An integrated AAO biological pond

Abstract

The present invention discloses an integrated AAO biological pool, comprising: an AAO biological pool unit and a sludge pump pool unit; wherein, the AAO biological pool unit is composed of a pre-anoxic zone, an anaerobic zone, an anoxic zone, an aerobic zone and a degassing zone which are connected in sequence; the sludge pump pool unit is embedded in the degassing zone of the AAO biological pool unit and is located at the end water outlet of the aerobic pool; the sludge pump pool unit is arranged with a common wall with the aerobic zone; the sludge pump in the sludge pump pool unit is connected to the pre-anoxic zone and the anoxic zone of the AAO biological pool unit respectively through channels arranged on the pool wall. This integrated AAO biological pool realizes the integration of the sludge pump unit in the AAO biological pool unit, and the sludge and sewage do not affect each other, and the sludge can be refluxed through the channels, reducing the problems of large land occupation of a separately arranged sludge pump pool, high energy consumption of pipeline reflux, inconvenient maintenance, high construction and operation costs, etc.

Description

Technical Field

[0001] The present invention relates to the field of sewage treatment, and in particular to an integrated AAO biological pool. Background Art

[0002] Currently, conventional sewage treatment plants mostly use the AAO main process which includes separately set AAO biological pool and sludge pump pool.

[0003] In existing AAO process wastewater treatment plants, the AAO biological tank and sludge pump tank are usually separated into two separate units. The sludge pump tank is located between the biological tank and the secondary sedimentation tank. The sludge inlet is drawn from the secondary sedimentation tank sludge discharge, and the sludge outlet is divided into two systems, consisting of two pump groups: an external return sludge pump and a residual sludge pump. The external return sludge is pumped to the biological tank inlet, and the return volume is usually 100% of the design capacity. The residual sludge is pumped to the sludge treatment system. The sludge pump tank can be combined with the secondary sedimentation tank water distribution well to form a circular or separate rectangular design. However, apart from the differences in pump tank type and water pump selection, the above two options are both adjacent to the biological tank and are set up as independent units. The return sludge is also transported to the biological tank inlet through the main sludge pipeline.

[0004] The existing AAO process engineering in which the AAO biological pool and the sludge pump pool are separately set up has at least the following disadvantages:

[0005] (1) An independent sludge pump pool requires a sludge pipeline to transport the sludge. The sludge needs to be transported over a long distance, which increases the hydraulic loss along the way and pushes up the head specification and energy consumption of the return pump. Taking a sewage treatment plant with a design scale of 50,000 tons / day as an example, the total length of the return sludge pipe from the pump pool to the water inlet end of the biological pool is 140 meters, and the design flow rate of the return sludge is 2083m 3 / h, according to the economic flow rate of 0.9m / s, a DN900 sludge conveying pipeline will be used, and the hydraulic loss along the pipeline and in some places will be about 0.4m, which will increase the power consumption by 85KWh / d. According to the average unit price of large industrial electricity in Beijing of 0.72 yuan / KWh, the annual electricity bill will be 22,300 yuan.

[0006] (2) The material and installation costs of the total return sludge pipeline will increase the project investment. For example, the material cost of a 140-meter-long DN900 welded steel pipe is RMB 140,400, and the installation cost of a 1.5-meter pipe-top covered pipeline is RMB 220,900, for a total of RMB 361,300. If ductile iron pipes are used, the corresponding material cost is RMB 236,000, and the installation cost of the pipeline is RMB 121,800, for a total of RMB 357,800.

[0007] (3) The sludge pump pool is designed separately, increasing the total floor area and the investment in supporting approaches and ladders. To minimize the total laying distance of the sludge pipeline, the sludge pump pool is usually located between the biological pool and the secondary sedimentation tank. The biological pool has a rectangular structure, and the secondary sedimentation tank is usually circular. Placing the pump pool in the middle will inevitably increase the distance between the biological pool and the secondary sedimentation tank for layout and construction. The distance between the above two scenarios is widened by at least 8 meters. Taking a sewage treatment plant with a design scale of 50,000 tons per day as an example, the total floor area of the pump pool itself and the space to the factory road is about 640 - 880 m 2 . At the same time, on a relatively large plot of land, a vehicle approach from the factory road to the pump pool needs to be considered to facilitate the transportation and installation of water pump equipment. The length of the approach is increased by about 40 meters, and the road width is at least 2 meters. The corresponding investment is 22,000 yuan. A ladder to the upper pool also needs to be set up in the pump pool, with an investment of 12,000 yuan. The total construction investment for the two items is 34,000 yuan. The above three items together involve an engineering construction investment of about 395,000 yuan, an annual operating cost of 22,300 yuan, and an occupied plot area of 640 - 880 m 2 . It should be specifically noted that the above investment does not include the foundation pit excavation, foundation construction, and exterior wall civil engineering costs for building the pump pool separately. Summary of the Invention

[0008] Based on the problems existing in the prior art, the purpose of the present invention is to provide an integrated AAO biological pool, which can solve the problems in the existing AAO process sewage treatment project, such as high energy consumption in long-distance sludge pipeline transportation, high cost of the total return sludge pipeline, large floor area of the sludge pump pool, and large investment, when the AAO biological pool and the sludge pump pool are set separately.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] An embodiment of the present invention provides an integrated AAO biological pool, including:

[0011] An AAO biological pool unit and a sludge pump pool unit; wherein,

[0012] The AAO biological pool unit is composed of a pre-anoxic zone, an anaerobic zone, an anoxic zone, an aerobic zone, and a degassing zone connected in sequence;

[0013] The sludge pump pool unit is embedded in the degassing zone of the AAO biological pool unit and is located at the end water outlet of the aerobic tank;

[0014] The sludge pump pool unit shares a wall with the biological area;

[0015] The sludge pumps in the sludge pump pool unit are connected to the pre-anoxic zone and the anoxic zone of the AAO biological pool unit respectively through channels provided on the pool wall.

[0016] As can be seen from the technical solution provided by the present invention above, the integrated AAO biological pool provided by the embodiments of the present invention has the following beneficial effects:

[0017] By embedding the sludge pump unit in the degassing area of the AAO biological pool unit and connecting the sludge pumps in the sludge pump pool unit to the pre-anoxic area and the anoxic area of the AAO biological pool unit through channels provided on the pool wall, the sludge pump unit is integrated into the AAO biological pool unit, and the sludge and sewage do not affect each other, and the sludge can be refluxed through the channels, reducing problems such as large land occupation of a separately arranged sludge pump pool, high energy consumption of pipeline reflux, inconvenient maintenance, and high construction and operation costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings without creative efforts based on these drawings.

[0019] Figure 1 It is a schematic plan view of the integrated AAO biological pool provided by the embodiments of the present invention;

[0020] Figure 2 It is a schematic plan view of the lower layer of the top plate of the local sludge pump pool unit of the integrated AAO biological pool provided by the embodiments of the present invention;

[0021] Figure 3 It is a schematic cross-sectional view of the sludge pump pool unit of the integrated AAO biological pool provided by the embodiments of the present invention Figure 1 ;

[0022] Figure 4 It is a schematic cross-sectional view of the sludge pump pool unit of the integrated AAO biological pool provided by the embodiments of the present invention Figure 2 ;

[0023] The components corresponding to the marks in the figure are: 100 - AAO biological pool unit; 200 - sludge pump pool unit; 1 - pre-anoxic area; 2 - anaerobic area; 3 - anoxic area; 4 - aerobic area; 5 - degassing area; 6 - internal reflux sludge pump pool; 7 - external reflux sludge pump pool; 8 - excess sludge pump pool; 9 - external reflux sludge channel; 10 - internal reflux sludge channel; 11 - internal reflux sludge pump; 12 - excess sludge pump; 13 - external reflux sludge pump; 14 - sludge valve well; 15 - valve well drain; 16 - inlet water distribution weir of the external reflux sludge pump pool; 17 - external reflux sludge pump guide wall; 18 - inlet sludge pipe from the secondary sedimentation tank; 19 - excess sludge discharge pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] Combined with the specific content of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention. The content not described in detail in the embodiments of the present invention belongs to the prior art well-known to those skilled in the art.

[0025] As Figure 1 shown, an integrated AAO biological pool provided by an embodiment of the present invention includes:

[0026] an AAO biological pool unit and a sludge pump pool unit; wherein,

[0027] the AAO biological pool unit is composed of a pre-anoxic zone, an anaerobic zone, an anoxic zone, an aerobic zone, and a degassing zone connected in sequence;

[0028] the sludge pump pool unit is embedded in the degassing zone of the AAO biological pool unit and is at the end water outlet of the aerobic pool;

[0029] the sludge pump pool unit is provided with a common wall with the aerobic zone of the AAO biological pool unit; preferably, the sludge pump pool unit is provided with a common wall with the internal reflux pump zone of the aerobic zone of the AAO biological pool unit;

[0030] the sludge pump in the sludge pump pool unit is connected to the pre-anoxic zone and the anoxic zone of the AAO biological pool unit respectively through a reflux sludge channel arranged on the pool wall.

[0031] See Figure 2 、 3 , in the integrated AAO biological pool described above, the sludge pump pool unit includes:

[0032] a surplus sludge pump pool, an external reflux sludge pump pool, an internal reflux sludge pool, a surplus sludge pump, an external reflux sludge pump, and an internal reflux sludge pump; wherein,

[0033] the surplus sludge pump pool and the external reflux sludge pump pool are arranged in parallel;

[0034] the internal reflux sludge pool is on one side of the parallel surplus sludge pump pool and the external reflux sludge pump pool, and the internal reflux sludge pool is on the side close to the water outlet end of the aerobic zone;

[0035] the surplus sludge pump is arranged in the surplus sludge pump pool and is connected to an external sludge storage tank through a sludge discharge pipe;

[0036] the external reflux sludge pump is arranged in the external reflux sludge pump pool;

[0037] The internal return sludge pump is installed in the internal return sludge tank;

[0038] The sludge pumps in the sludge pump pool unit are respectively connected to the pre-anoxic zone and the anoxic zone of the AAO biological pool unit through the return sludge channels arranged on the pool wall as follows:

[0039] The external return sludge pump is connected to the pre-anoxic zone of the AAO biological pool unit through the external return sludge channels arranged on the pool walls of the aerobic zone and the anoxic zone;

[0040] The internal return sludge pump is connected to the anoxic zone of the AAO biological pool unit through the internal return sludge channels arranged on the pool walls of the aerobic zone and the anoxic zone.

[0041] In the integrated AAO biological pool, the excess sludge pump adopts a submersible centrifugal pump;

[0042] Both the external return sludge pump and the internal return sludge pump adopt axial flow pumps.

[0043] In the integrated AAO biological pool, the external return sludge channel is suspended on the pool walls of the aerobic zone and the anoxic zone;

[0044] The internal return sludge channel is suspended on the pool walls of the aerobic zone and the anoxic zone;

[0045] The external return sludge channel and the internal return sludge channel are arranged side by side in the horizontal direction and have the same height and bottom in the vertical direction.

[0046] In the integrated AAO biological pool, the net width of the external return sludge channel is 0.8 m and the effective water depth is 0.8 m;

[0047] The net width of the internal return sludge channel is 0.8 m and the effective water depth is 0.8 m.

[0048] See Figure 4 , in the integrated AAO biological pool, the sludge valve well is arranged in the excess sludge pump pool;

[0049] The elevation of the well part in the sludge valve well is higher than the height of the highest liquid level in the excess sludge pump pool;

[0050] An accident drainage port is arranged on the bottom side of the sludge valve well, and the accident drainage port is communicated with the inside of the excess sludge pump pool. For example: the highest liquid level of the sludge pump pool is 1.70 m, the elevation of the bottom plate of the sludge valve well is 2.00 m, and the elevation difference between the two interfaces can meet the requirement that the accident drainage of the valve well can flow by gravity through the drainage port to the excess sludge pump pool, ensuring that the valve is not soaked by sewage. At the same time, there is no need to adopt pump drainage measures, which can save power consumption and reduce the maintenance of pump drainage measures.

[0051] The external return sludge pump pool is provided with a water inlet weir and a number of external return sludge pump guide walls;

[0052] The external return sludge pump is arranged between two adjacent external return sludge pump guide walls.

[0053] The pre-anoxic zone is composed of a first pre-anoxic pool and a second pre-anoxic pool that are symmetrically arranged, and the first pre-anoxic pool and the second pre-anoxic pool are rectangular pool bodies as a whole;

[0054] The anaerobic zone is composed of a first anaerobic tank and a second anaerobic tank arranged symmetrically, and both the first anaerobic tank and the second anaerobic tank adopt raceway-type channel tank bodies;

[0055] The anoxic zone is composed of a first anoxic pool and a second anoxic pool arranged symmetrically, and both the first anoxic pool and the second anoxic pool adopt racetrack-type channel pool bodies;

[0056] The aerobic pool is composed of a first aerobic pool and a second aerobic pool which are symmetrically arranged. Both the first aerobic pool and the second aerobic pool adopt a rotating gallery type pool body.

[0057] The embodiments of the present invention are described in further detail below.

[0058] like Figure 1 As shown, the embodiment of the present invention provides an integrated AAO biological pool, which is a two-phase system integrating sewage and sludge. While integrating, the AAO biological pool does not weaken the operation and treatment functions of each. The integrated AAO biological pool includes an AAO biological pool unit and a sludge pump pool unit. The sludge pump pool unit is embedded in the AAO biological pool unit and integrated with the AAO biological pool unit. The AAO biological pool unit consists of a pre-anoxic zone, an anaerobic zone, an anoxic zone, an aerobic zone and a degassing zone. Each reaction zone is symmetrically It is composed of two tanks, such as the pre-anoxic zone is composed of the first pre-anoxic tank and the second pre-anoxic tank arranged symmetrically; the anaerobic zone is composed of the first anaerobic tank and the second anaerobic tank arranged symmetrically; the anoxic zone is composed of the first anoxic tank and the second anoxic tank arranged symmetrically; the aerobic zone is composed of the first aerobic tank and the second aerobic tank arranged symmetrically; the degassing zone is composed of the first degassing zone and the second degassing zone arranged symmetrically; the pre-anoxic zone adopts a rectangular tank design, the anaerobic and anoxic zone tanks adopt runway-type channels, and the aerobic zone tanks adopt rotating corridors. Figure 1 .

[0059] The AAO biological pond unit with this structure has a stronger nitrogen and phosphorus removal function than a single AAO biological pond. The influent adopts multi-point influent, and during operation, the raw water carbon source can be flexibly switched and reasonably distributed according to the water quality. The setting of the pre-anoxic zone can reduce the phosphorus release function reduced by the dissolved oxygen carried by the external reflux sludge directly entering the anaerobic pond. The purpose of setting the terminal degassing zone is to reduce the dissolved oxygen in the internal reflux sludge so that it will not have a negative impact on the unit function environment when it flows back to the anoxic zone, playing a role in improving the removal rates of total nitrogen and total phosphorus indicators.

[0060] The sludge pump pond unit described is embedded in the degassing zone, between the first degassing zone and the second degassing zone in the degassing zone, and is integrated with the AAO biological pond unit. This sludge pump pond unit is placed at the water outlet end of the end corridor of the aerobic pond. On the premise of ensuring the water outlet weir length calculated by a reasonable weir head, the sludge pump pond unit and the internal reflux pump zone in the biological pond are arranged with a common wall, so that the surplus sludge pump pond included in the sludge pump pond unit and the external reflux sludge pump pond are arranged side by side, and the internal reflux sludge pump pond is arranged inside the two. By cleverly setting the layout of the external and internal reflux sludge pumps and the surplus sludge pump pond, the impact on the biochemical effluent can be avoided. The sludge inlet path of this sludge pump pond unit corresponds to the sludge discharge of the secondary sedimentation tank, and the sludge outlet path is the water inlet end of the AAO biological pond unit. The water outlet channels of the two aerobic ponds (i.e., the first aerobic pond and the second aerobic pond) are respectively arranged on both sides of the sludge pump pond unit, and the sewage and sludge systems are independent of each other and do not interfere with each other; the agitator in the degassing zone is arranged outside the internal reflux sludge pump pond, and the acting force of the agitator impeller obliquely acts on the sewage area to play a stirring function. The overall layout does not weaken the biochemical treatment function, meets the requirements of convenient operation and maintenance, regularizes the system, and makes the plane view simple and generous.

[0061] Such as Figure 2 、 Figure 3As shown in the figure, the sludge outlet pipe of the secondary sedimentation tank first enters the sludge inlet well, and after turning, it is distributed to the return sludge pump pool (inner and outer return sludge pump pools) and the excess sludge pump pool of the sludge pump pool unit through the sludge distribution channel; among them, the return sludge pump installed in the outer return sludge pump pool is an axial flow pump with low head and large flow. There is an inlet water distribution weir and an outer return sludge pump diversion wall in the outer return sludge pump pool, which can optimize and ensure the hydraulic flow pattern. At the same time, on the premise of ensuring that the effective volume meets the specification requirements of not less than the volume of the largest water pump for five minutes, the size of the sludge pump pool unit is minimized as much as possible to facilitate regular layout. After the sludge is lifted by the axial flow pump, it reaches the independent outlet weir at the vertical upper end. After the water drops through the independent outlet weir, it flows through the outer return sludge channel to the pre-anoxic zone. The tail end is controlled by a gate to open and the distribution ratio of the return sludge of the two pre-anoxic tanks (i.e., the first pre-anoxic tank and the second pre-anoxic tank). The return sludge is in a continuous opening condition, and a configuration of two out of three devices in use and one standby is adopted. The return sludge concentration is generally 7-8 g / l; there is one outer return sludge channel and two inner return sludge channels. The outer return sludge channel is located between the two inner return sludge channels, and they are arranged in parallel. The two channels have the same height and bottom vertically (see Figure 3 ).

[0062] The excess sludge pump installed in the excess sludge pump pool is a submersible centrifugal pump with high head and small flow. The daily lifting flow is the daily dry sludge production of the biochemical system at a water content of 99.2%, and it is in an intermittent opening condition, with a configuration of one out of two devices in use and one standby. After the excess sludge is lifted by the submersible centrifugal pump, it is transported to the subsequent sludge storage tank through the excess sludge discharge pipe and enters the sludge treatment system. The sludge valve well of the pipeline after the pump is embedded in the excess sludge pump pool by civil engineering (see Figure 4 ), which is convenient for maintaining the valve from the top of the pool, effectively utilizes the internal space of the excess sludge pump pool, and is no longer externally installed on the ground, avoiding the labor intensity of maintenance personnel frequently going up and down the pool body. In addition, the accident drainage of the sludge valve well no longer adopts the method of pumping to the sewage inspection well. By using the safety gap between the elevation of the sludge valve well and the highest liquid level in the excess sludge pump pool, the accident drainage port is reserved at the bottom to drain the water to the excess sludge pump pool by self-flow. This setting method neither requires setting up a secondary return sewage system for draining the sewage in the sludge valve well, nor can it save energy and improve the convenience of construction.

[0063] By arranging the sludge pump pool unit with the excess sludge pump pool and the outer return sludge pump pool arranged in parallel, and the inner return sludge pump pool arranged inside the two, and embedding it in the degassing zone at the end, making it integrated with the AAO biological pool unit, the three pump groups are designed to be close together, which is convenient for maintenance and repair. The integrated AAO biological pool has a more compact and reasonable floor area. The overall symmetric civil engineering layout is conducive to being adjacent to each functional area of the biochemical unit and regular layout.

[0064] The integrated AAO biology of the present invention has at least the following advantages:

[0065] (1) Embed the sludge pump pool unit inside the AAO biological pool unit to form an integrated AAO biological pool. And for the sludge reflux, change it to use the upper channel on the inner wall of the external biological pool. The net width of the channel is 0.8 m, the effective water depth is 0.8 m, the designed flow velocity is 0.9 m / S, the length of the channel is 50 m, and the total head loss due to friction and local resistance is 0.05 m. This saves 0.35 m of water loss compared with pipeline transportation, and the corresponding electricity consumption saved is 74 KWh / d. Calculated at the average unit price of 0.72 yuan / KWh for large industrial electricity in Beijing area, the annual electricity cost saved is 19,500 yuan.

[0066] (2) Cancel the material and installation costs of the corresponding total reflux sludge pipeline, and change it to a cantilever channel. The depth of the channel is 1.5 m, the net width is 0.8 m, and the pool roof also functions as a walkway slab. The estimated additional investment compared with the scheme without a reflux channel is no more than 70,000 yuan.

[0067] (3) After the sludge pump pool unit and the AAO biological pool unit are jointly constructed, there is no need for separate setting and no additional land occupation is required. Only consider the guarantee requirements for the effective volume of the biochemical pool. Since joint construction requires an increase in the pool volume to a certain extent, the corresponding single - body floor area expands by 106 - 150 m 2 . The original supporting approach roads and ladders added for separate setting can be shared with the biological pool monomer, and the investment in this part of the facilities is cancelled accordingly.

[0068] In summary, the integrated AAO biological pool of the present invention saves about 325,000 yuan in project construction investment compared with the conventional scheme (here the investment does not include the foundation pit excavation, foundation construction and external wall civil engineering costs for separately constructing the pump pool. If included, the optimization range is larger), saves 19,500 yuan in annual operation cost, and can reduce the occupied land area by 534 - 730 m 2 . Generally, the operation period of sewage treatment projects is not less than 30 years. Calculated over the whole cycle, a total cost of 910,000 yuan can be saved. At the same time, the saved land can be transferred for other monomers to use, making the general layout more compact and regular, greatly saving the construction land index for similar projects. In the current environment of increasingly tight land use in China, it effectively reduces the area of project declaration and approval.

[0069] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An integrated AAO biological pool, characterized in that: Including: AAO biological pond unit and sludge pump pond unit; wherein, The AAO biological pond unit is composed of a pre-anoxic zone, an anaerobic zone, an anoxic zone, an aerobic zone, and a degassing zone connected in sequence; The sludge pump pond unit is arranged inside the AAO biological pond unit and is embedded in the degassing zone, at the end water outlet of the aerobic zone; The sludge pump pond unit is arranged with a common wall with the aerobic zone of the AAO biological pond unit; The sludge pumps in the sludge pump pond unit are connected to the pre-anoxic zone and the anoxic zone of the AAO biological pond unit respectively through the return sludge channels arranged on the pool wall; The sludge pump pond unit includes: a surplus sludge pump pond, an external return sludge pump pond, an internal return sludge pond, a surplus sludge pump, an external return sludge pump, and an internal return sludge pump; wherein, The surplus sludge pump pond and the external return sludge pump pond are arranged in parallel; The internal return sludge pond is on one side of the parallel surplus sludge pump pond and external return sludge pump pond, and the internal return sludge pond is on the side close to the water outlet of the aerobic zone; The surplus sludge pump is arranged in the surplus sludge pump pond and is connected to an external sludge storage pond through a sludge discharge pipe; The external return sludge pump is arranged in the external return sludge pump pond; The internal return sludge pump is arranged in the internal return sludge pond; The sludge pumps in the sludge pump pond unit are connected to the pre-anoxic zone and the anoxic zone of the AAO biological pond unit respectively through the return sludge channels arranged on the pool wall as follows: The external return sludge pump is connected to the pre-anoxic zone of the AAO biological pond unit through the external return sludge channel arranged on the pool walls of the aerobic zone and the anoxic zone; The internal return sludge pump is connected to the anoxic zone of the AAO biological pond unit through the internal return sludge channel arranged on the pool walls of the aerobic zone and the anoxic zone; The external return sludge channel is hung on the pool walls of the aerobic zone and the anoxic zone; The internal return sludge channel is hung on the pool walls of the aerobic zone and the anoxic zone; The external return sludge channel and the internal return sludge channel are arranged in parallel in the horizontal direction and have the same height and bottom in the vertical direction; The surplus sludge pump adopts a submersible centrifugal pump; Both the external return sludge pump and the internal return sludge pump adopt axial flow pumps.

2. The integrated AAO biological pond according to claim 1, characterized in that, The net width of the external return sludge channel is 0.8m, and the effective water depth is 0.8m; The net width of the internal return sludge channel is 0.8m, and the effective water depth is 0.8m.

3. The integrated AAO biological pond according to claim 1 or 2, characterized in that, A sludge valve well is arranged in the surplus sludge pump pond; The elevation of the well part in the sludge valve well is higher than the height of the highest liquid level in the surplus sludge pump pond; An accident drainage port is arranged on the bottom side of the sludge valve well, and the accident drainage port is communicated with the inside of the surplus sludge pump pond.

4. The integrated AAO biological pond according to claim 1, characterized in that An inlet water distribution weir and several external return sludge pump diversion walls are arranged in the external return sludge pump pond; The external return sludge pump is arranged between two adjacent external return sludge pump diversion walls.

5. The integrated AAO biological pond according to claim 1, characterized in that, The pre-anoxic zone is composed of a symmetrically arranged first pre-anoxic pond and a second pre-anoxic pond, and the first pre-anoxic pond and the second pre-anoxic pond are an overall rectangular pool body; The anaerobic zone is composed of a symmetrically arranged first anaerobic pond and a second anaerobic pond, and both the first anaerobic pond and the second anaerobic pond adopt a runway-shaped channel pool body; The anoxic zone is composed of a first anoxic pool and a second anoxic pool arranged symmetrically, and both the first anoxic pool and the second anoxic pool adopt racetrack-type channel pool bodies; The aerobic zone is composed of a first aerobic tank and a second aerobic tank which are symmetrically arranged, and both the first aerobic tank and the second aerobic tank adopt a rotary corridor type tank body 。

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