JP2012196630A - Treatment equipment and treatment method of acid liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently and economically treat a non-ionic/cationic water-soluble compound such as a monoethanolamine-containing dilute hydrochloric acid wastewater that is discharged during regeneration of condensate desalination devices used in nuclear power plants and thermal power plants.SOLUTION: A non-ionic/cationic water-soluble compound is passed through a raw water chamber 22 of a neutralization dialysis device 2 that is partitioned into the raw water chamber 22 and an alkali solution chamber 23 by an anion-exchange membrane 21, and an alkali solution is passed through the alkali solution chamber 23 to neutralize and desalinize the acid liquid. An alkali wastewater produced by neutralization and desalinization treatment is subject to catalytic oxidation treatment in a catalytic oxidation device 10.

Description

  The present invention relates to a processing apparatus and method for efficiently neutralizing and desalting or reducing the volume of an acidic liquid containing a nonionic or cationic water-soluble compound. Specifically, an acidic liquid containing a nonionic or cationic water-soluble compound such as a monoethanolamine-containing dilute hydrochloric acid liquid discharged during the regeneration of a condensate demineralizer of a nuclear power plant or a thermal power plant can be efficiently and The present invention relates to a processing apparatus and a processing method for economically neutralizing desalting or neutralizing desalting.

  In the condensate process of nuclear power generation and thermal power generation, amines such as monoethanolamine (MEA) are used as anticorrosives for steam generation lines. Usually, these amines are captured by the cation exchange resin of a condensate demineralizer (hereinafter sometimes referred to as “condemi”) provided in the line and regenerated when the condensate demineralizer is regenerated. It is contained in the waste liquid and discharged. The discharged amines become COD sources and eutrophication sources and contaminate rivers and lakes, so it is necessary to treat them.

  Since this condemi regeneration waste liquid is a liquid with high COD and nitrogen load, it is generally treated by thermal decomposition or submerged combustion. However, in order to use the condemi regeneration waste liquid as it is for thermal decomposition or submerged combustion apparatus, Since the amount is large and the processing cost is high, the volume reduction is desired.

The present applicant has previously proposed the following (1) and (2) as a technique for efficiently and economically treating an acidic liquid such as a waste condensate regeneration liquid.
(1) An acidic liquid containing a nitrogen compound is passed through the one chamber separated by the anion exchange membrane into one chamber and the other chamber, and an alkaline solution is passed through the other chamber. A method and an apparatus for neutralizing and desalting the acidic liquid and concentrating the nitrogen compound in the obtained neutralized and desalted liquid (Patent Document 1).
(2) A nonionic or cationic water-soluble compound is allowed to flow through the acidic liquid into the one chamber separated by the anion exchange membrane into one chamber and the other chamber, and into the other chamber. A method and apparatus for neutralizing desalting and reducing the volume of an acidic solution by passing an alkaline solution having an osmotic pressure higher than that of the acidic solution (Patent Document 2).

  If it is processing technology of patent documents 1 and 2, it can treat acid liquids, such as waste liquid of waste condensies economically and efficiently, but in neutralization desalination processing or neutralization desalination volume reduction of acid liquid Since 3-30% of organic substances such as ethanolamine and nitrogen components pass through the anion exchange membrane and move to the alkaline solution side from the acidic solution, the alkali after neutralization desalting or neutralization desalting volume reduction treatment The solution (hereinafter, the used alkaline solution may be referred to as “alkaline waste liquid”) requires treatment of COD and N (nitrogen) components.

  Conventionally, COD and N treatment techniques include biological treatment techniques, submerged combustion techniques, accelerated oxidation techniques using ultraviolet rays, ozone, and persulfuric acid, and catalytic oxidation techniques.

In biological treatment, COD and N components can be removed by organic matter decomposition and nitrification denitrification, but there are the following problems. That is, in the biological treatment, it is necessary to adjust the pH in the system to a neutral region, while the alkaline waste liquid becomes alkaline after the neutralization and desalting treatment in order to keep the deoxidation rate high. Prior to this, it is necessary to add an acid to the alkaline waste liquid to neutralize it. In addition, since N treatment by living organisms has an optimum pH, strict pH adjustment is essential, but when biodegradation decomposes and nitrifies alkali amines and N components in the following reaction, the pH decreases. Therefore, in order to maintain neutrality, it is necessary to add an alkali this time. Then, when denitrification occurs, the pH rises, so it is necessary to add an acid in order to maintain neutrality.
NH ₄ ⁺ + 2O ₂ → NO ₃ ⁻ + 2H ⁺ + H ₂ O (Because an acid is generated, it is necessary to neutralize with an alkali)
^{_{6NO 3 - + 5CH 3 OH →}} 3N 2 + 5CO 2 + 6OH - + 7H 2 O ( alkali must be neutralized with an acid to generate)

In addition, the biological treatment facility is composed of a tank such as an organic matter decomposition tank, a nitrification tank, a denitrification tank, a re-aeration tank, and a sedimentation tank, and requires a lot of labor for maintenance in order to stably maintain the respective facilities and organisms.
In general, the upper limit of the salt concentration that can be biologically treated is about 3% by weight, which is the salt concentration of seawater. Therefore, in order to adjust the salt concentration of the alkaline waste liquid to several percent or less so that biological treatment is possible, dilution is performed. It is necessary to dilute with water. That is, when the alkaline waste liquid is an alkaline solution of about 0.5 N or more, the salt concentration becomes 3% by weight (the generated salt is NaCl) or more as calculated by the following formula, so that dilution is necessary. When the alkaline waste liquid is diluted, the amount of water to be treated increases, and it is necessary to increase the size of all treatment facilities.
0.5N × 58.5 = about 30g / L

  On the other hand, the submerged combustion technology is suitable for high-concentration waste liquid treatment at a percent level. However, COD and TN in the alkaline waste liquid have a concentration of about several tens to 1,000 mg / L, so that moisture is combusted. Therefore, the fuel cost is excessive and inefficient.

  Ultraviolet oxidation and accelerated oxidation technology using ozone and persulfuric acid are expensive generators for ultraviolet rays and ozone, which are oxidants, and nitrogen components are oxidized to nitric acid. Is inefficient because it is required separately.

  On the other hand, catalytic oxidation is excellent in that there is no problem as described above, but it is necessary to consider the applicability of the water to be treated to catalytic oxidation.

Japanese Patent Application No. 2010-262511 Japanese Patent Application No. 2010-262506

  The present invention provides an acidic liquid treatment apparatus and treatment method for industrially advantageously treating the alkaline waste liquid generated in the neutralization desalination or neutralization desalination volume reduction treatment described in Patent Documents 1 and 2. This is the issue.

As a result of various investigations on the treatment technology of alcal waste liquid generated in the above neutralization desalting or neutralization desalting and volume reduction treatment, the present inventors have found that this alkaline waste liquid can be subjected to catalytic oxidation treatment with other COD, It was found that this is the simplest method for obtaining water quality that can be discharged compared to N treatment technology.
The present invention has been achieved on the basis of such findings, and the gist thereof is as follows.

[1] An apparatus for treating an acidic liquid containing a nonionic or cationic water-soluble compound, wherein the acidic liquid is introduced into the one chamber separated by the anion exchange membrane into one chamber and the other chamber. The neutralization and desalination apparatus that neutralizes and desalinates the acidic solution by passing an alkaline solution through the other chamber while passing water, and used for neutralization and desalting in the neutralization and desalination apparatus An acidic liquid treatment apparatus comprising: a catalytic oxidation apparatus for catalytic oxidation of an alkaline liquid.

[2] The apparatus according to [1], further comprising a concentrating device for concentrating the neutralized and desalted treatment solution neutralized and desalted by the neutralizing and desalting device, wherein the diluted liquid generated in the concentrating device A processing apparatus for an acidic liquid, wherein the apparatus is subjected to catalytic oxidation by a catalytic oxidation apparatus together with an alkaline liquid used for desalting.

[3] The acidic liquid treatment apparatus according to [2], wherein the concentration apparatus is any one of a distillation concentration apparatus, an electrodeionization apparatus, and an electrodialysis apparatus.

[4] An apparatus for treating an acidic liquid containing a nonionic or cationic water-soluble compound, wherein the acidic liquid is introduced into the one chamber separated by the anion exchange membrane into one chamber and the other chamber. A neutralization and desalting and volume reducing device for passing water and passing an alkaline solution having a higher osmotic pressure than the acidic solution into the other chamber to neutralize and desalt and reduce the volume of the acidic solution; An apparatus for treating an acidic liquid, comprising: a catalytic oxidation apparatus that catalytically oxidizes an alkaline liquid used for neutralization and desalting and volume reduction in the neutralization and desalting and volume reducing apparatus.

[5] A method for treating an acidic liquid containing a nonionic or cationic water-soluble compound, wherein the acidic liquid is introduced into the one chamber separated from the one chamber by the anion exchange membrane. The neutralization and desalting step of neutralizing and desalting the acidic solution by passing an alkaline solution through the other chamber while passing water, and used for neutralization and desalting in the neutralization and desalting step A method for treating an acidic liquid, comprising a catalytic oxidation step of catalytically oxidizing an alkaline liquid.

[6] In [5], the method includes a concentration step of concentrating the neutralized and desalted solution neutralized and desalted in the neutralization and desalting step, and the dilute solution generated in the concentration step is neutralized and dehydrated. A method for treating an acidic liquid, characterized by catalytic oxidation in a catalytic oxidation step together with an alkaline liquid used for desalting.

[7] The method for treating an acidic liquid according to [6], wherein the concentration step is a step using any one of a distillation concentration device, an electrodeionization device, and an electrodialysis device.

[8] A method for treating an acidic liquid containing a nonionic or cationic water-soluble compound, wherein the acidic liquid is applied to the one chamber separated from the other chamber by an anion exchange membrane. A neutralization and desalting and volume reducing step of passing an alkaline solution having an osmotic pressure higher than that of the acidic solution into the other chamber to neutralize and desalinate and reduce the volume of the acidic solution; And a catalytic oxidation step of catalytically oxidizing the alkaline solution used for neutralization desalting and volume reduction in the neutralization desalting and volume reduction step.

  According to the present invention, an acidic liquid containing a nonionic or cationic water-soluble compound (hereinafter referred to as a “nonionic / cationic water-soluble compound” is referred to as “nonionic / cationic water-soluble compound”). The acidic liquid contained may be referred to as “non-ionic / cationic water-soluble compound-containing acidic liquid” or “raw water”). By oxidizing, it can be processed easily and efficiently into water quality that can be discharged with a simple device.

  That is, the present inventor has found that in the catalytic oxidation treatment, it is most efficient that the pH of the water to be treated is alkaline of about 10 to 12. Alkaline waste liquid generated by neutralization desalting or neutralization desalting and volume reduction treatment of nonionic / cationic water-soluble compound-containing acidic liquid usually has a pH of about 10 to 14, so that a slight pH adjustment is performed as necessary. It can be applied to catalytic oxidation only, and no dilution water is required. Moreover, if it is catalytic oxidation treatment, nitrogen components such as amine and ammonia in the alkaline waste liquid can be efficiently decomposed, and good water quality with COD <10 mg / L and TN <20 to 60 mg / L. Treated water can be obtained. This is water quality that sufficiently satisfies the drainage standards of the sea area. In addition, since the pH is lowered due to decomposition of amine, ammonia, etc., the amount of acid necessary for neutralization is greatly reduced even in pH adjustment during discharge.

It is a systematic diagram which shows embodiment of the processing apparatus and method of the acidic liquid of this invention. It is a systematic diagram which shows other embodiment of the processing apparatus and method of the acidic liquid of this invention. It is typical sectional drawing which shows schematic structure of an example of an electrodeionization apparatus suitable as a concentration apparatus which concerns on this invention. It is typical sectional drawing which shows schematic structure of the other example of the electrodeionization apparatus suitable as a concentration apparatus which concerns on this invention. 1 is a system diagram showing a configuration of a neutralization dialysis apparatus employed in Example 1. FIG.

  Embodiments of an acidic liquid treatment apparatus and treatment method of the present invention will be described below in detail with reference to the drawings.

In this specification, the nonionic / cationic water-soluble compound-containing acidic liquid to be treated in the present invention contains hydrochloric acid (HCl) as an acid, and such acidic liquid is used as an alkaline solution by using a sodium hydroxide aqueous solution. The present invention will be described by exemplifying the case of neutralization desalting and volume reduction treatment. However, the acid contained in the acidic liquid to be treated in the present invention is not limited to hydrochloric acid, but other acids such as sulfuric acid. There may be. When the acid contained in the nonionic / cationic water-soluble compound-containing acidic solution is another acid such as sulfuric acid, in the following description, the Cl ⁻ ion is an anion that forms a H ⁺ pair of an acid such as SO ₄ ^2- ion. In addition, when an alkaline solution other than an aqueous sodium hydroxide solution is used as the alkaline solution, in the following description, Na ⁺ ions are cations that form a pair of alkali OH ⁻ such as K ⁺ ions.

1 and 2 are system diagrams showing an embodiment of the present invention. The apparatus shown in FIG. 1 is a process liquid circulation of an electrodeionization apparatus 4 that also serves as a raw water tank 1, a neutralization dialysis apparatus 2, and a relay tank. The tank 3, the electrodeionization apparatus 4, the treated water tank 5, and the catalytic oxidation apparatus 10 are mainly configured.
2 mainly includes a raw water tank 1, a neutralization dialysis apparatus 2, a distillation concentration apparatus 6, a submerged combustion apparatus 7, and a catalytic oxidation apparatus 10.

[Nonionic / cationic water-soluble compound-containing acidic solution]
Although there is no restriction | limiting in particular as a nonionic / cationic water-soluble compound containing acidic liquid used as the process target of this invention, For example, the following (1)-(3) is mentioned.
(1) Nitrogen compound-containing acidic liquid (2) Metal ion-containing acidic liquid (3) Surfactant, detergent-containing acidic liquid

  (1) As a nitrogen compound-containing acidic liquid, for example, in a thermal power plant or a pressurized water nuclear power plant, a condensate demineralizer (condemi) containing an organic amine such as monoethanolamine (MEA) or morpholine as an anticorrosive agent is used. And an acidic waste liquid regenerated from the cation exchange resin used in the above (hereinafter sometimes referred to as “condemi-regenerated acidic waste liquid”).

  Since acids such as hydrochloric acid and sulfuric acid are used to regenerate the cation exchange resin, the dehydrated acid waste solution contains organic amines that have been desorbed (accurately, acid salts of organic amines) and regenerated chemicals such as hydrochloric acid and sulfuric acid. In addition to acid, it contains trace amounts of copper ions, iron ions, and ammonia, which is a decomposition product of organic amines.

  The concentration and pH of the organic amine and other water quality components in such a condensate regeneration acidic waste liquid vary depending on the type of the waste liquid, but have the following water quality, for example.

  (2) Examples of the metal ion-containing acidic liquid include a metal-dissolved acid drainage discharged from a pickling process using a volatile acid in an iron factory, a metal material processing factory, or the like.

(3) Examples of the surfactant and the cleaning agent-containing acidic liquid include rinse waste water discharged from a semiconductor manufacturing plant.
That is, the semiconductor from the manufacturing plant, _PH2.5～3.5, in concentration of H 2 _{O 2} 10 to 30 ppm, the surfactant as TOC component, acetone, isopropanol, rinsed for 1~3ppm containing a carboxylic acid such as acetic acid Waste water is discharged. Conventionally, such semiconductor rinsing waste water is obtained by using a first activated carbon adsorption tower, a weakly basic anion exchange resin tower, a strongly acidic cation exchange resin tower, a strongly basic anion exchange resin tower, a reverse osmosis membrane treatment apparatus, and a high-pressure ultraviolet irradiation apparatus. The second activated carbon adsorption tower, the vacuum degassing tower, and the mixed bed type ion exchange resin tower are sequentially passed through the water, and in such a conventional method for treating semiconductor rinse wastewater, the pH is 2.5 to Since the acidic rinse wastewater of 3.5 is treated, the performance of the first activated carbon adsorption tower is deteriorated with time, the H ₂ O ₂ decomposition performance of the first activated carbon adsorption tower is lowered, and it flows out from the activated carbon adsorption tower. H ₂ O ₂ degrades the weak base anion resin tower resin by oxidation with H ₂ O ₂ and reduces the performance of the weak base anion exchange resin tower; H ₂ O _{2 of} the first activated carbon adsorption tower Rinse when degradation performance deteriorates However, according to the present invention, such an acidic liquid can be efficiently treated. However, according to the present invention, there is a problem that the adsorption performance of the surfactant in water is also lowered and the performance of the latter strongly basic anion exchange resin tower is lowered. can do.

[Neutralization desalination treatment]
In the neutralization desalination treatment according to the present invention, first, a nonionic / cationic water-soluble compound-containing acidic liquid as raw water is passed through one chamber separated by an anion exchange membrane into one chamber and the other chamber. While watering, the alkali solution is passed through the other chamber to neutralize and desalinate the raw water.

  A neutralization dialysis apparatus (diffusion dialysis apparatus) 2 using an anion exchange membrane is preferably used as the apparatus used for the neutralization and desalting treatment of the raw water.

FIG. 1 shows an example in which a neutralization dialysis device (diffusion dialysis device) 2 is used for the neutralization and desalting treatment of raw water. The raw water in the raw water tank 1 is separated by a pre-filter 11 by a pump P _1. After the removal, the inside is introduced into the raw water chamber 22 of the neutralization dialysis apparatus 2 which is partitioned into the raw water chamber 22 and the alkaline solution chamber 23 by the anion exchange membrane 21. Here, the pre-filter 11 is provided as necessary. On the other hand, the alkaline solution chamber 23, from the alkali solution tank 24, the alkali solution is introduced by a pump P _2.

  As this alkaline solution, an aqueous solution of a soluble alkali compound such as sodium hydroxide (NaOH), potassium hydroxide, lithium hydroxide, sodium carbonate or the like can be used.

In order to separate the mixed bed resin of the anion exchange resin and the cation exchange resin in the condemi, using a technique of separating by utilizing a specific gravity difference between the anion exchange resin and the cation exchange resin using a 16 wt% NaOH aqueous solution. In other locations, the alkaline waste liquid used for the separation is separately discharged.
As described above, an alkaline waste liquid may be excessively discharged at a condensate regeneration site. In the present invention, an alkaline waste liquid such as such a condemi regeneration alkaline waste liquid may be used as an alkaline solution.
As the alkaline solution, an alkaline waste liquid discharged from another facility may be used.

In the neutralization dialysis device 2, the Cl ⁻ ions in the raw water introduced into the raw water chamber 22 pass through the anion exchange membrane 21 and move to the alkaline solution chamber 23, and are desalted. The raw water is neutralized by OH ⁻ ions permeating the anion exchange membrane 21 and moving to the raw water chamber 22. The effluent from the raw water chamber 22 is returned to the raw water tank 1 and the raw water is circulated. On the other hand, the effluent from the alkaline solution chamber 23 is also returned to the alkaline solution storage tank 24 and circulated.

  In such neutralization and desalting treatment by the neutralization dialysis apparatus 2, it is preferable to adopt the following aspect.

(1) As the anion exchange membrane 21, a membrane excellent in acid resistance and alkali resistance is used. Further, the wetted surface of the neutralization dialysis apparatus 2 is also preferably made of a material having excellent corrosion resistance. For example, a lining made of a fluororesin such as polytetrafluoroethylene is preferable.

(2) A concentration polarization layer is formed on the surface of the anion exchange membrane, and this becomes the diffusion limiting rate of the substance, and the permeation transfer rate of Cl ⁻ ions, OH ⁻ ions and water is limited. In order to prevent this and increase the permeation transfer speed, it is preferable to increase the membrane surface flow velocity in order to reduce the concentration polarization in the vicinity of the anion exchange membrane surface, specifically, the raw water chamber 22 side and the alkaline solution chamber 23 side. It is preferable that the film surface flow velocity is 0.1 cm / sec or more, for example, 1 to 8 cm / sec. If the membrane surface flow rate is low, the movement speed of Cl ^- ions and OH ^- ions cannot be increased, and it takes a long time to obtain a desired neutralized desalting solution. However, excessively increasing the membrane surface flow velocity is not realistic in terms of the device configuration. To obtain such a film surface velocity, as the raw water pump P ₁ and the alkaline solution pump P _2, it is preferable to use a high velocity liquid feed capable diaphragm pump.

(3) As the alkaline solution, a solution having a total amount of acid consumption (mg-CaCO ₃ ) required for neutralization more than 1 times the total amount of alkali consumption of raw water (mg-CaCO ₃ ) is used.
Note that the migration rate of Cl ⁻ and OH ^{− in} the anion exchange membrane is determined by the ease of ion migration represented by the ultimate molar conductivity, and the ultimate molar conductivity of Cl ⁻ and OH ⁻ is 198.3 Scm, respectively. ² · mol ⁻¹ , 76.35 Scm ² · mol ⁻¹ . Therefore, it can be seen that OH ⁻ can easily move 2.6 times as much as Cl ⁻ . Therefore, in order to maintain a high transfer rate of Cl ⁻ from the acidic solution to the alkaline solution side, the OH ⁻ concentration of the alkaline solution should be at least 1 / 2.6 times the Cl ⁻ concentration of the acidic solution. Is desirable.
When the alkali (NaOH) concentration is increased, the osmotic pressure of the alkaline solution becomes higher than the osmotic pressure of the raw water, the water in the raw water passes through the anion exchange membrane and moves to the alkaline solution side, and the raw water is concentrated. It becomes like this.

  Accordingly, in the case where an alkaline waste solution such as the above-mentioned condemi regeneration alkaline waste solution is used as the alkaline solution, when the alkali concentration is insufficient, it is preferable to adjust the concentration by adding an alkali such as NaOH as necessary.

(4) The neutralization and desalination treatment is completed when the pH of the resulting neutralization and desalination treatment solution (the effluent from the raw water chamber 22) becomes neutral, for example, about 5 to 9, and the obtained The Japanese desalting solution is preferably subjected to the subsequent concentration treatment.
If the pH of the neutralization desalting treatment solution is less than 3, the neutralization desalting treatment is insufficient, and the effect of the present invention by performing the neutralization desalting treatment prior to the concentration treatment cannot be sufficiently obtained. . When the pH of the neutralization desalting treatment solution is excessively increased, the amount of Na ⁺ ions that pass through the anion exchange membrane 21 from the alkaline solution chamber 23 side and migrate to the raw water chamber 22 side increases (as described below, anion Even in the exchange membrane, there is a slight amount of permeation of the cation component.), The total ion amount in the subsequent concentration process is increased, which is inefficient.

  For the purpose of pH control, a flow-through pH meter is installed in the outflow pipe of the raw water chamber 22 of the neutralization dialysis apparatus 2 to monitor the pH of the effluent in the raw water chamber 22, and this pH value reaches a predetermined value. Then, you may make it switch the liquid supply of the effluent of the raw | natural water chamber 22 from the raw | natural water tank 1 to the to-be-processed liquid circulation tank 3 of the electrodeionization apparatus 4. FIG.

  The flow direction of the raw water in the raw water chamber 22 and the flow direction of the alkaline solution in the alkaline solution chamber 23 in the neutralization dialysis apparatus 2 may be cocurrent or countercurrent. In order to make the outlet water quality close to neutral by making a difference in the acid consumption of the alkaline liquid, it is preferable to use counter-flow water as shown in FIG.

In addition, the raw water and the alkaline solution can be passed through in a transient manner, but generally, neutralization dialysis cannot be performed sufficiently in a transient manner as shown in FIG. Circulating water is preferable.
When continuous treatment is performed instead of batch processing, raw water is introduced into the raw water tank 1 and the neutralized desalting treatment liquid returned from the raw water chamber 22 of the neutralization dialysis apparatus 2 is received by the raw water tank 1. It is preferable to take out a part of the liquid in the tank from the raw water tank 1 and use it for the next concentration treatment.

  In FIG. 1, the neutralization dialysis apparatus 2 has a raw water chamber 22 and an alkaline solution chamber 23 each formed by a single anion exchange membrane 21. There is no limitation, and for example, a plurality of anion exchange membranes such as an alkali solution chamber / anion exchange membrane / raw water chamber / anion exchange membrane / alkali solution chamber / alkali exchange membrane / raw water chamber / anion exchange membrane / alkaline solution chamber. Thus, a plurality of raw water chambers and alkaline solution chambers may be alternately formed.

According to the present invention, by neutralization and desalting using such a neutralization dialysis apparatus, the raw water is neutralized to neutral pH 5-9, such as pH 6-8 (about pH 7) as described above. , preferably Cl ^- ion concentration raw water Cl ^- can be obtained neutralization desalting solution was reduced to 30-50% of the ion concentration. In addition, when this neutralization desalination treatment liquid is concentrated with an electrodeionization apparatus or an electrodialysis apparatus, a cation such as a nitrogen compound in the neutralization desalination treatment liquid is required in order to secure the ion concentration of the liquid to be treated for energization. The concentration of the active compound is preferably 1000 mg / L or more, particularly about 5000 to 20000 mg / L.

[Catalytic oxidation treatment]
It is generally known that even the anion exchange membrane 21 permeates a cation component and a nonionic component, and an alkali is obtained by the neutralization desalting treatment as described above or the neutralization desalting volume reduction treatment described later. Movement of cation components (for example, Na ⁺ ions of NaOH) and nonionic components from the solution 23 side to the raw water chamber 22 is also caused by nonionic / cationic water-soluble compounds from the raw water chamber 22 side to the alkaline solution chamber 23. There is a movement of cationic and nonionic components.

Therefore, the alkaline solution (alkaline waste solution) used for neutralization desalting or neutralization desalting reduction treatment of raw water contains Cl ⁻ ions dialyzed from the raw water, and neutralizes the raw water (OH ⁻ to the raw water chamber). A weakly alkaline liquid whose pH is decreased and the liquid volume is increased by the movement of the water from the raw water and a certain amount of nonionic / cationic water solution that has permeated the anion exchange membrane 21 from the raw water chamber 22. It contains a chemical compound.
However, since the concentration of the nonionic / cationic water-soluble compound is low, in the present invention, this alkaline waste liquid is treated with a nonionic / cationic water-soluble compound such as a nitrogen compound in the catalytic oxidation apparatus 10 as shown in FIG. After decomposition, neutralize with acid and discharge.

  The COD components that are decomposed and removed by this catalytic oxidation treatment are organic acids of acidic organic substances, amines and amides of basic organic substances, and the like. The N component is an organic nitrogen component capable of catalytic oxidation such as amine and amide, hydrazine, ammonia and the like among the above-mentioned COD components.

  As the catalyst used for the catalytic oxidation treatment, a metal peroxide catalyst carrying a metal that becomes a peroxide can be suitably used. For example, there is a material in which Ni or Co is supported on granular zeolite having a cation exchange capacity by an ion exchange operation, and then these metals are converted into oxides (peroxides) by an activation treatment.

  As the catalyst oxidation apparatus 10, a catalyst packed tower having a packed bed filled with such a catalyst is used, and an alkaline waste liquid is passed through the catalyst packed tower in a downward flow or an upward flow for catalytic oxidation treatment. preferable.

As the oxidizing agent, sodium hypochlorite, or one or more of hydrogen peroxide, persulfuric acid, ozone and the like can be used if denitrification is not required. Since sodium hypochlorite causes not only organic oxidation but also the following denitrogenation reaction, COD and N can be treated.
For ammonia:
NH ₄ ⁺ +3/2 NaClO → 1 / 2N ₂ +3/2 NaCl + 3 / 2H ₂ O + H ⁺
For hydrazine:
N ₂ H ₄ + 2NaClO → N ₂ + 2NaCl + 2H ₂ O

  The addition amount of the oxidizing agent is appropriately adjusted depending on the contents of the COD component and N component in the alkaline waste liquid. In general, it is preferable to be about 1 to 2 times the theoretically required amount, particularly about 1.2 to 1.5 times.

  As the conditions for the catalytic oxidation treatment, the treatment can be performed with an alkaline pH of 10 to 13, preferably 11 to 12, and the temperature is 30 to 80 ° C, preferably 40 to 60 ° C.

Usually, since the alkaline waste liquid after neutralization desalting treatment has a pH of about 10 to 14, it can be subjected to catalytic oxidation treatment with almost no pH adjustment.
Moreover, about temperature, what is necessary is just to heat an alkaline waste liquid as needed, and to make it flow through a catalytic oxidation packed tower.

  The catalytic oxidation treatment liquid obtained by the catalytic oxidation apparatus is a liquid having a pH of about 8 to 13 in which the COD component and N component in the alkaline waste liquid are sufficiently decomposed and removed, and the pH is slightly lowered by the decomposition of amine and ammonia. Therefore, it is possible to add acid such as hydrochloric acid to adjust the pH to neutral and discharge it. However, the amount of acid added at that time is much larger than that when the alkaline waste solution is adjusted to pH and discharged. Reduced to

[Concentration treatment]
In FIG. 1, the neutralized desalting treatment solution of raw water obtained by the neutralization dialysis apparatus 2 is then subjected to a concentration treatment.

  This concentration treatment can be performed by distillation concentration, or by using an electrodeionization apparatus or an electrodialysis apparatus. In particular, an electrodeionization apparatus or an electrodialysis apparatus can be preferably used, and in particular, an electrodeionization apparatus. Is preferably used.

An electrodeionization apparatus or an electrodialysis apparatus includes an anode and a cathode, and a dilution chamber and a concentration chamber partitioned by an ion-permeable membrane between the anode and the cathode, and applies a DC voltage between the anode and the cathode. In this way, ions derived from cationic water-soluble compounds such as organic amines and NH ₄ ⁺ and ions derived from acids and alkalis such as Na ⁺ and Cl ⁻ in the neutralization desalting treatment liquid introduced into the dilution chamber The ion-permeable membrane is permeated and separated and collected in the concentration chamber.

FIG. 1 shows an example in which the electrodeionization device 4 is used for concentration, and the neutralization demineralization treatment liquid that has flowed out from the raw water chamber 22 of the neutralization dialysis device 2 is treated liquid circulation tank 3 of the electrodeionization device 4. Then, after the fine particle component is removed by the prefilter 12 by the pump P ₃ , it is introduced into the electrodeionization device 4. Here, the pre-filter 12 is provided as necessary.

  3 and 4 are schematic cross-sectional views showing a schematic configuration of an example of an electrodeionization apparatus suitably used as a concentrator in the present invention. In FIGS. 3 and 4, the members having the same functions are the same. The code | symbol is attached | subjected.

  The electrodeionization apparatus 4 in FIG. 3 includes a plurality of anion exchange membranes (A membranes) 43 and cation exchange membranes (C membranes) 44 arranged alternately between electrodes (anode 41, cathode 42), and a concentration chamber 45. The dilution chambers 46 are alternately formed.

  The dilution chamber 46 is filled with a cation exchange resin, which is a cation exchanger, or an anion exchange resin, which is an anion exchanger, and a cation exchange resin, which is a cation exchanger. In addition, as an ion exchanger, you may use not only an ion exchange resin but an ion exchange fiber or a graft exchanger. The ratio (volume ratio) between the anion exchanger and the cation exchanger filled in the dilution chamber 46 is preferably anion exchanger: cation exchanger = 95 to 0: 5 to 100. As described above, the reason why only the cation exchanger or the combination of the cation exchanger and the anion exchanger is used is that the cation exchanger is present in the cell serving as the flow path in the dilution chamber 46. This is because the removal efficiency can be improved.

  The concentration chamber 45, the anode chamber 47, and the cathode chamber 48 are also filled with a mixture of anion exchange resin and cation exchange resin as necessary. In addition to an ion exchanger such as an ion exchange resin, an electric conductor such as activated carbon or metal may be filled in the concentration chamber 45, the anode chamber 47, and the cathode chamber 48. As an electric conductor, in order to stabilize the electric resistance value in the concentration chamber, the anode chamber, and the cathode chamber, the electric resistance of the liquid to be treated or the dilution water can be lowered, and the water passage pressure of the cell is not increased. There is no particular limitation. However, materials that are susceptible to redox by directly touching the electrodes are not suitable.

  The anode chamber 47 is not filled with an anion exchange resin, and when filled, only the cation exchange resin is used. This is because anion exchange resins are susceptible to oxidative degradation.

A neutralization and desalination treatment liquid, which is a treatment liquid of the electrodeionization apparatus 4, is introduced into the dilution chamber 46, and pure water is introduced into the concentration chamber 45, the anode chamber 47, and the cathode chamber 48. While the liquid to be treated flows through the dilution chamber 46, cation components such as organic amine, NH ₄ ⁺ ions, and Na ⁺ ions in the solution permeate the cation exchange membrane (C membrane) 44 and enter the concentration chamber 45. Then, the cation component is concentrated in the concentration chamber 45. Similarly, an anion component such as Cl ⁻ ion permeates the anion exchange membrane (A membrane) 43, moves to the concentration chamber 45, and is concentrated in the concentration chamber 45.

Some of the concentrate discharged from the concentrating chamber 45, in order to increase the concentration rate, the pump P ₄ via the concentrated liquid circulation tank 49 is circulated to the inlet side of the concentrating compartment 45, the remainder being industrial waste receiving tank (industrial waste Receiving tank 13). Accordingly, pure water corresponding to the concentrated liquid discharged out of the system is introduced into the concentrating chamber 45 as makeup water.

  Of the concentrated liquid discharged from the concentrating chamber 45, the amount of the circulating liquid circulated to the inlet side of the concentrating chamber 45 is appropriately determined according to the target concentration and processing efficiency. It is preferable to make it about 1 to 20% of the total concentrated liquid discharged.

The dilution water discharged from the dilution chamber 46 is obtained by separating and removing the cation component and the anion component in the neutralization desalination treatment liquid that is the liquid to be treated, and is discharged by the pump P ₅ through the treatment water tank 5. However, in the present invention, this diluted water may be supplied to the catalytic oxidation device 10 and used for the catalytic oxidation treatment together with the alkaline waste liquid. Moreover, this dilution water can also be used as the electrode water of an electrodeionization apparatus (or electrodialysis apparatus) and / or the pure water introduce | transduced into a concentration chamber. Furthermore, it can also be used as pure water for preparing an alkaline solution used in the neutralization dialysis apparatus 2.

Electrode chamber wastewater discharged from the anode chamber 47 and the cathode chamber 48 is mixed with anode water and cathode water, and then subjected to appropriate treatment as necessary, discharged and discharged, or reused for electrode chamber water supply. However, for the following reasons, when the electrode water is circulated and used in order to avoid intrusion of Cl ⁻ ions into the anode chamber 47, only the anodic water is circulated without mixing the anode water and the cathode water. It is preferable to make it. The anode water may be pure water or an alkaline solution, for example, an alkaline aqueous solution such as NaOH of about 0.1 to 1N.

In the electrodeionization apparatus or the electrodialysis apparatus, not only cations but also anion components are moved as ions to be removed, so Cl ⁻ ions enter the concentration chamber. When the Cl ⁻ ion comes into contact with the anode, it undergoes an anodic oxidation reaction and becomes hypochlorous acid having an oxidizing power, which degrades the ion exchange resin and the ion exchange membrane. When the Cl ⁻ concentration in the neutralized desalting treatment solution is low, the influence is small. However, even in the neutralization desalting treatment solution subjected to the neutralization desalting treatment in the present invention, the Cl ⁻ concentration is usually 10 to 10. It is still a high concentration of 20 g / L. For this reason, the anode chamber 47 and the concentrating chamber 45 or dilution chamber 46 adjacent to the anode chamber 47 are separated by a cation exchange membrane (may be a piper membrane), and an oxidizing substance or a substance that becomes oxidizing by anodizing. Therefore, it is preferable that the anode water does not contain such a substance. Therefore, the anode chamber 47 does not contain such a substance. When water or an alkaline solution is supplied and anodic water is circulated, it is preferable to circulate only in the anode chamber.

  FIG. 3 shows an example of an electrodeionization apparatus suitable as a concentrator in the present invention, and the electrodeionization apparatus used in the present invention is not limited to the illustrated one.

For example, the number and arrangement of the concentration chambers and dilution chambers are not particularly limited, and more concentration chambers and dilution chambers may be provided. Further, as shown in FIG. The electrodeionization apparatus 4A provided one by one may be used. Even in this electrodeionization apparatus 4A, as in the electrodeionization apparatus 4 of FIG. 3, organic amine, NH ₄ ⁺ ions, Na ⁺ ions, etc. in the neutralization demineralization treatment solution introduced into the dilution chamber 46 The cation component passes through the cation exchange membrane (C membrane) 44 and moves into the concentration chamber 45, and the cation component is concentrated in the concentration chamber 45. Similarly, an anion component such as Cl ⁻ ion permeates the anion exchange membrane (A membrane) 43, moves to the concentration chamber 45, and is concentrated in the concentration chamber 45.

  Further, as the concentrating device, an electrodialyzer having the same configuration as that of the electrodeionization device can be used except that the ion exchanger is not filled in the dilution chamber or the like instead of the electrodeionization device.

  In the electrodialysis apparatus and the electrodeionization apparatus, concentration is performed by the same mechanism based on ion migration. However, for the following reasons, in particular, when the concentration of ions to be removed in the neutralization demineralization treatment solution is low, It is more efficient to use the device.

  That is, since the electric conductivity is different between the liquid to be treated and the dilution water, when an electrodialyzer is used, a current density distribution occurs in the dilution chamber, and current does not easily flow on the outlet side with high resistance. Filling with an ion exchanger such as an ion exchange resin is effective in relaxing the current density distribution. In addition, when the concentration of ions to be removed in the liquid to be treated is low, only the ion exchange membrane surface becomes an adsorption site for ions to be removed in electrodialysis, and sufficient removal efficiency cannot be obtained. On the other hand, in the case of an electrodeionization apparatus, not only the membrane surface but also an ion exchanger such as an ion exchange resin filled in the dilution chamber also serves as an adsorption site for ions to be removed, and the ions to be removed in a wide area. Since it can adsorb | suck, highly efficient removal (dilution, concentration) is attained.

  Furthermore, a distillation concentrator can be used as the concentrator. In this case, it is preferable to concentrate the neutralized desalting solution to such an extent that no salt is precipitated.

  In addition, when concentrating neutralization demineralization processing liquid with an electrodeionization apparatus or an electrodialysis apparatus, the concentration of the cationic water-soluble compound in the neutralization demineralization process liquid that flows into the dilution chamber of the electrodeionization apparatus or electrodialysis apparatus Since the efficiency of the electrodeionization device or the electrodialysis device is reduced when the concentration of the cationic water-soluble compound in the neutralization demineralization treatment solution becomes 1000 mg / L or less, the treatment is interrupted. The desalting treatment liquid may be supplied to a catalytic decomposition treatment apparatus to decompose the cationic water-soluble compound.

  The concentrated liquid (concentrated liquid discharged from the concentration chamber of the electrodeionization apparatus or the electrodialysis apparatus) concentrated by such a concentration apparatus can be processed by thermal decomposition or in-liquid combustion treatment, but prior to that. If necessary, this concentrated solution may be further concentrated. The concentration means in this case is not particularly limited, but it is advantageous in terms of concentration efficiency to use a distillation concentration apparatus, particularly a vacuum distillation concentration apparatus.

  The degree of concentration of the concentrate is not particularly limited, but the concentration of the nonionic / cationic water-soluble compound in the concentrate subjected to thermal decomposition or in-liquid combustion treatment is 25% by weight or more, for example, 40 to 95%. It is preferable to concentrate so that it may become about%. When the nonionic / cationic water-soluble compound is monoethanolamine, it becomes a compound having a flash point when the concentration exceeds 70% by weight. Therefore, the upper limit is preferably 70% by weight from the viewpoint of handling. .

  The condensed water obtained by distillation concentration of the neutralized desalting solution or further concentration of the concentrated solution should be used as pure water to be introduced into the electrode chamber and / or the concentration chamber of the electrodeionization device or electrodialysis device. Can do.

  On the other hand, the dilution water (dilution water discharged from the dilution chamber of the electrodeionization apparatus or electrodialysis apparatus) obtained by concentrating the neutralization demineralization treatment solution with the electrodeionization apparatus or electrodialysis apparatus is The non-ionic / cationic water-soluble compound and other ionic components in the salt treatment solution are separated and removed. As described above, this diluted water is further introduced into the catalytic oxidation apparatus as necessary to form a catalyst. After the oxidation treatment, it can be neutralized and discharged.

[Neutralization and desalination reduction]
The apparatus shown in FIG. 2 uses an alkaline solution having a higher osmotic pressure than the acidic solution containing a nonionic / cationic water-soluble compound as an alkaline solution in the neutralization dialysis apparatus 2, Instead, the apparatus is different from the apparatus shown in FIG. 1 in that the volume reduction treatment is performed together with the neutralization and desalting treatment of the acidic liquid containing the nonionic / cationic water-soluble compound.

  The configuration of the neutralization dialysis apparatus (diffusion dialysis apparatus) 2 used for the neutralization desalting and volume reduction treatment of the raw water is the same as that shown in FIG.

In the neutralization dialysis device 2, the Cl ⁻ ions in the raw water introduced into the raw water chamber 22 pass through the anion exchange membrane 21 and move to the alkaline solution chamber 23, and are desalted. The raw water is neutralized by OH ⁻ ions permeating the anion exchange membrane 21 and moving to the raw water chamber 22. When the osmotic pressure of the alkaline solution is high, dehydration and volume reduction of the raw water are simultaneously performed by transferring water from the raw water chamber 22 side to the alkaline solution chamber 23 side having a high osmotic pressure. The effluent from the raw water chamber 22 is returned to the raw water tank 1 and the raw water is circulated. On the other hand, the effluent from the alkaline solution chamber 23 is also returned to the alkaline solution storage tank 24 and circulated.

  In such neutralization desalination and volume reduction treatment by the neutralization dialysis apparatus 2, it is preferable to adopt the same mode as the neutralization desalination treatment in FIG. 1 except for the following points.

That is, an alkaline solution having a higher osmotic pressure than raw water is used.
As the alkali solution, the total amount of acid consumption needed to neutralize (mg-CaCO ₃₎ may be one or more times of the total amount of the acidic solution alkaline consumption (mg-CaCO _3).
Note that the migration rate of Cl ⁻ and OH ^{− in} the anion exchange membrane is determined by the ease of ion migration represented by the ultimate molar conductivity, and the ultimate molar conductivity of Cl ⁻ and OH ⁻ is 198.3 Scm, respectively. ² · mol ⁻¹ , 76.35 Scm ² · mol ⁻¹ . Therefore, it can be seen that OH ⁻ can easily move 2.6 times as much as Cl ⁻ . Therefore, in order to maintain a high transfer rate of Cl ⁻ from the acidic solution to the alkaline solution side, the OH ⁻ concentration of the alkaline solution should be at least 1 / 2.6 times the Cl ⁻ concentration of the acidic solution. Is desirable.
Basically, in order to make the osmotic pressure of the alkaline solution higher than the osmotic pressure of the raw water by increasing the concentration of alkali (NaOH), the acid consumption of the alkaline solution in terms of calcium carbonate (mg-CaCO ₃ / L) (Alkalinity) is a concentrated alkaline solution that is 1 or more times, especially about 2 to 6 times, especially 3 to 4 times the alkali consumption (mg-CaCO ₃ / L) (acidity) in terms of calcium carbonate of raw water. Preferably there is. If the alkali concentration of the alkaline solution is low, an efficient volume reduction treatment cannot be performed. The higher the alkali concentration of the alkaline solution relative to the acid concentration of the raw water, the more smoothly the water moves and the concentration efficiency of the raw water improves. However, the alkaline solution is 6 times the alkali consumption in terms of its handleability. In the following, it is particularly preferable to set it to 4 times or less.

  Accordingly, in the case where an alkaline waste solution such as the above-mentioned condemi regeneration alkaline waste solution is used as the alkaline solution, when the alkali concentration is insufficient, it is preferable to adjust the concentration by adding an alkali such as NaOH as necessary.

By making the alkali concentration of the alkaline solution high, the difference in osmotic pressure from the raw water can be made sufficiently large, and efficient desolubilization can be achieved. However, an excessively high concentration alkaline solution is easy to handle and anion exchange is used. There is a problem in obtaining the membrane.
Therefore, in the present invention, it is also preferable to increase the osmotic pressure difference from the raw water without dissolving the salt excessively in the alkaline solution and excessively increasing the alkali concentration.

In this case, the salt to be added to the alkaline solution may be a salt that can be obtained at a low cost, and in particular, salts such as NaCl, Na ₂ SO ₄ , KCl, K ₂ SO ₄ , MgCl ₂ , MgSO ₄ , and mixtures thereof. It is done. These salts are suitable because they are not subject to wastewater standards, and are also salts that are not suitable for food and are disposed of as industrial waste.

There is no restriction | limiting in particular in the addition amount of salts to an alkaline solution, The salt concentration of an alkaline solution is higher than the total solubility substance concentration of the acidic liquid which is raw | natural water, and it can use to the upper limit density | concentration which can melt | dissolve salts. There is no restriction | limiting in particular in the salt density | concentration of the alkaline solution containing salts, Although it changes also with kinds of used salt, it is about 10 to 30 weight% normally.
The alkaline solution containing salts may be prepared by dissolving salts in advance in the alkaline solution, or may be prepared by continuously or intermittently adding salts to the alkaline solution during the treatment.

The neutralization desalination and volume reduction treatment are preferably performed until the pH of the resulting neutralization desalination volume reduction treatment liquid (the effluent from the raw water chamber 22) becomes neutral, for example, about 4 to 10.
If the pH of the neutralized desalting and volume reducing treatment solution is less than 3, the neutralizing desalting and volume reducing treatment is insufficient, and the effects of the present invention cannot be sufficiently obtained. When the pH of the neutralization and desalination volume reduction treatment solution is excessively increased, the amount of Na ⁺ ions that pass through the anion exchange membrane 21 from the alkaline solution chamber 23 side and transfer to the raw water chamber 22 side and anion exchange from the raw water chamber 22 side The amount of nonionic / cationic water-soluble compounds that permeate through the membrane 21 and transfer to the alkaline solution chamber 23 increases (as described below, even if an anion exchange membrane, a small amount of cation components and nonionic components are permeated. Is not preferable).

  For the purpose of pH control, a flow-through pH meter is installed in the outflow pipe of the raw water chamber 22 of the neutralization dialysis apparatus 2 to monitor the pH of the effluent in the raw water chamber 22, and this pH value reaches a predetermined value. Then, the feed of the effluent from the raw water chamber 22 may be switched from the raw water tank 1 to the distillation concentrating device 6.

  The flow direction of the raw water in the raw water chamber 22 and the flow direction of the alkaline solution in the alkaline solution chamber 23 in the neutralization dialysis apparatus 2 may be cocurrent or countercurrent. In order to make the outlet water quality close to neutral by making a difference in the acid consumption of the alkaline liquid, it is preferable to use counter-flow water as shown in FIG.

Moreover, although raw water and an alkaline solution can be passed through in a transient manner, in general, sufficient neutralization and osmotic dialysis cannot be performed in a transient manner, and therefore, as shown in FIG. Such circulating water is preferable.
When continuous processing is performed instead of batch processing, raw water is introduced into the raw water tank 1 and the neutralized desalting and volume reducing treatment liquid returned from the raw water chamber 22 of the neutralization dialysis apparatus 2 is supplied to the raw water tank 1. It is preferable that a part of the liquid in the tank is taken out from the raw water tank 1 and used for the next distillation concentration treatment or the like.

  In FIG. 2, the neutralization dialysis apparatus 2 has one raw water chamber 22 and one alkaline solution chamber 23 each formed by a single anion exchange membrane 21. As shown in FIG. 2 below, a plurality of anion exchanges such as an alkaline solution chamber / anion exchange membrane / raw water chamber / anion exchange membrane / alkaline solution chamber / anion exchange membrane / raw water chamber are shown. A plurality of raw water chambers and alkaline solution chambers may be alternately formed by a membrane.

According to the present invention, the neutralization desalting and volume reduction treatment using such a neutralization dialysis apparatus neutralizes the pH to 4 to 10 neutral as described above, and preferably the Cl ⁻ ion concentration. It is possible to obtain a neutralized and desalted and volume-reduced treatment solution that is reduced to 20 to 50% of the Cl ⁻ ion concentration of the raw water and whose volume is reduced to 40 to 80% with respect to the raw water.

  Alkaline waste liquid generated by such neutralization and desalting and volume reduction processing is supplied to the catalytic oxidation apparatus 10 and subjected to catalytic oxidation processing, as in the apparatus shown in FIG.

[Distillation concentration treatment]
The neutralized desalting and volume reducing treatment liquid of raw water (treatment liquid flowing out from the raw water chamber 22 of the neutralization dialysis device 2) is then used to decompose nonionic / cationic water-soluble compounds such as nitrogen compounds in the liquid. However, prior to that, if necessary, the neutralized desalting and volume reducing treatment solution may be further concentrated to increase the concentration of the nonionic / cationic water-soluble compound. The concentration means in this case is not particularly limited, but it is advantageous in terms of concentration efficiency to use a distillation concentration apparatus 6, particularly a vacuum distillation concentration apparatus as shown in FIG.
Moreover, the neutralization desalination volume reduction processing liquid of raw | natural water can also be concentrated by forward osmosis processing.

  The degree of concentration of the neutralized desalting and volume reducing treatment liquid is not particularly limited, but the concentration of the nonionic / cationic water-soluble compound in the obtained concentrated liquid is 25% by weight or more, for example, about 40 to 95% by weight. It is preferable to concentrate so that it becomes. When the nonionic / cationic water-soluble compound is monoethanolamine, it becomes a compound having a flash point when the concentration exceeds 70% by weight. Therefore, the upper limit is preferably 70% by weight from the viewpoint of handling. .

  In addition, the condensed water obtained by distillation concentration of the neutralization desalination volume reduction process liquid can be used as a pure water for alkali solution preparation.

In FIG. 2, the concentrated liquid concentrated by the distillation concentration apparatus 6 is then fed to the in-liquid combustion apparatus 7 to decompose nonionic / cationic water-soluble compounds such as nitrogen compounds according to a conventional method.
This nonionic / cationic water-soluble compound is decomposed in a high-temperature oxidizing or reducing atmosphere, in addition to submerged combustion in which combustion gas is directly injected into waste liquid to perform heat exchange. It is also possible to carry out a fluidized bed combustion process in which a concentrated liquid is supplied and the concentrated liquid is evaporated and decomposed on the surface of the fluidized bed, or a direct combustion process with or without a combustion aid.

  In the case of concentrating the raw water neutralization desalination volume reduction treatment solution by forward osmosis treatment, for example, in the neutralization dialysis apparatus 2 shown in FIG. By switching to the solution and carrying out circulating water as it is, the neutralized desalting and volume reducing treatment solution of the raw water can be further concentrated. In this case, as the salts used in the high salt concentration solution, those exemplified as the salts to be added to the alkaline solution described above can be used, but other salts that can be separated from the liquid by deaeration such as ammonium carbonate are also suitable. Can be used. That is, when a high salt concentration solution in which ammonium carbonate is dissolved at high concentration is passed, water moves from the acidic solution (neutral water desalination and volume reduction treatment solution) side to the high salt concentration solution side by osmotic pressure. Then, along with the forward osmosis treatment of the raw water neutralization desalting and volume reducing treatment liquid, the ammonium carbonate in the liquid diluted by the movement of water can be easily separated as a gas by the degassing membrane. It can be used to prepare a salt concentration solution.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

  In the following, raw water (hereinafter referred to as “simulated raw water”) prepared by adjusting the cation resin regeneration simulated drainage of the condensate demineralizer to the composition shown in Table 2 below was used.

  Further, in the following, neutralization desalting treatment by the neutralization dialysis apparatus is performed by circulating the whole amount of raw water and alkaline solution, but the neutralization desalting treatment in the present invention is not performed at all. It is not limited to a process, You may circulate only a part of raw | natural water and an alkaline solution, and the whole amount may be passed in a transient manner.

[Example 1]
The simulated raw water was neutralized and desalted by passing through a neutralization dialysis apparatus (manufactured by Astom Co., Ltd.) whose wetted surface was coated with polytetrafluoroethylene.
A system diagram of this neutralization dialysis machine is shown in FIG. In FIG. 5, members having the same functions as those shown in FIG.

In this neutralization dialysis apparatus, the liquid to be treated in the raw water tank 1 is introduced into the raw water chamber 22 by the pump P ₁ and then circulated through the raw water tank 1 while the alkaline solution in the alkaline solution storage tank 24 is used as the alkaline solution. The water is circulated through the chamber 23.

Neutralization dialysis was performed as follows.
As the anion exchange membrane 21, an anion exchange membrane “Neocepta AHA” manufactured by Astom Co., Ltd. having excellent acid resistance and alkali resistance was used.
5 L of simulated raw water is put into the raw water tank 1 and circulated through the raw water chamber 22. On the other hand, as an alkaline solution, an NaOH aqueous solution (pH> 14, HCl molar concentration of 0.5 M of raw water) is used as an alkaline solution. 0.6L was prepared, introduced into the alkaline solution chamber 23 of the neutralization dialysis apparatus 2, and circulated through the alkaline solution storage tank 24.

A diaphragm pump was used as the raw water circulation pump P ₁ and the alkaline solution circulation pump P ₂ , and water was passed so that the membrane surface flow rates of the raw water chamber 22 and the alkaline solution chamber 23 were both 6 cm / sec.

_On the outlet side of the raw water pump P1, a pre-filter (security filter) 11 having a pore diameter of 10 μm was provided to remove particulate components in the raw water.

  During this treatment, the pH of the liquid in the raw water tank 1 was measured, and when the pH dropped to 7.0, circulation water flow was stopped.

  Table 3 shows the water quality of the neutralization desalting treatment liquid and the water quality and amount of the alkali solution (alkali waste liquid) after the neutralization desalting treatment.

  The alkaline waste solution after the neutralization desalting treatment was adjusted to pH 11.5, then passed through a catalytic oxidation apparatus and subjected to catalytic oxidation treatment under the following conditions. Table 4 shows the quality and amount of the catalyst-oxidized water thus obtained.

<Catalytic oxidation conditions>
Catalyst: Cobalt-supported catalyst Oxidant: Sodium hypochlorite added 16300mg / L Water temperature: 50 ° C
SV: 1.5
pH: 11.5

  Table 4 shows the quality of the treated water.

[Comparative Example 1]
The alkaline waste liquid obtained by the neutralization desalting treatment of Example 1 was biologically treated under the following conditions. Table 4 shows the quality and amount of the obtained biologically treated water.

<Biological treatment conditions>
Method: Floating method After adjusting to pH 7.2 by adding acid, dilute by adding water, decompose COD components in organic decomposition tank, then nitrify ammonia to nitric acid in nitrification tank, then denitrification tank Nitric acid is denitrified in the tank, then excess COD in the denitrification process is decomposed in the re-aeration tank, and then the floating sludge is settled and separated in the sedimentation tank, and the separated water is taken out as treated water, and the settled sludge is decomposed into organic substances. Returned to the tank.
pH adjustment: organic matter decomposition tank pH 7.2
Nitrification tank pH 7.2
Denitrification tank pH 7.2
MLSS: 4000mg / L
Water temperature: 25 ° C

[Discussion]
In Example 1, the catalytically oxidized treated water satisfied the seawater drainage standards shown in Table 5 below, whereas the biologically treated water of Comparative Example 1 met the nitrogen standards, but the COD component derived from the biological metabolite had The wastewater standard is not achieved. In Comparative Example 1, it is necessary to further remove the COD component with an apparatus such as coagulation, filtration and activated carbon.
Moreover, since the comparative example 1 requires dilution, the amount of discharged water is about 2.5 times as large as that of the example 1, and the number of facilities is also large. From the viewpoint of maintenance and space, the comparative example 1 is It is determined to be inferior to Example 1.

DESCRIPTION OF SYMBOLS 1 Raw water tank 2 Neutralization dialysis apparatus 3 Processed liquid circulation tank 4,4A Electrodeionization apparatus 5 Processed water tank 6 Distillation concentration apparatus 7 Submerged combustion apparatus 10 Catalytic oxidation apparatus 13 Industrial waste receiving tank 21 Anion exchange membrane 22 Raw water chamber 23 Alkaline solution Chamber 24 Alkaline solution storage tank 41 Anode 42 Cathode 43 Anion exchange membrane (A membrane)
44 Cation exchange membrane (C membrane)
45 Concentration chamber 46 Dilution chamber 47 Anode chamber 48 Cathode chamber

Claims (8)

An apparatus for treating an acidic liquid containing a nonionic or cationic water-soluble compound,
The acidic solution is passed through the one chamber separated by the anion exchange membrane into one chamber and the other chamber, and the alkaline solution is passed through the other chamber to neutralize and remove the acidic solution. Neutralizing and desalting equipment for salting;
An apparatus for treating an acidic liquid, comprising: a catalytic oxidation apparatus for catalytically oxidizing an alkaline liquid used for neutralization and desalting in the neutralization and desalting apparatus.   In Claim 1, it has a concentration apparatus which concentrates the neutralization desalination processing liquid neutralized and desalted by the neutralization desalination apparatus, and the diluted liquid generated in the concentration apparatus is used for the neutralization and desalination. A processing apparatus for acidic liquid, wherein the apparatus is subjected to catalytic oxidation by a catalytic oxidation apparatus together with an alkaline liquid used.   3. The acidic liquid treatment apparatus according to claim 2, wherein the concentration apparatus is any one of a distillation concentration apparatus, an electrodeionization apparatus, and an electrodialysis apparatus. An apparatus for treating an acidic liquid containing a nonionic or cationic water-soluble compound,
The acidic solution is passed through the one chamber separated by the anion exchange membrane into one chamber and the other chamber, and an alkaline solution having a higher osmotic pressure than the acidic solution is passed through the other chamber. A neutralization desalting and volume reducing device for neutralizing and desalting the acidic liquid;
An apparatus for treating an acidic liquid, comprising: a catalytic oxidation apparatus that catalytically oxidizes an alkaline liquid used for neutralization and desalting and volume reduction in the neutralization and desalting and volume reducing apparatus. A method for treating an acidic liquid containing a nonionic or cationic water-soluble compound,
The acidic solution is passed through the one chamber separated by the anion exchange membrane into one chamber and the other chamber, and the alkaline solution is passed through the other chamber to neutralize and remove the acidic solution. Neutralizing and desalting step to salt;
And a catalytic oxidation step of catalytically oxidizing the alkaline solution used for neutralization and desalting in the neutralization and desalting step.   6. The method according to claim 5, further comprising a concentration step of concentrating the neutralized and desalted treatment solution neutralized and desalted in the neutralization and desalting step, and diluting the liquid generated in the concentration step into the neutralization and desalting. A method for treating an acidic liquid, characterized by catalytic oxidation in a catalytic oxidation step together with an alkaline liquid used.   7. The method for treating an acidic liquid according to claim 6, wherein the concentration step is a step using any one of a distillation concentration device, an electrodeionization device, and an electrodialysis device. A method for treating an acidic liquid containing a nonionic or cationic water-soluble compound,
The acidic solution is passed through the one chamber separated by the anion exchange membrane into one chamber and the other chamber, and an alkaline solution having a higher osmotic pressure than the acidic solution is passed through the other chamber. Neutralizing and desalting and reducing the volume of the acidic solution by neutralization and desalting;
And a catalytic oxidation step of catalytically oxidizing the alkaline solution used for neutralization desalting and volume reduction in the neutralization desalting and volume reduction step.

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