COD (Chemical Oxygen Demand) analysis and control system for chlorine-containing high-salinity wastewater

Abstract

The invention discloses a chlorine-containing high-salinity wastewater COD analysis and control system, and particularly relates to the technical field of wastewater treatment process control and automation, the chlorine-containing high-salinity wastewater COD analysis and control system comprises an automatic sampling and chloride ion analysis unit, a heating digestion unit, an electronic titration metering unit, an end point judgment unit and a control and data processing unit; and the automatic sampling and chloride ion analysis unit is used for automatically collecting a water sample and measuring the chloride ion concentration of the water sample. According to the chlorine-containing high-salinity wastewater COD analysis and control system, the chlorine ions with the concentration similar to that of the water sample to be detected are doped in the built-in COD standard solution for synchronous measurement, the COD contribution equivalent of the chlorine ions is obtained in real time, the COD measured value of the actual water sample is dynamically corrected through the contribution equivalent, and the COD measured value of the water sample to be detected is obtained. The method effectively overcomes the problem that the measurement result is virtually high due to chloride ion oxidation in traditional COD measurement, improves the accuracy and reliability of chlorine-containing high-salinity wastewater COD measurement, and is suitable for complex water quality conditions with large chloride ion concentration fluctuation.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment process control and automation technology, and in particular to a COD analysis and control system for high-salt, chlorine-containing wastewater. Background Technology

[0002] Chemical oxygen demand (COD) is a key indicator for measuring the content of organic pollutants in water bodies. Accurate COD measurement is of great significance for the regulation of wastewater treatment processes and the monitoring of effluent quality. Currently, commonly used methods for COD determination mainly include the dichromate method and the rapid digestion spectrophotometric method. The dichromate method, as a national standard method, is applicable to various types of water samples, but its operation is complex and time-consuming, and requires the use of toxic and highly corrosive reagents such as mercuric sulfate and concentrated sulfuric acid, posing potential hazards to operators and the environment. While the rapid digestion spectrophotometric method is simple and fast, its resistance to interference is weak, especially under high chloride ion conditions, limiting its applicability. For high-chlorine, high-salinity wastewater, especially industrial wastewater with high chloride ion concentrations (such as wastewater from chemical, pharmaceutical, and seawater desalination industries), existing COD determination methods face significant challenges. On the one hand, chloride ions are oxidized in the strongly acidic potassium dichromate system, consuming the oxidant and leading to falsely high COD measurement results. On the other hand, chloride ions readily react with silver salt catalysts to form silver chloride precipitates, causing catalyst poisoning and affecting oxidation efficiency. Furthermore, in spectrophotometry, chloride ions form suspensions, interfering with the accurate measurement of absorbance. The existing technology suffers from the following problems: To overcome chloride ion interference, existing technologies typically employ sample dilution, chlorine correction, or potassium iodide-alkaline potassium permanganate methods. However, excessive dilution can increase measurement errors in low-concentration COD samples, while alternative methods such as chlorine correction suffer from cumbersome operation, limited applicability, or insufficient accuracy. The mercuric sulfate masking method requires the addition of large amounts of mercuric sulfate (HgSO4), resulting in high costs and mercury pollution risks, failing to meet environmental protection requirements. Dilution methods, when chloride ion concentrations >1000 mg / L, suffer from excessively high dilution factors leading to decreased analytical precision (relative deviation often >15%). The determination of the titration endpoint relies on visual judgment of color changes (yellow → blue-green → reddish-brown), making it susceptible to interference from water sample color and turbidity, resulting in large errors and low efficiency.

[0003] Furthermore, most existing methods rely on manual operation, making it difficult to achieve rapid and continuous online monitoring, and failing to meet the demands of modern wastewater treatment processes for real-time data feedback and automatic control. Meanwhile, machine learning algorithms, a branch of artificial intelligence, enable computer systems to "learn" patterns or rules from data and use these learning outcomes to make predictions or decisions about new data without explicit, line-by-line programming.

[0004] Among existing patent technologies, CN222125245U discloses a fully automatic intelligent COD analyzer, focusing on improving liquid addition efficiency and experimental speed, but it does not propose an effective correction scheme specifically for the interference problem of high chloride ion water samples. CN116067959A relates to a fully automatic method for determining seawater COD, which improves measurement accuracy by comparing image acquisition with colorimetric cards, but its correction method is still relatively traditional and lacks adaptability to the dynamic interference of chloride ions in complex water quality. CN108680716B provides a method for initial screening of COD in chlorinated wastewater, which is corrected by establishing a chloride ion contribution rate, and has the advantages of being fast and low-consumption. However, this method relies on a preset static correction model, which is difficult to cope with the dynamic interference caused by water quality fluctuations, and it does not form a closed-loop linkage with the process control system.

[0005] Therefore, the existing technology lacks a comprehensive analysis system that can automatically, accurately, and online measure the COD of high-salt, chlorine-containing wastewater, effectively correct for dynamic interference from chloride ions, and achieve intelligent linkage control with the treatment process. Summary of the Invention

[0006] The main objective of this invention is to provide a COD analysis and control system for high-salt, chlorine-containing wastewater, which can effectively solve the problems of inflated COD measurement values ​​caused by chloride ion interference, static lag in correction methods, and disconnect between monitoring and control links in existing technologies, making it impossible to achieve fully automated and intelligent regulation throughout the entire process.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A COD analysis and control system for high-salinity, chloride-containing wastewater includes: an automatic sampling and chloride ion analysis unit, a heating digestion unit, an electronic titration unit, an endpoint determination unit, and a control and data processing unit. The automatic sampling and chloride ion analysis unit automatically collects water samples and measures their chloride ion concentration. The heating digestion unit performs a heating digestion reaction on the water samples. The electronic titration unit automatically adds titrant to the digested water samples. The endpoint determination unit includes a computer vision color recognition system and an ultraviolet-visible spectral sensor, used to intelligently determine the titration endpoint through a multimodal approach. The control and data processing unit controls the coordinated operation of each unit and calculates the COD value based on the measured data. The system simultaneously measures chloride ions at a concentration similar to that of the water sample in a built-in COD standard solution to obtain the COD contribution equivalent of the chloride ions, and uses this contribution equivalent to dynamically correct the COD measurement value of the actual water sample. The corrected effluent COD analysis results are linked with an early warning system and process control devices to achieve early warning of exceeding standards and automatic adjustment of process parameters.

[0008] Preferably, the chloride ion analysis unit uses the electrode method and is equipped with a microfiltration system to pretreat the water sample; the heating digestion unit includes a set of four digestion vessels, which are used for the digestion and analysis of blank samples, chlorine-containing standard solutions, influent water samples and effluent water samples, respectively.

[0009] Preferably, the computer vision color recognition system identifies the change in solution color from yellow through blue-green to reddish-brown during titration using a trained color recognition model to determine the endpoint; when the vision system is interfered with by the color or turbidity of the water sample, the system can switch to using an ultraviolet-visible spectral sensor to determine the endpoint by detecting the absorbance inflection point at a wavelength of 600±20nm.

[0010] Preferably, the true concentration of the COD standard solution is set to... After doping with chloride ions, its theoretical concentration becomes The measured apparent concentration was The equivalent contribution of chloride ions is ( - The equivalent contribution of chloride ions per unit is ( - ) / ,in The measured chloride ion concentration; the apparent COD value measured from the actual water sample is... The corrected actual COD value According to the formula = + - The calculation yielded the result.

[0011] Preferably, the control and data processing unit further utilizes machine learning algorithms to establish a dynamic prediction model for chloride ion interference based on historical data of real-time measured chloride ion concentration and organic matter composition in wastewater, and optimizes the correction value to reduce errors.

[0012] The specific method is as follows: The actual COD concentration of the water sample... Actual chloride ion concentration in water samples COD concentration of standard sample after doping with chloride ions The theoretical concentration after doping with chloride ions and after doping with chloride ions and The ratio p will collect historical data. , , , p and reality The values ​​form a set I, and the actual concentration is estimated using the following formula: Formula 1: Actual water sample Equation 2: Theoretical concentration after doping with chloride ions Equation 3: COD concentration of the standard sample after doping with chloride ions Formula 4: in: Preferably, the system also integrates an ultrasonic cleaning system, which uses dilute hydrochloric acid with a concentration range of 2~5 mmol / L for acid washing, followed by cleaning with ultrapure water, and the cleaning endpoint is determined by monitoring the conductivity of the cleaning water.

[0013] Preferably, the electronic titration metering unit automatically reduces the titration rate when approaching the titration endpoint, and titrates by adding the titrant drop by drop.

[0014] Preferably, the system constitutes a closed-loop optimized control system, realizing automated operation and intelligent regulation of the entire process from monitoring to analysis, then to decision-making, and finally to control.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention provides a COD analysis and control system for high-salinity wastewater containing chloride. By simultaneously measuring chloride ions of similar concentration to the water sample being tested in a built-in COD standard solution, the COD contribution equivalent of chloride ions is obtained in real time. This contribution equivalent is then used to dynamically correct the COD measurement value of the actual water sample. This effectively overcomes the problem of falsely high measurement results caused by chloride ion oxidation in traditional COD measurement, improves the accuracy and reliability of COD measurement for high-salinity wastewater containing chloride, is suitable for complex water quality conditions with large fluctuations in chloride ion concentration, and does not require the addition of mercuric sulfate, thus avoiding heavy metal mercury pollution.

[0016] 2. This invention provides a COD analysis and control system for high-salt, chlorine-containing wastewater. It employs a multimodal endpoint determination strategy that combines a computer vision color recognition system with an ultraviolet-visible spectral sensor. This strategy can intelligently switch determination modes based on conditions such as water sample color and turbidity. When the vision system is interfered with, it automatically switches to spectral mode. By detecting the absorbance inflection point at a specific wavelength, it accurately determines the titration endpoint, effectively improving the anti-interference capability and adaptability of endpoint determination, and ensuring the consistency and stability of the analysis results.

[0017] 3. This invention provides a COD analysis and control system for high-salt, chlorine-containing wastewater. By constructing a closed-loop optimization control system from monitoring, analysis, decision-making to control, the corrected COD analysis results are linked in real time with the early warning system and process control device. Once COD exceeds the standard, the system automatically triggers an early warning and adjusts the process parameters, realizing the fully automated operation and intelligent optimization of the wastewater treatment process, improving treatment efficiency and water quality compliance rate. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the system architecture of the present invention. Detailed Implementation

[0019] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0020] Example 1: System Composition and Working Principle like Figure 1 As shown, a COD analysis and control system for high-salt, chlorine-containing wastewater is disclosed. This system mainly includes the following units: Automatic sampling and chloride ion analysis unit: This unit is responsible for automatically collecting water samples to be tested and determining their chloride ion concentration. Specifically, it includes an automatic sampling system with a sample arm, sample needle, sample tray, and drive system; a microfiltration system for filtering suspended solids in the water sample; and a chloride ion analysis device. The preferred method for chloride ion analysis is the electrode method, which is located at the rear end of the water sample flow cell.

[0021] Heating Digestion Unit: This unit is used for standardized digestion reactions of water samples. The digestion device has a square tray at the bottom and a circular heating plate at the top. The digestion tube is preferably made of quartz glass and is constructed as a conical flask at the bottom, with a straight cooling tube connected to the top. The cooling tube is equipped with an air-cooled or circulating water-cooled system to prevent volatilization. A system preferably includes four digestion vessels, which are used for the simultaneous digestion and analysis of blank samples, chlorine-containing COD standard solutions, influent water samples, and effluent water samples.

[0022] Electronic titration metering unit: This unit is used to accurately add titrant to the cooled digestion solution. A high-precision metering pump or syringe pump is used to achieve automatic and precise addition of the titrant. The titration rate is adjustable within the range of 1~20 mL / min, preferably 8~12 mL / min, and automatically reduces the rate near the titration endpoint, using a dropwise addition method to improve the accuracy of endpoint determination.

[0023] Endpoint Determination Unit: This unit is the core of the intelligent determination in this invention, employing a multimodal determination strategy combining a computer vision color recognition system and a UV-Vis spectral sensor. The computer vision color recognition system mainly includes an infrared variable-focus camera, auxiliary light source, image acquisition card, image processor, and computing platform. Its core is a color recognition model trained on a large number of samples, capable of accurately identifying the change in solution color from yellow through blue-green to reddish-brown during titration, and determining reddish-brown as the titration endpoint. UV-Vis spectral sensor-assisted determination: The preferred detection wavelength is 600±20 nm. When the water sample has high chroma or turbidity, interfering with the visual system, the system can automatically switch to spectral mode. By detecting the absorbance change curve at this wavelength with the addition of titrant, the inflection point is identified to accurately determine the titration endpoint.

[0024] Control and Data Processing Unit: As the brain of the system, this unit integrates the CNC system, computing platform, storage device and control communication interface. It is responsible for coordinating the orderly operation of each unit, collecting data, executing the core COD calculation and correction algorithm, and communicating with external early warning and process control systems.

[0025] Ultrasonic cleaning unit: This unit is used to automatically clean the sample inlet tubing, digestion flasks, titration area, etc. during each analysis interval to prevent cross-contamination. The cleaning process consists of two steps: first, acid cleaning is performed using dilute hydrochloric acid with a concentration of 2~5 mmol / L, followed by rinsing with ultrapure water. The conductivity of the cleaning water is monitored online, and cleaning is stopped when it is basically consistent with the conductivity of the inlet water to ensure system cleanliness.

[0026] Example 2: Detailed Analysis Process and Correction Method The specific workflow of the system is as follows: Automatic sampling and chloride ion determination: After the system is started, the automatic sampling system first collects the high-salt, chloride-containing wastewater sample to be tested. After pretreatment by the microfiltration system, the sample enters the flow cell, where the chloride ion concentration is measured by the chloride ion electrode. ; Simultaneous preparation and digestion: The system processes four samples in parallel: Blank sample: using pure water. Chlorine-containing COD standard solution: using known true concentration. The COD standard solution is prepared by adding a quantitative amount of sodium chloride standard solution to make its chloride ion concentration match that of the water sample being tested. Similarly, its theoretical COD concentration after dilution becomes Influent sample: Raw wastewater containing high levels of chloride and salinity to be tested. Effluent sample: Effluent from the wastewater treatment system to be tested; 5 mL of potassium dichromate solution, 2 mL of mercuric sulfate solution, and 10 mL of sulfuric acid-silver sulfate solution are automatically added sequentially to each of the four 10 mL samples. The digestion tube is then moved to the heating digestion unit and heated for digestion at the set temperature. The digestion time range is 20–120 minutes, preferably 60 minutes. If the system detects through computer vision that the solution turns bright green during digestion, or if the concentration is determined to be too high based on preset conditions (C~COD~+0.25*C~Cl-~≥800mg / L), a dilution treatment is required.

[0027] Cooling and Transfer: After digestion, activate the air-cooling system to cool the digest to room temperature. Then, automatically add 45 mL of pure water from the top of the cooling tube for dilution. Subsequently, transfer the liquid from the bottom conical flask to the central titration area.

[0028] Titration and Endpoint Determination: Three drops of ferroin indicator are automatically added to the digestion solution in the titration zone. The electronic titration unit is then activated, and titration is performed using a ferrous ammonium sulfate standard solution with concentrations C~B~. During the titration, the endpoint determination unit operates in real time. By default, a computer vision color recognition system is used to monitor the solution color change. When the solution turns reddish-brown, the titration endpoint is determined, and the volume of ferrous ammonium sulfate consumed is recorded. If the vision system is interfered with, it automatically switches to UV-Vis spectral mode, determining the endpoint based on the absorbance inflection point at 600±20 nm. The volume of blank sample consumed is recorded. , volume of chlorine-containing standard solution consumed The actual water sample consumption volume V~n~.

[0029] COD Calculation and Dynamic Correction: The control and data processing unit performs the following calculations: Apparent COD value calculation: The formula for calculating apparent COD after blank value correction is: C = 800 × C~B~ × (V - V0) The apparent concentration of the chlorine-containing standard solution is C2 = 800 × C~B~ × (V1 - V0). The apparent concentration of the actual water sample is Cn = 800 × CB × (Vn - V0). Chloride ion contribution equivalent calculation: Chloride ion contribution equivalent Δ = - Unit chloride ion contribution equivalent K = Δ / Actual COD correction value for water sample: The corrected COD value of the actual water sample is Cnr = Cn + C1 - C2 = Cn - Δ The core of this correction method lies in obtaining the specific interference level (Δ) of chloride ions under the current water quality conditions by simultaneously measuring a chlorine-containing standard solution, and subtracting it from the apparent measurement value of the water sample to obtain a COD result that is closer to the true value.

[0030] Early warning and process linkage control: The corrected COD value (C~nr~) of the effluent sample is automatically compared with the preset discharge standard or process control setpoint. If an exceedance is detected, the control and data processing unit immediately sends an alarm signal to the central control early warning system through the control cabinet. At the same time, it sends control commands to the process control systems such as the dosing pump, aeration system, and sludge discharge valve, dynamically adjusting process parameters such as dosing dosage and hydraulic retention time. This forms a closed-loop optimization system from monitoring to analysis, then to decision-making, and finally to control, ensuring that the effluent consistently meets the standards.

[0031] The following two specific embodiments further illustrate the implementation effects of the present invention, but the scope of protection of the present invention is not limited thereto.

[0032] Example 3: Analysis of wastewater with low chloride ion concentration The effluent from the secondary biological treatment tank of a chemical plant's wastewater treatment plant has a COD concentration ranging from 10 to 50 mg / L, and the chloride ion concentration is measured to be 252.0 mg / L. A COD standard solution with a mass concentration of C0 = 40 mg / L is taken as a control and diluted with a sodium chloride standard solution containing 2000 mg / L chloride ions. After dilution, a chloride ion concentration of 252.0 mg / L and a theoretical COD concentration of C1 = 35.0 mg / L are obtained. This solution is then measured, and the apparent value is C2 = 88.1 mg / L. Therefore, the chloride ion contribution equivalent is 88.1 - 35.0 = 53.1 mg / L, and the unit chloride ion contribution equivalent is 53.1 / 252.0 = 0.21. The apparent value of the chlorine-containing wastewater was 78.1 mg / L, so the corrected value was 78.1-53.1=25.0 mg / L. The value was determined by the masked titration method according to the national standard HJ 828-2017 "Determination of Chemical Oxygen Demand in Water - Potassium Dichromate Method" and was 23.7 mg / L. The relative deviation between the two methods was 5.48%.

[0033] Example 4: Analysis of wastewater with high chloride ion concentration A high-salt solution from a chemical plant, with a COD concentration ranging from approximately 60 to 120 mg / L, was measured to contain 3440 mg / L of chloride ions. A control solution containing 100 mg / L of COD standard substance was diluted with a sodium chloride standard solution containing 20000 mg / L of chloride ions. This resulted in a chloride-containing standard solution with a chloride ion concentration of 3440 mg / L and a theoretical COD concentration of C1 = 82.8 mg / L. This solution was then measured, yielding an apparent value of C2 = 748.0 mg / L. Therefore, the chloride ion contribution equivalent was 678.0 - 82.8 = 595.2 mg / L, and the unit chloride ion contribution equivalent was 595.2 / 3440 = 0.173. The measured value of chlorine-containing wastewater is 673.0, so the correction value is 673.0-595.2=77.8mg / L; the measured value is 80.8mg / L by the masked titration method of the national standard HJ 828-2017 "Determination of Chemical Oxygen Demand in Water by Potassium Dichromate Method". The relative deviation between the two methods is 3.71%.

[0034] The working principle of this COD analysis and control system for chlorine-containing high-salt wastewater will be explained in detail below.

[0035] like Figure 1 As shown, the system first collects water samples and measures their chloride ion concentration through an automatic sampling and chloride ion analysis unit. Then, a heating digestion unit performs a standard digestion reaction on the water samples. After digestion, an electronic titration unit precisely adds titrant to the water samples, while an endpoint determination unit intelligently determines the titration endpoint using a computer vision color recognition system or an ultraviolet-visible spectral sensor. The control and data processing unit calculates the apparent COD value based on the titration data and dynamically obtains the COD contribution equivalent of chloride ions by simultaneously measuring a COD standard solution with a similar chloride ion concentration, thus correcting the COD value of the actual water samples. The specific method is as follows: The actual COD concentration of the water sample... Actual chloride ion concentration in water samples COD concentration of standard sample after doping with chloride ions The theoretical concentration after doping with chloride ions and after doping with chloride ions and The ratio p will collect historical data. , , , p and reality The values ​​form a set I, and the actual concentration is estimated using the following formula: Formula 1: Actual water sample Equation 2: Theoretical concentration after doping with chloride ions Equation 3: COD concentration of the standard sample after doping with chloride ions Formula 4: in: Ultimately, the corrected COD results are linked with the early warning system and process control devices to achieve early warning of exceeding the standard and automatic adjustment of process parameters, forming a closed-loop automated system from monitoring, analysis, decision-making to control.

[0036] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A COD analysis and control system for high-salinity, chlorine-containing wastewater, characterized in that: include: The system comprises an automatic sampling and chloride ion analysis unit, a heating digestion unit, an electronic titration unit, an endpoint determination unit, and a control and data processing unit. The automatic sampling and chloride ion analysis unit automatically collects water samples and measures their chloride ion concentration. The heating digestion unit performs a heating digestion reaction on the water samples. The electronic titration unit automatically adds titrant to the digested water samples. The endpoint determination unit includes a computer vision color recognition system and an ultraviolet-visible spectral sensor, used to intelligently determine the titration endpoint through a multimodal approach. The control and data processing unit controls the coordinated operation of each unit and calculates the COD value based on the measured data. The system synchronously measures chloride ions at a concentration similar to that of the water sample being tested by doping a built-in COD standard solution, obtaining the COD contribution equivalent of the chloride ions, and uses this contribution equivalent to dynamically correct the COD measurement value of the actual water sample. The corrected effluent COD analysis results are linked with the early warning system and process control device to achieve early warning of exceeding standards and automatic adjustment of process parameters. The control and data processing unit executes the following correction algorithm: The true concentration of the COD standard solution is set to... After doping with chloride ions, its theoretical concentration becomes The measured apparent concentration was The equivalent contribution of chloride ions is ( - The equivalent contribution of chloride ions per unit is ( - ) / ,in The measured chloride ion concentration; the apparent COD value measured from the actual water sample is... The corrected actual COD value According to the formula = + - The calculation yielded the result.

2. The COD analysis and control system for high-salinity, chlorine-containing wastewater according to claim 1, characterized in that: The chloride ion analysis unit uses the electrode method and is equipped with a microfiltration system to pretreat the water sample; the heating digestion unit includes a set of four digestion vessels, which are used for the digestion and analysis of blank samples, chlorine-containing standard solutions, influent water samples and effluent water samples, respectively.

3. The COD analysis and control system for high-salinity, chlorine-containing wastewater according to claim 1, characterized in that: The computer vision color recognition system identifies the change in solution color from yellow through blue-green to reddish-brown during titration using a trained color recognition model to determine the endpoint. When the vision system is interfered with by the color or turbidity of the water sample, the system can switch to an ultraviolet-visible spectral sensor to determine the endpoint by detecting the absorbance inflection point at a wavelength of 600±20nm.

4. The COD analysis and control system for high-salinity, chlorine-containing wastewater according to claim 4, characterized in that: The control and data processing unit further utilizes machine learning algorithms to establish a dynamic prediction model for chloride ion interference based on historical data of real-time measured chloride ion concentration and organic matter composition in wastewater, and optimizes the correction value to reduce errors. The specific method is as follows: The actual COD concentration of the water sample... Actual chloride ion concentration in water samples COD concentration of standard sample after doping with chloride ions The theoretical concentration after doping with chloride ions and after doping with chloride ions and The ratio p will collect historical data. , , , p and reality The values ​​form a set I, and the actual concentration is estimated using the following formula: Formula 1: Actual water sample Equation 2: Theoretical concentration after doping with chloride ions Equation 3: COD concentration of the standard sample after doping with chloride ions Formula 4: in: 。 5. The COD analysis and control system for high-salinity chlorine-containing wastewater according to claim 1, characterized in that: The system also integrates an ultrasonic cleaning system, which uses dilute hydrochloric acid with a concentration range of 2~5 mmol / L for acid washing, followed by ultrapure water cleaning, and the cleaning endpoint is determined by monitoring the conductivity of the cleaning water.

6. The COD analysis and control system for high-salinity chlorine-containing wastewater according to claim 1, characterized in that: The electronic titration metering unit automatically reduces the titration rate when approaching the titration endpoint, and titrates by adding the titrant drop by drop.

7. A COD analysis and control system for high-salinity, chlorine-containing wastewater according to any one of claims 1 to 7, characterized in that: The system constitutes a closed-loop optimized control system, realizing automated operation and intelligent regulation of the entire process from monitoring to analysis, then to decision-making, and finally to control.

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