Precise phosphorus removal control method for efficient sedimentation tank based on magnetizing medium

Abstract

The invention discloses a precise phosphorus removal control method for a high-efficiency sedimentation tank based on a magnetic medium, and relates to the technical field of sewage phosphorus removal. The method comprises the following four steps: carrying out real-time water inlet parameter acquisition on a magnetic powder feeding tank, a mixing tank, a flocculation tank and an efficient sedimentation tank, carrying out multivariable dynamic modeling to cooperatively calculate the agent feeding amount, and carrying out agent feeding and water outlet parameter feedback regulation. The method comprises the following steps: monitoring the flow of inlet water, the total phosphorus concentration and the suspended matter concentration in real time, establishing a quadratic polynomial model of the total phosphorus removal rate by combining the interaction formed by sequentially mixing magnetic powder, a flocculating agent and a coagulant aid with sewage to react, and dynamically calculating the theoretical dosage of the three agents; monitoring and feeding back the total phosphorus concentration and the suspended matter concentration of effluent at a water outlet end, and dynamically adjusting the dosage of the medicament according to the total phosphorus concentration and the suspended matter concentration; precise adding of a dephosphorization agent is achieved, the dephosphorization effect is improved, the operation cost is reduced, and the automation level is improved. The problems that in an existing sewage precipitation phosphorus removal process, the agent adding amount is difficult to accurately control, and the automation degree is low are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage phosphorus removal, and particularly relates to a precise phosphorus removal control method based on an efficient sedimentation tank with magnetic medium addition. Background Art

[0002] In the field of sewage treatment, the effective removal of phosphorus is of great significance for preventing water eutrophication and ensuring ecological safety.

[0003] At present, the main methods for sewage phosphorus removal in sewage treatment plants are biological phosphorus removal and chemical phosphorus removal.

[0004] Among them, biological phosphorus removal reduces the phosphorus content in sewage through the enrichment of polyphosphate-accumulating organisms, which has the advantages of economy and environmental protection. However, in actual operation, it is difficult to stably achieve the discharge standard of total phosphorus (TP) in the effluent lower than 0.5 mg / L solely relying on biological phosphorus removal. Therefore, usually, after the biological phosphorus removal treatment process, a chemical phosphorus removal treatment process is supplemented to ensure that the effluent quality at the end meets the standard.

[0005] Chemical phosphorus removal mainly realizes phosphorus removal by adding agents such as aluminum salts or iron salts to sewage to form insoluble precipitates with dissolved phosphorus in water.

[0006] In recent years, the development of the magnetic coagulation sedimentation technology has provided a new solution for the advanced treatment of sewage. In this technology, magnetic medium is introduced during the processes of coagulation, flocculation, and sedimentation, making it the core particle of the floc, enhancing the floc density, accelerating the sedimentation speed, and significantly improving the sedimentation efficiency and hydraulic load of the sedimentation tank. The magnetic coagulation sedimentation technology has been applied to the advanced treatment unit of sewage treatment plants and used in combination with phosphorus removal agents to further reduce the TP data and suspended solid concentration in the effluent.

[0007] However, currently, the control of the dosage of phosphorus removal agents in magnetic coagulation sedimentation tanks mostly relies on the empirical method, that is, operators infer the dosage of phosphorus removal agents based on the effluent situation of the front-end process and the TP data at the discharge port. This method has problems such as strong subjectivity and response lag, and it is difficult to achieve precise control.

[0008] Therefore, some sewage treatment plants have introduced an automatic dosing system to estimate the dosage of agents based on the TP data of the effluent and the influent flow rate, and make corrections according to the commissioning experience. Due to the data lag in online TP detection and the lack of full consideration of the interaction between agents, the system often needs to overdose phosphorus removal agents and magnetic medium to ensure that the effluent quality at the end meets the standard, but this operation directly increases the process cost of sewage sedimentation and phosphorus removal.

[0009] In addition, most existing automatic chemical dosing systems rely on a single parameter, such as the TP concentration, as the control basis, lacking the collaborative consideration of multiple parameters of sewage and being difficult to cope with the impact brought by the fluctuation of influent water quality, making it impossible to accurately control the dosing amounts of phosphorus removal agents and magnetic media. For example, the BOD / TP ratio in sewage has a significant impact on the biological phosphorus removal effect. When this ratio is unbalanced, the biological phosphorus removal efficiency decreases, and it is necessary to compensate by accurately dosing carbon sources or adjusting the dosing amount of chemical phosphorus removal agents. However, the existing automatic chemical dosing systems have limited control capabilities in this regard and are difficult to achieve dynamic adjustment.

[0010] There are multiple technical problems in the existing technology: 1. The control accuracy of dosing amount is insufficient due to lagging data feedback: The chemical dosing control depends on experience or lagging online detection data of the effluent at the back end, making it difficult to achieve real-time and accurate adjustment of the chemical dosing link at the front end; 2. The coupling effect of multiple variables is not effectively considered: The existing control strategies do not systematically quantify the interactive effects among multiple parameters such as the dosing amount of magnetic media, the types of agents, and hydraulic conditions, making it impossible to achieve collaborative optimization of multiple factors and difficult to cope with the impact brought by the fluctuation of influent water quality; 3. The operating cost increases due to excessive dosing of agents: The interaction between agents is not fully considered, and there is an excessive dosing phenomenon. Although the conservative excessive dosing strategy can ensure the compliance of the effluent, it significantly increases the consumption of agents, the loss of magnetic media, and the sludge disposal cost, restricting the process economy and increasing the operating cost; 4. The degree of automation is low: The degree of automation of the system is not high, and the operation is complex, increasing the difficulty of operation and management.

[0011] In summary, it is found that the existing technology has at least the following technical problems: In the existing sewage sedimentation and phosphorus removal process, there are technical problems such as low control accuracy of the dosing amount of agents, inability to achieve collaborative optimization of multiple parameters such as the dosing amount of magnetic media, the types of agents, and hydraulic conditions, and excessive dosing of agents caused by low degree of automation. Summary of the Invention

[0012] The purpose of the present invention is to provide a precise phosphorus removal control method based on a high-efficiency sedimentation tank with magnetic media addition to solve the technical problems in the existing sewage sedimentation and phosphorus removal process, including low control accuracy of the dosing amount of agents, inability to achieve collaborative optimization of multiple parameters such as the dosing amount of magnetic media, the types of agents, and hydraulic conditions, and excessive dosing of agents caused by low degree of automation.

[0013] The many technical effects that can be produced by the preferred technical solutions provided by the present invention are described in detail below.

[0014] To solve the above technical problems, the present invention provides the following technical solutions: The present invention provides a precise phosphorus removal control method based on an intensified magnetic medium high-efficiency sedimentation tank, which includes sequentially arranging a magnetic powder dosing tank, a mixing tank, a flocculation tank, and a high-efficiency sedimentation tank along the direction from sewage inlet to outlet, and a controller is arranged in the sedimentation phosphorus removal process machine room; during the precise phosphorus removal process, the controller collects data, calculates the dosing amount of chemicals according to the precise phosphorus removal steps, and controls the dosing of magnetic powder, flocculant, and coagulant aid into the magnetic powder dosing tank, mixing tank, and flocculation tank in turn in a way of dynamically limiting the dosing amount, so as to precisely control the dosing amounts of magnetic powder, flocculant, and coagulant aid to achieve precise phosphorus removal; Among them, the precise phosphorus removal steps are as follows: S1. Real-time collection of influent parameters: An influent flowmeter, an influent total phosphorus concentration analyzer, and an influent online suspended solid concentration analyzer are arranged at the sewage inlet end of the magnetic powder dosing tank to respectively and real-time collect the influent flow rate, influent total phosphorus concentration, and influent suspended solid concentration at the inlet end; S2. Multivariable dynamic modeling and collaborative calculation of chemical dosing amounts: Based on the interaction relationship among the magnetic powder dosing amount A, the flocculant dosing amount B, and the coagulant aid dosing amount C, a quadratic polynomial model of total phosphorus removal rate is established; according to the influent flow rate, influent total phosphorus concentration, and the preset effluent total phosphorus concentration limit value, the controller solves the quadratic polynomial model of total phosphorus removal rate to dynamically calculate the theoretical dosing amounts A0, B0, and C0 of magnetic powder, flocculant, and coagulant aid; S3. Chemical dosing: The magnetic powder is dosed into the magnetic powder dosing tank according to A0, the flocculant is dosed into the mixing tank according to B0, and the coagulant aid is dosed into the flocculation tank according to C0. The chemicals are mixed with the flowing sewage in each tank in turn, and flocculation is completed in the flocculation tank, and finally sedimentation is completed in the high-efficiency sedimentation tank; S4. Feedback regulation of effluent parameters: An effluent flowmeter, an effluent total phosphorus concentration analyzer, and an effluent online suspended solid concentration analyzer are arranged at the effluent end of the high-efficiency sedimentation tank to real-time monitor the effluent total phosphorus concentration and effluent suspended solid concentration at the effluent end; the controller compares the measured effluent total phosphorus concentration with the effluent total phosphorus concentration limit value to judge whether the effluent is qualified: if the effluent total phosphorus concentration > the effluent total phosphorus concentration limit value, it is judged that the effluent is unqualified, then the effluent total phosphorus fluctuation value is obtained according to the deviation value between the effluent total phosphorus concentration and the effluent total phosphorus concentration limit value, and the dosing amounts of A, B, and C are dynamically corrected with a preset adjustment range; if the effluent total phosphorus concentration ≤ the effluent total phosphorus concentration limit value, it is judged that the effluent is qualified, and the fluctuation amplitude of the effluent total phosphorus fluctuation value is lower than the preset effluent total phosphorus fluctuation value threshold, then the current chemical dosing amount is maintained.

[0015] In one embodiment, the quadratic polynomial model of total phosphorus removal rate is: total phosphorus removal rate = a + b×B - c×C + d×A - e×B×C + f×B×A + g×C×A - h×B 2 + i×C 2 - j×A 2 ; Where a is the insurance coefficient, and b to j are the interaction influence coefficients of magnetic powder, flocculant, and coagulant aid.

[0016] In one embodiment, the insurance coefficient a is set at 8.80~8.95, and is set by recording the maximum value of the historical influent flow rate and the total phosphorus concentration measurement error to compensate for the prediction error of the total phosphorus removal rate caused by the deviation in the influent data collection.

[0017] In one embodiment, the coefficients b to j of the quadratic polynomial model of total phosphorus removal rate are determined through orthogonal experiments and multiple regression analysis, including: within the range of 1-4 mg / L of influent total phosphorus concentration, multiple groups of experiments are conducted by changing the dosage combination of A, B, and C, total phosphorus removal rate data are recorded, and the least squares method is used to fit to obtain the values ​​of each coefficient b to j.

[0018] In one of the embodiments, in step S4, the adjustment range is in a piecewise linear relationship with the effluent total phosphorus fluctuation value: when the effluent total phosphorus fluctuation value is ≤0.1 mg / L, the adjustment range is 2~5% of the theoretical dosage; when 0.1 mg / L<effluent total phosphorus fluctuation value ≤0.3 mg / L, the adjustment range is 5~10% of the theoretical dosage; when the effluent total phosphorus fluctuation value is >0.3 mg / L, the adjustment range is 10~15% of the theoretical dosage.

[0019] In one of the embodiments, in step S3, the stirring intensity of the magnetic powder dosing tank, the mixing tank, and the flocculation tank are respectively controlled in linkage with the dosage of A, B, and C: the stirring speed of the magnetic powder dosing tank is positively correlated with A, the stirring speed of the mixing tank is positively correlated with B, and the stirring speed of the flocculation tank is negatively correlated with C.

[0020] In one of the embodiments, in step S2, the effluent total phosphorus concentration limit value is 0.3~0.5 mg / L, and the controller automatically selects a preset dosing priority strategy according to the difference between the inlet total phosphorus concentration and the effluent total phosphorus concentration limit value: when the inlet total phosphorus concentration is greater than 3 mg / L, the dosage ratio of flocculant B is increased first; when 1 mg / L≤inlet total phosphorus concentration≤3 mg / L, the synergistic dosage of magnetic powder A and coagulant C is optimized first.

[0021] In one of the embodiments, the inlet suspended solids concentration and the outlet suspended solids concentration data of the inlet online suspended solids concentration analyzer and the outlet online suspended solids concentration analyzer are used to correct the interaction coefficients g and i in the quadratic polynomial model of total phosphorus removal rate in step S2: when the inlet suspended solids concentration is greater than 50 mg / L, the coefficient g is increased by 10-20% and the coefficient i is decreased by 5-10%; when the inlet suspended solids concentration is ≤50 mg / L, the coefficients g and i maintain the baseline value.

[0022] In one embodiment, it further includes step S5, optimization of magnetic powder recovery efficiency: The controller dynamically adjusts the dosage of A according to the magnetic powder content value of the bottom sludge in the high-efficiency sedimentation tank, so that the mass ratio of the recovered magnetic powder to the newly added magnetic powder is controlled within 1:0.3 to 1:0.8.

[0023] In one embodiment, it further includes setting a pH sensor and a temperature sensor in the high-efficiency sedimentation tank; in step S2, the controller accesses the pH sensor and the temperature sensor set in the high-efficiency sedimentation tank, and according to the pH value and water temperature data in the high-efficiency sedimentation tank obtained in real time; when it is detected that the pH value exceeds the range of 6.5 to 8.0, the coefficients e and h in the quadratic polynomial model of the total phosphorus removal rate are dynamically corrected according to the pH deviation value: if the pH deviation value > 0.5, the coefficient e increases by 10% to 15%, and the coefficient h decreases by 5% to 10%; if the pH deviation value < -0.5, the coefficient e decreases by 10% to 15%, and the coefficient h increases by 5% to 10%; at the same time, when the water temperature is lower than 10°C, the coefficients b and d are respectively increased by 20% to 30% to compensate for the decrease in the flocculation reaction rate caused by low temperature.

[0024] The beneficial effects of the present invention are as follows: This technical solution provides a precise phosphorus removal control method based on a high-efficiency sedimentation tank with a magnetic medium, and has advantages in multiple aspects such as the control accuracy of chemical dosing, the coordinated optimization of multiple water quality parameters for chemical dosing, the reduction of operating costs, and the improvement of the automation level of the sewage treatment process, thereby effectively solving the technical problems existing in the existing sewage sedimentation and phosphorus removal processes, such as low control accuracy of chemical dosing amount, inability to achieve multi-parameter coordinated optimization of magnetic medium dosing amount, chemical agent types, and hydraulic conditions, and excessive chemical dosing caused by low automation level: (1) Improve the control accuracy of chemical dosing: By setting an influent flow meter, an influent total phosphorus concentration analyzer, and an influent online suspended solid concentration analyzer at the sewage inlet end of the magnetic powder dosing tank on the sewage inlet side, the influent flow rate, influent total phosphorus concentration, and influent suspended solid concentration are collected in real time. Combining with the quadratic polynomial model of the total phosphorus removal rate based on multivariable dynamic modeling, the theoretical dosing amounts of magnetic powder, flocculant, and coagulant aid are accurately calculated, effectively avoiding the dosing lag and inaccuracy problems caused by estimating the dosing amount by the traditional empirical method, and improving the precision and real-time performance of chemical dosing control.

[0025] (2) Achieve multi-parameter coordinated optimization control: Construct a quadratic polynomial model of the total phosphorus removal rate based on the interaction of magnetic powder, flocculant, and coagulant aid, comprehensively consider the non-linear coupling relationship between different chemical agents and hydraulic conditions, so that the dosing amount of chemical agents can dynamically respond to the fluctuations of influent water quality, realize multi-variable coordinated regulation and optimization, improve the stability and reliability of phosphorus removal efficiency, and avoid excessive dosing to control the phosphorus removal cost.

[0026] (3) Reduce operating costs: Through precise calculation and dynamic adjustment mechanisms, it effectively avoids the phenomenon of excessive chemical dosing commonly found in traditional automatic chemical dosing systems, reduces the usage of chemicals and magnetic powder, decreases the sludge generation and treatment costs, and improves the economic efficiency of the entire phosphorus removal process.

[0027] (4) Improve the automation level of the magnetic medium high-efficiency sedimentation tank system: Through the influent flowmeter, influent total phosphorus concentration analyzer, influent online suspended solids concentration analyzer, effluent flowmeter, effluent total phosphorus concentration analyzer, and effluent online suspended solids concentration analyzer, multi-point online monitoring is constructed for the sewage phosphorus removal process and combined with a controller to form a closed-loop feedback control system. Combining the preset effluent limit and fluctuation threshold, the chemical dosing amount is dynamically corrected, significantly improving the automation and intelligence of the system, reducing the frequency of manual intervention, simplifying the operation process, and enhancing the convenience and efficiency of operation management.

[0028] In summary, the precise phosphorus removal control method provided in this technical solution has significantly improved in terms of phosphorus removal effect, operating cost control, and process automation control compared with the existing sewage sedimentation phosphorus removal technology, and is applicable to the construction of an automated control system for the advanced phosphorus removal process in sewage treatment plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for implementation will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 It is a schematic structural diagram of the magnetic medium high-efficiency sedimentation tank of the present invention.

[0031] Among them, the reference numerals are as follows: 1. Magnetic powder dosing tank; 11. Influent flowmeter; 12. Influent total phosphorus concentration analyzer; 13. Influent online suspended solids concentration analyzer; 2. Mixing tank; 3. Flocculation tank; 4. High-efficiency sedimentation tank; 41. Effluent flowmeter; 42. Effluent total phosphorus concentration analyzer; 43. Effluent online suspended solids concentration analyzer; 5. Controller; 6. pH sensor; 7. Temperature sensor; 8. Magnetic powder content detection device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention.

[0033] In the specific implementation manner, a precise phosphorus removal control method based on a magnetic medium high-efficiency sedimentation tank is provided, which is applicable to the advanced phosphorus removal process in the sewage treatment field. It includes four steps: real-time collection of influent parameters for the magnetic powder dosing tank 1, mixing tank 2, flocculation tank 3 and high-efficiency sedimentation tank 4, collaborative calculation of the chemical dosing amount through multivariable dynamic modeling, chemical dosing, and feedback adjustment of the effluent parameters; real-time monitoring of the influent flow rate, total phosphorus concentration and suspended solid concentration, combining the interaction formed by the magnetic powder, flocculant and coagulant aid reacting with the sewage in sequence, establishing a quadratic polynomial model of the total phosphorus removal rate, and dynamically calculating the theoretical dosing amounts of the three chemicals; monitoring and feeding back the total phosphorus concentration and suspended solid concentration of the effluent at the effluent end, and dynamically adjusting the chemical dosing amount accordingly; realizing precise dosing of the magnetic powder, flocculant and coagulant aid for phosphorus removal, improving the phosphorus removal effect, reducing the operation cost and enhancing the automation level; effectively solving the technical problems existing in the existing sewage sedimentation phosphorus removal process, such as low control accuracy of the chemical dosing amount, inability to achieve multi-parameter collaborative optimization of the magnetic medium dosing amount, chemical types and hydraulic conditions, and excessive chemical dosing caused by low automation level.

[0034] The first embodiment of the precise phosphorus removal control method based on a magnetic medium high-efficiency sedimentation tank is as Figure 1 shown, including a magnetic powder dosing tank 1, a mixing tank 2, a flocculation tank 3 and a high-efficiency sedimentation tank 4 arranged in sequence along the direction of sewage influent to effluent, and a controller 5 is arranged in the sedimentation phosphorus removal process machine room; during the precise phosphorus removal process, the controller 5 collects data, calculates the chemical dosing amount according to the precise phosphorus removal steps, and controls the dosing of magnetic powder, flocculant and coagulant aid to the magnetic powder dosing tank 1, mixing tank 2 and flocculation tank 3 in a manner of dynamically limiting the dosing amount, so as to precisely control the dosing amounts of magnetic powder, flocculant and coagulant aid to achieve precise phosphorus removal; Among them, the precise phosphorus removal steps are: S1. Real-time collection of influent parameters: An influent flowmeter 11, an influent total phosphorus concentration analyzer 12 and an influent on-line suspended solid concentration analyzer 13 are arranged at the sewage influent end of the magnetic powder dosing tank 1 to respectively collect the influent flow rate, influent total phosphorus concentration and influent suspended solid concentration at the influent end in real time; S2. Collaborative calculation of the chemical dosing amount through multivariable dynamic modeling: Based on the interaction relationship of the magnetic powder dosing amount A, the flocculant dosing amount B and the coagulant aid dosing amount C, establish a quadratic polynomial model of the total phosphorus removal rate; According to the influent flow rate, influent total phosphorus concentration and the preset effluent total phosphorus concentration limit value, the controller 5 solves the quadratic polynomial model of the total phosphorus removal rate to dynamically calculate the theoretical dosing amounts A0, B0, C0 of magnetic powder, flocculant and coagulant aid; S3. Chemical agent dosing: Add magnetic powder to the magnetic powder dosing tank 1 at A0, add flocculant to the mixing tank 2 at B0, and add coagulant aid to the flocculation tank 3 at C0. The chemicals are mixed with the flowing sewage in each tank in sequence, and flocculation is completed in the flocculation tank, and finally precipitation is completed in the high-efficiency sedimentation tank 4; S4. Effluent parameter feedback regulation: Install an effluent flowmeter 41, an effluent total phosphorus concentration analyzer 42, and an effluent online suspended solids concentration analyzer 43 at the effluent end of the high-efficiency sedimentation tank 4 to monitor the effluent total phosphorus concentration and the effluent suspended solids concentration at the effluent end in real time; The controller 5 compares the measured effluent total phosphorus concentration with the effluent total phosphorus concentration limit value to determine whether the effluent is qualified: If the effluent total phosphorus concentration > the effluent total phosphorus concentration limit value, it is judged that the effluent is unqualified. Then, obtain the effluent total phosphorus fluctuation value according to the deviation value between the effluent total phosphorus concentration and the effluent total phosphorus concentration limit value, and dynamically correct the dosing amounts of A, B, and C at a preset adjustment amplitude; If the effluent total phosphorus concentration ≤ the effluent total phosphorus concentration limit value, it is judged that the effluent is qualified, and if the fluctuation amplitude of the effluent total phosphorus fluctuation value is lower than the preset effluent total phosphorus fluctuation value threshold, maintain the current chemical agent dosing amount.

[0035] Step S5. Optimization of magnetic powder recovery efficiency: Dynamically adjust the dosing amount of A according to the magnetic powder content value of the bottom sludge in the high-efficiency sedimentation tank 4, so that the mass ratio of the recovered magnetic powder to the newly added magnetic powder is controlled between 1:0.3 and 1:0.8.

[0036] When in application, as Figure 1 shown, install a magnetic powder content detection device 8 in the high-efficiency sedimentation tank 4 to detect the magnetic powder content value of the bottom sludge in the high-efficiency sedimentation tank.

[0037] For the above step S4, for the effluent total phosphorus concentration and the effluent total phosphorus concentration limit value, the effluent total phosphorus concentration limit value is the maximum total phosphorus limit value for the effluent parameters required at the effluent end of the high-efficiency sedimentation tank 4 to reach the qualified effluent total phosphorus concentration. When the effluent total phosphorus concentration does not exceed the effluent total phosphorus concentration limit value, the effluent is qualified.

[0038] Among them, the fluctuation amplitude of the effluent total phosphorus fluctuation value and the preset effluent total phosphorus fluctuation value threshold in step S4 are used to judge the system stability of the phosphorus removal process. The preset effluent total phosphorus fluctuation value threshold can be specifically set according to the stable state amplitude required by the actual operating phosphorus removal process.

[0039] The control process realized by the precise phosphorus removal step in cooperation with the magnetic powder dosing tank 1, mixing tank 2, flocculation tank 3, high-efficiency sedimentation tank 4, and the influent flowmeter 11, influent total phosphorus concentration analyzer 12, and influent online suspended solid concentration analyzer 13 installed at the sewage inlet end, and the effluent flowmeter 41, effluent total phosphorus concentration analyzer 42, and effluent online suspended solid concentration analyzer 43 installed at the effluent end: Refer to Figure 1 and the precise phosphorus removal step; First, the controller 5 collects the influent flow rate, influent total phosphorus concentration, and influent suspended solid concentration data at the sewage inlet end before the magnetic powder dosing tank according to step S1, and then inputs the collected influent data into the quadratic polynomial model of the total phosphorus removal rate established in advance in step S2 to dynamically calculate the theoretical dosing amounts of magnetic powder, flocculant, and coagulant aid; Then it enters step S3. In the first-round chemical dosing, the corresponding chemicals are dosed into each magnetic powder dosing tank 1, mixing tank 2, and flocculation tank 3 in sequence according to the calculated theoretical dosing amounts of magnetic powder, flocculant, and coagulant aid, and the dosing is restricted according to the theoretical dosing amounts. The chemicals are mixed and superimposed with the flowing sewage in the magnetic powder dosing tank 1, mixing tank 2, and flocculation tank 3 in sequence, and the flocculation is completed in the flocculation tank 3 and the sedimentation is completed in the high-efficiency sedimentation tank 4, and then the effluent is realized at the effluent end of the high-efficiency sedimentation tank 4; Then, it enters step S4. By monitoring the water quality at the effluent end of the high-efficiency sedimentation tank 4, the effluent total phosphorus concentration and effluent suspended solid concentration data are obtained. The controller 5 compares the measured effluent total phosphorus concentration with the effluent total phosphorus concentration limit value, and according to the preset rules, corrects or maintains the dosing amounts of magnetic powder, flocculant, and coagulant aid, and takes the dosing amount data corrected or maintained in step S4 as the priority and directly enters step S3 to control the dosing amount of the next-round chemical dosing; When there are large changes in the influent flow rate, influent total phosphorus concentration, and influent suspended solid concentration measured at the sewage inlet end of the magnetic powder dosing tank 1, and the controller 5 determines that the currently used chemical dosing amount data can no longer meet the requirement of precise phosphorus removal, it is necessary to re-calculate the new theoretical chemical dosing amounts with the influent flow rate, influent total phosphorus concentration, and influent suspended solid concentration data measured at the sewage inlet end of the magnetic powder dosing tank 1, and then enter steps S3 and S4 in sequence for implementation; Among them, when the controller 5 implements steps S1 to S4, it also synchronously collects the magnetic powder content value of the bottom sludge of the high-efficiency sedimentation tank 4 through the magnetic powder content detection device 8, and controls the ratio of the magnetic powder recovered in the high-efficiency sedimentation tank 4 to the newly dosed magnetic powder in the magnetic powder dosing tank 1 according to the collected magnetic powder content value data, that is, the mass ratio of the recovered magnetic powder to the newly dosed magnetic powder is controlled at 1:0.3 - 1:0.8, and directly finally corrects the magnetic powder dosing amount in step S3.

[0040] The specific setting of the above quadratic polynomial model for the total phosphorus removal rate is: Total phosphorus removal rate = a + b×B - c×C + d×A - e×B×C + f×B×A + g×C×A - h×B 2 + i×C 2 - j×A 2 ; In the formula, a is the safety coefficient, and b to j are the interaction influence coefficients of magnetic powder, flocculant, and coagulant aid.

[0041] For the safety coefficient a: The value range of a is 8.80 - 8.95; the safety coefficient a is set by the maximum value of the measured errors of the recorded historical influent flow rate and total phosphorus concentration, and is used to compensate for the acquisition deviation of the influent flow rate, influent total phosphorus concentration, or influent suspended solid concentration in the influent data, so as to avoid prediction errors in the total phosphorus removal rate.

[0042] For the interaction influence coefficients b to j: In the multi-variable dynamic modeling collaborative calculation of chemical dosage in step S2, the coefficients b to j are determined through orthogonal experiments and multiple regression analysis, including: within the range of influent total phosphorus concentration of 1 - 4 mg / L, multiple groups of experiments are carried out by changing the dosage combinations of A, B, and C, the total phosphorus removal rate data are recorded, and the values of coefficients b to j are obtained by least squares fitting.

[0043] The relationship of mutual influence and the interaction formed by the mutual influence among magnetic powder, flocculant, and coagulant aid: (1) Interaction between magnetic powder and flocculant Positive influence: The flocculant (such as PAC, PAM) wraps the suspended solids on the surface of the magnetic powder through charge neutralization and bridging effects, forming high-density magnetic flocs and improving the sedimentation rate.

[0044] Potential problems: Excessive flocculant covering the magnetic powder: If the dosage of the flocculant is excessive, it may completely cover the surface of the magnetic powder, hindering the direct adsorption of pollutants (suspended solids) by the magnetic powder and reducing the magnetic recovery rate; Charge conflict: The surface of the magnetic powder is positively charged, while the flocculant is anionic (such as some PAMs), which may lead to a decrease in adsorption efficiency due to charge repulsion.

[0045] (2) Interaction between flocculant and coagulant aid Synergistic effect: The coagulant aid enhances the network structure formed by the flocculant by filling the gaps between flocs, making the flocs denser.

[0046] Negative influence: Wrong dosing order: If the coagulant aid is dosed first, it may cause it to preferentially adsorb suspended particles, occupy the active sites of the flocculant, and weaken the charge neutralization effect; Chemical incompatibility: The coagulant aid may change the pH of the water body, resulting in the hydrolysis failure of the flocculant (such as PAM).

[0047] (3) Interaction between magnetic powder and coagulant aid Adsorption competition: Magnetic powder may adsorb the active components in the coagulant aid, resulting in a decrease in the effective concentration of the coagulant aid, and additional coagulant aid needs to be added

[0048] Therefore, after magnetic powder, flocculant and coagulant aid are mixed with sewage in sequence, the superimposed reaction forms an interaction, synchronously restricting the treatment effect of sewage and the dosage of magnetic powder, flocculant and coagulant aid. Therefore, in step S2, the establishment of the quadratic polynomial model of the total phosphorus removal rate needs to follow the interaction relationship between magnetic powder, flocculant and coagulant aid

[0049] In step S2, the limit value of the total phosphorus concentration in the effluent is 0.3 - 0.5 mg / L, and the controller 5 automatically selects the preset chemical dosing priority strategy according to the difference between the total phosphorus concentration in the influent and the limit value of the total phosphorus concentration in the effluent: when the total phosphorus concentration in the influent > 3 mg / L, the dosing ratio of flocculant B is preferentially increased; when 1 mg / L ≤ total phosphorus concentration in the influent ≤ 3 mg / L, the co-dosage of magnetic powder A and coagulant aid C is preferentially optimized

[0050] As one of the optional implementation manners Regarding the assistance of the stirring intensity in each pool during chemical dosing in step S3 above, in order to make the reaction effect of magnetic powder, flocculant and coagulant aid in the pool better, make each link of sewage dephosphorization reach the expected effect, and save the dosage of magnetic powder, flocculant and coagulant aid

[0051] During application, in step S3, the stirring intensities of the magnetic powder dosing pool 1, the mixing pool 2 and the flocculation pool 3 are linked and controlled with the dosages of A, B and C respectively: the stirring speed of the magnetic powder dosing pool 1 is positively correlated with A, the stirring speed of the mixing pool 2 is positively correlated with B, and the stirring speed of the flocculation pool 3 is negatively correlated with C

[0052] Regarding the specific setting of the adjustment range in step S4 above, in the feedback adjustment of the effluent parameters in step S4, the adjustment range has a piecewise linear relationship with the total phosphorus fluctuation value in the effluent: when the total phosphorus fluctuation value in the effluent ≤ 0.1 mg / L, the adjustment range is 2 - 5% of the theoretical dosing amount; when 0.1 mg / L < total phosphorus fluctuation value in the effluent ≤ 0.3 mg / L, the adjustment range is 5 - 10% of the theoretical dosing amount; when the total phosphorus fluctuation value in the effluent > 0.3 mg / L, the adjustment range is 10 - 15% of the theoretical dosing amount

[0053] During application, the adjustment range is the single - time correction range for dynamically adjusting the chemical dosing amount according to the total phosphorus fluctuation value in the effluent, and realizes precise and progressive adjustment of the chemical dosing amount through the piecewise proportional control strategy, avoiding water quality fluctuations caused by over - dosing or under - dosing

[0054] Among them: when the fluctuation value of the total phosphorus in the effluent is small, small-step progressive adjustment is adopted to prevent the drastic fluctuation of the total phosphorus concentration in the effluent caused by sudden dosing, and play the role of suppressing overshoot; when the fluctuation value of the total phosphorus in the effluent is large, large-step adjustment is adopted to shorten the adjustment time of the chemical dosing amount and achieve rapid response; by judging the fluctuation value of the total phosphorus in the effluent and selecting different adjustment strategies, it is possible to avoid blind over-dosing, reduce chemical waste, achieve energy conservation and consumption reduction in chemical dosing, and reduce the cost of the sewage phosphorus removal process.

[0055] Regarding the correction of the interaction influence coefficients g and i in the quadratic polynomial model of the total phosphorus removal rate in step S2 above: As Figure 1 shown, according to the influent suspended solid concentration and effluent suspended solid concentration data measured by the influent online suspended solid concentration analyzer 13 and the effluent online suspended solid concentration analyzer 43, the interaction coefficients g and i in the quadratic polynomial model of the total phosphorus removal rate in step S2 are corrected. When the influent suspended solid concentration > 50 mg / L, the coefficient g is increased by 10 - 20%, and the coefficient i is decreased by 5 - 10%; when the influent suspended solid concentration ≤ 50 mg / L, the coefficients g and i maintain the reference values.

[0056] As Figure 1 shown, a pH sensor 6 and a temperature sensor 7 are also provided in the high-efficiency sedimentation tank 4.

[0057] During application, in step S2, the controller 5 accesses the pH sensor 6 and the temperature sensor 7 provided in the high-efficiency sedimentation tank 4 to obtain the pH value and water temperature data in the high-efficiency sedimentation tank 4 in real time.

[0058] Regarding the correction of the interaction influence coefficients e and h: The controller 5, according to the pH value data in the high-efficiency sedimentation tank 4 obtained, when it detects that the pH value exceeds the range of 6.5 - 8.0, dynamically corrects the interaction coefficients e and h according to the pH deviation value. If the pH deviation value > 0.5, the coefficient e is increased by 10 - 15%, and the coefficient h is decreased by 5 - 10%; if the pH deviation value < -0.5, the coefficient e is decreased by 10 - 15%, and the coefficient h is increased by 5 - 10%.

[0059] At the same time, the controller 5, according to the water temperature data in the high-efficiency sedimentation tank 4 obtained, when the water temperature is lower than 10 °C, the coefficients b and d are respectively increased by 20% - 30% to compensate for the decrease in the flocculation reaction rate caused by low temperature.

[0060] The second embodiment of the precise phosphorus removal control method based on the magnetic medium high-efficiency sedimentation tank. The difference between this embodiment and the first embodiment is that in step S2, the limit value of the total phosphorus concentration in the effluent is 0.3 - 0.5 mg / L, and the controller 5 automatically selects a preset chemical dosing priority strategy according to the difference between the total phosphorus concentration in the effluent and the limit value of the total phosphorus concentration in the effluent: when the total phosphorus concentration in the influent > 3 mg / L, the dosing proportion of flocculant B is preferentially increased; when 1 mg / L ≤ the total phosphorus concentration in the influent ≤ 3 mg / L, the co-dosing amount of magnetic powder A and coagulant aid C is preferentially optimized.

[0061] Specifically, for the feedback regulation at the influent end: When the total phosphorus concentration in the influent > 3 mg / L, the dosing adjustment of flocculant B is as follows: Whenever the total phosphorus concentration in the influent is detected to increase by 0.5 mg / L, the dosing proportion of flocculant B is increased by 5 - 8%, while the dosing proportion of magnetic powder A is decreased by 3 - 5%, and the dosing proportion of coagulant aid C is decreased by 2 - 3%; If the increase amplitude of the total phosphorus concentration in the influent continuously > 5 mg / L for more than 30 minutes, the upper limit of the dosing proportion of flocculant B is increased to 80%, and the lower limits of the proportions of magnetic powder A and coagulant aid C are respectively decreased to 15% and 5%.

[0062] When 1 mg / L ≤ the total phosphorus concentration in the influent ≤ 3 mg / L, the dosing adjustment of magnetic powder A and coagulant aid C is as follows: If the influent suspended solid concentration > 50 mg / L, the proportion of magnetic powder A is increased by 10 - 15%, and the proportion of coagulant aid C is decreased by 10 - 15%; If the influent suspended solid concentration ≤ 50 mg / L, the proportions of magnetic powder A and coagulant aid C are evenly distributed at a ratio of 1:1.

[0063] For the feedback regulation at the effluent end: when the difference between the value of the total phosphorus concentration in the effluent and the limit value of the total phosphorus concentration in the effluent ≤ 0.1 mg / L, the dosing proportions of magnetic powder A and coagulant aid C are temporarily adjusted at a ratio of 2:1 until the total phosphorus concentration in the effluent is stably lower than the limit value of the total phosphorus concentration in the effluent.

[0064] Through the precise phosphorus removal control method based on the magnetic medium high-efficiency sedimentation tank, in terms of the control accuracy of chemical dosing, the coordinated optimization of chemical dosing for multiple water quality parameters, the reduction of operating costs, and the improvement of the automation level of the sewage treatment process, it has the following advantages: Improve the control accuracy of chemical dosing. By installing an influent flowmeter 11, an influent total phosphorus concentration analyzer 12, and an influent online suspended solids concentration analyzer 13 at the sewage inlet end of the magnetic powder dosing tank 1 on the sewage inlet side, the influent flow rate, influent total phosphorus concentration, and influent suspended solids concentration are collected in real time. Combining with the quadratic polynomial model of the total phosphorus removal rate based on multivariable dynamic modeling, the theoretical dosing amounts A0, B0, and C0 of magnetic powder, flocculant, and coagulant aid are accurately calculated, which can effectively avoid the problems of dosing lag and inaccuracy caused by estimating dosing amounts using traditional empirical methods, and improve the accuracy and real-time performance of chemical dosing control.

[0065] Achieve multi-parameter collaborative optimization control. Construct a quadratic polynomial model of the total phosphorus removal rate based on the interaction of magnetic powder, flocculant, and coagulant aid. Comprehensively consider the non-linear coupling relationship between different chemicals and hydraulic conditions, so that the dosing amount of chemicals can dynamically respond to the fluctuations of influent water quality, realize multi-variable collaborative regulation and optimization, improve the stability and reliability of the phosphorus removal efficiency, and avoid excessive dosing to control the phosphorus removal cost.

[0066] Reduce operating costs: Through accurate calculation and dynamic adjustment mechanisms, effectively avoid the phenomenon of excessive chemical dosing commonly existing in traditional automatic chemical dosing systems, reduce the usage of chemicals and magnetic powder, reduce the sludge production and treatment costs, and improve the economy of the entire phosphorus removal process.

[0067] Improve the automation level of the magnetic medium high-efficiency sedimentation tank system. Through the influent flowmeter 11, influent total phosphorus concentration analyzer 12, influent online suspended solids concentration analyzer 13, effluent flowmeter 41, effluent total phosphorus concentration analyzer 42, and effluent online suspended solids concentration analyzer 43, multi-point online monitoring of the sewage phosphorus removal process is carried out, and a closed-loop feedback control system is formed with the controller 5. Combining the preset effluent limit total phosphorus concentration and the effluent total phosphorus fluctuation value threshold, the chemical dosing amount is dynamically corrected, which can significantly improve the automation and intelligence level of the system, reduce the frequency of manual intervention, simplify the operation process, and enhance the convenience and efficiency of operation management.

[0068] In summary, the precise phosphorus removal control method provided in this technical solution has significantly improved in terms of phosphorus removal effect, operating cost control, and process automation control compared with the existing sewage sedimentation phosphorus removal technology, and is suitable for the construction of an automated control system for the advanced phosphorus removal process in sewage treatment plants.

[0069] By implementing the precise phosphorus removal control method in the magnetic medium high-efficiency sedimentation tank, in practical applications, the influent of the magnetic powder dosing tank 1 is the effluent of the previous secondary sedimentation tank. After long-term stable operation, the total phosphorus concentration of the effluent of the secondary sedimentation tank is 1.158 mg / L.

[0070] The magnetic powder used is Fe3O4, the flocculant is aluminum sulfate, and the coagulant aid is PAM.

[0071] Set the total phosphorus limit for the effluent to 0.35 mg / L and the suspended solid concentration in the effluent to 8 mg / L.

[0072] After conducting experiments, it is determined that the quadratic polynomial expression for the total phosphorus removal rate is: Total phosphorus removal rate = 8.875 + 2.01498×B - 181.83×C + 16.6745×A - 0.215×B×C + 0.00025×B×A + 9.95×C×A - 0.01433×B 2 + 282.8×C 2 - 2.572×A 2 ; Based on the data from the influent flowmeter 11 and the influent total phosphorus concentration analyzer 12, the controller 5 calculates the theoretical dosing amounts as A0 = 3.75 mg / L, B0 = 0.054 mg / L, and C0 = 0.39 mg / L respectively through the quadratic polynomial expression.

[0073] After processes such as magnetic powder dosing, mixing, flocculation, and sedimentation, the total phosphorus concentration and suspended solid concentration in the effluent collected by the effluent total phosphorus concentration analyzer 42 and the effluent on-line suspended solid concentration analyzer 43 are 0.195 mg / L and 4 mg / L respectively, meeting the effluent limit requirements and the effluent discharge limit requirements.

[0074] Among them, the theoretical total phosphorus removal rate predicted by the quadratic polynomial model of the total phosphorus removal rate is 81.65%, the actually measured total phosphorus removal rate is 81.11%, and the deviation rate is 0.6%.

[0075] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described.

Claims

1. A precise phosphorus removal control method based on a magnetic medium-added high-efficiency sedimentation tank, characterized in that: The method includes sequentially setting a magnetic powder dosing tank, a mixing tank, a flocculation tank and a high-efficiency sedimentation tank along the direction from sewage inlet to outlet, and setting a controller in the sedimentation phosphorus removal process room; in the precise phosphorus removal process, the controller collects data according to the precise phosphorus removal steps, calculates the dosage of the reagent, and controls the sequential addition of magnetic powder, flocculant and coagulant to the magnetic powder dosing tank, the mixing tank and the flocculation tank in a manner of dynamically limiting the dosage, so as to accurately control the dosage of magnetic powder, flocculant and coagulant to achieve precise phosphorus removal; Among them, the precise phosphorus removal steps are as follows: S1, real-time collection of influent parameters: an influent flow meter, an influent total phosphorus concentration analyzer and an influent online suspended solids concentration analyzer are set at the sewage inlet end of the magnetic powder dosing tank to respectively collect the influent flow, influent total phosphorus concentration and influent suspended solids concentration at the inlet end in real time; S2. Multivariate dynamic modeling to collaboratively calculate the dosage of reagents: Based on the interactive relationship between the dosage of magnetic powder A, the dosage of flocculant B, and the dosage of coagulant C, a quadratic polynomial model of total phosphorus removal rate was established; According to the influent flow rate, influent total phosphorus concentration and the preset effluent total phosphorus concentration limit value, the controller solves the quadratic polynomial model of total phosphorus removal rate and dynamically calculates the theoretical dosage A0, B0 and C0 of magnetic powder, flocculant and coagulant aid; S3, reagent addition: add magnetic powder to the magnetic powder addition tank according to A0, add flocculant to the mixing tank according to B0, and add coagulant to the flocculation tank according to C0. The reagents are mixed with the flowing sewage in each tank in turn, and flocculation is completed in the flocculation tank, and finally the sedimentation process is completed in the high-efficiency sedimentation tank; S4. Feedback adjustment of effluent parameters: an effluent flow meter, an effluent total phosphorus concentration analyzer and an effluent online suspended solids concentration analyzer are installed at the effluent end of the high-efficiency sedimentation tank to monitor the effluent total phosphorus concentration and effluent suspended solids concentration at the effluent end in real time; The controller compares the measured effluent total phosphorus concentration with the effluent total phosphorus concentration limit to determine whether the effluent is qualified: If the effluent total phosphorus concentration is greater than the effluent total phosphorus concentration limit, the effluent is judged to be unqualified. The effluent total phosphorus fluctuation value is obtained according to the deviation between the effluent total phosphorus concentration and the effluent total phosphorus concentration limit, and the dosage of A, B, and C is dynamically corrected with the preset adjustment range; If the effluent total phosphorus concentration is ≤ the effluent total phosphorus concentration limit, the effluent is judged to be qualified, and if the fluctuation range of the effluent total phosphorus fluctuation value is lower than the preset effluent total phosphorus fluctuation value threshold, the current dosage of the agent is maintained.

2. The precise phosphorus removal control method based on the magnetic medium high-efficiency sedimentation tank according to claim 1 is characterized in that: The quadratic polynomial model of total phosphorus removal rate is: Total phosphorus removal rate = a + b × B - c × C + d × A - e × B × C + f × B × A + g × C × A - h × B 2 +i×C 2 -j×A 2 ; Where a is the insurance coefficient, and b to j are the interaction influence coefficients of magnetic powder, flocculant, and coagulant aid.

3. The precise phosphorus removal control method based on the magnetic medium high-efficiency sedimentation tank according to claim 2 is characterized in that: The value of the insurance coefficient a is 8.80~8.95, which is used to compensate for the prediction error of the total phosphorus removal rate caused by the deviation of the influent data collection.

4. The precise phosphorus removal control method based on the magnetic medium high-efficiency sedimentation tank according to claim 2 is characterized in that: The coefficients b to j of the quadratic polynomial model of total phosphorus removal rate were determined through orthogonal experiments and multiple regression analysis, including: in the range of influent total phosphorus concentration of 1~4 mg / L, multiple groups of experiments were carried out by changing the dosage combination of A, B, and C, the total phosphorus removal rate data were recorded, and the least squares method was used to fit the values ​​of each coefficient b to j.

5. The precise phosphorus removal control method based on the magnetic medium high-efficiency sedimentation tank according to claim 1 is characterized in that: In step S4, the adjustment range is in a piecewise linear relationship with the fluctuation value of the effluent total phosphorus: when the fluctuation value of the effluent total phosphorus is ≤0.1 mg / L, the adjustment range is 2-5% of the theoretical dosage; When 0.1mg / L<total phosphorus fluctuation value of effluent ≤0.3mg / L, the adjustment range is 5~10% of the theoretical dosage; When the total phosphorus fluctuation value of the effluent is greater than 0.3 mg / L, the adjustment range is 10~15% of the theoretical dosage.

6. The precise phosphorus removal control method based on the magnetic medium high-efficiency sedimentation tank according to claim 1 is characterized in that: In step S3, the stirring intensity of the magnetic powder dosing tank, the mixing tank and the flocculation tank is linked with the dosage of A, B and C respectively: the stirring speed of the magnetic powder dosing tank is positively correlated with A, the stirring speed of the mixing tank is positively correlated with B, and the stirring speed of the flocculation tank is negatively correlated with C.

7. The precise phosphorus removal control method based on the magnetic medium high-efficiency sedimentation tank according to claim 1 is characterized in that: In step S2, the effluent total phosphorus concentration limit is 0.3-0.5 mg / L, and the controller automatically selects a preset dosing priority strategy according to the difference between the inlet total phosphorus concentration and the effluent total phosphorus concentration limit: When the total phosphorus concentration of the influent is greater than 3 mg / L, the dosage of flocculant B should be increased first; When the influent total phosphorus concentration is 1 mg / L≤≤3 mg / L, the synergistic dosage of magnetic powder A and coagulant aid C is optimized first.

8. The precise phosphorus removal control method based on a magnetic medium-added efficient sedimentation tank according to claim 2 is characterized in that: The inlet suspended solids concentration and outlet suspended solids concentration data from the inlet online suspended solids concentration analyzer and the outlet online suspended solids concentration analyzer are used to correct the interaction coefficients g and i in the quadratic polynomial model of total phosphorus removal rate in step S2: When the influent suspended solids concentration is > 50 mg / L, the coefficient g is increased by 10~20% and the coefficient i is decreased by 5~10%; When the inlet suspended solids concentration is ≤50mg / L, the coefficients g and i maintain the baseline value.

9. The precise phosphorus removal control method based on a magnetic medium-added efficient sedimentation tank according to claim 1 is characterized in that: The method also includes step S5, optimizing the magnetic powder recovery efficiency: the controller dynamically adjusts the dosage of A according to the magnetic powder content value of the bottom sludge of the high-efficiency sedimentation tank, so that the mass ratio of the recovered magnetic powder to the newly added magnetic powder is controlled at 1:0.3-1:0.

8.

10. The precise phosphorus removal control method based on a magnetic medium-added efficient sedimentation tank according to claim 2 is characterized in that: A pH sensor and a temperature sensor are also provided in the high-efficiency sedimentation tank; In step S2, the controller obtains the pH value and water temperature data in the high-efficiency sedimentation tank in real time based on the pH sensor and the temperature sensor; When the pH value is detected to be beyond the range of 6.5-8.0, the coefficients e and h in the quadratic polynomial model of total phosphorus removal rate are dynamically corrected according to the pH deviation value: If the pH deviation value is greater than 0.5, the coefficient e increases by 10~15% and the coefficient h decreases by 5~10%; If the pH deviation is less than -0.5, the coefficient e decreases by 10~15% and the coefficient h increases by 5~10%; At the same time, when the water temperature is lower than 10 °C, the coefficients b and d are increased by 20-30%, respectively, to compensate for the decrease in the flocculation reaction rate caused by low temperature.

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