Biological dredging device and open water composite dredging method

Abstract

The application discloses a biological dredging device and an open water composite dredging method, and belongs to the technical field of open water environment treatment. The biological dredging device comprises an aluminum alloy cuboid main frame, a fixed microorganism container coated with a fine steel wire mesh is arranged in the frame, and a fixed microorganism material with a carrier such as a volcanic rock and a membrane-hung aerobic bacteria is arranged in the frame; a float is hung on both sides of the frame, an aeration fan is arranged in the frame and is connected with an aeration pipe with a micro-nano aeration head, a push flow driving module and a solar power supply module can be additionally arranged; according to the composite dredging method, after the initial measurement of a silt layer, biological dredging is performed to a preset switching depth by using the biological dredging device, then a mechanical dredging device is selected according to water body parameters to dig to a design depth, and the design depth is confirmed by subtracting the biological dredging amount from the total dredging amount. The application is suitable for the dredging of open water bodies such as rivers, lakes, aquaculture tail water areas and the like, and the dredging efficiency is significantly improved and the cost is reduced through the complementary advantages of biological dredging and mechanical dredging in time and space.

Description

Technical Field

[0001] This invention belongs to the technical field of water environment management of open water bodies, specifically involving a biological dredging device and a composite dredging method for open water bodies, which is applicable to silt removal and water environment restoration operations in open water bodies such as small and medium-sized rivers, lakes, and contiguous aquaculture tailwater areas. Background Technology

[0002] Siltation in open water bodies is a major cause of water quality deterioration and ecological degradation, and dredging is one of the core procedures in water environment management. Currently, the main dredging methods for open water bodies in the engineering field are mechanical dredging, supplemented by a small amount of biological dredging (microbial dredging), which is classified as an ecological restoration method. Both types of dredging methods have obvious technical limitations.

[0003] Common mechanical dredging techniques include: for large bodies of water, dry dredging with excavators during the dry season, wet dredging with excavators on carrier platforms, dredging by dredging vessels, and zoned dredging with cofferdams; for small and medium-sized bodies of water, methods such as direct excavation with small excavators along the bank or natural drying on the bank followed by removal are commonly used. The advantages of these mechanical dredging methods are their mature technology, relatively simple operation, and high dredging efficiency in the short term. However, mechanical dredging also has significant drawbacks: firstly, its direct cost is high, with market prices typically ranging from 30-80 yuan / m³. 3 (Below the water surface) is easily affected by factors such as silt properties, construction conditions, transportation distance, and environmental protection requirements, which can increase its concentration. Secondly, in the early stages of dredging, the upper silt (usually a 0-30cm floating silt layer) has an extremely high water content (>98%) and is in a fluid state. Mechanical dredging at this stage is more about removing water than effectively dredging, and it can easily lead to the diffusion of bottom sediment, resulting in low dredging efficiency. In addition, traditional dredging thinking has been entrenched for a long time, rarely paying attention to the changes in the mud-water interface and silt layer structure over time during the entire dredging process, as well as the efficiency differences of different dredging processes at different silt layers, and lacking research on optimizing the efficiency of the entire dredging process.

[0004] Another dredging method is biological dredging, which mainly reduces silt through microbial degradation. Engineering practice shows that biological dredging exhibits good dredging effects in the early stages (floating silt layer), and under suitable conditions, it can decompose silt with a thickness of more than 0.3m per week, with treatment costs far lower than mechanical dredging. However, biological dredging is often regarded only as a means of ecological restoration in the engineering field, and its core role in the overall dredging strategy is overlooked. Furthermore, in the later stages of biological dredging, as the silt layer deepens, the water content decreases (the lower silt layer is about 85%), particle compaction increases, and the pollution load relatively decreases, the efficiency of microbial silt removal significantly decreases or even becomes ineffective, making it impossible to complete the entire dredging operation.

[0005] In summary, among existing open water dredging technologies, mechanical dredging and biological dredging have complementary advantages and disadvantages. However, the industry has not fully explored this complementarity, nor has it found an efficient switching point between the two methods. There is a lack of composite dredging methods that can integrate the advantages of both. Furthermore, existing biological dredging lacks dedicated integrated equipment; it often combines scattered aeration devices with microbial addition methods, resulting in insufficient aerobic environment creation, inadequate contact between microorganisms and sludge, and limited operational scope, thus failing to fully realize the effectiveness of biological dredging. To address these issues, there is an urgent need to develop a dedicated biological dredging device and construct a mechanical-biological composite dredging method based on this device to achieve efficient and low-cost open water dredging operations. Summary of the Invention

[0006] This invention addresses the limitations of existing open water dredging technologies that rely on separate mechanical and biological dredging operations, as well as the lack of dedicated integrated equipment for biological dredging. It provides a biological dredging device and a combined dredging method for open water bodies. The device integrates aeration and oxygenation with the immobilization of microorganisms to decompose sludge, making it suitable for open water bodies of varying sizes. Furthermore, based on this device, a combined dredging method is constructed, fully leveraging the complementarity of mechanical and biological dredging to solve the technical problems of low efficiency and high cost associated with single dredging methods, thereby maximizing the efficiency and minimizing the cost of open water body dredging.

[0007] The primary objective of this invention is to provide a biological dredging device, employing the following technical solution: A biological dredging device includes: a main frame, a container for carrying microorganisms, a material for carrying microorganisms, floats, and an aeration device. The main frame is a rectangular frame. The container for carrying microorganisms is fixedly installed inside the main frame. The container is made of welded aluminum alloy tubing and covered with fine steel wire mesh. The material for carrying microorganisms is filled inside the container. Floats are symmetrically attached to both sides of the main frame to provide buoyancy. The aeration device includes an aeration fan, a guide pipe, fixing bolts, an aeration pipe, and an aeration head. The aeration fan is built into the float. The aeration pipe is connected to the aeration fan through the guide pipe and fixed to the main frame by the fixing bolts. The aeration head is located at the end of the aeration pipe away from the fixing bolts. The aeration head is placed below the water surface and arranged in a counter-facing, side-opening manner.

[0008] Preferably, the device also includes a propulsion drive module, which includes an impeller propulsion fan and an impeller thruster. The impeller propulsion fan is located inside a float on one side, and the impeller thruster is connected to the outside of the main frame. The impeller thruster is connected to the impeller propulsion fan to drive the device to move on the water surface.

[0009] Preferably, a power supply module is also included, which is an external power source or a solar panel. The solar panel is fixed above the main frame and is used to supply power to the aeration blower and / or the impeller propulsion blower.

[0010] Preferably, the immobilized microbial material is a granular structure loaded with aerobic microbial flora, wherein the aerobic microbial flora is selected from one or more of photosynthetic bacteria, nitrifying bacteria, denitrifying bacteria, and Bacillus. The immobilized microbial material is formed by soaking a mixture of aerobic microbial communities in sintered volcanic rock, zeolite particles, clay, or diatomaceous earth to form a biofilm.

[0011] Preferably, the main frame and the microbial carrier container are both made of welded aluminum alloy tubes, and the microbial carrier container is covered with fine steel wire mesh; the float is made of strong and tough high molecular weight polyethylene; and the aeration head is a micro-nano aeration head.

[0012] The second objective of this invention is to provide a composite dredging method for open water bodies, which employs the aforementioned biological dredging equipment in conjunction with mechanical dredging equipment, and includes the following steps: S1. Initial measurement and record of silt layer: The thickness of the silt layer in the target open water body is monitored and recorded at multiple points to determine the initial silt layer thickness benchmark. S2, Biological dredging stage: The biological dredging equipment is deployed on site and started to carry out biological dredging. An aerobic environment is created through micro-nano aeration, and the aerobic microbial community in the immobilized microbial material is used to dissolve the sludge. During the dredging process, the thickness of the sludge layer is measured at multiple points and at multiple time periods under static water surface conditions until the thickness of the sludge layer drops to the preset switching depth. S3. Switching between dredging methods: Biological dredging equipment is phased out, and mechanical dredging equipment is selected to be used based on the surface area, length, width, topography, flow pattern, water depth, and intended use of the target open water body. S4. Mechanical dredging stage: Start the mechanical dredging equipment and dredge to the designed dredging depth. The dredging depth is confirmed by subtracting the biological dredging volume from the designed total dredging volume. S5. Dredging Completed: Once the mechanical dredging equipment reaches the designed dredging depth, the dredging operation is stopped, completing the entire composite dredging process.

[0013] Preferably, the preset switching depth is 50cm below the surface of the silt layer, or a thickness value within the range of 30cm-60cm of the silt layer, determined according to the water type and pollution characteristics.

[0014] Preferably, in step S2, the surface area of ​​the target open water body is ≤2000m². 2At this time, the biological dredging equipment adopts fixed-point aeration or manual traction for mobile aeration, without adding a propulsion drive module; when the surface area of ​​the target open water body is >2000m² 2 At the same time, the biological dredging equipment is equipped with a propulsion drive module, which drives the equipment to move within the working area through an impeller propulsion fan and an impeller propeller, so as to achieve full-surface aeration and oxygenation and biological decomposition.

[0015] Preferably, in steps S1 and S2, when the target water body is a small to medium-sized water body, i.e., the water surface area is <10000m² 2 The thickness of the silt layer was recorded and remeasured using a ruler; when the target water body is a large water body, i.e., the water surface area is ≥10000m² 2 Add real-time monitoring equipment for changes in the silt layer. The monitoring equipment is one or more of the following: piston sampler, in-situ stratification sampling equipment, portable depth sounder, sludge interface meter, underwater robot, or sonar navigation system.

[0016] Preferably, in step S3, the mechanical dredging equipment is selected based on the width, depth, and topography of the open water body: when the target water body's surface width is <20m, dry dredging is performed directly by excavators during the dry season or wet dredging is performed by excavators on a carrier platform; when the target water body's surface width is >50m, dredging is performed in sections with cofferdams during the dry season; when the target water body's depth is >5m, grab bucket dredging vessels or artillery suction dredging vessels are used; if the target water body is large in length, width, and depth and the project schedule is tight, trailing suction hopper dredging vessels are used.

[0017] The beneficial effects of this invention are: (1) Integrated, multifunctional, and highly adaptable biological dredging equipment: The biological dredging equipment of this invention organically combines micro-nano aeration and oxygenation with the decomposition of sludge by immobilized microorganisms, enabling a single device to complete two core biological dredging processes, thus solving the problems of fragmented and poorly coordinated existing biological dredging equipment. The immobilized microbial material is made of carriers such as volcanic rock and zeolite, which greatly improves the contact efficiency between microorganisms and suspended particles in sludge, and ensures long-term retention of microorganisms; the equipment can be flexibly equipped with a flow-driving module and a solar power supply module, adapting to small water areas below 2000m² and large water areas above 2000m², and also suitable for operation scenarios with or without external power supply. At the same time, lightweight materials such as aluminum alloy and strong and tough high-molecular polyethylene are used to ensure the floating stability and easy mobility of the equipment.

[0018] (2) The composite dredging method fully leverages the complementarity of mechanical and biological dredging: This invention for the first time clearly defines the efficient switching point between mechanical and biological dredging as the silt layer of 30-60cm. It utilizes the efficient dissolution advantage of biological dredging in the initial floating mud layer and transition layer to solve the problem of "clear water generating mud" and low efficiency in the early stage of mechanical dredging. It utilizes the efficient excavation advantage of mechanical dredging in the middle and lower layers of silt to solve the problem of a sharp drop in efficiency in the later stage of biological dredging, thereby maximizing the dredging efficiency throughout the process and increasing the dredging volume by a certain amount compared to simple biological dredging or simple mechanical dredging in the same amount of time.

[0019] (3) Dredging costs are significantly reduced and economic benefits are significant: The biological dredging stage of this invention only generates equipment power consumption and has no sludge transportation and disposal costs, which can significantly reduce the initial dredging costs; the mechanical dredging stage only targets the middle and lower layers of sludge, reducing the amount of mechanical dredging work and working time, and further reducing the overall cost.

[0020] (4) The dredging process is precise and controllable, reducing secondary pollution of water bodies: The composite dredging method of the present invention monitors the thickness of the silt layer at multiple points and at multiple time periods to precisely control the switching depth of biological dredging; the mechanical dredging depth is confirmed by back-calculation of the difference between the designed total dredging volume and the biological dredging volume, so as to achieve precise control of the dredging volume; at the same time, biological dredging dissolves silt in situ, avoiding the problem of bottom sediment diffusion in the early stage of mechanical dredging, reducing secondary pollution of water bodies during the dredging process, and taking into account both dredging effect and water body ecological protection.

[0021] (5) Simple process, convenient operation, and wide engineering applicability: The composite dredging method of the present invention has a clear process, the biological dredging equipment does not require complicated operation, and can be used for fixed-point or mobile operations. The mechanical dredging equipment is selected to fit the existing engineering process, and it is easy for technicians to learn. The method is applicable to various open water bodies such as small and medium-sized rivers, lakes, and contiguous aquaculture tailwater areas. The equipment and process can be flexibly adjusted according to the water area, water depth, and terrain, and the engineering promotion is strong. Attached Figure Description

[0022] For ease of explanation, the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0023] Figure 1 This is a schematic diagram of the biological dredging equipment according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the biological dredging equipment according to Embodiment 2 of the present invention; Figure 3 This illustrates the changes in dredging efficiency over time for biological and mechanical dredging in Embodiment 3 of the present invention. Figure 4 This refers to the amount of silt removed by biological dredging in Example 3 of the present invention; Figure 5 This refers to the amount of silt removed by mechanical dredging in Embodiment 3 of the present invention; Figure 6 The amount of silt removed is the amount removed by biological silt removal and mechanical silt removal in Embodiment 3 of the present invention.

[0024] In the picture: 1-Main frame; 2-Impregnated microbial container; 3-Impregnated microbial material; 4-Float; 5-Aeration blower; 6-Conduit; 7-Fixing bolt; 8-Aeration pipe; 9-Aeration head; 10-Impeller propulsion fan; 11-Impeller propeller; 12-Solar panel. Detailed Implementation

[0025] The following are specific embodiments of the present invention described in conjunction with the accompanying drawings, further illustrating the technical solutions of the present invention. However, the present invention is not limited to these embodiments. Specific details, such as particular configurations and components, are provided in the following description merely to aid in a comprehensive understanding of the embodiments of the present invention. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Furthermore, for clarity and brevity, descriptions of known functions and structures have been omitted.

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0027] Example 1: Biological sludge removal equipment like Figure 1 As shown, this embodiment provides a biological dredging device, including a main frame 1, which is a cuboid frame welded from aluminum alloy square tubes (e.g., 1-2m in length, 1cm x 1cm in diameter). A microbial carrier container 2 is fixedly installed inside the main frame 1. This container is also made of welded aluminum alloy tubes and covered with fine wire mesh to form a mesh container. The container is filled with microbial carrier material 3. The microbial carrier material 3 can be made of volcanic rock, zeolite particles, or sintered clay and diatomaceous earth as a carrier, and is immersed in a mixed solution containing one or more aerobic microbial communities such as photosynthetic bacteria, nitrifying bacteria, denitrifying bacteria, and Bacillus, forming a granular structure after biofilm formation. Floats 4 are symmetrically attached to both sides of the main frame 1. The floats 4 are made of strong and tough high-molecular-weight polyethylene material to provide buoyancy for the entire device.

[0028] The aeration device includes an aeration blower 5 built into the float 4, and an aeration pipe 8 connected to the aeration blower 5 via a conduit 6. The aeration pipe 8 is fixed to the main frame 1 by fixing bolts 7. An aeration head 9 is installed at the end of the aeration pipe 8 away from the fixing bolts 7 (i.e., the underwater end). The aeration head 9 is a micro-nano aeration head and is placed underwater. The aeration heads 9 are arranged in a counter-direction configuration, that is, the aeration heads 9 on both sides of the device are arranged in opposite directions to create a uniform and stable aerobic environment below and around the container carrying the microorganisms.

[0029] The equipment also includes a power supply module, which can be powered by an external power source or by fixing a solar panel 12 on top of the main frame 1 to power the aeration blower 5.

[0030] Example 2: Biological dredging equipment with flow propulsion function When the surface area of ​​the target water body is greater than 2000 m², a flow propulsion module is added to the equipment described in Example 1. For example... Figure 2 As shown, the propulsion drive module includes an impeller propulsion fan 10 and an impeller thruster 11. The impeller propulsion fan 10 is installed inside one of the floats 4 (e.g., the right float). The impeller thruster 11 is connected to the outside of the main frame 1 and is connected to the impeller propulsion fan 10 through a transmission mechanism. After the impeller propulsion fan 10 is started, it drives the impeller thruster 11 to work, thereby propelling the entire biological dredging equipment to move on the water surface, achieving comprehensive aeration and biodegradation within the working area, and improving the efficiency of biological dredging. However, it is necessary to ensure the weight balance of the aeration fan 5 and the impeller propulsion fan 10 built into the two floats 4 to ensure the stability of the entire equipment. At this time, the power supply module (such as the solar panel 12) needs to supply power to both the aeration fan 5 and the impeller propulsion fan 10 simultaneously.

[0031] Example 3: Composite Dredging Method for Open Water Bodies This embodiment takes a small to medium-sized river dredging project with a water surface area of ​​less than 10,000 m² as an example to illustrate the composite dredging method provided by the present invention.

[0032] S1. Initial measurement record of silt layer: Use a ruler to select multiple monitoring points in the river channel, measure and record the initial silt layer thickness at each point, and determine the average silt thickness benchmark. S2, Biological Desilting Stage: The biological dredging equipment with flow-driving function from Example 2 is placed in the river channel and started. The aeration blower 5 operates, and the micro-nano aeration heads 9 release micro-nano bubbles to the bottom of the water, creating an aerobic environment. Under aerobic conditions, the aerobic microbial community on the immobilized microbial material 3 efficiently degrades the upper fluidized sludge layer. Simultaneously, the impeller-driven flow-driving blower 10 drives the equipment to move slowly within the river channel, achieving aeration and biological treatment throughout the entire area. During this process, the sludge layer thickness is periodically (e.g., daily) measured using a ruler in a stationary state until the sludge layer thickness decreases to 50 cm below the sludge layer surface. S3. Switching between dredging methods: Biological dredging equipment is phased out, and mechanical dredging equipment is selected to enter the site based on the width and depth of the target water body; in this example, a small excavator is used to carry out dry dredging directly on the bank during the dry season.

[0033] S4. Mechanical dredging stage: Start the mechanical dredging equipment and dredge to the designed dredging depth. The dredging depth is confirmed by subtracting the biological dredging volume (50cm) from the designed total dredging volume. S5. Dredging Completed: Once the mechanical dredging equipment has reached the designed dredging depth, the dredging operation is stopped, a comprehensive acceptance test is conducted, and the dredging process is completed.

[0034] See Figures 3-6 This graph shows the change in dredging efficiency over time for both biological and mechanical dredging methods. The horizontal axis represents dredging time, and the vertical axis represents dredging efficiency. The product of time and efficiency is the dredging effectiveness, or dredging volume, represented by the shaded area. Figure 6 It can be seen that the composite dredging mode determined by the present invention is significantly better than simple biological dredging and mechanical dredging. In the same amount of time, the composite dredging mode removes more dredging volume S1 than simple biological dredging and more dredging volume S2 than simple mechanical dredging.

[0035] Implementation results: Considering the dredging time, and referring to a case study of a biological dredging project in a river in Guangzhou, the bottom mud layer of the river dropped by 30cm after 3 days of dredging, essentially eliminating the floating mud layer. Theoretically, the dredging efficiency of the transition layer should not be less than 50% of that of the floating mud layer. Based on this, it is estimated that it would take approximately 7 days to reach a 50cm mud layer, with a dredging area of ​​approximately 2000 m². 2 The total dredging volume is approximately 1000m³. 3 If the excavator direct excavation method is used in mechanical dredging, according to engineering experience, it generally takes more than 10 days for a single excavator, not including the time for transporting and disposing of the sludge, which is difficult to estimate.

[0036] Considering dredging costs, the main cost of biological dredging over 7 days is the electricity consumption of the biological dredging equipment. Assuming full-load 24-hour operation per day (168 hours of work), with a single unit powering 2KW, the total electricity consumption is 336 kWh, which, at 0.6 yuan / kWh, amounts to approximately 201.6 yuan. In contrast, manual dredging methods, represented by small excavators, cost 50 yuan / m³. 3 1000 m³ of silt was dredged. 3 The total cost would then be approximately 50,000 yuan.

[0037] The silt layer is over 50cm thick, mainly consisting of the old soil layer at the bottom of the silt layer. The pollution load is low, and the silt particles are highly compacted. Using biological dredging methods would significantly reduce the efficiency of silt removal, which gradually approaches zero over time. At this point, using small-scale mechanical dredging would still yield a daily silt removal volume of 60-90 m³. 3 Its dredging efficiency per unit time is significantly higher than that of biological dredging.

[0038] In summary, for small and medium-sized open water bodies, there are significant differences in dredging time and cost between biological dredging and small-scale mechanical dredging: within a silt layer of less than 50cm, biological dredging is superior to small-scale mechanical dredging; however, above a silt layer of 50cm, mechanical dredging is superior to biological dredging. Therefore, a novel combined dredging model, employing initial biological dredging followed by mechanical dredging, can effectively utilize the advantages and disadvantages of both methods to achieve optimal dredging efficiency.

[0039] Example 4: Dredging method for large open water bodies For large lakes with a surface area greater than 10,000 m², the method is as follows: In steps S1 and S2, a sonar navigation system or underwater robot is used to monitor changes in the silt layer thickness in real time, accurately determining when the biological dredging stage reaches the switching depth. In step S3, based on factors such as lake width and water depth, a cutter suction dredging vessel is selected as the mechanical dredging equipment to carry out subsequent silt dredging operations.

[0040] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0041] In the description of this application, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

Claims

1. A biological dredging device, characterized in that, include: The main frame (1) is constructed as a cuboid frame; The microbial container (2) is fixedly installed inside the main frame (1). The microbial container (2) is made of aluminum alloy tube welded together and covered with fine steel wire mesh on the outside. Immobilized microbial material (3), wherein the immobilized microbial material (3) is filled into the immobilized microbial container (2); Floats (4) are symmetrically attached to both sides of the main frame (1) to provide buoyancy for the main frame (1); An aeration device is provided, comprising an aeration blower (5), a guide pipe (6), a fixing bolt (7), an aeration pipe (8), and an aeration head (9). The aeration blower (5) is built into a float (4). The aeration pipe (8) is connected to the aeration blower (5) through the guide pipe (6) and is fixed to the main frame (1) by the fixing bolt (7). The aeration head (9) is located at the end of the aeration pipe (8) away from the fixing bolt (7). The aeration head (9) is placed below the water surface and is arranged in a counter-side opening manner.

2. The biological dredging device according to claim 1, characterized in that, It also includes a propulsion drive module, which includes an impeller propulsion fan (10) and an impeller thruster (11). The impeller propulsion fan (10) is located inside a float (4) on one side, and the impeller thruster (11) is connected to the outside of the main frame (1). The impeller thruster (11) is connected to the impeller propulsion fan (10) to drive the equipment to move on the water surface.

3. The biological dredging device according to claim 2, characterized in that, It also includes a power supply module, which is an external power source or a solar panel (12). The solar panel (12) is fixed above the main frame (1) and is used to supply power to the aeration blower (5) and / or the impeller propulsion blower (10).

4. The biological dredging device according to claim 1, characterized in that, The immobilized microbial material (3) is a granular structure loaded with aerobic microbial communities, which are selected from one or more of photosynthetic bacteria, nitrifying bacteria, denitrifying bacteria, and Bacillus. The immobilized microbial material (3) is formed by soaking a mixture of aerobic microbial communities in volcanic rock, zeolite particles or clay and diatomaceous earth sintered bodies and then attaching a biofilm.

5. The biological dredging device according to claim 1, characterized in that, The main frame (1) and the microbial container (2) are both made of aluminum alloy tubes welded together. The microbial container (2) is covered with fine steel wire mesh. The float (4) is made of strong and tough high molecular weight polyethylene. The aeration head (9) is a micro-nano aeration head.

6. A composite dredging method for open water bodies, implemented using the biological dredging equipment as described in any one of claims 1-5 in conjunction with mechanical dredging equipment, characterized in that, Includes the following steps: S1. Initial measurement and record of silt layer: The thickness of the silt layer in the target open water body is monitored and recorded at multiple points to determine the initial silt layer thickness benchmark. S2, biological dredging stage: biological dredging equipment is deployed and started for biological dredging. An aerobic environment is created through micro-nano aeration, and the aerobic microbial community in the solidified microbial material (3) is used to dissolve the sludge. During the dredging process, the thickness of the sludge layer is re-measured at multiple points and at multiple times under the static water surface state until the thickness of the sludge layer drops to the preset switching depth. S3. Switching between dredging methods: Biological dredging equipment is phased out, and mechanical dredging equipment is selected to be used based on the surface area, length, width, topography, flow pattern, water depth, and intended use of the target open water body. S4. Mechanical dredging stage: Start the mechanical dredging equipment and dredge to the designed dredging depth. The dredging depth is confirmed by subtracting the biological dredging volume from the designed total dredging volume. S5. Dredging Completed: Once the mechanical dredging equipment reaches the designed dredging depth, the dredging operation is stopped, completing the entire composite dredging process.

7. The method for composite dredging of open water bodies according to claim 6, characterized in that, The preset switching depth is 50cm below the surface of the silt layer, or a thickness value within the range of 30cm-60cm of the silt layer, determined according to the water type and pollution characteristics.

8. A composite dredging method for open water bodies according to claim 6, characterized in that, In step S2, when the surface area of ​​the target open water body is ≤2000m² 2 At that time, the biological dredging equipment adopts fixed-point aeration or manual traction to move the aeration, without adding a push-flow drive module; When the surface area of ​​the target open water body is >2000m² 2 At the same time, the biological dredging equipment is equipped with a propulsion drive module, which drives the equipment to move within the working area through the impeller propulsion fan (10) and the impeller propeller (11) to achieve full-surface aeration and oxygenation and biological decomposition.

9. A composite dredging method for open water bodies according to claim 6, characterized in that, In steps S1 and S2, when the target water body is a small to medium-sized water body, i.e., the water surface area is <10000m² 2 The thickness of the silt layer was recorded and remeasured using a ruler; When the target water body is a large water body, i.e., the water surface area is ≥10000m² 2 Add real-time monitoring equipment for changes in the silt layer. The monitoring equipment is one or more of the following: piston sampler, in-situ stratification sampling equipment, portable depth sounder, sludge interface meter, underwater robot, or sonar navigation system.

10. A composite dredging method for open water bodies according to claim 6, characterized in that, In step S3, the mechanical dredging equipment is selected based on the width, depth, and topography of the open water body: When the width of the target water body is less than 20m, dry cleaning with an excavator during the dry season or wet cleaning with a carrier platform excavator is adopted. When the width of the target water body is greater than 50m, the dry season is used for zoned cofferdam construction and dredging. When the target water body is deeper than 5m, a grab bucket dredging vessel or a cutter suction dredging vessel shall be used. If the target water body is large in length, width and depth and the project schedule is tight, a trailing suction hopper dredging vessel will be used.

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