A wastewater treatment device and method based on endogenous denitrification for synergistic nitrogen and carbon removal

Abstract

This invention discloses a wastewater co-treatment device and method for denitrification and carbon removal based on endogenous denitrification, comprising: a treatment tank, the upper end of which is provided with a central pipe and an upstream pipe, and the lower end of which is provided with a downstream pipe and a discharge pipe. Three treatment tanks are arranged from left to right, namely an anaerobic tank, an aerobic tank, and an anoxic tank. The upstream pipe of the anaerobic tank is connected to the central pipe of the aerobic tank via a first water guide pipe, the upstream pipe of the aerobic tank is connected to the central pipe of the anoxic tank via a second water guide pipe, and the upstream pipe of the anoxic tank is connected to a sedimentation tank via a third water guide pipe. The sedimentation tank has a drain pipe at its upper end, and the central pipe of the anaerobic tank is connected to an inlet pipe. A nucleation control device is disposed in the treatment tank for controlling the size of the dense bacterial aggregate particles in the anaerobic, aerobic, and anoxic tanks.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a wastewater treatment device and method based on endogenous denitrification and synergistic denitrification and carbon removal. Background Technology

[0002] With increasingly stringent standards for urban wastewater treatment and discharge, deep denitrification of wastewater with low carbon-to-nitrogen ratios (C / N) has become a challenge in the industry. Endogenous denitrification technology utilizes microorganisms to convert organic matter in wastewater into an intracellular carbon source—polyhydroxyalkanoates (PHA). Under anoxic conditions, this internal carbon source is used as an electron donor to reduce nitrates, achieving synergistic denitrification and carbon removal through "one carbon source serving two purposes." It has advantages such as no need for external carbon sources and low sludge production.

[0003] Currently, most treatment devices based on endogenous denitrification adopt a three-tank series structure of anaerobic-aerobic-anoxic (AOA). However, in existing devices, traditional activated sludge exists in the form of loose flocs, with poor settling performance and easy loss with the effluent, making it difficult to increase the sludge concentration in the reactor and limiting the treatment load. It is also impossible to differentiate the sludge particle morphology of the anaerobic, aerobic, and anoxic zones. Studies have shown that the anaerobic zone requires larger particle size to maintain a high sludge concentration and a strictly anaerobic microenvironment, the aerobic zone requires small to medium particle size to ensure oxygen mass transfer efficiency, and the anoxic zone requires medium particle size to form an internal anoxic microzone. A uniform particle morphology will inevitably lead to a decrease in the efficiency of a certain functional zone.

[0004] Therefore, it is necessary to provide a wastewater treatment device and method based on endogenous denitrification for synergistic nitrogen and carbon removal to solve the problems mentioned in the background art. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides the following technical solution: a wastewater synergistic denitrification and carbon removal treatment device based on endogenous denitrification, comprising:

[0006] The treatment tank has a central pipe and an upstream pipe at its upper end, and a downstream pipe and a discharge pipe at its lower end. There are three treatment tanks arranged from left to right, namely an anaerobic tank, an aerobic tank and an anoxic tank. The upstream pipe of the anaerobic tank and the central pipe of the aerobic tank are connected by a water guide pipe. The upstream pipe of the aerobic tank and the central pipe of the anoxic tank are connected by a water guide pipe. The upstream pipe of the anoxic tank is connected to a sedimentation tank by a water guide pipe. The sedimentation tank has a drain pipe at its upper end, and the central pipe of the anaerobic tank is connected to an inlet pipe.

[0007] The nucleation control device, located in the processing tank, is used to regulate the size of the dense bacterial aggregate particles in the anaerobic, aerobic, and anoxic tanks.

[0008] Preferably, the nucleation control device includes:

[0009] The ring is located on the outer wall of the lower end of the central tube inside the treatment tank;

[0010] The nucleating tube has nucleating holes arranged on its side tube wall. Its upper end tube cavity is sleeved outside the lower end of the central tube, and its upper end is connected to the ring sleeve by a spring.

[0011] The sieve cylinder is located inside the treatment tank and is fitted over the outside of the nucleation tube. Its upper end is fixed to the outer wall of the lower end of the central tube, and the lower end of the upflow pipe is connected to the cavity of the sieve cylinder. The sieve cylinder is used to retain dense bacterial aggregate particles larger than its sieve holes in its cavity.

[0012] Abrasive device is located in the lower end cavity of the nucleation tube;

[0013] The circulation pipe is connected at its lower end to the chamber between the screen cylinder and the treatment tank, and at its upper end to the central pipe cavity outside the treatment tank. A circulation pump is installed on the pipe.

[0014] A stirring device is located at the bottom of the processing tank.

[0015] Preferably, the orientation of the nucleation pores is offset from the axis of the nucleation tube, and the ring is rotatably mounted on the central tube in one direction, so that the ring can rotate in one direction when the solution in the nucleation tube flows out through the nucleation pores.

[0016] Preferably, the ring is damped when it rotates unidirectionally on the central tube.

[0017] Preferably, the abrasive device includes:

[0018] An annular grinding groove is located on the inner wall of the lower end of the nucleation tube.

[0019] The annular fan rotates at the upper end of the annular grinding groove;

[0020] The grinding cone is concentrically positioned within the annular grinding groove, and its upper end is connected to the center of the annular fan via a column rod.

[0021] Preferably, the stirring device includes:

[0022] The motor is located at the bottom of the processing tank, and its output end is equipped with a rotating shaft that passes through the bottom of the processing tank and the bottom of the screen cylinder.

[0023] The stirring rod is connected to the rotating shaft and is located in the cavity of the sieve cylinder;

[0024] The cleaning frame, connected to the rotating shaft and located in the chamber between the screen cylinder and the treatment tank, cleans the inner walls of the screen cylinder and the treatment tank.

[0025] Preferably, the downpipe 1 of the aerobic tank is connected to the downpipe 1 of the anaerobic tank through the sludge pipe 1, the downpipe 1 of the anoxic tank is connected to the downpipe 1 of the anaerobic tank through the sludge pipe 2, and the lower end of the sedimentation tank is provided with a downpipe 2, which is connected to the downpipe 1 of the anaerobic tank through the sludge pipe 3.

[0026] Preferably, the processing tank is equipped with a temperature control box on its exterior.

[0027] Preferably, the temperature control box is equipped with a visual probe for monitoring suspended particles in the solution inside the treatment tank.

[0028] A wastewater treatment method based on endogenous denitrification for synergistic nitrogen and carbon removal includes the following steps:

[0029] S1: Influent and anaerobic treatment stage. Wastewater enters the anaerobic tank through the central pipe. Under the stirring of the stirring device, it is fully mixed with the activated sludge in the tank to form a mud-water mixture. The mud-water mixture completes the internal carbon source storage reaction in the anaerobic environment. Denitrifying polysaccharide bacteria convert the organic matter in the wastewater into intracellular polymer PHA. The nucleation control device screens the particle size of the dense bacterial community aggregate particles in the anaerobic tank, nucleates and cultivates them, and controls the particle size to maintain the particle size within the target range of 0.8~2.0mm.

[0030] S2: In the aerobic treatment stage, the effluent from the anaerobic tank enters the aerobic tank through the central pipe, and the dissolved oxygen concentration is maintained at 1.5~2.5mg / L. The nucleation control device performs particle size screening, nucleation cultivation, and particle size control on the dense bacterial community aggregate particles in the aerobic tank, maintaining the particle size within the target range of 0.3~1.0mm.

[0031] S3: In the anoxic treatment stage, the effluent from the aerobic tank enters the anoxic tank through the central pipe. The mixing of mud and water is maintained by the stirring device, and the dissolved oxygen concentration is below 0.2 mg / L. Under the anoxic environment, denitrifying polysaccharide bacteria use the PHA stored in their bodies as electron donors to reduce nitrates to nitrogen gas, thus completing endogenous denitrification. The nucleation control device performs particle size screening, nucleation cultivation, and particle size control on the dense bacterial community aggregate particles in the anoxic tank, maintaining the particle size within the target range of 0.5~1.5 mm.

[0032] S4: Sludge-water separation and reflux stage. The sludge-water mixture entering the sedimentation tank is allowed to settle and settle. The supernatant is discharged from the system through the drain pipe, completing the sewage treatment.

[0033] Compared with the prior art, the present invention provides a wastewater synergistic denitrification and carbon removal treatment device and method based on endogenous denitrification, which has the following beneficial effects:

[0034] In this invention, by setting up nucleation control devices in each treatment tank and configuring sieve cylinders with different sieve apertures, rings with different damping, and abrasive devices with different gaps in the anaerobic, aerobic, and anoxic tanks, the differential control of dense bacterial community aggregate particles is achieved. In the anaerobic tank, the particle size is controlled at 0.8~2.0mm. The larger particle size ensures rapid settling and high sludge concentration. At the same time, the strict anaerobic nucleus formed inside the particle provides an ideal microenvironment for PHA synthesis by denitrifying polysaccharide bacteria. In the aerobic tank, the particle size is controlled at 0.3~1.0mm. The small to medium particle size ensures that oxygen can fully diffuse into the particle interior, maximizing the effective working area of ​​nitrifying bacteria. In the anoxic tank, the particle size is controlled at 0.5~1.5mm. The medium particle size can form a stable internal anoxic microzone for endogenous denitrification reaction and ensure effective diffusion and mass transfer of nitrate, so that the internal carbon source storage efficiency, nitrification efficiency, and endogenous denitrification efficiency are simultaneously optimized. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the processing device structure of the present invention;

[0036] Figure 2 This is a schematic diagram of the processing tank structure of the present invention;

[0037] Figure 3 This is a schematic diagram of the nucleation control device of the present invention;

[0038] Figure 4 This is a schematic diagram of the abrasive device structure of the present invention;

[0039] Figure 5 This is a schematic diagram of the nucleation pore structure of the present invention;

[0040] Figure 6 This is a schematic diagram of the stirring device structure of the present invention;

[0041] In the diagram: 1. Treatment tank; 2. Central pipe; 3. Upstream pipe; 4. Downstream pipe one; 5. Discharge pipe; 6. Nucleation control device; 7. Temperature control box; 8. Inlet pipe; 9. Sedimentation tank; 10. Downstream pipe two; 11. Drain pipe; 12. Vision probe; 13. Water guide pipe one; 14. Water guide pipe two; 15. Water guide pipe three; 16. Sludge pipe one; 17. Sludge pipe two; 18. Sludge pipe three; 61. Ring sleeve; 62. Spring; 63. Nucleation pipe; 64. Nucleation hole; 65. Abrasive device; 66. Screen cylinder; 67. Circulation pipe; 68. Circulation pump; 69. Stirring device; 651. Circulating grinding groove; 652. Circulating fan; 653. Column rod; 654. Grinding cone; 691. Motor; 692. Rotating shaft; 693. Stirring rod; 694. Cleaning frame. Detailed Implementation

[0042] Reference Figures 1-6This invention provides a technical solution: a wastewater synergistic denitrification and carbon removal treatment device based on endogenous denitrification, comprising:

[0043] The treatment tank 1 has a central pipe 2 and an upstream pipe 3 at its upper end, and a downstream pipe 4 and a discharge pipe 5 at its lower end. There are three treatment tanks 1 arranged from left to right, namely an anaerobic tank, an aerobic tank and an anoxic tank. The upstream pipe 3 of the anaerobic tank and the central pipe 2 of the aerobic tank are connected by a water guide pipe 13. The upstream pipe 3 of the aerobic tank and the central pipe 2 of the anoxic tank are connected by a water guide pipe 24. The upstream pipe 3 of the anoxic tank is connected to a sedimentation tank 9 through a water guide pipe 35. The sedimentation tank 9 has a drain pipe 11 at its upper end, and the central pipe 2 of the anaerobic tank is connected to an inlet pipe 8.

[0044] The nucleation control device 6 is located in the treatment tank 1 and is used to control the size of the dense bacterial aggregate particles in the anaerobic tank, aerobic tank and anoxic tank.

[0045] The dense microbial community aggregate particles refer to granular aggregates formed by functional microorganisms in activated sludge, including but not limited to denitrifying polysaccharide bacteria (DGAOs) and nitrifying bacteria (AOB / NOB), through self-aggregation. These aggregates have a dense structure, high settling performance, and a specific particle size distribution. These particles are not bacterial balls formed by a single species, nor are they artificially encapsulated microbial agent particles. Instead, they are ecological aggregates naturally formed by multiple functional microbial communities under hydraulic selective pressure. The particles have an oxygen concentration gradient from the outside to the inside, with the outer layer in an aerobic / facultative anaerobic state and the core area maintaining a strictly anaerobic environment, providing differentiated metabolic microenvironments for different functional microbial communities.

[0046] In this embodiment, each treatment tank 1 is equipped with a nucleation control device 6, which is used to differentiate the size of dense bacterial aggregate particles in the anaerobic tank, aerobic tank, and anoxic tank. Specifically, through the nucleation control device 6, the particle size of dense bacterial aggregate particles in the anaerobic tank is controlled at 0.8~2.0mm to maintain a high sludge concentration and a strict anaerobic microenvironment, the particle size of dense bacterial aggregate particles in the aerobic tank is controlled at 0.3~1.0mm to ensure oxygen mass transfer efficiency, and the particle size of dense bacterial aggregate particles in the anoxic tank is controlled at 0.5~1.5mm to form a stable internal anoxic zone.

[0047] In this embodiment, the nucleation control device 6 includes:

[0048] Ring 61 is located on the outer wall of the lower end of the central tube 2 inside the treatment tank 1;

[0049] The nucleating tube 63 has nucleating holes 64 arranged on its side tube wall. Its upper end tube cavity is sleeved outside the lower end of the central tube 2, and its upper end is connected to the ring sleeve 61 by a spring 62.

[0050] The sieve cylinder 66 is located inside the treatment tank 1 and is sleeved outside the nucleation tube 63. Its upper end is fixed to the lower end of the outer wall of the central tube 2, and the lower end of the upflow pipe 3 is connected to the cavity of the sieve cylinder 66. The sieve cylinder 66 is used to retain dense bacterial aggregate particles larger than its sieve holes in its cavity.

[0051] Abrasive device 65 is located in the lower end cavity of nucleation tube 63;

[0052] The lower end of the circulation pipe 67 is connected to the chamber between the screen cylinder 66 and the treatment tank 1, and the upper end is connected to the cavity of the central pipe 2 outside the treatment tank 1. A circulation pump 68 is provided on the pipe.

[0053] A stirring device 69 is located at the bottom of the processing tank 1.

[0054] In other words, the nucleation control device 6 realizes a complete cultivation chain of dense bacterial aggregate particles, including capture, protection, initial growth, screening, grinding, and reflux. The ring 61 is located on the lower outer wall of the central tube 2 inside the treatment tank 1, serving as a suspension and rotation support for the nucleation tube 63. The side wall of the nucleation tube 63 is provided with nucleation holes 64, the upper end of which is sleeved outside the lower end of the central tube 2 and elastically connected to the ring 61 by a spring 62. The spring 62 allows the nucleation tube 63 to vibrate slightly when impacted by water flow, which helps prevent the nucleation holes 64 from becoming blocked. After the mud-water mixture in the central tube 2 enters the nucleation tube 63, it will first be sprayed out through the lower end of the nucleation tube 63, and then flow out through the nucleation holes 64 on the side wall. Therefore, the shearing force through the nucleation holes 64 is small, which is conducive to the nucleation of dense bacterial aggregate particles. The arrangement density and aperture of the nucleation holes 64 are designed differently according to the particle size of the target dense bacterial aggregate particles in each tank.

[0055] In this structure, the sieve cylinder 66 is located inside the treatment tank 1 and is sleeved outside the nucleation tube 63. Its upper end is fixedly connected to the lower outer wall of the central tube 2, and the lower end of the upflow pipe 3 is connected to the cavity of the sieve cylinder 66. This means that only the mud-water mixture that has been screened by the sieve cylinder 66 can flow out from the upflow pipe 3 and enter the next stage treatment tank. The sieve aperture of the sieve cylinder 66 is set according to the target particle size range of each tank - the sieve aperture of the anaerobic tank is about 0.8~1.0mm, the sieve aperture of the aerobic tank is about 0.3~0.5mm, and the sieve aperture of the anoxic tank is about 0.5~0.8mm. The sieve cylinder 66 is used to retain particles larger than its sieve aperture in the cavity to continue to participate in the reaction, while microparticles and liquid smaller than the sieve aperture pass through the sieve aperture and enter the cavity between the sieve cylinder 66 and the treatment tank 1.

[0056] In this structure, the abrasive device 65 is located in the lower end of the nucleation tube 63. When the particles grow to exceed the upper limit of the target particle size, they will be ground by the abrasive device 65 to bring their particle size back to the target range. The lower end of the circulation pipe 67 is connected to the chamber between the screen cylinder 66 and the treatment tank 1, and the upper end is connected to the cavity of the central pipe 2 outside the treatment tank 1. A circulation pump 68 is installed on the pipe. The circulation pump 68 pumps the microparticles and liquid that pass through the screen cylinder 66 back to the central pipe 2 to form an internal circulation, so that the microparticles continue to flow, collide, adhere and grow. The stirring device 69 is located at the bottom of the treatment tank 1 to stir the mud-water mixture in the tank and prevent sludge from settling.

[0057] In this embodiment, the orientation of the nucleation hole 64 is deviated from the axis of the nucleation tube 63, and the ring 61 is unidirectionally rotatable on the central tube 2. When the solution in the nucleation tube 63 flows out through the nucleation hole 64, the ring 61 can rotate unidirectionally.

[0058] In other words, to simultaneously achieve low-shear nucleation protection and prevent the adhesion of dense bacterial aggregate particles to its outer wall, the orientation of the nucleation pore 64 is deviated from the axis of the nucleation tube 63, i.e., it is tangential or obliquely open. When the mud-water mixture flows out of the nucleation tube 63 through the nucleation pore 64, it forms a rotating jet rather than a radial straight jet. When the circulating pump 68 is driven at a constant speed and low speed, it will cause the nucleation tube 63 to rotate slowly. At the same time, the solution in the lumen of the nucleation tube 63 will preferentially flow towards its lower end. At this time, the nucleation pore 64 can exhibit a slow flow, which is conducive to the formation of dense bacterial aggregate particles. As the cells grow, the openings of the nucleation pores gradually decrease. At this point, the blockage of the nucleation pore openings can be judged by the rotation speed of the annular fan. If the rotation speed of the annular fan increases significantly, the liquid flow at the nucleation pore openings is poor. The dense bacterial aggregate particles have grown to a certain size. Therefore, the circulation pump 68 is driven in a short and variable speed mode. The annular fan can generate a certain amount of resistance, causing the nucleation pores to be impacted, thereby discharging the completed dense bacterial aggregate particles. After this is completed, the circulation pump returns to a low and uniform speed driving mode to continue the growth and cultivation of dense bacterial aggregate particles.

[0059] In this embodiment, when the ring 61 rotates unidirectionally on the central tube 2, it is damped. That is, by setting the damping, the rotation speed of the nucleation tube 63 is reduced to avoid damaging the growing microparticles. The damping makes the rotation of the nucleation tube 63 more stable, avoiding instability caused by rotation speed fluctuations, and providing a stable hydraulic environment for particle nucleation and screening.

[0060] In this embodiment, the abrasive device 65 includes:

[0061] An annular grinding groove 651 is provided on the inner wall of the lower end of the nucleation tube 63;

[0062] The annular fan 652 rotates at the upper end of the annular grinding groove 651;

[0063] The grinding cone 654 is concentrically located in the annular grinding groove 651, and its upper end is connected to the center of the annular fan 652 through the column rod 653.

[0064] The annular grinding groove 651 is located on the inner wall of the lower end of the nucleation tube 63 and is an annular groove structure. When the particles grow to exceed the upper limit of the target particle size, they will be ground by the grinding cone 654. The annular fan 652 is rotatably installed on the upper end of the annular grinding groove 651 with its blades facing the direction of water flow. When the mud-water mixture flows out from the lower end of the nucleation tube 63, the water flow pushes the annular fan 652 to rotate. The grinding cone 654 is concentrically located in the annular grinding groove 651 and its upper end is connected to the center of the annular fan 652 through the column rod 653. When the annular fan 652 is pushed to rotate by the water flow, it drives the grinding cone 654 to rotate synchronously through the column rod 653. The oversized particles that enter the annular grinding groove 651 are ground in the gap between the grinding cone 654 and the inner wall of the annular grinding groove 651. The loose surface structure is ground off and the particle size gradually decreases until it can leave the annular grinding groove 651 with the water flow.

[0065] The size of the gap between the grinding cone 654 and the inner wall of the ring grinding groove 651 determines the grinding intensity. By replacing the grinding cone 654 with different tapers, the grinding intensity can be adjusted. Different abrasive devices 65 with different gaps can be set in different treatment tanks 1. The anaerobic tank has the largest target particle size and the gap is set to be larger. The aerobic tank has the smallest target particle size and the gap is set to be smaller. The anoxic tank has a medium target particle size and the gap is set to be medium.

[0066] In this embodiment, the stirring device 69 includes:

[0067] The motor 691 is located at the bottom of the processing tank 1, and a rotating shaft 692 is installed at its output end. The rotating shaft 692 passes through the bottom of the processing tank 1 and the bottom of the screen cylinder 66.

[0068] The stirring rod 693 is connected to the rotating shaft 692 and is located in the cavity of the sieve cylinder 66;

[0069] The cleaning frame 694 is connected to the rotating shaft 692 and is located in the chamber between the screen cylinder 66 and the processing tank 1, and cleans the inner wall of the screen cylinder 66 and the processing tank 1.

[0070] Among them, the motor 691 is located at the bottom of the treatment tank 1 and adopts a variable frequency speed control motor. The speed can be adjusted according to the stirring requirements of each tank. The anaerobic tank and the anoxic tank need to maintain the sludge suspension and adopt low-speed stirring. The aerobic tank mainly achieves mixing through aeration. The stirring device can operate at low speed or intermittently. The stirring rod 693 is connected to the rotating shaft 692 and is located in the cavity of the screen cylinder 66. It is used to stir the mud-water mixture in the screen cylinder 66 to prevent particle deposition and promote full contact between particles and substrate. In the anaerobic tank and the anoxic tank, the stirring of the stirring rod 693 also causes the nitrogen microbubbles generated by denitrification to desorb from the particle surface, preventing the particles from floating and being lost due to the adhesion of bubbles.

[0071] The cleaning frame 694 is connected to the rotating shaft 692 and is located in the chamber between the screen cylinder 66 and the processing tank 1. It has a frame structure that matches the shape of the outer wall of the screen cylinder 66 and the inner wall of the processing tank 1. Brushes or scrapers can be installed on the surface. Driven by the rotating shaft 692, the cleaning frame 694 continuously cleans the outer wall of the screen cylinder 66 and the inner wall of the processing tank 1, effectively preventing the screen holes from being blocked and the tank walls from accumulating mud. This ensures the long-term stability of the screening function and eliminates the maintenance workload of manual disassembly and cleaning.

[0072] In this embodiment, the downpipe 4 of the aerobic tank is connected to the downpipe 4 of the anaerobic tank through the sludge pipe 16, the downpipe 4 of the anoxic tank is connected to the downpipe 4 of the anaerobic tank through the sludge pipe 2 17, and the sedimentation tank 9 is provided with a downpipe 2 10 at the lower end, which is connected to the downpipe 4 of the anaerobic tank through the sludge pipe 3 18.

[0073] Among them, the downflow pipe 4 of the aerobic tank is connected to the downflow pipe 4 of the anaerobic tank through the sludge pipe 16. Some particles deposited at the bottom of the aerobic tank are returned to the front end of the anaerobic tank through this path. These particles have just undergone nitrification and their PHA has not yet been consumed. The nitrifying bacteria attached to them are in an active state. After being returned, they can replenish the nitrifying bacteria source for the system.

[0074] Among them, the downflow pipe 4 of the anoxic tank is connected to the downflow pipe 4 of the anaerobic tank through the sludge pipe 17. Some particles deposited at the bottom of the anoxic tank are returned to the front end of the anaerobic tank through this path. These particles have just completed endogenous denitrification and the PHA stored in them has been basically depleted. They are in a "starved" state. Starved denitrifying polysaccharide bacteria have the strongest ability to take up organic matter in the influent and the highest PHA synthesis rate. Sending these particles directly back to the front end of the anaerobic tank allows them to come into contact with the fresh carbon source in the influent as soon as possible, which can maximize the internal carbon source storage efficiency and ensure the closure of the "starvation-fullness" metabolic cycle of denitrifying polysaccharide bacteria.

[0075] The sedimentation tank 9 is equipped with a second downflow pipe 10 at the lower end. The second downflow pipe 10 is connected to the first downflow pipe 4 of the anaerobic tank through a third sludge pipe 18. The concentrated sludge settled at the bottom of the sedimentation tank 9 is returned to the front end of the anaerobic tank through this path to maintain the overall sludge concentration. Each sludge pipe is equipped with a return pump, which can independently adjust the flow ratio of each loop to achieve optimal microbial community allocation.

[0076] In this embodiment, a temperature control box 7 is provided outside the processing tank 1. The temperature control box 7 surrounds the outer wall of the processing tank 1 and maintains the temperature inside the processing tank 1 within a suitable range of 15~35℃ through heat exchange.

[0077] Among them, the ability of microorganisms to secrete extracellular polymers is strongest at 20~30℃, resulting in the best particle density and sedimentation performance; below 15℃, the secretion of extracellular polymers decreases, the particle structure becomes loose, and the granulation time is significantly prolonged. The nitrification reaction in the aerobic tank is the most sensitive to temperature, so a higher temperature of 25~30℃ is set; the anaerobic and anoxic tanks are set at a slightly lower temperature of 20~25℃ to save heating energy.

[0078] In this embodiment, the temperature control box 7 is equipped with a visual probe 12 for monitoring suspended particles in the solution inside the processing tank 1.

[0079] The vision probe 12 captures images of suspended particles inside the tank at a certain frequency. Through image processing algorithms, it identifies particle outlines, statistically analyzes particle size distribution, and automatically calculates parameters such as average particle size, median particle size, and particle size distribution span. At the same time, the vision probe 12 can identify morphological parameters such as particle roundness, density, and edge sharpness. Densely structured particles are regular spherical with clear outlines, while loose flocs have irregular shapes and blurred edges. By analyzing the number and distribution density of particles in the image, the sludge concentration inside the tank can also be estimated, which can then be fed back to the circulation pump and motor for adjustment.

[0080] In its specific implementation, it includes the following steps:

[0081] S1: In the influent and anaerobic treatment stage, the wastewater enters the anaerobic tank through the central pipe 2. Under the stirring of the stirring device 69, it is fully mixed with the activated sludge in the tank to form a mud-water mixture. The mud-water mixture completes the internal carbon source storage reaction in the anaerobic environment. Denitrifying polysaccharide bacteria convert the organic matter in the wastewater into intracellular polymer PHA. The nucleation control device 6 performs particle size screening, nucleation cultivation and particle size control on the dense bacterial community aggregate particles in the anaerobic tank to maintain the particle size within the target range of 0.8~2.0mm.

[0082] Stirring maintains sludge suspension, dissolved oxygen is strictly controlled below 0.1 mg / L, and the sludge-water mixture completes the internal carbon source storage reaction under anaerobic conditions. Denitrifying polysaccharide bacteria utilize volatile fatty acids in wastewater to synthesize and store PHA in their bodies, resulting in a significant decrease in COD concentration in wastewater and a relatively unchanged ammonia nitrogen concentration. The sieve cylinder 66 retains particles larger than the sieve holes in the cylinder cavity, the abrasive device 65 grinds the excessively large particles, and the circulating pump 68 pumps the micro-particles back to the central pipe 2 to continue circulating and growing. Through the above synergistic effect, the particle size in the anaerobic tank is stably maintained within the target range of 0.8~2.0 mm.

[0083] S2: In the aerobic treatment stage, the effluent from the anaerobic tank enters the aerobic tank through the central pipe 2, and the dissolved oxygen concentration is maintained at 1.5~2.5mg / L. The nucleation control device 6 performs particle size screening, nucleation cultivation, and particle size control on the dense bacterial aggregate particles in the aerobic tank, maintaining the particle size within the target range of 0.3~1.0mm. This particle size range can ensure that oxygen can be fully diffused into the interior of the particles to maximize the working area of ​​nitrifying bacteria, while preventing loss due to excessively small particles.

[0084] S3: In the anoxic treatment stage, the effluent from the aerobic tank enters the anoxic tank through the central pipe 2. The mixing of mud and water is maintained by the stirring device 69, and the dissolved oxygen concentration is below 0.2 mg / L. Under the anoxic environment, denitrifying polysaccharide bacteria use the PHA stored in their bodies as electron donors to reduce nitrates to nitrogen gas, completing endogenous denitrification. The nucleation control device 6 performs particle size screening, nucleation cultivation, and particle size control on the dense bacterial community aggregate particles in the anoxic tank, maintaining the particle size within the target range of 0.5~1.5 mm. This particle size range can form a stable internal anoxic microzone for denitrification reaction and ensure effective diffusion and mass transfer of nitrates. The anoxic tank adopts a low-shear plug flow environment, which can maintain particle suspension and matrix mass transfer, and avoid particle breakage caused by strong shear.

[0085] S4: Sludge-water separation and reflux stage. The sludge-water mixture entering the sedimentation tank 9 is allowed to settle and settle. The supernatant is discharged from the system through the drain pipe 11, completing the sewage treatment.

[0086] During operation, the temperature inside each processing tank is maintained within the range of 15~35℃ by the temperature control box 7. The vision probe 12 monitors the particle size distribution and morphological characteristics of the particles inside the tank in real time. When the particle size is detected to be outside the target range, the flow rate of the circulation pump 68 and / or the working parameters of the abrasive device 65 are automatically adjusted to restore the particle size to the target range.

[0087] The above description is merely a preferred embodiment of the invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A wastewater treatment device for synergistic denitrification and carbon removal based on endogenous denitrification, characterized in that, It includes: The treatment tank (1) is provided with a central pipe (2) and an upstream pipe (3) at its upper end, and a downstream pipe (4) and a discharge pipe (5) at its lower end. The treatment tank (1) is provided with three pipes from left to right, namely an anaerobic tank, an aerobic tank and an anoxic tank. The upstream pipe (3) of the anaerobic tank and the central pipe (2) of the aerobic tank are connected by a water guide pipe (13). The upstream pipe (3) of the aerobic tank and the central pipe (2) of the anoxic tank are connected by a water guide pipe (2) (14). The upstream pipe (3) of the anoxic tank is connected to a sedimentation tank (9) through a water guide pipe (3) (15). The sedimentation tank (9) is provided with a drain pipe (11) at its upper end, and the central pipe (2) of the anaerobic tank is connected to an inlet pipe (8). The nucleation control device (6) is located in the treatment tank (1) and is used to control the size of the dense bacterial aggregate particles in the anaerobic tank, aerobic tank and anoxic tank.

2. The wastewater co-treatment device for nitrogen and carbon removal based on endogenous denitrification according to claim 1, characterized in that, The nucleation control device (6) includes: A ring (61) is provided on the outer wall of the lower end of the central tube (2) inside the treatment tank (1); The nucleating tube (63) has nucleating holes (64) arranged on its side wall. Its upper end is sleeved outside the lower end of the central tube (2), and its upper end is connected to the ring (61) by a spring (62). The sieve cylinder (66) is located inside the treatment tank (1) and is fitted outside the nucleation tube (63). Its upper end is fixed to the lower outer wall of the central tube (2), and the lower end of the upstream pipe (3) is connected to the cavity of the sieve cylinder (66). The sieve cylinder (66) is used to retain dense bacterial aggregate particles larger than its sieve holes in its cavity. Abrasive device (65) is located in the lower end cavity of nucleation tube (63); The circulation pipe (67) is connected at its lower end to the chamber between the screen cylinder (66) and the treatment tank (1), and at its upper end to the cavity of the central pipe (2) outside the treatment tank (1), and is equipped with a circulation pump (68). A stirring device (69) is located at the bottom of the processing tank (1).

3. The wastewater co-treatment device for nitrogen and carbon removal based on endogenous denitrification according to claim 2, characterized in that, The orientation of the nucleation hole (64) is offset from the axis of the nucleation tube (63), and the ring (61) is unidirectionally rotatable on the central tube (2). When the solution in the nucleation tube (63) flows out through the nucleation hole (64), the ring (61) can rotate unidirectionally.

4. The wastewater co-treatment device for nitrogen and carbon removal based on endogenous denitrification according to claim 3, characterized in that, The ring (61) is damped when it rotates unidirectionally on the central tube (2).

5. A wastewater co-treatment device for nitrogen and carbon removal based on endogenous denitrification according to claim 3, characterized in that, The abrasive device (65) includes: The annular grinding groove (651) is located on the inner wall of the lower end of the nucleation tube (63); The ring fan (652) rotates at the upper end of the ring grinding groove (651); The grinding cone (654) is concentrically located in the annular grinding groove (651), and its upper end is connected to the center of the annular fan (652) through the column rod (653).

6. The wastewater co-denitrification and carbon removal treatment device based on endogenous denitrification according to claim 5, characterized in that, The stirring device (69) includes: The motor (691) is located at the bottom of the processing tank (1), and a rotating shaft (692) is installed at its output end. The rotating shaft (692) passes through the bottom of the processing tank (1) and the bottom of the screen cylinder (66). A stirring rod (693) is connected to a rotating shaft (692) and located in the cavity of a sieve cylinder (66); A cleaning frame (694) is connected to a rotating shaft (692) and located in a chamber between a screen cylinder (66) and a treatment tank (1) to clean the inner walls of the screen cylinder (66) and the treatment tank (1).

7. The wastewater co-treatment device for nitrogen and carbon removal based on endogenous denitrification according to claim 1, characterized in that, The downpipe 1 (4) of the aerobic tank is connected to the downpipe 1 (4) of the anaerobic tank through the sludge pipe 1 (16). The downpipe 1 (4) of the anoxic tank is connected to the downpipe 1 (4) of the anaerobic tank through the sludge pipe 2 (17). The sedimentation tank (9) is provided with a downpipe 2 (10) at the lower end. The downpipe 2 (10) is connected to the downpipe 1 (4) of the anaerobic tank through the sludge pipe 3 (18).

8. The wastewater co-treatment device for nitrogen and carbon removal based on endogenous denitrification according to claim 1, characterized in that, The processing tank (1) is equipped with a temperature control box (7) on the outside.

9. A wastewater co-treatment device for nitrogen and carbon removal based on endogenous denitrification according to claim 8, characterized in that, The temperature control box (7) is equipped with a visual probe (12) for monitoring suspended particles in the solution inside the treatment tank (1).

10. A wastewater co-treatment method for nitrogen and carbon removal based on endogenous denitrification, comprising using a wastewater co-treatment device for nitrogen and carbon removal based on endogenous denitrification as described in any one of claims 2-9, characterized in that, It includes the following steps: S1: In the influent and anaerobic treatment stage, the sewage enters the anaerobic tank through the central pipe (2). Under the stirring of the stirring device (69), it is fully mixed with the activated sludge in the tank to form a mud-water mixture. The mud-water mixture completes the internal carbon source storage reaction in the anaerobic environment. The denitrifying polysaccharide bacteria convert the organic matter in the sewage into intracellular polymer PHA. The nucleation control device (6) performs particle size screening, nucleation cultivation and particle size control on the dense bacterial community aggregate particles in the anaerobic tank to maintain the particle size within the target range of 0.8~2.0mm. S2: In the aerobic treatment stage, the effluent from the anaerobic tank enters the aerobic tank through the central pipe (2), and the dissolved oxygen concentration is maintained at 1.5~2.5mg / L. The nucleation control device (6) performs particle size screening, nucleation cultivation, and particle size control on the dense bacterial aggregate particles in the aerobic tank, maintaining the particle size within the target range of 0.3~1.0mm. S3: During the anoxic treatment stage, the effluent from the aerobic tank enters the anoxic tank through the central pipe (2). The mixing of mud and water is maintained by the stirring device (69), and the dissolved oxygen concentration is lower than 0.2 mg / L. Under the anoxic environment, the denitrifying polysaccharide bacteria use the PHA stored in their bodies as electron donors to reduce nitrates to nitrogen gas, thus completing the endogenous denitrification. The nucleation control device (6) performs particle size screening, nucleation cultivation, and particle size control on the dense bacterial community aggregate particles in the anoxic tank, maintaining the particle size within the target range of 0.5~1.5 mm. S4: Sludge-water separation and reflux stage. The sludge-water mixture entering the sedimentation tank (9) is allowed to settle and settle. The supernatant is discharged from the system through the drain pipe (11) to complete the sewage treatment.

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