Method and device for recycling waste water resources containing organic carnallite

Abstract

The invention relates to the technical field of industrial waste salt treatment in the chemical industry, in particular to a method and a device for recycling waste water resources containing organic carnallite. The invention provides a method for recycling organic matter-containing carnallite wastewater resources. The method comprises the following steps: carrying out air flotation, multi-stage precipitation treatment, multi-stage catalytic oxidation and two-stage nanofiltration on organic matter-containing carnallite wastewater, and crystallizing to obtain sodium chloride and crystallized mirabilite; wherein the pH value of the wastewater containing the organic carnallite is controlled in the air flotation process; a catalyst for primary catalytic oxidation is selected from a nano foam metal iron-based composite catalyst. Wherein the pH value in the air flotation process is controlled, and a specific catalyst is used in the first-stage catalytic oxidation process, so that the concentration of organic matters in the waste water resource containing the organic matter carnallite can be effectively reduced, the efficiency in the subsequent treatment process is effectively improved, the service life of membrane equipment for ultrafiltration, nanofiltration, reverse osmosis and the like is further prolonged, and the treatment cost is reduced. And the content of organic matters in the obtained target product is relatively low.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial waste salt treatment in the chemical industry, and particularly relates to a method and device for resource recovery of wastewater containing organic heterosalt. Background Art

[0002] Wastewater generated in the industrial production processes of industries such as coal chemical industry, petrochemical industry, coking, pesticides, pharmaceuticals, and papermaking contains a large amount of complex and refractory organic substances, as well as acids, bases, salts, etc. During the treatment process, a large amount of waste salt and concentrated waste liquid are generated. Currently, the methods used to treat these waste salts or high-concentration concentrated waste liquids mainly include membrane adsorption, separation, concentration evaporation crystallization, and electrodialysis. For heterosalt with a high organic content, direct incineration method, pyrolysis method, etc. are usually adopted, which have the disadvantages of high energy consumption, large pollution, and high equipment investment, seriously restricting the promotion and application of the methods.

[0003] The Chinese patent "A Method and System for Resource Recovery of Heterosalt" (Patent No. CN114057342A) proposes a method combining pretreatment, catalytic oxidation degradation, ultrafiltration, ion exchange, nanofiltration, reverse osmosis, and evaporation crystallization, realizing the separation and resource recovery of solid heterosalt. The recovered sodium chloride product can meet the physical and chemical indexes of the first-class industrial dry salt in "Industrial Sodium Chloride by-products of Coal Chemical Industry", and the recovered sodium sulfate meets the physical and chemical indexes of Class A first-class products in "Industrial Sodium Sulfate by-products of Coal Chemical Industry". However, the treatment of heterosalt containing organic substances by this system is limited, and the organic content in the target product obtained by its method is relatively high; and the organic content remains at a relatively high level throughout the recovery process, resulting in increased energy consumption and reduced lifespan of membrane equipment such as ultrafiltration membranes, nanofiltration membranes, and reverse osmosis membranes, and affecting the purity of the subsequent obtained products. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problems in the prior art that the organic matter level is relatively high during the resource recovery process of wastewater containing organic heterosalt, resulting in high energy consumption, short lifespan of membrane equipment, and high organic content in the target product, so as to provide a method and device for resource recovery of wastewater containing organic heterosalt.

[0005] The present invention provides a method for resource recovery of wastewater containing organic heterosalt, including the following steps:

[0006] (1) Subjecting the wastewater containing organic heterosalt to air flotation, first precipitation treatment, primary catalytic oxidation, second precipitation treatment, first filtration, secondary catalytic oxidation, cation exchange, second filtration, and primary nanofiltration to obtain primary nanofiltration product water and primary nanofiltration concentrated water;

[0007] (2) The water produced by primary nanofiltration is subjected to secondary nanofiltration to obtain a monovalent salt solution and secondary nanofiltration concentrated water. The monovalent salt solution is subjected to reverse osmosis treatment to obtain a monovalent salt concentrated solution, and the latter monovalent salt concentrated solution is crystallized to obtain crystalline sodium chloride; the secondary nanofiltration concentrated water is returned to the primary nanofiltration process for treatment;

[0008] (3) The primary nanofiltration concentrated water is subjected to tertiary catalytic oxidation and then crystallization treatment to obtain crystalline mirabilite;

[0009] Among them, the pH value of the wastewater containing organic and miscellaneous salts is controlled during the air flotation process; when the wastewater containing organic and miscellaneous salts is acidic, the pH value of the wastewater containing organic and miscellaneous salts is reduced during the air flotation process; when the wastewater containing organic and miscellaneous salts is alkaline, the pH value of the wastewater containing organic and miscellaneous salts is increased during the air flotation process;

[0010] The catalyst for primary catalytic oxidation is selected from nano-foamed metal iron-based composite catalysts.

[0011] It can be understood that the iron in the nano-foamed metal iron-based catalyst is zero-valent iron.

[0012] Optionally, the wastewater containing organic and miscellaneous salts in the present invention comes from wastewater generated by coking, pharmaceutical, printing and dyeing, chemical fertilizer, and pesticide production.

[0013] In one embodiment, the concentration of miscellaneous salts in the wastewater containing organic and miscellaneous salts is 20 - 150 g / L, the TOC content is 30 - 2000 mg / L, and the wastewater containing organic and miscellaneous salts includes chloride ions, sulfate ions, sodium ions, calcium ions, and fluoride ions;

[0014] In one embodiment, the wastewater containing organic and miscellaneous salts further includes at least one of carbonate ions, bicarbonate ions, and magnesium ions.

[0015] Optionally, the TOC content in the wastewater containing organic and miscellaneous salts is 350 mg / L, 500 mg / L, 1000 mg / L, 1500 mg / L, or 1800 mg / L.

[0016] In a specific embodiment, the device for air flotation is selected from any one or a combination of a horizontal flow pressurized dissolved air flotation device, a high-efficiency shallow layer air flotation device, a multiphase mixed dissolution air flotation device, a vortex cavitation air flotation device, and a multistage air flotation device; the working pressure of the air flotation device is 0.1 - 0.4 MPa;

[0017] In a more specific embodiment, the working pressure of the air flotation device is 0.2 - 0.3 MPa.

[0018] In one embodiment, a coagulant, a coagulant aid, a hard water softening agent, and a defluorinating agent are added during the first precipitation treatment and the second precipitation treatment.

[0019] In another embodiment, a bactericide is further added in the first precipitation treatment, and the addition amount of the bactericide is 5-20 ppm.

[0020] In a specific embodiment, the defluorinating agent is selected from polyaluminum chloride;

[0021] In a specific embodiment, the coagulant is selected from one or more of polyaluminum sulfate, polyferric chloride, and polyferric sulfate;

[0022] In a specific embodiment, the coagulant aid is selected from anionic polyacrylamide or cationic polyacrylamide;

[0023] In a specific embodiment, the bactericide is selected from sodium hypochlorite, chlorine dioxide, or hydrogen peroxide;

[0024] In a specific embodiment, the hard water softener is selected from at least one of sodium hydroxide and sodium carbonate.

[0025] In one embodiment, the particle size of the nano-foamed metal iron-based composite catalyst is 1-5 cm, the specific surface area is 5-20 m 2 / g, the pore size distribution range is 10-100 nm, and the average pore size is 20-30 nm; the material of the nano-foamed metal iron-based composite catalyst contains 85-98 wt% of iron;

[0026] In a specific embodiment, the space velocity of the primary catalytic oxidation process is 0.2-2.0 h -1 , and the addition amount of H2O2 is 50-2000 ppm.

[0027] It can be understood that the addition amount of H2O2 is added relative to the volume of the organic matter-containing heterosalt wastewater.

[0028] After the second precipitation treatment, the fine particles and ion concentrations in the organic matter-containing heterosalt wastewater can be reduced; the ions include: chloride ions, sulfate ions, sodium ions, calcium ions, and fluoride ions.

[0029] Optionally, the ions further include carbonate ions, bicarbonate ions, and magnesium ions.

[0030] In a specific embodiment, the filter medium in the first filtration is selected from modified polymer microporous suspended fiber filter cloth filter media particles;

[0031] Among them, the pore size of the filter media particles is 1-60 μm, and the thickness of the filter medium is 1-5 mm.

[0032] Among them, the modified polymer microporous suspended fiber filter cloth filter media particles are purchased from Huade Chuangye.

[0033] In a more specific embodiment, the filtering device in the first filtration is selected from high-speed and high-efficiency filters; wherein the filtering medium in the high-speed and high-efficiency filter is selected from modified polymer microporous suspended fiber filter cloth filter media particles; the pore diameter of the filter media particles is 1-60 μm, and the thickness of the filtering medium is 1-5 mm; the filtering form in the first filtration adopts downward water inlet and upward water outlet, with the filter media above the tank body, naturally forming a filtering area at the top of the tank body and a buffer settling area in the middle and lower parts of the tank body, which has a certain decelerating settling effect on some suspended matters with large particle size and large density. After being buffered by the special distributor baffle at the water inlet, there is no need to decelerate and settle before reaching the filter media layer, and it directly sinks to the bottom or stays in the lower area of the tank body.

[0034] In a more specific embodiment, the filtering device in the first filtration is the Huade Chuangye IAT high-speed precision filter.

[0035] In one embodiment, the turbidity range of the inlet wastewater in the first filtration is 20-200 NTU, the turbidity of the treated wastewater is less than 5 NTU, and the Ca 2+ in the wastewater after the first filtration is below 30 ppm.

[0036] In a specific embodiment, the catalyst used in the secondary catalytic oxidation is a nano-catalyst.

[0037] In a more specific embodiment, the active ingredient of the nano-catalyst is an iron-nickel-copper ternary alloy, the particle size of the active ingredient is 20-30 nm, and the carrier of the nano-catalyst is activated carbon;

[0038] In a more specific embodiment, the space velocity in the secondary catalytic oxidation and the tertiary catalytic oxidation is 0.2-2.0 h -1 , and the addition amount of H2O2 is 50-1000 ppm.

[0039] In one embodiment, the cation exchange resin used in the cation exchange process is selected from styrene-type sulfonic acid cation exchange resin D001 or acrylic acid-type weakly acidic cation exchange resin D113.

[0040] Using only a cation resin tank to replace the ion exchanger can reduce the equipment cost, while reducing the influence on the composition of anions in water and having a higher resource recovery rate.

[0041] In one embodiment, the second filtration is selected from ultrafiltration devices.

[0042] In a more specific embodiment, the ultrafiltration device is selected from the membrane equipment of Hangzhou Kemo Company.

[0043] In a more specific embodiment, the ultrafiltration device is selected from the KM1812-UF small-scale ultrafiltration membrane test equipment of Hangzhou Kemo Laboratory.

[0044] In a specific embodiment, the catalyst used in the three-stage catalytic oxidation is a nano-catalyst.

[0045] In one embodiment, the first-stage nanofiltration device and the second-stage nanofiltration device are connected in series. The membrane flux of the nanofiltration membrane modules of the first-stage nanofiltration device and the second-stage nanofiltration device is 10-30 L / m 2 h, the inlet pressure is 1.5-4 MPa, the water recovery rate of the first-stage nanofiltration product water is 60-90%, and the water recovery rate of the second-stage nanofiltration product water is 80-96%.

[0046] In one embodiment, the method for crystallizing the monovalent salt concentrated solution is selected from evaporation crystallization;

[0047] In one embodiment, the crystallization method in step (3) is selected from freeze crystallization; the crystallization temperature is 0-5°C.

[0048] In freeze crystallization, the temperature is controlled at 0-5°C, and the TOC in the crystallized mirabilite is less than 10 mg / L, and the purity of sodium sulfate is at least 99%.

[0049] The present invention also provides a system for resource recovery of wastewater containing organic heterosalt, including:

[0050] A pretreatment device, including a flotation device and a first sedimentation tank connected in sequence;

[0051] A first-stage catalytic oxidation device, the water inlet of the first-stage catalytic oxidation device is connected to the water outlet of the first sedimentation tank;

[0052] A second sedimentation tank, the water inlet of the second sedimentation tank is connected to the water outlet of the first-stage catalytic oxidation device;

[0053] A first filtration device, the water inlet of the first filtration device is connected to the water outlet of the second sedimentation tank;

[0054] A second-stage catalytic oxidation device, the water inlet of the second-stage catalytic oxidation device is connected to the water outlet of the first filtration device;

[0055] A cation exchange resin device, the water inlet of the cation exchange resin device is connected to the water outlet of the second-stage catalytic oxidation device;

[0056] A second filtration device, the water inlet of the second filtration device is connected to the water outlet of the cation exchange resin device;

[0057] A first-stage nanofiltration device, the water inlet of the first-stage nanofiltration device is connected to the water outlet of the second filtration device; the first-stage nanofiltration device also includes a first-stage nanofiltration product water outlet, a first-stage nanofiltration concentrated water outlet, and a second-stage nanofiltration concentrated water inlet;

[0058] The secondary nanofiltration device, the water inlet of the secondary nanofiltration device is connected to the outlet of the water produced by the primary nanofiltration; the secondary nanofiltration device also includes a monovalent salt solution outlet and a secondary nanofiltration concentrated water outlet; the secondary nanofiltration concentrated water outlet is connected to the secondary nanofiltration concentrated water inlet;

[0059] The tertiary catalytic oxidation device, the water inlet of the tertiary catalytic oxidation device is connected to the outlet of the primary nanofiltration concentrated water;

[0060] The reverse osmosis device, the water inlet of the reverse osmosis device is connected to the monovalent salt solution outlet;

[0061] The sodium chloride evaporation and crystallization device, the water inlet of the sodium chloride evaporation and crystallization device is connected to the outlet of the reverse osmosis device;

[0062] The sodium sulfate freezing and crystallization device, the water inlet of the sodium sulfate freezing and crystallization device is connected to the outlet of the tertiary catalytic oxidation device.

[0063] It can be understood that the outlet of the reverse osmosis device 700 connected to the sodium chloride evaporation and crystallization device 800 is the outlet of the enriched sodium chloride solution; the purified water outlet of the reverse osmosis device 700 can be connected to other devices that require purified water.

[0064] In the invention, the sodium sulfate freezing and crystallization device also includes part of the produced water, which can be used for other process steps.

[0065] The technical solution of the present invention has the following advantages:

[0066] The present invention provides a method for recycling organic matter-containing miscellaneous salt wastewater resources, including the following steps: (1) subjecting the organic matter-containing miscellaneous salt wastewater to air flotation, first precipitation treatment, primary catalytic oxidation, second precipitation treatment, first filtration, secondary catalytic oxidation, cation exchange, second filtration, and primary nanofiltration to obtain primary nanofiltration produced water and primary nanofiltration concentrated water; (2) performing secondary nanofiltration treatment on the primary nanofiltration produced water to obtain a monovalent salt solution and secondary nanofiltration concentrated water, performing reverse osmosis treatment on the monovalent salt solution to obtain a monovalent salt concentrated solution, and crystallizing the latter monovalent salt concentrated solution to obtain crystalline sodium chloride; returning the secondary nanofiltration concentrated water to the primary nanofiltration process for treatment; (3) performing tertiary catalytic oxidation on the primary nanofiltration concentrated water and then performing crystallization treatment to obtain crystalline mirabilite; wherein, the pH value of the organic matter-containing miscellaneous salt wastewater is controlled during the air flotation process; when the organic matter-containing miscellaneous salt wastewater is acidic, the pH value of the organic matter-containing miscellaneous salt wastewater is reduced during the air flotation process; when the organic matter-containing miscellaneous salt wastewater is alkaline, the pH value of the organic matter-containing miscellaneous salt wastewater is increased during the air flotation process; the catalyst for primary catalytic oxidation is selected from a nano-foamed metal iron-based composite catalyst.

[0067] The present invention is directed to the treatment of wastewater containing organic heterosalts for resource recovery. By controlling the pH value during the air flotation process and using a specific catalyst in the primary catalytic oxidation process, the organic matter concentration in the wastewater containing organic heterosalts can be effectively reduced, thereby reducing the influence of organic matter in the subsequent treatment process, effectively improving the efficiency of the subsequent treatment process, and further prolonging the service life of membrane equipment such as ultrafiltration, nanofiltration, and reverse osmosis. Moreover, the organic matter content in the obtained target product is relatively low. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0069] Figure 1 It is a schematic diagram of a system for resource recovery of wastewater containing organic heterosalts in Embodiment 1 of the present invention;

[0070] Reference numerals: 100, air flotation device; 201, first sedimentation tank; 202, second sedimentation tank; 301, primary catalytic oxidation device; 302, secondary catalytic oxidation device; 303, tertiary catalytic oxidation device; 401, first filtration device; 402, second filtration device; 500, cation exchange resin device; 601, primary nanofiltration device; 602, secondary nanofiltration device; 700, reverse osmosis device; 800, sodium chloride evaporation crystallization device; 900, sodium sulfate freezing crystallization device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0071] The following embodiments are provided to better further understand the present invention. They are not limited to the best embodiments, and do not limit the content and protection scope of the present invention. Any product that is the same as or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with those of other prior arts falls within the protection scope of the present invention.

[0072] For those steps or conditions not specified in the embodiments, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For the reagents or instruments not specified by the manufacturer, they are all conventional reagent products that can be obtained through commercial purchase.

[0073] Embodiment 1

[0074] This embodiment provides a system for resource recovery of wastewater containing organic heterosalts, as Figure 1 shown, including:

[0075] The pretreatment device includes a flotation device 100 and a first sedimentation tank 201 connected in sequence;

[0076] A primary catalytic oxidation device 301, the water inlet of the primary catalytic oxidation device 301 is connected to the water outlet of the first sedimentation tank 201;

[0077] A second sedimentation tank 202, the water inlet of the second sedimentation tank 202 is connected to the water outlet of the primary catalytic oxidation device 301;

[0078] A first filtration device 401, the water inlet of the first filtration device 401 is connected to the water outlet of the second sedimentation tank 202;

[0079] A secondary catalytic oxidation device 302, the water inlet of the secondary catalytic oxidation device 302 is connected to the water outlet of the first filtration device 401;

[0080] A cation exchange resin device 500, the water inlet of the cation exchange resin device 500 is connected to the water outlet of the secondary catalytic oxidation device 302;

[0081] A second filtration device 402, the water inlet of the second filtration device 402 is connected to the water outlet of the cation exchange resin device 500;

[0082] A primary nanofiltration device 601, the water inlet of the primary nanofiltration device 601 is connected to the water outlet of the second filtration device 402; the primary nanofiltration device 601 also includes a primary nanofiltration product water outlet, a primary nanofiltration concentrated water outlet, and a secondary nanofiltration concentrated water inlet;

[0083] A secondary nanofiltration device 602, the water inlet of the secondary nanofiltration device 602 is connected to the primary nanofiltration product water outlet; the secondary nanofiltration device 602 also includes a monovalent salt solution outlet and a secondary nanofiltration concentrated water outlet; the secondary nanofiltration concentrated water outlet is connected to the secondary nanofiltration concentrated water inlet;

[0084] A tertiary catalytic oxidation device 303, the water inlet of the tertiary catalytic oxidation device 303 is connected to the concentrated water outlet of the primary nanofiltration device 601;

[0085] A reverse osmosis device 700, the water inlet of the reverse osmosis device 700 is connected to the monovalent salt solution outlet;

[0086] A sodium chloride evaporation crystallization device 800, the water inlet of the sodium chloride evaporation crystallization device 800 is connected to the water outlet of the reverse osmosis device 700;

[0087] A sodium sulfate freezing crystallization device 900, the water inlet of the sodium sulfate freezing crystallization device 900 is connected to the water outlet of the tertiary catalytic oxidation device 303.

[0088] The water outlet connecting the reverse osmosis device 700 in the sodium chloride evaporation and crystallization device 800 is the water outlet for enriching the sodium chloride solution; the purified water outlet of the reverse osmosis device 700 can be connected to other devices that require purified water.

[0089] The wastewater containing organic and miscellaneous salts is introduced into the air flotation device 100 for air flotation, and the treated wastewater after air flotation is introduced into the first sedimentation tank 201 for the first sedimentation treatment; the wastewater after the first sedimentation treatment is introduced into the first-stage catalytic oxidation device 301 for the first-stage catalytic oxidation treatment; the wastewater after the first-stage catalytic oxidation treatment is introduced into the second sedimentation tank 202 for the second sedimentation treatment; the wastewater after the second sedimentation treatment is treated by the first filtration device 401 and then introduced into the first filtration device 401 for the first filtration and then enters the second-stage catalytic oxidation device 302 for the second-stage catalytic oxidation, and then cation exchange is carried out in the cation exchange resin device 500; after cation exchange, the second filtration is carried out in the second filtration device 402; the wastewater after the second filtration is introduced into the first-stage nanofiltration device 601 for the first-stage nanofiltration to obtain the first-stage nanofiltration product water and the first-stage nanofiltration concentrated water; the first-stage nanofiltration product water is introduced into the second-stage nanofiltration device 602 for the second-stage nanofiltration treatment to obtain a monovalent salt solution and the second-stage nanofiltration concentrated water; the second-stage nanofiltration concentrated water is returned to the first-stage nanofiltration device 601 for the first-stage nanofiltration; the monovalent salt solution is introduced into the reverse osmosis device 700 for treatment to obtain a monovalent salt concentrated solution; the monovalent salt concentrated solution is introduced into the sodium chloride evaporation and crystallization device 800 for crystallization to obtain crystalline sodium chloride; the first-stage nanofiltration concentrated water is introduced into the third-stage catalytic oxidation device 303 for the third-stage catalytic oxidation and then introduced into the sodium sulfate freeze crystallization device 900 for crystallization treatment to obtain mirabilite.

[0090] In one embodiment, the air flotation device 100 is any one or a combination of a horizontal flow pressurized dissolved air flotation device, a high-efficiency shallow air flotation device, a multi-component mixed air flotation device, a vortex cavitation air flotation device, and a multi-stage air flotation device. In a specific embodiment, the working pressure of the air flotation device 100 is 0.1 - 0.4 MPa.

[0091] In one embodiment, the first sedimentation tank 201 is selected from high-efficiency sedimentation tanks.

[0092] In one embodiment, the first filtration device 401 is selected from high-speed and high-efficiency filters, and the high-efficiency filter is a high-speed and high-efficiency filter;

[0093] In a more specific embodiment, the high-speed and high-efficiency filter is the Huade Chuangye IAT high-speed precision filter.

[0094] In one embodiment, the second filtration device 402 is selected from ultrafiltration devices.

[0095] In one embodiment, the reverse osmosis device 700 is an ultra-high pressure reverse osmosis device 700

[0096] In a more specific implementation, the ultra-high pressure reverse osmosis device 700 is Xiamen Jiarong.

[0097] It can be understood that an intermediate liquid storage tank can be set up between each device for buffer connection.

[0098] In the subsequent embodiments, the first filtration device 401 used in the first filtration is Huade Chuangye IAT high-speed precision filter (wherein, the pore diameter of the filter media particles is 1-60 μm, and the thickness of the filter medium is 3 mm); the ultrafiltration device in the second filtration is selected from the membrane equipment of Hangzhou Kemao Company (Hangzhou Kemao Laboratory Ultrafiltration Membrane Pilot Equipment KM1812-UF); the reverse osmosis device 700 is Xiamen Jiarong RNF-1800-HP reverse osmosis laboratory equipment; the cation exchange resin used in the cation exchange process is selected from styrene type sulfonic acid cation exchange resin D001.

[0099] Example 2

[0100] In this embodiment, the device provided in Example 1 is used for the resource recovery of organic matter-containing brine wastewater. Among them, the brine concentration of the organic matter-containing brine wastewater is 41.99 g / L, and the water quality index is 6.24 g / L of Na + , 15.93 g / L of Cl - , 13.92 g / L of SO4 2- , 40.4 mg / L of F - , 1.9 g / L of Ca 2+ , 4 g / L of Mg 2+ ; TOC is 487 mg / L; pH is 8;

[0101] Specifically, it includes the following steps:

[0102] (1) The organic matter-containing brine wastewater is introduced into the air flotation device 100 (a horizontal flow pressurized dissolved air flotation device) for air flotation at a pressure of 0.2 MPa. During the air flotation process, the pH value of the organic matter-containing brine wastewater is adjusted to 10 (the pH value is regulated using sodium hydroxide), and the TOC of the wastewater after air flotation is 380 mg / L;

[0103] (2) The wastewater after flotation is introduced into the first sedimentation tank 201 for the first sedimentation treatment. During the first sedimentation process, a coagulant (poly aluminum sulfate), a coagulant aid (anionic polyacrylamide), a hard water softener (sodium hydroxide), a defluorination agent (poly aluminum chloride), and an insecticide (sodium hypochlorite) are added; the total hardness in the wastewater after the first sedimentation treatment is <40 mg / L; Ca 2+ and Mg 2+ total <12 mg / L;

[0104] (3) The wastewater after the first precipitation treatment is introduced into the primary catalytic oxidation device 301 for primary catalytic oxidation treatment; among them, the space velocity in the primary catalytic oxidation process is 0.5 h -1 , the addition amount of H2O2 is 974 ppm (compared with the volume of the wastewater containing organic matter and miscellaneous salts); among them, the catalyst used in the primary catalytic oxidation treatment is a nano-foamed metal iron-based composite catalyst with a particle size of 1-5 cm, a specific surface area of 13 m 2 / g, and an average pore diameter of 4 nm; the material of the nano-foamed metal iron-based composite catalyst contains 85 wt% iron and 15 wt% carbon; the TOC in the wastewater after primary catalytic oxidation is 121.75 mg / L;

[0105] (4) The wastewater after primary catalytic oxidation treatment is introduced into the second sedimentation tank 202 for second sedimentation treatment, and a coagulant (polyaluminum sulfate), a coagulant aid (anionic polyacrylamide), a hard water softener (sodium hydroxide), and a defluorinating agent (polyaluminum chloride) are added during the treatment process;

[0106] (5) The wastewater after the second sedimentation treatment is subjected to the first filtration in the first filtration device 401. The first filtration device 401 used in the first filtration is the Huade Chuangye IAT high-speed precision filter; the turbidity of the inlet wastewater in the first filtration ranges from 27 NTU, and the turbidity of the treated wastewater is 0.3 NTU. The Ca 2+ in the wastewater after the first filtration is less than 30 ppm;

[0107] (6) The wastewater after the first filtration enters the secondary catalytic oxidation device 302 for secondary catalytic oxidation. The catalyst for secondary catalytic oxidation is a nano-catalyst, specifically a nano-nickel-iron alloy catalyst (the active ingredient of the nano-catalyst is a ternary alloy of iron, nickel, and copper, the particle size of the active ingredient is 20-30 nm, and the nano-catalyst carrier is activated carbon). The space velocity in the secondary catalytic oxidation process is 2 h -1 , the addition amount of H2O2 is 200 ppm (compared with the volume of the wastewater containing organic matter and miscellaneous salts); the TOC after secondary catalytic oxidation is 28 mg / L;

[0108] (7) The wastewater after secondary catalytic oxidation is introduced into the cation exchange resin device 500 for cation exchange; among them, the cation exchange resin is a styrene-type sulfonic acid cation exchange resin D001; the wastewater after cation exchange is subjected to the second filtration in the second filtration device 402, and the second filtration is a membrane device of Hangzhou Kemo Company; the Ca+ concentration is reduced from 30 ppm to less than 1 ppm;

[0109] (8) The wastewater after the second filtration is introduced into the primary nanofiltration device 601 for primary nanofiltration to obtain primary nanofiltration product water and primary nanofiltration concentrated water; among them, the membrane flux of the primary nanofiltration membrane is 14.35 L / m 2h; the inlet water pressure is 3.75 MPa; the water production recovery rate is 85%;

[0110] Feed the first-stage nanofiltration produced water into the second-stage nanofiltration device 602 for second-stage nanofiltration treatment to obtain a monovalent salt solution and second-stage nanofiltration concentrated water; among them, the membrane flux of the second-stage nanofiltration membrane is 14.68 L / m 2 h; the inlet water pressure is 2.13 MPa; the water production recovery rate is 85%; after treatment by the first-stage nanofiltration device 601 and the second-stage nanofiltration device 602, the interception rate of TOC is 87.1%; among them, the second-stage nanofiltration concentrated water contains NaCl: 21 g / L; Na2SO4: 128 g / L; return the second-stage nanofiltration concentrated water to the first-stage nanofiltration device 601 for first-stage nanofiltration;

[0111] (9) Feed the monovalent salt solution into the reverse osmosis device 700 for treatment to obtain a monovalent salt concentrated solution; feed the monovalent salt concentrated solution into the sodium chloride evaporation crystallization device 800 for crystallization to obtain crystalline sodium chloride; among them, the reverse osmosis device 700 uses ultra-high pressure reverse osmosis, the pressure is 8 - 12 Mpa, the inlet salt concentration is 35 g / L, the produced water salt concentration is 102 g / L NaCl, and the membrane flux of ultra-high pressure reverse osmosis is 41 - 50 L / m 2 h; the crystal nucleation rate during the evaporation crystallization process is 0.3 mm / h, the evaporation temperature is 60 °C, and NaCl is obtained;

[0112] Feed the first-stage nanofiltration concentrated water into the three-stage catalytic oxidation device 303 for three-stage catalytic oxidation and then into the sodium sulfate freeze crystallization device 900 for crystallization treatment to obtain mirabilite; among them, the catalyst for three-stage catalytic oxidation is a nano-catalyst, specifically a nano nickel-iron alloy catalyst (the active component of the nano-catalyst is a ternary alloy of iron, nickel, and copper, the particle size of the active component is 20 - 30 nm, and the nano-catalyst carrier is activated carbon), the space velocity during the two-stage catalytic oxidation process is 2 h -1 , the addition amount of H2O2 is 200 ppm (compared with the volume of the organic matter-containing miscellaneous salt wastewater); the freeze crystallization temperature is 5 °C, and the freeze crystallization yield is 50%.

[0113] It can be understood that the detection data in Example 2 and subsequent examples are the detection results after the system reaches equilibrium.

[0114] Example 3

[0115] In this example, the device provided in Example 1 is used for the resource recovery of the organic matter-containing miscellaneous salt wastewater. Among them, the salt water concentration of the organic matter-containing miscellaneous salt wastewater is 80 g / L, and the water quality index contains 25.3 g / L of Na + , 35.5 g / L of Cl - , 10.2 g / L of SO4 2- , 4 mg / L of F - , 4.5 g / L of Ca 2+, 2.4 ppm of Mg 2+ , 1.2 g / L of CO3 2- , 0.5 g / L of HCO3 - ; TOC is 1092 mg / L; pH value is 6;

[0116] Specifically, it includes the following steps:

[0117] (1) Feed the wastewater containing organic and miscellaneous salts into the air flotation device 100 (a horizontal flow pressurized dissolved air flotation device) for air flotation at a pressure of 0.25 MPa. During the air flotation process, adjust the pH value of the wastewater containing organic and miscellaneous salts to 5 (the pH value is regulated using hydrochloric acid). The TOC of the wastewater after air flotation is 747 mg / L;

[0118] (2) Feed the wastewater after flotation into the first sedimentation tank 201 for the first sedimentation treatment. During the first sedimentation process, add a coagulant (polyaluminum sulfate), a flocculation aid (anionic polyacrylamide), a hard water softening agent (sodium hydroxide), a defluorinating agent (polyaluminum chloride), and an insecticide (sodium hypochlorite); The total hardness in the wastewater after the first sedimentation treatment is < 50 mg / L; Ca 2+ and Mg 2+ together are < 15 mg / L;

[0119] (3) Feed the wastewater after the first sedimentation treatment into the first - stage catalytic oxidation device 301 for the first - stage catalytic oxidation treatment; Among them, the space velocity during the first - stage catalytic oxidation process is 0.5 h -1 , the addition amount of H2O2 is 974 ppm (compared with the volume of the wastewater containing organic and miscellaneous salts); The catalyst used in the first - stage catalytic oxidation treatment is a nano - foam metal iron - based composite catalyst with a particle size of 1 - 5 cm, a specific surface area of 13 m 2 / g, and an average pore diameter of 4 nm; The material of the nano - foam metal iron - based composite catalyst contains 85 wt% of iron and 15 wt% of carbon; The TOC in the wastewater after the first - stage catalytic oxidation is 103 mg / L

[0120] (4) Feed the wastewater after the first - stage catalytic oxidation treatment into the second sedimentation tank 202 for the second sedimentation treatment. During the treatment process, add a coagulant (polyaluminum sulfate), a flocculation aid (anionic polyacrylamide), a hard water softening agent (sodium hydroxide), and a defluorinating agent (polyaluminum chloride);

[0121] (5) Feed the wastewater after the second sedimentation treatment into the first filtration device 401 for the first filtration. The first filtration device 401 used in the first filtration is the Huade Chuangye IAT high - speed precision filter; The turbidity of the inlet wastewater for the first filtration ranges from 114 NTU, and the turbidity of the treated wastewater is 1 NTU. The Ca in the wastewater after the first filtration 2+ is less than 30 ppm;

[0122] (6) The first filtered wastewater enters the secondary catalytic oxidation device 302 for secondary catalytic oxidation. The catalyst for secondary catalytic oxidation is a nano-catalyst, specifically a nano nickel-iron alloy catalyst (the active ingredient of the nano-catalyst is a ternary alloy of iron, nickel, and copper, the particle size of the active ingredient is 20 - 30 nm, and the nano-catalyst carrier is activated carbon). The space velocity during the secondary catalytic oxidation process is 2 h -1 , and the addition amount of H2O2 is 180 ppm (compared with the volume of the wastewater containing organic matter and miscellaneous salts); the TOC after secondary catalytic oxidation is 30 mg / L;

[0123] (7) The wastewater after secondary catalytic oxidation is passed into the cation exchange resin device 500 for cation exchange; the cation exchange resin is styrene type sulfonic acid cation exchange resin D001; the wastewater after cation exchange is filtered for the second time in the second filtration device 402, and the second filtration is a membrane device of Hangzhou Kemao Company for ultrafiltration; the Ca+ concentration is reduced from 30 ppm to less than 1 ppm;

[0124] (8) The wastewater after the second filtration is passed into the first nanofiltration device 601 for first nanofiltration to obtain first nanofiltration product water and first nanofiltration concentrated water; among them, the membrane flux of the first nanofiltration membrane is 15.5 L / m 2 h; the inlet pressure is 3.75 MPa; the water production recovery rate is 80%;

[0125] The first nanofiltration product water is passed into the second nanofiltration device 602 for second nanofiltration treatment to obtain a monovalent salt solution and second nanofiltration concentrated water; among them, the membrane flux of the second nanofiltration membrane is 15.5 L / m 2 h; the inlet pressure is 5.12 MPa; the water production recovery rate is 85%; the interception rate of TOC after treatment by the first nanofiltration device 601 and the second nanofiltration device 602 is 84.5%; among them, the second nanofiltration concentrated water contains NaCl: 34 g / L; Na2SO4: 137 g / L; the second nanofiltration concentrated water is returned to the first nanofiltration device 601 for first nanofiltration;

[0126] (9) The monovalent salt solution is passed into the reverse osmosis device 700 for treatment to obtain a monovalent salt concentrated solution; the monovalent salt concentrated solution is passed into the sodium chloride evaporation crystallization device 800 for crystallization to obtain crystalline sodium chloride; among them, the reverse osmosis device 700 uses ultra-high pressure reverse osmosis, the pressure is 8 - 12 Mpa, the inlet salt concentration is 45 g / L, the product water salt concentration is 136 g / L NaCl, and the membrane flux of ultra-high pressure reverse osmosis is 41 - 50 L / m 2 h; the crystal nucleation rate during the evaporation crystallization process is 0.5 mm / h, the evaporation temperature is 80 °C, and NaCl is obtained;

[0127] The first-stage nanofiltration concentrated water is introduced into the three-stage catalytic oxidation device 303 for three-stage catalytic oxidation, and then introduced into the sodium sulfate freeze crystallization device 900 for crystallization treatment to obtain mirabilite; the catalyst for the three-stage catalytic oxidation is a nano-catalyst, specifically a nano nickel-iron alloy catalyst (the active ingredient of the nano-catalyst is a ternary alloy of iron, nickel and copper, the particle size of the active ingredient is 20-30 nm, and the nano-catalyst carrier is activated carbon). The space velocity during the three-stage catalytic oxidation process is 2 h -1 , the addition amount of H2O2 is 180 ppm (compared with the volume of the organic matter-containing and salt-containing wastewater); the freeze crystallization temperature is 3 °C, and the freeze crystallization yield is 65%

[0128] Example 4

[0129] In this example, the device provided in Example 1 is used for the resource recovery of the organic matter-containing and salt-containing wastewater. Among them, the brine concentration of the organic matter-containing and salt-containing wastewater is 150 g / L, and the water quality index contains 60.4 g / L of Na + , 49.8 g / L of Cl - , 26.8 g / L of SO4 2- , 4 ppm of F - , 5.3 g / L of Ca 2+ , 1.2 ppm of Mg 2+ , 0.5 g / L of CO3 2- , 6.4 g / L of HCO3 - ; the TOC is 1976 mg / L; the pH value is 8;

[0130] Specifically, it includes the following steps:

[0131] (1) The organic matter-containing and salt-containing wastewater is introduced into the air flotation device 100 (a horizontal flow pressurized dissolved air flotation device 100) for air flotation at a pressure of 0.3 MPa. During the air flotation process, the pH value of the organic matter-containing and salt-containing wastewater is adjusted to 9 (the pH value is regulated using calcium hydroxide), and the TOC of the wastewater after air flotation is 1430 mg / L;

[0132] (2) The wastewater after flotation is introduced into the first sedimentation tank 201 for the first sedimentation treatment. During the first sedimentation process, a coagulant (poly aluminum sulfate), a coagulant aid (anionic polyacrylamide), a hard water softener (sodium hydroxide), a defluorinating agent (poly aluminum chloride), and an insecticide (sodium hypochlorite) are added; the total hardness in the wastewater after the first sedimentation treatment is <55 mg / L; Ca 2+ and Mg 2+ together are <18 mg / L;

[0133] (3) The wastewater after the first sedimentation treatment is introduced into the first-stage catalytic oxidation device 301 for the first-stage catalytic oxidation treatment; among them, the space velocity during the first-stage catalytic oxidation process is 0.5 h -1, the addition amount of H2O2 is 974 ppm (compared with the volume of the organic matter-containing and salt-containing wastewater); the particle size of the nano-foamed metal iron-based composite catalyst used in the primary catalytic oxidation treatment is 1 - 5 cm, the specific surface area is 13 m 2 / g, and the average pore diameter is 4 nm; the material of the nano-foamed metal iron-based composite catalyst contains 85 wt% of iron and 15 wt% of carbon; the TOC in the wastewater after the primary catalytic oxidation is 135 mg / L

[0134] (4) The wastewater after the primary catalytic oxidation treatment is introduced into the second sedimentation tank 202 for the second sedimentation treatment. During the treatment process, a coagulant (poly aluminum sulfate), a flocculation aid (anionic polyacrylamide), a hard water softener (sodium hydroxide), and a defluorination agent (poly aluminum chloride) are added;

[0135] (5) The wastewater after the second sedimentation treatment is subjected to the first filtration in the first filtration device 401. The first filtration device 401 used in the first filtration is the Huade Chuangye IAT high-speed precision filter; the turbidity of the inlet wastewater in the first filtration ranges from 198 NTU, and the turbidity of the treated wastewater is 5 NTU. The Ca 2+ in the wastewater after the first filtration is less than 30 ppm;

[0136] (6) The wastewater after the first filtration enters the secondary catalytic oxidation device 302 for secondary catalytic oxidation. The catalyst for the secondary catalytic oxidation is a nano-catalyst, specifically a nano nickel-iron alloy catalyst (the active component of the nano-catalyst is a ternary alloy of iron, nickel, and copper, the particle size of the active component is 20 - 30 nm, and the carrier of the nano-catalyst is activated carbon). The space velocity during the secondary catalytic oxidation process is 2 h -1 , the addition amount of H2O2 is 200 ppm (compared with the volume of the organic matter-containing and salt-containing wastewater); the TOC after the secondary catalytic oxidation is 28 mg / L;

[0137] (7) The wastewater after the secondary catalytic oxidation is introduced into the cation exchange resin device 500 for cation exchange; the cation exchange resin is a styrene-based sulfonic acid-type cation exchange resin D001; the wastewater after the cation exchange is subjected to the second filtration in the second filtration device 402, and the second filtration is an ultrafiltration membrane device of Hangzhou Kemao Company; the Ca+ concentration is reduced from 30 ppm to less than 1 ppm;

[0138] (8) The wastewater after the second filtration is introduced into the primary nanofiltration device 601 for primary nanofiltration to obtain primary nanofiltration product water and primary nanofiltration concentrate; among them, the membrane flux of the primary nanofiltration membrane is 15.8 L / m 2 h; the inlet pressure is 3.75 MPa; the water production recovery rate is 80%;

[0139] The water produced by the first-stage nanofiltration is fed into the second-stage nanofiltration device 602 for second-stage nanofiltration treatment to obtain a monovalent salt solution and second-stage nanofiltration concentrated water; among them, the membrane flux of the second-stage nanofiltration membrane is 15.5 L / m2h; the inlet pressure is 5.12 MPa; the water production recovery rate is 85%; after treatment by the first-stage nanofiltration device 601 and the second-stage nanofiltration device 602, the interception rate of TOC is 82.8%; among them, the second-stage nanofiltration concentrated water contains 39 g / L of NaCl; 148 g / L of Na2SO4; the second-stage nanofiltration concentrated water is returned to the first-stage nanofiltration device 601 for first-stage nanofiltration;

[0140] (9) The monovalent salt solution is fed into the reverse osmosis device 700 for treatment to obtain a monovalent salt concentrated solution; the monovalent salt concentrated solution is fed into the sodium chloride evaporation crystallization device 800 for crystallization to obtain crystalline sodium chloride; among them, the reverse osmosis device 700 uses ultra-high pressure reverse osmosis, the pressure is 8 - 12 Mpa, the inlet salt concentration is 68 g / L, the produced water salt concentration is 130 g / L of NaCl, and the membrane flux of the ultra-high pressure reverse osmosis is 41 - 50 L / m 2 h; the crystal nucleation rate during the evaporation crystallization process is 1 mm / h, the evaporation temperature is 100 °C, and NaCl is obtained;

[0141] The first-stage nanofiltration concentrated water is fed into the third-stage catalytic oxidation device 303 for third-stage catalytic oxidation and then into the sodium sulfate freeze crystallization device 900 for crystallization treatment to obtain mirabilite; among them, the catalyst for the third-stage catalytic oxidation is a nano-catalyst, specifically a nano nickel-iron alloy catalyst (the active component of the nano-catalyst is a ternary alloy of iron, nickel, and copper, the particle size of the active component is 20 - 30 nm, and the nano-catalyst carrier is activated carbon), the space velocity during the third-stage catalytic oxidation process is 2 h -1 , the addition amount of H2O2 is 200 ppm (compared with the volume of the organic matter-containing miscellaneous salt wastewater); the freeze crystallization temperature is 0 °C, and the freeze crystallization yield is 75%

[0142] Comparative Example 1

[0143] This comparative example is the same as the organic matter-containing miscellaneous salt wastewater in Example 4, and the treatment process is similar. The difference is that the pH is not controlled during the air flotation process; the TOC in the wastewater after air flotation is 1877 mg / L, which causes a greater pressure on the subsequent process. The TOC after the first-stage catalytic oxidation is 330 mg / L, and the space velocity during the second-stage catalytic oxidation process is 2 h -1 , the addition amount of H2O2 is 200 ppm (compared with the volume of the organic matter-containing miscellaneous salt wastewater); the TOC after the second-stage catalytic oxidation is 125 mg / L; the space velocity during the third-stage catalytic oxidation process is 2 h -1 , the addition amount of H2O2 is 200 ppm (compared with the volume of the organic matter-containing miscellaneous salt wastewater); the TOC after the third-stage catalytic oxidation is 96 mg / L; the higher organic matter content affects the membrane life and separation efficiency, and the freeze crystallization yield is reduced to 40%, and the purity of the evaporated sodium chloride and the purity of the crystalline mirabilite are reduced.

[0144] Comparative Example 2

[0145] This comparative example is the same as the organic matter miscellaneous salt wastewater in Example 4, and the treatment process is similar. The difference is that the catalyst used in the first-stage catalytic oxidation process is an iron alloy catalyst. The TOC after the first-stage catalytic oxidation is 938 mg / L, the space velocity in the second-stage catalytic oxidation process is 2 h -1 , the addition amount of H2O2 is 200 ppm (compared with the volume of the organic matter miscellaneous salt wastewater); the TOC after the second-stage catalytic oxidation is 550 mg / L; the space velocity in the third-stage catalytic oxidation process is 2 h -1 , the addition amount of H2O2 is 200 ppm (compared with the volume of the organic matter miscellaneous salt wastewater); the TOC after the third-stage catalytic oxidation is 235 mg / L; the higher organic matter content affects the service life and separation efficiency of the membrane, and the freezing crystallization yield is significantly reduced to 20%, and the purity of the evaporated sodium chloride and the purity of the crystallized mirabilite are significantly reduced.

[0146] Test Example

[0147] Ion chromatography was used to test the components of NaCl and mirabilite obtained in the examples and comparative examples, and the results are shown in Table 1 and Table 2.

[0148] Table 1

[0149]

[0150] The judgment is based on the first-class standard of refined industrial dry salt in "Industrial Salt" GB 5462-2015

[0151] Table 2

[0152]

[0153] The judgment is based on the commodity specification grades of traditional Chinese medicinal materials T / CACM 1021.220-2018

[0154] Obviously, the above examples are only examples clearly described and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for resource recovery of wastewater containing organic heterosalt, characterized in that, It includes the following steps: (1) Treat the wastewater containing organic salt impurities through air flotation, first precipitation, primary catalytic oxidation, second precipitation, first filtration, secondary catalytic oxidation, cation exchange, second filtration, and primary nanofiltration to obtain primary nanofiltration product water and primary nanofiltration concentrate; (2) Conduct secondary nanofiltration on the primary nanofiltration product water to obtain a monovalent salt solution and secondary nanofiltration concentrate. Conduct reverse osmosis on the monovalent salt solution to obtain a monovalent salt concentrated solution, and crystallize the latter monovalent salt concentrated solution to obtain crystalline sodium chloride; Return the secondary nanofiltration concentrate to the primary nanofiltration process for treatment; (3) Conduct tertiary catalytic oxidation on the primary nanofiltration concentrate and then conduct crystallization treatment to obtain crystalline mirabilite; Among them, control the pH value of the wastewater containing organic salt impurities during the air flotation process; when the wastewater containing organic salt impurities is acidic, lower the pH value of the wastewater containing organic salt impurities during the air flotation process; when the wastewater containing organic salt impurities is alkaline, raise the pH value of the wastewater containing organic salt impurities during the air flotation process; The catalyst for primary catalytic oxidation is selected from nano-foamed metal iron-based composite catalysts.

2. The method according to claim 1, characterized in that The concentration of the salt impurities in the wastewater containing organic salt impurities is 20 - 150 g / L, and the TOC content is 30 - 2000 mg / L. The wastewater containing organic salt impurities includes chloride ions, sulfate ions, sodium ions, calcium ions, and fluoride ions; Preferably, the wastewater containing organic salt impurities further includes at least one of carbonate ions, bicarbonate ions, and magnesium ions.

3. The method according to claim 1 or 2, characterized in that, Add a coagulant, a coagulant aid, a hard water softener, and a defluorinating agent during the first precipitation treatment and the second precipitation treatment.

4. The method according to any one of claims 1 to 3, characterized in that, The particle size of the nano-foamed metal iron-based composite catalyst is 1-5 cm, the specific surface area is 5-20 m 2 / g, the pore size distribution range is 10-100 nm, and the average pore size is 20-30 nm; the material of the nano-foamed metal iron-based composite catalyst contains 85-98 wt% of iron; Preferably, the material of the nano-foamed metal iron-based composite catalyst further includes carbon; Preferably, the space velocity of the primary catalytic oxidation process is 0.2 - 2.0 h -1 , and the addition amount of H2O2 is 50 - 2000 ppm; Preferably, the catalysts used for secondary catalytic oxidation and tertiary catalytic oxidation are nano-catalysts; Preferably, the active ingredient of the nano-catalyst is an iron-nickel-copper ternary alloy, the particle size of the active ingredient is 20 - 30 nm, and the carrier of the nano-catalyst is activated carbon; Preferably, the space velocity of the secondary catalytic oxidation and the tertiary catalytic oxidation is 0.2 - 2.0 h -1 , and the addition amount of H2O2 is 50 - 1000 ppm.

5. The method according to any one of claims 1-4, characterized in that, The filter medium in the first filtration is selected from modified polymer microporous suspended fiber filter cloth filter media particles; Preferably, the turbidity of the inlet wastewater for the first filtration ranges from 20 to 200 NTU, the turbidity of the treated wastewater is less than 5 NTU, and the Ca in the wastewater after the first filtration 2+ is less than 30 ppm.

6. The method according to any one of claims 1-5, characterized in that, The cation exchange resin used during the cation exchange process is selected from styrene-type sulfonic acid cation exchange resin D001 or acrylic acid-type weakly acidic cation exchange resin D113.

7. The method according to any one of claims 1-6, characterized in that The second filtration is selected from ultrafiltration devices.

8. The method according to any one of claims 1 to 7, characterized in that, The device of primary nanofiltration and the device of secondary nanofiltration are connected in series, and the membrane flux of the nanofiltration membrane modules of the device of primary nanofiltration and the device of secondary nanofiltration is 10-30 L / m 2 h, the inlet water pressure is 1.5-4 MPa, the water production recovery rate of primary nanofiltration is 60-90%, and the water production recovery rate of secondary nanofiltration is 80-96%.

9. The method according to any one of claims 1-8, characterized in that, The method for crystallizing the monovalent salt concentrated solution is selected from concentrated crystallization; Preferably, the crystallization method in step (3) is selected from freeze crystallization; Among them, the crystallization temperature is 0 - 5 °C.

10. A system for the resource recovery of wastewater containing organic heterosalt, characterized in that, It includes: A pretreatment device, including an air flotation device and a first sedimentation tank connected in sequence; A primary catalytic oxidation device, the water inlet of the primary catalytic oxidation device is connected to the water outlet of the first sedimentation tank; A second sedimentation tank, the water inlet of the second sedimentation tank is connected to the water outlet of the primary catalytic oxidation device; A first filtration device, the water inlet of the first filtration device is connected to the water outlet of the second sedimentation tank; A secondary catalytic oxidation device, the water inlet of the secondary catalytic oxidation device is connected to the water outlet of the first filtration device; A cation exchange resin device, the water inlet of the cation exchange resin device is connected to the water outlet of the secondary catalytic oxidation device; A second filtration device, the water inlet of the second filtration device is connected to the water outlet of the cation exchange resin device; The first-stage nanofiltration device, the water inlet of the first-stage nanofiltration device is connected to the water outlet of the second filtration device; the first-stage nanofiltration device further includes a first-stage nanofiltration product water outlet, a first-stage nanofiltration concentrated water outlet, and a second-stage nanofiltration concentrated water inlet; The second-stage nanofiltration device, the water inlet of the second-stage nanofiltration device is connected to the first-stage nanofiltration product water outlet; the second-stage nanofiltration device further includes a monovalent salt solution outlet and a second-stage nanofiltration concentrated water outlet; the second-stage nanofiltration concentrated water outlet is connected to the second-stage nanofiltration concentrated water inlet; The third-stage catalytic oxidation device, the water inlet of the third-stage catalytic oxidation device is connected to the first-stage nanofiltration concentrated water outlet; The reverse osmosis device, the water inlet of the reverse osmosis device is connected to the monovalent salt solution outlet of the second-stage nanofiltration device; The sodium chloride evaporation crystallization device, the water inlet of the sodium chloride evaporation crystallization device is connected to the water outlet of the reverse osmosis device; The sodium sulfate freeze crystallization device, the water inlet of the sodium sulfate freeze crystallization device is connected to the water outlet of the third-stage catalytic oxidation device.

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