Wastewater treatment device and method

Abstract

The wastewater treatment device provided by the invention comprises a reactor, an anode material and a cathode material are arranged in the reactor, the anode material and the cathode material are both 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 formed in the reactor, the plurality of water outlets are different in height and are positioned 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 the invention, the height-diameter ratio is reasonably set according to different wastewater conditions, and the degradation rate and degradation effect of the reactor on organic matters can reach the optimal state when the reactor is used for complex and diversified industrial wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and particularly to a wastewater treatment device and method. Background Art

[0002] With the rapid development of industry, industrial wastewater treatment is an indispensable part of the fields of environmental protection and sustainable development, aiming to reduce the pollution impact of industrial activities on natural water bodies. The sources of industrial wastewater can be roughly classified into the following categories: First, the wastewater directly generated during the processing, such as the dye-containing wastewater discharged by the textile and printing industry; second, the wastewater generated from equipment cleaning and site flushing; third, the drainage of the cooling system and steam condensate; fourth, the wastewater formed due to leakage and abandonment of raw materials or products used in the production process. These wastewaters contain a variety of organic pollutants, residual drugs, high concentrations of biochemical oxygen demand and chemical oxygen demand, as well as potential toxic components, posing a threat to the environment and human health. Industrial wastewater contains organic pollutants and poses a threat to the environment and human health. In view of the characteristics of complex composition, high chromaticity, salt content, and high content of toxic and difficult-to-degrade substances, the current treatment methods for industrial refractory organic wastewater mainly include three categories: biological methods, physical and chemical methods, and chemical methods. For example, the chemical precipitation method is to add chemical reagents to the wastewater to make the chemical reagents react with the substances in the wastewater to generate precipitates that are insoluble in water. However, this method has a large consumption of chemical reagents, generates a large amount of sludge, and has the problem of too high cost; the ozone catalytic oxidation method is to use ozone to generate hydroxyl radicals (·OH) in the system to degrade organic pollutants. It combines the strong oxidizing property of ozone, the adsorption and catalytic characteristics of the catalyst. It does not require excessive adjustment of the pH of the wastewater before the reaction. The ·OH generated during the reaction can degrade organic matter without selectivity. However, ozone is likely to escape during the reaction and pose a threat to the human body, and the selection of highly efficient catalysts will also cause the problem of high cost.

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

[0004] The present invention provides a wastewater treatment device and method for solving the problem of how to efficiently treat organic wastes in industrial wastewater.

[0005] A wastewater treatment device provided by the present invention includes: a reactor, in which an anode material and a cathode material are arranged, and both the anode material and the cathode material are used for connecting to a power supply;

[0006] Both the anode material and the cathode material are parallel to the height direction of the reactor. A reaction region is formed between the cathode material and the anode material. The reactor is provided with a water inlet and a plurality of water outlets. The heights of the plurality of water outlets are set differently and are located within the reaction region, for adjusting the liquid level of the wastewater in the reactor.

[0007] The plurality of water outlets are all connected to the water inlet through pipes arranged outside the reactor, for realizing the circulating flow of the wastewater in the reactor. An independent first switch is arranged between each water outlet and the water inlet.

[0008] The water outlet is used for outputting the wastewater in the reactor, and the water inlet is used for inputting the wastewater to be treated or the wastewater from the water outlet.

[0009] Further, a particle electrode material is arranged between the anode material and the cathode material. The particle electrode material is used for suspending between the anode material and the cathode material when the wastewater is introduced into the reactor.

[0010] Further, it further 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 water outlet. The second end of the second switch is connected to the water inlet of the reactor. The second end of the third switch is connected to the inlet of the transition container. The outlet of the transition container is connected to the water inlet of the reactor.

[0012] The concentration sensor is used for detecting the organic matter concentration of the wastewater in the reactor.

[0013] The second switch is used for connecting the water outlet and the water inlet of the reactor, and disconnecting the connection when the organic matter concentration is reduced to a preset value.

[0014] The third switch is used for connecting the transition container and the reactor when the organic matter concentration is reduced to a preset value, so that part of the wastewater in the reactor flows into the transition container, thereby reducing the liquid level of the wastewater in the reactor.

[0015] Further, the transition container is connected to a height regulator. The height regulator is used for realizing that the height of the transition container changes with the switching of the water outlet, so that the liquid level in the transition container is flush with the liquid level in the reactor.

[0016] Further, it further includes an aeration device. The bottom of the reactor is connected to the aeration device. The aeration device is used for inputting gas into the reactor to generate rising bubbles in the wastewater.

[0017] Further, the bottom of the reactor is conical in shape, which is used to enable the particle electrode material falling to the bottom of the reactor to slide down along the inclined surface of the cone to the air outlet of the aeration device for fluidization, avoiding the accumulation of the particle electrode material at the bottom of the reactor.

[0018] Further, the anode material adopts a rod-like structure, the anode material is arranged in the center of the reactor, the cathode material adopts a mesh structure, and the cathode material is arranged around the outside of the anode material and close to the inner wall of the reactor.

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

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

[0021] S02. During degradation, monitor the change in the concentration of organic matter in the wastewater. When the concentration of organic matter in the wastewater decreases, reduce the height-diameter ratio by reducing the liquid level height of the wastewater circulation in the reactor according to the decrease in the concentration of organic matter.

[0022] Further, 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 height of the wastewater circulation in the reactor.

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

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

[0025] This solution implements a wastewater treatment device, which can effectively degrade organic pollutants by generating strongly oxidizing substances through an electrocatalytic reaction. This device does not require the addition of other chemicals, avoiding the generation of secondary pollution and significantly reducing the difficulty and cost of wastewater treatment. In addition, by switching the water outlets at different heights, the liquid level height of the wastewater circulation in the reactor can be flexibly adjusted, and the height-diameter ratio can be reasonably set according to different wastewater conditions. When facing complex and diverse industrial wastewater, it is beneficial to achieve the best state of the degradation rate and degradation effect of the reactor on organic matter, thereby improving the treatment efficiency of the reaction device for wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 Schematic diagram of the overall structure of a wastewater treatment device provided by an embodiment of the present invention;

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

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

[0030] Figure 4 Comparison diagram of the degradation efficiency of ATZ under different operating modes;

[0031] Figure 5 Comparison diagram of the degradation efficiency of NB under different operating modes;

[0032] Figure 6 Comparison diagram of the degradation efficiency of ATZ under different height-to-diameter ratios;

[0033] Figure 7 Comparison diagram of the degradation efficiency of NB under different height-to-diameter ratios.

[0034] Explanation of reference numerals: 1, reactor; 2, anode material; 3, cathode material; 4, water inlet; 5, water outlet; 51, first water outlet; 52, second water outlet; 53, third water outlet; 54, fourth water 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 manners

[0035] In order to make the invention objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0036] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and drawings of the present invention are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0037] Please refer to Figure 1-3 , an embodiment of the present invention provides a wastewater treatment device.

[0038] A wastewater treatment device, comprising: a reactor 1, in which an anode material 2 and a cathode material 3 are arranged, and both the anode material 2 and the cathode material 3 are used for connecting 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 area is formed between the cathode material 3 and the anode material 2, and the reactor 1 is provided with a water inlet 4 and a plurality of water outlets 5. The heights of the plurality of water outlets 5 are set differently and are located in the reaction area, and are used to adjust the liquid level height of the wastewater in the reactor 1;

[0040] The plurality of water outlets 5 are all connected to the water inlet 4 through pipes arranged outside the reactor 1 to realize the circulating flow of the wastewater in the reactor 1, and an independent first switch 6 is arranged between each water outlet 5 and the water inlet 4;

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

[0042] It can be understood that in specific implementation, on the one hand, when an electric current is applied to the cathode material 3 and the anode material 2, an oxidation reaction will occur on the anode surface. The anode material 2 usually has a relatively high oxidation potential and can oxidize water molecules to generate hydroxyl radicals (·OH). At the same time, it utilizes O2 in the water to produce H2O2 through electrolysis. H2O2 further catalytically oxidizes to generate hydroxyl radicals (·OH). Hydroxyl radicals (·OH) have extremely high oxidation ability and react with the organic matter in the wastewater to achieve the degradation purpose. By using this electrochemical oxidation method to degrade the organic matter in the wastewater, not only can pollutants be effectively removed, but also the secondary pollution caused by the generation of by-products during the degradation process can be reduced. On the other hand, for different batches of industrial wastewater, factors such as different concentrations of organic matter to be degraded in the wastewater lead to different degradation difficulties, and it is necessary to adjust the height-diameter ratio to ensure the degradation efficiency. When the concentration of organic matter is the same, within a certain range, the larger the height-diameter ratio, the better the degradation effect. A larger height-diameter ratio may make the solution form a relatively slender flow channel, which is conducive to the diffusion of substances along the axis, reduces the boundary layer thickness, and increases the rate of organic matter in the wastewater reaching the electrode surface, thus accelerating the reaction. If the height-diameter ratio is too large, the distance for the organic matter to vertically diffuse from the solution bulk to the electrode surface increases, the mass transfer rate decreases, resulting in concentration polarization. The distribution density of the organic matter on the electrodes has a large gap, and the electrode area with less organic matter distribution is prone to trigger side reactions such as oxygen evolution under the action of the current, leading to waste of electric energy, reduction of current efficiency, and possible acceleration of anode corrosion.

[0043] Therefore, this solution implements a wastewater treatment device that can effectively degrade organic pollutants by generating strongly oxidizing substances through an electrocatalytic reaction. This device does not require the addition of other chemicals, avoiding the generation of secondary pollution and significantly reducing the difficulty and cost of wastewater treatment. In addition, by switching the water outlet 5 at different heights, the height of the wastewater circulation liquid level in the reactor 1 can be flexibly adjusted, and the height-diameter ratio can be reasonably set according to different wastewater conditions. When facing complex and diverse industrial wastewater, it is beneficial for the reactor 1 to achieve the best state in terms of the degradation rate and degradation effect of organic matter, thereby improving the treatment efficiency of the reaction device for wastewater.

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

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

[0046] It can be understood that in specific implementation, this embodiment degrades refractory organic matters in industrial wastewater, such as atrazine and nitrobenzene, etc., through the three-dimensional electrocatalytic oxidation method. The three-dimensional electrocatalytic oxidation method utilizes the cathode material 3, the anode material 2, and the particle electrode material to generate strongly oxidizing substances (such as hydroxyl radicals) during the electrolysis process, thereby degrading the organic matters in the wastewater. Different from the traditional two-dimensional electrodes, the three-dimensional electrodes add particle electrodes, providing a larger reaction surface area and more active sites. Therefore, the mass transfer efficiency and reaction rate are higher. The three-dimensional electrode system of the three-dimensional electrocatalytic oxidation is based on the two-dimensional electrode system, and granular or debris-like materials (such as activated carbon) are filled between two parallel electrodes (cathode and anode). After being energized, the filled material is charged under the electric field between the cathode and the anode, and many tiny electrochemical systems can be formed on the surface and electrochemical reactions occur, forming a new electrode in the three-dimensional electrode, which is called the particle electrode. The introduction of the particle electrode makes many micro-anodes generated in the reactor 1, thus greatly enhancing the generation rate of hydroxyl radicals (·OH). Compared with the two-dimensional electrode system, the effective reaction area of the three-dimensional electrode system increases, and the current utilization rate is greatly improved.

[0047] It should be noted that in the three-dimensional electrocatalytic oxidation reaction, the particle electrodes are suspended in the reactor 1, increasing the electrode surface area and promoting electron transfer and oxidation reactions. At this time, the hydrodynamic state of the reactor 1 is crucial for mass transfer. If the aspect ratio of the reactor 1 is not appropriate, it may lead to uneven fluid distribution and uneven distribution of particle electrodes, affecting the reaction effect. For example, in a higher reactor 1 (with a larger aspect ratio), the liquid residence time may be longer, which is beneficial to the full degradation of organic matters, but at the same time, it may also lead to an increase in mass transfer resistance because the organic matters in the wastewater need a longer time to diffuse to the electrode surface; on the contrary, in a lower reactor 1 (with a smaller aspect ratio), the flow rate may increase, promoting mass transfer, but the reaction time may be reduced, resulting in incomplete treatment. Therefore, this embodiment makes the circulating liquid level in the reactor 1 adjustable by setting the water outlets 5 at different heights. When the concentration of organic matters in the wastewater is relatively high, the high liquid level increases the volume of wastewater in the reactor 1, providing a larger reaction space for organic matters. This means that at the same circulating flow rate, the residence time of the wastewater in the reactor 1 is extended. For the particle electrodes, the organic matters have more time to fully contact the active sites on the surface of the particle electrodes, thereby increasing the adsorption amount of organic matters on the surface of the particle electrodes and increasing the chance of electrocatalytic reactions occurring between the organic matters and the active sites, which is beneficial to improving the degradation rate of organic matters; when the concentration of organic matters in the wastewater is relatively low, the circulating speed of the wastewater is relatively fast at the low liquid level, and the movement speed of the particle electrodes in the wastewater also increases accordingly. This increases the collision frequency between the particle electrodes and the organic matters, which is beneficial to the rapid adsorption of low-concentration organic matters in the wastewater onto the surface of the particle electrodes, thereby increasing the reaction rate.

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

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

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

[0051] The second switch 7 is used to connect the water outlet 5 and the water inlet 4 of the reactor 1, and disconnects the connection when the organic matter concentration decreases to a preset value;

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

[0053] It can be understood that during the specific implementation, during the reaction process, some organic matter in the wastewater is degraded, resulting in a decrease in the organic matter concentration in the wastewater. To ensure the degradation efficiency of the remaining organic matter in the reactor 1 and save the energy consumption of the reactor 1, in this implementation, the second switch 7 is closed, the third switch 8 is opened, and the liquid level height of the wastewater circulation in the reactor 1 is changed by switching the water outlet 5 according to the organic matter concentration in the wastewater. Therefore, this embodiment can dynamically adjust the liquid level height of the wastewater circulation according to the decrease in the organic matter concentration of the wastewater during the reaction process, and has the following advantages:

[0054] In terms of the degradation efficiency of organic matter, a relatively high degradation efficiency of organic matter is maintained throughout the reaction process: in the initial stage of the reaction, the concentration of organic matter in the wastewater is relatively high, and a larger reaction space and longer residence time are required to achieve efficient degradation. At this time, raising the liquid level can increase the contact area and reaction time between the wastewater and the particle electrode, make full use of the volume of the reactor 1, and improve the removal rate of organic matter. As the reaction proceeds, the concentration of organic matter gradually decreases. If the height-diameter ratio remains unchanged, side reactions are likely to occur, affecting the degradation efficiency of organic matter and wasting electric energy. Lowering the liquid level can accelerate the circulation speed of the wastewater in the reactor 1, increase the current density on the surface of the particle electrode and the collision frequency between the wastewater and the particle electrode, strengthen the mass transfer process, and further promote the degradation of the remaining organic matter; in terms of resource utilization, at different liquid level heights, the working parameters of the electrode, such as the current intensity, can be adjusted according to needs, so that the energy consumption matches the demand for organic matter degradation, avoiding energy waste and achieving the optimal allocation of resources; in terms of cost, by reasonably adjusting the liquid level, the wastewater treatment efficiency is improved, the residence time of the wastewater in the reactor 1 is reduced, so that the operation time of the equipment can be shortened, energy consumption can be saved. At the same time, the dynamic adjustment of the liquid level can make the use of the particle electrode more efficient, reduce the loss of the particle electrode caused by too high or too low organic matter concentration, extend the service life of the particle electrode, reduce the cost of replacing the particle electrode, and thus reduce the overall operation cost.

[0055] In a more specific embodiment, the first switch 6, the second switch 7 and the third switch 8 all adopt 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 real-time detects the concentration of organic matter in the wastewater and transmits the organic matter concentration data to the controller. The controller adjusts the off or on 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, so as to adjust the liquid level height in the reactor 1, obtain a reasonable height-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. The outlet of the peristaltic pump 12 is connected to the water inlet 4 of the reactor 1. It can be understood that in specific implementation, the wastewater in the reactor 1 is output from the water outlet 5 of the reactor 1 and input from the water inlet 4 through the peristaltic pump 12, realizing the water circulation of the wastewater in the reactor 1. The mass transfer efficiency can be improved by changing the rotation speed of the peristaltic pump 12 to control the flow rate of the reaction system.

[0057] In a more specific embodiment, the transition container 9 is connected to a height regulator, and the height regulator is used to make the height of the transition container 9 change with the switching of the water outlet 5, so that the liquid level in the transition container 9 is flush with the liquid level in the reactor 1.

[0058] It can be understood that during specific implementation, if there is a large difference in the liquid levels of the reactor 1 and the transition container 9, siphon phenomenon may occur or the smooth flow of wastewater backflow may be affected. When the liquid level in the reactor 1 is too high, it is possible that the wastewater is siphoned to the transition container 9 through the pipeline without sufficient reaction, affecting the reaction effect; while when the liquid level in the transition container 9 is too high, it may hinder the normal outflow of wastewater in the reactor 1, and even cause the wastewater to flow back into the reactor 1, interfering with the reaction process. Keeping the liquid levels equal can effectively avoid these problems, ensure the normal flow of wastewater between the reactor 1 and the transition container 9 according to the designed process, and enable the entire treatment system to operate stably and efficiently.

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

[0060] In a more specific embodiment, the water inlet 4 is arranged on one side of the reactor 1, and the water outlet 5 is arranged on the other side of the reactor 1. It can be understood that during specific implementation, by arranging the water inlet 4 and the water outlet 5 on the opposite sides within the reactor 1 respectively in this embodiment, a relatively uniform water flow can be formed in the reactor 1. During the process from the water inlet 4 to the water outlet 5, the wastewater can flow through the entire reactor 1 space relatively evenly, including the area where the particle electrodes are located. This helps the particle electrodes to come into full contact with the wastewater, avoid the occurrence of local water flow dead corners, and enable the electrocatalytic reaction to proceed relatively evenly throughout the reactor 1, improving the uniformity and overall efficiency of organic matter degradation.

[0061] In a more specific embodiment, multiple water outlets 5 are all higher than the water inlet 4. It can be understood that after the wastewater enters the reactor 1 from the lower-position water inlet 4, it will gradually rise in the reactor 1, come into full contact with the particle electrodes and the electric field, and carry out electrocatalytic reaction. Since the water outlet 5 is higher than the water inlet 4, the wastewater has sufficient residence time in the reactor 1, can participate in the reaction more fully, and improve the degradation rate of organic matter.

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

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

[0064] It can be understood that, in specific implementation, oxygen is supplied to the reactor 1 by an oxygen generator to achieve increased aeration during the reaction. On the one hand, oxygen is a strong oxidant. In the three-dimensional electrocatalytic reaction, it can cooperate with the particle electrode and the electric field to generate reactive oxygen species with strong oxidizing properties, such as hydroxyl radicals (·OH), etc. These reactive oxygen species can oxidize and decompose organic substances into harmless substances such as carbon dioxide and water, thereby improving the degradation efficiency of organic substances. On the other hand, introducing oxygen from the bottom will generate bubbles. During the rising process of these bubbles, they will cause the disturbance of the liquid, enhance the convection and mixing of the liquid in the reactor 1, thereby improving the mass transfer effect, promoting the mass transfer of organic substances from the liquid phase main body to the surface of the particle electrode, enabling more organic substances to come into contact with the electrode and react, improving the reaction efficiency, and helping to timely remove the products generated by the reaction from the electrode surface to prevent the accumulation of products on the electrode surface and inhibit the progress of the reaction.

[0065] In a more specific embodiment, the bottom shape of the reactor 1 is conical, which is used to realize that the particle electrode material falling to the bottom of the reactor 1 slides down along the inclined surface of the cone to the air outlet of the aeration device 11 for fluidization to avoid the accumulation of the particle electrode material at the bottom of the reactor 1.

[0066] It can be understood that, in specific implementation, a conical area is designed at the bottom of the reactor 1. Compared with the traditional cylindrical reactor 1, it can make the example electrodes flowing to the bottom corners slide to the air inlet for continuous fluidization, preventing the particle electrodes from accumulating at the bottom corners to form a "dead zone", which may lead to adverse factors such as short circuit and reduction of current efficiency.

[0067] In a more specific embodiment, the concentration sensor passes through each water outlet 5 in turn. The concentration sensor is used to monitor the COD in the wastewater and determine the concentration of COD or organic substances in the wastewater.

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

[0069] It can be understood that during specific implementation, when the wastewater level in the reactor 1 is at different heights, the COD in the water can still be monitored in real time, and the concentration of organic matter in the wastewater can be reflected in real time. In the application of the actual water treatment process, when the concentration sensor monitors a decrease in the COD of the water quality, the optimal mass transfer efficiency can be achieved by changing the height-diameter ratio. Before reducing the liquid level height of the reactor 1, reducing the aeration flow rate can prevent excessive aeration flow rate from flushing the particle electrode above the liquid level height of the reaction liquid during the process of reducing the internal volume of the reactor 1, resulting in waste of the particle electrode. After reducing the liquid level height of the reactor 1, the current density is then reduced to prevent excessive current from causing side reactions of organic matter and reducing the current efficiency. Therefore, in this embodiment, by adjusting the height-diameter ratio, aeration flow rate, and current density, a better degradation efficiency is achieved, and the operating cost is greatly reduced from an economic perspective. Compared with the traditional three-dimensional electrochemical fluidized bed reactor 1 based on mechanical stirring and only aeration, in addition to having a higher current efficiency, the mass transfer and oxidation efficiencies can promote each other, and the conversion efficiency of time and space is greatly improved.

[0070] In a more specific embodiment, a PH sensor is further provided in the reactor 1, and the PH sensor is used to detect the PH value of the wastewater in the reactor 1.

[0071] pH has a significant impact on the generation and stability of some active substances produced during the electrocatalytic process. Hydroxyl radical (·OH) is a very important active substance during the electrocatalytic degradation of organic matter, and its generation is closely related to the concentrations of hydrogen ions and hydroxide ions in the solution. Within an appropriate pH range, it is beneficial to the generation and stable existence of hydroxyl radicals, thereby enhancing the oxidation and degradation ability of organic matter. When the pH is too high or too low, it may lead to the inhibition of the generation of hydroxyl radicals, or cause side reactions with other substances, reducing its degradation effect on organic matter. Therefore, in this example, by monitoring the PH in the wastewater, when the PH is too high or too low, the PH is adjusted by adding drugs to keep the wastewater in the reactor 1 within a reasonable range.

[0072] In a more specific embodiment, a water quality sensor 10 is equipped in the reactor 1. The water quality sensor 10 is used to measure the COD value and pH value of the wastewater in the reactor 1, and its length covers the distribution area of the water outlets 5 at different heights, so as to ensure that the water quality sensor 10 can effectively monitor the wastewater regardless of how the circulating liquid level height of the wastewater in the reactor 1 changes.

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

[0074] It can be understood that in specific implementation, compared with the traditional reactor 1 with two parallel electrode plates as the anode and cathode, the current efficiency and reaction efficiency are greatly improved. The rod-shaped anode is located in the middle, and the electric field is radially distributed from the center to the surroundings. Combined with the surrounding mesh cathode, the distribution of the electric field inside the reactor 1 can be made more uniform, reducing the gradient change of the electric field intensity. In contrast, the electric field between the parallel anode and cathode plates is mainly concentrated in the area opposite to the two plates, and the electric field intensity in the edge area will weaken, resulting in an obvious edge effect and uneven wastewater treatment effect. When adjusting the liquid level height, the rod-shaped anode and mesh cathode structure can better promote the mixing of wastewater in the reactor 1. During the rising process of the bubbles generated by aeration, a more complex flow field will be formed due to the structure of the rod-shaped anode and mesh cathode, enhancing the turbulence degree of the wastewater and enabling the wastewater with different positions and concentrations to be better mixed. This helps to quickly achieve the homogenization of the composition and properties of the wastewater in the entire reactor 1 when the liquid level height changes, improving the organic matter degradation efficiency. In contrast, the mixing effect of the parallel anode and cathode plates on the liquid is relatively weak, and it may take a longer time to achieve a similar mixing effect during the liquid level adjustment process.

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

[0076] Place the stainless steel ring mesh in the glass reaction device, fix the graphite rod anode in the center of the top of the reactor 1 through the foam cotton and insulating rubber band, connect the positive pole of the power supply to the copper rod at the top of the graphite rod electrode, and the negative pole to the top of the stainless steel mesh. By adjusting the voltage and current, the electrocatalytic reaction rate can be changed, thereby generating more ·OH and improving the degradation rate.

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

[0078] It can be understood that in specific implementation, biochar is a product obtained by low-temperature pyrolysis of biomass. Since the organic matter in the biomass is not fully carbonized, some groups are retained, such as carboxyl groups, ketone groups, phenolic groups, quinone groups, hydroquinone groups, etc. These groups retained on the biochar have redox properties, which can realize the functionalization of the biochar. The active sites on the biochar can promote the generation of strongly oxidizing free radicals in the electrocatalytic oxidation system, and the biochar particle electrode is cheap 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 electrode: Rinse the biological raw material (tea leaves), wash off the impurities attached to the surface of the raw material, and put it into the oven for drying until the surface is dry without moisture. Put the washed tea leaves into the grinder and grind them into powder, then take them out, bag them and seal them to keep them dry;

[0081] S12. Pour the shredded biological raw material (tea powder) into the crucible, gently vibrate it to keep the surface of the raw material in the crucible flat, and put it into the muffle furnace for carbonization (while introducing CO2 into the muffle furnace). The operating parameters of the muffle furnace are set as the calcination temperatures of 400 °C, 500 °C, and 600 °C respectively, and the calcination time is 2 h. After the calcination is completed, a total of 3 kinds of BCs (the raw material has 3 temperatures) are obtained. Grind each BC into powder and pass through a 200-mesh sieve to complete the preparation of BC (powdered tea biochar).

[0082] S13. Add 1 g of BC and 0.5 g of CuCl2 to 40 ml of ultrapure water, stir at room temperature for 24 h to adsorb copper ions onto the biochar. After standing for 12 h, adjust the pH to neutral, and then put it into the oven to dry. After drying, put it into the muffle furnace for calcination (while introducing CO2 into the muffle furnace). The operating parameters of the muffle furnace are set as the calcination temperature of 400 °C. After the calcination is completed, grind it and pass through a 200-mesh sieve to complete the preparation of the copper-modified tea biochar particle electrode.

[0083] The embodiment of the present invention also provides a degradation method, including the following steps:

[0084] S01. Before degradation, set the height-to-diameter ratio according to the concentration of organic matter in the wastewater, adjust the liquid level height of the wastewater circulation in the reactor 1, select one of the multiple water outlets 5 to open, and close the other water outlets 5.

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

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

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

[0088] When COD < the third preset value, control the fourth water outlet 54 to open and close the other water outlets 5.

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

[0090] In this embodiment, the diameter of the device is constant, and the height of the reaction volume is adjusted by adjusting the water outlet 5 at different heights, thereby achieving the setting of different height-diameter ratios. In this embodiment, by adjusting the water level height in the reaction vessel according to the concentration of organic matter in the wastewater and reasonably setting the height-diameter ratio according to different wastewater conditions, when facing complex and diverse industrial wastewater, it is beneficial for the reactor 1 to achieve the best degradation rate and effect of organic matter, thereby improving the treatment efficiency of the reaction device for wastewater.

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

[0092] During the reaction process, the concentration of organic matter in the wastewater is monitored in real time. When the concentration of organic matter decreases, that is, when the COD value concentration decreases, if the height-diameter ratio remains unchanged, side reactions are likely to occur, affecting the degradation efficiency of organic matter and wasting electric energy. In this embodiment, by reducing the liquid level, the circulation speed of the wastewater in the reactor 1 can be increased, the current density on the surface of the particle electrode and the collision frequency between the wastewater and the particle electrode can be increased, the mass transfer process can be strengthened, and the degradation of the remaining organic matter can be further promoted; in terms of resource utilization, at different liquid level heights, the working parameters of the electrode, such as the current intensity, can be adjusted according to needs, so that the energy consumption matches the degradation demand of organic matter, avoiding waste of energy and realizing the optimal allocation of resources; in terms of cost, by reasonably adjusting the liquid level, the wastewater treatment efficiency is improved, the residence time of the wastewater in the reactor 1 is reduced, so that the operation time of the equipment can be reduced, energy consumption can be saved, and at the same time, the dynamic adjustment of the liquid level can make the use of the particle electrode more efficient, reduce the loss of the particle electrode caused by too high or too low concentration of organic matter, extend the service life of the particle electrode, reduce the cost of replacing the particle electrode, and thus reduce the overall operation cost.

[0093] It can be understood that during the specific implementation, during the reaction process, the organic matter is decomposed, and after a period of time, the concentration of the organic matter will decrease.

[0094] In a more specific embodiment, step S02 further includes: when the COD value concentration decreases, first reduce the aeration flow rate, and then reduce the water level height in the reactor 1 to prevent the excessive aeration flow rate from flushing the particle electrode above the liquid level height of the reaction solution during the process of reducing the volume in the reactor 1, resulting in waste of the particle electrode.

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

[0096] It can be understood that in specific implementation, on the one hand, reducing the current density can prevent excessive current from causing side reactions of organic substances and reducing the current efficiency; on the other hand, after adjusting the height of the wastewater liquid level in the reactor 1, the current density is reduced. During the adjustment of the height-to-diameter ratio, the change in the liquid level height of the reactor 1 will change the liquid distribution and flow field conditions in the reactor 1, thereby affecting the electric field distribution. An appropriate liquid level circulation height can make the electric field more evenly distributed in the reaction area, ensuring that the particle electrodes can fully play their roles. After optimizing the electric field distribution, the current density is reduced. If the current density is reduced without adjusting the liquid level circulation height, it may lead to too slow reaction in some areas due to uneven electric field distribution, while there is still too high current density in some areas, affecting the overall treatment effect.

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

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

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

[0100] S22. Building of the reactor 1;

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

[0102] S24. Connecting the air inlet at the bottom of the reactor 1 to an oxygen generator so that oxygen flows into the reactor 1 from the bottom for aeration during the operation of the reactor 1, thereby enabling the particle electrodes to fluidize in the reactor 1 device during the reaction.

[0103] S25. Four water outlets 5 with heights of 10 cm, 20 cm, 30 cm, and 40 cm respectively are provided on the right side of the reactor 1, which can be used for three-dimensional electrocatalytic oxidation reactions for reaction liquids with different volumes, realizing a form of multi-purpose in one.

[0104] S26. Inserting the water quality monitor into the reactor 1 from the top opening and turning on the power switch to be able to monitor various water quality parameters in real time during the reaction. The water quality monitor includes a temperature sensor, a pH sensor, and an organic matter concentration sensor;

[0105] S27. After connecting the reaction system, add the reaction liquid, add the particle electrodes, turn on the switch of the peristaltic pump 12 and the valves of the corresponding water outlet 5 and water inlet 4. The reaction device starts fluidization circulation. The water from the water outlet 5 of the device flows into the water tank and then flows into the peristaltic pump 12. Driven by the peristaltic pump 12, it flows to the water inlet 4 and returns to the reactor 1. This process can achieve the adsorption process of the particle electrodes to adsorb and remove pollutants.

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

[0107] The experimental process is as follows:

[0108] Take the wastewater from a pharmaceutical factory and filter the water sample with a 0.45 μm aqueous membrane. The industrial wastewater water sample is detected by a high-performance liquid chromatograph for atrazine (ATZ), nitrobenzene (NB),. After running according to step S26, different operation modes and different height-diameter ratios of the reactor 1 are explored respectively (the dosage of particle electrodes is 1 g / L; the current density is 25 mA / cm2; the gas flow rate is 50 mL / min, the electrolyte is 0.1 M / L sodium sulfate, and the height-diameter ratio is 8:1). From Figure 4 and Figure 5 it can be seen that, compared with two-dimensional electrocatalytic aeration, three-dimensional electrocatalytic aeration, three-dimensional electrocatalytic circulation, and simultaneous three-dimensional electrocatalytic aeration + circulation, in the degradation efficiency of ATZ and NB in the four systems, both aeration and circulation can improve the degradation efficiency of the system, and the best degradation efficiency is achieved when aeration and circulation are carried out simultaneously, with 78.5% degradation of ATZ and 82.3% degradation of NB. From Figure 6 , Figure 7 it can be found that by degrading the solution of different volumes in the reactor 1 to compare the degradation effects of different height-diameter ratios at different height outlets 5, the best degradation effect is achieved at 8:1 (the outlet 5 at 40 cm is the outlet 5). Therefore, at the same organic matter concentration, the larger the height-diameter ratio, the better the effect. Therefore, in this scheme, by setting the outlet 5 at different heights, the height-diameter ratio can be adjusted according to the wastewater situation of different organic matter concentrations before the reaction starts, which is beneficial to achieving the best degradation efficiency.

[0109] Table 1 Water quality of raw water

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

[0111] The above, 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 of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wastewater treatment device, characterized in that, Comprising: A reactor, in which an anode material and a cathode material are arranged, and both the anode material and the cathode material are used for connection to a power source; Both 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, and 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 are located in the reaction area, and are used to adjust the liquid level height of the wastewater in the reactor; The plurality of water outlets are all connected to the water inlet through pipes arranged outside the reactor to realize the circulating flow of the wastewater in the reactor, and an independent first switch is arranged between each water outlet and the water inlet; The water outlet is used to output the wastewater in the reactor, and the water inlet is used to input the wastewater to be treated or the wastewater from the water outlet.

2. The wastewater treatment device according to claim 1, characterized in that, A particle electrode material is arranged 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. An industrial wastewater treatment device according to claim 1 or 2, characterized in that, It 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 switch of each water outlet, the second end of the second switch is connected to the water 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 water inlet of the reactor; The concentration sensor is used to detect the organic matter concentration of the wastewater in the reactor; The second switch is used to connect the water outlet and the water inlet of the reactor and disconnect the connection when the organic matter concentration is reduced to a preset value; The third switch is used to connect the transition container and the reactor when the organic matter concentration is reduced to a preset value, so that part of the wastewater in the reactor flows into the transition container, thereby reducing the wastewater liquid level in the reactor.

4. The wastewater treatment device according to claim 3, characterized in that The transition container is connected to a height regulator, and the height regulator is used to make the height of the transition container change with the switching of the water outlet, so that the liquid level in the transition container is flush with the liquid level in the reactor.

5. A wastewater treatment device according to claim 3, characterized in that, It also includes an aeration device, the bottom of the reactor is connected to the aeration device, and the aeration device is used to input gas into the reactor to generate rising bubbles in the wastewater.

6. An apparatus for treating wastewater according to claim 5, characterized in that, The bottom of the reactor is in a conical shape, which is used to make the particle electrode material falling to the bottom of the reactor slide down along the inclined surface of the cone to the air outlet of the aeration device for fluidization to avoid the accumulation of the particle electrode material at the bottom of the reactor.

7. An industrial wastewater treatment device according to claim 5, characterized in that, The anode material adopts a rod-shaped structure, the anode material is arranged in the center of the reactor, the cathode material adopts a mesh structure, and the cathode material surrounds the outside of the anode material and is arranged close to the inner wall of the reactor.

8. A treatment method of the wastewater treatment device according to any one of claims 1-7, characterized in that, Comprising: S01. Before degradation, set the height-diameter ratio according to the organic matter concentration in the wastewater and adjust the liquid level height of the wastewater circulation in the reactor; S02. During the degradation process, monitor the change of the organic matter concentration in the wastewater. When the organic matter concentration in the wastewater decreases, reduce the height-diameter ratio by reducing the liquid level height of the wastewater circulation in the reactor according to the decrease of the organic matter concentration.

9. A processing method according to claim 8, characterized in that, Step S02 further includes: when the concentration of organic matter in the wastewater decreases, first reducing the aeration flow rate in the reactor, and then reducing the liquid level height of the wastewater circulation in the reactor.

10. A processing method according to claim 9, characterized in that, After step S02 is completed, step S03 is further included: reducing the current density of the cathode material and the anode material.

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