Mixed dye wastewater treatment device based on coupling of bioelectrochemistry and moving bed bio-membrane reactor and working method of mixed dye wastewater treatment device

Abstract

The invention discloses a mixed dye wastewater treatment device based on bioelectrochemistry and moving bed bio-membrane reactor coupling and a working method thereof, belongs to the technical field of wastewater treatment, and particularly relates to the mixed dye wastewater treatment device based on bioelectrochemistry and moving bed bio-membrane reactor coupling and the working method thereof. The invention aims to solve the problems that the mixed dye wastewater has great harm in the ecological environment and is difficult to completely degrade. According to the invention, the BES module and the MBBR module are stacked and amplified, and a coupling process is constructed to realize deep degradation and mineralization treatment of mixed dyes in water. The method has the advantages of low cost, convenience in operation, high practicability and the like, and stage removal and gradient removal of the wastewater can be realized. Pollutant detoxification of wastewater is realized step by step in the stacked bioelectrochemical module, and the detoxified wastewater enters the stacked moving bed bio-membrane reactor module again for step-by-step aerobic deep mineralization, so that deep enhanced treatment of refractory wastewater is realized, and the purpose of efficiently removing pollutants is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and particularly relates to a hybrid dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor and its working method. Background Art

[0002] With the rapid development of industry, the harm of hybrid dye wastewater to the water environment has become increasingly prominent. Among them, azo dyes, as the main component accounting for more than 70% in hybrid dyes, bring great difficulties to degradation and mineralization due to the complex aromatic structure in the molecule and the difficult-to-break azo bond. After the degradation of such dyes, most of the products are aromatic amine compounds harmful to the human body. These substances will enter the ecosystem through various channels, poison the organisms in the water body, disrupt the ecological balance, and may ultimately endanger human health through the transmission of the food chain. Therefore, the in-depth mineralization and effective removal of hybrid dye wastewater have extremely important research significance and broad application prospects in ensuring water environment safety.

[0003] In the technical field of wastewater treatment, when using a single anaerobic or aerobic treatment technology to treat organic wastewater in the past, many problems have emerged. A long startup period means that it takes a long time from the equipment being put into use to achieving a stable treatment effect, which increases the time cost and economic cost to a certain extent. The complex operation requires high professional requirements for technicians and is not conducive to large-scale popularization and application. Moreover, for refractory organic substances, the removal rate is relatively low, unable to meet the increasingly strict environmental protection standards. The anaerobic-aerobic combined process gradually finds wide application in the field of treating refractory wastewater due to its strong pollutant degradation ability, environmental friendliness, and technical flexibility. It uses the anaerobic stage to decompose macromolecular organic substances into small molecules, improving the biodegradability of the wastewater, and then further oxidizes and decomposes the small molecule organic substances through the aerobic stage. However, in actual applications, the anaerobic-aerobic combined process still faces many challenges. The difficulty in scaling up the device means that it is difficult to expand the treatment scale according to actual needs, restricting its application in large-scale industrial wastewater treatment projects. In addition, during the anaerobic and aerobic operation processes, the degradation of pollutants is not thorough enough, resulting in a certain amount of harmful substances still remaining in the treated wastewater, and the complete purification of hybrid dye wastewater cannot be achieved. Summary of the Invention

[0004] The present invention provides a hybrid dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor and its working method to solve the problems that hybrid dye wastewater causes great harm to the ecological environment and is difficult to be completely degraded.

[0005] A hybrid dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor consists of a first water distributor, a second water distributor, a BES unit, and an MBBR unit. The first water distributor is arranged at the bottom of the BES unit and is connected to the BES unit; the second water distributor is arranged at the bottom of the MBBR unit and is connected to the MBBR unit; the wastewater inlet is arranged at the bottom of the first water distributor, and the treated water outlet is arranged at the upper part of the MBBR unit.

[0006] The BES unit is formed by connecting several BES modules in series in the vertical direction. The bottom of the BES module is provided with an inlet, and the upper part is provided with an outlet. The inlets and outlets of adjacent modules are connected through conduits. Adjacent modules are connected by flanges and sealed with silicone rubber rings.

[0007] The MBBR unit is formed by connecting several MBBR modules in series in the vertical direction. The bottom of the MBBR module is provided with an inlet, and the upper part is provided with an outlet. The inlets and outlets of adjacent modules are connected through conduits. Adjacent modules are connected by flanges and sealed with silicone rubber rings.

[0008] A working method of a hybrid dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor is carried out according to the following steps:

[0009] I. Before the device assembly, the BES modules are inoculated with activated sludge for domestication. The glucose solution with a concentration of 1000 mg / L is fed into the anode, and the mixed dye with a concentration of 200 mg / L -1 + glucose with a concentration of 1000 mg / L -1 -1 is fed into the cathode to achieve successful film formation on the anode and cathode. After stable operation for at least 10 days, the BES modules are assembled; the MBBR modules are inoculated with aerobic activated sludge, and the glucose solution with a concentration of 1000 mg / L -1 is fed into the water. Through aeration domestication and cultivation, successful film formation on the biological fillers is achieved, and then the MBBR modules are assembled; then the BES-MBBR coupling device is assembled.

[0010] II. After the assembly is completed, the mixed dye wastewater first enters the BES unit through the first water distributor, flows through each BES module in the BES unit in sequence, and is sent from the outlet of the uppermost BES module to the second water distributor; after entering the MBBR unit through the second water distributor, it flows through each MBBR module in the MBBR unit in sequence, and the treated water is discharged from the uppermost MBBR module.

[0011] The hybrid dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor and its working method proposed by the present invention have many remarkable beneficial effects:

[0012] ​Technical synergy advantage: Innovatively combine the bioelectrochemical technology with the moving bed biofilm reactor process. In the bioelectrochemical technology, electroactive microorganisms and electrodes play a synergistic role, enabling the efficient degradation of wastewater that is difficult to treat by traditional processes. The moving bed biofilm reactor loads a rich variety of functional microorganisms through carriers, and the biofilm carriers move continuously, constantly colliding with water flow and bubbles, greatly increasing the contact area between microorganisms and refractory wastewater, and significantly enhancing the ability to remove pollutants. The advantages of the two complement each other, opening up a new path for the deep degradation and mineralization of refractory mixed wastewater.

[0013] Efficient hierarchical treatment: The wastewater treatment process can gradually achieve the goals of removing and mineralizing refractory wastewater. First, the wastewater flows into the BES module, where, under the combined action of functional microorganisms and electrochemistry, the refractory pollutants are deeply detoxified and transformed into non-toxic or low-toxic intermediate metabolites. Then, the detoxified wastewater enters the MBBR module, where the intermediate metabolites are completely degraded and utilized, converted into CO2 and H2O, successfully achieving the deep mineralization of pollutants.

[0014] Module stacking for enhanced efficiency: Stack and assemble the BES module and the MBBR module respectively, enhancing the synergy between the modules. This stacking design can perform gradient degradation on refractory wastewater, significantly improving the degradation efficiency of pollutants. At the same time, the multi-stage module stacking weakens the impact of water quality changes on the system. The microorganisms in each module enhance their adaptability to water quality performance, effectively weakening the reduction of the overall performance, and having the feasibility and advantages of improving wastewater treatment performance and realizing reactor scale-up. And the stacking number of the BES module and the MBBR module can be flexibly assembled according to actual needs.

[0015] Optimized electrode arrangement: In the BES module, a surrounding electrode arrangement is adopted. This design shortens the distance between the anode and the cathode, reduces the internal resistance of the reactor, enhances the electron transfer efficiency between the anode and the cathode and the proton diffusion efficiency in the anode and cathode chambers, thereby improving the removal efficiency of refractory wastewater.

[0016] Excellent overall performance: The present invention has the characteristics of simple configuration, convenient assembly, strong practicability, and easy operation. Compared with a single dye wastewater degradation device, it can achieve the deep degradation of various mixed dye wastewaters and has higher applicability and promotion value in actual industrial applications. Brief description of the drawings

[0017] Figure 1 It is a schematic structural diagram of a hybrid dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor;

[0018] Figure 2 It is a comparison chart of the treatment efficiency of each stage module on mixed dyes in the BES-MBBR coupling process. Detailed implementation mode

[0019] Detailed implementation mode 1: This implementation mode will be described in conjunction with the accompanying drawings. A hybrid dye wastewater treatment device based on the coupling of bioelectrochemistry and a moving bed biofilm reactor in this implementation mode consists of a first water distributor 1, a second water distributor 3, a BES unit 2, and an MBBR unit 4; the first water distributor 1 is arranged at the bottom of the BES unit 2 and is communicated with the BES unit 2; the second water distributor 3 is arranged at the bottom of the MBBR unit 4 and is communicated with the MBBR unit 4; the wastewater inlet 5 is arranged at the bottom of the first water distributor 1, and the treated water outlet 6 is arranged at the upper part of the MBBR unit 4.

[0020] The BES unit 2 is formed by connecting several BES modules in series in the vertical direction. The bottom of the BES module is provided with an inlet, and the upper part is provided with an outlet. The inlets and outlets of adjacent modules are connected through conduits. Adjacent modules are connected by flanges and sealed with silicone rubber rings.

[0021] The MBBR unit 4 is formed by connecting several MBBR modules in series in the vertical direction. The bottom of the MBBR module is provided with an inlet, and the upper part is provided with an outlet. The inlets and outlets of adjacent modules are connected through conduits. Adjacent modules are connected by flanges and sealed with silicone rubber rings.

[0022] Detailed implementation mode 2: The difference between this implementation mode and detailed implementation mode 1 is that: the number of BES modules in the BES unit 2 is 3; the number of MBBR modules in the MBBR unit 4 is 3. Others are the same as detailed implementation mode 1.

[0023] Detailed implementation mode 3: The difference between this implementation mode and detailed implementation mode 1 is that: the BES module adopts a sleeve structure with a circumferential electrode arrangement, which is composed of two parts, an inner cylinder and an outer cylinder; small holes are evenly distributed on the surface of the inner cylinder, and a cation exchange membrane is pasted on the surface of the inner cylinder; this cation exchange membrane divides the main body of the BES module into two independent chambers, namely the inner anodic chamber and the outer cathodic chamber; an anode is placed in the anodic chamber, and a cathode is placed in the cathodic chamber; the materials used for the anode and the cathode are both carbon brushes; the anode and the cathode are connected through wires, a power supply, and an external resistor to form a closed loop; the electrode ratio of the cathode to the anode is 3:1. Others are the same as detailed implementation mode 1.

[0024] Detailed implementation mode 4: The difference between this implementation mode and detailed implementation mode 3 is that: the material of the carbon brush is carbon fiber, carbon particles, graphite particles, carbon felt, carbon cloth, stainless steel mesh, nickel foam, or other modified electrode materials. Others are the same as detailed implementation mode 3.

[0025] Specific embodiment 5: This embodiment differs from specific embodiment 1 in that the cylinder of the MBBR module is filled with porous plastic bio-carriers that occupy 40% of the cylinder volume for fixing the biofilm. Other aspects are the same as those of specific embodiment 1.

[0026] Specific embodiment 6: This embodiment differs from specific embodiment 5 in that the porous plastic biological carrier is polyethylene, polyvinyl chloride, polypropylene or other modified filling materials. Other aspects are the same as those of specific embodiment 5.

[0027] Specific implementation method seven: A working method of a mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and a moving bed biofilm reactor, which is carried out according to the following steps:

[0028] 1. Before assembling the device, the BES module was inoculated with activated sludge for acclimatization, and the anode influent was a glucose solution of 1000 mg L -1 , cathode water mixed dye 200mg L -1 + Glucose 1000mg L -1 The anode and cathode biofilms were successfully grown, and the BES module was assembled after stable operation for at least 10 days. The MBBR module was inoculated with aerobic activated sludge, and the influent glucose solution was 1000 mg L -1 , aeration and acclimatization culture to achieve successful biofilm formation of biofillers for MBBR module assembly; then assemble the BES-MBBR coupling device;

[0029] 2. After assembly, the mixed dye wastewater first enters the BES unit 2 through the first water distributor 1, flows through the various BES modules in the BES unit 2 in turn, and is sent to the second water distributor 3 from the water outlet of the top BES module; after entering the MBBR unit 4 through the second water distributor 3, it flows through the various MBBR modules in the MBBR unit 4 in turn, and the treated water is discharged from the top MBBR module.

[0030] Before the device assembly in this embodiment, the BES module is inoculated with activated sludge for acclimation. Glucose solution is fed into the anode, and a mixed dye and glucose solution are fed into the cathode. After at least 10 days of stable operation, successful biofilm formation on the anode and cathode is achieved. This process enriches a large number of microorganisms with specific functions on the electrode surface. These microorganisms can participate in the degradation of the mixed dye through their own metabolic activities during subsequent treatment, providing a biological basis for the efficient treatment of mixed dye wastewater. The BES unit uses glucose as a co-substrate and, together with the mixed dye wastewater, is fed into the cathode. The presence of glucose can provide additional carbon sources and energy for microorganisms, promoting their growth and metabolic activities, enabling them to better play their role in degrading the mixed dye. During the process of microorganisms using glucose for metabolism, some substances or enzymes with redox activity are produced. These substances or enzymes can participate in the degradation reaction of the mixed dye, helping to break the complex structure in the dye molecule, especially acting on difficult-to-break chemical bonds such as azo bonds, so that the mixed dye is more easily degraded. A voltage of 0.7V is applied externally to the BES unit, and the cathode and anode are connected into a closed loop through a wire and an external resistor. Under the action of the electric field, a series of redox reactions occur on the electrode surface, generating strongly oxidizing substances such as hydroxyl radicals. These strongly oxidizing substances can react chemically with the mixed dye molecules, attacking the aromatic structure and azo bonds in the dye molecules, breaking them, converting the complex mixed dye molecules into relatively simple intermediate products, reducing the toxicity and complexity of the mixed dye, improving the biodegradability of the wastewater, and creating favorable conditions for the further treatment of the subsequent MBBR module.

[0031] In this embodiment, the MBBR module is inoculated with aerobic activated sludge, and successful biofilm formation on the biological filler is achieved through aeration acclimation and cultivation. A large number of aerobic microorganisms are attached to the surface of the biofilm after biofilm formation. These microorganisms have rich enzyme systems and metabolic pathways and can further degrade and utilize the intermediate products of the mixed dye wastewater treated by the BES module. The biological film carriers in the MBBR module are in a continuous motion state, constantly colliding with the water flow and bubbles, increasing the contact area between microorganisms and wastewater, and improving the mass transfer efficiency. This enables microorganisms to more fully contact and uptake pollutants in the wastewater, including the residual intermediate products after BES module treatment, thus enhancing the treatment effect on the mixed dye wastewater and facilitating the complete degradation and mineralization of pollutants. The filling rate of the filler in the MBBR unit is 40%, and the dissolved oxygen concentration is about 3mg L -1 , the HRT is 12h. These conditions provide a suitable environment for the growth and metabolism of aerobic microorganisms. Under such conditions, aerobic microorganisms can maintain a high activity, fully exert their degradation ability on the intermediate products of the mixed dye wastewater, completely degrade them, achieve deep mineralization of pollutants, and thus effectively remove pollutants in the mixed dye wastewater and reduce its harm to the ecological environment.

[0032] In this embodiment, the mixed dye wastewater first enters the BES unit and then enters the MBBR unit after being treated by the BES module. This design forms a process of gradient degradation. The BES module is mainly responsible for the preliminary transformation and detoxification of the refractory mixed dyes, providing intermediate products that are easier to treat for the MBBR module; the MBBR module further degrades and mineralizes these intermediate products. The two modules cooperate with each other and work synergistically, enabling the mixed dye wastewater to be treated specifically at different stages, thereby improving the overall treatment effect and being able to more effectively solve the problem that the mixed dye wastewater is difficult to be completely degraded. The BES-MBBR coupling device adopts a design of multi-stage module stacking. The microorganisms in each module can enhance their adaptability to water quality performance by gradually adapting to the changes in water quality, thereby weakening the impact of water quality changes on the overall performance of the system. Even if there are certain fluctuations in the water quality of the mixed dye wastewater, the system can still maintain a relatively stable treatment effect, ensuring the effective treatment of the mixed dye wastewater and reducing its harm to the ecological environment.

[0033] Specific Embodiment VIII: The difference between this embodiment and Specific Embodiment VII is that the mixed dye wastewater is Congo red, acid orange, reactive black, disperse blue or other types of azo dyes. Others are the same as Specific Embodiment VII.

[0034] Specific Embodiment IX: The difference between this embodiment and Specific Embodiment VII is that the applied voltage of the BES unit 2 is 0.7V and the resistance is 20Ω; the dissolved oxygen concentration of the MBBR unit 4 is 3mg L -1 . Others are the same as Specific Embodiment VII.

[0035] Specific Embodiment X: The difference between this embodiment and Specific Embodiment VII is that the HRT of both the BES unit 2 and the MBBR unit 4 is 12h. Others are the same as Specific Embodiment VII.

[0036] The following examples are used to verify the technical effects of the present invention:

[0037] Example: A working method of a mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor is carried out according to the following steps:

[0038] I. Before the device is assembled, the BES module is inoculated with activated sludge for domestication. The glucose solution of 1000mg L is fed into the anode, -1 , and the mixed dye of 200mg L is fed into the cathode, -1 + glucose of 1000mg L, -1 to achieve successful film formation on the anode and cathode. After stable operation for at least 10 days, the BES module is assembled; the MBBR module is inoculated with aerobic activated sludge, and the glucose solution of 1000mg L is fed into the water,-1 Through aeration acclimation cultivation, successful biofilm formation on the biological packing was achieved for the MBBR module assembly; then the assembly of the BES-MBBR coupling device was carried out; the electrode ratio of the cathode to the anode was 3:1, and the two were connected into a closed circuit through wires and an external resistor. Among them, the power supply voltage was 0.7V and the external resistor was 20Ω. The anode substrate was glucose, and the cathode substrates were mixed dyes and glucose;

[0039] Second, after the assembly was completed, the mixed dye wastewater first entered the BES unit 2 through the first water distributor 1, flowed through each BES module in the BES unit 2 in sequence, and was sent to the second water distributor 3 from the water outlet of the uppermost BES module; after entering the MBBR unit 4 through the second water distributor 3, it flowed through each MBBR module in the MBBR unit 4 in sequence, and the treated water was discharged from the uppermost MBBR module; the mixed dye wastewater was composed of Congo red, acid orange, reactive black, and disperse blue; a voltage of 0.7V was applied outside the BES unit 2, using glucose as a co-substrate, and 200mg L -1 The simulated mixed dye wastewater was used as the cathode influent. The effluent from the BES process subsequently entered the three-stage MBBR stacked process. The packing filling rate of the MBBR unit 4 was 40%, and the dissolved oxygen concentration was about 3mg L -1 . The HRT of both the BES unit 2 and the MBBR unit 4 was 12h.

[0040] The experimental results are as follows:

[0041] As Figure 2 shown in A, the BES-MBBR coupling process can improve the decolorization, COD removal, total nitrogen and ammonia nitrogen removal of mixed dyes, and the corresponding removal rates are 95.6%, 93.3%, 30.7% and 73.3% respectively.

[0042] As Figure 2 shown in B, in terms of decolorization performance, the decolorization rates of BES-1, BES-2, BES-3, MBBR-1, MBBR-2, and MBBR-3 are 46.3%, 33.1%, 12.8%, 1.7%, 0.9%, and 0.8% respectively, and the total decolorization rate is 95.6%. Among them, the contribution of the BES stage to the decolorization rate is 92.2%, and the contribution of the MBBR stage is 3.4%. This indicates that the BES stage plays a major role in decolorization, while the role of MBBR is not significant.

[0043] In terms of COD removal performance, the COD removal rates of BES-1, BES-2, BES-3, MBBR-1, MBBR-2, and MBBR-3 were 17.1%, 9.6%, 5.2%, 35.2%, 18.3%, and 7.9% respectively. The total COD removal rate was 93.3%. Among them, the contribution of the BES stage to the COD removal rate was 31.9%, and the contribution of the MBBR stage was 61.4%. This indicates that the removal of COD in the BES-MBBR combined process is the result of the combined action of the BES stage and the MBBR stage, with the MBBR stage playing a major role.

[0044] In terms of the removal performance of total nitrogen, the total nitrogen removal rates of BES-1, BES-2, BES-3, MBBR-1, MBBR-2, and MBBR-3 were 1.4%, 1.1%, 1.2%, 11.7%, 8.1%, and 7.2% respectively. The total total nitrogen removal rate was 30.7%. Among them, the contribution of the BES stage to the total nitrogen removal was 3.7%, and the contribution of the MBBR stage was 27.0%.

[0045] In terms of the removal performance of ammonia nitrogen, the ammonia nitrogen removal rates of BES-1, BES-2, BES-3, MBBR-1, MBBR-2, and MBBR-3 were 1.0%, 1.2%, 1.4%, 36.6%, 22.3%, and 10.8% respectively. The total ammonia nitrogen removal rate was 73.3%. Among them, the contribution of the BES stage to the ammonia nitrogen removal was 3.6%, and the contribution of the MBBR stage was 69.7%.

[0046] In summary, in the device for treating mixed dye wastewater by the BES-MBBR coupling process, first, in the BES stage, the functional microorganisms in the anode chamber can utilize the electrons and carbon sources generated during the glucose fermentation process, enabling a large amount of electrons to be enriched in the anode and continuously transferred to the cathode for the electrons required for dye reduction and detoxification. In addition, the functional microorganisms in the cathode chamber can not only utilize the electrons transferred from the anode for metabolic activities but also rely on the electroactive bacteria in the cathode to enhance electron transfer. This accelerates the cleavage of the azo bond in the mixed dye and generates aromatic ammonium organic compounds to achieve decolorization. Second, in the MBBR stage, under the action of aerobic microbial metabolism, the intermediate metabolites of azo dyes are cleaved and finally further transformed into CO2 and H2O, ultimately achieving the decolorization and mineralization of the dyes. The present invention can achieve the purpose of efficiently and rapidly treating azo dye wastewater and further deeply mineralizing its metabolites, providing a theoretical basis and reference for the integrated treatment of printing and dyeing wastewater by multiple processes. In addition, the present invention is important for meeting the requirements of adjustable and controllable new process development in the future and for the popularization and application of the coupling of bioelectrochemical technology and aerobic biological treatment technology.

Claims

1. A mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor, characterized in that The mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor comprises a first water distributor (1), a second water distributor (3), a BES unit (2) and an MBBR unit (4); the first water distributor (1) is arranged at the bottom of the BES unit (2) and is connected to the BES unit (2); the second water distributor (3) is arranged at the bottom of the MBBR unit (4) and is connected to the MBBR unit (4); the wastewater inlet (5) is arranged at the bottom of the first water distributor (1), and the treated water outlet (6) is arranged at the upper part of the MBBR unit (4); The BES unit (2) is composed of a plurality of BES modules connected in series in a vertical direction. A water inlet is arranged at the bottom of the BES module and a water outlet is arranged at the top. The water inlets and water outlets of adjacent modules are connected through a conduit. Adjacent modules are connected through flanges and sealed with a silicone ring. The MBBR unit (4) is composed of several MBBR modules connected in series in the vertical direction. A water inlet is arranged at the bottom of the MBBR module and a water outlet is arranged at the top. The water inlets and outlets of adjacent modules are connected through a conduit. Adjacent modules are connected through flanges and sealed with silicone rings.

2. The mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor according to claim 1 is characterized in that The number of BES modules in the BES unit (2) is 3; the number of MBBR modules in the MBBR unit (4) is 3.

3. The mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor according to claim 1 is characterized in that The BES module adopts a sleeve structure with a surrounding electrode arrangement, which consists of an inner tube and an outer tube; small holes are evenly distributed on the surface of the inner tube, and a cation exchange membrane is attached to the surface of the inner tube; the cation exchange membrane separates the main body of the BES module into two independent chambers, namely an internal anode chamber and an external cathode chamber; an anode is placed in the anode chamber, and a cathode is placed in the cathode chamber; the materials used for the anode and the cathode are both carbon brushes; the anode and the cathode are connected by a wire, a power supply and an external resistor to form a closed loop; the electrode ratio of the cathode to the anode is 3:

1.

4. The mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor according to claim 3 is characterized in that The material of the carbon brush is carbon fiber, carbon particles, graphite particles, carbon felt, carbon cloth, stainless steel mesh, foamed nickel or other modified electrode materials.

5. The mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor according to claim 1 is characterized in that The MBBR module's cylinder is filled with porous plastic bio-carriers that occupy 40% of the cylinder's internal volume and are used to fix the biofilm.

6. The mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor according to claim 5 is characterized in that The porous plastic biological carrier is polyethylene, polyvinyl chloride, polypropylene or other modified filling materials.

7. The working method of the mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor as claimed in claim 1, characterized in that It is carried out in the following steps:

1. Before module assembly, the BES module was inoculated with activated sludge for acclimatization, and the anode influent was 1000 mg L glucose solution. -1 , cathode water mixed dye 200mg L -1 + Glucose 1000mg L -1 , the anode and cathode are successfully coated, and the device is assembled after stable operation for at least 10 days; 2. After the assembly is completed, the mixed dye wastewater first enters the BES unit (2) through the first water distributor (1), flows through the various BES modules in the BES unit (2) in turn, and is sent to the second water distributor (3) from the water outlet of the top BES module; after entering the MBBR unit (4) through the second water distributor (3), it flows through the various MBBR modules in the MBBR unit (4) in turn, and the treated water is discharged from the top MBBR module.

8. The working method of the mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor according to claim 7 is characterized in that The mixed dye wastewater is Congo red, acid orange, reactive black, disperse blue or other types of azo dyes.

9. The working method of the mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor according to claim 7 is characterized in that The applied voltage of the BES unit (2) is 0.7 V and the resistance is 20 Ω; the dissolved oxygen concentration of the MBBR unit (4) is 3 mg L -1 .

10. The working method of the mixed dye wastewater treatment device based on the coupling of bioelectrochemistry and moving bed biofilm reactor according to claim 7, characterized in that The HRT of the BES unit (2) and the MBBR unit (4) are both 12 h.

Images