Organic wastewater treatment system and method based on electrochemical microorganism and biochemical coupling

Abstract

The invention discloses an organic wastewater treatment system and method based on electrochemical microorganism and biochemical coupling, comprising an electrobiochemical three-chamber, an MBR chamber, a Fenton-like pool, an intermediate pool and a battery, wherein the electrobiochemical three-chamber comprises a left cathode reaction chamber, an anode reaction chamber and a right cathode reaction chamber connected in sequence from left to right; the MBR chamber is respectively connected with the anode reaction chamber, the Fenton-like pool and the intermediate pool, the intermediate pool is respectively connected with the left cathode reaction chamber, the Fenton-like pool and the MBR chamber, and the Fenton-like pool is respectively connected with the left cathode reaction chamber, the right cathode reaction chamber, the intermediate pool and the MBR chamber. The invention couples a dual cathode electrobiochemical + Fenton-like process, so that the organic matter self-degradation system becomes the source of the Fenton reagent, the device has very few external reagents, the generated sludge can be recycled, and the treatment cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of advanced oxidation of organic wastewater, and relates to an organic wastewater treatment system using electrochemical microorganisms and biochemical coupling technology. Background Art

[0002] The Fenton process has been widely used for the advanced oxidation treatment of organic wastewater. However, its application has been limited by its specific reagent requirements, high sludge production, and the toxicity of residual hydrogen peroxide. In recent years, research on the Fenton reaction has focused on reducing the amount of Fenton reagent, expanding the pH range of the Fenton reaction, improving the utilization of hydrogen peroxide, and reducing Fenton sludge.

[0003] At present, the biochemical method is the most economical and widely used method for treating organic wastewater. Bioelectrochemistry is one of the enhanced technologies of the biochemical method. Its microbial intermediaries at the cathode and anode participate in electron transfer. The large amount of electrons flowing in the system can open long-chain macromolecular refractory organic matter, overcome the shortcomings of conventional biochemistry, and improve the biodegradability of wastewater and the removal rate of organic matter. The cost of electrode materials and the applicability of wastewater are limitations to the promotion and application of bioelectrochemistry; advanced oxidation method is an effective method for treating refractory organic wastewater, but the treatment cost is generally high. Fenton is a representative of advanced oxidation method. Based on the homogeneous Fenton system, a series of Fenton-like reaction systems have been developed. To a certain extent, they can solve the limitations of Fenton itself, but the process is simple and still requires the addition of Fenton reagents. There is no Fenton sludge recovery unit, and the effluent stability is poor.

[0004] Fenton sludge is mainly composed of organic components such as carbon, oxygen, hydrogen, nitrogen, and sulfur, as well as heavy metal components such as Fe, Mg, Cu, As, Ni, Cr, and Zn. How to utilize Fenton reagents and Fenton sludge as resources has become a difficult point. Summary of the Invention

[0005] Purpose of the invention: In order to solve the problems of low reagent utilization and high sludge production in the Fenton process for treating organic wastewater, the present invention provides an organic wastewater treatment system based on electrochemical microbial and biochemical coupling.

[0006] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] An organic wastewater treatment system based on electrochemical microbial and biochemical coupling includes an electro-biochemical three-chamber, an MBR chamber, a Fenton-like tank, an intermediate tank and a battery, wherein:

[0008] The electrobiochemical three-chamber includes a left cathode reaction chamber, an anode reaction chamber and a right cathode reaction chamber connected in sequence from left to right. The positive pole of the battery is connected to the anode reaction chamber, and the negative pole of the battery is connected to the left cathode reaction chamber and the right cathode reaction chamber respectively; a wastewater inlet pipeline is provided on the anode reaction chamber.

[0009] The anode reaction chamber is used to perform oxidation reaction on the organic wastewater and the muddy water from the MBR chamber to initially remove and degrade it. Under the action of the proton membrane, the water molecules and some cations of the organic wastewater enter the left and right cathode reaction chambers on both sides. After being treated in the anode reaction chamber, the organic wastewater enters the MBR chamber.

[0010] The left cathode reaction chamber is used to treat water molecules and some cations from the anode reaction chamber and the muddy water pumped into the middle tank. Under the action of iron-reducing bacteria and slightly acidic conditions, the iron-reducing bacteria decompose organic matter in an anaerobic environment to obtain electrons, and convert the trivalent iron ions in the iron sludge into divalent iron ions.

[0011] The right cathode reaction chamber is used to produce hydrogen peroxide by a two-electron oxygen reduction reaction of oxygen under the catalysis of nitrogen-carbon-based materials and slightly acidic conditions;

[0012] The MBR chamber is used to further biochemically degrade the wastewater from the anode reaction chamber through membrane biological reaction under membrane components and aeration conditions;

[0013] The intermediate tank is used to oxidize pollutants with hydrogen peroxide in the iron sludge from the Fenton tank reaction and the effluent from the MBR chamber;

[0014] A Fenton-like tank is used for Fenton reaction of hydrogen peroxide from the right cathode reaction chamber, wastewater from the MBR chamber, and sludge from the left cathode reaction chamber.

[0015] Preferably, the outlet pipe of the anode reaction chamber is connected to the water inlet pipe of the MBR chamber through the MBR water inlet pipeline, and the return pipe of the MBR chamber is connected to the mud feeding pipe of the anode reaction chamber through the MBR return pipeline.

[0016] The treated wastewater pipe of the MBR chamber is connected to the water inlet pipe of the intermediate pool through the intermediate pool water inlet pipeline, and the treated wastewater pipe of the MBR chamber is connected to the water inlet pipe of the Fenton-like pool through the MBR Fenton inlet pipeline.

[0017] The hydrogen peroxide outlet pipe of the right cathode reaction chamber is connected to the hydrogen peroxide inlet pipe of the Fenton-like tank through the hydrogen peroxide delivery pipeline, and the sludge outlet pipe of the left cathode reaction chamber is connected to the sludge recycling pipe of the Fenton-like tank through the sludge regeneration and recycling pipeline.

[0018] The mud outlet pipe of the Fenton-like pool is connected to the mud inlet pipe of the intermediate pool through the intermediate pool mud inlet pipeline.

[0019] The mud outlet pipe of the intermediate tank is connected to the mud inlet pipe of the left cathode reaction chamber through the intermediate tank mud outlet pipeline.

[0020] Preferably, the left cathode reaction chamber is provided with an iron-reducing bacteria activated sludge layer and a left cathode, the lower portion of the left cathode being inserted into the iron-reducing bacteria activated sludge layer, the left cathode being constructed of a carbon fiber-coated graphene structure, and a composite filler layer being disposed on the surface of the carbon fiber-coated graphene structure. The negative electrode of the battery is connected to the left cathode.

[0021] Preferably, an anaerobic activated sludge layer and an anode are provided in the anode reaction chamber, the anaerobic activated sludge layer is inserted into the lower portion of the anode, the anode is a carbon fiber-coated graphene structure, and a composite filler layer is provided on the surface of the carbon fiber-coated graphene structure. The positive electrode of the battery is connected to the anode.

[0022] Preferably, the right cathode reaction chamber is provided with a right cathode and aerator 1, the right cathode being a carbon-based material-supported gas diffusion electrode with a nitrogen content of 6%, and the right cathode being located above aerator 1. The negative electrode of the battery is connected to the right cathode.

[0023] Preferably, two or more membrane modules are provided in the MBR chamber, and a second aerator is provided below the membrane modules.

[0024] Preferably, the left cathode reaction chamber, the anode reaction chamber and the right cathode reaction chamber are separated by a proton membrane.

[0025] Preferably, the Fenton-like pool is provided with a water outlet pipe. An α-FeooH particle layer is provided in the Fenton-like pool.

[0026] Another object of the present invention is to provide a method for resource-based treatment of organic wastewater based on electrochemical microbial and biochemical coupling, characterized in that the method comprises the following steps:

[0027] Step 1: pumping organic wastewater into the anode reaction chamber of the electro-biochemical three-chamber through the water inlet pipeline;

[0028] Step 2: In the anode reaction chamber, organic wastewater and muddy water from the MBR chamber are received. At the same time, organic pollutants in the organic wastewater easily lose electrons at the anode, undergoing an oxidation reaction. Combined with the biological synergistic effect of the anode external composite filler layer, they are initially removed and degraded under the effects of oxidation, biochemistry, and adsorption. Under the action of the proton membrane, water molecules and some cations in the organic wastewater enter the left cathode reaction chamber and the right cathode reaction chamber on both sides, causing hydrogen ions in the left cathode reaction chamber and the right cathode reaction chamber to accumulate and make the solution slightly acidic. After being treated in the anode reaction chamber, the organic wastewater enters the MBR chamber through the MBR water inlet pipe.

[0029] The left cathode reaction chamber receives water molecules and some cations from the anode reaction chamber, as well as muddy water pumped into the intermediate tank. Under the action of iron-reducing bacteria and slightly acidic conditions, the iron-reducing bacteria decompose organic matter in an anaerobic environment to obtain electrons, converting the trivalent iron ions in the iron sludge into divalent iron ions. The sludge is then connected to the sludge return pipe of the Fenton-like tank through the sludge regeneration and reuse pipeline, providing a reducing agent for the Fenton tank.

[0030] In the right cathode reaction chamber, dissolved oxygen and escaped oxygen are provided by microporous aerator 1. The right cathode is a gas diffusion electrode. Under the catalysis of nitrogen-carbon-based materials and slightly acidic conditions, oxygen undergoes a two-electron oxygen reduction reaction to produce hydrogen peroxide. A certain concentration of hydrogen peroxide produced in the right cathode reaction chamber enters the Fenton-like cell through the hydrogen peroxide delivery pipeline, providing an oxidant for the Fenton reaction.

[0031] Step 3: In the MBR chamber, wastewater from the anode reaction chamber is received. There are multiple membrane modules in the MBR chamber, and the wastewater undergoes membrane biological reaction under the membrane modules and aeration conditions for further biochemical degradation.

[0032] The return pipe of the MBR chamber is connected to the mud feeding pipe of the anode reaction chamber through the MBR return pipeline;

[0033] The effluent from the MBR chamber flows through the MBR Fenton inlet pipe to the Fenton-like tank for deep organic matter oxidation and decomposition. The wastewater in the Fenton-like tank undergoes Fenton reaction with a pH range of 5-6. The reaction effluent is discharged through the effluent pipe, and the iron sludge from the reaction flows into the intermediate tank through the intermediate tank inlet pipe.

[0034] The other branch of the MBR chamber effluent flows into the middle tank through the middle tank inlet pipe, so that the sludge in the middle tank does not dry out and block, and at the same time serves as a carbon source for the iron-reducing bacteria in the left cathode reaction chamber;

[0035] Step 4: The intermediate tank receives the iron sludge from the Fenton-like reaction and the effluent from the MBR chamber. The effluent from the iron sludge and the MBR chamber is stored in the intermediate tank. The remaining hydrogen peroxide in the iron sludge oxidizes the pollutants, reduces the dissolved oxygen in the iron sludge liquid, and then is circulated through the intermediate tank effluent pipeline pump into the left cathode reaction chamber.

[0036] Step 5, in the Fenton-like tank, hydrogen peroxide from the right cathode reaction chamber, wastewater from the MBR chamber, and sludge from the left cathode reaction chamber are received; at the initial start-up of the Fenton-like tank reaction, ferrous sulfate solution is added; after normal startup, the Fenton oxidant comes from the hydrogen peroxide in the cathode reaction chamber, and the Fenton reductant comes from the divalent iron ions in the sludge in the left cathode reaction chamber. The wastewater undergoes Fenton reaction in the Fenton-like tank under the action of hydrogen peroxide and divalent iron ions; the reacted iron sludge is pumped into the middle tank, and the reacted wastewater is discharged from the outlet pipe.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] This device couples a dual cathode electro-biochemical + Fenton-like process, making the organic matter's own degradation system the source of the Fenton reagent. The device requires very few external reagents, the generated sludge can be recycled, and the treatment cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the structure of an embodiment of the present invention.

[0040] In the figure, 1 is the electro-biochemical three-chamber, 11 is the battery, 12 is the anode, 13 is the combined filler, 14 is the left cathode, 15 is the right cathode, 16 is the hydrogen peroxide delivery pipeline, 171 is the aerator one, 172 is the aerator two, 18 is the proton membrane, 19 is the water inlet pipeline, 2 is the MBR chamber, 21 is the MBR water inlet pipeline, 22 is the MBR return pipeline, 23 is the intermediate pool water inlet pipeline, 24 is the MBR Fenton pipeline, 3 is the Fenton-like pool, 31 is the sludge regeneration and reuse pipeline, 32 is the α-FeooH particle layer, 33 is the outlet pipeline, 4 is the intermediate pool, 41 is the intermediate pool mud inlet pipeline, 42 is the intermediate pool mud outlet pipeline, 101 is the left cathode reaction chamber, 102 is the anode reaction chamber, and 103 is the right cathode reaction chamber. DETAILED DESCRIPTION

[0041] The present invention is further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, modifications of various equivalent forms of the present invention made by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0042] An organic wastewater treatment system based on electrochemical microorganisms and biochemical coupling, through the coupling process of electrochemical redox + water treatment microorganisms + biofilm + Fenton-like organic matter removal, realizes the recycling of reagents and sludge in Fenton-like technology, such as Figure 1 As shown, it includes an electro-biochemical three-chamber 1, an MBR chamber 2, a Fenton-like tank 3, an intermediate tank 4 and a battery 11, wherein:

[0043] The electro-biochemical three-chamber 1 comprises a left cathode reaction chamber 101, an anode reaction chamber 102 and a right cathode reaction chamber 103 which are sequentially connected from left to right. A wastewater inlet pipe 19 is provided on the anode reaction chamber 102.

[0044] The anode reaction chamber 102 is used to perform an oxidation reaction to initially remove and degrade organic wastewater and muddy water from the MBR chamber 2. Under the action of the proton membrane 18, water molecules and some cations in the organic wastewater enter the left cathode reaction chamber 101 and the right cathode reaction chamber 103 on both sides. After being treated in the anode reaction chamber 102, the organic wastewater enters the MBR chamber 2.

[0045] The left cathode reaction chamber 101 is used to treat water molecules and some cations from the anode reaction chamber 102 and the muddy water pumped into the intermediate tank 4. Under the action of iron-reducing bacteria and slightly acidic conditions, the iron-reducing bacteria decompose organic matter in an anaerobic environment to obtain electrons, and convert the trivalent iron ions in the iron sludge into divalent iron ions.

[0046] The right cathode reaction chamber 103 is used to generate hydrogen peroxide by a two-electron oxygen reduction reaction of oxygen under the catalysis of nitrogen-carbon-based materials and slightly acidic conditions;

[0047] MBR chamber 2, for further biochemical degradation of wastewater from the anode reaction chamber 102 by membrane biological reaction under membrane modules and aeration conditions;

[0048] The intermediate tank 4 is used to oxidize pollutants with hydrogen peroxide in the iron sludge from the Fenton-like tank 3 and the effluent from the MBR chamber 2;

[0049] The Fenton-like tank 3 is used for the Fenton reaction of hydrogen peroxide from the right cathode reaction chamber 103 , wastewater from the MBR chamber 2 , and sludge from the left cathode reaction chamber 101 .

[0050] Organic wastewater enters the anode reaction chamber 102 through the wastewater inlet pipe 19. Active bacteria with strong oxidizing ability are cultivated and domesticated in the anode reaction chamber 102 to degrade organic matter. Purified iron-reducing bacteria are cultivated in the left cathode reaction chamber 101 to regenerate divalent iron reagent. The right cathode reaction chamber 103 uses natural air diffusion to select electrodes to synthesize hydrogen peroxide reagent. Proton membranes 18 are set between different chambers to carry out directional selective movement and accumulation of different substances in the water. The iron-containing sludge of the Fenton-like tank 3 is returned to the left cathode reaction chamber 101 of the electro-biochemical three-chamber, and divalent iron ions are generated under the action of the external electric field and iron-reducing bacteria and reused in the Fenton-like tank 3.

[0051] In another embodiment, the left cathode reaction chamber 101, the anode reaction chamber 102, and the right cathode reaction chamber 103 are separated by a proton membrane 18. Hydrogen ions from the anode migrate directionally through the proton membrane to the cathode, making the solution in the right cathode reaction chamber 103 weakly acidic. The proton membrane also prevents generated hydrogen peroxide from dispersing into the anode of the anodic oxidation cell and microorganisms. Oxygen in the gas diffusion electrode is provided by a microporous aerator located at the bottom.

[0052] In another example, an iron-reducing bacteria activated sludge layer and a left cathode 14 are provided in the left cathode reaction chamber 101, the lower part of the left cathode 14 is inserted into the iron-reducing bacteria activated sludge layer, and activated sludge containing a large amount of iron-reducing bacteria is put into the iron-reducing bacteria activated sludge layer. The left cathode 14 adopts a carbon fiber-wrapped graphene structure, and a composite filler layer 13 is provided on the surface of the carbon fiber-wrapped graphene structure. The composite filler layer 13 is formed by externally hanging a composite filler on the carbon fiber-wrapped graphene structure. By adopting the carbon fiber-wrapped graphene structure, the outermost layer of the composite filler serves as an activated sludge growth carrier.

[0053] The left cathode reaction chamber 101 is inoculated with iron-reducing bacteria. Under anaerobic conditions, the bacteria decompose organic matter to obtain electrons and reduce iron ions. The electrons are directly obtained at the battery cathode and then transferred to the iron ions through intermediaries such as cytochrome c and nanowires, accelerating the reaction rate. Furthermore, the reduction potential of Fe₃⁺ / Fe₂⁺ is 0.44V, and the graphene wrapped around the left cathode has a reduction potential greater than 0.44V, effectively promoting the reduction of iron ions by the iron-reducing bacteria. The pH of the left cathode reaction chamber 101 is controlled between 5 and 6.5 to ensure the solubility of iron ions under slightly acidic conditions.

[0054] In another example, an anaerobic activated sludge layer and an anode 12 are provided within the anode reaction chamber 102. The anaerobic activated sludge layer is inserted into the lower portion of the anode 12, and anaerobic activated sludge is introduced into the anaerobic activated sludge layer. The anode 12 utilizes a carbon fiber-coated graphene structure, and a composite filler layer 13 is provided on the surface of the carbon fiber-coated graphene structure. Organic matter within the anode reaction chamber undergoes an oxidative reaction and initial degradation under the action of the anode and microorganisms.

[0055] In another example, the right cathode reaction chamber 103 is provided with a right cathode 15 and an aerator 171 . The right cathode 15 is a carbon-based material-loaded gas diffusion electrode with a nitrogen content of 6%. The right cathode 15 is located above the aerator 171 .

[0056] The right cathode uses a gas diffusion electrode (GDE), a porous, three-dimensional electrode consisting of a diffusion layer, a catalytic layer, and a current collecting layer. Oxygen passes through the diffusion layer to the catalytic layer, where it reacts with the solution in the interstices of the catalytic layer, significantly increasing the contact area and reaction sites. To ensure that the two-electron oxygen reduction reaction (2e-ORR) at the right cathode produces hydrogen peroxide rather than the four-electron oxygen reduction reaction (4e-ORR) producing water, a carbon-based material with a 6% nitrogen content is loaded into the GDE catalytic layer. The N-C bond structure results in a high barrier to O-O bond breakage due to the perpendicular binding of oxygen molecules to the catalyst surface, leading to higher product selectivity for the 2e-ORR. A specific nitrogen content isolates the surrounding triple hollow sites into individual N atoms, effectively preventing the O-O from breaking to form an O· intermediate and producing H2O.

[0057] The positive electrode of the battery 11 is connected to the anode reaction chamber 102, and the negative electrode of the battery 11 is connected to the left cathode reaction chamber 101 and the right cathode reaction chamber 103. In another embodiment, the positive electrode of the battery 11 is connected to the anode 12. The negative electrode of the battery 11 is connected to the left cathode 14 and the right cathode 15, respectively. The multiple electrode rods in each reaction chamber are connected in series by wires.

[0058] The anode reaction chamber 102 is provided with a wastewater inlet pipe 19. The outlet pipe of the anode reaction chamber 102 is connected to the inlet pipe of the MBR chamber 2 through the MBR inlet pipe 21, and the return pipe of the MBR chamber 2 is connected to the mud supply pipe of the anode reaction chamber 102 through the MBR return pipe 22.

[0059] More than two groups of membrane modules are provided in the MBR chamber 2, and an aerator 172 is provided below the membrane modules.

[0060] The treated wastewater pipe of the MBR chamber 2 is connected to the water inlet pipe of the intermediate pool 4 through the intermediate pool inlet pipe 23, and the treated wastewater pipe of the MBR chamber 2 is connected to the water inlet pipe of the Fenton-like pool 3 through the MBR Fenton inlet pipe 24.

[0061] The hydrogen peroxide outlet pipe of the right cathode reaction chamber 103 is connected to the hydrogen peroxide inlet pipe of the Fenton-like tank 3 through the hydrogen peroxide delivery pipeline 16, and the sludge outlet pipe of the left cathode reaction chamber 101 is connected to the sludge recycling pipe of the Fenton-like tank 3 through the sludge regeneration and recycling pipeline 31.

[0062] The Fenton-like pool 3 is provided with an outlet pipe 33. An α-FeooH particle layer 32 is provided in the middle of the Fenton-like pool 3. The mud outlet pipe of the Fenton-like pool 3 is connected to the mud inlet pipe of the intermediate pool 4 through the intermediate pool mud inlet pipe 41.

[0063] Another object of the present invention is to provide a method for resource-based treatment of organic wastewater based on electrochemical microbial and biochemical coupling, characterized in that the method comprises the following steps:

[0064] Step 1: pumping the organic wastewater into the anode reaction chamber 102 of the electro-biochemical three-chamber 1 through the water inlet pipe 19;

[0065] Step 2: In the anode reaction chamber 102, organic wastewater and muddy water from the MBR chamber 2 are received. At the same time, organic pollutants in the organic wastewater easily lose electrons at the anode 12, undergoing an oxidation reaction. Combined with the biological synergistic effect of the anode external composite filler layer 13, they are initially removed and degraded under the effects of oxidation, biochemistry, and adsorption. Under the action of the proton membrane 18, water molecules and some cations in the organic wastewater enter the left cathode reaction chamber 101 and the right cathode reaction chamber 103 on both sides, causing hydrogen ions in the left cathode reaction chamber 101 and the right cathode reaction chamber 103 to accumulate and make the solution slightly acidic. After being treated in the anode reaction chamber 102, the organic wastewater enters the MBR chamber 2 through the MBR water inlet pipe 21.

[0066] The left cathode reaction chamber 101 receives water molecules and some cations from the anode reaction chamber 102, as well as muddy water pumped into the intermediate tank 4. Under the action of iron-reducing bacteria and slightly acidic conditions, the iron-reducing bacteria decompose organic matter in an anaerobic environment to obtain electrons, converting the trivalent iron ions in the iron sludge into divalent iron ions. The sludge is then connected to the sludge recycling pipe of the Fenton-like tank 3 through the sludge regeneration and recycling pipeline 31, providing a reducing agent for the Fenton tank.

[0067] In the right cathode reaction chamber 103, dissolved oxygen and escaped oxygen are provided by a microporous aerator 171. The right cathode 15 is a gas diffusion electrode. Under the catalysis of nitrogen-carbon-based materials and slightly acidic conditions, oxygen undergoes a two-electron oxygen reduction reaction to produce hydrogen peroxide. A certain concentration of hydrogen peroxide produced in the right cathode reaction chamber 103 enters the Fenton-like cell 3 through the hydrogen peroxide delivery pipeline 16, providing an oxidant for the Fenton reaction.

[0068] Step 3: In the MBR chamber 2, wastewater from the anode reaction chamber 102 is received. There are multiple membrane modules in the MBR chamber 2. The wastewater undergoes membrane biological reaction under the membrane modules and aeration conditions to further biodegrade.

[0069] The return pipe of the MBR chamber 2 is connected to the mud supply pipe of the anode reaction chamber 102 through the MBR return pipe 22;

[0070] The effluent branch of the MBR chamber 2 flows through the MBR Fenton inlet pipe 24 to the Fenton-like tank 3 for deep organic matter oxidation and decomposition. The wastewater in the Fenton-like tank 3 undergoes Fenton reaction with a reaction pH range of 5-6. The reaction effluent is discharged through the effluent pipe 33, and the iron sludge produced by the reaction flows into the intermediate tank 4 through the intermediate tank sludge inlet pipe 41.

[0071] The other branch of the effluent from the MBR chamber 2 flows into the intermediate tank 4 through the intermediate tank inlet pipe 23, so that the sludge in the intermediate tank 4 does not dry out and blockage occurs, and at the same time serves as a carbon source for the iron-reducing bacteria in the left cathode reaction chamber 101;

[0072] Step 4: The intermediate tank 4 receives the iron sludge from the Fenton-like tank 3 reaction and the effluent from the MBR chamber 2; the iron sludge and the effluent from the MBR chamber 2 are in the intermediate tank 4, and the remaining hydrogen peroxide in the iron sludge oxidizes the pollutants, reducing the dissolved oxygen in the iron sludge liquid, and then is circulated through the intermediate tank sludge outlet pipeline 42 and pumped into the left cathode reaction chamber 101;

[0073] Step 5, in the Fenton-like tank 3, hydrogen peroxide from the right cathode reaction chamber 103, wastewater from the MBR chamber 2, and sludge from the left cathode reaction chamber 101 are received; at the initial stage of the reaction start-up of the Fenton-like tank 3, ferrous sulfate solution is added; after normal startup, the Fenton oxidant comes from the hydrogen peroxide in the cathode reaction chamber 103, and the Fenton reductant comes from the divalent iron ions in the sludge in the left cathode reaction chamber 101. The wastewater undergoes Fenton reaction in the Fenton-like tank 3 under the action of hydrogen peroxide and divalent iron ions; the reacted iron sludge is pumped into the intermediate tank 4, and the reacted wastewater is discharged from the outlet pipe 33.

[0074] The mud outlet pipe of the intermediate tank 4 is connected to the mud inlet pipe of the left cathode reaction chamber 101 through the intermediate tank mud outlet pipeline 42. The muddy water has a certain residence time in the intermediate tank, which can eliminate the dissolved oxygen brought out by the MBR chamber effluent, which is beneficial to the iron mud regeneration reaction in the left cathode reaction chamber.

[0075] The effluent from the electro-biochemical three-chamber 1 enters the MBR tank 2 for further biochemical degradation. The effluent from the MBR tank 2 enters the Fenton-like tank 3. A branch is provided for the effluent from the MBR tank 2 to flow to the intermediate tank 4, which then flows back to the left cathode reaction chamber 101 of the electro-biochemical three-chamber 1. This ensures that the iron-reducing bacteria in the left cathode reaction chamber 101 have the required carbon source and sufficient electrolytes for the electrochemical reaction. The intermediate tank 4 also prevents excessive dissolved oxygen in the effluent from the MBR tank 2, which could damage the anaerobic environment in the left cathode reaction chamber 103.

[0076] After treatment in MBR tank 2, wastewater enters Fenton-like reactor 3, where the effluent is discharged through effluent pipe 33. Iron-containing sludge from Fenton-like reactor 3 is discharged into intermediate tank 4 to prevent the sludge from carrying over residual hydrogen peroxide from the Fenton-like reactor 3 reaction and directly entering the bacterial strains in left cathode reaction chamber 101. The residual hydrogen peroxide utilizes its oxidizing properties to oxidize pollutants in intermediate tank 4, eliminating the effects of hydrogen peroxide on iron-reducing bacteria.

[0077] At the initial stage of the Fenton-like tank 3 reaction, a small amount of ferrous sulfate solution needs to be added. After the entire device is started normally, the Fenton oxidant hydrogen peroxide comes from the homemade right cathode reaction chamber 103, and the Fenton catalyst Fe2+ comes from the reduction product of iron-reducing bacteria at the left cathode 14. The entire Fenton-like reaction process can be achieved without the addition of external reagents, and the sludge generated by the entire Fenton-like process is not discharged.

[0078] An α-FeOOH particle layer 32 is provided in the Fenton-like cell 3. The α-FeOOH particles are doped with a certain amount of C3N4, which can increase the hole sites of the catalyst and the mobility of electrons, thereby ensuring the catalytic activity of iron ions on hydrogen peroxide in the Fenton reaction, broadening the pH range of the reaction, and ensuring the reaction amount of hydroxyl radicals. At the same time, the C3N4 and iron base in the α-FeOOH particles construct a micro-electric field, and the oxidized pollutant intermediate R· moves in a direction to form an electron-deficient center. The redox property of R· is utilized to convert HO2· into hydroxyl radicals, thereby increasing the utilization efficiency of hydrogen peroxide by 1 times. Therefore, the Fenton-like cell uses an α-FeooH catalyst loaded with C3N4 particles to form an organic electron-deficient center, and the reaction pH can be widened from 2-3 to 2-6, thereby increasing the utilization efficiency of hydrogen peroxide by 1 times.

[0079] Organic wastewater is pumped into the anode reaction chamber 102 of the electro-biochemical three-chamber 1 through the water inlet pipe 19. Under the action of the proton membrane 18, water molecules and some cations enter the left cathode reaction chamber 101 and the right cathode reaction chamber 103 on both sides. Since H+ ions can unidirectionally penetrate the proton membrane 18, hydrogen ions accumulate in the left cathode reaction chamber 101 and the right cathode reaction chamber 103 on the left and right sides, making the solution slightly acidic. The weak acid condition can promote the dissolution of trivalent iron ions in the left cathode reaction chamber 101 and the preparation of hydrogen peroxide in the right cathode reaction chamber 103. At the same time, organic pollutants in the organic wastewater easily lose electrons at the anode 12, undergoing an oxidation reaction. Combined with the biological synergistic effect of the anode external composite filler layer 13, they are initially removed and degraded under the effects of oxidation, biochemistry and adsorption.

[0080] After being treated in the anode reaction chamber 102 of the electro-biochemical three-chamber 1, the organic wastewater enters the MBR chamber 2 through the MBR inlet pipe 21, where smaller molecular pollutants in the organic wastewater are further degraded. A branch of the effluent from the MBR chamber 2 flows through the MBR Fenton inlet pipe 24 to the Fenton-like tank 3 for deep organic matter oxidation and decomposition. The wastewater in the Fenton-like tank 3 undergoes a Fenton reaction with a pH range of 5-6. The reaction effluent is discharged through the effluent pipe 33, and the reacted iron sludge flows into the intermediate tank 4 through the intermediate tank inlet pipe 41. The iron sludge stays in the intermediate tank 4 for a period of time, which can reduce the dissolved oxygen in the iron sludge liquid to 0-0.2 mg / L. The sludge is then circulated through the intermediate tank outlet pipe 42 and pumped into the left cathode reaction chamber 101 of the electro-biochemical three-chamber 1. Under the action of iron-reducing bacteria, the trivalent iron ions in the iron sludge are converted into divalent iron ions, providing a reducing agent for Fenton and realizing sludge resource recovery.

[0081] Another branch of the effluent from the MBR chamber 2 flows into the intermediate tank 4 through the intermediate tank inlet pipe 23, which can prevent the sludge in the intermediate tank 4 from drying up and blocking. It can also serve as a carbon source for the iron-reducing bacteria in the left cathode reaction chamber 101, thereby increasing the number and activity of microorganisms in the left cathode reaction chamber 101.

[0082] In the right cathode reaction chamber 103, the microporous aerator 171 provides sufficient dissolved oxygen and escaped oxygen. The right cathode 15 is a gas diffusion electrode. Under the catalysis of the carbon-based material containing 6% nitrogen, oxygen undergoes a two-electron oxygen reduction reaction to produce hydrogen peroxide. The reaction equation is as follows:

[0083] 2H + +O2+2e - →H2O2 (1)

[0084] 2H2O+2e - +O2→2H2O2 (2)

[0085] Through the above reaction, hydrogen peroxide of a certain concentration is generated in the right cathode reaction chamber 103 and enters the Fenton-like cell 3 through the hydrogen peroxide delivery pipeline 16, providing oxidant for Fenton, realizing a process route in which the device is self-generated without adding external reagents.

[0086] The right cathode 15 uses a porous three-dimensional gas diffusion electrode, and the electrode catalyst layer is a carbon-based material loaded with 6% nitrogen content, which promotes the two-electron oxygen reduction reaction (2e-ORR), produces a high concentration of H2O2, and provides a source of Fenton's oxidant H2O2. The iron-reducing bacteria in the left cathode 14 use the Fe3+ sludge produced by the Fenton-like tank as a reaction substrate and the organic matter in the MBR chamber effluent as a carbon source, providing a source of Fenton's reductant Fe2+. The intermediate tank 4 can eliminate the adverse effects of residual H2O2 and DO in the effluent of the MBR unit on the microorganisms at the left cathode. The resource recovery treatment device can degrade organic wastewater pollutants, regenerate Fenton reagents, and recycle Fenton sludge, realizing the resource recovery treatment of organic wastewater in an integrated manner.

[0087] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An organic wastewater treatment system based on electrochemical microorganism and biochemical coupling, characterized by: The invention comprises an electro-biochemical three-chamber (1), an MBR chamber (2), a Fenton-like cell (3), an intermediate cell (4) and a battery (11), wherein: The electrobiochemical three-chamber (1) comprises a left cathode reaction chamber (101), an anode reaction chamber (102) and a right cathode reaction chamber (103) which are sequentially connected from left to right; the positive electrode of the battery (11) is connected to the anode reaction chamber (102), and the negative electrode of the battery (11) is connected to the left cathode reaction chamber (101) and the right cathode reaction chamber (103) respectively; a wastewater inlet pipeline (19) is provided on the anode reaction chamber (102); The anode reaction chamber (102) is used to initially remove and degrade the organic wastewater and the muddy water from the MBR chamber (2) by oxidation reaction; under the action of the proton membrane (18), water molecules and some cations of the organic wastewater enter the left cathode reaction chamber (101) and the right cathode reaction chamber (103) on both sides; the organic wastewater enters the MBR chamber (2) after being treated in the anode reaction chamber (102); The left cathode reaction chamber (101) is used for the water molecules and part of the cations from the anode reaction chamber (102) and the muddy water pumped into the middle tank (4); under the action of iron-reducing bacteria and slightly acidic conditions, the iron-reducing bacteria decompose organic matter in an anaerobic environment to obtain electrons, and convert the trivalent iron ions in the iron sludge into divalent iron ions; The right cathode reaction chamber (103) is used for generating hydrogen peroxide by a two-electron oxygen reduction reaction of oxygen under the catalysis of nitrogen-carbon-based materials and slightly acidic conditions; The MBR chamber (2) is used to further biodegrade the wastewater from the anode reaction chamber (102) by membrane biological reaction under membrane modules and aeration conditions; The intermediate tank (4) is used to oxidize pollutants in the iron sludge from the Fenton-like tank (3) and the effluent from the MBR chamber (2) with hydrogen peroxide; The Fenton-like tank (3) is used for the Fenton reaction of hydrogen peroxide from the right cathode reaction chamber (103), wastewater from the MBR chamber (2), and sludge from the left cathode reaction chamber (101).

2. The organic wastewater treatment system based on electrochemical microbial and biochemical coupling according to claim 1 is characterized by: The outlet pipe of the anode reaction chamber (102) is connected to the water inlet pipe of the MBR chamber (2) through the MBR water inlet pipeline (21), and the return pipe of the MBR chamber (2) is connected to the mud supply pipe of the anode reaction chamber (102) through the MBR return pipeline (22); The treated wastewater pipe of the MBR chamber (2) is connected to the water inlet pipe of the intermediate pool (4) through the intermediate pool water inlet pipe (23), and the treated wastewater pipe of the MBR chamber (2) is connected to the water inlet pipe of the Fenton-like pool (3) through the MBR Fenton inlet pipe (24); The hydrogen peroxide outlet pipe of the right cathode reaction chamber (103) is connected to the hydrogen peroxide inlet pipe of the Fenton-like tank (3) through the hydrogen peroxide delivery pipeline (16), and the sludge outlet pipe of the left cathode reaction chamber (101) is connected to the sludge recycling pipe of the Fenton-like tank (3) through the sludge regeneration and recycling pipeline (31); The mud outlet pipe of the Fenton-like pool (3) is connected to the mud inlet pipe of the intermediate pool (4) via the intermediate pool mud inlet pipeline (41); The mud outlet pipe of the intermediate tank (4) is connected to the mud inlet pipe of the left cathode reaction chamber (101) via the intermediate tank mud outlet pipeline (42).

3. The organic wastewater treatment system based on electrochemical microbial and biochemical coupling according to claim 2 is characterized by: An iron-reducing bacteria activated sludge layer and a left cathode (14) are arranged in the left cathode reaction chamber (101); the lower part of the left cathode (14) is inserted into the iron-reducing bacteria activated sludge layer; the left cathode (14) adopts a carbon fiber-coated graphene structure, and a combined filler layer (13) is arranged on the surface of the carbon fiber-coated graphene structure; the negative electrode of the battery (11) is connected to the left cathode (14).

4. The organic wastewater treatment system based on electrochemical microbial and biochemical coupling according to claim 3 is characterized by: An anaerobic activated sludge layer and an anode (12) are arranged in the anode reaction chamber (102); the anaerobic activated sludge layer is inserted into the lower part of the anode (12); the anode (12) adopts a carbon fiber-coated graphene structure, and a combined filler layer (13) is arranged on the surface of the carbon fiber-coated graphene structure; the positive electrode of the battery (11) is connected to the anode (12).

5. The organic wastewater treatment system based on electrochemical microbial and biochemical coupling according to claim 4 is characterized by: The right cathode reaction chamber (103) is provided with a right cathode (15) and an aerator (171), wherein the right cathode (15) is a nitrogen-containing carbon-based material-supported gas diffusion electrode, and the right cathode (15) is located above the aerator (171); The negative electrode of the battery (11) is connected to the right cathode (15).

6. The organic wastewater treatment system based on electrochemical microbial and biochemical coupling according to claim 5 is characterized by: More than two groups of membrane modules are arranged in the MBR chamber (2), and a second aerator (172) is arranged below the membrane modules.

7. The organic wastewater treatment system based on electrochemical microbial and biochemical coupling according to claim 6 is characterized by: The left cathode reaction chamber (101), the anode reaction chamber (102) and the right cathode reaction chamber (103) are separated by a proton membrane (18).

8. The organic wastewater treatment system based on electrochemical microbial and biochemical coupling according to claim 7 is characterized by: The Fenton-like pool (3) is provided with a water outlet pipeline (33); and an α-FeooH particle layer (32) is provided in the Fenton-like pool (3).

9. The organic wastewater treatment system based on electrochemical microbial and biochemical coupling according to claim 8 is characterized by: The pH of the left cathode reaction chamber (101) is controlled at 5-6.

5.

10. A method for resource treatment of organic wastewater based on electrochemical microorganisms and biochemical coupling, characterized in that: The organic wastewater treatment system based on electrochemical microorganism and biochemical coupling according to any one of claims 1 to 8 comprises the following steps: Step 1, pumping the organic wastewater into the anode reaction chamber (102) of the electro-biochemical three-chamber (1) through the water inlet pipeline (19); Step 2, in the anode reaction chamber (102), organic wastewater and muddy water from the MBR chamber (2) are received, and at the same time, organic pollutants in the organic wastewater are easily lost electrons at the anode (12), and an oxidation reaction occurs. In addition, the organic pollutants in the organic wastewater are initially removed and degraded under the action of oxidation, biochemistry and adsorption due to the biological synergistic effect of the anode external composite filler layer (13); under the action of the proton membrane (18), water molecules and part of the cations in the organic wastewater enter the left cathode reaction chamber (101) and the right cathode reaction chamber (103) on both sides, so that hydrogen ions in the left cathode reaction chamber (101) and the right cathode reaction chamber (103) gather and make the solution slightly acidic; after being treated in the anode reaction chamber (102), the organic wastewater enters the MBR chamber (2) through the MBR water inlet pipeline (21); The left cathode reaction chamber (101) receives water molecules and part of the cations from the anode reaction chamber (102) and the muddy water pumped into the intermediate tank (4); under the action of iron-reducing bacteria and slightly acidic conditions, the iron-reducing bacteria decompose organic matter in an anaerobic environment to obtain electrons, converting the trivalent iron ions in the iron sludge into divalent iron ions, which are connected to the sludge recycling pipe of the Fenton-like tank (3) through the sludge regeneration and recycling pipeline (31), thereby providing a reducing agent for Fenton; In the right cathode reaction chamber (103), dissolved oxygen and escaped oxygen are provided by a microporous aerator (171), and the right cathode (15) is a gas diffusion electrode. Under the catalysis of nitrogen-carbon-based materials and slightly acidic conditions, oxygen undergoes a two-electron oxygen reduction reaction to obtain hydrogen peroxide; hydrogen peroxide of a certain concentration generated in the right cathode reaction chamber (103) enters the Fenton-like tank (3) through a hydrogen peroxide delivery pipeline (16) to provide an oxidant for Fenton; Step 3, in the MBR chamber (2), wastewater from the anode reaction chamber (102) is received. There are multiple groups of membrane modules in the MBR chamber (2), and the wastewater undergoes membrane biological reaction under the membrane modules and aeration conditions to further biodegrade; The return pipe of the MBR chamber (2) is connected to the mud supply pipe of the anode reaction chamber (102) through the MBR return pipeline (22); The effluent branch of the MBR chamber (2) flows to the Fenton-like tank (3) through the MBR Fenton inlet pipe (24) for deep oxidation and decomposition of organic matter. The wastewater in the Fenton-like tank (3) undergoes a Fenton reaction with a pH range of 5-6. The reaction effluent is connected to the effluent pipe (33) for discharge, and the iron mud produced by the reaction flows into the intermediate tank (4) through the intermediate tank mud inlet pipe (41); Another branch of the effluent from the MBR chamber (2) flows into the intermediate tank (4) through the intermediate tank inlet pipe (23), so that the sludge in the intermediate tank (4) does not dry out and blockage occurs, and at the same time serves as a carbon source for the iron-reducing bacteria in the left cathode reaction chamber (101); Step 4, the intermediate tank (4) receives the iron sludge from the Fenton-like tank (3) reaction and the effluent from the MBR chamber (2); the iron sludge and the effluent from the MBR chamber (2) are in the intermediate tank (4), and the remaining hydrogen peroxide in the iron sludge oxidizes the pollutants to reduce the dissolved oxygen in the iron sludge liquid, and then is circulated and pumped into the left cathode reaction chamber (101) through the intermediate tank sludge outlet pipeline (42); Step 5, in the Fenton-like tank (3), hydrogen peroxide from the right cathode reaction chamber (103), wastewater from the MBR chamber (2), and sludge from the left cathode reaction chamber (101) are received; at the initial start-up of the reaction of the Fenton-like tank (3), ferrous sulfate solution is added; after normal start-up, the Fenton oxidant comes from the hydrogen peroxide in the cathode reaction chamber (103), and the Fenton reductant comes from the divalent iron ions in the sludge in the left cathode reaction chamber (101), and the wastewater undergoes a Fenton reaction in the Fenton-like tank (3) under the action of the hydrogen peroxide and the divalent iron ions; the iron sludge after the reaction is pumped into the middle tank (4), and the wastewater after the reaction is discharged from the outlet pipe (33).

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