Ozone micro air floatation equipment and combined system overflow pollution treatment method

Abstract

The invention provides ozone micro-fine air flotation equipment and a combined system overflow pollution treatment method, and relates to the field of sewage treatment.The main body equipment comprises a water pump, an ozone generator, an ozone booster pump, a dissolved air pipe type micro-bubble generator, a vertical shallow air cyclone flotation tank and an ozone tail gas destructor; the dissolved gas pipe type micro-bubble generator comprises a dissolved gas pipe, a conical-hopper-shaped hollow inner cylinder fixed in the dissolved gas pipe and a dissolved gas releaser, and the ozone generator is communicated with a gas phase inlet of the dissolved gas pipe through an ozone booster pump; an outer ring cavity is formed between the conical-hopper-shaped hollow inner cylinder and the inner wall of the gas dissolving pipe, a gas dissolving water outlet is formed in the bottom of the gas dissolving pipe, and the gas dissolving water outlet is communicated with the vertical shallow cyclone floating tank through a gas dissolving releaser. The vertical shallow-layer cyclone floating tank is composed of a tangential water inlet, a hollow inner cylinder, a shallow-layer inclined plate, a sludge discharge port, a water discharge port, an exhaust port and a slag discharge port. The device can improve the ozone dissolved gas mass transfer efficiency, realizes rapid and efficient sewage treatment, and has the advantages of convenience in operation and small occupied area.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to an ozone micro-flotation device and a combined overflow pollution treatment method. Background Technology

[0002] Combined sewer overflows (CSOs) pollution refers to the situation in combined sewer systems where the combined flow of rainwater, domestic sewage, and industrial wastewater exceeds the system's capacity due to rainfall or snowmelt. This results in untreated wastewater being directly discharged into receiving water bodies through overflow outlets, depleting dissolved oxygen and impacting aquatic flora and fauna and the overall aquatic ecosystem. Urban combined sewer overflow pollution is characterized by its initial effects, discontinuity, and temporal nature. It is characterized by high suspended solids (SS) content and severe pollution loads, with SS levels reaching 300–500 mg / L and COD levels reaching 200–400 mg / L, making control of CSOs pollution extremely difficult. In recent years, rapid urban expansion and continuous urban renewal, along with frequent sudden rainstorm events, have led to large and frequent CSO flows, severely restricting the control of urban non-point source pollution. Therefore, the control of urban combined sewer overflow pollution has received significant attention both domestically and internationally.

[0003] Pollution control measures for combined sewer overflows in urban areas mainly include source reduction, pipeline interception, storage and regulation, and end-of-pipe control. One of the current key tasks is the effective implementation of end-of-pipe control. Conventional treatment equipment commonly used in end-of-pipe control, such as hydrocyclones, coagulation sedimentation tanks, high-efficiency sedimentation tanks, and coagulation flotation, while capable of handling the large volume and discontinuous nature of combined sewer overflows, have limited effectiveness in removing key indicators such as chemical oxygen demand (COD) and biochemical oxygen demand (BOD). For example, chemically enhanced primary treatment based on "magnetic flocculation" is often used to control overflow pollution due to its short retention time and small footprint, but it is difficult to achieve faster and more efficient pollution load removal with lower flocculant dosages and treatment costs.

[0004] Ozone is widely used in water treatment, possessing advantages such as high oxidation efficiency, strong stability, ease of on-site production, and no secondary pollution. It is an effective technical means to decompose organic pollutants and reduce COD levels in water bodies. Air flotation (AF) is characterized by its ability to efficiently separate suspended solids in water, simple operation, and low operating costs. Traditional ozone oxidation-coagulation-sedimentation (or AF) combined processes include a series of chemical and physicochemical units, such as oxidation, coagulation, sedimentation, or AF, as well as other auxiliary devices to enhance separation efficiency. Individual treatment technologies have a certain selectivity in pollutant removal, leading to problems such as long treatment processes, high energy consumption, and poor process adaptability. The multi-element coupled ozone AF integrated technology synergistically utilizes the characteristics of ozone oxidation and AF separation, simultaneously completing multiple processes such as demulsification or flocculation, solid-liquid separation, color / odor / taste removal, and disinfection within a single operating unit. Compared to traditional combined processes, it can significantly reduce the footprint and energy consumption. In addition, ozone flotation integrated technology, with its characteristics of being fast, efficient and strong resistance to shock loads, is a very applicable and increasingly widely used technical solution for the treatment of urban combined sewer overflow pollution that requires rapid response in the face of sudden, high pollution loads.

[0005] The commonly used integrated ozone flotation process uses ozone instead of air as the dissolved gas source. Ozone is injected into the dissolved gas system and released inside the separator to generate uniform ozone microbubbles. This simultaneously achieves contact adhesion between the ozone bubbles and pollutants, as well as the oxidation of the pollutants, ultimately completing the flotation separation. The entire contact mixing and flotation separation process takes place in a non-pressurized, closed device. A slag discharge port is located at the top of the device, and the automatic control system performs timed slag discharge operations, utilizing timed rises and falls of the water level for fully automated slag discharge. However, during operational intervals and when the water flow is disturbed, slag settles at the bottom of the tank and is carried by the water flow to the outlet, reducing the removal efficiency of organic matter and suspended solids in the effluent and affecting the normal operation of the ozone flotation device. Furthermore, limited by traditional dissolved gas release foaming technology, the generated ozone bubbles not only have a large particle size, but the ozone molecules also have low solubility in water. This causes suspended matter to "annihilate" ozone molecules during the ozone flotation process, resulting in low ozone utilization and interference with flocculation effects.

[0006] To reduce the impact of scum on the removal efficiency of organic matter and suspended solids in effluent, Professor Jin Pengkang et al. from Xi'an University of Architecture and Technology proposed a composite ozone flotation integrated device in ZL201710573796.3 for urban wastewater reuse. This vertical device achieves zoned ozone oxidation, flotation separation, and automatic scum discharge through a three-layer structure (cylinder, intermediate cylinder, and central cylinder), offering advantages such as high treatment efficiency, automatic scum and sludge discharge, convenient installation, and simple operation. However, the suspended solids concentration in combined sewer overflows in urban areas can reach 300-500 mg / L, making aeration discs prone to clogging by suspended particles, leading to cumbersome operation and maintenance. Furthermore, the complex internal structure increases maintenance difficulty and cost.

[0007] Jin Li et al. from the Shandong Provincial Institute of Water Resources Science disclosed a low-energy-consumption membrane ozone flotation integrated device in Chinese patent ZL202210513661.9. The main components include an ozone generator, a dissolving tank, an inlet pump, microporous aeration heads, an ozone reaction tank, and a residual gas collection pipe. This process integrates ozone dissolved air flotation and ozone oxidation processes. By creating a vortex flow between the ozone-treated dissolved air water and the raw water after adding coagulant within the inner cylinder, the ozone and dissolved air water are completely mixed. By micronizing the ozone, its specific surface area is increased, oxidizing organic matter in the water during flotation and reducing the turbidity and color of the raw water. This technology features high ozone utilization, low energy consumption, and low emissions. However, this technology uses traditional microporous aeration, and there is still significant room for improvement in ozone utilization, gas-liquid contact mass transfer, and equipment compactness.

[0008] To address the challenges of complex and variable water quality and volume in combined sewer overflow systems, leading to poor adaptability to various operating conditions, Tang Dingding et al. from China Construction Third Engineering Bureau Green Industry Investment Co., Ltd. disclosed a method for preparing an ozone flotation-flocculation agent for combined sewer overflow wastewater in Chinese Patent ZL202310100015.4. This method involves mechanically ball-milling activated carbon, aluminum powder, and an aluminum-based flocculant to obtain a composite agent. The activated carbon and aluminum create an alkaline environment to promote the activation and precipitation of zero-valent aluminum. Suspended solids are removed through flocculation and flotation by dissolving the aluminum and the aluminum-based flocculant. Simultaneously, activated carbon activates ozone, improving ozone utilization. This solution is characterized by high efficiency, stability, and environmental friendliness. However, long-term operation of the ozone flotation process with chemical dosing and flocculation suffers from high economic costs, low treatment rates, and poor adaptability to various operating conditions due to the maintenance of specific process conditions and continuous input of key materials, making large-scale application difficult.

[0009] Later, Tang Dingding et al. disclosed an ozone flotation treatment process for combined sewer overflow in Chinese patent ZL202310104566.8, which mainly consists of a reaction zone, a contact zone, a separation zone, and a catalytic zone. This process integrates coagulation, dissolved air flotation, and ozone catalytic oxidation technologies to achieve efficient treatment of combined sewer overflow, effectively reducing the concentration of suspended solids and COD in the water. It has advantages such as good treatment effect, strong resistance to shock loads, and easy mobility and dispatch. However, the dissolved air equipment in this process requires a dissolved air pressure of 0.3-0.4 MPa, and it also requires the addition of reagents for coagulation. The catalytic oxidation performance decays relatively quickly, resulting in problems such as high overall operation and maintenance costs and long retention time.

[0010] In summary, although ozone flotation technology has shown promising initial results in the treatment of combined sewer overflows (CSOs) in urban areas, its ozone dissolution rate is low due to limitations in existing microbubble generation technology, resulting in some waste of ozone generated by the ozone generator. Based on the concept of enhanced mass transfer through micro-interface contact, miniaturizing the ozone bubbles would undoubtedly improve ozone mass transfer efficiency, thereby increasing ozone utilization. On the other hand, conventional horizontal flow ozone flotation suffers from drawbacks such as large footprint, low separation zone volume utilization, and low gas-liquid mixing efficiency; existing vertical flow ozone flotation devices exhibit weak resistance to shock loads and poor treatment stability.

[0011] In view of this, addressing the characteristics and challenges of urban combined sewer overflows and existing ozone flotation processes, and resolving the issues of high operating costs, low treatment efficiency, and lack of high-throughput micro-foaming technology for ozone flotation, is of great practical significance. Summary of the Invention

[0012] The purpose of this invention is to provide an ozone micro-flotation device and a combined sewer overflow pollution treatment method to solve the technical problems of existing sewage treatment flotation devices, which are unable to generate high-flux microbubbles and have low treatment efficiency. The various technical effects of the preferred solutions among the many technical solutions provided by this invention are detailed below.

[0013] To achieve the above objectives, the present invention provides the following technical solution: The ozone micro-air flotation device provided by this invention includes an ozone generator, an ozone booster pump, and a water pump, a dissolved air tube microbubble generator, and a vertical shallow cyclone flotation tank connected sequentially along the water flow direction, wherein: The dissolved gas tube microbubble generator includes a dissolved gas tube and a cone-shaped hollow inner cylinder fixed inside the dissolved gas tube. The ozone generator is connected to the gas phase inlet of the dissolved gas tube through the ozone booster pump. An outer annular cavity is provided between the conical hollow inner cylinder and the inner wall of the dissolved gas tube. A flow port is opened at the bottom of the conical hollow inner cylinder, and the flow port is connected to the outer annular cavity. Part of the fluid injected into the dissolved gas tube can circulate around the conical hollow inner cylinder, the flow port and the outer annular cavity. The bottom of the dissolved gas pipe is provided with a dissolved gas water outlet, which is connected to the vertical shallow cyclone flotation tank through a dissolved gas release device.

[0014] Preferably, the dissolved air pipe includes a straight pipe section, and the conical hollow inner cylinder includes an inner cylinder body and a baffle, wherein: The inner cylinder and the baffle are both fixed inside the straight pipe section. The baffle is located below the bottom of the inner cylinder, and the flow port is formed between the inner cylinder and the baffle.

[0015] Preferably, the baffle has an arc-shaped structure, and the concave side of the baffle faces the inner cylinder.

[0016] Preferably, the dissolved gas tube further includes a Venturi tube gas-liquid pre-dispersion section, which is connected to the upper end of the straight pipe section. The top of the Venturi tube gas-liquid pre-dispersion section is the liquid phase inlet, and the middle part of the Venturi tube gas-liquid pre-dispersion section is the throat. The throat is connected to a gas injection pipe, and the gas injection pipe is provided with a gas phase inlet.

[0017] Preferably, the vertical shallow cyclone flotation tank includes a vertical tank body, a tangential inlet pipe, a cyclone flotation tank inner cylinder located within the vertical tank body, and an inclined plate assembly, wherein: The bottom of the vertical tank is provided with a drain outlet, the upper part of the vertical tank is provided with an exhaust outlet and a slag discharge outlet, the exhaust outlet is connected to an ozone tail gas destroyer, and the bottom of the inner cylinder of the cyclone flotation tank is connected to a sludge discharge outlet. The tangential water inlet pipe is horizontally arranged and connected to the inner cylinder of the cyclone flotation tank. The tangential water inlet pipe has a tangential cyclone water inlet, which is connected to the dissolved gas release device. The inclined plate assembly is located above the inner cylinder of the cyclone flotation tank and is used to coalesce tiny oil droplets and suspended impurities.

[0018] Preferably, the number of inclined plate assemblies is at least two sets, and each set of inclined plate assemblies is arranged at intervals around the axis of the vertical tank.

[0019] Preferably, the inclined plate assembly includes concentric frustum inclined plates. In each group of concentric frustum inclined plates, the concentric frustum inclined plates are arranged at intervals along the vertical direction. The spacing between adjacent concentric frustum inclined plates is equal or unequal, and there is a channel for fluid flow between adjacent concentric frustum inclined plates.

[0020] Preferably, the inner cylinder of the cyclone flotation tank has an open top, and the axis of the open top is collinear with the axis of the vertical tank body.

[0021] Preferably, the concentric frustum inclined plate is inclined downward along the axis away from the vertical tank body.

[0022] This invention also provides a method for treating combined sewer overflow pollution, using the ozone micro-flotation device according to any one of claims 1-9, wherein the vertical shallow cyclone flotation tank includes a hollow inner cylinder cyclone separation zone and an upper frustum-shaped inclined plate shallow sedimentation separation zone, the method comprising: S1. After the wastewater is pressurized by the water pump, it enters the liquid phase inlet of the dissolved air tube microbubble generator. The ozone generated by the ozone generator is sent into the dissolved air tube through the ozone booster pump, and initial bubbles are generated under the action of hydraulic shear. Subsequently, the bubble flow circulates around the cone-shaped hollow inner cylinder, the flow port and the outer ring cavity under the inertial boost. S2. The dissolved air water generated through the dissolved air pipe is depressurized and released by the dissolved air releaser to generate ozone microbubbles. Then, it is carried by the sewage into the vertical shallow cyclone flotation tank for liquid-solid centrifugal separation. The separated heavy component particles such as mud and sand are discharged from the bottom sludge discharge port. S3. Under the action of the rotating wake of the cyclone separation zone of the hollow inner cylinder, the ozone microbubbles accelerate and collide with and adhere to suspended solid particles and oil droplets, forming an adhesus with a density less than water that floats to the surface. At the same time, the tiny oil droplets and suspended impurities aggregate and increase in the shallow sedimentation separation zone of the upper truncated cone-shaped inclined plate. S4. Discharge the treated wastewater and scum from different outlets.

[0023] The ozone micro-flotation device and combined sewer overflow pollution treatment method provided by this invention have the following advantages compared with the prior art: the process flow is simple and reliable, the equipment has a high degree of integration, and it comprehensively considers the problems of rapid separation of fine solid particles, ozone mass transfer enhanced by microbubbles and oxidation decomposition of recalcitrant organic matter, thus achieving efficient removal of solid particles and organic pollutants from combined sewer overflow sewage in one stop. Part of the fluid injected into the dissolved gas tube can circulate around the conical hollow inner cylinder, the flow port, and the outer annular cavity. The dissolved gas tube microbubble generator, through the synergistic coupling of jet breaking and axial circulation, increases the specific surface area during the gas-liquid contact mass transfer process, increases the residence time of ozone, promotes the transmembrane dissolution and absorption mass transfer of ozone molecules during transport, and improves the ozone dissolved gas mass transfer efficiency. This breaks through the technical bottleneck of conventional tank-type dissolved gas equipment in short-time, low-pressure, and supersaturated dissolved gas. It can achieve a dissolved gas efficiency of over 90% when the dissolved gas pressure is less than 0.3MPa and the dissolved gas time is less than 3.5s. This method can achieve rapid and efficient treatment of combined overflow sewage, and has the advantages of convenient operation, small footprint, convenient scheduling, and strong applicability. It can provide convenience for equipment integration and skid mounting under different working conditions. Attached Figure Description

[0024] 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.

[0025] Figure 1 This is a schematic diagram of the structure of the ozone micro-air flotation device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a dissolved gas tube microbubble generator provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a vertical shallow cyclone flotation tank provided in an embodiment of the present invention.

[0026] In the diagram: 1. Sewage inlet pipe; 2. Water pump; 3. Ozone generator; 4. Ozone booster pump; 5. Dissolved gas tube microbubble generator; 51. Dissolved gas tube; 52. Dissolved gas release device; 511. Gas injection pipe; 512. Straight pipe section; 513. Dissolved gas water outlet; 514. Conical hollow inner cylinder; 5141. Inner cylinder body; 5142. Baffle; 515. Venturi tube gas-liquid pre-dispersion section; 516. Throat; 517. Outer annular cavity; 518. Flow port; 6. Vertical shallow cyclone flotation tank; 61. Tangential cyclone inlet; 62. Concentric cone inclined plate; 63. Exhaust port; 64. Slag discharge port; 65. Mud discharge port; 66. Drainage port; 67. Inner cylinder of cyclone flotation tank; 7. Ozone tail gas destroyer. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0028] In the description of this invention, it should be understood that the terms "center," "length," "width," "height," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and "side," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0029] This invention provides an ozone micro-flotation device and a combined sewer overflow pollution treatment method, which can achieve rapid and efficient treatment of combined sewer overflow sewage. It has the advantages of convenient operation, small footprint, convenient scheduling, and strong applicability, and can provide convenience for equipment integration and skid mounting under different working conditions.

[0030] The following is combined with Figures 1-3 The technical solution provided by this invention will be described in more detail below.

[0031] Example 1: like Figures 1-3 As shown, the ozone micro-flotation device provided by the present invention includes an ozone generator 3, an ozone booster pump 4, and a water pump 2, a dissolved air tube type microbubble generator 5, and a vertical shallow cyclone flotation tank 6 connected sequentially along the water flow direction. The dissolved air tube type microbubble generator 5 includes a dissolved air tube 51 and a conical hollow inner cylinder 514 fixed inside the dissolved air tube 51. The ozone generator 3 is connected to the gas phase inlet of the dissolved air tube 51 through the ozone booster pump 4. The conical hollow inner cylinder 514 is connected to the dissolved air tube 51 through the gas phase inlet of the dissolved air tube 51. An outer annular cavity 517 is provided between the inner walls of the tube 51, and a flow port 518 is provided at the bottom of the conical hollow inner cylinder 514. The flow port 518 is connected to the outer annular cavity 517. Part of the fluid injected into the dissolved air tube 51 can circulate around the cylinder wall of the conical hollow inner cylinder 514, the flow port 518 and the outer annular cavity 517. A dissolved air water outlet 513 is provided at the bottom of the dissolved air tube 51. The dissolved air water outlet 513 is connected to the vertical shallow cyclone flotation tank 6 through the dissolved air release device 52.

[0032] For details, see Figure 1 As shown, the dissolved air tube microbubble generator 5 is installed between the sewage inlet pipe 1 and the vertical shallow cyclone flotation tank 6. Its liquid phase inlet is connected to the overflow sewage inlet pipeline after being pressurized by the water pump 2. The inlet of the vertical shallow cyclone flotation tank 6 is connected to the outlet of the dissolved air tube microbubble generator 5, and the drain outlet 66 of the vertical shallow cyclone flotation tank 6 is connected to the effluent pipeline. The ozone tail gas destroyer 7 is connected to the exhaust port 63 at the top of the vertical shallow cyclone flotation tank 6.

[0033] Ozone generator 3 is connected to the gas injection pipe 511 of dissolved air tube microbubble generator 5 via ozone booster pump 4, providing the required gas source for the bubble formation process. The ozone injection rate of dissolved air tube microbubble generator 5 is 5%-10% of the inlet water flow rate, and the average bubble particle size is less than 50μm.

[0034] See Figure 1 and Figure 2 As shown, the inlet of the dissolved gas pipe 51 is connected to the sewage pipeline, the outlet of the dissolved gas pipe 51 is connected to the dissolved gas release device 52, the outlet of the dissolved gas release device 52 is connected to the inlet of the vertical shallow cyclone flotation tank 6, and the cone-shaped hollow inner cylinder 514 is a fixed dissolved gas internal structure. The axial circulation increases the gas residence time, thereby enhancing the ozone dissolved gas mass transfer.

[0035] The dissolved gas release device 52 can preferably be a ball valve, which adjusts the dissolved gas pressure by adjusting the valve opening. It has no risk of clogging and requires no regular maintenance. The ozone injection volume is 5%-10% of the inlet water flow rate, and the average particle size of the bubbles is less than 50μm.

[0036] As an alternative implementation, see [link to implementation details]. Figure 1 and Figure 2 As shown, the dissolved gas pipe 51 includes a straight pipe section 512, see [reference]. Figure 2 As shown, Figure 2 The arrows indicate the direction of fluid flow. The conical hollow inner cylinder 514 includes an inner cylinder body 5141 and a baffle 5142, wherein: the inner cylinder body 5141 and the baffle 5142 are both fixed inside the straight pipe section 512, the baffle 5142 is located below the bottom of the inner cylinder body 5141, and the flow port 518 is formed between the inner cylinder body 5141 and the baffle 5142. For details, see [link to documentation]. Figure 2 As shown, the baffle 5142 has an arc-shaped structure, and the concave side of the baffle 5142 is set towards the inner cylinder 5141.

[0037] Specifically, the inner cylinder 5141 can be fixed to the inner wall of the gas-dissolving pipe 51 by means of a support plate, etc. Similarly, the baffle 5142 can be fixed to the inner wall of the gas-dissolving pipe 51 by means of a fixed support plate, etc., provided that the fluid can pass between the inner wall of the gas-dissolving pipe 51 and the inner cylinder 5141 (i.e., the outer annular cavity 517).

[0038] As an alternative implementation, see [link to implementation details]. Figure 2 As shown, the dissolved gas tube 51 also includes a Venturi tube gas-liquid pre-dispersion section 515, which is connected to the upper end of the straight tube section 512. The top of the Venturi tube gas-liquid pre-dispersion section 515 is a liquid phase inlet, and the middle part of the Venturi tube gas-liquid pre-dispersion section 515 is a throat 516. The throat 516 is connected to an injection tube 511, and a gas phase inlet is provided on the injection tube 511.

[0039] When pressurized wastewater flows through the Venturi tube gas-liquid pre-dispersion section 515 and enters the throat, according to Bernoulli's principle, its velocity increases sharply while its static pressure decreases significantly, creating a momentary local negative pressure zone at the throat. Ozone gas is precisely introduced into this negative pressure zone through the injection pipe 511. The high-speed water flow exerts a strong entrainment and shearing effect on the incoming ozone gas, instantly tearing and breaking it into a large number of tiny initial bubbles, which then form a violent turbulent mixture with the water flow. This process not only achieves preliminary gas dispersion but also greatly increases the initial surface area of ​​gas-liquid contact using the jet effect, laying the foundation for subsequent efficient dissolution.

[0040] In this embodiment, the dissolved gas pipe 51, through the coordinated action of jet crushing and axial circulation coupling, can overcome the technical bottleneck of conventional tank-type dissolved gas equipment in terms of short-time, low-pressure, and high-efficiency dissolved gas. It can achieve a dissolved gas efficiency of over 90% when the dissolved gas pressure is less than 0.3MPa and the dissolved gas time is less than 3.5s.

[0041] As an alternative implementation, see [link to implementation details]. Figure 1 and Figure 3 As shown, the vertical shallow cyclone flotation tank 6 includes a vertical tank body, a tangential inlet pipe, a cyclone flotation tank inner cylinder 67 located inside the vertical tank body, and an inclined plate assembly. The vertical tank body has a drain outlet 66 at its bottom and an exhaust outlet 63 and a slag outlet 64 at its top. The bottom end of the cyclone flotation tank inner cylinder 67 is connected to a sludge outlet 65. The tangential inlet pipe is horizontally positioned and connected to the cyclone flotation tank inner cylinder 67. The tangential inlet pipe has a tangential cyclone inlet 61, which is connected to a dissolved air release device 52. The inclined plate assembly is located above the cyclone flotation tank inner cylinder 67 and is used to coalesce small oil droplets and suspended impurities.

[0042] By employing a combined structure of tangential swirl and inclined plate components, the vertical shallow cyclone flotation tank 6 achieves the cascade separation of non-colloidal solid particles and the oxidative degradation of organic pollutants. The hydraulic residence time of a single vertical shallow cyclone flotation tank 6 does not exceed 210 seconds, and the hydraulic loading rate is greater than 45m. 3 / (m 2 ·h).

[0043] Among them, see Figure 1 and Figure 3As shown, the vertical shallow cyclone flotation tank 6 is connected to the inlet pipeline through the tangential cyclone inlet 61. Wastewater carrying ozone microbubbles enters the inner cylinder 67 of the cyclone flotation tank through the tangential cyclone inlet 61 for solid-liquid cyclone separation. The heavy components are discharged from the sludge discharge port 65 under the action of centrifugal sedimentation.

[0044] Specifically, under the powerful centrifugal force, denser particles in the water (such as sediment, inorganic precipitates, etc.) are thrown against the inner wall of the cyclone flotation tank 67. These particles, under the combined action of gravity and centrifugal force, spiral down the inner wall and eventually collect in the conical sludge discharge hopper at the bottom of the tank, where they are periodically or continuously discharged through the bottom sludge discharge port 65. This process constitutes the first stage of the "stage separation" concept of this equipment: pre-separation under the combined action of gravity and centrifugal force. This stage of separation effectively removes most of the heavy inorganic pollutants, thereby reducing the load on subsequent flotation separation units and preventing these heavy particles from interfering with the flotation process.

[0045] As an alternative implementation, see [link to implementation details]. Figure 3 The number of inclined plate assemblies is at least two sets, and each set of inclined plate assemblies is arranged at intervals around the axis of the vertical tank. The inclined plate assembly includes concentric frustum inclined plates 62. In each set of concentric frustum inclined plates 62, the concentric frustum inclined plates 62 are arranged at intervals in the vertical direction. The spacing between adjacent concentric frustum inclined plates 62 is equal or unequal, and there is a channel for fluid flow between adjacent concentric frustum inclined plates 62.

[0046] The concentric truncated cone inclined plate 62 enhances the separation efficiency through shallow settling. Light components such as suspended solids are discharged from the slag discharge port 64 under the synergistic effect of cyclone flotation and shallow settling of the concentric truncated cone component. The gas is discharged into the air after being treated by the ozone tail gas destroyer 7 through the exhaust port 63. The treated wastewater is discharged through the drain port 66.

[0047] As an alternative implementation, see [link to implementation details]. Figure 3 The inner cylinder 67 of the cyclone flotation tank has an open top, and the axis of the open top is collinear with the axis of the vertical tank body.

[0048] The above-described structure in this embodiment facilitates the overflow of the wastewater flow with lower density and most of the settled particles after cyclone pre-separation from the upper edge of the inner cylinder 67 of the cyclone flotation tank, which then enters the upper frustum-shaped inclined plate shallow sedimentation separation zone, i.e., the area where the inclined plate assembly is located.

[0049] As an alternative implementation, see [link to implementation details]. Figure 3 The concentric cone-shaped inclined plate 62 is set inclined downward along the axis away from the vertical tank body.

[0050] The concentric truncated cones 62 are parallel to each other and stacked one on top of the other, dividing the annular space of the tank into multiple independent, inclined, and narrow flow channels. When the wastewater carrying microbubbles enters these narrow flow channels, the typical shallow flotation separation principle begins to play a dominant role. Ozone microbubbles actively collide and adhere to suspended solids, flocs, oil droplets, and other floating particles in the water with densities similar to or slightly less than water, forming "bubble-particle" aggregates with densities much smaller than water. In the shallow separation channels, these aggregates only need to float a very short vertical distance (i.e., the vertical distance between adjacent truncated cones) to contact the lower surface of the upper truncated cone. Once in contact, they aggregate and merge here, forming larger scum particles, which slide rapidly upward along the inclined surface under the drive of buoyancy. All the scum on the concentric truncated cones 62 eventually collects in the scum collection area at the top of the tank, forming a stable scum layer, which is removed by a scraper or other device through the scum discharge port 64 at the top. This process constitutes the second stage of "tiered separation," namely, enhanced flotation separation for light pollutants. Simultaneously, during this process, some of the ozone dissolved in the water, as well as the bubbles themselves, act as strong oxidants, reacting chemically with dissolved organic pollutants in the water (characterized by chemical oxygen demand), oxidizing and decomposing them into smaller molecules, thereby achieving deep removal of dissolved pollutants.

[0051] After two-stage separation and ozone oxidation, the purified water is collected from the lower part of the concentric truncated cone inclined plate 62 region and discharged through the drain port 66 located at the lower part of the tank side wall. The small amount of unreacted ozone exhaust gas at the top of the tank is collected through the exhaust pipe and sent to the ozone exhaust gas destroyer 7 (e.g., by activated carbon adsorption or thermal decomposition) for harmless treatment to ensure that the gas emitted into the atmosphere meets environmental protection requirements.

[0052] In this embodiment, the vertical shallow cyclone flotation tank 6 adopts a combined internal structure of "tangential cyclone pre-separation + concentric truncated cone inclined plate 62 shallow sedimentation". It uses the cyclone centrifugal force field to promote the rapid sedimentation and separation of heavy particulate matter (such as mud and sand) and discharge it from the sludge discharge port 65. Then, the concentric truncated cone inclined plate 62 under the action of cyclone-opposite flow enhances the collision and adhesion between small-diameter and low-specific-gravity particulate matter (such as suspended solids, oil droplets, etc.) and microbubbles, so that suspended solids and oil phase are discharged from the slag discharge port 64 above the tank, realizing the stepwise separation of solid particles with different specific gravities and particle sizes. At the same time, ozone can simultaneously achieve advanced oxidation decomposition of organic pollutants in water during the process of dissolved gas bubble formation and transport. The treated end exhaust gas is discharged through the exhaust port 63 at the top of the vertical shallow cyclone flotation tank 6 and is discharged into the air after being treated by the ozone exhaust gas destroyer 7. The separated and degraded wastewater is discharged through the drain port 66 at the bottom of the side wall of the cyclone flotation tank.

[0053] The inventive concept of this embodiment includes two parts. First, based on the concept of enhanced mass transfer through micro-interface contact and internal circulation, ozone is miniaturized and the fluid is circulated in the conical hollow inner cylinder 514 within the dissolved gas tube 51 by the conical hollow inner cylinder 514, the flow port 518, and the outer annular cavity 517. This increases the residence time of the gas and improves the ozone mass transfer efficiency, thereby improving the utilization rate of ozone. The dissolved gas tube type microbubble generator 5 can overcome the bottleneck of short time and low pressure, achieving a dissolved gas efficiency of over 90% when the dissolved gas pressure is less than 0.3 MPa and the dissolved gas time is less than 3.5 s. At the same time, it can achieve efficient gas release through the ball valve (dissolved gas releaser 52) while achieving efficient gas dissolution, generating ozone microbubbles. Secondly, based on the concept of enhanced cyclone flotation through cyclone separation and shallow sedimentation, the vertical shallow cyclone flotation tank 6 can quickly achieve the stepwise separation of solid particles with different specific gravities and particle sizes through the synergistic coupling of tangential cyclone centrifugation and shallow sedimentation of the concentric frustum plate 62. It can quickly achieve multiple objectives such as slag discharge, removal of organic matter and suspended solids during operation.

[0054] Example 2: This embodiment provides a method for treating combined sewer overflow pollution, using the aforementioned ozone micro-flotation equipment. The vertical shallow cyclone flotation tank 6 includes a hollow inner cylinder cyclone separation zone and an upper frustum-shaped inclined plate shallow sedimentation separation zone. The method includes: S1. Wastewater is pressurized by pump 2 and enters the liquid phase inlet of the dissolved air tube microbubble generator 5. Ozone generated by ozone generator 3 is sent into the dissolved air tube 51 by ozone booster pump 4, where it generates initial bubbles under hydraulic shear. Subsequently, the bubble flow circulates around the conical hollow inner cylinder 514, the flow port 518, and the outer annular cavity 517 under inertial propulsion. Among them, the ozone generated by ozone generator 3 enters the gas phase inlet of the microbubble generator via ozone booster pump 4, and is sheared and broken at the throat 516 of the Venturi tube gas-liquid pre-dispersion section 515 to generate microbubbles, thereby increasing the specific surface area in the gas-liquid contact mass transfer process. Subsequently, the bubble flow enters the conical hollow inner cylinder 514, and under the synergistic effect of enhanced interface renewal in the inner annular flow, the residence time of the gas is increased, promoting the transmembrane dissolution of ozone molecules during the transport process and improving the dissolved air efficiency.

[0055] S2. The dissolved air water generated by the dissolved air pipe 51 is depressurized and released by the dissolved air release device 52 to generate ozone microbubbles. Then, it is carried by the sewage into the vertical shallow cyclone flotation tank 6 for liquid-solid centrifugal separation. Under the action of centrifugal sedimentation, the heavy components (mud, sand, etc.) solid particles are discharged from the bottom sludge discharge port 65.

[0056] S3. Under the action of the rotating wake of the cyclone separation zone in the hollow inner cylinder, the ozone microbubbles accelerate and collide with and adhere to suspended solid particles and oil droplets, forming an adhesus with a density less than water that floats to the surface. At the same time, the tiny oil droplets and suspended impurities aggregate and increase in the shallow sedimentation separation zone of the upper truncated cone-shaped inclined plate. S4. Discharge the treated wastewater and scum from different outlets.

[0057] In this process, ozone microbubbles, under the influence of the swirling wake of the inner cylinder 67 of the cyclone flotation tank, accelerate their adhesion to oil droplets and suspended particles, forming an adhesus with a density less than water, which then floats to the surface. Simultaneously, under shallow settling, the adhesus of oil droplets and other light solid particles, such as suspended matter, further coalesces and enlarges within the flow channel between adjacent concentric conical inclined plates 62, enhancing the separation effect. Subsequently, the scum is discharged through the upper scum outlet 64, thus achieving efficient, stepwise separation of solid particles with different specific gravities. The treated wastewater is discharged through the lower drain outlet 66 on the side wall.

[0058] Meanwhile, ozone is dissolved in a supersaturated jet within the dissolved air tube microbubble generator 5, generated through depressurized microbubble release, and decomposed into superoxide radicals and hydroxyl radicals during its transport within the vertical shallow cyclone flotation tank 6. Through the synergistic effect of direct ozone oxidation and free radical oxidation, advanced oxidative decomposition of recalcitrant organic pollutants is simultaneously achieved, further enhancing the system's separation capacity. The final exhaust gas is then treated by the ozone exhaust gas destroyer 7 after passing through the top exhaust port 63 before being discharged into the atmosphere.

[0059] The specific features, structures, or characteristics described in this specification may be combined in any suitable manner in one or more embodiments or examples.

[0060] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0061] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An ozone micro-flotation device, characterized in that, It includes an ozone generator, an ozone booster pump, and a water pump, a dissolved air tube microbubble generator, and a vertical shallow cyclone flotation tank connected sequentially along the water flow direction, wherein: The dissolved gas tube microbubble generator includes a dissolved gas tube and a cone-shaped hollow inner cylinder fixed inside the dissolved gas tube. The ozone generator is connected to the gas phase inlet of the dissolved gas tube through the ozone booster pump. An outer annular cavity is provided between the conical hollow inner cylinder and the inner wall of the dissolved gas tube. A flow port is opened at the bottom of the conical hollow inner cylinder, and the flow port is connected to the outer annular cavity. Part of the fluid injected into the dissolved gas tube can circulate around the conical hollow inner cylinder, the flow port and the outer annular cavity. The bottom of the dissolved gas pipe is provided with a dissolved gas water outlet, which is connected to the vertical shallow cyclone flotation tank through a dissolved gas release device.

2. The ozone micro-flotation device according to claim 1, characterized in that, The dissolved gas pipe includes a straight pipe section, and the conical hollow inner cylinder includes an inner cylinder body and a baffle, wherein: The inner cylinder and the baffle are both fixed inside the straight pipe section. The baffle is located below the bottom of the inner cylinder, and the flow port is formed between the inner cylinder and the baffle.

3. The ozone micro-flotation device according to claim 2, characterized in that, The baffle has an arc-shaped structure, and the concave side of the baffle faces the inner cylinder.

4. The ozone micro-flotation device according to claim 2, characterized in that, The dissolved gas tube also includes a Venturi tube gas-liquid pre-dispersion section, which is connected to the upper end of the straight pipe section. The top of the Venturi tube gas-liquid pre-dispersion section is the liquid phase inlet, and the middle part of the Venturi tube gas-liquid pre-dispersion section is the throat. The throat is connected to a gas injection pipe, and the gas injection pipe is provided with a gas phase inlet.

5. The ozone micro-flotation device according to claim 1, characterized in that, The vertical shallow cyclone flotation tank includes a vertical tank body, a tangential inlet pipe, an inner cylinder of the cyclone flotation tank located within the vertical tank body, and an inclined plate assembly, wherein: The bottom of the vertical tank is provided with a drain outlet, the upper part of the vertical tank is provided with an exhaust outlet and a slag discharge outlet, the exhaust outlet is connected to an ozone tail gas destroyer, and the bottom of the inner cylinder of the cyclone flotation tank is connected to a sludge discharge outlet. The tangential water inlet pipe is horizontally arranged and connected to the inner cylinder of the cyclone flotation tank. The tangential water inlet pipe has a tangential cyclone water inlet, which is connected to the dissolved gas release device. The inclined plate assembly is located above the inner cylinder of the cyclone flotation tank and is used to coalesce tiny oil droplets and suspended impurities.

6. The ozone micro-flotation device according to claim 5, characterized in that, The number of inclined plate assemblies is at least two sets, and each set of inclined plate assemblies is arranged at intervals around the axis of the vertical tank.

7. The ozone micro-flotation device according to claim 5, characterized in that, The inclined plate assembly includes concentric frustum inclined plates. In each group of concentric frustum inclined plates, the concentric frustum inclined plates are arranged at intervals along the vertical direction. The spacing between adjacent concentric frustum inclined plates is equal or unequal, and there is a channel for fluid flow between adjacent concentric frustum inclined plates.

8. The ozone micro-flotation device according to claim 5, characterized in that, The inner cylinder of the cyclone flotation tank has an open top, and the axis of the open top is collinear with the axis of the vertical tank body.

9. The ozone micro-flotation device according to claim 7, characterized in that, The concentric cone-shaped inclined plate is inclined downward along the axis away from the vertical tank body.

10. A method for treating combined sewer overflow pollution, characterized in that, Using the ozone micro-air flotation device according to any one of claims 1-9, the vertical shallow cyclone flotation tank includes a hollow inner cylinder cyclone separation zone and an upper frustum-shaped inclined plate shallow sedimentation separation zone, the method comprising: S1. After the wastewater is pressurized by the water pump, it enters the liquid phase inlet of the dissolved air tube microbubble generator. The ozone generated by the ozone generator is sent into the dissolved air tube through the ozone booster pump, and initial bubbles are generated under the action of hydraulic shear. Subsequently, the bubble flow circulates around the cone-shaped hollow inner cylinder, the flow port and the outer ring cavity under the inertial boost. S2. The dissolved air water generated through the dissolved air pipe is depressurized and released by the dissolved air releaser to generate ozone microbubbles. Then, it is carried by the sewage into the vertical shallow cyclone flotation tank for liquid-solid centrifugal separation. The separated heavy component particles such as mud and sand are discharged from the bottom sludge discharge port. S3. Under the action of the rotating wake of the cyclone separation zone of the hollow inner cylinder, the ozone microbubbles accelerate and collide with and adhere to suspended solid particles and oil droplets, forming an adhesus with a density less than water that floats to the surface. At the same time, the tiny oil droplets and suspended impurities aggregate and increase in the shallow sedimentation separation zone of the upper truncated cone-shaped inclined plate. S4. Discharge the treated wastewater and scum from different outlets.

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