Wastewater treatment process equipment for bamboo wood pulp and treatment process of wastewater treatment process equipment

Abstract

The invention discloses wastewater treatment process equipment for bamboo wood pulp and a treatment process of the wastewater treatment process equipment, relates to the technical field of wastewater treatment, and solves the defects existing in existing biological treatment of bamboo wood pulp wastewater, namely the technical problems that the wastewater cannot be effectively degraded and economization is difficult to realize due to the fact that microorganisms are inactivated in an alkaline environment. A brand-new membrane process equipment method is adopted, a black liquor tank is included, a stock solution pipe is arranged at the input end of the black liquor tank, the output end of the black liquor tank is connected with a dosing treatment structure, and the output end of the dosing treatment structure is connected with a pretreatment structure; according to the invention, suspended solids, large-particle impurities, organic pollutants and chemical pollutants in wastewater can be effectively removed through a multi-stage treatment structure, and efficient wastewater treatment is realized; meanwhile, fresh water filtered by the membrane is recycled, so that the environment-friendly targets of zero emission of bamboo wood pulp wastewater treatment and resource recycling are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and specifically to a wastewater treatment process equipment and its treatment process for bamboo pulp wastewater. Background Art

[0002] The technical field related to the present invention is specifically a bamboo pulp wastewater treatment process equipment. Compared with the traditional bamboo pulp wastewater treatment method, it has made significant progress in terms of resource recycling and reuse, and achieving zero discharge and improving environmental protection capabilities through the recycled use of treated water in the water cycle process. The existing bamboo pulp wastewater is treated by biological methods, that is, anaerobic-aerobic and other biological treatment processes are used to further degrade the organic matter in the wastewater by the metabolic action of microorganisms, reducing the chemical oxygen demand (COD) and biochemical oxygen demand (BOD). Since bamboo pulp wastewater is alkaline wastewater with a pH value of 9-10 or even higher, biological bacteria cannot survive, and a large amount of acid needs to be consumed to adjust the pH value to neutral or slightly acidic to adapt to biodegradation. At the same time, the salts generated due to acid-base neutralization will also inhibit the activity of the organisms, having disadvantages such as poor stability, low efficiency, long treatment cycle (4-5 days), and high cost. Therefore, the existing biological method for treating bamboo wastewater has technical problems such as difficulty in meeting high-efficiency requirements and high operating costs, making it difficult to achieve economicization.

[0003] By efficiently treating pollutants and recovering valuable resources, wastewater treatment equipment significantly reduces resource waste and environmental protection costs, while promoting the development of circular economy.

[0004] The treatment of bamboo pulp wastewater is not only of great significance to environmental protection, but also demonstrates economic and social value. Efficient wastewater treatment reduces the direct discharge of industrial pollutants, helps to improve the water ecological environment, and reduces the damage to the water ecosystem. At the same time, these processes enhance the enterprise's energy conservation and emission reduction capabilities, realize the resource utilization of wastewater, such as reusing intermediate water and reusing chemical raw materials, thereby reducing production costs and improving operating efficiency. In addition, modern wastewater treatment meets the requirements of national and local environmental protection regulations, avoids legal and economic risks caused by excessive emissions, and is more conducive to the improvement of the enterprise image, highlighting the social responsibility of environmentally friendly manufacturing. Generally speaking, the special equipment and technology for bamboo pulp wastewater are important supports for realizing the green and sustainable development of the paper industry, fully reflecting the profound significance of the integration of technology, economy, and environmental protection. Content of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a wastewater treatment process equipment and its treatment process for bamboo pulp wastewater, which solves the technical problems that in the existing technical solution of biological treatment of wastewater, the activity of microorganisms is reduced in an alkaline environment, resulting in low efficiency, long treatment cycle, difficulty in meeting high-efficiency requirements, and high operating costs, making it difficult to achieve economicization.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A wastewater treatment process equipment for bamboo and wood pulp includes a black liquor tank, which is used to store bamboo and wood pulp wastewater and conduct preliminary adjustment and uniform mixing treatment. A raw liquid pipe is provided at the input end of the black liquor tank, and the output end of the black liquor tank is connected to a chemical dosing treatment structure. The output end of the chemical dosing treatment structure is connected to a pretreatment structure. The output end of the pretreatment structure is connected to a two-stage membrane treatment structure. A fresh water recovery pipe is provided at the output end of the two-stage membrane treatment structure to discharge the high-purity fresh water treated by the second-stage membrane module for reuse to achieve water resource recycling. A chemical dosing pipe is provided on the pretreatment structure to inject specific chemical agents, and the type of agent (such as acid regulator, flocculant, filter aid, etc.) and the dosing amount can be flexibly adjusted according to the nature of the wastewater. An evaporation structure is provided on the two-stage membrane treatment structure, and the output end of the evaporation structure is connected to a concentrated liquid pipe to discharge the high-concentration liquid formed after evaporation and concentration, realizing the centralized collection of pollutants.

[0007] Preferably, the chemical dosing treatment structure includes a mixing pipe, which is used to uniformly mix the wastewater and the agent to ensure sufficient contact between the chemical regulator and the wastewater, optimize the nature of the wastewater, and provide a good water quality basis for subsequent treatment. The output end of the chemical dosing pipe is connected to the mixing pipe, and the output end of the mixing pipe is connected to the input end of the pretreatment structure; through the automated mechanical cleaning function, impurities with larger particles can be effectively removed, and at the same time, it can operate without maintenance, greatly improving the filtration efficiency and extending the service life of subsequent modules; the wastewater is further finely filtered to remove small particle suspensions and high-molecular organic substances, etc., reducing the pressure on the subsequent membrane module and protecting the high efficiency of the membrane device.

[0008] Preferably, the pretreatment structure includes a self-cleaning filtration module and a microfiltration module. The input end of the self-cleaning filtration module is connected to the output end of the mixing pipe, the output end of the self-cleaning filtration module is connected to the input end of the microfiltration module, and a high-pressure pump is connected between the input end of the self-cleaning filtration module and the input end of the microfiltration module.

[0009] Preferably, the dual - stage membrane treatment structure includes a primary membrane module and a secondary membrane module. The output end of the primary membrane module has a primary fresh - water pipe and a primary concentrated - water pipe. The primary fresh - water pipe is used to output the fresh water after membrane treatment, and the primary concentrated - water pipe is used to output the concentrated water after membrane treatment. The primary fresh - water pipe is connected to the input end of the secondary membrane module, and the primary concentrated - water pipe is connected to the input end of the evaporation structure. The output end of the secondary membrane module is provided with a return pipe, and the output end of the return pipe is connected to the input end of the primary membrane module. The return pipe is used to output the concentrated water derived from the secondary membrane module. The fresh - water recovery pipe is connected to the output end of the secondary membrane module, and the fresh - water recovery pipe is used to recover the fresh water output by the secondary membrane module. The primary membrane module preliminarily separates the dissolved pollutants and water in the wastewater through filtration, generating primary concentrated water and fresh water. The concentrated water is sent to the evaporator for further concentration, and the fresh water is sent to the secondary membrane module for in - depth treatment to further treat the primary fresh water with a higher separation accuracy, removing the remaining dissolved pollutants and generating high - purity fresh water to ensure that the chemical oxygen demand (COD) and total dissolved solids (TDS) meet the water reuse standard. The return pipe is used to recycle the concentrated water of the secondary membrane module to the primary membrane module, forming a closed - loop treatment system, reducing the generation amount of concentrated water, and improving the efficiency of wastewater resource utilization.

[0010] Preferably, the evaporation structure includes an evaporator. The output end of the primary membrane concentrated - water pipe is connected to the input end of the evaporator, and the concentrated - liquid pipe is connected to the output end of the evaporator. Using the principle of evaporation and concentration, the wastewater in the primary concentrated - water pipe is efficiently concentrated, raising the concentration of dissolved substances to 50 - 60%, greatly reducing the discharge amount of waste liquid containing pollutants, and providing convenience for subsequent resource utilization at the same time.

[0011] Preferably, a condenser is provided at the output end of the evaporator condensate. The output end of the condenser is connected to the input end of the secondary membrane module. The steam generated by the evaporator is condensed, the condensate is recovered, and the COD content is further reduced to ensure that the condensed wastewater can be recycled back to the secondary membrane module for re - filtration, improving the fresh - water recovery rate.

[0012] A wastewater treatment process for bamboo and wood pulp. First, bamboo and wood pulp black liquor with a concentration of 1-3% and a chemical oxygen demand (COD) of approximately 10,000 mg / L enters the black liquor tank. Next, the black liquor enters the mixing pipe, and the liquid medicine is sent into the dosing pipe and then enters the mixing pipe for mixing to complete the adjustment treatment. Then, the black liquor after the adjustment treatment enters the self-cleaning filtration module and the microfiltration module in sequence through a high-pressure pump for filtration. After preliminary filtration, particles and other water-insoluble impurities are removed. Then, the pretreated black liquor is sent to the first-stage membrane module. The first-stage membrane module separates the concentrated water and sends it to the first-stage membrane concentrated water pipe, and the separated fresh water is sent to the first-stage membrane fresh water pipe. The fresh water in the first-stage membrane fresh water pipe has a chemical oxygen demand (COD) of approximately 500 mg / L. After entering the second-stage membrane module, the concentrated water separated is sent back to the first-stage membrane module for re-treatment through the return pipe. The separated fresh water has a total dissolved solids (TDS) of ≤50 mg / L and a chemical oxygen demand (COD) of ≤5 mg / L for fresh water reuse. The sewage with a concentration of 20% in the first-stage membrane concentrated water pipe is evaporated by the evaporator, and the concentration of the concentrated liquid reaches 50-60% and is discharged through the concentration tank. The COD in the condensate water of the evaporator is approximately 300 mg / L, and after being treated by the condenser, it enters the second-stage membrane module for re-treatment to increase the fresh water recovery rate.

[0013] Beneficial effects

[0014] The present invention provides a wastewater treatment process equipment for bamboo and wood pulp. Through a multi-stage treatment structure, the present invention can effectively remove suspended solids, large particle impurities, organic pollutants, and chemical pollutants in the wastewater. Combining the dosing treatment and membrane filtration process, it overcomes the problem of reduced microbial activity in the traditional biological method under high alkaline conditions. Through multi-stage filtration, the process realizes rapid and efficient wastewater treatment. The entire treatment process from the wastewater entering the system to the production of fresh water only takes about 2 hours, solving the problem of the long treatment cycle (4-6 days) of the traditional biological method. Using a two-stage membrane structure and an evaporation concentration process, it can maximize the fresh water recovery rate and ensure the resource utilization of wastewater. Compared with the traditional biological method, this process does not rely on microbial activity, avoiding the high acid consumption, nutrient regulation, and high-energy consumption aeration system requirements for maintaining the survival of microorganisms. At the same time, the treated fresh water is recycled back to the process, and the concentrated water is recycled and reused through resource regeneration, achieving the dual green environmental protection goals of zero discharge and resource regeneration utilization of bamboo and wood pulp wastewater, and the overall operation economy is stronger. Description of the drawings

[0015] Figure 1 It is a schematic structural diagram of the wastewater treatment process equipment for bamboo and wood pulp described in the present invention.

[0016] Figure 2 It is a schematic flow diagram of the wastewater treatment process for bamboo and wood pulp described in the present invention.

[0017] In the figure: 1. Black liquor tank; 2. Stock solution pipe; 3. Fresh water recovery pipe; 4. Chemical dosing pipe; 5. Concentrate pipe; 6. Mixing pipe; 7. Self-cleaning filtration module; 8. Microfiltration module; 9. High-pressure pump; 10. Primary membrane module; 11. Secondary membrane module; 12. Primary fresh water pipe; 13. Primary concentrate pipe; 14. Return pipe; 15. Evaporator; 16. Condenser Specific implementation mode

[0018] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The detailed description is as follows.

[0019] The present invention provides a wastewater treatment process equipment for bamboo pulp. Through a multi-stage treatment structure, the present invention can effectively remove suspended solids, large particle impurities, organic pollutants and chemical pollutants in the wastewater. Combining chemical dosing treatment and membrane filtration processes, it overcomes the problem of reduced microbial activity in the traditional biological method under high alkaline conditions. Through multi-stage filtration, the process realizes rapid and efficient wastewater treatment. The entire treatment process from the wastewater entering the system to the production of fresh water only takes about 2 hours, solving the problem of the long treatment cycle (4 - 6 days) of the traditional biological method. Using a double-stage membrane structure and an evaporation concentration process, it can maximize the fresh water recovery rate, ensure the resource utilization of wastewater. Compared with the traditional biological method, this process does not rely on microbial activity, avoiding the high acid consumption, nutrient regulation and high energy consumption aeration system requirements for maintaining the survival of microorganisms. At the same time, the treated fresh water is recycled back to the process, and the concentrated water is recycled and reused through resource regeneration, achieving the dual green environmental protection goals of zero discharge and resource regeneration of bamboo pulp wastewater treatment, and the overall operation economy is stronger.

[0020] This embodiment is further configured such that the chemical dosing treatment structure includes a mixing pipe 6 for uniformly mixing the wastewater and the chemical agent, ensuring sufficient contact between the chemical regulator and the wastewater, optimizing the properties of the wastewater, and providing a good water quality basis for subsequent treatment. The output end of the chemical dosing pipe 4 is connected to the mixing pipe 6, and the output end of the mixing pipe 6 is connected to the input end of the pretreatment structure; through the automated mechanical cleaning function, impurities with larger particles can be effectively removed, and at the same time, maintenance-free operation can greatly improve the filtration efficiency and extend the service life of subsequent modules; the wastewater is further finely filtered to remove small particle suspended solids and high molecular weight organic matters, etc., reducing the pressure on the subsequent membrane modules and protecting the high efficiency of the membrane device.

[0021] In this embodiment, it is further set that the pretreatment structure includes a self-cleaning filtration module 7 and a microfiltration module 8. The input end of the self-cleaning filtration module 7 is connected to the output end of the mixing pipe 6, the output end of the self-cleaning filtration module 7 is connected to the input end of the microfiltration module 8, and a high-pressure pump 9 is connected between the input end of the self-cleaning filtration module 7 and the input end of the microfiltration module 8.

[0022] In this embodiment, it is further set that the two-stage membrane treatment structure includes a primary membrane module 10 and a secondary membrane module 11. The output end of the primary membrane module 10 includes a primary membrane fresh water pipe 12 and a primary membrane concentrated water pipe 13. The primary membrane fresh water pipe 12 is used to output the fresh water after membrane treatment, and the primary membrane concentrated water pipe 13 is used to output the concentrated water after membrane treatment. The primary membrane fresh water pipe 12 is connected to the input end of the secondary membrane module 11, and the primary membrane concentrated water pipe 13 is connected to the input end of the evaporation structure. The output end of the secondary membrane module 11 is provided with a return water pipe 14, and the output end of the return water pipe 14 is connected to the input end of the primary membrane module 10. The return water pipe 14 is used to output the concentrated water derived from the secondary membrane module 11. The fresh water recovery pipe 3 is connected to the output end of the secondary membrane module 11, and the fresh water recovery pipe 3 is used to recover the fresh water output by the secondary membrane module 11. The primary membrane module 10 preliminarily separates the dissolved pollutants and water in the wastewater through filtration, generating primary membrane concentrated water and fresh water; the concentrated water is sent to the evaporator 15 for further concentration, and the fresh water is sent to the secondary membrane module 11 for in-depth treatment to further treat the primary membrane fresh water with a higher separation accuracy, removing the remaining dissolved pollutants to produce high-purity fresh water, ensuring that the chemical oxygen demand (COD) and total dissolved solids (TDS) meet the water reuse standards; the return water pipe 14 is used to circulate the concentrated water of the secondary membrane module 11 to the primary membrane module 10 to form a closed-loop treatment system, reducing the amount of concentrated water generated and improving the wastewater resource utilization efficiency.

[0023] In this embodiment, it is further set that the evaporation structure includes an evaporator 15. The output end of the primary membrane concentrated water pipe is connected to the input end of the evaporator 15, and the concentrated liquid pipe 5 is connected to the output end of the evaporator 15. The wastewater in the primary membrane concentrated water pipe 13 is efficiently concentrated by using the evaporation concentration principle, and the concentration of the dissolved substances is increased to 60%, greatly reducing the discharge amount of the waste liquid containing pollutants, and at the same time facilitating subsequent resource utilization applications.

[0024] In this embodiment, it is further set that the condensate output end of the evaporator 15 is provided with a condenser 16, and the output end of the condenser 16 is connected to the input end of the secondary membrane module 11. The condensate generated by the evaporator 15 is filtered again by the secondary membrane, and the COD content is further reduced to improve the fresh water recovery rate.

[0025] A wastewater treatment process for bamboo and wood pulp. First, bamboo and wood pulp wastewater with a concentration of 1-3% and a chemical oxygen demand (COD) of approximately 10,000 mg / L enters the black liquor tank 1. Next, the black liquor enters the mixing pipe 6, and the chemical solution is sent into the dosing pipe 4 and then enters the mixing pipe 6 for mixing to complete the adjustment treatment. Then, the adjusted black liquor passes through the high-pressure pump 9 and successively enters the self-cleaning filtration module 7 and the microfiltration module 8 for filtration. After preliminary filtration, particles and other water-insoluble impurities are removed. Then, the pretreated black liquor is sent to the first-stage membrane module 10. The first-stage membrane module 10 separates the concentrated water and sends it to the first-stage membrane concentrated water pipe 13, and the separated fresh water is sent to the first-stage membrane fresh water pipe 12. The fresh water in the first-stage membrane fresh water pipe 12 has a chemical oxygen demand (COD) of approximately 500 mg / L. After entering the second-stage membrane module 11, the concentrated water separated is sent back to the first-stage membrane module 10 through the return pipe 14 for further treatment. The separated fresh water has a total dissolved solids (TDS) of ≤50 mg / L and a chemical oxygen demand (COD) of ≤5 mg / L for fresh water reuse. The concentrated water with a concentration of 20% in the first-stage membrane concentrated water pipe 13 is evaporated in the evaporator 15, and the concentration of the concentrated liquid reaches 60% and is then discharged through the concentrated liquid pipe. The COD in the condensate water of the evaporator 15 is approximately 300 mg / L. After being treated by the condenser 16, it enters the second-stage membrane module 11 for further treatment to increase the fresh water recovery rate.

[0026] Its detailed connection means are well-known techniques in the art; as Figure 1-2 shown, the bamboo and wood pulp black liquor has a concentration of 1%-3% and a COD of approximately 10,000 mg / L. The original liquid from the black liquor tank 1 is sent through a pipeline into the mixing pipe 6. Chemical regulators (such as flocculants, pH-adjusting reagents, etc.) are added to the mixing pipe 6 through the dosing pipe 4 to be fully mixed with the wastewater. The pH value of the wastewater is adjusted to optimize its physical and chemical properties and improve the subsequent filtration and treatment efficiency. The wastewater treated with the reagent enters the self-cleaning filtration module 7. Large particle impurities and suspended particles (such as bamboo and wood fiber substances) are removed, reducing the burden on subsequent filtration and membrane modules. Through the automatic cleaning function, the module can operate efficiently for a long time. The wastewater still has a COD of approximately 10,000 mg / L, but the particle impurities are significantly reduced.

[0027] The wastewater filtered by the self-cleaning module flows into the microfiltration unit for fine filtration. Small particle substances and suspended colloids are separated, further reducing the particle load entering the membrane module. The treatment efficiency and service life of the membrane separation system are improved. The particle impurities and a large amount of suspended substances in the water have been basically removed, and the wastewater stably flows into the membrane module.

[0028] The pretreated wastewater is transported to the first-stage membrane module 10 for preliminary separation of the wastewater, dividing the pollutants into two parts: fresh water and concentrated water. Quality of the treated fresh water: COD is reduced to ≈500 mg / L, and the fresh water part passes through the first-stage membrane and enters the second-stage membrane module 11 for further treatment. Output of the concentrated water: The concentrated water containing high-concentration pollutants is transferred through the first-stage membrane concentrated water pipe 13 to the evaporator 15 for treatment.

[0029] Higher-precision separation treatment is carried out on the second-stage membrane module 11, and finally pure water is produced (COD ≤ 5 mg / L, TDS ≤ 50 mg / L). At the same time, the concentrated water flows back to the first-stage membrane module 10 through the return pipe 14 for recycling treatment.

[0030] The concentrated water generated by the first-stage membrane module 10 enters the MVR (mechanical vapor recompression system) evaporator 15. Through evaporation concentration technology, the volume of the concentrated liquid is reduced, and the pollutant content is increased to 50 - 60%. The total amount of concentrated liquid that needs to be finally disposed of is reduced, saving disposal costs.

[0031] The initial wastewater has a COD of ≈10,000 mg / L, and finally, the pollutant concentration is significantly reduced, meeting the discharge or reuse standards.

[0032] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0033] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the above-disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A wastewater treatment process equipment for bamboo and wood pulp, including a black liquor tank (1), characterized in that, The input end of the black liquor tank (1) is provided with a stock solution pipe (2). The output end of the black liquor tank (1) is connected to a chemical addition treatment structure. The output end of the chemical addition treatment structure is connected to a pretreatment structure. The output end of the pretreatment structure is connected to a two-stage membrane treatment structure. The output end of the two-stage membrane treatment structure is provided with a fresh water recovery pipe (3). A chemical addition pipe (4) is arranged on the pretreatment structure. An evaporation structure is arranged on the two-stage membrane treatment structure. The output end of the evaporation structure is connected to a concentrated liquid pipe (5).

2. The wastewater treatment process equipment for bamboo pulp according to claim 1, characterized in that , The chemical addition treatment structure includes a mixing pipe (6). The output end of the chemical addition pipe (4) is connected to the mixing pipe (6). The output end of the mixing pipe (6) is connected to the input end of the pretreatment structure.

3. The wastewater treatment process equipment for bamboo pulp according to claim 2, characterized in that , The pretreatment structure includes a self-cleaning filtration module (7) and a microfiltration module (8). The input end of the self-cleaning filtration module (7) is connected to the output end of the mixing pipe (6). The output end of the self-cleaning filtration module (7) is connected to the input end of the microfiltration module (8). A high-pressure pump (9) is connected between the input end of the self-cleaning filtration module (7) and the input end of the microfiltration module (8).

4. The wastewater treatment process equipment for bamboo pulp according to claim 3, characterized in that , The two-stage membrane treatment structure includes a primary membrane module (10) and a secondary membrane module (11). The output end of the primary membrane module (10) is a primary fresh water pipe (12) and a primary concentrated water pipe (13). The primary fresh water pipe (12) is used to output the fresh water after membrane treatment. The primary concentrated water pipe (13) is used to output the concentrated water after membrane treatment. The primary fresh water pipe (12) is connected to the input end of the secondary membrane module (11). The primary concentrated water pipe (13) is connected to the input end of the evaporation structure. The output end of the secondary membrane module (11) is provided with a return water pipe (14). The output end of the return water pipe (14) is connected to the input end of the primary membrane module (10). The return water pipe (14) is used to output the concentrated water derived from the secondary membrane module (11). The fresh water recovery pipe (3) is connected to the output end of the secondary membrane module (11). The fresh water recovery pipe (3) is used to recover the fresh water output by the secondary membrane module (11).

5. The wastewater treatment process equipment for bamboo pulp according to claim 4, characterized in that , The evaporation structure includes an evaporator (15). The output end of the primary membrane concentrated water pipe is connected to the input end of the evaporator (15). The concentrated liquid pipe (5) is connected to the output end of the evaporator (15).

6. The wastewater treatment process equipment for bamboo pulp according to claim 5, characterized in that , The condensate output end of the evaporator (15) is provided with a condenser (16). The output end of the condenser (16) is connected to the input end of the secondary membrane module (11).

7. A wastewater treatment process for bamboo pulp according to any one of claims 1-6, characterized in that , First, bamboo pulp black liquor with a concentration of 1-3% and a chemical oxygen demand (COD) of approximately 10,000 mg / L enters the black liquor tank (1). Next, the black liquor enters the mixing pipe (6), and the liquid medicine is sent into the dosing pipe (4) and enters the mixing pipe (6) for mixing to complete the adjustment treatment. Then, the adjusted black liquor enters the self-cleaning filtration module (7) and the microfiltration module (8) in sequence through the high-pressure pump (9) for filtration. After preliminary filtration, particles and other water-insoluble impurities are removed. Then, the pretreated black liquor is sent to the first-stage membrane module (10). The first-stage membrane module (10) separates the concentrated water and sends it to the first-stage concentrated water pipe (13), and the separated fresh water is sent to the first-stage fresh water pipe (12). The fresh water in the first-stage fresh water pipe (12) has a chemical oxygen demand (COD) of approximately 500 mg / L. After entering the second-stage membrane module (11), the concentrated water separated is returned to the first-stage membrane module (10) through the return pipe (14) for re-treatment, while the separated fresh water has a total dissolved solid (TDS) of ≤ 50 mg / L and a chemical oxygen demand (COD) of ≤ 5 mg / L for fresh water reuse. The sewage with a concentration of 20% in the first-stage concentrated water pipe (13) is evaporated by the evaporator (15), and the concentration of the concentrated liquid reaches 60% and is discharged through the concentrated tank. The COD of the condensate water of the evaporator (15) is approximately 300 mg / L, and after being treated by the condenser (16), it enters the second-stage membrane module (11) for re-treatment to increase the fresh water recovery rate.

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