System and method for enhancing denitrification performance of hydrogen-based denitrification reactor based on biological sponge

Abstract

The application discloses a system and method for enhancing hydrogen-based denitrification reactor denitrification performance based on a biological sponge body, and comprises a hydrogen-based denitrification reactor, a reactor main body vertically placed, a hollow fiber membrane wire placed in the reactor main body, the hollow fiber membrane wire connected with a membrane tube, the membrane tube connected with H2 and CO2, used for feeding H2 and CO2 into the hollow fiber membrane wire, the lower end of the reactor main body connected with a raw water tank through a water inlet pipe, a reflux pipe connected between one side of the upper end of the reactor main body and the water inlet pipe, the other side of the upper end of the reactor main body connected with a water outlet tank through a water outlet pipe, and a micro multi-layer sponge tightly wrapped around the hollow fiber membrane wire. The application can enhance the denitrification effect of the reactor, promote the efficient and stable removal of nitrate, further increase the contact opportunity of microorganisms and substrates, and improve the utilization efficiency of hydrogen electron donors.

Description

Technical Field

[0001] The present invention relates to a system and method for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on biological sponges, and belongs to the technical field of sewage treatment. Background Art

[0002] Among the existing methods for treating nitrates, biological denitrification uses microorganisms as media and organic or inorganic matter as electron donors to convert nitrates that harm the ecological environment and threaten human health into safe and harmless nitrogen gas as electron acceptors. It has the advantages of being economical and efficient and has always been the main means of treating nitrates.

[0003] However, there are usually insufficient electron donors in water bodies. The additional addition of inorganic electron donors such as elemental sulfur and zero-valent iron will increase the risk of secondary pollution such as hydrogen sulfide and iron ions in the effluent. In contrast, hydrogen autotrophic denitrification, which uses hydrogen as an electron donor, is environmentally friendly and leaves no residue. Hydrogen is transferred to the interior of the reactor through hollow fiber membranes without bubbles, and microorganisms capture trace hydrogen in the environment for autotrophic denitrification. This requires the microorganisms to maintain high activity to fully utilize the hydrogen, but the yield coefficient of hydrogenotrophic denitrifying bacteria is low, the reproduction rate is slow, and the growth environment is demanding. Summary of the Invention

[0004] In response to the problems existing in the above-mentioned prior art, the present invention provides a system and method for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on a biological sponge, which can optimize the growth environment of microorganisms and increase the contact opportunities between microorganisms and substrates, thereby improving the utilization rate of hydrogen electron donors and enhancing the nitrate removal effect.

[0005] In order to achieve the above objectives, the present invention adopts a system based on biological sponge to enhance the denitrification performance of hydrogen-based denitrification reactor, comprising:

[0006] A hydrogen-based denitrification reactor comprises a vertically placed reactor body, wherein hollow fiber membranes are placed in the reactor body, wherein the hollow fiber membranes are connected to membrane tubes, and wherein the membrane tubes are connected to H2 and CO2 for introducing H2 and CO2 into the hollow fiber membranes; wherein the lower end of the reactor body is connected to a raw water tank via an inlet pipe, a reflux pipe is connected between one side of the upper end of the reactor body and the inlet pipe, and the other side of the upper end of the reactor body is connected to a water outlet tank via an outlet pipe;

[0007] Micro multi-layer sponge, the micro multi-layer sponge tightly wraps the hollow fiber membrane, the micro multi-layer sponge is made of PPC modified hydrophilic polyurethane material, with a specific surface area of ​​>4500m 2 / m 3 The number of layers of micro multi-layer sponge filled in the reactor body is not less than 10-12 layers, and the filling volume is not less than 40%-50% of the effective volume of the reactor body.

[0008] As an improvement, a water inlet pump is installed on the water inlet pipe, and a return pump is installed on the return pipe.

[0009] As an improvement, the reflux flow rate of the reflux pipe is 5-50 times the inlet flow rate of the inlet pipe.

[0010] As an improvement, the hollow fiber membrane is made of PVDF, with an inner diameter of 1-3 mm and an outer diameter of 1.5-6 mm.

[0011] As an improvement, the hollow fiber membrane is completely immersed in the suspended sludge in the reactor body, the lateral extension length does not exceed 3 / 5 of the inner diameter of the reactor body, the distance from the bottom of the reactor body is 1 / 7-1 / 8 of the effective water depth, and the rising flow rate of the water flow below the hollow fiber membrane is controlled at 1-2m / h.

[0012] As an improvement, the size of a single sponge in the micro multi-layer sponge is 1*1*1-5*5*5cm.

[0013] As an improvement, the membrane tube is connected to the CO2 gas bag and the H2 gas bag through a tee, and the CO2 gas bag and the H2 gas bag are respectively connected to the gas extrusion water tank, and the gas extrusion water tank is used to feed water into the CO2 gas bag and the H2 gas bag to squeeze the gas into the hollow fiber membrane.

[0014] As an improvement, the pH value in the reactor body is 7.0-9.0, and the temperature is 20-35°C.

[0015] In addition, the present invention also provides a method for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on a biological sponge, and the system for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on a biological sponge comprises the following steps:

[0016] S1. Connect the lower end of the reactor body to the water inlet pipe, which is connected to the raw water tank. Connect one side of the upper end of the reactor body to the reflux pipe, and the lower end of the reflux pipe is connected to the water inlet pipe. Connect the other side of the upper end of the reactor body to the water outlet pipe, which is connected to the water outlet tank. Install hollow fiber membranes in the reactor body, then inoculate sludge, continue to fill the reactor body with micro multi-layer sponges, and insert the micro multi-layer sponges into the gaps inside and around the hollow fiber membranes to achieve tight wrapping of the membranes. The upper ends of the hollow fiber membranes are connected to H2 and CO2 through membrane tubes.

[0017] S2. H2 and CO2 are provided to the hollow fiber membrane and the reactor body, and the nitrate wastewater in the raw water tank is continuously introduced into the hydrogen-based denitrification reactor. At the same time, the raw water in the reactor is refluxed through the reflux pipe. The micro multi-layer sponge tightly wraps the hollow fiber membrane to promote the removal of nitrate in the nitrate wastewater.

[0018] As an improvement, the MLVSS of the inoculated sludge is 3-8 g / L, the concentration of nitrate in the nitrate wastewater is 5-30 mg N / L, the H2 and CO2 feed contents per unit volume of the reactor are 150-800 mL / d, respectively, and H2:CO2=1:1-3:1, the reaction time of the reactor is 8-15 h, the reflux flow rate of the reactor is 5-50 times the inlet flow rate, the pH value of the reactor is 7.0-9.0, and the temperature is 20-35°C.

[0019] Principle of the present invention:

[0020] Using H2 as an electron donor, CO2 as an inorganic carbon source, and hollow fiber membranes as a hydrogen supply, the micro-multi-layered sponge serves as a retention station for micro-hydrogen bubbles and an efficient workspace for the reactive functional bacterial community. On the one hand, the micro-hydrogen bubbles slowly enter the sponge's multi-layered, dense network structure and are stored. They are then captured and utilized by active functional microorganisms that have established themselves on the sponge's surface and within its multiple layers for hydrogen autotrophic denitrification. This increases the microorganisms' access to hydrogen electron donors, avoids hydrogen waste, and enhances the system's denitrification performance. On the other hand, suspended functional bacteria are less likely to capture and utilize gaseous electron donors, which are easily lost and dissipated in water. The retention of micro-hydrogen within the sponge positively encourages more microorganisms to enter the sponge and attach and grow there to complete denitrification. Furthermore, the microbial consumption of the micro-hydrogen within the sponge drives the next batch of diffused micro-hydrogen bubbles into the sponge for storage and utilization, further improving hydrogen utilization efficiency and achieving efficient and stable denitrification. The sponge, microorganisms and micro hydrogen bubbles complement each other and work together to promote the denitrification and denitrification of the system.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The micro-multilayer sponge acts as a retention space station for micro-hydrogen bubbles, absorbing and capturing micro-hydrogen that is extremely easy to lose in the water environment, increasing the residence time of micro-hydrogen in the water environment, and further promoting the contact between micro-hydrogen and related functional bacteria such as hydrogen-trophic denitrifying bacteria, thereby improving the utilization efficiency of hydrogen electron donors, which plays a vital role in optimizing the denitrification and denitrification performance of the system.

[0023] (2) The micro-multi-layer sponge serves as an efficient workroom for the reaction functional bacteria, avoiding the dilemma of suspended microorganisms being difficult to capture and utilize gaseous electron donors that are easily lost and dissipated in the water environment. The multi-layer sponge that stores micro-hydrogen positively promotes the entry of more microorganisms to complete denitrification; the microbial utilization and consumption of micro-hydrogen in the sponge will in turn drive the next batch of diffused micro-hydrogen bubbles to enter the sponge for storage and utilization, thereby achieving efficient and stable denitrification of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the system structure of the present invention;

[0025] Figure 2 The performance comparison of the bio-sponge enhanced hydrogen-based denitrification reactor (R1) of the present invention and the conventional hydrogen-based denitrification reactor (R2) in treating simulated nitrate wastewater (taking the inlet and outlet nitrate concentrations and nitrate removal rates as examples);

[0026] In the figure: 1. Raw water tank, 2. Water outlet tank, 3. Water inlet pipe, 4. Return pipe, 5. Micro multi-layer sponge, 6. Hollow fiber membrane, 7. Reactor body, 8. Membrane tube, 9. CO2 gas bag, 10. H2 gas bag, 11. Gas squeeze water tank, 12. Water outlet pipe. DETAILED DESCRIPTION

[0027] The following embodiments are further descriptions of the present invention to illustrate the technical content of the present invention, but the essential content of the present invention is not limited to the following embodiments. Ordinary technicians in this field can and should know that any simple changes or replacements based on the essential spirit of the present invention should fall within the scope of protection required by the present invention.

[0028] Example 1

[0029] like Figure 1 As shown, a system for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on a biological sponge comprises a hydrogen-based denitrification reactor and a micro multi-layer sponge 5 installed in the hydrogen-based denitrification reactor;

[0030] The hydrogen-based denitrification reactor includes a vertically placed reactor body 7, in which a hollow fiber membrane filament 6 is vertically placed. The hollow fiber membrane filament 6 in this embodiment is U-shaped and suspended in the reactor. The height occupied is relatively small, which makes it easy to achieve full contact between the membrane filament and the suspended sludge; the hollow fiber membrane filament 6 is connected to a membrane tube 8, and the membrane tube 8 is connected to H2 and CO2 for introducing H2 and CO2 into the hollow fiber membrane filament 6;

[0031] The lower end of the reactor body 7 is connected to the raw water tank 1 through the water inlet pipe 3, and the nitrate wastewater in the raw water tank 1 is continuously introduced into the reactor through the water inlet pipe 3; a return pipe 4 is connected between one side of the upper end of the reactor body 7 and the water inlet pipe 3, and the raw water in the reactor is returned to the water inlet pipe 3 through the return pipe 4 and flows into the reactor again through the water inlet pipe 3; the other side of the upper end of the reactor body 7 is connected to the outlet tank 2 through the outlet pipe 12, and the wastewater from which nitrate is removed flows into the outlet tank 2 through the outlet pipe 12;

[0032] The micro multilayer sponge 5 is tightly arranged in the water environment around the hollow fiber membrane 6 and stacked layer by layer. The number of layers of the micro multilayer sponge 5 filled in the reactor body 7 is not less than 10-12 layers, and the filling volume is not less than 40%-50% of the effective volume of the reactor body 7. The micro multilayer sponge 5 is made of PPC modified hydrophilic polyurethane material with a specific surface area of ​​>4500m 2 / m 3 Traditional hydrogen-based denitrification reactors only use membrane components to provide hydrogen for denitrification, relying on the formation of biofilms on hollow fiber membranes and the denitrification activity of suspended sludge. When the sludge activity is low and the amount of hydrogen is small, the formation of biofilms will be slow. At this time, microorganisms cannot use these electron donors in a timely and effective manner, which will lead to the loss of hydrogen bubbles and affect the denitrification effect. The present invention uses a micro multi-layer sponge, which is a multi-layer material with a mesh interior. A plurality of micro multi-layer sponges are used to tightly wrap a hydrogen supply fiber membrane (hollow fiber membrane filament); micro hydrogen bubbles slowly enter the multi-layer dense mesh structure of the sponge and are stored. Their residence in the sponge will positively promote microorganisms to enter the sponge and attach and grow on it; relevant functional microorganisms that have "settled" at multiple levels on the surface and inside of the sponge and have active performance capture and utilize micro hydrogen for hydrogen autotrophic denitrification; the utilization and consumption of micro hydrogen in the sponge by microorganisms will drive the next batch of diffused micro hydrogen bubbles to enter the sponge for storage and utilization, thereby avoiding the waste of hydrogen and improving the utilization efficiency of hydrogen electron donors; the sponge, microorganisms and micro hydrogen bubbles complement each other to promote efficient and stable denitrification of the system.

[0033] The present invention mainly relies on slow-growing hydrogen autotrophic denitrifying bacteria to denitrify. When the operation starts, the system has the same biomass. The denitrification effect mainly depends on the utilization of hydrogen electron donors by microorganisms. The sponge can increase the residence time of microhydrogen in the water environment, which is crucial for denitrification. The relevant functional bacteria in a suspended state are not easy to capture and utilize the gaseous electron donors that are easily lost and dissipated in the water environment. The residence of microhydrogen in the sponge will positively promote the microorganisms to enter the sponge and attach and grow on it to complete denitrification. In addition, the utilization and consumption of microhydrogen in the sponge by microorganisms will promote the next batch of diffused microhydrogen bubbles to enter the sponge and be stored and utilized, further improving the hydrogen utilization efficiency, thereby achieving efficient and stable denitrification of the system. The sponge, microorganisms and microhydrogen bubbles complement each other and play a role in strengthening the denitrification and denitrification of the system.

[0034] As an improvement of the embodiment, a water inlet pump is installed on the water inlet pipe 3, and a reflux pump is installed on the reflux pipe 4. The water inlet pump and the reflux pump ensure smooth water inflow and reflux.

[0035] As an improvement to the embodiment, the hollow fiber membrane filaments 6 are made of PVDF (polyvinylidene fluoride) with an inner diameter of 1-3mm and an outer diameter of 1.5-6mm. The hollow fiber membrane filaments 6 serve as a tool for hydrogen diffusion to ensure the normal progress of hydrogen nutrition denitrification. The hollow fiber membrane filaments 6 must be completely immersed in the suspended sludge inside the reactor body 7 to ensure full contact between the sponge wrapped around the membrane filaments and the microorganisms; the lateral extension length does not exceed 3 / 5 of the inner diameter of the reactor to ensure that there is a certain space for filling the sponge within the extension range of the membrane filaments. At the same time, the distance between the hollow fiber membrane filaments 6 and the bottom of the reactor is maintained at 1 / 7-1 / 8 of the effective water depth, and the rising flow rate of the water flow below the hollow fiber membrane filaments 6 is controlled at 1-2m / h, all to ensure that the water intake and reflux water volume will not cause excessive disturbance to the sponge wrapped around the membrane filaments, and reduce the interference of the flow shear force on the microorganisms in the sponge.

[0036] As an improvement to the embodiment, the size of a single sponge in the micro-multi-layer sponge 5 ranges from 1*1*1 to 5*5*5 cm, and can be a regular or irregular cube shape, such as 1*1*1 cm, 2*2*2 cm, or 3*3*3 cm. Of course, a regular or irregular rectangular parallelepiped shape is also possible. The micro-multi-layer sponges 5 are tightly arranged and stacked layer by layer in the water environment surrounding the hollow fiber membrane filaments 6 to ensure that the micro-hydrogen bubbles can enter a sufficient amount of the micro-multi-layer sponge during the diffusion process, reside, and be utilized, avoiding excessive squeezing and deformation between the micro-hydrogen bubbles. This ensures that the sponge is in a complete shape, which is conducive to the retention of the micro-hydrogen bubbles and the efficient work, growth, and reproduction of the microorganisms. The micro multi-layer sponge 5 serves as a retention space station for micro hydrogen bubbles in the water environment and an efficient working room for the reaction functional bacteria. It increases the residence time of micro hydrogen in the water environment, promotes the contact between micro hydrogen and related functional bacteria such as hydrogen-trophic denitrifying bacteria, and thus improves the utilization efficiency of hydrogen electron donors. At the same time, the retention of micro hydrogen will positively promote more microorganisms to enter the sponge to complete denitrification, and the utilization and consumption of micro hydrogen by microorganisms will push the next batch of diffused micro hydrogen bubbles into the sponge for storage and utilization, thereby enhancing the denitrification and denitrification effect of the system.

[0037] As an improvement of the embodiment, the membrane tube 8 is connected to the CO2 gas bag 9 and the H2 gas bag 10 through a tee, and the CO2 gas bag 9 and the H2 gas bag 10 are respectively connected to the gas extrusion water tank 11. The gas extrusion water tank 11 is used to inject water into the CO2 gas bag 9 and the H2 gas bag 10 to squeeze the gas into the hollow fiber membrane 6, avoiding the use of high-pressure gas cylinders and reducing certain risks; at the same time, the air intake flow rate can be adjusted by the water intake flow rate, and the control is simpler and more convenient.

[0038] Example 2

[0039] Combine Figure 1 、 Figure 2 As shown, a method for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on a biological sponge comprises the following steps:

[0040] S1. Connect the lower end of the reactor body 7 to the water inlet pipe 3, the water inlet pipe 3 is connected to the raw water tank 1, one side of the upper end of the reactor body 7 is connected to the reflux pipe 4, the lower end of the reflux pipe 4 is connected to the water inlet pipe 3, the other side of the upper end of the reactor body 7 is connected to the outlet pipe 12, and the outlet pipe 12 is connected to the outlet tank 2; install the hollow fiber membrane 6 in the reactor body 7, then inoculate the sludge, continue to fill the reactor body 7 with micro multilayer sponges 5, and stuff the micro multilayer sponges 5 into the gaps inside and around the hollow fiber membrane 6 to achieve tight wrapping of the membrane, and the upper end of the hollow fiber membrane 6 is connected to H2 and CO2 through the membrane tube 8;

[0041] S2. H2 and CO2 are supplied to the hollow fiber membrane filaments 6 and the reactor body 7. The nitrate wastewater in the raw water tank 1 is continuously passed into the hydrogen-based denitrification reactor. At the same time, the raw water in the reactor is refluxed through the reflux pipe 4. The micro multi-layer sponge 5 tightly wraps the hollow fiber membrane filaments 6 to promote the removal of nitrate in the nitrate wastewater.

[0042] The MLVSS of the inoculated sludge is 7 g / L, the concentration of nitrate in the nitrate wastewater is 15 mg N / L, the H2 and CO2 feed contents per unit volume of the reactor are 500 mL / d, respectively, the reaction time of the reactor is 12 h, the reflux flow rate of the reactor is 50 times the inlet flow rate, the pH value of the reactor is 7.4-7.8, and the temperature is 28° C. The hollow fiber membrane includes 70 hollow fiber membranes, the hollow fiber membrane is made of PVDF (polyvinylidene fluoride), has an inner diameter of 1.2 mm, and an outer diameter of 2 mm, and the size of a single micro multilayer sponge is 2*2*2 cm;

[0043] The micro-multi-layered sponge tightly encasing the hollow fiber membrane in the reactor provides both a storage space for easily dissipated gaseous electron donors and a highly efficient denitrification workspace and a suitable growth and reproduction platform for hydrogenotrophic denitrifying bacteria. This captures and utilizes micro-hydrogen in the environment while simultaneously pushing the next batch of diffused micro-hydrogen bubbles into the sponge for storage and utilization, thereby improving hydrogen utilization efficiency. Operating under these conditions, the following performance was achieved: a stable nitrate removal rate of 80.76%, approximately 35.05% higher than that of a single hydrogen-based denitrification reactor, and a stable average effluent pH of 7.7.

[0044] The present invention is a continuous flow hydrogen-based denitrification reactor composed of a hydrogen supply membrane component (hollow fiber membrane) and a micro multi-layer sponge. It treats low C / N nitrate-contaminated water, uses H2 as an electron donor and CO2 as an inorganic carbon source, stabilizes the pH of the reaction water, and removes nitrates efficiently and stably. The micro-sponge body serves as a retention space station for micro hydrogen bubbles in the water environment and an efficient working room for the reaction functional bacteria community. It absorbs and captures micro hydrogen that is not used in time in the water body, and promotes full contact between microorganisms and substrates. Compared with a hydrogen-based denitrification reactor equipped with only a hydrogen supply membrane component, the method of the present invention can improve the utilization efficiency of hydrogen electron donors, and has the advantages of stable operation, no secondary pollution, and high nitrate removal efficiency.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A system for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on biological sponges, characterized in that: include: A hydrogen-based denitrification reactor comprises a vertically placed reactor body (7), wherein hollow fiber membrane filaments (6) are placed in the reactor body (7), wherein the hollow fiber membrane filaments (6) are connected to membrane tubes (8), wherein the membrane tubes (8) are connected to H2 and CO2, and are used to introduce H2 and CO2 into the hollow fiber membrane filaments (6); the lower end of the reactor body (7) is connected to a raw water tank (1) via a water inlet pipe (3), a reflux pipe (4) is connected between one side of the upper end of the reactor body (7) and the water inlet pipe (3), and the other side of the upper end of the reactor body (7) is connected to a water outlet tank (2) via a water outlet pipe (12); A micro multilayer sponge (5) is inserted into the gaps inside and around the hollow fiber membrane filaments (6) to achieve tight wrapping of the membrane filaments. The micro multilayer sponge (5) is made of PPC modified hydrophilic polyurethane with a specific surface area of ​​>4500m 2 / m 3 The number of layers of the micro multi-layer sponge (5) filled in the reactor body (7) is not less than 10, and the filling volume is not less than 40% of the effective volume of the reactor body (7); the micro multi-layer sponge (5) is tightly arranged in the water environment around the hollow fiber membrane (6), and is stacked layer by layer to ensure that the micro hydrogen bubbles can enter a sufficient amount of micro multi-layer sponge to stay and be utilized during the diffusion process, avoid excessive squeezing and deformation between each other, and ensure that the sponge in a complete shape is conducive to the stay of the micro hydrogen bubbles and the efficient work and growth and reproduction of microorganisms.

2. The system for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on biological sponge according to claim 1, characterized in that: A water inlet pump is installed on the water inlet pipe (3), and a return pump is installed on the return pipe (4).

3. The system for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on biological sponge according to claim 2, characterized in that: The reflux flow rate of the reflux pipe (4) is 5-50 times the inlet flow rate of the water inlet pipe (3).

4. The system for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on biological sponge according to claim 1, characterized in that: The hollow fiber membrane (6) is made of PVDF, has an inner diameter of 1-3 mm, and an outer diameter of 1.5-6 mm.

5. The system for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on biological sponge according to claim 4, characterized in that: The hollow fiber membrane (6) is completely immersed in the suspended sludge in the reactor body (7), with a lateral extension length not exceeding 3 / 5 of the inner diameter of the reactor body (7), and a distance from the bottom of the reactor body (7) being 1 / 7-1 / 8 of the effective water depth. The rising flow rate of the water flow below the hollow fiber membrane (6) is controlled at 1-2 m / h.

6. The system for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on biological sponge according to claim 4, characterized in that: The size of a single sponge in the micro multi-layer sponge (5) is 1*1*1-5*5*5 cm.

7. The system for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on biological sponge according to claim 1, characterized in that: The membrane tube (8) is connected to the CO2 gas bag (9) and the H2 gas bag (10) through a three-way connection. The CO2 gas bag (9) and the H2 gas bag (10) are respectively connected to a gas extrusion water tank (11). The gas extrusion water tank (11) is used to supply water to the CO2 gas bag (9) and the H2 gas bag (10) to squeeze the gas into the hollow fiber membrane (6).

8. The system for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on biological sponge according to claim 1, characterized in that: The pH value in the reactor body (7) is 7.0-9.0, and the temperature is 20-35°C.

9. A method for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on biological sponges, characterized in that: The system for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on a biological sponge according to any one of claims 1 to 8 comprises the following steps: S1. Connect the lower end of the reactor body (7) to the water inlet pipe (3), which is connected to the raw water tank (1); connect one side of the upper end of the reactor body (7) to the reflux pipe (4), which is connected to the lower end of the reflux pipe (4); connect the other side of the upper end of the reactor body (7) to the water outlet pipe (12), which is connected to the water outlet tank (2); install hollow fiber membrane filaments (6) in the reactor body (7), and then inoculate sludge, and continue to fill the reactor body (7) with micro multilayer sponges (5), and insert the micro multilayer sponges (5) into the gaps inside and around the hollow fiber membrane filaments (6) to achieve tight wrapping of the membrane filaments, and connect the upper end of the hollow fiber membrane filaments (6) to H2 and CO2 through the membrane tube (8); S2. H2 and CO2 are provided to the hollow fiber membrane (6) and the reactor body (7), and the nitrate wastewater in the raw water tank (1) is continuously introduced into the hydrogen-based denitrification reactor. At the same time, the raw water in the reactor is refluxed through the reflux pipe (4). The micro multi-layer sponge (5) tightly wraps the hollow fiber membrane (6) to promote the removal of nitrate in the nitrate wastewater.

10. The method for enhancing the denitrification performance of a hydrogen-based denitrification reactor based on biological sponge according to claim 9, characterized in that: The MLVSS of the inoculated sludge is 3-8 g / L, the concentration of nitrate in the nitrate wastewater is 5-30 mg N / L, the H2 and CO2 feed contents per unit volume of the reactor are 150-800 mL / d, respectively, and the H2:CO2 ratio is 1:1-3:

1. The reaction time of the reactor is 8-15 h, the reflux flow rate of the reactor is 5-50 times the inlet flow rate, the pH value of the reactor is 7.0-9.0, and the temperature is 20-35°C.

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