Refractory organic wastewater pretreatment system based on multi-stage plasma synergistic oxidation

Abstract

The invention discloses a degradation-resistant organic wastewater pretreatment system based on multi-stage plasma synergistic oxidation, belongs to the technical field of wastewater advanced oxidation treatment, and adopts a multi-stage plasma discharge synergistic oxidation treatment mechanism to directionally match with a three-stage gradient oxidation process, and adopts differentiated mechanical structure, discharge mode and reaction atmosphere design. According to the present invention, the multi-stage directional oxidation is performed on the different stages of the pollutant degradation, the possible treatment blind area existing in the single oxidation path is effectively eliminated, the degradation thoroughness and the mineralization rate of the pollutants are substantially improved, and the multi-source data real-time monitoring of the water quality and the process state is integrated based on the three-stage gradient oxidation process so as to provide the multi-stage directional oxidation effect. Cooperative analysis and multi-objective optimization solution are carried out through the process decision module, discharge parameters and reaction atmosphere of each stage of reaction unit are dynamically and cooperatively regulated and controlled, an efficient, stable and low-consumption cooperative treatment effect is achieved, and stable and reliable pretreatment guarantee is provided for subsequent biological treatment.

Description

Technical Field

[0001] This invention relates to the field of advanced wastewater oxidation treatment technology, and more specifically, to a pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation. Background Technology

[0002] Recalcitrant organic wastewater mainly originates from industries such as chemical, pharmaceutical, printing and dyeing, and pesticides. It is characterized by high concentrations of highly toxic and recalcitrant organic pollutants (such as benzene compounds, halogenated hydrocarbons, and polycyclic aromatic hydrocarbons). This wastewater generally has a stubborn molecular structure, chemical stability, strong biological toxicity, ecological inhibition, extremely poor biodegradability, and unusable carbon sources. These characteristics directly hinder the application of mainstream biological treatment methods.

[0003] In the field of advanced oxidation pretreatment of recalcitrant organic wastewater, ozone-based catalytic oxidation technology has attracted much attention due to its strong oxidizing properties. Existing technologies (such as CN118954765A) combine pressurized dissolved gas with highly efficient catalysts to improve the dissolution, mass transfer, and utilization efficiency of ozone, achieving some progress. However, such technical solutions still have several inherent drawbacks: 1. Its oxidation capacity is highly dependent on a single oxidant (ozone) and its catalytic derivatives: When faced with complex and structurally diverse recalcitrant organic compounds, a single oxidation pathway is often selective, resulting in low oxidation efficiency for some stubborn pollutants and making it difficult to achieve comprehensive and thorough degradation of pollutants. 2. The energy input of this technical route is not precisely matched with the degradation requirements of pollutants: the system enhances the effect by increasing the overall ozone concentration and pressure, and the energy consumption is concentrated in gas preparation and compression. It lacks a gradient energy design based on the step-by-step decomposition of pollutant molecular structure, resulting in low energy utilization efficiency. In addition, the system operating parameters rely heavily on preset parameters, making it difficult to respond quickly and accurately to changes in water quality. It has insufficient resistance to shock loads and there is a risk that residual oxidant in the effluent will affect subsequent biological treatment.

[0004] Therefore, based on the practical challenges of organic wastewater treatment, a pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation is proposed. Summary of the Invention

[0005] The purpose of this invention is to address practical technical deficiencies. It provides a pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation, which achieves efficient decomposition and mineralization of recalcitrant organic matter through the synergistic effect of multi-stage plasma discharge and various active oxides.

[0006] The objective of this invention can be achieved through the following technical solution: a pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation, comprising a primary reaction unit, a secondary reaction unit, a tertiary reaction unit connected in series along the wastewater treatment flow direction, and an intelligent synergistic control center connected to each level of reaction unit, wherein each level of reaction unit is configured to perform differentiated oxidation treatment tasks; The intelligent collaborative control center is equipped with a water quality data acquisition module, a reaction status monitoring module, and a process decision-making module. The water quality data acquisition module is used to collect water quality data, including raw wastewater data and effluent data after treatment by each reaction unit. The reaction status monitoring module is used to acquire process status data of each reaction unit. The process decision module receives water quality data and process status data, and is configured to perform the following operations: Initial path decision: Based on the raw wastewater data, the pre-stored process decision engine is invoked to select the initial process path for each reaction unit; Target feature extraction: In the continuous reaction process, key performance indicators of each reaction unit at each level are extracted from water quality data to form first-level, second-level, and third-level target datasets; Target comparison and optimization: The target datasets at each level are compared with the pre-stored standard target data at each level of the outlet to obtain the target deviation of each reaction unit. For the target deviation that reaches the upper limit, the corresponding process control model is called. Under the premise of satisfying the initial process path constraints, combined with the process status data, the optimal set of process parameters is obtained through multi-objective optimization. Command generation and execution: Dynamic control commands are generated based on the process parameter set, and the discharge parameters and reaction atmosphere of each stage of the reaction unit are adjusted according to the dynamic control commands.

[0007] Furthermore, the primary reaction unit includes a vertical cylindrical reactor, a DBD electrode assembly, a grounding electrode, a primary water distribution device for atomizing wastewater and spraying it downwards into the reaction chamber, and a primary gas distribution device for introducing the first reaction gas into the bottom of the reaction chamber.

[0008] Furthermore, the secondary reaction unit includes a vertical tower-shaped reactor, an alloy barbed wire high-voltage electrode array, a honeycomb-shaped grounded cathode cylinder, a secondary gas distribution device located at the bottom of the tower for introducing the second reaction gas, and a secondary water distribution device located at the top of the reactor and connected to the outlet of the primary reaction unit.

[0009] Furthermore, the three-stage reaction unit includes a vertical combined reactor and a gas-liquid distribution plate installed therein. The gas-liquid distribution plate divides the vertical combined reactor into a sliding arc reaction chamber and a fixed bed catalytic chamber. The sliding arc reaction chamber is equipped with a pair of blade electrodes arranged in a V-shape. Below the pair of blade electrodes is a three-stage gas distribution nozzle for injecting high-speed gas flow into the electrode gap. The three-stage gas distribution nozzle is externally connected to a three-stage water distribution pipe that connects to the outlet of the two-stage reaction unit.

[0010] Furthermore, the process decision engine selects the initial process path based on the combination of key parameters in the original wastewater quality data. The combination of key parameters includes at least: the intensity level of the characteristic pollutant's ultraviolet absorbance (UV254), chemical oxygen demand (COD) concentration, total organic carbon (TOC) value, pH value, dissolved ozone (DO3) concentration, and biotoxicity indicators.

[0011] Furthermore, in the process of target feature extraction, the extracted primary target dataset includes the removal load of macromolecular characteristic pollutants, the extracted secondary target dataset includes pH value and TOC removal rate, and the extracted tertiary target dataset includes biotoxicity indicators and oxidant residue indicators.

[0012] Furthermore, the process status data includes electrical process data and material process data. The electrical process data includes the real-time output voltage, output current, and instantaneous discharge power from the high-voltage power supply of each reaction unit. The material process data includes the real-time gas mass flow rate and pressure leading to the gas inlet branch of each reaction unit, as well as the temperature of key points inside each reactor.

[0013] Furthermore, the process control model called during the target comparison and optimization process is an independent multi-objective optimization control model corresponding to each stage of the reaction unit; The optimization and control model of the first-stage reaction unit aims to minimize energy consumption and maximize the removal load of macromolecular characteristic pollutants, with discharge stability and target B / C ratio as constraints. The output adjustment parameters include, but are not limited to: the frequency and duty cycle of the high-voltage power supply, and the oxygen concentration and flow rate of the oxygen-enriched air. The optimization model of the secondary reaction unit aims to maximize the TOC removal rate and minimize the reaction temperature rise, with the target pH range and the equipment temperature limit as constraints. Its output adjustment parameters include, but are not limited to: the peak voltage and repetition frequency of the pulse corona discharge, and the pure oxygen supply rate. The optimization model of the three-stage reaction unit aims to minimize biotoxicity and oxidant residue, and is constrained by ensuring that the pH value of the effluent is within the suitable range for subsequent biological treatment. Its output adjustment parameters include, but are not limited to: the switching command for the type of gas introduced and the input power of the sliding arc discharge.

[0014] Compared with the prior art, the advantages of this invention are: 1. This invention abandons the traditional technical route that relies on a single external oxidant. Instead, it adopts a multi-stage plasma discharge synergistic oxidation treatment mechanism. It uses a three-stage gradient oxidation process to generate hydroxyl radicals, high-energy electrons, ozone, ultraviolet light, high-temperature active particles, and other active substances in situ and on demand. This process targets different stages of pollutant degradation (macromolecules, small molecules, and stubborn fragments), matching energy fields and oxidation mechanisms to carry out "segmented attacks." This forms a "production line" for the targeted degradation of pollutants, enabling "segmented, targeted, and relay-style" attacks on different types of pollutants with different chemical bond energies. This effectively eliminates the "treatment blind spots" that may exist in a single oxidation path, and significantly improves the thoroughness of pollutant degradation and mineralization rate.

[0015] 2. Based on the three-stage gradient oxidation process, this invention integrates real-time monitoring of multi-source data on water quality and process status, and performs multi-objective optimization through the process decision module. It dynamically and collaboratively controls the discharge parameters and reaction atmosphere at each stage, enabling the system to intelligently sense water quality fluctuations, automatically identify oxidation treatment anomalies, and re-optimize resource allocation. It has strong resistance to shock loads and adaptive capabilities, ensuring long-term stable and reliable treatment effects, while minimizing the ineffective addition and residue of oxidant. Attached Figure Description

[0016] Figure 1 This is a system principle block diagram of the present invention; Figure 2 A flowchart of the method for multi-objective optimization and control instructions in the process decision module of the present invention; Figure 3 This is a perspective view showing the coordinated operation of the reaction units at each stage of the present invention; Figure 4 This is a cross-sectional schematic diagram of each stage of the reaction unit of the present invention.

[0017] Explanation of the labels in the diagram: 1. Primary reaction unit; 11. Vertical cylindrical reactor; 12. DBD electrode assembly; 13. Grounding electrode; 14. Primary water distribution device; 15. Primary gas distribution device; 2. Secondary reaction unit; 21. Vertical tower reactor; 22. Alloy barbed wire high-voltage electrode array; 23. Honeycomb grounded cathode cylinder; 24. Secondary water distribution device; 25. Secondary gas distribution device; 3. Three-stage reaction unit; 31. Vertical combined reactor; 32. Blade electrode; 33. Three-stage gas distribution nozzle; 34. Three-stage water distribution pipe. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] Example 1: Addressing the shortcomings of traditional single-oxidation pretreatment technologies, a novel pretreatment system is proposed that overcomes the limitations of single oxidants, achieves synergistic effects through multiple mechanisms, utilizes energy in a cascade manner, and possesses intelligent adaptive capabilities. This system aims to solve the treatment challenges of recalcitrant organic wastewater more economically, efficiently, and stably. The specific technical solution is as follows: This invention discloses a pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation. Please refer to [link / reference]. Figures 1-4 It includes primary, secondary, and tertiary reaction units connected in series along the wastewater treatment flow direction, as well as an intelligent collaborative control center that is independently connected to each reaction unit. Each reaction unit is configured to perform differentiated oxidation treatment tasks.

[0020] Specifically, the primary reaction unit 1 includes a vertical cylindrical reactor 11, a DBD electrode assembly 12 arranged parallel to the axial direction of the reaction chamber of the vertical cylindrical reactor 1, a grounding electrode 13 opposite to the DBD electrode assembly 12, a primary water distribution device 14 for atomizing wastewater and spraying it downward into the reaction chamber, and a primary gas distribution device 15 for introducing the first reaction gas to the bottom of the reaction chamber. The DBD electrode assembly includes a high-voltage electrode and a dielectric layer that wraps the high-voltage electrode. The grounding electrode 13 is usually a stainless steel mesh or cylindrical electrode that is closely attached to the inner wall of the vertical cylindrical reactor 11. It forms a radial discharge electric field with the axially arranged high-voltage electrodes, which runs through the entire vertical gas-liquid mixing zone. The primary water distribution device 14 is a uniformly distributed pressure atomizing nozzle. The primary gas distribution device 15 adopts an annular gas distribution pipe or a microporous diffuser. The primary reaction unit employs a dielectric barrier discharge (DBD) structure and is configured to introduce air or oxygen-enriched air through a primary gas distribution device 15. The air or oxygen-enriched air is uniformly introduced into the reaction chamber from bottom to top at a certain flow rate. The microporous structure helps to form a fine, dispersed bubble flow. When the gas flows through the discharge gap between the high-voltage electrode and the dielectric layer, it is bombarded by high-energy electrons, generating primary oxidants OH (strong non-selective oxidation) and O3 (selective oxidation). The wastewater is sprayed downward in the form of extremely fine droplets, which come into countercurrent contact and violently collide with the upward-moving gas in a plasma-filled annular reaction space. This process breaks down and breaks the chains of large-molecule recalcitrant organic matter in the wastewater. The primary oxidant removes target pollutants, such as large-molecule complex organic matter (benzene series, dye molecules, polycyclic aromatic hydrocarbons), and some biological inhibitors. The output after the reaction is wastewater containing small-molecule organic acids (formic acid, acetic acid), aldehydes, ketones, some CO2, and primary products containing unreacted O3 in the tail gas.

[0021] The secondary reaction unit 2 includes a vertical tower reactor 21, an alloy barbed wire high-voltage electrode array 22 located on the central axis of the vertical tower reactor 21, a honeycomb grounded cathode cylinder 23 arranged around the alloy barbed wire high-voltage electrode array 22, a secondary water distribution device 24 located at the top of the reactor and spraying downwards, and a secondary gas distribution device 25 located at the bottom of the tower for countercurrent flow of the second reaction gas. The secondary reaction unit employs a reinforced pulsed corona discharge (PCD) structure, configured to introduce pure oxygen or ozone-containing gas via a secondary gas distribution device. This generates a secondary oxidant primarily composed of high-density hydroxyl radicals and high-energy electrons, deeply mineralizing the small-molecule intermediates produced in the primary treatment. The vertical tower-shaped reactor also features a packing layer above the alloy barbed wire high-voltage electrode array, employing a counter-current contact design. Wastewater flows uniformly downwards from the top of the tower through the packing layer (such as Pall rings). Discharge occurs in the gas-liquid mixing zone below the packing layer. The main target pollutants are small-molecule organic acids, alcohols, aldehydes, and other primary products. The outputs after the reaction are wastewater with a COD removal rate of 60%-80%, mineralized products (CO2, water), and tail gas containing CO. 2， And a small amount of unreacted O2.

[0022] The third-stage reaction unit 3 includes a gas-liquid distribution plate installed inside a vertical combined reactor 31. The gas-liquid distribution plate divides the vertical combined reactor 31 into a sliding arc reaction chamber and a fixed bed catalytic chamber connected sequentially from bottom to top. A pair of blade electrodes 32 arranged in a V-shape are provided in the sliding arc reaction chamber. Below the pair of blade electrodes is a third-stage gas distribution nozzle 33 for injecting high-speed gas flow into the electrode gap. The third-stage gas distribution nozzle 33 is externally connected to a third-stage water distribution pipe 34 that connects to the outlet of the second-stage reaction unit 2. The electrodes are arranged in an involute shape with their tips at the bottom and their roots at the top. An adjustable discharge gap of 1-3 mm is left between the tips of the two electrodes. One electrode serves as a high-voltage electrode, and its root is connected to an external high-voltage power supply through a high-voltage insulating sleeve on the side wall of the reactor. The other electrode serves as a grounding electrode, and its root is fixed and directly grounded through a sealing sleeve. Directly below the electrode tips, a gas distribution nozzle sprays a high-speed gas flow into the discharge gap to sweep away and elongate the generated arc, forming an arc-shaped plasma active zone that extends upward along the gas flow direction. This greatly increases the specific surface area and contact time between the active particles and the wastewater. The fixed-bed catalytic chamber is filled with a supported metal oxide catalyst (such as MnO2 / Al2O3) for catalytic decomposition of residual O. 3， (and H2O2); The gas-liquid mixture is activated in the arc-shaped plasma active zone, enters the gas diffusion-gas-liquid distribution plate, transforms into a uniform upward flow, penetrates the entire fixed-bed catalytic chamber for deep reaction, and after treatment, the gas is discharged from the top and the liquid overflows from the water outlet on the upper side of the catalytic bed. The three-stage reaction unit employs a sliding arc discharge (GAD) structure and is optionally coupled with a catalytic bed. It is configured to be supplied with switchable gases, including at least air, oxygen, inert gases, ozone-oxygen mixtures, and ozone-containing tail gas from the secondary reaction unit. The main purpose is to generate high-temperature active particles or ultraviolet radiation to refine and protect residual stubborn pollutants. The main target pollutants are the most stubborn short-chain carboxylic acids (such as oxalic acid) and residual biological inhibitory oxidants (O3, H2O2). The outputs after the reaction are water (oxidant residue) that can be directly entered into biological treatment and tail gas that meets emission standards.

[0023] Employing a multi-stage plasma discharge synergistic oxidation treatment mechanism, this process utilizes a three-stage gradient oxidation process that generates various active substances, including hydroxyl radicals, high-energy electrons, ozone, ultraviolet light, and high-temperature active particles, in situ and on demand. Targeting different stages of pollutant degradation (macromolecules, small molecules, and stubborn fragments), it matches energy fields and oxidation mechanisms for "segmented attacks," forming a "production line" for targeted pollutant degradation. This process progressively degrades pollutants, achieving a "segmented, targeted, and relay-style" attack on different types of pollutants with different chemical bond energies. It effectively eliminates potential "blind spots" in single oxidation pathways, significantly improving the thoroughness of pollutant degradation and mineralization rate.

[0024] Example 2: Please refer to Figures 1-4 The intelligent collaborative control center is equipped with a water quality data acquisition module, a reaction status monitoring module, and a process decision-making module. The water quality data acquisition module is used to collect water quality data from the entire pretreatment system, including raw wastewater data and effluent data after treatment by each stage of the reaction unit. The water quality data acquisition module is configured as follows: at the system's main inlet, at least a first online spectrometer and a first chemical oxygen demand (COD) sensor are installed; at the outlet of the first-stage reaction unit, at least a second online spectrometer is installed; at the outlet of the second-stage reaction unit, at least an online total organic carbon (TOC) analyzer and a pH sensor are installed; and at the outlet of the tertiary reaction unit, at least an online biotoxicity monitor and a dissolved ozone (DO3) analyzer are installed. The raw wastewater data serves as the influent data for the first-level reaction unit, and the effluent data from the previous-level reaction unit serves as the influent data for the next-level reaction unit. The reaction status monitoring module is used to acquire process status data of the discharge process and material conveying of each reaction unit, including electrical data of the discharge process and physical data of the material conveying process. The electrical process data includes the real-time output voltage, output current and instantaneous discharge power from the high voltage power supply of each reaction unit. The material process data includes the real-time gas mass flow rate and pressure leading to the gas inlet branch of each reaction unit, as well as the temperature of key points inside each reactor. The process decision module receives water quality data and process status data, and is configured to perform the following operations: Initial path decision: Based on the raw wastewater data, the pre-stored process decision engine is invoked to select a matching initial process path for each reaction unit. Target feature extraction: In the continuous reaction process, key performance indicators are extracted from water quality data to target the differentiated processing objectives of each reaction unit, and used as the removal target features of each reaction unit to form first-level, second-level and third-level target datasets; Target comparison and optimization: The target datasets at each level are compared with the pre-stored standard target data at each level of the outlet to obtain the target deviation of each reaction unit. For the target deviation that reaches the upper limit, the corresponding process control model is called. Under the premise of satisfying the initial process path constraints, combined with the process status data, the optimal set of process parameters is obtained through multi-objective optimization. Command generation and execution: Based on the process parameter set, dynamic control commands are generated. According to the dynamic control commands, the discharge parameters and reaction atmosphere of each stage of the reaction unit are independently and collaboratively controlled to achieve segmented directional oxidation and synergistic treatment. During the initial path decision-making process, the process decision engine selects the initial process path based on the combination of key parameters in the original wastewater quality data. The combination of key parameters includes at least: the intensity level of the characteristic pollutant ultraviolet absorbance (UV254), the concentration of chemical oxygen demand (COD), the value of total organic carbon (TOC), the pH value, the concentration of dissolved ozone (DO3), and the biotoxicity index. The selected initial process path should at least define the baseline values ​​for the initial discharge energy level range, gas atmosphere type, gas inlet volume, and hydraulic residence time of each reaction unit. During the target feature extraction process, the extracted primary target dataset includes the removal load of macromolecular characteristic pollutants calculated based on the UV absorbance data of characteristic pollutants in the original wastewater data and primary effluent data; the extracted secondary target dataset includes the pH value in the secondary effluent data and the TOC removal rate calculated based on the TOC data in the primary and secondary effluent data; the extracted tertiary target dataset includes biotoxicity indicators and oxidant residue indicators in the tertiary effluent data. During the target comparison and optimization process, the pre-stored export standard target data at each level includes: Primary export standard target data, including the removal load of target macromolecular characteristic pollutants; Secondary export standard target data, including target TOC removal rate and target pH range; Level 3 export standard target data, including target biotoxicity thresholds and target oxidant residue limits; The target datasets at each level are compared with the pre-stored export standard target data at each level to obtain the target deviation. The target deviation is then compared with the corresponding target deviation threshold. For the target deviation that reaches the upper limit, the process control model of the corresponding reaction unit is invoked. The process control model invoked is an independent multi-objective optimization control model corresponding to each stage of the reaction unit; The optimization and control model of the first-stage reaction unit aims to minimize energy consumption and maximize the removal load of macromolecular characteristic pollutants, with discharge stability and target B / C ratio as constraints. The output adjustment parameters include, but are not limited to: the frequency and duty cycle of the high-voltage power supply, and the oxygen concentration and flow rate of the oxygen-enriched air. The optimization model of the secondary reaction unit aims to maximize the TOC removal rate and minimize the reaction temperature rise, with the target pH range and the equipment temperature limit as constraints. Its output adjustment parameters include, but are not limited to: the peak voltage and repetition frequency of the pulse corona discharge, and the pure oxygen supply rate. The optimization model of the three-stage reaction unit aims to minimize biotoxicity and oxidant residue, and is constrained by ensuring that the pH value of the effluent is within the suitable range for subsequent biological treatment. Its output adjustment parameters include, but are not limited to: the switching command for the type of gas introduced and the input power of the sliding arc discharge.

[0025] The switching logic for the gas type switching command in the tertiary reaction unit is configured as follows: When the dissolved ozone concentration in the influent or effluent of the tertiary reaction unit exceeds the first threshold that inhibits subsequent biological treatment, the control switches to introducing inert gas. When the biotoxicity index of the effluent from the tertiary reaction unit exceeds the safety limit and the dissolved ozone concentration is lower than the first threshold, the control switches to introducing oxygen or an ozone-oxygen mixture to initiate enhanced oxidation or catalytic oxidation.

[0026] An intelligent collaborative control center is added to integrate real-time monitoring of multi-source data on water quality and process status. Through the process decision module, multi-objective optimization is performed to dynamically and collaboratively regulate the discharge parameters and reaction atmosphere at each stage.

[0027] The article involves comparisons of various thresholds. Thresholds, preset values, preset ranges, etc., are set for result comparison and analysis to determine good or bad. The magnitude of these thresholds is determined by a combination of large-scale model analysis of sample data and human experience. They can also be appropriately adjusted based on seasonal or common-sense influencing factors.

[0028] In summary, the system includes primary, secondary, and tertiary reaction units connected in series along the wastewater flow direction, as well as an intelligent collaborative control center. The primary reaction unit adopts a dielectric barrier discharge structure, and introduces air or oxygen-enriched air to generate hydroxyl radicals and ozone, thereby achieving the disruption and chain breaking of macromolecular organic matter. The secondary reaction unit adopts an enhanced pulsed corona discharge structure and introduces pure oxygen or ozone-containing gas to generate high-density hydroxyl radicals and high-energy electrons, thereby achieving deep mineralization of the primary product, small molecule organic matter. The three-stage reaction unit adopts a sliding arc discharge structure and can be optionally coupled with a catalytic bed. The gas type can be switched, mainly to generate high-temperature active particles or ultraviolet radiation, to achieve the purification treatment of residual pollutants and adjust the biocompatibility of the effluent.

[0029] The intelligent collaborative control center acquires in real time inlet and outlet water quality data, discharge process data, and material transport status data of each unit through the water quality data acquisition module and the reaction status monitoring module. The process decision module performs collaborative analysis and multi-objective optimization to dynamically generate control commands, enabling independent and collaborative control of discharge parameters and reaction atmosphere of each unit.

[0030] This invention achieves efficient, segmented, and targeted removal of recalcitrant organic matter through multi-stage differentiated oxidation, multi-mechanism synergistic action, and intelligent optimization control. Furthermore, it dynamically optimizes operating parameters at each stage through a real-time monitoring data feedback system, achieving efficient, stable, and low-consumption synergistic treatment results and providing a stable and reliable pretreatment guarantee for subsequent biological treatment.

[0031] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto; any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and its improved concept, should be covered within the scope of protection of the present invention.

Claims

1. A pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation, characterized in that: It includes a primary reaction unit (1), a secondary reaction unit (2), a tertiary reaction unit (3) connected in series along the wastewater treatment flow direction, and an intelligent collaborative control center connected to each level of reaction unit. Each level of reaction unit is configured to perform differentiated oxidation treatment tasks. The intelligent collaborative control center is equipped with a water quality data acquisition module, a reaction status monitoring module, and a process decision-making module. The water quality data acquisition module is used to collect water quality data, including raw wastewater data and effluent data after treatment by each reaction unit. The reaction status monitoring module is used to acquire process status data of each reaction unit. The process decision module receives water quality data and process status data, and is configured to perform the following operations: Initial path decision: Based on the raw wastewater data, the pre-stored process decision engine is invoked to select the initial process path for each reaction unit; Target feature extraction: In the continuous reaction process, key performance indicators of each reaction unit at each level are extracted from water quality data to form first-level, second-level, and third-level target datasets; Target comparison and optimization: The target datasets at each level are compared with the pre-stored standard target data at each level of the outlet to obtain the target deviation of each reaction unit. For the target deviation that reaches the upper limit, the corresponding process control model is called. Under the premise of satisfying the initial process path constraints, combined with the process status data, the optimal set of process parameters is obtained through multi-objective optimization. Command generation and execution: Dynamic control commands are generated based on the process parameter set, and the discharge parameters and reaction atmosphere of each stage of the reaction unit are adjusted according to the dynamic control commands.

2. The pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation according to claim 1, characterized in that: The primary reaction unit (1) includes a vertical cylindrical reactor (11), a DBD electrode assembly (12), a grounding electrode (13), a primary water distribution device (14) for spraying wastewater into the reaction chamber in an atomized manner, and a primary gas distribution device (15) for introducing the first reaction gas into the bottom of the reaction chamber.

3. The pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation according to claim 2, characterized in that: The secondary reaction unit (2) includes a vertical tower reactor (21), an alloy barbed wire high-voltage electrode array (22), a honeycomb grounded cathode cylinder (23), a secondary gas distribution device (25) located at the bottom of the tower for introducing the second reaction gas, and a secondary water distribution device (24) located at the top of the reactor and connected to the outlet of the primary reaction unit (1).

4. The pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation according to claim 3, characterized in that: The three-stage reaction unit (3) includes a vertical combined reactor (31) and a gas-liquid distribution plate installed therein. The gas-liquid distribution plate divides the vertical combined reactor (31) into a sliding arc reaction chamber and a fixed bed catalytic chamber. A pair of blade electrodes (32) arranged in a V-shape are provided in the sliding arc reaction chamber. A three-stage gas distribution nozzle (33) for injecting high-speed gas flow into the electrode gap is provided below the pair of blade electrodes. The three-stage gas distribution nozzle (33) is externally connected to a three-stage water distribution pipe (34) that connects to the outlet of the secondary reaction unit (2).

5. The pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation according to claim 1, characterized in that: The process decision engine selects the initial process path based on the combination of key parameters in the original wastewater quality data. The combination of key parameters includes at least: the intensity level of the characteristic pollutant's ultraviolet absorbance (UV254), chemical oxygen demand (COD) concentration, total organic carbon (TOC) value, pH value, dissolved ozone (DO3) concentration, and biotoxicity indicators.

6. The pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation according to claim 5, characterized in that: During the target feature extraction process, the extracted primary target dataset includes the removal load of macromolecular characteristic pollutants, the extracted secondary target dataset includes pH value and TOC removal rate, and the extracted tertiary target dataset includes biotoxicity indicators and oxidant residue indicators.

7. The pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation according to claim 6, characterized in that: The process status data includes electrical process data and material process data. The electrical process data includes the real-time output voltage, output current and instantaneous discharge power from the high-voltage power supply of each reaction unit. The material process data includes the real-time gas mass flow rate and pressure leading to the gas inlet branch of each reaction unit, as well as the temperature of key points inside each reactor.

8. The pretreatment system for recalcitrant organic wastewater based on multi-stage plasma synergistic oxidation according to claim 7, characterized in that: The process control model used in the target comparison and optimization process is an independent multi-objective optimization control model corresponding to each stage of the reaction unit; Among them, the optimization and control model of the first-stage reaction unit aims to minimize energy consumption and maximize the removal load of macromolecular characteristic pollutants, with discharge stability and target B / C ratio as constraints. The output adjustment parameters include, but are not limited to: the frequency and duty cycle of the high-voltage power supply, and the oxygen concentration and flow rate of the oxygen-enriched air. The optimization model of the secondary reaction unit aims to maximize the TOC removal rate and minimize the reaction temperature rise, with the target pH range and the equipment temperature limit as constraints. Its output adjustment parameters include, but are not limited to: the peak voltage and repetition frequency of the pulse corona discharge, and the pure oxygen supply rate. The optimization model of the three-stage reaction unit aims to minimize biotoxicity and oxidant residue, and is constrained by ensuring that the pH value of the effluent is within the suitable range for subsequent biological treatment. Its output adjustment parameters include, but are not limited to: the switching command for the type of gas introduced and the input power of the sliding arc discharge.

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