Nested short-cut denitrification clarification tank

Abstract

An equipment room is arranged on the lower portion of a main tank body, a solid-liquid separation tank, a water distribution ring and a denitrification reaction ring are sequentially arranged on the upper portion of the main tank body from inside to outside, and the denitrification reaction ring comprises a first denitrification tank, a second denitrification tank, a first dosing tank and a second dosing tank which are sequentially communicated. A water inlet pipe is arranged at the input end of the first denitrification tank, the second dosing tank is communicated with the water distribution ring, a sludge settling zone, a water distribution zone, an inclined tube filler layer and a clear water zone are sequentially formed in the solid-liquid separation tank from bottom to top, the water distribution zone is communicated with the water distribution ring, the clear water zone is provided with a drain pipe assembly, and a sludge hopper is arranged on the lower side of the sludge settling zone. A sludge discharge pump and a sludge reflux pump are arranged in the equipment room, and the sludge discharge pump and the sludge reflux pump are respectively communicated with the sludge bucket through corresponding pipelines. The device disclosed by the utility model is more compact in overall structure, so that the occupied area of equipment is reduced, the use of a carbon source is reduced, the reaction time is shortened, and the sludge yield is reduced.

Description

Technical Field

[0001] The utility model relates to the field of sewage treatment, in particular to a nested short-range denitrification clarification tank. Background Art

[0002] For high-ammonia nitrogen wastewater with large fluctuations in water quality, ammonia nitrogen and total nitrogen that do not meet standards often appear at the end of sewage treatment. In order to ensure that the pollutant indicators at the end of sewage treatment can be 100% discharged in compliance with standards, the existing technology will add an ammonia nitrogen / total nitrogen deep treatment device at the end of the treatment during construction of the sewage treatment plant, or for sewage treatment plants that have been built for many years, a set of ammonia nitrogen / total nitrogen deep treatment equipment can be added at the end of the sewage treatment. This will not change the tank structure of the original sewage plant, thereby reducing the transformation cost.

[0003] Traditional methods for deep treatment of ammonia nitrogen / total nitrogen include physical methods, chemical methods, biological methods, etc. Among them, the physical method mainly uses an ammonia removal tower, but this technology has the problem of generating free ammonia and causing secondary pollution, and also has the disadvantages of using quicklime to easily cause scale, and the water temperature is reduced, resulting in reduced denitrification effect. The chemical method mostly involves adding ammonia nitrogen removal agents, but this method is relatively expensive. The biological method utilizes the joint action of nitrifying bacteria and denitrifying bacteria, including activated sludge denitrification, biological denitrification filter and other methods, but these methods mostly require external carbon sources, which leads to increased operating costs, and the structure is not compact enough and occupies a large area. For example, the Chinese utility model patent with authorization announcement number CN207143037U discloses a high ammonia nitrogen wastewater denitrification treatment device, which includes a denitrification tank, a pre-aeration tank, a denitrification tank and a sedimentation tank. The mixing degree of the wastewater is increased by the setting of a propeller, and the setting of brush fillers and spherical fillers in the pre-aeration tank and the denitrification tank increases the reproduction of bacteria, providing bacteria guarantee for the treatment of high ammonia nitrogen wastewater. The setting of the inclined pipe of the sedimentation tank reduces the sludge turning over and increases the clarity of the effluent, but the various tanks of the device are dispersed, thereby increasing the overall footprint of the device. For example, a Chinese utility model patent with authorization announcement number CN219174335U discloses a sewage denitrification treatment device, which includes an inner-ring short-cut denitrification zone and an outer-ring anaerobic ammonium oxidation zone, and the two rings are nested and connected. The raw water tank is connected to the aeration sedimentation tank through a first water inlet pump, and the aeration sedimentation tank is connected to the bottom of the inner-ring short-cut denitrification zone of the short-cut denitrification-anaerobic ammonium oxidation reactor through a third water inlet pump. The output end of the third water inlet pump is connected to the output end of the second water inlet pump. The device sets the aeration sedimentation tank and the short-cut denitrification-anaerobic ammonium oxidation reactor separately, and the overall structure of the device is still not compact enough. Utility Model Content

[0004] The utility model aims to provide a nested short-range denitrification clarifier, the overall structure of which is more compact, thereby reducing the floor space occupied by the equipment, while reducing the use of carbon sources, shortening the reaction time and reducing the amount of sludge produced.

[0005] The purpose of this utility model is achieved through the following technical solutions:

[0006] A nested short-range denitrification clarification tank comprises a main tank body, and an equipment room is arranged at the lower part of the main tank body, and a solid-liquid separation tank, a water distribution ring and a denitrification reaction ring are arranged in sequence from the inside to the outside on the upper part of the main tank body, wherein the denitrification reaction ring comprises a first denitrification tank, a second denitrification tank, a first dosing tank and a second dosing tank which are connected in sequence, an input end of the first denitrification tank is provided with a water inlet pipe, and the second dosing tank is provided with a first ring body connecting port which is connected to the upper part of the inner water distribution ring, and the interior of the solid-liquid separation tank is formed in sequence from bottom to top A sludge sedimentation area, a water distribution area, an inclined tube packing layer and a clean water area, wherein the water distribution area is provided with a second ring body connecting hole connected to the lower end of the water distribution ring, the clean water area is provided with a drainage pipe assembly, a sludge scraping assembly is provided inside the sludge sedimentation area, a mud hopper is provided at the lower side of the sludge sedimentation area, a sludge discharge pump and a sludge return pump are provided in the equipment room, and the sludge discharge pump and the sludge return pump are connected to the sludge hopper through corresponding pipelines respectively, and the output side of the sludge return pump is connected to the second dosing tank through a pipeline.

[0007] The input side of the upper end of the first denitrification tank is connected with the water inlet pipe, a first high denitrification filler layer is provided in the middle of the first denitrification tank, the output side of the lower end of the first denitrification tank is connected with the lower end of the adjacent second denitrification tank through the first tank body connecting port, an aeration device is provided at the lower end of the second denitrification tank, a second high denitrification filler layer is provided in the middle of the second denitrification tank, a second tank body connecting port is provided on the output side of the upper end of the second denitrification tank to communicate with the adjacent first dosing tank, and a reflux pump is provided on the side of the lower end of the second denitrification tank close to the second tank body connecting port, and the reflux pump is connected with the input side of the upper end of the first denitrification tank through a denitrification reflux pipe.

[0008] A first dissolved oxygen detector is provided at the lower side of the first high denitrification filler layer, and a second dissolved oxygen detector is provided at the lower side of the second high denitrification filler layer.

[0009] A plug flow agitator is provided in the first denitrification tank.

[0010] The aeration device is connected to the aeration fan arranged in the equipment room through an aeration air duct.

[0011] The first dosing tank is provided with a first guide plate, a first dosing pipe and a first stirring assembly in sequence along the water flow direction. After the water is input, it flows downwards through the blocking effect of the first guide plate and then bends and flows upwards.

[0012] The first dosing tank is connected to the second dosing tank through a third tank body connecting port, and a second dosing pipe, a second guide plate and a second stirring assembly are sequentially arranged in the second dosing tank along the water flow direction, a first sludge return pipe is arranged on the input side of the sludge return pump and is connected to the mud hopper, a second sludge return pipe is arranged on the output side of the sludge return pump and is connected to the second dosing tank, and an output end of the second sludge return pipe is located at the lower end of the second dosing pipe.

[0013] The scraper assembly in the sludge sedimentation area includes a scraper disc, and the scraper disc is provided with vertical grid bars. The upper end of the main pool body is provided with a scraper drive motor, and the power shaft of the scraper drive motor is connected to the middle of the scraper disc through a connecting shaft.

[0014] The drainage pipe assembly in the clean water area includes drainage branch channels and a drainage main pipe, and each drainage branch channel is vertically arranged with respect to the drainage main pipe, each drainage branch channel has an opening at the upper end, and the lower middle side of each drainage branch channel is connected with the drainage main pipe.

[0015] The main tank body is provided with a partition plate separating the equipment room and the denitrification reaction ring.

[0016] The advantages and positive effects of the utility model are:

[0017] 1. The utility model integrates each tank body and equipment room into the main tank body, and the structure of the whole device is more compact, thereby reducing the equipment footprint. The denitrification tanks and dosing tanks are arranged in the outermost denitrification reaction ring in sequence along the circumferential direction to ensure sufficient reaction, and the water distribution ring between the denitrification reaction ring and the solid-liquid separation tank can play a role in buffering and uniform water distribution. The solid-liquid separation tank in the center ensures the solid-liquid separation effect. At the same time, devices such as sludge return pump, sludge discharge pump, aeration fan, etc. are all concentrated in the equipment room at the lower end of the main tank body, so that the utility model can meet the needs of sewage treatment and related control.

[0018] 2. The utility model uses two dissolved oxygen detectors to monitor the dissolved oxygen conditions in the two denitrification tanks in real time to control them to meet the low dissolved oxygen process environment requirements of short-range nitrification and denitrification. The internal filler of the second denitrification tank will separate nitrite functional bacteria (AOB) as the dominant bacteria in the low dissolved oxygen environment, and directly convert ammonia into nitrite. Then the water in the second denitrification tank will flow back into the first denitrification tank through the denitrification return pipe through the reflux pump. The anaerobic ammonia oxidizing bacteria filler in the first denitrification tank converts the ammonia nitrogen in the sewage into nitrogen in the nitrite. The invention can convert nitrite into nitrate, thereby achieving the purpose of deep denitrification. Compared with the traditional whole-process nitrification and denitrification, the utility model reduces the link of converting nitrite into nitrate, thereby reducing the energy input and carbon source use of the system, shortening the nitrification reaction time, and further reducing the pool capacity, saving investment. In addition, compared with the traditional nitrate denitrification bacteria, the nitrite denitrifying bacteria can produce 20-30% less mud during the reaction process. At the same time, the system of the utility model adopts the contact oxidation biofilm method, that is, the microorganisms are fixed on the filler. Compared with the activated sludge method, the utility model produces less mud. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional view of the utility model.

[0020] Figure 2 for Figure 1 A top view of the utility model,

[0021] Figure 3 for Figure 2 Schematic diagram of the structure of the first denitrification tank.

[0022] Figure 4 for Figure 2 Schematic diagram of the structure of the second denitrification tank.

[0023] Figure 5 for Figure 2 Schematic diagram of the structure of the first dosing tank and the second dosing tank.

[0024] Among them, 1 is a denitrification reaction ring, 2 is a water distribution ring, 3 is a water distribution area, 301 is a second ring body connecting hole, 302 is a support beam, 4 is a sludge sedimentation area, 401 is a sludge scraper plate, 4011 is a grille bar, 402 is a mud bucket, 403 is a sludge scraper drive motor, 5 is an inclined tube packing layer, 6 is a drainage pipe assembly, 601 is a drainage branch channel, 602 is a drainage main pipe, 7 is a clean water area, 8 is a partition, 9 is an equipment room, 901 is a sludge discharge pump, 902 is an aeration fan, 903 is a sludge return pump, 10 is a water inlet pipe, 11 is the first denitrification tank, 1101 is the first high denitrification packing layer, 1102 is the first dissolved oxygen detector, 1103 is a plug flow agitator, 12 is the second denitrification tank, 1201 is the second high denitrification packing Material layer, 1202 is the second dissolved oxygen detector, 1203 is the aeration device, 1204 is the reflux pump, 13 is the first dosing tank, 1301 is the first guide plate, 1302 is the first dosing pipe, 1303 is the first stirring assembly, 14 is the second dosing tank, 1401 is the second guide plate, 1402 is the second dosing pipe, 1403 is the second stirring assembly, 1404 is the first ring body connecting port, 15 is the first tank body connecting port, 16 is the denitrification reflux pipe, 17 is the second tank body connecting port, 18 is the third tank body connecting port, 19 is the aeration air duct, 20 is the first sludge discharge pipe, 21 is the second sludge return pipe, 22 is the first sludge return pipe, 23 is the solid-liquid separation tank, 24 is the second sludge discharge pipe, and 25 is the main tank body. DETAILED DESCRIPTION

[0025] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0026] like Figures 1 to 5 As shown, the utility model includes a main pool body 25, and the lower part of the main pool body 25 is provided with an equipment room 9, and the upper part of the main pool body 25 is provided with a solid-liquid separation tank 23, a water distribution ring 2 and a denitrification reaction ring 1 in sequence from the inside to the outside, wherein Figure 2 As shown, the denitrification reaction ring 1 includes a first denitrification tank 11, a second denitrification tank 12, a first dosing tank 13 and a second dosing tank 14 arranged along the circumferential direction and connected in sequence. The input end of the first denitrification tank 11 is provided with a water inlet pipe 10, and the second dosing tank 14 is provided with a first ring body communication port 1404 connected to the upper part of the inner water distribution ring 2, as shown in FIG. Figure 1As shown, a sludge sedimentation area 4, a water distribution area 3, an inclined tube packing layer 5 and a clean water area 7 are formed in sequence from bottom to top inside the solid-liquid separation tank 23, wherein the water distribution area 3 is provided with a second ring body connecting hole 301 connected to the lower end of the water distribution ring 2, the clean water area 7 is provided with a drainage pipe assembly 6, a sludge scraping assembly is provided inside the sludge sedimentation area 4, a mud hopper 402 is provided at the lower side of the sludge sedimentation area 4, a sludge discharge pump 901 and a sludge return pump 903 are provided in the equipment room 9, and the sludge discharge pump 901 and the sludge return pump 903 are respectively connected to the sludge hopper 402 through corresponding pipelines, and the output side of the sludge return pump 903 is connected to the second dosing tank 14 through a pipeline. When the utility model is working, the external wastewater flows into the first denitrification tank 11 through the water inlet pipe 10, and then enters the water distribution ring 2 after passing through the first denitrification tank 11, the second denitrification tank 12, the first dosing tank 13 and the second dosing tank 14 in sequence. The water distribution ring 2 plays the role of buffering and uniform water distribution. The bottom of the water distribution ring 2 is at an angle of 45° and is biased to the side of the solid-liquid separation tank 23. Water enters the upper part of the water distribution ring 2, and the water in the water distribution ring 2 passes through the second ring body connecting hole 3 at the lower end. 01 flows into the water distribution area 3 of the solid-liquid separation tank 23, the liquid water in the water distribution area 3 rises and passes through the inclined tube packing layer 5 into the clean water area 7, and is finally discharged by the drainage pipe assembly 6, the sludge impurities in the water distribution area 3 are precipitated and fall into the sludge sedimentation area 4, and finally fall into the mud hopper 402. When the sludge return pump 903 is started, the sludge in the mud hopper 402 is circulated and flows into the second dosing tank 14 for reaction. When the sludge discharge pump 901 is started, the sludge in the mud hopper 402 is discharged.

[0027] like Figures 3-4As shown, in this embodiment, the input side of the upper end of the first denitrification tank 11 is connected to the water inlet pipe 10, a first high denitrification filler layer 1101 is provided in the middle of the first denitrification tank 11, and a first dissolved oxygen detector 1102 is provided on the lower side of the first high denitrification filler layer 1101, the output side of the lower end of the first denitrification tank 11 is connected to the lower end of the adjacent second denitrification tank 12 through the first tank body connecting port 15, an aeration device 1203 is provided at the lower end of the second denitrification tank 12, a second high denitrification filler layer 1201 is provided in the middle of the second denitrification tank 12, and a second dissolved oxygen detector 1202 is provided on the lower side of the second high denitrification filler layer 1201, a second tank body connecting port 17 is provided on the output side of the upper end of the second denitrification tank 12 to communicate with the adjacent first dosing tank 13, and a reflux pump 1204 is provided on the lower end of the second denitrification tank 12 near the second tank body connecting port 17, and the reflux pump 1204 is connected to the input side of the upper end of the first denitrification tank 11 through the denitrification reflux pipe 16. The first high denitrification filler layer 1101 and the second high denitrification filler layer 1201 are both provided with high denitrification fillers to achieve wastewater deammonification treatment, which is a well-known technology in the art. For example, the fillers in CN219174335U can be used. However, the utility model uses the first dissolved oxygen detector 1102 and the second dissolved oxygen detector 1202 to monitor in real time the dissolved oxygen conditions in the first denitrification tank 11 and the second denitrification tank 12 through the PLC system to achieve the low dissolved oxygen process environment requirements of short-range nitrification and denitrification. The internal filler of the second denitrification tank 12 will separate the nitrite functional bacteria (AOB) as the dominant bacteria in the low dissolved oxygen environment, and directly convert ammonia into nitrite, and then the water in the second denitrification tank 12 Then, it flows back into the first denitrification tank 11 through the denitrification reflux pipe 16 through the reflux pump 1204. The anaerobic ammonia-oxidizing bacteria filler in the first denitrification tank 11 converts the nitrogen in the ammonia nitrogen and nitrite in the sewage into nitrogen gas, thereby achieving the purpose of deep denitrification. Compared with the traditional full-process nitrification and denitrification, the utility model reduces the conversion of nitrite into nitrate, thereby reducing the energy input and carbon source use of the system, and shortens the nitrification reaction time, reduces the tank capacity, and saves investment. In addition, compared with traditional nitrate denitrifying bacteria, nitrite denitrifying bacteria can produce 20-30% less mud during the reaction process. At the same time, the utility model system adopts the contact oxidation biofilm method, that is, the microorganisms are fixed on the filler. Compared with the activated sludge method, the utility model produces less mud. In this embodiment, the first dissolved oxygen detector 1102 and the second dissolved oxygen detector 1202 are purchased from Shanghai Lanhua Intelligent Sensing Technology Co., Ltd.

[0028] like Figure 3 As shown, in this embodiment, a plug flow agitator 1103 is provided in the first denitrification tank 11 for driving the wastewater at the bottom of the tank to flow toward the first tank body connecting port 15. In this embodiment, the plug flow agitator 1103 is purchased from Shandong Laixin Machinery Co., Ltd.

[0029] like Figures 4-5 As shown, in this embodiment, the aeration device 1203 is connected to the aeration fan 902 provided in the equipment room 9 through the aeration air duct 19. In this embodiment, the aeration device 1203 and the aeration fan 902 are purchased from Shandong Zhangqiu Drum Aeration Fan Co., Ltd.

[0030] like Figure 4 As shown, a first control valve can be provided on the second cell body communication port 17 as required, and when the liquids in the two denitrification cells are fully reacted, the first control valve is opened again to open the second cell body communication port 17. The first control valve is a well-known technology in the art and is a commercially available product.

[0031] like Figure 5 As shown, in this embodiment, the first dosing tank 13 is provided with a first guide plate 1301, a first dosing tube 1302 and a first stirring assembly 1303 in sequence along the water flow direction, wherein after water is input through the second tank body communication port 17, it first flows downward due to the blockage of the first guide plate 1301, then bends and flows upward to dissolve with the drug output by the first dosing tube 1302, and then is stirred evenly by the first stirring assembly 1303. Figure 5 As shown, in this embodiment, the first dosing tank 13 and the second dosing tank 14 are connected through the third tank body connecting port 18 , and the solution stirred by the first stirring component 1303 eventually flows into the second dosing tank 14 through the third tank body connecting port 18 .

[0032] like Figure 5 As shown, in this embodiment, the second dosing tank 14 is provided with a second dosing pipe 1402, a second guide plate 1401 and a second stirring assembly 1403 in sequence along the water flow direction, and in addition, the first sludge return pipe 22 is provided on the input side of the sludge return pump 903 to communicate with the mud bucket 402, and the second sludge return pipe 21 is provided on the output side of the sludge return pump 903 to communicate with the second dosing tank 14, and the output end of the second sludge return pipe 21 is located on the side of the second guide plate 1401 close to the third tank body connecting port 18 and located at the lower end of the second dosing pipe 1402. After the incoming water flows into the second dosing tank 14 through the third tank body connecting port 18, it first flows downward, and the medicine output from the second dosing pipe 1402 and the returned sludge are mixed with the incoming water, and then the incoming water bypasses the lower end of the second guide plate 1401 and is stirred evenly through the second stirring assembly 1403.

[0033] like Figure 2As shown, the second dosing tank 14 is provided with a first ring body communication port 1404 connected to the upper part of the inner water distribution ring 2, and a second control valve can be provided on the first ring body communication port 1404 as required. When the liquid medicine is fully mixed, the second control valve is opened again to connect the first ring body communication port. The second control valve is a well-known technology in the art and is a commercially available product.

[0034] In this embodiment, the first stirring component 1303 and the second stirring component 1403 have the same structure, and both include a stirring motor and a stirring blade driven by the stirring motor.

[0035] In this embodiment, the drug applied by the first dosing tube 1302 is PAC (polyaluminum chloride), which plays a flocculation role, so that the colloids and suspended matter in the water form a flocculent structure; the drug applied by the second dosing tube 1402 is PAM (polyacrylamide), which plays a coagulant role. The sludge return role is to serve as a contact medium to achieve carrier contact coagulation. The returned sludge and the coagulant aid PAM applied by the second dosing tube work together to enhance floc adsorption, accelerate the coagulation process and ensure the quality of the generated flocs (forming large pieces of alum flowers).

[0036] like Figure 1 As shown, in this embodiment, the scraper assembly in the sludge sedimentation area 4 includes a scraper disc 401, and the scraper disc 401 is provided with vertical grid bars 4011, the upper end of the main pool body 25 is provided with a scraper drive motor 403, and the power shaft of the scraper drive motor 403 is connected to the middle part of the scraper disc 401 through a connecting shaft, and the scraper disc 401 is driven to rotate by the scraper drive motor 403, and the rotation of the scraper disc 401 drives the grid bars 4011 thereon to rotate, so that the concentrated sludge concentration at various locations in the sludge sedimentation area 4 is consistent, and the precipitated sludge is made more uniform, and the scraper disc 401 is provided with an opening for the sludge to settle through and fall into the mud bucket 402.

[0037] like Figures 1-2 As shown, in this embodiment, the drainage pipe assembly 6 in the clean water area 7 includes a drainage branch channel 601 and a drainage main pipe 602, and each drainage branch channel 601 is vertically arranged to the drainage main pipe 602, and each drainage branch channel 601 has an opening at the upper end for water overflow, and the lower side of the middle part of each drainage branch channel 601 is connected to the drainage main pipe 602, and the treated water passes through each drainage branch channel 601 and finally flows out of the drainage main pipe 602.

[0038] like Figure 1 As shown, in this embodiment, a partition 8 is provided in the main pool body 25 to separate the equipment room 9 from the denitrification reaction loop 1. Figure 1 and Figure 5As shown, the input side of the sludge discharge pump 901 is connected to the sludge bucket 402 through the first sludge discharge pipe 20. Figure 2 As shown, the output side of the sludge discharge pump 901 is connected to the external pipeline through the second sludge discharge pipe 24. Figure 1 As shown, a support beam 302 is provided in the clear water area 7 at the upper end of the solid-liquid separation tank 23 , and the drainage pipe assembly 6 is provided on the support beam 302 .

[0039] The working principle of the utility model is:

[0040] When the utility model is working, the external wastewater flows into the first denitrification tank 11 of the denitrification reaction ring 1 through the water inlet pipe 10, and then enters the water distribution ring 2 after the denitrification treatment is completed after passing through the first denitrification tank 11, the second denitrification tank 12, the first dosing tank 13 and the second dosing tank 14 in sequence. The water distribution ring 2 plays the role of buffering and uniform water distribution. Water enters the upper part of the water distribution ring 2, and the water in the water distribution ring 2 flows into the water distribution area 3 of the solid-liquid separation tank 23 through the second ring body connecting hole 301 at the lower end, and the liquid water in the solid-liquid separation tank 23 rises and passes through the inclined tube packing layer 5 to enter the clear water area 7, and is finally discharged by the drainage pipe assembly 6. The sludge impurities in the solid-liquid separation tank 23 are precipitated into the sludge sedimentation area 4 and finally fall into the mud hopper 402. An equipment room 9 is provided at the lower end of the main tank body 25, and a sludge discharge pump 901, a sludge return pump 903 and an aeration fan 902 are provided in the equipment room 9. When the sludge return pump 903 is started, the sludge in the mud hopper 402 is circulated and flows into the second dosing tank 14 for reaction. When the sludge discharge pump 901 is started, the sludge in the mud hopper 402 is discharged. An aeration device 1203 is provided at the bottom of the second dosing tank 14, and the aeration device 1203 is supplied with air for aeration through the aeration fan 902.

[0041] The utility model integrates each tank body and the equipment room 9 into the main tank body 25, and the structure of the whole device is more compact, thereby reducing the equipment footprint. During the denitrification reaction, the utility model monitors the dissolved oxygen conditions in the two denitrification tanks in real time through two dissolved oxygen detectors, so as to achieve the low dissolved oxygen process environment requirements of short-range nitrification and denitrification. The internal filler of the second denitrification tank 12 will separate the nitrite functional bacteria (AOB) as the dominant bacteria in the low dissolved oxygen environment, and directly convert ammonia into nitrite. Then the water in the second denitrification tank 12 is re-flowed into the first denitrification tank 11 through the denitrification reflux pipe 16 through the reflux pump 1204. The anaerobic ammonia-oxidizing bacteria filler in the first denitrification tank 11 converts the ammonia nitrogen in the sewage and the nitrogen in the nitrite into nitrogen gas, thereby achieving the purpose of deep denitrification. Compared with the traditional full-process nitrification and denitrification, the utility model reduces the conversion of nitrite into nitrate, thereby reducing the energy input and carbon source use of the system, and shortening the nitrification reaction time, while further reducing the tank capacity and saving investment. In addition, compared with traditional nitrate denitrifying bacteria, nitrite denitrifying bacteria can produce 20-30% less sludge during the reaction process. At the same time, the system of the utility model adopts the contact oxidation biofilm method, that is, the microorganisms are fixed on the filler. Compared with the activated sludge method, the utility model produces less sludge.

Claims

1. A nested short-range denitrification clarifier, characterized in that: The invention comprises a main tank body (25), wherein the lower part of the main tank body (25) is provided with an equipment room (9), and the upper part of the main tank body (25) is provided with a solid-liquid separation tank (23), a water distribution ring (2) and a denitrification reaction ring (1) in sequence from the inside to the outside, wherein the denitrification reaction ring (1) comprises a first denitrification tank (11), a second denitrification tank (12), a first dosing tank (13) and a second dosing tank (14) which are connected in sequence, the input end of the first denitrification tank (11) is provided with a water inlet pipe (10), the second dosing tank (14) is provided with a first ring body connecting port (1404) which is connected with the upper part of the inner water distribution ring (2), and the interior of the solid-liquid separation tank (23) is formed with a sludge sedimentation area (4), a water distribution ring (2) and a second dosing tank (14) in sequence from bottom to top. A water zone (3), an inclined tube packing layer (5) and a clean water zone (7), wherein the water distribution zone (3) is provided with a second ring body connecting hole (301) connected to the lower end of the water distribution ring (2), the clean water zone (7) is provided with a drainage pipe assembly (6), a sludge scraping assembly is provided inside the sludge sedimentation zone (4), a mud bucket (402) is provided at the lower side of the sludge sedimentation zone (4), a sludge discharge pump (901) and a sludge return pump (903) are provided in the equipment room (9), and the sludge discharge pump (901) and the sludge return pump (903) are respectively connected to the mud bucket (402) through corresponding pipelines, and the output side of the sludge return pump (903) is connected to the second dosing tank (14) through a pipeline.

2. The nested short-cut denitrification clarifier according to claim 1, characterized in that: The input side of the upper end of the first denitrification tank (11) is connected to the water inlet pipe (10), a first high denitrification filler layer (1101) is provided in the middle of the first denitrification tank (11), the output side of the lower end of the first denitrification tank (11) is connected to the lower end of the adjacent second denitrification tank (12) through a first tank body connecting port (15), an aeration device (1203) is provided at the lower end of the second denitrification tank (12), a second high denitrification filler layer (1201) is provided in the middle of the second denitrification tank (12), a second tank body connecting port (17) is provided at the output side of the upper end of the second denitrification tank (12) to communicate with the adjacent first dosing tank (13), and a reflux pump (1204) is provided at the lower end of the second denitrification tank (12) near the second tank body connecting port (17), and the reflux pump (1204) is connected to the input side of the upper end of the first denitrification tank (11) through a denitrification reflux pipe (16).

3. The nested short-cut denitrification clarifier according to claim 2, characterized in that: A first dissolved oxygen detector (1102) is provided at the lower side of the first high denitrification filler layer (1101), and a second dissolved oxygen detector (1202) is provided at the lower side of the second high denitrification filler layer (1201).

4. The nested short-cut denitrification clarifier according to claim 2, characterized in that: A plug flow agitator (1103) is provided in the first denitrification tank (11).

5. The nested short-cut denitrification clarifier according to claim 2, characterized in that: The aeration device (1203) is connected to the aeration fan (902) disposed in the equipment room (9) via an aeration air duct (19).

6. The nested short-cut denitrification clarifier according to claim 1, characterized in that: A first guide plate (1301), a first dosing pipe (1302) and a first stirring assembly (1303) are sequentially arranged inside the first dosing tank (13) along the water flow direction, wherein after water is input, it first flows downward through the blocking effect of the first guide plate (1301) and then bends and flows upward.

7. The nested short-cut denitrification clarifier according to claim 1, characterized in that: The first dosing tank (13) and the second dosing tank (14) are connected via a third tank body connecting port (18), and a second dosing pipe (1402), a second guide plate (1401) and a second stirring assembly (1403) are sequentially arranged in the second dosing tank (14) along the water flow direction; a first sludge return pipe (22) is arranged on the input side of the sludge return pump (903) and is connected to the sludge hopper (402); a second sludge return pipe (21) is arranged on the output side of the sludge return pump (903) and is connected to the second dosing tank (14), and an output end of the second sludge return pipe (21) is located at the lower end of the second dosing pipe (1402).

8. The nested short-cut denitrification clarifier according to claim 1, characterized in that: The sludge scraping assembly in the sludge settling area (4) comprises a sludge scraping disc (401), and the sludge scraping disc (401) is provided with vertical grid bars (4011). A sludge scraping driving motor (403) is provided at the upper end of the main pool body (25), and the power shaft of the sludge scraping driving motor (403) is connected to the middle of the sludge scraping disc (401) via a connecting shaft.

9. The nested short-cut denitrification clarifier according to claim 1, characterized in that: The drainage pipe assembly (6) in the clean water area (7) comprises a drainage branch channel (601) and a drainage main pipe (602), and each drainage branch channel (601) is vertically arranged with respect to the drainage main pipe (602), each drainage branch channel (601) is open at the upper end, and the lower middle part of each drainage branch channel (601) is connected with the drainage main pipe (602).

10. The nested short-cut denitrification clarifier according to claim 1, characterized in that: A partition (8) is provided in the main pool body (25) for separating the equipment room (9) and the denitrification reaction ring (1).

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