Purification system and method for polder farmland and agricultural wet compound non-point source pollution and resource utilization process

Abstract

The invention provides a polder farmland and agricultural wet compound non-point source pollution purification system and method and a resource utilization process, which are applied to polder farmland areas. Comprising a root hole wetland unit, a plant polder ridge unit, a natural ecological ditch, an ecological gravel purification unit and a wetland pond unit, farmland recession water containing agricultural non-point source pollution sequentially flows through the root hole wetland unit, the plant polder ridge unit, the natural ecological ditch and the ecological gravel purification unit from a farmland to be collected into the wetland pond unit, and ecological purification treatment of the agricultural non-point source pollution is completed. By constructing a multi-stage ecological system comprising a root hole wetland unit, a plant polder ridge unit, a natural ecological ditch, an ecological gravel purification unit and a wetland pond unit, on the basis of the characteristics of centralization of polder farmland areas and developed water systems, farmland and wetland composite ecological management of water bodies is realized under the existing land conditions, and the ecological environment of the water bodies is improved. The problems that in the polder farmland area agricultural one-way ecological management process, the management effect is not ideal or the investment is high, systematic regulation and control are lacked, and the occupied area is wide are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of ecological purification of farmland non-point source pollution, and in particular to a system and method for purifying farmland wetland composite non-point source pollution and a resource utilization process. Background Art

[0002] The weifan area is characterized by low-lying terrain, developed water systems, and concentrated farmland. In the process of large-scale agricultural planting in the weifan area, the farmland runoff generated forms relatively obvious non-point source pollution. Rural non-point source pollution refers to dissolved or solid pollutants in rural life and agricultural production activities, such as soil particles, nitrogen, phosphorus, pesticide heavy metals, rural poultry and livestock manure and domestic garbage and other organic or inorganic substances. From non-specific regions, under the action of precipitation and runoff, through farmland surface runoff, farmland drainage and underground seepage, a large number of pollutants enter the receiving water bodies (rivers, lakes, reservoirs, bays). Agricultural non-point source pollution can easily cause eutrophication of river water bodies, massive reproduction of algae, reduction of aquatic biodiversity, destruction of water ecological balance, and may even cause red tides, algal blooms and other phenomena, affecting water safety. In the process of agricultural non-point source pollution control, a relatively mature 4R technology has been formed, namely source reduction, process blocking, nutrient reuse and ecological restoration. In the process of ecological governance, ecological purification technology can effectively play a certain role in the control of non-point source pollution caused by farmland drainage.

[0003] Under the traditional agricultural production and land use methods, agriculture in the Weifan area faces many ecological and environmental problems, such as serious non-point source pollution of farmland, degradation of ecological functions, and low efficiency of water resource utilization. These problems not only affect the local agricultural production and ecological environment quality, but also restrict the sustainable development of the regional economy. In the actual use process, some single ecological governance has unsatisfactory results or high investment, lack of systematic regulation, large land area, and difficult maintenance, which are important factors restricting its technological development. At the same time, in the actual application of ecological technology, the resource utilization rate of plant stems and water bodies is low, or the resource technology is difficult to implement due to the single land use and technology. Agricultural non-point source pollution in the Weifan area urgently needs to be controlled through a low-cost, in-situ multi-level, easy-to-maintain, and high-resource technology system, which can effectively improve its ecological governance efficiency. Summary of the invention

[0004] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide a system, method and resource utilization process for purifying water quality of agricultural non-point source pollution in wetland areas, while constructing a recycling system for water and plant resources.

[0005] To achieve the above-mentioned purpose and other related purposes, the present invention provides a polder-farm wetland composite non-point source pollution purification system, which is applied to the polder-farm area; comprising:

[0006] A root hole wetland unit, wherein aquatic plants and wet plants capable of forming natural root holes are planted on the root hole wetland unit, and the root hole wetland unit reduces organic matter and suspended solids in farmland runoff water through capture, root hole area filtration, plant absorption, matrix interception, and microbial degradation;

[0007] A plant embankment unit, on which aquatic plants are planted, and the plant embankment unit intercepts and slowly releases organic matter in the farmland drainage water through the root system of the aquatic plants;

[0008] Ecological gravel purification unit, used to purify organic matter, nitrogen and phosphorus pollutants in farmland runoff;

[0009] A wetland pond unit, wherein emergent plants and submerged plants are planted in the wetland pond unit to purify organic matter in the farmland drainage water, and the wetland pond unit is used for static sedimentation of the farmland drainage water;

[0010] A natural ecological ditch is also arranged between the plant embankment unit and the ecological gravel purification unit; farmland drainage containing agricultural non-point source pollution flows from the farmland through the root hole wetland unit, the plant embankment unit, the natural ecological ditch, the ecological gravel purification unit in sequence and is collected in the wetland pond unit, thus completing the ecological purification treatment of agricultural non-point source pollution.

[0011] Preferably, the natural ecological ditch is constructed based on an irrigation ditch or a drainage ditch; aquatic plants are also planted in the natural ecological ditch to purify water quality and reduce the content of nitrogen and phosphorus pollutants in farmland runoff water.

[0012] Preferably, plant stems are buried in the matrix of the rhizopore wetland unit, and aquatic plants and wetland plants are planted in the matrix; the plant stems in the matrix decay to form artificial root holes, simulating the reed root hole system of natural wetlands, which is used to purify farmland drainage containing agricultural non-point source pollution.

[0013] Preferably, the root hole wetland unit is arranged between the farmland and the plant embankment unit, and planting piles are arranged on the side of the root hole wetland unit close to the farmland, and the planting piles are used to distinguish the farmland planting area and the ecological purification area.

[0014] Preferably, the water head difference on both sides of the root hole wetland unit is 2cm-6cm.

[0015] Preferably, the ecological gravel purification unit is buried beneath the ground, and includes an inlet area, a gravel area, an outlet area, and a water collection area. The inlet area is connected to the natural ecological ditch through a gravity flow pipe; the water collection area is connected to the wetland pond unit; the farmland drainage water in the natural ecological ditch flows into the inlet area through the gravity flow pipe, flows into the outlet area after being filtered and purified in the gravel area, and then flows into the wetland pond unit after being collected in the water collection area.

[0016] Preferably, the height of the gravel area is 0.6m-1.0m; the particle size of the gravel in the gravel area is 10mm-30mm.

[0017] Preferably, the wetland pond unit may also be equipped with fish and benthic animals to form an ecosystem in the wetland pond unit.

[0018] To achieve the above purpose or other purposes, the present invention also discloses a method for purifying composite non-point source pollution of wetlands and agricultural wetlands, using the above-mentioned composite non-point source pollution purification system of wetlands and agricultural wetlands, and the steps are as follows:

[0019] S1: Plan and construct root hole wetland units, plant embankment units, natural ecological ditches, ecological gravel purification units, and wetland pond units on the periphery of farmland;

[0020] S2: After farmland irrigation or rainfall, a water head difference is formed between the farmland and the root hole wetland unit. The farmland drainage containing agricultural non-point source pollution flows from the farmland through the root hole wetland unit, plant embankment unit, natural ecological ditch, and ecological gravel purification unit in sequence and is collected in the wetland pond unit, completing the ecological purification treatment of agricultural non-point source pollution.

[0021] To achieve the above purpose or other purposes, the present invention also discloses a resource utilization process in the purification of composite non-point source pollution of embankment fields, agricultural wetlands, and the composite non-point source pollution purification system of embankment fields, wherein plant stems are buried in the matrix of the root hole wetland unit, and the sources of the plant stems include aquatic plants planted on the root hole wetland unit, aquatic plants planted on the plant embankment unit, and aquatic plants planted in the wetland pond unit;

[0022] The wetland pond unit has a water storage function and can collect farmland runoff and rainwater; the farmland runoff and rainwater can be used for irrigation of farmland crops after being purified by the wetland pond unit.

[0023] As described above, the system, method and resource utilization process for purifying compound non-point source pollution of wetlands and agricultural wetlands according to the present invention have the following beneficial effects:

[0024] 1. The present invention constructs a multi-level ecological system of root hole wetland units, plant embankment units, natural ecological ditches, ecological gravel purification units, and wetland pond units. Based on the characteristics of concentrated embankment areas and developed water systems, the present invention realizes the composite ecological management of farmland wetlands in water bodies with existing land conditions, thereby solving the problems of unsatisfactory management effects or high investment, lack of systematic regulation, large land area, and difficult maintenance in the process of one-way agricultural ecological management in embankment areas.

[0025] 2. The matrix of the root hole wetland unit in the present invention can be the stems of aquatic plants planted in the plant embankment unit and the stems of aquatic plants planted in the wetland pond unit, realizing the resource utilization of plant stems. At the same time, the wetland pond unit also has a water storage function and can collect farmland runoff and rainwater; farmland runoff and rainwater can be used for farmland crop irrigation after being purified by the wetland pond unit, realizing the resource utilization of water resources, achieving zero pollution discharge and highly cyclic utilization of resources. Its initial construction and later maintenance costs are low, and it has strong scalability.

[0026] 3. The present invention is mainly based on the existing terrain and natural conditions, and constructs complex ecological technical measures to control agricultural non-point source pollution in the embankment area, improve the resource utilization of plant stems and water bodies, does not require large-scale additional land, has low maintenance costs, and the water flow relies on gravity without power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention provides an overall schematic diagram of the dike farm wetland composite non-point source pollution purification system.

[0028] Figure 2 It is a schematic diagram of the root hole wetland unit, plant embankment unit and natural ecological ditch in the present invention;

[0029] Figure 3 It is a schematic diagram of an ecological gravel purification unit of the embankment farm wetland composite non-point source pollution purification system according to the present invention;

[0030] Figure 4 The present invention is a schematic diagram of a wetland pond unit of a composite non-point source pollution purification system for wetlands and farmlands.

[0031] Description of reference numerals:

[0032] 1. Root hole wetland unit; 2. Plant dike unit; 3. Natural ecological ditch; 4. Ecological gravel purification unit; 401. Water inlet area; 402. Gravel area; 403. Water outlet area; 404. Catchment area; 5. Wetland pond unit; 501. Emergent plants; 502. Submerged plants; 6. Planting piles; 7. Farmland. DETAILED DESCRIPTION

[0033] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0034] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0035] like Figure 1-Figure 4 As shown, the present invention provides a purifying system for composite non-point source pollution of wetland and agricultural wetlands, which is applied to wetland areas; comprising:

[0036] Root hole wetland unit 1, on which aquatic plants and wet plants that can form natural root holes are planted, and the root hole wetland unit 1 reduces organic matter and suspended matter in farmland drainage water through capture, root hole area filtration, plant absorption, matrix interception, and microbial degradation;

[0037] The plant embankment unit 2 is planted with aquatic plants, and the plant embankment unit 2 intercepts and slowly releases organic matter in the farmland drainage water through the root system of the aquatic plants;

[0038] Ecological gravel purification unit 4, used to purify organic matter, nitrogen and phosphorus pollutants in farmland drainage;

[0039] Wetland pond unit 5, in which emergent plants 501 and submerged plants 502 are planted, which are used to purify organic matter in farmland drainage water, and at the same time, wetland pond unit 5 is used for static sedimentation of farmland drainage water;

[0040] A natural ecological ditch 3 is also arranged between the plant dike unit 2 and the ecological gravel purification unit 4; farmland drainage containing agricultural non-point source pollution flows from the farmland 7 in sequence through the root hole wetland unit 1, the plant dike unit 2, the natural ecological ditch 3, and the ecological gravel purification unit 4 and is collected in the wetland pond unit 5, completing the ecological purification treatment of agricultural non-point source pollution.

[0041] The invention relates to a polder farm wetland composite non-point source pollution purification system, which constructs a multi-level ecological system of a root hole wetland unit 1, a plant embankment unit 2, a natural ecological ditch 3, an ecological gravel purification unit 4, and a wetland pond unit 5. When farmland drainage flows in the multi-level ecological system, organic matter, nitrogen, and phosphorus pollutants contained in the farmland drainage water will be filtered, intercepted, purified, and decomposed by each unit, thereby achieving source control of agricultural non-point source pollution.

[0042] Preferably, Figure 1 , Figure 2 As shown, the natural ecological ditch 3 is constructed based on the irrigation ditch or the drainage ditch; aquatic plants are also planted in the natural ecological ditch 3 to purify the water quality and reduce the content of nitrogen and phosphorus pollutants in the farmland runoff water.

[0043] Furthermore, irrigation ditches or drainage ditches are existing facilities in the weifan farmland 7 area; the aquatic plants in the natural ecological ditch 3 have a purification effect, which can enhance water purification, save land, and give play to the ecological role of the ditch. It has low investment cost and convenient maintenance, and fully utilizes the purification effect of aquatic plants to reduce the content of pollutants such as nitrogen and phosphorus in the drainage water of farmland.

[0044] Preferably, in this embodiment, plant stems (which may be appropriately matched with crop straw) are buried in the matrix of the root hole wetland unit 1, and aquatic plants and wetland plants are planted in the matrix; the plant stems in the matrix are decayed to form artificial root holes, simulating the reed root hole system of natural wetlands, which is used to purify farmland drainage containing agricultural non-point source pollution.

[0045] The root hole wetland unit 1 is constructed by simulating the reed root hole system of the natural wetland, using plant stems as the filler / medium of the matrix, which effectively changes the macropore structure of the wetland bed. At the initial stage of the construction of the root hole wetland unit 1, plant stems are buried in the subsurface layer of the wetland soil, and aquatic plants and wetland plants that can form natural root holes are planted on them. After the plant stems rot, artificial root holes are formed in the wetland.

[0046] Preferably, Figure 2 As shown, the root hole wetland unit 1 is arranged between the farmland 7 and the plant embankment unit 2, and a planting pile 6 is arranged on the side of the root hole wetland unit 1 close to the farmland 7, and the planting pile 6 is used to distinguish the planting area and the ecological purification area of ​​the farmland 7. The water head difference on both sides of the root hole wetland unit 1 is 2cm-6cm.

[0047] Furthermore, the planting piles 6 are used to prevent the irregular growth of aquatic plants and effectively distinguish the crops in the farmland 7 from the aquatic plants. On the other hand, the planting piles 6 can also block the soil in the farmland 7, give full play to the ecological role of the ridges, and effectively prevent soil erosion in the farmland 7.

[0048] Preferably, in this embodiment, the plant embankment unit 2 is based on the natural embankment, and aquatic plants are planted to form a naturally alternating growth of aquatic plants. The aquatic plants can be harvested and piled up as fillers according to the needs of the matrix of the root hole wetland unit 1. At the same time, the root system of the aquatic plants in the plant embankment unit 2 can further enhance the slow release and interception of farmland drainage, and at the same time solidify the plant embankment unit 2.

[0049] Preferably, Figure 1 , Figure 4 As shown, the ecological gravel purification unit 4 is buried under the ground, and the ecological gravel purification unit 4 includes an inlet area 401, a gravel area 402, an outlet area 403, and a water collection area 404. The inlet area 401 is connected to the natural ecological ditch 3 through a gravity flow pipeline; the water collection area 404 is connected to the wetland pond unit 5; the farmland drainage in the natural ecological ditch 3 flows into the inlet area 401 through the gravity flow pipeline, flows into the outlet area 403 after being filtered and purified in the gravel area 402, and then flows into the wetland pond unit 5 after being collected in the water collection area 404. Further, the height of the gravel area 402 is 0.6m-1.0m; the particle size of the gravel in the gravel area 402 is 10mm-30mm.

[0050] In this embodiment, the ecological gravel purification unit 4 is set up in the existing geographical location such as the shoulder of the road, the drainage outlet, etc., and the underground type is mainly composed of gravel filling. The purification unit saves the floor space and can greatly improve the cold resistance. The ecological gravel purification unit 4 has high impact load resistance, strong ability to purify organic matter, nitrogen, phosphorus and other pollutants in the water body, and lower cost than the same type of technology. The ecological gravel purification unit 4 realizes the characteristics of "zero footprint", high purification function, and the ground part restores the original land use.

[0051] Preferably, Figure 1 , Figure 4 As shown, in this embodiment, the wetland pond unit 5 can also be configured with fish and benthic animals to form an ecosystem in the wetland pond unit 5. The wetland pond unit 5 can be constructed based on the transformation of existing ponds, pools, river and lake boundary wetlands, etc., and planted with emergent plants 501 (such as reeds, cattails, etc.) and submerged plants 502 (such as Vallisneria) and other aquatic plants with purification effects, and further remove suspended matter, nitrogen, phosphorus and other pollutants in the water body through sedimentation, deep purification and other methods. In addition, the wetland pond unit 5 can be set to a plurality of units according to actual conditions, and adjacent wetland pond units 5 can be connected in parallel or in series, so there is no need to build a large area of ​​new wetland pond units 5, saving land area.

[0052] In this embodiment, relying on the multi-stage ecological purification system, land is saved and the non-point source pollution of the embankment farmland is controlled. The wetland pond unit 5 can be used for farmland flood prevention and rainwater storage in the rainy season, and can also be used for interception and purification of the backwater after irrigation in dry days, which can largely realize the water storage, water purification, soil conservation, carbon fixation and other capabilities in the system, and promote ecological balance development. The root hole wetland unit 1 and the plant embankment unit 2 can enhance the water retention capacity of the farmland wetland system in the embankment area, and at the same time purify the water body, reduce the turbidity of the backwater of the farmland, and reduce the degree of soil erosion in the farmland. At the same time, the aquatic plants on the plant embankment unit 2 and the aquatic plants in the wetland pond unit 5 can effectively purify farmland pollution, and the harvested stems can be used as fillers / mediums for pre-ecological technology to realize resource utilization in the aquatic plant system. The backwater and rainwater collected in the wetland pond unit 5 can be used for farmland reuse irrigation after purification, improve the efficiency of water resource utilization, and achieve near-zero emissions in the local ecosystem.

[0053] To achieve the above purpose or other purposes, the present invention also discloses a method for purifying composite non-point source pollution of wetlands and agricultural wetlands, using the above-mentioned composite non-point source pollution purification system of wetlands and agricultural wetlands, and the steps are as follows:

[0054] A1: A root hole wetland unit 1, a plant embankment unit 2, a natural ecological ditch 3, an ecological gravel purification unit 4, and a wetland pond unit 5 are planned to be constructed on the outer side of the farmland 7; wherein the root hole wetland unit 1 is adjacent to the farmland 7, and a planting pile 6 is also arranged between the root hole wetland unit 1 and the farmland 7;

[0055] A2: After irrigation or rainfall in farmland 7, a water head difference is formed between farmland 7 and root hole wetland unit 1. The farmland drainage containing agricultural non-point source pollution flows from farmland 7 through root hole wetland unit 1, plant embankment unit 2, natural ecological ditch 3, ecological gravel purification unit 4, and is collected in wetland pond unit 5, completing the ecological purification treatment of agricultural non-point source pollution.

[0056] Among them, farmland runoff is formed after irrigation or rainfall in the farmland, and a water head difference is formed between the planting piles 6 and the root hole wetland unit 1. On the basis of water conservation, excessive erosion of the soil is avoided to cause it to be lost. The root hole wetland unit 1 captures organic matter and suspended matter in the farmland runoff, filters it in the root hole area, absorbs it, traps it in the matrix, and degrades it with microorganisms, thereby achieving primary purification of the farmland runoff;

[0057] The farmland drainage water after primary purification flows into the plant dike unit 2, and the roots of aquatic plants planted on the plant dike unit 2 further intercept and slowly release organic matter in the farmland drainage water, thereby achieving secondary purification of the farmland drainage water;

[0058] The farmland drainage water after secondary purification flows into the natural ecological ditch 3, which collects the farmland drainage water after secondary purification. At the same time, the aquatic plants planted in the natural ecological ditch 3 further purify the organic matter in the farmland drainage water, reduce the content of nitrogen and phosphorus pollutants in the farmland drainage water, and realize the tertiary purification of the farmland drainage water;

[0059] The farmland drainage water after the third stage of purification flows into the ecological gravel purification unit 4 through the gravity flow pipe. The gravel filler filled in the ecological gravel purification unit 4 further purifies the organic matter, nitrogen, phosphorus and other pollutants in the farmland drainage water, thereby achieving the fourth stage of purification of the farmland drainage water.

[0060] The farmland drainage water after four-stage purification flows into the wetland pond unit 5, and the wetland pond unit 5 settles the farmland drainage water. At the same time, the emergent plants 501 and the submerged plants 502 in the wetland pond unit 5 further purify the farmland drainage water. The fish, benthic animals and microorganisms configured in the wetland pond unit 5 form a complete ecosystem, thereby realizing the purification of the farmland drainage water.

[0061] To achieve the above purpose or other purposes, the present invention also discloses a resource utilization process for purifying composite non-point source pollution of dikes and agricultural wetlands. The above-mentioned dikes and agricultural wetlands composite non-point source pollution purification system is adopted, and plant stems are buried in the matrix of the root hole wetland unit 1. The sources of the plant stems include aquatic plants planted on the root hole wetland unit 1, aquatic plants planted on the plant dike unit 2, and aquatic plants planted in the wetland pond unit 5; the wetland pond unit 5 has a water storage function and can collect farmland runoff and rainwater; after the farmland runoff and rainwater are purified by the wetland pond unit 5, they can be used for irrigation water in the planting area of ​​the farmland 7.

[0062] The resource utilization process in this application is mainly reflected in the following two aspects:

[0063] 1. Treatment and reuse of runoff water from farmland and rainwater from rainy days; water resource reuse mainly utilizes the water storage function of wetland pond unit 5 to collect runoff water from farmland and rainwater, which can reduce the risk of flood disasters to a certain extent. At the same time, the water body can be used for irrigation of farmland crops nearby after purification.

[0064] 2. Resource utilization of the stems of aquatic plants after harvest or part of the crop straw; among them, the stems of aquatic plants mainly come from the stems of aquatic plants after harvest from the root hole wetland unit 1, the plant dike unit 2, and the wetland pond unit 5, which can be used as the matrix filler of the root hole wetland unit 1, which can effectively improve the root hole purification effect of the root hole wetland unit 1 and realize its resource utilization. According to actual needs, it can be combined with crop straw as its filler.

[0065] The invention relates to a purifying system, method and resource utilization process for composite non-point source pollution of wetland agricultural wetlands, which are combined with multi-stage ecological purification treatment measures to save land and realize the coordinated treatment of wetland ecological control technology for non-point source pollution of wetland agricultural wetlands, thereby solving the shortcomings of unsatisfactory effect of single ecological governance or high investment, lack of systematic regulation, large land area, difficult maintenance and low resource utilization rate. At the same time, farmland drainage and aquatic plant stems after multi-stage ecological purification treatment can be fully utilized as resources, achieving zero pollution emission and highly circular resource utilization, with low initial construction and later maintenance costs, and strong scalability.

[0066] Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0067] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A polder-farm composite non-point source pollution purification system, applied to polder-farm areas; characterized in that: include: A root hole wetland unit (1), wherein aquatic plants and wet plants capable of forming natural root holes are planted on the root hole wetland unit (1), and the root hole wetland unit (1) reduces organic matter and suspended matter in farmland runoff water through capture, root hole area filtration, plant absorption, matrix interception, and microbial degradation; A plant embankment unit (2), wherein aquatic plants are planted on the plant embankment unit (2), and the plant embankment unit (2) intercepts and slowly releases organic matter in the farmland drainage water through the root system of the aquatic plants; Ecological gravel purification unit (4), used to purify organic matter, nitrogen and phosphorus pollutants in farmland drainage water; A wetland pond unit (5), wherein emergent plants (501) and submerged plants (502) are planted in the wetland pond unit (5) for purifying organic matter in farmland drainage water, and the wetland pond unit (5) is used for static sedimentation of farmland drainage water; A natural ecological ditch (3) is also arranged between the plant embankment unit (2) and the ecological gravel purification unit (4); farmland drainage containing agricultural non-point source pollution flows from the farmland (7) in sequence through the root hole wetland unit (1), the plant embankment unit (2), the natural ecological ditch (3), and the ecological gravel purification unit (4) and is collected in the wetland pond unit (5), thereby completing the ecological purification treatment of agricultural non-point source pollution.

2. The system for purifying wetland and wetland composite non-point source pollution according to claim 1 is characterized by: The natural ecological ditch (3) is constructed based on an irrigation ditch or a drainage ditch; aquatic plants are also planted in the natural ecological ditch (3) to purify water quality and reduce the content of nitrogen and phosphorus pollutants in farmland runoff water.

3. The system for purifying wetland and wetland composite non-point source pollution according to claim 1 is characterized by: The matrix of the rhizopore wetland unit (1) is buried with plant stems, and aquatic plants and wetland plants are planted in the matrix; the plant stems in the matrix decay to form artificial rhizopores, simulating the reed rhizopore system of a natural wetland, and used to purify farmland drainage containing agricultural non-point source pollution.

4. The system for purifying wetland and wetland composite non-point source pollution according to claim 3 is characterized by: The root hole wetland unit (1) is arranged between the farmland (7) and the plant embankment unit (2), and a planting pile (6) is arranged on the side of the root hole wetland unit (1) close to the farmland (7), and the planting pile (6) is used to distinguish the planting area of ​​the farmland (7) and the ecological purification area.

5. The system for purifying wetland and farmland composite non-point source pollution according to claim 4 is characterized by: The water head difference on both sides of the root hole wetland unit (1) is 2cm-6cm.

6. The system for purifying wetland and wetland composite non-point source pollution according to claim 1 is characterized by: The ecological gravel purification unit (4) is buried under the ground, and comprises an inlet area (401), a gravel area (402), an outlet area (403), and a water collection area (404). The inlet area (401) is connected to the natural ecological ditch (3) through a gravity flow pipeline; the water collection area (404) is connected to the wetland pond unit (5); The farmland drainage water in the natural ecological ditch (3) flows into the water inlet area (401) through the gravity flow pipe, flows into the water outlet area (403) after being filtered and purified in the gravel area (402), and then flows into the wetland pond unit (5) after being collected in the water collection area (404).

7. The system for purifying wetland and wetland composite non-point source pollution according to claim 6 is characterized by: The height of the gravel area (402) is 0.6m-1.0m; the particle size of the gravel in the gravel area (402) is 10mm-30mm.

8. The system for purifying wetland and wetland composite non-point source pollution according to claim 1 is characterized by: The wetland pond unit (5) may also be equipped with fish and benthic animals to form an ecosystem in the wetland pond unit (5).

9. A method for purifying composite non-point source pollution of wetlands and agricultural wetlands, using the composite non-point source pollution purification system of wetlands and agricultural wetlands as described in any one of claims 1 to 8, characterized in that: Here are the steps: S1: Plan and construct root hole wetland units (1), plant embankment units (2), natural ecological ditches (3), ecological gravel purification units (4), and wetland pond units (5) on the outer periphery of the farmland (7); S2: After irrigation or rainfall of the farmland (7), a water head difference is formed between the farmland (7) and the root hole wetland unit (1). The farmland drainage containing agricultural non-point source pollution flows from the farmland (7) through the root hole wetland unit (1), the plant embankment unit (2), the natural ecological ditch (3), and the ecological gravel purification unit (4) in sequence and is collected in the wetland pond unit (5), completing the ecological purification treatment of agricultural non-point source pollution.

10. A resource utilization process in the purification of compound non-point source pollution of wetlands and agricultural wetlands, using the compound non-point source pollution purification system of wetlands and agricultural wetlands as described in any one of claims 1 to 8, characterized in that: Plant stems are buried in the matrix of the root hole wetland unit (1), and the sources of the plant stems include aquatic plants planted on the root hole wetland unit (1), aquatic plants planted on the plant embankment unit (2), and aquatic plants planted in the wetland pond unit (5); The wetland pond unit (5) has a water storage function and can collect farmland runoff and rainwater; after being purified by the wetland pond unit (5), the farmland runoff and rainwater can be used for irrigation of crops in farmland (7).

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