Advanced sewage treatment system

Abstract

The utility model provides an advanced sewage treatment system. The advanced sewage treatment system comprises an anaerobic tank, an anoxic tank, an aerobic tank, a sedimentation tank and an autotrophic nitrogen removal filter tank which are connected in sequence, wherein the anaerobic tank is connected with the water inlet pump; the autotrophic nitrogen removal filter tank comprises a plurality of partitioned filter tanks which are arranged in parallel, a supporting layer and a sulfur autotrophic carrier filler layer are arranged in the middle of each partitioned filter tank, a water inlet and a backwashing water outlet of each partitioned filter tank are positioned above the sulfur autotrophic carrier filler layer, and a water outlet of each partitioned filter tank is positioned below the corresponding supporting layer; the liquid level meter, the backwashing water pump and the aeration fan are connected with the controller; a liquid level meter is arranged in each partitioned filter tank; and the lower part of the supporting layer of each partitioned filter tank is connected with a backwashing water pump and the outlet end of an aeration fan. According to the system, heterotrophic denitrification and autotrophic denitrification are integrated, a carbon source does not need to be added, COD, ammonia nitrogen, TN, TP and SS can be synchronously removed, and the effluent quality is guaranteed; and the device can adapt to different sewage treatment capacity requirements, and realizes low-energy-consumption and continuous and efficient sewage treatment.

Description

Technical Field

[0001] The utility model belongs to the technical field of sewage treatment, and specifically relates to a sewage deep treatment system. Background Art

[0002] In the process of urban domestic sewage treatment, heterotrophic denitrification technology is often used for denitrification. The heterotrophic denitrification process is that denitrifying bacteria consume organic matter as electron donors under anoxic or anaerobic conditions to convert nitrate (NO 3- ) is reduced to nitrogen gas. In the sewage treatment process, there is often a lack of carbon source (organic matter) in the wastewater. The existing heterotrophic denitrification sewage treatment system needs to add additional carbon source to ensure the denitrification effect of the heterotrophic denitrification process, but the additional addition of carbon source increases the cost of sewage treatment and increases the amount of sludge. The existing improved technical solution can effectively solve the problem of insufficient carbon source by adding autotrophic denitrification carriers to the anoxic tank or anaerobic tank to form a synergistic form of heterotrophic denitrification and autotrophic denitrification. However, there is a problem that the autotrophic bacteria are inhibited by the growth of heterotrophic bacteria, resulting in difficulty in growth and reproduction. The sewage treatment speed is slow, and the operation and maintenance are difficult, which affects the sewage treatment efficiency. Utility Model Content

[0003] In view of the defects of the above-mentioned prior art, the utility model provides a sewage deep treatment system, which integrates heterotrophic and autotrophic denitrification to achieve deep denitrification and filtration treatment, does not require the addition of a carbon source, can simultaneously remove COD, ammonia nitrogen, TN, TP and SS, and effectively ensures the quality of effluent; can adapt to different sewage treatment volume requirements, and achieve low-energy operation and continuous and efficient sewage treatment.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0005] A sewage deep treatment system, comprising an anaerobic tank, an anoxic tank, an aerobic tank, a sedimentation tank and an autotrophic denitrification filter tank connected in sequence;

[0006] Wherein, the anaerobic tank is connected to the outlet end of the water inlet pump;

[0007] The autotrophic denitrification filter tank comprises a plurality of grid filter tanks arranged in parallel, each of the grid filter tanks is provided with a support layer and a sulfur autotrophic carrier filler layer in the middle, the water inlet and backwash outlet of the grid filter tank are located above the sulfur autotrophic carrier filler layer, and the water outlet is located below the support layer;

[0008] It also includes a controller and a liquid level meter, a backwash water pump, and an aeration fan connected to the controller; each of the grid filter tanks is provided with the liquid level meter; and the supporting layer in each of the grid filter tanks is connected to the outlet ends of the backwash water pump and the aeration fan.

[0009] In one embodiment of the present application, a magnetic precipitation device is also included, and the magnetic precipitation device is connected to the water outlet of each of the grid filter tanks.

[0010] In one embodiment of the present application, a water distributor is provided at the bottom of each of the grid filter tanks, and each of the water distributors is connected to the backwash water pump.

[0011] In one embodiment of the present application, a first air distribution pipe is provided at the bottom of each of the grid filter tanks, and each of the first air distribution pipes is connected to the aeration fan.

[0012] In one embodiment of the present application, a second air distribution pipe is provided at the bottom of the aerobic tank, and the second air distribution pipe is connected to the aeration fan via a pipeline;

[0013] A third air distribution pipe is provided at the bottom of the sedimentation tank, and the third air distribution pipe is connected to the aeration fan.

[0014] In one embodiment of the present application, it also includes multiple air washing valves, multiple backwash water inlet valves and multiple backwash water outlet valves connected to the controller, multiple air washing valves are arranged in parallel on the branch pipeline at the outlet end of the aeration fan, multiple backwash water inlet valves are arranged in parallel on the branch pipeline at the outlet end of the backwash water pump, and multiple backwash water outlet valves are respectively arranged on the backwash outlet pipeline of each of the grid filter tanks.

[0015] In one embodiment of the present application, a sludge return pipeline is further included, wherein the sludge return pipeline connects the bottom of the sedimentation tank and the inlet end of the anaerobic tank;

[0016] It also includes a nitrification liquid reflux pipeline, which connects the outlet end of the aerobic tank and the inlet end of the anoxic tank.

[0017] In one embodiment of the present application, a suspended carrier is arranged in the aerobic pool, and nitrifying bacteria are attached to the suspended carrier.

[0018] In one embodiment of the present application, a regulating tank is also included, and the regulating tank is connected to the wastewater pipe and the inlet end of the water inlet pump.

[0019] In one embodiment of the present application, the regulating tank, water inlet pump, anaerobic tank, anoxic tank, aerobic tank, sedimentation tank, autotrophic denitrification filter, backwash water pump, aeration fan, magnetic sedimentation device and controller are integrated into an integrated arrangement.

[0020] Compared with the prior art, the utility model has the following beneficial effects:

[0021] 1. The sewage deep treatment system of the utility model integrates heterotrophic and autotrophic denitrification, and can realize deep denitrification treatment. The sulfur autotrophic carrier filler layer of the autotrophic denitrification filter tank also has a filtering function. No additional carbon source needs to be added during use, and COD, ammonia nitrogen, total nitrogen (TN), total phosphorus (TP) and suspended solids (SS) can be removed simultaneously, effectively ensuring the effluent quality; the autotrophic denitrification filter tank package is arranged into a plurality of grid filter tanks, which can be operated together or separately, and the blocked grid filter tank can be backwashed without interfering with each other, without stopping, so as to ensure the continuous and efficient operation of the system; a liquid level meter is arranged in the grid filter tank, and the liquid level meter is linked with the backwash water pump and the aeration fan through the controller, and the automatic backwashing operation can be realized through the liquid level change of each grid filter tank, which is convenient for use and maintenance; for example, when the sulfur autotrophic carrier filler layer of a grid filter tank is blocked, resulting in a high liquid level, the grid filter tank can be triggered to automatically backwash by monitoring the liquid level information through the liquid level meter.

[0022] 2. After setting up the autotrophic denitrification filter, deep denitrification can be achieved, but some phosphorus and SS may still remain in the wastewater. After the autotrophic denitrification filter treatment, a magnetic precipitation device is further set up. Combined with magnetic separation technology, deep removal of pollutants such as TP and SS in the wastewater can be achieved, achieving the effect of simultaneous deep removal of nitrogen, phosphorus and SS. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 The figure is a flow chart of a sewage deep treatment system.

[0025] Figure 2 This is a schematic diagram of the structure of the autotrophic denitrification filter.

[0026] Reference numerals:

[0027] 1. Anaerobic tank; 11. Water inlet pump; 12. Regulating tank;

[0028] 2. Anoxic pool;

[0029] 3. Aerobic pool; 31. Nitration liquid return pipeline; 32. Second gas distribution pipe;

[0030] 4. Sedimentation tank; 41. Sludge return pipeline; 42. Third air distribution pipe;

[0031] 5. Autotrophic denitrification filter tank; 50. Cell filter tank; 51. Support layer; 52. Sulfur autotrophic carrier filler layer; 53. Backwash water outlet; 54. Liquid level meter; 55. Water distributor; 56. First air distribution pipe;

[0032] 6. Backwash water pump;

[0033] 7. Aeration fan;

[0034] 8. Magnetic precipitation device. DETAILED DESCRIPTION

[0035] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0036] In the description of the present invention, it should be understood that the terms "middle", "upper", "lower", "front", "back", "top", "bottom", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships conventionally placed when the product of the present invention is used, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0037] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0038] The terms "install", "connect", "connect", "fix" and the like 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, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0039] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0040] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention.

[0041] The embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0042] The utility model provides a sewage deep treatment system. Figure 1 As shown, the system includes a controller (not shown in the figure), an anaerobic tank 1, an anoxic tank 2, an aerobic tank 3, a sedimentation tank 4, an autotrophic denitrification filter 5, a backwash water pump 6 and an aeration fan 7, wherein the anaerobic tank 1, the anoxic tank 2, the aerobic tank 3, the sedimentation tank 4 and the autotrophic denitrification filter 5 are connected in sequence via pipelines.

[0043] The anaerobic tank 1 is connected to the outlet end of the water inlet pump 11, and the water inlet pump 11 pumps the sewage to be treated into the anaerobic tank 1 and controls the water inlet flow rate.

[0044] like Figure 1 and Figure 2 As shown, the autotrophic denitrification filter 5 includes a plurality of grid filter tanks 50. A support layer 51 and a sulfur autotrophic carrier filler layer 52 are arranged in the middle of each grid filter tank 50; the water inlet and backwash outlet 53 of each grid filter tank 50 are arranged at the upper part, located above the sulfur autotrophic carrier filler layer 52; and the water outlet of each grid filter tank 50 is arranged at the lower part, located below the support layer 51.

[0045] The plurality of grid filter tanks 50 are arranged in parallel, that is, the water inlet of each grid filter tank 50 is connected to the water outlet of the sedimentation tank 4 respectively, and each grid filter tank 50 performs autotrophic denitrification, filtration and backwashing treatment independently.

[0046] It also includes a liquid level meter 54. Each grid filter 50 is provided with at least one such liquid level meter 54 for monitoring the liquid level change above the sulfur autotrophic carrier filler layer 52 in the grid filter 50. Each liquid level meter 54 is connected to the controller.

[0047] The supporting layer 51 in each grid filter tank 50 is connected to the outlet end of the backwash water pump 6 and the aeration fan 7 through a pipeline. The backwash water pump 6 and the aeration fan 7 pump in the backwash water and the backwash gas.

[0048] The backwash water pump 6 and the aeration fan 7 are both connected to the controller and associated with the liquid level meter 54 . The controller controls the operation of the backwash water pump 6 and the aeration fan 7 according to the liquid level information monitored by the liquid level meter 54 .

[0049] The sewage deep treatment system is provided with an autotrophic denitrification filter 5 to achieve deep denitrification and SS filtration; the autotrophic denitrification filter 5 is provided with a plurality of grid filter tanks 50 arranged in parallel, and the plurality of grid filter tanks 50 can be operated individually or simultaneously; when the operating liquid level is lower than 50% or less of the highest liquid level, the operation of some grid filter tanks 50 can be stopped, effectively reducing the energy consumption of equipment operation (the grid filter tank 50 that is stopped needs to be backwashed and emptied, effectively avoiding the empty bed operation of the grid filter tank 50 to produce hydrogen sulfide); when the grid filter tank 50 is blocked and the liquid level rises, some grid filter tanks 50 can be backwashed, and the remaining grid filter tanks 50 can be operated normally, ensuring continuous and stable operation of the system. The liquid level change is monitored by the liquid level meter 54 to trigger the operation of the backwash water pump 6 and the aeration fan 7, which can realize automatic backwash control, ensure the normal and efficient operation of the system, and the control is simple and reliable.

[0050] Furthermore, the sewage deep treatment system also includes a magnetic precipitation device 8, which is connected to the outlet of each grid filter 50, that is, the wastewater treated by each grid filter 50 enters the magnetic precipitation device 8 for further magnetic separation treatment. Although nitrogen is effectively removed from the wastewater treated by the autotrophic denitrification filter 5, some phosphorus and SS may still remain. The magnetic precipitation device 8 is provided to further remove phosphorus and SS. That is, the autotrophic denitrification is combined with the magnetic separation technology to achieve deep denitrification, phosphorus and SS, etc., and ensure the effluent quality.

[0051] In a preferred embodiment, a water distributor 55 and a first air distribution pipe 56 are provided at the bottom of each grid filter 50, and the water distributor 55 and the first air distribution pipe 56 are both located below the supporting layer 51. Each water distributor 55 is connected to the outlet end of the backwash water pump 6, and the backwash water flow is dispersed by the water distributor 55 into the grid filter 50 to flush and backwash the sulfur autotrophic carrier filler layer 52. Each first air distribution pipe 56 is connected to the outlet end of the aeration fan 7, and the first air distribution pipe 56 is provided to disperse and expose the gas into the grid filter 50, so as to better backwash the sulfur autotrophic carrier filler layer 52 by air washing or air-water combined backwashing.

[0052] Preferably, a second air distribution pipe 32 is provided at the bottom of the aerobic pool 3, and the second air distribution pipe 32 is also connected to the outlet end of the aeration fan 7 through a pipeline. The controller controls aeration into the aerobic pool 3, so that the microorganisms in the aerobic pool 3 can better perform aerobic nitrification reaction.

[0053] A third air distribution pipe 42 is arranged at the bottom of the sedimentation tank 4, and the third air distribution pipe 42 is also connected to the outlet end of the aeration fan 7 through a pipeline. The sedimentation tank 4 is backwashed and air-washed by the controller to ensure that the sedimentation tank 4 continues to operate efficiently.

[0054] That is, a plurality of branch pipes are arranged at the outlet end of the aeration fan 7, which are respectively connected to the first air distribution pipe 56 of each grid filter 50, the second air distribution pipe 32 of the aerobic tank 3 and the third air distribution pipe 42 of the sedimentation tank 4. The aeration fan 7 is shared by the aerobic tank 3, the sedimentation tank 4 and the autotrophic denitrification filter 5, and there is no conflict in their use, which effectively saves equipment investment.

[0055] Furthermore, the sewage deep treatment system also includes a plurality of air washing valves, a plurality of backwash water inlet valves and a plurality of backwash water outlet valves (not shown in the figure). The plurality of air washing valves are arranged in parallel on the branch pipeline at the outlet end of the aeration fan 7, and each air washing valve corresponds to a first air distribution pipe 56, a second air distribution pipe 32 or a third air distribution pipe 42, respectively controlling the air washing air intake of the grid filter 50, the aerobic tank 3 and the sedimentation tank 4. The plurality of backwash water inlet valves are arranged in parallel on the branch pipeline at the outlet end of the backwash water pump 6, that is, one backwash water inlet valve corresponds to a water distributor 55 in a grid filter 50, respectively controlling the backwash water intake of each grid filter 50. The plurality of backwash water outlet valves are respectively arranged on the backwash water outlet 53 pipeline of each grid filter 50, respectively controlling the backwash water flow in each grid filter 50 to be discharged from the upper part. The air wash valve, the backwash water inlet valve and the backwash water outlet valve are all connected to the controller and are opened or closed by the controller to realize automatic backwashing.

[0056] In addition, a water inlet switch valve is also provided at the water inlet on the upper part of each grid filter tank 50 , and the water inlet switch valve is also connected to the controller to control the water inlet of each grid filter tank 50 respectively.

[0057] like Figure 1As shown, the sewage deep treatment system is also provided with a sludge return pipeline 41 and a nitrification liquid return pipeline 31. The sludge return pipeline 41 connects the bottom of the sedimentation tank 4 and the inlet end of the anaerobic tank 1. A sludge pump is arranged on the sludge return pipeline 41. Part of the sludge deposited in the sedimentation tank 4 is returned to the anaerobic tank 1 through the sludge pump to replenish the required activated sludge for the anaerobic tank 1. The nitrification liquid return pipeline 31 connects the outlet end of the aerobic tank 3 and the inlet end of the anoxic tank 2. A reflux pump is arranged on the nitrification liquid return pipeline 31. Part of the nitrification liquid output from the aerobic tank 3 is returned to the inlet end of the anoxic tank 2 through the reflux pump, so that the refluxed nitrification liquid and the sewage discharged from the anaerobic tank 1 are merged and enter the anoxic tank 2, which is more conducive to the heterotrophic denitrification reaction in the anoxic tank 2.

[0058] A suspended carrier is arranged in the aerobic pool 3, on which nitrifying bacteria are attached. The wastewater treated in the anoxic pool 2 enters the aerobic pool 3 for further nitrification reaction to remove ammonia nitrogen under the action of nitrifying bacteria. The suspended carrier is attached with nitrifying bacteria, which can make the bacteria better contact and oxidize with pollutants.

[0059] It also includes a regulating tank 12, which is arranged at the front end and connected to the wastewater inlet pipe and the inlet end of the water inlet pump 11. The regulating tank 12 can mix and regulate the wastewater to be treated to ensure a continuous and stable supply of the wastewater to be treated, and provide a guarantee for the stable operation of the sewage deep treatment system.

[0060] Preferably, the regulating tank 12, the water inlet pump 11, the anaerobic tank 1, the anoxic tank 2, the aerobic tank 3, the sedimentation tank 4, the autotrophic denitrification filter 5, the backwash water pump 6, the aeration fan 7, the magnetic precipitation device 8 and the controller are integrated into an integrated device for easy installation and daily maintenance. Of course, only the anaerobic tank 1, the anoxic tank 2, the aerobic tank 3, the sedimentation tank 4, the autotrophic denitrification filter 5 and the magnetic precipitation device 8 can be integrated, and then the regulating tank 12, the water inlet pump 11, the backwash water pump 6, the aeration fan 7, the controller and other equipment can be selected according to the on-site needs, which is more flexible and convenient to use. Among them, the autotrophic denitrification filter 5 can be arranged according to the number of grid filters 50 as needed to better meet the operating conditions and adapt to different use occasions.

[0061] In summary, the sewage deep treatment system of the utility model integrates heterotrophic and autotrophic denitrification to achieve deep denitrification treatment; the sulfur autotrophic carrier filler layer 52 of the autotrophic denitrification filter 5 also has a filtering function, and no additional carbon source needs to be added during use, and COD, ammonia nitrogen, TN, TP and SS can be removed simultaneously, effectively ensuring the effluent quality; the autotrophic denitrification filter 5 is arranged into a plurality of grid filter tanks 50, which can be operated together or individually, and the blocked grid filter tank 50 can be backwashed without interfering with each other, without stopping, so as to ensure the continuous and efficient operation of the system; a liquid level meter 54 is arranged in the grid filter tank 50, and the liquid level meter 54 is linked with the backwash water pump 6 and the aeration fan 7 through a controller, and automatic backwashing control can be realized through the liquid level change of each grid filter tank 50, which is convenient for use and maintenance; for example, when the sulfur autotrophic carrier filler layer 52 of a grid filter tank is blocked, resulting in a high liquid level, the liquid level information monitored by the liquid level meter triggers the grid filter tank 50 to automatically backwash.

[0062] After the autotrophic denitrification filter 5 is set up, deep denitrification can be achieved, but some phosphorus and SS may still remain in the wastewater. After the autotrophic denitrification filter treatment, a magnetic precipitation device 8 is further set up. Combined with the magnetic separation technology, deep removal of pollutants such as TP and SS in the wastewater can be achieved, achieving the effect of simultaneous deep removal of nitrogen, phosphorus and SS.

Claims

1. A sewage deep treatment system, characterized in that: It includes an anaerobic tank (1), an anoxic tank (2), an aerobic tank (3), a sedimentation tank (4) and an autotrophic denitrification filter tank (5) which are connected in sequence; Wherein, the anaerobic tank (1) is connected to the outlet end of the water inlet pump (11); The autotrophic denitrification filter (5) comprises a plurality of grid filter tanks (50) arranged in parallel, each grid filter tank (50) being provided with a supporting layer (51) and a sulfur autotrophic carrier filler layer (52) in the middle thereof, the water inlet and the backwash water outlet (53) of the grid filter tank (50) being located above the sulfur autotrophic carrier filler layer (52), and the water outlet being located below the supporting layer (51); It also includes a controller and a liquid level meter (54), a backwash water pump (6), and an aeration fan (7) connected to the controller; each of the compartmented filter tanks (50) is provided with the liquid level meter (54); and the support layer (51) in each of the compartmented filter tanks (50) is connected to the outlet ends of the backwash water pump (6) and the aeration fan (7) below.

2. The sewage deep treatment system according to claim 1, characterized in that: It also comprises a magnetic precipitation device (8), wherein the magnetic precipitation device (8) is connected to the water outlet of each grid filter tank (50).

3. The sewage deep treatment system according to claim 1, characterized in that: A water distributor (55) is provided at the bottom of each of the compartmented filter tanks (50), and each of the water distributors (55) is connected to the backwash water pump (6).

4. The sewage deep treatment system according to claim 3, characterized in that: A first air distribution pipe (56) is provided at the bottom of each of the compartmented filter tanks (50), and each of the first air distribution pipes (56) is connected to the aeration fan (7).

5. The sewage deep treatment system according to claim 4, characterized in that: A second air distribution pipe (32) is provided at the bottom of the aerobic pool (3), and the second air distribution pipe (32) is connected to the aeration fan (7) via a pipeline; A third air distribution pipe (42) is provided at the bottom of the sedimentation tank (4), and the third air distribution pipe (42) is connected to the aeration fan (7).

6. The sewage deep treatment system according to any one of claims 1, 4 or 5, characterized in that: It also includes a plurality of air wash valves, a plurality of backwash water inlet valves and a plurality of backwash water outlet valves connected to the controller, wherein the plurality of air wash valves are arranged in parallel on the branch pipeline at the outlet end of the aeration fan (7), the plurality of backwash water inlet valves are arranged in parallel on the branch pipeline at the outlet end of the backwash water pump (6), and the plurality of backwash water outlet valves are respectively arranged on the backwash water outlet (53) pipeline of each of the compartmented filter tanks (50).

7. The sewage deep treatment system according to claim 1, characterized in that: It also includes a sludge return pipeline (41), wherein the sludge return pipeline (41) connects the bottom of the sedimentation tank (4) and the inlet end of the anaerobic tank (1); It also comprises a nitrification liquid return pipeline (31), wherein the nitrification liquid return pipeline (31) is connected to the outlet end of the aerobic tank (3) and the inlet end of the anoxic tank (2).

8. The sewage deep treatment system according to claim 1, characterized in that: A suspended carrier is arranged in the aerobic pool (3), and nitrifying bacteria are attached to the suspended carrier.

9. The sewage deep treatment system according to claim 2, characterized in that: It also comprises a regulating tank (12), wherein the regulating tank (12) is connected to the wastewater inlet pipe and the inlet end of the water inlet pump (11).

10. The sewage deep treatment system according to claim 9, characterized in that: The regulating tank (12), the water inlet pump (11), the anaerobic tank (1), the anoxic tank (2), the aerobic tank (3), the sedimentation tank (4), the autotrophic denitrification filter (5), the backwash pump (6), the aeration fan (7), the magnetic sedimentation device (8) and the controller are integrated into an integrated arrangement.

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