A high-salinity wastewater treatment method and a high-salinity wastewater treatment device

Abstract

The embodiment of the application relates to a high-salinity wastewater treatment method and a high-salinity wastewater treatment device. Through bipolar membrane electrodialysis-electrosorption treatment of wastewater, high-salinity ions in the wastewater can be effectively separated and recovered, and the concentrations of Cl ‑ , SO4 2‑ , H2PO4 ‑ , etc. are reduced. The bipolar membrane electrodialysis-electrosorption combination has a wide applicable desalination concentration range, is convenient to operate, has low operation cost, can recycle and reuse resources in the wastewater, can reduce the toxicity of the wastewater, and can reduce the interference of ions in the subsequent Fenton reaction process. Through mixing of the first mixed solution and a magnetic iron-based heterogeneous catalyst, metal ions in the wastewater are reduced and toxic pollutants are degraded through the Fenton reaction, the biodegradability of the wastewater is improved, the COD value of the wastewater is reduced, and the wastewater is low-toxic and meets the discharge standard.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and in particular to a method and apparatus for treating high-salinity wastewater. Background Technology

[0002] In recent years, with the rapid development of my country's national economy, industries such as dyeing and printing, papermaking, chemicals, oil refining, and seawater utilization have generated large amounts of high-salinity wastewater. Direct or diluted discharge of this wastewater not only wastes water resources but also severely impacts the environment. At best, it accelerates eutrophication of rivers and lakes, creating black and odorous water bodies; at worst, it causes the collapse of soil and other ecosystems. However, with industrial development, emerging industries are generating more and more high-salinity wastewater, with increasingly complex compositions and higher concentrations. For example, with the rapid development of the new energy vehicle industry, lithium iron phosphate batteries are widely used in this field. The production process of lithium iron phosphate generates large volumes of wastewater containing high concentrations of ammonia nitrogen, sulfate, and phosphate ions. This wastewater not only contains inorganic ions but also recalcitrant pollutants, making it difficult to treat. Therefore, research on effective treatment methods for high-salinity wastewater is urgently needed.

[0003] Currently, high-salinity wastewater is often treated using methods such as electrolysis and ion exchange. However, these methods are not very effective at degrading inorganic ions and organic pollutants in the wastewater, and they are also costly and have significant limitations. Summary of the Invention

[0004] The embodiments of this application aim to provide a method and apparatus for treating high-salinity wastewater, so as to improve the problem of poor degradation effect of inorganic ions and organic pollutants in wastewater.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in the embodiments of this application is:

[0006] In a first aspect, embodiments of this application provide a method for treating high-salinity wastewater, comprising: homogenizing and equalizing the wastewater; adding a coagulant and a flocculant to the wastewater, and obtaining a supernatant after sedimentation; subjecting the supernatant to bipolar membrane electrodialysis-electroadsorption treatment to obtain a first mixture; mixing the first mixture with a magnetic iron-based heterogeneous catalyst to obtain a second mixture; and subjecting the second mixture to biochemical treatment.

[0007] In some embodiments, before mixing the first mixture with the magnetic iron-based heterogeneous catalyst, concentrated sulfuric acid is added to the first mixture, the pH of the first mixture is adjusted to 3.0 to 5.0, and hydrogen peroxide is added.

[0008] In some embodiments, the bipolar membrane electrodialysis includes a direct current electric field and a plurality of ion exchange membranes, wherein the plurality of ion exchange membranes are disposed between the positive and negative electrodes of the direct current electric field; the ion exchange membranes include anion exchange membranes and cation exchange membranes.

[0009] Secondly, embodiments of this application also provide a method for preparing a magnetic iron-based heterogeneous catalyst as described in any one of the first aspects, comprising: crushing, grinding, and beneficiating Fe3O4 and FeO to obtain a first powder with a particle size of 200 to 300 mesh; mixing the first powder with a reducing agent and a modifying agent, and subjecting it to a redox reaction at an oxygen-free environment of 800°C to 950°C for 8 to 12 hours to obtain a first solid; and grinding the first solid in an oxygen-free environment to obtain a magnetic iron-based heterogeneous catalyst; wherein the iron content in both Fe3O4 and FeO is greater than 70%, and the mass ratio of Fe3O4:FeO is ≥ 5:1.

[0010] Thirdly, embodiments of this application provide a high-salinity wastewater treatment device, comprising: a feeding zone, a reaction zone, and a separation zone, wherein the reaction zone is disposed between the feeding zone and the separation zone; the feeding zone is used to receive wastewater and the magnetic iron-based heterogeneous catalyst as described in the second aspect. A plurality of annular magnets are attached to the inner wall of the reaction zone, and the magnetic iron-based heterogeneous catalyst is adsorbed onto the plurality of annular magnets. The high-salinity wastewater treatment device further includes a baffle assembly disposed between the separation zone and the reaction zone. The baffle assembly includes a plurality of first baffles and a plurality of second baffles, with a first inclination angle between adjacent first baffles, and a first space formed between the two first baffles. The first space includes a first opening and a second opening that are oppositely arranged and communicate with each other. The first opening communicates with the reaction zone, and the second opening communicates with the separation zone. The second baffle is disposed in the first space and has a first gap with at least one first baffle. The separation zone includes a separator, and the separator includes an electromagnet plate disposed in the separator.

[0011] In some embodiments, a plurality of aerators are also included; the aerators are spaced apart at the bottom of the feeding zone and are used to agitate the wastewater and substances in the feeding zone.

[0012] In some embodiments, the high-salinity wastewater treatment device further includes a reflux member disposed between the separator and the second baffle. The reflux member has a third opening facing the second baffle, and the third opening is used to reflux wastewater and the magnetic iron-based heterogeneous catalyst.

[0013] In some embodiments, the annular magnet is wrapped with PO material, the length of which is L, then 0.3m≤L≤0.5m, and the thickness is d, then 0.01m≤d≤0.02m.

[0014] In some embodiments, the material of the ring magnet includes any one of AlNiCo permanent magnet alloys, IronChromiumCo permanent magnet alloys, permanent magnet ferrites, rare earth permanent magnet materials, and composite permanent magnet materials.

[0015] In some embodiments, the separator further includes a coil wound around the electromagnetic plate.

[0016] Unlike related technologies, this application provides a method and apparatus for treating high-salinity wastewater. By subjecting the wastewater to bipolar membrane electrodialysis-electroadsorption treatment, high-salinity ions in the wastewater can be effectively separated and recovered, and the Cl- content can be reduced. - SO4 2- H2PO4 - Plasma concentration. The combination of bipolar membrane electrodialysis and electroadsorption offers a wide applicable desalination concentration range, convenient equipment operation, and low operating costs. It can both recover and reuse resources from wastewater and reduce wastewater toxicity, minimizing interference from ions during subsequent Fenton reactions. By mixing the first mixed solution with a magnetic iron-based heterogeneous catalyst, the Fenton reaction reduces the content of metal ions and toxic pollutants in the wastewater, improving its biodegradability, lowering the COD value, and achieving low-toxicity and compliant discharge of wastewater. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0018] Figure 1 This is a flowchart of a high-salinity wastewater treatment method provided in an embodiment of this application;

[0019] Figure 2 This is a schematic diagram of the structure of a high-salinity wastewater treatment device provided in an embodiment of this application;

[0020] Figure 3 This is a schematic diagram of the structure of a baffle assembly provided in an embodiment of this application.

[0021] 100. High-salinity wastewater treatment equipment;

[0022] 10. Feeding area; 11. Aerator;

[0023] 20. Reaction zone; 21. Ring magnet;

[0024] 30. Separation zone; 31. Separator; 311. Electromagnetic plate;

[0025] 40. Baffle assembly; 41. First baffle; 42. Second baffle; 43. First space; 431. First opening; 432. Second opening; 44. First gap;

[0026] 50. Return component; 51. Third opening; 52. Collection space;

[0027] 60. Water outlet. Detailed Implementation

[0028] To facilitate understanding of the present invention, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "bottom," etc., used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0030] It should be noted that, unless there is a conflict, the various features in the embodiments of this application can be combined with each other, all of which are within the protection scope of this application. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that shown in the flowchart.

[0031] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] In this embodiment, the term "wastewater" or similar terms are used to generally refer to water bodies containing various pollutants that require treatment to avoid pollution problems, without specifying their specific source or the pollutants they contain.

[0033] Firstly, such as Figure 1 As shown, Figure 1 This is a flowchart of a high-salinity wastewater treatment method provided in an embodiment of this application. The method includes:

[0034] Step S1: Homogenize and equalize the wastewater.

[0035] The wastewater in this application embodiment is mainly industrial wastewater, which is mostly high-salt and difficult-to-degrade wastewater, characterized by high organic matter concentration, high pollutant content, and large variability. High-salt wastewater is easily generated in industries such as printing and dyeing, papermaking, chemical processing, oil refining, and seawater utilization. In particular, high-chlorine and high-phosphorus wastewater contains Cl... - CO3 2- H2PO4 - HCO3 - SO4 2- and NO3 - Plasma. Salt concentrations range from 10,000 ppm to 35,000 ppm.

[0036] By treating wastewater to equalize its volume and quality, the system can reduce the impact on downstream systems.

[0037] Step S2: Add coagulant and flocculant to the wastewater, and obtain the supernatant after sedimentation.

[0038] The main function of coagulants is to destabilize suspended solids and aggregate them into larger particles through mechanisms such as double-layer compression and charge neutralization, thereby causing them to settle or float to the surface. Examples include aluminum sulfate, ferric chloride, alum, lime, calcium chloride, silicate coagulants, aluminum chloride, ferrous sulfate, dicyandiamide-formaldehyde coagulants, quaternary ammonium salt coagulants, and tannin coagulants.

[0039] Flocculants primarily work by producing flocculent precipitates through chemical reactions, causing suspended solids in water to form easily precipitated flocs. Examples include cationic polyacrylamide, anionic polyacrylamide, and nonionic polyacrylamide.

[0040] Step S3: Perform bipolar membrane electrodialysis-electroadsorption treatment on the supernatant to obtain the first mixture.

[0041] Bipolar membranes are a novel type of ion-exchange composite membrane, typically composed of a cation exchange layer (N-type membrane), a hydrophilic interfacial layer (catalytic layer), and an anion exchange layer (P-type membrane), making them true reactive membranes. Under a direct current electric field, bipolar membranes can dissociate water, yielding hydrogen ions and hydroxide ions on either side of the membrane. Utilizing this characteristic, bipolar membrane electrodialysis systems, combining bipolar membranes with other cation and anion exchange membranes, can convert salts in aqueous solutions into their corresponding acids and bases without introducing new components; this method is called bipolar membrane electrodialysis.

[0042] Electroadsorption technology, also known as capacitive deionization technology, is a novel water treatment technology that utilizes the phenomenon of ion and charged particle adsorption in water on the surface of charged electrodes. This concentrates dissolved salts and other charged substances in the water on the electrode surface, thereby purifying or desalinating the water. Electroadsorption technology has advantages such as low pollution, high energy efficiency, simple operation, and high resource utilization.

[0043] Furthermore, bipolar membrane electrodialysis includes a direct current electric field and several ion exchange membranes, which are positioned between the positive and negative electrodes of the direct current electric field. The ion exchange membranes include anion exchange membranes (AEMs) and cation exchange membranes (CEMs). The interior of the bipolar membrane electrodialysis unit features a hydrophilic interface at the junction of the anion and cation exchange layers, designed to separate and recover sulfates, phosphates, and metal ions from high-salt, recalcitrant wastewater.

[0044] In wastewater treatment, bipolar membrane electrodialysis-electroadsorption (BME-E) utilizes electroadsorption to adsorb ions or molecules by applying a voltage to the electrode surface, thus achieving desalination. This combination of processes offers a wide applicable desalination concentration range, convenient equipment operation, and low operating costs. It allows for the recovery and reuse of resources from wastewater while reducing wastewater toxicity and minimizing interference from ions during subsequent Fenton reactions. Specifically, wastewater treated by BME-E can effectively reduce Cl... - HCO 3- and H2P0 - Interference ions are significantly reduced.

[0045] Furthermore, since some ions can affect the subsequent Fenton reaction, it is necessary to control the concentration of these ions through bipolar membrane electrodialysis-electroadsorption. Specifically, the water quality of the influent is monitored based on data from the measuring module and voltage levels to control the concentration of ions in the first mixed solution. For example, using Cl... - SO4 2- H2PO4 - Using parameters such as [specific parameters], the supernatant was treated with bipolar membrane electrodialysis-electroadsorption to remove SO4 from the first mixture. 2- The concentration range is controlled between 300 ppm and 500 ppm. Due to Cl...- The concentration of H2PO4 - The concentration can be controlled by suppressing the amount of ·OH produced, and the amount of Fe required for the Fenton reaction. 2+ The amount of Cl in the first mixture affects the degradation efficiency of recalcitrant organic matter. - The concentration can be controlled between 1000 ppm and 2000 ppm for H2PO4. - The concentration can be controlled between 0 ppm and 200 ppm.

[0046] Step S4: Mix the first mixture with a magnetic iron-based heterogeneous catalyst to obtain a second mixture, and then subject the second mixture to biochemical treatment.

[0047] Magnetic iron-based heterogeneous catalysts are typically made of iron-based materials and possess magnetic properties. They can be used in magnetic fixed-bed reactors, where the catalyst's position is controlled by a magnetic field, improving catalyst recovery and recycling rates.

[0048] The first mixture is mixed with a magnetic iron-based heterogeneous catalyst to reduce metal ions and degrade toxic pollutants in wastewater through the Fenton reaction, thereby improving the biodegradability of wastewater and reducing the COD (Chemical Oxygen Demand) value in wastewater.

[0049] The Fenton reaction is carried out under acidic conditions by adding H2O2 and the catalyst Fe to wastewater. 2+ It forms an oxidation system, generating hydroxyl radicals with strong oxidizing power. In aqueous solution, these radicals react with recalcitrant organic matter to form organic free radicals, causing structural damage and oxidative decomposition, effectively removing recalcitrant organic matter from traditional wastewater treatment technologies.

[0050] Furthermore, before mixing the first mixture with the magnetic iron-based heterogeneous catalyst, concentrated sulfuric acid is added to the first mixture to provide the necessary acidic environment for the Fenton reaction. The pH of the first mixture is then adjusted to 3.0 to 5.0, and hydrogen peroxide is added. Hydrogen peroxide is a strong oxidant that provides oxygen atoms for the oxidation reaction, promoting the oxidative degradation of organic matter. In addition, in the Fenton catalytic reaction, the reaction of iron ions and hydrogen peroxide generates hydroxyl radicals, further promoting the degradation of organic matter.

[0051] Biochemical treatment refers to the process of using bioactive substances, such as microorganisms and enzymes, to transform organic matter and other pollutants in wastewater into more stable and environmentally friendly products. Because the Fenton reaction is difficult to remove ammonia nitrogen and total nitrogen from wastewater, biochemical treatment is used to degrade the levels of ammonia nitrogen and total nitrogen. Biochemical treatment typically includes the following methods: contacting wastewater with microorganisms to promote the degradation of organic matter; increasing the dissolved oxygen concentration in the water by agitation or air introduction, thereby promoting microbial growth and metabolic activity; and precipitating solid waste and microorganisms in the wastewater, and then reducing the content of precipitates and organic matter through anaerobic digestion, anaerobic oxidation, etc.

[0052] The high-salinity wastewater treatment method provided in this application embodiment effectively separates and recovers high-salinity ions in the wastewater and reduces Cl- levels by subjecting the wastewater to bipolar membrane electrodialysis-electroadsorption treatment. - SO4 2- H2PO4 - Plasma concentration. The combination of bipolar membrane electrodialysis and electroadsorption offers a wide applicable desalination concentration range, convenient equipment operation, and low operating costs. It can both recover and reuse resources from wastewater and reduce wastewater toxicity, minimizing interference from ions during subsequent Fenton reactions. By mixing the first mixed solution with a magnetic iron-based heterogeneous catalyst, the Fenton reaction reduces the content of metal ions and toxic pollutants in the wastewater, improving its biodegradability, lowering the COD value, and achieving low-toxicity and compliant discharge of wastewater.

[0053] Secondly, embodiments of this application provide a method for preparing a magnetic iron-based heterogeneous catalyst as described in any of the first aspects, comprising: crushing, grinding, and beneficiating Fe3O4 and FeO to obtain a first powder with a particle size of 200 to 300 mesh; mixing the first powder with a reducing agent and a modifying agent, and subjecting it to a redox reaction at an oxygen-free environment of 800°C to 950°C for 8 to 12 hours to obtain a first solid; and grinding the first solid in an oxygen-free environment to obtain a magnetic iron-based heterogeneous catalyst. The iron content in both Fe3O4 and FeO is greater than 70%, and the mass ratio of Fe3O4:FeO is ≥ 5:1. The reducing agent includes pulverized coal, and the modifying agent includes limestone.

[0054] Fe3O4 (iron tetroxide) is an inorganic, magnetic, black crystalline solid that is insoluble in water, alkaline solutions, and organic solvents such as ethanol and ether. It is commonly used as a polishing agent for paint boxes.

[0055] FeO (ferrous oxide) is an inorganic compound and one of the oxides of iron. It appears as a black powder. When heated in air, it is oxidized to iron oxide or magnetite (Fe3O4). When heated in the absence of air, it disproportionates into elemental iron and magnetite.

[0056] The magnetic iron-based heterogeneous catalyst also contains zero-valent iron and a small amount of Fe3O4. The strong oxidizing property of zero-valent iron broadens the applicable pH range of the Fenton reaction and reduces the amount of iron sludge generated. Furthermore, zero-valent iron and Fe3O4 are easy to separate and have high recyclability.

[0057] Thirdly, this application also provides a high-salinity wastewater treatment device 100. Please refer to... Figure 2 The device includes a feeding zone 10, a reaction zone 20, and a separation zone 30, with the reaction zone 20 located between the feeding zone 10 and the separation zone 30.

[0058] The feeding zone 10 is used to receive wastewater and the magnetic iron-based heterogeneous catalyst, as described in the second aspect. Furthermore, several aerators 11 are spaced apart at the bottom of the feeding zone 10, which are used to agitate the wastewater and substances in the feeding zone 10. Both the wastewater and the magnetic iron-based heterogeneous catalyst can enter the feeding zone 10 through different pipes.

[0059] The inner wall of the reaction zone 20 is covered with several ring magnets 21, and the magnetic iron-based heterogeneous catalyst is adsorbed on the ring magnets 21. Furthermore, the ring magnets 21 are wrapped with PO material, the length of which is L, then 0.3m≤L≤0.5m, and the thickness is d, then 0.01m≤d≤0.02m.

[0060] PO (polyolefin) material is a polyolefin copolymer, a polymer obtained from olefin monomers.

[0061] The material of the ring magnet 21 includes any one of the following: AlNiCo permanent magnet alloy, IronChromiumCo permanent magnet alloy, permanent magnet ferrite, rare earth permanent magnet material, and composite permanent magnet material.

[0062] The ring magnet 21 employs a weak magnetic field strength of 840 Gs to 1500 Gs. On one hand, the ring magnet 21 can attract some of the magnetic iron-based heterogeneous catalyst, forming several catalytic reaction bands that complement the flowing catalyst in the reaction zone 20. On the other hand, the ring magnet 21 carries a magnetic field, which magnetizes the wastewater, altering the arrangement of pollutant molecules and water molecules, thus helping hydroxyl radicals overcome the van der Waals forces between water molecules surrounding recalcitrant organic matter. Furthermore, most recalcitrant organic matter is negatively charged, making it easier to move in one direction within the magnetic field. This increases the probability of contact between recalcitrant organic matter and hydroxyl radicals, improving the removal efficiency of organic pollutants and shortening the Fenton reaction time. The HRT (hydraulic retention time) of the wastewater is only 5 to 15 minutes, sufficient to complete the Fenton reaction.

[0063] The magnetic iron-based heterogeneous catalyst is a consumable catalyst. The catalyst adsorbed on the ring magnet 21 needs to be in a dynamic balance of consumption and replenishment at all times to promote the Fenton reaction.

[0064] Please refer to Figure 2 and Figure 3 The high-salt wastewater treatment device 100 also includes a baffle assembly 40, which is disposed between the separation zone 30 and the reaction zone 20. The baffle assembly 40 includes a plurality of first baffles 41 and a plurality of second baffles 42. There is a first inclination angle between two adjacent first baffles 41 and a first space 43 is formed between two first baffles 41. The first space 43 includes a first opening 431 and a second opening 432 that are opposite to each other and communicate with each other. The first opening 431 communicates with the reaction zone 20 and the second opening 432 communicates with the separation zone 30. The second baffle 42 is disposed in the first space 43 and has a first gap 44 between it and at least one first baffle 41.

[0065] Furthermore, the opening size of the first opening 431 is smaller than the opening size of the second opening 432, and the opening size of the first opening 431 formed by the first baffle 41 in the middle position of the baffle assembly 40 is larger than the size of the first opening 431 formed by the first baffles 41 on both sides. When the three-phase mixture comes into contact with the first baffle 41, the water flow rate in the middle position of the three-phase mixture is greater than the water flow rate on both sides, and the flow velocity in the first opening 431 in the middle position is greater than the flow velocity in the first opening 431 on both sides, so that the magnetic iron-based heterogeneous catalyst forms an internal circulation in the baffle assembly 40 with the middle rising and the two sides falling.

[0066] The wastewater is stirred by aerator 11 and other equipment, allowing both the wastewater and catalyst to enter the reaction zone 20 and the separation zone 30. The baffle assembly 40, located between the separation zone 30 and the reaction zone 20, serves to trap, recirculate, and mitigate fluidization disturbances caused by gas oscillations in the wastewater and the magnetic iron-based heterogeneous catalyst. Furthermore, the baffle assembly 40 optimizes the reaction between the wastewater and the catalyst within the reaction zone 20, resulting in a more complete reaction.

[0067] The separation zone 30 includes a separator 31, which includes an electromagnet plate 311 disposed within the separator 31. Further, the separator 31 also includes a coil wound around the electromagnet plate, which is powered by an external power source. When powered, the electromagnet plate 311 becomes magnetic, capable of adsorbing fine catalyst particles in the water. For example, the electromagnet plate 311 can be tilted, which is more conducive to catalyst adhesion. After power is de-energized, the magnetism disappears, and rinsing the electromagnet plate 311 can wash away and recover the magnetic iron-based heterogeneous catalyst particles, achieving solid-liquid separation.

[0068] In some embodiments, the high-salt wastewater treatment device 100 further includes a reflux member 50, which is disposed between the separator 31 and the second baffle 42. The reflux member 50 has a third opening 51 facing the second baffle 42, and the third opening 51 is used to reflux wastewater and magnetic iron-based heterogeneous catalyst.

[0069] In some embodiments, a collection space 52 is provided between the reflux member 50 and the second baffle 42. Specifically, a collection chamber is provided on the surface of the reflux member 50 facing the second baffle 42, and the collection chamber is used to collect the magnetic iron-based heterogeneous catalyst.

[0070] The specific implementation method of the high-salinity wastewater treatment device 100 is as follows:

[0071] Concentrated sulfuric acid is added to the wastewater to adjust the pH to 3.0 to 5.0, and an appropriate amount of hydrogen peroxide is added before it enters the high-salt wastewater treatment unit 100. Please refer to... Figure 2 and Figure 3 After wastewater and magnetic iron-based heterogeneous catalyst enter the feeding zone 10, the wastewater and other substances are mixed and stirred by the aerator 11 at the bottom to form a three-phase mixture. The three-phase mixture rises to the reaction zone 20, where a ring magnet 21 with a magnetic field strength between 840 Gs and 1500 Gs is installed. The three-phase mixture flows through the baffle assembly 40, where the opening 431 formed by the first baffle 41 in the middle position of the baffle assembly 40 is larger than the opening 431 formed by the first baffles 41 on both sides. When the three-phase mixture contacts the first baffle 41, the water flow rate in the middle position is greater than that on both sides, and the flow velocity in the first opening 431 in the middle position is greater than that in the first opening 431 on both sides, causing the magnetic iron-based heterogeneous catalyst to form an internal circulation in the baffle assembly 40, rising in the middle and falling on both sides. The three-phase mixture enters the separation zone 30 after passing through the baffle assembly 40, and the gas is released after passing through the separation zone 30. A portion of the wastewater and magnetic iron-based heterogeneous catalyst enters the collection space 52. Due to collisions and a slowing flow rate, most of the magnetic iron-based heterogeneous catalyst falls freely into the collection chamber. Another portion of the wastewater and magnetic iron-based heterogeneous catalyst flows in a 180° reverse direction into the return member 50. The return member 50 has a third opening 51 facing the second baffle 42, through which some of the wastewater and magnetic iron-based heterogeneous catalyst can be returned to the reaction zone 20. A small amount of fine magnetic iron-based heterogeneous catalyst enters the separator 31 with the wastewater. Under the action of magnetic force, these fine magnetic iron-based heterogeneous catalyst particles are adsorbed onto the electromagnet plate 311. The treated wastewater then continues to rise and enters the outlet 60 for discharge. The discharged water undergoes alkali precipitation and enters the biological treatment process stage. After further reducing pollutants such as COD, ammonia nitrogen, total nitrogen, and total phosphorus in the wastewater, the wastewater achieves low-toxicity discharge standards.

[0072] Fourthly, this application also provides a high-salinity wastewater treatment system, including a wastewater equalization tank, a sedimentation tank, a comprehensive equalization tank, an electrodialysis-electroadsorption device, a high-salinity wastewater treatment device 100, a biochemical treatment device, and a disinfection tank.

[0073] Wastewater equalization tank: Treats wastewater to achieve uniform quality and quantity, reducing the impact on downstream systems. Sedimentation tank: Simultaneously adds flocculants and coagulants to the wastewater to remove suspended solids.

[0074] Integrated equalization tank: Wastewater from the hard sedimentation tank partially settles in the integrated equalization tank, and the collected supernatant enters the electrodialysis-electroadsorption process. It is used to adjust the turbidity, storage capacity, and flow rate of the wastewater to control its residence time within the electrodialysis-electroadsorption system.

[0075] Electrodialysis-electroadsorption unit: Recovers and reuses salt resources in wastewater, reduces wastewater toxicity, and minimizes interference from ions during subsequent Fenton reactions.

[0076] High-salt wastewater treatment device 100: Utilizes a magnetic iron-based heterogeneous catalyst to degrade metal ions and recalcitrant toxic pollutants in wastewater, reduce the COD value of wastewater, and improve the biodegradability of wastewater.

[0077] Biochemical treatment unit: to degrade the content of ammonia nitrogen and total nitrogen.

[0078] Disinfection tank: Kills bacteria, viruses and other microorganisms in the water to ensure the safety and hygiene of the water in order to meet discharge standards.

[0079] To fully illustrate the practical application effects of the high-salinity wastewater treatment method and device provided in the embodiments of this application, the following description is provided in conjunction with specific embodiments:

[0080] Example 1

[0081] Wastewater from a lithium iron phosphate production plant in Yunnan Province is relatively small in volume but contains high concentrations of ammonia nitrogen, sulfate, and phosphate ions. The wastewater has a low organic matter content and is difficult to treat. After undergoing an ammonia stripping process and further treatment by the high-salinity wastewater treatment system provided in this embodiment, the wastewater quality at each process stage is shown in Table 1.

[0082] Table 1: Test data for each process stage

[0083]

[0084] Note: COD is Chemical Oxygen Demand, and SS is the concentration of suspended solids.

[0085] Table 1 shows that the initial wastewater contained 879 mg / L COD, 84 mg / L ammonia nitrogen, 2400 mg / L total nitrogen, 8560 mg / L total salt, 2000 mg / L nitrate, 603 mg / L total hardness, and 1305 mg / L suspended solids (SS). Notably, after electrodialysis-electroadsorption treatment, the total salt content decreased from 6470 mg / L to 4580 mg / L, and subsequent processes maintained the total salt content at around 1600 mg / L. This indicates a significant reduction in total salt content after electrodialysis-electroadsorption treatment of the high-salinity wastewater. After the Fenton reaction, the total nitrogen content in the wastewater decreased from 1820 mg / L to 3.2 mg / L, and combined with the COD, which also decreased from 153 mg / L to 3.2 mg / L after the Fenton reaction. This indicates that the wastewater was mixed using a magnetic iron-based heterogeneous catalyst, which reduced the concentration of organic pollutants in the wastewater through the Fenton reaction and demonstrated a good degradation effect on these pollutants. Based on the effluent standards, the main pollutants in Example 1 all met the effluent standards.

[0086] Example 2

[0087] The wastewater discharged by wool textile enterprises mainly contains wool, detergents, auxiliaries, lanolin, sheep sweat, and silt. It is pale yellow in color and has a foul odor. The wastewater has high levels of salt, CODcr, ammonia nitrogen, total nitrogen, color, and suspended solids (SS), classifying it as high-concentration, recalcitrant organic wastewater. After treatment by the high-salt wastewater treatment system provided in this embodiment, the wastewater quality of each process stage is shown in Table 2.

[0088] Table 2: Test data for each process stage

[0089]

[0090] Note: COD stands for Chemical Oxygen Demand.

[0091] Table 2 shows that the initial wastewater contained 22,000 mg / L COD, 180 mg / L ammonia nitrogen, 300 mg / L total nitrogen, 13,500 mg / L total salt, 200 mg / L total phosphorus, 2,203 mg / L sulfate, and 13,200 mg / L chloride. Before electrodialysis-electroadsorption treatment, the concentrations of COD, total salt, sulfate, and chloride were 9,000 mg / L, 9,900 mg / L, 1,221 mg / L, and 4,050 mg / L, respectively. After electrodialysis-electroadsorption treatment, these concentrations decreased to 5,320 mg / L, 1,840 mg / L, 420 mg / L, and 1,620 mg / L, respectively. This indicates that the total salt and sulfate levels in the high-salt wastewater were significantly reduced after electrodialysis-electroadsorption treatment, demonstrating the effectiveness of this method for treating high-salt solutions. Furthermore, the COD content in the wastewater was 5320 mg / L before the Fenton reaction, and decreased to 335 mg / L after the Fenton reaction, indicating a significant reduction in organic pollutants after the Fenton reaction. The magnetic iron-based heterogeneous catalyst and wastewater treatment equipment provided in this application have a good degradation effect on high-salt and recalcitrant wastewater. Combined with the effluent standards, it can be seen that the main pollutants in Example 2 all meet the effluent standards.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A high-salinity wastewater treatment device, characterized in that, include: The facility includes a feeding zone, a reaction zone, and a separation zone, with the reaction zone located between the feeding zone and the separation zone. The feeding zone is used to receive wastewater and magnetic iron-based heterogeneous catalyst; The inner wall of the reaction zone is covered with several ring magnets, and the magnetic iron-based heterogeneous catalyst is adsorbed on the several ring magnets. The high-salt wastewater treatment device further includes a baffle assembly, which is disposed between the separation zone and the reaction zone. The baffle assembly includes a plurality of first baffles and a plurality of second baffles. There is a first inclination angle between two adjacent first baffles. A first space is formed between two first baffles. The first space includes a first opening and a second opening that are opposite to each other and communicate with each other. The first opening communicates with the reaction zone, and the second opening communicates with the separation zone. The second baffle is disposed in the first space and has a first gap with at least one first baffle. The separation zone includes a separator, and the separator includes an electromagnet plate, which is disposed in the separator. The preparation method of the magnetic iron-based heterogeneous catalyst includes: crushing, grinding, and beneficiating Fe3O4 and FeO to obtain a first powder with a particle size of 200 to 300 mesh; mixing the first powder with a reducing agent and a modifying agent, and performing a redox reaction at an oxygen-free environment of 800°C to 950°C for 8 to 12 hours to obtain a first solid; grinding the first solid in an oxygen-free environment to obtain the magnetic iron-based heterogeneous catalyst; wherein the iron content in both Fe3O4 and FeO is greater than 70%, and the mass ratio of Fe3O4:FeO is ≥ 5:1; the reducing agent includes pulverized coal, and the modifying agent includes limestone.

2. The high-salinity wastewater treatment device according to claim 1, characterized in that, It also includes several aerators; The aerators are spaced apart at the bottom of the feeding zone and are used to stir the wastewater and substances in the feeding zone.

3. The high-salinity wastewater treatment device according to claim 1, characterized in that, It also includes a reflux element, which is disposed between the separator and the second baffle. The reflux element has a third opening facing the second baffle, which is used to reflux wastewater and the magnetic iron-based heterogeneous catalyst.

4. The high-salinity wastewater treatment device according to claim 1, characterized in that, The annular magnet is wrapped with PO material. The length of the PO material is L, then 0.3m ≤ L ≤ 0.5m, and the thickness is d, then 0.01m ≤ d ≤ 0.02m.

5. The high-salinity wastewater treatment device according to claim 1, characterized in that, The material of the ring magnet includes any one of the following: AlNiCo permanent magnet alloy, IronChromiumCo permanent magnet alloy, permanent magnet ferrite, rare earth permanent magnet material, and composite permanent magnet material.

6. The high-salinity wastewater treatment device according to claim 1, characterized in that, The separator also includes a coil wound around the electromagnet plate.

7. A method for treating high-salinity wastewater based on the high-salinity wastewater treatment apparatus according to any one of claims 1 to 6, characterized in that, include: Wastewater is treated to achieve homogenization and equalization of volume; Coagulant and flocculant are added to the wastewater, and the supernatant is obtained after sedimentation. The supernatant was subjected to bipolar membrane electrodialysis-electroadsorption treatment to obtain a first mixture; The first mixture is mixed with a magnetic iron-based heterogeneous catalyst to obtain a second mixture, which is then subjected to biochemical treatment.

8. The method for treating high-salinity wastewater according to claim 7, characterized in that, The bipolar membrane electrodialysis includes a direct current electric field and several ion exchange membranes, wherein the several ion exchange membranes are disposed between the positive and negative electrodes of the direct current electric field. The ion exchange membrane includes anion exchange membranes and cation exchange membranes.

9. The method for treating high-salinity wastewater according to claim 7, characterized in that, Before mixing the first mixture with the magnetic iron-based heterogeneous catalyst, concentrated sulfuric acid is added to the first mixture, the pH of the first mixture is adjusted to 3.0 to 5.0, and hydrogen peroxide is added.

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