Electrodialysis softening and concentrating treatment system for desulfurization wastewater

Abstract

The invention discloses a desulfurization wastewater electrodialysis softening concentration treatment system which comprises a pretreatment module, a softening and filtering module, an electrodialysis concentration module, a crystallization and recovery module, an auxiliary module and a control module which are connected in sequence, the pretreatment module is used for receiving and primarily treating the desulfurization wastewater, removing suspended matters in the desulfurization wastewater and adjusting the pH value of the desulfurization wastewater; the softening and filtering module is used for further removing suspended matters and small particles through chemical reaction and filtration; the electrodialysis concentration module separates salt through an electric field and an ion exchange membrane to produce fresh water and concentrated water; the crystallization and recovery module is used for recovering salt crystals in the concentrated water; the auxiliary module is used for treating residual concentrated water; and the control module is used for monitoring and controlling operation parameters of the processing system and performing full-process automatic control. Through the synergistic process of pretreatment softening, electrodialysis salt separation, crystallization recovery and flue evaporation, wastewater zero discharge and efficient resource recovery are achieved, and the method has the advantages of being low in cost and high in pollution resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial wastewater treatment, and particularly relates to an electro-dialysis softening, concentrating and treating system for desulfurization wastewater, which is applicable to the treatment of desulfurization wastewater in industries such as coal-fired power plants, iron and steel smelting, and pharmaceuticals, especially for the zero discharge and resource recovery of high-salt and high-hardness wastewater. Background Technique

[0002] Desulfurization wastewater is high-salt, high-hardness and high-suspended solids wastewater generated in the wet desulfurization process, containing a large amount of calcium, magnesium, sulfate, chloride ions and heavy metals. And in the treatment of pharmaceutical wastewater, for every 1 kg of antibiotic produced, about 50 - 100 kg of high-concentration organic wastewater is generated. Pharmaceutical wastewater has a complex composition, containing high-concentration organic compounds, heavy metals, residual drugs and other harmful substances. If discharged into natural water bodies without proper treatment, it will affect water quality and the health of aquatic organisms, and cause bacteria in the water to develop drug resistance to drugs.

[0003] Traditional treatment methods such as chemical precipitation can partially remove pollutants, but have the following problems: 1. Large amount of sludge: Chemical precipitation requires the addition of excessive reagents, generating a large amount of sludge, with high treatment costs and easy to cause secondary pollution; 2. Resource waste: Traditional processes cannot effectively recover salts and acids and bases in wastewater, with low resource utilization rate; 3. Severe membrane fouling: Conventional membrane separation technologies (such as reverse osmosis) are prone to membrane scaling due to high-hardness ions, with low operating efficiency and high maintenance costs; 4. Difficulty in zero discharge: Existing technologies are difficult to achieve full-quantification treatment of wastewater, and the remaining concentrated water still needs to be evaporated and crystallized, with high energy consumption and complex equipment.

[0004] In view of the above problems, the present invention proposes a system combining electro-dialysis softening and concentration, crystallization recovery and flue gas evaporation for collaborative treatment, to achieve efficient softening, concentration and resource utilization of desulfurization wastewater in the pharmaceutical industry, and ultimately achieve the zero-discharge goal. Summary of the Invention

[0005] Aiming at the problems proposed in the above background technique, the object of the present invention is: to provide an electro-dialysis softening, concentrating and treating system for desulfurization wastewater, which realizes zero discharge of wastewater and efficient resource recovery through the collaborative processes of pretreatment softening, electro-dialysis salt separation, crystallization recovery and flue gas evaporation, and has the advantages of low cost and strong anti-pollution ability.

[0006] To achieve the above technical object, the technical solution adopted by the present invention is as follows:

[0007] An electro-dialysis softening, concentrating and treating system for desulfurization wastewater includes a pretreatment module, a softening and filtering module, an electro-dialysis concentration module, a crystallization and recovery module, an auxiliary module and a control module connected in sequence;

[0008] The pretreatment module is used to receive and preliminarily treat the desulfurized wastewater, removing the suspended solids and adjusting the pH value of the desulfurized wastewater;

[0009] The softening and filtration module further removes suspended solids and fine particles through chemical reactions and filtration;

[0010] The electrodialysis concentration module separates salts through an electric field and ion exchange membranes, producing fresh water and concentrated water;

[0011] The crystallization and recovery module is used to crystallize and recover the salts in the concentrated water, and separate and recover the acid-base solution;

[0012] The auxiliary module is used to treat the residual concentrated water;

[0013] The control module is used to monitor and control the operating parameters of the treatment system, and perform full-process automatic control.

[0014] Further defined, the pretreatment module includes a pretreatment tank, a softening tank, a pH adjustment device, and a chelating agent dosing tank connected in sequence;

[0015] The pretreatment tank: is used to receive and preliminarily treat the desulfurized wastewater, removing large particle suspended solids, the size of the large particle suspended solids is greater than μm, chemical agents are added to the softening tank for softening treatment to remove the hardness ions in the desulfurized wastewater, the hardness ions include calcium and magnesium hardness ions, the pH adjustment device is used to adjust the pH value of the desulfurized wastewater, and the chelating agent dosing tank is used to prepare a chelating agent, and the chelating agent forms fine flocs with the calcium and magnesium hardness ions in the desulfurized wastewater.

[0016] Further defined, the softening and filtration module includes a reaction tank, a clarifier, and a high-flux filter connected in sequence;

[0017] The reaction tank is used to carry out chemical reactions to remove suspended solids and heavy metal ions in the desulfurized wastewater, the clarifier further removes suspended solids and precipitates in the water through sedimentation, and the high-flux filter is used to further remove small particle suspended solids in the water, and the size of the small particle suspended solids is less than 100μm.

[0018] Further defined, the electrodialysis concentration module includes an electrodialyzer, a fresh water collection tank, and a concentrated water collection tank connected in sequence;

[0019] The electrodialyzer uses an electric field and ion exchange membranes to achieve the concentration and separation of brine, concentrating the salts in the desulfurized wastewater, the fresh water collection tank is used to collect the fresh water treated by the electrodialyzer, and the fresh water can be recycled for the desulfurization system or other industrial water use, the concentrated water collection tank is used to collect the concentrated water treated by the electrodialyzer, and the concentrated water is further treated or utilized for resource recovery.

[0020] Further defined, the crystallization and recovery module includes a crystallization mechanism, a bipolar membrane electrodialysis device, and an acid-base solution recovery tank connected in sequence;

[0021] The crystallization mechanism is used to crystallize the salts in the concentrated water into solid salts. The bipolar membrane electrodialysis device is used to separate and recover the acids and alkalis in the concentrated water, and reuse them for neutralization and pH callback in pretreatment. The acid-base solution recovery tank is used to store the recovered acid-base solution.

[0022] Further defined, the auxiliary module includes a flue gas evaporation device, a dust collector, and a pipeline pump system connected in sequence;

[0023] The flue gas evaporation device is used to treat the concentrated water. The flue gas evaporation device evaporates and crystallizes through high-temperature flue gas, and captures the crystalline salts into fly ash. The dust collector is used to capture the crystalline salts generated during the flue gas evaporation process. The pipeline pump system is used to connect each module and device.

[0024] Further defined, the control module includes a PLC, which real-time monitors the pH value, flow rate, and pressure, and adjusts the chemical dosing amount.

[0025] A desulfurization wastewater treatment method for a desulfurization wastewater electrodialysis softening and concentration treatment system includes the following steps:

[0026] S1: Pretreatment stage, chemically soften to remove calcium and magnesium ions, and adjust the pH to 6.5 - 10;

[0027] S2: Filtration stage, remove suspended solids through a high-flux filter to a turbidity ≤ 5 NTU;

[0028] S3: Electrodialysis concentration stage, separate the salt water under the action of an electric field, reuse the fresh water, and the concentrated water enters the crystallization module;

[0029] S4: Crystallization and recovery stage, the concentrated water is separated into acid and alkali solutions by bipolar membrane electrodialysis, and the remaining salts are crystallized into solid salts;

[0030] S5: Flue gas evaporation stage, the residual concentrated water is evaporated and crystallized by high-temperature flue gas, and the salts are captured in fly ash.

[0031] Further defined, the chelating agent in S1 is EDTA or sodium citrate, and the dosing amount of the chelating agent is 50 - 200 mg / L.

[0032] Further defined, the electrodialysis operating voltage in S2 is 10 - 30 V, and the salt concentration of the concentrated water is 10 - 20 wt%.

[0033] The beneficial effects of the present invention:

[0034] 1. Zero discharge: Through the coordination of electrodialysis concentration and flue gas evaporation, the full quantification treatment of wastewater is realized;

[0035] 2. High resource recovery rate: recycled fresh water is reused, salt is crystallized into industrial salt, and acid-base solution is recycled;

[0036] 3. Strong anti-pollution ability: the combination of pretreatment and softening process significantly reduces the scaling risk of the electrodialysis membrane;

[0037] 4. Low operating cost: automatic control optimizes the dosage of chemicals, reducing energy consumption and manual intervention.

[0038] In summary, through the collaborative processes of pretreatment softening, electrodialysis salt separation, crystallization recovery, and flue gas evaporation, the present invention realizes zero discharge and efficient resource recovery of wastewater in the pharmaceutical industry, and has the advantages of low cost and strong anti-pollution ability. Brief Description of the Drawings

[0039] The present invention can be further illustrated by the non-limiting embodiments given in the drawings;

[0040] Figure 1 It is a system module diagram of an embodiment of an electrodialysis softening and concentration treatment system for desulfurization wastewater of the present invention;

[0041] Figure 2 It is a step flow diagram of an embodiment of an electrodialysis softening and concentration treatment system for desulfurization wastewater of the present invention.

[0042] The main component symbols are explained as follows: pretreatment module 1, softening and filtration module 2, electrodialysis concentration module 3, crystallization and recovery module 4, auxiliary module 5, control module 6. Detailed Embodiments

[0043] In order to enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be further described below in conjunction with the drawings and embodiments. The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0044] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0045] In addition, the descriptions involving "first", "second", etc. in the present invention are for descriptive purposes only, and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] As Figure 1 shown, a desulfurized wastewater electro-dialysis softening and concentration treatment system of the present invention includes a pretreatment module 1, a softening and filtration module 2, an electro-dialysis concentration module 3, a crystallization and recovery module 4, an auxiliary module 5, and a control module 6 that are connected in sequence;

[0047] The pretreatment module 1 is used to receive and preliminarily treat desulfurized wastewater, and remove suspended solids in the desulfurized wastewater and adjust the pH value of the desulfurized wastewater;

[0048] The softening and filtration module 2 further removes suspended solids and fine particles through chemical reactions and filtration;

[0049] The electro-dialysis concentration module 3 separates salts through an electric field and ion exchange membranes to produce fresh water and concentrated water;

[0050] The crystallization and recovery module 4 is used to crystallize and recover salts in the concentrated water, and separate and recover acid and alkali solutions;

[0051] The auxiliary module 5 is used to treat residual concentrated water;

[0052] The control module 6 is used to monitor and control the operating parameters of the treatment system and perform full-process automatic control.

[0053] In the practical application of this embodiment, the pretreatment module 1 includes a pretreatment tank, a softening tank, a pH adjustment device, and a chelating agent dosing tank that are connected in sequence;

[0054] The pretreatment tank: is used to receive and preliminarily treat desulfurized wastewater, and remove large-particle suspended solids. The size of the large-particle suspended solids is greater than 100 μm. Chemical agents are added to the softening tank for softening treatment to remove the hardness ions in the desulfurized wastewater. The hardness ions include calcium and magnesium hardness ions. The pH adjustment device is used to adjust the pH value of the desulfurized wastewater. The chelating agent dosing tank is used to prepare a chelating agent, and the chelating agent forms fine flocs with the calcium and magnesium hardness ions in the desulfurized wastewater.

[0055] In the practical application of this embodiment, the softening and filtering module 2 includes a reaction tank, a clarifier, and a high-flux filter connected in sequence;

[0056] The reaction tank is used for carrying out chemical reactions to remove suspended solids and heavy metal ions in the desulfurization wastewater. The clarifier further removes suspended solids and precipitates in the water through precipitation. The high-flux filter is used to further remove small-particle suspended solids in the water, and the size of the small-particle suspended solids is less than 100 μm.

[0057] In the practical application of this embodiment, the electrodialysis concentration module 3 includes an electrodialyzer, a fresh water collection tank, and a concentrated water collection tank connected in sequence;

[0058] The electrodialyzer uses an electric field and ion exchange membranes to achieve the concentration and separation of brine, concentrating the salts in the desulfurization wastewater. The fresh water collection tank is used to collect the fresh water treated by the electrodialyzer, and the fresh water can be recycled for use in the desulfurization system or other industrial water. The concentrated water collection tank is used to collect the concentrated water treated by the electrodialyzer, and the concentrated water is further treated or utilized for resource recovery.

[0059] In the practical application of this embodiment, the crystallization and recovery module 4 includes a crystallization mechanism, a bipolar membrane electrodialyzer, and an acid-base solution recovery tank connected in sequence;

[0060] The crystallization mechanism is used to crystallize the salts in the concentrated water into solid salts. The bipolar membrane electrodialyzer is used to separate and recover the acids and alkalis in the concentrated water, and recycle them for neutralization and pH adjustment in pretreatment. The acid-base solution recovery tank is used to store the recovered acid-base solution.

[0061] In the practical application of this embodiment, the auxiliary module 5 includes a flue gas evaporation device, a dust collector, and a pipeline pump system connected in sequence;

[0062] The flue gas evaporation device is used to treat the concentrated water. The flue gas evaporation device evaporates and crystallizes through high-temperature flue gas, and captures the crystalline salts into fly ash. The dust collector is used to capture the crystalline salts generated during the flue gas evaporation process. The pipeline pump system is used to connect each module and device.

[0063] In the practical application of this embodiment, the control module 6 includes a PLC, which monitors the pH value, flow rate, and pressure in real time and adjusts the chemical dosing amount.

[0064] A method for treating desulfurization wastewater in a desulfurization wastewater electrodialysis softening and concentration treatment system includes the following steps:

[0065] S1: In the pretreatment stage, calcium and magnesium ions are removed through chemical softening, and the pH is adjusted to 6.5 - 10;

[0066] S2: Filtration stage, removing suspended solids through a high-flux filter until the turbidity ≤ 5 NTU;

[0067] S3: Electrodialysis concentration stage, separating brine under the action of an electric field, reusing fresh water, and sending the concentrated water into the crystallization module;

[0068] S4: Crystallization recovery stage, separating acid and alkali solutions from the concentrated water through bipolar membrane electrodialysis, and crystallizing the remaining salts into solid salts;

[0069] S5: Flue gas evaporation stage, evaporating and crystallizing the residual concentrated water through high-temperature flue gas, and capturing the salts in fly ash.

[0070] In the practical application of this embodiment, the chelating agent in S1 is EDTA or sodium citrate, and the dosage of the chelating agent is 50 - 200 mg / L.

[0071] In the practical application of this embodiment, the operating voltage of electrodialysis in S2 is 10 - 30 V, and the salt concentration of the concentrated water is 10 - 20 wt%.

[0072] Example 1: Treatment of desulfurization wastewater

[0073] 1. Pretreatment: The desulfurization wastewater from a coal-fired power plant enters the pretreatment tank to remove large particulate suspended solids with a size greater than 100 μm. Then, lime is added to the softening tank to remove calcium and magnesium hardness ions in the desulfurization wastewater, adjust the pH value of the desulfurization wastewater to 10, add the chelating agent sodium citrate (100 mg / L) to form fine flocs with calcium and magnesium hardness ions in the wastewater. After softening treatment, remove small particulate suspended solids with a size less than 100 μm through a high-flux filter until the turbidity equals 5 NTU;

[0074] 2. Electrodialysis concentration: The electrodialyzer operates at a voltage of 20 V, separates brine under the action of an electric field, separates fresh water and concentrated water, and the fresh water is reused in the desulfurization system, and the salt concentration of the concentrated water is 15 wt%;

[0075] 3. Crystallization recovery: Sulfuric acid and sodium hydroxide are separated from the concentrated water through bipolar membrane electrodialysis, and the remaining solution is evaporated and crystallized to produce industrial-grade sodium sulfate;

[0076] 4. Flue gas evaporation: Spray the residual concentrated water into the flue gas, evaporate it in the flue gas at 120 °C, and capture the crystalline salts by the dust collector.

[0077] Example 2: Treatment of wastewater in the pharmaceutical industry

[0078] The similarities between Example 2 and Example 1 will not be elaborated. The differences are as follows: Adjust the chelating agent to EDTA (150 mg / L), increase the electrodialysis voltage to 25 V, the salt concentration of the concentrated water reaches 18 wt%, and the crystallization product is a mixture of sodium chloride and sodium sulfate with a purity ≥ 95%. The specific steps are as follows:

[0079] 1. Pretreatment: The wastewater from the pharmaceutical industry enters the pretreatment tank to remove large particulate suspensions with a size greater than 100 μm. Then, lime is added to the softening tank to remove calcium and magnesium hardness ions in the desulfurization wastewater, and the pH value of the desulfurization wastewater is adjusted to 6.5. Chelating agent EDTA (150 mg / L) is added to form fine flocs with calcium and magnesium hardness ions in the wastewater. After softening treatment, small particulate suspensions with a size less than 100 μm are removed by a high-flux filter until the turbidity equals 5 NTU;

[0080] 2. Electrodialysis concentration: The electrodialyzer operates at a voltage of 25 V. Under the action of an electric field, the brine is separated into fresh water and concentrated water. The fresh water is recycled to the desulfurization system, and the salt concentration of the concentrated water is 18 wt%;

[0081] 3. Crystallization recovery: Sulfuric acid and sodium hydroxide are separated from the concentrated water by bipolar membrane electrodialysis. The remaining solution is evaporated and crystallized to produce a mixture of sodium chloride and sodium sulfate with a purity ≥ 95%;

[0082] 4. Flue gas evaporation: The residual concentrated water is sprayed into the flue gas and evaporated in the flue gas at 120 °C. The crystalline salt is captured by the dust collector.

[0083] The above embodiments only exemplarily illustrate the principles and effects of the present invention, rather than limiting the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A desulfurized wastewater electro-dialysis softening and concentration treatment system, characterized in that: It includes a pretreatment module (1), a softening and filtration module (2), an electrodialysis concentration module (3), a crystallization and recovery module (4), an auxiliary module (5) and a control module (6) connected in sequence; The pretreatment module (1) is used to receive and preliminarily treat the desulfurization wastewater, removing the suspended solids in the desulfurization wastewater and adjusting the pH value of the desulfurization wastewater; The softening and filtration module (2) further removes suspended solids and fine particles through chemical reactions and filtration; The electrodialysis concentration module (3) separates salts through an electric field and ion exchange membranes, producing fresh water and concentrated water; The crystallization and recovery module (4) is used to crystallize and recover the salts in the concentrated water, and separate and recover the acid and alkali solutions; The auxiliary module (5) is used to treat the residual concentrated water; The control module (6) is used to monitor and control the operating parameters of the treatment system and perform full-process automatic control.

2. The electro-dialysis softening and concentration treatment system for desulfurized wastewater according to claim 1, wherein: The pretreatment module (1) includes a pretreatment tank, a softening tank, a pH adjustment device and a chelating agent dosing tank connected in sequence; The pretreatment tank: used to receive and preliminarily treat the desulfurization wastewater, removing large particle suspended solids, the size of the large particle suspended solids is greater than 100μm, chemical agents are added to the softening tank for softening treatment to remove the hardness ions in the desulfurization wastewater, the hardness ions include calcium and magnesium hardness ions, the pH adjustment device is used to adjust the pH value of the desulfurization wastewater, and the chelating agent dosing tank is used to prepare chelating agents, and the chelating agents form fine flocs with the calcium and magnesium hardness ions in the desulfurization wastewater.

3. The electro-dialysis softening and concentration treatment system for desulfurized wastewater according to claim 1, wherein: The softening and filtration module (2) includes a reaction tank, a clarifier and a high-flux filter connected in sequence; The reaction tank is used for chemical reactions to remove suspended solids and heavy metal ions in the desulfurization wastewater, the clarifier further removes suspended solids and precipitates in the water through sedimentation, and the high-flux filter is used to further remove small particle suspended solids in the water, the size of the small particle suspended solids is less than 100μm.

4. A desulfurized wastewater electro-dialysis softening and concentration treatment system according to claim 1, characterized in that: The electrodialysis concentration module (3) includes an electrodialyzer, a fresh water collection tank and a concentrated water collection tank connected in sequence; The electrodialyzer uses an electric field and ion exchange membranes to achieve the concentration and separation of brine, concentrating the salts in the desulfurization wastewater, the fresh water collection tank is used to collect the fresh water treated by the electrodialyzer, and the fresh water can be recycled to the desulfurization system or other industrial water uses, the concentrated water collection tank is used to collect the concentrated water treated by the electrodialyzer, and the concentrated water is further treated or recycled.

5. A desulfurized wastewater electro-dialysis softening and concentration treatment system according to claim 1, characterized in that: The crystallization and recovery module (4) includes a crystallization mechanism, a bipolar membrane electrodialyzer and an acid and alkali solution recovery tank connected in sequence; The crystallization mechanism is used to crystallize the salts in the concentrated water into solid salts, the bipolar membrane electrodialyzer: used to separate and recover the acid and alkali in the concentrated water, and recycle them for neutralization and pH callback in pretreatment, and the acid and alkali solution recovery tank is used to store the recovered acid and alkali solutions.

6. The electro-dialysis softening and concentration treatment system for desulfurized wastewater according to claim 1, wherein: The auxiliary module (5) includes a flue gas evaporation device, a dust collector and a pipeline pump system connected in sequence; The flue gas evaporation device is used to treat concentrated water. The flue gas evaporation device evaporates and crystallizes through high-temperature flue gas, and traps the crystalline salts into fly ash. The dust collector is used to trap the crystalline salts generated during the flue gas evaporation process. The pipeline pump system is used to connect each module and device.

7. A desulfurized wastewater electro-dialysis softening and concentration treatment system according to claim 1, characterized in that: The control module (6) includes a PLC, which real-time monitors the pH value, flow rate and pressure, and adjusts the chemical dosing amount.

8. A method for treating desulfurized wastewater in a desulfurized wastewater electro-dialysis softening and concentration treatment system according to any one of claims 1-7, characterized in that, It includes the following steps: S1: Pretreatment stage, removing calcium and magnesium ions through chemical softening, and adjusting the pH to 6.5 - 10; S2: Filtration stage, removing suspended solids through a high-flux filter until the turbidity ≤ 5 NTU; S3: Electrodialysis concentration stage, separating brine under the action of an electric field, reusing fresh water, and the concentrated water enters the crystallization module; S4: Crystallization recovery stage, separating acid and alkali solutions from the concentrated water through bipolar membrane electrodialysis, and the remaining salts crystallize into solid salts; S5: Flue gas evaporation stage, evaporating and crystallizing the residual concentrated water through high-temperature flue gas, and trapping the salts in fly ash.

9. The desulfurization wastewater treatment method of the desulfurization wastewater electro-dialysis softening and concentration treatment system according to claim 8, characterized in that: The chelating agent in S1 is EDTA or sodium citrate, and the dosing amount of the chelating agent is 50 - 200 mg / L.

10. The desulfurization wastewater treatment method of the desulfurization wastewater electro-dialysis softening and concentration treatment system according to claim 8, characterized in that: The operating voltage of the electrodialysis in S2 is 10 - 30 V, and the salt concentration of the concentrated water is 10 - 20 wt%.

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