WO2022024414A1

WO2022024414A1 - Ammonia concentration method and ammonia concentration device

Info

Publication number: WO2022024414A1
Application number: PCT/JP2021/002421
Authority: WO
Inventors: 優子梶原; 明広高田; 徹中野
Original assignee: オルガノ株式会社
Priority date: 2020-07-31
Filing date: 2021-01-25
Publication date: 2022-02-03
Also published as: CN116133737A; JP2022026961A; TW202216599A

Abstract

The present invention provides an ammonia concentration method and an ammonia concentration device, each of which is capable of suppressing biofouling, while maintaining the recovery rate of ammonia in a concentration process of water to be processed containing ammonia, said concentration process using a semipermeable membrane module that is provided with a cellulose acetate semipermeable membrane. An ammonia concentration method which comprises a semipermeable membrane processing step wherein, with use of a semipermeable membrane module that has a first space (16) and a second space (18) separated from each other by means of a cellulose acetate semipermeable membrane (14), ammonia concentrated water is obtained by flowing water to be processed containing ammonia into the first space (16) and applying a pressure to the first space (16), thereby causing water contained in the water to be processed to permeate through the semipermeable membrane (14), while dilute water is obtained by flowing some of the water to be processed or at least some of the ammonia concentrated water into the second space (18). With respect to this ammonia concentration method, the water to be processed is caused to contain a stabilized hypobromite composition that contains a bromine-based oxidant and a sulfamic acid compound.

Description

Ammonia concentration method and ammonia concentrator

The present invention relates to an ammonia concentrating method and an ammonia concentrating device for concentrating water to be treated containing ammonia.

A reverse osmosis method using a reverse osmosis membrane is known as a method for separating and concentrating ammonia from wastewater containing ammonia (see Patent Document 1). In addition, a method of concentrating water by passing water to be treated or its concentrated water through the first space and the second space partitioned by the semipermeable membrane of the semipermeable membrane module and pressurizing the first space is known. (See Patent Document 2). Such a concentration method using a semipermeable membrane concentrates wastewater at a high concentration with less energy consumption by reducing the osmotic pressure difference between the first space and the second space as compared with the general reverse osmosis method. can do.

Furthermore, in water treatment methods that use reverse osmosis membranes, it is common to use a disinfectant as a measure against biofouling. A typical bactericidal agent is a chlorine-based oxidant such as hypochlorous acid, which is usually added to the water to be treated before the reverse osmosis membrane treatment for the purpose of sterilization (see Patent Document 3).

When a chlorine-based oxidant such as hypochlorous acid is used as a disinfectant in the treatment of wastewater containing ammonia, the ammonia in the wastewater reacts with free chlorine derived from the disinfectant to generate bound chlorine, which has a bactericidal effect. May decrease. Therefore, in order to exert a sufficient bactericidal effect, it is necessary to increase the amount of the chlorine-based oxidant added as the ammonia concentration of the water to be treated becomes higher, which leads to an increase in cost.

On the other hand, when the purpose is to recover ammonia from ammonia-containing wastewater, when ammonia in the wastewater reacts with free chlorine, the amount of ammonia in the wastewater may decrease and the recovery rate of ammonia may decrease. .. Therefore, in order to increase the recovery rate of ammonia, it is necessary to suppress the amount of chlorine-based oxidizing agent added.

In addition, the chlorine-based oxidant may oxidatively deteriorate the polyamide-based semipermeable membrane, which is generally used as a semipermeable membrane, leading to deterioration of the treated water quality.

Japanese Unexamined Patent Publication No. 2012-125745 Japanese Unexamined Patent Publication No. 2018-069198 Japanese Patent No. 5978959

An object of the present invention is ammonia that can suppress biofouling while maintaining the recovery rate of ammonia in the concentration treatment of water to be treated using a semipermeable membrane module provided with a cellulose acetate semipermeable membrane. To provide a concentration method and an ammonia concentrator.

In the present invention, a semipermeable membrane module having a first space and a second space partitioned by a cellulose acetate-based semipermeable membrane is used to allow water to be treated containing ammonia to pass through the first space. The first space is pressurized to allow the water contained in the water to be treated to permeate through the semipermeable membrane to obtain concentrated ammonia water, and the second space is filled with a part of the water to be treated or the concentrated ammonia water. 2. This is an ammonia concentration method.

In the present invention, a semipermeable membrane module connected in multiple stages, which has a first space and a second space partitioned by a cellulose acetate-based semipermeable membrane, is used to apply ammonia-containing water to be treated in the first stage. Water is passed through the first space of the semipermeable membrane module of the above, and the first space is pressurized to allow the water contained in the water to be treated to permeate the semipermeable membrane to obtain ammonia-concentrated water, and the ammonia concentration thereof is obtained. A part of the water to be treated or at least a part of the ammonia-concentrated water is obtained in the second space of the semipermeable membrane module of each stage while water is further obtained by using the semipermeable membrane modules of the next and subsequent stages. A method for concentrating ammonia, which comprises a semipermeable membrane treatment step of passing water to obtain diluted water, and in which a stabilized hypobromic acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound is present in the water to be treated. be.

In the ammonia concentration method, it is preferable to further include a reverse osmosis membrane treatment step of performing a reverse osmosis membrane treatment on the diluted water to obtain RO permeated water and RO concentrated water.

In the ammonia concentration method, the stabilized hypobromous acid composition in the water to be treated so that the total chlorine concentration at at least one of the first space inlet and the first space outlet of the semipermeable membrane module becomes a predetermined value. It is preferable to adjust the amount of objects.

In the ammonia concentration method, the treated water containing ammonia is preferably at least one of ammonium sulfate-containing wastewater, ammonium fluoride-containing wastewater, and ammonium chloride-containing wastewater.

In the present invention, a semipermeable membrane module having a first space and a second space partitioned by a cellulose acetate-based semipermeable membrane is used to allow water to be treated containing ammonia to pass through the first space. The first space is pressurized to allow the water contained in the water to be treated to permeate through the semipermeable membrane to obtain concentrated ammonia water, and the second space is filled with a part of the water to be treated or the concentrated ammonia water. A semipermeable membrane treatment means for obtaining diluted water by passing at least a part of the above water, and an addition means for adding a stabilized hypobromic acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound to the water to be treated. It is an ammonia concentrator equipped with.

In the present invention, a semipermeable membrane module connected in multiple stages, which has a first space and a second space partitioned by a cellulose acetate-based semipermeable membrane, is used to apply ammonia-containing water to be treated in the first stage. Water is passed through the first space of the semipermeable membrane module of the above, and the first space is pressurized to allow the water contained in the water to be treated to permeate the semipermeable membrane to obtain ammonia-concentrated water, and the ammonia concentration thereof is obtained. A part of the water to be treated or at least a part of the ammonia-concentrated water is obtained in the second space of the semipermeable membrane module of each stage while water is further obtained by using the semipermeable membrane modules of the next and subsequent stages. A semipermeable membrane treatment means for obtaining diluted water by passing water through the water, and an addition means for adding a stabilized hypobromic acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound to the water to be treated are provided. , Ammonia concentrator.

It is preferable that the ammonia concentrator further includes a reverse osmosis membrane treatment means for performing a reverse osmosis membrane treatment on the diluted water to obtain RO permeated water and RO concentrated water.

In the ammonia concentrator, the total chlorine concentration measuring means for measuring the total chlorine concentration at at least one of the first space inlet and the first space outlet of the semipermeable membrane module, and the total measured by the total chlorine concentration measuring means. It is further preferable to further provide an adjusting means for adjusting the addition amount of the stabilized hypobromic acid composition by the adding means so that the chlorine concentration becomes a predetermined value.

In the ammonia concentrator, the water to be treated containing ammonia is preferably at least one of ammonium sulfate-containing wastewater, ammonium fluoride-containing wastewater, and ammonium chloride-containing wastewater.

INDUSTRIAL APPLICABILITY According to the present invention, in the concentration treatment of water to be treated containing ammonia using a semipermeable membrane module provided with a cellulose acetate semipermeable membrane, biofouling can be suppressed while maintaining the recovery rate of ammonia. And an ammonia concentrator can be provided.

It is a schematic block diagram which shows an example of the ammonia concentrator which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the ammonia concentrator which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the ammonia concentrator which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the ammonia concentrator which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the ammonia concentrator which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the ammonia concentrator which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the ammonia concentrator which concerns on embodiment of this invention. It is a schematic block diagram which shows the other example of the ammonia concentrator which concerns on embodiment of this invention. It is a schematic block diagram of the ammonia concentrator used in an Example.

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

<Ammonia concentration method and ammonia concentration device>
An outline of an example of the ammonia concentrator according to the embodiment of the present invention is shown in FIG. 1, and the configuration thereof will be described. In this specification, ammonia (NH ₃ ) and ammonium ion (NH ₄ ⁺ ) are collectively referred to as "ammonia".

The ammonia concentrator 1 shown in FIG. 1 contains ammonia by using a semipermeable membrane module having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane based on cellulose acetate. Water to be treated is passed through the first space, and the first space is pressurized to allow the water contained in the water to be treated to permeate through the semipermeable membrane to obtain concentrated ammonia water, and the water to be treated is passed through the second space. As a semipermeable membrane treatment means for obtaining diluted water by passing a part of the water, for example, a membrane module 12 is provided. The membrane module 12 has a first space 16 and a second space 18 partitioned by a semipermeable membrane 14. The ammonia concentrator 1 may include a water tank 10 to be treated to store water to be treated.

In the ammonia concentrator 1 shown in FIG. 1, a pipe 22 is connected to the water inlet of the water tank 10 to be treated. The outlet of the water tank 10 to be treated and the first space inlet of the membrane module 12 are connected by a pipe 24 via a pump 20, and the pipe 28 branched from the pipe 24 on the downstream side of the pump 20 in the pipe 24 is the membrane module 12. It is connected to the entrance of the second space. A pipe 26 is connected to the first space outlet of the membrane module 12, and a pipe 30 is connected to the second space outlet of the membrane module 12. A disinfectant addition pipe 32 is connected to the disinfectant inlet of the water tank 10 to be treated.

The ammonia concentrating device 1 of FIG. 1 uses a membrane module 12 having a first space 16 and a second space 18 partitioned by a semipermeable membrane 14, and allows water to be treated to flow from the entrance of the first space of the membrane module 12 to the first space. By passing water from the 16 and the entrance of the second space to the second space 18 and pressurizing the first space 16, the water contained in the water to be treated in the first space 16 is seconded through the semipermeable membrane 14. It is a device that concentrates the water to be treated by allowing it to permeate through the space 18. That is, in the ammonia concentrator 1, the water to be treated is concentrated using the semipermeable membrane 14. The ammonia concentrating device 1 is a device that supplies water to be treated to both the first space 16 and the second space 18 of the membrane module 12 to perform the concentrating treatment.

In the ammonia concentrator 1, the water to be treated containing ammonia is stored in the water tank 10 to be treated as needed through the pipe 22. Here, as a disinfectant, a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound is added to the water to be treated through the disinfectant addition pipe 32. The fungicide may be added in the pipe 22 or in the pipe 24. The water to be treated to which the disinfectant is added is pressurized and sent from the water tank 10 to be treated through the pipe 24 by the pump 20 from the inlet of the first space of the membrane module 12 to the first space 16 and passed through the water. Further, the water to be treated is sent from the second space inlet of the membrane module 12 to the second space 18 through the pipe 28 branched from the pipe 24, and is passed through the water. A part of the water contained in the pressurized water to be treated permeates from the first space 16 to the second space 18 through the semipermeable membrane 14. At this time, since most of the ammonia cannot pass through the semipermeable membrane 14, the ammonia in the first space 16 that did not pass through the semipermeable membrane 14 is concentrated. On the other hand, in the second space 18, a part of the water to be treated passed through the pipe 28 and the permeated water having a low ammonia concentration permeated through the semipermeable membrane 14 merge, so that the diluting effect works. The ammonia concentrated water obtained in the first space 16 is discharged from the first space outlet through the pipe 26, and the diluted water obtained in the second space 18 is discharged from the second space outlet through the pipe 30. Here, in the membrane module 12, the first space 16 is pressurized, and the water contained in the water to be treated in the first space 16 is permeated into the second space 18 via the semipermeable membrane 14, and the first space 16 is used. (Ammonia concentrated water is obtained) and diluted water is obtained in the second space 18 (diluting step).

Here, the pump 20, the

pipes

24, 28, etc. function as supply means for supplying the water to be treated to both the first space 16 and the second space 18 of the semipermeable membrane module 12.

The ammonia concentrated water obtained in the first space 16 may be recovered and reused. The ammonia-concentrated water obtained in the first space 16 may be further subjected to a distillation treatment or an electrodialysis treatment.

The diluted water obtained in the second space 18 may be discharged to the outside of the system through the pipe 30, or may be discharged to the diluted water tank as necessary, stored, and then discharged to the outside of the system. At least a part of the diluted water may be sent to the water tank 10 to be treated and mixed with the water to be treated in the water tank 10 to be treated. As will be described later, at least a part of the diluted water may be further sent to the reverse osmosis membrane treatment apparatus, and the reverse osmosis membrane treatment may be performed in the reverse osmosis membrane treatment apparatus (reverse osmosis membrane treatment step).

As described above, treated water containing ammonia (ammonia concentrated water) and diluted water are obtained from the water to be treated containing ammonia, which is the target of treatment, and the water to be treated containing ammonia is concentrated. Will be.

In the ammonia concentrating method and the ammonia concentrating device 1 according to the present embodiment, a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound as a bactericidal agent is present in the water to be treated containing ammonia, and is subjected to the subject. The treated water is passed through the first space 16 and the second space 18 of the membrane module 12. Thereby, in the concentration treatment of the water to be treated containing ammonia using the semipermeable membrane module provided with the cellulose acetate-based semipermeable membrane, biofouling can be suppressed while maintaining the recovery rate of ammonia.

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

The ammonia concentrator 2 shown in FIG. 2 contains ammonia by using a semipermeable membrane module having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane based on cellulose acetate. Water to be treated is passed through the first space, and the first space is pressurized to allow the water contained in the water to be treated to permeate through the semipermeable membrane to obtain concentrated ammonia water, and the second space is filled with concentrated ammonia water. As a semipermeable membrane treatment means for obtaining diluted water by passing at least a part of the above, for example, a membrane module 12 is provided. The membrane module 12 has a first space 16 and a second space 18 partitioned by a semipermeable membrane 14. The ammonia concentrator 2 may include a water tank 10 to be treated to store water to be treated.

In the ammonia concentrator 2 of FIG. 2, a pipe 22 is connected to the water inlet of the water tank 10 to be treated. The outlet of the water tank 10 to be treated and the first space inlet of the membrane module 12 are connected by a pipe 24 via a pump 20. A pipe 26 is connected to the first space outlet of the membrane module 12. The pipe 34 branched from the pipe 26 is connected to the second space entrance of the membrane module 12. A pipe 36 is connected to the second space outlet of the membrane module 12. A disinfectant addition pipe 32 is connected to the disinfectant inlet of the water tank 10 to be treated.

The ammonia concentrating device 2 of FIG. 2 uses a membrane module 12 having a first space 16 and a second space 18 partitioned by a semi-permeable membrane 14, and allows water to be treated to flow from the first space inlet of the membrane module 12 to the first space. At the same time as passing water through 16, at least a part of the ammonia-concentrated water discharged from the first space outlet of the first space 16 of the membrane module 12 is passed from the second space inlet of the membrane module 12 to the second space 18. By pressurizing the first space 16, the water contained in the water to be treated in the first space 16 is permeated into the second space 18 through the semi-permeable membrane 14, and the water to be treated is concentrated. That is, in the ammonia concentrator 2, the water to be treated is concentrated using the semipermeable membrane 14. The ammonia concentrating device 2 supplies water to be treated to the first space 16 of the membrane module 12, and supplies at least a part of the ammonia concentrated water obtained from the outlet of the first space 16 to the second space 18 of the membrane module 12. It is a device that performs concentration processing.

The ammonia concentrating method and the operation of the ammonia concentrating device 2 according to the present embodiment will be described.

In the ammonia concentrator 2, the water to be treated containing ammonia is stored in the water tank 10 to be treated as needed through the pipe 22. Here, as a disinfectant, a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound is added to the water to be treated through the disinfectant addition pipe 32. The fungicide may be added in the pipe 22 or in the pipe 24. The water to be treated to which the disinfectant is added is pressurized and sent from the water tank 10 to be treated through the pipe 24 by the pump 20 from the inlet of the first space of the membrane module 12 to the first space 16 and passed through the water. A part of the water contained in the pressurized water to be treated permeates from the first space 16 to the second space 18 through the semipermeable membrane 14. At this time, since most of the ammonia cannot pass through the semipermeable membrane 14, the ammonia in the first space 16 that did not pass through the semipermeable membrane 14 is concentrated. On the other hand, in the second space 18, at least a part of the ammonia concentrated water passed through the pipe 34 and the permeated water having a low ammonia concentration permeated through the semipermeable membrane 14 merge, so that the diluting effect works. The ammonia-concentrated water obtained in the first space 16 is discharged from the first space outlet through the pipe 26, and at least a part of the ammonia-concentrated water passes through the pipe 34 branched from the pipe 26 and enters the second space of the membrane module 12. Liquid is sent from to the second space 18 and water is passed through. The diluted water obtained in the second space 18 is discharged from the second space outlet through the pipe 36. Here, in the membrane module 12, the first space 16 is pressurized, and the water contained in the water to be treated in the first space 16 is permeated into the second space 18 via the semipermeable membrane 14, and the first space 16 is used. (Ammonia concentrated water is obtained) and diluted water is obtained in the second space 18 (diluting step).

Here, the pump 20,

pipes

24, 26, 34, etc. supply the water to be treated to the first space 16 of the semipermeable membrane module 12, and at least a part of the ammonia concentrated water obtained from the outlet of the first space 16. Functions as a supply means for supplying the second space 18 of the semipermeable membrane module 12.

The diluted water obtained in the second space 18 may be discharged to the outside of the system through the pipe 36, or may be discharged to the diluted water tank as necessary, stored, and then discharged to the outside of the system. At least a part of the diluted water may be sent to the water tank 10 to be treated and mixed with the water to be treated in the water tank 10 to be treated. As will be described later, at least a part of the diluted water may be further sent to the reverse osmosis membrane treatment apparatus, and the reverse osmosis membrane treatment may be performed in the reverse osmosis membrane treatment apparatus (reverse osmosis membrane treatment step).

In the ammonia concentrating method and the ammonia concentrating device 2 according to the present embodiment, a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound as a bactericidal agent is present in the water to be treated containing ammonia, and is subjected to the subject. The treated water is passed through the first space 16 of the membrane module 12, and the obtained concentrated ammonia water is passed through the second space 18. Thereby, in the concentration treatment of the water to be treated containing ammonia using the semipermeable membrane module provided with the cellulose acetate-based semipermeable membrane, biofouling can be suppressed while maintaining the recovery rate of ammonia.

In the ammonia concentrating method and the ammonia concentrating device according to the present embodiment, a multi-stage semipermeable membrane module connected in series may be used. FIG. 3 shows an example of an ammonia concentrator having such a configuration.

The ammonia concentrator 3 shown in FIG. 3 is a semipermeable membrane module connected in a plurality of stages and having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane based on cellulose acetate. The water to be treated containing ammonia is passed through the first space of the semipermeable membrane module of the first stage, and the first space is pressurized to allow the water contained in the water to be treated to permeate through the semipermeable membrane. To obtain concentrated ammonia water, and then use the semipermeable membrane modules of the next and subsequent stages to obtain concentrated ammonia water, and in the second space of the semipermeable membrane module of each stage, one of the water to be treated. As a semipermeable membrane processing means for obtaining diluted water by passing at least a part or at least a part of the ammonia concentrated water, for example, a first-stage membrane module 12a and a second-stage membrane module 12b are provided. Each membrane module has a first space 16 and a second space 18 partitioned by a semipermeable membrane 14. The ammonia concentrator 3 may include a water tank 10 to be treated to store water to be treated. The ammonia concentrating device 3 supplies water to be treated to the first space of the first-stage membrane module, sequentially supplies the ammonia-concentrated water to the first space of the next-stage membrane module, and the ammonia-concentrated water is the final stage. After passing through the first space of the semipermeable membrane module, at least a part of the ammonia concentrated water in the final stage is supplied to the second space of the semipermeable membrane module in the final stage, and the diluted water is sequentially supplied to the second space of the membrane module in the previous stage. It is a device that supplies to the space and performs concentration processing. In the ammonia concentrator 3, water to be treated is supplied to the first space and the second space of the first-stage membrane module, respectively, and the ammonia-concentrated water and the diluted water are sequentially supplied to the first space and the second space of the next-stage membrane module. It may be a device that supplies each of the spaces to perform the concentration treatment.

In the ammonia concentrator 3 shown in FIG. 3, a pipe 22 is connected to the water inlet of the water tank 10 to be treated. The outlet of the water tank 10 to be treated and the first space inlet of the first stage membrane module 12a are connected by a pipe 24 via a pump 20. The first space outlet of the first-stage membrane module 12a and the first space inlet of the second-stage membrane module 12b are connected by a pipe 38. A pipe 40 is connected to the first space outlet of the second stage membrane module 12b. The pipe 42 branched from the pipe 40 is connected to the second space entrance of the second stage membrane module 12b. The second space outlet of the second stage membrane module 12b and the second space inlet of the first stage membrane module 12a are connected by a pipe 44. A pipe 46 is connected to the second space outlet of the first-stage membrane module 12a. A disinfectant addition pipe 32 is connected to the disinfectant inlet of the water tank 10 to be treated.

The ammonia concentrator 3 uses a multi-stage membrane module having a first space 16 and a second space 18 partitioned by a semi-permeable membrane 14, and the water to be treated is serialized in the first space 16 of the multi-stage membrane module. At least a part of the ammonia concentrated water of the final stage membrane module is sent to the second space 18 of the final stage membrane module (second stage membrane module 12b in the example of FIG. 3), and finally. The diluted water of the membrane module of the stage is passed through the second space 18 of the membrane module of the previous stage in series, and the water contained in the first space 16 is transferred to the semitransparent membrane 14 by pressurizing the first space 16. It is a device that concentrates the water to be treated by allowing it to permeate through the second space 18. That is, in the ammonia concentrating device 3, the water to be treated is concentrated using the semipermeable membrane 14, and the ammonia concentrated water is further concentrated using the semipermeable membrane 14 of the next stage. Then, the ammonia-concentrated water that has passed through the first space 16 of the membrane module in the final stage is passed in series to the second space 18 of the membrane module in each stage, and the first space 16 of the membrane module in each stage is added. The water contained in the first space 16 is permeated through the second space 18 by pressing.

In the ammonia concentrator 3, the water to be treated containing ammonia is stored in the water tank 10 to be treated as needed through the pipe 22. Here, as a disinfectant, a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound is added to the water to be treated through the disinfectant addition pipe 32. The fungicide may be added in the pipe 22 or in the pipe 24. The water to be treated to which the disinfectant is added is pressurized and sent from the water tank 10 to be treated through the pipe 24 by the pump 20 from the inlet of the first space of the first stage membrane module 12a to the first space 16a, and is passed through the water. On the other hand, the diluted water sent through the second space 18b of the second stage membrane module 12b, which will be described later, is sent to the second space 18a of the first stage membrane module 12a through the pipe 44. In the first-stage membrane module 12a, the first space 16a is pressurized and the water contained in the first space 16a is permeated into the second space 18a (ammonia concentration step (first stage)), and the second space Diluted water is obtained at 18a (dilution step (first stage)). The diluted water obtained in the second space 18a is discharged from the second space outlet through the pipe 46.

The ammonia concentrated water obtained in the first space 16a of the first stage membrane module 12a is sent to the first space 16b of the second stage membrane module 12b through the pipe 38. The ammonia-concentrated water obtained in the first space 16b is discharged from the first space outlet through the pipe 40, and at least a part of the ammonia-concentrated water is passed through the pipe 42 branched from the pipe 40 to the second stage membrane module 12b. Liquid is sent from the entrance of the second space to the second space 18b, and water is passed therethrough. In the same manner as in the first stage, in the second stage membrane module 12b, the first space 16b is pressurized and the water contained in the first space 16b is permeated into the second space 18b (ammonia concentration step (second stage). Along with (eyes)), diluted water is obtained in the second space 18b (dilution step (second stage)). The diluted water obtained in the second space 18b is sent from the outlet of the second space to the second space 18a of the first stage membrane module 12a through the pipe 44.

Here, the pump 20,

pipes

24, 38, 40, 42, 44 and the like supply water to be treated to the first space 16 of the semipermeable membrane module 12, and the ammonia concentrated water obtained from the outlet of the first space 16. It functions as a supply means for supplying at least a part of the above to the second space 18 of the semipermeable membrane module 12.

The diluted water obtained in the second space 18 may be discharged to the outside of the system through the pipe 46, or may be discharged to the diluted water tank as necessary, stored, and then discharged to the outside of the system. At least a part of the diluted water may be sent to the water tank 10 to be treated and mixed with the water to be treated in the water tank 10 to be treated. As will be described later, at least a part of the diluted water may be further sent to the reverse osmosis membrane treatment apparatus, and the reverse osmosis membrane treatment may be performed in the reverse osmosis membrane treatment apparatus (reverse osmosis membrane treatment step).

In the ammonia concentrating method and the ammonia concentrating device 3 according to the present embodiment, a stabilized hypobromic acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound as a bactericidal agent is present in the water to be treated containing ammonia, and is subjected to the subject. The treated water is passed through the first space 16a of the multi-stage first-stage film module 12a, and the obtained ammonia-concentrated water is further passed through the first space 16 after the next-stage film module 12b to concentrate ammonia. While obtaining water, the obtained concentrated ammonia water is passed through the second space 18 of the membrane module 12 of each stage to obtain diluted water. As a result, in the concentration treatment of water to be treated containing ammonia using a multi-stage semipermeable membrane module connected in multiple stages equipped with a cellulose acetate-based semipermeable membrane, biofouling can be performed while maintaining the recovery rate of ammonia. It can be suppressed.

As described above, in the ammonia concentrating method and the ammonia concentrating device according to the present embodiment, at least a part of the diluted water may be further subjected to reverse osmosis membrane treatment. FIG. 4 shows an example of an ammonia concentrator having such a configuration.

In addition to the configuration of FIG. 3, the ammonia concentrator 4 shown in FIG. 4 further includes a reverse osmosis membrane treatment device 48 as a reverse osmosis membrane treatment means for performing reverse osmosis membrane treatment on at least a part of diluted water. In addition to the configuration of FIG. 1 or 2, a reverse osmosis membrane treatment apparatus 48 may be further provided as a reverse osmosis membrane treatment means for performing reverse osmosis membrane treatment on at least a part of the diluted water.

In the ammonia concentrator 4, the second space outlet of the first stage membrane module 12a and the inlet of the reverse osmosis membrane treatment device 48 are connected by a pipe 46. The RO permeated water pipe 50 is connected to the RO permeated water outlet of the reverse osmosis membrane treatment device 48, and the RO concentrated water pipe 52 is connected to the RO concentrated water outlet.

In the ammonia concentrator 4, the diluted water obtained in the second space 18a by performing the semipermeable membrane treatment in the same manner as in the ammonia concentrator 3 of FIG. 3 is a reverse osmosis membrane treatment device from the second space outlet through the pipe 46. The liquid is sent to 48. The reverse osmosis membrane treatment is performed in the reverse osmosis membrane treatment apparatus 48, and RO permeated water and RO concentrated water are obtained (reverse osmosis membrane treatment step). The RO permeated water is discharged through the RO permeated water pipe 50, and the RO concentrated water is discharged through the RO concentrated water pipe 52. The RO concentrated water may be sent to the water tank 10 to be treated and further subjected to a semipermeable membrane treatment to be concentrated.

In the ammonia concentrating method and the ammonia concentrating device 4 according to the present embodiment, ammonia can be further concentrated by further performing a reverse osmosis membrane treatment on the diluted water obtained by the semipermeable membrane treatment.

In the ammonia concentrating method and the ammonia concentrating device according to the present embodiment, a turbidifying film may be provided in front of the semipermeable membrane module. FIG. 5 shows an example of an ammonia concentrator having such a configuration.

In addition to the configuration of FIG. 3, the ammonia concentrating device 5 shown in FIG. 5 further includes a turbid film treatment device 56 as a turbid film treatment means for performing a turbid film treatment on the water to be treated. In addition to the configuration of FIG. 1, FIG. 2 or FIG. 4, a configuration may further include a decontamination film treatment device 56 as a decontamination film treatment means for performing the decontamination film treatment on the water to be treated.

In the ammonia concentrator 5, a pipe 22 is connected to the water inlet of the water tank 10 to be treated. The outlet of the water tank 10 to be treated and the inlet of the decontamination membrane treatment device 56 are connected by a pipe 64 via a pump 60. The decontamination membrane permeation water outlet of the decontamination membrane treatment device 56 and the inlet of the decontamination membrane permeation water tank 58 are connected by a pipe 66. A pipe 68 is connected to the decontamination membrane concentrated water outlet of the decontamination membrane treatment device 56. The outlet of the opaque membrane permeation water tank 58 and the first space inlet of the first stage membrane module 12a are connected by a pipe 70 via a pump 62. A disinfectant addition pipe 32 is connected to the disinfectant inlet of the water tank 10 to be treated.

In the ammonia concentrator 5, the water to be treated containing ammonia is stored in the water tank 10 to be treated as needed through the pipe 22. Here, as a disinfectant, a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound is added to the water to be treated through the disinfectant addition pipe 32. The fungicide may be added in the pipe 22 or in the pipe 64. The water to be treated to which the disinfectant is added is sent from the water tank 10 to be treated through the pipe 64 by the pump 60 to the decontamination membrane treatment device 56. The turbidating membrane treatment is performed in the turbidating membrane treatment apparatus 56, and the turbidating membrane permeated water and the turbidating membrane concentrated water are obtained (the turbidating membrane treatment step). The decontamination membrane permeation water is stored in the decontamination membrane permeation water tank 58 as needed through the pipe 66. The decontamination membrane concentrated water is discharged through the pipe 68. The opaque membrane permeated water is pressurized and sent from the opaque membrane permeated water tank 58 to the first space 16a from the first space inlet of the first stage membrane module 12a through the pipe 70 by the pump 62 as the water to be treated for the semipermeable membrane treatment. The liquid is passed through, and thereafter, the semipermeable membrane treatment is performed in the same manner as in the ammonia concentrating device 3 of FIG.

In the ammonia concentrator 5, both the sterilizing membrane treatment device 56 and the membrane module 12 can be sterilized by providing a sterilizing agent addition step in front of the sterilizing membrane, and biofouling of the sterilizing membrane and the semipermeable membrane. Can be suppressed together.

In the ammonia concentrating method and the ammonia concentrating device according to the present embodiment, stabilization of the water to be treated so that the total chlorine concentration at at least one of the first space inlet and the first space outlet of the semipermeable membrane module becomes a predetermined value. The amount of hypobromous acid composition may be adjusted. FIG. 6 shows an example of an ammonia concentrator having such a configuration.

In addition to the configuration of FIG. 1, the ammonia concentrator 6 shown in FIG. 6 is used as a total chlorine concentration measuring means for measuring the total chlorine concentration at at least one of the first space inlet and the first space outlet of the membrane module 12. A chlorine concentration measuring device 80 is further provided. The ammonia concentrator 6 may further include a control device 82 as a control means for controlling the addition of the stabilized hypobromous acid composition to the water to be treated. As a total chlorine concentration measuring means for measuring the total chlorine concentration at at least one of the first space inlet and the first space outlet of the membrane module 12, in addition to the configuration of FIG. 2, FIG. 3, FIG. 4 or FIG. The concentration measuring device 80 may be further provided.

In the ammonia concentrator 6, a total chlorine concentration measuring device 80 is installed in the pipe 26. Even if the control device 82 is connected to the total chlorine concentration measuring device 80 and the adjusting means (not shown) for adjusting the amount of the disinfectant added to the disinfectant addition pipe 32 by electrical connection or the like, respectively. good.

In the ammonia concentrator 6, the semipermeable membrane treatment is performed in the same manner as in the ammonia concentrator 1 of FIG. Here, in the pipe 26, the total chlorine concentration at the first space outlet of the membrane module 12 is measured by the total chlorine concentration measuring device 80 (total chlorine concentration measuring step). For example, by the control device 82, the flow rate of the pump installed in the sterilizing agent addition pipe 32 and the opening / closing degree of the valve are adjusted so that the total chlorine concentration in the ammonia concentrated water measured by the total chlorine concentration measuring device 80 becomes a predetermined value. Etc. may be adjusted, and the amount of the bactericidal agent added to the water to be treated may be adjusted (adjustment step). The amount of the disinfectant added may be automatically adjusted by the control device 82, or may be adjusted manually.

A total chlorine concentration measuring device 80 is installed in the pipe 24, and in the pipe 24, the total chlorine concentration at the first space inlet of the membrane module 12 is measured by the total chlorine concentration measuring device 80, and is measured by the total chlorine concentration measuring device 80. For example, the control device 82 adjusts the flow rate of the pump installed in the sterilizing agent addition pipe 32, the degree of opening and closing of the valve, and the like so that the total chlorine concentration in the water to be treated becomes a predetermined value, and then the water to be treated The amount of the bactericidal agent added may be adjusted. Further, a total chlorine concentration measuring device 80 is installed in the pipe 24 and the pipe 26, respectively, and in the pipe 24 and the pipe 26, the total chlorine in the first space inlet and the first space outlet of the membrane module 12 is provided by the total chlorine concentration measuring device 80. The concentration is measured, and the total chlorine concentration in the water to be treated and the concentrated ammonia water measured by the total chlorine concentration measuring device 80 is set to a predetermined value, for example, installed in the sterilizing agent addition pipe 32 by the control device 82. The flow rate of the pump, the degree of opening and closing of the valve, and the like may be adjusted, and the amount of the disinfectant added to the water to be treated may be adjusted. In order to confirm the sterilizing ability of the bactericide, at least the total chlorine concentration at the first space outlet of the membrane module 12 is measured, and the treatment is performed so that the total chlorine concentration in the ammonia-concentrated water at the first space outlet becomes a predetermined value. It is preferable that the amount of the bactericide added to the water is adjusted. For example, if the total chlorine concentration at the outlet of the first space is lower than the predetermined value, it is suggested that the amount of the disinfectant is insufficient and the risk of fouling is high. You can increase it. On the other hand, when the total chlorine concentration at the outlet of the first space is higher than a predetermined value, it is suggested that the disinfectant is excessively added, the chemical cost is high, and the risk of film deterioration is high. The amount of addition may be reduced. When a multi-stage semipermeable membrane module connected in series as shown in FIGS. 3 to 5 is used, the total chlorine concentration at the first space outlet of the final stage membrane module 12 is measured, and the final stage membrane module is measured. It is preferable that the amount of the bactericide added to the water to be treated is adjusted so that the total chlorine concentration in the ammonia-concentrated water at the first space outlet of 12 becomes a predetermined value.

The total chlorine concentration measuring device 80 may be any as long as it can measure the total chlorine concentration, and is not particularly limited. Examples of the method for measuring the total chlorine concentration include the DPD method.

The total chlorine concentration in the water to be treated and the concentrated ammonia water may be automatically measured by the total chlorine concentration measuring device 80, or may be measured manually.

The control device 82 includes, for example, a microcomputer including a calculation means such as a CPU for calculating a program, a storage means such as a ROM and a RAM for storing the program and the calculation result, and an electronic circuit, and is composed of total chlorine. Based on the total chlorine concentration measured by the concentration measuring device 80, the flow rate of the pump installed in the sterilizing agent addition pipe 32, the opening / closing degree of the valve, etc. are adjusted to control the amount of the sterilizing agent added to the water to be treated. It has a function to do.

When a multi-stage semipermeable membrane module connected in series is used in the ammonia concentration method and the ammonia concentrator according to the present embodiment, the water to be treated or the ammonia-concentrated water of the membrane module in the previous stage is used in the first space and the second space. Water may pass through. FIG. 7 shows an example of an ammonia concentrator having such a configuration. Further, the ammonia-concentrated water obtained in the first space of the membrane module may be passed through its own second space. FIG. 8 shows an example of an ammonia concentrator having such a configuration.

The ammonia concentrator 7 shown in FIG. 7 is a semipermeable membrane module connected in a plurality of stages and having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane based on cellulose acetate. The water to be treated containing ammonia is passed through the first space of the semipermeable membrane module of the first stage, and the first space is pressurized to allow the water contained in the water to be treated to permeate through the semipermeable membrane. To obtain concentrated ammonia water, and then use the semipermeable membrane modules of the next and subsequent stages to obtain concentrated ammonia water, and in the second space of the semipermeable membrane module of each stage, one of the water to be treated. As a semipermeable membrane processing means for obtaining diluted water by passing at least a part or at least a part of the ammonia concentrated water, for example, a first-stage membrane module 12a and a second-stage membrane module 12b are provided. Each membrane module has a first space 16 and a second space 18 partitioned by a semipermeable membrane 14. The ammonia concentrator 7 may include a water tank 10 to be treated to store water to be treated. The ammonia concentrator 7 supplies water to be treated to the first space and the second space of the first-stage membrane module, and sequentially supplies the ammonia-concentrated water to the first space and the second space of the next-stage membrane module. It is a device that performs concentration processing.

In the ammonia concentrator 7 shown in FIG. 7, a pipe 22 is connected to the water inlet of the water tank 10 to be treated. The outlet of the water tank 10 to be treated and the first space inlet of the first stage membrane module 12a are connected by a pipe 24 via a pump 20. The pipe 28 branched from the pipe 24 on the downstream side of the pump 20 in the pipe 24 is connected to the second space inlet of the first stage membrane module 12a. The first space outlet of the first-stage membrane module 12a and the first space inlet of the second-stage membrane module 12b are connected by a pipe 86. The pipe 88 branched from the pipe 86 is connected to the second space entrance of the second stage membrane module 12b. A pipe 84 is connected to the second space outlet of the first-stage membrane module 12a. A pipe 90 is connected to the first space outlet of the second stage membrane module 12b. A pipe 92 is connected to the second space outlet of the second stage membrane module 12b. A disinfectant addition pipe 32 is connected to the disinfectant inlet of the water tank 10 to be treated.

The ammonia concentrator 7 uses a multi-stage membrane module having a first space 16 and a second space 18 partitioned by a semipermeable membrane 14, and the water to be treated is serialized in the first space 16 of the multi-stage membrane module. At least a part of the water to be treated or the ammonia-concentrated water of the membrane module in the previous stage thereof is passed through the second space 18 of the membrane module of each stage, and the first space 16 is pressurized. It is a device that concentrates the water to be treated by allowing the water contained in the space 16 to permeate through the semipermeable membrane 14 into the second space 18. That is, in the ammonia concentrating device 7, the water to be treated is concentrated using the semipermeable membrane 14, and the ammonia concentrated water is further concentrated using the semipermeable membrane 14 of the next stage. Then, the ammonia-concentrated water that has passed through the first space 16 of the membrane module of each stage is passed through the second space 18 of the membrane module of the next stage, and the first space 16 of the membrane module of each stage is pressurized. The water contained in the first space 16 is allowed to permeate through the second space 18.

In the ammonia concentrator 7, the water to be treated containing ammonia is stored in the water tank 10 to be treated as needed through the pipe 22. Here, as a disinfectant, a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound is added to the water to be treated through the disinfectant addition pipe 32. The fungicide may be added in the pipe 22 or in the pipe 24. The water to be treated to which the disinfectant is added is pressurized and sent from the water tank 10 to be treated through the pipe 24 by the pump 20 from the inlet of the first space of the first stage membrane module 12a to the first space 16a, and is passed through the water. On the other hand, the water to be treated to which the disinfectant is added is sent to the second space 18a of the first stage membrane module 12a through the pipe 28 branched from the pipe 24. In the first-stage membrane module 12a, the first space 16a is pressurized and the water contained in the first space 16a is permeated into the second space 18a (ammonia concentration step (first stage)), and the second space Diluted water is obtained at 18a (dilution step (first stage)). The diluted water obtained in the second space 18a is discharged from the second space outlet through the pipe 84.

The ammonia concentrated water obtained in the first space 16a of the first stage membrane module 12a is sent to the first space 16b of the second stage membrane module 12b through the pipe 86. A part of the ammonia concentrated water obtained in the first space 16a is sent from the second space inlet of the second stage membrane module 12b to the second space 18b through the pipe 88 branched from the pipe 86, and is passed through the water. .. In the same manner as in the first stage, in the second stage membrane module 12b, the first space 16b is pressurized and the water contained in the first space 16b is permeated into the second space 18b (ammonia concentration step (second stage). Along with (eyes)), diluted water is obtained in the second space 18b (dilution step (second stage)). The ammonia-concentrated water obtained in the first space 16b is discharged from the first space outlet through the pipe 90. The diluted water obtained in the second space 18b is discharged from the second space outlet through the pipe 92.

Here, the pump 20, the

pipes

24, 28, 86, 88, etc. function as a supply means for supplying a part of the water to be treated or the concentrated ammonia water to the first space 16 and the second space 18 of the semipermeable membrane module 12. do.

The ammonia concentrator 8 shown in FIG. 8 is a semipermeable membrane module connected in a plurality of stages and having a first space (concentration side) and a second space (permeation side) partitioned by a semipermeable membrane based on cellulose acetate. The water to be treated containing ammonia is passed through the first space of the semipermeable membrane module of the first stage, and the first space is pressurized to allow the water contained in the water to be treated to permeate through the semipermeable membrane. Obtain concentrated water with ammonia, and then use the semipermeable membrane module of the next stage or later to obtain concentrated water with ammonia, and put a part of the concentrated water with ammonia into the second space of its own semipermeable membrane module. As a semipermeable membrane processing means for passing water to obtain diluted water, for example, a first-stage membrane module 12a and a second-stage membrane module 12b are provided. Each membrane module has a first space 16 and a second space 18 partitioned by a semipermeable membrane 14. The ammonia concentrator 8 may include a water tank 10 to be treated to store water to be treated. The ammonia concentrator 8 supplies water to be treated to the first space of the first-stage membrane module, sequentially supplies the ammonia-concentrated water to the first space of the next-stage membrane module, and is one of its own ammonia-concentrated water. It is a device that supplies the part to the second space and performs concentration processing.

In the ammonia concentrator 8 shown in FIG. 8, a pipe 22 is connected to the water inlet of the water tank 10 to be treated. The outlet of the water tank 10 to be treated and the first space inlet of the first stage membrane module 12a are connected by a pipe 24 via a pump 20. The first space outlet of the first-stage membrane module 12a and the first space inlet of the second-stage membrane module 12b are connected by a pipe 38. The pipe 94 branched from the pipe 38 is connected to the second space entrance of the first stage membrane module 12a. A pipe 46 is connected to the second space outlet of the first-stage membrane module 12a. A pipe 40 is connected to the first space outlet of the second stage membrane module 12b. The pipe 42 branched from the pipe 40 is connected to the second space entrance of the second stage membrane module 12b. A pipe 96 is connected to the second space outlet of the second stage membrane module 12b. A disinfectant addition pipe 32 is connected to the disinfectant inlet of the water tank 10 to be treated.

The ammonia concentrator 8 uses a multi-stage membrane module having a first space 16 and a second space 18 partitioned by a semi-permeable membrane 14, and water to be treated is serialized in the first space 16 of the multi-stage membrane module. By passing a part of the ammonia concentrated water through its own second space 18 and pressurizing the first space 16, the water contained in the first space 16 is passed through the semi-permeable membrane 14. It is a device that concentrates the water to be treated by allowing it to permeate through the two spaces 18. That is, in the ammonia concentrating device 8, the water to be treated is concentrated using the semipermeable membrane 14, and the ammonia concentrated water is further concentrated using the semipermeable membrane 14 of the next stage. Then, the ammonia-concentrated water that has passed through the first space 16 of the membrane module is passed through the second space 18 of its own membrane module, and the first space 16 of the membrane module of each stage is pressurized to press the first space 16 thereof. The water contained in the second space 18 is allowed to permeate through the second space 18.

In the ammonia concentrator 8, the water to be treated containing ammonia is stored in the water tank 10 to be treated as needed through the pipe 22. Here, as a disinfectant, a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound is added to the water to be treated through the disinfectant addition pipe 32. The fungicide may be added in the pipe 22 or in the pipe 24. The water to be treated to which the disinfectant is added is pressurized and sent from the water tank 10 to be treated through the pipe 24 by the pump 20 from the inlet of the first space of the first stage membrane module 12a to the first space 16a, and is passed through the water. On the other hand, the ammonia concentrated water obtained in the first space 16a of the first stage membrane module 12a is sent to the second space 18a of the first stage membrane module 12a through the pipe 94 branched from the pipe 38. In the first-stage membrane module 12a, the first space 16a is pressurized and the water contained in the first space 16a is permeated into the second space 18a (ammonia concentration step (first stage)), and the second space Diluted water is obtained at 18a (dilution step (first stage)). The diluted water obtained in the second space 18a is discharged from the second space outlet through the pipe 46.

The ammonia concentrated water obtained in the first space 16a of the first stage membrane module 12a is sent to the first space 16b of the second stage membrane module 12b through the pipe 38. The ammonia-concentrated water obtained in the first space 16b is discharged from the first space outlet through the pipe 40, and at least a part of the ammonia-concentrated water is passed through the pipe 42 branched from the pipe 40 to the second stage membrane module 12b. Liquid is sent from the entrance of the second space to the second space 18b, and water is passed therethrough. In the same manner as in the first stage, in the second stage membrane module 12b, the first space 16b is pressurized and the water contained in the first space 16b is permeated into the second space 18b (ammonia concentration step (second stage). Along with (eyes)), diluted water is obtained in the second space 18b (dilution step (second stage)). The diluted water obtained in the second space 18b is discharged through the pipe 96.

Here, the pump 20, the

pipes

24, 38, 40, 42, 94 and the like supply the water to be treated or the ammonia concentrated water to the first space 16 of the semipermeable membrane module 12, and are obtained from the outlet of the first space 16. It functions as a supply means for supplying at least a part of the concentrated aqueous ammonia to the second space 18 of the semipermeable membrane module 12.

When a multi-stage membrane module such as the

ammonia concentrator

3, 4, 5, 7, 8 is used, the number of stages of the membrane module may be determined by the ammonia concentration of the target treated water or the like. For example, when it is desired to obtain the treated water having a higher ammonia concentration from the treated water having a lower ammonia concentration, the number of stages of the membrane module unit may be increased.

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

In the ammonia concentrating method and the ammonia concentrating device according to the present embodiment, an ammonia concentrating water tank may be provided after the membrane module 12 in each stage. Further, a diluting water tank may be provided after the membrane module 12 in each stage.

The total chlorine concentration in contact with the semipermeable membrane is preferably in the range of 0.01 to 100 mg / L in terms of effective chlorine concentration, and more preferably in the range of 0.2 to 1.0 mg / L. If the total chlorine concentration in contact with the semipermeable membrane is less than 0.01 mg / L in terms of effective chlorine concentration, it may not be possible to obtain a sufficient bactericidal effect, and if it is more than 100 mg / L, it is based on cellulose acetate. Deterioration of the semipermeable membrane and corrosion of piping, etc. may occur.

The water to be treated may be water containing ammonia and is not particularly limited, but examples thereof include wastewater from semiconductor factories, wastewater from chemical factories, and domestic wastewater. Examples of the type of water to be treated include ammonium sulfate-containing wastewater, ammonium fluoride-containing wastewater, and ammonium chloride-containing wastewater. The method for concentrating ammonia according to the present embodiment is, for example, a method for treating ammonium sulfate-containing wastewater and concentrating ammonium sulfate.

The ammonia concentration in the water to be treated is not particularly limited, but is preferably 0.1 mg / L or more, more preferably 200 mg / L or more, and further preferably in the range of 5000 to 10000 mg / L. .. If the ammonia concentration in the water to be treated is less than 0.1 mg / L, the bactericide may decompose the ammonia and maintain a sufficient ammonia recovery rate. When the ammonia concentration is 200 mg / L or more, ammonia can be recovered with almost no decomposition regardless of the amount of the disinfectant added.

The ratio of the molar concentration of total chlorine to the molar concentration of ammonia during treatment is that if the total chlorine concentration is equal to or higher than the ammonia concentration, the recovery rate of ammonia may be low, so the molar concentration of total chlorine is the molar concentration of ammonia. It is preferably 0.1 times or less, more preferably 0.01 times or less with respect to the concentration.

By the ammonia concentrating method and the ammonia concentrating device according to the present embodiment, the ammonia concentration in the ammonia concentrated water can be concentrated to, for example, 10,000 mg / L or more, preferably 20,000 to 40,000 mg / L.

The pH of the water to be treated is, for example, in the range of 3 to 8, preferably in the range of 4 to 7. The lower limit of the pH of the water to be treated is preferably 5.5 or more, more preferably 6.0 or more, and even more preferably 6.5 or more. The upper limit of the pH of the water to be treated is preferably 8.0 or less, more preferably 7.5 or less.

The stabilized hypobromous acid composition contains a bromine-based oxidizing agent and a sulfamic acid compound. The "stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound" is a stabilized hypobromous acid composition containing a mixture of a "bromine-based oxidizing agent" and a "sulfamic acid compound". It may be a stabilized hypobromous acid composition containing "a reaction product of a bromine-based oxidizing agent and a sulfamic acid compound".

That is, in the ammonia concentration method according to the present embodiment, a mixture of, for example, a "bromine-based oxidizing agent" and a "sulfamic acid compound" is present in the water to be treated containing ammonia in the semipermeable membrane treatment. It is considered that this produces a stabilized hypobromous acid composition in the water to be treated.

Further, in the ammonia concentration method according to the present embodiment, a stabilized hypobromous acid composition which is, for example, "a reaction product of a bromine-based oxidizing agent and a sulfamic acid compound" in the water to be treated containing ammonia in the semipermeable membrane treatment. Make things exist.

Specifically, in the ammonia concentration method according to the present embodiment, in the water to be treated containing ammonia in the semitransparent film treatment, for example, "bromine", "bromine chloride", "hypobromous acid" or "sodium bromide" is used. A mixture of "reactant with hypochlorous acid" and "sulfamic acid compound" is present.

Further, in the ammonia concentration method according to the present embodiment, for example, "reaction product of bromine and sulfamic acid compound" and "reaction of bromine chloride and sulfamic acid compound" in the water to be treated containing ammonia in the semitransparent film treatment. Stabilization which is "product", "reaction product of hypobromous acid and sulfamic acid compound", or "reaction product of reaction product of sodium bromide and hypobromous acid and sulfamic acid compound". Hypobromous acid composition is present.

Although the stabilized hypobromous acid composition exhibits a bactericidal effect equal to or higher than that of a bactericidal agent such as a chlorine-based oxidant such as hypochlorous acid, it is compared with a bactericidal agent such as a chlorine-based oxidant. It is difficult to react with, and biofouling can be suppressed with a smaller amount of addition. Further, it is considered that the stabilized hypobromous acid composition has a smaller tendency of deterioration of the cellulose acetate-based semipermeable membrane than that of a bactericidal agent such as a chlorine-based oxidizing agent. Therefore, the stabilized hypobromous acid composition used in the ammonia concentration method according to the present embodiment is suitable as a bactericidal agent used for ammonia concentration in which a semipermeable membrane treatment is performed using a cellulose acetate-based semipermeable membrane. be.

Among the ammonia concentration methods according to the present embodiment, when the "bromine-based oxidant" is bromine, the effect of deterioration of the cellulose acetate-based semipermeable membrane is extremely low because the chlorine-based oxidant does not exist.

In the ammonia concentration method according to the present embodiment, for example, a "bromine-based oxidizing agent" and a "sulfamic acid compound" may be injected into the water to be treated containing ammonia in the semipermeable membrane treatment by a chemical injection pump or the like. The "bromine-based oxidizing agent" and the "sulfamic acid compound" may be added to the water to be treated separately, or the stock solutions may be mixed with each other and then added to the water to be treated.

Further, for example, "a reaction product of a bromine-based oxidizing agent and a sulfamic acid compound" may be injected into the water to be treated containing ammonia in the semipermeable membrane treatment by a chemical injection pump or the like.

The disinfectant may be added continuously to the water to be treated or intermittently.

In the stabilized hypobromous acid composition, the ratio of the equivalent of the "sulfamic acid compound" to the equivalent of the "bromine-based oxidizing agent" is preferably 1 or more, and more preferably 1 or more and 2 or less. .. If the ratio of the equivalent of the "sulfamic acid compound" to the equivalent of the "bromine-based oxidant" is less than 1, the cellulose acetate-based semipermeable membrane may be deteriorated, and if it exceeds 2, the production cost increases. In some cases.

Of these, the bactericides for "bromine and sulfamic acid compounds (mixtures of bromine and sulfamic acid compounds)" or "reaction products of bromine and sulfamic acid compounds" using bromine are "hypochlorite and bromine compounds". Compared with the bactericidal agent of "and sulfamic acid" and the bactericidal agent of "bromine chloride and sulfamic acid", the by-product of bromine acid is less, which is more preferable as a bactericidal agent.

Examples of the bromine-based oxidizing agent include bromine (liquid bromine), bromine chloride, bromic acid, bromate, hypobromous acid and the like. Hypobromous acid may be produced by reacting a bromine compound such as sodium bromide with a chlorine-based oxidizing agent such as hypochlorous acid.

Examples of the bromine compound include sodium bromide, potassium bromide, lithium bromide, ammonium bromide, hydrobromic acid and the like. Of these, sodium bromide is preferable from the viewpoint of formulation cost and the like.

The sulfamic acid compound is a compound represented by the following general formula (1).
R ₂ NSO ₃ H (1)
(In the formula, R is independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.)

Examples of the sulfamic acid compound include N-methylsulfamic acid, N-ethylsulfamic acid, N-propylsulfamic acid, and N-, in addition to sulfamic acid (amide sulfate) in which both of the two R groups are hydrogen atoms. Sulfamic acid compounds, N, N-dimethylsulfamic acid, N, where one of the two R groups such as isopropylsulfamic acid and N-butylsulfamic acid is a hydrogen atom and the other is an alkyl group having 1 to 8 carbon atoms. Two R groups such as N-diethylsulfamic acid, N, N-dipropylsulfamic acid, N, N-dibutylsulfamic acid, N-methyl-N-ethylsulfamic acid, N-methyl-N-propylsulfamic acid, etc. Sulfamic acid, one of which is a hydrogen atom and the other is an aryl group having 6 to 10 carbon atoms, such as a sulfamic acid compound and N-phenylsulfamic acid, both of which are alkyl groups having 1 to 8 carbon atoms. Examples include compounds and salts thereof. Examples of sulfamate include alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as calcium salt, strontium salt and barium salt, manganese salt, copper salt, zinc salt, iron salt and cobalt salt. Other metal salts such as nickel salts, ammonium salts, guanidine salts and the like can be mentioned. The sulfamic acid compound and salts thereof may be used alone or in combination of two or more. As the sulfamic acid compound, it is preferable to use sulfamic acid (amide sulfuric acid) from the viewpoint of environmental load and the like.

Alkali may be further present in the stabilized hypobromous acid composition in the water to be treated containing ammonia. Examples of the alkali include alkali hydroxides such as sodium hydroxide and potassium hydroxide. Sodium hydroxide and potassium hydroxide may be used in combination from the viewpoint of low temperature product stability and the like. Further, the alkali may be used as an aqueous solution instead of being solid.

The ammonia concentration method according to this embodiment can be suitably applied to a cellulose acetate-based polymer membrane as a semipermeable membrane. The cellulose acetate-based polymer membrane exhibits some resistance to chlorine-based oxidants, but continuous contact of free chlorine or the like with the cellulose acetate-based polymer membrane may cause deterioration of the membrane performance. However, when a stabilized hypobromous acid composition is used as a bactericide, it is considered that such a decrease in film performance hardly occurs even in a cellulose acetate-based polymer film.

<Fungicide for semipermeable membrane treatment>
The bactericidal agent for semipermeable membrane treatment used in the ammonia concentration method according to the present embodiment contains a stabilized hypobromous acid composition containing a "bromine-based oxidizing agent" and a "sulfamic acid compound", and further contains an alkali. It may be contained.

Further, the bactericidal agent for semitransparent film treatment used in the ammonia concentration method according to the present embodiment contains a stabilized hypobromous acid composition containing "a reaction product of a bromine-based oxidizing agent and a sulfamic acid compound". , Further may contain alkali.

The bromine-based oxidant, bromine compound, chlorine-based oxidant and sulfamic acid compound are as described above.

The stabilized hypobromous acid composition according to the present embodiment contains bromine and a sulfamic acid compound (a mixture of bromine and a sulfamic acid compound) so as not to further deteriorate the cellulose acetate-based semitransparent film. For example, a mixture of bromine and a sulfamic acid compound and an alkali and water, or a reaction product of bromine and a sulfamic acid compound, for example, a reaction product of bromine and a sulfamic acid compound. A mixture of alkali and water is preferred.

The stabilized hypobromous acid composition according to the present embodiment, particularly the stabilized hypobromous acid composition containing bromine and a sulfamic acid compound, reacts with ammonia as compared with a chlorine-based oxidizing agent such as hypochlorous acid. Although it is difficult to do so and has the effect of suppressing biofouling, it hardly causes remarkable deterioration of the cellulose acetate semitransparent film such as a chlorine-based oxidizing agent such as hypochlorous acid. At normal working concentrations, the effect on film deterioration is virtually negligible. Therefore, it is most suitable as a fungicide used for ammonia concentration for semipermeable membrane treatment.

Since the concentration of the stabilized hypobromous acid composition according to the present embodiment can be measured on-site in the same manner as hypochlorous acid and the like, more accurate concentration control is possible.

The pH of the stabilized hypobromous acid composition is, for example, more than 13.0, more preferably more than 13.2. When the pH of the stabilized hypobromous acid composition is 13.0 or less, the effective halogen in the stabilized hypobromous acid composition may become unstable.

The bromic acid concentration in the stabilized hypobromous acid composition is preferably less than 5 mg / kg. When the bromic acid concentration in the stabilized hypobromous acid composition is 5 mg / kg or more, the bromic acid ion concentration in the treated water may increase.

<Manufacturing method of fungicide for semipermeable membrane treatment>
The disinfectant for semipermeable membrane treatment used in the ammonia concentration method according to the present embodiment is obtained by mixing a bromine-based oxidizing agent and a sulfamic acid compound, and may be further mixed with an alkali.

As a method for producing a bactericidal agent for semitransparent film treatment containing bromine and a sulfamic acid compound, a step of adding bromine to a mixed solution containing water, an alkali and a sulfamic acid compound under an inert gas atmosphere, or a step of reacting the mixture or a reaction. It is preferable to include a step of adding bromine to a mixed solution containing water, an alkali and a sulfamic acid compound under an inert gas atmosphere. By adding and reacting in an inert gas atmosphere or by adding in an inert gas atmosphere, the concentration of bromate ion in the stabilized hypobromous acid composition is lowered.

The inert gas to be used is not limited, but at least one of nitrogen and argon is preferable from the viewpoint of production and the like, and nitrogen is particularly preferable from the viewpoint of production cost and the like.

The oxygen concentration in the reactor at the time of adding bromine is preferably 6% or less, more preferably 4% or less, further preferably 2% or less, and particularly preferably 1% or less. If the oxygen concentration in the reactor during the reaction of bromine exceeds 6%, the amount of bromic acid produced in the reaction system may increase.

The addition rate of bromine is preferably 25% by weight or less, more preferably 1% by weight or more and 20% by weight or less, based on the total amount of the stabilized hypobromous acid composition. When the addition rate of bromine exceeds 25% by weight based on the total amount of the stabilized hypobromous acid composition, the amount of bromic acid produced in the reaction system may increase. If it is less than 1% by weight, the bactericidal activity may be inferior.

The reaction temperature at the time of adding bromine is preferably controlled in the range of 0 ° C. or higher and 25 ° C. or lower, but more preferably controlled in the range of 0 ° C. or higher and 15 ° C. or lower from the viewpoint of manufacturing cost and the like. If the reaction temperature at the time of adding bromine exceeds 25 ° C, the amount of bromic acid produced in the reaction system may increase, and if it is less than 0 ° C, it may freeze.

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

[Preparation of stabilized hypobromous acid composition]
Liquid bromine: 16.9% by weight (wt%), sulfamic acid: 10.7% by weight, sodium hydroxide: 12.9% by weight, potassium hydroxide: 3.94% by weight, water: residue under a nitrogen atmosphere. The minutes were mixed to prepare a stabilized hypobromous acid composition. The pH of the stabilized hypobromous acid composition was 14, and the total chlorine concentration was 7.5% by weight. The total chlorine concentration is a value (mg-Cl ₂ / L) measured by a total chlorine measurement method (DPD (diethyl-p-phenylenediamine) method) using a multi-item water quality analyzer DR / 4000 manufactured by HACH. .. The detailed preparation method of the stabilized hypobromous acid composition is as follows.

To maintain the oxygen concentration in the reaction vessel at 1%, add 1436 g of water and 361 g of sodium hydroxide to a 2 L 4-port flask filled with continuous injection while controlling the flow rate of nitrogen gas with a mass flow controller. After mixing, add 300 g of sulfamic acid and mix, then add 473 g of liquid bromine and 230 g of 48% potassium hydroxide solution while maintaining cooling so that the temperature of the reaction solution becomes 0 to 15 ° C. The desired stabilized hypobromous acid composition, wherein the weight ratio of sulfamic acid to the total amount of the composition is 10.7%, bromine 16.9%, and the equivalent ratio of sulfamic acid to the equivalent of bromine is 1.04. Obtained. The pH of the resulting solution was 14 as measured by the glass electrode method. The bromine content of the resulting solution was 16.9% as measured by the method of converting bromine to iodine with potassium iodide and then using sodium thiosulfate for oxidative reduction titration, and the theoretical content (16.9%). ) Was 100.0%. The oxygen concentration in the reaction vessel during the bromine reaction was measured using "Oxygen Monitor JKO-02 LJDII" manufactured by Jiko Co., Ltd. The bromic acid concentration was less than 5 mg / kg.

The pH was measured under the following conditions.
Electrode type: Glass electrode type pH meter: Toa DKK, IOL-30 type Electrode calibration: Kanto Chemical Co., Ltd. Neutral phosphate pH (6.86) standard solution (Type 2), Borate manufactured by Kanto Chemical Co., Ltd. Measurement temperature performed by two-point calibration of salt pH (9.18) standard solution (type 2): 25 ° C.
Measured value: The electrode is immersed in the measuring solution, and the value after stabilization is used as the measured value, which is the average value of three measurements.

[Preparation of stabilized hypochlorous acid composition]
A composition was prepared by mixing 12% aqueous sodium hypochlorite solution: 50% by weight, sulfamic acid: 10% by weight, sodium hydroxide: 8% by weight, and water: residue. The pH of the composition was 14, and the total chlorine concentration was 6% by weight.

<Example 1>
Semipermeable membrane treatment was performed according to the flow shown in FIG. In the ammonia concentrator 9 shown in FIG. 9, the pipe 26 and the pipe 30 were connected to the water tank 10 to be treated, and the ammonia concentrated water and the diluted water were circulated in the water tank to be treated. As the semipermeable membrane module, "HP5255S3SI" manufactured by Toyobo Co., Ltd., which has a cellulose acetate-based semipermeable membrane, was used.

As the water to be treated, ammonium sulfate was added to pure water to prepare test water having an ammonia concentration of 10% by mass. The pump was started, and the water to be treated was passed 5 L / min to the first space of the semipermeable membrane module and 1.5 L / min to the second space to pressurize the first space. At this time, the ammonia concentrations of the water to be treated, the ammonia concentrated water, and the diluted water were measured by the methods shown below. The results are shown in Table 1.

The ammonia concentration of the ammonia concentrated water with respect to the water to be treated was 1.25 times. By passing water containing ammonia through the semipermeable membrane module and pressurizing it in this way, ammonia could be concentrated.

<Example 2>
[Sterilization test]
As the water to be treated, ammonium chloride was added to the bouillon solution so that the ammonia concentration was 0 mg / L, 0.1 mg / L, 1 mg / L, 10 mg / L, and 100 mg / L to prepare test water. Further, the stabilized hypobromous acid composition was added as a bactericide so that the total chlorine concentration was 1 mg / L. The ratios of the molar concentration of total chlorine to the molar concentration of ammonia are 0, 2.5, 0.25, 0.025 and 0.0025, respectively. The prepared solution was allowed to stand at 25 ° C. for 3 hours. The viable cell count and ammonia concentration were measured before and after the test. The results are shown in Table 2.

The total chlorine concentration was measured by an effective chlorine measurement method (DPD (diethyl-p-phenylenediamine) method) using a pocket residual chlorine meter manufactured by HACH and a total chlorine reagent (HACH0582).

For the viable cell count measurement, a plate for measuring the viable cell count of Petrifilm (manufactured by 3M Healthcare) was used. The film was inoculated with 1 mL of the sample and cultured at 35 ° C. for 48 hours. The number of colonies growing on the film was measured after 48 hours.

Ammonia concentration was measured by an ion chromatograph method using an ion chromatograph (IntegrationRFIC manufactured by Thermo Fisher).

<Comparative Example 1>
As the water to be treated, ammonium chloride was added to the bouillon solution so that the ammonia concentration was 0 mg / L, 0.1 mg / L, 1 mg / L, 10 mg / L, and 100 mg / L to prepare test water. Further, sodium hypochlorite was added as a bactericidal agent so that the total chlorine concentration became 1 mg / L. The ratios of the molar concentration of total chlorine to the molar concentration of ammonia are 0, 2.5, 0.25, 0.025 and 0.0025, respectively. The prepared solution was allowed to stand at 25 ° C. for 3 hours. The viable cell count and ammonia concentration were measured before and after the test. The results are shown in Table 2.

<Comparative Example 2>
As the water to be treated, ammonium chloride was added to the bouillon solution so that the ammonia concentration was 0 mg / L, 0.1 mg / L, 1 mg / L, 10 mg / L, and 100 mg / L to prepare test water. Further, the stabilized hypochlorous acid composition containing a chlorine-based oxidizing agent (sodium hypochlorite) and a sulfamic acid compound was added as a bactericidal agent so that the total chlorine concentration was 1 mg / L. The ratios of the molar concentration of total chlorine to the molar concentration of ammonia are 0, 2.5, 0.25, 0.025 and 0.0025, respectively. The prepared solution was allowed to stand at 25 ° C. for 3 hours. The viable cell count and ammonia concentration were measured before and after the test. The results are shown in Table 2.

Table 2 shows the viable cell count and ammonia concentration before and after the test under each condition. As described above, in the case of the bactericidal agent containing the bromine-based oxidizing agent and the sulfamic acid compound, the viable cell count hardly increased even if the ammonia concentration increased, and the bactericidal ability could be maintained. Further, when the ammonia concentration was 1 mg / L or more, the residual rate of ammonia was 80% or more, which was a high value.

On the other hand, in the case of sodium hypochlorite, when the ammonia concentration was 1 mg / L, a high ammonia residual rate was shown, but when the ammonia concentration was 100 mg / L, the viable cell count was compared with when the ammonia concentration was 0 mg / L. Increased about 1.6 times, and the bactericidal activity decreased.

In the case of a bactericidal agent containing a chlorine-based oxidant and a sulfamic acid compound, the ammonia concentration was maintained, but the bactericidal activity was weak, and the bacteria in the sample water were hardly sterilized.

From the results of Example 2 and Comparative Examples 1 and 2, when the fungicide containing the bromine-based oxidizing agent and the sulfamic acid compound had the same amount of the fungicide added, the highest fungicide ability was shown while leaving ammonia.

As described above, in the concentration treatment of the water to be treated containing ammonia using the semipermeable membrane module provided with the cellulose acetate-based semipermeable membrane, the stabilized hypobromous acid composition is present in the water to be treated to obtain the ammonia. It was found that biofouling can be suppressed while maintaining the recovery rate.

1,2,3,4,5,6,7,8,9 Ammonia concentrator, 10 Water tank to be treated, 12 membrane module, 12a 1st stage membrane module, 12b 2nd stage membrane module, 14, 14a, 14b and a half Transparent membrane, 16, 16a, 16b first space, 18, 18a, 18b second space, 20, 60, 62 pump, 22, 24, 26, 28, 30, 34, 36, 38, 40, 42, 44, 46,64,66,68,70,84,86,88,90,92,94,96 piping, 32 sterilizing agent addition piping, 48 reverse osmosis membrane treatment device, 50 RO permeable water piping, 52 RO concentrated water piping, 56 Decontamination membrane treatment device, 58 Decontamination membrane permeation water tank, 80 Total chlorine concentration measuring device, 82 Control device.

Claims

Using a semi-permeable membrane module having a first space and a second space partitioned by a cellulose acetate-based semi-permeable film, water to be treated containing ammonia is passed through the first space, and the first space is passed through. An ammonia-concentrated water is obtained by pressurizing the water contained in the water to be treated to permeate the semi-permeable film, and at the same time, a part of the water to be treated or at least a part of the ammonia-concentrated water is formed in the second space. Including a semi-transmissive treatment step of passing water to obtain diluted water,
A method for concentrating ammonia, which comprises allowing a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound to be present in the water to be treated.
Using a semipermeable membrane module connected in multiple stages, which has a first space and a second space separated by a cellulose acetate-based semipermeable membrane, the water to be treated containing ammonia is transferred to the first stage semipermeable membrane. Water is passed through the first space of the module, the first space is pressurized, and the water contained in the water to be treated is permeated through the semipermeable membrane to obtain ammonia-concentrated water, and the ammonia-concentrated water is further next. A semipermeable membrane module after the stage is used to obtain concentrated water for ammonia, and a part of the water to be treated or at least a part of the concentrated water for ammonia is passed through the second space of the semipermeable membrane module of each stage. Includes a semipermeable membrane treatment step to obtain diluted water
A method for concentrating ammonia, which comprises allowing a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound to be present in the water to be treated.
The method for concentrating ammonia according to claim 1 or 2.
A method for concentrating ammonia, further comprising a reverse osmosis membrane treatment step of performing a reverse osmosis membrane treatment on the diluted water to obtain RO permeated water and RO concentrated water.
The method for concentrating ammonia according to any one of claims 1 to 3.
The amount of the stabilized hypobromous acid composition in the water to be treated is adjusted so that the total chlorine concentration at at least one of the first space inlet and the first space outlet of the semipermeable membrane module becomes a predetermined value. Ammonia concentration method characterized by that.
The method for concentrating ammonia according to any one of claims 1 to 4.
The method for concentrating ammonia, wherein the water to be treated containing ammonia is at least one of ammonium sulfate-containing wastewater, ammonium fluoride-containing wastewater, and ammonium chloride-containing wastewater.
Using a semi-permeable membrane module having a first space and a second space partitioned by a cellulose acetate-based semi-permeable film, water to be treated containing ammonia is passed through the first space, and the first space is passed through. An ammonia-concentrated water is obtained by pressurizing the water contained in the water to be treated to permeate the semi-permeable film, and at the same time, a part of the water to be treated or at least a part of the ammonia-concentrated water is formed in the second space. Semi-transmissive treatment means to obtain diluted water by passing water,
An addition means for adding a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound to the water to be treated.
Ammonia concentrator, characterized in that it comprises.
Using a semipermeable membrane module connected in multiple stages, which has a first space and a second space separated by a cellulose acetate-based semipermeable membrane, the water to be treated containing ammonia is transferred to the first stage semipermeable membrane. Water is passed through the first space of the module, the first space is pressurized, and the water contained in the water to be treated is permeated through the semipermeable membrane to obtain ammonia-concentrated water, and the ammonia-concentrated water is further next. A semipermeable membrane module after the stage is used to obtain concentrated ammonia water, and a part of the water to be treated or at least a part of the concentrated ammonia water is passed through the second space of the semipermeable membrane module of each stage. Semipermeable membrane treatment means to obtain diluted water, and
An addition means for adding a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound to the water to be treated.
Ammonia concentrator, characterized in that it comprises.
The ammonia concentrator according to claim 6 or 7.
An ammonia concentrating device further comprising a reverse osmosis membrane treating means for performing a reverse osmosis membrane treatment on the diluted water to obtain RO permeated water and RO concentrated water.
The ammonia concentrator according to any one of claims 6 to 8.
A total chlorine concentration measuring means for measuring the total chlorine concentration at at least one of the first space inlet and the first space outlet of the semipermeable membrane module, and
An adjusting means for adjusting the addition amount of the stabilized hypobromous acid composition by the addition means so that the total chlorine concentration measured by the total chlorine concentration measuring means becomes a predetermined value.
Ammonia concentrator, characterized in that it further comprises.
The ammonia concentrator according to any one of claims 6 to 9.
The ammonia concentrating device, wherein the treated water containing ammonia is at least one of ammonium sulfate-containing wastewater, ammonium fluoride-containing wastewater, and ammonium chloride-containing wastewater.