Method and system for treating anthraquinone-based dyeing pigment wastewater based on multi-stage cooperation

Abstract

The present application relates to a kind of anthraquinone-based dyeing pigment wastewater treatment method and system based on multistage cooperation, belong to industrial wastewater treatment technical field, solve the problems of low COD removal rate, poor nitrification denitrification and difficult decolorization in the prior art of anthraquinone-based dye wastewater treatment method.The method comprises: respectively pretreating anthraquinone-based dye wastewater, azo pigment non-ink lake wastewater and azo pigment ink lake wastewater, the pretreatment of anthraquinone-based dye wastewater includes sequentially flocculation adsorption treatment, filter pressing dewatering treatment and ozone catalytic oxidation treatment;Mix the above wastewater and other wastewater in the factory area after pretreatment, carry out multistage biochemical intensification treatment to the obtained mixed wastewater;The mixed wastewater after biochemical intensification treatment is carried out sedimentation sludge-water separation, and the supernatant separated is carried out multistage physical and chemical synergistic treatment.The present application can improve COD removal rate and nitrification denitrification, decolorization effect.

Description

Technical Field

[0001] This invention relates to the field of industrial wastewater treatment technology, and in particular to a method and system for treating anthraquinone-containing dye wastewater based on multi-stage synergistic processes. Background Technology

[0002] Anthraquinone is the core intermediate for synthesizing anthraquinone reactive dyes and acid anthraquinone dyes. By introducing different substituents (such as amino, phenylamino, hydroxyl, sulfonic acid groups, etc.) into the anthraquinone structure, a variety of brightly colored and stable dyes can be prepared, which are widely used in the synthesis of high-performance dyes, and are indispensable in the fields of high-end textiles and special materials.

[0003] Because anthraquinone contains two ketone groups and three fused benzene rings, anthraquinone dye synthesis wastewater is characterized by strong alkalinity (usually pH 11-13), high COD (usually 20,000-30,000 mg / L), high color (usually 10,000-20,000 times), high salinity (salt content > 3%), and recalcitrant organic matter (such as 1-amino-4-bromo-2-sulfonic acid anthraquinone and compounds containing aniline groups). It is difficult to treat, direct biological treatment is difficult to carry out, and the treated water quality is difficult to meet the standards.

[0004] Existing pretreatment methods for anthraquinone dye wastewater include: (1) physical methods: using activated carbon and other adsorption materials to remove COD, color, etc.; using special membrane filtration; (2) chemical methods: using Fenton or Fenton-like processes to remove COD and color; using wet oxidation to remove COD and color under high temperature and high pressure conditions; using incineration processes to directly feed wastewater into an incinerator for high-temperature combustion; (3) biological methods: screening special strains of bacteria to degrade organic matter.

[0005] The existing pretreatment methods for anthraquinone dye wastewater have the following defects: (1) Activated carbon and other adsorbent materials are difficult to regenerate after adsorption saturation, and the regeneration cost is high. After regeneration, they will still face the treatment of regeneration discharge. Membrane filtration is easy to clog, and the membrane material needs to be cleaned frequently. The concentrated liquid after membrane filtration still needs to be further treated. (2) Fenton or Fenton-like oxidation requires adjusting the pH to acidic first for reaction, and then adjusting it to alkaline for precipitation. Since anthraquinone wastewater is mostly strongly alkaline, after repeated pH adjustment, not only is the acid and alkali consumption and chemical sludge production large, but the introduction of salt also further increases the difficulty of subsequent treatment. Wet oxidation and incineration have high operation requirements, high investment and high energy consumption, and are generally only used for small-scale treatment. (3) It is difficult to screen special strains in biological methods and the strains are difficult to apply on a large scale. The difficulty and cost are extremely high. Direct biochemical treatment of anthraquinone wastewater will inhibit the activity of biochemical activated sludge due to the presence of high salt and toxic groups, directly reducing the effect of COD removal and nitrification. In severe cases, the biochemical system may even collapse directly. Summary of the Invention

[0006] Based on the above analysis, the embodiments of the present invention aim to provide a method and system for treating anthraquinone-containing dye and pigment wastewater based on multi-stage synergy, in order to solve the problems of low COD removal rate, poor nitrification and denitrification, and difficulty in decolorization in existing methods for treating anthraquinone-containing dye and pigment wastewater.

[0007] On one hand, the present invention provides a method for treating anthraquinone-containing dye wastewater based on multi-stage synergistic treatment, the method comprising:

[0008] Step (1) Pre-treats the anthraquinone dye wastewater, the azo pigment non-lake wastewater, and the azo pigment lake wastewater respectively. The pre-treatment of the anthraquinone dye wastewater includes sequential flocculation adsorption treatment, pressure filtration dewatering treatment, and ozone catalytic oxidation treatment.

[0009] Step (2) involves mixing the anthraquinone dye wastewater, azo pigment lake-free wastewater, and azo pigment lake-containing wastewater that have been pretreated in step (1) with other wastewater from the plant area, and subjecting the resulting mixed wastewater to multi-stage synergistic biochemical enhancement treatment. The biochemical enhancement treatment includes sequential hydrolysis acidification treatment, anoxic treatment, and aerobic treatment. The aerobic treatment is a moving bed biofilm reaction treatment.

[0010] Step (3) involves sedimentation and mud-water separation of the mixed wastewater after biochemical enhancement treatment in step (2), and multi-stage synergistic physicochemical treatment of the separated supernatant, which includes high-density sedimentation treatment, multi-media filtration treatment and ozone catalytic oxidation treatment in sequence.

[0011] Preferably, in step (1), the flocculation and adsorption treatment includes mixing the anthraquinone dye wastewater with a coagulant and a coagulant aid, adjusting the pH, and stirring the reaction.

[0012] The filter press dewatering treatment includes using a filter press to dewater the wastewater after flocculation and adsorption treatment;

[0013] The ozone catalytic oxidation treatment includes: introducing O3 into the wastewater after pressure filtration and dewatering in the presence of a catalyst to carry out a catalytic oxidation reaction.

[0014] Preferably, in step (1), the pretreatment of the azo pigment-free lake-type wastewater includes dissolved air flotation treatment;

[0015] The pretreatment of the azo pigment-containing lake-type wastewater includes coagulation and sedimentation treatment.

[0016] Preferably, in step (2), the other wastewater in the factory area includes at least one of the following: floor washing water in the dye workshop, production wastewater in the pigment workshop, initial rainwater in the factory area, and domestic sewage.

[0017] Preferably, in step (2), the hydrolysis acidification treatment includes: mixing the mixed wastewater with salt-tolerant hydrolytic bacteria and acid-producing bacteria under anaerobic conditions, and adding phosphorus nutrients during the hydrolysis acidification treatment process, using the salt-tolerant hydrolytic bacteria and acid-producing bacteria to convert the residual complex organic matter in the wastewater into small molecule organic acids.

[0018] Preferably, in step (2), the anoxic treatment includes: adding facultative denitrifying bacteria to the wastewater under anoxic conditions, using the facultative denitrifying bacteria to denitrify the reflux nitrified liquid from the aerobic treatment process, and using the organic matter in the wastewater as the carbon source for denitrification by the denitrifying bacteria to reduce nitrate and nitrite to nitrogen.

[0019] The aerobic treatment is a three-stage moving bed biofilm reaction treatment, which includes: adding suspended biological packing material to the wastewater, using the suspended biological packing material for aerobic treatment, and then recirculating the nitrified liquid from the aerobic treatment to the anoxic treatment process.

[0020] Preferably, in step (3), the high-density sedimentation treatment includes mixing treatment, flocculation treatment and clarification treatment, to flocculate and decolorize the wastewater;

[0021] The multi-media filtration process includes: wastewater flowing through filter media, where suspended particles in the wastewater are trapped by the filter media, thus removing suspended solids;

[0022] The ozone catalytic oxidation treatment includes: in the presence of a catalyst, wastewater undergoes a three-phase contact reaction with ozone to further remove COD and color in order to meet emission standards.

[0023] On the other hand, the present invention also provides a multi-stage synergistic anthraquinone dye wastewater treatment system, the system comprising: an anthraquinone dye wastewater equalization tank, a flocculation adsorption reaction tank, an anthraquinone plate and frame filter press, an anthraquinone ozone catalytic oxidation tank, a comprehensive equalization tank, a hydrolysis acidification tank, an acidification sedimentation tank, an anoxic tank, an aerobic tank, a secondary sedimentation tank, an intermediate water tank, a high-density sedimentation tank, a multi-media filtration tank, an ozone catalytic oxidation tank, an ozone stripping tank, and an external discharge monitoring tank, wherein the aerobic tank is a moving bed biofilm reaction tank;

[0024] It also includes a regulating tank for azo pigment-free lake-type wastewater and a dissolved air flotation tank connected in sequence, wherein the outlet of the dissolved air flotation tank is connected to the inlet of the integrated regulating tank;

[0025] It also includes an equalization tank and a coagulation sedimentation tank for azo pigment lake-type wastewater, which are connected in sequence, with the outlet of the coagulation sedimentation tank connected to the inlet of the equalization tank.

[0026] Preferably, the moving bed biofilm reactor is a three-stage moving bed biofilm reactor, comprising three moving bed biofilm reactors connected in series. Each moving bed biofilm reactor is equipped with a nitrification liquor return port, which is connected to the anoxic tank.

[0027] Preferably, the system further includes a sludge dewatering device, the inlet of which is connected to the sludge outlet of the dissolved air flotation tank, the sludge outlet of the coagulation sedimentation tank, the sludge outlet of the acidification sedimentation tank, the sludge outlet of the secondary sedimentation tank, and the sludge outlet of the high-density sedimentation tank.

[0028] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0029] 1. This invention pre-treats anthraquinone dye wastewater through targeted flocculation adsorption, pressure filtration dewatering, and ozone catalytic oxidation, thereby separating and destroying anthraquinone groups, reducing their biotoxicity, eliminating the impact on the biochemical treatment system, and improving the wastewater properties, making it easier for further biochemical treatment.

[0030] 2. This invention improves COD removal rate and enhances nitrification and decolorization effects through the multi-stage synergistic effect of pretreatment, biochemical enhancement treatment, and physicochemical synergistic treatment.

[0031] 3. This invention enhances biochemical treatment through a three-stage moving bed biofilm reactor (MBBR). The nitrifying bacteria, which are most susceptible to shock in the biological phase, attach to the suspended packing material, thus strengthening their shock resistance and reducing the risk of loss of traditional activated sludge after shock. The three-stage moving bed biofilm reactor separates the functions of COD degradation and nitrification, solving the competition between nitrifying bacteria and heterotrophic bacteria, resulting in better nitrification.

[0032] 4. Through physicochemical synergistic treatment, the biologically recalcitrant and non-degradable organic matter after biochemical treatment is further removed, and chromogenic groups are removed, ensuring that COD and color emissions meet standards.

[0033] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0034] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0035] Figure 1This is a flow chart of the multi-stage synergistic process for treating anthraquinone-containing dye wastewater according to the present invention.

[0036] Figure 2 This is a graph showing the COD data of anthraquinone dye wastewater pretreatment in Example 2;

[0037] Figure 3 This is a graph showing the NH3-N and TN data for the pretreatment of anthraquinone dye wastewater in Example 2;

[0038] Figure 4 This is a graph showing the pretreatment data of azo pigment-free lake-based wastewater in Example 2;

[0039] Figure 5 This is a graph showing the pretreatment data of azo pigment-containing lake wastewater in Example 2;

[0040] Figure 6 This is a graph showing COD data from the integrated wastewater biochemical enhancement and physicochemical synergistic treatment in Example 2;

[0041] Figure 7 This is a data graph of NH3-N from the integrated wastewater biochemical enhancement and physicochemical synergistic treatment in Example 2;

[0042] Figure 8 This is a TN data graph for the integrated wastewater biochemical enhancement and physicochemical synergistic treatment in Example 2;

[0043] Figure 9 This is a colorimetric data graph of the integrated wastewater biochemical enhancement and physicochemical synergistic treatment in Example 2.

[0044] Figure label:

[0045] 101-Anthraquinone dye wastewater equalization tank; 102-Flocculation and adsorption reaction tank; 103-Anthraquinone plate and frame filter press; 104-Anthraquinone ozone catalytic oxidation tank; 105-Azo pigment non-lake wastewater equalization tank; 106-Dissolved air flotation tank; 107-Azo pigment lake-containing wastewater equalization tank; 108-Coagulation sedimentation tank; 109-Comprehensive equalization tank; 201-Hydrolysis acidification tank; 202-Acidification sedimentation tank; 203-Anoxic tank; 204-Aerobic tank; 205-Secondary sedimentation tank; 206-Intermediate water tank; 301-High-density sedimentation tank; 302-Multi-media filtration tank; 303-Ozone catalytic oxidation tank; 304-Ozone stripping tank; 305-External discharge monitoring tank; 401-Sludge dewatering device. Detailed Implementation

[0046] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0047] On one hand, the present invention provides a method for treating anthraquinone-containing dye wastewater based on multi-stage synergistic treatment, the method comprising:

[0048] Step (1) Pre-treats the anthraquinone dye wastewater, the azo pigment non-lake wastewater, and the azo pigment lake wastewater respectively. The pre-treatment of the anthraquinone dye wastewater includes sequential flocculation adsorption treatment, pressure filtration dewatering treatment, and ozone catalytic oxidation treatment.

[0049] Step (2) involves mixing the anthraquinone dye wastewater, azo pigment non-lake wastewater, and azo pigment lake wastewater that have undergone pretreatment in step (1) with other wastewater from the plant area, and subjecting the resulting mixed wastewater to multi-stage synergistic biochemical enhancement treatment. The biochemical enhancement treatment includes sequential hydrolysis acidification treatment, anoxic treatment, and aerobic treatment, wherein the aerobic treatment is a moving bed biofilm reaction treatment.

[0050] Step (3) involves sedimentation and mud-water separation of the mixed wastewater after biochemical enhancement treatment in step (2), and multi-stage synergistic physicochemical treatment of the separated supernatant, which includes high-density sedimentation treatment, multi-media filtration treatment and ozone catalytic oxidation treatment in sequence.

[0051] Compared with existing technologies, the method provided by this invention targets anthraquinone dye wastewater through flocculation adsorption, pressure filtration dewatering, and ozone catalytic oxidation pretreatment. This separates and destroys anthraquinone groups, reduces their biotoxicity, eliminates the impact on the biological treatment system, and improves the wastewater properties, making it easier for further biological treatment. Through the multi-stage synergistic effect of pretreatment, biochemical enhancement treatment, and physicochemical co-treatment, the COD removal rate, nitrification denitrification, and decolorization effects are improved. Furthermore, since anthraquinone dye wastewater has a high salinity, mixing it with azo pigment wastewater after pretreatment can control the salinity, followed by comprehensive bio-enhanced and advanced treatment to meet discharge standards.

[0052] Specifically, in step (1), the flocculation and adsorption treatment includes mixing the anthraquinone dye wastewater with a coagulant and a coagulant aid, adjusting the pH, stirring the reaction, and flocculating and decolorizing the wastewater.

[0053] For example, coagulants used for the pretreatment of anthraquinone dye wastewater include ferrous sulfate and polyferric sulfate.

[0054] For example, the concentration of ferrous sulfate is 0.8-1.5 wt%, and the concentration of polyferric sulfate is 0.8-1.5 wt%.

[0055] For example, the coagulant used for the pretreatment of anthraquinone dye wastewater includes anionic PAM at a concentration of 20–40 ppm.

[0056] For example, adjusting the pH means controlling the pH at 8.1-8.3 and stirring the reaction for 15-20 minutes.

[0057] For example, in step (1), the filter press dewatering process includes using a filter press to dewater the wastewater after flocculation and adsorption treatment.

[0058] For example, the ozone catalytic oxidation treatment includes: introducing O3 into the wastewater after pressure filtration and dewatering in the presence of a catalyst to carry out a catalytic oxidation reaction.

[0059] For example, the catalyst used for ozone catalytic oxidation treatment is columnar activated carbon loaded with a noble metal; the noble metal is at least one selected from iron oxide, copper oxide, nickel oxide and manganese oxide.

[0060] For example, the contact reaction time of the catalyst is 0.5-1.5 h.

[0061] For example, in step (1), the pretreatment of the azo pigment-free lake-type wastewater includes dissolved air flotation treatment.

[0062] For example, the dissolved air flotation treatment includes: mixing azo pigment-free lake-based wastewater with a coagulant, pressurizing the dissolved air water to release a large number of microbubbles, and then having hydrocarbons and suspended solids come into contact with and adhere to the microbubbles before floating to the surface to form scum. The scum is scraped away, and the bottom part is the pretreated azo pigment-free lake-based wastewater.

[0063] For example, the coagulant used for the pretreatment of azo pigment-free lake-based wastewater is polyferric sulfate, with a dosage of 50-150 mg / L and a dissolved gas pressure of 0.45-0.5 MPa.

[0064] For example, in step (1), the pretreatment of the azo pigment lake-type wastewater includes coagulation and sedimentation treatment.

[0065] For example, the coagulation and sedimentation treatment includes a mixing reaction treatment, a flocculation reaction treatment and a sedimentation reaction treatment performed in sequence. A coagulant is added in the mixing reaction treatment, a hardening agent is added in the flocculation reaction treatment and a coagulant aid is added in the sedimentation reaction treatment, so that calcium ions and barium ions in the wastewater are converted into calcium carbonate and barium carbonate precipitates and then settle.

[0066] For example, the coagulant used for coagulation and sedimentation treatment is polyferric sulfate, the hardening agent is sodium carbonate, the coagulant aid is anionic PAM, the reaction pH is 10-10.3, and the reaction time is 15-20 min.

[0067] For example, in step (2), the other wastewater in the factory area includes at least one of the following: floor washing water in the dye workshop, production wastewater in the pigment workshop, initial rainwater in the factory area, and domestic sewage.

[0068] For example, the microorganisms in the hydrolysis acidification treatment, anoxic treatment and aerobic treatment are acclimatized to high salt and can tolerate salt ion concentrations of 14,000-16,000 mg / L.

[0069] For example, in step (2), the hydrolysis acidification treatment includes: mixing the mixed wastewater with salt-tolerant hydrolytic bacteria and acid-producing bacteria under anaerobic conditions, and adding phosphorus nutrients as a phosphorus source during the hydrolysis acidification treatment process. The salt-tolerant hydrolytic bacteria and acid-producing bacteria under anaerobic conditions convert the residual complex organic matter in the wastewater into small molecule organic acids (such as acetic acid, propionic acid, etc.), thereby improving the biodegradability of the wastewater (B / C ratio is increased to 0.3-0.5).

[0070] For example, the conditions for the hydrolysis acidification treatment include: pH 6.8-7.5 and hydrolysis acidification ORP of -250 to -100 mV.

[0071] For example, in step (2), the anoxic treatment includes: under anoxic conditions, adding facultative denitrifying bacteria to the wastewater, using the facultative denitrifying bacteria to denitrify the reflux nitrified liquid from the aerobic treatment process, and using the organic matter in the wastewater as a carbon source for the denitrifying bacteria to reduce nitrate and nitrite to nitrogen. When the organic matter in the wastewater is insufficient, the carbon source is supplemented.

[0072] For example, the ORP during hypoxia treatment is controlled between -200 and -50 mV.

[0073] For example, the aerobic treatment is a three-stage moving bed biofilm reactor treatment. This treatment includes: adding suspended biological packing material to the wastewater for aerobic treatment; and recirculating the nitrified liquid from the aerobic treatment to the anoxic treatment process. The first and second stages of the moving bed biofilm reactor treatment enhance the decomposition of recalcitrant COD, while the third stage enhances NH3-N nitrification and simultaneously supplements the alkalinity required for the nitrification reaction. The three-stage moving bed biofilm reactor treatment decomposes recalcitrant COD into CO2 and H2O, oxidizes NH3-N into NO2-N and NO3-N, and then recirculates the nitrified liquid to the anoxic treatment process for further nitrogen removal.

[0074] For example, the suspended biological packing material in the moving bed biofilm reaction treatment has a filling rate of 35-40% and a specific surface area of ​​500-800 m². 2 / m 3 The packing diameter is 25±2mm, the packing length is 3-10mm, and the material is PE.

[0075] For example, the pH of the moving bed biofilm reaction treatment is 7.2-8.2, the DO of the first and second stage moving bed biofilm reaction treatments is controlled at 2-2.5, and the DO of the third stage moving bed biofilm reaction treatment is controlled at 3-4.

[0076] For example, in step (3), the high-density sedimentation treatment includes mixing treatment, flocculation treatment and clarification treatment to flocculate and decolorize the wastewater.

[0077] For example, the mixing treatment includes mixing wastewater and coagulant; the flocculation treatment includes hydrolysis of the coagulant followed by a flocculation reaction; and the clarification treatment includes sedimentation and clarification of the wastewater after the flocculation reaction.

[0078] For example, the coagulant in the high-density precipitation treatment is polyferric sulfate, with a dosage of 500-800 mg / L, the reaction pH is controlled at 7.2-8.2, and the reaction time is 15-25 min.

[0079] For example, in step (3), the multi-media filtration process includes: wastewater flowing through filter media, and suspended particles in the wastewater being intercepted by the filter media to remove suspended solids.

[0080] For example, the filter media includes anthracite and quartz sand, with the anthracite filling height being 500-800 mm and the quartz sand filling height being 300-400 mm.

[0081] For example, in step (3), the ozone catalytic oxidation treatment includes: in the presence of a catalyst, wastewater undergoes a three-phase contact reaction with ozone and the catalyst to further remove COD and color in order to meet emission standards.

[0082] For example, in step (3), the catalyst used in the ozone catalytic oxidation treatment is columnar activated carbon loaded with noble metals, and the catalyst contact reaction time is 1.5-2 hours. The noble metal is at least one of iron oxide, copper oxide, nickel oxide, and manganese oxide.

[0083] For example, the method further includes: passing compressed air into the wastewater after ozone catalytic oxidation treatment in step (3) for purging, so that the residual ozone in the wastewater is carried out and destroyed by the air before being discharged.

[0084] Secondly, the present invention also provides a multi-stage synergistic system for treating anthraquinone-containing dye wastewater, such as... Figure 1As shown, the system includes, in sequence, an anthraquinone dye wastewater equalization tank 101, a flocculation and adsorption reaction tank 102, an anthraquinone plate and frame filter press 103, an anthraquinone ozone catalytic oxidation tank 104, a comprehensive equalization tank 109, a hydrolysis acidification tank 201, an acidification sedimentation tank 202, an anoxic tank 203, an aerobic tank 204, a secondary sedimentation tank 205, an intermediate water tank 206, a high-density sedimentation tank 301, a multi-media filter 302, an ozone catalytic oxidation tank 303, and an ozone stripping tank 30. 4. An external discharge monitoring tank 305; the aerobic tank 204 is a moving bed biofilm reactor; it also includes a series of interconnected azo pigment lake-free wastewater conditioning tank 105 and dissolved air flotation tank 106, the outlet of the dissolved air flotation tank 106 being connected to the inlet of the integrated conditioning tank 109; it also includes a series of interconnected azo pigment lake-containing wastewater conditioning tank 107 and coagulation sedimentation tank 108, the outlet of the coagulation sedimentation tank 108 being connected to the inlet of the integrated conditioning tank 109.

[0085] For example, the moving bed biofilm reactor is a three-stage moving bed biofilm reactor, comprising three moving bed biofilm reactors connected in series. Each moving bed biofilm reactor is equipped with a nitrification liquid return port, which is connected to the anoxic tank 203.

[0086] For example, the system further includes a sludge dewatering device 401, the inlet of which is connected to the sludge outlet of the dissolved air flotation tank 106, the sludge outlet of the coagulation sedimentation tank 108, the sludge outlet of the acidification sedimentation tank 202, the sludge outlet of the secondary sedimentation tank 205, and the sludge outlet of the high-density sedimentation tank 301.

[0087] The method for treating anthraquinone dye wastewater using the above-mentioned multi-stage synergistic anthraquinone-containing dye wastewater treatment system includes:

[0088] (a) Anthraquinone dye wastewater is collected separately in an anthraquinone dye wastewater equalization tank 101. The wastewater is pumped to a flocculation adsorption reaction tank 102. Coagulants and coagulant aids are added to the flocculation adsorption reaction tank 102 in sequence. After mixing and reacting under mechanical stirring, a mixture of sludge and wastewater is obtained. The mixture is pumped under pressure to an anthraquinone plate and frame filter press 103. The sludge is retained by the anthraquinone plate and frame filter press 103. The wastewater, as the filtrate after filtration, flows by gravity to an anthraquinone ozone catalytic oxidation tank 104. Ozone is introduced into the anthraquinone ozone catalytic oxidation tank 104, and a three-phase catalytic oxidation reaction occurs under the action of a catalyst.

[0089] (b) The azo pigment non-lake wastewater is collected separately into the azo pigment non-lake wastewater equalization tank 105, and pumped to the dissolved air flotation tank 106. Coagulant is added to the dissolved air flotation tank 106 for stirring and reaction. A dissolved air release tank is set at the outlet of the dissolved air flotation tank 106. The pressurized dissolved air water releases a large number of microbubbles in the tank. Hydrocarbons and suspended solids in the wastewater come into contact with and adhere to the microbubbles and float to the surface of the tank to form scum. The scum is scraped away, and the pretreated wastewater at the bottom of the tank flows by gravity to the comprehensive equalization tank 109.

[0090] (c) The azo pigment lake-containing wastewater is collected separately into the azo pigment lake-containing wastewater equalization tank 107. The wastewater is pumped to the coagulation sedimentation tank 108 and passes through the mixing reaction tank, flocculation tank and sedimentation tank in sequence. Coagulant, hardening agent and coagulant aid are added in sequence. The calcium ions and barium ions in the wastewater are converted into calcium carbonate and barium carbonate precipitates and settle in the sedimentation tank. The supernatant is the purified wastewater and flows by gravity to the comprehensive equalization tank 109.

[0091] (d) The pre-treated wastewater is mixed evenly with other wastewater from the plant area in the integrated equalization tank 109. The effluent from the integrated equalization tank 109 is pumped to the hydrolysis acidification tank 201. Under anaerobic conditions, salt-tolerant hydrolytic bacteria and acid-producing bacteria convert the residual complex organic matter in the wastewater into small-molecule organic acids (acetic acid, propionic acid, etc.), improving the biodegradability of the wastewater (B / C ratio increased to 0.3-0.5). A phosphorus source is added at the inlet of the hydrolysis acidification treatment to maintain the microorganisms' phosphorus requirements. The outlet of the hydrolysis acidification tank 201 is connected to the acidification sedimentation tank 202. After sedimentation in the acidification sedimentation tank 202, a portion of the acidified sludge is pumped back to the inlet of the hydrolysis acidification tank 201, and the supernatant flows by gravity to the anoxic tank 203. Facultative denitrifying bacteria denitrify the returned nitrified liquid, removing nitrate (NO3) ions. - ), nitrite (NO2) -The organic matter in the wastewater is reduced to nitrogen (N2). Anoxic tank 203 is equipped with a mechanical mixer and an external carbon source addition point to supplement carbon when the organic matter in the wastewater is insufficient. The outlet of anoxic tank 203 is connected to aerobic tank 204 (moving bed biofilm reactor (MBBR)). Aerobic treatment is carried out using suspended biological packing. The moving bed biofilm reactor is divided into three stages: the first and second stages are for enhanced decomposition of recalcitrant COD, and the third stage is for enhanced NH3-N nitrification. The alkalinity required for nitrification is supplemented at the inlet of the third-stage moving bed biofilm reactor. The moving bed biofilm reactor (MBBR) decomposes recalcitrant COD into CO2 and H2O, and oxidizes NH3-N into NO2-N and NO3-N. The nitrified liquid is then returned to anoxic tank 203 for further denitrification. The outlet of the moving bed biofilm reactor (MBBR) is connected to the secondary sedimentation tank 205. The mixture of sludge and wastewater is separated in the secondary sedimentation tank. A portion of the sludge is pumped back to the inlet of the anoxic tank 203. The supernatant of the secondary sedimentation tank 205 flows by gravity to the intermediate water tank 206. The hydrolysis acidification tank 201, acidification sedimentation tank 202, anoxic tank 203, moving bed biofilm reactor (MBBR), secondary sedimentation tank 205 and intermediate water tank 206 constitute the multi-stage synergistic biochemical enhancement treatment system of this invention.

[0092] (e) Wastewater from intermediate pool 206 is pumped to high-density sedimentation tank 301, where it passes sequentially through mixing tank, flocculation tank, and clarification tank. Coagulant is added to the flocculation tank for flocculation and decolorization. The supernatant from the clarification tank flows by gravity to multi-media filtration tank 302, where suspended particles are removed by the filter media. The filtered effluent flows by gravity to ozone catalytic oxidation tank 303, where a catalyst is filled. Wastewater, catalyst, and ozone undergo a three-phase contact reaction to remove residual COD and color. The outlet of ozone catalytic oxidation tank 303 is connected to ozone stripping tank 304. Compressed air is introduced into ozone stripping tank 304 to purge the wastewater, causing residual ozone in the wastewater to be carried out and destroyed by the air before discharge. The wastewater then flows by gravity to discharge monitoring tank 305 for final discharge. The high-density sedimentation tank 301, multi-media filtration tank 302, ozone catalytic oxidation tank 303, ozone stripping tank 304, and discharge monitoring tank 305 constitute the multi-stage synergistic physicochemical treatment system of this invention.

[0093] In addition, the sludge in the dissolved air flotation tank 106, the sludge in the coagulation sedimentation tank 108, the sludge that was not returned in the acidification sedimentation tank 202, the sludge that was not returned in the secondary sedimentation tank 205, and the sludge in the high-density sedimentation tank 301 are fed into the sludge dewatering device 401 for treatment and then transported off-site for disposal.

[0094] In one embodiment, the total influent flow rate of the pretreated equalization tank is 800-1000 m³ / h. 3 / d, the pretreated wastewater, after treatment in the comprehensive equalization tank 109, has the following water quality: TDS 13000±2000mg / L, pH 6.5-7.8, COD 2700-4600mg / L, NH3-N 22-138mg / L, TN 45-189mg / L, and color 3000-5000 times. The wastewater quality fluctuates considerably. The effluent quality after treatment by the method and system of this invention is: pH 6-9, COD ≤300mg / L, NH3-N ≤30mg / L, TN ≤50mg / L, and color ≤100 times, meeting the discharge standards.

[0095] Based on a summary of the advantages and disadvantages of existing methods for treating anthraquinone wastewater, this invention proposes a multi-stage synergistic treatment method. Specifically, it includes: flocculation and sedimentation, ozone catalytic oxidation, bio-enhanced treatment, and advanced treatment.

[0096] First, coagulants and flocculants are added to the wastewater. After coagulation and flocculation, destabilization, adsorption (the colloids formed by the coagulants have a certain adsorption capacity), and pressure filtration are completed to remove colloidal suspended organic matter from the anthraquinone wastewater. The filtrate after pressure filtration mainly contains dissolved pollutants. The sludge after pressure filtration is disposed of together with other sludge. The coagulants and flocculants used are all conventional reagents. This method avoids the problem of difficult regeneration of adsorption materials.

[0097] Secondly, the anthraquinone dissolved COD and color of the filtrate produced in the previous step undergo advanced oxidation reactions of hydroxyl radicals with ozone gas in the presence of a catalyst. This destroys the organic molecular structure in the wastewater, breaks down toxic groups, and eliminates the biotoxicity of the wastewater. Since ozone catalytic oxidation is carried out under weakly alkaline conditions, the ozone gas decomposes into oxygen and is then discharged. Therefore, this method avoids the acid and alkali adjustments, salt introduction, and large amounts of sludge generated by Fenton and Fenton-like processes.

[0098] Furthermore, after ozone catalytic oxidation to detoxify anthraquinone wastewater, further treatment with hydrolysis acidification and biofilm enhancement removes COD, NH3-N, and TN. This method does not require specially screened microbial strains; the sludge microbial strains can be inoculated from nearby industrial wastewater treatment plants, making them inexpensive and readily available, resulting in low overall costs.

[0099] Finally, after deep treatment to remove the remaining small amount of recalcitrant COD, the emission standards are met.

[0100] The following specific embodiments further illustrate the multi-level synergistic method and system for treating anthraquinone-containing dye wastewater of the present invention.

[0101] Example 1

[0102] This embodiment provides a multi-stage synergistic treatment system for anthraquinone-containing dye wastewater, comprising: an anthraquinone dye wastewater equalization tank 101, a flocculation and adsorption reaction tank 102, an anthraquinone plate and frame filter press 103, an anthraquinone ozone catalytic oxidation tank 104, a comprehensive equalization tank 109, a hydrolysis acidification tank 201, an acidification sedimentation tank 202, an anoxic tank 203, an aerobic tank 204, a secondary sedimentation tank 205, an intermediate water tank 206, a high-density sedimentation tank 301, a multi-media filter 302, and an ozone catalytic oxidation tank, all connected in sequence. 303, ozone stripping tank 304, and discharge monitoring tank 305; the aerobic tank 204 is a moving bed biofilm reactor; it also includes a series-connected azo pigment lake-free wastewater conditioning tank 105 and dissolved air flotation tank 106, the outlet of the dissolved air flotation tank 106 being connected to the inlet of the integrated conditioning tank 109; it also includes a series-connected azo pigment lake-containing wastewater conditioning tank 107 and coagulation sedimentation tank 108, the outlet of the coagulation sedimentation tank 108 being connected to the inlet of the integrated conditioning tank 109. The moving bed biofilm reactor is a three-stage moving bed biofilm reactor, including three moving bed biofilm reactors connected in series, each moving bed biofilm reactor being equipped with a nitrification liquor return port, which is connected to the anoxic tank 203. The system also includes a sludge dewatering device 401, the inlet of which is connected to the sludge outlet of the dissolved air flotation tank 106, the sludge outlet of the coagulation sedimentation tank 108, the sludge outlet of the acidification sedimentation tank 202, the sludge outlet of the secondary sedimentation tank 205, and the sludge outlet of the high-density sedimentation tank 301.

[0103] Example 2

[0104] This embodiment provides a multi-stage synergistic method for treating anthraquinone-containing dye and pigment wastewater, employing the multi-stage synergistic anthraquinone-containing dye and pigment wastewater treatment system of Example 1. The method includes:

[0105] (a) Anthraquinone dye wastewater is collected separately into an anthraquinone dye wastewater equalization tank 101. The wastewater is pumped to a flocculation adsorption reaction tank 102. Coagulants and coagulant aids are added to the flocculation adsorption reaction tank 102 in sequence. The coagulants include ferrous sulfate and polyferric sulfate. The concentration of ferrous sulfate is 1.2 wt%, the concentration of polyferric sulfate is 1.2 wt%, and the coagulant aid includes anionic PAM at a concentration of 30 ppm. The mixture was stirred under mechanical agitation, with the pH controlled at 8.2 and the stirring time at 20 min, resulting in a mixture of sludge and wastewater. This mixture was then pumped under pressure to an anthraquinone plate and frame filter press 103. The sludge was retained by the anthraquinone plate and frame filter press 103, while the wastewater, as the filtrate after filtration, flowed by gravity to the anthraquinone ozone catalytic oxidation tank 104. Ozone was introduced into the anthraquinone ozone catalytic oxidation tank 104, where a three-phase catalytic oxidation reaction occurred under the action of a catalyst. The catalyst was columnar activated carbon loaded with iron oxide, copper oxide, nickel oxide, and manganese oxide, and the contact reaction time was 1 h.

[0106] (b) The azo pigment non-lake wastewater is collected separately into the azo pigment non-lake wastewater equalization tank 105, and pumped to the dissolved air flotation tank 106. A coagulant is added to the dissolved air flotation tank 106 for stirring and reaction. The coagulant is polyferric sulfate, with a concentration of 100 mg / L and a dissolved air pressure of 0.5 MPa. A dissolved air release tank is set at the outlet of the dissolved air flotation tank 106. The pressurized dissolved air water releases a large number of microbubbles in the tank. Hydrocarbons and suspended solids in the wastewater come into contact with and adhere to the microbubbles and float to the surface of the tank to form scum. The scum is scraped away, and the pretreated wastewater at the bottom of the tank flows by gravity to the comprehensive equalization tank 109.

[0107] (c) The azo pigment lake-containing wastewater is collected separately into the azo pigment lake-containing wastewater equalization tank 107. The wastewater is pumped to the coagulation sedimentation tank 108 and passes through the mixing reaction tank, flocculation tank and sedimentation tank in sequence. Coagulant, hardening agent and coagulant aid are added in sequence. The coagulant is polyferric sulfate, the hardening agent is sodium carbonate and the coagulant aid is anionic PAM. The reaction pH is 10.2 and the reaction time is 20 min. The calcium ions and barium ions in the wastewater are converted into calcium carbonate and barium carbonate precipitates and settle in the sedimentation tank. The supernatant is the purified wastewater and flows by gravity to the comprehensive equalization tank 109.

[0108] (d) The pretreated wastewater is mixed evenly with other wastewater from the plant area in the integrated equalization tank 109. The effluent from the integrated equalization tank 109 is pumped to the hydrolysis acidification tank 201. The hydrolysis acidification conditions include: pH 7.2, hydrolysis acidification ORP -200mV. Salt-tolerant hydrolytic bacteria and acid-producing bacteria under anaerobic conditions convert residual complex organic matter in the wastewater into small-molecule organic acids (acetic acid, propionic acid, etc.). A phosphorus source is added at the inlet of the hydrolysis acidification tank to maintain the microorganisms' phosphorus requirements. The outlet of the hydrolysis acidification tank 201 is connected to the acidification sedimentation tank 202. After sedimentation in the acidification sedimentation tank 202, a portion of the acidified sludge is pumped back to the inlet of the hydrolysis acidification tank 201, and the supernatant flows by gravity to the anoxic tank 203. The anoxic treatment ORP is -150mV. Facultative denitrifying bacteria are used to denitrify the returned nitrified liquid, removing nitrate (NO3) ions. - ), nitrite (NO2) - The wastewater is reduced to nitrogen (N2). Anoxic tank 203 is equipped with a mechanical stirrer and an external carbon source addition point to supplement carbon when organic matter in the wastewater is insufficient. The outlet of anoxic tank 203 connects to aerobic tank 204 (moving bed biofilm reactor (MBBR)). Aerobic treatment is performed using suspended biological packing. The moving bed biofilm reactor is divided into three stages: the first and second stages enhance the decomposition of recalcitrant COD, and the third stage enhances NH3-N nitrification. The alkalinity required for nitrification is supplemented at the inlet of the third-stage moving bed biofilm reactor. The moving bed biofilm reactor (MBBR) decomposes recalcitrant COD into CO2 and H2O, and oxidizes NH3-N into NO2-N and NO3-N. The nitrified liquid is then returned to anoxic tank 203 for further denitrification. The suspended biological packing in the moving bed biofilm reactor has a filling rate of 37% and a specific surface area of ​​700 m². 2 / m 3 The packing material has a diameter of 25mm and a length of 7mm, and is made of PE. The pH of the moving bed biofilm reactor is 8. The dissolved oxygen (DO) in the first and second stages of the moving bed biofilm reactor is 2.2, and the DO in the third stage is controlled at 3. The outlet of the moving bed biofilm reactor (MBBR) is connected to the secondary sedimentation tank 205. The mixture of sludge and wastewater is separated in the secondary sedimentation tank 205. A portion of the sludge is pumped back to the inlet of the anoxic tank 203, and the supernatant from the secondary sedimentation tank 205 flows by gravity to the intermediate water tank 206. The microorganisms in the hydrolysis acidification tank, anoxic tank, and aerobic tank have been acclimated to high salt concentrations and can tolerate a salt ion concentration of 15000mg / L.

[0109] (e) Wastewater from intermediate pool 206 is pumped to high-density sedimentation tank 301, where it sequentially passes through a mixing tank, flocculation tank, and clarification tank. A coagulant, polyferric sulfate (700 mg / L), is added to the flocculation tank for flocculation and decolorization. The reaction pH is controlled at 7.8, and the reaction time is 20 min. The supernatant from the clarification tank flows by gravity to multi-media filter tank 302. Suspended particles are removed by the filter media in multi-media filter tank 302, which includes anthracite and quartz sand. The anthracite filling height is 700 mm, and the quartz sand filling height is 350 mm. The filtered effluent flows by gravity to ozone catalytic oxidation tank 303, which is filled with a catalyst. The catalyst is columnar activated carbon loaded with iron oxide, copper oxide, nickel oxide, and manganese oxide. The wastewater, catalyst, and ozone undergo a three-phase contact reaction for 2 hours to remove residual COD and color. The outlet of ozone catalytic oxidation tank 303 is connected to ozone stripping tank 304. Compressed air is introduced into ozone stripping tank 304 to purge wastewater. Residual ozone in the wastewater is carried out and destroyed by the air before being discharged. The wastewater flows by gravity to discharge monitoring tank 305 for external discharge. Sludge from dissolved air flotation tank 106, sludge from coagulation sedimentation tank 108, non-returned sludge from acidification sedimentation tank 202, non-returned sludge from secondary sedimentation tank 205, and sludge from high-density sedimentation tank 301 are treated in sludge dewatering device 401 and then transported for disposal.

[0110] The influent and effluent water quality after a two-month operation period according to the method in Example 2 are as follows: Figures 2-9 The following information is listed in Table 1:

[0111] Table 1. Water Quality Data for Example 2

[0112]

[0113]

[0114] Comparative Example 1

[0115] This comparative example provides a method for treating anthraquinone dye wastewater similar to Example 2. The difference is that the pretreatment method for the anthraquinone dye wastewater is coagulation and sedimentation treatment. Specifically, sulfuric acid is added to the pH adjustment tank, coagulant PAC is added to the reaction tank, and coagulant aid PAM is added to the flocculation tank in sequence, and the reaction is stirred. The pH in the pH adjustment tank is controlled at 8, the concentration of coagulant PAC is 1.2 wt%, and the concentration of coagulant aid PAM is 30 ppm.

[0116] The influent and effluent water quality after two months of operation using the method described in Comparative Example 1 are shown in Table 2:

[0117] Table 2 Comparative Example 1 Operating Water Quality Data Table

[0118]

[0119]

[0120] A comparison of the data in Table 2 with those in Table 1 shows that the pretreatment method for anthraquinone dye wastewater of the present invention (including flocculation adsorption, pressure filtration dewatering, and ozone catalytic oxidation) can significantly improve the pretreatment effect of anthraquinone wastewater, reduce the toxicity and inhibition of anthraquinones, and enhance biodegradability.

[0121] Comparative Example 2

[0122] This comparative example employs a conventional method for treating anthraquinone-containing dye wastewater, including: pretreating the anthraquinone dye wastewater sequentially through an anthraquinone dye wastewater equalization tank, a Fenton acidification tank, a Fenton hydrogen peroxide reaction tank, a Fenton reduction tank, a Fenton flocculation tank, a Fenton sedimentation tank, and a Fenton effluent tank; pretreating azo pigment non-lake-containing wastewater and azo pigment lake-containing wastewater using the same method as in Example 2; and mixing the pretreated azo pigment non-lake-containing wastewater, azo pigment lake-containing wastewater, and Fenton pretreated anthraquinone dye wastewater sequentially into a comprehensive equalization tank, an anoxic tank, an aerobic activated sludge tank, a secondary sedimentation tank, an intermediate water tank, a coagulation sedimentation tank, a filtration tank, and an external discharge product water tank for further treatment.

[0123] The method used in Comparative Example 2 was run for 2 months, and the data are shown in Table 3.

[0124] Table 3 Comparative Example 2 Operating Water Quality Data Table

[0125]

[0126]

[0127] Table 4 shows the comparative data on chemical consumption, electricity consumption, and overall cost between Comparative Example 2 and Example 2:

[0128] Table 4. Cost comparison between Comparative Example 2 and Example 2

[0129]

[0130]

[0131] As can be seen from Tables 3 and 4 of Comparative Example 2 and Example 2, the anthraquinone wastewater pretreatment method of the present invention is superior to the existing Fenton pretreatment method in terms of pretreatment effect and overall cost.

[0132] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for treating anthraquinone-containing dye wastewater based on multi-stage synergistic treatment, characterized in that, The method includes: Step (1) Pre-treats the anthraquinone dye wastewater, the azo pigment non-lake wastewater, and the azo pigment lake wastewater respectively. The pre-treatment of the anthraquinone dye wastewater includes sequential flocculation adsorption treatment, pressure filtration dewatering treatment, and ozone catalytic oxidation treatment. The pretreatment of the azo pigment-free lake-type wastewater includes dissolved air flotation treatment; The pretreatment of the azo pigment-containing lake wastewater includes coagulation and sedimentation treatment; Step (2) involves mixing the anthraquinone dye wastewater, azo pigment lake-free wastewater, and azo pigment lake-containing wastewater that have been pretreated in step (1) with other wastewater from the plant area, and subjecting the resulting mixed wastewater to multi-stage synergistic biochemical enhancement treatment. The biochemical enhancement treatment includes sequential hydrolysis acidification treatment, anoxic treatment, and aerobic treatment. The aerobic treatment is a moving bed biofilm reaction treatment. Step (3) involves sedimentation and mud-water separation of the mixed wastewater after biochemical enhancement treatment in step (2), and multi-stage synergistic physicochemical treatment of the separated supernatant, which includes high-density sedimentation treatment, multi-media filtration treatment and ozone catalytic oxidation treatment in sequence.

2. The method for treating anthraquinone-containing dye wastewater based on multi-stage synergistic treatment according to claim 1, characterized in that, In step (1), the flocculation and adsorption treatment includes mixing the anthraquinone dye wastewater with a coagulant and a coagulant aid, adjusting the pH, and stirring the reaction. The filter press dewatering treatment includes using a filter press to dewater the wastewater after flocculation and adsorption treatment; The ozone catalytic oxidation treatment includes: introducing O3 into the wastewater after pressure filtration and dewatering in the presence of a catalyst to carry out a catalytic oxidation reaction.

3. The method for treating anthraquinone-containing dye wastewater based on multi-stage synergistic treatment according to claim 1, characterized in that, In step (2), the other wastewater in the factory area includes at least one of the following: floor washing water in the dye workshop, production wastewater in the pigment workshop, initial rainwater in the factory area, and domestic sewage.

4. The method for treating anthraquinone-containing dye wastewater based on multi-stage synergistic treatment according to claim 1, characterized in that, In step (2), the hydrolysis acidification treatment includes: mixing the mixed wastewater with salt-tolerant hydrolytic bacteria and acid-producing bacteria under anaerobic conditions, and adding phosphorus nutrients during the hydrolysis acidification treatment process, using the salt-tolerant hydrolytic bacteria and acid-producing bacteria to convert the residual complex organic matter in the wastewater into small molecule organic acids.

5. The method for treating anthraquinone-containing dye wastewater based on multi-stage synergistic treatment according to claim 1, characterized in that, In step (2), the anoxic treatment includes: under anoxic conditions, adding facultative denitrifying bacteria to the wastewater, using the facultative denitrifying bacteria to denitrify the reflux nitrified liquid from the aerobic treatment process, and using the organic matter in the wastewater as the carbon source for denitrification by the denitrifying bacteria to reduce nitrate and nitrite to nitrogen. The aerobic treatment is a three-stage moving bed biofilm reaction treatment, which includes: adding suspended biological packing material to the wastewater, using the suspended biological packing material for aerobic treatment, and then recirculating the nitrified liquid from the aerobic treatment to the anoxic treatment process.

6. The method for treating anthraquinone-containing dye wastewater based on multi-stage synergistic treatment according to claim 1, characterized in that, In step (3), the high-density sedimentation treatment includes mixing treatment, flocculation treatment and clarification treatment, which flocculate and decolorize the wastewater; The multi-media filtration process includes: wastewater flowing through filter media, where suspended particles in the wastewater are trapped by the filter media, thus removing suspended solids; The ozone catalytic oxidation treatment includes: in the presence of a catalyst, wastewater undergoes a three-phase contact reaction with ozone to further remove COD and color in order to meet emission standards.

7. A multi-stage synergistic system for treating anthraquinone-containing dye wastewater, characterized in that, The system comprises, in sequence, an anthraquinone dye wastewater equalization tank, a flocculation and adsorption reaction tank, an anthraquinone plate and frame filter press, an anthraquinone ozone catalytic oxidation tank, a comprehensive equalization tank, a hydrolysis and acidification tank, an acidification and sedimentation tank, an anoxic tank, an aerobic tank, a secondary sedimentation tank, an intermediate water tank, a high-density sedimentation tank, a multi-media filtration tank, an ozone catalytic oxidation tank, an ozone stripping tank, and an external discharge monitoring tank; the aerobic tank is a moving bed biofilm reaction tank. It also includes a regulating tank for azo pigment-free lake-type wastewater and a dissolved air flotation tank connected in sequence, wherein the outlet of the dissolved air flotation tank is connected to the inlet of the integrated regulating tank; It also includes an equalization tank and a coagulation sedimentation tank for azo pigment lake-type wastewater, which are connected in sequence, with the outlet of the coagulation sedimentation tank connected to the inlet of the equalization tank.

8. The multi-stage synergistic treatment system for anthraquinone-containing dye wastewater according to claim 7, characterized in that, The moving bed biofilm reactor is a three-stage moving bed biofilm reactor, comprising three moving bed biofilm reactors connected in series. Each moving bed biofilm reactor is equipped with a nitrification liquor return port, which is connected to the anoxic tank.

9. The multi-stage synergistic treatment system for anthraquinone-containing dye wastewater according to claim 7, characterized in that, The system also includes a sludge dewatering device, the inlet of which is connected to the sludge outlet of the dissolved air flotation tank, the sludge outlet of the coagulation sedimentation tank, the sludge outlet of the acidification sedimentation tank, the sludge outlet of the secondary sedimentation tank, and the sludge outlet of the high-density sedimentation tank.

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