Urban sewage advanced denitrification and dephosphorization device and urban sewage purification system

Abstract

The utility model relates to resource purification technical field especially, and more particularly to a kind of device and urban sewage purification system of urban sewage advanced denitrification and phosphorus removal, and urban sewage advanced denitrification and phosphorus removal device includes: sequentially connected raw water tank, oxygen zone, secondary sedimentation tank, regulating basin, anoxic zone, chemical phosphorus removal unit;Anaerobic ammonia oxidation biological membrane filler or granular sludge is equipped in anoxic zone.This application provides urban sewage advanced denitrification and phosphorus removal device in front of nitrification tank setting high-speed activated sludge tank, high-speed activated sludge tank can realize carbon source recovery and improve nitrification reaction rate, reduce aeration energy consumption, thereby reduce energy consumption, improve processing efficiency, in addition, anaerobic ammonia oxidation bacteria in anoxic zone can remove ammonia nitrogen and nitrate simultaneously, with energy saving, efficient, convenient, stable characteristics, reduce the process requirement to antecedent oxygen section, improve the convenience and stability of system.

Description

Technical Field

[0001] This application relates to the field of resource purification technology, and in particular to a device and system for deep denitrification and phosphorus removal of urban sewage. Background Technology

[0002] The high levels of nitrogen and phosphorus in urban wastewater not only affect water quality but also trigger a series of environmental problems, such as eutrophication, algal blooms, and water quality deterioration, ultimately threatening ecosystems and human health. Therefore, nitrogen and phosphorus removal has become a key objective of urban wastewater treatment.

[0003] Although nitrification-denitrification processes and their derivatives based on the traditional activated sludge process (CAS) dominate current urban wastewater treatment, they also have some significant limitations, such as high energy and material consumption and complex operational requirements. Therefore, developing new wastewater treatment technologies that are more economical, efficient, and resource-efficient is urgently needed to meet increasingly stringent environmental requirements and the challenges of sustainable development in the future. Utility Model Content

[0004] In view of this, the purpose of this utility model is to provide a device and a system for deep denitrification and phosphorus removal of urban sewage.

[0005] In a first aspect, this utility model provides a device for deep nitrogen and phosphorus removal from urban sewage. The device includes: a raw water tank, an aerobic zone, a secondary sedimentation tank, an equalization tank, an anoxic zone, and a chemical phosphorus removal unit connected in sequence; the aerobic zone includes a high-speed activated sludge tank and a nitrification tank connected in sequence; the connecting pipeline between the secondary sedimentation tank and the equalization tank is also connected to the outlet of the fermentation unit; the anoxic zone is equipped with anaerobic ammonia oxidation biofilm packing or granular sludge.

[0006] In conjunction with the first aspect, both the high-speed activated sludge tank and the nitrification tank are equipped with aeration devices; the high-speed activated sludge tank is also connected to the secondary sedimentation tank.

[0007] In conjunction with the first aspect, the device also includes: a thickening tank and a fermentation unit; the high-speed activated sludge tank is also sequentially connected to the thickening tank, the fermentation unit, the equalization tank, and the anoxic zone.

[0008] In conjunction with the first aspect, the fermentation unit is also sequentially connected to the digestion unit, the sludge dewatering unit, and / or the biogas power generation unit.

[0009] In conjunction with the first aspect, the device also includes an iron salt dosing device, which is connected to the digestion unit and the chemical phosphorus removal unit, respectively.

[0010] In conjunction with the first aspect, the chemical phosphorus removal unit includes a mixing tank, a flocculation tank, and a sedimentation tank connected in sequence; the sedimentation tank is also connected to the iron and phosphorus recovery unit.

[0011] In conjunction with the first aspect, agitators are installed in the high-speed activated sludge tank, equalization tank, anoxic zone, mixing tank, and flocculation tank.

[0012] In conjunction with the first aspect, water quality analyzers are installed in the high-speed activated sludge tank, nitrification tank, equalization tank, anoxic zone, and sedimentation tank.

[0013] In conjunction with the first aspect, the pH adjustment unit is located within the adjustment tank, sedimentation tank, fermentation unit, and digestion unit.

[0014] Secondly, this utility model embodiment also provides an urban sewage purification system, including the device for deep denitrification and phosphorus removal of urban sewage as described above.

[0015] The present invention provides the following beneficial effects: This application provides a device for deep denitrification and phosphorus removal of urban sewage and an urban sewage purification system. The device for deep denitrification and phosphorus removal of urban sewage includes: a raw water tank, an aerobic zone, a secondary sedimentation tank, an equalization tank, an anoxic zone, and a chemical phosphorus removal unit connected in sequence; the anoxic zone is provided with anaerobic ammonia oxidation biofilm packing or granular sludge.

[0016] The device for deep nitrogen and phosphorus removal in urban wastewater provided in this application is equipped with a high-speed activated sludge tank before the nitrification tank. The high-speed activated sludge tank can realize carbon source recovery and improve the nitrification reaction rate, reduce aeration energy consumption, thereby reducing energy consumption and improving treatment efficiency. In addition, the anaerobic ammonia oxidizing bacteria in the anoxic zone can simultaneously remove ammonia nitrogen and nitrate, which has the characteristics of energy saving, high efficiency, convenience and stability, reduces the process requirements of the preceding aerobic section, and improves the convenience and stability of the system.

[0017] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of this invention are realized and obtained through the structures particularly pointed out in the description, claims, and drawings.

[0018] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of this application or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1This application provides a schematic diagram of the structure of an apparatus for deep nitrogen and phosphorus removal from urban wastewater.

[0021] The attached figures are labeled as follows: 1-Raw water tank, 2-Secondary sedimentation tank, 3-Equalization tank, 4-Anoxic zone, 5-Chemical phosphorus removal unit, 6-High-speed activated sludge tank, 7-Nitrification tank, 8-Fermentation unit, 9-Thickening tank, 10-Digestion unit, 11-Sludge dewatering unit, 12-Biogas power generation unit, 13-Iron salt dosing device, 14-Iron and phosphorus recovery unit. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] To facilitate understanding of this embodiment, the technical terms used in this application will be briefly introduced below.

[0024] The A / O process (Anoxic / Oxic) is an improved activated sludge process that achieves biological denitrification through a two-stage series reaction of anoxic and aerobic reactions, characterized by its simple process flow. The core principle of this process is pre-denitrification: in the anoxic stage, heterotrophic bacteria hydrolyze suspended pollutants such as starch, fiber, and carbohydrates, as well as soluble organic matter in the wastewater, into organic acids; in the aerobic stage, nitrification removes ammonia nitrogen (…). ) is converted into nitrate ( Then, the mixed liquor is refluxed back to the anoxic zone to complete denitrification. It is converted into nitrogen gas (N2).

[0025] After introducing the technical terms used in this application, the application scenarios and design concepts of the embodiments of this application will be briefly described below.

[0026] Traditional activated sludge processes (CAS) involving nitrification and denitrification, along with their derivatives, also have significant limitations: First, their nitrogen and phosphorus removal efficiency is poor, with nitrogen removal efficiency at only 70%-80% and phosphorus removal efficiency even lower at 20%-30%. Second, their nitrogen removal efficiency is strictly limited by the nitrification liquor recirculation ratio (typically 200%-400%), resulting in high energy consumption. Furthermore, their system has weak resistance to shock loads, and fluctuations in influent water quality easily affect the stability of treatment performance. These factors collectively restrict the application effectiveness of this process under scenarios with high emission standards.

[0027] Based on this, this application provides an apparatus for deep denitrification and phosphorus removal of urban sewage and an urban sewage purification system.

[0028] Example 1 This application provides a device for deep nitrogen and phosphorus removal from urban wastewater, combined with Figure 1 As shown, the device includes: a raw water tank 1, an aerobic zone, a secondary sedimentation tank 2, an equalization tank 3, an anoxic zone 4, and a chemical phosphorus removal unit 5 connected in sequence; the aerobic zone includes a high-speed activated sludge tank 6 and a nitrification tank 7 connected in sequence; the connecting pipeline between the secondary sedimentation tank 2 and the equalization tank 3 is also connected to the outlet of the fermentation unit 8; the anoxic zone 4 is equipped with anaerobic ammonia oxidation biofilm packing or granular sludge.

[0029] The device for deep nitrogen and phosphorus removal from urban wastewater provided in this application achieves efficient nitrogen and phosphorus removal and resource recovery from urban wastewater by coupling sludge fermentation, anaerobic ammonia oxidation, and chemical phosphorus removal processes. Positioning the secondary sedimentation tank 2 between the aerobic zone and the anoxic zone 4 blocks the flow of sludge between the aerobic zone and the anoxic zone 4, avoiding microbial competition caused by sludge mixing. This ensures the biological activity and abundance of functional bacteria (i.e., anaerobic ammonia-oxidizing bacteria) in the anoxic zone 4, which is beneficial for maintaining the stability of the microbial system and nitrogen removal efficiency in the anoxic zone 4.

[0030] In conjunction with the first aspect, both the high-speed activated sludge tank 6 and the nitrification tank 7 are equipped with aeration devices (not shown in the figure); the high-speed activated sludge tank 6 is also connected to the secondary sedimentation tank 2, where solid arrows represent the direction of liquid flow, dashed arrows represent the direction of sludge flow, and dotted dashed arrows represent the direction of gas flow.

[0031] Urban wastewater is introduced into the aerobic zone (O section), where it undergoes rapid adsorption of organic matter into the sludge phase in a high-speed activated sludge tank (HRAS), simultaneously reducing the load on the subsequent nitrification tank. Afterwards, it is introduced into the nitrification tank to remove ammonia nitrogen. ) oxidized to nitrate nitrogen ( -N). The effluent from the nitrification tank enters the secondary sedimentation tank 2, where sludge and water are separated through sedimentation. The supernatant is mixed and optimized in the equalization tank before entering the anoxic zone, while the bottom sludge is returned to the high-speed activated sludge tank. The sludge concentration in the aerobic zone is maintained at 1500-3000 mg / L through sludge return.

[0032] Subsequently, the effluent from the secondary sedimentation tank 2 and the fermentation liquid produced by the fermentation unit 8 are fed into the equalization tank to adjust and optimize the water quality parameters (pH 7.27-7.29, C / N 1.14-2.14).

[0033] After water quality conditioning, the mixed liquor is introduced into the anoxic zone (Section A). Anoxic zone 4 is filled with anaerobic ammonia oxidation biofilm packing or granular sludge, where a short-cut nitrate dissimilatory reduction to ammonium coupled with anaerobic ammonia oxidation (PDNRA-Anammox) reaction occurs. Anaerobic ammonia oxidizing bacteria first utilize an organic carbon source as a reducing agent, converting nitrate nitrogen in the raw water into the intermediate product nitrite nitrogen via the PDNRA reaction. Subsequently, the ammonia nitrogen in the raw water and the generated nitrite nitrogen are converted into nitrogen gas via the Anammox reaction. Therefore, anaerobic ammonia oxidizing bacteria can be coupled with nitrifying bacteria to achieve nitrogen removal through a more efficient, convenient, and stable full-process nitrification-short-cut nitrate dissimilatory reduction to ammonium coupled with anaerobic ammonia oxidation (Nitrification-PDNRA-Anammox) process.

[0034] The solution is then introduced into chemical phosphorus removal unit 5 for phosphorus removal. Chemical phosphorus removal unit 5 includes a mixing tank, a flocculation tank, and a sedimentation tank connected in sequence. The mixing tank is connected to the iron salt dosing device, and its main function is to ensure rapid and uniform distribution of the reagent in the water, promoting the initiation of the chemical reaction. Key parameters are: molar ratio of added iron salt to total phosphorus in the wastewater: 1.5-3.0; retention time: 30-60 seconds; mixing intensity (G value): 700-1000 s. -1 .

[0035] The main function of the flocculation tank is to ensure the full reaction of the reagents and phosphates, forming larger flocs. Key parameters are: hydraulic retention time: 15-30 minutes; stirring intensity (G-value): 20-60 s. -1 .

[0036] The main function of the sedimentation tank is to separate the formed phosphate flocs by gravity settling, and the resulting precipitate is sent to the iron and phosphorus recovery unit 14. Surface loading: 8-12 m 3 / (m 2 ·h), sedimentation zone water depth: 3-5 m.

[0037] The inclusion of chemical phosphorus removal unit 5 not only improves effluent quality but also makes the operation of the high-speed activated sludge tank more flexible. While high-speed activated sludge systems with short sludge ages generally achieve good removal efficiency, maintaining above 90%, this high removal rate relies on a high HRT (Heat Retention Time). Extending the HRT, while improving wastewater treatment efficiency, also increases energy consumption during the treatment process, contradicting the initial goal of energy saving and efficiency improvement with short sludge ages. Clearly, the inclusion of a chemical phosphorus removal unit helps realize the true effectiveness of short-sludge-age activated sludge systems.

[0038] In conjunction with the first aspect, agitators are installed in the high-speed activated sludge tank 6, the equalization tank 3, the anoxic zone 4, the mixing tank, and the flocculation tank.

[0039] In the high-speed activated sludge tank 6, corrosion-resistant paddle or turbine agitators can be used to agitate the incoming municipal sewage to promote thorough mixing of sludge and sewage, prevent sedimentation, and ensure efficient transfer of organic matter to the sludge phase.

[0040] A low-speed propeller-type agitator can be used in the equalization tank 3, equipped with online pH / COD monitoring and linkage control, to uniformly mix the effluent from the secondary sedimentation tank 2 and the fermentation liquid, optimize water quality (pH, C / N ratio), and prevent short-circuiting.

[0041] In anoxic zone 4, a submersible mixer with a low shear force design can be used to maintain the fluidization state of the anaerobic ammonia oxidation packing / granular sludge, ensuring full contact between the substrate and microorganisms.

[0042] In the mixing tank of the chemical phosphorus removal unit 5, a chemically resistant static mixer or a high-speed turbine agitator can be used to rapidly disperse iron salts and promote phosphorus removal. and The reaction produces ferric phosphate flocs.

[0043] The flocculation tank in the chemical phosphorus removal unit 5 can be equipped with a paddle-type agitator with adjustable speed. Gentle stirring causes the tiny flocs to coagulate into larger, settleable particles, preventing the flocs from breaking. In conjunction with the first aspect, the device also includes: a thickening tank 9 and a fermentation unit 8; the high-speed activated sludge tank 6 is also sequentially connected to the thickening tank 9, the fermentation unit 8, the equalization tank 3 and the anoxic zone 4.

[0044] The sludge in the high-speed activated sludge tank 6 is fed into the thickening tank 9 for thickening treatment. The concentrated liquid is then returned to the high-speed activated sludge tank 6 to obtain concentrated sludge with a water content of 90%-95%. Subsequently, the concentrated sludge is fed into the fermentation unit 8 for anaerobic fermentation to obtain fermentation products. The fermentation liquid in the fermentation products is fed into the equalization tank 3.

[0045] The operating parameters of fermentation unit 8 are: pH 7.0-11.0, temperature 25-35℃ (mesophilic fermentation), and residence time 7-11 days. It is used for concentrated sludge fermentation, yielding fermentation broth and residual fermentation products. The fermentation broth mainly contains volatile fatty acids (VFAs) and ammonia nitrogen (…). The remaining fermentation products consist of recalcitrant organic matter and inert substances.

[0046] The amount of fermentation broth added is dynamically adjusted based on the C / N ratio of the influent to the equalization tank. In this embodiment, the target C / N ratio is 1.14-2.14. During this process, the fermentation broth provides the required carbon source, replacing traditional exogenous carbon (such as methanol), reducing operating costs. Ammonia nitrogen is used to supplement the effluent from the nitrification tank, maintaining the substrate balance for the denitrification reaction.

[0047] The conditioning solution is then introduced into anoxic zone 4, which is filled with anaerobic ammonia oxidation biofilm packing or granular sludge. The biological reaction by which anaerobic ammonia oxidation bacteria simultaneously remove ammonia nitrogen and nitrate is a short-cut nitrate dissimilatory reduction to ammonium coupled with anaerobic ammonia oxidation (PDNRA - Anammox) reaction. This process includes two steps: first, anaerobic ammonia oxidation bacteria use an organic carbon source as a reducing agent to convert nitrate nitrogen in the raw water into the intermediate product nitrite nitrogen through the PDNRA reaction; then, through the Anammox reaction, they convert ammonia nitrogen in the raw water and the generated nitrite nitrogen into nitrogen gas. This process eliminates the need to consider bacterial community competition, resulting in a more stable microbial community structure and significantly reducing the maintenance difficulty of the O-section.

[0048] In conjunction with the first aspect, the fermentation unit 8 is also sequentially connected to the digestion unit 10, the sludge dewatering unit 11, and / or the biogas power generation unit 12.

[0049] The remaining fermentation products are fed into the digestion unit 10 for digestion treatment to obtain digestion gas and digested sludge; the digestion gas is fed into the biogas power generation unit 12, and the generated electricity is then sent to the urban sewage treatment system; at the same time, the digested sludge is fed into the sludge dewatering unit 11 for dewatering treatment, and the dewatered liquid is sent to the high-speed activated sludge tank 6.

[0050] The operating parameters of the digestion unit 10 are as follows: temperature controlled at 35-40℃ (mesophilic digestion, suitable for methanogen activity), pH controlled at 6.8-7.5 (to maintain the optimal environment for methanogens), iron salt addition requirements: maintaining an iron concentration of 2-50 mM through the iron salt addition device 13 (to inhibit hydrogen sulfide generation and improve methane purity), sludge dosing rate controlled at 5%-12% (to balance organic load and digestion efficiency), and retention time controlled at 5-18 days (to ensure sufficient degradation of organic matter). The resulting digestion products include digested gas and digested sludge. The digested gas includes 60%-70% methane and a small amount of... , (Purification treatment is required); the digested sludge has a water content of 95%-98% and contains recalcitrant organic matter and inert substances.

[0051] The biogas power generation unit 12 mainly focuses on gas purification, power generation, and energy recovery. Specifically, it removes pollutants through activated carbon adsorption. (For example, to When the concentration drops to <50 ppm, the gas generator converts methane into electricity (conversion efficiency ≥35%), and the waste heat is used for system heating; the electricity is delivered to aeration devices, agitators and other equipment, and the heat is used to maintain the temperature of the digestion unit.

[0052] Simultaneously, sludge dewatering is performed using centrifugal dewatering or plate and frame filter press to reduce the moisture content of the digested sludge to 30%-80%; and dewatering liquid treatment is carried out to remove dissolved COD from the dewatering liquid. The sludge is returned to the high-velocity activated sludge tank (HRAS) to replenish the carbon source and maintain the activity of microorganisms.

[0053] The above steps enable a closed loop of carbon source-energy: the residual organic waste generated during the fermentation process is anaerobically digested and converted into methane-rich digestive gas; this gas is then used to generate electricity or heat, and the generated electricity and heat directly supply the system's own operating needs, thereby significantly reducing dependence on external electricity and procurement costs, and realizing internal recycling and self-sufficiency of energy.

[0054] It can also reduce sludge volume: after sludge is concentrated, fermented, digested and dewatered, the final dry solids volume is reduced by 60%-80%.

[0055] In conjunction with the first aspect, the device also includes an iron salt dosing device 13, which is connected to the digestion unit 10 and the chemical phosphorus removal unit 5, respectively.

[0056] The iron salt dosing device 13 stores an iron salt solution (such as iron salt solution). , Equipped with a level gauge and corrosion-resistant lining, the iron salt dosing device 13 is connected to the digestion unit 10 to add iron salt (concentration of 2-50 mM) to the digestion tank to inhibit... Generates and promotes phosphorus release, specifically, With sulfides ( The reaction produces FeS precipitate, reducing the amount of FeS in biogas. Content (<50ppm), improving methane purity; iron salt dosing device 13 is connected to chemical phosphorus removal unit 5 to add iron salt to the mixing tank in chemical phosphorus removal unit 5 for phosphate precipitation, specifically and generate Precipitation achieves deep phosphorus removal.

[0057] In conjunction with the first aspect, the chemical phosphorus removal unit 5 includes a mixing tank, a flocculation tank, and a sedimentation tank connected in sequence; the sedimentation tank is also connected to the iron and phosphorus recovery unit 14.

[0058] The mixing tank is used for rapid mixing of iron salts ( ) and phosphorus-containing wastewater, initiate a chemical precipitation reaction, and the flocculation tank is used to promote the precipitation of small amounts of iron phosphate ( ). The flocs aggregate into large, settleable particles; the sedimentation tank is used to separate the ferric phosphate flocs by gravity settling, achieving mud-water separation. The bottom of the sedimentation tank contains... The sludge is then subjected to iron and phosphorus recovery, which can be achieved by using sulfuric acid (…). Dissolves (pH≤2) ,release and Add calcium salts (such as calcium salts) ) to generate calcium phosphate ( Precipitation, used as a raw material for phosphate fertilizer; pH adjusted to neutral. by The iron sludge (iron-phosphorus precipitate) is precipitated and reused in the iron salt dosing device. This forms a resource recycling chain: through chemical phosphorus removal by adding iron salt, the iron-containing sludge (iron-phosphorus precipitate) is effectively recovered and regenerated into reusable iron salt. This closed-loop design significantly reduces dependence on external iron salt reagents and realizes the recycling of iron within the system, thereby reducing reagent costs by 30%-40%.

[0059] In conjunction with the first aspect, water quality analyzers are installed in the high-speed activated sludge tank 6, nitrification tank 7, equalization tank 3, anoxic zone 4, and sedimentation tank.

[0060] Water quality is measured in the high-speed activated sludge tank 6, nitrification tank 7, equalization tank 3, anoxic zone 4 and sedimentation tank by setting up water quality instruments. The measured water quality parameters include at least: DO, COD, nitrogen ion content and iron ion content.

[0061] In conjunction with the first aspect, the pH adjustment unit is located within the adjustment tank 3, sedimentation tank, fermentation unit 8, and digestion unit 10.

[0062] pH adjustment units are added to the equalization tank 3, sedimentation tank, fermentation unit 8 and digestion unit 10 where pH control is required, for pH adjustment.

[0063] Secondly, this utility model embodiment also provides an urban sewage purification system, including the device for deep denitrification and phosphorus removal of urban sewage as described above.

[0064] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system and apparatus described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0065] Furthermore, in the description of the embodiments of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0066] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0067] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0068] Finally, it should be noted that the above embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A device for deep nitrogen and phosphorus removal from urban wastewater, characterized in that, The device includes: a raw water tank, an aerobic zone, a secondary sedimentation tank, an equalization tank, an anoxic zone, and a chemical phosphorus removal unit connected in sequence; the aerobic zone includes a high-speed activated sludge tank and a nitrification tank connected in sequence; the connecting pipeline between the secondary sedimentation tank and the equalization tank is also connected to the outlet of the fermentation unit; the anoxic zone is equipped with anaerobic ammonia oxidation biofilm packing or granular sludge.

2. The apparatus according to claim 1, characterized in that, Both the high-speed activated sludge tank and the nitrification tank are equipped with aeration devices; the high-speed activated sludge tank is also connected to the secondary sedimentation tank.

3. The apparatus according to claim 1, characterized in that, The device also includes: a thickening tank and a fermentation unit; the high-speed activated sludge tank is also sequentially connected to the thickening tank, the fermentation unit, the equalization tank, and the anoxic zone.

4. The apparatus according to claim 3, characterized in that, The fermentation unit is also sequentially connected to the digestion unit, the sludge dewatering unit, and / or the biogas power generation unit.

5. The apparatus according to claim 4, characterized in that, The device also includes an iron salt dosing device, which is connected to the digestion unit and the chemical phosphorus removal unit, respectively.

6. The apparatus according to claim 1, characterized in that, The chemical phosphorus removal unit includes a mixing tank, a flocculation tank, and a sedimentation tank connected in sequence; the sedimentation tank is also connected to the iron and phosphorus recovery unit.

7. The apparatus according to claim 6, characterized in that, Agitators are installed in the high-speed activated sludge tank, the equalization tank, the anoxic zone, the mixing tank, and the flocculation tank, respectively.

8. The apparatus according to claim 7, characterized in that, Water quality analyzers are installed in the high-speed activated sludge tank, the nitrification tank, the equalization tank, the anoxic zone, and the sedimentation tank, respectively.

9. The apparatus according to claim 5, characterized in that, The pH adjustment unit is located within the adjustment tank, sedimentation tank, fermentation unit, and digestion unit.

10. A city wastewater purification system, characterized in that, Includes the apparatus for deep nitrogen and phosphorus removal from urban wastewater as described in any one of claims 1-9.

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