Subsurface flow constructed wetland and facility agriculture cooperation system

Abstract

The invention relates to the technical field of subsurface flow constructed wetlands and facility agriculture, in particular to a subsurface flow constructed wetland and facility agriculture cooperation system which comprises N constructed wetlands and facility agriculture planting areas, the number of the constructed wetlands is an inverted-T-shaped subsurface flow constructed wetland, the number of the facility agriculture planting areas is N-1, and the number of the facility agriculture planting areas is an inverted-T-shaped facility agriculture planting area. The inverted-T-shaped subsurface flow constructed wetlands and the inverted-T-shaped facility agricultural planting areas are arranged at intervals. According to the subsurface flow constructed wetland and facility agriculture cooperation system, a resource circulation symbiotic system is formed through cooperative operation of the concave-convex subsurface flow constructed wetland and facility agriculture, harmful substances such as COD, a surfactant, escherichia coli and roundworm eggs in water are removed through the subsurface flow constructed wetland, an irrigation water source is provided for facility agriculture production, and the water quality is improved. Wherein the wetland is not provided with an enhanced nitrogen and phosphorus removal area, and meanwhile, the addition of fertilizers required by agricultural planting is reduced, so that the resource saving and environmental protection benefits are realized.

Description

Technical Field

[0001] This invention relates to the field of combined technology of subsurface flow constructed wetlands and temperature-controlled facility agriculture, specifically a synergistic system of controlled-flow subsurface flow constructed wetlands and facility agriculture. Background Technology

[0002] Domestic sewage, generated from people's daily life processes, has a high nitrogen and phosphorus content and has great potential for application in agricultural production.

[0003] However, domestic sewage generally has a large fluctuation in COD and contains certain surfactants, E. coli, and roundworm eggs. When domestic sewage is used directly for irrigation, it poses risks such as clogging the gaps between soil particles, affecting crop growth, and impacting safety and hygiene. Constructed wetlands, as a low-cost ecological treatment method for domestic sewage, utilize the coordinated physical, chemical, and biological processes of a substrate-microorganism-plant complex ecosystem to purify wastewater through filtration, adsorption, co-precipitation, ion exchange, plant absorption, and microbial decomposition. They are widely used in domestic sewage treatment systems.

[0004] Currently, there are application examples of constructed wetland wastewater treatment systems operating in conjunction with agricultural production. However, constructed wetland treatment unit systems occupy a large area, requiring significant land resources. Furthermore, wetland systems suffer from problems such as clogging during long-term operation and inability to function properly in winter. This invention employs a nested structure design of a concave-convex shaped, controllable-flow-rate subsurface flow constructed wetland and temperature-controlled facility agriculture. This effectively expands space utilization, achieving a wetland-to-agricultural land area ratio of 1:3, improving land utilization, reducing land resource requirements, effectively controlling wetland system clogging, ensuring winter operation, and providing continuous and stable heating and insulation for the system. Summary of the Invention

[0005] The present invention provides a subsurface flow constructed wetland and facility agriculture collaborative system, which can control the flow rate, meet the winter operation requirements, and make full use of the construction land space for the construction of constructed wetland sewage treatment system and facility agriculture planting combination.

[0006] The technical solution adopted by this invention to solve its technical problem is: a subsurface flow constructed wetland and facility. An agricultural collaborative system is characterized by including constructed wetlands and facility agriculture planting areas. The constructed wetlands are N "convex"-shaped subsurface flow constructed wetlands, and the facility agriculture planting areas are N-1 inverted "convex"-shaped facility agriculture planting areas. The "convex"-shaped subsurface flow constructed wetlands and the inverted "convex"-shaped facility agriculture planting areas are arranged at intervals.

[0007] A further technical solution of the present invention: the "convex" shaped subsurface flow artificial wetland pool includes a pool body, wetland plants, an inlet valve, a collection pool, an outlet drain valve, a low-level drain valve, and a high-level drain valve; A sewage inlet pipe is connected to the pool body, and the inlet valve is installed on the sewage inlet pipe; Each pool is connected to a collection pool via a primary sewage outlet pipeline, and a secondary sewage outlet pipeline is laid in the collection pool to connect to the facility agriculture planting area.

[0008] Furthermore, the "convex" shaped subsurface flow constructed wetland pool is equipped with multi-point water distribution pipelines, and the input end of the multi-point water distribution pipelines is connected to the sewage input pipe.

[0009] Furthermore: An irregularly shaped agricultural planting area is set up at the left end of the first "convex" shaped subsurface flow constructed wetland.

[0010] Furthermore: An irregularly shaped agricultural planting area is set at the right end of the Nth "convex" shaped subsurface flow constructed wetland.

[0011] Furthermore, multiple sets of water level control valves are installed from bottom to top along the height of the "convex"-shaped subsurface flow constructed wetland, which is connected to the primary sewage output pipeline.

[0012] Furthermore, the water level control valves are provided in three sets. The first set of outlet water level control valves is an outlet drain valve, which is located at the bottom of the "convex" shaped subsurface flow artificial wetland pool. The second set of outlet water level control valves is a low-level drain valve, and the third set of water level control valves is a high-level drain valve.

[0013] Further: Construct greenhouse covers outside artificial wetlands and facility agriculture planting areas.

[0014] The beneficial effects of this invention include: 1. This invention effectively expands the space utilization rate of land, reduces the demand for land resources, increases agricultural income, and replenishes wetland operation and maintenance costs by combining a "convex" shaped subsurface flow artificial wetland sewage purification area and an inverted "convex" shaped facility agriculture planting area. 2. This invention forms a resource recycling and symbiotic system by cooperating with facility agriculture through the concave-convex subsurface flow constructed wetland. The subsurface flow constructed wetland removes harmful substances such as COD, surfactants, E. coli and roundworm eggs from the water, providing irrigation water for facility agriculture production. The wetland does not have a zone for enhanced nitrogen and phosphorus removal, and at the same time reduces the amount of fertilizer required for agricultural planting, thus achieving resource conservation and environmental protection benefits.

[0015] 3. This invention achieves the same efficiency of using winter water in summer and overwintering through the high and low water level operation of the "convex" shaped subsurface flow artificial wetland.

[0016] 4. This invention uses a controllable flow rate and velocity inlet valve at the inlet end of a convex subsurface flow constructed wetland. By increasing the flow velocity within the wetland, the optimal water volume and velocity required for system operation are achieved, thus extending the system's service life.

[0017] 5. This invention provides stable heating and insulation for the entire system by adding a double-layer greenhouse cover to the outside of the system, providing the optimal temperature required for crop growth and wetland operation. Attached Figure Description

[0018] Figure 1 This is a schematic cross-sectional view of the water inlet end of a preferred embodiment of the present invention; Figure 2 This is a schematic cross-sectional view of the water outlet end of a preferred embodiment of the present invention.

[0019] Figure 1 In the middle: 1. Irregularly shaped facility agriculture planting area on the left; 11. Subgrade; 12. Soil layer; 13. Crops; 2. "Convex" shaped subsurface flow artificial wetland; 21. Pool body; 22. Wetland plants; 23. Inlet valve; 3. Inverted "Convex" shaped facility agriculture planting area; 4. N-2 "Convex" shaped subsurface flow artificial wetland pools and N-3 inverted "Convex" shaped facility agriculture planting areas; 5. Irregularly shaped facility agriculture planting area on the right; 6. Greenhouse cover.

[0020] Figure 2 In the middle: 24. Water collection tank; 25. Water outlet and drain valve; 26. Low-level drain valve; 27. High-level drain valve. Detailed Implementation

[0021] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0022] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0023] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0024] Please see Figure 1 and Figure 2The present invention provides a technical solution: a subsurface flow constructed wetland and facility agriculture collaborative system, comprising: a first irregularly shaped agricultural planting area 1, a first "convex" shaped subsurface flow constructed wetland 2, a first inverted "convex" shaped facility agriculture planting area 3, N-2 "convex" shaped subsurface flow constructed wetland pools and N-3 inverted "convex" shaped facility agriculture planting areas 4 (omitted in the middle), the N-1th inverted "convex" shaped facility agriculture planting area 3, the Nth "convex" shaped subsurface flow constructed wetland pool 2, a second irregularly shaped facility agriculture planting area 5, and a greenhouse cover 6.

[0025] Furthermore, the first irregularly shaped facility agriculture planting area 1 includes a base layer 11, a planting soil layer 12, and crops 13. The base layer 11 is made of a mixture of rammed clay and concrete, with a thickness controlled at 15-20cm, providing good load-bearing capacity and impermeability. The planting soil layer 12 is composed of a mixture of humus, garden soil, and perlite in a 3:2:1 ratio, with a thickness of 25-30cm. It is rich in organic matter and has good air permeability, which is conducive to the extension of crop roots. The lower edge of its right protruding area is seamlessly connected to the left shoulder of the first "convex"-shaped subsurface flow artificial wetland pool 2, and the joint is treated with waterproof sealant to prevent sewage leakage. The right edge of its right protruding area is tightly fitted to the left wall of the protruding part of the first "convex"-shaped subsurface flow artificial wetland pool 2, with a gap of no more than 5cm, ensuring structural stability.

[0026] Furthermore, the first "convex" shaped subsurface flow artificial wetland pool 2 includes a "convex" shaped ecological wetland pool body 21, wetland plants 22, inlet valve 23, collection pool 24, outlet drain valve 25, low-level drainage valve 26, and high-level drainage valve 27. The wetland plants 22 are selected from aquatic plants such as reeds, calamus, and cattails, and are planted evenly at a density of 3-5 plants per square meter, with roots penetrating 30-50cm into the substrate layer to enhance microbial attachment and wastewater purification effects. The pool body 21 is made of reinforced concrete, and the inner wall is coated with anti-corrosion and waterproof coating with a thickness of 3-5mm to prevent long-term immersion corrosion. The left side of its protruding portion connects to the right edge of the right protruding area of ​​the first irregularly shaped facility agriculture planting area 1, and the upper wall of the left shoulder connects to the lower edge of the right protruding area; the right side of its protruding portion connects to the right edge of the right protruding area of ​​the first inverted "convex" shaped facility agriculture planting area 3, and the upper wall of the left shoulder connects to the lower edge of the right protruding area. Reinforcing steel bars are installed at all joints with a spacing of 20-30cm to improve the overall structural load-bearing capacity.

[0027] Furthermore, the first inverted "convex" shaped facility agriculture planting area includes a base layer 11, a planting soil layer 12, and crops 13. The material, thickness, and ratio of the base layer and the planting soil layer are the same as those of the first irregularly shaped facility agriculture planting area 1. Crops 13 can be selected as leafy vegetables (such as lettuce and romaine lettuce) or fruit vegetables (such as tomatoes and cucumbers) according to the planting plan, and can be planted in separate zones to improve agricultural yield. The lower edge of its left convex area is connected to the upper wall of the right convex shoulder of the first "convex" shaped subsurface flow artificial wetland 2. The left edge of its left convex area is connected to the right wall of the protruding part of the first "convex" shaped subsurface flow artificial wetland 2. The lower edge of its right convex area is connected to the upper wall of the left convex shoulder of the first "convex" shaped subsurface flow artificial wetland 2. The right edge of its right convex area is connected to the left wall of the protruding part of the first "convex" shaped subsurface flow artificial wetland 2. The joint surfaces are leveled with cement mortar to ensure a tight connection without loosening.

[0028] Furthermore, N-2 convex subsurface flow artificial wetland ponds and N-3 inverted convex facility agriculture planting areas are omitted in the middle, along with the first convex subsurface flow artificial wetland 2 and the first inverted convex facility agriculture planting area 3. The spacing between each unit is controlled at 1-1.5m, with reserved maintenance passages. The passage width is not less than 0.8m, which facilitates later equipment maintenance and crop management.

[0029] Furthermore, the (N-1)th inverted "convex" shaped facility agriculture planting area 3 includes a ground layer 11, a planting soil layer 12, and crops 13. It is connected to the (N-1)th "convex" shaped subsurface flow artificial wetland 2 on the left and to the Nth "convex" shaped subsurface flow artificial wetland 2 on the right. The area where they connect is the same as the first inverted "convex" shaped facility agriculture planting area 3. A drainage ditch is set at the connection point. The ditch is 15-20cm wide and 10-15cm deep, with a perforated drainage pipe inside to prevent water accumulation in the planting area from affecting crop growth.

[0030] Furthermore, the Nth convex subsurface flow constructed wetland 2 includes a convex ecological wetland pool 21, wetland plants 22, an inlet valve 23, a collection pool 24, an outlet drain valve 25, a low-level drainage valve 26, and a high-level drainage valve 27. It connects to the (N-1)th inverted convex facility agriculture planting area 3 on the left and to the second irregularly shaped facility agriculture planting area 5 on the right. The connection areas are the same as the first convex subsurface flow constructed wetland 2. A protective railing, 1.2m high, is installed on the outside of the pool 21, with a railing spacing of 10-15cm to ensure personnel safety.

[0031] Furthermore, the second irregularly shaped facility agriculture planting area 5 includes a ground layer 11, a planting soil layer 12, and crops 13. It is connected to the Nth "convex" shaped subsurface flow artificial wetland 2 on the right side. The area where they are connected is the same as the first inverted "convex" shaped facility agriculture planting area 3. Irrigation water meters are set at the edge of the planting area to monitor the irrigation water consumption in real time, which facilitates water resource regulation.

[0032] The convex-concave shaped controllable flow velocity subsurface flow constructed wetland and facility agriculture collaborative system provided by this invention includes the following operating steps: S1. Employing a concave-convex nested structure, and based on a certain land area and ensuring the resource recycling effect of domestic sewage, the area of ​​the "convex" shaped subsurface flow constructed wetland 2 is rationally allocated to the irregular-shaped facility agriculture planting area 1 on the left end, the irregular-shaped facility agriculture planting area 5 on the right end, and the inverted "convex" shaped facility agriculture planting area 3. For example, when the total land area is 1000㎡, the total area of ​​the "convex" shaped subsurface flow constructed wetland is controlled at about 250㎡, and the total area of ​​the irregular-shaped planting areas on the left and right ends and the inverted "convex" shaped planting area is about 750㎡, accurately achieving a 1:3 wetland to agricultural land area ratio, achieving effective space utilization with a unit area efficiency of 150%. At the same time, according to the crop growth characteristics and market demand, the planting area is divided into a short-term harvest area (leafy vegetables, growth cycle 30-45 days) and a long-term harvest area (fruit and vegetable crops, growth cycle 90-120 days), improving the rationality of the planting layout and the stability of agricultural income.

[0033] S2. Domestic sewage treated by the front-end sewage treatment facilities, meeting the requirements of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002), enters the "convex"-shaped subsurface flow constructed wetland through the inlet pipeline. A multi-point water distribution method is adopted. The inlet pipeline includes a sewage input pipeline and multi-point water distribution pipelines. The sewage input pipeline uses PVC pipes with a diameter of 100-150mm, while the multi-point water distribution pipelines use PE perforated pipes with a diameter of 50-75mm, a pipe wall opening rate of 3%-5%, and a hole spacing of 15-20cm. These are evenly arranged in 3-5 rows along the length of the wetland pool to ensure that the sewage is evenly sprayed onto the wetland substrate surface, avoiding localized water accumulation or uneven water distribution. The sewage input pipeline is equipped with an inlet valve 23 with controllable flow rate and velocity. This valve is an electromagnetic flow control valve, which can be remotely adjusted through an intelligent control system. Based on the actual amount of domestic sewage generated (calculated at an average of 5-10 m³ / 100 m² wetland area per day), the operational requirements of the "convex"-shaped subsurface flow constructed wetland, and the water demand of each planting area, the inlet flow velocity is controlled at 0.05-0.1 m / s, thereby controlling the optimal water volume and flow velocity required for system operation. Preferably, in step b), the flushing velocity is 2-5 times the design hydraulic surface load of the "convex"-shaped subsurface flow constructed wetland, i.e., 0.1-0.5 m / s, and the flushing mode is activated periodically (every 15-20 days) to effectively prevent the substrate pores from becoming clogged.

[0034] S3. Wastewater flows horizontally through the "convex"-shaped subsurface flow constructed wetland 2. The physical, chemical, and biological synergistic effects of the substrate, plants, and microorganisms purify the wastewater before it flows to the collection tank 24 via the primary wastewater outlet pipeline. The wetland substrate employs a layered structure design: the upper layer is a gravel layer with a particle size of 2-5 cm and a thickness of 30-40 cm, primarily serving to filter suspended solids; the middle layer is a zeolite layer with a particle size of 1-2 cm and a thickness of 40-50 cm, utilizing the adsorption properties of zeolite to enhance the removal of pollutants such as COD and ammonia nitrogen; the lower layer is a crushed stone layer with a particle size of 5-10 cm and a thickness of 20-30 cm, facilitating wastewater infiltration and collection. The collection tank 24 is located below the tail end of the "convex"-shaped subsurface flow constructed wetland, with a length equal to 1 / 5-1 / 4 of the wetland tank's length, a width matching the wetland tank, and a depth of 50-80 cm. The bottom of the tank has a 1%-2% slope to facilitate wastewater collection. A primary sewage discharge pipeline is laid in the collection tank 24, extending upwards along the bottom and right side walls of the collection tank to the height of the wetland tank (1.5-3.2 meters). Along the right side wall, from bottom to top, a sewage drain pipeline, a low-level sewage discharge pipeline, and a high-level sewage discharge pipeline are sequentially installed. The sewage drain pipeline is located at the bottom of the collection tank, horizontally aligned with the top of the collection tank, and has a sewage drain valve 25 at its outlet. The low-level sewage discharge pipeline has a low-level drainage valve 26 at its outlet to ensure water level operation during summer. The high-level sewage discharge pipeline has a high-level drainage valve 27 at its outlet to ensure water storage and operation during winter. In extremely cold weather with temperatures below -10℃, 7-10 days before the wetland surface freezes, the water level is raised to 20-30cm from the top of the pool via the high-level drainage valve 27. After a 5-8cm thick ice layer forms on the surface, the wetland water level is lowered to below the low-level drainage valve 26 via the effluent drain valve 25 within 24 hours. This creates a 15-25cm thick air layer between the ice layer and the water (ice layer and packing material), constructing a double-layer insulation structure of ice and air layers to ensure the "convex"-shaped subsurface flow artificial wetland 2 can overwinter normally. The heights of the low-level drainage valve 26 and the high-level drainage valve 27 are set according to the actual wetland pool height, wastewater generation, system operating water volume, etc., with the high-level drainage valve preferably positioned at -0.7 to -1.2 meters and the low-level drainage valve at -1.5 to -2 meters.

[0035] S4. Domestic wastewater, purified by the "convex"-shaped subsurface flow constructed wetland 2, and meeting the "Standards for Irrigation Water Quality" (GB5084-2021) after testing, flows into a collection tank through wastewater discharge pipelines, low-level wastewater output pipelines, and high-level wastewater output pipelines. From there, it is transported via secondary wastewater output pipelines to the irregularly shaped facility agriculture planting area 1 on the left, the irregularly shaped facility agriculture planting area 5 on the right, and the inverted "convex"-shaped facility agriculture planting area 3 for irrigation. The secondary wastewater output pipelines use PVC pipes with a diameter of 75-110mm, laid along the edges of the planting areas. Branch pipelines connect to drip irrigation or sprinkler irrigation equipment. Leafy vegetables are irrigated using sprinkler irrigation at an intensity of 20-30 L / m²·d, with irrigation time selected between 6-8 am; fruit and vegetable crops are irrigated using drip irrigation at an intensity of 30-50 L / m²·d, with irrigation time selected between 6-8 pm to reduce water evaporation loss. Meanwhile, online water quality monitoring equipment is installed at the front end of the secondary sewage output pipeline to monitor indicators such as COD, ammonia nitrogen, total phosphorus, and E. coli in real time. When the indicators exceed the standards, the irrigation valve is automatically closed and the return pipeline is started to guide the sewage back to the front-end sewage treatment facility for reprocessing, thus ensuring the safety of irrigation water.

[0036] A greenhouse cover (6) is constructed outside the concave-convex shaped controlled-flow subsurface flow constructed wetland and facility agriculture collaborative system. The greenhouse cover is made of double-layer hollow glass with a glass thickness of 5-8mm, providing excellent thermal insulation performance. The frame is made of aluminum alloy, which has strong wind resistance. A temperature control system is added inside the greenhouse cover, including heating devices (such as electric heating wires and geothermal coils) and ventilation devices (such as exhaust fans and ventilation windows). The internal temperature is monitored in real time by temperature sensors. When the temperature is below 10℃, the heating devices are automatically activated to raise the temperature to 15-25℃ (the suitable temperature range for crop growth and wetland operation). When the temperature is above 30℃, the ventilation devices are automatically activated to maintain a stable internal temperature, providing continuous and stable heating and insulation for the entire system.

[0037] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A system for the coordinated use of subsurface flow constructed wetlands and facility agriculture, characterized in that, The facility includes artificial wetlands, facility agriculture planting areas and greenhouse covers (6). The artificial wetlands are "convex" shaped subsurface flow artificial wetlands (2) and there are N such artificial wetlands. The facility agriculture planting areas include N-1 inverted "convex" shaped facility agriculture planting areas (3). The "convex" shaped subsurface flow artificial wetlands (2) and the inverted "convex" shaped facility agriculture planting areas (3) are arranged alternately. The "convex" shaped subsurface flow artificial wetland (2) includes a pool body (21), wetland plants (22), an inlet valve (23), a collection pool (24), a primary sewage output pipeline and a secondary sewage output pipeline. A sewage input pipe is connected to the pool body (21), and the inlet valve (23) is installed on the sewage input pipe. A multi-point water distribution pipeline is provided in the pool body (21), and the input end of the multi-point water distribution pipeline is connected to the sewage input pipe. Each pool body (21) is connected to the collection pool (24) through the primary sewage output pipeline. The secondary sewage output pipeline is laid in the collection pool (24), and the secondary sewage output pipeline is connected to the inverted "convex" shaped facility agriculture planting area (3). Multiple sets of water level control valves are installed from bottom to top along the height of the pool body (21) of the "convex" shaped subsurface flow artificial wetland (2) in the water collection pool (24), and the greenhouse cover (6) covers the outside of the artificial wetland and facility agriculture planting area.

2. The subsurface flow constructed wetland and facility agriculture synergistic system according to claim 1, characterized in that: The water level control valve is provided in three sets, namely, the outlet drain valve (25), the low-level drain valve (26) and the high-level drain valve (27). The outlet drain valve (25) is located at the water collection pool (24) at the bottom of the "convex" shaped subsurface flow artificial wetland (2). The low-level drain valve (26) and the high-level drain valve (27) are arranged sequentially upward along the height of the water collection pool (24).

3. The subsurface flow constructed wetland and facility agriculture synergistic system according to claim 1, characterized in that: An irregularly shaped facility agriculture planting area (1) is set at the left end of the first "convex" shaped subsurface flow artificial wetland (2). The irregularly shaped facility agriculture planting area (1) includes a ground layer (11), a planting soil layer (12) and crops (13), and obtains irrigation water through the secondary sewage output pipeline.

4. A subsurface flow constructed wetland and facility agriculture synergistic system according to claim 1 or 3, characterized in that: An irregularly shaped facility agriculture planting area (5) is set at the right end of the Nth "convex" shaped subsurface flow artificial wetland (2). The irregularly shaped facility agriculture planting area (5) includes a ground layer (11), a planting soil layer (12) and crops (13), and obtains irrigation water through the secondary sewage output pipeline.

5. The subsurface flow constructed wetland and facility agriculture synergistic system according to claim 1, characterized in that: The pool body (21) of the "convex" shaped subsurface flow artificial wetland (2) is made of reinforced concrete and the inner wall is coated with anti-corrosion and waterproof coating with a thickness of 3-5mm.

6. The subsurface flow constructed wetland and facility agriculture synergistic system according to claim 1, characterized in that: The wetland plants (22) shall be at least one of reed, calamus and cattail, with a planting density of 3-5 plants per square meter and roots penetrating 30-50 cm into the substrate layer.

7. The subsurface flow constructed wetland and facility agriculture synergistic system according to claim 1, characterized in that: The substrate of the "convex" shaped subsurface flow constructed wetland (2) adopts a layered structure. The upper layer is a gravel layer with a particle size of 2-5cm and a thickness of 30-40cm; the middle layer is a zeolite layer with a particle size of 1-2cm and a thickness of 40-50cm; and the lower layer is a crushed stone layer with a particle size of 5-10cm and a thickness of 20-30cm.

8. The subsurface flow constructed wetland and facility agriculture synergistic system according to claim 1, characterized in that: The sewage input pipe is a PVC pipe with a diameter of 100-150mm. The multi-point water distribution pipeline is a PE material multi-hole pipe with a diameter of 50-75mm, a pipe wall opening rate of 3%-5%, a hole spacing of 15-20cm, and is evenly arranged in 3-5 rows along the length of the pool body (21).

9. The subsurface flow constructed wetland and facility agriculture synergistic system according to claim 1, characterized in that: The greenhouse cover (6) is made of double-layer hollow glass with a glass thickness of 5-8mm.

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