A solar water electrolysis and anaerobic-aerobic combined biological water treatment system

Abstract

The invention discloses a solar water electrolysis and anaerobic-aerobic combined biological water treatment system, relating to the technical field of biological water treatment. The key points of the technical solution are as follows: a solar water electrolysis system comprising a solar cell group, an intelligent control unit, a water electrolysis cell, a cathode gas tank and an anode gas tank, the cathode gas tank and the anode gas tank being respectively connected to the water electrolysis cell, and the intelligent control unit controlling the operation of the solar water electrolysis system; a biological water treatment system comprising a biological reaction tank, a breathable membrane group, a sedimentation tank and a connecting pipe, the breathable membrane group being arranged in the biological reaction tank, the breathable membrane group comprising a hydrogen permeable membrane group and an oxygen permeable membrane group, the sedimentation tank being connected to the biological reaction tank, the hydrogen permeable membrane group being connected to the cathode gas tank, and the oxygen permeable membrane group being connected to the anode gas tank; the invention combines solar water electrolysis with a bioaffinity breathable membrane to directly provide electron donors and electron acceptors for biological water treatment, thereby improving the utilization rate of solar energy.

Description

Technical Field

[0001] The present invention relates to the field of biological water treatment, and more particularly to a solar water electrolysis and anaerobic-aerobic combined biological water treatment system. Background Art

[0002] Solar energy resources are abundant, do not require transportation, are environmentally friendly, and do not cause any pollution. However, the utilization of the sun is still in its early stages, and currently there are problems of high cost and low conversion rate. Therefore, the development of technology for the efficient and effective utilization of solar energy is of great significance.

[0003] The Chinese patent application publication number CN108069511A, which can be referenced, discloses a solar anaerobic reactor device for use in a treatment unit and its use method. The device includes an inlet main pipe, an outlet main pipe, an internal return pipe, a pump, a battery, a photoelectric controller, an inverter, and a generator. The device is primarily used to convert solar energy into electrical energy and store it in a solar battery. The photoelectric controller then converts the energy into a DC electrical signal. The DC signal can be directly used in DC appliances or it can be converted into an AC load by an inverter to supply AC appliances. The generator control system then provides electrical energy to an electric heating assembly below the solar photovoltaic assembly. The electric heating assembly converts the electrical energy into heat energy, providing a suitable temperature for the microorganisms in the anaerobic reactor and performing stable anaerobic purification of the water. At the same time, the generator control system provides electrical energy to the pump to achieve self-circulation and a stable state during normal operation of the device. Although the solar energy in this patented method is also used in a biological water treatment system, the solar energy is only used for heating and power supply.

[0004] The existing technology does not yet have a technical solution for directly applying the hydrogen and oxygen generated by solar water electrolysis as electron acceptors and electron donors in anaerobic and aerobic water treatment technologies, respectively. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a solar electrolysis water and anaerobic aerobic combined biological water treatment system, which combines solar electrolysis water with a bio-affinity breathable membrane to directly provide electron donors and electron acceptors for biological water treatment, thereby improving the utilization rate of solar energy, enhancing the denitrification effect, and reducing the addition of external carbon sources.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a solar water electrolysis and anaerobic and aerobic combined biological water treatment system, comprising:

[0007] A solar water electrolysis system comprising a solar cell group, an intelligent control unit, a water electrolysis cell, a cathode gas tank and an anode gas tank, wherein the cathode gas tank and the anode gas tank are respectively connected to the water electrolysis cell, and the intelligent control unit controls the operation of the solar water electrolysis system;

[0008] A biological water treatment system includes a biological reaction tank, a breathable membrane group, a sedimentation tank and a connecting pipe. The breathable membrane group is arranged in the biological reaction tank. The breathable membrane group includes a hydrogen permeable membrane group and an oxygen permeable membrane group. The sedimentation tank is connected to the biological reaction tank, the hydrogen permeable membrane group is connected to the cathode gas tank, and the oxygen permeable membrane group is connected to the anode gas tank.

[0009] By adopting the above technical solution, solar energy is directly applied to the water electrolysis cell to provide electron donors and electron acceptors, which are stored in the cathode gas tank and the anode gas tank respectively, and directly supplied to the hydrogen permeable membrane group and the oxygen permeable membrane group respectively, so that the growth conditions of aerobic and anaerobic microorganisms are met, the utilization rate of solar energy is improved, and the concentration of microorganisms on the surface of the hydrogen permeable membrane group and the oxygen permeable membrane group is increased.

[0010] Furthermore, the hydrogen permeable membrane group is connected to the cathode gas tank through a first delivery pipe, and the oxygen permeable membrane group is connected to the anode gas tank through a second delivery pipe. A first pressure gauge is provided on the first delivery pipe, and a second pressure gauge is provided on the second delivery pipe. The first pressure gauge and the second pressure gauge are both wirelessly connected to the intelligent control unit.

[0011] By adopting the above technical solution, the pressure in the pipe can be monitored and fed back through the first pressure gauge and the second pressure gauge, so that the intelligent control unit controls the operation of the solar cell group and the water electrolysis cell according to the pressure value.

[0012] Furthermore, the minimum working pressure of the first delivery pipe and the second delivery pipe is set to 10KPa, the maximum working pressure of the first delivery pipe and the second delivery pipe is set to 0.8MPa, the pressures measured by the first pressure gauge and the second pressure gauge are recorded as P1 and P2 respectively, when P1 and P2 are both less than 10Kpa, the intelligent control unit controls the solar cell group and the hydrolysis electrolytic cell to operate, and when P1 and P2 are both greater than 10Kpa, the intelligent control unit controls the solar cell group and the hydrolysis electrolytic cell to stop operating.

[0013] By adopting the above technical solution, the differential control of the aerobic zone and the anaerobic zone can be achieved by detecting the pressure in the tube, thereby promoting the reaction process in the biological reaction tank.

[0014] Furthermore, the biological reaction tank includes one or more of a hydrogen-type autotrophic biological reaction tank, an aerobic biological reaction tank, and an anaerobic-aerobic combined biological reaction tank.

[0015] By adopting the above technical solution, the present invention can place different types of microorganisms in the same bioreactor, quickly consume the intermediate products in the bioreactor, and improve mass transfer efficiency.

[0016] Furthermore, the breathable membrane group is composed of more than one breathable plate, the breathable plate is composed of a breathable membrane and functional fibers, and the breathable membrane is fixedly connected to the functional fibers.

[0017] By adopting the above technical solution, the functional fibers increase the convex range of the breathable membrane, so that the surface of the breathable membrane has a villi-like structure, which is conducive to the attachment and growth of microorganisms.

[0018] Furthermore, the breathable membrane is a polyvinylidene fluoride breathable membrane or a polytetrafluoroethylene breathable membrane, and the pore size of the breathable membrane is 0.1-1.0 μm.

[0019] Furthermore, the breathable membrane is a polydimethylsiloxane breathable membrane, and the thickness of the breathable membrane is 100-500 μm.

[0020] Furthermore, the length of the functional fiber is 0.1-5 mm.

[0021] Furthermore, the preparation method of the functional fiber is as follows:

[0022] The polymer material and the metal oxide are weighed in a proportion with a mass ratio of (80-90):(10-20), mixed and granulated using a twin-screw extruder, and then formed into long fibers using a wire drawing machine, and cut into predetermined lengths to obtain the product.

[0023] Furthermore, the polymer material is one or more of polyester, polyvinyl alcohol, polyamide, polyacrylonitrile, polypropylene and polyvinyl chloride; the metal oxide is one or more of ferroferric oxide, ferrous oxide, manganese dioxide, cobalt oxide and nickel oxide.

[0024] Furthermore, the preparation method of the breathable plate is as follows:

[0025] The method comprises the following steps: pouring a substrate solution that has been allowed to stand on a support and scraping it into a thin film with a thickness of 50-500 μm, wherein the substrate solution includes a substrate and a solvent, wherein the substrate is one of polyvinylidene fluoride, polytetrafluoroethylene, and polydimethylsiloxane, and the solvent is N,N-dimethylacetamide; equipping a hopper of an electrostatic flocking instrument with functional fibers, connecting the electrodes of the electrostatic flocking instrument to a support, and performing electrostatic flocking. After the solvent evaporates and the surface of the film dries, the film is immersed in a coagulation liquid to replace the solvent, thereby forming a breathable film with flocked surface.

[0026] In summary, the present invention has the following beneficial effects:

[0027] Unlike conventional methods of storing solar energy in batteries or directly utilizing solar energy for heating or power generation, the present invention uses an intelligent control unit to act on a water electrolysis cell, thereby providing electron donors and electron acceptors, thus expanding the application scope of solar energy. Furthermore, aerobic and anaerobic zones can be located separately or together in the same bioreactor, and the pressure value is used to control the aerobic and anaerobic zones, thereby rapidly consuming intermediate products, improving mass transfer efficiency, and enhancing pollutant removal rates.

[0028] The present invention adopts a flocked breathable membrane so that its surface has a villi structure, which is conducive to the attachment and growth of microorganisms, shortens the biofilm formation period on the breathable membrane surface from more than 20 days to less than 3 days, shortens the biofilm formation time, further increases the microbial activity and gas utilization rate on the breathable membrane surface, protects the biofilm from falling off, improves the denitrification effect, reduces the addition of external carbon sources, and improves the biological water treatment efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a control relationship diagram of the intelligent control unit of the present invention, the solar cell group and the water electrolysis cell;

[0030] Figure 2 Schematic diagram of the connection relationship between the solar water electrolysis system and the anaerobic and aerobic combined biological water treatment system of Example 1;

[0031] Figure 3 Schematic diagram of the connection relationship between the solar water electrolysis system and the anaerobic and aerobic combined biological water treatment system of Example 2;

[0032] Figure 4 It is a graph showing the removal efficiency of ammonia nitrogen, TN and COD for each embodiment and comparative example.

[0033] Among them, 1. Solar cell group; 2. Intelligent control unit; 3. Water electrolysis cell; 4. Anode gas tank; 5. Cathode gas tank; 6. Biological reaction tank; 7. Sedimentation tank; 8. Hydrogen permeable membrane group; 9. Oxygen permeable membrane group; 10. First delivery pipe; 11. First pressure gauge; 12. Second delivery pipe; 13. Second pressure gauge. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to the preparation examples and examples.

[0035] Preparation Example 1 of Functional Fiber

[0036] 9g of polyamide, 0.6g of ferric oxide, 0.2g of cobalt dioxide and 0.2g of nickel oxide were weighed, mixed and granulated using a twin-screw extruder, and then formed into long fibers using a wire drawing machine, and cut into functional fibers of a certain length.

[0037] Preparation Example 2 of Functional Fiber

[0038] 8g of polyester, 1.8g of ferrosoferric oxide and 0.2g of manganese dioxide were weighed, mixed and granulated using a twin-screw extruder, and then formed into long fibers using a drawing machine, and cut into functional fibers of a certain length.

[0039] It should be noted that the polymer materials for preparing the above-mentioned functional fibers include but are not limited to one or more of polyester, polyvinyl alcohol, polyamide, polyacrylonitrile, polypropylene and polyvinyl chloride; the metal oxides include but are not limited to one or more of ferroferric oxide, ferric oxide, manganese dioxide, cobalt oxide and nickel oxide.

[0040] Preparation Example 1 of Breathable Plate

[0041] Pour a 40% PTFE N,N-dimethylacetamide solution that has been allowed to stand on a support and scrape it into a film with a thickness of 300μm and a size of 10cm×10cm. Equip the hopper of the electrostatic flocking instrument with a functional fiber of 2mm in length, connect the electrodes of the electrostatic flocking instrument to the support, and perform electrostatic flocking. After the solvent evaporates and the surface of the film is dry, immerse it in a 50% ethanol solution to replace the solvent, forming a breathable membrane with a flocked surface.

[0042] Preparation Example 2 of Breathable Plate

[0043] Pour a 30% PVDF N,N-dimethylacetamide solution that has been allowed to stand on a support and scrape it into a film with a thickness of 200μm and a size of 10cm×10cm. Equip the hopper of an electrostatic flocking instrument with a functional fiber with a length of 0.6mm. Connect the electrodes of the electrostatic flocking instrument to the support for electrostatic flocking. After the solvent evaporates and the surface of the film is dry, immerse it in a 50% ethanol solution to replace the solvent, forming a breathable membrane with flocked surface.

[0044] In the above-mentioned preparation example of the breathable plate, as a preference, the functional fibers can also be electrostatically flocked on the substrate, and then the substrate and the breathable membrane are fixed; preferably, the two are fixed by a clamp; more preferably, the clamp includes a matching rectangular frame and a rectangular frame net, and the rectangular frame is provided with multiple screw holes, and the rectangular frame net is also provided with screw holes at corresponding positions to connect the two, and the mesh number of the rectangular net is 3-8 meshes.

[0045] It should be noted that the above-mentioned breathable plates include hydrogen permeable plates and oxygen permeable plates.

[0046] Example 1

[0047] A solar water electrolysis and anaerobic-aerobic combined biological water treatment system is operated, which includes a solar water electrolysis system and a biological water treatment system; the solar water electrolysis system includes a solar cell group, an intelligent control unit, a water electrolysis cell, an anode gas tank, and a cathode gas tank; the biological water treatment system includes a biological reaction tank, a breathable membrane group, a sedimentation tank and a connecting pipe. In this embodiment, the biological reaction tank includes a hydrogen-type autotrophic biological reaction tank and an aerobic biological reaction tank, the breathable membrane group includes a hydrogen permeable membrane group and an oxygen permeable membrane group, the hydrogen permeable membrane group is connected to the cathode gas tank, and the oxygen permeable membrane group is connected to the anode gas tank; the hydrogen permeable membrane group is composed of 9 groups of hydrogen permeable plates, and the hydrogen permeable plates use the breathable plates of Preparation Example 1 of the breathable plates, and the oxygen permeable membrane group is composed of 9 groups of oxygen permeable plates, and the oxygen permeable plates use the breathable plates of Preparation Example 1 of the breathable plates; the hydrogen permeable membrane group and the cathode gas tank are connected through a first delivery pipe, and the first delivery pipe is connected to the cathode gas tank. A first pressure gauge is installed on the first delivery pipe. The oxygen permeable membrane assembly and the anode gas tank are connected via a second delivery pipe, which is also equipped with a second pressure gauge. Both the first and second pressure gauges are wirelessly connected to the intelligent control unit. The minimum operating pressure of the first and second delivery pipes is set to 10 kPa, and the maximum operating pressure of the first and second delivery pipes is set to 0.8 MPa. The pressures measured by the first and second pressure gauges are recorded as P1 and P2, respectively. When P1 and P2 are both less than 10 kPa, the intelligent control unit controls the operation of the solar cell array and the hydrolysis electrolytic cell. When P1 and P2 are both greater than 10 kPa, the intelligent control unit controls the operation of the solar cell array and the hydrolysis electrolytic cell. The hydrogen-type autotrophic biological reactor contains anaerobic sludge output from the sedimentation tank, while the aerobic biological reactor contains aerobic sludge output from the sedimentation tank. The system operates in a sequencing batch mode, treating low-carbon-nitrogen ratio wastewater with a hydraulic retention time of 12 hours. The wastewater replacement ratio is 75%, and simulated wastewater concentrate is added at the beginning of each cycle. The system's ammonia nitrogen concentration is 50 mg / L, and COD concentration is 50 mg / L. It runs continuously for 30 days, with samples taken every two days to test the removal effects of ammonia nitrogen, total nitrogen and COD; its biofilm formation cycle is 2 days.

[0048] Example 2

[0049] A solar water electrolysis and anaerobic-aerobic combined biological water treatment system is operated, which includes a solar water electrolysis system and a biological water treatment system; the solar water electrolysis system includes a solar cell group, an intelligent control unit, a water electrolysis cell, an anode gas tank, and a cathode gas tank; the biological water treatment system includes a biological reaction tank, a breathable membrane group, a sedimentation tank, and a connecting pipe. In this embodiment, the biological reaction tank is an anaerobic-aerobic combined biological reaction tank, the breathable membrane group includes a hydrogen permeable membrane group and an oxygen permeable membrane group, the hydrogen permeable membrane group is connected to the cathode gas tank, and the oxygen permeable membrane group is connected to the anode gas tank; the hydrogen permeable membrane group is composed of 9 groups of hydrogen permeable plates, and the hydrogen permeable plates use the breathable plates of Preparation Example 2 of the breathable plates; the oxygen permeable membrane group is composed of 9 groups of oxygen permeable plates, and the oxygen permeable plates use the breathable plates of Preparation Example 2 of the breathable plates; the hydrogen permeable membrane group and the cathode gas tank are connected by a first delivery pipe The first delivery pipe is connected to the anode gas tank via a second delivery pipe, which is also equipped with a second pressure gauge. Both the first and second pressure gauges are wirelessly connected to the intelligent control unit. The minimum operating pressure of the first and second delivery pipes is set to 10 kPa, and the maximum operating pressure of the first and second delivery pipes is set to 0.8 MPa. The pressures measured by the first and second pressure gauges are recorded as P1 and P2, respectively. When P1 and P2 are both less than 10 kPa, the intelligent control unit controls the operation of the solar cell array and the hydrolysis electrolysis cell. When P1 and P2 are both greater than 10 kPa, the intelligent control unit controls the operation of the solar cell array and the hydrolysis electrolysis cell. The anaerobic-aerobic combined biological reactor contains activated sludge output from the sedimentation tank. It operates in a sequencing batch mode, treating low-carbon-nitrogen ratio wastewater with a hydraulic retention time of 12 hours. The wastewater replacement ratio is 75%, and simulated wastewater concentrate is added at the beginning of each cycle. The system's ammonia nitrogen concentration is 50 mg / L, and COD concentration is 50 mg / L. It runs continuously for 30 days, with samples taken every two days to test the removal effects of ammonia nitrogen, total nitrogen and COD; its biofilm formation cycle is 2 days.

[0050] Comparative Example 1

[0051] A solar water electrolysis and anaerobic-aerobic combined biological water treatment system is operated, which includes a solar water electrolysis system and a biological water treatment system; the solar water electrolysis system includes a solar cell group, an intelligent control unit, a water electrolysis cell, an anode gas tank, and a cathode gas tank; the biological water treatment system includes a biological reaction tank, a breathable membrane group, a sedimentation tank, and a connecting pipe. In this embodiment, the biological reaction tank includes a hydrogen-type autotrophic biological reaction tank and an aerobic biological reaction tank, the breathable membrane group includes a hydrogen permeable membrane group and an oxygen permeable membrane group, the hydrogen permeable membrane group is connected to the cathode gas tank, and the oxygen permeable membrane group is connected to the anode gas tank; the hydrogen permeable membrane is composed of 9 groups of hydrogen permeable plates, the hydrogen permeable plates are 0.45 micron polyvinylidene fluoride breathable plates, the oxygen permeable membrane group is composed of 9 groups of oxygen permeable plates, the oxygen permeable plates are 0.45 micron polyvinylidene fluoride breathable plates; the hydrogen permeable membrane group and the cathode gas tank are connected through a first delivery pipe, A first pressure gauge is installed on the first delivery pipe. The oxygen permeable membrane assembly and the anode gas tank are connected via a second delivery pipe, which is also equipped with a second pressure gauge. Both the first and second pressure gauges are wirelessly connected to the intelligent control unit. The minimum operating pressure of the first and second delivery pipes is set to 10 kPa, and the maximum operating pressure of the first and second delivery pipes is set to 0.8 MPa. The pressures measured by the first and second pressure gauges are recorded as P1 and P2, respectively. When P1 and P2 are both less than 10 kPa, the intelligent control unit controls the operation of the solar cell array and the hydrolysis electrolytic cell. When P1 and P2 are both greater than 10 kPa, the intelligent control unit controls the operation of the solar cell array and the hydrolysis electrolytic cell. The hydrogen-type autotrophic biological reactor is filled with anaerobic sludge output from the sedimentation tank, while the aerobic biological reactor is filled with aerobic sludge output from the sedimentation tank. The system operates in a sequencing batch mode, treating low-carbon-nitrogen ratio wastewater with a hydraulic retention time of 12 hours. The wastewater replacement ratio is 75%, and simulated wastewater concentrate is added at the beginning of each cycle. The system's ammonia nitrogen concentration is 50 mg / L, and COD concentration is 50 mg / L. It runs continuously for 30 days, with samples taken every two days to test the removal effects of ammonia nitrogen, total nitrogen and COD; its biofilm formation cycle is 25 days.

[0052] like Figure 4 As shown, since the functional fibers on the surface of the breathable membrane in Examples 1-2 can collect activated sludge flocs in the sludge, the initial oxygen permeability is improved, and thus the ammonia nitrogen and total nitrogen removal rates can be better in the initial stage of the reactor operation. The ammonia nitrogen and total nitrogen removal rates of each embodiment are 30-40% higher than those of the comparative example; as the operating time of the reactor increases, the functional fibers on the surface of the breathable membrane provide a suitable environment for the growth and reproduction of microorganisms, which is beneficial to increase the concentration of microorganisms on the membrane surface and enhance the treatment efficiency of functional microorganisms. Therefore, in the middle and late stages of the reactor operation, the ammonia nitrogen and total nitrogen removal rates of the embodiments are 10%-20% higher than those of the comparative example.

[0053] This embodiment and the comparative example were operated under low carbon-nitrogen ratio conditions; therefore, the COD removal rates were both relatively high, with no significant difference.

[0054] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as such modifications are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A solar water electrolysis and anaerobic and aerobic combined biological water treatment system, characterized in that: include: A solar water electrolysis system comprising a solar cell group, an intelligent control unit, a water electrolysis cell, a cathode gas tank and an anode gas tank, wherein the cathode gas tank and the anode gas tank are respectively connected to the water electrolysis cell, and the intelligent control unit controls the operation of the solar water electrolysis system; A biological water treatment system, comprising a biological reaction tank, a breathable membrane group, a sedimentation tank and a connecting pipe, wherein the breathable membrane group is arranged in the biological reaction tank, the breathable membrane group includes a hydrogen permeable membrane group and an oxygen permeable membrane group, the sedimentation tank is connected to the biological reaction tank, the hydrogen permeable membrane group is connected to the cathode gas tank, and the oxygen permeable membrane group is connected to the anode gas tank; The hydrogen permeable membrane group is connected to the cathode gas tank via a first delivery pipe, and the oxygen permeable membrane group is connected to the anode gas tank via a second delivery pipe. A first pressure gauge is provided on the first delivery pipe, and a second pressure gauge is provided on the second delivery pipe. Both the first pressure gauge and the second pressure gauge are wirelessly connected to the intelligent control unit. The breathable membrane group is composed of one or more breathable panels, and the breathable panels are composed of breathable membranes and functional fibers, and the breathable membranes are fixedly connected to the functional fibers; The functional fiber is prepared as follows: a polymer material and a metal oxide are weighed in a ratio of (80-90): (10-20), mixed and granulated using a twin-screw extruder, and then formed into long fibers using a wire drawing machine, which are then cut into predetermined lengths.

2. The biological water treatment system according to claim 1, characterized in that: The minimum working pressure of the first delivery pipe and the second delivery pipe is set to 10KPa, the maximum working pressure of the first delivery pipe and the second delivery pipe is set to 0.8MPa, the pressures measured by the first pressure gauge and the second pressure gauge are recorded as P1 and P2 respectively, when P1 and P2 are both less than 10Kpa, the intelligent control unit controls the solar cell group and the hydrolysis electrolytic cell to operate, and when P1 and P2 are both greater than 10Kpa, the intelligent control unit controls the solar cell group and the hydrolysis electrolytic cell to stop operating.

3. The biological water treatment system according to any one of claims 1-2, characterized in that: The biological reaction tank includes one or more of a hydrogen-type autotrophic biological reaction tank, an aerobic biological reaction tank, and an anaerobic-aerobic combined biological reaction tank.

4. The biological water treatment system according to claim 1, characterized in that The breathable membrane is a polyvinylidene fluoride breathable membrane or a polytetrafluoroethylene breathable membrane, and its pore size is 0.1-1.0 μm; or the breathable membrane is a polydimethylsiloxane breathable membrane, and its thickness is 100-500 μm.

5. The biological water treatment system according to claim 1, characterized in that: The length of the functional fiber is 0.1-5 mm.

6. The biological water treatment system according to claim 1, characterized in that: The polymer material is one or more of polyester, polyvinyl alcohol, polyamide, polyacrylonitrile, polypropylene and polyvinyl chloride; the metal oxide is one or more of ferroferric oxide, ferrous oxide, manganese dioxide, cobalt oxide and nickel oxide.

7. The biological water treatment system according to claim 1, characterized in that: The preparation method of the breathable plate is as follows: Pour the substrate solution that has been allowed to stand on a support and scrape it into a thin film with a thickness of 50-500 μm, wherein the substrate solution comprises a substrate and a solvent, wherein the substrate is one of polyvinylidene fluoride, polytetrafluoroethylene, and polydimethylsiloxane, and the solvent is N,N-dimethylacetamide; Functional fibers are installed in the hopper of the electrostatic flocking instrument, and the electrodes of the electrostatic flocking instrument are connected to the support for electrostatic flocking. After the solvent evaporates and the film surface dries, it is immersed in the coagulation liquid to replace the solvent, forming a breathable film with flocked surface.

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