A system and method for advanced treatment of printing and dyeing wastewater and application

Abstract

The application provides a printing and dyeing wastewater advanced treatment system and method and application, and relates to the technical field of water treatment. The system comprises an iron-carbon micro-electrolysis reactor, a first-stage pipeline processor and a second-stage pipeline processor. The inner wall of the first-stage pipeline processor is coated with nano manganese ferrite and / or internally arranged with activated carbon fiber cloth loaded with nano manganese ferrate. The second-stage pipeline processor is internally arranged with a strip-shaped biological carrier loaded with a microbial membrane. The system is suitable for the advanced treatment of industrial wastewater, especially the advanced treatment of printing and dyeing wastewater, and has the advantages of not occupying land, small investment, low cost and good adaptability.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, specifically to a deep treatment system, method, and application for dyeing and printing wastewater. Background Technology

[0002] The dyeing and printing industry generates a large amount of wastewater, characterized by large volume, high COD, high color, high toxicity, and poor biodegradability, making it difficult to treat. Wastewater treatment typically employs a three-stage approach: pretreatment, biological treatment, and advanced treatment. Pretreatment mainly uses physicochemical methods to remove fine fibers and floating / suspended solids from the wastewater and adjusts the pH value, preparing for subsequent biological and advanced treatment. Biological treatment primarily uses biological processes to degrade high concentrations of recalcitrant macromolecular organic matter. Advanced treatment methods mainly include advanced oxidation methods, such as photocatalytic oxidation, ozone oxidation, wet oxidation, electrochemical oxidation, Fenton oxidation, and persulfate (PDS) oxidation. There are also advanced treatment methods that combine advanced oxidation and biological treatment. Even so, in practice, many enterprises still fail to meet the requirements of the "Water Pollutant Discharge Standard for Textile Dyeing and Finishing Industry" (GB 4287-2012) (COD ≤ 60 mg / L), mainly due to excessive COD and color.

[0003] With the increasing stringency of national environmental standards, many older enterprises' production facilities are struggling to meet environmental requirements, yet they lack the space to build new treatment facilities, making it extremely difficult to comply with the new standards. Therefore, ensuring that wastewater meets standards upon reaching receiving water bodies under existing conditions is a pressing issue that the industry needs to address.

[0004] Typically, wastewater pipelines only serve a water transport function. However, some researchers have used these pipelines for wastewater pretreatment. Patent application number 2021107987508 discloses a pretreatment method for gas-water seal pipelines, using the pipelines for gas-water seal water detoxification pretreatment to improve the biodegradability of wastewater and reduce its impact on biological treatment systems. However, this method uses powdered activated carbon supported on manganese ferrite to prepare a catalyst, which is suspended in the water during use. On the one hand, the suspended powdered catalyst has high diffusion resistance and is prone to settling and accumulating in low-flow-rate sections (such as pipeline bends), resulting in relatively low ozone utilization. On the other hand, the catalyst is added at the beginning of the pipeline, recovered at the end, and then transported back to the beginning. This cyclical recovery process is not only very cumbersome, but also leads to simultaneous increases in energy consumption and losses. The active components of the catalyst are easily lost, resulting in decreased stability and deteriorated performance after regeneration. In addition, existing wastewater treatment plants are difficult to modify to adapt to magnetic recovery systems, and new facilities require additional land.

[0005] Currently, there is no literature on the use of wastewater pipelines for the advanced treatment of dyeing and printing wastewater. Summary of the Invention

[0006] The present invention aims to solve the technical problem that existing powdered activated carbon supported catalysts are difficult to use for deep treatment of dyeing and printing wastewater pipelines, as well as the problem that existing wastewater treatment facilities cannot make dyeing and printing wastewater meet the discharge standards, but there is no condition to build new deep treatment facilities.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a deep treatment system for dyeing and printing wastewater, comprising a wastewater classification and pretreatment unit and a two-stage pipeline treatment unit arranged sequentially.

[0009] The wastewater classification and pretreatment unit includes a wastewater collection pipe, a three-way diversion valve, an iron-carbon micro-electrolysis reactor, a multi-point acid addition device, a first pH adjustment device, and a deep cone thickener; the two-stage pipeline treatment unit includes a first-stage pipeline processor, a second-stage pipeline processor, an ozone microbubble injection device, a persulfate dosing device, and a second pH adjustment device.

[0010] A COD detector is installed on the wastewater collection pipe. The wastewater collection pipe is connected to the inlet of a three-way diverter valve. One outlet of the three-way diverter valve is connected to the iron-carbon micro-electrolysis reactor, and the other outlet is connected to the first-stage pipeline processor. Several acid outlets of the multi-point acid addition device extend into the iron-carbon micro-electrolysis reactor. The first pH adjustment device is set between the iron-carbon micro-electrolysis reactor and the deep cone thickener.

[0011] The outlet of the deep cone thickener is connected to the first-stage pipeline processor. The ozone outlet of the ozone microbubble injection device and the persulfate outlet of the persulfate dosing device are both connected to the inlet of the first-stage pipeline processor. The inner wall of the first-stage pipeline processor is coated with a nano-manganese ferrite coating and / or its interior is covered with activated carbon fiber cloth loaded with nano-manganese ferrite. The second pH adjustment device is located between the first-stage pipeline processor and the second-stage pipeline processor. The interior of the second-stage pipeline processor is covered with a strip-shaped biological carrier loaded with a microbial film.

[0012] Secondly, the present invention provides a method for deep treatment of dyeing and printing wastewater, comprising the following steps:

[0013] (1) Classification and treatment of dyeing and printing wastewater: The COD value of dyeing and printing wastewater is tested. If COD≤150mg / L, it is directly treated by two-stage pipeline treatment; if COD>150mg / L, it is first pretreated by iron-carbon micro-electrolysis and then treated by two-stage pipeline treatment.

[0014] (2) Iron-carbon micro-electrolysis pretreatment: After the wastewater enters the iron-carbon micro-electrolysis reactor, acid is added at multiple points to make the pH value in the iron-carbon micro-electrolysis reactor uniformly distributed and the pH is controlled at 3.0±0.2. The hydraulic retention time does not exceed 30 minutes and the COD of the effluent is less than 150mg / L. Alkali is added to adjust the pH value of the effluent from the iron-carbon micro-electrolysis reactor to 8-12, and then the flocs are separated by a deep cone thickener.

[0015] (3) Two-stage pipeline treatment: The effluent from the deep cone thickener is continuously treated through the first-stage pipeline processor and the second-stage pipeline processor before being discharged into the receiving water body. The inner wall of the first-stage pipeline processor is coated with nano-manganese ferrite and / or the interior is covered with activated carbon fiber cloth loaded with nano-manganese ferrite. The second-stage pipeline processor is covered with strip-shaped biological carriers loaded with microbial film. When the wastewater enters the inlet of the first-stage pipeline processor, microbubble ozone and sodium persulfate are injected.

[0016] Further, in step (3), the method of coating the inner wall of the first section of the pipeline processor with nano-manganese ferrite is as follows: nano-manganese ferrite and epoxy resin are mixed at a mass ratio of 3:7, and graphene oxide accounting for 0.5% of the total mass is added. The graphene oxide has a particle size of 1-5 μm and a purity of ≥99%. After being dispersed evenly, it is sprayed onto the inner wall of the first section of the pipeline processor to form a coating with a thickness of 60 μm.

[0017] Furthermore, the loading of nano-manganese ferrite on the inner wall of the first section of the pipeline processor is 100–500 g / m. 2 .

[0018] Further, in step (3), the method for loading nano-manganese ferrite onto activated carbon fiber cloth is as follows: take activated carbon fiber cloth with a width ≤ pipe diameter, mix silane coupling agent KH-550, water and ethanol in a mass ratio of 1:2:10, hydrolyze at 40℃ for 1h, immerse the activated carbon fiber cloth for 60min and then cure at 80℃ for 2h to obtain pretreated activated carbon fiber cloth; immerse the pretreated activated carbon fiber cloth in a mixture of Mn(NO3)2 and Fe(NO3)3 with a molar ratio of 2:1, load nano-manganese ferrite using a co-precipitation method, and dry at 120℃ to obtain; 1 to 3 activated carbon fiber cloths loaded with nano-manganese ferrite are arranged inside the first section of the pipe processor.

[0019] Furthermore, the loading of nano-manganese ferrite on the activated carbon fiber cloth is 350–500 g / m². 2 .

[0020] Furthermore, in step (3), the wastewater stays in the first and second pipeline processors for 15 to 30 minutes.

[0021] Furthermore, in step (3), ozone is released into the wastewater through a microporous disk with a pore size of 50-100 μm at the head of the first section of the pipeline processor. The initial concentration of ozone is 10-20 mg / L and the initial concentration of persulfate is 0.1-0.4 mmol / L.

[0022] Furthermore, in step (3), when the wastewater enters the first end of the second-stage pipeline processor, the concentrations of ozone and persulfate in the wastewater are less than 0.1 ppm.

[0023] Preferably, the persulfate is sodium persulfate.

[0024] Furthermore, in step (3), the strip-shaped biological carrier is made of corrugated polyester fiber with a width ≤ pipe diameter.

[0025] Furthermore, in step (3), the microbial film on the strip biological carrier is obtained by contact culture. Specifically, the effluent from the secondary sedimentation tank after biochemical treatment of dyeing and printing wastewater is brought into contact with the strip biological carrier, and microporous aeration is carried out for several days with dissolved oxygen of 4-6 mg / L. After the surface biofilm thickness reaches 200-300 μm, it is laid in the second-stage pipeline processor, with a laying quantity of 1-3 strips.

[0026] Furthermore, in step (3), the pH value of the treatment environment of the second pipeline processor is 7 to 8, and the pH value of the wastewater is adjusted by pH adjustment solution at the inlet of the second pipeline processor.

[0027] Thirdly, the present invention provides the application of the deep treatment system for dyeing and printing wastewater in the deep treatment of other industrial wastewater besides dyeing and printing wastewater, and determines the treatment time and oxidant dosage according to the corresponding direct discharge standards.

[0028] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0029] (1) Utilize existing pipeline facilities to expand their original water conveyance function into a multi-functional facility that integrates water conveyance and deep treatment without increasing the land area, making it easier for enterprises to use existing facilities to cope with the increase in drainage standards.

[0030] (2) The catalyst immobilization treatment greatly improves stability and lifespan, reduces catalyst loss rate, and solves the problem of easy sedimentation and loss of catalyst supported by suspended powder activated carbon. It does not require frequent recycling and regeneration, and the operation stability is significantly improved. Among them, the coating of the inner wall of the first section pipeline processor combines nano-manganese ferrite and graphene oxide with epoxy resin. The sheet structure of graphene oxide not only enhances the mechanical strength and erosion resistance of the coating, but its conductivity can also promote electron transfer and improve catalytic activity. After the activated carbon fiber cloth is pretreated with silane coupling agent, hydroxyl groups are formed on the surface, which are combined with nano-manganese ferrite through chemical bonds to improve the load strength.

[0031] (3) The two-stage pipeline treatment forms a synergistic chain of “oxidation and destruction - biochemical mineralization”, and the final effluent COD can be stably controlled below 60 mg / L and the color below 30. The first stage of catalytic oxidation can not only degrade organic matter, but also improve the biodegradability of wastewater and increase the dissolved oxygen concentration in the water, which is conducive to improving the decontamination efficiency of the second stage of pipeline biochemical treatment. The second stage of pipeline efficiently degrades the small molecule organic matter (such as carboxylic acids and alcohols) generated after the first stage of oxidation, and further degrades the residual trace oxidants (ozone and persulfate), avoiding them from entering the receiving water body and causing harm to aquatic organisms.

[0032] (4) A small amount of iron sludge generated by iron-carbon micro-electrolysis pretreatment can be recovered by a deep cone thickener and reused after treatment, realizing the resource utilization of solid waste and eliminating the problem of secondary pollution of sludge; reducing suspended matter entering the pipeline treatment and avoiding pipeline blockage, while the flocs adsorb some color substances, reducing the burden on subsequent deep treatment. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the advanced treatment system for dyeing and printing wastewater in Embodiment 1 of the present invention;

[0034] Figure 2 This is a process flow diagram of the deep treatment method for dyeing and printing wastewater in Embodiment 2 of the present invention;

[0035] Figure 3 These are SEM images of activated carbon fiber cloth before and after loading nano-manganese ferrite in Example 2 of the present invention, wherein a is the SEM image of activated carbon fiber cloth before loading nano-manganese ferrite; and b is the SEM image of activated carbon fiber cloth after loading nano-manganese ferrite.

[0036] Figure 4 The images show the implementation effects of the deep treatment methods for dyeing and printing wastewater in Examples 3 and 4. From left to right, they are the influent of Example 4, the pretreated effluent, the final effluent of Example 4, the influent of Example 3, and the final effluent of Example 3.

[0037] Figure labels: 1-Wastewater collection pipe, 2-COD detector, 3-Three-way diverter valve, 4-Iron-carbon micro-electrolysis reactor, 5-Multi-point acid addition device, 6-First pH adjustment device, 7-Deep cone thickener, 8-First-stage pipeline processor, 801-Nano manganese ferrite coating, 802-Activated carbon fiber cloth loaded with nano manganese ferrite, 9-Second-stage pipeline processor, 901-Strip biological carrier loaded with microbial film, 10-Ozone microbubble injection device, 11-Persulfate dosing device, 12-Second pH adjustment device. Detailed Implementation

[0038] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments.

[0039] Example 1

[0040] like Figure 1 As shown, this embodiment of a deep treatment system for dyeing and printing wastewater includes a wastewater classification and pretreatment unit and a two-stage pipeline treatment unit arranged sequentially. The wastewater classification and pretreatment unit includes a wastewater collection pipe 1, a three-way diversion valve 3, an iron-carbon micro-electrolysis reactor 4, a multi-point acid addition device 5, a first pH adjustment device 6, and a deep cone thickener 7. The two-stage pipeline treatment unit includes a first-stage pipeline processor 8, a second-stage pipeline processor 9, an ozone microbubble injection device 10, a persulfate dosing device 11, and a second pH adjustment device 12. A COD detector 2 is installed on the wastewater collection pipe 1. The wastewater collection pipe 1 is connected to the inlet of the three-way diversion valve 3. One outlet of the three-way diversion valve 3 is connected to the iron-carbon micro-electrolysis reactor 4, and the other outlet is connected to the first-stage pipeline processor. 8. Several acid outlets of the multi-point acid addition device 5 extend into the iron-carbon micro-electrolysis reactor 4. The first pH adjustment device 6 is located between the iron-carbon micro-electrolysis reactor 4 and the deep cone thickener 7. The outlet of the deep cone thickener 7 is connected to the first-stage pipeline processor 8. The ozone outlet of the ozone microbubble injection device 10 and the persulfate outlet of the persulfate addition device 11 are both connected to the inlet of the first-stage pipeline processor 8. The inner wall of the first-stage pipeline processor 8 is coated with a nano-manganese ferrite coating 801 and / or its interior is provided with activated carbon fiber cloth 802 loaded with nano-manganese ferrite. The second pH adjustment device 12 is located between the first-stage pipeline processor 8 and the second-stage pipeline processor 9. The interior of the second-stage pipeline processor 9 is provided with a strip-shaped biological carrier 901 loaded with a microbial membrane.

[0041] In this embodiment, the COD detector 2 is used to detect the COD value of the influent. When the detected COD is ≤150mg / L, the water flow is introduced into the two-stage pipeline treatment unit through the three-way diversion valve 3. When the detected COD is >150mg / L, the water flow is introduced into the iron-carbon micro-electrolysis reactor 4 through the three-way diversion valve 3. The deep cone thickener 7 is used to separate the flocs generated by the iron-carbon micro-electrolysis. The first pH adjustment device 6 is used to adjust the pH value of the effluent at the outlet of the iron-carbon micro-electrolysis reactor 4 to 8-12. The second pH adjustment device 12 is used to adjust the pH value of the effluent at the outlet of the first-stage pipeline processor 8 to 7-8.

[0042] Example 2

[0043] like Figure 2 As shown in this embodiment, a method for deep treatment of dyeing and printing wastewater includes the following steps:

[0044] (1) Classification and treatment of dyeing and printing wastewater: The COD value of dyeing and printing wastewater is tested. If COD≤150mg / L, it is directly treated by two-stage pipeline treatment; if COD>150mg / L, it is first pretreated by iron-carbon micro-electrolysis and then treated by two-stage pipeline treatment.

[0045] (2) Iron-carbon micro-electrolysis pretreatment: After the wastewater enters the iron-carbon micro-electrolysis reactor, acid is added at multiple points to make the pH value in the iron-carbon micro-electrolysis reactor uniformly distributed and the pH is controlled at 3.0±0.2. The hydraulic retention time does not exceed 30 minutes and the COD of the effluent is less than 150mg / L. Alkali is added to adjust the pH value of the effluent from the iron-carbon micro-electrolysis reactor to 8-12, and then the flocs are separated by a deep cone thickener.

[0046] (3) Two-stage pipeline treatment: The effluent from the deep cone thickener is continuously treated through the first-stage pipeline processor and the second-stage pipeline processor before being discharged into the receiving water body. The inner wall of the first-stage pipeline processor is coated with nano-manganese ferrite and / or the interior is covered with activated carbon fiber cloth loaded with nano-manganese ferrite. The second-stage pipeline processor is covered with strip-shaped biological carriers loaded with microbial film. When the wastewater enters the inlet of the first-stage pipeline processor, microbubble ozone and sodium persulfate are injected.

[0047] Specifically, in step (3), the method for coating the inner wall of the first section of the pipeline processor with nano-manganese ferrite is as follows: nano-manganese ferrite is mixed with epoxy resin, and graphene oxide is added. The graphene oxide has a particle size of 1-5 μm and a purity of ≥99%. After being evenly dispersed, it is sprayed onto the inner wall of the first section of the pipeline processor to form a coating with a thickness of 60 μm. The loading of nano-manganese ferrite on the inner wall of the first section of the pipeline processor is 100-500 g / m. 2 .

[0048] To optimize the performance of the coating on the inner wall of the first-stage pipeline processor, the effects of different mass ratios of nano-manganese ferrite (MnFe2O4) and epoxy resin (EP), as well as different amounts of graphene oxide (GO) added, on the coating performance and catalytic effect were tested. The evaluation indicators included the coating adhesion (characterizing the bonding strength), COD removal rate (characterizing catalytic activity), and catalyst shedding rate (characterizing stability). The test results are shown in Table 1.

[0049] Table 1. Comparison of Performance of Different Coating Ratios on the Inner Wall of the First-Section Pipe Processor

[0050] Group <![CDATA[MnFe2O4: EP mass ratio]]> GO addition amount (wt%) Adhesion (MPa) COD removal rate (%) Catalyst shedding rate (mg / L·h) 1 2 : 8 0.5 10.5 58.2 0.8 2 3 : 7 0 9.8 65.1 1.5 3 3 : 7 0.5 11.2 72.5 0.3 4 3 : 7 1.0 11.5 70.8 0.4 5 4 : 6 0.5 8.2 73.8 3.1

[0051] As shown in Table 1, group 3 (MnFe2O4 : EP = 3:7, GO addition 0.5%) achieved the best balance among adhesion, COD removal rate and stability, and is therefore the optimal ratio.

[0052] Graphene oxide not only serves as a reinforcing phase to enhance mechanical strength, but also forms a "microcapsule-like" repair system with epoxy resin through its unique two-dimensional sheet structure. When the coating develops microcracks due to water erosion or localized friction, the graphene oxide sheets can spontaneously migrate and fill the cracks through π-π bond interactions. Simultaneously, the hydroxyl groups on its surface can re-crosslink with unreacted functional groups in the epoxy resin, achieving dynamic self-healing of the coating. Pull-out tests show that the epoxy resin-graphene oxide composite coating achieves an adhesion of 11.2 MPa on a Q235 carbon steel substrate.

[0053] Specifically, in step (3), the method for loading nano-manganese ferrite onto activated carbon fiber cloth is as follows: Take activated carbon fiber cloth with a width ≤ pipe diameter, mix silane coupling agent KH-550, water, and ethanol in a mass ratio of 1:2:10, hydrolyze at 40℃ for 1 hour, immerse the activated carbon fiber cloth for 60 minutes, and then cure at 80℃ for 2 hours to obtain pretreated activated carbon fiber cloth; immerse the pretreated activated carbon fiber cloth in a mixture of Mn(NO3)2 and Fe(NO3)3, load nano-manganese ferrite using a co-precipitation method, and dry at 120℃ to obtain the final product; arrange 1 to 3 activated carbon fiber cloths loaded with nano-manganese ferrite inside the first section of the pipe processor; the loading amount of nano-manganese ferrite on the activated carbon fiber cloth is 350 to 500 g / m 2 .

[0054] When nano-manganese ferrite is loaded onto activated carbon fiber cloth using a co-precipitation method, the manganese (Mn) content in the precursor solution... 2+ ) and iron (Fe 3+ The molar ratio of α to β is a key factor affecting the final crystal phase structure and catalytic activity of the catalyst. We tested the effect of different molar ratios on catalytic performance, and the evaluation indicators included persulfate (PDS) decomposition rate, hydroxyl radical (•OH) generation (using benzoic acid as a probe molecule), and COD removal rate. The test results are shown in Table 2.

[0055] Table 2 Different Mn 2+ / Fe 3+ Comparison table of molar ratio catalytic performance

[0056] Group <![CDATA[Mn 2+ Fe 3+ molar ratio PDS decomposition rate (%) • OH- production (au) COD removal rate (%) 1 1 : 2 85.4 85 68.7 2 1 : 1 91.6 92 71.5 3 2 : 1 98.2 99 75.3 4 3 : 1 96.5 98 74.1

[0057] As shown in Table 2, when Mn 2+ Fe 3+ When the molar ratio is 2:1, the prepared nano-manganese ferrite catalyst exhibits the best performance in terms of activating persulfate decomposition, generating free radicals, and ultimately removing COD. Therefore, this molar ratio is the optimal choice.

[0058] The -Si-OH groups formed after the hydrolysis of KH-550 undergo a condensation reaction with the hydroxyl groups on the surface of the activated carbon fiber cloth, generating -Si-OC- covalent bonds with a bond energy of 452 kJ / mol. This chemical bonding significantly improves the load-bearing strength of the nano-manganese ferrite. The microporous structure of the activated carbon fiber cloth (pore size 5-20 nm) and the nano-manganese ferrite particles (particle size 20-50 nm) form a "mortise and tenon effect," which can disperse more than 80% of the stress under shear force, avoiding local failure. Using the monofilament pull-out method, the interfacial shear strength between the loaded activated carbon fiber cloth and the nano-manganese ferrite can reach 14.5 MPa.

[0059] Specifically, in step (3), the wastewater stays in the first and second pipeline processors for 15 to 30 minutes; ozone is released into the wastewater through a microporous disk with a pore size of 50-100 μm at the head of the first pipeline processor, with an initial ozone concentration of 10 to 20 mg / L and an initial persulfate concentration of 0.1 to 0.4 mmol / L; when the wastewater enters the head of the second pipeline processor, the concentrations of ozone and persulfate in the wastewater are less than 0.1 ppm.

[0060] Preferably, the persulfate is sodium persulfate.

[0061] Specifically, in step (3), the strip-shaped biological carrier is made of corrugated polyester fiber with a width ≤ pipe diameter; the microbial film on the strip-shaped biological carrier is obtained by contact culture, specifically by contacting the effluent from the secondary sedimentation tank after biochemical treatment of dyeing and printing wastewater with the strip-shaped biological carrier, aerating it through micropores for several days with dissolved oxygen of 4-6 mg / L, so that the surface biofilm thickness reaches 200-300 μm, and then laying it in the second section of the pipe processor, with a laying quantity of 1-3 strips.

[0062] Specifically, in step (3), the pH value of the treatment environment of the second pipeline processor is 7 to 8, and the pH value of the wastewater is adjusted by pH adjustment solution at the inlet of the second pipeline processor.

[0063] Example 3

[0064] The effluent quality of the dyeing and printing wastewater treatment plant is as follows: COD content 140.27 mg / L, color 200; the wastewater undergoes a two-stage pipeline treatment. The first stage pipeline processor contains two activated fiber cloths loaded with nano-manganese ferrite, the width of which is 85% of the pipe diameter, and the nano-manganese ferrite loading is 400 g / m². 2 The nano-manganese ferrite loading on the pipe wall is 250 g / m. 2The pH of the wastewater was adjusted to 10 using sodium hydroxide solution. Two strip-shaped biofilm carriers, made of corrugated polyester fiber, were installed in the second-stage pipeline processor. The width of the biofilm carriers was 85% of the pipe diameter, and the biofilm thickness was 250 μm. Hydrochloric acid solution was added at the beginning of the second-stage pipeline processor to adjust the pH of the wastewater to 7.5. The residence times of the wastewater in the first and second-stage pipeline processors were 25 min and 30 min, respectively. Ozone and sodium persulfate were added at the beginning of the first-stage pipeline processor. The initial ozone concentration was 20 mg / L, and the persulfate concentration was 0.2 mmol / L. At the end of the first-stage pipeline processor, the ozone and persulfate concentrations were 0.08 ppm and 0.07 ppm, respectively. After two-stage pipeline treatment, the effluent COD was 55.65 mg / L, and the color was 28, meeting the direct discharge standards and being directly discharged into the receiving water body.

[0065] Example 4

[0066] The effluent quality of the dyeing and printing wastewater treatment plant is as follows: COD content 350.60 mg / L, color 310. The wastewater first undergoes short-term iron-carbon micro-electrolysis treatment. The iron-carbon micro-electrolysis reactor is filled with commercial iron-carbon micro-electrolysis packing material, and hydrochloric acid solution is added at multiple points to ensure a uniform pH distribution within the reactor, with a pH value of 3 and a hydraulic retention time of 25 min. The effluent COD content is 148.80 mg / L, and the color is 3. Sodium hydroxide is added to adjust the pH value of the wastewater to 12, and then the effluent undergoes floc separation using a deep cone thickener. The effluent then undergoes two-stage pipeline treatment. The first stage pipeline processor contains three activated fiber cloths loaded with nano-manganese ferrite, one with a width of 90% of the pipe diameter and the other two with a width of 75% of the pipe diameter. The nano-manganese ferrite loading is 370 g / m³. 2 The nano-manganese ferrite loading on the pipe wall is 150 g / m. 2 The second-stage pipeline processor contains three strip-shaped biofilm carriers made of corrugated polyester fiber. One strip is 90% the pipe diameter in width, and the other two are 75% the pipe diameter. The biofilm thickness is 270 μm. The wastewater retention times in the first and second-stage pipeline processors are 35 min and 25 min, respectively. Ozone and sodium persulfate are added at the beginning of the first-stage pipeline processor. The initial ozone concentration is 20 mg / L, and the persulfate concentration is 0.15 mmol / L. At the end of the first-stage pipeline processor, the ozone and persulfate concentrations are 0.07 ppm and 0.05 ppm, respectively. At the beginning of the second-stage pipeline processor, hydrochloric acid solution is added to adjust the pH of the wastewater to 7.4. After pipeline treatment, the effluent COD content is 48.61 mg / L, and the color is 2, meeting the direct discharge standard and being directly discharged into the receiving water body.

[0067] Example 5

[0068] The effluent quality of the dyeing and printing wastewater treatment plant is as follows: COD content 130.2 mg / L, color 198; the wastewater undergoes a two-stage pipeline treatment. The first stage pipeline processor contains two active fiber cloths loaded with nano-manganese ferrite, with a width of 85% of the pipe diameter and a nano-manganese ferrite loading of 480 g / m². 2 The nano-manganese ferrite loading on the tube wall is 350 g / m³. 2 The pH of the wastewater was adjusted to 9.5 using sodium hydroxide solution. Two strip-shaped biofilm carriers, made of corrugated polyester fiber, were installed in the second-stage pipeline processor. The width of the biofilm carriers was 85% of the pipe diameter, and the biofilm thickness was 290 μm. Hydrochloric acid solution was added to the beginning of the second-stage pipeline processor to adjust the pH of the wastewater to 7.8. The residence times of the wastewater in the first and second-stage pipeline processors were 35 min and 25 min, respectively. Ozone and sodium persulfate were added to the beginning of the first-stage pipeline processor. The initial ozone concentration was 15 mg / L, and the persulfate concentration was 0.35 mmol / L. The ozone and persulfate concentrations at the end of the first-stage pipeline processor were 0.07 ppm and 0.06 ppm, respectively. After pipeline treatment, the effluent COD was 45.82 mg / L, and the color was 26. Hydrochloric acid solution was added to the beginning of the second-stage pipeline processor to adjust the pH to 7.6. The water quality met the direct discharge standards and was directly discharged into the receiving water body.

[0069] The above are merely embodiments of the present invention, described in a relatively specific and detailed manner, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A deep treatment system for dyeing and printing wastewater, characterized in that, It includes a wastewater classification and pretreatment unit and a two-stage pipeline treatment unit arranged sequentially; The wastewater classification and pretreatment unit includes a wastewater collection pipe, a three-way diversion valve, an iron-carbon micro-electrolysis reactor, a multi-point acid addition device, a first pH adjustment device, and a deep cone thickener; the two-stage pipeline treatment unit includes a first-stage pipeline processor, a second-stage pipeline processor, an ozone microbubble injection device, a persulfate dosing device, and a second pH adjustment device. A COD detector is installed on the wastewater collection pipe. The wastewater collection pipe is connected to the inlet of a three-way diverter valve. One outlet of the three-way diverter valve is connected to the iron-carbon micro-electrolysis reactor, and the other outlet is connected to the first-stage pipeline processor. Several acid outlets of the multi-point acid addition device extend into the iron-carbon micro-electrolysis reactor. The first pH adjustment device is set between the iron-carbon micro-electrolysis reactor and the deep cone thickener. The outlet of the deep cone thickener is connected to the first-stage pipeline processor. The ozone outlet of the ozone microbubble injection device and the persulfate outlet of the persulfate dosing device are both connected to the inlet of the first-stage pipeline processor. The inner wall of the first-stage pipeline processor is coated with a nano-manganese ferrite coating and / or its interior is covered with activated carbon fiber cloth loaded with nano-manganese ferrite. The second pH adjustment device is located between the first-stage pipeline processor and the second-stage pipeline processor. The interior of the second-stage pipeline processor is covered with a strip-shaped biological carrier loaded with a microbial film. The method for coating the inner wall of the first-stage pipeline processor with nano-manganese ferrite is as follows: nano-manganese ferrite is mixed with epoxy resin at a mass ratio of 3:7, and 0.5% graphene oxide is added according to the total mass. The graphene oxide has a particle size of 1-10 μm and a purity of ≥99%. After being evenly dispersed, it is sprayed onto the inner wall of the first-stage pipeline processor to form a coating with a thickness of 50-80 μm and a loading of 100-500 g / m. 2 ; The method for loading nano-manganese ferrite onto activated carbon fiber cloth is as follows: Take activated carbon fiber cloth with a width ≤ pipe diameter, mix silane coupling agent KH-550, water, and ethanol at a mass ratio of 1:2:10, hydrolyze at 40℃ for 1 hour, immerse the activated carbon fiber cloth for 60 minutes, and then cure at 80℃ for 2 hours to obtain pretreated activated carbon fiber cloth; immerse the pretreated activated carbon fiber cloth in a mixture of Mn(NO3)2 and Fe(NO3)3 with a molar ratio of 2:1, load nano-manganese ferrite using a co-precipitation method, and dry at 120℃ with a loading amount of 350~500g / m²; arrange 1~3 activated carbon fiber cloths loaded with nano-manganese ferrite inside the first section of the pipe processor.

2. The application of the advanced treatment system for dyeing and printing wastewater as described in claim 1 in the advanced treatment of other industrial wastewater besides dyeing and printing wastewater.

3. A method for deep treatment of dyeing and printing wastewater, characterized in that, Includes the following steps: (1) Classification and treatment of dyeing and printing wastewater: The COD value of dyeing and printing wastewater is tested. If COD≤150mg / L, it is directly treated by two-stage pipeline treatment; if COD>150mg / L, it is first pretreated by iron-carbon micro-electrolysis and then treated by two-stage pipeline treatment. (2) Iron-carbon micro-electrolysis pretreatment: After the wastewater enters the iron-carbon micro-electrolysis reactor, acid is added at multiple points to make the pH value in the iron-carbon micro-electrolysis reactor uniformly distributed and the pH is controlled at 3.0±0.

2. The hydraulic retention time does not exceed 30 minutes and the COD of the effluent is less than 150mg / L. Alkali is added to adjust the pH value of the effluent from the iron-carbon micro-electrolysis reactor to 8-12, and then the flocs are separated by a deep cone thickener. (3) Two-stage pipeline treatment: The effluent from the deep cone thickener is continuously treated through the first-stage pipeline processor and the second-stage pipeline processor before being discharged into the receiving water body. The inner wall of the first-stage pipeline processor is coated with nano-manganese ferrite and / or the interior is covered with activated carbon fiber cloth loaded with nano-manganese ferrite. The second-stage pipeline processor is covered with strip-shaped biological carriers loaded with microbial films. When the wastewater enters the inlet of the first-stage pipeline processor, microbubble ozone and sodium persulfate are injected. In step (3), the method for coating the inner wall of the first section of the pipeline processor with nano-manganese ferrite is as follows: nano-manganese ferrite and epoxy resin are mixed at a mass ratio of 3:7, and 0.5% of graphene oxide is added according to the total mass. The graphene oxide has a particle size of 1-10 μm and a purity of ≥99%. After being evenly dispersed, it is sprayed onto the inner wall of the first section of the pipeline processor to form a coating with a thickness of 50-80 μm and a loading of 100-500 g / m. 2 ; In step (3), the method for loading nano-manganese ferrite onto activated carbon fiber cloth is as follows: Take activated carbon fiber cloth with a width ≤ pipe diameter, mix silane coupling agent KH-550, water and ethanol in a mass ratio of 1:2:10, hydrolyze at 40℃ for 1h, immerse the activated carbon fiber cloth for 60min and then cure at 80℃ for 2h to obtain pretreated activated carbon fiber cloth; immerse the pretreated activated carbon fiber cloth in a mixture of Mn(NO3)2 and Fe(NO3)3 with a molar ratio of 2:1, load nano-manganese ferrite using a co-precipitation method, dry at 120℃, and the loading amount is 350~500g / m²; 1~3 activated carbon fiber cloths loaded with nano-manganese ferrite are arranged inside the first section of the pipe processor.

4. The method for deep treatment of dyeing and printing wastewater according to claim 3, characterized in that: In step (3), the wastewater stays in the first and second pipeline processors for 15 to 30 minutes. Ozone is released into the wastewater through a microporous disk with a pore size of 50-100 μm at the head of the first pipeline processor. The initial concentration of ozone is 10 to 20 mg / L and the initial concentration of persulfate is 0.1 to 0.4 mmol / L.

5. The method for deep treatment of dyeing and printing wastewater according to claim 3, characterized in that: In step (3), when the wastewater enters the first end of the second-stage pipeline processor, the concentrations of ozone and persulfate in the wastewater are less than 0.1 ppm.

6. The method for deep treatment of dyeing and printing wastewater according to claim 3, characterized in that: In step (3), the strip-shaped biological carrier is made of corrugated polyester fiber with a width ≤ pipe diameter. The microbial film on the strip-shaped biological carrier is obtained by contact culture. Specifically, the effluent from the secondary sedimentation tank after biochemical treatment of dyeing and printing wastewater is brought into contact with the strip-shaped biological carrier, and microporous aeration is carried out for several days with dissolved oxygen of 4-6 mg / L. After the surface biofilm thickness reaches 200-300 μm, it is laid in the second section of the pipe processor, with a number of 1-3 strips.

7. The method for deep treatment of dyeing and printing wastewater according to claim 3, characterized in that: In step (3), the pH value of the treatment environment of the second pipeline processor is 7 to 8, and the pH value of the wastewater is adjusted by pH adjustment solution at the inlet of the second pipeline processor.

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