Water treatment device for hydrogen production by electrolysis of effluent from a sewage plant

Abstract

The application discloses a water treatment device for hydrogen production by electrolysis of effluent of a sewage plant, comprising a device main body, a filtering assembly and a sedimentation mechanism, wherein the device main body comprises an outer shell, a partition plate and a pump body, the partition plate is fixed in the outer shell to divide the inner cavity of the outer shell into an upper containing cavity and a lower containing cavity, a first installation hole is formed in the partition plate, and a first control valve is arranged in the first installation hole; and the sedimentation mechanism is arranged in the lower containing cavity. The application has the beneficial effects that: through the alkaline condition in the alkaline electrolysis process, the alkaline electrolyte is mixed with tail water in advance, the metal cations in the tail water are precipitated in advance and removed through membrane filtration, the mixed liquid is then introduced into an electrolytic tank, impurities are efficiently and economically removed, the expensive reverse osmosis device is not needed, the amount of the precipitate in the electrolytic tank is reduced, and the catalytic activity and stability of the electrode are improved.

Description

Technical Field

[0001] This invention relates to the field of water treatment equipment technology, and specifically to a water treatment device for producing hydrogen by electrolysis of wastewater from sewage treatment plants. Background Technology

[0002] Hydrogen energy, as a clean and efficient energy carrier, is a key component of my country's energy system and a core direction for the development of strategic emerging industries. Currently, over 90% of hydrogen comes from fossil fuels such as coal and natural gas, whose high energy consumption and carbon emissions limit its widespread application in low-carbon sectors. In contrast, green hydrogen production can achieve true zero-carbon hydrogen production through electrolysis or photocatalytic water splitting using fluctuating renewable energy sources such as wind and solar power.

[0003] However, the process of producing hydrogen through water electrolysis requires a large amount of energy and high-quality water. In regions rich in clean energy, high-quality water is often scarce, creating a conflict between energy and water resources. It is worth noting that low-grade water (such as seawater, surface water, groundwater, and wastewater effluent) accounts for 97% of global water resources. If low-grade water could be directly used for hydrogen electrolysis, it would not only avoid the large consumption of purified water in traditional processes but also eliminate the need for water purification facilities. This would significantly reduce investment and operating costs for water treatment-related infrastructure, thereby resolving the fundamental conflict between energy and water resources and enabling hydrogen production across the entire region.

[0004] Seawater, with its extremely high salinity (10-30 times higher than other water sources), is not advantageous. Although surface water and groundwater have similar quality to wastewater treatment plant effluent, their quality fluctuates significantly due to geological changes and seasonal factors, and these sources prioritize meeting the water needs of municipal residents, agriculture, and industry. In contrast, wastewater treatment plant effluent offers advantages in both quality and quantity stability, making it an ideal choice for hydrogen production from low-grade water. More importantly, the pure oxygen produced during water electrolysis can be used as a high-quality oxygen source for biological treatment processes in wastewater treatment plants, helping to improve aeration efficiency and reduce energy consumption. Furthermore, wastewater treatment plants typically have large land areas and minimal shading, making them suitable for installing photovoltaic systems to provide efficient energy supply for electrolysis equipment.

[0005] In a water electrolysis hydrogen production system, raw water enters the electrolysis cycle after the addition of electrolyte. As hydrogen and oxygen are generated, the electrolyte gradually concentrates. When the liquid level reaches a predetermined level, raw water needs to be added to maintain normal system operation. However, the concentration of the electrolyte causes trace impurities in the water to gradually accumulate. During electrolysis, a large amount of OH- is generated at the cathode due to the hydrogen evolution reaction. - This causes a localized increase in pH near the cathode, and the abundant Ca in the effluent... 2+ Mg 2+This will cause Mg(OH)₂ and Ca(OH)₂ to precipitate and adhere to the cathode catalyst surface, hindering the exposure of active sites and thus reducing the catalytic activity and stability of the electrode; trace amounts of Fe in the tailwater 2+ Cu 2+ It may trigger the Fenton reaction, generating hydroxyl radicals that attack the membrane and electrode catalytic materials, thereby damaging the membrane and catalytic layer.

[0006] Currently, the main electrolyte for advanced wastewater treatment in wastewater treatment plants is reverse osmosis, but its high investment and operating costs, as well as membrane fouling issues, make it difficult to widely apply in industry. Another technology is ion adsorption, but high concentrations of OH... - This affects its use and may even cause it to quickly become saturated with adsorption.

[0007] In traditional alkaline electrolysis, because the electrolyte is usually a high concentration of KOH, precipitation easily occurs rapidly when the wastewater comes into contact with the electrolyte. Simultaneously, the recycling process leads to electrolyte concentration, which also triggers precipitation. This type of precipitation hinders the exposure of active sites, thereby reducing the catalytic activity and stability of the electrode. Summary of the Invention

[0008] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a water treatment device for hydrogen production by electrolysis of wastewater effluent from sewage treatment plants. This device solves the technical problem in the prior art where precipitation easily occurs rapidly when effluent comes into contact with electrolyte, hindering the exposure of active sites and thus reducing the catalytic activity and stability of the electrode.

[0009] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: This invention provides a water treatment device for producing hydrogen through electrolysis of wastewater from a sewage treatment plant, comprising: The device body includes an outer shell, a partition, and a pump body. The partition is fixed inside the outer shell to divide the inner cavity of the outer shell into an upper receiving cavity and a lower receiving cavity. A first mounting hole is provided on the partition, and a first control valve is provided in the first mounting hole. An inlet and an outlet communicating with the lower receiving cavity are provided on the outer shell. The inlet and the outlet are respectively used to communicate with the two ends of the electrolytic cell. The two ends of the pump body are respectively connected to the lower receiving cavity and the first mounting hole. The filter assembly includes a first filter element and a second filter element sequentially disposed along the height direction within the upper receiving cavity; and, A settling mechanism is disposed within the lower receiving cavity.

[0010] In some embodiments, the outer casing includes a lower casing, an upper casing, and a top cover. The lower casing is detachably connected to one end of the upper casing, and the top cover is detachably connected to the other end of the upper casing. The partition is fixed inside the lower casing, the first filter element is disposed inside the upper casing, and the second filter element is disposed inside the lower casing.

[0011] In some embodiments, the upper housing is provided with a first pressurization port and a tailwater inlet. The first pressurization port is provided with a first pressurization valve and is used to communicate with the outlet of the air injection pressurization device. The tailwater inlet is provided with a tailwater inlet valve and is used to supply wastewater effluent from the wastewater treatment plant.

[0012] In some embodiments, the lower housing is provided with a dosing port and a dosing valve, and the dosing port is used to add a complexing agent; the lower housing is also provided with a second pressurizing port and a second pressurizing valve, and the second pressurizing port is used to communicate with the outlet of the gas injection pressurization device.

[0013] In some embodiments, the first filter element includes a first support and a plurality of first filter membranes. The first support is fixed inside the upper housing. The first support has a plurality of first fixing holes, and each of the first filter membranes is installed in a corresponding first fixing hole.

[0014] In some embodiments, the second filter element includes a second support and a plurality of second filter membranes. The second support is fixed inside the lower housing and has a plurality of second fixing holes. Each of the second filter membranes is installed in a corresponding second fixing hole.

[0015] In some embodiments, the settling mechanism includes a baffle and several inclined plates. The baffle is fixed to the lower end of the partition and is inclined. The height of the lower end of the baffle is higher than the height of the liquid inlet. A left chamber and a right chamber are formed on both sides of the baffle. The left chamber is connected to the liquid outlet, and the upper side of the right chamber is connected to the first mounting hole. Each of the inclined plates is equally spaced, inclined, and parallel to the left chamber.

[0016] In some embodiments, the settling mechanism further includes a horizontal plate, which is fixed between the baffle and the lower housing. A second mounting hole is provided on the horizontal plate, and a second control valve is provided in the second mounting hole. The two ends of the pump body are respectively connected to the first mounting hole and the second mounting hole.

[0017] In some embodiments, an inlet valve is provided on the inlet and an outlet valve is provided on the outlet.

[0018] The present invention also provides a water treatment method for producing hydrogen by electrolysis of wastewater effluent, applicable to the aforementioned water treatment device for producing hydrogen by electrolysis of wastewater effluent, and comprising the following steps: S1. After one round of electrolysis is completed, close the first control valve, and then pass the alkaline electrolyte in the electrolytic cell into the lower containment cavity through the inlet. After the alkaline electrolyte flows through the sedimentation mechanism, it is discharged back to the electrolytic cell from the outlet to form a cycle. During this process, the sedimentation mechanism can remove the precipitate in the alkaline electrolyte. S2. After the precipitate in the alkaline electrolyte is completely removed, open the first control valve and the pump body to pump the alkaline electrolyte from the lower chamber into the upper chamber. Then close the first control valve and let the tailwater flow into the upper chamber. After passing through the first filter element, the tailwater is thoroughly mixed with the alkaline electrolyte, which can remove the Ca from the tailwater. 2+ Mg 2+ Mn 2+ The reaction produces Ca(OH)₂, Mg(OH)₂ and Mn(OH)₂ precipitates; S3. Open the first control valve and reverse the pump body. Under the drive of the pump body, the new electrolyte passes through the second filter and enters the lower containment chamber. Then close the first control valve and introduce the new electrolyte into the electrolytic cell to prepare for the next round of electrolytic hydrogen production.

[0019] Compared with existing technologies, the water treatment device for hydrogen production by electrolysis of wastewater effluent provided by this invention has the following advantages: By utilizing the inherent alkaline conditions during alkaline electrolysis, the alkaline electrolyte is mixed with the effluent in advance, causing the metal cations in the effluent to precipitate in advance and be removed by membrane filtration. The mixture is then passed into the electrolytic cell, thereby efficiently and economically removing impurities without relying on expensive reverse osmosis devices and reducing the amount of precipitate generated in the electrolytic cell. At the same time, the sedimentation mechanism can effectively remove the precipitates generated during alkaline electrolysis, ensuring the exposure of active sites and thus improving the catalytic activity and stability of the electrodes. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a water treatment device for producing hydrogen by electrolysis of wastewater from a sewage treatment plant, provided in an embodiment of the present invention. Figure 2 yes Figure 1 A schematic diagram of the water treatment device in the diagram; Figure 3 yes Figure 1 A three-dimensional structural diagram of the outer shell; Figure 4 yes Figure 1 A cross-sectional structural diagram of the water treatment device in the diagram; Explanation of reference numerals in the attached drawings: 1-Main body of the device, 11-Outer shell, 111-Lower shell, 1111-Inlet, 1112-Outlet, 1113-Dosing port, 1114-Dosing valve, 1115-Drain outlet, 1116-Inlet valve, 1117-Outlet valve, 1118-Second pressurization port, 1119-Second pressurization valve, 112-Upper shell, 1121-First pressurization port, 1122-Tailwater inlet, 1123-First pressurization valve, 1124-Tailwater inlet valve, 1 13-Top cover, 12-Baffle, 121-First control valve, 13-Pump body, 2-Filter assembly, 21-First filter element, 211-First bracket, 2111-First fixing hole, 212-First filter membrane, 22-Second filter element, 221-Second bracket, 2211-Second fixing hole, 222-Second filter membrane, 3-Sedimentation mechanism, 31-Baffle, 32-Inclined plate, 33-Horizontal plate, 331-Second control valve, 4-Electrolytic cell, 5-Circulating pump, 6-Heater. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] To address the technical problem in existing technologies where effluent and electrolyte readily generate precipitation, hindering the exposure of active sites and thus reducing the catalytic activity and stability of the electrode, this invention provides a water treatment device for hydrogen production by electrolysis of wastewater from wastewater treatment plants. This device reduces the amount of precipitation generated in the electrolyzer, ensures the exposure of active sites, and thereby improves the catalytic activity and stability of the electrode.

[0023] Please see Figures 1-4 , Figure 1 This is a schematic diagram of a water treatment device for producing hydrogen by electrolysis of wastewater effluent in an embodiment of the present invention. The water treatment device for producing hydrogen by electrolysis of wastewater effluent includes a main body 1, a filter assembly 2, and a sedimentation mechanism 3.

[0024] The main body 1 of the device includes a shell 11, a partition 12, and a pump body 13. The partition 12 is fixed inside the shell 11 to divide the inner cavity of the shell 11 into an upper receiving cavity and a lower receiving cavity. A first mounting hole is provided on the partition 12, and a first control valve 121 is provided in the first mounting hole. The shell 11 has an inlet 1111 and an outlet 1112 that communicate with the lower receiving cavity. The inlet 1111 and the outlet 1112 are used to communicate with the two ends of the electrolytic cell 4, respectively. The two ends of the pump body 13 are respectively connected to the lower receiving cavity and the first mounting hole. In this embodiment, the pump body 13 needs to meet the requirements for normal use in a strongly alkaline environment, and also needs to be able to rotate in both directions, so that it can pump the alkaline electrolyte upward into the upper receiving cavity to react with the tail water, and can also discharge the reacted electrolyte downward into the lower receiving cavity and finally enter the electrolytic cell.

[0025] The filter assembly 2 includes a first filter element 21 and a second filter element 22 arranged sequentially along the height direction within the upper receiving cavity.

[0026] The settling mechanism 3 is located inside the lower receiving cavity.

[0027] Working process: After one round of electrolysis is completed, the first control valve 121 and the second control valve 331 remain closed. The flow rate of the circulating pump 5 is reduced, and the alkaline electrolyte in the electrolytic cell 4 is introduced into the lower containment chamber through the inlet 1111. After passing through the settling mechanism 3, the alkaline electrolyte is discharged back into the electrolytic cell 4 from the outlet 1112, forming a circulation. During this process, the slow circulation speed causes the settling mechanism 3 to accumulate the precipitate produced by the concentration of the alkaline electrolyte, which is eventually discharged from the drain outlet 1115. After the precipitate in the alkaline electrolyte is completely removed, the first control valve 121 and the pump body 13 are opened. The alkaline electrolyte in the lower containment chamber is pumped into the upper containment chamber through the pump body 13. Then the first control valve 121 is closed, and the tailwater (i.e., the effluent from the sewage treatment plant) is introduced into the upper containment chamber. After passing through the first filter element 21, the tailwater is fully mixed with the alkaline electrolyte, which can remove the Ca in the tailwater. 2+ Mg 2+ Mn 2+ Heavy metals react to form Ca(OH)2, Mg(OH)2, and Mn(OH)2 precipitates; the first filter element 21 can remove the original precipitates in the tailwater; the first control valve 121 is opened, and the pump body 13 is turned on in reverse. The new electrolyte (i.e., the liquid after the tailwater and the electrolyte are mixed) is driven by the pump body 13, passes through the second filter element 22 and enters the lower containment chamber. Then the first control valve 121 is closed, and the new electrolyte is introduced into the electrolytic cell 4 to prepare for the next round of electrolytic hydrogen production. The precipitates generated by the reaction of tailwater and alkaline electrolyte are blocked on the second filter element 22.

[0028] The technical solution provided by this invention utilizes the inherent alkaline conditions of alkaline electrolysis to pre-mix the alkaline electrolyte with the tailwater, causing the metal cations in the tailwater to precipitate in advance and be removed by membrane filtration. The mixture is then passed into the electrolytic cell, thereby efficiently and economically removing impurities without relying on expensive reverse osmosis devices and reducing the amount of precipitation generated in the electrolytic cell. At the same time, the sedimentation mechanism can effectively remove the precipitation generated during alkaline electrolysis, ensuring the exposure of active sites and thus improving the catalytic activity and stability of the electrodes in the electrolytic cell.

[0029] It should be noted that the existing alkaline electrolyte circulation system also includes a circulation pump 5 and a heater 6. The inlet of the circulation pump 5 is connected to one end of the electrolytic cell 4, the outlet of the circulation pump 5 is connected to the liquid inlet 1111, one end of the heater 6 is connected to the other end of the electrolytic cell 4, and the other end of the heater 6 is connected to the liquid outlet 1112.

[0030] In one embodiment, please refer to Figures 2-4 The outer shell 11 includes a lower shell 111, an upper shell 112, and an upper cover 113. The lower shell 111 is detachably connected to one end of the upper shell 112, and the upper cover 113 is detachably connected to the other end of the upper shell 112. The partition 12 is fixed inside the lower shell 111. The first filter element 21 is disposed inside the upper shell 112, and the second filter element 22 is disposed inside the lower shell 111.

[0031] In one embodiment, please refer to Figures 2-4 The upper housing 112 is provided with a first pressurization port 1121 and a tailwater inlet 1122. The first pressurization port 1121 is provided with a first pressurization valve 1123. The first pressurization port 1121 is used to connect with the outlet of the air injection pressurization device, so as to accommodate the internal pressurization upward and promote the mixed liquid to pass through the first filter element 21. The tailwater inlet 1122 is provided with a tailwater inlet valve 1124. The tailwater inlet 1122 is used to supply the sewage treatment plant effluent (i.e. tailwater) into the inlet.

[0032] In one embodiment, please refer to Figures 2-4 The lower housing 111 has a dosing port 1113, and a dosing valve 1114 is provided on the dosing port 1113. The dosing port 1113 is used to add a complexing agent. In this embodiment, the complexing agent is an EDTA complexing agent, used to remove residual Ca from the alkaline solution. 2+ .

[0033] In one embodiment, please refer to Figures 2-4The first filter element 21 includes a first support 211 and a plurality of first filter membranes 212. The first support 211 is fixed inside the upper housing 112, and a plurality of first fixing holes 2111 are provided on the first support 211. Each of the first filter membranes 212 is respectively installed in the corresponding first fixing hole 2111. In this embodiment, the first filter membrane 212 can be a microfiltration membrane or an ultrafiltration membrane. If the effluent passes smoothly, the air injection and pressurization device does not need to be activated. Otherwise, the upper cover 113 needs to be sealed and the air injection and pressurization device activated. When the first filter membrane 212 is severely contaminated, it can be replaced by opening the upper cover 113.

[0034] In one embodiment, please refer to Figures 2-4 The second filter element 22 includes a second support 221 and a plurality of second filter membranes 222. The second support 221 is fixed inside the lower housing 111, and a plurality of second fixing holes 2211 are provided on the second support 221. Each of the second filter membranes 222 is respectively installed in the corresponding second fixing hole 2211. In this embodiment, the second filter membrane 222 can be a microfiltration membrane or an ultrafiltration membrane. If the effluent passes smoothly, the air injection and pressurization device does not need to be activated. Otherwise, the upper cover 113 needs to be sealed, and the air injection and pressurization device needs to be activated. When the second filter membrane 222 is severely polluted, the second filter element 22 can be exposed by disassembling the upper housing 112 and a new membrane can be replaced.

[0035] In one embodiment, please refer to Figures 2-4 The settling mechanism 3 includes a baffle 31 and several inclined plates 32. The baffle 31 is fixed to the lower end of the partition 12. The baffle 31 is inclined, and its lower end is higher than the height of the inlet 1111. A left chamber and a right chamber are formed on both sides of the baffle 31, respectively. The left chamber is connected to the outlet 1112, and the upper side of the right chamber is connected to the first mounting hole. Each of the inclined plates 32 is evenly spaced, inclined, and parallel to the left chamber. In use, electrolyzed water slowly flows upward through the gaps between the inclined plates 32 to the outlet 1112. During this process, the sediment in the electrolyzed water will descend along the inclined plates 32 until it settles at the bottom of the lower shell 111. A drain port 1115 is provided at the bottom of the lower shell 111, and a drain valve is provided on the drain port 1115. By periodically opening the drain valve, the sediment accumulated in the drain port 1115 can be cleaned.

[0036] In one embodiment, please refer to Figures 2-4 The settling mechanism 3 also includes a horizontal plate 33, which is fixed between the baffle 31 and the lower housing 111. A second mounting hole is provided on the horizontal plate 33, and a second control valve 331 is provided in the second mounting hole. The two ends of the pump body 13 are respectively connected to the first mounting hole and the second mounting hole.

[0037] In one embodiment, please refer to Figures 2-4 The inlet 1111 is provided with an inlet valve 1116, and the outlet 1112 is provided with an outlet valve 1117.

[0038] In one embodiment, please refer to Figures 2-4 The lower housing 111 is also provided with a second pressurization port 1118, and a second pressurization valve 1119 is provided on the second pressurization port 1118. The second pressurization port 1118 is used to connect with the outlet of the gas injection pressurization device, so that it can accommodate the internal pressurization downward and promote the mixed liquid to pass through the second filter element 22.

[0039] The present invention also provides a water treatment method for producing hydrogen by electrolysis of wastewater effluent, applicable to the aforementioned water treatment device for producing hydrogen by electrolysis of wastewater effluent, and comprising the following steps: S1. After one round of electrolysis is completed, the first control valve 121 and the second control valve 331 remain closed. The flow rate of the circulation pump 5 is reduced, and the alkaline electrolyte in the electrolytic cell 4 is introduced into the lower containment cavity through the inlet 1111. After the alkaline electrolyte flows through the sedimentation mechanism 3, it is discharged back to the electrolytic cell 4 from the outlet 1112, forming a circulation. During this process, the slow circulation flow rate causes the sedimentation mechanism 3 to accumulate the precipitate generated by the concentration in the alkaline electrolyte, and finally discharge it from the drain outlet 1115. S2. After the precipitate in the alkaline electrolyte is completely removed, the first control valve 121, the second control valve 331, and the pump body 13 are opened. The alkaline electrolyte in the lower chamber is pumped into the upper chamber through the pump body 13. At this time, the liquid level of the alkaline electrolyte in the upper chamber is at level B. Then, the first control valve 121 and the second control valve 331 are closed. Next, the inlet valve 1116 is opened to introduce a certain amount of effluent (i.e., sewage treatment plant effluent) into the upper chamber. Then, the inlet valve 1116 is closed. After the effluent passes through the first filter element 21, it is fully mixed with the alkaline electrolyte. At this time, the liquid level reaches level C, which allows the Ca in the effluent to be removed. 2+ Mg 2+ Mn 2+ The reaction produces Ca(OH)₂, Mg(OH)₂, and Mn(OH)₂ precipitates; then, the dosing valve 1114 is opened to introduce a complexing agent into the upward-facing cavity to remove residual Ca from the alkali solution. 2+ It should be noted that, since Ca(OH)₂ is slightly soluble in water, simply reacting it with an alkaline electrolyte cannot remove the Ca in the wastewater. 2+ Complete removal; therefore, in this invention, residual Ca in the alkaline solution is removed by introducing a complexing agent into the upward-facing cavity. 2+ It can completely remove Ca. 2+ ; S3. Open the first control valve 121 and the second control valve 331, and open the pump body 13 in reverse. The new electrolyte (i.e., the liquid after the tail water and the electrolyte are mixed) is driven by the pump body 13, passes through the second filter element 22 and enters the lower containment chamber. At this time, the liquid level reaches the liquid level A. Close the first control valve 121 and the second control valve 331, and then pass the new electrolyte into the electrolytic cell 4 through the circulation pump 5 to prepare for the next round of electrolytic hydrogen production. The precipitate produced by the reaction of tail water and alkaline electrolyte is blocked on the second filter element 22.

[0040] The beneficial effects of the technical solution provided by this invention include: (1) By taking advantage of the alkaline conditions inherent in the alkaline electrolysis process, the alkaline electrolyte is mixed with the tail water in advance, which promotes the precipitation of metal cations in the tail water and removes them through membrane filtration. The mixture is then passed into the electrolytic cell, thereby efficiently and economically removing impurities without relying on expensive reverse osmosis devices and reducing the amount of precipitation generated in the electrolytic cell. (2) The sedimentation mechanism can effectively remove the precipitates generated during alkaline electrolysis, ensuring the exposure of active sites, thereby improving the catalytic activity and stability of the electrodes in the electrolytic cell; (3) A removable membrane is installed. When membrane fouling leads to a decrease in filtration efficiency, it can be repaired by disassembling the water tank and replacing the membrane with a new one. (4) A membrane support is provided to accommodate different types of membranes to achieve electrolyte clarification, including microfiltration and ultrafiltration. An additional top pressurization device can be provided to ensure the normal operation of the ultrafiltration system.

[0041] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A water treatment method for producing hydrogen from wastewater effluent by electrolysis, applicable to a water treatment device for producing hydrogen from wastewater effluent by electrolysis, the water treatment device comprising a main body, a filter assembly, and a sedimentation mechanism; the main body comprising a shell, a partition, and a pump body; the partition fixed within the shell to divide the inner cavity of the shell into an upper cavity and a lower cavity; a first mounting hole provided on the partition, a first control valve disposed within the first mounting hole; an inlet and an outlet communicating with the lower cavity provided on the shell, the inlet and outlet being respectively connected to both ends of an electrolytic cell; both ends of the pump body being respectively connected to the lower cavity and the first mounting hole; the filter assembly comprising a first filter element and a second filter element sequentially disposed along the height direction within the upper cavity; the sedimentation mechanism disposed within the lower cavity; The outer shell includes a lower shell, an upper shell, and a top cover. The lower shell is detachably connected to one end of the upper shell, and the top cover is detachably connected to the other end of the upper shell. The partition is fixed inside the lower shell. The first filter element is disposed inside the upper shell, and the second filter element is disposed inside the lower shell. The settling mechanism includes a baffle and several inclined plates. The baffle is fixed to the lower end of the partition and is inclined. The height of the lower end of the baffle is higher than the height of the liquid inlet. A left chamber and a right chamber are formed on both sides of the baffle. The left chamber is connected to the liquid outlet, and the upper side of the right chamber is connected to the first mounting hole. Each of the inclined plates is equally spaced, inclined and parallel to the left chamber. The settling mechanism also includes a horizontal plate, which is fixed between the baffle and the lower housing. A second mounting hole is provided on the horizontal plate, and a second control valve is provided in the second mounting hole. The two ends of the pump body are respectively connected to the first mounting hole and the second mounting hole. Its features are, The method includes the following steps: S1. After one round of electrolysis is completed, the first control valve and the second control valve remain closed. The flow rate of the circulation pump is reduced, and the alkaline electrolyte in the electrolytic cell is introduced into the lower containment chamber through the inlet. After the alkaline electrolyte flows through the sedimentation mechanism, it is discharged back to the electrolytic cell from the outlet, forming a circulation. During this process, the slow circulation flow rate causes the sedimentation mechanism to accumulate the precipitate generated by the concentration of the alkaline electrolyte, which is eventually discharged from the drain outlet. S2. After the precipitate in the alkaline electrolyte is completely removed, open the first control valve, the second control valve, and the pump body. The pump body pumps the alkaline electrolyte from the lower chamber into the upper chamber. Then close the first and second control valves. Next, open the tailwater inlet valve to allow a certain amount of tailwater to flow into the upper chamber. Then close the tailwater inlet valve. After passing through the first filter element, the tailwater is thoroughly mixed with the alkaline electrolyte, allowing the Ca in the tailwater to be removed. 2+ Mg 2+ Mn 2+ The reaction produces Ca(OH)₂, Mg(OH)₂, and Mn(OH)₂ precipitates; then the dosing valve is opened, and a complexing agent is introduced into the upward-facing chamber to remove residual Ca from the alkali solution. 2+ ; S3. Open the first control valve and the second control valve, and open the pump body in reverse. The new electrolyte, driven by the pump body, passes through the second filter and enters the lower containment chamber. Close the first control valve and the second control valve, and then pass the new electrolyte into the electrolytic cell through the circulation pump to prepare for the next round of electrolytic hydrogen production. The precipitate produced by the reaction of the tail water and the alkaline electrolyte is blocked on the second filter.

2. The water treatment method for producing hydrogen through electrolysis of wastewater from a sewage treatment plant according to claim 1, characterized in that, The upper housing is provided with a first pressurization port and a tailwater inlet. The first pressurization port is provided with a first pressurization valve and is used to connect with the outlet of the air injection pressurization device. The tailwater inlet is provided with a tailwater inlet valve and is used to supply wastewater effluent from the wastewater treatment plant.

3. The water treatment method for producing hydrogen through electrolysis of wastewater from a sewage treatment plant according to claim 1, characterized in that, The lower housing is provided with a drug inlet and a drug inlet valve, which is used to add a complexing agent; the lower housing is also provided with a second pressurization port and a second pressurization valve, which is used to connect to the outlet of the gas injection pressurization device.

4. The water treatment method for producing hydrogen through electrolysis of wastewater from a sewage treatment plant according to claim 1, characterized in that, The first filter element includes a first support and a plurality of first filter membranes. The first support is fixed inside the upper housing. The first support has a plurality of first fixing holes, and each of the first filter membranes is installed in the corresponding first fixing hole.

5. The water treatment method for producing hydrogen through electrolysis of wastewater from a sewage treatment plant according to claim 1, characterized in that, The second filter element includes a second support and a plurality of second filter membranes. The second support is fixed inside the lower housing. The second support has a plurality of second fixing holes, and each of the second filter membranes is installed in the corresponding second fixing hole.

6. The water treatment method for producing hydrogen through electrolysis of wastewater from a sewage treatment plant according to claim 1, characterized in that, The inlet is equipped with an inlet valve, and the outlet is equipped with an outlet valve.

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