A variable density self-circulating sludge granulation device

Abstract

This invention relates to the field of wastewater treatment technology and provides a variable-density self-circulating sludge granulation device, comprising: an anoxic tank, an aerobic tank, and a sedimentation tank arranged along a water flow path; a water acceleration device disposed within the anoxic tank; a return main pipe, with an inlet end having a sludge return branch pipe extending into the sedimentation tank and / or a nitrified liquid return branch pipe extending into the aerobic tank, and an outlet end having a first pipe section extending into the anoxic tank and located within a throat; the outlet end of the return main pipe also having a second pipe section extending into the anoxic tank and located outside the throat; and an aeration pipe, one end of which extends into the second pipe section, and the other end being adapted to be connected to an air source, through which gas is introduced into the second pipe section. This device utilizes the negative pressure generated by the influent jet and the air lift effect generated by the aeration pipe for dual diversion, allowing nitrified liquid and / or sludge to return to the anoxic tank, which is energy-saving and environmentally friendly without increasing the burden of system maintenance.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and specifically to a variable density self-circulating sludge granulation device. Background Technology

[0002] Existing aerobic reactors mainly consist of an anoxic zone, an aerobic zone, and a sedimentation zone arranged sequentially along the wastewater flow path. Raw wastewater enters the anoxic zone and mixes with internal microorganisms for anoxic reactions. The wastewater then enters the aerobic zone for further aerobic reactions to remove pollutants. Finally, the wastewater enters the sedimentation zone for sedimentation and separation. The downstream aerobic zone contains a large amount of nitrifying liquid, while the sedimentation zone contains a large amount of sludge. Current technologies typically use pumps and pipelines to recirculate the nitrifying liquid or sludge to improve water treatment efficiency. However, this design is not energy-efficient or environmentally friendly and increases the burden of system maintenance. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is that the traditional aerobic reaction device uses a pump body and pipeline to return nitrification liquid or sludge. However, such a design is not conducive to energy saving and environmental protection and will increase the burden of system maintenance. Therefore, a variable density self-circulating sludge granulation device is provided.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0005] This invention provides a variable-density self-circulating sludge granulation device, comprising: an anoxic tank, an aerobic tank, and a sedimentation tank arranged along a water flow path; a water acceleration device disposed within the anoxic tank, including a throat and at least one stage of spray pipe, the throat covering the top of the spray pipe, external water being accelerated by the spray pipe before entering the throat, and the water then being released from the top of the throat into the anoxic tank; and a return main pipe, the inlet end of which is provided with a sludge return branch pipe extending into the sedimentation tank and / or a nitrate return branch pipe extending into the aerobic tank. The return branch pipe has a first pipe section extending into the anoxic tank and located inside the throat at its outlet end. The first pipe section uses the negative pressure inside the throat to introduce sludge and / or nitrified liquid into the throat. The return branch pipe also has a second pipe section extending into the anoxic tank and located outside the throat at its outlet end. A vent pipe has one end extending into the second pipe section and the other end adapted to be connected to a gas source. The vent pipe introduces gas into the second pipe section and uses air lifting to introduce sludge and / or nitrified liquid into the anoxic tank.

[0006] Furthermore, the variable density self-circulating sludge granulation device also includes a lightweight sludge hopper; the lightweight sludge hopper is located at the end of the sludge return branch pipe away from the return main pipe, and the opening of the lightweight sludge hopper faces upward.

[0007] Furthermore, the variable density self-circulating sludge granulation device also includes an aerobic inlet water distribution tank, which is located between the aerobic tank and the anoxic tank. The water in the anoxic tank first enters the aerobic inlet water distribution tank and then enters the aerobic tank. The second pipe section is located in the aerobic inlet water distribution tank.

[0008] Furthermore, the variable density self-circulating sludge granulation device also includes a degassing channel; the degassing channel is located between the aerobic tank and the sedimentation tank, and the cross-sectional area of ​​the downstream channel is larger than that of the upstream channel. The water in the aerobic tank is degassed in the degassing channel and then enters the sedimentation tank; the nitrification liquid return branch pipe is located in the degassing channel.

[0009] Furthermore, the inlet of the nitrated liquid return branch pipe faces downward and is located in the downstream channel of the degassing channel.

[0010] Furthermore, a first return water inlet is provided between the degassing channel and the aerobic tank. A portion of the water in the degassing channel enters the downstream sedimentation tank, while another portion of the water flows back to the upstream aerobic tank through the first return water inlet.

[0011] Furthermore, an aeration device is provided in the aerobic tank, the aeration device including an aerator and an accelerator; the aerator is located at the bottom of the aerobic tank and is used to provide the gas required for the aerobic reaction; the accelerator includes a premixing hood and a speed-maintaining component; the premixing hood covers the air outlet of the aerator, and the space between the premixing hood and the aerator forms a first premixing zone; a gap is left between the premixing hood and the aerator to form a second return water inlet, the second return water inlet connecting the interior and exterior spaces of the first premixing zone; wherein, the flow area of ​​the release port of the premixing hood is smaller than the flow area of ​​the inlet of the premixing hood, so as to increase the pressure in the first premixing zone under aeration; one end of the speed-maintaining component is connected to the release port of the premixing hood, and the other end extends away from the premixing hood.

[0012] Furthermore, the variable density self-circulating sludge granulation device also includes a partition plate disposed in the lower half of the aerobic tank. The partition plate divides the lower half of the aerobic tank into multiple aeration zones, and the aeration device is disposed in the aeration zone. The space between two adjacent aeration zones forms an internal return channel. A gap is left between the bottom of the partition plate and the bottom of the aerobic tank to connect the aeration zone and the internal return channel. The water flow direction in the internal return channel is opposite to the water flow direction in the aeration zone. A guide cone is provided at the bottom of the internal return channel to guide the water in the internal return channel back to the aeration zone.

[0013] Furthermore, a sludge filter layer is formed in the sedimentation tank, with a nitrification filter layer at the bottom and a denitrification filter layer at the top. While the sludge filter layer filters the water, the nitrification filter layer removes ammonia nitrogen from the water, and the denitrification filter layer removes total nitrogen and COD from the water.

[0014] Furthermore, the variable density self-circulating sludge granulation device also includes a sludge discharge pipe, one end of which is connected to the lightweight collection hopper, and the other end extends to the outside of the aerobic tank.

[0015] Furthermore, the anoxic tank contains, in sequence, a mixing zone, an upflow anoxic zone, an anaerobic backflow channel, and an upflow anaerobic reaction zone along the water flow path. Both the nozzle and the throat are located within the mixing zone, with a third return inlet between them. A portion of the water in the mixing zone flows back into the throat via this third return inlet. Another portion of the water in the mixing zone flows out from the bottom and into the upflow anoxic zone. Within the upflow anoxic zone, the water flows upward to the top and then enters the anaerobic guide channel. The water in the anaerobic guide channel flows downward to the bottom and then enters the upflow anaerobic reaction zone. Finally, the water in the upflow anaerobic reaction zone flows upward to the top and then enters the aerobic inlet distribution tank.

[0016] Furthermore, the variable density self-circulating sludge granulation device also includes an anaerobic effluent weir and an anaerobic water distribution pipe; the anaerobic effluent weir is located at the top of the upflow anaerobic reaction zone, and the water enters the anaerobic effluent weir and is then transported to the aerobic inlet water distribution tank; the inlet end of the anaerobic water distribution pipe is connected to the anaerobic backflow channel, and the outlet end of the anaerobic water distribution pipe is set parallel to the bottom of the upflow anaerobic reaction zone so that the inlet water is evenly distributed at the bottom of the upflow anaerobic reaction zone.

[0017] Furthermore, the variable density self-circulating sludge granulation device also includes an anoxic return pipe, one end of which extends into the throat pipe and the other end is located in the upflow anaerobic reaction zone; the opening of the anoxic return pipe faces upward and extends into the upper half of the upflow anaerobic reaction zone, so that the anaerobic wastewater in the upflow anaerobic reaction zone is returned to the mixing zone.

[0018] Furthermore, the anoxic tank, aerobic tank, and sedimentation tank are integrated into one tank body, and the different areas divided within the tank body form the anoxic tank, aerobic tank, and sedimentation tank; or one or more of the anoxic tank, aerobic tank, and sedimentation tank are each composed of a separate tank body.

[0019] Furthermore, the variable density self-circulating sludge granulation device also includes a lifting agitator, which is located in the mixing zone to accelerate the rise of water in the throat.

[0020] The technical solution of this invention has the following advantages:

[0021] The variable density self-circulating sludge granulation device provided by this invention utilizes the negative pressure generated by the influent jet and the air lift generated by the aeration pipe for dual diversion, allowing nitrified liquid and / or sludge to return to the anoxic tank. Compared to using a pump and pipeline for nitrified liquid and / or sludge return, this method is energy-saving and environmentally friendly, and does not increase the burden of system maintenance. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a top view of the variable density self-circulating sludge granulation device in an embodiment of the present invention;

[0024] Figure 2 For along Figure 1 A cross-sectional view along the AA direction;

[0025] Figure 3 This is a partial enlarged schematic diagram of the aerobic tank in the variable density self-circulating sludge granulation device in an embodiment of the present invention.

[0026] Figure 4 For along Figure 1 A cross-sectional view along the BB direction;

[0027] Figure 5 This is a schematic diagram of an aeration device according to one embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram of an aeration device in another embodiment of the present invention;

[0029] Figure 7 This is a schematic diagram of an aeration device in another embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of an aeration device in another embodiment of the present invention;

[0031] Figure 9 This is a schematic diagram of the aerator layout in one embodiment of the present invention;

[0032] Figure 10 This is a schematic diagram of the lifting agitator in a variable density self-circulating sludge granulation device according to one embodiment of the present invention;

[0033] Figure 11 This is a schematic diagram of the lifting agitator in a variable density self-circulating sludge granulation device according to another embodiment of the present invention.

[0034] Figure 12 This is a schematic diagram of the lifting agitator in a variable density self-circulating sludge granulation device according to another embodiment of the present invention.

[0035] Figure 13 This is a schematic diagram of the lifting agitator in a variable density self-circulating sludge granulation device according to another embodiment of the present invention.

[0036] Figure 14 This is a schematic diagram of the lifting agitator in a variable density self-circulating sludge granulation device according to another embodiment of the present invention.

[0037] Figure 15 This is a schematic diagram of the lifting agitator in a variable density self-circulating sludge granulation device according to another embodiment of the present invention.

[0038] Figure 16 This is a schematic diagram of the lifting agitator in a variable density self-circulating sludge granulation device according to another embodiment of the present invention.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. Anoxic tank; 2. Aerobic tank; 3. Sedimentation tank; 4. Main return pipe; 5. Sludge return branch pipe; 6. Nitrified liquor return branch pipe; 7. First pipe section; 8. Second pipe section; 9. Ventilation pipe; 10. Light sludge hopper; 11. Aerobic inlet water distribution tank; 12. Deaeration channel; 13. First return water inlet; 14. Aerator; 15. Premixing hood; 16. Speed-maintaining component; 17. First premixing zone; 18. Second return water inlet; 19. Baffle plate; 20. Internal return channel; 21. Aeration zone; 22. Guide cone; 23. Sludge filter layer; 4. Denitrification filter layer; 25. Nitrification filter layer; 26. Sludge discharge pipe; 27. Throat pipe; 28. Spray pipe; 29. ​​Third return water inlet; 30. Mixing zone; 31. Inclined tube separator; 32. Effluent trough; 33. Upflow anoxic zone; 34. Anaerobic guide channel; 35. Upflow anaerobic reaction zone; 36. Anaerobic effluent weir; 37. Anaerobic water distribution pipe; 38. Anoxic return pipe; 39. Drain pipe; 40. Regulator; 41. Baffle; 42. Second premixing zone; 43. Diversion port; 44. Toothed inlet; 45. Lifting agitator. Detailed Implementation

[0041] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0045] like Figure 1 , Figure 2 As shown, the present invention provides a variable density self-circulating sludge granulation device, comprising: an anoxic tank 1, an aerobic tank 2, and a sedimentation tank 3 arranged along a water flow path; for example, the anoxic tank 1, aerobic tank 2, and sedimentation tank 3 can be integrated into one tank body, with different areas divided within the tank body forming the anoxic tank 1, aerobic tank 2, and sedimentation tank 3. Alternatively, one or more of the anoxic tank 1, aerobic tank 2, and sedimentation tank 3 can be composed of separate tank bodies; for example, the anoxic tank 1 can be composed of a separate tank body, while the aerobic tank 2 and sedimentation tank 3 can be integrated into another tank body; or, for yet another example, the anoxic tank 1, aerobic tank 2, and sedimentation tank 3 can all be composed of separate tank bodies.

[0046] In some scenarios, there may be more than one anoxic tank 1, aerobic tank 2, and sedimentation tank 3; they can be multiple paired with multiple tanks, or one paired with multiple tanks. For example, in some scenarios, there may be one anoxic tank 1 corresponding to multiple aerobic tanks 2 and sedimentation tanks 3. Moreover, as long as the upstream and downstream relationships of anoxic tank 1, aerobic tank 2, and sedimentation tank 3 remain unchanged, their positional relationships can be designed according to needs. For example, from left to right, they can be anoxic tank 1, aerobic tank 2, and sedimentation tank 3. Or, from left to right, they can be sedimentation tank 3, aerobic tank 2, anoxic tank 1, aerobic tank 2, and sedimentation tank 3, and so on.

[0047] Among them, the bodies of the anoxic tank 1, aerobic tank 2 and sedimentation tank 3 can be made of steel or concrete, and the cross-sectional shape of each tank can be circular, rectangular or other polygonal, etc.

[0048] like Figure 1 As shown, in order to more clearly illustrate the inventive concept of this application, the following embodiments take the anoxic tank 1, aerobic tank 2 and sedimentation tank 3 as an example of being in the same tank body, and the sedimentation tank 3, aerobic tank 2, anoxic tank 1, aerobic tank 2 and sedimentation tank 3 are arranged sequentially along the first direction (left and right direction) in the tank body.

[0049] A water acceleration device, installed inside the anoxic tank 1, includes a throat 27 and at least one stage of nozzles 28. The nozzles 28 can be configured with one or more stages to accelerate the water. The throat 27 covers the top of the nozzles 28. External water is accelerated by the nozzles 28 and enters the throat 27, then released from the top of the throat 27 into the anoxic tank 1. A return main pipe 4 has a sludge return branch pipe 5 extending into the sedimentation tank 3 and / or a nitrified liquid return branch pipe 6 extending into the aerobic tank 2 at its inlet end. The return main pipe 4 has a first pipe section 7 extending into the anoxic tank 1 and located inside the throat 27. The first pipe section 7 uses the negative pressure inside the throat 27 to introduce sludge and / or nitrified liquid into the throat 27. The return main pipe 4 also has a second pipe section 8 extending into the anoxic tank 1 and located outside the throat 27 at its outlet end.

[0050] When the volume of water to be treated is large, multiple water acceleration devices can be installed in the anoxic tank 1 at the same time, and water can be introduced into the multiple water acceleration devices at the same time to increase the water intake.

[0051] A vent pipe 9 extends one end into the second pipe section 8, and the other end is adapted to connect to a gas source. Gas is introduced into the second pipe section 8 through the vent pipe 9, and sludge and / or nitrified liquid are introduced into the anoxic tank 1 using airlift. For example, the air inlet of the vent pipe 9 is located at its top, extending outside the anoxic tank 1 and connected to an air pump or other gas source device. The air outlet of the vent pipe 9 is located at its bottom, where the gas is released. A concentration difference is created between the outlet and inlet of the return main pipe 4, and the fluid at the inlet of the return main pipe 4 is then diverted to the outlet for release. For example, the nitrified liquid return branch pipe 6 and the sludge return branch pipe 5 can be arranged simultaneously, or only one of them can be arranged.

[0052] The variable density self-circulating sludge granulation device provided by this invention utilizes the negative pressure generated by the influent jet and the air lift generated by the aeration pipe 9 for dual diversion, allowing the nitrified liquid and / or sludge to return to the anoxic tank 1. Compared to using a pump and pipeline for nitrified liquid and / or sludge return, this method is energy-saving and environmentally friendly, and does not increase the burden of system maintenance.

[0053] Under normal circumstances, due to the sludge return, gravity, and influent flow, a sludge filter layer 23 is formed in the sedimentation tank 3. The lower layer of the sludge filter layer 23 is the nitrification filter layer 25, and the upper layer of the sludge filter layer 23 is the denitrification filter layer 24. While the sludge filter layer 23 filters the suspended solids in the water, the nitrification filter layer 25 removes ammonia nitrogen from the water, and the denitrification filter layer 24 removes total nitrogen and COD (Chemical Oxygen Demand) from the water. The variable density self-circulating sludge granulation device also includes a light sludge hopper 10. The light sludge hopper 10 is located at the end of the sludge return branch pipe 5 away from the return main pipe 4, and the opening of the light sludge hopper 10 is set upward. The opening of the light sludge hopper 10 can be flush with the upper denitrification filter layer 24, so that the sludge of the denitrification filter layer 24 can be returned to the anoxic tank 1 for denitrification reaction, thereby removing COD and total nitrogen from the water.

[0054] The variable density self-circulating sludge granulation device also includes an aerobic inlet water distribution tank 11, which is located between the aerobic tank 2 and the anoxic tank 1. The water in the anoxic tank 1 first enters the aerobic inlet water distribution tank 11 and then enters the aerobic tank 2. The second pipe section 8 is located in the aerobic inlet water distribution tank 11. The top of the second pipe section 8 is bent and extends into the upper half of the anoxic tank 1. One end of the vent pipe 9 extends into the aerobic inlet water distribution tank 11 and is inserted into the second pipe section 8. The other end extends to the outside of the aerobic inlet water distribution tank 11 and can be connected to the air source.

[0055] The variable density self-circulating sludge granulation device also includes a degassing channel 12. The degassing channel 12 is located between the aerobic tank 2 and the sedimentation tank 3. The downstream section of the degassing channel 12 has a larger cross-sectional area than the upstream section. Water in the aerobic tank 2 is degassed within the degassing channel 12 before entering the sedimentation tank 3. A nitrification liquid return branch pipe 6 is located within the degassing channel 12. For example, the outlet of the nitrification liquid return branch pipe 6 can be downward-facing and located within the downstream section of the degassing channel 12. Due to the enlarged cross-section of the downstream section of the degassing channel 12, the water flow velocity is low, allowing time for sludge and water to separate, and the low velocity ensures more thorough degassing.

[0056] A first return water inlet 13 is provided between the deaeration channel 12 and the aerobic tank 2. For example, the first return water inlet 13 can be located at the bottom of the deaeration channel 12. Part of the water in the deaeration channel 12 enters the downstream sedimentation tank 3, and the other part of the water flows back to the upstream aerobic tank 2 through the first return water inlet 13. A guide plate can be installed on the inner wall of the deaeration channel 12, inclined towards the location of the first return water inlet 13. Under the guidance of the guide plate, the water preferentially flows back to the aerobic tank 2, and then the remaining water enters the downstream sedimentation tank 3. Moreover, since the inlet of the deaeration channel 12 is at the top of the aerobic tank 2, the sludge can be settled in the aerobic tank 2 by relying on the height.

[0057] The middle part of the degassing channel 12 can be tilted towards the sedimentation tank 3 to block the sludge in the aerobic tank 2 from moving upward, so that the sludge in the aerobic tank 2 can enter the aeration zone 21 more easily and reduce the amount of sludge entering the degassing channel 12.

[0058] like Figure 3As shown, an aeration device is installed in the aerobic tank 2, which includes an aerator 14 and an accelerator. The aerator 14 is located at the bottom of the aerobic tank 2 and is used to provide the gas required for the aerobic reaction. The accelerator includes a premixing hood 15 and a speed-maintaining component 16. The premixing hood 15 covers the air outlet of the aerator 14, and the space between the premixing hood 15 and the aerator 14 forms a first premixing zone 17. A gap is left between the premixing hood 15 and the aerator 14 to form a second return water inlet 18, which connects the interior and exterior spaces of the first premixing zone 17. The flow area of ​​the release port of the premixing hood 15 is smaller than the flow area of ​​the inlet of the premixing hood 15 to increase the pressure in the first premixing zone 17 under aeration conditions. One end of the speed-maintaining component 16 is connected to the release port of the premixing hood 15, and the other end extends away from the premixing hood 15. For example, the premixing hood 15 can be a frustum-shaped structure with open ends at both the top and bottom, the larger opening at the bottom and the smaller opening at the top, with the smaller opening serving as the release port. Alternatively, the premixing hood 15 can also be a frustum-shaped structure with open ends at both the top and bottom, the larger opening at the bottom and the smaller opening at the top, with the smaller opening serving as the release port. The premixing hood 15 can be welded to the side wall of the aerobic tank 2 by installing connecting rods on its side wall; or it can be integrated with the air pipe support of the aerator 14 and fixed to the air pipe support of the aerator 14. The velocity retainer 16 can be a round tube or a square tube, depending on the requirements. Because the velocity retainer 16 increases the height of the release port of the premixing hood 15, the flow velocity of the air-water mixture outside the premixing hood 15 is lower, resulting in a larger velocity difference between the air-water mixture outside the first premixing zone 17 and the premixing hood 15. Therefore, the pressure difference is greater, resulting in a better flow diversion effect compared to when the velocity retainer 16 is not present.

[0059] In operation, aerator 14 releases air into the first premixing zone 17. The rapid rise of the bubbles draws water from outside the first premixing zone 17 into the first premixing zone 17 via the second return port 18. Additionally, the narrowing of the release port directly above the premixing hood 15 increases the pressure in the first premixing zone 17, further mixing the bubbles with the water returning through the second return port 18. The increased pressure also improves the dissolution of the gas into the water. The resulting air-water mixture is then sprayed out through the release port and rises to the aerobic area outside the first premixing zone 17. The speed-maintaining component 16 prolongs the high-speed water movement time, delaying the release. This design allows the aeration device to increase dissolved oxygen concentration through reflux, mixing, and pressurized gas dissolution, resulting in higher efficiency and greater energy savings under the same aeration conditions. The variable density self-circulating sludge granulation device also includes a partition plate 19, which is installed in the lower half of the aerobic tank 2. The partition plate 19 divides the lower half of the aerobic tank 2 into multiple aeration zones 21, and aeration devices are installed in the aeration zones 21. The space between two adjacent aeration zones 21 forms an internal return channel 20. A gap is left between the bottom of the partition plate 19 and the bottom of the aerobic tank 2, connecting the aeration zones 21 and the internal return channel 20. The water flow direction in the internal return channel 20 is opposite to that in the aeration zones 21. In use, the gas action of the aerator 14 can be used to accelerate water intake, resulting in a larger volume of return water, thereby accelerating the circulation and return between the internal return channel 20 and the aeration zones 21, and enabling rapid water mixing. Moreover, under the action of aeration, the water flow in the aeration zone 21 rises rapidly, and the heavy sludge will descend from the inner return channel 20 and then participate in the aeration upward process again, which makes the sludge particle formation efficiency faster. In addition, through this high-speed rise and fall, air and water scrubbing makes the granular sludge more stable and the granular sludge ball diameter ratio better.

[0060] The bottom of the internal return channel 20 is equipped with a guide cone 22 to guide the water in the internal return channel 20 back to the aeration zone 21. This design can prevent sludge accumulation in the internal return channel 20 and facilitate the guidance of airlift flow.

[0061] like Figure 5 As shown, in one embodiment, the release port of the premixed hood 15 may not be equipped with a speed-keeping component 16.

[0062] like Figure 6As shown, the aeration device also includes a rectifier 40, which covers the release port of the premixing hood 15. The end of the rectifier 40 away from the premixing hood 15 is sealed, and the inner diameter of the rectifier 40 gradually decreases in the direction away from the premixing hood 15. The space between the rectifier 40 and the premixing hood 15 forms a second premixing zone 42. A gap is left between the rectifier 40 and the premixing hood 15 to form a diversion port 43, which connects the second premixing zone 42 to the space outside the second premixing zone 42. The rectifier 40 can be welded to the side wall of the aeration zone 21 by means of connecting rods provided on the side wall. For example, the rectifier 40 can be a conical structure with the cone apex at the top. As another example, the premixing hood 15 can also be a prismatic structure with the smaller top surface at the top. The shape of the rectifier 40 is adapted to the shape of the premixing hood 15. For example, when the premixing hood 15 is a frustum-shaped structure, the rectifier 40 can be a conical structure. For example, when the premixing hood 15 has a frustum-shaped structure, the rectifier hood 40 can have a prism-shaped structure. In use, the air-water mixture in the first premixing zone 17 enters the second premixing zone 42 through the release port of the premixing hood 15. The air-water mixture in the second premixing zone 42 flows out through the branch port 43 and splits into a first branch and a second branch. The air-water mixture in the first branch moves towards the second return port 18, thus forming a circulation. The air-water mixture in the second branch flows downstream over the rectifier hood 40. Furthermore, since the sidewall of the rectifier hood 40 is inclined, it forms a slope. A portion of the air-water mixture slides down the slope (due to the velocity difference created by the acceleration of the edge fluid), colliding and mixing with the rapidly rising air-water mixture in the second branch, thereby improving the mixing effect. With this configuration, the aeration zone 21 has recirculation, mixing, and pressurized dissolved gas, increasing the dissolved oxygen concentration. Under the same aeration conditions, efficiency is improved, resulting in greater energy savings.

[0063] like Figure 7 As shown, in one embodiment, the fairing 40 may also be disposed over the end of the speed-maintaining member 16 away from the premixing cover 15.

[0064] like Figure 9 As shown, the edge of the shroud 40 can be provided with several toothed orifices 44, which are distributed circumferentially along the shroud 40. This arrangement has two advantages: first, the toothed orifices 44 enhance the mixing effect because the flow velocities in the concave and convex areas of the orifices differ, increasing the turbulent mixing effect; second, it has the function of cutting bubbles, breaking large bubbles into smaller ones, increasing the contact area with water, and thus increasing dissolved oxygen. Furthermore, the horizontal and downward backflow of the air-water mixture further enhances the mixing effect, and the downward flow of the mixture increases the mixing distance, extending the effective contact time and preventing it from rising directly to the liquid surface. This arrangement increases the mixing distance, prolongs the reaction time, and improves the dissolved oxygen concentration; under the same aeration conditions, it increases efficiency and is more energy-efficient.

[0065] like Figure 8 As shown, the aeration device also includes a baffle 41, which is disposed inside the shroud 40, with the baffle 41 facing the outlet of the retaining element 16. During use, the gas-water mixture released from the outlet at the top of the retaining element 16 impacts the baffle 41 and then diffuses outwards. This arrangement prevents air from accumulating at the top of the shroud 40, thus preventing bubble aggregation and ensuring smooth gas release into the water, thereby improving the gas-water mixing effect.

[0066] The variable density self-circulating sludge granulation device also includes a sludge discharge pipe 26, one end of which is connected to the lightweight sludge collection hopper, and the other end extends to the outside of the aerobic tank 2. For example, a control valve can be installed on the sludge discharge pipe 26. During water treatment, the control valve is closed; when the spray pipe 28 stops supplying water and the aeration pipe 9 stops supplying air, the control valve is opened, and the sludge in the lightweight sludge hopper 10 is discharged through the sludge discharge pipe 26.

[0067] Among them, such as Figure 1 , Figure 4 As shown, along the second direction (up and down direction), the anoxic tank 1 contains, in sequence, a mixing zone 30, an upflow anoxic zone 33, an anaerobic guide channel 34, and an upflow anaerobic reaction zone 35 along the water flow path. The upflow anoxic zone 33, the anaerobic guide channel 34, and the upflow anaerobic reaction zone 35 are symmetrically distributed on both sides of the mixing zone 30 along the second direction.

[0068] Both nozzle 28 and throat 27 are located within mixing zone 30. A third return inlet 29 is provided between nozzle 28 and throat 27. A portion of the water in mixing zone 30 flows back into throat 27 through the third return inlet 29. Another portion of the water in mixing zone 30 flows out from the bottom and enters upflow anoxic zone 33. The water in upflow anoxic zone 33 flows upward to the top and then enters anaerobic guide channel 34. The water in anaerobic guide channel 34 flows downward to the bottom and then enters upflow anaerobic reaction zone 35. The water in upflow anaerobic reaction zone 35 flows upward to the top and then enters aerobic inlet water distribution tank 11. In this design, guide plates are installed on the inner wall of the mixing zone 30, tilted towards the location of the third return water inlet 29. Guided by these plates, water preferentially flows back into the mixing zone 30, and the remaining water enters the downstream upflow anoxic zone 33. This also helps to retain sludge within the mixing zone 30 as much as possible. This arrangement ensures that the water in both the upflow anoxic zone 33 and the upflow anaerobic reaction zone 35 flows upwards, allowing microorganisms to rise hydraulically and remain suspended, facilitating nutrient acquisition and resulting in a more thorough reaction.

[0069] The variable density self-circulating sludge granulation device also includes an anaerobic effluent weir 36 and an anaerobic water distribution pipe 37. The anaerobic effluent weir 36 is located at the top of the upflow anaerobic reaction zone 35 and connects the upflow anaerobic reaction zone 35 with the aerobic inlet water distribution tank 11. After entering the anaerobic effluent weir 36, the water is then transported to the aerobic inlet water distribution tank 11. The inlet end of the anaerobic water distribution pipe 37 is connected to the anaerobic guide channel 34, and the outlet end of the anaerobic water distribution pipe 37 is set parallel to the bottom of the upflow anaerobic reaction zone 35. Spray holes are set on the pipe section corresponding to the outlet end of the anaerobic water distribution pipe 37, and the spray holes spray water towards the bottom of the upflow anaerobic reaction zone 35 so that the inlet water is evenly distributed at the bottom of the upflow anaerobic reaction zone 35.

[0070] The variable-density self-circulating sludge granulation device also includes an anoxic return pipe 38, one end of which extends into the throat pipe 27, and the other end is located in the upflow anaerobic reaction zone 35. The opening of the anoxic return pipe 38 faces upward and extends into the upper half of the upflow anaerobic reaction zone 35, so that the anaerobic wastewater in the upflow anaerobic reaction zone 35 is returned to the mixing zone 30. For example, the opening of the anoxic return pipe 38 can also be a funnel-shaped structure to increase the inflow rate during return. This configuration increases the water volume in the mixing zone 30, increases the upward flow velocity, suspends the sludge, and replenishes and inoculates the sludge in the mixing zone 30 by returning a portion of the anaerobic sludge.

[0071] During operation, before the raw water enters the mixing zone 30, it is accelerated by spraying from nozzles and the mixed return water. Within the mixing zone 30, a circulating mixing reaction occurs, with the water flowing upwards from the center and downwards from the sides. This section includes anaerobic wastewater return from the upflow anaerobic reaction zone 35, sludge return from the sedimentation tank 3, and nitrified liquid return from the degassing channel 12. This return water mixes with the raw water and undergoes denitrification to remove COD and total nitrogen. The water in the mixing zone 30 enters the bottom of the upflow anoxic zone 33, rises, and enters the anaerobic guide channel 34, then enters the upflow anaerobic reaction zone 35 (named the upflow anaerobic reaction zone 35 because oxygen is gradually consumed in this section). The bottom of the upflow anaerobic reaction zone 35 has a distribution pipe to evenly distribute the water before it rises. The upper part of the upflow anaerobic reaction zone 35 has an anaerobic effluent weir 36, which feeds water into the aerobic inlet and distribution tanks 11 on both sides. Down from the anaerobic effluent weir 36 is an anoxic return pipe 38, which returns the water to the mixing zone 30.

[0072] The sedimentation tank 3 can also be equipped with an inclined tube separator 31 to further separate and settle small suspended solids that have escaped. A effluent trough 32 is located downstream of the inclined tube separator 31, and an effluent pipe is connected to the effluent trough 32. Clean water enters the effluent trough 32 and is discharged from the effluent pipe. A drain pipe 39 can also be installed at the bottom of the sedimentation tank 3 to drain the sludge and water from the sedimentation tank 3.

[0073] like Figure 10As shown, in one embodiment, the variable density self-circulating sludge granulation device further includes a lifting agitator 45. The base of the lifting agitator 45 can be installed on top of the mixing zone 30, and the connecting rod and the spiral fan blades of the lifting agitator 45 extend into the throat 27. In use, the lifting agitator 45 can promote the rise of water in the throat 27. For example, the lifting agitator 45 can be frequency-controlled so that the speed of the spiral fan blades can be adjusted, and the flow rate of the rising water can also be adjusted, thus the amount of water returning will also change with the speed. The lifting agitator 45 can be used alone or in conjunction with jetting and airlift.

[0074] like Figure 11 As shown, in one embodiment, the bottom of the mixing zone 30 uses pressurized water intake, which is accelerated by jets after intake. Multiple acceleration devices are used in the rising section for flow diversion. In addition to the jet acceleration, an upper-level agitator 45 provides upward flow assistance. The rotation speed of the spiral fan blades can change the force and flow rate of the diversion. The throat 27 has two or more layers of diversion, which can recirculate and mix the water that needs to be returned from the anoxic zone, aerobic zone, and sedimentation zone.

[0075] like Figure 12 As shown, in one embodiment, gravity inlet is used at the bottom of mixing zone 30. Due to the increased upward flow velocity of the lifting agitator 45, the required backflow during the ascent can be accelerated by a variable diameter flow. All upward flow is through channel spiral fan blades, and the number of spiral fan blade layers can be calculated to be two or more layers. The rotation speed of the spiral fan blades can change the inflow force and flow rate. The throat 27 has two or more layers of flow channels, which can recirculate and mix the water that needs to be returned from the anoxic zone, aerobic zone, and sedimentation zone.

[0076] like Figure 13 As shown, in one embodiment, the bottom of the mixing zone 30 uses gravity-fed water intake. The water first enters an annular water distribution chamber with annular gaps at the bottom for uniform water distribution. After distribution, the water enters the central rising zone and is lifted upwards by the lifting agitator 45. The speed of the spiral fan blades can change the force and flow rate of the flow. During the lifting process, points requiring recirculation are accelerated by narrowing the diameter and then connected to a return pipe. The throat 27, which requires the flow to two or more layers, is narrowed to allow for the recirculation and mixing of water from the anoxic zone, aerobic zone, and sedimentation zone.

[0077] like Figure 14 As shown, in one embodiment, the bottom of the mixing zone 30 uses gravity-fed water intake. The water first enters an annular water distribution chamber with annular gaps at the bottom for even water distribution. After distribution, the water enters the central rising zone, where it is lifted upwards by the lifting agitator 45. The rotation speed of the spiral fan blades can change the force and flow rate of the flow. Points requiring return flow during the lifting process are accelerated by narrowing the diameter before connecting to a return pipe. The impeller is mainly arranged in the upper region.

[0078] like Figure 15 As shown, in one embodiment, the bottom of the mixing zone 30 uses gravity-fed water intake, and the spiral fan blades are configured with unequal diameters.

[0079] like Figure 16 As shown, in one embodiment, the bottom of the mixing zone 30 uses gravity-fed water intake. After rebounding from the bottom plate, the water rises due to the lifting action of the lifting agitator 45. After water distribution, it enters the central rising zone, where it is further lifted upwards by the lifting agitator 45. The rotation speed of the spiral fan blades can change the force and flow rate of the flow. Then, a return pipe is connected. The spiral fan blades are arranged in an independent hopper, and the return pipe is connected inside the hopper, allowing the water that needs to be returned from the anoxic zone, aerobic zone, sedimentation zone, etc., to return to the central mixing zone. Obviously, the above embodiments are merely examples for clear illustration and are not intended to limit the implementation. For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A variable-density self-circulating sludge granulation device, characterized in that, include: Anoxic tank (1), aerobic tank (2), and sedimentation tank (3) are set up along the water flow path; A water acceleration device is installed in the anoxic pool (1), including a throat (27) and at least one nozzle (28). The throat (27) is covered on the top of the nozzle (28). The water from the outside is accelerated by the nozzle (28) and enters the throat (27). The water is then released from the top of the throat (27) into the anoxic pool (1). The return main pipe (4) is provided with a sludge return branch pipe (5) extending into the sedimentation tank (3) and / or a nitrification liquid return branch pipe (6) extending into the aerobic tank (2) at the inlet end of the return main pipe (4). The return main pipe (4) is provided with a first pipe section (7) extending into the anoxic tank (1) and located in the throat pipe (27). The first pipe section (7) uses the negative pressure in the throat pipe (27) to introduce sludge and / or nitrification liquid into the throat pipe (27). The outlet end of the return main pipe (4) is also provided with a second pipe section (8) extending toward the anoxic pool (1) and located outside the throat pipe (27). A ventilation pipe (9) extends into the second pipe section (8) at one end and is adapted to be connected to a gas source at the other end. The ventilation pipe (9) introduces gas into the second pipe section (8) and uses the air lifting effect to introduce sludge and / or nitrification liquid into the anoxic tank (1). The drain pipe (39) extends inward into the bottom of the sedimentation tank (3) at one end and outward to the outside of the sedimentation tank (3) at the other end. It also includes a degassing channel (12); The degassing channel (12) is located between the aerobic tank (2) and the sedimentation tank (3). The cross-sectional area of ​​the downstream channel in the degassing channel (12) is larger than that of the upstream channel. The water in the aerobic tank (2) is degassed in the degassing channel (12) and then enters the sedimentation tank (3). The nitration return branch (6) is located inside the degassing channel (12).

2. The variable density self-circulating sludge granulation device according to claim 1, characterized in that, It also includes a lightweight sludge hopper (10); The lightweight sludge hopper (10) is located at one end of the sludge return branch pipe (5) away from the return main pipe (4), and the opening of the lightweight sludge hopper (10) is facing upward.

3. The variable density self-circulating sludge granulation device according to claim 1, characterized in that, It also includes an aerobic water inlet distribution tank (11), which is located between the aerobic tank (2) and the anoxic tank (1). The water in the anoxic tank (1) first enters the aerobic water inlet distribution tank (11) and then enters the aerobic tank (2). The second pipe section (8) is located inside the aerobic water inlet distribution tank (11).

4. The variable density self-circulating sludge granulation device according to claim 3, characterized in that, The nitration return branch pipe (6) has its opening facing downwards and is located in the downstream channel of the degassing channel (12).

5. The variable density self-circulating sludge granulation device according to claim 3, characterized in that, A first return water inlet (13) is provided between the degassing channel (12) and the aerobic tank (2). A portion of the water in the degassing channel (12) enters the downstream sedimentation tank (3), and another portion of the water flows back to the upstream aerobic tank (2) through the first return water inlet (13).

6. The variable density self-circulating sludge granulation device according to claim 5, characterized in that, An aeration device is provided in the aerobic tank (2), which includes an aerator (14) and an accelerator. The aerator (14) is located at the bottom of the aerobic tank (2) and is used to provide the gas required for the aerobic reaction; The acceleration component includes a premixing cover (15) and a speed-maintaining component (16); The premixing hood (15) is installed over the air outlet of the aerator (14), and the space between the premixing hood (15) and the aerator (14) forms a first premixing zone (17); a gap is left between the premixing hood (15) and the aerator (14) to form a second return water inlet (18), which connects the interior and exterior spaces of the first premixing zone (17); wherein the flow area of ​​the release port of the premixing hood (15) is smaller than the flow area of ​​the inlet of the premixing hood (15) to increase the pressure in the first premixing zone (17) under aeration conditions; One end of the speed-maintaining component (16) is connected to the release port of the premixed cover (15), and the other end extends in a direction away from the premixed cover (15).

7. The variable density self-circulating sludge granulation device according to claim 6, characterized in that, It also includes a partition plate (19) disposed in the lower half of the aerobic tank (2), the partition plate (19) dividing the lower half of the aerobic tank (2) into multiple aeration zones (21), and the aeration device is disposed in the aeration zone (21). The space between two adjacent aeration zones (21) forms an internal return channel (20). The bottom of the partition plate (19) and the bottom of the aerobic tank (2) are separated by a gap that connects the aeration zone (21) and the internal return channel (20). The water flow direction in the internal return channel (20) is opposite to that in the aeration zone (21). The bottom of the internal return channel (20) is provided with a guide cone (22) to guide the water in the internal return channel (20) back to the aeration zone (21).

8. The variable density self-circulating sludge granulation device according to claim 1, characterized in that, A sludge filter layer (23) is formed in the sedimentation tank (3). The lower layer of the sludge filter layer (23) is a nitrification filter layer (25), and the upper layer of the sludge filter layer (23) is a denitrification filter layer (24). The sludge filter layer (23) filters the water while the nitrification filter layer (25) removes ammonia nitrogen from the water and the denitrification filter layer (24) removes total nitrogen and COD from the water.

9. The variable density self-circulating sludge granulation device according to claim 2, characterized in that, It also includes a sludge discharge pipe (26), one end of which is connected to the light sludge hopper, and the other end extends to the outside of the aerobic tank (2).

10. The variable density self-circulating sludge granulation device according to claim 3, characterized in that, The anoxic tank (1) consists of a mixing zone (30), an upflow anoxic zone (33), an anaerobic diversion channel (34), and an upflow anaerobic reaction zone (35) along the water flow path. The nozzle (28) and the throat (27) are both located in the mixing zone (30). A third return water inlet (29) is left between the nozzle (28) and the throat (27). A portion of the water in the mixing zone (30) flows back to the throat (27) through the third return water inlet (29). Another part of the water in the mixing zone (30) flows out from the bottom and enters the upflow anoxic zone (33). The water flows upward to the top in the upflow anoxic zone (33) and then enters the anaerobic guide channel (34). The water in the anaerobic guide channel (34) flows downward to the bottom and then enters the upflow anaerobic reaction zone (35). The water in the upflow anaerobic reaction zone (35) flows upward to the top and then enters the aerobic inlet water distribution tank (11).

11. The variable density self-circulating sludge granulation device according to claim 10, characterized in that, It also includes the anaerobic effluent weir (36) and the anaerobic water distribution pipe (37); The anaerobic effluent weir (36) is located at the top of the upflow anaerobic reaction zone (35). After the water enters the anaerobic effluent weir (36), it is then transported to the aerobic inlet water distribution tank (11). The inlet end of the anaerobic water distribution pipe (37) is connected to the anaerobic flow channel (34), and the outlet end of the anaerobic water distribution pipe (37) is set parallel to the bottom of the upflow anaerobic reaction zone (35) so that the inlet water is evenly distributed at the bottom of the upflow anaerobic reaction zone (35).

12. The variable density self-circulating sludge granulation device according to claim 10, characterized in that, It also includes an anoxic reflux tube (38), one end of which extends into the throat tube (27), and the other end is located in the upflow anaerobic reaction zone (35); The anoxic return pipe (38) has its opening facing upward and extends into the upper half of the upflow anaerobic reaction zone (35) so that the anaerobic wastewater in the upflow anaerobic reaction zone (35) is returned to the mixing zone (30).

13. The variable density self-circulating sludge granulation device according to claim 1, characterized in that, The anoxic tank (1), aerobic tank (2) and sedimentation tank (3) are integrated into one tank body, and the different areas divided in the tank body form the anoxic tank (1), aerobic tank (2) and sedimentation tank (3). Alternatively, one or more of the anoxic tank (1), aerobic tank (2), and sedimentation tank (3) may be composed of separate tank bodies.

14. The variable density self-circulating sludge granulation device according to claim 10, characterized in that, It also includes a lifting agitator (45) disposed within the mixing zone (30) for accelerating the rise of water within the throat (27).

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