Permeable flexible boundary constructed wetland system

Abstract

The application discloses a kind of permeable flexible boundary constructed wetland system, it is related to sewage treatment system technical field, including constructed wetland, permeable boundary and soil package zone.The water boundary of traditional constructed wetland is changed from impermeable boundary to permeable boundary, after wastewater is treated by constructed wetland, part enters permeable boundary and contacts with the filler inside, and enhanced phosphorus removal is carried out.Then, it flows out from permeable boundary and enters soil package zone, based on the denitrification capacity of soil package zone, the effect of enhanced denitrification is strengthened;Finally, the effluent after further purification by soil package zone is discharged into natural system, to realize the flexible integration of constructed wetland and natural system.Another part of effluent enters the water collecting well through drain pipe, and then is discharged through overflow hole on the water collecting well.The flexible integration of constructed wetland ecological restoration system and natural system is realized, and the enhanced reduction of nitrogen and phosphorus pollution is synchronized, and the situation of underground runoff channel fragmentation and biological diversity fragmentation caused by restoration process is avoided.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment system technology, and in particular to a permeable flexible boundary constructed wetland system. Background Technology

[0002] In recent years, the demand for ecological restoration of natural water bodies has been increasing, becoming a hot topic of common concern in ecology, environmental science, and earth science. Constructed wetlands, as an important ecological restoration technology, have been widely used for the treatment and interception of urban landscape water bodies, rural domestic sewage, agricultural runoff, and non-point source pollution. However, the boundaries of currently constructed constructed wetlands are all impermeable, preventing the exchange and connection of water or other ecological substances within the constructed wetland with natural systems. This is particularly true for constructed wetlands widely used in the construction of sponge cities, where the impermeable walls block normal underground runoff channels, which is inconsistent with the concepts of sustainable development and natural system restoration.

[0003] Therefore, how to develop a system that can achieve flexible integration of constructed wetlands and nature, so that it can interact and integrate with natural systems while using constructed wetland technology for wastewater treatment, in order to improve the sustainability and ecological efficiency of constructed wetlands and realize the concept of ecological restoration of simulated natural systems, is an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a permeable flexible boundary artificial wetland that can flexibly integrate artificial wetlands and natural systems, in order to solve the problems existing in the prior art. It transforms the effluent boundary of the artificial wetland from an impermeable boundary to a permeable boundary, allowing sewage to flow through the boundary by gravity, thereby achieving a flexible integration of artificial wetlands and natural systems.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides a permeable flexible boundary constructed wetland system, comprising a constructed wetland, a permeable boundary, and a soil vadose zone; one end of the constructed wetland is the water inlet boundary, the two sides of the constructed wetland are the left boundary and the right boundary, respectively, and the bottom of the constructed wetland is the bottom boundary; the water inlet boundary, the left boundary, the right boundary, and the bottom boundary are all impermeable boundaries; the other end of the constructed wetland communicates with the soil vadose zone through the permeable boundary.

[0007] Optionally, the permeable boundary adopts a three-section structure from left to right in the horizontal direction and from top to bottom in the vertical direction, forming nine modules. The nine modules are the upper left section, the upper middle section, the upper right section, the middle left section, the middle middle section, the middle right section, the lower left section, the lower middle section, and the lower right section of the permeable boundary module. Each module is filled with a mixture of phosphorus removal material and clay in different proportions to form different permeability coefficients.

[0008] Optionally, the permeability coefficient of the upper left section of the permeable boundary module is 15.0-20.0 m / d;

[0009] The permeability coefficient of the upper middle section of the permeable boundary module is 10.0-15.0 m / d;

[0010] The permeability coefficient of the upper right section of the permeable boundary module is 5-10.0 m / d;

[0011] The permeability coefficient of the middle left section of the permeable boundary module is 10.0-15.0 m / d;

[0012] The permeability coefficient of the middle section of the permeable boundary module is 5.0-10.0 m / d;

[0013] The permeability coefficient of the right section of the permeable boundary module is 2.0-5.0 m / d;

[0014] The permeability coefficient of the lower left section of the permeable boundary module is 5.0-10.0 m / d;

[0015] The permeability coefficient of the lower middle section of the permeable boundary module is 2.0-5.0 m / d;

[0016] The permeability coefficient of the lower right section of the permeable boundary module is 0.5-2.0 m / d.

[0017] Optionally, the permeability coefficient of the upper left section of the permeable boundary module is greater than that of the upper middle section of the permeable boundary module, which is greater than that of the middle left section of the permeable boundary module; the permeability coefficient of the middle left section of the permeable boundary module is greater than that of the middle middle section of the permeable boundary module, which is greater than that of the middle right section of the permeable boundary module; and the permeability coefficient of the lower left section of the permeable boundary module is greater than that of the lower middle section of the permeable boundary module, which is greater than that of the lower right section of the permeable boundary module.

[0018] Optionally, the permeable boundary has a trapezoidal structure, and the width of the permeable boundary gradually increases from the artificial wetland to the soil vadose zone.

[0019] Optionally, the angle between the left and right sides of the permeable boundary and the artificial wetland is 30°-50°.

[0020] Optionally, the aspect ratio of the main filler material area of ​​the constructed wetland is controlled to be below 3:1, and the filling height of the main filler material area of ​​the constructed wetland is in the range of 0.8-1.5m.

[0021] Optionally, the hydraulic retention time of wastewater in the constructed wetland is 1.0-1.3 days, and the hydraulic loading rate is 0.3-0.4 m³. 3 / (m 2 ·d).

[0022] The present invention achieves the following technical effects compared to the prior art:

[0023] The permeable flexible boundary constructed wetland system of this invention uses a permeable boundary at the outlet end. The permeable boundary adopts a modular structure, with each module filled with a mixture of phosphorus removal material and clay in different proportions to form different permeability coefficients. After treatment by the constructed wetland, a portion of the effluent slowly enters the permeable boundary, which can enhance phosphorus removal. Then, it flows out from the permeable boundary into the vadose zone of the soil, where the denitrification effect is enhanced based on the denitrification capacity of the vadose zone. Finally, the effluent, after further purification by the vadose zone, is discharged into the natural system, realizing the flexible integration of the constructed wetland and the natural system.

[0024] The permeable flexible boundary constructed wetland system of the invention couples the constructed wetland and the vadose zone of the soil through a permeable reactive boundary. After the wastewater is treated by the permeable boundary, it is further integrated and reacted with the natural system, realizing the flexible integration of the constructed wetland ecological restoration system with the natural system and the simultaneous enhancement and reduction of nitrogen and phosphorus pollution, while avoiding the disruption of underground runoff channels and the fragmentation of biodiversity caused by the restoration process. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A plan view of a permeable flexible boundary constructed wetland system;

[0027] Figure 2 This is a cross-sectional view of a permeable flexible boundary constructed wetland system.

[0028] Explanation of reference numerals in the attached diagram: 1. Constructed wetland; 2. Permeable boundary; 2-1. Upper left section of the permeable boundary module; 2-2. Upper middle section of the permeable boundary module; 2-3. Upper right section of the permeable boundary module; 2-4. Middle left section of the permeable boundary module; 2-5. Middle middle section of the permeable boundary module; 2-6. Middle right section of the permeable boundary module; 2-7. Lower left section of the permeable boundary module; 2-8. Lower middle section of the permeable boundary module; 2-9. 1. Lower right section of the permeable boundary module; 2-10. Angles between the left and right sides of the permeable boundary and the constructed wetland; 3. Soil vadose zone; 4. Inlet pipe; 5. Water distribution area; 6. Main filler area of ​​the constructed wetland; 7. Constructed wetland plants; 8. Constructed wetland outlet area; 9. Constructed wetland inlet boundary; 10. Left boundary of the constructed wetland; 11. Right boundary of the constructed wetland; 12. Bottom boundary of the constructed wetland; 13. Drainage pipe; 14. Collection well; 15. Overflow hole of the collection well. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The purpose of this invention is to provide a permeable flexible boundary constructed wetland system. This system couples the constructed wetland and the vadose zone of the soil through a permeable boundary, realizing the flexible integration of the constructed wetland ecological restoration system with the natural system and simultaneously enhancing and reducing nitrogen and phosphorus pollution, while avoiding the disruption of underground runoff channels and the fragmentation of biodiversity caused by the restoration process.

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] like Figure 1 and Figure 2As shown, this invention provides a permeable flexible boundary constructed wetland system, including a constructed wetland 1, a permeable boundary 2, and a soil vadose zone 3; one end of the constructed wetland 1 is the constructed wetland inlet boundary 9, the two sides of the constructed wetland 1 are the constructed wetland left boundary 10 and the constructed wetland right boundary 11, respectively, and the bottom of the constructed wetland 1 is the constructed wetland bottom boundary 12; the constructed wetland inlet boundary 9, the constructed wetland left boundary 10, the constructed wetland right boundary 11, and the constructed wetland bottom boundary 12 are all impermeable boundaries; the other end of the constructed wetland 1... The artificial wetland 1 is connected to the soil vadose zone 3 through the permeable boundary 2; a water distribution area 5 is set inside one end of the artificial wetland 1, and an inlet pipe 4 is set at the top of the water distribution area 5; an artificial wetland outlet area 8 is set at the other end of the artificial wetland 1, and a drainage pipe 13 is set at the bottom of the artificial wetland outlet area 8, which connects the artificial wetland outlet area 8 with the soil vadose zone 3; an artificial wetland main filler area 6 is set inside the artificial wetland 1 between the water distribution area 5 and the artificial wetland outlet area 8, and artificial wetland plants 7 are planted in the artificial wetland main filler area 6.

[0033] Among them, the permeable boundary 2 is to change the seepage-proof boundary of the conventional constructed wetland into a permeable boundary. The constructed wetland 1 and the soil vadose zone 3 are coupled through the permeable boundary 2, so that the effluent of the constructed wetland 1 is further flowed into the soil vadose zone 3 area after being deeply treated by the permeable boundary 2, forming a flexible integration between the constructed wetland and the natural system.

[0034] In practical applications, wastewater first enters the constructed wetland distribution area 5 through the inlet pipe 4. After being purified by the main material packing area 6 and the constructed wetland plants 7, the effluent passes through the constructed wetland effluent area 8. A portion slowly enters the permeable boundary 2, where it contacts the packing material for enhanced phosphorus removal. Then, it flows out of the permeable boundary 2 into the soil vadose zone 3, where its denitrification capacity is further enhanced. Finally, the effluent, further purified by the soil vadose zone 3, is discharged into the natural system, achieving a flexible integration of the constructed wetland 1 with the natural system. The remaining effluent, which cannot be absorbed by the soil vadose zone system 2, enters the collection well 14 through the drain pipe 13 and is then discharged through the overflow hole 15 on the collection well 14.

[0035] In practical applications, constructed wetland 1 is a horizontal subsurface flow constructed wetland. The bed contains the main filler material zone 6 and aquatic plants 7. The effluent boundary of constructed wetland 1 is a permeable boundary 2, while the left boundary 10, right boundary 11, and bottom boundary 12 are still impermeable boundaries. The aspect ratio of the main filler material zone 6 is controlled below 3:1, and the filling height of the main filler material zone 6 ranges from 0.8 to 1.5 m. The hydraulic retention time of wastewater in constructed wetland 1 is 1.0 to 1.3 days, and the hydraulic load is 0.3 to 0.4 m. 3 / (m 2 ·d).

[0036] In practical applications, the permeable boundary 2 is located at the outlet end of the constructed wetland 1. Specifically, the boundary 2 is an extension of the constructed wetland 1, and its shape is trapezoidal. The angle 2-10 between the left and right sides (waists) of the trapezoid and the constructed wetland is 30°-50°. A drainage pipe 13 is laid at the bottom of the permeable boundary 2 to discharge the overloaded water from the constructed wetland 1 into the collection well 14.

[0037] In practical applications, the permeable boundary 2 is a modular structure, employing a three-section structure both horizontally from left to right and vertically from top to bottom, forming nine modules. Each module is filled with a mixture of phosphorus removal material and clay in different proportions, resulting in different permeability coefficients. The permeability coefficients of the upper three modules satisfy the following order: left section 2-1 (15.0-20.0 m / d) > middle section 2-2 (10.0-15.0 m / d) > right section 2-3 (5-10.0 m / d). The permeability coefficients of the middle three modules satisfy the following order: left section 2-4 (10.0-15.0 m / d). The permeability coefficients of the three lower modules satisfy the following: left section 2-7 (5.0-10.0 m / d) > middle section 2-8 (2.0-5.0 m / d) > right section 2-9 (0.5-2.0 m / d). Accordingly, the nine modules of the permeable boundary 2 have different permeability coefficients to adjust the effluent from the artificial wetland 1 to have sufficient residence time in the permeable boundary 2, and to enable the effluent from the permeable boundary 2 to flow evenly into the soil vadose zone 3.

[0038] In practical applications, the surface elevation of the main filler area 6 and the permeable boundary 2 of the constructed wetland is not higher than the surface elevation of the vadose zone 3 of the soil, and the bottom elevation of the constructed wetland 1 is higher than the groundwater level.

[0039] In practical applications, in a permeable flexible boundary constructed wetland system, the permeability coefficient of the main filler area 6 of the constructed wetland is 50.0-100.0 m / d, and the permeability coefficient of the permeable boundary 2 is 0.5-20.0 m / d.

[0040] The permeable flexible boundary constructed wetland system selects a permeable boundary for its effluent. This permeable boundary is filled with enhanced phosphorus removal material. A portion of the treated effluent slowly enters the permeable boundary, achieving enhanced phosphorus removal. Then, it flows out through the permeable boundary into the vadose zone of the soil, where its denitrification capacity is further enhanced. Finally, the effluent, after further purification by the vadose zone, is discharged into the natural system, achieving a flexible integration of the constructed wetland and the natural system. Ultimately, this system achieves a flexible integration of the constructed wetland ecological restoration system with the natural system, simultaneously enhancing and reducing nitrogen and phosphorus pollution, while avoiding the disruption of underground runoff channels and the fragmentation of biodiversity during the restoration process.

[0041] Based on the above technical solutions, and taking specific numerical examples, the technical effects of the present invention are verified:

[0042] 1. A flexible integrated system of constructed wetlands and natural systems is designed for rural domestic sewage treatment, with a designed treatment capacity of 200 m³. 3 / d.

[0043] 2. Establish a permeable, flexible boundary constructed wetland system, such as... Figure 1 and Figure 2 As shown.

[0044] 3. An inlet pipe 4 is installed in front of constructed wetland 1 to allow wastewater to enter the constructed wetland distribution area 5. Constructed wetland 1 is a horizontal subsurface flow constructed wetland, with a length of 40m, a width of 15m, and a total construction area of ​​600m². 2 The main body of the wastewater treatment consists of the main filling material area 6 and the wetland plants 7 planted above it; the wetland plants 7 are planted with reeds, cattails, canna lilies, etc.; the main filling material area 6 of the artificial wetland is filled with quartz sand, activated carbon, gravel, etc. from top to bottom, and the total depth from the surface of the filling material is 1.0m.

[0045] 4. The effluent boundary of constructed wetland 1 is selected as a permeable boundary 2, while the left boundary 10, right boundary 11, and bottom boundary 12 are impermeable boundaries. A geomembrane is laid at the bottom of constructed wetland 1 for seepage prevention, and concrete walls are used for the other three sides for seepage prevention. The hydraulic retention time of wastewater in constructed wetland 2 is 1.0 day, and the hydraulic load is 0.4 m. 3 / (m 2 ·d).

[0046] 5. The outlet end of the constructed wetland 1 is provided with a permeable boundary 2. This boundary is an extension of the constructed wetland 1 and is trapezoidal in shape. The angle 2-10 between the left and right sides (sleeves) of the trapezoid and the constructed wetland is 45°. A drainage pipe 13 is laid at the bottom of the permeable boundary 2 to discharge the overloaded water from the constructed wetland 1 into the collection well 14, and then discharge it through the overflow hole 15 on the collection well 14.

[0047] 6. The permeable boundary 2 has a modular structure, employing a three-section structure both horizontally from left to right and vertically from top to bottom, forming nine modules. Each module is filled with a mixture of wood-based biochar, zeolite, diatomaceous earth, and volcanic rock to enhance phosphorus removal. Different proportions of clay are added to create different permeability coefficients. The specific permeability coefficients of each module are as follows: upper left section 2-1: 18 m / d; upper middle section 2-2: 13 m / d; upper right section: 8 m / d; middle left section 2... -4 is 12m / d, the middle section 2-5 is 9m / d, the middle right section 2-6 is 5m / d, the lower left section 2-7 is 8m / d, the lower middle section 2-8 is 4m / d, and the lower right section 2-9 is 2m / d. Because the permeability coefficient of the permeable boundary 2 generally decreases from left to right and from top to bottom, this can adjust the water effluent from the artificial wetland 1 to have sufficient residence time in the permeable boundary 2, and enable the water effluent from the permeable boundary 2 to flow evenly into the soil vadose zone 3.

[0048] 7. The surface elevation of the main filler area 6 and the permeable boundary 2 of the constructed wetland system is 0.1m lower than the surface elevation of the vadose zone 3 of the soil, and the bottom elevation of the constructed wetland 1 is 3.0m higher than the groundwater level.

[0049] 8. The permeability coefficient of the main filler area 6 of the constructed wetland is 60.0 m / d, the permeability coefficient of the permeable boundary 2 is 2.0-18.0 m / d, and the permeability coefficient of the soil vadose zone 3 is 0.6 m / d (in natural conditions, without human intervention).

[0050] 9. For this permeable flexible boundary constructed wetland system, the effluent from constructed wetland 1 flows into the soil vadose zone 3 through the permeable boundary 2, and the effluent after further purification by the soil vadose zone 3 is discharged into the natural system, realizing the flexible integration of constructed wetland and natural system.

[0051] 10. The water that cannot be absorbed by the other part of the soil vadose zone system 2 enters the water collection well 14 through the drainage pipe 13, and then is discharged through the overflow hole 15 on the water collection well 14.

[0052] Therefore, this permeable flexible boundary constructed wetland system couples the constructed wetland and the soil vadose zone through the permeable boundary, and finally discharges the deeply enhanced effluent into the natural system through the soil vadose zone, realizing the flexible integration of the constructed wetland ecological restoration system and the natural system, as well as the simultaneous enhanced reduction of nitrogen and phosphorus pollution.

[0053] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0054] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A permeable flexible boundary constructed wetland system, characterized in that, The structure includes an artificial wetland, a permeable boundary, and a vadose zone in the soil. One end of the artificial wetland is its inlet boundary, and its two sides are its front and rear boundaries, respectively. The bottom of the artificial wetland is its bottom boundary. The inlet boundary, front boundary, rear boundary, and bottom boundary are all impermeable boundaries. The other end of the artificial wetland communicates with the vadose zone in the soil through the permeable boundary. The permeable boundary extends horizontally from left to right... The structure adopts a three-section design from top to bottom in both the right and vertical directions, forming nine modules. These nine modules are: upper left section of the permeable boundary module, upper middle section of the permeable boundary module, upper right section of the permeable boundary module, middle left section of the permeable boundary module, middle middle section of the permeable boundary module, middle right section of the permeable boundary module, lower left section of the permeable boundary module, lower middle section of the permeable boundary module, and lower right section of the permeable boundary module. Each module is filled with a mixture of phosphorus removal material and clay in different proportions to form different permeability coefficients.

2. The permeable flexible boundary constructed wetland system according to claim 1, characterized in that, The permeability coefficient of the upper left section of the permeable boundary module is 15.0-20.0 m / d; The permeability coefficient of the upper middle section of the permeable boundary module is 10.0-15.0 m / d; The permeability coefficient of the upper right section of the permeable boundary module is 5-10.0 m / d; The permeability coefficient of the middle left section of the permeable boundary module is 10.0-15.0 m / d; The permeability coefficient of the middle section of the permeable boundary module is 5.0-10.0 m / d; The permeability coefficient of the right section of the permeable boundary module is 2.0-5.0 m / d; The permeability coefficient of the lower left section of the permeable boundary module is 5.0-10.0 m / d; The permeability coefficient of the lower middle section of the permeable boundary module is 2.0-5.0 m / d; The permeability coefficient of the lower right section of the permeable boundary module is 0.5-2.0 m / d.

3. The permeable flexible boundary constructed wetland system according to claim 2, characterized in that, The permeability coefficient of the upper left section of the permeable boundary module is greater than that of the upper middle section of the permeable boundary module, which is greater than that of the upper right section of the permeable boundary module. The permeability coefficient of the middle left section of the permeable boundary module is greater than that of the middle middle section of the permeable boundary module, which is greater than that of the middle right section of the permeable boundary module. The permeability coefficient of the lower left section of the permeable boundary module is greater than that of the lower middle section of the permeable boundary module, which is greater than that of the lower right section of the permeable boundary module.

4. The permeable flexible boundary constructed wetland system according to claim 1, characterized in that, The permeable boundary has a trapezoidal structure, and the width of the permeable boundary gradually increases from the artificial wetland to the soil vadose zone.

5. The permeable flexible boundary constructed wetland system according to claim 4, characterized in that, The angle between the front and rear sides of the permeable boundary and the artificial wetland is 30°-50°.

6. The permeable flexible boundary constructed wetland system according to claim 1, characterized in that, The length-to-width ratio of the main filler material area of ​​the constructed wetland is controlled to be below 3:1, and the filling height of the main filler material area of ​​the constructed wetland is in the range of 0.8-1.5m.

7. The permeable flexible boundary constructed wetland system according to claim 1, characterized in that, The hydraulic retention time of wastewater in the constructed wetland is 1.0-1.3 days, and the hydraulic loading is 0.3-0.4 m³. 3 / (m 2 ·d).

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