Float sludge self-reflux anaerobic ammonia oxidation reactor and denitrification method thereof

Abstract

The invention discloses a float sludge self-reflux type anaerobic ammonia oxidation reactor and a denitrification method thereof, and relates to the technical field of anaerobic ammonia oxidation reactors, the float sludge self-reflux type anaerobic ammonia oxidation reactor comprises an oxidation reaction tank, a vacuum pump, an effluent weir and rotational flow water distribution pipes, the outer side of the oxidation reaction tank is provided with a water distribution mechanism, and the water distribution mechanism is connected with the rotational flow water distribution pipes through a plurality of groups of rotational flow water distribution pipes; nitrogen-containing wastewater enters a plurality of groups of jet devices through a water inlet ring pipe, inlet water, gas, liquid and solid phases are fully mixed and then flow into an upper denitrification reaction area of an oxidation reaction tank through a rotational flow water distribution pipe, a degassing mechanism is arranged right above the oxidation reaction tank, and the nitrogen-containing wastewater enters a nitrogen removal reaction area of the oxidation reaction tank through a vacuum pump arranged at the top end of the degassing mechanism. And discharging the gas of the sludge by using a vacuum pump. Through jet flow water inlet and negative pressure sludge suction, floating sludge self-backflow is achieved, on one hand, sludge loss is greatly reduced, the sludge retention is enhanced, the sludge concentration is improved, on the other hand, separation of sludge and gas is promoted through negative pressure suction, and sludge granulation is facilitated.

Description

Technical Field

[0001] This invention relates to the technical field of anaerobic ammonia oxidation reactors, specifically to a floating sludge self-recirculation type anaerobic ammonia oxidation reactor and its denitrification method. Background Technology

[0002] Anaerobic ammonia oxidation technology has become a core direction for solving the problem of denitrification of high ammonia nitrogen wastewater due to its energy-saving and aeration-reducing, low-carbon, no need for external carbon sources, and high-efficiency nitrogen removal load. However, the anaerobic ammonia oxidation bacteria, which are the core of this process, grow slowly, have low biomass proliferation and low cell density, and are easily lost with the effluent in the flow reactor, resulting in a decline in denitrification performance.

[0003] With the in-depth research and engineering application of anaerobic ammonia oxidation technology, the currently realized engineering projects mainly adopt the forms of flocculent / granular mixed sludge + packing + sedimentation and granular sludge + reactor. The former uses packing with biofilm formation as the core, supplemented by sedimentation tank to intercept sludge, which has the problems of large footprint and low sludge load. The latter uses the cultivation of high-load anaerobic ammonia oxidation granular sludge as the core, which has a small footprint and high sludge load. However, the high sludge load is accompanied by a large amount of gas production, which leads to sludge floating and loss. Existing anaerobic ammonia oxidation reactors, such as Chinese patent authorization announcement numbers: CN223033214U and CN222846472U, are prone to sludge floating and agglomeration during operation, and are lost with the effluent. This not only wastes the microbial culture, but also reduces the denitrification effect of the reactor. Therefore, it is necessary to develop a reactor that can achieve self-recirculation of floating sludge and sludge retention. Summary of the Invention

[0004] The purpose of this invention is to provide a floating sludge self-recirculation anaerobic ammonia oxidation reactor and its denitrification method, so as to solve the above-mentioned defects caused by the prior art.

[0005] A floating sludge self-recirculation anaerobic ammonia oxidation reactor includes an oxidation reaction tank, a vacuum pump, an effluent weir, and swirl distribution pipes. A water distribution mechanism is installed on the outside of the oxidation reaction tank. Nitrogenous wastewater enters through multiple sets of swirl distribution pipes via an inlet ring pipe and multiple sets of ejectors. After thorough mixing of the gas, liquid, and solid phases of the influent, the wastewater flows through the swirl distribution pipes into the upper denitrification reaction zone of the oxidation reaction tank. A degassing mechanism is installed directly above the oxidation reaction tank. This degassing mechanism uses a vacuum pump installed at the top to discharge gas from the sludge, and utilizes negative pressure suction to promote the separation of sludge and gas.

[0006] Preferably, the water distribution mechanism includes jet injectors, an inlet ring pipe, a sludge return pipe, an outlet weir, an outlet pipe, a guide plate, and a vortex water distribution pipe. An inlet ring pipe is provided on the outside of the oxidation reaction tank. Multiple sets of jet injectors are arranged in a ring around the outside of the inlet ring pipe. The rear end of the jet injector is connected to the vortex water distribution pipe. Guide plates are symmetrically arranged at the bottom inside the oxidation reaction tank. The inlet end of the jet injector is connected to the outside of the inlet ring pipe and the outside of the sludge return pipe. The outlet end of the jet injector is connected to the vortex water distribution pipe. The outlet weir is installed inside the oxidation reaction tank.

[0007] Preferably, the top of the sludge return pipe is connected to a sludge suction funnel outlet end, and the top plane of the sludge suction funnel is flush with the outlet plane of the effluent weir.

[0008] Preferably, the degassing mechanism includes a vacuum pump, a degassing tank, an exhaust pipe, a sludge riser pipe, a sludge downcomer pipe, and a three-phase separator. The inlet end of the sludge riser pipe is connected to the three-phase separator. The bottom outlet end of the degassing tank is connected to the top end of the sludge downcomer pipe. The bottom end of the sludge downcomer pipe is connected to the bottom end of the oxidation reaction tank. The output end of the vacuum pump is connected to the degassing tank. The degassing tank is located directly above the oxidation reaction tank. The bottom end of the vacuum pump is located directly above the degassing tank. One side of the exhaust pipe is connected to the side of the effluent weir. The three-phase separator is installed inside the oxidation reaction tank.

[0009] Preferably, the degassing tank is connected to one end of the exhaust pipe via a vacuum pump located at its top.

[0010] Preferably, the outlet of the vortex water distribution pipe is tangent to the circular cross-section of the oxidation reaction tank and faces downwards, and the angle between the outlet of the vortex water distribution pipe and the bottom plate of the oxidation reaction tank is in the range of 30°-60°.

[0011] Preferably, the oxidation reactor is connected to one side of the effluent weir via a through-pipe. The horizontal distance between the center of the effluent weir and the suction nozzle and the effluent weir is 1 / 8 or 1 / 4 of the horizontal distance between the center of the horizontal cross-section of the oxidation reactor and the effluent weir.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] 1. This invention achieves self-recirculation of floating sludge through jet water inlet and negative pressure sludge suction. On the one hand, it greatly reduces sludge loss, enhances sludge retention, and increases sludge concentration. On the other hand, it utilizes negative pressure suction to promote the separation of sludge and gas, which is beneficial for sludge granulation. The outlet of the swirl distribution pipe is tangential to the circular cross-section of the oxidation reactor and tilts downward. The mixed liquid forms a stable swirl in the upper denitrification reaction zone of the oxidation reactor through tangential injection, which enhances sludge-water contact and mass transfer efficiency, and provides a uniform reaction environment for subsequent denitrification reactions.

[0014] 2. This invention achieves thorough mixing of the gas, liquid, and solid phases of the influent through a jet injector for water intake and sludge suction. Simultaneously, the swirl distribution pipe allows the wastewater and floating sludge gas to be fully mixed and contacted with the granular sludge in the reactor in a swirling manner, enhancing solid-liquid mass transfer and improving denitrification efficiency. The reactor in this invention can be standardized, serialized, and integrated into a set of reaction devices according to the influent water volume, and has great potential for widespread application. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention;

[0016] Figure 2 This is a schematic diagram of the top cross-section of the oxidation reaction vessel in this invention;

[0017] Figure 3 This is a top view of the oxidation reaction vessel in this invention;

[0018] Figure 4 This is a schematic diagram of the internal structure of the oxidation reaction vessel in this invention;

[0019] Figure 5 This is a top view of the oxidation reaction vessel in this invention.

[0020] in:

[0021] 1. Oxidation reactor; 2. Ejector; 3. Inlet ring pipe; 4. Sludge return pipe; 5. Water distribution mechanism; 6. Vacuum pump; 7. Degassing tank; 8. Exhaust pipe; 9. Outlet weir; 10. Degassing mechanism; 11. Outlet pipe; 12. Sludge riser pipe; 13. Sludge downcomer pipe; 14. Three-phase separator; 15. Sludge suction bell mouth; 16. Baffle plate; 17. Swirl water distribution pipe. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0023] like Figures 1 to 5As shown, a floating sludge self-recirculation anaerobic ammonia oxidation reactor includes an oxidation reaction tank 1, a vacuum pump 6, an effluent weir 9, and a swirl distribution pipe 17. A water distribution mechanism 5 is provided on the outside of the oxidation reaction tank 1. The water distribution mechanism 5, through multiple sets of swirl distribution pipes 17, allows nitrogen-containing wastewater to enter multiple sets of ejectors 2 via an inlet ring pipe 3. After the gas, liquid, and solid phases of the inlet water are fully mixed, the wastewater flows into the upper denitrification reaction zone of the oxidation reaction tank 1 through the swirl distribution pipes 17. A degassing mechanism 10 is provided directly above the oxidation reaction tank 1. The degassing mechanism 10, through the vacuum pump 6 at the top, uses the vacuum pump 6 to discharge the gas from the sludge and uses negative pressure suction to promote the separation of sludge and gas.

[0024] The water distribution mechanism 5 includes jet ejectors 2, an inlet ring pipe 3, a sludge return pipe 4, an outlet weir 9, an outlet pipe 11, a guide plate 16, and a vortex water distribution pipe 17. An inlet ring pipe 3 is provided on the outside of the oxidation reaction tank 1. Multiple sets of jet ejectors 2 are arranged in a ring around the outside of the inlet ring pipe 3. The rear end of each jet ejector 2 is connected to the vortex water distribution pipe 17. Guide plates 16 are symmetrically arranged at the bottom inside the oxidation reaction tank 1. The inlet end of each jet ejector 2 is connected to the outside of the inlet ring pipe 3 and the outside of the sludge return pipe 4. 2. The outlet end is connected to the vortex water distribution pipe 17, and the outlet weir 9 is installed inside the oxidation reaction tank 1; the top end of the sludge return pipe 4 is connected to the outlet end of the sludge suction funnel 15, and the top plane of the sludge suction funnel 15 is flush with the outlet horizontal plane of the outlet weir 9; the oxidation reaction tank 1 is connected to one side of the outlet weir 9 through the outlet pipe 11, and the horizontal distance between the center of the outlet weir 9 and the center of the sludge suction funnel 15 and the outlet weir 9 is 1 / 8 or 1 / 4 of the horizontal distance between the center of the horizontal cross section of the oxidation reaction tank 1 where the outlet horizontal plane is located and the horizontal distance between the outlet weir 9 and the outlet horizontal plane.

[0025] The jet injector 2 distributes wastewater evenly to multiple sets of vortex distribution pipes 17 through the annular water distribution of the inlet ring pipe 3. The outlet of the vortex distribution pipe 17 is tangent to the circular cross-section of the tank and tilted downward at 30°-60° to form a spiral vortex. This design breaks the local concentration gradient of traditional point water distribution, allowing wastewater to mix rapidly with the returned floating sludge and the gas drawn in, eliminating the reaction dead zone and increasing the contact probability of ammonia nitrogen, nitrite nitrogen and granular sludge.

[0026] The degassing mechanism 10 includes a vacuum pump 6, a degassing tank 7, an exhaust pipe 8, a sludge riser pipe 12, a sludge downcomer pipe 13, and a three-phase separator 14. The inlet end of the sludge riser pipe 12 is connected to the three-phase separator 14. The bottom outlet end of the degassing tank 7 is connected to the top end of the sludge downcomer pipe 13. The bottom end of the sludge downcomer pipe 13 is connected to the bottom end of the oxidation reaction tank 1. The output end of the vacuum pump 6 is connected to the degassing tank 7. The degassing tank 7 is positioned directly above the oxidation reaction tank 1. The bottom of the vacuum pump 6 is located directly above the degassing tank 7. One side of the exhaust pipe 8 is connected to the side of the water outlet weir 9. The three-phase separator 14 is installed inside the oxidation reaction tank 1. The degassing tank 7 is connected to one end of the exhaust pipe 8 through the vacuum pump 6 located at the top. The outlet direction of the swirl water distribution pipe 17 is tangent to the circular cross-section of the oxidation reaction tank 1 and faces downward. The angle between the outlet of the swirl water distribution pipe 17 and the bottom plate of the oxidation reaction tank 1 is in the range of 30°-60°.

[0027] The negative pressure generated by vacuum pump 6 not only discharges nitrogen gas, but also reduces the pressure inside oxidation reaction tank 1, promoting the further escape of residual nitrogen gas inside granular sludge, avoiding the increase in mass transfer resistance caused by gas accumulation in sludge, and ensuring the continuous and efficient operation of the reaction. The sludge suction nozzle 15 is flush with the water discharge weir 9, accurately intercepting the floating nitrogen-containing sludge, which is returned to ejector 2 through sludge return pipe 4. The negative pressure of ejector 2 further strips nitrogen gas from the sludge, and the separated sludge re-participates in the mixing process.

[0028] In practical applications, this type of floating sludge self-recirculation anaerobic ammonia oxidation reactor includes the following operations:

[0029] Step 1: The nitrogen-containing wastewater, which mainly contains pollutants such as ammonia nitrogen and nitrite nitrogen, first enters the inlet ring pipe 3 outside the oxidation reaction tank 1 through the external pipeline. The inlet ring pipe 3 is arranged in a ring around the oxidation reaction tank 1, and multiple sets of ejectors 2 are evenly connected to its outside. The wastewater is distributed to the inlet end of each ejector 2 through the inlet ring pipe 3. The high-speed flowing wastewater forms a negative pressure in the ejector 2, which can draw in the gas inside the oxidation reaction tank 1.

[0030] Step 2: The floating sludge return pipe 4 introduces the nitrogen-containing floating sludge intercepted in the subsequent stage into the inlet end of the jet injector 2, where it is further mixed with wastewater and gas to form a mixed liquid rich in microorganisms, nutrients and gas. The mixed liquid finally enters the vortex water distribution pipe 17 through the outlet end of the jet injector 2. The outlet of the vortex water distribution pipe 17 is tangential to the circular cross section of the oxidation reaction tank 1 and is inclined downward. The mixed liquid forms a stable vortex in the upper denitrification reaction zone of the oxidation reaction tank 1 through tangential injection.

[0031] Step 3: The nitrogen gas generated by the reaction and the tiny bubbles escaping from the granular sludge are released due to the sludge floating upwards. They enter the degassing tank 7 through the gas channel of the three-phase separator 14. Most of the granular sludge settles at the three-phase separator 14 due to its high density. Some enters the degassing tank 7 through the sludge riser pipe 12. The remaining sludge continues to float upwards with the liquid phase. The vacuum pump 6 generates negative pressure, which discharges the gas through the exhaust pipe 8. At the same time, it reduces the pressure inside the tank and promotes sludge-gas separation. The separated sludge enters the degassing tank 7 through the sludge riser pipe 12 and then flows back to the bottom of the oxidation reaction tank 1 through the sludge downcomer pipe 13 to prevent sludge loss.

[0032] Step 4: The sludge suction port 15 inside the oxidation reaction tank 1 has its top plane flush with the outlet plane of the effluent weir 9, trapping the floating nitrogen-containing sludge particles. The sludge is returned to the inlet end of the ejector 2 through the floating sludge return pipe 4. At this time, the negative pressure of the ejector 2 further promotes the release of nitrogen in the sludge. The separated sludge re-participates in the wastewater mixing process, preventing the sludge from being lost with the effluent.

[0033] Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not exhaustive. All modifications within the scope of this invention or its equivalents are included in this invention.

Claims

1. A floating sludge self-recirculation anaerobic ammonia oxidation reactor, characterized in that: The system includes an oxidation reaction tank (1), a vacuum pump (6), an outlet weir (9), and a vortex water distribution pipe (17). A water distribution mechanism (5) is provided on the outside of the oxidation reaction tank (1). The water distribution mechanism (5) passes through multiple sets of vortex water distribution pipes (17). Nitrogen-containing wastewater enters multiple sets of ejectors (2) through an inlet ring pipe (3). After the gas, liquid, and solid phases of the inlet water are fully mixed, they flow into the upper denitrification reaction zone of the oxidation reaction tank (1) through the vortex water distribution pipes (17). A degassing mechanism (10) is provided directly above the oxidation reaction tank (1). The degassing mechanism (10) uses a vacuum pump (6) provided at the top to discharge the gas from the sludge. The negative pressure suction promotes the separation of sludge and gas.

2. The sludge self-recirculation anaerobic ammonia oxidation reactor according to claim 1, characterized in that: The water distribution mechanism (5) includes a jet injector (2), an inlet ring pipe (3), a sludge return pipe (4), an outlet weir (9), an outlet pipe (11), a guide plate (16), and a vortex water distribution pipe (17). An inlet ring pipe (3) is provided on the outside of the oxidation reaction tank (1). Multiple jet injectors (2) are arranged in a ring shape on the outside of the inlet ring pipe (3). The rear end of the jet injector (2) is connected to the vortex water distribution pipe (17). A guide plate (16) is symmetrically arranged at the bottom inside the oxidation reaction tank (1). The inlet end of the jet injector (2) is connected to the outside of the inlet ring pipe (3). The inlet end of the jet injector (2) is connected to the outside of the sludge return pipe (4). The outlet end of the jet injector (2) is connected to the vortex water distribution pipe (17). The outlet weir (9) is installed inside the oxidation reaction tank (1).

3. The sludge self-recirculation anaerobic ammonia oxidation reactor according to claim 2, characterized in that: The top end of the sludge return pipe (4) is connected to the outlet end of the sludge suction funnel (15), and the top plane of the sludge suction funnel (15) is flush with the outlet plane of the water weir (9).

4. The sludge self-recirculation anaerobic ammonia oxidation reactor according to claim 3, characterized in that: The degassing mechanism (10) includes a vacuum pump (6), a degassing tank (7), an exhaust pipe (8), a sludge riser pipe (12), a sludge fallr pipe (13), and a three-phase separator (14). The inlet end of the sludge riser pipe (12) is connected to the three-phase separator (14). The bottom outlet end of the degassing tank (7) is connected to the top end of the sludge fallr pipe (13). The bottom end of the sludge fallr pipe (13) is connected to the bottom end of the oxidation reaction tank (1). The output end of the vacuum pump (6) is connected to the degassing tank (7). The degassing tank (7) is located directly above the oxidation reaction tank (1). The bottom end of the vacuum pump (6) is located directly above the degassing tank (7). One side of the exhaust pipe (8) is connected to one side of the effluent weir (9). The three-phase separator (14) is installed inside the oxidation reaction tank (1).

5. The sludge self-recirculation anaerobic ammonia oxidation reactor according to claim 4, characterized in that: The degassing tank (7) is connected to one end of the exhaust pipe (8) via a vacuum pump (6) installed at the top.

6. The sludge self-recirculation anaerobic ammonia oxidation reactor according to claim 5, characterized in that: The outlet of the vortex water distribution pipe (17) is tangent to the circular cross-section of the oxidation reaction tank (1) and faces downwards. The angle between the outlet of the vortex water distribution pipe (17) and the bottom plate of the oxidation reaction tank (1) is 30°-60°.

7. The sludge self-recirculation anaerobic ammonia oxidation reactor according to claim 6, characterized in that: The oxidation reaction tank (1) is connected to one side of the outlet weir (9) through an outlet pipe (11) that runs through one side.

8. The sludge self-recirculation anaerobic ammonia oxidation reactor according to claim 7, characterized in that: The horizontal distance between the center of the outlet weir (9) and the center of the suction funnel (15) and the outlet weir (9) is 1 / 8 or 1 / 4 of the horizontal distance between the center of the horizontal cross-section of the oxidation reaction tank (1) where the outlet plane is located and the outlet weir (9).

9. A method for denitrification in a self-recirculating anaerobic ammonia oxidation reactor as described in claim 8, characterized in that: The steps are as follows: Step 1: The nitrogen-containing wastewater, which mainly contains pollutants such as ammonia nitrogen and nitrite nitrogen, first enters the inlet ring pipe outside the oxidation reaction tank through the external pipeline. The inlet ring pipe is arranged in a ring around the oxidation reaction tank, and multiple sets of ejectors are evenly connected to its outer side. The wastewater is distributed to the inlet end of each ejector through the inlet ring pipe. The high-speed flowing wastewater forms a negative pressure in the ejector, which can draw in the gas inside the oxidation reaction tank. Step 2: The sludge return pipe introduces the nitrogen-containing sludge retained in the subsequent stages into the inlet of the jet injector, where it is further mixed with wastewater and gas to form a mixed liquid rich in microorganisms, nutrients, and gas. The mixed liquid finally enters the vortex water distribution pipe through the outlet of the jet injector. The outlet of the vortex water distribution pipe is tangential to the circular cross-section of the oxidation reactor and slopes downward. The mixed liquid forms a stable vortex in the upper denitrification reaction zone of the oxidation reactor through tangential injection. Step 3: The nitrogen gas generated by the reaction and the tiny bubbles escaping from the granular sludge are released due to the sludge floating upwards. The gas enters the degassing tank through the gas channel of the three-phase separator. Most of the granular sludge settles at the three-phase separator due to its higher density. Some enters the degassing tank through the sludge riser pipe. The remaining sludge continues to float upwards with the liquid phase. The vacuum pump generates negative pressure, which discharges the gas through the exhaust pipe. At the same time, it reduces the pressure inside the tank and promotes sludge-gas separation. The separated sludge enters the degassing tank through the sludge riser pipe and then flows back to the bottom of the oxidation reaction tank through the sludge downcomer pipe to avoid sludge loss. Step 4: The sludge suction nozzle inside the oxidation reactor is flush with the effluent weir surface, trapping the floating nitrogen-containing sludge particles. The sludge is then returned to the jet injector inlet through the sludge return pipe. At this point, the negative pressure of the jet injector further promotes the release of nitrogen from the sludge. The separated sludge then re-participates in the wastewater mixing process, preventing sludge loss with the effluent.

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