A wastewater treatment system and method with coupled filtration, electro-oxidation, and electro-reduction functions.

Abstract

This invention belongs to the field of water treatment technology, specifically a wastewater treatment system with coupled filtration, electro-oxidation, and electro-reduction functions. It includes a raw water tank, a wastewater lift pump, an electrochemical reaction tank, a DC regulated power supply, a purified water tank, a wastewater return pump, a backwash tank, and a supporting pipeline system. The electrochemical reaction tank is a rectangular semi-enclosed tank made of non-conductive material, containing multiple stacked open-type filtration electrochemical reaction modules and a water distributor connecting the reaction modules. The wastewater treatment system simultaneously uses porous cathodes and porous anodes as filtration cathodes and anodes, respectively, giving the reaction system diversified treatment capabilities. Oxidizable pollutants in the wastewater are oxidized and removed in the anode reaction area, while reducible pollutants are reduced and removed in the cathode reaction area.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically a wastewater treatment system and method that couples filtration, electro-oxidation, and electro-reduction functions. Background Technology

[0002] Electrochemical filtration water treatment technology is an advanced oxidation water treatment technology for wastewater treatment. This technology forces wastewater through a porous anode or cathode in a filtration mode, enhancing the mass transfer and diffusion process of pollutants from the main wastewater to the electrode interface reaction zone, overcoming the limitation of limited mass transfer in traditional co-current systems. Compared with traditional co-current electrochemical water treatment systems, filtration-based electrochemical water treatment systems can increase the pollutant removal rate by several to tens of times, thereby significantly improving the efficiency and energy efficiency of electrochemical water treatment.

[0003] However, the aforementioned technologies often suffer from the following drawbacks: Current filtration-based electrochemical water treatment technologies primarily focus on treating wastewater through a single electrode reaction process, namely filtration anodizing or filtration cathodic reduction. A single reaction process typically targets only a single type of pollutant in the water; for example, filtration anodizing usually only degrades organic pollutants, while filtration cathodic reduction can reduce nitrate nitrogen or halogenated disinfection byproducts. However, actual wastewater is usually complex, typically containing organic pollutants, ammonia nitrogen, nitrate nitrogen, and other contaminants. Furthermore, current open-type filtration electrochemical reaction modules typically employ fully enclosed reactors, meaning the filter electrodes are completely sealed. This can not only exacerbate irreversible clogging of the filter electrode material but also lead to material waste due to the incomplete utilization of the reactive surface areas of the filter electrode material. In addition, during operation, filtration-based electrochemical water treatment systems typically require a relatively low influent flow rate to achieve better effluent quality. When the influent flow rate is low, the mass transfer rate of the wastewater treatment system will be greatly reduced, thereby weakening the overall treatment efficiency of the wastewater treatment system. Although increasing the water flux can improve the mass transfer efficiency, this will result in a short contact time between the wastewater and the electrode reaction area, and insufficient wastewater reaction, thus causing the effluent water quality to deteriorate. Therefore, this invention provides a wastewater treatment system and method with coupled filtration electro-oxidation and electro-reduction functions. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0005] The technical solution adopted by the present invention to solve its technical problem is as follows: The wastewater treatment system of the present invention with coupled filtration electro-oxidation-electro-reduction function includes a raw water tank, a sewage lift pump, an electrochemical reaction tank, a DC regulated power supply, a clean water tank, a sewage return pump, a backwash water tank and a supporting pipe network system; the electrochemical reaction tank is a rectangular semi-enclosed tank made of non-conductive material, which contains multiple stacked open filtration electrochemical reaction modules and a water distributor connecting the reaction modules. The electrochemical reaction tank is provided with an inlet, a first outlet, an internal circulation return port, an air outlet and an air drain valve provided on the air outlet.

[0006] Preferably, the open-type filter electrochemical reaction module is connected in parallel with a DC regulated power supply via an anode wire and a cathode wire; the stacked open-type filter electrochemical reaction module is fixed in the electrochemical reaction tank by a fixed bracket made of non-conductive material.

[0007] Preferably, the first water outlet is located near the top of the electrochemical reaction tank, above the open-type filter electrochemical reaction module, and the first water outlet, the internal circulation return port, and the vent are located at the bottom of the electrochemical reaction tank.

[0008] Preferably, the open-type filtration electrochemical reaction module consists of a porous cathode and a porous anode with similar pore sizes, corresponding cathode terminals and anode terminals, and a sealing flange made of non-conductive material. The sealing flange is provided with a second water outlet connected to the water distributor.

[0009] Preferably, the supporting pipeline system is equipped with a first flow meter and a second flow meter. The first flow meter is used to monitor the inlet water flow, and the second flow meter is used to monitor the internal circulation flow. The supporting pipeline system is equipped with a pressure gauge to monitor the pressure of the open filter electrochemical reaction module during the internal circulation process and the backwashing process. The supporting pipeline system is equipped with first and second valves to control the internal circulation process and the backwashing process.

[0010] Preferably, a hollow plate is fixedly connected to the bottom surface of the sealing flange, and water outlet holes are provided on both sides of the hollow plate. A sealing component for sealing the water outlet holes is provided inside the hollow plate. A round pipe is connected to the top of the hollow plate. A sliding groove is provided inside the round pipe. A connecting pipe is slidably connected to the sliding groove. A sealing ring is fixedly connected to the side wall of the connecting pipe. A driving component for driving the connecting pipe to move upward is provided inside the hollow plate.

[0011] Preferably, the driving assembly includes a float block slidably connected to the side wall of the hollow plate, a connecting plate fixedly connected to the side wall of the hollow plate, a hollow elastic plate fixedly connected to the top surface of the connecting plate, a set of connecting grooves opened in the hollow plate, one end of the connecting groove communicating with the sliding groove, and the other end communicating with the interior of the elastic plate, a sealing plate being twisted to the bottom end of the round tube by a torsion spring, and a connecting line being fixedly connected between the top surface of the sealing plate and the inner wall of the connecting tube.

[0012] Preferably, the sealing assembly includes a movable plate that is slidably connected to the inner wall of the hollow plate. The movable plate has a hollow structure and an opening at the top. Both sides of the movable plate have connection holes corresponding to the water outlet holes. A spring is fixedly connected between the bottom surface of the movable plate and the inner wall of the hollow plate.

[0013] A wastewater treatment method with coupled filtration, electro-oxidation, and electro-reduction functions, employing the aforementioned wastewater treatment system with coupled filtration, electro-oxidation, and electro-reduction functions, includes the following steps:

[0014] S1: When the wastewater treatment system is running, the wastewater return flow rate is preset, and the drain valve and the second valve are closed. Under the action of the wastewater lift pump, the wastewater enters the electrochemical reaction tank through the inlet set at the bottom of the electrochemical reaction tank.

[0015] S2: Turn on the sewage return pump and the first valve. The sewage return pump provides suction to the open filtration electrochemical reaction module, driving sewage to continuously pass through the porous anode and porous cathode into the open filtration electrochemical reaction module.

[0016] S3: The wastewater then returns to the electrochemical reaction tank through the water distributor and internal circulation return port of the connected reaction module, realizing the internal circulation process of wastewater. The wastewater inflow rate can be adjusted by controlling the wastewater lift pump, and the mass transfer efficiency of pollutants in the wastewater to the reaction area on the electrode surface can be adjusted by controlling the wastewater return pump.

[0017] S4: When the pressure gauge detects a 50% increase in the pressure of the wastewater treatment system, shut down the wastewater lift pump and the DC regulated power supply, open the drain valve to drain the wastewater in the electrochemical reaction tank; perform a backwashing operation, keeping the drain valve open, reverse the wastewater return pump, and use the pure water in the backwash tank to rinse the open-type filter electrochemical reaction module.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. The present invention employs a wastewater treatment system, which simultaneously uses porous cathodes and porous anodes as filter cathodes and filter anodes respectively, enabling the reaction system to have diversified treatment capabilities. Pollutants in the wastewater that can be oxidized are oxidized and removed in the filter anode reaction area, while pollutants in the wastewater that can be reduced are reduced and removed in the filter cathode reaction area.

[0020] 2. To address the issues of insufficient treatment capacity at low flow rates and deterioration of effluent quality at high flow rates, this invention employs an internal circulation design to ensure that wastewater always passes through the microporous structure of the filter electrode at a high speed, thereby enhancing the mass transfer process of pollutants in the wastewater to the electrode surface. The open-type filter electrochemical reaction module is stacked in a "cathode-anode-cathode...anode-cathode-anode" pattern. This method fully utilizes the reactive areas on both sides of the porous cathode and porous anode, improving the utilization rate of electrode materials.

[0021] 3. To address the problem of irreversible pore blockage of filter electrodes in existing filtration-type electrochemical water treatment systems, this invention designs an open-type filtration electrochemical reaction module. In this module, the porous anode and cathode are in direct contact with the main wastewater, and the wastewater is driven through the module by suction and then flows out. This process can trap larger suspended solids in the wastewater within the main wastewater, preventing them from entering the reaction system. Simultaneously, a backwashing system is designed to perform backwashing when the reaction system operating pressure is abnormal, flushing away the suspended solids clogging the micropores of the porous anode and cathode. Attached Figure Description

[0022] The invention will now be further described with reference to the accompanying drawings.

[0023] Figure 1 This is a schematic diagram of the wastewater treatment system in this invention;

[0024] Figure 2 This is a schematic diagram of the internal structure of the electrochemical reaction tank of the present invention;

[0025] Figure 3 This is a schematic diagram of the structure of the open-type filter electrochemical reaction module in this invention;

[0026] Figure 4 This is a schematic diagram of the internal structure of the open-type filter electrochemical reaction module in this invention;

[0027] Figure 5 This is a schematic diagram of the wastewater treatment system in Example 2 of the present invention, which simultaneously removes the antibiotic sulfamethoxazole and nitrate nitrogen from the water.

[0028] Figure 6 This is a schematic diagram of the wastewater treatment system in this invention treating biochemical effluent from landfill leachate;

[0029] Figure 7 This is a schematic diagram of the hollow plate structure within the open-type filter electrochemical reaction module of the present invention;

[0030] Figure 8 yes Figure 7 Enlarged view of point A;

[0031] Figure 9 This is a flowchart of the method in this invention.

[0032] In the diagram: 1. Raw water tank; 2. Sewage lift pump; 3. Electrochemical reaction tank; 4. DC regulated power supply; 5. Purified water tank; 6. Sewage return pump; 7. Backwash tank; 8. Supporting pipeline system; 9. Open-type filtration electrochemical reaction module; 10. Water distributor; 11. Inlet; 12. First outlet; 13. Internal circulation return port; 14. Drain port; 15. Drain valve; 16. Anode conductor; 17. Cathode conductor; 18. Fixed bracket; 19. First flow meter; 20. Second... Flow meter; 21. Pressure gauge; 22. First valve; 23. Second valve; 24. Porous cathode; 25. Porous anode; 26. Cathode terminal; 27. Anode terminal; 28. Sealing flange; 29. ​​Second outlet; 30. Hollow plate; 31. Outlet hole; 32. Circular pipe; 33. Slide groove; 34. Connecting pipe; 35. Sealing ring; 36. Connecting wire; 37. Moving plate; 38. Connecting hole; 39. Elastic plate; 40. Connecting plate; 41. Float; 42. Connecting groove. Detailed Implementation

[0033] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0034] Example 1: As Figures 1 to 4 As shown in the embodiment of the present invention, a wastewater treatment system with coupled electro-oxidation and electro-reduction functions includes a raw water tank 1, a sewage lift pump 2, an electrochemical reaction tank 3, a DC regulated power supply 4, a purified water tank 5, a sewage return pump 6, a backwash water tank 7, and a supporting pipeline system 8. The electrochemical reaction tank 3 is a rectangular semi-enclosed tank made of non-conductive material, which contains multiple stacked open-type electrochemical reaction modules 9 and a water distributor 10 connecting the reaction modules. The electrochemical reaction tank 3 is provided with an inlet 11, a first outlet 12, an internal circulation return port 13, an air outlet 14, and an air outlet valve 15 provided on the air outlet 14.

[0035] The open-type filter electrochemical reaction module 9 is connected in parallel with the DC regulated power supply 4 via an anode wire 16 and a cathode wire 17. The stacked open-type filter electrochemical reaction modules 9 are fixed in the electrochemical reaction tank 3 by a non-conductive fixing bracket 18. Each open-type filter electrochemical reaction module 9 is arranged in parallel, and the overall porous electrode is installed in the pattern of "cathode-anode-cathode...anode-cathode-anode" with a spacing of 0.5-5 cm.

[0036] The first water outlet 12 is located near the top of the electrochemical reaction tank 3, above the open-type filter electrochemical reaction module 9. The first water outlet 12, the internal circulation return port 13, and the drain port 14 are located at the bottom of the electrochemical reaction tank 3.

[0037] The open-type filtration electrochemical reaction module 9 consists of a porous cathode 24 and a porous anode 25 with similar pore sizes, corresponding cathode terminals 26 and anode terminals 27, and a non-conductive sealing flange 28. The sealing flange 28 is provided with a second outlet 29 connected to the water distributor 10. The non-conductive sealing flange 28 only covers the edge of the porous cathode 24 and porous anode 25, ensuring that most of the surface of the porous cathode 24 and porous anode 25 can directly contact the main sewage. The pore size of the filter anode and filter cathode is 0.5-100μm.

[0038] The porous anode 25 and porous cathode 24 in the same wastewater treatment system have similar pore sizes to ensure uniform pressure distribution at the interface between the cathode side and the anode side of the open filtration electrochemical reaction module 9 and the wastewater, thereby ensuring that the wastewater enters the open filtration electrochemical reaction module 9 uniformly from the cathode side and the anode side; the distance between the plates of the porous anode 25 and porous cathode 24 in the open filtration electrochemical reaction module 9 is set to 0.5-5 cm.

[0039] The porous anode 25 can be made of antimony-doped tin dioxide, lead dioxide, ruthenium-iridium, titanium suboxide, or derivative electrode materials prepared by doping with rare earth elements or noble metal elements; the porous cathode 24 can be made of metal oxide, conductive carbon, titanium suboxide, noble metal, or derivative electrode materials prepared by doping with rare earth elements or noble metal elements; the DC regulated power supply 4 has an input current density of 1–50 mA / cm². ‒2 The current density is calculated based on the total area of ​​the porous anode 25 or porous cathode 24 in the open-loop filter electrochemical reaction module 9.

[0040] The supporting pipeline system 8 is equipped with a first flow meter 19 and a second flow meter 20. The first flow meter 19 is used to monitor the inlet water flow, and the second flow meter 20 is used to monitor the internal circulation flow. The supporting pipeline system 8 is equipped with a pressure gauge 21 to monitor the pressure of the open filter electrochemical reaction module 9 during the internal circulation process and backwashing process. The supporting pipeline system 8 is equipped with a first valve 22 and a second valve 23 to control the internal circulation process and backwashing process.

[0041] When the wastewater treatment system is running, the wastewater return flow velocity is set to 0.5–30 m / s. 3 m -2 h -1Simultaneously, with the drain valve 15 and the second valve 23 closed, wastewater enters the electrochemical reaction tank 3 through the inlet 11 located at the bottom of the tank, driven by the wastewater lift pump 2. At the same time, the wastewater return pump 6 and the first valve 22 are activated. The wastewater return pump 6 provides suction to the open-type filtration electrochemical reaction module 9, driving the wastewater to continuously pass through the porous anode 25 and porous cathode 24 into the module. Subsequently, the wastewater returns to the electrochemical reaction tank 3 via the water distributor 10 connected to the reaction module and the internal circulation return port 13, thus achieving an internal circulation process. The wastewater inflow rate can be adjusted by regulating the wastewater lift pump 2, and the mass transfer efficiency of pollutants in the wastewater to the electrode surface reaction area can be adjusted by regulating the wastewater return pump 6. During the operation of the wastewater treatment system, pollutants in the wastewater that can be oxidized, such as organic pollutants, are oxidized or even mineralized in the anode region through direct electron transfer or by the generated hydroxyl radicals; pollutants in the wastewater that can be reduced, such as nitrates and chlorates, can be reduced in the cathode region through direct electron transfer or by the generated atomic hydrogen, and transformed into non-toxic / or low-toxic substances.

[0042] During continuous operation of the reaction system, suspended solids that may be present in the wastewater will be trapped in the electrochemical reaction tank 3 by the porous cathode 24 and porous anode 25. Simultaneously, some smaller suspended solids may clog the porous structures of the porous cathode 24 and porous anode 25, thereby reducing the treatment efficiency of the reaction system. When the pressure gauge 21 detects a 50% increase in the wastewater treatment system pressure, a backwash operation is performed. The backwash operation time is set to 0.5–5 hours, and the backwash flow rate is set to 5–10 times the wastewater return flow rate during system operation. The wastewater treatment system undergoes a backwash process to remove the blockages adhering to the porous structures of the porous cathode 24 and porous anode 25. First, shut down the sewage lift pump 2, DC regulated power supply 4, sewage return pump 6, and first valve 22, and open the drain valve 15 to drain the sewage in the electrochemical reaction tank 3; open the second valve 23, reverse the operation of the sewage return pump 6, and quickly pump the pure water in the backwash tank 7 into the open-type filter electrochemical reaction module 9 through the water distributor 10 connected to the reaction module; then the pure water quickly passes through the microporous structure of the porous anode 25 and the porous cathode 24, and is flushed out along with the blockages in the microporous structure, and finally discharged from the electrochemical reaction tank 3 through the drain port 14.

[0043] The wastewater return pump 6 operates by suction, driving wastewater continuously through the porous anode 25 and porous cathode 24 into the open-type filtration electrochemical reaction module 9. The wastewater then returns to the electrochemical reaction tank 3 via the water distributor 10 connected to the reaction module and the internal circulation return port 13. This operation method effectively traps suspended particulate matter in the wastewater outside the open-type filtration electrochemical reaction module 9, preventing irreversible clogging.

[0044] The wastewater treatment system relies on the porous cathode 24 and porous anode 25 operating in a filtration manner to simultaneously remove pollutants that can be degraded through the electro-oxidation process (such as organic pollutants) and pollutants that can be removed through the electro-reduction process (such as nitrate nitrogen and chlorination disinfection byproducts). Moreover, the internal circulation process accelerates the flow rate of wastewater through the porous electrodes, enhances the mass transfer process of the wastewater treatment system, and ensures the efficient and stable operation of the reactor.

[0045] Example 2: Figure 5 As shown in Comparative Example 1, another embodiment of the present invention is as follows: a wastewater treatment system is used, wherein the open-type filter electrochemical reaction module 9 consists of 3 groups, the porous anode 25 is a Ti / SnO2-Sb electrode with a length of 5cm, a width of 5cm, and a pore size of 10μm, and the porous cathode 24 is a Cu / Cu2O electrode with a length of 5cm, a width of 5cm, and a pore size of 10μm. The distance between the plates of the porous cathode 24 and the porous anode 25 in each module is 1cm, the stacking distance of each module is 1cm, and the volume of the electrochemical reaction tank 3 is 500ml. The treated water sample contains 20μM sulfamethoxazole and 1000μM nitrate nitrogen. During the implementation process, the water sample is pumped at a rate of 50ml / min by the wastewater lift pump 2. ‒1 The flow rate enters the electrochemical reaction tank 3 and is pumped in at 5 m³ / h via a circulating pump. 3 m -2 h -1 The internal circulation flow rate drives the water sample to circulate within the treatment system, with the current density set to 10 mA / cm². ‒2 The result is as follows Figure 5 As shown, the concentration of sulfamethoxazole in the extracted water sample remained stable at around 1.5 μM, with a removal rate of approximately 92.5%, while the concentration of nitrate nitrogen remained stable at around 150 μM, with a removal rate of approximately 75.8%.

[0046] Example 3: Figure 6 As shown in Comparative Example 1, another embodiment of the present invention is as follows: The wastewater treatment system of the present invention is used to treat the biochemical effluent from landfill leachate. The wastewater treatment system comprises six open-type electrochemical reaction modules 9. The porous anode 25 is a Ti / SnO2-Sb electrode with a length of 10cm, a width of 10cm, and a pore size of 15μm. The porous cathode 24 is a Cu / Cu2O-Co electrode with a length of 10cm, a width of 10cm, and a pore size of 15μm. The distance between the electrodes of the porous cathode 24 and the porous anode 25 in each module is 0.5cm, and the stacking distance of each module is 1cm. The volume of the electrochemical reaction tank 3 is 3000ml. The COD concentration of the treated water sample is approximately 350mg / L. ‒1 The nitrate nitrogen concentration is 20 mg / L. ‒1 During the implementation process, the water sample was pumped at a rate of 50 ml / min by the sewage lift pump 2. ‒1The flow rate enters the electrochemical reaction tank 3 and is pumped in at 5 m³ / h via a circulating pump. 3 m -2 h -1 The internal circulation flow rate drives the water sample to undergo an internal circulation process in the treatment system, and the current density is set to 20 mA / cm² based on the surface area of ​​the porous anode 25. ‒2 The result is as follows Figure 6 As shown, the COD concentration of the effluent sample remained stable at 60 mg / L. ‒1 The removal rate was approximately 82.9%, and the NO3-N concentration remained stable at 2.3 mg / L. ‒1 The removal rate was approximately 88.5%. As the treatment process ran continuously for nearly 100 hours, the operating pressure of the treatment system increased by about 40%, and the COD of the effluent sample rose to nearly 100 mg / L. ‒1 The NO3-N concentration increased to 7.5 mg / L. ‒1 Nearby. Suspend the treatment system and drain the wastewater from electrochemical reactor 3 at a rate of 20m³. 3 m -2 h -1 The backwashing process was carried out at a flow rate of [unspecified], lasting for 1 hour. The treatment system was then restarted, and the effluent quality was observed to have almost returned to its original level.

[0047] Example 4: Figures 7 to 8 As shown, a hollow plate 30 is fixedly connected to the bottom surface of the sealing flange 28. Water outlet holes 31 are provided on both sides of the hollow plate 30. A sealing assembly for sealing the water outlet holes 31 is provided inside the hollow plate 30. A circular pipe 32 is connected to the top of the hollow plate 30. A sliding groove 33 is provided inside the circular pipe 32. A connecting pipe 34 is slidably connected within the sliding groove 33. A sealing ring 35 is fixedly connected to the side wall of the connecting pipe 34. A driving assembly for driving the connecting pipe 34 to move upwards is provided inside the hollow plate 30. In this application, when backwashing the porous anode 25 and porous cathode 24, the driving assembly can be used to drive the connecting pipe 34 to move upwards. This allows the connecting pipe 34 to enter the second outlet 29, while the sealing ring 35 seals against the sealing flange 28. When water flows out of the second outlet 29, water enters the hollow plate 30. After the hollow plate 30 is filled with water, the sealing mechanism opens, allowing water to spray evenly from the outlet hole 31, so that the water can evenly rinse the porous anode 25 and porous cathode 24, thereby improving the backwashing effect on the porous anode 25 and porous cathode 24. After backwashing is completed, the connecting pipe 34 is reset by the drive mechanism, and the sealing mechanism seals the outlet hole 31 to prevent impurities in the subsequent sewage from entering the hollow plate 30.

[0048] The driving assembly includes a float 41 slidably connected to the side wall of the hollow plate 30. A connecting plate 40 is fixedly connected to the side wall of the hollow plate 30. A hollow elastic plate 39 is fixedly connected to the top surface of the connecting plate 40. A set of connecting grooves 42 are provided inside the hollow plate 30. One end of the connecting groove 42 communicates with the sliding groove 33, and the other end communicates with the inside of the elastic plate 39. A sealing plate is twisted to the bottom end of the round tube 32 by a torsion spring. A connecting line 36 is fixedly connected between the top surface of the sealing plate and the inner wall of the connecting tube 34. During backwashing, the water in the backwash tank 7 is discharged. At this time, the water level in the open-type filter electrochemical reaction module 9 will drop. The float 41 will move downward and squeeze the elastic plate 39, causing the gas in the elastic plate 39 to escape from the backwash tank 7. When the connecting groove 42 enters the slide 33, the gas pushes the connecting pipe 34 into the second outlet 29, where it is sealed. At the same time, the connecting line 36 pulls the sealing plate, allowing water to smoothly enter the hollow plate 30 from the round pipe 32. After backwashing, when the sewage enters the open-type filter electrochemical reaction module 9, the float 41 rises due to the buoyancy of the water, causing the elastic plate 39 to return to its original position and draw in the gas in the slide 33. At this time, the connecting pipe 34 moves downward, and the sealing plate also resets under the action of the torsion spring to seal the bottom of the round pipe 32, preventing sewage from entering the hollow plate 30. Through the above mechanism, the movement of the connecting pipe 34 and the sealing and opening of the round pipe 32 can be automatically controlled during the backwashing operation.

[0049] The sealing assembly includes a movable plate 37 that is slidably and sealingly connected to the inner wall of the hollow plate 30. The movable plate 37 has a hollow structure and an opening at the top. Both sides of the movable plate 37 are provided with connecting holes 38 corresponding to the water outlet 31. A spring is fixedly connected between the bottom surface of the movable plate 37 and the inner wall of the hollow plate 30. When water is injected into the hollow plate 30, the movable plate 37 will be filled with water. When the hollow plate 30 is also filled with water, water is continued to be injected into the hollow plate 30. At this time, the water will push the movable plate 37 to move downward, so that the connecting hole 38 is aligned with the water outlet 31. At this time, the water can be sprayed out evenly from the water outlet 31 to evenly backwash and unclog the porous anode 25 and the porous cathode 24.

[0050] like Figure 9 As shown, a wastewater treatment method with coupled filtration, electro-oxidation, and electro-reduction functions is disclosed. This method employs the aforementioned wastewater treatment system with coupled filtration, electro-oxidation, and electro-reduction functions, and includes the following steps:

[0051] S1: When the wastewater treatment system is running, the wastewater return flow rate is preset, and at the same time, the drain valve 15 and the second valve 23 are closed. Under the action of the wastewater lift pump 2, the wastewater enters the electrochemical reaction tank 3 through the inlet 11 set at the bottom of the electrochemical reaction tank 3.

[0052] S2: Turn on the sewage return pump 6 and the first valve 22. The sewage return pump 6 provides suction to the open filter electrochemical reaction module 9, driving sewage to continuously pass through the porous anode 25 and the porous cathode 24 into the open filter electrochemical reaction module 9.

[0053] S3: The wastewater then returns to the electrochemical reaction tank 3 via the water distributor 10 and the internal circulation return port 13 of the connected reaction module, realizing the internal circulation process of wastewater. The wastewater inflow rate can be adjusted by regulating the wastewater lift pump 2, and the mass transfer efficiency of pollutants in the wastewater to the electrode surface reaction area can be adjusted by regulating the wastewater return pump 6.

[0054] S4: When the pressure gauge detects a 50% increase in the pressure of the wastewater treatment system, shut down the wastewater lift pump 2 and the DC regulated power supply 4, open the drain valve 15 to drain the wastewater in the electrochemical reaction tank 3; perform a backwashing operation, keep the drain valve 15 open, reverse the wastewater return pump 6, and use the pure water in the backwash tank 7 to rinse the open-type filter electrochemical reaction module 9.

[0055] Working principle: By setting the sewage return flow velocity to 0.5–30 m / s² 3 m -2 h -1 Simultaneously, with the drain valve 15 and the second valve 23 closed, wastewater enters the electrochemical reaction tank 3 through the inlet 11 located at the bottom of the electrochemical reaction tank 3 under the action of the lift pump. At the same time, the wastewater return pump 6 and the first valve 22 are activated. The wastewater return pump 6 provides suction to the open-type filtration electrochemical reaction module 9, driving the wastewater to continuously pass through the porous anode 25 and porous cathode 24 into the open-type filtration electrochemical reaction module 9. Subsequently, the wastewater returns to the electrochemical reaction tank 3 through the water distributor 10 connected to the reaction module and the internal circulation return port 13, realizing the internal circulation process of wastewater. The wastewater inflow rate can be adjusted by regulating the wastewater lift pump 2, and the mass transfer efficiency of pollutants in the wastewater to the electrode surface reaction area can be adjusted by regulating the wastewater return pump 6. During the operation of the wastewater treatment system, pollutants in the wastewater that can be oxidized, such as organic pollutants, are oxidized or even mineralized in the anode region through direct electron transfer or by the generated hydroxyl radicals; pollutants in the wastewater that can be reduced, such as nitrates and chlorates, can be reduced in the cathode region through direct electron transfer or by the generated atomic hydrogen, and transformed into non-toxic / or low-toxic substances.

[0056] During continuous operation of the reaction system, suspended solids that may be present in the wastewater will be trapped in the electrochemical reaction tank 3 by the porous cathode 24 and porous anode 25. Simultaneously, some smaller suspended solids may clog the porous structures of the porous cathode 24 and porous anode 25, thereby reducing the treatment efficiency of the reaction system. When the pressure gauge 21 detects a 50% increase in the wastewater treatment system pressure, a backwash operation is performed. The backwash operation time is set to 0.5–5 hours, and the backwash flow rate is set to 5–10 times the wastewater return flow rate during system operation. The wastewater treatment system undergoes a backwash process to remove the blockages adhering to the porous structures of the porous cathode 24 and porous anode 25. First, shut down the sewage lift pump 2, DC regulated power supply 4, sewage return pump 6, and second valve 22, and open the drain valve 15 to drain the sewage in the electrochemical reaction tank 3; open the second valve 23, reverse the operation of the sewage return pump 6, and quickly pump the pure water in the backwash tank 7 into the open-type filter electrochemical reaction module 9 through the water distributor 10 connected to the reaction module; then the pure water quickly passes through the microporous structure of the porous anode 25 and the porous cathode 24, and is flushed out along with the blockages in the microporous structure, and finally discharged from the electrochemical reaction tank 3 through the drain port 14.

[0057] The wastewater return pump 6 operates by suction, driving wastewater continuously through the porous anode 25 and porous cathode 24 into the open-type filtration electrochemical reaction module 9. The wastewater then returns to the electrochemical reaction tank 3 via the water distributor 10 connected to the reaction module and the internal circulation return port 13. This operation method effectively traps suspended particulate matter in the wastewater outside the open-type filtration electrochemical reaction module 9, preventing irreversible clogging.

[0058] The terms "front," "back," "left," "right," "top," and "bottom" all refer to the figures in the accompanying drawings. Figure 1 Based on the perspective of the observer, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0059] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are 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 limiting the scope of protection of this invention.

[0060] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wastewater treatment system with coupled filtration, electro-oxidation and electro-reduction functions, comprising a raw water tank (1), a sewage lift pump (2), an electrochemical reaction tank (3), a DC regulated power supply (4), a clean water tank (5), a sewage return pump (6), a backwash water tank (7), and a supporting pipeline system (8). Its features are: The electrochemical reaction tank (3) is a rectangular semi-enclosed tank made of non-conductive material. It has multiple stacked open-type filter electrochemical reaction modules (9) and a water distributor (10) connected to the reaction modules. The electrochemical reaction tank (3) is equipped with an inlet (11), a first outlet (12), an internal circulation return port (13), an air outlet (14), and an air outlet valve (15) installed on the air outlet (14). The open-type filter electrochemical reaction module (9) is connected in parallel with the DC regulated power supply (4) by the anode wire (16) and the cathode wire (17); The open-type filter electrochemical reaction module (9) consists of a porous cathode (24) and a porous anode (25) with similar pore sizes, corresponding cathode terminals (26) and anode terminals (27), and a non-conductive sealing flange (28). The sealing flange (28) is provided with a second outlet (29) connected to the water distributor (10). The supporting pipeline system (8) is equipped with a first flow meter (19) and a second flow meter (20). The first flow meter (19) is used to monitor the inlet flow rate, and the second flow meter (20) is used to monitor the internal circulation flow rate. The supporting pipeline system (8) is equipped with a pressure gauge (21) to monitor the pressure of the open filter electrochemical reaction module (9) during the internal circulation process and backwashing process. The supporting pipeline system (8) is equipped with a first valve (22) and a second valve (23) to control the internal circulation process and backwashing process. A hollow plate (30) is fixedly connected to the bottom surface of the sealing flange (28). Water outlet holes (31) are provided on both sides of the hollow plate (30). A sealing component for sealing the water outlet holes (31) is provided inside the hollow plate (30). A round pipe (32) is connected to the top of the hollow plate (30). A sliding groove (33) is provided inside the round pipe (32). A connecting pipe (34) is slidably connected inside the sliding groove (33). A sealing ring (35) is fixedly connected to the side wall of the connecting pipe (34). A driving component for driving the connecting pipe (34) to move upward is provided inside the hollow plate (30). The drive assembly includes a float (41) that is slidably connected to the side wall of the hollow plate (30). A connecting plate (40) is fixedly connected to the side wall of the hollow plate (30). A hollow elastic plate (39) is fixedly connected to the top surface of the connecting plate (40). A set of connecting grooves (42) is provided inside the hollow plate (30). One end of the connecting groove (42) is connected to the sliding groove (33), and the other end is connected to the inside of the elastic plate (39). A sealing plate is twisted to the bottom end of the round tube (32) by a torsion spring. A connecting line (36) is fixedly connected between the top surface of the sealing plate and the inner wall of the connecting tube (34). The sealing assembly includes a movable plate (37) that is slidably connected to the inner wall of the hollow plate (30). The movable plate (37) has a hollow structure inside and an opening at the top. Both sides of the movable plate (37) are provided with connection holes (38) corresponding to the water outlet (31). A spring is fixedly connected between the bottom surface of the movable plate (37) and the inner wall of the hollow plate (30).

2. The wastewater treatment system with coupled filtration, electro-oxidation, and electro-reduction functions according to claim 1, characterized in that: The first outlet (12) is located near the top of the electrochemical reaction tank (3) and above the open filter electrochemical reaction module (9). The internal circulation return port (13) and the drain port (14) are located at the bottom of the electrochemical reaction tank (3).

3. A wastewater treatment method with coupled filtration, electro-oxidation, and electro-reduction functions, wherein the method employs the wastewater treatment system with coupled filtration, electro-oxidation, and electro-reduction functions as described in claim 1, characterized in that: The method includes the following steps: S1: When the wastewater treatment system is running, the wastewater return flow rate is preset, and the drain valve (15) and the second valve (23) are closed. Under the action of the wastewater lift pump (2), the wastewater enters the electrochemical reaction tank (3) through the inlet (11) set at the bottom of the electrochemical reaction tank (3). S2: Turn on the sewage return pump (6) and the first valve (22). The sewage return pump (6) provides suction to the open filter electrochemical reaction module (9), driving sewage to continuously pass through the porous anode (25) and porous cathode (24) into the open filter electrochemical reaction module (9). S3: The wastewater then returns to the electrochemical reaction tank (3) via the water distributor (10) and the internal circulation return port (13) of the connected reaction module, realizing the internal circulation process of wastewater. The wastewater inflow can be adjusted by regulating the wastewater lift pump (2), and the mass transfer efficiency of pollutants in the wastewater to the electrode surface reaction area can be adjusted by regulating the wastewater return pump (6). S4: When the pressure gauge (21) detects that the pressure of the wastewater treatment system has increased by 50%, shut down the sewage lift pump (2) and the DC regulated power supply (4), open the drain valve (15) to drain the sewage in the electrochemical reaction tank (3); perform backwashing operation, keep the drain valve (15) open, reverse the sewage return pump (6), and use the pure water in the backwash tank (7) to rinse the open filter electrochemical reaction module (9).

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