JPH0810580A - Treatment of mixed waste liquid and device therefor - Google Patents

Abstract

PURPOSE:To recover acid and ammonia in high concns. from a mixed waste liq. contg. the acid and ammonia and to provide a method for treating the mixed waste liq. to reutilize the acid and ammonia and the device therefor. CONSTITUTION:A three-component electrodialyzer 1 for adding either a strong acid or a strong-electrolyte neutral salt 40' to a mixed waste liq. 23 to recover acid and ammonia, a heater 18 for separating the ammonia in a catholyte of the dialyzer 1, a multi-stage cold-water absorber 19 for recovering the separated gaseous ammonia and an acid-cleaning absorption tower 42 for recovering the gaseous ammonia not recovered by the absorber 19 are combined to recover the acid and ammonia in the waste liq. 23 in high concns. Consequently, the output of the waste which have been discharged into the environment is remarkably reduced.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating a mixed waste liquid containing an acid and an alkali generated in various fields of industry, and recovering and recycling the acid and the alkali from the waste liquid. Accordingly, the present invention relates to a waste liquid treatment method and a waste liquid treatment device suitable for reducing the amount of acid or alkali to be discarded into the environment.

[0002]

2. Description of the Related Art Various acids and alkalis are used in plating, regeneration of ion exchange resins, dissolution of metals, washing, etc., and they are treated so as to be finally in a neutralized state. . Conventionally, most of these are stored in a special place by being contained in hardened cement when they are discarded or diluted and then discarded in rivers or the sea, or when waste liquid contains poisonous substances and radioactive substances. It was being done.

However, recently, from the viewpoint of environmental protection, it is required to collect waste, reuse it as a chemical, and reduce the amount of waste dumped as much as possible, and electrodialysis technology is an effective means. The equipment used has come to be used. Among the above electrodialyzers, a treatment method using a three-chamber electrodialyzer capable of recovering a plurality of types of chemicals in wastes by one treatment is being studied because of low equipment cost and ease of treatment.

The principle of the three-chamber type electrodialyzer is shown in, for example, Japanese Patent Laid-Open No. 58-37596, in which the waste liquid is desalted in the central chamber, the acid in the waste liquid is stored in the anode chamber, and the cathode chamber is Since each alkali in the waste liquid can be taken out independently, there is a possibility that it can be reused as an acid and an alkali, and if it can be reused, it will be possible to significantly reduce the amount of waste, and it will be noted as an excellent technology. It was However, consideration for dialysis efficiency was insufficient, and low concentrations of acids and alkalis were recovered.

[0005]

The above-mentioned conventional treatment method and apparatus using the three-chamber type electrodialyzer has the following problems when the alkali is ammonia. The problem to be solved by the invention will be clarified with reference to FIGS. FIG. 3 is a diagram showing the vapor phase partial pressure of ammonia in the liquid phase, FIG. 4 is an explanatory diagram showing the movement of substances in the cathode chamber of three-chamber electrodialysis, and FIG. 5 is the electrolyte concentration and ratio of each reagent. It is a diagram which shows the relationship with electric conductivity.

(1) FIG. 3 shows the gas phase partial pressure of ammonia in the liquid phase. In the figure, the black squares are at 10 ° C., the white squares are at 20 ° C., and the black diamonds are at 25 ° C. Liquid phase concentration [wt%]
The gas phase partial pressure [atm] is such that, although other alkalis such as sodium hydroxide have a very small gas phase partial pressure, ammonia is very large and is easily gasified even when recovered as a liquid. (2) FIG. 4 shows the movement state of substances in the cathode chamber of three-chamber electrodialysis. Hydrogen is generated at the cathode, and ammonia, which is easily gasified even in a static state, is entrained in the hydrogen. Gasification is promoted and it is difficult to recover as a liquid. From the test results, in the treatment method using the conventional three-chamber electrodialysis device, 3 mol / l
It has been confirmed that equilibrium is achieved to some extent, and high-concentration recovery is impossible. (3) In the catholyte, in addition to ammonia, metal ions contained as impurities in the waste liquid, for example, divalent Ca ions,
Exchange is necessary because monovalent Na ions move, combine with the ammonia and are concentrated. At that time, it is necessary to treat and recover the ammonia remaining in the liquid. (4) FIG. 5 shows the relationship between the electrolyte concentration and the specific electric conductivity of each reagent. Since ammonium hydroxide has a very low specific electric conductivity, an appropriate electric current is applied to perform electrodialysis. Therefore, high voltage is required, and current efficiency is low.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and is capable of performing electrodialysis with high current efficiency and having a high concentration from a mixed waste liquid containing ammonia having an extremely high gas phase partial pressure. It is a first object of the present invention to provide a mixed waste liquid treatment method in which the acid and ammonia are recovered as liquids and reused, and the amount of wastes conventionally discharged to the surrounding environment is greatly reduced. A second object of the present invention is to provide a mixed waste liquid treatment apparatus used in the mixed waste liquid treatment method according to the first object.

[0008]

In order to achieve the above-mentioned first object, a mixed waste liquid treatment method including an acid and ammonia using the electrodialysis method according to the present invention is a three-chamber type waste liquid treatment containing an acid and ammonia. In the mixed waste liquid treatment method of independently recovering acid and ammonia by an electrodialysis device,
It is characterized in that the gas generated from the cathode chamber in which ammonia is recovered is introduced into a recovery system to recover the ammonia contained in the gas. Further, it is characterized in that either a strong acid or a neutral salt of a strong electrolyte is added to the cathode chamber liquid. Further, the ammonia-containing liquid added with a strong acid and treated in the cathode chamber is subjected to a heating operation by adding a strong alkali, or the ammonia-containing liquid treated with a strong electrolyte neutral salt and treated in the cathode chamber remains the same. Ammonia gas is separated by performing a heating operation in this state, and the separated ammonia gas is recovered by a recovery system. In addition, the recovery system is characterized in that temperature-controlled water is used as the first stage as the absorbing liquid, and an acid having the same component as the acid contained in the mixed waste liquid is used as the second stage.

In order to achieve the above-mentioned second object, a mixed waste liquid treatment apparatus containing an acid and ammonia using the electrodialysis method according to the present invention is arranged so that the acid and the ammonia are respectively removed from the waste liquid containing the acid and the ammonia. In a mixed waste liquid treatment device including a three-chamber type electrodialysis device that collects independently, a collection system is provided in the latter stage of the three-chamber type electrodialysis device, and the gas generated from the cathode chamber is introduced into this collection system and included in the gas. It is characterized in that it is configured to recover ammonia. Further, the present invention is characterized in that an addition tank for adding either strong acid or neutral salt of strong electrolyte is provided to the cathode chamber liquid. In addition, an ammonia gas separation unit including an addition unit for adding a strong alkali to the ammonia-containing liquid treated in the cathode chamber and a heating unit for heating the ammonia-containing liquid is provided, and the separated ammonia gas is recovered. It is characterized in that it is configured to be collected by the system. The recovery system was composed of a first recovery section using water whose temperature was controlled as an absorption liquid, and a second recovery section using an acid having the same component as the acid contained in the mixed waste liquid as the absorption liquid. It is characterized by.

[0010]

The operation of each of the above technical means is as follows. According to the configuration of the present invention, the electrode gas accompanied by ammonia generated from the cathode chamber where ammonia is recovered is guided to the recovery system, and the ammonia contained in the gas is absorbed by the absorbing liquid and can be recovered as a liquid. The desalted treated water can also be collected. Also, by adding either strong acid or neutral salt of strong electrolyte to the cathode chamber liquid, it is possible to lower the voltage by increasing the electrical conductivity and improve the current efficiency. The vapor phase partial pressure of the ammonia gas can be increased. In addition, a strong alkali is added to the ammonia-containing liquid that has been treated in the cathode chamber with a strong acid added and subjected to a heating operation, and the ammonia-containing liquid that has been treated with a strong electrolyte neutral salt and that has been treated in the cathode chamber remains as it is. The ammonia gas can be separated by the separation unit that performs the heating operation in 1. and the separated gas can be recovered by the recovery system. In the recovery system, a high-concentration ammonia recovery liquid is obtained by the first recovery unit that uses water whose temperature is controlled to a low temperature as the absorption liquid, and the absorption liquid uses the same acid as the acid contained in the mixed waste liquid. The ammonia gas can be almost completely recovered by the second recovery part.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to FIGS. [Embodiment 1] FIG. 1 is a configuration diagram showing a system of a mixed waste liquid treatment method and a mixed waste liquid treatment apparatus containing an acid and ammonia using an electrodialysis method according to an embodiment of the present invention, and FIG. FIG. 3 is a diagram showing the relationship between the solubility of ammonia in water at 1 [atm] and temperature. In FIG.
The thin line shows the prior art mixed waste liquid treatment method and device,
The thick lines show the characteristic parts of the mixed waste liquid treatment method and apparatus according to one embodiment of the present invention.

Further, prior to the mixed waste liquid treatment method and apparatus according to the present invention shown in FIG. 1, a known waste liquid treatment step using the acid and ammonia recovered in this example, and the above-mentioned treatment. Known dilution for diluting and concentrating waste liquid,
It can be used as a closed system connected to the concentration step, and the waste liquid to be treated can be treated, and the recovered acid and ammonia water can be reused in another place. In the present embodiment, the former case will be described, but the present invention is not limited to this. Illustration and description of the known waste liquid treatment step and the known dilution and concentration steps are omitted because they are troublesome.

In FIG. 1, 1 is a three-chamber electrodialysis tank consisting of a desalting chamber, an anode chamber and a cathode chamber, 2 is a cation exchange membrane, 3 is an anion exchange membrane, 4 is a cathode, 5 is an anode, 6 is a desalting chamber, 7 is a cathode chamber, 8 is an anode chamber, 9 is a desalination solution circulation tank, 10 is a catholyte circulation tank, 11 is an anolyte circulation tank, 12 is a treated water recovery tank for receiving treated water, 13 Is a concentrated ammonia recovery tank, 14 is a concentrated acid recovery tank, and 15 is
An untreated mixed waste liquid receiving tank, 16 is an impurity removing device for removing impurities in the mixed waste liquid, 17 is an excess catholyte recovery tank, 18 is a heating separator for separating ammonia contained in the catholyte, and 19 is As a first step, a multi-stage cold water absorption device for recovering ammonia gas, 20 is a treated water concentration meter for measuring the concentration of treated water, 21 is a catholyte concentration meter for measuring that the catholyte has reached the concentration limit, 22 Is an anolyte concentration meter for measuring the concentration of the circulating fluid in the anode chamber, 23 is a mixed waste liquid containing acid and ammonia, 24 is a circulating fluid in a desalting chamber, 25 is an anolyte, 26 is a catholyte, 27 is a three-chamber electrodialysis Desalination chamber supply liquid, 28 is a heater provided in a heating separator, 29 is a concentrated concentrated acid liquid, 30 is temperature-controlled cold water, and 31 is a strong alkaline liquid addition tank for adding a strong alkaline liquid to the heating separator 18. ,
31 'is a strong alkaline liquid, 32 is evaporated ammonia gas, 3
3 is a mixed gas of electrode hydrogen gas and ammonia gas, 34
Is concentrated and recovered ammonium hydroxide, 35 is the excess catholyte which the circulating fluid of the cathode chamber has exceeded, and 36 is the cathode chamber 7 by dialysis.
In the deionization chamber 6, 37 is the deionized water treated in the desalting chamber 6, 38 is the circulating liquid in the anode chamber, 39
Is a circulating fluid of the cathode chamber, 40 is a reagent addition tank of either strong acid or neutral salt of strong electrolyte, 40 'is a reagent of either strong acid or neutral salt of strong electrolyte, 41 is a recovered gas,
42 is an acid washing absorption tower as a second stage for absorbing the ammonia gas which has not been recovered by the multi-stage cold water absorption device 19, and 43 is an acid solution for absorbing the ammonia gas. These devices and members are connected by necessary piping,
A system of a mixed waste liquid treatment method and a mixed waste liquid treatment apparatus including an acid and ammonia using an electrodialysis method according to an embodiment of the present invention is configured. The pipe connection is complicated and will not be described.

A method of treating a mixed waste liquid containing acid and ammonia and a treatment procedure and an operation of the mixed waste liquid treatment apparatus using the electrodialysis method according to one embodiment of the present invention shown in FIG. 1 will be described. The mixed waste liquid 23 containing acid and ammonia, which has flowed into the receiving tank 15 from the lower left in the drawing, flows into the impurity removing device 16, for example, the electrolytic foaming filtration device. In this electrolytic foaming filtration device, impurities that cause deterioration of the membrane are removed during three-chamber electrodialysis. Impurity remover 1
The mixed waste liquid 23 containing the acid and ammonia that has exited 6 is made to flow into the desalination water circulation tank 9, and is sent to the desalination chamber 6 of the three-chamber electrodialysis chamber 1 via the switching valve.

On the other hand, the anolyte solution 25 and the catholyte solution 26 are introduced into the anolyte solution circulation tank 11 and the catholyte solution circulation tank 10, respectively, and are circulated as the anode circulation solution 38 and the cathode circulation solution 39, respectively. Here, when a voltage is applied between the cathode 4 and the anode 5 of the three-chamber electrodialysis tank 1, a current flows between the electrodes 4 and 5, and the positively charged ammonium ions are charged into the cation exchange membrane 2 The negatively charged acid ions pass through the
It passes through the anion exchange membrane 3 and moves to the anode chamber 8.

As a result, the concentration of the mixed waste liquid in the desalting chamber 6 is reduced by the amount of acid ions or ammonia ions that have moved, and desalted water 37 is eventually obtained. After confirming that the desalted water 37 has reached the discharge concentration by the densitometer 20, the valve interlocking with the densitometer 20 is switched and is not sent to the desalination chamber 6 but sent to the treated water recovery tank 12. Furthermore, three-chamber electrodialysis desalination solution 2
7 is returned to the receiving tank 15.

On the other hand, in the anode chamber 8, the anode circulating fluid 3
8 generated oxygen quantitatively, accumulated acid ions and gradually concentrated, and after confirming that the concentration was recovered by the densitometer 22, the valve interlocking with the densitometer 22 was switched and the anode chamber 8 Instead of being sent to the concentrated acid recovery tank 14 from the anolyte circulation tank 11. The recovered concentrated acid 29 is sent again to the preceding step (not shown) for reuse. The generated oxygen is released into the atmosphere.

On the other hand, in the cathode chamber 7, ammonium ions are transferred from the desalting chamber and gradually concentrated. However, since the ammonia has a high gas phase partial pressure in the liquid phase, it reaches a solubility equilibrium at about 3 mol / l under normal pressure,
After that, it does not dissolve and exists in the gas phase. Therefore, an equivalent amount of hydrogen and ammonia gas are generated from the cathode circulating liquid 39. The catholyte circulation liquid 39 flows into the catholyte circulation tank 10 in a gas / liquid mixture state containing hydrogen and ammonia gas, and is separated into gas and liquid in the catholyte circulation tank 10.

The separated liquid-phase cathode circulating liquid 39, which has reached the solubility equilibrium, is confirmed by the densitometer 21 that the solubility equilibrium has been reached, and the interlocking valve is switched to make the cathode chamber 7
However, it was recovered as the cathodic treatment liquid 36 in which ammonia was saturated to a low concentration. On the other hand, hydrogen gas and ammonium gas were separated by a known separation technique, hydrogen gas was released, and ammonium gas was collected and released to such an extent that a bad odor was not generated.

As described above, in the above conventional treatment process, only the high-concentration acid solution is recovered, and ammonia cannot be recovered as the high-concentration liquid, so that the treatment cost cannot be reduced. In addition, the voltage applied between the cathode 4 and the anode 5 is a high voltage as compared with usual appropriate dialysis conditions,
Current efficiency is also low.

In this example, the following characteristic treatment steps and equipment were added to the treatment steps including the conventional three-chamber electrodialysis apparatus. In the first characteristic treatment step, the catholyte 26 that is introduced into the catholyte circulation tank 10 is provided with a reagent addition tank 40 for increasing electric conductivity, and either a strong acid or a strong electrolyte neutral salt is used. Reagent 40 'is added. The reagent 40 'is not particularly limited as long as it has a higher specific electric conductivity than ammonium hydroxide and can be easily separated and removed later, and it can be a strong acid or a strong electrolyte neutral. Either salt or both is acceptable.

The relationship between the electrolyte concentration of each reagent and the specific electric conductivity is shown in FIG. 5 above. The electric conductivity is 100 relative to ammonium hydroxide when the electrolyte concentration is about 3 mol / l. There is a compound in the nitrogen state that is about twice as high, and the catholyte 2
The electrical conductivity of 6 is improved. For example, it was confirmed that when sulfuric acid having a concentration about 1/10 that of ammonium hydroxide was added to ammonium hydroxide, the electric conductivity increased about 20 times. This reduces the applied voltage, improves the current efficiency, and secondarily activates the generation of ammonia gas in the cathode chamber 7, thereby increasing the vapor phase partial pressure of ammonia gas.

In the second characteristic treatment step, a multi-stage cold water ammonia absorption device 19 is installed after the catholyte circulation tank 10, and a mixed gas 33 of hydrogen and ammonia gas from the cathode circulation tank 10 and not shown. By countercurrently contacting the cold water 30 whose temperature is controlled by the control device, the cold water absorbs the ammonia gas. In the conventional technique, as described in the first characteristic treatment step, oxygen is generated as an electrode gas in the anode chamber 8 and hydrogen gas is generated in the cathode chamber 7, but in the cathode chamber 7, the oxygen gas is generated. In addition to hydrogen gas, ammonia that has reached the solubility equilibrium and cannot be completely dissolved in the solution is also gasified. Of these gases, oxygen and hydrogen were released, and ammonia gas was treated so as not to give off a bad odor, and it was impossible to obtain a high concentration of ammonium hydroxide.

In the above process of absorbing only ammonia gas in cold water, the solubilities of ammonia gas and hydrogen gas are ostwald solubility coefficient values (experimental temperature 10
C.) at 406.6 cm ³ , 202.
It is about 1 cm ³ . Therefore, ammonia gas is
Although it has about twice the solubility of hydrogen gas, the solubility when these two types of gas are mixed changes depending on the partial pressure of each gas.

Further, as described above, the solubility of ammonia gas is not relatively high, but is about twice the solubility of hydrogen gas, which is considerably high for making reusable ammonium hydroxide. It is necessary to make the concentration high, for example, about 8 mol / l. To achieve this goal, the ammonia gas partial pressure should be as high as possible,
Keeping the temperature of the cold water to be absorbed low is also an important factor. FIG. 2 shows the relationship between the solubility of ammonia in water and the temperature at a measurement pressure of 1 [atm]. Since the solubility of ammonia in water increases as the temperature decreases, it is preferably controlled to 10 ° C. or lower.

One of the third characteristic treatment steps is to install a heating separator 18 provided with a strong alkaline liquid addition tank 31 and a heater 28 at the subsequent stage of the catholyte circulation tank 10. In the conventional technique, the cathode circulating liquid 39 becomes an excess due to the transfer of water that moves through the cation exchange membrane 2 to the cathode chamber 7. The excess cathode circulating liquid 39 is the excess cathode liquid 35.
For this reason, a new tank (not shown) was provided and stored, and used again as the catholyte 26.

The surplus catholyte 35 and the cathodic treatment liquid 36 saturated with ammonia to the above-mentioned low concentration are added to the reagent circulating bath 40 in the cathode circulation bath 10 during the first characteristic treatment step.
40 'from E.C., ie either a strong acid or a strong electrolyte neutral salt was added. If strong acid is added,
When ammonium hydroxide and ammonium salt are mixed and the strong electrolyte neutral salt is added, ammonium hydroxide and the added strong electrolyte neutral salt are mixed. In order to recover the ammonia in the ammonium hydroxide and the ammonium salt by the multi-stage cold water ammonia absorption device 19,
Must be gasified.

When the ammonia in the ammonium salt is gasified, as described above, the heating separator 18 including the strong alkaline liquid addition tank 31 and the heater 28 is provided at the subsequent stage of the catholyte circulation tank 10. From the strong alkaline liquid addition tank 31 to the heating separator 18, for example, sodium hydroxide 3
Add 1'to replace ammonium ion and separate,
Ammonia gas 32 is generated by heating with the heater 28. In the case of ammonium hydroxide, the excess catholyte solution 35 and the cathodic treatment solution 36 are heated as they are by the heater 28 to generate the ammonia gas 32.

The generated ammonia gas 32 is sent to the absorption device 19, and the same operation as that for the mixed gas 33 is performed on the ammonia gas 32,
Ammonia gas is recovered by the absorption device 19.
And the recovered concentrated ammonium hydroxide 34 obtained
Is stored in the concentrated ammonium recovery tank 13 and reused, so that it is sent again to the preceding step (not shown).

Further, in the other one of the third characteristic treatment steps, the ammonia gas 32 which could not be recovered is present in the treated gas 41 coming out from the multi-stage cold water ammonia absorption device 19. In consideration of the case, the acid cleaning absorption tower 42 is installed in the latter stage of the cold water ammonia absorption device 19. In the acid cleaning absorption tower 42,
The acid is showered, brought into contact with the unrecovered ammonia gas 32, and made to have the same component as the treatment waste liquid. The liquid after this treatment is placed in the receiving tank 15 and is treated again in the three-chamber electrodialysis device 1.

It is an object of the present invention to add the above three characteristic treatment steps to a three-chamber electrodialyzer.
It becomes possible to efficiently perform the treatment of the waste liquid and the high-concentration recovery of ammonia, and reuse the recovered acid and ammonia recovery liquid.

[0032]

As described in detail above, according to the constitution of the present invention, by efficiently separating and recovering a high concentration of reusable acid and ammonia from a mixed waste liquid containing acid and ammonia, By reusing the recovered acid and ammonia recovery solution, the amount of waste generated in the surrounding environment can be greatly reduced, and acid and ammonia produced by electrodialysis can be used to obtain purified water. It is possible to provide a mixed waste liquid treatment method including a device and an apparatus thereof.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a system of a mixed waste liquid treatment method containing an acid and ammonia using an electrodialysis method according to an embodiment of the present invention, and an apparatus thereof.

FIG. 2 is a diagram showing the relationship between the solubility of ammonia in water and temperature.

FIG. 3 is a diagram showing a relationship between a liquid phase concentration of ammonia and a gas phase partial pressure.

FIG. 4 is an explanatory diagram showing movement of substances in a cathode chamber of three-chamber electrodialysis.

FIG. 5 is a diagram showing the specific electric conductivity of each electrolyte.

[Explanation of symbols]

 1 ... Three-chamber electrodialysis tank 2 ... Cation exchange membrane 3 ... Anion exchange membrane 4 ... Cathode 5 ... Anode 6 ... Desalination chamber 7 ... Cathode chamber 8 ... Anode chamber 9 ... Desalination solution circulation tank 10 ... Catholyte circulation Tank 11 ... Anolyte circulation tank 12 ... Treated water recovery tank 13 ... Concentrated ammonia recovery tank 14 ... Concentrated acid recovery tank 15 ... Receiving tank 16 ... Impurity removing device 18 ... Heating separator 19 ... Multi-stage cold water absorbing device 20 ... Desalination Liquid concentration meter 21 ... Catholyte concentration meter 22 ... Anolyte concentration meter 23 ... Mixed waste liquid containing acid and ammonia 24 ... Desalination chamber circulating liquid 25 ... Anolyte 26 ... Catholyte 27 ... Electrodialysis desalination chamber supply liquid 28 ... Heater provided in the heating separator 29 ... Recovered concentrated acid liquid 30 ... Temperature-controlled cold water 31 ... Strong alkaline liquid addition tank 31 '... Added strong alkaline liquid 32 ... Evaporated ammonia gas 33 ... Electrode hydrogen gas and ammonia Mixed gas with gas 34 ... Concentrated and recovered ammonium hydroxide 35 ... Surplus catholyte 36 ... Treated catholyte 37 ... Demineralized water 38 ... Anode chamber circulating liquid 39 ... Cathode chamber circulating liquid 40 ... Reagent addition tank 40 '... Additive reagent 41 ... Treated gas 42 ... Acid cleaning absorber 43 ... Acid solution

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinori Ishii 2-3-1 Kawa, Yokosuka City, Kanagawa Nihon Niclear Clear Fuel Co., Ltd.

Claims (9)

[Claims] 1. A mixed waste liquid treatment method in which an acid and ammonia are independently recovered from a waste liquid containing acid and ammonia by a three-chamber electrodialyzer, and a gas generated from a cathode chamber in which ammonia is recovered is used. A method for treating a mixed waste liquid, which comprises leading to a recovery system and recovering ammonia contained in the gas. 2. The mixed waste liquid treatment method according to claim 1, wherein either a strong acid or a strong electrolyte neutral salt is added to the cathode chamber liquid. 3. The ammonia-containing liquid treated with a strong acid and treated in the cathode chamber is subjected to a heating operation after adding a strong alkali, and ammonia gas is separated and recovered by a recovery system. The method for treating a mixed waste liquid according to 1, 2 4. The ammonia-containing liquid, to which the strong electrolyte neutral salt has been added and which has been treated in the cathode chamber, is subjected to a heating operation in that state to separate the ammonia gas and recover it by a recovery system. Item 1. A mixed waste liquid treatment method according to items 1 and 2. 5. The recovery system is characterized in that water having a controlled temperature is used as an absorption liquid in the first step, and an acid having the same component as the acid contained in the mixed waste liquid is used in the absorption liquid as the second step. The mixed waste liquid treatment method according to any one of claims 1 to 4. 6. A mixed waste liquid treatment device including a three-chamber electrodialysis device for independently recovering acid and ammonia from a waste liquid containing an acid and ammonia, wherein a recovery system is provided at a stage subsequent to the three-chamber electrodialysis device. A mixed waste liquid treatment apparatus, which is provided so that a gas generated from a cathode chamber is introduced into the recovery system to recover ammonia contained in the gas. 7. The mixed waste liquid treatment apparatus according to claim 5, wherein an addition tank for adding either strong acid or strong electrolyte neutral salt to the cathode chamber liquid is provided. 8. An ammonia gas separation unit provided with an addition unit for adding a strong alkali to the ammonia-containing liquid treated in the cathode chamber and a heating unit for heating the contained liquid is provided, and separated by the separation unit. 7. The ammonia gas is configured to be recovered by a recovery system.
7. The mixed waste liquid treatment method according to any of 7. 9. The recovery system comprises a first recovery part in which water whose temperature is controlled is used as an absorption liquid, and a second recovery part in which an acid having the same component as the acid contained in the mixed waste liquid is used in the absorption liquid. 9. The mixed waste liquid treatment device according to claim 6, wherein the mixed waste liquid treatment device comprises: [0001]