Artificial wetland purification system and method

Abstract

The invention relates to the technical field of ecological water treatment, in particular to an artificial wetland technology comprising a two-stage collaborative purification system and a dynamic regulation and control purification method. The system comprises an upstream ecological regulation and storage circulation unit which is composed of n regulation and storage ponds connected in series, a snake-shaped water flow channel is formed in each pond in a manner that spur dikes are staggered by 85-95 degrees, and the hydraulic retention time is prolonged to 36-48 hours; the downstream ecological purification unit comprises an ecological island, a zoning type purification filter bed and a three-level nutrition cascade ecological gain pond which are connected in parallel. The overall ammonia nitrogen / total phosphorus removal rate reaches 70% and 60% respectively, the bird inhabiting density is increased to 3.8 birds per hectare, and the aeration energy consumption is reduced. The invention solves the problems of low hydraulic efficiency, weak ecological function and response lag of the traditional wetland, and is suitable for pollution treatment and ecological restoration of rivers and lakes.

Description

Technical Field

[0001] The present invention relates to the field of ecological water treatment technology, and specifically to an artificial wetland technology comprising a two-stage collaborative purification system and a dynamic control purification method, which is used to improve pollutant removal efficiency and ecosystem service functions. Background Art

[0002] Constructed wetland technology, as a green infrastructure combining ecological restoration and wastewater treatment, has become a research hotspot in water environment management. While traditional constructed wetland systems can remove pollutants through plant absorption, microbial degradation, and substrate filtration, their effectiveness is limited by technical bottlenecks such as short hydraulic retention time, uneven dissolved oxygen distribution, and limited biodiversity. This is particularly true when addressing highly nitrogen and phosphorus-contaminated water bodies, where widespread issues include large fluctuations in pollutant removal rates, limited ecosystem service capabilities, and insufficient operational stability.

[0003] Existing constructed wetland systems often utilize a single-stage series or parallel layout, resulting in a linear water flow path. This can lead to short-circuit dead zones in upstream areas and reduced organic matter concentrations in downstream areas, which in turn weakens microbial metabolic activity. Furthermore, traditional wetland systems underutilize topographical features and fail to establish a multi-stage hydraulic circulation system, limiting the water's reoxygenation capacity and hindering the growth and reproduction of aerobic microbial communities.

[0004] In the ecological purification phase, existing technologies often employ single-function purification units, such as those relying solely on plant absorption or substrate adsorption, lacking a synergistic mechanism for biological manipulation and habitat creation. Furthermore, traditional wetland systems are insufficiently designed to adapt to topographical characteristics and fail to construct multi-stage treatment units based on surface runoff path analysis, limiting the effectiveness of cascaded pollutant degradation.

[0005] In response to the above-mentioned technical deficiencies, this field urgently needs to break through the following technical bottlenecks: first, build an intelligent hydraulic control system to achieve dynamic matching of hydraulic retention time and dissolved oxygen concentration; second, develop a multi-stage collaborative purification system to enhance biodiversity through terrain reshaping and habitat creation; third, establish a dual optimization mechanism for pollutant removal and ecosystem service functions to break through the single function limitations of traditional technologies.

[0006] This invention addresses these needs. By deeply integrating wetland terrain analysis with hydraulic regulation technology, it innovatively proposes a two-level collaborative processing unit architecture. This provides an innovative solution for the intelligent upgrading of constructed wetland technology and the improvement of its ecological benefits. Summary of the Invention

[0007] 1. Technical Issues 1. The artificial wetland system has low hydraulic efficiency and weak ecological function; 2. Lack of dynamic control strategies based on multi-source data.

[0008] 2. Technical Solution In order to solve the above problems, the present invention provides an artificial wetland purification system, comprising: The upstream ecological storage and circulation unit consists of n series-connected storage ponds (n>1). Adjacent storage ponds are connected by culverts and sluice gates. Spur dikes are staggered in the ponds perpendicular to the main water flow axis to form a serpentine water channel. Downstream ecological purification unit, including parallel-connected ecological island, ecological purification filter bed and ecological gain pond; The coordinated connection components connect the end of the upstream ecological storage and circulation unit with the beginning of the downstream ecological purification unit through a culvert, and a pump station is set up at the end of the downstream ecological purification unit to regulate the water level.

[0009] Preferably, the layout angle of the spur dike is 85°-95°, and an ecological floating island array is set on the waterside of the spur dike, and the ecological floating island array is planted with plants that remove nitrogen and phosphorus.

[0010] Preferably, the dead water area of ​​the regulating reservoir is provided with a solar aeration system, and the aeration intensity of the solar aeration system is dynamically adjusted based on feedback from a dissolved oxygen sensor.

[0011] Preferably, the slope ratio of the ecological island is 1:8-1:12, the top height is 1 m above the normal water level, and berry shrubs are planted on the surface.

[0012] Preferably, the berry shrubs include paper mulberry and pyracantha.

[0013] Preferably, the ecological purification filter bed comprises: In the shallow water area with a water depth of 0.5–0.7 m, a belt of emergent plants is laid out, including a complex rhizosphere oxygen community of reeds and cattails; In the deep water area with a water depth of 0.7–1.0 m, a submerged-floating leaf plant cooperative zone is arranged, including a combination of Vallisneria and Water Lily.

[0014] Preferably, the ecological gain pond comprises: Vallisneria and water shield are planted in deep water areas; Mix wild water chestnuts and wild rice stems in shallow water; A three-level trophic cascade system consisting of plankton, fish, shrimp, shellfish, and filter-feeding fish is constructed in the ecological gain pond.

[0015] Preferably, the culvert is equipped with a water level sensor and an automatic opening and closing device to dynamically adjust the water level difference according to the upstream water flow and downstream purification requirements.

[0016] On the other hand, the present invention also provides an artificial wetland purification method, which is implemented based on the above artificial wetland purification system and includes the following steps: S1. Extend the water flow path by more than 30% by staggering spur dikes at 85°-95°; S2. Construct a three-level trophic cascade system in the ecological gain pond, with a stocking density of ≥ 5 per m 2 Filter-feeding shellfish and density ≤ 0.5 kg / m 3 filter-feeding fish; S3. Dynamically adjust the solar aeration intensity based on dissolved oxygen data and control the discharge volume of the pump station through water level sensor feedback.

[0017] 3. Beneficial Effects This invention uses serpentine flow channels formed by staggered 85°-95° ​​spur dikes within the upstream reservoir to extend the hydraulic retention time to 36-48 hours, increasing the contact efficiency between pollutants and plants / microorganisms by over 50%. Furthermore, the turbulent effect induced by the spatial arrangement of the spur dikes enhances dissolved oxygen diffusion, resulting in an ammonia nitrogen removal rate of 70%, fundamentally addressing the low hydraulic efficiency of traditional wetlands. Furthermore, dynamic solar aeration control based on real-time dissolved oxygen feedback stabilizes the dissolved oxygen concentration in the dead water zone within a constant range. This not only prevents the secondary release of pollutants caused by anaerobic environments, but also reduces energy waste by adjusting the aeration intensity on demand compared to a fixed mode, achieving a dual breakthrough in energy conservation and pollution control.

[0018] What is even more remarkable is the systematic proliferation of ecological service functions: on the one hand, the berry shrubs (paper mulberry / pyracantha) of the ecological island and the three-level trophic cascade (plankton → snails → filter-feeding fish) of the gain pond synergistically attract birds, bringing the habitat density to 3.2 birds per hectare; on the other hand, the emergent plants (reeds / cattails) and submerged plants (vallisneria / water lilies) arranged in zones according to water depth gradients have constructed a ternary symbiotic system of rhizosphere oxidation-matrix adsorption-microbial degradation, with a total phosphorus removal rate of up to 60%, significantly enhancing the ecological self-purification capacity.

[0019] The collaborative optimization of water level linkage control and biological manipulation in the present invention has achieved remarkable results: the culvert dynamically adjusts the water level difference according to the inflow flow, and the pump station maintains the optimal water depth, so that submerged plants have sufficient light. Combined with the gradient breeding of filter-feeding shellfish and fish, the survival rate is increased to 85%, forming a sustainable ecological purification closed loop.

[0020] In summary, the present invention takes hydraulic regulation as the foundation, biological proliferation and efficiency enhancement, and intelligent collaborative optimization as the core, and simultaneously achieves efficient degradation of pollutants, ecosystem leap and refined control of energy consumption, completely bridging the contradiction between pollution control and ecological functions in traditional technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] This manual includes the following drawings, which show the following contents: Figure 1 This is a schematic structural diagram of a purification system according to a first embodiment of the present invention; In the figure: 1. Reservoir; 2. Culvert; 3. Spur dike; 4. Water flow channel; 5. Ecological island; 6. Ecological purification filter bed; 7. Ecological gain pond; 8. Pumping station; 9. Aeration system; 10. Ecological floating island. DETAILED DESCRIPTION

[0022] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0023] Example 1: This embodiment provides an artificial wetland purification system. Taking a wetland restoration project at an estuary in the lower reaches of the Yangtze River as an application scenario, the system covers an area of ​​about 15 hectares and has a designed daily water treatment capacity of 3,000 cubic meters. The upstream ecological storage and circulation unit consists of four series-connected storage tanks 1. The area of ​​a single storage tank 1 is about 200 square meters and the depth is 1.5 meters. The pools are connected by a steel culvert 2 with a width of 1.5 meters, and the gate opening and closing stroke is controlled at 0-100 cm. A spur dike 3 is arranged vertically along the main water flow direction in the pool. After fluid mechanics simulation optimization, the angle of the spur dike 3 is set to 89.3°±1.5°. The spur dike 3 adopts a reinforced concrete structure with a top elevation of 0.3 meters above the normal water level. It is set at intervals to form a serpentine water flow channel 4 with a total length of 210 meters, which extends the water flow path by 42% compared to the straight-line distance.

[0024] An array of 10 ecological floating islands was installed on the waterfront side of Spur Dike 3. The island frames are made of high-density polyethylene, with individual modules measuring 1 meter by 1 meter. Reeds and cattails planted on the islands were sourced from a local wetland nursery. Twelve solar aeration systems were installed in the backwater area of ​​Reservoir 1. Each system is equipped with a 200-watt monocrystalline silicon photovoltaic panel and a 2.2-kilowatt oil-free air compressor. Aeration intensity is monitored in real time using a Hach HQ40d dissolved oxygen sensor, which automatically increases aeration levels when dissolved oxygen levels fall below the specified value.

[0025] The downstream ecological purification unit adopts a parallel layout, as follows: Ecological Island 5 was constructed using excavated earth from the project, with a base area of ​​120 square meters and a side slope of 1:10. The top of the island was set at 1.05 meters above the normal water level, and 330 mulberry and pyracantha trees were planted on the surface, with 0.6-meter spacing between them.

[0026] The ecological purification filter bed 6 is divided into shallow water area and deep water area: the water depth in the shallow water area is 0.65 meters, and the planting density is 8 reeds per square meter and 4 cattails per square meter, forming a complex rhizosphere oxidation community; the water depth in the deep water area is 0.88 meters, the planting coverage rate of Vallisneria reaches 75%, and water lilies are arranged at a spacing of 1.2 meters.

[0027] The bottom of Ecological Gain Pond 7 is sloped to create deep and shallow water areas. When the water level at Pump Station 8 is 0.78 meters, the water depth in the deep water area is 0.88 meters. Vallisneria and water shield are planted in the deep water area of ​​Ecological Gain Pond 7, while wild water chestnuts and wild rice stems are mixed in the shallow water area, with planting densities of 6 plants per square meter and 4 plants per square meter, respectively. The three-level trophic cascade system constructed in the pond includes: a plankton proliferation area, a filter-feeding shellfish breeding area, and a filter-feeding fish breeding area. Optionally, the algae density in the plankton proliferation area is 1.2×10 5 per liter, the density of snails in the filter-feeding shellfish breeding area is 7.3 per square meter, and the density of silver carp in the filter-feeding fish breeding area is 0.47 kilograms per cubic meter.

[0028] In the collaborative connection component, the culvert 2 is equipped with a Siemens ultrasonic water level meter with a range of 0-2 meters. According to the data of the upstream water inlet flow sensor, when the flow exceeds 12 cubic meters per hour, the automatic opening and closing device increases the gate opening to 85%. A submersible pump station 8 with a drainage capacity of 10 cubic meters per hour is set at the downstream end. The water level of the pump station 8 is maintained within the range of 0.78±0.05 meters through a PID controller, thereby realizing dynamic water level regulation. The automatic opening and closing device can adopt a winch hoist, a hydraulic hoist, etc. As long as the gate can be automatically opened and closed, this technology has long been maturely applied in water conservancy projects. Therefore, its specific structure and working principle will not be repeated in this embodiment.

[0029] In this embodiment, the serpentine water flow channel 4 is used to extend the hydraulic retention time to 45 hours. The three-level nutrient cascade system attracts seven bird species, including night herons and kingfishers, to inhabit, with a density of 3.8 birds per hectare. The ammonia nitrogen and total phosphorus removal rates are 70% and 60% respectively, which have obvious advantages over industry standards.

[0030] Example 2: This embodiment provides an artificial wetland purification method, which is implemented based on the purification system of the first embodiment.

[0031] Specifically, a total station was used to precisely locate the position of Spur Dike 3, ensuring a mean angle of 89.6° with the main flow axis, with a standard deviation of 0.8°. Velocity profilers measured the original straight path, extending from 183 meters to 257 meters, a 40.4% increase. The turbulence intensity of the water flow increased to 0.28, boosting oxygen mass transfer efficiency and improving the uniformity of dissolved oxygen distribution by 62%, creating a favorable foundation for downstream biomass.

[0032] Implementing gradient biological colonization in Ecological Gain Pond 7: Plankton proliferation: diatoms and green algae mixed algae were released to a density of 1.5×10 5 per liter; For filter-feeding shellfish, select river snails (shell height 3.5 ± 0.3 cm) and river clams (shell length 2.8 ± 0.2 cm) at densities of 6.8 and 5.2 per square meter, respectively, for a total density of 12 per square meter. Stocking of filter-feeding fish: silver carp (body length 15±2 cm) and bighead carp (body length 18±2 cm) were released in a ratio of 3:2, with a biomass density of 0.49 kg per cubic meter.

[0033] When the dissolved oxygen sensor detects that the dissolved oxygen level is lower than 3.9 mg / L for 20 consecutive minutes, the DSP controller instructs to increase the aeration intensity to 1.15 liters per minute per cubic meter and restore the dissolved oxygen level to 5.1 mg / L within 2 to 3 hours; When the water level sensor detects that the water depth downstream exceeds 1.02 meters, the drainage capacity of pump station 8 is increased from 7 cubic meters per hour to 11 cubic meters per hour, ensuring that the water level drops to about 0.78 meters within 24 hours.

[0034] This embodiment significantly improves the system's shock load resistance through the aforementioned method. Even under extreme rainstorm conditions, where the inflow suddenly increased by 120%, the ammonia nitrogen removal rate remained at 70%. The natural proliferation rate of shellfish reached 23.5%, with a survival rate of 91.2%. Energy-saving analysis showed a 39.7% reduction in aeration energy consumption.

[0035] In summary, this invention significantly extends hydraulic retention time (HRT) to 36–48 hours by creating serpentine flow channels (4) through upstream staggered spur dikes (3) at 85–95° angles. Combined with a downstream three-stage nutrient cascade system, this achieves a 70% ammonia nitrogen removal rate and a 60% total phosphorus removal rate. This three-in-one model of "structural optimization, intelligent perception, and precise regulation" overcomes the three bottlenecks of traditional wetlands: low hydraulic efficiency, weak ecological function, and delayed response, providing an innovative paradigm for water ecological management.

[0036] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made thereto. Therefore, such modifications and improvements, without departing from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. Artificial wetland purification system, characterized in that, include: The upstream ecological storage and circulation unit is composed of n series-connected storage tanks (1) where n>1, adjacent storage tanks (1) are connected by culvert gates (2), and spur dikes (3) are arranged in a staggered manner perpendicular to the main water flow axis in the tank to form a serpentine water flow channel (4); Downstream ecological purification unit, including an ecological island (5), an ecological purification filter bed (6) and an ecological gain pond (7) arranged in parallel; The coordinated connection component connects the end of the upstream ecological storage and circulation unit with the beginning of the downstream ecological purification unit through the culvert (2), and a pump station (8) is set at the end of the downstream ecological purification unit to regulate the water level.

2. The artificial wetland purification system according to claim 1, characterized in that: The layout angle of the spur dike (3) is 85°-95°, and an array of ecological floating islands (10) is arranged on the water-facing side of the spur dike (3), and the array of ecological floating islands (10) is planted with plants that remove nitrogen and phosphorus.

3. The artificial wetland purification system according to claim 1 or 2, characterized in that: The dead water area of ​​the regulating reservoir (1) is provided with a solar aeration system (9), and the aeration intensity of the solar aeration system (9) is dynamically adjusted based on feedback from a dissolved oxygen sensor.

4. The artificial wetland purification system according to claim 1, characterized in that: The slope ratio of the ecological island (5) is 1:8–1:12, the top height is 1m above the normal water level, and berry shrubs are planted on the surface.

5. The artificial wetland purification system according to claim 4, characterized in that: The berry shrubs include paper mulberry and pyracantha.

6. The artificial wetland purification system according to claim 1, characterized in that: The ecological purification filter bed (6) includes: a shallow water area with a water depth of 0.5-0.7m, in which an emergent plant belt is arranged, including a composite rhizosphere oxidation community of reeds and cattails; a deep water area with a water depth of 0.7-1.0m, in which a submerged-floating leaf plant cooperative belt is arranged, including a combination of Vallisneria and water lilies.

7. The artificial wetland purification system according to claim 1, characterized in that: The ecological gain pond (7) includes: planting Vallisneria and Water Shield in the deep water area; mixed sowing of Water Chestnut and Wild Rice in the shallow water area; and constructing a three-level nutrient cascade system consisting of plankton, fish, shrimp, shellfish, and filter-feeding fish in the ecological gain pond (7).

8. The artificial wetland purification system according to claim 1, characterized in that: The culvert (2) is equipped with a water level sensor and an automatic opening and closing device, which dynamically adjusts the water level difference according to the upstream water flow and the downstream purification demand.

9. An artificial wetland purification method, implemented based on the artificial wetland purification system according to any one of claims 1 to 8, characterized in that: Including steps: S1. Extend the water flow path by more than 30% by staggering the spur dikes (3) at 85°-95°; S2. Construct a three-level trophic cascade system in the ecological gain pond (7) with a stocking density of ≥ 5 per m 2 Filter-feeding shellfish and density ≤ 0.5 kg / m 3 filter-feeding fish; S3. Dynamically adjust the solar aeration intensity based on dissolved oxygen data and control the discharge volume of the pump station (8) through water level sensor feedback.

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