Sewage treatment device with nested composite membrane component

Abstract

The invention relates to a sewage treatment device with nested composite membrane modules, the sewage treatment device comprises a tank body and a plurality of membrane modules in the tank body, the membrane modules are circular ring-shaped and comprise a plurality of layers of membrane module rings, and the membrane module rings comprise top support plates and bottom support plates; the membrane group ring piece is divided into a vertical type, an inclined type and a combined type; each of the vertical membrane group ring piece, the inclined membrane group ring piece and the composite membrane group ring piece comprises a plurality of layers of membrane wire groups which are sequentially arranged from outside to inside, and each circle of membrane wire group comprises a plurality of membrane wires; the top ends of membrane filaments of the vertical membrane group ring piece and the inclined membrane group ring piece are connected with a top supporting plate, and the bottom ends are communicated with an air supply pipe on a bottom supporting plate; membrane wires of the vertical membrane group ring piece are vertical; membrane filaments of the inclined membrane group ring piece are inclined, and the inclination directions of two adjacent circles of membrane filaments inside and outside are opposite. Each membrane wire group of the composite membrane group ring piece further comprises a round load net rack, membrane wires of each membrane wire group are encircled into a horizontal circle along the load net rack, and the membrane wires of the same circle of membrane wire group are uniformly distributed between the top supporting plate and the bottom supporting plate from top to bottom.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a sewage treatment device with a nested composite membrane component. Background Art

[0002] Membrane components can be used as good microbial carriers in the field of sewage treatment. The membrane material has a large specific surface area, many pores, and is water-permeable and / or breathable. It can carry a large number of microorganisms and provide oxygen for microorganisms. The process of sewage contacting the surface of the membrane material is the process of pollutants contacting microorganisms, which can be fully biochemically treated. In practical applications, in order to increase biomass, the simplest method is usually to increase the volume of the membrane component and increase the area of ​​the membrane material at the same time. If the volume of the membrane component is too large, the cost of installation, operation, and maintenance of the component will increase. There are also applications in which the size of the membrane component is not increased, but the membrane area is increased, resulting in too much membrane area per unit water area, resulting in insufficient microbial nutrients, and the inability to form a large number of biofilms, which reduces the utilization rate of the membrane material. Summary of the invention

[0003] In view of the above problems, the present invention provides a sewage treatment device with a nested composite membrane assembly, comprising a tank body and a plurality of membrane assemblies inside the tank body, wherein the membrane assembly is a nested structure and comprises a plurality of membrane assembly rings from the outside to the inside, wherein the membrane assembly rings are in a circular shape as a whole, and the diameter of the membrane assembly rings gradually decreases from the outside to the inside, and the membrane assembly rings comprise a top support plate and a bottom support plate; the membrane assembly rings are divided into three types, namely vertical, inclined and composite; the vertical membrane assembly rings, the inclined membrane assembly rings and the composite membrane assembly rings all comprise a plurality of membrane wire groups arranged in sequence from the outside to the inside, and each membrane wire group comprises a plurality of membrane wires;

[0004] The membrane wires of the same circle of the vertical membrane assembly ring and the inclined membrane assembly ring are parallel to each other, the top of the membrane wire is connected to the top support plate, and the bottom of the membrane wire is connected to the air supply pipe on the bottom support plate to supply air to the membrane wire; the membrane wires of the vertical membrane assembly ring are all vertical, and the membrane wires of the inclined membrane assembly ring are all inclined, and the inclined directions of the two adjacent circles of the inclined membrane assembly ring are opposite;

[0005] The membrane wire group of the composite membrane group ring also includes a circular load grid, and the membrane wires are all surrounded by the load grid to form a horizontal circle. The membrane wires of the same circle of membrane wire group are evenly distributed between the top support plate and the bottom support plate from top to bottom.

[0006] The present invention designs a new membrane assembly, completely abandoning the limitations of traditional cubic membrane assemblies, and designs a cylindrical inner and outer nested membrane assembly, which can be flexibly split, and the inner and outer membrane assembly rings do not interfere with each other and can rotate independently. The whole set of membrane assemblies has three types of membrane assembly rings, and the placement of membrane wires is different. When the membrane assembly rings rotate, a richer water flow form will be formed between the inner and outer membrane assembly rings, promoting sewage to enter the inner membrane assembly ring.

[0007] Optionally, the top supporting plate and the bottom supporting plate of the same membrane assembly ring are concentrically arranged, correspond to each other up and down, and have the same diameter.

[0008] Optionally, the vertical membrane group ring member includes a plurality of first docking grooves, a plurality of first docking rings, a plurality of first air supply pipes and a first main air pipe, the plurality of first docking grooves are all circular and concentrically arranged, the plurality of first docking grooves are evenly arranged on the lower surface of the top support plate of the vertical membrane group ring member, and are concave upward; the plurality of first docking rings are all circular and concentrically arranged, the first docking rings can be embedded in the corresponding first docking grooves, so as to facilitate the disassembly and assembly of the membrane wires, and the top ends of the membrane wires of the same circle of the membrane wire group are closed and connected to the corresponding first docking rings;

[0009] Several first air supply pipes are circular and concentrically arranged. Several first air supply pipes are evenly arranged on the upper surface of the bottom support plate of the vertical membrane group ring. The bottom ends of the membrane wires of the same circle of membrane wire group are connected to the corresponding first air supply pipes; the first main air pipe penetrates each first air supply pipe along the radial direction of the bottom support plate.

[0010] Further optionally, the first main air pipe is arranged on the upper surface of the bottom support plate, both ends of the first air supply pipe are open and respectively connected to the two sides of the first main air pipe, one end of the first main air pipe close to the inside of the membrane group ring is closed, and the other end is connected to the external air supply device.

[0011] Optionally, the inclined membrane group ring member includes a plurality of second docking grooves, a plurality of second docking rings, a plurality of second air supply pipes and a second main air pipe, the plurality of second docking grooves are all circular and concentrically arranged, the plurality of second docking grooves are evenly arranged on the lower surface of the top supporting plate of the inclined membrane group ring member, and are concave upward; the plurality of second docking rings are all circular and concentrically arranged, the second docking rings can be embedded in the corresponding second docking grooves, so as to facilitate the disassembly and assembly of the membrane wires, and the top ends of the membrane wires of the same circle of membrane wire group are closed and connected to the corresponding second docking rings;

[0012] Several second air supply pipes are circular and concentrically arranged. Several second air supply pipes are evenly arranged on the upper surface of the bottom support plate of the vertical membrane group ring. The bottom ends of the membrane wires of the same circle of membrane wire group are connected to the corresponding second air supply pipes; the second main air pipe penetrates each second air supply pipe along the radial direction of the bottom support plate.

[0013] Further optionally, the second main air pipe is arranged on the upper surface of the bottom support plate, both ends of the second air supply pipe are open and respectively connected to the two sides of the second main air pipe, one end of the second main air pipe close to the inside of the membrane group ring is closed, and the other end is connected to the external air supply device.

[0014] Further optionally, the angle between the membrane wire of the inclined membrane group ring and the vertical line is 20°-45°.

[0015] Optionally, the composite membrane group ring comprises a plurality of third docking grooves, a plurality of fourth docking grooves, a plurality of third air supply pipes and a third main air pipe, the third docking grooves and the fourth docking grooves are both circular and concentrically arranged, the third docking grooves are evenly arranged on the lower surface of the top support plate of the composite membrane group ring and are recessed upward, the fourth docking grooves are evenly arranged on the upper surface of the bottom support plate of the composite membrane group ring and are recessed downward, and the top and bottom of the load grid of each membrane wire group are respectively clamped in the third docking groove and the fourth docking groove;

[0016] Several third air supply pipes are vertical and arranged along the radial direction of the composite membrane group ring. The top of the third air supply pipe is connected to the top support plate, and the bottom is connected to the third main air pipe on the bottom support plate; the third main air pipe is arranged along the radial direction of the bottom support plate.

[0017] Optionally, the load grid is woven from plastic wires that are staggered horizontally and vertically, and the sides of the load grid facing the membrane wires of the same circle of membrane wire group are evenly and densely covered with outwardly protruding piers, which are truncated cone-shaped with the center axis set horizontally, that is, the two circular sides of the pier heads are vertical.

[0018] Optionally, the membrane assembly is provided with vertical membrane assembly rings, inclined membrane assembly rings and composite membrane assembly rings in sequence from the outside to the inside, and the vertical, inclined and composite types are arranged in a cycle in sequence;

[0019] The top supporting plate of each membrane group ring is detachably connected to the corresponding motor above the water surface through a connecting rod. One motor corresponds to one membrane group ring, driving different membrane group rings to rotate at different speeds and directions.

[0020] Further optionally, the top supporting plate of each membrane group ring is detachably connected to the lifting device above the water surface through a connecting rod, and the upper and lower positions of the membrane group ring in the pool body are independently controlled to achieve flexible splitting of the membrane group ring of the same membrane assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the vertical membrane group ring;

[0022] Figure 2 It is a three-dimensional schematic diagram of a vertical membrane module ring;

[0023] Figure 3 It is a schematic diagram of the structure of the inclined membrane group ring;

[0024] Figure 4 It is a three-dimensional schematic diagram of the inclined membrane group ring;

[0025] Figure 5 Schematic diagram of the composite membrane group ring (the load grid is omitted);

[0026] Figure 6 Schematic diagram of the load grid.

[0027] In the accompanying drawings, 1-vertical membrane group ring, 2-inclined membrane group ring, 3-composite membrane group ring, 4-top support plate, 5-bottom support plate, 6-membrane wire, 7-third main air pipe, 8-load grid, 9-pier head, 10-fourth docking groove, 11-first docking ring, 12-second docking ring, 13-first air supply pipe, 14-second air supply pipe, 15-third air supply pipe, 16-first main air pipe, 17-second main air pipe. DETAILED DESCRIPTION

[0028] This embodiment provides a sewage treatment device having a nested composite membrane assembly, such as Figure 1-Figure 6 As shown, it includes a pool body and several membrane assemblies inside the pool body. The membrane assembly is a nested structure and includes several layers of membrane assembly rings from the outside to the inside. The membrane assembly ring is in a circular shape as a whole. The diameter of the membrane assembly ring gradually decreases from the outside to the inside. The membrane assembly ring includes a top support plate 4 and a bottom support plate 5. The membrane assembly rings are divided into three types, namely vertical, inclined and composite. The vertical membrane assembly ring 1, the inclined membrane assembly ring 2 and the composite membrane assembly ring 3 all include several layers of membrane wire groups arranged in sequence from the outside to the inside, and each circle of membrane wire groups includes several membrane wires 6.

[0029] The membrane threads of the same circle of the vertical membrane assembly ring 1 and the inclined membrane assembly ring 2 are parallel to each other, the top of the membrane thread is connected to the top support plate 4, and the bottom of the membrane thread is connected to the air supply pipe on the bottom support plate 5 to supply air to the membrane thread 6; the membrane threads of the vertical membrane assembly ring 1 are all vertical, and the membrane threads of the inclined membrane assembly ring 2 are all inclined, and the inclined directions of the two adjacent circles of the inclined membrane assembly ring 2 are opposite;

[0030] The membrane wire group of the composite membrane group ring 3 also includes a circular load grid 8, and its membrane wires 6 are all surrounded along the load grid 8 to form a horizontal circle. The membrane wires of the same circle of membrane wire group are evenly distributed between the top support plate 4 and the bottom support plate 5 from top to bottom.

[0031] Optionally, the top supporting plate 4 and the bottom supporting plate 5 are both in the shape of a circular ring, and the top supporting plate 4 and the bottom supporting plate 5 of the same membrane assembly ring are concentrically arranged, correspond to each other up and down, and have the same diameter.

[0032] Optionally, the vertical membrane group ring member 1 includes a plurality of first docking grooves, a plurality of first docking rings 11, a plurality of first air supply pipes 13 and a first main air pipe 16, the plurality of first docking grooves are all circular and concentrically arranged, the plurality of first docking grooves are evenly arranged on the lower surface of the top support plate 4 of the vertical membrane group ring member 1, and are concave upward; the plurality of first docking rings 11 are all circular and concentrically arranged, the first docking rings 11 can be embedded in the corresponding first docking grooves, so as to facilitate the disassembly and assembly of the membrane wire 6, and the top ends of the membrane wires 6 of the same circle of the membrane wire group are closed and connected to the corresponding first docking rings 11;

[0033] Several first air supply pipes 13 are circular and concentrically arranged. Several first air supply pipes 13 are evenly arranged on the upper surface of the bottom support plate 5 of the vertical membrane group ring 1. The bottom ends of the membrane wires 6 of the same circle of membrane wire group are connected to the corresponding first air supply pipes 13; the first main air pipe 16 penetrates each first air supply pipe 13 along the radial direction of the bottom support plate 5.

[0034] Further optionally, the diameters of the first docking grooves, the first docking rings 11 and the first air supply pipes 13 corresponding to the upper and lower parts are the same, serving to fix the membrane wires of the corresponding circle of membrane wire groups and supply air;

[0035] From outside to inside, the diameters of the first docking grooves, the first docking rings 11 and the first air supply pipes 13 gradually decrease.

[0036] Further optionally, the upper surface of the first air supply pipe 13 is provided with a plurality of docking holes, and the opening at the bottom end of the membrane thread 6 is inserted into the docking hole, so that the membrane thread 6 is connected with the corresponding first air supply pipe 13, and air can be supplied to the membrane thread.

[0037] Further optionally, the first main air pipe 16 is arranged on the upper surface of the bottom support plate 5, and both ends of the first air supply pipe 13 are open and respectively connected to the two sides of the first main air pipe 16, that is, the first main air pipe 16 is arranged around the bottom support plate 5, with one side of the first main air pipe 16 as the starting point and the other side as the end point. The first main air pipe 16 supplies air to both ends of the first air supply pipe 13 at the same time, thereby promoting a more uniform distribution of gas in the first air supply pipe 13; one end of the first main air pipe 16 close to the inside of the membrane group ring is closed, and the other end is connected to an external air supply device.

[0038] The vertical membrane group ring 1 has several layers of membrane wire groups arranged inside and outside, and the membrane wires 6 of each circle of membrane wire groups are vertical and evenly distributed along the circumference of the vertical membrane group ring 1. In the two adjacent circles of membrane wire groups inside and outside, along the radial direction of the vertical membrane group ring 1, the membrane wires of the inner circle correspond to the position between two adjacent membrane wires of the outer circle. This arrangement can make full use of the space, improve the density of membrane wires, and do not affect the flow of external sewage into and out of the vertical membrane group ring 1, thereby improving the bioload and membrane wire utilization.

[0039] Optionally, the inclined membrane group ring member 2 includes a plurality of second docking grooves, a plurality of second docking rings 12, a plurality of second air supply pipes 14 and a second main air pipe 17, the plurality of second docking grooves are all circular and concentrically arranged, the plurality of second docking grooves are evenly arranged on the lower surface of the top support plate 4 of the inclined membrane group ring member 2, and are concave upward; the plurality of second docking rings 12 are all circular and concentrically arranged, the second docking rings 12 can be embedded in the corresponding second docking grooves, which is convenient for disassembly and assembly of the membrane wire 6, and the top ends of the membrane wires of the same circle of membrane wire group are closed and connected to the corresponding second docking rings 12;

[0040] The plurality of second air supply pipes 14 are all circular and concentrically arranged, and are evenly arranged on the upper surface of the bottom support plate 5 of the vertical membrane group ring 1. The bottom ends of the membrane threads of the same circle of membrane thread group are connected to the corresponding second air supply pipes 14; the second main air pipe 17 penetrates each second air supply pipe 14 along the radial direction of the bottom support plate.

[0041] Further optionally, the diameters of the second docking grooves, the second docking rings 12 and the second air supply pipe 14 corresponding to the upper and lower parts are the same, serving to fix the membrane wires of the corresponding circle of the membrane wire group and supply air;

[0042] From outside to inside, the diameters of the plurality of second docking grooves, the plurality of second docking rings 12, and the plurality of second air supply pipes 14 gradually decrease.

[0043] Further optionally, the upper surface of the second air supply pipe 14 is provided with a plurality of docking holes, and the opening at the bottom end of the membrane thread 6 is inserted into the docking hole, so that the membrane thread 6 is connected with the corresponding second air supply pipe 14, and air can be supplied to the membrane thread.

[0044] Further optionally, the second main air pipe 17 is arranged on the upper surface of the bottom support plate 5, and both ends of the second air supply pipe 14 are open and respectively connected to the two sides of the second main air pipe 17, that is, the second main air pipe 17 is arranged around the bottom support plate 5, with one side of the second main air pipe 17 as the starting point and the other side as the end point. The second main air pipe 17 supplies air to both ends of the second air supply pipe 14 at the same time, thereby promoting a more uniform distribution of gas in the second air supply pipe 14; one end of the second main air pipe 17 close to the inside of the membrane group ring is closed, and the other end is connected to an external air supply device.

[0045] Further optionally, the angle between the membrane wire of the inclined membrane group ring 2 and the vertical line is 20°-45°.

[0046] The inclined membrane assembly ring 2 is also designed to have several layers of membrane wire groups arranged inside and outside. The membrane wires 6 of each circle of membrane wire groups are inclined and evenly distributed along the circumference of the inclined membrane assembly ring 2. The inclination directions of the two adjacent circles of membrane wires inside and outside are opposite. For example, the outer circle of membrane wires is inclined to the left from top to bottom, and the inner circle of membrane wires is inclined to the right from top to bottom. Compared with the vertical membrane wires, although the number of membrane wires is reduced when the membrane wires are inclined, the inclined membrane wires can change the single form of water flow formed by the vertical membrane wires, especially the design of the opposite inclination directions of the two adjacent circles of membrane wires inside and outside, which has a stronger ability to disturb the water flow and promote the sewage outside the membrane assembly to flow inside. Moreover, after the inclined membrane assembly ring 2 has been in operation for a long time, the dead microorganisms cover the outside of the active biofilm. Under the action of hydraulic shear force, the inclined membrane wires make it easier for the dead biofilm to fall off.

[0047] Optionally, the composite membrane group ring member 3 includes a plurality of third docking grooves, a plurality of fourth docking grooves 10, a plurality of third air supply pipes 15 and a third main air pipe 7, the third docking grooves and the fourth docking grooves 10 are circular and concentrically arranged, the third docking grooves are evenly arranged on the lower surface of the top support plate 4 of the composite membrane group ring member 3, and are concave upward, the fourth docking grooves 10 are evenly arranged on the upper surface of the bottom support plate 5 of the composite membrane group ring member 3, and are concave downward, and the top and bottom of the load grid 8 of each membrane wire group are respectively clamped in the third docking groove and the fourth docking groove 10;

[0048] Several third air supply pipes 15 are vertical and arranged along the radial direction of the composite membrane group ring 3. The top of the third air supply pipe 15 is connected to the top support plate 4, and the bottom is connected to the third main air pipe 7 on the bottom support plate 5; the third main air pipe 7 is arranged along the radial direction of the bottom support plate 5.

[0049] Further optionally, the diameters of the upper and lower corresponding third docking grooves, the load grid 8 and the fourth docking groove 10 are the same, and the membrane wires of the membrane wire group of the corresponding circle are fixed;

[0050] From outside to inside, the diameters of the plurality of third docking grooves, the plurality of fourth docking grooves 10 and the plurality of load grids 8 gradually decrease.

[0051] Further optionally, the top of the third air supply pipe 15 is closed, and a number of docking holes are respectively provided on both sides. The openings at both ends of the membrane thread 6 are respectively inserted into the docking holes on both sides of the third air supply pipe 15, so that the membrane thread 6 is connected with the corresponding third air supply pipe 15, and can supply air to the membrane thread. That is, the membrane thread is arranged in a circle along the load grid 8, with one side of the corresponding third air supply pipe 15 as the starting point and the other side as the end point. The third air supply pipe 15 supplies air to both ends of the membrane thread at the same time, thereby promoting a more uniform distribution of gas in the membrane thread.

[0052] Further optionally, one end of the third main air pipe 7 close to the inside of the membrane assembly ring is closed, and the other end is connected to an external air supply device.

[0053] Optionally, the load grid 8 is woven from plastic wires that are staggered horizontally and vertically, and the sides of the load grid 8 facing the membrane wires of the same circle of membrane wire group are evenly and densely covered with outwardly protruding pier heads 9. The pier heads 9 are truncated cone-shaped, and the center axis is horizontally set, that is, the two circular sides of the pier heads 9 are both vertical.

[0054] The composite membrane group ring 3 also has several layers of membrane wire groups arranged inside and outside, and the membrane wires 6 of each circle of membrane wire groups are horizontal and evenly distributed along the length direction of the third air supply pipe 15. The membrane wires 6 are supported by the load grid 8 of the same circle to form a circle, and some parts of the membrane wires may contact the circular top surface of the pier 9 (at this time, the circular surface is at the outermost side of the load grid 8), and some parts may be between two piers 9. The above situation can leave a certain gap between some parts of the membrane wire and the load grid 8, allowing the part of the membrane wire and the load grid 8 to contact the sewage, improving the carrier utilization rate, and can also make some parts of the membrane wire limited by the pier 9 to maintain the relative position of the membrane wire and the load grid 8, and at the same time, with the help of the buoyancy of the sewage, the membrane wire can be kept horizontal.

[0055] Traditional membrane filaments are arranged vertically, which is convenient for positioning and installation, and is not easy to get entangled with each other during operation. The inventor unexpectedly found that the transverse membrane filaments combined with the longitudinal membrane filaments can promote the change of the sewage flow form, promote the full contact between microorganisms and sewage, and increase the installation density of the membrane filaments, which is conducive to maintaining the sewage treatment efficiency. The problems existing in the positioning, installation and operation of the transverse membrane filaments can be solved by setting a load grid 8.

[0056] Optionally, the membrane assembly is provided with a vertical membrane assembly ring 1, an inclined membrane assembly ring 2 and a composite membrane assembly ring 3 in sequence from the outside to the inside, and the vertical, inclined and composite types are arranged in a cycle in sequence;

[0057] The top supporting plate of each membrane group ring is detachably connected to the corresponding motor above the water surface through a connecting rod. One motor corresponds to one membrane group ring, driving different membrane group rings to rotate at different speeds and directions.

[0058] As a specific implementation method, in the membrane assembly, the motor corresponding to the inner membrane ring is positioned lower, which does not affect the upper motor controlling the rotation of the outer membrane ring; the inner and outer rings of different membrane rings rotate at different speeds and / or directions, which is conducive to the sewage entering the interior of the membrane assembly, and combined with the arrangement of the membrane filaments of the different forms of internal membrane rings, the water micro-flow is richer and more multi-dimensional, which promotes the contact between the sewage and the microorganisms on the membrane filaments.

[0059] Further optionally, the top supporting plate of each membrane group ring is detachably connected to the lifting device above the water surface through a connecting rod, and the upper and lower positions of the membrane group ring in the pool body are independently controlled to achieve flexible splitting of the membrane group ring of the same membrane assembly.

[0060] As a specific implementation, in the membrane assembly, when a certain membrane assembly ring needs to be lifted or lowered, the connecting rod and the motor are removed and connected to the lifting device to independently control the lifting or lowering of the membrane assembly ring.

[0061] After the membrane assembly has been running for a long time, the biofilm on the surface of the membrane wire ages and dies, and the aging biofilm of the membrane wire inside the membrane assembly is more difficult to fall off than the external membrane wire. Each membrane assembly ring of the present invention can be flexibly raised and lowered. For example, the membrane assembly ring inside the membrane assembly moves downward, and the pool body is provided with an aeration pipe, and the aeration effect promotes the shedding of the aging biofilm of the membrane assembly ring. On the other hand, each membrane assembly ring can be raised and lowered, which can temporarily improve the water environment where the membrane assembly ring is located and promote the healthy metabolism of the biofilm thereon.

[0062] The material of the membrane fiber of the present invention is determined according to the requirements of sewage treatment, for example, heavy ion microporous membrane, PVDF hollow fiber membrane, PDMS hollow fiber membrane can be used.

Claims

1. A sewage treatment device having a nested composite membrane assembly, characterized in that: The invention comprises a pool body and several membrane modules inside the pool body. The membrane modules are of a nested structure and include several layers of membrane group rings from the outside to the inside. The membrane group rings are in a circular shape as a whole. The diameter of the membrane group rings gradually decreases from the outside to the inside. The membrane group rings include a top support plate and a bottom support plate. The membrane group rings are divided into three types, namely vertical, inclined and composite. The vertical membrane group rings, the inclined membrane group rings and the composite membrane group rings all include several layers of membrane wire groups arranged in sequence from the outside to the inside, and each circle of membrane wire groups includes several membrane wires. The membrane wires of the same circle of the vertical membrane assembly ring and the inclined membrane assembly ring are parallel to each other, the top of the membrane wire is connected to the top support plate, and the bottom of the membrane wire is connected to the air supply pipe on the bottom support plate to supply air to the membrane wire; the membrane wires of the vertical membrane assembly ring are all vertical, and the membrane wires of the inclined membrane assembly ring are all inclined, and the inclined directions of the two adjacent circles of the inclined membrane assembly ring are opposite; The membrane wire group of the composite membrane group ring also includes a circular load grid, and the membrane wires are all surrounded by the load grid to form a horizontal circle. The membrane wires of the same circle of membrane wire group are evenly distributed between the top support plate and the bottom support plate from top to bottom.

2. The sewage treatment device with nested composite membrane modules according to claim 1, characterized in that: The top supporting plate and the bottom supporting plate of the same membrane group ring are concentrically arranged, correspond to each other up and down, and have the same diameter.

3. The sewage treatment device with nested composite membrane modules according to claim 2, characterized in that: The vertical membrane assembly ring member includes a plurality of first docking grooves, a plurality of first docking rings, a plurality of first air supply pipes and a first main air pipe, the plurality of first docking grooves are all circular and concentrically arranged, and the plurality of first docking grooves are evenly arranged on the lower surface of the top supporting plate of the vertical membrane assembly ring member and are concave upwards; The first docking rings are all circular and concentrically arranged, and can be embedded in the corresponding first docking grooves to facilitate the disassembly and assembly of the membrane wires. The top ends of the membrane wires of the same circle of membrane wire group are closed and connected to the corresponding first docking rings; Several first air supply pipes are circular and concentrically arranged. Several first air supply pipes are evenly arranged on the upper surface of the bottom support plate of the vertical membrane group ring. The bottom ends of the membrane wires of the same circle of membrane wire group are connected to the corresponding first air supply pipes; the first main air pipe penetrates each first air supply pipe along the radial direction of the bottom support plate.

4. The sewage treatment device with nested composite membrane modules according to claim 3, characterized in that: The first main air pipe is arranged on the upper surface of the bottom support plate, both ends of the first air supply pipe are open and respectively connected to the two sides of the first main air pipe, one end of the first main air pipe close to the inside of the membrane group ring is closed, and the other end is connected to the external air supply device.

5. The sewage treatment device with nested composite membrane modules according to claim 2, characterized in that: The inclined membrane assembly ring member includes a plurality of second docking grooves, a plurality of second docking rings, a plurality of second air supply pipes and a second main air pipe, the plurality of second docking grooves are all circular and concentrically arranged, and the plurality of second docking grooves are evenly arranged on the lower surface of the top supporting plate of the inclined membrane assembly ring member and are concave upwards; The plurality of second docking rings are all circular and concentrically arranged, and the second docking rings can be embedded in the corresponding second docking grooves, so as to facilitate the disassembly and assembly of the membrane wires. The top ends of the membrane wires of the same circle of membrane wire group are closed and connected to the corresponding second docking rings; Several second air supply pipes are circular and concentrically arranged. Several second air supply pipes are evenly arranged on the upper surface of the bottom support plate of the vertical membrane group ring. The bottom ends of the membrane wires of the same circle of membrane wire group are connected to the corresponding second air supply pipes; the second main air pipe penetrates each second air supply pipe along the radial direction of the bottom support plate.

6. The sewage treatment device with nested composite membrane modules according to claim 5, characterized in that: The second main air pipe is arranged on the upper surface of the bottom support plate, both ends of the second air supply pipe are open and respectively connected to the two sides of the second main air pipe, one end of the second main air pipe close to the inside of the membrane group ring is closed, and the other end is connected to the external air supply device; The included angle between the membrane wire of the inclined membrane group ring and the vertical line is 20°-45°.

7. The sewage treatment device with nested composite membrane modules according to claim 2, characterized in that: The composite membrane assembly ring comprises a plurality of third docking grooves, a plurality of fourth docking grooves, a plurality of third air supply pipes and a third main air pipe. The third docking grooves and the fourth docking grooves are both circular and concentrically arranged. The third docking grooves are evenly arranged on the lower surface of the top supporting plate of the composite membrane assembly ring and are concave upward. The fourth docking grooves are evenly arranged on the upper surface of the bottom supporting plate of the composite membrane assembly ring and are concave downward. The top and bottom of the load grid of each membrane wire group are respectively clamped in the third docking groove and the fourth docking groove. Several third air supply pipes are vertical and arranged along the radial direction of the composite membrane group ring. The top of the third air supply pipe is connected to the top support plate, and the bottom is connected to the third main air pipe on the bottom support plate; the third main air pipe is arranged along the radial direction of the bottom support plate.

8. The sewage treatment device with nested composite membrane modules according to claim 7, characterized in that: The load grid is woven from plastic wires that are staggered horizontally and vertically. The sides of the load grid facing the membrane wires of the same circle of membrane wire group are evenly and densely covered with outwardly protruding piers. The piers are truncated cone-shaped and the central axis is horizontally arranged, that is, the two circular sides of the piers are both vertical.

9. The sewage treatment device with nested composite membrane modules according to claim 1, characterized in that: The membrane assembly is provided with vertical membrane assembly rings, inclined membrane assembly rings and composite membrane assembly rings in sequence from the outside to the inside, and the vertical, inclined and composite membrane assembly rings are arranged in sequence in a cycle; The top supporting plate of each membrane group ring is detachably connected to the corresponding motor above the water surface through a connecting rod. One motor corresponds to one membrane group ring, driving different membrane group rings to rotate at different speeds and directions.

10. The sewage treatment device with nested composite membrane modules according to claim 1, characterized in that: The top supporting plate of each membrane group ring is detachably connected to the lifting device above the water surface through a connecting rod, and the upper and lower positions of the membrane group ring in the pool body are independently controlled to realize the flexible splitting of the membrane group ring of the same membrane assembly.

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