Tubular double-membrane ammonia nitrogen removal and recovery device

Abstract

The invention discloses a tubular double-membrane ammonia nitrogen removal and recovery device. The device comprises a shell, a cation exchange membrane and a hollow fiber hydrophobic membrane which are sequentially arranged from outside to inside, a wastewater inlet chamber is formed between the shell and the cation exchange membrane; a driving chamber is formed between the cation exchange membrane and the hollow fiber hydrophobic membrane; a recovery chamber is formed in the hollow fiber hydrophobic membrane; the hollow fiber hydrophobic membrane comprises a plurality of bunchy hollow membrane filaments, and a regulation and control device for adjusting the opening degree is arranged corresponding to an acid liquor inlet of the hollow fiber hydrophobic membrane, so that the number of the membrane filaments participating in acid liquor contact work can be adjusted. Due to the fact that the number of the membrane filaments is adjustable, waste of acid liquor and pollution of the membrane filaments are greatly reduced, meanwhile, due to the fact that the multiple membrane filaments are arranged, efficient mass transfer of ammonia gas is achieved, and the decontamination capacity and the recovery efficiency of the whole device are improved. In addition, due to the reasonable arrangement of the electric driving assembly, composite driving of an electric field and a concentration field can be formed, and then high-concentration ammonia-nitrogen wastewater is effectively treated.

Description

Technical Field

[0001] The present invention relates to the technical field of ecological and environmental protection water treatment, and more specifically, to a tubular double-membrane ammonia nitrogen removal and recovery device. Background Art

[0002] Ammonia nitrogen is one of the main factors of eutrophication of water bodies. The effective treatment and resource utilization of ammonia nitrogen wastewater has important environmental and economic significance. Membrane technology is widely used in the field of ammonia nitrogen removal / recovery due to its advantages of efficient separation. However, traditional membrane technology has the problem of easy membrane pollution and the balance between low energy consumption and high efficiency, and cannot achieve efficient removal and resource recovery of ammonia nitrogen. In recent years, under the background of dual carbon goals and the overall layout of ecological civilization construction, membrane separation coupling technology has been used to replace traditional single membrane separation technology, such as the combination of Daonan dialysis and osmotic distillation, which provides a new solution for the treatment of ammonia nitrogen wastewater. Daonan dialysis is added before osmotic distillation, and cation exchange membrane is used to isolate anions and some high-valent metal cations to enrich ammonia nitrogen from sewage, so that sewage does not directly contact the breathable hydrophobic membrane, so as to achieve the purpose of reducing the pollution of the hydrophobic membrane; the enriched ammonia nitrogen is converted into ammonia gas under alkaline conditions, and then the ammonia gas crosses the hydrophobic membrane into the recovery area. This coupling technology can make full use of the advantages of the membrane separation process. It is driven by natural concentration differences or pressure differences and does not require external energy input. It can achieve green and low-carbon ammonia nitrogen enrichment and resource recovery under "zero energy consumption" conditions, reduce operating costs, and has good economy and environmental friendliness.

[0003] The Daonan dialysis and osmotic distillation coupling component uses a combination of cation exchange membrane and breathable hydrophobic membrane. The common form of cation exchange membrane is flat plate, and the common form of breathable hydrophobic membrane is flat plate or hollow fiber. Flat plate cation exchange membrane and breathable hydrophobic membrane have the following problems: the membrane is easy to wet. The surface area of ​​the flat plate membrane component is usually large, the contact area with the liquid is wide, and the liquid flow path is long, which makes the membrane surface easy to be wetted, affecting the transmembrane transport of ions or gases; the membrane flux is small. The structural design of the flat plate membrane component usually limits the flow mode and speed of the liquid or gas, resulting in reduced mass transfer efficiency and reduced membrane flux. In addition, ions are prone to concentration polarization during the transmembrane transport of the flat plate membrane component, which will also cause the membrane flux to decrease; the membrane process power is low, and the existing flat plate membrane components are difficult to have an optimized fluid mechanics design, resulting in the limitation and singularity of wastewater flow during operation, and the driving force of the membrane separation process is low; the integration (filling) density is low. Since the membrane area per unit volume of the flat plate membrane component is relatively small, the flat plate component cannot fill more membrane area in a certain space. At the same time, the Daonan dialysis and osmotic distillation coupling assembly, which is composed of a flat-plate cation exchange membrane and a flat-plate hydrophobic membrane assembly connected in series, has the shortcomings of the above-mentioned single flat-plate membrane assembly, such as easy membrane contamination and wetting, small membrane flux, low membrane process power, low integration density, and large floor space. In addition, since the spacing between the flat-plate membrane assemblies is a large plane, wastewater is prone to produce local eddies and dead water areas when passing through. These areas often accumulate pollutants, leading to membrane blockage and pollution problems, especially the four dead corners are prone to scaling and difficult to clean, and special chemicals and procedures are required for cleaning, resulting in increased costs. Moreover, the existing Daonan dialysis and osmotic distillation coupling assemblies are all modular, requiring pipe connections, occupying a large area, and the overall mass transfer and reaction rate are slow, affecting the separation performance of ammonia nitrogen.

[0004] In summary, the above problems restrict the application and promotion of the flat-plate type Donan dialysis and osmotic distillation coupling assembly to remove and recover ammonia nitrogen. There is no technology to realize the coupling of Donan dialysis and osmotic distillation with other shapes of membrane components. Summary of the invention

[0005] Based on the above technical problems, the purpose of the present invention is to provide a tubular double-membrane ammonia nitrogen removal and recovery device, which can overcome the defects of the existing flat-plate components coupled with Donan dialysis and osmotic distillation. The entire decontamination process is carried out under natural concentration difference and / or electric drive, thereby achieving efficient ammonia nitrogen removal and resource recovery.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] The invention discloses a tubular double-membrane ammonia nitrogen removal and recovery device, comprising a shell, a cation exchange membrane and a hollow fiber hydrophobic membrane, wherein the shell has a hollow inner cavity; the cation exchange membrane is a tubular structure and is arranged in the hollow inner cavity of the shell; the hollow fiber hydrophobic membrane is a tubular structure and is arranged in the inner cavity of the cation exchange membrane; a wastewater inlet chamber is formed between the shell and the cation exchange membrane; a drive chamber is formed between the cation exchange membrane and the hollow fiber hydrophobic membrane; a recovery chamber is formed inside the hollow fiber hydrophobic membrane; wherein the wastewater inlet chamber is configured to receive input of ammonia nitrogen wastewater to be treated, the drive chamber is configured to receive input of external drive liquid, and the recovery chamber is configured to receive input of external acid solution and output ammonium salt to the outside; the hollow fiber hydrophobic membrane comprises a plurality of closely arranged bundled hollow membrane fibers, and a control device capable of adjusting the opening and closing degree of the acid solution inlet is provided corresponding to the acid solution inlet of the hollow fiber hydrophobic membrane, so that the number of membrane fibers participating in the acid solution contact work in all the bundled hollow membrane fibers can be adjusted.

[0008] The so-called tubular structure refers to a structure with a circular radial cross section. In the present invention, the housing, the cation exchange membrane and the hollow fiber hydrophobic membrane are arranged in sequence from the inside to the outside, and there is a chamber (i.e., a wastewater inlet chamber) between the housing and the cation exchange membrane, a chamber (i.e., a driving chamber) between the cation exchange membrane and the hollow fiber hydrophobic membrane, and a chamber (i.e., a recovery chamber) in the hollow fiber hydrophobic membrane, so that the device of the present invention is constituted as a three-chamber two-membrane structure in layers.

[0009] In the above scheme, the ammonia nitrogen wastewater to be treated enters the outer shell from the wastewater inlet chamber, and the ammonium ions contained in the ammonia nitrogen wastewater to be treated enter the driving chamber through the cation exchange membrane under the action of the concentration difference (i.e., natural concentration difference). The driving liquid in the driving chamber is an alkaline liquid, which reacts with the entering ammonium ions to generate ammonia water, and the ammonia water decomposes into ammonia gas and water. Due to the difference in ammonia partial pressure between the driving chamber and the recovery chamber, the ammonia gas enters the recovery chamber through the hollow fiber hydrophobic membrane, contacts with the bundled hollow membrane fibers regulated by the regulating device in the recovery chamber, and enters the bundled hollow membrane fibers participating in the acid contact work, and finally reacts under the action of the acid to generate liquid ammonium salt and is recovered.

[0010] In the deamination process, the mass transfer rate of ammonia is limited by the osmotic distillation (OD) process, that is, the process of ammonia passing through the hollow fiber hydrophobic membrane (GPM). In the prior art, the area of ​​the cation exchange membrane (CEM) is larger than that of the hollow fiber hydrophobic membrane (GPM), which is not conducive to the mass transfer process of ammonia. In the device of the present invention, since the device is constructed as a single cation exchange membrane corresponding to a plurality of hollow fiber hydrophobic membranes, that is, it is constructed in the form of "1 to N", the area of ​​the hollow fiber hydrophobic membrane (GPM) is smaller than that of the cation exchange membrane (GPM) in the prior art, and a larger membrane contact area can be provided for ammonia passing through the hollow fiber hydrophobic membrane (GPM), thereby promoting the transfer of ammonia from the driving chamber to the recovery chamber during the deamination process, thereby improving the mass transfer efficiency of ammonia.

[0011] Moreover, since the number of bundled hollow membrane filaments in the hollow fiber hydrophobic membrane that participate in the acid contact work can be regulated, when some bundled hollow membrane filaments are contaminated, other bundled hollow membrane filaments can still carry out the mass transfer process normally, avoiding the risk of membrane contamination of the entire system and improving the reliability of the device operation.

[0012] In the tubular double-membrane ammonia nitrogen removal and recovery device disclosed in the present invention, the control device is constructed to determine the opening and closing degree of the acid solution inlet of the central control fiber hydrophobic membrane based on the concentration of the ammonia nitrogen wastewater to be treated.

[0013] That is, the control device of the present invention can adapt to the concentration changes of the ammonia nitrogen wastewater to be treated, and adjust the opening and closing degree of the acid liquid inlet of the hollow fiber hydrophobic membrane according to the change of the concentration of the ammonia nitrogen wastewater to be treated. When the concentration of the ammonia nitrogen wastewater becomes higher, the opening and closing degree of the acid liquid inlet of the hollow fiber hydrophobic membrane adjusted by the control device becomes larger, thereby increasing the number of membrane filaments participating in the acid liquid contact work in the bundled hollow membrane filaments; when the concentration of the ammonia nitrogen wastewater becomes lower, the opening and closing degree of the acid liquid inlet of the hollow fiber hydrophobic membrane adjusted by the control device becomes smaller, thereby reducing the number of membrane filaments participating in the acid liquid contact work in the bundled hollow membrane filaments. In other words, the control device of the present invention can control the number of membrane filaments participating in the acid liquid contact work in the bundled hollow membrane filaments according to the concentration changes of the ammonia nitrogen wastewater to be treated, thereby improving the operational flexibility of the device of the present invention.

[0014] Furthermore, since the opening and closing degree of the acid inlet of the hollow fiber hydrophobic membrane adjusted by the control device is determined based on the concentration of the ammonia nitrogen wastewater to be treated, the opening and closing of the acid inlet of the hollow fiber hydrophobic membrane corresponds to the bundled hollow membrane filaments that will be involved in the work, and thus the number of membrane filaments in the bundled hollow membrane filaments that participate in the acid contact work is determined based on the concentration of the ammonia nitrogen wastewater to be treated, thereby effectively avoiding the waste of acid and the pollution of the bundled hollow membrane filaments, and saving economic costs.

[0015] In the present invention, the opening degree of the acid solution inlet of the hollow fiber hydrophobic membrane is actually the size of the opening of the regulating device.

[0016] In a specific embodiment, the opening and closing opening of the regulating device corresponds to the bundled hollow membrane filaments that will be involved in the work, and the external acid enters the bundled hollow membrane filaments that will be involved in the work through the opening and closing opening of the regulating device. When the opening and closing opening of the regulating device is larger, the number of bundled hollow membrane filaments corresponding to the opening and closing opening is more, and thus the number of bundled hollow membrane filaments that will be involved in the work is more; when the opening and closing opening of the regulating device is smaller, the number of bundled hollow membrane filaments corresponding to the opening and closing opening is smaller, and thus the number of bundled hollow membrane filaments that will be involved in the work is smaller, so the size of the opening and closing opening of the regulating device is positively correlated with the number of bundled hollow membrane filaments that will be involved in the work.

[0017] In the present invention, the size of the opening and closing mouth of the control device is determined based on the concentration of the ammonia nitrogen wastewater to be treated. Specifically, the concentration of the ammonia nitrogen wastewater to be treated is mainly divided into low-concentration ammonia nitrogen wastewater, medium-concentration ammonia nitrogen wastewater and high-concentration ammonia nitrogen wastewater. The opening and closing mouth of the control device can be adjusted to 20%, 50% and 100%, etc., wherein the opening and closing mouth of the control device is 20% corresponding to low-concentration ammonia nitrogen wastewater, the opening and closing mouth of the control device is 50% corresponding to medium-concentration ammonia nitrogen wastewater, and the opening and closing mouth of the control device is 100% corresponding to high-concentration ammonia nitrogen wastewater.

[0018] Furthermore, when the opening and closing size of the regulating device is 20%, the bundled hollow membrane filaments to be involved in the work are the hollow fiber membrane filaments corresponding to the opening and closing size of 20%; when the opening and closing size of the regulating device is 50%, the bundled hollow membrane filaments to be involved in the work are the hollow fiber membrane filaments corresponding to the opening and closing size of 50%; when the opening and closing size of the regulating device is 100%, the bundled hollow membrane filaments to be involved in the work are the hollow fiber membrane filaments corresponding to the opening and closing size of 100%, that is, the bundled hollow membrane filaments participating in the acid contact work are determined according to the concentration of the ammonia nitrogen wastewater to be treated.

[0019] In the tubular double-membrane ammonia nitrogen removal and recovery device disclosed in the present invention, the regulating device includes a paddle, a chassis and a plurality of opening and closing blades, the paddle and the chassis are respectively provided with slide grooves, the slide grooves of the paddle and the chassis form a certain angle in space, a sliding column is provided on the opening and closing blades, the sliding column is positioned in the slide groove, the chassis can be driven to rotate, and the sliding column slides in the slide groove through the rotation of the chassis, and with the help of repeated sliding of the sliding column in the slide groove, the opening and closing blades are close to and away from the center position, thereby adjusting the opening and closing range of the regulating device.

[0020] In the tubular double-membrane ammonia nitrogen removal and recovery device disclosed in the present invention, the number of the slide grooves provided on the paddle, the slide grooves provided on the chassis and the slide columns provided on the blades correspond to each other.

[0021] In the tubular double-membrane ammonia nitrogen removal and recovery device disclosed in the present invention, an acid distributor is arranged above the regulating device, and the acid distributor inputs external acid into the bundled hollow membrane fibers of the hollow fiber hydrophobic membrane through the opening and closing port of the regulating device.

[0022] In the prior art for treating ammonia nitrogen wastewater, either based on concentration difference drive (i.e., natural concentration difference drive) or based on electric drive, there is a lack of an ammonia nitrogen wastewater treatment device that effectively combines the two drive modes and has a reasonable structure. In addition, when the prior art treats high-concentration ammonia nitrogen wastewater, relying solely on concentration difference drive will cause problems such as low system mass transfer rate and limited processing capacity. Even if this contradiction can be alleviated by the conventional practice of laying more components in the prior art, this will increase the cost of engineering investment. To solve these problems, in the tubular double-membrane ammonia nitrogen removal and recovery device disclosed in the present invention, an electric drive component is also included, and the electric drive component includes: an anode metal mesh, which is configured as a tubular structure and is arranged between the housing and the cation exchange membrane; a cathode metal mesh, which is configured as a tubular structure and is arranged between the cation exchange membrane and the hollow fiber hydrophobic membrane; the anode metal mesh is connected to the positive electrode of the power supply, and the cathode metal mesh is connected to the negative electrode of the power supply. When the anode metal mesh and the cathode metal mesh are powered on, the wastewater inlet chamber is formed as an anode chamber, and the drive chamber can be formed as a cathode chamber. Based on this structural setting, when the concentration of ammonia nitrogen wastewater is high, the present invention can apply electric drive at the same time, and the technology of the present invention is transformed from simple Donan dialysis and osmotic distillation coupling to remove and recover ammonia nitrogen to electrodialysis-Donan dialysis composite drive and coupled with osmotic distillation to remove and recover ammonia nitrogen, that is, the technical implementation path of the present invention is changed to a tubular double-membrane ammonia nitrogen removal and recovery device driven by electric field and concentration field. That is, in the present invention, more efficient ammonia nitrogen mass transfer can be achieved by electric drive (such as electrodialysis). This makes it possible for electric drive and concentration drive to be flexibly deployed in the present invention. When treating high-concentration ammonia nitrogen wastewater, if the concentration drive effect is not ideal, it can be switched to electric field and concentration field composite drive to recover ammonia nitrogen.

[0023] Wherein, based on the aforementioned electric drive assembly, in the present invention, an anode chamber is formed between the anode metal mesh and the cation exchange membrane, and a cathode chamber is formed between the cation exchange membrane and the cathode metal mesh, wherein the anode chamber is located in the wastewater inlet chamber, and the cathode chamber is located in the drive chamber. In the anode chamber, an oxygen evolution reaction occurs on the anode metal mesh, and water molecules lose electrons and are oxidized to generate oxygen and hydrogen ions; in the cathode chamber, a hydrogen evolution reaction occurs on the cathode metal mesh, and water molecules obtain electrons and are reduced to generate hydrogen and hydroxide ions. The specific working process is: first, ammonia-containing waste liquid enters the anode chamber, and ammonium ions enter the cathode chamber through the cation exchange membrane under the drive of an external electric field; secondly, ammonium ions combine with hydroxide ions generated by the cathode metal mesh to generate free gaseous ammonia molecules, and ammonia enters the recovery chamber due to the difference in ammonia partial pressure between the cathode chamber and the recovery chamber; then gaseous ammonia combines with hydrogen ions in the acid solution in the recovery chamber to generate ammonium ions, which are finally recovered in the form of liquid ammonium salts.

[0024] The electric drive recovery of ammonia nitrogen of the present invention causes the ammonium ions in the wastewater inlet chamber to migrate in a directional manner through the electric field generated by the anode metal mesh and the cathode metal mesh, which greatly accelerates the speed at which the ammonium ions pass through the cation exchange membrane, improves the deammoniation efficiency and the overall operation efficiency of the device; and the hydroxide ions generated on the cathode metal mesh in the driving chamber can directly react with the ammonium ions migrated from the wastewater inlet chamber to generate ammonia gas, thereby reducing the consumption of chemicals and being environmentally friendly; and the cathode metal mesh shortens the distance from the hollow fiber hydrophobic membrane, so that under the action of the electric field, the ammonia gas generated near the cathode metal mesh can be quickly transferred to the hollow fiber hydrophobic membrane, effectively avoiding The accumulation and reverse diffusion of ammonia gas are solved, thereby improving the removal efficiency and stability of the entire system; in addition, under the action of the electric field, the negatively charged organic molecules in the wastewater inlet chamber move toward the anode metal mesh, avoiding contact with the cation exchange membrane, thereby reducing the risk of cation exchange membrane contamination, and at the same time avoiding the problem of reduced membrane flux caused by the contact and interaction between the negatively charged organic molecules and the cation exchange membrane, affecting the mass transfer efficiency; finally, the device of the present invention can flexibly adjust the operating parameters such as voltage and current according to the concentration changes of the ammonia nitrogen wastewater to be treated, thereby improving the coping ability of the device, maintaining the best treatment performance under various environmental conditions, and realizing efficient removal of ammonia nitrogen.

[0025] In the tubular double-membrane ammonia nitrogen removal and recovery device disclosed in the present invention, the anode metal mesh is a titanium mesh coated with Ir mixed metal oxides, and / or the cathode metal mesh is a stainless steel diamond grid.

[0026] In the tubular double-membrane ammonia nitrogen removal and recovery device disclosed in the present invention, the wastewater inlet chamber is provided with a spiral water inlet corridor for receiving the input of the ammonia nitrogen wastewater to be treated, and the spiral water inlet corridor is formed by spirally winding from top to bottom along the outer side of the cation exchange membrane. The spiral water inlet corridor prolongs the inflow path of the ammonia nitrogen wastewater to be treated, increases the contact time with the cation exchange membrane, and improves the mass transfer efficiency and deammoniation efficiency; and the spiral flow field formed can enhance turbulent flow and reduce the concentration polarization phenomenon occurring on the surface of the cation exchange membrane; and the spiral water inlet can also increase the tangential flow velocity of the water flow, has a flushing effect on the cation exchange membrane, and reduces the deposition of pollutants on the surface of the cation exchange membrane; in addition, the spiral water inlet corridor can also make the ammonia nitrogen wastewater flow more evenly through the surface of the cation exchange membrane, reduce the formation of local high concentration areas, thereby reducing the risk of cation exchange membrane contamination and extending the service life of the cation exchange membrane.

[0027] In the tubular double-membrane ammonia nitrogen removal and recovery device disclosed in the present invention, the spiral angle of the spiral water inlet gallery is 15° to 25°, and the angle between the spiral water inlet gallery and the cation exchange membrane is 45°. A smaller spiral angle can maintain the stability of the flow of ammonia nitrogen wastewater, while a larger spiral angle can increase the tangential velocity of the fluid, thereby enhancing the shear force and achieving the flushing of pollutants on the surface of the cation exchange membrane. Preferably, the spiral angle of the spiral water inlet gallery is 15° to 25°; and the angle between the spiral water inlet gallery and the cation exchange membrane is 45°, which can form an impact force in the tangential direction, have a flushing effect on the cation exchange membrane, and prevent the cation exchange membrane from being contaminated.

[0028] In the tubular double-membrane ammonia nitrogen removal and recovery device disclosed in the present invention, a mesh support member is provided on the outer side and / or inner side of the cation exchange membrane. The provided mesh support member can evenly disperse the pressure impact on the cation exchange membrane caused by the inflow of ammonia nitrogen wastewater to be treated, effectively avoiding the risk of damage to the surface of the cation exchange membrane due to excessive local pressure; and the geometric configuration of the mesh support member reduces the pressure drop in the flow channel and reduces energy consumption; and it can also increase additional mechanical strength, which helps to maintain the stability of the system when facing fluid pressure fluctuations. Among them, the thickness of the mesh support member can be 1 to 3 mm.

[0029] The beneficial effects of the present invention are as follows:

[0030] 1) The present invention innovatively provides an ammonia nitrogen wastewater treatment and recovery device, the overall structure of which is a tubular structure with three chambers and two membranes, thereby forming an integrated device based on the coupling of Donan dialysis and osmotic distillation. The opening and closing degree of the acid liquid inlet of the hollow fiber hydrophobic membrane is adjusted by a control device, so that the number of membrane fibers participating in the acid liquid contact work in the bundled hollow membrane fibers of the hollow fiber hydrophobic membrane can be adjusted, thereby improving the operational flexibility of the entire device; and by controlling the contact between the bundled hollow membrane fibers and the acid liquid through the control device, the waste of acid liquid and the pollution of the bundled hollow membrane fibers can be reduced, thereby saving economic costs.

[0031] 2) In the device of the present invention, since the device is constructed as a single cation exchange membrane corresponding to a plurality of hollow fiber hydrophobic membranes, that is, it is constructed in the form of "1 to N", compared with the area of ​​the hollow fiber hydrophobic membrane in the prior art, which is smaller than the area of ​​the cation exchange membrane, it can provide a larger membrane contact area for ammonia passing through the hollow fiber hydrophobic membrane, thereby promoting the transfer of ammonia from the driving chamber to the recovery chamber during the deammoniation process, thereby improving the mass transfer efficiency of ammonia.

[0032] 3) In the device of the present invention, since the number of bundled hollow membrane fibers participating in the acid liquid contact work in the hollow fiber hydrophobic membrane can be controlled, when some bundled hollow membrane fibers are contaminated, other bundled hollow membrane fibers can still carry out the mass transfer process normally, thus avoiding the risk of membrane contamination of the entire system and improving the reliability of the device operation.

[0033] The tubular double-membrane ammonia nitrogen removal and recovery device of the present invention is disclosed in detail below in conjunction with the embodiments shown in the accompanying drawings and the figure numerals. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a cross-sectional view of the device of the present invention;

[0035] Figure 2 A top view of the device of the present invention;

[0036] Figure 3 This is a schematic diagram of the state when the opening and closing size of the control device of the present invention is 20%;

[0037] Figure 4 This is a schematic diagram of the state in which the opening and closing size of the control device of the present invention is 30%;

[0038] Figure 5 It is a schematic diagram of the state when the opening and closing size of the control device of the present invention is 100%;

[0039] Figure 6 A schematic diagram of the structural coordination of the opening and closing blades and the paddle of the control device of the present invention;

[0040] Figure 7 This is a schematic diagram of the structural coordination between the opening and closing blades and the chassis of the control device of the present invention;

[0041] Figure 8 This is a simplified structural diagram of the spiral water inlet gallery provided in the wastewater inlet chamber of the present invention.

[0042] Reference numerals

[0043] 1 housing, 2 cation exchange membrane, 3 hollow fiber hydrophobic membrane, 4 wastewater inlet chamber, 5 drive chamber, 6 recovery chamber, 7 bundled hollow membrane filaments, 8 paddles, 9 chassis, 10 opening and closing blades, 11 slide column, 12 anode metal mesh, 13 cathode metal mesh, 14 spiral water inlet gallery, 15 mesh support member, 16 arc-shaped guide chute, 17 strip guide chute, 18 chassis handle, 19 ammonia nitrogen wastewater inlet, 20 ammonia nitrogen wastewater outlet, 21 drive liquid inlet, 22 drive liquid outlet, 23 acid liquid inlet, 24 liquid ammonium salt outlet. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other without conflict.

[0045] In view of the defects of the existing flat-plate components of the coupling of Donan dialysis and osmotic distillation, the present invention discloses a tubular double-membrane ammonia nitrogen removal and recovery device. The pollutant removal process of the device can be driven by natural concentration difference or pressure difference, without the need for external energy input, and can achieve green and low-carbon ammonia nitrogen removal and resource recovery under "zero energy consumption" conditions.

[0046] like Figure 1 and Figure 2As shown, the tubular double-membrane ammonia nitrogen removal and recovery device disclosed in the present invention comprises a shell 1, a cation exchange membrane 2 and a hollow fiber hydrophobic membrane 3, wherein the shell 1 has a hollow inner cavity; the cation exchange membrane 2 is a tubular structure and is arranged in the hollow inner cavity of the shell 1; the hollow fiber hydrophobic membrane 3 is a tubular structure and is arranged in the inner cavity of the cation exchange membrane 2; a wastewater inlet chamber 4 is formed between the shell 1 and the cation exchange membrane 2; a driving chamber 5 is formed between the cation exchange membrane 2 and the hollow fiber hydrophobic membrane 3; the inner cavity of the hollow fiber hydrophobic membrane 3 A recovery chamber 6 is formed; wherein the wastewater inlet chamber 4 is constructed to be able to accept the input of ammonia nitrogen wastewater to be treated, the drive chamber 5 is constructed to be able to accept the input of external drive liquid, and the recovery chamber 6 is constructed to be able to accept the input of external acid liquid and output ammonium salt to the outside; the hollow fiber hydrophobic membrane 3 includes a plurality of closely arranged bundled hollow membrane fibers 7, and a control device capable of adjusting the opening and closing degree of the acid liquid inlet is provided corresponding to the acid liquid inlet of the hollow fiber hydrophobic membrane 3, so that the number of membrane fibers participating in the acid liquid contact work in all the bundled hollow membrane fibers 7 can be adjusted.

[0047] Among them, the wastewater inlet chamber 4 has an ammonia nitrogen wastewater inlet 19 and an ammonia nitrogen wastewater outlet 20, the driving chamber 5 has a driving liquid inlet 21 and a driving liquid outlet 22, and the recovery chamber has an acid liquid inlet 23 and a liquid ammonium salt outlet 24. The ammonia nitrogen wastewater inlet 19 and the acid liquid inlet 23 are located on the upper side of the shell 1, the ammonia nitrogen wastewater outlet 20 and the liquid ammonium salt outlet 24 are located on the lower side of the shell 1, and the driving liquid inlet 21 and the driving liquid outlet 22 are respectively located on the upper left side and the lower right side of the shell 1.

[0048] In the present invention, the material of the shell 1 can be polyethylene, polypropylene, stainless steel, etc., the cation exchange membrane 2 and the hollow fiber hydrophobic membrane 3 are nested in structure, sealed by sealant and sealing rings, and sealing rings are provided at the two top ends to ensure the sealing of the assembly. The ammonia nitrogen wastewater enters the membrane assembly in the peripheral water inlet, and the liquid ammonium salt outlet is the central water outlet.

[0049] In the embodiment of the present invention, the driving liquid of the driving chamber 5 is one of a soda solution, a waste alkali solution and a saline solution, such as common soda or waste alkali solutions such as sodium hydroxide (NaOH) and potassium hydroxide (KOH), wherein the ratio of ammonium radicals to hydroxide radicals in the saline solution can be 1:1-2, such as 1:1, 1:1.2 and 1:1.5, etc., and the molar concentration ratio of cations in the driving liquid to ammonia nitrogen in the wastewater to be treated is 1:1-100, such as 1:20, 1:40, 1:60, etc., and by adjusting the ratio, it is ensured that the removal efficiency of ammonia nitrogen is improved under low-cost conditions. In this embodiment, the ammonium radical ions in the wastewater inlet chamber 4 and the driving ions in the driving chamber 5 are replaced across the cation exchange membrane 2 under the action of the concentration difference, and under alkaline conditions, the ammonium radical ions passing through the cation exchange membrane 2 are converted into ammonia gas.

[0050] In the embodiment of the present invention, the acid solution in the recovery chamber 6 is a mixture of one or more common acid solutions such as sulfuric acid (H2SO4) and hydrochloric acid (HCl), wherein the ratio of the multiple mixed acid solutions can be 1:1-2, such as 1:1, 1:1.2 and 1:1.5, etc., and different high-concentration ammonium salt products can be obtained by different acid solutions. The molar concentration ratio of hydrogen ions in the acid solution to ammonia nitrogen in the wastewater to be treated is 1:1-2.5, such as 1:1, 1:1.5, 1:2, etc., and the recovery efficiency of ammonia nitrogen can be improved under low-cost conditions by adjusting the ratio. In this embodiment, ammonia gas enters the recovery chamber 6 through mass transfer across the hollow fiber hydrophobic membrane 3 under the action of the pressure difference on both sides of the hollow fiber hydrophobic membrane 3, and is then converted into an ammonium salt product.

[0051] Preferably, a driving pump is provided in the driving chamber 6 to control the flow rate of the driving liquid and reduce the concentration polarization phenomenon on the membrane surface of the cation exchange membrane 2 .

[0052] The cation exchange membrane 2 of the present invention can selectively pass cations and intercept anions. The driving force is concentration difference driven and no energy consumption is generated. The main component of the hollow fiber hydrophobic membrane 3 is PVDF, which has high mechanical strength, acid and alkali resistance, and strong impact resistance. The sealant can form a sealing layer through spraying / coating and baking processes to enhance the sealing effect and ensure the sealing of the membrane assembly.

[0053] In the present invention, the opening and closing degree of the acid liquid inlet of the hollow fiber hydrophobic membrane 3 is adjusted by the control device, so that the number of membrane fibers in the bundled hollow membrane fibers 7 of the hollow fiber hydrophobic membrane 3 that participate in the acid liquid contact work can be adjusted, thereby improving the flexibility of the entire device in operation; and the contact between the bundled hollow membrane fibers 7 and the acid liquid is regulated by the control device, which can also reduce the waste of the acid liquid and the pollution of the bundled hollow membrane fibers 7, thereby saving economic costs;

[0054] Secondly, the device of the present invention constructs a single cation exchange membrane 2 corresponding to a plurality of hollow fiber hydrophobic membranes 3, that is, it is constructed in a "1 to N" form. Compared with the prior art, the area of ​​the hollow fiber hydrophobic membrane is smaller than the area of ​​the cation exchange membrane, which can provide a larger membrane contact area for ammonia to pass through the hollow fiber hydrophobic membrane 3, thereby promoting the transfer of ammonia from the driving chamber 5 to the recovery chamber 6 during the deammoniation process, thereby improving the mass transfer efficiency of ammonia;

[0055] In addition, since the number of bundled hollow membrane fibers 7 participating in the acid liquid contact work in the hollow fiber hydrophobic membrane 3 can be regulated, when some bundled hollow membrane fibers 7 are contaminated, other bundled hollow membrane fibers 7 can still carry out the mass transfer process normally, avoiding the risk of membrane contamination of the entire system and improving the reliability of the device operation.

[0056] like Figure 3-Figure 5As shown, in a preferred embodiment, the size of the opening and closing mouth of the control device is determined based on the concentration of the ammonia nitrogen wastewater to be treated. Specifically, the concentration of the ammonia nitrogen wastewater to be treated is mainly divided into low-concentration ammonia nitrogen wastewater, medium-concentration ammonia nitrogen wastewater and high-concentration ammonia nitrogen wastewater. The opening and closing mouth of the control device can be adjusted to 20%, 50% and 100%, etc., wherein the opening and closing mouth of the control device is 20% corresponding to low-concentration ammonia nitrogen wastewater, the opening and closing mouth of the control device is 50% corresponding to medium-concentration ammonia nitrogen wastewater, and the opening and closing mouth of the control device is 100% corresponding to high-concentration ammonia nitrogen wastewater.

[0057] Furthermore, when the concentration of low-concentration ammonia-nitrogen wastewater increases to medium-concentration ammonia-nitrogen wastewater, the opening and closing size of the control device is adjusted from 20% to 50%, and when the concentration of medium-concentration ammonia-nitrogen wastewater increases to high-concentration ammonia-nitrogen wastewater, the opening and closing size of the control device is adjusted from 50% to 100%; on the contrary, when the concentration of high-concentration ammonia-nitrogen wastewater decreases to medium-concentration ammonia-nitrogen wastewater, the opening and closing size of the control device is adjusted from 100% to 50%, and when the concentration of medium-concentration ammonia-nitrogen wastewater decreases to low-concentration ammonia-nitrogen wastewater, the opening and closing size of the control device is adjusted from 50% to 20%. The adjustment of the opening and closing size of the control device is based on actual conditions.

[0058] In the present invention, the opening and closing opening of the regulating device is the opening and closing opening of the acid liquid inlet of the hollow fiber hydrophobic membrane 3, that is, the opening and closing opening size of the acid liquid inlet of the hollow fiber hydrophobic membrane 3 is determined based on the concentration of the ammonia nitrogen wastewater to be treated, and the regulating device can determine the opening and closing degree of the acid liquid inlet of the hollow fiber hydrophobic membrane 3 according to the concentration of the ammonia nitrogen wastewater to be treated.

[0059] The present invention controls the number of bundled hollow membrane filaments 7 participating in the acid liquid contact work by adjusting the opening and closing size of the regulating device. The larger the opening and closing size of the regulating device, the more corresponding bundled hollow membrane filaments 7 are adjusted, and the more bundled hollow membrane filaments 7 participating in the acid liquid contact work; the smaller the opening and closing size of the regulating device, the fewer corresponding bundled hollow membrane filaments 7 are adjusted, and the fewer bundled hollow membrane filaments 7 participating in the acid liquid contact work. The opening and closing size of the regulating device is determined based on the concentration of the ammonia nitrogen wastewater to be treated, and thus the number of bundled hollow membrane filaments 7 participating in the acid liquid contact work is determined based on the concentration of the ammonia nitrogen wastewater to be treated, thereby effectively avoiding the waste of acid liquid and the pollution of the bundled hollow membrane filaments 7, saving economic costs.

[0060] like Figure 6 and Figure 7As shown, in the embodiment of the present invention, the regulating device includes a paddle 8, a chassis 9 and a plurality of opening and closing blades 10, the paddle 8 is provided with an arc-shaped guide slot 16, the chassis 9 is provided with a strip-shaped guide slot 17, the arc-shaped guide slot 16 and the strip-shaped guide slot 17 form a certain angle in space, a slide column 11 is provided through the opening and closing blade 10, and the two ends of the slide column 11 are respectively positioned in the arc-shaped guide slot 16 and the strip-shaped guide slot 17, and a chassis handle 18 is provided on the end surface of the chassis 9. The chassis handle 18 is toggled to open and close the blade 10. 8 makes the chassis 9 rotate, and under the action of the rotation of the chassis 9, the slide post 11 slides in the arc-shaped guide slot 16 and the strip-shaped guide slot 17 at the same time. Since the arc-shaped guide slot 16 and the strip-shaped guide slot 17 form a certain angle in space, under the constraint of the slots of the two, when the slide post 11 slides repeatedly in the arc-shaped guide slot 16 and the strip-shaped guide slot 17 at the same time, the opening and closing blade 10 will move closer to and away from the center position of the chassis 9 or the paddle 8, thereby adjusting the size of the opening and closing opening of the control device. In this embodiment, the number of the arc-shaped guide slot 16 provided on the paddle 8, the strip-shaped guide slot 17 provided on the chassis 9, and the slide post 11 provided on the opening and closing blade 10 corresponds to each other, and preferably twelve are provided for each.

[0061] Furthermore, an annular boss is provided inside the housing 1, and a transverse through hole is provided outside along the circumferential surface direction corresponding to the annular boss. The chassis 9 is supported and arranged on the annular boss, and its chassis handle 18 extends out of the housing 1 through the transverse through hole of the housing 1. The size of the chassis handle 18 is adapted to the transverse through hole. The chassis handle 18 is moved in the transverse through hole of the housing 1, so that the chassis 9 is rotated on the annular boss, and the opening and closing blades of the regulating device are opened and closed. The design length of the transverse through hole on the housing 1 is based on the maximum and minimum opening and closing opening of the regulating device when the chassis handle 18 is moved.

[0062] In the embodiment of the present invention, an acid distributor 12 is arranged above the regulating device, and the acid distributor 12 inputs external acid into the bundled hollow membrane fibers 7 of the hollow fiber hydrophobic membrane 3 through the opening and closing port of the regulating device.

[0063] The specific working process of the device of the present invention is as follows: the ammonia nitrogen wastewater to be treated enters the wastewater inlet chamber 4 from the ammonia nitrogen wastewater inlet 19, and the ammonium ions contained in the ammonia nitrogen wastewater in the wastewater inlet chamber 4 enter the driving chamber 5 through the cation exchange membrane 2 under the action of the concentration difference. At the same time, the external driving liquid enters the driving chamber through the driving liquid inlet 21. The driving liquid is alkaline. The driving liquid in the driving chamber 5 reacts chemically with the ammonium ions to generate an ammonia solution, and the ammonia solution decomposes into ammonia gas and water. Due to the difference in ammonia partial pressure between the driving chamber 5 and the recovery chamber 6, the ammonia gas generated in the driving chamber 5 enters the recovery chamber 6 through the hollow fiber hydrophobic membrane 3, contacts with the bundled hollow membrane filaments 7 regulated by the regulating device in the recovery chamber 6, and enters the bundled hollow membrane filaments 7 participating in the acid contact work, and finally reacts under the action of the acid to generate liquid ammonium salt, which is recovered.

[0064] Compared with the prior art, the present invention has the following advantages:

[0065] 1) Starting from membrane wetting, the present invention proposes for the first time an innovative tubular double-membrane ammonia nitrogen removal and recovery device, forming a three-cavity two-membrane structure, which can better control the uniform distribution and flow of the liquid in the tube, reduce the thickness of the liquid film layer and prevent pollutants from accumulating on the membrane surface, while also reducing dead water areas and flow dead corners, reducing the risk of membrane wetting.

[0066] 2) Starting from membrane pollution, the present invention adopts a nested manner in which a cation exchange membrane is on the outside and a hollow fiber hydrophobic membrane is on the inside. The cation exchange membrane on the outside can serve as a barrier to isolate anions and some high-valent metal ions, separate sewage from the hydrophobic membrane, and achieve the purpose of reducing hydrophobic membrane pollution; the cation exchange membrane on the outside can separate the alkali solution from the wastewater, avoiding the interaction between impurities and alkali in the wastewater, which is beneficial to subsequent treatment; compared with directly adjusting the pH of the feed wastewater, the utilization rate of the alkali can be improved after enrichment and concentration of ammonia nitrogen, saving costs, and still ensuring a high mass transfer rate of ammonia.

[0067] 3) From the perspective of dynamics, compared with the existing Daonan dialysis and osmotic distillation coupling components, the tubular double-membrane ammonia nitrogen removal and recovery device of the present invention can improve the problems of low flux, large pressure loss and reduced power of the membrane process of the traditional coupling components, and can achieve more efficient turbulent flow, which helps to improve the mass transfer efficiency and the flux size of the membrane. In addition, the design of the integrated tubular membrane component does not require pipe connections, which can enhance the fluid dynamics effect, achieve higher water flow speed and pressure, increase the driving force of the membrane process, and significantly improve the membrane's separation performance for ammonia nitrogen and extend the service life of the membrane.

[0068] 4) From the perspective of process applicability, the tubular double-membrane ammonia nitrogen removal and recovery device of the present invention has a larger membrane surface area to volume ratio, and can accommodate more membrane area in a module of the same volume, thereby reducing the accumulation concentration of pollutants on a single membrane area. The present invention has the advantages of high integration (packing) density, strong processing capacity, small footprint, flexible series mode, simple operation and strong adaptability to application sites, etc. It can reduce the pollution and blockage problems caused by the formation of local high-concentration areas, and can be applied to the process combination application of multiple ports in sewage treatment plants. It has a wide range of applications and has broad development prospects in the overall technological innovation process of promoting sewage resource utilization.

[0069] 5) From the perspective of cleaning and maintenance, compared with traditional flat-plate components, the tubular double-membrane ammonia nitrogen removal and recovery device of the present invention allows the liquid to flow evenly and efficiently in the tube, has no dead corners, is not easy to scale, is not easy to clog, is easy to clean, does not require special cleaning agents, and has low cleaning and maintenance costs; the present invention has strong mechanical stability and the membrane components are not easy to be damaged.

[0070] 6) From the perspective of product recovery, the tubular double-membrane ammonia nitrogen removal and recovery device of the present invention can recover nitrogen from sewage through acid solution to obtain high-purity ammonium salt products. Compared with the existing recovery process, the economic benefit per ton of water can be increased by 3-6 times, and there is no secondary pollution. It is an environmentally friendly component and is consistent with the concept of sustainable development and the principle of circular economy.

[0071] 7) The tubular double-membrane ammonia nitrogen removal and recovery device of the present invention shows significant advantages in the recovery of ammonia nitrogen from wastewater, including simple operation, environmental friendliness, high efficiency and low consumption. In addition, the tubular component can be integrated with the electrochemical system to achieve reduced use of chemicals and improved ammonia nitrogen recovery efficiency. The tubular component is usually made of commercially available polyolefin materials (such as polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, etc.) and has good moisture resistance, thermal stability and chemical stability. In the future, tubular membrane technology is expected to develop further. By improving membrane materials, optimizing system design and improving energy efficiency, it can be widely used in wastewater treatment and resource recovery, and contribute to the realization of sustainable nitrogen cycle and environmental protection.

[0072] In addition, in the prior art for treating ammonia nitrogen wastewater, it is either based on concentration difference drive (i.e., natural concentration difference drive) or electric drive, and there is a lack of an ammonia nitrogen wastewater treatment device that effectively combines the two drive modes and has a reasonable structure. To solve this problem, in a preferred embodiment, an electric drive component is also included, and the electric drive component includes an anode metal mesh 13 and a cathode metal mesh 14, and the anode metal mesh 13 and the cathode metal mesh 14 are constructed as a tubular structure, and the anode metal mesh 13 is arranged between the housing 1 and the cation exchange membrane 2; the cathode metal mesh 14 is arranged between the cation exchange membrane 2 and the hollow fiber hydrophobic membrane 3; the anode metal mesh 13 is connected to the positive electrode of the power supply, and the cathode metal mesh 14 is connected to the negative electrode of the power supply. In the present invention, based on the three-cavity two-membrane structure (or, called a tubular double-membrane structure) design of the device of the present invention, the electric drive component can be easily and reasonably assembled into the coupling structure of the dialysis and osmotic distillation of the Donan, and no opposite interference or conflict will occur, which is unexpected according to the prior art. When the electric drive is operated and started, the overall device forms a structure of electrodialysis / -Donan dialysis composite drive and coupled with osmotic distillation, so that it can be effectively applied to the treatment of high-concentration ammonia nitrogen wastewater.

[0073] In this embodiment, when the anode metal mesh 13 and the cathode metal mesh 14 are powered on, the wastewater inlet chamber 4 is formed as an anode chamber, and the drive chamber 5 is formed as a cathode chamber. In the anode chamber, an oxygen evolution reaction occurs on the anode metal mesh 12, and water molecules lose electrons and are oxidized to generate oxygen and hydrogen ions. The chemical equation is as follows:

[0074] [2H2O(l)→O2(g)+4H + (aq)+4e - ]

[0075] In the cathode chamber, a hydrogen evolution reaction occurs on the cathode metal mesh 13, and water molecules are reduced by obtaining electrons to generate hydrogen and hydroxide ions. The chemical equation is as follows:

[0076] [2H2O(l)+2e - →H2(g)+2OH - (aq)]

[0077] In the present invention, first, ammonia nitrogen wastewater enters the anode chamber, and the ammonium ions contained therein enter the cathode chamber through the cation exchange membrane 2 under the drive of an external electric field; then the ammonium ions combine with the hydroxide ions generated by the cathode metal mesh 13 to generate free gaseous ammonia molecules, and the ammonia enters the recovery chamber 6 due to the difference in ammonia partial pressure between the cathode chamber and the recovery chamber 6; finally, the gaseous ammonia molecules combine with the hydrogen ions in the recovery chamber 6 to generate ammonium ions, which are then recovered in the form of liquid ammonium salts.

[0078] In the embodiment of the present invention, electric drive and concentration difference drive can be flexibly deployed. When treating high-concentration ammonia nitrogen wastewater, if the concentration difference drive effect is not ideal, it can be switched to electric drive to recover ammonia nitrogen.

[0079] Further, the anode metal mesh 13 is a titanium mesh coated with Ir mixed metal oxide, and / or the cathode metal mesh 14 is a stainless steel diamond grid.

[0080] After the device of the present invention is powered on, the recovery of ammonia nitrogen by electric drive has the following advantages:

[0081] 1) Higher ammonia mass transfer rate

[0082] After power is applied, the electric field-driven mechanism is used to enhance the mass transfer process of ammonia nitrogen. By applying an electric field, the ammonium ions (NH4 + ) undergo directional migration under the action of electric field force, which greatly accelerates the ammonia nitrogen ion (NH4 + ) through the cation exchange membrane (CEM). Therefore, the rapid migration of ions under the action of the electric field improves the removal rate of ammonia nitrogen and the overall efficiency of the system.

[0083] 2) Zero drug consumption in the drive room

[0084] After power is applied, the ammonia nitrogen removal mechanism with zero drug consumption can be realized in the driving chamber. When power is not applied, in order to drive the Daonan dialysis process, salt and alkali need to be added to the driving chamber, and after power is applied, the system can generate OH in the cathode chamber through electrochemical means. - This process avoids the consumption of chemicals and the OH produced by the cathode metal mesh. - Directly with NH4 + The reaction generates gaseous ammonia, which is then effectively removed and recovered through the subsequent steps of the system. Therefore, after power-on, the system has obvious advantages in reducing chemical consumption and improving environmental benefits.

[0085] 3) Adding electricity can reduce NH4 + Back diffusion

[0086] The free ammonia generated in the treatment process of the existing Donan dialysis osmotic distillation (DDOD) system is generated near the cation exchange membrane (CEM), and there is a certain distance between it and the hollow fiber hydrophobic membrane (GPM), resulting in the NH4 + It cannot be quickly converted into free ammonia, and thus accumulates on the left side of the CEM. When it accumulates to a certain extent, reverse diffusion will occur, which not only reduces the removal efficiency of ammonia nitrogen, but also may cause secondary pollution. In contrast, after power is applied, due to the direct effect of the electric field force, NH4 + Migrate to GPM faster and react with OH generated by the cathode metal mesh -Rapidly combine to generate NH3. In addition, the integrated intensive device design of the system after power-on greatly shortens the distance between the electrode and the GPM. This compact configuration significantly accelerates the mass transfer process of NH3, effectively avoiding the accumulation and reverse diffusion of ammonia, thereby improving the removal efficiency and stability of the entire system. This design not only optimizes the operating conditions, but also enhances the processing capacity of the system.

[0087] 4) Anode reaction degrades part of COD to alleviate membrane pollution

[0088] In the DDOD system, the organic matter in the wastewater mainly carries negatively charged functional groups, which tend to interact with the positively charged groups on the cation exchange membrane (CEM), resulting in reduced membrane flux and affecting the overall treatment efficiency. In contrast, the electric field force in the system after power-on can effectively attract these negatively charged organic molecules and move them toward the anode metal mesh, thereby avoiding adverse binding with the CEM and significantly reducing the risk of membrane fouling. In addition, the oxidation reaction of the anode metal mesh in the powered system and the strong oxidizing substances it produces can degrade part of the chemical oxygen demand (COD), which not only effectively avoids membrane fouling, but also improves the biological / chemical oxygen demand ratio (B / C ratio) of the effluent, enhancing the effect of subsequent biological treatment.

[0089] 5) Adjust voltage and current, the device is flexible to operate and has strong adaptability

[0090] By adjusting the voltage and current, the system can adapt to the changing working conditions and optimize the removal and recovery efficiency of ammonia nitrogen. This adjustment capability not only allows the system to flexibly adjust the operating parameters according to the concentration changes of ammonia nitrogen in the wastewater, but also allows the operator to accurately control the ion migration during the reaction process according to the specific treatment goals and environmental conditions, thereby achieving efficient removal of ammonia nitrogen. In addition, the adjustment of voltage and current also provides the system with the ability to cope with changes in different water quality and water volume, allowing the system to maintain optimal treatment performance under various environmental conditions.

[0091] like Figure 8As shown, in a preferred embodiment, the wastewater inlet chamber 4 is provided with a spiral inlet gallery 15 for receiving the input of the ammonia nitrogen wastewater to be treated, and the spiral inlet gallery 15 is formed by spirally winding from top to bottom along the outer side of the cation exchange membrane 2. The spiral inlet gallery 15 extends the inflow path of the ammonia nitrogen wastewater to be treated, increases the contact time with the cation exchange membrane 2, and improves the mass transfer efficiency and the deammoniation efficiency; and the spiral flow field formed can enhance the turbulent flow and reduce the concentration polarization phenomenon occurring on the surface of the cation exchange membrane 2; and the spiral water inlet can also increase the tangential flow velocity of the water flow, has a flushing effect on the cation exchange membrane 2, and reduces the deposition of pollutants on the surface of the cation exchange membrane 2; in addition, the spiral inlet gallery 15 can also make the ammonia nitrogen wastewater flow more evenly through the surface of the cation exchange membrane 2, reduce the formation of local high concentration areas, thereby reducing the risk of contamination of the cation exchange membrane 2 and extending the service life of the cation exchange membrane 2.

[0092] Among them, a smaller spiral angle can maintain the stability of the flow of ammonia nitrogen wastewater, while a larger spiral angle can increase the tangential velocity of the fluid, thereby enhancing the shear force and achieving the flushing of pollutants on the surface of the cation exchange membrane 2. Preferably, the spiral angle of the spiral water inlet gallery 15 is 15°~25°; and the angle between the spiral water inlet gallery 15 and the cation exchange membrane 2 is 45°, which can form an impact force in the tangential direction, have a flushing effect on the cation exchange membrane 2, and prevent the cation exchange membrane 2 from being contaminated.

[0093] like Figure 1 and Figure 2 As shown, in a preferred embodiment, a mesh support member 16 is provided on the outside and / or inside of the cation exchange membrane 2. The provided mesh support member 16 can evenly disperse the pressure impact on the cation exchange membrane 2 caused by the inflow of the ammonia nitrogen wastewater to be treated, effectively avoiding the risk of damage to the surface of the cation exchange membrane 2 due to excessive pressure locally; and the geometric configuration of the mesh support member 16 reduces the pressure drop in the flow channel and reduces energy consumption; and can also increase additional mechanical strength, which helps to maintain the stability of the system when facing fluid pressure fluctuations. Among them, the thickness of the mesh support member 16 is preferably 1 to 3 mm.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A tubular double membrane ammonia nitrogen removal and recovery device, characterized in that: include: A housing (1) having a hollow interior; A cation exchange membrane (2) which is a tubular structure and is disposed in the hollow inner cavity of the housing (1); A hollow fiber hydrophobic membrane (3) which is a tubular structure and is disposed in the inner cavity of the cation exchange membrane (2); A wastewater inlet chamber (4) is formed between the housing (1) and the cation exchange membrane (2); a driving chamber (5) is formed between the cation exchange membrane (2) and the hollow fiber hydrophobic membrane (3); and a recovery chamber (6) is formed inside the hollow fiber hydrophobic membrane (3); The wastewater inlet chamber (4) is configured to receive input of ammonia nitrogen wastewater to be treated, the drive chamber (5) is configured to receive input of external drive liquid, and the recovery chamber (6) is configured to receive input of external acid liquid and output ammonium salt to the outside; The hollow fiber hydrophobic membrane (3) comprises a plurality of closely arranged bundled hollow membrane fibers (7), and a control device capable of adjusting the opening and closing degree of the acid liquid inlet is provided corresponding to the acid liquid inlet of the hollow fiber hydrophobic membrane (3), so that the number of membrane fibers in all bundled hollow membrane fibers (7) that participate in the acid liquid contact work can be adjusted.

2. The tubular double-membrane ammonia nitrogen removal and recovery device according to claim 1, characterized in that: The control device is configured to determine the degree of opening and closing of the acid solution inlet of the hollow fiber hydrophobic membrane (3) based on the concentration of the ammonia nitrogen wastewater to be treated.

3. The tubular double-membrane ammonia nitrogen removal and recovery device according to claim 2, characterized in that: The regulating device comprises a paddle (8), a chassis (9) and a plurality of opening and closing blades (10), wherein the paddle (8) and the chassis (9) are respectively provided with sliding grooves, wherein the sliding grooves of the paddle (8) and the chassis (9) form a certain angle in space, wherein a sliding column (11) is provided on the opening and closing blades (10), wherein the sliding column (11) is positioned in the sliding groove, wherein the chassis (9) can be driven to rotate, wherein the sliding column (11) slides in the sliding groove by the rotation of the chassis (9), wherein the opening and closing blades (10) are moved closer to and farther from a center position by means of the repeated sliding of the sliding column (11) in the sliding groove, thereby adjusting the opening and closing range of the regulating device.

4. The tubular double-membrane ammonia nitrogen removal and recovery device according to claim 3 is characterized in that: The number of the slide grooves provided on the paddle (8), the slide grooves provided on the chassis (9) and the slide posts (11) provided on the opening and closing blades (10) corresponds one to one.

5. The tubular double-membrane ammonia nitrogen removal and recovery device according to claim 4, characterized in that: An acid distributor (12) is arranged above the regulating device, and the acid distributor (12) inputs external acid liquid into the bundled hollow membrane fibers (7) of the hollow fiber hydrophobic membrane (3) through the opening and closing port of the regulating device.

6. The tubular double-membrane ammonia nitrogen removal and recovery device according to any one of claims 1 to 5, characterized in that: Also included is an electric drive assembly, the electric drive assembly comprising: an anode metal mesh (13) which is constructed as a tubular structure and is arranged between the housing (1) and the cation exchange membrane (2); A cathode metal mesh (14) is constructed as a tubular structure and is arranged between the cation exchange membrane (2) and the hollow fiber hydrophobic membrane (3); The anode metal mesh (13) is connected to the positive pole of the power supply, and the cathode metal mesh (14) is connected to the negative pole of the power supply. When the anode metal mesh and the cathode metal mesh are powered on and working, the wastewater inlet chamber is formed into an anode chamber, and the drive chamber can be formed into a cathode chamber.

7. The tubular double-membrane ammonia nitrogen removal and recovery device according to claim 6, characterized in that: The anode metal mesh (13) is a titanium mesh coated with Ir mixed metal oxide, and / or the cathode metal mesh (14) is a stainless steel diamond grid.

8. The tubular double-membrane ammonia nitrogen removal and recovery device according to claim 6, characterized in that: The wastewater inlet chamber (4) is provided with a spiral inlet gallery (15) for receiving the input of ammonia nitrogen wastewater to be treated, and the spiral inlet gallery (15) is formed by spirally winding from top to bottom along the outer side of the cation exchange membrane (2).

9. The tubular double-membrane ammonia nitrogen removal and recovery device according to claim 8, characterized in that: The spiral angle of the spiral water inlet gallery (15) is 15° to 25°, and the angle between the spiral water inlet gallery (15) and the cation exchange membrane (2) is 45°.

10. The tubular double-membrane ammonia nitrogen removal and recovery device according to claim 6, characterized in that: A mesh support member (16) is provided on the outer side and / or the inner side of the cation exchange membrane (2).

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