).

For example, pH adjustment and water temperature adjustment may be performed in order to efficiently recover a substance to be recovered by distillation in the front stage of the distillation apparatus 11. The pH of the water containing ammonia is preferably in the range of 10 to 12, and the water temperature is preferably in the range of 30 to 40℃although it depends on the water quality of the water containing ammonia, the concentration conditions of the first recovered product, and the like.

The pH adjustment and water temperature adjustment may be performed again before the water is introduced into the semipermeable membrane module at the rear stage of the distillation apparatus 11. The pH and water temperature during water passing in the semipermeable membrane component are determined according to the quality of ammonia-containing water, the material of the semipermeable membrane component and the like. For example, the pH of the water containing ammonia is preferably in the range of 3 to 8, and the water temperature is preferably in the range of 15 to 40 ℃.

The pH adjustment may be performed by adding a pH adjuster to a pH adjustment tank, for example. Examples of the pH adjuster include acids such as hydrochloric acid and sulfuric acid, and bases such as sodium hydroxide.

The water temperature adjustment may be performed by providing a water temperature adjustment tank, heating the water temperature adjustment tank with a heating device such as a heater, or by providing a heat exchanger.

The water treatment method and the water treatment apparatus according to the present embodiment may further include a water recovery step (water recovery means) of passing at least a part of the dilution water discharged from the second recovery step (second recovery means) through a reverse osmosis membrane to obtain permeate water, and a return step (return means) of returning the concentrate water discharged from the reverse osmosis membrane to a front stage of the semipermeable membrane module, after the second recovery step (second recovery means).

An example of a water treatment apparatus having such a structure is shown in fig. 8.

The water treatment apparatus 8 of fig. 8 includes, in addition to the configuration of the water treatment apparatus 1 of fig. 1, a reverse osmosis membrane treatment apparatus 200 as a water recovery means for passing at least a part of the dilution water discharged from the membrane module 10 to the reverse osmosis membrane to obtain permeate.

In the water treatment apparatus 8 of fig. 8, the second space outlet of the membrane module 10 is connected to the inlet of the reverse osmosis membrane treatment apparatus 200 by a pipe 30. A piping 202 is connected to the RO permeate outlet of the reverse osmosis membrane treatment apparatus 200. The concentrated water outlet of the RO of the reverse osmosis membrane treatment apparatus 200 and the upstream side of the pump 18 in the piping 24 are connected by piping 204 as a return unit. The other structures are the same as those of the water treatment apparatus 1 of fig. 1. In the water treatment apparatuses 2 to 7 of fig. 2 to 7, a reverse osmosis membrane treatment apparatus 200 and a piping 204 as a return means may be provided.

In the water treatment apparatus 8, the first recovery process and the second recovery process are performed in the same manner as the water treatment apparatus 1 of fig. 1. The diluted water obtained in the second space 16 of the membrane module 10 is sent to the reverse osmosis membrane treatment apparatus 200 through the piping 30. In the reverse osmosis membrane treatment apparatus 200, reverse osmosis membrane treatment is performed using a reverse osmosis membrane to obtain RO concentrated water and RO permeate water (water recovery step). The obtained RO permeate water is discharged to the outside of the system through the piping 202, and can be reused. The RO concentrated water is returned to the front stage of the membrane module 10, for example, to the pipe 24 through the pipe 204, and mixed with distilled water (return step). The RO concentrate may also be fed back to the front stage of the distillation apparatus 11 to be mixed with water containing ammonia.

As described above, at least one of ammonia and ammonium ions is recovered from the ammonia-containing water to be treated as a first recovered product, and further, the concentrated water in which the ions are concentrated is recovered as a second recovered product, thereby reducing the volume of the ammonia-containing water. The first recycle and the second recycle can be reused. Further, by subjecting the diluted water to reverse osmosis membrane treatment, water quality more suitable for reuse can be obtained. By returning the RO concentrate to the front section of the semipermeable membrane module, the amount of drainage can be reduced.

Symbol description

1. 2, 3, 4, 5, 6, 7, 8 water treatment devices,

10. 10a, 10b, 10c membrane modules,

11. a distillation device, wherein the distillation device comprises a distillation device body,

12. 12a, 12b, 12c semi-permeable membranes,

14. 14a, 14b, 14c,

16. 16a, 16b, 16c,

18. the pump is used for controlling the flow of air,

20. an inverter is provided with a first inverter and a second inverter,

22. 22a, 22b, 22c, 23, 32a, 32b, 32c,

24. 25, 26, 27, 28, 29, 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, 202, 204 tubing,

60a, 60b, 60c, 62a, 62b, 62c dilution tanks,

84. a water tank for distillation treatment,

86. a concentrated water tank, a water tank and a water tank,

100. 100a, 100b, 100c, 100d membrane module units,

200. reverse osmosis membrane treatment device.

Claims

1. A water treatment method for recovering valuable substances from water containing ammonia, characterized in that,

the water treatment method comprises the following steps:

a first recovery step of recovering ammonia gas from the ammonia-containing water by a distillation apparatus as a first recovered product; and

a second recovery step of introducing distilled water from the distillation apparatus into a first space and a second space separated by a semipermeable membrane, pressurizing the first space, allowing water contained in the distilled water to permeate the semipermeable membrane, thereby obtaining a second recovered product as concentrated water, introducing a part of the distilled water or at least a part of the concentrated water into the second space, thereby obtaining diluted water,

In the water treatment method, ammonia gas recovered as the first recycle is added to sulfuric acid to produce ammonium sulfate for recycling.

2. A water treatment method for recovering valuable substances from water containing ammonia, characterized in that,

the water treatment method comprises the following steps:

a second recovery step of introducing distilled water from the distillation apparatus into a first space of a semipermeable membrane module of a 1 st stage by using a semipermeable membrane module having a first space and a second space partitioned by a semipermeable membrane, pressurizing the first space to allow water contained in the distilled water to permeate the semipermeable membrane, thereby obtaining a second recovered product as concentrated water, introducing a part of the distilled water or at least a part of the concentrated water or at least a part of the dilution water obtained from other semipermeable membrane modules into a second space of the semipermeable membrane module of each stage,

3. The water treatment method according to claim 1 or 2, further comprising the steps of:

a water recovery step of passing at least a part of the dilution water discharged from the second recovery step to a reverse osmosis membrane after the second recovery step to obtain permeate water; and

and a return step of returning the concentrated water discharged from the reverse osmosis membrane to a front stage of the semipermeable membrane module.

4. A water treatment method according to any one of claim 1 to 3, wherein,

the concentration of sulfate ions in the water containing ammonia is 6000mg/L or more and the concentration of ammonium ions is 2000mg/L or more.

5. A water treatment apparatus for recovering valuable substances from water containing ammonia, characterized in that,

the water treatment device is provided with:

a first recovery unit that recovers ammonia gas from the ammonia-containing water as a first recovery product by a distillation device;

a second recovery unit that uses a semipermeable membrane module having a first space and a second space partitioned by a semipermeable membrane, that pressurizes the first space by passing distilled water of the distillation apparatus through the first space, that passes water contained in the distilled water through the semipermeable membrane, that obtains a second recovered product as concentrated water, and that passes water to the second space, that is, at least a part of the distilled water or at least a part of the concentrated water, to obtain dilution water; and

And a unit for adding the ammonia gas recovered as the first recovered product to sulfuric acid to produce ammonium sulfate and recovering the ammonium sulfate.

6. A water treatment apparatus for recovering valuable substances from water containing ammonia, characterized in that,

the water treatment device is provided with:

a second recovery unit that uses a semipermeable membrane module having a first space and a second space separated by a semipermeable membrane and connected in multiple stages, pressurizes the first space of the semipermeable membrane module of the 1 st stage by passing distilled water of the distillation apparatus through the first space, and passes water contained in the distilled water through the semipermeable membrane to obtain a second recovered product as concentrated water, and passes water of a part of the distilled water or at least a part of the concentrated water or at least a part of dilution water obtained from other semipermeable membrane modules to the second space of the semipermeable membrane module of each stage to obtain dilution water; and

7. A water treatment device according to claim 5 or 6, wherein,

the water treatment device further comprises:

a water recovery unit that, after the second recovery unit, passes at least a part of the dilution water discharged from the second recovery unit to a reverse osmosis membrane to obtain permeate water; and

a return unit that returns the concentrated water discharged from the reverse osmosis membrane to the front stage of the semipermeable membrane module.

8. A water treatment apparatus according to any one of claims 5 to 7, wherein,