Electrocatalytic biological denitrification system and denitrification method using composite hollow fiber membrane plated with ruthenium electrode

Abstract

The application discloses a kind of hollow fiber membrane of plating ruthenium electrode composite electrocatalysis biological denitrification system and denitrification method, its characteristics are system includes: setting on double-chamber UASB reactor anode / cathode chamber, and composite biological electrode in chamber, the composite biological electrode adopts plating ruthenium iridium titanium mesh barrel outer wrapping carbon felt as cathode, it is equipped with hollow fiber membrane separation sludge in its barrel;Plating ruthenium iridium titanium mesh outer wrapping carbon felt is used as anode, and electric active bacteria pass through anaerobic ammonia oxidation to produce nitrogen gas / nitrate, and ammonia nitrogen is electrochemically oxidized to nitrite, anode nitrogen gas enters cathode to strengthen mass transfer, and cathode nitrite is circulated and utilized to anode, realize nitrogen efficient conversion and removal.The application has the advantages of nitrogen efficient conversion and removal compared with prior art, utilizes electric active microorganism to degrade pre-degradation substrate to synthesize N2 and two electrode additional electrochemical effect to reduce hollow fiber membrane pollution, reduce membrane loss, system structure is simple, maintenance is convenient, with good use prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bio-electrocatalytic membrane reaction devices, in particular to an electrocatalytic biological denitrification system of a ruthenium-plated electrode composite hollow fiber membrane and a denitrification method thereof. BACKGROUND

[0002] The nitrification-denitrification system in the traditional denitrification process has the disadvantages of low denitrification efficiency and large energy consumption. Therefore, the patent "Wastewater treatment method and system based on anaerobic ammonia oxidation reactor" (application publication number CN117923657A, application publication date 2024.04.26) proposes a reactor based on anaerobic ammonia oxidation. Compared with the traditional nitrification-denitrification system, the denitrification efficiency is improved, but there are disadvantages such as slow growth of AnAOB, low activity, and generation of nitrate byproducts in the reaction process. Moreover, the actual wastewater cannot meet the high-concentration NO2 2- -N environment required by Anammox, resulting in low removal efficiency. Bio-electrocatalytic technology can enrich the electrode surface with electroactive microbial films, degrade pollutants, and promote the secretion of EPS by microorganisms to form a three-dimensional bridging matrix with metal ions in the system, allowing AnGS particles to be refined. Studies have shown that AnAOB has extracellular electron transfer capability, so applying an appropriate voltage can enhance biological ammonia oxidation and nitrate reduction capabilities, and can benefit sludge granulation and increase system stability.

[0003] Membrane separation reflux technology is used in the sludge treatment process, mainly using small-pore membranes to intercept sludge and macromolecular substances. The Chinese patent "Hollow fiber membrane high-efficiency denitrification and decarbonization wastewater treatment equipment" (application publication number CN115636528A, application publication date 2023.01.24) proposes that water and small-molecule substances that can pass through the membrane are separated from the sludge solution under pressure driving, which not only allows for reprocessing of wastewater but also enables recycling. Although membrane separation technology for sludge treatment has the advantages of small footprint, beneficial microbial attachment, and good effluent quality, the technology has more colloids and membrane pollutants in the sludge mixed solution, which causes severe membrane pollution. Severe membrane pollution can lead to shorter membrane operation cycles and increased cleaning frequency, resulting in further increases in operating costs, which severely restricts the further use of membrane separation technology for sludge treatment. Studies have shown that by increasing the electric field during the operation of the membrane bioreactor, the membrane assembly becomes negatively charged, and the main membrane pollutants (proteins, colloids, etc.) are negatively charged, which can slow down and control membrane pollution. Moreover, the use of electrode electrocoagulation can improve the effluent quality.

[0004] In summary, the existing technology of electro-catalytic coupling membrane device, the enhanced nitrogen removal system and the method for rapidly improving the total nitrogen removal load are all completed in a high concentration of nitrite environment, which is obviously not ideal in practical application. In the current research on the optimization of anaerobic ammonia oxidation reaction under low concentration of nitrite, the total nitrogen removal rate still needs to be improved, and it cannot break through the limitation of traditional anaerobic ammonia oxidation. In addition, membrane fouling is also a big problem. Therefore, in order to realize the enhancement of the nitrogen removal system and the rapid improvement of the total nitrogen removal load under the environment of low concentration of NO2 2- -N, it is necessary to propose an effective method for strengthening the nitrogen removal reaction. SUMMARY

[0005] The purpose of the present application is to provide a ruthenium electrode composite hollow fiber membrane electro-catalytic biological nitrogen removal system and a nitrogen removal method to overcome the shortcomings of the prior art. The electro-catalytic biological nitrogen removal system adopts a double-chamber UASB reactor separated by a porous filter plate. The anode / cathode chamber of the electro-catalytic biological nitrogen removal system adopts a ruthenium-iridium-titanium mesh and conductive carbon felt. The electroactive bacteria produce nitrogen gas / nitrate through anaerobic ammonia oxidation, and the ammonia nitrogen is electrochemically oxidized to nitrite. The cathode is combined with a ruthenium-iridium-titanium mesh barrel and carbon felt, and the nitrate is reduced to nitrite. The cathode is provided with a hollow fiber membrane to separate the sludge, and a direct current power supply is used to drive the reaction. The anode nitrogen gas enters the cathode to strengthen the mass transfer, and the cathode nitrite flows back to the anode for recycling. The system couples electrochemistry and biology to form an ammonia nitrogen oxidation-nitrate reduction synergistic path, optimizes the electron transfer efficiency through electrode structure, realizes efficient conversion and removal of nitrogen, and has simple system structure, good nitrogen removal effect and good application prospect.

[0006] The technical scheme of the present application is as follows: a kind of electro-catalytic biological denitrification system of composite hollow fiber membrane of ruthenium electrode, its characteristics are as follows: the electro-catalytic biological denitrification system includes: porous filter plate separated anode chamber and cathode chamber of double chamber UASB reactor, hollow fiber membrane, direct current power supply, reflux peristaltic pump, water inlet peristaltic pump and water outlet peristaltic pump, anode adopts ruthenium plated iridium titanium mesh and conductive carbon felt, cathode adopts ruthenium plated iridium titanium mesh barrel and carbon felt, the anode is the composite biological electrode arranged in anode chamber, which is composed of ruthenium plated iridium spiral blade titanium alloy mesh and ruthenium plated iridium titanium alloy rod and anode conductive carbon felt wrapped in the periphery of titanium alloy mesh;The cathode is the composite biological electrode arranged in cathode chamber, which is composed of ruthenium plated iridium titanium alloy mesh barrel and cathode conductive carbon felt fixed on the periphery thereof;The hollow fiber membrane is arranged in the cathode composite biological electrode and is used to separate sludge and small molecule substances;The direct current power supply is connected with the anode composite biological electrode and the cathode composite biological electrode by anode power supply port and cathode power supply port respectively using titanium wire binding, and constant potential is provided to drive electrochemical reaction;The nitrogen generated in the anode chamber enters the cathode chamber through the porous filter plate, and the nitrogen is collected by soft tube sleeve to nitrogen gas collecting bag at the cathode gas outlet, and the nitrogen is pumped in by using cathode gas internal circulation pump;The nitrite generated in the cathode chamber is circulated to the anode chamber by reflux peristaltic pump;The anode conductive carbon felt loads electroactive functional bacteria to generate nitrogen and nitrate by anaerobic ammonia oxidation reaction, and directly oxidize ammonia nitrogen to generate nitrite by anode electrochemical action;The cathode conductive carbon felt loads electroactive functional bacteria to reduce the nitrate transmitted by the anode to nitrite;The water inlet peristaltic pump is connected to the anode water inlet port of the double chamber UASB reactor by soft tube, and is used to transport pre-degradation substrate into the double chamber UASB reactor, and the liquid circulation pump is connected to the anode water outlet port by soft tube, and is used to circulate part of the anode effluent to the anode water inlet port;The water outlet peristaltic pump is connected to the pipe opening arranged at the top of the hollow fiber membrane by soft tube through the cathode water outlet port, and is used to suck the water and small molecule substances separated by the membrane;The hollow fiber membrane is made of polyvinylidene fluoride.

[0007] The ruthenium plated iridium spiral blade titanium alloy mesh and the ruthenium plated iridium titanium alloy rod are arranged in the center of the anode composite biological electrode;The anode conductive carbon felt is fixed on the periphery of the ruthenium plated iridium spiral blade titanium alloy mesh by titanium wire.

[0008] The ruthenium plated iridium titanium alloy mesh barrel and the hollow fiber membrane are arranged in the center of the cathode composite biological electrode;The cathode conductive carbon felt is fixed on the periphery of the ruthenium plated iridium titanium alloy mesh barrel by titanium wire.

[0009] The porous filter plate is vertically arranged in the middle of the double chamber UASB reactor;The surface of the porous filter plate is uniformly distributed with hydrophobic micropores, which are used to block the sludge migration between the anode chamber and the cathode chamber and allow one-way gas permeation.

[0010] The application discloses a denitrification method of an electro-catalytic biological denitrification system of a composite hollow fiber membrane with a ruthenium plating electrode, and has the characteristics that the computer terminal device and the set operation program are used to realize automatic operation of the electro-catalytic biological denitrification of the composite hollow fiber membrane with the ruthenium plating electrode, and the method comprises the following steps.

[0011] 1) the pre-degradation substrate is transported to the anode chamber of the double-chamber UASB reactor, and the anaerobic ammonia oxidation reaction is carried out through the electrically active functional bacteria loaded on the anode composite biological electrode, so that nitrogen and nitrate are generated, and the anode electrochemical action is used to directly oxidize ammonia nitrogen to generate nitrite;

[0012] 2) the nitrate is input into the cathode chamber, and the electrically active functional bacteria loaded on the cathode composite biological electrode are used to reduce the nitrate into nitrite;

[0013] 3) the sludge and small molecule substances in the cathode chamber are separated through the hollow fiber membrane;

[0014] 4) a constant potential is applied to the anode composite biological electrode and the cathode composite biological electrode, and the electrochemical reaction is driven;

[0015] 5) the nitrogen generated in the anode chamber is introduced into the cathode chamber through the porous filter plate, and is collected at a nitrogen gas collecting bag for internal circulation;

[0016] 6) the nitrite generated in the cathode chamber is backflowed to the anode chamber for a circulation reaction, so that the automatic biological denitrification of the electro-catalytic biological denitrification system of the composite hollow fiber membrane with the ruthenium plating electrode is realized.

[0017] The computer terminal device comprises one or more processors and a memory; the memory is coupled with the processor and is used for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors realize the biological denitrification of the electro-catalytic biological denitrification system of the composite hollow fiber membrane with the ruthenium plating electrode.

[0018] Compared with the prior art, the application has the following beneficial technical effects and remarkable technical progress:

[0019] 1) the composite biological electrode has better conductivity than traditional carbon rods and titanium wires, is easier to cause electrochemical oxidation-reduction reaction, is more conducive to electron transfer and microbial adhesion, and is used for oxidizing NH 4+ -N into N2 to achieve the denitrification purpose, and the N2 is circulated by a cathode gas internal circulation pump to reduce the pollution of the hollow fiber membrane.

[0020] 2) the liquid circulation pump increases the time of the pre-degradation substrate staying in the anode, and can make the composite anode further treat the sewage.

[0021] 3) the effluent peristaltic pump can make the sewage backflow, so that the NO22- The backflow to the anode further improves the total nitrogen removal efficiency.

[0022] 4) Coupling electrochemistry and biological action to form an ammonia nitrogen oxidation-nitrate reduction synergistic path, optimizing electron transfer efficiency through electrode structure, realizing efficient conversion and removal of nitrogen.

[0023] 5) Strengthening the anaerobic ammonia oxidation system and rapidly improving the total nitrogen removal load, the system structure is simple, the denitrification effect is good, and has good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the application;

[0025] Figure 2 It is an anode composite biological electrode structure schematic diagram;

[0026] Figure 3 It is a cathode composite biological electrode structure schematic diagram. DETAILED DESCRIPTION

[0027] The application provides a novel Ru-plated electrode composite hollow fiber membrane electrocatalytic biological denitrification system, which applies an electric field to sludge to reduce pollution to the hollow fiber membrane; meanwhile, electrochemistry and membrane separation technology are utilized to accelerate AnAOB growth, improve microbial activity and effluent water quality, and finally add backflow to further enhance sludge denitrification performance.

[0028] Referring to Figure 1 The Ru-plated electrode composite hollow fiber membrane electrocatalytic biological denitrification system of the application comprises: a nitrogen gas collection bag 1, a hollow fiber membrane 2, a cathode gas internal circulation pump 3, a cathode conductive carbon felt 4, a cathode composite biological electrode 5, an anode composite biological electrode 6, an anode conductive carbon felt 7, a liquid circulation pump 8, a direct current power supply 9, a double-chamber UASB reactor 10, an effluent peristaltic pump 11, a backflow peristaltic pump 12, an influent peristaltic pump 13, a porous filter plate 14, a membrane pressure gauge 15, a cathode effluent outlet 16, a cathode gas outlet 17, an anode power supply inlet 18, an anode power supply inlet 19, an anode effluent outlet 20, an anode influent inlet 21, a Ru-plated iridium titanium alloy mesh barrel 22, a Ru-plated iridium titanium alloy rod 23, and a Ru-plated iridium spiral blade titanium alloy mesh 24.

[0029] The plated ruthenium electrode composite hollow fiber membrane electro-catalytic biological denitrification system is composed of a double-chamber UASB reactor 10, an anode composite biological electrode 6 and a cathode composite biological electrode 5, and a porous filter 14 is arranged between the anode chamber and the cathode chamber; nitrogen generated in the anode chamber enters the cathode chamber through the porous filter 14 and is collected by a nitrogen gas collecting bag 1, and the nitrogen collected by the nitrogen gas collecting bag 1 is circulated in the cathode chamber by a cathode gas internal circulation pump 3; the anode composite biological electrode 6 is a spiral blade electrode arranged in the anode chamber, which is wrapped by an anode conductive carbon felt 7 and loaded with electrically active functional bacteria, and NH 4+ -N and NO2 2- -N, N2 and NO3 2- -N are directly oxidized by NH 4 + -N under the electrochemical action of the anode, to produce NO3 2- -N and NO2 2— N. Among them, NO2 2- -N can be used by anaerobic ammonia oxidation bacteria again, and NH 4+ -N is removed; the cathode composite biological electrode 5 is a net barrel electrode arranged in the cathode chamber, which is wrapped by a carbon felt and loaded with electrically active functional bacteria, and NO3 2- -N in the wastewater from the anode is reduced to NO2 2- -N by denitrification; the direct current power supply 9 is connected with the anode composite biological electrode 6 and the cathode composite biological electrode 5 through an electric circuit to provide a constant potential and drive the electrode reaction to occur; the outlet of the water inlet peristaltic pump 13 is connected with the anode water inlet 2; the membrane pressure gauge 15 is arranged on the pipeline connected with the cathode water outlet 16 and the water outlet peristaltic pump 11.

[0030] Referring to Figure 2 , the cathode composite biological electrode 5 comprises a hollow fiber membrane 2, a titanium alloy net barrel plated with ruthenium iridium 22 and a cathode conductive carbon felt 4, the hollow fiber membrane 2 is arranged in the titanium alloy net barrel plated with ruthenium iridium 22, and the titanium alloy net barrel plated with ruthenium iridium 22 is wrapped by the cathode conductive carbon felt 4;

[0031] Referring to Figure 3 , the anode composite biological electrode 6 comprises an anode conductive carbon felt 7, a titanium alloy rod plated with ruthenium iridium 23 and a spiral blade titanium alloy net plated with ruthenium iridium 24, a plurality of symmetrically arranged spiral blade titanium alloy nets plated with ruthenium iridium 24 are hung on the titanium alloy rod plated with ruthenium iridium 23, and the spiral blade titanium alloy net plated with ruthenium iridium 24 is wrapped by the anode conductive carbon felt 7.

[0032] The application is further described in detail below with specific examples. It should be noted that the features in each example can be combined with each other, and the steps in each example can be executed in a computer system of a set of executable instructions, and the logical order shown in the flowchart can be different from the order of execution or description herein.

[0033] The application is further described in detail below with specific examples. Embodiment

[0034] Referring to Figure 1 , the embodiment provides a ruthenium-plated electrode composite hollow fiber membrane electro-catalytic biological denitrification system, which comprises an anode chamber and a cathode chamber arranged on a double-chamber UASB reactor 10 and separated by a porous filter plate 14, and an anode composite biological electrode 6 arranged in the anode chamber and a cathode composite biological electrode 5 arranged in the cathode chamber, wherein the double-chamber UASB reactor 10 is an upflow anaerobic sludge bed; the anode composite biological electrode 6 and the cathode composite biological electrode 5 are provided with a constant potential by a direct current power supply 9 to drive an electrochemical reaction.

[0035] The anode composite biological electrode 6 comprises a ruthenium-plated iridium spiral blade titanium alloy net 24 and an anode conductive carbon felt 7 wrapped around the periphery, which is arranged in the anode chamber to load electroactive functional bacteria, generate nitrogen and nitrate by anaerobic ammonia oxidation reaction, and directly oxidize ammonia nitrogen to generate nitrite by anode electrochemical action.

[0036] The cathode composite biological electrode 5 is composed of a hollow fiber membrane 2, a titanium alloy net barrel 22 plated with ruthenium iridium, and a cathode conductive carbon felt 4 fixed to the periphery thereof, which is arranged in the cathode chamber to load electroactive functional bacteria, and the nitrate transferred by the anode is reduced to nitrite; the hollow fiber membrane 2 is arranged inside the cathode composite biological electrode 5 for separating sludge and small molecular substances; the direct current power supply 9 is connected to the anode composite biological electrode 6 and the cathode composite biological electrode 5 by titanium wires through an anode power input port 19 and a cathode power input port 18 respectively, to provide a constant potential to drive the movement of electrons in the double-chamber UASB reactor 10 and promote microbial electron transfer.

[0037] The nitrogen gas generated in the anode chamber enters the cathode chamber through the porous filter plate 14, and is collected by a nitrogen gas collection bag 1 at the cathode gas outlet 17, and is pumped into the cathode chamber for internal circulation by a cathode gas internal circulation pump 3, the generated nitrite is circulated by a reflux peristaltic pump 12 and returned to the anode chamber through the anode water inlet 21 from the cathode water outlet 16 at the top of the cathode chamber for recycling.

[0038] The cathode composite bio-electrode 5 and the anode composite bio-electrode 6 are arranged in the corresponding cathode and anode chambers of the double-chamber UASB reactor 10, and the surface is loaded with electrically active functional bacteria; the porous filter plate 14 is arranged between the anode chamber and the cathode chamber; the hollow fiber membrane 2 is arranged in the cathode chamber of the double-chamber UASB reactor 10 and located inside the cathode composite bio-electrode 5; the anode water outlet 20 at the top of the anode chamber is connected to the anode bottom in the anode chamber through the liquid circulating pump 8 to circulate from the anode water inlet 21; the direct current power supply 9 is connected to the anode composite bio-electrode 6 and the cathode composite bio-electrode 5 through the circuit to provide a constant potential and drive the electrode reaction to occur; and the membrane pressure gauge 15 is connected to the hollow fiber membrane 2 and the water outlet peristaltic pump 11.

[0039] As an embodiment in the present embodiment, the water inlet peristaltic pump 13 is connected to the bottom of the double-chamber UASB reactor 10 through a pipeline to transport the pre-degradation substrate into the double-chamber UASB reactor 10. The liquid circulating pump 8 is connected to the anode water outlet 20 through a hose to circulate part of the anode effluent to the anode water inlet 21.

[0040] Specifically, the water outlet peristaltic pump 11 is connected to the top of the hollow fiber membrane 2 through a pipeline to pump out the small molecular substances and water separated from the sludge from the double-chamber UASB reactor 10.

[0041] As an embodiment in the present embodiment, the hollow fiber membrane 2 is made of polyvinylidene fluoride (PVDF).

[0042] As an embodiment in the present embodiment, the structure of the anode composite bio-electrode 6 comprises:

[0043] The ruthenium-iridium-plated spiral blade titanium alloy mesh 24 and the ruthenium-iridium-plated titanium alloy rod 23 are arranged in the center of the anode composite bio-electrode 6, and the anode conductive carbon felt 7 is fixed to the periphery of the ruthenium-iridium-plated spiral blade titanium alloy mesh 24 through titanium wires.

[0044] Specifically, the anode composite bio-electrode 6 comprises four ruthenium-iridium-plated spiral blade titanium alloy meshes 24 arranged on the ruthenium-iridium-plated titanium alloy rod 23, and the anode conductive carbon felt 7 is fixed to the periphery of the spiral blade titanium mesh 24 through titanium wires respectively.

[0045] As an embodiment in the present embodiment, the structure of the cathode composite bio-electrode 5 comprises:

[0046] The ruthenium-iridium-plated titanium alloy mesh barrel 22 and the hollow fiber membrane 2 are arranged in the center of the cathode composite bio-electrode 5, and the cathode conductive carbon felt 4 is fixed to the periphery of the ruthenium-iridium-plated titanium alloy mesh barrel 22 through titanium wires.

[0047] As an embodiment in the present embodiment, the porous filter plate 14 is vertically arranged in the middle of the double-chamber UASB reactor 10, and the surface of the porous filter plate 14 is uniformly distributed with hydrophobic micropores for blocking the sludge migration between the anode chamber and the cathode chamber and allowing the one-way penetration of gas.

[0048] As an increased embodiment in the present embodiment, the electric carbon felt is made of a material with conductive polymer and has a good three-dimensional structure, and the anode conductive carbon felt 7 and the cathode conductive carbon felt 4 are made of the conductive polymer material with a good three-dimensional structure.

[0049] As an increased embodiment in the present embodiment, the anode composite bioelectrode 6 is made of a titanium alloy-graphite felt plated with ruthenium iridium and loaded with microorganisms, and can utilize NH 4+ -N and NO2 2- -N to generate N2 and NO3 2- -N, and can be directly oxidized to NH 4+ -N to generate NO3 2- -N and NO2 2- -N, and is utilized again by anaerobic ammonia oxidation bacteria, thereby fully removing NH 4+ -N. In addition, the generated N2 can enter the cathode through the porous filter plate 14 to alleviate membrane pollution.

[0050] As an increased embodiment in the present embodiment, the cathode composite bioelectrode 5 is made of a titanium alloy-graphite felt plated with ruthenium iridium and loaded with microorganisms, and can reduce NO3 2- -N to NO2 2- -N by denitrification.

[0051] Based on this, the composite hollow fiber membrane electro-catalytic biological denitrification system provided by the embodiment of the present application has better conductivity than the traditional carbon rod and titanium wire, is more prone to electrochemical oxidation-reduction reaction, is more conducive to electron transfer and microbial adhesion, utilizes electrically active microorganisms and anaerobic ammonia oxidation bacteria to oxidize NH 4+ -N to synthesize N2 to achieve the purpose of denitrification, and circulates N2 through the cathode gas internal circulation pump 3 to reduce the pollution of the hollow fiber membrane. In addition, the liquid circulation pump 8 increases the residence time of the pre-degradation substrate in the anode, so that the composite anode can further denitrify the wastewater; and the effluent peristaltic pump can make the wastewater backflow, so that the NO2 2- -N generated by the cathode reaction flows back to the anode to further improve the total nitrogen removal efficiency.

[0052] The advantages of the present embodiment are illustrated by three experimental cases as follows:

[0053] Experimental case 1:

[0054] Referring to Figure 1 , the culture device uses a 2.5 L double-chamber UASB reactor. Among them, the anode chamber and the cathode chamber are each 1 L, containing a 500 mL top space for biogas collection. The anode and the cathode are connected to a direct current source through an external circuit to provide a required 2.5 V potential.

[0055] Referring to Figures 2-3 , the anode and cathode materials used are both carbon rod electrodes wound with graphite felt. The anode chamber sludge is taken from the anaerobic ammonia oxidation original sludge domesticated by a solid waste laboratory as the inoculated sludge and electrolyte is added; the cathode chamber sludge is taken from the activated sludge of a sewage plant as the inoculated sludge, and the effluent from the lower anode is used as the electrolyte. The N2 internal circulation aeration flow rate is set to 2 L / minute daily, and the aeration time is controlled to 8 h / day. Before the experiment starts, the solution pH in the anode and cathode chambers is adjusted to 7.0 to adapt to the growth of electrically active functional bacteria. At certain intervals, a certain volume of biogas (N2) is taken from the top space of the cathode cavity with a syringe, analyzed by a gas chromatograph equipped with a thermal conductivity detector, and the total nitrogen degradation rate is determined by the national standard method. After the reactor runs for 15 days, the total nitrogen removal rate of the system reaches 69.16%, which is about 38.85% higher than that of the ordinary system.

[0056] Experimental case 2:

[0057] The electrolyte added in the anode and cathode, the preparation of trace solution, and the use method are the same as in experimental case 1, and an anode backflow device is added. A constant potential instrument and other circuit control devices are used to apply a 2.5 V potential to the cathode. The N2 internal circulation aeration flow rate is set to 2 L / minute daily, and the aeration time is controlled to 8 h / day. The enhanced anaerobic ammonia oxidation system and the system for rapidly increasing the total nitrogen removal load provided by the present application, compared with the Anammox system without installing a hollow fiber membrane and without adding backflow, under the same reaction conditions, the total nitrogen removal rate is increased by 16.9% (reached 86.06%), which is about 55.75% higher than that of the ordinary system. At the same time, the backflow in the anode chamber reduces the concentration of pollutants, and after the reaction is completed, the hollow fiber membrane does not appear pollution phenomenon.

[0058] Experimental case 3:

[0059] The electrolyte, trace solution preparation and use method in the cathode and anode of the reactor are the same as those in the experimental case 2, and a cathode backflow device is additionally arranged. A constant potential instrument and other circuit control devices are used to apply a potential of 2.5 V to the cathode. The N2 internal circulation aeration flow rate is set to 2 L / min, the aeration time is controlled to 8 h / day, and the cathode backflow ratio is set to 0.5. Compared with case 2, under the same reaction conditions, the total nitrogen removal rate reaches 94.24%, which is about 63.94% higher than that of the ordinary system, and in the case of low-concentration NO2 2- -N, efficient denitrification is achieved, and the transmembrane pressure difference is only -15 kPa.

[0060] Therefore, the enhanced anaerobic ammonia oxidation system and the system for rapidly increasing the total nitrogen removal load provided in the embodiment have the following beneficial effects:

[0061] 1) Compared with the traditional carbon rod and titanium wire, the composite biological electrode has better conductivity, is more prone to electrochemical oxidation-reduction reaction, degrades and removes nitrogen, and is more conducive to electron transfer and microbial adhesion.

[0062] 2) Compared with the traditional Anammox technology, the system still has a high denitrification rate for low-concentration nitrite nitrogen wastewater, saves cost, is high in energy saving and low in carbon, and achieves the effect of energy recycling.

[0063] 3) The system can utilize electroactive microorganisms to degrade the pre-degradation substrate to synthesize N2 and the electrochemical effect of the two electrodes to reduce hollow fiber membrane pollution, reduce membrane washing frequency, and reduce membrane loss.

[0064] 4) The system has high automation degree, is convenient to install and maintain, can realize long-term stable operation, and has low requirements for operators. Embodiment

[0065] Based on the same overall inventive concept, the application further provides a method for electrocatalytic biological denitrification of a composite hollow fiber membrane with a ruthenium-plated electrode. The method for electrocatalytic biological denitrification of a composite hollow fiber membrane with a ruthenium-plated electrode provided by the application is described as follows, and the method for electrocatalytic biological denitrification of a composite hollow fiber membrane with a ruthenium-plated electrode described below can be correspondingly referred to the system for electrocatalytic biological denitrification of a composite hollow fiber membrane with a ruthenium-plated electrode described above. The method comprises the following steps:

[0066] 1) The pre-degradation substrate is delivered to the anode chamber of the double-chamber UASB reactor 10, and the electroactive functional bacteria loaded on the anode composite biological electrode 6 perform an anaerobic ammonia oxidation reaction to generate nitrogen and nitrate, and at the same time, the anode electrochemical effect directly oxidizes ammonia nitrogen to generate nitrite.

[0067] 2) The nitrate is delivered to the cathode chamber, and the electroactive functional bacteria loaded on the cathode composite biological electrode 5 reduce the nitrate to nitrite;

[0068] 3) Separation of sludge and small molecules in the cathode chamber by hollow fiber membrane 2;

[0069] 4) Application of constant potential to the anode composite bi-electrode 6 and the cathode composite bi-electrode 5 to drive electrochemical reactions;

[0070] 5) Introduction of nitrogen gas generated in the anode chamber into the cathode chamber through the porous filter plate 14, collection at the nitrogen gas collection bag 1 and internal circulation;

[0071] 6) Backflow of nitrite generated in the cathode chamber to the anode chamber for cyclic reaction.

[0072] As an embodiment in the present application, the transport of pre-degradation substrate is achieved by the influent water peristaltic pump 13 connected to the bottom of the double-chamber UASB reactor 10.

[0073] As an embodiment in the present application, the separation of sludge and small molecules is achieved by the effluent water peristaltic pump 11 connected to the top of the hollow fiber membrane 2.

[0074] The above-mentioned embodiment of the method for electro-catalytic biological denitrification of the ruthenium-plated electrode composite hollow fiber membrane comprises: a computer terminal device comprising one or more processors; the processor is coupled to store one or more programs, when the one or more programs are executed by the one or more processors, so that the one or more processors implement a method for electro-catalytic biological denitrification of the ruthenium-plated electrode composite hollow fiber membrane.

[0075] The above, only for the preferred specific embodiments of the present application, but the scope of protection of the present application is not limited to this, any skilled in the art of the technical personnel in the technical range of the present application, can easily think of changes or replacement, should be covered in the scope of protection of the present application. Therefore, the scope of protection of the present application should be subject to the scope of protection of the claims.

Claims

1. An electrocatalytic biological denitrification system using a ruthenium-plated electrode composite hollow fiber membrane, characterized in that, The denitrification system includes an anode chamber and a cathode chamber mounted on a dual-chamber UASB reactor, an anode composite bioelectrode mounted in the anode chamber, and a cathode composite bioelectrode mounted in the cathode chamber. The cathode chamber is equipped with a gas circulation pipe and a liquid circulation pipe. The gas circulation pipe consists of a nitrogen collection bag and a cathode gas internal circulation pump connected by a pipeline. The nitrogen collection bag is connected to the cathode outlet. The cathode gas internal circulation pump pumps the nitrogen collected by the nitrogen collection bag from the bottom of the chamber into the cathode chamber. The liquid circulation pipe consists of a reflux peristaltic pump and a membrane pressure gauge connected by a pipeline. The reflux peristaltic pump pumps the liquid from the cathode chamber into the anode chamber through the anode inlet. The anode chamber is equipped with a return pipeline for a liquid circulation pump; the two ports of the liquid circulation pump are respectively connected to the anode outlet and the anode inlet; the denitrification system is equipped with an inlet peristaltic pump for supplying pre-degraded substrate into the dual-chamber UASB reactor and an outlet peristaltic pump for discharging liquid from the dual-chamber UASB reactor; the inlet of the outlet peristaltic pump is connected to the inlet of the return peristaltic pump; the outlet of the inlet peristaltic pump is connected to the anode inlet; the anode composite bioelectrode and the cathode composite bioelectrode are provided with a constant potential by a DC power supply to drive electron movement within the dual-chamber UASB reactor, while simultaneously promoting microbial electron transfer, thereby achieving electrocatalytic biological denitrification.

2. The electrocatalytic biological denitrification system with ruthenium-plated electrode composite hollow fiber membrane according to claim 1, characterized in that, The dual-chamber UASB reactor is an upflow anaerobic sludge blanket reactor.

3. The electrocatalytic biological denitrification system with a ruthenium-plated electrode composite hollow fiber membrane according to claim 1, characterized in that, The cathode composite bioelectrode consists of a hollow fiber membrane disposed within a ruthenium-iridium plated titanium alloy mesh barrel, with the cathode conductive carbon felt surrounding the ruthenium-iridium plated titanium alloy mesh barrel; the hollow fiber membrane is made of polyvinylidene fluoride.

4. The electrocatalytic biological denitrification system using a ruthenium-plated electrode composite hollow fiber membrane according to claim 1, characterized in that, The anode composite bioelectrode consists of several symmetrically arranged ruthenium-iridium-plated helical blade titanium alloy meshes mounted on a ruthenium-iridium-plated titanium alloy rod, with the anode conductive carbon felt wrapped around the ruthenium-iridium-plated helical blade titanium alloy meshes.

5. The electrocatalytic biological denitrification system with a ruthenium-plated electrode composite hollow fiber membrane according to claim 1, characterized in that, The porous filter plate is provided with uniformly distributed hydrophobic micropores.

6. A denitrification method for an electrocatalytic biological denitrification system using a ruthenium-plated electrode composite hollow fiber membrane as described in claim 1, characterized in that, The automated biological denitrification of the ruthenium-plated electrode composite hollow fiber membrane electrocatalytic biological denitrification system is achieved using computer terminal equipment and a pre-defined operating program. The specific steps include: 1) The pre-degradable matrix is ​​input into the anode chamber of the dual-chamber UASB reactor, and the electroactive functional bacteria loaded on the anode composite bioelectrode carry out an anaerobic ammonia oxidation reaction to generate nitrogen and nitrate. At the same time, ammonia nitrogen is directly oxidized to nitrite through anode electrochemical action. 2) The nitrates generated above are transferred to the cathode chamber, and the electroactive functional bacteria loaded on the cathode composite bioelectrode reduce the nitrates to nitrites; 3) Separate sludge and small molecules in the cathode chamber using a hollow fiber membrane; 4) Apply a constant potential to the anodic and cathode composite bioelectrodes to drive the electrochemical reaction; 5) The nitrogen gas generated in the anode chamber is introduced into the cathode chamber through a porous filter plate; 6) The nitrite generated in the cathode chamber is returned to the anode chamber for recycling reaction to achieve electrocatalytic biological denitrification.

7. The denitrification method of the electrocatalytic biological denitrification system with ruthenium-plated electrode composite hollow fiber membrane according to claim 6, characterized in that, The computer terminal device includes one or more processors and a memory, the memory being coupled to the processors. When one or more programs are executed by one or more processors, the one or more processors enable the automatic biological denitrification of the ruthenium-plated electrode composite hollow fiber membrane electrocatalytic biological denitrification system.

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