A wastewater treatment apparatus and method

Abstract

The wastewater treatment device provided by the application comprises a reactor, an anode material and a cathode material arranged in the reactor, the anode material and the cathode material are parallel to the height direction of the reactor, a reaction area is formed between the cathode material and the anode material, a water inlet and a plurality of water outlets are arranged on the reactor, the heights of the plurality of water outlets are different and the plurality of water outlets are located in the reaction area, the plurality of water outlets are connected with the water inlet through pipelines arranged on the outer side of the reactor, and an independent first switch is arranged between each water outlet and the water inlet. According to different wastewater conditions, the height-diameter ratio is reasonably arranged, and when facing complex and diversified industrial wastewater, the degradation rate and degradation effect of the reactor on organic matter can reach the best state.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a wastewater treatment apparatus and method. Background Technology

[0002] With the rapid development of industry, industrial wastewater treatment has become an indispensable part of environmental protection and sustainable development, aiming to mitigate the pollution impact of industrial activities on natural water bodies. The sources of industrial wastewater can be broadly categorized as follows: first, wastewater directly generated during processing, such as dye-containing wastewater discharged from the textile printing and dyeing industry; second, wastewater generated from equipment cleaning and site flushing; third, cooling system drainage and steam condensate; and fourth, wastewater formed due to leakage or disposal of raw materials or products used in the production process. This wastewater contains various organic pollutants, residual pharmaceuticals, high concentrations of biochemical oxygen demand (BOD) and chemical oxygen demand (COD), as well as potentially toxic components, posing a threat to the environment and human health. Industrial wastewater contains organic pollutants, posing a threat to the environment and human health. Currently, the main treatment methods for recalcitrant industrial organic wastewater, characterized by complex composition, high color, high salinity, and high content of toxic and recalcitrant substances, fall into three categories: biological methods, physicochemical methods, and chemical methods. For example, chemical precipitation involves adding chemical reagents to the wastewater, causing them to react with substances in the wastewater to form water-insoluble precipitates. However, this method requires large quantities of reagents, generates significant amounts of sludge, and is therefore costly. Ozone catalytic oxidation utilizes ozone to generate hydroxyl radicals (·OH) in the system to degrade organic pollutants. It combines the strong oxidizing properties of ozone with the adsorption and catalytic characteristics of a catalyst. It does not require excessive adjustment of the wastewater's pH before the reaction, and the ·OH generated during the reaction can non-selectively degrade organic matter. However, ozone can easily escape during the reaction, posing a threat to human health, and the selection of highly efficient catalysts also leads to high costs.

[0003] Therefore, traditional wastewater treatment technologies, biological treatment, and chemical treatment are effective in some aspects, but when faced with complex and diverse industrial wastewater, existing solutions have the disadvantages of low treatment efficiency and high cost. Summary of the Invention

[0004] This invention provides a wastewater treatment device and method to solve the problem of how to efficiently treat organic waste in industrial wastewater.

[0005] The present invention provides a wastewater treatment device, comprising: a reactor, wherein an anode material and a cathode material are disposed within the reactor, and both the anode material and the cathode material are used for connection to a power source;

[0006] Both the anode and cathode materials are parallel to the height direction of the reactor, and a reaction zone is formed between the cathode and anode materials. The reactor is provided with an inlet and multiple outlets. The multiple outlets are set at different heights and are located within the reaction zone to adjust the liquid level of wastewater in the reactor.

[0007] Multiple outlets are connected to the inlet via pipes located outside the reactor to enable the wastewater to circulate within the reactor. Each outlet and inlet is equipped with an independent first switch.

[0008] The outlet is used to discharge wastewater from the reactor, and the inlet is used to input wastewater to be treated or wastewater from the outlet.

[0009] Furthermore, a particle electrode material is disposed between the anode material and the cathode material, the particle electrode material being used to suspend between the anode material and the cathode material when wastewater is introduced into the reactor.

[0010] Furthermore, it also includes a concentration sensor, a second switch, a third switch, and a transition container;

[0011] The first end of the second switch and the first end of the third switch are connected to the first switches of each of the outlets, the second end of the second switch is connected to the inlet of the reactor, the second end of the third switch is connected to the inlet of the transition container, and the outlet of the transition container is connected to the inlet of the reactor.

[0012] The concentration sensor is used to detect the concentration of organic matter in the wastewater inside the reactor;

[0013] The second switch is used to connect the outlet and inlet of the reactor, and disconnects when the organic matter concentration drops to a preset value;

[0014] The third switch is used to connect the transition container and the reactor when the organic matter concentration drops to a preset value, so that some of the wastewater in the reactor flows into the transition container, thereby lowering the wastewater level in the reactor.

[0015] Furthermore, the transition container is connected to a height adjuster, which is used to change the height of the transition container as the outlet is switched, so that the liquid level in the transition container is level with the liquid level in the reactor.

[0016] Furthermore, it also includes an aeration device, which is connected to the bottom of the reactor and is used to input gas into the reactor to generate rising bubbles in the wastewater.

[0017] Furthermore, the bottom of the reactor is conical in shape, which allows the particle electrode material falling into the bottom of the reactor to slide down the inclined surface of the cone to the air outlet of the aeration device for fluidization, thus preventing the particle electrode material from accumulating at the bottom of the reactor.

[0018] Furthermore, the anode material adopts a rod-shaped structure and is disposed in the center of the reactor, while the cathode material adopts a mesh structure and is disposed around the outside of the anode material and close to the inner wall of the reactor.

[0019] A wastewater treatment method based on a wastewater treatment device includes:

[0020] S01. Before degradation, the height-to-diameter ratio is set according to the concentration of organic matter in the wastewater, and the liquid level of the wastewater circulation in the reactor is adjusted.

[0021] S02. During the degradation process, monitor the changes in the concentration of organic matter in the wastewater. When the concentration of organic matter in the wastewater decreases, reduce the height-to-diameter ratio by lowering the liquid level of the wastewater circulation in the reactor, based on the decrease in organic matter concentration.

[0022] Furthermore, step S02 also includes: when the concentration of organic matter in the wastewater decreases, first reduce the aeration flow rate in the reactor, and then reduce the liquid level of the wastewater circulation in the reactor.

[0023] Furthermore, after performing step S02, step S03 is also included: reducing the current density of the cathode material and the anode material.

[0024] As can be seen from the above technical solutions, the present invention has the following advantages:

[0025] This solution implements a wastewater treatment device that generates strong oxidizing substances through electrocatalytic reactions, effectively degrading organic pollutants. This device requires no additional reagents, avoiding secondary pollution and significantly reducing the difficulty and cost of wastewater treatment. Furthermore, by switching between outlets of different heights, the wastewater circulation level within the reactor can be flexibly adjusted. The height-to-diameter ratio can be rationally set according to different wastewater conditions, allowing the reactor to achieve optimal degradation rates and effects for complex and diverse industrial wastewater, thereby improving the treatment efficiency of the reactor. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the overall structure of a wastewater treatment device provided in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the reactor structure in a wastewater treatment device provided in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the anode material structure in a wastewater treatment device provided in an embodiment of the present invention;

[0030] Figure 4 A comparison chart showing the degradation efficiency of ATZ under different operating modes;

[0031] Figure 5 A comparison chart showing the degradation efficiency of notebook computers under different operating modes;

[0032] Figure 6 A comparison chart showing the degradation efficiency of ATZ by different aspect ratios;

[0033] Figure 7 This is a comparison chart showing the degradation efficiency of NB with different aspect ratios.

[0034] Explanation of reference numerals in the attached drawings: 1. Reactor; 2. Anode material; 3. Cathode material; 4. Inlet; 5. Outlet; 51. First outlet; 52. Second outlet; 53. Third outlet; 54. Fourth outlet; 6. First switch; 7. Second switch; 8. Third switch; 9. Transition container; 10. Water quality sensor; 11. Aeration equipment; 12. Peristaltic pump. Detailed Implementation

[0035] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0036] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the present application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0037] Please see Figure 1-3 This invention provides a wastewater treatment device.

[0038] A wastewater treatment device includes: a reactor 1, wherein an anode material 2 and a cathode material 3 are disposed inside the reactor 1, and both the anode material 2 and the cathode material 3 are used to be connected to a power source;

[0039] Both the anode material 2 and the cathode material 3 are parallel to the height direction of the reactor 1. A reaction zone is formed between the cathode material 3 and the anode material 2. The reactor 1 is equipped with an inlet 4 and multiple outlets 5. The multiple outlets 5 are set at different heights and are located within the reaction zone to adjust the liquid level of the wastewater in the reactor 1.

[0040] Multiple outlets 5 are connected to inlet 4 through pipes located outside reactor 1 to realize the circulation of wastewater within reactor 1. Each outlet 5 and inlet 4 is equipped with an independent first switch 6.

[0041] The outlet 5 is used to discharge wastewater from reactor 1, and the inlet 4 is used to input wastewater to be treated or wastewater from outlet 5.

[0042] Understandably, in practical implementation, on the one hand, when electricity is applied to the cathode material 3 and the anode material 2, an oxidation reaction occurs on the anode surface. The anode material 2 typically has a high oxidation potential, capable of oxidizing water molecules to generate hydroxyl radicals (·OH). Simultaneously, O2 in the water is utilized to generate H2O2 through electrolysis. H2O2 further catalyzes oxidation to generate hydroxyl radicals (·OH). Hydroxyl radicals (·OH) have extremely high oxidizing power, reacting with organic matter in the wastewater to achieve degradation. This electrochemical oxidation method effectively removes pollutants and reduces secondary pollution caused by byproducts during degradation. On the other hand, different batches of industrial wastewater and varying concentrations of organic matter to be degraded result in different degradation difficulties, requiring adjustment of the aspect ratio to ensure degradation efficiency. When the organic matter concentration is the same, within a certain range, a larger aspect ratio leads to better degradation. A larger aspect ratio may create a more elongated flow channel, facilitating axial diffusion of substances, reducing boundary layer thickness, increasing the rate at which organic matter in the wastewater reaches the electrode surface, and thus accelerating the reaction. If the aspect ratio is too large, the distance that organic matter needs to diffuse vertically from the solution to the electrode surface increases, the mass transfer rate decreases, leading to concentration polarization. The distribution density of organic matter on the electrode varies greatly, and electrode areas with less organic matter distribution are more likely to trigger side reactions such as oxygen evolution under the action of current, resulting in wasted electrical energy, reduced current efficiency, and potentially accelerated anodic corrosion.

[0043] Therefore, this solution implements a wastewater treatment device that generates strong oxidizing substances through electrocatalytic reactions, effectively degrading organic pollutants. This device requires no additional reagents, avoiding secondary pollution and significantly reducing the difficulty and cost of wastewater treatment. Furthermore, by switching the outlets 5 at different heights, the wastewater circulation level in reactor 1 can be flexibly adjusted. The height-to-diameter ratio can be rationally set according to different wastewater conditions. When dealing with complex and diverse industrial wastewater, this allows reactor 1 to achieve the optimal degradation rate and effect on organic matter, thereby improving the wastewater treatment efficiency of the reaction device.

[0044] It should be noted that the height-to-diameter ratio is the ratio of the liquid level height of the wastewater circulation in reactor 1 to the diameter of reactor 1.

[0045] In a more specific embodiment, a particle electrode material is disposed between the anode material 2 and the cathode material 3, the particle electrode material being used to suspend between the anode material 2 and the cathode material 3 when wastewater is introduced into the reactor 1.

[0046] Understandably, in specific implementation, this embodiment uses a three-dimensional electrocatalytic oxidation method to degrade recalcitrant organic compounds in industrial wastewater, such as atrazine and nitrobenzene. The three-dimensional electrocatalytic oxidation method utilizes the cathode material 3, anode material 2, and particle electrode material to generate strong oxidizing substances (such as hydroxyl radicals) during electrolysis, thereby degrading the organic matter in the wastewater. Unlike traditional two-dimensional electrodes, the three-dimensional electrode adds a particle electrode, providing a larger reaction surface area and more active sites, thus resulting in higher mass transfer efficiency and reaction rate. The three-dimensional electrode system of the three-dimensional electrocatalytic oxidation is based on a two-dimensional electrode system, with granular or fragmented materials (such as activated carbon) filled between two parallel electrodes (cathode and anode). After energization, the filling material is charged under the electric field between the cathode and anode, forming many tiny electrochemical systems on the surface and undergoing electrochemical reactions, forming a new electrode in the three-dimensional electrode, called the particle electrode. The introduction of the particle electrode generates many micro-anodes within reactor 1, thereby greatly increasing the generation rate of hydroxyl radicals (·OH). Compared with the two-dimensional electrode system, the three-dimensional electrode system has a larger effective reaction area and a significantly improved current utilization rate.

[0047] It should be noted that in the three-dimensional electrocatalytic oxidation reaction, the particle electrodes are suspended inside reactor 1, increasing the electrode surface area and promoting electron transfer and oxidation. At this point, the fluid dynamics of reactor 1 are crucial for mass transfer. If the height-to-diameter ratio of reactor 1 is inappropriate, it may lead to uneven fluid distribution and uneven particle electrode distribution, affecting the reaction effect. For example, in a taller reactor 1 (larger height-to-diameter ratio), the liquid residence time may be longer, which is beneficial for the complete degradation of organic matter, but it may also increase mass transfer resistance because the organic matter in the wastewater needs more time to diffuse to the electrode surface. Conversely, in a shorter reactor 1 (smaller height-to-diameter ratio), the flow rate may increase, promoting mass transfer, but it may reduce the reaction time, leading to incomplete treatment. Therefore, in this embodiment, the circulating liquid level inside reactor 1 is adjustable by setting outlets 5 at different heights. When the concentration of organic matter in the wastewater is high, the high liquid level increases the volume of wastewater in reactor 1, providing more reaction space for organic matter. This means that under the same circulation flow rate, the residence time of wastewater in reactor 1 is prolonged. For the particle electrode, organic matter has more time to fully contact the active sites on the particle electrode surface, thereby increasing the adsorption amount of organic matter on the particle electrode surface and increasing the chance of electrocatalytic reaction between organic matter and active sites, which is beneficial to improving the degradation rate of organic matter. When the concentration of organic matter in the wastewater is low, the circulation speed of wastewater is relatively fast at low liquid levels, and the movement speed of the particle electrode in the wastewater also increases accordingly. This increases the collision frequency between the particle electrode and organic matter, which is beneficial to the rapid adsorption of low-concentration organic matter in the wastewater onto the particle electrode surface, thereby improving the reaction rate.

[0048] In a more specific embodiment, it also includes a concentration sensor, a second switch 7, a third switch 8, and a transition container 9;

[0049] The first end of the second switch 7 and the first end of the third switch 8 are connected to the first switch 6 of each outlet 5. The second end of the second switch 7 is connected to the inlet 4 of the reactor 1. The second end of the third switch 8 is connected to the inlet of the transition container 9. The outlet of the transition container 9 is connected to the inlet 4 of the reactor 1.

[0050] The concentration sensor is used to detect the concentration of organic matter in the wastewater in reactor 1;

[0051] The second switch 7 is used to connect the outlet 5 and inlet 4 of reactor 1. When the organic matter concentration drops to a preset value, the connection is disconnected.

[0052] The third switch 8 is used to connect the transition container 9 and the reactor 1 when the organic matter concentration drops to a preset value, so that some of the wastewater in the reactor 1 flows into the transition container 9, thereby lowering the wastewater level in the reactor 1.

[0053] Understandably, in specific implementation, during the reaction process, some organic matter in the wastewater is degraded, leading to a decrease in the concentration of organic matter in the wastewater. To ensure the degradation efficiency of the remaining organic matter in reactor 1 and to save energy consumption in reactor 1, this embodiment closes the second switch 7, opens the third switch 8, and changes the liquid level of the wastewater circulation in reactor 1 by switching the outlet 5 according to the concentration of organic matter in the wastewater. Therefore, this embodiment can dynamically adjust the liquid level of the wastewater circulation according to the decrease in the concentration of organic matter in the wastewater during the reaction process, and has the following advantages:

[0054] Regarding the organic matter degradation efficiency, a high degradation efficiency is maintained throughout the reaction process: In the initial stage of the reaction, the organic matter concentration in the wastewater is high, requiring a larger reaction space and a longer residence time to achieve efficient degradation. Raising the liquid level at this stage increases the contact area between the wastewater and the particle electrode, as well as the reaction time, fully utilizing the volume of reactor 1 and improving the organic matter removal rate. As the reaction progresses, the organic matter concentration gradually decreases. If the height-to-diameter ratio remains constant, side reactions are likely to occur, affecting the organic matter degradation efficiency and wasting electrical energy. Lowering the liquid level accelerates the circulation of wastewater within reactor 1, increases the current density on the particle electrode surface and the collision frequency between wastewater and the particle electrode, enhances the mass transfer process, and further promotes the degradation of residual organic matter. In terms of resource utilization, the electrode's operating parameters, such as current intensity, can be adjusted as needed at different liquid levels to match energy consumption with the organic matter degradation requirements, avoiding energy waste and achieving optimal resource allocation. Regarding cost, reasonable liquid level adjustment improves wastewater treatment efficiency and reduces the residence time of wastewater in reactor 1, thereby reducing equipment operating time and saving energy. Simultaneously, dynamic liquid level adjustment makes the particle electrode more efficient, reducing wear caused by excessively high or low organic matter concentrations, extending the particle electrode's lifespan, reducing replacement costs, and ultimately lowering overall operating costs.

[0055] In a more specific embodiment, the first switch 6, the second switch 7, and the third switch 8 are all electric switches. The first switch 6, the second switch 7, the third switch 8, and the concentration sensor are all connected to the controller. The concentration sensor detects the concentration of organic matter in the wastewater in real time and transmits the organic matter concentration data to the controller. The controller adjusts the on or off state of the first switch 6, the second switch 7, and the third switch 8 according to the concentration of organic matter in the wastewater, thereby adjusting the liquid level in the reactor 1 to obtain a reasonable height-to-diameter ratio and improve the reaction efficiency.

[0056] In a more specific embodiment, a peristaltic pump 12 is included. The second end of the second switch 7 and the outlet of the transition container 9 are both connected to the inlet of the peristaltic pump 12, and the outlet of the peristaltic pump 12 is connected to the inlet 4 of the reactor 1. It is understood that, in specific implementation, the peristaltic pump 12 causes wastewater in the reactor 1 to be discharged from the outlet 5 and input from the inlet 4, achieving wastewater circulation within the reactor 1. The flow rate of the reaction system can be controlled by changing the rotational speed of the peristaltic pump 12, thereby improving mass transfer efficiency.

[0057] In a more specific embodiment, the transition container 9 is connected to a height adjuster, which is used to change the height of the transition container 9 as the outlet 5 is switched, so that the liquid level in the transition container 9 is level with the liquid level in the reactor 1.

[0058] Understandably, during implementation, a significant difference in liquid levels between reactor 1 and transition container 9 may lead to siphoning or impaired wastewater backflow. When the liquid level in reactor 1 is too high, wastewater may be siphoned into transition container 9 before it has fully reacted, affecting the reaction efficiency. Conversely, when the liquid level in transition container 9 is too high, it may obstruct the normal outflow of wastewater from reactor 1, or even cause wastewater to flow back into reactor 1, interfering with the reaction process. Maintaining a level liquid level effectively avoids these problems, ensuring that wastewater flows normally between reactor 1 and transition container 9 according to the designed flow, enabling the entire treatment system to operate stably and efficiently.

[0059] In a more specific embodiment, the wastewater level in reactor 1 is greater than the bottom diameter of reactor 1. It can be understood that, compared to the cylindrical shape of the traditional electrocatalytic fluidized bed reactor 1, the "slender and tall" reactor 1 of the present invention has a larger height-to-diameter ratio. By increasing the height-to-diameter ratio, the residence time of oxygen in reactor 1 is increased, thereby further improving the current efficiency and degradation rate.

[0060] In a more specific embodiment, the inlet 4 is located on one side of the reactor 1, and the outlet 5 is located on the other side of the reactor 1. It is understood that, in practical implementation, by placing the inlet 4 and outlet 5 on opposite sides of the reactor 1, this embodiment allows the wastewater to form a more uniform flow within the reactor 1. From the inlet 4 to the outlet 5, the wastewater can flow relatively evenly throughout the entire space of the reactor 1, including the area where the particle electrode is located. This helps ensure sufficient contact between the particle electrode and the wastewater, avoiding localized dead zones in the water flow, and allowing the electrocatalytic reaction to proceed more uniformly throughout the reactor 1, thereby improving the uniformity and overall efficiency of organic matter degradation.

[0061] In a more specific embodiment, multiple outlets 5 are all higher than inlet 4. It is understood that after the wastewater enters reactor 1 from the lower inlet 4, it gradually rises within reactor 1, making full contact with the particle electrodes and electric field to carry out the electrocatalytic reaction. Because the outlets 5 are higher than inlet 4, the wastewater has sufficient residence time within reactor 1, allowing it to participate more fully in the reaction and improving the degradation rate of organic matter.

[0062] In a more specific embodiment, the bottom of reactor 1 is connected to an aeration device 11, which is used to input gas into reactor 1 to generate rising bubbles in wastewater.

[0063] In a more specific embodiment, the aeration device 11 is an oxygen generator.

[0064] Understandably, in practice, oxygen is supplied to reactor 1 via an oxygen generator to increase aeration during the reaction. On one hand, oxygen is a strong oxidant; in the three-dimensional electrocatalytic reaction, it can synergistically interact with the particle electrode and electric field to generate highly oxidizing reactive oxygen species, such as hydroxyl radicals (·OH). These reactive oxygen species can oxidize and decompose organic matter into harmless substances such as carbon dioxide and water, thereby improving the degradation efficiency of organic matter. On the other hand, introducing oxygen from the bottom generates bubbles. These bubbles, as they rise, cause disturbance to the liquid, enhancing convection and mixing within reactor 1, thus improving mass transfer and promoting the mass transfer of organic matter from the bulk liquid phase to the particle electrode surface. This allows more organic matter to contact the electrode and react, increasing reaction efficiency. Furthermore, it helps to remove reaction products from the electrode surface in a timely manner, preventing product accumulation on the electrode surface and inhibiting the reaction.

[0065] In a more specific embodiment, the bottom of the reactor 1 is conical in shape, which allows the particle electrode material falling into the bottom of the reactor 1 to slide down the inclined surface of the cone to the outlet of the aeration device 11 for fluidization, thus preventing the particle electrode material from accumulating at the bottom of the reactor 1.

[0066] Understandably, in specific implementation, a conical region is designed at the bottom of reactor 1. Compared with the traditional cylindrical reactor 1, this allows the particle electrodes flowing to the bottom corner to slide down to the air inlet and continue fluidization, preventing the particle electrodes from accumulating in the bottom corner and forming a "dead zone," which would lead to adverse factors such as short circuits and reduced current efficiency.

[0067] In a more specific embodiment, the concentration sensor passes through each outlet 5 in sequence. The concentration sensor is used to monitor the COD in the wastewater, by measuring the concentration of COD or organic matter in the wastewater.

[0068] It should be noted that the concentration of organic matter directly affects the kinetic requirements, mass transfer efficiency, and equipment operating conditions of the treatment process. COD (Chemical Oxygen Demand) is an important indicator for measuring the degree of pollution of organic matter and some inorganic matter in water. It represents the amount of oxidant consumed by substances in water that can be oxidized by strong oxidants (such as potassium dichromate or potassium permanganate) under certain conditions. The unit is milligrams per liter (mg / L). COD can reflect the concentration of organic matter in wastewater.

[0069] Understandably, in practical implementation, when the wastewater level in reactor 1 is at different heights, the COD in the water can still be monitored in real time, reflecting the concentration of organic matter in the wastewater. In actual water treatment processes, when the concentration sensor detects a decrease in COD, the optimal mass transfer efficiency is achieved by changing the height-to-diameter ratio. Before reducing the liquid level in reactor 1, reducing the aeration flow rate can prevent excessive aeration flow rate from pushing the particle electrodes above the reaction liquid level during the reduction of reactor 1's internal volume, thus avoiding waste of the particle electrodes. After reducing the liquid level in reactor 1, the current density is further reduced to prevent excessive current from causing side reactions of organic matter and reducing current efficiency. Therefore, this embodiment achieves better degradation efficiency by adjusting the height-to-diameter ratio, aeration flow rate, and current density, significantly reducing operating costs from an economic perspective. Compared to traditional three-dimensional electrochemical fluidized bed reactors 1 based on mechanical stirring and aeration only, this device not only has higher current efficiency but also allows mass transfer and oxidation efficiencies to mutually promote each other, resulting in a significant improvement in time and space conversion efficiency.

[0070] In a more specific embodiment, a pH sensor is also provided in reactor 1 to detect the pH value of the wastewater in reactor 1.

[0071] pH significantly affects the formation and stability of some active substances generated during electrocatalysis. Hydroxyl radicals (·OH) are crucial active substances in the electrocatalytic degradation of organic matter, and their formation is closely related to the concentrations of hydrogen and hydroxide ions in the solution. Within an appropriate pH range, the formation and stable existence of hydroxyl radicals are favorable, thereby enhancing the oxidative degradation capacity of organic matter. When the pH is too high or too low, the formation of hydroxyl radicals may be inhibited, or they may undergo side reactions with other substances, reducing their degradation effect on organic matter. Therefore, in this example, the pH of the wastewater is monitored, and when the pH is too high or too low, chemicals are added to adjust the pH, maintaining the wastewater in reactor 1 within a reasonable range.

[0072] In a more specific embodiment, the reactor 1 is equipped with a water quality sensor 10, which is used to measure the COD and pH values ​​of the wastewater in the reactor 1. Its length covers the distribution area of ​​the outlets 5 at different heights, thereby ensuring that the water quality sensor 10 can effectively monitor the wastewater regardless of how the wastewater circulation level in the reactor 1 changes.

[0073] In a more specific embodiment, the anode material 2 is a graphite rod disposed in the center of the reactor 1, and the cathode material 3 is a stainless steel mesh surrounding the inner wall of the reactor 1.

[0074] Understandably, in practical implementation, this significantly improves current efficiency and reaction efficiency compared to the traditional reactor 1 with two parallel electrode plates as anode and cathode. The rod-shaped anode is located in the center, with the electric field radiating outwards from the center. Combined with the surrounding mesh cathode, this makes the electric field distribution within reactor 1 more uniform, reducing gradient changes in electric field intensity. In contrast, the electric field between parallel anode and cathode plates is mainly concentrated in the area where the two plates face each other, with weakened electric field intensity at the edges, resulting in a significant edge effect and uneven wastewater treatment. When adjusting the liquid level, the rod-shaped anode and mesh cathode structure better promotes the mixing of wastewater within reactor 1. During the aeration process, the rising bubbles create a more complex flow field due to the structure of the rod-shaped anode and mesh cathode, enhancing the turbulence of the wastewater and allowing for better mixing of wastewater at different locations and concentrations. This helps to quickly achieve homogenization of wastewater composition and properties throughout reactor 1 when the liquid level changes, improving the efficiency of organic matter degradation. In contrast, parallel anode and cathode plates have a relatively weaker mixing effect on liquids, and may require a longer time to achieve a similar mixing effect during liquid level adjustment.

[0075] It should be noted that the construction method of reactor 1 is as follows:

[0076] A stainless steel ring mesh is placed in a glass reaction apparatus. A graphite rod anode is fixed to the top center of reactor 1 using foam and insulating rubber bands. The positive terminal of the power supply is connected to the copper rod at the top of the graphite rod electrode, and the negative terminal is connected to the top of the stainless steel mesh. By adjusting the voltage and current, the electrocatalytic reaction rate is changed, thereby generating more ·OH and increasing the degradation rate.

[0077] In a more specific embodiment, the particle electrode material is prepared using biochar.

[0078] Understandably, in practice, biochar is a product obtained from the low-temperature pyrolysis of biomass. Because the organic matter in the biomass is not fully carbonized, some functional groups are retained, such as carboxyl, ketone, phenolic, quinone, and hydroquinone groups. These retained groups on biochar possess redox properties, enabling the functionalization of the biochar. The active sites on biochar can promote the generation of strong oxidizing free radicals in electrocatalytic oxidation systems, and biochar particle electrodes are inexpensive and easy to prepare.

[0079] The preparation method of the particle electrode in this embodiment is as follows:

[0080] S11. Preparation of biochar-supported copper (BC-Cu(II)) particle electrodes: The biomaterial (tea leaves) is rinsed to remove impurities adhering to the surface, and then dried in an oven until the surface is dry and free of moisture. The washed tea leaves are then ground into powder in a grinder, removed, bagged, sealed, and kept dry.

[0081] S12. Pour the crushed bio-material (tea powder) into a crucible, gently shake it to keep the surface of the material flat, and place it in a muffle furnace for carbonization (while simultaneously introducing CO2 into the muffle furnace). Set the muffle furnace operating parameters to calcination temperatures of 400℃, 500℃, and 600℃, and calcination time of 2 hours. After calcination, a total of 3 types of BC (the raw material has 3 different temperatures) are obtained. Grind each type of BC into powder and pass it through a 200-mesh sieve to complete the preparation of BC (powdered tea biochar).

[0082] S13. Add 1g BC and 0.5g CuCl2 to 40ml of ultrapure water and stir at room temperature for 24h to allow copper ions to adsorb onto the biochar. After standing for 12h, adjust the pH to neutral and then place it in an oven to dry. After drying, calcine it in a muffle furnace (while simultaneously introducing CO2 into the muffle furnace). Set the muffle furnace operating parameters to a calcination temperature of 400℃. After calcination, grind the biochar particles and pass them through a 200-mesh sieve to complete the preparation of copper-modified tea biochar particle electrodes.

[0083] This invention also provides a degradation method, comprising the following steps:

[0084] S01. Before degradation, the height-to-diameter ratio is set according to the concentration of organic matter in the wastewater, the liquid level of the wastewater circulation in the reactor 1 is adjusted, one of the multiple outlets 5 is opened, and the other outlets 5 are closed.

[0085] When COD ≥ the first preset value, control the first water outlet 51 to open and the other water outlets 5 to close.

[0086] When the second preset value ≤ COD < the first preset value, control the second water outlet 52 to open and the other water outlets 5 to close.

[0087] When the third preset value ≤ COD < the second preset value, control the third water outlet 53 to open and the other water outlets 5 to close.

[0088] When COD is less than the third preset value, the fourth outlet 54 is opened and the other outlets 5 are closed.

[0089] Among them, the height of the first water outlet 51 is greater than the height of the second water outlet 52; the height of the second water outlet 52 is greater than the height of the second water outlet 52; the first preset value is greater than the second preset value and the third preset value.

[0090] In this embodiment, the diameter of the device is constant. The height of the reaction volume is adjusted by regulating the outlets 5 at different heights, thereby achieving different height-to-diameter ratios. This embodiment adjusts the water level in the reaction vessel according to the concentration of organic matter in the wastewater, and rationally sets the height-to-diameter ratio based on different wastewater conditions. When dealing with complex and diverse industrial wastewater, this helps the reactor 1 achieve the optimal degradation rate and effect of organic matter, thereby improving the wastewater treatment efficiency of the reaction device.

[0091] S02. During the degradation process, monitor the changes in the concentration of organic matter in the wastewater. When the concentration of organic matter in the wastewater decreases, reduce the height-to-diameter ratio by lowering the liquid level of the wastewater circulation in reactor 1, based on the decrease in organic matter concentration.

[0092] During the reaction, the concentration of organic matter in the wastewater is monitored in real time. When the concentration of organic matter decreases, i.e., the COD concentration decreases, side reactions are likely to occur if the height-to-diameter ratio remains unchanged, affecting the degradation efficiency of organic matter and wasting electrical energy. In this embodiment, lowering the liquid level can accelerate the circulation speed of wastewater in reactor 1, increase the current density on the particle electrode surface and the collision frequency between wastewater and the particle electrode, enhance the mass transfer process, and further promote the degradation of remaining organic matter. In terms of resource utilization, the working parameters of the electrode, such as current intensity, can be adjusted as needed at different liquid levels to match energy consumption with the organic matter degradation requirements, avoiding energy waste and achieving optimal resource allocation. In terms of cost, by reasonably adjusting the liquid level, the wastewater treatment efficiency is improved, and the residence time of wastewater in reactor 1 is reduced, thereby reducing equipment operating time and saving energy. At the same time, dynamic adjustment of the liquid level can make the use of the particle electrode more efficient, reduce the wear and tear on the particle electrode caused by excessively high or low organic matter concentrations, extend the service life of the particle electrode, reduce the cost of replacing the particle electrode, and thus reduce the overall operating cost.

[0093] Understandably, during the actual implementation, organic matter is decomposed in the reaction process, and the concentration of organic matter will decrease after a period of time.

[0094] In a more specific embodiment, step S02 further includes: when the COD concentration decreases, first reduce the aeration flow rate, and then lower the water level in reactor 1 to prevent the excessive aeration flow rate from pushing the particle electrode above the liquid surface during the process of reducing the internal volume of reactor 1, thus causing waste of the particle electrode.

[0095] In a more specific embodiment, step S03 is also included: reducing the current density of the cathode material 3 and the anode material 2.

[0096] Understandably, in practical implementation, on the one hand, reducing the current density can prevent excessive current from causing side reactions of organic matter and reducing current efficiency; on the other hand, reducing the current density after adjusting the wastewater level in reactor 1 is necessary because the change in the liquid level in reactor 1 during the height-to-diameter ratio adjustment process will alter the liquid distribution and flow field within reactor 1, thereby affecting the electric field distribution. A suitable liquid circulation height can make the electric field more evenly distributed in the reaction area, ensuring that the particle electrodes can fully function. Reducing the current density after optimizing the electric field distribution is crucial. If the current density is reduced without adjusting the liquid circulation height, uneven electric field distribution may lead to some areas reacting too slowly, while other areas still have excessively high current densities, affecting the overall treatment effect.

[0097] In a more specific embodiment, the effects of the above embodiments are illustrated through an electrocatalytic oxidation experiment of industrial wastewater.

[0098] The steps for constructing a wastewater treatment device in this embodiment are as follows:

[0099] S21. Preparation of biochar-supported copper (BC-Cu(II)) particle electrodes;

[0100] S22, Construction of reactor 1;

[0101] S23. Connect the peristaltic pump 12 to the reactor 1;

[0102] S24. The air inlet at the bottom of reactor 1 is connected to an oxygen generator, so that oxygen flows into the aeration from the bottom of reactor 1 during operation, thereby causing the particle electrodes to fluidize within reactor 1 during the reaction.

[0103] S25. Four outlets 5 with heights of 10cm, 20cm, 30cm and 40cm are set on the right side of reactor 1, which can handle three-dimensional electrocatalytic oxidation reactions with different volumes of reaction liquid, realizing a multi-purpose form.

[0104] S26. Insert the water quality monitor from the top opening of reactor 1 and turn on the power switch so that various water quality parameters can be monitored in real time during the reaction process. The water quality monitor includes a temperature sensor, a pH sensor and an organic matter concentration sensor.

[0105] S27. After the reaction system is connected, add the reaction liquid and the particle electrode. Turn on the peristaltic pump 12 switch and the corresponding outlet 5 and inlet 4 valves. The reaction device starts fluidized circulation. Water flows out of the device outlet 5 to the water tank, and then flows to the peristaltic pump 12. Driven by the peristaltic pump 12, it flows to the inlet 4 and back to the reactor 1. This process can realize the adsorption process of the particle electrode to remove pollutants.

[0106] S28. Based on (7), turn on the power switch, and the current flows into reactor 1 to start the electrocatalytic oxidation process, generating a large amount of ·OH to oxidize pollutants.

[0107] The experimental procedure is as follows:

[0108] Wastewater from a pharmaceutical factory was collected and filtered using a 0.45 μm aqueous membrane. High-performance liquid chromatography (HPLC) was used to detect atrazine (ATZ) and nitrobenzene (NB) in the industrial wastewater. After operating the reactor according to step S26, different operating modes and different height-to-diameter ratios were investigated (particle electrode dosage 1 g / L; current density 25 mA / cm²; gas flow rate 50 mL / min; electrolyte 0.1 M / L sodium sulfate; height-to-diameter ratio 8:1). Figure 4 and Figure 5 All four systems—two-dimensional electrocatalytic aeration, three-dimensional electrocatalytic aeration, three-dimensional electrocatalytic circulation, and simultaneous three-dimensional electrocatalytic aeration + circulation—show that aeration and circulation both improve the degradation efficiency of the system. The optimal degradation efficiency is achieved when aeration and circulation are performed simultaneously, resulting in a 78.5% degradation of ATZ and an 82.3% degradation of NB. Figure 6 , Figure 7 In this study, by conducting reactor 1 degradation on solutions of different volumes and comparing the degradation effects of different height-to-diameter ratios at different outlet heights 5, it was found that the optimal degradation effect was achieved at a ratio of 8:1 (outlet 5 at 40cm). Therefore, for the same organic matter concentration, the larger the height-to-diameter ratio, the better the effect. Thus, by setting outlets 5 at different heights, this scheme allows for adjustment of the height-to-diameter ratio before the reaction begins, based on the wastewater conditions with different organic matter concentrations, which is beneficial for achieving the best degradation efficiency.

[0109] Table 1. Water quality of raw water

[0110] ATZ concentration 10-16.6 μM / L NB concentration 15-24.1 μM / L pH 6.98-7.36 temperature 25℃

[0111] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wastewater treatment apparatus, characterized by, include: A reactor, wherein an anode material and a cathode material are disposed within the reactor, and both the anode and cathode materials are used for connection to a power source; Both the anode and cathode materials are parallel to the height direction of the reactor, and a reaction zone is formed between the cathode and anode materials. The reactor is provided with an inlet and multiple outlets. The multiple outlets are set at different heights and are located within the reaction zone to adjust the liquid level of wastewater in the reactor. Multiple outlets are connected to the inlet via pipes located outside the reactor to enable the wastewater to circulate within the reactor. Each outlet and inlet is equipped with an independent first switch. The outlet is used to discharge wastewater from the reactor, and the inlet is used to input wastewater to be treated or wastewater from the outlet. The wastewater treatment device also includes a concentration sensor, a second switch, a third switch, and a transition container; The first end of the second switch and the first end of the third switch are connected to the first switches of each of the outlets, the second end of the second switch is connected to the inlet of the reactor, the second end of the third switch is connected to the inlet of the transition container, and the outlet of the transition container is connected to the inlet of the reactor. The concentration sensor is used to detect the concentration of organic matter in the wastewater inside the reactor; The second switch is used to connect the outlet and inlet of the reactor, and disconnects when the organic matter concentration drops to a preset value; The third switch is used to connect the transition container and the reactor when the organic matter concentration drops to a preset value, so that some of the wastewater in the reactor flows into the transition container, thereby lowering the wastewater level in the reactor. The wastewater treatment device also includes a controller, and the first switch, the second switch, the third switch, and the concentration sensor are all connected to the controller. The controller is used to adjust the off or on states of the first switch, the second switch, and the third switch during the degradation process based on the decrease in organic matter concentration in the wastewater obtained from the organic matter concentration data sent by the concentration sensor. This reduces the height-to-diameter ratio of the liquid level in the wastewater circulation within the reactor. The height-to-diameter ratio is the ratio of the liquid level in the wastewater circulation within the reactor to the diameter of the reactor.

2. A wastewater treatment device according to claim 1, wherein A particle electrode material is disposed between the anode material and the cathode material, and the particle electrode material is used to suspend between the anode material and the cathode material when wastewater is introduced into the reactor.

3. A wastewater treatment apparatus according to claim 1 or 2, characterised in that, The transition container is connected to a height adjuster, which is used to change the height of the transition container as the outlet switches, so that the liquid level in the transition container is level with the liquid level in the reactor.

4. A wastewater treatment device according to claim 1 or 2, characterised in that It also includes an aeration device, which is connected to the bottom of the reactor. The aeration device is used to input gas into the reactor to generate rising bubbles in the wastewater.

5. A wastewater treatment device according to claim 4, wherein The bottom of the reactor is conical, which allows the particle electrode material falling into the bottom of the reactor to slide down the inclined surface of the cone to the air outlet of the aeration device for fluidization, thus preventing the particle electrode material from accumulating at the bottom of the reactor.

6. A wastewater treatment device according to claim 4, wherein The anode material has a rod-shaped structure and is located in the center of the reactor. The cathode material has a mesh-like structure and is located around the outside of the anode material and close to the inner wall of the reactor.

7. A treatment method based on the wastewater treatment device according to any one of claims 1 to 6, characterized by, include: S01. Before degradation, the height-to-diameter ratio is set according to the concentration of organic matter in the wastewater, and the liquid level of the wastewater circulation in the reactor is adjusted. S02. During the degradation process, monitor the changes in the concentration of organic matter in the wastewater. When the concentration of organic matter in the wastewater decreases, reduce the height-to-diameter ratio by lowering the liquid level of the wastewater circulation in the reactor, based on the decrease in organic matter concentration.

8. A method of treatment according to claim 7, wherein, Step S02 further includes: when the concentration of organic matter in the wastewater decreases, first reduce the aeration flow rate in the reactor, and then reduce the liquid level of the wastewater circulation in the reactor.

9. A method of treatment according to claim 8, wherein, After completing step S02, step S03 is also included: reducing the current density of the cathode material and the anode material.

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