A wastewater advanced denitrification and dephosphorization system, method and application based on membrane aeration enhanced AOA process

Abstract

The application belongs to the technical field of sewage treatment, and discloses a sewage advanced denitrification and dephosphorization system, method and application based on membrane aeration enhanced AOA process. The system comprises a water inlet tank, a water inlet pump, an SBR reactor, an electromagnetic drainage ball valve, a water outlet tank, a DO tester, a DO sensor, an aeration pump, a rotor flowmeter, a pressure gauge, a magnetic stirrer, an oxygen-permeable membrane assembly, an air inlet pipe and an air outlet pipe. The membrane aeration mode is adopted to replace the traditional diffusion aeration mode of the AOA system, so that the oxygen and organic matter are transferred in opposite directions, the nitrifying bacteria, denitrifying polysaccharide bacteria and denitrifying phosphorus bacteria are promoted to be cooperatively enriched, and then the nitrification, endogenous denitrification and denitrification dephosphorization processes are synchronously coupled. The carbon source competition bottleneck between the denitrifying bacteria and the phosphorus-removing bacteria in the low carbon-nitrogen ratio sewage system can be effectively broken, the problems of low efficiency of synchronous denitrification and dephosphorization, large carbon source consumption and the like in the traditional process can be solved, and the application has the advantages of low operation cost, strong adaptability, strong impact load resistance and the like.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and in particular to a wastewater deep nitrogen and phosphorus removal system, method and application based on membrane aeration enhanced AOA process. Background Technology

[0002] Deep nitrogen and phosphorus removal from urban wastewater with low carbon-to-nitrogen ratios has always been a key technical challenge restricting the development of the wastewater treatment industry. The anaerobic / aerobic / anoxic (AOA) process is a novel biological treatment technology that achieves deep nitrogen removal from wastewater with low carbon by enhancing the internal carbon source denitrification process. It utilizes denitrifying polysaccharide bacteria (DGAOs) to rapidly take up carbon sources from raw water in the anaerobic stage and convert them into intracellular storage substances (such as polyhydroxyalkanoates, PHAs) for storage. Subsequently, in the post-anoxic stage, the internal carbon source is used as an electron donor to denitrify the nitrates produced in the aerobic stage, thereby achieving deep nitrogen removal.

[0003] However, there is a significant carbon source competition problem between DGAOs and traditional polyphosphate-accumulating bacteria (PAOs) in this process. PAOs also need to consume a large amount of organic carbon source during the "anaerobic phosphorus release-aerobic phosphorus uptake" metabolism, which leads to insufficient internal carbon source available for denitrification, thus restricting the simultaneous improvement of nitrogen and phosphorus removal efficiency.

[0004] Denitrifying phosphorus-accumulating bacteria (DPAOs), due to their "dual-use of carbon" metabolic characteristics, can simultaneously complete denitrification and phosphorus uptake under anoxic conditions by using nitrate as an electron acceptor, thereby reducing carbon source demand. They are considered an important functional bacterial group for achieving simultaneous nitrogen and phosphorus removal. However, in the AOA process based on traditional aeration conditions, the high dissolved oxygen (DO) concentration in the liquid phase during the aerobic stage is more conducive to the accumulation of PAOs, making it difficult for DPAOs to become the dominant bacterial group. At the same time, there is a certain contradiction in controlling the aeration intensity during the aerobic stage: excessive aeration accelerates the oxidation and consumption of internal carbon sources, while insufficient aeration easily leads to incomplete ammonia nitrification, increasing the risk of excessive ammonia nitrogen in the effluent. Therefore, regulating the internal microenvironment of the reactor to promote the targeted accumulation of DPAOs and DGAOs and weaken the metabolic advantage of PAOs is of great significance for enhancing the performance of the AOA process in achieving simultaneous nitrogen and phosphorus removal in low-carbon wastewater.

[0005] Membrane-aerated biofilm reactors (MABRs) are based on oxygen-permeable membrane oxygen supply technology. They not only boast high oxygen transfer efficiency (saving over 50% more energy than traditional aeration) but also create an "aerobic-anoxic" radial dissolved oxygen (DO) gradient on the membrane surface: the biofilm on the membrane surface provides an aerobic environment (DO ≥ 2 mg / L), suitable for the colonization of nitrifying bacteria (such as Nitrosomonas and Nitrobacter); the liquid phase provides a hypoxic / anoxic environment (DO ≤ 0.2 mg / L), offering specific metabolic conditions for DGAOs and DPAOs. This spatial differentiation naturally limits the growth of PAOs that depend on aerobic environments, creating a niche advantage for DPAO enrichment.

[0006] Chinese patent publication CN116119838A discloses a method for enhancing pyridine degradation and simultaneous short-range denitrification in conjunction with a MABR process using functional bacteria. This method relies on the artificial addition of two specific functional bacterial strains (Rhizobium NJUST18 and Paracoccus denitrifyingis NJUST53) and employs a complex multi-stage inoculation process for biofilm formation. This increases the complexity of the process and operating costs, and the long-term stability of the exogenous bacteria in complex water quality environments is questionable.

[0007] Chinese patent publication CN121591344A discloses a wastewater treatment system and method suitable for high-altitude, low-pressure environments. It employs a two-stage SBR series process (first SBR for anaerobic phosphorus removal, second SBR-MABR for nitrogen removal). This results in a complex system structure, large footprint, and cumbersome operation and control. Furthermore, it primarily addresses the problems of low oxygen mass transfer efficiency and high energy consumption under high-altitude, low-pressure, low-oxygen, and low-temperature environments. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a wastewater deep nitrogen and phosphorus removal system, method and application based on membrane aeration enhanced AOA process.

[0009] The technical solution adopted by this invention to solve its technical problem is: A wastewater deep nitrogen and phosphorus removal system based on membrane aeration enhanced AOA (Aeration-Enhanced Aeration) technology includes an inlet tank, an inlet pump, a reactor, an electromagnetic drain ball valve, an outlet tank, a DO (dissolved oxygen) meter, a DO sensor, an aeration pump, a rotor flow meter, a pressure gauge, a magnetic stirrer, an oxygen-permeable membrane assembly, an air inlet pipe, an air outlet pipe, an inlet water pipe, and an outlet water pipe. The inlet tank and the reactor are connected via the inlet pump and the inlet water pipe. The inlet tank stores wastewater to be treated, and the reactor treats the wastewater inside. The inlet pump pumps water from the inlet tank into the reactor. The outlet tank and the reactor are connected via the electromagnetic drain ball valve and the outlet water pipe. The electromagnetic drain ball valve discharges the treated water from the reactor into the outlet tank. The oxygen-permeable membrane module is coaxially installed in the middle of the reactor. The oxygen-permeable membrane module can release oxygen into the reactor and perform membrane aeration. The top of the oxygen-permeable membrane module is connected to the aeration pump through the air inlet pipe. A rotor flow meter and a pressure gauge are connected in sequence along the direction from the aeration pump to the oxygen-permeable membrane module on the air inlet pipe. The aeration pump can input oxygen into the oxygen-permeable membrane module through the air inlet pipe. The rotor flow meter and pressure gauge are used to monitor the oxygen parameters in the air inlet pipe. The bottom of the oxygen-permeable membrane module is connected to the outside through the air outlet pipe. The air outlet pipe can discharge excess oxygen in the oxygen-permeable membrane module. The DO sensor is connected to the DO analyzer. The DO sensor is installed in the upper part of the reactor, and the DO analyzer is installed outside the reactor. The DO sensor can detect the dissolved oxygen content in the reactor and display it through the DO analyzer. The magnetic stirrer is coaxially installed at the bottom of the reactor and is also coaxially spaced below the oxygen-permeable membrane assembly. The magnetic stirrer can stir the wastewater inside the reactor.

[0010] Furthermore, the inlet pipe is a corrosion-resistant silicone pipe, and sealing gaskets are installed at the connection points with the inlet tank, inlet pump and reactor, and it is fixed with clamps. The inlet pump is connected to the bottom of the reactor through the inlet pipe and is spaced below the oxygen-permeable membrane assembly.

[0011] Furthermore, both the air inlet pipe and the air outlet pipe are made of aeration silicone tubing, and the connection points of the air inlet pipe to the reactor, aeration pump, rotor flow meter and pressure gauge are fixed with clamps.

[0012] Furthermore, the outlet pipe is a corrosion-resistant PVC pipe, and sealing gaskets are installed at the connection points with the outlet tank and the reactor, and it is fixed with clamps.

[0013] Furthermore, the DO sensor is fixedly connected and installed inside the reactor. The probe of the DO sensor can be completely inserted into the wastewater and is spaced apart from the oxygen permeable membrane assembly. The oxygen permeable membrane assembly is a dense, non-porous oxygen permeable membrane assembly.

[0014] Furthermore, the oxygen-permeable membrane module is more specifically a dense, non-porous hollow fiber oxygen-permeable membrane module; the vertical distance between the bottom of the oxygen-permeable membrane module and the bottom of the SBR reactor is 10~12 cm.

[0015] The installation method of the magnetic stirrer in the wastewater deep nitrogen and phosphorus removal system based on membrane aeration enhanced AOA process, as described above, includes the following steps: The magnetic stirrer is coaxially connected and positioned at the center of the bottom of the SBR reactor. This ensures that the stirring flow field uniformly covers the entire reactor area and avoids the formation of localized dead zones. Subsequently, the placement of the magnetic stirrer is fine-tuned, and the rotation status of the magnetic stirrer is checked through a no-load test run to ensure that there is no jamming, deviation, or collision with the reactor inner wall or membrane components during high-speed rotation, and that the rotation is smooth and the power output is stable.

[0016] The nitrogen and phosphorus removal method for a wastewater deep nitrogen and phosphorus removal system based on membrane aeration enhanced AOA process, as described above, is characterized by the following steps: (1) Activated sludge inoculation: Inoculate the reactor with activated sludge, and control the sludge concentration in the reactor to 5000~5500 mg / L after inoculation; (2) Water intake: Wastewater is pumped into the reactor from the water intake tank by the water intake pump; (3) Anaerobic stage: After the water is fed in or at the same time as the water is fed in, start the magnetic stirrer in the reactor to stir, so that the reactor is in an anaerobic state and the suspended sludge is completely mixed. Stir for 100~120 min. (4) Aerobic stage: Turn on the aeration pump to supply oxygen to the reactor through the oxygen permeable membrane assembly, control the aeration rate by adjusting the rotor flow meter, and control the pressure gauge reading to 5~20 kPa; monitor the dissolved oxygen concentration in the reaction process in real time through the DO sensor connected to the DO meter, and control the DO in the reactor to ≤0.2 mg / L; adjust the aeration time to 240~480 min according to the ammonia nitrogen removal.

[0017] (5) Anoxic stage: After aeration, turn off the aeration pump and keep the magnetic stirrer running to make the reactor enter the anoxic stirring stage. The running time is 120~300 min. (6) Sedimentation stage: Turn off the magnetic stirrer, and allow the reactor to settle to achieve mud-water separation; (7) Drainage stage: Open the electromagnetic drain ball valve to drain the supernatant into the outlet tank, thus completing one operating cycle.

[0018] Furthermore, the activated sludge originates from the secondary biological treatment tank of an urban wastewater treatment plant, and the wastewater is domestic sewage.

[0019] The above-mentioned deep nitrogen and phosphorus removal system for wastewater based on membrane aeration enhanced AOA process is applied to the treatment of high ammonia nitrogen industrial wastewater.

[0020] The advantages and positive effects of this invention are as follows: 1. This invention replaces the traditional diffusion aeration mode of the AOA system with membrane aeration, thereby achieving heterogeneous mass transfer between oxygen and organic matter, promoting the synergistic enrichment of nitrifying bacteria, denitrifying polysaccharide bacteria and denitrifying phosphorus-accumulating bacteria, and thus driving the synchronous coupling of nitrification, endogenous denitrification and denitrification phosphorus removal processes.

[0021] 2. This invention can effectively overcome the bottleneck of carbon source competition between denitrifying bacteria and phosphorus-removing bacteria in low carbon-to-nitrogen ratio wastewater systems, and solve the problems of low efficiency and high carbon source consumption in traditional processes for simultaneous denitrification and phosphorus removal. It has the advantages of low operating cost, strong adaptability, and strong resistance to shock loads, and can achieve deep treatment of nitrogen and phosphorus-containing wastewater with stable effluent quality. It is especially suitable for the treatment of low carbon-to-nitrogen ratio urban sewage and industrial wastewater.

[0022] 3. Based on the microenvironment gradient formed by membrane aeration, this invention can create an aerobic zone suitable for the growth of nitrifying bacteria on the membrane surface, while maintaining a low-oxygen or hypoxic environment in areas far from the membrane surface. This inhibits the excessive accumulation of PAOs that depend on a high dissolved oxygen environment, promotes the synergistic growth and metabolic synergy of DGAOs and DPAOs, reduces the oxidative consumption of intracellular carbon sources by oxygen, alleviates the carbon source competition problem in the treatment of low carbon-to-nitrogen ratio wastewater, and achieves low-carbon biological denitrification of wastewater.

[0023] 4. Under membrane aeration and oxygen supply conditions, this invention creates an aerobic environment in the biofilm region, while maintaining a low-oxygen or anoxic environment in the reactor liquid phase. This allows nitrification to primarily occur in the biofilm region, while denitrification and denitrification phosphorus removal reactions can proceed simultaneously in the liquid phase, thus achieving synergistic occurrence of nitrification, denitrification, and phosphorus removal processes. This structure reduces the system's dependence on the post-anoxic stage, shortens the anoxic reaction time, and improves the overall treatment efficiency of the reactor. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structural connection of the system in this invention; Figure 2 The diagram shows the operational effect of the wastewater deep nitrogen and phosphorus removal system in Example 1 of this invention after 60 days of operation; where (a) shows the changes in influent ammonia nitrogen, effluent ammonia nitrogen and ammonia nitrogen removal efficiency, (b) shows the removal efficiency of influent TN, effluent TN and TN, (c) shows the removal efficiency of influent COD, effluent COD and COD, and (d) shows the removal efficiency of influent TP, effluent TP and TP. Figure 3 The diagram shows the operating effect of the system in Comparative Example 1 of this invention after 60 days of operation; where (a) represents the changes in influent ammonia nitrogen, effluent ammonia nitrogen and ammonia nitrogen removal efficiency, (b) represents the removal efficiency of influent TN, effluent TN and TN, (c) represents the removal efficiency of influent COD, effluent COD and COD, and (d) represents the removal efficiency of influent TP, effluent TP and TP. Detailed Implementation

[0025] The present invention will be further described below with reference to the embodiments. The following embodiments are descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0026] The various experimental operations involved in the specific embodiments are all conventional techniques in the field. For parts not specifically annotated in this document, those skilled in the art can refer to various commonly used reference books, scientific and technological documents or related instructions and manuals prior to the filing date of this invention to carry out the operations.

[0027] A wastewater deep nitrogen and phosphorus removal system based on membrane aeration enhanced AOA process, such as Figure 1 As shown, the system includes an inlet tank 1, an inlet pump 2, a reactor 3, an electromagnetic drain ball valve 4, an outlet tank 5, a DO meter 6, a DO sensor 7, an aeration pump 8, a rotor flow meter 9, a pressure gauge 10, a magnetic stirrer 11, an oxygen-permeable membrane assembly 12, an air inlet pipe 13, an air outlet pipe 14, an inlet water pipe 15, and an outlet water pipe 16. The inlet tank 1 and the reactor 3 are connected via the inlet pump 2 and the inlet water pipe 15. The inlet tank 1 can store wastewater to be treated, and the reactor 3 can treat the wastewater inside. The inlet pump 2 can pump water from the inlet tank 1 into the reactor 3. The outlet tank 5 and the reactor 3 are connected via the electromagnetic drain ball valve 4 and the outlet water pipe 16. The electromagnetic drain ball valve 4 can discharge the treated water from the reactor 3 into the outlet tank 5.

[0028] The oxygen permeable membrane module 12 is coaxially installed in the middle of the reactor 3. The oxygen permeable membrane module 12 can release oxygen into the reactor 3 and perform membrane aeration. The top of the oxygen permeable membrane module 12 is connected to the aeration pump 8 through the air inlet pipe 13. A rotor flow meter 9 and a pressure gauge 10 are connected in sequence along the direction from the aeration pump 8 to the oxygen permeable membrane module 12 on the air inlet pipe 13. The aeration pump 8 can input oxygen into the oxygen permeable membrane module 12 through the air inlet pipe 13. The rotor flow meter 9 and the pressure gauge 10 are used to monitor the oxygen parameters in the air inlet pipe 13, so as to facilitate the staff to indirectly monitor the working status of the oxygen permeable membrane module 12. The bottom of the oxygen permeable membrane module 12 is connected to the outside through the air outlet pipe 14. The air outlet pipe 14 can discharge excess oxygen in the oxygen permeable membrane module 12 to ensure the safe operation of the oxygen permeable membrane module 12.

[0029] The DO sensor 7 is connected to the DO analyzer 6. The DO sensor 7 is installed in the upper part of the reactor 3, and the DO analyzer 6 is installed outside the reactor 3. The DO sensor 7 can detect the dissolved oxygen content in the reactor 3 and display it through the DO analyzer 6, which makes it convenient for the staff to monitor the working status of the reactor 3.

[0030] The magnetic stirrer 11 is coaxially installed at the bottom of the reactor 3 and is coaxially spaced below the oxygen-permeable membrane assembly 12. The magnetic stirrer 11 can stir the wastewater inside the reactor 3 to ensure that the reactor is in an anaerobic state and that the suspended sludge is mixed.

[0031] This invention, based on the microenvironmental gradient formed by membrane aeration, creates an aerobic zone suitable for nitrifying bacteria growth on the membrane surface of the oxygen-permeable membrane module 12, while maintaining a low-oxygen or anoxic environment in areas far from the membrane surface. This inhibits the excessive accumulation of PAOs dependent on high dissolved oxygen environments and promotes the synergistic growth and metabolic synergy of DGAOs and DPAOs, reducing the oxidative consumption of intracellular carbon sources by oxygen, alleviating carbon source competition in low C / N ratio wastewater treatment, and achieving low-carbon biological denitrification of wastewater. This system introduces membrane aeration technology into the AOA reaction system, effectively decoupling the mass transfer direction of oxygen and organic matter, thereby optimizing the microenvironmental gradient inside the reactor, promoting synergistic metabolism of functional microbial communities, and improving the system's denitrification performance.

[0032] In this embodiment, the inlet pipe 15 is a corrosion-resistant silicone pipe, and sealing gaskets (not shown in the figure) are installed at the connection points with the inlet tank 1, the inlet pump 2 and the reactor 3, and fixed with clamps (not shown in the figure) to improve the airtightness; the inlet pump 2 is connected to the bottom of the reactor 3 through the inlet pipe 15, and is spaced below the oxygen permeable membrane assembly 12 to ensure that the low carbon-to-nitrogen ratio wastewater is accurately and stably delivered to the reactor 3, and to avoid the membrane assembly being impacted by the excessive flow rate.

[0033] In this embodiment, both the air inlet pipe 13 and the air outlet pipe 14 are made of aeration silicone tubing. The connection points between the air inlet pipe 13 and the reactor 3, the aeration pump 8, the rotor flow meter 9 and the pressure gauge 10 are all fixed with clamps (not shown in the figure) to ensure no aeration leakage and to guarantee the stability and uniformity of aeration within the membrane.

[0034] In this embodiment, the water outlet pipe 16 is a corrosion-resistant PVC pipe, and sealing gaskets (not shown in the figure) are installed at the connection points with the water outlet tank 5 and the reactor 3, and fixed with clamps (not shown in the figure) to improve the airtightness.

[0035] In this embodiment, the DO sensor 7 is fixedly connected and installed inside the reactor 3. The probe of the DO sensor 7 can be fully inserted into the wastewater (the probe is about 30-35 cm from the bottom of the reactor 3) and is spaced apart from the oxygen permeable membrane assembly 12. A sealing sleeve (not shown in the figure) is installed at the connection between the probe of the DO sensor 7 and the inner surface of the SBR reactor 3, and sealant (not shown in the figure) is applied to prevent wastewater leakage. The DO sensor 7 is connected to the DO measuring instrument 6 through a signal transmission line (waterproof cable, not shown in the figure). The transmission line is tidied up and fixed to the outer wall of the reactor 3 to avoid wear and contact with the membrane assembly. The oxygen permeable membrane assembly 12 is a dense, non-porous oxygen permeable membrane assembly. The dense, non-porous oxygen-permeable membrane component is a component disclosed in the art. For example, Chinese Patent Publication CN214990550U discloses the packaging form, gas path interface design, and reactor installation and positioning scheme of such hollow fiber membrane aeration components; Chinese Patent Publication CN111482091A discloses the core structure, preparation process, and bubble-free aeration mass transfer principle of dense, non-porous hollow fiber composite membranes.

[0036] In this embodiment, the oxygen-permeable membrane module 12 is more specifically a dense, non-porous hollow fiber oxygen-permeable membrane module. The vertical distance between the bottom of the oxygen-permeable membrane module 12 and the bottom of the SBR reactor 3 is 10-12 cm. This distance ensures that the membrane module is located in the reaction zone of high-efficiency mass transfer within the reactor, allowing for full contact with the mixed liquid phase. During wastewater treatment, oxygen diffuses outward through the membrane wall from the inner cavity of the membrane fibers on the oxygen-permeable membrane module 12 in a bubble-free transport manner, and a biofilm spontaneously adheres and grows on the surface of the oxygen-permeable membrane. By adjusting the gas supply pressure, the dissolved oxygen (DO) in the SBR liquid phase can be maintained below 0.2 mg / L during membrane aeration. The membrane modules used include, but are not limited to, dense membranes and hollow fiber types; other membrane modules capable of oxygen permeability are also within the scope of protection of this patent.

[0037] In this embodiment, the installation method of the magnetic stirrer 11 includes the following steps: The magnetic stirrer 11 is coaxially connected and positioned at the center of the bottom of the SBR reactor 3. This ensures that the stirring flow field uniformly covers the entire reactor area, avoiding the formation of localized dead zones. The placement of the magnetic stirrer 11 is then fine-tuned, with adjustments not exceeding 50 mm. A no-load test run is conducted to check the rotation status of the magnetic stirrer, ensuring that there is no jamming, deviation, or collision with the reactor wall or membrane components during high-speed rotation, and that the rotation is smooth and the power output is stable. After the magnetic stirring system is operational, it can break the mass transfer boundary layer of the sludge-water mixture through forced turbulence, significantly enhancing the transfer efficiency between organic matter, dissolved oxygen, and activated sludge microorganisms within the reactor. Simultaneously, it prevents sludge from settling and compacting at the bottom of the reactor, providing a stable hydrodynamic environment for the biodegradation reaction within the SBR reactor.

[0038] The method of using the wastewater deep nitrogen and phosphorus removal system based on membrane aeration enhanced AOA process as described above includes the following steps: (1) Inoculation of activated sludge: Inoculate activated sludge into reactor 3. After inoculation, the sludge concentration in reactor 3 is controlled at 5000~5500 mg / L. (2) Water intake: Wastewater is pumped into reactor 3 from water intake tank 1 through water intake pump 2; (3) Anaerobic stage: After the water is fed in or at the same time as the water is fed in, start the magnetic stirrer 11 in the reactor 3 to stir, so that the reactor 3 is in an anaerobic state and the suspended sludge is completely mixed. The anaerobic stirring is carried out for 100~120 min. (4) Aerobic stage: Turn on the aeration pump 8 to supply oxygen to the reactor 3 through the oxygen permeable membrane component 12, control the aeration rate by adjusting the rotor flow meter 9, and control the pressure gauge 10 reading to 5~20 kPa; monitor the dissolved oxygen concentration in real time through the DO sensor 7 connected to the DO meter 6, and control the DO in the reactor 3 to ≤0.2 mg / L; adjust the aeration time to 240~480 min according to the effluent ammonia nitrogen concentration to ensure that the effluent ammonia nitrogen concentration is ≤5 mg / L.

[0039] (5) Anoxic stage: After aeration, turn off the aeration pump 8 and keep the magnetic stirrer 11 running to make the reactor enter the anoxic stirring stage. The running time is 120~300 min. (6) Sedimentation stage: Turn off magnetic stirrer 11 and let the reactor settle for 30~40 min to achieve mud-water separation; (7) Drainage stage: Open the electromagnetic drain ball valve 4 to drain the supernatant into the outlet tank 5, thus completing one operating cycle.

[0040] This invention, under membrane aeration and oxygen supply conditions, creates an aerobic environment in the biofilm region while maintaining a low-oxygen or anoxic environment in the reactor liquid phase. This allows nitrification to primarily occur in the biofilm region, while denitrification and denitrification phosphorus removal reactions can proceed simultaneously in the liquid phase, thus achieving synergistic occurrence of nitrification, denitrification, and phosphorus removal processes. This structure reduces the system's dependence on a post-anoxic stage, shortens the anoxic reaction time, and improves the overall treatment efficiency of the reactor.

[0041] In this embodiment, the activated sludge originates from the secondary biological treatment tank of an urban wastewater treatment plant, and the wastewater is domestic sewage.

[0042] Because this invention can perform deep nitrogen and phosphorus removal from wastewater, it is suitable for treating high-ammonia-nitrogen industrial wastewater, such as landfill leachate, sludge nitrification supernatant, aquaculture wastewater, and soybean product processing wastewater. Utilizing the high oxygen and mass transfer efficiency of membrane aeration and the layered structure of the biofilm, it achieves efficient nitrification and simultaneous denitrification, overcoming the problems of high oxygen demand and insufficient carbon source in traditional processes. Therefore, the deep nitrogen and phosphorus removal system described above is applicable to the treatment of high-ammonia-nitrogen industrial wastewater.

[0043] Specifically (the structural connections not described in detail are the same as those mentioned above) Figure 1 The system shown is "a wastewater deep nitrogen and phosphorus removal system based on membrane aeration enhanced AOA process" (shown in the image). Example 1: In the assembly stage of SBR reactor 3, the precise fixing and parameter adjustment of the oxygen permeable membrane module 12 are carried out first: the oxygen permeable membrane module 12 is stably installed using the existing dedicated membrane module frame. As the core support structure, the membrane module frame must be firmly snapped / fixed to the preset position in the middle of the SBR reactor 3 to ensure that the oxygen permeable membrane module 12 does not shift, shake, or tilt during the entire operation of SBR reactor 3. Subsequently, the vertical installation height of the membrane module unit is finely adjusted. Through methods such as scale calibration and fine adjustment of positioning bolts, the vertical distance between the bottom of the membrane module unit and the bottom of SBR reactor 3 is strictly controlled to be maintained in the range of 10~12 cm. This distance can ensure that the membrane module is in the reaction zone of efficient mass transfer in the reactor and fully contacts the mixed liquid phase. The oxygen permeable membrane module 12 selected in this project has a dense, non-porous structure, which is different from conventional porous membrane materials. This structure can prevent sludge particles and microbial cells from clogging the membrane channels, ensuring stable oxygen permeation efficiency. At the same time, during the installation process, it is necessary to avoid any scraping or collision between the oxygen permeable membrane module 12 and the inner wall of the SBR reactor 3. A reasonable safety gap of 60mm should be reserved to prevent damage to the membrane module body and failure of the sealing structure, and to ensure the structural integrity of the device.

[0044] System commissioning: Connect all equipment power and check the operating status of each component: Turn on the inlet pump 2, adjust the inlet flow rate to ensure stable flow without leakage and appropriate flow velocity; turn on the aeration pump 8, adjust the rotor flow meter 9, and observe the pressure gauge 10 value. The pressure gauge value needs to be adjusted according to the membrane pressure tolerance and aeration requirements of the membrane aerated biofilm reactor (MABR) to ensure stable aeration, no leakage, uniform aeration within the membrane, and DO maintained at less than or equal to 0.2 mg / L during the aerobic stage; turn on the magnetic stirrer 11. The speed needs to be adjusted according to the sludge concentration, carbon source distribution uniformity, and microbial mixing requirements within the reactor. If the sludge concentration is high (≥3000 mg / L), the speed can be adjusted to 250~300 r / min to ensure thorough mixing of sludge and wastewater and uniform substrate distribution; if the sludge concentration is low (<3000 mg / L), the speed can be adjusted to 200~250 r / min. To avoid excessive speed causing energy waste and biofilm detachment, ensure uniform mixing without jamming or noise, promote full contact between organic matter and biofilm, and prevent scouring of membrane components; open electromagnetic drain ball valve 4 to check for smooth water flow and no leakage; adjust DO sensor 7 to ensure accurate data monitoring and normal recording by DO meter 6; after adjustment, turn off the power to all equipment and wait for the system timer to start.

[0045] After the system equipment is connected and debugged, following the steps of the nitrogen and phosphorus removal reaction method described above, oxygen-permeable membrane module 12 is used for aeration. The dense, non-porous oxygen-permeable membrane module has stable oxygen transfer efficiency and low operating cost. It focuses on decoupling the direction of organic matter and oxygen transfer, promoting the synergistic enrichment of DGAOs and DPAOs, and breaking the bottleneck of carbon source competition in low carbon-to-nitrogen ratio wastewater. Time-series controlled operation is implemented, and the specific operation steps are as follows: 1) Activated sludge inoculation: Activated sludge is inoculated into SBR reactor 3. The activated sludge is derived from the secondary biological treatment tank of an urban wastewater treatment plant. After inoculation, the sludge concentration in SBR reactor 3 is controlled at 5000~5500 mg / L.

[0046] 2) Influent: Domestic sewage (COD=137.4-180.6 mg / L, ammonia nitrogen=40.5-62.3 mg / L, total nitrogen=42.1-63.5 mg / L, total phosphorus=4.4-10.6 mg / L, carbon-nitrogen ratio≈3:1) is pumped into SBR reactor 3 from influent tank 1 through influent pump 2.

[0047] 3) Anaerobic stage: After or during influent intake, start the magnetic stirrer 11 in SBR reactor 3 to stir the water, bringing the reactor into an anaerobic state. The suspended sludge is completely mixed. Anaerobic stirring lasts for 100-120 minutes. During this stage, DPAOs and DGAOs absorb small molecule organic matter such as volatile fatty acids (VFA) in the wastewater and convert them into intracellular storage carbon sources such as PHAs. 4) Aerobic Stage: Aeration pump 8 is turned on to supply oxygen to SBR reactor 3 through oxygen-permeable membrane module 12. The aeration rate is controlled at 100-150 mL / min by adjusting rotor flow meter 9, and the pressure gauge reading is controlled at 5-20 kPa. Dissolved oxygen concentration is monitored in real time by DO sensor 7 connected to DO meter 6, maintaining DO ≤ 0.2 mg / L in SBR reactor 3 to ensure an aerobic environment within the biofilm and an anoxic environment in the liquid phase. The aeration time is adjusted to 240-480 min based on ammonia nitrogen removal. During this stage, the oxygen-permeable membrane forms a stable dissolved oxygen gradient, and the biofilm exhibits significant spatial stratification: the inner layer of the membrane has a high dissolved oxygen concentration, where ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) are enriched and dominate the nitrification reaction, gradually oxidizing ammonia nitrogen to nitrate nitrogen; the outer layer of the biofilm and the suspended sludge phase have a low dissolved oxygen level, where DPAOs and DGAOs use the internal carbon source stored in the anaerobic section as electron donors to simultaneously carry out internal carbon source denitrification and phosphate over-absorption, achieving spatial coupling of nitrification, denitrification and biological phosphorus removal; 5) Anoxic Stage: After aeration, turn off aeration pump 8 and keep magnetic stirrer 11 running to bring the reactor into the anoxic stirring stage, which lasts for 120-300 minutes. During this stage, there is no aeration supply, the nitrification reaction stops completely, and the outer layer of biofilm and suspended sludge maintain a stable anoxic microenvironment. DPAOs and DGAOs continue to utilize the intracellular carbon source stored in their cells, using nitrate nitrogen as an electron acceptor, to further enhance the internal carbon source denitrification and denitrification phosphorus accumulation processes, completing the deep removal of residual nitrate nitrogen and phosphate, and ultimately achieving efficient and synergistic nitrogen and phosphorus removal in the system. 6) Sedimentation stage: Turn off magnetic stirrer 11 and allow the reactor to settle for 30-40 minutes to achieve mud-water separation; 7) Drainage stage: Open the electromagnetic drain ball valve 4 to drain the supernatant into the effluent tank 5, thus completing one operating cycle. Continuously operate for 60 days, recording monitoring data, effluent water quality data, functional bacteria activity, and functional bacteria abundance for each stage daily.

[0048] The construction and operation of the membrane aeration enhanced AOA process were studied, and the results after 60 days of operation were as follows: Figure 2 As shown: (a) the changes in influent ammonia nitrogen, effluent ammonia nitrogen, and ammonia nitrogen removal efficiency; (b) the removal efficiency of influent TN, effluent TN, and TN; (c) the removal efficiency of influent COD, effluent COD, and COD; (d) the removal efficiency of influent TP, effluent TP, and TP. Figure 2The average value over 60 days was taken, and the results are as follows: ammonia nitrogen removal rate = (91.25±0.7)%, total nitrogen removal rate = (85±0.6)%, total carbon removal rate = (94.0±1.0)%, and total phosphorus removal rate = (92.4±2.3)%. All of the above data meet the Class A standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002). It can be seen that the system has a high efficiency and stable removal capacity for ammonia nitrogen, total nitrogen, COD and total phosphorus. The enrichment of DGAOs and DPAOs in sludge has been significantly improved, breaking the bottleneck of carbon source competition in wastewater with low carbon-to-nitrogen ratio, driving the simultaneous coupling of nitrification, endogenous denitrification and denitrification phosphorus removal processes, and effectively solving the problems of low efficiency and large carbon source consumption of traditional processes for simultaneous nitrogen and phosphorus removal.

[0049] Comparative Example 1 This comparative example uses the same AOA process and component specifications as Example 1 (except for the removal of all membrane components and the replacement of the aeration method), with the aeration method replaced by traditional diffusion aeration. The remaining components, equipment connection methods, and operating parameters are completely identical (both are low C / N ratio wastewater and no additional carbon source is added). It is used to compare the differences between the system of this invention and the traditional aeration system in terms of nitrogen and phosphorus removal efficiency and operating costs, highlighting the advantages of this invention.

[0050] Specifically: 1. Compare the differences: (1) Adjustment of SBR reactor 3 and oxygen permeable membrane module 12: cancel equipment connection and all membrane module related structures in the denitrification and dephosphorization reaction (including oxygen permeable membrane module 12, inlet pipe 13, outlet pipe 14), and there are no membrane modules and membrane related installation structures; (2) Replacement of aeration method: The traditional diffusion aeration method (bottom aeration head aeration of SBR reactor 3) is adopted. The aeration pipe and aeration head are installed at the bottom of SBR reactor 3. The specifications and connection methods of aeration pump 8, rotor flow meter 9 and pressure gauge 10 are consistent. Aeration is carried out through bottom aeration head in the aerobic stage, which cannot achieve decoupling of the direction of transfer of organic matter and oxygen. (3) Other conditions: The component specifications (except membrane modules and reactor types), equipment connection methods, and operating parameters (influent is the same low carbon-to-nitrogen ratio wastewater, influent flow rate, sludge concentration, operating cycle, rotation speed at each stage, DO concentration, temperature, etc.) are completely consistent with those in Example 1. No additional carbon source is added to ensure the fairness of the comparison. The focus is on comparing the differences in nitrogen and phosphorus removal efficiency and operating costs.

[0051] 2. Operation process: Following the equipment connection and denitrification / phosphorus removal reaction operation method of Example 1, after adjusting the type of SBR reactor 3, removing the membrane module, and changing the aeration method, the equipment connection and commissioning were completed (no need to install the membrane module and related air inlet pipe 13 and air outlet pipe 14). The activated sludge inoculation (the same activated sludge as the secondary biological tank activated sludge of the denitrification / phosphorus removal reaction) and the operation of each stage were basically the same as in Example 1, except that the aerobic stage was carried out by traditional diffusion aeration through the bottom aeration head, and the aeration was turned off in the anaerobic and anoxic stages. The remaining operations were the same as the equipment connection and S2 denitrification / phosphorus removal reaction of Example 1. The system was run continuously for 60 days without adding any additional carbon source. The monitoring data, effluent water quality data, functional bacteria activity determination and functional bacteria abundance were recorded daily for each stage.

[0052] 3. Microbial metabolic processes at each stage in the comparative example: In this comparative example, due to the limitations of traditional diffusion oxygen supply methods, microbial metabolism was disordered at each stage, competition among microbial communities intensified, and the functions of DPAOs and DGAOs were significantly inhibited, ultimately resulting in poor nitrogen and phosphorus removal efficiency of the system. The specific microbial metabolic processes at each stage are as follows: Anaerobic stage: The core metabolic process in this stage is that DPAOs and DGAOs actively take up organic matter (mainly VFAs) in the wastewater and convert it into PHAs for storage as a carbon source for subsequent metabolism. Among them, DPAOs will simultaneously undergo intracellular polyphosphate (Poly-P) hydrolysis, decomposing Poly-P into inorganic phosphates and releasing them into the liquid phase, completing the anaerobic phosphorus release process. However, in this comparative case, there are two key problems that interfere with the normal metabolism of microorganisms: (1) the high concentration of nitrate nitrogen remaining from the previous operating cycle was not completely removed; (2) the high DO in the liquid phase during the aerobic stage promotes the proliferation of PAOs (which prefer an alternating anaerobic / aerobic metabolic environment). These two factors lead to traditional heterotrophic denitrifying bacteria, PAOs, and DPAOs and DGAOs competing for limited VFAs. Ultimately, this results in insufficient carbon source supply for DPAOs and DGAOs, a significant reduction in PHA synthesis, and inhibition of the Poly-P hydrolysis and phosphorus release process of DPAOs.

[0053] Aerobic stage: The core objective of this stage is to achieve efficient nitrification by nitrifying bacteria, converting ammonia nitrogen in wastewater into nitrate nitrogen, and providing electron acceptors for subsequent anoxic denitrification. However, the traditional diffusion aeration mode has obvious drawbacks. In order to ensure that the nitrification reaction proceeds fully, the liquid phase DO concentration needs to be controlled above 3 mg / L. A high DO concentration will cause two major adverse effects: (1) DO will induce premature oxidation and decomposition of PHAs stored in DPAOs and DGAOs, resulting in ineffective loss of internal carbon sources and further reducing the carbon source reserves required for subsequent denitrification; (2) A sufficient DO environment will promote the enrichment of PAOs, causing PAOs to compete with DPAOs and DGAOs for carbon sources in the anaerobic stage, significantly inhibiting the phosphorus uptake activity of DPAOs and the basic metabolic function of DGAOs.

[0054] Anoxic stage: The core metabolism in this stage involves DPAOs and DGAOs using PHAs stored in the anaerobic stage as electron donors and nitrate nitrogen produced in the aerobic stage as electron acceptors to reduce nitrate nitrogen to nitrogen gas, thus achieving nitrogen removal. Simultaneously, DPAOs complete the excess phosphorus uptake process. However, due to the combined adverse effects of the first two stages, the denitrification reaction of DPAOs and DGAOs cannot proceed fully, resulting in poor nitrogen removal efficiency. Furthermore, the enriched PAOs undergo secondary phosphorus release under anoxic conditions, hydrolyzing intracellularly stored Poly-P and releasing it into the liquid phase, leading to unstable phosphorus removal and ultimately making it difficult for the overall system treatment effect to reach the ideal level.

[0055] 4. Results: The results of the 60-day operation of Comparative Example 1 are as follows: Figure 3 As shown: (a) the changes in influent ammonia nitrogen, effluent ammonia nitrogen, and ammonia nitrogen removal efficiency; (b) the removal efficiency of influent TN, effluent TN, and TN; (c) the removal efficiency of influent COD, effluent COD, and COD; (d) the removal efficiency of influent TP, effluent TP, and TP. Figure 3 The average value over 60 days was taken, and the results are as follows: ammonia nitrogen removal rate = (50.45±1.2)%, total nitrogen removal rate = (44.9±1.3)%, total carbon removal rate = (85±0.7)%, and total phosphorus removal rate = (64.4±1.9)%. During operation, traditional diffusion aeration cannot decouple the direction of organic matter and oxygen transfer. Oxygen consumes a large amount of intracellular carbon source, resulting in fierce competition for carbon source. The enrichment of DGAOs and DPAOs is low, and the nitrogen and phosphorus removal efficiency decreases significantly. The membrane-free module assists in the differentiation of bacterial spatial ecological niches. The metabolic environment of nitrifying bacteria, denitrifying bacteria, and DPAOs interferes with each other, further reducing the treatment efficiency.

[0056] 5. Comparative Analysis: Comparing the operational results of Example 1 and Comparative Example 1, it is evident that the system of Example 1 (membrane aeration enhanced AOA process, in-membrane aeration + dense non-porous membrane module) has significant advantages over the traditional diffusion aeration system (without membrane module) in the treatment of wastewater with a low carbon-to-nitrogen ratio. These advantages are specifically reflected in the following aspects, which fully correspond to the core points of the beneficial effects of this invention: (1) Comparison of denitrification effects: The ammonia nitrogen removal rate of the system in Example 1 (91.25±0.7)% was 40.8 percentage points higher than that of Comparative Example 1, and the total nitrogen removal rate (85±0.6)% was 40.1 percentage points higher than that of Comparative Example 1. The main reason is that by aeration inside the oxygen-permeable membrane and the construction of a microenvironment of "aerobic inside the membrane and hypoxic outside the membrane" by the membrane module, the spatial ecological niche of bacteria is optimized, DGAOs and DPAOs work together to significantly prolong the intracellular carbon source metabolism time, improve the denitrification efficiency, achieve simultaneous nitrification and denitrification, and avoid incomplete nitrification of ammonia nitrogen. In contrast, the traditional diffusion aeration system (without membrane) has uneven distribution of dissolved oxygen in the aerobic stage, making it impossible to accurately control the DO concentration. Local aerobic areas are prone to appear in the anaerobic and hypoxic stages, which inhibits the activity of denitrifying bacteria and DGAOs. Moreover, without the assistance of membrane modules to differentiate the ecological niche of bacteria, the nitrification and denitrification processes interfere with each other. In addition, the carbon source is insufficient, resulting in a significant reduction in denitrification efficiency.

[0057] (2) Comparison of carbon removal effect and carbon source competition resolution effect: The total carbon removal rate of the system of the present invention (94±1.0)% is 9 percentage points higher than that of Comparative Example 1 (85±0.7)%. Example 1 adopts the oxygen-permeable membrane aeration method, which realizes the effective decoupling of the direction of organic matter and oxygen transfer, optimizes the spatial ecological niche differentiation of multifunctional bacteria, reduces the consumption of intracellular carbon source by oxygen, and promotes the synergistic enrichment and functional performance of DGAOs and DPAOs. It makes full use of intracellular carbon source to complete nitrogen and phosphorus removal, breaks the carbon source competition bottleneck of low carbon-nitrogen ratio wastewater, and achieves efficient treatment without the need for additional carbon source addition. In contrast, the traditional diffusion aeration method (without membrane) couples the direction of organic matter and oxygen transfer, and oxygen consumes a large amount of intracellular carbon source. Moreover, the membrane-free component constructs a dedicated metabolic microenvironment, which makes it impossible for DGAOs and DPAOs to be effectively enriched. The carbon source competition is fierce, resulting in a decrease in nitrogen and phosphorus removal efficiency.

[0058] (3) Comparison of phosphorus removal effect: The total phosphorus removal rate of the system in Example 1 (92.4±2.3)% was 28 percentage points higher than that in Comparative Example 1. The main reason is that the aeration inside the MABR membrane can optimize the enrichment and function of DGAOs. DGAOs can simultaneously achieve deep phosphorus absorption during denitrification. At the same time, the uniformity of aeration inside the membrane can ensure that polyphosphate-accumulating bacteria can fully absorb phosphorus in the aerobic stage. The membrane module can also help improve the sludge-water separation effect and promote the sedimentation and removal of phosphorus. In contrast, the traditional diffusion aeration system (without membrane) has poor sludge-water mixing uniformity. Insufficient carbon source leads to limited metabolism of polyphosphate-accumulating bacteria and DGAOs, resulting in insufficient phosphorus absorption. Moreover, without the assistance of membrane module for sludge-water separation, some phosphorus-containing sludge is easily lost with the effluent, further reducing the phosphorus removal efficiency.

[0059] (4) Comparison of operating costs and stability: The system in Example 1 uses oxygen-permeable membrane aeration, which has high oxygen transfer efficiency and saves more than 50% energy compared with traditional diffusion aeration. Combined with the advantage of not needing to add an additional carbon source, it greatly saves the system operating costs. In contrast, Comparative Example 1 (no membrane + traditional aeration) has high aeration energy consumption and operating costs that are more than 50% higher than the present invention. Moreover, the membrane-free component helps stabilize sludge performance, resulting in poor operating stability.

[0060] (5) Comparison of bacterial enrichment and microenvironment: The system in Example 1 constructs a dedicated microenvironment through oxygen-permeable membrane components, realizing the spatial ecological niche differentiation of multifunctional bacteria. The enrichment of DGAOs and DPAOs in sludge is significantly increased, providing bacterial support for efficient nitrogen and phosphorus removal. In contrast, the traditional aeration system (without membrane) does not have a dedicated microenvironment differentiation. The metabolic environments of various functional bacteria interfere with each other, and DGAOs and DPAOs cannot be effectively enriched. The sludge activity is low, which further restricts the treatment efficiency.

[0061] In summary, a comparison between Example 1 and Comparative Example 1 shows that this invention enhances the AOA process through membrane aeration, using an oxygen-permeable membrane aeration method instead of traditional diffusion aeration, and selecting a dense, non-porous membrane module. This effectively decouples the direction of organic matter and oxygen transfer, optimizes the spatial niche differentiation of multifunctional bacteria, promotes the synergistic enrichment of DGAOs and DPAOs, breaks through the carbon source competition bottleneck in low C / N ratio wastewater, drives the synchronous coupling of nitrification, denitrification, and phosphorus removal processes, significantly extends the intracellular carbon source metabolism time, improves nitrogen removal efficiency, and simultaneously enhances system operational stability and reduces operating costs. Compared to traditional aeration systems (without oxygen-permeable membrane modules), the nitrogen and phosphorus removal efficiency and operational stability are significantly improved, and the operating costs are greatly reduced. This solves the core defects of traditional systems and highlights the significant advantages of this invention.

[0062] Although embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the scope of the invention is not limited to the contents disclosed in the embodiments.

Claims

1. A method for deep nitrogen and phosphorus removal in a wastewater system based on membrane aeration enhanced AOA (Automatic Aeration) technology, characterized in that: Includes the following steps: (1) Inoculation of activated sludge: Inoculate activated sludge into reactor (3), and control the sludge concentration in reactor (3) after inoculation to 5000~5500 mg / L; (2) Water intake: Wastewater is pumped from the water intake tank (1) into the reactor (3) through the water intake pump (2); (3) Anaerobic stage: After the water is fed in or at the same time as the water is fed in, start the magnetic stirrer (11) in the reactor (3) to stir, so that the reactor (3) is in an anaerobic state and the suspended sludge is completely mixed. Stir for 100~120 min; DPAOs and DGAOs absorb the volatile fatty acid VFA small molecule organic matter in the sewage and convert it into PHAs intracellular storage type internal carbon source. (4) Aerobic stage: Turn on the aeration pump (8) to supply oxygen to the reactor (3) through the oxygen permeable membrane assembly (12), control the aeration rate by adjusting the rotor flow meter (9), and control the pressure gauge (10) reading to 5~20 kPa; monitor the dissolved oxygen concentration in real time through the DO sensor (7) connected to the DO meter (6), and control the DO in the reactor (3) to be ≤0.2 mg / L; adjust the aeration time to 240~480 min according to the ammonia nitrogen removal situation; the dissolved oxygen concentration in the inner layer of the membrane is high, and the ammonia oxidizing bacteria AOB and nitrite oxidizing bacteria NOB are enriched and dominate the nitrification reaction, gradually oxidizing ammonia nitrogen to nitrate nitrogen; the dissolved oxygen level in the outer layer of the biofilm and the suspended sludge phase is low, and DPAOs and DGAOs use the internal carbon source stored in the anaerobic section as electron donors to simultaneously carry out internal carbon source denitrification and phosphate over-absorption; (5) Anoxic stage: After aeration, turn off the aeration pump (8) and keep the magnetic stirrer (11) running to make the reactor enter the anoxic stirring stage. The running time is 120~300 min. DPAOs and DGAOs continue to use the internal carbon source stored in the cell, and use nitrate nitrogen as electron acceptor to further enhance the internal carbon source denitrification and denitrification polyphosphate process, and complete the deep removal of residual nitrate nitrogen and phosphate. (6) Sedimentation stage: Turn off the magnetic stirrer (11), and the reactor settles to achieve mud-water separation; (7) Drainage stage: Open the electromagnetic drain ball valve (4) to drain the supernatant into the outlet tank (5), thus completing one operating cycle; The oxygen permeable membrane module (12) is a dense, non-porous hollow fiber oxygen permeable membrane module; the vertical distance between the bottom of the oxygen permeable membrane module (12) and the bottom of the SBR reactor (3) is 10~12 cm.

2. The nitrogen and phosphorus removal method according to claim 1, characterized in that: The system includes an inlet tank (1), an inlet pump (2), a reactor (3), an electromagnetic drain ball valve (4), an outlet tank (5), a DO meter (6), a DO sensor (7), an aeration pump (8), a rotor flow meter (9), a pressure gauge (10), a magnetic stirrer (11), an oxygen permeable membrane assembly (12), an air inlet pipe (13), an air outlet pipe (14), an inlet water pipe (15), and an outlet water pipe (16). The inlet tank (1) and the reactor (3) are connected by the inlet pump (2) and the inlet water pipe (15). The inlet tank (1) can store wastewater to be treated, and the reactor (3) can treat the wastewater inside. The inlet pump (2) can pump water from the inlet tank (1) into the reactor (3). The outlet tank (5) and the reactor (3) are connected by the electromagnetic drain ball valve (4) and the outlet water pipe (16). The electromagnetic drain ball valve (4) can discharge the treated water from the reactor (3) into the outlet tank (5). The oxygen permeable membrane module (12) is coaxially installed in the middle of the reactor (3). The oxygen permeable membrane module (12) can release oxygen into the reactor (3) and perform membrane aeration. The top of the oxygen permeable membrane module (12) is connected to the aeration pump (8) through the air inlet pipe (13). The rotor flow meter (9) and pressure gauge (10) are connected in sequence along the direction from the aeration pump (8) to the oxygen permeable membrane module (12) through the air inlet pipe (13). The aeration pump (8) can input oxygen into the oxygen permeable membrane module (12) through the air inlet pipe (13). The rotor flow meter (9) and pressure gauge (10) are used to monitor the oxygen parameters in the air inlet pipe (13). The bottom of the oxygen permeable membrane module (12) is connected to the outside through the air outlet pipe (14). The air outlet pipe (14) can discharge excess oxygen in the oxygen permeable membrane module (12). The DO sensor (7) is connected to the DO meter (6). The DO sensor (7) is installed in the upper part of the reactor (3), and the DO meter (6) is installed outside the reactor (3). The DO sensor (7) can detect the dissolved oxygen content in the reactor (3) and display it through the DO meter (6). The magnetic stirrer (11) is coaxially installed at the bottom of the reactor (3) and coaxially spaced below the oxygen permeable membrane assembly (12). The magnetic stirrer (11) can stir the sewage inside the reactor (3).

3. The nitrogen and phosphorus removal method according to claim 2, characterized in that: The inlet pipe (15) is a corrosion-resistant silicone pipe, and sealing gaskets are installed at the connection points with the inlet tank (1), the inlet pump (2) and the reactor (3), and fixed with clamps. The inlet pump (2) is connected to the bottom of the reactor (3) through the inlet pipe (15) and is spaced below the oxygen permeable membrane assembly (12).

4. The nitrogen and phosphorus removal method according to claim 2, characterized in that: Both the air inlet pipe (13) and the air outlet pipe (14) are made of aeration silicone tubing. The air inlet pipe (13) is fixed with clamps at the connection points with the reactor (3), aeration pump (8), rotor flow meter (9) and pressure gauge (10).

5. The nitrogen and phosphorus removal method according to claim 2, characterized in that: The outlet pipe (16) is a corrosion-resistant PVC pipe, and sealing gaskets are installed at the connection points with the outlet tank (5) and the reactor (3), and it is fixed with clamps.

6. The nitrogen and phosphorus removal method according to claim 2, characterized in that: The DO sensor (7) is fixedly connected and installed inside the reactor (3). The probe of the DO sensor (7) can be fully inserted into the wastewater and is spaced apart from the oxygen permeable membrane assembly (12).

7. The nitrogen and phosphorus removal method according to any one of claims 2 to 6, characterized in that: The activated sludge comes from the secondary biological treatment tank of an urban wastewater treatment plant, and the wastewater is domestic sewage.

8. The application of the denitrification and phosphorus removal method as described in any one of claims 1 to 7 in the treatment of high ammonia nitrogen industrial wastewater.

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