Water-lifting aeration coupled with inorganic electron donor enhanced biological water quality improvement device

Abstract

This invention relates to the field of water treatment technology, specifically to a device for enhancing biological water quality improvement using a pumped aeration coupled with an inorganic electron donor. The device includes an anchoring unit, a pumped aeration unit, a guide tube, and a bioreactor unit. The pumped aeration unit intermittently releases high-pressure gas to generate an upward gas-liquid mixture. A preset distance between the bioreactor and the guide tube provides hydraulic buffering, precisely controlling the flow velocity to ensure complete fluidization of the biological packing material without impact damage. The bioreactor is connected to a first steel chain via a flexible connector, further mitigating vibrations from water flow fluctuations and airflow impacts. This solves the problem of existing biological packing materials being broken by high-speed airflow impacts over long periods. Simultaneously, the coaxial reference design avoids water flow deviation, ensuring uniform delivery of dissolved oxygen, pollutants, and indigenous microorganisms. This allows the oxygenation and mixing functions of the pumped aeration unit and the vertical circulation function of the bioreactor to work synergistically, achieving continuous in-situ improvement of reservoir water quality.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, specifically to a device for enhancing biological water quality improvement by coupling water pumping aeration with inorganic electron donors. Background Technology

[0002] As important drinking water sources, reservoirs generally suffer from slow water flow and weak self-purification capacity. Pollutants such as nitrogen, phosphorus, and organic matter tend to accumulate in the water, leading to eutrophication and algal blooms. This, in turn, causes a series of water quality problems such as abnormally high pH levels, excessive levels of odor substances and organic matter, seriously threatening drinking water safety.

[0003] Aerobic denitrifying bacteria, with their unique metabolic characteristics, can utilize electrons generated from the decomposition of organic matter to convert nitrate nitrogen into nitrogen gas, thereby reducing total nitrogen. Simultaneously, they absorb phosphorus from the water for their own growth and reproduction, thus simultaneously completing nitrogen removal, phosphorus removal, and organic matter degradation. This is considered an effective technical approach for controlling and improving water quality in lakes and reservoirs. However, source water bodies generally have low organic carbon levels, typically below 6-10 mg / L. This severe shortage of carbon and electron donors makes it difficult for aerobic denitrifying bacteria to effectively colonize and perform their biological functions, greatly limiting the practical application of this technology.

[0004] Among existing water quality improvement technologies for reservoirs, the pumped aeration mixed oxygenation technology is widely used. It primarily addresses the issues of oxygen deficiency in the bottom water and excessive algae growth on the surface by raising the bottom water to the surface. However, for slightly polluted water bodies with high nitrogen, phosphorus, and organic matter content, this technology only achieves oxygenation and mixing, failing to effectively degrade pollutants, resulting in limited water quality improvement. To overcome this deficiency, Chinese invention patent CN108569780B discloses a bubble-cutting biological contact oxidation enhanced pumped aeration water quality improvement device. This patent combines pumped aeration with biological contact oxidation, utilizing oxygen-rich water to contact and degrade pollutants with microorganisms on the biological packing material. However, this solution still has significant shortcomings: firstly, it does not solve the core problem of insufficient carbon source in the water source, and the actual reduction effect on nitrogen, phosphorus, and organic matter remains limited; secondly, the air and water flow velocities at the outlet of the guide tube in deep-water reservoirs are extremely high. Long-term high-speed impact can damage the packing material in the directly connected biological contact oxidation device, making it difficult for microorganisms to stably accumulate and proliferate, thus hindering their continuous pollution removal function. Summary of the Invention

[0005] This invention provides a water pumping aeration coupled with inorganic electron donor to enhance biological water quality improvement device, in order to solve the problem that existing water quality improvement devices cannot simultaneously solve the problems of insufficient carbon source in water source and susceptibility of biological packing material to impact damage.

[0006] The water pumping aeration coupled with inorganic electron donors to enhance biological water quality improvement device of the present invention adopts the following technical solution: A device for enhancing biological water quality improvement by coupling water pumping and aeration with inorganic electron donors includes an anchoring unit, a water pumping and aeration unit, a guide tube, and a bioreactor unit.

[0007] The anchoring unit is fixed to the bottom of the water; a first steel chain is provided on the anchoring unit, and a floating component is provided at the upper end of the first steel chain, which always floats on the water surface; the water-lifting aeration unit is connected to the anchoring unit through a second steel chain, and the water-lifting aeration unit is coaxially sleeved on the outside of the first steel chain, and the water-lifting aeration unit is used to generate an upward gas-liquid mixture flow underwater; the guide tube is fixedly set above the water-lifting aeration unit, and the guide tube is used to guide the upward gas-liquid mixture flow in a vertical direction; the bioreactor unit is a cylindrical chamber, which is used to accommodate biological packing and provide water purification reaction space, and the chamber is connected to the first steel chain through a flexible connector; the chamber and the top of the guide tube are coaxially spaced, and the distance between the chamber and the guide tube is determined by computational fluid dynamics simulation to ensure that the biological packing is in a fully fluidized state and is not damaged by the high-speed upward gas-liquid mixture flow.

[0008] Furthermore, the biological packing material has a double-layer spherical structure, comprising an inner spherical shell and an outer spherical shell, both of which are porous mesh structures; the inner spherical shell is fixed to the center of the outer spherical shell by a support member; the diameter ratio of the inner spherical shell to the outer spherical shell is 1:1.5-1:2.5.

[0009] Furthermore, the inner spherical shell is filled with granular inorganic electron donors, which provide electrons for microbial metabolism; a soft biological carrier is filled between the inner and outer spherical shells, which provides attachment and growth sites for microorganisms; and aquatic native functional microorganisms are attached to the soft biological carrier.

[0010] Furthermore, the inorganic electron donor is located in a micro-oxygen environment formed inside the inner spherical shell. This micro-oxygen environment is used to control the slow release rate of the inorganic electron donor, enabling it to continuously and slowly release electrons to provide the electron donors required for the metabolism of aerobic denitrifying bacteria.

[0011] Furthermore, the inorganic electron donor includes at least one of low-cost inorganic metal elements or compounds that can provide electrons, such as sponge iron or pyrite, which have no adverse effect on water quality.

[0012] Furthermore, the soft biological carrier is at least one of polyurethane sponge, polyvinyl alcohol sponge, polypropylene fiber, etc.

[0013] Furthermore, the cabin extends through both its upper and lower ends, and both ends of the cabin are provided with perforated partitions; a central cylinder is coaxially fixed inside the cabin, the central cylinder passes through the perforated partitions, and the first steel chain passes through the central cylinder; multiple supporting ribs are provided between the inner wall of the cabin and the outer wall of the central cylinder, the multiple supporting ribs are evenly distributed in the circumferential direction of the cabin, and the multiple supporting ribs divide the interior of the cabin into multiple filling chambers.

[0014] Furthermore, the distance between the cabin and the guide tube is determined based on the fact that the maximum flow velocity at the bottom of the cabin is 1.0-1.5 times the fluidization velocity of the biological packing.

[0015] Furthermore, the porous separator is a grid, a grille, or a perforated plate, and the aperture of the grid, grille, or perforated plate is smaller than the outer diameter of the outer spherical shell.

[0016] Furthermore, multiple auxiliary buoys are arranged in the circumferential direction of the cabin; multiple buoyancy chambers are arranged on both the guide tube and the water-lifting aeration unit.

[0017] The beneficial effects of this invention are as follows: The water-lifting aeration coupled with inorganic electron donor enhanced biological water quality improvement device of this invention includes an anchoring unit, a water-lifting aeration unit, a guide tube, and a bioreactor unit; the anchoring unit is fixed to the bottom of the water to provide basic support, and the floating part at the upper end of the first steel chain always floats on the water surface, using the first steel chain as a vertical reference axis to ensure that the water-lifting aeration unit, the guide tube, and the bioreactor unit are always coaxially aligned; the water-lifting aeration unit intermittently releases high-pressure gas bullets to generate an upward gas-liquid mixed flow, which flows vertically after being constrained by the guide tube, and the hydraulic slowing is achieved through the preset distance between the bioreactor and the guide tube. The flow rate is precisely controlled to ensure that the biological packing material is fully fluidized without being damaged by the impact. The bioreactor is connected to the first steel chain through a flexible connector, which further offsets the vibration caused by water flow fluctuations and airflow impacts. This solves the problem of the biological packing material being broken by high-speed airflow impacts due to the direct rigid connection between the bioreactor and the guide tube in the prior art. At the same time, the coaxial reference design avoids water flow deviation and ensures the uniform delivery of dissolved oxygen, pollutants and indigenous microorganisms. This allows the oxygenation and mixing and vertical circulation functions of the pumping aeration to work efficiently with the purification function of the bioreactor, achieving in-situ continuous improvement of reservoir water quality.

[0018] Furthermore, the inner spherical shell is fixed to the center of the outer spherical shell by evenly distributed supports. Regardless of how the biological packing material tumbles and collides with the water flow, the inner spherical shell always remains in the core position of the outer spherical shell, preventing eccentric displacement. Both the inner and outer spherical shells employ a porous mesh structure, allowing free penetration and exchange of water flow, dissolved oxygen, and pollutant molecules. The diameter ratio of the inner to outer spherical shells is controlled at 1:1.5-1:2.5, scientifically allocating the filling space for inorganic electron donors and the attachment space for soft biological carriers. A natural micro-oxygen environment is formed at the location of the inner spherical shell, enabling the inorganic electron donors to slowly and continuously oxidize and release electrons, providing a stable electron source for external aerobic denitrifying bacteria. This eliminates the need for additional organic carbon sources such as methanol and sodium acetate, avoiding secondary pollution and increased operating costs. This design ensures the overall structural stability of the biological packing material, avoiding problems such as uneven release of inorganic electron donors and insufficient local microbial activity caused by eccentric inner spherical shells, thus extending the service life of the biological packing material. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram of the structure of the water pumping aeration coupled with inorganic electron donor to enhance biological water quality improvement device provided in an embodiment of the present invention; Figure 2 This is a top view of the chamber in the water pumping aeration coupled with inorganic electron donor to enhance biological water quality improvement device provided in an embodiment of the present invention; Figure 3 This is a cross-sectional view of the biological packing material in the water pumping aeration coupled with inorganic electron donor enhanced biological water quality improvement device provided in an embodiment of the present invention.

[0021] In the diagram: 1. Bioreactor unit; 101. Chamber; 102. Central cylinder; 103. Packing chamber; 104. Supporting ribs; 2. Biological packing; 201. Inner spherical shell; 202. Outer spherical shell; 203. Inorganic electron donor; 204. Soft biological carrier; 205. Support rod; 3. Flow guide tube; 4. Water pumping aeration unit; 5. Counterweight; 6. First steel chain; 71. Hollow float; 72. Auxiliary float; 8. Second steel chain. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The serial numbers assigned to components in this document, such as "first," "second," etc., are merely used to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., 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 the invention and for 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 the invention.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] like Figure 1 to Figure 3 As shown in the figure, the water pumping and aeration coupled inorganic electron donor enhanced biological water quality improvement device provided in this embodiment of the invention includes an anchoring unit, a water pumping and aeration unit 4, a guide tube 3, and a bioreactor unit 1.

[0026] The anchoring unit uses precast C30 concrete counterweight blocks 5, each weighing 5-8 tons, with embedded steel connectors. It is fixed to a solid sediment layer or bedrock surface at the bottom of the reservoir to provide stable anchoring force for the entire device and prevent displacement due to water flow impact. A first steel chain 6 is fixedly installed on the counterweight block. The first steel chain 6 is a hot-dip galvanized lifting steel chain, with its lower end vertically bolted to a pre-embedded part at the top center of the counterweight block 5. A floating component is connected to the upper end. Initially, the length of the first steel chain 6 is determined according to the water depth. When the floating component floats on the water surface, the first steel chain 6 is under tension. The floating component is a hollow buoy 71 made of high-density polyethylene. The hollow buoy 71 always floats on the water surface. Initially, the first steel chain 6 is in a vertical position, providing a reference axis for the coaxial arrangement of each unit.

[0027] The water-lifting aeration unit 4 is an intermittent air-bomb water-lifting aerator. Its lower end is connected to the counterweight 5 via multiple second steel chains 8 evenly distributed along the circumference. The water-lifting aeration unit 4 is coaxially sleeved on the outside of the first steel chain 6, with a radial gap reserved between them to avoid friction between the first steel chain 6 and the water-lifting aeration unit 4 during operation. The water-lifting aeration unit 4 is supplied with air through an onshore air compressor and an air pipeline, intermittently releasing high-pressure air bombs to form an upward air-liquid mixture flow underwater, achieving vertical mixing of the water and oxygenation of the bottom layer.

[0028] The guide tube 3 is a cylindrical tube open at both ends, made of 304 stainless steel. The bottom end of the guide tube 3 is connected to the top of the water pumping aeration unit 4 by a flange and a coaxial bolt. The guide tube 3 is used to constrain the rising gas-liquid mixture to flow vertically and prevent radial diffusion.

[0029] The bioreactor unit 1 is a cylindrical chamber 101 made of 304 stainless steel. The interior of the chamber 101 is used to accommodate the biological packing material 2 and provide a space for water purification reaction. The top and bottom of the chamber 101 are respectively tied to the first steel chain 6 through flexible connectors to achieve a separate coaxial flexible connection with the guide tube 3. The chamber 101 is located directly above the guide tube 3 and the two are coaxially spaced. The spacing is determined by computational fluid dynamics (CFD) simulation to ensure that when the reservoir water level fluctuates, the biological packing material 2 in the chamber 101 is in a fully fluidized state and is not damaged by the impact of the high-speed rising gas-liquid mixture.

[0030] The water-lifting aeration coupled with inorganic electron donor-enhanced biological water quality improvement device of the present invention uses a counterweight 5 as the anchoring unit, which is fixed to the bottom of the water to provide basic support. The floating component at the upper end of the first steel chain 6 always floats on the water surface. The first steel chain 6 serves as the vertical reference axis, ensuring that the water-lifting aeration unit 4, the guide tube 3, and the bioreactor unit 1 are always coaxially aligned. The water-lifting aeration unit 4 intermittently releases high-pressure gas to generate an upward gas-liquid mixture flow, which flows vertically after being constrained by the guide tube 3. The preset distance between the bioreactor and the guide tube 3 completes the hydraulic buffering, allowing the flow velocity to be precisely controlled to the biological level. The biological packing material 2 is fully fluidized and not damaged by impact; the bioreactor is connected to the first steel chain 6 through a flexible connector, which further offsets the vibration of water flow fluctuations and airflow impacts. This solves the problem of the biological packing material 2 being broken by high-speed airflow impacts due to the direct rigid connection between the bioreactor and the guide tube 3 in the prior art. At the same time, the coaxial reference design avoids water flow deviation and ensures the uniform delivery of dissolved oxygen, pollutants and indigenous microorganisms. This enables the oxygenation and mixing and vertical circulation functions of the pumping aeration and the purification function of the bioreactor to work together efficiently, achieving in-situ continuous improvement of reservoir water quality.

[0031] In one embodiment, the biological packing material 2 has a double-layer spherical structure, comprising an inner spherical shell 201 and an outer spherical shell 202. Both the inner and outer spherical shells 201 and 202 are made of ABS engineering plastic injection molded into a porous mesh structure, allowing free exchange of water flow and dissolved substances. The outer wall of the inner spherical shell 201 is fixed to the center of the outer spherical shell 202 by a support member. In this embodiment, the support member is a plurality of support rods 205. One end of the support rod 205 is heat-fused and fixed to the outer surface of the inner spherical shell 201, and the other end of the support rod 205 is heat-fused and fixed to the inner wall of the outer spherical shell 202, so that the inner spherical shell 201 is always precisely positioned at the center of the outer spherical shell 202. The diameter ratio of the inner spherical shell 201 to the outer spherical shell 202 is 1:1.5-1:2.5. In this embodiment, the diameter ratio of the inner spherical shell 201 to the outer spherical shell 202 is 1:1.875. The inner spherical shell 201 has a diameter of 80 mm, and the outer spherical shell 202 has a diameter of 150 mm. This ratio balances the electron donor loading amount and the biological carrier attachment area.

[0032] In one embodiment, the sealed cavity formed inside the inner spherical shell 201 is filled with granular inorganic electron donors 203, which provide continuous electrons for microbial metabolism; the annular cavity formed between the inner spherical shell 201 and the outer spherical shell 202 is filled with a soft biological carrier 204, which provides attachment and growth sites for microorganisms; after the device has been running for a period of time, the soft biological carrier 204 naturally attaches to indigenous aerobic denitrifying bacteria, heterotrophic bacteria, polyphosphate-accumulating bacteria and other functional microorganisms in the reservoir water, without the need for artificial inoculation.

[0033] In one embodiment, since the soft biological carrier 204 inside the outer shell 202 and the flowing water consume most of the dissolved oxygen, and since the inner shell 201 is located inside the outer shell 202, a stable micro-oxygen environment is formed inside the inner shell 201. The inorganic electron donor 203 is located in this micro-oxygen environment, and its oxidation reaction rate is precisely controlled, enabling it to continuously and slowly release electrons, providing a stable long-term supply of electrons for the aerobic denitrifying bacteria attached to the outer shell.

[0034] In one embodiment, the inorganic electron donor 203 includes at least one low-valence inorganic metal element or compound that can provide electrons, such as sponge iron or pyrite, which has no adverse effect on water quality. This embodiment preferably uses sponge iron particles formed by pressing reduced iron powder. The oxidation reaction of sponge iron particles is mild under micro-oxygen conditions, with a stable electron release rate, and the oxidation products can form precipitates with phosphorus, simultaneously achieving phosphorus removal.

[0035] In one embodiment, the soft biocarrier 204 is at least one of polyurethane sponge, polyvinyl alcohol sponge, polypropylene fiber, etc. In this embodiment, polyurethane sponge block is preferred. Polyurethane sponge block has good hydrophilicity and biocompatibility, and can quickly enrich indigenous microorganisms to form a stable biofilm.

[0036] In one embodiment, the chamber 101 extends through both its upper and lower ends, and both ends are bolted to perforated partitions. A central cylinder 102, made of 304 stainless steel, is coaxially welded inside the chamber 101. The central cylinder 102 has upper and lower perforated partitions extending through its upper and lower ends, respectively. A first steel chain 6 passes through the interior of the central cylinder 102, with a radial gap between the central cylinder 102 and the first steel chain 6 to prevent friction between them during operation. Multiple support ribs 104 are welded between the inner wall of the chamber 101 and the outer wall of the central cylinder 102. These support ribs 104 are evenly and symmetrically distributed around the circumference of the chamber 101, dividing the annular space inside the chamber 101 into multiple packing chambers 103. In the radial direction of the chamber 101, one end of each support rib 104 is fully welded to the outer wall of the central cylinder 102, and the other end is fully welded to the inner wall of the chamber 101. The top end of the support rib 104 is fixedly connected to the lower surface of the upper porous separator, and the bottom end of the support rib 104 is fixedly connected to the upper surface of the lower porous separator.

[0037] In one embodiment, the distance between the chamber 101 and the guide tube 3 is determined by CFD simulation calculation based on the fact that the maximum flow velocity at the bottom of the chamber 101 is 1.0-1.5 times the fluidization velocity of the biological packing 2.

[0038] Specifically, considering the characteristics of the rising gas-liquid mixture generated by reservoir water pumping aeration, computational fluid dynamics was used to accurately simulate the flow field between the guide tube 3 and the chamber 101, providing a quantitative basis for the spacing design. The simulation process strictly followed the basic conservation laws of fluid mechanics, and a suitable turbulence model was selected based on the operating conditions of this embodiment, as follows: In this embodiment, the flow condition is an upward gas-liquid mixture flow under normal temperature and pressure. The reservoir water temperature is stable at 5-25℃. The liquid phase (water) can be regarded as an incompressible fluid. The entire flow process is approximately isothermal. There is no need to solve the energy equation. Only the mass conservation equation and momentum conservation equation need to be solved. A turbulence model is used to close the equation set to solve the turbulence fluctuation term.

[0039] The law of conservation of mass states that the mass of fluid flowing into a control volume per unit time is equal to the mass of fluid flowing out of the control volume per unit time interval. For incompressible fluids, their density ρ is constant, therefore the equation can be simplified to: ,in, Let be a velocity vector, and let its components in the x, y, and z directions of the three-dimensional Cartesian coordinate system be u, v, and w, respectively.

[0040] The momentum conservation equation is based on Newton's second law, stating that the rate of change of momentum of a fluid element is equal to the sum of all forces acting on it. For incompressible fluids, the vector form of the momentum conservation equation is: In the formula: p For static pressure, for Stress tensor, and and These represent gravitational volume forces and external volume forces, respectively. The stress tensor... For Newtonian fluids: In the formula: m For fluid dynamic viscosity; I This is a unit tensor. In practical numerical calculations, for ease of solution, the above vector equations are expanded into a system of scalar equations in a three-dimensional Cartesian coordinate system (x, y, z): x-direction: y direction: z-direction: FLUENT software provides mixed length models and standards. k-e Model, RNG k-e Model, Realizable k-e Models, standards k-oh Model, SST k-oh Dozens of turbulence models are available, including the Reynolds stress model (RSM) and the large eddy model (LES). A standard model is selected here. k-e Model, RNG k-e This section introduces two commonly used models in hydrodynamic simulation. (Standard) k-e The model is based on turbulent kinetic energy ( k The model of the transmission equation and its dissipation rate (ε). k The model's transport equations are derived from the exact equations, while e The model's transfer equations are obtained through physical reasoning.

[0041] Turbulent kinetic energy k The equation is: Dissipation rate e The equation is: In the formula: G k This represents the turbulent kinetic energy generation term due to the average velocity gradient; G b It is the turbulent kinetic energy generation term caused by buoyancy; Y M This represents the contribution of fluctuating expansion to the total dissipation rate in compressible turbulence. S k and User-defined source items; , , All are empirical constants; and They are respectively k and e Turbulent Prandtl numbers, with default values ​​of respectively , , .

[0042] Turbulent viscosity ,Depend on k and e The combined formula yields: In the formula: It is a constant, with a default value of 0.09.

[0043] Based on RNG k-e The turbulence model is derived from the transient Navier-Stokes equations using a mathematical technique called the "renormalization group" (RNG). This analytical derivation process produces a constant that differs from the standard equations. k-e The model is a model of the model, and additional terms and functions are introduced into the transport equations for k and ε.

[0044] Turbulent kinetic energy k The equation is: Dissipation rate e The equation is: In the formula: and They are k and e The reciprocal of the effective Prandtl number, other parameters are the same as the standard. k-e The model is the same.

[0045] For high Reynolds numbers, the formula for calculating turbulent viscosity is: In the formula: It's the eddy current velocity, in RNGk -e The constant value in the model is 0.0845; This is the turbulent kinetic energy generation term generated by the average velocity gradient; This refers to the turbulent kinetic energy generation term caused by buoyancy. This represents the contribution of fluctuating expansion in compressible turbulent flow to the total dissipation rate (in this embodiment, the flow is incompressible, so this term is 0); R is an additional dissipation term unique to the RNG model, used to correct the dissipation rate under high strain rate flow.

[0046] A three-dimensional cylindrical computational domain was constructed with the central axis of the guide tube 3 as the axis of symmetry. The axial range extends from 1.0m below the outlet of the guide tube 3 to 30.0m above the bottom of the hull 101, and the radial range is 10 times the outer diameter of the guide tube 3 (to avoid boundary effects affecting the accuracy of the flow field calculation). A structured hexahedral mesh was used for discretization, and the mesh was refined in the regions of the outlet of the guide tube 3 and the bottom of the hull 101. The optimal mesh size was determined to be 1.2 million through mesh independence verification.

[0047] The outlet of the guide tube 3 is set as a velocity inlet, and the maximum velocity of the rising gas-liquid mixture is given as 5.0 m / s (corresponding to the rated operating condition of the pumping aerator); the top of the computational domain is set as a pressure outlet, and the pressure is standard atmospheric pressure; the wall of the guide tube 3 and the side wall of the computational domain are set as non-slip wall conditions.

[0048] The governing equations were discretized using the finite volume method. The pressure-velocity coupling was performed using the SIMPLE algorithm. The convection term was represented by a second-order upwind scheme, and the diffusion term by a central difference scheme. Numerical calculations were performed on the flow field at five different spacings (5.0 m, 10.0 m, 15.0 m, 20.0 m, and 25.0 m), and the maximum upward velocities at the bottom of compartment 101 were found to be 4.12 m / s, 3.01 m / s, 2.27 m / s, 1.66 m / s, and 1.18 m / s, respectively.

[0049] Based on the critical fluidization velocity of 1.25 m / s for the biological packing, 20.0 m was determined as the optimal spacing: at this point, the maximum upward flow velocity at the bottom of chamber 101 is 1.66 m / s, which satisfies the requirement for complete fluidization of the biological packing balls (flow velocity ≥ critical fluidization velocity) and avoids the impact damage of high-speed water flow on the packing (flow velocity ≤ 1.5 times critical fluidization velocity).

[0050] In one embodiment, the porous separator is a grid, grille, or perforated plate. The grid, grille, or perforated plate is made of 304 stainless steel. The aperture of the grid, grille, or perforated plate is smaller than the outer diameter of the outer spherical shell 202. The grid, grille, or perforated plate can effectively block the biological filler 2 from flowing out from both ends of the chamber 101, while allowing water flow, dissolved oxygen, and pollutant molecules to pass freely, thus preventing the chamber 101 from becoming clogged.

[0051] In one embodiment, multiple auxiliary floats 72 are evenly arranged circumferentially on the outer wall of the chamber 101. These auxiliary floats 72 are used to balance the weight of the chamber 101. Multiple buoyancy chambers are evenly distributed circumferentially on the outer walls of the guide tube 3 and the water-lifting aeration unit 4. These buoyancy chambers maintain the vertical orientation of the guide tube 3 and the water-lifting aeration unit 4 and ensure coaxiality with the first steel chain 6, preventing water flow deviation from affecting the treatment effect. Furthermore, by providing multiple auxiliary floats 72 on the outer wall of the chamber 101 and multiple buoyancy chambers on the outer walls of the guide tube 3 and the water-lifting aeration unit 4, in the initial state, the guide tube 3 and the water-lifting aeration unit 4 can be stably positioned close to the bottom and remain coaxial with the first steel chain 6. When the water depth changes, the auxiliary floats 72 on the chamber 101 can maintain the tension of the first steel chain 6 below the chamber 101, thereby preventing changes in the distance between the chamber 101 and the guide tube 3 due to changes in water depth.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for enhancing biological water quality improvement by coupling water pumping aeration with an inorganic electron donor, characterized in that, include: An anchoring unit is fixed to the bottom of the water; a first steel chain is installed on the anchoring unit, and a floating component is installed at the upper end of the first steel chain, which always floats on the water surface. The water-lifting aeration unit is connected to the anchoring unit via a second steel chain, and the water-lifting aeration unit is coaxially sleeved on the outside of the first steel chain. The water-lifting aeration unit is used to generate an upward gas-liquid mixture flow underwater. The guide tube is fixedly installed above the water pumping aeration unit. The guide tube is used to guide the rising gas-liquid mixture to flow in the vertical direction. The bioreactor unit is a cylindrical chamber that houses the biological packing material and provides a water purification reaction space. The chamber is connected to the first steel chain via a flexible connector. The chamber and the top of the guide tube are coaxially spaced apart. The distance between the chamber and the guide tube is determined by computational fluid dynamics simulation to ensure that the biological packing material is in a fully fluidized state and is not damaged by the high-speed rising gas-liquid mixture. The biological packing material has a double-layered spherical structure, consisting of an inner spherical shell and an outer spherical shell. Both the inner and outer spherical shells are porous mesh structures. The inner spherical shell is fixed to the center of the outer spherical shell by a support. The diameter ratio of the inner spherical shell to the outer spherical shell is 1:1.5-1:2.

5. The inner spherical shell is filled with granular inorganic electron donors, which provide electrons for microbial metabolism; a soft biological carrier is filled between the inner and outer spherical shells, which provides attachment and growth sites for microorganisms; and aquatic native functional microorganisms are attached to the soft biological carrier. The inorganic electron donor is located in a micro-oxygen environment formed inside the inner spherical shell. The micro-oxygen environment is used to control the slow release rate of the inorganic electron donor, which can continuously and slowly release electrons to provide the electron donors needed for the metabolism of aerobic denitrifying bacteria. The cabin extends through both its upper and lower ends, each equipped with a perforated partition. A central cylinder is coaxially fixed inside the cabin, passing through the perforated partition, and a first steel chain passes through the central cylinder. Multiple support ribs are arranged between the inner wall of the cabin and the outer wall of the central cylinder, evenly distributed around the circumference of the cabin, dividing the interior of the cabin into multiple packing compartments. In the radial direction of the cabin, one end of the support rib is fully welded to the outer wall of the central cylinder, and the other end is fully welded to the inner wall of the cabin. The top of the support rib is fixedly connected to the lower surface of the upper perforated partition, and the bottom of the support rib is fixedly connected to the upper surface of the lower perforated partition. The distance between the chamber and the guide tube is determined based on the fact that the maximum flow velocity at the bottom of the chamber is 1.0-1.5 times the fluidization velocity of the biological packing.

2. The water pumping aeration coupled with inorganic electron donor to enhance biological water quality improvement device according to claim 1, characterized in that: Inorganic electron donors include at least one of sponge iron and pyrite, which have no adverse effects on water quality.

3. The water pumping aeration coupled with inorganic electron donor to enhance biological water quality improvement device according to claim 1, characterized in that: The soft biological carrier is at least one of polyurethane foam, polyvinyl alcohol foam, and polypropylene fiber.

4. The water pumping aeration coupled with inorganic electron donor to enhance biological water quality improvement device according to claim 1, characterized in that: The porous separator is a grid, grille, or perforated plate, and the aperture of the grid, grille, or perforated plate is smaller than the outer diameter of the outer spherical shell.

5. The water pumping aeration coupled with inorganic electron donor to enhance biological water quality improvement device according to claim 1, characterized in that: Multiple auxiliary buoys are installed in the circumference of the hull; multiple buoyancy chambers are installed on both the guide tube and the water-lifting aeration unit.

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