Defluorination device for water treatment

Abstract

The invention discloses a water treatment defluorination device which consists of a nano bubble generator, a spiral pipeline mixer and a tubular membrane and is used for efficiently removing fluorine-containing wastewater. After the wastewater passes through the nano bubble generator to generate nano bubbles, the nano bubbles are fully mixed and reacted with the defluorination agent added by the dosing pipe in the spiral pipeline mixer to form floc precipitates. Then, the wastewater enters a tubular membrane for cross-flow filtration, a concentrated solution returns to the mixer through a return pipe, and purified water is discharged from a filtered water outlet. The tubular membrane adopts a multi-layer silicon carbide filtering structure, and is high in filtering precision and resistant to chemical corrosion. The device is provided with a circulating pump, a backwashing system and automatic valve control, so that online cleaning and automatic operation can be realized. The inner wall of the membrane can be automatically cleaned through buoyancy and gravity, and the service life of the membrane is prolonged. The device is high in integration level, small in occupied area, low in reagent dosage, suitable for defluorination treatment of industrial wastewater, capable of being installed in a skid-mounted or fixed mode and easy and convenient to operate and maintain.

Description

Technical Field

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

[0002] With the tightening of environmental protection policies, both nationally and locally, requirements for the treatment of fluoride-containing wastewater are becoming increasingly stringent. Resins, reverse osmosis, and other methods can effectively remove fluoride from water, but the cost of the treatment process is very high, with water treatment costs generally exceeding 3 yuan per ton. Because the chemical method for treating fluoride-containing wastewater is effective and more economical, it has been accepted by a large number of corporate customers. However, during the chemical defluoridation process, the precipitate generated is too light to settle easily. To ensure that the fluoride content in the effluent meets the standard, a large amount of chemical must be added, and sufficient sedimentation time is required. Therefore, at this stage, chemical defluoridation still has problems such as large space required for process equipment, large amounts of chemical addition, and high operating costs. These problems have also seriously restricted the development of enterprises.

[0003] For example, the Chinese patent announcement number CN221166360U, the announcement date is June 18, 2024, and the application name is wastewater defluoridation device. The application discloses a wastewater defluoridation device, which realizes fluoride ion treatment by setting up a first dosing tank, an inclined tube sedimentation tank, a second dosing tank, a flocculation sedimentation tank, a filter press system, an electric flocculation module and other structures. Although it can achieve good fluoride removal effect, it still has the problems of large process equipment footprint, large amount of reagent addition and high operating cost. Summary of the Invention

[0004] The present invention overcomes the problems of large space required for process equipment, large amounts of reagents added, and high operating costs in the prior art of treating fluorine-containing wastewater using a chemical method. The present invention provides a water treatment and defluorination device that can separate the suspension formed after adding the chemical through nanobubbles and tubular membrane filtration. Only defluorination chemicals are required, and no additional flocculants are needed, thereby reducing the amount of chemicals used. The pore size of the tubular membrane is between 0.05 and 0.2 μm, and the membrane material is mainly silicon carbide, which can effectively reduce the adhesion of aluminum-based chemicals and achieve physical and chemical separation of high-concentration precipitated flocs from water. A spiral pipe mixer is used to replace the original sedimentation tank, and cross-flow filtration is performed in conjunction with the tubular membrane to achieve enrichment of the precipitated flocs, improve the overall defluorination efficiency of the defluorination chemical, and solve the problems of large space required for existing equipment, large amounts of reagents added, and high operating costs.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: a water treatment and defluorination device, comprising: A nano bubble generator is provided with a first water inlet, an air inlet and a first water outlet; A spiral pipe mixer is provided with a second water inlet and a second water outlet, the first water outlet and the second water inlet are connected through a first pipe; The tubular membrane is provided with a third water inlet, a third water outlet and a filtered water outlet; the second water outlet is connected to the third water inlet through a second pipe; the third water outlet is connected to the first pipe through a return pipe; A dosing pipe communicated with the first pipe.

[0006] Fluoride-containing wastewater enters the nanobubble generator through the first water inlet. Air entering through the inlet uses the shear force of the nanobubble generator to form nanoscale bubbles in the water, which then flows out of the first water outlet. The defluoridation agent enters the first pipe through the dosing pipe and enters the spiral pipe mixer together with the fluoride-containing wastewater carrying a large number of nanoscale bubbles. The spiral pipe mixer is equipped with a spiral liner and a mixing pipe. The local vortex formed by the spiral liner promotes a full reaction between the defluoridation agent and fluoride ions to form flocculent precipitation. The wastewater then passes through the second pipe at the second water outlet and enters the tubular membrane at the third water inlet. The solid and liquid in the wastewater are separated through cross-flow filtration of the tubular membrane. The concentrated liquid returns to the spiral pipe mixer through the reflux pipe, and the filtered water flows out of the filter outlet.

[0007] Therefore, the present invention uses nanobubbles and tubular membrane filtration to separate the solid-liquid suspension formed after drug addition. This method requires only a defluorination agent, eliminating the need for additional flocculants, thereby reducing the amount of agent used. By replacing the existing sedimentation tank with a spiral pipe mixer and combining it with tubular membranes for cross-flow filtration, the system enriches the precipitated flocs and improves the overall defluorination efficiency of the defluorination agent, effectively addressing the issues of existing equipment, such as large footprint, high agent dosage, and high operating costs.

[0008] Preferably, a circulation pump and a circulation valve are provided on the second pipeline.

[0009] The circulation pump can deliver the wastewater in the spiral pipe mixer to the tubular membrane, providing pressure for the tubular membrane separation. The circulation valve can control the flow of the second pipe. When the tubular membrane needs to be backwashed, the circulation valve can be closed to prevent the spiral pipe mixer from being affected by the backwashing of the tubular membrane.

[0010] Preferably, a reflux valve is provided on the reflux pipe.

[0011] The reflux valve can control the flow and closing of the reflux pipe.

[0012] Preferably, the air inlet is connected to an air pump.

[0013] The air pump can deliver air into the nano bubble generator, so that the nano bubble generator can generate bubbles smoothly.

[0014] Preferably, the filter outlet is connected to the outlet pipe, an outlet valve is provided on the outlet pipe, a backwash pipe connected to the outlet pipe is also provided between the outlet valve and the filter outlet, and a backwash valve is provided on the backwash pipe; a bottom discharge pipe is provided at the bottom of the tubular membrane, and a bottom discharge valve is provided on the bottom discharge pipe.

[0015] After the equipment has been running for a certain period of time, the impurities filtered out will affect the flow rate of the tubular membrane, so a backwash pipe is installed. When the tubular membrane needs to be backwashed, the reflux valve, circulation valve, and outlet valve can be closed, and the backwash valve and bottom drain valve can be opened. Clean water flows from the backwash pipe into the outlet pipe, then enters the tubular membrane from the outlet pipe, backwashing the tubular membrane, discharging impurities from the third water inlet, and finally flowing out from the bottom drain valve.

[0016] Preferably, the tubular membrane comprises a tubular membrane housing and a tubular membrane column arranged in the tubular membrane housing, and the tubular membrane column comprises a plurality of silicon carbide layers with gradually decreasing particle sizes from the inside to the outside.

[0017] Silicon carbide material is used to gradually filter the wastewater, achieving better filtering effects.

[0018] Preferably, the tubular membrane column comprises a first silicon carbide layer with a particle size of less than 0.5 μm, a second silicon carbide layer with a particle size of less than 0.2 μm, and a third silicon carbide layer with a particle size of less than 0.05 μm from the inside to the outside. The three layers of silicon carbide are sintered three times at a temperature above 1500℃ to reorganize and bond the three types of particles. The tubular membrane has excellent chemical resistance.

[0019] Preferably, a cleaning piece is provided in the tubular membrane column, and the cleaning piece includes a cleaning head arranged above and a sinking head arranged below the cleaning head; the cleaning head includes a cleaning sleeve and a plurality of cleaning strips arranged outside the cleaning sleeve; the cleaning sleeve is provided with an upper floating cavity; when the tubular membrane is filled with wastewater, the buoyancy of the cleaning sleeve drives the cleaning piece to move upward to the top of the tubular membrane column; after the wastewater in the tubular membrane is discharged from the bottom, the cleaning piece moves downward under the action of gravity, and the cleaning strips clean the inner wall of the tubular membrane column.

[0020] When treating wastewater, the tubular membrane column is filled with wastewater, and the cleaning head is affected by buoyancy, driving the entire cleaning part to move upward, with the cleaning head located at the top of the cleaning part. When the tubular membrane needs to be backwashed, the wastewater in the tubular membrane column is discharged due to the opening of the bottom discharge valve. At this time, the cleaning part moves downward along the inner wall of the tubular membrane column under the action of gravity. During the movement, the cleaning strip can contact the inner wall of the tubular membrane column and clean the impurities attached to the inner wall of the tubular membrane column. Therefore, each time backwashing is performed, the cleaning part used in this application can clean the inner wall of the tubular membrane column, thereby improving the cleaning effect of the inner wall of the tubular membrane column.

[0021] Preferably, an elastic scraping ring is provided on the outer circumference of the top of the cleaning head, and the elastic scraping ring is in contact with the inner wall of the tubular membrane column.

[0022] When the cleaning strip moves on the inner wall of the tubular membrane column, it can clean the impurities attached to the inner wall of the tubular membrane column, thereby reducing the adhesion of impurities to the inner wall of the tubular membrane. Finally, under the action of the elastic scraper ring, the impurities on the inner wall of the tubular membrane column are cleaned.

[0023] Preferably, a shrink sleeve is provided on the top of the inner side wall of the cleaning sleeve, and the diameter of the shrink sleeve gradually decreases toward the direction of the sinking head.

[0024] A reflow groove is formed between the outer periphery of the shrink sleeve and the inner wall of the cleaning sleeve. This allows a portion of the water flowing through the shrink sleeve to flow into the reflow groove, which acts as a barrier to the water flow. Therefore, during wastewater treatment, the impact of the wastewater on the reflow groove can be used to transport the cleaning element to the top of the tubular membrane column, allowing the cleaning element to clean the inner wall of the tubular membrane column during the next backwash.

[0025] Compared with existing technologies, the present invention offers the following advantages: It uses nanobubbles and tubular membrane filtration to separate the solid-liquid suspension formed after drug addition, requiring only defluorination agents and no additional flocculants, thereby reducing the amount of agents used. By replacing the existing sedimentation tank with a spiral pipe mixer and combining it with tubular membranes for cross-flow filtration, it enriches the precipitated flocs and improves the overall defluorination efficiency of the defluorination agent, effectively addressing the issues of existing equipment, such as large footprint, high agent dosage, and high operating costs.

[0026] A backwash pipe is set up. When the tubular membrane needs to be backwashed, the reflux valve, circulation valve and outlet valve can be closed, and the backwash valve and bottom drain valve can be opened. Clean water flows from the backwash pipe into the outlet pipe, and then enters the tubular membrane from the outlet pipe to backwash the tubular membrane. Impurities are discharged from the third water inlet and finally flow out from the bottom drain valve. The whole process does not require chemical cleaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention.

[0028] Figure 2 It is a three-dimensional structural diagram of the tubular membrane housing of the present invention.

[0029] Figure 3 It is a three-dimensional structural diagram of the tubular membrane column of the present invention.

[0030] Figure 4 is a cross-sectional view of the tubular membrane column of the present invention.

[0031] Figure 5 This is a cross-sectional view of a tubular membrane column in Example 3 of the present invention.

[0032] Figure 6 yes Figure 5 A partial enlarged view of the .

[0033] Figure 7 It is a three-dimensional structural diagram of the cleaning component of the present invention.

[0034] In the figure: 1, nano bubble generator, 11, first water inlet, 12, first water outlet, 13, air inlet; 2. spiral pipe mixer, 21. second water inlet, 22. second water outlet; 3. Tubular membrane, 31. Third water inlet, 32. Third water outlet, 33. Filter outlet, 34. Tubular membrane housing, 35. Tubular membrane column, 351. First silicon carbide layer, 352. Second silicon carbide layer, 353. Third silicon carbide layer, 36. Outer annular cavity, 37. Inner cavity; 4. Dosing pipe, 401. Dosing valve, 41. First pipeline, 42. Second pipeline, 421. Circulation pump, 422. Circulation valve, 43. Return pipe, 431. Return valve, 44. Water inlet pipe, 441. Water inlet valve, 45. Water outlet pipe, 451. Water outlet valve, 46. Flushing pipe, 461. Backwash valve, 47. Bottom drain pipe, 471. Bottom drain valve; 5. Air pump; 6. Cleaning part, 61. Cleaning head, 611. Cleaning sleeve, 612. Cleaning strip, 613. Upper floating chamber, 614. Elastic scraper ring, 615. Shrink sleeve, 616. Reflux groove, 62. Sinking head, 63. Connecting rod. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings: Example 1: Reference Figures 1 to 4 As shown, a water treatment and defluorination device comprises: The nano bubble generator 1 is provided with a first water inlet 11, an air inlet 13 and a first water outlet 12; The spiral pipe mixer 2 is provided with a second water inlet 21 and a second water outlet 22, and the first water outlet 12 is connected to the second water inlet 21 through a first pipe 41; The tubular membrane 3 is provided with a third water inlet 31, a third water outlet 32 and a filtered water outlet 33; the second water outlet 22 is connected to the third water inlet 31 through a second pipe 42; the third water outlet 32 is connected to the first pipe 41 through a return pipe 43; The dosing pipe 4 is connected to the first pipeline 41. The dosing pipe 4 is provided with a dosing valve 401 for controlling the connection or closing of the dosing pipe 4.

[0036] The third water inlet 31 is provided at the bottom of the tubular membrane 3, the third water outlet 32 is provided at the top of the tubular membrane 3, and the filtered water outlet 33 is provided on the sidewall of the top of the tubular membrane 3. The third water inlet 31 is provided at the bottom of the tubular membrane 3 so that during the water treatment process, the bottom of the tubular membrane 3 can be filled with wastewater from bottom to top, allowing the wastewater to fully fill the tubular membrane 3, thereby maximizing the efficiency of the tubular membrane 3 in filtering water.

[0037] The first water inlet 11 is connected to a water inlet pipe 44 , and a water inlet valve 441 is provided on the water inlet pipe 44 for controlling the connection and closing of the water inlet pipe 44 .

[0038] Fluorine-containing wastewater enters the nanobubble generator 1 through the first water inlet 11. Air entering through the air inlet 13 forms nanoscale bubbles in the water due to the shear force in the nanobubble generator 1. The bubbles then flow out of the first water outlet 12. The defluoridation agent enters the first pipe 41 through the dosing pipe 4 and, together with the fluoride-containing wastewater carrying a large number of nanoscale bubbles, enters the spiral pipe mixer 2. The spiral pipe mixer 2 is equipped with a spiral liner and a mixing pipe. The local vortex formed by the spiral liner promotes a full reaction between the defluoridation agent and fluoride ions to form flocculent precipitation. The wastewater then flows through the second pipe 42 from the second water outlet 22 and enters the tubular membrane 3 from the third water inlet 31. The solid and liquid in the wastewater are separated by cross-flow filtration through the tubular membrane 3. The concentrated liquid flows back into the spiral pipe mixer 2 through the reflux pipe 43, and the filtered water flows out through the filtered water outlet 33.

[0039] Nanobubbles and tubular membrane 3 filtration separate the suspension formed after drug addition into solids and liquids, requiring only defluorination agents and no additional flocculants, thus reducing the amount of agents used. The spiral pipe mixer 2 replaces the existing sedimentation tank, and combined with tubular membrane 3 for cross-flow filtration, enriches the precipitated flocs and improves the overall defluorination efficiency of the defluorination agent, effectively solving the problems of existing equipment with large footprints, high agent dosage, and high operating costs.

[0040] In one embodiment, a circulation pump 421 and a circulation valve 422 are provided on the second pipe 42. The circulation pump 421 can deliver wastewater from the spiral pipe mixer 2 to the tubular membrane 3, providing pressure for separation by the tubular membrane 3. The circulation valve 422 can control the flow of water in the second pipe 42. When the tubular membrane 3 needs to be backwashed, the circulation valve 422 can be closed to prevent the backwashing of the tubular membrane 3 from affecting the spiral pipe mixer 2.

[0041] In one embodiment, a reflux valve 431 is provided on the reflux pipe 43. The reflux valve 431 can control the flow and closing of the reflux pipe 43.

[0042] The air inlet 13 is connected to the air pump 5. The air pump 5 can send air into the nano bubble generator 1, so that the nano bubble generator 1 can smoothly generate bubbles.

[0043] In one embodiment, the tubular membrane 3 includes a tubular membrane housing 34 and a tubular membrane column 35 disposed in the tubular membrane housing 34 . The tubular membrane column 35 includes a plurality of silicon carbide layers with gradually decreasing particle sizes from the inside to the outside.

[0044] The tubular membrane column 35 and the tubular membrane housing 34 cooperate to form an outer annular cavity 36, which is connected to the filtered water outlet 33. The tubular membrane column 35 is centrally opened, forming an inner cavity 37 at its center. Wastewater passes through the inner cavity 37, is filtered through the tubular membrane column 35, and then enters the outer annular cavity 36, ultimately flowing out of the filtered water outlet 33.

[0045] The tubular membrane column 35 comprises, from the inside out, a first silicon carbide layer 351 with particles less than 0.5 μm in size, a second silicon carbide layer 352 with particles less than 0.2 μm in size, and a third silicon carbide layer 353 with particles less than 0.05 μm in size. The use of three different silicon carbide particle sizes allows for progressive filtration of wastewater, resulting in enhanced filtration effectiveness. The three layers of silicon carbide are sintered at temperatures exceeding 1500°C in three steps to restructure and bond the three types of particles, giving the tubular membrane 3 excellent chemical resistance.

[0046] In one embodiment, the filtered water outlet 33 is connected to a water outlet pipe 45, which is provided with a water outlet valve 451 for controlling its connection and closure. A backwash pipe 46 is provided between the water outlet valve 451 and the filtered water outlet 33, connected to the water outlet pipe 45. A backwash valve 461 is provided on the backwash pipe 46. A bottom drain pipe 47 is provided at the bottom of the tubular membrane 3, and a bottom drain valve 471 is provided on the bottom drain pipe 47. The second pipe 42 is connected to the bottom drain pipe 47 between the bottom drain valve 471 and the third water inlet 31.

[0047] The working principle of this application is as follows: the water inlet valve 441, the dosing valve 401, the backflow valve 431, the circulation valve 422, and the water outlet valve 451 are opened, and the remaining valves are closed. Fluorine-containing wastewater enters the nanobubble generator 1 through the first water inlet 11. The air pump 5 sends air into the nanobubble generator 1 through the air inlet 13. The shear force in the nanobubble generator 1 forms nanoscale bubbles in the water, which then flows out from the first water outlet 12. The defluoridation agent enters the first pipe 41 from the dosing pipe 4 and enters the spiral pipe mixer 2 together with the fluoride-containing wastewater carrying a large number of nanoscale bubbles. The spiral pipe mixer 2 is provided with a spiral liner and a mixing pipe. The local vortex formed by the spiral liner promotes the defluoridation agent to fully react with fluoride ions to form flocculent precipitation; the wastewater then passes through the second pipe 42 from the second water outlet 22 and enters the tubular membrane 3 from the third water inlet 31. The solid and liquid in the wastewater are separated by cross-flow filtration through the tubular membrane 3, and the concentrated liquid is returned to the spiral pipe mixer 2 through the reflux pipe 43. The filtered water flows out from the filter outlet 33 and finally flows out from the outlet pipe 45.

[0048] After the equipment has been running for a certain period of time, the filtered impurities will affect the membrane flux of the tubular membrane 3. Therefore, a backwash pipe 46 is provided. When the tubular membrane 3 needs to be backwashed, the reflux valve 431, circulation valve 422, and outlet valve 451 can be closed, and the backwash valve 461 and bottom drain valve 471 can be opened. Clean water flows from the backwash pipe 46 into the outlet pipe 45, then enters the tubular membrane 3 from the outlet pipe 45, backwashing the tubular membrane 3, discharging impurities from the third water inlet 31, and finally flowing out of the bottom drain valve 471.

[0049] Therefore, this application can be used in conjunction with an automatic control program to control the opening and closing of each valve, automatically switching between the treatment of fluorine-containing wastewater and the backwashing of the tubular membrane 3. The overall equipment can be a civil structure or a skid-mounted equipment, which is easy to move and assemble. It adopts remote control or automatic control, and does not require on-site personnel management.

[0050] Example 2: Reference Figures 1 to 7 As shown, a water treatment and defluorination device comprises: The nano bubble generator 1 is provided with a first water inlet 11, an air inlet 13 and a first water outlet 12; The spiral pipe mixer 2 is provided with a second water inlet 21 and a second water outlet 22, and the first water outlet 12 is connected to the second water inlet 21 through a first pipe 41; The tubular membrane 3 is provided with a third water inlet 31, a third water outlet 32 and a filtered water outlet 33; the second water outlet 22 is connected to the third water inlet 31 through a second pipe 42; the third water outlet 32 is connected to the first pipe 41 through a return pipe 43; The dosing pipe 4 is connected to the first pipeline 41. The dosing pipe 4 is provided with a dosing valve 401 for controlling the connection or closing of the dosing pipe 4.

[0051] The third water inlet 31 is provided at the bottom of the tubular membrane 3, the third water outlet 32 is provided at the top of the tubular membrane 3, and the filtered water outlet 33 is provided on the sidewall of the top of the tubular membrane 3. The third water inlet 31 is provided at the bottom of the tubular membrane 3 so that during the water treatment process, the bottom of the tubular membrane 3 can be filled with wastewater from bottom to top, allowing the wastewater to fully fill the tubular membrane 3, thereby maximizing the efficiency of the tubular membrane 3 in filtering water.

[0052] The first water inlet 11 is connected to a water inlet pipe 44 , and a water inlet valve 441 is provided on the water inlet pipe 44 for controlling the connection and closing of the water inlet pipe 44 .

[0053] Fluorine-containing wastewater enters the nanobubble generator 1 through the first water inlet 11. Air entering through the air inlet 13 forms nanoscale bubbles in the water due to the shear force in the nanobubble generator 1. The bubbles then flow out of the first water outlet 12. The defluoridation agent enters the first pipe 41 through the dosing pipe 4 and, together with the fluoride-containing wastewater carrying a large number of nanoscale bubbles, enters the spiral pipe mixer 2. The spiral pipe mixer 2 is equipped with a spiral liner and a mixing pipe. The local vortex formed by the spiral liner promotes a full reaction between the defluoridation agent and fluoride ions to form flocculent precipitation. The wastewater then flows through the second pipe 42 from the second water outlet 22 and enters the tubular membrane 3 from the third water inlet 31. The solid and liquid in the wastewater are separated by cross-flow filtration through the tubular membrane 3. The concentrated liquid flows back into the spiral pipe mixer 2 through the reflux pipe 43, and the filtered water flows out through the filtered water outlet 33.

[0054] Nanobubbles and tubular membrane 3 filtration separate the suspension formed after drug addition into solids and liquids, requiring only defluorination agents and no additional flocculants, thus reducing the amount of agents used. The spiral pipe mixer 2 replaces the existing sedimentation tank, and combined with tubular membrane 3 for cross-flow filtration, enriches the precipitated flocs and improves the overall defluorination efficiency of the defluorination agent, effectively solving the problems of existing equipment with large footprints, high agent dosage, and high operating costs.

[0055] In one embodiment, a circulation pump 421 and a circulation valve 422 are provided on the second pipe 42. The circulation pump 421 can deliver wastewater from the spiral pipe mixer 2 to the tubular membrane 3, providing pressure for separation by the tubular membrane 3. The circulation valve 422 can control the flow of water in the second pipe 42. When the tubular membrane 3 needs to be backwashed, the circulation valve 422 can be closed to prevent the backwashing of the tubular membrane 3 from affecting the spiral pipe mixer 2.

[0056] In one embodiment, a reflux valve 431 is provided on the reflux pipe 43. The reflux valve 431 can control the flow and closing of the reflux pipe 43.

[0057] The air inlet 13 is connected to the air pump 5. The air pump 5 can send air into the nano bubble generator 1, so that the nano bubble generator 1 can smoothly generate bubbles.

[0058] In one embodiment, the tubular membrane 3 includes a tubular membrane housing 34 and a tubular membrane column 35 disposed in the tubular membrane housing 34 . The tubular membrane column 35 includes a plurality of silicon carbide layers with gradually decreasing particle sizes from the inside to the outside.

[0059] The tubular membrane column 35 and the tubular membrane housing 34 cooperate to form an outer annular cavity 36, which is connected to the filtered water outlet 33. The tubular membrane column 35 is centrally opened, forming an inner cavity 37 at its center. Wastewater passes through the inner cavity 37, is filtered through the tubular membrane column 35, and then enters the outer annular cavity 36, ultimately flowing out of the filtered water outlet 33.

[0060] The tubular membrane column 35 comprises, from the inside out, a first silicon carbide layer 351 with particles less than 0.5 μm in size, a second silicon carbide layer 352 with particles less than 0.2 μm in size, and a third silicon carbide layer 353 with particles less than 0.05 μm in size. The use of three different silicon carbide particle sizes allows for progressive filtration of wastewater, resulting in enhanced filtration effectiveness. The three layers of silicon carbide are sintered at temperatures exceeding 1500°C in three steps to restructure and bond the three types of particles, giving the tubular membrane 3 excellent chemical resistance.

[0061] In one embodiment, the filtered water outlet 33 is connected to a water outlet pipe 45, which is provided with a water outlet valve 451 for controlling its connection and closure. A backwash pipe 46 is provided between the water outlet valve 451 and the filtered water outlet 33, connected to the water outlet pipe 45. A backwash valve 461 is provided on the backwash pipe 46. A bottom drain pipe 47 is provided at the bottom of the tubular membrane 3, and a bottom drain valve 471 is provided on the bottom drain pipe 47. The second pipe 42 is connected to the bottom drain pipe 47 between the bottom drain valve 471 and the third water inlet 31.

[0062] The structure of this embodiment is similar to that of embodiment 1, except that the tubular membrane 3 is arranged in the vertical direction, and a cleaning member 6 is provided in the tubular membrane column 35 , that is, the cleaning member 6 is arranged in the inner cavity 37 and can slide in the inner cavity 37 .

[0063] The cleaning member 6 includes a cleaning head 61 disposed above and a sinking head 62 disposed below the cleaning head 61. The cleaning head 61 and the sinking head 62 are connected by a rigid connecting rod or a rigid pull rope. In this embodiment, they are connected by a connecting rod 63. The cleaning head 61 includes a cleaning sleeve 611 and a plurality of cleaning bars 612 disposed outside the cleaning sleeve 611. The cleaning bars 612 are disposed on the outer wall of the cleaning sleeve 611 and can contact the inner wall of the tubular membrane column 35. The hollow interior of the cleaning sleeve 611 forms an upper floating cavity 613. When the tubular membrane 3 is filled with wastewater, the buoyancy of the cleaning sleeve 611 drives the cleaning member 6 upward to the top of the tubular membrane column 35. After the wastewater in the tubular membrane 3 is discharged from the bottom, the cleaning member 6 moves downward under the action of gravity, and the cleaning bars 612 clean the inner wall of the tubular membrane column 35. The cleaning strip 612 is made of a material with relatively high hardness, and can clean the inner wall of the tubular membrane column 35 without causing damage to the inner wall.

[0064] In this embodiment, when the wastewater is being treated, the tubular membrane column 35 is filled with wastewater, and the cleaning head 61 is acted upon by buoyancy, driving the entire cleaning member 6 to move upward, with the cleaning head 61 located at the top of the cleaning member 6. When the tubular membrane 3 needs to be backwashed, the bottom discharge valve 471 is opened, and the wastewater in the tubular membrane column 35 is discharged. At this time, the cleaning member 6 moves downward along the inner wall of the tubular membrane column 35 under the action of gravity. During the movement, the cleaning strip 612 can contact the inner wall of the tubular membrane column 35, cleaning impurities attached to the inner wall of the tubular membrane column 35. Therefore, each time backwashing is performed, the cleaning member 6 in this application can clean the inner wall of the tubular membrane column 35, thereby improving the cleaning effect of the inner wall of the tubular membrane column 35.

[0065] In one embodiment, an elastic scraper ring 614 is provided on the outer circumference of the top of the cleaning head 61. The elastic scraper ring 614 conforms to the inner wall of the tubular membrane column 35. Made of a relatively hard rubber material, the elastic scraper ring 614 can clean the inner wall of the tubular membrane column 35 while maintaining the repositioning of the cleaning head 61. As the cleaning strip 612 moves along the inner wall of the tubular membrane column 35, it removes impurities adhering to the inner wall of the tubular membrane column 35, thereby reducing the adhesion of impurities to the inner wall of the tubular membrane 3. Finally, under the action of the elastic scraper ring 614, the impurities on the inner wall of the tubular membrane column 35 are completely cleaned.

[0066] In one embodiment, a shrink sleeve 615 is provided at the top of the inner wall of the cleaning sleeve 611, and the diameter of the shrink sleeve 615 gradually decreases toward the third water inlet 31. The diameter of the shrink sleeve 615 gradually decreases to form a trumpet shape. A reflux groove 616 is formed between the outer periphery of the shrink sleeve 615 and the inner wall of the cleaning sleeve 611, so that when water flows through the shrink sleeve 615, a portion of the water flow will flow into the reflux groove 616, and the reflux groove 616 acts as a barrier to the water flow. Therefore, when wastewater treatment is performed, the impact force of the wastewater on the reflux groove 616 can be used to send the cleaning element 6 to the top of the tubular membrane column 35, so that the cleaning element 6 can clean the inner wall of the tubular membrane column 35 during the next backwash.

[0067] The working principle of this application is as follows: the water inlet valve 441, the dosing valve 401, the backflow valve 431, the circulation valve 422, and the water outlet valve 451 are opened, and the remaining valves are closed. Fluorine-containing wastewater enters the nanobubble generator 1 through the first water inlet 11. The air pump 5 sends air into the nanobubble generator 1 through the air inlet 13. The shear force in the nanobubble generator 1 forms nanoscale bubbles in the water, which then flows out from the first water outlet 12. The defluoridation agent enters the first pipe 41 from the dosing pipe 4 and enters the spiral pipe mixer 2 together with the fluoride-containing wastewater carrying a large number of nanoscale bubbles. The spiral pipe mixer 2 is provided with a spiral liner and a mixing pipe. The local vortex formed by the spiral liner promotes the defluoridation agent to fully react with fluoride ions to form flocculent precipitation; the wastewater then passes through the second pipe 42 from the second water outlet 22 and enters the tubular membrane 3 from the third water inlet 31. The solid and liquid in the wastewater are separated by cross-flow filtration through the tubular membrane 3, and the concentrated liquid is returned to the spiral pipe mixer 2 through the reflux pipe 43. The filtered water flows out from the filter outlet 33 and finally flows out from the outlet pipe 45.

[0068] After the equipment has been running for a certain period of time, the filtered impurities will affect the membrane flux of the tubular membrane 3. Therefore, a backwash pipe 46 is provided. When the tubular membrane 3 needs to be backwashed, the reflux valve 431, circulation valve 422, and outlet valve 451 can be closed, and the backwash valve 461 and bottom drain valve 471 can be opened. Clean water flows from the backwash pipe 46 into the outlet pipe 45, then enters the tubular membrane 3 from the outlet pipe 45, backwashing the tubular membrane 3, discharging impurities from the third water inlet 31, and finally flowing out of the bottom drain valve 471.

[0069] Therefore, this application can be used in conjunction with an automatic control program to control the opening and closing of each valve, automatically switching between the treatment of fluorine-containing wastewater and the backwashing of the tubular membrane 3. The overall equipment can be a civil structure or a skid-mounted equipment, which is easy to move and assemble. It adopts remote control or automatic control, and does not require on-site personnel management.

[0070] The above-described embodiments are only preferred solutions of the present invention and are not intended to limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solutions described in the claims.

Claims

1. A water treatment and defluorination device, characterized in that: include: A nano bubble generator is provided with a first water inlet, an air inlet and a first water outlet; A spiral pipe mixer is provided with a second water inlet and a second water outlet, the first water outlet and the second water inlet are connected through a first pipe; A tubular membrane is provided with a third water inlet, a third water outlet and a filtration water outlet; The second water outlet is connected to the third water inlet through the second pipe; the third water outlet is connected to the first pipe through the return pipe; A dosing pipe communicated with the first pipe.

2. The water treatment and defluorination device according to claim 1, characterized in that: A circulation pump and a circulation valve are provided on the second pipeline.

3. The water treatment and defluorination device according to claim 1, characterized in that: A reflux valve is provided on the reflux pipe.

4. The water treatment and defluorination device according to claim 1, characterized in that: The air inlet is communicated with the air pump.

5. The water treatment and defluorination device according to claim 1, characterized in that: The filter outlet is connected to the outlet pipe, which is provided with an outlet valve. A backwash pipe connected to the outlet pipe is also provided between the outlet valve and the filter outlet, and the backwash pipe is provided with a backwash valve. A bottom discharge pipe is provided at the bottom of the tubular membrane, and a bottom discharge valve is provided on the bottom discharge pipe.

6. The water treatment and defluorination device according to any one of claims 1 to 5, characterized in that: The tubular membrane comprises a tubular membrane shell and a tubular membrane column arranged in the tubular membrane shell. The tubular membrane column comprises a plurality of silicon carbide layers with gradually decreasing particle sizes from the inside to the outside.

7. The water treatment and defluorination device according to claim 6, characterized in that: The tubular membrane column comprises, from inside to outside, a first silicon carbide layer with a particle size less than 0.5 μm, a second silicon carbide layer with a particle size less than 0.2 μm, and a third silicon carbide layer with a particle size less than 0.05 μm.

8. The water treatment and defluorination device according to claim 6, characterized in that: A cleaning piece is provided in the tubular membrane column, and the cleaning piece includes a cleaning head arranged above and a sinking head arranged below the cleaning head; the cleaning head includes a cleaning sleeve and a plurality of cleaning strips arranged outside the cleaning sleeve; the cleaning sleeve is provided with an upper floating cavity; when the tubular membrane is filled with wastewater, the buoyancy of the cleaning sleeve drives the cleaning piece to move upward to the top of the tubular membrane column; after the wastewater in the tubular membrane is discharged from the bottom, the cleaning piece moves downward under the action of gravity, and the cleaning strips clean the inner wall of the tubular membrane column.

9. The water treatment and defluorination device according to claim 8, characterized in that: An elastic scraping ring is arranged on the outer circumference direction of the top of the cleaning head, and the elastic scraping ring is in contact with the inner wall of the tubular membrane column.

10. The water treatment and defluorination device according to claim 8, characterized in that: A shrink sleeve is provided on the top of the inner side wall of the cleaning sleeve, and the diameter of the shrink sleeve gradually decreases towards the direction of the sinking head.

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