Composite wetland-planting and breeding system based on natural solution and tail water purification method

Abstract

The invention discloses a compound wetland-planting and breeding system based on a natural solution and a tail water purification method.The system comprises two breeding ponds, a farmland buffer area and two wetland buffer areas, the two breeding ponds are arranged between a water inlet canal and a water outlet canal, and the two breeding ponds are the breeding pond 1 and the breeding pond 2 respectively; the two wetland buffer areas are respectively a wetland buffer area 1 and a wetland buffer area 2, the culture pond 1, the wetland buffer area 1, the farmland buffer area, the culture pond 2 and the wetland buffer area 2 are arranged in sequence, and the water inlet canal is used for supplying water to culture of the culture pond; the water outlet channel is used for receiving drained water of the culture pond, the wetland buffer area and the farmland buffer area. The purification capacity of a natural ecological system is fully utilized, purification treatment on the tail water of the culture pond is achieved through a natural solution, and the method is an environment-friendly and low-investment tail water treatment mode.

Description

Technical Field

[0001] The present invention relates to the technical field of landscape ecological restoration, and in particular to a composite wetland-breeding system and a tail water purification method based on natural solutions. Background Art

[0002] The aquaculture industry in coastal areas has gradually become an important economic pillar in various regions, but the pollution problem has also become increasingly serious. The discharge of aquaculture tailwater into the sea that does not meet the standards may threaten the marine ecological structure and cause problems such as eutrophication of seawater. If traditional methods are used to treat aquaculture tailwater, it will not only bring economic burdens to the breeders, but also use some chemical agents for treatment. Although it may be effective in the short term, in the long run, these agents may remain in the water and organisms, posing a serious threat to the ecological environment and food safety. Therefore, exploring more economical and environmentally friendly governance methods and reducing dependence on traditional methods have become urgent needs for the sustainable development of coastal aquaculture.

[0003] Wetlands are unique ecosystems in nature, with rich biodiversity and ecological functions. In order to protect the ecological environment, many coastal areas have carried out pond reclamation and wetland restoration projects for aquaculture ponds. For economic considerations, large-scale pond reclamation and wetland restoration projects will seriously affect the livelihoods of fishermen and regional development. How to maintain ecological functions while gaining economic value is an important issue for the future development of pond aquaculture in coastal areas. While pursuing economic value, pond aquaculture in coastal areas also faces the challenges of tailwater purification and ecological protection. Therefore, it is crucial to balance economic development and environmental protection. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a composite wetland-breeding system and tail water purification method based on natural solutions.

[0005] To achieve the above object, the present invention provides the following technical solutions: A composite wetland-breeding system based on natural solutions, characterized in that it includes two breeding ponds, a farmland buffer zone and two wetland buffer zones arranged between an inlet channel and an outlet channel, wherein the two breeding ponds are breeding pond 1 and breeding pond 2, and the two wetland buffer zones are wetland buffer zone 1 and wetland buffer zone 2, respectively; the breeding pond 1, wetland buffer zone 1, farmland buffer zone, breeding pond 2 and wetland buffer zone 2 are arranged in sequence, the inlet channel is used to supply water to the breeding ponds; the outlet channel is used to receive drainage from the breeding ponds, the wetland buffer zone and the farmland buffer zone.

[0006] Furthermore, water flows from the inlet channel into the breeding pond 1 through the inlet A1, and then flows into the outlet channel through the outlet B1. At the same time, the tail water of the breeding pond 1 also enters the wetland buffer zone 1 through the outlet C1, and the outflow of the wetland buffer zone 1 flows into the outflow channel through the outlet D1, and part of the outflow directly flows into the farmland buffer zone through the outlet E1; similarly, water flows from the inlet channel into the breeding pond 2 through the inlet A2, and then flows into the outflow channel through the outlet B2. At the same time, the tail water of the breeding pond 2 also enters the wetland buffer zone 2 through the outlet C2, and the outflow of the wetland buffer zone 2 flows into the outflow channel through the outlet D2, and part of the outflow of the breeding pond 2 directly flows into the farmland buffer zone through the outlet E2; the water for the farmland buffer zone is provided by the breeding pond 2 and the wetland buffer zone 1, and the outflow is directly discharged into the outflow channel.

[0007] Furthermore, the breeding pond is a freshwater breeding pond, and the breeding water is supplied by the water source of the inlet channel. The breeding tail water is discharged into the wetland buffer zone and the outlet channel. According to the needs of aquaculture, the water depth of the breeding pond is about 1.5 meters. The breeding period is from April to December each year. In spring, when the water temperature is suitable in April, the fry are stocked. After the complete fishing in December, dredging is carried out to clean the silt and residue in the breeding pond to prepare for the next round of breeding. The dredged silt is used to stabilize the embankment and is plowed into the farmland buffer zone for fertilization.

[0008] Furthermore, the water source of the wetland buffer zone comes from the tail water of aquaculture ponds. The water quality is purified by planting emergent economic plants such as reeds, calamus, lotus roots, and submerged plants such as foxtail algae and duckweed. These planted plants have a large biomass, which can purify water quality and enhance carbon sinks while also obtaining certain economic value. The harvested reeds and calamus can be used as animal feed or for making woven products. Lotus roots, water chestnuts, and water caltrops all have high edible and economic value. For the wetland buffer zone, dredging is carried out every 2-3 years to ensure the purification capacity of the wetland buffer zone, remove the silt and humus sediments after the death of aquatic plants, and maintain the ecological balance of the wetland buffer zone. The dredged bottom mud can be plowed into the farmland buffer zone for fertilization.

[0009] Furthermore, when laying out the wetland buffer zone, in order to take into account the purification capacity and stability of the ecosystem and the accommodation for the drainage of the aquaculture ponds, and taking into account multiple factors such as atmospheric precipitation evaporation, the water depth of the wetland buffer zone is about 0.6-0.8 meters, and the area ratio of the aquaculture pond to the wetland buffer zone is 1:1.5.

[0010] Furthermore, the farmland buffer zone adopts a rice-wheat rotation model, in which irrigation water comes from aquaculture ponds, and crops absorb nutrients in the aquaculture tail water. At the same time, the crops also obtain the nutrients needed for their own growth. The remaining irrigation water comes from the adjacent wetland buffer zone, and the effluent is discharged into the outlet channel. Among them, the rice planting time is approximately from June to November. During this period, the farmland has a large water demand and a strong ability to absorb nutrients in sewage. After harvesting, the dredged sludge from the aquaculture ponds and wetland buffer zones is plowed into the farmland buffer zone to fertilize the fields.

[0011] Furthermore, in order to take into account the purification capacity and economic benefits of the farmland ecosystem, the area ratio of the breeding pond to the farmland buffer zone is 1:2. This breeding model greatly reduces the use of pesticides and fertilizers, and the resulting agricultural product production process is more green and low-carbon. Through precise positioning and marketing, it can form a brand effect, lead the green development of ecological agriculture, and further promote local economic development.

[0012] Furthermore, the water inlet channel is provided with two water outlets, which are used to supply aquaculture water to two breeding ponds respectively; the water outlet channel is provided with five water outlets, which are used to receive the outflow from the breeding ponds, wetland buffer zone and farmland buffer zone respectively; the water outlet channel is planted with emergent economic plants such as reeds and calamus to stabilize the embankment and absorb nutrients such as nitrogen and phosphorus.

[0013] A method for purifying tailwater of a composite wetland-cultivation system based on a natural solution comprises the following steps: S1. Conduct an overall assessment of the target area: Before implementation, assess the original local planting and breeding patterns, natural ecological conditions, agricultural resources, etc. in the target area to ensure that it is in line with local actual conditions and achieve a win-win situation for economic development and ecological protection; S2. Construction of breeding ponds: The breeding ponds adopt freshwater breeding, and the breeding time is from April to December each year. Ecological breeding is implemented. By controlling the feed input, the water quality of the breeding ponds is controlled at around Class V water. Its output is about 2 / 3 of the output of general breeding ponds; S3. Construct wetland buffer zone: The wetland buffer zone purifies water quality by planting wetland economic plants such as reed, lotus root, calamus, water chestnut, and water caltrop. These plants can effectively remove nutrients such as nitrogen and phosphorus in tailwater and have economic value. S4. Construct farmland buffer zone: The farmland buffer zone further reduces the pollutant content in the aquaculture tailwater through the absorption of nutrients in the sewage by crops, which not only provides nutrients for crops but also purifies the water quality, thus achieving the common development of aquaculture and environmentally friendly agriculture. At the same time, the silt in the aquaculture pond and wetland buffer zone is plowed into the farmland buffer zone to fertilize the fields. S5. Set up inlet and outlet channels: control the inflow and outflow of water and the flow of water sources between different areas. The inlet channel is used to provide water for the breeding ponds, and the outlet channel is used to receive the outflow of the breeding ponds, wetland buffer zone, and farmland buffer zone. Appropriately plant emergent economic plants such as reeds and calamus in the outlet channel to obtain economic value while further absorbing nutrients in the outlet channel; S6. Conduct scientific monitoring and evaluation regularly: After the aquaculture tail water is purified in the wetland buffer zone and the farmland buffer zone, in order to ensure that the water quality meets the discharge standards, that is, the effluent quality reaches Class III water, various water quality indicators are monitored regularly, data changes are recorded, purification results are analyzed, and relevant measures are adjusted in time according to the evaluation results.

[0014] The beneficial effect of the present invention is that the method of the present invention fully utilizes the purification capacity of the natural ecosystem and realizes the purification treatment of the tail water of the aquaculture pond with a natural solution, which is an environmentally friendly and low-investment tail water treatment method. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the system in the present invention.

[0016] Figure 2 It is a landscape schematic diagram of the system in the present invention. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below in conjunction with the embodiments and drawings. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0018] This example is based on the aquaculture ponds in the coastal zone of Yancheng. In recent years, the area of ​​aquaculture ponds in the coastal zone of Yancheng has continued to increase, reaching nearly 1.15 million mu. At the same time, the amount of aquaculture wastewater has also been increasing, but the policy requirements for environmental protection of aquaculture activities have been continuously improved. According to the "Jiangsu Province Pond Aquaculture Tail Water Discharge Standard", the use of traditional methods by aquaculture ponds in the coastal zone of Yancheng requires a lot of money to ensure that the aquaculture tail water meets the discharge standards, in order to deal with the tail water discharge problem more economically and effectively.

[0019] As shown in the figure, an embodiment of the present invention provides a composite wetland-breeding system based on natural solutions, including breeding ponds, wetland buffer zones, and farmland buffer zones.

[0020] The breeding pond is provided with an inlet A1 and outlets B1 and C1, wherein A1 connects the inlet channel and the breeding pond to meet the water demand of the breeding pond, the outlet B1 connects the breeding pond and the outlet channel to discharge the breeding tail water, and the outlet C1 connects the breeding pond and the wetland buffer zone to discharge the breeding tail water into the wetland buffer zone; In this embodiment, the breeding pond area is about 200 mu, about 665 meters long, about 200 meters wide, and about 1.5 meters deep, accounting for about 30% of the total area of ​​the total system. The breeding pond is freshwater breeding, and the fish are stocked when the water temperature is suitable in April each year, and the farmed fish are completely caught in December. No breeding is carried out from January to March. The breeding pond implements an ecological breeding mode, and the water quality of the breeding tail water is controlled within Class V of the "Surface Water Environmental Quality Standard" by controlling the release of fish feed. Therefore, the output of the breeding pond is about 2 / 3 of that of a general breeding pond. After the end of the breeding cycle each year, the breeding pond is thoroughly cleaned to clean the silt and residue therein. The cleaning depth is about 10-15 cm, and the silt clearing volume is about 20,000 cubic meters. The cleaned silt is used to reinforce the embankment of the breeding pond, and can also be plowed into the farmland buffer zone for fertilization.

[0021] In this embodiment, the wetland buffer zone has an area of ​​about 300 mu, a length of about 665 meters, a width of about 300 meters, a water depth of 0.6 meters, and accounts for 30% of the total area of ​​the system. The area ratio to the aquaculture pond is 1.5:1. The wetland buffer zone is provided with an inlet C1 and outlets D1 and E1, wherein the inlet C1 connects the aquaculture pond and the wetland buffer zone to receive the aquaculture tail water of the aquaculture pond, the outlet D1 is used to discharge the water in the wetland buffer zone into the outlet channel, and the outlet E1 is used to discharge the water in the wetland buffer zone into the farmland buffer zone.

[0022] In this embodiment, in order to purify sewage, various plant communities are planted in the wetland buffer zone. According to the local aquatic environment and purification needs, emergent plants such as reeds, calamus, and lotus roots are planted in artificial wetlands. Plants such as reeds and calamus have strong purification capabilities. The symbiotic effect of their roots and microorganisms can filter, degrade and transform organic matter, nitrogen, phosphorus and other pollutants in the tail water. According to investigations and calculations, the interception rate of reeds for total nitrogen and total phosphorus can reach more than 70%. Through the absorption and purification of reeds, nearly half of the total phosphorus and total nitrogen in the aquaculture tail water can be absorbed. Planting calamus in the wetland buffer zone can further effectively absorb nutrients in the water body and reduce the total nitrogen and total phosphorus content. Planting lotus roots can effectively regulate and purify water quality, and can also increase the biodiversity of the wetland and the stability of the ecosystem. At the same time, these plants, as economic crops, have high economic value and increase their economic income.

[0023] In this embodiment, submerged algae such as golden duckweed and foxtail algae are planted in the wetland buffer zone, which can effectively absorb nutrients in the water body and provide a food source for aquatic animals. Some benthic animals such as snails and shellfish can also be released in the wetland buffer zone to increase the biodiversity of the artificial wetland. In this embodiment, the wetland buffer zone is subject to regular human management and monitoring to ensure its ecological function and the stability of the ecosystem. In order to avoid the problems of excessive biomass and excessive sediment accumulation in the wetland buffer zone, according to investigation and calculation, the wetland buffer zone is dredged every two years, and the dredged silt can be used to reinforce the embankment and plowed in the farmland buffer zone to fertilize the field. In order to prevent excessive accumulation of biomass, the reeds in the wetland are harvested at the end of October each year. The harvested reeds can be used as poultry feed or for weaving baskets and other supplies, and new reeds are planted in April of the following year.

[0024] In this embodiment, the farmland buffer zone is about 400 mu, about 665 meters long and about 400 meters wide, accounting for 40% of the entire system area, and the area ratio to the breeding pond is 2:1. It is provided with water inlets E1, E2 and water outlet F1, wherein E1 connects the wetland buffer zone and the farmland buffer zone, E2 connects the farmland buffer zone and the breeding pond, and is used to provide irrigation water for the farmland, and the water outlet F1 is used to discharge the water in the farmland buffer zone into the outlet channel.

[0025] In this embodiment, the farmland is planted in a rice-wheat rotation mode, with the rice planting period from June to November each year and the wheat planting period from December to mid-to-late May of the following year. During the rice planting period, especially the rice irrigation period, that is, from June to October, the farmland has a large water demand, with an average irrigation volume of 2,000 cubic meters per day. The farmland also has a strong ability to absorb nutrients, and can absorb about 4,000 kilograms of carbon and 2,000 kilograms of phosphorus during rice planting, greatly reducing the nutrient concentration in the aquaculture tail water. After the rice is harvested in November, the silt dredged from the aquaculture pond and wetland buffer zone is plowed into the farmland buffer zone to fertilize the field.

[0026] In this embodiment, the water inlet channel is used to supply water to the breeding pond. Water enters the breeding pond through the water inlet A1. The water inlet channel is about 2 meters wide and about 1,500 meters long. According to actual conditions, other water inlets can be set in the water inlet channel to ensure the stability of the entire system. In this embodiment, the outlet channel is provided with outlets B1, D1, and F1, outlet B1 is used for drainage of the breeding pond, outlet D1 is used for drainage of the wetland buffer zone, and outlet F1 is used for drainage of the farmland buffer zone; In this embodiment, the outlet channel is about 4 meters wide, about 1500 meters long, and about 1 meter deep. Reeds, calamus and other emergent economic crops are planted in the outlet channel, which not only beautifies the environment but also purifies the water quality.

[0027] In this embodiment, the area ratio of the breeding pond, farmland buffer zone, and artificial wetland is 1:1.5:2, and the arrangement order of the breeding pond, wetland buffer zone, and farmland buffer zone constitutes a system, and an inlet channel and an outlet channel are provided. At the same time, by setting up a water quality monitoring point, the water quality of the outlet is regularly monitored, the data changes are recorded, the purification results are analyzed, and the relevant measures are adjusted in time according to the evaluation results to ensure the effective purification of the aquaculture tail water.

[0028] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above-mentioned technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also regarded as the protection scope of the present invention.

Claims

1. A composite wetland-farming system based on natural solutions, characterized in that: It includes two breeding ponds, a farmland buffer zone and two wetland buffer zones arranged between an inlet channel and an outlet channel, wherein the two breeding ponds are breeding pond 1 and breeding pond 2, and the two wetland buffer zones are wetland buffer zone 1 and wetland buffer zone 2. The breeding pond 1, wetland buffer zone 1, farmland buffer zone, breeding pond 2 and wetland buffer zone 2 are arranged in sequence, and the inlet channel is used to supply water to the breeding ponds; the outlet channel is used to receive drainage from the breeding ponds, the wetland buffer zone and the farmland buffer zone.

2. A composite wetland-breeding system based on natural solutions according to claim 1, characterized in that: The water source flows from the inlet channel into the breeding pond 1 through the inlet A1, and then flows into the outlet channel through the outlet B1. At the same time, the tail water of the breeding pond 1 also enters the wetland buffer zone 1 through the outlet C1, and the outflow of the wetland buffer zone 1 flows into the outlet channel through the outlet D1, and part of the outflow directly flows into the farmland buffer zone through the outlet E1; similarly, the water source flows from the inlet channel into the breeding pond 2 through the inlet A2, and then flows into the outlet channel through the outlet B2. At the same time, the tail water of the breeding pond 2 also enters the wetland buffer zone 2 through the outlet C2, and the outflow of the wetland buffer zone 2 flows into the outlet channel through the outlet D2, and part of the outflow of the breeding pond 2 directly flows into the farmland buffer zone through the outlet E2; the water for the farmland buffer zone is provided by the breeding pond 2 and the wetland buffer zone 1, and the outflow is directly discharged into the outlet channel.

3. A composite wetland-breeding system based on natural solutions according to claim 1, characterized in that: The aquaculture pond is a freshwater aquaculture pond. The aquaculture water is supplied by the water source of the inlet canal. The aquaculture tail water is discharged into the wetland buffer zone and the outlet canal. The water depth of the aquaculture pond is 1.5 meters. The aquaculture period is from April to December each year. After the fish are fully harvested in December, dredging is carried out. The dredged silt is used to stabilize the embankment and is plowed into the farmland buffer zone for fertilization.

4. A composite wetland-farming system based on natural solutions according to claim 1, characterized in that: The water source of the wetland buffer zone comes from the tail water of aquaculture ponds. The water quality is purified by planting emergent economic plants and submerged plants. These plants can not only purify the water quality and enhance carbon sinks, but also obtain certain economic value. For the wetland buffer zone, dredging is carried out every 2-3 years to ensure the purification capacity of the wetland buffer zone. The dredged sludge can be plowed into the farmland buffer zone for fertilization.

5. A composite wetland-breeding system based on natural solutions according to claim 4, characterized in that: The water depth of the wetland buffer zone is 0.6-0.8 meters, and the area ratio of the breeding pond to the wetland buffer zone is 1:1.

5.

6. A composite wetland-farming system based on natural solutions according to claim 1, characterized in that: The farmland buffer zone is a rice-wheat rotation model, in which irrigation water comes from aquaculture ponds, and crops absorb nutrients in aquaculture tail water, while crops also obtain nutrients needed for their own growth. The remaining irrigation water comes from the adjacent wetland buffer zone, and the effluent is discharged into the outlet channel. Among them, the rice planting period is from June to November. During this period, the farmland has a large water demand and a strong ability to absorb nutrients in sewage. After harvesting, the dredged sludge from the aquaculture ponds and wetland buffer zones is plowed into the farmland buffer zone to fertilize the fields.

7. A composite wetland-farming system based on natural solutions according to claim 6, characterized in that: The area ratio of the breeding pond to the farmland buffer zone is 1:

2.

8. The composite wetland-farming system based on natural solutions according to claim 1, characterized in that: The water inlet channel is provided with two water outlets, which are used to supply aquaculture water to two breeding ponds respectively. The water outlet channel is provided with five water outlets, which are used to receive the outflow from the breeding ponds, wetland buffer zone and farmland buffer zone respectively. Emergent economic plants are planted in the water outlet channel to stabilize the embankment and absorb nutrients.

9. A tailwater purification method of a composite wetland-breeding system based on natural solutions, characterized in that: The system according to any one of claims 1 to 8 comprises the following steps: S1. Conduct an overall assessment of the target area: Before implementation, assess the original local farming and breeding patterns, natural ecological conditions, and agricultural resources in the target area to ensure that it is in line with local conditions and achieves a win-win situation for economic development and ecological protection; S2. Construction of breeding ponds: The breeding ponds adopt freshwater breeding, and the breeding time is from April to December each year. Ecological breeding is implemented. By controlling the feed input, the water quality of the breeding ponds is controlled at around Class V water. Its output is 2 / 3 of the output of general breeding ponds; S3. Construction of wetland buffer zone: Wetland buffer zone purifies water quality by planting wetland economic plants, which can remove nutrients in tailwater and have economic value; S4. Construct farmland buffer zone: The farmland buffer zone further reduces the pollutant content in the aquaculture tailwater through the absorption of nutrients in the sewage by crops, which not only provides nutrients for crops but also purifies the water quality, thus achieving the common development of aquaculture and environmentally friendly agriculture. At the same time, the silt in the aquaculture pond and wetland buffer zone is plowed into the farmland buffer zone to fertilize the fields. S5. Set up inlet and outlet channels: control the inflow and outflow of water and the flow of water sources between different areas. The inlet channel is used to provide water for the aquaculture ponds, and the outlet channel is used to receive the outflow of the aquaculture ponds, wetland buffer zones, and farmland buffer zones. Emergent economic plants are planted in the outlet channels to obtain economic value and further absorb nutrients in the outlet channels; S6. Conduct scientific monitoring and evaluation regularly: After the aquaculture tail water is purified in the wetland buffer zone and the farmland buffer zone, in order to ensure that the water quality meets the discharge standards, that is, the effluent quality reaches Class III water, various water quality indicators are monitored regularly, data changes are recorded, purification results are analyzed, and relevant measures are adjusted in time according to the evaluation results.

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