Secondary sedimentation tank

Abstract

The utility model discloses a secondary sedimentation tank which comprises a tank body, the central cylinder is mounted in the tank body and connected with a water inlet pipe, and sewage enters the central cylinder from the water inlet pipe; the effluent weir is positioned at the upper part of the tank body, and clear water is discharged from the effluent weir after sewage enters the tank body to be settled; the sludge outlet pipe is used for discharging sludge settled at the bottom of the tank body out of the tank body; wherein a reflecting plate is arranged below the central cylinder, and sewage from the central cylinder flows through the reflecting plate and then enters the tank body. Compared with the prior art, the secondary sedimentation tank has the advantages that the reflecting plate is arranged below the central cylinder, and sewage from the central cylinder flows through the reflecting plate and then enters the tank body, so that the flow direction of the sewage can be changed, and the sewage is prevented from directly impacting the bottom of the secondary sedimentation tank.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, and more specifically, it relates to a secondary sedimentation tank. Background Technology

[0002] Secondary sedimentation tanks are an important component of wastewater treatment systems. They are mainly used to settle the mixed wastewater flowing out of biological treatment tanks, separating suspended solids (sludge) and clear water. The separated sludge is further concentrated and then dewatered, while the clear water is treated through advanced treatment / disinfection processes to meet discharge standards.

[0003] In related technologies, secondary sedimentation tanks typically adopt an inverted cone design. After mixed wastewater passes through coarse screens, fine screens, grit chambers, and a modified AAO treatment system, it enters the central cylinder through a gravity inlet pipe. After sludge-water separation, the sludge settles to the bottom of the secondary sedimentation tank and is discharged through a sludge discharge pipe, while the clear water is discharged through an outlet weir and enters the next process stage.

[0004] However, the secondary sedimentation tank in the relevant technology has at least the following drawbacks:

[0005] First, the outlet of the central cylinder of the secondary sedimentation tank is close to the bottom of the secondary sedimentation tank (1.6m). The incoming water easily disturbs the sludge accumulated at the bottom of the secondary sedimentation tank. When the inflow is large, the sludge accumulated at the bottom is easily impacted, resulting in sludge overturning. Even by adjusting the conventional process parameters, it is impossible to effectively avoid sludge overturning.

[0006] Secondly, since the secondary settling tank has a conical structure, the surface load varies at different heights. Therefore, the average surface load of the secondary settling tank is calculated using the area at the midpoint height, which is 2.12m. 3 / m 2 •h, higher than the recommended value in the outdoor drainage design code (0.6-1.5m) 3 / m 2 ·h), excessive surface load makes it difficult for sludge in the secondary sedimentation tank to settle.

[0007] In view of this, it is indeed necessary to provide a secondary sedimentation tank that can ensure smooth operation of the secondary sedimentation tank and that the effluent meets the standards. Utility Model Content

[0008] The purpose of this invention is to overcome at least one defect of the prior art and provide a secondary sedimentation tank to ensure smooth operation of the secondary sedimentation tank and that the effluent meets the standards.

[0009] To achieve the above-mentioned objectives, this utility model provides a secondary sedimentation tank, comprising:

[0010] Pool body;

[0011] A central cylinder is installed in the pool body, and the central cylinder is connected to an inlet pipe, through which sewage enters the central cylinder.

[0012] An outlet weir, located at the upper part of the pool, allows wastewater to settle within the pool before clear water is discharged through the outlet weir; and

[0013] The sludge discharge pipe is used to discharge the sludge that has settled at the bottom of the pool into the pool.

[0014] The feature is that a reflector plate is provided below the central cylinder, and the sewage from the central cylinder flows through the reflector plate and then enters the pool.

[0015] According to one embodiment of the secondary sedimentation tank of this utility model, the size of the reflector plate is larger than the cross-sectional size of the central cylinder.

[0016] According to one embodiment of the secondary sedimentation tank of this utility model, the central cylinder is cylindrical, the reflector is conical, and the diameter of the central cylinder is smaller than the maximum cross-sectional diameter of the reflector.

[0017] According to one embodiment of the secondary sedimentation tank of this utility model, the angle between the reflector plate and the horizontal plane is 17-20 degrees, preferably 17 degrees.

[0018] According to one embodiment of the secondary sedimentation tank of this utility model, the reflector is welded to the central cylinder by steel strips.

[0019] According to one embodiment of the secondary sedimentation tank of this utility model, an inclined tube is provided above the secondary sedimentation tank. The height of the inclined tube from the liquid surface of the tank body is 0.7-1 meter, preferably 1 meter, and the inclination is 60-70 degrees, preferably 60 degrees. After the inclined tube is laid, it is 6.5-6.7 meters away from the bottom of the tank body, preferably 6.7 meters.

[0020] According to one embodiment of the secondary sedimentation tank of this utility model, the inclined tube is provided with a lower support and an upper support.

[0021] According to one embodiment of the secondary sedimentation tank of this utility model, the lower support of the inclined tube includes mounting holes spaced apart around the tank body, angle steel fixedly installed in the mounting holes, and steel wires and turnbuckles connecting the opposite angle steels.

[0022] According to one embodiment of the secondary sedimentation tank of this utility model, the upper support of the inclined tube includes mounting holes spaced apart around the tank body, angle steel fixedly installed in the mounting holes, and steel wires and turnbuckles connecting the opposite angle steels.

[0023] According to one embodiment of the secondary sedimentation tank of this utility model, the distance between the bottom end of the central cylinder and the bottom of the tank body is 3.6-4 meters, preferably 3.6 meters.

[0024] Compared to existing technologies, in the secondary sedimentation tank of this invention, a reflector plate is installed below the central cylinder. Wastewater from the central cylinder flows through the reflector plate before entering the tank body, thus changing the direction of wastewater flow and preventing wastewater from directly impacting the bottom of the secondary sedimentation tank, ensuring smooth operation of the secondary sedimentation tank and meeting the effluent standards. Attached Figure Description

[0025] The secondary sedimentation tank of this utility model and its technical effects will be described in detail below with reference to the accompanying drawings and specific embodiments, wherein:

[0026] Figure 1 This is a schematic diagram of the secondary sedimentation tank of this utility model.

[0027] Figure 2 This is a schematic diagram showing the installation of the central cylinder and the reflector plate in the secondary sedimentation tank of this utility model.

[0028] Figure 3 This is a schematic diagram of the installation of the inclined tube in the secondary sedimentation tank of this utility model.

[0029] in:

[0030] 10--Pool body; 100--Outlet weir; 20--Central cylinder; 30--Reflector plate; 40--Inclined tube; 400--Lower support; 402--Upper support. Detailed Implementation

[0031] To make the invention's objective, technical solution, and technical effects clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described in this specification are merely for explaining the present invention and are not intended to limit the present invention.

[0032] Please refer to Figures 1 to 3 As shown, the secondary sedimentation tank of this utility model includes:

[0033] Pool body 10;

[0034] The central cylinder 20 is installed in the pool body 10. The central cylinder 20 is connected to an inlet pipe (not shown), and sewage enters the central cylinder 20 from the inlet pipe.

[0035] The outlet weir 102 is located at the upper part of the pool body 10. After the sewage enters the pool body 10 and settles, the clear water is discharged from the outlet weir 102; and

[0036] The sludge discharge pipe (not shown) is used to discharge the sludge settled at the bottom of the tank 10 into the tank 10.

[0037] The central cylinder 20 is equipped with a reflector plate 30 below it. The sewage from the central cylinder 20 does not directly impact the sludge settled on the bottom plate of the tank 10, but flows through the reflector plate 30 and then enters the tank 10.

[0038] According to one embodiment of the secondary sedimentation tank of this utility model, the size of the reflector plate 30 is larger than the cross-sectional size of the central cylinder 20. Figure 2 In the embodiment shown, the central cylinder 20 is cylindrical and the reflector 30 is conical. The diameter of the central cylinder 20 is smaller than the maximum cross-sectional diameter of the reflector 30. The reflector 30 is welded to the outer wall of the central cylinder 20 by four steel bars.

[0039] According to one embodiment of the secondary sedimentation tank of this utility model, the reflector plate 30 is inclined relative to the horizontal plane. For example, the angle between the reflector plate 30 and the horizontal plane is 17-20 degrees, preferably 17 degrees.

[0040] Please refer to the above as well. Figure 1 and Figure 3 As shown, according to one embodiment of the secondary sedimentation tank of this utility model, an inclined tube 40 is provided above the secondary sedimentation tank. The height of the inclined tube 40 from the liquid surface of the tank body 10 is 0.7-1 meter, preferably 1 meter, and the inclination is 6-70 degrees, preferably 60 degrees. After the inclined tube 40 is laid, it is 6.5-6.7 meters, preferably 6.7 meters, from the bottom of the tank body 10. The inclined tube 40 is provided with a lower support 400 and an upper support 402. The lower support 400 includes mounting holes spaced around the tank body 10, angle steel fixedly installed in the mounting holes, and steel wires and turnbuckles connecting the opposite angle steels; the upper support includes mounting holes spaced around the tank body 10, angle steel fixedly installed in the mounting holes, and steel wires and turnbuckles connecting the opposite angle steels.

[0041] Specifically, the installation process of the lower support 400 is as follows: holes are drilled at 200mm intervals around the secondary sedimentation tank to fix angle steel. After the angle steel is fixed, one side of the angle steel is fixed with 8mm steel wire, and the other side is connected to the steel wire fixed on the opposite side with turnbuckles. The installation process of the upper support 402 is as follows: holes are drilled at 200mm intervals around the secondary sedimentation tank to fix angle steel, and the angle steel is fixed on both sides with 4mm steel wire. Using nylon rope and steel wire as the main body of the upper support 402 and the lower support 400 respectively can effectively reduce the weight of the inclined tube 40.

[0042] Inclined tubes (40mm diameter) can increase the sedimentation area of ​​the secondary sedimentation tank, thereby improving its sedimentation efficiency. According to design specifications, the surface loading rate of an inclined tube sedimentation tank can be twice that of a conventional sedimentation tank, meaning the expanded surface loading rate is 1.2-3 m². 3 / m 2 •h, average surface loading of sedimentation tank is 2.12m 3The water volume is within the recommended range (m²·h). The secondary sedimentation tank can meet the needs of a treatment scale of 10,000 tons / day, and theoretically, the treatment capacity of the secondary sedimentation tank can reach 13,000 tons / day.

[0043] According to one embodiment of the secondary sedimentation tank of this utility model, the distance between the bottom end of the central cylinder 20 and the bottom of the tank body 10 is 3.6-4 meters, preferably 3.6 meters.

[0044] Based on the above detailed description of the embodiments of this utility model, it can be seen that, compared with the prior art, the secondary sedimentation tank of this utility model has the following technical effects:

[0045] First, a reflector plate 30 is installed below the central cylinder 20. Sewage from the central cylinder 20 flows through the reflector plate 30 and then enters the tank body 10. Therefore, the direction of sewage flow can be changed to avoid sewage directly impacting the bottom of the secondary sedimentation tank, ensuring smooth operation of the secondary sedimentation tank and that the effluent meets the standards.

[0046] Secondly, an inclined tube 40 is added to the secondary sedimentation tank to increase the sedimentation area and improve the sedimentation efficiency.

[0047] Finally, nylon rope and steel wire are used as the main body of the upper support 402 and lower support 400 of the inclined tube 40, respectively, which can effectively reduce the weight of the support.

[0048] Based on the above principles, appropriate changes and modifications can be made to the above-described embodiments. Therefore, this utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to this utility model should also fall within the protection scope of the claims of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.

Claims

1. A secondary sedimentation tank, comprising: Pool body; A central cylinder is installed in the pool body, and the central cylinder is connected to an inlet pipe, through which sewage enters the central cylinder. The outlet weir is located at the upper part of the pool. After the sewage enters the pool and settles, the clear water is discharged from the outlet weir. as well as The sludge discharge pipe is used to discharge the sludge that has settled at the bottom of the pool into the pool. The feature is that a reflector plate is provided below the central cylinder, and the sewage from the central cylinder flows through the reflector plate and then enters the pool.

2. The secondary sedimentation tank according to claim 1, characterized in that, The size of the reflector is larger than the cross-sectional size of the central cylinder.

3. The secondary sedimentation tank according to claim 2, characterized in that, The central cylinder is cylindrical, and the reflector is conical. The diameter of the central cylinder is smaller than the maximum cross-sectional diameter of the reflector.

4. The secondary sedimentation tank according to claim 1, characterized in that, The angle between the reflector and the horizontal plane is 17-20 degrees.

5. The secondary sedimentation tank according to claim 1, characterized in that, The reflector is welded to the central cylinder by steel bars.

6. The secondary sedimentation tank according to claim 1, characterized in that, An inclined tube is installed above the secondary sedimentation tank. The height of the inclined tube from the liquid surface of the tank is 0.7-1 meter, and the inclination is 60-70 degrees. After the inclined tube is laid, it is 6.5-6.7 meters away from the bottom of the tank.

7. The secondary sedimentation tank according to claim 6, characterized in that, The inclined tube is equipped with a lower support and an upper support.

8. The secondary sedimentation tank according to claim 7, characterized in that, The lower support of the inclined tube includes mounting holes spaced around the pool body, angle steel fixedly installed in the mounting holes, and steel wires and turnbuckles connecting the opposite angle steels.

9. The secondary sedimentation tank according to claim 7, characterized in that, The upper support of the inclined tube includes mounting holes spaced around the pool body, angle steel fixedly installed in the mounting holes, and steel wires and turnbuckles connecting the opposite angle steels.

10. The secondary sedimentation tank according to any one of claims 1 to 9, characterized in that, The distance between the bottom of the central cylinder and the bottom of the pool body is 3.6-4 meters.

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