Integrated system and treatment method for separate treatment of printing and dyeing wastewater according to water quality and reclamation of reclaimed water

Abstract

An integrated system for separate treatment of printing and dyeing wastewater and reclamation of reclaimed water, comprising a centralized pretreatment system for characteristic wastewater, a pretreatment system for heavily polluted wastewater, a biochemical treatment system for mixed wastewater, a deep treatment system for mixed wastewater, a reclaimed water reuse treatment system, a compliance discharge treatment system and a sludge treatment system; the effluent of the centralized pretreatment system for characteristic wastewater is collected into the pretreatment system for heavily polluted wastewater, the effluent of the pretreatment system for heavily polluted wastewater is collected into the biochemical treatment system for mixed wastewater, the effluent of the biochemical treatment system for mixed wastewater is collected into the deep treatment system for mixed wastewater, a part of the effluent of the deep treatment system for mixed wastewater enters the reclaimed water reuse treatment system, and the other part of the effluent enters the compliance discharge treatment system. In view of the water quality characteristics of printing and dyeing wastewater, the present invention innovates an integrated separate treatment system, which has stable treatment effect, low operation cost, excellent effluent quality, realizes the recovery of organic compounds and the conservation of water resources, and has remarkable economic benefits.

Description

Technical Field

[0001] The present invention relates to the field of wastewater treatment, and particularly to an integrated system and treatment method for separate treatment of different-quality printing and dyeing wastewater and reclamation of reclaimed water. Background Art

[0002] The printing and dyeing industry is a typical high-water-consumption industry and also a major industrial pollutant discharger. The annual wastewater discharge reaches up to 3×10 9 tons, accounting for 35% of the total industrial wastewater discharge in the country, and the recovery rate is less than 10%. Printing and dyeing wastewater is the main source of textile industrial wastewater, accounting for about 80% of its total amount.

[0003] Printing and dyeing wastewater comes from different sections in the printing and dyeing process of the textile industry. There are four processes in the printing and dyeing process, including: pretreatment process, dyeing process, printing process, and finishing process. The dyes, auxiliaries, additives, etc. used in each process vary greatly, resulting in significant differences in the quality and quantity of the discharged wastewater, making it one of the industrial wastewaters that are relatively difficult to treat. Printing and dyeing wastewater has the following typical characteristics:

[0004] 1. Great variation in water quality and quantity. The production volume of the printing and dyeing industry is large. Due to the frequent changes in the types and production volumes of the finished fabrics, the water quality and quantity produced also show various differences;

[0005] 2. High chroma. In the printing and dyeing process, part of the dyes can be successfully dyed onto the fabrics, and part of the dyes will be discharged with the water. In different sections, due to the different fabrics being dyed, different dyes are used, and different dyes have different dyeing rates, resulting in a large fluctuation in the chroma of the wastewater;

[0006] 3. Great variation in pH. pH affects the dyeing rate of the sizing agent in the dyeing or printing process. In addition, different technical methods are used for dyeing different fabrics, resulting in a large change in the pH of different types of dyeing sections;

[0007] 4. High COD concentration. In different processes of the printing and dyeing industry, due to the use of printing and dyeing auxiliaries and different additives, especially synthetic macromolecular printing and dyeing auxiliaries, the wastewater shows a relatively high COD value;

[0008] 5. Poor biodegradability. Most of the pollutants in printing and dyeing wastewater are artificially synthesized substances that are difficult to degrade. In the printing and dyeing process, part of the dyes (10% - 20%) and printing and dyeing auxiliaries will be lost with the water. The common feature of these dyes and auxiliaries is that BOD5 / COD is less than 0.2, that is, the biodegradability is relatively poor;

[0009] 6. Toxic and harmful properties. Some toxic and harmful substances generated during the decomposition process of dyes and auxiliaries in nature, such as aniline compounds, some of which are carcinogenic and mutagenic. Moreover, some dyes and auxiliaries themselves have a carcinogenic tendency. Therefore, printing and dyeing wastewater has relatively high toxicity.

[0010] The sources and pollutant components of printing and dyeing wastewater are very complex. Due to the above-mentioned characteristics such as large water quality variation, high organic matter content, and high chromaticity (mainly colored dyes), direct discharge will cause great harm to human health and the living environment, and at the same time result in waste of water resources. Generally, traditional biochemical methods are mostly used to treat printing and dyeing wastewater at home and abroad to remove organic matter in the wastewater. Some factories also add a stage of physical and chemical treatment before or after biochemical treatment, and a few factories adopt multi-stage treatment. With the increasing attention of the country and society to environmental protection requirements and the requirements for sustainable development, traditional treatment methods are increasingly difficult to meet the requirements of production and environmental protection. Summary of the Invention

[0011] In view of the above situation, to overcome the defects of the prior art, the purpose of the present invention is to provide an integrated system and treatment method for separate quality treatment and reclamation of intermediate water from printing and dyeing wastewater, which can effectively solve the problem that traditional printing and dyeing wastewater treatment cannot meet the requirements of production and environmental protection.

[0012] To achieve the above purpose, the technical solution solved by the present invention is that an integrated system for separate quality treatment and reclamation of intermediate water from printing and dyeing wastewater includes a characteristic wastewater centralized pretreatment system, a heavily polluted wastewater pretreatment system, a mixed wastewater biochemical treatment system, a mixed wastewater advanced treatment system, an intermediate water reclamation treatment system, a standard discharge treatment system, and a sludge treatment system; the effluent of the characteristic wastewater centralized pretreatment system is collected into the heavily polluted wastewater pretreatment system, the effluent of the heavily polluted wastewater pretreatment system is collected into the mixed wastewater biochemical treatment system, the effluent of the mixed wastewater biochemical treatment system is collected into the mixed wastewater advanced treatment system, and a part of the effluent of the mixed wastewater advanced treatment system enters the intermediate water reclamation treatment system, and the other part of the effluent enters the standard discharge treatment system.

[0013] The treatment method of the integrated system for separate quality treatment and reclamation of intermediate water from printing and dyeing wastewater includes the following steps:

[0014] S1. Characteristic wastewater centralized pretreatment: Desizing wastewater and alkali weight reduction wastewater enter the characteristic wastewater pretreatment system. After the desizing wastewater is treated by "crosslinking salting out + hydrolysis acidification + anaerobic treatment + biological contact oxidation + Fenton oxidation", organic compounds are removed. After the alkali weight reduction wastewater is treated by "acid precipitation + plate and frame pressure filtration", alkalinity is removed. The effluent of the characteristic wastewater pretreatment system is collected into the heavily polluted wastewater pretreatment system;

[0015] S2. Pretreatment of heavily polluted wastewater: The heavily polluted wastewater from printing and dyeing is mixed with the effluent from the characteristic wastewater pretreatment system and then enters the heavily polluted wastewater pretreatment system for acid-base adjustment, coagulation and precipitation to remove fine suspended solids and part of the dissolved organic matter.

[0016] S3. Main biochemical treatment of mixed wastewater: The effluent from the heavily polluted wastewater pretreatment system is mixed with the lightly polluted wastewater from printing and dyeing and then enters the mixed wastewater biochemical treatment system to effectively remove organic matter, ammonia nitrogen and suspended solids in the wastewater.

[0017] S4. Advanced treatment of mixed wastewater: The effluent from the mixed wastewater biochemical treatment system enters the mixed wastewater advanced treatment system. The strong oxidation ability of ozone is used to treat the refractory biodegradable organic matter, and the biofilm attached to the packing of the biological aerated filter is used to remove the residual COD and BOD5, and the fiber bundle filter further removes the suspended solids.

[0018] S5. Reclaimed water reuse treatment: Part of the effluent from the fiber bundle filter enters the reclaimed water reuse treatment system for "ultrafiltration + nanofiltration" treatment, and the effluent is reused for production.

[0019] S6. Standard discharge treatment: The concentrated water generated by the nanofiltration membrane system and the other part of the effluent from the fiber bundle filter enter the standard discharge treatment system for secondary ozone oxidation treatment, and then enter the MBR reactor for further advanced treatment and then discharge up to standard.

[0020] S7. Sludge treatment: The precipitates from the heavily polluted wastewater pretreatment system, the mixed wastewater biochemical treatment system and the mixed wastewater advanced treatment system are discharged into the sludge treatment system for concentration and dehydration.

[0021] In view of the water quality characteristics of printing and dyeing wastewater, the present invention innovatively integrates a separate quality treatment system, which has stable treatment effect, low operation cost, and the effluent quality is better than the requirements of the first-class A standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002), with significant environmental benefits; the application of the characteristic wastewater pretreatment and reclaimed water reuse system realizes the recovery of organic compounds and the conservation of water resources, with significant economic benefits. Brief Description of the Drawings

[0022] Figure 1 is the process flow chart of the present invention. Detailed Embodiments

[0023] The following detailed description of the specific embodiments of the present invention is made in conjunction with the drawings and embodiments.

[0024] Given in combination with the attached drawings, an integrated system for separate treatment of printing and dyeing wastewater and reclamation of reclaimed water, the system includes a characteristic wastewater centralized pretreatment system, a heavily polluted wastewater pretreatment system, a mixed wastewater biochemical treatment system, a mixed wastewater advanced treatment system, a reclaimed water reuse treatment system, a compliance discharge treatment system and a sludge treatment system; the effluent of the characteristic wastewater centralized pretreatment system is collected into the heavily polluted wastewater pretreatment system, the effluent of the heavily polluted wastewater pretreatment system is collected into the mixed wastewater biochemical treatment system, the effluent of the mixed wastewater biochemical treatment system is collected into the mixed wastewater advanced treatment system, a part of the effluent of the mixed wastewater advanced treatment system enters the reclaimed water reuse treatment system, and the other part of the effluent enters the compliance discharge treatment system.

[0025] As shown in the attached Figure 1 drawings, the characteristic wastewater centralized pretreatment system includes a cross-linking salting-out tank 1, a hydrolysis acidification tank 2, an anaerobic reactor 3, a biological contact oxidation tank 4 and a Fenton oxidation tank 7 connected in sequence through pipelines, and a wastewater regulation tank 5 and an acid precipitation reaction tank 6 connected in sequence through pipelines; the heavily polluted wastewater pretreatment system includes a grille channel 8, an acid-base regulation tank 9, a coagulation sedimentation tank 10 and a regulation tank 11 connected in sequence; the mixed wastewater biochemical treatment system includes an anaerobic / anoxic / aerobic tank 12, a high-efficiency sedimentation tank 13 and an intermediate water tank 14 connected in sequence; the mixed wastewater advanced treatment system includes a first ozone oxidation tank 15, an aerated biological filter 16 and a fiber bundle filter 17 connected in sequence; the reclaimed water reuse treatment system includes an ultrafilter 21, a nanofiltration membrane system 22 and a reclaimed water clear water tank 23 connected in sequence; the compliance discharge treatment system includes a second ozone oxidation tank 18 and an MBR reactor 19 connected in sequence, the concentrated water outlet of the nanofiltration membrane system 22 is connected to the inlet of the second ozone oxidation tank 18 through a pipeline, the effluent of the MBR reactor 19 enters the compliance clear water tank 20, and the sludge treatment system includes a sludge thickening tank 24 and a plate and frame filter press 25 connected in sequence; wherein, the water outlets of the Fenton oxidation tank 7 and the acid precipitation reaction tank 6 are connected to the inlet of the acid-base regulation tank 9 through pipelines; the water outlet of the regulation tank 11 is connected to the anaerobic / anoxic / aerobic tank 12 through a pipeline, the water outlet of the intermediate water tank 14 is connected to the inlet of the first ozone oxidation tank 15 through a pipeline, the water outlet of the fiber bundle filter 17 is connected to the inlets of the second ozone oxidation tank 18 and the ultrafilter 21 through pipelines respectively, the sedimentation outlets of the coagulation sedimentation tank 10, the anaerobic / anoxic / aerobic tank 12, the high-efficiency sedimentation tank 13, the intermediate water tank 14 and the fiber bundle filter 17 are connected to the inlet of the sludge thickening tank 24 through pipelines, and the supernatant outlet of the sludge thickening tank 24 and the backwashing water outlet of the aerated biological filter 16 are connected to the inlet of the coagulation sedimentation tank 10 through pipelines.

[0026] The treatment method of the above-mentioned integrated system for separate treatment of printing and dyeing wastewater and reclamation of reclaimed water includes the following steps:

[0027] S1. Centralized pretreatment of characteristic wastewater: The characteristic wastewater includes desizing wastewater and alkali weight reduction wastewater. For the desizing wastewater, acid such as sulfuric acid is first added to adjust the pH to 8.5 - 9.5, and then it enters the cross - linked salting - out tank 1 with a hydraulic retention time of 30 min. 60% of PVA is precipitated through salting - out and flocculation reactions. The effluent enters the hydrolysis acidification tank 2 with a hydraulic retention time of 30 h and a packing filling rate of 50% in the tank. The effluent is pumped to the anaerobic reactor 3 with a volumetric loading of 4.0 kg COD / (m 3 •d), an upward flow velocity of 0.5 m / h, and some organic pollutants are degraded. The anaerobic effluent enters the biological contact oxidation tank 4 with a hydraulic retention time of 24 h to remove some organic matters and color. After precipitation and separation, acid is added to adjust the pH to 2.5 - 3.5, and then it enters the Fenton oxidation tank 7 to remove refractory organic pollutants with a hydraulic retention time of 5 h. The effluent flows into the acid - base adjustment tank 9; The alkali weight reduction wastewater is centrally collected into the wastewater adjustment tank 5 with a hydraulic retention time of 18 h, and then acid such as sulfuric acid is added to adjust the pH to 3 - 4. The reaction time in the acid precipitation reaction tank 6 is 20 min. The precipitate is dehydrated and TA (terephthalic acid) is recovered by an anti - corrosion polypropylene chamber filter press. The filtrate of the filter press flows into the acid - base adjustment tank 9; Among them, the COD removal rate of the effluents from the Fenton oxidation tank 7 and the acid precipitation reaction tank 6 is more than 70%, the PVA removal rate is more than 80%, and the color removal rate is more than 50%;

[0028] S2. Pretreatment of heavily polluted wastewater: The heavily polluted wastewater from dyeing and printing flows into the acid - base adjustment tank 9 through the grid channel 8, and is mixed with the pickled alkali weight reduction wastewater and the pretreated desizing wastewater. The mixed wastewater enters the coagulation sedimentation tank 10, and PAM 5 - 10 mg / L and PAC 100 - 200 mg / L are added. Coagulation is carried out for 30 min and the sedimentation time is 3 h. The effluent enters the adjustment tank 11;

[0029] S3. Main biochemical treatment of the mixed wastewater: The lightly polluted wastewater from dyeing and printing flows into the adjustment tank 11 through the grid channel, and is mixed with the pretreated heavily polluted wastewater from dyeing and printing. Acid (such as sulfuric acid) is added to adjust the pH to 6.5 - 8.5. The wastewater is pumped to the anaerobic / anoxic / aerobic tank 12 with a hydraulic retention time of 35 h, a sludge loading of 0.08 kg BOD5 / (kg MLSS •d), a mixed liquor reflux ratio of 100 - 400%, and a sludge reflux ratio of 40 - 100%. Most of the organic matters are removed, and the COD and NH3 - N removal rates are both above 80%. The aerobic effluent enters the high - efficiency sedimentation tank 13, and then PAM 5 - 10 mg / L and PAC 100 - 200 mg / L are added in the high - efficiency sedimentation tank 13. The surface loading of the sedimentation tank is 2.4 m 3 / m 2 •h, and some suspended solids and color are removed. The effluent from the high - efficiency sedimentation tank 13 enters the intermediate water tank 14;

[0030] S4. Advanced treatment of the mixed wastewater: The wastewater in the intermediate water tank 14 flows into the ozone oxidation tank 15 with a hydraulic retention time of 1.4 h. An ozone generator is equipped to oxidize and decompose organic substances and decolorize. The effluent from the ozone oxidation tank 15 enters the biological aerated filter 16 filled with activated carbon packing. The volumetric loading is 0.16 kg BOD5 / (m 3 filter media • d), and the hydraulic retention time is 5.4 h. The effluent from the biological aerated filter 16 is pumped to the fiber bundle filter 17. The filtration rate of the fiber bundle filter is ≥ 20 m / h, the backwashing water intensity is 8 L / (m 2 • s), and the backwashing air intensity is 60 L / (m 2 • s), with a hydraulic retention time of 1.1 h;

[0031] S5. Reclaimed water reuse treatment: A part of the effluent from the fiber bundle filter 17 enters the ultrafilter 21 for filtration, and then the filtered water enters the nanofiltration membrane system 22. The ultrafilter 21 uses activated carbon tubular filter elements as the filtration components with a filtration accuracy of 5 μm. The initial desalination rate of the nanofiltration membrane system 22 is ≥ 70%, and the recovery rate is ≥ 75%. Most of the remaining COD, BOD5, SS, coliforms, and chromaticity in the water are removed. The effluent from the nanofiltration membrane system 22 enters the reclaimed water clean water tank 23. The COD and NH3-N in the effluent from the reclaimed water clean water tank 23 are reduced to below 30 mg / L and 1.0 mg / L, which is better than the water quality requirements of "Water Quality Index for Reclaimed Water in Textile Dyeing and Finishing Industry" (FZ / T 01107 - 2011), and can be reused in enterprise production to save fresh water resources;

[0032] S6. Standard discharge treatment: Another part of the effluent from the fiber bundle filter 17 and the nanofiltration concentrate from the nanofiltration membrane system 22 are mixed and enter the ozone oxidation tank 18 with a hydraulic retention time of 1.4 h. An ozone generator is equipped to further oxidize and decompose organic substances and decolorize. The effluent from the ozone oxidation tank 18 enters the MBR reactor 19. By using the microbial biodegradation effect and the membrane module interception effect, organic substances, inorganic substances, activated sludge, suspended solids, various colloids, and most bacteria are removed. The hydraulic retention time is 7 h. The effluent from the MBR reactor 19 enters the standard discharge clean water tank 20 and is disinfected with sodium hypochlorite finished products. The hydraulic retention time is 50 min. After killing the pathogenic microorganisms in the wastewater, it is discharged up to the standard. The COD and NH3-N in the effluent from the standard discharge clean water tank 20 are reduced to below 40 mg / L and 2.0 mg / L, and the drainage water quality is better than the first-class A standard requirements of "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918 - 2002). While reducing the pollutant emissions, the water environment carrying capacity is improved;

[0033] S7. Sludge treatment: The sedimentation from the coagulation sedimentation tank 10, anaerobic / anoxic / aerobic tank 12, high-efficiency sedimentation tank 13, intermediate water tank 14 and fiber bundle filter 17 is discharged into the sludge thickening tank 24. After thickening in the sludge thickening tank 24, it enters the plate and frame filter press 25 for dehydration. The dry sludge is transported out for disposal. The supernatant after thickening in the sludge thickening tank 24 and the backwash water of the biological aerated filter 16 are returned to the coagulation sedimentation tank 10 for further treatment.

[0034] The treatment method of the present invention has stable effects and low operating costs, and has been implemented on-site, effectively meeting the requirements of production and environmental protection. The relevant embodiments are as follows: Embodiment

[0035] In a printing and dyeing industrial park in a certain industrial agglomeration area in Henan, the woven printing and dyeing scale is 100 million m, and the knitted printing and dyeing scale is 70,000 tons. A new sewage treatment plant with a daily treatment capacity of 20,000 tons is built. The sewage treatment process adopts the core technology of the present invention (characteristic wastewater centralized pretreatment + heavy pollution mixed wastewater pretreatment + mixed wastewater biochemical treatment + mixed wastewater advanced treatment + reuse treatment / standard discharge treatment) to perform quality-based treatment and reclaimed water reuse on the wastewater in the printing and dyeing industrial park.

[0036] The characteristic wastewater mainly includes desizing wastewater and alkali weight reduction wastewater. The desizing wastewater is 1000 tons per day, with water quality of COD ≤ 20000 mg / L, BOD5 ≤ 4000 mg / L, PVA ≤ 3500 mg / L, and pH 12 - 13. After being treated by "crosslinking salting out + hydrolysis acidification + anaerobic treatment + biological contact oxidation + Fenton oxidation" in the centralized pretreatment system for characteristic wastewater of the present invention, the COD ≤ 820 mg / L, BOD5 ≤ 210 mg / L, PVA ≤ 600 mg / L, and pH 3.5 - 4.0; the alkali weight reduction wastewater is 1000 tons per day, with water quality of COD ≤ 20000 mg / L, BOD5 ≤ 8000 mg / L, chromaticity ≤ 8 mg / L, and pH 12 - 14. After being treated by "acid precipitation + plate and frame filtration" in the centralized pretreatment system for characteristic wastewater of the present invention, the COD ≤ 6000 mg / L, BOD5 ≤ 4000 mg / L, chromaticity ≤ 4 mg / L, and pH 3.5 - 4.0; the heavily polluted wastewater such as dyeing and printing is 5000 tons per day, with water quality of COD ≤ 2500 mg / L, BOD5 ≤ 600 mg / L, NH3-N ≤ 200 mg / L, chromaticity ≤ 600 mg / L, PVA ≤ 100 mg / L, and pH 9.5 - 10. The heavily polluted wastewater is mixed with the treated characteristic wastewater in the acid-base adjustment tank, and then after coagulation and sedimentation treatment, it is mixed with 13000 tons per day of lightly polluted printing and dyeing water (water quality: COD ≤ 600 mg / L, BOD5 ≤ 120 mg / L, NH3-N ≤ 30 mg / L, chromaticity ≤ 100 mg / L, pH 8.0 - 8.5) in the adjustment tank. The 20000 tons per day of mixed wastewater is treated by the combined process of "main biochemical treatment (anaerobic / anoxic / aerobic tank + high-efficiency sedimentation tank) + advanced treatment (ozone oxidation + biological aerated filter + fiber bundle filter)". 9000 tons per day of the effluent from the fiber bundle filter is diverted into the "ultrafiltration + nanofiltration" reuse treatment system, with a water production of 6000 tons per day. The quality of the recycled water is COD ≤ 30 mg / L, BOD5 ≤ 6 mg / L, NH3-N ≤ 1.0 mg / , and pH 7.5 - 8.5; the 3000 tons per day of concentrated water generated by the nanofiltration system is mixed with another 11000 tons per day of the effluent from the fiber bundle filter, and after being treated by "ozone oxidation + MBR", it enters the clear water tank for discharge. The water quality is COD ≤ 40 mg / L, BOD5 ≤ 8 mg / L, NH3-N ≤ 2.0 mg / L, chromaticity ≤ 5.0 mg / L, PVA ≤ 10 mg / L, and pH 6.5 - 8.5, and it is discharged near the river after meeting the standards. After calculation, the comprehensive treatment cost of the wastewater in this printing and dyeing industrial park is 8.92 yuan per ton of water, saving more than 20% in treatment cost compared with the traditional treatment method.

[0037] While conducting on-site experiments on Example 1 of the present invention, on-site experiments were also carried out on the printing and dyeing wastewater of other enterprises, and the same or similar results as those of Example 1 were obtained. They are not listed one by one here, indicating that the present invention has good effects and the treatment effects are stable and reliable.

[0038] As can be seen from the above, compared with the prior art, the present invention innovatively integrates a separate quality treatment system according to the water quality characteristics of printing and dyeing wastewater. The application of the characteristic wastewater pretreatment reduces the operation risk and operation cost of the subsequent treatment process. The integrated system of the present invention has stable treatment effects and low operation costs. The comprehensive operation cost is not higher than 9.72 yuan per ton of water, and the treatment cost is saved by more than 20%. The effluent water quality is better than the requirements of the first-class A standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002), and the environmental benefits are significant; the application of the characteristic wastewater pretreatment and the reclaimed water reuse system realizes the recovery of organic compounds and the conservation of water resources, and the economic and social benefits are significant.

Claims

1. An integrated system for separate treatment of printing and dyeing wastewater and reclamation of reclaimed water, characterized in that, The system includes a characteristic wastewater centralized pretreatment system, a heavily polluted wastewater pretreatment system, a mixed wastewater biochemical treatment system, a mixed wastewater advanced treatment system, a reclaimed water reuse treatment system, a discharge standard treatment system, and a sludge treatment system; The effluent of the characteristic wastewater centralized pretreatment system is collected into the heavily polluted wastewater pretreatment system, the effluent of the heavily polluted wastewater pretreatment system is collected into the mixed wastewater biochemical treatment system, the effluent of the mixed wastewater biochemical treatment system is collected into the mixed wastewater advanced treatment system, a part of the effluent of the mixed wastewater advanced treatment system enters the reclaimed water reuse treatment system, and the other part of the effluent enters the discharge standard treatment system; The characteristic wastewater centralized pretreatment system includes a crosslinking salting-out tank (1), a hydrolysis acidification tank (2), an anaerobic reactor (3), a biological contact oxidation tank (4), and a Fenton oxidation tank (7) connected in sequence through pipelines, and a wastewater regulation tank (5) and an acid precipitation reaction tank (6) connected in sequence through pipelines. The wastewater reacts in the acid precipitation reaction tank (6), and the precipitate is dehydrated and recovered by an anti-corrosion polypropylene box filter press; the heavily polluted wastewater pretreatment system includes a grille channel (8), an acid-base regulation tank (9), a coagulation sedimentation tank (10), and a regulation tank (11) connected in sequence; the mixed wastewater biochemical treatment system includes an anaerobic / anoxic / aerobic tank (12), a high-efficiency sedimentation tank (13), and an intermediate water tank (14) connected in sequence; the mixed wastewater advanced treatment system includes a first ozone oxidation tank (15), an aerated biological filter (16), and a fiber bundle filter (17) connected in sequence; the reclaimed water reuse treatment system includes an ultrafilter (21), a nanofiltration membrane system (22), and a reclaimed water clean water tank (23) connected in sequence; the discharge standard treatment system includes a second ozone oxidation tank (18) and an MBR reactor (19) connected in sequence. The concentrated water outlet of the nanofiltration membrane system (22) is connected to the inlet of the second ozone oxidation tank (18) through a pipeline. The effluent of the MBR reactor (19) enters the discharge standard clean water tank (20). The sludge treatment system includes a sludge thickening tank (24) and a plate and frame filter press (25) connected in sequence; among them, the water outlets of the Fenton oxidation tank (7) and the acid precipitation reaction tank (6) are connected to the water inlet of the acid-base regulation tank (9) through pipelines; the water outlet of the regulation tank (11) is connected to the anaerobic / anoxic / aerobic tank (12) through a pipeline, the water outlet of the intermediate water tank (14) is connected to the water inlet of the first ozone oxidation tank (15) through a pipeline, the water outlet of the fiber bundle filter (17) is connected to the water inlets of the second ozone oxidation tank (18) and the ultrafilter (21) through pipelines respectively, and the sediment outlets of the coagulation sedimentation tank (10), the anaerobic / anoxic / aerobic tank (12), the high-efficiency sedimentation tank (13), the intermediate water tank (14), and the fiber bundle filter (17) are connected to the inlet of the sludge thickening tank (24) through pipelines. The supernatant outlet of the sludge thickening tank (24) and the backwash water outlet of the aerated biological filter (16) are connected to the water inlet of the coagulation sedimentation tank (10) through pipelines.

2. The treatment method of the integrated system for separate treatment of printing and dyeing wastewater and reclamation of reclaimed water according to claim 1, wherein, It includes the following steps: S1. Centralized pretreatment of characteristic wastewater: Desizing wastewater and alkali weight reduction wastewater enter the characteristic wastewater pretreatment system. After the desizing wastewater is treated by "crosslinking salting out + hydrolysis acidification + anaerobic treatment + biological contact oxidation + Fenton oxidation", organic compounds are removed. After the alkali weight reduction wastewater is treated by "acid precipitation + plate and frame filtration", alkalinity is removed. The effluent of the characteristic wastewater pretreatment system is collected into the heavily polluted wastewater pretreatment system; S2. Pretreatment of heavily polluted wastewater: Printing and dyeing heavily polluted wastewater is mixed with the effluent of the characteristic wastewater pretreatment system and then enters the heavily polluted wastewater pretreatment system for acid-base adjustment and coagulation precipitation to remove fine suspended solids and some dissolved organic matter; S3. Main biochemical treatment of mixed wastewater: The effluent of the heavily polluted wastewater pretreatment system is mixed with printing and dyeing lightly polluted wastewater and then enters the mixed wastewater biochemical treatment system to effectively remove organic matter, ammonia nitrogen and suspended solids in the wastewater; S4. Advanced treatment of mixed wastewater: The effluent of the mixed wastewater biochemical treatment system enters the mixed wastewater advanced treatment system. The strong oxidation ability of ozone is used to treat refractory biodegradable organic matter. The biofilm attached to the filler of the biological aerated filter (16) is used to remove residual COD and BOD5, and the fiber bundle filter (17) further removes suspended solids; S5. Reclaimed water reuse treatment: Part of the effluent of the fiber bundle filter (17) enters the reclaimed water reuse treatment system for "ultrafiltration + nanofiltration" treatment, and the effluent is reused for production; S6. Standard discharge treatment: The concentrated water generated by the nanofiltration membrane system (22) and the other part of the effluent of the fiber bundle filter (17) enter the standard discharge treatment system for secondary ozone oxidation treatment, and then enter the MBR reactor (19) for further advanced treatment and then discharge up to standard; S7. Sludge treatment: The precipitates of the heavily polluted wastewater pretreatment system, the mixed wastewater biochemical treatment system and the mixed wastewater advanced treatment system are discharged into the sludge treatment system for concentration and dehydration.

3. The treatment method of the integrated system for separate treatment of printing and dyeing wastewater and reclamation of reclaimed water according to claim 2, characterized in that, It includes the following steps: S1. Centralized pretreatment of characteristic wastewater: The characteristic wastewater includes desizing wastewater and alkali weight reduction wastewater. The desizing wastewater is first acidified and the pH is adjusted to 8.5 - 9.5, and then it enters the crosslinking salting out tank (1) with a hydraulic retention time of 30 min. The effluent enters the hydrolysis acidification tank (2) with a hydraulic retention time of 30 h. The effluent is pumped to the anaerobic reactor (3) to degrade part of the organic pollutants. The anaerobic effluent enters the biological contact oxidation tank (4) with a hydraulic retention time of 24 h to remove part of the organic matter and color. After the effluent is separated by precipitation, acid is added to adjust the pH to 2.5 - 3.5 and it enters the Fenton oxidation tank (7) to remove refractory organic pollutants with a hydraulic retention time of 5 h. The effluent flows into the acid-base adjustment tank (9); The alkali weight reduction wastewater is centrally collected into the wastewater adjustment tank (5) with a hydraulic retention time of 18 h, and then acid is added to adjust the pH to 3 - 4. The reaction time in the acid precipitation reaction tank (6) is 20 min. The precipitate is filtered and dehydrated to recover TA, and the filtrate of the filter press flows into the acid-base adjustment tank (9); S2. Pretreatment of heavily polluted wastewater: The heavily polluted wastewater from dyeing and printing flows into the acid-base adjustment tank (9) through the grille channel (8), mixes with the alkali reduction wastewater after pickling and the desizing wastewater after pretreatment. The mixed wastewater enters the coagulation sedimentation tank (10), where PAM 5 - 10 mg / L and PAC 100 - 200 mg / L are added, coagulation is carried out for 30 min, and the sedimentation time is 3 h. The effluent enters the adjustment tank (11). S3. Main biochemical treatment of mixed wastewater: The lightly polluted wastewater from dyeing and printing flows into the adjustment tank (11), mixes with the pretreated heavily polluted wastewater from dyeing and printing. The pH is adjusted to 6.5 - 8.5 with acid, and the wastewater is pumped to the anaerobic / anoxic / aerobic tank (12) with a hydraulic retention time of 35 h to remove most of the organic matter. The effluent from the aerobic tank enters the high-efficiency sedimentation tank (13), where PAM 5 - 10 mg / L and PAC 100 - 200 mg / L are added to remove part of the suspended solids and color. The effluent from the high-efficiency sedimentation tank (13) enters the intermediate water tank (14). S4. Advanced treatment of mixed wastewater: The wastewater in the intermediate water tank (14) flows into the first ozone oxidation tank (15) with a hydraulic retention time of 1.4 h to oxidize and decompose organic matter and decolorize. The effluent from the first ozone oxidation tank (15) enters the biological aerated filter (16) with a hydraulic retention time of 5.4 h. The effluent from the biological aerated filter (16) is pumped to the fiber bundle filter (17) with a hydraulic retention time of 1.1 h. S5. Reclaimed water reuse treatment: Part of the effluent from the fiber bundle filter (17) enters the ultrafilter (21), and the filtered effluent enters the nanofiltration membrane system (22) to remove most of the remaining COD, BOD5, SS, coliforms and color in the water. The effluent from the nanofiltration membrane system (22) enters the reclaimed water clean water tank (23) for reuse in production. S6. Standard discharge treatment: The other part of the effluent from the fiber bundle filter (17) and the nanofiltration concentrate from the nanofiltration membrane system (22) are mixed and enter the second ozone oxidation tank (18) with a hydraulic retention time of 1.4 h to further oxidize and decompose organic matter and decolorize. The effluent from the second ozone oxidation tank (18) enters the MBR reactor (19) to remove organic matter, inorganic matter, activated sludge, suspended solids, various colloids and most bacteria with a hydraulic retention time of 7 h. The effluent from the MBR reactor (19) enters the standard discharge clean water tank (20), and is disinfected with finished sodium hypochlorite with a hydraulic retention time of 50 min. After killing the pathogenic microorganisms in the wastewater, it is discharged up to the standard. S7. Sludge treatment: The sediments from the coagulation sedimentation tank (10), anaerobic / anoxic / aerobic tank (12), high-efficiency sedimentation tank (13), intermediate water tank (14) and fiber bundle filter (17) are discharged into the sludge thickening tank (24), concentrated in the sludge thickening tank (24), and then enter the plate and frame filter press (25) for dehydration. The dry sludge is transported out for disposal. The supernatant after concentration in the sludge thickening tank (24) and the backwashing water from the biological aerated filter (16) are returned to the coagulation sedimentation tank (10) for further treatment.

4. The treatment method of the integrated system for separate treatment of printing and dyeing wastewater and reclamation of reclaimed water according to claim 2 or 3, characterized in that, In the described step S1, centralized pretreatment of characteristic wastewater removes organic compounds and alkalinity from desizing wastewater and alkali weight reduction wastewater, with a COD removal rate of over 70%, a PVA removal rate of over 80%, and a chromaticity removal rate of over 50%.

5. The treatment method of the integrated system for separate treatment of printing and dyeing wastewater and reclamation of reclaimed water according to claim 2 or 3, characterized in that, In the described step S3, the main biochemical treatment of mixed wastewater is anaerobic / anoxic / aerobic treatment, with a hydraulic retention time of 35 h, a mixed liquor reflux ratio of 100 - 400%, and a sludge reflux ratio of 40 - 100%. The removal rates of both COD and NH3-N are over 80%.

6. The treatment method of the integrated system for separate treatment of printing and dyeing wastewater and reclamation of reclaimed water according to claim 2 or 3, characterized in that In the described step S5, the effluent of reclaimed water reuse treatment has the COD and NH3-N reduced to below 30 mg / L and 1.0 mg / L respectively. In step S6, the effluent of up-to-standard discharge treatment has the COD and NH3-N reduced to below 40 mg / L and 2.0 mg / L respectively.

7. The treatment method of the integrated system for separate treatment of printing and dyeing wastewater and reclamation of reclaimed water according to claim 3, characterized in that, The anaerobic reactor (3) has a volume loading of 4.0 kg COD / (m 3 •d), and an upward flow velocity of 0.5 m / h; the surface loading of the high-efficiency sedimentation tank (13) is 2.4 m 3 / (m 2 •h); both the first ozone oxidation tank (15) and the second ozone oxidation tank (18) are equipped with ozone generators; the biological aerated filter (16) is filled with activated carbon packing inside, and the volume loading is 0.16 kg BOD5 / (m 3 filter media•d); the filtration rate of the fiber bundle filter (17) is ≥20 m / h, the backwashing water intensity is 8 L / (m 2 •s), and the backwashing gas intensity is 60 L / (m 2 •s).

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