JP2017217607A - Water treatment method and apparatus, method for remodeling water treatment apparatus, and kit for remodeling water treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water treatment method which includes concentrating ammonia contained in water to be treated in a regeneration waste liquid of a cation exchange resin, and ammonia stripping the regeneration waste liquid, where an amount of alkali to be added at the time of the ammonia stripping can be suppressed.SOLUTION: A water treatment method includes: an ion exchange step of passing water to be treated in which ammonia is dissolved through a cation exchange resin and an anion exchange resin; a regeneration waste liquid mixing step of mixing a regeneration waste liquid obtained by regenerating the cation exchange resin and a regeneration waste liquid obtained by regenerating the anion exchange resin; and a stripping step of removing ammonia from the mixed regeneration waste liquid by stripping the mixed regeneration waste liquid on an alkaline condition. A water treatment apparatus is suitable for performing the method. A method for remodeling the water treatment apparatus and a kit for remodeling the water treatment apparatus obtain the apparatus.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a water treatment method and apparatus for removing ammonia from ammonia-containing water, such as ammonia-containing wastewater discharged from a manufacturing process of an electronic product such as a semiconductor or liquid crystal or an element thereof.

  In the semiconductor manufacturing process and related processes, cleaning is performed using a chemical in which ammonia and hydrogen peroxide are mixed. After the cleaning step, cleaning is performed using ultrapure water to remove ammonia remaining on the surface of the article to be cleaned. For this reason, a large amount of wastewater having a low salt concentration and a relatively low concentration of ammonia is discharged. Since ammonia is a cause of eutrophication, it is necessary to treat ammonia in the wastewater. In addition, since a large amount of ultrapure water is required in the cleaning process, it is desirable to collect and reuse wastewater.

  Conventionally, an ammonia stripping method is known as a method for treating ammonia-containing wastewater. In this method, ammonia-containing wastewater is heated with steam, a heater, or the like, and diffused in a diffusion tower. When performing the stripping process, it is advantageous that the ammonia concentration is high in terms of processing cost. Therefore, a method in which ammonia contained in low-concentration ammonia-containing waste water is adsorbed on a cation exchange resin, and then the cation exchange resin is regenerated to obtain a regenerated waste liquid in which ammonia is concentrated, and the regenerated waste liquid is ammonia stripped to remove ammonia. (Patent Document 1). By contacting the exhaust gas discharged from the diffusion tower with an ammonia decomposition catalyst, the ammonia can be removed by oxidative decomposition (Patent Document 2).

Japanese Examined Patent Publication No. 56-042360 JP 2003-340440 A

  The cation exchange resin is regenerated with acid. Therefore, the pH of the recycled waste liquid is acidic. On the other hand, in ammonia stripping, in order to volatilize ammonia, it is necessary to adjust the pH of the liquid to be diffused to alkaline and pass the water through the stripping tower. Therefore, when ammonia stripping is performed on the regeneration waste liquid of the cation exchange resin, a large amount of alkali is required for alkalinization.

  An object of the present invention is to reduce the amount of alkali added during ammonia stripping in a water treatment method in which ammonia contained in water to be treated is concentrated in a cation exchange resin regeneration waste liquid and the regeneration waste liquid is ammonia stripped. It is to provide a method that can be used.

  Another object of the present invention is to provide a water treatment apparatus suitable for carrying out this water treatment method.

  A further object of the present invention is to provide a water treatment device remodeling method and a water treatment device remodeling kit for obtaining the water treatment device.

According to one aspect of the invention,
An ion exchange step of passing water to be treated in which ammonia is dissolved through a cation exchange resin and an anion exchange resin;
A regeneration waste liquid mixing step of mixing a regeneration waste liquid obtained by regenerating the cation exchange resin and a regeneration waste liquid obtained by regenerating the anion exchange resin; and
There is provided a water treatment method including a stripping step in which ammonia is removed from the mixed recycled waste liquid by stripping the mixed recycled waste liquid under alkaline conditions.

According to another aspect of the invention,
An ion exchange resin tower comprising a cation exchange resin and an anion exchange resin,
A mixing device connected to the cation exchange resin regeneration waste liquid outlet and the anion exchange resin regeneration waste liquid outlet of the ion exchange resin tower; and
A water treatment device is provided that includes a stripping tower connected to the outlet of the mixing device.

According to a further aspect of the invention,
A method for remodeling a water treatment apparatus including a cation exchange resin tower containing a cation exchange resin,
An anion exchange resin tower comprising an anion exchange resin, arranged in series with the cation resin tower with respect to the water to be treated;
A mixing device connected to the cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower and the anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower; and
A method for retrofitting a water treatment device is provided, comprising providing a stripping tower connected to the outlet of the mixing device.

According to a further aspect of the invention,
A kit for remodeling a water treatment apparatus including a cation exchange resin tower including a cation exchange resin,
An anion exchange resin tower comprising an anion exchange resin, arranged in series with the cation resin tower with respect to the water to be treated;
A mixing device connected to the cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower and the anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower; and
A water treatment device retrofit kit is provided that includes a stripping tower connected to the outlet of the mixing device.

According to a further aspect of the invention,
A method for remodeling a water treatment apparatus comprising: a cation exchange resin tower containing a cation exchange resin; and a diffusion tower connected to a cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower,
An anion exchange resin tower comprising an anion exchange resin, arranged in series with the cation resin tower with respect to the water to be treated; and
A cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower and an anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower, wherein the outlet of the mixing apparatus is connected to the diffusion tower. A method for retrofitting a water treatment device is provided that includes providing a mixing device.

According to a further aspect of the invention,
A kit for remodeling a water treatment apparatus comprising a cation exchange resin tower containing a cation exchange resin, and a diffusion tower connected to a cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower,
An anion exchange resin tower comprising an anion exchange resin, arranged in series with the cation resin tower with respect to the water to be treated; and
A cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower and an anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower, wherein the outlet of the mixing apparatus is connected to the diffusion tower. A water treatment device retrofit kit including a mixing device is provided.

  According to the present invention, in the water treatment method of concentrating ammonia contained in the water to be treated into the cation exchange resin regeneration waste liquid, and stripping the regeneration waste liquid with ammonia, the amount of alkali added during ammonia stripping is suppressed. A method is provided.

  Moreover, according to this invention, the water treatment apparatus suitable for implementing this water treatment method is provided.

  Furthermore, according to this invention, the modification method of the water treatment apparatus and the kit for water treatment apparatus modification for obtaining this water treatment apparatus are provided.

It is a process flow diagram which shows an example of the water treatment apparatus of this invention. It is a process flow diagram which shows an example of the existing water treatment apparatus which is going to remodel. It is a process flow diagram which shows another example of the existing water treatment apparatus which it is going to remodel.

  The water treatment method according to the present invention includes an ion exchange step, a regeneration waste liquid mixing step, and a stripping step.

[Ion exchange process]
The water to be treated is water in which ammonia is dissolved, for example, ammonia-containing wastewater discharged from an electronic product manufacturing process. Since a part of ammonia dissolved in water becomes ammonium ions, the water to be treated contains ammonium ions.

  It is preferable that the ammonia concentration in the water to be treated is about 10 mg / L or more and 200 mg / L or less because the effect of the present invention is particularly remarkable.

  Unless otherwise specified, “ammonia concentration” in the liquid in this specification means a concentration including not only free ammonia but also ammonium ions. Unless otherwise specified, when the ammonia concentration in the liquid is expressed in the unit of “mg / L”, it means the concentration when free ammonia and ammonium ions are converted to nitrogen.

  In this step, water to be treated is passed through a cation exchange resin (cation exchange resin that adsorbs cations) and an anion exchange resin (anion exchange resin that adsorbs anions). The order of the treatment with the cation exchange resin and the treatment with the anion exchange resin is not limited. For example, water to be treated can be passed through a cation exchange resin and then through an anion exchange resin. Alternatively, the water to be treated can be passed through an anion exchange resin and then through a cation exchange resin. A mixed bed of a cation exchange resin and an anion exchange resin can also be used.

  When the water to be treated is passed through the cation exchange resin, cations such as ammonium ions, calcium ions, and magnesium ions are adsorbed on the cation exchange resin. When the water to be treated is passed through the anion exchange resin, anions such as chloride ions, nitrate ions, nitrite ions, and sulfate ions contained in the water to be treated are adsorbed.

  Both the cation exchange resin and the anion exchange resin can be appropriately selected from those known in the water treatment field. The ion exchange resin includes a gel type, a porous type, and an MR type, and any type of ion exchange resin may be used as the cation exchange resin or the anion exchange resin. The cation exchange resin may be either strongly acidic or weakly acidic, or a combination thereof. The anion exchange resin may be either strongly basic or weakly basic, or a combination thereof.

[Recycled waste liquid mixing process]
In this step, a recycled waste liquid obtained by regenerating the cation exchange resin and a recycled waste liquid obtained by regenerating the anion exchange resin are mixed to obtain a mixed recycled waste liquid.

  The regeneration of the cation exchange resin can be performed by a known method using an acidic solution (acid aqueous solution). As the regenerant, for example, hydrochloric acid can be used. The recycling waste liquid obtained by the regeneration operation is acidic.

  The regeneration of the anion exchange resin can also be performed by a known method using an alkaline liquid (alkaline aqueous solution). As the regenerant, for example, an aqueous sodium hydroxide solution can be used. The reclaimed waste liquid obtained by the regenerating operation is alkaline.

  Cation exchange resin regeneration waste liquid and anion exchange resin regeneration waste liquid are mixed. By this operation, the cation exchange resin regeneration waste liquid (acidic) is at least partially neutralized by the anion exchange resin regeneration waste liquid (alkaline). Thereby, the amount of alkali added at the time of stripping can be reduced or zero.

[Stripping process]
In this step, ammonia is removed from the mixed regeneration waste liquid by stripping the mixed regeneration waste liquid under alkaline conditions.

  When the mixed recycled waste liquid obtained in the recycled waste liquid mixing step is alkaline, the mixed recycled waste liquid can be supplied to the stripping tower without adjusting the pH. Alternatively, the pH of the mixed and regenerated waste liquid can be adjusted (typically, the pH is increased) in order to make the mixed and regenerated waste liquid alkaline, or in order to further increase the pH even if the mixed and regenerated waste liquid is alkaline. . The mixed and regenerated waste liquid adjusted in pH can be supplied to the stripping tower. In order to adjust the pH, an alkali, typically sodium hydroxide, can be added to the mixed regeneration waste liquid.

  The pH of the stripping tower inlet liquid (mixed and regenerated waste liquid whose pH is adjusted as necessary) is preferably 9 to 13 from the viewpoint of converting ammonium ions to ammonia and facilitating stripping.

  The water temperature of the diffusion tower inlet liquid is preferably 40 ° C. or higher and 100 ° C. or lower from the viewpoint of facilitating volatilization of ammonia gas. For this purpose, the mixed and regenerated waste liquid supplied to the diffusion tower can be appropriately heated by a heat exchanger, a heater, or the like.

  The ammonia concentration in the stripping tower inlet liquid is preferably 300 mg / L or more from the viewpoint of suppressing energy required for evaporation. There is no special upper limit for the ammonia concentration in the stripper tower inlet liquid. However, when the concentration is high, the amount of drainage is often small, and therefore, methods such as off-site disposal may be advantageous in terms of cost. Therefore, the present invention is particularly suitable when the ammonia concentration in the stripper tower inlet liquid is 10,000 mg / L or less.

  The ammonia concentration of the treated water (water from which ammonia has been removed) obtained from the stripping tower is used to reduce the nitrogen load from the viewpoint of environmental load, such as to achieve the discharge standard, or when there is a treatment in the subsequent stage. 0 mg / L or more and 100 mg / L or less is preferable.

  As the structure of the stripping tower, a known structure can be appropriately employed in ammonia stripping, and a plate tower, a packed tower, or the like can be used as the stripping tower.

  Steam or air can be blown into the stripping tower during stripping. Alternatively, steam may be generated by providing a heater (reboiler) at the bottom of the stripping tower without blowing stripping gas.

  A gas containing ammonia gas is obtained from the stripping tower. This gas may contain water vapor, nitrogen, oxygen, etc. depending on the type of stripping gas.

[Further processing]
Ammonia gas contained in a gas (a gas containing ammonia gas) obtained from the stripping tower can be converted into nitrogen gas using an ammonia decomposition catalyst. For this purpose, it is possible to use a catalytic reactor (ammonia catalytic cracking apparatus) in which the gas obtained from the stripping tower is brought into contact with the ammonia cracking catalyst. As the structure of this catalytic reactor, a known structure in the field of ammonia decomposition can be adopted as appropriate, and a fixed bed, a fluidized bed or the like can be used.

  As the ammonia decomposition catalyst, a catalyst known in the field of ammonia decomposition can be used, and in particular, an oxidation catalyst can be used. For example, catalytically active components such as salts or oxides such as ruthenium, rhodium, palladium, iridium, platinum, titanium, iron, nickel, cobalt, vanadium, cerium, and manganese on a carrier such as titania, silica, alumina, zirconia, and zeolite Can be used. The shape of the catalyst is not particularly limited, such as a honeycomb, a wire mesh type, or a granular shape.

[Other processes]
By performing sand filtration or activated carbon treatment as a pretreatment of the treatment with the ion exchange resin, blockage or contamination of the ion exchange resin can be prevented.

[Water treatment equipment]
The water treatment apparatus according to the present invention is
An ion exchange resin tower comprising a cation exchange resin and an anion exchange resin,
A mixing device connected to the cation exchange resin regeneration waste liquid outlet and the anion exchange resin regeneration waste liquid outlet of the ion exchange resin tower; and
A stripping tower connected to the outlet of the mixing device.

-Ion exchange resin tower An ion exchange resin tower contains a cation exchange resin and an anion exchange resin. The ion exchange resin tower can include a cation exchange resin tower containing a cation exchange resin and an anion exchange resin tower containing an anion exchange resin. In this case, the cation exchange resin tower and the anion exchange resin tower are provided separately, and therefore two or more ion exchange resin towers are used. Alternatively, the ion exchange resin tower can include a mix bed of cation exchange resin and anion exchange resin. In this case, one or more ion exchange resin towers including a mix bed are used.

  As the structure of the ion exchange resin tower (cation exchange resin tower, anion exchange resin tower, or ion exchange resin tower provided with a mix bed) itself, a structure known in the field of water treatment can be appropriately employed. It is also known that the ion exchange resin tower has a regeneration liquid inlet for regenerating the ion exchange resin and a regeneration waste liquid outlet after being used for regeneration.

Mixing device The mixing device is connected to the cation exchange resin regeneration waste liquid outlet and the anion exchange resin regeneration waste liquid outlet of the ion exchange resin tower. In the mixing device, the cation exchange resin regeneration waste liquid outlet and the anion exchange resin regeneration waste liquid are mixed.

  When the cation exchange resin tower and the anion exchange resin tower are provided separately, the cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower is connected to the mixing device, and the anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower is Connected to mixing device.

  Similarly, in the case of an apparatus equipped with a mix bed, the acid regeneration waste liquid and the alkali regeneration waste liquid that are sequentially discharged are mixed by a mixing apparatus.

  The mixing device may be a tank or a simple pipe. For example, a tank (or pipe) as a mixing device is provided, a line connecting the tank (or pipe) and the cation exchange resin regeneration waste liquid outlet is provided, and the tank (or pipe) and the anion exchange resin regeneration waste liquid outlet are connected. A connecting line can be provided. In this tank (or piping), the cation exchange resin regeneration waste liquid outlet and the anion exchange resin regeneration waste liquid can be mixed.

-Stripping tower The outlet of the mixing device (the outlet for taking out the mixed recycling waste liquid) is connected to the stripping tower, and in particular, connected to the liquid inlet of the stripping tower, allowing stripping of the mixed recycling waste liquid. In the line connecting the outlet of the mixing device and the stripping tower, other devices such as a pH adjusting tank and a heat exchanger can be appropriately provided.

  Each line can be configured using piping, valves, pumps, and the like as appropriate.

[Example of water treatment equipment]
FIG. 1 shows a process flow of an example of a water treatment apparatus according to the present invention. In this apparatus, the ion exchange resin tower includes a cation exchange resin tower 4 and an anion exchange resin tower 5. Moreover, the line L16 is used as a mixing device (recycled waste liquid mixing device).

First, an operation for removing ammonium ions from the water to be treated using an ion exchange resin will be described. The water to be treated stored in the drain tank 1 is sent to the sand filter 2 via the line L1, and then sent to the activated carbon tower 3 via the line L2. Impurities such as suspended substances are removed from the water to be treated with a sand filter and an activated carbon tower. The pretreated water thus pretreated is sent to the cation exchange resin tower 4 including the cation exchange resin via the line L3. Here, the cation exchange resin adsorbs ammonium ions (NH ₄ ⁺ ). The liquid treated with the cation exchange resin is sent to the anion exchange resin tower 5 via the line L4. Here, anions (Cl ⁻ , NO ₃ ⁻ , NO ₂ ⁻ , SO ₄ ²⁻ ) contained in the water to be treated are adsorbed on the anion exchange resin. Thus, the liquid treated with the cation exchange resin and the anion exchange resin is treated water with high purity with reduced ammonium concentration, discharged from the line L5 to the outside of the water treatment apparatus, and reused as recovered water as appropriate. Or it is released to the outside world.

  In order to treat the water to be treated with both the cation exchange resin and the anion exchange resin, the cation exchange resin tower 4 and the anion exchange resin tower 5 can be arranged in series with respect to the flow of the water to be treated. In FIG. 1, an anion exchange resin tower is provided downstream of the cation exchange resin tower, but a cation exchange resin tower may be provided downstream of the anion exchange resin tower. When using a mixed bed of a cation exchange resin and an anion exchange resin, it is possible to use only one ion exchange resin tower provided with a mix bed instead of a combination of a cation exchange resin tower and an anion exchange resin tower.

  Next, operations for regenerating the ion exchange resin will be described. Regeneration water (pure water) is supplied from the regeneration water tank 11 to the cation exchange resin tower 4 and the anion exchange resin tower 5 through the lines L12 and L13, respectively, after passing through the line L11. At this time, hydrochloric acid is added from the line L31 to the regeneration water for the cation exchange resin, and sodium hydroxide is added from the line L32 to the regeneration water for the anion exchange resin. Alternatively, hydrochloric acid and sodium hydroxide may each have a storage tank and a supply line. Regenerated waste liquids from the cation exchange resin tower and the anion exchange resin tower are joined to the line L16 via the line L14 and the line L15, respectively, and are mixed with each other. The mixed recycled waste liquid is sent from the line L16 to the recycled waste liquid tank 12. Alternatively, the line L14 and the line L15 may be connected to the regeneration waste liquid tank 12, respectively. The mixed regeneration waste liquid is sent from the regeneration waste liquid tank to the pH adjustment tank 13 via the line L17. Here, sodium hydroxide is added to the mixed regeneration waste liquid from line L33. At this stage, the mixed recycling waste liquid is alkaline. This mixed and regenerated waste liquid is supplied to the heat exchanger 14 via the line L18 and heated there. The heated alkaline mixed regeneration waste liquid is supplied to the stripping tower 15 via the line 19 and is stripped by steam supplied from the line L34. Gas from the stripping tower (including ammonia gas removed from the mixed regeneration waste liquid and steam) is discharged from the stripping tower to the line L20, and diluted and adjusted to an appropriate concentration by the air supplied from the line L35. Then, it is sent to the ammonia catalytic cracking device 16. In the ammonia catalytic decomposition apparatus, ammonia is oxidized and discharged as nitrogen gas (and moisture) from the line L22 to the outside. The liquid obtained from the stripping tower is supplied to the heat exchanger 14 via the line L23 and cooled here. The cooled liquid obtained in the line L24 is high-purity water (treated water) from which ammonia has been removed, and is appropriately reused or discharged to the outside.

  According to the present invention, the amount of mixed and regenerated waste liquid can be reduced to 1/10 to 1/50 with respect to the amount of water to be treated. Therefore, compared with the case where the water to be treated is directly stripped, the heat energy required for stripping is also reduced to 1/10 to 1/50, which saves energy and reduces the processing cost. Moreover, water treatment can be performed with a smaller facility.

[Modification of existing water treatment equipment]
In order to remove ammonia from the water to be treated in which ammonia is dissolved, a water treatment apparatus including a cation exchange resin tower containing a cation exchange resin may already exist. In this case, it is possible to obtain the above-described excellent water treatment apparatus by modifying an existing water treatment apparatus.

<First modified form: existing water treatment apparatus includes a cation resin tower, but does not include an anion exchange resin and does not include a diffusion tower>
in this case,
An anion exchange resin tower comprising an anion exchange resin, arranged in series with the cation resin tower with respect to the water to be treated;
A mixing device connected to the cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower and the anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower; and
A diffusion tower connected to the outlet of the mixing device can be additionally provided in the existing water treatment device.

  For example, an existing water treatment device can have the process flow shown in FIG. In FIG. 2 (also in FIG. 3), the same symbols are assigned to the same devices and lines as in FIG. Treated water from which ammonia has been removed by the cation exchange resin tower 4 is obtained in the line L4. At the time of regeneration of the cation exchange resin, hydrochloric acid (line L31) is added to the regeneration water (line L11) from the regeneration water tank 11, and is supplied to the cation exchange resin tower 4 via the line L12. The regeneration waste liquid (line L14) from the regeneration waste liquid outlet of the cation exchange resin tower 4 can be appropriately discarded or sent to another ammonia treatment apparatus such as biological treatment.

  By providing the existing water treatment apparatus with equipment and lines shown in FIG. 1 but not shown in FIG. 2, a water treatment apparatus having the process flow shown in FIG. 1 can be obtained. The main equipment to be added is an anion exchange resin tower 5, a mixing device (line L16), and a stripping tower 15.

  The anion exchange resin tower 5 contains an anion exchange resin. This anion exchange resin tower is arranged in series with the cation resin tower with respect to the flow of water to be treated. For example, as shown in FIG. 1, the water to be treated may be treated in the cation exchange resin tower 4 and then in the anion exchange resin tower 5. Alternatively, the water to be treated may be treated with an anion exchange resin tower and then treated with a cation exchange resin tower.

  The line L16 functioning as a mixing device is connected to the cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower 4 and the anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower 5 via lines L14 and L15, respectively.

  The stripping tower 15 is connected to the outlet of the mixing device (line L16) via a regeneration waste liquid tank 12, a line L17, a pH adjustment tank 13, a line L18, a heat exchanger 14, and a line L19.

Therefore, this invention provides the kit for remodeling the water treatment apparatus containing the cation exchange resin tower | column containing a cation exchange resin. This water treatment device modification kit is
An anion exchange resin tower comprising an anion exchange resin, arranged in series with the cation resin tower with respect to the water to be treated;
A mixing device connected to the cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower and the anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower; and
A stripping tower connected to the outlet of the mixing device.

<Second modified form: When existing water treatment apparatus includes not only a cation exchange resin tower but also a diffusion tower, but does not include an anion exchange resin>
In addition to the cation exchange resin tower, the existing water treatment apparatus may include a diffusion tower connected to the cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower. In that case,
An anion exchange resin tower comprising an anion exchange resin, arranged in series with the cation resin tower with respect to the water to be treated; and
A cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower and an anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower, wherein the outlet of the mixing apparatus is connected to the diffusion tower. A mixing device can be provided in addition to the existing water treatment device. As a result, the cation resin regeneration waste liquid outlet and the diffusion tower are connected via the mixing device.

  For example, an existing water treatment apparatus can have the process flow shown in FIG. Treated water from which ammonia has been removed by the cation exchange resin tower 4 is obtained in the line L4. At the time of regeneration of the cation exchange resin, hydrochloric acid (line L31) is added to the regeneration water (line L11) from the regeneration water tank 11, and is supplied to the cation exchange resin tower 4 via the line L12. The regeneration waste liquid (line L14) from the regeneration waste liquid outlet of the cation exchange resin tower 4 is sent to the regeneration waste liquid tank 12. In the apparatus shown in FIG. 1, the mixed and regenerated waste liquid is supplied from the regenerated waste liquid tank 12 to the line L <b> 17 and used for the subsequent processing (including stripping). On the other hand, in the apparatus shown in FIG. 3, not the mixed regenerated waste liquid but the regenerated waste liquid from the cation exchange resin tower is supplied to the line L17 and subjected to the same processing as in the apparatus of FIG.

  By providing the existing water treatment apparatus with equipment and lines shown in FIG. 1 but not shown in FIG. 3, a water treatment apparatus having the process flow shown in FIG. 1 can be obtained. In the existing water treatment apparatus shown in FIG. 3, the cation resin regeneration waste liquid outlet of the cation exchange resin tower 4 and the stripping tower 15 are a regeneration waste liquid tank 12, a line L17, a pH adjustment tank 13, a line L18, a heat exchanger 14 and a line. It is connected via L19. On the other hand, in the water treatment apparatus shown in FIG. 1, the cation resin regeneration waste liquid outlet and the diffusion tower are connected via a mixing device (line 16) in addition to these devices and lines.

  The main equipment to be added is an anion exchange resin tower 5 and a mixing device (line L16).

  The anion exchange resin tower 5 contains an anion exchange resin. This anion exchange resin tower is arranged in series with the cation resin tower with respect to the flow of water to be treated. For example, as shown in FIG. 1, the water to be treated may be treated in the cation exchange resin tower 4 and then in the anion exchange resin tower 5. Alternatively, the water to be treated may be treated with an anion exchange resin tower and then treated with a cation exchange resin tower.

  The line L16 functioning as a mixing device is connected to the cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower 4 and the anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower 5 via lines L14 and L15, respectively. And the stripping tower 15 is connected to the exit of a mixing apparatus (line L16) via the regeneration waste liquid tank 12, the line L17, the pH adjustment tank 13, the line L18, the heat exchanger 14, and the line L19.

Accordingly, the present invention provides a kit for remodeling a water treatment apparatus comprising a cation exchange resin tower containing a cation exchange resin and a diffusion tower connected to a cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower. . This water treatment device modification kit is
An anion exchange resin tower comprising an anion exchange resin, arranged in series with the cation resin tower with respect to the water to be treated; and
A cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower and an anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower, wherein the outlet of the mixing apparatus is connected to the diffusion tower. Includes mixing device.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited by this.

[Example 1]
A process simulation was performed assuming an apparatus having the process flow shown in FIG.

  The amount and concentration of water in each process are summarized in Table 1.

In addition, the following were assumed as treated water.
Water to be treated: NH ₄ Cl, water adjusted to contain 127 mg / L of Cl ions in addition to 50 mg / L of ammonia (ammonium ions) as NH ₄ —N (nitrogen equivalent concentration).
-Regeneration HCl (L31): Industrial 35 mass% HCl aqueous solution.
-Regeneration NaOH (L32) and stripping NaOH (L33): Industrial 25 wt% NaOH aqueous solution.
-Reclaimed water (L11): pure water.
-Steam for heating (L34): 0.5 MPa saturated steam.

The anion tower regeneration waste liquid (L15) contained 7.1 kmol / day NaOH. At this time, the amount of NaOH (L33) required for adjusting the pH of the solution obtained by mixing the anion tower regeneration waste liquid with the anion tower regeneration waste liquid (L17, 50 m ³ / day) is 2 kg / day (in terms of 100 mass% NaOH) / Met.

[Comparative Example 1]
The cation tower regeneration waste liquid (L14) was not mixed with the anion tower regeneration waste liquid (L15), and the cation tower regeneration waste liquid was sent to the pH adjustment tank 13 as it was. At this time, NaOH was added from the line L33 so that the pH of the stripper tower inlet liquid (L19) was the same as in Example 1 (pH = 11).

A process simulation was performed in the same manner as in Example 1 except for the above. The amount of NaOH necessary for neutralizing the liquid flowing through the line L17 (25 m ³ / day) was 287 kg / day (in terms of 100% by mass NaOH).

DESCRIPTION OF SYMBOLS 1 Wastewater (treated water) tank 2 Sand filter 3 Activated carbon tower 4 Cation exchange resin tower 5 Anion exchange resin tower 11 Regeneration water tank 12 Recycled waste liquid tank 13 pH adjustment tank 14 Heat exchanger 15 Ammonia diffusion tower 16 Ammonia catalytic decomposition apparatus

Claims (7)

An ion exchange step of passing water to be treated in which ammonia is dissolved through a cation exchange resin and an anion exchange resin;
A regeneration waste liquid mixing step of mixing a regeneration waste liquid obtained by regenerating the cation exchange resin and a regeneration waste liquid obtained by regenerating the anion exchange resin; and
A water treatment method including a stripping step of removing ammonia from a mixed regenerated waste liquid by stripping the mixed regenerated waste liquid under alkaline conditions.   The method according to claim 1, wherein the ammonia concentration in the water to be treated is 10 mg / L or more and 200 mg / L or less in terms of nitrogen. An ion exchange resin tower comprising a cation exchange resin and an anion exchange resin,
A mixing device connected to the cation exchange resin regeneration waste liquid outlet and the anion exchange resin regeneration waste liquid outlet of the ion exchange resin tower; and
A water treatment device comprising a stripping tower connected to the outlet of the mixing device. A method for remodeling a water treatment apparatus including a cation exchange resin tower containing a cation exchange resin,
An anion exchange resin tower comprising an anion exchange resin, arranged in series with the cation resin tower with respect to the water to be treated;
A mixing device connected to the cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower and the anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower; and
A method for remodeling a water treatment apparatus, comprising providing a diffusion tower connected to an outlet of the mixing apparatus. A kit for remodeling a water treatment apparatus including a cation exchange resin tower including a cation exchange resin,
An anion exchange resin tower comprising an anion exchange resin, arranged in series with the cation resin tower with respect to the water to be treated;
A mixing device connected to the cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower and the anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower; and
A kit for remodeling a water treatment apparatus, comprising a diffusion tower connected to an outlet of the mixing apparatus. A method for remodeling a water treatment apparatus comprising: a cation exchange resin tower containing a cation exchange resin; and a diffusion tower connected to a cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower,
An anion exchange resin tower comprising an anion exchange resin, arranged in series with the cation resin tower with respect to the water to be treated; and
A cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower and an anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower, wherein the outlet of the mixing apparatus is connected to the diffusion tower. A method of remodeling a water treatment device comprising providing a mixing device. A kit for remodeling a water treatment apparatus comprising a cation exchange resin tower containing a cation exchange resin, and a diffusion tower connected to a cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower,
An anion exchange resin tower comprising an anion exchange resin, arranged in series with the cation resin tower with respect to the water to be treated; and
A cation exchange resin regeneration waste liquid outlet of the cation exchange resin tower and an anion exchange resin regeneration waste liquid outlet of the anion exchange resin tower, wherein the outlet of the mixing apparatus is connected to the diffusion tower. Water treatment device modification kit including mixing device.

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