A plant rock crushing ecological filter dam

Abstract

The present application belongs to the river water environment treatment field, and discloses a kind of plant rubble ecological filter dam, including dam body, steel wire net, aquatic plant, surface cover layer filler, middle layer filter layer filler, middle-lower layer transition layer filler and bottom drainage layer filler, surface cover layer filler, middle layer filter layer filler, middle-lower layer transition layer filler and bottom drainage layer filler are sequentially arranged from top to bottom in dam body, aquatic plant is planted on the top surface of surface cover layer filler.The present application combines the structural layout and function of vertical subsurface flow artificial wetland and traditional rubble filter dam, forms an ecological landscape device with adsorption, filtration and self-purification capacity, which can effectively improve the self-purification capacity of river, realize resource saving, and better integrate into the environment while playing the role of adsorption and filtration, with good visual effect.

Description

Technical Field

[0001] This invention belongs to the field of river water environment management, and is particularly applicable to plant-gravel ecological filter dams for river water filtration and self-purification. Background Technology

[0002] Intermittent and large-scale dumping of domestic sewage or garbage into rivers has damaged river ecosystems, exceeding their capacity to absorb pollutants, leading to increasingly poor water quality and a decline in self-purification capabilities. River ecological restoration has now become a top priority in environmental issues. Traditional filter dams have a single function, filled with a single type of filler. While simple in composition, they are ineffective in purifying heavily polluted rivers, especially in removing total nitrogen (TN). Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a plant-based gravel ecological filter dam that improves the removal rate of TN.

[0004] This invention, a plant-based gravel ecological filter dam, combines the structural layout and function of vertical subsurface flow constructed wetlands with traditional gravel filter dams. The original mixed gravel filler inside the gravel filter dam is replaced with a layered layout, including a cover layer, a filter media layer, a transition layer, and a drainage layer. Each layer of gravel or crushed stone filler has a different particle size range, and one or more aquatic plants are planted on the filler, forming an ecological landscape device with adsorption, filtration, and self-purification capabilities. This device effectively enhances the self-purification capacity of rivers, prevents resource waste, and while performing adsorption and filtration functions, it also integrates better into the environment, providing a superior aesthetic experience.

[0005] Specifically, the present invention relates to a plant-based gravel ecological filter dam, comprising a dam body, wire mesh, aquatic plants, a surface covering layer filler, a middle filter layer filler, a lower middle transition layer filler, and a bottom drainage layer filler. The dam body is a trough with an open top and has four side walls, namely two long side walls and two short side walls. Water permeable holes are made on the two long side walls, and wire mesh is fixed on the inner wall of the two long side walls. The surface covering layer filler, the middle filter layer filler, the lower middle transition layer filler, and the bottom drainage layer filler are arranged sequentially from top to bottom within the dam body. Aquatic plants are planted on the top surface of the surface covering layer filler.

[0006] The surface covering layer filler is gravel with a particle size of 10mm to 30mm, a thickness of 200mm to 300mm, and a porosity of 45% to 50% after filling;

[0007] The middle filter media layer is a mixture of gravel with a particle size of 2mm to 6mm, macroporous cation exchange resin with a particle size of 1.25mm to 5mm, and camphor wood with a particle size of 2mm to 5mm in a volume ratio of 1:1:1, with a filling thickness of 400mm to 1400mm and a filling porosity of 30% to 35%. This layer of filler has the characteristics of large pore size, large specific surface area, and large adsorption capacity. In addition, the decomposition of camphor wood in water provides a certain amount of carbon source for microorganisms, providing them with a more stable growth environment and greatly reducing the residual sludge production rate of the device. This mixed filler layer, as the core filler layer of the entire device, adsorbs nutrients such as ammonia nitrogen and phosphorus in the water, facilitating aquatic plants to better absorb nitrogen and phosphorus nutrients through their roots, thereby improving the purification efficiency of the device for the river.

[0008] The middle and lower transition layer filler is gravel with a particle size of 5mm to 10mm, a filling thickness of 200mm to 300mm, and a filling porosity of 35% to 45%.

[0009] The bottom drainage layer filler is a mixture of sand and gravel with a particle size of 10mm to 150mm, with a filling thickness of 200mm to 300mm and a filling porosity of 45% to 55%.

[0010] Furthermore, the macroporous cation adsorption resin is pretreated before use. The pretreatment method is as follows: first, wash with water and ethanol in sequence, then rinse with 3% HCl at a rate of 2-3 BV / h, then wash with water until neutral, and finally repeat the previous step with NaOH instead of HCl to complete the pretreatment of the resin.

[0011] Furthermore, the camphor wood needs to be pretreated. The pretreatment method is as follows: water is taken from the polluted river to be treated and used to soak the camphor wood for 120 days, then soaked in a 1% sodium bicarbonate solution for 1-2 hours, cleaned and then soaked in distilled water for later use.

[0012] Furthermore, the aquatic plants are emergent plants suitable for the local temperature and climate, and are planted in combination according to ecological and landscape diversity. The root systems of aquatic plants can absorb pollutants such as C, N, and P from sewage to the maximum extent as a source of nutrients for their own growth, and can be selected according to ecological, artistic, and diversity principles, while taking into account factors such as seasonal climate.

[0013] Furthermore, the permeable hole diameter is 40-60mm, and the hole spacing is 20-40mm; the wire mesh size is 0.5-2mm.

[0014] Plant-gravel ecological filter dams are installed at both ends of the river channel requiring treatment. Their length is determined by the river width, and their height by the water level, ensuring the water level is sufficient for planting aquatic plants. These dams act as interceptors and filters, removing floating debris and large, recalcitrant suspended particles from the untreated section of the water, effectively preventing pollution from flowing into the treated section. Water from the untreated section flows through the dam via permeable holes. The large-pore cationic adsorption resin and camphor wood in the middle filter layer adsorb nutrients such as nitrogen and phosphorus. Aquatic plants then absorb nutrients from the middle filter layer through their roots, using them as nutrients for their own growth. This process achieves resource reuse while effectively adsorbing and degrading pollutants in the water. The camphor wood provides a carbon source for aquatic microorganisms, creating a more stable growth environment. A biofilm forms on the surface of the filter media, further adhering to and degrading pollutants in the water. Based on the principles of ecology, art, and diversity, the aquatic plants are selected and planted in combination according to local seasonal climate and the growth habits of each type, forming a multifunctional ecological landscape.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. This invention combines the structural layout and function of vertical subsurface flow constructed wetlands with traditional gravel filter dams, saving land area.

[0017] 2. This invention uses gravel and crushed stone fillers, which are wear-resistant, corrosion-resistant, and easy to form biofilms. They can effectively filter large particulate pollutants in water, and the biofilm formed by microorganisms on their surface can further degrade pollutants in water.

[0018] 3. This invention utilizes a composite filler consisting of gravel, macroporous cation exchange resin, and camphor wood. This composite filler features large pore size, large specific surface area, and large adsorption capacity. Furthermore, the decomposition of camphor wood in water provides a certain amount of carbon source for microorganisms, offering them a more stable growth environment and significantly reducing the residual sludge generation rate of the device. This composite filler layer serves as the core filler layer in the entire device, adsorbing nutrients such as ammonia nitrogen and phosphorus in the water. This facilitates better absorption of nitrogen and phosphorus nutrients by aquatic plants through their roots, while also increasing the purification efficiency of the device for river channels.

[0019] 4. This invention utilizes aquatic plants, which increases the diversity of river vegetation, improves the river ecosystem, enhances the river's self-purification capacity, and integrates better into the environment, resulting in a better aesthetic effect and significant ecological benefits.

[0020] 5. The principle of this invention is simple and clear, it has multiple environmental protection functions, saves on initial investment, and has significant engineering benefits.

[0021] 6. This invention is particularly suitable for segmented river management, effectively improving the river's self-purification capacity, protecting the treated section from secondary pollution, and resulting in significant environmental benefits. Attached Figure Description

[0022] Figure 1 Top view of a plant-gravel ecological filter dam;

[0023] Figure 2 for Figure 1 AA-direction cross-section view;

[0024] Figure 3 for Figure 1 BB-direction cross-section view.

[0025] The attached figures are labeled as follows:

[0026] 1 is the dam body, 2 is the wire mesh, 3 is the permeable hole, 4 is the aquatic plants, 5 is the surface covering layer filler, 6 is the middle layer filter material filler, 7 is the middle and lower transition layer filler, and 8 is the bottom drainage layer filler. Detailed Implementation

[0027] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0028] The plant-gravel ecological filter dam of the present invention is composed of a dam body 1, wire mesh 2, aquatic plants 4, a surface covering layer filler 5, a middle filter layer filler 6, a middle and lower transition layer filler 7, and a bottom drainage layer filler 8. The dam body 1 is a trough with an open top and has four side walls, namely two long side walls and two short side walls. Water permeable holes 3 are made on the two long side walls, and wire mesh 2 is fixed on the inner wall of the two long side walls. The surface covering layer filler 5, the middle filter layer filler 6, the middle and lower transition layer filler 7, and the bottom drainage layer filler 8 are arranged sequentially from top to bottom inside the dam body 1. Aquatic plants 4 are planted on the top surface of the surface covering layer filler 5.

[0029] The specifications and dimensions of the filter dam need to be designed according to the actual river management project. The dam body 1 is a reinforced concrete structure, typically 200mm thick. Two pieces of wire mesh 2 are welded to the reinforcing steel in the dam structure and installed on the side with permeable holes 3. These meshes are made of fine steel wire woven into a net, with a mesh count of 18 (1.00mm opening). They intercept sand and gravel filler, ensuring they do not leak into the water and cause pollution. The permeable holes 3 have a diameter of 50mm, with a spacing of 30mm between each hole, serving a water distribution function.

[0030] Example 1

[0031] The surface cover layer filler 5 consists of gravel with a particle size of 10mm to 30mm, with a filling thickness of 250mm and a porosity of 45% to 50% after filling.

[0032] The middle layer filter media 6 is a mixture of gravel with a particle size of 2mm to 6mm, macroporous cation adsorption resin with a particle size of 1.25mm, and camphor wood with a particle size of 5mm. The volume ratio of gravel, macroporous cation adsorption resin, and camphor wood is 1:1:1. The filling thickness is 800mm, and the porosity after filling is 30% to 35%.

[0033] A certain amount of river water was sampled from the Dagu sewage discharge river. Camphor wood was soaked in the river water for 120 days, then soaked in a 1% sodium bicarbonate solution for 1 hour. After cleaning, it was soaked in distilled water for later use. The macroporous cation adsorption resin was rinsed twice with deionized water, soaked in 95% ethanol for 24 hours, and rinsed with 95% ethanol until the ethanol flowing out did not show turbidity when water was added. The resin was then rinsed with a large amount of water to remove the ethanol. Next, it was rinsed with 3% HCl at a rate of 2-3 BV / h, and then washed with water until neutral. The previous step was repeated with NaOH instead of HCl. The pretreatment of the resin was then completed.

[0034] The middle and lower transition layer filler 7 consists of gravel with a particle size of 5mm to 10mm, with a filling thickness of 250mm and a porosity of 35% to 45% after filling.

[0035] The bottom drainage layer filler 8 is a mixture of sand and gravel with a particle size of 10mm to 150mm, with a filling thickness of 250mm and a porosity of over 45% after filling.

[0036] After the bottom drainage layer filler 8, the middle and lower transition layer filler 7, the middle filter layer filler 6, and the surface cover layer filler 5 are sequentially filled into the dam body 1, the river water from the Dagu sewage discharge river is added into the dam body. At the same time, calamus is planted in the surface cover layer filler at a planting density of 10 plants / m². 2 They will germinate in about 25 days after planting.

[0037] The main pollutants in the Dagu sewage discharge river were BOD5 11.1 mg / L, COD 21.05 mg / L, TP 3.7 mg / L, and TN 30.2 mg / L. The dam adopted a sequencing batch reactor (SBR) design with a hydraulic retention time of 12 hours. The initial influent volume was 2 L, increasing by 2 L every 3 days until a total of 10 L was reached, at which point further increases were stopped. During reactor operation, the water quality indicators of the influent and effluent were measured. The main pollutants in the effluent were determined using the dilution and inoculation method, dichromate method, ammonium molybdate spectrophotometric method, Sodium's reagent colorimetric method, and alkaline potassium persulfate digestion ultraviolet spectrophotometric method. The results showed that the main pollutants were BOD5 1.31 mg / L, COD 1.01 mg / L, TP 0.2 mg / L, and TN 0.96 mg / L, respectively. The removal rates were 88.2% for BOD5, 95.2% for COD, 94.5% for TP, and 96.83% for TN.

[0038] Comparative Example 1

[0039] The difference from Example 1 is that no large-pore cationic adsorption resin is used. The middle filter layer packing 6 is a mixture of gravel with a particle size of 2mm to 6mm and camphor wood with a particle size of 5mm. The volume ratio of gravel to camphor wood is 1:1, and the packing thickness is 800mm.

[0040] Using the same test method as in Example 1, the removal rates were 585.6% for BOD, 93.7% for COD, 80.7% for TP, and 89.4% for TN.

[0041] Comparative Example 2

[0042] The difference from Example 1 is that camphor wood is not used. The middle filter layer packing 6 is a mixture of gravel with a particle size of 2mm to 6mm and macroporous cation adsorption resin with a particle size of 1.25mm. The volume ratio of gravel to macroporous cation adsorption resin is 1:1, and the packing thickness is 800mm.

[0043] Using the same test method as in Example 1, the removal rates were 575.5% for BOD, 68.2% for COD, 94.5% for TP, and 86.3% for TN.

[0044] Comparative Example 3

[0045] The difference from Example 1 is that the middle filter layer filler 6 is gravel with a particle size of 2mm to 6mm and a thickness of 800mm.

[0046] Using the same test method as in Example 1, the removal rates of BOD5, COD, TP, and TN were 70.1%, 58.3%, 80.7%, and 54.2%, respectively.

[0047] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many modifications under the guidance of the present invention without departing from the spirit of the present invention, and these modifications are all within the protection scope of the present invention.

Claims

1. A plant-based gravel ecological filter dam, characterized in that, The dam body (1) includes a dam body (1), wire mesh (2), aquatic plants (4), a surface covering layer filler (5), a middle filter layer filler (6), a middle and lower transition layer filler (7), and a bottom drainage layer filler (8). The dam body (1) is a trough with an open top. The dam body (1) has four side walls, namely two long side walls and two short side walls. Water-permeable holes (3) are made on the two long side walls, and wire mesh (2) is fixed on the inner wall of the two long side walls. The surface covering layer filler (5), the middle filter layer filler (6), the middle and lower transition layer filler (7), and the bottom drainage layer filler (8) are arranged sequentially from top to bottom in the dam body (1). Aquatic plants (4) are planted on the top surface of the surface covering layer filler (5). The surface cover filler (5) is gravel with a particle size of 10mm~30mm, a thickness of 200mm~300mm, and a porosity of 45%~50% after filling; The middle layer filter media (6) is a mixture of gravel with a particle size of 2mm to 6mm, macroporous cation adsorption resin with a particle size of 1.25mm to 5mm, and camphor wood with a particle size of 2mm to 5mm in a volume ratio of 1:1:1, with a filling thickness of 400mm to 1400mm and a filling porosity of 30% to 35%. The middle and lower transition layer filler (7) is gravel with a particle size of 5mm to 10mm, a filling thickness of 200mm to 300mm, and a filling porosity of 35% to 45%. The bottom drainage layer filler (8) is a mixture of sand and gravel with a particle size of 10mm to 150mm, with a filling thickness of 200mm to 300mm and a filling porosity of 45% to 55%. The untreated river water flows through the permeable holes of the filter dam. The large-pore cationic adsorption resin and camphor wood in the middle layer of filter media can adsorb nitrogen and phosphorus nutrients in the water. Aquatic plants then absorb nutrients from the middle layer of filter media through their roots as nutrients for their own growth. This achieves resource reuse while also effectively adsorbing and degrading pollutants in the water. Camphor wood provides a carbon source for microorganisms in the water, creating a more stable growth and attachment environment. The biofilm formed on the surface of the filter media can further attach to and degrade pollutants in the water. The macroporous cation adsorption resin is pretreated before use. The pretreatment method is as follows: first, wash with water and ethanol in sequence, then rinse with 3% HCl at a rate of 2-3 BV / h, then wash with water until neutral, and finally repeat the above operation with NaOH instead of HCl to complete the pretreatment of the resin. The camphor wood requires pretreatment. The pretreatment method is as follows: water is taken from the polluted river to be treated and used to soak the camphor wood for 120 days, then soaked in a 1% sodium bicarbonate solution for 1-2 hours, cleaned and then soaked in distilled water for later use.

2. The plant-gravel ecological filter dam according to claim 1, characterized in that, The aquatic plants (4) are emergent plants suitable for the local temperature and climate, and are planted in combination according to ecological and landscape diversity.

3. The plant-gravel ecological filter dam according to claim 1, characterized in that, The permeable holes (3) have a diameter of 40~60mm and a spacing of 20~40mm; the wire mesh (2) has a mesh size of 0.5~2mm.

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