Wastewater treatment system and method

Abstract

The present application provides a wastewater treatment system and method, wherein the system includes a high-load carbonization / denitrification reaction tank, a secondary sedimentation tank, a one-stage anaerobic ammonium oxidation reactor, a nitrification reactor and an anaerobic ammonium oxidation reactor connected in sequence through pipelines; an inlet pipeline connected to the water inlet of the high-load carbonization / denitrification reaction tank; and an outlet pipeline connected to the water outlet of the anaerobic ammonium oxidation reactor. The application of the present application for wastewater treatment can effectively improve the removal rate of total nitrogen, ensure that the final effluent water quality meets the standard, and does not require strict control of the aeration volume, has low complexity, low difficulty in operation, is easy to control and implement, does not require access to a deep treatment process section, does not require additional addition of a carbon source, can effectively reduce the treatment cost, and is conducive to practical application and on-site promotion.

Description

Technical Field

[0001] The present application relates to the technical field of wastewater treatment, and in particular to a wastewater treatment system and method. Background Art

[0002] In the field of wastewater treatment technology, high-ammonia nitrogen and high-organic wastewater has the characteristics of high pollution, great environmental harm, high difficulty in treatment, and high treatment cost, and has always been the focus and difficulty in the field of wastewater treatment technology. In the existing technology, the traditional nitrification-denitrification process is mainly used to treat high-ammonia nitrogen and high-organic wastewater, which has the problems of high energy consumption, large floor space, and high operating cost. The anaerobic ammonia oxidation process to treat high-ammonia nitrogen and high-organic wastewater has the advantages of low energy consumption, small floor space, and greatly reduced operating costs. However, in actual applications, there are problems such as high difficulty in operation, unstable effluent water quality, and low nitrogen removal efficiency. At the same time, since the concentrations of nitrogen pollutants and organic matter in high-ammonia nitrogen and high-organic wastewater are both high, in order to ensure that the final water quality meets the standards in actual application, it is also necessary to connect the deep treatment process section in the later stage of the anaerobic ammonia oxidation process to achieve deep denitrification, which makes the overall process complicated and the treatment cost high, which is not conducive to on-site application and promotion. Summary of the invention

[0003] In view of this, the purpose of this application is to propose a wastewater treatment system and method to solve the above technical problems.

[0004] In a first aspect of the present application, a wastewater treatment system is provided, comprising:

[0005] A high-load carbonization / denitrification reaction tank, a secondary sedimentation tank, a one-stage anaerobic ammonium oxidation reactor, a nitrite reactor and an anaerobic ammonium oxidation reactor are connected in sequence through pipelines;

[0006] A water inlet pipe connected to the water inlet of the high-load carbonization / denitrification reaction tank, used to guide the wastewater to be treated into the high-load carbonization / denitrification reaction tank for treatment;

[0007] A water outlet pipe connected to the water outlet of the anaerobic ammonium oxidation reactor, used to discharge the treated wastewater out of the system;

[0008] A nitrification liquid reflux pipeline connecting the effluent pipeline and the high-load carbonization / denitrification reaction tank is used to reflux part of the effluent from the effluent pipeline to the high-load carbonization / denitrification reaction tank;

[0009] A first bypass pipe connecting the one-stage anaerobic ammonium oxidation reactor and the one-stage anaerobic ammonium oxidation reactor is used to guide the effluent of the one-stage anaerobic ammonium oxidation reactor into the one-stage anaerobic ammonium oxidation reactor;

[0010] A second bypass pipe connecting the one-stage anaerobic ammonium oxidation reactor and the outlet pipe is used to guide the outlet water of the one-stage anaerobic ammonium oxidation reactor into the outlet pipe.

[0011] Furthermore, it also includes:

[0012] A segmented water inlet pipe connecting the secondary sedimentation tank and the anaerobic ammonium oxidation reactor, used to guide part of the effluent from the secondary sedimentation tank into the anaerobic ammonium oxidation reactor;

[0013] And / or, a nitrite liquid reflux pipeline connecting the nitrite reactor and the one-stage anaerobic ammonium oxidation reactor is used to reflux part of the effluent from the nitrite reactor to the one-stage anaerobic ammonium oxidation reactor.

[0014] Furthermore, the high-load carbonization / denitrification reaction tank includes an anoxic tank for realizing denitrification reaction and an aerobic tank for degrading organic matter. The anoxic tank, the aerobic tank and the secondary sedimentation tank are connected in sequence through pipelines. The water inlet of the anoxic tank is connected to the water inlet pipeline; the nitrification liquid reflux pipeline is connected to the anoxic tank to return part of the effluent from the effluent pipeline to the anoxic tank.

[0015] A second aspect of the present application provides a wastewater treatment method, which is applied to a wastewater treatment system described in the first aspect, comprising:

[0016] Obtaining the total nitrogen concentration, ammonia nitrogen concentration and nitrite nitrogen concentration of the effluent from the one-stage anaerobic ammonium oxidation reactor;

[0017] In response to determining that the total nitrogen concentration is greater than or equal to a first threshold, and the ammonia nitrogen concentration is greater than or equal to a second threshold, enabling a first strategy;

[0018] The first strategy includes:

[0019] Closing the first override pipe and the second override pipe;

[0020] The nitrite reactor and the anaerobic ammonium oxidation reactor are connected and activated, and the effluent of the one-stage anaerobic ammonium oxidation reactor is sequentially passed into the nitrite reactor and the anaerobic ammonium oxidation reactor for treatment;

[0021] The nitrification liquid reflux pipe and the outlet pipe are connected, and the outlet water of the anaerobic ammonia oxidation reactor is passed into the outlet pipe. Part of the outlet water in the outlet pipe is returned to the high-load carbonization / denitrification reaction tank through the nitrification liquid reflux pipe for further treatment, and the other part is directly discharged from the system.

[0022] Further, in response to determining that the total nitrogen concentration is greater than or equal to a first threshold, and the nitrite nitrogen concentration is greater than or equal to a third threshold, activating a second strategy;

[0023] The second strategy includes:

[0024] Closing the nitrification reactor and the second bypass pipe;

[0025] Activating the anaerobic ammonium oxidation reactor and connecting it to the first bypass pipe to pass the effluent of the one-stage anaerobic ammonium oxidation reactor into the anaerobic ammonium oxidation reactor for treatment;

[0026] The nitrification liquid reflux pipe and the outlet pipe are connected to pass the outlet water of the anaerobic ammonia oxidation reactor into the outlet pipe, part of the outlet water of the outlet pipe is returned to the high-load carbonization / denitrification reaction tank through the nitrification liquid reflux pipe for further treatment, and the other part is directly discharged from the system.

[0027] Further, in response to determining that the total nitrogen concentration is less than a first threshold, a third strategy is enabled;

[0028] The third strategy includes:

[0029] Closing the nitrite reactor, the anaerobic ammonium oxidation reactor and the first bypass pipeline;

[0030] The second bypass pipe, the nitrification liquid reflux pipe and the outlet pipe are connected to directly pass the effluent of the one-stage anaerobic ammonia oxidation reactor into the outlet pipe, part of the effluent from the outlet pipe is refluxed to the high-load carbonization / denitrification reaction tank through the nitrification liquid reflux pipe for further treatment, and the other part is directly discharged from the system.

[0031] Furthermore, the first strategy and the second strategy also include:

[0032] Connecting the segmented water inlet pipe to guide part of the effluent from the secondary sedimentation tank into the anaerobic ammonium oxidation reactor;

[0033] The third strategy also includes: closing the segmented water inlet pipeline;

[0034] And / or, the first strategy further includes:

[0035] Connecting the nitrite liquid reflux pipeline, returning part of the effluent from the nitrite reactor to the one-stage anaerobic ammonium oxidation reactor through the nitrite liquid reflux pipeline, and passing another part of the effluent into the anaerobic ammonium oxidation reactor for further treatment;

[0036] The second strategy and the third strategy also include: closing the nitrite liquid reflux pipeline.

[0037] Further, the flow rate of the segmented water inlet pipe in the first strategy is calculated by the following formula: Q0=0.76Q1*C1 / C2;

[0038] The flow rate of the segmented water inlet pipe in the second strategy is calculated by the following formula: Q0 = 0.76Q2*C3 / C2;

[0039] Among them, Q0 is the flow rate of the segmented water inlet pipe, Q1 is the total effluent flow of the nitrite reactor, C1 is the nitrite nitrogen concentration of the effluent of the nitrite reactor, and C2 is the ammonia nitrogen concentration of the effluent of the secondary sedimentation tank; Q2 is the total effluent flow of the one-stage anaerobic ammonium oxidation reactor, and C3 is the nitrite nitrogen concentration of the effluent of the one-stage anaerobic ammonium oxidation reactor.

[0040] Furthermore, the first threshold is 70 mg / L, the second threshold is 45 mg / L, and the third threshold is 50 mg / L.

[0041] Furthermore, the reflux ratio of the nitrite liquid reflux pipeline is 20% to 50%, and the reflux ratio of the nitrate liquid reflux pipeline is 200% to 300%.

[0042] As can be seen from the above, the present application provides a wastewater treatment system and method, in which denitrification and organic matter degradation are carried out in a high-load carbonization / denitrification reaction tank to achieve the removal of organic matter, and the treated mixed liquid enters the secondary sedimentation tank for mud and water separation; in a one-stage anaerobic ammonium oxidation reactor, ammonia nitrogen in the influent is oxidized to nitrite nitrogen, and the generated nitrite nitrogen undergoes anaerobic ammonium oxidation reaction with ammonia nitrogen in the influent to generate nitrogen gas, thereby removing ammonia nitrogen in the wastewater to be treated; in the nitrite reactor, the influent is oxidized to nitrite nitrogen, and the generated nitrite nitrogen undergoes anaerobic ammonium oxidation reaction with the ... The ammonia nitrogen is oxidized into nitrite nitrogen; in the anaerobic ammonium oxidation reactor, the ammonia nitrogen and nitrite nitrogen in the influent are used as substrates to undergo anaerobic ammonium oxidation reaction to generate nitrogen gas and a small amount of nitrate nitrogen, thereby removing the nitrogen-containing pollutants remaining in the effluent from the previous stage; the nitrification liquid reflux pipeline is used to return part of the effluent from the effluent pipeline to the high-load carbonization / denitrification reaction tank to achieve the reflux of the nitrification liquid, and the nitrate nitrogen generated in the anaerobic ammonium oxidation process is removed by denitrification in the high-load carbonization / denitrification reaction tank, thereby achieving further removal of total nitrogen. When the present application performs wastewater treatment, ammonia nitrogen is initially removed through a one-stage anaerobic ammonium oxidation reactor. When the effluent water quality of the one-stage anaerobic ammonium oxidation reactor still does not meet the standard, the nitrite reactor and the anaerobic ammonium oxidation reactor can be used to further remove the total nitrogen. The nitrate nitrogen produced by the anaerobic ammonium oxidation process is refluxed to the high-load carbonization / denitrification reaction tank through the nitrification liquid reflux pipeline for denitrification treatment, thereby further improving the removal rate of total nitrogen and ensuring that the final effluent water quality meets the standard. In addition, the aeration volume does not need to be strictly controlled, the operation is of low complexity, the operation is easy, and the control and implementation are easy. There is no need to connect to a deep treatment process section and no additional carbon source is required. The treatment cost can be effectively reduced, which is conducive to practical application and on-site promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 A schematic diagram of a wastewater treatment system in an embodiment of the present application;

[0045] Figure 2 This is a schematic diagram of a wastewater treatment method in an embodiment of the present application when a first strategy is activated;

[0046] Figure 3 This is a schematic diagram of a wastewater treatment method in an embodiment of the present application when the second strategy is activated;

[0047] Figure 4 This is a schematic diagram of a wastewater treatment method in an embodiment of the present application when the third strategy is activated;

[0048] The above-mentioned Figure 2 ~Attached Figure 4 The solid line part in the diagram indicates the connected or enabled state, and the dotted line part indicates the closed state.

[0049] Explanation of the reference numerals: 11-high-load carbonization / denitrification reaction tank; 12-second sedimentation tank; 13-one-stage anaerobic ammonium oxidation reactor; 14-nitritation reactor; 15-anaerobic ammonium oxidation reactor; 21-water inlet pipe; 22-water outlet pipe; 23-nitrification liquid reflux pipe; 24-first bypass pipe; 25-second bypass pipe; 26-nitrification liquid reflux pipe; 27-segmented water inlet pipe. DETAILED DESCRIPTION

[0050] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0051] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0052] In the field of wastewater treatment technology, the content of ammonia nitrogen and organic matter in high-ammonia nitrogen and high-organic matter wastewater is high, and the nitrogen pollutants in the wastewater are difficult to remove. It has the characteristics of high pollution level, great environmental harm, great difficulty in treatment, and high treatment cost. Therefore, the treatment of high-ammonia nitrogen and high-organic matter wastewater has always been a difficulty and focus in the field of wastewater treatment technology.

[0053] In the prior art, the traditional nitrification-denitrification process is mainly used to treat high-ammonia nitrogen and high-organic wastewater, which has the problems of high energy consumption, large floor space and high operating cost. The anaerobic ammonia oxidation process can save a higher aeration energy consumption than the traditional biological denitrification process due to its unique denitrification reaction path of biological treatment, and does not require additional carbon source, which can greatly reduce the treatment cost. Therefore, it can be used in industrial wastewater treatment, especially the treatment of high-ammonia nitrogen and high-organic wastewater. In the anaerobic ammonia oxidation reaction, the ammonia nitrogen in the wastewater undergoes partial short-range nitrification to generate nitrite nitrogen, and the nitrite nitrogen and ammonia nitrogen directly react to generate nitrogen gas under the action of anaerobic ammonia oxidizing bacteria (ANAMMOX), thereby achieving the removal of ammonia nitrogen. In the traditional nitrification / denitrification process, about 2 mol of oxygen and a certain amount of carbon source are required to remove 1 mol of ammonia nitrogen, while in the anaerobic ammonia oxidation process, only about 0.85 mol of oxygen is consumed to remove 1 mol of ammonia nitrogen, which can save aeration energy consumption. At the same time, anaerobic ammonia oxidation is an autotrophic metabolic process, and no additional carbon source is required, so it can further save treatment costs.

[0054] When using the anaerobic ammonium oxidation process to treat high-ammonia nitrogen and high-organic wastewater, the main technical route used is a one-stage anaerobic ammonium oxidation process, that is, a fully autotrophic denitrification process (CANON process). In the one-stage anaerobic ammonium oxidation process, it is required to enrich ammonia oxidizing bacteria and anaerobic ammonium oxidizing bacteria in the same reactor, and use ammonia oxidizing bacteria to achieve the nitrosation of part of the ammonia nitrogen to obtain nitrite nitrogen. At the same time, the nitrosation process consumes oxygen to create the anaerobic environment required for the anaerobic ammonium oxidation process, and then uses anaerobic ammonium oxidizing bacteria to react nitrite nitrogen with the remaining ammonia nitrogen to generate nitrogen gas and a small amount of nitrate nitrogen to achieve the removal of ammonia nitrogen. Ammonia oxidizing bacteria is an aerobic bacteria, and anaerobic ammonium oxidizing bacteria is an anaerobic bacteria. The environmental conditions required for the two bacterial communities to maintain activity are different, so how to maintain the long-term steady-state operation of the one-stage anaerobic ammonium oxidation process has always been a technical difficulty in this field. In practical applications, the dynamic balance of ammonia oxidizing bacteria and anaerobic ammonium oxidizing bacteria is usually maintained by strictly controlling the aeration process. When aeration is insufficient, the oxygen content in the system is insufficient, and the accumulation of nitrite nitrogen is insufficient, which makes it difficult to effectively remove ammonia nitrogen and causes ammonia nitrogen accumulation. When aeration is excessive, the oxygen content in the system is high, and the ammonia-oxidizing bacteria are active, causing excessive accumulation of nitrite nitrogen. At the same time, in the anaerobic ammonia oxidation reaction, ammonia nitrogen and nitrite nitrogen are both substrates and inhibitors of the anaerobic ammonia oxidation reaction. No matter which substance increases in concentration, it will inhibit the activity of anaerobic ammonia-oxidizing bacteria, and ultimately lead to substandard effluent quality. In addition, in the operation of a one-stage anaerobic ammonia oxidation process reactor, it is usually necessary to maintain a certain upward flow rate, and the aeration volume will affect the upward flow rate. Therefore, in the one-stage anaerobic ammonia oxidation process, the regulation of the aeration process must not only balance the demand for oxygen for the nitrite reaction, the anaerobic environment required for anaerobic ammonia oxidation, but also balance the stirring of the hydraulic flow state. The control requirements are high and the operation is difficult, which makes the control of the entire reaction system difficult, and it is very easy to have unstable effluent water quality, which is difficult to operate and apply in practical applications.

[0055] In a one-stage anaerobic ammonium oxidation reaction, about 0.11 mol of nitrate nitrogen will be produced for every 1 mol of ammonia nitrogen removed. Therefore, when the influent ammonia nitrogen concentration is high, even if the anaerobic ammonium oxidation reaction efficiency is high, the total nitrogen will inevitably fail to meet the standard due to the high concentration of nitrate nitrogen produced. Therefore, it is usually necessary to add a deep treatment process section to the back of the one-stage anaerobic ammonium oxidation reaction to carry out deep denitrification to achieve the removal of nitrate nitrogen. For example, the AO process (anaerobic aerobic process) with nitrification-denitrification traditional biological denitrification as the technical route requires continued aeration and additional addition of carbon source in this process, which increases the complexity of the process and the treatment cost, and is not conducive to practical application and promotion.

[0056] Based on the above situation, the present disclosure provides a wastewater treatment system, such as Figure 1As shown, it can effectively remove ammonia nitrogen and organic matter in high-ammonia nitrogen and high-organic matter wastewater, so that the effluent water quality meets the standard, and can effectively reduce the difficulty of process control and treatment costs, which is conducive to practical application and promotion, including:

[0057] A high-load carbonization / denitrification reaction tank 11, a secondary sedimentation tank 12, a one-stage anaerobic ammonium oxidation reactor 13, a nitrite reactor 14 and an anaerobic ammonium oxidation reactor 15 are connected in sequence through pipelines;

[0058] A water inlet pipe 21 connected to the water inlet of the high-load carbonization / denitrification reaction tank 11, used to guide the wastewater to be treated into the high-load carbonization / denitrification reaction tank 11 for treatment;

[0059] An outlet pipe 22 connected to the outlet of the anaerobic ammonium oxidation reactor 15 is used to discharge the treated wastewater out of the system;

[0060] A nitrification liquid return pipe 23 connecting the effluent pipe 22 and the high-load carbonization / denitrification reaction tank 11 to return part of the effluent from the effluent pipe 22 to the high-load carbonization / denitrification reaction tank 11;

[0061] A first bypass pipe 24 connecting the one-stage anaerobic ammonium oxidation reactor 13 and the anaerobic ammonium oxidation reactor 15, for guiding the effluent of the one-stage anaerobic ammonium oxidation reactor 13 into the anaerobic ammonium oxidation reactor 15;

[0062] The second bypass pipe 25 connecting the one-stage anaerobic ammonium oxidation reactor 13 and the outlet pipe 22 is used to guide the outlet water of the one-stage anaerobic ammonium oxidation reactor 13 into the outlet pipe 22 .

[0063] In this system, the wastewater to be treated is led into the high-load carbonization / denitrification reaction tank 11 through the water inlet pipe 21 for treatment, and finally the treated wastewater that meets the discharge standards is discharged from the system through the water outlet pipe 22. In the high-load carbonization / denitrification reaction tank 11, denitrification and organic matter degradation occur, and the treated mixed solution enters the secondary sedimentation tank 12 for mud and water separation, and the effluent from the secondary sedimentation tank 12 enters the one-stage anaerobic ammonia oxidation reactor 13 for reaction. In the one-stage anaerobic ammonia oxidation reactor 13, ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria are enriched, and the ammonia nitrogen in the influent is oxidized to nitrite nitrogen by ammonia oxidizing bacteria. The generated nitrite nitrogen and the ammonia nitrogen in the influent undergo anaerobic ammonia oxidation reaction under the action of anaerobic ammonia oxidizing bacteria to generate nitrogen gas and a small amount of nitrate nitrogen, thereby removing the ammonia nitrogen in the wastewater to be treated. Nitrite bacteria are enriched in the nitrite reactor 14, and the ammonia nitrogen in the influent can be oxidized to nitrite nitrogen by nitrite bacteria. Anaerobic ammonium oxidation reactor 15 is enriched with anaerobic ammonium oxidation bacteria, which use ammonia nitrogen and nitrite nitrogen in the influent as substrates to generate nitrogen gas and a small amount of nitrate nitrogen through anaerobic ammonium oxidation reaction, thereby removing nitrogen-containing pollutants remaining in the effluent from the previous stage and achieving effluent water quality standards. Nitrification liquid reflux pipeline 23 is used to return part of the effluent from the effluent pipeline 22 to the high-load carbonization / denitrification reaction tank 11 to achieve reflux of nitrification liquid, and remove nitrate nitrogen generated in the anaerobic ammonium oxidation process through denitrification in the high-load carbonization / denitrification reaction tank 11. When the system is used for wastewater treatment, ammonia nitrogen is removed through the one-stage anaerobic ammonium oxidation reactor 13. When the effluent water quality of the one-stage anaerobic ammonium oxidation reactor 13 still does not meet the standard, the nitrite reactor 14 or the anaerobic ammonium oxidation reactor 15 can be used to further remove the total nitrogen. The nitrate nitrogen produced by the anaerobic ammonium oxidation process is refluxed to the high-load carbonization / denitrification reaction tank 11 through the nitrification liquid reflux pipeline 23 for denitrification treatment, thereby further improving the removal rate of total nitrogen and ensuring that the final effluent water quality meets the standard. The system does not require strict control of the aeration volume, has low complexity, low operating difficulty, is easy to control and implement, does not require access to a deep treatment process section, does not require additional carbon source addition, can effectively reduce the treatment cost, and is conducive to practical application and on-site promotion.

[0064] In some embodiments, Figure 1 As shown, it also includes: a segmented water inlet pipe 27 connecting the secondary sedimentation tank 12 and the anaerobic ammonium oxidation reactor 15, which is used to guide part of the effluent from the secondary sedimentation tank 12 into the anaerobic ammonium oxidation reactor 15. After the mud and water are separated from the secondary sedimentation tank 12, part of the effluent enters the one-stage anaerobic ammonium oxidation reactor 13, and the other part enters the anaerobic ammonium oxidation reactor 15 through the segmented water inlet pipe 27, providing ammonia nitrogen for the anaerobic ammonium oxidation reaction of the two reactors.

[0065] In some embodiments, Figure 1As shown, it also includes: a nitrite liquid reflux pipeline 26 connecting the nitrite reactor 14 and the one-stage anaerobic ammonium oxidation reactor 13, which is used to reflux part of the effluent of the nitrite reactor 14 to the one-stage anaerobic ammonium oxidation reactor 13. The nitrite liquid reflux pipeline 26 can reflux part of the effluent of the nitrite reactor 14 to the one-stage anaerobic ammonium oxidation reactor 13, realize the reflux of the nitrite liquid, and provide nitrite nitrogen for the anaerobic ammonium oxidation reaction in the one-stage anaerobic ammonium oxidation reactor 13.

[0066] In some embodiments, one end of the segmented water inlet pipe 27 can be connected to the pipe connecting the secondary sedimentation tank 12 and the one-stage anaerobic ammonium oxidation reactor 13, or directly connected to the secondary sedimentation tank 12, and the other end can be connected to the pipe connecting the nitrite reactor 14 and the anaerobic ammonium oxidation reactor 15, or directly connected to the anaerobic ammonium oxidation reactor 15; one end of the nitrite liquid reflux pipe 26 can be connected to the pipe connecting the nitrite reactor 14 and the anaerobic ammonium oxidation reactor 15, or directly connected to the nitrite reactor 14, and the other end can be connected to the pipe connecting the secondary sedimentation tank 12 and the one-stage anaerobic ammonium oxidation reactor 13, or directly connected to the one-stage anaerobic ammonium oxidation reactor 13. In actual application, adaptive adjustments can be made according to actual working conditions, etc., and there is no specific limitation. When both ends of the segmented water inlet pipe 27 and the nitrite liquid reflux pipe 26 are connected to the pipes, on the pipe connecting the secondary sedimentation tank 12 and the one-stage anaerobic ammonium oxidation reactor 13, the connection point of the segmented water inlet pipe 27 is located before the connection point of the nitrite liquid reflux pipe 26, and on the pipe connecting the nitrite reactor 14 and the anaerobic ammonium oxidation reactor 15, the connection point of the segmented water inlet pipe 27 is located after the connection point of the nitrite liquid reflux pipe 26, thereby ensuring that the nitrite liquid can smoothly reflux to the one-stage anaerobic ammonium oxidation reactor 13, and ensuring that part of the effluent from the secondary sedimentation tank 12 can be effectively drained to the anaerobic ammonium oxidation reactor 15 through the segmented water inlet pipe 27.

[0067] In some embodiments, Figure 1 As shown, the connection point between the second bypass pipe 25 and the outlet pipe 22 is located before the connection point between the nitrification liquid reflux pipe 23 and the inlet pipe 21, thereby ensuring that the nitrification liquid can be smoothly refluxed to the front end of the process, that is, the nitrate nitrogen can be smoothly refluxed to the high-load carbonization / denitrification reaction tank 11 for denitrification and denitrification, thereby ensuring the effective removal of nitrate nitrogen and further improving the total nitrogen removal rate.

[0068] In some embodiments, the high-load carbonization / denitrification reaction tank 11 includes an anoxic tank for realizing denitrification reaction and an aerobic tank for degrading organic matter. The anoxic tank, the aerobic tank and the secondary sedimentation tank 12 are connected in sequence through pipelines. The water inlet of the anoxic tank is connected to the water inlet pipeline 21; the nitrification liquid reflux pipeline 23 is connected to the anoxic tank to return part of the effluent from the effluent pipeline 22 to the anoxic tank.

[0069] A stirring device is provided in the anoxic tank. The wastewater to be treated first enters the anoxic tank (i.e., tank A) through the water inlet pipe 21. The nitrified liquid refluxed through the nitrified liquid reflux pipe 23 also enters the anoxic tank. The stirring device is used to stir the influent, so that the influent is fully mixed. The rich organic matter in the anoxic tank acts as a carbon source and reacts with the nitrate nitrogen produced by the anaerobic ammonia oxidation reaction to undergo a denitrification reaction, thereby achieving denitrification. The effluent from the anoxic tank enters the aerobic tank (i.e., tank O). The aerobic tank is provided with an aeration device, and aerobic heterotrophic bacteria are cultured. The aerobic heterotrophic bacteria are used to degrade the organic matter in the influent, thereby achieving the removal of the organic matter in the wastewater to be treated. At this time, the total nitrogen in the effluent from the aerobic tank is mainly ammonia nitrogen. The mixed liquor of the effluent from the aerobic tank enters the secondary sedimentation tank 12 for mud-water separation. The activated sludge concentrated in the secondary sedimentation tank 12 is returned to the anoxic tank, and the effluent enters the subsequent process section for further treatment until the effluent water quality meets the standard.

[0070] In some embodiments, the wastewater to be treated is high-ammonia nitrogen and high-organic wastewater. High-ammonia nitrogen and high-organic wastewater is a relatively common industrial wastewater, which has the characteristics of high organic content and high ammonia nitrogen content. Sludge digestion liquid, restaurant biogas liquid, garbage leachate, etc. are all typical high-ammonia nitrogen and high-organic wastewater. When using the present application to treat high-ammonia nitrogen and high-organic wastewater, while effectively removing organic matter and ammonia nitrogen, the entire process does not require additional carbon source addition, nor does it require strict control of the aeration process. The processing cost, operation difficulty, and process complexity are all low, which is conducive to practical application and on-site promotion.

[0071] In some embodiments, the one-stage anaerobic ammonium oxidation reactor 13 is an upflow sludge bed reactor or a moving bed biofilm reactor. The upflow sludge bed reactor has the characteristics of simple structure, high load rate, short hydraulic retention time, low energy consumption and no need for a separate sludge return device, and has broad application prospects. The moving bed biofilm reactor can operate continuously, is not prone to clogging, and does not require backwashing. It also has the characteristics of resistance to shock loads, low sludge production, and long sludge age. In actual application, an upflow sludge bed reactor or a moving bed biofilm reactor can be selected as the one-stage anaerobic ammonium oxidation reactor 13 according to the specific circumstances of the application scenario, and other reactors that can realize the one-stage anaerobic ammonium oxidation process can also be used as the one-stage anaerobic ammonium oxidation reactor 13, without specific restrictions.

[0072] Some embodiments of the present application provide a wastewater treatment method, which can be used to treat high-ammonia nitrogen and high-organic matter wastewater, and is applied to a wastewater treatment system described in any of the above embodiments, comprising:

[0073] Obtaining the total nitrogen concentration, ammonia nitrogen concentration and nitrite nitrogen concentration of the effluent from the one-stage anaerobic ammonium oxidation reactor 13;

[0074] In response to determining that the total nitrogen concentration is greater than or equal to a first threshold, and the ammonia nitrogen concentration is greater than or equal to a second threshold, enabling a first strategy;

[0075] The first strategy includes:

[0076] Close the first overriding pipe 24 and the second overriding pipe 25;

[0077] The nitrite reactor 14 and the anaerobic ammonium oxidation reactor 15 are connected and activated, and the effluent of the one-stage anaerobic ammonium oxidation reactor 13 is sequentially passed into the nitrite reactor 14 and the anaerobic ammonium oxidation reactor 15 for treatment;

[0078] The nitrification liquid reflux pipe 23 and the effluent pipe 22 are connected, and the effluent of the anaerobic ammonia oxidation reactor 15 is passed into the effluent pipe 22. Part of the effluent in the effluent pipe 22 is refluxed to the high-load carbonization / denitrification reaction tank 11 through the nitrification liquid reflux pipe 23 for further treatment, and the other part is directly discharged from the system.

[0079] When it is necessary to treat the wastewater to be treated, the high-load carbonization / denitrification reaction tank 11, the secondary sedimentation tank 12 and the one-stage anaerobic ammonium oxidation reactor 13 are connected and activated, and the water inlet pipe 21 is connected. The wastewater to be treated is passed into the high-load carbonization / denitrification reaction tank 11 for reaction by using the water inlet pipe 21. After the treatment of the high-load carbonization / denitrification reaction tank 11 is completed, it is successively passed into the secondary sedimentation tank 12 and the one-stage anaerobic ammonium oxidation reactor 13 for treatment. In the one-stage anaerobic ammonium oxidation reactor 13, ammonia nitrogen is reacted by ammonia oxidizing bacteria to generate nitrite nitrogen, and the generated nitrite nitrogen reacts with the ammonia nitrogen of the influent to generate nitrogen gas under the action of anaerobic ammonium oxidizing bacteria, thereby achieving the removal of ammonia nitrogen. In the above process, aerobic ammonia oxidizing bacteria and strictly anaerobic anaerobic ammonium oxidizing bacteria exist at the same time, so it is necessary to balance the population advantages of ammonia oxidizing bacteria and anaerobic ammonium oxidizing bacteria by strictly controlling the aeration of the one-stage anaerobic ammonium oxidation reactor 13. When aeration is excessive, the activity of anaerobic ammonium oxidizing bacteria will be inhibited, and the nitrite nitrogen produced by the nitrite reaction cannot be reacted in time, which will cause the accumulation of nitrite nitrogen. It is generally believed that when the concentration of nitrite nitrogen reaches 80 mg / L or more, the activity of anaerobic ammonium oxidation will be seriously inhibited, which will cause the system to enter a vicious cycle. Therefore, controlling the aeration volume at a relatively low level can avoid the accumulation of nitrite nitrogen. However, when the aeration volume is controlled at a relatively low level, it is easy to cause insufficient aeration supply, which may cause the nitrite reaction rate of ammonia nitrogen to fail to reach the ideal level, and then the ammonia nitrogen cannot be effectively removed, resulting in excessive ammonia nitrogen in the effluent of the one-stage anaerobic ammonium oxidation reactor 13. Therefore, the aeration process control requirements of the one-stage anaerobic ammonium oxidation reactor 13 are high and the control difficulty is large. In addition, the anaerobic ammonium oxidation reaction will produce about 11% nitrate nitrogen. Even when the anaerobic ammonium oxidation reaction efficiency is high, there may be a situation where the nitrate nitrogen concentration is high and the total nitrogen in the effluent does not meet the standard. Therefore, in actual operation, the effluent conditions in the one-stage anaerobic ammonium oxidation reactor 13 are relatively complex, and the effluent quality is relatively unstable. There may be accumulation of nitrite nitrogen, or excessive ammonia nitrogen concentration, and there may also be a certain amount of nitrate nitrogen.

[0080] In the present application, by obtaining the total nitrogen concentration, ammonia nitrogen concentration and nitrite nitrogen concentration in the effluent of the one-stage anaerobic ammonium oxidation reactor 13, and determining the execution strategy of the subsequent process stage according to the total nitrogen concentration, ammonia nitrogen concentration and nitrite nitrogen concentration, it is possible to effectively deal with the situation where the effluent of the one-stage anaerobic ammonium oxidation reactor 13 is complex and the effluent quality is unstable. When the total nitrogen concentration is greater than or equal to the first threshold value and the ammonia nitrogen concentration is greater than or equal to the second threshold value, it means that the total nitrogen concentration and the ammonia nitrogen concentration are high, the reaction efficiency of the one-stage anaerobic ammonium oxidation reactor 13 is not high, and there may be certain problems with aeration. At this time, the first strategy is activated to further remove ammonia nitrogen from the effluent of the one-stage anaerobic ammonium oxidation reactor 13. In the first strategy, if Figure 2As shown, the first bypass pipe 24 and the second bypass pipe 25 are closed to prevent the effluent of the one-stage anaerobic ammonium oxidation reactor 13 from directly flowing into the anaerobic ammonium oxidation reactor 15 or the effluent pipe 22; the nitrite reactor 14 and the anaerobic ammonium oxidation reactor 15 are connected and enabled, and the nitrification liquid reflux pipe 23 and the effluent pipe 22 are connected. The effluent of the one-stage anaerobic ammonium oxidation reactor 13 first enters the nitrite reactor 14 for treatment. The nitrite bacteria are enriched in the nitrite reactor 14, and the aeration amount required by the nitrite bacteria is provided to the nitrite reactor 14. Under the action of the nitrite bacteria, the ammonia nitrogen in the influent is oxidized to nitrite nitrogen; then the effluent of the nitrite reactor 14 containing nitrite nitrogen is passed into the anaerobic ammonium oxidation reactor 1 5 continues to be treated; the anaerobic ammonium oxidation reactor 15 is enriched with anaerobic ammonium oxidation bacteria, under the action of the anaerobic ammonium oxidation bacteria, ammonia nitrogen and nitrite nitrogen undergo anaerobic ammonium oxidation reaction to generate nitrogen gas and a small amount of nitrate nitrogen, thereby removing the nitrogen-containing pollutants remaining in the one-stage anaerobic ammonium oxidation reactor 13; the effluent of the anaerobic ammonium oxidation reactor 15 is introduced into the effluent pipe 22, and a part of the effluent of the effluent pipe 22 is refluxed to the high-load carbonization / denitrification reaction tank 11 through the nitrification liquid reflux pipe 23 to achieve internal circulation, and the nitrate nitrogen reacts with organic matter in the high-load carbonization / denitrification reaction tank 11 to achieve denitrification and denitrification, and further achieve the removal of total nitrogen, and the other part of the effluent meets the discharge standard and is directly discharged from the system through the effluent pipe 22.

[0081] In some embodiments, in response to determining that the total nitrogen concentration is greater than or equal to a first threshold and the nitrite nitrogen concentration is greater than or equal to a third threshold, a second strategy is enabled;

[0082] The second strategy includes:

[0083] Closing the nitrification reactor 14 and the second bypass pipe 25;

[0084] The anaerobic ammonium oxidation reactor 15 is activated and connected to the first bypass pipe 24 to pass the effluent of the one-stage anaerobic ammonium oxidation reactor 13 into the anaerobic ammonium oxidation reactor 15 for treatment;

[0085] The nitrification liquid reflux pipe 23 and the effluent pipe 22 are connected to pass the effluent of the anaerobic ammonia oxidation reactor 15 into the effluent pipe 22. Part of the effluent from the effluent pipe 22 is refluxed to the high-load carbonization / denitrification reaction tank 11 through the nitrification liquid reflux pipe 23 for further treatment, and the other part is directly discharged from the system.

[0086] When the total nitrogen concentration in the effluent of the one-stage anaerobic ammonium oxidation reactor 13 is greater than or equal to the first threshold value and the nitrite nitrogen concentration is greater than or equal to the third threshold value, it means that the total nitrogen concentration and the nitrite nitrogen concentration are high, and the second strategy is activated at this time. In the second strategy, if Figure 3As shown, since the effluent of the one-stage anaerobic ammonium oxidation reactor 13 contains more nitrite nitrogen at this time, the nitrite reactor 14 does not need to be activated, and the nitrite reactor 14 is directly closed. Since the effluent does not meet the discharge standard at this time, the second bypass pipe 25 is also closed to prevent the effluent of the one-stage anaerobic ammonium oxidation reactor 13 from being directly discharged from the system; then the anaerobic ammonium oxidation reactor 15 is activated, and the first bypass pipe 24, the nitrification liquid reflux pipe 23 and the effluent pipe 22 are connected. The effluent of the one-stage anaerobic ammonium oxidation reactor 13 is directly passed into the anaerobic ammonium oxidation reactor 15 through the first bypass pipe 24, and ammonia nitrogen and nitrite nitrogen undergo anaerobic ammonium oxidation reaction to generate nitrogen gas and a small amount of nitrate nitrogen to achieve the removal of nitrite nitrogen. A part of the effluent of the anaerobic ammonium oxidation reactor 15 is refluxed to the high-load carbonization / denitrification reaction tank 11 through the nitrification liquid reflux pipe 23 to achieve denitrification, and the other part meets the discharge standard and is directly discharged from the system through the effluent pipe 22.

[0087] In some embodiments, in response to determining that the total nitrogen concentration is less than a first threshold, a third strategy is enabled;

[0088] The third strategy includes:

[0089] Close the nitrite reactor 14, the anaerobic ammonium oxidation reactor 15 and the first bypass pipe 24;

[0090] The second bypass pipe 25, the nitrification liquid reflux pipe 23 and the effluent pipe 22 are connected to directly pass the effluent of the one-stage anaerobic ammonia oxidation reactor 13 into the effluent pipe 22. Part of the effluent from the effluent pipe 22 is refluxed to the high-load carbonization / denitrification reaction tank 11 through the nitrification liquid reflux pipe 23 for further treatment, and the other part is directly discharged from the system.

[0091] When the total nitrogen concentration in the effluent of the one-stage anaerobic ammonium oxidation reactor 13 is less than the first threshold value, it means that the total nitrogen concentration is low, the reaction in the one-stage anaerobic ammonium oxidation reactor 13 is relatively ideal, the ammonia nitrogen in the influent can be removed relatively smoothly, and there is no accumulation of nitrite nitrogen. At this time, the third strategy is activated. In the third strategy, if Figure 4As shown, since the reaction of the one-stage anaerobic ammonium oxidation reactor 13 is relatively ideal, most of the ammonia nitrogen in the influent is removed by the one-stage anaerobic ammonium oxidation reactor 13, the ammonia nitrogen removal rate can reach more than 98%, the total nitrogen in the effluent is low, and there is no accumulation of nitrite nitrogen. Therefore, the effluent does not need to be treated by the nitritation reactor 14 and the anaerobic ammonium oxidation reactor 15. The nitritation reactor 14, the anaerobic ammonium oxidation reactor 15 and the first bypass pipe 24 are directly closed, and the second bypass pipe 25, the nitrification liquid reflux pipe 23 and the effluent pipe 22 are connected. The effluent of the one-stage anaerobic ammonium oxidation reactor 13 is directly introduced into the effluent pipe 22 through the second bypass pipe 25. A part of the effluent of the effluent pipe 22 is refluxed to the high-load carbonization / denitrification reaction tank 11 through the nitrification liquid reflux pipe 23 for denitrification, and the other part of the effluent meets the discharge standard and is directly discharged from the system.

[0092] Total nitrogen usually refers to the total amount of nitrogen in various forms in water, including ammonia nitrogen, nitrate nitrogen, nitrite nitrogen and various organic nitrogen. It is one of the important indicators for measuring water quality. Ammonia nitrogen refers to the amount of nitrogen in water in the form of free ammonia or ionized ammonia (NH4 + ) can lead to water eutrophication. It is the main oxygen-consuming pollutant in water bodies, toxic to fish and certain aquatic organisms, and is also one of the important indicators for measuring water quality. Nitrite nitrogen is an intermediate product of the nitrogen cycle and is relatively unstable. It can be oxidized into nitrate nitrogen or reduced to ammonia nitrogen. During the reaction process of the one-stage anaerobic ammonia oxidation reactor 13, since the aeration process is difficult to accurately control, there may be excessive ammonia nitrogen or accumulation of nitrite nitrogen or high nitrate nitrogen content in the effluent. Therefore, in this application, the activation strategy of the subsequent process section is determined by obtaining the total nitrogen concentration, ammonia nitrogen concentration and nitrite nitrogen concentration in the effluent to ensure that the effluent water quality meets the standard. Nitrate nitrogen is mainly removed effectively through the nitrification liquid reflux pipeline 23. In the entire process, the control difficulty is low and easy to achieve. At the same time, it can effectively ensure that various indicators of the effluent water quality meet the standard, which is conducive to on-site application and promotion.

[0093] In some embodiments, Figure 2 to Figure 4 As shown, the first strategy and the second strategy also include:

[0094] Connecting the segmented water inlet pipe 27 to guide part of the effluent from the secondary sedimentation tank 12 into the anaerobic ammonium oxidation reactor 15;

[0095] The third strategy also includes: closing the segmented water inlet pipeline 27 .

[0096] In the first strategy and the second strategy, a portion of the effluent from the secondary sedimentation tank 12 directly enters the anaerobic ammonium oxidation reactor 15 through the segmented water inlet pipe 27 to provide an ammonia nitrogen substrate for the anaerobic ammonium oxidation reaction of the anaerobic ammonium oxidation reactor 15 .

[0097] In some embodiments, Figure 2 to Figure 4 As shown, the first strategy also includes:

[0098] The nitrite liquid reflux pipe 26 is connected to reflux part of the effluent from the nitrite reactor 14 to the one-stage anaerobic ammonium oxidation reactor 13 through the nitrite liquid reflux pipe 26, and the other part of the effluent is passed into the anaerobic ammonium oxidation reactor 15 for further treatment;

[0099] The second strategy and the third strategy also include: closing the nitrite liquid reflux pipeline 26 .

[0100] In the first strategy, Figure 2 As shown, the nitrite reactor 14 is activated. At this time, the nitrite liquid reflux pipe 26 can be connected to return part of the effluent from the nitrite reactor 14 to the one-stage anaerobic ammonium oxidation reactor 13, thereby providing nitrite nitrogen for the anaerobic ammonium oxidation reaction in the one-stage anaerobic ammonium oxidation reactor 13 and promoting the occurrence of the anaerobic ammonium oxidation reaction.

[0101] In some embodiments, the flow rate of the segmented water inlet pipe 27 in the first strategy is calculated by the following formula: Q0 = 0.76Q1*C1 / C2;

[0102] The flow rate of the segmented water inlet pipe 27 in the second strategy is calculated by the following formula: Q0 = 0.76Q2*C3 / C2;

[0103] Among them, Q0 is the flow rate of the segmented water inlet pipe 27, Q1 is the total flow rate of the effluent from the nitrite reactor 14, C1 is the nitrite nitrogen concentration of the effluent from the nitrite reactor 14, and C2 is the ammonia nitrogen concentration of the effluent from the secondary sedimentation tank 12; Q2 is the total flow rate of the effluent from the one-stage anaerobic ammonium oxidation reactor 13, and C3 is the nitrite nitrogen concentration of the effluent from the one-stage anaerobic ammonium oxidation reactor 13.

[0104] In the first strategy, Figure 2 As shown, part of the effluent from the nitrite reactor 14 is mixed with the effluent from the segmented water inlet pipe 27 and then introduced into the anaerobic ammonium oxidation reactor 15. At this time, the flow rate of the segmented water inlet pipe 27 is determined by the concentration of nitrite nitrogen in the effluent from the nitrite reactor 14, that is, calculated by the following formula: Q0 = 0.76Q1*C1 / C2, so that the ratio of ammonia nitrogen to nitrite nitrogen in the influent of the anaerobic ammonium oxidation reactor 15 is 1:1.15. In the second strategy, as Figure 3As shown, the nitrite reactor 14 is closed, the effluent of the one-stage anaerobic ammonium oxidation reactor 13 is directly introduced into the anaerobic ammonium oxidation reactor 15 through the first bypass pipe 24, and part of the effluent of the secondary sedimentation tank 12 is introduced into the anaerobic ammonium oxidation reactor 15 through the segmented water inlet pipe 27 to supplement ammonia nitrogen for its anaerobic ammonium oxidation reaction. At this time, the flow rate of the segmented water inlet pipe 27 is determined by the nitrite nitrogen concentration of the effluent of the one-stage anaerobic ammonium oxidation reactor 13, that is, it is calculated by the following formula: Q0=0.76Q2*C3 / C2.

[0105] In some embodiments, the first threshold is 70 mg / L, the second threshold is 45 mg / L, and the third threshold is 50 mg / L. In the present application, when the total nitrogen concentration of the effluent of the one-stage anaerobic ammonium oxidation reactor 13 is greater than or equal to 70 mg / L (i.e., the first threshold), it means that the total nitrogen content of the effluent of the one-stage anaerobic ammonium oxidation reactor 13 is not up to standard and needs to be subsequently treated. At this time, the subsequent process is further determined according to the ammonia nitrogen concentration and nitrite nitrogen concentration in the effluent. When the total nitrogen concentration of the effluent of the one-stage anaerobic ammonium oxidation reactor 13 is greater than or equal to 70 mg / L, and the ammonia nitrogen concentration is also greater than or equal to 45 mg / L (i.e., the second threshold), it means that the ammonia nitrogen content in the effluent is high. At this time, the first strategy is enabled for treatment. When the nitrite nitrogen concentration is greater than or equal to 50 mg / L (i.e., the third threshold), it means that the nitrite nitrogen content in the effluent exceeds the standard. At this time, the second strategy is enabled for treatment, thereby ensuring that the total nitrogen, ammonia nitrogen and nitrite nitrogen in the effluent are all up to standard. In the present application, the first threshold, the second threshold and the third threshold can be set according to the wastewater discharge standards of various places, or according to actual needs, and can be other values. For example, the first threshold can be 65mg / L, 60mg / L, 55mg / L, 75mg / L, etc., the second threshold can be 40mg / L, 38mg / L, 35mg / L, 48mg / L, 50mg / L, etc., and the third threshold can be 48mg / L, 45mg / L, 52mg / L, 55mg / L, etc., without specific limitation.

[0106] In some embodiments, the nitrification liquid return pipe 23 is connected to the anoxic tank, and the nitrification liquid return pipe 23 is used to realize the nitrification liquid return, and a denitrification reaction occurs in the anoxic tank to achieve denitrification; the effluent of the anoxic tank enters the aerobic tank for organic matter degradation. In the aerobic tank, by controlling the aeration volume and the sludge age, the nitrification rate of ammonia nitrogen is maintained within 10%, and while fully degrading organic matter, the generation of nitrate nitrogen can be effectively avoided.

[0107] In some embodiments, the reflux ratio of the nitrite liquid reflux pipeline 26 is 20% to 50%, and the reflux ratio of the nitrification liquid reflux pipeline 23 is 200% to 300%. Since a small amount of nitrate nitrogen will be produced during the anaerobic ammonia oxidation reaction process, the residual nitrate nitrogen will increase the concentration of total nitrogen. Therefore, the nitrification liquid reflux is realized through the nitrification liquid reflux pipeline 23, and the generated nitrate nitrogen is refluxed to the front stage of the process for treatment, which can reduce the nitrate nitrogen content in the system, thereby ensuring that the final effluent water quality meets the standard.

[0108] When the reflux ratio of the nitrification liquid reflux pipeline 23 is set too low, the total nitrogen in the effluent of the effluent pipeline 22 will exceed the standard, that is, the water quality of the final effluent of the system does not meet the discharge standard; when the reflux ratio is too high, on the one hand, more dissolved oxygen (DO) will be carried, which is easy to destroy the anoxic environment of the anoxic tank, and the denitrification efficiency is difficult to be effectively improved. Therefore, in this application, the reflux ratio of the nitrification liquid reflux pipeline 23 is set to 200% to 300%, which can ensure the effective removal of nitrate nitrogen without destroying the anoxic environment required by the front-end process. Optionally, the reflux ratio of the nitrification liquid reflux pipeline 23 can be set to 200%, 210%, 220%, 230%, 240%, 250%, 260%, 270%, 280%, 290%, 300%, etc., and can also be set to other values ​​according to actual conditions, without specific limitation. Optionally, the reflux ratio of the nitrification liquid reflux pipe 23 can be controlled according to the concentration of nitrate nitrogen in the outlet water of the outlet pipe 22, or according to the type of wastewater to be treated. For example, when the wastewater to be treated is anaerobic digestion sludge from restaurant kitchen, the reflux ratio of the nitrification liquid reflux pipe 23 can be maintained at 200% to 300%. When the wastewater to be treated is other types of wastewater, it can be set specifically according to the characteristics of the wastewater to be treated, the pollutants contained, etc., without specific limitation.

[0109] In some embodiments, the reflux ratio of the nitrifying liquid reflux pipe 23 = the reflux volume of the nitrifying liquid reflux pipe 23 / the water inlet volume of the water inlet pipe 21. The water inlet volume of the water inlet pipe 21 is usually relatively fixed. Therefore, after the reflux ratio of the nitrifying liquid reflux pipe 23 is determined, the specific reflux volume of the nitrifying liquid reflux pipe 23 can be calculated.

[0110] The reflux ratio of the nitrite liquid reflux pipe 26 can be set according to the operating status of the one-stage anaerobic ammonium oxidation reactor 13. When there is no nitrite nitrogen accumulation in the one-stage anaerobic ammonium oxidation reactor 13 and the denitrification load is lower than the design value, the reflux ratio of the nitrite liquid reflux pipe 26 can be set to 20% to 50% to provide nitrite nitrogen for the one-stage anaerobic ammonium oxidation reactor 13 and promote the anaerobic ammonium oxidation reaction.

[0111] In some embodiments, the reflux ratio of the nitrite liquid reflux pipe 26 = the reflux amount of the nitrite liquid reflux pipe 26 / the water inlet amount of the water inlet pipe 21. The water inlet amount of the water inlet pipe 21 is usually relatively fixed. Therefore, when the reflux ratio of the nitrite liquid reflux pipe 26 is determined, the specific reflux amount of the nitrite liquid reflux pipe 26 can be calculated.

[0112] In some embodiments, valves are provided on the first bypass pipe 24, the second bypass pipe 25, the nitrite liquid reflux pipe 26 and the nitrate liquid reflux pipe 23, and the corresponding pipes are opened or closed and the flow rate of the corresponding pipes is controlled by the valves.

[0113] In some embodiments, in the one-stage anaerobic ammonium oxidation reactor 13, the dissolved oxygen is maintained in the range of 0.1 to 0.6 mg / L by controlling the aeration rate, providing an aerobic environment for ammonia oxidizing bacteria, thereby achieving nitrite nitrogen generation by nitrite reaction in the one-stage anaerobic ammonium oxidation reactor 13. Optionally, the concentration of dissolved oxygen can be 0.1 mg / L, 0.2 mg / L, 0.3 mg / L, 0.4 mg / L, 0.5 mg / L, 0.6 mg / L, and can also be set to other concentrations or other concentration ranges according to actual conditions, without specific limitation.

[0114] A wastewater treatment system of the present application has three operating strategies, namely a first strategy for removing ammonia nitrogen, a second strategy for removing nitrite nitrogen, and a third strategy activated when the effluent meets the standard. When the system is used to treat the wastewater to be treated, especially when treating high-ammonia nitrogen and high-organic wastewater, the specific strategy of the system operation is determined according to the total nitrogen concentration, ammonia nitrogen concentration and nitrite nitrogen concentration of the effluent of the one-stage anaerobic ammonium oxidation reactor 13. When both the total nitrogen and ammonia nitrogen exceed the standard, the first strategy is activated to further remove ammonia nitrogen. When the total nitrogen and nitrite nitrogen exceed the standard, the second strategy is activated to remove nitrite nitrogen. When the total nitrogen meets the emission standard, the third strategy is directly activated, thereby effectively removing the ammonia nitrogen and nitrite nitrogen in the effluent of the one-stage anaerobic ammonium oxidation reactor 13 and improving the removal rate of the total nitrogen. At the same time, a nitrification liquid reflux pipeline 23 is also provided to realize the reflux of the nitrification liquid, so that the nitrate nitrogen generated by the anaerobic ammonia oxidation reaction can be refluxed through the nitrification liquid reflux pipeline 23 to the anoxic tank of the high-load carbonization / denitrification reaction tank 11 for denitrification and denitrification, further improving the removal rate of total nitrogen and ensuring that the final effluent water quality meets the standard. When the system and method of the present application are used to treat wastewater, the nitrogen removal efficiency is high, and the unstable effluent water quality caused by unstable aeration control or other reasons in the one-stage anaerobic ammonia oxidation reactor 13 can be effectively dealt with, and the nitrate nitrogen generated by the anaerobic ammonia oxidation reaction can be effectively removed to avoid the problem of the final effluent total nitrogen not meeting the standard due to the accumulation of nitrate nitrogen; at the same time, the system and method do not need to strictly control the aeration volume, the complexity is low, easy to control and implement, and do not need to be connected to the deep treatment process section, and do not need to add additional carbon source, the treatment cost is effectively reduced, which is conducive to practical application and promotion on site.

[0115] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0116] In addition, when details are set forth to describe exemplary embodiments of the present application, it is obvious to those skilled in the art that the present application embodiments can be implemented without these details or with changes in these details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0117] For simplifying explanation and discussion, and in order not to make the embodiment of the present application difficult to understand, the known power supply / ground connection with other parts may or may not be shown in the provided drawings. In addition, the device can be shown in the form of a block diagram to avoid making the embodiment of the present application difficult to understand, and this also takes into account the following fact, that is, the details of the implementation method of these block diagram devices are highly dependent on the platform to be implemented in the embodiment of the present application (that is, these details should be completely within the scope of understanding of those skilled in the art). In the case of elaborating specific details to describe the exemplary embodiments of the present application, it is obvious to those skilled in the art that the embodiment of the present application can be implemented without these specific details or when these specific details are changed. Therefore, these descriptions should be considered to be illustrative rather than restrictive.

[0118] Although the present application has been described in conjunction with the specific embodiments of the present application, many replacements, modifications and variations of these embodiments will be apparent to those of ordinary skill in the art based on the foregoing description. The present application embodiments are intended to encompass all such replacements, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application embodiments should be included in the protection scope of the present application.

Claims

1. A wastewater treatment system, characterized in that: include: A high-load carbonization / denitrification reaction tank, a secondary sedimentation tank, a one-stage anaerobic ammonium oxidation reactor, a nitrite reactor and an anaerobic ammonium oxidation reactor are connected in sequence through pipelines; A water inlet pipe connected to the water inlet of the high-load carbonization / denitrification reaction tank, used to guide the wastewater to be treated into the high-load carbonization / denitrification reaction tank for treatment; A water outlet pipe connected to the water outlet of the anaerobic ammonium oxidation reactor, used to discharge the treated wastewater out of the system; A nitrification liquid reflux pipeline connecting the effluent pipeline and the high-load carbonization / denitrification reaction tank is used to reflux part of the effluent from the effluent pipeline to the high-load carbonization / denitrification reaction tank; A first bypass pipe connecting the one-stage anaerobic ammonium oxidation reactor and the one-stage anaerobic ammonium oxidation reactor is used to guide the effluent of the one-stage anaerobic ammonium oxidation reactor into the one-stage anaerobic ammonium oxidation reactor; A second bypass pipe connecting the one-stage anaerobic ammonium oxidation reactor and the outlet pipe, for guiding the outlet water of the one-stage anaerobic ammonium oxidation reactor into the outlet pipe; A segmented water inlet pipe connecting the secondary sedimentation tank and the anaerobic ammonium oxidation reactor is used to guide part of the effluent from the secondary sedimentation tank into the anaerobic ammonium oxidation reactor.

2. A wastewater treatment system according to claim 1, characterized in that: Also includes: A nitrite liquid reflux pipeline connecting the nitrite reactor and the one-stage anaerobic ammonium oxidation reactor is used to reflux part of the effluent from the nitrite reactor to the one-stage anaerobic ammonium oxidation reactor.

3. A wastewater treatment system according to claim 1, characterized in that: The high-load carbonization / denitrification reaction tank includes an anoxic tank for realizing denitrification reaction and an aerobic tank for degrading organic matter. The anoxic tank, the aerobic tank and the secondary sedimentation tank are connected in sequence through pipelines. The water inlet of the anoxic tank is connected to the water inlet pipeline; the nitrification liquid reflux pipeline is connected to the anoxic tank to return part of the effluent from the effluent pipeline to the anoxic tank.

4. A method for treating wastewater, characterized in that: A wastewater treatment system according to any one of claims 1 to 3, comprising: Obtaining the total nitrogen concentration, ammonia nitrogen concentration and nitrite nitrogen concentration of the effluent from the one-stage anaerobic ammonium oxidation reactor; In response to determining that the total nitrogen concentration is greater than or equal to a first threshold and the ammonia nitrogen concentration is greater than or equal to a second threshold, enabling a first strategy; The first strategy includes: Closing the first override pipe and the second override pipe; The nitrite reactor and the anaerobic ammonium oxidation reactor are connected and activated, and the effluent of the one-stage anaerobic ammonium oxidation reactor is sequentially passed into the nitrite reactor and the anaerobic ammonium oxidation reactor for treatment; The nitrification liquid reflux pipe and the effluent pipe are connected, and the effluent of the anaerobic ammonium oxidation reactor is passed into the effluent pipe, part of the effluent in the effluent pipe is refluxed to the high-load carbonization / denitrification reaction tank through the nitrification liquid reflux pipe for further treatment, and the other part is directly discharged from the system; In response to determining that the total nitrogen concentration is greater than or equal to a first threshold and the nitrite nitrogen concentration is greater than or equal to a third threshold, enabling a second strategy; The second strategy includes: Closing the nitrification reactor and the second bypass pipe; Activating the anaerobic ammonium oxidation reactor and connecting it to the first bypass pipe to pass the effluent of the one-stage anaerobic ammonium oxidation reactor into the anaerobic ammonium oxidation reactor for treatment; The nitrification liquid reflux pipeline and the outlet pipeline are connected to pass the outlet water of the anaerobic ammonia oxidation reactor into the outlet pipeline, part of the outlet water of the outlet pipeline is refluxed to the high-load carbonization / denitrification reaction tank through the nitrification liquid reflux pipeline for further treatment, and the other part is directly discharged from the system; In response to determining that the total nitrogen concentration is less than a first threshold, enabling a third strategy; The third strategy includes: Closing the nitrite reactor, the anaerobic ammonium oxidation reactor and the first bypass pipeline; The second bypass pipe, the nitrification liquid reflux pipe and the outlet pipe are connected to directly pass the effluent of the one-stage anaerobic ammonia oxidation reactor into the outlet pipe, part of the effluent from the outlet pipe is refluxed to the high-load carbonization / denitrification reaction tank through the nitrification liquid reflux pipe for further treatment, and the other part is directly discharged from the system.

5. A wastewater treatment method according to claim 4, characterized in that: The first strategy and the second strategy also include: Connecting the segmented water inlet pipe to guide part of the effluent from the secondary sedimentation tank into the anaerobic ammonium oxidation reactor; The third strategy also includes: closing the segmented water inlet pipeline; And / or, the first strategy further includes: Connecting the nitrite liquid reflux pipeline, returning part of the effluent from the nitrite reactor to the one-stage anaerobic ammonium oxidation reactor through the nitrite liquid reflux pipeline, and passing another part of the effluent into the anaerobic ammonium oxidation reactor for further treatment; The second strategy and the third strategy also include: closing the nitrite liquid reflux pipeline.

6. A wastewater treatment method according to claim 5, characterized in that: The flow rate of the segmented water inlet pipe in the first strategy is calculated by the following formula: Q0 = 0.76Q1*C1 / C2; The flow rate of the segmented water inlet pipe in the second strategy is calculated by the following formula: Q0 = 0.76Q2*C3 / C2; Among them, Q0 is the flow rate of the segmented water inlet pipe, Q1 is the total effluent flow of the nitrite reactor, C1 is the nitrite nitrogen concentration of the effluent of the nitrite reactor, and C2 is the ammonia nitrogen concentration of the effluent of the secondary sedimentation tank; Q2 is the total effluent flow of the one-stage anaerobic ammonium oxidation reactor, and C3 is the nitrite nitrogen concentration of the effluent of the one-stage anaerobic ammonium oxidation reactor.

7. A wastewater treatment method according to claim 4, characterized in that: The first threshold is 70 mg / L, the second threshold is 45 mg / L, and the third threshold is 50 mg / L.

8. A wastewater treatment method according to claim 5, characterized in that: The reflux ratio of the nitrite liquid reflux pipeline is 20% to 50%, and the reflux ratio of the nitrate liquid reflux pipeline is 200% to 300%.

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