A pumpless self-operation method and operation system for an automatically lifting two-stage A / O reaction pool

Abstract

The invention discloses a pumpless self-operation method and operation system of an automatically lifting two-stage A / O reaction tank. The self-operation system comprises an anoxic reaction tank with a height-to-diameter ratio of not less than 3 and an aerobic reaction tank with a height-to-diameter ratio of not less than 4. The anoxic reaction tank is fixed on upper and lower telescopic frames, and the bottom of the anoxic reaction tank is higher than the aerobic reaction tank in height from the ground. An impeller with a height of 1 / 2 of the water depth in the tank is installed in the anoxic reaction tank. The bottom of the anoxic zone is connected to the aerobic zone through a lower connecting pipe inclined downward and the upper part is connected to the aerobic zone through a horizontal upper connecting pipe. An aeration device is arranged at the bottom of the aerobic reaction tank. Sewage is pumped from an inlet tank to the center of the impeller through a lifting pump and then enters the tank. The impeller stirs slowly, and muddy water flows into the aerobic zone through the lower connecting pipe from the bottom of the anoxic zone, rises under the action of aeration of the aeration device, and flows into the anoxic zone through the upper connecting pipe to realize pumpless self-flow circulation. The invention realizes pumpless self-flow circulation, can adjust the water depth of the anoxic reaction tank, and change the hydraulic retention time of the anoxic section.

Description

Technical Field

[0001] The present invention relates to the field of biological sewage treatment technology and is applicable to efficient denitrification of sewage and restoration of sludge performance. The present invention specifically discloses a pumpless self-operation method and operation system for an automatically lifting two-stage A / O reaction tank. Background Art

[0002] Traditional AO (anoxic-aerobic) biological denitrification processes require an internal recirculation pump to recirculate sludge. Improving denitrification efficiency requires increasing the internal recirculation ratio, which increases operating costs. Furthermore, the internal recirculation fluid, originating from the aeration tank, contains a large amount of dissolved oxygen (DO), making it difficult to maintain an ideal anoxic state throughout the anoxic A section, impacting denitrification effectiveness and system stability.

[0003] The inventors achieved the purpose of alternating AO self-circulation by changing the shape of the two reaction tanks and the power generated internally, thereby eliminating the internal reflux pump. At the same time, the water depth can be changed by raising the anoxic reaction tank, thereby changing the hydraulic retention time of the anoxic section, thereby adapting to changes in different water qualities and saving operating costs. Summary of the Invention

[0004] The present invention provides a pumpless self-operation method and operating system for an automatically rising and falling two-stage A / O reaction tank, which aims to solve the technical problems in the traditional AO (anoxic-aerobic) biological denitrification process, in which an internal reflux pump is required to reflux sludge, making it difficult to maintain an ideal anoxic state in the entire anoxic A section, affecting the denitrification effect and system stability, and the inability to change the hydraulic retention time of the anoxic A section to adapt to different water quality changes.

[0005] The technical solutions of the present invention are as follows:

[0006] A pumpless self-operation method for an automatically lifting two-stage A / O reaction pool, characterized by comprising:

[0007] 1) Setting up a self-operating system: comprising two cylindrical reaction tanks, an anoxic reaction tank 7 and an aerobic reaction tank 8, wherein the anoxic reaction tank has a height-to-diameter ratio of not less than 3, and the aerobic reaction tank has a height-to-diameter ratio of not less than 4; the water area within the anoxic reaction tank 7 is an anoxic zone 71, and the water area within the aerobic reaction tank 8 is an aerobic zone 81; the bottom of the aerobic reaction tank 8 is supported on the ground; the anoxic reaction tank 7 is fixed to upper and lower telescopic frames 3 supported on the ground, and the bottom of the anoxic reaction tank 7 is higher above the ground than the aerobic reaction tank 8;

[0008] An impeller 2 is horizontally installed in the anoxic reaction tank, and the installation height of the impeller 2 from the bottom of the tank is 1 / 2 of the water depth in the tank; the impeller has hyperbolic blades and is driven to rotate by the mixer 1; a vertical upward water inlet pipe is set at the center of the impeller 2, and the water inlet pipe is connected to the water inlet tank through a water delivery pipe and a lifting pump outside the tank;

[0009] The bottom of the anoxic reaction tank is connected to the aerobic reaction tank obliquely downward through a lower connecting pipe 9, and an aeration device 5 is provided at the bottom of the aerobic reaction tank; the upper part of the aerobic reaction tank is connected to the anoxic reaction tank through a horizontally arranged upper connecting pipe 91 and connects the anoxic zone and the aerobic zone, and the upper connecting pipe is located above the impeller;

[0010] 2) Operation of the anoxic reaction tank: After the sewage is pumped from the water inlet tank to the top of the anoxic reaction tank by the lifting pump, it is transported to the center of the impeller 2 installed in the anoxic reaction tank 7 through a plumb vertical water inlet pipe to enter the tank; the outer diameter of the impeller blades is controlled to be 1 / 2 to 2 / 3 of the diameter of the anoxic zone 71, and the mixer 1 is driven to rotate to slowly stir the muddy water in the tank. The stirring speed is controlled within the range of 60 to 70 r / min, so as to achieve a large-area uniform water flow with less power; the muddy water in the anoxic zone 71 above the impeller is fully stirred, and partial anoxic denitrification occurs. The slow stirring reduces the impact of the turbulence generated by the impeller stirring on the water flow below the impeller in the anoxic zone 71; because the mixer is far away from the bottom of the anoxic zone 71, the stirring force on the lower part of the anoxic zone is small, forming a soft water flow;

[0011] 3) Aerobic reaction tank operation: Under the top-down pressure exerted by the internal and external water inflow of the anoxic reaction tank 7, the muddy water flows into the aerobic reaction tank through the bottom of the anoxic zone 71 through the lower connecting pipe 9 arranged obliquely downward and connected to the lower part of the aerobic reaction tank wall. At the same time, the muddy water in the aerobic zone 81 of the aerobic reaction tank rises under the action of aeration of the aeration device 5 at the bottom of the tank, and flows into the anoxic zone through the upper connecting pipe 91 horizontally connected to the upper part of the tank wall to realize pump-free gravity circulation;

[0012] The anoxic reaction tank and the aerobic reaction tank are operated back and forth in this way to realize pump-free gravity circulation.

[0013] The method for pumpless self-operation of an automatically lifting two-stage A / O reaction tank, wherein, in the step 1, the height of the bottom of the anoxic reaction tank 7 from the ground is adjusted by telescoping the upper and lower telescopic frames, and the height of the anoxic zone 71 from the ground and the water depth of the anoxic zone are simultaneously adjusted; the higher the height of the anoxic zone 71 from the ground, the shallower the water depth of the anoxic zone 71 and the smaller the water volume; under the premise that the water inlet flow rate remains unchanged, the smaller the water volume, the shorter the hydraulic retention time of the anoxic tank, so as to control the anoxic / aerobic hydraulic retention time ratio.

[0014] The described automatic lifting two-stage A / O reaction tank pumpless self-operation method, wherein a circular hole with a diameter of 0.2m is opened in the center of the bottom of the anoxic reaction tank, and a circular hole with a diameter of 0.2m is also opened on the wall of the aerobic reaction tank 8 at a distance of 1.5m from the bottom of the aerobic reaction tank and is lower than the bottom of the anoxic reaction tank. The two circular holes are connected to the lower connecting pipe 9 to receive the muddy water after the reaction in the anoxic reaction tank 7.

[0015] The described method for pumpless self-operation of an automatically rising and falling two-stage A / O reaction tank, wherein the upper connecting pipe 91 is installed below the liquid level 1.0m from the top liquid level of the aerobic reaction tank and is located above the impeller, and is connected to the side wall openings of the anoxic reaction tank 7 and the aerobic reaction tank 8 and maintained in a horizontal arrangement, and the diameter of the side wall openings is 0.2m; a butterfly valve 6 is provided on the upper connecting pipe to control the water flow; a plurality of openings are provided at intervals from top to bottom on the side wall of the anoxic reaction tank 7 and valves are provided respectively to adjust the corresponding connection positions with the upper connecting pipe; a sludge return port 11 is provided on the pool wall above the impeller below the liquid level of the anoxic reaction tank.

[0016] The method for pumpless self-operation of an automatically lifting two-stage A / O reaction tank further includes: 4) changing the hydraulic retention time of the system by adjusting the water flow rate of the lifting pump or the water depth of the anoxic reaction tank 7; the hydraulic retention time is equal to the ratio of the reactor volume to the water flow rate; and adjusting the internal reflux flow rate by adjusting the switch of the butterfly valve 6.

[0017] The present invention provides an automatically lifting two-stage A / O reaction tank pumpless self-operating system, characterized in that it comprises two cylindrical reaction tanks, an anoxic reaction tank 7 and an aerobic reaction tank 8, wherein the height-to-diameter ratio of the anoxic reaction tank is not less than 3, and the height-to-diameter ratio of the aerobic reaction tank is not less than 4; the water area in the anoxic reaction tank 7 is an anoxic zone 71, and the water area in the aerobic reaction tank 8 is an aerobic zone 81; the bottom of the aerobic reaction tank 8 is supported on the ground; the anoxic reaction tank 7 is fixed on upper and lower telescopic frames 3 supported on the ground, and the bottom of the anoxic reaction tank 7 is higher than that of the aerobic reaction tank 8;

[0018] An impeller 2 is horizontally installed in the anoxic reaction tank, and the installation height of the impeller 2 from the bottom of the tank is 1 / 2 of the water depth in the tank; the impeller has hyperbolic blades and is driven to rotate by the mixer 1; a vertical upward water inlet pipe is set at the center of the impeller 2, and the water inlet pipe is connected to the water inlet tank through a water delivery pipe and a lifting pump outside the tank;

[0019] The bottom of the anoxic reaction tank is connected to the aerobic reaction tank obliquely downward through a lower connecting pipe 9, and an aeration device 5 is provided at the bottom of the aerobic reaction tank; the upper part of the aerobic reaction tank is connected to the anoxic reaction tank through a horizontally arranged upper connecting pipe 91 and connects the anoxic zone and the aerobic zone, and the upper connecting pipe is located above the impeller.

[0020] The operating system is characterized in that a circular hole with a diameter of 0.2m is provided at the bottom center of the anoxic reaction tank and at a distance of 1.5m from the bottom of the aerobic reaction tank 8 to connect to the lower connecting pipe 9; the upper connecting pipe 91 is installed below the liquid surface of the aerobic reaction tank at a distance of 1.0m and above the impeller, and is connected to the side wall openings of the anoxic reaction tank 7 and the aerobic reaction tank 8 and maintained in a horizontal arrangement, and the diameter of the side wall opening is 0.2m; a plurality of side wall openings are arranged at intervals from top to bottom on the side wall of the anoxic reaction tank 7 and are respectively provided with valves to adjust the corresponding connection positions with the upper connecting pipe; a sludge return port 11 is provided on the wall of the anoxic reaction tank above the impeller below the liquid surface; a butterfly valve 6 is provided on the upper connecting pipe to control the water flow; and the mixer is a hyperbolic mixer.

[0021] As mentioned above, the inventors can achieve the purpose of self-circulation of AO alternation by setting the shape and height-to-diameter ratio of the two reaction pools and the power generated internally, thereby eliminating the internal reflux pump. At the same time, the reaction pool with a larger height-to-diameter ratio can achieve laminar flow in section A, and the lower part maintains a better anoxic state to fully utilize the carbon source of the incoming water. At the same time, in actual applications, the anoxic reaction pool can be raised by the upper and lower telescopic frames to change the water depth, thereby changing the hydraulic retention time of the anoxic section, thereby adapting to changes in different water qualities and saving operating costs.

[0022] The present invention also controls the return flow of nitrification liquid by adjusting the valve opening and closing. It also effectively promotes long-distance sludge circulation within the tank, enabling sludge movement through different substrate concentrations and DO conditions. Stirring and aeration provide sufficient shear force, promoting the production of extracellular polymers in flocculent sludge, improving sludge stability, and enhancing denitrification efficiency. This effectively saves floor space and reduces costs.

[0023] The present invention assembles two tank bodies with a large aspect ratio in series through a connecting pipe, and realizes anoxic / aerobic alternating cycles according to the shape of the tank body and the stirring and aeration forces formed inside the system to achieve denitrification. The entire system includes a water inlet system, a drainage system, aeration equipment, stirring equipment, and sludge return equipment. Sewage enters from the top of the anoxic zone, and a hyperbolic mixer is set to perform anoxic stirring. The muddy water in the anoxic zone flows into the aerobic zone through the lower connecting pipe under the pressure of continuous water inflow. At the same time, the muddy water in the aerobic zone returns to the anoxic zone through the upper connecting pipe under the lift of aeration, completing the gravity circulation. At the same time, the anoxic reaction tank can be raised to change the water depth, thereby changing the hydraulic retention time of the anoxic section to adapt to the changes in water quality in actual applications.

[0024] Beneficial effects of the present invention

[0025] (1) No reflux pump is used, achieving gravity circulation; (2) By adjusting the water depth of the anoxic reaction tank, the hydraulic retention time of the anoxic section is changed to adapt to different water quality changes, thereby reducing investment and operating costs. (3) Laminar flow is achieved in the anoxic zone with a large aspect ratio, ensuring a good anoxic environment and enhancing denitrification. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention,

[0027] Figure 2 yes Figure 1 The left side schematic diagram of

[0028] Figure 3 yes Figure 1 A top-down diagram of

[0029] Figure 4 This is a schematic diagram of the structure of an embodiment of an elevated anoxic reaction pool according to the present invention.

[0030] Figure 5 yes Figure 4 The left side schematic diagram of

[0031] Figure 6 yes Figure 4 Schematic top view of .

[0032] Description of the accompanying figures:

[0033] 1-Hyperboloid mixer controller; 2-Impeller; 3-Telescopic frame; 4-Sampling port; 5-Aeration plate; 6-Butterfly valve; 7-Anoxic reaction tank, anoxic zone 71; 8-Aerobic reaction tank, aerobic zone 81; 9-Lower connecting pipe, upper connecting pipe 91; 10-Water inlet; 11-Return sludge outlet; 12-Water outlet; 13-Internal return port. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] See also Figure 1-3 As shown, the present invention provides a pumpless self-operation method for an automatically lifting two-stage A / O reaction pool, comprising:

[0036] 1) Setting up a self-operating system: comprising two cylindrical reaction tanks, an anoxic reaction tank 7 and an aerobic reaction tank 8, wherein the anoxic reaction tank has a height-to-diameter ratio of not less than 3, and the aerobic reaction tank has a height-to-diameter ratio of not less than 4; the water area within the anoxic reaction tank 7 is an anoxic zone 71, and the water area within the aerobic reaction tank 8 is an aerobic zone 81; the bottom of the aerobic reaction tank 8 is supported on the ground; the anoxic reaction tank 7 is fixed to upper and lower telescopic frames 3 supported on the ground, and the bottom of the anoxic reaction tank 7 is higher above the ground than the aerobic reaction tank 8;

[0037] An impeller 2 is horizontally installed in the anoxic reaction tank, and the installation height of the impeller 2 from the bottom of the tank is 1 / 2 of the water depth in the tank; the impeller has hyperbolic blades and is driven to rotate by the mixer 1; a vertical upward water inlet pipe is set at the center of the impeller 2, and the water inlet pipe is connected to the water inlet tank through a water delivery pipe and a lifting pump outside the tank;

[0038] The bottom of the anoxic reaction tank is connected to the aerobic reaction tank obliquely downward through a lower connecting pipe 9, and an aeration plate 5 is provided at the bottom of the aerobic reaction tank; the upper part of the aerobic reaction tank is connected to the anoxic reaction tank through a horizontal upper connecting pipe 91 and connects the anoxic zone and the aerobic zone, and the upper connecting pipe is located above the impeller;

[0039] 2) Operation of the anoxic reaction tank: After the sewage is pumped from the water inlet tank to the top of the anoxic reaction tank by the lifting pump, it is transported to the center of the impeller 2 installed in the anoxic reaction tank 7 through a plumb vertical water inlet pipe to enter the tank; the outer diameter of the impeller blades is controlled to be 1 / 2 to 2 / 3 of the diameter of the anoxic zone 71, and the mixer 1 is driven to rotate to slowly stir the muddy water in the tank. The stirring speed is controlled within the range of 60 to 70 r / min, so as to achieve a large-area uniform water flow with less power; the muddy water in the anoxic zone 71 above the impeller is fully stirred, and partial anoxic denitrification occurs. The slow stirring reduces the impact of the turbulence generated by the impeller stirring on the water flow below the impeller in the anoxic zone 71; because the mixer is far away from the bottom of the anoxic zone 71, the stirring force on the lower part of the anoxic zone is small, forming a soft water flow;

[0040] 3) Aerobic reaction tank operation: Under the top-down pressure exerted by the internal and external water inflow of the anoxic reaction tank 7, the muddy water flows into the aerobic reaction tank through the bottom of the anoxic zone 71 through the lower connecting pipe 9 arranged obliquely downward and connected to the lower part of the aerobic reaction tank wall. At the same time, the muddy water in the aerobic zone 81 of the aerobic reaction tank rises under the action of aeration of the aeration disk 5 at the bottom of the tank, and flows into the anoxic zone through the upper connecting pipe 91 horizontally connected to the upper part of the tank wall and the anoxic reaction tank, realizing pump-free gravity circulation;

[0041] The anoxic reaction tank and the aerobic reaction tank are operated back and forth in this way to realize pump-free gravity circulation.

[0042] The method for pumpless self-operation of an automatically lifting two-stage A / O reaction tank, wherein, in the step 1, the height of the bottom of the anoxic reaction tank 7 from the ground is adjusted by telescoping the upper and lower telescopic frames, and the height of the anoxic zone 71 from the ground and the water depth of the anoxic zone are simultaneously adjusted; the higher the height of the anoxic zone 71 from the ground, the shallower the water depth of the anoxic zone 71 and the smaller the water volume; under the premise that the water inlet flow rate remains unchanged, the smaller the volume, the shorter the hydraulic retention time of the anoxic tank, so as to control the anoxic / aerobic hydraulic retention time ratio.

[0043] The described automatic lifting two-stage A / O reaction tank pumpless self-operation method, wherein a circular hole with a diameter of 0.2m is opened in the center of the bottom of the anoxic reaction tank, and a circular hole with a diameter of 0.2m is also opened on the wall of the aerobic reaction tank 8 at a distance of 1.5m from the bottom of the aerobic reaction tank and is lower than the bottom of the anoxic reaction tank. The two circular holes are connected to the lower connecting pipe 9 to receive the muddy water after the reaction in the anoxic reaction tank 7.

[0044] The described method for pumpless self-operation of an automatically rising and falling two-stage A / O reaction tank, wherein the upper connecting pipe 91 is installed below the liquid level 1.0m from the top liquid level of the aerobic reaction tank and is located above the impeller, and is connected to the side wall openings of the anoxic reaction tank 7 and the aerobic reaction tank 8 and maintained in a horizontal arrangement, and the diameter of the side wall openings is 0.2m; a butterfly valve 6 is provided on the upper connecting pipe to control the water flow; a plurality of openings are provided at intervals from top to bottom on the side wall of the anoxic reaction tank 7 and valves are provided respectively to adjust the corresponding connection positions with the upper connecting pipe; a sludge return port 11 is provided on the pool wall above the impeller below the liquid level of the anoxic reaction tank.

[0045] The method for pumpless self-operation of an automatically lifting two-stage A / O reaction tank further includes: 4) changing the hydraulic retention time of the system by adjusting the water flow rate of the lifting pump or the water depth of the anoxic reaction tank 7; the hydraulic retention time is equal to the ratio of the reactor volume to the water flow rate; and adjusting the internal reflux flow rate by adjusting the switch of the butterfly valve 6.

[0046] See also Figure 1-6 As shown, the present invention provides an automatically lifting two-stage A / O reaction tank pumpless self-operating system, which includes two cylindrical reaction tanks, an anoxic reaction tank 7 and an aerobic reaction tank 8. The anoxic reaction tank has a height-to-diameter ratio of not less than 3, and the aerobic reaction tank has a height-to-diameter ratio of not less than 4. The water area in the anoxic reaction tank 7 is an anoxic zone 71, and the water area in the aerobic reaction tank 8 is an aerobic zone 81. The bottom of the aerobic reaction tank 8 is supported on the ground. The anoxic reaction tank 7 is fixed on upper and lower telescopic frames 3 supported on the ground, and the bottom of the anoxic reaction tank is higher than that of the aerobic reaction tank 8.

[0047] An impeller 2 is horizontally installed in the anoxic reaction tank, and the installation height of the impeller 2 from the bottom of the tank is 1 / 2 of the water depth in the tank; the impeller has hyperbolic blades and is driven to rotate by the mixer 1; a vertical upward water inlet pipe is set at the center of the impeller 2, and the water inlet pipe is connected to the water inlet tank through a water delivery pipe and a lifting pump outside the tank;

[0048] The bottom of the anoxic reaction tank is connected to the aerobic reaction tank obliquely downward through a lower connecting pipe 9, and an aeration plate 5 is provided at the bottom of the aerobic reaction tank. The upper part of the aerobic reaction tank is connected to the anoxic reaction tank through a horizontally arranged upper connecting pipe 91 and connects the anoxic zone and the aerobic zone. The upper connecting pipe is located above the impeller.

[0049] The operating system is characterized in that a circular hole with a diameter of 0.2m is provided at the bottom center of the anoxic reaction tank and at a distance of 1.5m from the bottom of the aerobic reaction tank 8 to connect to the lower connecting pipe 9; the upper connecting pipe 91 is installed below the liquid level of the aerobic reaction tank 1.0m and above the impeller, and is connected to the side wall openings of the anoxic reaction tank 7 and the aerobic reaction tank 8 and maintained in a horizontal arrangement, and the side wall opening has a diameter of 0.2m; a plurality of side wall openings are arranged at intervals from top to bottom on the side wall of the anoxic reaction tank 7 and are respectively provided with valves to adjust (when adjusting the height of the anoxic reaction tank) the corresponding connection position with the upper connecting pipe; a sludge return port 11 is provided on the pool wall above the impeller below the liquid level of the anoxic reaction tank; a butterfly valve 6 is provided on the upper connecting pipe to control the water flow; and the mixer is a hyperbolic mixer.

[0050] The reason why the upper connecting pipe of the present invention is installed at a certain depth below the water surface is that it can ensure sufficient reflux in the aerobic zone and that the dissolved oxygen can be fully consumed from the top to the bottom of the anoxic zone. In order to ensure laminar flow in the anoxic zone and sufficient aeration in the aerobic zone, the height-to-diameter ratio of the anoxic reaction tank is not less than 3, and the height-to-diameter ratio of the aerobic reaction tank is not less than 4. The internal reflux flow rate can be adjusted by adjusting the butterfly valve 6 switch to change the denitrification efficiency. The mixer is a hyperbolic mixer. This is due to the unique impeller structure design of the hyperbolic mixer, which can maximize the combination of fluid characteristics and mechanical movement. The curve stirred by the hyperbolic impeller is a curved body formed by rotating in the vertical direction; in order to cater to the flow of water, the water is designed to enter from the center of the impeller. On the one hand, this reduces the turbulence of the water inlet, and on the other hand, it ensures that the pressure of the liquid on the impeller surface is uniform, so to a large extent, a large area of ​​soft water flow can be obtained with less power.

[0051] Example

[0052] The following examples are provided merely to illustrate the present invention and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other variations or modifications may be made based on the following description. Such obvious variations or modifications arising from the spirit of the present invention are still within the scope of protection of the present invention.

[0053] refer to Figure 1 、 4 As shown, the present invention is an automatic lifting two-stage A / O reaction tank pumpless self-operating system, which specifically includes an anoxic reaction tank, an aerobic reaction tank, a water inlet unit, a stirring device, an aeration device, a water outlet unit, and a reflux unit. The specific working steps are as follows:

[0054] The anoxic reaction tank 7 has a height of 6 m, a diameter of 2 m, and a height-to-diameter ratio of 3; the aerobic reaction tank 8 has a height of 8 m, a diameter of 2 m, and a height-to-diameter ratio of 4.

[0055] The sewage enters from the impeller 2 at the top of the anoxic zone 71, and the hyperbolic blades provide thrust for the muddy water to be stirred. The mixer 1 is a hyperbolic mixer, and water enters from the center of the mixer impeller 2, which reduces the turbulence of the water inlet and makes the mixing uniform, thereby obtaining a soft water flow. During the actual operation, the speed can also be appropriately lowered to ensure that the water flow in the anoxic zone 71 will not be affected by the turbulence generated by the stirring and affect the smooth flow into the aerobic zone.

[0056] The installation position of the stirring impeller 2 is different from that of conventional water treatment processes. It is set at the upper part of the anoxic zone, 1 / 2 of the depth of the pool water from the bottom of the pool. This is to avoid the formation of negative pressure in the water flow at the bottom when the rotation speed is too fast and the water inlet flow rate is too fast, and the water flow is affected when it flows into the aerobic zone through the lower connecting pipe with a smaller opening. At the same time, it is also to make the lower area obtain a soft water flow and ensure a good anoxic environment.

[0057] At the same time, since the water flow at the bottom of the anoxic zone 71 is gentle and the stirring force is small, in order to avoid dead corners in the anoxic zone 71, a lower connecting pipe 9 for the anoxic zone 71 to flow into the aerobic zone 81 is set at the bottom of the anoxic zone 71. A circular hole with a diameter of 0.2m is opened in the center of the bottom of the anoxic reaction tank for installing the lower connecting pipe 9 and connecting it to the aerobic reaction tank 8. After a period of anoxic stirring, the muddy water flows out from the bottom of the anoxic zone 71 to the aerobic zone 81. A 0.2m circular hole is also opened at the lower part of the aerobic reaction tank 8 at a distance of 1.5m from the bottom of the tank to receive the muddy water after the reaction in the anoxic reaction tank 7.

[0058] The telescopic frame 3 fixed to the wall of the anoxic zone 71 adjusts the height of the anoxic zone 71 from the ground, thereby adjusting the actual water depth of the anoxic zone and thus controlling the anoxic zone volume (i.e., the volume of water in the anoxic zone below the outlet water surface). This allows for different anoxic / aerobic hydraulic retention time ratios and adaptability to varying water qualities. To ensure that the relative position of the return sludge outlet 11 and the upper connecting pipe 9 remains unchanged, the opening should be located at the same distance from the water surface.

[0059] Figure 1 、 4 The water height of the aerobic zone is 8 meters. Figure 1 The bottom of the middle anoxic zone 71 is 2 meters above the ground, and the water depth of the anoxic zone 71 is 6 meters. Figure 4 The bottom of the middle anoxic zone 71 is 3 meters above the ground. Figure 1 The bottom of the hypoxic zone in the pool is 1 meter higher from the ground. Therefore, the water depth in the hypoxic zone is 5 meters. Figure 1 The water depth of the anoxic zone becomes shallower and the volume of the anoxic zone becomes smaller.

[0060] The calculation method for adjusting the volume of the anoxic zone 71 corresponding to the height of the anoxic zone from the ground and the ratio of the hydraulic retention time of the anoxic zone to the aerobic zone is as follows:

[0061] ① Volume of hypoxic zone V1=πR1 2 ×h1

[0062] Where V1 is the volume of the hypoxic zone, unit is m 3

[0063] R1 is the radius of the hypoxic zone, in m

[0064] h1 is the water height (depth) of the anoxic zone, in meters

[0065] ② Aerobic zone volume V2=πR2 2 ×h2

[0066] Where V2 is the volume of the aerobic zone, unit is m 3

[0067] R2 is the radius of the aerobic zone, in m

[0068] h2 is the water height in the aerobic zone, in m

[0069] ③ Hydraulic retention time in anoxic zone HRT1=V1 / Q

[0070] Where HRT1 is the hydraulic retention time in the anoxic zone

[0071] Q is the system water flow

[0072] V1 is the volume of the hypoxic zone

[0073] ④ Hydraulic retention time in aerobic zone HRT2=V2 / Q

[0074] Where HRT2 is the hydraulic retention time in the aerobic zone

[0075] Q is the system water flow

[0076] V2 is the volume of the aerobic zone

[0077] ⑤ Therefore, the hydraulic retention time ratio is the volume ratio

[0078] That is, HRT1 / HRT2=V1 / V2

[0079] In actual operation, the water flow rate and hydraulic retention time are determined based on actual needs. Therefore, this invention only provides a method for adjusting the volume of the anoxic zone and the ratio of the hydraulic retention time of the anoxic zone to the aerobic zone by adjusting the height of the anoxic zone from the ground. The calculation table is as follows:

[0080]

[0081] The embodiment of adjusting the height of the anoxic zone to 3.0m from the ground by the telescopic frame is shown in the attached figure. Figure 4As shown in the figure: at this time, the height of the anoxic zone from the ground is 3.0m, the water surface height remains unchanged, and the opening position of the upper side wall of the anoxic zone is still 1.0m away from the water surface to ensure that the upper connecting pipe 91 is connected horizontally. At this time, the height of the anoxic zone is 5.0m, so the volume of the anoxic zone is reduced to 15m 3 At this time, the hydraulic retention time ratio of the anoxic zone / aerobic zone is 0.62.

[0082] In the denitrification process, the role of the anoxic zone is denitrification, and the role of the aerobic zone is to carbonize organic matter and nitrify nitrogen. Therefore, the volume of the two pools is particularly important for the removal rate of nitrogen and organic matter. Under actual water inlet fluctuations, the denitrification efficiency can be effectively increased by adjusting the volume of the anoxic zone to adapt to changes in water quality.

[0083] Due to the shallow installation position of the stirring device and the large aspect ratio of the anoxic reaction tank 7, a laminar flow can be formed in the anoxic reaction tank 7. The muddy water in the upper part consumes part of the dissolved oxygen through sufficient stirring and biological reaction, and the water flow in the lower part is gentle, which can ensure a better anoxic environment. Therefore, the denitrification efficiency can be guaranteed when the internal reflux is increased.

[0084] After entering the aerobic zone 81, the mixed mud and water, under the action of the bottom aeration plate, exerts an upward force on the mud-water mixture, and forms good mixing conditions in the anoxic reaction tank 7. The mud and water rise to the upper connecting pipe 91 and enter the anoxic zone 71, thereby completing the gravity circulation. The upper connecting pipe 91 is installed 1.0m away from the top of the tank. Both the anoxic reaction tank 7 and the aerobic reaction tank 8 have a 0.2m diameter opening connected to the upper connecting pipe 91.

[0085] A butterfly valve 6 is installed in the middle of the upper connecting pipe 91. In actual operation, the return flow rate is determined by the influent flow rate and the return sludge flow rate when the connecting pipe is full. The return flow rate is then controlled by the opening and closing of the butterfly valve 6. In actual operation, the return flow rate can be adjusted according to changes in water quality to fully utilize the influent carbon source for denitrification.

[0086] In this system, the reaction tank has a water inlet 10, a return sludge outlet 11, a water outlet 12, and an internal reflow outlet 13. According to different changes in water quality, the following parameters can be adjusted: the water inlet flow of the lifting pump and the water depth of the anoxic reaction tank 7 can be adjusted to change the hydraulic retention time of the system; the internal reflow flow can be adjusted by adjusting the butterfly valve 6 switch to change the denitrification efficiency. These two parameters are independent of each other.

[0087] After the circulation is complete, the muddy water overflows through the outlet 12 at the top of the aeration tank and enters the subsequent sedimentation tank for mud-water separation. The sludge returning from the sedimentation tank is returned to the anoxic zone 71 by a sludge pump. A return sludge port 11 is provided 1.5 meters from the top of the anoxic zone 71 for sludge return to ensure that the returned sludge is fully stirred. At this point, the muddy water in the system re-enters the next cycle of biological reaction.

Claims

1. A pumpless self-operation method for an automatically lifting two-stage A / O reaction pool, characterized in that: include: 1) Setting a self-operating system: comprising an anoxic reaction tank (7) and an aerobic reaction tank (8) two-stage cylindrical reaction tank, wherein the height-to-diameter ratio of the anoxic reaction tank is not less than 3, and the height-to-diameter ratio of the aerobic reaction tank is not less than 4; the water area in the anoxic reaction tank (7) is an anoxic area (71), and the water area in the aerobic reaction tank (8) is an aerobic area (81); the bottom of the aerobic reaction tank (8) is supported on the ground; the anoxic reaction tank (7) is fixed on an upper and lower telescopic frame (3) supported on the ground, and the bottom of the anoxic reaction tank (7) is higher than that of the aerobic reaction tank (8); An impeller (2) is horizontally installed in the anoxic reaction tank, and the installation height of the impeller (2) from the bottom of the tank is 1 / 2 of the water depth in the tank; the impeller has a hyperbolic blade and is driven to rotate by the stirrer (1); a vertical water inlet pipe is arranged at the center of the impeller (2), and the water inlet pipe is connected to the water inlet tank through a water delivery pipe and a lifting pump outside the tank; The bottom of the anoxic reaction tank is connected to the aerobic reaction tank obliquely downward through a lower connecting pipe (9), and an aeration device (5) is arranged at the bottom of the aerobic reaction tank; the upper part of the aerobic reaction tank is connected to the anoxic reaction tank through a horizontally arranged upper connecting pipe (91) and connects the anoxic zone and the aerobic zone, and the upper connecting pipe is located above the impeller; 2) Operation of the anoxic reaction tank: after the sewage is pumped from the water inlet tank to the top of the anoxic reaction tank by the lifting pump, it is transported to the center of the impeller (2) installed in the anoxic reaction tank (7) through a plumb vertical water inlet pipe to enter the tank; the outer diameter of the impeller blades is controlled to be 1 / 2 to 2 / 3 of the diameter of the anoxic zone (71) in the tank, and the mixer (1) is driven to rotate to slowly stir the muddy water in the tank, and the stirring speed is controlled within the range of 60 to 70 r / min, so that a small power is used to obtain a large area of ​​uniform water flow; the muddy water in the anoxic zone (71) at the top of the impeller is fully stirred, and partial anoxic denitrification occurs, and the slow stirring reduces the influence of the turbulence generated by the impeller stirring on the water flow at the bottom of the impeller in the anoxic zone (71); because the mixer is far away from the bottom of the anoxic zone (71), the stirring force at the bottom of the anoxic zone is small, forming a gentle water flow; 3) Operation of the aerobic reaction tank: under the top-down pressure applied to the water body by the internal and external water inflow of the anoxic reaction tank (7), the muddy water flows into the aerobic reaction tank through the bottom of the anoxic zone (71) through the lower connecting pipe (9) arranged obliquely downward and connected to the lower part of the wall of the aerobic reaction tank. At the same time, the muddy water in the aerobic zone (81) of the aerobic reaction tank rises under the aeration of the aeration device (5) at the bottom of the pool, and flows into the anoxic zone through the upper connecting pipe (91) horizontally connected to the anoxic reaction tank at the upper part of the pool wall to realize pump-free gravity circulation; The anoxic reaction tank and the aerobic reaction tank are operated back and forth in this way to realize pump-free gravity circulation.

2. The pumpless self-operation method of the two-stage A / O reaction pool with automatic lifting as claimed in claim 1, characterized in that: In the step (1), the height of the bottom of the anoxic reaction pool (7) from the ground is adjusted by telescoping the upper and lower telescopic frames, and the height of the anoxic zone (71) from the ground and the water depth of the anoxic zone are adjusted synchronously; the higher the height of the anoxic zone (71) from the ground, the shallower the water depth of the anoxic zone (71) and the smaller the water volume; under the premise that the water inlet flow rate remains unchanged, the smaller the water volume, the shorter the hydraulic retention time of the anoxic pool, so as to control the anoxic / aerobic hydraulic retention time ratio.

3. The pumpless self-operation method of the two-stage A / O reaction pool with automatic lifting as claimed in claim 2, characterized in that: A circular hole with a diameter of 0.2 m is opened at the center of the bottom of the anoxic reaction tank. A circular hole with a diameter of 0.2 m is also opened on the wall of the aerobic reaction tank (8) at a distance of 1.5 m from the bottom of the aerobic reaction tank and is lower than the bottom of the anoxic reaction tank. The two circular holes are connected to a lower connecting pipe (9) to receive muddy water after the reaction in the anoxic reaction tank (7).

4. The pumpless self-operation method of the two-stage A / O reaction pool with automatic lifting as claimed in claim 3, characterized in that: The upper connecting pipe (91) is installed below the liquid level of 1.0 m from the top liquid level of the aerobic reaction tank and above the impeller, and is connected to the side wall openings of the anoxic reaction tank (7) and the aerobic reaction tank (8) and maintained in a horizontal arrangement, and the diameter of the side wall opening is 0.2 m; a butterfly valve (6) is arranged on the upper connecting pipe to control the water flow; a plurality of openings are arranged at intervals from top to bottom on the side wall of the anoxic reaction tank (7) and valves are arranged respectively to adjust the connection position corresponding to the upper connecting pipe; a sludge return port (11) is arranged on the wall of the anoxic reaction tank above the impeller below the liquid level.

5. The pumpless self-operation method of the two-stage A / O reaction pool with automatic lifting as claimed in claim 1, characterized in that: Also includes: 4) Changing the hydraulic retention time of the system by adjusting the water flow rate of the lift pump or the water depth of the anoxic reaction tank (7); The hydraulic retention time is equal to the ratio of the reactor volume to the water inlet flow rate; the internal reflux flow rate is adjusted by adjusting the opening and closing of the butterfly valve (6).

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