CN110241906A - Rainwater purification and reuse bioretention system - Google Patents

Abstract

The invention discloses a biological retention system for rainwater purification and reuse. The system includes a rain garden and a landscape fountain. The rain garden includes a vegetation layer, a covering layer, a filler layer, a geotextile layer, a supporting layer and a drainage layer from top to bottom. Plants are planted on the filler layer, and the filler layer includes soil, River sand, peat soil, zeolite, vermiculite and remaining sludge from waterworks; fountain pool of landscape fountain, fountain pool is provided with disinfection layer, water storage layer and fountain layer in sequence from bottom to top, and sedimentation tank is provided at the bottom of fountain pool; disinfection The layer is provided with ultraviolet light tubes, and the disinfection layer is connected with the drainage layer; the submersible pump in the water storage layer supplies the water in the water storage layer to the fountain water pipe and sprays it out on the fountain layer. The system can provide a good environment for plant growth and effectively remove pollutants in stormwater runoff, and purify rainwater as water for landscape fountains, which can supplement urban landscape water and reduce municipal drainage pressure.

Description

Rainwater purification and reuse bioretention system

technical field

The invention belongs to the field of sponge city construction, and in particular relates to a rainwater purification and reuse biological retention system.

Background technique

The rapid development of urbanization has directly changed the nature and morphological characteristics of the underlying surface, aggravating the pollution of rainfall runoff, and carrying a large amount of pollutants (suspended solids, nitrogen, phosphorus, etc.) in the runoff, thus triggering a series of urban water environment problems. Among them, the eutrophication and black and odor problems of urban rivers are particularly prominent. Bioretention facilities are widely used low-impact development facilities, which can effectively reduce and control the migration of runoff pollutants from the source. Bioretention facilities mainly use the joint action of plants, fillers and microorganisms to remove pollutants through physical, chemical and biological reactions. Remove runoff pollutants, so as to achieve the function of purifying water quality. Among them, the filler is a key factor in purifying water quality. It not only provides a good environment for plant growth, but also provides an adaptive environment for the growth and reproduction of microorganisms. The components in the filler can also directly remove pollutants in runoff through physical and chemical effects. At present, most bioretention facilities are divided into cover layer, planting soil layer, geotextile layer, filler layer, geotextile layer, supporting layer and drainage layer, with many layers and high operation and maintenance costs; in addition, the low-impact development facilities The outlet water is subject to the restriction that the maximum dynamic water level from the bottom of the facility must be greater than 1m. Generally, direct infiltration is not allowed, and it needs to be collected uniformly and discharged into the municipal drainage pipe network. Therefore, bioretention facilities still need to be further improved.

Contents of the invention

The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

The present invention is completed based on the following concepts: on the one hand, the composition and ratio of the filler are adjusted, and the planting soil layer and the filler layer are combined into one to reduce the operation and operation and maintenance costs of the bioretention facility; on the other hand, the bioretention facility is used to Remove a variety of pollutants in the runoff, and reuse the effluent from bioretention facilities as landscape water after ultraviolet disinfection treatment. Landscape water is an important part of the modern urban water environment. The state stipulates that tap water or groundwater cannot be used to replenish landscape water. Using the effluent of bioretention facilities as supplementary water for landscape water bodies can not only improve the comprehensive benefits of the facilities, but also alleviate the difficulty of supplementing water sources for urban landscape water bodies in my country and reduce the pressure on municipal drainage.

Therefore, an object of the present invention is to propose a bioretention system for rainwater purification and reuse. The system not only requires less operation and low maintenance cost, but also can provide a good environment for plant growth and effectively remove pollutants in rainwater runoff. At the same time, by purifying rainwater and using it as landscape fountain water, it is not only ornamental, but also relieves urban pollution in our country. Difficulties in supplementing landscape water sources and municipal drainage pressure have good social and environmental benefits.

According to one aspect of the present invention, the present invention proposes a rainwater purification and reuse bioretention system. According to an embodiment of the present invention, the system includes:

The rain garden comprises a vegetation layer, a cover layer, a filler layer, a geotextile layer, a supporting layer and a drainage layer from top to bottom, wherein plants are planted in the filler layer and above the cover layer Form the vegetation layer, the filler layer includes natural bag, zeolite, vermiculite and excess sludge from waterworks, the natural bag includes soil, river sand and peat soil, and the covering layer includes wood blocks and bark;

A landscape fountain, the landscape fountain includes a fountain pool, and the fountain pool is provided with a disinfection layer, a water storage layer and a fountain layer sequentially from bottom to top, wherein a settlement tank is provided at the bottom of the fountain pool; the disinfection layer is provided with The ultraviolet lamp tube, and the disinfection layer is connected with the drainage layer; the water storage layer is provided with a submersible pump, and the water in the water storage layer is supplied by the submersible pump to the fountain water pipe and the water in the fountain layer The sprayed water returns to the water storage layer; the upper part of the fountain layer is provided with a water outlet, and the water outlet is connected to the municipal drainage pipe.

According to the rainwater purification and reuse bioretention system of the above-mentioned embodiments of the present invention, on the one hand, the inventors found that the excess sludge from waterworks contains more elements such as iron and aluminum, and has a relatively strong adsorption force for phosphorus. The remaining sludge is used in the filler layer of the rain garden, which not only does not affect the growth of plants, but also makes the filler layer have a better and lasting dephosphorization effect. In the present invention, there is no need to set the planting soil layer separately, and the soil, river sand , peat soil, zeolite, vermiculite and residual sludge from waterworks are mixed as a filler layer, which can not only satisfy the growth of plants, but also effectively remove pollutants such as suspended solids, ammonia nitrogen and phosphorus in rainfall runoff. Among them, the rainwater runoff passes through the rain garden After purification, the removal rate of suspended matter can reach more than 85%, the removal rate of phosphorus can reach more than 93%, the removal rate of ammonia nitrogen can reach 65-85%, and the COD _Cr can be reduced by 65-80%. On the other hand, in the present invention, by using ultraviolet light tubes to disinfect the effluent of the rain garden, the effluent can meet the water quality requirements of the landscape water, and then using it in the landscape fountain can not only improve the efficiency of the entire treatment system, but also relieve the pollution of urban areas in our country. Difficulties in replenishing landscape water sources and municipal drainage pressure; while the water in the water storage layer of the fountain pool forms a fountain through the action of the submersible pump for viewing, and then returns to the water storage layer for recycling, which can make the water in the fountain pool be in a dynamic cycle , to ensure the content of dissolved oxygen in the water body, and reduce the risk of secondary pollution caused by water quality deterioration. To sum up, the system not only requires less operation and low maintenance cost, but also can provide a good environment for plant growth and effectively remove pollutants in rainwater runoff. At the same time, by purifying rainwater as water for landscape fountains, it is not only ornamental, It can also alleviate the difficulty of replenishing water sources for urban landscape water bodies in my country and the pressure of municipal drainage, and has good social and environmental benefits.

In addition, the rainwater purification and reuse bioretention system according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

In some embodiments of the present invention, the excess sludge from the waterworks is dewatered dry sludge, and the mass ratio of the natural bag, the zeolite, the vermiculite and the dehydrated dry sludge is (50-70) : (5～20): (5～20): (10～30), the mass ratio of described soil, described river sand and described peat soil is (40～50): (30～40): (10 ~20). In this way, it can not only provide sufficient nutrients and a good growth environment for plant growth, but also achieve better rainwater purification effect.

In some embodiments of the present invention, the particle size of the soil is not greater than 0.5mm, the particle size of the river sand is 0.06-0.5mm, the particle size of the peat soil is not greater than 5mm, and the particle size of the vermiculite is The particle size of the zeolite is 5-10 mm, and the particle size of the dehydrated dry sludge is not greater than 0.5 mm. This not only makes the mixing of the components in the filler layer more uniform, but also facilitates the release of nutrients, and makes the components in the filler layer fully contact with rainwater, which is more conducive to plant growth and can achieve better Rainwater purification effect.

In some embodiments of the present invention, the content of organic matter in the filler layer is 3-5wt%, the content of clay is not more than 5wt%, the content of nitrogen is not more than 1000mg/Kg, and the content of phosphorus is not more than 80mg/Kg. In this way, it can not only provide sufficient nutrients for plant growth, but also ensure that the filler layer has a suitable water-permeability and achieve a better nitrogen and phosphorus removal effect.

In some embodiments of the present invention, the covering layer has a thickness of 50-100 mm, the filler layer has a thickness of 500-800 mm, and the supporting layer has a thickness of 200-300 mm. As a result, the purification effect of the rain garden can be further improved.

In some embodiments of the present invention, the supporting layer is a gravel layer, and the particle size of the gravel is 10-20 mm. In this way, not only a better supporting effect can be achieved, but also the drainage effect is not affected.

In some embodiments of the present invention, the geotextile layer is a non-woven polypropylene filament geotextile layer. In this way, a better effect of water permeability and sand impermeability can be achieved.

In some embodiments of the present invention, the plant is at least one selected from the group consisting of honeysuckle, dwarf crape myrtle, hexapia, amorpha, pennisetum, blue fescue, Suaeda salsa, cone phlox and Malian A sort of.

In some embodiments of the present invention, the ultraviolet lamp tubes are arranged side by side along the length direction of the disinfection layer, and the distance between two adjacent ultraviolet lamp tubes is 20-30 cm. This can ensure that the water in the disinfection layer can be fully irradiated by the ultraviolet lamp, thereby further improving the disinfection effect and avoiding secondary pollution caused by deterioration of water quality.

In some embodiments of the present invention, the volume of the fountain pool is: V=Ψh _m aK, wherein, in the formula, V- is the volume of the fountain pool, m ³ ; Ψ- is the rainfall runoff coefficient; h _m - is The design rainfall intensity corresponding to the total annual runoff control rate of 80% to 85%, mm; a- is the area of the rain garden, hm ² ; K- is the ratio of the service area of the rain garden to its area, The value range of K is 10-20. As a result, not only can the water from the rain garden be fully used for landscape fountains as much as possible, reducing the pressure on municipal drainage, but also further reducing the maintenance and operation costs of fountain pools.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and comprehensible from the description of the embodiments in conjunction with the following drawings, wherein:

Fig. 1 is a schematic structural diagram of a rainwater purification and reuse bioretention system according to an embodiment of the present invention.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

According to one aspect of the present invention, the present invention proposes a rainwater purification and reuse bioretention system. According to an embodiment of the present invention, as shown in FIG. 1 , the system includes a rain garden 100 and a landscape fountain 200 . The system not only requires less operation and low maintenance cost, but also can provide a good environment for plant growth and effectively remove pollutants in rainwater runoff. At the same time, by purifying rainwater and using it as landscape fountain water, it is not only ornamental, but also relieves urban pollution in our country. Difficulties in supplementing landscape water sources and municipal drainage pressure have good social and environmental benefits.

The rainwater purification and reuse bioretention system of the above embodiment of the present invention will be described in detail below with reference to FIG. 1 .

Rain Garden 100

According to an embodiment of the present invention, the rain garden 100 includes a vegetation layer 110, a covering layer 120, a filler layer 130, a geotextile layer 140, a supporting layer 150 and a drainage layer 160 from top to bottom, wherein plants are planted on the filler layer 130 The vegetation layer 110 is formed in the center and above the cover layer 120, the filler layer 130 includes natural bag, zeolite, vermiculite and excess sludge from waterworks, the natural bag includes soil, river sand and peat soil, and the cover layer 120 includes wood blocks and bark. The inventors found that the excess sludge from the waterworks contains more elements such as iron and aluminum, and has a relatively strong adsorption force on phosphorus. Using the excess sludge from the waterworks in the filling layer of the rain garden will not only not affect the growth of plants , can also make the filler layer have a better and lasting dephosphorization effect. In the present invention, the rain garden does not need to be provided with a separate planting soil layer. By mixing soil, river sand, peat soil, zeolite, vermiculite and waterworks residual sludge The filler layer can not only satisfy the growth of plants, but also effectively remove pollutants such as suspended solids, ammonia nitrogen and phosphorus in the rainfall runoff. Among them, after the rainwater runoff is purified by the rain garden, the removal rate of suspended solids can reach more than 85%. The removal rate of ammonia nitrogen can reach more than 93%, the removal rate of ammonia nitrogen can reach 65-90%, and the COD _Cr can be reduced by 65-85%.

According to a specific embodiment of the present invention, the types of plants in the present invention are not particularly limited, and those skilled in the art can select according to actual needs. For example, plants with the function of removing pollutants can be selected from the location of the system, preferably plant varieties that can effectively remove nutrients such as nitrogen and phosphorus. At least one of tailgrass, blue fescue, Suaeda salsa, coneflower phlox and Malian, this type of plant has at least the following advantages: strong growth ability, can be planted and grown in large quantities; has good stress resistance, both resistant to Drought and flood tolerance; proper growth rate and growth cycle; dense and well-developed plant roots can not only increase soil porosity and microbial growth space, but also promote denitrification; in harmony with the ecological environment, it has ornamental value and comprehensive utilization value It has good pollution interception and pollution resistance, and can quickly absorb pollutants in water bodies, especially nitrogen. It also has certain pollution resistance. With the continuous entry of rainfall runoff, it has continuous pollution resistance. Preferably, the above-mentioned four kinds of shrubs honeysuckle, dwarf crape myrtle, hexapia, amorpha and five kinds of herbs Pennisetum, blue fescue, Suaeda salsa, cone phlox and Malus can be planted together.

According to another specific embodiment of the present invention, the main function of the covering layer 120 is to retain water, absorb water and protect plants, and its main components are wood blocks and bark, for example, wood blocks with a mass ratio of 1: (1.0-2.0) can be selected. It is evenly mixed with bark and covered on the filler layer, which not only makes the cover layer have certain water retention, water absorption and permeability, but also avoids soil erosion of the filler layer and provides nutrients for plant growth. Wherein, the thickness of the covering layer 120 can be 50-100mm, for example, it can be 50mm, 60mm, 70mm, 80mm, 90mm or 100mm, etc., so that the covering layer can not only have better water retention and water absorption effects, but also avoid the filler layer. Soil erosion and provide a better growth environment for plants. According to a specific example of the invention, the thickness of the covering layer 120 can be 100mm, and can be made up of wood blocks and bark according to the mass ratio of 1:1 or 1:2, thus the comprehensive effect of the covering layer can be further improved, and it can be used for plants. Provides a more favorable environment for growth.

According to another specific embodiment of the present invention, there is no need to set up a planting soil layer in the present invention, and the plants are planted in the filler layer 130, and the requirements for the growth of plants and the removal of pollutants in rainfall runoff are met at the same time by relying on the filler layer, wherein the rainfall runoff The removal of neutral nitrogen mainly includes biological action, mineralization, precipitation, filtration and the adsorption of fillers, the removal of phosphorus mainly depends on the adsorption of fillers, and the removal of suspended solids mainly depends on filtration and precipitation. In the present invention, various fillers Mix well and work together to remove pollutants from rainfall runoff. Specifically, soil, river sand and peat soil can be mixed and formulated into a natural bag to meet the growth of plants, and then on the basis of the natural bag, zeolite and vermiculite, which have the effect of removing ammonia nitrogen, and zeolite, which has the effect of removing phosphorus The remaining sludge in the waterworks, so that the filler layer has a better pollutant removal effect.

According to another specific embodiment of the present invention, the mass ratio of soil, river sand and peat soil in the natural bag can be (40～50):(30～40):(10～20), for example, it can be 46:36: 18. The inventor found that adding an appropriate amount of river sand in the filler layer can help improve the permeability of the filler, but if the amount of river sand is too much, it is not conducive to the growth of plants; and the main component of peat soil is pure natural Organic substances, rich in nitrogen, phosphorus, potassium, calcium, manganese and other elements, are sterile, non-toxic, pollution-free, pollution-free, and residue-free green substances that can improve soil, restore and improve soil Water holding, ventilation and fertilizer retention capacity, and increase the nutrient content of the soil. Adding an appropriate amount of peat soil to the filler layer can not only provide nutrients for plant growth, but also ensure that the plant growth can be satisfied even if the nutrient content in the soil is low. Can also improve the removal ability of pollutant; Among the present invention, by controlling soil, river sand and peat soil to be above-mentioned mass ratio, not only can improve soil, provide better soil environment for plant growth, also help to improve filling layer to water Decontamination effect and penetration effect. Further, the soil selected in the present invention can be the planting soil where the system is located. For example, the planting soil with low nutrient content can be selected, and the soil can be sieved to remove particles with larger particle sizes, so that the soil particle size does not vary. greater than 0.5mm, in addition, the particle size of the river sand used in the present invention can be 0.06 ~ 0.5mm, the particle size of peat soil can be no more than 5mm, thus, can ensure that soil, river sand and peat soil can be evenly mixed with other fillers mix.

According to another specific embodiment of the present invention, the mass ratio of natural bag, zeolite, vermiculite and dewatered dry sludge can be (50～70):(5～20):(5～20):(10～30), The inventors found that the excess sludge from waterworks contains more elements such as iron and aluminum, and has a relatively strong adsorption force for phosphorus. Using the excess sludge from waterworks in the packing layer of the rain garden can make the packing layer have a higher Good and long-lasting dephosphorization effect; and, as a natural non-toxic mineral, vermiculite has good cation exchange and adsorption properties, which can not only improve the structure of the soil, store water and moisture, improve the air permeability and water content of the soil It can also remove ammonia nitrogen, phosphate, rare earth ions and organic pollutants in water; zeolite has the function of water and fertilizer retention, and its surface is positively charged, rough and porous, and has a strong ability to adsorb ammonia nitrogen. The removal rate of ammonia nitrogen can reach more than 95%. In the present invention, the filler layer is formed by mixing the natural bag, zeolite, vermiculite and excess sludge from the waterworks and controlling the above ratio, which can not only provide sufficient nutrients and a good growth environment for plant growth, but also achieve better plant growth. Rainwater purification effect, to ensure that after the rainwater runoff is purified by the rain garden, the removal rate of suspended solids is not lower than 85%, the removal rate of phosphorus is not lower than 93%, the removal rate of ammonia nitrogen is not lower than 68%, and the COD _Cr can be reduced by 65% above.

According to yet another specific embodiment of the present invention, the excess sludge from the waterworks used in the present invention is dewatered dry sludge, which can be ground into a powder with a particle size not greater than 0.5 mm, and the particle size of the vermiculite is controlled to be 0.01 mm. ~0.06mm, the particle size of zeolite is 5~10mm, which can not only ensure a more uniform mixing of natural bag, zeolite, vermiculite and residual sludge from waterworks, but also facilitate the release of nutrients, and make each packing layer The components are in full contact with rainwater, which is more conducive to plant growth and can achieve better rainwater purification effect. In addition, the thickness of the filler layer 130 can be 500-800mm, such as 500mm, 550mm, 600mm, 650mm, 700mm, 750mm or 800mm, etc., which can not only provide a more favorable environment for plant growth, but also further ensure the thickness of the filler layer. The physical, chemical and biological effects on pollutants, including mineralization, precipitation, filtration and adsorption, etc., so as to achieve better rainwater purification effect.

According to another specific embodiment of the present invention, the content of organic matter in the filler layer may be 3-5wt%, the content of clay is preferably no more than 5wt%, the content of nitrogen is preferably no more than 1000mg/Kg, and the content of phosphorus is preferably no more than 80mg/Kg. The inventors It is found that the water passing rate of the packing layer is generally required to reach 25-50mm/h. If the clay content in the packing layer is too much, when the rainwater seeps down, the water passing rate of the packing layer will be significantly reduced, and the packing layer has poor permeability and affects The purification efficiency of the rain garden; and when the nitrogen content or phosphorus content in the filler layer is too high, a part of nitrogen and phosphorus elements will be released in the filler layer, which will affect the removal effect of the filler layer on nitrogen and phosphorus in the water body. In the present invention, by controlling the contents of organic matter, clay, nitrogen, and phosphorus in the filler layer to the above-mentioned contents, not only can sufficient nutrients be provided for plant growth, but also the filler layer can be ensured to have suitable water-permeability, and better nitrogen and phosphorus removal effect can be achieved. . According to another specific embodiment of the present invention, the geotextile layer 140 mainly plays the role of isolating the packing layer 130 and the supporting layer 150, so as to avoid seepage of the filling to the supporting layer. High-tenacity polypropylene filaments are used as the geotextile layer, which can achieve better water-permeable and sand-impermeable effects.

According to another specific embodiment of the present invention, the supporting layer 150 mainly plays the role of supporting and draining, which can prevent the loss of other fillers and also play the role of rapid drainage. Specifically, the supporting layer 150 in the present invention It can be a gravel layer, the particle size of the gravel can be 10-20mm, and the thickness of the supporting layer can be 200-300mm, so that not only can achieve better supporting effect, but also not affect the drainage effect. In addition, in the rain garden, an outlet pipe may be provided at the bottom of the drainage layer 160, thereby preventing the water from the rain garden from entering the groundwater directly.

Landscape Fountain 200

According to an embodiment of the present invention, the landscape fountain 200 includes a fountain pool 210, and the fountain pool 210 is provided with a disinfection layer 211, a water storage layer 212, and a fountain layer 213 in sequence from bottom to top, wherein a settlement tank 220 is provided at the bottom of the fountain pool; Layer 211 is provided with ultraviolet lamp tube 230, and disinfection layer 211 is connected with drainage layer 160, preferably makes fountain pool 210 and packing layer 130 form the connector structure; The water in 212 is supplied to the fountain water pipe 250 and sprayed at the fountain layer 213, and the sprayed water returns to the water storage layer 212; the upper part of the fountain layer 213 is provided with a water outlet 260, and the water outlet 260 is connected to the municipal drainage pipe. In the present invention, by using ultraviolet light tubes to disinfect the rainwater garden outlet water, the outlet water can meet the water quality requirements of landscape water, and the combined use of landscape fountains and rainwater gardens can not only improve the efficiency of the entire treatment system, but also alleviate the pollution of urban landscape in China. The difficulty of replenishing water sources and the pressure of municipal drainage; and, the water in the water reservoir of the fountain pool forms a fountain through the action of the submersible pump for viewing, and then returns to the water storage layer for recycling, which can make the water in the fountain pool be in a dynamic cycle , to ensure the content of dissolved oxygen in the water body, and reduce the risk of secondary pollution caused by water quality deterioration; in addition, by forming a connector structure between the fountain pool and the filling layer, part of the filling layer of the rain garden can be submerged, forming an anaerobic zone, thereby Contribute to the growth and reproduction of denitrifying microorganisms, and provide more favorable conditions for the removal of nitrogen in rainfall runoff; and setting the water outlet on the upper part of the fountain layer to connect with the municipal drainage pipe can not only make the rain garden water as much as possible for the landscape The fountain can also avoid the overflow of water in the fountain pool due to excessive rainfall.

According to a specific embodiment of the present invention, the ultraviolet lamp tubes 230 can be arranged side by side along the length direction of the disinfection layer 211, for example, they can be arranged side by side horizontally or vertically, and the distance between two adjacent ultraviolet lamp tubes can be 20-30 cm. In the present invention, by adopting the above arrangement, it can ensure that the water in the disinfection layer can be fully irradiated by the ultraviolet lamp, thereby further improving the disinfection effect and avoiding secondary pollution caused by deterioration of water quality. It should be noted that the longitudinal direction of the disinfection layer described in the present invention is based on the longitudinal direction shown in FIG. 1 .

According to another specific embodiment of the present invention, the settling tank 220 can further settle the sand that may exist in the effluent water of the rain garden, and keep the water body in the landscape fountain clear; in addition, the lower part of the settling tank 220 can further include a sand outlet (not shown) ), so that the sediment in the settling tank can be regularly removed through the sand outlet.

According to yet another specific embodiment of the present invention, the general principles for setting the volume of the fountain pool 210 include: 1. Collect as much water from the rain garden as possible, and avoid discharging the treated rainwater into the municipal drainage pipe network as much as possible; 2. Simplify the design of fountain pools and reduce maintenance and operation costs. Among them, the volume of the fountain pool can be:

V=Ψh _m aK,

Among them, in the formula, V- is the volume of the fountain pool, m ³ ; Ψ- is the rainfall runoff coefficient; h _m - is the design rainfall intensity corresponding to the annual total runoff control rate of 80% to 85%, mm; a- is the rain garden Land area, hm ² ; K- is the ratio of rain garden service area to land area, and the range of K is 10-20. As a result, not only can the water from the rain garden be fully used for landscape fountains as much as possible, reducing the pressure on municipal drainage, but also further reducing the maintenance and operation costs of fountain pools. It should be noted that, in the present invention, the service area of the rain garden includes the area of the catchment area of the rain garden and the floor area of the rain garden, and the floor area of the rain garden is 5-10% of the catchment area; in addition, h _m It can be the design rainfall intensity corresponding to the annual total runoff control rate of 80%, 81%, 82%, 83%, 84% or 85%.

According to an embodiment of the present invention, when it rains, the rainfall runoff of the catchment area around the rain garden enters the rain garden part through the gutter or other facilities, and the pollutants (suspended solids, COD _Cr , ammonia nitrogen and total phosphorus) carried in the rainfall runoff Purified by the cover layer, vegetation layer, filler layer, geotextile layer, supporting layer and water outlet layer in the rain garden, and then enters the disinfection layer of the fountain pool, and is disinfected under the action of ultraviolet lamps to make the water reach the level of landscape water. According to the water quality requirements, it gradually enters the water storage layer of the fountain pool, and the water in the water storage layer forms a fountain through the action of the submersible pump for viewing, and finally returns to the water storage layer for recycling.

In summary, the rainwater purification and reuse bioretention system of the above-mentioned embodiment of the present invention has at least the following advantages: 1. Using the surplus sludge from the waterworks in the filling layer of the rain garden will not only not affect the growth of plants, but also make the The filling layer has a good and long-lasting dephosphorization effect; 2. There is no need to set up a separate planting soil layer. By mixing soil, river sand, peat soil, zeolite, vermiculite and residual sludge from waterworks as the filling layer, it can meet the needs of plants. It can also effectively remove pollutants such as suspended solids, ammonia nitrogen and phosphorus in rainfall runoff. Among them, after rainwater runoff is purified by rain gardens, the removal rate of suspended solids can reach more than 85%, and the removal rate of phosphorus can reach more than 93%. . The removal rate of ammonia nitrogen can reach 65-90%, and COD _Cr can be reduced by 65-85%. 3. By using ultraviolet lamps to disinfect the effluent of the rain garden, the effluent can meet the water quality requirements of landscape water, and then it can be used for The landscape fountain can not only improve the comprehensive benefits of the entire treatment system, but also alleviate the difficulty of replenishing water sources for urban landscape water bodies and the pressure of municipal drainage; Returning to the water storage layer for recycling can make the water in the fountain pool be in a dynamic cycle, ensure the dissolved oxygen content in the water body, and reduce the risk of secondary pollution caused by water quality deterioration; 5. By forming a connector structure between the fountain pool and the packing layer , it can also make part of the filling layer of the rain garden submerged, forming an anaerobic zone, which is conducive to the growth and reproduction of denitrifying microorganisms, and provides more favorable conditions for removing nitrogen in rainfall runoff; 6. As much as possible The water from the rain garden is fully used for landscape fountains to reduce the pressure on municipal drainage.

The present invention will be described below with reference to specific embodiments. It should be noted that these embodiments are only illustrative and do not limit the present invention in any way.

Example 1

Three kinds of packing layers with different compositions were designed, and artificial rainfall was simulated to evaluate the purification effect of the packing layers. Among them, the thickness of the filler layer is 600mm, and the filler layer is composed of natural bag, zeolite, vermiculite and residual sludge from waterworks, wherein the natural bag is soil, river sand and peat soil with a mass ratio of 46:36:18. Among them, the mass ratio of natural bag, zeolite, vermiculite and dry sludge from waterworks in the packing layer, the concentration of suspended solids, COD _Cr , ammonia nitrogen and total phosphorus in the rainfall, and the removal rate of each pollutant are shown in Table 1.

Table 1 Effects of filler layers with different compositions on the removal of pollutants in rainfall

It can be seen from Table 1 that the removal rate of phosphorus in rainfall is higher when there is more residual sludge from waterworks in the fill layer.

In the description of this specification, descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

Claims (10)

1. a kind of rainwater purification recycling biological gaseous-waste holdup system characterized by comprising

Rain Garden, the Rain Garden successively include vegetable layer, coating, packing layer, geotextile layer, supporting layer from top to bottom And drainage blanket, wherein planting forms the vegetable layer, the filler in described filler layer and above the coating Layer includes nature packet, zeolite, vermiculite and waterworks excess sludge, and the packet naturally includes soil, river sand and turfy soil, described Coating includes wooden unit and bark；

Fountain sight, the fountain sight include fountain basin, the fountain basin be provided, in sequence from bottom to top, with sterilizing layer, reservoir bed and Fountain layer, wherein the fountain bottom of pond portion is equipped with subsider；The sterilizing layer is equipped with ultraviolet lamp tube, and the sterilizing layer and institute Drainage blanket is stated to be connected；The reservoir bed is equipped with immersible pump, and the immersible pump supplies the water in the reservoir bed to fountain water pipe In and spray in the fountain layer, the water of ejection is back in the reservoir bed；Fountain layer top is equipped with water outlet, described Water outlet is connected with municipal drain.

2. system according to claim 1, which is characterized in that the waterworks excess sludge is dehydration dewatered sludge, institute The mass ratio for stating nature packet, the zeolite, the vermiculite and the dehydration dewatered sludge is (50~70): (5~20): (5~20): (10~30), the mass ratio of the soil, the river sand and the turfy soil are (40~50): (30~40): (10~20).

3. system according to claim 1 or 2, which is characterized in that the partial size of the soil is not more than 0.5mm, the river Husky partial size is 0.06~0.5mm, and the partial size of the turfy soil is not more than 5mm, and the partial size of the vermiculite is 0.01~0.06mm, The partial size of the zeolite is 5~10mm, and the partial size of the dehydration dewatered sludge is not more than 0.5mm.

4. system according to claim 3, which is characterized in that the content of organic matter is 3~5wt%, sticks in described filler layer Native content is not more than 80mg/Kg no more than 1000mg/Kg, phosphorus content no more than 5wt%, nitrogen content.

5. system according to claim 1 or 4, which is characterized in that the coating with a thickness of 50~100mm, it is described Packing layer with a thickness of 500~800mm, the supporting layer with a thickness of 200~300mm.

6. system according to claim 5, which is characterized in that the supporting layer is gravel layer, and the partial size of the gravel is 10~20mm.

7. system according to claim 1 or 6, which is characterized in that the geotextile layer is nonwoven polypropylene long filament geotechnique Layer of cloth.

8. system according to claim 7, which is characterized in that the plant be selected from honeysuckle, short raw crape myrtle, Abelia biflora, False indigo, Chinese pennisetum, blue fescue grass, alkali is fluffy, at least one of Phlox paniculata L and Ma Lian.

9. system according to claim 1 or 8, which is characterized in that the ultraviolet lamp tube is along the length side of the sterilizing layer To being arranged side by side, the spacing of adjacent two ultraviolet lamp tubes is 20~30cm.

10. system according to claim 9, which is characterized in that the volume of the fountain basin are as follows:

V=Ψ h_mAK,

Wherein, V- is the fountain pool volume, m in formula³；Ψ-is rainfall runoff coefficient；h_mIt is annual flow overall control rate is 80 ~85% corresponding design rainfall intensity, mm；A- is the Rain Garden occupied area, hm²；K- is the Rain Garden service The ratio of area and its occupied area, the value range of K are 10~20.