Wastewater treatment system

Abstract

This invention relates to a wastewater treatment system, comprising a pretreatment device, a three-dimensional electrode catalytic oxidation device, a strong oxidation device, and a separation device. The three-dimensional electrode catalytic oxidation device is connected to the pretreatment device. The three-dimensional electrode catalytic oxidation device includes a housing, an anode electrode plate, a cathode electrode plate, a particle electrode assembly, and a light source assembly. The anode and cathode electrode plates are disposed within the housing, and the particle electrode assembly is disposed between the anode and cathode electrode plates. A accommodating space is provided between the anode, cathode, and particle electrode assembly. The light source assembly is disposed within the accommodating space. The surfaces of the cathode electrode plate and the particle electrode assembly are coated with a photocatalytic coating containing a photocatalyst. The strong oxidation device is connected to the three-dimensional electrode catalytic oxidation device, and the separation device is connected to the strong oxidation device. This invention is highly adaptable and can be applied to the treatment of various types of pollutants.

Description

Technical Field

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

[0002] In the petrochemical storage industry, leaks and natural disasters can lead to large-scale chemical spills, resulting in wastewater containing high concentrations of hydrocarbons, phenols, heavy metal ions, and other recalcitrant substances. This poses a serious threat to the environment and human health. Traditional wastewater treatment technologies, such as biological treatment and chemical precipitation, are often ineffective in removing these pollutants and may even cause secondary pollution. Therefore, it is essential to develop a wastewater treatment system that can non-selectively decompose organic molecules, oxidizing and breaking them down into harmless or low-toxic substances. Summary of the Invention

[0003] Therefore, it is necessary to provide a wastewater treatment system to address the problem that wastewater generated by the leakage of stored chemicals contains large amounts of recalcitrant substances such as hydrocarbons, phenols, and heavy metal ions, posing a serious threat to the environment and human health.

[0004] A wastewater treatment system, comprising,

[0005] Pretreatment equipment is used to pretreat wastewater;

[0006] A three-dimensional electrode catalytic oxidation device is used for photoelectric oxidation treatment of pretreated wastewater. The three-dimensional electrode catalytic oxidation device is connected to the pretreatment device. The three-dimensional electrode catalytic oxidation device includes a shell, an anode electrode plate, a cathode electrode plate, a particle electrode assembly, and a light source assembly. The anode electrode plate and the cathode electrode plate are disposed within the shell, and the particle electrode assembly is disposed between the anode electrode plate and the cathode electrode plate. An accommodating space is provided between the anode electrode plate, the cathode electrode plate, and the particle electrode assembly. The light source assembly is disposed within the accommodating space. The surfaces of the cathode electrode plate and the particle electrode assembly are coated with a photocatalytic coating containing a photocatalyst.

[0007] A strong oxidation device is used for strong oxidation treatment of wastewater after photoelectric oxidation treatment; the strong oxidation device is connected to the three-dimensional electrode catalytic oxidation device; and

[0008] A separation device is used to separate solids and liquids in wastewater that has undergone strong oxidation treatment, and the separation device is connected to the strong oxidation device.

[0009] In one embodiment, the particle electrode assembly includes particle electrodes and a filling basket for holding the particle electrodes, the filling basket being a frame basket made of a mesh plate, and the photocatalytic coating being applied to the surface of the filling basket.

[0010] In one embodiment, the particle electrode is columnar activated carbon with a diameter of 2-3 mm and a height of 5-6 mm; the mesh plate has a mesh size of 2 mm * 2 mm.

[0011] In one embodiment, the light source assembly includes a quartz tube and an ultraviolet lamp. The quartz tube is vertically disposed within the accommodating space, with its upper end extending upward through the housing. The bottom of the quartz tube is sealed to the housing, and the ultraviolet lamp is vertically disposed inside the quartz tube.

[0012] In one embodiment, the three-dimensional electrode catalytic oxidation device further includes a water inlet pipe and an aeration pipe, which are located at the bottom of the shell. The water inlet pipe is connected to the pretreatment device and has a water inlet hole along its length. The aeration pipe is connected to an external air pump and has an aeration hole along its length.

[0013] In one embodiment, the strong oxidation device includes a housing, a photocatalytic plate, an ultraviolet light source assembly, and a drug supply assembly. The housing is cylindrical in shape, the photocatalytic plate is fixed to the inner circumferential wall of the housing, the ultraviolet light source assembly is located in the middle of the housing, and a drug inlet is provided at the upper end of the housing, which is connected to the drug supply assembly.

[0014] In one embodiment, the photocatalytic plate is made of titanium metal, and the surface of the photocatalytic plate is coated with a photocatalytic coating containing a photocatalyst.

[0015] In one embodiment, the photocatalyst is modified titanium dioxide doped with ferric ions or modified titanium dioxide doped with conductive graphene.

[0016] In one embodiment, the drug supply assembly includes a drug tank, a drug supply pump, a drug supply valve, and a drug supply flow meter. The drug inlet is connected to the drug tank via the drug supply pump. The drug supply valve and the drug supply flow meter are located between the drug supply pump and the outer casing. The drug tank stores hydrogen peroxide.

[0017] In one embodiment, the wastewater treatment system further includes a water storage tank, a water quality detector, an output pump, a switching valve, and a controller. The water storage tank is connected to the separation device, the water quality detector is located in the water storage tank, the inlet of the switching valve is connected to the water storage tank, one outlet of the switching valve is connected to an external connecting pipe, the other outlet of the switching valve is connected to the three-dimensional electrode catalytic oxidation device, the water quality detector is communicatively connected to the controller, and the output pump and the switching valve are electrically connected to the controller.

[0018] The beneficial effects of this invention are as follows: By employing a combination of three-dimensional electrodes and enhanced oxidation technology, a highly efficient and environmentally friendly wastewater treatment system is constructed. Under photocatalysis, a large number of free radicals (such as ·OH) can be generated. These free radicals can non-selectively attack and decompose organic molecules, causing them to be oxidized and decomposed into harmless or low-toxic substances. This system can treat large quantities of high-concentration, multi-component wastewater in a short period of time. The wastewater treatment system described in this invention is highly adaptable and can be applied to the treatment of various types of pollutants. It can be used as a deep treatment technology for recalcitrant phenolic wastewater, or as a pretreatment measure for recalcitrant wastewater to improve its biodegradability, combined with traditional biological treatment methods to reduce treatment costs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a sewage treatment system according to one embodiment of the present invention;

[0020] Figure 2 This is an assembly structure diagram of the pretreatment device in the wastewater treatment system of the present invention;

[0021] Figure 3 This is a schematic diagram of the internal structure of the three-dimensional electrode catalytic oxidation device in the wastewater treatment system of the present invention.

[0022] Figure 4 This is a top view schematic diagram of the internal structure of the three-dimensional electrode catalytic oxidation device in the wastewater treatment system of the present invention.

[0023] Figure 5 This is a schematic diagram of the internal structure of the strong oxidation device in the wastewater treatment system of the present invention.

[0024] The meanings of the numbers in the attached diagram are as follows:

[0025] 100 - Wastewater treatment system;

[0026] 10-Pretreatment device, 11-Equalization tank, 12-Grate, 13-Sedimentation tank, 14-Dosing mechanism, 141-Dosing pipe, 142-Dosing pump, 143-Drug storage tank, 144-Dosing valve, 145-Dosing flow meter, 15-First pH sensor;

[0027] 20-Three-dimensional electrode catalytic oxidation device, 21-Shell, 22-Anode electrode plate, 23-Cathode electrode plate, 24-Particle electrode assembly, 241-Filling basket, 242-Particle electrode, 25-Light source assembly, 251-Quartz tube, 252-Ultraviolet lamp, 26-Water inlet pipe, 261-Water inlet hole, 27-Aeration pipe, 271-Aeration hole, 28-Accommodation space;

[0028] 30-Strong oxidizing device, 31-Outer shell, 32-Photocatalytic plate, 33-Ultraviolet light source assembly, 331-Quartz tube, 332-Ultraviolet lamp, 34-Drug supply assembly, 341-Drug tank, 342-Drug supply pump, 343-Drug supply valve, 344-Drug supply flow meter, 35-Second pH sensor;

[0029] 40 - Separation device;

[0030] 50 - Transfer pump;

[0031] 60 - Transfer pump;

[0032] 70 - Pumping pump;

[0033] 80 - Output pump;

[0034] 90 - Switching valve;

[0035] 110 - Water storage tank;

[0036] 120 - Water quality detector. Detailed Implementation

[0037] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0042] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0043] Please see Figure 1 The wastewater treatment system 100 according to one embodiment of the present invention includes a pretreatment device 10, a three-dimensional electrode catalytic oxidation device 20, a strong oxidation device 30, and a separation device 40. The pretreatment device 10 is used to pretreat wastewater. The three-dimensional electrode catalytic oxidation device 20 is connected to the pretreatment device 10, the strong oxidation device 30 is connected to the three-dimensional electrode catalytic oxidation device 20, and the separation device 40 is connected to the strong oxidation device 30.

[0044] Please see Figure 2The pretreatment device 10 includes an equalization tank 11, a bar screen 12, a sedimentation tank 13, and a dosing mechanism 14. The equalization tank 11 is provided with an inlet and an outlet. The bar screen 12 is located at the outlet, and the outlet is connected to the sedimentation tank 13. The equalization tank 11 is provided with a dosing port, which is connected to the dosing mechanism 14. The dosing mechanism 14 includes a dosing pipe 141, a dosing pump 142, a drug storage tank 143, a dosing valve 144, and a dosing flow meter 145. The dosing pump 142 is connected to the dosing port through the dosing pipe 141 and is also connected to the dosing storage tank. The dosing valve 144 and the dosing flow meter 145 are located between the dosing pump 142 and the regulating tank 11. In this embodiment, there are two dosing mechanisms 14. One dosing mechanism 14 has a drug storage tank 143 that mainly stores sodium hydroxide solution, and the other dosing mechanism 14 has a drug storage tank 143 that mainly stores hydrochloric acid solution.

[0045] During operation, wastewater enters the equalization tank 11 through the inlet. The pH value of the wastewater is adjusted by the dosing mechanism 14 to reach 7. Large particulate impurities are removed by the screen 12, and then the wastewater enters the sedimentation tank 13 to remove suspended solids and some oily substances, thereby stabilizing the water quality of the wastewater.

[0046] Please see Figure 1 The wastewater treatment system 100 also includes a transfer pump 50, which is located between the sedimentation tank 13 and the three-dimensional electrode catalytic oxidation device 20, and is mainly used to transfer the wastewater in the sedimentation tank 13 to the three-dimensional electrode catalytic device.

[0047] Please see Figure 3 and Figure 4 The three-dimensional electrode catalytic device includes a housing 21, an anode electrode plate 22, a cathode electrode plate 23, a particle electrode assembly 24, a light source assembly 25, a water inlet pipe 26, and an aeration pipe 27. The inner wall of the housing 21 is provided with an anode slot and a cathode slot. The anode electrode plate 22 is inserted into the anode slot, and the cathode electrode plate 23 is inserted into the cathode slot. The anode electrode plate 22 is made of pressed natural graphite flat plate, and the cathode electrode plate 23 is made of titanium plate. The outer wall of the cathode electrode plate 23 is coated with a photocatalytic coating containing a photocatalyst, which is modified titanium dioxide doped with ferric ions or modified titanium dioxide doped with conductive graphene. In this embodiment, there are two anode electrode plates 22 and two cathode electrode plates 23, which are arranged parallel to each other and alternately.

[0048] Please see Figure 3 and Figure 4The particle electrode assembly 24 is disposed between the anode electrode plate 22 and the cathode electrode plate 23. The particle electrode assembly 24 includes a particle electrode 242 and a filling basket 241 for holding the particle electrode 242. The particle electrode 242 is columnar activated carbon with a diameter of 2-3 mm and a height of 5-6 mm. The filling basket 241 is fixedly disposed on the inner wall of the housing 21. The side end of the filling basket 241 does not contact the anode electrode plate 22 or the cathode electrode plate 23, thus effectively preventing short circuits caused by contact between the particle electrode assembly 24 and the anode electrode plate 22 and the cathode electrode plate 23. An opening is provided at the top of the filling basket 241, through which the particle electrode 242 is inserted into the filling basket 241. The filling basket 241 is a frame basket made of a mesh plate with mesh holes of 2mm*2mm. The mesh plate is made of titanium metal and the outer wall of the mesh plate is coated with a photocatalytic coating. The photocatalytic coating contains a photocatalyst, which is modified titanium dioxide doped with ferric ions or modified titanium dioxide doped with conductive graphene.

[0049] Please see Figure 3 and Figure 4 A receiving space 28 is provided between the anode electrode plate 22, the cathode electrode plate 23, and the particle electrode assembly 24. The light source assembly 25 is disposed within the receiving space 28. The light source assembly 25 includes a quartz tube 251 and an ultraviolet lamp 252. The quartz tube 251 is vertically disposed within the receiving space 28, with its upper end extending upwards through the housing 21. The bottom of the quartz tube 251 is sealed to the housing 21. The ultraviolet lamp 252 is vertically disposed within the quartz tube 251, thus ensuring that sewage does not enter the quartz tube 251 and that the ultraviolet lamp 252 does not short-circuit. The water inlet pipe 26 and the aeration pipe 27 are located at the bottom of the housing 21. The water inlet pipe 26 is connected to the delivery pump 50, and the water inlet pipe 26 has a water inlet hole 261 along its length. The aeration pipe 27 is connected to an external air pump, and the aeration pipe 27 is provided with aeration holes 271 along its length. A sewage pipe is provided on the bottom side wall of the shell 21.

[0050] During operation, wastewater enters the housing 21 through the inlet pipe 26. The anode electrode plate 22 is electrically connected to the positive terminal of the power supply, and the cathode electrode plate 23 is electrically connected to the negative terminal. During electrolysis, the cathode electrode plate 23 releases electrons, causing the cations in the wastewater to be reduced by gaining electrons; the anode electrode plate 22 gains electrons, causing the anions in the wastewater to lose electrons and be oxidized. In this way, some harmful substances in the wastewater are removed while free radicals are generated. The ultraviolet light emitted by the ultraviolet lamp 252 irradiates the cathode electrode plate 23 and the filling basket 241, causing the photocatalyst on its surface to generate a large number of free radicals, which oxidize and decompose some organic matter in the wastewater. At the same time, the aeration pipe 27 provides sufficient dissolved oxygen, effectively promoting the efficiency of the photocatalytic reaction.

[0051] Please see Figure 1 The wastewater treatment system 100 also includes a transfer pump 60, which is located between the three-dimensional electrode catalytic device and the strong oxidation device 30. The transfer pump 60 is connected to the sewage pipe through a conduit and is mainly used to transfer the wastewater after photoelectro-oxidation reaction to the strong oxidation device 30.

[0052] Please see Figure 5 The strong oxidation device 30 includes a housing 31, a photocatalytic plate 32, an ultraviolet light source assembly 33, and a drug supply assembly 34. The housing 31 has a cylindrical structure and an inlet at its upper end. The inlet is connected to the transfer pump 60 via a conduit. The photocatalytic plate 32 is fixedly disposed on the inner wall of the housing 31 and is located around the circumference of the housing 31. The photocatalytic plate 32 is made of titanium and its surface is coated with a photocatalytic coating containing a photocatalyst. The photocatalyst is modified titanium dioxide doped with ferric ions or modified titanium dioxide doped with conductive graphene. The ultraviolet light source assembly 33 includes a quartz tube 331 and an ultraviolet lamp 332. The quartz tube 331 is vertically disposed in the middle of the outer casing 31, with its upper end extending upwards out of the outer casing 31 and its bottom sealed to the outer casing 31. The ultraviolet lamp 332 is vertically disposed inside the quartz tube 331. Due to the cylindrical structure of the outer casing 31 and the vertical placement of the ultraviolet lamp 332 inside the quartz tube 331, the ultraviolet light emitted by the ultraviolet lamp 332 can fully cover the photocatalyst plate 32, effectively increasing the contact area between light and the photocatalyst.

[0053] Please see Figure 5The upper end of the outer shell 31 is provided with a drug inlet, which is connected to the drug supply component 34. The drug supply component 34 includes a drug tank 341, a drug supply pump 342, a drug supply valve 343, and a drug supply flow meter 344. The drug inlet is connected to the drug tank 341 through the drug supply pump 342. The drug supply valve 343 and the drug supply flow meter 344 are located between the drug supply pump 342 and the outer shell 31. The drug tank 341 stores hydrogen peroxide.

[0054] During operation, wastewater enters the outer shell 31 through the inlet, while hydrogen peroxide enters the outer shell 31 through the inlet, adjusting the pH value of the wastewater inside the outer shell 31 to 4. Under the ultraviolet light emitted by the ultraviolet lamp, the photocatalytic plate 32 is irradiated. Under photocatalytic action and acidic conditions, hydrogen peroxide is decomposed to produce hydroxyl radicals (·OH) with extremely strong oxidizing power. Hydroxyl radicals can attack and destroy the molecular structure of pollutants, causing them to be oxidized and decomposed into harmless or low-toxic substances.

[0055] Please see Figure 1 The wastewater treatment system 100 also includes a pumping pump 70, and an outlet is provided at the bottom side of the housing 31. The outlet is connected to the separation device 40 through the pumping pump 70.

[0056] Please see Figure 1 The separation device 40 is used to separate solids and liquids in wastewater after enhanced oxidation treatment. It typically removes precipitates or suspended solids generated in the three-dimensional electrode catalytic oxidation device 20 and the strong oxidation device 30 by means of sedimentation, filtration or centrifugation.

[0057] Please see Figure 1 The wastewater treatment system 100 also includes a water storage tank 110, which is connected to the separation device 40. After the wastewater undergoes enhanced oxidation treatment, the liquid after solid-liquid separation in the separation device 40 enters the water storage tank 110.

[0058] Please see Figure 1 , Figure 2 and Figure 5 The wastewater treatment system 100 also includes a pH sensor and a controller. There are two pH sensors, including a first pH sensor 15 and a second pH sensor 35. The first pH sensor 15 is located in the equalization tank 11, and the second pH sensor 35 is located in the housing 31. Both the first pH sensor 15 and the second pH sensor 35 are communicatively connected to the controller. The chemical supply pump 342, the pumping pump 70, and the two chemical dosing pumps 142 are electrically connected to the controller.

[0059] Please see Figure 1 , Figure 2 and Figure 5The controller controls the two dosing pumps 142 to operate based on the pH value detected by the first pH sensor 15, so as to automatically adjust the pH value of the sewage in the equalization tank 11 to 7. This provides a more stable water quality for subsequent sewage treatment, effectively reduces the corrosive effect of sewage on the pipes, and effectively extends the service life of each pipe in the sewage treatment system 100.

[0060] Before the strong oxidation device 30 starts working, the controller controls the operation of the chemical supply pump 342 based on the pH value detected by the second pH sensor 35, so as to automatically adjust the pH value of the sewage in the shell 31 to 4. This allows for dynamic adjustment of the amount of hydrogen peroxide added, effectively improving the sewage treatment effect while controlling the sewage treatment cost.

[0061] During the operation of the strong oxidation device 30, the controller controls the pump 70 based on the pH value detected by the second pH sensor 35 to determine whether the reaction inside the housing 31 is complete. Generally, when the pH value detected by the second pH sensor 35 is close to 7, it can be determined that the reaction inside the housing 31 is complete, that is, the strong oxidation treatment step is completed. The controller then controls the pump 70 to send the wastewater after the enhanced oxidation treatment into the separation device 40.

[0062] Please see Figure 1 The wastewater treatment system 100 also includes a water quality detector 120, an output pump 80, and a switching valve 90. The water quality detector 120 is located in the water storage tank 110 and is communicatively connected to the controller. The output pump 80 is connected to the water storage tank 110. The inlet of the switching valve 90 is connected to the output pump 80. One outlet of the switching valve 90 is connected to an external connecting pipe, and the other outlet of the switching valve 90 is connected to the inlet pipe 26. Both the output pump 80 and the switching valve 90 are electrically connected to the controller.

[0063] When the water quality information detected by the water quality detector 120 meets the requirements, the controller controls the output pump 80 to work and switches the switching valve 90 to connect the water storage tank 110 to the external connection pipe. Through the external connection pipe, the liquid can be discharged or enter the biological filter for deep treatment.

[0064] When the water quality information detected by the water quality detector 120 does not meet the requirements, the controller controls the output pump 80 to operate and switches the switching valve 90 to connect the water storage tank 110 to the inlet pipe 26. This allows the water in the water storage tank 110 to re-enter the three-dimensional electrode catalytic device and the strong oxidation device 30 for treatment. This results in a higher degree of automation in the wastewater treatment system 100, making it easier for operators to use, and also improving the wastewater treatment effect.

[0065] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0066] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A wastewater treatment system, characterized in that, include, A pretreatment device for pretreating wastewater includes an equalization tank, a screen, a sedimentation tank, and a dosing mechanism. The equalization tank is equipped with a first pH sensor, an inlet, and an outlet. The screen is located at the outlet, which is connected to the sedimentation tank. The equalization tank has a dosing port connected to the dosing mechanism. The dosing mechanism includes a dosing pipe, a dosing pump, a chemical storage tank, a dosing valve, and a flow meter. The dosing pump is connected to the dosing port via the dosing pipe and is also connected to the chemical storage tank. The dosing valve and flow meter are located between the dosing pump and the equalization tank. There are two dosing mechanisms; one mechanism's chemical storage tank primarily stores sodium hydroxide solution, and the other mechanism's chemical storage tank primarily stores hydrochloric acid solution. (Three-dimensional electrode) A catalytic oxidation device is used for photoelectric oxidation treatment of pretreated wastewater. The three-dimensional electrode catalytic oxidation device is connected to the pretreatment device. The three-dimensional electrode catalytic oxidation device includes a shell, an anode electrode plate, a cathode electrode plate, a particle electrode assembly, and a light source assembly. The anode electrode plate and the cathode electrode plate are disposed within the shell. The particle electrode assembly is disposed between the anode electrode plate and the cathode electrode plate. The particle electrode assembly includes particle electrodes and a filling basket for holding the particle electrodes. The side end of the filling basket does not contact the anode electrode plate and the cathode electrode plate. An accommodating space is provided between the anode electrode plate, the cathode electrode plate, and the particle electrode assembly. The light source assembly is disposed within the accommodating space. The surfaces of the cathode electrode plate and the particle electrode assembly are coated with a photocatalytic coating containing a photocatalyst. A strong oxidation device is used for strong oxidation treatment of wastewater after photoelectric oxidation treatment. The strong oxidation device is connected to a three-dimensional electrode catalytic oxidation device. The strong oxidation device includes a shell, a photocatalytic plate, an ultraviolet light source assembly, and a drug supply assembly. The shell has a cylindrical structure and a second pH sensor is installed inside the shell. An outlet is provided at the bottom side of the shell. The photocatalytic plate is fixed to the circumferential inner wall of the shell. The ultraviolet light source assembly is located in the middle of the shell. A drug inlet is provided at the upper end of the shell and is connected to the drug supply assembly. The drug supply assembly includes a drug tank, a drug pump, a drug valve, and a drug flow meter. The drug inlet is connected to the drug tank through the drug pump. The drug valve and the drug flow meter are located between the drug pump and the shell. The drug tank stores hydrogen peroxide. A separation device is used to separate solids and liquids in wastewater that has undergone strong oxidation treatment, and the separation device is connected to the strong oxidation device. A pump is provided, and the outlet is connected to the separation device via the pump. as well as The controller is communicatively connected to the first pH sensor and the second pH sensor, and the dosing pump, the supply pump and the pumping pump are all electrically connected to the controller.

2. The wastewater treatment system according to claim 1, characterized in that, The particle electrode assembly includes particle electrodes and a filling basket for holding the particle electrodes. The filling basket is a frame basket made of a mesh plate, and the photocatalytic coating is applied to the surface of the filling basket.

3. The wastewater treatment system according to claim 2, characterized in that, The particle electrode is columnar activated carbon with a diameter of 2-3 mm and a height of 5-6 mm; the mesh plate has a mesh size of 2 mm * 2 mm.

4. The wastewater treatment system according to claim 3, characterized in that, The light source assembly includes a quartz tube and an ultraviolet lamp. The quartz tube is vertically arranged in the accommodating space, with its upper end extending upwards out of the housing. The bottom of the quartz tube is sealed to the housing, and the ultraviolet lamp is vertically arranged inside the quartz tube.

5. The wastewater treatment system according to claim 4, characterized in that, The three-dimensional electrode catalytic oxidation device also includes a water inlet pipe and an aeration pipe. The water inlet pipe and the aeration pipe are located at the bottom of the shell. The water inlet pipe is connected to the pretreatment device and has a water inlet hole along its length. The aeration pipe is connected to an external air pump and has aeration holes along its length.

6. The wastewater treatment system according to claim 1, characterized in that, The photocatalytic plate is made of titanium metal, and its surface is coated with a photocatalytic coating containing a photocatalyst.

7. The wastewater treatment system according to claim 1 or 6, characterized in that, The photocatalyst is modified titanium dioxide doped with ferric ions or modified titanium dioxide doped with conductive graphene.

8. The wastewater treatment system according to claim 1, characterized in that, It also includes a water storage tank, a water quality detector, an output pump, and a switching valve. The water storage tank is connected to the separation device. The water quality detector is located in the water storage tank. The inlet of the switching valve is connected to the water storage tank. One outlet of the switching valve is connected to an external connecting pipe. The other outlet of the switching valve is connected to the three-dimensional electrode catalytic oxidation device. The water quality detector is communicatively connected to the controller. The output pump and the switching valve are electrically connected to the controller.

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