Efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation

Abstract

The invention provides an efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation, and relates to the field of autotrophic nitrogen removal. The efficient autotrophic nitrogen removal system based on anaerobic ammonia oxidation comprises a pretreatment module, an adjusting module, an anaerobic ammonia oxidation reaction module, an adjusting control module, a nitrogen element balance module and a water and gas discharging module which are connected in sequence, the pretreatment module is used for carrying out preliminary physical or chemical treatment on input nitrogen-containing wastewater, removing large particles, grease and suspended solids, controlling the turbidity of inlet water and ensuring the mass transfer efficiency of a subsequent biological reaction unit. According to the invention, trace greenhouse gases in the tail gas are monitored and treated through the gas treatment unit, so that the emission of the greenhouse gases is reduced, and nitrogen in wastewater can be efficiently recovered and released in a harmless nitrogen form, so that the generation of nitrogen pollution is reduced; the autotrophic nitrogen removal system and method have the characteristics of low energy consumption, low material consumption and low sludge yield.

Description

Technical Field

[0001] This invention relates to the field of autotrophic denitrification, specifically to a highly efficient autotrophic denitrification system and method based on anaerobic ammonia oxidation. Background Technology

[0002] Autotrophic denitrification is a process in which autotrophic microorganisms use simple inorganic substances such as bicarbonate, ammonia, and formic acid as the main electron donors or acceptors to reduce nitrates to harmless gases such as nitrogen or nitrite. Unlike heterotrophic denitrification, autotrophic denitrification does not require organic matter as a carbon source, but relies on inorganic carbon sources such as carbonates or nitrogen compounds to obtain energy and biocarbon.

[0003] However, in traditional autotrophic denitrification systems, the two processes of short-cut nitrification and anaerobic ammonia oxidation are often spatially separated (e.g., two independent reactors) or alternately carried out in time, resulting in a long process flow, complex control, unstable hydraulic and substrate connection between the two units, and difficulty in maintaining the optimal ratio of ammonia nitrogen to nitrite nitrogen. This leads to large fluctuations in process efficiency, and the anaerobic ammonia oxidation reaction is often inhibited due to insufficient substrate (nitrite) supply or imbalance in ratio, making it difficult for the overall denitrification efficiency to reach the theoretical maximum value.

[0004] Therefore, those skilled in the art have provided a highly efficient autotrophic denitrification system and method based on anaerobic ammonia oxidation to solve the problems mentioned in the background art. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a highly efficient autotrophic denitrification system and method based on anaerobic ammonia oxidation, which solves the problems of long process flow, complex control, and difficulty in continuously maintaining the optimal ratio of ammonia nitrogen to nitrite nitrogen.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: A highly efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation, the system comprising a pretreatment module, a regulation module, an anaerobic ammonia oxidation reaction module, an adjustment and control module, a nitrogen element balance module, and a drainage and exhaust module connected in sequence; The pretreatment module is used to perform preliminary physical or chemical treatment on the input nitrogen-containing wastewater to remove large particles, oils and suspended solids, control the turbidity of the influent, and ensure the mass transfer efficiency of the subsequent biological reaction unit. The adjustment module is used to initially adjust the potential ratio of ammonia nitrogen and nitrite in the influent to avoid excessive instantaneous load leading to inhibition of anaerobic ammonia oxidation or substrate shortage. The anaerobic ammonia oxidation reaction module is the core of this system. It is set up with a short-cut nitrification zone and an anaerobic ammonia oxidation zone in sequence. It is used to convert part of the ammonia nitrogen into nitrite nitrogen, which then reacts with the remaining ammonia nitrogen in an anaerobic ammonia oxidation reaction to generate nitrogen gas. This module adopts a sludge morphology of flocculent-granular sludge coupling to optimize reaction efficiency and maintain biomass. The adjustment and control module includes an oxygen control submodule, a pH control submodule, a stirring and mixing submodule, and a temperature control submodule, which are used to monitor and automatically control the dissolved oxygen, pH, temperature and mixing conditions in the anaerobic ammonia oxidation reaction module in real time, so as to create the best metabolic environment for the functional microbial community. The nitrogen balance module is used to monitor the concentration changes of key nitrogen forms such as ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen online, evaluate the denitrification performance and nitrogen conversion pathway in real time, and provide a basis for decision-making to adjust the control module. The drainage and exhaust module includes a solid-liquid separation unit, an effluent monitoring tank, and a gas treatment unit. It is used to perform solid-liquid separation and water quality monitoring on the effluent after the reaction is completed, and to discharge the effluent in accordance with the standards. It also collects and treats the generated gas to render it harmless before discharging it.

[0007] Through the above technical solution, the core reaction of this autotrophic denitrification system and method does not rely on external organic carbon sources, thus reducing the huge carbon source addition costs in the denitrification process. At the same time, due to the slow growth and extremely low sludge production of anaerobic ammonia oxidizing bacteria, the cost of treating and disposing of excess sludge is significantly reduced. Furthermore, the various sub-modules of the intelligent control module can achieve relatively precise on-demand control, avoiding the waste of energy and reagents, and further reducing operating energy and material consumption. This achieves cost reduction and efficiency improvement from multiple dimensions. The system significantly reduces operating costs and resource consumption, and has outstanding economic advantages.

[0008] Furthermore, the pretreatment module employs one or more of the following methods: grid, screen, air flotation, flocculation, and coagulation, and adds flocculants or coagulants to remove large particles, grease, colloids, and suspended solids. The above technical solutions protect subsequent biological units, remove particulate matter and grease to prevent pipe and equipment blockage, reduce suspended solids and turbidity, significantly improve mass transfer efficiency, and ensure that substrates such as dissolved oxygen, ammonia nitrogen, and nitrite can be smoothly transferred to the surface of microbial cells in subsequent reactions, while avoiding the inhibition of functional flora by toxic and harmful substances.

[0009] Furthermore, the short-cut nitrification zone is the key control unit of this system, achieving stable and efficient short-cut nitrification through multi-parameter synergistic regulation. This zone employs a precise aeration strategy to strictly control dissolved oxygen within the micro-aerobic range of 0.1-0.5 mg / L, and maintains the optimal pH range of 7.0-8.0 and temperature range of 30-35°C. Under these conditions, ammonia-oxidizing bacteria are enriched while nitrite-oxidizing bacteria are inhibited, selectively oxidizing approximately 50%-60% of the influent ammonia nitrogen to nitrite nitrogen, forming a mixed liquor with a stable ammonia nitrogen to nitrite nitrogen molar ratio in the range of 1:1.2-1.4. This mixed liquor then enters the anaerobic ammonia oxidation zone, where the anaerobic ammonia oxidation reaction is completed under a strictly anaerobic environment. The above technical solutions avoid the impact of sudden high ammonia nitrogen loads on the subsequent biological system. Stable influent conditions are a key prerequisite for ensuring that the short-cut nitrification process can continuously and accurately produce the target proportion of nitrite.

[0010] Furthermore, the anaerobic ammonia oxidation reaction module adopts a sludge system in which flocculent sludge and granular sludge coexist; the short-cut nitrification zone is mainly composed of flocculent sludge, which is conducive to the attachment of ammonia-oxidizing bacteria and short-cut nitrification reaction; the anaerobic ammonia oxidation zone is mainly composed of granular sludge, which provides a protective microenvironment for the core anaerobic ammonia-oxidizing bacteria, enhances the bacteria's retention capacity and resistance to shock loads, and improves the overall denitrification rate and long-term operational stability of the system.

[0011] Furthermore, the anaerobic ammonia oxidation reaction module maintains the high activity of anaerobic ammonia oxidizing bacteria by controlling the carbon source input to an extremely low level, monitoring and regulating dissolved oxygen, pH and temperature parameters online, and supplementing the buffer system and trace elements.

[0012] Furthermore, the oxygen control submodule is configured to implement micro-oxygen control in the short-cut nitrification zone, with a dissolved oxygen concentration of 0.1-0.5 mg / L, and anaerobic control in the anaerobic ammonia oxidation zone, with a dissolved oxygen concentration below 0.1 mg / L; the pH control submodule is configured to maintain the system pH at 7.0-8.0; the temperature control submodule is configured to maintain the reaction temperature at 30-35°C; and the stirring and mixing submodule is used to employ a low-speed stirrer to ensure uniform distribution of sludge suspension and substrate within the reactor, preventing local inhibition. The above technical solutions fundamentally maintain its high metabolic activity and reaction rate. At the same time, the carbon source input is controlled at an extremely low level, and necessary trace elements are supplemented to eliminate competition from heterotrophic bacteria and ensure the absolute dominance of anaerobic ammonia oxidizing bacteria.

[0013] Furthermore, the nitrogen balance module acquires nitrogen speciation data through online sensors and offline water quality analysis; the module has a built-in nitrogen mass balance model to calculate short-range nitrification rate, anaerobic ammonia oxidation activity and total nitrogen removal rate; and combines gas monitoring data to generate control commands for optimizing system operation. Through the above technical solution, this module can diagnose the health status of the system in real time by tracking and quantitatively analyzing the entire nitrogen transformation pathway.

[0014] Furthermore, in the drainage and exhaust module, the supernatant after solid-liquid separation is discharged after being tested and found to meet the standards in the effluent monitoring tank, and some of the remaining sludge is returned to the anaerobic ammonia oxidation reaction module; the gas treatment unit includes a gas analyzer for monitoring and treating the nitrogen oxide components in the exhaust gas; The above technical solutions reduce nitrogen pollution and emissions of harmful gases.

[0015] (III) Beneficial Effects This invention provides a highly efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation. It has the following beneficial effects: 1. This invention provides a highly efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation. The core of this autotrophic nitrogen removal system and method lies in the seamless coupling of short-cut nitrification and anaerobic ammonia oxidation processes within a single reaction module. Through precise dissolved oxygen zoning control and optimal substrate ratio, ammonia nitrogen is directly and efficiently converted into nitrogen gas, thereby improving nitrogen removal efficiency and reducing sludge production rate. Furthermore, the synergistic system of flocculent-granular sludge within the anaerobic ammonia oxidation reaction module effectively enriches and retains functional microbial communities, enhancing the system's resistance to shock loads. The intelligent closed-loop control based on the nitrogen element balance model, through real-time monitoring and feedback regulation, ensures the long-term stability of the entire process and the optimization of treatment effects. This system achieves highly efficient, stable, and intelligent autotrophic nitrogen removal.

[0016] 2. This invention provides a highly efficient autotrophic denitrification system and method based on anaerobic ammonia oxidation. The core reaction of this autotrophic denitrification system and method does not rely on external organic carbon sources, thus reducing the huge carbon source addition costs in the denitrification process. At the same time, due to the slow growth and extremely low sludge production of anaerobic ammonia oxidizing bacteria, the cost of treating and disposing of excess sludge is significantly reduced. Furthermore, the intelligent control module enables relatively precise on-demand control of each sub-module, avoiding the waste of energy and reagents, further reducing operating energy and material consumption. This achieves cost reduction and efficiency improvement from multiple dimensions. The system significantly reduces operating costs and resource consumption, and has outstanding economic advantages.

[0017] 3. This invention provides a highly efficient autotrophic denitrification system and method based on anaerobic ammonia oxidation. This autotrophic denitrification system and method monitors and treats trace amounts of greenhouse gases in the exhaust gas through a gas treatment unit, thereby reducing greenhouse gas emissions. It can also efficiently recover nitrogen from wastewater and release it in the form of harmless nitrogen gas, thereby reducing nitrogen pollution. This autotrophic denitrification system and method have the characteristics of low energy consumption, low material consumption, and low sludge production. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the system flow of the present invention; Figure 2 This is a schematic diagram of the method flow of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example: This invention provides a highly efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation. The system includes a pretreatment module, a regulating module, an anaerobic ammonia oxidation reaction module, an adjustment and control module, a nitrogen balance module, and a drainage and exhaust module connected in sequence. The pretreatment module performs preliminary physical or chemical treatment on the input nitrogen-containing wastewater to remove large particles, oils, and suspended solids, control the influent turbidity, and ensure the mass transfer efficiency of subsequent biological reaction units. The regulating module is used to initially adjust the potential ratio of ammonia nitrogen to nitrite in the influent to avoid excessive instantaneous load leading to inhibition of anaerobic ammonia oxidation or substrate shortage. The anaerobic ammonia oxidation reaction module is the core of this system, internally containing a short-cut nitrification zone and an anaerobic ammonia oxidation zone. The anaerobic ammonia oxidation (AAO) module is used to convert ammonia nitrogen into nitrite nitrogen, which then reacts with the remaining ammonia nitrogen to generate nitrogen gas. This module uses a sludge morphology of flocculent-granular sludge coupling to optimize reaction efficiency and maintain biomass. The adjustment and control module includes an oxygen control submodule, a pH control submodule, a stirring and mixing submodule, and a temperature control submodule. These are used to monitor and automatically control dissolved oxygen, pH, temperature, and mixing conditions within the AAO module in real time, creating an optimal metabolic environment for the functional microbial community. The nitrogen balance module is used to monitor the concentration changes of key nitrogen forms such as ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen online, and to evaluate denitrification performance and nitrogen conversion pathways in real time, providing a decision-making basis for the adjustment and control module. The drainage and exhaust module includes a solid-liquid separation unit, an effluent monitoring tank, and a gas treatment unit. It is used to perform solid-liquid separation and water quality monitoring on the effluent after the reaction to ensure it meets discharge standards. It also collects and treats the generated gas before releasing it. The core reaction of this autotrophic denitrification system and method does not rely on external organic carbon sources, reducing the huge carbon source addition costs in the denitrification process. Simultaneously, due to the slow growth and extremely low sludge production of anaerobic ammonia-oxidizing bacteria, the cost of treating and disposing of excess sludge is significantly reduced. Furthermore, the intelligent control module's sub-modules can achieve relatively precise on-demand control, avoiding energy and reagent waste, further reducing operating energy and material consumption. This multi-dimensional approach achieves cost reduction and efficiency improvement, significantly reducing operating costs and resource consumption, and demonstrating outstanding economic advantages.

[0021] The pretreatment module employs one or more of the following methods: bar screen, sieve, flotation, flocculation, and coagulation, with the addition of flocculants or coagulants to remove large particles, grease, colloids, and suspended solids. This protects the subsequent biological units. Removing particulate matter and grease prevents pipe and equipment blockage, reduces suspended solids and turbidity, and significantly improves mass transfer efficiency. This ensures that dissolved oxygen, ammonia nitrogen, nitrite, and other substrates can be smoothly transferred to the surface of microbial cells in subsequent reactions, while avoiding the inhibition of functional flora by toxic and harmful substances. The short-cut nitrification zone is the key control unit of this system. Through multi-parameter synergistic regulation, it achieves stable and efficient short-cut nitrification. This zone uses a precise aeration strategy to strictly control dissolved oxygen within the micro-aerobic range of 0.1-0.5 mg / L, and maintains the optimal pH range of 7.0-8.0 and temperature range of 30-35°C. Under these conditions, ammonia-oxidizing bacteria are enriched while nitrite-oxidizing bacteria are inhibited, selectively oxidizing approximately 50%-60% of the influent ammonia nitrogen to nitrite nitrogen, forming... A mixed liquor with a stable ammonia nitrogen to nitrite nitrogen molar ratio of 1:1.2-1.4 is produced. This liquor then enters the anaerobic ammonia oxidation zone, where the anaerobic ammonia oxidation reaction is completed under strictly anaerobic conditions. This avoids the impact of sudden high ammonia nitrogen loads on the subsequent biological system. Stable influent conditions are a key prerequisite for ensuring the continuous and precise production of the target nitrite ratio during the short-cut nitrification process. The anaerobic ammonia oxidation reaction module adopts a sludge system in which flocculent sludge and granular sludge coexist. The short-cut nitrification zone is dominated by flocculent sludge, which is conducive to the attachment of ammonia-oxidizing bacteria and the short-cut nitrification reaction. The anaerobic ammonia oxidation zone is dominated by granular sludge, which provides a protective microenvironment for the core anaerobic ammonia-oxidizing bacteria, enhances the bacteria's retention capacity and resistance to shock loads, and improves the overall denitrification rate and long-term operational stability of the system. The anaerobic ammonia oxidation reaction module controls the carbon source input to an extremely low level and monitors and regulates dissolved oxygen, pH, and temperature parameters online. At the same time, it supplements the buffer system and trace elements to maintain the high activity of the anaerobic ammonia-oxidizing bacteria.

[0022] The oxygen control submodule is configured to implement micro-oxygen control in the short-cut nitrification zone, with a dissolved oxygen concentration of 0.1-0.5 mg / L, and anaerobic control in the anaerobic ammonia oxidation zone, with a dissolved oxygen concentration below 0.1 mg / L. The pH control submodule is configured to maintain the system pH at 7.0-8.0. The temperature control submodule is configured to maintain the reaction temperature at 30-35°C. The mixing submodule uses a low-speed stirrer to ensure uniform distribution of sludge suspension and substrate within the reactor, preventing local inhibition and thus maintaining high metabolic activity and reaction rate. Simultaneously, it controls carbon source input to extremely low levels and supplements necessary trace elements, eliminating heterotrophic bacteria competition and ensuring the absolute dominance of anaerobic ammonia oxidation bacteria, maintaining nitrogen balance. The module acquires nitrogen speciation data through online sensors and offline water quality analysis. It incorporates a nitrogen mass balance model to calculate short-range nitrification rate, anaerobic ammonia oxidation activity, and total nitrogen removal rate. Combined with gas monitoring data, it generates control commands to optimize system operation. Through full-process tracking and quantitative analysis of the nitrogen transformation pathway, the module can diagnose the system's health status in real time. In the drainage and exhaust modules, the supernatant after solid-liquid separation is discharged after passing quality standards in the effluent monitoring tank. Some of the remaining sludge is recycled to the anaerobic ammonia oxidation reaction module. The gas treatment unit includes a gas analyzer to monitor and treat nitrogen oxide components in the exhaust gas, thereby reducing nitrogen pollution and the emission of harmful gases.

[0023] Working principle: First, nitrogen-containing wastewater enters the pretreatment module and passes through mechanical filtration equipment such as screens and sieves to remove large particles. Then, by adding flocculants and coagulants and combining them with air flotation, the oil, colloids, and fine suspended solids in the wastewater form flocs and float or settle, thus being effectively separated. The core purpose is to protect the subsequent biological units. Removing particulate matter and oil can prevent pipe and equipment blockage, reduce suspended solids and turbidity, and significantly improve mass transfer efficiency. This ensures that dissolved oxygen, ammonia nitrogen, nitrite and other substrates can be smoothly transferred to the surface of microbial cells in subsequent reactions, while avoiding the inhibition of functional bacteria by toxic and harmful substances. Secondly, the pretreated wastewater enters the equalization tank of the equalization module. This module homogenizes the influent flow and quality through a certain retention time, and performs preliminary detection and adjustment of ammonia nitrogen concentration. The purpose is to equalize and buffer the process. The quality and flow of industrial or municipal wastewater often fluctuate. The equalization module, through its buffering effect, avoids the impact of instantaneous high ammonia nitrogen load on the subsequent biological system. Stable influent conditions (especially stable ammonia nitrogen concentration) are the key prerequisites for ensuring that the short-cut nitrification process can continuously and accurately produce the target ratio (1:1.32) of nitrite. Third, the adjusted water enters the front end of the anaerobic ammonia oxidation reaction module—the short-cut nitrification zone. The oxygen control submodule implements precise micro-aeration in this zone, strictly controlling dissolved oxygen at an extremely low level of 0.1-0.5 mg / L. Simultaneously, the temperature control and pH regulation submodules maintain the environment under conditions suitable for ammonia oxidizing bacteria but unfavorable to nitrite oxidizing bacteria (e.g., temperature 30-35°C, pH 7.0-8.0). Under low dissolved oxygen conditions, ammonia oxidizing bacteria have a higher affinity for oxygen than nitrite oxidizing bacteria, thus preferentially oxidizing ammonia nitrogen to nitrite nitrogen while inhibiting further oxidation of nitrite nitrogen to nitrate nitrogen by nitrite oxidizing bacteria. The goal is to precisely control the degree of oxidation, converting approximately 55% of the ammonia nitrogen, ultimately forming a mixed solution with an ammonia nitrogen:nitrite nitrogen ratio of approximately 1:1.32, providing an ideal "reaction substrate package" for the anaerobic ammonia oxidation reaction. This zone is dominated by flocculent sludge, which facilitates the attachment and renewal of ammonia oxidizing bacteria. Fourth, the mixed liquor from the short-cut nitrification zone is uniformly introduced into the adjacent strictly anaerobic ammonium oxidation zone under the action of the stirring and mixing submodule. The dissolved oxygen in this zone is controlled below 0.1 mg / L (ensuring by the oxygen control submodule). In this environment, the anaerobic ammonium oxidizing bacteria use the nitrite produced in step three as an electron acceptor and the remaining ammonia nitrogen as an electron donor to carry out the reaction. Under an absolutely anaerobic environment, anaerobic ammonia oxidizing bacteria perform the following reaction: ammonia nitrogen + 1.32 nitrite nitrogen → 1.02 nitrogen gas↑ + 0.26 nitrate nitrogen + water. This process does not require an organic carbon source, achieving true autotrophic denitrification, which greatly saves operating costs and carbon emissions. The main product is nitrogen gas, while a small amount of nitrate is also produced. This area is mainly composed of granular sludge, which provides a protective micro-ecology and strong biological retention capacity for the slow-growing and environmentally sensitive anaerobic ammonia oxidizing bacteria, and is the key to the long-term stable operation of the system. Fifth, the regulation module runs through the entire process of biological reaction, and the oxygen control submodule controls dissolved oxygen in different areas; The pH control submodule stabilizes the pH by adding acid-base buffer solutions. The temperature control submodule maintains a constant temperature through heat exchange; The mixing submodule ensures that sludge does not settle and that the substrate is evenly distributed. Oxyamine oxidizing bacteria are highly sensitive to dissolved oxygen, pH, and temperature. Precise control of these parameters is fundamental to maintaining their high metabolic activity and reaction rate. At the same time, controlling the carbon source input to an extremely low level and supplementing with necessary trace elements (such as iron) is to eliminate competition from heterotrophic bacteria and ensure the absolute dominance of anaerobic ammonia oxidizing bacteria. Sixth, the nitrogen balance module operates continuously. It monitors data such as ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, pH, and redox potential at each process node in real time through online sensors, and performs regular offline calibration analysis in the laboratory. The nitrogen mass balance model built into this module automatically calculates key performance indicators such as "short-range nitrification rate", "anaerobic ammonia oxidation activity", and "total nitrogen removal rate". By tracking and quantitatively analyzing the entire nitrogen transformation pathway, this module can diagnose the system's health status in real time. For example, if nitrite nitrogen accumulation is detected, it indicates insufficient anaerobic ammonia oxidation activity; if nitrate nitrogen is abnormally elevated, it means that short-cut nitrification has failed (nitrite oxidizing bacteria proliferate). Based on this analysis, the module will generate optimization instructions (such as "reduce the aeration rate in the short-cut nitrification zone" and "adjust the pH setpoint") and automatically feed them back to the control module, realizing an intelligent closed loop from "monitoring" to "control", enabling the system to have self-optimization capabilities. Seventh, the mixed liquor that has completed the denitrification reaction enters the solid-liquid separation unit (such as a sedimentation tank or membrane module) of the drainage and exhaust module to achieve sludge-water separation. Most of the supernatant enters the subsequent unit, while a portion of the excess sludge containing highly active anaerobic ammonia oxidation granular sludge is pumped back to the anaerobic ammonia oxidation reaction module. Since the growth of anaerobic ammonia oxidation bacteria is extremely slow (generation time is about 11 days), sludge return is a necessary means to maintain sufficient biomass in the reactor and ensure treatment capacity. It effectively prevents the loss of precious bacteria and improves the system's resistance to load shocks and start-up speed. Eighth, the separated supernatant enters the effluent monitoring tank for final water quality testing (such as total nitrogen, ammonia nitrogen, etc.) to ensure that it meets the standards before being discharged. The gas produced by the reaction (mainly nitrogen, containing trace amounts of byproduct N2O) is collected and transported to the gas treatment unit. The gas analyzer monitors its composition online. If harmful nitrogen oxides (such as N2O) are detected, the catalytic reduction and other treatment devices are activated to convert them into harmless nitrogen.

[0024] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A highly efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation, characterized in that: The system includes a pretreatment module, a regulation module, an anaerobic ammonia oxidation reaction module, an adjustment and control module, a nitrogen balance module, and a drainage and exhaust module connected in sequence. The pretreatment module is used to perform preliminary physical or chemical treatment on the input nitrogen-containing wastewater to remove large particles, oils and suspended solids, control the turbidity of the influent, and ensure the mass transfer efficiency of the subsequent biological reaction unit. The adjustment module is used to initially adjust the potential ratio of ammonia nitrogen and nitrite in the influent to avoid excessive instantaneous load leading to inhibition of anaerobic ammonia oxidation or substrate shortage. The anaerobic ammonia oxidation reaction module is the core of this system. It is set up with a short-cut nitrification zone and an anaerobic ammonia oxidation zone in sequence. It is used to convert part of the ammonia nitrogen into nitrite nitrogen, which then reacts with the remaining ammonia nitrogen in an anaerobic ammonia oxidation reaction to generate nitrogen gas. This module adopts a sludge morphology of flocculent-granular sludge coupling to optimize reaction efficiency and maintain biomass. The adjustment and control module includes an oxygen control submodule, a pH control submodule, a stirring and mixing submodule, and a temperature control submodule, which are used to monitor and automatically control the dissolved oxygen, pH, temperature and mixing conditions in the anaerobic ammonia oxidation reaction module in real time, so as to create the best metabolic environment for the functional microbial community. The nitrogen balance module is used to monitor the concentration changes of key nitrogen forms such as ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen online, evaluate denitrification performance and nitrogen conversion pathway in real time, and provide a basis for decision-making to adjust the control module. The drainage and exhaust module includes a solid-liquid separation unit, an effluent monitoring tank, and a gas treatment unit. It is used to perform solid-liquid separation and water quality monitoring on the effluent after the reaction is completed, and to discharge the effluent in accordance with the standards. It also collects and treats the generated gas to render it harmless before discharging it.

2. The efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation according to claim 1, characterized in that: The pretreatment module employs one or more of the following methods: grid, screen, air flotation, flocculation, and coagulation, and adds flocculants or coagulants to remove large particles, grease, colloids, and suspended solids.

3. The efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation according to claim 1, characterized in that: The short-cut nitrification zone is the key control unit of this system, achieving stable and efficient short-cut nitrification through multi-parameter coordinated regulation. This zone employs a precise aeration strategy to strictly control dissolved oxygen within the micro-aerobic range of 0.1-0.5 mg / L, and maintains the optimal pH range of 7.0-8.0 and temperature range of 30-35°C. Under these conditions, ammonia-oxidizing bacteria are enriched while nitrite-oxidizing bacteria are inhibited, selectively oxidizing approximately 50%-60% of the influent ammonia nitrogen to nitrite nitrogen, forming a mixed liquor with a stable ammonia nitrogen to nitrite nitrogen molar ratio of 1:1.2-1.

4. This mixed liquor then enters the anaerobic ammonia oxidation zone, where the anaerobic ammonia oxidation reaction is completed under strictly anaerobic conditions.

4. The efficient autotrophic denitrification system and method based on anaerobic ammonia oxidation according to claim 1, characterized in that: The anaerobic ammonia oxidation reaction module adopts a sludge system in which flocculent sludge and granular sludge coexist. The short-cut nitrification zone is mainly composed of flocculent sludge, which is conducive to the attachment of ammonia-oxidizing bacteria and short-cut nitrification reaction. The anaerobic ammonia oxidation zone is mainly composed of granular sludge, which provides a protective microenvironment for the core anaerobic ammonia-oxidizing bacteria, enhances the bacteria's retention capacity and resistance to shock loads, and improves the overall denitrification rate and long-term operational stability of the system.

5. The efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation according to claim 1, characterized in that: The anaerobic ammonia oxidation reaction module maintains the high activity of anaerobic ammonia oxidizing bacteria by controlling the carbon source input to an extremely low level and monitoring and regulating dissolved oxygen, pH and temperature parameters online, while supplementing the buffer system and trace elements.

6. The efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation according to claim 1, characterized in that: The oxygen control submodule is configured to implement micro-oxygen control in the short-cut nitrification zone, with a dissolved oxygen concentration of 0.1-0.5 mg / L, and anaerobic control in the anaerobic ammonia oxidation zone, with a dissolved oxygen concentration below 0.1 mg / L. The pH control submodule is configured to maintain the system pH at 7.0-8.

0. The temperature control submodule is configured to maintain the reaction temperature at 30-35°C. The stirring and mixing submodule is used to employ a low-speed stirrer to ensure uniform distribution of sludge suspension and substrate within the reactor, preventing local inhibition.

7. The efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation according to claim 1, characterized in that: The nitrogen balance module acquires nitrogen speciation data through online sensors and offline water quality analysis. The module has a built-in nitrogen mass balance model to calculate short-range nitrification rate, anaerobic ammonia oxidation activity, and total nitrogen removal rate. Combined with gas monitoring data, it generates control commands to optimize system operation.

8. The efficient autotrophic nitrogen removal system and method based on anaerobic ammonia oxidation according to claim 1, characterized in that: In the drainage and exhaust module, the supernatant after solid-liquid separation is discharged after being tested and found to meet the standards in the effluent monitoring tank, and some of the remaining sludge is returned to the anaerobic ammonia oxidation reaction module; the gas treatment unit includes a gas analyzer for monitoring and treating the nitrogen oxide components in the exhaust gas.

9. A highly efficient autotrophic nitrogen removal method based on anaerobic ammonium oxidation, characterized in that, Includes the following processes: S1. Physicochemical pretreatment of nitrogen-containing wastewater is carried out to remove large particles, grease and suspended solids, and the turbidity and toxic substances in the influent are strictly controlled to provide a clean influent substrate for short-cut nitrification. S2. Adjust the water quality and quantity of the pretreated wastewater, focusing on stabilizing the ammonia nitrogen concentration range to ensure that the ammonia nitrogen load entering the short-cut nitrification zone is relatively constant and to avoid shock loads; S3. Short-cut nitrification is carried out under strictly controlled micro-aerobic environment. Dissolved oxygen is maintained at 0.1-0.5 mg / L through precise aeration. Ammonia-oxidizing bacteria are selectively enriched, and about 55% of the ammonia nitrogen in the influent is converted into nitrite nitrogen, forming an ideal mixture with a molar ratio of ammonia nitrogen to nitrite nitrogen close to 1:1.

32. At the same time, the activity of nitrite-oxidizing bacteria is inhibited to prevent excessive oxidation. S4. The mixed liquor formed by short-cut nitrification is rapidly introduced into the adjacent strictly anaerobic ammonium oxidation zone, where anaerobic ammonium oxidizing bacteria convert ammonia nitrogen and nitrite nitrogen into nitrogen gas in stoichiometric ratio, thus completing autotrophic denitrification. S5. Maintain a sludge system dominated by flocculent sludge in the short-cut nitrification zone to provide a good attachment interface and mass transfer conditions for ammonia oxidizing bacteria; maintain a system dominated by granular sludge in the anaerobic ammonia oxidation zone to protect anaerobic ammonia oxidizing bacteria and enhance biological retention capacity. S6. Focus on monitoring and automatically control the short-cut nitrification zone, and precisely control dissolved oxygen, pH (7.0-8.0), temperature (30-35°C) and mixing conditions in real time to ensure the stability and efficiency of the short-cut nitrification process; S7. The nitrogen balance module focuses on monitoring the short-cut nitrification efficiency and nitrite accumulation. Based on the nitrogen mass balance model, key indicators such as short-cut nitrification rate and nitrite yield are calculated in real time. The operating parameters of the short-cut nitrification zone are dynamically adjusted to achieve intelligent closed-loop control with short-cut nitrification as the core. S8. Solid-liquid separation is performed on the mixed liquor after the reaction. The supernatant enters the subsequent treatment unit. Most of the granular sludge rich in anaerobic ammonia oxidizing bacteria is returned to the anaerobic ammonia oxidation zone, and a small amount of flocculent sludge can be returned to the short-cut nitrification zone to maintain biomass. S9. The separated supernatant is tested for water quality. If it meets the standards, it is discharged. The gas produced by the reaction (mainly nitrogen) is collected, and any trace amounts of nitrogen oxides that may be present are monitored and treated to render them harmless.

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