A constructed wetland optimization system suitable for different influent carbon-nitrogen ratios

Abstract

The present application discloses an artificial wetland optimization system suitable for different influent carbon-nitrogen ratios, which includes a front basalt fiber contact oxidation zone, in which a bundled modified basalt fiber bundle is suspended, on which a group of prefabricated basalt fiber bio-nests are bundled, and a slow-release carbon source groove is provided on the pool wall to add a slow-release carbon source; secondly, a horizontal flow artificial wetland filtration zone is provided in series after the contact oxidation zone; when the influent carbon-nitrogen ratio is relatively low, wastewater enters from both sides of the slow-release carbon source groove, and after sufficient contact, flows into the water distribution pipe at the front end of the basalt fiber contact oxidation zone and flows out from the end of the horizontal flow artificial wetland filtration zone; when the influent carbon source is sufficient, the sewage flows directly into the water inlet pipe at the front end of the contact oxidation zone and flows out from the end of the artificial wetland; the process of the present invention is simple, easy to operate, and environmentally friendly; the designed combined system has sufficient and replaceable carbon source, good chemical and biological stability, and the basalt fiber bio-nest can promote the attachment of microorganisms on its surface, thereby improving the sewage treatment efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of organic sewage (wastewater) treatment, and in particular to an artificial wetland optimization system suitable for different influent carbon-nitrogen ratios. Background Art

[0002] Constructed wetlands (CWs) are a mature ecological wastewater treatment technology with low construction and operating costs, as well as sustainability and ecological benefits. They combine large plants, microorganisms and wetland matrices, and combine multiple synergistic effects of physical, chemical and biological processes to achieve efficient sewage treatment in multiple ways and in all aspects. On the other hand, horizontal subsurface flow constructed wetlands also have the advantages of simple operation, low cost and resistance to shock loads. Therefore, constructed wetlands are widely used in the purification of various polluted water bodies such as domestic sewage, industrial and agricultural wastewater, mining sewage and landfill leachate to remove conventional pollutants. In addition, through plant absorption, bacterial bioaccumulation and substrate adsorption, constructed wetlands can also effectively remove new persistent pollutants that are difficult to degrade in general sewage treatment plants.

[0003] Currently, constructed wetlands are primarily used in the advanced treatment of wastewater treatment plants, specifically tailwater treatment. Because tailwater is of better quality than sewage and relatively poor in nutrients, subsequent treatment may result in reduced efficiency due to insufficient carbon sources. Therefore, adding a stable, sustainable, and easily degradable biocarbon source (such as plant straw) to the tailwater wetland can improve the carbon-nitrogen ratio of the influent, promote pollutant degradation, and enhance the operational performance of the tailwater treatment wetland.

[0004] Basalt fiber (BF) is a high-performance fiber with both economic and ecological benefits. It boasts a large specific surface area, excellent chemical and biological stability, high-temperature and corrosion resistance, and no secondary pollution. Currently, basalt fiber is being applied in wastewater treatment due to its many advantages. Basalt fiber bionests form a three-dimensional structure with multiple dissolved oxygen gradients—aerobic at the periphery and anoxic at the core—thus providing a large biomass and creating a rich microenvironment, ultimately improving the performance and efficiency of wastewater purification.

[0005] However, in the existing basalt fiber artificial wetlands, basalt fiber is mostly used as wetland filler, and there is no combination of basalt fiber contact oxidation pond and artificial wetland in series, nor is there any introduction of replaceable slow-release carbon source to alleviate the problem of insufficient carbon source in tail water.

[0006] Chinese patent CN115124188A discloses a modified concrete nitrogen and phosphorus removal filter bed connected in series with a large water surface terraced wetland and method. For ecological wetlands that improve the water quality of sewage plant tailwater, it is 2 to 5 times the surface flow hydraulic load value recommended in the "Guidelines for Water Purification Technology of Constructed Wetlands" and is suitable for low carbon and nitrogen ratio tailwater from urban sewage plants. The skeleton filter dam uses basalt gravel with a particle size of 15-25mm. However, this design is connected in series with a modified concrete filter bed, which is an optimization and upgrade based on the surface flow wetland and occupies a large area. At the same time, the modified filler in the filter bed cannot be regenerated, and the stability and sustainability of subsequent operation need to be improved. The existing technology is slightly insufficient. This application is a combined design that connects a contact oxidation pond with a horizontal subsurface flow artificial wetland in series. It occupies a small area and is suitable for the treatment module of a sewage treatment plant. The zoned water inlet design is more flexible to respond to different inlet carbon-nitrogen ratios, and the plant slow-release carbon source can be replaced and regenerated, making the system more sustainable. In addition, the suspended bio-nested modified basalt fiber can greatly enhance the bioaccumulation performance of the filler, which can not only treat conventional pollutants, but also has the potential to resist new pollutants such as persistent organic matter. Summary of the Invention

[0007] Technical Problems Solved: In response to the existing problems of different types of wastewater with different carbon-nitrogen ratios, lack of nutrients in some tail water treatment, and low purification efficiency, the present invention provides an artificial wetland optimization system suitable for different influent carbon-nitrogen ratios. Technical Solution:

[0008] A constructed wetland optimization system suitable for different influent carbon-nitrogen ratios comprises a contact oxidation zone and a constructed wetland filtration zone, wherein a perforated partition is provided between the contact oxidation zone and the constructed wetland filtration zone, a cover plate is provided on the top of the contact oxidation zone, and a base plate is provided at the bottom of the contact oxidation zone. Both the bottom of the cover plate and the upper surface of the base plate are provided with detachable stainless steel wire meshes, and a group of bundled modified basalt fiber bundles are fixed between the bottom of the cover plate and the detachable stainless steel wire mesh on the base plate; the upper and lower ends of the bundled modified basalt fiber bundles are knotted and fixed to the detachable stainless steel wire mesh; and a plurality of prefabricated basalt fiber bionests are bundled on the bundled modified basalt fiber bundles;

[0009] The detachable stainless steel wire mesh at the bottom of the cover plate is connected to a water distribution pipe with small holes on it, and a water inlet pipe A is provided above the detachable stainless steel wire mesh at the top of the bottom plate; slow-release carbon source grooves are provided on the left and right sides of the contact oxidation zone, and a water inlet pipe B is provided at the bottom of the slow-release carbon source groove, and the top of the slow-release carbon source groove is connected to the water distribution pipe; low carbon-nitrogen ratio sewage enters from the water inlet pipe B at the bottom of both sides of the slow-release carbon source groove, passes through the water distribution pipe, and enters the contact oxidation zone through the small holes, and high carbon-nitrogen ratio sewage enters directly from the water inlet pipe A.

[0010] As a preferred technical solution of the present invention: a row of holes is opened at the top of the perforated partition, and the rest are all sealed; the artificial wetland filtration zone is supplied with water from the contact oxidation zone through the holes at the top of the perforated partition; an outlet pipe is provided at the bottom of the artificial wetland filtration zone, and water is discharged from the artificial wetland filtration zone through the outlet pipe at the bottom.

[0011] As a preferred technical solution of the present invention: the bundled modified basalt fiber bundle is suspended and fixed in the contact oxidation zone, and the two ends are fixed to ensure that the bundled modified basalt fiber bundle will not be washed away by horizontal water flow, and the prefabricated basalt fiber bio-nest is modified with polydopamine.

[0012] As an optimal technical solution of the present invention: the walls of the slow-release carbon source grooves on the left and right sides of the contact oxidation zone are sealed, the lower ends are connected to the water inlet pipes B on both sides, and the upper ends are connected to the water distribution pipes of the contact oxidation zone, and hooks are provided at both ends of the top of the slow-release carbon source groove; a replaceable mesh bag is provided inside the slow-release carbon source groove, the mesh bag is fixed to the hooks at both ends of the top of the slow-release carbon source groove, and the mesh bag is filled with a slow-release plant carbon source; the slow-release plant carbon source is straw and / or corn cob fragments.

[0013] As a preferred technical solution of the present invention: the edges around the bottom surface of the cover plate and the top surface of the base plate are provided with protruding structures for fixing the detachable stainless steel wire mesh, and the detachable stainless steel wire mesh is fixed to the protruding structures by screws.

[0014] As a preferred technical solution of the present invention: the top of the slow-release carbon source tank is not capped, and the detachable stainless steel wire meshes on the cover plate and the bottom plate are detachable.

[0015] As a preferred technical solution of the present invention, the preparation of bundled modified basalt fiber bundles includes the following steps:

[0016] Step 1: Preparation of polydopamine modified basalt fiber

[0017] 1) Weigh 40g of basalt fiber and immerse it in 500ml of acetone solution. Place it in an ultrasonic cleaner and clean it for 3 hours. After removing it, rinse it repeatedly with deionized water and dry it at 105℃ for 4 hours.

[0018] 2) Prepare 0.5 mol / L NaOH solution, soak the basalt fiber in the NaOH solution, take it out after 2 hours, rinse it with deionized water several times until it is neutral, and dry it for later use;

[0019] 3) Prepare Tris-HCl buffer: Prepare a 15 mmol / L Tris solution using tris(hydroxymethyl)aminomethane solution, then add HCl to adjust the pH to 8.0-8.5;

[0020] 4) Preparation of dopamine-modified solution: dissolving dopamine and ammonium persulfate in Tris-HCl buffer to prepare a dopamine-modified solution with an initial concentration of 2 mg / mL;

[0021] 5) soaking the basalt fiber prepared in step 2) in the dopamine-modified solution prepared in step 4), shaking the solution in a shaker at 20-25° C. for 24 hours, removing the solution, and drying the solution at 40-50° C. for 2 hours to obtain polydopamine-modified basalt fiber;

[0022] Step 2: Preparation of bundled modified basalt fiber bundles

[0023] Step 1: polydopamine-modified basalt fibers are bundled into nests to produce prefabricated basalt fiber bio-nests, and the prefabricated basalt fiber bio-nests are then bundled to produce bundled modified basalt fiber bundles. Seed sludge and sewage are collected from a sewage treatment plant to acclimate microorganisms.

[0024] Step 2: Hang the bundled modified basalt fiber bundle in a pre-cultured contact oxidation device, control the pH of the device to 7.5±0.3, control the dissolved oxygen to 1-2 mg / L, and maintain the temperature at 25.0±3.0°C;

[0025] Step 3: The influent nutrient ratio of the device is C:N:P = 100:5:1, the mixed liquid suspended solids (MLSS) concentration is 5200 mg / L, and the mixed liquid volatile suspended solids to MLSS ratio (MLVSS / MLSS) is 0.68; a mixture of seed sludge and sewage is added to each reactor at a ratio of 1:1;

[0026] Step 4: During the acclimation process, the inlet flow rate was gradually increased, and the hydraulic retention time was steadily shortened from 24 h to 10 h;

[0027] Step 5, adding trace mineral and vitamin solutions to each contact oxidation device to support the growth and proliferation of the microbial community;

[0028] Step 6: After acclimation for 30 days, bundled modified basalt fiber bundles were successfully formed in each device.

[0029] As a preferred technical solution of the present invention: the artificial wetland filtration area is filled with a matrix, and emergent plants are planted above the matrix.

[0030] As a preferred technical solution of the present invention: the matrix is ​​a single layer or multiple layers, selected according to the water quality of the influent, and the matrix is ​​one or more of sand, gravel, vermiculite, ceramsite, and activated carbon.

[0031] As a preferred technical solution of the present invention: the emergent plant is the perennial yellow calamus.

[0032] Principle explanation: low carbon-nitrogen ratio sewage / tail water enters the slow-release carbon source tank from the water inlet pipes on both sides and fully contacts with the plant carbon source, then flows into the water distribution pipe at the upper end of the contact oxidation zone, and enters the contact oxidation pool area through the small holes in the water distribution pipe. Sewage with sufficient carbon source can directly flow into the contact oxidation zone through the front water inlet pipe; when the carbon source is sufficient, the influent fully contacts with several bio-nests on the bundled modified basalt fiber bundles hanging in the contact oxidation zone and fully reacts, and denitrification and phosphorus removal and organic matter degradation are carried out by the functional microorganisms on the basalt fiber bio-nests; the slow-release carbon source tank is not capped and is connected to the air, which can supplement the dissolved oxygen in the contact oxidation zone, which is beneficial to improve the pollutant removal efficiency; after the reaction, The sewage / tail water enters the artificial wetland filtration area through the holes in the upper layer of the perforated partition, and is further purified under the synergistic effect of the wetland matrix, plants and microorganisms. Compared with the traditional horizontal submerged artificial wetland, this combined artificial wetland system connects the basalt fiber contact oxidation tank and the artificial wetland in series. On the one hand, it can effectively enhance the treatment effect by increasing the carbon-nitrogen ratio of the influent by adding a slow-release carbon source. On the other hand, it also combines the advantages of basalt fiber bio-nests and artificial wetlands, and is an optimized ecological sewage treatment device. In addition, the zoned water inlet method also takes into account the influent characteristics of different carbon-nitrogen ratio conditions, and has the ability to flexibly treat a variety of sewage / tail water.

[0033] Beneficial effects:

[0034] Compared with the existing technology, this application has the following advantages:

[0035] 1. The basalt fiber used in the present invention has excellent mechanical, thermal properties and chemical stability. Due to its large specific surface area, it is more conducive to the attachment and biofilm formation of microorganisms. It also has both economic and environmental benefits and is a new type of excellent water treatment material.

[0036] 2. The pre-prepared basalt fiber bio-nest of the present invention gathers functional microorganisms for pollutant degradation by inoculating sludge and acclimating, thereby increasing the microbial loading rate and microbial degradation capacity;

[0037] 3. The contact oxidation zone of the present invention is equipped with a slow-release carbon source tank, in which a replaceable mesh bag is hung. The mesh bag can be filled with a plant carbon source to increase the carbon-nitrogen ratio of the influent. At the same time, the carbon source can be updated by replacing the mesh bag, ensuring that the contact oxidation zone always has sufficient carbon source, which is more conducive to microbial denitrification and phosphorus removal.

[0038] 4. The present invention adopts a zoned water inlet method, which can take into account the inlet characteristics of sewage or tail water with different carbon-nitrogen ratios and has the ability to flexibly treat a variety of sewage / tail water;

[0039] 5. The ends of the bundled modified basalt fiber bundles in the present invention are fixed to the stainless steel wire mesh connecting the cover and bottom plates, which can prevent the fiber bundles from falling off due to horizontal erosion by water flow. The hanging position, hanging quantity and hanging angle of the basalt fiber bundles can be changed by different combinations of the upper and lower grids, which provides flexibility.

[0040] 6. The emergent plants selected in the present invention, such as yellow iris, have the characteristics of easy growth, developed root system, resistance to shock load, strong adsorption capacity, etc., and have a good effect on removing conventional nutrients in water bodies and have certain removal potential for some persistent organic matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a top view of the combined basalt fiber horizontal flow artificial wetland of the present invention;

[0042] Figure 2 This is a top view of the water inlet direction of the combined basalt fiber horizontal flow artificial wetland of the present invention;

[0043] Figure 3 This is the AA cross-sectional view of the combined basalt fiber horizontal flow artificial wetland of the present invention;

[0044] Figure 4 This is the BB cross-section of the combined basalt fiber horizontal flow artificial wetland of the present invention;

[0045] Figure 5 This is a cross-sectional view of the combined basalt fiber horizontal flow constructed wetland in the water inlet direction BB of the present invention;

[0046] Figure 6 This is a structural diagram of the cover plate and bottom plate of the present invention;

[0047] Figure 7 This is a schematic diagram of the upper and lower fixation of the basalt fiber bundles of the present invention.

[0048] Explanation of the accompanying symbols: 1. Water inlet pipe A, 2. Water distribution pipe, 3. Water inlet pipe B, 4. Contact oxidation zone, 5. Cover plate, 6. Bottom plate, 7. Bundled modified basalt fiber bundle, 8. Prefabricated basalt fiber bio-nest, 9. Partition, 10. Emergent plant, 11. Artificial wetland filtration zone, 12. Matrix, 13. Water outlet pipe, 14. Slow-release carbon source trough, 15. Mesh bag, 16. Slow-release plant carbon source, 17. Removable stainless steel wire mesh, 18. Protruding structure, 19. Hook, 20. Small hole. DETAILED DESCRIPTION

[0049] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0050] Example 1

[0051] An optimized artificial wetland system suitable for different influent carbon-nitrogen ratios, the contact oxidation zone and artificial wetland filtration zone combined system composition see Figure 1 、 Figure 2 :

[0052] The invention comprises a contact oxidation zone 4 and an artificial wetland filtration zone 11, wherein a perforated partition plate 9 is provided between the contact oxidation zone 4 and the artificial wetland filtration zone 11, a cover plate 5 is provided on the top of the contact oxidation zone 4, and a base plate 6 is provided on the bottom of the contact oxidation zone 4. A detachable stainless steel wire mesh 17 is installed on the bottom of the cover plate 5 and the upper surface of the base plate 6. A group of bundled modified basalt fiber bundles 7 is fixed between the bottom of the cover plate 5 and the detachable stainless steel wire mesh 17 on the base plate 6; the upper and lower ends of the bundled modified basalt fiber bundles 7 are knotted and fixed to the detachable stainless steel wire mesh 17; and a plurality of prefabricated basalt fiber bio-nests 8 are bundled on the bundled modified basalt fiber bundles 7;

[0053] The removable stainless steel mesh 17 at the bottom of the cover plate 5 is connected to a water distribution pipe 2 with small holes 20. A water inlet pipe A1 is located above the removable stainless steel mesh 17 at the top of the base plate 6. The contact oxidation zone 4 is flanked by slow-release carbon source tanks 14, each with a water inlet pipe B3 at its bottom. The top of each tank is connected to the water distribution pipe 2. Low-carbon-nitrogen ratio wastewater enters the contact oxidation zone 4 through the water inlet pipes B3 on either side of the slow-release carbon source tanks 14, passes through the water distribution pipe 2, and enters the contact oxidation zone 4 through the small holes 20. High-carbon-nitrogen ratio wastewater enters directly through the water inlet pipe A1. After sufficient reaction in the contact oxidation zone 4, the wastewater passes through the perforated partition 9 and enters the constructed wetland filtration zone. There, it is deeply degraded by the multiple actions of emergent plants 10, microorganisms, and substrate 12 before flowing out through the outlet pipe 13.

[0054] A row of holes is opened at the top of the perforated partition 9, and the rest are all sealed. The artificial wetland filtration area 11 takes in water from the contact oxidation area 4 through the holes at the top of the perforated partition 9. An outlet pipe 13 is provided at the bottom of the artificial wetland filtration area 11, and water is discharged from the artificial wetland filtration area 11 through the outlet pipe 13 at the bottom.

[0055] The bundled modified basalt fiber bundle 7 is suspended and fixed in the contact oxidation zone 4, and the two ends are fixed to ensure that the bundled modified basalt fiber bundle will not be washed away by the horizontal water flow. The prefabricated basalt fiber bio-nest 8 is modified with polydopamine to improve hydrophilicity and biocompatibility.

[0056] The walls of the slow-release carbon source grooves 14 on the left and right sides of the contact oxidation zone 4 are sealed, the lower ends are connected to the water inlet pipes B 3 on both sides, and the upper ends are connected to the water distribution pipes 2 of the contact oxidation zone 4. Hooks 19 are provided at both ends of the top of the slow-release carbon source grooves 14; a replaceable mesh bag 15 is provided inside the slow-release carbon source groove 14, and the mesh bag 15 is fixed to the hooks 19 at both ends of the top of the slow-release carbon source groove 14. The mesh bag 15 is filled with a slow-release plant carbon source 16; the slow-release plant carbon source 16 is straw and / or corn cob debris. The plant carbon source is replaced by replacing the mesh bag to ensure that the contact oxidation zone has sufficient carbon source.

[0057] The bottom surface of the cover plate 5 and the top surface of the bottom plate 6 are provided with protruding structures 18 for fixing the detachable stainless steel wire mesh 17 . The detachable stainless steel wire mesh 17 is fixed to the protruding structures 18 by screws.

[0058] The top of the slow-release carbon source tank 14 is not sealed and is connected to the air, which can replenish the dissolved oxygen in the contact oxidation zone, thereby improving the pollutant removal efficiency.

[0059] The detachable stainless steel wire mesh 17 on the cover plate 5 and the bottom plate 6 is detachable for easy cleaning and replacement.

[0060] The artificial wetland filtration area 11 is filled with a matrix 12 , and emergent plants 10 are planted above the matrix 12 .

[0061] The matrix 12 is a single layer or multiple layers, which is selected according to the water quality of the influent. The matrix 12 is one or more of sand, gravel, vermiculite, ceramsite, and activated carbon.

[0062] The emergent plant 10 is a perennial yellow calamus, which has the characteristics of easy growth, well-developed root system, resistance to shock load, and strong adsorption capacity. It has a good effect on removing conventional nutrients in water bodies and has a certain potential for removing some persistent organic matter.

[0063] Example 2

[0064] A constructed wetland optimization system suitable for different influent carbon-nitrogen ratios, wherein the preparation of bundled modified basalt fiber bundles comprises the following steps:

[0065] Step 1: Preparation of polydopamine modified basalt fiber

[0066] 1) Weigh 40g of basalt fiber and immerse it in 500ml of acetone solution. Place it in an ultrasonic cleaner and clean it for 3 hours. After removing it, rinse it repeatedly with deionized water and dry it at 105℃ for 4 hours.

[0067] 2) Prepare 0.5 mol / L NaOH solution, soak the basalt fiber in the NaOH solution, take it out after 2 hours, rinse it with deionized water several times until it is neutral, and dry it for later use;

[0068] 3) Prepare Tris-HCl buffer: Prepare a 15 mmol / L Tris solution using tris(hydroxymethyl)aminomethane solution, then add HCl to adjust the pH to 8.0-8.5;

[0069] 4) Preparation of dopamine-modified solution: dissolving dopamine and ammonium persulfate in Tris-HCl buffer to prepare a dopamine-modified solution with an initial concentration of 2 mg / mL;

[0070] 5) soaking the basalt fiber prepared in step 2) in the dopamine-modified solution prepared in step 4), shaking the solution in a shaker at 20-25° C. for 24 hours, removing the solution, and drying the solution at 40-50° C. for 2 hours to obtain polydopamine-modified basalt fiber;

[0071] Step 2: Preparation of bundled modified basalt fiber bundles

[0072] Step 1: polydopamine-modified basalt fibers are bundled into nests to produce prefabricated basalt fiber bio-nests, and the prefabricated basalt fiber bio-nests are then bundled to produce bundled modified basalt fiber bundles. Seed sludge and sewage are collected from a sewage treatment plant to acclimate microorganisms.

[0073] Step 2: Hang the bundled modified basalt fiber bundle in a pre-cultured contact oxidation device, control the pH of the device to 7.5±0.3, control the dissolved oxygen to 1-2 mg / L, and maintain the temperature at 25.0±3.0°C;

[0074] Step 3: The influent nutrient ratio of the device is C:N:P = 100:5:1, the mixed liquid suspended solids (MLSS) concentration is 5200 mg / L, and the mixed liquid volatile suspended solids to MLSS ratio (MLVSS / MLSS) is 0.68; a mixture of seed sludge and sewage is added to each reactor at a ratio of 1:1;

[0075] Step 4: During the acclimation process, the inlet flow rate was gradually increased, and the hydraulic retention time was steadily shortened from 24 h to 10 h;

[0076] Step 5, adding trace mineral and vitamin solutions to each contact oxidation device to support the growth and proliferation of the microbial community;

[0077] Step 6: After acclimation for 30 days, bundled modified basalt fiber bundles were successfully formed in each device.

[0078] The description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. It should be pointed out that for those skilled in the art, the present invention can be improved and modified without departing from the principles of the invention. These improvements and modifications are also within the scope of protection of the claims of the present invention.

Claims

1. A constructed wetland optimization system suitable for different influent carbon-nitrogen ratios, characterized by: The invention comprises a contact oxidation zone (4) and an artificial wetland filtration zone (11), wherein a perforated partition plate (9) is provided between the contact oxidation zone (4) and the artificial wetland filtration zone (11), a cover plate (5) is provided on the top of the contact oxidation zone (4), and a base plate (6) is provided on the bottom of the contact oxidation zone (4), and a detachable stainless steel wire mesh (17) is installed on the bottom of the cover plate (5) and the upper surface of the base plate (6), and a group of bundled modified basalt fiber bundles (7) are fixed between the bottom of the cover plate (5) and the detachable stainless steel wire mesh (17) on the base plate (6); the upper and lower ends of the bundled modified basalt fiber bundles (7) are knotted and fixed on the detachable stainless steel wire mesh (17); and a plurality of prefabricated basalt fiber bio-nests (8) are bundled on the bundled modified basalt fiber bundles (7); The lower part of the detachable stainless steel wire mesh (17) at the bottom of the cover plate (5) is connected to a water distribution pipe (2), and a small hole (20) is opened on the water distribution pipe (2). A water inlet pipe A (1) is provided above the detachable stainless steel wire mesh (17) at the top of the bottom plate (6); the left and right sides of the contact oxidation zone (4) are provided with a slow-release carbon source groove (14), and the bottom of the slow-release carbon source groove (14) is provided with a water inlet pipe B (3), and the top of the slow-release carbon source groove (14) is connected to the water distribution pipe (2); low carbon-nitrogen ratio sewage enters from the water inlet pipe B (3) at the bottom of both sides of the slow-release carbon source groove (14), passes through the water distribution pipe (2), and enters the contact oxidation zone (4) through the small hole (20), and high carbon-nitrogen ratio sewage enters directly from the water inlet pipe A (1).

2. The constructed wetland optimization system applicable to different influent carbon-nitrogen ratios according to claim 1, characterized in that: A row of holes is provided at the top of the perforated partition (9), and the rest are all sealed. Water enters the artificial wetland filtration zone (11) from the contact oxidation zone (4) through the holes at the top of the perforated partition (9). A water outlet pipe (13) is provided at the bottom of the artificial wetland filtration zone (11), and water is discharged from the artificial wetland filtration zone (11) through the water outlet pipe (13) at the bottom.

3. The constructed wetland optimization system applicable to different influent carbon-nitrogen ratios according to claim 2, characterized in that: The bundled modified basalt fiber bundle (7) is suspended and fixed in the contact oxidation zone (4), and the two ends are fixed to ensure that the bundled modified basalt fiber bundle will not be washed away by horizontal water flow, and the prefabricated basalt fiber bio-nest (8) is modified with polydopamine.

4. The constructed wetland optimization system applicable to different influent carbon-nitrogen ratios according to claim 1, characterized in that: The walls of the slow-release carbon source grooves (14) on the left and right sides of the contact oxidation zone (4) are sealed, the lower ends are connected to the water inlet pipes B (3) on both sides, and the upper ends are connected to the water distribution pipes (2) of the contact oxidation zone (4). Hooks (19) are provided at both ends of the top of the slow-release carbon source groove (14); a replaceable mesh bag (15) is provided inside the slow-release carbon source groove (14), the mesh bag (15) is fixed to the hooks (19) at both ends of the top of the slow-release carbon source groove (14), and the mesh bag (15) is filled with a slow-release plant carbon source (16); the slow-release plant carbon source (16) is straw and / or corn cob debris.

5. The constructed wetland optimization system applicable to different influent carbon-nitrogen ratios according to claim 1, characterized in that: The bottom surface of the cover plate (5) and the top surface of the base plate (6) are provided with protruding structures (18) for fixing the detachable stainless steel wire mesh (17) on their edges. The detachable stainless steel wire mesh (17) is fixed to the protruding structures (18) by screws.

6. The constructed wetland optimization system applicable to different influent carbon-nitrogen ratios according to claim 1, characterized in that: The top of the slow-release carbon source tank (14) is not capped, and the detachable stainless steel wire mesh (17) on the cover plate (5) and the bottom plate (6) is detachable.

7. The constructed wetland optimization system applicable to different influent carbon-nitrogen ratios according to claim 1, characterized in that: The preparation of bundled modified basalt fiber bundles includes the following steps: Step 1: Preparation of polydopamine modified basalt fiber 1) Weigh 40g of basalt fiber and immerse it in 500ml of acetone solution. Place it in an ultrasonic cleaner and clean it for 3 hours. After removing it, rinse it repeatedly with deionized water and dry it at 105℃ for 4 hours. 2) Prepare 0.5 mol / L NaOH solution, soak the basalt fiber in the NaOH solution, take it out after 2 hours, rinse it with deionized water several times until it is neutral, and dry it for later use; 3) Prepare Tris-HCl buffer: Prepare a 15 mmol / L Tris solution using tris(hydroxymethyl)aminomethane solution, then add HCl to adjust the pH to 8.0-8.5; 4) Preparation of dopamine-modified solution: dissolving dopamine and ammonium persulfate in Tris-HCl buffer to prepare a dopamine-modified solution with an initial concentration of 2 mg / mL; 5) soaking the basalt fiber prepared in step 2) in the dopamine-modified solution prepared in step 4), shaking the solution in a shaker at 20-25° C. for 24 hours, removing the solution, and drying the solution at 40-50° C. for 2 hours to obtain polydopamine-modified basalt fiber; Step 2: Preparation of bundled modified basalt fiber bundles Step 1: polydopamine-modified basalt fibers are bundled into nests to produce prefabricated basalt fiber bio-nests, and the prefabricated basalt fiber bio-nests are then bundled to produce bundled modified basalt fiber bundles. Seed sludge and sewage are collected from a sewage treatment plant to acclimate microorganisms. Step 2: Hang the bundled modified basalt fiber bundle in a pre-cultured contact oxidation device, control the pH of the device to 7.5±0.3, control the dissolved oxygen to 1-2 mg / L, and maintain the temperature at 25.0±3.0°C; Step 3: The influent nutrient ratio of the device is C:N:P = 100:5:1, the mixed liquid suspended solids (MLSS) concentration is 5200 mg / L, and the mixed liquid volatile suspended solids to MLSS ratio (MLVSS / MLSS) is 0.68; a mixture of seed sludge and sewage is added to each reactor at a ratio of 1:1; Step 4: During the acclimation process, the inlet flow rate was gradually increased, and the hydraulic retention time was steadily shortened from 24 h to 10 h; Step 5, adding trace mineral and vitamin solutions to each contact oxidation device to support the growth and proliferation of the microbial community; Step 6: After acclimation for 30 days, bundled modified basalt fiber bundles were successfully formed in each device.

8. The constructed wetland optimization system applicable to different influent carbon-nitrogen ratios according to claim 1, characterized in that: The artificial wetland filtration area (11) is filled with a matrix (12), and emergent plants (10) are planted above the matrix (12).

9. The constructed wetland optimization system applicable to different influent carbon-nitrogen ratios according to claim 8, characterized in that: The matrix (12) is a single layer or multiple layers, which is selected according to the water quality of the influent. The matrix (12) is one or more of sand, gravel, vermiculite, ceramsite, and activated carbon.

10. The constructed wetland optimization system applicable to different influent carbon-nitrogen ratios according to claim 8, characterized in that: The emergent plant (10) is the perennial yellow calamus.

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