Circular post-positioned sludge internal carbon source denitrification sewage nitrogen and phosphorus removal treatment device

Abstract

The utility model belongs to the technical field of sewage treatment, and particularly relates to a circular rear sludge internal carbon source denitrification sewage nitrogen and phosphorus removal treatment device which comprises a device foundation, an outer circular ring and an inner circular ring, and the outer circular ring and the inner circular ring are fixed on the device foundation and coaxially arranged in a sleeving manner and define an annular space; partition walls are arranged in the annular space and divide the annular space into an anaerobic tank, an aerobic tank and a sludge tank, and an anoxic tank is formed in the inner circular ring; the anaerobic tank, the aerobic tank and the anoxic tank are sequentially connected, an anaerobic water inlet pipe is arranged on the anaerobic tank, a mud-water separation area is arranged in the anaerobic tank, the top of the mud-water separation area is communicated with the aerobic tank so that sewage enters the aerobic tank, and a water outlet pipe and a sludge discharge pipe connected with the sludge tank are connected to the anoxic tank; and the circular post-positioned sludge internal carbon source denitrification sewage nitrogen and phosphorus removal treatment device comprises a sludge flow distribution pipe for conveying the sludge at the bottom of the sludge-water separation area into the anoxic tank.

Description

Technical Field

[0001] This utility model belongs to the technical field of wastewater treatment, specifically relating to a circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device. Background Technology

[0002] Currently, most domestic wastewater treatment plants in China use the A / A / O process (anaerobic-anoxic-aerobic process) to treat wastewater. In the A / A / O process, wastewater flows sequentially through an anaerobic tank, an anoxic tank, and an aerobic tank. Under anaerobic conditions, polysaccharide-accumulating bacteria in the sludge adsorb and store organic carbon sources in the wastewater, while simultaneously releasing phosphorus. Under anoxic conditions, denitrifying bacteria utilize the organic carbon sources stored in the sludge to perform denitrification, converting nitrates and nitrites in the wastewater into nitrogen gas, thus removing nitrogen from the wastewater. Under aerobic conditions, nitrifying bacteria nitrify ammonia nitrogen in the wastewater, converting nitrates into nitrates and nitrites, while polyphosphate-accumulating bacteria adsorb phosphorus, thereby removing phosphorus from the wastewater. To prevent substandard wastewater from being directly discharged from the aerobic tank and to provide nitrates and nitrites to the anoxic tank, the nitrified liquid in the aerobic tank needs to be recycled back to the anoxic tank, and the recycling ratio is usually relatively large.

[0003] However, domestic sewage in my country generally has a low carbon-to-nitrogen ratio. When treating sewage with a low carbon-to-nitrogen ratio, a large amount of carbon source needs to be added, resulting in high operating costs. Furthermore, an excessively high nitrification liquid recirculation ratio will lead to even lower carbon and nitrogen levels in the anoxic tank, resulting in low denitrification efficiency and increasing the amount of carbon source input. Utility Model Content

[0004] This invention provides a circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device to solve the technical problem of high operating costs caused by the need to add external carbon sources in the wastewater treatment process in the prior art.

[0005] To solve the above problems, the circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device provided by this utility model adopts the following technical solution: A circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device includes a device foundation and an outer ring and an inner ring fixed on the device foundation and coaxially sleeved. The outer ring and the inner ring together form an annular space. A partition wall is provided in the annular space and divides the annular space into an anaerobic tank, an aerobic tank and a sludge tank. An anoxic tank is formed inside the inner ring.

[0006] The anaerobic tank, aerobic tank, and anoxic tank are connected in sequence. The anaerobic tank is equipped with an anaerobic inlet pipe and has a mud-water separation zone. The top of the mud-water separation zone is connected to the aerobic tank so that sewage can enter the aerobic tank. The anoxic tank is connected with an outlet pipe and a sludge discharge pipe connected to the sludge tank.

[0007] The circular post-sludge carbon source denitrification wastewater denitrification and phosphorus removal treatment device includes a sludge distribution pipe that transports sludge from the bottom of the sludge-water separation zone to the anoxic tank.

[0008] Beneficial effects: By switching the positions of the aerobic and anoxic tanks, wastewater first enters the aerobic tank and then the anoxic tank. The sludge-water separation zone in the anaerobic tank separates the wastewater and sludge. The sludge containing internal carbon sources directly enters the anoxic tank, where the organic carbon source of the sludge is fully utilized to denitrify the nitrifying liquid, thus achieving highly efficient denitrification without the need for external carbon sources. The wastewater discharged from the anaerobic tank contains relatively little organic carbon source, and even if consumed, it will not affect the denitrification process in the anoxic tank. On the one hand, the anoxic tank has a large amount of organic carbon source for denitrification, eliminating the need for external carbon sources and saving on operation and maintenance costs; on the other hand, the nitrifying liquid does not need to be recycled, further reducing operation and maintenance costs.

[0009] As a further improvement, the anaerobic tank is equipped with at least two baffle walls, which are staggered between any two adjacent baffle walls to allow the sewage to flow back and forth within the anaerobic tank. This back-and-forth flow of sewage and sludge within the anaerobic tank prolongs the anaerobic reaction time, allowing polysaccharitrophs and polyphosphate-accumulating bacteria to fully adsorb and store the organic carbon sources in the sewage, thus maximizing the adsorption, transfer, and storage of organic carbon sources in the sewage.

[0010] As a further improvement, at least two of the baffle walls divide the interior of the anaerobic tank into a head chamber, an intermediate chamber, and a tail chamber. The tail chamber has a larger volume than the head chamber and the intermediate chamber to reduce the flow velocity of wastewater in the tail chamber, thereby forming the mud-water separation zone in the tail chamber.

[0011] As a further improvement, the aerobic tank is equipped with an integrated biofilm aeration device. This device includes a support frame within the aerobic tank, on which biological packing material for nitrifying bacteria to attach, and microporous aerators. The biological packing material allows longer-lived nitrifying bacteria to attach for an extended period, while shorter-lived polyphosphate-accumulating bacteria quickly detach and remain suspended, creating a symbiotic environment between the sludge and the biofilm. This increases the number of nitrifying bacteria in the aerobic tank, resolves the conflict between the short and long lifespans of nitrifying bacteria and polyphosphate-accumulating bacteria, and achieves both membrane nitrification and phosphorus removal, ensuring efficient biological nitrification and phosphorus removal.

[0012] As a further improvement, the anoxic tank is equipped with a clarifier, a wastewater distribution pipe and an anoxic tank aerator. The clarifier is used to separate sludge and water. The clarifier has a side inlet for the mixed liquor to enter and a bottom outlet for the sludge to be returned to the anoxic tank. The top of the clarifier is equipped with a water collection tank connected to the outlet pipe. The water collection tank is used to collect clean water.

[0013] The sewage distribution pipe is laid horizontally and one end is connected to the sludge distribution pipe, while the other end is connected to an anoxic inlet pipe that is connected to the aerobic tank, so that the sludge transported from the anaerobic tank and the nitrification liquid transported from the aerobic tank are mixed in the sewage distribution pipe. The bottom of the sewage distribution pipe is also provided with nozzles that spray the mixed liquid towards both sides of the clarifier.

[0014] The aerators in the anoxic tank are located on both sides of the clarifier / separator. These aerators are either medium-hole or large-hole aerators, and they spray air upwards. By installing the clarifier / separator, wastewater distribution pipes, and aerators within the anoxic tank, four functions are achieved: sludge-water mixing, reaction, sedimentation, and sludge self-recirculation. This extends the denitrification time within the anoxic tank, allowing for the full utilization of organic carbon sources within the sludge through denitrification.

[0015] As a further improvement, the anoxic tank is also equipped with a baffle located below the bottom outlet. The baffle is used to block the upward flow of the mixed liquor, and a return slit is formed between the baffle and the clarifier to allow sludge to flow back into the anoxic tank.

[0016] As a further improvement, the baffle has a triangular cross-section, with its apex extending into the bottom outlet.

[0017] As a further improvement, a first sludge airlift device is provided in the anaerobic tank. The first sludge airlift device includes a first sludge suction pipe extending vertically. The bottom of the first sludge suction pipe is located at the bottom of the sludge-water separation zone. The first sludge airlift device also includes a first air supply pipe that supplies air to the bottom of the first sludge suction pipe. The top of the first sludge suction pipe is connected to the sludge distribution pipe.

[0018] As a further improvement, a second sludge airlift device is provided in the sludge tank. The second sludge airlift device includes a second sludge suction pipe extending vertically, with the bottom of the second sludge suction pipe located at the bottom of the sludge tank. The second sludge airlift device also includes a second air supply pipe that supplies air to the bottom of the second sludge suction pipe. The top of the second sludge suction pipe is connected to a sludge tank inlet pipe.

[0019] As a further improvement, the top of the second sludge suction pipe is also connected to an anaerobic sludge inlet pipe, which is located on the same side of the anaerobic tank as the anaerobic inlet pipe. Using the anaerobic sludge inlet pipe, the polysaccharide-accumulating and phosphorus-accumulating sludge in the sludge tank, which is in a state of endogenous reaction starvation, is returned to the front end of the anaerobic tank to mix and contact with the untreated wastewater. This allows for the adsorption and storage of organic carbon sources in the wastewater, which are then returned to the anoxic tank for use as a carbon source for denitrification. This achieves efficient and full utilization of carbon sources within the wastewater, saving operating costs. Attached Figure Description

[0020] The above and other objects, features, and advantages of the present invention will become readily understood by reading the following detailed description of exemplary embodiments with reference to the accompanying drawings. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0021] Figure 1 A flowchart of a circular post-sludge internal carbon source denitrification wastewater nitrogen and phosphorus removal treatment device;

[0022] Figure 2 A schematic diagram of the bottom of a circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device;

[0023] Figure 3 A schematic diagram of the top of a circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device;

[0024] Figure 4 This is a schematic diagram showing the assembly of the foundation, outer ring, inner ring, walkway, and railings of a circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device.

[0025] Figure 5 This is a cross-sectional view of the wastewater distribution pipe in a circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1. Foundation; 2. Outer ring; 3. Inner ring; 4. Spiral staircase; 5. Walkway slab; 6. Railing; 7. Partition wall; 8. Anaerobic tank; 9. Aerobic tank; 10. Sludge tank; 11. Anoxic tank; 12. First baffle wall; 13. Second baffle wall; 14. Third baffle wall; 15. First end chamber; 16. Intermediate chamber; 17. End chamber; 18. Anaerobic inlet pipe; 19. Aerobic inlet pipe; 20. First sludge suction pipe; 21. Anaerobic tank aeration pipe; 22. Sludge distribution pipe; 23. Support frame; 24. 25. Packing material; 26. Microporous aerator; 27. Aerobic tank air supply pipe; 28. Anoxic tank water inlet pipe; 29. ​​Anoxic tank aerator; 30. Anoxic tank air supply pipe; 31. Sewage distribution pipe; 32. Sludge collection pipe; 33. Water outlet pipe; 34. Separation cylinder; 35. Guide plate; 36. Baffle; 37. Nozzle; 38. Sludge discharge pipe; 39. Second sludge suction pipe; 40. Sludge tank air supply pipe; 41. Sludge tank sludge inlet pipe; 42. Anaerobic sludge inlet pipe; 43. Sludge pump; 44. Sludge discharge pipe; 45. Air supply fan. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Those skilled in the art should understand that the embodiments described below are only some, not all, of the embodiments disclosed. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0029] The principles and spirit of this utility model will be explained in detail below with reference to several representative embodiments.

[0030] An embodiment of the circular post-sludge internal carbon source denitrification wastewater nitrogen and phosphorus removal treatment device provided by this utility model:

[0031] like Figures 1 to 5 As shown, the circular post-sludge carbon source denitrification wastewater denitrification and phosphorus removal treatment device (hereinafter referred to as the treatment device) includes a device foundation 1, an outer ring 2 and an inner ring 3. The device foundation 1 is formed by casting, and the outer ring 2 and the inner ring 3 are arranged coaxially and fixed on the device foundation 1.

[0032] Specifically, both the outer ring 2 and the inner ring 3 are made of corrosion-resistant metal plates, using enamel, stainless steel, or carbon steel epoxy materials.

[0033] Both the outer ring 2 and the inner ring 3 are composed of multiple rings stacked one on top of the other. During assembly, the bottom ring is first hoisted, glued, bolted, secured, and spliced. Then, the upper rings are assembled until the set height is reached. Finally, the bottom ring is welded or bolted to the embedded parts of the device foundation 1. Structural sealant is used to seal the rings.

[0034] During assembly, the inner ring 3 is assembled first, followed by the outer ring 2. After the inner ring 3 and outer ring 2 are assembled, secondary grouting and seepage prevention sealing are carried out at the junction of the inner ring 3, outer ring 2 and the device foundation 1.

[0035] After the inner ring 3 and the outer ring 2 are assembled, an annular space is formed between the inner ring 3 and the outer ring 2.

[0036] A spiral staircase 4 is fixedly installed on the outside of the outer ring 2. A walkway 5 is installed above the annular space, and railings 6 are installed on both the inner and outer sides of the walkway 5. The spiral staircase 4, walkway 5, and railings 6 are all prefabricated and bolted together on site.

[0037] The annular space is divided into an anaerobic pool 8, an aerobic pool 9, and a sludge pool 10 by three partition walls 7. An anoxic pool 11 is formed inside the inner ring 3. The partition walls 7 are made of metal plates and are fixed to the inner ring 3 and the outer ring 2 with structural sealant and bolts. The bottom of the partition walls is fixed to the foundation 1 of the device with structural sealant and chemical bolts.

[0038] Anaerobic tank 8, aerobic tank 9 and anoxic tank 11 are connected in sequence, that is, the sewage passes through anaerobic tank 8, aerobic tank 9 and anoxic tank 11 in sequence. The treated water in anoxic tank 11 is directly discharged and the sludge flows into sludge tank 10.

[0039] In the anaerobic tank 8, a first baffle wall 12, a second baffle wall 13, and a third baffle wall 14 are installed sequentially along the direction of sewage flow. The bottoms of the first baffle wall 12 and the third baffle wall 14 are spaced from the foundation 1, and the top of the second baffle wall 13 is spaced from the tops of the inner ring 3 and the outer ring 2, causing the sewage to flow in a zigzag pattern within the anaerobic tank 8. The first baffle wall 12, the second baffle wall 13, and the third baffle wall 141 divide the anaerobic tank 8 into four chambers: a head chamber 15, two intermediate chambers 16, and a tail chamber 17. The volumes of the head chamber 15 and the intermediate chambers 16 are smaller than the tail chamber 17, resulting in a lower flow velocity of sewage when it reaches the tail chamber 17, enabling mud-water separation and creating a mud-water separation zone inside the tail chamber 17.

[0040] An anaerobic inlet pipe 18, which is connected to the anaerobic tank 8, is installed on the outer ring 2. The anaerobic inlet pipe 18 introduces sewage into the anaerobic tank 8.

[0041] An aerobic inlet pipe 19 is installed on the partition wall 7 between the anaerobic tank 8 and the aerobic tank 9. The aerobic inlet pipe 19 is connected to the top of the mud-water separation zone, and the sewage from the top of the mud-water separation zone is fed into the aerobic tank 9.

[0042] A first sludge airlift device is installed inside the anaerobic tank 8. The first sludge airlift device includes a first sludge suction pipe 20 and an anaerobic tank air supply pipe 21. The first sludge suction pipe 20 extends vertically, with its bottom located at the bottom of the sludge-water separation zone. The anaerobic tank air supply pipe 21 supplies air to the bottom of the first sludge suction pipe 20. During the upward movement of the air, bubbles are generated in the first sludge suction pipe 20, which drives the sludge upward. The first sludge suction pipe 20 is connected to a sludge distribution pipe 22, the other end of which is connected to the anoxic tank 11, transporting the sludge at the bottom of the sludge-water separation zone to the anoxic tank 11.

[0043] An integrated biofilm aeration device is installed in aerobic tank 9. This device includes a support frame 23, biological packing material 24, a microporous aerator 25, and an aerobic tank air supply pipe 26. The biological packing material 24 is fixedly installed on the support frame 23 and provides attachment points for nitrifying bacteria. The microporous aerator 25 is also fixedly installed on the support frame 23. The aerobic tank air supply pipe 26 is connected to the microporous aerator 25 and includes a horizontal pipe and a vertical pipe. The horizontal pipe connects to the microporous aerator 25, and the vertical pipe extends upwards. During operation, the microporous aerator 25 primarily supplies oxygen, with agitation as a secondary function.

[0044] The integrated biofilm aeration device can be lifted and lowered as a whole, facilitating its installation and subsequent maintenance. In actual use, the number of integrated biofilm aeration devices can be increased as needed.

[0045] An anoxic inlet pipe 27 is installed on the inner ring 3. The anoxic inlet pipe 27 is located in the lower part of the aerobic tank 9 and guides the nitrified liquid after nitrification in the aerobic tank 9 into the anoxic tank 11.

[0046] The anoxic tank 11 is equipped with a clarifier, an anoxic tank aerator 28, an anoxic tank air supply pipe 29, a wastewater distribution pipe 30, a sludge collection pipe 31, and an effluent pipe 32. The clarifier is located in the center of the inner ring 3 and is fixed by suspension or bottom support. The clarifier includes a separation cylinder 33, a guide plate 34, and a baffle 35. The bottom of the separation cylinder 33 is conical, and a side inlet is opened on the side of the separation cylinder 33. The lower end of the guide plate 34 is located below the side inlet and extends upward from the separation cylinder 33, guiding the mixed liquid in the anoxic tank 11 into the separation cylinder 33. A bottom outlet is opened at the bottom of the separation cylinder 33. After the mixed liquid enters the separation cylinder 33, sludge-water separation occurs, and the settled sludge flows back into the anoxic tank 11 through the bottom outlet.

[0047] Baffle 35 is located below the bottom outlet, blocking it and preventing the mixed liquor from flowing directly upwards into the separation cylinder 33. A return slit is formed between baffle 35 and separation cylinder 33, allowing sludge to return to the anoxic tank 11. The cross-section of baffle 35 is triangular, with its apex extending into the bottom outlet.

[0048] A water collection tank is fixed to the top of the separator 33. The water collection tank can collect the clean water at the top of the separator. The water outlet pipe 32 is connected to the water collection tank and extends to the outside of the outer ring 2 to draw out the clean water.

[0049] The anoxic tank aerator 28 is fixed at the bottom of the anoxic tank 11 and is located on both sides of the clarifier. The anoxic tank aerator 28 here is either a medium-hole aerator or a large-hole aerator. The anoxic tank aerator 28 blows gas upward, and the rising bubbles drive the mixed liquid to flow upward.

[0050] The sewage distribution pipe 30 is placed horizontally in the anoxic tank 11. One end of the sewage distribution pipe 30 is connected to the sludge distribution pipe 22, and the other end is connected to the anoxic inlet pipe 27. The bottom of the sewage distribution pipe 30 is provided with nozzles 36 on both sides facing the clarifier. After the sludge and sewage are mixed, they are sprayed out from the nozzles. With the air lift effect of the aerator 28 in the anoxic tank, the mixed liquid flows upward.

[0051] The sludge collection pipe 31 is located below the sewage distribution pipe 30 and is used to collect sludge from the anoxic tank 11. The sludge collection pipe 31 is connected to the sludge discharge pipe 37, which is connected to the sludge tank 10.

[0052] A second sludge airlift device is installed inside the sludge tank 10. The second sludge airlift device includes a second sludge suction pipe 38 and a sludge tank air supply pipe 39. The second sludge suction pipe 38 extends vertically, with its bottom located at the bottom of the sludge tank 10. The sludge tank air supply pipe 39 supplies air to the bottom of the second sludge suction pipe 38. During the upward movement of the air, bubbles are generated in the second sludge suction pipe 38, which drives the sludge upward. The second sludge suction pipe 38 is connected to a sludge tank inlet pipe 40 and an anaerobic sludge inlet pipe 41. The sludge tank inlet pipe 40 leads to the sludge tank 10, and the anaerobic sludge inlet pipe 41 leads to the anaerobic tank 8. The anaerobic sludge inlet pipe 41 is located on the water inlet side of the anaerobic tank 8.

[0053] A sludge pump 42 is placed in the sludge tank 10, and a sludge discharge pipe 43 is installed on the sludge pump 42. The sludge pump 42 and the sludge discharge pipe 43 discharge the sludge in the sludge tank 10.

[0054] The treatment device also includes an air supply fan 44, which is connected to the anaerobic tank air supply pipe 21, the aerobic tank air supply pipe 26, the anoxic tank air supply pipe 29, and the sludge tank air supply pipe 39.

[0055] The treatment device also includes a monitoring section, which includes an online acid-base monitor, an online oxidation-reduction potential monitor, and an online sludge concentration monitor for monitoring anaerobic tank 8; an online acid-base monitor, an online sludge concentration monitor, and an online dissolved oxygen monitor for monitoring aerobic tank 9; and an online dissolved oxygen monitor and an online sludge concentration monitor for monitoring anoxic tank 11.

[0056] Operating Procedure: Wastewater enters the anaerobic tank 8 through the anaerobic inlet pipe 18, along with sludge introduced through the anaerobic sludge inlet pipe 41. The wastewater and sludge flow back and forth and mix within the anaerobic tank 8. Polysaccharitrophs and polyphosphate-accumulating bacteria in the sludge absorb and store the organic carbon source in the wastewater under anaerobic conditions and with a high organic carbon source, while polyphosphate-accumulating bacteria fully release phosphorus. The mixture of wastewater and sludge is separated in the sludge-water separation zone. The wastewater at the top enters the aerobic tank 9 through the aerobic inlet pipe 19, while the sludge at the bottom is treated by the first sludge airlift device and then transported to the anoxic tank through the sludge distribution pipe 22.

[0057] After the wastewater enters the aerobic tank 9, an integrated biofilm aeration device installed within the aerobic tank 9 creates a symbiotic environment of biological sludge and film. Nitrifying bacteria attach to the biological packing material 24, while polyphosphate-accumulating bacteria are suspended in the aerobic tank 9 and settle after absorbing phosphorus. The nitrifying bacteria growing on the biological packing material 24 treat the ammonia nitrogen in the wastewater, converting it into nitrates and nitrites. Simultaneously, polyphosphate-accumulating bacteria absorb excess phosphorus under aerobic conditions. The nitrified liquid formed after the aerobic reaction enters the anoxic tank 11 through the anoxic inlet pipe 27.

[0058] The sludge in the sludge distribution pipe 22 and the nitrified liquid in the anoxic inlet pipe 27 both enter the wastewater distribution pipe 30 for mixing and are sprayed out from the nozzle. The sprayed mixture continues to mix with the sludge returned from the clarifier. Under anoxic conditions, denitrifying and phosphorus-removing bacteria utilize the organic carbon source in the sludge for denitrification, converting nitrates and nitrites in the wastewater into nitrogen gas and further absorbing phosphorus, nitrifying the organic carbon source stored in the sludge, and simultaneously achieving wastewater denitrification, phosphorus removal, and sludge regeneration. The mixture after the anoxic reaction flows into the separation cylinder 33 of the clarifier for sludge-water separation. The upper layer of clear water is discharged through the collection tank and outlet pipe 32, while the lower layer of sludge is returned to the anoxic tank 11. Part of it mixes with the mixture sprayed from the wastewater distribution pipe 30 and undergoes anoxic reaction, while the other part enters the sludge collection pipe 31 and is transported to the sludge tank 10.

[0059] After being processed by the second sludge air-lift device, part of the sludge in sludge tank 10 is returned to sludge tank 10, and part enters the anaerobic sludge inlet pipe 41 and then enters the anaerobic tank 8. The sludge in sludge tank 10 is in a state of starved endogenous reaction, and entering the anaerobic tank 8 enhances the adsorption and storage of organic carbon sources in the wastewater.

[0060] In the above embodiments, the outer ring 2, inner ring 3, partition wall 7, first baffle wall 12, second baffle wall 13, and third baffle wall 14 are all fabricated from prefabricated metal materials and assembled on-site. During assembly, structural adhesive is used to seal the plates together with bolts, and the bottom is fixed to the pre-embedded steel in the device foundation 1. This prefabricated assembly method reduces on-site work, improves installation efficiency, and achieves factory prefabrication and assembly installation. It solves the problems of long construction periods, significant environmental and climatic influences on construction, large labor requirements, and inconsistent construction precision and quality associated with traditional construction methods.

[0061] In other embodiments, the treatment device can be constructed using reinforced concrete casting, and can be divided into three construction schemes: fully above ground, fully underground, and semi-above ground, depending on hydraulic requirements. Reinforced concrete tank structures are robust and durable, and are currently the traditional implementation method.

[0062] In other embodiments, in order to transport the sludge at the bottom of the sludge-water separation zone in the anaerobic tank 8 to the anoxic tank 11, the sludge distribution pipe 22 can be extended directly to the bottom of the sludge-water separation zone and a pump can be installed on the sludge distribution pipe 22 for transportation.

[0063] In addition, in the description of this specification, "multiple" means at least two, such as two, three or more, etc., unless otherwise expressly and specifically defined.

Claims

1. A circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device, characterized in that, It includes the device foundation and an outer ring and an inner ring fixed to the device foundation and coaxially fitted together. The outer ring and the inner ring together form an annular space. The annular space is equipped with partition walls and divides the annular space into an anaerobic pool, an aerobic pool and a sludge pool. An anoxic pool is formed inside the inner ring. The anaerobic tank, aerobic tank, and anoxic tank are connected in sequence. The anaerobic tank is equipped with an anaerobic inlet pipe and has a mud-water separation zone. The top of the mud-water separation zone is connected to the aerobic tank so that sewage can enter the aerobic tank. The anoxic tank is connected with an outlet pipe and a sludge discharge pipe connected to the sludge tank. The circular post-sludge carbon source denitrification wastewater denitrification and phosphorus removal treatment device includes a sludge distribution pipe that transports sludge from the bottom of the sludge-water separation zone to the anoxic tank.

2. The circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device according to claim 1, characterized in that, The anaerobic tank is equipped with at least two baffle walls, which are staggered between any two adjacent baffle walls to allow the sewage to flow back and forth within the anaerobic tank.

3. The circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device according to claim 2, characterized in that, At least two of the aforementioned baffle walls divide the interior of the anaerobic tank into a head chamber, an intermediate chamber, and a tail chamber. The tail chamber has a larger volume than the head chamber and the intermediate chamber to reduce the flow velocity of wastewater in the tail chamber, thereby forming the mud-water separation zone within the tail chamber.

4. The circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device according to claim 1, 2, or 3, characterized in that, The aerobic tank is equipped with an integrated biofilm aeration device, which includes a support frame located in the aerobic tank. The support frame is equipped with biological packing material for nitrifying bacteria to attach to and a microporous aerator.

5. The circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device according to claim 1, 2, or 3, characterized in that, The anoxic tank is equipped with a clarifier, a wastewater distribution pipe, and an anoxic tank aerator. The clarifier is used to separate sludge and water. The clarifier has a side inlet for the mixed liquor to enter and a bottom outlet for the settled sludge to flow back into the anoxic tank. The top of the clarifier is equipped with a water collection tank connected to the outlet pipe, which is used to collect clean water. The sewage distribution pipe is laid horizontally and one end is connected to the sludge distribution pipe, while the other end is connected to an anoxic inlet pipe that is connected to the aerobic tank, so that the sludge transported from the anaerobic tank and the nitrification liquid transported from the aerobic tank are mixed in the sewage distribution pipe. The bottom of the sewage distribution pipe is also provided with nozzles that spray the mixed liquid towards both sides of the clarifier. The aerators in the anoxic tank are located on both sides of the clarifier. The aerators in the anoxic tank are either medium-hole or large-hole aerators, and the aerators in the anoxic tank spray air upwards.

6. The circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device according to claim 5, characterized in that, The anoxic tank is also equipped with a baffle located below the bottom outlet. The baffle is used to block the upward flow of the mixed liquor, and a return slit is formed between the baffle and the clarifier to allow sludge to flow back into the anoxic tank.

7. The circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device according to claim 6, characterized in that, The baffle has a triangular cross-section, with its apex extending into the bottom outlet.

8. The circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device according to claim 1, 2, or 3, characterized in that, The anaerobic tank is equipped with a first sludge air-lift device, which includes a first sludge suction pipe extending vertically. The bottom of the first sludge suction pipe is located at the bottom of the sludge-water separation zone. The first sludge air-lift device also includes a first air supply pipe that supplies air to the bottom of the first sludge suction pipe. The top of the first sludge suction pipe is connected to the sludge distribution pipe.

9. The circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device according to claim 1, 2, or 3, characterized in that, The sludge tank is equipped with a second sludge air lifting device, which includes a second sludge suction pipe extending vertically. The bottom of the second sludge suction pipe is located at the bottom of the sludge tank. The second sludge air lifting device also includes a second air supply pipe that supplies air to the bottom of the second sludge suction pipe. The top of the second sludge suction pipe is connected to a sludge tank inlet pipe.

10. The circular post-sludge internal carbon source denitrification wastewater denitrification and phosphorus removal treatment device according to claim 9, characterized in that, The top of the second suction pipe is also connected to an anaerobic sludge inlet pipe, which is located on the same side of the anaerobic tank as the anaerobic water inlet pipe.

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