An oxidation ditch flow regime settling method

Abstract

The application discloses an oxidation ditch flow state sedimentation method, which is applied to an oxidation ditch flow state and comprises a sedimentation unit and a pushing device, and at least two stages of solid-liquid separators are arranged at intervals in the sedimentation unit; the specific steps are as follows: the oxidation ditch flow state is pushed by using the self-flow velocity of the oxidation ditch flow state or by the pushing device, so that a certain circulation velocity of the oxidation ditch flow state is generated; the sludge liquid with a certain flow velocity is separated layer by layer through the solid-liquid separators in the sedimentation unit, a circulation is formed in the cavity region between adjacent solid-liquid separators, and the particle content of the sludge liquid to the next stage of solid-liquid separator is reduced; the supernatant is discharged through the effluent weir of the sedimentation unit, the organic matter sludge liquid is backflowed to the sedimentation tank through the solid-liquid separator, and solid-liquid separation is realized; the oxidation ditch flow state is originally proposed in the method, and a high-efficiency sedimentation method is provided for the oxidation ditch flow state; compared with the traditional fixed and static sedimentation, the surface load is at least 2 m 3 / ㎡h.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and in particular to a fluidized sedimentation method in an oxidation ditch. Background Technology

[0002] Surface loading rate is one of the design parameters for sedimentation tanks in water supply and drainage treatment plants. When a suspended particle settles after traveling a distance exactly equal to the tank depth within the theoretical residence time, its settling velocity is called the overflow rate or surface loading rate.

[0003] In existing technologies, sedimentation tanks are generally constructed separately from biological treatment tanks, with a typical surface loading rate of 1 m³ / m²h. This settling rate is insufficient to separate organic matter and filtrate from existing sludge and wastewater. Summary of the Invention

[0004] The purpose of this invention is to provide a fluidized bed sedimentation method for oxidation ditches, which addresses the above-mentioned problems and solves the issues of low surface load of sedimentation devices and low utilization rate of the bottom volume of sedimentation tanks, which can only be used for sedimentation and sludge accumulation.

[0005] This invention is achieved through the following scheme:

[0006] An oxidation ditch fluidized bed sedimentation method includes a sedimentation unit and a propulsion device, wherein the sedimentation unit includes at least two stages of solid-liquid separators arranged at intervals; the specific steps are as follows:

[0007] The oxidation ditch flow is propelled by its own velocity or by a driving device (or pump suction) to generate a certain circulation velocity.

[0008] Sludge with a certain flow rate is separated layer by layer by the solid-liquid separator in the settling unit. A circulation is formed in the cavity area between adjacent solid-liquid separators, which reduces the particle content of the sludge in the next stage solid-liquid separator.

[0009] The supernatant is discharged through the effluent weir of the settling unit, while the organic sludge is returned to the settling tank through the solid-liquid separator, thus achieving solid-liquid separation.

[0010] Furthermore, the circulation velocity of the oxidation ditch is not less than 0.4 m / s.

[0011] Furthermore, the bottom of the settling unit is at least 1m away from the bottom of the settling tank.

[0012] Furthermore, the settling unit includes a connector, a first solid-liquid separator, a second solid-liquid separator, and a housing; the connector is disposed on the housing, and the first solid-liquid separator and the second solid-liquid separator are spaced apart in the housing along the liquid flow direction, so that a turbulence cavity is formed between the first solid-liquid separator and the second solid-liquid separator; the sidewall of the turbulence cavity is at an angle of 20 to 50° to the sidewall of the first filter cavity.

[0013] Furthermore, the sedimentation unit has a first filter chamber at its inlet that matches the size and shape of the first solid-liquid separator, and the first solid-liquid separator is assembled in the first filter chamber.

[0014] Furthermore, the turbulence cavity includes a first port and a second port. The aperture of the first port is adapted to the first filter cavity, and the size of the second port is not smaller than that of the first port, so that the turbulence cavity presents an enlarged structure. The size of the second port is adapted to the second solid-liquid separator.

[0015] Furthermore, the height of the first solid-liquid separator is 0.5 to 0.8 m, the vertical distance between the first port and the second port is at least 1 m, and the height of the second solid-liquid separator is 0.5 to 1.0 m.

[0016] Furthermore, a water outlet weir is provided inside the outer casing, and the distance between the water outlet weir and the water outlet of the second solid-liquid separator is at least 0.8m.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0018] 1. This method innovatively proposes an oxidation ditch flow state and provides a high-efficiency sedimentation method for the oxidation ditch flow state. Compared with traditional fixed static sedimentation, its surface load reaches at least 4 m3 / ㎡h, which can achieve high sedimentation efficiency in a small volume, and enable efficient separation of clear liquid and organic matter in the sedimentation tank.

[0019] 2. In this scheme, the first solid-liquid separator and the second solid-liquid separator are spaced apart in the shell along the direction of liquid flow, so that a turbulence cavity is formed between the first solid-liquid separator and the second solid-liquid separator. In the turbulence cavity, the upward water flow and the downward mud flow will form a dynamic balance suspension layer, which can make the mud liquid entering the second solid-liquid separator have a lower particle size, thus increasing the overall sludge removal effect and controlling the effluent SS to within 10mg / L.

[0020] 3. The space at the bottom of the sedimentation tank can be used as part of the biological treatment tank, which improves the utilization rate of the tank volume. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the flow pattern in an oxidation ditch of a fixed settling unit.

[0022] Figure 2 This is a schematic diagram of the flow pattern in a forced oxidation ditch of a fixed settling unit;

[0023] Figure 3 This is a schematic diagram of the flow state of the oxidation ditch in the detachable settling unit;

[0024] Figure 4 This is a schematic diagram of the forced oxidation channel flow in a detachable settling unit;

[0025] Figure 5 This is a schematic diagram of the settlement unit structure;

[0026] Figure descriptions: 1. Fixing frame; 2. Settling unit; 3. Fixing frame; 4. Settling tank; 5. Pump; 6. Pushing assembly; 21. Connecting component; 22. First solid-liquid separator; 23. Second solid-liquid separator; 24. Outer shell; 25. Turbulence chamber; 26. First port; 27. Second port; 28. Effluent weir; 29. ​​First filtration chamber. Detailed Implementation

[0027] All features disclosed in this specification, or steps in all methods or processes disclosed herein, may be combined in any way, except for mutually exclusive feature steps.

[0028] Any feature disclosed in this specification (including any appended claims and abstract) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0029] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0031] This scheme defines the flow regime in the oxidation ditch, such as... Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, during the installation of a fixed or detachable settling device, the settling tank 4 will form a circulation state with a certain speed inside it by pushing component 6, or by adding external thrust pump 5 to make the sludge-sewage mixture in the settling tank 4 form a circulation state with a certain flow rate.

[0032] Example 1

[0033] This invention provides a technical solution:

[0034] A fluidized sedimentation method for oxidation ditches, applied in a fluidized oxidation ditch, includes a sedimentation unit and a propulsion device. The sedimentation unit includes at least two stages of solid-liquid separators spaced at intervals. The specific steps are as follows:

[0035] The oxidation ditch flow is generated by its own velocity or by a driving device, so that the oxidation ditch flow has a certain circulation velocity.

[0036] Sludge with a certain flow rate is separated layer by layer by the solid-liquid separator in the settling unit. A dynamic balance suspension layer is formed in the cavity area between adjacent solid-liquid separators, which reduces the particle content of the sludge in the next stage solid-liquid separator.

[0037] The supernatant is discharged through the effluent weir of the settling unit, while the organic sludge is returned to the settling tank through the solid-liquid separator, thus achieving solid-liquid separation.

[0038] In this scheme, the circulation velocity of the oxidation ditch is not less than 0.4 m / s. When the circulation velocity is less than 0.4 m / s, the sludge cannot efficiently enter the solid-liquid separator for multi-stage filtration, and circulation cannot be formed in the cavity area between adjacent solid-liquid separators.

[0039] Meanwhile, when it is necessary to drive the components to circulate, a circulation speed of 0.4 m / s is the minimum power consumption required to drive the components to meet the requirements of multi-stage sludge separation. At this circulation speed, the normal operation of the multi-stage solid-liquid separator in this solution can be guaranteed.

[0040] As an example, the bottom of the settling unit is at least 1m away from the bottom of the settling tank, so that the settling unit is far enough away from the bottom to reduce the impact of the settling unit on the flow velocity of the oxidation ditch, reduce the energy consumption required when the components need to be pushed, and ensure that the whole process is carried out with low power consumption.

[0041] As an example, such as Figure 5As shown, the settling unit 2 may include at least a connector 21, a first solid-liquid separator 22, a second solid-liquid separator 23, and a housing 24; the connector 21 is disposed on the housing 24, and the first solid-liquid separator 22 and the second solid-liquid separator 23 are spaced apart in the housing 24 along the liquid flow direction, so that a turbulence cavity 25 is formed between the first solid-liquid separator 22 and the second solid-liquid separator 23; the sidewall of the turbulence cavity 25 may be at an angle of 20 to 50° with the sidewall of the first filter cavity 29.

[0042] In this oxidation ditch flow state, the sewage itself has a certain flow velocity. That is, sewage with a certain velocity enters the settling unit 2 from the first solid-liquid separator 22. During the process of sewage rising, small particles of sludge also enter the first solid-liquid separator 22. Some of the sludge will fall onto the inclined tube. After the small particles of sludge accumulate on the inclined tube to a certain extent, they will slide off the surface of the inclined tube and fall to the bottom of the settling tank 4. Some of the sludge and sewage mixture will pass through the first solid-liquid separator 22 with the flow, forming an upward water flow in the turbulence chamber 25, and then enter the second solid-liquid separator 23. Since the side wall of the turbulence chamber 25 is at an angle of 20 to 50° with the side wall of the first filter chamber 29, it forms a dispersion shape. When the sludge comes out of the first solid-liquid separator, the flow velocity will slow down as the space increases.

[0043] Similarly, wastewater with a certain speed enters the rear end position from the second solid-liquid separator 23. During the process of the wastewater rising, small particles of sludge also enter the second solid-liquid separator 23. Some of the sludge will fall onto the inclined tube. After the small particles of sludge accumulate on the inclined tube to a certain extent, they will slide off the surface of the inclined tube and fall into the turbulence chamber 25. The detached sludge forms a downward sludge flow in the turbulence chamber 25.

[0044] At this time, in the turbulence chamber 25, the upward water flow and the downward mud flow will form a dynamic balance suspension layer. The dynamic balance suspension layer can block the mud entering the second solid-liquid separator 23, reduce its particle size, and increase the overall sludge removal effect, so that the surface load of this device can be no less than 2m3 / ㎡h.

[0045] As an example, a first filter chamber 29, whose size and shape match the first solid-liquid separator 22, is provided at the inlet of the sedimentation unit 2, and the first solid-liquid separator 22 is assembled in the first filter chamber 29.

[0046] The turbulence cavity 25 includes at least a first port 26 and a second port 27. The aperture of the first port 26 is adapted to the first filter cavity 29. The size of the second port 27 is not smaller than that of the first port 26, so that the turbulence cavity 25 presents an enlarged structure. The size of the second port 27 is adapted to the second solid-liquid separator 23.

[0047] Based on the above structure, sewage enters the turbulence chamber 25 from the first solid-liquid separator 22. Due to the enlarged structure of the turbulence chamber 25, the flow rate of the liquid entering the turbulence chamber 25 from the first solid-liquid separator 22 suddenly slows down, which can better form a backflow with the decreased flow rate.

[0048] As an example, the cavity structure of the turbulence cavity 25 is a frustum-shaped structure, and the sidewalls of the turbulence cavity 25 are smoothly arranged to reduce the influence of the sidewalls of the turbulence cavity 25 on the internal circulation of the turbulence cavity 25.

[0049] As an example, the height of the first solid-liquid separator 22 can be 0.4 to 1.0 m, the vertical distance between the first port 26 and the second port 27 is at least 1 m, and the height of the second solid-liquid separator 23 can be 0.7 to 1.2 m.

[0050] As an example, an outlet weir 28 is provided inside the outer shell 24. After the second solid-liquid separator 23 discharges water, the supernatant flows out through the outlet weir 28, which can eventually separate the organic matter and the supernatant. The organic matter is eventually returned to the sedimentation tank 4 for further processing.

[0051] The distance between the outlet weir 28 and the outlet of the second solid-liquid separator 23 is at least 0.8m, so that the supernatant has enough settling space to ensure the cleanliness of the effluent.

[0052] This method innovatively proposes an oxidation ditch flow state and provides a high-efficiency sedimentation method for the oxidation ditch flow state. Compared with traditional fixed static sedimentation, its surface load reaches at least 2 m3 / ㎡h, which can achieve high sedimentation efficiency in a small volume, enabling efficient separation of clear liquid and organic matter in the sedimentation tank.

[0053] In this scheme, the first and second solid-liquid separators can be inclined tube assemblies.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for sedimentation in an oxidation ditch, applied in the flow state of an oxidation ditch, characterized in that: It includes a settling unit and a propulsion device, wherein the settling unit includes at least two stages of solid-liquid separators arranged at intervals; the specific steps are as follows: The oxidation ditch flow is generated by its own velocity or by a driving device, so that the oxidation ditch flow has a certain circulation velocity. Sludge with a certain flow rate is separated layer by layer by the solid-liquid separator in the settling unit. A dynamic balance suspension layer is formed in the cavity area between adjacent solid-liquid separators, which reduces the particle content of the sludge in the next stage solid-liquid separator. The supernatant is discharged through the effluent weir of the settling unit, and the organic sludge is returned to the settling tank through the solid-liquid separator to achieve solid-liquid separation. The sedimentation unit is provided with a first filter chamber at its inlet, which is the same size and shape as the first solid-liquid separator, and the first solid-liquid separator is assembled in the first filter chamber. The settling unit includes a connector, a first solid-liquid separator, a second solid-liquid separator, and a housing; the connector is disposed on the housing, and the first solid-liquid separator and the second solid-liquid separator are spaced apart in the housing along the liquid flow direction, so that a turbulence cavity is formed between the first solid-liquid separator and the second solid-liquid separator; The sidewall of the turbulence cavity forms an angle of 20-50° with the sidewall of the first filter cavity; The turbulence cavity includes a first port and a second port. The aperture of the first port is adapted to the first filter cavity, and the size of the second port is not smaller than that of the first port, so that the turbulence cavity presents an enlarged structure. The size of the second port is adapted to the second solid-liquid separator. The circulation velocity of the oxidation ditch is not less than 0.4 m / s. The height of the first solid-liquid separator is 0.5~0.8 m, the vertical distance between the first port and the second port is at least 1 m, and the height of the second solid-liquid separator is 0.5~1 m. The cavity structure of the turbulence cavity is a frustum-shaped structure, and the sidewalls of the turbulence cavity are smoothly arranged.

2. The oxidation ditch fluidized bed sedimentation method as described in claim 1, characterized in that: The bottom of the settling unit is at least 1m away from the bottom of the settling tank.

3. The oxidation ditch fluidized bed sedimentation method as described in claim 2, characterized in that: The outer casing is provided with a water outlet weir, and the distance between the water outlet weir and the water outlet of the second solid-liquid separator is at least 0.8m.

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