Accurate control system and control device for efficient denitrification of sewage

Abstract

According to the precise control system and device for efficient denitrification of sewage, high-dissolved-oxygen aeration is adopted at the aerobic front end of an aerobic section, medium-degree aeration is adopted at the aerobic middle section, low-dissolved-oxygen aeration is adopted at the aerobic tail end of the aerobic section, and phosphorus-accumulating bacteria are promoted to absorb phosphorus and release carbon through high-dissolved-oxygen aeration at the aerobic front end; and the released carbon source is a high-quality carbon source which is easily utilized by denitrifying bacteria. The aerobic middle section and the aerobic tail section gradually reduce dissolved oxygen, so that synchronous denitrification can be realized on the premise of ensuring effective nitrification of ammonia nitrogen, and the denitrification effect is improved. According to the invention, real-time monitoring of ammonia nitrogen, nitrate nitrogen and dissolved oxygen is adopted, according to the treatment requirement and the residence time, fitting is carried out on the linear valve opening degree and the dissolved oxygen content, effective dissolved oxygen control is realized by controlling the valve opening degree, and regression calculation is further carried out on monitoring data fed back in real time through an intelligent control module, so that the monitoring accuracy is improved. And the dissolved oxygen content in different stages is accurately controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of precise sewage control, and in particular to a precise control system and a control device for efficient sewage denitrification. Background Art

[0002] At present, the mainstream method of sewage treatment relies on biochemical reactions, using the metabolic characteristics of different types of microorganisms to degrade and remove organic matter, nitrogen, phosphorus and other pollutants in sewage. This method of using biological metabolic characteristics to remove pollutants in sewage is called the "activated sludge" method. There are two extremely important control indicators in the activated sludge method: aeration volume and nitrification liquid reflux volume. The purpose of aeration is to provide aerobic bacteria (nitrite bacteria, nitrifying bacteria) with sufficient dissolved oxygen so that they can degrade ammonia nitrogen in the mixed solution into nitrate nitrogen. The purpose of nitrification liquid reflux is to transport the generated nitrate nitrogen to the anoxic zone and use denitrifying bacteria to degrade it into nitrogen gas escape, thereby achieving the purpose of denitrification.

[0003] The aeration operation mode of existing sewage treatment plants is rough, that is, maintaining a high dissolved oxygen (DO) concentration in the aerobic tank to ensure the effective removal of ammonia nitrogen. This aeration method has high energy consumption and is prone to cause a decrease in the denitrification effect in the anoxic zone. On the one hand, this is because the nitrification liquid carries a high DO during the reflux process, which destroys the anoxic environment; on the other hand, aerobic bacteria produce acid under high DO conditions, resulting in the pH of the refluxed nitrification liquid being acidic, affecting the denitrification effect. Subsequently, in order to ensure the denitrification effect, carbon sources were added again, which increased the consumption of reagents and the risk of filamentous bacteria expansion. The phenomenon of filamentous bacteria expansion frequently occurs in most sewage treatment plants, especially in low temperature seasons. In addition, studies have shown that low DO can produce a simultaneous nitrification and denitrification (SND) effect while ensuring the removal of ammonia nitrogen.

[0004] In addition, a large number of technologies for low dissolved oxygen precision aeration have been proposed, but the following problems exist in practical applications:

[0005] (1) The models and control logic used are complex, and the water quality, water quantity, climate, etc. of each water plant are different, so problems often occur during the regulation process.

[0006] (2) Only the terminal ammonia nitrogen and DO indicators are used to control aeration, which is not coordinated with anoxic denitrification and the denitrification effect is not ideal.

[0007] (3) Only the difference between the design range and the actual value is used for regulation, which makes it impossible to make corresponding adjustments based on water quality fluctuations and is difficult to cope with emergencies.

[0008] (4) Low dissolved oxygen produces simultaneous nitrification and denitrification, the nitrate nitrogen content at the aerobic end decreases, and the nitrification liquid reflux cannot be accurately controlled. Summary of the invention

[0009] The object of the present invention is to provide.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] A precise control device for efficient denitrification of sewage, comprising a water inlet, an ammoniation section, an anaerobic section, an anoxic section, an aerobic section and a sedimentation tank connected in sequence;

[0012] The water inlet end is connected to the ammoniation section, and the ammoniation section includes a front-stage organic nitrogen ammoniation module, and the organic nitrogen is converted into ammonia nitrogen through ammoniation; a first ammonia nitrogen detection point and a first nitric nitrogen detection point are provided between the ammoniation section and the anaerobic section, which are used to monitor the concentrations of ammonia nitrogen and nitric nitrogen after the ammoniation section, and feed back to the PLC control system to control the reflux flow of the nitrification liquid to ensure the ammoniation effect;

[0013] The anaerobic section includes an anaerobic treatment module, which is used to promote the release of phosphorus by polyphosphate bacteria by absorbing organic matter under an anaerobic environment, and then release high-quality carbon sources by absorbing excessive phosphorus at the aerobic front end, thereby providing suitable conditions for simultaneous nitrification and denitrification while removing phosphorus;

[0014] The anoxic section includes an anoxic treatment module, which provides nitric nitrogen by refluxing nitrification liquid, and uses a carbon source to perform denitrification under anoxic conditions to generate nitrogen gas for denitrification;

[0015] The aerobic section is refluxed to the anoxic section through a nitrification liquid reflux pump via a pipeline. The nitrification liquid produced in the aerobic section contains a large amount of nitrate nitrogen, which is refluxed to the anoxic section through the nitrification liquid reflux pump to provide the anoxic section with electron acceptor nitrate nitrogen required for denitrification;

[0016] The outlet end of the aerobic section is connected to the sedimentation tank. A dissolved oxygen detection point, an ammonia nitrogen detection point and an aeration mechanism are provided in the aerobic section. The dissolved oxygen detection point and the ammonia nitrogen detection point are used to detect the dissolved oxygen content and the ammonia nitrogen nitrification effect, respectively, and feed back to the PLC control system. The PLC control system controls the aeration mechanism to adjust the aeration amount in the aerobic section through an external blower based on the detection data and a preset threshold value to ensure sufficient nitrification reaction.

[0017] Preferably, the aerobic section includes an aerobic pool front section, an aerobic pool middle section and an aerobic pool end section, and the outlet end of the aerobic end section is connected to a sedimentation tank;

[0018] The front section of the aerobic pool, the middle section of the aerobic pool and the end section of the aerobic pool are all provided with aeration mechanisms with valve control;

[0019] The aerobic pool front section, the aerobic pool middle section and the aerobic pool end section are respectively provided with a first dissolved oxygen detection point, a second dissolved oxygen detection point and a third dissolved oxygen detection point, which are used to detect the dissolved oxygen content of the current aerobic section and feed back to the PLC control system;

[0020] The middle section of the aerobic pool and the end section of the aerobic pool are respectively provided with a second ammonia nitrogen detection point and a third ammonia nitrogen detection point, which are used to detect the ammonia nitrogen nitrification effect of the current aerobic section; the outlet end of the aerobic end is provided with a fourth ammonia nitrogen detection point, which is used to detect the ammonia nitrogen content in the outlet water;

[0021] The detection data obtained from the second ammonia nitrogen detection point, the third ammonia nitrogen detection point and the fourth ammonia nitrogen detection point are fed back to the PLC control system, and the aeration mechanism is controlled to adjust the aeration amount of the previous aerobic section according to a preset threshold value;

[0022] A third nitric nitrogen detection point is provided in the end section of the aerobic pool, which is used to detect the nitric nitrogen content in the reflux nitrification liquid and the mixed liquid transported to the sedimentation tank, and is used to control the dissolved oxygen in the aerobic end section and the reflux flow rate of the nitrification liquid according to the nitric nitrogen concentration in the reflux nitrification liquid;

[0023] And feed back to the PLC control system, and control the aeration mechanism to adjust the aeration volume of the aerobic end stage according to the preset threshold value to ensure the synchronous nitrification and denitrification of the aerobic end stage.

[0024] Preferably, a second nitrate nitrogen detection point is provided after the anoxic section, which is used to determine the nitrate nitrogen content after the anoxic section and feed it back to the PLC control system. The PLC control system dynamically adjusts the nitrification liquid reflux ratio operating parameters according to the detection data to ensure the denitrification balance of the system;

[0025] The detection data of the first nitrate nitrogen detection point and the third nitrate nitrogen detection point are coordinated to calculate the denitrification efficiency coefficient of the anoxic section by comparing the change of nitrate nitrogen concentration.

[0026] Preferably, the sludge separated from the sedimentation tank is transported by a sludge return pump and returned to the anaerobic section through a pipeline to provide high-concentration biomass for the treatment process of the anaerobic section.

[0027] Preferably, flow meters are provided on the pipe connecting the water inlet end and the ammoniation section, on the pipe connecting the aerobic section and the anoxic section, and on the pipe connecting the sedimentation tank and the anaerobic section for statistical real-time monitoring of flow data.

[0028] Preferably, the front section of the aerobic pool is defined as a high dissolved oxygen ammonia nitrogen nitrification section, DO 1 The range is >2mg / L. The middle section of the aerobic pool is defined as the moderate DO transition control section. 2 The range is 0.8mg / L~2mg / L; the aerobic end is defined as the low DO synchronous nitrification and denitrification stage, DO 3 The range is 0~1.0mg / L.

[0029] The present invention also provides a precise control system for efficient denitrification of sewage, comprising an information acquisition module, a parameter conversion module and an intelligent control module;

[0030] The information collection module includes collecting tank capacity data, flow data, detection data and valve opening data;

[0031] The parameter conversion module is used to perform mathematical modeling and function fitting on the real-time data provided by the information acquisition module, so as to provide an accurate adjustment basis for the intelligent control module;

[0032] The intelligent control module includes dissolved oxygen control in the aerobic tank and nitrification liquid reflux control.

[0033] Preferably, the cell capacity data includes V 1 : Anaerobic tank capacity, V 2 : Anoxic section pool capacity, V 3 : Aerobic front section tank capacity, V 4 : Aerobic middle tank volume and V 5 : Aerobic terminal tank capacity;

[0034] Traffic data includes Q 1 : water inlet flow; Q 2 : sludge return flow; Q 3 : nitration liquid reflux flow rate;

[0035] Test data include [NO 3 -N] 1 : Data of the first nitrate detection point; [NO 3 -N] 2 : Data of the second nitrate detection point; [NO 3 -N] 3 : Data of the third nitrate detection point; [NH 3 -N] 1 : Data of the first ammonia nitrogen detection point; [NH 3 -N] 2 : Data of the second ammonia nitrogen detection point; [NH 3 -N] 3 : Data of the third ammonia nitrogen detection point; [NH 3 -N] 4 : Data of the fourth ammonia nitrogen detection point; [DO] 1 : The first dissolved oxygen detection data; [DO] 2 : The second dissolved oxygen detection data; [DO] 3 : The third dissolved oxygen detection data;

[0036] Valve opening data includes FM 1 : Aeration valve 1 data; FM 2 : Aeration valve 2 data; FM 3 : Aeration valve 3 data; FM 4 : Aeration valve 4 data.

[0037] Preferably, the dissolved oxygen control in the aerobic pool includes the front section of the aerobic pool, the middle section of the aerobic pool and the end section of the aerobic pool;

[0038] The front section of the aerobic pool: collect V 1 , V 2 ,,Q 1 , Q 2 , Q 3 , [NH 3 -N] 1 , [NH 3 -N] 2 , [DO] 1 and FM 4 The detection data is initially calculated as follows:

[0039] △ 1 =[NH 3 -N] 1 -[NH 3 -N] 2 ;

[0040] Fitting 1 About [DO] 1 The function △1=f([DO] 1 ), synchronous fitting [DO] 1 About FM 4 Function [DO] 1 =f(FM 4 ), merged into △ 1 =f(FM 4 ), each test data is recorded, screened, and counted. As the data increases, 1 =f(FM 4 ) function is further improved to obtain the inverse function FM that conforms to the actual operation 4 =f(△ 1 );

[0041] Set [NH 3 -N] 2设 Value, calculate △ 1设 =[NH 3 -N] 1 -[NH 3 -N] 2设 ;

[0042] According to △ 1设 The calculated value is obtained by using the function FM 4 =f(△ 1 ) Adjust the opening of the aeration valve ④, and adjust the time delay to [NH 3 -N] 1 The detection time, the delay time is the calculated HRT [NH3-N]1-[NO3-N]2 ;

[0043] HRT [NH3-N]1-[NO3-N]2 =V 1 / (Q 1 +Q 2 )+V 2 / (Q 1 +Q 2 +Q 3 );

[0044] If there is [NH 3 -N] 2 The test data is higher than [NH 3 -N] 2设定 , then increase the aeration valve ④ opening, and adjust the opening in the same way as FM 4 =f(△ 1 ) function, the independent variable is the test data [NH 3 -N] 2 With the setting value [NH 3 -N] 2设定 The difference between

[0045] The middle section of the aerobic pool: collect [NH 3 -N] 2 , [NH 3 -N] 3 , [DO] 2 and FM 3 The detection data is initially calculated as follows:

[0046] △ 2 =[NH 3 -N] 2 -[NH 3 -N] 3 ;

[0047] Fitting 2 About [DO] 2 The function △2=f([DO] 2 ), synchronous fitting [DO] 2 About FM 3 Function [DO] 2 =f(FM 3 ), merged into △ 2 =f(FM 3 ), each test data is recorded, screened, and counted. As the data increases, 2 =f(FM 3 ) function is further improved to obtain the inverse function FM that conforms to the actual operation 3 =f(△ 2 ); Set [NH 3 -N] 3设 The value is calculated as follows:

[0048] △ 2设 =[NH 3 -N] 2 -[NH 3 -N] 3设 ;

[0049] According to △ 2设 The calculated value is obtained by using the function FM 3 =f(△ 2 ) Adjust the opening of the aeration valve ③, and the adjustment time is the same as [NH 3 -N] 2 Detection time; if there is [NH 3 -N] 3 The test data is higher than [NH 3 -N] 3设 , then increase the aeration valve ③ opening, adjust the opening to FM 3 =f(△ 2 ) function, the independent variable is the test data [NH 3 -N] 3 With the setting value [NH 3 -N] 3设 The difference between

[0050] The last section of the aerobic pool: collect V 3 ,V 4 ,Q 1 , Q 2 , Q 3 , [NO 3 -N] 2 , [NO 3 -N] 3 , [NH 3 -N] 1 , [NH 3 -N] 3 , [DO] 3 and FM 2 The detection data is initially calculated as follows:

[0051] △ 3 =[NO 3 -N] 2 +([NH 3 -N] 1 )×Q 1 / (Q 1 +Q 2 +Q 3 )-[NH 3 -N] 3 -[NO 3 -N] 3 ;

[0052] Fitting 3About [DO] 3 The function △3=f([DO] 3 ), synchronous fitting [DO] 3 About FM 2 Function [DO] 3 =f(FM 2 ), merged into △ 3 =f(FM 2 ), each test data is recorded, screened, and counted. As the data increases, 3 =f(FM 2 ) function is further improved to obtain the inverse function FM that conforms to the actual operation 2 =f(△ 3 );

[0053] Set [NO 3 -N] 3设 The value is calculated as follows:

[0054] △ 3设 =[NO 3 -N] 2 +([NH 3 -N] 1 )×Q 1 / (Q 1 +Q 2 +Q 3 )-[NH 3 -N] 3设 -[NO 3 -N] 3设 ;

[0055] According to △ 3设 Calculated value by FM 2 =f(△ 3 ) Adjust the opening of the aeration valve ②, and adjust the time delay to [NO 3 -N] 2 The detection time, the delay time is the calculated HRT [NO3-N]2-[NO3-N]3 ;

[0056] HRT [NO3-N]2-[NO3-N]3 =(V 3 +V 4 ) / (Q 1 +Q 2 +Q 3 );

[0057] If there is [NO 3 -N] 3 The test data is higher than [NO 3 -N] 3设 , then reduce the aeration valve ② opening, adjust the opening feedback to correct FM 2 =f(△3 )function;

[0058] If the valves in the front and middle sections of the aerobic pool have been opened to the maximum, [NH 3 -N] 4 If it is still higher than the set value, increase the opening of the aeration valve ②. If [NO 3 -N] 3 and [NH 3 -N] 4 If the value is higher than the set value, set the priority processing object according to actual needs.

[0059] Preferably, the nitrification liquid reflux control includes the following steps:

[0060] When the dissolved oxygen control regulation in the aerobic tank fails to reduce [NO 3 -N] 3 When the nitration liquid reflux rate is adjusted, the adjustment method is as follows:

[0061] Collect Q 1 , Q 2 , Q 3 , [NO 3 -N] 1 , [NO 3 -N] 2 and [NO 3 -N] 3 The detection data is initially calculated as follows:

[0062] △ 4 =([NO 3 -N] 1 ×Q 1 +[NO 3 -N] 3 ×(Q 2 +Q 3 )) / (Q 1 +Q 2 +Q 3 )-[NO 3 -N] 2 ;

[0063] Fitting 4 About Q 3 Function of △ 4 =f(Q 3 ), each test data is recorded, screened, and counted. As the data increases, 4 =f(Q 3 ) function is further improved to obtain the inverse function Q that conforms to the actual operation 3 =f(△ 4 );

[0064] Set [NO3 -N] 3设 The value is calculated as follows:

[0065] △ 4设 =([NO 3 -N] 1 ×Q 1 +[NO 3 -N] 3设 ×(Q 2 +Q 3 )) / (Q 1 +Q 2 +Q 3 )-[NO 3 -N] 2 ;

[0066] Derivation of Q 3 ={△ 4设 -Q 1 ×([NO 3 -N] 1 -[NO 3 -N] 2 )} / ([NO 3 -N] 3设 -[NO 3 -N] 2 )-Q 2 ;

[0067] According to △ 4设 The calculated value is Q 3 =f(△ 4 )Adjust the reflux flow rate of nitrification solution.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] (1) The aerobic section of the present invention adopts a new aeration control method, with high dissolved oxygen aeration at the front end, medium aeration in the middle section, and low dissolved oxygen aeration at the end. High dissolved oxygen aeration at the front end promotes phosphorus accumulation bacteria to absorb phosphorus and release carbon, and the released carbon source is a high-quality carbon source that is easily utilized by denitrifying bacteria. The dissolved oxygen is gradually reduced in the middle section and the end section, which can achieve synchronous denitrification while ensuring effective nitrification of ammonia nitrogen, thereby improving the denitrification effect.

[0070] (2) The present invention uses real-time monitoring of ammonia nitrogen, nitric nitrogen and dissolved oxygen. According to the treatment requirements and the residence time, the monitoring data fed back in real time is regressed through the intelligent control module to accurately control the dissolved oxygen content at different stages, and further fit the linear valve opening and the dissolved oxygen content, and realize effective dissolved oxygen control by controlling the valve opening. With the increase of operation time and the continuous accumulation of monitoring data, the fitted equation of the control method of the present invention will be more in line with the actual operation situation, and the control effect will be more accurate. The control method of the present invention can formulate a dissolved oxygen control strategy in advance in combination with the incoming water quality and the treatment target, and effectively deal with sudden water quality situations.

[0071] (3) The present invention coordinates the nitrification liquid return rate with the inlet and outlet water quality, and can adjust the nitrification liquid return rate according to the actual monitoring water quality coordinated treatment target requirements.

[0072] (4) The control system of the present invention is combined with the whole process nitrogen form conversion, which conforms to the denitrification mechanism, does not require a fixed model, has simple control logic and a wide range of applications.

[0073] (5) The control system of the present invention combines ammonia nitrogen, nitric nitrogen, dissolved oxygen and nitrification liquid reflux, and coordinates anoxic denitrification to effectively achieve the removal of total nitrogen under the premise of removing ammonia nitrogen.

[0074] (6) The control system of the present invention, under the premise of designing the dissolved oxygen value and the nitrification liquid reflux range, derives and calculates the required dissolved oxygen value through the actual monitoring values ​​and residence time of different sections, effectively coping with water quality shocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 A schematic structural diagram of a precise control system and control device for efficient denitrification of sewage provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0078] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0079] like Figure 1 As shown, a precise control system and control device for efficient denitrification of sewage provided in this embodiment include a water inlet, an ammoniation section, an anaerobic section, an anoxic section, an aerobic section and a sedimentation tank connected in sequence.

[0080] The water inlet is connected to the ammoniation section, which includes a front-end organic nitrogen ammoniation module, and the organic nitrogen is converted into ammonia nitrogen through ammoniation. A first ammonia nitrogen detection point and a first nitric nitrogen detection point are arranged between the ammoniation section and the anaerobic section.

[0081] The first ammonia nitrogen detection point is set after the ammoniation section to determine the ammonia nitrogen content after the ammoniation section and feed it back to the PLC control system. It cooperates with the second ammonia nitrogen detection point to calculate and analyze the conversion efficiency of ammonia nitrogen in the front section of the aerobic tank, and cooperates with the first nitric nitrogen detection point to control the nitrification liquid reflux flow rate.

[0082] The first nitrate nitrogen detection point: The first nitrate nitrogen detection point is set after the ammoniation section to determine the nitrate nitrogen content after the ammoniation section and feed it back to the PLC control system to coordinate with the first ammonia nitrogen detection point to control the nitrification liquid reflux flow rate.

[0083] The anaerobic section includes an anaerobic treatment module, which is used to promote polyphosphate bacteria to absorb organic matter and release phosphorus under an anaerobic environment. Subsequently, the aerobic front end absorbs excessive phosphorus and releases high-quality carbon sources, thereby removing phosphorus and providing suitable conditions for simultaneous nitrification and denitrification.

[0084] The anoxic section includes an anoxic treatment module, which provides nitric nitrogen by refluxing nitrification liquid, and uses carbon sources for denitrification under anoxic conditions to generate nitrogen gas for denitrification.

[0085] The aerobic section is refluxed to the anoxic section via a pipeline through a nitrification liquid reflux pump. The nitrification liquid produced in the aerobic section contains a large amount of nitrate nitrogen, which is refluxed to the anoxic section through the nitrification liquid reflux pump to provide the anoxic section with the electron acceptor nitrate nitrogen required for denitrification.

[0086] The aerobic section includes the front section of the aerobic pool, the middle section of the aerobic pool and the end section of the aerobic pool, and the outlet end of the aerobic end is connected to the sedimentation tank.

[0087] Aeration mechanisms with valve control are provided in the front section, middle section and end section of the aerobic pool. A fourth aeration valve is provided on the aeration pipe in the front section of the aerobic pool, a third aeration valve is provided on the aeration pipe in the middle section of the aerobic pool, and a second aeration valve is provided on the aeration pipe in the end section of the aerobic pool. The aeration pipes are uniformly connected to external blowers, and their overall opening and closing is controlled by the first aeration valve.

[0088] The first dissolved oxygen detection point, the second dissolved oxygen detection point and the third dissolved oxygen detection point are respectively arranged in the front section of the aerobic pool, the middle section of the aerobic pool and the end section of the aerobic pool.

[0089] The front section of the aerobic pool is a high dissolved oxygen zone, which aims to stimulate the activity of aerobic microorganisms, increase the rate of nitrification reaction, and ensure the release of high-quality carbon sources by aerobic phosphorus absorption, providing favorable conditions for subsequent synchronous nitrification and denitrification. The first dissolved oxygen detection point is set in the front section of the aerobic pool to detect the dissolved oxygen content in the first section of the aerobic zone. The DO in the front section of the aerobic pool is controlled by the fourth aeration valve. 1 The range is >2mg / L.

[0090] The middle section of the aerobic pool is a controlled transition zone. Its purpose is to ensure that most of the ammonia nitrogen has been completely nitrified after high dissolved oxygen aeration, and the remaining small amount of ammonia nitrogen is gradually nitrified under moderate dissolved oxygen conditions, while the transition produces simultaneous nitrification and denitrification conditions. The second dissolved oxygen detection point is set in the middle section of the aerobic pool to detect the dissolved oxygen content in the second section of the aerobic zone. It is controlled by the third aeration valve to ensure the DO in the middle section of the aerobic pool. 2 The range is 0.8mg / L~2mg / L.

[0091] The aerobic end is a synchronous nitrification and denitrification area. While ammonia nitrogen is nitrified, nitrate nitrogen is partially denitrified. The third dissolved oxygen detection point is set at the aerobic end to detect the dissolved oxygen content at the aerobic end. It is controlled by the second aeration valve to ensure the DO in the aerobic end. 3 The range is 0~1.0mg / L.

[0092] The second ammonia nitrogen detection point and the third ammonia nitrogen detection point are respectively set in the middle section of the aerobic pool and the end section of the aerobic pool. Among them, the second ammonia nitrogen detection point is set in the front section of the middle section of the aerobic pool. The second ammonia nitrogen detection point and the first ammonia nitrogen detection point jointly calculate and analyze the ammonia nitrogen nitrification effect in the front section of the aerobic pool, and feed it back to the PLC control system. According to the value measured by the second ammonia nitrogen detection point, the fourth aeration valve in the front section of the aerobic pool is controlled to ensure sufficient nitrification reaction in the front section of the aerobic pool. Design scope: When the detection data of ammonia nitrogen detection point 2 is greater than the set value, the opening of the fourth aeration valve in the front section of the aerobic pool is increased.

[0093] The third ammonia nitrogen detection point is set at the front of the last section of the aerobic pool. This point detects the nitrification effect of ammonia nitrogen in the middle section of the aerobic pool and feeds back to the PLC control system. The third aeration valve in the middle section of the aerobic pool is controlled according to the value measured by the third ammonia nitrogen detection point to ensure sufficient nitrification reaction in the middle section of the aerobic pool. Design scope: When the detection data of ammonia nitrogen detection point 3 is greater than the set value, the opening of the third aeration valve in the middle section of the aerobic pool is increased.

[0094] The fourth ammonia nitrogen detection point is set at the outlet of the aerobic end. The fourth ammonia nitrogen detection point detects the ammonia nitrogen content in the water and feeds back to the PLC control system. According to the value of the fourth ammonia nitrogen detection point, the second aeration valve in the end of the aerobic pool is controlled to ensure that the ammonia nitrogen in the effluent meets the standard. Design scope: When the detection data of ammonia nitrogen detection point 4> set value, increase the opening of the second aeration valve in the end of the aerobic pool. If there is a conflict between the fourth ammonia nitrogen detection point and the third nitrate nitrogen detection point, the control procedure of the fourth ammonia nitrogen detection point shall be implemented first.

[0095] A third nitrate nitrogen detection point is also provided in the last section of the aerobic tank, which is used to detect the nitrate nitrogen content in the reflux nitrification liquid and the mixed liquid transported to the sedimentation tank, and is used to control the dissolved oxygen and nitrification liquid reflux flow rate in the aerobic last section according to the nitrate nitrogen concentration in the reflux nitrification liquid; and feedback is given to the PLC control system, and the opening of the second aeration valve in the aerobic last section is controlled according to the preset threshold value, and the aeration volume is adjusted to ensure simultaneous nitrification and denitrification in the aerobic last section. Design scope: When the detection value of the third nitrate nitrogen detection point is greater than the set value, the opening of the second aeration valve in the last section of the aerobic tank is reduced. If there is a conflict between the third nitrate nitrogen detection and the fourth ammonia nitrogen detection point control, the fourth ammonia nitrogen detection point control shall be implemented first.

[0096] Furthermore, in this embodiment, a second nitrate nitrogen detection point is provided after the anoxic section, which is used to determine the nitrate nitrogen content after the anoxic section and to feed back to the PLC control system, in coordination with the detection data measured by the first nitrate nitrogen detection point and the third nitrate nitrogen detection point. The PLC control system dynamically adjusts the nitrification liquid reflux ratio operating parameters through the detection data to ensure the denitrification balance of the system;

[0097] Furthermore, in this embodiment, the sludge separated in the sedimentation tank is transported by a sludge return pump and returned to the anaerobic section through a pipeline, providing a high concentration of biomass for the treatment process of the anaerobic section.

[0098] The present invention also provides a precise control system based on the above-mentioned efficient sewage denitrification, including an information acquisition module, a parameter conversion module and an intelligent control module.

[0099] The information acquisition module includes the collection of pool capacity data, flow data, detection data and valve opening data. The parameter conversion module is used to perform mathematical modeling and function fitting on the real-time data provided by the information acquisition module, providing an accurate adjustment basis for the intelligent control module. The intelligent control module includes dissolved oxygen control in the aerobic pool and nitrification liquid return flow control.

[0100] Cell capacity data includes V 1 : Anaerobic tank capacity, V 2 : Anoxic section pool capacity, V 3 : Aerobic front section tank capacity, V 4 : Aerobic middle tank volume and V 5 : Aerobic terminal pool capacity.

[0101] Traffic data includes Q 1 : water inlet flow; Q 2 : sludge return flow; Q 3 : Nitration liquid reflux flow rate.

[0102] Test data include [NO 3 -N] 1 : Data of the first nitrate detection point; [NO 3 -N] 2: Data of the second nitrate detection point; [NO 3 -N] 3 : Data of the third nitrate detection point; [NH 3 -N] 1 : Data of the first ammonia nitrogen detection point; [NH 3 -N] 2 : Data of the second ammonia nitrogen detection point; [NH 3 -N] 3 : Data of the third ammonia nitrogen detection point; [NH 3 -N] 4 : Data of the fourth ammonia nitrogen detection point; [DO] 1 : The first dissolved oxygen detection data; [DO] 2 : The second dissolved oxygen detection data; [DO] 3 : The third dissolved oxygen detection data.

[0103] Valve opening data includes FM 1 : Aeration valve 1 data; FM 2 : Aeration valve 2 data; FM 3 : Aeration valve 3 data; FM 4 : Aeration valve 4 data.

[0104] The dissolved oxygen control in the aerobic pool includes the front section, middle section and end section of the aerobic pool;

[0105] Aerobic pool front section: Collect V 1 , V 2 ,,Q 1 , Q 2 , Q 3 , [NH 3 -N] 1 , [NH 3 -N] 2 , [DO] 1 and FM 4 The detection data is initially calculated as follows:

[0106] △ 1 =[NH 3 -N] 1 -[NH 3 -N] 2 ;

[0107] Fitting 1 About [DO] 1 The function △1=f([DO] 1 ), synchronous fitting [DO] 1 About FM 4 Function [DO] 1 =f(FM 4 ), merged into △1 =f(FM 4 ), each test data is recorded, screened, and counted. As the data increases, 1 =f(FM 4 ) function is further improved to obtain the inverse function FM that conforms to the actual operation 4 =f(△ 1 );

[0108] Set [NH 3 -N] 2设 Value, calculate △ 1设 =[NH 3 -N] 1 -[NH 3 -N] 2设 ;

[0109] According to △ 1设 The calculated value is obtained by using the function FM 4 =f(△ 1 ) Adjust the opening of the aeration valve ④, and adjust the time delay to [NH 3 -N] 1 The detection time, the delay time is the calculated HRT [NH3-N]1-[NO3-N]2 ;

[0110] HRT [NH3-N]1-[NO3-N]2 =V 1 / (Q 1 +Q 2 )+V 2 / (Q 1 +Q 2 +Q 3 );

[0111] If there is [NH 3 -N] 2 The test data is higher than [NH 3 -N] 2设定 , then increase the aeration valve ④ opening, and adjust the opening in the same way as FM 4 =f(△ 1 ) function, the independent variable is the test data [NH 3 -N] 2 With the setting value [NH 3 -N] 2设定 The difference between

[0112] Middle section of aerobic pool: Collect [NH 3 -N] 2 , [NH 3 -N] 3 , [DO] 2 and FM 3 The detection data is initially calculated as follows:

[0113] △ 2 =[NH 3 -N] 2 -[NH 3 -N] 3 ;

[0114] Fitting 2 About [DO] 2 The function △2=f([DO] 2 ), synchronous fitting [DO] 2 About FM 3 Function [DO] 2 =f(FM 3 ), merged into △ 2 =f(FM 3 ), each test data is recorded, screened, and counted. As the data increases, 2 =f(FM 3 ) function is further improved to obtain the inverse function FM that conforms to the actual operation 3 =f(△ 2 ); Set [NH 3 -N] 3设 The value is calculated as follows:

[0115] △ 2设 =[NH 3 -N] 2 -[NH 3 -N] 3设 ;

[0116] According to △ 2设 The calculated value is obtained by using the function FM 3 =f(△ 2 ) Adjust the opening of the aeration valve ③, and the adjustment time is the same as [NH 3 -N] 2 Detection time; if there is [NH 3 -N] 3 The test data is higher than [NH 3 -N] 3设 , then increase the aeration valve ③ opening, adjust the opening to FM 3 =f(△ 2 ) function, the independent variable is the test data [NH 3 -N] 3 With the setting value [NH 3 -N] 3设 The difference between

[0117] Aerobic pool end: Collect V 3 ,V 4 ,Q 1 , Q 2 , Q3 , [NO 3 -N] 2 , [NO 3 -N] 3 , [NH 3 -N] 1 , [NH 3 -N] 3 , [DO] 3 and FM 2 The detection data is initially calculated as follows:

[0118] △ 3 =[NO 3 -N] 2 +([NH 3 -N] 1 )×Q 1 / (Q 1 +Q 2 +Q 3 )-[NH 3 -N] 3 -[NO 3 -N] 3 ;

[0119] Fitting 3 About [DO] 3 The function △3=f([DO] 3 ), synchronous fitting [DO] 3 About FM 2 Function [DO] 3 =f(FM 2 ), merged into △ 3 =f(FM 2 ), each test data is recorded, screened, and counted. As the data increases, 3 =f(FM 2 ) function is further improved to obtain the inverse function FM that conforms to the actual operation 2 =f(△ 3 );

[0120] Set [NO 3 -N] 3设 The value is calculated as follows:

[0121] △ 3设 =[NO 3 -N] 2 +([NH 3 -N] 1 )×Q 1 / (Q 1 +Q 2 +Q 3 )-[NH 3 -N]3设 -[NO 3 -N] 3设 ;

[0122] According to △ 3设 Calculated value by FM 2 =f(△ 3 ) Adjust the opening of the aeration valve ②, and adjust the time delay to [NO 3 -N] 2 The detection time, the delay time is the calculated HRT [NO3-N]2-[NO3-N]3 ;

[0123] HRT [NO3-N]2-[NO3-N]3 =(V 3 +V 4 ) / (Q 1 +Q 2 +Q 3 );

[0124] If there is [NO 3 -N] 3 The test data is higher than [NO 3 -N] 3设 , then reduce the aeration valve ② opening, adjust the opening feedback to correct FM 2 =f(△ 3 )function;

[0125] If the valves in the front and middle sections of the aerobic pool have been opened to the maximum, [NH 3 -N] 4 If it is still higher than the set value, increase the opening of the aeration valve ②. If [NO 3 -N] 3 and [NH 3 -N] 4 If the value is higher than the set value, set the priority processing object according to actual needs.

[0126] The nitration liquid reflux control includes the following:

[0127] When the dissolved oxygen control regulation in the aerobic tank cannot reduce [NO 3 -N] 3 When the nitration liquid reflux rate is adjusted, the adjustment method is as follows:

[0128] Collect Q 1 , Q 2 , Q 3 , [NO 3 -N] 1 , [NO 3 -N] 2 and [NO 3 -N] 3 The detection data is initially calculated as follows:

[0129] △ 4 =([NO 3 -N] 1 ×Q 1 +[NO 3 -N] 3 ×(Q 2 +Q 3 )) / (Q 1 +Q 2 +Q 3 )-[NO 3 -N] 2 ;

[0130] Fitting 4 About Q 3 Function of △ 4 =f(Q 3 ), each test data is recorded, screened, and counted. As the data increases, 4 =f(Q 3 ) function is further improved to obtain the inverse function Q that conforms to the actual operation 3 =f(△ 4 );

[0131] Set [NO 3 -N] 3设 The value is calculated as follows:

[0132] △ 4设 =([NO 3 -N] 1 ×Q 1 +[NO 3 -N] 3设 ×(Q 2 +Q 3 )) / (Q 1 +Q 2 +Q 3 )-[NO 3 -N] 2 ;

[0133] Derivation of Q 3 ={△ 4设 -Q 1 ×([NO 3 -N] 1 -[NO 3 -N] 2 )} / ([NO 3 -N] 3设 -[NO 3 -N] 2 )-Q 2 According to △ 4设 The calculated value is Q 3 =f(△4 ) adjust the nitrification solution reflux flow rate. The following test is made in conjunction with the specific embodiment data:

[0134] Test 1

[0135]

[0136] Test 2

[0137]

[0138] Test 3

[0139]

[0140]

[0141] Test 4

[0142]

[0143] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0144] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0145] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A precise control device for efficient denitrification of sewage, characterized in that: It includes a water inlet, an ammoniation section, an anaerobic section, an anoxic section, an aerobic section and a sedimentation tank connected in sequence; The water inlet end is connected to the ammoniation section, and the ammoniation section includes a front-stage organic nitrogen ammoniation module, and the organic nitrogen is converted into ammonia nitrogen through ammoniation; a first ammonia nitrogen detection point and a first nitric nitrogen detection point are provided between the ammoniation section and the anaerobic section, which are used to monitor the concentrations of ammonia nitrogen and nitric nitrogen after the ammoniation section, and feed back to the PLC control system to control the reflux flow of the nitrification liquid to ensure the ammoniation effect; The anaerobic section includes an anaerobic treatment module, which is used to promote the release of phosphorus by polyphosphate bacteria by absorbing organic matter under an anaerobic environment, and then release high-quality carbon sources by absorbing excessive phosphorus at the aerobic front end, thereby providing suitable conditions for simultaneous nitrification and denitrification while removing phosphorus; The anoxic section includes an anoxic treatment module, which provides nitric nitrogen by refluxing nitrification liquid, and uses a carbon source to perform denitrification under anoxic conditions to generate nitrogen gas for denitrification; The aerobic section is refluxed to the anoxic section through a nitrification liquid reflux pump via a pipeline. The nitrification liquid produced in the aerobic section contains a large amount of nitrate nitrogen, which is refluxed to the anoxic section through the nitrification liquid reflux pump to provide the anoxic section with electron acceptor nitrate nitrogen required for denitrification; The outlet end of the aerobic section is connected to the sedimentation tank. A dissolved oxygen detection point, an ammonia nitrogen detection point and an aeration mechanism are provided in the aerobic section. The dissolved oxygen detection point and the ammonia nitrogen detection point are used to detect the dissolved oxygen content and the ammonia nitrogen nitrification effect, respectively, and feed back to the PLC control system. The PLC control system controls the aeration mechanism to adjust the aeration amount in the aerobic section through an external blower based on the detection data and a preset threshold value to ensure sufficient nitrification reaction.

2. According to claim 1, a precise control device for efficient denitrification of sewage, characterized in that: The aerobic section includes an aerobic pool front section, an aerobic pool middle section and an aerobic pool end section, and the outlet end of the aerobic end section is connected to a sedimentation tank; The front section of the aerobic pool, the middle section of the aerobic pool and the end section of the aerobic pool are all provided with aeration mechanisms with valve control; The aerobic pool front section, the aerobic pool middle section and the aerobic pool end section are respectively provided with a first dissolved oxygen detection point, a second dissolved oxygen detection point and a third dissolved oxygen detection point, which are used to detect the dissolved oxygen content of the current aerobic section and feed back to the PLC control system; The middle section of the aerobic pool and the end section of the aerobic pool are respectively provided with a second ammonia nitrogen detection point and a third ammonia nitrogen detection point, which are used to detect the ammonia nitrogen nitrification effect of the current aerobic section; the outlet end of the aerobic end is provided with a fourth ammonia nitrogen detection point, which is used to detect the ammonia nitrogen content in the outlet water; The detection data obtained from the second ammonia nitrogen detection point, the third ammonia nitrogen detection point and the fourth ammonia nitrogen detection point are fed back to the PLC control system, and the aeration mechanism is controlled to adjust the aeration amount of the previous aerobic section according to a preset threshold value; A third nitric nitrogen detection point is provided in the end section of the aerobic pool, which is used to detect the nitric nitrogen content in the reflux nitrification liquid and the mixed liquid transported to the sedimentation tank, and is used to control the dissolved oxygen in the aerobic end section and the reflux flow rate of the nitrification liquid according to the nitric nitrogen concentration in the reflux nitrification liquid; And feed back to the PLC control system, and control the aeration mechanism to adjust the aeration volume of the aerobic end stage according to the preset threshold value to ensure the synchronous nitrification and denitrification of the aerobic end stage.

3. A precise control device for efficient denitrification of sewage according to claim 2, characterized in that: A second nitrate nitrogen detection point is provided after the anoxic section to determine the nitrate nitrogen content after the anoxic section and feed it back to the PLC control system. The PLC control system dynamically adjusts the operating parameters of the nitrification liquid reflux ratio through the detection data to ensure the denitrification balance of the system; The detection data of the first nitrate nitrogen detection point and the third nitrate nitrogen detection point are coordinated to calculate the denitrification efficiency coefficient of the anoxic section by comparing the change of nitrate nitrogen concentration.

4. The precise control device for efficient denitrification of sewage according to claim 1, characterized in that: The sludge separated in the sedimentation tank is transported by a sludge return pump and returned to the anaerobic section through a pipeline, providing high-concentration biomass for the treatment process of the anaerobic section.

5. A precise control device for efficient denitrification of sewage according to claim 4, characterized in that: Flow meters are provided on the pipe connecting the water inlet end and the ammoniation section, on the pipe connecting the aerobic section and the anoxic section, and on the pipe connecting the sedimentation tank and the anaerobic section for collecting and real-time monitoring flow data.

6. The precise control device for efficient denitrification of sewage according to claim 1, characterized in that: The front section of the aerobic pool is defined as a high dissolved oxygen ammonia nitrogen nitrification section, with a DO1 range of >2 mg / L; the middle section of the aerobic pool is defined as a moderate dissolved oxygen transition control section, with a DO2 range of 0.8 mg / L to 2 mg / L; the aerobic end is defined as a low dissolved oxygen simultaneous nitrification and denitrification section, with a DO3 range of 0 to 1.0 mg / L.

7. A precise control system for efficient denitrification of sewage based on any one of claims 1 to 6, characterized in that: It includes information acquisition module, parameter conversion module and intelligent control module; The information collection module includes collecting tank capacity data, flow data, detection data and valve opening data; The parameter conversion module is used to perform mathematical modeling and function fitting on the real-time data provided by the information acquisition module, so as to provide an accurate adjustment basis for the intelligent control module; The intelligent control module includes dissolved oxygen control in the aerobic tank and nitrification liquid reflux control.

8. A precise control system for efficient denitrification of sewage according to claim 7, characterized in that: The tank capacity data includes V1: anaerobic tank capacity, V2: anoxic tank capacity, V3: aerobic front tank capacity, V4: aerobic middle tank capacity and V5: aerobic end tank capacity; Flow data includes Q1: water inflow; Q2: sludge return flow; Q3: Reflux flow rate of nitrification solution; The detection data include [NO3-N]1: the first nitrate nitrogen detection point data; [NO3-N]2: the second nitrate nitrogen detection point data; [NO3-N]3: the third nitrate nitrogen detection point data; [NH3-N]1: the first ammonia nitrogen detection point data; [NH3-N]2: the second ammonia nitrogen detection point data; [NH3-N]3: the third ammonia nitrogen detection point data; [NH3-N]4: the fourth ammonia nitrogen detection point data; [DO]1: the first dissolved oxygen detection data; [DO]2: the second dissolved oxygen detection data; [DO]3: the third dissolved oxygen detection data; The valve opening data includes FM1: aeration valve 1 data; FM2: aeration valve 2 data; FM3: aeration valve 3 data; FM4: aeration valve 4 data.

9. A precise control system for efficient denitrification of sewage according to claim 8, characterized in that: The dissolved oxygen control in the aerobic pool includes the front section of the aerobic pool, the middle section of the aerobic pool and the end section of the aerobic pool; The front section of the aerobic pool: collect V1, V2, Q1, Q2, Q3, [NH3-N]1, [NH3-N]2, [DO]1 and FM4 test data, and the initial calculation is as follows: △1=[NH3-N]1-[NH3-N]2; Fit the function △1=f([DO]1) of △1 about [DO]1, and simultaneously fit the function [DO]1=f(FM4) of [DO]1 about FM4, and merge them into △1=f(FM4). Each test data is recorded, screened, and counted. As the data increases, the function △1=f(FM4) is further improved, and the inverse function FM4=f(△1) that conforms to the actual operation is obtained. Setting [NH3-N] 2设 Value, calculate △ 1设 =[NH3-N]1-[NH3-N] 2设 ; According to △ 1设 The calculated value is used to adjust the opening of the aeration valve ④ through the function FM4=f(△1). The adjustment time is delayed to the detection time of [NH3-N]1. The delay time is the calculated HRT. [NH3-N]1-[NO3-N]2 ; <h2 style=";text-align:left;direction:ltr">HRT<h2 style=";text-align:left;direction:ltr"> [NH3-N]1-[NO3-N]2 <h2 style=";text-align:left;direction:ltr"> (V1 / (Q1+Q2)+V2 / (Q1+Q2+Q3)) If the [NH3-N]2 test data is higher than [NH3-N] 2设定 , then increase the opening of the aeration valve④, and adjust the opening according to the function FM4=f(△1), the independent variables are the detection data [NH3-N]2 and the set value [NH3-N] 2设定 The difference between The middle section of the aerobic pool: collect [NH3-N]2, [NH3-N]3, [DO]2 and FM3 test data, and the initial calculation is as follows: △2=[NH3-N]2-[NH3-N]3; Fit the function of △2 about [DO]2 △2=f([DO]2), and simultaneously fit the function of [DO]2 about FM3 [DO]2=f(FM3), and merge them into △2=f(FM3). Each test data is recorded, screened, and counted. As the data increases, the △2=f(FM3) function is further improved, and the inverse function FM3=f(△2) that conforms to the actual operation is obtained; set [NH3-N] 3设 The value is calculated as follows: △ 2设 =[NH3-N]2-[NH3-N] 3设 ; According to △ 2设 The calculated value is adjusted through the function FM3=f(△2) to adjust the opening of the aeration valve ③. The adjustment time is the same as the detection time of [NH3-N]2. If the [NH3-N]3 detection data is higher than [NH3-N] 3设 , then increase the opening of the aeration valve ③, and adjust the opening according to the function FM3=f(△2), and the independent variables are the detection data [NH3-N]3 and the set value [NH3-N] 3设 The difference between The final stage of the aerobic pool: collect V3, V4, Q1, Q2, Q3, [NO3-N]2, [NO3-N]3, [NH3-N]1, [NH3-N]3, [DO]3 and FM2 test data, and the initial calculation is as follows: △3=[NO3-N]2+([NH3-N]1)×Q1 / (Q1+Q2+Q3)-[NH3-N]3-[NO3-N]3; Fit the function △3=f([DO]3) of △3 about [DO]3, and simultaneously fit the function [DO]3=f(FM2) of [DO]3 about FM2, and merge them into △3=f(FM2). Each test data is recorded, screened, and counted. As the data increases, the function △3=f(FM2) is further improved, and the inverse function FM2=f(△3) that conforms to the actual operation is obtained; Setting [NO3-N] 3设 The value is calculated as follows: <h2 style=";text-align:left;direction:ltr">△<h2 style=";text-align:left;direction:ltr"> 3设 <h2 style=";text-align:left;direction:ltr"> = [NO3-N]2+([NH3-N]1)×Q1 / (Q1+Q2+Q3)-[NH3-N]<h2 style=";text-align:left;direction:ltr"> 3设 <h2 style=";text-align:left;direction:ltr"> -[NO3-N]<h2 style=";text-align:left;direction:ltr"> 3设 <h2 style=";text-align:left;direction:ltr"> ; According to △ 3设 The calculated value is used to adjust the opening of the aeration valve ② through FM2=f(△3). The adjustment time is delayed to the detection time of [NO3-N]2. The delay time is the calculated HRT. [NO3-N]2-[NO3-N]3 ; HRT [NO3-N]2-[NO3-N]3 =(V3+V4) / (Q1+Q2+Q3); If the [NO3-N]3 test data is higher than [NO3-N] 3设 , then reduce the opening of the aeration valve ②, adjust the opening feedback to correct the FM2=f(△3) function; If the valves in the front and middle sections of the aerobic tank have been opened to the maximum extent and [NH3-N]4 is still higher than the set value, increase the opening of the aeration valve ②. If both [NO3-N]3 and [NH3-N]4 are higher than the set value at the same time, set the priority treatment object based on actual needs.

10. A precise control system for efficient denitrification of sewage according to any one of claims 7 or 9, characterized in that: The nitrification liquid reflux control includes the following: When the dissolved oxygen control adjustment in the aerobic tank cannot reduce [NO3-N]3, the nitrification liquid reflux flow rate is adjusted as follows: Collect the detection data of Q1, Q2, Q3, [NO3-N]1, [NO3-N]2 and [NO3-N]3, and the initial calculation is as follows: △4=([NO3-N]1×Q1+[NO3-N]3×(Q2+Q3)) / (Q1+Q2+Q3)-[NO3-N]2; Fit the function △4=f(Q3) of △4 about Q3. Each test data is recorded, screened and counted. As the data increases, the function △4=f(Q3) is further improved, and the inverse function Q3=f(△4) that conforms to the actual operation is obtained. Setting [NO3-N] 3设 The value is calculated as follows: <h2 style=";text-align:left;direction:ltr">△<h2 style=";text-align:left;direction:ltr"> 4设 <h2 style=";text-align:left;direction:ltr"> ([NO3-N]1×Q1+[NO3-N]<h2 style=";text-align:left;direction:ltr"> 3设 <h2 style=";text-align:left;direction:ltr"> ×(Q2+Q3)) / (Q1+Q2+Q3)-[NO3-N]2; Guidance Q3={△ 4设 -Q1×([NO3-N]1-[NO3-N]2)} / ([NO3-N] 3设 -[NO3-N]2)-Q2; According to △ 4设 The calculated value is used to adjust the nitrification solution reflux flow rate through Q3=f(△4).

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