Biological denitrification reaction device

Abstract

The utility model discloses a biological denitrification reaction device which comprises a reflux zone, and a pre-anaerobic zone, a weak aeration aerobic zone, a strong aeration aerobic zone and a settling zone which are sequentially communicated along the flow direction of muddy water, the settling zone is provided with a sludge outlet and a water outlet; the reflux zone is communicated with the sludge outlet and the pre-anaerobic zone and is used for controlling the sludge concentration of the mixed liquid in the pre-anaerobic zone to be greater than or equal to 6g / L; the reflux zone is communicated with the weak aeration aerobic zone and is used for controlling the sludge concentration of the mixed liquid in the weak aeration anaerobic zone to be greater than or equal to 6g / L; a first aeration device and a first dissolved oxygen detection device are arranged in the weak aeration aerobic zone and are used for controlling the dissolved oxygen content in the weak aeration aerobic zone to be less than 0.5 mg / L; a second aeration device is arranged in the strong aeration aerobic zone and is used for controlling the dissolved oxygen content in the strong aeration aerobic zone to be greater than or equal to 1.0 mg / L. According to the utility model, the air supply quantity and the water inlet flow are controlled through the feedback of dissolved oxygen and the accumulation condition of nitrite concentration, so as to maintain the stable operation of the system.

Description

Technical Field

[0001] The utility model relates to the technical field of sludge treatment methods, in particular to a biological denitrification reaction device. Background Art

[0002] The removal of pollutants such as ammonia nitrogen and total nitrogen in wastewater requires aerobic treatment. The current mainstream aerobic technology is basically heterotrophic denitrification, but the cost of heterotrophic denitrification to achieve good denitrification effects is high. Therefore, autotrophic denitrification, which is more energy-saving and consumption-reducing, has received widespread attention in wastewater treatment. The current autotrophic denitrification needs to be developed and verified through the development of new equipment to achieve the flexibility of equipment process changes, and is conducive to the development of short-range nitrification-anaerobic ammonia oxidation processes. As a new type of biological denitrification technology, anaerobic ammonia oxidation does not rely on organic carbon sources during the denitrification process, and only needs to oxidize 50% of the ammonia. Its biological growth rate, sludge production, and aeration energy consumption are lower than those of traditional nitrification / denitrification processes. In terms of denitrification load, the overall load of the anaerobic ammonia oxidation process is higher than that of the traditional A / 0 process, and the denitrification rate is greater than 1.0 kg / m 3 *d, while the denitrification rate of traditional A / O process generally does not exceed 0.5kg / m 3 *d. Therefore, this technology has great advantages in saving the land and construction cost of denitrification reactors. In terms of energy consumption, since this process does not require high-intensity aeration and a large proportion of reflux, its operating energy consumption is also much lower than that of traditional processes. Taking advantage of the high potential nitrogen content of wastewater is conducive to the study of anaerobic ammonium oxidation technology and its stable regulation method.

[0003] Most of the current denitrification reaction devices have the following problems: 1) Due to defects in the device, it is impossible to (continuously) meet the environmental requirements of autotrophic nitrifying bacteria and anaerobic ammonium oxidizing bacteria, resulting in stability problems in the short-range nitrification-anaerobic ammonium oxidation process; 2) There is a lack of regulation of the system. Utility Model Content

[0004] In order to solve the problems existing in the above-mentioned prior art, a biological denitrification reaction device is provided, which realizes the regulation of influent ratio, influent load and operating parameters by regulating two variable factors of online micro-dissolved oxygen and nitrite accumulation, so as to quickly enrich nitrifying bacteria and anaerobic ammonia-oxidizing bacteria, achieve the effect of autotrophic denitrification, save carbon source and reduce energy consumption, and ensure the stability of the whole system at the same time.

[0005] The utility model provides the following technical solutions:

[0006] The utility model provides a biological denitrification reaction device, comprising a pre-anaerobic zone, a weak aeration aerobic zone, a strong aeration aerobic zone and a sedimentation zone which are sequentially connected along the flow direction of mud and water; the sedimentation zone is provided with a sludge outlet and a drain outlet; the utility model also comprises a reflow zone, the reflow zone is connected with the sludge outlet, the reflow zone is connected with the pre-anaerobic zone, and is used to control the sludge concentration of the mixed liquid in the pre-anaerobic zone to be ≥6g / L; the reflow zone is connected with the strong aeration aerobic zone, and is used to control the sludge concentration of the mixed liquid in the strong aeration aerobic zone to be ≥6g / L; the weak aeration aerobic zone is provided with a first aeration device and a first dissolved oxygen detection device, and is used to control the dissolved oxygen content in the weak aeration aerobic zone to be less than 0.5mg / L; the strong aeration aerobic zone is provided with a second aeration device, and is used to control the dissolved oxygen content in the strong aeration aerobic zone to be ≥1.0mg / L.

[0007] Furthermore, the pre-anaerobic zone is provided with a sludge inlet and a water inlet for achieving complete mixing of the sludge and the influent combined with the mud-water mixture.

[0008] Furthermore, a second pH detection device is also provided in the weakly aerated aerobic zone.

[0009] Furthermore, a first stirring device is provided in the weakly aerated aerobic zone to achieve a combination of intermittent stirring and aeration.

[0010] Furthermore, the strong aeration aerobic zone is mainly aerated, and pollutants such as ammonia nitrogen and COD remaining in the wastewater are removed by strong aeration.

[0011] Furthermore, the sedimentation zone separates the sludge and the supernatant through mud-water separation, thereby draining the water.

[0012] Furthermore, the sludge in the sedimentation zone flows back to the pre-anaerobic zone and the weakly aerated aerobic zone through the recirculation zone to ensure the sludge concentration in the sludge mixed liquor. The moisture content of the sludge in the recirculation zone is 97-98%.

[0013] Furthermore, the pH detection device is used to detect the pH value of the system so that it is within a suitable range required for microbial growth. The oxidation-reduction potential detection device is used to monitor the changes in the anoxic environment and aerobic environment of each reaction zone. Preferably, the pH of the system is 6.5-7.5.

[0014] Furthermore, the pH detection device is a pH detector, the dissolved oxygen detection device is an online dissolved oxygen meter; the oxidation-reduction potential detector.

[0015] Furthermore, an anaerobic zone is connected between the pre-anaerobic zone and the weakly aerated aerobic zone, and a first pH detection device and a first oxidation-reduction potential detection device are provided in the anaerobic zone. The anaerobic zone receives the muddy-water mixture from the pre-anaerobic zone, and the muddy-water mixture, in the presence of the organic carbon source of the wastewater, realizes the release of phosphorus and the consumption of the organic carbon source, reduces the impact on the autotrophic denitrification bacteria in the anoxic zone I and the anoxic zone II at the rear end, and ensures the subsequent reaction effect.

[0016] Furthermore, anoxic zone I and anoxic zone II are provided between the anaerobic zone and the weakly aerated aerobic zone, and the anaerobic zone, anoxic zone I, anoxic zone II, and weakly aerated aerobic zone are sequentially connected. The dissolved oxygen content of the anoxic zone I is 0.1-0.2 mg / L, and the dissolved oxygen content of the anoxic zone II is ≤0.1 mg / L.

[0017] Furthermore, a second stirring device is provided in the anoxic zone I. The anoxic zone I continues to consume the organic carbon source through intermittent stirring to complete the denitrification of part of the heterotrophic denitrifying bacteria.

[0018] Furthermore, a third stirring device is provided in the anoxic zone II. The anoxic zone II provides sufficient conditions to complete the complete reaction of ammonia nitrogen and nitrite under the condition of a lower carbon-nitrogen ratio (C / N) through intermittent stirring, and achieves the maximum effect of autotrophic denitrification in the absence of an organic carbon source.

[0019] Furthermore, the anoxic zone II is also provided with a second dissolved oxygen detection device and a second redox potential detection device.

[0020] Furthermore, the volume ratio of the anoxic zone I to the anoxic zone II is 5:8; and the volume ratio of the weakly aerated aerobic zone to the strongly aerated aerobic zone is 4:1.

[0021] A selection zone is provided between the anaerobic zone and the anoxic zone I, and the anaerobic zone, the selection zone and the anoxic zone I are sequentially connected. The selection zone can increase the residence time of oxygen release and reduce the influence of dissolved oxygen in the sludge after return flow on the autotrophic denitrification bacteria.

[0022] Furthermore, the total effective volume of the device is 90.93m 3 , the residence time is 21.82h.

[0023] Furthermore, the pool capacity of the selection area is 2.18m 3 , the mixed liquor depth is 2.6m, the retention time is 0.52h; the tank capacity of the anaerobic zone is 7.18m 3 , the mixed liquor depth is 2.6m, the residence time is 1.72h; the pool capacity of the anoxic zone I is 15m 3 The mixed liquid depth is 2.6m and the residence time is 3.6h; the pool capacity of the anoxic zone II is 24m 3, the mixed liquid depth is 2.6m, the residence time is 5.76h; the tank capacity of the weak aeration aerobic zone is 34.056m 3 , the mixed liquid depth is 2.7m, the residence time is 8.176h; the tank capacity of the strong aeration aerobic zone is 8.514m 3 , the mixed liquid depth is 2.7m and the residence time is 2.044h.

[0024] Furthermore, it also includes a stable sedimentation zone, which is arranged between the sedimentation zone and the strong aeration aerobic zone and is connected to the sedimentation zone and the strong aeration aerobic zone respectively.

[0025] Furthermore, it also includes an equipment room, in which an electric control cabinet and a blower are arranged. Two blowers are arranged, which are respectively connected to the first aeration device and the second aeration device for air supply; the electric control cabinet is respectively electrically connected to the blower, the aeration device, the dissolved oxygen detection device, the pH detection device, the oxidation-reduction potential detection device and the stirring device, and can control the air volume and frequency of the blower, the time period of system aeration, and the frequency and period of the stirring device according to the data fed back by the pH detection device, the oxidation-reduction potential detection device and the dissolved oxygen detection device, so as to realize the regulation of parameters such as the air supply volume of the system.

[0026] The beneficial technical effects of the utility model are:

[0027] 1) The biological denitrification reaction device of the utility model controls the air supply and water flow rate through the feedback of dissolved oxygen and the detection of the accumulation of nitrite concentration in the mixed solution of the weak aeration aerobic zone and the strong aeration aerobic zone, so that the weak aeration aerobic zone can achieve a dissolved oxygen operation below 0.5 mg / L, and the strong aeration aerobic zone can achieve a high dissolved oxygen operation of not less than 1 mg / L, so as to maintain the stable operation of the system;

[0028] 2) Further, by setting up the anaerobic zone, anoxic zone I and anoxic zone II that are connected in sequence between the pre-anaerobic zone and the weak aerated aerobic zone, the muddy water flows to the pre-anaerobic zone, the anaerobic zone, the selection zone, the anoxic zone I, the anoxic zone II, the weak aerated aerobic zone, the strong aerated aerobic zone and the sedimentation zone in sequence, and the inverted A2O design is realized, so that the removal of total nitrogen can only be done by biological methods, the total phosphorus can rely on subsequent deep treatment, and the carbon source is prioritized to ensure the utilization of total nitrogen; the technical advantages of low oxygen process energy saving and synchronous denitrification can be maximized, and the high aerated aerobic zone set after the low oxygen can ensure that the effluent ammonia nitrogen and organic matter will not exceed the standard;

[0029] 3) Furthermore, through the synergistic effect of each reaction zone, the system has a good denitrification effect and a fast startup. Nitrifying bacteria and anaerobic ammonia oxidizing bacteria come from traditional municipal activated sludge or natural water and soil. In order to ensure the rapid startup of the process, the mixed liquid in the device is maintained at a sufficient sludge concentration (≥6g / L) through the recirculation zone, and in the initial startup, the reaction device maintains a certain total nitrogen concentration (≥120mg / L) by adding urea. The dissolved oxygen in the initial strong aeration aerobic zone gradually decreases from 4-5mg / L to 1-2mg / L, and the enrichment of AOB nitrifying bacteria is achieved through the accumulation of nitrite; by arranging a stirring device in the anoxic zone I and the anoxic zone II to maintain an intermittent stirring state, the growth of autotrophic bacteria under suitable environmental conditions is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is a schematic structural diagram of a biological denitrification reaction device provided in an embodiment of the utility model.

[0032] Figure 2 This is a diagram showing the operation effect of the biological denitrification reaction device provided in an embodiment of the utility model.

[0033] Description of the symbols in the figure:

[0034] 1- Equipment room; 2- Pre-anaerobic zone; 3- Anaerobic zone; 301- First redox potential detector; 302- First pH detector; 4- Selection zone; 5- Anoxic zone I; 6- Anoxic zone II; 601- Second online dissolved oxygen meter; 602- Second redox potential detector; 7- Weak aeration aerobic zone; 701- First online dissolved oxygen meter; 702- Second pH detector; 8- Strong aeration aerobic zone; 9- Steady sedimentation zone; 10- Sedimentation zone; 11- Reflux zone. DETAILED DESCRIPTION

[0035] The following will be combined with the embodiments of the utility model to clearly and completely describe the technical solution of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0036] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0037] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0038] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] Please refer to Figure 1 The biological denitrification reaction device shown in the figure comprises an equipment room 1 and a pre-anaerobic zone 2, an anaerobic zone 3, a selection zone 4, anoxic zone I 5, anoxic zone II 6, a weak aeration aerobic zone 7, a strong aeration aerobic zone 8, a steady settling zone 9 and a sedimentation zone 10 which are sequentially connected along the mud and water flow direction; the sedimentation zone 10 is provided with a sludge outlet and a drain outlet; and further comprises a reflow zone 11 which is connected to the sludge outlet and is connected to the pre-anaerobic zone 2 for controlling the mixing in the pre-anaerobic zone 2. The mixed liquid sludge concentration is ≥6g / L; the reflow zone 11 is connected to the strong aeration aerobic zone 8, which is used to control the mixed liquid sludge concentration in the strong aeration aerobic zone 8 to be ≥6g / L; the weak aeration aerobic zone 7 is provided with a first aeration device and a first online dissolved oxygen meter 701, which are used to control the dissolved oxygen content in the weak aeration aerobic zone 7 to be <0.5mg / L; the strong aeration aerobic zone 8 is provided with a second aeration device, which is used to control the dissolved oxygen content in the strong aeration aerobic zone 8 to be ≥1.0mg / L.

[0040] Specifically, the anaerobic zone 3 is provided with a first pH detector 302 and a first oxidation-reduction potential detector 301. The anaerobic zone 3 receives the mud-water mixture from the pre-anaerobic zone 2. The mud-water mixture, in the presence of the wastewater organic carbon source, realizes the release of phosphorus and the consumption of the organic carbon source, reduces the impact on the autotrophic denitrification bacteria in the rear-end anoxic zone I 5 and anoxic zone II 6, and ensures the subsequent reaction effect.

[0041] Specifically, a second stirring device is provided in the anoxic zone I 5. The anoxic zone I 5 continues to consume the organic carbon source through intermittent stirring to complete the denitrification of part of the heterotrophic denitrifying bacteria.

[0042] Specifically, the anoxic zone II 6 is provided with a second online dissolved oxygen meter 601 and a second redox potential detector 602 .

[0043] Specifically, a third stirring device is also provided in the anoxic zone II 6. The anoxic zone II 6 provides sufficient conditions to complete the complete reaction of ammonia nitrogen and nitrous acid under a low carbon-nitrogen ratio (C / N) through intermittent stirring, and achieves the maximum effect of autotrophic denitrification in the absence of an organic carbon source.

[0044] Specifically, a second pH detector is also provided in the weakly aerated aerobic zone 7 .

[0045] Specifically, a first stirring device is further provided in the weakly aerated aerobic zone 7 to achieve a combination of intermittent stirring and aeration.

[0046] Specifically, the sedimentation area 10 separates the sludge and the supernatant through mud-water separation, thereby draining the water.

[0047] Specifically, the sludge in the sedimentation zone 10 is returned to the pre-anaerobic zone 2 and the weakly aerated aerobic zone 7 through the return zone 11 to ensure that the sludge concentration in the sludge mixture is ≥6 g / L, thereby completing the autotrophic denitrification of the wastewater and realizing the circulation of the sludge.

[0048] Specifically, the moisture content of the sludge in the recirculation zone 11 is 97%-98%.

[0049] Specifically, the total effective volume of the device is 90.93m 3 , the residence time is 21.82h.

[0050] Specifically, the tank capacity of the selected zone 4 is 2.18m3, the mixed liquor depth is 2.6m, and the residence time is 0.52h; the tank capacity of the anaerobic zone 3 is 7.18m3, the mixed liquor depth is 2.6m, and the residence time is 1.72h; the tank capacity of the anoxic zone I 5 is 15m3, the mixed liquor depth is 2.6m, and the residence time is 3.6h; the tank capacity of the anoxic zone II 6 is 24m3, the mixed liquor depth is 2.6m, and the residence time is 5.76h; the tank capacity of the weakly aerated aerobic zone 7 is 34.056m3, the mixed liquor depth is 2.7m, and the residence time is 8.176h; the tank capacity of the strongly aerated aerobic zone 8 is 8.514m3, the mixed liquor depth is 2.7m, and the residence time is 2.044h.

[0051] Specifically, a control system is provided in the equipment room 1, which can control the water inlet flow rate and the air supply volume of the aeration device according to the data fed back by the pH detector, the redox potential detector and the online dissolved oxygen meter.

[0052] The startup effect of the utility model was verified by a 75-day continuous experiment to test the concentrations of inlet ammonia nitrogen, outlet ammonia nitrogen, inlet nitrite (inlet nitrite), outlet nitrite (outlet nitrite), inlet nitrite nitrogen (inlet nitrate ammonia) and outlet nitrite nitrogen (outlet nitrate ammonia), and calculate the total nitrogen removal rate. The test results are as follows: Figure 2 shown.

[0053] The total nitrogen removal rate in the early stage is very unstable. There are two reasons for this. On the one hand, the short-term nitrification effect is not very stable at this time, and the concentration of nitrite nitrogen in the effluent fluctuates. On the other hand, there is a certain degree of denitrification in the reactor, so that there is still nitrite nitrogen in the effluent. Although pre-aeration was set up during the experiment to degrade most of the easily degradable organic matter, some of it may not be degraded. Due to the increase in the drainage ratio in this stage (more than 60%), the concentration of organic matter in the reactor increased, resulting in enhanced denitrification. This problem is easy to solve in actual operation. It is only necessary to ensure that the COD value of the effluent from the front-end biological pool is at a low level to reduce its impact on anaerobic ammonia oxidation. The most important factor affecting the treatment effect of the combined process is the short-term nitrification effect, which determines whether nitrite nitrogen can be obtained stably. The accumulation and consumption of nitrite nitrogen can be achieved through real-time monitoring of micro-dissolved oxygen. When the short-term nitrification operation effect in the early stage of stage two is unstable, the deviation of the ratio of ammonia nitrogen and nitrite nitrogen in the influent of the anaerobic ammonia oxidation reactor increases, which has a great impact on the total nitrogen removal rate. The total nitrogen removal rate is lower than 70% basically because the concentration of ammonia nitrogen or nitrite nitrogen in the influent is high, which makes the effluent concentration increase accordingly, so that the ratio of ammonia nitrogen to nitrite nitrogen in the influent can be controlled. When the nitrite nitrogen concentration of the mixed solution in the weak aeration aerobic zone increases to 20-40 mg / L, it is necessary to reduce the nitrite nitrogen concentration by regulating the dissolved oxygen concentration to increase the consumption of the substrate by the autotrophic denitrifying bacteria. When the nitrite nitrogen is insufficient, the air supply is increased to increase the nitrification rate of nitrifying bacteria and maintain the generation and consumption of nitrite nitrogen. In the actual operation process, the stable effect of the short-term nitrification in the front section is guaranteed, and the subsequent anaerobic ammonia oxidation system can control the ratio by adjusting the flow rate. The nitrite accumulation rate of the short-term nitrification in the later stage of this stage can be stabilized at more than 90%. At this time, the total nitrogen removal rate can be stabilized at a higher value, and the effluent can meet the standard, that is, the short-term nitrification-anaerobic ammonia oxidation combined process for treating wastewater can achieve the expected effect, which is feasible in actual engineering. Therefore, the biological denitrification reaction device of the utility model has a short startup time and a good denitrification effect.

[0054] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A biological denitrification reaction device, characterized in that: The invention comprises a pre-anaerobic zone, a weak aeration aerobic zone, a strong aeration aerobic zone and a sedimentation zone which are sequentially connected along the flow direction of mud and water; the sedimentation zone is provided with a sludge outlet and a drain outlet; the invention also comprises a reflow zone which is connected with the sludge outlet and connected with the pre-anaerobic zone for controlling the sludge concentration of the mixed liquid in the pre-anaerobic zone to be ≥6g / L; the reflow zone is connected with the weak aeration aerobic zone for controlling the sludge concentration of the mixed liquid in the weak aeration anaerobic zone to be ≥6g / L; the weak aeration aerobic zone is provided with a first aeration device and a first dissolved oxygen detection device for controlling the dissolved oxygen content in the weak aeration aerobic zone to be <0.5mg / L; the strong aeration aerobic zone is provided with a second aeration device for controlling the dissolved oxygen content in the strong aeration aerobic zone to be ≥1.0mg / L.

2. The biological denitrification reaction device according to claim 1, characterized in that: A first stirring device is provided in the weakly aerated aerobic zone.

3. The biological denitrification reaction device according to claim 1, characterized in that: A second pH detection device is also provided in the weakly aerated aerobic zone.

4. The biological denitrification reaction device according to claim 1, characterized in that: An anaerobic zone is also connected between the pre-anaerobic zone and the weakly aerated aerobic zone, and a first pH detection device and a first oxidation-reduction potential detection device are arranged in the anaerobic zone.

5. The biological denitrification reaction device according to claim 4, characterized in that: Anoxic zone I and anoxic zone II are also arranged between the anaerobic zone and the weakly aerated aerobic zone. The anaerobic zone, anoxic zone I, anoxic zone II and the weakly aerated aerobic zone are connected in sequence.

6. The biological denitrification reaction device according to claim 5, characterized in that: A second stirring device is provided in the anoxic zone I; and a third stirring device is provided in the anoxic zone II.

7. The biological denitrification reaction device according to claim 6, characterized in that: The anoxic zone II is provided with a second dissolved oxygen detection device and a second oxidation-reduction potential detection device.

8. The biological denitrification reaction device according to claim 7, characterized in that: The volume ratio of the anoxic zone I to the anoxic zone II is 5:8; the volume ratio of the weakly aerated aerobic zone to the strongly aerated aerobic zone is 4:

1.

9. The biological denitrification reaction device according to claim 5, characterized in that: A selection zone is also arranged between the anaerobic zone and the anoxic zone I, and the anaerobic zone, the selection zone and the anoxic zone I are connected in sequence.

10. The biological denitrification reaction device according to any one of claims 1 to 9, characterized in that: It also includes a stable sedimentation zone, which is arranged between the sedimentation zone and the strong aeration aerobic zone and is connected to the sedimentation zone and the strong aeration aerobic zone respectively.

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