Aerobic granular sludge treatment device for efficiently removing nitrogen and phosphorus from sewage with low carbon nitrogen ratio

Abstract

The invention discloses an aerobic granular sludge treatment device for efficient nitrogen and phosphorus removal of sewage with a low carbon-nitrogen ratio. The aerobic granular sludge treatment device comprises a reaction zone; the sludge hydrolysis area and the reaction area share the pool wall and are arranged in parallel; the water inlet main pipe is communicated with the reaction area and is used for supplying sewage into the reaction area; two ends of the return pipe are respectively communicated with the sludge hydrolysis area and the water inlet main pipe, and the return pipe is used for feeding sludge in the sludge hydrolysis area into the water inlet main pipe, and the sludge enters the reaction area along with sewage; two ends of the sludge conveying pipe are respectively communicated with the bottoms of the sludge hydrolysis area and the reaction area, and the sludge conveying pipe is used for conveying sludge at the bottom of the reaction area into the sludge hydrolysis area. The invention has the following beneficial effects: rapid formation of aerobic granular sludge can be realized, and sewage treatment and sludge anaerobic hydrolysis fermentation can be synchronously realized through spatial configuration combination of the tank body; volatile fatty acid generated by sludge hydrolysis and fermentation can improve the concentration of biodegradable organic matters in the reaction device, so that the nitrogen and phosphorus removal efficiency of biological treatment is improved, and meanwhile, the yield of residual sludge is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, in particular to an aerobic granular sludge treatment device for efficiently removing nitrogen and phosphorus from low carbon-nitrogen ratio sewage. Background Art

[0002] At present, a large number of urban sewage collection and treatment systems have been built in various cities in my country. Due to the poor quality of pipeline construction, long-term inadequate operation and maintenance, many cities have problems such as pipe siltation, sewage infiltration, and intrusion of external water such as industrial water and surface water, resulting in low influent concentration of terminal sewage treatment plants. At the same time, there is also a common imbalance between the ratio of carbon source and nutrients. It is expected that these drainage network problems will not be fundamentally improved in the long term. At present, most urban sewage treatment plants use biological phosphorus removal and nitrogen removal processes. Since the microbial nitrogen and phosphorus removal process requires the use of organic matter in sewage, the low influent concentration of sewage and the low ratio of carbon source and nutrients will seriously affect the efficiency of biological nitrogen and phosphorus removal. Therefore, in order to meet the effluent specification indicators, sewage treatment plants often need to add a large amount of chemical agents and increase the aeration volume of biological treatment tanks, thereby increasing operating costs and increasing sludge production.

[0003] With the proposal of my country's "dual carbon" goals, a strong signal for the resource, energy and low-carbon development of my country's wastewater has been released at the national strategic level. Wastewater carbon reduction actions have become imperative in various regions. Carrying out research on wastewater carbon neutrality technology has become an inevitable requirement for the development of my country's water affairs in the new era and new stage. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and to propose an aerobic granular sludge treatment device for efficient denitrification and phosphorus removal from low carbon-nitrogen ratio sewage, which can not only realize the rapid formation of aerobic granular sludge, but also simultaneously realize sewage treatment and sludge hydrolysis and fermentation through the spatial configuration combination of the pool body. The volatile fatty acids produced by sludge hydrolysis and fermentation can increase the concentration of biodegradable organic matter in the reaction device, thereby improving the denitrification and phosphorus removal efficiency of biological treatment.

[0005] The object of the present invention is achieved through the following technical scheme: an aerobic granular sludge treatment device for efficiently removing nitrogen and phosphorus from low carbon-nitrogen ratio sewage, comprising: Reaction zone; A sludge hydrolysis zone is disposed adjacent to the common pool wall of the reaction zone; A water inlet main pipe is connected to the reaction zone and is used to supply sewage into the reaction zone; A reflux pipe, both ends of which are connected to the sludge hydrolysis zone and the water inlet pipe respectively, and is used to send the sludge in the sludge hydrolysis zone into the water inlet pipe, and the sludge enters the reaction zone together with the sewage; The two ends of the sludge conveying pipe are respectively connected to the bottom of the sludge hydrolysis zone and the reaction zone, and are used to convey the sludge at the bottom of the reaction zone into the sludge hydrolysis zone.

[0006] A mud discharge device is arranged in the reaction zone, a mud discharge pipe is connected to the mud discharge device, and a mud discharge valve is arranged on the mud discharge pipe.

[0007] A water distribution device is provided at the bottom of the reaction zone, and the water distribution device is communicated with the water inlet main pipe.

[0008] An aeration device is arranged in the reaction zone, an air supply pipe is connected to the aeration device, and a blower is connected to one end of the air supply pipe away from the aeration device.

[0009] A water collecting tank is arranged on the top of the reaction zone, and a water outlet pipe is arranged in communication with the water collecting tank.

[0010] The sludge hydrolysis zone is provided with a stirring device, and the stirring device is connected to a stirring motor for driving the stirring device to work.

[0011] The water inlet main pipe is provided with a water inlet pump and a liquid flow meter.

[0012] The reflux pipe is provided with a reflux pump.

[0013] The mud conveying pipe is provided with an electric valve and a vent pipe.

[0014] A multi-bucket sludge discharge structure is arranged at the bottom of the sludge hydrolysis zone.

[0015] The beneficial effects of the present invention are: (1) The present invention combines sludge hydrolysis with aerobic granular sludge, and transports the sludge at the bottom of the reaction zone to the sludge hydrolysis zone through the liquid level difference for sludge hydrolysis and fermentation, and uses a reflux pump to return the mixed liquid from the sludge hydrolysis zone to the reaction zone to supplement the carbon source of the influent. It is suitable for urban sewage with a low carbon-nitrogen ratio, improves the phosphorus and nitrogen removal efficiency, and at the same time maintains the activity of the granular sludge and achieves a certain degree of sludge reduction.

[0016] (2) The present invention utilizes left and right partitions to separate the sludge hydrolysis zone from the reaction zone, thereby avoiding the impact of oxygenation during the aeration stage on the anaerobic environment of the sludge hydrolysis zone, achieving efficient pollutant removal, and effectively realizing the efficiency of biological functional zoning. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the present invention; Figure numerals: 1. water inlet main pipe; 2. water inlet pump; 3. liquid flow meter; 4. water distribution device; 5. aeration device; 6. air supply pipe; 7. fan; 8. sludge discharge device; 9. sludge discharge valve; 10. sludge discharge pipe; 11. water outlet pipe; 12 water collecting tank; 13. stirring motor; 14. stirring device; 15. reflux pipe; 16. reflux pump; 17. sludge transport pipe; 18. ventilation pipe; 19. electric valve; 20. sludge hydrolysis zone; 21. reaction zone; 22. multi-bucket sludge discharge structure. DETAILED DESCRIPTION

[0018] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0019] It is to be noted that the concepts of directions “left”, “right”, “up”, “down”, “front”, “back”, “inside” and “outside” in the following schemes are all relative directions and are not listed one by one here.

[0020] An aerobic granular sludge treatment device for efficient nitrogen and phosphorus removal from low carbon-nitrogen ratio sewage, reference Figure 1 , including a reaction zone 21 and a sludge hydrolysis zone 20 arranged side by side on the left and right. The reaction zone 21 and the sludge hydrolysis zone 20 share a pool wall and are arranged adjacent to each other. A water inlet pipe 1 is connected to the bottom of the reaction zone 21. A water inlet pump 2 and a liquid flow meter 3 are arranged on the water inlet pipe 1. A multi-bucket sludge discharge structure 22 is arranged at the bottom of the sludge hydrolysis zone 20. A reflux pipe 15 is connected to the bottom of the sludge hydrolysis zone 20, and the other end of the reflux pipe 15 is connected to the water inlet pipe 1. A reflux pump 16 is arranged on the reflux pipe 15.

[0021] A water collecting tank 12 is provided at the top of the reaction zone 21. The water collecting tank 12 is opened by a triangular weir. The end of the water collecting tank 12 is connected to a water outlet pipe 11. A water distribution device 4 is provided at the bottom of the reaction zone 21. The water distribution device 4 is connected to the water inlet main pipe 1. An aeration device 5 is also provided at the bottom of the reaction zone 21. The aeration device 5 is connected to an air supply pipe 6, and a fan 7 is connected to the end of the air supply pipe 6. A mud discharge device 8 is provided at the top of the reaction zone 21. The mud discharge device 8 is connected to a mud discharge pipe 10, and the end of the mud discharge pipe 10 away from the mud discharge device 8 is located outside the reaction zone 21. A mud discharge valve 9 is provided on the mud discharge pipe 10.

[0022] A stirring device 14 is provided in the sludge hydrolysis zone 20. A stirring motor 13 for driving the stirring device 14 is provided at the upper end thereof. A mud delivery pipe 17 is provided between the reaction zone 21 and the sludge hydrolysis zone 20. One end of the mud delivery pipe 17 is connected to the bottom of the reaction zone 21, and the other end is connected to the upper part of the sludge hydrolysis zone 20. An electric valve 19 is provided on the mud delivery pipe 17.

[0023] Inlet / outlet stage: start the reflux pump 16 and the inlet pump 2, and send the mud-water mixture at the bottom of the sludge hydrolysis zone 20 into the inlet main pipe 1 through the reflux pump 16. The inlet pump 2 mixes the sewage and the mud-water mixture evenly and slowly and continuously into the reaction zone 21, thereby replenishing the inlet carbon source. The sewage flows from the bottom to the top in a piston flow, and the top of the device is supported and discharged into the sump 12. The drainage ratio is controlled at 40%~60%. At this ratio, the sewage inlet cannot penetrate the sludge layer to the top sump 12. The sludge in the reaction zone 21 absorbs and internalizes the biodegradable organic matter in the inlet water and the reflux liquid of the sludge hydrolysis zone 20 into internal carbon source substances (PHA), and the sludge undergoes anaerobic phosphorus release reaction. .

[0024] Aeration stage: The aeration device 5 is started to provide sufficient dissolved oxygen and hydraulic shear force to flush the sludge, promote the collision and coagulation of the flocculent sludge in the reaction zone 21, and accelerate the secretion of a large amount of extracellular polymers by the sludge to accelerate the granulation process. In the early stage of aeration, the total phosphorus concentration in the reaction zone 21 increases temporarily due to the anaerobic phosphorus release of the sludge. In the aeration stage, due to the layered structure of aeration and aerobic granular sludge (external aerobic layer, middle facultative anoxic layer, internal anaerobic layer), organic matter removal and nitrification reaction, endogenous denitrification and phosphorus removal reaction occur in the reaction zone 21, and the sludge degrades organic matter into carbon dioxide and water, and degrades total nitrogen substances into nitrogen. , , .

[0025] Sedimentation / sludge discharge stage: turn off the fan 7 and the aeration device 5, and the reaction zone 21 enters the sedimentation state. At the end of the sedimentation, the sludge discharge valve 9 is opened, and the upper lighter flocculent sludge is discharged from the reaction zone 21 through the sludge discharge device 8 under the action of the sedimentation selection pressure. The heavier granular sludge is retained in the reaction zone 21. Repeatedly, under the action of hydraulic shear force and sedimentation selection pressure, the formation of aerobic granular sludge is promoted. At the same time, the electric valve 19 on the sludge pipe 17 is opened, and the sludge at the bottom of the reaction zone 21 is discharged into the sludge hydrolysis zone 20 under the action of water pressure (4~10% of the sludge amount in the pool), and the HRT in the sludge hydrolysis zone 20 is 30~72h. In the sedimentation stage, the sludge further undergoes denitrification.

[0026] After sedimentation is completed, the next cycle of anaerobic inlet / outlet phase begins.

[0027] The stirring device of the sludge hydrolysis zone 20 is continuously operated at a low speed to ensure that the area is fully mixed. Under anaerobic conditions, the sludge is endogenously consumed to produce volatile organic acids, and the sludge can be effectively reduced. .

[0028] The effective water depth of the reaction zone 21 is about 6-10 m, and the effective water depth of the sludge hydrolysis zone 20 is about 4-8 m. The width ratio of the reaction zone 21 to the sludge hydrolysis zone 20 is adjusted according to actual operation.

[0029] The present invention achieves wastewater treatment and sludge reduction simultaneously through zoning design. While the reaction zone 21 is performing denitrification and dephosphorization, the sludge hydrolysis zone 20 is performing sludge hydrolysis and fermentation, and the generated volatile fatty acids (VFA) are directly used as an organic carbon source in the biological denitrification and dephosphorization process of the reaction zone. The present invention is suitable for the treatment of urban wastewater with a low C / N ratio, effectively reducing the addition of additional carbon sources, while promoting efficient recovery and reuse of resources.

[0030] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above description or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. An aerobic granular sludge treatment device for efficient nitrogen and phosphorus removal from low carbon-nitrogen ratio sewage, characterized in that: include: Reaction zone; The sludge hydrolysis zone is not connected to the reaction zone and is isolated from each other; A water inlet main pipe is connected to the reaction zone and is used to supply sewage into the reaction zone; A reflux pipe, both ends of which are connected to the sludge hydrolysis zone and the water inlet pipe respectively, and is used to send the sludge in the sludge hydrolysis zone into the water inlet pipe, and the sludge enters the reaction zone together with the sewage; The two ends of the sludge conveying pipe are respectively connected to the bottom of the sludge hydrolysis zone and the reaction zone, and are used to convey the sludge at the bottom of the reaction zone into the sludge hydrolysis zone.

2. The aerobic granular sludge treatment device for high-efficiency nitrogen and phosphorus removal of low carbon-nitrogen ratio sewage according to claim 1 is characterized by: A mud discharge device is arranged in the reaction zone, a mud discharge pipe is connected to the mud discharge device, and a mud discharge valve is arranged on the mud discharge pipe.

3. The aerobic granular sludge treatment device for high-efficiency nitrogen and phosphorus removal of low carbon-nitrogen ratio sewage according to claim 1 is characterized by: A water distribution device is provided at the bottom of the reaction zone, and the water distribution device is communicated with the water inlet main pipe.

4. The aerobic granular sludge treatment device for high-efficiency nitrogen and phosphorus removal of low carbon-nitrogen ratio sewage according to claim 1 is characterized by: An aeration device is arranged in the reaction zone, an air supply pipe is connected to the aeration device, and a blower is connected to one end of the air supply pipe away from the aeration device.

5. The aerobic granular sludge treatment device for high-efficiency nitrogen and phosphorus removal of low carbon-nitrogen ratio sewage according to claim 1 is characterized by: A water collecting tank is arranged on the top of the reaction zone, and a water outlet pipe is arranged in communication with the water collecting tank.

6. The aerobic granular sludge treatment device for high-efficiency nitrogen and phosphorus removal of low carbon-nitrogen ratio sewage according to claim 1 is characterized by: The sludge hydrolysis zone is provided with a stirring device, and the stirring device is connected to a stirring motor for driving the stirring device to work.

7. The aerobic granular sludge treatment device for high-efficiency nitrogen and phosphorus removal of low carbon-nitrogen ratio sewage according to claim 1 is characterized by: The water inlet main pipe is provided with a water inlet pump and a liquid flow meter.

8. The aerobic granular sludge treatment device for high-efficiency nitrogen and phosphorus removal of low carbon-nitrogen ratio sewage according to claim 1 is characterized by: The reflux pipe is provided with a reflux pump.

9. The aerobic granular sludge treatment device for high-efficiency nitrogen and phosphorus removal of low carbon-nitrogen ratio sewage according to claim 1 is characterized by: The mud conveying pipe is provided with an electric valve and a vent pipe.

10. The aerobic granular sludge treatment device for high-efficiency nitrogen and phosphorus removal of low carbon-nitrogen ratio sewage according to claim 1, characterized in that: A multi-bucket sludge discharge structure is arranged at the bottom of the sludge hydrolysis zone.

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