Circumferential-in and circumferential-out radial-flow sedimentation tank

Abstract

The utility model provides a circumferential-in and circumferential-out radial-flow sedimentation tank, which relates to the field of sewage treatment and comprises a tank body consisting of a tank wall and a bottom plate, an annular table is arranged above the pool wall, a first surrounding plate and a second surrounding plate are sequentially arranged on the annular table from outside to inside, a water inlet groove is formed between the first surrounding plate and the pool wall, the first surrounding plate and the second surrounding plate form a water outlet groove, the first surrounding plate is higher than the second surrounding plate, the water inlet groove is communicated with a sewage inlet, and water distribution holes communicated with the pool body are formed in the bottom of the water inlet groove; the annular grid device is arranged below the water outlet groove, and the grid device is provided with an inclined mud-water separation channel; the water guide plate is arranged on the grid device, and the upper end of the water guide plate is flush with or higher than the upper end of the second surrounding plate, the water outlet flow path is prolonged in a peripheral inlet and peripheral outlet mode, the retention time of sewage in the tank body is prolonged, floc particles are fully precipitated, and the separation effect is better.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment, and in particular to a radial flow sedimentation tank with circumferential inlet and outlet. Background Technology

[0002] A secondary sedimentation tank is a common facility in wastewater treatment plants, typically located in the secondary treatment stage, used to further remove suspended solids and some dissolved substances from the water. Its main function is to remove residual suspended particles from the water through gravity settling, ensuring that the effluent quality meets discharge standards or requires further treatment. After water enters the secondary sedimentation tank, the flow rate gradually slows down, and fine suspended solid particles begin to settle to the bottom of the tank due to gravity. The sediment (sludge) is collected at the bottom of the tank and periodically removed by sludge scrapers or other mechanical equipment. The supernatant (the water after sedimentation) overflows from the top of the tank and enters subsequent treatment stages or is directly discharged.

[0003] The most commonly used type of secondary sedimentation tank is the center-inlet, perimeter-outlet type, where wastewater flows in from the center of the tank, undergoes sedimentation and purification, and then the clear water is discharged circumferentially through the tank walls. Because the wastewater travels a relatively short distance within the tank, this structure limits the sludge removal capacity and overall wastewater treatment efficiency of the secondary sedimentation tank to some extent.

[0004] In addition, since sewage flows into the center of the pool, the sewage pipes are usually located below the bottom wall, which also presents the problem of inconvenience in construction, maintenance and renovation. Utility Model Content

[0005] This utility model provides a radial flow sedimentation tank with circumferential inlet and outlet, which aims to solve the problems of poor sedimentation effect and inconvenience in modification of existing secondary sedimentation tanks.

[0006] To achieve the above objectives, embodiments of this utility model provide a radial flow sedimentation tank with circumferential inlet and outlet, comprising:

[0007] A bottom plate and a pool wall disposed above the bottom plate, the pool wall and the bottom plate forming a pool body;

[0008] A ring platform is provided on the upper inner side of the pool wall. A first enclosure plate and a second enclosure plate are arranged sequentially from the outside to the inside on the ring platform. A water inlet channel is formed between the first enclosure plate and the pool wall. A water outlet channel is formed between the first enclosure plate and the second enclosure plate. The first enclosure plate is higher than the second enclosure plate. The water inlet channel is connected to a sewage inlet. Sewage flows unidirectionally along the water inlet channel. A water distribution hole connected to the pool body is provided at the bottom of the water inlet channel. The water distribution hole is arranged along the direction of sewage flow.

[0009] A ring-shaped mesh device is installed below the outlet trough. The mesh device is spaced apart from the pool wall to allow sewage to enter the pool directly. The mesh device has an inclined mud-water separation channel.

[0010] A water guide plate is installed on the grid device. The upper end of the water guide plate is flush with or higher than the upper end of the second enclosure plate. The water guide plate, the second enclosure plate, and the grid device surround each other to form a water storage area. Sewage enters the water storage area through the mud-water separation channel and forms clear water. The clear water flows into the water outlet tank. The water outlet tank is provided with a clear water outlet for the clear water to flow out.

[0011] Preferably, the water guide plate is disposed on the side of the grid device near the center. The water guide plate includes a first plate body and a second plate body. One end of the first plate body is connected to one end of the second plate body. The included angle between the first plate body and the second plate body is an obtuse angle. The upper end of the first plate body is flush with the upper end of the second enclosure plate. The second plate body is fixed on the grid device.

[0012] Preferably, the bottom plate is provided with a sludge discharge channel and a sludge discharge port connecting the sludge discharge channel and the pool body;

[0013] The radial flow sedimentation tank with circumferential inlet and outlet also includes a sludge treatment unit, which is located at the center of the bottom plate. The sludge treatment unit includes a sludge suction section and a sludge scraping section, which revolve around the center of the bottom plate. The sludge suction section is connected to the sludge discharge hole, and the sludge scraping section spreads the sludge evenly on the bottom plate.

[0014] Preferably, a water-stop plate is also provided in the water inlet tank, and the water-stop plate is located upstream of the sewage inlet;

[0015] The radial flow sedimentation tank with circumferential inlet and outlet also includes a slag collection unit, which includes a slag collection hopper and a slag skimming assembly. The slag collection hopper is located inside the ring platform.

[0016] A central column is provided at the center of the base plate, and the sludge treatment unit and the skimming component are rotatably mounted on the central column. The skimming component pushes the scum floating on the liquid surface into the scum collection hopper.

[0017] Preferably, the slag collection unit further includes a slag well and a slag collection pipe, the slag collection pipe connecting the slag collection hopper and the slag well, and an outer wall is provided around the periphery of the pool wall, the outer wall and the pool wall forming a slag well in the radial direction.

[0018] Preferably, the grid device includes a plurality of grid units, which are spliced ​​together to form the grid device. The grid device forms a first gap with the ring platform in the vertical direction and a second gap with the pool wall in the horizontal direction. A water baffle is provided in the second gap and is located below the water distribution hole. A water baffle skirt is provided in the first gap to prevent sewage from entering the first gap.

[0019] Preferably, the grid unit includes a packing frame, and the packing frame is arranged with inclined tubes or inclined plates. When the packing frame contains inclined plates, adjacent inclined plates form the mud-water separation channel.

[0020] Preferably, the longitudinal section of the base plate is conical, and a vent is formed at the center of the base plate. The vent is connected to a vent pipe located below the base plate, and the sludge scraper is attached to the base plate and rotates.

[0021] Preferably, the top ends of the suction section and the scraping section are vertically spaced from the mesh device.

[0022] The above-mentioned solution of this utility model has the following beneficial effects:

[0023] First, this application extends the effluent flow path by using a weekly inflow and outflow method, which allows the sewage to remain in the tank for a longer period of time, enabling the flocculent particles in the sewage to settle and resulting in better separation.

[0024] Secondly, by adding water guide plates and grid devices to the existing sedimentation tanks, the problem of the existing sedimentation tanks being unable to be modified due to land constraints was solved.

[0025] Finally, a first and a second enclosure are set on the ring platform to form an inlet trough and an outlet trough. The structure is simple. After sedimentation, the clear water flows into the outlet trough from the upper part of the second enclosure, which avoids turbulence in the process of the clear water flowing into the outlet trough.

[0026] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0027] Figure 1 This is a top view of the present invention;

[0028] Figure 2 This is a schematic diagram of the grid device layout;

[0029] Figure 3 yes Figure 1 Cross-sectional view of AA;

[0030] Figure 4 yes Figure 1 Cross-sectional view of BB;

[0031] Figure 5 yes Figure 1 Cross-sectional view of CC;

[0032] Figure 6 yes Figure 1 Enlarged view of section D

[0033] Figure 7 yes Figure 3 Enlarged view of section E in the middle;

[0034] Figure 8 This is a schematic diagram of a grid cell;

[0035] Figure 9 This is a schematic diagram of the water guide plate.

[0036] [Explanation of Labels in the Attached Image]

[0037] 100-Bottom plate, 110-Sludge discharge channel, 120-Sludge discharge port, 130-Sludge suction section, 140-Sludge scraping section, 150-Drainage port, 160-Drainage pipe

[0038] 200-pool wall,

[0039] 300-Circular platform, 310-First enclosure, 320-Second enclosure, 330-Water inlet trough, 331-Sewage inlet, 332-Water distribution hole, 333-Water stop plate

[0040] 340 - Water outlet tank, 341 - Clean water outlet, 342 - Water outlet pit

[0041] 400-Grid device, 410-Slurry-water separation channel, 420-Grid unit, 421-Packing frame, 422-Inclined plate, 430-Water baffle, 440-Water baffle skirt.

[0042] 500 - Water guide plate, 510 - First plate body, 520 - Second plate body

[0043] 610-Slag collection hopper, 620-Slag skimming assembly, 630-Slag well, 640-Slag collection pipe,

[0044] 700-Center Column

[0045] S - The flow path of the first wastewater. Detailed Implementation

[0046] To make the technical problems, technical solutions and advantages of this utility model clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0047] like Figure 1-9As shown, an embodiment of this utility model provides a radial flow sedimentation tank with circumferential inflow and outflow, including a bottom plate 100 and a tank wall 200, wherein both the bottom plate 100 and the tank wall 200 are circular, and the tank wall 200 is disposed on the bottom plate 100, forming a tank body with the bottom plate 100. A sludge discharge channel 110 and a sludge discharge port 120 are provided in the bottom plate 100, and the sludge discharge port 120 is connected to the sludge discharge channel 110 for discharging the settled sludge out of the tank body.

[0048] An annular platform 300 is also provided on the inner side of the pool wall 200, positioned above the pool wall 200. A first enclosure plate 310 and a second enclosure plate 320 are provided on the annular platform 300. The diameter of the first enclosure plate 310 is larger than the diameter of the second enclosure plate 320. The first enclosure plate 310 and the pool wall 200 form an inlet channel 330, and the first enclosure plate 310 and the second enclosure plate 320 form an outlet channel 340. A sewage inlet 331 is also provided on the inlet channel 330, connected to a sewage inlet pipe, through which sewage enters the inlet channel 330. Several water distribution holes 332 are provided within the inlet channel 330, arranged at the bottom of the channel, allowing sewage to enter the pool body. The water distribution holes 332 are positioned along the direction of sewage flow. In this application, the wastewater flows counterclockwise within the inlet tank 330. It should be noted that, since the water distribution holes 332 are arranged along the flow path of the wastewater, the flow rate of the upstream water distribution hole 332 is greater than that of the downstream water distribution hole 332 as the wastewater flows. The outlet tank 340 is provided with a clean water outlet 341 for supplying clean water. Preferably, the bottom of the outlet tank 340 is provided with an outlet pit 342, and the clean water outlet 341 is located on the outlet pit 342.

[0049] The aforementioned first enclosure 310 and second enclosure 320 are both set based on the ring platform 300, and the height of the first enclosure 310 is higher than the height of the second enclosure 320.

[0050] A ring-shaped mesh device 400 is also installed inside the tank, located below the effluent trough 340, with the mesh device 400 and the tank wall 200 spaced horizontally apart. The mesh device 400 has an inclined sludge-water separation channel 410. Flocculent particles flowing upward with the sewage adhere to the sludge-water separation channel 410, forming relatively large sludge particles. The sludge particles sink due to gravity, achieving the effect of sludge-water separation.

[0051] A water guide plate 500 is also provided on the grid device 400. The water guide plate 500 is also ring-shaped. The upper end of the water guide plate 500 is flush with or higher than the upper end of the second enclosure plate 320. The water guide plate 500, the second enclosure plate 320, and the grid device 400 surround each other to form a water storage area. The clean water passing through the mud-water separation channel 410 is temporarily stored in the water storage area. The clean water flows from above the second enclosure plate 320 into the water outlet trough 340.

[0052] When sewage enters the inlet tank 330, it enters the pool body at a certain initial velocity through the water distribution hole 332. The sewage flows along the preset flow path in the pool body. During the flow, the floc particles in the sewage separate from the clear water. The floc particles sink to the bottom plate 100 to form sludge, completing the first sedimentation. Subsequently, the sewage flows over the grid device 400 from below. Under the action of the grid device 400, the sludge and water are separated and sedimentation is completed. The clear water flows upward into the water storage area. When the liquid level in the water storage area is higher than the second enclosure plate 320, the clear water flows from the upper end of the second enclosure plate 320 into the outlet tank 340.

[0053] Below the grid device 400 is the sludge settling zone, where flocculent particles in the wastewater are separated from the clean water. Below the sludge settling zone is the sedimentation zone, where flocculent particles accumulate to form sludge.

[0054] In this application, the sludge flows with a flow path larger than the radius of the tank. During the flow, there is sufficient time and flow path for the separation of water and floc particles, thus the sedimentation effect of this application is better.

[0055] Preferably, the water guide plate 500 is disposed on the side of the grid device 400 near the center. The water guide plate 500 includes a first plate body 510 and a second plate body 520. One end of the first plate body 510 is connected to one end of the second plate body 520. The included angle α between the first plate body 510 and the second plate body 520 is an obtuse angle. The upper end of the first plate body 510 is flush with or higher than the upper end of the second enclosure plate 320. The second plate body 520 is fixed on the grid device 400.

[0056] Preferably, the water guide plate 500 can be set in two ways. When the first plate body 510 is closer to the center of the pool than the second plate body 520, the first plate body 510 and the second enclosure plate 320 are horizontally spaced apart, forming a water storage area in conjunction with the grid device 400.

[0057] When the first plate body 510 is farther away from the center of the pool than the second plate body 520, the first plate body 510 and the second enclosure plate 320 are horizontally spaced apart, forming a water storage pool in conjunction with the grid device 400.

[0058] Regardless of which of the two methods the guide plate 500 is arranged in, the first plate plays two roles. When sewage enters the pool and turns towards the outlet, some sewage will impact the grid device 400 and enter between the grid device 400 and the ring platform 300. On the one hand, it prevents the flocculent particles in the sewage from gradually settling above the grid device 400 and causing the grid device 400 to become blocked. On the other hand, it prevents unsedimented sewage from flowing into the outlet tank 340 from the upper end of the second enclosure plate 320.

[0059] Furthermore, as flocculent particles accumulate, a large amount of sludge will form in the sedimentation zone, thus requiring sludge removal. To this end, this application also includes a sludge treatment unit, located at the center of the base plate 100. The sludge treatment unit includes a sludge suction section 130 and a sludge scraping section 140, both revolving around the base plate 100. The sludge suction section 130 is connected to the sludge discharge port 120, and the sludge scraping section 140 spreads and distributes the sludge evenly, facilitating suction by the sludge suction section 130.

[0060] Preferably, the center of the base plate 100 is lower than the semicircle of the base plate 100, making the base plate 100 conical in longitudinal section. As the scraper 140 scrapes, the sludge moves along the base plate 100 from its edge to its center. A drain port 150 is provided at the center of the base plate 100, and the drain port 150 is connected to a drain pipe 160 located below the base plate 100.

[0061] Preferably, the scraper part 140 is attached to the base plate 100 and rotates.

[0062] The aforementioned water inlet trough 330 is also equipped with a water stop plate 333, which is located upstream of the sewage inlet 331.

[0063] Reference Figure 6 When the sewage flows counterclockwise, it enters the downstream of the inlet tank 330. The water stop plate 333 is set on the clockwise side of the sewage inlet 331, that is, the sewage flows counterclockwise in the inlet tank 330, and the central angle corresponding to the flow path is smaller than the circumferential angle.

[0064] Similarly, when the sewage flows clockwise, the water stop plate 333 is set in the counterclockwise direction of the sewage inlet 331, and the central angle corresponding to the sewage flow path is also smaller than the circumferential angle.

[0065] Preferably, the width of the inlet trough 330 gradually decreases along the flow direction. The purpose of reducing the width is to ensure that the sewage still has kinetic energy to flow to the last water distribution hole 332 after passing through each water distribution hole 332, in preparation for subsequent cleaning of scum.

[0066] This application also includes a slag collection unit, which is used to collect slag floating on the liquid surface. The slag is usually oily substances and floating matter such as algae.

[0067] The slag collection unit includes a slag collection hopper 610 and a slag skimming component 620. The slag collection hopper 610 is located inside the ring platform 300, and the slag skimming component is located at the center of the pool. The slag skimming component 620 rotates around the center of the pool, thereby pushing the floating slag around the ring platform 300 into the slag collection hopper for collection.

[0068] Furthermore, the slag collection unit also includes a slag discharge port for collecting slag in the inlet tank 330. The slag discharge port is located in the inlet tank 330 near the water stop plate 333. The slag discharge port and the sewage inlet 331 are respectively located on both sides of the water stop plate 333. As the sewage flows, the sewage carries the slag to the slag discharge port and is discharged from the inlet tank 330 through the slag discharge port.

[0069] To facilitate the collection of scum from the scum discharge port and the scum collection hopper 610, an outer wall is provided on the outside of the pool wall 200. The outer wall and the pool wall 200 form a scum well 630 in the radial direction. The scum well 630 is connected to the scum collection hopper 610 through a scum collection pipe 640, and the water inlet trough 330 is connected to the scum well 630 through the scum discharge port.

[0070] Furthermore, in order to support and install the sludge treatment unit and the skimming assembly 620, a central column 700 is also provided at the center of the tank. The aforementioned sludge treatment unit is located at the lower part of the central column 700, and the sludge scraping part 140 and the sludge suction part 130 are respectively rotatably mounted on the central column 700. Preferably, the sludge scraping part 140 and the sludge suction part 130 are centrally symmetrically mounted on the central column 700.

[0071] Similarly, the slag skimming unit is rotated on the upper part of the central column 700.

[0072] Preferably, the vent 150 and the mud discharge port 120 are located at the center column 700.

[0073] The aforementioned grid device 400 and ring platform 300 are vertically spaced to form a first gap, and the grid device 400 and pool wall 200 are horizontally spaced to form a second gap. When sewage is discharged into the pool through the water distribution holes 332, the sewage flows out through the second gap without passing through the grid device 400. A horizontal baffle plate 430 is provided in the second gap. The baffle plate 430 is located below each water distribution hole 332. When each water distribution hole 332 discharges water, the sewage acts on the baffle plate 430. On the one hand, this prevents the sewage from rushing straight down and failing to move along the preset path, thus shortening the path for sewage separation and sedimentation and affecting the sewage separation and sedimentation effect. On the other hand, the baffle plate 430 can accumulate flocculent particles in the sewage, causing the flocculent particles to agglomerate, which facilitates the separation of subsequent agglomerated flocculent particles. A longitudinal baffle 440 is installed within the first compartment. The baffle 440 is arranged in a ring at the bottom of the ring platform 300 and seals the first compartment, preventing sewage blocked by the baffle plate 430 from splashing into the first compartment and causing sludge to accumulate and clog the mesh device 400. In conjunction with the guide plate 500, sewage is prevented from entering the storage area horizontally.

[0074] The grid device 400 is assembled from several fan-shaped grid units 420 connected end to end. The grid device 400 is in a ring shape as a whole, and each grid unit 420 includes a packing frame 421. The packing frame 421 is fixed to the pool wall 200 and the ring platform 300 by interlacing steel wire ropes. A tensioner is installed between each steel wire rope and the anchor hook connected in the pool wall 200 and the ring platform 300 for tensioning the steel wire rope. The packing frame 421 is composed of two layers of horizontal trusses.

[0075] The annular mesh device 400 can ensure the filtration effect while reducing the cost of the mesh device 400. At the same time, the mesh device 400 is assembled from multiple mesh devices 400, which can be assembled according to different construction requirements, making it simple and practical.

[0076] A mud-water separation channel 410 is formed on the packing frame 421. The mud-water separation channel 410 forms an angle with the vertical direction. In some embodiments of this application, the packing frame 421 is provided with a plurality of inclined tubes, which constitute the mud-water separation channel 410. In other embodiments of this application, the packing frame 421 is provided with a plurality of parallel inclined plates 422, and the aforementioned mud-water separation channel 410 is formed between adjacent inclined plates 422. In this embodiment, the inclined plate 422 can be a flat plate or a corrugated plate.

[0077] Due to the limitations of the grid device 400, the Reynolds number of the wastewater flow decreases as it flows through the grid device 400 to the effluent tank 340, reducing turbulence and flow velocity, making it less likely for floc particles to be broken up, and resulting in a more uniform water distribution. Furthermore, the grid device 400 has an inclined sludge-water separation channel 410, which minimizes the influence of horizontal forces on floc particles sliding down into the tank, leading to more stable and effective sedimentation. The grid device 400's design makes the sludge settling area and sedimentation area relatively independent, reducing the agitation of settled floc particles, lessening the influent load on the grid device 400, improving effluent quality, and extending the cleaning cycle of the grid device 400.

[0078] The top ends of the aforementioned mud-suction part 130 and mud-scraping part 140 are vertically spaced from the grid device 400 to prevent the mud-suction part 130 and mud-scraping part 140 from being interfered with by the grid device 400.

[0079] When this application is in operation, sewage enters the inlet tank 330 through the sewage inlet 331. The sewage flows counterclockwise in the inlet tank 330. Since the bottom of the inlet tank 330 is provided with a water distribution hole 332, as a portion of the sewage enters the water distribution hole 332, it forms the first sewage. The first sewage falls into the tank body, and the other portion of the sewage forms the second sewage and continues to flow counterclockwise until it reaches the water stop plate 333.

[0080] When the first wastewater falls into the pool through the water distribution holes 332, it is obstructed by the baffle plate 430 and the baffle skirt 440. After passing through the baffle plate 430, the first wastewater enters the pool and flows towards the center of the pool. Because the water distribution holes 332 are arranged in a ring, the first wastewater at each location collides at the center of the pool, causing it to deflect back towards the grid device 400. During the flow and deflection of the first wastewater towards the center of the pool, the flocculent particles in the sludge are separated and clarified in the settling zone below the grid device 400. The falling flocculent particles settle in the sedimentation zone below the settling zone, forming sludge.

[0081] During the initial wastewater recirculation, the wastewater falls below the grid device 400400, but a portion still acts on the guide plate 500317. The guide plate 500317 mitigates the impact of the wastewater and allows it to fall into the tank. Clearly, the recirculation increases the flow path, making it easier for the flocculent particles within the wastewater to separate. The flocculent particles settle and form sludge, completing the first sedimentation of the wastewater. As the wastewater falls into the tank, the liquid level gradually increases. Passing through the grid device 400400, the wastewater undergoes a second sedimentation process, separating the sludge and water. After this second sedimentation, the wastewater becomes clear water. This clear water flows upwards through the grid device 400400 into the storage area. Once the storage area is full, the clear water overflows from the top of the second enclosure plate 320 and flows into the outlet trough 340. The clear water in the outlet trough 340 is discharged through the clear water outlet 341.

[0082] Based on the design and layout of this application, the first wastewater can flow along the flow path S of the first wastewater. The effluent flow path designed in this application can solve the problems of sludge runoff in the secondary sedimentation tank and poor effluent effect caused by climate, water quality and quantity changes, sludge nutrient deficiency, excessive ammonia nitrogen, mechanical reasons, deoxygenation and other reasons during operation, and solve the problems of large footprint and low sedimentation load of conventional sedimentation tanks.

[0083] During the clarification and sedimentation process of the first wastewater, the first wastewater includes flocculent particles and scum. The scum is relatively light and floats on the liquid surface inside the ring platform 300. The skimming component 620 rotates around the center of the pool on the liquid surface, thereby sweeping the scum floating on the liquid surface into the scum collection hopper 610 fixed inside the ring platform 300.

[0084] The flocculent particles settle in the sedimentation zone under the influence of gravity to form sludge. The sludge scraping section 140 spreads and evenly distributes the sludge settled on the bottom plate 100. The sludge suction section 130 sucks the spread and concentrated sludge into the sludge discharge channel 110.

[0085] As the second wastewater flows counterclockwise, its flow rate decreases due to the drainage from the water distribution hole 332. When the second wastewater reaches the vicinity of the waterstop plate 333, a scum discharge port is provided at the waterstop plate 333, where the scum is discharged from the inlet trough 330. The scum discharge port and the scum collection hopper 610 are respectively connected to the scum well 630 for temporary storage of scum.

[0086] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A radial flow sedimentation tank with circumferential inlet and outlet, characterized in that, include: A base plate (100) and a pool wall (200) disposed above the base plate (100), the pool wall (200) and the base plate (100) forming a pool body; An annular platform (300) is provided above the inner side of the pool wall (200). A first enclosure plate (310) and a second enclosure plate (320) are arranged sequentially from the outside to the inside on the annular platform (300). A water inlet channel (330) is formed between the first enclosure plate (310) and the pool wall (200). A water outlet channel (340) is formed between the first enclosure plate (310) and the second enclosure plate (320). The first enclosure plate (310) is higher than the second enclosure plate (320). The water inlet channel (330) is connected to a sewage inlet (331). Sewage flows unidirectionally along the water inlet channel (330). A water distribution hole (332) connected to the pool body is provided at the bottom of the water inlet channel (330). The water distribution hole (332) is arranged along the direction of sewage flow. A ring-shaped mesh device (400) is disposed below the outlet trough (340). The mesh device (400) is spaced apart from the pool wall (200) to allow sewage to enter the pool directly. The mesh device (400) has an inclined mud-water separation channel (410). A water guide plate (500) is set on a grid device (400). The upper end of the water guide plate (500) is flush with or higher than the upper end of the second enclosure plate (320). The water guide plate (500), the second enclosure plate (320), and the grid device (400) surround each other to form a water storage area. Sewage enters the water storage area through the mud-water separation channel (410) and forms clear water. The clear water flows into the outlet tank (340). The outlet tank (340) is provided with a clear water outlet (341) for the clear water to flow out.

2. The radial flow sedimentation tank with circumferential inlet and outlet as described in claim 1, characterized in that: The water guide plate (500) is disposed on the side of the grid device (400) near the center. The water guide plate (500) includes a first plate body (510) and a second plate body (520). One end of the first plate body (510) is connected to one end of the second plate body. The included angle between the first plate body (510) and the second plate body (520) is an obtuse angle. The upper end of the first plate body (510) is flush with the upper end of the second enclosure plate (320). The second plate body (520) is fixed on the grid device (400).

3. The radial flow sedimentation tank with circumferential inlet and outlet as described in claim 1 or 2, characterized in that: The bottom plate (100) is provided with a sludge discharge channel (110) and a sludge discharge port (120) connecting the sludge discharge channel (110) and the pool body. The radial flow sedimentation tank with circumferential inlet and outlet also includes a sludge treatment unit, which is located at the center of the bottom plate (100). The sludge treatment unit includes a sludge suction part (130) and a sludge scraping part (140). The sludge suction part (130) and the sludge scraping part (140) revolve around the center of the bottom plate (100). The sludge suction part (130) is connected to the sludge discharge hole, and the sludge scraping part (140) spreads the sludge evenly on the bottom plate (100).

4. The radial flow sedimentation tank with circumferential inlet and outlet as described in claim 3, characterized in that: A water-stop plate (333) is also provided in the water inlet trough (330), and the water-stop plate (333) is located upstream of the sewage inlet (331); The radial flow sedimentation tank with circumferential inlet and outlet also includes a slag collection unit, which includes a slag collection hopper (610) and a slag skimming assembly (620). The slag collection hopper (610) is located inside the ring platform (300). A central column (700) is provided at the center of the base plate (100). The sludge treatment unit and the skimming assembly (620) are rotatably mounted on the central column (700). The skimming assembly (620) pushes the scum floating on the liquid surface into the scum collection hopper (610).

5. The radial flow sedimentation tank with circumferential inlet and outlet as described in claim 4, characterized in that: The slag collection unit also includes a slag well (630) and a slag collection pipe (640). The slag collection pipe (640) connects the slag collection hopper (610) and the slag well (630). An outer wall is provided around the periphery of the pool wall (200). The outer wall and the pool wall (200) form a slag well (630) in the radial direction.

6. The radial flow sedimentation tank with circumferential inlet and outlet as described in claim 1, characterized in that: The grid device (400) includes several grid units (420), which are spliced ​​together to form the grid device (400). The grid device (400) and the ring platform (300) form a first gap in the vertical direction, and a second gap in the horizontal direction with the pool wall (200). A baffle plate (430) is provided in the second gap. The baffle plate (430) is located below the water distribution hole (332). A baffle skirt (440) is provided around the first gap. The baffle skirt (440) is used to prevent sewage from entering the first gap.

7. The radial flow sedimentation tank with circumferential inlet and outlet as described in claim 6, characterized in that: The grid unit (420) includes a packing frame (421), and the packing frame (421) is arranged with inclined tubes or inclined plates (422). When the packing frame (421) contains inclined plates (422), adjacent inclined plates (422) form the mud-water separation channel (410).

8. The radial flow sedimentation tank with circumferential inlet and outlet as described in claim 3, characterized in that: The longitudinal section of the base plate (100) is conical, and a drain port (150) is formed in the center of the base plate (100). The drain port (150) is connected to a drain pipe (160) located below the base plate (100). The mud scraper (140) is attached to the base plate (100) and rotates.

9. The radial flow sedimentation tank with circumferential inlet and outlet as described in claim 3, characterized in that: The top ends of the suction section (130) and the scraper section (140) are vertically spaced from the mesh device (400).

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