A composite ecological restoration system and method for agricultural non-point source pollution of lakes

Abstract

This invention provides a composite ecological restoration system and method for agricultural non-point source pollution in lakes. The system includes several pre-treatment reservoirs located at the lake's edge, each including a sedimentation zone, a shallow water purification zone, and a deep water purification zone; several water quality improvement wetlands adjacent to the pre-treatment reservoirs; several ecological interception ditches located at the entry points of agricultural non-point source pollution into the lake; a shoreline ecological interception zone surrounding the lake and located along its shoreline; an ecological enclosure adjacent to the water quality improvement wetlands, within which a submerged plant restoration zone is arranged; several submerged plant restoration zones are located inside the ecological enclosure; and ecological floating islands are evenly distributed within the lake. This invention can effectively address the complex and variable nature of lake non-point source pollution, improve the treatment effect of lake non-point source pollution, and achieve the goal of treating different types of lakes.

Description

Technical Field

[0001] This invention relates to the field of ecological environment restoration technology, and in particular to a composite ecological restoration system and method for agricultural non-point source pollution of lakes. Background Technology

[0002] Lakes are key geographical units of the land surface system and an important component of the "mountains, rivers, forests, fields, lakes, grasslands, sand, and ice" community of life. They are irreplaceable in many aspects, including water environment security, flood control and drought relief, water purification, and biodiversity conservation. Lakes are significantly affected by global environmental change and human activities in their basins. Non-point source pollution of lakes caused by industrialization, urbanization, and intensive agriculture is a common challenge faced by countries around the world.

[0003] In recent years, with the continuous advancement of comprehensive ecological water environment management, numerous applications of ecological water environment remediation techniques have been implemented both domestically and internationally, gaining increasing recognition from managers. Commonly used methods for lake non-point source pollution remediation can be broadly categorized into physical, chemical, and biological methods. Physical methods include water diversion and replacement, dredging, and aeration; chemical methods include adding lime, using algae-killing agents, and adding iron salts for phosphorus removal; and biological methods include adding microorganisms and planting vegetation. Overall, ecological remediation technologies offer advantages such as stability, effectiveness, safety, longevity, and low operating costs.

[0004] In existing technologies, due to the uneven distribution of pollution and poor water exchange capacity of lake non-point source pollution, the restoration effect of a single ecological treatment technology is difficult to guarantee. There are few projects that utilize multiple ecological treatment technologies in synergy to address lake non-point source pollution, and a comprehensive ecological treatment technology solution with a holistic approach and good restoration results has not yet been formed. Furthermore, the applicability of engineering measures and the integrated application of different technology combinations are insufficient, leading to a lack of systematic and long-term consideration in technology application and engineering practice. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a composite ecological restoration system and method for agricultural non-point source pollution of lakes, so as to overcome the shortcomings of the prior art.

[0006] In a first aspect, the present invention provides a composite ecological restoration system for agricultural non-point source pollution in lakes, applied to lakes, the system comprising:

[0007] Several pre-treatment tanks are arranged in the edge area of ​​the lake, and the pre-treatment tanks include a sedimentation zone, a shallow water purification zone and a deep water purification zone.

[0008] Several water quality improvement wetlands are arranged adjacent to several of the aforementioned pre-treatment reservoirs;

[0009] Several ecological interception ditches are set up where agricultural non-point source pollution enters the lake;

[0010] An ecological barrier zone is set up around the lake and along the lakeshore area;

[0011] An ecological enclosure is set up adjacent to the water quality improvement wetland, and a submerged plant restoration area is arranged within the ecological enclosure.

[0012] Several submerged plant restoration zones are arranged inside the ecological enclosure;

[0013] Ecological floating islands are evenly distributed throughout the lake;

[0014] The lake is equipped with a sedimentation zone to intercept suspended particles, a shallow water purification zone to dissolve pollutants, a deep water purification zone to purify organic pollutants, a water quality enhancement wetland to improve the lake's internal hydraulic conditions, an ecological interception ditch to intercept pollutants discharged into the lake, a coastal ecological interception strip to intercept external pollution and restore the lake's shoreline, an ecological enclosure to reduce wind and waves, a submerged restoration zone to increase the stability of the lake's ecosystem and enhance its purification function, and an ecological floating island to reduce the lake's pollution load.

[0015] Compared with existing technologies, the beneficial effects of this invention are: by using a pre-treatment reservoir and water quality improvement wetlands, it can treat agricultural and domestic wastewater pollution around lakes with different centralized point discharges; by using ecological interception ditches and shoreline ecological interception belts, it can treat different linear lake non-point source pollution; and by using ecological enclosures, submerged plant restoration areas, and ecological floating islands, it can treat different non-point source pollution. Thus, it can effectively address the complex and ever-changing situation of lake non-point source pollution, improve the treatment effect of lake non-point source pollution, and achieve the purpose of treating different types of lakes.

[0016] Furthermore, emergent plants are arranged in the settlement area, including reeds, broadleaf cattails, water onions, and variegated sweet flag.

[0017] Furthermore, emergent plants are arranged in the shallow water purification zone, the water depth of the shallow water purification zone is 0.3m to 1.5m, and the bottom of the shallow water purification zone is covered with 15cm to 20cm thick porous limestone with a particle size of 5mm to 8mm.

[0018] Furthermore, the water depth of the deep water purification zone is 1.5m to 2.5m, and emergent plants and floating-leaved plants are arranged in the deep water purification zone. The emergent plants are reeds, water chestnuts, arrowhead, loosestrife, water onions, pickerelweed, canna lilies, and lotus. The floating-leaved plants are water lilies, water hyacinths, water chestnuts, and water caltrops.

[0019] Furthermore, the water quality improvement wetland is provided with a planting area, in which emergent plants, floating-leaved plants and submerged plants of different heights are arranged. A permeable enclosure is set outside the planting area, and the permeable enclosure is made of fishing net.

[0020] Furthermore, the ecological interception ditch has a trapezoidal cross-section, and planting platforms are provided on both sides of the top of the ecological interception ditch. The height of the planting platforms is 0.5m to 1m, and the water-facing side of the planting platforms is protected by ecological bags with a thickness of 0.15m.

[0021] Furthermore, the slope ratio of the two sides of the ecological interception ditch is 1:2 to 3, and aquatic plants are planted on both sides.

[0022] Furthermore, the coastal ecological interception zone is composed of emergent plants and wetland herbaceous plants, the ecological floating island is composed of double-layer fishing nets and wide floating platforms, and the submerged plant restoration area is composed of evergreen dwarf submerged plants and pollution-resistant pioneer species.

[0023] Furthermore, the ecological enclosure is made of PVC coated fabric.

[0024] Secondly, the present invention also provides a composite ecological restoration method for agricultural non-point source pollution of lakes, applied to the aforementioned composite ecological restoration system for agricultural non-point source pollution of lakes, the method comprising:

[0025] Several pre-treatment reservoirs are constructed within the lake. Within each pre-treatment reservoir, a sedimentation zone, a shallow water purification zone, and a deep water purification zone are constructed. Adjacent to the pre-treatment reservoirs, water quality improvement wetlands are constructed through landscape integration, so that the sedimentation zone, shallow water purification zone, deep water purification zone, and water quality improvement wetlands included in the pre-treatment reservoirs form a point-type pollution source ecological restoration.

[0026] Construct an ecological interception ditch at the agricultural non-point source pollution inlet of the lake;

[0027] By planting emergent plants and wetland herbaceous plants on the lake, the emergent plants and wetland herbaceous plants form an ecological interception zone along the shore, and the ecological interception zone is set up in the shore area of ​​the lake. The ecological interception ditch and the ecological interception zone along the shore form a linear pollution source ecological restoration.

[0028] An ecological enclosure is formed in the lake by arranging PVC coated fabric and planting several different kinds of plants in the lake to form a submerged plant restoration area in the lake, wherein the submerged plant restoration area is built on the inner side of the ecological enclosure.

[0029] Ecological floating islands are constructed in the lake using soilless cultivation and aquatic plants as the main components. The ecological enclosure, the submerged plant restoration area, and the ecological floating islands form a surface-type pollution source ecological restoration. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the composite ecological restoration system for agricultural non-point source pollution of lakes according to the first embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of the pre-reservoir in the first embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the water quality improvement wetland in the first embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the ecological enclosure structure in the first embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the submerged plant restoration area in the first embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the structure of the ecological floating island in the first embodiment of the present invention;

[0036] Figure 7 for Figure 6 Cross-sectional view at point AA.

[0037] Explanation of key component symbols:

[0038] 10. Pre-treatment tank; 11. Settling zone; 12. Shallow water purification zone; 13. Deep water purification zone;

[0039] 20. Wetland for water quality improvement; 21. Planting area; 22. Permeable enclosure;

[0040] 30. Ecological interception ditch; 31. Planting platform;

[0041] 40. Coastal ecological interception zone;

[0042] 50. Ecological enclosure;

[0043] 60. Submerged plant restoration area;

[0044] 70. Ecological floating islands;

[0045] 80. Lakes.

[0046] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0047] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0048] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0050] Example 1

[0051] Please see Figures 1 to 7 The figure shows a composite ecological restoration system for non-point source pollution of lake 80 in the first embodiment of the present invention. The system includes a pre-reservoir 10, a water quality improvement wetland 20, an ecological interception ditch 30, a coastal ecological interception strip 40, an ecological enclosure 50, a submerged plant restoration area 60, and an ecological floating island 70.

[0052] Several pre-treatment reservoirs 10 are provided and arranged along the edge of the lake 80. Each pre-treatment reservoir 10 includes a sedimentation zone 11, a shallow water purification zone 12, and a deep water purification zone 13. Several water quality improvement wetlands 20 are provided and arranged adjacent to the pre-treatment reservoirs 10. Several ecological interception ditches 30 are provided and located at the points where agricultural non-point source pollution enters the lake 80. A shoreline ecological interception strip 40 is set around the lake 80 and located along its shoreline. An ecological enclosure 50 is arranged adjacent to the water quality improvement wetlands 20. Several submerged plant restoration zones 60 are arranged within the ecological enclosure 50 and located on the inner side of the ecological enclosure 50. Ecological floating islands 70 are evenly distributed within the lake 80. The settling zone 11 intercepts suspended particles within the lake 80; the shallow water purification zone 12 dissolves pollutants within the lake 80; the deep water purification zone 13 purifies organic pollutants within the lake 80; the water quality enhancement wetland 20 improves the internal hydraulic conditions of the lake 80; the ecological interception ditch 30 intercepts pollutants discharged into the lake 80; the coastal ecological interception strip 40 intercepts external pollution and restores the shoreline of the lake 80; the ecological enclosure 50 reduces wind and waves in the lake 80; the submerged restoration zone 60 increases the stability of the lake 80's ecosystem and enhances its purification function; and the ecological floating islands 70 reduce the pollution load on the lake 80.

[0053] In this embodiment, a composite ecological restoration method for agricultural non-point source pollution in lakes is also proposed, which includes steps S1 to S5:

[0054] S1. Construct several pre-treatment reservoirs in the lake, and construct sedimentation zones, shallow water purification zones, and deep water purification zones within the pre-treatment reservoirs. Consider landscape design and construct water quality improvement wetlands adjacent to the pre-treatment reservoirs, so that the sedimentation zones, shallow water purification zones, deep water purification zones, and water quality improvement wetlands included in the pre-treatment reservoirs form point-type pollution source ecological restoration.

[0055] S2, construct an ecological interception ditch at the agricultural non-point source pollution inlet of the lake;

[0056] S3, by planting emergent plants and wetland herbaceous plants on the lake, the emergent plants and wetland herbaceous plants form a shoreline ecological interception zone, and the ecological interception zone is set in the shoreline area of ​​the lake, and a linear pollution source ecological restoration is formed through the ecological interception ditch and the shoreline ecological interception zone;

[0057] S4, by arranging PVC coated fabric in the lake to form an ecological enclosure, and planting several different kinds of plants in the lake, a submerged plant restoration area is formed in the lake, wherein the submerged plant restoration area is constructed on the inner side of the ecological enclosure;

[0058] S5, using soilless cultivation and aquatic plants as the main components to construct ecological floating islands in the lake, wherein the ecological enclosure, the submerged plant restoration area, and the ecological floating islands form a surface-type pollution source ecological restoration.

[0059] It should be noted that point-type remediation is formed by setting up a pre-treatment reservoir 10 and a water quality improvement wetland 20, and suspended particles in the lake 80 are intercepted by the sedimentation zone 11, the shallow water purification zone 12 can dissolve pollutants in the lake 80, and the deep water purification zone 13 can purify organic pollutants in the lake 80.

[0060] It is worth noting that the construction of the settling zone 11 utilizes the existing lake 80 morphology to create a habitat by planting emergent plants with well-developed root systems. The root adsorption of the emergent plants and the gravity settling effect are used to intercept suspended particles in the lake 80. In this embodiment, emergent plants are arranged in the settling zone 11, and the emergent plants in the settling zone 11 are reeds and water chestnuts.

[0061] It is worth noting that emergent plants are arranged in the shallow water purification zone 12, including reeds, broadleaf cattails, water onions, and variegated sweet flag. The water depth in the shallow water purification zone 12 is 0.3m, and a 15cm thick layer of porous limestone with a particle size of 5mm is laid. In practice, pollutants are efficiently degraded through various purification processes, such as filtration and sedimentation, adsorption, biodegradation by microorganisms, nitrification and denitrification, and plant absorption.

[0062] It is worth noting that the deep water purification zone 13 has a water depth of 1.5m and is equipped with emergent plants and floating-leaved plants. In this embodiment, the emergent plants are reeds, water chestnuts, arrowhead, loosestrife, water onions, pickerelweed, canna lilies, and lotus. The floating-leaved plants are water lilies, water hyacinths, water chestnuts, and water caltrops, which can purify nitrogen, phosphorus, and organic pollutants in lake 80.

[0063] It is worth noting that the water quality improvement wetland 20 is landscaped and planted with emergent plants, floating-leaved plants and submerged plants of different heights in the planting area 21. In this embodiment, the floating-leaved plants are water lilies, water chestnuts and gorgon fruit, the emergent plants are reeds and water bamboo, and the submerged plants are goldfish algae. Furthermore, a permeable enclosure 22 made of fishing net is set outside the planting area 21, which can reduce the adverse effects of large engineering areas on the growth of submerged plants.

[0064] It should be noted that the ecological interception ditch 30 and the shoreline ecological interception belt 40 can form a linear restoration of lake 80. In specific implementation, the ecological interception ditch 30 is selected according to local conditions, and the slope and bottom of the ditch are modified. Water-retaining embankments and ecological permeable dams are set up. Aquatic plants are planted on the bottom and slope of the ditch to intercept pollutants that are discharged linearly into the main body of lake 80. The shoreline ecological interception belt 40 is selected in a suitable water area along the shore of lake 80. Emergent plants and wetland herbaceous plants are planted to form a linear ecological interception belt that intercepts rainwater erosion, blocks external pollution, and has a landscape function. At the same time, the bare slopes and banks in the restoration area that are lacking vegetation are revegetated.

[0065] It is worth noting that the ecological interception ditch 30 has a trapezoidal cross-section. Planting platforms 31 are provided on both sides of the top of the ecological interception ditch 30. The height of each planting platform 31 is 0.5m. The water-facing side of the planting platform 31 is protected by ecological bag slope protection, with a thickness of 0.15m. In specific implementation, the ecological interception ditch 30 adopts a trapezoidal cross-section, with 0.5m high aquatic plant planting platforms 31 on both banks. The water-facing side of the platform is protected by ecological bag slope protection (each layer 0.15m thick), backfilled with earth, and emergent plants are planted on the top of the platform. This cross-section is suitable for existing ditches with relatively steep slopes on both banks. In other optional embodiments, the ecological interception ditch 30 adopts a trapezoidal cross-section, with a slope ratio of 1:2 on both banks, and aquatic plants are planted along the entire cross-section of the ditch. This cross-section is suitable for existing ditches with relatively gentle slopes on both banks.

[0066] It should be noted that the ecological enclosure 50, the submerged plant restoration zone 60, and the ecological floating island 70 can achieve surface restoration of lake 80. In specific implementation, surface pollution source ecological restoration includes habitat improvement, ecological enclosure 50, submerged plant restoration zone 60, aquatic animal control, and ecological floating island 70. The habitat improvement construction creates a favorable environment for underwater forest construction through water purification, fish control, and increased water transparency. The ecological enclosure arrangement uses PVC-coated fabric to control the water flow in lake 80 in a deflected manner, fully utilizing the area's clean water volume, reducing the disturbance of submerged plants by wind and waves, and improving plant survival rates. The submerged plant restoration zone 60 is constructed to purify the water... The lake is designed primarily as an underwater landscape, incorporating submerged plant species that grow in different seasons and at different water depths to increase biological stability and enhance purification capabilities, achieving a year-round evergreen effect. Aquatic animal control involves artificially releasing aquatic animals to improve the food chain and food web structure of the artificial ecosystem, stabilizing ecosystem balance and achieving aquatic biodiversity. The construction of the ecological floating islands (70) utilizes aquatic plants as the main body, applying soilless cultivation techniques and interspecies symbiosis to fully utilize water space and nutrient niches, creating a "floating water purification habitat platform" within the lake (80). This reduces pollution load in the water, significantly improves water transparency, and is positioned as close as possible to the inner side of the ecological enclosure.

[0067] It is worth noting that the water body cleanup for habitat improvement employs a combination of harvesters and manual labor to remove decaying plants, weeds, and other solid waste from the lake area. After preliminary drying and dehydration, the waste is bagged and transported off-site. Fish control in habitat improvement includes initial artificial intervention and subsequent community regulation. Fish removal utilizes physical methods such as gillnets and trawls, focusing on eliminating herbivorous and benthic omnivorous fish. Improving water transparency in habitat improvement involves adding a new, highly efficient, and non-toxic modified diatomaceous earth at a ratio of 50-150 g / m² to 21 areas within the submerged plant planting zone. 2 The solution is applied 2-3 times before and after treatment, which simultaneously destabilizes both positively and negatively charged colloidal particles, thereby greatly improving the water treatment effect. The submerged plant restoration area 60 mainly consists of evergreen dwarf submerged plants, supplemented by pollution-tolerant pioneer species. The plant community is required to have strong pollution tolerance, fast growth, strong reproductive capacity, and good ecological benefits.

[0068] In addition, through automatic water quality monitoring stations, aquatic biological community optimization, and daily inspections; the establishment of automatic water quality monitoring stations allows for scientific monitoring of various water indicators in the early stages of ecosystem construction. Data analysis helps identify problems in the system construction in a timely manner, enabling prompt countermeasures. Aquatic biological community optimization involves monitoring the growth status, diversity ratio, distribution range, biomass, and dominant species of aquatic plants in each zone, and developing control plans based on data analysis, including harvesting, thinning, replanting, and transplanting, to maintain the balance of aquatic plant species in the system. Daily inspections involve regular patrols of the lake to understand the project's progress, periodically summarizing the phased achievements, and compiling inspection records. Emergency protection measures for sudden water quality changes can also be developed to prevent damage to the lake ecosystem from various emergencies, minimizing environmental risks. By specifically addressing various point, linear, and non-point source pollution situations in lakes, this invention is long-term effective, suitable for widespread application, environmentally friendly, clean, and safe.

[0069] It is worth noting that the water quality automatic monitoring station is a micro-station, and the monitoring indicators are chemical oxygen demand, ammonia nitrogen, total nitrogen, and total phosphorus. It is powered by solar energy. Routine inspections include using a Sesquimet disc to measure water transparency, inspecting the growth of aquatic plants, observing the number and types of aquatic animals in the water, responding promptly to alien species and taking appropriate measures, including observing aquatic plants and animals for any abnormalities. If any abnormalities are found, photos are taken and recorded, and emergency measures are taken in a timely manner.

[0070] To maintain emergency response plans, in the event of a sudden large-volume influx of wastewater into the lake, the first step is to investigate the source of the wastewater, collect and analyze data on the composition, concentration, and quantity of pollutants, and then propose corresponding solutions. If the influx exceeds the ecosystem's capacity to absorb the wastewater, timely measures should be taken to reduce turbidity.

[0071] To maintain the emergency plan, when an oil film appears on the water surface, the formation of the oil film is blocked at the source, the range of oil film formation is controlled, and the further spread of the oil film is prevented from affecting submerged plants and fish. Oil film and surface floating object collectors are used to collect small floating objects such as oil and willow catkins, thereby reducing the release of pollution from floating objects and improving the water surface's appearance.

[0072] Example 2

[0073] The difference between Embodiment 2 and Embodiment 1 of the present invention is that:

[0074] The emergent vegetation used in the settlement zone 11 is mainly reeds, with a plant height of 80-120cm and a planting density of 36 plants / m². 2 The planting area accounts for 12.19% of the area of ​​subsidence zone 11; broadleaf cattails, with a plant height of 60-100cm, are planted at a density of 25 plants / m². 2 The planting area accounts for 8.01% of the area of ​​subsidence zone 11; variegated sweet flag, with a plant height of 60-100cm, is planted at a density of 25 plants / m². 2 The planting area accounts for 11.20% of the area of ​​subsidence zone 11;

[0075] The shallow water purification zone 12 has a water depth of 1.5m. The emergent plants used in the shallow water purification zone 12 are water onions, with a plant height of 80-120cm and a planting density of 36 plants / m². 2 The planting area accounts for 94.55% of the area of ​​the shallow water purification zone 12;

[0076] The emergent plants used in the deep-water purification zone 13 are reeds, with a plant height of 80-120cm and a planting density of 36 plants / m². 2 The planting area accounts for 2.68% of the area of ​​the deep water purification zone 13; water chestnuts, with a plant height of 80-120cm, are planted at a density of 16 plants / m². 2 The planting area accounts for 16.28% of the area of ​​the deep water purification zone 13; the floating-leaved plant used in the deep water purification zone 13 is water lily, with a planting density of 2 plants / m². 2 The planting area is 3.55% of the area of ​​the deep water purification zone 13; the planting density of water chestnut is 4 plants / m². 2 The planting area accounts for 8.45% of the area of ​​the deep water purification zone 13; for water chestnut, the planting density is 1 plant / 5m². 2 The planting area accounts for 10.59% of the total area of ​​the deep water purification zone 13.

[0077] Example 3

[0078] The difference between Embodiment 3 of the present invention and the embodiments described above is that:

[0079] The emergent vegetation used in the settlement zone 11 is mainly reeds, with a plant height of 80-120cm and a planting density of 36 plants / m². 2 The planting area accounts for 21.32% of the area of ​​subsidence zone 11;

[0080] The emergent plants used in the shallow water purification zone 12 are water onions, with a plant height of 80-120cm and a planting density of 36 plants / m². 2 The planting area accounts for 26.49% of the area of ​​the shallow water purification zone 12;

[0081] The emergent plants used in the deep-water purification zone 13 are reeds, with a plant height of 80-120cm and a planting density of 36 plants / m². 2 The planting area accounts for 19.76% of the area of ​​the deep water purification zone 13; water chestnuts, with a plant height of 80-120cm, are planted at a density of 16 plants / m². 2 The planting area accounts for 14.26% of the area of ​​the deep water purification zone 13; arrowhead, with a plant height of 60-100cm, is planted at a density of 16 plants / m². 2 The planting area is 10.37% of the area of ​​the deep water purification zone 13; the floating-leaved plants used in the deep water purification zone 13 are water chestnuts, with a planting density of 4 plants / m². 2 The planting area accounts for 13.09% of the area of ​​the deep water purification zone; for water chestnut, the planting density is 1 plant / 5m². 2 The planting area accounts for 8.23% of the total area of ​​the deep water purification zone.

[0082] Example 4

[0083] The difference between Embodiment 4 of the present invention and the embodiments described above is that:

[0084] The emergent plants used in the settlement zone 11 are mainly water onions, with a plant height of 80-120cm and a planting density of 36 plants / m². 2 The planting area accounts for 28.00% of the area of ​​subsidence zone 11; broadleaf cattails, with a plant height of 60-100cm, are planted at a density of 25 plants / m². 2 The planting area accounts for 7.44% of the subsidence area 11; variegated sweet flag, with a plant height of 60-100cm, is planted at a density of 25 plants / m². 2 The planting area accounts for 6.39% of the total area of ​​subsidence zone 11;

[0085] The emergent plants used in the shallow water purification zone 12 are broadleaf cattails, with a plant height of 60-100cm and a planting density of 25 plants / m². 2 The planting area accounts for 32.14% of the subsidence area 11; pickerelweed, with a plant height of 30-60cm, is planted at a density of 16 plants / m².2 The planting area accounts for 19.11% of the area of ​​subsidence zone 11; the plant height of Thalia dealbata is 30-60cm, and the planting density is 25 plants / m². 2 The planting area accounts for 14.29% of the area of ​​subsidence zone 11; loosestrife, with a plant height of 30-60cm, is planted at a density of 16 plants / m². 2 The planting area accounts for 10.57% of the area of ​​subsidence zone 11; aquatic canna lilies, with a plant height of 30-60cm, are planted at a density of 16 plants / m². 2 The planting area accounts for 8.30% of the area of ​​subsidence zone 11;

[0086] The emergent plants used in the deep-water purification zone 13 are lotus flowers, with a plant height of 80-120cm and a planting density of 1 plant / m². 2 The planting area accounts for 9.64% of the area of ​​the deep water purification zone 13; the plant height of loosestrife is 30-60cm, and the planting density is 16 plants / m². 2 The planting area accounts for 12.11% of the area of ​​the deep water purification zone 13; water onions, with a plant height of 80-120cm, are planted at a density of 36 plants / m². 2 The planting area accounts for 9.13% of the area of ​​the deep water purification zone 13; the pickerelweed plant height is 30-60cm, and the planting density is 16 plants / m². 2 The planting area accounts for 9.32% of the area of ​​the deep water purification zone 13; the plant height of Thalia dealbata is 30-60cm, and the planting density is 25 plants / m². 2 The planting area accounts for 11.63% of the area of ​​the deep water purification zone 13; the floating-leaved plant used in the construction of the deep water purification zone 13 is water lily, with a planting density of 16 plants / m². 2 The planting area accounts for 6.65% of the area of ​​the deep water purification zone 13; the planting density of *Gynostemma pentaphyllum* is 16 plants / m². 2 The planting area accounts for 6.65% of the area of ​​the deep water purification zone 13; water hyacinth is planted at a density of 16 plants / m². 2 The planting area accounts for 13.04% of the total area of ​​the deep water purification zone.

[0087] The construction of the water quality improvement wetland 20 involves planting emergent plants, floating-leaved plants, and submerged plants of different heights through landscape design to improve the hydraulic conditions inside the wetland.

[0088] Example 5

[0089] The difference between Embodiment 5 of the present invention and the embodiments described above is that:

[0090] The emergent plants used in the construction of the water quality improvement wetland 20 are lotus flowers, with a plant height of 80-120cm and a planting density of 1 plant / m². 2, the planting area is 10.34% of the wetland area; for reed, the plant height is 80 - 120 cm and the planting density is 36 plants / m 2 , the planting area is 4.86% of the wetland area; for softstem bulrush, the plant height is 80 - 120 cm and the planting density is 36 plants / m 2 , the planting area is 2.37% of the wetland area; for broadleaf cattail, the plant height is 60 - 100 cm and the planting density is 25 plants / m 2 , the planting area is 1.39% of the wetland area; for aquatic canna, the plant height is 30 - 60 cm and the planting density is 16 plants / m 2 , the planting area is 0.89% of the wetland area; for loosestrife, the plant height is 30 - 60 cm and the planting density is 16 plants / m 2 , the planting area is 1.03% of the wetland area; for yellow flag iris, the plant height is 30 - 60 cm and the planting density is 25 plants / m 2 , the planting area is 1.89% of the wetland area; for the floating-leaved plants in the construction of the water quality improvement wetland 20, yellow floating heart is adopted, and the planting density is 16 plants / m 2 , the planting area is 4.52% of the wetland area; for floatingheart, the planting density is 25 plants / m s 2 , the planting area is 2.5% of the wetland area; for waterlily, the planting density is 2 plants / m 2 , the planting area is 1.86% of the wetland area; for floating pennywort, the planting density is 16 plants / m 2 , the planting area is 2.5% of the wetland area.

[0091] Example Six

[0092] The difference between Example Six of the present invention and the above-mentioned examples is as follows:

[0093] For the emergent plants in the construction of the water quality improvement wetland 20, wild rice stem is adopted, the plant height is 80 - 120 cm, and the planting density is 16 plants / m 2 , the planting area is 8.95% of the wetland area; for softstem bulrush, the plant height is 80 - 120 cm and the planting density is 36 plants / m 2 , the planting area is 5.03% of the wetland area; for reed, the plant height is 80 - 120 cm and the planting density is 36 plants / m 2 , the planting area is 12.96% of the wetland area; for variegated calamus, the plant height is 60 - 100 cm and the planting density is 25 plants / m 2 , the planting area is 3.93% of the wetland area; for arrowhead, the plant height is 60 - 100 cm and the planting density is 16 plants / m 2The planting area accounts for 9.13% of the wetland area; the broadleaf cattail has a plant height of 60-100cm and a planting density of 25 plants / m². 2 The planting area accounts for 1.49% of the wetland area; aquatic canna lilies, with a plant height of 30-60cm, are planted at a density of 16 plants / m². 2 The planting area is 0.23% of the wetland area; for Lythrum salicaria, the plant height is 30-60cm, and the planting density is 16 plants / m². 2 The planting area accounts for 1.43% of the wetland area; pickerelweed, with a plant height of 30-60cm, is planted at a density of 16 plants / m². 2 The planting area is 0.77% of the wetland area; the floating-leaved plants used in the construction of the water quality improvement wetland 20 are water chestnuts, with a planting density of 4 plants / m². 2 The planting area covers 9.00% of the wetland area; water lilies are used, with a planting density of 2 plants / m². 2 The planting area accounts for 10.21% of the wetland area; the submerged plant used in the construction of the water quality improvement wetland 20 is *Ceratophyllum demersum*, with a planting density of 100-120 plants / m². 2 The planting area is 6.95% of the wetland area; for Hydrilla verticillata, the planting density is 100-120 plants / m². 2 The planting area accounts for 3.76% of the wetland area; for *Myriophyllum spicatum*, the planting density is 100–120 plants / m². 2 The planting area accounts for 6.58% of the wetland area; for *Potamogeton crispus*, the planting density is 100–120 plants / m². 2 The planting area accounts for 6.26% of the wetland area.

[0094] Example 7

[0095] The difference between Embodiment Seven of the present invention and the embodiments described above is that:

[0096] Ecological interception ditch 30 and riparian ecological interception belt 40; the construction of the ecological interception ditch 30 involves selecting suitable ditches according to local conditions, modifying the slopes and bottoms, setting up water-retaining embankments, and planting aquatic plants on the bottom and slopes of the ditch to intercept pollutants that are discharged linearly into the main body of lake 80; the riparian ecological interception belt 40 is selected in suitable waters along the shore of lake 80, and by planting emergent plants and wetland herbaceous plants, a linear ecological interception belt is formed to intercept rainstorm erosion, block external pollution, and also has a landscape function, while restoring the exposed slopes and banks in the restoration area due to lack of vegetation;

[0097] The water-retaining sill of the ecological interception ditch 30 has an average height of 0.2m, a longitudinal top width of 0.3m, vertical sides facing and back of the water, and a C20 concrete base plate with a thickness of 0.2m and a length of 0.9m. The transverse width of the water-retaining sill is the same as that of the ditch bottom.

[0098] The ecological interception ditch 30 is constructed with the planting of aquatic plants, mainly reeds, lotus, cattails, calamus, loosestrife, and aquatic canna.

[0099] It is worth noting that the slope revegetation adopts three-dimensional reinforced geonet and high-performance ecological substrate spraying greening technology. The three-dimensional reinforced geonet is a reinforced three-dimensional geonet formed by extruding three-dimensional polypropylene material onto a machine-woven hexagonal double-twisted steel wire mesh. The high-performance ecological substrate spraying greening technology is achieved by scientifically formulating high-performance ecological substrates that improve the soil environment, provide coverage, heat preservation, water retention, and accelerate plant growth and root development. It is applied using a liquid spraying method, which can achieve rapid turf formation and long-term greening effects. The high-performance ecological substrate includes fine hot-melt wood fiber, interlocking artificial fiber, polymer and water-retaining base, microporous particles and growth promoters.

[0100] Example 8

[0101] The difference between Embodiment 8 of the present invention and the embodiments described above is that:

[0102] The ecological interception ditch 30 adopts a trapezoidal cross-section. A 1.0m high aquatic plant planting platform 31 is set on both banks of the ditch. The water-facing side of the platform is protected by ecological bag slope protection (each layer 0.15m thick), backfilled with earth, and emergent plants are planted on the top of the platform. This cross-section is suitable for existing ditches with relatively steep slopes on both banks.

[0103] Example 9

[0104] The difference between Embodiment Nine of the present invention and the embodiments described above is that:

[0105] The slope ratio of both banks is 1:3, and the entire cross-section of the ecological interception ditch is planted with aquatic plants. This embodiment is suitable for existing ditches with relatively gentle slopes on both banks.

[0106] The riparian ecological interception zone 40 adopts a natural gentle slope cross section, and emergent plants and floating-leaved plants are mainly set in the area of ​​the natural revetment of the water body.

[0107] Densely packed pine stakes, 1.6-3.6m long and no less than 0.12m in diameter, are driven into the outside of the existing retaining wall. The stakes are arranged in a continuous and dense manner. A 2.0m wide planting platform 31 is set between the pine stakes and the existing bank slope. The platform is backfilled with ecological bagged soil. Emergent plants are planted along the existing bank slope and the top of the planting platform 31.

[0108] Example 10

[0109] The difference between Embodiment 10 of the present invention and the embodiments described above is that:

[0110] The water body cleanup for habitat improvement involves a combination of harvesters and manual labor to remove water hyacinths, golden apple snails, weeds, decaying plant roots and stems, fishing nets, floating debris, large stones and other solid waste from the lake area. After initial drying and dehydration, the waste is bagged and transported out in a centralized manner.

[0111] Fish control through habitat improvement includes early-stage artificial intervention and subsequent community regulation. Fish removal utilizes physical methods such as gillnets and trawls, focusing on eliminating herbivorous and benthic omnivorous fish.

[0112] To improve water transparency through habitat improvement, a new, highly efficient, and non-toxic modified diatomaceous earth was added to the submerged plant restoration area at a ratio of 50-150 g / m². 2 It is applied 2-3 times before and after, which simultaneously destabilizes positively and negatively charged colloidal particles, thereby greatly improving the water treatment effect.

[0113] In this embodiment, the ecological enclosure 50 consists of floats, enclosure fabric, connecting buckles, counterweights, and tensile components. The floats are horizontal timber floats. The enclosure fabric is made of double-sided coated PVC reinforced plastic fabric, and its height can be selected or customized according to different water depths. The connecting buckles are set in sections of 20m each, with quick-connect ports at both ends. The counterweight is a counterweight chain, which makes the ecological soft enclosure skirt form an underwater debris-blocking concave surface in the water flow. The tensile components include pull ropes, reinforcing strips, and tensile counterweight chains at the top, middle, and bottom of the enclosure.

[0114] The submerged plant restoration area 60 mainly consists of evergreen dwarf submerged plants, supplemented by pollution-tolerant pioneer species. The plant community is required to have strong pollution tolerance, fast growth, strong reproductive capacity and good ecological benefits.

[0115] The ecological floating island 70 is arranged inside the ecological enclosure 50. The ecological floating bed is 2m wide and consists of a 1m wide double-layer fishing net and a 1m wide floating plate. The double-layer fishing net is close to the impermeable ecological enclosure 50. Every 5m on the double-layer fishing net, pink green foxtail grass and round coin grass are mixed. Aquatic canna lilies are planted in the cultivation holes on the floating plate. The double-layer fishing net is fixed by foundation piles. The lower end of the permeable enclosure 22 is fixed by counterweight gabions. The floating plate is fixed by foundation piles, which are galvanized steel pipe piles, including a main pipe and a sleeve. The main pipe has a diameter of DN32 and a pile length of 3m. The burial depth is 2m-2.5m depending on the water depth. The sleeve is T-shaped. The floating plates are connected by buckles and binding straps. The outer perimeter of the floating plate is fixed by DN63 PB hot melt pipe. Each group of floating beds is connected by a T-joint.

[0116] Example 11

[0117] The difference between Embodiment Eleven of the present invention and the above embodiments is that:

[0118] In this embodiment, the ecological enclosure 50 mainly consists of an upper floating body, a lower enclosure, and a bottom counterweight gabion. The upper layer is secured with buoys, allowing it to rise and fall with water level changes. The lower layer is made of waterproof PVC-coated fabric, and the bottom is fixed with gabions. The gabions are 100mm*100mm*100mm in size and weigh approximately 10kg. This embodiment is primarily used on the outer side of the restoration area to prevent external water from affecting the restoration effect inside the area.

[0119] Example 12

[0120] The difference between Embodiment Twelve of the present invention and the embodiments described above is that:

[0121] In this embodiment, the ecological enclosure 50 is a permeable enclosure 22, mainly composed of a lower layer of fishing net and a bottom-weighted gabion. The lower layer of fishing net is a 10mm mesh permeable material, and the bottom is fixed with gabions. This embodiment is mainly used for the inner part of the restoration area.

[0122] Example 13

[0123] The difference between Embodiment Thirteen of the present invention and the above embodiments is that:

[0124] The submerged plant restoration area 60 mainly uses *Ceratophyllum demersum*, with a plant height of 20-50cm and a planting density of 100-120 plants / m². 2 The planting area accounts for 16.69% of the submerged plant restoration area (60 square meters); *Hydrilla verticillata*, with a plant height of 20-50 cm and a planting density of 100-120 plants / m². 2 The planting area accounts for 6.83% of the submerged plant restoration area; the plant is an evergreen dwarf Vallisneria natans, with a height of 20-50cm and a planting density of 100-120 plants / m². 2 The planting area accounts for 34.38% of the 60-square-meter submerged plant restoration area; the plant height is 20-50 cm, and the planting density is 100-120 plants / m². 2 The planting area accounts for 11.38% of the 60-square-meter submerged plant restoration area; improved *Vallisneria natans* was used, with a plant height of 20-50 cm and a planting density of 100-120 plants / m². 2 The planting area accounts for 18.76% of the 60-square-meter submerged plant restoration area; the planting density of *Potamogeton crispus* is 100-120 plants / m², with a plant height of 20-50 cm. 2 The planting area accounts for 16.69% of the 60-acre submerged plant restoration area.

[0125] The aquatic animal regulation involves introducing carnivorous fish and constructing large mollusc communities. This biological manipulation aims to create a complete food chain, build a healthy aquatic ecosystem, and increase the complexity and stability of the aquatic ecosystem. The carnivorous fish primarily used are snakehead fish (Channa argus), with a stocking density of 3 fish per 1000 m³. 2 Each fish weighs 200-500g, and the stocking quantity is 17.65% of the total number of carnivorous fish; for mandarin fish, the stocking density is 4 fish / 1000m³. 2 Each fish weighs 200-500g, and the stocking quantity is 23.53% of the total number of carnivorous fish; for silver carp, the stocking density is 10 fish / 1000m³. 2 Each fish weighed 200-500g, and the stocking quantity comprised 58.82% of the total carnivorous fish population. The mollusc community primarily consisted of *Bellamya affinis*, stocked at a density of 15g / m³. 2 Each mollusk was released at a density of 10-20g, representing 50.00% of the total mollusc community; freshwater mussels were released at a density of 10g / m³. 2 Each animal weighs 50-200g, and the release quantity is 33.33% of the total mollusc community; for freshwater shrimp, the release density is 5g / m³. 2 Each animal weighs 30-50g, and the number released represents 16.67% of the total mollusc community.

[0126] In summary, the composite ecological restoration system for non-point source pollution of lakes 80 in the above embodiments of the present invention can address different types of point-type non-point source pollution through the settling zone 11, shallow water purification zone 12, deep water purification zone 13, and water quality improvement wetland 20; it can address linear non-point source pollution through the ecological interception ditch 30 and the coastal ecological interception belt 40; and it can address different types of non-point source pollution through the ecological enclosure 50, submerged plant restoration zone 60, and ecological floating island 70. Therefore, it can effectively address the complex and variable situation of non-point source pollution in lakes 80, improve the treatment effect of non-point source pollution in lakes 80, and achieve the goal of treating different types of lakes 80.

[0127] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0128] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A composite ecological restoration system for non-point source pollution of lake agriculture, applied to a lake, characterized in that, The system includes: Several pre-treatment tanks are arranged in the edge area of ​​the lake, and the pre-treatment tanks include a sedimentation zone, a shallow water purification zone and a deep water purification zone. Several water quality improvement wetlands are arranged adjacent to several of the aforementioned pre-treatment reservoirs; Several ecological interception ditches are set up where agricultural non-point source pollution enters the lake; An ecological barrier zone is set up around the lake and along the lakeshore area; An ecological enclosure is set up adjacent to the water quality improvement wetland, and a submerged plant restoration area is arranged within the ecological enclosure. Several submerged plant restoration zones are arranged inside the ecological enclosure; Ecological floating islands are evenly distributed throughout the lake; The sedimentation zone is used to intercept suspended particles in the lake; the shallow water purification zone is used to dissolve pollutants in the lake; the deep water purification zone is used to purify organic pollutants in the lake; the water quality improvement wetland is used to improve the internal hydraulic conditions of the lake; the ecological interception ditch is used to intercept pollutants discharged into the lake; the coastal ecological interception strip is used to intercept external pollution and restore the lake's shoreline; the ecological enclosure is used to reduce wind and waves in the lake; the submerged plant restoration zone is used to increase the stability of the lake's ecosystem and improve its purification function; and the ecological floating island is used to reduce the pollution load of the lake. The ecological interception ditch has a trapezoidal cross-section, and planting platforms are provided on both sides of the top of the ecological interception ditch. The height of the planting platforms is 0.5m to 1m. The water-facing side of the planting platforms is protected by ecological bags with a thickness of 0.15m. Emergent plants are planted on the top of the planting platforms.

2. The composite ecological restoration system for lake agricultural non-point source pollution according to claim 1, characterized in that, Emergent plants are arranged in the settlement area, including reeds, broadleaf cattails, water onions, and variegated sweet flag.

3. The composite ecological restoration system for lake agricultural non-point source pollution according to claim 1, characterized in that, Emergent plants are arranged in the shallow water purification area. The water depth of the shallow water purification area is 0.3m to 1.5m. The bottom of the shallow water purification area is covered with 15cm to 20cm thick porous limestone with a particle size of 5mm to 8mm.

4. The composite ecological restoration system for lake agricultural non-point source pollution according to claim 1, characterized in that, The water depth of the deep water purification zone is 1.5m to 2.5m. Emergent plants and floating-leaved plants are arranged in the deep water purification zone. The emergent plants are reeds, water chestnuts, arrowhead, loosestrife, water onions, pickerelweed, canna lilies, and lotus. The floating-leaved plants are water lilies, water hyacinths, water chestnuts, and water caltrops.

5. The composite ecological remediation system for lake agricultural non-point source pollution according to claim 1, characterized in that, The water quality improvement wetland has a planting area, in which emergent plants, floating-leaved plants and submerged plants of different heights are arranged. A permeable enclosure is set outside the planting area, and the permeable enclosure is made of fishing net.

6. The composite ecological restoration system for lake agricultural non-point source pollution according to claim 1, characterized in that, The slope ratio of the two sides of the ecological interception ditch is 1:2 to 3, and aquatic plants are planted on both sides.

7. The composite ecological restoration system for agricultural non-point source pollution of lakes according to claim 1, characterized in that, The coastal ecological interception zone consists of emergent plants and wetland herbaceous plants, the ecological floating island consists of double-layer fishing nets and wide floating platforms, and the submerged plant restoration area consists of evergreen dwarf submerged plants and pollution-resistant pioneer species.

8. The composite ecological restoration system for agricultural non-point source pollution of lakes according to claim 1, characterized in that, The ecological enclosure is made of PVC coated fabric.

9. A composite ecological restoration method for agricultural non-point source pollution of lakes, applied to the composite ecological restoration system for agricultural non-point source pollution of lakes as described in any one of claims 1 to 8, characterized in that, The method includes: Several pre-treatment reservoirs are constructed within the lake. Within each pre-treatment reservoir, a sedimentation zone, a shallow water purification zone, and a deep water purification zone are constructed. Adjacent to the pre-treatment reservoirs, water quality improvement wetlands are constructed through landscape integration, so that the sedimentation zone, shallow water purification zone, deep water purification zone, and water quality improvement wetlands included in the pre-treatment reservoirs form a point-type pollution source ecological restoration. Construct an ecological interception ditch at the agricultural non-point source pollution inlet of the lake; By planting emergent plants and wetland herbaceous plants on the lake, the emergent plants and wetland herbaceous plants form an ecological interception zone along the shore, and the ecological interception zone is set up in the shore area of ​​the lake. The ecological interception ditch and the ecological interception zone along the shore form a linear pollution source ecological restoration. An ecological enclosure is formed in the lake by arranging PVC coated fabric and planting several different kinds of plants in the lake to form a submerged plant restoration area in the lake, wherein the submerged plant restoration area is built on the inner side of the ecological enclosure. Ecological floating islands are constructed in the lake using soilless cultivation and aquatic plants as the main components. The ecological enclosure, the submerged plant restoration area, and the ecological floating islands form a surface-type pollution source ecological restoration.

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