A vertical flow enhanced biological denitrification device and wastewater treatment method

Abstract

This invention relates to a vertical flow enhanced biological denitrification device and wastewater treatment method. A denitrification agent dosing component is added at a suitable location on the outside of the externally inclined guide section of an existing vertical flow reactor. This component allows for the addition of corresponding enhanced denitrification agents at selected points, further strengthening the denitrification reaction, improving the selectivity of the functional microbial reaction, consuming the nitrates produced by the anaerobic ammonium oxidation reaction, and providing sufficient substrate for anaerobic ammonium oxidation. This significantly promotes the anaerobic ammonium oxidation reaction and further improves the total nitrogen removal rate. By achieving precise control of the dosing location and accurate dosing based on the reaction, the invention achieves a synergistic effect of minimizing agent dosage and maximizing denitrification efficiency while enhancing the autotrophic biological denitrification efficiency, ultimately achieving the goal of green, low-carbon, economical, and efficient denitrification of wastewater.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and particularly relates to a vertical flow enhanced biological denitrification device and wastewater treatment method. Background Technology

[0002] In the field of wastewater treatment, excessive discharge of nutrients such as nitrogen and phosphorus is a significant factor leading to eutrophication of water bodies, causing severe damage to the environmental ecosystem. Currently, most wastewater treatment plants still employ the traditional anaerobic-anoxic-oxic process. 2 The nitrogen removal process (NOx) involves nitrification and denitrification, which are the main metabolic processes in biological nitrogen removal. Nitrification includes two reactions: ammonia oxidation and nitrite oxidation. Ammonia oxidation refers to the oxidation of NH4+ by ammonia-oxidizing bacteria (AOB). + -N is converted into NO2 - The process of -N oxidation. Nitrite oxidation refers to the oxidation of ammonia to produce NO2. - -N is converted to NO3 by nitrite-oxidizing bacteria (NOB). - The process of reducing nitrogen (NO2) to nitrogen (N) involves denitrification. Denitrification refers to the process under anaerobic conditions where denitrifying bacteria (DNB) utilize organic carbon sources to convert the NO2 produced during nitrification into nitrogen. - -N or NO3 - The process of reducing nitrogen (N-) to nitrogen gas relies on high aeration costs and carbon source consumption to meet total nitrogen standards in effluent, which contradicts current energy conservation and emission reduction goals. Anammox, as an autotrophic nitrogen removal technology, is widely considered a promising option for upgrading and retrofitting wastewater treatment facilities. Anaerobic ammonia oxidation (Anammox) refers to the biological reaction process in which anaerobic ammonia-oxidizing bacteria (AnAOB) use ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor to convert ammonia nitrogen and nitrite nitrogen into nitrogen gas and nitrate nitrogen under anaerobic or anoxic conditions. Compared with the traditional nitrification-denitrification biological nitrogen removal process, anaerobic ammonia oxidation, as an autotrophic nitrogen removal process, has three significant advantages: 1) No carbon source needs to be added as an electron acceptor, saving nearly 100% of the carbon source required for denitrification; 2) Low oxygen consumption, saving energy and approximately 62.5% of oxygen demand; 3) Low sludge production, reducing the amount of residual sludge by 80% to 90%, resulting in lower sludge production and carbon source requirements.

[0003] However, Anammox inevitably produces nitrates (NH4+) during wastewater treatment. + +1.32NO2- →1.03N2+0.26NO3 - With increasingly stringent wastewater treatment standards, high nitrate accumulation can make it difficult to meet effluent total nitrogen requirements. However, these nitrates can be removed using denitrification. Current research has found that nitrates produced by Anammox can be removed through sulfur-driven autotrophic denitrification and a denitrification process achieved by precise addition of simple organic matter (such as sodium acetate). Furthermore, by controlling the reduction of nitrates to nitrites, more substrate can be provided for Anammox, thereby reducing effluent nitrate concentrations and meeting total nitrogen requirements. However, the current dosing methods are relatively crude and may not achieve optimal results.

[0004] Chinese patent application CN117069266A discloses a wastewater treatment device, including a device body with an internal reaction chamber, an inner cylinder, an aeration component, and a flow guiding component. While the reaction chamber incorporates selective activated sludge, the lack of enhanced denitrification agents results in poor reaction performance. Other existing technologies typically mix the agents directly with the reactants before the reaction begins, or add the agents directly from the inlet or top of the device when needed. Regardless of the dosing method, precise control over the dosing location is lacking, and precise dosing based on the current reaction progress is also impossible. Current autotrophic biological denitrification systems for wastewater suffer from a technical bottleneck: excessively high local nitrate nitrogen concentrations leading to excessive total nitrogen in the effluent. The core problem lies in the lack of precise control over areas with high nitrate nitrogen concentrations.

[0005] Therefore, how to develop a device with precise dosing capabilities, which can enhance the denitrification efficiency of autotrophic organisms while minimizing the dosage of chemicals and maximizing the denitrification efficiency, ultimately achieving the goal of green, low-carbon, economical, and efficient denitrification of wastewater, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To solve at least one of the above-mentioned technical problems, the present invention provides a vertical flow-enhanced biological denitrification device, comprising: an outer cylinder, an inner cylinder, a flow guiding assembly, a denitrification agent dosing assembly, and an aeration assembly; the inner cylinder is connected to the outer cylinder and divided into an inner reaction chamber located inside the inner cylinder and an outer reaction chamber located between the inner cylinder and the outer cylinder; the flow guiding assembly is connected to the axial bottom end of the inner cylinder and includes: an inner inclined flow guiding section, an outer inclined flow guiding section, a sieve hole disposed on the side wall of the inner inclined flow guiding section, and a through hole penetrating the flow guiding assembly; the denitrification agent dosing assembly includes a dosing unit disposed outside the outer inclined flow guiding section for targeted dosing of enhanced denitrification agent; the aeration assembly is disposed inside the outer inclined flow guiding section and aerates upwards;

[0007] The dosing unit includes: an inlet pipe, and a dosing valve, a dosing drive, and a dosing water tank arranged sequentially on the inlet pipe; the dosing drive is used to drive the dosing valve to open or close; one end of the inlet pipe is connected to the dosing water tank, and the other end is provided with an annular channel around the outer inclined guide section; multiple spaced distribution pipes are provided on the annular channel, and the ends of the distribution pipes are located in the middle of the outer side of the outer inclined guide section;

[0008] The flow guiding assembly further includes: a granular sludge retainer hinged to the outer wall of the outer inclined flow guide; the granular sludge retainer is capable of flipping upwards and includes several blades at the same height on the outer wall of the outer inclined flow guide; the several blades are spaced apart; and the outlet of the distribution pipe is located at the interval between pairs of blades.

[0009] Furthermore, the outlet of the distribution pipe on the outer inclined surface of the outer inclined guide section is misaligned with the screen holes on the inner inclined guide section.

[0010] Furthermore, an outlet is provided on the side of the outer cylinder corresponding to the bottom of the inner cylinder; the outlet of the distribution pipe is located below the outlet and away from the outlet.

[0011] Furthermore, a tapered expansion cavity is provided at the end of the distribution pipe.

[0012] Furthermore, the flow guiding assembly includes a first inner inclined flow guiding section, a first outer inclined flow guiding section, a second inner inclined flow guiding section, and a second outer inclined flow guiding section connected sequentially from top to bottom;

[0013] A first sieve hole is provided on the side wall of the first inclined guide section, and a second sieve hole is provided on the side wall of the second inclined guide section. The diameter of the second sieve hole is larger than that of the first sieve hole.

[0014] The aeration component is located at the second outer inclined guide section;

[0015] The denitrification agent dosing component is located on the outside of the second outer inclined guide section and is used to add enhanced denitrification agent.

[0016] Furthermore, the vertical flow enhanced biological denitrification device also includes: a flow propulsion assembly disposed in the first inner inclined flow guide section for upward flow propulsion, including: a flow propulsion base plate, a flow propulsion support, a flow propulsion main shaft, a flow propulsion impeller, and a flow propulsion drive component;

[0017] A flow-pushing base plate is located at the bottom end of the inner inclined flow guide section;

[0018] The jet propulsion bracket is mounted on the jet propulsion base plate;

[0019] The main propulsion shaft is located in the middle of the propulsion support;

[0020] The impeller blades and the drive components are nested outside the main shaft.

[0021] On the other hand, the present invention also provides a wastewater treatment method, employing any of the above-mentioned vertical flow enhanced biological denitrification devices, the steps of which include:

[0022] First, the wastewater enters the internal reaction chamber of the vertical flow enhanced biological denitrification device. Driven by the upward flow formed by the aeration components, it flows upward through the through holes to the aerobic reaction zone.

[0023] Next, the wastewater to be treated rises to the top edge of the inner cylinder and then flows around it, flowing downward into the outer reaction chamber and forming a downward flow. When the mixed liquid passes through the denitrification agent dosing component, the denitrification agent dosing component determines whether to add denitrification agent into the mixed liquid to promote enhanced biological denitrification treatment of large-diameter sludge particles.

[0024] Finally, some of the flocculent sludge and small-diameter granular sludge carried by the downstream flow re-enters the inner reaction chamber through the sieve holes on the side wall of the inner inclined guide section or by bypassing the lowest edge of the guide component, gradually growing into a mixed liquid of large-diameter granular sludge; some of the mixed liquid carrying large-diameter particles falls to the side wall of the outer inclined guide section, undergoes denitrification treatment with denitrification agents, and is circulated again through the through holes, while the clear liquid is discharged through the middle outlet.

[0025] Furthermore, the denitrification agent dosing assembly also includes: a sensor and a control unit;

[0026] The sensors include a nitrate nitrogen concentration monitor, a dissolved oxygen concentration monitor, a sludge thickness monitor, and a sludge concentration monitor, which are used to detect nitrate nitrogen concentration, dissolved oxygen concentration, sludge concentration, and sludge thickness, respectively.

[0027] The control unit is used to determine whether to add denitrification agents based on the nitrate concentration, and to determine the basic dosage based on the nitrate concentration; it also corrects the basic dosage based on the dissolved oxygen concentration, sludge concentration, and sludge thickness, and determines the final dosage.

[0028] Furthermore, nitrate concentration monitoring instruments are installed at the inlet, outlet, and denitrification zone;

[0029] The steps for determining whether to add a denitrification agent based on the nitrate nitrogen concentration, and for determining the basic dosage based on the nitrate nitrogen concentration, are as follows:

[0030] Determine whether the nitrate concentration in the denitrification zone exceeds the nitrate concentration threshold; if so, determine whether to add reagents.

[0031] The basic dosage is determined based on the difference between the influent nitrile nitrogen concentration and the effluent nitrile nitrogen concentration, as well as the difference between the nitrile nitrogen concentration in the denitrification zone and the nitrile nitrogen concentration threshold.

[0032] Furthermore, the steps for adjusting the baseline dosage based on dissolved oxygen concentration, sludge concentration, and sludge thickness to determine the final dosage are as follows:

[0033] Adjust the reagent utilization coefficient according to the dissolved oxygen concentration; if the dissolved oxygen concentration (DO) in the denitrification zone is >0.5 mg / L, increase the carbon source dosage; if the dissolved oxygen concentration (DO) in the denitrification zone is <0.2 mg / L, decrease the carbon source dosage.

[0034] Adjust the microbial carrying capacity coefficient according to the sludge concentration; if the sludge concentration MLSS < 2000 mg / L, add sludge first, then add carbon source; if MLSS > 4000 mg / L, reduce the amount of carbon source added.

[0035] Adjust the reactor's effective volume coefficient based on the sludge thickness; if the sludge thickness SV > 30%, increase the carbon source dosage; if SV < 15%, decrease the carbon source dosage.

[0036] Based on the agent utilization rate coefficient, the microbial community carrying capacity coefficient, and the effective volume coefficient of the reactor, the basic dosage is corrected to determine the final dosage.

[0037] This invention provides a vertical flow enhanced biological denitrification device and wastewater treatment method. Its core lies in adding a denitrification agent dosing component outside the inner inclined guide section, which further improves the denitrification effect. This is because: a large amount of anaerobic ammonia oxidation granular sludge accumulates outside the outer inclined guide section, where the dissolved oxygen level is very low, even in a completely anaerobic state; simultaneously, the anaerobic ammonia oxidation reaction is highly reactive, producing a large amount of nitrate, which needs to be further reduced to nitrogen gas. Biological denitrification requires the addition of electron donors or carbon sources. This invention, by precisely dosing enhanced denitrification agents at this location, can achieve precise control and multi-pathway denitrification, resulting in highly efficient and thorough denitrification. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort. In the drawings, the same parts use the same reference numerals. The drawings are not drawn to scale.

[0039] Figure 1 This is a schematic diagram of an embodiment of a vertical flow-enhanced biological denitrification device according to the present invention;

[0040] Figure 2 This is a partial schematic diagram of an embodiment of a denitrification agent dosing component of a vertical flow enhanced biological denitrification device according to the present invention;

[0041] Figure 3This is a schematic diagram of an embodiment of the feed pipe and conical expansion cavity of a vertical flow-enhanced biological denitrification device according to the present invention;

[0042] Figure 4 This is a schematic diagram of an embodiment of a vertical flow enhanced biological denitrification device propulsion assembly according to the present invention;

[0043] Figure 5 This is a schematic diagram of another embodiment of a vertical flow-enhanced biological denitrification device according to the present invention. Detailed Implementation

[0044] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is referred to as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0046] It should also be noted that if the embodiments of the present invention involve directional indications, such as up, down, left, right, front, back, etc., these directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly. Furthermore, if the embodiments of the present invention involve descriptions such as "first," "second," "S1," "S2," "step one," "step two," etc., these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance, or implicitly indicating the number of technical features indicated or the order of method execution. Those skilled in the art will understand that anything that does not violate the inventive concept and does not contradict the inventive points should be included within the scope of protection of the present invention.

[0047] This invention provides a vertical flow-enhanced biological nitrogen removal device, referenced Figure 1 It includes: outer cylinder 1, inner cylinder 2, flow guiding component 3, denitrification agent dosing component 4, and aeration component 5;

[0048] The inner cylinder is connected to the outer cylinder and is divided into an inner reaction chamber 21 located inside the inner cylinder and an outer reaction chamber 22 located between the inner cylinder and the outer cylinder.

[0049] The flow guiding assembly, connected to the axial bottom end of the inner cylinder, includes: an inner inclined flow guiding part 31, an outer inclined flow guiding part 32, a screen hole 33 provided on the side wall of the inner inclined flow guiding part, and a through hole 34 penetrating the flow guiding assembly;

[0050] The denitrification agent dosing assembly is located outside the outer inclined guide section and is used for targeted dosing of enhanced denitrification agents;

[0051] The aeration component is installed inside the outer inclined guide section and aerates upwards.

[0052] This embodiment presents the vertical flow enhanced biological denitrification device of the present invention. Its core feature is the addition of a denitrification agent dosing component outside the inclined guide section, which further improves the denitrification effect. This is because: a large amount of anaerobic ammonia oxidation granular sludge accumulates outside the inclined guide section, where the dissolved oxygen level is very low, even in a completely anaerobic state; simultaneously, the anaerobic ammonia oxidation reaction is highly reactive, producing a large amount of nitrate, which needs to be further reduced to nitrogen gas. Biological denitrification requires the addition of electron donors or carbon sources. The present invention, by precisely dosing enhanced denitrification agents at this location, can accurately control the reaction process and achieve multi-pathway denitrification, resulting in highly efficient and thorough denitrification.

[0053] Therefore, the key to this invention lies in adding a denitrification agent dosing component at a suitable location in the existing vertical flow reaction device, namely outside the outward-sloping guide section. This component allows for the addition of corresponding enhanced denitrification agents at selected points, further strengthening the denitrification reaction, improving the selectivity of the functional microbial reaction, consuming the nitrates produced by the anaerobic ammonium oxidation reaction, and providing sufficient substrate for anaerobic ammonium oxidation, thereby greatly promoting the anaerobic ammonium oxidation reaction and further improving the total nitrogen removal rate. By achieving precise control of the dosing location and accurately adding agents according to the reaction, the invention achieves a synergistic effect of minimizing agent dosage and maximizing denitrification efficiency while enhancing the denitrification efficiency of autotrophic organisms, ultimately achieving the goal of green, low-carbon, economical, and efficient denitrification of wastewater. The discovery and solution of this technical problem is a key technical concept of this invention.

[0054] Preferred, Reference Figure 1 and Figure 2 The denitrification agent dosing component 4 includes: a sensor 41, a control unit, and a dosing unit 42;

[0055] A sensor is used to monitor reaction indicators within the device; a control unit, connected at one end to the sensor and at the other end to the dosing unit, is used to issue a dosing signal based on the reaction indicators; the dosing unit, located outside the inclined guide section, is used to precisely add denitrifying agent to the outside of the inclined guide section based on the dosing signal. Preferably, the control unit is used to control the dosing valve and dosing drive on the dosing unit.

[0056] More preferably, the sensors include a nitrate nitrogen concentration monitor, a dissolved oxygen concentration monitor, a sludge thickness monitor, and a sludge concentration monitor, used to detect nitrate nitrogen concentration, dissolved oxygen concentration, sludge concentration, and sludge thickness, respectively.

[0057] The control unit is used to determine whether to add denitrification agents based on the nitrate concentration, and to determine the basic dosage based on the nitrate concentration when adding the agent; it also corrects the basic dosage based on the dissolved oxygen concentration, sludge concentration, and sludge thickness to determine the final dosage.

[0058] More preferably, in a preferred embodiment, the nitrate concentration monitor is installed at the inlet, outlet and denitrification zone;

[0059] Based on the nitrate concentration, it is determined whether to add denitrification agents. Specifically, it is determined whether the nitrate concentration in the denitrification zone exceeds the nitrate concentration threshold. If so, it is determined whether to add agents.

[0060] The basic dosage is determined based on the nitrate concentration. Specifically, the basic dosage is determined based on the difference between the influent nitrate concentration and the effluent nitrate concentration, as well as the difference between the nitrate concentration in the denitrification zone and the nitrate concentration threshold.

[0061] More preferably, the base dosage is adjusted based on the dissolved oxygen concentration, sludge concentration, and sludge thickness to determine the final dosage, specifically as follows:

[0062] The reagent utilization coefficient was adjusted based on the dissolved oxygen concentration (DO). ;

[0063] The microbial carrying capacity coefficient was adjusted based on the sludge concentration MLSS. ;

[0064] The effective volume coefficient of the reactor is adjusted based on the sludge thickness SV. ;

[0065] More preferably, the reagent utilization coefficient is adjusted based on the dissolved oxygen concentration (DO). Specifically: If the dissolved oxygen concentration (DO) in the denitrification zone is >0.5 mg / L (excessive aeration / DO leakage): the activity of denitrifying bacteria is inhibited, and the carbon source will be preferentially decomposed by aerobic bacteria. It is necessary to increase the amount of carbon source added (correction factor 1.2-1.5) and at the same time reduce the aeration intensity (such as adjusting the aeration valve and shortening the aeration time); If the dissolved oxygen concentration (DO) in the denitrification zone is <0.2 mg / L (anaerobic over-aeration): it may lead to anaerobic fermentation of sludge. It is necessary to reduce the amount of carbon source added (to avoid excessive carbon source accumulation leading to an increase in effluent COD) and at the same time perform slight aeration (micro-aeration to supplement oxygen and maintain sludge activity).

[0066] The microbial carrying capacity coefficient was adjusted based on the sludge concentration MLSS. Specifically: If MLSS < 2000 mg / L (insufficient microbial community): even with sufficient carbon source, the denitrification rate is still low (the microbial community cannot quickly consume nitrate nitrogen). In this case, sludge should be added first (such as sludge return or microbial inoculum addition), rather than blindly increasing the carbon source (otherwise, carbon source is wasted and effluent COD exceeds the standard); if MLSS > 4000 mg / L (excessive microbial community): DO mass transfer is difficult, DO is insufficient in some parts of the reactor, nitrification efficiency decreases → nitrate nitrogen production decreases, the amount of carbon source added needs to be reduced (correction coefficient 0.8-0.9), and sludge discharge should be carried out to reduce MLSS to a reasonable range.

[0067] The effective volume coefficient of the reactor is adjusted based on the sludge thickness SV. Specifically: If SV > 30% (sludge bulking / sedimentation difference): the actual effective volume V of the reactor is reduced (sludge occupies part of the space), the nitrate and nitrogen retention time is insufficient, and the amount of carbon source added needs to be increased (correction factor 1.1-1.2), while adding defoamer / flocculator (such as PAC) to improve sedimentation performance; If SV < 15% (sludge loss): MLSS is lost with the effluent, the total bacterial count decreases, and the amount of carbon source added needs to be reduced (to avoid the loss of unused carbon source), while checking the secondary sedimentation tank reflux ratio (increasing the reflux ratio to reduce sludge loss).

[0068] Example: Following a closed-loop joint control system of "monitoring → judgment → correction → feedback", the specific steps include:

[0069] Real-time online monitoring: Dissolved oxygen concentration (DO) (monitored separately in nitrification zone / denitrification zone), nitrate nitrogen concentration (influent / mid-stage reactor / effluent), sludge concentration (MLSS); Timed monitoring: Sludge thickness (SV), preferably every 4 hours.

[0070] Example of normal conditions: Influent nitrate nitrogen = 20 mg / L, target effluent nitrogen = 1 mg / L, reactor volume = 1000 m³ 3 MLSS=3000mg / L, DO=0.3mg / L in the denitrification zone, SV=25%.

[0071] Basic dosage of denitrifying agent (sodium acetate): 3.5 kg / mg × (20-1) mg / L × 1000 mg / L 3 =66.5kg;

[0072] Normal DO = 0.3 mg / L (meets requirements), no correction needed;

[0073] MLSS = 3000 mg / L (meets requirements), no correction needed;

[0074] SV=25% (meets requirements), no correction needed; → final dosage = 66.5kg.

[0075] Example of abnormal conditions: Influent nitrate nitrogen = 20 mg / L, DO in denitrification zone = 1.0 mg / L, MLSS = 4500 mg / L, SV = 35%.

[0076] Basic dosage = 66.5 kg;

[0077] DO too high (correction factor 1.3): 66.5 × 1.3 = 86.45 kg;

[0078] MLSS too high (correction factor 0.85): 86.45 × 0.85 ≈ 73.48 kg;

[0079] Excessive SV (correction factor 1.15): 73.48 × 1.15 ≈ 84.5 kg; → Final dosage ≈ 84.5 kg. At the same time, auxiliary measures such as reducing DO (reducing aeration), removing sludge (reducing MLSS), and adding PAC (to improve SV) need to be taken.

[0080] Preferably, after adjusting the dosage of the added chemicals, the effluent nitrate and nitrogen concentrations and parameter changes are continuously monitored:

[0081] If the effluent nitrate nitrogen exceeds the target value, it indicates insufficient reagent dosage. DO / MLSS / SV need to be checked again, and the correction factor adjusted (e.g., by increasing it by 0.1-0.2).

[0082] If the effluent nitrate nitrogen is less than the target value and COD increases (biological denitrification) / residual chlorine exceeds the standard (chemical denitrification): it indicates that the reagent dosage is too high and the correction factor needs to be reduced.

[0083] If the parameters do not change but the effluent nitrate nitrogen exceeds the standard, it may be due to insufficient sludge activity (such as nitrifying bacteria poisoning). It is necessary to test the sludge dehydrogenase activity rather than adding chemicals.

[0084] This embodiment presents a preferred embodiment of the nitrogen and phosphorus removal dosing component. Sensors monitor the nitrate concentration, dissolved oxygen concentration, sludge concentration, and sludge thickness in the reaction zone in real time. The control unit automatically starts and stops the dosing unit, enabling on-demand, targeted, and quantitative dosing of enhanced nitrogen removal agents, carbon sources, and other auxiliary agents. This helps maintain a suitable denitrification environment and improves the device's nitrogen removal efficiency. Simultaneously, because the dosing unit is located within the external inclined guide section, targeted dosing can be directly applied to the denitrification area without disrupting the stability of the granular sludge circulation flow field, reducing agent waste, lowering operating costs, and achieving energy-efficient and highly effective enhanced nitrogen removal. In the preferred embodiment, the nitrate concentration in the denitrification zone is first used to determine whether to add agents, providing precision and speed. Then, the basic dosing amount is determined based on the comprehensive nitrate concentrations in the three zones. Finally, the dosage is corrected based on the dissolved oxygen concentration, sludge concentration, and sludge thickness to determine the final dosing amount, further improving the nitrogen removal effect while minimizing agent waste.

[0085] It is worth noting that the key to this invention lies in the precise dosing of the denitrification agent at a specific location outside the inclined guide section. While the specific control strategy regarding the dosing method and dosage of the denitrification agent is preferred, it is not limited to this. Control can be achieved using a single indicator such as dissolved oxygen concentration or nitrate nitrogen concentration. For example, when dissolved oxygen is above 0.1 mg / L or nitrate nitrogen is above 5 mg / L, the control unit drives the dosing valve to open, increasing the dosage of the enhanced denitrification agent. Simultaneously, the dosing drive is controlled to increase the output power, thereby increasing the dosing speed. When dissolved oxygen is below 0.1 mg / L and nitrate nitrogen is below 5 mg / L, or when the local sludge thickness is above 0.5 m or the local sludge concentration is above 20,000 mg / L, the dosing unit is controlled to close. By combining manual online monitoring with automatic feedback control, on-demand dosing is achieved, avoiding over- or under-dosing, improving the utilization rate of the enhanced denitrification agent, and reducing operating costs. For example, regarding the dosage of the enhanced denitrification agent, for a small vertical flow enhanced biological denitrification device with an effective volume of 4.5L operating at an ammonia nitrogen concentration / influent nitrogen load of 250mg / L / 0.50kgNm⁻³d⁻¹, 3g of sodium acetate is added, and the aeration rate (AR) is adjusted to 1.3L / min. The agent control method involves dissolving 3g of sodium acetate in 100ml of water daily and adding it 12 times a day using the denitrification agent dosing component of this invention, with each addition being 7.2ml of sodium acetate solution for 2 minutes. This achieves targeted, timed, and quantitative enhanced denitrification agent dosing, further improving wastewater treatment efficiency.

[0086] More preferably, refer to Figure 1 and Figure 2 The dosing unit 42 includes: an inlet pipe 421, and a dosing valve 422, a dosing drive 423, and a dosing water tank 424 sequentially arranged on the inlet pipe 421;

[0087] Dosing actuator, used to drive the opening or closing of the dosing valve;

[0088] One end of the feed pipe is connected to the dosing water tank, and the other end is provided with an annular channel 425 around the outer inclined guide section;

[0089] The annular channel 425 is provided with multiple spaced distribution pipes 426, with the ends of the distribution pipes located in the middle of the outer side of the outer inclined guide section.

[0090] In this embodiment, the dosing inlet tank is used to buffer the enhanced denitrification agent. One end of the feed pipe is connected to the tank, serving as the agent delivery path between the dosing unit and the reaction zone. The other end has an annular channel surrounding the inclined guide section, which enables uniform circumferential dosing of the agent within the guide section. This avoids excessively high local concentrations that could impact the granular sludge, ensuring thorough mixing and diffusion of the enhanced denitrification agent during circulation, thereby improving denitrification efficiency and the denitrification reaction rate. Based on this, real-time monitoring data from the sensors is transmitted to the control unit, which in turn transmits it to the dosing drive. The dosing drive dynamically adjusts the flow rate of the enhanced denitrification agent in the feed pipe based on the real-time monitoring data from the dissolved oxygen sensor. Simultaneously, the control unit controls the opening and closing of the dosing valve, dynamically controlling the amount of enhanced denitrification agent added.

[0091] Preferred, Reference Figure 1 The outlet of the distribution pipe on the outer inclined surface of the outer inclined guide section is misaligned with the screen holes on the inner inclined guide section.

[0092] In this embodiment, the outlet of the feed pipe is further positioned in a staggered manner relative to the sieve holes on the side wall of the inner inclined guide section. This is not a conventional technical choice, but rather an adaptive change made based on the liquid flow and the denitrification requirements of different reaction processes. Since the sieve holes on the side wall of the inner inclined guide section are located at the top, and the outlet of the feed pipe is located at the bottom, this staggered arrangement is actually a uniform distribution and staggered spacing on the horizontal projection plane. This prevents the added enhanced denitrification agent from directly aligning with the upper sieve holes, causing the enhanced denitrification agent to diffuse directly into the inner reaction chamber along with the liquid flow through the sieve holes. This weakens the impact of the enhanced denitrification agent on the sieve hole area, allowing the enhanced denitrification agent to follow the second circulation trajectory of the aforementioned large-diameter particles, i.e., downward through the through-holes into the inner circulation to achieve directional flow, greatly enhancing the denitrification reaction.

[0093] More preferably, refer to Figure 1 The bottom of the inner cylinder is provided with a water outlet 6 on the side of the outer cylinder; the outlet of the material distribution pipe is located below the water outlet and away from the water outlet.

[0094] In this embodiment, the misalignment between the feed pipe outlet and the effluent outlet is not a conventional technical choice, but rather an adaptive change made based on the denitrification requirements of liquid flow and different reaction processes. Since the effluent outlet is used to discharge the treated clear liquid, positioning the feed pipe outlet below the effluent outlet avoids turbulence when the enhanced denitrification agent flows out, and also prevents the enhanced denitrification agent from diffusing to the effluent outlet, thus avoiding potential contamination of the effluent outlet and a reduction in wastewater treatment efficiency. More preferably, the effluent outlet is far from the screen openings to prevent the enhanced denitrification agent from mixing into the internal circulation through the screen openings, further improving the accuracy of the enhanced denitrification agent dosing position.

[0095] More preferably, refer to Figure 1The vertical flow enhanced biological denitrification device also includes a sludge discharge hole 8 located at the bottom of the outer cylinder 1. Large-diameter sludge particles are separated by gravity during wastewater circulation or when circulation stops.

[0096] More preferably, refer to Figure 1 The vertical flow enhanced biological denitrifier also includes: a granular sludge retainer 9 hinged to the outer wall of the outer inclined guide section; the granular sludge retainer 9 can be flipped upwards.

[0097] In this embodiment, a granular sludge retainer is added to the outer inclined guide section to prevent large-diameter granular sludge from sliding directly or flowing too quickly, thereby slowing down its flow velocity and increasing the residence time of large-diameter granular sludge on the outer wall of the outer inclined guide section. This ensures that the large-diameter granular sludge can fully undergo anaerobic ammonia oxidation and denitrification reactions, improving the nitrogen removal rate. Simultaneously, since the granular sludge retainer is hinged to the outer wall of the outer inclined guide section, it can freely rotate through the hinge point. The granular sludge retainer has the strongest blocking ability for large-diameter granular sludge when it is perpendicular to the outer wall of the outer inclined guide section; and the weakest blocking ability when it is parallel to the outer wall of the outer inclined guide section. By adjusting the rotation angle of the granular sludge retainer, the blocking ability for large-diameter granular sludge can be adjusted, thereby adjusting the residence time of large-diameter granular sludge on the outer wall of the outer inclined guide section to adapt to the reaction time of large-diameter granular sludge with different concentrations, further improving the adjustability of the device.

[0098] More preferably, the granular sludge retainer includes several blades at the same height on the outer side wall of the outer inclined guide section; the blades are spaced apart, and the outlet of the distribution pipe is located at the interval between pairs of blades.

[0099] In this embodiment, the granular sludge holding component includes several blades at the same height on the outer wall of the outwardly inclined guide section. The spaced-apart blades create a regular branching path for the wastewater flow. The outlet of the distribution pipe is located between pairs of blades, allowing the enhanced denitrification agent to diffuse freely to the vicinity of the large-diameter granular sludge through the outlet of the distribution pipe, resulting in better dosing. Simultaneously, it avoids the enhanced denitrification agent directly impacting the large-diameter granular sludge, preventing excessively high concentrations of the enhanced denitrification agent near the large-diameter granular sludge, which could lead to the death of functional microorganisms.

[0100] More preferably, refer to Figure 3 The end of the distribution pipe is provided with a tapered expansion cavity 427.

[0101] In this embodiment, a tapered expansion cavity is provided at the end of the distribution pipe. The tapered structure can effectively reduce the change in flow velocity, reduce the degree of fluid turbulence, and thus improve the stability of the flow rate.

[0102] Preferred, Reference Figure 5The number of inner inclined guide section 31 and outer inclined guide section 32 in the flow guiding component 3 are both two, including a first inner inclined guide section 31a, a first outer inclined guide section 32a, a second inner inclined guide section 31b and a second outer inclined guide section 32b connected from top to bottom;

[0103] A first sieve hole 33a is provided on the side wall of the first inwardly inclined flow guide section, and a second sieve hole 33b is provided on the side wall of the second inwardly inclined flow guide section. The diameter of the second sieve hole 33b is larger than that of the first sieve hole 33a.

[0104] Aeration component 5 is located at the second outer inclined guide section 32b;

[0105] The denitrification agent dosing component 4 is located on the outside of the second outer inclined guide section 32b and is used to add enhanced denitrification agent.

[0106] This embodiment presents a preferred embodiment of the flow guiding device, as well as the specific location settings of the aeration components and the denitrification agent dosing components. This is an improvement based on the adaptation to particle size, rather than a conventional technical selection. Because the particles at the larger second sieve openings have grown to medium to large sizes, targeted dosing at this location can further enhance the denitrification effect and improve the overall performance of wastewater treatment. Specifically: under the action of the upward flow, the clarified liquid, flocculent sludge, and small-diameter granular sludge in the wastewater are sequentially screened according to particle size along the inner reaction chamber and the outer reaction chamber between the inner and outer cylinders, and flow into the first and second sieve openings respectively. Because the first sieve aperture is above the second sieve aperture, and the aperture of the second sieve aperture is larger than that of the first sieve aperture, smaller granular sludge particles circulate through the inner reaction chamber, the outer reaction chamber between the inner and outer cylinders, and the first sieve aperture. Larger granular sludge particles circulate through the second sieve aperture. Due to the shorter circulation path, the smaller granular sludge particles can grow into larger granular sludge particles more quickly, and then continue to circulate through the second aperture, continuing to grow into large-diameter granular sludge particles, finally completing the second circulation trajectory. By setting the aperture sizes of the first and second sieve apertures, the first circulation trajectory is divided into a rapid growth path for smaller sludge particles and a deep circulation path for larger sludge particles, achieving graded control of the particle size gradient of granular sludge within the reactor. Specifically, the first screen, located above the second screen and with a smaller aperture, primarily targets the initially formed small-diameter granular sludge, focusing on promoting its rapid circulation and aggregation. The second screen, with its larger aperture, mainly filters medium to large-diameter granular sludge, allowing it to enter deeper circulation channels and further increase in size during long-path, long-duration flow, ultimately growing into stable, large-diameter granular sludge. This "small-to-large, graded progression" cyclical screening and growth mechanism not only increases the sludge granulation rate but also optimizes the particle size distribution of granular sludge within the reactor, facilitating the formation of a highly efficient and stable granular sludge system. This enhances the aerobic reaction of wastewater, improves the removal of organic pollutants, and further improves wastewater treatment efficiency and effluent quality. The first inner inclined guide section, the first outer inclined guide section, the second inner inclined guide section, the second outer inclined guide section, and the first and second screens effectively divide the entire reactor into two zones. The inner cylinder, the first inner inclined guide section, the first outer inclined guide section, the second inner inclined guide section, the first sieve hole, and the second sieve hole are mainly for the circulation of clear liquid, flocculent sludge, and small-diameter granular sludge, where aerobic reactions occur and organic matter is consumed. This part does not require an additional denitrification agent dosing component. The second outer inclined guide section, mainly between the guide section and the sidewall, is primarily for the anaerobic ammonia oxidation reaction of large-diameter granular sludge, removing ammonia nitrogen from the wastewater. Therefore, installing a denitrification agent dosing component at the second outer inclined guide section can further improve the nitrogen removal rate and enhance the wastewater treatment effect. The choice of this location is the result of the inventor's creative labor.

[0107] Preferred denitrification agents include sodium acetate, glucose, and reaction buffers.

[0108] In this embodiment, denitrifying microorganisms reduce nitrates at selected locations under anaerobic or anoxic conditions, enhancing the denitrification reaction. This allows nitrates to be reduced to nitrogen gas under the catalysis of a series of enzymes, ultimately releasing the nitrogen into the gaseous environment and reducing the nitrogen concentration in wastewater and large-particle sludge. Sodium acetate provides electron donors for the cell metabolism of denitrifying microorganisms, promoting nitrate reduction. Denitrifying microorganisms can also utilize sodium acetate, consuming it to enhance their activity and accelerate nitrate removal. Under anaerobic or anoxic conditions, they synergistically work with anaerobic ammonia-oxidizing microorganisms to enhance multi-pathway biological nitrogen removal, further improving nitrogen removal efficiency. Specifically, referring to Table 1, when the influent ammonia nitrogen concentration is 250 mg / L and the influent nitrogen load (NLR) is 0.5 kg Nm⁻³ d⁻¹, the addition of sodium acetate to the enhanced denitrification agent, under different aeration rates and organic matter dosages, achieves an ammonia nitrogen removal rate of 100% and a total nitrogen removal rate exceeding 80%. A reaction buffer is used to maintain the acid-base balance of the reaction system, prevent excessive pH changes, and further improve the stability of the reaction. Optional reaction buffers include sodium bicarbonate and / or soda ash. Specifically, the mass ratio of glucose to the effective component of the reaction buffer is greater than 0.1 but less than 50. The addition method is to prepare a mixed solution and inject it simultaneously, either continuously or intermittently, to enhance the multi-pathway biological denitrification reaction. More specifically, when the sludge has good granulation and a red color, and the anaerobic ammonia oxidation activity is greater than 0.4 gN / g-VSS / d, the enhanced denitrification agent is initiated; when the sludge has poor granulation, is not clearly red, and the anaerobic ammonia oxidation activity is less than 0.2 gN / g-VSS / d, the enhanced denitrification agent is discontinued.

[0109] Table 1. Effect of targeted application of sodium acetate on enhancing biological nitrogen removal.

[0110]

[0111] Specifically, the enhanced denitrification agent is introduced into the device in solution form by the denitrification agent dosing component. Dosing in solution form allows for rapid dispersion, further improving the reaction efficiency of the device and the accuracy of the enhanced denitrification agent dosing.

[0112] Preferably, the enhanced denitrification agent also includes one or more of acids, bases, calcium and magnesium compounds, and nutrients.

[0113] In this embodiment, denitrifying microorganisms can utilize nutrients to accelerate their growth and reproduction, and consume sodium acetate, thereby enhancing their activity and accelerating nitrate removal. The acid and alkali components are used to adjust the pH of the solution, control the pH of the reaction environment, optimize microbial growth and metabolism, and promote the smooth progress of the denitrification process. Calcium and magnesium compounds are used to soften the water, helping to precipitate some heavy metal ions in the water and preventing them from interfering with the denitrification process. Specifically, the dosage of the enhanced denitrification agent is 1 / 5 to 1 / 50 of the feed amount of the characteristic pollutant (ammonia nitrogen) to achieve a suitable ratio of agent dosage to characteristic pollutant feed amount, optimizing the reaction process.

[0114] More preferably, refer to Figure 1 and Figure 4 The vertical flow enhanced biological denitrification device further includes: a propulsion component 7 disposed in the inner inclined guide section, the propulsion component being used to propel the flow upward; preferably, the propulsion component is disposed in the first inner inclined guide section;

[0115] The propulsion assembly 7 includes: a propulsion base plate 71, a propulsion bracket 72, a propulsion main shaft 73, a propulsion impeller 74, and a propulsion drive component 75;

[0116] A flow-pushing base plate is located at the bottom end of the inner inclined flow guide section;

[0117] The jet propulsion bracket is mounted on the jet propulsion base plate;

[0118] The main propulsion shaft is located in the middle of the propulsion support;

[0119] The impeller blades and the drive components are nested outside the main shaft.

[0120] In this embodiment, a propulsion assembly is added inside the inclined guide section of the vertical flow enhanced biological denitrification device. The aeration assembly and the propulsion assembly work together to propel the flow upwards, accelerating the upward flow along the bottom of the guide assembly, the through hole, and the inclined guide section, forming a stable segmented flow structure and optimizing the hydrodynamic performance of the liquid flow. In the propulsion assembly, the propulsion support and the propulsion base plate mainly serve a supporting role. The propulsion drive component drives the propulsion main shaft to rotate, which in turn drives the blades nested on the propulsion main shaft to rotate. The propulsion impeller blades rotate continuously and propel the flow upwards, accelerating the upward flow velocity of the sewage. In the sewage granular sludge system, the particulate matter carried in the sewage fluid will rise rapidly along the direction of fluid movement, exhibiting turbulent flow, and will be uniformly mixed with the enhanced denitrification agent, further improving the sewage circulation efficiency.

[0121] On the other hand, the present invention also provides a wastewater treatment method, employing any of the above-mentioned vertical flow enhanced biological denitrification devices, the steps of which include:

[0122] First, the wastewater can be pretreated by the influent pretreatment unit and then enter the internal reaction chamber of the vertical flow enhanced biological denitrification device. Under the upward flow generated by the aeration components, it flows upward through the through holes to the aerobic reaction zone.

[0123] Next, the wastewater to be treated rises to the top edge of the inner cylinder and then flows around it, flowing downward into the outer reaction chamber and forming a downward flow. When the mixed liquid passes through the denitrification agent dosing component, the denitrification agent dosing component determines whether to add denitrification agent into the mixed liquid to promote enhanced biological denitrification treatment of large-diameter sludge particles.

[0124] Finally, some of the flocculent sludge and small-diameter granular sludge carried by the downstream flow re-enters the inner reaction chamber through the sieve holes on the side wall of the inner inclined guide section or by bypassing the lowest edge of the guide component, gradually growing into a mixed liquid of large-diameter granular sludge; some of the mixed liquid carrying large-diameter particles bypasses the side wall of the outer inclined guide section, undergoes denitrification treatment by denitrification agents, and is circulated again through the through holes, while the clear liquid is discharged through the middle outlet.

[0125] This embodiment presents a wastewater treatment method using any of the aforementioned vertical flow enhanced biological denitrification devices. The wastewater undergoes pretreatment, such as filtration and sedimentation, to remove various impurities. Within the inner reaction chamber, the wastewater is driven by an upward flow generated by the aeration components, resulting in separate circulation paths for flocculent sludge and small-diameter granular sludge. This achieves rapid circulation of small-diameter sludge within the inner reaction chamber and sidewall sieve openings, while large-diameter sludge undergoes deep circulation within the outer reaction chamber and through-holes. Simultaneously, the addition of chemicals is controlled separately from the sludge particle size growth path, achieving a coupled treatment effect of "enhanced aerobic treatment + localized denitrification," resulting in more stable effluent quality and a higher denitrification rate. More preferably, the dissolved oxygen condition in the aerobic reaction zone is 0.1-0.2 mg / L, and the dissolved oxygen condition in the hypoxic zone is <0.1 mg / L, to achieve the desired wastewater denitrification effect.

[0126] The above-described wastewater treatment method is based on the invention of the vertical flow enhanced biological denitrification device, and its technical effects and features are combined in detail here. The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A vertical flow-enhanced biological nitrogen removal device, characterized in that, include: Outer cylinder, inner cylinder, flow guiding components, denitrification agent dosing components, and aeration components; The inner cylinder is connected to the outer cylinder, and is divided into an inner reaction chamber located inside the inner cylinder and an outer reaction chamber located between the inner cylinder and the outer cylinder; the flow guiding assembly is connected to the axial bottom end of the inner cylinder and includes: an inner inclined flow guiding part, an outer inclined flow guiding part, a sieve hole provided on the side wall of the inner inclined flow guiding part, and a through hole penetrating the flow guiding assembly; the denitrification agent dosing assembly includes a dosing unit provided on the outside of the outer inclined flow guiding part for targeted dosing of enhanced denitrification agent; the aeration assembly is provided inside the outer inclined flow guiding part for upward aeration; The dosing unit includes: an inlet pipe, and a dosing valve, a dosing drive, and a dosing water tank arranged sequentially on the inlet pipe; the dosing drive is used to drive the dosing valve to open or close; one end of the inlet pipe is connected to the dosing water tank, and the other end is provided with an annular channel around the outer inclined guide section; multiple spaced distribution pipes are provided on the annular channel, and the ends of the distribution pipes are located in the middle of the outer side of the outer inclined guide section; The flow guiding assembly further includes: a granular sludge retainer hinged to the outer wall of the outer inclined flow guide; the granular sludge retainer is capable of flipping upwards and includes several blades at the same height on the outer wall of the outer inclined flow guide; the several blades are spaced apart; and the outlet of the distribution pipe is located at the interval between pairs of blades.

2. The vertical flow-enhanced biological nitrogen removal device according to claim 1, characterized in that, The outlet of the distribution pipe on the outer inclined surface of the outer inclined guide section is misaligned with the screen holes on the inner inclined guide section.

3. The vertical flow-enhanced biological denitrification device according to claim 2, characterized in that, The bottom of the inner cylinder is located on the side of the outer cylinder, where the water outlet is located; the outlet of the distribution pipe is located below the water outlet and away from the water outlet.

4. The vertical flow-enhanced biological nitrogen removal device according to claim 3, characterized in that, A tapered expansion cavity is provided at the end of the feed pipe.

5. The vertical flow-enhanced biological nitrogen removal device according to any one of claims 1 to 4, characterized in that, The flow guiding assembly includes a first inner inclined flow guiding section, a first outer inclined flow guiding section, a second inner inclined flow guiding section, and a second outer inclined flow guiding section connected sequentially from top to bottom; A first sieve hole is provided on the side wall of the first inclined guide section, and a second sieve hole is provided on the side wall of the second inclined guide section. The diameter of the second sieve hole is larger than that of the first sieve hole. The aeration component is located at the second outer inclined guide section; The denitrification agent dosing component is located on the outside of the second outer inclined guide section and is used to add enhanced denitrification agent.

6. The vertical flow-enhanced biological nitrogen removal device according to claim 5, characterized in that, Also includes: The propulsion assembly, which is installed in the first inner inclined guide section, is used to propel the flow upward and includes: a propulsion base plate, a propulsion bracket, a propulsion main shaft, a propulsion impeller, and a propulsion drive component; A flow-pushing base plate is located at the bottom end of the inner inclined flow guide section; The jet propulsion bracket is mounted on the jet propulsion base plate; The main propulsion shaft is located in the middle of the propulsion support; The impeller blades and the drive components are nested outside the main shaft.

7. A wastewater treatment method, employing the vertical flow enhanced biological denitrification device as described in any one of claims 1 to 6, characterized in that the step include: First, the wastewater enters the internal reaction chamber of the vertical flow enhanced biological denitrification device. Driven by the upward flow formed by the aeration components, it flows upward through the through holes to the aerobic reaction zone. Next, the wastewater to be treated rises to the top edge of the inner cylinder and then flows around it, flowing downward into the outer reaction chamber and forming a downward flow. When the mixed liquid passes through the denitrification agent dosing component, the denitrification agent dosing component determines whether to add denitrification agent into the mixed liquid to promote enhanced biological denitrification treatment of large-diameter sludge particles. Finally, some of the flocculent sludge and small-diameter granular sludge carried by the downstream flow re-enters the inner reaction chamber through the sieve holes on the side wall of the inner inclined guide section or by bypassing the lowest edge of the guide component, gradually growing into a mixed liquid of large-diameter granular sludge; some of the mixed liquid carrying large-diameter particles falls to the side wall of the outer inclined guide section, undergoes denitrification treatment with denitrification agents, and is circulated again through the through holes, while the clear liquid is discharged through the middle outlet.

8. The wastewater treatment method according to claim 7, characterized in that, The nitrogen removal agent dosing assembly also includes: sensors and a control unit; The sensors include a nitrate nitrogen concentration monitor, a dissolved oxygen concentration monitor, a sludge thickness monitor, and a sludge concentration monitor, which are used to detect nitrate nitrogen concentration, dissolved oxygen concentration, sludge concentration, and sludge thickness, respectively. The control unit is used to determine whether to add denitrification agents based on the nitrate concentration, and to determine the basic dosage based on the nitrate concentration; it also corrects the basic dosage based on the dissolved oxygen concentration, sludge concentration, and sludge thickness to determine the final dosage.

9. The wastewater treatment method according to claim 8, characterized in that, Nitrate concentration monitors are installed at the inlet, outlet, and denitrification zone; The steps for determining whether to add a denitrification agent based on the nitrate nitrogen concentration, and for determining the basic dosage based on the nitrate nitrogen concentration, are as follows: Determine whether the nitrate concentration in the denitrification zone exceeds the nitrate concentration threshold; if so, determine whether to add reagents. The basic dosage is determined based on the difference between the influent nitrile nitrogen concentration and the effluent nitrile nitrogen concentration, as well as the difference between the nitrile nitrogen concentration in the denitrification zone and the nitrile nitrogen concentration threshold.

10. The wastewater treatment method according to claim 9, characterized in that, The steps for adjusting the baseline dosage and determining the final dosage based on dissolved oxygen concentration, sludge concentration, and sludge thickness are as follows: Adjust the reagent utilization coefficient according to the dissolved oxygen concentration; if the dissolved oxygen concentration (DO) in the denitrification zone is >0.5 mg / L, increase the carbon source dosage; if the dissolved oxygen concentration (DO) in the denitrification zone is <0.2 mg / L, decrease the carbon source dosage. Adjust the microbial carrying capacity coefficient according to the sludge concentration; if the sludge concentration MLSS < 2000 mg / L, add sludge first, then add carbon source; if MLSS > 4000 mg / L, reduce the amount of carbon source added. Adjust the reactor's effective volume coefficient according to the sludge thickness; if the sludge thickness SV > 30%, increase the amount of carbon source added. If SV < 15%, reduce the amount of carbon source added; Based on the agent utilization rate coefficient, the microbial community carrying capacity coefficient, and the effective volume coefficient of the reactor, the basic dosage is corrected to determine the final dosage.

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