Preparation method of multi-scale gridding metazoan carrier for sludge reduction
By constructing a stable food chain using a multi-scale gridded metazoan carrier, the problems of high sludge production and high treatment costs in sludge treatment were solved, achieving efficient sludge reduction and improved wastewater treatment efficiency.
Patent Information
- Application Number
- CN202610447949.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-07
- Publication Date
- 2026-05-19
AI Technical Summary
Existing sludge treatment technologies suffer from problems such as high sludge production, high treatment costs, and significant environmental risks. The lack of suitable carriers makes it impossible to effectively construct a stable food chain, resulting in low sludge reduction efficiency.
The design incorporates a multi-scale gridded metazoan carrier, providing suitable activity space for metazoans and protozoa through hierarchical grids, constructing a stable food chain, and employing biomimetic topology and biofilm covering treatment. By optimizing pore structure and material selection, the design achieves efficient sludge reduction.
It significantly improves sludge reduction efficiency, increases SS and VSS digestion rates by 10% to 15%, reduces treatment costs, is environmentally friendly and easy to scale up, and is in line with the concept of sustainable development.
Smart Images
Figure CN122059595A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of bioimmobilization technology and relates to a method for preparing a multi-scale gridded post-biota carrier for sludge reduction. Background Technology
[0002] In existing biological wastewater treatment processes, the large-scale generation of sludge has become a major challenge in solid waste treatment and disposal. With the acceleration of urbanization and the continuous expansion of industrial development, wastewater discharge is constantly increasing, leading to a rapid growth in sludge production. This sludge is rich in organic matter, heavy metals, and other harmful substances. If it is not effectively treated, it will not only cause secondary pollution to the environment but also pose a threat to human health and ecological security.
[0003] Currently, the main methods for treating and disposing of sludge include landfill, incineration, and composting. However, these methods all have certain limitations. Landfilling requires a large amount of land resources, and the process may generate leachate and odors, posing potential environmental risks. Incineration, while reducing the volume of sludge, produces harmful gases and ash, and its treatment costs are relatively high. Composting requires low levels of heavy metals and other harmful substances in the sludge, limiting its applicability. Therefore, finding a more efficient and environmentally friendly method for treating and disposing of sludge is particularly urgent.
[0004] Among common technologies for sludge reduction, dewatering, pyrolysis, microbial treatment, and vitrification each have their advantages, but also present numerous challenges. For example, while dewatering can reduce sludge volume, the dewatered sludge still requires further processing; pyrolysis can simultaneously reduce sludge volume and organic matter content, but its equipment investment and operating costs are high; microbial treatment is environmentally friendly, but its processing cycle is long and it has certain requirements regarding the composition and properties of the sludge; vitrification can stabilize organic matter, but the process requires high temperature and pressure conditions, resulting in significant energy consumption. Against this backdrop, attempts to reduce sludge volume using food chain technology have gradually gained attention. This technology constructs a stable ecological chain, utilizing the interactions between different organisms to achieve effective degradation of organic matter in sludge and reduce sludge volume. However, to achieve this technology, a suitable carrier is crucial for sludge reduction food chain technology; its structural design directly affects metazoan colonization, microbial interactions, and pollutant degradation efficiency. While the porous ceramic carrier in patent CN113698278A boasts high mechanical strength, its uneven pore size distribution results in a metazoan colonization rate of less than 30%. The high-efficiency biological carrier mentioned in patent CN217868558U, although achieving over 80% sludge reduction, lacks optimized pore size gradients, only enriching basic bacterial flocs and failing to form multi-level food chains. Even patent CN108660475A, which attempts to enhance mass transfer through carrier modification, still fails to address the compatibility issue between pore structure and biological community, unable to meet the requirements of optimal 300μm pore size and multi-level distribution. Currently, there is no suitable carrier on the market that can meet this requirement.
[0005] This invention aims to solve the solid waste problem in sludge treatment and disposal by constructing a multi-scale gridded metazoan carrier, achieving efficient sludge reduction. This carrier not only effectively restricts the activity range of metazoans, improving their utilization efficiency in wastewater treatment, but also promotes the degradation of organic matter and sludge reduction by constructing a stable food chain. The successful application of this technology will provide new ideas and methods for technological advancement in the field of wastewater treatment, and is of great significance for promoting the development of the environmental protection industry. Summary of the Invention
[0006] This invention is made in view of the above-mentioned problems existing in the prior art. The purpose of this invention is to provide a multi-scale gridded metazoan carrier for sludge reduction, so as to achieve the goal of efficient sludge reduction.
[0007] The novelty of this invention lies in its multi-scale gridded structural design and the synergistic optimization of process and function. Addressing the pain point of the lack of suitable carriers for food chain sludge reduction technologies, a hierarchical grid design is employed to provide adsorption and anti-pollution activity spaces for metazoans, protozoa, and microorganisms. This design overcomes the limitations of traditional single-structure carriers, precisely matching different biological niches, constructing a stable food chain, significantly improving sludge reduction efficiency, increasing SS and VSS dissipation rates by 10%–15%, and offering a simple, highly adaptable process that is easily scalable.
[0008] The technical solution of this invention: A method for preparing a multi-scale gridded metazoan carrier for sludge reduction, comprising the following steps: Step 1: Select the materials for making the carrier according to the application requirements; For large-scale grids, materials that are corrosion-resistant, wear-resistant, and have a certain strength and toughness are selected, such as carbon fiber, nylon mesh, and glass wool. For small-scale meshes, materials with good biocompatibility are selected, such as extruded micron-sized fiber bundles or micro / nano-sized glass fibers. Step 2: Design a multi-scale grid structure based on the expected sludge treatment volume and the activity habits of metazoans; Metazoans have an activity space of 80-100 mesh, while protozoa have an activity space of 200-800 mesh. The above principles should be followed when preparing large-scale and small-scale grids. Step 3: Using bonding, injection molding, and integrated molding processes, large-scale and small-scale grids are produced according to the designed multi-scale grid structure to ensure the dimensional accuracy of the grids and the stability of the structure; Step 4: Assemble the prepared large-scale and small-scale grids. During the assembly process, ensure that the connections between the grids are firm while maintaining the overall structure's permeability to allow for the flow of sewage and nutrients. Step 5: In order to improve the biocompatibility and anti-pollution performance of the carrier, biofilm covering and / or hydrophilization treatment are carried out to obtain a multi-scale gridded metazoan carrier; Step 6: Install the prepared multi-scale gridded biomass carrier into the sludge treatment tank at the rear of the biological treatment tank. Determine the installation position and fixing method according to the shape and size of the tank to ensure that the multi-scale gridded biomass carrier can remain stable during the sewage treatment process. Step 7: After the multi-scale gridded biomass carrier is installed, debugging and optimization work is carried out. By adjusting the grid spacing, layout and sewage flow rate, the multi-scale gridded biomass carrier is adapted to the actual needs of sewage treatment. At the same time, the sewage treatment effect and sludge production are monitored regularly. The carrier is adjusted and optimized according to the monitoring results to achieve the best sludge reduction effect.
[0009] In step 2, the three-dimensional porous topological characteristics of the natural habitat of metazoans in the freshwater ecosystem are simulated based on the biomimetic topological structure: the large-scale grid adopts a coral reef-like branch structure with a single branch diameter of 8-12 mm and a branch spacing of 1.5-2 times the width of the metazoan. The porosity is controlled at 65%-75% to ensure a balance between activity space and range restriction; the small-scale grid adopts a honeycomb microstructure with a sponge-like skeleton. The sponge-like fiber diameter is 50-200 μm and the side length of the honeycomb unit is 100-300 μm. It also has a gradient pore size distribution along the water flow direction, with the pore size at the inlet end being 15%-20% larger than that at the outlet end, providing a gradient growth microenvironment for protozoa.
[0010] In step 5, straw or bamboo fiber is boiled in a sodium hydroxide solution with a concentration of 1wt.%-3wt.% for 20-30 minutes, dried, and then pulverized into 80-120 mesh micro powder. A suspension with a concentration of 5wt.%-8wt.% is prepared using water as a solvent and sprayed evenly onto the surface of the carrier, with a coating thickness of 20-50μm. The carrier is then immersed in a chitosan aqueous solution with a concentration of 0.5wt.%-1wt.% and a pH of 5.5-6.0 for 10-15 minutes and air-dried to form a composite layer. The porous structure of the carrier enhances the attachment area for microorganisms, resulting in a multi-scale gridded biozoocarp carrier.
[0011] In step 5, the biofilm covering method is to introduce activated sludge into a multi-scale gridded biocarrier and aerate it for more than 24 hours; the hydrophilization treatment is to treat with ethylene oxide steam at a volume percentage concentration of 20% for 24 hours, and then wash with water until ethylene oxide is undetectable. The two methods can be used simultaneously or selectively.
[0012] In step 6, the sludge treatment tank is located at the rear end of the aerobic tank or at the rear end of the secondary sedimentation tank and is connected to the sludge discharge pipe.
[0013] The beneficial effects of this invention are: 1) Significant reduction in sludge volume: By constructing a multi-scale grid structure, this invention can precisely control the activity range of metazoans, thereby improving their utilization efficiency in wastewater treatment and achieving efficient sludge reduction. Compared with traditional sludge treatment methods, this invention has significant advantages in reducing sludge production, helping to lower the cost and difficulty of sludge treatment and disposal.
[0014] 2) Improve wastewater treatment efficiency: This invention improves wastewater treatment efficiency by constructing a stable food chain, promoting the cycling of nutrients and organic matter, and accelerating the degradation of organic matter in wastewater. The multi-scale grid design optimizes the distribution of biological populations, enhances biological activity, and further strengthens wastewater treatment.
[0015] 3) Environmental protection and sustainability: The mesh material used in this invention has good biocompatibility and biodegradability, is environmentally friendly, and will not cause secondary pollution. By reducing sludge production, this invention helps to reduce energy consumption and emissions in solid waste treatment and disposal, which is in line with the concept of sustainable development.
[0016] 4) Ease of operation and flexibility: The manufacturing process of this invention is relatively simple, making it easy to scale up production and application. The grid spacing, layout, and other parameters can be adjusted according to actual needs, offering strong flexibility and adaptability to meet the requirements of different wastewater treatment scenarios. Attached Figure Description
[0017] Figure 1 Scanning electron microscope images of multi-scale gridded metazoan carriers; Figure 2 Scanning electron microscope images of anaerobic bacteria and metazoans loaded onto a multi-scale meshed metazoan carrier; Figure 3 The treatment effect of sludge reduction before and after the use of multi-scale gridded bio-carrier is shown. Among them, (a) is the SS and VSS digestion rate after 60 days of continuous operation in Example 1, and (b) is the SS and VSS digestion rate after 60 days of continuous operation in Example 2. Detailed Implementation
[0018] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.
[0019] Example 1 A multi-scale gridded metazoan carrier for sludge reduction is prepared by the following steps: First, suitable materials are selected based on the requirements of the actual application. For large-scale grids, corrosion-resistant, wear-resistant carbon fiber filaments with certain strength and toughness are preferred as the main material; for small-scale grids, extruded microfiber bundles with good biocompatibility are selected as the main material. The structure of the multi-scale grid is designed according to the expected sludge treatment volume and the activity habits of the metazoans. Large-scale grids should ensure sufficient activity space for the metazoans while limiting their activity range; small-scale grids need to provide a suitable growth environment for the protozoans. The activity space for metazoans is designed to be 80 mesh, and the activity space for protozoans is designed to be 200 mesh.
[0020] Based on biomimetic topological structures, the three-dimensional porous topological characteristics of the natural habitat of metazoans in freshwater ecosystems are simulated: the large-scale grid adopts a coral reef-like branch structure with a single branch diameter of 8-12 mm and a branch spacing of 1.5-2 times the width of the metazoan. The porosity is controlled at 65%-75% to ensure a balance between activity space and range restriction; the small-scale grid adopts a honeycomb microstructure with a sponge-like skeleton. The sponge-like fiber diameter is 50-200 μm, the honeycomb unit side length is 100-300 μm, and the pore size is distributed in a gradient along the water flow direction. The pore size at the inlet end is 15%-20% larger than that at the outlet end, providing a gradient growth microenvironment for protozoa.
[0021] Using bonding, injection molding, and one-piece molding processes, large-scale and small-scale meshes (such as...) are fabricated according to the designed structure. Figure 1 (As shown). Ensure the dimensional accuracy and structural stability of the mesh; assemble the fabricated large-scale and small-scale meshes, ensuring strong connections between meshes while maintaining the overall structural permeability to allow for the flow of wastewater and nutrients; Straw or bamboo fiber is boiled in a 1wt.%-3wt.% sodium hydroxide solution for 20-30 minutes, dried, and then pulverized into 80-120 mesh powder. A 5wt.%-8wt.% suspension is prepared using water as a solvent and uniformly sprayed onto the surface of a carrier, with a coating thickness of 20-50 μm. The carrier is then immersed in a 0.5wt.%-1wt.% chitosan aqueous solution with a pH of 5.5-6.0 for 10-15 minutes and naturally air-dried to form a composite layer. The porous structure of the carrier enhances the attachment area for microorganisms, resulting in a multi-scale gridded biozoological carrier.
[0022] To improve the biocompatibility and antifouling performance of the carrier, it was first treated with 20% ethylene oxide vapor for 24 hours, followed by washing with water until ethylene oxide was undetectable. Then, activated sludge was introduced into the multi-scale gridded metazoan carrier and aerated for 24 hours to achieve biofilm coverage. Both methods were used simultaneously to enhance the carrier's adsorption capacity for microorganisms and its antifouling ability. Scanning electron microscope images of the resulting carriers loaded with protozoa and metazoans are shown below. Figure 2 As shown.
[0023] The fabricated multi-scale gridded bio-carrier is installed in the sludge treatment tank at the rear of the biological treatment tank. The sludge treatment tank is located behind the aerobic tank to ensure the carrier remains stable during wastewater treatment. After installation, commissioning and optimization are performed. By adjusting parameters such as grid spacing, layout, and wastewater flow rate, the carrier is adapted to the actual needs of wastewater treatment. Simultaneously, the wastewater treatment effect and sludge production are monitored regularly. Based on the monitoring results, the carrier is adjusted and optimized to achieve the best sludge reduction effect.
[0024] The sludge treatment tank filled with this multi-scale gridded bio-carrier is used to reduce the volume of aerobic activated sludge, such as... Figure 3 As shown in (a), after passing through the sludge treatment pond, the sludge dissolution rate increased significantly, with the dissolution rates of SS and VSS both increasing by 10% to 15%, achieving a good sludge reduction effect.
[0025] Example 2 A multi-scale gridded metazoan carrier for sludge reduction is proposed. First, carbon fiber filaments are selected as the main material for the large-scale grid, and extruded micron fiber bundles are selected as the main material for the small-scale grid. Based on the expected sludge treatment volume and the activity habits of metazoans, the structure of the multi-scale grid is designed. The large-scale grid provides 80 meshes of activity space for metazoans, and the small-scale grid provides 200 meshes of activity space for protozoans.
[0026] Based on biomimetic topological structure simulation, the three-dimensional porous topological characteristics of the natural habitat of metazoans in freshwater ecosystems are simulated: the large-scale grid adopts a coral reef-like branch structure with a single branch diameter of 8 mm and a branch spacing of 1.5 times the width of the metazoan, and the porosity is controlled at 65%; the small-scale grid adopts a honeycomb microstructure with a sponge-like skeleton, with a sponge-like fiber diameter of 50 μm and a honeycomb unit side length of 100 μm, and a gradient pore size distribution along the water flow direction, with the pore size at the inlet end being 15% larger than that at the outlet end, providing a gradient growth microenvironment for protozoa.
[0027] Large-scale and small-scale grids are combined in an orderly manner using bonding, injection molding, and one-piece molding to ensure the dimensional accuracy of the grids and the stability of the structure. The fabricated large-scale and small-scale grids are then assembled, ensuring that the connections between the grids are firm while maintaining the permeability of the overall structure to allow for the flow of wastewater and nutrients. Straw or bamboo fiber was boiled in a 1 wt.% sodium hydroxide solution for 20 minutes, dried, and pulverized into 80-mesh powder. A 5 wt.% suspension was prepared using water as a solvent and uniformly sprayed onto the surface of a carrier with a coating thickness of 20 μm. The carrier was then immersed in a 0.5 wt.% chitosan aqueous solution with a pH of 5.5 for 10 minutes and allowed to air dry to form a composite layer. The porous structure of the carrier enhanced the adhesion area for microorganisms, resulting in a multi-scale gridded biozoological carrier.
[0028] To improve the biocompatibility and antifouling performance of the carrier, it was treated with 20% ethylene oxide steam for 24 hours, followed by washing with water until ethylene oxide was undetectable. The fabricated multi-scale gridded biocarrier was then installed in the sludge treatment tank at the rear of the biological treatment tank. The appropriate installation location and fixing method were selected based on the shape and size of the tank. This sludge treatment tank is located at the rear of the aerobic tank. After the carrier installation was completed, commissioning and optimization were carried out. By adjusting parameters such as grid spacing, layout, and wastewater flow rate, the carrier was adapted to the actual needs of wastewater treatment. Simultaneously, the wastewater treatment effect and sludge production were monitored regularly. Based on the monitoring results, the carrier was adjusted and optimized to achieve the best sludge reduction effect.
[0029] The sludge treatment tank filled with this multi-scale gridded bio-carrier is used to reduce the volume of aerobic activated sludge, such as... Figure 3 As shown in (b), after passing through the sludge treatment pond, the sludge dissolution rate increased significantly, with the dissolution rates of SS and VSS both increasing by 10% to 15%, achieving a good sludge reduction effect.
[0030] Example 3 A multi-scale meshed metazoan carrier for sludge reduction is proposed. First, nylon mesh is selected as the main material for the large-scale mesh, and micro-nano-scale glass fiber is selected as the main material for the small-scale mesh. Based on the expected sludge treatment volume and the activity habits of metazoans, the structure of the multi-scale mesh is designed. The large-size mesh provides 100 meshes for the activity space of metazoans, and the small-size mesh provides 800 meshes for the activity space of protozoans.
[0031] Based on biomimetic topological structures, the three-dimensional porous topological characteristics of the natural habitat of metazoans in freshwater ecosystems are simulated: the large-scale grid adopts a coral reef-like branch structure with a single branch diameter of 12 mm and a branch spacing of twice the width of the metazoan, with a porosity controlled at 75%; the small-scale grid adopts a honeycomb microstructure with a sponge-like skeleton, with a sponge-like fiber diameter of 200 μm and a honeycomb unit side length of 300 μm, and a gradient pore size distribution along the water flow direction, with the inlet pore size being 20% larger than the outlet pore size, providing a gradient growth microenvironment for protozoa.
[0032] Large-scale and small-scale grids are combined in an orderly manner using bonding, injection molding, and one-piece molding to ensure the dimensional accuracy of the grids and the stability of the structure. The fabricated large-scale and small-scale grids are then assembled, ensuring that the connections between the grids are firm while maintaining the overall structure's permeability to allow for the flow of wastewater and nutrients.
[0033] Straw or bamboo fiber was boiled in a 3 wt.% sodium hydroxide solution for 30 minutes, dried, and pulverized into 120-mesh powder. A suspension with a concentration of 8 wt.% was prepared using water as a solvent and uniformly sprayed onto the surface of a carrier with a coating thickness of 50 μm. The carrier was then immersed in a 1 wt.% chitosan aqueous solution with a pH of 6.0 for 15 minutes and allowed to air dry to form a composite layer. The porous structure of the carrier enhanced the attachment area for microorganisms, resulting in a multi-scale gridded metazoan carrier.
[0034] To improve the biocompatibility and anti-fouling performance of the carrier, a biofilm covering method was adopted, and activated sludge was introduced into the multi-scale gridded bio-carrier and aerated for 36 hours. The prepared multi-scale gridded bio-carrier was installed in the sludge treatment tank at the rear of the biological treatment tank. Based on the shape and size of the tank, a suitable installation location and fixing method were selected. This sludge treatment tank is located at the rear of the secondary sedimentation tank and connected to the sludge discharge pipe. After the carrier installation was completed, commissioning and optimization were carried out. By adjusting parameters such as grid spacing, layout, and wastewater flow rate, the carrier was adapted to the actual needs of wastewater treatment. Simultaneously, the wastewater treatment effect and sludge production were monitored regularly. Based on the monitoring results, the carrier was adjusted and optimized to achieve the best sludge reduction effect.
[0035] Example 4 A multi-scale gridded metazoan carrier for sludge reduction is proposed. First, glass wool is selected as the main material for the large-scale grid, and extruded micron fiber bundles are selected as the main material for the small-scale grid. Based on the expected sludge treatment volume and the activity habits of metazoans, the structure of the multi-scale grid is designed. The large-scale grid provides 90 mesh for the activity space of metazoans, and the small-scale grid provides 600 mesh for the activity space of protozoans.
[0036] Based on biomimetic topological structures, the three-dimensional porous topological characteristics of the natural habitat of metazoans in freshwater ecosystems are simulated: the large-scale grid adopts a coral reef-like branch structure with a single branch diameter of 10 mm and a branch spacing of 1.75 times the width of the metazoan, with porosity controlled at 70% to ensure a balance between activity space and range restriction; the small-scale grid adopts a honeycomb microstructure with a sponge-like skeleton, with a sponge-like fiber diameter of 100 μm and a honeycomb unit side length of 200 μm, and a gradient pore size distribution along the water flow direction, with the inlet pore size being 17.5% larger than the outlet pore size, providing a gradient growth microenvironment for protozoa.
[0037] Large-scale and small-scale grids are combined in an orderly manner using bonding, injection molding, and one-piece molding to ensure the dimensional accuracy of the grids and the stability of the structure. The fabricated large-scale and small-scale grids are then assembled, ensuring that the connections between the grids are firm while maintaining the overall structure's permeability to allow for the flow of wastewater and nutrients.
[0038] Straw or bamboo fiber was boiled in a 2 wt.% sodium hydroxide solution for 22 minutes, dried, and pulverized into 100-mesh powder. A suspension with a concentration of 8 wt.% was prepared using water as a solvent and uniformly sprayed onto the surface of a carrier with a coating thickness of 30 μm. The carrier was then immersed in a 0.7 wt.% chitosan aqueous solution with a pH of 5.8 for 12 minutes and allowed to air dry to form a composite layer. The porous structure of the carrier enhanced the attachment area for microorganisms, resulting in a multi-scale gridded biozoological carrier.
[0039] To improve the biocompatibility and anti-fouling performance of the carrier, a biofilm covering method was adopted, and activated sludge was introduced into the multi-scale gridded bio-carrier and aerated for 48 hours. The prepared multi-scale gridded bio-carrier was installed in the sludge treatment tank at the rear of the biological treatment tank. Based on the shape and size of the tank, a suitable installation location and fixing method were selected. This sludge treatment tank is located at the rear of the aerobic tank. After the carrier installation was completed, commissioning and optimization were carried out. By adjusting parameters such as grid spacing, layout, and wastewater flow rate, the carrier was adapted to the actual needs of wastewater treatment. Simultaneously, the wastewater treatment effect and sludge production were monitored regularly. Based on the monitoring results, the carrier was adjusted and optimized to achieve the best sludge reduction effect.
[0040] Example 5 A multi-scale gridded metazoan carrier for sludge reduction is proposed. First, carbon fiber filaments are selected as the main material for the large-scale grid, and extruded micron fiber bundles are selected as the main material for the small-scale grid. Based on the expected sludge treatment volume and the activity habits of metazoans, the structure of the multi-scale grid is designed. The large-scale grid provides 100 meshes of activity space for metazoans, and the small-scale grid provides 400 meshes of activity space for protozoans.
[0041] Based on biomimetic topological structures, the three-dimensional porous topological characteristics of the natural habitat of metazoans in freshwater ecosystems are simulated: the large-scale grid adopts a coral reef-like branch structure with a single branch diameter of 9 mm and a branch spacing of twice the width of the metazoan, and the porosity is controlled at 68% to ensure a balance between activity space and range restriction; the small-scale grid adopts a honeycomb microstructure with a sponge-like skeleton, with a sponge-like fiber diameter of 150 μm and a honeycomb unit side length of 150 μm, and a gradient pore size distribution along the water flow direction, with the inlet pore size being 16% larger than the outlet pore size, providing a gradient growth microenvironment for protozoa.
[0042] Large-scale and small-scale grids are combined in an orderly manner using bonding, injection molding, and one-piece molding to ensure the dimensional accuracy of the grids and the stability of the structure. The fabricated large-scale and small-scale grids are then assembled, ensuring that the connections between the grids are firm while maintaining the overall structure's permeability to allow for the flow of wastewater and nutrients.
[0043] Straw or bamboo fiber was boiled in a 1.5 wt.% sodium hydroxide solution for 25 minutes, dried, and pulverized into 90-mesh powder. A 7 wt.% suspension was prepared using water as a solvent and uniformly sprayed onto the surface of a carrier with a coating thickness of 30 μm. The carrier was then immersed in a 0.75 wt.% chitosan aqueous solution at pH 6.0 for 15 minutes and allowed to air dry to form a composite layer. The porous structure of the carrier enhanced the adhesion area for microorganisms, resulting in a multi-scale gridded biozoological carrier.
[0044] To improve the biocompatibility and anti-fouling performance of the carrier, a biofilm covering method was adopted, and activated sludge was introduced into the multi-scale gridded post-biocarrier and aerated for 32 hours. The prepared multi-scale gridded post-biocarrier was installed in the sludge treatment tank at the rear of the biological treatment tank. Based on the shape and size of the tank, a suitable installation location and fixing method were selected. This sludge treatment tank is located at the rear of the secondary sedimentation tank and connected to the sludge discharge pipe. After the carrier installation was completed, commissioning and optimization were carried out. By adjusting parameters such as grid spacing, layout, and wastewater flow rate, the carrier was adapted to the actual needs of wastewater treatment. Simultaneously, the wastewater treatment effect and sludge production were monitored regularly. Based on the monitoring results, the carrier was adjusted and optimized to achieve the best sludge reduction effect.
[0045] The specific embodiments described above are only used to illustrate the spirit of the present invention. The scope of protection of the present invention is not limited thereto. For those skilled in the art, other embodiments can be easily made by means of changes, substitutions or modifications based on the technical content disclosed in this specification. All such other embodiments should be covered within the scope of protection of the present invention.
Claims
1. A method for preparing a multi-scale gridded metazoan carrier for sludge reduction, characterized in that, The steps are as follows: Step 1: Select the materials for making the carrier according to the application requirements; For large-scale grids, materials that are corrosion-resistant, wear-resistant, and have a certain strength and toughness are selected, such as carbon fiber, nylon mesh, and glass wool. For small-scale meshes, materials with good biocompatibility are selected, such as extruded micron-sized fiber bundles or micro / nano-sized glass fibers. Step 2: Design a multi-scale grid structure based on the expected sludge treatment volume and the activity habits of metazoans; Metazoans have an activity space of 80-100 mesh, while protozoa have an activity space of 200-800 mesh. The above principles should be followed when preparing large-scale and small-scale grids. Step 3: Using bonding, injection molding, and integrated molding processes, large-scale and small-scale grids are produced according to the designed multi-scale grid structure to ensure the dimensional accuracy of the grids and the stability of the structure; Step 4: Assemble the prepared large-scale and small-scale grids. During the assembly process, ensure that the connections between the grids are firm while maintaining the overall structure's permeability to allow for the flow of sewage and nutrients. Step 5: To improve the biocompatibility and anti-fouling performance of the carrier, biofilm covering and / or hydrophilic treatment are carried out; the porous structure of the carrier enhances the microbial attachment area, resulting in a multi-scale gridded post-biota carrier; Step 6: Install the prepared multi-scale gridded biomass carrier into the sludge treatment tank at the rear of the biological treatment tank. Determine the installation position and fixing method according to the shape and size of the tank to ensure that the multi-scale gridded biomass carrier can remain stable during the sewage treatment process. Step 7: After the multi-scale gridded biomass carrier is installed, debugging and optimization work is carried out. By adjusting the grid spacing, layout and sewage flow rate, the multi-scale gridded biomass carrier is adapted to the actual needs of sewage treatment. At the same time, the sewage treatment effect and sludge production are monitored regularly. The carrier is adjusted and optimized according to the monitoring results to achieve the best sludge reduction effect.
2. The method for preparing a multi-scale gridded metazoan carrier for sludge reduction according to claim 1, characterized in that, In step 2, the three-dimensional porous topological characteristics of the natural habitat of metazoans in the freshwater ecosystem are simulated based on the biomimetic topological structure: the large-scale grid adopts a coral reef-like branch structure with a single branch diameter of 8-12 mm and a branch spacing of 1.5-2 times the width of the metazoan. The porosity is controlled at 65%-75% to ensure a balance between activity space and range restriction; the small-scale grid adopts a honeycomb microstructure with a sponge-like skeleton. The sponge-like fiber diameter is 50-200 μm and the side length of the honeycomb unit is 100-300 μm. It also has a gradient pore size distribution along the water flow direction, with the pore size at the inlet end being 15%-20% larger than that at the outlet end, providing a gradient growth microenvironment for protozoa.
3. The method for preparing a multi-scale gridded metazoan carrier for sludge reduction according to claim 1, characterized in that, In step 5, the biofilm covering method is to introduce activated sludge into a multi-scale gridded biocarrier and aerate it for more than 24 hours; the hydrophilization treatment is to treat it with ethylene oxide steam at a volume percentage concentration of 20% for 24 hours, and then wash it with water until ethylene oxide is undetectable.
4. The method for preparing a multi-scale gridded metazoan carrier for sludge reduction according to claim 1, characterized in that, In step 5, straw or bamboo fiber is boiled in a sodium hydroxide solution with a concentration of 1wt.%-3wt.% for 20-30 minutes, dried, and then pulverized into 80-120 mesh micro powder. A suspension with a concentration of 5wt.%-8wt.% is prepared using water as a solvent and sprayed evenly onto the surface of the carrier, with a coating thickness of 20-50μm. The carrier is then immersed in a chitosan aqueous solution with a concentration of 0.5wt.%-1wt.% and a pH of 5.5-6.0 for 10-15 minutes and air-dried to form a composite layer. The porous structure of the carrier enhances the attachment area for microorganisms, resulting in a multi-scale gridded biozoocarp carrier.
5. The method for preparing a multi-scale gridded metazoan carrier for sludge reduction according to claim 1, characterized in that, In step 6, the sludge treatment tank is located at the rear end of the aerobic tank or at the rear end of the secondary sedimentation tank and is connected to the sludge discharge pipe.