A method for treating salty wastewater from coal chemical industry

Abstract

The present invention provides a method for treating coal chemical saline wastewater as a resource, the method comprising pretreatment, nanofiltration, membrane concentration, ozone photocatalysis and resin adsorption performed in sequence. The method for treating coal chemical saline wastewater as a resource provided by the present invention has high organic matter removal efficiency, low cost, simple process flow, no secondary pollution, stable operation, high degree of automation of operation control, and the final produced water meets the requirements of raw brine required by the ion membrane caustic soda process.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial wastewater treatment, and in particular relates to a method for treating salt-containing wastewater from coal chemical industry as a resource. Background Art

[0002] High-salt wastewater generated by the coal chemical industry, such as coking, coal pyrolysis, and coal gasification, contains organic pollutants such as phenols and heterocyclic compounds. The treatment and disposal costs are high, and the environmental problems are prominent, which seriously affects the sustainable development of the industry. The organic matter in high-salt wastewater is removed by advanced oxidation and anodic oxidation using a combination of resin adsorption, ozone-ultraviolet irradiation-hydrogen peroxide. The effluent is used as a raw material for the ion membrane caustic soda production process after fine filtration, but the process flow is relatively complicated. The organic matter in high-salt wastewater is degraded by a combination of ultraviolet irradiation, hydrogen peroxide, and persulfate, and the treatment effect is good. However, the addition of persulfate increases the salt content of the wastewater, and hydrogen peroxide is a hazardous chemical and its use is restricted.

[0003] CN112939321A discloses a zero-discharge treatment technology for wastewater from the steel industry, which mainly includes softening pretreatment, primary salt concentration, resin adsorption, membrane salt separation, sodium chloride membrane concentration and concentrated liquid removal of fluorine and silicon, adsorption regeneration liquid treatment, and evaporation crystallization. Through the coordination of the processes of each part, the concentrated water produced by the purified nanofiltration can be sent to the converter slag flushing or coking wastewater deep treatment concentration and salt extraction device in the steel enterprise. However, the treatment efficiency of this method is low, organic matter cannot be fully removed, and the problem of environmental pollution cannot be solved.

[0004] CN112456700A discloses a method for treating wastewater from urea-formaldehyde resin and phenol-formaldehyde resin production enterprises, which is mainly aimed at treating toxic organic wastewater containing methanol, formaldehyde, xylenol, etc. from urea-formaldehyde resin and phenol-formaldehyde resin production enterprises. Ozone is generated by an ozone generator with an intensity of 0.012kg / m 3 ~1.920kg / m 3 , mixed in a gas-liquid mixer and introduced into a reactor; high-frequency ultrasound is provided by an ultrasonic device, and the ultrasonic frequency is controlled to be 100-1000KHz; the catalyst is selected as anatase nano-grade TiO2, with a particle size of 3-30 nanometers, and is calcined on a molecular sieve by permeation adsorption; the stirring rate of the reactor is 90 rpm, and the ultraviolet light is provided by multiple high-pressure mercury lamps that emit a wavelength of 254nm; the pH value of the wastewater pool is adjusted to a weak alkaline value (6-9) by caustic soda flakes, slaked lime, etc. Under the synergistic effect of ozone ultrasound, ultraviolet light, and nano-titanium dioxide catalysis, toxic organic compounds in the waste liquid are oxidized and degraded, and finally decomposed into carbon dioxide and water. However, this method has a narrow scope of application and can only remove some organic matter, which cannot meet the actual needs of production practice.

[0005] CN111606518A discloses a comprehensive treatment method for coal coking wastewater, comprising the following steps: step one, pretreatment; step two, coagulation and sedimentation; step three, electrochemical-photocatalytic-ozone synergistic treatment; step four, porous ceramic medium filtration; the porous ceramic particles contain nano zero-valent iron generated in situ in the pores; step five, nanofiltration and reverse osmosis treatment: after passing through the nanofiltration system, it is treated by two-stage reverse osmosis to detect the water quality. The process steps of the present invention cooperate with each other, with compact layout, small footprint, low energy consumption, high treatment efficiency, electrochemical-photocatalytic-ozone synergy can completely remove organic pollutants such as cyanide and phenols in coking wastewater, and porous ceramic media can adsorb, replace and reduce heavy metal ions, and finally desalinate by nanofiltration and two-stage reverse osmosis system. Similarly, this method cannot fully remove organic matter, and the cost of using this method is high, which is not suitable for large-scale promotion.

[0006] The currently disclosed treatment methods for recycling coal chemical saline wastewater have certain defects. Therefore, it is very important to develop a process with low cost, simple process flow, safety, environmental protection and effective removal of organic matter from coal chemical saline wastewater. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a treatment method for the resource utilization of salt-containing wastewater from coal chemical industry. The treatment method provided by the present invention has high organic matter removal efficiency, low cost, simple process flow, no secondary pollution, stable operation and high degree of operation and control automation. The final produced water meets the requirements of raw brine required for the ion membrane caustic soda process.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for resource recovery of salt-containing wastewater from coal chemical industry, the method comprising pretreatment, nanofiltration, membrane concentration, ozone photocatalysis and resin adsorption performed in sequence.

[0010] The salt-containing wastewater from coal chemical industry in the present invention is first pretreated, and the obtained pretreated wastewater is subjected to nanofiltration to separate anions to obtain nanofiltration produced water, and the nanofiltration produced water is subjected to membrane concentration to enrich the salt in the nanofiltration produced water to obtain membrane concentrated concentrated water; the membrane concentrated concentrated water is subjected to ozone photocatalysis to reduce the organic matter content and then subjected to resin adsorption to further reduce the organic matter content, and the final produced water meets the requirements of raw brine required for the ion membrane caustic soda process.

[0011] The method for resource-based treatment of salt-containing wastewater from coal chemical industry provided by the present invention has high organic matter removal efficiency, low cost, simple process flow, no secondary pollution, stable operation and high degree of automation of operation control, and the final produced water meets the requirements of raw brine required for the ion membrane caustic soda process.

[0012] Preferably, the ozone photocatalysis includes a heterogeneous catalytic method consisting of ozone, ultraviolet light and a solid phase catalyst.

[0013] Preferably, the ozone is added by a dissolved air pump.

[0014] In the present invention, ozone is added into wastewater through a dissolved air pump to form micron bubbles or even nano bubbles, thereby increasing the ozone dissolution rate. Ozone forms active oxygen free radicals under the catalytic action of ultraviolet light and a solid-phase catalyst, which has a good removal effect on organic matter containing unsaturated bonds and small molecular organic matter of carboxylic acids, and can effectively reduce the content of total organic carbon, thereby achieving the purpose of reducing organic matter.

[0015] Preferably, the irradiation intensity of the ultraviolet light is 10-1000Mw / cm 2 , for example, it can be 10Mw / cm 2 、50Mw / cm 2 、100Mw / cm 2 、300Mw / cm 2 、500Mw / cm 2 、700Mw / cm 2 、900Mw / cm 2 or 1000Mw / cm 2 , but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, the wavelength of the ultraviolet light is 200-300nm, for example, it can be 200nm, 210nm, 220nm, 230nm, 240nm, 250nm, 260nm, 270nm, 280nm, 290nm or 300nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, the solid phase catalyst comprises TiO2 and / or doped TiO2.

[0018] Preferably, the doping elements in the doped TiO2 include any one of Ag, Co, N or S or a combination of at least two thereof, for example, a combination of Ag and Co, a combination of Co and N, a combination of N and S, a combination of Ag and N, or a combination of Ag, Co and N.

[0019] Preferably, the content of the doping element in the doped TiO2 is 0.1-5wt%, for example, it can be 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt% or 5wt%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, the pretreatment includes softening and hardness removal, ozone oxidation and ultrafiltration performed in sequence.

[0021] The softening and hardness removal methods of the present invention include but are not limited to lime-soda softening method and sodium hydroxide-soda softening method, which reduce the hardness of calcium, magnesium and other substances in wastewater. Ozone oxidation uses ozone as a strong oxidant to oxidize organic matter in wastewater and reduce the organic matter content in wastewater to TOC of 20-60 mg / L. The ultrafiltration process uses pressure as a driving force for membrane separation, mainly removing suspended matter and macromolecular organic matter in wastewater.

[0022] Preferably, nanofiltration product water is obtained after the nanofiltration, and the nanofiltration product water is subjected to membrane concentration.

[0023] The nanofiltration of the present invention separates impurity anions such as chloride ions and sulfate ions through a nanofiltration membrane to obtain nanofiltration produced water whose main anions are chloride ions. The nanofiltration produced water enters a membrane concentration unit, and the nanofiltration concentrated water is used for miscellaneous purposes.

[0024] Preferably, the separation efficiency of the nanofiltration is 96% to 99%, for example, it can be 96%, 96.5, 97%, 97.5, 98%, 98.5, or 99%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] The content of sodium chloride in the nanofiltration produced water of the present invention is 5000-25000 mg / L, and the content of impurity anions is 2-40 mg / L.

[0026] Preferably, the membrane concentration comprises reverse osmosis and electrodialysis performed sequentially.

[0027] Preferably, the electrodialysis comprises homogeneous ion membrane electrodialysis.

[0028] Preferably, after the membrane concentration, the salt content in the obtained membrane concentrated concentrated water is ≥18%.

[0029] Preferably, the resin used in the resin adsorption includes a macroporous adsorption resin.

[0030] The macroporous adsorption resin of the present invention is a type of polymer adsorption resin without exchange groups and having a macroporous structure, having a good network structure and a large specific surface area, and can selectively physically adsorb organic matter in an aqueous solution. The pore size of the macroporous adsorption resin is between 100nm and 1000nm.

[0031] Preferably, the resin adsorbs to a total organic carbon TOC of ≤5 mg / L, for example, 5 mg / L, 4 mg / L, 3 mg / L, 2 mg / L, 1 mg / L or 0.1 mg / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0032] Preferably, the macroporous adsorption resin comprises any one of XAD4 resin, XAD-2 resin, XAD-16N resin, HP20 resin, D101 resin, D201 resin, D301 resin, LX-5 adsorption resin, LX-160 resin or LX-60 resin, or a combination of at least two thereof, for example, it may be a combination of XAD4 resin and XAD-2 resin, a combination of XAD-2 resin and XAD-16N resin, a combination of XAD-16N resin and HP20 resin, a combination of HP20 resin and D101 resin, a combination of D101 resin and D201 resin, a combination of D201 resin and D301 resin, a combination of LX-5 adsorption resin and LX-160 resin, or a combination of XAD4 resin, XAD-2 resin and XAD-16N resin.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The organic matter removal efficiency is high, the cost is low, the process flow is simple, no secondary pollution is generated, the operation is stable and the operation control has a high degree of automation. The final produced water meets the requirements of the raw brine required for the ion membrane caustic soda process. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0036] The salt content of the coal chemical saline wastewater of the present invention is 10000-50000 mg / L, wherein the total content of calcium and magnesium ions is 200-1000 mg / L, the content of sodium chloride is 5000-25000 mg / L, the content of sodium sulfate is 5000-25000 mg / L, and the content of total organic carbon TOC is 50-150 mg / L.

[0037] Example 1

[0038] This embodiment provides a method for treating salt-containing wastewater from coal chemical industry as a resource, the method comprising:

[0039] The coal chemical wastewater is first subjected to pretreatment softening, hardness removal, ozone oxidation and ultrafiltration to obtain pretreated wastewater, and the total organic carbon TOC of the pretreated wastewater is 52 mg / L; the obtained pretreated wastewater is subjected to nanofiltration to separate chloride ions to obtain nanofiltration product water, and the sodium chloride content in the nanofiltration product water is 15000 mg / L and the sodium sulfate content is 3 mg / L; the nanofiltration product water is subjected to reverse osmosis and homogeneous ion membrane electrodialysis to enrich the salt in the nanofiltration product water to obtain membrane concentrated concentrated water, and the sodium chloride content of the membrane concentrated concentrated water is 195000 mg / L, the sodium sulfate content is 39 mg / L, and the total organic carbon TOC is 120 mg / L; the membrane concentrated concentrated water is subjected to ozone photocatalysis composed of ozone, ultraviolet light and a solid phase catalyst to reduce organic matter to a total organic carbon TOC of 37 mg / L, wherein ozone is added by a dissolved air pump and the irradiation intensity of the ultraviolet light is 100Mw / cm 2 The wavelength of ultraviolet light is 280nm, the solid phase catalyst uses 0.3wt% Ag-doped TiO2, and the produced water is adsorbed by XAD-4 resin to further reduce the organic matter content. The final produced water has a sodium chloride content of 196000mg / L, a sodium sulfate content of 38mg / L, and a total organic carbon TOC of 0.5mg / L.

[0040] Example 2

[0041] This embodiment provides a method for treating salt-containing wastewater from coal chemical industry as a resource, the method comprising:

[0042] The coal chemical wastewater is first subjected to pretreatment softening, hardness removal, ozone oxidation and ultrafiltration to obtain pretreated wastewater, and the total organic carbon TOC of the pretreated wastewater is 47 mg / L; the obtained pretreated wastewater is separated by nanofiltration to obtain nanofiltration product water, and the sodium chloride content in the nanofiltration product water is 17000 mg / L and the sodium sulfate content is 5 mg / L; the nanofiltration product water is subjected to reverse osmosis and homogeneous ion membrane electrodialysis to enrich the salt in the nanofiltration product water to obtain membrane concentrated concentrated water, and the sodium chloride content of the membrane concentrated concentrated water is 205000 mg / L, the sodium sulfate content is 60 mg / L, and the total organic carbon TOC is 100 mg / L; the membrane concentrated concentrated water is subjected to ozone photocatalysis composed of ozone, ultraviolet light and a solid phase catalyst to reduce organic matter to a total organic carbon TOC of 20 mg / L, wherein ozone is added by a dissolved air pump and the irradiation intensity of the ultraviolet light is 500Mw / cm 2 The wavelength of ultraviolet light is 200nm, the solid phase catalyst uses 0.1wt% N-doped TiO2, and the obtained produced water is adsorbed by XAD-16N resin to further reduce the organic matter content. The final produced water has a sodium chloride content of 207000mg / L, a sodium sulfate content of 60mg / L, and a total organic carbon TOC of 1mg / L.

[0043] Example 3

[0044] This embodiment provides a method for treating salt-containing wastewater from coal chemical industry as a resource, the method comprising:

[0045] The coal chemical wastewater is first subjected to pretreatment softening, hardness removal, ozone oxidation and ultrafiltration to obtain pretreated wastewater, and the total organic carbon TOC of the pretreated wastewater is 60 mg / L; the obtained pretreated wastewater is separated by nanofiltration to obtain nanofiltration product water, and the sodium chloride content in the nanofiltration product water is 12000 mg / L and the sodium sulfate content is 7 mg / L; the nanofiltration product water is subjected to reverse osmosis and homogeneous ion membrane electrodialysis to enrich the salt in the nanofiltration product water to obtain membrane concentrated concentrated water, and the sodium chloride content of the membrane concentrated concentrated water is 213000 mg / L, the sodium sulfate content is 125 mg / L, and the total organic carbon TOC is 200 mg / L; the membrane concentrated concentrated water is subjected to ozone photocatalysis composed of ozone, ultraviolet light and a solid phase catalyst to reduce organic matter to a total organic carbon TOC of 60 mg / L, wherein ozone is added by a dissolved air pump and the irradiation intensity of the ultraviolet light is 1000Mw / cm 2 The wavelength of ultraviolet light is 220nm, the solid phase catalyst uses 0.5wt% Co-doped TiO2, and the resulting produced water is adsorbed by HP20 resin to further reduce the organic matter content. The final produced water has a sodium chloride content of 216000mg / L, a sodium sulfate content of 126mg / L, and a total organic carbon TOC of 5mg / L.

[0046] Example 4

[0047] This embodiment provides a method for treating salt-containing wastewater from coal chemical industry as a resource, the method comprising:

[0048] The coal chemical wastewater is first subjected to pretreatment softening, hardness removal, ozone oxidation and ultrafiltration to obtain pretreated wastewater, and the total organic carbon TOC of the pretreated wastewater is 30 mg / L; the obtained pretreated wastewater is separated by nanofiltration to obtain nanofiltration product water, and the sodium chloride content in the nanofiltration product water is 19200 mg / L and the sodium sulfate content is 4 mg / L; the nanofiltration product water is subjected to reverse osmosis and homogeneous ion membrane electrodialysis to enrich the salt in the nanofiltration product water to obtain membrane concentrated concentrated water, and the sodium chloride content of the membrane concentrated concentrated water is 225000 mg / L, the sodium sulfate content is 50 mg / L, and the total organic carbon TOC is 80 mg / L; the membrane concentrated concentrated water is subjected to ozone photocatalysis composed of ozone, ultraviolet light and a solid phase catalyst to reduce organic matter to a total organic carbon TOC of 18 mg / L, wherein ozone is added by a dissolved air pump and the irradiation intensity of the ultraviolet light is 10Mw / cm 2 The wavelength of ultraviolet light is 300nm, the solid phase catalyst uses 5wt% S-doped TiO2, and the obtained produced water is adsorbed by D201 resin to further reduce the organic matter content. The final produced water has a sodium chloride content of 226000mg / L, a sodium sulfate content of 50mg / L, and a total organic carbon TOC of 1.3mg / L.

[0049] Example 5

[0050] This embodiment provides a method for treating salt-containing wastewater from coal chemical industry as a resource, the method comprising:

[0051] The coal chemical wastewater is first subjected to pretreatment softening, hardness removal, ozone oxidation and ultrafiltration to obtain pretreated wastewater, and the total organic carbon TOC of the pretreated wastewater is 39 mg / L; the obtained pretreated wastewater is separated by nanofiltration to obtain nanofiltration product water, and the sodium chloride content in the nanofiltration product water is 17500 mg / L and the sodium sulfate content is 2 mg / L; the nanofiltration product water is subjected to reverse osmosis and homogeneous ion membrane electrodialysis to enrich the salt in the nanofiltration product water to obtain membrane concentrated concentrated water, and the sodium chloride content of the membrane concentrated concentrated water is 192000 mg / L, the sodium sulfate content is 25 mg / L, and the total organic carbon TOC is 50 mg / L; the membrane concentrated concentrated water is subjected to ozone photocatalysis composed of ozone, ultraviolet light and solid phase catalyst to reduce organic matter to a total organic carbon TOC of 12 mg / L, wherein ozone is added by a dissolved air pump and the irradiation intensity of the ultraviolet light is 50Mw / cm 2 The wavelength of ultraviolet light is 250nm, TiO2 is used as solid phase catalyst, and the produced water is adsorbed by LX-160 resin to further reduce the organic matter content. The final produced water has a sodium chloride content of 194000mg / L, a sodium sulfate content of 24mg / L, and a total organic carbon TOC of 0.4mg / L.

[0052] Example 6

[0053] Except that ozone was added directly instead of by a dissolved air pump, the rest was the same as in Example 1. The final produced water had a sodium chloride content of 195500 mg / L, a sodium sulfate content of 39 mg / L, and a total organic carbon TOC of 7 mg / L.

[0054] Example 7

[0055] Except that the wavelength of the ultraviolet light is 150 nm, the rest is the same as Example 1. The sodium chloride content in the final produced water is 194500 mg / L, the sodium sulfate content is 40 mg / L, and the total organic carbon TOC is 4 mg / L.

[0056] Example 8

[0057] Except that the wavelength of the ultraviolet light is 350 nm, the rest is the same as Example 1. The sodium chloride content in the final produced water is 196500 mg / L, the sodium sulfate content is 42 mg / L, and the total organic carbon TOC is 3.7 mg / L.

[0058] Example 9

[0059] Except that ozone oxidation was not performed in the pretreatment, the rest was the same as in Example 1. The final produced water had a sodium chloride content of 195500 mg / L, a sodium sulfate content of 37 mg / L, and a total organic carbon TOC of 12 mg / L.

[0060] Example 10

[0061] Except for omitting the homogeneous ion membrane electrodialysis, the rest is the same as Example 1. The sodium chloride content in the final produced water is 105000 mg / L, the sodium sulfate content is 21 mg / L, and the total organic carbon TOC is 0.5 mg / L.

[0062] Comparative Example 1

[0063] This comparative example provides a method for treating salt-containing wastewater from coal chemical industry, which is the same as Example 1 except that ozone photocatalysis is omitted. The final produced water has a sodium chloride content of 197000 mg / L, a sodium sulfate content of 39 mg / L, and a total organic carbon TOC of 50 mg / L.

[0064] Comparative Example 2

[0065] This comparative example provides a method for treating salt-containing wastewater from coal chemical industry for resource utilization, which is the same as Example 1 except that the treatment method is adjusted to sequentially perform pretreatment, nanofiltration, membrane concentration, resin adsorption and ozone photocatalysis. The final produced water has a sodium chloride content of 195000 mg / L, a sodium sulfate content of 38 mg / L, and a total organic carbon TOC of 17 mg / L.

[0066] The treatment method for resource utilization of coal chemical saline wastewater in Examples 1-5 can efficiently remove suspended solids and organic matter in coal chemical wastewater and reduce the hardness of the wastewater. The final produced water meets the requirements of raw brine required for the ion membrane caustic soda process.

[0067] By comparing Example 1 with Example 6, it can be seen that the method of adding ozone in the present invention affects the removal efficiency of organic matter. When ozone is added directly, the efficiency of ozone photocatalysis becomes low, and the addition of ozone by a dissolved air pump helps to improve the efficiency of ozone photocatalysis. In the present invention, ozone is added to the salt-containing wastewater of coal chemical industry through a dissolved air pump to form micron bubbles or even nano bubbles, thereby improving the ozone dissolution rate.

[0068] By comparing Example 1 with Examples 7-8, it can be seen that the wavelength of ultraviolet light in the present invention will affect the removal efficiency of organic matter, and a high or low wavelength of ultraviolet light will lead to a low efficiency of ozone photocatalysis.

[0069] By comparing Example 1 with Example 9, it can be seen that the ozone oxidation in the pretreatment of the present invention affects the removal efficiency of organic matter. In the present invention, ozone oxidation is not performed during pretreatment, and the treatment efficiency of coal chemical saline wastewater becomes low. The preliminary treatment of organic matter by ozone oxidation helps to improve the treatment efficiency of coal chemical saline wastewater.

[0070] By comparing Example 1 with Example 10, it can be seen that the homogeneous ion membrane in the present invention affects the contents of sodium chloride and sodium sulfate in the final produced water. Without homogeneous ion membrane electrodialysis, the content of sodium chloride in the final produced water becomes lower and the content of sodium sulfate becomes higher.

[0071] By comparing Example 1 with Comparative Example 1, it can be seen that when ozone photocatalysis is not used in the treatment of salt-containing wastewater from coal chemical industry in the present invention, the TOC content of total organic matter in the final produced water increases, and the organic matter cannot be removed.

[0072] By comparing Example 1 with Comparative Example 2, it can be seen that after the order of resin adsorption and ozone photocatalysis is exchanged, the TOC content of total organic matter in the final produced water increases, and the organic matter removal efficiency becomes lower.

[0073] In summary, the method for treating coal chemical saline wastewater resource utilization provided by the present invention has high organic matter removal efficiency, low cost, simple process flow, no secondary pollution, stable operation and high degree of operation control automation.

[0074] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for treating salt-containing wastewater from coal chemical industry, characterized in that: The treatment method comprises pretreatment, nanofiltration, membrane concentration, ozone photocatalysis and resin adsorption performed in sequence; The pretreatment includes softening and hardness removal, ozone oxidation and ultrafiltration performed in sequence; The membrane concentration comprises reverse osmosis and electrodialysis performed sequentially; The electrodialysis includes homogeneous ion membrane electrodialysis; The ozone photocatalysis includes a heterogeneous catalytic method consisting of ozone, ultraviolet light and a solid phase catalyst; The irradiation intensity of the ultraviolet light is 10Mw / cm 2 -100Mw / cm 2 ; The wavelength of the ultraviolet light is 280nm-300nm; The solid phase catalyst includes doped TiO2; The doping element in the doped TiO2 includes S; The resin used in the resin adsorption includes a macroporous adsorption resin; The macroporous adsorption resin includes D201 resin.

2. The processing method according to claim 1, characterized in that: The ozone is added by using an air dissolving pump.

3. The processing method according to claim 1, characterized in that: The content of the doping element in the doped TiO2 is 0.1-5wt%.

4. The processing method according to claim 1, characterized in that: After the nanofiltration, nanofiltration product water is obtained, and the nanofiltration product water is subjected to membrane concentration.

5. The processing method according to claim 1, characterized in that: The separation efficiency of the nanofiltration is 96%-99%.

6. The processing method according to claim 1, characterized in that: After the membrane concentration, the salt content of the obtained membrane concentrated concentrated water is ≥18%.

7. The processing method according to claim 1, characterized in that: The resin adsorbs to a total organic carbon TOC of ≤5 mg / L.