Intelligent control method and system for adding chlorine dioxide into coagulation clarification tank

Abstract

The invention belongs to the technical field of water treatment, and particularly relates to an intelligent control method and system for adding chlorine dioxide into a coagulation clarification tank. Comprising the following steps: S1, obtaining a model of total concentration distribution of residual chlorine in a coagulative precipitation tank; s2, under a stable environmental condition, based on multi-period historical data, obtaining an empirical function relationship between concentration reduction values of different indexes and the concentration of residual chlorine in the coagulative precipitation tank; s3, measuring COD (Chemical Oxygen Demand), ammonia nitrogen and escherichia coli community number indexes of inlet water at the moment t, and calculating a difference value between the indexes and an outlet water standard, namely an inlet water load; s4, the optimal residual chlorine concentration meeting the treatment standard at the current period and with the lowest chemical consumption is calculated; and S5, dynamically updating model parameters. The system has the beneficial effects that the control precision is high, the working condition is monitored in real time in the operation process, the model is matched in a targeted manner, and the effluent quality is accurately controlled. By taking the water outlet indexes of main objects of the water plant as control targets, a better control effect can be obtained, and the dependence of operators on expert experience can be reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water treatment, and particularly relates to an intelligent control method and system for chlorine dioxide dosing of a coagulation and clarification tank. BACKGROUND

[0002] After the microbial theory was proved in the mid-19th century, it was widely known that chemical disinfectants could inactivate microorganisms in water to reduce the spread of water-borne infectious diseases. According to the World Health Organization's report on the safety of drinking water, chemical disinfection methods are widely used in centralized and decentralized water supply at home and abroad. In the early 20th century, chlorine was found to be an effective disinfectant for drinking water. Chlorine disinfection mainly works through hypochlorous acid. Chlorine enters the water and undergoes hydrolysis and ionization reactions to form hypochlorous acid, which penetrates the surface of negatively charged bacteria and penetrates the cell wall to enter the bacteria, destroying the bacterial enzyme system through oxidation and causing the bacteria to die. Liquid chlorine is the most commonly used chlorine disinfectant. Chlorine has strong killing ability for microorganisms, has sustained disinfection effect, is easy to use, and has low disinfection cost, so chlorine disinfection is the most widely used disinfection method at present.

[0003] Chlorine disinfectants mainly include liquid chlorine, chlorine dioxide, chloramine, and sodium hypochlorite. Chlorine dioxide is a broad-spectrum and highly effective disinfectant with good killing effect on pathogenic microorganisms in water and fast action, and can effectively inactivate Giardia and Cryptosporidium. It is a mainstream water treatment disinfectant in China at present.

[0004] However, the disinfection effect of chlorine dioxide is affected by temperature and pH. Chlorine dioxide produces inorganic disinfection byproducts ClO2 - , which has potential toxicity to the human body. At the same time, chlorine dioxide gas is unstable and difficult to store and transport, and needs to be prepared on site for use, which has high production cost. Therefore, it is an urgent need in the water treatment industry to achieve precise dosing control of chlorine dioxide to meet the requirements of sterilization and disinfection while minimizing the negative effects of byproducts and saving energy and reducing consumption.

[0005] At present, the automatic dosing control of chlorine dioxide is mainly based on traditional proportional-integral-derivative (PID) control, which uses the residual chlorine in the effluent as the target for feedback adjustment. However, the residual chlorine in the effluent is affected by many factors, and the chlorine addition process is a typical large time lag process. The feedback control method of PID cannot adapt to changes in the environment and water quality, nor can it cope with the time lag problem of the chlorine addition environment itself, ultimately leading to unstable residual chlorine in the effluent and easy to cause large fluctuations. It has become a consensus that PID control cannot achieve optimal control of chlorine addition. At present, chlorine addition control research focuses on model predictive control (MPC), and the following research is representative: Research I: Use ControlLogix system as the lower machine, embed model predictive control (MPC) module in the lower machine; use historical data of water plant in the model predictive control module to establish prediction model, train the model in the simulation of actual application, and integrate the empirical formula of water plant in the control module to realize precise control of the chlorination system.

[0006] Research II: Use "feedforward prediction + dynamic feedback" control logic. Real-time feedback through residual chlorine online sensor, combined with neural network algorithm to predict pipe network water quality changes, to realize precise control of the chlorination system.

[0007] However, factors affecting the residual chlorine of effluent include not only reagents, influent flow, but also uncontrollable environmental factors such as climate, temperature, season, and the influence of influent water quality. The above method uses the idea of introducing feedforward control for precise chlorination, but cannot dynamically track changes in environmental factors, accurately assess chlorine dioxide consumption efficiency, and dynamically adjust, which is not intelligent control. SUMMARY

[0008] The purpose of the present application is to provide an intelligent control method and system for coagulation and clarification pool chlorine dioxide dosing, which can accurately assess the chlorine dioxide consumption efficiency by dynamically tracking the environmental impact factors during the chlorine dioxide dosing process, and can realize precise adjustment and control of residual chlorine, while meeting the requirements of sterilization and disinfection, and minimizing the negative impact of by-products and saving energy.

[0009] The technical solution of the present application is as follows: An intelligent control method for coagulation and clarification pool chlorine dioxide dosing, comprising the following steps: S1: Obtain a model of the overall residual chlorine concentration distribution in the coagulation and sedimentation tank; S2: Under stable environmental conditions, based on multi-period historical data, obtain the empirical function relationship between the concentration reduction value of different indicators and the residual chlorine concentration in the coagulation and sedimentation tank; S3: At time t, measure the COD, ammonia nitrogen, and coliform group number indicators of the influent, and calculate the difference between them and the effluent standard, i.e. the influent load; S4: Calculate the optimal residual chlorine concentration that meets the treatment standard and has the lowest reagent consumption; S5: Dynamically update the model parameters.

[0010] The step S1 includes calculating the overall residual chlorine concentration in the coagulation and sedimentation tank as follows: Use the position variables of the length, width and height of the coagulation and sedimentation tank to express the form (2) Estimate the overall residual chlorine concentration using the residual chlorine concentrations of a limited number of measurement points in the coagulation and sedimentation tank (3) The form expressed by the position variables of the length, width and height of the coagulation sedimentation tank (4) Wherein, represents the overall residual chlorine concentration of the coagulation sedimentation tank, and V represents the total volume of the coagulation sedimentation tank, represents the volume variable of the coagulation sedimentation tank, which is a function of the position of the residual chlorine measuring point, and the range is 0~V, that is, at the inlet of the coagulation sedimentation tank, , at the outlet of the coagulation sedimentation tank, , L, W and H represent the length, width and height of the coagulation sedimentation tank, respectively, and l, w and h represent the position variables of the length, width and height of the coagulation sedimentation tank, represents the residual chlorine concentration at different positions in the coagulation sedimentation tank, using the multi-point measurement method, combining formula (4), the residual chlorine concentrations measured by each measuring point are weighted and averaged by taking the proportion of the space volume covered between the measuring points to the entire tank volume as the weight, to estimate the overall residual chlorine concentration .

[0011] The formula used in step S2 to measure the removal amount of impurities is as follows Wherein: t represents the sampling time at the water inlet; T represents the time interval required from the water inlet sampling point to the water outlet sampling point, which is measured according to different water plant conditions; , , respectively represent the change amount between the concentrations of COD, ammonia nitrogen, coliform group number at t time and the concentrations of effluent at t+T time; , , respectively represent the influent concentrations of COD, ammonia nitrogen and coliform group number at t time; , , respectively represent the effluent concentrations of COD, ammonia nitrogen and coliform group number at t+T time, historical data is obtained through multiple measurements, the overall residual chlorine concentration is calculated, and a relationship database of residual chlorine concentration and impurity removal amount is established: Accordingly, the empirical function relationship between the overall residual chlorine concentration estimate and the impurity removal amount is obtained: Wherein: represents the overall dissolved oxygen concentration of the coagulation sedimentation tank at time t; , , respectively represent the concentration reduction values of COD, ammonia nitrogen, and coliform group after treatment under a certain residual chlorine level .

[0012] The specific calculation process in step S3 is as follows: Whether the residual chlorine concentration change needs to adjust the setting value is related to the following factors: Influent flow rate; Influent water quality Water temperature, pH Assuming that ① and ③ are constant, the dynamic load at time t has the following formula: , , respectively represent the concentration values that COD, ammonia nitrogen, and coliform group should be reduced to reach the effluent standard at time t, i.e., the load at time t; , , respectively represent the influent concentrations of COD, ammonia nitrogen, and coliform group at time t; , , respectively represent the effluent standards of COD, ammonia nitrogen, and coliform group.

[0013] In step S4, for each sampling time t, the optimal residual chlorine concentration , The drug consumption required by the chlorine dioxide dosing system to maintain the residual chlorine concentration is , and the drug consumption and the residual chlorine concentration are positively correlated: To find the lowest drug consumption that can meet the effluent standard, find the lowest residual chlorine concentration that meets the effluent standard, i.e., solve the following problem: Wherein, , , These represent the concentration values ​​that COD, ammonia nitrogen, and E. coli community number should be reduced to meet the effluent standards at time t, respectively, i.e., the load at time t. , , These represent the removal amounts of COD, ammonia nitrogen, and Escherichia coli community number at the residual chlorine level during the time period t to t+T, respectively. , Let these be the lower and upper bounds of the residual chlorine concentration in the coagulation sedimentation tank, respectively. The four constraints in the above problem can be transformed into: Therefore, there is Find: in, , , These represent the influent concentrations of COD, ammonia nitrogen, and E. coli community number at time t, respectively. , , These represent the effluent standards for COD, ammonia nitrogen, and E. coli colony count, respectively. This represents the optimal residual chlorine concentration at time t.

[0014] In step S5, the empirical function relationship between residual chlorine concentration, COD, ammonia nitrogen, and E. coli colony count removal rate is dynamically updated, i.e., the parameters of the empirical function are updated, in the following way: exist The relationship between residual chlorine concentration and impurity removal rate was obtained in real time. in: express Overall residual chlorine concentration at any given time; express The level of impurities in the water decreases continuously from the time it enters the water to the time it exits the water. if, ; Then the new sample data will replace the old sample data: wherein: represents residual chlorine concentration at the time point; represents residual chlorine concentration at the time point; represents reduction level of impurities from water inlet to water outlet at the time point; represents reduction level of impurities from water inlet to water outlet at the time point.

[0015] An intelligent control system for coagulation and clarification pool chlorine dioxide dosing, comprising a remote intelligent management unit, a water plant site communication cabinet, an intelligent chlorine dioxide preparation and dosing control cabinet, a chlorine dioxide dosing flowmeter, a hydrochloric acid storage tank, a sodium chlorate storage tank and a monitoring instrument group, the remote intelligent management unit comprises an intelligent chlorine dioxide dosing calculation server, a central control switch and a central control host computer connected in sequence, the monitoring instrument group comprises an inlet flowmeter, an inlet pH / temperature monitor, an inlet COD analyzer, an inlet ammonia nitrogen analyzer, an inlet coliform bacteria monitor, a coagulation and sedimentation pool residual chlorine monitor, an outlet COD analyzer, an outlet ammonia nitrogen analyzer, an outlet coliform bacteria monitor and an outlet residual chlorine monitor, the instruments in the monitoring instrument group are connected to the communication cabinet through control cables, and the monitoring end is used for measuring various water quality parameters in the process.

[0016] The intelligent chlorine dioxide dosing calculation server 1 is a general-purpose computer installed with the method as claimed in claims 1-7, the central control switch is a network switch deployed in the central control room of the water plant, the central control host computer is a general-purpose computer installed with the original central control host program of the water plant, and the water plant site communication cabinet is used for receiving and sending the measurement results of the inlet flowmeter, the inlet pH / temperature monitor, the inlet COD analyzer, the inlet ammonia nitrogen analyzer, the inlet coliform bacteria monitor, the coagulation and sedimentation pool residual chlorine monitor, the outlet COD analyzer, the outlet ammonia nitrogen analyzer, the outlet coliform bacteria monitor and the outlet residual chlorine monitor.

[0017] The inlet flowmeter, the inlet pH / temperature monitor, the inlet COD analyzer, the inlet ammonia nitrogen analyzer and the inlet coliform bacteria monitor in the monitoring instrument group are arranged at the water distribution well position, the coagulation and sedimentation pool residual chlorine monitor in the monitoring instrument group is arranged at the coagulation and sedimentation pool, and the outlet COD analyzer, the outlet ammonia nitrogen analyzer, the outlet coliform bacteria monitor and the outlet residual chlorine monitor in the monitoring instrument group are arranged at the outlet of the water purification treatment device.

[0018] The hydrochloric acid storage tank and the sodium chlorate storage tank are connected to the intelligent chlorine dioxide preparation and dosing control cabinet through a medicament pipeline, the intelligent chlorine dioxide preparation and dosing control cabinet prepares chlorine dioxide solution through mixing of hydrochloric acid and sodium chlorate, and the chlorine dioxide solution is delivered to the coagulation and sedimentation pool dosing point through the medicament pipeline.

[0019] The beneficial effects of the present application are: Control accuracy: based on Bayesian principles, using big data tools for modeling, fully considering the relevant influencing factors in the regulation process, real-time monitoring of working conditions during operation, targeted matching of models, and ensuring accurate control of water quality.

[0020] System usability: taking the main water indicators of the water plant (COD, ammonia nitrogen, coliform group count, residual chlorine...) as the control target, better control effect can be achieved, without manual decision intervention, reducing the dependence of operation personnel on expert experience, and facilitating operation and management.

[0021] Running stability: based on MPC (model predictive control), artificial intelligence algorithms are introduced to automatically evaluate the effect of each round of regulation, and when the predicted results deviate from the actual results, real-time adaptive correction is performed to ensure that the regulation mechanism is effective in the long term.

[0022] Promotion: MPC (model predictive control) under the support of big data tools and artificial intelligence algorithms can be quickly deployed in water plants of different water quality, different environment and different equipment types, and system debugging can be completed within 1-2 months to realize stable operation. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 An intelligent control method flow chart for coagulation and clarification pool chlorine dioxide dosing provided by the present application; Figure 2 An intelligent control device schematic diagram for coagulation and clarification pool chlorine dioxide dosing provided by the present application; Figure 3 A schematic diagram of the distribution of residual chlorine in the coagulation and sedimentation tank; Figure 4 A schematic diagram of the relationship between COD removal chlorine and residual chlorine concentration; In the figure: 1 intelligent chlorine dioxide dosing calculation server, 2 central control switch, 3 water plant field communication cabinet, 301 inlet flow meter, 302 inlet pH / temperature monitor, 303 inlet COD analyzer, 304 inlet ammonia nitrogen analyzer, 305 inlet coliform monitor, 306 coagulation and sedimentation tank residual chlorine monitor, 307 outlet COD analyzer, 308 outlet ammonia nitrogen analyzer, 309 outlet coliform monitor, 310 outlet residual chlorine monitor, 4 central control host computer, 5 intelligent chlorine dioxide preparation and dosing control cabinet, 6 chlorine dioxide dosing flow meter, 7 hydrochloric acid tank, 8 sodium chlorate tank. DETAILED DESCRIPTION

[0024] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0025] For example, Figure 1As shown, a kind of coagulation clarifier intelligent control method of chlorine dioxide dosing, comprising the following steps: S1: obtain the model of the overall concentration distribution of residual chlorine in coagulation sedimentation tank Mainly through the residual chlorine concentration estimation of multiple measuring points, in different processes, under the condition that internal and external reflux are in steady state, according to the flow rate, flow rate and other fluid mechanics principles, the simulation model of residual chlorine distribution in coagulation sedimentation tank is constructed.

[0026] As Figure 3 Shown, along the length direction of coagulation sedimentation tank, residual chlorine concentration is different at different positions. In fact, the distribution of residual chlorine in water is not only related to the position in the length direction of coagulation sedimentation tank, but also the size of coagulation sedimentation tank can be simplified as L*W*H, in different areas Δl × Δw × Δh in three-dimensional space, the concentration of residual chlorine is not the same.

[0027] The overall residual chlorine concentration is calculated as follows: Theoretical formula of overall residual chlorine concentration of coagulation sedimentation tank: (1) The form expressed by the position variables of length, width and height (2) In practice, the formula used for calculation estimates the overall residual chlorine concentration by using the residual chlorine concentration of a limited number of measuring points (3) The form expressed by the position variables of length, width and height (4) Wherein, The overall residual chlorine concentration of coagulation sedimentation tank, V represents the total volume of coagulation sedimentation tank, The volume variable of coagulation sedimentation tank is a function of the position of residual chlorine measuring point, and the range is 0~V, that is, at the inlet of coagulation sedimentation tank, At the outlet of coagulation sedimentation tank, L, W and H represent the length, width and height of coagulation sedimentation tank respectively, l, w and h represent the position variables of length, width and height of coagulation sedimentation tank respectively, The residual chlorine concentration at different positions in coagulation sedimentation tank, in the embodiment of the present application, multiple point measurement method is used, combined with formula (4), the proportion of the space volume covered between measuring points to the whole pool volume (Δ Δ l Δ w ) is used as weight, and the residual chlorine concentration h Measured by each measuring point CL (l, w, h) Is weighted average, and the overall residual chlorine concentration Is estimated.

[0028] S2: Under stable environmental conditions (constant coagulation sedimentation tank backflow ratio), based on multi-period historical data, the empirical function relationship between the concentration reduction value of different indicators and the residual chlorine concentration in the coagulation sedimentation tank is obtained; The removal amount of impurities is measured using the following formula Wherein: t represents the sampling time at the inlet; T represents the time interval required from the inlet sampling point to the outlet sampling point, which is measured according to different water plant conditions; , , respectively represent the change amount between the concentrations of COD, ammonia nitrogen, coliform group number at t time and the concentration at t+T time at the outlet; 、 、 respectively represent the inlet concentrations of COD, ammonia nitrogen, coliform group number at t time; 、 、 respectively represent the outlet concentrations of COD, ammonia nitrogen, coliform group number at t+T time.

[0029] After multiple measurements, a large amount of historical data is obtained, and the overall residual chlorine concentration calculated in S1 is used to establish a relationship database between the residual chlorine concentration ( ) and the removal amount of impurities: Accordingly, the empirical function relationship between the overall residual chlorine concentration estimate and the removal amount of impurities can be obtained: Wherein: represents the overall dissolved oxygen concentration of the coagulation sedimentation tank at t time; 、 、 respectively represent the concentration reduction values of COD, ammonia nitrogen, coliform group number after treatment under a certain residual chlorine level ( ).

[0030] S3: At t time, the COD, ammonia nitrogen (NH3-N), coliform group number (CFU) and other indicators of the inlet water are measured, and the difference between the outlet standard and the inlet load is calculated, that is, the specific calculation steps are as follows: The change of residual chlorine concentration is completed through the chlorine dioxide dosing system, and whether the setting value needs to be adjusted is related to the following factors: Inflow rate Inflow water quality Water temperature, pH Assuming that ①③ are constant, the dynamic load at time t has the following formula: , , COD, ammonia nitrogen, and coliform group numbers at time t that should be reduced to meet the effluent standard, i.e., the load at time t; , , COD, ammonia nitrogen, and coliform group numbers at time t that should be reduced to meet the effluent standard, i.e., the load at time t; , , COD, ammonia nitrogen, and coliform group numbers at time t that should be reduced to meet the effluent standard, i.e., the load at time t;

[0031] S4: Calculate the optimal residual chlorine concentration that meets the processing standard and has the lowest drug consumption For each sampling time t, find the optimal residual chlorine concentration .

[0032] Assuming that the drug consumption required by the chlorine dioxide dosing system to maintain the residual chlorine concentration is Since drug consumption and residual chlorine concentration are positively correlated: Therefore, finding the lowest drug consumption that meets the effluent standard is to find the lowest residual chlorine concentration that meets the effluent standard, i.e., to solve the following problem: where, , , COD, ammonia nitrogen, and coliform group numbers at time t that should be reduced to meet the effluent standard, i.e., the load at time t; , , COD, ammonia nitrogen, and coliform group numbers at time t that should be reduced to meet the effluent standard, i.e., the load at time t; , The lower limit and upper limit of the residual chlorine concentration in the coagulation sedimentation tank, respectively, and the empirical values are 0.2 mg / L and 1 mg / L.

[0033] The four constraints in the above problem are converted to: Therefore, It is obtained: Where, , , Influent concentration of COD, ammonia nitrogen, and coliform group at time t; , , The effluent standards of COD, ammonia nitrogen, and coliform group, The optimal residual chlorine concentration at time t.

[0034] S5: Dynamically update model parameters In order to adapt to the dynamic environmental conditions, the model is based on the concept of "data novelty", dynamically update the empirical function relationship between residual chlorine concentration and COD, ammonia nitrogen, and coliform group removal rate, that is, update the parameters of the empirical function, in the following way: At , the relationship between residual chlorine concentration and impurity removal amount is obtained, Where: Indicates the overall residual chlorine concentration at time t; Indicates the impurity reduction level from the influent to the effluent at time t.

[0035] With the acquisition of new sample data, if the residual chlorine concentration at is , and the residual chlorine concentration at is . Approximately the same, but the measured pollutant removal amount is quite different, then check the environmental variables-temperature, PH value-if the environmental variables are also approximately the same, according to the data novelty rule, use new data to replace old data, that is: If, ​​ Then, the new sample sh helmet is used to replace the old sample data: Wherein: represents the residual chlorine concentration at the moment; represents the residual chlorine concentration at the moment; represents the impurity reduction level from water inlet to water outlet at the moment; represents the impurity reduction level from water inlet to water outlet at the moment. Wherein, CL represents the residual chlorine concentration, and Δ(CL) represents the pollutant removal amount under a certain residual chlorine concentration.

[0036] As shown in Figure 2 , according to the above control method, an intelligent control system for chlorine dioxide dosing of coagulation and clarification tank is constructed, which comprises a remote intelligent management unit, a water plant site communication cabinet 3, an intelligent chlorine dioxide preparation and dosing control cabinet 5, a chlorine dioxide dosing flowmeter 6, a hydrochloric acid storage tank 7, a sodium chlorate storage tank 8 and a monitoring instrument group. Wherein, the remote intelligent management unit comprises an intelligent chlorine dioxide dosing calculation server 1, a central control switch 2 and a central control host computer 4 connected in sequence, and the monitoring instrument group comprises an inlet flowmeter 301, an inlet pH / temperature monitor 302, an inlet COD analyzer 303, an inlet ammonia nitrogen analyzer 304, an inlet E. coli monitor 305, a coagulation and sedimentation tank residual chlorine monitor 306, an outlet COD analyzer 307, an outlet ammonia nitrogen analyzer 308, an outlet E. coli monitor 309 and an outlet residual chlorine monitor 310. The instruments in the monitoring instrument group are respectively connected to the communication cabinet 3 through control cables, and the monitoring end is used for measuring various water quality parameters in the process.

[0037] The intelligent chlorine dioxide dosing calculation server 1, the central control switch 2, the central control host computer 4 and the water plant site communication cabinet 3 adopt existing products. The intelligent chlorine dioxide dosing calculation server 1 is a general-purpose computer installed with the software algorithm of the present application. The central control switch 2 is a network switch deployed in the central control room of the water plant. The central control host computer 4 is a general-purpose computer installed with the original central control host program of the water plant. The water plant site communication cabinet 3 is the original communication cabinet of the water plant site, which contains PLC, relay and other electronic components, and is used for receiving and sending the measurement results of the inlet flowmeter 301, the inlet pH / temperature monitor 302, the inlet COD analyzer 303, the inlet ammonia nitrogen analyzer 304, the inlet E. coli monitor 305, the coagulation and sedimentation tank residual chlorine monitor 306, the outlet COD analyzer 307, the outlet ammonia nitrogen analyzer 308, the outlet E. coli monitor 309 and the outlet residual chlorine monitor 310.

[0038] The intelligent chlorine dioxide preparation and dosing control cabinet 5 is a customized product, and contains industrial control host and PLC electronic elements. The industrial control host is installed with a software interface for human-computer interaction, and the PLC is used to receive the chlorine dioxide dosing amount setting instruction sent by the central control upper host 4 via the central control switch 2, and to command the chlorine dioxide dosing flow meter 6, the hydrochloric acid storage tank 7, the sodium chlorate storage tank 8 and other devices to complete the adjustment and execution of chlorine dioxide dosing according to the chlorine dioxide dosing amount setting instruction.

[0039] The communication cabinet 3 and the intelligent chlorine dioxide preparation and dosing control cabinet 5 are connected to the remote intelligent management unit through optical cables for network data connection. Specifically, the communication cabinet 3 and the intelligent chlorine dioxide preparation and dosing control cabinet 5 are connected to the intelligent chlorine dioxide dosing calculation server 1 and the central control upper host 4 respectively through the central control switch 2. When the information flow is large, the central control switch can effectively stabilize the data flow, and at the same time, it is more convenient for centralized management of information. The intelligent chlorine dioxide preparation and dosing control cabinet 5 is connected to the chlorine dioxide dosing flow meter 6 through a control cable; the hydrochloric acid storage tank 7 and the sodium chlorate storage tank 8 are connected to the intelligent chlorine dioxide preparation and dosing control cabinet 5 through a reagent pipeline. After the intelligent chlorine dioxide preparation and dosing control cabinet 5 prepares the chlorine dioxide solution, the chlorine dioxide solution is transported to the chlorine dioxide dosing point of the coagulation sedimentation tank through the reagent pipeline.

[0040] The inside of the communication cabinet 3 is connected to the monitoring instrument group through a control cable, which is used to collect monitoring parameters in each water treatment unit in the process flow in real time, and to integrate and upload the collected data.

[0041] The present application is applied to a water purification treatment device, which comprises a water distribution well, a coagulation sedimentation tank, a sand filter tank, a carbon filter tank and a clear water tank.

[0042] The water inlet flow meter 301, the water inlet pH / temperature monitor 302, the water inlet COD analyzer 303, the water inlet ammonia nitrogen analyzer 304 and the water inlet coliform bacteria monitor 305 in the monitoring instrument group are arranged at the water distribution well.

[0043] The coagulation sedimentation tank residual chlorine monitor 306 in the monitoring instrument group is arranged at the coagulation sedimentation tank.

[0044] The water outlet COD analyzer 307, the water outlet ammonia nitrogen analyzer 308, the water outlet coliform bacteria monitor 309 and the water outlet residual chlorine monitor 310 in the monitoring instrument group are arranged at the water outlet of the water purification treatment device.

[0045] The hydrochloric acid storage tank 7 and the sodium chlorate storage tank 8 are connected to the intelligent chlorine dioxide preparation and dosing control cabinet 5 through a reagent pipeline. The intelligent chlorine dioxide preparation and dosing control cabinet 5 prepares chlorine dioxide solution by mixing hydrochloric acid and sodium chlorate, and transports the chlorine dioxide solution to the dosing point of the coagulation sedimentation tank through the reagent pipeline.

[0046] The device is configured as follows: when the central control host receives the collected data sent by the communication cabinet 3, the intelligent chlorine dioxide dosing calculation server 1 sends a data acquisition request to the central control host 4 at the same time through the central control switch 2. The central control host 4 returns the collected data to the intelligent chlorine dioxide dosing calculation server 1, and then the intelligent chlorine dioxide dosing calculation server 1 calculates the chlorine dioxide dosing amount according to the current water quality and generates corresponding instructions to send to the intelligent chlorine dioxide preparation and dosing control cabinet 5 to complete the transmission and execution of the instructions.

[0047] The intelligent chlorine dioxide preparation and dosing control cabinet 5 is configured to open or close the dosing pipeline after receiving the instructions from the intelligent chlorine dioxide dosing calculation server 1. The hydrochloric acid and sodium chlorate delivered by the hydrochloric acid storage tank 7 and the sodium chlorate storage tank 8 are mixed to form a chlorine dioxide aqueous solution, and the internal dosing pump and the external chlorine dioxide flow meter 6 are controlled by the PID interlocking control to complete the execution and control of the chlorine dioxide dosing amount of the coagulation and sedimentation tank.

[0048] The system of the present application can realize the following functions: According to the impurity load to be removed, the residual chlorine in the effluent is dynamically adjusted; according to different environmental factors (influent temperature, pH value), the relationship between different residual chlorine in the effluent and impurity removal load is determined; the corresponding relationship between residual chlorine in the effluent and impurity removal load is dynamically updated using data novelty.

[0049] The system of the present application has the following operation process: I. Data acquisition and preliminary processing The monitoring instrument group (influent flow meter 301, influent pH / temperature monitor 302, influent COD analyzer 303, influent ammonia nitrogen analyzer 304, influent E. coli monitor 305, coagulation and sedimentation tank residual chlorine monitor 306, effluent COD analyzer 307, effluent ammonia nitrogen analyzer 308, effluent E. coli monitor 309, effluent residual chlorine monitor 310) is installed in the corresponding processing unit to monitor the key parameters in the water treatment process in real time.

[0050] The 4-20 mA signals (i.e. collected data) generated by the monitoring instrument group are first transmitted to the communication cabinet 3 through the control cable. The data processing module inside the communication cabinet 3 further converts these signals into optical signals to improve the efficiency and accuracy of data transmission.

[0051] II. Data transmission and distribution The optical signal obtained in step one is transmitted from the communication cabinet 3 to the central control switch 2 through an optical cable. After receiving the optical signal, the central control switch 2 distributes the data to the central control host computer 4 through a network cable. At the same time, the intelligent chlorine dioxide dosing calculation server 1 sends a data acquisition application to the central control host computer 4 through the central control switch 2 to obtain the current water quality data.

[0052] III. Data processing and instruction generation The intelligent chlorine dioxide dosing calculation server 1 further calculates and analyzes the received collected data to obtain the chlorine dioxide dosing amount set value at the current time, and transmits it to the intelligent chlorine dioxide preparation and dosing control cabinet 5 in the form of an instruction through the central control switch 2.

[0053] IV. Instruction execution and chlorine dioxide dosing After receiving the instruction transmitted by the intelligent chlorine dioxide dosing calculation server 1, the intelligent chlorine dioxide preparation and dosing control cabinet 5 converts it into a control signal and sends it to the internal electromagnetic valve. The internal electromagnetic valve opens or closes the reagent pipeline according to the received instruction, mixes the hydrochloric acid and sodium chlorate delivered from the hydrochloric acid storage tank 7 and the sodium chlorate storage tank 8 to produce chlorine dioxide aqueous solution, and completes the execution control of the chlorine dioxide dosing amount of the coagulation and sedimentation tank through the PID interlocking control of the internal dosing pump and the external chlorine dioxide flowmeter 6.

[0054] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed in the present application can be easily thought of by those skilled in the art, and should be covered within the protection scope of the present application.

Claims

1. An intelligent control method for coagulation and clarification pool chlorine dioxide dosing, characterized in that, It comprises the following steps: S1: obtaining the model of the overall concentration distribution of residual chlorine in the coagulation sedimentation tank; S2: under stable environmental conditions, based on multi-period historical data, obtaining the empirical function relationship between the concentration reduction value of different indicators and the residual chlorine concentration in the coagulation sedimentation tank; S3: at time t, measuring the COD, ammonia nitrogen, and coliform group number indicators of the influent, and calculating the difference between them and the effluent standard, i.e. the influent load; S4: calculating the optimal residual chlorine concentration that meets the treatment standard and has the lowest drug consumption at the current period; S5: dynamically updating the model parameters.

2. The intelligent control method for chlorine dioxide dosing in coagulation sedimentation tank according to claim 1, characterized in that, The step S1 comprises calculating the overall residual chlorine concentration in the coagulation sedimentation tank as follows: using the position variables of the length, width, and height of the coagulation sedimentation tank to express the form （2） using the residual chlorine concentrations of a limited number of measurement points in the coagulation sedimentation tank to estimate the overall residual chlorine concentration （3） using the position variables of the length, width, and height of the coagulation sedimentation tank to express the form （4） Wherein, represents the overall residual chlorine concentration of the coagulation sedimentation tank, V represents the total volume of the coagulation sedimentation tank, represents the volume variable of the coagulation sedimentation tank, which is a function of the position of the residual chlorine measuring point, and the range is 0~V, that is, at the inlet of the coagulation sedimentation tank, , at the outlet of the coagulation sedimentation tank, , L, W, H represent the length, width and height of the coagulation sedimentation tank respectively, and l, w, h represent the position variables of the length, width and height of the coagulation sedimentation tank respectively, represents the residual chlorine concentration at different positions in the coagulation sedimentation tank, using a multi-point measurement method, combining formula (4), taking the proportion of the space volume covered between the measuring points to the entire tank volume as the weight, the residual chlorine concentrations measured by each measuring point are weighted and averaged to estimate the overall residual chlorine concentration .

3. The method for intelligent control of chlorine dioxide dosage in coagulation sedimentation tank according to claim 1, characterized in that: The step S2 uses the following formula to measure the removal amount of impurities Wherein: t represents the sampling time of the water inlet; T represents the time interval required from the water inlet sampling point to the water outlet sampling point, which is measured according to different water plant conditions; , , respectively represent the change amount between the concentrations of COD, ammonia nitrogen, coliform group number at t time and the concentration of the water outlet at t+T time; 、 、 respectively represent the influent concentrations of COD, ammonia nitrogen, coliform group number at t time; 、 、 respectively represent the effluent concentrations of COD, ammonia nitrogen, coliform group number at t+T time, the historical data is obtained through multiple measurements, the overall residual chlorine concentration is calculated, and the relationship database of residual chlorine concentration ( ) and impurity removal amount is established:​ Accordingly, the empirical function relationship between the overall residual chlorine concentration estimate and the impurity removal amount is obtained: Wherein: represents the overall dissolved oxygen concentration of the aerobic tank at time t; , , respectively represent the concentration reduction values of COD, ammonia nitrogen, and coliform group after treatment under a certain residual chlorine level .

4. The method for intelligent control of chlorine dioxide dosage in coagulation sedimentation tank according to claim 1, characterized in that, The specific calculation process in step S3 is as follows: Whether the change of residual chlorine concentration needs to adjust the setting value is related to the following factors: influent flow rate; influent water quality water temperature, pH Assuming that ① and ③ are constant, the dynamic load at time t has the following formula: , , COD, ammonia nitrogen, and coliform group colony count at time t, respectively, the concentration value that should be reduced to meet the effluent standard, i.e. the load at time t; , , represent the influent concentration of COD, ammonia nitrogen, and coliform group colony count at time t, respectively; , , represent the effluent standard of COD, ammonia nitrogen, and coliform group colony count, respectively.

5. The intelligent control method for chlorine dioxide dosing in coagulation sedimentation tank according to claim 1, characterized in that: Said step S4 consists in finding, for each sampling time t, the optimal residual chlorine concentration , The drug consumption required by the chlorine dioxide dosing system to maintain the residual chlorine concentration is The drug consumption and the residual chlorine concentration are positively correlated. To find the lowest drug consumption that can meet the effluent standard, find the lowest residual chlorine concentration that meets the effluent standard, i.e. solve the following problem: wherein, , , respectively represent the concentration value of COD, ammonia nitrogen, and coliform group colony count to be reduced to reach the effluent standard at time t, i.e., the load at time t; , , respectively represent the removal amount of COD, ammonia nitrogen, and coliform group colony count under the residual chlorine level in the period from t to t+T; , are the lower limit and the upper limit of the residual chlorine concentration in the coagulation sedimentation tank, and the four constraint conditions in the above problem are converted into: Therefore, The step S5 dynamically updates the empirical function relationship between the residual chlorine concentration and the removal rates of COD, ammonia nitrogen, and coliform group number, i.e. updates the parameters of the empirical function, in the following manner: Wherein, , , respectively represent the influent concentration of COD, ammonia nitrogen, and coliform group colony count at time t; , , respectively represent the effluent standard of COD, ammonia nitrogen, and coliform group colony count, indicates the optimal residual chlorine concentration at time t.

6. The intelligent control method for chlorine dioxide dosing in coagulation sedimentation tank according to claim 1, characterized in that: If In The relationship between the residual chlorine concentration and the amount of impurities removed was obtained at the moment, wherein: represents the overall residual chlorine concentration at the time; represents the level of impurity reduction from water-in to water-out at the time, then use the new sample data to replace the old sample data: ； It comprises a remote intelligent management unit, a water plant site communication cabinet, an intelligent chlorine dioxide preparation and dosing control cabinet, a chlorine dioxide dosing flow meter, a hydrochloric acid storage tank, a sodium chlorate storage tank, and a monitoring instrument group. The remote intelligent management unit comprises an intelligent chlorine dioxide dosing calculation server, a central control switch, and a central control host computer connected in sequence. The monitoring instrument group comprises an influent flow meter, an influent pH / temperature monitor, an influent COD analyzer, an influent ammonia nitrogen analyzer, an influent coliform bacteria monitor, a coagulation sedimentation tank residual chlorine monitor, an effluent COD analyzer, an effluent ammonia nitrogen analyzer, an effluent coliform bacteria monitor, and an effluent residual chlorine monitor. The instruments in the monitoring instrument group are connected to the communication cabinet through control cables, and the monitoring end is used to measure various water quality parameters in the process. wherein: represents residual chlorine concentration at the time point; represents residual chlorine concentration at the time point; represents reduction level of impurities from the time point of water entry to water exit; represents reduction level of impurities from the time point of water entry to water exit.

7. An intelligent control system for chlorine dioxide dosing in coagulation and sedimentation tanks, characterized by: The intelligent chlorine dioxide dosing calculation server 1 is a general-purpose computer installed with the method of claims 1-7. The central control switch is a network switch deployed in the central control room of the water plant. The central control host computer is a general-purpose computer installed with the original central control host program of the water plant. The water plant site communication cabinet is used to receive and send the measurement results of the influent flow meter, the influent pH / temperature monitor, the influent COD analyzer, the influent ammonia nitrogen analyzer, the influent coliform bacteria monitor, the coagulation sedimentation tank residual chlorine monitor, the effluent COD analyzer, the effluent ammonia nitrogen analyzer, the effluent coliform bacteria monitor, and the effluent residual chlorine monitor.

8. The intelligent control system for chlorine dioxide dosing of coagulation and sedimentation tank as claimed in claim 7 wherein: ​ 9. The intelligent control system for chlorine dioxide dosing in a coagulation clarifier as described in claim 7, characterized in that: The water inflow flowmeter, the water inflow pH / temperature monitor, the water inflow COD analyzer, the water inflow ammonia nitrogen analyzer and the water inflow E. coli monitor in the monitoring instrument group are arranged at the water distribution well position, the coagulation sedimentation tank residual chlorine monitor in the monitoring instrument group is arranged at the coagulation sedimentation tank, and the water outflow COD analyzer, the water outflow ammonia nitrogen analyzer, the water outflow E. coli monitor and the water outflow residual chlorine monitor in the monitoring instrument group are arranged at the water outflow port of the water purification treatment device.

10. The intelligent control system for chlorine dioxide dosing in a coagulation clarifier as described in claim 7, characterized in that: The hydrochloric acid storage tank and the sodium chlorate storage tank are connected with the intelligent chlorine dioxide preparation and dosing control cabinet through a medicament pipeline, the intelligent chlorine dioxide preparation and dosing control cabinet prepares chlorine dioxide solution through mixing of hydrochloric acid and sodium chlorate, and the chlorine dioxide solution is transported to the dosing point of the coagulation sedimentation tank through the medicament pipeline.

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