Continuous-flow aerobic granular sludge cultivation device and method

Abstract

This invention belongs to the field of wastewater biological treatment technology and discloses a continuous flow aerobic granular sludge cultivation device and method. The device includes an influent pump, an influent pipe, an anaerobic tank, an anoxic tank, an aerobic tank, and a multi-hopper sedimentation tank connected in sequence. This invention has the advantages of rapid granule formation, stable operation, and high nitrogen and phosphorus removal efficiency.

Description

Technical Field

[0001] This invention belongs to the field of wastewater biological treatment technology, and more specifically, relates to a continuous flow aerobic granular sludge cultivation device and method. Background Technology

[0002] Aerobic granular sludge is a biological aggregate with a unique morphological structure, distinct from other biofilms. The granulation process of aerobic sludge requires no carrier; it involves the interaction of cells through biological, physical, and chemical processes under external environmental conditions, forming a microbial aggregate with excellent settling properties, high microbial biomass, strong resistance to shock loads, and a regular shape. Compared to traditional flocculent activated sludge, granular sludge has advantages such as a more compact structure, larger biomass, faster settling rate, and easier simultaneous nitrification and denitrification. Because aerobic granular sludge combines the advantages of both activated sludge and biofilm aerobic biological treatment technologies, and also possesses partial anoxic and anaerobic biological treatment capabilities, it exhibits unique superiority in terms of biomass, oxygen utilization rate, and treatment effect.

[0003] Currently, aerobic granular sludge is more commonly used in sequencing batch reactor (SBR) processes. This is because, due to the different operating modes of the processes, mechanisms that promote particle growth, such as starvation-feast, selective pressure, and particle screening, are difficult to achieve in continuous flow. Furthermore, sludge recirculation and digestate recirculation are prone to particle breakage due to water pumps. In continuous flow, the aerobic granulation efficiency is relatively low, and granular sludge does not have an advantage.

[0004] Therefore, the present invention urgently needs to propose a continuous flow aerobic granular sludge cultivation device and method. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a continuous-flow aerobic granular sludge cultivation device and method. This invention offers advantages such as rapid granule formation, stable operation, and high nitrogen and phosphorus removal efficiency.

[0006] To achieve the above objectives, the present invention provides a continuous flow aerobic granular sludge cultivation device, the device comprising an inlet pump, an inlet pipe, an anaerobic tank, an anoxic tank, an aerobic tank, and a multi-bucket sedimentation tank connected in sequence.

[0007] The inlet pipe is equipped with an anaerobic tank inlet valve and an anaerobic tank inlet flow meter.

[0008] Sludge concentration meters are installed inside the anaerobic tank and at its outlet; stirrers are installed inside both the anaerobic tank and the anoxic tank.

[0009] The bottom of the multi-hopper sedimentation tank is equipped with multiple sludge collection hoppers. Each sludge collection hopper is connected to a sludge return branch pipe and a sludge discharge branch pipe. Each sludge return branch pipe is equipped with a sludge return valve. All sludge return branch pipes are connected to the sludge inlet end of the sludge return main pipe through a sludge return pump. The sludge outlet end of the sludge return main pipe is connected to the sludge inlet of the anaerobic tank. The sludge return main pipe is equipped with a sludge return flow meter and an anaerobic tank sludge inlet valve.

[0010] In this invention, each valve is used to control the entry or discharge of sewage or sludge; each flow meter is used to measure the amount of sewage or sludge entering or discharging.

[0011] According to the present invention, preferably, a water distributor is provided at the bottom of the anaerobic tank, and an outlet weir is provided at the upper part of the anaerobic tank; the water inlet pump is connected to the water distributor through an inlet pipe.

[0012] According to the present invention, preferably, the device is provided with a plurality of anaerobic tanks.

[0013] According to the present invention, preferably, the water distribution device is a perforated pipe that is evenly distributed horizontally at the bottom of the anaerobic tank, and the opening direction of the perforated pipe is obliquely downward at 0-90°.

[0014] According to the present invention, preferably, the device further includes a carbon source replenishment device and a phosphorus removal agent replenishment device, which are connected to the anaerobic tank. In the present invention, when the carbon-to-nitrogen ratio of the influent in the inlet pipe is low, a carbon source can be added to enhance nitrogen and phosphorus removal; when the phosphorus content of the influent in the inlet pipe is high, a phosphorus removal agent can be added to enhance phosphorus removal.

[0015] According to the present invention, preferably, the outlet of the aerobic tank is divided into two paths, one of which is connected to the inlet of the multi-bucket sedimentation tank, and the other path is connected to the inlet of the anoxic tank in sequence through a nitrification liquid return pump and a nitrification liquid return pipe.

[0016] According to the present invention, preferably, a nitrification liquid reflux flow meter is provided on the nitrification liquid reflux pipe.

[0017] According to the present invention, preferably, a DO meter is installed in the aerobic tank.

[0018] According to the present invention, preferably, a plurality of aeration discs are provided at the bottom of the aerobic tank, and the aeration discs are connected to a blower through aeration pipes.

[0019] According to the present invention, preferably, both the nitrification liquor return pump and the sludge return pump are positive displacement pumps; more preferably, each of the nitrification liquor return pump and the sludge return pump is independently a diaphragm pump or a screw pump. In the present invention, positive displacement pumps have less damaging effect on sludge particles, are less likely to break sludge particles, and are beneficial to the cultivation of aerobic granular sludge.

[0020] According to the present invention, preferably, each sludge discharge branch pipe is provided with a sludge discharge valve, all sludge discharge branch pipes are connected to the sludge discharge main pipe, and the sludge discharge main pipe is provided with a sludge discharge flow meter.

[0021] According to the present invention, preferably, the outlet of the multi-bucket sedimentation tank is connected to a drain pipe; a drainage rectifier plate is provided at the outlet of the multi-bucket sedimentation tank, and an inlet rectifier plate is provided at the inlet of the multi-bucket sedimentation tank.

[0022] According to the present invention, preferably, the bottom of the multi-bucket sedimentation tank is provided with 2-10 sludge collection hoppers.

[0023] Another aspect of the present invention provides a method for cultivating continuous flow aerobic granular sludge, the method employing the aforementioned system and comprising the following steps:

[0024] S1: The anaerobic tank is operated in sequence with separate water inlet and recirculation water inlet processes;

[0025] When the separate water intake process is running, the sludge inlet valve of the anaerobic tank and the agitator in the anaerobic tank are closed. Water is introduced through the inlet pipe so that the raw sludge-water mixture of the anaerobic tank flows into the anoxic tank and the aerobic tank in sequence, and the sludge concentration in the anaerobic tank is controlled to be 10-50% of the sludge concentration in the tank at the beginning of the water intake process. After the water intake of the anaerobic tank in the separate water intake process reaches the preset value, the return water intake process is run.

[0026] When the reflux water intake process is running, the sludge inlet valve of the anaerobic tank and the agitator in the anaerobic tank are opened, so that the sludge in the sludge collection hopper near the inlet of the multi-hopper sedimentation tank is returned to the anaerobic tank, thereby making the sludge concentration in the anaerobic tank reach the sludge concentration in the tank at the beginning of the anaerobic tank water intake.

[0027] S2: The mud-water mixture discharged from the aerobic tank is introduced into the multi-hopper sedimentation tank to obtain settled sludge in the sludge collection hopper near the inlet of the multi-hopper sedimentation tank, settled sludge in the sludge collection hopper far from the inlet of the multi-hopper sedimentation tank, and supernatant.

[0028] According to the present invention, preferably, the sludge concentration in the anaerobic tank at the beginning of water inflow is 2500-8000 mg / L.

[0029] According to the present invention, preferably, the preset value is 30%-60% of the volume of the anaerobic tank.

[0030] In this invention:

[0031] When the device is first started and the separate water intake process is running: a small water intake is required to start the device to ensure that no sludge flows out of the drain pipe from the multi-hopper sedimentation tank; after the sludge enters the multi-hopper sedimentation tank, larger particles will settle in the sludge collection hopper at the front end, and smaller particles will settle in the sludge collection hopper at the rear end. Open the sludge return valve corresponding to the sludge collection hopper at the front end to return the larger particles to the anaerobic tank, and open the sludge discharge valve corresponding to the sludge collection hopper at the rear end to discharge the smaller particles from the device.

[0032] As the sludge particles increase in size, more sludge will settle in the sludge collection hopper at the front end, while there will be almost no sludge in the sludge collection hopper at the back end. At this point, the water inflow can be increased, and the water inflow can be gradually increased to full capacity.

[0033] As the sludge particle size continues to increase, even at maximum load, more sludge will settle in the sludge collection hopper at the front. At this point, appropriately adjust the sludge return valve and sludge discharge valve to return the largest particles from the front to the anaerobic tank, while maintaining the sludge discharge rate and keeping the sludge concentration within the set range of 2500-8000 mg / L. Furthermore, when the sludge volume in the rear sludge collection hopper is low, the sludge discharge valve can be opened intermittently or not at all.

[0034] According to the present invention, preferably, the influent rising velocity of the anaerobic tank in the separate influent process is greater than the sludge settling velocity of the anaerobic tank. Preferably, the influent rising velocity of the anaerobic tank in the separate influent process is 1 m / h to 7 m / h. In the present invention, as the cultivation proceeds, the sludge settling velocity in the anaerobic tank increases. Therefore, the present invention increases the influent rising velocity of the anaerobic tank in the separate influent process from 1 m / h to 7 m / h.

[0035] According to the present invention, preferably, the method further includes adding a carbon source and a phosphorus removal agent to the anaerobic tank during the operation of the separate water intake process. Preferably, the carbon source is at least one of sodium acetate, sodium propionate, glucose and methanol, and the phosphorus removal agent is at least one of polyaluminum chloride, aluminum sulfate, ferric sulfate and polyaluminum ferric chloride.

[0036] According to the present invention, preferably, the amount of sludge settled in the sludge collection hopper of the multi-hopper sedimentation tank returned to the anaerobic tank is 50%-200% of the influent volume of the anaerobic tank in the separate influent process.

[0037] According to the present invention, preferably, the single-cycle operation time of the reflux water intake process is 0.5-2 times the single-cycle operation time of the individual water intake process.

[0038] According to the present invention, preferably, the retention time of the anaerobic tank is 1-3 hours, the retention time of the anoxic tank is 1-5 hours, the retention time of the aerobic tank is 3-15 hours, and the retention time of the multi-bucket sedimentation tank is 1-3 hours.

[0039] According to the present invention, preferably, a portion of the mud-water mixture discharged from the aerobic tank enters the multi-hopper sedimentation tank, and the remaining portion is sequentially returned to the anoxic tank through a nitrification liquid return pump and a nitrification liquid return pipe.

[0040] According to the present invention, preferably, the DO value of the aerobic tank is controlled at 0.5-4 mg / L.

[0041] According to the present invention, preferably, the amount of mud-water mixture returned from the aerobic tank to the anoxic tank is 100%-600% of the influent volume of the anaerobic tank in the separate influent process.

[0042] According to the present invention, preferably, the method further includes discharging the settled sludge in the sludge collection hopper in the multi-hopper sedimentation tank away from the inlet of the multi-hopper sedimentation tank sequentially through the sludge discharge branch pipe and the sludge discharge main pipe, and discharging the supernatant through the drain pipe.

[0043] The beneficial effects of the technical solution of this invention are as follows: This invention solves the problem that mechanisms promoting particle growth, such as starvation-feast, selective pressure, and particle screening, are difficult to achieve in continuous flow reactors, resulting in low aerobic granulation efficiency and a lack of dominance of granular sludge in continuous flow. This invention can fully realize the effects of starvation-feast and selective pressure in a continuous flow reactor, promoting particle formation; larger sludge in the multi-hopper sedimentation tank is returned to the anaerobic tank, while smaller sludge discharge devices achieve particle screening; this invention has the advantages of rapid particle formation, stable operation, and high nitrogen and phosphorus removal efficiency. Specifically:

[0044] 1. In this invention, the anaerobic tank separate water inlet process and the recirculation water inlet process are operated in turn, which can fully realize the starvation-feast and selective pressure effect in the continuous flow reactor, and promote particle formation. When operating a separate influent process, fresh wastewater is evenly distributed into the lower end of the anaerobic tank through a flow distributor, pushing out the existing sludge and water in the anaerobic tank. The rising speed of the fresh wastewater is controlled to be slightly greater than the settling speed of the sludge. The lighter sludge is carried out of the anaerobic tank, while the larger and heavier sludge remains. The larger and heavier sludge remaining in the anaerobic tank rapidly absorbs carbon sources from the fresh wastewater, allowing them to grow more quickly. The lighter sludge, which is not exposed to fresh wastewater, grows more slowly. This achieves biological selective pressure, promoting the gradual transformation of the sludge in the biological tank into larger and heavier aerobic granular sludge. In addition, the larger and heavier sludge comes into direct contact with the fresh wastewater, absorbing a large amount of organic matter. After sufficient aeration in the aerobic section, the absorbed organic matter is fully consumed, achieving a saturation-starvation process and promoting the rapid formation of aerobic granular sludge.

[0045] 2. In this invention, when the sludge enters the multi-hopper sedimentation tank, larger and heavier sludge enters more of the sludge collection hopper closer to the inlet of the multi-hopper sedimentation tank, while lighter sludge enters more of the sludge collection hopper farther from the inlet of the multi-hopper sedimentation tank. Moreover, the farther away from the inlet, the smaller the sludge particle size in the sludge collection hopper. By discharging the sludge in the sludge collection hopper farther from the inlet of the multi-hopper sedimentation tank from the reactor, and leaving the larger and heavier sludge to flow back into the front-end anaerobic tank, the screening of granular sludge is achieved.

[0046] 3. In this invention, excellent nitrogen and phosphorus removal effects are achieved both during and after the formation of aerobic granular sludge. In the separate influent process, fresh wastewater directly contacts the sludge after entering the anaerobic tank, where there is no oxygen or oxides, allowing full utilization of the organic matter in the fresh wastewater to release phosphorus. After the wastewater and returned sludge enter the anoxic tank, denitrification and phosphorus uptake occur, significantly removing total nitrogen and some phosphorus from the water. In the aerobic tank, ammonia nitrogen is converted into nitrate nitrogen or nitrite nitrogen through nitrification. Simultaneously, due to the layered structure of the aerobic granular sludge, the inner layer contains more phosphorus-removing and denitrifying bacteria, while the outer layer contains more nitrifying bacteria. The aerobic granular sludge exhibits strong simultaneous nitrification and denitrification in the aerobic tank, removing some total nitrogen. Furthermore, polyphosphate-accumulating bacteria can excessively absorb phosphorus in the aerobic tank, thereby achieving phosphorus removal.

[0047] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0048] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0049] Figure 1 A schematic diagram of the continuous flow aerobic granular sludge cultivation device provided by the present invention is shown.

[0050] Figure 2 The diagram shows the changes in sludge characteristics of the continuous flow aerobic granular sludge cultivation method provided in Embodiment 1 of the present invention (wherein, "SVI refers to the sludge volume index, which is the volume occupied by 1g of dry sludge after sedimentation of the aeration mixture (in mL), unit mL / g").

[0051] Explanation of reference numerals in the attached figures:

[0052] 1. Anaerobic tank; 2. Anoxic tank; 3. Aerobic tank; 4. Multi-hopper sedimentation tank; 5. Inlet pump; 6. Agitator; 7. Blower; 8. Nitrification liquor return pump; 9. Sludge return pump; 10. Water distribution device; 11. Effluent weir; 12. Aeration disc; 13. Anaerobic tank inlet valve; 14. Anaerobic tank sludge inlet valve; 15. Sludge return valve; 16. Sludge discharge valve; 17. Anaerobic tank inlet flow meter; 18. 19. Nitrification liquor return flow meter; 20. Sludge return flow meter; 21. Sludge discharge flow meter; 22. Sludge collection hopper; 23. Inlet rectifier plate; 24. Drainage rectifier plate; 25. Inlet pipe; 26. Nitrification liquor return pipe; 27. Sludge return main pipe; 28. Drainage pipe; 29. ​​Sludge discharge main pipe; 30. Sludge concentration meter in the anaerobic tank; 31. Sludge concentration meter at the outlet of the anaerobic tank; 32. DO meter. Detailed Implementation

[0053] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0054] Example 1

[0055] This embodiment provides a continuous flow aerobic granular sludge cultivation device, such as... Figure 1 As shown, the device includes an inlet pump 5, an inlet pipe 24, an anaerobic tank 1, an anoxic tank 2, an aerobic tank 3, and a multi-bucket sedimentation tank 4 connected in sequence.

[0056] The inlet pipe 24 is equipped with an anaerobic tank inlet valve 13 and an anaerobic tank inlet flow meter 17.

[0057] The device is equipped with two anaerobic tanks 1;

[0058] Sludge concentration meters are installed inside the anaerobic tank 1 and at its outlet. Agitators 6 are installed inside both the anaerobic tank 1 and the anoxic tank 2. A water distributor 10 is installed at the bottom of the anaerobic tank 1, and an outlet weir 11 is installed at the top of the anaerobic tank 1. The inlet pump 5 is connected to the water distributor 10 via an inlet pipe 24. The water distributor 10 is a perforated pipe evenly distributed horizontally at the bottom of the anaerobic tank 1, with the opening direction of the perforated pipe being inclined downward at 0-90°.

[0059] The outlet of the aerobic tank 3 is divided into two paths. One path is connected to the inlet of the multi-bucket sedimentation tank 4, and the other path is connected to the inlet of the anoxic tank 2 through the nitrification liquid return pump 8 and the nitrification liquid return pipe 25. The nitrification liquid return pipe 25 is equipped with a nitrification liquid return flow meter 18. The aerobic tank 3 is equipped with a DO meter 31. Multiple aeration discs 12 are installed at the bottom of the aerobic tank 3. The aeration discs 12 are connected to the blower 7 through aeration pipes.

[0060] The bottom of the multi-hopper sedimentation tank 4 is provided with four sludge collection hoppers 21. Each sludge collection hopper 21 is connected to a sludge return branch pipe and a sludge discharge branch pipe. Each sludge return branch pipe is equipped with a sludge return valve 15. All sludge return branch pipes are connected to the sludge inlet end of the sludge return main pipe 26 through a sludge return pump 9. The sludge outlet end of the sludge return main pipe 26 is connected to the sludge inlet of the anaerobic tank 1. The sludge return flow meter 19 and the anaerobic tank sludge inlet valve 14 are provided on the sludge return main pipe 26. Each sludge discharge branch pipe is equipped with a sludge discharge valve 16, and all sludge discharge branch pipes are connected to the sludge discharge main pipe 28. The sludge discharge main pipe 28 is equipped with a sludge discharge flow meter 20. The outlet of the multi-hopper sedimentation tank 4 is connected to a drain pipe 27. A drainage rectifier plate 23 is installed at the outlet of the multi-hopper sedimentation tank 4, and an inlet rectifier plate 22 is installed at the inlet of the multi-hopper sedimentation tank 4.

[0061] The nitrification liquid return pump 8 and the sludge return pump 9 are screw pumps;

[0062] The device is also equipped with a carbon source replenishment device and a phosphorus removal agent replenishment device (not shown), which are connected to the anaerobic tank 1.

[0063] This embodiment uses the above-mentioned device for continuous flow aerobic granular sludge cultivation, including the following steps:

[0064] S1: The anaerobic tank 1 is operated in sequence with a separate water inlet process and a recirculation water inlet process;

[0065] The influent is fresh domestic sewage, with influent COD of 187-378 mg / L, influent ammonia nitrogen of 26-39 mg / L, influent total nitrogen of 33-47 mg / L, and influent total phosphorus of 1.9-4.5 mg / L;

[0066] The residence time in both anaerobic tanks 1 was 1.5 hours, the residence time in anoxic tank 2 was 4 hours, and the residence time in aerobic tank 3 was 10 hours.

[0067] When the separate water intake process is running, the sludge inlet valve 14 of the anaerobic tank and the agitator in the anaerobic tank are closed. Water is introduced through the inlet pipe 24, allowing the raw sludge-water mixture from the anaerobic tank 1 to flow sequentially into the anoxic tank 2 and the aerobic tank 3. The sludge concentration in the anaerobic tank 1 is controlled to be 10-50% of the initial sludge concentration (3000-4500 mg / L) at the start of the anaerobic tank water intake process. The process continues until the anaerobic tank water intake volume reaches a preset value (the preset value is the volume of the anaerobic tank). After 30%-60%, the reflux influent process is run; wherein, in this embodiment, sodium acetate is added to the anaerobic tank 1 during the separate influent process as a carbon source to enhance nitrogen and phosphorus removal; and the influent rising speed of the anaerobic tank 1 during the separate influent process needs to be greater than the sludge settling speed of the anaerobic tank. As the cultivation proceeds, the sludge settling speed in the anaerobic tank 1 increases. Therefore, in this embodiment, the influent rising speed of the anaerobic tank 1 during the separate influent process is gradually increased from 1 m / h to 7 m / h.

[0068] When the recirculation influent process is operated, the sludge inlet valve 14 of the anaerobic tank and the agitator in the anaerobic tank are opened, so that the settled sludge in the sludge collection hopper 21 near the inlet of the multi-hopper sedimentation tank 4 is returned to the anaerobic tank 1, thereby making the sludge concentration in the anaerobic tank reach the sludge concentration in the tank at the beginning of the anaerobic tank influent process; wherein, the amount of settled sludge returned to the anaerobic tank in the sludge collection hopper of the multi-hopper sedimentation tank is 50%-200% of the anaerobic tank influent volume of the separate influent process; the single cycle operation time of the recirculation influent process is 0.5-2 times the single cycle operation time of the separate influent process;

[0069] S2: A portion of the mud-water mixture discharged from the aerobic tank 3 enters the multi-bucket sedimentation tank 4, and the remaining portion is sequentially returned to the anoxic tank 2 through the nitrification liquid return pump 8 and the nitrification liquid return pipe 25.

[0070] The mud-water mixture entering the multi-bucket sedimentation tank 4 yields settled sludge in the sludge collection hopper near the inlet of the multi-bucket sedimentation tank, settled sludge in the sludge collection hopper away from the inlet of the multi-bucket sedimentation tank, and supernatant.

[0071] The DO value of the aerobic tank 3 is controlled at 0.5-4 mg / L; the amount of sludge-water mixture returned from the aerobic tank 3 to the anoxic tank 2 is 100%-600% of the influent volume of the anaerobic tank in the separate influent process; in this embodiment, the settled sludge in the sludge collection hopper in the multi-hopper sedimentation tank, which is far from the inlet of the multi-hopper sedimentation tank, is discharged from the device in sequence through the sludge discharge branch pipe and the sludge discharge main pipe 28, and the supernatant is discharged from the device through the drain pipe 27.

[0072] After 45 days of operation, the device in this embodiment resulted in a sludge particle size (median diameter) increase to 407 μm and a sludge SVI decrease to 45 g / mL. (See attached image.) Figure 2 Therefore, it can be seen that aerobic granular sludge was cultivated in this embodiment.

[0073] Example 2

[0074] This embodiment provides a continuous flow aerobic granular sludge cultivation device. The only difference between this device and Embodiment 1 is that:

[0075] The nitrification liquid return pump 8 and the sludge return pump 9 are diaphragm pumps;

[0076] The bottom of the multi-bucket sedimentation tank 4 is equipped with 5 sludge collection hoppers 21.

[0077] The apparatus of this embodiment is used for continuous flow aerobic granular sludge cultivation. The only difference between this embodiment and Embodiment 1 is that:

[0078] The influent is fresh industrial wastewater, a mixture of industrial and domestic sewage. The influent COD is 455-738 mg / L, the influent ammonia nitrogen is 49-68 mg / L, the influent total nitrogen is 60-81 mg / L, and the influent total phosphorus is 4.8-10.1 mg / L.

[0079] The residence time in both anaerobic tanks 1 was 2 hours, the residence time in anoxic tank 2 was 5 hours, and the residence time in aerobic tank 3 was 14 hours.

[0080] The initial sludge concentration in the anaerobic tank during the initial influent intake was 4000-6500 mg / L;

[0081] In this embodiment, PAC is also added to the anaerobic tank 1 during the operation of the separate water intake process as a phosphorus removal agent to assist in phosphorus removal.

[0082] After 60 days of operation, the sludge particle size (median diameter) of the device in this embodiment increased to 278 μm, and the sludge SVI decreased to 48 g / mL. Therefore, this embodiment also successfully cultivated aerobic granular sludge.

[0083] Example 3

[0084] This embodiment provides a continuous flow aerobic granular sludge cultivation device. The only difference between this device and Embodiment 1 is that:

[0085] The device does not include a carbon source replenishment device or a phosphorus removal agent replenishment device.

[0086] The apparatus of this embodiment is used for continuous flow aerobic granular sludge cultivation. The only difference between this embodiment and Embodiment 1 is that:

[0087] The influent is the effluent from an anaerobic reactor in a certain factory. The influent COD is 623-899 mg / L, the influent ammonia nitrogen is 25-31 mg / L, the influent total nitrogen is 39-51 mg / L, and the influent total phosphorus is 5.5-9.6 mg / L.

[0088] The residence time in both anaerobic tanks 1 was 2 hours, the residence time in anoxic tank 2 was 3 hours, and the residence time in aerobic tank 3 was 12 hours.

[0089] The initial sludge concentration in the anaerobic tank during the initial influent intake was 5000-6000 mg / L;

[0090] After 40 days of operation, the sludge particle size (median diameter) of the device in this embodiment increased to 553 μm, and the sludge SVI decreased to 44 g / mL. Therefore, this embodiment also successfully cultivated aerobic granular sludge.

[0091] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for culturing continuous-flow aerobic granular sludge, characterized by, The device used in the method comprises a water inlet pump, a water inlet pipe, an anaerobic tank, an anoxic tank, an aerobic tank and a multi-bucket sedimentation tank connected in sequence; The water inlet pipe is provided with an anaerobic tank water inlet valve and an anaerobic tank water inlet flow meter; The anaerobic tank is provided with a sludge concentration meter at the inside and the water outlet of the anaerobic tank respectively; the inside of the anaerobic tank and the inside of the anoxic tank are both provided with a stirrer; The inside bottom of the anaerobic tank is provided with a water distribution device, and the upper part of the inside of the anaerobic tank is provided with a water outlet weir; the water inlet pump is connected with the water distribution device through the water inlet pipe; The bottom of the multi-bucket sedimentation tank is provided with a plurality of sludge collecting buckets; each sludge collecting bucket is correspondingly connected with a sludge backflow branch pipe and a sludge discharge branch pipe below; each sludge backflow branch pipe is provided with a sludge backflow valve; all the sludge backflow branch pipes are connected with the sludge backflow pump and the sludge backflow main pipe through the sludge inlet end; the sludge backflow main pipe is connected with the sludge inlet of the anaerobic tank through the sludge outlet end; the sludge backflow main pipe is provided with a sludge backflow flow meter and an anaerobic tank sludge inlet valve; The method comprises the following steps: S1: sequentially operating the anaerobic tank in a separate water inlet process and a backflow water inlet process; When the separate water inlet process is operated, the anaerobic tank sludge inlet valve and the stirrer in the anaerobic tank are closed; the original sludge water mixture in the anaerobic tank is sequentially flowed into the anoxic tank and the aerobic tank through the water inlet pipe; and the sludge concentration in the anaerobic tank is controlled to be 10-50% of the sludge concentration in the anaerobic tank at the beginning of the anaerobic tank water inlet; after the anaerobic tank water inlet amount in the separate water inlet process reaches a preset value, the backflow water inlet process is operated; The anaerobic tank water inlet rising speed in the separate water inlet process is greater than the sludge sedimentation speed of the anaerobic tank; The preset value is 30%-60% of the volume of the anaerobic tank; When the backflow water inlet process is operated, the anaerobic tank sludge inlet valve and the stirrer in the anaerobic tank are opened; the sludge in the sludge collecting bucket near the water inlet of the multi-bucket sedimentation tank in the multi-bucket sedimentation tank is backflowed to the anaerobic tank; and the sludge concentration in the anaerobic tank reaches the sludge concentration in the anaerobic tank at the beginning of the anaerobic tank water inlet; S2: the sludge water mixture discharged from the aerobic tank is flowed into the multi-bucket sedimentation tank; the sludge in the sludge collecting bucket near the water inlet of the multi-bucket sedimentation tank in the multi-bucket sedimentation tank, the sludge in the sludge collecting bucket far from the water inlet of the multi-bucket sedimentation tank in the multi-bucket sedimentation tank and the supernatant are obtained.

2. The continuous flow aerobic granular sludge cultivation method according to claim 1, wherein The device is provided with a plurality of anaerobic tanks; The water distribution device is a perforated pipe uniformly distributed on the inside bottom of the anaerobic tank in the horizontal direction; the opening direction of the perforated pipe is 0-90° downward obliquely.

3. The continuous flow aerobic granular sludge cultivation method according to claim 2, wherein The device is further provided with a carbon source supplementing device and a phosphorus removal agent supplementing device; the carbon source supplementing device and the phosphorus removal agent supplementing device are connected with the anaerobic tank.

4. The continuous-flow aerobic granular sludge cultivation process according to claim 1 of the present application, wherein, The water outlet of the aerobic tank is divided into two routes; one route is connected with the water inlet of the multi-bucket sedimentation tank; the other route is sequentially connected with the water inlet of the anoxic tank through a nitrification liquid backflow pump and a nitrification liquid backflow pipe; The nitrification liquid reflux pipe is provided with a nitrification liquid reflux flow meter; The aerobic tank is provided with a DO detector; The bottom of the aerobic tank is provided with a plurality of aeration discs connected with a blower through an aeration pipeline; The nitrification liquid reflux pump and the sludge reflux pump are both volumetric pumps.

5. The continuous-flow aerobic granular sludge cultivation process according to claim 4, wherein, The nitrification liquid reflux pump and the sludge reflux pump are independently diaphragm pumps or screw pumps.

6. The continuous-flow aerobic granular sludge cultivation method according to claim 1, wherein, Each sludge discharge branch pipe is provided with a sludge discharge valve, and all the sludge discharge branch pipes are connected with a sludge discharge main pipe provided with a sludge discharge flow meter; The multi-bucket sedimentation tank is connected with a drain pipe at the water outlet, and is provided with a water discharge rectifier plate at the water outlet and a water inlet rectifier plate at the water inlet; The bottom of the multi-bucket sedimentation tank is provided with 2-10 sludge collecting buckets.

7. The continuous-flow aerobic granular sludge cultivation method according to claim 1, wherein, The sludge concentration in the anaerobic tank at the beginning of water inlet is 2500-8000 mg / L; The water inlet rising speed of the anaerobic tank in the separate water inlet process is 1 m / h-7 m / h; The method further comprises adding carbon source and phosphorus removal agent into the anaerobic tank during the operation of the separate water inlet process.

8. The continuous-flow aerobic granular sludge cultivation method according to claim 7, wherein, The carbon source is at least one of sodium acetate, sodium propionate, glucose and methanol, and the phosphorus removal agent is at least one of polyaluminum chloride, aluminum sulfate, ferric sulfate and polyaluminum ferric chloride.

9. The continuous-flow aerobic granular sludge cultivation method according to claim 1, wherein, The amount of the sedimentation sludge in the sludge collecting bucket of the multi-bucket sedimentation tank refluxed to the anaerobic tank is 50%-200% of the water inlet amount of the anaerobic tank in the separate water inlet process; The single-cycle operation time of the reflux water inlet process is 0.5-2 times of the single-cycle operation time of the separate water inlet process.

10. The continuous-flow aerobic granular sludge cultivation method according to claim 1, wherein, The residence time of the anaerobic tank is 1-3 h, the residence time of the anoxic tank is 1-5 h, the residence time of the aerobic tank is 3-15 h, and the residence time of the multi-bucket sedimentation tank is 1-3 h.

11. The continuous-flow aerobic granular sludge cultivation method according to claim 1, wherein, Part of the sludge-water mixture discharged from the aerobic tank enters the multi-bucket sedimentation tank, and the remaining part is sequentially refluxed to the anoxic tank through the nitrification liquid reflux pump and the nitrification liquid reflux pipe; The DO value of the aerobic tank is controlled at 0.5-4 mg / L; The amount of the sludge-water mixture refluxed from the aerobic tank to the anoxic tank is 100%-600% of the water inlet amount of the anaerobic tank in the separate water inlet process.

12. The method of claim 1, wherein the continuous flow aerobic granular sludge cultivation method is performed in a sequencing batch reactor (SBR) or a continuous flow reactor (CFR). The method further comprises sequentially discharging the sedimentation sludge in the sludge collecting bucket of the multi-bucket sedimentation tank away from the water inlet of the multi-bucket sedimentation tank from the device through the sludge discharge branch pipe and the sludge discharge main pipe, and discharging the supernatant from the device through the drain pipe.

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