Tail water denitrification system for sewage plant

Abstract

The utility model provides a tail water denitrification system for a sewage plant, which comprises an adjusting water tank, a main water distribution tank, a deep denitrification unit and a clean water tank, and the deep denitrification unit comprises a plurality of denitrification reaction devices; the tail water is subjected to denitrification treatment by taking elemental sulfur, an iron-carbon mixture and activated carbon as fillers in a denitrification reaction device, and nitrate nitrogen in the tail water is reduced into nitrogen as an electron acceptor, so that an autotrophic denitrification nitrogen removal process is realized; and in combination with carbon-iron micro-electrolysis, the dephosphorization effect is achieved. And the nitrogen removal efficiency is not influenced by the fluctuation change of the organic matter content of the tail water, so that the operation cost of the system is reduced, and the stability of the nitrogen removal efficiency of the system is guaranteed. Meanwhile, the main water distribution tank is matched with the distribution water tanks to form two-stage water distribution, so that the uniformity of water inlet flow and water inlet quality of the denitrification reaction device is improved to the greatest extent, impact and abrasion in the denitrification reaction device can be reduced, and stable operation of the denitrification system is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of sewage treatment, in particular to a tail water denitrification system of a sewage plant. Background Art

[0002] Large amounts of nitrogen and phosphorus discharge will cause eutrophication of water bodies, which may lead to imbalances in aquatic ecosystems, such as causing blue algae blooms. Therefore, in order to protect the environment and reduce the impact of nitrogen pollution on the ecological environment of water bodies, it is necessary to denitrify the tailwater from sewage treatment plants.

[0003] In the prior art, heterotrophic denitrification denitrification process is often used to denitrify the tail water of sewage treatment plants. Although the heterotrophic denitrification denitrification process has a high denitrification efficiency, it has high requirements for the organic matter content in the tail water. In actual use, the heterotrophic denitrification denitrification process is greatly affected by the fluctuation of organic matter content, and it is often necessary to accurately add an organic carbon source according to the fluctuation of organic matter content, which leads to unstable denitrification effect of tail water treatment and high denitrification cost. In addition, more sludge will be produced, which will increase the cost of subsequent treatment.

[0004] Therefore, it is necessary to provide a tail water denitrification system with low cost and stable denitrification effect. Utility Model Content

[0005] Aiming at the technical problems in the prior art of using heterotrophic denitrification denitrification process to treat tail water of sewage plant, such as high cost and poor stability of denitrification effect, the utility model provides a tail water denitrification system of sewage plant.

[0006] A sewage plant tailwater denitrification system comprises a regulating water tank, a main water distribution tank, a deep denitrification unit and a clear water tank which are connected in sequence, characterized in that the deep denitrification unit comprises a plurality of denitrification reaction devices, the denitrification reaction device comprises a device body, the denitrification reaction device comprises a device body, a distribution water tank is arranged above the device body, the distribution water tank is connected with the main water distribution tank through a distribution pipe, a system outlet pipe is arranged at the bottom of the device body, and the system outlet pipe is connected with the clear water tank through an outlet pump; a filter plate with a plurality of filter holes is arranged in the device body, a filter bed with elemental sulfur, iron-carbon mixture and activated carbon as fillers is filled on the filter plate; a backwash drain pipe is arranged on one side of the device body above the filter bed; a backwash air inlet pipe and a backwash water inlet pipe are arranged on one side of the device body below the filter bed; and the backwash air inlet pipe is connected with a backwash fan, and the backwash water inlet pipe is connected with the clear water tank through a backwash pump.

[0007] Furthermore, it also includes a backwash water collection tank, which is connected to the backwash drainage pipe through a drainage pump.

[0008] Furthermore, in the filter bed, the elemental sulfur accounts for 60%, and its particle size is 5-8 mm; the iron-carbon mixture accounts for 20%, and its particle size is 6-10 mm; the activated carbon accounts for 20%, and its particle size is 5-8 mm.

[0009] Furthermore, the water distribution pipe and the system water outlet pipe are both provided with a flow meter and a TN detector.

[0010] Furthermore, a booster pump and a screw air compressor are sequentially arranged on the water distribution pipe, and the screw air compressor is connected to an air storage tank.

[0011] Furthermore, a pressing plate is provided in the body of the device, and the pressing plate is located above the filter material bed. A plurality of mesh holes are provided on the pressing plate, and the sizes of the mesh holes and the filter holes are smaller than the minimum particle size of the filler.

[0012] Furthermore, valves are respectively provided on the water distribution pipe, the system water outlet pipe, the backwash air inlet pipe, the backwash water inlet pipe and the backwash drain pipe.

[0013] Furthermore, a water distribution pipe and an aeration pipe are provided in the device body below the filter bed, the water distribution pipe is connected to the backwash water inlet pipe, and the aeration pipe is connected to the backwash air inlet pipe; and the water distribution pipe is provided with a plurality of water distribution holes; the aeration pipe is provided with a plurality of aeration holes.

[0014] The beneficial effects of the utility model are as follows: the utility model provides a sewage plant tailwater denitrification system, including a regulating water tank, a main water distribution tank, a deep denitrification unit and a clear water tank, wherein the deep denitrification unit includes several denitrification reaction devices; by using elemental sulfur, iron-carbon mixture and activated carbon as fillers in the denitrification reaction device to denitrify the tailwater, the nitrate nitrogen in the tailwater is reduced to nitrogen gas as an electron acceptor, thereby realizing the autotrophic denitrification denitrification process; and in combination with carbon-iron micro-electrolysis, a certain phosphorus removal effect is achieved. No external organic carbon source is required, and the denitrification efficiency is not affected by the fluctuation of the organic matter content in the tailwater, thereby reducing the operating cost of the system and ensuring the stability of the denitrification efficiency of the system. At the same time, by setting a main water distribution tank to buffer and evenly distribute the amount of water flowing from the water distribution pipe into the denitrification reaction device from the regulating water tank, and coordinating the setting of each distribution tank to form a two-stage distribution water distribution, the uniformity of the water inlet flow and water quality of the denitrification reaction device is maximized, and at the same time, the impact and wear in the denitrification reaction device can be reduced to ensure the stable operation of the denitrification system.

[0015] In addition, a recoil water inlet pipe is provided, and a recoil air inlet pipe is used to regularly stir and flush the filler of the filter bed, so that the filler is fully utilized, which is beneficial to reduce operating costs and ensure the stability of the denitrification effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1A schematic diagram of a process flow of a sewage plant tail water denitrification system provided by the utility model;

[0017] Figure 2 A schematic diagram of the structure of a sewage plant tail water denitrification system provided by the utility model;

[0018] Figure 3 The utility model provides a structural schematic diagram of a denitrification reaction device.

[0019] Figure ID

[0020] 0. Regulating water tank; 1. Main water distribution tank; 2. Deep denitrification unit; 21. Device body; 22. Filter plate; 23. Filter media bed; 24. Press plate; 3. Clean water tank; 4. Distribution tank; 5. Water distribution pipe; 6. System outlet pipe; 7. Backwash drain pipe; 8. Backwash air inlet pipe; 9. Backwash water inlet pipe; 10. Backwash fan; 11. Backwash pump; 12. Backwash water collection tank; 13. Drainage pump; 14. Flow meter; 15. Booster pump; 16. Screw air compressor; 17. Valve; 18. Water distribution pipe; 19. Aeration pipe; 20. Outlet pump. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with specific embodiments. These embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] refer to Figure 1 As shown, the utility model provides a sewage plant tailwater denitrification system, including a regulating water tank 0, a deep denitrification unit 2 and a clear water tank 3 connected in sequence. In this embodiment, in order to speed up the tailwater denitrification efficiency, two deep denitrification units 2 are provided to treat the tailwater at the same time.

[0023] Specifically, the deep denitrification unit 2 includes several denitrification reaction devices (not shown in the figure). Figure 2 and Figure 3As shown, there is at least one denitrification reaction device; the denitrification reaction device includes a device body 21, a distribution water tank 4 is provided on the top of the device body 21, a water distribution pipe 5 is provided on the distribution water tank 4, a system water outlet pipe 6 is provided at the bottom of the device body 21, and the water distribution pipes 5 are all connected to the main water distribution tank 1, a system water outlet pipe 6 is provided at the bottom of the device body 21, and the system water outlet pipe 6 is connected to the clean water tank 3 through a water outlet pump 20. In this embodiment, the deep denitrification unit 2 includes 12 denitrification reaction devices connected to the main water distribution tank 1.

[0024] The regulating water tank 0 is used to collect and store tail water from the sewage treatment plant, and can effectively balance the water quality by adjusting the water flow, utilizing the hydraulic retention time, and adding reagents, etc., to ensure the stability of the water quality and quantity of the water input from the regulating water tank to the deep denitrification unit 2 through the water distribution pipe 5; the clean water tank 3 is used to collect and store the clean water after denitrification treatment by the deep denitrification unit 2, and discharge the clean water to the outside or the next tail water treatment device. At the same time, by setting the total water distribution tank 1 to buffer and evenly distribute the amount of water flowing from the regulating water tank 0 into the denitrification reaction device from the water distribution pipe 5, and cooperating with the setting of each distribution tank 41 to form a two-stage distribution water distribution, the uniformity of the water flow and water quality of the denitrification reaction device is maximized, and at the same time, the impact and wear in the denitrification reaction device can be reduced to ensure the stable operation of the denitrification system.

[0025] Among them, a filter plate 22 with a plurality of filter holes (not shown in the figure) is provided in the device body 21, and a filter bed 23 with elemental sulfur, iron-carbon mixture and activated carbon as fillers is filled on the filter plate 22. In this embodiment, in the filter bed 23, the elemental sulfur accounts for 60%, and its particle size is 5-8mm; the iron-carbon mixture accounts for 20%, and the iron-carbon mixture is made by mechanical pressing with a mass ratio of iron to carbon of 6:4; the particle size of the pressed iron-carbon mixture is 6-10mm; the activated carbon accounts for 20%, and its particle size is 5-8mm.

[0026] The water distribution pipe 5 is also provided with a booster pump 15 and a screw air compressor 16 in sequence, and the screw air compressor 16 is connected to an air storage tank (not shown in the figure). The air storage tank can store the compressed air generated by the screw air compressor 16 to ensure that the system can still provide a stable supply of compressed air when the screw air compressor 16 stops or the air pressure fluctuates.

[0027] When denitrifying the tail water, the nitrogen- and phosphorus-containing tail water in the main water distribution tank 1 passes through the water distribution pipe 5, and after being pressurized and lifted by the pressure pump 15, it is aerated by the screw air compressor 16. After the aerated tail water enters the distribution tank 4 at the top of the device body 21 and is evenly distributed, the tail water flows down from the distribution tank 4 evenly to the top of the filter bed 23; the tail water relies on gravity to pass from top to bottom through the filter bed 23 filled with elemental sulfur, iron-carbon mixture and activated carbon as fillers. Then, sulfur and iron are used as electron donors to reduce the nitrate nitrogen in the tail water as electron acceptors to nitrogen gas, thereby realizing the autotrophic denitrification process; at the same time, combined with carbon-iron micro-electrolysis, it has a certain phosphorus removal effect. Among them, the main chemical reaction equation occurring in the denitrification process is: S 0 +1.2NO3 - +0.4H2O→SO4 2- +0.6N2+0.8H + ; 5Fe 0 +2NO3 - +H2O→5Fe 2+ +N2↑+12OH - ;Fe+2H2O+PO4 - →FePO4↓+H2↑+2OH - .

[0028] A backwash drain pipe 7 is provided on one side of the device body 21 above the filter bed 23; a backwash air inlet pipe 8 and a backwash water inlet pipe 9 are provided on one side of the device body 21 below the filter bed 23; and the backwash air inlet pipe 8 is connected to a backwash fan 10, and the backwash water inlet pipe 9 is connected to the clean water tank 3 through a backwash pump 11. A water distribution pipe 18 and an aeration pipe 19 are provided in the device body below the filter bed 23, and the water distribution pipe 18 is connected to the backwash water inlet pipe 8, and the aeration pipe 19 is connected to the backwash air inlet pipe 9; and the water distribution pipe 18 is provided with a plurality of water distribution holes; and the aeration pipe 19 is provided with a plurality of aeration holes.

[0029] After a period of time, dirt, aged bacteria, etc. will adhere to the surface of the filler in the filter bed 23, which will reduce its denitrification capacity. Therefore, the filler needs to be backwashed regularly and stirred to ensure that the filler is fully utilized. In this embodiment, when the filtration cycle of the filter bed 23 exceeds 72 hours or the liquid level difference between the preset water distribution level and the actual liquid level in the device body 21 is less than 100 to 150 mm, and the backwashing liquid level standard is reached, backwashing is started.

[0030] When entering the backwash process, the backwash water enters the water distribution pipe 18 of the device body 21 through the backwash water inlet pipe 9, and the backwash fan 10 allows the backwash gas to enter the aeration pipe 19 in the device body 21 through the backwash air inlet pipe 8. The backwash water is evenly sprayed onto the filter bed 23 through the water distribution holes on the water distribution pipe 18, forming a reverse flow, flushing the impurities of the filler in the filter bed 23. At the same time, the backwash gas is released into the filter bed 23 through the aeration holes on the aeration pipe 19. The rising and bursting process of the bubbles cooperates with the flushing of the backwash water, which can stir the filler, thereby further loosening and taking away the impurities on the filter material, enhancing the backwash effect, making the filler fully utilized, and ensuring the denitrification effect. The backwash water is provided by the clear water tank 3 that stores the outlet water of the deep denitrification unit 2, which can realize the recycling of water resources and improve the utilization efficiency of water resources. In this embodiment, the backwash gas intensity is 10-17L / (m2·s), and the backwash water intensity is 8-11L / (m2·s).

[0031] A pressing plate 24 is provided in the device body 21, and the pressing plate 24 is located above the filter bed 23. The pressing plate 24 is provided with a plurality of mesh holes (not shown in the figure), and the mesh holes and the filter holes are smaller than the minimum particle size of the filler. By arranging the pressing plate 24 to cooperate with the filter plate 22, the filler moves between the pressing plate 24 and the filter plate 22 during flushing, which can prevent the filler of the filter bed 23 from being dispersed during backwashing and easily overflowing with the water flow.

[0032] Preferably, the sewage plant tailwater denitrification system further comprises a backwash water collection tank 12, and the backwash water collection tank 12 is connected to the backwash drain pipe 7 through a drain pump 13. The backwash water collection tank 12 is used to collect wastewater generated during the backwashing process. After the backwashing is completed, the wastewater containing these impurities and dirt will be discharged through the backwash drain pipe 7 and flow into the backwash water collection tank 12 for subsequent treatment or reuse.

[0033] The water distribution pipe 5 and the system outlet pipe 6 are both provided with a flow meter 14 and a TN detector (not shown in the figure). By real-time monitoring and adjusting the flow of inlet and outlet water and the TN content in the outlet water, the denitrification process can be controlled, and the denitrification effect of each denitrification reaction device can be tested, and each denitrification reaction device can be ensured to operate in the best state, which is convenient for improving or testing the denitrification efficiency of each denitrification reaction device, and at the same time ensuring that the outlet water quality meets the discharge standard or subsequent treatment requirements.

[0034] The water distribution pipe 5, the system water outlet pipe 6, the backwash air inlet pipe 9, the backwash water inlet pipe 8 and the backwash drain pipe 7 are respectively provided with valves 17. By providing the valves 17, each pipeline can be opened or closed, thereby realizing flexible control of the system operation.

[0035] The denitrification reaction device provided by the utility model adopts elemental sulfur, iron-carbon mixture and activated carbon as fillers to carry out denitrification treatment on tail water, and adopts a total water distribution tank 1 and a water distribution tank 4 to form two-stage uniform water distribution, does not need to add an external organic carbon source, and is not affected by the fluctuation of the organic matter content in the tail water. The denitrification efficiency can thus be reduced and the operation cost of the system can be guaranteed. The stability of the denitrification efficiency of the system.

[0036] The above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A sewage plant tailwater denitrification system, comprising a regulating water tank, a main water distribution tank, a deep denitrification unit and a clear water tank connected in sequence, characterized in that: The deep denitrification unit includes a plurality of denitrification reaction devices, each of which includes a device body, a distribution water tank is provided above the device body, each of the distribution water tanks is connected to the main distribution water tank through a water distribution pipe, and a system water outlet pipe is provided at the bottom of the device body, and the system water outlet pipe is connected to the clean water tank through a water outlet pump; A filter plate with a plurality of filter holes is provided in the body of the device, and a filter bed filled with elemental sulfur, an iron-carbon mixture and activated carbon as fillers is provided on the filter plate; a backwash drain pipe is provided on one side of the device body above the filter bed; a backwash air inlet pipe and a backwash water inlet pipe are provided on one side of the device body below the filter bed; and the backwash air inlet pipe is connected to a backwash fan, and the backwash water inlet pipe is connected to the clean water tank through a backwash pump.

2. A sewage plant tail water denitrification system according to claim 1, characterized in that: It also includes a backwash water collection tank, which is connected to the backwash drainage pipe through a drainage pump.

3. A sewage treatment plant tail water denitrification system according to claim 1, characterized in that: The water distribution pipe and the system water outlet pipe are both provided with flow meters and TN detectors.

4. A sewage plant tail water denitrification system according to claim 1, characterized in that: The water distribution pipes are provided with a pressure pump and a screw air compressor in sequence, and the screw air compressor is connected to an air storage tank.

5. A sewage plant tail water denitrification system according to claim 1, characterized in that: A pressing plate is arranged in the body of the device, and the pressing plate is located above the filter material bed. A plurality of mesh holes are arranged on the pressing plate, and the sizes of the mesh holes and the filter holes are smaller than the minimum particle size of the filler.

6. A sewage plant tail water denitrification system according to claim 1, characterized in that: Valves are respectively arranged on the water distribution pipe, the system water outlet pipe, the backwash air inlet pipe, the backwash water inlet pipe and the backwash drainage pipe.

7. A sewage plant tail water denitrification system according to claim 1, characterized in that: A water distribution pipe and an aeration pipe are arranged in the device body below the filter bed. The water distribution pipe is connected to the backwash water inlet pipe, and the aeration pipe is connected to the backwash air inlet pipe. The water distribution pipe is provided with a plurality of water distribution holes. The aeration pipe is provided with a plurality of aeration holes.

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