Low-pressure driven rotational flow reinforced efficient anaerobic reaction device and working method thereof

Abstract

The invention relates to a low-pressure driven rotational flow reinforced efficient anaerobic reaction device and a working method thereof, and belongs to the technical field of anaerobic wastewater treatment. The conical section of the reactor is provided with a reactor inlet pipe communicated with a raw sewage treatment system; a three-phase separator is arranged at the upper end in the cylindrical section of the reactor, the three-phase separator is communicated with an effluent weir and a biogas collecting pipe, and an inclined baffle is used for intercepting rising granular sludge and enabling the granular sludge to flow back along the cylinder wall; a central pipe is arranged at the axis of the reactor along the axial direction; and the bottom of the central pipe is communicated with the sludge recovery system. The sludge-matrix contact efficiency and the biological reaction rate are improved, timely trapping and separation of light sludge and suspended solids are achieved, the effluent stability is improved, system starting is accelerated, the form and function of granular sludge are enhanced, the granular sludge proportion and the system treatment efficiency are improved, and the economical efficiency and the engineering application value are improved; finally, efficient, stable and low-cost anaerobic wastewater treatment is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to a low-pressure driven cyclone enhanced high-efficiency anaerobic reaction device and its working method, belonging to the technical field of anaerobic wastewater treatment. BACKGROUND

[0002] In the prior art, the UASB (Upflow Anaerobic Sludge Bed) reactor mainly relies on the hydraulic disturbance of the influent and the biodegradation of the produced biogas to maintain the internal mixing state. However, this mixing method is not efficient, which easily leads to uneven flow field inside the reactor, forming mass transfer resistance. In the high-concentration sludge bed area, the substrate and microorganisms do not contact sufficiently, which limits the biological reaction rate and the overall treatment efficiency. The uneven flow field can also cause problems such as reduction of sludge activity, formation of dead zones, and affect the volume utilization rate of the reactor. Especially under low substrate concentration conditions, the reduction of biogas production will further exacerbate the problems of insufficient mixing, hydraulic dead zones, and low treatment efficiency.

[0003] In addition, the existing UASB flow field design is mostly slow upward flow, which is difficult to provide stable and controllable hydraulic conditions, and lacks effective means to strengthen the granulation process, resulting in slow system startup. In long-term operation, the granular sludge may be broken due to local high hydraulic shear force, producing a large amount of light floc sludge. Such sludge has poor settling performance and is easily lost with the effluent, causing sludge loss and reduction of system stability, especially in IC reactors (Internal Circulation Anaerobic Reactor) with large height-to-diameter ratio. The above problems directly lead to unstable effluent quality, with suspended solids and chemical oxygen demand exceeding the standard. At the same time, the traditional UASB has limited treatment capacity for high content of suspended solids in the influent, and usually needs to add a sand trap or other pretreatment unit at the front end, increasing the complexity of the process flow, capital investment and land occupation.

[0004] To solve the above problems, some solutions have been proposed in the prior art. The "Circular UASB water distribution device" with publication number CN204173981U improves the influent uniformity by cyclone water distribution, improving the UASB treatment efficiency, but does not strengthen the formation of granular sludge and the mass transfer process. The "Improved UASB anaerobic reactor" with publication number CN213446442U solves the problems of water distribution pipe blockage and sludge discharge, but does not solve the problem of system instability caused by granular sludge breakage. The "UASB sludge cyclone separator and its matching UASB sludge treatment system" with publication number CN212982717U strengthens the flow field by tangential influent induced cyclone, which can treat high suspended solid wastewater, but relies on additional high energy consumption equipment and addition of flocculants, precipitants and other chemical agents, which is not suitable for traditional UASB reactor modification, and the non-integrated design destroys the integrity of the UASB process, increasing the land occupation.

[0005] Hydrocyclone technology has the advantages of strong mixing, strong mass transfer, strong separation and strong shearing. In recent years, researches have shown that it can strengthen the sludge granulation process and help UASB reactor to achieve higher and more stable performance. SUMMARY

[0006] To solve the problems in the background art, the application provides a low-pressure driven hydrocyclone enhanced high-efficiency anaerobic reaction device and a working method thereof.

[0007] To achieve the above-mentioned purposes, the application adopts the following technical solution: a low-pressure driven hydrocyclone enhanced high-efficiency anaerobic reaction device, comprising a primary sewage treatment system, a hydrocyclone reaction system, a sludge-water separation system and a sludge recovery system. The hydrocyclone reaction system comprises a bracket and a reactor; the reactor comprises a reactor cylindrical segment fixed at the upper part by welding and a reactor conical segment at the lower part, the side wall of the reactor conical segment is provided with a reactor inlet pipe arranged tangentially, the reactor inlet pipe is arranged in communication with the primary sewage treatment system, and the lower end of the reactor is provided with the bracket; The sludge-water separation system comprises a three-phase separator, a water outlet weir and a biogas collection pipe; the three-phase separator is installed at the upper end inside the reactor cylindrical segment, the guide cylinder of the three-phase separator is arranged in communication with the water outlet weir, the gas cap of the three-phase separator is arranged in communication with the biogas collection pipe, and the inclined baffle of the three-phase separator is used for intercepting the rising granular sludge and making it backflow along the cylinder wall; A central pipe is arranged axially at the axis of the reactor, and a gap is left between the top end of the central pipe and the three-phase separator, and the bottom of the central pipe is arranged in communication with the sludge recovery system.

[0008] Further, the sludge recovery system is a light sludge collection pipe, one end of the light sludge collection pipe is arranged in communication with the bottom of the central pipe.

[0009] Alternatively, the sludge recovery system comprises a light sludge collection pipe and an agglomeration hydrocyclone arranged obliquely; the agglomeration hydrocyclone comprises a hexagonal prism segment, a hexagonal pyramid segment, an agglomeration hydrocyclone underflow pipe, an agglomeration hydrocyclone overflow pipe and a baffle; The upper end of the hexagonal pyramid segment is fixed with the lower end of the hexagonal prism segment by welding, the agglomeration hydrocyclone underflow pipe at the bottom end of the hexagonal pyramid segment is arranged in communication with the side wall of the reactor conical segment through the light sludge collection pipe, the upper end of the hexagonal prism segment is provided with the agglomeration hydrocyclone overflow pipe, the agglomeration hydrocyclone inlet pipe tangentially arranged on the side wall of the hexagonal prism segment is arranged in communication with the bottom of the central pipe, each inner wall surface of the hexagonal prism segment is provided with an obliquely arranged baffle, the included angle of each baffle and the corresponding inner wall surface is the same, the height of each baffle is the same as the height of the hexagonal prism segment, and the agglomeration hydrocyclone inlet pipe, the agglomeration hydrocyclone underflow pipe and the agglomeration hydrocyclone overflow pipe are all hexagonal prism structures.

[0010] Further, the inlet end of the central pipe is funnel-shaped.

[0011] Further, the lower part of the inner wall of the reactor cylindrical section is a spiral wall surface.

[0012] Further, the device further comprises an external cyclone, which comprises an upper and lower fixed external cyclone cylindrical section and an external cyclone conical section, the tangential external cyclone inlet pipe of the side wall of the external cyclone cylindrical section is communicated with the lower part of the reactor conical section through a flow guide pipe, the external cyclone overflow pipe at the upper end of the external cyclone cylindrical section is communicated with the connection between the reactor conical section and the reactor cylindrical section through a backflow pipe, and the lower end of the external cyclone conical section is provided with an external cyclone underflow pipe.

[0013] Further, the number of reactor inlet pipes is at least one.

[0014] Further, the outlet of the central pipe is provided with a cleaning interface.

[0015] A working method of a low-pressure driving cyclone-enhanced high-efficiency anaerobic reaction device according to the present application, the method comprising the following steps: S1: the sewage in the primary sewage treatment system is tangentially injected into the reactor conical section through the reactor inlet pipe, and the sewage generates high-speed cyclone along the side wall in the reactor conical section due to the tangential water inlet effect and rises along the axial direction; S2: under the action of the shearing force of the high-speed cyclone, heavy granular sludge is thrown to the inner wall surface to remain, light sludge and suspended matter are dispersed by shearing to gather in the center, and sludge and sewage undergo anaerobic reaction to produce biogas; S3: under the joint promotion of biogas and high-speed cyclone, heavy granular sludge and light sludge and suspended matter rise together in cyclone, the heavy granular sludge continues to move along the side wall, and the light sludge and suspended matter are in the central area; S4: when the water flow enters the spiral wall surface of the reactor cylindrical section, the mixed liquid rises along the spiral wall surface, the spiral wall surface compensates and maintains the cyclone field, so that the liquid flow still maintains a relatively strong tangential velocity, at the same time, the spiral wall surface generates local vortex flow in the flow guiding process, drives the sludge particles to rotate and entangle, promotes the agglomeration and granulation of flocculent sludge, and the wall surface attached sludge also falls off due to the shearing action and participates in the circulation mixing; S5: when the water flow reaches above the reactor cylindrical section, the three-phase separator starts gas-liquid-solid separation, biogas enters the biogas collection pipe through the gas cap and is discharged, and clarified water is guided into the outlet weir by the flow guide cylinder, due to the continuous cyclone effect, the heavy granular sludge settles back along the inclined baffle of the three-phase separator and remains in the reactor side wall, the light sludge and suspended matter are concentrated in the central area, and the light sludge and suspended matter are pressed into the central pipe to the agglomeration cyclone by using the low-pressure area of the cyclone center; S6: Agglomeration hydrocyclones are used to optimize sludge communities and separate light sludge. S601: The return sludge mixture enters the inlet pipe of the agglomeration hydrocyclone from the central pipe. The gravitational potential energy is converted into tangential kinetic energy by the tangential flow, causing the sludge mixture to rotate in the agglomeration hydrocyclone to form a rotating flow. S602: The sludge mixture is guided and disturbed by the inclined baffles in the hexagonal section, generating a strong and uniform rotating flow. At the inner corners of the hexagon and the trailing edge of the baffle, the magnitude and direction of the water flow velocity will differ from those of the adjacent water flow, thus forming a velocity gradient in a local area. S603: Small-scale eddies are formed inside the hydrocyclone. Due to the interaction of the rotating flow and the small-scale eddies, the flocculent sludge collides and entangles with each other. The sludge will rotate in the hydrocyclone, thereby inducing micro-interface oscillation, which together promotes the further aggregation of flocculent sludge. At the same time, the high shear force in the small-scale eddies causes some small-diameter suspended solids to desorb from the sludge surface. S604: In the overall swirling field of the hydrocyclone, due to the centrifugal force generated by tangential kinetic energy, sludge with high density and good agglomeration effect gathers towards the wall and enters the underflow pipe of the agglomerating hydrocyclone with the outer swirling flow. Loose or poor-performing sludge and small-diameter suspended solids gather towards the center and rise with the inner swirling flow, and are discharged through the overflow pipe of the agglomerating hydrocyclone, thereby achieving the optimization of the sludge mass and the separation of light sludge.

[0016] S7: When the system treats wastewater containing large suspended solid particles, the sludge mixture in the conical section of the reactor is pumped into an external hydrocyclone. Gravel is discharged through the underflow pipe of the external hydrocyclone, and sludge is returned to the junction of the cylindrical section and the conical section of the reactor through the overflow pipe of the external hydrocyclone.

[0017] Compared with the prior art, the beneficial effects of the present invention are: This invention generates high-intensity swirling flow through tangential inlet at the cone bottom, enhancing mass transfer and mixing within the sludge bed, improving sludge-matrix contact efficiency and biological reaction rate, and increasing adaptability to low-temperature and low-load conditions. The synergistic effect of the central tube and three-phase separator enables timely collection and separation of light sludge and suspended solids, preventing effluent quality fluctuations caused by sludge loss and improving effluent stability. The spiral wall maintains the tangential velocity of the swirling field, combined with local eddies to promote flocculent sludge aggregation and granulation, accelerating system startup and enhancing the morphology and function of granular sludge. An integrated agglomeration cyclone optimizes the sludge mass structure, achieving sludge classification through centrifugal force and small-scale eddies, increasing the proportion of granular sludge and system treatment efficiency. An external cyclone treats large suspended solid particles, simplifying the front-end pretreatment unit, reducing process complexity and infrastructure investment. Overall, the reactor height-to-diameter ratio requirement is reduced, decreasing civil engineering and pumping costs, improving economic efficiency and engineering application value, ultimately achieving efficient, stable, and low-cost anaerobic wastewater treatment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention; Figure 3 This is a schematic diagram of the structure of Embodiment 4 of the present invention; Figure 4 This is a schematic diagram of the structure of Embodiment 5 of the present invention; Figure 5 This is a schematic diagram of an agglomeration cyclone, where: (a) is the front view; (b) is the right view; and (c) is the top view. Figure 6 This is a schematic diagram of the structure of multiple reactor inlet pipes. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] Example 1: A low-pressure driven cyclone-enhanced high-efficiency anaerobic reactor includes a raw wastewater treatment system, a cyclone reaction system, a sludge-water separation system, and a sludge recovery system. The raw wastewater treatment system includes a raw wastewater tank 1, an inlet pump 2, a liquid flow meter 3, and a first check valve 4. The raw wastewater tank 1 is connected to the cyclone reaction system via pipelines that sequentially connect the inlet pump 2, the liquid flow meter 3, and the first check valve 4. The inlet pump 2 increases the water pressure in the reactor inlet pipe 5, thereby causing the wastewater to be jetted into the reactor conical section 9 of the cyclone reaction system at a certain tangential velocity. The swirling reaction system includes a bracket 8 and a reactor; the reactor includes a cylindrical reactor section 10 located at the upper part and a conical reactor section 9 located at the lower part, which are fixed by welding. The side wall of the conical reactor section 9 is provided with a tangentially arranged reactor inlet pipe 5. The reactor inlet pipe 5 is connected to the first check valve 4 of the original sewage treatment system. The lower end of the reactor is fixedly provided with a bracket 8. The sludge-water separation system includes a three-phase separator 13, an effluent weir 14, and a biogas collection pipe 15. The three-phase separator 13 is installed at the upper end inside the cylindrical section 10 of the reactor. The guide tube of the three-phase separator 13 is connected to the effluent weir 14, and the gas cap of the three-phase separator 13 is connected to the biogas collection pipe 15. A third check valve 16 is provided on the biogas collection pipe 15. The inclined baffle of the three-phase separator 13 is used to intercept the rising granular sludge and allow it to flow back along the cylinder wall. The cross-sectional area of ​​the three-phase separator gradually increases to ensure that the water flow velocity in the low-intensity swirling zone is reduced, which is conducive to gas-liquid-solid separation. The above are all existing technologies and will not be described in detail. The ratio of the length of the cylindrical section 10 of the reactor to the length of the conical section 9 of the reactor, as well as the cone angle of the conical section 9 of the reactor, can be modified according to the actual wastewater conditions.

[0021] A central tube 11 is axially arranged at the center of the reactor. A gap is left between the top end of the central tube 11 and the three-phase separator 13, and the bottom end of the central tube 11 is connected to the sludge recovery system. The height of the gap between the top end of the central tube 11 and the three-phase separator 13, as well as the diameter of the central tube 11, can be adjusted according to actual conditions.

[0022] Furthermore, the sludge recycling system is a light sludge collection pipe 7, one end of which is connected to the bottom of the central pipe 11, and a second check valve 6 is provided on the light sludge collection pipe 7.

[0023] Furthermore, the number of reactor inlet pipes 5 can be set to at least one according to the actual swirling intensity requirements, and the tangential angle between the tangential water inlet and the conical sidewall is β, such as... Figure 6 As shown.

[0024] Furthermore, the outlet of the central tube 11 is provided with a cleaning port for periodically flushing the inner wall of the central tube to prevent blockage.

[0025] All check valves in this invention are made of corrosion-resistant materials and can be opened or closed by an automated control system, thereby regulating the influent flow rate, the frequency of light sludge discharge, and biogas collection.

[0026] Example 2: The difference between this embodiment and Embodiment 1 is that: The sludge recovery system includes a light sludge collection pipe 7 and a gravity-driven, hexagonal, inclined agglomeration hydrocyclone; the inclination angle α can be adjusted according to the sludge concentration and particle size. The agglomeration hydrocyclone is used to enhance the agglomeration of light sludge, separate light sludge with poor separation performance and small-diameter suspended solids, and recover flocculent sludge with better recovery performance to the reactor. The aim is to further enhance and recover valuable light sludge, preventing loss; and to separate flocculent sludge and small-diameter suspended solids with poor screening function, preventing them from affecting the reactor's treatment efficiency. Figure 2As shown, the agglomeration cyclone includes a hexagonal section 18, a hexagonal pyramidal section 19, an agglomeration cyclone underflow pipe 20, an agglomeration cyclone overflow pipe 21, and a baffle 22. The upper end of the hexagonal pyramidal segment 19 is welded and fixed to the lower end of the hexagonal spherical segment 18. The agglomeration hydrocyclone underflow pipe 20 at the bottom end of the hexagonal pyramidal segment 19 is connected to the side wall of the reactor conical segment 9 through the light sludge collection pipe 7. The light sludge collection pipe 7 is equipped with a second check valve 6. The upper end of the hexagonal spherical segment 18 is equipped with an agglomeration hydrocyclone overflow pipe 21. The agglomeration hydrocyclone inlet pipe 17, which is tangentially arranged on the side wall of the hexagonal spherical segment 18, is connected to the bottom of the central pipe 11. The central pipe 11 is equipped with a fourth check valve 23. Each inner wall surface of the hexagonal spherical segment 18 is equipped with an inclined baffle 22. The included angle between each baffle 22 and the corresponding inner wall surface is the same. The height of each baffle 22 is the same as the height of the hexagonal spherical segment 18. The angle and width of the baffle 22 are adjustable. The agglomeration hydrocyclone inlet pipe 17, the agglomeration hydrocyclone underflow pipe 20, and the agglomeration hydrocyclone overflow pipe 21 are all hexagonal structures.

[0027] Compared to traditional circular hydrocyclones, the hexagonal agglomerating hydrocyclone of this invention can generate more small-scale eddies in the internal flow field, enhancing the micro-turbulence of the sludge mixture and promoting the agglomeration of flocculent sludge. The agglomerating hydrocyclone induces a large number of eddies internally, thus agglomerating sludge while maintaining a large underflow split ratio. The inner surfaces of the hexagonal pyramidal section 19 and the underflow tube 20 of the agglomerating hydrocyclone are both processed with hydrophobic materials.

[0028] Example 3: The difference between this embodiment and Embodiment 2 is as follows: The inlet end of the central tube 11 has a funnel-shaped structure.

[0029] In a swirling flow field, a low-pressure zone naturally forms in the central region due to the low tangential velocity and large pressure gradient. Light sludge and fine suspended solids tend to accumulate in this area. Traditional straight-pipe central tubes have a limited collection range, making it difficult for some light sludge to enter in time, and it is easily lost with the effluent.

[0030] The flared end of the funnel-shaped central tube increases the collection cross-section and creates a guiding effect in the flow field, allowing light sludge and suspended particles gathered in the central low-pressure zone to flow more smoothly into the central tube, thus achieving more efficient collection. Therefore, the design of the funnel-shaped central tube aims to enhance the separation of granular sludge and flocculent sludge, reduce the chance of granular sludge entering the central tube, further promote the degassing of biogas attached to the sludge, expand the collection cross-section, increase the probability of light sludge and small-diameter suspended solids entering the central tube, and reduce the risk of blockage at the central tube opening.

[0031] The angle of the funnel shape, the diameter of the central tube, and the distance from the three-phase separator are all adjustable.

[0032] Example 4: The difference between this embodiment and embodiment 3 is as follows: The lower part of the inner wall of the cylindrical section 10 of the reactor is a spiral wall or has protrusions, such as Figure 3 As shown, the purpose is to promote the generation of local eddies and prevent sludge from scaling on the wall surface.

[0033] In the cylindrical section 10 of the reactor, the rotational intensity gradually decreases as the water flows upward, which can easily lead to insufficient mixing and insufficient granulation momentum. By changing the inner wall to a spiral structure, the liquid flow is forced to move along the spiral guide during the upward process, thereby maintaining tangential velocity and rotational momentum. The spiral wall surface also forms small-scale eddies locally due to the velocity difference with the surrounding fluid, promoting relative motion and collision between particles and improving mixing and aggregation. The small-scale eddies also cause the sludge adhering to the wall surface to detach, which can increase its biomass and extend its operating cycle.

[0034] Therefore, the design of the spiral wall aims to change its velocity distribution, induce the generation of internal eddies, compensate for the swirling attenuation caused by the increased cross-section, form appropriate hydraulic shear, and promote sludge granulation; enhance selective pressure, increase radial and tangential components, which allows higher density particles to remain against the wall, while lighter particles are gathered in the center, and finally undergo secondary enhancement by gravity-driven hydrocyclones; generating more eddies is beneficial for the removal of sludge from the wall and extends the operating cycle.

[0035] Example 5: The difference between this embodiment and embodiment 4 is that: The device also includes an external hydrocyclone, which comprises a cylindrical section 26 and a conical section 27 welded and fixed at the top and bottom. An external hydrocyclone inlet pipe 25, tangentially disposed on the side wall of the cylindrical section 26, is connected to the lower part of the conical section 9 of the reactor via a drain pipe 30. The drain pipe 30 is equipped with a sludge pump 35 and a fifth check valve 36. An external hydrocyclone overflow pipe 29 at the upper end of the cylindrical section 26 is connected to the connection between the conical section 9 and the cylindrical section 10 of the reactor via a return pipe 31. The return pipe 31 is equipped with a second sludge pump 32, a second flow meter 33, and a sixth check valve 34. An external hydrocyclone underflow pipe 28 is located at the lower end of the conical section 27.

[0036] The geometry of the external hydrocyclone, including the cone angle and column-to-cone ratio, needs to be optimized to obtain an ideal overflow split ratio and good solid-liquid separation performance.

[0037] External hydrocyclones are suitable for applications where the removal of large suspended solids at the reactor front end is insufficient. They effectively remove large suspended solids and, during the reactor granulation stage, screen and agglomerate the sludge, thereby shortening the start-up time of granular sludge.

[0038] The inner surfaces of the conical section of the external cyclone separator and the underflow tube are both machined with hydrophobic materials, while the inner surface of the cylindrical section of the built-in cyclone activator is machined with a hydrophilic material.

[0039] The height difference between the inlet of the diversion pipe 30 and the top of the central pipe is greater than the height difference between the underflow pipe of the agglomeration hydrocyclone and the return port of the side wall of the conical section of the reactor.

[0040] The present invention discloses a method for operating a low-pressure driven cyclone-enhanced high-efficiency anaerobic reactor, the method comprising the following steps: S1: Wastewater from the raw wastewater tank 1 of the raw wastewater treatment system, pressurized by the inlet pump 2, is injected tangentially into the conical section 9 of the reactor through the inlet pipe 5 at a specific rate. Guided by the bottom wall of the cone, the influent momentum creates a strong swirling flow inside the reactor. This swirling flow field is the fundamental driving force for achieving the various functions of this invention. By adjusting the influent flow rate using the liquid flow meter 3, the wastewater, due to the tangential influent action, generates a high-speed swirling flow along the sidewalls within the conical section 9 of the reactor and rises axially, forming a granular sludge bed of a certain height. The swirling intensity is greatest near the inlet and at the bottom of the cone. The strong shear force, while preventing the granular sludge from breaking up, promotes thorough mixing of the sludge bed and wastewater, greatly improving the mass transfer effect. Simultaneously, the strong centrifugal force throws the high-density granular sludge towards the bottom wall of the cone, synergistically promoting the screening of dense sludge with the shear force. The lower part of the conical section 9 of the reactor is a high-intensity swirling zone, the middle part of the cylindrical section 9 is a medium-intensity swirling zone, and the upper part of the cylindrical section 9 is a low-intensity swirling zone.

[0041] S2: Under the shearing force of the high-speed swirling flow, heavy granular sludge that can resist the shearing force is thrown to the inner wall and retained, while light sludge and suspended solids with weaker resistance are sheared and dispersed and aggregate towards the center. At the same time, thanks to the strong mixing effect of the swirling flow, the sludge and sewage maintain good mass transfer, which creates favorable conditions for methanogenic bacteria, thereby causing anaerobic reaction to produce biogas 12. S3: Driven by biogas 12 and high-speed swirl, heavy granular sludge, light sludge and suspended solids rise together in a swirling motion. The heavy granular sludge continues to move along the side wall, while the light sludge and suspended solids are in the central area. S4: When the water flows into the spiral wall of the cylindrical section 10 of the reactor, the swirling intensity and shear force decrease due to the increased cross-sectional area of ​​the flow channel. At this time, the shear force is moderate, which can maintain a good mixing effect without causing the granular sludge to break down. Instead, it can promote the re-agglomeration and granulation of flocculent sludge. At this time, the granular sludge gathers near the wall due to the large centrifugal force, while the light sludge gathers near the central tube. The partitioning of granular sludge and flocculent sludge reduces the chance of flocculent sludge entering the sedimentation zone through the return slit, thereby reducing the probability of sludge loss and promoting further granulation of granular sludge. The mixed liquid rises along the spiral wall, and the spiral wall compensates for and maintains the swirling flow field, so that the liquid flow still maintains a strong tangential velocity. At the same time, the spiral wall generates local eddies during the flow guidance process, which drives the sludge particles to rotate and entangle, promoting the agglomeration and granulation of flocculent sludge. The sludge attached to the wall also falls off due to the shearing action and participates in the circulation mixing. S5: When the water reaches the top of the cylindrical section 10 of the reactor, the swirling intensity further decreases, and the water flow velocity is significantly reduced. The three-phase separator 13 begins gas-liquid-solid separation of granular sludge, water, and biogas. Biogas 12 enters the biogas collection pipe 15 through the gas cap and is discharged. Clarified water is guided through the guide tube to the effluent weir 14 and flows to the next treatment unit. Due to the continuous swirling effect, the heavy granular sludge, due to its higher density, settles and flows back along the inclined baffle of the three-phase separator 13 and remains on the side wall of the reactor, descending axially near the wall. Light sludge and suspended solids are concentrated in the central area. Therefore, the chance of flocculent sludge entering the sedimentation zone above the three-phase separator 13 through the return slit is reduced, thus reducing the risk of sludge loss. Secondly, due to the high flow velocity and low pressure at the central pipe, under the action of pressure difference, the sludge is forced into the central pipe 11 and discharged to the agglomeration cyclone using the low-pressure zone at the center of the swirling flow, ensuring that the sludge is not lost with the effluent, thereby obtaining stable high-quality effluent. In a rotating flow field, according to fluid mechanics principles, a low-pressure zone forms in the central axis region due to the lower fluid velocity. The central pipe utilizes this low-pressure zone to draw in lightweight flocculent sludge generated from particle breakage, as well as suspended solids and other low-density substances from the influent. These lightweight materials are not easily thrown to the periphery under centrifugal force; instead, they tend to accumulate in the low-pressure central region. Through the central pipe, these lightweight materials can be discharged periodically or continuously, thus achieving effective removal of suspended solids and flocculent sludge without affecting the main biological reaction and sludge-water separation. This fundamentally solves the problem of unstable effluent quality caused by sludge loss.

[0042] The umbrella-shaped baffles guide the flow, allowing biogas to be fully desorbed and discharged. Due to the relatively weak swirling intensity in this area, some granular sludge that escapes to the vicinity of the central pipe will settle due to inertia or enter the sedimentation zone along the inclined baffles after degassing, thus effectively recovering it to the reactor body. Conversely, incompletely degassed light sludge continues to rise with the liquid flow and is eventually sucked in and discharged by the central pipe; some degassed light sludge that is still in the central low-pressure zone will also enter the central pipe due to inertia, thus achieving selective collection and discharge of light sludge.

[0043] S6: Agglomeration hydrocyclones are used to optimize sludge communities and separate light sludge. S601: The return sludge mixture enters the inlet pipe 17 of the agglomeration hydrocyclone from the central pipe 11. The gravitational potential energy is converted into tangential kinetic energy by the tangential flow, causing the sludge mixture to rotate in the agglomeration hydrocyclone to form a rotating flow. S602: The sludge mixture is guided and disturbed by the inclined baffle 22 in the hexagonal section 18, generating a strong and uniform rotating flow. At the inner corner of the hexagon and the tail edge of the baffle, the magnitude and direction of the water flow velocity will differ from the adjacent water flow, thus forming a velocity gradient in a local area. S603: Under this velocity gradient, small-scale eddies are formed within the hydrocyclone. These small-scale eddies enhance the relative motion and collisions between particles at the microscopic level. Due to the interaction of the rotating flow and the small-scale eddies, the flocculent sludge collides and entangles, causing the sludge to rotate within the hydrocyclone, thereby inducing micro-interface oscillations and further promoting the aggregation of flocculent sludge. Science of the Total Environment, 845 (2022) 157224 verifies that swirling can induce particle rotation, induce micro-interface oscillations, and thus enhance sludge settling velocity sorting, promoting granulation. Simultaneously, the high shear force in the small-scale eddies causes some small-diameter suspended solids to desorb from the sludge surface, improving the solid-liquid separation effect. S604: In the overall swirling field of the hydrocyclone, due to the centrifugal force generated by tangential kinetic energy, sludge with high density and good agglomeration effect gathers towards the wall and enters the underflow pipe 20 of the agglomerating hydrocyclone with the outer swirling flow. Loose or poor-performing sludge and small-diameter suspended solids gather towards the center and rise with the inner swirling flow, and are discharged through the overflow pipe 21 of the agglomerating hydrocyclone, thereby achieving the optimization of the sludge mass and the separation of light sludge.

[0044] S7: When the system is treating wastewater containing large suspended solid particles, start sludge pump 32 to pump 5%-10% of the sludge mixture in the conical section 9 of the reactor into the external hydrocyclone. Under the action of the three-dimensional swirling field, separation is achieved by relying on the particle density difference. Gravel and sludge are separated in the external hydrocyclone. About 20% of the gravel is discharged through the underflow pipe 28 of the external hydrocyclone, and the remaining about 80% of the granular sludge mixture is returned to the junction of the cylindrical section 10 and the conical section 9 of the reactor through the overflow pipe 29 of the external hydrocyclone.

[0045] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A low-pressure driven cyclone-enhanced high-efficiency anaerobic reactor, comprising a raw wastewater treatment system, a cyclone reaction system, a sludge-water separation system, and a sludge recovery system; The swirling reaction system includes a bracket (8) and a reactor; the reactor includes a cylindrical reactor section (10) located at the top and a conical reactor section (9) located at the bottom, which are fixed by welding. The side wall of the conical reactor section (9) is provided with a tangentially arranged reactor inlet pipe (5). The reactor inlet pipe (5) is connected to the original sewage treatment system. The lower end of the reactor is provided with a bracket (8). The sludge-water separation system includes a three-phase separator (13), an effluent weir (14), and a biogas collection pipe (15); the three-phase separator (13) is installed at the upper end inside the cylindrical section (10) of the reactor, the guide tube of the three-phase separator (13) is connected to the effluent weir (14), the gas cap of the three-phase separator (13) is connected to the biogas collection pipe (15), and the inclined baffle of the three-phase separator (13) is used to intercept the rising granular sludge and make it flow back along the cylinder wall; Its features are: A central tube (11) is provided along the axial direction at the center of the reactor. A gap is left between the top of the central tube (11) and the three-phase separator (13). The bottom of the central tube (11) is connected to the sludge recovery system.

2. The low-pressure driven cyclone-enhanced high-efficiency anaerobic reactor according to claim 1, characterized in that: The sludge recycling system is a lightweight sludge collection pipe (7), one end of which is connected to the bottom of the central pipe (11).

3. The low-pressure driven cyclone-enhanced high-efficiency anaerobic reactor according to claim 1, characterized in that: The sludge recycling system includes a light sludge collection pipe (7) and an inclined agglomeration hydrocyclone; the agglomeration hydrocyclone includes a hexagonal section (18), a hexagonal pyramidal section (19), an agglomeration hydrocyclone underflow pipe (20), an agglomeration hydrocyclone overflow pipe (21), and baffles (22). The upper end of the hexagonal pyramid segment (19) is welded and fixed to the lower end of the hexagonal spherical segment (18). The agglomeration hydrocyclone underflow pipe (20) at the bottom end of the hexagonal pyramid segment (19) is connected to the side wall of the reactor conical segment (9) through the light sludge collection pipe (7). The upper end of the hexagonal spherical segment (18) is provided with an agglomeration hydrocyclone overflow pipe (21). The agglomeration hydrocyclone inlet pipe (17) tangentially arranged on the side wall of the hexagonal spherical segment (18) is connected to the bottom of the central pipe (11). Each inner wall surface of the hexagonal spherical segment (18) is provided with an inclined baffle (22). The included angle between each baffle (22) and the corresponding inner wall surface is the same. The height of each baffle (22) is the same as the height of the hexagonal spherical segment (18). The agglomeration hydrocyclone inlet pipe (17), the agglomeration hydrocyclone underflow pipe (20), and the agglomeration hydrocyclone overflow pipe (21) are all hexagonal structures.

4. A low-pressure driven cyclone-enhanced high-efficiency anaerobic reactor according to claim 2 or 3, characterized in that: The inlet end of the central tube (11) has a funnel-shaped structure.

5. The low-pressure driven cyclone-enhanced high-efficiency anaerobic reactor according to claim 4, characterized in that: The lower part of the inner wall of the cylindrical section (10) of the reactor is a spiral wall.

6. The low-pressure driven cyclone-enhanced high-efficiency anaerobic reactor according to claim 5, characterized in that: The device also includes an external hydrocyclone, which includes an external hydrocyclone cylindrical section (26) and an external hydrocyclone conical section (27) that are welded and fixed at the top and bottom. The external hydrocyclone inlet pipe (25) tangentially arranged on the side wall of the external hydrocyclone cylindrical section (26) is connected to the lower part of the reactor conical section (9) through a drainage pipe (30). The external hydrocyclone overflow pipe (29) at the upper end of the external hydrocyclone cylindrical section (26) is connected to the reactor conical section (9) and the reactor cylindrical section (10) through a return pipe (31). The lower end of the external hydrocyclone conical section (27) is provided with an external hydrocyclone underflow pipe (28).

7. The low-pressure driven cyclone-enhanced high-efficiency anaerobic reactor according to claim 6, characterized in that: The number of reactor inlet pipes (5) is at least one.

8. The low-pressure driven cyclone-enhanced high-efficiency anaerobic reactor according to claim 7, characterized in that: The outlet of the central tube (11) is provided with a cleaning port.

9. A method for operating the low-pressure driven cyclone-enhanced high-efficiency anaerobic reactor according to any one of claims 1-8, characterized in that: The method includes the following steps: S1: Wastewater in the original wastewater treatment system is injected tangentially into the conical section (9) of the reactor through the reactor inlet pipe (5). Due to the tangential water inlet, the wastewater generates a high-speed swirling flow along the side wall of the conical section (9) of the reactor and rises axially. S2: Under the shearing force of high-speed swirling, heavy granular sludge is thrown to the inner wall and retained, while light sludge and suspended solids are sheared and dispersed and aggregate towards the center. At the same time, the sludge and sewage undergo anaerobic reaction to produce biogas (12). S3: Under the combined impetus of biogas (12) and high-speed swirling, heavy granular sludge, light sludge and suspended solids swirl and rise together. The heavy granular sludge continues to move along the side wall, while the light sludge and suspended solids are in the central area. S4: When the water flows into the spiral wall of the cylindrical section (10) of the reactor, the mixed liquid rises along the spiral wall. The spiral wall compensates for and maintains the swirling flow field, so that the liquid flow still maintains a strong tangential velocity. At the same time, the spiral wall generates local eddies during the flow guidance process, which drives the sludge particles to rotate and entangle, promotes the aggregation and granulation of flocculent sludge, and the sludge attached to the wall also falls off due to shearing and participates in the circulation mixing. S5: When the water flow reaches the top of the cylindrical section (10) of the reactor, the three-phase separator (13) begins gas-liquid-solid separation. Biogas (12) enters the biogas collection pipe (15) through the gas cap and is discharged. Clarified water is introduced into the effluent weir (14) through the guide tube. Due to the continuous swirling effect, the heavy granular sludge settles back along the inclined baffle of the three-phase separator (13) and is retained on the side wall of the reactor. The light sludge and suspended solids are concentrated in the central area and are pressed into the central pipe (11) by the low pressure zone in the center of the swirling flow and discharged to the agglomeration cyclone. S6: Agglomeration hydrocyclones are used to optimize sludge communities and separate light sludge. S7: When the system treats wastewater containing large suspended solid particles, the sludge mixture in the conical section (9) of the reactor is pumped into the external hydrocyclone. The gravel is discharged through the underflow pipe (28) of the external hydrocyclone, and the sludge is returned to the junction of the cylindrical section (10) and the conical section (9) of the reactor through the overflow pipe (29) of the external hydrocyclone.

10. The operating method of a low-pressure driven cyclone-enhanced high-efficiency anaerobic reactor according to claim 9, characterized in that: S6 includes the following steps: S601: The return sludge mixture enters the inlet pipe (17) of the agglomeration hydrocyclone from the central pipe (11). The gravitational potential energy is converted into tangential kinetic energy by the tangential flow, causing the sludge mixture to rotate in the agglomeration hydrocyclone to form a rotating flow. S602: The sludge mixture is guided and disturbed by the inclined baffle (22) in the hexagonal section (18), generating a strong and uniform rotating flow. At the inner corner of the hexagon and the tail edge of the baffle, the magnitude and direction of the water flow velocity will differ from the adjacent water flow, thus forming a velocity gradient in the local area. S603: Small-scale eddies are formed inside the hydrocyclone. Due to the interaction of the rotating flow and the small-scale eddies, the flocculent sludge collides and entangles with each other. The sludge will rotate in the hydrocyclone, thereby inducing micro-interface oscillation, which together promotes the further aggregation of flocculent sludge. At the same time, the high shear force in the small-scale eddies causes some small-diameter suspended solids to desorb from the sludge surface. S604: In the overall swirling field of the hydrocyclone, due to the centrifugal force generated by the tangential kinetic energy, the sludge with high density and good agglomeration effect gathers towards the wall and enters the underflow pipe (20) of the agglomeration hydrocyclone with the outer swirling flow. The loose or poor-performing sludge and small-diameter suspended solids gather towards the center and rise with the inner swirling flow, and are discharged through the overflow pipe (21) of the agglomeration hydrocyclone, thereby realizing the optimization of the sludge group and the separation of light sludge.

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