A functional filter and plant coupled surface runoff purification system
The surface runoff purification system, which couples functional filter media with plants, solves the problems of simple structure and secondary pollution in bioretention systems, and achieves efficient removal of pollutants from surface runoff, thereby improving water purification capacity and ecosystem diversity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- THE FOURTH ENG CO LTD OF CTCE GRP
- Filing Date
- 2025-05-09
- Publication Date
- 2026-06-26
AI Technical Summary
Existing bioretention systems have a simple structure, limited effectiveness in controlling surface runoff pollution, and may cause secondary pollution problems.
The surface runoff purification system, which couples functional filter media with plants, includes a cover layer, a filler layer, a transition layer, and a drainage layer. It uses functional filter media such as modified zeolite, volcanic rock, sponge iron, and sludge enriched with nitrifying bacteria, combined with a multi-layer filter structure and plant roots, to achieve efficient removal of pollutants.
It significantly improves water purification efficiency, enhances pollutant removal, extends system lifespan, and promotes ecosystem diversity. It can effectively remove suspended solids, heavy metals, nitrogen, phosphorus, and organic pollutants.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of water environment management technology, specifically to a surface runoff purification system that couples functional filter media with plants. Background Technology
[0002] Surface runoff refers to the water that, after rainwater falls to the ground, is intercepted by vegetation, absorbed and infiltrated by the soil, and then flows across the surface of the watershed, eventually flowing into rivers, lakes, and seas. However, with the acceleration of urbanization and the continuous expansion of infrastructure construction such as highways and railways, the proportion of paved urban surfaces is increasing. This not only alters the natural hydrological cycle but also disrupts the original water circulation system, leading to a series of urban surface runoff-related problems. These problems include: during heavy rainfall, rainwater is less able to infiltrate the ground, resulting in faster water accumulation, significantly increased surface runoff volume, higher peak flow, and longer duration. These factors exceed the carrying capacity of urban drainage systems, frequently causing urban flooding and leading to a drop in groundwater levels. Furthermore, due to factors such as air pollution, smog, and dust, rainfall itself contains a certain amount of pollutants. When rainwater reaches the ground, surface runoff further erodes various surfaces. Combined with pollutants from urban industrial emissions, construction waste, asphalt pavements, vehicle exhaust, and household garbage, this leads to a significant increase in the levels of suspended particulate matter, nutrients, organic compounds, heavy metals, and pathogenic microorganisms in the surface runoff. Ultimately, this pollutant-laden surface runoff flows into rivers, lakes, oceans, or reservoirs, posing a serious threat to the environment, ecosystems, and human health.
[0003] To address the severe hazards posed by surface runoff, a series of engineering control measures have been developed both domestically and internationally to combat runoff pollution. These measures can be broadly categorized into three levels: source control, diffusion pathway control, and end-of-pipe treatment. Source control methods include permeable pavement, storm drain interception facilities, vegetated swales, filter trenches, and vegetated buffer zones, aiming to reduce surface runoff occurrence and increase direct rainwater infiltration, thereby mitigating pollution of downstream water bodies. Diffusion pathway control focuses on intercepting and purifying pollutants during runoff through bioretention facilities and artificial soil infiltration, slowing runoff velocity, and reducing its environmental impact. End-of-pipe treatment measures mainly include the construction of storm drains and artificial wetlands for the final treatment and purification of runoff that cannot be effectively controlled upstream. These facilities can also serve as part of the urban landscape, providing recreational and ecological services.
[0004] However, most existing bioretention systems employ sunken green space designs, resulting in a relatively simple structure and limited effectiveness in controlling surface runoff pollution. Furthermore, these systems typically use native soil as the filter layer material, which may lead to low efficiency in removing pollutants carried in surface runoff and could even release nutrients such as nitrogen and phosphorus, as well as heavy metals, causing secondary pollution problems.
[0005] In view of the above-mentioned defects, the inventors of this invention have finally obtained this invention after a long period of research and practice. Summary of the Invention
[0006] The purpose of this invention is to address the problems of current bioretention systems having a relatively simple structure, limited control effect on surface runoff pollution, low efficiency in removing pollutants carried in surface runoff, and even the potential release of nutrients such as nitrogen and phosphorus and heavy metals, causing secondary pollution. This invention provides a surface runoff purification system that couples functional filter media with plants.
[0007] To achieve the above objectives, the present invention discloses a surface runoff purification system coupled with functional filter media and plants, comprising a cover layer, a filler layer, a transition layer and a drainage layer. The cover layer is planted with plants, the filler layer comprises functional filter media and fine sand, the weight ratio of the functional filter media and fine sand is 1:2, the transition layer is coarse sand, and the drainage layer is gravel.
[0008] The plant is any one or more combinations of reeds, cattails, and foxtail grass.
[0009] The covering layer comprises organic matter and medium sand, wherein the weight ratio of organic matter to medium sand is 4:1, the fineness modulus of the medium sand is 2.2 to 2.6, and the organic matter is any one or a combination of two of nutrient soil and sawdust.
[0010] The functional filter media comprises, by weight, 9-11 parts of sludge enriched with nitrifying bacteria, 6-8 parts of volcanic rock, 4-6 parts of sponge iron, and 2-4 parts of modified zeolite, wherein the modified zeolite is modified by acidification, reheating, and re-bromoacetic acid modification.
[0011] The preparation method of the functional filter material includes the following steps:
[0012] S1. The volcanic rock is crushed into particles of 2-6 mm, soaked in an acidic solution, washed with deionized water until neutral, and then treated with an alkaline solution to obtain pretreated volcanic rock.
[0013] S2, the sponge iron is washed with a second acidic solution and dried. The washed and dried sponge iron particles are added to an amino acid solution and reacted for 1 to 4 hours to obtain pretreated sponge iron.
[0014] S3 involves mixing and ball milling modified zeolite, pretreated volcanic rock, and pretreated sponge iron until the particle size is 0.4–0.6 mm. Then, sludge enriched with nitrifying bacteria is added, mixed, granulated, and dried for 2–4 hours to obtain functional filter media.
[0015] In step S1, the first acidic solution is 0.1-0.3 mol / L hydrochloric acid, and the alkaline solution is 0.2-0.4 mol / L sodium hydroxide. In step S2, the second acidic solution is 0.2-0.4 mol / L hydrochloric acid, and the amino acid solution is any one of glycine, glutamic acid, and arginine.
[0016] The preparation method of the modified zeolite includes the following steps:
[0017] A1. Natural zeolite is crushed, sieved through a 2-4 mm sieve, washed, and dried to obtain pretreated zeolite.
[0018] A2. Soak the pretreated zeolite in an acidic solution for 18–24 hours, then remove, wash, and dry.
[0019] A3, heat the zeolite dried in step A2 at 400-600℃ for 2-4 hours;
[0020] A4. The zeolite heated in step A3 is immersed in bromoacetic acid solution for 10-12 hours, then removed, washed, and dried to obtain modified zeolite.
[0021] In step A2, the acidic solution is 0.1–0.5 mol / L hydrochloric acid or sulfuric acid; in step A4, the molar concentration of the bromoacetic acid solution is 1–3 mol / L.
[0022] The total thickness of the covering layer, filler layer, transition layer and drainage layer is 0.5 to 1.5 m; the thickness of the covering layer is not less than 50 mm, the thickness of the filler layer is not less than 200 mm, the thickness of the transition layer is not less than 100 mm, and the thickness of the drainage layer is not less than 150 mm.
[0023] The fineness modulus of the coarse sand used in the transition layer is 3.2 to 3.6; the particle size of the crushed stone used in the drainage layer is 20 to 50 mm.
[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0025] 1. This invention utilizes the synergistic effect of functional filter media, plants, and a multi-layered filter structure to efficiently remove suspended solids, heavy metals, nitrogen, phosphorus, and organic pollutants from runoff. The functional filter media in the packing layer exhibits excellent adsorption and chemical reaction capabilities for various pollutants, significantly improving water purification efficiency. The system's structural design filters and slowly releases runoff layer by layer from top to bottom, increasing water permeability and retention time, further enhancing pollutant removal. The root system of the covering plants also promotes this process, significantly improving the overall water purification capacity of the system. Furthermore, the coarse sand in the transition layer and the gravel in the drainage layer effectively prevent fine sand and functional filter media from moving to deeper layers, reducing the risk of system blockage, ensuring long-term unobstructed operation, and extending the system's service life. Moreover, the plants in the covering layer not only play a crucial role in water purification but also beautify the environment and enhance ecosystem diversity. Their root systems provide an ideal habitat for microorganisms, promoting biodegradation and contributing to the continuous and effective removal of organic pollutants from runoff.
[0026] 2. The functional filter media of this invention, through acid-alkali treatment, amino acid modification, and ball milling, significantly increases the specific surface area of volcanic rock, sponge iron, and modified zeolite, greatly enhancing their adsorption capacity for suspended solids, heavy metal ions, and organic pollutants in water. Furthermore, incorporating granulated sludge rich in nitrifying bacteria into the filter media not only endows it with strong biodegradation capabilities but also efficiently removes nutrient pollutants such as ammonia nitrogen from the water, effectively mitigating eutrophication caused by runoff pollution. To ensure the structural stability and continuous performance of the filter media, a mixing granulation and drying technology is employed. This maintains high porosity while enhancing the mechanical strength of the filter media, preventing pulverization and clogging after prolonged use, thereby extending its service life and improving the system's purification effect. It can broadly remove various pollutants from runoff, such as heavy metals, nitrogen oxides, and organic matter.
[0027] 3. Bromoacetic acid modification imbues the zeolite surface with carboxyl and bromide groups, increasing its affinity for cationic pollutants such as heavy metal ions and ammonia nitrogen, thereby enhancing its selective adsorption capacity. Modified zeolite can not only efficiently adsorb heavy metal ions but also remove some organic matter and ionic pollutants such as ammonia nitrogen from water, making it suitable for purifying complex polluted water bodies. Heat treatment improves the zeolite's heat resistance and structural stability, extending its stable adsorption capacity during use and enabling long-term operation under a wide range of environmental conditions. Detailed Implementation
[0028] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the embodiments.
[0029] Example 1
[0030] 1. The preparation steps of modified zeolite include:
[0031] A1. 4 kg of natural zeolite is crushed, sieved through a 2 mm sieve, washed, and dried to obtain pretreated zeolite.
[0032] A2, soak the pretreated zeolite in 0.1 mol / L hydrochloric acid for 24 hours, then remove, wash, and dry;
[0033] A3, Heat the zeolite from step A2 at 400℃ for 4 hours;
[0034] A4. The zeolite from step A3 was soaked in a 1 mol / L bromoacetic acid solution for 12 h, then removed, washed, and dried to obtain the modified zeolite.
[0035] 2. The preparation steps of functional filter media include:
[0036] S1. 6 kg of volcanic rock was crushed into 2 mm particles, soaked in 0.1 mol / L hydrochloric acid, washed with deionized water until neutral, and then treated with 0.2 mol / L sodium hydroxide to obtain pretreated volcanic rock.
[0037] S2, 4 kg of sponge iron was washed with 0.2 mol / L hydrochloric acid, dried, and the washed and dried sponge iron particles were added to glycine solution and reacted for 1 h to obtain pretreated sponge iron;
[0038] S3. Mix and ball-mill 2kg of modified zeolite, pretreated volcanic rock and pretreated sponge iron until the particle size is 0.4mm. Then add 9kg of sludge enriched with nitrifying bacteria, mix and granulate, and dry for 2h to obtain functional filter media.
[0039] A surface runoff purification system coupled with functional filter media and plants is disclosed. The system consists of a cover layer, a filler layer, a transition layer, and a drainage layer from top to bottom. The cover layer is planted with reeds and is composed of a mixture of organic matter and medium sand in a weight ratio of 4:1, wherein the fineness modulus of the medium sand is 2.2 and the organic matter is nutrient soil. The filler layer is composed of a mixture of functional filter media and fine sand in a weight ratio of 1:2. The transition layer is composed of coarse sand with a fineness modulus of 3.2, and the drainage layer is composed of crushed stone with a particle size of 20.
[0040] Example 2
[0041] 1. The preparation steps of modified zeolite include:
[0042] A1. Crush 6 kg of natural zeolite, sieve it through a 3 mm sieve, wash it, and dry it to obtain pretreated zeolite.
[0043] A2, the pretreated zeolite was soaked in 0.4 mol / L hydrochloric acid for 21 h, then removed, washed, and dried;
[0044] A3, Heat the zeolite from step A2 at 500℃ for 3 hours;
[0045] A4. The zeolite from step A3 was soaked in a 2 mol / L bromoacetic acid solution for 11 h, then removed, washed, and dried to obtain the modified zeolite.
[0046] 2. The preparation steps of functional filter media include:
[0047] S1. 7 kg of volcanic rock was crushed into 4 mm particles, soaked in 0.2 mol / L hydrochloric acid, washed with deionized water until neutral, and then treated with 0.3 mol / L sodium hydroxide to obtain pretreated volcanic rock.
[0048] S2, 5 kg of sponge iron was washed with 0.3 mol / L hydrochloric acid, dried, and the washed and dried sponge iron particles were added to glycine solution and reacted for 2.5 h to obtain pretreated sponge iron;
[0049] S3, 3kg of modified zeolite, pretreated volcanic rock and pretreated sponge iron are mixed and ball-milled until the particle size is 0.5mm. Then, 10kg of sludge enriched with nitrifying bacteria is added, mixed and granulated, and dried for 3h to obtain functional filter media.
[0050] A surface runoff purification system coupled with functional filter media and plants is disclosed. The system consists of a cover layer, a filler layer, a transition layer, and a drainage layer from top to bottom. The cover layer is planted with reeds and is composed of a mixture of organic matter and medium sand in a weight ratio of 4:1, wherein the fineness modulus of the medium sand is 2.4 and the organic matter is nutrient soil. The filler layer is composed of a mixture of functional filter media and fine sand in a weight ratio of 1:2. The transition layer is composed of coarse sand with a fineness modulus of 3.4. The drainage layer is composed of gravel with a particle size of 35mm.
[0051] Example 3
[0052] The preparation steps of modified zeolite include,
[0053] A1. 8 kg of natural zeolite is crushed, sieved through a 4 mm sieve, washed, and dried to obtain pretreated zeolite.
[0054] A2, soak the pretreated zeolite in 0.5 mol / L hydrochloric acid for 18 hours, take it out, wash it, and dry it;
[0055] A3, Heat the zeolite from step A2 at 600℃ for 2 hours;
[0056] A4. The zeolite from step A3 was soaked in a 3 mol / L bromoacetic acid solution for 10 h, then removed, washed, and dried to obtain the modified zeolite.
[0057] The preparation steps of functional filter media include:
[0058] S1. 8 kg of volcanic rock was crushed into 6 mm particles, soaked in 0.3 mol / L hydrochloric acid, washed with deionized water until neutral, and then treated with 0.4 mol / L sodium hydroxide to obtain pretreated volcanic rock.
[0059] S2, 6 kg of sponge iron was washed with 0.4 mol / L hydrochloric acid, dried, and the washed and dried sponge iron particles were added to glycine solution and reacted for 4 h to obtain pretreated sponge iron.
[0060] S3. Mix 4 kg of modified zeolite, pretreated volcanic rock, and pretreated sponge iron and ball mill until the particle size is 0.6 mm. Then add 11 kg of sludge enriched with nitrifying bacteria, mix and granulate, and dry for 4 hours to obtain functional filter media.
[0061] A surface runoff purification system coupled with functional filter media and plants is disclosed. The system consists of a cover layer, a filler layer, a transition layer, and a drainage layer from top to bottom. The cover layer is planted with reeds and is composed of a mixture of organic matter and medium sand in a weight ratio of 4:1, wherein the fineness modulus of the medium sand is 2.6 and the organic matter is nutrient soil. The filler layer is composed of a mixture of functional filter media and fine sand in a weight ratio of 1:2. The transition layer is composed of coarse sand with a fineness modulus of 3.6, and the drainage layer is composed of gravel with a particle size of 50 mm.
[0062] Example 4
[0063] The difference between this embodiment and Embodiment 2 is that the plant used in this embodiment is cattail. Other preparation processes are the same as in Embodiment 2.
[0064] Example 5
[0065] The difference between this embodiment and Embodiment 2 is that the plant used in this embodiment is Myriophyllum spicatum. Other preparation processes are the same as in Embodiment 2.
[0066] Comparative Example 1
[0067] The difference between this embodiment and Embodiment 2 is that the preparation steps of this functional filter material are as follows: 3 kg of modified zeolite, 7 kg of volcanic rock, and 5 kg of sponge iron are mixed and ball-milled until the particle size is 0.4-0.6 mm. Then, 9-11 kg of sludge enriched with nitrifying bacteria is added, mixed, granulated, and dried for 2-4 hours to obtain the functional filter material. Other preparation processes are the same as in Embodiment 2.
[0068] Comparative Example 2
[0069] The difference between this embodiment and Embodiment 2 is that no zeolite modification is performed; ordinary zeolite is used directly. Other preparation processes are the same as in Embodiment 2.
[0070] Comparative Example 3
[0071] The difference between this embodiment and Embodiment 2 is that sludge enriched with nitrifying bacteria is used to replace the functional filter media. Other preparation processes are the same as in Embodiment 2.
[0072] Comparative Example 4
[0073] The difference between this embodiment and Embodiment 2 is that volcanic rock is used to replace the functional filter media. All other preparation processes are the same as in Embodiment 2.
[0074] Comparative Example 5
[0075] The difference between this embodiment and Embodiment 2 is that sponge iron is used instead of the functional filter material. All other preparation processes are the same as in Embodiment 2.
[0076] Comparative Example 6
[0077] The difference between this embodiment and Embodiment 2 is that modified zeolite is used to replace the functional filter media. All other preparation processes are the same as in Embodiment 2.
[0078] Comparative Example 7
[0079] The difference between this embodiment and Embodiment 2 is that no functional filter material is used. All other preparation processes are the same as in Embodiment 2.
[0080] Comparative Example 8
[0081] The difference between this embodiment and Example 2 is that step A4, the bromoacetic acid reaction, is omitted in the modified zeolite process; the zeolite is directly dried. Other preparation processes are the same as in Example 2.
[0082] A simulation experimental apparatus (numbered 1-12) was built and brought to normal operation according to the systems in Examples 1-5 and Comparative Examples 1-8, with dimensions of 0.2*1*0.5m (length*width*height); simulated surface (rainwater) runoff was used for water intake. The system's normal operating water intake was 1.5m³. 3 Each influent run lasted 4 hours, with an influent volume equivalent to the amount of water flowing into the surface runoff purification system when the total rainfall was 42 mm. The process was repeated 3 times (with an interval of 10 hours between each influent run), and the effluent quality was tested regularly, with the average value taken. The results are shown in Table 1-2.
[0083] Table 1. Test results of TSS, TN and TP in the surface runoff purification system
[0084]
[0085]
[0086] Table 2. Heavy metal detection results of surface runoff purification system
[0087]
[0088] As shown in Tables 1 and 2, this surface runoff purification system, which couples functional filter media with plants, not only has outstanding purification capabilities, but also has high efficiency and significant effect in removing pollutants carried in the influent, successfully realizing the recycling of rainwater and runoff resources.
[0089] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.
Claims
1. A surface runoff purification system coupling functional filter media and plants, characterized in that, The system comprises a cover layer, a filler layer, a transition layer, and a drainage layer. The cover layer is planted with vegetation. The filler layer consists of functional filter media and fine sand in a weight ratio of 1:
2. The transition layer is composed of coarse sand, and the drainage layer is composed of gravel. The functional filter media, by weight, comprises 9-11 parts of sludge enriched with nitrifying bacteria, 6-8 parts of volcanic rock, 4-6 parts of sponge iron, and 2-4 parts of modified zeolite. The modified zeolite is modified by acidification, reheating, and re-bromoacetic acid modification.
2. The surface runoff purification system coupled with functional filter media and plants as described in claim 1, characterized in that, The plant is any one or more combinations of reeds, cattails, and foxtail grass.
3. The surface runoff purification system coupled with functional filter media and plants as described in claim 1, characterized in that, The covering layer comprises organic matter and medium sand, wherein the weight ratio of organic matter to medium sand is 4:1, the fineness modulus of the medium sand is 2.2 to 2.6, and the organic matter is any one or a combination of two of nutrient soil and sawdust.
4. The surface runoff purification system coupled with functional filter media and plants as described in claim 1, characterized in that, The preparation method of the functional filter material includes the following steps: S1. The volcanic rock is crushed into 2-6mm particles, soaked in a first acidic solution, washed with deionized water until neutral, and then treated with an alkaline solution to obtain pretreated volcanic rock. S2, the sponge iron is washed with a second acidic solution and dried. The washed and dried sponge iron particles are added to an amino acid solution and reacted for 1-4 hours to obtain pretreated sponge iron. S3 involves mixing and ball milling modified zeolite, pretreated volcanic rock, and pretreated sponge iron until the particle size is 0.4~0.6mm. Then, sludge enriched with nitrifying bacteria is added, mixed, granulated, and dried for 2~4 hours to obtain functional filter media.
5. A surface runoff purification system coupled with functional filter media and plants as described in claim 4, characterized in that, In step S1, the first acidic solution is 0.1~0.3 mol / L hydrochloric acid, and the alkaline solution is 0.2~0.4 mol / L sodium hydroxide. In step S2, the second acidic solution is 0.2~0.4 mol / L hydrochloric acid, and the amino acid solution is any one of glycine, glutamic acid, and arginine.
6. A surface runoff purification system coupled with functional filter media and plants as described in claim 1, characterized in that, The preparation method of the modified zeolite includes the following steps: A1. Crush natural zeolite, sieve it to 2-4 mm, wash it, and dry it to obtain pretreated zeolite. A2. Soak the pretreated zeolite in an acidic solution for 18-24 hours, then remove, wash, and dry. A3, heat the zeolite dried in step A2 at 400~600℃ for 2~4 hours; A4. The zeolite heated in step A3 is soaked in bromoacetic acid solution for 10-12 hours, then removed, washed, and dried to obtain modified zeolite.
7. A surface runoff purification system coupled with functional filter media and plants as described in claim 6, characterized in that, In step A2, the acidic solution is 0.1~0.5 mol / L hydrochloric acid or sulfuric acid; in step A4, the molar concentration of the bromoacetic acid solution is 1~3 mol / L.
8. A surface runoff purification system coupled with functional filter media and plants as described in claim 1, characterized in that, The total thickness of the covering layer, filler layer, transition layer and drainage layer is 0.5~1.5m; the thickness of the covering layer is not less than 50mm, the thickness of the filler layer is not less than 200mm, the thickness of the transition layer is not less than 100mm, and the thickness of the drainage layer is not less than 150mm.
9. A surface runoff purification system coupled with functional filter media and plants as described in claim 1, characterized in that, The fineness modulus of the coarse sand used in the transition layer is 3.2 to 3.6; the particle size of the crushed stone used in the drainage layer is 20 to 50 mm.