A moving bed biofilm reactor and a method for manufacturing a curved filler

Abstract

The application discloses a kind of mobile bed biological membrane reaction device and the preparation method of curved filler, the present application is based on triple minimum surface biomimetic structure to the optimization design of existing filler structure, utilize 3D printing technology to make out microporous minimum surface filler, significantly increase the biological membrane attachment amount of unit area, its structural complexity can make biological membrane be free from fluid shear force influence, and due to the flow state of each surface is different, this can stimulate unique heterogenous biological membrane development;At the same time, the present application is optimized and designed to MBBR structure, improve the space utilization efficiency of equipment, separate layer is designed in aerobic zone, so that the region produces vortex, increase the hydraulic retention time of filler, by which realize filler biological membrane replenishment and efficient sewage treatment.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment, specifically relating to a moving bed biofilm reactor and a method for preparing curved packing material. Background Technology

[0002] Moving bed biofilm reactors (MBBRs) are an innovative wastewater treatment technology that cleverly combines the advantages of activated sludge processes (suspended microorganisms) and biofilm processes (attached microorganisms). Originating in the mid-1980s, this technology centers on using lightweight packing material (with a density similar to water, allowing it to suspend in aeration tank) as a substrate for microbial attachment. Through aeration, the packing material remains in a flowing state, thoroughly mixing with the wastewater, enabling microorganisms to grow in a three-phase environment (gas, liquid, and solid). In this environment, anaerobic or facultative anaerobic bacteria proliferate extensively inside the packing material, while aerobic bacteria dominate the exterior. Each packing particle acts as a miniature bioreactor, allowing nitrification and denitrification processes to occur simultaneously.

[0003] In existing moving bed biofilm reactor (MBBR) technologies, the packing material structure typically employs simple geometric shapes, such as hollow spheres or ring structures. While these provide some space for microbial attachment, their insufficient specific surface area results in a limited amount of biofilm attached per unit volume, making it difficult to meet the demands of high-load wastewater treatment. Furthermore, traditional packing materials are susceptible to damage from fluid shear forces under high flow velocities, leading to biofilm detachment and poor stability, making long-term operation unsustainable. Simultaneously, existing MBBR devices exhibit short hydraulic retention times in the aerobic zone and uneven flow distribution, resulting in low packing material utilization and inefficient biofilm replenishment, further reducing wastewater treatment effectiveness.

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

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a moving bed biofilm reactor and a method for preparing curved packing material, thereby solving the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows: A moving bed biofilm reactor includes: an anaerobic tank, an anoxic tank, an aerobic tank, a drainage tank, and curved packing material moving in the anoxic tank and the aerobic tank. The first side of the upper end of the anaerobic tank is provided with an inlet, and the second side is provided with a flow port A that communicates with the anoxic tank. A flow port B is provided at the bottom of the anoxic tank on the side away from the anaerobic tank, and the anoxic tank and the aerobic tank are connected through the flow port B. A vortex plate separation layer is provided above the aerobic tank to extend the hydraulic residence time of the curved packing. A packing circulation loop is connected above the vortex plate separation layer, and the packing circulation loop is connected to the anoxic tank. A circulation pump is provided in the packing circulation loop to form a return flow of the curved packing with the anoxic tank. A drain outlet is provided on the side of the bottom of the aerobic tank away from the anoxic tank. The aerobic tank is connected to the drainage tank through the drain outlet. An openable screen is installed in the drain outlet to control the discharge of treated wastewater and to filter the curved packing. An outlet for discharging treated wastewater is opened on the side of the drainage tank away from the aerobic tank.

[0007] Optionally, the bottom of the anaerobic tank and the anoxic tank are respectively equipped with an anoxic aeration pump and an anaerobic aeration pump. The bottom of the aerobic tank is equipped with an aerobic aeration pump A and an aerobic aeration pump B from left to right. 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 upper half of the aerobic tank. The vortex plate separation layer is composed of several vortex plates arranged from top to bottom, wherein the gap between every two adjacent vortex plates is 2 to 4 times the diameter of the curved packing.

[0009] Optionally, the switchable screen consists of a screen and a baffle, wherein the baffle is rotatably connected to one side of the screen and is positioned inside the drainage tank after rotation. Specifically, the baffle can be rotated by a waterproof motor.

[0010] A method for preparing a curved packing material, the curved packing material being suitable for the aforementioned moving bed biofilm reactor, serving as a carrier for microbial attachment and optimizing the hydraulic characteristics of wastewater treatment, the preparation method comprising the following steps: Substituting the formula for the minimum surface into Mathematica software, we obtain its 3D modeling model. Commercial photosensitive resin and porogen polyethylene glycol are mixed in a predetermined ratio and stirred evenly to serve as raw materials for 3D printing. The 3D modeling file of the above configuration design is input into the slicing software of the 3D printer for slicing. Then the sliced ​​file is imported into the 3D printer, the photosensitive resin mixture is injected into the printing tank, and the 3D printer is started to print the configuration. After printing, the printed curved filler is cleaned multiple times with solvent to remove surface residues. Then, the curved filler is placed in a UV curing device for secondary curing, thus completing the preparation of the curved filler.

[0011] Optionally, the polyethylene glycol is divided into one of the following: low-polymer PEG-200, PEG-400, and high-polymer PEG-2000, PEG-4000. The photocurable resin is Richopto 306 LCD water-washable photosensitive resin.

[0012] Optionally, the raw materials for 3D printing photocuring are commercial photosensitive resin and porogen polyethylene glycol 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, it is: 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 surface filler are realized by adjusting the value of r, and the wall thickness of the filler is controlled by adjusting C.

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

[0015] By 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 of the following advantages at the same time: This invention optimizes existing packing structures based on a triple minimal curved surface biomimetic design, utilizing 3D printing technology to fabricate microporous minimal curved surface packing, significantly increasing the biofilm attachment per unit area. Its structural complexity protects the biofilm from fluid shear forces, and the different flow patterns on each surface stimulate the development of unique heterogeneous biofilms. Simultaneously, this invention optimizes the MBBR structure, improving the space utilization efficiency of the equipment. A separation layer is designed in the aerobic zone, generating eddies and increasing the hydraulic retention time of the packing, thereby achieving biofilm replenishment and efficient wastewater treatment. The MBBR device using minimal curved surface packing proposed in this invention not only increases biofilm loading and distribution but also saves equipment floor space, achieving more effective wastewater treatment.

[0016] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0017] The accompanying drawings described below are merely some embodiments. Those skilled in the art can obtain other drawings based on these drawings without any creative effort. In the drawings: Figure 1 This is a schematic diagram of the packing material in this invention; Figure 2 This is a side view of the moving bed biofilm reactor in this invention.

[0018] In the attached diagram, the components represented by each number are as follows: 1. Packing material; 21. Inlet; 22. Anaerobic tank; 23. Anoxic tank; 24. Aerobic tank; 25. 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. Packing material circulation loop; 214. Drainage tank; 215. Baffle.

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

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

[0021] Please see Figure 1-2 As shown, this embodiment provides a moving bed biofilm reactor, including an anaerobic tank 22, an anoxic tank 23, an aerobic tank 24, a drainage tank 214, and curved packing material 1 that moves in the anoxic tank 23 and the aerobic tank 24. The first side of the upper end of the anaerobic tank 22 is provided with an inlet 21, and the second side is provided with a flow port A that communicates with the anoxic tank 23. Sewage flows into the anaerobic tank 22 through the inlet 21, and the sewage flowing into the anaerobic tank 22 flows into the anoxic tank 23 through the sewage flow port A. A flow 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 connected through the flow port B. Above the aerobic tank 24, a vortex plate separation layer 210 is provided to extend the hydraulic retention time of the curved packing material 1. Above the vortex plate separation layer 210, a packing material circulation loop 213 is connected, which is connected to the anoxic tank 23. A circulation pump 211 is installed in the packing material circulation loop 213 to form a reflux of the curved packing material 1 with the anoxic tank 23. In this invention, the vortex plate separation layer 210 above the aerobic tank 24 can extend the hydraulic retention time of the packing material, promote the growth of aerobic microorganisms and the nitrification reaction, thereby improving the removal efficiency of organic matter and nitrogen pollutants in wastewater. Furthermore, the design of the packing material circulation loop 213, through the circulation pump 211, enables dynamic circulation of the curved packing material 1 between the anoxic tank 23 and the aerobic tank 24, increasing the utilization rate of the packing material and significantly improving its efficiency, while reducing the biofilm aging problem caused by the packing material remaining in a single area for a long time.

[0022] A drain outlet is provided on the side of the bottom of the aerobic tank 24 away from the anoxic tank 23. The aerobic tank 24 is connected to the drainage tank 214 through the drain outlet. A switchable screen 212 is provided in the drain outlet to control the discharge of treated wastewater and to filter the curved packing 1. An outlet 25 for discharging treated wastewater is provided on the 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 achieves efficient division of labor for anaerobic, anoxic and aerobic treatment, and is suitable for the simultaneous treatment of organic pollutant removal, denitrification and phosphorus removal.

[0024] During use, wastewater flows into the anaerobic tank 22 through inlet 21, and then into the anoxic tank 23 through the upper flow port A. The aeration pump in the anoxic tank 23 provides the first wave of impact to the curved packing material 1. It then flows into the aerobic zone through the bottom flow port B and receives the second wave of impact from the aerobic aeration pump A28. Subsequently, it is lifted into the vortex plate separation layer 210 by the aerobic aeration pump B29. Due to the vortex generated by the structure of the separation layer, the curved packing material 1 has a longer hydraulic retention time. This characteristic facilitates more thorough water treatment and provides the complex structure of the curved packing material 1 with a suitable environment and time for the replenishment of specialized functional bacteria obtained from the wastewater. The curved packing material 1 is then returned to the anoxic tank 23 via the circulation pump 211. The switchable screen 212 controls the outflow of treated wastewater. These structures enable the reuse of the curved packing material 1 and the separation of treated water.

[0025] In this embodiment, the bottom of the anaerobic tank 22 and the anoxic tank 23 are respectively equipped with anoxic aeration pump 26 and anaerobic aeration pump 27. The bottom of the aerobic tank 24 is equipped with aerobic aeration pump A28 and aerobic aeration pump B29 from left to right. The aeration direction of aerobic aeration pump B29 is directly below the inlet of the vortex plate separation layer 210, and anaerobic aeration pump 27 is located below the packing 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 several vortex plates arranged from top to bottom, wherein the gap between any two adjacent vortex plates is 2 to 4 times the diameter of the curved filler 1. The number of vortex plate layers 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. The baffle 215 is rotatably connected to one side of the screen and, after rotation, is located within the drainage tank 214. 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 no more than 3m.

[0029] Working principle: During operation, inlet 21 guides the first wave of wastewater into anaerobic tank 22, which can withstand the initial impact of high-concentration wastewater. The wastewater then flows into anoxic tank 23 through upper outlet A. Anoxic tank 23 contains biofilm curved packing material 1 with a filling ratio >40%. Biofilm curved packing material 1 facilitates bacterial attachment, pre-treating the wastewater and completing denitrification. The aeration pump drives the water flow, ensuring continuous movement of the biofilm curved packing material 1 and enhancing its removal efficiency. Subsequently, the biofilm curved packing 1 and wastewater flow into the aerobic zone through the bottom flow port B. With the assistance of the aerobic aeration pump A28, the biofilm curved packing 1 begins nitrification of the wastewater. Then, the biofilm curved packing 1 is lifted into the vortex plate separation layer 210 by the aerobic aeration pump B29. Due to the vortex generated by the structure of the separation layer, the curved packing 1 has a longer hydraulic retention time within it. This characteristic facilitates more thorough water treatment and provides the complex structure of the curved packing 1 with a suitable environment and time for the replenishment of specialized functional bacteria obtained from the wastewater. The curved packing 1 is then returned to the anoxic tank 23 via the circulation pump 211. The switchable screen 212 is initially closed. Once the wastewater level can stably support the circulation between the aerobic tank 24 and the anoxic tank 23, and the wastewater treatment effect has stabilized, the screen switch is opened, allowing the treated wastewater 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 enable the reuse of the curved packing 1 and the separation of treated water.

[0030] A method for preparing a curved surface filler includes the following steps: Substituting the formula for the minimum surface into Mathematica software, we obtain its 3D modeling model. Commercial photosensitive resin and porogen polyethylene glycol were mixed in a predetermined ratio and stirred until homogeneous, serving as the raw material for 3D printing. It should be noted that the mixing process was carried out at room temperature (15-30℃) in the dark, at a stirring speed of 100-500 rpm, for a stirring time of 0.5-12 hours. After mixing, the mixture was placed in a light-proof container and stored at 4℃ for long-term storage.

[0031] The 3D modeling file of the above configuration design is input into the slicing software of the 3D printer for slicing. Then the sliced ​​file is imported into the 3D printer, the photosensitive resin mixture is injected into the printing tank, and the 3D printer is started to print the configuration. After printing, the printed curved filler 1 is repeatedly cleaned with solvent to remove surface residues. Then, the curved filler 1 is placed in a UV curing device for secondary curing, thus completing the preparation of the curved filler 1. The three-dimensional curved surface design of the curved filler 1 in this invention has a complex topological structure. The minimal curved surface provides a higher specific surface area, enabling it to accommodate more microbial attachment and growth. This design significantly improves the biofilm carrying capacity of the filler, thereby enhancing wastewater treatment efficiency. Furthermore, its smooth and continuous curved surface and porous structure effectively reduce fluid resistance, giving the filler better flow performance in wastewater treatment devices. The perforated design on the curved surface allows water to flow through and form eddies, extending the water residence time, increasing the contact opportunities between water and microorganisms, and improving pollutant degradation efficiency.

[0032] In this embodiment, polyethylene glycol is divided into 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 photocuring, commercial photosensitive resin and porogen polyethylene glycol, are mixed in a ratio of 6~9:4~1.

[0034] In this embodiment, when the implicit function expression of the surface structure is obtained by substituting it into Mathematica software, it is: 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 surface filler 1 are realized by adjusting the value of r, and the wall thickness of the filling material is controlled by adjusting C.

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

[0036] Example 1: This example provides a method for constructing a filler model. First, in the software WolframMathematica 13.3, 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; the parameters are selected as follows: r=4pi, C≤0.1norm; norm=normal2; normal=Grad [C, (x, y, z)]. Then, the generated 3D model is calculated, and an STL file is exported. The STL file is imported into the graphics slicing software adapted for the 3D printer. The diameter of the filler is set to 10 mm. The sliced ​​file is then exported and imported into the 3D printer for use.

[0037] The photocurable resin was Richopto 306 LCD water-washable photosensitive resin, and the polyethylene glycol was low-polymerization PEG-200. The photocurable resin and polyethylene glycol were mixed in a 7:3 ratio and stirred in the dark at 25°C for 12 hours. After mixing, the mixture was placed in a light-proof container and stored at 4°C for an extended period. The 33D printing parameters were set as follows: layer thickness 0.05 mm, exposure time 3.5 s, bottom exposure time 40 s, and 7 bottom layers.

[0038] This invention is not limited to the embodiments described above. Anyone should understand that structural changes made under the guidance of this invention, and any technical solutions that are the same as or similar to this invention, fall within the protection scope of this invention. Technical aspects, shapes, and structures not described in detail in this invention are all publicly known technologies.

Claims

1. A moving bed biofilm reactor, characterized in that, It includes an anaerobic tank (22), an anoxic tank (23), an aerobic tank (24), a drainage tank (214), and curved packing material (1) moving in the anoxic tank (23) and the aerobic tank (24). The curved packing material (1) is a microporous curved packing material made using 3D printing technology. The first side of the upper end of the anaerobic tank (22) is provided with an inlet (21), and the second side is provided with a flow port A that connects with the anoxic tank (23). A flow 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 connected through the flow port B; a vortex plate separation layer (210) is provided above the aerobic tank (24) to extend the hydraulic residence time of the curved packing (1), and a packing circulation loop (213) is connected above the vortex plate separation layer (210), and the packing circulation loop (213) is connected to the anoxic tank (23), and a circulation pump (211) is provided in the packing circulation loop (213) to form a return flow of the curved packing (1) with the anoxic tank (23); The aerobic tank (24) has a drain outlet on the side away from the anoxic tank (23) at the bottom. The aerobic tank (24) is connected to the drainage tank (214) through the drain outlet. The drain outlet is equipped with a switchable screen (212) to control the discharge of treated wastewater and filter the curved packing material (1). The drainage tank (214) has an outlet (25) on the side away from the aerobic tank (24) for discharging treated wastewater. The bottom of the anaerobic tank (22) and the anoxic tank (23) are respectively equipped with anoxic aeration pump (26) and anaerobic aeration pump (27). The bottom of the aerobic tank (24) is equipped with aerobic aeration pump A (28) and aerobic aeration pump B (29) from left to right. The aeration direction of aerobic aeration pump B (29) is directly below the inlet of the vortex plate separation layer (210), and anaerobic aeration pump (27) is located below the packing circulation loop (213). The vortex plate separation layer (210) is located 1 / 2 above the aerobic tank (24). The vortex plate separation layer (210) is composed of several vortex plates arranged from top to bottom. The gap between each two adjacent vortex plates is 2 to 4 times the diameter of the curved packing (1). 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 is located in the drainage pool (214) after the baffle (215) is rotated.

2. The moving bed biofilm reactor according to claim 1, characterized in that, A method for preparing curved surface fillers, the method comprising the following steps: Substituting the formula for the minimum surface into Mathematica software, we obtain its 3D modeling model. Commercial photosensitive resin and porogen polyethylene glycol are mixed in a predetermined ratio and stirred evenly to serve as raw materials for 3D printing. The 3D modeling file of the above configuration design is input into the slicing software of the 3D printer for slicing. Then the sliced ​​file is imported into the 3D printer, the photosensitive resin mixture is injected into the printing tank, and the 3D printer is started to print the configuration. The 3D printing parameters are set as follows: layer thickness 0.05~0.1mm, exposure time 2~5s, bottom exposure time 30~60s, and bottom layer number 3~8. After printing, the printed curved filler (1) is cleaned multiple times with solvent to remove surface residues. Then, the curved filler (1) is placed in a UV curing device for secondary curing, thus completing the preparation of the curved filler (1).

3. The moving bed biofilm reactor according to claim 2, characterized in that, Polyethylene glycol is classified into one of the following: low-polymerization PEG-200, PEG-400, and high-polymerization PEG-2000, PEG-4000. The photocurable resin is Richopto 306 LCD water-washable photosensitive resin.

4. The moving bed biofilm reactor according to claim 3, characterized in that, The raw materials for 3D printing photopolymerization are commercial photosensitive resin and porogen polyethylene glycol mixed in a ratio of 6~9:4~1.

5. A moving bed biofilm reactor according to claim 4, characterized in that, When the implicit function expression of the surface structure is obtained by substituting it into the Mathematica software, it is: 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 surface filler (1) are realized by adjusting the size of r, and the wall thickness of the filler is controlled by adjusting C.

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