Anaerobic-aerobic coupling sewage treatment system

Abstract

The utility model belongs to the technical field of sewage purification, and particularly discloses an anaerobic-aerobic coupling sewage treatment system which comprises an anaerobic reaction tank, an anoxic reaction tank, an aerobic reaction tank, a secondary sedimentation tank and a clean water tank which are sequentially communicated, a water outlet end of the aerobic reaction tank is connected with a first return pipeline, and the first return pipeline is communicated with a water inlet end of the anoxic reaction tank; a first reflux pump is arranged on the first reflux pipeline; the secondary sedimentation tank is communicated with a second reflux pipeline, the second reflux pipeline is communicated with the water inlet end of the anaerobic reaction tank, a sludge concentration tank and a second reflux pump are arranged on the second reflux pipeline, and the sludge concentration tank is communicated with the sludge tank. According to the utility model, the second reflux pipeline is used for refluxing supernate obtained after sludge is compressed into the anaerobic reaction tank, so that the biodegradability of sewage is improved, and the first reflux pipeline is used for refluxing nitrate-containing mixed liquor into the anoxic reaction tank to be denitrified with an organic carbon source, so that the denitrification effect is achieved; and the ammonia nitrogen value can be degraded while organic matters are removed.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater purification technology, specifically relating to an anaerobic-aerobic coupled wastewater treatment system. Background Technology

[0002] Wastewater treatment refers to the process of removing or reducing pollutants in wastewater to a certain level to meet national or local discharge standards. Wastewater treatment is an important component of environmental protection, effectively reducing water pollution and protecting water resources.

[0003] Domestic sewage mainly contains the following substances: suspended solids: including feces, food residue, grease, paper scraps, etc.; organic matter: such as protein, carbohydrates, fats, etc.; nutrients such as nitrogen and phosphorus; pathogens: such as enteroviruses, coliform bacteria, etc.

[0004] Currently, the vast majority of urban wastewater treatment plants in my country use the traditional activated sludge process to treat urban domestic sewage. However, due to the relatively short sludge age of the traditional activated sludge process, it is not conducive to the accumulation of nitrifying bacteria with long generation cycles within the system. This results in poor denitrification performance of the traditional activated sludge process, and a large amount of nitrogenous compounds are discharged into natural water bodies without being effectively removed, causing eutrophication of the water bodies.

[0005] To address the poor nitrogen removal performance of existing wastewater treatment processes, it is necessary to improve the structure of the wastewater treatment system to solve the current technical problems. Utility Model Content

[0006] The purpose of this invention is to provide an anaerobic-aerobic coupled wastewater treatment system to improve the denitrification performance of the treatment system and enhance the wastewater treatment effect.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: an anaerobic-aerobic coupled wastewater treatment system, comprising an anaerobic reaction tank, an anoxic reaction tank, an aerobic reaction tank, a secondary sedimentation tank, and a clear water tank connected in sequence. The outlet of the aerobic reaction tank is connected to a first return pipeline, which is connected to the inlet of the anoxic reaction tank. A first return pump is installed on the first return pipeline. The secondary sedimentation tank is connected to a second return pipeline, which is connected to the inlet of the anaerobic reaction tank. A sludge thickening tank and a second return pump are sequentially installed along the media return path on the second return pipeline. The sludge thickening tank is connected to a sludge tank.

[0008] To better realize this utility model, the inlet end of the anaerobic reaction tank is connected to the sewage collection tank.

[0009] To better realize this utility model, the inlet of the sewage collection tank is equipped with a screw press, and the screw press is connected to a storage tank.

[0010] To better realize this utility model, a booster pump is provided at the outlet end of the sewage collection tank.

[0011] To better realize this utility model, the anoxic reaction tank is provided with a microbial carrier group, in which facultative anaerobic microorganisms are planted and cultivated; the aerobic reaction tank is also provided with a microbial carrier group, in which aerobic microorganisms are planted and cultivated.

[0012] To better realize this utility model, the sewage treatment system also includes an aerator, which has two sets of aerators, and the two sets of aerators are respectively installed in the anoxic reaction tank and the aerobic reaction tank.

[0013] To better realize this utility model, the first return pipeline and the pipeline connecting the aerobic reaction tank to the secondary sedimentation tank are both equipped with a first control valve. The two first control valves are respectively located at the inlet end of the first return pump and the inlet end of the secondary sedimentation tank.

[0014] To better realize this utility model, the bottom of the secondary sedimentation tank is connected to a sludge collection hopper, and an air lifting device is provided between the sludge collection hopper and the sludge thickening tank.

[0015] To better realize this utility model, the sewage treatment system also includes an ozone generator and a heater, the heater being located at the bottom of the clear water tank and the ozone generator being connected to the bottom of the clear water tank.

[0016] Beneficial effects:

[0017] This invention recirculates the supernatant produced by compressing sludge in the secondary sedimentation tank back to the anaerobic reactor via a second return pipeline. Under anaerobic conditions, phosphorus is released by polyphosphate-accumulating bacteria, increasing the phosphorus concentration in the wastewater. Simultaneously, some NH3-N is removed through cell synthesis, leading to a decrease in both NH3-N and BOD concentrations in the wastewater. Furthermore, the anaerobic reactor utilizes anaerobic bacteria to hydrolyze, acidify, and methanate organic matter, removing larger molecular weight organics from the wastewater, improving its biodegradability, and facilitating subsequent aerobic treatment. Additionally, through the first... The return pipeline returns the mixed liquor discharged from the aerobic reaction tank to the anoxic reaction tank via the first return pump. It can utilize the nitrates brought in by the mixed liquor and the organic carbon source in the water discharged from the anaerobic reaction tank to carry out denitrification, reducing NO2-N and NO3-N in the influent to N2 to achieve denitrification. While removing organic matter, it also degrades ammonia nitrogen. It makes full use of the chemical characteristics of the wastewater generated in each treatment stage to repeatedly degrade the pollutants in the wastewater. The reaction efficiency is high and the wastewater treatment effect is good. The treated clean water and sludge can be directly discharged or utilized, which is scientific and environmentally friendly. Attached Figure Description

[0018] Figure 1 This is a structural diagram of the wastewater treatment system of this utility model.

[0019] In the diagram: 1. Anaerobic reactor; 2. Anoxic reactor; 3. Aerobic reactor; 4. Secondary sedimentation tank; 5. Clear water tank; 6. First return pipeline; 7. First return pump; 8. Second return pipeline; 9. Sludge thickening tank; 10. Second return pump; 11. Sludge tank; 12. Wastewater collection tank; 13. Screw press; 14. Storage tank; 15. Lift pump; 16. Microbial carrier group; 17. Aerator; 18. Aerator; 19. First control valve; 20. Sludge hopper; 21. Air lifting device; 22. Ozone generator; 23. Heater. Detailed Implementation

[0020] Example

[0021] like Figure 1 As shown, an anaerobic-aerobic coupled wastewater treatment system includes an anaerobic reactor 1, an anoxic reactor 2, an aerobic reactor 3, a secondary sedimentation tank 4, and a clear water tank 5 connected in sequence. The effluent end of the aerobic reactor 3 is connected to a first return pipe 6, which is connected to the influent end of the anoxic reactor 2. A first return pump 7 is installed on the first return pipe 6. The secondary sedimentation tank 4 is connected to a second return pipe 8, which is connected to the influent end of the anaerobic reactor 1. A sludge thickening tank 9 and a second return pump 10 are sequentially installed on the second return pipe 8 along the media return path. The sludge thickening tank 9 is connected to a sludge tank 11.

[0022] The working principle of this utility model can be summarized as follows:

[0023] Wastewater is first discharged into anaerobic reactor 1 for phosphorus release. The supernatant produced by compressing sludge in secondary sedimentation tank 4 is returned to anaerobic reactor 1 through the second return pipe 8. Under anaerobic conditions, phosphorus is released by polyphosphate-accumulating bacteria, increasing the phosphorus concentration in the wastewater. At the same time, some NH3-N is removed due to cell synthesis, resulting in a decrease in the NH3-N concentration and BOD concentration in the wastewater. In addition, the anaerobic bacteria in anaerobic reactor 1 hydrolyze, acidify, and methanate organic matter, removing larger molecular weight organic matter from the wastewater, improving the biodegradability of the wastewater, and facilitating subsequent aerobic treatment.

[0024] After undergoing anaerobic reaction, the wastewater is discharged into the anoxic reaction tank 2 through a pipeline. At the same time, the mixed liquor discharged from the aerobic reaction tank 3 is returned to the anoxic reaction tank 2 through the first return pump 7 and the first return pipeline 6. The nitrates brought in by the mixed liquor and the organic carbon source in the water discharged from the anaerobic reaction tank 1 undergo denitrification, reducing NO2-N and NO3-N in the influent to N2 to achieve denitrification. At the same time, the ammonia nitrogen value is degraded while removing organic matter.

[0025] After undergoing anoxic reaction, the wastewater is discharged into aerobic reaction tank 3 through pipes for further oxidation and decomposition. At the same time, the inorganic carbon source produced by the decomposition of organic matter or carbon dioxide in the air is used as a nutrient source to convert ammonia nitrogen (NH3-N) in the wastewater into NO2-N and NO3-N; phosphorus also decreases rapidly due to excessive uptake by polyphosphate-accumulating bacteria.

[0026] After the above-mentioned anaerobic, anoxic, and aerobic reactions, part of the mixed liquor is returned to the anoxic reaction tank 2 via the second return pipe 8 for denitrification, and part is discharged into the secondary sedimentation tank 4 for sedimentation and separation. The secondary sedimentation tank 4 is an important part of the activated sludge system. It is used to clarify the mixed liquor and recover and concentrate the activated sludge. Its effectiveness directly affects the effluent quality and the concentration of the returned sludge. After the wastewater settles in the secondary sedimentation tank 4, the upper clear water is discharged into the clear water tank 5, and the bottom sludge is discharged into the sludge thickening tank 9 for concentration. After concentration, the supernatant is returned to the anaerobic reaction tank 1 via the second return pump 10 and the second return pipe 8. The sludge is discharged into the sludge tank 11 for centralized treatment and can be used as a soil conditioner and organic fertilizer for soil fertilization.

[0027] Preferably, the inlet of the anaerobic reactor 1 is connected to the sewage collection tank 12. Since the water quality and quantity vary at different times, the peak flow rate is generally 2 to 8 times the average treatment capacity. Therefore, by designing the sewage collection tank 12, the sewage treatment system can operate continuously and stably, while regulating the water quantity and homogenizing the water quality.

[0028] Preferably, the inlet of the sewage collection tank 12 is equipped with a screw press 13, which is connected to a storage tank 14. The screw press 13 intercepts and lifts large-sized solids to the external storage tank 14 for centralized processing, which can improve the efficiency of subsequent processing.

[0029] Preferably, the outlet end of the sewage collection tank 12 is equipped with a lift pump 15, which ensures the stability of the treated water volume in each subsequent reaction tank by setting the lift pump 15.

[0030] Preferably, the anoxic reaction tank 2 is equipped with a microbial carrier group 16 in which facultative anaerobic microorganisms are cultivated, and the aerobic reaction tank 3 is equipped with a microbial carrier group 16 in which aerobic microorganisms are cultivated. The microbial carrier group 16 prevents the loss of microbial communities, maintains stable microbial community structure, and has high efficiency in treating organic matter. The microbial carrier group 16 is used semi-permanently and does not need to be replaced. Usually, after the system has been running for 3 to 5 years, only a small amount needs to be replenished annually as appropriate. The microbial carrier group 16 is semi-suspended in water, which increases the contact area between the gas, liquid, and solid phases, thereby improving the efficiency of wastewater treatment.

[0031] Preferably, the wastewater treatment system further includes an aerator 17, which has two sets of aerators 18. The two sets of aerators 18 are respectively installed in the anoxic reaction tank 2 and the aerobic reaction tank 3. By setting up the aeration device, the wastewater is filled with fine and dense oxygen, which has a high oxygen dissolution rate and can effectively promote the decomposition of aerobic and facultative anaerobic microorganisms.

[0032] Preferably, both the first return pipeline 6 and the pipeline connecting the aerobic reaction tank 3 to the secondary sedimentation tank 4 are equipped with a first control valve 19. The two first control valves 19 are respectively located at the inlet end of the first return pump 7 and the inlet end of the secondary sedimentation tank 4. The flow rate of the mixed liquor returning to the anoxic reaction tank 2 is controlled by the two first control valves 19 to ensure that the nitrates introduced into the mixed liquor and the organic carbon source in the water discharged from the anaerobic reaction tank 1 reach the optimal reaction ratio, thereby obtaining an optimal denitrification effect.

[0033] Preferably, the bottom of the secondary sedimentation tank 4 is connected to a sludge collection hopper 20, and an air-lift device 21 is provided between the sludge collection hopper 20 and the sludge thickening tank 9. The sludge collection hopper 20 and the air-lift device 21 can improve the rate of sludge removal in the secondary sedimentation tank 4, ensure that the secondary sedimentation tank 4 always has a large storage capacity, and enable the wastewater after each stage of the preceding reaction to be continuously transported to the secondary sedimentation tank 4 for sedimentation and separation, which is beneficial to improving the treatment efficiency of the entire treatment system.

[0034] Preferably, the wastewater treatment system further includes an ozone generator 22 and a heater 23. The heater 23 is located at the bottom of the clear water tank 5, and the ozone generator 22 is connected to the bottom of the clear water tank 5. The heater 23 can prevent the tank from freezing in winter, ensuring that the tank always has sufficient capacity, so that the entire system can still operate normally even in winter. By using ozone to enter the bottom of the clear water tank 5 and react fully with the clear water, it can disinfect and sterilize, and also remove some COD.

[0035] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. An anaerobic-aerobic coupled wastewater treatment system, characterized in that, The system includes an anaerobic reactor (1), an anoxic reactor (2), an aerobic reactor (3), a secondary sedimentation tank (4), and a clear water tank (5) connected in sequence. The outlet of the aerobic reactor (3) is connected to a first return pipeline (6), which is connected to the inlet of the anoxic reactor (2). A first return pump (7) is installed on the first return pipeline (6). The secondary sedimentation tank (4) is connected to a second return pipeline (8), which is connected to the inlet of the anaerobic reactor (1). A sludge thickening tank (9) and a second return pump (10) are installed in sequence along the medium return path on the second return pipeline (8). The sludge thickening tank (9) is connected to a sludge tank (11).

2. The anaerobic-aerobic coupled wastewater treatment system according to claim 1, characterized in that, The inlet of the anaerobic reactor (1) is connected to the sewage collection tank (12).

3. The anaerobic-aerobic coupled wastewater treatment system according to claim 2, characterized in that, The sewage collection tank (12) is equipped with a screw press (13) at the water inlet end, and the screw press (13) is connected to a storage tank (14).

4. The anaerobic-aerobic coupled wastewater treatment system according to claim 2, characterized in that, The sewage collection tank (12) is equipped with a booster pump (15) at its outlet.

5. The anaerobic-aerobic coupled wastewater treatment system according to claim 1, characterized in that, The anoxic reaction tank (2) is equipped with a microbial carrier group (16), in which facultative anaerobic microorganisms are planted and cultivated; the aerobic reaction tank (3) is also equipped with a microbial carrier group (16), in which aerobic microorganisms are planted and cultivated.

6. The anaerobic-aerobic coupled wastewater treatment system according to claim 1, characterized in that, The wastewater treatment system also includes an aerator (17), which has two sets of aerators (18), which are respectively installed in the anoxic reaction tank (2) and the aerobic reaction tank (3).

7. The anaerobic-aerobic coupled wastewater treatment system according to claim 1, characterized in that, The first return pipeline (6) and the pipeline connecting the aerobic reaction tank (3) to the secondary sedimentation tank (4) are both equipped with a first control valve (19). The two first control valves (19) are respectively located at the inlet end of the first return pump (7) and the inlet end of the secondary sedimentation tank (4).

8. The anaerobic-aerobic coupled wastewater treatment system according to claim 1, characterized in that, The bottom of the secondary sedimentation tank (4) is connected to a sludge collection hopper (20), and an air-lift device (21) is provided between the sludge collection hopper (20) and the sludge thickening tank (9).

9. The anaerobic-aerobic coupled wastewater treatment system according to claim 1, characterized in that, The wastewater treatment system also includes an ozone generator (22) and a heater (23), the heater (23) being located at the bottom of the clear water tank (5) and the ozone generator (22) being connected to the bottom of the clear water tank (5).

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