An accurate intermittent aeration control system and method

Abstract

The present application discloses a precise intermittent aeration control system and method, which is used for precisely controlling intermittent aeration in a biochemical pool. The control system includes a control module, a blower master control cabinet, a valve group controller, and an aeration pipeline; the aeration pipeline includes a plurality of aeration grids evenly arranged in the aerobic pool, and the aeration grids divide the aerobic pool into a plurality of aeration sub-areas; an aerator is provided at the node of the aeration grid, each aeration grid is connected to an aeration branch pipe, all aeration branch pipes are collectively connected to the aeration main pipe, the aeration main pipe is connected to the blower, and each aeration branch pipe is provided with an independent pneumatic butterfly valve; the control module controls the connection between the valve group controller and the blower master control cabinet, the valve group controller controls the connection of all pneumatic butterfly valves, the blower master control cabinet controls the connection of the blower, and the pneumatic butterfly valve is provided with two operating states: an open state and an intermittent open state. By setting the pneumatic butterfly valve to the intermittent open state, energy consumption can be reduced and the efficiency of the biochemical pool can be improved.

Description

Technical Field

[0001] The present application relates to a precise intermittent aeration control system and method, and relates to the technical field of sewage treatment. Background Technique

[0002] As an important part of regional environmental governance, the electricity cost of a sewage treatment plant is its largest cost expenditure, which can account for more than 50% of the total expenditure cost.

[0003] The core treatment unit of a sewage treatment plant is biochemical treatment, and the most widely used method is activated sludge. Activated sludge undergoes different reactions under different conditions. Generally speaking, the composition of a biochemical pool can be divided into three types: anaerobic pool, anoxic pool, and aerobic pool. In actual applications, the three types of pools can be flexibly configured according to the influent conditions. A typical structure of the biochemical pool in a sewage treatment plant is as Figure 1 shown. The biochemical pool includes a pre-anoxic pool 1, an anaerobic pool 2, an anoxic pool 3, and an aerobic pool 4 connected in sequence. Generally, one or two grids are set in the anoxic pool 3, and multiple grids are set in the aerobic pool 4. To achieve oxygen supply in the aerobic pool 4, an air supply pipeline is arranged in the aerobic pool 4. In the electricity consumption composition of a sewage treatment plant, the blower that supplies oxygen to the aerobic pool 4 accounts for the largest proportion, and in some cases, it exceeds 50%. Therefore, the control of the blower and the reasonable distribution of the air volume directly affect the operating cost of the entire sewage treatment plant.

[0004] However, the following problems often exist in the control of the aeration system of a sewage treatment plant:

[0005] 1. The aeration volume in the aerobic pool does not match the actual demand. When the aeration volume is small, the biochemical reaction in the aerobic pool cannot be completed; when the aeration volume is large, it will cause sludge peroxidation and a large amount of power consumption.

[0006] 2. Common activated sludge methods all use the denitrification reaction by mixing the nitrified liquid that has completed the nitrification reaction with the influent in an anoxic environment for nitrogen removal. However, excessive aeration will damage the anoxic environment of other pools, affect the denitrification effect, and thus affect the total nitrogen removal effect.

[0007] 3. Most sewage treatment plants control the frequency of the blower based on the dissolved oxygen at the end of the aeration tank. This control method has a certain lag in the detection of dissolved oxygen, and there is also a certain lag in the feedback of the aeration volume to the dissolved oxygen. It is difficult to achieve a satisfactory effect of precise aeration and will also cause a large amount of energy consumption waste.

[0008] 4. The actual load of the sewage treatment plant deviates greatly from the designed load and changes violently. There are many sewage treatment plants with the phenomena of carbon deficiency, high nitrogen and phosphorus.

[0009] 5. Some sewage treatment plants now use the method of intermittent operation of blowers to enhance denitrification while saving energy, but this artificial control method is not accurate enough and has limitations. Summary of the invention

[0010] The technical problem to be solved by the present application is how to perform intermittent aeration of the aerobic pool and reduce power consumption while maintaining the sewage treatment efficiency of the biochemical pool, so as to solve the problems that the current aeration volume of the biochemical pool does not match the actual demand, the high dissolved oxygen caused by excessive aeration damages the anoxic effect, the energy waste caused by the rough control of the aeration system, the large deviation and drastic change of the actual load from the design load, and the limitations of conventional intermittent aeration.

[0011] In order to solve the above technical problems, the technical solution of the present application is to provide a precise intermittent aeration control system for precisely controlling intermittent aeration in a biochemical pool, wherein the biochemical pool includes a pre-anoxic pool, an anaerobic pool, an anoxic pool and an aerobic pool connected in sequence, and also includes an internal return pipe connected from the aerobic pool to the anoxic pool and an external return pipe connected from the external sedimentation area to the pre-anoxic pool, characterized in that the control system includes a control module, a blower master control cabinet, a valve group controller, and an aeration pipeline; the aeration pipeline includes a plurality of aeration grids evenly arranged in the aerobic pool The aeration grid divides the aerobic pool into multiple aeration sub-areas; an aerator is provided on the node of the aeration grid, each aeration grid is connected to an aeration branch pipe, all the aeration branch pipes are connected to the aeration main pipe, the aeration main pipe is connected to the blower, and each aeration branch pipe is provided with an independent pneumatic butterfly valve; the control module controls the connection between the valve group controller and the blower master control cabinet, the valve group controller controls the connection of all pneumatic butterfly valves, the blower master control cabinet controls the connection of the blower, and the pneumatic butterfly valve has two operating states: an open state and an intermittent open state.

[0012] Specifically, the intermittent opening state is set as follows: the pneumatic butterfly valve is in a closed state, and the valve group controller periodically opens and closes the pneumatic butterfly valve to emit a single pulse mode airflow into the pool.

[0013] Preferably, the control system also includes an acquisition module, which includes: an ammonia nitrogen meter arranged in the middle section of the aerobic tank for measuring the ammonia nitrogen data A of the section, a dissolved oxygen meter arranged at the water inlet point of the aerobic tank, the installation place of the ammonia nitrogen meter, and the return point of the aerobic tank for respectively measuring the dissolved oxygen values ​​D1, D2, and D3 of the section, a nitrate nitrogen meter arranged at the water inlet point of the aerobic tank and the return point of the aerobic tank for respectively measuring the nitrate nitrogen values ​​X1 and X2 of the section, an inlet flow meter arranged at the water inlet of the biochemical tank for measuring the inlet flow rate Q1 of the biochemical tank, a nitrification liquid reflux flow meter arranged on the inner reflux pipe for measuring the nitrification liquid reflux flow rate Q2, and a sludge reflux flow meter arranged on the outer reflux pipe for measuring the sludge reflux flow rate Q3; the acquisition module is connected to the control module.

[0014] With the above control system, the calculation module of this application includes an accurate intermittent aeration control method, which is characterized by dividing the aerobic tank into multiple aeration sub-regions using an aeration grid, judging the intermittent aeration state of each aeration sub-region through an algorithm, and regulating the air volume. The specific steps are as follows:

[0015] Step 1: Number the aeration sub-regions controlled by each aeration branch pipe according to the water flow direction, denoted as B1, B2... Bn respectively, and number the valves on the aeration branch pipes, denoted as 1, 2... n respectively.

[0016] Step 2: Calculate the real-time residence time T of a single aeration sub-region:

[0017]

[0018] In the formula: V - the effective volume of a single aeration sub-region;

[0019] Actual aeration residence time T 总 = nT;

[0020] Step 3: Calculate the ammonia nitrogen removal rate v of the aeration area in front of the ammonia nitrogen meter:

[0021]

[0022] In the formula: A1 - the set ammonia nitrogen value of the influent water of the aerobic tank;

[0023] n1 - the number of aeration sub-regions in the aeration state in front of the ammonia nitrogen meter;

[0024] Step 4: Calculate the critical value An for each aeration sub-region to start aeration:

[0025] An = βvT(n - n1)

[0026] In the formula: An - the opening critical value of the aeration sub-region controlled by the nth valve;

[0027] β - the revision parameter, determined by the slope change of on-site nitrification experiments;

[0028] Step 5: Judge the operating state of the pneumatic butterfly valve:

[0029] When A0 > An, the pneumatic butterfly valve of the aeration sub-region represented is in the open state;

[0030] When A0 ≤ An, the pneumatic butterfly valve of the aeration sub-region represented is in the intermittent open state;

[0031] In the formula, A0 is the reference value;

[0032] Step 6: Calculate the nitrate nitrogen removal rate vdef of the anoxic tank

[0033]

[0034] Where: Vdeficient—the effective volume of the anoxic tank;

[0035] Step Seven: Determine whether the aerobic tank can complete the nitrification reaction under the current operating state;

[0036] Determine whether the current denitrification reaction has not been completed;

[0037] If either of the above two points is not satisfied, all pneumatic butterfly valves in front of the ammonia nitrogen meter are set to the open state;

[0038] If both of the above two points are satisfied, according to the nitrate nitrogen removal rate vdeficient, the nitrate nitrogen value X1 at the aerobic influent point, and the real-time residence time T of a single aeration sub-region, calculate the number of valves n2 to be intermittently opened

[0039]

[0040] Specifically, in Step Seven, the judgment criteria for determining whether the aerobic tank can complete the nitrification reaction under the current operating state are: when at least one of all valves at the rear end of the ammonia nitrogen meter is in the intermittent operation state, it can be judged that the nitrification reaction has been completed under the current state; the judgment criteria for determining whether the current denitrification reaction has not been completed are: manually input the reference value X, when X1 > X, it is judged that the current denitrification reaction has not been completed.

[0041] Preferably, it further includes Step Eight of precisely controlling the air volume output of the blower:

[0042] Control the blower according to the number of pneumatic butterfly valves set to the open state, the measured values of the ammonia nitrogen meter, and the dissolved oxygen meter. The specific steps are as follows:

[0043] 8.1 Count the number of aeration sub-regions where the pneumatic butterfly valves are currently in the open state, denoted as m;

[0044] 8.2 Set a balanced air volume value denoted as C;

[0045] 8.3 Based on the balanced air volume C, use the difference between the current ammonia nitrogen value A and the internal control effluent ammonia nitrogen index. When it is higher than the internal control value, increase the air volume; conversely, decrease the air volume. The system adjustment ratio can reach ±100%, and obtain the roughly adjusted air volume D;

[0046] 8.4 Based on the roughly adjusted air volume D, finely adjust the air volume according to the change rate of the ammonia nitrogen value. The change rate range of the ammonia nitrogen value is [-100%, +100%], and the finely adjusted air volume adjustment ratio is [-30%, +30%]. The air volume forms a linear relationship with the system adjustment ratio, and perform a fine adjustment on the air volume to obtain the finely adjusted air volume E;

[0047] 8.5 On the basis of finely adjusting the air volume E, finely adjust the air volume according to the current value of the dissolved oxygen D2. Set a standard dissolved oxygen value, and finely adjust the air volume according to the deviation range between the actual dissolved oxygen value D2 and the standard dissolved oxygen value. The adjustment ratio of the finely adjusted air volume is [-10%, +10%] to obtain the finely adjusted air volume F.

[0048] 8.6 On the basis of the finely adjusted air volume F, adjust F according to the subsequent m value, and magnify or reduce the whole according to the comparison between the number of opened valves and the standard value, and finally obtain the output air volume G.

[0049] Among them, in the step 8.2, the balanced air volume value C is derived from manual input or the following calculation formula:

[0050] C = γQ1

[0051] In the formula: γ—the average monthly air-water ratio. Description of the Drawings

[0052] Figure 1 It is a schematic diagram of the typical structure of the biochemical tank;

[0053] Figure 2 It is a schematic diagram of the aeration pipeline structure provided in the embodiment;

[0054] Figure 3 It is a structure diagram of the precise intermittent aeration control system. Detailed Embodiment

[0055] To make the present application more obvious and understandable, the preferred embodiments are described in detail below in conjunction with the drawings.

[0056] Embodiment

[0057] This embodiment provides a precise intermittent aeration control system and method. Figure 1 The figure shows the structure of the biochemical tank of a certain sewage treatment plant. The biochemical tank includes a pre-anoxic tank 1, an anaerobic tank 2, an anoxic tank 3, and an aerobic tank 4 connected in sequence. The anoxic tank 3 has two compartments, and the aerobic tank 4 has five compartments. It also includes an internal reflux pipeline connecting from the aerobic tank 4 to the anoxic tank 3 and an external reflux pipeline connecting from the external sedimentation area to the pre-anoxic tank 1;

[0058] To achieve precise intermittent aeration control, it is necessary to add the following on the basis of the above biochemical tank structure:

[0059] An ammonia nitrogen meter 131 is set in the middle section of the aerobic tank 4 for measuring the ammonia nitrogen data A at the section where the meter is located. The specific position of the ammonia nitrogen meter 131 is calculated according to the following formula:

[0060]

[0061] Where: W—the percentage of the distance from the instrument to the total length of the aerobic influent and the aerobic zone, %;

[0062] a—revision parameter, determined by the slope change of on-site nitrification experiments;

[0063] K—design coefficient of the sewage treatment plant;

[0064] Cset—the product of the designed effluent ammonia nitrogen value and the COD (chemical oxygen demand) value;

[0065] Cinner—the product of the in-control effluent ammonia nitrogen value and the COD value;

[0066] η—the percentage of the number of days with an influent pollution load of 70% or less in the whole year.

[0067] Three DO meters (dissolved oxygen meters) are set at the aerobic influent point, the installation location of ammonia nitrogen meter 131, and the aerobic return point: the first dissolved oxygen meter 111, the second dissolved oxygen meter 112, and the third dissolved oxygen meter 113, which are respectively used to measure the dissolved oxygen values of the sections where they are located, denoted as D1, D2, and D3.

[0068] Two nitrate nitrogen meters are set at the aerobic influent point and the aerobic return point: the first nitrate nitrogen meter 121 and the second nitrate nitrogen meter 122, which are respectively used to measure the nitrate nitrogen values of the sections where they are located, denoted as X1 and X2.

[0069] The influent flow meter 101 is set at the inlet of the biochemical tank to measure the influent flow of the biochemical tank, denoted as Q1.

[0070] The nitrification liquid return flow meter 102 is set on the internal return pipeline to measure the nitrification liquid return flow, denoted as Q2.

[0071] The sludge return flow meter 103 is set on the external return pipeline to measure the sludge return flow, denoted as Q3.

[0072] Aeration grids are evenly set in the aerobic tank 4 according to the area. Aerators are set at the nodes of the aeration grids. The aeration branch pipes are connected to each aeration grid. The aeration area and the number of aerators controlled by each aeration branch pipe are the same or nearly the same. Taking... Figure 1 、 2 as an example, a total of 18 aeration grids and 18 aeration branch pipes are set in five aerobic tanks 4. A pneumatic butterfly valve 401-4018 is installed on each aeration branch pipe and numbered according to the water flow direction;

[0073] The pneumatic butterfly valves are divided into two operating states: open state and intermittent open state;

[0074] Open state: The valve is in the open state;

[0075] Intermittent opening state: The valve is in the closed state, and the valve group controller periodically opens and closes the valve, sending a single - pulse - mode air flow (about 3% to 4% of the total air volume) to the aeration grid; In the intermittent opening state, the valve periodically opens and closes, and the specific opening and closing cycle can be set. In this embodiment, it is set to close for 30 minutes and open for 2 minutes.

[0076] Each pneumatic butterfly valve in the aerobic tank 4 is controlled by a valve group controller. Five aerobic tanks 4 correspond to five valve group controllers. Specifically, the first valve group controller 301 controls the first pneumatic butterfly valve 401, the second pneumatic butterfly valve 402, the third pneumatic butterfly valve 403, the fourth pneumatic butterfly valve 404, and the fifth pneumatic butterfly valve 405 corresponding to the first aerobic tank. The second valve group controller 302, the third valve group controller 303, the fourth valve group controller 304, and the fifth valve group controller 305 respectively control the pneumatic butterfly valves in the corresponding aerobic tanks.

[0077] All aeration branch pipes are aggregated into the aeration main pipe. The air supply of the aeration main pipe is provided by a blower. Multiple blowers can be set to meet the air supply requirements. In this embodiment, three blowers are used, namely the first blower 411, the second blower 412, and the third blower 413. All three blowers are magnetic - levitation blowers and are controlled by the blower master control cabinet 311; The total aeration volume of the aeration main pipe is measured by a gas flow meter 141 installed on the aeration main pipe, denoted as q.

[0078] The control module is used to execute the control method and issue control instructions.

[0079] In summary, the valve group controller receives the signal transmitted from the control module and specifically controls the pneumatic butterfly valve according to the signal; The blower master control cabinet 311 receives the air volume signal transmitted from the control module and adjusts the frequency of the blower according to the air volume signal to provide the required air volume; Specifically, the blower master control cabinet can use PID regulation to control the blower frequency according to the air volume signal.

[0080] The control module reads the measurement data of all instruments, calculates according to the internal control method, and after obtaining the calculation result, transmits the control instruction to the valve group controller or the blower master control cabinet 311 for specific regulation.

[0081] The control method is as follows:

[0082] Step 1: According to the water flow direction, number the aeration sub - regions controlled by each aeration branch pipe, denoted as B1, B2... Bn respectively, and number the valves on the aeration branch pipes, denoted as 1, 2... n respectively.

[0083] Step 2: Calculate the real - time residence time T of a single aeration sub - region:

[0084]

[0085] Where: T—the real-time residence time of a single aeration sub-region (h);

[0086] V—the effective volume of a single aeration sub-region (m 3 );

[0087] The actual residence time of aeration T 总 = nT; The value of T is calculated in real time, rounded off, and displayed in real time.

[0088] Step 3. Calculate the ammonia nitrogen removal rate v of the aeration area in front of the ammonia nitrogen meter 131 according to the set influent information, the reading of the ammonia nitrogen meter 131, and the residence time T:

[0089]

[0090] Where: v—the ammonia nitrogen removal rate of the aeration area in front of the ammonia nitrogen meter 131 (mg / min);

[0091] A1—the set ammonia nitrogen value of the influent of the aerobic tank (mg / L);

[0092] A—the reading of the ammonia nitrogen meter 131;

[0093] n1—the number of aeration sub-regions in the aeration state in front of the ammonia nitrogen meter 131.

[0094] Step 4. Calculate the critical value An for each aeration sub-region to start aeration according to the ammonia nitrogen removal rate v and the residence time from the ammonia nitrogen meter 131 to each valve in the subsequent section:

[0095] An = βvT(n - n1)

[0096] Where: An—the opening critical value of the aeration sub-region controlled by the nth valve (mg / L);

[0097] β—the revision parameter, determined by the slope change of the on-site nitrification experiment.

[0098] Step 5. Judge the operating state of the pneumatic butterfly valve:

[0099] When A0 > An, the pneumatic butterfly valve of the represented aeration sub-region is in the open state;

[0100] When A0 ≤ An, the pneumatic butterfly valve of the represented aeration sub-region is in the intermittent open state;

[0101] Here, A0 is a reference value, indicating the measured value of the water in the aeration sub-region at the ammonia nitrogen meter some time ago.

[0102] Step 6. According to the effective volume of the anoxic tank Vdef (m 3) Calculate the nitrate nitrogen removal rate v_deficient (mg / min) in the anoxic tank based on the nitrate nitrogen value X2 at the aerobic reflux point and the comprehensive flow rate:

[0103]

[0104] Step 7: Determine whether the nitrification reaction can be completed under the current operating state of the aerobic tank and whether the current denitrification reaction has not been completed;

[0105] Specifically, when at least one of all the valves behind the ammonia nitrogen meter is in an intermittent operation state, it can be determined that the nitrification reaction has been completed under the current state;

[0106] For the denitrification reaction, a reference value X = 1.0 mg / L can be manually input. When X1 > X, it is determined that the current denitrification reaction has not been completed;

[0107] If either of the above two points is not satisfied, that is, the nitrification reaction is not completed or the denitrification reaction has been completed, all the pneumatic butterfly valves in front of the ammonia nitrogen meter 131 are opened;

[0108] If both of the above two points are satisfied, that is, the nitrification reaction has been completed and the denitrification reaction has not been completed. According to the nitrate nitrogen removal rate v_deficient, the nitrate nitrogen value X1 at the aerobic influent point, and the real-time residence time T of a single aeration sub-region, calculate the number of valves n2 that can be intermittently opened.

[0109]

[0110] According to the above steps, the number of pneumatic butterfly valves in the open state and the number of pneumatic butterfly valves in the intermittent open state can be adjusted according to the real-time state of the biochemical tank, and intermittent aeration can be carried out adaptively; to more accurately control the output air volume of the blower, the following method can be used:

[0111] Step 8: Control the blower in combination with the number of pneumatic butterfly valves in the open state according to the measured values of the ammonia nitrogen meter 131 and the DO meter. The specific method is as follows:

[0112] 8.1 Count the number of aeration sub-regions where the pneumatic butterfly valves are currently in the open state, denoted as m;

[0113] 8.2 Set a balanced air volume value denoted as C. This value can be obtained from manual input and calculation and can be flexibly adjusted according to the situation of each plant; specifically, the calculation method of the C value is different according to the situation of each plant station. In this embodiment, a simple calculation formula is proposed:

[0114] C = γQ1

[0115] In the formula: C - balanced air volume;

[0116] γ - monthly average air-water ratio;

[0117] In this embodiment, C is taken as 6000 m 3 / h.

[0118] 8.3 On the basis of the balanced air volume C, using the difference between the current ammonia nitrogen value A and the internal control ammonia nitrogen index of the effluent, when it is higher than the internal control value, the air volume is increased, and vice versa, the air volume is decreased. The system adjustment ratio can reach ±100%, and the roughly adjusted air volume D is obtained.

[0119] 8.4 On the basis of the roughly adjusted air volume D, the roughly adjusted air volume is finely adjusted according to the change rate of the ammonia nitrogen value. The change rate range of the ammonia nitrogen value is [-100%, +100%], and the fine adjustment air volume adjustment ratio is [-30%, +30%]. The air volume and the system adjustment ratio form a linear relationship, and the air volume is finely adjusted to obtain the finely adjusted air volume E.

[0120] 8.5 On the basis of the finely adjusted air volume E, the finely adjusted air volume is precisely adjusted according to the current value of the dissolved oxygen D2. A standard dissolved oxygen value (0.75 is used in this embodiment) is set, and the air volume is precisely adjusted according to the deviation amplitude between the actual dissolved oxygen D2 value and the standard value. The precise adjustment air volume adjustment ratio is [-10%, +10%], and the precisely adjusted air volume F is obtained.

[0121] 8.6 On the basis of the precisely adjusted air volume F, F is adjusted according to the m value, and the overall opening or closing of the valves is enlarged or reduced according to the comparison between the number of opened valves and the standard opening value of the valves, and finally the output air volume G is obtained.

[0122] In this embodiment, there are 18 valves in total, and the standard opening value of the valves is set to 9. The output air volume G can be obtained according to the following formula:

[0123]

[0124] In the formula: n3—the number of valves currently in the open state;

[0125] Finally, the PID logic among the blower, the master control cabinet, and the gas flowmeter adjusts the frequency of the blower according to the output air volume G, so that the blower outputs the air volume G.

Claims

1. A precise intermittent aeration control method, using a precise intermittent aeration control system, for precisely controlling intermittent aeration in a biochemical pool, wherein the biochemical pool comprises a pre-anoxic pool, an anaerobic pool, an anoxic pool and an aerobic pool connected in sequence, and further comprises an inner return pipe connected from the aerobic pool to the anoxic pool and an outer return pipe connected from an outer sedimentation zone to the pre-anoxic pool, It is characterized in that The control system includes a control module, a blower master control cabinet, a valve group controller, and an aeration pipeline. The aeration pipeline includes a plurality of aeration grids evenly arranged in the aerobic tank. The aeration grids divide the aerobic tank into a plurality of aeration sub-areas. Aerators are arranged at the nodes of the aeration grids. Each aeration grid is connected to an aeration branch pipe. All aeration branch pipes are collectively connected to the aeration main pipe. The aeration main pipe is connected to the blower. Each aeration branch pipe is provided with an independent pneumatic butterfly valve. The control module controls the connection between the valve group controller and the blower master control cabinet. The valve group controller controls the connection of all pneumatic butterfly valves. The blower master control cabinet controls the connection of the blower. The pneumatic butterfly valve has two operating states: an open state and an intermittent open state. The intermittent open state is set as: the pneumatic butterfly valve is in a closed state. The valve group controller periodically opens and closes the pneumatic butterfly valve. A single pulse mode airflow is emitted into the pool. The control system also includes a collection module, which includes: an ammonia nitrogen meter arranged in the middle section of the aerobic pool for measuring the ammonia nitrogen data A of the section, a dissolved oxygen meter arranged at the water inlet of the aerobic pool, the installation place of the ammonia nitrogen meter, and the return point of the aerobic pool for respectively measuring the dissolved oxygen values ​​D1, D2, and D3 of the section, a nitrate nitrogen meter arranged at the water inlet of the aerobic pool and the return point of the aerobic pool for respectively measuring the nitrate nitrogen values ​​X1 and X2 of the section, an inlet flow meter arranged at the water inlet of the biochemical pool for measuring the water inlet flow Q1 of the biochemical pool, a nitrification liquid reflux flow meter arranged on the inner reflux pipe for measuring the nitrification liquid reflux flow Q2, and a sludge reflux flow meter arranged on the outer reflux pipe for measuring the sludge reflux flow Q3. The collection module is connected to the control module, characterized in that: The specific steps of the control method are as follows: Step 1: According to the direction of water flow, the aeration sub-areas controlled by each aeration branch pipe are numbered as B1, B2...Bn, and the valves on the aeration branch pipes are numbered as 1, 2...n; Step 2: Calculate the real-time residence time T of a single aeration sub-area: Where: V is the effective volume of a single aeration sub-area; Actual aeration residence time T 总 = nT; Step 3: Calculate the ammonia nitrogen removal rate v in the aeration area before the ammonia nitrogen meter: Where: A1—set ammonia nitrogen value of aerobic pool influent; n1—the number of aeration sub-areas in aeration state in front of the ammonia nitrogen meter; Step 4: Calculate the critical value An for each aeration sub-area to start aeration: An=βvT(n-n1) Where: An is the critical opening value of the aeration sub-area controlled by the nth valve; β—revised parameter, determined by the slope change of the field nitrification experiment; Step 5: Determine the operating status of the pneumatic butterfly valve: When A0>An, the pneumatic butterfly valve of the aeration sub-area represented is in the open state; When A0 ≤ An, the pneumatic butterfly valve of the aeration sub-region represented is in an intermittent opening state; In the formula, A0 is a reference value; Step 6. Calculate the nitrate nitrogen removal rate vdeficient of the anoxic tank: In the formula: Vdeficient —— The effective volume of the anoxic tank; Step 7. Determine whether the nitrification reaction can be completed in the aerobic tank under the current operating state. The judgment criterion is: when at least one of all the valves at the rear end of the ammonia nitrogen meter is in an intermittent operating state, it can be judged that the nitrification reaction has been completed under the current state; Judge whether the current denitrification reaction has not been completed. The judgment criterion is: Manually input the reference value X. When X1 > X, it is judged that the current denitrification reaction has not been completed; If either of the above two points is not satisfied, all the pneumatic butterfly valves in front of the ammonia nitrogen meter are set to the open state; If both of the above two points are satisfied, according to the nitrate nitrogen removal rate vdeficient, the nitrate nitrogen value X1 at the aerobic influent point, and the real-time residence time T of a single aeration sub-region, calculate the number of valves n2 for intermittent opening: Step 8. Control the blower according to the number of pneumatic butterfly valves set to the open state, the measured values of the ammonia nitrogen meter and the dissolved oxygen meter. The specific steps are as follows: 8.1 Count the number of aeration sub-regions where the pneumatic butterfly valve is currently in the open state, denoted as m; 8.2 Set a balanced air volume value denoted as C; 8.3 Based on the balanced air volume C, use the difference between the current ammonia nitrogen value A and the internal control effluent ammonia nitrogen index. When it is higher than the internal control value, increase the air volume, otherwise decrease the air volume. The system adjustment ratio can reach ±100%, and obtain the roughly adjusted air volume D; 8.4 Based on the roughly adjusted air volume D, finely adjust the air volume according to the change rate of the ammonia nitrogen value. The change rate range of the ammonia nitrogen value is [-100%, +100%], and the finely adjusted air volume adjustment ratio is [-30%, +30%]. The air volume and the system adjustment ratio form a linear relationship, and finely adjust the air volume to obtain the finely adjusted air volume E; 8.5 Based on the finely adjusted air volume E, finely adjust the finely adjusted air volume according to the current value of the dissolved oxygen D2. Set a standard dissolved oxygen value, and finely adjust the air volume according to the deviation range between the actual dissolved oxygen D2 value and the standard dissolved oxygen value. The finely adjusted air volume adjustment ratio is [-10%, +10%], and obtain the finely adjusted air volume F; 8.6 Based on the finely adjusted air volume F, adjust F according to the latter m value, and perform overall amplification or reduction according to the comparison between the valve opening number and the standard value, and finally obtain the output air volume G.

2. According to an accurate intermittent aeration control method as described in claim 1, It is characterized in that In step 8.2, the balanced air volume value C is derived from manual input or the following calculation formula: C = γQ1 In the formula: γ —— The monthly average air-water ratio.

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