A sewage treatment reconstruction system and method based on SBR or CASS process

Abstract

This application provides a wastewater treatment retrofit system and method based on SBR or CASS processes. The wastewater treatment retrofit system includes: a reaction tank, comprising a tank body, a first partition wall, and a second partition wall, both located within the tank body and spaced apart, physically dividing the tank body into sequentially hydraulically connected anoxic, anaerobic, and aerobic zones, wherein the aerobic zone is connected to the anoxic zone; and a separation and sedimentation device located within the aerobic zone, used to achieve sludge-water separation to obtain clarified water, thus making the aerobic zone an aerobic sedimentation coupling zone. Compared to SBR or CASS processes, the retrofitted wastewater treatment system, by dividing the system into multiple reaction zones, each performing different functions, avoids the problems of SBR or CASS processes requiring precise switching at each stage within the cycle and highly relying on automation. In other words, the retrofitted wastewater treatment system has lower automation dependence, simpler control, and improves tank volume utilization.

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 SBR or CASS processes. Background Technology

[0002] In wastewater treatment processes, both SBR (Sequencing Batch Reactor) and CASS (Circulating Activated Sludge Process) are intermittent activated sludge processes. Both employ a cyclical "influent-reaction-sedimentation-effluent-idle" operation mode, with all processes separated by time rather than space. Both also utilize a single tank, where biological reactions, sludge-water separation, and effluent are completed sequentially. However, SBR or CASS processes require precise switching between each stage (influent, aeration, sedimentation, effluent) within their cycle, resulting in high automation dependence, complex control, and low tank capacity utilization. Summary of the Invention

[0003] This application provides a wastewater treatment retrofit system and method based on SBR or CASS processes, including but not limited to solving the problems of precise switching between different stages of the SBR or CASS process cycle, high degree of automation dependence, complex control, and low tank volume utilization.

[0004] The technical solution adopted in the embodiments of this application is: Firstly, this application provides a wastewater treatment retrofit system based on SBR or CASS processes, the wastewater treatment retrofit system comprising: A reaction tank, comprising a tank body, a first partition wall, and a second partition wall, wherein the first and second partition walls are both disposed within the tank body and are spaced apart from each other to physically divide the tank body into an anoxic zone, an anaerobic zone, and an aerobic zone. The anoxic zone, the anaerobic zone, and the aerobic zone are hydraulically connected sequentially, and the aerobic zone is connected to the anoxic zone. 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.

[0005] 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 anoxic zone, and the separation and sedimentation device being located in the second aerobic zone.

[0006] In one embodiment, the wastewater treatment retrofit system further includes an aeration pipe located at the bottom of the aerobic zone.

[0007] In one embodiment, the wastewater treatment modification system further includes a first agitator located at the bottom of the anoxic zone; and / or, the wastewater treatment modification system further includes a second agitator located at the bottom of the anaerobic zone.

[0008] In one embodiment, the wastewater treatment modification system further includes an inlet pipe for inputting wastewater into at least one of the anoxic zone and the anaerobic zone.

[0009] 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.

[0010] 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.

[0011] In one embodiment, the lower gas collection hood has a first inlet and a first outlet, and the upper gas collection hood has a second inlet and a second outlet. The first inlet, the first outlet, the second inlet, and the second outlet are connected sequentially from bottom to top, and the second outlet is connected to the gas collection pipe. The size of the first inlet is larger than the size of the first outlet, and the size of the second inlet is larger than the size of the second outlet.

[0012] In one embodiment, the aerobic zone is provided with a reflux port, the aerobic zone is connected to the anoxic zone through the reflux port, and the outlet of the gas collecting pipe is located below the reflux port.

[0013] Secondly, this application also provides a modification method based on SBR or CASS processes, the modification method comprising: In the SBR or CASS process tank, a first partition wall and a second partition wall are installed to physically divide the tank into anoxic zone, anaerobic zone and aerobic zone arranged in sequence. The anoxic zone, the anaerobic zone, and the aerobic zone are hydraulically connected sequentially, and the anoxic zone and the aerobic zone are hydraulically connected as well. A separation and sedimentation device is installed in the aerobic zone to achieve mud-water separation and obtain clarified water, so that the aerobic zone becomes an aerobic sedimentation coupling zone.

[0014] Compared with the prior art, the beneficial effects of this application are as follows: The wastewater treatment retrofit system provided in this application is based on the modification of traditional SBR or CASS process systems. Specifically, on the basis of the original SBR or CASS process tank, a first partition wall and a second partition wall are installed to physically divide the tank into anoxic, anaerobic, and aerobic zones. The anoxic, anaerobic, and aerobic zones are hydraulically connected end to end. In addition, a separation and sedimentation device is installed in the aerobic zone, making the aerobic zone an aerobic sedimentation coupling zone. This aerobic sedimentation coupling zone can not only realize the aerobic reaction between activated sludge and wastewater, but also realize the separation of sludge and water using the separation and sedimentation device. Thus, the wastewater treatment retrofit system of this application is obtained. Compared to SBR or CASS processes, the modified wastewater treatment system is divided into multiple reaction zones: anoxic, anaerobic, and aerobic zones. Each reaction zone performs its own function, enabling the system to achieve continuous treatment. This avoids the problems of SBR or CASS processes, which require precise switching between each stage (influent, aeration, sedimentation, and effluent) and are highly dependent on automation. In other words, the modified wastewater treatment system has a lower degree of automation, is simpler to control, and improves the utilization rate of tank volume, increasing the system's treatment capacity by 50% to 100% compared to before the modification. Attached Figure Description

[0015] 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.

[0016] Figure 1 A perspective view of the wastewater treatment retrofit system provided in the embodiments of this application.

[0017] Figure 2 A schematic diagram of a wastewater treatment retrofit system provided in an embodiment of this application.

[0018] Figure 3 A schematic diagram of a separation and precipitation device set up in an aerobic zone, provided in an embodiment of this application.

[0019] Figure 4 A simplified schematic diagram illustrating the working principle of the separation and precipitation device provided in the embodiments of this application.

[0020] Figure 5 This is a schematic diagram of the separation component in the separation and precipitation apparatus provided in the embodiments of this application.

[0021] Explanation of key figure labels: Reaction tank 10, tank body 11, first partition wall 12, second partition wall 13, anoxic zone A1, anaerobic zone A2, aerobic zone A3, first aerobic zone A31, second aerobic zone A32, separation and sedimentation device 20, frame assembly 21, separation assembly 22, gas collection pipe 221, upper gas collection hood 222, third inclined plate 2221, fourth inclined plate 2222, lower gas collection hood 223, first inclined plate 2231, second inclined plate 2232, effluent weir 23, first flow channel Y1, second flow channel Y2, third flow channel Y3, first inlet X1, first outlet X2, second inlet X3, second outlet X4, return port X5, containment space X6, air outlet X7, aeration pipe 30, first stirrer 40, second stirrer 50, connecting pipe 60, inlet pipe 70. Detailed Implementation

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.

[0028] Please refer to Figure 1 This application provides a wastewater treatment retrofit system based on SBR or CASS process, the wastewater treatment retrofit system including: reaction tank 10 and separation sedimentation device 20.

[0029] The reaction tank 10 includes a tank body 11, a first partition wall 12, and a second partition wall 13. The first partition wall 12 and the second partition wall 13 are both located inside the tank body 11 and are spaced apart from each other to physically divide the tank body 11 into anoxic zone A1, anaerobic zone A2, and aerobic zone A3. The anoxic zone A1, the anaerobic zone A2, and the aerobic zone A3 are hydraulically connected in sequence, and the aerobic zone A3 is connected to the anoxic zone A1.

[0030] Separation and sedimentation device 20 is provided in the aerobic zone A3. The separation and sedimentation device 20 is used to separate mud and water to obtain clarified water, so that the aerobic zone A3 becomes an aerobic sedimentation coupling zone.

[0031] Among them, the anoxic zone A1 is 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.

[0032] Among them, the anaerobic zone A2 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 the subsequent excessive phosphorus uptake in the aerobic zone A3.

[0033] The aerobic zone A3 is used to oxidize organic matter, nitrify ammonia nitrogen, and absorb excess phosphorus. Under aeration and oxygenation conditions, aerobic bacteria in the activated sludge completely oxidize and decompose the remaining organic matter in the wastewater; nitrifying bacteria in the activated sludge convert ammonia nitrogen in the wastewater into nitrate nitrogen; at the same time, polyphosphate-accumulating bacteria in the activated sludge utilize the energy stored in the anaerobic zone A2 to absorb excess phosphorus from the wastewater into their bodies, thereby achieving efficient removal of pollutants.

[0034] In practical applications, the mixed liquor of wastewater and activated sludge flows from the anoxic zone A1 to the anaerobic zone A2, and then from the anaerobic zone A2 to the aerobic zone A3. The aerobic zone A3 has two flow directions: first, a portion of the mixed liquor flows back to the anoxic zone A1; second, a portion enters the separation and sedimentation device 20. The activated sludge settles in the lower part of the separation and sedimentation device 20, 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 A3, equipped with the separation and sedimentation device 20, not only enables aerobic reactions between activated sludge and wastewater but also achieves sludge-water separation, making it essentially an aerobic sedimentation coupling zone. It should be noted that the number of separation and sedimentation devices 20 set in the aerobic zone A3 can be one or more. For example, the number of separation and sedimentation devices 20 can be 1, 2, 3, 4, 5, etc. This application only uses 2 as an example.

[0035] The wastewater treatment retrofit system provided in this application is based on the modification of a traditional SBR or CASS process system. Specifically, on the basis of the original tank 11 of the SBR or CASS process, a first partition wall 12 and a second partition wall 13 are set to physically divide the tank 11 into anoxic zone A1, anaerobic zone A2, and aerobic zone A3. The anoxic zone A1, anaerobic zone A2, and aerobic zone A3 are hydraulically connected end to end. In addition, a separation sedimentation device 20 is set in the aerobic zone A3, making the aerobic zone A3 an aerobic sedimentation coupling zone. This aerobic sedimentation coupling zone can not only realize the aerobic reaction between activated sludge and wastewater, but also realize the separation of sludge and water using the separation sedimentation device 20. Thus, the wastewater treatment retrofit system of this application is obtained. Compared to SBR or CASS processes, the modified wastewater treatment system is divided into multiple reaction zones: anoxic zone A1, anaerobic zone A2, and aerobic zone A3. Each reaction zone performs its own function, enabling the system to achieve continuous treatment. This avoids the problems of SBR or CASS processes, which require precise switching between each stage (influent, aeration, sedimentation, and effluent) and are highly dependent on automation. In other words, the modified wastewater treatment system has a lower degree of automation, is simpler to control, and has a significantly improved treatment capacity. It also improves the utilization rate of tank volume, increasing the system's treatment capacity by 50% to 100% compared to before the modification.

[0036] Please refer to Figure 2 In one embodiment, the aerobic zone A3 includes a first aerobic zone A31 and a second aerobic zone A32. The first aerobic zone A31 is hydraulically connected to the anaerobic zone A2, and the second aerobic zone A32 is hydraulically connected to the anoxic zone A1. The separation and sedimentation device 20 is located in the second aerobic zone A32.

[0037] In this system, the first aerobic zone A31 and the second aerobic zone A32 are not physically separated; they are simply different areas within the aerobic zone A3. In one embodiment, the volume of the first aerobic zone A31 is exactly the same as the volume of the second aerobic zone A32; in another embodiment, the volume of the first aerobic zone A31 is larger than the volume of the second aerobic zone A32; and in yet another embodiment, the volume of the first aerobic zone A31 is smaller than the volume of the second aerobic zone A32. Placing the separation and sedimentation device 20 in the second aerobic zone A32 ensures that the wastewater and activated sludge first fully contact and react in the first aerobic zone A31 before entering the separation and sedimentation device 20 to obtain clarified water, thus guaranteeing better water quality.

[0038] Please refer to Figure 2 In one embodiment, the wastewater treatment modification system further includes an aeration pipe 30, which is disposed at the bottom of the aerobic zone A3.

[0039] The aeration pipe 30 is simultaneously located within the first aerobic zone A31 and the second aerobic zone A32. The aeration pipe 30 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 introduced into the main pipe and then released from the branch pipes into the aerobic zone A3 to provide oxygen to the aerobic microorganisms. When the aeration pipe 30 aerates, it generates a large number of bubbles. These bubbles, as they rise, disturb the water flow, allowing the wastewater, activated sludge, and oxygen to mix thoroughly, thus ensuring sufficient contact and reaction between the activated sludge and the wastewater.

[0040] Please refer to Figure 2 In one embodiment, the wastewater treatment modification system further includes a first agitator 40, which is located at the bottom of the anoxic zone A1. The first agitator 40 is used to agitate the mixed liquid in the anoxic zone A1 to ensure that the activated sludge and wastewater fully contact and react, preventing excessive activated sludge from settling to the bottom, thereby ensuring that the wastewater treatment capacity is at an ideal level.

[0041] Please refer to Figure 2 In one embodiment, the wastewater treatment modification system further includes a second agitator 50, which is located at the bottom of the anaerobic zone A2. The second agitator 50 is used to agitate the mixed liquor in the anaerobic zone A2 to ensure that the activated sludge and wastewater fully contact and react, preventing excessive activated sludge from settling to the bottom, thereby ensuring that the wastewater treatment capacity is at an ideal level.

[0042] Please refer to Figure 2In one embodiment, the wastewater treatment system further includes a connecting pipe 60, with its two ends connected to the aerobic zone A3 and the anoxic zone A1, respectively. The connecting pipe 60 is used to return the sludge-water mixture from the aerobic zone A3 to the anoxic zone A1, enabling the entire wastewater treatment system to circulate. The connecting pipe 60 has a first end and a second end. The first end connects to the aerobic zone A3, and the second end connects to the anoxic zone A1. The first end can be located at the top, middle, or bottom of the aerobic zone A3 in the height direction. Similarly, the second end can also be located at the top, middle, or bottom of the anoxic zone A1 in the height direction.

[0043] Please refer to Figure 2 In one embodiment, the wastewater treatment modification system further includes an inlet pipe 70 for inputting wastewater into at least one of the anoxic zone A1 and the anaerobic zone A2.

[0044] In one embodiment, the water inlet pipe 70 includes a first water inlet end, which is located above the anoxic zone A1 to input sewage into the anoxic zone A1.

[0045] In another embodiment, the inlet pipe 70 includes a second inlet end, which is located above the anaerobic zone A2 to input wastewater into the anaerobic zone A2.

[0046] In another embodiment, the water inlet pipe 70 includes a first water inlet end and a second water inlet end. The first water inlet end is located above the anoxic zone A1 to input sewage into the anoxic zone A1, and the second water inlet end is located above the anaerobic zone A2 to input sewage into the anaerobic zone A2.

[0047] Please refer to Figure 3 In one embodiment, the separation and sedimentation device 20 includes a frame assembly 21, a separation assembly 22, and an outlet weir 23. The frame assembly 21 has a receiving space X6. The separation assembly 22 and the outlet weir 23 are both disposed within the receiving space X6, with the outlet weir 23 located at the top of the receiving space X6 and the separation assembly 22 located below the outlet weir 23. The separation assembly 22 is used to achieve mud-water separation to form clarified water above the separation assembly 22, and the outlet weir 23 is used to collect the clarified water.

[0048] The frame assembly 21 can be composed of multiple partitions, the material of which can be, but is not limited to, stainless steel, fiberglass, polyethylene, etc. Multiple partitions are connected end-to-end to enclose the containing space X6. The projection shape of the containing space X6 on the ground can be, but is not limited to, circular, angular, elliptical, etc. The containing space X6 is divided into a first region and a second region from bottom to top. The separation assembly 22 is located in the first region, and the effluent weir 23 is located at the top of the second region. The first region is connected to the aerobic zone A3, meaning that the mixed liquor in the aerobic zone A3 can enter the first region. When the mixed liquor enters the first region from the aerobic zone A3, the separation assembly 22 functions, causing the activated sludge to settle downwards, achieving sludge-water separation, thus resulting in clarified water in the second region. This clarified water is collected by the effluent weir 23 and then discharged from the system.

[0049] The top of the frame assembly 21 can be flush with or exceed the top of the aerobic zone A3 tank 11. This arrangement is to prevent mixed liquid outside the separation and sedimentation device 20 from flowing into the clarified water from the top of the frame assembly 21 and contaminating it.

[0050] Please refer to Figure 3 and Figure 4 In one embodiment, the separation component 22 includes a gas collecting pipe 221, a plurality of upper gas collecting hoods 222, and a plurality of lower gas collecting hoods 223 arranged sequentially from top to bottom. The plurality of upper gas collecting hoods 222 and the plurality of lower gas collecting hoods 223 are arranged laterally at intervals, and the upper gas collecting hoods 222 and the lower gas collecting hoods 223 are arranged in a one-to-one correspondence. The gas collecting pipe 221, the upper gas collecting hoods 222, and the lower gas collecting hoods 223 are connected sequentially.

[0051] A first flow channel Y1 is formed by a gap between adjacent upper gas collecting hoods 222 and lower gas collecting hoods 223. A second flow channel Y2 is formed by a gap between two adjacent lower gas collecting hoods 223. A third flow channel Y3 is formed by a gap between two adjacent upper gas collecting hoods 222.

[0052] In practical applications, the bubbles generated by aeration at the bottom of the aerobic zone A3 via aeration pipe 30 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 20 will first carry the mixed liquid into the lower gas collection hood 223, and then into the upper gas collection hood 222. The bubbles and mixed liquid entering the upper gas collection hood 222 will then diverge into two paths. The bubbles will continue to rise until they reach the gas collection pipe 221, where the gas will be collected, while the mixed liquid will flow out from the first flow channel Y1. The mixed liquid flowing out from the first channel Y1 will be divided into two paths again. As the bubbles rise, they carry some of the mixed liquid away from the aerobic zone A3 and move upward. Therefore, some of the mixed liquid will flow from the first channel Y1 to the second channel Y2 and move downward to the aerobic zone A3 (the first flow path) to supplement the aerobic zone A3 below the separation and sedimentation device 20. At the same time, as the effluent weir 23 continuously discharges the clarified water from the top of the separation and sedimentation device 20, some of the mixed liquid will flow from the first channel Y1 to the third channel Y3 and move upward to the effluent weir 23 (the second flow path). In the process of the mixed liquor flowing through the second flow path, the activated sludge will settle under the influence of weight as it moves upward, forming clarified water above the separation component 22. The settled activated sludge will fall and accumulate between the two adjacent lower gas collection hoods 223 or on top of the lower gas collection hoods 223. Therefore, the mixed liquor flowing through the first flow path will carry away this settled and accumulated activated sludge, allowing this portion of the activated sludge to return to the aerobic zone A3 below the separation and sedimentation device 20. Furthermore, after this portion of activated sludge settles and accumulates, its concentration ratio will decrease, making the activated sludge easier to settle, i.e., easier to achieve sludge-water separation. It can be understood that after the mixed liquor flowing through the first flow path returns to the aerobic zone A3, it will re-enter the separation and sedimentation device 20 with the air bubbles, thus forming a hydraulic cycle inside and outside the lower gas collection hood 223.

[0053] Please refer to Figure 4 and Figure 5In one embodiment, the lower gas collecting hood 223 has a first inlet X1 and a first outlet X2, and the upper gas collecting hood 222 has a second inlet X3 and a second outlet X4. The first inlet X1, the first outlet X2, the second inlet X3, and the second outlet X4 are sequentially connected from bottom to top, and the second outlet X4 is connected to the gas collecting pipe 221. During the rising process, the bubbles will sequentially enter the gas collecting pipe 221 through the first inlet X1, the first outlet X2, the second inlet X3, and the second outlet X4 to be collected. The size of the first inlet X1 is larger than the size of the first outlet X2, and the size of the second inlet X3 is larger than the size of the second outlet X4. That is, both the lower gas collecting hood 223 and the upper gas collecting hood 222 have a structure that gradually narrows from bottom to top, which facilitates the gradual collection of gas into the gas collecting pipe 221. It should be noted that the lower gas collecting hood 223 and the upper gas collecting hood 222 only need to meet the above-mentioned narrowing requirements; their specific shapes can be trapezoidal, conical, etc., and are not limited here.

[0054] Please refer to Figure 5 In one embodiment, the lower gas collection hood 223 includes a first inclined plate 2231 and a second inclined plate 2232, both of which are inclined to form a first inlet X1 and a first outlet X2. It is understood that the inclined arrangement of the first inclined plate 2231 and the second inclined plate 2232 facilitates the sliding of activated sludge settling on the top of the first inclined plate 2231 and the second inclined plate 2232 between the two adjacent lower gas collection hoods 223, thereby making it easier for the mixed liquid flowing through the first flow path to carry away this settled and accumulated activated sludge.

[0055] Please refer to Figure 5 In one embodiment, the upper gas collection hood 222 includes a third inclined plate 2221 and a fourth inclined plate 2222, both of which are inclined to form a second inlet X3 and a second outlet X4. It is understood that the inclined arrangement of the third inclined plate 2221 and the fourth inclined plate 2222 facilitates the sliding of activated sludge settled on the top of the third inclined plate 2221 and the fourth inclined plate 2222 onto the top of the lower gas collection hood 223, and then from the top of the lower gas collection hood 223 down between two adjacent lower gas collection hoods 223. This allows the mixed liquid flowing through the first flow path to carry away this settled and accumulated activated sludge.

[0056] Please refer to Figure 4 and Figure 5 In one embodiment, the aerobic zone A3 is provided with a return port X5, and the aerobic zone A3 is connected to the hypoxic zone A1 through the return port X5, that is, the return port X5 is connected to the connecting pipe 60. The gas collecting pipe 221 extends out of the frame assembly 21 and the gas outlet X7 of the gas collecting pipe 221 is located below the return port X5.

[0057] In practical applications, the gas collected by the gas collecting pipe 221 is discharged from the gas outlet X7. 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 X7 of the gas collecting pipe 221 is located below the return port X5, the rising bubbles can facilitate the flow of the mixed liquid from the aerobic zone A3 into the anoxic zone A1. Thus, no additional power source is needed to drive the mixed liquid from the aerobic zone A3 to the anoxic zone A1, or the driving force of the power source can be reduced, thereby achieving energy savings. The number of gas outlets X7 can be one or more, for example, 1, 2, 3, 4, 5, or 6.

[0058] Optionally, the gas collecting pipes 221 in each separation and sedimentation device 20 are connected. This arrangement allows the gas collecting pipes 221 to collect more gas, which makes it easier to determine the direction of the mixed liquid flow to the return port X5.

[0059] This application also provides a modification method based on SBR or CASS process, the modification method including steps S100, S200 and S300, the details of steps S100, S200 and S300 are as follows.

[0060] S100: A first partition wall 12 and a second partition wall 13 are installed in the tank of the SBR or CASS process to physically divide the tank into anoxic zone A1, anaerobic zone A2 and aerobic zone A3 arranged in sequence.

[0061] S200: Hydraulically connect the anoxic zone A1, the anaerobic zone A2, and the aerobic zone A3 in sequence, and hydraulically connect the anoxic zone A1 and the aerobic zone A3.

[0062] S300: A separation and sedimentation device 20 is installed in the aerobic zone A3. The separation and sedimentation device 20 is used to separate mud and water to obtain clarified water, so that the aerobic zone A3 becomes an aerobic sedimentation coupling zone.

[0063] For the modified anoxic zone A1, anaerobic zone A2, aerobic zone A3 (aerobic precipitation coupling zone), separation and precipitation device 20, 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, and S300; each step can be performed simultaneously or sequentially. For example, the order of the modification method can be S100, S200, S300, or it can be S300, S200, S100, etc.

[0064] 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 sewage treatment retrofit system based on SBR or CASS process, characterized in that, The wastewater treatment retrofit system includes: A reaction tank (10) includes a tank body (11), a first partition wall (12), and a second partition wall (13). The first partition wall (12) and the second partition wall (13) are both located within the tank body (11) and are spaced apart from each other, so as to physically divide the tank body (11) into anoxic zone (A1), anaerobic zone (A2), and aerobic zone (A3). The anoxic zone (A1), the anaerobic zone (A2), and the aerobic zone (A3) are hydraulically connected in sequence, and the aerobic zone (A3) is connected to the anoxic zone (A1). Separation and sedimentation device (20) is located in the aerobic zone (A3). The separation and sedimentation device (20) is used to separate mud and water to obtain clarified water, so that the aerobic zone (A3) becomes an aerobic sedimentation coupling zone.

2. The wastewater treatment retrofit system as described in claim 1, characterized in that, The aerobic zone (A3) includes a first aerobic zone (A31) and a second aerobic zone (A32). The first aerobic zone (A31) is hydraulically connected to the anaerobic zone (A2), and the second aerobic zone (A32) is hydraulically connected to the anoxic zone (A1). The separation and sedimentation device (20) is located in the second aerobic zone (A32).

3. The wastewater treatment retrofit system as described in claim 1, characterized in that, The wastewater treatment renovation system also includes an aeration pipe (30), which is located at the bottom of the aerobic zone (A3).

4. The wastewater treatment retrofit system as described in claim 1, characterized in that, The wastewater treatment renovation system further includes a first agitator (40), which is located at the bottom of the anoxic zone (A1); and / or, the wastewater treatment renovation system further includes a second agitator (50), which is located at the bottom of the anaerobic zone (A2).

5. The wastewater treatment retrofit system as described in claim 1, characterized in that, The wastewater treatment renovation system also includes an inlet pipe (70) for inputting wastewater into at least one of the anoxic zone (A1) and the anaerobic zone (A2).

6. The wastewater treatment renovation system as described in any one of claims 1 to 5, characterized in that, The separation and sedimentation device (20) includes a frame assembly (21), a separation assembly (22), and an outlet weir (23). The frame assembly (21) has a receiving space (X6). The separation assembly (22) and the outlet weir (23) are both located in the receiving space (X6), and the outlet weir (23) is located at the top of the receiving space (X6). The separation assembly (22) is located below the outlet weir (23). The separation assembly (22) is used to achieve mud-water separation to form clear water above the separation assembly (22). The outlet weir (23) is used to collect the clear water.

7. The wastewater treatment retrofit system as described in claim 6, characterized in that, The separation component (22) includes a gas collecting pipe (221), multiple upper gas collecting hoods (222), and multiple lower gas collecting hoods (223) arranged sequentially from top to bottom. The multiple upper gas collecting hoods (222) and the multiple lower gas collecting hoods (223) are arranged horizontally at intervals, and the upper gas collecting hoods (222) and the lower gas collecting hoods (223) are arranged in a one-to-one correspondence. The gas collecting pipe (221), the upper gas collecting hoods (222), and the lower gas collecting hoods (223) are connected sequentially.

8. The wastewater treatment retrofit system as described in claim 7, characterized in that, The lower gas collection hood (223) has a first inlet (X1) and a first outlet (X2), and the upper gas collection hood (222) has a second inlet (X3) and a second outlet (X4). The first inlet (X1), the first outlet (X2), the second inlet (X3) and the second outlet (X4) are connected sequentially from bottom to top, and the second outlet (X4) is connected to the gas collection pipe (221). The size of the first inlet (X1) is larger than the size of the first outlet (X2), and the size of the second inlet (X3) is larger than the size of the second outlet (X4).

9. The wastewater treatment retrofit system as described in claim 7, characterized in that, The aerobic zone (A3) is provided with a return port (X5), and the aerobic zone (A3) is connected to the hypoxic zone (A1) through the return port (X5). The outlet (X7) of the gas collecting pipe (221) is located below the return port (X5).

10. A modification method based on SBR or CASS process, characterized in that, The modification method includes: A first partition wall (12) and a second partition wall (13) are installed in the tank of the SBR or CASS process to physically divide the tank into anoxic zone (A1), anaerobic zone (A2) and aerobic zone (A3) arranged in sequence. The anoxic zone (A1), the anaerobic zone (A2), and the aerobic zone (A3) are hydraulically connected in sequence, and the anoxic zone (A1) and the aerobic zone (A3) are hydraulically connected. A separation and sedimentation device (20) is installed in the aerobic zone (A3). The separation and sedimentation device (20) is used to separate mud and water to obtain clarified water, so that the aerobic zone (A3) becomes an aerobic sedimentation coupling zone.

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