AOAO process integrated sewage treatment device and treatment process

Abstract

The invention relates to an AOAO process integrated sewage treatment device and a treatment process, on the basis of arranging an equipment room, an anaerobic tank, an aerobic tank and an anoxic tank, a secondary aerobic tank and a swing tank are also arranged, the swing tank is configured to be a switchable process, and the swing tank is arranged in the anoxic tank. The flexible and controllable retention time of the anaerobic or aerobic treatment process, the aerobic or anoxic treatment process and the anoxic or secondary aerobic treatment process is realized. The secondary sedimentation tank is used for separating sludge-water mixed liquid of the secondary aerobic tank, settled sludge respectively flows back to the anaerobic tank, the aerobic tank and the anoxic tank in a sludge three-reflux mode, and the sludge concentration of the anaerobic tank, the aerobic tank and the anoxic tank is easier and more flexible to adjust. Therefore, the residence time and the sludge concentration of the reaction tank can be greatly regulated and controlled, large water quality and water quantity fluctuation can be adapted by regulating and controlling process parameters, the functions of internal carbon source conversion, carbon reduction, nitrification, nitrogen removal and phosphorus removal can be better achieved, and the actual operation effect of a sewage treatment device and a treatment process can reach ideal indexes.

Description

Technical Field

[0001] The present application belongs to the technical field of sewage treatment, and in particular relates to an AOAO process integrated sewage treatment device and treatment process. Background Art

[0002] The sludge double-recirculation AOA process (i.e., anaerobic, aerobic, and anoxic process) is a new technology for deep denitrification of municipal wastewater and reduces carbon source addition. It offers advantages such as low energy consumption, minimal need for external carbon source addition, and excellent denitrification for wastewater with a low carbon-to-nitrogen ratio. However, this process requires high operational standards, especially when water quality and quantity fluctuate significantly. Timely adjustment of operating parameters in each reactor is necessary to ensure treatment effectiveness.

[0003] The anoxic tank, which uses an internal carbon source for denitrification, requires a longer residence time than anoxic tanks that typically use external carbon sources such as sodium acetate. Consequently, the anoxic tank is prone to anaerobic phosphorus release, leading to elevated total phosphorus levels in the effluent. Furthermore, denitrification causes nitrogen to be present in the activated sludge flocs, resulting in poor sludge settling performance and, in turn, an increase in suspended solids concentration in the effluent from the secondary sedimentation tank.

[0004] The sludge return mostly adopts single return mode and double return mode. In double return mode, the sludge generally only flows back to the anaerobic tank and the anoxic tank. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: to solve the problems in the prior art that the AOA process has high requirements for the control of the operating parameters of each reaction tank, the sludge settling performance is poor, and the actual operating effect is difficult to guarantee when the water quality and water volume fluctuate greatly, thereby providing an AOAO process integrated sewage treatment device and treatment process.

[0006] The technical solution adopted by the present invention to solve its technical problem is: An AOAO process integrated sewage treatment device, comprising: an anaerobic tank, an aerobic tank, an anoxic tank, a secondary aerobic tank and a secondary sedimentation tank arranged in sequence; the anaerobic tank is used to perform an anaerobic treatment process, the aerobic tank is used to perform an aerobic treatment process, the anoxic tank is used to perform an anoxic treatment process, and the secondary aerobic tank is used to blow off nitrogen and absorb excess phosphorus; the secondary sedimentation tank is used to separate the mud-water mixture in the secondary aerobic tank, the supernatant in the secondary sedimentation tank is discharged as effluent or deeply treated, and the precipitated sludge is returned to the anaerobic tank, the aerobic tank or the anoxic tank respectively; Also included is a swing tank, the swing tank being used to switchably perform one of two treatment processes, anaerobic or aerobic, or being used to switchably perform one of two treatment processes, anoxic or aerobic; The swing tank is arranged between the anaerobic tank and the aerobic tank, between the aerobic tank and the anoxic tank, and between the anoxic tank and the secondary aerobic tank.

[0007] Preferably, in the AOAO process integrated sewage treatment device of the present invention, the projection shapes of the anaerobic tank, the aerobic tank, the anoxic tank, the secondary aerobic tank and the swing tank in the top view direction are regular and uniform, and can be spliced ​​and connected to each other.

[0008] Preferably, in the AOAO process integrated sewage treatment device of the present invention, the plurality of anaerobic tanks, the plurality of aerobic tanks, the plurality of anoxic tanks, the plurality of secondary aerobic tanks and the plurality of swing tanks are arranged in an S shape.

[0009] Preferably, in the AOAO process integrated sewage treatment device of the present invention, there are three anaerobic tanks and three aerobic tanks; along the arrangement path, the anaerobic tanks are sequentially spliced, the aerobic tanks are sequentially spliced, and one swing tank is spliced ​​between the anaerobic tank and the aerobic tank; There are four anoxic pools arranged, and along the arrangement path, the anoxic pools are sequentially spliced, and two swing pools are spliced ​​between the anoxic pool and the aerobic pool; There is one secondary aerobic pool, and along the arrangement path, one swing pool is spliced ​​between the secondary aerobic pool and the anoxic pool.

[0010] Preferably, in the AOAO process integrated sewage treatment device of the present invention, the upper half of the secondary sedimentation tank is square and the lower half is circular, and a rotating scraper and a sludge hopper are provided in the center of the secondary sedimentation tank, and the sludge hopper is located below the rotating scraper.

[0011] Preferably, the AOAO process integrated sewage treatment device of the present invention further comprises an equipment room, in which a Roots blower, a first sludge return pump, a second sludge return pump, a third sludge return pump, a residual sludge pump and an electric control box are placed; The first sludge return pump, the second sludge return pump and the third sludge return pump are used to return the sludge in the sludge hopper to the anaerobic tank, the aerobic tank and the anoxic tank respectively; the second sludge return pump is also used to return the sludge to the anaerobic tank; the residual sludge pump is used to continuously or periodically discharge the residual sludge in the sludge hopper.

[0012] Preferably, the AOAO process integrated sewage treatment device of the present invention further includes: A mechanical stirrer is provided in the anaerobic tank, the anoxic tank and the swing tank; the mechanical stirrer is also provided in some of the aerobic tanks to control the dissolved oxygen in the aerobic tanks; An aeration device is arranged in the aerobic tank, the secondary aerobic tank and the swing tank.

[0013] Preferably, the AOAO process integrated sewage treatment process of the present invention uses the above-mentioned AOAO process integrated sewage treatment device to treat sewage, comprising the following steps: Presetting the treatment process of each swing tank according to the treatment expectations of the anaerobic tank, the aerobic tank, the anoxic tank and the secondary aerobic tank; Alternatively, the treatment process of each swing tank is adjusted in real time according to the treatment conditions of the anaerobic tank, the aerobic tank, the anoxic tank and the secondary aerobic tank.

[0014] Preferably, the AOAO process integrated sewage treatment process of the present invention divides the swing pool and the aerobic pool arranged in sequence into a first area, a second area and a third area in sequence, and controls the dissolved oxygen distribution of the corresponding areas from high to low according to the arrangement order. The first area controls the dissolved oxygen to 2.0~4.0 mg / L, and performs carbonization reaction and partial nitrification reaction on the sewage; the second area controls the dissolved oxygen to 0.8~2.0 mg / L, and performs nitrification reaction on the sewage; the third area reduces the aeration volume relative to the first area and the second area and runs a mechanical stirrer to control the dissolved oxygen to 0.5~0.8 mg / L, and couples the simultaneous nitrification and denitrification reaction. If the residence time of the anoxic pool exceeds the expected time, the swing pool (5) between the anoxic pool and the aerobic pool is allocated to the third area; the third area also reserves a small amount of sewage to be introduced as a supplementary alternative carbon source; The nitrogen in the activated sludge flocs is blown off through the secondary aerobic tank, and the residence time is about 45-60 minutes, of which the residence time for blow-off is 10-30 minutes, and the remaining residence time is used for aerobic excess phosphorus absorption to control the dissolved oxygen at 1.0 mg / L-3.0 mg / L.

[0015] Preferably, the AOAO process integrated sewage treatment process of the present invention further comprises a sludge return step: In the secondary sedimentation tank, the return rate of a single type of sludge is calculated as 50-100%, the return rate of the anaerobic tank is 50-200%, the return rate of the aerobic tank is 50-200%, and the return rate of the anoxic tank is 50-300%; the residence time required for each reaction tank is shortened by increasing the sludge concentration of the anaerobic tank, the aerobic tank or the anoxic tank, and the residence time of each reaction tank is increased by reducing the sludge concentration of the anaerobic tank, the aerobic tank or the anoxic tank. The beneficial effects of the present invention are as follows: on the basis of arranging the equipment room, anaerobic tank, aerobic tank and anoxic tank, a secondary aerobic tank and a swing tank are also arranged. The swing tank is configured as a switchable process, which realizes the flexible control of the residence time of the anaerobic or aerobic, aerobic or anoxic, anoxic or secondary aerobic treatment process. The dissolved oxygen concentration between the aerobic tanks presents a gradient change from high to low, which further removes organic matter while coupling the simultaneous nitrification and denitrification reaction to make the denitrification efficiency higher. The secondary aerobic tank is mainly used to blow off nitrogen in the activated sludge flocs, improve the sedimentation performance of the activated sludge in the secondary sedimentation tank, and also has the effect of aerobic excess phosphorus absorption. The secondary sedimentation tank is used to separate the mud-water mixture of the secondary aerobic tank, and the supernatant is discharged as effluent or deeply treated. The precipitated sludge adopts a sludge three-return mode, and is returned to the anaerobic tank, aerobic tank and anoxic tank respectively, which makes it easier and more flexible to adjust the sludge concentration of the anaerobic tank, aerobic tank and anoxic tank. Therefore, the present invention largely realizes the controllable residence time and sludge concentration of the reaction tank, and can adapt to larger fluctuations in water quality and water volume by regulating process parameters, which is conducive to better realizing the functions of internal carbon source conversion, carbon reduction, nitrification, denitrification and phosphorus removal, so that the actual operation effect of the sewage treatment device and treatment process can reach ideal indicators. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The technical solution of the present application is further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 This is a top view of the structure of the AOAO process integrated sewage treatment device according to an embodiment of the present application; Figure 2 This is a schematic diagram of the sewage pumping pipeline layout of the AOAO process integrated sewage treatment device in an embodiment of the present application.

[0018] The reference numerals in the figures are: 1. Anaerobic tank; 2. Aerobic pool; 3. Anoxic pool; 4. Secondary aerobic pool; 5. Swing pool; 6. Secondary sedimentation tank; 7. Mud scraper; 8. Roots blower; 9. The first sludge return pump; 10. Second sludge return pump; 11. The third sludge return pump; 12. Residual sludge pump; 13. Electric control box; 14. Equipment room; 15. Mechanical mixer. DETAILED DESCRIPTION

[0019] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0020] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application 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 cannot be understood as limiting the scope of protection of the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0021] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0022] The technical solution of the present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. Example This embodiment provides an AOAO process integrated sewage treatment device, such as Figure 1 As shown, it includes, arranged in sequence: an anaerobic tank 1, an aerobic tank 2, an anoxic tank 3, a secondary aerobic tank 4 and a secondary sedimentation tank 6; the anaerobic tank 1 is used to perform an anaerobic treatment process, convert most of the organic matter in the sewage into an internal carbon source, and perform an anaerobic phosphorus release reaction, as well as a small amount of denitrification and denitrification; the aerobic tank 2 is used to perform an aerobic treatment process, further remove organic matter that cannot be converted into an internal carbon source in the anaerobic process, perform aerobic phosphorus absorption and nitrification reactions, and couple simultaneous nitrification and denitrification reactions; the anoxic tank 3 is used to perform an anoxic treatment process, and perform denitrification and denitrification using an internal carbon source; the secondary aerobic tank 4 is mainly used for blowing off nitrogen, and also has an aerobic excess phosphorus absorption function; the secondary sedimentation tank 6 is used to separate the mud-water mixture of the secondary aerobic tank, and the supernatant is discharged as effluent or deeply treated, and the settled sludge is returned to the anaerobic tank 1, the aerobic tank 2 and the anoxic tank 3 respectively.

[0023] The AOAO process integrated sewage treatment device provided by the embodiment further comprises a swing tank 5, which is used to switchably perform one of anaerobic or aerobic treatment processes, or is used to switchably perform one of anoxic or aerobic treatment processes; the swing tank 5 is arranged between the anaerobic tank 1 and the aerobic tank 2, between the aerobic tank 2 and the anoxic tank 3, and between the anoxic tank 3 and the secondary aerobic tank 4.

[0024] The AOAO process integrated sewage treatment device of the embodiment has the problems that there is a difference between the design inflow water quality and the actual inflow water quality and the fluctuation of the treatment water quantity, so that the residence time of the anaerobic tank 1, the aerobic tank 2 and the anoxic tank 3 of the AOAO process is not easy to determine accurately. The anaerobic tank 1 needs to ensure sufficient residence time, so that the organic matter of sewage can be maximally converted into internal carbon source, to leave for the anoxic tank 3 for denitrification as a carbon source, so that external carbon source does not need to be added. The role of the aerobic tank 2 is to continue carbonization of the organic matter which cannot be converted into internal carbon source in the anaerobic tank 1, to over-absorb phosphorus in the aerobic process, and to completely nitrify ammonia nitrogen. Therefore, the aerobic tank 2 must be controlled at a suitable residence time, and insufficient or excessively long residence time will have adverse effects. If the residence time is insufficient, complete nitrification cannot be achieved; if the residence time is excessively long, the organic matter which has been converted into internal carbon source will be excessively carbonized, resulting in insufficient carbon source in the anoxic tank 3, and additional carbon source needs to be added in the anoxic tank. This makes the process complicated and increases the process cost. The anoxic tank 3 denitrifies, and nitrogen gas is carried in the activated sludge floc, which makes the sludge settling performance poor, and further increases the suspended matter concentration of the secondary sedimentation tank effluent. When the anoxic tank 3 uses internal carbon source for denitrification, the residence time required for the internal carbon source to be converted into available organic matter is longer than the residence time required for additional addition of external carbon source such as sodium acetate. If the total nitrogen of the inflow is reduced, the residence time of the anoxic tank 3 is excessively long, which is easy to cause anaerobic phosphorus release, resulting in the phenomenon that the total phosphorus of the effluent is increased.

[0025] The AOAO process integrated sewage treatment device of this embodiment is arranged on the basis of the anaerobic tank 1, aerobic tank 2, and anoxic tank 3, and also arranges a secondary aerobic tank 4 and a swing tank 5. The swing tank 5 is configured as a switchable process, which realizes the flexible controllable residence time of the anaerobic or aerobic, aerobic or anoxic, anoxic or secondary aerobic treatment process. The dissolved oxygen concentration in the aerobic tank 2 shows a gradient change from high to low, while further removing organic matter, it couples the simultaneous nitrification and denitrification reaction. The simultaneous nitrification and denitrification can reduce the residence time of the anoxic tank 3. The secondary aerobic tank 4 mainly plays the role of blowing off nitrogen, improving the sedimentation performance of the activated sludge in the secondary sedimentation tank, and also has the function of aerobic excess phosphorus absorption. The three-circulation sludge mode is adopted to efficiently adjust the sludge concentration of the anaerobic tank 1, the aerobic tank 3 and the anoxic tank 3. Combined with the switchable process of the swing tank 5, it has a strong ability to control the process parameters and can adapt to large fluctuations in water quality and water volume. It is conducive to better realizing the internal carbon source conversion, carbon reduction, nitrification, denitrification and phosphorus removal functions, so that the actual operation effect of the sewage treatment device and treatment process can reach the ideal indicators.

[0026] AOAO process integrated sewage treatment device process principle: According to the activated sludge treatment process, this process is an AOAO process, namely anaerobic, aerobic, anoxic, and secondary aerobic process. The sewage enters the anaerobic tank 1, which undergoes an anaerobic treatment process and converts most of the organic matter into internal carbon sources in the anaerobic tank 1; the sewage enters the aerobic tank 2 through the anaerobic tank 1, further removes the organic matter that has not been converted into internal carbon sources in the anaerobic tank 1 and undergoes nitrification reaction, coupled with simultaneous nitrification and denitrification reactions. Synchronous nitrification and denitrification can reduce the residence time of the anoxic tank 3. The effluent from the aerobic tank 2 flows by gravity to the front end of the anoxic tank 3. The anoxic tank 3 uses the internal carbon source generated by anaerobically to carry out biological denitrification and denitrification, and then enters the secondary aerobic tank 4 to blow off the nitrogen brought by the activated sludge caused by denitrification in the anoxic tank 3. The secondary aerobic tank 4 also has the function of aerobic excess phosphorus absorption, and automatically and continuously discharges sludge through the secondary sedimentation tank 6 for biological phosphorus removal and discharge of excess sludge. The effluent from the secondary sedimentation tank 6 is discharged or deeply treated. The sludge in the secondary sedimentation tank 6 can be returned to the anaerobic tank 1, aerobic tank 2 and anoxic tank 3 respectively.

[0027] In an optional embodiment, if Figure 1 As shown, the anaerobic tank 1, aerobic tank 2, anoxic tank 3, secondary aerobic tank 4, and swing tank 5 have regular and uniform projections when viewed from above, allowing them to be connected and spliced ​​together. In this embodiment, the tanks are designed as modules with regular and uniform projections, which facilitates arrangement and transportation. This makes it suitable for small-scale sewage treatment and is also applicable to sewage treatment applications of other scales.

[0028] In an optional embodiment, if Figure 1 As shown, a number of anaerobic tanks 1, a number of aerobic tanks 2, a number of anoxic tanks 3, a number of secondary aerobic tanks 4 and a number of swing tanks 5 are arranged in an S shape.

[0029] In an optional embodiment, if Figure 1 As shown, there are three anaerobic tanks 1 and three aerobic tanks 2; along the arrangement path, the anaerobic tanks 1 are spliced ​​in sequence, the aerobic tanks 2 are spliced ​​in sequence, and a swing tank 5 is spliced ​​between the anaerobic tank 1 and the aerobic tank 2; there are four anoxic tanks 3, along the arrangement path, the anoxic tanks 3 are spliced ​​in sequence, and two swing tanks 5 are spliced ​​between the anoxic tank 3 and the aerobic tank 2; there is one secondary aerobic tank 4, and along the arrangement path, a swing tank 5 is spliced ​​between the secondary aerobic tank 4 and the anoxic tank 3. In this embodiment, the anaerobic tank 1, the aerobic tank 2, the anoxic tank 3, the secondary aerobic tank 4 and the swing tank 5 are counted and arranged according to the designated grids. The total number of grids is designed to be 15 grids. The total biochemical residence time is about 12 to 15 hours. The anaerobic tank 1 and the swing tank 5 performing the anaerobic process, the aerobic tank 2 and the swing tank 5 performing the aerobic process, the anoxic tank 3 and the swing tank 5 performing the anoxic process, and the secondary aerobic tank 4 are initially determined to occupy 3, 4, 7 and 1 grids respectively.

[0030] In an optional embodiment, if Figure 1 、 Figure 2 As shown, the upper half of the secondary sedimentation tank 6 is square and the lower half is circular. A rotating scraper 7 and a sludge hopper are provided in the center of the secondary sedimentation tank 6 , and the sludge hopper is located below the rotating scraper 7 .

[0031] In an optional embodiment, if Figure 1 、 Figure 2 As shown, the AOAO process integrated sewage treatment device of this embodiment also includes an equipment room 14, which houses a Roots blower 8, a first sludge return pump 9, a second sludge return pump 10, a third sludge return pump 11, a residual sludge pump 12, and an electrical control box 13. In this embodiment, by providing three independently operated return pumps, it is possible to facilitate the return of sewage from the secondary sedimentation tank 6 to each tank as needed, shorten the residence time of each reaction tank by increasing the sludge concentration in each reaction tank, and increase the residence time of each reaction tank by reducing the sludge concentration in each reaction tank, allowing the sludge concentration to be flexibly adjusted. The residual sludge pump 12 is used to continuously or periodically discharge the residual sludge in the sludge hopper.

[0032] In an optional embodiment, the AOAO process integrated sewage treatment device further includes: a mechanical mixer 15 and an aeration device. The mechanical mixer 15 is arranged in the anaerobic tank 1, the anoxic tank 3, and the swing tank 5; Figure 1 、 Figure 2As shown, along the arrangement order, the aerobic tank 2 of the second and third grids increases the mechanical agitator 15 while reducing the aeration amount in order to control the dissolved oxygen, preventing sludge from depositing in the aerobic tank after the aeration amount is reduced. The aeration device is arranged in the aerobic tank 2, the secondary aerobic tank 4 and the swing tank 5. In this embodiment, the anaerobic tank 1 and the anoxic tank 3 are configured with the mechanical agitator 15, which can facilitate the anaerobic treatment process and the anoxic treatment process, the aerobic tank 2 and the secondary aerobic tank 4 are configured with the aeration device, which can facilitate the aerobic treatment process, and the swing tank 5 is configured with both the mechanical agitator 15 and the aeration device, which can realize process switching. Optionally, the aeration device uses the Roots blower 8 for air supply.

[0033] The AOAO process integrated sewage treatment device of this embodiment has no underwater equipment except the mud scraper 7 arranged in the secondary sedimentation tank 6, which is convenient for maintenance and repair.

[0034] This embodiment provides an AOAO process integrated sewage treatment process, which uses the above-mentioned AOAO process integrated sewage treatment device for sewage treatment, including the following steps: According to the treatment expectations of the anaerobic tank 1, the aerobic tank 2, the anoxic tank 3 and the secondary aerobic tank 4, the treatment process of each swing tank 5 is preset; Or, according to the treatment of the anaerobic tank 1, the aerobic tank 2, the anoxic tank 3 and the secondary aerobic tank 4, the treatment process of each swing tank 5 is adjusted in real time.

[0035] In this embodiment, by presetting or adjusting the treatment process of the swing tank 5 in real time, the treatment capacity of the swing tank 5 can be matched with the current sewage treatment situation, so as to achieve an ideal sewage treatment effect.

[0036] In an optional embodiment, the AOAO process integrated sewage treatment process of this embodiment arranges the swing tanks 5 and the aerobic tanks 2 in sequence into a first region, a second region and a third region in sequence, controls the distribution of dissolved oxygen from high to low according to the arrangement order, controls the dissolved oxygen in the first region to be 2.0-4.0 mg / L, performs carbonization reaction and part of nitrification reaction on the sewage, controls the dissolved oxygen in the second region to be 0.8-2.0 mg / L, performs nitrification reaction on the sewage, reduces the aeration amount and operates the mechanical agitator in the third region relative to the first region and the second region, controls the dissolved oxygen to be 0.5-0.8 mg / L, and couples the simultaneous nitrification and denitrification reaction; if the residence time of the anoxic tank 3 exceeds the expected time, the swing tank 5 between the anoxic tank 3 and the aerobic tank 2 is allocated to the third region; the third region also reserves a small amount of sewage to be introduced as a supplementary alternative carbon source.

[0037] In an optional embodiment, the AOAO process integrated sewage treatment process of this embodiment further includes a sludge return step: in the secondary sedimentation tank 6, the return rate of a single sludge is calculated as 50~100%, the return rate of the anaerobic tank 1 is 50~200%, the return rate of the aerobic tank 2 is 50~200%, and the return rate of the anoxic tank 3 is 50~300%.

[0038] The process and device adopt a three-way sludge return mode to flexibly adjust the sludge concentration of each tank and improve the adaptability to different water quality and water quantity. The return of activated sludge can be operated in a single return mode, a double return mode and a triple return mode. The anaerobic tank (1), the aerobic tank (2), the anoxic tank (3) and the secondary aerobic tank (4) can operate with two or three different sludge concentrations. Assuming that the return sludge concentration of the secondary sedimentation tank is 8g / L, the sludge concentration MLSS is 2700mg / L when the return flow is 50%, 4000mg / L when the return flow is 100%, 5300mg / L when the return flow is 200%, and 6000mg / L when the return flow is 300%. The residence time of each reaction tank can be shortened by increasing the sludge concentration of each reaction tank, and the residence time of each reaction tank can be increased by reducing the sludge concentration of each reaction tank, so that the sludge concentration can be flexibly adjusted.

[0039] The adjustable retention time and sludge concentration in each tank maximize operational flexibility throughout the entire process, enabling flexible adjustments to each tank's internal carbon source conversion, carbon reduction, nitrification, denitrification, and phosphorus removal functions. Adjustable retention time and sludge concentration enhance adaptability to fluctuations in influent quality and quantity. For wastewater with a low carbon-nitrogen ratio, anaerobic tank 1 converts most organic matter into an internal carbon source. Aerobic tank 2, with its adjustable dissolved oxygen concentration, further removes any remaining organic matter that failed to be converted into an internal carbon source in anaerobic tank 1 and undergoes nitrification. This coupled simultaneous nitrification and denitrification reactions results in higher nitrogen removal efficiency without consuming excess internal carbon sources. Anoxic tank 3 utilizes the internal carbon source for denitrification, while carefully controlling the retention time to prevent anaerobic phosphorus release. The secondary aerobic tank 4, added after anoxic tank 3, primarily serves to remove nitrogen, promoting the formation of larger activated sludge flocs and improving sludge settling efficiency in secondary sedimentation tank 6. It also serves as an aerobic agent for excess phosphorus absorption.

[0040] In an optional embodiment, the secondary aerobic tank 4 strips nitrogen from the activated sludge flocs with a residence time of approximately 45 to 60 minutes, with 10 to 30 minutes of this stripping time. The remaining time is used for aerobic phosphorus absorption, controlling the dissolved oxygen level to 1.0 mg / L to 3.0 mg / L. Simultaneously, aeration overcomes the anaerobic phosphorus release caused by poorly controlled anoxic tank 3, allowing the released phosphorus to be reabsorbed. If the operating conditions of the anoxic tank 3 are properly controlled, excessive aerobic phosphorus absorption is unnecessary.

[0041] Based on the above-mentioned ideal embodiments of this application, and in accordance with the above description, relevant personnel can make various changes and modifications without departing from the scope of the technical concept of this application. The technical scope of this application is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An AOAO process integrated sewage treatment device, characterized in that: The invention comprises an anaerobic tank (1), an aerobic tank (2), an anoxic tank (3), a secondary aerobic tank (4) and a secondary sedimentation tank (6) arranged in sequence; the anaerobic tank (1) is used to perform an anaerobic treatment process, the aerobic tank (2) is used to perform an aerobic treatment process, the anoxic tank (3) is used to perform an anoxic treatment process, and the secondary aerobic tank (4) is used to blow off nitrogen and absorb excessive phosphorus; the secondary sedimentation tank (6) is used to separate the mud-water mixture of the secondary aerobic tank (4), the supernatant of the secondary sedimentation tank (6) is discharged as effluent or deeply treated, and the precipitated sludge is returned to the anaerobic tank (1), the aerobic tank (2) or the anoxic tank (3) respectively; It also includes a swing tank (5), which is used to switchably perform one of the two treatment processes of anaerobic or aerobic, or to switchably perform one of the two treatment processes of anoxic or aerobic; The swing tank (5) is arranged between the anaerobic tank (1) and the aerobic tank (2), between the aerobic tank (2) and the anoxic tank (3), and between the anoxic tank (3) and the secondary aerobic tank (4).

2. The AOAO process integrated sewage treatment device according to claim 1, characterized in that: The projection shapes of the anaerobic tank (1), the aerobic tank (2), the anoxic tank (3), the secondary aerobic tank (4), and the swing tank (5) in the top view direction are regular and uniform, and can be spliced ​​and connected to each other.

3. The AOAO process integrated sewage treatment device according to claim 2, characterized in that: A plurality of the anaerobic tanks (1), a plurality of the aerobic tanks (2), a plurality of the anoxic tanks (3), a plurality of the secondary aerobic tanks (4) and a plurality of the swing tanks (5) are arranged in an S shape.

4. The AOAO process integrated sewage treatment device according to claim 3, characterized in that: There are three anaerobic tanks (1) and three aerobic tanks (2); along the arrangement path, the anaerobic tanks (1) are sequentially connected, and the aerobic tanks (2) are sequentially connected, and one swing tank (5) is spliced ​​between the anaerobic tank (1) and the aerobic tank (2); There are four anoxic pools (3) arranged, and along the arrangement path, the anoxic pools (3) are sequentially connected, and two swing pools (5) are connected between the anoxic pool (3) and the aerobic pool (2); One secondary aerobic pool (4) is arranged, and along the arrangement path, one swing pool (5) is spliced ​​between the secondary aerobic pool (4) and the anoxic pool (3).

5. The AOAO process integrated sewage treatment device according to any one of claims 1 to 4, characterized in that: The upper half of the secondary sedimentation tank (6) is square, and the lower half is circular. A rotating scraper (7) and a sludge hopper are provided at the center of the secondary sedimentation tank (6), and the sludge hopper is located below the rotating scraper (7).

6. The AOAO process integrated sewage treatment device according to any one of claims 1 to 5, characterized in that: The AOAO process integrated sewage treatment device further comprises: an equipment room (14), wherein a Roots blower (8), a first sludge return pump (9), a second sludge return pump (10), a third sludge return pump (11), a residual sludge pump (12), and an electric control box (13) are placed in the equipment room (14); The first sludge return pump (9), the second sludge return pump (10) and the third sludge return pump (11) are used to return the sludge in the sludge hopper to the anaerobic tank (1), the aerobic tank (2) and the anoxic tank (3), respectively; the second sludge return pump (10) is also used to return the sludge to the anaerobic tank (1); The excess sludge pump (12) is used to discharge the excess sludge in the sludge hopper continuously or periodically.

7. The AOAO process integrated sewage treatment device according to any one of claims 1 to 6, characterized in that: Also includes: A mechanical stirrer (15) is provided in the anaerobic tank (1), the anoxic tank (3) and the swing tank (5); the mechanical stirrer (15) is also provided in part of the aerobic tank (2) for controlling the dissolved oxygen in the aerobic tank (2); An aeration device is provided in the aerobic tank (2), the secondary aerobic tank (4) and the swing tank (5).

8. An AOAO process integrated sewage treatment process, characterized in that: The AOAO process integrated sewage treatment device according to any one of claims 1 to 7 is used to treat sewage, comprising the following steps: Presetting the treatment process of each of the swing tanks (5) according to the treatment expectations of the anaerobic tank (1), the aerobic tank (2), the anoxic tank (3) and the secondary aerobic tank (4); Alternatively, the treatment process of each of the swing tanks (5) is adjusted in real time according to the treatment conditions of the anaerobic tank (1), the aerobic tank (2), the anoxic tank (3) and the secondary aerobic tank (4).

9. The AOAO process integrated sewage treatment process according to claim 8, characterized in that: The swing pool (5) and the aerobic pool (2) arranged in sequence are divided into a first area, a second area and a third area in sequence, and the dissolved oxygen distribution of the corresponding areas is controlled from high to low according to the arrangement order. The dissolved oxygen in the first area is controlled to be 2.0~4.0 mg / L, and the carbonization reaction and partial nitrification reaction of the sewage are carried out; the dissolved oxygen in the second area is controlled to be 0.8~2.0 mg / L, and the nitrification reaction of the sewage is carried out; the aeration volume in the third area is reduced relative to the first and second areas, and a mechanical mixer is operated to control the dissolved oxygen to be 0.5~0.8 mg / L, and a synchronous nitrification and denitrification reaction is coupled; if the residence time of the anoxic pool (3) exceeds the expected time, the swing pool (5) between the anoxic pool (3) and the aerobic pool (2) is allocated to the third area; a small amount of sewage is also reserved in the third area to be introduced as a supplementary alternative carbon source; The nitrogen in the activated sludge flocs is blown off through the secondary aerobic tank (4), and the residence time is about 45 to 60 minutes, of which the residence time for blow-off is 10 to 30 minutes, and the remaining residence time is used for aerobic excess phosphorus absorption to control the dissolved oxygen at 1.0 mg / L to 3.0 mg / L.

10. The AOAO process integrated sewage treatment process according to claim 8 or 9, characterized in that: Also includes sludge return step: In the secondary sedimentation tank (6), the return rate of a single type of sludge is calculated as 50-100%, the return rate of the anaerobic tank (1) is 50-200%, the return rate of the aerobic tank (2) is 50-200%, and the return rate of the anoxic tank (3) is 50-300%. By increasing the sludge concentration of the anaerobic tank (1), the aerobic tank (2) or the anoxic tank (3), the residence time required for each reaction tank is shortened, and by reducing the sludge concentration of the anaerobic tank (1), the aerobic tank (2) or the anoxic tank (3), the residence time of each reaction tank is increased.

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