Rain sewage overflow self-adaptive grading purification system

Abstract

The invention particularly discloses a rain sewage overflow self-adaptive grading purification system, and relates to the technical field of water environment treatment. The system comprises a sedimentation tank, a filter tank, an adjusting tank and a bioretention tank which are transversely communicated in sequence, the sedimentation tank drives a disc with a brush through a telescopic rod arranged in the sedimentation tank to automatically clean water through holes in the side wall of the sedimentation tank; the filter tank adopts a high-efficiency filter layer formed by carbon particle filter balls and a natural fiber woven mesh; the regulating tank is provided with a floating ball valve and a photosensitive sensor to regulate and control a water outlet, so that day-night differential flow control is realized; the bioretention pond comprises a plant layer, an organic mixed soil layer, a fine sand filtering layer and a coarse sand layer, and pollutants are deeply purified through the synergistic effect of plants, filler and microorganisms. The system can intelligently switch operation modes according to rainfall intensity, duration and day and night time periods, automatically adjust graded purification, solve the problems of easy blockage, poor adaptability, low purification efficiency and the like in the traditional technology, and is suitable for urban combined system pipe network overflow pollution control.

Description

Technical Field

[0001] The present invention relates to the technical field of water environment treatment, in particular to a self-adaptive hierarchical purification system for rainwater and sewage overflow. Background Art

[0002] With rapid urbanization, the hardening rate of urban subsurfaces has increased significantly, causing the rainfall runoff coefficient to surge from a natural 0.3-0.5 to 0.7-0.9. Surface runoff quickly carries large amounts of pollutants (including motor vehicle oil, nitrogen, phosphorus, and other nutrients) directly into rivers. The pollution load of a single rainfall event can reach 3-5 times the daily sewage discharge, making it a major cause of black and smelly urban rivers.

[0003] Although major cities have vigorously promoted the separation of rainwater and sewage, due to some factors, the phenomenon of "combining rainwater and sewage" is still widespread.

[0004] The volume and quality of overflow sewage are subject to sudden changes, with an instantaneous increase of 10-20 times during heavy rains. The composition of overflow pollutants is complex, including mixed pollution of suspended, colloidal and dissolved states. Direct discharge into natural water bodies will cause ecological damage such as decreased transparency, eutrophication of water bodies, and death of aquatic organisms. It may even produce harmful substances such as hydrogen sulfide and ammonia, forming black and smelly water bodies. Today's overflow treatment technologies mostly use chemical methods, which have high costs for adding chemicals and are prone to secondary pollution. Some treatment systems cannot effectively cope with the dual fluctuations in water quality and quantity. Therefore, there is an urgent need for an overflow sewage purification system that is efficient, economical, stable, low-energy-consuming and can adapt to flow changes. Summary of the Invention

[0005] The purpose of the present invention is to propose an adaptive graded purification system for rainwater and sewage overflow, which aims to solve the problem of natural water pollution caused by urban overflow. It can adapt to water volume fluctuations, prevent blockage and perform graded deep purification, thereby achieving low energy consumption and high efficiency overflow pollution control.

[0006] To achieve the above-mentioned object, the present invention proposes an adaptive hierarchical purification system for rainwater and sewage overflow, comprising a sedimentation tank, a filtration tank, a regulating tank and a biological retention tank which are sequentially connected transversely; The sedimentation tank is a cylindrical structure with a detachable filter screen on the top, water holes evenly distributed on the side walls, and a funnel-shaped bottom connected to the sewage pipe. The filter pool surrounds the sedimentation tank, and is filled with carbon particle filter balls. The carbon particle filter balls are woven into a mesh with natural fibers to form a filter layer. An overflow pipe is provided on the right side of the filter pool slightly below the top. The regulating tank is lower than the overflow pipe, and a water hole is provided at the connection with the filter tank, which is connected to the outer wall of the sedimentation tank. A drain port 1 is provided at the bottom of the side away from the filter tank, and a drain port 2 is provided above the drain port 1. The biological retention pond is arranged on one side of the regulating pond, and comprises, from top to bottom, a plant layer, an organic mixed soil layer, a fine sand filter layer and a coarse sand layer.

[0007] Preferably, a disc with fine brushes is further provided inside the sedimentation tank, the outer ring of the disc is provided with water holes, and the bottom is connected to the bottom of the tank through a telescopic rod.

[0008] Preferably, the sedimentation tank is located after the overflow well and lower than the overflow well.

[0009] Preferably, the filter pool is lower than the overflow well, higher than the sedimentation tank and has a capped top, and a detachable filter pool cover is provided at the capped top of the filter pool; Preferably, the carbon particle filter ball has a diameter of 20 mm and is wrapped with a natural fiber woven mesh; Preferably, a float valve is installed at the second drain outlet and is connected to a photosensor, and the photosensor will be powered on and started only when the float valve is opened.

[0010] Preferably, the photosensor is located on the ground, and the threshold is greater than or equal to 1000 lux.

[0011] Preferably, the plant layer is planted with reeds, cattails or rushes; the thickness of the organic mixed soil layer is 50-80 cm; the thickness of the fine sand filter layer is 10-30 cm; and the thickness of the coarse sand layer is 20-30 cm.

[0012] Preferably, a drain outlet three is provided slightly above the bottom of the organic mixed soil layer, and the outlet elevation of the drain outlet three is lower than the outlet elevation of the overflow pipe; the drain outlet three and the overflow pipe merge downstream of the biological retention pond and connect to the natural river channel.

[0013] Therefore, the present invention proposes an adaptive hierarchical purification system for rainwater and sewage overflow, which has the following beneficial effects: (1) Green and environmentally friendly: The system does not require the addition of chemical agents and relies on physical and biological effects to achieve sewage treatment; (2) Low maintenance cost: Using natural materials and simple mechanical structure, dynamic cleaning of brush disc combined with washable and replaceable filter balls, the maintenance cycle is extended and the maintenance cost is reduced; (3) Intelligent control: The drainage outlet with dual control of light control and water level can match different sewage treatment systems under different rainfall conditions and perform graded purification, which can well adapt to the sudden changes in overflow water volume and water quality; (4) Eco-friendly: The bioretention pond further purifies water quality and improves the ecological environment through the synergistic effect of plants and fillers.

[0014] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a structural schematic diagram of a rainwater and sewage overflow adaptive graded purification system according to the present invention; Figure 2 This is a schematic diagram of the structure of the disc and peripheral brushes in the sedimentation tank of the present invention; Figure 3 It is a structural schematic diagram of the sedimentation tank wall of the present invention; Figure 4 Schematic diagram of the cross-sectional structure of the filter tank of the present invention; Figure 5 Schematic diagram of the top view of the sedimentation tank and the filtration tank of the present invention; Figure 6 This is a structural diagram of the floating ball valve and the photosensor in the regulating pool in the present invention, which are linked to control the drain outlet 2; Figure 7 Schematic diagram of the structure of the biological retention pond of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 1. Filter screen; 2. Disc; 3. Brush; 4. Telescopic rod; 5. Drain pipe; 6. Carbon particle filter ball; 7. Overflow pipe; 8. Drain outlet one; 9. Drain outlet two; 10. Organic mixed soil layer; 11. Fine sand filter layer; 12. Coarse sand layer; 13. Drain outlet three; 14. Filter tank cover; 15. Float valve; 16. Photosensitive sensor; a. Sedimentation tank; b. Filter tank; c. Equalization tank; d. Bioretention tank. DETAILED DESCRIPTION

[0017] To make the technical solutions, advantages, and objectives of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The described embodiments are part of the embodiments of the present invention, not all of them. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Unless otherwise defined, technical or scientific terms used in the present invention shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0019] like Figure 1-3The figure shows an adaptive graded purification system for rainwater and sewage overflows according to the present invention. It is located after the overflow well and before the drain outlet and comprises a sedimentation tank a, a filtration tank b, a regulating tank c, and a bioretention tank d, which are interconnected in a sequential manner. Sedimentation tank a is equipped with a removable filter screen 1 above it. Inside, a circular disc 2 with a fine brush 3 on its outer edge is located. The outer ring of disc 2 is provided with water holes and is connected to the bottom of the tank via a telescopic rod 4. The bottom of the tank is funnel-shaped and connected to a sewage pipe 5. Multiple small water holes are evenly distributed on the wall of sedimentation tank a.

[0020] like Figure 4-5 As shown, filter tank b surrounds sedimentation tank a and contains carbon granular filter balls 6 wrapped in a natural fiber mesh. Natural fibers are woven between the carbon granular filter balls 6 to form a mesh structure, forming a filter layer. A removable filter tank cover 14 is located on the top of filter tank b, and an overflow pipe 7 is located on the right side of the tank wall, slightly below the top.

[0021] like Figure 6 As shown, a drain outlet 1 8 is provided at the bottom right side of the regulating tank c, and a drain outlet 2 9 is provided above the drain outlet 1 8. A float valve 15 is provided at the drain outlet 2 9 and is connected to a photosensor 16. The float valve 15 controls the connectivity of the circuit of the photosensor 16, and the photosensor 16 controls the opening and closing of the drain outlet 2 9.

[0022] like Figure 7 As shown, bioretention pond d comprises, from top to bottom, a plant layer, an organic mixed soil layer 10 (50-80 cm), a fine sand filter layer 11 (10-30 cm), and a coarse sand layer 12 (20-30 cm). Drain outlet 3 13 is located on the wall of organic mixed soil layer 10. The outlet elevation of drain outlet 3 13 is lower than that of overflow pipe 7. The two drain outlets merge downstream of bioretention pond d and flow into the natural river.

[0023] Working Principle: Sewage from the overflow well first enters sedimentation tank a, where it undergoes preliminary filtration through a removable filter screen 1, intercepting large debris such as branches and leaves. Debris in filter screen 1 can be removed and cleaned periodically. Sewage treated by filter screen 1 enters sedimentation tank a. Water flows through the holes in a circular disc 2 within the tank, where it settles. Sludge settles to a funnel-shaped structure at the bottom and is discharged through a drain pipe 5. Driven by the impact of the water flow, disc 2 and brush 3 move up and down via a telescopic rod 4 to automatically clean the holes in the outer wall of sedimentation tank a, preventing them from clogging and ensuring smooth flow of sewage. Sewage then flows through small holes in the side wall into filter tank b, located outside sedimentation tank a. In filter tank b, the surface fibers of carbon granular filter balls 6 intercept suspended solids, while the micropores of the biochar absorb dissolved pollutants such as COD and ammonia nitrogen. Nitrifying bacteria attached to the fiber surfaces degrade organic nitrogen. Small holes are provided at the connection between filter tank b and regulating tank c, allowing sewage to enter regulating tank c through these holes. Excess sewage is discharged through overflow pipe 7. Regulating tank c serves as a water storage system. Drain outlet 2 (9) on its right wall is dually controlled by light and water level. A float valve (15) controls the power supply to photosensor (16), which in turn controls the opening and closing of drain outlet 2 (9). The threshold of photosensor (16) is set to 1000 lux or higher. When the ambient light intensity is 1000 lux or higher, the energized photosensor activates drain outlet 2 (9), allowing wastewater to enter the bioretention tank simultaneously through drain outlets (18) and (29) for deep purification. This ensures efficient treatment during daytime periods of high wastewater loads. At night, when wastewater loads are lower, the photosensor is deactivated, reducing energy consumption and achieving rapid drainage. Bioretention tank d further removes pollutants through plant absorption, filler adsorption, and microbial degradation, before discharging into the natural waterway through drain outlet 3 (13) on the tank wall. The outlet elevation of drain pipe 3 (13) is lower than that of overflow pipe 7, and the two pipes merge downstream of bioretention tank d and connect to the natural river. The entire process is chemical-free, making it environmentally friendly.

[0024] Example 1 During short, intense daytime rainfall, pipe flow surges, overflows increase, and pollutant concentrations rise. During peak water use during the day, rainwater and domestic sewage mix, leading to chemical oxygen demand (COD) concentrations exceeding 200 mg / L and biochemical oxygen demand (BOD5) concentrations typically ranging from 100 to 200 mg / L. Suspended solids (SS) concentrations can reach 500 to 1000 mg / L during the initial stages of rainfall, and total phosphorus (TP) concentrations can reach 2 to 6 mg / L. Overflows at these times can significantly pollute the aquatic environment, requiring extensive purification before discharge. In this context, the adaptive, graded rainwater overflow purification system adjusts the water level in tank c, causing float valve 15 to rise and energizing photosensor 16. When daytime light intensity is greater than or equal to 1000 lux, photosensor 16 activates drain outlet 29. At this time, the overflow enters the biological retention tank d through the drain outlet 1 8 and the drain outlet 2 9. The amount of water entering the biological retention tank d increases, so that a large amount of overflow with high pollution load concentration is deeply purified through the biological retention tank d before being discharged, which can achieve the coordination of efficient purification and emergency discharge, and the dual-channel drainage volume is adaptively adjusted to ensure treatment efficiency.

[0025] Example 2 In the case of short-duration heavy rainfall at night, rainwater accounts for more than 80%, human activities decrease at night, and the proportion of sewage is small. However, the pollutant concentration load is high in the initial stage of rainfall, and the chemical oxygen demand (COD) may reach 300-800 mg / L, and the suspended solids (SS) reaches 500-1000 mg / L. This part of the overflow needs to be deeply treated. The later overflow is diluted by a large amount of rainwater, and the chemical oxygen demand (COD) is less than 50 mg / L and the suspended solids (SS) is less than 60 mg / L. The pollutant concentration load of the overflow sewage is extremely low, so most of the overflow sewage can be discharged directly. In this context, the rainwater overflow adaptive graded purification system, the water level in the regulating tank c is at or above the drain outlet 2 9, the float valve 15 floats up, and the photosensor 16 is energized. Because at night, the light intensity is less than 1000 lux, the photosensor 16 is not turned on, the drain outlet 2 9 is closed, and the part with higher overflow pollution load enters the biological retention tank d through the drain outlet 1 8 for deep purification treatment and is discharged through the drain outlet 3 13. The remaining majority of the cleaner overflow is discharged through the overflow pipe 7, achieving intelligent staged treatment, full treatment of the initial rain pollution stage, and direct discharge of low-pollution rainwater in the later stage, reducing energy consumption, closing the drain outlet 2 9 to reduce the treatment demand of the biological pool, matching the low microbial activity at night.

[0026] Example 3 During long, low-intensity daytime rainfall, sewage accounts for a high proportion, while rainwater accounts for a low proportion. Pollutant concentrations at the beginning of the rainfall period can even be many times higher than those in domestic sewage, and ammonia nitrogen and total phosphorus may significantly exceed standards. Due to the continued dilution of rainfall, pollutant concentrations decrease compared to the initial stage, but still remain high. Chemical oxygen demand (COD) concentrations may range from 100 to 400 mg / L, and suspended solids (SS) particulate matter may reach high concentrations due to continuous erosion. At this time, the rainwater overflow adaptive graded purification system, regulating tank c, remains at a low water level. The water level in regulating tank c is unable to raise float valve 15, photosensor 16 closes, and outlet 2 9 closes. The entire overflow flows through outlet 1 8 into bioretention tank d for deep purification before being discharged into the natural river through outlet 3 13, achieving stable and continuous operation, adapted to continuous urban rainfall scenarios and providing full deep purification.

[0027] Example 4 Under the conditions of long-duration and low-intensity rainfall at night, human activities are reduced at night and the proportion of rainwater is high, but the pollutant concentration is still high at the initial stage of rainfall. Unlike Example 3, as the duration is extended, the rainfall is continuously diluted, the pollutant concentration is reduced compared with the initial stage, and the pollution load in the water is at a low level. At this time, the rainwater overflow adaptive graded purification system, regulating tank c, the continuous low water level, the float valve 15 in the regulating tank c cannot float completely, the photosensor 16 is closed, the drain outlet 2 9 is closed, and all overflows enter the biological retention tank d through the drain outlet 1 8 for deep purification, and are discharged from the drain outlet 3 13, achieving ultra-low energy consumption operation while deeply purifying.

[0028] It is worth noting that the contents not elaborated in detail in the present invention are all prior art and are well known to those skilled in the art.

[0029] Therefore, the present invention provides an adaptive graded purification system for rainwater and sewage overflow, which has the characteristics of green environmental protection, low maintenance cost, intelligent regulation and eco-friendliness. It can effectively solve the water pollution problem caused by urban overflow and achieve low energy consumption and high efficiency overflow pollution control.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An adaptive hierarchical purification system for rainwater and sewage overflow, characterized in that: It includes sedimentation tanks, filtration tanks, regulating tanks and biological retention tanks that are connected in sequence; The sedimentation tank is a cylindrical structure with a detachable filter screen on the top, water holes evenly distributed on the side walls, and a funnel-shaped bottom connected to the sewage pipe. The filter pool surrounds the sedimentation tank, and is filled with carbon particle filter balls. The carbon particle filter balls are woven into a mesh with natural fibers to form a filter layer. An overflow pipe is provided on the right side of the filter pool slightly below the top. The regulating tank is lower than the overflow pipe, and a water hole is provided at the connection with the filter tank, which is connected to the outer wall of the sedimentation tank. A drain port 1 is provided at the bottom of the side away from the filter tank, and a drain port 2 is provided above the drain port 1. The biological retention pond is arranged on one side of the regulating pond, and comprises, from top to bottom, a plant layer, an organic mixed soil layer, a fine sand filter layer and a coarse sand layer.

2. The adaptive hierarchical purification system for rainwater and sewage overflow according to claim 1, characterized in that: A disc with fine brushes is also provided inside the sedimentation tank. The outer ring of the disc is provided with water holes, and the bottom is connected to the bottom of the tank through a telescopic rod.

3. The adaptive hierarchical purification system for rainwater and sewage overflow according to claim 1, characterized in that: The sedimentation tank is located behind the overflow well and is lower than the overflow well.

4. The adaptive hierarchical purification system for rainwater and sewage overflow according to claim 1, characterized in that: The filter pool is lower than the overflow well, higher than the sedimentation tank and has a capped top. A detachable filter pool cover is provided at the capped top of the filter pool.

5. The adaptive hierarchical purification system for rainwater and sewage overflow according to claim 1, characterized in that: The carbon particle filter ball has a diameter of 20 mm and is wrapped by a natural fiber woven mesh.

6. The self-adaptive hierarchical purification system for rainwater and sewage overflow according to claim 1, characterized in that: A float valve is installed at the second drain outlet and is connected to a photosensitive sensor. The photosensitive sensor will be powered on and started only when the float valve is opened.

7. The self-adaptive graded purification system for rainwater and sewage overflow according to claim 6, characterized in that: The photosensor is located on the ground, and the threshold value is greater than or equal to 1000 lux.

8. The self-adaptive hierarchical purification system for rainwater and sewage overflow according to claim 1, characterized in that: The plant layer is planted with reeds, cattails or rushes; the thickness of the organic mixed soil layer is 50-80 cm; the thickness of the fine sand filter layer is 10-30 cm; and the thickness of the coarse sand layer is 20-30 cm.

9. The self-adaptive graded purification system for rainwater and sewage overflow according to claim 8, characterized in that: A drainage outlet three is provided slightly above the bottom of the organic mixed soil layer, and the outlet elevation of the drainage outlet three is lower than the outlet elevation of the overflow pipe; the drainage outlet three and the overflow pipe merge downstream of the biological retention pond and connect to the natural river channel.

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