CN112854405B

CN112854405B - Multifunctional biological detention pond and construction method thereof

Info

Publication number: CN112854405B
Application number: CN202110016503.8A
Authority: CN
Inventors: 刘清泉; 潘龙; 李澄; 赵苏; 张瑞斌; 周乃; 周舟; 张义勇
Original assignee: Jiangsu Long Leaping Engineering Design Co ltd
Current assignee: Jiangsu Long Leaping Engineering Design Co ltd
Priority date: 2021-01-07
Filing date: 2021-01-07
Publication date: 2022-06-14
Anticipated expiration: 2041-01-07
Also published as: CN112854405A

Abstract

The invention provides a multifunctional bioretention pond and a construction method thereof, wherein the bioretention pond comprises a planting soil layer, a sand layer, a gravel layer and a drainage pipe culvert, wherein the planting soil layer, the sand layer, the gravel layer and the drainage pipe culvert are sequentially arranged from top to bottom; the drainage pipe culvert is embedded in the gravel layer in the middle, and the top of the overflow device penetrates through the sand layer and the planting soil layer; the bottom of the overflow device is connected with the drainage pipe culvert; the overflow device comprises a top cap, an inner pipe, a supporting rod, an outer sleeve, a primary collecting pipe and a secondary collecting pipe; the bioretention pond provided by the invention can be prefabricated and assembled, is simple and rapid in site construction, is time-saving and labor-saving in maintenance, improves the air permeability and the permeability of soil, can purify seepage rainwater and partial over-standard rainwater, can rapidly discharge excessive rainwater, and can be used for constructing landscapes with different styles by virtue of unique appearance structures, so that the bioretention pond can be used for municipal roads, parks, buildings and residential areas.

Description

Multifunctional biological detention pond and construction method thereof

Technical Field

The invention relates to the technical field of sponge city construction, in particular to a multifunctional bioretention pond and a construction method thereof.

Background

Since the 21 st century, along with the continuous and rapid development of economy, the urbanization development of China also makes great progress. However, the natural surface of the city is replaced by the impervious hard material in the living area, so that the landform structure of the surface is changed, the natural ecological environment is badly influenced, and the problems of city flood disasters, ecological environment deterioration and the like are increasingly highlighted. Based on the above, the construction of the sponge city is an important measure for solving the current coexistence of drought and waterlogging, serious non-point source pollution, ecological environment deterioration dilemma and the construction of an ecological rainwater management system. The biological detention pond is one of important technical means of sponge cities and is positioned in the middle link of a rainwater treatment chain of the sponge cities.

The main structure of the bioretention pond consists of a water storage layer, a planting soil layer, a sand layer and a drainage layer, wherein local soil is usually adopted as planting soil, the air permeability and permeability effects are poor, and rainwater cannot be purified and flow out quickly; the commonly used bioretention pond is generally provided with only one large overflow port, excessive rainwater is intensively released, the drainage speed is slow, effective purification cannot be achieved, the construction time of overflow well concrete with a large caliber is long, the engineering implementation is complex, and the economical efficiency is poor; the larger overflow port can not create unique landscape and can not be matched with surrounding buildings or landscapes.

Disclosure of Invention

The invention aims to provide a multifunctional bioretention pond and a construction method thereof, the bioretention pond can be prefabricated and assembled, the site construction is simple and rapid, the maintenance is time-saving and labor-saving, the soil permeability and the permeability are improved, the multi-overflow port arrangement can purify seepage rainwater and partial over-standard rainwater, can rapidly discharge excessive rainwater, and meanwhile, the unique appearance structure creates landscape with other styles, and can be used for municipal roads, parks, buildings and residential areas.

In order to achieve the above object, the present invention provides a multifunctional bioretention pond, comprising:

a planting soil layer, a sand layer and a gravel layer are sequentially arranged from top to bottom,

the drainage pipe culvert comprises an outer wall, a water outlet and a seepage pipe; the drainage pipe culvert is embedded in the gravel layer in the middle;

the bottom of the overflow device is connected with the drainage pipe culvert, and the top of the overflow device penetrates through the sand layer and the planting soil layer; the overflow device comprises a top cap, an inner pipe, a supporting pipe, an outer sleeve, a primary collecting pipe and a secondary collecting pipe; the bottom of the top cap is provided with a grid, the inner pipe penetrates through the grid and is connected with the top cap through the supporting rod, the outer sleeve is wrapped on the outer wall of the inner pipe, the primary collecting pipe is vertically connected with the secondary collecting pipe, the secondary collecting pipe is vertically connected with the inner pipe, and rainwater collected by the inner pipe can flow to the primary collecting pipe through the secondary collecting pipe;

the water outlet is connected with a municipal rainwater pipe network or a rainwater collecting and recycling device;

the infiltration pipe is followed by many straight tubes that have the infiltration hole the outer wall symmetric arrangement, one end runs through the outer wall, and the other end extends to the side slope of biological detention pond both sides.

The secondary collecting pipes are symmetrically arranged at two sides of the primary collecting pipe, are arranged in the rubble layer and are positioned above the infiltration pipe, and one end of the primary collecting pipe penetrates through the outer wall and enters the inside of the drainage pipe culvert;

the outer tube runs through plant the soil layer, inner tube length is greater than the outer tube, inner tube one end stretches out and plants the soil layer top layer, and the other end extends in the metalling.

Further, the planting soil layer is composed of clay, sandy loam, corn stalks and aluminum sludge, wherein the clay, the sandy loam, the corn stalks and the aluminum sludge are in a volume ratio of 60-80 parts, 30-50 parts, 0-5 parts and 0-5 parts;

the clay has a particle size of 0.8-2.5 mm;

the particle size of the aluminum sludge filler is 1-3 mm.

Furthermore, the diameter of the sand grain diameter of the sand layer is 0.4-1mm, and the thickness of the sand layer is 100-120 mm.

Furthermore, the diameter of the gravel particles of the gravel layer is 20-40mm, the thickness of the gravel layer is 250-300mm, and the gravel layer and the sand layer are separated by a permeable geotextile.

Furthermore, the outer wall is made of reinforced concrete and can be in a cuboid shape or a cylindrical shape.

Furthermore, the diameter of the grid hole is 5-10mm, and the middle part of the grid hole is a round opening larger than the outer diameter of the inner pipe.

Furthermore, the top cap, the grating, the supporting rod, the inner pipe, the outer sleeve, the secondary collecting pipe and the primary collecting pipe are all made of PP materials.

Furthermore, the inner pipe and the outer sleeve are both cylinders with openings at the upper ends and closed lower ends and are provided with water seepage holes, and the inner diameter of the outer sleeve is 1.2-1.5 times of the outer diameter of the inner pipe.

Furthermore, the outer wall of the outer sleeve is provided with water seepage holes, the inside of the outer sleeve is filled with a mixture of slag and coal slag with the grain diameter of 0.1-0.5mm, and the hole diameters of the water seepage holes on the outer wall and the bottom of the outer sleeve are smaller than the grain diameter of the filler; the overflow means may be provided as a first overflow means and a second overflow means, the second overflow means being higher than the first overflow means, the inner tube in the first overflow means being filled with bulk zeolite, the inner tube in the second overflow means being free of filling.

Another object of the present invention is to provide a construction method of a multifunctional bioretention pond for constructing a bioretention pond, following the principle of construction from bottom to top, first underground and then on the ground, comprising the steps of:

step one, adopting a top-down gradient increasing excavation method to carry out slope releasing excavation, carrying out foundation compaction treatment after excavation is finished, controlling the compaction degree to be more than 95%, and making anti-seepage measures;

step two, firstly, constructing the drainage pipe culvert at the middle part of the bottom, reserving the infiltration pipe connector and the primary collection pipe connector, then laying a layer of gravel below the infiltration pipe reserved connector, installing and connecting the infiltration pipes, laying a layer of gravel to the primary collection pipe reserved connector after the infiltration pipe is finished, and installing and connecting the overflow device, wherein the upper end of the inner pipe is required to reach the design height;

step three, temporarily fixing the overflow device, then paving the gravels to a set thickness, and sequentially paving the permeable geotextile and the sand layer on the top of the gravel layer;

filling corresponding fillers into the outer sleeve and the inner pipe of the first overflow device, and then laying the planting soil layer until the design height is reached, wherein the inner pipe is partially exposed out of the soil surface;

and fifthly, pre-mixing the soil layer before the planting soil layer is laid, configuring 60-80 parts of clay, 30-50 parts of sandy loam, 0-5 parts of corn stalk and 0-5 parts of aluminum sludge according to the volume ratio, performing a pre-experiment to determine the virtual laying thickness, compacting, and finally planting flooding-resistant and drought-resistant aquatic plants.

According to the technical scheme, the multifunctional bioretention pond and the construction method thereof provided by the technical scheme of the invention have the following beneficial effects:

(1) the multifunctional bioretention pond provided by the invention can be prefabricated and assembled, is simple and rapid in site construction, time-saving and labor-saving in maintenance, can effectively purify rainwater, and can be used for municipal roads, parks, buildings and residential areas;

(2) the multifunctional bioretention pond provided by the invention has the advantages that the air permeability and the permeability of soil are improved, and rainwater is more effectively purified and discharged;

(3) the multifunctional bioretention pond provided by the invention is provided with a plurality of overflow ports with different heights, can quickly discharge excessive rainwater while purifying partial excessive rainwater, and meanwhile, the unique appearance structure creates landscape with different styles, so that the multifunctional bioretention pond is novel.

It should be understood that all combinations of the foregoing concepts and additional concepts described in greater detail below can be considered as part of the inventive subject matter of this disclosure unless such concepts are mutually inconsistent.

The foregoing and other aspects, embodiments and features of the present teachings can be more fully understood from the following description taken in conjunction with the accompanying drawings. Additional aspects of the present invention, such as features and/or advantages of exemplary embodiments, will be apparent from the description which follows, or may be learned by practice of specific embodiments in accordance with the teachings of the present invention.

Drawings

The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. Embodiments of various aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of the structure of a multifunctional bioretention pond of the present invention.

Fig. 2 is a schematic plan view of an overflow device and collection tube according to the present invention.

Fig. 3 is a schematic perspective view of an overflow device according to the present invention.

FIG. 4 is a schematic view of the top cap structure of the present invention.

In the figure, the specific meaning of each mark is:

1-planting soil layer, 2-sand layer, 3-gravel layer, 4-drainage pipe culvert, 41-outer wall, 42-water outlet, 43-seepage pipe, 5-overflow device, 51-top cap, 52-grid, 53-support rod, 54-inner pipe, 55-outer sleeve pipe, 56-secondary collection pipe, and 57-primary collection pipe.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention. Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.

The detailed working principle of the multifunctional bioretention pond of the invention will be further described in detail with reference to the embodiment shown in the attached drawings.

Referring to fig. 1, the multifunctional bioretention pond is provided with a planting soil layer 1, a sand layer 2, a crushed stone layer 3 and a drainage pipe culvert 3 from top to bottom in sequence, wherein the drainage pipe culvert 3 comprises an outer wall 41, a water outlet 42 and a seepage pipe 43; the drain culvert 3 is embedded centrally inside the gravel layer 3.

Referring to fig. 1-4, the bottom of the overflow device 5 is connected with the drain culvert 4, and the top of the overflow device 4 passes through the sand layer 2 and the planting soil layer 1.

The overflow device 5 comprises a top cap 51, an inner pipe 54, a support rod 53, an outer sleeve 55, a primary collecting pipe 57 and a secondary collecting pipe 56; the bottom of the top cap 51 is provided with a grid 52, an inner pipe 54 penetrates through the grid 52 and is connected with the top cap through a support rod 53, an outer sleeve 55 wraps the outer wall of the inner pipe 54, a primary collecting pipe 57 is vertically connected with a secondary collecting pipe 56, the secondary collecting pipe 56 is vertically connected with the inner pipe 54, and rainwater collected by the inner pipe 54 can flow to the primary collecting pipe 57 through the secondary collecting pipe 56.

The infiltration pipe 43 is arranged along the outer wall 41 by many straight pipes with infiltration hole symmetrically, and one end runs through the outer wall 41, and the other end extends to the side slope of biological detention pond both sides.

The water outlet 42 is connected with a municipal rainwater pipe network or a rainwater collecting and recycling device.

The second-level collecting pipes 56 are symmetrically arranged on two sides of the first-level collecting pipe 57 and are arranged in the lithosphere 3 and located above the infiltration pipe, and one end of the first-level collecting pipe 57 penetrates through the outer wall 41 and enters the interior of the drainage pipe culvert 4.

The outer sleeve 55 runs through the planting soil layer 1, the length of the inner tube 54 is larger than that of the outer sleeve 55, one end of the inner tube 54 extends out of the surface layer of the planting soil layer, and the other end of the inner tube extends into the gravel layer. The multifunctional bioretention pond can be prefabricated and assembled, is simple and quick in site construction, time-saving and labor-saving in maintenance, can effectively purify rainwater, and can be used for municipal roads, parks, buildings and residential areas; the air permeability and the permeability of the soil are improved, and rainwater is purified and discharged more effectively; the multifunctional bioretention pond is provided with a plurality of overflow ports with different heights, can quickly discharge excessive rainwater when purifying partial excessive rainwater, and simultaneously creates landscape with different styles by unique appearance structure, thus being novel.

Further, the planting soil layer 1 is composed of clay, sandy loam, corn stalks and aluminum sludge, wherein the clay, the sandy loam, the corn stalks and the aluminum sludge are in a volume ratio of 60-80 parts, 30-50 parts, 0-5 parts and 0-5 parts. The particle size of clay is 0.8-2.5 mm's granule, the particle size of aluminium sludge filler is 1-3 mm's granule, and the cornstalk is through smashing many times back and clay, sandy loam, the doping of aluminium sludge until misce bene, and the planting soil gas permeability and the permeability that obtain are better, and the addition of aluminium sludge and cornstalk can improve biological detention pond nitrogen and phosphorus removal effect. The height of the surface layer of the planting soil layer 1 from the water inlet of the bioretention pond is the height of the water storage layer.

Emergent aquatic plants are planted on the surface layer of the planting soil layer 1, the planted plants need to meet the requirements of drought resistance, waterlogging resistance, easy growth and hydrologic conditions of the location of the device, and preferably one or more of calamus, calamus flavus, thalictrum, iris, oriental cattail and allium fistulosum.

Furthermore, the diameter of the sand grain diameter of the sand layer 2 is 0.4-1mm, and the thickness of the sand layer 2 is 100-120 mm. So as to achieve the biological retention purification and the balance of water.

Furthermore, the diameter of the gravel particles of the gravel layer 3 is 20-40mm, the thickness is 250-300mm, and the gravel layer 3 and the sand layer 2 are separated by a permeable geotextile. The gravel layer and the sand layer are separated by the permeable geotextile and the water permeability is ensured, the soil in the planting soil area and the sand in the sand layer are prevented from running off, and the infiltration pipe 43 is not blocked. The crushed stone layer 3 has double functions of purifying rainwater and distributing water uniformly.

Further, the outer wall 41 is made of reinforced concrete, and may be a rectangular parallelepiped or a cylinder. Has certain compressive strength. The water outlet 42 is connected with a municipal rainwater pipe network or a rainwater collecting and recycling device to discharge the purified water out of the multifunctional bioretention pond.

Furthermore, the diameter of the grid hole of the grid 52 is 5-10mm, and the middle part is a round opening larger than the outer diameter of the inner pipe. Thereby facilitating passage of the inner tube 54 therethrough. The grating 52 can block large floating impurities from entering the inner pipe 54.

Further, the top cap 51, the grating 52, the support rod 53, the inner tube 54, the outer sleeve 55, the secondary collection tube 56 and the primary collection tube 57 are all made of PP. The pp material is polypropylene which is a non-toxic, odorless and tasteless milky high-crystallinity polymer and is stable to water and good in formability. All parts are made of PP materials, and the structure is simple and the cost is low. The inner pipe 54 is connected with the secondary collecting pipe 56 through an elbow or a tee joint, the secondary collecting pipe 56 is connected with the primary collecting pipe 57 through hot melting, the inner pipe 54 is connected with the outer sleeve 55 through hot melting, and the support rod 53 is connected with the top cap 51 and the inner pipe 54 through hot melting.

Further, the inner tube 54 and the outer sleeve 55 are both cylinders with open upper ends and closed lower ends and provided with water seepage holes, and the inner diameter of the outer sleeve 55 is 1.2-1.5 times of the outer diameter of the inner tube 54. Furthermore, the outer wall of the outer sleeve 55 is provided with water seepage holes, the inside of the outer sleeve is filled with a mixture of slag and coal slag with the grain diameter of 0.1-0.5mm, and the hole diameters of the water seepage holes on the outer wall and the bottom of the outer sleeve are smaller than the grain diameter of the filler; the mixture of the slag and the coal cinder can improve the air permeability and the permeability of the planting soil layer 1, so that rainwater can be discharged and purified more quickly; the overflow means 5 may be provided as a first overflow means and a second overflow means which is higher than the first overflow means, preferably half of the overflow means 5, i.e. the inner tube 54 of the first overflow means, having its upper port at the aquifer level 2/3, and the other half of the overflow means 5, i.e. the inner tube 54 of the second overflow means, having its upper port at the upper aquifer level. The inner pipe 54 of the first overflow device at a lower position is filled with large-sized zeolite, and gaps among the filling materials are large, so that rainwater can rapidly pass through.

The operation of the bioretention tanks shown in the examples is described in detail below. When the rainfall is small, the bioretention pond can absorb all the rainwater, the rainwater enters the bioretention pond from the water inlet and sequentially passes through the planting soil layer 1 and the sand layer 2, and effective filtration and purification are achieved; through the even water distribution of the gravel layer 3, rainwater enters the infiltration pipe 43 through the seepage hole, converges to the inside of the drainage culvert 4 and is discharged from the water outlet 42; when the rainfall is large, the inflow speed of rainwater is greater than the permeation rate, the bioretention pond cannot immediately absorb the rainwater, the rainwater starts to accumulate on the surface layer of the planting soil layer 1, when the water level gradually rises to the overflow device 5 at the lower position, the rainwater enters the inner pipe 54 through the primary filtration of the grating 52, is filtered and purified through the zeolite filled in the inner pipe 54 and is collected into the secondary collection pipe 56, the collected rainwater is further collected into the primary collection pipe 57 by the secondary collection pipe 56, and finally is collected into the drainage pipe culvert 4 and is discharged from the water outlet 42; when the rainwater is exposed to heavy rain, the water level of the aquifer rises rapidly, the rainwater submerges the overflow device 5 at the lower position, namely the first overflow device, part of the rainwater exceeding the standard is purified, but more rainwater can flow into the overflow device 5 at the higher position, namely the second overflow device, and the rainwater can enter the drainage pipe culvert through the secondary collecting pipe 56 and the primary collecting pipe 57 quickly and is discharged rapidly from the water outlet 42 because the inner pipe 54 of the second overflow device is not filled with filler.

The application provides a construction method of a multifunctional bioretention pond, which is used for building the bioretention pond and follows the construction principle from bottom to top, firstly underground and then on the ground, and comprises the following steps:

step two, firstly, constructing a drainage pipe culvert 4 at the middle part of the bottom, reserving an interface of a seepage pipe 43 and an interface of a primary collecting pipe 57, then laying a layer of crushed stone below the reserved interface of the seepage pipe 43, installing and connecting the seepage pipe 43, then laying a layer of crushed stone to the reserved interface of the primary collecting pipe 57, installing and connecting an overflow device 5, and enabling the upper end of an inner pipe 54 to reach a design height;

step three, temporarily fixing the overflow device 5, then paving the gravels to a set thickness, and sequentially paving the permeable geotextile and the sand layer 2 on the top of the gravel layer 3;

filling corresponding fillers into the outer sleeve 55 and the inner pipe 54 of the first overflow device, and then laying the planting soil layer 1 until the design height is reached, wherein the inner pipe 54 has a certain length and is exposed out of the soil surface;

fifthly, pre-mixing is carried out before the planting soil layer 1 is laid, and the clay, the sandy loam, the corn stalks and the aluminum sludge are prepared according to the proportion, wherein the volume ratio of the clay, the sandy loam, the corn stalks and the aluminum sludge is 60-80 parts, 30-50 parts, 0-5 parts and 0-5 parts; preferably, 70 parts of clay, 40 parts of sandy loam, 3 parts of cornstalks and 3 parts of aluminum sludge are selected, pre-experiments are carried out to determine parameters such as virtual paving thickness and the like, compaction is carried out, and finally, flooding-resistant and drought-resistant aquatic plants are planted.

The construction method of the multifunctional bioretention pond provided by the invention can be adopted for prefabricating and assembling, is simple and rapid in site construction, time-saving and labor-saving in maintenance, can effectively purify rainwater, and can be used for municipal roads, parks, buildings and residential areas; the multifunctional bioretention pond provided by the invention can improve the air permeability and permeability of soil and purify and discharge rainwater more effectively; the multifunctional bioretention pond provided by the invention is provided with a plurality of overflow ports with different heights, can quickly discharge excessive rainwater while purifying partial excessive rainwater, and meanwhile, the unique appearance structure creates landscape with different styles, so that the multifunctional bioretention pond is novel.

The biological retention tank shown in the attached figure is tested by application of suspended matters (SS), Chemical Oxygen Demand (COD), Total Phosphorus (TP) and ammonia Nitrogen (NH)₃-N) is an evaluation index, and the test result shows that the bioretention pond disclosed by the invention can be used for treating Suspended Substances (SS), Chemical Oxygen Demand (COD), Total Phosphorus (TP) and ammonia Nitrogen (NH) in rainwater₃-N) is 90.36%, 66.83%, 89.32% and 85.58% respectively, and the purification effect is remarkable.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A construction method of a multifunctional bioretention pond is characterized in that the multifunctional bioretention pond comprises the following steps:

a planting soil layer, a sand layer and a crushed stone layer are sequentially arranged from top to bottom;

the bottom of the overflow device is connected with the drainage pipe culvert, and the top of the overflow device penetrates through the sand layer and the planting soil layer; the overflow device comprises a top cap, an inner pipe, a supporting rod, an outer sleeve, a primary collecting pipe and a secondary collecting pipe; the bottom of the top cap is provided with a grid, the inner pipe penetrates through the grid and is connected with the top cap by using the supporting rod, the outer sleeve is wrapped on the outer wall of the inner pipe, the primary collecting pipe is vertically connected with a secondary collecting pipe, the secondary collecting pipe is vertically connected with the inner pipe, and rainwater collected by the inner pipe can flow to the primary collecting pipe through the secondary collecting pipe;

the seepage pipe is formed by symmetrically arranging a plurality of straight pipes with seepage holes along the outer wall, one end of the seepage pipe penetrates through the outer wall, and the other end of the seepage pipe extends to the side slopes on two sides of the bioretention pond;

the outer sleeve penetrates through the planting soil layer, the length of the inner pipe is larger than that of the outer sleeve, one end of the inner pipe extends out of the surface layer of the planting soil layer, and the other end of the inner pipe extends into the gravel layer;

the construction method of the multifunctional bioretention pond comprises the following steps: step one, adopting a top-down gradient increasing excavation method to carry out slope releasing excavation, carrying out foundation compaction treatment after excavation is finished, controlling the compaction degree to be more than 95%, and making anti-seepage measures;

2. A multifunctional bioretention pond constructed by the method of claim 1; the clay has a particle size of 0.8-2.5 mm; the particle size of the aluminum sludge filler is 1-3 mm.

3. The multifunctional bioretention pond of claim 2 wherein the sand layer has a sand grain diameter of 0.4-1mm and a thickness of 100-120 mm.

4. The multifunctional bioretention pond of claim 3 wherein the crushed stone layer has crushed stone particles of 20-40mm diameter and 250-300mm thickness and is separated from the sand layer by a water permeable geotextile.

5. The multifunctional bioretention pond of claim 2 wherein the outer wall is made of reinforced concrete and is of a rectangular parallelepiped or cylindrical shape.

6. The multifunctional bioretention pond according to claim 2 wherein the diameter of the grating holes is 5-10mm and the middle part is a round mouth larger than the outer diameter of the inner pipe.

7. The multifunctional bioretention pond of claim 2 wherein the top cap, the grid, the support rods, the inner tube, the outer sleeve, the secondary collection tubes and the primary collection tubes are all PP.

8. The multifunctional bioretention pond of claim 2 wherein the inner tube and the outer sleeve are each a cylinder open at the upper end and closed at the lower end with weep holes and the outer sleeve has an inner diameter 1.2-1.5 times the outer diameter of the inner tube.

9. The multifunctional bioretention pond according to claim 8, wherein the outer wall of the outer sleeve is provided with water seepage holes, the inside of the outer sleeve is filled with a mixture of slag and coal slag with a grain diameter of 0.1-0.5mm, and the pore diameters of the water seepage holes on the outer wall and the bottom of the outer sleeve are smaller than the grain diameter of the filler; the overflow device can be a first overflow device and a second overflow device, the second overflow device is higher than the first overflow device, the inner pipe in the first overflow device is filled with large zeolite, and the inner pipe in the second overflow device is free from filling.