Filtering electrooxidation-electroreduction function coupled wastewater treatment system and method

Abstract

The invention belongs to the technical field of water treatment, and particularly relates to a wastewater treatment system with coupled filtering electrooxidation and electroreduction functions. Comprising a raw water tank, a sewage lifting pump, an electrochemical reaction tank, a direct-current stabilized power supply, a purified water tank, a sewage reflux pump, a backwashing water tank and a matched pipe network system, the electrochemical reaction tank is a cuboid semi-closed tank body made of a non-conductive material, and a plurality of groups of stacked open type filtering electrochemical reaction modules and a water distributor connected with the reaction modules are arranged in the electrochemical reaction tank; a wastewater treatment system is adopted, namely, a porous cathode and a porous anode are simultaneously used as a filtering cathode and a filtering anode respectively, so that the reaction system has diversified treatment capacity, and pollutants capable of being oxidized in sewage are oxidized and removed in a reaction area of the filtering anode; pollutants capable of being reduced in the sewage are reduced and removed in the filtering cathode reaction area.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and specifically relates to a wastewater treatment system and method coupling filtration electro-oxidation and electro-reduction functions. Background Art

[0002] The electrochemical filtration water treatment technology is an advanced oxidation water treatment technology for wastewater treatment. This technology forces wastewater to pass through a porous anode or cathode in a filtration operation mode, strengthening the mass transfer and diffusion process of pollutants in the main wastewater to the electrode interface reaction area, and overcoming the shortcoming of mass transfer limitation in traditional co-current systems. Compared with the traditional co-current electrochemical water treatment system, the filtration electrochemical water treatment system can increase the removal rate of pollutants by several times to dozens of times, thus greatly improving the efficiency and energy efficiency of electrochemical water treatment.

[0003] However, the above technology often has the following defects: The current filtration electrochemical water treatment technology mainly focuses on the treatment of wastewater by a single electrode reaction process, that is, the filtration anodic oxidation process or the filtration cathodic reduction process. A single reaction process usually can only target a single type of pollutant in water. For example, the filtration anodic oxidation process usually can only degrade organic pollutants in water, and the filtration cathodic reduction process can reduce nitrate nitrogen or halogenated disinfection by-products in water. However, the actual wastewater usually has complex water quality and usually contains pollutants such as organic pollutants, ammonia nitrogen, and nitrate nitrogen. Moreover, the current open filtration electrochemical reaction module usually adopts a fully enclosed reactor, that is, the filtration electrode is completely sealed, which not only may exacerbate the irreversible blockage of the filtration electrode material, but also cause waste of the electrode material due to incomplete utilization of the surface reactive area of the filtration electrode material. In addition, during the operation of the filtration electrochemical water treatment system, in order to obtain better effluent water quality, the influent flow rate is usually set small. When the influent flow rate is small, the mass transfer rate of the wastewater treatment system will be greatly reduced, thus weakening the treatment efficiency of the entire wastewater treatment system; although increasing the water flux can improve the mass transfer efficiency, this will lead to a short contact time between the wastewater and the electrode reaction area, and the wastewater reaction is insufficient, resulting in poor effluent water quality. Therefore, the present invention provides a wastewater treatment system and method coupling filtration electro-oxidation and electro-reduction functions. Summary of the Invention

[0004] In order to make up for the deficiencies of the prior art and solve at least one technical problem proposed in the background art.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows: A wastewater treatment system coupling filtration electro-oxidation and electro-reduction functions according to the present invention includes a raw water tank, a sewage lift pump, an electro-chemical reaction tank, a DC regulated power supply, a clean water tank, a sewage reflux pump, a backwash water tank and a supporting pipe network system; the electro-chemical reaction tank is a cuboid semi-closed tank body made of non-conductive material, and is internally provided with multiple groups of stacked open filtration electro-chemical reaction modules and a water distributor connecting the reaction modules. An inlet, a first outlet, an internal circulation return port, an emptying port and an emptying valve provided on the emptying port are arranged on the electro-chemical reaction tank.

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

[0007] Preferably, the first outlet is arranged at a position higher than the open filtration electro-chemical reaction module near the top of the electro-chemical reaction tank, and the first outlet, the internal circulation return port and the emptying port are arranged at the bottom of the electro-chemical reaction tank body.

[0008] Preferably, the open filtration electro-chemical reaction module is composed of a porous cathode and a porous anode with similar pore diameters, corresponding cathode terminals and anode terminals, and a sealing flange made of non-conductive material. A second outlet connected to the water distributor is arranged on the sealing flange.

[0009] Preferably, a first flowmeter and a second flowmeter are arranged on the supporting pipe network system. The first flowmeter is used to monitor the influent flow rate, the second flowmeter is used to monitor the internal circulation flow rate, a pressure gauge is arranged on the supporting pipe network system to monitor the pressure of the open filtration electro-chemical reaction module during the internal circulation process and the backwash process, and a first valve and a second valve are arranged on the supporting pipe network system to control the internal circulation process and the backwash process.

[0010] Preferably, a hollow plate is fixedly connected to the bottom surface of the sealing flange. Water outlet holes are formed on both sides of the hollow plate. A sealing component for sealing the water outlet holes is arranged inside the hollow plate. A round pipe is communicated with the top end of the hollow plate. A sliding groove is formed inside the round pipe. A connecting pipe is hermetically slidably connected inside 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 arranged inside the hollow plate.

[0011] Preferably, the driving component includes a floating block slidably connected to the side wall of the hollow plate. A connecting plate is fixedly connected to the side wall of the hollow plate. The top surface of the connecting plate is fixedly connected with a hollow elastic plate. A group of connecting grooves are formed in the hollow plate. One end of the connecting groove communicates with the sliding groove, and the other end communicates with the inside of the elastic plate. The bottom end of the round tube is torsionally connected with a sealing plate through a torsion spring. A connecting line is fixedly connected between the top surface of the sealing plate and the inner wall of the connecting tube.

[0012] Preferably, the sealing component includes a moving plate hermetically and slidably connected to the inner wall of the hollow plate. The inside of the moving plate is of a hollow structure and is provided with an opening at the top end. Connecting holes corresponding to the water outlet holes are formed on both sides of the moving plate. A spring is fixedly connected between the bottom surface of the moving plate and the inner wall of the hollow plate.

[0013] A wastewater treatment method coupling filtration electro-oxidation and electro-reduction functions. This method uses the above-mentioned wastewater treatment system coupling filtration electro-oxidation and electro-reduction functions. This method includes the following steps:

[0014] S1: When the wastewater treatment system is operating, the reflux flow rate of the sewage is preset in advance. At the same time, the drain valve and the second valve are in the closed state. Under the action of the sewage lift pump, the wastewater enters the electro-chemical reaction tank through the water inlet arranged at the bottom of the electro-chemical reaction tank.

[0015] S2: Open the sewage reflux pump and the first valve. The sewage reflux pump provides suction for the open filtration electro-chemical reaction module, driving the sewage to continuously pass through the porous anode and the porous cathode and enter the open filtration electro-chemical reaction module.

[0016] S3: Then the sewage returns to the electro-chemical reaction tank through the water distributor and the internal circulation return port of the connection reaction module, realizing the internal circulation process of the sewage. By regulating the sewage lift pump, the influent flow rate of the wastewater can be adjusted. By regulating the sewage reflux pump, the mass transfer efficiency of pollutants in the wastewater to the reaction area on the electrode surface can be adjusted.

[0017] S4: When the pressure gauge monitors that the pressure of the wastewater treatment system increases by 50%, turn off the sewage lift pump and the DC regulated power supply, open the drain valve, and drain the sewage in the electro-chemical reaction tank; perform a backwashing operation. Keep the drain valve open, reverse the sewage reflux pump, and use the pure water in the backwashing water tank to wash the open filtration electro-chemical reaction module.

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

[0019] 1. The present invention uses a wastewater treatment system, that is, using a porous cathode and a porous anode as the filtration cathode and the filtration anode respectively, so that the reaction system has diversified treatment capabilities. Pollutants in the sewage that can be oxidized are oxidized and removed in the reaction area of the filtration anode, and pollutants in the sewage that can be reduced are reduced and removed in the reaction area of the filtration cathode.

[0020] 2. Aiming at the problems of insufficient processing capacity at low flow rates and deteriorated effluent quality at high flow rates, the present invention adopts the method of increasing the internal circulation design to ensure that the sewage always passes through the microporous structure of the filter electrode at a high speed, so as to strengthen the mass transfer process of pollutants in the sewage to the electrode surface. The open filter electro-chemical reaction module is stacked in the mode of "cathode - anode - cathode... anode - cathode - anode". This method makes full use of the reactive areas on both sides of the porous cathode and porous anode, and improves the utilization rate of the electrode material.

[0021] 3. Aiming at the problem that the filter electrode in the existing filter-type electro-chemical water treatment system is prone to cause irreversible blockage of the filter electrode pore diameter, the present invention designs an open filter electro-chemical reaction module, that is, the porous anode and the porous cathode are directly in contact with the main sewage, and the sewage is driven to pass through the inside of the open filter electro-chemical reaction module and then flow out by means of suction; during this operation process, suspended solids with larger particle sizes in the sewage can be intercepted in the main sewage to avoid entering the reaction system; at the same time, a backwashing system is designed. When the operating pressure of the reaction system is abnormal, a backwashing operation is carried out to wash away the suspended solids blocking the micropores of the porous anode and the porous cathode. Brief Description of the Drawings

[0022] The present invention will be further described below with reference to the drawings.

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

[0024] Figure 2 is a schematic internal structure diagram of the electro-chemical reaction tank in the present invention;

[0025] Figure 3 is a schematic structural diagram of the open filter electro-chemical reaction module in the present invention;

[0026] Figure 4 is a schematic internal structure diagram of the open filter electro-chemical reaction module in the present invention;

[0027] Figure 5 is a schematic diagram of simultaneously removing sulfamethoxazole and nitrate nitrogen in water by the wastewater treatment system in Example 2 of the present invention;

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

[0029] Figure 7 is a schematic structural diagram of the hollow plate in the open filter electro-chemical reaction module in the present invention;

[0030] Figure 8 is Figure 7 an enlarged view of part A of

[0031] Figure 9 is the method flow chart in the present invention.

[0032] In the figure: 1, raw water tank; 2, sewage lift pump; 3, electro-chemical reaction tank; 4, DC regulated power supply; 5, clean water tank; 6, sewage reflux pump; 7, backwash water tank; 8, supporting pipe network system; 9, open-type filtering electro-chemical reaction module; 10, water distributor; 11, water inlet; 12, first water outlet; 13, internal circulation reflux port; 14, emptying port; 15, emptying valve; 16, anode wire; 17, cathode wire; 18, fixing bracket; 19, first flowmeter; 20, second flowmeter; 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 water outlet; 30, hollow plate; 31, water outlet hole; 32, round pipe; 33, chute; 34, connecting pipe; 35, sealing ring; 36, connecting wire; 37, moving plate; 38, connecting hole; 39, elastic plate; 40, connecting plate; 41, floating block; 42, connecting groove. Specific embodiments

[0033] In order to make the technical means, creative features, achieved purposes and functions of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0034] Embodiment 1: As Figures 1 to 4 shown, a wastewater treatment system with coupled filtering electro-oxidation and electro-reduction functions described in an embodiment of the present invention includes a raw water tank 1, a sewage lift pump 2, an electro-chemical reaction tank 3, a DC regulated power supply 4, a clean water tank 5, a sewage reflux pump 6, a backwash water tank 7 and a supporting pipe network system 8; the electro-chemical reaction tank 3 is a cuboid semi-closed tank body made of non-conductive material, and is internally provided with multiple groups of stacked open-type filtering electro-chemical reaction modules 9 and a water distributor 10 connecting the reaction modules. The electro-chemical reaction tank 3 is provided with a water inlet 11, a first water outlet 12, an internal circulation reflux port 13, an emptying port 14 and an emptying valve 15 arranged on the emptying port 14.

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

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

[0037] The open filtration electrochemical reaction module 9 is composed of a porous cathode 24 and a porous anode 25 with similar pore diameters, corresponding cathode terminals 26 and anode terminals 27, and a sealing flange 28 made of a non-conductive material. A second water outlet 29 connected to the water distributor 10 is arranged on the sealing flange 28; among them, the sealing flange 28 made of a non-conductive material only covers the edge parts of the porous cathode 24 and the porous anode 25, ensuring that most surfaces of the porous cathode 24 and the porous anode 25 can be directly in contact with the main body of sewage. The pore sizes of the filtration anode and the filtration cathode are 0.5 - 100 μm;

[0038] For the same wastewater treatment system, the pore sizes of the porous anode 25 and the porous cathode 24 are kept close to ensure uniform pressure distribution at the contact interfaces between the cathode side and the anode side of the open filtration electrochemical reaction module 9 and the sewage, so as to ensure that the sewage evenly enters the open filtration electrochemical reaction module 9 from the cathode side and the anode side; the plate spacing between the porous anode 25 and the porous cathode 24 in the open filtration electrochemical reaction module 9 is set to 0.5 - 5 cm;

[0039] The material of the porous anode 25 can be an antimony-doped tin dioxide electrode, a lead dioxide electrode, a ruthenium-iridium electrode, a titanium suboxide electrode, and their derivative electrode materials prepared by doping rare earth elements and noble metal elements; the porous cathode 24 can be a metal oxide electrode, a conductive carbon electrode, a titanium suboxide electrode, a noble metal electrode, and their derivative electrode materials prepared by doping rare earth elements and noble metal elements; the input current density of the DC regulated power supply 4 is 1 - 50 mA / cm -2 , and the current density is calculated according to the total area of the porous anode 25 or the porous cathode 24 in the open filtration electrochemical reaction module 9.

[0040] A first flowmeter 19 and a second flowmeter 20 are arranged on the supporting pipe network system 8. The first flowmeter 19 is used to monitor the influent flow rate, and the second flowmeter 20 is used to monitor the internal circulation flow rate. A pressure gauge 21 is arranged on the supporting pipe network system 8 to monitor the pressure of the open filtration electrochemical reaction module 9 during the internal circulation process and the backwashing process. A first valve 22 and a second valve 23 are arranged on the supporting pipe network system 8 to control the internal circulation process and the backwashing process.

[0041] During the operation of the wastewater treatment system, the sewage reflux flow rate is set to 0.5 - 30 m 3 m -2 h -1, while the drain valve 15 and the second valve 23 are in the closed state, the wastewater, under the action of the sewage lift pump 2, enters the electro-chemical reaction tank 3 through the water inlet 11 provided at the bottom of the electro-chemical reaction tank 3; at the same time, the sewage reflux pump 6 and the first valve 22 are opened. The sewage reflux pump 6 provides suction for the open filtration electro-chemical reaction module 9, driving the sewage to continuously pass through the porous anode 25 and the porous cathode 24 and enter the open filtration electro-chemical reaction module 9. Subsequently, the sewage then returns to the electro-chemical reaction tank 3 through the water distributor 10 and the internal circulation return port 13 of the connection reaction module, realizing the internal circulation process of the sewage. By regulating the sewage lift pump 2, the wastewater inlet flow rate can be adjusted, and by regulating the sewage reflux pump 6, the mass transfer efficiency of pollutants in the wastewater to the reaction area on the electrode surface can be adjusted. During the operation of the wastewater treatment system, pollutants in the sewage that can be oxidized, such as organic pollutants, are oxidized or even mineralized through direct electron transfer or oxidation by the generated hydroxyl radicals in the anode region; 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 the action of the generated atomic hydrogen to be converted into non-toxic or low-toxic substances.

[0042] During the continuous operation of the reaction system, suspended solids that may exist in the sewage will be intercepted in the electro-chemical reaction tank 3 by the porous cathode 24 and the porous anode 25. At the same time, some smaller suspended solids may cause blockage of the pore structures of the porous cathode 24 and the porous anode 25, thereby reducing the treatment efficiency of the reaction system. When the pressure gauge 21 monitors that the pressure of the wastewater treatment system increases by 50%, a backwashing operation is carried out. The backwashing operation time is set to 0.5 - 5 h, and the washing flow rate is set to 5 - 10 times the sewage reflux flow rate during system operation. The wastewater treatment system conducts a backwashing process to remove the blockages attached to the pore structures of the porous cathode 24 and the porous anode 25. First, close the sewage lift pump 2, the DC regulated power supply 4, the sewage reflux pump 6, and the first valve 22, and open the drain valve 15 to drain the sewage in the electro-chemical reaction tank 3; open the second valve 23, reverse the sewage reflux pump 6, and quickly pump the pure water in the backwashing water tank 7 into the open filtration electro-chemical reaction module 9 through the water distributor 10 of the connection reaction module; subsequently, the pure water quickly passes through the microporous structures of the filtration porous anode 25 and the filtration porous cathode 24, and along with the blockages in the microporous structures being washed out, finally discharges from the drain port 14 out of the electro-chemical reaction tank 3.

[0043] The sewage reflux pump 6 adopts a suction method, that is, it drives the sewage to continuously pass through the porous anode 25 and the porous cathode 24 and enter the open filtration electro-chemical reaction module 9. Subsequently, the sewage then returns to the electro-chemical reaction tank 3 through the water distributor 10 and the internal circulation return port 13 of the connection reaction module. This operation method can intercept the suspended particulate matter existing in the sewage outside the open filtration electro-chemical reaction module 9 to avoid irreversible blockage of the open filtration electro-chemical reaction module 9.

[0044] The wastewater treatment system relies on the porous cathode 24 and the porous anode 25 in the filtration operation to simultaneously remove pollutants in water that can be degraded through the electro-oxidation process (such as organic pollutants) and pollutants removed through the electro-reduction process (such as nitrate nitrogen and chlorinated disinfection by-products). Moreover, relying on the internal circulation process, the flow rate of the wastewater passing through the porous electrodes is accelerated, the mass transfer process of the wastewater treatment system is strengthened, and the efficient and stable operation of the reactor is ensured.

[0045] Example 2: As Figure 5 shown, compared with Example 1, another implementation manner of the present invention is as follows: The wastewater treatment system is adopted, in which there are 3 groups of open filtration electro-chemical reaction modules 9. The porous anode 25 is a Ti / SnO2-Sb electrode with a length of 5 cm, a width of 5 cm, and a pore diameter of 10 μm. The porous cathode 24 is a Cu / Cu2O electrode with a length of 5 cm, a width of 5 cm, and a pore diameter of 10 μm. The plate spacing between the porous cathode 24 and the porous anode 25 in each module is 1 cm, the stack distance of each module is 1 cm, and the volume of the electro-chemical reaction tank 3 is 500 ml. The treated water sample contains 20 μM sulfamethoxazole and 1000 μM nitrate nitrogen. During the implementation process, the water sample enters the electro-chemical reaction tank 3 at a flow rate of 50 ml / min under the action of the sewage lift pump 2, and is driven by the internal circulation flow rate of 5 m -1 m 3 m -2 h -1 to perform the internal circulation process in the treatment system, and the current density is set to 10 mA / cm -2 . The results are as Figure 5 shown. The concentration of sulfamethoxazole in the effluent water sample is stable at about 1.5 μM, and the removal rate is about 92.5%. The concentration of nitrate nitrogen is stable at about 150 μM, and the removal rate is about 75.8%.

[0046] Example 3: As Figure 6 shown, compared with Example 1, another implementation manner of the present invention is as follows: The biochemical effluent of landfill leachate is treated by the wastewater treatment system of the present invention. The wastewater treatment system is carried out, in which there are 6 groups of open filtration electro-chemical reaction modules 9. The porous anode 25 is a Ti / SnO2-Sb electrode with a length of 10 cm, a width of 10 cm, and a pore diameter of 15 μm. The porous cathode 24 is a Cu / Cu2O-Co electrode with a length of 10 cm, a width of 10 cm, and a pore diameter of 15 μm. The plate spacing between the porous cathode 24 and the porous anode 25 in each module is 0.5 cm, the stack distance of each module is 1 cm, and the volume of the electro-chemical reaction tank 3 is 3000 ml. The original COD concentration of the treated water sample is about 350 mg / L -1 , and the nitrate nitrogen concentration is 20 mg / L -1 . During the implementation process, the water sample enters the electro-chemical reaction tank 3 at a flow rate of 50 ml / min under the action of the sewage lift pump 2, and at -1The flow enters the electrochemical reaction tank 3 and circulates at a rate of 5 m 3 m -2 h -1 The internal circulation flow rate drives the water sample to perform an internal circulation process in the treatment system. The current density is set to 20 mA / cm² according to the surface area of the porous anode 25 -2 . The results are as Figure 6 shown. The COD concentration of the effluent water sample is stable at about 60 mg / L -1 , and the removal rate is about 82.9%. The NO₃⁻-N concentration is stable at about 2.3 mg / L -1 . As the continuous operation of the treatment process approaches 100 h, the operating pressure of the treatment system increases by about 40%. At the same time, the COD of the effluent water sample increases to nearly 100 mg / L -1 , and the NO₃⁻-N concentration increases to around 7.5 mg / L -1 . Pause the treatment system, drain the sewage inside the electrochemical reaction tank 3, and perform a backwashing process at a flow rate of 20 m 3 m -2 h -1 . The whole process lasts for 1 h. Then restart the treatment system, and it is observed that the effluent water quality almost returns to the original level.

[0047] Example 4: As Figures 7 to 8 shown, a hollow plate 30 is fixedly connected to the bottom surface of the sealing flange 28. Water outlet holes 31 are opened on both sides of the hollow plate 30. A sealing assembly for sealing the water outlet holes 31 is arranged inside the hollow plate 30. A round pipe 32 is communicated with the top end of the hollow plate 30. A sliding groove 33 is opened inside the round pipe 32. A connecting pipe 34 is hermetically 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 assembly for driving the connecting pipe 34 to move upward is arranged inside the hollow plate 30; in the present application, when backwashing the porous anode 25 and the porous cathode 24, the driving assembly can be used to drive the connecting pipe 34 to move upward, so that the connecting pipe 34 enters the second water outlet 29. At the same time, the sealing ring 35 will fit and seal with the sealing flange 28. At this time, when water comes out from the second water outlet 29, the water will enter the hollow plate 30. After the hollow plate 30 is filled with water, the sealing mechanism is opened, so that the water is evenly sprayed out from the water outlet holes 31, so that the water can evenly wash the porous anode 25 and the porous cathode 24, so as to improve the dredging effect of backwashing the porous anode 25 and the porous cathode 24. After the backwashing is completed, the driving mechanism is used to reset the connecting pipe 34, and at the same time, the sealing mechanism seals the water outlet holes 31 to prevent impurities in the subsequent sewage from entering the hollow plate 30.

[0048] The driving component includes a floating block 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. The top surface of the connecting plate 40 is fixedly connected to a hollow elastic plate 39. A group of connecting grooves 42 are formed in 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. The bottom end of the circular tube 32 is torsionally connected with a sealing plate through a torsion spring. A connecting wire 36 is fixedly connected between the top surface of the sealing plate and the inner wall of the connecting tube 34; when the present application performs backwashing, the water in the backwashing water tank 7 will be discharged. At this time, the water level in the open-type filtration electro-chemical reaction module 9 will drop. At this time, the floating block 41 will move downward and squeeze the elastic plate 39, so that the gas in the elastic plate 39 enters the sliding groove 33 through the connecting groove 42. At this time, the gas will push the connecting tube 34 into the second water outlet 29 and be hermetically connected to the second water outlet 29. At the same time, the connecting wire 36 will pull the sealing plate, so that water can smoothly enter the hollow plate 30 from the circular tube 32. After the backwashing is completed, when the sewage enters the open-type filtration electro-chemical reaction module 9, the floating block 41 will rise due to the buoyancy of the water, so that the elastic plate 39 will recover and suck the gas in the sliding groove 33. At this time, the connecting tube 34 will move downward, and at the same time, the sealing plate will also reset under the action of the torsion spring to seal the bottom end of the circular tube 32 to prevent sewage from entering the hollow plate 30. Through the above mechanism, the movement of the connecting tube 34 can be automatically controlled during the backwashing operation, as well as the sealing and opening of the circular tube 32.

[0049] The sealing component includes a moving plate 37 hermetically and slidably connected to the inner wall of the hollow plate 30. The inside of the moving plate 37 is a hollow structure and the top end is open. Connecting holes 38 corresponding to the water outlet holes 31 are formed on both sides of the moving plate 37. A spring is fixedly connected between the bottom surface of the moving plate 37 and the inner wall of the hollow plate 30; when the water in the present application is injected into the hollow plate 30, the water will fill the inside of the moving plate 37. When the water in the hollow plate 30 is also full, continue to inject water into the hollow plate 30. At this time, the water will push the moving plate 37 downward, so that the connecting holes 38 are aligned with the water outlet holes 31. At this time, the water can be evenly sprayed out from the water outlet holes 31 to evenly backwash and dredge the porous anode 25 and the porous cathode 24.

[0050] As Figure 9 shown, a wastewater treatment method coupling filtration electro-oxidation and electro-reduction functions uses the above-mentioned wastewater treatment system coupling filtration electro-oxidation and electro-reduction functions. The method includes the following steps:

[0051] S1: When the wastewater treatment system is in operation, preset the sewage reflux flow rate. At the same time, the drain valve 15 and the second valve 23 are in the closed state. Under the action of the sewage lift pump 2, the wastewater enters the electrochemical reaction tank 3 through the water inlet 11 provided at the bottom of the electrochemical reaction tank 3;

[0052] S2: Open the sewage reflux pump 6 and the first valve 22. The sewage reflux pump 6 provides suction for the open filtration electrochemical reaction module 9, driving the sewage to continuously pass through the porous anode 25 and the porous cathode 24 and enter the open filtration electrochemical reaction module 9;

[0053] S3: Subsequently, the sewage returns to the electrochemical reaction tank 3 through the water distributor 10 and the internal circulation return port 13 of the connection reaction module, realizing the internal circulation process of the sewage. By regulating the sewage lift pump 2, the wastewater inlet flow rate can be adjusted, and by regulating the sewage reflux pump 6, the mass transfer efficiency of pollutants in the wastewater to the reaction area on the electrode surface can be adjusted;

[0054] S4: When the pressure gauge monitors that the pressure of the wastewater treatment system has increased by 50%, turn off the sewage lift pump 2 and the DC regulated power supply 4, open the drain valve 15, and drain the sewage in the electrochemical reaction tank 3; perform a backwashing operation. Keep the drain valve 15 open, reverse the sewage reflux pump 6, and use the pure water in the backwashing water tank 7 to wash the open filtration electrochemical reaction module 9.

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

[0056] During the continuous operation of the reaction system, suspended solids that may be present in the sewage will be intercepted by the porous cathode 24 and the porous anode 25 in the electrochemical reaction tank 3. At the same time, some smaller suspended solids may cause blockage of the pore structures of the porous cathode 24 and the porous anode 25, thereby reducing the treatment efficiency of the reaction system. When the pressure gauge 21 monitors that the pressure of the wastewater treatment system increases by 50%, a backwashing operation is carried out. The backwashing operation time is set to 0.5 - 5h, and the washing flow rate is set to 5 - 10 times the sewage reflux flow rate during system operation. The wastewater treatment system undergoes a backwashing process to remove the blockages attached to the pore structures of the porous cathode 24 and the porous anode 25. First, close the sewage lift pump 2, the DC regulated power supply 4, the sewage reflux pump 6, and the second valve 22, and open the drain valve 15 to drain the sewage in the electrochemical reaction tank 3; open the second valve 23 and reverse the sewage reflux pump 6 to quickly pump the pure water in the backwashing water tank 7 into the open filtration electrochemical reaction module 9 through the water distributor 10 connecting the reaction module; then the pure water quickly passes through the microporous structures of the filtration porous anode 25 and the filtration porous cathode 24, and along with the blockages in the microporous structures being washed out, it finally discharges from the drain port 14 out of the electrochemical reaction tank 3.

[0057] The sewage reflux pump 6 adopts a suction method, that is, it drives the sewage to continuously pass through the porous anode 25 and the porous cathode 24 into the open filtration electrochemical reaction module 9, and then the sewage then returns to the electrochemical reaction tank 3 through the water distributor 10 connecting the reaction module and the internal circulation reflux port 13. This operation method can intercept the suspended particulate matter present in the sewage outside the open filtration electrochemical reaction module 9 to avoid irreversible blockage of the open filtration electrochemical reaction module 9.

[0058] The above front, back, left, right, up, and down are all based on Figure 1 the description in the attached drawings of the specification. According to the standard of the observer's perspective, the side of the device facing the observer is defined as the front, and the left side of the observer is defined as the left, and so on.

[0059] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the protection scope of the present 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 by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A wastewater treatment system integrating filtration, electro-oxidation and electro-reduction functions, comprising a raw water tank (1), a sewage lift pump (2), an electro-chemical reaction tank (3), a DC regulated power supply (4), a clean water tank (5), a sewage reflux pump (6), a backwash water tank (7) and a supporting pipe network system (8); It is characterized in that: The electro-chemical reaction tank (3) is a cuboid semi-closed tank made of non-conductive material, and is internally provided with multiple groups of stacked open-type filtration electro-chemical reaction modules (9) and a water distributor (10) connecting the reaction modules. An inlet (11), a first outlet (12), an internal circulation return port (13), an emptying port (14) and an emptying valve (15) arranged on the emptying port (14) are arranged on the electro-chemical reaction tank (3).

2. The wastewater treatment system with the coupling of filtration electro-oxidation and electro-reduction functions according to claim 1, characterized in that: The open-type filtration electro-chemical reaction module (9) is connected in parallel with the DC regulated power supply (4) through an anode wire (16) and a cathode wire (17).

3. A wastewater treatment system coupling filtration, electro-oxidation, and electro-reduction functions according to claim 2, characterized in that: The first outlet (12) is arranged at a position close to the top of the electro-chemical reaction tank (3) and higher than the open-type filtration electro-chemical reaction module (9), and the internal circulation return port (13) and the emptying port (14) are arranged at the bottom of the electro-chemical reaction tank (3).

4. A wastewater treatment system coupling filtration, electro-oxidation and electro-reduction functions according to claim 3, characterized in that: The open-type filtration electro-chemical reaction module (9) consists of a porous cathode (24) and a porous anode (25) with similar pore diameters, corresponding cathode terminals (26) and anode terminals (27), and a non-conductive sealing flange (28). A second outlet (29) connected to the water distributor (10) is arranged on the sealing flange (28).

5. A wastewater treatment system coupling filtration electro-oxidation and electro-reduction functions according to claim 4, characterized in that: A first flowmeter (19) and a second flowmeter (20) are arranged on the supporting pipe network system (8). The first flowmeter (19) is used to monitor the influent flow rate, and the second flowmeter (20) is used to monitor the internal circulation flow rate. A pressure gauge (21) is arranged on the supporting pipe network system (8) to monitor the pressure of the open-type filtration electro-chemical reaction module (9) during the internal circulation process and the backwash process. A first valve (22) and a second valve (23) are arranged on the supporting pipe network system (8) to control the internal circulation process and the backwash process.

6. The wastewater treatment system coupling filtration, electrooxidation and electroreduction functions according to claim 5, characterized in that: A hollow plate (30) is fixedly connected to the bottom surface of the sealing flange (28). Water outlet holes (31) are formed on both sides of the hollow plate (30). A sealing assembly for sealing the water outlet holes (31) is arranged inside the hollow plate (30). A round pipe (32) is communicated with the top end of the hollow plate (30). A sliding groove (33) is formed inside the round pipe (32). A connecting pipe (34) is hermetically 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 assembly for driving the connecting pipe (34) to move upward is arranged inside the hollow plate (30).

7. A wastewater treatment system coupling filtration, electro-oxidation, and electro-reduction functions according to claim 6, characterized in that: The driving component includes a floating block (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). The top surface of the connecting plate (40) is fixedly connected with a hollow elastic plate (39). A group of connecting grooves (42) are formed in 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). The bottom end of the circular tube (32) is torsionally connected with a sealing plate through a torsion spring. A connecting wire (36) is fixedly connected between the top surface of the sealing plate and the inner wall of the connecting pipe (34).

8. A wastewater treatment system coupling filtration, electro-oxidation, and electro-reduction functions according to claim 7, characterized in that: The sealing component includes a moving plate (37) hermetically and slidably connected to the inner wall of the hollow plate (30). The inside of the moving plate (37) is of a hollow structure and is open at the top end. Connecting holes (38) corresponding to the water outlet holes (31) are formed on both sides of the moving plate (37). A spring is fixedly connected between the bottom surface of the moving plate (37) and the inner wall of the hollow plate (30).

9. A wastewater treatment method coupling filtration electro-oxidation and electro-reduction functions, which uses the wastewater treatment system coupling filtration electro-oxidation and electro-reduction functions described in claim 8, and is characterized in that: The method comprises the following steps: S1: When the wastewater treatment system is operating, the flow rate of the sewage reflux is preset. At the same time, the drain valve (15) and the second valve (23) are in the closed state. Under the action of the sewage lift pump (2), the wastewater enters the electro-chemical reaction tank (3) through the water inlet (11) arranged at the bottom of the electro-chemical reaction tank (3). S2: The sewage reflux pump (6) and the first valve (22) are opened. The sewage reflux pump (6) provides suction for the open filtration electro-chemical reaction module (9), driving the sewage to continuously pass through the porous anode (25) and the porous cathode (24) and enter the open filtration electro-chemical reaction module (9). S3: Subsequently, the sewage returns to the electro-chemical reaction tank (3) through the water distributor (10) and the internal circulation return port (13) of the connection reaction module, realizing the internal circulation process of the sewage. The influent flow rate of the wastewater can be adjusted by controlling the sewage lift pump (2), and the mass transfer efficiency of the pollutants in the wastewater to the reaction area on the electrode surface can be adjusted by controlling the sewage reflux pump (6). S4: When the pressure gauge (21) monitors that the pressure of the wastewater treatment system increases by 50%, the sewage lift pump (2) and the DC regulated power supply (4) are turned off, and the drain valve (15) is opened to drain the sewage in the electro-chemical reaction tank (3). A backwashing operation is carried out. The drain valve (15) remains open, and the sewage reflux pump (6) is reversed to use the pure water in the backwashing water tank (7) to wash the open filtration electro-chemical reaction module (9).

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