A sequencing batch reactor and wastewater treatment method with staged influent for enhanced denitrification

Abstract

This application discloses a sequencing batch reactor (SBR) for enhanced denitrification using a staged influent process and a wastewater treatment method. The enhanced denitrification SBR is a multi-compartment structure operating in parallel. A network-like, multi-point upward-flow uniform water distribution system includes an influent channel along the top of the tank, an influent shaft connected to it, a bottom distribution channel connected to the influent shaft, and multiple distribution pipes connected to the bottom distribution channel. The distribution pipes have a gap with the tank bottom, and the bottom outlet openings face the tank bottom. An electric gate is installed at the connection between the influent shaft and the influent channel. The network-like, multi-point uniform dosing system includes a main pipe arranged along the top of the tank and multiple dosing branch pipes connected to it. Electric valves are installed at the branches of the main pipe. The dosing branch pipes have downward-facing dosing ports at intervals. This enhanced denitrification SBR uses a staged influent process to treat wastewater, maximizing the utilization of carbon sources. The water in the tank is uniformly mixed, avoiding reagent waste, and can rely on initial drainage to reduce total water loss.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and in particular to a sequencing batch reactor with enhanced denitrification using staged influent and a wastewater treatment method. Background Technology

[0002] In traditional plug-flow biological reactors, the denitrification effect is closely related to the nitrification liquor recirculation ratio; a higher recirculation ratio can improve the denitrification effect. Sequencing batch biological reactors, on the other hand, are spatially undivided, with each reaction stage completed within the same tank, eliminating the need for nitrification liquor recirculation. Theoretically, this is the most ideal denitrification process. However, the inventors of this application have discovered in practice that conventional sequencing batch reactors suffer from difficulties in achieving complete mixing of the water within the tank, hindering further improvements in treatment efficiency.

[0003] Furthermore, in recent years, as the effects of improving the quality and efficiency of sewage pipe networks have gradually become apparent, the influent characteristics of some domestic sewage treatment plants have shifted to lower C / N ratios or higher N concentrations. Therefore, the effectiveness of biological denitrification has become a major challenge in biological treatment. Blindly adding large amounts of external carbon sources to reduce the total nitrogen concentration in the effluent will significantly increase the operating costs of sewage treatment plants. Thus, solving these problems has become a difficult issue in current biological treatment. The sequencing batch reactor (SBR) process, used in existing technologies, is an activated sludge sewage treatment technology that operates on an intermittent aeration basis. Its main characteristic is its ordered and intermittent operation. The core of SBR technology is the SBR reactor, which integrates equalization, primary sedimentation, biodegradation, and secondary sedimentation functions into one tank, eliminating the need for digestate return and sludge return systems.

[0004] However, the inventors recognized that there were problems such as the inability to achieve complete mixing of the water in the tank, which would affect the treatment effect. The sequencing batch reactor is a large tank, and water is generally introduced from one side of the tank wall. The lateral flow of the water in the tank mainly relies on the high-level water level overflow and the propulsion of the submersible agitator. It is difficult for the water to achieve uniform mixing with the remaining water in the tank. Therefore, the C / N ratio is not consistent in different parts of the tank, thus affecting the treatment effect.

[0005] Furthermore, the inventors also noted the problem of waste caused by excessive dosage. In sequencing batch reactors, chemicals are typically added along the sidewalls, resulting in poor mixing uniformity. During on-site operation, to achieve the desired treatment effect, the actual dosage often far exceeds the theoretically required dosage, leading to unnecessary waste.

[0006] Furthermore, the inventors discovered that using a decanter for drainage in sequencing batch reactors (SBRs) results in significant overall water loss. SBRs typically use decanters for drainage, leading to a substantial difference in water level before and after drainage. Because the water level drops after sedimentation in the SBR, and downstream structures must be designed based on the minimum influent level, this inherently increases the overall water loss of the SBR. Summary of the Invention

[0007] Based on the above findings, according to one embodiment of this application, the purpose is to provide a sequencing batch reactor and wastewater treatment method for enhanced denitrification, which solves at least one problem existing in the current biological treatment process by improving the treatment effect of the biological treatment tank itself.

[0008] The above objective can be achieved through the following technical solutions:

[0009] According to one aspect of this application, this application provides a sequencing batch reactor (SBR) for enhanced denitrification using staged water inlet. The SBR includes a water distribution system, a stirring device, an aeration device, a drainage device, and an external carbon source addition system. The SBR with staged water inlet is a multi-compartment structure operating in parallel.

[0010] The water distribution system adopts a mesh-like, multi-point, upward-flowing, uniform water distribution system for multi-stage water intake. It includes: an intake channel along the top of the reaction tank; intake shafts connected to the intake channel in each compartment; bottom distribution channels connected to the intake shafts along the bottom of each compartment; and multiple distribution pipes located in each compartment and connected to the bottom distribution channels. The multiple distribution pipes in each compartment are horizontally spaced and have a gap with the bottom of the tank. The bottom of each distribution pipe has an outlet opening facing the bottom of the tank to create a turbulent laminar flow during water intake. An electric gate is installed at the connection between the intake shaft and the intake channel.

[0011] The external carbon source dosing system is a mesh-like multi-point uniform dosing system. The carbon source dosing pipeline is set along the top of the pool and includes: a main pipe arranged along the walkway plate on the top of the pool and multiple dosing branch pipes set on the top of each cell and connected to the main pipe. An electric valve is installed at the branch where the main pipe connects to the dosing branch pipes. The multiple dosing branch pipes on the top of each cell form a ring, and each dosing branch pipe is provided with a downward-opening dosing port at intervals.

[0012] Optionally, the water inlet channel, water inlet shaft, bottom distribution channel and pool body are an integrated structure made of reinforced concrete.

[0013] Optionally, the bottom water distribution channel is set along the middle of the grid pool, and multiple water distribution pipes are evenly distributed on both sides of the bottom water distribution channel. The bottom water distribution channel is perpendicular to the water inlet shaft, and the projection of the bottom water distribution channel is perpendicular to the water inlet channel.

[0014] Optionally, the gap between the water distribution pipe and the bottom of the pool is 40-60mm, and the distance between two adjacent water distribution pipes is 450-550mm. Optionally, the cross-sectional shape of the water distribution pipe is semi-circular, triangular, or rectangular. Optionally, the water distribution pipe is made of stainless steel.

[0015] Optionally, two rows of water outlet holes are arranged at the bottom of each water distribution pipe. Optionally, the two rows of water outlet holes are spaced 55-65mm apart. Optionally, the diameter of the water outlet holes is 25-35mm.

[0016] Optionally, the dosing branch pipes at the top of each tank are spaced 3m to 5m apart. Optionally, a dosing port is provided on each dosing branch pipe at 3m to 5m intervals.

[0017] Optionally, it also includes a control system, which is connected to the water distribution system, the stirring device, the aeration device, the drainage device, and the external carbon source addition system.

[0018] Optionally, the control system needs to be interlocked with the level gauge in the pool.

[0019] According to another aspect of this application, this application provides a wastewater treatment method using multi-stage influent, which uses a sequencing batch reactor with enhanced denitrification and staged influent as described in this application for wastewater treatment, and the wastewater treatment process employs multi-stage influent.

[0020] Optionally, at least one stage of the multi-stage influent process involves initial drainage occurring simultaneously with the water level rise in the influent booster tank, after the turbulent laminar flow is formed by the influent entering through a mesh-like multi-point upward uniform water distribution system, and based on the isolation effect of the sludge layer.

[0021] Optionally, it includes at least: two-stage water intake and one-stage addition of an external carbon source; wherein, the first-stage water intake consumes the residual nitrate nitrogen in the pool, and then aeration is performed to generate new nitrate nitrogen; the second-stage water intake consumes the nitrate nitrogen generated in the previous stage water intake until the carbon source in the raw water is exhausted, and then aeration is performed to generate new nitrate nitrogen; after the two-stage water intake, an external carbon source is added to reduce the nitrate nitrogen concentration in the water to the set value of the effluent, and aeration ensures that the carbon concentration in the effluent meets the standard.

[0022] Optionally, the process includes the following steps: 1) Performing a first-stage water intake while simultaneously draining water initially; draining water using a drainage device after the water intake stops; performing a first-stage anoxic reaction by stirring; performing a first-stage aerobic reaction by aeration; 2) Performing a second-stage water intake; performing a second-stage anoxic reaction by stirring; performing a second-stage aerobic reaction by aeration; 3) Performing a third-stage anoxic reaction by stirring and adding an external carbon source; performing a third-stage aerobic reaction by aeration; settling; draining water and removing sludge, then leaving the system idle.

[0023] Beneficial effects: According to one embodiment of this application, by adopting a mesh-like multi-point upward flow uniform water distribution system and a mesh-like multi-point uniform dosing system to form an enhanced denitrification sequencing batch reactor, and by adopting staged water intake, the overall denitrification effect of the reactor can be improved, the utilization rate of raw water carbon source can be increased, the amount of external carbon source added can be reduced, and the overall water loss of the reactor can be reduced.

[0024] Compared with the prior art, this application also has the following advantages:

[0025] 1) By adopting a multi-point upward flow uniform water distribution system with a mesh at the bottom of the pool, the uniformity of the mixing between the incoming water and the water in the pool is improved compared with the conventional one-sided water inlet technology.

[0026] 2) By arranging a mesh-like multi-point uniform external carbon source dosing port on the top of the pool, the agent is evenly distributed into the water body, thereby improving the uniformity of the agent and water mixing, maximizing the utilization of the external carbon source, overcoming the problem of increased dosage caused by dosing on one side, reducing the agent dosing cost, and reducing the operating cost of the sewage treatment plant.

[0027] 3) Based on the mesh-like multi-point upward flow uniform water distribution system of this application, the staged water intake method can maximize the utilization of carbon sources in the raw water.

[0028] 4) After sedimentation, a small-disturbance laminar flow is formed by the upward flow uniform water distribution system at multiple points on the bottom of the tank. Then, the sludge layer is used for isolation, so that the water inlet raises the water level in the tank without disturbing the upper layer of treated water. In this way, the initial drainage can be carried out by raising the water level by the inlet without using a decanter, thereby reducing the overall water loss of the reaction tank. Attached Figure Description

[0029] Figure 1 This is a plan view of the four-cell SBR tank water distribution system in one embodiment of this application;

[0030] Figure 2 yes Figure 1 AA cross-section view;

[0031] Figure 3 yes Figure 1 BB cross-section;

[0032] Figure 4 This is a plan view of the external carbon source addition system of a four-cell SBR tank in one embodiment of this application;

[0033] Figure 5 This is a schematic diagram of the underlying water distribution pipe structure in an embodiment of this application;

[0034] Figure 6 This is a schematic diagram of the wastewater treatment process in one embodiment of this application. Detailed Implementation

[0035] The technical solutions of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0036] This application provides a sequencing batch reactor (SBR) for enhanced denitrification using a staged influent method. The SBR includes a water distribution system, a stirring device, an aeration device, a drainage device, and an external carbon source dosing system. The water distribution system is a mesh-like, multi-point, upward-flowing, uniform water distribution system, and the external carbon source dosing system is a mesh-like, multi-point, uniform dosing system. This enhanced denitrification SBR, based on a multi-stage influent method, improves the overall denitrification effect of the reactor, increases the utilization rate of the raw water carbon source, reduces the amount of external carbon source added, and reduces the overall water loss of the reactor.

[0037] Figures 1 to 5 The schematic diagram illustrates the structure of a sequencing batch reactor (SBR) for enhanced nitrogen removal in one embodiment of this application. This embodiment is a four-cell SBR. See below for reference. Figures 1 to 5 This application will provide a further, more detailed explanation of the sequencing batch reactor for enhanced denitrification using a staged water intake.

[0038] This application adopts a mesh-like multi-point upward flow (flow from bottom to top) uniform water distribution system, which can make the multi-stage water intake and the original pool water mix more evenly and improve the uniformity of water distribution.

[0039] The sequencing batch reactor (SBR) has an inlet channel at its top to supply water to the multiple SBR cells operating in parallel. Each SBR cell has an inlet shaft connected to the inlet channel, and an electrically operated gate is installed at the connection between the inlet shaft and the inlet channel to control the water intake and flow rate. Figure 1 and Figure 3 As shown in this embodiment of the four-compartment SBR tank water distribution system, an inlet channel is provided along the middle of the top of the overall reaction tank (top of the middle tank wall). Figure 2 In this embodiment, the water inlet shafts are located in the middle of each SBR tank, close to the tank wall and the water inlet channel. Water is supplied to the four SBR tanks respectively under the control of the electric gates at the four water inlet shafts and their inlets.

[0040] In each SBR tank, a bottom distribution channel connected to the inlet shaft is installed along the bottom of the tank. Each bottom distribution channel is connected to multiple distribution pipes. Wastewater enters the bottom distribution channel in each SBR tank through the inlet shaft, and then enters the SBR tank through the bottom distribution pipes. Figure 1As shown in the embodiment of the four-compartment SBR pool water distribution system, the bottom water distribution channel is set along the middle of the pool, and multiple water distribution pipes are evenly distributed on both sides of the bottom water distribution channel. The bottom water distribution channel is perpendicular to the water inlet shaft, and the projection of the bottom water distribution channel is perpendicular to the water inlet channel, which can further improve the uniformity of water distribution.

[0041] Furthermore, in this application, the inlet channel, inlet shaft, and bottom distribution channel can be made of reinforced concrete. Further, the inlet channel, inlet shaft, and bottom distribution channel can be cast simultaneously with the pool body to form an integrated structure.

[0042] The water distribution pipe has a gap with the bottom of the pool. The bottom of the water distribution pipe has outlet holes facing the bottom of the pool, creating a network of multiple points where water flows upwards evenly, forming a turbulent laminar flow. This laminar flow pattern can eliminate the disruption of sludge settling caused by large water flows impacting the sludge layer at the openings; simultaneously, the sludge layer can be used to reduce the impact on the effluent quality. Further, the gap between the water distribution pipe and the bottom of the pool is 40-60 mm, and the distance between two adjacent water distribution pipes is 450-550 mm. Figure 3 As shown in this embodiment, the bottom of the water distribution pipe is 50mm from the bottom of the pool, and a water distribution pipe is arranged every 500mm.

[0043] The water distribution pipes at the bottom of each SBR tank can be made of stainless steel, and the cross-sectional shape can be semi-circular, triangular, or rectangular, among other shapes. For example... Figure 5 As shown in the specific embodiment, it can be A semi-circular water distribution pipe; it can be an isosceles triangular water distribution pipe with a base of 100mm and a height of 50mm; it can also be a rectangular water distribution pipe with a length of 100mm and a width of 50mm.

[0044] Preferably, two rows of water outlet holes are arranged at the bottom of each water distribution pipe, which can improve the uniformity of water output, reduce the impact of water flow, and promote regular laminar flow. Further, considering the size and structural strength of the water distribution pipe, the interval between the two rows of water outlet holes is controlled at 55-65 mm. Based on the above hole spacing and the size and structural strength of the water distribution pipe, the diameter of the water outlet holes is set to 25-35 mm. Figure 5 As shown in the specific embodiment, two rows of pipes are evenly arranged at 60mm intervals at the bottom. The water outlet tunnel forms a network-like, multi-point upward-flowing, uniformly distributed water distribution system.

[0045] This application adopts a mesh-like multi-point uniform dosing system to uniformly add external carbon sources, which can improve the uniformity of dosing, make the agent mix more evenly with the water, facilitate the maximum utilization of external carbon sources, reduce the cost of agent addition, and reduce the operating cost of wastewater treatment plants.

[0046] In this system, a carbon source dosing pipeline is installed at the top of the sequencing batch reactor (SBR). The main pipeline runs along the walkway at the top of the reactor, and branch pipelines for chemical dosing are installed at the top of each SBR cell. These branch pipelines are connected to the main pipeline, and electric valves are installed at the branch points to control the dosing time and dosage. Each branch pipeline has a downward-opening dosing port at intervals. Furthermore, forming a ring shape among the multiple branch pipelines at the top of each cell further improves the uniformity of chemical dosing. Figure 4 As shown in the embodiment of the four-compartment SBR tank water distribution system, the main pipe is located at the top of the middle tank wall, and three dosing branch pipes are spaced apart and connected at their ends to form a ring.

[0047] Furthermore, a DN20-DN30 carbon source dosing branch pipe (i.e., a dosing branch pipe) is installed at 3m-5m intervals on the top of each SBR tank, forming a ring. A DN20 dosing port is installed downwards at 3m-5m intervals on each dosing branch pipe, forming a network-like multi-point uniform dosing system.

[0048] In addition, this application adopts a sequencing batch reactor for enhanced denitrification with staged water intake, and also includes a control system. The control system is connected to the water distribution system, stirring device, aeration device, drainage device and external carbon source addition system, and is used to control the multi-stage water intake, stirring, aeration, drainage and addition of external carbon sources during wastewater treatment. The control system needs to be interlocked with the liquid level gauge in the tank for online or remote control.

[0049] Figure 6 The diagram illustrates the principle of a wastewater treatment process using a staged influent in a sequencing batch reactor for enhanced denitrification according to this application, and also illustrates the treatment flow.

[0050] As described above, conventional sequencing batch reactors use a method of water intake from one side of the tank wall, which makes it difficult for the intake water to achieve uniform mixing with the remaining water in the tank, and the C / N ratio is not consistent throughout the tank. In addition, the inventors of this application also recognize that, based on the conventional water intake method, if a staged water intake is adopted to maximize the utilization of carbon sources in the raw water, the mixing effect of a plug flow reactor cannot be achieved due to the poor water intake location and the poor water flow in the tank, which in turn leads to low utilization of carbon sources in the raw water and low denitrification rate.

[0051] In this application, based on the enhanced denitrification sequencing batch reactor, the wastewater treatment process using a staged influent can improve the utilization rate of raw water carbon sources and increase the denitrification rate.

[0052] The wastewater treatment targets in this application are domestic sewage with low C / N ratios or high N concentrations. Examples include municipal sewage from southwestern regions or municipal sewage mixed with industrial wastewater. Biological phosphorus removal is not considered because the cost of biological phosphorus removal is far higher than that of chemical phosphorus removal when the influent carbon source is insufficient.

[0053] Furthermore, in the multi-stage influent process of this application, at least one stage of influent involves initial drainage simultaneously with the water level rise in the influent tank, after the water is introduced through a mesh-like multi-point upward flow uniform water distribution system to form a small-disturbance laminar flow, and based on the isolation effect of the sludge layer. Influent and effluent occur simultaneously, and the water is distributed in a small-disturbance laminar flow manner, without disturbing the upper treated water. During this drainage process, the water level in the tank remains constant, allowing drainage without adjusting the decanter height. Then, after influent stops, the decanter is lowered for drainage. This overcomes the problem of large total water loss caused by conventional reactors that can only drain water by lowering the decanter. Simultaneous influent and effluent reduce the fluctuation range of the effluent level and reduce the overall water loss of the reactor.

[0054] In this application, a sequencing batch multi-stage AO (Automatic Aeration) system, i.e., multi-stage influent, employs at least two stages. The wastewater treatment process is illustrated below using a two-stage influent and a one-stage external carbon source addition as an example, including: Step 1), utilizing the first influent to consume residual nitrate nitrogen in the tank, followed by aeration to generate new nitrate nitrogen. Step 2), utilizing the second influent to consume the nitrate nitrogen generated in the first influent until the carbon source in the raw water is depleted, and then aeration to generate new nitrate nitrogen. Step 3), adding an external carbon source to reduce the nitrate nitrogen concentration in the water to the effluent set value, with aerobic aeration ensuring the effluent carbon concentration meets the standard. By using at least two stages of influent and a mesh-like multi-point upward flow uniform water distribution system, the subsequent stages can maximize the utilization of the carbon source in the raw water, improving the overall denitrification effect of the reactor, increasing the raw water carbon source utilization rate, and enhancing the denitrification rate, thus achieving the goal of enhanced denitrification.

[0055] Furthermore, such as Figure 6 As shown in the figure, the full cycle process of two-stage water intake and one-stage external carbon source addition in this embodiment is as follows: Stage 1 water intake (simultaneously relying on water intake for initial drainage) → drainage (after water intake stops, drainage is carried out using a decanter, which is connected to a drainage pipe and does not require a drainage hole) → Stage 1 anoxic reaction (stirring) → Stage 1 aerobic reaction (bottom aeration) → Stage 2 water intake (stirring) → Stage 2 anoxic reaction (stirring) → Stage 2 aerobic reaction (bottom aeration) → Stage 3 anoxic reaction (stirring, external carbon source addition) → Stage 3 aerobic reaction (bottom aeration) → sedimentation → drainage, sludge removal → idle.

[0056] In addition, if three or more stages of water intake and one stage of external carbon source addition are used, the operation of the first stage of water intake is the same as in the above embodiment, while the water intake of the remaining stages is the same as the two-stage water intake treatment steps in the above embodiment; finally, the one-stage external carbon source addition stage is performed.

[0057] The description in this application is given for illustrative purposes and is not intended to be exhaustive or to limit the application to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of this application and to enable those skilled in the art to understand this application and design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A sequencing batch reactor for enhanced denitrification with step feed, wherein, The sequence batch reactor comprises a water distribution system, a stirring device, an aeration device, a drainage device and an external carbon source adding system, and is characterized in that the sequence batch reactor for enhanced denitrification is a multi-cell structure arranged in parallel. The water distribution system adopts a net-shaped multi-point upflow uniform water distribution system for multi-stage water feeding, and comprises a water inlet channel arranged along the top of the reactor, a water inlet shaft arranged in each cell and connected with the water inlet channel, a bottom water distribution channel arranged along the bottom layer of each cell and connected with the water inlet shaft, and a plurality of water distribution pipes arranged in each cell and connected with the bottom water distribution channel; wherein the water inlet channel, the water inlet shaft and the bottom water distribution channel are integrally formed by reinforced concrete pouring with the pool body; the bottom water distribution channel is arranged along the middle of the cell, the plurality of water distribution pipes are uniformly distributed on both sides of the bottom water distribution channel, the bottom water distribution channel is perpendicular to the water inlet shaft, and the projection of the bottom water distribution channel on the water inlet channel is perpendicular; the plurality of water distribution pipes in each cell are arranged horizontally and spaced apart from the bottom of the cell, the bottom of the water distribution pipe is provided with a water outlet hole opening towards the bottom of the cell to form a disturbed laminar flow when water is fed; an electric gate is arranged at the connection between the water inlet shaft and the water inlet channel; at least one stage of water feeding is carried out in the water lifting tank based on the isolation of the sludge layer while the water level in the water body is raised after the disturbed laminar flow is formed by feeding water through the net-shaped multi-point upflow uniform water distribution system. The external carbon source adding system adopts a net-shaped multi-point uniform dosing system, and the carbon source adding pipeline is arranged along the top of the pool and comprises a main pipeline arranged along the top walkway plate of the pool and a plurality of dosing branch pipelines arranged on the top of each cell and connected with the main pipeline, wherein an electric valve is arranged at the branch of the main pipeline connected with the dosing branch pipeline; the plurality of dosing branch pipelines on the top of each cell form a ring, and each dosing branch pipeline is provided with a dosing opening downwardly opening at intervals. The multi-stage water feeding enhanced denitrification comprises at least two stages of water feeding and one stage of external carbon source adding, wherein the residual nitrate nitrogen in the pool is consumed by one stage of water feeding, and then new nitrate nitrogen is generated by aeration; the nitrate nitrogen generated in the previous stage of water feeding is consumed by two stages of water feeding until the carbon source in the raw water is exhausted, and then new nitrate nitrogen is generated by aeration; the external carbon source is added after the two stages of water feeding to reduce the concentration of nitrate nitrogen in the water to a set value of the effluent, and the aeration ensures that the carbon concentration of the effluent meets the standard.

2. The sequencing batch reactor for enhanced denitrification with step feed according to claim 1, wherein The gap between the water distribution pipe and the bottom of the pool is 40-60 mm, and the distance between adjacent two water distribution pipes is 450-550 mm; the cross-sectional shape of the water distribution pipe is semicircular, triangular or rectangular; the water distribution pipe is made of stainless steel.

3. The sequencing batch reactor for enhanced denitrification with step feed according to claim 2, characterized in that, Two rows of water outlet holes are arranged at the bottom of each water distribution pipe; the distance between the two rows of water outlet holes is 55-65 mm; and the aperture of the water outlet hole is 25-35 mm.

4. The sequencing batch reactor for enhanced denitrification with step feed according to claim 1, wherein The interval of the dosing branch pipelines on the top of each cell is 3-5 m, and each dosing branch pipeline is provided with a dosing opening at intervals of 3-5 m.

5. The sequencing batch reactor for enhanced denitrification with step feed according to claim 1, characterized in that, Further comprising: a control system connected with the water distribution system, the stirring device, the aeration device, the drainage device and the external carbon source adding system; and the control system is interlocked with the liquid level meter in the pool.

6. A wastewater treatment method using multi-stage water feeding, characterized by, The sequence batch reactor for enhanced denitrification by multi-stage water feeding according to any one of claims 1-5 is used for sewage treatment, and multi-stage water feeding is used during sewage treatment.

7. The method of claim 6, wherein the method further comprises, At least one stage of water in multi-stage water is in the water through the net multi-point uniform water distribution system to form the disturbance layer flow, and based on the isolation of sludge layer, the initial drainage is carried out while the water level in the water lifting tank.

8. The method of wastewater treatment with multiple stages of water input according to any of claims 6-7, characterized in that, At least comprising: two-stage water and one-stage adding external carbon source; Wherein, the residual nitrate nitrogen in the water consumption tank is consumed by one-stage water, and then new nitrate nitrogen is generated by aeration; the nitrate nitrogen generated by the previous stage of water is consumed by two-stage water to the carbon source exhaustion in raw water, and new nitrate nitrogen is generated by aeration; the concentration of nitrate nitrogen in water is reduced to the set value of effluent by adding external carbon source after two-stage water, and aeration ensures that the carbon concentration of effluent meets the standard.

9. The method of claim 8, wherein the method further comprises, The steps include: 1-stage water is carried out, and initial drainage is carried out by water; drainage is carried out by drainage device after water stop; 1-stage anoxic reaction is carried out by stirring; 1-stage aerobic reaction is carried out by aeration; 2-stage water is carried out; 2-stage anoxic reaction is carried out by stirring; 2-stage aerobic reaction is carried out by aeration; 3-stage anoxic reaction is carried out by stirring and adding external carbon source; 3-stage aerobic reaction is carried out by aeration; sedimentation; drainage and sludge discharge are carried out, and idle is carried out.

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