CN117228850A - Plain river network bank pollution interception system - Google Patents

Abstract

The invention discloses a plain river network slope bank pollution interception system, which belongs to the technical field of ecological engineering. The system consists of multi-level strip-shaped ecological interception units parallel to the river bankline, which are laid out from top to bottom along the slope. The ecological interception units include fillers, planting soil, plants, water distribution pipes, water collection pipes and water outlet verticals. The units are connected by connecting pipes. The system adopts side water inflow, underflow, and reentrant water inlet methods. The water flow flows horizontally and horizontally from the water distribution pipe along the first-level ecological interception unit, and returns to the second-level ecological interception unit through the water collection pipe, outlet vertical pipe, connecting pipe, and water distribution pipe. Until it is discharged into the receiving water body. This invention aims at the lack of flat land indicators in plain river network areas and the characteristics of long-term acceptance of a large amount of agricultural non-point source pollution. It makes full use of the river slopes, builds a slope bank pollution interception system according to local conditions, and intercepts and purifies agricultural non-point source pollution on the spot. It can be widely used in farmland drainage, aquaculture wastewater, rural sewage treatment station tailwater, etc. to ensure the water quality of plain river networks.

Description

A pollution interception system for slope banks of plain river networks

Technical field

The invention belongs to the technical field of ecological engineering and relates to a pollution interception system on slopes of plain river networks.

Background technique

The plain river network areas are economically developed and urbanization and industrialization are developing rapidly. Human activities have a greater impact on the ecological environment of the river network areas, and the water environment is becoming increasingly severe. Although point source pollution has been effectively controlled, production activities such as planting (dry fields, paddy fields), breeding (aquaculture, livestock and poultry breeding), etc. generate a large amount of farmland water withdrawal, breeding wastewater, and rural sewage treatment station tailwater into the river for a long time. , lakes (reservoirs) and other receiving water bodies, exacerbating the difficulty of controlling non-point source pollution, making it difficult for the water quality of river networks to meet increasingly stringent water quality standards. Among them, nitrogen and phosphorus nutrients are the key targets of agricultural non-point source pollution control. Reducing the nitrogen and phosphorus load into rivers and lakes (reservoirs) is the key to limiting eutrophication of water bodies and improving the health of water ecology.

The terrain of the river network area is flat, the water flow rate is slow, the self-purification ability of the water body is poor, and pollutants are easy to accumulate. Therefore, before agricultural non-point source pollution enters the receiving water body, establishing an ecological interception system to block nitrogen, phosphorus and other pollutants from entering the river water body is an important technical means to ensure the water quality of the river network. However, due to restrictions on land use indicators, plain river network areas often lack flat land space, leaving only river slopes available for use. Typical ecological interception systems, such as constructed wetlands, have strict requirements on land flatness, thus limiting their application on river bank slopes. Although patent disclosures CN 105198085A and CN 102531294A break through the restrictions of slope terrain and build a multi-level stepped subsurface flow constructed wetland combination system, the bottom of each level of wetland unit needs to be flattened, which increases the difficulty and cost of construction, and changes the original The slope topography.

According to local conditions and in response to the shortage of land in river network areas, the construction of ecological bank slope systems is an important means of intercepting non-point source pollution. Carry out ecological transformation or functional enhancement on the basis of existing slope banks, use physical and chemical effects or biogeochemical processes to intercept and degrade pollutants, reduce the pollution load entering the river, and improve the water quality of the river network. Patent publication CN 102839632A constructs an ecological slope protection with hollow hexahedrons (plants planted inside) as basic components for treating non-point source pollution. However, this slope protection system only includes the planting soil layer and lacks the fill layer’s percolation, interception and adsorption purification of pollutants, so the pollution load reduction efficiency is limited. Patent CN 216106242U constructs an ecological interception zone on river and lake bank slopes. 20-60cm of ecological filler (composed of gravel or volcanic rock, ceramsite, medical stone, biochar particles and iron filings) is laid on the surface of the bank slope for enhanced denitrification. Phosphorus removal. Although the ecological fill constructed by this ecological interception zone can improve nitrogen and phosphorus removal to a certain extent, the pollutants stay for a short time from top to bottom along the slope and cannot be retained, so there is still room for improvement in water quality purification.

It is extremely necessary to innovate or integrate existing non-point source pollution control technologies to adapt to the characteristics of plain river network areas that have long received a large amount of agricultural non-point source polluted water bodies and are short of land. In particular, making full use of the river slopes, building an ecological interception system, and strengthening the nitrogen and phosphorus load reduction efficiency are the keys to ensuring the water quality of the river network and improving the health of the aquatic ecology.

Contents of the invention

The object of the present invention is to provide a plain river network slope bank pollution interception system in view of the shortcomings of the existing technology. Through the present invention, the problem that the plain river network area has long accepted a large amount of agricultural non-point source polluted water bodies and lacks flat land space and only the river slopes are available for utilization can be overcome, and the polluted water bodies can be intercepted and purified on the spot from the source, and the inflow into rivers and lakes (reservoirs) can be strengthened. ) Nitrogen and phosphorus load reduction efficiency and improve the water environment of the river network.

In order to achieve the above objects, the present invention adopts the following technical solutions:

A plain river network slope bank pollution interception system, including multi-level strip-shaped ecological interception units parallel to the river bank line. The ecological interception unit is provided with a filling layer, a planting soil layer and a planting layer along the river bank slope from bottom to top. When planting plants on the soil layer, water collection pipes and water distribution pipes are laid inside the filler layer. Multiple ecological interception units are separated by retaining walls, and the water collection pipes of the upper level ecological interception units are connected through outlet vertical pipes and The pipe is connected to the water distribution pipe of the next-level ecological interception unit; wherein the connecting pipe passes through the retaining wall.

In one embodiment of the present invention, the number of ecological interception unit levels is adjusted according to the width of the slope bank, preferably level 1-5, and more preferably level 2-5. The ecological interception units are divided into first level, second level,... from top to bottom along the slope surface.

In one embodiment of the present invention, the water collecting pipe is located at the bottom of the filling layer and is used to collect water passing through the filling layer.

In one embodiment of the present invention, the water distribution pipe is used to arrange the water collected by the water collection pipe of the upper-level ecological interception unit into the filler layer of the next-level ecological interception unit, thereby using the filler layer to further process sewage.

In one embodiment of the present invention, the water collecting pipes and water distribution pipes of the ecological interception unit at the same level are preferably placed on different sides of the packing layer; the water collecting pipes and water distribution pipes of two adjacent levels are preferably placed on the same side of the packing layer. For example, taking the north-south direction of the river as an example, if the water collection pipe of the upper-level ecological interception unit is located on the south side of the corresponding fill layer, then the water collection pipe of the next-level ecological interception unit is preferably located on the north side of the corresponding fill layer. The water distribution pipe of the ecological interception unit is preferably located on the south side of the corresponding fill layer. The purpose of this setting is to realize the return of incoming water, prolong the residence time of polluted water in the bank interception system, and improve the pollution removal efficiency.

In one embodiment of the present invention, the water distribution flow preferably flows horizontally and horizontally along the interception unit.

In one embodiment of the present invention, the plain river network slope bank pollution interception system includes a water inlet, and the water inlet is connected to the water distributor of the first-level ecological interception unit.

In one embodiment of the present invention, the ecological interception unit adopts side water inlet, underflow, and reentrant water inlet methods, that is, the polluted water body passes through the first-level ecological interception from the first-level water distribution pipe located in the first-level ecological interception unit. The transverse horizontal underflow of the unit is collected by the first-level water collection pipe located in the first-level ecological interception unit, and then passes through the first-level outlet vertical pipe, the connecting pipe connecting the first-level and second-level ecological interception units, and the second-level ecological interception unit located in the second-level ecological interception unit. The first-level water pipes return to the second-level ecological interception unit. Similarly, it continues to flow into the next level ecological interception unit and finally discharges into the receiving water body.

In an embodiment of the present invention, the retaining wall is flush with the slope.

In one embodiment of the present invention, the bottom of the ecological interception unit is treated with anti-seepage treatment.

In one embodiment of the present invention, the vertical depth of the ecological interception unit is 70-100cm.

In one embodiment of the present invention, the filler of the filler layer is selected from one or more fillers that enhance nitrogen and phosphorus removal, such as zeolite, ceramsite, pyrite, and biochar.

In one embodiment of the present invention, the depth of the planting soil layer is 10-30cm, preferably sandy soil with both penetration and water retention capabilities, and the sand ratio is 10-50%.

In one embodiment of the present invention, the first level of the ecological interception unit is planted with drought-tolerant shrub plants, such as oleander, hibiscus, amorpha, tallow tree, pyracantha, winter jasmine, privet, nandiana One or more types of bamboo; the subsequent ecological interception unit is planted with one or more types of drought-tolerant emergent hygrophytes, such as Arundo japonica, canna, philodendron, windmill grass, and iris.

In one embodiment of the present invention, the water outlet vertical pipe is higher than the bottom of the ecological interception unit, forming a stagnant water area. The depth of the stagnant water area preferably accounts for 40%-70% of the depth of the interception unit. More preferably, it can be based on Actual demand regulates the depth of the stagnant layer to 40-50cm.

In one embodiment of the present invention, the construction steps of the ecological interception unit include (a) horizontal excavation of the foundation along the slope; (b) construction of a retaining wall and anti-seepage treatment at the bottom of the unit; (c) laying out a pipe network; (d) Fill the substrate and plant plants.

The present invention also provides the application of the above-mentioned plain river network slope bank pollution interception system in the environmental field.

Compared with the prior art, the present invention has the following beneficial effects:

1. Break through the restrictions on flat land indicators in plain river network areas, make full use of river slopes, build slope bank pollution interception systems according to local conditions, intercept and purify agricultural non-point source pollution at the source, and improve the water environment of river networks;

2. The constructed multi-level ecological interception unit adopts underflow and reentrant water inlet methods to extend the residence time of polluted water in the bank interception system and improve pollution removal efficiency;

3. In view of the characteristics of agricultural non-point source pollution, fillers such as zeolite, ceramsite, pyrite, and biochar are used to improve the nitrogen and phosphorus removal capabilities and strengthen the reduction of nitrogen and phosphorus loads into rivers and lakes (reservoirs);

4. The constructed ecological interception unit contains a stagnant water layer. The internal redox environment of the slope bank pollution interception system is diverse and has a long residence time, which is conducive to denitrification;

5. The provided plain river network slope bank pollution interception system is simple to construct and low in cost. It combines sewage treatment with river landscape and has good economic, social and environmental benefits.

Description of drawings

Figure 1 is a schematic structural diagram of a pollution interception system on slopes of plain river networks in an embodiment of the present invention, taking a three-level ecological interception unit as an example.

Figure 2 is a left side view of the structure of the plain river network slope bank pollution interception system in the embodiment of the present invention.

Figure 3 is a right side view of the structure of the plain river network slope bank pollution interception system in the embodiment of the present invention.

In the figure, 1-the first water distribution pipe, 2-the second water distribution pipe, 3-the third water distribution pipe, 4-the first water collection pipe, 5-the second water collection pipe, 6-the third water collection pipe, 7-the first level -Second level connecting pipe, 8-Second level-Third level connecting pipe, 9-First water outlet vertical pipe, 10-Second water outlet vertical pipe, 11-Third water outlet vertical pipe, 12-Retaining wall, 13- Filling layer, 14-planting soil layer, 15-plants.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Example 1

One embodiment of a plain river network slope bank pollution interception system of the present invention is shown in Figure 1. It consists of three levels of strip-shaped ecological interception units parallel to the river bankline. The ecological interception units are along the slope from top to bottom. The first-level ecological interception unit, the second-level ecological interception unit, and the third-level ecological interception unit are arranged underneath to maintain the original bank slope topography. The ecological interception unit includes a filler layer (13) and a planting soil layer (14 ), plants (15), and the first water distribution pipe 1, the second water distribution pipe 2, the third water distribution pipe 3, the first water collection pipe 4, the second water collection pipe 5, the third water collection pipe 6, the first water distribution pipe located on the fill layer The first-stage-second-stage connecting pipe 7, the second-stage-third-stage connecting pipe 8, the first water outlet vertical pipe 9, the second water outlet vertical pipe 10, and the third water outlet vertical pipe 11. Among them, the first water distribution pipe 1, the first water collecting pipe 4, and the first water outlet vertical pipe 9 are located in the first-level ecological interception unit, and the second water distribution pipe 2, the second water collecting pipe 5, and the second water outlet vertical pipe 10 Located in the second-level ecological interception unit, the third water distribution pipe 3, the third water collection pipe 6, and the third water outlet vertical pipe 11 are located in the third-level ecological interception unit, and the first-level-second-level connecting pipe 7 passes through The retaining wall connects the first-level ecological interception unit and the second-level ecological interception unit, and the second-level-third-level connecting pipe 8 passes through the retaining wall to connect the second-level ecological interception unit and the third-level ecological interception unit.

Among them, the ecological interception unit is provided with a filling layer 13, a planting soil layer 14, and plants 15 planted on the planting soil layer 14 from bottom to top along the river bank slope. The ecological interception units at each level are separated by retaining walls 12. A water inlet is provided on one side of the first-level ecological interception unit. The water inlet is connected to the first water distribution pipe 1. The first water collecting pipe 4 is located on the side away from the first water distribution pipe 1 and is used to collect the first water distribution pipe 1. The water from a water distribution pipe 1 is the incoming water after being treated by the filler layer. The first water collection pipe 4 is connected to the first water outlet vertical pipe 9, the first-second level connecting pipe 7 and the second water distribution pipe 2 in sequence. The second water distribution pipe 2 is located on the same side as the first water collecting pipe 4; the second water collecting pipe 5 is located on the side away from the second water distribution pipe 2 and is used to collect the water from the second water distribution pipe 2 that has been treated by the filler layer. The second water collecting pipe 5 communicates with the second water outlet vertical pipe 10, the second-third level connecting pipe 8 and the third water distribution pipe 3 in sequence; the third water collecting pipe 6 is located at a distance away from the third water distribution pipe 3. The side is used to collect the water treated by the filler layer from the third water distribution pipe 3. The water collected by the third water collecting pipe 6 is discharged into the river through the third water outlet vertical pipe 11 and the pipes connected with the river.

In the embodiment, the ecological interception unit adopts side water inlet, underflow, and reentrant water inlet methods. As shown in Figures 1, 2, and 3, the polluted water body flows horizontally and horizontally from the first water distribution pipe 1 along the first-level ecological interception unit, through The first water collecting pipe 4, the first water outlet vertical pipe 9, the first-level connecting pipe 7 and the second water distribution pipe 2 are returned to the secondary ecological interception unit. The water flow continues to flow horizontally and flows into the third-level ecological interception unit through the second water collecting pipe 5, the second water outlet vertical pipe 10, the second-level connecting pipe 8 and the third water distribution pipe 3, and finally flows to the third water collecting pipe 6 , and is discharged into the river through the third outlet pipe 11.

In one embodiment, the vertical depth of the ecological interception unit is 70-100cm.

In one embodiment, the filler of the filler layer is selected from one or more fillers that enhance denitrification and phosphorus removal, such as zeolite, ceramsite, pyrite, and biochar.

In one embodiment, the depth of the planting soil layer is 10-30cm, preferably sandy soil with both penetration and water retention capabilities, and the sand ratio is 10-50%.

In one embodiment, the first level of the ecological interception unit is planted with drought-tolerant shrub plants, such as one of oleander, hibiscus, amorpha, tallow tree, pyracantha, winter jasmine, ligustrum, and nandina. Or more than one kind; the subsequent ecological interception unit is planted with one or more drought-tolerant emergent hygrophytes, such as Arundo japonica, Canna, Centella, windmill grass, and iris.

In one embodiment, the water outlet vertical pipe is higher than the bottom of the ecological interception unit, forming a stagnant water area. The depth of the stagnant water area preferably accounts for 40%-70% of the depth of the interception unit. More preferably, the stagnation can be adjusted according to actual needs. The depth of the water layer is 40-50cm.

In addition, the level of ecological interception units can be adjusted according to the width of the slope bank, such as level 2, level 3, level 4, level 5, etc.

Example 2

A plain river network slope bank pollution interception system is shown in Figures 1 to 3. Among them,

In the embodiment, the slope depth of the ecological interception unit is 90cm.

In the embodiment, the filling layer of the first-level ecological interception unit is filled with zeolite, and the planting soil layer is planted with the drought-tolerant shrub plant Nandina; the filling layer of the second-level ecological interception unit is filled with biochar, and the planting soil layer is planted with the drought-tolerant emergent hygrophytic plant Canna ; The filling layer of the third-level ecological interception unit is filled with ceramsite, and the planting soil layer is planted with the drought-tolerant emergent hygrophytic plant Iris.

In the embodiment, the depth of the planting soil layer is 30cm, sandy soil with both penetration and water retention capabilities is selected, and the sand ratio is 30%.

In the embodiment, the water outlet pipe is higher than the bottom of the ecological interception unit, forming a stagnant water area with a depth of 50 cm.

After testing, the average removal rates of TN and TP in the system effluent compared to the incoming water were 49.8% and 74.8% respectively. Among them, the TN and TP in the initial incoming water were 5.3-32.9mg/L and 0.29-2.72mg/L respectively.

The plain river network slope bank pollution interception system of the present invention excavates downwards along the slope to construct a sunken ecological interception unit, retains the original slope topography, does not require a pre-settlement tank, and directly enters the treatment unit through gravity flow, which is more suitable for agriculture The characteristics of non-point source pollution are "wide and scattered"; the sunken structure of the present invention has a deeper filling layer, so the redox environment along the filling layer is rich and the microbial community structure is diverse, which is more conducive to nitrogen and phosphorus removal, and can Overcome the problem that plain river network areas have long received a large amount of agricultural non-point source polluted water bodies and lack of flat land space, leaving only river slopes for use, intercept and purify polluted water bodies at the source, and strengthen the reduction of nitrogen and phosphorus loads into rivers and lakes (reservoirs) efficiency and improve the water environment of the river network.

Example 3

When the planting soil layers of the first-level, second-level and third-level ecological interception units are all planted with Acorus, the rest is the same as in Embodiment 2.

The results showed that the TN and TP removal rates of the system effluent compared to the incoming water were 42.6% and 66.4% respectively. It can be seen that the removal effect of mixed plants is better than that of planting a single plant.

Example 4

When the intercepting unit slope depths are 0.45m and 0.75m respectively, the rest is the same as in Embodiment 2.

The results found that when the slope depth of the interception unit is 0.45m, the TN and TP removal rates of the system outlet water relative to the inlet water are on average 26.7% and 64.0% respectively; when the interception unit slope depth is 0.75m, the system outlet water relative to the inlet water is 26.7% and 64.0% respectively. The TN and TP removal rates of the incoming water averaged 33.8% and 68.0% respectively.

It can be seen that the deeper the interception unit slope depth, the better. On the one hand, the contact time is prolonged, and on the other hand, the redox environment is better. Preferably, the interception unit slope depth is at least 0.75m, preferably 0.9m.

Example 5

When the heights of the stagnant areas are 0cm, 15cm, 40cm, and 60cm respectively (accounting for 0%, 16%, 44%, and 66% of the depth of the interception unit respectively), the rest is the same as in Example 2.

The results showed that when the height of the stagnant water area is 0cm, the average TN removal rate is 22.0%; when the height of the stagnant water area is 15cm, the average TN removal rate is 32.0%; when the height of the stagnant water area is 40cm, the TN removal rate is 32.0%. The average removal rate is 39.7%; when the height of the stagnant water zone is 60cm, the average TN removal rate is 49.1%.

It can be seen that setting up a stagnant water area has a better removal effect, especially nitrogen removal. In addition, in order to avoid overflow due to heavy rain, the water retention depth cannot be too deep. In the embodiment, the water retention depth is set to 40-50 cm.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as limiting the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (10)

1. A plain river network slope bank pollution interception system, characterized in that it includes a multi-level strip-shaped ecological interception unit parallel to the river bank line, and the ecological interception unit is provided with a filler layer along the river bank slope from bottom to top. , planting soil layer and plants planted on the planting soil layer, there are water collection pipes and water distribution pipes laid inside the filling layer, a plurality of the ecological interception units are separated by retaining walls, and the water collection pipe of the upper level ecological interception unit It communicates with the water distribution pipe of the next-level ecological interception unit through the outlet vertical pipe and the connecting pipe; wherein the connecting pipe passes through the retaining wall. 2. A plain river network slope bank pollution interception system according to claim 1, characterized in that the ecological interception unit levels are adjusted according to the slope bank width, preferably 1-5 levels. 3. A plain river network slope bank pollution interception system according to claim 1, characterized in that the water distribution pipe is used to arrange the water collected by the water collection pipe of the upper-level ecological interception unit in the next-level ecological interception unit. The packing layer of the interception unit. 4. A plain river network slope bank pollution interception system according to claim 1, characterized in that the water collecting pipes and water distribution pipes of the ecological interception unit at the same level are placed on different sides of the filling layer; the water collecting pipes and water distribution pipes of two adjacent levels are placed on different sides of the filling layer. Water pipes are placed on the same side of the fill layer. 5. A plain river network slope bank pollution interception system according to claim 1, characterized in that the water distribution flow flows horizontally and horizontally along the interception unit. 6. A plain river network slope bank pollution interception system according to claim 1, characterized in that the plain river network slope bank pollution interception system includes a water inlet, and the water inlet is connected to the first-level ecological interception unit. The water distributor is connected. 7. A plain river network slope bank pollution interception system according to claim 1, characterized in that the vertical depth of the ecological interception unit is 70-100cm; the outlet vertical pipe is higher than the bottom of the ecological interception unit. , forming a stagnant water area, and regulating the depth of the stagnant water layer to 40%-70% of the depth of the interception unit. 8. A plain river network slope bank pollution interception system according to claim 1, characterized in that the filler of the filler layer is selected from one or more of zeolite, ceramsite, pyrite, and biochar. 9. A plain river network slope bank pollution interception system according to any one of claims 1 to 8, characterized in that the depth of the planting soil layer is 10-30cm, and the third ecological interception unit First-level planting of drought-tolerant shrubs, such as one or more of oleander, hibiscus, acacia, Chinese tallow tree, pyracantha, winter jasmine, ligustrum, and nandina; subsequent ecological interception units are planted with drought-tolerant and water-emergent plants. Plants, such as one or more of arundo, canna, acanthus, windmill, and iris. 10. Application of the plain river network slope bank pollution interception system described in claim 9 in the environmental field.