Short-cut nitrification coupled with anammox reactor for high organic nitrogen load

Abstract

The utility model discloses a short -path nitrification coupling anaerobic ammonia oxidation reactor for high organic nitrogen load relates to organic wastewater treatment technical field can be used for landfill leachate treatment and kitchen garbage marsh liquid treatment, the hydrolytic ammoniation jar of intercommunication of connection in proper order, oxygen -limited oxidation pond, anaerobic ammonia oxidation pond and cyclone sedimentation tank, and the light mud of cyclone sedimentation tank export and oxygen -limited oxidation pond between, the heavy mud of cyclone sedimentation tank export and anaerobic ammonia oxidation pond between all intercommunication have the branch point return line of pipe way. The utility model not only is strong to high organic nitrogen load adaptability, and the denitrogenization efficiency is high, especially to the organic nitrogen removal efficiency is high, and the reaction rate is fast, need not carbon source, and aeration energy consumption is low, and sludge production is less.

Description

Technical Field

[0001] This utility model relates to the field of organic wastewater treatment technology, and more specifically, to a short-cut nitrification coupled anaerobic ammonia oxidation reactor for high organic nitrogen loads, which is particularly suitable for treating organic wastewater containing high concentrations of organic nitrogen, such as landfill leachate and kitchen waste biogas slurry. Background Technology

[0002] Total nitrogen in wastewater consists of several forms of nitrogen: ① ammonia nitrogen It exists in the form of free ammonia or ammonium salts; ② Nitrate nitrogen Nitrite nitrogen is in oxidized form and is the final product of the nitration reaction; ④ Organic nitrogen, such as proteins and amino acids, needs to be decomposed into inorganic nitrogen. In addition, it may contain trace amounts of other nitrogen-containing compounds; various nitrogen forms can be removed through synergistic processes.

[0003] The traditional process for treating wastewater with high total nitrogen concentrations is the conventional nitrification-denitrification denitrification process. This process requires a large amount of aeration (consuming 60% of the plant's energy) and an external carbon source, resulting in high operating costs and a large sludge production. Single physicochemical or biological processes are difficult to reliably meet standards. While membrane deep treatment technology (reverse osmosis) can remove total nitrogen, this removal involves transferring total nitrogen to a concentrate via membrane separation, and the total nitrogen in the concentrate remains untreated.

[0004] In recent years, anaerobic ammonia oxidation (ANAO) technology has gradually gained attention in the wastewater treatment industry. ANAO offers significant advantages in treating high total nitrogen wastewater, especially in nitrogen removal: it requires no external carbon source, directly reacting with ammonia nitrogen and nitrite nitrogen as substrates, avoiding carbon source competition; it boasts high nitrogen removal efficiency, fast reaction rate, and high nitrogen removal load; it has low aeration energy consumption, requiring only about 50% of the aeration volume of traditional processes; it produces less sludge, reducing treatment costs by more than 30%; and it features a short process flow, small footprint, and efficient conversion of high ammonia nitrogen wastewater into nitrogen gas, achieving green and low-carbon nitrogen removal.

[0005] With the acceleration of urbanization in my country, the annual output of municipal solid waste exceeds 400 million tons, leading to a surge in the generation of high-organic-nitrogen wastewater such as landfill leachate and kitchen waste biogas slurry. This type of wastewater can have a total nitrogen concentration exceeding 2500 mg / L, with organic nitrogen accounting for over 35% (such as protein and urea); especially in landfill leachate, the organic nitrogen content can exceed 50%. High total nitrogen concentrations result in an imbalanced C / N ratio (usually <3) and significant fluctuations in water quality. Traditional denitrification processes and the emerging anaerobic ammonia oxidation (ANAO) process both face challenges, particularly the ANAO process, which is significantly affected in terms of denitrification efficiency, as detailed below: (1) Organic nitrogen (such as proteins, amino acids, etc.) needs to be converted into inorganic ammonia nitrogen before it can be utilized by the anammox process. In the anammox reactor, this process is not only slow, but also causes heterotrophic bacteria to compete with anammox bacteria, inhibiting the activity of anammox bacteria and even causing the anammox process to collapse.

[0006] (2) In the anaerobic ammonia oxidation reactor, due to the delayed conversion of organic nitrogen, the organic nitrogen that has not been converted into inorganic ammonia nitrogen will not participate in the subsequent denitrification reaction, and the subsequent reaction will be affected by insufficient ammonia nitrogen and nitrite. Reduced yield leads to a shortage of substrate for anaerobic ammonia oxidizing bacteria, resulting in a decrease in overall nitrogen removal efficiency.

[0007] (3) High COD (usually >5000 mg / L) in landfill leachate and kitchen waste biogas slurry will promote the proliferation of heterotrophic bacteria, compete for dissolved oxygen, and inhibit the activity of ammonia-oxidizing bacteria.

[0008] (4) Ammonia-oxidizing bacteria that undergo pre-short-cut nitrification require a relatively short sludge age (1-3 days) and a temperature of 30-35℃, while anaerobic ammonia-oxidizing bacteria require a long sludge age (15-20 days) and a temperature of 30-35℃. The two bacterial communities are contradictory in terms of sludge age. If the anaerobic ammonia-oxidizing bacterial community is to be maintained by sludge removal, it will lead to the loss of the anaerobic ammonia-oxidizing bacterial community and prevent its accumulation.

[0009] (5) Under high organic nitrogen load conditions, a high sludge concentration needs to be maintained in the reactor, so it is necessary to enhance the mass transfer between sludge and water. Traditional mechanical stirring has limited mass transfer effect, which will result in insufficient contact between nitrogen pollutants and sludge flocs attached to microbial communities, and dead zones will be formed in some areas due to uneven stirring; moreover, traditional mechanical stirring mass transfer will also bring dissolved oxygen, which will have an adverse effect on the anaerobic ammonia-oxidizing bacteria that need to grow in an oxygen-isolated environment.

[0010] (6) Although the anaerobic ammonia oxidation process theoretically saves 60% of energy, requires no carbon source, and reduces carbon by 50%, the existing anaerobic ammonia oxidation process generally faces the problems of load limitation and fear of fluctuation, especially when treating wastewater containing high concentrations of organic nitrogen.

[0011] Therefore, existing anaerobic ammonia oxidation processes have revealed many limitations when used to treat wastewater with high organic nitrogen loads, such as landfill leachate and kitchen waste biogas slurry. Utility Model Content

[0012] The purpose of this invention is to provide a short-cut nitrification coupled anaerobic ammonium oxidation reactor for high organic nitrogen loads. It is not only highly adaptable to high organic nitrogen loads, but also has high denitrification efficiency, fast reaction rate, no need for carbon source, low aeration energy consumption, and low sludge production.

[0013] To achieve the purpose of this utility model, the technical solution adopted is as follows: a short-cut nitrification coupled anaerobic ammonia oxidation reactor for high organic nitrogen load, comprising a hydrolysis ammonification tank, an oxygen-limited oxidation tank, an anaerobic ammonia oxidation tank and a cyclone sedimentation tank connected in sequence, and a branch return pipeline connecting the light sludge discharge outlet of the cyclone sedimentation tank with the oxygen-limited oxidation tank, and the heavy sludge discharge outlet of the cyclone sedimentation tank with the anaerobic ammonia oxidation tank.

[0014] Furthermore, both the hydrolysis ammoniation tank and the oxygen-limited oxidation tank are equipped with agitators.

[0015] Furthermore, the inlets of the hydrolysis ammoniation tank, the oxygen-limited oxidation tank, and the anaerobic ammonium oxidation tank are all located at their lower parts, while the outlets of the hydrolysis ammoniation tank, the oxygen-limited oxidation tank, and the anaerobic ammonium oxidation tank are all located at their upper parts.

[0016] Furthermore, the bottom of the oxygen-limited oxidation tank is also equipped with an aeration structure.

[0017] Furthermore, the lower part of the hydrolysis ammoniation tank, the oxygen-limited oxidation tank, and the anaerobic ammonium oxidation tank are all equipped with sludge discharge devices.

[0018] Furthermore, the anaerobic ammonia oxidation tank is provided with baffles arranged in an alternating pattern.

[0019] Furthermore, the oxygen-limiting oxidation tank and the anaerobic ammonia oxidation tank are covered with a composite insulation layer.

[0020] Furthermore, the composite insulation layer includes a polyurethane layer and a rock wool layer covering the polyurethane layer.

[0021] The beneficial effects of this utility model are: 1. This invention not only has strong adaptability to high organic nitrogen load, but also has high denitrification efficiency, fast reaction rate, no need for carbon source, low aeration energy consumption, and low sludge production.

[0022] 2. In this invention, a hydrolysis ammoniation tank is used to pretreat wastewater containing high concentrations of organic nitrogen, thereby converting macromolecular nitrogen-containing organic matter into ammonia nitrogen, providing a substrate for subsequent reactions, ensuring the continuous and smooth process of hydrolysis ammoniation-short-cut nitrification-anaerobic ammonium oxidation for total nitrogen removal, and improving nitrogen removal efficiency.

[0023] 3. By physically separating the short-cut nitrification and anaerobic ammonia oxidation reactions into two different tanks, the short-cut nitrifying bacteria and anaerobic ammonia oxidation bacteria can each have their own distinct growth and metabolic conditions and denitrification functions. This avoids the contradictions and differences between the short-cut nitrifying bacteria and anaerobic ammonia oxidation bacteria in terms of dissolved oxygen conditions, growth rates, and sludge age control. At the same time, strict microbial zoning control measures are implemented for the staged conversion of nitrogen forms (organic nitrogen → ammonia nitrogen → nitrite nitrogen → nitrogen gas), further optimizing the different functional bacteria so that each can "find its proper place and perform its own function," thereby improving denitrification efficiency.

[0024] 4. Hydrolysis ammoniation tanks, oxygen-limited oxidation tanks, and anaerobic ammonium oxidation tanks adopt an upflow flow design, which is more conducive to mud-water mixing. In particular, the anaerobic ammonium oxidation tank integrates multiple measures such as nitrogen airlift stirring + baffles to optimize mass transfer, promote the mixing of substrate and microbial community, not only improve the volumetric loading rate, but also adapt to high nitrogen loads and load fluctuations.

[0025] 5. The sludge-water separation is achieved through the swirling separation action of the sludge sedimentation tank, enabling differential separation of sludge density. The denser sludge enriched with anaerobic ammonia oxidizing bacteria can be sent back to the anaerobic ammonia oxidation tank to replenish these bacteria, while the lighter sludge enriched with heterotrophic bacteria can be selectively discharged or sent to a limited-oxygen oxidation tank to replenish short-cut nitrifying bacteria. This avoids excessive recirculation that could lead to competition among bacterial communities in the reaction tank. This design avoids the contradiction between "short-cut nitrifying bacteria needing increased sludge discharge and reduced sludge recirculation to maintain a short sludge age" and "anaerobic ammonia oxidizing bacteria needing reduced sludge discharge and increased sludge recirculation to accumulate bacterial communities and maintain a long sludge age." Furthermore, through the swirling-sedimentation separation function, the heavy sludge enriched with anaerobic ammonia oxidizing bacteria can be selectively recirculated to the anaerobic ammonia oxidation tank, increasing the concentration of anaerobic ammonia oxidizing bacteria. Attached Figure Description

[0026] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification.

[0027] Figure 1 This is a system diagram of a short-cut nitration coupled anaerobic ammonium oxidation reactor for high organic nitrogen loading provided by this utility model; Figure 2 This is a schematic diagram of the structure of an oxygen-limited oxidation pond; Figure 3 This is a schematic diagram of the structure of an anaerobic ammonia oxidation tank.

[0028] The attached diagram shows the markings and corresponding component names: 1. Hydrolysis ammoniation tank; 2. Oxygen-limited oxidation tank; 3. Anaerobic ammonium oxidation tank; 4. Cyclone sedimentation tank; 5. Branch point return pipeline. 11. Mixer; 21. Aeration structure; 31. Baffle plate. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0030] It should be noted that, where there is no conflict, the embodiments and features described in these embodiments can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] like Figures 1 to 3 As shown, this utility model provides a short-cut nitrification coupled anaerobic ammonium oxidation reactor for high organic nitrogen loading, comprising a hydrolysis ammonification tank 1, an oxygen-limited oxidation tank 2, an anaerobic ammonium oxidation tank 3, and a cyclone sedimentation tank 4 connected in sequence. The hydrolysis ammonification tank 1 is connected to an inlet pipe for feeding organic wastewater containing high concentrations of organic nitrogen into the hydrolysis ammonification tank 1, and the cyclone sedimentation tank 4 is connected to a drain pipe for discharging the liquid separated by cyclone separation. The hydrolysis ammonification tank 1 first processes the organic wastewater containing large molecules... Nitrogenous organic matter is broken down into smaller nitrogen-containing organic molecules, and these smaller nitrogen-containing organic molecules are deaminated by ammonifying bacteria to generate ammonia nitrogen. In the oxygen-limiting oxidation tank 2, ammonia nitrogen in the wastewater is oxidized to nitrite nitrogen through short-cut nitrification. In the anaerobic ammonia oxidation tank 3, ammonia nitrogen and nitrite nitrogen in the wastewater after short-cut nitrification are converted into nitrogen gas through anaerobic ammonia oxidation. The cyclone sedimentation tank 4 is used to separate sludge from water in the wastewater after anaerobic ammonia oxidation and to perform density-differential separation of the sludge.

[0032] Meanwhile, the light sludge outlet of the cyclone sedimentation tank 4 is connected to the oxygen-limited oxidation tank 2, and the heavy sludge outlet of the cyclone sedimentation tank 4 is connected to the anaerobic ammonia oxidation tank 3, both connected by branch return pipelines 5. Each branch return pipeline 5 is equipped with a sludge pump and regulating valve, allowing the light sludge from the cyclone sedimentation tank 4 after sludge-water separation to be replenished in accordance with the sludge age requirements of the oxygen-limited oxidation tank 2, and the heavy sludge from the cyclone sedimentation tank 4 after sludge-water separation to be replenished in accordance with the sludge age requirements of the anaerobic ammonia oxidation tank 3, thereby improving the sludge quality of the oxygen-limited oxidation tanks. The short-range nitrifying bacteria in tank 2 and the anaerobic oxidizing bacteria in tank 3 are supplemented to increase the volumetric loading rate. Since the anaerobic oxidizing bacteria in tank 3 require a long sludge age, the return flow rate can be controlled at 100% through the branch return pipeline 5 connecting tank 3 and cyclone sedimentation tank 4. This not only improves the sludge retention capacity in tank 3, but also maintains a sufficient biomass concentration in tank 3, so that the anaerobic oxidizing bacteria community can be stable and withstand high nitrogen loads to achieve efficient denitrification.

[0033] In this invention, a stirrer 11 is installed inside the hydrolysis ammoniation tank 1. The stirrer 11 stirs the wastewater in the hydrolysis ammoniation tank 1, which can further promote mass transfer and make the sludge and water fully mixed. At the same time, a stirrer 11 is also installed inside the oxygen-limited oxidation tank 2. The stirrer 11 stirs the wastewater in the oxygen-limited oxidation tank 2, which can further promote mass transfer and make the sludge and water fully mixed, thereby promoting the mixing of substrate and microbial community and improving the reaction efficiency in the oxygen-limited oxidation tank 2.

[0034] In this invention, the hydrolysis ammoniation tank 1, the oxygen-limited oxidation tank 2, and the anaerobic ammonium oxidation tank 3 all adopt a bottom-inlet and top-outlet design. That is, the inlets of the hydrolysis ammoniation tank 1, the oxygen-limited oxidation tank 2, and the anaerobic ammonium oxidation tank 3 are all located at their lower parts, and the outlets of the hydrolysis ammoniation tank 1, the oxygen-limited oxidation tank 2, and the anaerobic ammonium oxidation tank 3 are all located at their upper parts. By adopting a bottom-inlet and top-outlet design, the hydrolysis ammoniation tank 1, the oxygen-limited oxidation tank 2, and the anaerobic ammonium oxidation tank 3 in this invention allow the upward force of the water flow to interact with the shear force of the sludge, thereby promoting more thorough mixing of the sludge and water, facilitating the mixing of the substrate and the microbial community, optimizing mass transfer, and improving reaction efficiency.

[0035] In this invention, the bottom of the oxygen-limiting oxidation tank 2 is also provided with an aeration structure 21. The aeration holes on the aeration structure 21 are micropores, and the aeration structure 21 is connected to an air pump. The air pump provides compressed air to the aeration structure 21. The compressed air entering the aeration structure 21 is discharged from the aeration holes on the aeration structure 21, thereby achieving aeration.

[0036] In this invention, to facilitate the discharge of sludge from the hydrolysis ammoniation tank 1, the oxygen-limited oxidation tank 2, and the anammox oxidation tank 3, each of these tanks is equipped with a sludge discharge device at its lower part. This device can be either a sludge discharge pipe or a screw conveyor, depending on the requirements. When a screw conveyor is used, the input end of the screw conveyor on the hydrolysis ammoniation tank 1 extends into the hydrolysis ammoniation tank 1, the input end of the screw conveyor on the oxygen-limited oxidation tank 2 extends into the oxygen-limited oxidation tank 2, and the input end of the screw conveyor on the anammox oxidation tank 3 extends into the anammox oxidation tank 3. This allows the sludge from the hydrolysis ammoniation tank 1, the oxygen-limited oxidation tank 2, and the anammox oxidation tank 3 to be directly discharged via the corresponding screw conveyor when needed. Of course, the hydrolysis ammoniation tank 1 may not need to be equipped with a sludge discharge device. In order to avoid the proliferation of nitrite oxidizing bacteria in the sludge in the oxygen-limited oxidation tank 2 due to excessive sludge age, the sludge age in the oxygen-limited oxidation tank 2 needs to be maintained at 2 to 3 days. In order to facilitate the discharge of sludge in the oxygen-limited oxidation tank 2, the sludge discharge device on the oxygen-limited oxidation tank 2 can preferably be a screw conveyor. Since the sludge age in the anammox oxidation tank 3 needs to be maintained at 15 to 25 days, the sludge discharge device on the anammox oxidation tank 3 can also preferably be a screw conveyor, so that the screw conveyor can automatically send out the inert sludge in the anammox oxidation tank 3.

[0037] In this invention, both the oxygen-limiting oxidation tank 2 and the anaerobic ammonia oxidation tank 3 are rectangular tanks. The anaerobic ammonia oxidation tank 3 has staggered baffles 31 inside, which not only forms a serpentine flow channel inside the anaerobic ammonia oxidation tank 3, but also creates alternating "push-mixing" zones inside the anaerobic ammonia oxidation tank 3. This optimizes the mass transfer and reaction kinetics inside the anaerobic ammonia oxidation tank 3, enhances the turbulent mixing of mud and water, and avoids short-circuiting. At the same time, the baffles 31 can reduce the impact load through the "buffering effect" of the compartments, and reduce the inhibition of anaerobic ammonia oxidizing bacteria by excessively high local substrate concentration.

[0038] Since nitrogen gas is released during the anammox reaction in the wastewater within the anammox tank 3, an air-lift stirring mechanism can be used instead of a mechanical stirring structure. The air-lift effect of the nitrogen gas generated during the anammox reaction drives the sludge-water circulation and mixing within the tank 3. The design of the baffle plate 31 and the bottom-inlet, top-outlet drainage method enhances mixing and mass transfer, making it highly suitable for scenarios with high loads, large load fluctuations, and high sludge concentrations. This significantly promotes the mixing of substrates and microbial communities, avoiding localized dead zones. In this invention, the total nitrogen removal rate of wastewater after passing through the anammox tank can reach over 80%, and the treated effluent meets the current domestic emission standards.

[0039] In this invention, since both the short-cut nitrification reaction in the oxygen-limited oxidation tank 2 and the anammox reaction in the anammox oxidation tank 3 are exothermic reactions, and the reaction temperatures of both reactions need to be maintained at 30–35°C, a composite insulation layer can be applied to the outside of both the oxygen-limited oxidation tank 2 and the anammox oxidation tank 3. This composite insulation layer can be a combination of a polyurethane layer and a rock wool layer, i.e., it can be applied to the outside of both the oxygen-limited oxidation tank 2 and the anammox oxidation tank 3, while the rock wool layer can be directly applied over the polyurethane layer. Alternatively, in this invention, a polyurethane layer, a rock wool layer, or other insulation material layer can be applied only to the outside of the oxygen-limited oxidation tank 2 and the anammox oxidation tank 3.

[0040] The working principle of the short-cut nitrification coupled anaerobic ammonia oxidation reactor for high organic nitrogen loading is as follows: Step S1: Organic wastewater containing high concentrations of organic nitrogen, such as landfill leachate and kitchen waste biogas slurry, is fed into hydrolysis ammoniation tank 1 from the bottom and remains in the hydrolysis ammoniation tank 1 for 24 hours. Hydrolysis ammoniation tank 1 is a closed cylindrical tank. The organic wastewater containing high concentrations of organic nitrogen first passes through hydrolysis bacteria to break down large nitrogen-containing organic molecules such as proteins into smaller molecules such as amino acids and monosaccharides, and other large organic pollutants into smaller organic molecules. Then, the ammonification bacteria in the hydrolysis ammoniation tank 1 deaminate amino acids and nitrogen-containing monosaccharides to generate ammonia nitrogen. Finally, small-molecule organic pollutants (COD) are degraded under the action of facultative anaerobic heterotrophic bacteria. After the reaction is completed, not only can insufficient COD degradation avoid competition for heterotrophic bacteria in subsequent short-cut nitrification and anaerobic ammonia oxidation reactions, but also the conversion of large-molecule nitrogen-containing organic matter into ammonia nitrogen is necessary for it to participate in subsequent short-cut nitrification and anaerobic ammonia oxidation denitrification reactions, thus providing usable ammonia nitrogen for subsequent reactions.

[0041] Step S2: The wastewater treated in step S1 is sent to oxygen-limited oxidation tank 2 and retained in it for 24 hours. During this retention period, the wastewater is aerated through the micropores in the oxygen-limited oxidation tank 2 to maintain dissolved oxygen levels, limiting them to 0.5–1 mg / L. These dissolved oxygen conditions are suitable for the growth and metabolism of short-cut nitrification. Simultaneously, the short-cut nitrifying bacteria in the oxygen-limited oxidation tank 2 reduce some of the ammonia nitrogen in the wastewater. Oxidized to nitrite nitrogen This provides substrates for the subsequent anaerobic ammonia oxidation reaction. In this step, if dissolved oxygen exceeds 1 mg / L, it will promote the growth of nitrite-oxidizing bacteria. The growth of these bacteria will not only lead to increased nitrite nitrogen... Oxidized to nitrate nitrogen This causes the subsequent anaerobic ammonia oxidation reaction to stop, as well as the competition between nitrite oxidizing bacteria and short-range nitrifying bacteria, which inhibits the short-range nitrifying bacteria. Therefore, dissolved oxygen in oxygen-limited oxidation tank 2 needs to be strictly controlled at 0.5-1 mg / L.

[0042] Step S3: The wastewater treated in step S2 is sent to anaerobic ammonia oxidation tank 3 and retained in anaerobic ammonia oxidation tank 3 for 168 hours. During the retention period in anaerobic ammonia oxidation tank 3, the wastewater is dominated by anaerobic ammonia oxidizing bacteria. The growth and metabolic reactions of anaerobic ammonia oxidizing bacteria must be carried out under strict anaerobic conditions (dissolved oxygen ≤ 0.2 mg / L). Under the action of anaerobic ammonia oxidizing bacteria, most of the ammonia nitrogen in the wastewater is eliminated. and most nitrite nitrogen Nitrogen gas (N2) is generated and released, thereby achieving denitrification. In this step, the temperature within the anaerobic ammonia oxidation tank 3 is maintained at 30–35°C, and the wastewater flows in a serpentine pattern within the tank. Since nitrogen is an inert gas, it can be used as a stirring medium during release, avoiding the intake of dissolved oxygen caused by mechanical stirring and maintaining the anaerobic environment within the tank 3. Simultaneously, the uniform distribution of nitrogen bubbles improves the contact efficiency between the substrate and microorganisms during the rising and stirring process, optimizing mass transfer. By using air-lift stirring instead of mechanical stirring, sludge shear damage is effectively avoided, and air-lift stirring has low energy consumption, only half that of mechanical stirring.

[0043] Step S4: The wastewater treated in step S3 is sent to a cyclone sedimentation tank 4 and retained in the cyclone sedimentation tank 4 for 2 hours. The wastewater undergoes cyclone-sedimentation in the cyclone sedimentation tank 4, thereby promoting sludge-water separation. At the same time, the light sludge separated by cyclone-sedimentation in the cyclone sedimentation tank 4 is returned to the oxygen-limited oxidation tank 2, and the heavy sludge separated by cyclone-sedimentation in the cyclone sedimentation tank 4 is returned to the anaerobic ammonia oxidation tank 3. The amount of light sludge returned to the oxygen-limited oxidation tank 2 is adjusted according to the sludge age requirements in the oxygen-limited oxidation tank 2, and the amount of heavy sludge returned to the anaerobic ammonia oxidation tank 3 is adjusted according to the sludge age requirements in the anaerobic ammonia oxidation tank 3. This replenishes the short-range nitrifying bacteria in the oxygen-limited oxidation tank 2 and the anaerobic ammonia oxidizing bacteria in the anaerobic ammonia oxidation tank 3, thereby increasing the volumetric loading rate.

[0044] Meanwhile, during the process of returning the heavy sludge separated by swirling sedimentation in the swirl sedimentation tank 4 to the anaerobic ammonia oxidation tank 3, the return flow rate can be controlled at 100%. This can maintain a sufficient biomass concentration in the anaerobic ammonia oxidation tank 3, stabilize the functional microbial community, and thus withstand high nitrogen loads and achieve efficient denitrification.

[0045] In this invention, a vortex sedimentation tank 4 is used for vortex separation, which can achieve differential separation of sludge density, that is, separating sludge with higher density but enriched with anaerobic ammonia oxidizing bacteria and sludge with lower density but enriched with heterotrophic bacteria. In this invention, by selectively discharging the sludge enriched with heterotrophic bacteria, it is possible to avoid competition between the bacterial communities in the oxygen-limited oxidation tank 2 and the anaerobic ammonia oxidation tank 3 after excessive recirculation. Meanwhile, the heavy sludge enriched with anaerobic ammonia oxidizing bacteria is selectively recirculated to the anaerobic ammonia oxidation tank 3, which is more conducive to increasing the concentration of functional bacteria in the anaerobic ammonia oxidation tank 3 and maintaining the long sludge age required by anaerobic ammonia oxidizing bacteria.

[0046] In this invention, hydrolyzing bacteria, by secreting hydrolytic enzymes, decompose complex macromolecular organic matter into small soluble substrates. They act as the "first line of defense" in the anaerobic reaction, breaking down the structure of recalcitrant organic matter in wastewater. This provides the necessary conditions for subsequent ammoniation of small organic nitrogen molecules and further degradation of small organic molecules, making it a crucial prerequisite for the efficient operation of the entire anaerobic reaction. Simultaneously, the core function of hydrolyzing bacteria is to "decompose macromolecular organic matter into small organic molecules." Organic wastewater is rich in complex macromolecular organic matter such as cellulose, hemicellulose, starch, protein, fat, and large organic nitrogen molecules. Without the action of hydrolyzing bacteria to break these down into smaller molecules, subsequent degradation and ammoniation would be impossible. In other words, hydrolyzing bacteria are the "initiators" of the anaerobic reaction; their function and community structure directly determine the degradation efficiency of organic wastewater and the overall performance of the system, making them one of the core functional bacterial groups in the anaerobic reaction.

[0047] Taking the treatment of a certain food waste biogas slurry as an example: the total nitrogen of this food waste biogas slurry is 2750 mg / L, of which organic nitrogen is as high as 1245 mg / L. After the biogas slurry is treated by the short-cut nitrification coupled anaerobic ammonia oxidation reactor for high organic nitrogen load provided by this utility model, the total nitrogen of the effluent is 36 mg / L, of which organic nitrogen is 11 mg / L.

[0048] Those skilled in the art should understand that the above embodiments are merely for clearly illustrating the present invention and are not intended to limit the scope of the present invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A short-cut nitrification coupled with anaerobic ammonium oxidation reactor for high organic nitrogen loading, characterized in that, The system includes a hydrolysis ammoniation tank (1), an oxygen-limited oxidation tank (2), an anaerobic ammonia oxidation tank (3), and a vortex sedimentation tank (4) connected in sequence. The light sludge discharge outlet of the vortex sedimentation tank (4) is connected to the oxygen-limited oxidation tank (2), and the heavy sludge discharge outlet of the vortex sedimentation tank (4) is connected to the anaerobic ammonia oxidation tank (3) via a branch return pipeline (5).

2. The short-cut nitrification coupled anaerobic ammonium oxidation reactor for high organic nitrogen loading according to claim 1, characterized in that, Both the hydrolysis ammoniation tank (1) and the oxygen-limited oxidation tank (2) are equipped with a stirrer (11).

3. The short-cut nitrification coupled anaerobic ammonium oxidation reactor for high organic nitrogen loading according to claim 1, characterized in that, The inlets of the hydrolysis ammoniation tank (1), the oxygen-limited oxidation tank (2), and the anaerobic ammonium oxidation tank (3) are all located at their lower parts, and the outlets of the hydrolysis ammoniation tank (1), the oxygen-limited oxidation tank (2), and the anaerobic ammonium oxidation tank (3) are all located at their upper parts.

4. The short-cut nitrification coupled anaerobic ammonium oxidation reactor for high organic nitrogen loading according to claim 1, characterized in that, The bottom of the oxygen-limited oxidation tank (2) is also equipped with an aeration structure (21).

5. The short-cut nitrification coupled anaerobic ammonium oxidation reactor for high organic nitrogen loading according to claim 1, characterized in that, The lower part of the hydrolysis ammoniation tank (1), the oxygen-limited oxidation tank (2), and the anaerobic ammonium oxidation tank (3) are all equipped with sludge discharge devices.

6. The short-cut nitrification coupled anaerobic ammonium oxidation reactor for high organic nitrogen loading according to claim 1, characterized in that, The anaerobic ammonia oxidation tank (3) is provided with baffles (31) arranged in an alternating pattern.

7. The short-cut nitrification coupled anaerobic ammonium oxidation reactor for high organic nitrogen loading according to any one of claims 1 to 6, characterized in that, The oxygen-limiting oxidation tank (2) and the anaerobic ammonia oxidation tank (3) are covered with a composite insulation layer.

8. The short-cut nitrification coupled anaerobic ammonium oxidation reactor for high organic nitrogen loading according to claim 7, characterized in that, The composite insulation layer includes a polyurethane layer and a rock wool layer covering the polyurethane layer.

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