Moving bed biofilm reaction device and preparation method of curved surface filler

Abstract

The invention discloses a moving bed biofilm reaction device and a preparation method of a curved surface filler, an existing filler structure is optimally designed based on a triple minimal curved surface bionic structure, a microporous minimal curved surface filler is manufactured by utilizing a 3D printing technology, the adhesion amount of a biofilm per unit area is remarkably increased, and the biofilm reaction device has the advantages that the biofilm reaction device is simple in structure and convenient to operate; due to the structural complexity, the biological membrane can be prevented from being influenced by fluid shear force, and due to the fact that the flow states of all the surfaces are different, the development of the unique heterogeneous biological membrane can be stimulated; meanwhile, the MBBR structure is optimally designed, the space utilization efficiency of equipment is improved, and a separation layer is designed in the aerobic zone, so that vortexes are generated in the aerobic zone, the hydraulic retention time of the filler is prolonged, and filler biological membrane supplementation and efficient sewage treatment are realized.

Description

Technical Field

[0001] The present invention belongs to the field of sewage treatment, and specifically relates to a moving bed biofilm reactor device and a preparation method of curved fillers. Background Art

[0002] The moving bed biofilm reactor (MBBR) is an innovative sewage treatment technology that ingeniously combines the advantages of the activated sludge process (suspended-growth microorganisms) and the biofilm process (attached-growth microorganisms). This technology originated in the mid-1980s, and its core lies in using lightweight fillers (with a density close to that of water and capable of suspending in the aeration tank) as the attachment matrix for microorganisms. Through aeration, the fillers remain in a flowing state and are fully mixed with the sewage, enabling microorganisms to grow in a three-phase environment of gas, liquid, and solid. In this environment, anaerobic or facultative anaerobic bacteria inside the fillers can multiply in large numbers, while aerobic bacteria occupy the outside. Each filler particle is equivalent to a miniature bioreactor, enabling the nitrification and denitrification processes to occur simultaneously.

[0003] In the existing moving bed biofilm reactor (MBBR) technology, the filler structure usually adopts simple geometric shapes, such as hollow spheres or annular structures. Although it can provide a certain amount of space for microbial attachment, its specific surface area is insufficient, resulting in a limited amount of biofilm attachment per unit volume and making it difficult to meet the requirements of high-load sewage treatment. In addition, traditional fillers are easily damaged by fluid shear force under high-flow-rate conditions, leading to the shedding of biofilms and poor stability, and unable to effectively maintain long-term operation. At the same time, the existing MBBR device has a short hydraulic retention time in the aerobic zone and uneven water flow distribution, resulting in low filler utilization rate and low biofilm replenishment efficiency, further reducing the sewage treatment effect.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a moving bed biofilm reactor device and a preparation method of curved fillers, solving the problems raised in the above background art.

[0006] To solve the above technical problems, the basic concept of the technical solution adopted by the present invention is: A moving bed biofilm reactor device includes: an anaerobic tank, an anoxic tank, an aerobic tank, a drainage tank, and curved fillers moving in the anoxic tank and the aerobic tank. A water inlet is provided on the first side at the upper end of the anaerobic tank, and a communication port A connected to the anoxic tank is provided on the second side. On one side of the bottom of the anoxic tank away from the anaerobic tank, a circulation port B is provided, and the anoxic tank and the aerobic tank are connected through the circulation port B; above the aerobic tank, a vortex plate separation layer for extending the hydraulic retention time of the curved surface packing is provided, and above the vortex plate separation layer, a packing circulation loop is connected. The packing circulation loop is connected to the anoxic tank, and a circulation pump is arranged in the packing circulation loop to form a reflux of the curved surface packing with the anoxic tank. On one side of the bottom of the aerobic tank away from the anoxic tank, a drain port is provided. The aerobic tank is connected to the drain tank through the drain port. A switchable screen is arranged in the drain port to control the discharge of the treated sewage and filter the curved surface packing. On one side of the drain tank away from the aerobic tank, a water outlet for discharging the treated sewage is provided.

[0007] Optionally, an anoxic aeration pump and an anaerobic aeration pump are respectively arranged at the bottoms of the anaerobic tank and the anoxic tank. At the bottom of the aerobic tank, an aerobic aeration pump A and an aerobic aeration pump B are arranged in sequence from left to right. Among them, the aeration direction of the aerobic aeration pump B is directly below the inlet of the vortex plate separation layer, and the anaerobic aeration pump is located below the packing circulation loop.

[0008] Optionally, the vortex plate separation layer is located at the 1 / 2 position above the aerobic tank. The vortex plate separation layer is composed of a number of vortex plates arranged from top to bottom. Among them, the gap between every two adjacent vortex plates is 2 to 4 times the diameter of the curved surface packing.

[0009] Optionally, the switchable screen is composed of a screen and a baffle. Among them, the baffle is rotatably connected to one side of the screen, and after rotation, the baffle is located in the drain tank. Specifically, the baffle can be rotated by means of a waterproof motor.

[0010] A preparation method of a curved surface packing, the curved surface packing is applicable to the above-mentioned moving bed biofilm reactor, serves as a carrier for microorganism attachment and optimizes the hydraulic characteristics of sewage treatment. The preparation method includes the following steps: Substitute the minimal surface formula into the Mathematica software to obtain its 3D modeling model; Mix commercial photosensitive resin and porogenic agent polyethylene glycol in a predetermined ratio and stir evenly as the raw material for 3D printing; Input the 3D modeling file designed above into the slicing software of the 3D printer for slicing processing. Then import the sliced file into the 3D printer, inject the photosensitive resin mixture into the printing tank, and start the 3D printer to print the configuration; After printing, wash the printed curved surface packing with a solvent multiple times to remove surface residues, and then place the curved surface packing in an ultraviolet curing device for secondary curing, thereby completing the preparation of the curved surface packing.

[0011] Optionally, the polyethylene glycol is one of low-polymerization PEG-200, PEG-400 and high-polymerization PEG-2000, PEG-4000, and the photocurable resin is richopto 306 type LCD water-washable photosensitive resin.

[0012] Optionally, the raw materials for 3D printing photocuring, the commercial photosensitive resin and the pore-forming agent polyethylene glycol, are mixed in a ratio of 6-9:4-1.

[0013] Optionally, when substituting into Mathematica software to obtain the implicit function expression of the surface structure in its 3D modeling model: Sin[x]Cos[y]+Sin[y]Cos[z]+Sin[z]Cos[x]=C, {x, -r, r}, {y, -r, r}, {z, -r, r}, where x, y, and z are the three coordinates of the coordinate system, r is the radius, and C is the threshold; by adjusting the size of r, the pore size and density of the surface filler are realized, and by adjusting C, the wall thickness of the filler is controlled.

[0014] Optionally, the 3D printing parameters are set as follows: layer thickness 0.05-0.1 mm, exposure time 2-5 s, bottom exposure time 30-60 s, and bottom number of layers 3-8 layers.

[0015] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art. Of course, any product implementing the present invention does not necessarily need to achieve all the advantages described below at the same time: The present invention optimizes the design of the existing filler structure based on the bionic structure of the triple minimal surface, uses 3D printing technology to produce a microporous minimal surface filler, significantly increases the biofilm attachment amount per unit area, and its structural complexity can protect the biofilm from the influence of fluid shear force. And because the flow states of each surface are different, this can stimulate the development of unique heterogeneous biofilms; at the same time, the present invention optimizes the design of the MBBR structure, improves the space utilization efficiency of the device, designs a separation layer in the aerobic zone, makes vortices generated in this area, increases the hydraulic retention time of the filler, and thereby realizes the replenishment of the filler biofilm and efficient sewage treatment. The MBBR device using the minimal surface filler proposed by the present invention can not only improve the biofilm load and reasonable distribution, but also save the floor area of the device and achieve more effective sewage treatment.

[0016] The following further describes in detail the specific embodiments of the present invention with reference to the accompanying drawings. Description of the Drawings

[0017] The following drawings in the description are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts. In the drawings: Figure 1 Schematic structural diagram of the filler in the present invention; Figure 2 Schematic side view of the moving bed biofilm reactor in the present invention.

[0018] In the attached drawings, the components represented by each reference numeral are as follows: 1. Filler; 21. Water inlet; 22. Anaerobic tank; 23. Anoxic tank; 24. Aerobic tank; 25. Water outlet; 26. Anoxic aeration pump; 27. Anaerobic aeration pump; 28. Aerobic aeration pump A; 29. Aerobic aeration pump B; 210. Vortex plate separation layer; 211. Circulation pump; 212. Switchable screen; 213. Filler circulation loop; 214. Drainage tank; 215. Baffle.

[0019] It should be noted that these attached drawings and text descriptions are not intended to limit the scope of the concept of the present invention in any way, but to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed description of specific embodiments

[0020] The present invention will now be further described in detail with reference to the attached drawings.

[0021] Please refer to Figure 1-2 As shown, in this embodiment, a moving bed biofilm reactor is provided, including an anaerobic tank 22, an anoxic tank 23, an aerobic tank 24, a drainage tank 214, and a curved filler 1 that moves in the anoxic tank 23 and the aerobic tank 24. A water inlet 21 is provided on the first side at the upper end of the anaerobic tank 22, and a communication port A communicating with the anoxic tank 23 is provided on the second side. Among them, sewage flows into the anaerobic tank 22 through the water inlet 21, and the sewage flowing into the anaerobic tank 22 flows into the anoxic tank 23 through the communication port A; A communication port B is provided on the side of the bottom of the anoxic tank 23 away from the anaerobic tank 22, and the anoxic tank 23 and the aerobic tank 24 are communicated through the communication port B; A vortex plate separation layer 210 for extending the hydraulic retention time of the curved filler 1 is provided above the aerobic tank 24. The upper part of the vortex plate separation layer 210 is communicated with a filler circulation loop 213. The filler circulation loop 213 is communicated with the anoxic tank 23, and a circulation pump 211 is provided in the filler circulation loop 213 to form a reflux of the curved filler 1 with the anoxic tank 23; In the present invention, the vortex plate separation layer 210 above the aerobic tank 24 can extend the hydraulic retention time of the filler, promote the growth of aerobic microorganisms and the progress of nitrification reaction, thereby improving the removal effect of organic matter and nitrogen pollutants in sewage. In addition, the design of the filler circulation loop 213 realizes the dynamic circulation of the curved filler 1 between the anoxic tank 23 and the aerobic tank 24 through the circulation pump 211, increases the utilization rate of the filler, enables its rate to be significantly improved, and at the same time reduces the problem of biofilm aging caused by the long-term retention of the filler in a single area.

[0022] A drain outlet is provided on one side of the bottom of the aerobic tank 24 away from the anoxic tank 23. The aerobic tank 24 is communicated with the drainage tank 214 through the drain outlet. A switchable screen 212 is arranged in the drain outlet to control the discharge of the treated sewage and filter the curved surface filler 1. An outlet 25 for discharging the treated sewage is opened on one side of the drainage tank 214 away from the aerobic tank 24.

[0023] It should be noted that the design of the multi-stage reaction tank realizes the efficient division of labor for anaerobic, anoxic and aerobic treatment, and is suitable for the synchronous treatment of organic pollutant removal, denitrification and phosphorus removal.

[0024] When in use, sewage flows into the anaerobic tank 22 through the water inlet 21, and then enters the anoxic tank 23 through the upper circulation port A. The aeration pump in the anoxic tank 23 will give the first wave of impact to the curved surface filler 1, and then flows into the aerobic zone through the bottom circulation port B and receives the second wave of impact from the aerobic aeration pump A 28. Then it is lifted by the aerobic aeration pump B 29 into the vortex plate separation layer 210. And due to the vortex generated by the structure of the separation layer, the curved surface filler 1 has a longer hydraulic retention time in it. This characteristic is beneficial to more sufficient water treatment, and at the same time provides some scenarios and time for supplementing special functional bacteria obtained from the sewage for the complex structure of this kind of curved surface filler 1. Then the curved surface filler 1 flows back to the anoxic tank 23 through the circulation pump 211. The switchable screen 212 can control the outflow of the treated sewage. These structures realize the reuse of the curved surface filler 1 and the separation of the treated water.

[0025] In this embodiment, an anoxic aeration pump 26 and an anaerobic aeration pump 27 are respectively arranged at the bottoms of the anaerobic tank 22 and the anoxic tank 23. The bottom of the aerobic tank 24 is successively provided with an aerobic aeration pump A 28 and an aerobic aeration pump B 29 from left to right. Among them, the aeration direction of the aerobic aeration pump B 29 is directly below the inlet of the vortex plate separation layer 210, and the anaerobic aeration pump 27 is located below the filler circulation loop 213.

[0026] In this embodiment, the vortex plate separation layer 210 is located at the upper half of the aerobic tank 24.

[0027] In this embodiment, the vortex plate separation layer 210 is composed of a number of vortex plates arranged from top to bottom. Among them, the gap between every two adjacent vortex plates is 2 to 4 times the diameter of the curved surface filler 1. The number of layers of the vortex plates is determined according to the device height and the plate gap.

[0028] In this embodiment, the switchable screen 212 is composed of a screen and a baffle 215, wherein the baffle 215 is rotatably connected to one side of the screen, and the baffle 215 is located in the drainage pool 214 after rotation. Specifically, the baffle 215 can be rotated by a waterproof motor. The length-to-depth ratio of a single reactor in the moving bed biofilm reactor is 0.4-0.6, and the length is not more than 3m.

[0029] Working principle: When in use, the water inlet 21 guides the first wave of sewage into the anaerobic tank 22. The anaerobic tank 22 can withstand the first wave of impact brought by high-concentration sewage, and then enters the anoxic tank 23 through the upper flow port A. The anoxic tank 23 contains biofilm curved surface filler 1, and the filling ratio is >40%. The biofilm curved surface filler 1 has functional bacterial biofilm, which will pre-treat the sewage and complete the denitrification work. The aeration pump can ensure the continuous movement of the biofilm curved surface filler 1 to enhance its removal effect by driving the water flow. Then the biofilm curved surface filler 1 and the sewage flow into the aerobic zone through the bottom flow port B. With the assistance of the aerobic aeration pump A28, the biofilm curved surface filler 1 begins to nitrify the sewage. Then the biofilm curved surface filler 1 is lifted by the aerobic aeration pump B29 into the vortex plate separation layer 210. Due to the vortex generated by the structure of the separation layer, the curved surface filler 1 has a longer hydraulic retention time in it. This feature is conducive to more complete water treatment, and provides some scenes and time for the complex structure of the curved surface filler 1 to be supplemented with special functional bacteria obtained from sewage. Then the curved surface filler 1 is returned to the anoxic tank 23 through the circulation pump 211. The switchable screen 212 is closed in the initial state. After the sewage water level can stably support the circulation of the aerobic tank 24 and the anoxic tank 23 and the sewage treatment effect is stable, the screen switch is turned on to allow the treated sewage to flow out from the outlet 25. The aerobic aeration pump B29, the vortex plate separation layer 210, the circulation pump 211 and the switchable screen 212 realize the reuse of the curved surface filler 1 and the separation of the treated water.

[0030] A method for preparing a curved surface filler comprises the following steps: Substitute the minimal surface formula into Mathematica software to obtain its 3D modeling model; Commercial photosensitive resin and porogen polyethylene glycol were mixed in a predetermined ratio and stirred evenly as raw materials for 3D printing. It should be noted that the mixing process was carried out at room temperature of 15-30°C in the dark, with a stirring rate of 100-500 rpm and a stirring time of 0.5-12 hours. After mixing, the mixture was placed in a light-proof container and stored at 4°C for a long time.

[0031] Input the 3D modeling file designed with the above configuration into the slicing software of the 3D printer for slicing. Subsequently, import the sliced file into the 3D printer, inject the photosensitive resin mixture into the printing tank, and start the 3D printer to print the configuration. After printing is completed, wash the printed surface filler 1 with a solvent multiple times to remove surface residues. Subsequently, place the surface filler 1 in an ultraviolet curing device for secondary curing, thereby completing the preparation of the surface filler 1. In the present invention, the three-dimensional surface design of the surface filler 1 has a complex topological structure, and the minimal surface provides a higher specific surface area, capable of accommodating more microbial attachment and growth. This design significantly improves the biofilm carrying capacity of the filler, thereby enhancing the sewage treatment efficiency. In addition, its smooth and continuous surface and porous structure can effectively reduce the fluid resistance, enabling the filler to have better flow performance in the sewage treatment device. The hole design on the surface allows water flow to pass through and form vortices, prolonging the water residence time, increasing the contact opportunity between water and microorganisms, and improving the pollutant degradation efficiency.

[0032] In this embodiment, the polyethylene glycol is one of low-polymerization PEG-200, PEG-400 and high-polymerization PEG-2000, PEG-4000.

[0033] In this embodiment, the raw materials for 3D printing photo-curing, the commercial photosensitive resin and the pore-forming agent polyethylene glycol, are mixed in a ratio of 6-9:4-1.

[0034] In this embodiment, when substituting into the Mathematica software to obtain the implicit function expression of the surface structure of its 3D modeling model: Sin[x]Cos[y]+Sin[y]Cos[z]+Sin[z]Cos[x]=C, {x, -r, r}, {y, -r, r}, {z, -r, r}, where x, y, and z are the three coordinates of the coordinate system, r is the radius, and C is the threshold; by adjusting the size of r to achieve the pore size and density of the surface filler 1, and by adjusting C to control the wall thickness of the seasoning.

[0035] In this embodiment, the 3D printing parameters are set as follows: layer thickness 0.05-0.1 mm, exposure time 2-5 s, bottom exposure time 30-60 s, and bottom number of layers 3-8 layers.

[0036] Example 1: This example provides a method for constructing a model of a filler. First, the formula Sin[x]Cos[y]+Sin[y]Cos[z]+Sin[z]Cos[x]=C, {x, -r,r}, {y, -r, r}, {z, -r, r} is constructed in the software Wolfram Mathematica 13.3; the parameters are selected as: r = 4pi, C ≤ 0.1norm; norm = normal2; normal = Grad[C, (x, y, z)]. Subsequently, the generated 3D model is calculated, the STL file is exported, the STL file is imported into the graphics slicing software adapted to the 3D printer, the diameter of the filler is set to 10 mm, and then the sliced file is exported and imported into the 3D printer for use.

[0037] The photocurable resin is richopto 306 type LCD water-washable photosensitive resin, and the polyethylene glycol is low-polymerization PEG-200. The photocurable resin and polyethylene glycol are mixed in a ratio of 7:3, and stirred in the dark at room temperature of 25°C, with a stirring rate of 300 rpm and a stirring time of 12 h. After mixing, it is placed in a light-shielded container and stored long-term at 4°C. The 3D printing parameters are set as follows: layer thickness 0.05 mm, exposure time 3.5 s, bottom exposure time 40 s, and bottom number of layers 7 layers.

[0038] The present invention is not limited to the above embodiments. Anyone should know that structural changes made under the inspiration of the present invention, as long as they have the same or similar technical solutions as the present invention, fall within the protection scope of the present invention. The technologies, shapes, and structures not described in detail in the present invention are all well-known technologies.

Claims

1. A moving bed biofilm reactor device, characterized in that It includes an anaerobic tank (22), an anoxic tank (23), an aerobic tank (24), a drainage tank (214), and a curved surface filler (1) that moves in the anoxic tank (23) and the aerobic tank (24). An inlet (21) is provided on the first side at the upper end of the anaerobic tank (22), and a communication port A for communicating with the anoxic tank (23) is provided on the second side. A communication port B is provided on the side of the bottom of the anoxic tank (23) away from the anaerobic tank (22). The anoxic tank (23) and the aerobic tank (24) are communicated through the communication port B. Above the aerobic tank (24), there is a vortex plate separation layer (210) for extending the hydraulic retention time of the curved surface filler (1). Above the vortex plate separation layer (210), there is a filler circulation loop (213) connected. The filler circulation loop (213) is connected to the anoxic tank (23), and a circulation pump (211) is provided in the filler circulation loop (213) to form a reflux of the curved surface filler (1) with the anoxic tank (23). A drain port is provided on the side of the bottom of the aerobic tank (24) away from the anoxic tank (23). The aerobic tank (24) is communicated with the drainage tank (214) through the drain port. A switchable screen (212) is provided in the drain port to control the discharge of the treated sewage and filter the curved surface filler (1). An outlet (25) for discharging the treated sewage is provided on the side of the drainage tank (214) away from the aerobic tank (24).

2. The moving bed biofilm reactor device according to claim 1, characterized in that, An anoxic aeration pump (26) and an anaerobic aeration pump (27) are respectively provided at the bottoms of the anaerobic tank (22) and the anoxic tank (23). At the bottom of the aerobic tank (24), an aerobic aeration pump A (28) and an aerobic aeration pump B (29) are arranged in sequence from left to right. Among them, the aeration direction of the aerobic aeration pump B (29) is directly below the inlet of the vortex plate separation layer (210), and the anaerobic aeration pump (27) is located below the filler circulation loop (213).

3. The moving bed biofilm reactor device according to claim 1, characterized in that, The vortex plate separation layer (210) is located at the upper 1 / 2 of the aerobic tank (24). The vortex plate separation layer (210) is composed of several vortex plates arranged from top to bottom. Among them, the gap between every two adjacent vortex plates is 2 to 4 times the diameter of the curved surface filler (1).

4. A moving bed biofilm reactor device according to claim 1, characterized in that, The switchable screen (212) is composed of a screen and a baffle (215). Among them, the baffle (215) is rotatably connected to one side of the screen, and the baffle (215) is located in the drainage tank (214) after rotation.

5. A preparation method of a curved surface filler, characterized in that, The curved surface filler (1) is applicable to the moving bed biofilm reaction device described in claim 1, serves as a carrier for microbial attachment, and optimizes the hydraulic characteristics of sewage treatment. The preparation method includes the following steps: Substitute the minimal surface formula into the Mathematica software to obtain its 3D modeling model; Mix commercial photosensitive resin and the pore-forming agent polyethylene glycol in a predetermined ratio and stir evenly as the raw material for 3D printing; Input the 3D modeling file designed above into the slicing software of the 3D printer for slicing processing, then import the sliced file into the 3D printer, inject the photosensitive resin mixture into the printing tank, and start the 3D printer to print the configuration; After printing is completed, the printed curved surface filler (1) is washed multiple times with a solvent to remove surface residues, and then the curved surface filler (1) is placed in an ultraviolet curing device for secondary curing, thus completing the preparation of the curved surface filler (1).

6. The preparation method of a curved surface filler according to claim 5, characterized in that, The polyethylene glycol is one of low-polymerization PEG-200, PEG-400 and high-polymerization PEG-2000, PEG-4000, and the photocurable resin is richopto 306 type LCD water-washable photosensitive resin.

7. The preparation method of the curved surface filler according to claim 5, characterized in that, The raw materials for 3D printing photocuring, the commercial photosensitive resin and the pore-forming agent polyethylene glycol, are mixed in a ratio of 6 - 9:4 - 1.

8. The preparation method of the curved surface filler according to claim 5, characterized in that, Substituting into the Mathematica software to obtain the implicit function expression of the curved surface structure in its 3D modeling model as: Sin[x]Cos[y]+Sin[y]Cos[z]+Sin[z]Cos[x]=C, {x, -r, r}, {y, -r, r}, {z, -r, r}, where x, y, and z are the three coordinates of the coordinate system, r is the radius, and C is the threshold; the pore size and density of the curved surface filler (1) are achieved by adjusting the size of r, and the wall thickness of the filler is controlled by adjusting C.

9. The preparation method of the curved surface filler according to claim 8, characterized in that, The 3D printing parameters are set as follows: layer thickness 0.05 - 0.1 mm, exposure time 2 - 5 s, bottom exposure time 30 - 60 s, and bottom number of layers 3 - 8 layers.

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