A method for ecological restoration of wave-dissipating lake and reservoir wetlands

Abstract

The present invention relates to the technical field of ecological restoration, and specifically discloses a method for wave-dissipating lake and reservoir wetland ecological restoration. The present invention establishes a low wave-dissipating dike at the bottom of the lake shore embankment slope, which mainly serves to protect the embankment and the aquatic plant planting area. And due to the rise and fall of the water level, the low wave-dissipating dike will intercept some dead branches, leaves and soil, which can serve as a new plant restoration area, and can also become a shelter and habitat for aquatic organisms; the present invention establishes an ecological restoration wetland area between the lake shore embankment slope and the low wave-dissipating dike. By planting different emergent plants and submerged plants, the wetland structure is optimized and the wetland landscape is beautified, which can play a role in publicity and education for tourists and the surrounding people; at the same time, due to the large wind and high waves in medium and large lakes and reservoirs, the newly restored embankment and the low wave-dissipating dike are both vulnerable to water wave erosion and damage, and even the newly built dike is also at risk of being washed away, which also causes the destruction of various planted aquatic plants and aquatic plants. By establishing a steel column wave-dissipating net, the wind and waves can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of ecological restoration, and particularly relates to a method for wave-dissipating lake and reservoir wetland ecological restoration. Background Art

[0002] Rivers and lakes play an irreplaceable role in the global water environment system. They are not only important for water supply, fishery farming, and water transportation, but also play a key role in aspects such as microclimate regulation and species diversity protection. The health status of rivers and lakes is closely related to human activities. However, over-exploitation of water resources, ecological damage caused by urbanization, and the discharge of a large amount of production and domestic wastewater have caused serious water pollution to the rivers flowing through cities. The input of excessive nutrients such as nitrogen and phosphorus has severely overloaded the self-purification ability of rivers and the accommodation capacity of the water environment, and some rivers have gradually evolved into slightly polluted rivers. These unpurified river waters eventually flow into lakes and reservoirs, inevitably leading to eutrophication of lake and reservoir waters, degradation of the ecosystem, and loss of biodiversity, forming a vicious cycle.

[0003] The existing restoration technologies for the water environment of rivers, lakes and reservoirs mainly include three categories: physical, chemical, and biological, and mainly include various restoration methods such as source control and pollution interception, river channel dredging, ecological bank protection, bypass wetlands, and ecological floating beds. However, most of these use a single restoration method, and a single restoration method is difficult to treat the increasingly polluted river and lake water systems.

[0004] For example, Chinese patent document CN201610226495.9 discloses a water environment restoration system for lakes and reservoirs, including an ecological floating bed floating on the water surface of the lake and reservoir, several planting beds fixed on the ecological floating bed, an adsorption net and a reaction bed fixed at the bottom of the ecological floating bed, and an algae grid and an air diffuser arranged at the bottom of the lake and reservoir; the air diffuser is connected to an air pump through a ventilation pipe; several air holes are provided on the air diffuser; at least one air bag is fixed on the algae grid, and the air bag is connected to an air supply pipe through a charging pipe, and the input end of the air supply pipe is connected to the second output end of the air pump. Although the restoration efficiency of this system has been improved, it is not easy to construct in lakes and reservoirs with large waves, and can only be implemented in local bays with small waves and shallow water in lakes and reservoirs. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a method for wave-dissipating lake and reservoir wetland ecological restoration.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A method for wave-dissipating lake and reservoir wetland ecological restoration includes the following steps:

[0008] S1. Build a wave-dissipating low embankment at the bottom of the lake shore slope;

[0009] S2. Incline and drive wooden piles into the lakeshore embankment slope, with the driving depth being 1 / 3 - 1 / 2 of the length of the wooden piles. The wooden piles are arranged along the river course direction and are located above the low wave - proof dike. The interval between adjacent two wooden piles is 2.5 - 3 m. An ecological bag is fixed on each wooden pile, and the ecological bag is located below the lake surface.

[0010] S3. A steel column wave - proof net is arranged 8 - 10 m outside the low wave - proof dike. The steel column wave - proof net includes several channel steels arranged along the river course direction. The interval between adjacent two channel steels is 2.5 - 3 m. A wave - proof net is installed on the channel steel, and floating balls are arranged on the wave - proof net.

[0011] S4. An ecological restoration wetland area is established between the lakeshore embankment slope and the low wave - proof dike, and different aquatic plants are planted.

[0012] Preferably, in step S2, the preparation method of the ecological bag is as follows:

[0013] (1) Add biochar into a sodium hydroxide solution, heat and stir for treatment, then filter, wash and dry to obtain alkali - activated biochar.

[0014] The biochar is derived from agricultural wastes. Commonly used ones such as corn straw biochar, peanut shell biochar, coconut shell biochar, rice husk biochar, etc. can all be selected.

[0015] (2) Disperse the alkali - activated biochar in deionized water, then add carboxymethyl chitosan and epichlorohydrin thereto, stir and react. After the reaction is completed, filter, wash and dry to obtain modified biochar.

[0016] (3) Immerse the modified biochar in a calcium salt solution for calcium ion chelation, then add the modified biochar chelated with calcium ions into a mixed aqueous solution of calcium nitrate and diammonium hydrogen phosphate, heat and react. After the reaction is completed, filter, wash and dry to obtain biochar - loaded hydroxyapatite.

[0017] (4) Mix the biochar - loaded hydroxyapatite and the composite microbial bacteria powder evenly to obtain a mixture, then add the mixture into a mixed aqueous solution of sodium alginate and gelatin, oscillate and mix for 24 - 48 h, and after centrifugation, washing and drying, obtain gel particles.

[0018] (5) Put the gel particles into a bag made of polypropylene, tie the bag to seal it, and thus obtain the ecological bag.

[0019] Preferably, in step (1), the temperature of the heat - stirring treatment is 40 - 60 °C, and the time of the heat - stirring treatment is 2 - 5 h.

[0020] Preferably, in step (2), the mass ratio of the alkali-activated biochar, carboxymethyl chitosan, and epichlorohydrin is 10-15:5-8:4-6.

[0021] Preferably, in step (2), the temperature of the stirring reaction is 60-80 °C, and the time of the stirring reaction is 3-5 h.

[0022] Preferably, in step (3), the concentration of the calcium salt solution is 10-15 mmol / L, the concentration of diammonium hydrogen phosphate in the mixed aqueous solution is 3-5 mmol / L, and the molar ratio of calcium nitrate to diammonium hydrogen phosphate is 1.5-2:1.

[0023] Preferably, in step (3), the temperature of the heating reaction is 70-85 °C, and the time of the heating reaction is 48-72 h.

[0024] Preferably, in step (4), the mass ratio of the biochar-supported hydroxyapatite to the composite microbial powder is 10-15:1-3, wherein the composite microbial powder is composed of Shewanella putrefaciens powder and Bacillus subtilis powder, and the mass ratio of Shewanella putrefaciens powder to Bacillus subtilis powder is 1-2:1-2. The viable count in both Shewanella putrefaciens powder and Bacillus subtilis powder is not less than 1.0×10 8 cfu / g.

[0025] Preferably, in step (4), the dosage ratio of the mixture to the mixed aqueous solution is 2-4 g:100 mL.

[0026] Preferably, in step (4), the mass fraction of sodium alginate in the mixed aqueous solution is 3-6%, and the mass fraction of gelatin is 1-2%.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] (1) The present invention builds a low anti-wave dike at the bottom of the lake shore embankment, which mainly plays a role in protecting the embankment and the aquatic plant planting area. Due to the rise and fall of the water level, the anti-wave dike will intercept some dead branches, leaves, and soil, which can serve as a new plant restoration area and can also become a shelter and habitat for aquatic organisms.

[0029] (2) The present invention builds an ecological restoration wetland area between the lake shore embankment and the anti-wave dike. By planting different emergent plants and submerged plants, the wetland structure is optimized and the wetland landscape is beautified, which can play a role in publicity and education for tourists and the surrounding people.

[0030] (3) Since the wind and waves in medium and large lakes and reservoirs are large, up to more than 2 m, the newly repaired embankment and anti-wave dike are both vulnerable to water wave erosion and damage, and even the newly built dike is also at risk of being washed away, resulting in the destruction of various aquatic plants and aquatic plants planted. By establishing a steel column anti-wave net, the wind and waves can be effectively reduced.

[0031] (4) The ecological bags self-made in the present invention are first subjected to alkali activation treatment on biochar to increase the number of active functional groups on the surface of biochar, and then carboxymethyl chitosan is grafted onto the biochar through the cross-linking action of epichlorohydrin. On the one hand, the hydrophilic property of biochar is improved, enabling it to infiltrate faster and enhancing the adsorption performance of biochar. On the other hand, the polymer network structure of carboxymethyl chitosan is conducive to the subsequent loading of hydroxyapatite. In addition, carboxymethyl chitosan can provide a carbon source for microorganisms, improving the ability of microorganisms to degrade ammonia nitrogen. A large number of hydroxyl groups and amino groups are contained in carboxymethyl chitosan. First, calcium ions are chelated, and then the chelated calcium ions are used as seeds to further grow nano-hydroxyapatite. The high specific surface area of nano-hydroxyapatite enables it to provide a large number of adsorption sites, and the removal of ammonia nitrogen in wastewater is achieved through physical adsorption. At the same time, hydroxyapatite, as an attachment medium for microorganisms, can promote the growth and metabolism of microorganisms, further promoting biological denitrification. The composite microbial agent acts together with biochar and hydroxyapatite to better remove pollutants in wastewater. Finally, sodium alginate and gelatin are used for embedding, and calcium alginate and gelatin form a cross-linked gel structure, effectively reducing the leakage of microorganisms. At the same time, calcium alginate and gelatin have good adsorption performance and can adsorb pollutants in water. Description of the Drawings

[0032] Figure 1 It is a schematic structural diagram of the wave-dissipating lake-reservoir wetland ecological restoration provided by the present invention. Detailed Embodiments

[0033] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0034] It should be noted that, unless otherwise specified, the chemical reagents involved in the present invention are all purchased through commercial channels.

[0035] A method for wave-dissipating lake-reservoir wetland ecological restoration includes the following steps:

[0036] S1. Build a wave-dissipating low dam at the bottom of the lake shore slope.

[0037] In this step, a wave-dissipating low dam is built at the bottom of the lake shore slope, and hygrophytic plants are planted on the wave-dissipating low dam to protect the shore embankment and the waterweed planting area. Due to the rise and fall of the water level, the wave-dissipating low dam will intercept some dead branches, leaves and soil, which can serve as a new plant restoration area. And due to the porous structure of the wave-dissipating low dam, it can become a shelter and habitat for aquatic organisms.

[0038] S2. Drive the wooden piles obliquely into the lakeshore embankment slope, with the driving depth being 1 / 3 - 1 / 2 of the length of the wooden pile. The wooden piles are arranged along the river course and are located above the low wave - break dike. The interval between adjacent two wooden piles is 2.5 - 3m, and an ecological bag is fixed on each wooden pile.

[0039] In this step, the driving angle of the wooden pile is 45 - 60°, the driving depth is 1 / 3 - 1 / 2 of the length of the wooden pile, the interval between adjacent two wooden piles is 2.5 - 3m, and the purpose of driving the wooden piles is to protect the low wave - break dike.

[0040] An ecological bag is fixed on each wooden pile. The size of the ecological bag is 40cm×80cm, the weight of each ecological bag is 10 - 12kg, and the ecological bag is located below the lake surface.

[0041] Among them, the preparation method of the ecological bag is as follows:

[0042] (1) Add biochar into sodium hydroxide solution, heat and stir for treatment, then filter, wash and dry to obtain alkali - activated biochar;

[0043] (2) Disperse the alkali - activated biochar in deionized water, then add carboxymethyl chitosan and epichlorohydrin to it, stir and react. After the reaction is completed, filter, wash and dry to obtain modified biochar;

[0044] (3) Immerse the modified biochar in a calcium salt solution for calcium ion chelation, then add the modified biochar chelated with calcium ions into the mixed aqueous solution of calcium nitrate and diammonium hydrogen phosphate, heat and react. After the reaction is completed, filter, wash and dry to obtain biochar - loaded hydroxyapatite;

[0045] (4) Mix the biochar - loaded hydroxyapatite and the composite microbial powder evenly to obtain a mixture, then add the mixture into the mixed aqueous solution of sodium alginate and gelatin, oscillate and mix for 24 - 48h, and after centrifugation, washing and drying, obtain gel particles;

[0046] (5) Put the gel particles into a bag made of polypropylene, tie the bag to seal, and then the ecological bag is obtained.

[0047] Specifically, in step (1), the temperature of the heat - stirring treatment is 40 - 60°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C can be selected; the time of the heat - stirring treatment is 2 - 5h, for example, 2h, 3h, 4h, 5h can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0048] Specifically, in step (2), the mass ratio of the alkali - activated biochar, carboxymethyl chitosan and epichlorohydrin is 10 - 15:5 - 8:4 - 6.

[0049] Specifically, in step (2), the temperature of the stirring reaction is 60 - 80°C, for example, 60°C, 65°C, 70°C, 75°C, 80°C can be selected; the time of the stirring reaction is 3 - 5 h, for example, 3 h, 3.5 h, 4 h, 4.5 h, 5 h can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0050] Specifically, in step (3), the dosage ratio of the modified biochar to the calcium salt solution is 1 g:5 - 15 mL, for example, 1 g:5 mL, 1 g:8 mL, 1 g:10 mL, 1 g:12 mL, 1 g:15 mL can be selected; the concentration of the calcium salt solution is 10 - 15 mmol / L, for example, 10 mmol / L, 11 mmol / L, 12 mmol / L, 13 mmol / L, 14 mmol / L, 15 mmol / L can be selected; but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0051] More specifically, the calcium salt solution is a soluble calcium salt solution, for example, calcium nitrate solution or calcium chloride solution can be selected.

[0052] Specifically, in step (3), the dosage ratio of the modified biochar chelated with calcium ions to the mixed aqueous solution is 1 g:5 - 15 mL, for example, 1 g:5 mL, 1 g:6 mL, 1 g:8 mL, 1 g:10 mL, 1 g:12 mL, 1 g:15 mL can be selected, the concentration of diammonium hydrogen phosphate in the mixed aqueous solution is 3 - 5 mmol / L, for example, 3 mmol / L, 3.5 mmol / L, 4 mmol / L, 4.5 mmol / L, 5 mmol / L can be selected; the molar ratio of calcium nitrate to diammonium hydrogen phosphate is 1.5 - 2:1, for example, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1 can be selected; but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0053] Specifically, in step (3), the temperature of the heating reaction is 70 - 85°C, for example, 70°C, 75°C, 80°C, 85°C can be selected; the time of the heating reaction is 48 - 72 h, for example, 48 h, 54 h, 60 h, 66 h, 72 h can be selected; but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0054] Specifically, in step (4), the mass ratio of biochar-supported hydroxyapatite to the composite microbial powder is 10 - 15:1 - 3. For example, it can be 10:1, 10:2, 10:3, 12:1, 12:2, 12:3, 15:1, 15:2, or 15:3. The composite microbial powder is composed of Shewanella putrefaciens powder and Bacillus subtilis powder, and the mass ratio of Shewanella putrefaciens powder to Bacillus subtilis powder is 1 - 2:1 - 2. The viable count in both Shewanella putrefaciens powder and Bacillus subtilis powder is not less than 1.0×10 8 cfu / g.

[0055] Specifically, in step (4), the dosage ratio of the mixture to the mixed aqueous solution is 2 - 4 g:100 mL. For example, it can be 2 g:100 mL, 2.5 g:100 mL, 3 g:100 mL, 3.5 g:100 mL, or 4 g:100 mL. The mass fraction of sodium alginate in the mixed aqueous solution is 3 - 6%, and the mass fraction of gelatin is 1 - 2%.

[0056] S3. A steel column wave - prevention net is arranged 8 - 10 m outside the low wave - prevention dyke. The steel column wave - prevention net includes several channel steels arranged along the river direction, and the interval between adjacent channel steels is 2.5 - 3 m. A wave - prevention net is installed on the channel steels, and floating balls are arranged on the wave - prevention net.

[0057] In this step, the selected channel steel is No. 8 channel steel with a length of 3.5 m. The channel steel is driven 1 m into the lake bottom, and the interval between adjacent channel steels is 2.5 - 3 m. A wave - prevention net is installed on the channel steels. The wave - prevention net is made of nylon net, and the bottom of the wave - prevention net is more than 50 cm away from the lake bottom, allowing fish to freely enter and exit. Floating balls are arranged on the wave - prevention net, and the floating balls float on the water surface to tow the wave - prevention net.

[0058] In this step, due to the large wind and high waves in medium - large lakes and reservoirs, which can reach more than 2 m, the newly repaired shore dikes and low wave - prevention dikes are easily damaged by water waves scouring. Even the newly built large dikes are at risk of being washed away, and at the same time, various planted waterweeds and aquatic plants are destroyed. By establishing a steel column wave - prevention net, the wind and waves can be effectively reduced.

[0059] S4. An ecological restoration wetland area is established between the lake shore slope and the low wave - prevention dyke, and different aquatic plants are planted.

[0060] In this step, native plants are preferentially selected in the plant configuration. Through long-term adaptation to the local natural environment, native plants will show convergent adaptation to environmental conditions in terms of physiology, structure, external morphology, etc. Native plants are also the species that can best adapt to the local climate conditions. Therefore, selecting native plants can fully adapt to the local environmental conditions and quickly form a community to achieve the purpose of restoration and reconstruction. Preferentially selecting native plants can also reduce the use of alien plants and lower the ecological risk of alien plant invasion. Different plants have different growth cycles. To meet the requirements of waterfowl for food and habitat, when configuring aquatic plants in the habitat, the species, quantity, feeding habits, and habitat habits of waterfowl in this area must be fully considered. The types of aquatic plants that waterfowl like to feed on and the types of emergent or hygrophytic plants that can provide safe shelter thus become the goals of restoration and reconstruction. At the same time, according to the characteristics of the zonal distribution of wetland vegetation and the adaptation characteristics of different ecological types of plants to the hydrological environment, hygrophytic plants, emergent plants, floating-leaved rooted plants, and submerged plants are configured in appropriate areas to serve the wetland ecological landscape.

[0061] The present invention will be further described below through specific embodiments.

[0062] In the following examples and comparative examples, the biochar used is corn straw biochar.

[0063] Example 1

[0064] A method for ecological restoration of a wave-dissipating lake reservoir wetland includes the following steps:

[0065] S1. Build a wave-dissipating low dike at the bottom of the lake shore slope. The width of the wave-dissipating low dike is 2 m, the height is 1.5 m, and the length is 100 m. Ceratophyllum demersum and Myriophyllum spicatum are planted on the wave-dissipating low dike. The planting density of Ceratophyllum demersum is 20 plants / m 2 , and the planting density of Myriophyllum spicatum is 20 plants / m 2 ;

[0066] S2. Drive 3-m-long wooden stakes obliquely into the lake shore slope. The angle between the wooden stakes and the horizontal plane is 45°. The driving depth of the wooden stakes is 1 m. The wooden stakes are arranged along the river direction. The interval between adjacent two wooden stakes is 3 m. The number of wooden stakes is 33. And the wooden stakes are located above the wave-dissipating low dike. An ecological bag is fixed on each wooden stake. The size of the ecological bag is 40 cm × 80 cm. The weight of each ecological bag is 10 kg. The ecological bags are located below the lake surface;

[0067] Among them, the preparation method of the ecological bag is as follows:

[0068] (1) Add 10 g of biochar to 100 mL of 1 mol / L sodium hydroxide solution, heat and stir at 60 °C for 3 h, then filter, wash, and dry to obtain alkali-activated biochar;

[0069] (2) Disperse 12 g of alkali-activated biochar in 100 mL of deionized water, then add 6 g of carboxymethyl chitosan and 5 g of epichlorohydrin thereto, stir and react at 80 °C for 3 h. After the reaction is completed, filter, wash, and dry to obtain modified biochar;

[0070] (3) Immerse 10 g of modified biochar in 100 mL of 10 mmol / L calcium nitrate solution, impregnate for 2 h for calcium ion chelation, and then add 10 g of modified biochar chelated with calcium ions to 100 mL of a mixed aqueous solution containing calcium nitrate and diammonium hydrogen phosphate. The concentration of diammonium hydrogen phosphate in the mixed aqueous solution is 4 mmol / L, and the molar ratio of calcium nitrate to diammonium hydrogen phosphate is 1.6:1. Heat and react at 75 °C for 60 h. After the reaction is completed, filter, wash, and dry to obtain biochar-supported hydroxyapatite;

[0071] (4) Mix 10 g of biochar-supported hydroxyapatite and 2 g of composite microbial powder evenly. The composite microbial powder is composed of Shewanella putrefaciens powder and Bacillus subtilis powder with a mass ratio of 1:1. The viable count of Shewanella putrefaciens powder is 1.0×10 8 cfu / g, and the viable count of Bacillus subtilis powder is 1.0×10 8 cfu / g to obtain a mixture. Then add 2 g of the mixture to 100 mL of a mixed aqueous solution of sodium alginate and gelatin. The mass fraction of sodium alginate in the mixed aqueous solution is 5%, and the mass fraction of gelatin is 1%. Oscillate and mix for 24 h, centrifuge, wash, and dry to obtain gel particles;

[0072] (5) Put the gel particles into a bag made of polypropylene with a size of 40 cm×80 cm, tie the seal to obtain an ecological bag.

[0073] S3. A steel column wave break net is arranged 10 m outside the low wave break dyke. The steel column wave break net includes channel steels arranged along the river direction, and the positions of the channel steels correspond to the wooden piles. The selected channel steel is No. 8 channel steel with a length of 3.5 m. The channel steel is driven 1 m into the lake bottom, and the interval between adjacent channel steels is 3 m. A wave break net is installed on the channel steel. The wave break net is made of nylon net. The bottom of the wave break net is 50 cm from the lake bottom, allowing fish to freely enter and exit; Floating balls are arranged on the wave break net;

[0074] S4. An ecological restoration wetland area is established between the lake shore slope and the low wave break dyke, and different aquatic plants are planted. Submerged plants and emergent plants are planted along the lake shore slope from bottom to top. The submerged plants are Vallisneria natans and Potamogeton malaianus. The planting density of Vallisneria natans is 20 plants / m 2 , and the planting density of Potamogeton malaianus is 20 plants / m 2 , and the emergent plants are Phragmites australis and Miscanthus lutarioriparius. The planting density of Phragmites australis is 15 plants / m 2, the planting density of Miscanthus lutarioriparius is 15 plants / m 2 , and at the same time, water lilies and Hydrilla verticillata are also planted between the low wave - proof dike and the steel column wave - proof net. The planting density of water lilies is 2 plants / m 2 , and the planting density of Hydrilla verticillata is 20 plants / m 2 .

[0075] Example 2

[0076] A method for ecological restoration of wave - dissipating lake - reservoir wetlands, comprising the following steps:

[0077] S1. Establish a low wave - proof dike at the bottom of the lakeshore embankment slope. The width of the low wave - proof dike is 2m, the height is 1.5m, and the length is 100m. Ceratophyllum demersum and Myriophyllum spicatum are planted on the low wave - proof dike. The planting density of Ceratophyllum demersum is 20 plants / m 2 , and the planting density of Myriophyllum spicatum is 20 plants / m 2 ;

[0078] S2. Obliquely drive 3m - long wooden stakes into the lakeshore embankment slope. The angle between the wooden stakes and the horizontal plane is 45°, the driving depth of the wooden stakes is 1m, the wooden stakes are arranged along the river direction, the interval between adjacent two wooden stakes is 3m, the number of wooden stakes is 33, and the wooden stakes are located above the low wave - proof dike. An ecological bag is fixed on each wooden stake. The size of the ecological bag is 40cm×80cm, and the weight of each ecological bag is 12kg. The ecological bags are located below the lake surface;

[0079] Among them, the preparation method of the ecological bag is as follows:

[0080] (1) Add 10g of biochar to 100mL of 1mol / L sodium hydroxide solution, heat and stir at 40°C for 5h, then filter, wash, and dry to obtain alkali - activated biochar;

[0081] (2) Disperse 10g of alkali - activated biochar in 100mL of deionized water, then add 5g of carboxymethyl chitosan and 4g of epichlorohydrin to it, stir and react at 60°C for 5h. After the reaction is completed, filter, wash, and dry to obtain modified biochar;

[0082] (3) Immerse 10g of modified biochar in 100mL of 15mmol / L calcium nitrate solution for 2h for calcium ion chelation, then add 10g of modified biochar chelated with calcium ions to 100mL of a mixed aqueous solution containing calcium nitrate and diammonium hydrogen phosphate. The concentration of diammonium hydrogen phosphate in the mixed aqueous solution is 5mmol / L, and the molar ratio of calcium nitrate to diammonium hydrogen phosphate is 1.5:1. Heat and react at 70°C for 72h. After the reaction is completed, filter, wash, and dry to obtain biochar - loaded hydroxyapatite;

[0083] (4) Mix 10 g of biochar-supported hydroxyapatite and 1 g of composite microbial powder evenly. The composite microbial powder is composed of Shewanella putrefaciens powder and Bacillus subtilis powder with a mass ratio of 1:1. The viable count of Shewanella putrefaciens powder is 1.0×10 8 cfu / g, and the viable count of Bacillus subtilis powder is 1.0×10 8 cfu / g to obtain a mixture. Then, add 4 g of the mixture to 100 mL of an aqueous solution of sodium alginate and gelatin. The mass fraction of sodium alginate in the aqueous solution is 3%, and the mass fraction of gelatin is 2%. Oscillate and mix for 24 h, and then centrifuge, wash, and dry to obtain gel particles;

[0084] (5) Put the gel particles into a bag made of polypropylene with dimensions of 40 cm×80 cm, and tie the seal to obtain an ecological bag.

[0085] S3. A steel column wave break net is arranged 10 m outside the low wave break dyke. The steel column wave break net includes channel steels arranged along the river direction, and the positions of the channel steels correspond to the wooden piles. The selected channel steel is No. 8 channel steel with a length of 3.5 m. The channel steel is driven 1 m into the lake bottom, and the interval between adjacent channel steels is 3 m. A wave break net is installed on the channel steel. The wave break net is made of nylon net. The bottom of the wave break net is 50 cm from the lake bottom, allowing fish to freely enter and exit; floating balls are arranged on the wave break net;

[0086] S4. An ecological restoration wetland area is established between the lake shore slope and the low wave break dyke, and different aquatic plants are planted. Submerged plants and emergent plants are planted from bottom to top along the lake shore slope. The submerged plants are Vallisneria natans and Potamogeton malaianus. The planting density of Vallisneria natans is 20 plants / m 2 , and the planting density of Potamogeton malaianus is 20 plants / m 2 . The emergent plants are Phragmites australis and Miscanthus lutarioriparius. The planting density of Phragmites australis is 15 plants / m 2 , and the planting density of Miscanthus lutarioriparius is 15 plants / m 2 . At the same time, Nymphaea tetragona and Hydrilla verticillata are also planted between the low wave break dyke and the steel column wave break net. The planting density of Nymphaea tetragona is 2 plants / m 2 , and the planting density of Hydrilla verticillata is 20 plants / m 2 .

[0087] Example 3

[0088] A method for wave-dissipating lake-reservoir wetland ecological restoration includes the following steps:

[0089] S1. Build a low wave break dyke at the bottom of the lake shore slope. The width of the low wave break dyke is 2 m, the height is 1.5 m, and the length is 100 m. Ceratophyllum demersum and Vallisneria natans are planted on the low wave break dyke. The planting density of Ceratophyllum demersum is 20 plants / m 2 , and the planting density of Vallisneria natans is 20 plants / m 2;

[0090] S2. Drive 3m long wooden stakes obliquely into the lakeshore embankment slope. The angle between the wooden stakes and the horizontal plane is 45°. The driving depth of the wooden stakes is 1m. The wooden stakes are arranged along the river course, and the interval between adjacent wooden stakes is 3m. The number of wooden stakes is 33. And the wooden stakes are located above the low wave - proof dike. An ecological bag is fixed on each wooden stake. The size of the ecological bag is 40cm×80cm, and the weight of each ecological bag is 10kg. The ecological bags are located below the lake surface;

[0091] Among them, the preparation method of the ecological bag is as follows:

[0092] (1) Add 10g of biochar to 100mL of 1mol / L sodium hydroxide solution, heat and stir at 60°C for 2h, then filter, wash and dry to obtain alkali - activated biochar;

[0093] (2) Disperse 15g of alkali - activated biochar in 100mL of deionized water, then add 8g of carboxymethyl chitosan and 6g of epichlorohydrin to it, stir and react at 80°C for 3h. After the reaction is completed, filter, wash and dry to obtain modified biochar;

[0094] (3) Immerse 10g of modified biochar in 100mL of 12mmol / L calcium nitrate solution for 2h for calcium ion chelation. Then add 10g of modified biochar chelated with calcium ions to 100mL of a mixed aqueous solution containing calcium nitrate and diammonium hydrogen phosphate. The concentration of diammonium hydrogen phosphate in the mixed aqueous solution is 3mmol / L, and the molar ratio of calcium nitrate to diammonium hydrogen phosphate is 2:1. Heat and react at 85°C for 48h. After the reaction is completed, filter, wash and dry to obtain biochar - loaded hydroxyapatite;

[0095] (4) Mix 10g of biochar - loaded hydroxyapatite and 3g of composite microbial powder evenly. The composite microbial powder is composed of Shewanella putrefaciens powder and Bacillus subtilis powder with a mass ratio of 2:1. The viable count of Shewanella putrefaciens powder is 1.0×10 8 cfu / g, and the viable count of Bacillus subtilis powder is 1.0×10 8 cfu / g to obtain a mixture. Then add 3g of the mixture to 100mL of a mixed aqueous solution of sodium alginate and gelatin. The mass fraction of sodium alginate in the mixed aqueous solution is 4%, and the mass fraction of gelatin is 1%. Oscillate and mix for 24h, and then centrifuge, wash and dry to obtain gel particles;

[0096] (5) Put the gel particles into a bag made of polypropylene with a size of 40cm×80cm, tie the seal, and then the ecological bag is obtained.

[0097] S3. A steel column wave - proof net is arranged 10 m away from the outside of the low wave - proof dike. The steel column wave - proof net includes channel steels arranged along the river course direction, and the positions of the channel steels correspond to those of the wooden piles. The selected channel steel is No. 8 channel steel with a length of 3.5 m. The channel steel is driven 1 m into the lake bottom, and the interval between adjacent channel steels is 3 m. A wave - proof net is installed on the channel steel. The wave - proof net is made of nylon net, and the bottom of the wave - proof net is 50 cm away from the lake bottom, allowing fish to freely enter and exit; floating balls are arranged on the wave - proof net.

[0098] S4. An ecological restoration wetland area is established between the lake - shore slope and the low wave - proof dike, and different aquatic plants are planted. Submerged plants and emergent plants are planted from bottom to top along the lake - shore slope. The submerged plants are Vallisneria natans and Potamogeton malaianus. The planting density of Vallisneria natans is 25 plants / m 2 and the planting density of Potamogeton malaianus is 25 plants / m 2 ; the emergent plants are Phragmites australis and Miscanthus lutarioriparius. The planting density of Phragmites australis is 15 plants / m 2 and the planting density of Miscanthus lutarioriparius is 15 plants / m 2 . At the same time, Nymphaea tetragona and Hydrilla verticillata var. rosburghii are also planted between the low wave - proof dike and the steel column wave - proof net. The planting density of Nymphaea tetragona is 2 plants / m 2 and the planting density of Hydrilla verticillata var. rosburghii is 20 plants / m 2 .

[0099] Comparative Example 1

[0100] A method for ecological restoration of a wave - dissipating lake - reservoir wetland includes the following steps:

[0101] S1. A low wave - proof dike is built at the bottom of the lake - shore slope. The width of the low wave - proof dike is 2 m, the height is 1.5 m, and the length is 100 m. Ceratophyllum demersum and Myriophyllum spicatum are planted on the low wave - proof dike. The planting density of Ceratophyllum demersum is 20 plants / m 2 and the planting density of Myriophyllum spicatum is 20 plants / m 2 ;

[0102] S2. 3 - m - long wooden piles are obliquely driven into the lake - shore slope. The angle between the wooden piles and the horizontal plane is 45°, the driving depth of the wooden piles is 1 m, the wooden piles are arranged along the river course direction, the interval between adjacent wooden piles is 3 m, the number of wooden piles is 33, and the wooden piles are located above the low wave - proof dike. An ecological bag is fixed on each wooden pile. The size of the ecological bag is 40 cm×80 cm, and the weight of each ecological bag is 10 kg. The ecological bags are located below the lake surface;

[0103] Among them, the preparation method of the ecological bag is as follows:

[0104] Mix 10 g of biochar and 2 g of compound microbial bacteria powder evenly. The compound microbial bacteria powder is composed of Shewanella putrefaciens powder and Bacillus subtilis powder with a mass ratio of 1:1. The viable count of Shewanella putrefaciens powder is 1.0×10 8cfu / g, the viable count of the Bacillus subtilis powder is 1.0×10 8 cfu / g to obtain a mixed material, and then 2 g of the mixed material is added to 100 mL of an aqueous mixed solution of sodium alginate and gelatin. The mass fraction of sodium alginate in the aqueous mixed solution is 5%, and the mass fraction of gelatin is 1%. After shaking and mixing for 24 h, centrifuging, washing, and drying are carried out to obtain gel particles;

[0105] The gel particles are put into a bag made of polypropylene with a size of 40 cm×80 cm, and the opening is tied to obtain an ecological bag.

[0106] S3. A steel column wave break net is arranged 10 m outside the low wave break dyke. The steel column wave break net includes channel steels arranged along the river direction. The positions of the channel steels correspond to those of the wooden piles. The selected channel steel is No. 8 channel steel with a length of 3.5 m. The channel steel is driven 1 m into the lake bottom, and the interval between adjacent channel steels is 3 m. A wave break net is installed on the channel steel. The wave break net is made of nylon net. The bottom of the wave break net is 50 cm from the lake bottom, allowing fish to freely enter and exit; floating balls are arranged on the wave break net;

[0107] S4. An ecological restoration wetland area is established between the lake bank slope and the low wave break dyke, and different aquatic plants are planted. Submerged plants and emergent plants are planted from bottom to top along the lake bank slope. The submerged plants are Vallisneria natans and Potamogeton malaianus. The planting density of Vallisneria natans is 20 plants / m 2 , and the planting density of Potamogeton malaianus is 20 plants / m 2 , and the emergent plants are Phragmites australis and Miscanthus lutarioriparius. The planting density of Phragmites australis is 15 plants / m 2 , and the planting density of Miscanthus lutarioriparius is 15 plants / m 2 , and at the same time, Nymphaea tetragona and Hydrilla verticillata are also planted between the low wave break dyke and the steel column wave break net. The planting density of Nymphaea tetragona is 2 plants / m 2 , and the planting density of Hydrilla verticillata is 20 plants / m 2 .

[0108] Compared with Example 1, in Comparative Example 1, the biochar was not modified, and the biochar was directly blended with the composite microbial powder.

[0109] The following table shows the change table of the pollutant content in the lake reservoir water before and 3 months after ecological restoration in Example 1 and Comparative Example 1:

[0110]

[0111] It can be seen from the table that the wave-dissipating lake reservoir wetland ecological restoration method provided by the present invention significantly reduces the total nitrogen, total phosphorus, and ammonia nitrogen contents in the lake reservoir water, and the ecological restoration effect is very remarkable, having good application prospects.

[0112] Finally, it should be noted that the above embodiments do not limit the present invention in any form. For those skilled in the art, based on the present invention, some modifications and improvements can be made. Therefore, any modification or improvement made without departing from the spirit of the present invention falls within the scope of protection required by the present invention.

Claims

1. A wave-breaking lake wetland ecological restoration method, characterized in that: The steps include: S1. Build a wave-breaking embankment at the bottom of the lake bank slope; S2. Drive wooden piles obliquely into the lake bank slope to a depth of 1 / 3-1 / 2 of the length of the wooden piles. The wooden piles are arranged along the river channel and located above the wave-breaking dike. The interval between two adjacent wooden piles is 2.5-3m. An eco-bag is fixed on each wooden pile, and the eco-bag is located below the lake surface. The preparation method of the eco-bag is as follows: (1) adding biochar to a sodium hydroxide solution, heating and stirring, and then filtering, washing, and drying to obtain alkali-activated biochar; (2) dispersing the alkali-activated biochar in deionized water, then adding carboxymethyl chitosan and epichlorohydrin thereto, stirring to react, and after the reaction is completed, filtering, washing, and drying to obtain modified biochar; (3) immersing the modified biochar in a calcium salt solution to chelate calcium ions, then adding the modified biochar with chelated calcium ions to a mixed aqueous solution of calcium nitrate and diammonium phosphate, heating the mixture for reaction, and after the reaction is completed, filtering, washing, and drying to obtain biochar-loaded hydroxyapatite; (4) The biochar-loaded hydroxyapatite and the composite microbial powder are mixed evenly to obtain a mixture, and then the mixture is added to a mixed aqueous solution of sodium alginate and gelatin, and the mixture is shaken and mixed for 24-48 hours, and the gel particles are obtained by centrifugation, washing, and drying; (5) putting the gel particles into a bag made of polypropylene and sealing it to obtain an eco-bag; S3, a steel column wave-breaking net is arranged 8-10m outside the wave-breaking dike, the steel column wave-breaking net comprises a number of channel steels arranged along the river channel, the interval between two adjacent channel steels is 2.5-3m, the channel steels are equipped with a wave-breaking net, and a buoy is arranged on the wave-breaking net; S4. Establish an ecological restoration wetland area between the lake bank slope and the wave-breaking dike and plant different aquatic plants.

2. The wave-breaking lake wetland ecological restoration method according to claim 1 is characterized in that: In step (1), the temperature of the heating and stirring treatment is 40-60° C., and the time of the heating and stirring treatment is 2-5 h.

3. The wave-breaking lake wetland ecological restoration method according to claim 1 is characterized in that: In step (2), the mass ratio of alkali-activated biochar, carboxymethyl chitosan and epichlorohydrin is 10-15:5-8:4-6.

4. The method for ecological restoration of lake and reservoir wetlands according to claim 1, characterized in that: In step (2), the stirring reaction temperature is 60-80° C., and the stirring reaction time is 3-5 h.

5. The wave-breaking lake wetland ecological restoration method according to claim 1 is characterized in that: In step (3), the solubility of the calcium salt solution is 10-15 mmol / L, the concentration of diammonium hydrogen phosphate in the mixed aqueous solution is 3-5 mmol / L, and the molar ratio of calcium nitrate to diammonium hydrogen phosphate is 1.5-2:

1.

6. The wave-breaking lake wetland ecological restoration method according to claim 1 is characterized in that: In step (3), the heating reaction temperature is 70-85°C and the heating reaction time is 48-72h.

7. The wave-breaking lake wetland ecological restoration method according to claim 1 is characterized in that: In step (4), the mass ratio of biochar-loaded hydroxyapatite to composite microbial powder is 10-15:1-3, wherein the composite microbial powder is composed of Shewanella putrefaciens powder and Bacillus subtilis powder, the mass ratio of Shewanella putrefaciens powder to Bacillus subtilis powder is 1-2:1-2, and the number of viable bacteria in Shewanella putrefaciens powder and Bacillus subtilis powder is not less than 1.0×10 8 cfu / g.

8. The wave-breaking lake wetland ecological restoration method according to claim 1 is characterized in that: In step (4), the ratio of the mixed material to the mixed aqueous solution is 2-4 g: 100 mL.

9. The wave-breaking lake wetland ecological restoration method according to claim 1 is characterized in that: In step (4), the mass fraction of sodium alginate in the mixed aqueous solution is 3-6%, and the mass fraction of gelatin is 1-2%.

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