Waterfront space ecological restoration system for coping with agricultural non-point source pollution

Abstract

The utility model relates to a waterfront space ecological restoration system for coping with agricultural non-point source pollution, which comprises an ecological interception ditch, an anoxic ecological ditch, an aerobic ecological ditch and a soil infiltration bed which are sequentially distributed downwards along a slope surface, water inlets and water outlets of the anoxic ecological ditch, the aerobic ecological ditch and the soil infiltration bed are respectively positioned at two end parts in respective length directions, and the ecological interception ditch, the anoxic ecological ditch, the aerobic ecological ditch and the soil infiltration bed are sequentially communicated along the water flow direction. The method has the beneficial effects that according to research, the horizontal distance between the water surface of the narrow waterfront space and a farmland or an ecological protection red line is only 2-3m, and the space capable of implementing ecological restoration is very limited, so that the water flow path is fully prolonged by utilizing the length advantage, the contact time of sewage and filler is prolonged, conditions are provided for full biochemical reaction, and the economic benefit is increased. Furthermore, the narrow waterfront space is fully utilized to intercept and reduce non-point source pollution caused by farmland irrigation and initial rainwater, so that the problem that the nitrogen and phosphorus content of an agricultural non-point source is too high is effectively solved.

Description

Technical Field

[0001] The utility model relates to the technical field of ecological restoration, in particular to an ecological restoration system for waterfront space to deal with agricultural non-point source pollution. Background Technique

[0002] The formation reasons of agricultural non-point source pollution are various and have become an important source of water environmental pollution. Among them, farmland drainage is one of the main reasons for agricultural non-point source pollution. Nitrogen and phosphorus, as essential nutrients for plant growth, are widely used in agricultural production. The nitrogen and phosphorus not absorbed by plants seep into surface water and groundwater with rainfall and irrigation, causing water pollution and eutrophication. Existing research shows that more than 50% of nitrogen and phosphorus in surface water abroad comes from farmland runoff, while 30% - 60% of agricultural non-point source nitrogen and phosphorus in China comes from farmland runoff. In recent years, in response to agricultural non-point source pollution, domestic and foreign scholars have proposed a whole-process treatment plan from source control to end treatment, such as building constructed wetlands and setting up ecological buffer zones. And relevant research has proved that the above measures can effectively reduce agricultural non-point source pollution. However, according to investigations, in many areas of our country, there are problems such as the distance between basic farmland and river water surface being too close, and the distance between the ecological protection red line and the river water surface being too close, resulting in a very limited ecological restoration space that can be utilized, making it difficult for traditional ecological restoration plans to play a role due to land area limitations. How to effectively utilize the narrow waterfront space to make it efficiently play the role of pollutant interception and reduction and effectively control non-point source pollution has become the key to breaking through the control of non-point source pollution on the narrow waterfront shoreline. Content of the Utility Model

[0003] The technical problem to be solved by the utility model is to provide an ecological restoration system for waterfront space to deal with agricultural non-point source pollution so as to overcome the deficiencies in the above-mentioned prior art.

[0004] The technical solution of the utility model to solve the above technical problem is as follows: an ecological restoration system for waterfront space to deal with agricultural non-point source pollution, including: an ecological interception ditch, an anoxic ecological ditch, an aerobic ecological ditch and a soil infiltration bed which are sequentially distributed downward along the slope in a limited waterfront slope space. The water inlets and outlets of the anoxic ecological ditch, the aerobic ecological ditch and the soil infiltration bed are respectively located at two ends of their respective length directions, and the ecological interception ditch, the anoxic ecological ditch, the aerobic ecological ditch and the soil infiltration bed are sequentially connected along the water flow direction.

[0005] The beneficial effects of the utility model are:

[0006] The ecological interception ditch is used to intercept particulate pollutants in sewage, and make heavier particulate matters such as sand, gravel and plant residues in the sewage precipitate at the bottom, while suspended particulate matters float on the upper part, so as to preliminarily reduce the sewage. The ecological interception ditch can also play the role of a regulating pond, mainly regulating the water volume to make the water volume entering the anoxic ecological ditch more uniform;

[0007] The anoxic ecological ditch is used to decompose macromolecular organic matter into small-molecular organic matter that can be utilized by microorganisms. The microorganisms then make full use of the carbon source in the sewage for denitrification, converting nitrate nitrogen into nitrogen gas, and storing energy for the full progress of phosphorus removal.

[0008] The aerobic ecological ditch conducts nitrification reactions, reduces ammonia nitrogen, further reduces organic matter. The phosphorus-accumulating bacteria utilize the stored energy to effectively remove phosphorus. And through the combination of the anoxic ecological ditch and the aerobic ecological ditch, nitrogen, phosphorus, COD, etc. can be effectively reduced.

[0009] The soil infiltration bed further reduces pollutants as a whole, and the treated water meets the standards and flows into the receiving water body.

[0010] According to the investigation, the horizontal distance between the water surface of the narrow waterfront space and the farmland or the ecological protection red line is only 2m - 3m, and the space for ecological restoration is very limited. Considering the land area limitation factor and the goal of efficiently reducing non-point source pollution, technologies such as ecological intercepting ditches, anoxic ecological ditches, aerobic ecological ditches, and soil infiltration beds are adopted. Inlets and outlets are set at both ends of the anoxic ecological ditch, aerobic ecological ditch, and soil infiltration bed in their respective length directions. By taking advantage of the length, the water flow path is fully extended, and the contact time between the sewage and the filler is increased, providing conditions for the full progress of biochemical reactions. Furthermore, the narrow waterfront space is fully utilized to intercept and reduce the non-point source pollution brought by farmland irrigation and initial rainwater, effectively solving the problem of excessive nitrogen and phosphorus in agricultural non-point sources, making the water quality of the river inlet section meet the standards, not affecting the flood discharge safety. And the near-natural design concept makes the whole system present a green, natural, and vibrant appearance, beautifying the local environment and being conducive to the realization of carbon sink value.

[0011] The whole system operates without additional power and can operate smoothly by relying on the gravity difference. It is energy-free, green, and low-carbon. The cost of the whole system is relatively low, the operation and maintenance workload is small, simple, and the cost is low. The operation and maintenance only lie in the subsequent maintenance and management of plants, which is suitable for treating the non-point source pollution problems of narrow waterfront spaces on a large scale.

[0012] Based on the above technical solutions, the present utility model can also be improved as follows.

[0013] Further, the widths of the ecological intercepting ditch, anoxic ecological ditch, aerobic ecological ditch, and soil infiltration bed are each 0.5m - 0.8m, and the lengths of the ecological intercepting ditch, anoxic ecological ditch, aerobic ecological ditch, and soil infiltration bed are each 2m - 4m.

[0014] The beneficial effects of adopting the above are as follows: It can be effectively applied to the narrow waterfront space of 2m - 3m. By taking advantage of the length, the water flow path is fully extended, and the contact time between the sewage and the filler is increased, providing conditions for the full progress of biochemical reactions.

[0015] Furthermore, an outlet is provided at the upper part of the ecological interception ditch, and amphibious plants are provided in the ecological interception ditch.

[0016] The further beneficial effects are as follows: When no sewage flows into the system, since the outlet of the ecological interception ditch is located at the upper part, there will be a certain amount of accumulated water at the lower part, which can meet the growth of amphibious plants. The planted plants not only have the functions of reducing pollutants and secreting oxygen, but also have the function of carbon fixation.

[0017] Furthermore, a plurality of first guide plates which are vertically arranged along the length direction of the first fine crushed stone filler layer in the anoxic ecological ditch and are used to extend the flow path of water are arranged.

[0018] The further beneficial effects are as follows: The sewage can fully contact with the filler, enhancing the anaerobic and anoxic biochemical reactions and improving the removal rate of pollutants.

[0019] Furthermore, a slow-release carbon source is added to the first fine crushed stone filler layer in the anoxic ecological ditch, and the slow-release carbon source is straw.

[0020] The further beneficial effects are as follows: The sewage flowing out from the ecological interception ditch first enters the anoxic ecological ditch for reaction to make full use of the organic pollutants in the non-point source pollution as a carbon source to effectively reduce nitrogen and phosphorus. In order to enhance the denitrification effect of denitrification, the slow-release carbon source added to the first fine crushed stone filler layer can continuously release carbon source into the first fine crushed stone filler layer for the use of anoxic microorganisms, thereby improving the nitrogen and phosphorus removal effect;

[0021] In addition, the slow-release carbon source is straw. On the one hand, straw can continuously release carbon source into the first fine crushed stone filler layer for the use of anoxic microorganisms, further facilitating the reduction of pollutants. On the other hand, the biological affinity of straw can provide a richer and more diverse growth and reproduction space for microorganisms. At the same time, straw can also play a heat preservation effect, enabling the anoxic ecological ditch to effectively reduce pollutants in cold weather. In addition, it realizes the resource utilization of agricultural waste, solves the problem of rural straw disposal, and increases the benefits brought thereby.

[0022] Furthermore, the anoxic ecological ditch includes: an anoxic denitrification tank. In the anoxic denitrification tank, a first fine crushed stone filler layer, a first geomembrane and a first soil planting layer are sequentially laid from bottom to top. First drought-tolerant emergent plants are planted on the first soil planting layer. Inlets and outlets are respectively provided at the lower and upper parts of the first fine crushed stone filler layer at the two ends of the anoxic denitrification tank in its length direction;

[0023] A first water distribution tank and a first water collection tank are respectively arranged at two end parts in the length direction of the anoxic denitrification tank. The water inlet of the anoxic denitrification tank is communicated with the first water distribution tank, and the water outlet of the anoxic denitrification tank is communicated with the first water collection tank. The water outlet at the upper part of the ecological interception ditch is communicated with the water inlet at the upper part of the first water distribution tank through a connecting pipe, and the water outlet at the upper part of the first water collection tank is communicated with the water inlet of the aerobic ecological ditch through a connecting pipe.

[0024] The further beneficial effects of the above are as follows: The first fine gravel packing layer uses fine gravel, which saves costs and increases the attachment area of microorganisms.

[0025] The anoxic denitrification tank adopts a water flow design with water entering from the bottom and flowing out from the top. When the inside of the anoxic denitrification tank is filled with sewage during the arrival of non-point source pollution, an anaerobic and anoxic environment is presented inside the anoxic denitrification tank, which is beneficial to the progress of anaerobic and anoxic biochemical reactions, such as denitrification and nitrogen removal, and accumulates energy for phosphorus-accumulating bacteria to reduce total phosphorus.

[0026] Further, a plurality of second guide plates arranged vertically along the length direction of the coarse gravel packing layer in the aerobic ecological ditch are arranged to extend the water flow path.

[0027] The further beneficial effects of the above are as follows: The sewage can fully contact with the packing, enhancing the aerobic biochemical reaction and improving the removal rate of pollutants.

[0028] Further, a plurality of rope-shaped artificial waterweeds are buried along the water flow direction in the coarse gravel packing layer.

[0029] The further beneficial effects of the above are as follows: On the one hand, it can promote the oxygen conduction effect, increase the dissolved oxygen in the system, and provide a more sufficient aerobic environment for the coarse gravel packing layer. On the other hand, it provides a suitable growth and reproduction space for microorganisms, that is, it is used as a biological carrier for biofilm formation, strengthens the aerobic biochemical reaction, and promotes the reduction of pollutants.

[0030] Further, the aerobic ecological ditch includes: an aerobic nitrification tank. A coarse gravel packing layer is laid in the aerobic nitrification tank. Planting pots are arranged on the coarse gravel packing layer, and second drought-tolerant emergent plants are planted in the planting pots. Inlets and outlets are respectively arranged at the upper and lower parts of the coarse gravel packing layer at two end parts in the length direction of the aerobic nitrification tank.

[0031] A second water distribution tank and a second water collection tank are respectively arranged at two end parts in the length direction of the aerobic nitrification tank. The water inlet of the aerobic nitrification tank is communicated with the second water distribution tank, and the water outlet of the aerobic nitrification tank is communicated with the second water collection tank. The water outlet of the anoxic ecological ditch is communicated with the water inlet at the upper part of the second water distribution tank through a connecting pipe, and the water outlet at the lower part of the second water collection tank is communicated with the water inlet of the soil infiltration bed through a connecting pipe.

[0032] The further beneficial effects are as follows: Coarse crushed stone is used for the coarse crushed stone filler layer, with a larger porosity, and the filler is connected to the outside atmosphere, resulting in better internal oxygen-rich conditions, providing good environmental conditions for sufficient aerobic biochemistry to promote nitrification reaction, reduce ammonia nitrogen concentration, and promote the reduction of total phosphorus by polyphosphate-accumulating organisms; the aerobic nitrification tank adopts an upward-inlet and downward-outlet water flow design to prevent water accumulation inside the aerobic nitrification tank.

[0033] Furthermore, a second fine crushed stone filler layer, a second geomembrane, and a second soil planting layer are sequentially laid from bottom to top inside the soil infiltration bed. Amphibious herbaceous plants are planted on the second soil planting layer. Water inlets and outlets are respectively arranged at the lower and upper parts of the second fine crushed stone filler layer at both ends of the soil infiltration bed in its length direction.

[0034] The further beneficial effects are as follows: The sewage flowing out of the aerobic ecological ditch enters from the lower part of the second fine crushed stone filler layer and flows out from the upper part of the second fine crushed stone filler layer, presenting a plug flow form as a whole, further reducing pollutants, and the effluent flows into the receiving water body. Description of the Drawings

[0035] Figure 1 It is a side view of the waterfront space ecological restoration system for dealing with agricultural non-point source pollution in the present invention;

[0036] Figure 2 It is a structural diagram of the waterfront space ecological restoration system for dealing with agricultural non-point source pollution in the present invention.

[0037] In the drawings, the list of components represented by each reference numeral is as follows:

[0038] 1. Ecological interception ditch, 110. Amphibious plants, 2. Anoxic ecological ditch, 210. Anoxic denitrification tank, 211. First fine crushed stone filler layer, 212. First geomembrane, 213. First soil planting layer, 214. First drought-tolerant emergent plant, 215. First guide plate, 216. Slow-release carbon source, 220. First water distribution tank, 230. First collection tank, 3. Aerobic ecological ditch, 310. Aerobic nitrification tank, 311. Coarse crushed stone filler layer, 312. Second guide plate, 313. Rope-shaped artificial aquatic plants, 320. Planting pot, 321. Second drought-tolerant emergent plant, 330. Second water distribution tank, 340. Second collection tank, 4. Soil infiltration bed, 410. Second fine crushed stone filler layer, 420. Second geomembrane, 430. Second soil planting layer, 440. Amphibious herbaceous plants, 5. Connecting pipe. Detailed Embodiments

[0039] The principles and features of the present invention are described below with reference to the drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0040] Example 1

[0041] As Figure 1 、 Figure 2 shown, a waterfront space ecological restoration system for dealing with agricultural non-point source pollution includes: an ecological interception ditch 1, an anoxic ecological ditch 2, an aerobic ecological ditch 3, and a soil infiltration bed 4 that are sequentially distributed downward along the slope in a limited waterfront slope space;

[0042] The water inlet and outlet of the anoxic ecological ditch 2 are respectively located at two ends in its length direction, the water inlet and outlet of the aerobic ecological ditch 3 are respectively located at two ends in its length direction, and the water inlet and outlet of the soil infiltration bed 4 are respectively located at two ends in its length direction;

[0043] The ecological interception ditch 1, the anoxic ecological ditch 2, the aerobic ecological ditch 3, and the soil infiltration bed 4 are sequentially connected along the water flow direction;

[0044] The ecological interception ditch 1 is used to intercept particulate pollutants in sewage, and let heavier particulate matters such as sand, gravel, and plant residues in the sewage precipitate at the bottom, while suspended particulate matters float on the upper part, so as to preliminarily reduce the sewage. The ecological interception ditch 1 also functions as a regulating tank, mainly regulating the water volume to make the water volume entering the anoxic ecological ditch 2 more uniform;

[0045] The anoxic ecological ditch 2 is used to decompose macromolecular organic matters into small molecular organic matters that can be utilized by microorganisms. The microorganisms then make full use of the carbon source in the sewage for denitrification, converting nitrate nitrogen into nitrogen gas, and storing energy for the full progress of phosphorus removal;

[0046] The aerobic ecological ditch 3 conducts nitrification reaction to reduce ammonia nitrogen and further reduce organic matters. Polyphosphate-accumulating bacteria use the stored energy to effectively remove phosphorus. And through the combination of the anoxic ecological ditch 2 and the aerobic ecological ditch 3, nitrogen, phosphorus, COD, etc. can be effectively reduced;

[0047] The soil infiltration bed 4 further reduces pollutants as a whole, and the treated water meets the standards and flows into the receiving water body;

[0048] According to the investigation, the horizontal distance between the water surface of the narrow waterfront space and the farmland or the ecological protection red line is only 2m - 3m, and the space available for ecological restoration is very limited. Therefore, water inlets and outlets are set at two ends in the length direction of the anoxic ecological ditch 2, the aerobic ecological ditch 3, and the soil infiltration bed 4 respectively, making full use of the advantage in length to fully extend the water flow path, increasing the contact time between the sewage and the filler, providing conditions for the full progress of biochemical reactions, and then making full use of the narrow waterfront space for ecological restoration to effectively solve the problem of excessive agricultural non-point source nitrogen and phosphorus;

[0049] In addition, non-point source pollution does not occur all the time, and the entire system does not always treat sewage. When farmland drainage or initial rainwater flows into the system, pollutants are reduced according to the aforementioned treatment, that is, the physical and biological processes such as plant absorption, microbial reduction, and filler adsorption are fully utilized to reduce non-point source pollution, which has good practical value and can play a role for a long time.

[0050] Example 2

[0051] As Figure 1 shown, this example is a further improvement based on Example 1, specifically as follows:

[0052] The widths of the ecological interception ditch 1, anoxic ecological ditch 2, aerobic ecological ditch 3, and soil infiltration bed 4 are each 0.5 m to 0.8 m, and the lengths of the ecological interception ditch 1, anoxic ecological ditch 2, aerobic ecological ditch 3, and soil infiltration bed 4 are each 2 m to 4 m, which can be effectively applied to narrow waterfront spaces of 2 m to 3 m. The advantage in length is utilized to fully extend the water flow path, increase the contact time between sewage and the filler, and provide conditions for the full progress of biochemical reactions.

[0053] Example 3

[0054] As Figure 2 shown, this example is a further improvement based on Example 1 or 2, specifically as follows:

[0055] The upper part of the ecological interception ditch 1 is provided with a water outlet. There are amphibious plants 110 in the ecological interception ditch 1, which can initially reduce the pollutants entering its interior. In addition, a grid filter is arranged at the water outlet of the ecological interception ditch 1 to prevent suspended particulate matter from entering the anoxic ecological ditch 2 and blocking the internal matrix of the anoxic ecological ditch 2. When no sewage flows into the system, since the water outlet of the ecological interception ditch 1 is located in the upper part, there will be a certain amount of accumulated water in the lower part, which can meet the growth of the amphibious plants 110. The planted plants not only have the functions of reducing pollutants and secreting oxygen, but also have the function of carbon fixation.

[0056] Example 4

[0057] As Figure 2 shown, this example is a further improvement based on any one of Examples 1 to 3, specifically as follows:

[0058] A plurality of first guide plates 215 arranged vertically along the length direction are arranged in the first fine gravel filler layer 211 of the anoxic ecological ditch 2 to extend the water flow path, so that the sewage can fully contact the filler, enhance the anaerobic and anoxic biochemical reactions, and improve the removal rate of pollutants.

[0059] Example 5

[0060] As Figure 2 shown, this embodiment is a further improvement based on any one of Embodiments 1 to 4, and the specific content is as follows:

[0061] A slow-release carbon source 216 is added to the first fine gravel packing layer 211 of the anoxic ecological ditch 2. The sewage flowing out of the ecological interception ditch 1 first enters the anoxic ecological ditch 2 for reaction, so as to make full use of the organic pollutants in the non-point source pollution as a carbon source to effectively reduce nitrogen and phosphorus. In order to enhance the denitrification effect of denitrification, the slow-release carbon source 216 added to the first fine gravel packing layer 211 can continuously release carbon sources into the first fine gravel packing layer 211 for anoxic microorganisms to use, thereby improving the nitrogen and phosphorus removal effect;

[0062] In addition, the slow-release carbon source 216 is preferably straw. On the one hand, straw can continuously release carbon sources into the first fine gravel packing layer 211 for anoxic microorganisms to use, which is further conducive to the reduction of pollutants. On the other hand, the biological affinity of straw can provide a richer and more diverse growth and reproduction space for microorganisms. At the same time, straw can also play a heat preservation effect, so that the anoxic ecological ditch 2 can effectively reduce pollutants even in cold weather. In addition, it realizes the resource utilization of agricultural waste, solves the problem of rural straw disposal, and increases the benefits brought thereby.

[0063] Embodiment 6

[0064] As Figure 2 shown, this embodiment is a further improvement based on Embodiment 5, and the specific content is as follows:

[0065] The anoxic ecological ditch 2 includes: an anoxic denitrification tank 210. In the anoxic denitrification tank 210, a first fine gravel packing layer 211, a first geomembrane 212, and a first soil planting layer 213 are laid in sequence from bottom to top. The packing uses fine gravel, which saves costs and increases the attachment area of microorganisms;

[0066] A first drought-tolerant emergent plant 214 is planted on the first soil planting layer 213. The drought-tolerant emergent plant is a drought-tolerant aquatic plant, and the first soil planting layer 213 has a certain water and fertilizer retention capacity, so it will not die in the short term. The planted plants not only have the functions of reducing pollutants, secreting oxygen, but also have the function of carbon fixation. Inlets and outlets are respectively provided at the lower and upper parts of the first fine gravel packing layer 211 at the two ends of the anoxic denitrification tank 210 in its length direction, that is, the anoxic denitrification tank 210 adopts a water flow design of bottom-in and top-out. When the inside of the anoxic denitrification tank 210 is filled with sewage during the non-point source pollution, the inside of the anoxic denitrification tank 210 presents an anaerobic and anoxic environment, which is conducive to the progress of anaerobic and anoxic biochemical reactions, such as denitrification and nitrogen removal, and accumulates energy for the phosphorus-accumulating bacteria to reduce the total phosphorus;

[0067] At both end portions in the length direction of the anoxic denitrification tank 210, a first water distribution tank 220 and a first water collection tank 230 are respectively arranged. The water inlet of the anoxic denitrification tank 210 is communicated with the first water distribution tank 220. The first water distribution tank 220 shares a wall with the anoxic denitrification tank 210. The sewage in the first water distribution tank 220 enters the anoxic denitrification tank 210 through the water inlet at the lower part of the anoxic denitrification tank 210. The first water distribution tank 220 can further uniformly adjust the water volume.

[0068] The water outlet of the anoxic denitrification tank 210 is communicated with the first water collection tank 230. The first water collection tank 230 shares a wall with the anoxic denitrification tank 210. The sewage that has completed the anaerobic and anoxic biochemical reactions in the anoxic denitrification tank 210 enters the first water collection tank 230 through the water outlet at the upper part of the anoxic denitrification tank 210. The water outlet at the upper part of the ecological interception ditch 1 is communicated with the water inlet at the upper part of the first water distribution tank 220 through a connecting pipe 5. The water flowing out of the ecological interception ditch 1 will enter the first water distribution tank 220. And the water outlet at the upper part of the first water collection tank 230 is communicated with the water inlet of the aerobic ecological ditch 3 through a connecting pipe 5, so that the water in the first water collection tank 230 can flow into the aerobic ecological ditch 3 through the connecting pipe 5.

[0069] Example 7

[0070] As Figure 2 shown, this example is a further improvement on any one of Examples 1 to 6, specifically as follows:

[0071] In the coarse gravel filler layer 311 of the aerobic ecological ditch 3, a plurality of second guide plates 312 arranged vertically along its length direction are arranged to extend the water flow path, so that the sewage can fully contact the filler, enhance the aerobic biochemical reaction, and improve the removal rate of pollutants.

[0072] Example 8

[0073] As Figure 2 shown, this example is a further improvement on any one of Examples 1 to 7, specifically as follows:

[0074] A plurality of rope-shaped artificial waterweeds 313 are buried along the water flow direction in the coarse gravel filler layer 311. On the one hand, it can promote the oxygen conduction effect, increase the dissolved oxygen in the system, and provide a more sufficient aerobic environment for the coarse gravel filler layer 311. On the other hand, it provides a suitable growth and reproduction space for microorganisms, that is, serves as a biological carrier for biofilm formation, strengthens the aerobic biochemical reaction, and promotes the reduction of pollutants.

[0075] Furthermore: It is preferably that rope-shaped artificial waterweeds 313 are arranged on both sides of each second guide plate 312 in the coarse gravel filler layer 311.

[0076] Example 9

[0077] As Figure 2 shown, this embodiment is a further improvement based on Embodiment 1, 7 or 8, and the specific details are as follows:

[0078] The aerobic ecological ditch 3 includes: an aerobic nitrification tank 310, in which a layer of coarse gravel filler 311 is laid. The filler is made of coarse gravel with a larger porosity and is connected to the outside atmosphere, so that the internal oxygen-rich condition is better, providing good environmental conditions for sufficient aerobic biochemical reactions to promote the nitrification reaction, reduce the ammonia nitrogen concentration, and promote the reduction of total phosphorus by polyphosphate-accumulating bacteria;

[0079] In addition, planting pots 320 are arranged on the coarse gravel filler layer 311, with gaps left between the planting pots 320. The second drought-tolerant emergent plants 321 are planted in the planting pots 320. The drought-tolerant emergent plants are drought-tolerant aquatic plants, and the planting pots 320 have a certain water and fertilizer retention capacity, so they will not die in the short term. The planted plants not only have the effects of reducing pollutants and secreting oxygen, but also have the effect of carbon fixation;

[0080] At the two ends of the aerobic nitrification tank 310 in its length direction, an inlet and an outlet are respectively provided above and below the coarse gravel filler layer 311. That is, the aerobic nitrification tank 310 adopts an upward-inlet and downward-outlet water flow design to prevent water from accumulating inside the aerobic nitrification tank 310; the second water distribution tank 330 and the second collection tank 340 are respectively arranged at the two ends of the aerobic nitrification tank 310 in its length direction;

[0081] The inlet above the aerobic nitrification tank 310 is connected to the second water distribution tank 330, and the outlet below the aerobic nitrification tank 310 is connected to the second collection tank 340. The outlet of the anoxic ecological ditch 2 is connected to the inlet above the second water distribution tank 330 through a connecting pipe 5. The sewage flowing out of the anoxic ecological ditch 2 first enters the second water distribution tank 330, and then enters the inlet above the aerobic nitrification tank 310 from the second water distribution tank 330, and finally enters the aerobic nitrification tank 310 for aerobic biochemical reactions. After the aerobic biochemical reactions are completed, the sewage will enter the second collection tank 340 through the outlet below the aerobic nitrification tank 310. The outlet below the second collection tank 340 is connected to the inlet of the soil infiltration bed 4 through a connecting pipe 5, and the water in the second collection tank 340 can flow into the soil infiltration bed 4 through the connecting pipe 5.

[0082] Embodiment 10

[0083] As Figure 2 shown, this embodiment is a further improvement based on any one of Embodiments 1 to 9, and the specific details are as follows:

[0084] Inside the soil infiltration bed 4, there are a second fine gravel packing layer 410, a second geotextile membrane 420, and a second soil planting layer 430 laid in sequence from bottom to top. Compared with the packing layers in the anoxic ecological ditch 2 and the aerobic ecological ditch 3, the thickness of the second fine gravel packing layer 410 in the soil infiltration bed 4 is smaller. The second soil planting layer 430 is planted with amphibious herbaceous plants 440. Since the water requirement of the amphibious herbaceous plants 440 is not large and the second soil planting layer 430 is relatively thick and less affected, when there is no sewage inflow, the survival of the amphibious herbaceous plants 440 is not a problem either. At both ends of the soil infiltration bed 4 in its length direction, a water inlet and a water outlet are respectively provided at the lower part and the upper part of the second fine gravel packing layer 410. That is, the sewage flowing out of the aerobic ecological ditch 3 enters from the lower part of the second fine gravel packing layer 410 and then flows out from the upper part of the second fine gravel packing layer 410, presenting a plug flow form as a whole, further reducing pollutants, and the effluent flows into the receiving water body.

[0085] Furthermore: The thickness of the second fine gravel packing layer 410 is equivalent to the thickness of the second soil planting layer 430.

[0086] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A waterfront space ecological restoration system for agricultural non-point source pollution, characterized in that: include: An ecological interception ditch (1), an anaerobic ecological ditch (2), an aerobic ecological ditch (3) and a soil infiltration bed (4) are sequentially distributed along the slope surface downward in a limited waterfront slope space, wherein the water inlet and the water outlet of the anaerobic ecological ditch (2), the aerobic ecological ditch (3) and the soil infiltration bed (4) are respectively located at two ends in their respective length directions, and the ecological interception ditch (1), the anaerobic ecological ditch (2), the aerobic ecological ditch (3) and the soil infiltration bed (4) are sequentially connected along the water flow direction.

2. The waterfront space ecological restoration system for coping with agricultural non-point source pollution according to claim 1 is characterized in that: The width of each of the ecological interception ditch (1), the anoxic ecological ditch (2), the aerobic ecological ditch (3) and the soil infiltration bed (4) is 0.5m to 0.8m, and the length of each of the ecological interception ditch (1), the anoxic ecological ditch (2), the aerobic ecological ditch (3) and the soil infiltration bed (4) is 2m to 4m.

3. The waterfront space ecological restoration system for coping with agricultural non-point source pollution according to claim 1 is characterized in that: A water outlet is provided at the upper portion of the ecological interception ditch (1), and aquatic and amphibious plants (110) are arranged in the ecological interception ditch (1).

4. The waterfront space ecological restoration system for coping with agricultural non-point source pollution according to claim 1 is characterized in that: The first fine crushed stone filling layer (211) of the anoxic ecological ditch (2) has a plurality of first flow guide plates (215) arranged vertically along its length direction and used to extend the flow path of water.

5. The waterfront space ecological restoration system for coping with agricultural non-point source pollution according to claim 1 is characterized in that: A slow-release carbon source (216) is added to the first fine crushed stone filler layer (211) of the anoxic ecological ditch (2), and the slow-release carbon source (216) is straw.

6. The waterfront space ecological restoration system for coping with agricultural non-point source pollution according to claim 5 is characterized in that: The anoxic ecological ditch (2) comprises: an anoxic denitrification pool (210), wherein a first fine crushed stone filling layer (211), a first geomembrane (212) and a first soil planting layer (213) are sequentially laid from bottom to top in the anoxic denitrification pool (210), a first drought-tolerant emergent plant (214) is planted on the first soil planting layer (213), and the anoxic denitrification pool (210) is provided with a water inlet and a water outlet at the lower part and the upper part of the first fine crushed stone filling layer (211) at two ends in the length direction thereof, respectively; A first water distribution pool (220) and a first water collection pool (230) are respectively arranged at two ends of the anoxic denitrification pool (210) in the longitudinal direction; the water inlet of the anoxic denitrification pool (210) is connected to the first water distribution pool (220); the water outlet of the anoxic denitrification pool (210) is connected to the first water collection pool (230); the water outlet at the top of the ecological interception ditch (1) is connected to the water inlet at the top of the first water distribution pool (220) via a connecting pipe (5); and the water outlet at the top of the first water collection pool (230) is connected to the water inlet of the aerobic ecological ditch (3) via a connecting pipe (5).

7. The waterfront space ecological restoration system for coping with agricultural non-point source pollution according to claim 1 is characterized in that: A plurality of second flow guide plates (312) arranged vertically and used to extend the flow path of water are arranged in the coarse crushed stone filling layer (311) of the aerobic ecological ditch (3) along its length direction.

8. The waterfront space ecological restoration system for coping with agricultural non-point source pollution according to claim 7 is characterized in that: A plurality of rope-shaped artificial water plants (313) are buried in the coarse crushed stone filling layer (311) along the water flow direction.

9. The waterfront space ecological restoration system for coping with agricultural non-point source pollution according to claim 1 is characterized in that: The aerobic ecological ditch (3) comprises: an aerobic nitrification pool (310), a coarse crushed stone filling layer (311) is laid in the aerobic nitrification pool (310), a planting pot (320) is arranged on the coarse crushed stone filling layer (311), and a second drought-resistant emergent plant (321) is planted in the planting pot (320), and the aerobic nitrification pool (310) is provided with a water inlet and a water outlet at the upper part and the lower part of the coarse crushed stone filling layer (311) at both ends in the length direction thereof; A second water distribution pool (330) and a second water collection pool (340) are respectively arranged at the two ends of the aerobic nitrification pool (310) in the longitudinal direction; the water inlet of the aerobic nitrification pool (310) is connected to the second water distribution pool (330); the water outlet of the aerobic nitrification pool (310) is connected to the second water collection pool (340); the water outlet of the anoxic ecological ditch (2) is connected to the water inlet at the upper part of the second water distribution pool (330) via a connecting pipe (5); and the water outlet at the lower part of the second water collection pool (340) is connected to the water inlet of the soil infiltration bed (4) via a connecting pipe (5).

10. The waterfront space ecological restoration system for coping with agricultural non-point source pollution according to claim 1, characterized in that: The soil infiltration bed (4) comprises a second fine crushed stone filling layer (410), a second geomembrane (420) and a second soil planting layer (430) which are laid in sequence from bottom to top, and aquatic and amphibious herbaceous plants (440) are planted on the second soil planting layer (430). The soil infiltration bed (4) is provided with a water inlet and a water outlet at the lower part and the upper part of the second fine crushed stone filling layer (410) at both ends in the length direction thereof.

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