Fabricated composite constructed wetland system and method

Abstract

The invention discloses an assembly type composite artificial wetland system and method in the technical field of water treatment. The assembly type composite artificial wetland system comprises a main body frame, a subsurface flow wetland module, an upstream flow deep bed composite biological filter and an integrated process intelligent water distribution system, the main body frame comprises a supporting structure, a grating and a bottom supporting structure, and the grating divides the interior of the main body frame into an upper layer and a lower layer; the subsurface flow wetland module and the upstream flow deep bed composite biological filter are respectively arranged on the upper layer and the lower layer of the main body frame; the upstream deep-bed composite biological filter forms a multi-stage hierarchical structure along the water inlet direction; the integrated process intelligent water distribution system is located in the main body frame; the main body frame adopts a structural ecological design, and compared with a traditional concrete / reinforced concrete pool body structure, the energy consumption in the building construction process is lower; the treatment system adopts novel environment-friendly functional materials, and is suitable for ecological restoration of river / landscape water, upgrading and recycling of municipal tail water, recycling of aquaculture wastewater and treatment of agricultural non-point source pollution.

Description

Technical Field

[0001] This invention relates to a prefabricated composite artificial wetland system and method, belonging to the field of water treatment technology. Background Technology

[0002] With the acceleration of urbanization and the continuous increase in the intensity of industrial and agricultural activities, there is a widespread problem of organic pollutants, nitrogen and phosphorus nutrients and heavy metal accumulation in rivers, lakes and landscape water bodies. This can easily lead to environmental problems such as eutrophication and black and odorous water bodies, which not only affect the stability of the ecosystem, but also have an adverse impact on the living environment of residents and water resource security.

[0003] Constructed wetland technology is a water treatment technology that applies ecological engineering. Compared with traditional wastewater treatment technologies, it has the following advantages: it enhances the natural restoration process, resulting in less environmental disturbance; it can synergistically remove multiple pollutants such as suspended particulate matter, easily biodegradable organic pollutants, and pathogens; and its energy consumption is lower than that of centralized wastewater treatment systems. It has been widely used in the field of water treatment technology in recent decades. Traditional constructed wetland technologies include single-flow constructed wetland technologies and combined constructed wetland technologies. Single-flow constructed wetlands use single structures such as horizontal subsurface flow wetlands, vertical subsurface flow wetlands, or surface flow wetlands, which are characterized by simple construction and low construction costs. However, they have drawbacks such as large footprint, low pollution removal efficiency, and poor phosphorus / nitrogen removal capabilities. Furthermore, the system's adjustability and resistance to shock loads are weak, making it unsuitable for high-standard treatment of complex water bodies. Combined constructed wetlands typically employ a combination of vertical flow + horizontal flow, subsurface flow + surface flow, or wetland + biofilter series / parallel configurations. This enables deep and synergistic removal of pollutants, saving floor space compared to single-flow constructed wetlands. It also enhances system adjustability and resistance to shock loads, making it suitable for complex, fluctuating, and demanding deep treatment projects. Existing combined deep-bed (over 2 meters) constructed wetland systems generally use concrete / reinforced concrete tanks, which have the following drawbacks: long construction period, high construction cost, high energy consumption; multiple units operate independently, resulting in poor coordination and complex operation and maintenance, thus requiring high investment costs for construction and operation management. Furthermore, both single-flow and combined constructed wetland technologies suffer from low total nitrogen removal efficiency, large floor space requirements, unstable effluent, and short service life.

[0004] With socio-economic development, water pollution problems have become more complex and severe. The ecological degradation of rivers and lakes caused by nitrogen, phosphorus, and persistent organic pollutants is frequent, placing higher demands on water treatment technologies for the ecological restoration of polluted water bodies. Traditional constructed wetland technologies are no longer sufficient to meet the needs of water body ecological restoration. Composite constructed wetlands, through integrated design, enable multiple purification processes to work synergistically within a single structure or integrated module, achieving the coupling of multiple purification mechanisms compared to traditional constructed wetland technologies. Currently, composite constructed wetland technologies have been proven to have good water purification effects, as listed below: Chinese invention patent CN117228851A discloses a multi-stage composite artificial wetland system for purifying watershed water. The system consists of three-stage ecological ponds connected in series, which can improve the system's sedimentation rate, purification efficiency, and flood peak retention capacity. However, the multi-stage treatment units in this invention are connected in series, which has the disadvantages of large land area and weak anti-clogging ability, and is not suitable for urban municipal sewage treatment projects with scarce land resources.

[0005] Chinese invention patent CN 116375208 A discloses a self-trophic denitrification constructed wetland system. Through a trapezoidal arrangement of filtration zones, a first constructed wetland zone, and a second constructed wetland zone from high to low, it addresses the problems of insufficient carbon source and low nitrogen removal efficiency in traditional constructed wetland systems for the treatment of small rural water bodies. However, this system lacks a pre-ammonia oxidation unit, thus limiting its total nitrogen removal capacity. Furthermore, the system does not remove organic pollutants, total phosphorus, heavy metals, or other pollutants, resulting in low purification efficiency and requiring combination with other pollutant removal processes, thus restricting its application scope.

[0006] Chinese invention patent CN113788546A discloses a composite constructed wetland with deep denitrification function. It consists of an internal deep denitrification filter and an external constructed wetland forming a concentric hollow cylindrical structure. This structure offers advantages such as water quality activation, wetland clogging relief, high integration, and convenient management, enabling the organic integration of constructed wetlands with urban wastewater treatment plants. However, the main structure of this invention is concrete masonry, resulting in high construction costs and long construction periods. Furthermore, the low level of system automation leads to a heavy reliance on manual labor for operation and maintenance, exhibiting poor adjustability of operating parameters and weak self-maintenance capabilities.

[0007] Chinese invention patent CN120964993A discloses a composite artificial wetland system that uses surface flow wetland, horizontal subsurface flow wetland unit, "gravel interbed" technology and plant ecological buffer zone unit to circulate and treat sewage, solving the problems of single function and low treatment efficiency of traditional artificial wetlands. However, the wetland is surrounded by brick retaining walls to form a pool, which has a large area, long construction period and high construction cost.

[0008] Chinese invention patent CN 110294531B ​​discloses a water treatment system and method based on an ecological core wetland, comprising an upper subsurface flow wetland layer and a lower biofilter layer. This system combines subsurface flow wetland and biofilter water treatment processes, removing pollutants from the water through the interception / sedimentation / adsorption of the upper subsurface flow wetland packing layer, microbial action, plant root absorption, and the microbial action of the lower biofilter layer. However, this system uses a concrete integrated structure design, which has disadvantages such as long construction period, high cost, and high energy consumption. Furthermore, once the project is completed, it is difficult to expand or modify, and cannot flexibly respond to scenarios where water treatment targets frequently change, such as surface water, aquaculture wastewater, and agricultural non-point source pollution. In addition, the system lacks an intelligent water distribution system, making it difficult to achieve real-time control of water distribution and distribution functions in various process pipelines. The system has a low level of intelligence, relies on manual operation and maintenance, and has high costs.

[0009] Furthermore, existing constructed wetland water purification systems mostly adopt an integrated structural layout with a low degree of modularization, making on-site construction and subsequent expansion and renovation difficult. Natural water bodies exhibit significant seasonal and regional variations in water quality, and when the treatment scale or objectives change, extensive dismantling and modification of the original structure are often required. This places higher demands on the ease of operation and maintenance and the scalability of functions of constructed wetland systems, making it difficult for existing constructed wetland water purification systems to meet the requirements of actual application scenarios.

[0010] Although Chinese invention patent CN114835259A provides a prefabricated wetland device, which features convenient installation, saves construction time, and is easy to operate and maintain, its wetland unit modules purify water using conventional filler and plant units. Physical adsorption, biochemical reactions, and microbial activity occur in the same area, essentially remaining a traditional single-flow constructed wetland technology. This technology suffers from strong environmental constraints, low pollution load, and low purification efficiency. In particular, it lacks a highly efficient composite process for nitrogen and phosphorus removal, making it difficult to guarantee water purification results. Furthermore, the independent operation of each functional unit, coupled with the inability to control them in real time, makes it difficult to ensure effectiveness in practical applications with significant fluctuations in water quality and quantity, and where high requirements for total nitrogen and total phosphorus levels exist. Summary of the Invention

[0011] This invention provides a prefabricated composite artificial wetland system and method, which solves the problems of long construction period, high construction cost, large land area, low purification efficiency, poor adjustability of operating parameters, weak self-maintenance capability and low degree of assembly in the treatment process of existing artificial wetland technologies.

[0012] Firstly, a prefabricated composite artificial wetland system and method are provided, including... The main frame, subsurface flow wetland module, upflow deep bed composite biological filter, and integrated intelligent water distribution system; The main frame includes a support structure, a grid, and a bottom support structure. The grid divides the interior of the main frame into upper and lower layers, and the bottom support structure is set as an inclined structure along the water inlet direction. The subsurface flow wetland module and the upflow deep bed composite biological filter are respectively set in the upper and lower layers of the main frame, and are stacked longitudinally and separated by the grid. The upward flow deep bed composite biological filter forms a multi-level hierarchical structure along the water inlet direction; The integrated process intelligent water distribution system is located inside the main frame and includes an inlet water distribution system, a graded water distribution system in the subsurface flow wetland module, and an integrated process pipeline system in the upflow deep bed composite biological filter.

[0013] Furthermore, the support structure, from the inside out, includes plastic-plastic board, a seepage-proof layer, and plastic-steel sheet piles; The surface of the plastic-wood board is provided with square tube steel piles; The grid is made of plastic or fiberglass and is anchored to the support structure on all four sides. The bottom support structure is a plastic base plate, a fiberglass base plate, or a cast-in-place base plate, with a seepage-proof layer on its outer side, and the seepage-proof layer is welded to the seepage-proof layer in the support structure. A dense sand cushion layer is laid below the bottom support structure; The bottom support structure is set at an inclination angle of 5 to 10° along the water flow direction.

[0014] Furthermore, the subsurface flow wetland module is filled with an environmentally friendly functional material—modified biochar phosphorus removal filler. The thickness of the filler layer is 40–80 cm; The packing layer consists of multiple layers of modified biochar phosphorus removal packing, with the particle size of each layer gradually decreasing from bottom to top.

[0015] Furthermore, the upward flow deep bed composite biological filter uses multiple partition walls to divide the filter into multiple treatment units.

[0016] Furthermore, the height of the upward flow deep bed composite biological filter is 3-4m, and the water depth inside the filter is 2-3m. The upward-flowing deep-bed composite biological filter is filled with bio-enhancing biochar-based filler as a slow-release carbon source and microbial growth carrier, and flows sequentially through multiple treatment units along the inlet direction. Each treatment unit includes at least one aerobic tank and 2-3 denitrification tanks, or 3-4 simultaneous nitrification and denitrification units.

[0017] Furthermore, the water inlet and distribution system is located at the water inlet end of the prefabricated composite artificial wetland system and is connected to the water inlet pipelines of the subsurface flow wetland module and the upflow deep bed composite biological filter, respectively.

[0018] Furthermore, the graded water distribution system is set inside the subsurface flow wetland module and above the upflow deep bed composite biological filter, including a bottom support layer, a bottom water distribution layer, a water distribution power device, and a top water collection layer; The bottom water distribution layer is provided with a graded water distribution pipe, which includes a main pipe and multiple branch pipes; The main pipe is arranged along the length of the wetland unit, and multiple branch pipes are connected to the main pipe and distributed laterally. The bottom support layer is composed of multiple layers of gravel, with the gravel particle size gradually decreasing from bottom to top. The top water collection layer includes a perforated water collection pipe and a water level regulator, and is connected to the inlet pipe of the upward flow deep bed composite biological filter through a pipeline. The water distribution power unit includes a booster pump and a pulse generator.

[0019] Furthermore, the integrated process piping system includes an inlet pipe, a dosing pipe, an aeration pipe, and a sludge discharge pipe; The inlet pipeline and the dosing pipeline are located above the upward flow deep bed composite biological filter. The dosing lines for each treatment unit are connected to the inlet water line; The aeration pipeline and sludge discharge pipeline are located at the bottom of the upward flow deep bed composite biological filter and above the bottom support structure.

[0020] Furthermore, the upflow deep bed composite biological filter includes 3 to 4 stages of biological filters; Flow pipes are installed at the inlet of each stage of the biological filter. One end of the overflow pipe of the first-stage biological filter is connected to the inlet pipe, and the other end is connected to the bottom of the first-stage biological filter. One end of the flow pipe of the second-stage biological filter is connected to the upper end of the first-stage biological filter, and the other end is connected to the bottom of the second-stage biological filter. Both the third-stage and fourth-stage biological filters are equipped with flow pipes. The main frame has an outlet on one side of the final stage biological filter.

[0021] Secondly, a water purification method for a prefabricated composite constructed wetland system is provided, applied to the prefabricated composite constructed wetland system described in the first aspect, the method comprising: The wastewater to be treated is pumped into the constructed wetland system through the inlet water distribution system, which divides the wastewater into two streams. The first stream of wastewater enters the subsurface flow wetland module through the graded water distribution system of the upper subsurface flow wetland module, and then enters the inlet pipeline of the lower upflow deep bed composite biological filter through the top water collection layer of the subsurface flow wetland module. The second wastewater stream directly enters the inlet pipe of the lower-level upward flow deep-bed composite biological filter. The two streams of sewage converge in the upflow deep bed composite biological filter and then flow through each level of biological filter in sequence, with the water flow direction in each level of biological filter being from bottom to top. The treated water flows out through the final biological filter and is discharged through the outlet.

[0022] The main frame of this invention adopts an ecological structural design with a high degree of prefabrication, which facilitates construction and expansion. Compared with traditional concrete / steel-concrete pool structures, it has lower energy consumption during construction, and its construction cost and construction period are reduced by 45% and 55% respectively. It is suitable for ecological restoration of rivers / landscape water bodies, upgrading of municipal tailwater, reuse of aquaculture wastewater, and treatment of agricultural non-point source pollution.

[0023] This invention creates a layered synergistic structure by dividing the main frame into upper and lower layers with a grid. The upper layer is a subsurface flow wetland process, and the lower layer is an upward flow deep bed composite biological filter process, which are longitudinally superimposed in space to form a layered synergistic structure. This structure can extend the hydraulic retention time and improve the water purification effect. Compared with traditional surface flow constructed wetland technology, the project area is reduced by 90% and the water purification effect is improved by 7.5 times under the condition of treating the same water quality and quantity.

[0024] This invention, through an integrated intelligent water distribution system, enables precise control of the influent volume of the constructed wetland system and the diversion ratio between the upper subsurface flow wetland module and the lower upflow deep bed composite biological filter, based on water quality and quantity targets. Simultaneously, it provides multi-functional integrated control over the water distribution to the upper subsurface flow wetland module and the influent, chemical dosing, aeration, and sludge removal processes of the lower upflow deep bed composite biological filter. This effectively regulates the treated water volume of the prefabricated composite constructed wetland system, the influent ratio between the subsurface flow wetland and the upflow deep bed composite biological filter processes, optimizes the hydraulic path of the subsurface flow wetland module, and intelligently controls the influent / chemical dosing / aeration / sludge removal processes of the upflow deep bed composite biological filter. This improves the adjustability of operating parameters and enhances the anti-clogging and self-maintenance capabilities of the constructed wetland system.

[0025] The subsurface flow wetland module of this invention uses environmentally friendly functional material—modified biochar phosphorus removal filler—combined with nano-metal technology, giving the material higher adsorption activity. Compared with traditional ceramsite filler, the adsorption efficiency for organic matter, TP, and heavy metals is increased by 15 times, 10 times, and 5 times, respectively. The upflow deep bed composite biological filter couples bio-enhanced biochar-based slow-release carbon source material with fixed bed synchronous nitrification and denitrification process, improving biofilm contact efficiency and eliminating the dependence on carbon source in traditional anaerobic denitrification process. Actual operation data from its application in urban municipal wastewater upgrading projects show that in a 10,000 t / d scale municipal wastewater treatment project, the annual carbon source value can reach 600,000 yuan. Attached Figure Description

[0026] Figure 1 The diagram shown is a schematic diagram of an integrated intelligent water distribution system provided in an embodiment of the present invention. Figure 2 The diagram shown is a flowchart of the integrated intelligent water distribution system provided in an embodiment of the present invention. Figure 3 The figure shown is an overall schematic diagram of the prefabricated composite artificial wetland system provided in an embodiment of the present invention; Figure 4 The diagram shown is a schematic representation of the main frame and grid structure of the prefabricated composite artificial wetland system provided in an embodiment of the present invention. Figure 5 The image shown is a top view of the prefabricated composite artificial wetland system provided in an embodiment of the present invention. Attached Figure Description

[0027] 1. Main frame; 2. Subsurface flow wetland module; 3. Upflow deep bed composite biological filter; 4. Integrated intelligent water distribution system; 5. Graded water distribution system; 6. Integrated process piping system; 7. Upflow deep bed composite biological filter inlet pipe; 8. Flow pipe; 9. Outlet; 11. Support structure; 12. Grille; 13. Bottom support structure; 31. Partition wall; 41. Inlet water distribution system; 51. Bottom support layer; 52. Bottom water distribution layer; 54. Top water collection layer; 61. Chemical dosing pipeline; 62. Aeration pipeline; 63. Sludge discharge pipeline; 111. Plastic-plastic board; 112. Impermeable layer; 113. Plastic-steel sheet pile; 114. Square tube steel pile. Detailed Implementation

[0028] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations thereof. In the absence of conflict, the embodiments and technical features in the embodiments can be combined with each other.

[0029] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0030] In one specific implementation, such as Figure 3 , Figure 4 and Figure 5 As shown, a prefabricated composite artificial wetland system is provided, including a main frame 1, a subsurface flow wetland module 2, an upflow deep bed composite biological filter 3, and an integrated intelligent water distribution system 4.

[0031] The main frame 1 includes a support structure 11, a grid 12, and a bottom support structure 13. The grid 12 is disposed inside the main frame 1, dividing the main frame 1 into upper and lower layers. The bottom support structure 13 is disposed at the bottom of the main frame 1 and is inclined along the water inlet direction.

[0032] The subsurface flow wetland module 2 is positioned above the grid 12, and the upward flow deep bed composite biological filter 3 is positioned below the grid 12. The subsurface flow wetland module 2 and the upward flow deep bed composite biological filter 3 are stacked vertically and separated by the grid 12, thus forming the core unit for water purification in this prefabricated composite artificial wetland system.

[0033] The support structure 11 comprises, from the inside out, a plastic-plastic board 111, a seepage-proof layer 112, and plastic-steel sheet piles 113. Square tube steel piles 114 are installed on the surface of the plastic-plastic board 111 for lateral support. The grid 12 is connected to the support structure 11 by anchoring. The bottom support structure 13 is composed of a plastic base plate, a fiberglass base plate, or a cast-in-place base plate, with a seepage-proof layer 112 installed at its outer end and connected to the seepage-proof layer 112 on the support structure 11. The bottom support structure 13 is inclined at 5° to 10° along the water flow direction.

[0034] The subsurface flow wetland module 2 is filled with modified biochar phosphorus removal filler, with a filler layer thickness of 40-80cm, and is laid in a graded manner with the particle size gradually decreasing from bottom to top.

[0035] like Figure 1As shown, the subsurface flow wetland module 2 is equipped with a graded water distribution system 5, which includes a bottom support layer 51, a bottom water distribution layer 52, a water distribution power unit, and a top water collection layer 54. The bottom water distribution layer 52 contains graded water distribution pipes for uniform water distribution; the bottom support layer 51 is composed of layered gravel, with the particle size gradually decreasing from bottom to top; the top water collection layer 54 includes perforated water collection pipes for collecting the treated water from the subsurface flow wetland module 2 and introducing it into the inlet pipe 7 of the upward flow deep bed composite biological filter 3. The water distribution power unit includes a lift pump and a pulse generator for pumping the water into the water distribution network of the bottom water distribution layer 52.

[0036] The integrated process intelligent water distribution system 4 includes an inlet water distribution system 41, a graded water distribution system 5, and an integrated process pipeline system 6. The inlet water distribution system 41 is located at the inlet end of the wetland system and is used to introduce the water to be treated. The graded water distribution system 5 in the subsurface flow wetland module 2 is used to evenly distribute the water in the packing layer and intelligently regulate the water flow. The integrated process pipeline system 6 in the upflow deep bed composite biological filter 3 includes a chemical dosing pipeline 61, an aeration pipeline 62, and a sludge discharge pipeline 63, which are used to connect the biological filters at each level and realize the transportation of water at each level.

[0037] The upward-flowing deep-bed composite biological filter 3 forms a multi-stage biological filter along the water inlet direction. Each stage of the biological filter is connected by a flow pipe 8, allowing the water to flow sequentially. The first-stage biological filter is connected to the top water collection layer 54 through the water inlet pipe 7, allowing the water treated by the subsurface flow wetland module 2 to enter the biological filter 3.

[0038] Aeration pipes 62 are installed in each stage of the biological filter to supply oxygen to the microorganisms and to backwash the internal packing layer; sludge discharge pipes 63 are installed at the bottom to discharge sediment. Chemical dosing pipes 61 are used to add microbial agents, carbon sources or other regulatory substances.

[0039] The effluent from the entire system is discharged through outlet 9 and can be used for reuse in rivers, landscape water bodies, municipal wastewater, aquaculture, or agricultural irrigation.

[0040] During operation, the water to be treated first enters the system through the inlet distribution system 41, and after being treated by the subsurface flow wetland module 2, it enters the upward flow deep bed composite biological filter 3 through the top water collection layer 54 and the inlet pipeline 7 of the upward flow deep bed composite biological filter. The water undergoes further treatment in the multi-stage biological filter by passing through each stage of the biological filter in sequence, and is finally discharged through the outlet 9.

[0041] It is worth mentioning that the main frame of the prefabricated composite constructed wetland system adopts an ecological and prefabricated design to replace the traditional concrete / reinforced concrete structure. The vertical support structure of the main frame uses a combination of plastic wood panels, an impermeable layer, and plastic steel sheet piles as interlayers, and square tube steel piles as the material for lateral support instead of traditional concrete pool walls. The bottom support structure of the main frame consists of a cast-in-place base slab or a high-strength plastic base slab laid on a dense sand cushion layer, and an impermeable layer laid on the cast-in-place base slab or high-strength plastic base slab. The interior of the prefabricated composite constructed wetland system is divided into upper and lower layers by a grid: the upper layer is equipped with subsurface flow wetland modules, which are filled with eco-friendly and environmentally friendly functional materials—modified biochar phosphorus removal fillers; the lower layer is equipped with an upward flow deep bed composite biological filter, which is filled with bio-enhanced biochar-based slow-release carbon source fillers, forming multi-stage treatment units along the water inlet direction; and the bottom is equipped with a bottom support structure arranged inclined along the water inlet direction.

[0042] Specifically, a prefabricated composite artificial wetland system also includes an integrated intelligent water distribution system, which consists of an inlet water distribution system, a subsurface flow wetland gradation water distribution system, and a biological filter integrated process pipeline system. The prefabricated composite artificial wetland system described in this invention features a structurally ecological design for its main frame, a high degree of prefabrication, and ease of construction and expansion. Compared to traditional concrete / steel-concrete pool structures, it consumes less energy during construction, reducing construction costs and time by 45% and 55%, respectively. It is suitable for ecological restoration of rivers / landscape water bodies, upgrading municipal wastewater, recycling aquaculture wastewater, and treating agricultural non-point source pollution. By vertically superimposing subsurface flow wetland technology with upflow deep-bed composite biological filter technology, the synergistic effect of the subsurface flow wetland module's packing adsorption and the upflow deep-bed composite biological filter's multi-stage biological treatment extends hydraulic retention time and improves water purification efficiency. Compared to traditional surface flow artificial wetland technology, under the condition of treating the same water quality and quantity, the project's land area is reduced by 90%, and the water purification effect is improved by 7.5 times.

[0043] like Figure 2 As shown, this embodiment also provides a method for constructing a prefabricated composite artificial wetland, applied to the above-mentioned prefabricated composite artificial wetland system. The method includes: The wastewater to be treated is pumped into the constructed wetland system through the inlet water distribution system 41, which divides the wastewater into two streams. The first stream of wastewater enters the subsurface flow wetland module 2 through the graded water distribution system 5 and then enters the inlet pipe 7 through the top water collection layer 54. The second wastewater stream enters the inlet pipe 7 of the upward flow deep bed composite biological filter; After the two streams of sewage converge in the upflow deep bed composite biological filter 3, they flow sequentially through each level of biological filter, with the water flow direction in each level of biological filter being from bottom to top. The treated water flows out through the final biological filter and is discharged through outlet 9.

[0044] The description herein is provided to enable those skilled in the art to implement or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the scope of the disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but should be given the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A prefabricated composite artificial wetland system, characterized in that: It includes the main frame (1), the subsurface flow wetland module (2), the upflow deep bed composite biological filter (3), and the integrated process intelligent water distribution system (4). The main frame (1) includes a support structure (11), a grid (12) and a bottom support structure (13). The grid (12) divides the interior of the main frame (1) into upper and lower layers. The bottom support structure (13) is set as an inclined structure along the water inlet direction. The subsurface flow wetland module (2) and the upflow deep bed composite biological filter (3) are respectively set in the upper and lower layers of the main frame (1), and are stacked longitudinally and separated by the grid (12); The upward flow deep bed composite biological filter (3) forms a multi-level hierarchical structure along the water inlet direction; The integrated process intelligent water distribution system (4) is located inside the main frame (1) and includes an inlet water distribution system (41), a graded water distribution system (5) in the subsurface flow wetland module (2), and an integrated process pipeline system (6) in the upflow deep bed composite biological filter (3) for microbial agent replenishment, carbon source replenishment, aeration and backwashing, and sludge discharge system.

2. The prefabricated composite artificial wetland system according to claim 1, characterized in that, The support structure (11) includes, from the inside out, a plastic board (111), a seepage-proof layer (112), and a plastic steel sheet pile (113). The surface of the plastic board (111) is provided with square tube steel piles (114). The grille (12) is a fiberglass mesh plate, which is anchored to the support structure (11) on all four sides; The bottom support structure (13) is a plastic base plate, a fiberglass base plate or a cast base plate, with an anti-seepage layer on its outer side, and the anti-seepage layer is welded to the anti-seepage layer in the support structure (11); A dense sand cushion layer is provided below the bottom support structure (13) and its outer impermeable layer; The bottom support structure (13) is set at an inclination angle of 5 to 10° along the water flow direction, with the lower end located at the outlet end of the prefabricated composite artificial wetland system, so as to facilitate the prefabricated composite artificial wetland system to realize the functions of water collection and return.

3. The prefabricated composite artificial wetland system according to claim 1, characterized in that, The subsurface wetland module (2) is filled with environmentally friendly functional material—modified biochar phosphorus removal filler; The thickness of the filler layer is 40–80 cm; The packing layer consists of multiple layers of modified biochar phosphorus removal packing, with the particle size of each layer gradually decreasing from bottom to top.

4. The prefabricated composite artificial wetland system according to claim 1, characterized in that, The height of the upflow deep bed composite biological filter (3) is 3-4m, the water depth in the tank is 2-3m, and the filter is divided into multiple treatment units by multiple partition walls (31). The internal filling of the upflow deep bed composite biological filter (3) is a biologically enhanced biomass carbon-based filler as a slow-release carbon source and microbial growth carrier. Wastewater flows through multiple treatment units in sequence along the inlet direction. A multi-stage treatment unit includes at least one aerobic tank and 2-3 denitrification tanks, or 3-4 simultaneous nitrification and denitrification tanks.

5. A prefabricated composite artificial wetland system according to claim 1, characterized in that, The water inlet and distribution system (41) is located at the water inlet end of the prefabricated composite artificial wetland system and is connected to the water inlet pipelines of the subsurface flow wetland module (2) and the upward flow deep bed composite biological filter (3), respectively.

6. The prefabricated composite artificial wetland system according to claim 1, characterized in that, The graded water distribution system (5) is set inside the subsurface flow wetland module (2) and above the upflow deep bed composite biological filter (3), including a bottom support layer (51), a bottom water distribution layer (52), a water distribution power device and a top water collection layer (54). The bottom water distribution layer (52) is provided with a graded water distribution pipe, which includes a main pipe and multiple branch pipes; The main pipe is arranged along the length of the wetland unit, and multiple branch pipes are connected to the main pipe and distributed laterally. The bottom support layer (51) is composed of multiple layers of gravel, with the gravel particle size gradually decreasing from bottom to top; The top water collection layer (54) includes a perforated water collection pipe and a water level regulator, and is connected to the inlet pipe (7) of the upward flow deep bed composite biological filter through a pipeline; The water distribution power unit includes a booster pump and a pulse generator to achieve continuous or intermittent water distribution.

7. A prefabricated composite artificial wetland system according to claim 1, characterized in that, The integrated process piping system (6) includes an inlet pipe (7), a dosing pipe (61), an aeration pipe (62), and a sludge discharge pipe (63). The inlet pipe (7) and the dosing pipe (61) are located above the upward flow deep bed composite biological filter (3); The dosing pipeline (61) of each treatment unit is connected to the inlet water pipeline (7); The aeration pipeline (62) and sludge discharge pipeline (63) are located at the bottom of the upward flow deep bed composite biological filter (3) and above the bottom support structure (13).

8. A prefabricated composite artificial wetland system according to claim 1, characterized in that, The upflow deep bed composite biological filter (3) includes 3 to 4 stages of biological filters; The inlet of each level of biological filter is equipped with a flow pipe (8); One end of the overflow pipe (8) of the first-stage biological filter is connected to the inlet pipe (7), and the other end is connected to the bottom of the first-stage biological filter. One end of the overflow pipe (8) of the second-stage biological filter is connected to the upper end of the first-stage biological filter, and the other end is connected to the bottom of the second-stage biological filter. Both the third-stage and fourth-stage biological filters are equipped with flow pipes (8); The main frame (1) has an outlet (9) on one side of the final biological filter.

9. A method for constructing prefabricated composite artificial wetlands, characterized in that, The method, applied to the prefabricated composite artificial wetland system according to any one of claims 1-8, comprises: The wastewater to be treated is pumped into the constructed wetland system through the water inlet distribution system (41), and the water inlet distribution system (41) divides the wastewater into two streams; The first stream of wastewater enters the subsurface flow wetland module (2) through the graded water distribution system (5) of the subsurface flow wetland module (2), and then enters the inlet pipeline (7) of the upward flow deep bed composite biological filter through the top water collection layer (54). The second wastewater stream directly enters the inlet pipe of the upward flow deep bed composite biological filter (7). After the two streams of sewage converge in the upflow deep bed composite biological filter (3), they flow through each level of biological filter in sequence. The water flow direction of each level of biological filter is from bottom to top. The treated water flows out through the final biological filter and is discharged through the outlet (9).

Images