Urban road rainwater purification system and method suitable for short-time heavy rainfall

Abstract

The application relates to the technical field of urban construction, and discloses a city road rainwater purification system and method suitable for short-time heavy rain, which comprises a curb, a pre-sedimentation tank, a pretreatment tank, a percolation tank, a green belt detention tank and a rainwater well. Rainwater after being settled in the pre-sedimentation tank flows out from a second overflow port to the pretreatment tank, enters a tree pool seepage layer located at the lowermost layer of the percolation tank, is filtered from the bottom to the top through each layer in the percolation tank, flows out from a third overflow port to the green belt detention tank, and finally flows out from a fourth overflow port to the rainwater well. The fourth overflow port is higher than the third overflow port, and the third overflow port is higher than the second overflow port. Even in the face of short-time heavy rain, the rainwater can only flow out of the rainwater well after being fully filtered through each layer in the percolation tank under the multi-layer filtering structure and the multi-stage height difference elevation position relationship from the bottom to the top, and the purification effect is good. In addition, the filtered rainwater from the bottom to the top has a slow flow rate, small impact on the surface of the percolation tank, and can reduce water and soil loss.

Description

Technical Field

[0001] This application relates to the field of urban construction technology, and in particular to an urban road rainwater purification system and method applicable to short-term heavy rainfall. Background Technology

[0002] With the advancement of urbanization, the paved area of ​​urban roads has surged. This results in large volumes of rainwater runoff, high flow rates, and significant pollution. Direct discharge of rainwater not only exacerbates the burden on urban drainage systems, causing blockages, but also pollutes natural water bodies. Particularly during periods of heavy, short-duration rainfall, the failure to effectively manage rainwater can lead to severe drainage system blockages and pollution problems.

[0003] Existing urban road stormwater purification systems primarily utilize sponge city facilities such as tree pits or green belts to regulate and purify rainwater. For example, Chinese patent document CN215856984U discloses a median strip construction system for road stormwater purification in northern coastal saline-alkali areas, including a median strip green space, a rainwater diversion device, curb stones and their openings, a filler buffer trough, elevated tree pits in the median strip, and an anti-clogging overflow outlet. However, its median strip green space only buffers and filters pollutants from rainwater through a top-down layer of plants, soil, filler, and artificial aquifers. During short-term heavy rainfall, the rainwater flow surges and the velocity is extremely fast, easily causing the system to reach a state of instantaneous overload. This results in rainwater overflowing directly without filtration, leading to poor purification effects. Summary of the Invention

[0004] The purpose of this application is to provide a rainwater purification system and method for urban roads that is suitable for short-term heavy rainfall. This system and method can effectively filter rainwater and achieve good purification results.

[0005] To achieve the above objectives, this application provides an urban road rainwater purification system suitable for short-term heavy rainfall, comprising: The curbstone is set between the roadway and the sidewalk, and it has a first overflow outlet for rainwater collected in the roadway to flow out. A pre-sedimentation tank is used to settle pollutants and temporarily store rainwater. Its inlet is connected to the first overflow outlet, and a second overflow outlet is provided for the settled rainwater to flow out. The pretreatment tank has its inlet connected to the second overflow outlet; The infiltration pond includes a tree pit planting soil layer, a tree pit filter layer, and a tree pit infiltration storage layer arranged sequentially from top to bottom. The pretreatment pond is located above the tree pit infiltration storage layer, and the outlet of the pretreatment pond is connected to the tree pit infiltration storage layer. The pretreatment pond is located on one side of the tree pit planting soil layer and the tree pit filter layer and is not connected to the tree pit planting soil layer and the tree pit filter layer. A third overflow outlet is provided above the tree pit planting soil layer. Rainwater enters the tree pit infiltration storage layer of the infiltration pond through the pretreatment pond, and is filtered from bottom to top through the tree pit infiltration storage layer, the tree pit filter layer, and the tree pit planting soil layer before flowing out from the third overflow outlet. The green belt retention pond has its inlet end connected to the third overflow outlet and is equipped with a fourth overflow outlet for rainwater to flow out. The rainwater well is used to discharge rainwater into the municipal drainage system, and the rainwater well is connected to the green belt retention pond through the fourth overflow outlet; The fourth overflow port is higher than the third overflow port, and the third overflow port is higher than the second overflow port.

[0006] Furthermore, the green belt retention pond includes a green belt planting layer, a green belt filter layer, a filter transition layer and a green belt infiltration layer arranged sequentially from top to bottom. Rainwater passes through the green belt planting layer, the green belt filter layer and the filter transition layer sequentially from top to bottom before entering the green belt infiltration layer for storage.

[0007] Furthermore, the fourth overflow outlet is 2-8 cm higher than the third overflow outlet to prevent rainwater from flowing into the green belt retention pond from the third overflow outlet and then directly overflowing and being discharged.

[0008] Furthermore, the fourth overflow outlet is located 5-15cm above the planting layer of the green belt; the third overflow outlet is located 3-10cm above the planting soil layer of the tree pit, so that short-term water accumulation forms on the surface of both the green belt retention pond and the infiltration pond, thereby slowing down the rainwater flow rate.

[0009] Furthermore, the thickness of the green belt filter layer ranges from 20 to 40 cm, and it is used to provide a growth medium for the plant roots of the green belt planting layer.

[0010] Furthermore, the particles in the green belt infiltration layer are larger than those in the green belt filter layer; the thickness of the filter transition layer ranges from 5 to 10 cm to prevent fine particles from the green belt filter layer from being carried into the green belt infiltration layer.

[0011] Furthermore, the second overflow outlet is located above the pre-sedimentation tank to allow rainwater to settle sufficiently.

[0012] Furthermore, a filter screen is installed at the fourth overflow outlet to filter out floating debris and prevent it from clogging the rainwater well.

[0013] Furthermore, a screen is installed above the pre-sedimentation tank to intercept waste.

[0014] A method for purifying urban road rainwater suitable for short-term heavy rainfall, based on any one of the urban road rainwater purification systems described above, wherein the equipment includes: S1. Rainwater in the roadway is collected and flows into the pre-sedimentation tank through the first overflow outlet. S2. Rainwater settles in the pre-sedimentation tank and flows into the pretreatment tank through the second overflow outlet; S3. Rainwater flows into the pretreatment tank, where the flow rate slows down, and then enters the tree pit infiltration layer of the infiltration tank. S4. Rainwater is filtered from bottom to top in the infiltration pond through the tree pit infiltration layer, the tree pit filter layer and the tree pit planting soil layer, and then flows out through the third overflow outlet to the green belt retention pond. S5. Rainwater is filtered in the green belt retention pond, flows out through the fourth overflow outlet to the rainwater well and is discharged into the municipal drainage system. S6. After the rainfall ends, inspect and clean the first overflow outlet, the second overflow outlet, the third overflow outlet, the fourth overflow outlet, the pre-sedimentation tank, and the pretreatment tank.

[0015] Compared with the prior art, the urban road rainwater purification system applicable to short-term heavy rainfall in this application embodiment has the following advantages: The inlet of the pretreatment tank in this application is connected to the second overflow outlet of the pre-sedimentation tank, and the outlet is connected to the tree pit infiltration layer. After settling in the pre-sedimentation tank, the rainwater flows out from the second overflow outlet into the pretreatment tank, where the flow rate slows down. Then, the rainwater enters the tree pit infiltration layer located at the bottom of the infiltration tank from the pretreatment tank. From bottom to top, it is filtered through the tree pit infiltration layer, the tree pit filtration layer, and the tree pit planting soil layer, and then flows out through the third overflow outlet into the green belt retention tank. Finally, it flows out through the fourth overflow outlet into the rainwater well and is discharged into the municipal drainage system. After pretreatment in the pretreatment tank, rainwater is filtered through each layer of the infiltration tank from bottom to top. The fourth overflow outlet is higher than the third overflow outlet, and the third overflow outlet is higher than the second overflow outlet. This creates a progressive elevation difference in the water flow through the pre-sedimentation tank, pretreatment tank, infiltration tank, and green belt retention tank. This forms a system capable of storing large amounts of water in a short time and effectively filtering rainwater. Even in the face of short-term heavy rainfall, the multi-layered filtration structure and the multi-level elevation difference ensure that rainwater is fully filtered through each layer of the infiltration tank before flowing into the rainwater well. It does not overflow directly into the rainwater well unfiltered, resulting in good purification and preventing pollutants from clogging the well. Furthermore, the slow flow of filtered rainwater from bottom to top minimizes the impact on the planting soil layer in the tree pits, reducing soil erosion. Attached Figure Description

[0016] Figure 1 This is a plan view of the urban road rainwater purification system according to an embodiment of this application.

[0017] Figure 2 This is a cross-sectional schematic diagram of the urban road rainwater purification system according to an embodiment of this application.

[0018] Figure 3 This is a flowchart of rainwater purification in an embodiment of this application.

[0019] In the diagram, 1. Driveway; 11. Curbstone; 12. First overflow outlet; 2. Pre-sedimentation tank; 21. Second overflow outlet; 22. Bar screen; 3. Pretreatment tank; 4. Infiltration tank; 41. Tree pit planting soil layer; 42. Tree pit filter layer; 43. Tree pit infiltration storage layer; 44. Third overflow outlet; 5. Green belt retention tank; 51. Green belt planting layer; 52. Green belt filter layer; 53. Filter transition layer; 54. Green belt infiltration storage layer; 55. Fourth overflow outlet; 6. Rainwater well. Detailed Implementation

[0020] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0021] The directions such as front, back, left, and right mentioned in this article are defined relative to the directions in the various accompanying figures. They are relative concepts and therefore can change depending on their different positions and practical applications. Therefore, these or other directions should not be interpreted as restrictive terms.

[0022] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0023] like Figure 1 , Figure 2 As shown in the illustration, an urban road rainwater purification system according to an embodiment of this application includes a curbstone 11, a pre-sedimentation tank 2, a pretreatment tank 3, an infiltration tank 4, a green belt retention tank 5, and a rainwater well 6. The curbstone 11 is positioned between the roadway 1 and the sidewalk, blocking the roadway 1 and preventing rainwater from flowing into the sidewalk. The curbstone 11 has a first overflow outlet 12, and the inlet of the pre-sedimentation tank 2 is connected to the first overflow outlet 12. Rainwater on the roadway 1 collects at the first overflow outlet 12 and flows out into the pre-sedimentation tank 2, where pollutants are temporarily settled. The upper part of the pre-sedimentation tank 2 has a second overflow outlet 21, and the inlet of the pretreatment tank 3 is connected to the second overflow outlet 21. After sufficient settling in the pre-sedimentation tank 2, the rainwater flows out of the pretreatment tank 3 through the second overflow outlet 21, where the flow rate slows down, and then enters the infiltration tank 4 from the pretreatment tank 3.

[0024] The infiltration pond 4 includes, from top to bottom, a tree pit planting soil layer 41, a tree pit filter layer 42, and a tree pit infiltration storage layer 43. A pretreatment pond 3 is located above the tree pit infiltration storage layer 43, situated on one side of the tree pit planting soil layer 41 and the tree pit filter layer 42, but not connected to them. The outlet of the pretreatment pond 3 is connected to the tree pit infiltration storage layer 43, the lowest layer of the infiltration pond 4. Rainwater enters the tree pit infiltration storage layer 43 from the pretreatment pond 3 and is filtered sequentially from bottom to top through the tree pit infiltration storage layer 43, the tree pit filter layer 42, and the tree pit planting soil layer 41. A third overflow outlet 44 is located above the tree pit planting soil layer 41, and the inlet of the green belt retention pond 5 is connected to the third overflow outlet 44. Rainwater filtered by the infiltration pond 4 flows out from the third overflow outlet 44 into the green belt retention pond 5.

[0025] The greenbelt retention pond 5 comprises, from top to bottom, a greenbelt planting layer 51, a greenbelt filter layer 52, a filter transition layer 53, and a greenbelt infiltration layer 54. Rainwater is filtered sequentially through the greenbelt planting layer 51, the greenbelt filter layer 52, and the filter transition layer 53 before entering the greenbelt infiltration layer 54 for storage. A fourth overflow outlet 55 is located above the greenbelt planting layer 51, and a rainwater well 6 is connected to the greenbelt retention pond 5 through the fourth overflow outlet 55. Rainwater filtered by the greenbelt retention pond 5 flows out from the fourth overflow outlet 55 into the rainwater well 6 and is discharged into the municipal drainage system.

[0026] After pretreatment in the pretreatment pond 3, rainwater is filtered through each layer of the infiltration pond 4 from bottom to top. Even in the face of short-term heavy rainfall, the rainwater can only flow into the rainwater well 6 after being fully filtered through each layer of the infiltration pond 4, thanks to the multi-layer filtration structure from bottom to top. It will not overflow directly into the rainwater well 6 without being filtered, resulting in good purification effect and preventing pollutants from clogging the rainwater well 6. In addition, the slow flow rate of the filtered rainwater from bottom to top minimizes the impact on the planting soil layer 41 of the tree pit, reducing soil erosion.

[0027] The fourth overflow outlet 55 is higher than the third overflow outlet 44, and the third overflow outlet 44 is higher than the second overflow outlet 21. This creates a progressive elevation difference in the water flow through the pre-sedimentation tank 2, pretreatment tank 3, infiltration tank 4, and green belt retention tank 5, thus forming a system that can store a large amount of water in a short time and effectively filter rainwater.

[0028] Preferably, the tree pit planting soil layer 41 of the infiltration pond 4 is used for planting trees. The third overflow outlet 44 is located 3-10 cm above the tree pit planting soil layer 41 and 5-15 cm below the top edge of the side wall of the infiltration pond 4. In this embodiment, the third overflow outlet 44 is located 6 cm above the tree pit planting soil layer 41 and 8 cm below the top edge of the side wall of the infiltration pond 4. This ensures that rainwater filtered by the infiltration pond 4 and rainwater dripping directly onto the surface of the tree pit planting soil layer 41 first forms a short-term water accumulation of 6 cm on the surface of the infiltration pond 4 and completes preliminary infiltration before entering the green belt retention pond 5. This slows down the rainwater flow rate and prevents rainwater from eroding the surface of the tree pit planting soil layer 41 and causing soil erosion. Meanwhile, the fourth overflow outlet 55 is located 5-15cm above the green belt planting layer 51 and 2-8cm higher than the third overflow outlet 44. In this embodiment, the fourth overflow outlet 55 is located 12cm above the green belt planting layer 51 and 6cm higher than the third overflow outlet 44. Rainwater entering the green belt retention tank 5 through the third overflow outlet 44 and rainwater dripping directly onto the surface of the green belt planting layer 51 first form short-term water accumulation on the surface of the green belt retention tank 5. This prevents rainwater from overflowing and being discharged directly without sufficient filtration after flowing into the green belt retention tank 5 from the third overflow outlet 44, thus prolonging the retention and filtration time of rainwater and allowing the rainwater to be fully filtered in the green belt retention tank 5.

[0029] The green belt planting layer 51 is planted with moisture-tolerant plants; the green belt filter layer 52 provides a growth medium for the roots of the plants in the green belt planting layer 51, with a thickness ranging from 20 to 40 cm; the green belt infiltration layer 54 uses large-particle materials such as gravel, pebbles, or graded crushed stone to store infiltrated rainwater, with a thickness ranging from 15 to 30 cm. The particles in the green belt infiltration layer 54 are larger than those in the green belt filter layer 52. A filter transition layer 53 is provided between the green belt infiltration layer 54 and the green belt filter layer 52, with a thickness ranging from 5 to 10 cm, which can prevent fine particles from the green belt filter layer 52 from being carried into the green belt infiltration layer 54.

[0030] Preferably, a debris screen 22 is installed above the pre-sedimentation tank 2. Rainwater flowing out of the first overflow outlet 12 first flows through the debris screen 22, where it intercepts fallen leaves, plastics, and large particles of mud and sand before flowing into the pre-sedimentation tank 2.

[0031] Preferably, both the third overflow outlet 44 and the fourth overflow outlet 55 are equipped with filter screens. The structure of the filter screens includes, but is not limited to, slotted grids, detachable screens, or baffle components. These filter screens can filter floating debris, preventing floating debris such as leaves in the infiltration tank 4 from entering the green belt retention tank 5 through the third overflow outlet 44, and preventing floating debris in the green belt retention tank from entering the rainwater well 6 through the fourth overflow outlet 55 and causing blockage.

[0032] Based on the aforementioned urban road stormwater purification system, this application proposes a method for purifying urban road stormwater, see [link / reference]. Figure 3 This includes the following steps: S1. Rainwater in the driveway 1 is collected and flows into the pre-sedimentation tank 2 through the first overflow outlet 12; S2. Rainwater settles in the pre-sedimentation tank 2 and flows into the pretreatment tank through the second overflow outlet 21. S3. Rainwater flows into the pretreatment tank 3, where the flow rate slows down, and then enters the tree pit infiltration layer 43 of the infiltration tank 4 through the pretreatment tank 3. S4. Rainwater in the infiltration pond 4 is filtered from bottom to top through the tree pool infiltration layer 43, the tree pool filter layer 42 and the tree pool planting soil layer 41, and then flows out through the third overflow outlet 44 to the green belt retention pond 5. S5. Rainwater is filtered in the green belt retention pond 5, flows out through the fourth overflow outlet 55 to the rainwater well 6 and is discharged into the municipal drainage system. S6. After the rainfall ends, inspect and clean the first overflow outlet 12, the second overflow outlet 21, the third overflow outlet 44, the fourth overflow outlet 55, the pre-sedimentation tank 2, and the pretreatment tank 3.

[0033] Rainwater undergoes sedimentation in the pre-sedimentation tank 2, where denser particles such as silt settle before entering the pretreatment tank 3, preventing garbage from entering and causing blockages. After pretreatment in the pretreatment tank 3, the rainwater is filtered from bottom to top through the tree pit infiltration layer 43, the tree pit filter layer 42, and the tree pit planting soil layer 41 within the infiltration tank 4. Even in the face of short-term heavy rainfall, the rainwater, thanks to the multi-layered filtration structure from bottom to top, can only flow out of the rainwater well 6 after being fully filtered by each layer within the infiltration tank 4. It will not overflow directly into the rainwater well 6 without filtration, resulting in good purification and preventing pollutants from clogging the rainwater well 6.

[0034] Preferably, in step S1, when it rains, the rainwater on the roadway 1 collects at the first overflow outlet 12. After flowing out of the first overflow outlet 12, it first flows through the debris barrier 22, which intercepts fallen leaves, plastics and large particles of mud and sand, and then flows into the pre-sedimentation tank 2.

[0035] In summary, this application provides an urban road rainwater purification system. The inlet of the pretreatment tank 3 is connected to the second overflow port 21 of the pre-sedimentation tank 2, and the outlet is connected to the tree pit infiltration layer 43 located at the bottom of the infiltration tank 4. After settling in the pre-sedimentation tank 2, the rainwater flows out from the second overflow port 21 into the pretreatment tank 3, where the flow rate slows down. Then, it enters the tree pit infiltration layer 43 located at the bottom of the infiltration tank 4 from the pretreatment tank 3. From bottom to top, it is filtered through the tree pit infiltration layer 43, the tree pit filter layer 42, and the tree pit planting soil layer 41, and flows out through the third overflow port 44 into the green belt retention tank 5. Finally, it flows out through the fourth overflow port 55 into the rainwater well 6 and is discharged into the municipal drainage system. After pretreatment in the pretreatment tank 3, rainwater is filtered from bottom to top through each layer of the infiltration tank 4. The fourth overflow outlet 55 is higher than the third overflow outlet 44, and the third overflow outlet 44 is higher than the second overflow outlet 21. This creates a progressive elevation difference in the water flow through the pre-sedimentation tank 2, pretreatment tank 3, infiltration tank 4, and green belt retention tank 5. This forms a system capable of storing large amounts of water in a short time and effectively filtering rainwater. Even in the face of short-term heavy rainfall, the rainwater, due to the multi-layered filtration structure and the multi-level elevation difference, can only flow into the rainwater well 6 after being fully filtered through each layer of the infiltration tank 4. It will not overflow directly into the rainwater well 6 unfiltered, resulting in good purification and preventing pollutants from clogging the rainwater well 6. Furthermore, the slow flow of filtered rainwater from bottom to top minimizes the impact on the planting soil layer 41 of the tree pit, reducing soil erosion.

[0036] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this application, and these improvements and substitutions should also be considered within the scope of protection of this application.

Claims

1. A rainwater purification system for urban roads suitable for short-term heavy rainfall, characterized in that: include: The curbstone is set between the roadway and the sidewalk, and it has a first overflow outlet for rainwater collected in the roadway to flow out. A pre-sedimentation tank is used to settle pollutants and temporarily store rainwater. Its inlet is connected to the first overflow outlet, and a second overflow outlet is provided for the settled rainwater to flow out. The pretreatment tank has its inlet connected to the second overflow outlet; The infiltration pond includes a tree pit planting soil layer, a tree pit filter layer, and a tree pit infiltration storage layer arranged sequentially from top to bottom. The pretreatment pond is located above the tree pit infiltration storage layer, and the outlet of the pretreatment pond is connected to the tree pit infiltration storage layer. The pretreatment pond is located on one side of the tree pit planting soil layer and the tree pit filter layer and is not connected to the tree pit planting soil layer and the tree pit filter layer. A third overflow outlet is provided above the tree pit planting soil layer. Rainwater enters the tree pit infiltration storage layer of the infiltration pond through the pretreatment pond, and is filtered from bottom to top through the tree pit infiltration storage layer, the tree pit filter layer, and the tree pit planting soil layer before flowing out from the third overflow outlet. The green belt retention pond has its inlet end connected to the third overflow outlet and is equipped with a fourth overflow outlet for rainwater to flow out. The rainwater well is used to discharge rainwater into the municipal drainage system, and the rainwater well is connected to the green belt retention pond through the fourth overflow outlet; The fourth overflow port is higher than the third overflow port, and the third overflow port is higher than the second overflow port.

2. The urban road rainwater purification system as described in claim 1, characterized in that: The green belt retention pond includes a green belt planting layer, a green belt filtration layer, a filtration transition layer and a green belt infiltration layer arranged from top to bottom. Rainwater passes through the green belt planting layer, the green belt filtration layer and the filtration transition layer from top to bottom and then enters the green belt infiltration layer for storage.

3. The urban road rainwater purification system as described in claim 2, characterized in that: The fourth overflow outlet is 2-8 cm higher than the third overflow outlet to prevent rainwater from flowing into the green belt retention pond from the third overflow outlet and then overflowing directly.

4. The urban road rainwater purification system as described in claim 3, characterized in that: The fourth overflow outlet is located 5-15cm above the planting layer of the green belt; the third overflow outlet is located 3-10cm above the planting soil layer of the tree pit, so that water accumulates briefly on the surface of both the green belt retention pond and the infiltration pond, thereby slowing down the rainwater flow rate.

5. The urban road rainwater purification system as described in claim 2, characterized in that: The thickness of the green belt filter layer ranges from 20 to 40 cm, and it is used to provide a growth medium for the plant roots of the green belt planting layer.

6. The urban road rainwater purification system as described in claim 5, characterized in that: The particles in the green belt infiltration layer are larger than those in the green belt filter layer; the thickness of the filter transition layer is 5-10 cm to prevent fine particles from the green belt filter layer from being carried into the green belt infiltration layer.

7. The urban road rainwater purification system as described in any one of claims 1-6, characterized in that: The second overflow outlet is located above the pre-sedimentation tank to allow rainwater to settle sufficiently.

8. The urban road rainwater purification system as described in any one of claims 1-6, characterized in that: A filter screen is installed at the fourth overflow outlet to filter out floating debris and prevent it from clogging the rainwater well.

9. The urban road rainwater purification system as described in any one of claims 1-6, characterized in that: A screen is installed above the pre-sedimentation tank to intercept waste.

10. A method for purifying rainwater from urban roads applicable to short-duration heavy rainfall, characterized in that: Based on the urban road stormwater purification system as described in any one of claims 1 to 9, it includes the following steps: S1. Rainwater in the roadway is collected and flows into the pre-sedimentation tank through the first overflow outlet. S2. Rainwater settles in the pre-sedimentation tank and flows into the pretreatment tank through the second overflow outlet; S3. Rainwater flows into the pretreatment tank, where the flow rate slows down, and then enters the tree pit infiltration layer of the infiltration tank. S4. Rainwater is filtered from bottom to top in the infiltration pond through the tree pit infiltration layer, the tree pit filter layer and the tree pit planting soil layer, and then flows out through the third overflow outlet to the green belt retention pond. S5. Rainwater is filtered in the green belt retention pond, flows out through the fourth overflow outlet to the rainwater well and is discharged into the municipal drainage system. S6. After the rainfall ends, inspect and clean the first overflow outlet, the second overflow outlet, the third overflow outlet, the fourth overflow outlet, the pre-sedimentation tank, and the pretreatment tank.

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