CN101775789A - Method for river course slope protection by using composite stream constructed wetlands - Google Patents

Abstract

The present invention relates to a method for river channel slope protection using compound flow artificial wetland, comprising the following steps: (a) setting a grass planting ditch on the slope, the cross section of the grass planting ditch is V-shaped, and plants are planted in the grass planting ditch; (b) A composite flow constructed wetland is provided at the water outlet of the grass planting ditch, and there are fillers in the composite flow constructed wetland, and reeds, cattails, sedges, black triangles, rushes, and cannas are planted on the fillers , metasequoia, calamus, water onion, arrowhead mushroom, waterylon grass, lotus seed grass, cress or carex; The water flowing from the composite flow constructed wetland is discharged into the river channel. The method for slope protection of a compound flow constructed wetland river in the present invention has good stability for river slope protection, keeps little damage to the ecological environment on both sides of the river, can beautify the river bank landscape and increase biodiversity, has low cost, and has a good effect of intercepting and purifying pollution.

Description

A Method of River Course Slope Protection Using Composite Flow Constructed Wetland

technical field

The invention relates to a method for river slope protection in the technical field of environmental protection engineering, in particular to a method for using artificial wetlands to protect river slopes.

Background technique

Constructed wetland (Constructed wetland) is a sewage treatment technology developed in the 1970s. It has the characteristics of high efficiency, low cost, and simple operation and management. The earliest constructed wetland appeared in the former West Germany, and then the technology was used in the United States and Canada. And some developed countries in Europe have developed extensively and rapidly. The research and application of constructed wetlands in my country started relatively late. The principle of water quality purification in the constructed wetland ecosystem is that in an area with a certain aspect ratio and bottom slope, soil and filler are mixed to form a filler bed, and suitable local aquatic plants are planted in the filler bed, and the sewage is in the gap between the filler and the root system of the plant. Or the surface of the packing bed flows, and the sewage is purified through the synergistic effect of packing, aquatic plants and microorganisms.

The existing river slope protection technology is varied, which can be roughly divided into three types: natural slope protection, hard slope protection and ecological slope protection. The natural slope protection technology is to use the developed root system of the plant to plant the plant on the river bank. The spread of the plant root system and the branches of the nodules fix the soil between the roots, thus playing the role of reinforcement, so that it can stabilize the soil and prevent sand , Prevent soil erosion. However, this slope protection method has the disadvantage of poor stability, and the slope surface is easily scoured to form erosion ditch in areas with developed rainwater. Hard river revetment refers to a structure composed of hard stones or concrete materials that is completely isolated from the soil. kind of form. This kind of traditional hard revetment has caused great harm to the ecological environment of the river. The hard revetment has cut off the connection between the terrestrial ecosystem and the river ecosystem, destroyed the environment for the survival, habitat and reproduction of organisms, and affected the river bank landscape and biological environment. diversity. There are many methods of ecological slope protection technologies commonly used at present, such as vegetation-type ecological concrete, geotechnical material composite planting base, articulated slope protection, three-dimensional vegetation net slope protection and other technologies, which have a good effect on bank slope protection and have certain effects on bank slope landscape. However, the interception and purification effect on non-point source pollution is limited, and the cost is too high, so the popularization and use are limited.

Contents of the invention

The technical problem to be solved by the present invention is to provide a river slope protection that has good stability, maintains little damage to the ecological environment on both sides of the river, can beautify the river bank landscape and increase biodiversity, has low cost, and has a good interception and purification effect on surface pollution. A method for river slope protection in compound flow constructed wetlands.

The present invention is achieved through the following technical solutions: a method for river channel slope protection using composite flow constructed wetland, which is characterized in that it includes the following steps:

(a) A grass planting ditch is set on the slope, the cross section of the grass planting ditch is V-shaped, and plants are planted in the grass planting ditch.

(b) A composite flow artificial wetland is provided at the water outlet of the grass planting ditch, and there is a filler in the composite flow artificial wetland, and reeds, cattails, sedges, black triangles, rushes, and cannas are planted on the fillers , metasequoia, calamus, water onion, arrowhead mushroom, waterylon grass, lotus seed grass, cress or sedge.

(c) A water outlet pipe is provided on the side of the composite flow constructed wetland adjacent to the river channel, so that the water flowing out of the composite flow constructed wetland can be discharged into the river channel.

In the above method, the filler is composed of a gravel layer at the bottom, a ceramsite layer at the middle and a sand layer at the top, and reeds, cattails, sedges, black triangles, rushes, and cannas are planted on the sand layers , metasequoia, calamus, water onion, arrowhead mushroom, waterylon grass, lotus seed grass, cress or sedge.

In the above method, the composite flow constructed wetland is composed of stepped vertical flow wetland units, the vertical flow wetland unit includes a downstream wetland unit and an upstream wetland unit, the bottom of the downstream wetland unit is connected to the bottom of the upstream wetland unit The water flowing out from the water outlet of the grass planting ditch flows into the vertical flow wetland unit from the downstream wetland unit, then flows from the bottom of the downstream wetland unit into the upstream wetland unit, and finally flows from the upstream wetland unit. The upper outflow of the wetland unit enters the next said vertical flow wetland unit.

In the above method, prefabricated concrete baffles are provided on the bottom surface and surroundings of the vertical flow wetland unit, and partitions are also arranged between the downstream wetland unit and the upstream wetland unit, and the bottom surface of the vertical flow wetland unit is connected to A water flow channel is provided between the partitions so that the water flow in the downstream wetland unit can enter the upstream wetland unit from the water flow channel.

Above-mentioned method, the thickness C of described sand layer is 8 centimeters to 10 centimetres.

In the above method, the ratio of the thickness B of the ceramsite layer to the thickness A of the gravel layer is 0.4-0.8.

In the above method, the ratio of the thickness B of the ceramsite layer to the thickness A of the gravel layer is 0.6.

The present invention has the following beneficial technical effects: the advantages and effects of the present invention are that it can stabilize the bank slope of the river channel from erosion by flowing water, and at the same time concentrate the non-point source pollution at one point, and enter the river channel after concentrated treatment in the composite flow artificial wetland. Gravel, round ceramsite and other fillers, plant roots and microorganisms in the constructed wetland form a biofilm. When the rainfall runoff carries a large amount of pollutants into the river bank slope, it first flows through the ecological brick grass planting ditch, and a part of the SS (suspended solid solids) in the runoff ) is blocked and intercepted by the plants in the grass ditch. Sewage enters the composite vertical flow artificial wetland, part of the nitrogen and phosphorus in the sewage are directly absorbed by plants and microorganisms as nutrients, and part of it is removed from the sewage through nitrification, denitrification and excessive accumulation of phosphorus by microorganisms, and organic matter passes through biofilm. Daughter-in-law and assimilation and alienation can be eliminated. The filler in the composite vertical flow constructed wetland and the blocking and interception of plant roots can also remove SS in runoff. Regular replacement of the media and harvesting of the plants will maintain the high efficiency of the system for contaminant removal. In the present invention, one of reed, cattail, sedge, black triangular, rush, canna, metasequoia, calamus, water onion, arrowhead mushroom, water yam grass, lotus seed grass, water celery, and sedge is implanted in the artificial wetland. or any combination. The vertical flow artificial wetland forms a stepped green landscape.

Description of drawings

Fig. 1 is the structural representation of the grass-planting ditch and the vertical flow wetland unit in the method for river slope protection by using a compound flow constructed wetland in the present invention;

Fig. 2 is a top view structure schematic diagram of the grass-planting ditch and the vertical flow wetland unit in the method of using the composite flow constructed wetland to protect the slope of the river course shown in Fig. 1 .

1-grass ditch, 11-water outlet, 21-vertical wetland unit, 211-downstream wetland unit, 212-upstream wetland unit, 31-gravel layer, 32-ceramsite layer, 33-sandy soil layer, 4-outlet pipe , 5- concrete prefabricated baffle, 6- clapboard.

Implementation

As shown in Figures 1 to 2, the method for river slope protection using a composite flow constructed wetland in this embodiment includes the following steps: first, a grass planting ditch 1 is set on the slope, so that the cross section of the grass planting ditch 1 is V-shaped, And plants are planted in the grass planting ditch 1 . Secondly, a composite flow constructed wetland is set at the water outlet 11 of the grass planting ditch 1, and fillers are filled in the composite flow constructed wetland. The upper sand layer 33 is composed, the thickness C of the sand layer 33 is 10 cm, and the ratio of the thickness B of the ceramsite layer 32 to the thickness A of the gravel layer 31 is 0.6. Reeds, cattails, sedges, black triangles, rushes, cannas, metasequoias, calamus, water onions, arrowhead mushrooms, waterylon grass, lotus seedlings, cress and carex are planted on the sandy soil layer 33 . The composite flow constructed wetland is composed of stepped vertical flow wetland units 21, the vertical flow wetland unit 21 includes a downstream wetland unit 211 and an upstream wetland unit 212, the bottom of the downstream wetland unit 211 is connected to the upstream wetland unit The bottoms of 212 are connected to each other, and the water flowing out from the water outlet 11 of the grass planting ditch 1 flows into the vertical flow wetland unit 21 from the downstream wetland unit 211, and then flows into the upper flow wetland unit 211 from the bottom of the downstream wetland unit 211. The wetland unit 212 finally flows out from the upper part of the upflow wetland unit 212 into the next vertical flow wetland unit 21 . Concrete prefabricated baffles 5 are arranged on the bottom surface and surroundings of the vertical flow wetland unit 21, and partitions 6 are also arranged between the downstream wetland unit 211 and the upstream wetland unit 212. The vertical flow wetland unit 21 A water flow channel is provided between the bottom surface of the slab and the partition plate 6 so that the water flow in the downstream wetland unit 211 can enter the upstream wetland unit 212 from the water flow channel. Again, a water outlet pipe 4 is provided on the side of the composite flow constructed wetland adjacent to the river channel, so that the water flowing out from the composite flow constructed wetland 2 can be discharged into the river channel. The concrete prefabricated baffle 5 can be prefabricated in a factory or cast on site, as long as the bottom and surrounding areas of the vertical flow wetland unit 21 are as impermeable as possible.

When the non-point source pollution flows from both sides of the river to the river, the non-point source pollutants flow into the grass ditch, and the plants in the grass ditch will play a certain role in blocking and intercepting the SS (suspended solid) in the pollutants. Pollutants flow into the composite flow constructed wetland 2 under the action of gravity, enter each downstream wetland unit 211 from top to bottom, and then enter the upstream wetland unit 212 from bottom to top, and pass between every two adjacent wetland units. Falling water is formed between the vertical flow wetland units 21 to increase the oxygen content of pollutants. The plants planted in the vertical flow wetland unit 21 can absorb the nutrient-rich substances in the pollutants. The surface of the filler gravel and ceramsite forms a biofilm to degrade the pollutants. After multi-stage absorption, adsorption and degradation, the sewage is finally purified and passed through The drainage pipe flows into the river, thereby achieving the purpose of purifying the sewage flowing into the river.

The advantages and effects of this method of using compound flow constructed wetlands for river channel slope protection are that it can stabilize the river bank slope from flowing water erosion, and at the same time concentrate non-point source pollution at one point, and enter the river after centralized treatment by compound flow constructed wetlands. Gravel, round ceramsite and other fillers, plant roots and microorganisms in the constructed wetland form a biofilm. When the rainfall runoff carries a large amount of pollutants into the river bank slope, it first flows through the ecological brick grass planting ditch, and a part of the SS (suspended solid solids) in the runoff ) is blocked and intercepted by the plants in the grass ditch. Sewage enters the composite vertical flow artificial wetland, part of the nitrogen and phosphorus in the sewage are directly absorbed by plants and microorganisms as nutrients, and part of it is removed from the sewage through nitrification, denitrification and excessive accumulation of phosphorus by microorganisms, and organic matter passes through biofilm. Daughter-in-law and assimilation and alienation can be eliminated. The filler in the composite vertical flow constructed wetland and the blocking and interception of plant roots can also remove SS in runoff. Regular replacement of the media and harvesting of the plants will maintain the high efficiency of the system for contaminant removal. In the present invention, one of reed, cattail, sedge, black triangular, rush, canna, metasequoia, calamus, water onion, arrowhead mushroom, water yam grass, lotus seed grass, water celery, and sedge is implanted in the artificial wetland. or any combination. The vertical flow artificial wetland forms a stepped green landscape. The slope protection method of the composite flow constructed wetland river in this embodiment makes the slope protection of the river good in stability, maintains little damage to the ecological environment on both sides of the river, can beautify the river bank landscape and increase biodiversity, has low cost, and has a good interception and purification effect on surface pollution. . The removal rate of pollutants is very high, and the removal rate of TN, TP, and COD reaches more than 85%, and the Ph value of the pollutants after treatment tends to be neutral.

In some other embodiments, the thickness C of the sand layer 33 can be any value between 8 cm and 10 cm, and the ratio of the thickness B of the ceramsite layer 32 to the thickness A of the gravel layer 31 can be 0.4 Any numerical value between 0.8 can realize the purpose of the invention of the present invention, so that the removal rate of pollutants is very high, and the removal rate of TN, TP, and COD reaches more than 70%, and the Ph value of pollutants after treatment tends to be moderate. sex. Preferably, the thickness C of the sand layer 33 may be 10 cm, and the ratio of the thickness B of the ceramsite layer 32 to the thickness A of the gravel layer 31 is 0.6.

In other embodiments, according to actual needs, reeds, cattails, sedges, black triangles, rushes, cannas, metasequoia, calamus, water onions, Arrowhead mushrooms, water yam grass, lotus seed grass, cress or sedge, make the river bank landscape effect and the effect of removing pollutants the best. The plants planted on the filler can be selected according to local conditions, and are not limited to the several described in the present invention. Pollutants can also be eventually removed from the river by regular replacement of fill and harvesting of plants.

Claims (7)

1. a method of utilizing compound flow constructed wetland to carry out river course slope protection is characterized in that, comprises the steps:

(a) on domatic grass planting ditch (1) is set, the cross section of described grass planting ditch (1) is a V-type, and kind is implanted with plant in the described grass planting ditch (1);

(b) locate to be provided with compound flow constructed wetland at the delivery port (11) of described grass planting ditch (1), in the described compound flow constructed wetland filler is arranged, plant one or more that are implanted with reed, cattail, nutgrass flatsedge, rhizoma scirpi, rush, canna, metasequoia, calamus, Scirpus tabernaemontani, arrowhead, water harmony grass, alternanthera, Chinese celery or sedge on the described filler;

(c) side of closing on the river course at described compound flow constructed wetland is provided with outlet pipe (4), so that the water that flows out from described compound flow constructed wetland enters the river course.

2. method according to claim 1, it is characterized in that, described filler is made up of the layer of gravel that is positioned at the bottom (31), the haydite layer (32) and the superposed sand layer (33) that are positioned at the middle part, plants one or more of reed, cattail, nutgrass flatsedge, rhizoma scirpi, rush, canna, metasequoia, calamus, Scirpus tabernaemontani, arrowhead, water harmony grass, alternanthera, Chinese celery or sedge on the described sand layer (33).

3. method according to claim 1 and 2, it is characterized in that, described compound flow constructed wetland is made up of stepped vertical-flow wetland unit (21), described vertical-flow wetland unit (21) comprises dirty wetland unit (211) and upper reaches wetland unit (212), the bottom mutual conduction of the bottom of described dirty wetland unit (211) and described upper reaches wetland unit (212), the water that flows out from the delivery port (11) of described grass planting ditch (1) flows into described vertical-flow wetland unit (21) from described dirty wetland unit (211), bottom from described dirty wetland unit (211) flows into described upper reaches wetland unit (212) then, flows out from the top of described upper reaches wetland unit (212) at last to enter next described vertical-flow wetland unit (21).

4. method according to claim 3, it is characterized in that, around reaching, the bottom surface of described vertical-flow wetland unit (21) is provided with concrete prefabricated baffle plate (5), also be provided with dividing plate (6) between described dirty wetland unit (211) and the described upper reaches wetland unit (212), be provided with water stream channel between the bottom surface of described vertical-flow wetland unit (21) and the described dividing plate (6) so that the middle current of described dirty wetland unit (211) can enter described upper reaches wetland unit (212) from described water stream channel.

5. method according to claim 4 is characterized in that, the thickness C of described sand layer (33) is 8 centimetres to 10 centimetres.

6. method according to claim 5 is characterized in that, the ratio of the thickness A of the thickness B of described haydite layer (32) and described layer of gravel (31) is: 0.4～0.8.

7. method according to claim 6 is characterized in that, the ratio of the thickness A of the thickness B of described haydite layer (32) and described layer of gravel (31) is: 0.6.

Images