Wastewater treatment reconstruction system and reconstruction method based on aa0 / oxidation ditch process

Abstract

The application provides a sewage treatment reconstruction system and method based on an AA0 / oxidation ditch process. The sewage treatment reconstruction system comprises: a first pool body, which is physically separated into a first anoxic zone, an anaerobic zone and an aerobic zone, and the first anoxic zone, the anaerobic zone and the aerobic zone are arranged in sequence and are hydraulically connected; a second pool body, which is spaced from the first pool body, and the second pool body constitutes a second anoxic zone, and the second anoxic zone is hydraulically connected with the aerobic zone and the first anoxic zone respectively; and a separation and precipitation device, which is arranged in the aerobic zone and is used for realizing mud-water separation to obtain clarified water, so that the aerobic zone becomes an aerobic precipitation coupling zone. The sewage treatment reconstruction system provided by the application can solve the problem that system expansion is often difficult to implement under the condition that the site condition is limited.

Description

Technical Field

[0001] This application belongs to the field of wastewater treatment technology, specifically relating to a wastewater treatment retrofit system and method based on the AAO / oxidation ditch process. Background Technology

[0002] like Figure 1 As shown, a traditional AAO / oxidation ditch process system includes a first tank 10 and a second tank 20. The first tank 10 is divided into a target anaerobic zone 11', a target anoxic zone 12', and a target aerobic zone 13'. The second tank 20 is a secondary sedimentation tank 21'. The target anaerobic zone 11', the target anoxic zone 12', the target aerobic zone 13', and the secondary sedimentation tank 21' are connected sequentially.

[0003] The first tank is a physically separated but hydraulically connected whole. The activated sludge microbial community within the tank performs different purification tasks according to the environment created by each zone. The second tank (secondary sedimentation tank) is used to separate sludge from water to obtain clarified water.

[0004] Target anaerobic zone: Wastewater entering the system is mixed with returned activated sludge. Under anaerobic conditions, polyphosphate-accumulating bacteria release phosphorus and absorb organic matter from the stored wastewater.

[0005] Target anoxic zone: Nitrate nitrogen from the target aerobic zone reacts with organic matter in the wastewater, and denitrifying bacteria in the activated sludge convert it into nitrogen gas for removal.

[0006] The target aerobic zone: thoroughly oxidizes the remaining organic matter in the wastewater and converts ammonia nitrogen into nitrate nitrogen, while polyphosphate-accumulating bacteria absorb excessive amounts of phosphorus from the water.

[0007] Secondary sedimentation tank: After the mixed liquor enters the secondary sedimentation tank, the activated sludge settles and separates. The upper layer is the treated clarified water, which is discharged as qualified effluent. Most of the settled sludge is returned to the target anaerobic zone for recycling, and a small portion is discharged as phosphorus-rich excess sludge, thus achieving the final removal of phosphorus.

[0008] When it is necessary to increase the wastewater treatment capacity of an existing wastewater treatment system, this can usually be achieved by expanding the tank. However, for the aforementioned AAO / oxidation ditch + secondary sedimentation tank process system, system expansion is often difficult to implement when site conditions are limited. Summary of the Invention

[0009] This application provides a wastewater treatment retrofit system and method based on the AAO / oxidation ditch process, including but not limited to solving the problem that system expansion is often difficult to implement under limited site conditions.

[0010] The technical solution adopted in the embodiments of this application is: In a first aspect, this application provides a wastewater treatment retrofit system based on the AAO / oxidation ditch process, the wastewater treatment retrofit system comprising: The first pool body is physically divided into a first anoxic zone, an anaerobic zone, and an aerobic zone, which are arranged sequentially and hydraulically connected. A second pool, spaced apart from the first pool, constitutes a second anoxic zone, which is hydraulically connected to both the aerobic zone and the first anoxic zone; and A separation and sedimentation device is provided in the aerobic zone. The separation and sedimentation device is used to separate mud and water to obtain clarified water, so that the aerobic zone becomes an aerobic sedimentation coupling zone.

[0011] In one embodiment, the aerobic zone includes a first aerobic zone and a second aerobic zone, the first aerobic zone being hydraulically connected to the anaerobic zone, the second aerobic zone being hydraulically connected to the second anoxic zone, and the separation and sedimentation device being located in the second aerobic zone.

[0012] In one embodiment, the wastewater treatment retrofit system further includes an aeration pipe located at the bottom of the aerobic zone.

[0013] In one embodiment, the wastewater treatment modification system further includes a stirrer, and at least one of the first anoxic zone, the anaerobic zone, and the second anoxic zone is equipped with the stirrer.

[0014] In one embodiment, the wastewater treatment renovation system further includes a first pipe, through which the aerobic zone and the second anoxic zone are connected, and the first pipe is connected to the top of the second anoxic zone.

[0015] In one embodiment, the wastewater treatment renovation system further includes a second pipe, through which the second anoxic zone and the first anoxic zone are connected. One end of the second pipe is connected to the bottom of the second anoxic zone, and the other end of the second pipe is located at the top of the first anoxic zone.

[0016] In one embodiment, the separation and sedimentation device includes a frame assembly, a separation assembly, and an outlet weir. The frame assembly has a receiving space, and both the separation assembly and the outlet weir are disposed within the receiving space. The outlet weir is located at the top of the receiving space, and the separation assembly is located below the outlet weir. The separation assembly is used to separate mud and water to form clarified water above the separation assembly, and the outlet weir is used to collect the clarified water.

[0017] In one embodiment, the separation component includes a gas collecting pipe, a plurality of upper gas collecting hoods, and a plurality of lower gas collecting hoods arranged sequentially from top to bottom. The plurality of upper gas collecting hoods and the plurality of lower gas collecting hoods are arranged laterally at intervals, and the upper gas collecting hoods and the lower gas collecting hoods are arranged in a one-to-one correspondence. The gas collecting pipe, the upper gas collecting hoods, and the lower gas collecting hoods are connected sequentially.

[0018] In one embodiment, the aerobic zone is provided with a reflux port, and the aerobic zone is connected to the second anoxic zone through the reflux port. The outlet of the gas collecting pipe is located below the reflux port.

[0019] Secondly, this application also provides a modification method based on the AAO / oxidation ditch process. The AAO / oxidation ditch process system includes a first tank and a second tank. The first tank is divided into a target anaerobic zone, a target anoxic zone, and a target aerobic zone. The second tank is a secondary sedimentation tank. The modification method includes: The target anaerobic zone of the AAO / oxidation ditch process system is transformed into the first anoxic zone; The target anoxic zone of the AAO / oxidation ditch process system is transformed into an anaerobic zone; The target aerobic zone of the AAO / oxidation ditch process system is modified into an aerobic zone equipped with a separation and sedimentation device. The separation and sedimentation device is used to separate mud and water to obtain clarified water, so that the aerobic zone becomes an aerobic sedimentation coupling zone. The secondary sedimentation tank of the AAO / oxidation ditch process system was modified into a second anoxic zone.

[0020] The wastewater treatment retrofit system provided in this application is based on the traditional AAO / oxidation ditch process system. Specifically, based on the original first and second tanks of the AAO / oxidation ditch process, the target anaerobic zone is transformed into a first anoxic zone, and a separation and sedimentation device is installed in the target aerobic zone to transform the target aerobic zone into an aerobic sedimentation coupling zone. The secondary sedimentation tank is transformed into a second anoxic zone, thus obtaining the wastewater treatment retrofit system of this application. For the modified wastewater treatment system, its aerobic sedimentation coupling zone not only enables aerobic reactions between activated sludge and wastewater but also achieves sludge-water separation using a separation sedimentation device. This is equivalent to combining the original secondary sedimentation tank with the target aerobic zone, while simultaneously transforming the original secondary sedimentation tank into a second anoxic zone. This results in the total volume of the anoxic zone in the modified wastewater treatment system (the sum of the volumes of the first and second anoxic zones) being greater than the original target anoxic zone's volume. Consequently, the total volume of the modified biochemical reaction zone is greater than that before the modification, leading to an increase in the total volume of the biochemical reaction zone and a corresponding increase in wastewater treatment capacity. Therefore, the wastewater treatment modification system provided in this application can solve the problem of system expansion being difficult to implement under limited site conditions. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a traditional AAO / oxidation ditch process system.

[0023] Figure 2 A perspective view of the wastewater treatment retrofit system provided in the embodiments of this application.

[0024] Figure 3 A schematic diagram of a wastewater treatment retrofit system provided in an embodiment of this application.

[0025] Figure 4 for Figure 2 The diagram shows the frame assembly of the separation and sedimentation device in the wastewater treatment renovation system.

[0026] Figure 5 A schematic diagram of a separation and precipitation device set up in an aerobic zone, provided in an embodiment of this application.

[0027] Figure 6 A simplified schematic diagram illustrating the working principle of the separation and precipitation device provided in the embodiments of this application.

[0028] Figure 7 This is a schematic diagram of the separation component in the separation and precipitation apparatus provided in the embodiments of this application.

[0029] Explanation of key figure labels: First tank 10, target anaerobic zone 11', target anoxic zone 12', target aerobic zone 13', second tank 20, secondary sedimentation tank 21'; First tank 10, first anoxic zone 11, anaerobic zone 12, aerobic zone 13, first aerobic zone 131, second aerobic zone 132, return port 133, second tank 20, second anoxic zone 21, separation sedimentation device 30, frame assembly 31, containment space 311, partition 312, separation assembly 32, air collection pipe 321, air outlet 3211, upper air collection hood 322, second inlet 3221, second outlet 3222, third inclined plate 3223, fourth inclined plate 3224, lower air collection hood 323, first inlet 3231, first outlet 3232, first inclined plate 3233, second inclined plate 3234, effluent weir 33, first flow channel X1, second flow channel X2, third flow channel X3, aeration pipe 40, stirrer 50, first pipe 60, second pipe 70, first inlet end 80, second inlet end 90. Detailed Implementation

[0030] The technical solutions of the embodiments 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, and 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.

[0031] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0032] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0033] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; 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, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0034] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0035] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.

[0036] Please refer to Figure 2 and Figure 3 This application provides a wastewater treatment modification system based on the AAO / oxidation ditch process. The wastewater treatment modification system includes: a first tank 10, a second tank 20, and a separation and sedimentation device 30. The first tank 10 is physically divided into a first anoxic zone 11, an anaerobic zone 12, and an aerobic zone 13, which are arranged sequentially and hydraulically connected. The second tank 20 is spaced apart from the first tank 10 and constitutes a second anoxic zone 21, which is hydraulically connected to both the aerobic zone 13 and the first anoxic zone 11. The separation and sedimentation device 30 is located in the aerobic zone 13 and is used to separate sludge from water to obtain clarified water, so that the aerobic zone 13 becomes an aerobic sedimentation coupling zone.

[0037] Among them, the first anoxic zone 11 and the second anoxic zone 21 are used for denitrification. That is, under anoxic conditions, denitrifying bacteria in activated sludge use organic matter in wastewater to reduce nitrate nitrogen to harmless nitrogen gas, which then escapes from the water into the atmosphere, thereby achieving denitrification.

[0038] Among them, the anaerobic zone 12 is used to release phosphorus and store phosphorus uptake energy. That is, under anaerobic conditions, polyphosphate-accumulating bacteria in the activated sludge release phosphorus into the wastewater, while absorbing and storing easily degradable organic matter in the wastewater, in preparation for subsequent excessive phosphorus uptake in the aerobic zone 13.

[0039] The aerobic zone 13 is used to oxidize organic matter, nitrify ammonia nitrogen, and absorb excess phosphorus. Under aeration and oxygenation conditions, the aerobic bacteria in the activated sludge completely oxidize and decompose the remaining organic matter in the wastewater; the nitrifying bacteria in the activated sludge convert ammonia nitrogen in the wastewater into nitrate nitrogen; at the same time, the polyphosphate-accumulating bacteria in the activated sludge use the energy stored in the anaerobic zone 12 to absorb excess phosphorus from the wastewater into their bodies, thereby achieving efficient removal of pollutants.

[0040] In practical applications, the second anoxic zone 21 can serve as the starting point of the process. The mixture of wastewater and activated sludge flows from the second anoxic zone 21 to the first anoxic zone 11, then from the first anoxic zone 11 to the anaerobic zone 12, and finally from the anaerobic zone 12 to the aerobic zone 13. The aerobic zone 13 has two liquid flow directions: first, a portion of the mixture flows back to the second anoxic zone 21; second, a portion of the mixture enters the separation and sedimentation device 30. The activated sludge settles in the lower part of the separation and sedimentation device 30, resulting in clarified water (sludge-water separation) at the top of the device. This clarified water is then collected and discharged from the system. Therefore, the aerobic zone 13, equipped with the separation and sedimentation device 30, not only enables aerobic reactions between activated sludge and wastewater but also achieves sludge-water separation using the separation and sedimentation device 30. This makes the aerobic zone 13 essentially an aerobic sedimentation coupling zone. It should be noted that the number of separation and sedimentation devices 30 set in the aerobic zone 13 can be one or more. For example, the number of separation and sedimentation devices 30 can be 1, 2, 3, 4, 5, etc. This application only uses 3 as an example.

[0041] The wastewater treatment modification system provided in this application is based on the modification of the traditional AAO / oxidation ditch process system. Specifically, based on the original first tank 10 and second tank 20 of the AAO / oxidation ditch process, the target anaerobic zone 11' is modified into the first anoxic zone 11, and the target anoxic zone 12' is modified into the anaerobic zone 12. A separation sedimentation device 30 is installed in the target aerobic zone 13' to modify the target aerobic zone 13' into an aerobic sedimentation coupling zone, and the secondary sedimentation tank 21' is modified into the second anoxic zone 21. Thus, the wastewater treatment modification system of this application is obtained. For the modified wastewater treatment system, its aerobic sedimentation coupling zone not only enables aerobic reactions between activated sludge and wastewater, but also achieves sludge-water separation using the separation sedimentation device 30. This is equivalent to combining the original secondary sedimentation tank 21' with the target aerobic zone 13', while simultaneously transforming the original secondary sedimentation tank 21' into a second anoxic zone 21. This results in the total volume of the anoxic zone in the modified wastewater treatment system (the sum of the volumes of the first anoxic zone 11 and the second anoxic zone 21) being greater than the volume of the original target anoxic zone 12'. Consequently, the total volume of the modified biochemical reaction zone is greater than that before the modification, leading to an increase in the total volume of the biochemical reaction zone and a corresponding increase in wastewater treatment capacity. Therefore, the wastewater treatment modification system provided in this application can solve the problem that system expansion is often difficult to implement under limited site conditions.

[0042] Please refer to Figure 2 and Figure 3In one embodiment, the aerobic zone 13 includes a first aerobic zone 131 and a second aerobic zone 132. The first aerobic zone 131 is hydraulically connected to the anaerobic zone 12, and the second aerobic zone 132 is hydraulically connected to the second anoxic zone 21. The separation and sedimentation device 30 is located in the second aerobic zone 132.

[0043] The first aerobic zone 131 and the second aerobic zone 132 are not physically separated; they are simply different areas within the aerobic zone 13. In one embodiment, the volume of the first aerobic zone 131 is exactly the same as the volume of the second aerobic zone 132; in another embodiment, the volume of the first aerobic zone 131 is larger than the volume of the second aerobic zone 132; and in yet another embodiment, the volume of the first aerobic zone 131 is smaller than the volume of the second aerobic zone 132. Placing the separation and sedimentation device 30 in the second aerobic zone 132 ensures that wastewater and activated sludge first fully contact and react in the first aerobic zone 131 before entering the separation and sedimentation device 30 to obtain clarified water, thus guaranteeing better water quality.

[0044] Please refer to Figure 3 In one embodiment, the wastewater treatment modification system further includes an aeration pipe 40, which is located at the bottom of the aerobic zone 13 and is simultaneously located in the first aerobic zone 131 and the second aerobic zone 132. The aeration pipe 40 may include a main pipe and multiple branch pipes, which are spaced apart along the length of the main pipe and connected to it. The main pipe is used to connect to an air supply source (such as a blower). When the air supply source is operating, external gas (such as air or pure oxygen) is first input into the main pipe and then released from the branch pipes into the aerobic zone 13 to provide oxygen to the aerobic microorganisms. When the aeration pipe 40 aerates, a large number of bubbles are generated. These bubbles disturb the water flow as they rise, allowing the wastewater, activated sludge, and oxygen to mix thoroughly, thereby ensuring sufficient contact and reaction between the activated sludge and the wastewater.

[0045] Please refer to Figure 3 In one embodiment, the wastewater treatment modification system further includes a stirrer 50, and at least one of the first anoxic zone 11, the anaerobic zone 12, and the second anoxic zone 21 is equipped with the stirrer 50.

[0046] In one embodiment, any one of the first anoxic zone 11, the anaerobic zone 12, and the second anoxic zone 21 is equipped with a stirrer 50.

[0047] In another embodiment, any two of the first anoxic zone 11, the anaerobic zone 12, and the second anoxic zone 21 are equipped with a stirrer 50.

[0048] In another embodiment, a stirrer 50 is provided in all three of the anoxic zones: the first anoxic zone 11, the anaerobic zone 12, and the second anoxic zone 21.

[0049] The agitator 50 is used to stir the mixture so that the activated sludge and wastewater can fully contact and react, avoiding excessive settling of activated sludge to the bottom, thereby ensuring that the wastewater treatment capacity is at an ideal level.

[0050] Please refer to Figure 3 In one embodiment, the wastewater treatment modification system further includes a first pipe 60, through which the aerobic zone 13 and the second anoxic zone 21 are connected, and the first pipe 60 is connected to the top of the second anoxic zone 21. It is understood that, due to the natural settling of activated sludge under gravity, if the mixed liquor from the aerobic zone 13 enters the second anoxic zone 21 from the bottom, most of the activated sludge will accumulate at the bottom of the second anoxic zone 21, resulting in insufficient contact and reaction between the wastewater and the activated sludge. In this embodiment, the first pipe 60 is connected to the top of the second anoxic zone 21. This arrangement ensures that when the mixed liquor from the aerobic zone 13 enters the second anoxic zone 21, the mixed liquor enters from the top of the second anoxic zone 21, allowing for more thorough contact and reaction between the wastewater and activated sludge in the second anoxic zone 21.

[0051] Please refer to Figure 3 In one embodiment, the wastewater treatment modification system further includes a second pipe 70, through which the second anoxic zone 21 and the first anoxic zone 11 are connected. One end of the second pipe 70 is connected to the bottom of the second anoxic zone 21, and the other end is located at the top of the first anoxic zone 11. Since activated sludge will naturally settle under gravity, connecting one end of the second pipe 70 to the bottom of the second anoxic zone 21 allows for more efficient transport of the activated sludge settled at the bottom of the second anoxic zone 21 to the first anoxic zone 11. Simultaneously, placing the other end of the second pipe 70 at the top of the first anoxic zone 11 allows the mixed liquor from the second anoxic zone 21 to enter the first anoxic zone 11 from the top, thus enabling more thorough contact and reaction between the wastewater and activated sludge in the first anoxic zone 11.

[0052] Please refer to Figure 3 In one embodiment, the wastewater treatment modification system is provided with a first inlet 80, which is located corresponding to the anaerobic zone 12, to supply wastewater to the anaerobic zone 12. And / or, the wastewater treatment modification system is provided with a second inlet 90, which is located corresponding to the second anoxic zone 21, to supply wastewater to the second anoxic zone 21.

[0053] In one embodiment, only a first inlet 80 is provided to supply wastewater to the anaerobic zone 12.

[0054] In another embodiment, only a second inlet 90 is provided to supply wastewater to the second anoxic zone 21.

[0055] In another embodiment, a first inlet 80 for supplying wastewater to the anaerobic zone 12 and a second inlet 90 for supplying wastewater to the second anoxic zone 21 are provided simultaneously.

[0056] Please refer to Figure 4 and Figure 5 In one embodiment, the separation and sedimentation device 30 includes a frame assembly 31, a separation assembly 32, and an outlet weir 33. The frame assembly 31 has a receiving space 311. The separation assembly 32 and the outlet weir 33 are both disposed within the receiving space 311, with the outlet weir 33 located at the top of the receiving space 311 and the separation assembly 32 located below the outlet weir 33. The separation assembly 32 is used to achieve mud-water separation to form clarified water above the separation assembly 32, and the outlet weir 33 is used to collect the clarified water.

[0057] The frame assembly 31 can be composed of multiple partitions 312. The material of the partitions 312 can be, but is not limited to, stainless steel, fiberglass, polyethylene, etc. Multiple partitions 312 are connected end-to-end to enclose the receiving space 311. The projection shape of the receiving space 311 on the ground can be, but is not limited to, circular, angular, elliptical, etc. The receiving space 311 is divided into a first region and a second region from bottom to top. The separation assembly 32 is located in the first region, and the effluent weir 33 is located at the top of the second region. The first region is connected to the aerobic zone 13, meaning that the mixed liquor in the aerobic zone 13 can enter the first region. When the mixed liquor enters the first region from the aerobic zone 13, the separation assembly 32 functions, causing the activated sludge to settle downwards, achieving sludge-water separation, resulting in clarified water in the second region. This clarified water is collected by the effluent weir 33 and then discharged from the system.

[0058] The top of the frame assembly 31 can be flush with or exceed the top of the aerobic zone 13 tank. This arrangement is to prevent mixed liquid outside the separation and sedimentation device 30 from flowing into the clarified water from the top of the frame assembly 31.

[0059] Please refer to Figure 5 and Figure 6In one embodiment, the separation component 32 includes a gas collecting pipe 321, a plurality of upper gas collecting hoods 322, and a plurality of lower gas collecting hoods 323 arranged sequentially from top to bottom. The gas collecting pipe 321, the upper gas collecting hoods 322, and the lower gas collecting hoods 323 are connected in sequence. The plurality of upper gas collecting hoods 322 and the plurality of lower gas collecting hoods 323 are arranged laterally at intervals, and the upper gas collecting hoods 322 and the lower gas collecting hoods 323 are arranged in a one-to-one correspondence. That is, there is one upper gas collecting hood 322 above one lower gas collecting hood 323, and the upper gas collecting hoods 322 and the lower gas collecting hoods 323 are directly opposite each other.

[0060] A first flow channel X1 is formed by a gap between adjacent upper gas collecting hoods 322 and lower gas collecting hoods 323. A second flow channel X2 is formed by a gap between two adjacent lower gas collecting hoods 323. A third flow channel X3 is formed by a gap between two adjacent upper gas collecting hoods 322.

[0061] In practical applications, the bubbles generated by aeration at the bottom of the aerobic zone 13 via aeration pipe 40 will gradually rise. Due to the surface tension and viscosity of water, the bubbles will carry the mixed liquid upwards as they rise. The bubbles below the separation and sedimentation device 30 will first carry the mixed liquid into the lower gas collection hood 323, and then into the upper gas collection hood 322. The bubbles and mixed liquid entering the upper gas collection hood 322 will then diverge into two paths. The bubbles will continue to rise until they reach the gas collection pipe 321, where the gas will be collected, while the mixed liquid will flow out from the first flow channel X1. The mixed liquid flowing out from the first flow channel X1 will be divided into two paths again. As the bubbles rise, they carry some of the mixed liquid away from the aerobic zone 13 and move upward. Therefore, some of the mixed liquid will flow from the first flow channel X1 to the second flow channel X2 and move downward to the aerobic zone 13 (the first flow path) to supplement the aerobic zone 13 below the separation and sedimentation device 30. At the same time, as the effluent weir 33 continuously discharges the clarified water from the top of the separation and sedimentation device 30, some of the mixed liquid will flow from the first flow channel X1 to the third flow channel X3 and move upward to the effluent weir 33 (the second flow path). In the second flow path, as the mixed liquor moves upward, the activated sludge within it settles under its own weight, forming clarified water above the separation component 32. The settled activated sludge then falls and accumulates between two adjacent lower gas collection hoods 323 or on top of the lower gas collection hoods 323. Therefore, the mixed liquor flowing through the first flow path carries away this settled and accumulated activated sludge, returning it to the aerobic zone 13 below the separation and sedimentation device 30. Furthermore, the settling and accumulation of this activated sludge reduces its concentration ratio, making it easier for the activated sludge to settle, thus facilitating sludge-water separation. It is understood that after returning to the aerobic zone 13, the mixed liquor flowing through the first flow path will re-enter the separation and sedimentation device 30 with the air bubbles, thus creating a hydraulic cycle inside and outside the lower gas collection hood 323.

[0062] Please refer to Figure 7 The lower gas collecting hood 323 has a first inlet 3231 and a first outlet 3232, while the upper gas collecting hood 322 has a second inlet 3221 and a second outlet 3222. The first inlet 3231, first outlet 3232, second inlet 3221, and second outlet 3222 are sequentially connected from bottom to top, and the second outlet 3222 is connected to the gas collecting pipe 321. During its ascent, the bubbles will sequentially enter the gas collecting pipe 321 through the first inlet 3231, first outlet 3232, second inlet 3221, and second outlet 3222 to be collected. The size of the first inlet 3231 is larger than the size of the first outlet 3232, and the size of the second inlet 3221 is larger than the size of the second outlet 3222. In other words, both the lower gas collecting hood 323 and the upper gas collecting hood 322 have a structure that gradually narrows from bottom to top, which facilitates the gradual collection of gas into the gas collecting pipe 321. It should be noted that the lower gas collection hood 323 and the upper gas collection hood 322 only need to meet the above-mentioned closing requirements. The specific shape can be set as trapezoidal, conical, etc., and there is no limitation here.

[0063] Please refer to Figure 7 The lower gas collection hood 323 includes a first inclined plate 3233 and a second inclined plate 3234. Both the first inclined plate 3233 and the second inclined plate 3234 are inclined to form a first inlet 3231 and a first outlet 3232. It can be understood that the inclined arrangement of the first inclined plate 3233 and the second inclined plate 3234 facilitates the sliding of activated sludge settling on the top of the first inclined plate 3233 and the second inclined plate 3234 between the two adjacent lower gas collection hoods 323, thereby making it easier for the mixed liquor flowing through the first flow path to carry away these settled and accumulated activated sludge.

[0064] Please refer to Figure 7 The upper gas collection hood 322 includes a third inclined plate 3223 and a fourth inclined plate 3224. Both the third inclined plate 3223 and the fourth inclined plate 3224 are inclined to form a second inlet 3221 and a second outlet 3222. It can be understood that the inclined arrangement of the third inclined plate 3223 and the fourth inclined plate 3224 facilitates the sliding of activated sludge settled on the top of the third inclined plate 3223 and the fourth inclined plate 3224 to the top of the lower gas collection hood 323, and then from the top of the lower gas collection hood 323 to between two adjacent lower gas collection hoods 323, thereby facilitating the removal of these settled and accumulated activated sludge by the mixed liquid flowing through the first flow path.

[0065] Please refer to Figure 6In one embodiment, the aerobic zone 13 is provided with a return port 133, and the aerobic zone 13 is connected to the second hypoxic zone 21 through the return port 133, that is, the return port 133 is connected to the first pipe 60, the gas collecting pipe 321 extends out of the frame assembly 31 and the gas outlet 3211 of the gas collecting pipe 321 is located below the return port 133.

[0066] In practical applications, the gas collected by the gas collecting pipe 321 is discharged from the gas outlet 3211. After being discharged, the gas forms bubbles that rise. Due to the surface tension and viscosity of water, the bubbles carry the mixed liquid upwards. Simultaneously, since the gas outlet 3211 of the gas collecting pipe 321 is located below the return port 133, the rising bubbles can promote the flow of the mixed liquid from the aerobic zone 13 into the second anoxic zone 21. Thus, no additional power source is needed to drive the mixed liquid from the aerobic zone 13 to the second anoxic zone 21, or the driving force of the power source can be reduced, thereby achieving energy savings. The number of gas outlets 3211 can be one or more, for example, 1, 2, 3, 4, 5, or 6.

[0067] Optionally, the gas collecting pipes 321 in each of the separation and sedimentation devices 30 are connected. This arrangement allows the gas collecting pipes 321 to collect more gas, which makes it easier to determine the direction of the mixed liquid to the return port 133.

[0068] This application also provides a modification method based on the AAO / oxidation ditch process. Please refer to... Figure 1 The AAO / oxidation ditch process system includes a first tank 10 and a second tank 20. The first tank 10 is divided into a target anaerobic zone 11', a target anoxic zone 12', and a target aerobic zone 13'. The second tank 20 is a secondary sedimentation tank 21'.

[0069] The modification method includes steps S100, S200, S300, and S400. The details of steps S100, S200, S300, and S400 are as follows.

[0070] S100: The target anaerobic zone 11' of the AAO / oxidation ditch process system is transformed into the first anoxic zone 11.

[0071] S200: The target anoxic zone 12' of the AAO / oxidation ditch process system is transformed into an anaerobic zone 12.

[0072] S300: The target aerobic zone 13' of the AAO / oxidation ditch process system is transformed into an aerobic zone 13 equipped with a separation and sedimentation device 30. The separation and sedimentation device 30 is used to achieve mud-water separation to obtain clarified water, so that the aerobic zone 13 becomes an aerobic sedimentation coupling zone.

[0073] S400: The secondary sedimentation tank 21' of the AAO / oxidation ditch process system is transformed into the second anoxic zone 21.

[0074] For the modified first anoxic zone 11, anaerobic zone 12, aerobic zone 13 (aerobic precipitation coupling zone), second anoxic zone 21, separation and precipitation device 30, etc., please refer to the description and corresponding drawings in the previous structural embodiments, and will not be repeated here. It should be noted that there is no limitation on the order of the above steps S100, S200, S300, and S400. Each step can be performed simultaneously or sequentially. For example, the order of the modification method can be S100, S200, S300, S400, or it can be S300, S200, S100, S400, etc.

[0075] The technical means disclosed in this application are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

Claims

1. A wastewater treatment retrofit system based on the AAO / oxidation ditch process, characterized in that, The wastewater treatment retrofit system includes: The first pool (10) is physically divided into a first anoxic zone (11), an anaerobic zone (12), and an aerobic zone (13). The first anoxic zone (11), the anaerobic zone (12), and the aerobic zone (13) are arranged in sequence and hydraulically connected. A second pool (20) is spaced apart from the first pool (10), and the second pool (20) constitutes a second anoxic zone (21). The second anoxic zone (21) is hydraulically connected to the aerobic zone (13) and the first anoxic zone (11). Separation and sedimentation device (30) is provided in the aerobic zone (13). The separation and sedimentation device (30) is used to achieve mud-water separation to obtain clarified water, so that the aerobic zone (13) becomes an aerobic sedimentation coupling zone.

2. The wastewater treatment retrofit system as described in claim 1, characterized in that, The aerobic zone (13) includes a first aerobic zone (131) and a second aerobic zone (132). The first aerobic zone (131) is hydraulically connected to the anaerobic zone (12), and the second aerobic zone (132) is hydraulically connected to the second anoxic zone (21). The separation and sedimentation device (30) is located in the second aerobic zone (132).

3. The wastewater treatment retrofit system as described in claim 1, characterized in that, The wastewater treatment renovation system also includes an aeration pipe (40), which is located at the bottom of the aerobic zone (13).

4. The wastewater treatment retrofit system as described in claim 1, characterized in that, The wastewater treatment renovation system also includes a stirrer (50), and at least one of the first anoxic zone (11), the anaerobic zone (12), and the second anoxic zone (21) is equipped with the stirrer (50).

5. The wastewater treatment retrofit system as described in claim 1, characterized in that, The wastewater treatment renovation system also includes a first pipe (60), through which the aerobic zone (13) and the second anoxic zone (21) are connected, and the first pipe (60) is connected to the top of the second anoxic zone (21).

6. The wastewater treatment retrofit system as described in claim 1, characterized in that, The wastewater treatment renovation system also includes a second pipe (70), through which the second anoxic zone (21) and the first anoxic zone (11) are connected. One end of the second pipe (70) is connected to the bottom of the second anoxic zone (21), and the other end of the second pipe (70) is located at the top of the first anoxic zone (11).

7. The wastewater treatment renovation system as described in any one of claims 1 to 6, characterized in that, The separation and sedimentation device (30) includes a frame assembly (31), a separation assembly (32), and an outlet weir (33). The frame assembly (31) has a receiving space (311). The separation assembly (32) and the outlet weir (33) are both located in the receiving space (311), and the outlet weir (33) is located at the top of the receiving space (311). The separation assembly (32) is located below the outlet weir (33). The separation assembly (32) is used to achieve mud-water separation to form clear water above the separation assembly (32). The outlet weir (33) is used to collect the clear water.

8. The wastewater treatment retrofit system as described in claim 7, characterized in that, The separation component (32) includes a gas collecting pipe (321), multiple upper gas collecting hoods (322), and multiple lower gas collecting hoods (323) arranged sequentially from top to bottom. The multiple upper gas collecting hoods (322) and the multiple lower gas collecting hoods (323) are arranged horizontally at intervals, and the upper gas collecting hoods (322) and the lower gas collecting hoods (323) are arranged in a one-to-one correspondence. The gas collecting pipe (321), the upper gas collecting hoods (322), and the lower gas collecting hoods (323) are connected sequentially.

9. The wastewater treatment retrofit system as described in claim 8, characterized in that, The aerobic zone (13) is provided with a return port (133), and the aerobic zone (13) is connected to the second hypoxic zone (21) through the return port (133). The outlet (3211) of the gas collecting pipe (321) is located below the return port (133).

10. A modification method based on the AAO / oxidation ditch process, characterized in that, The AAO / oxidation ditch process system includes a first tank (10) and a second tank (20). The first tank (10) is divided into a target anaerobic zone (11'), a target anoxic zone (12'), and a target aerobic zone (13'). The second tank (20) is a secondary sedimentation tank (21'). The modification method includes: The target anaerobic zone (11') of the AAO / oxidation ditch process system is transformed into the first anoxic zone (11). The target anoxic zone (12') of the AAO / oxidation ditch process system is transformed into an anaerobic zone (12). The target aerobic zone (13') of the AAO / oxidation ditch process system is transformed into an aerobic zone (13) equipped with a separation and sedimentation device (30). The separation and sedimentation device (30) is used to achieve mud-water separation to obtain clarified water, so that the aerobic zone (13) becomes an aerobic sedimentation coupling zone. The secondary sedimentation tank (21') of the AAO / oxidation ditch process system is transformed into a second anoxic zone (21).

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