Subsurface flow constructed wetland based on iron-carbon micro-electrolysis for efficient synergistic removal of sulfamethoxazole and total nitrogen

Abstract

The present invention relates to a submerged flow artificial wetland based on iron-carbon micro-electrolysis for efficient and coordinated removal of sulfamethoxazole and total nitrogen. Rope-shaped artificial water plants loaded with iron-carbon micro-electrolysis balls are arranged between unsaturated zones and saturated zones distributed upward and downward along the water flow direction in the packing layer of the downward submerged flow artificial wetland. The beneficial effects are: by creating a good growth and reproduction environment for ammonia oxidizing bacteria, such as a slightly alkaline environment, ferrous particles, rope-shaped artificial water plants, aerobic / anaerobic zones (unsaturated zones / saturated zones), etc., ammonia oxidizing bacteria are promoted to reduce sulfamethoxazole and total nitrogen in artificial wetlands, and the removal rate of sulfamethoxazole and total nitrogen in artificial wetlands is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of artificial wetlands, and in particular to a subsurface artificial wetland for efficiently and synergistically removing sulfamethoxazole and total nitrogen based on iron-carbon micro-electrolysis. Background Art

[0002] The increase in the use of antibiotics in humans and animals and their metabolic defects will inevitably increase the antibiotic load in the environment. Constructed wetlands have been widely used to treat hospital, livestock, domestic sewage and sewage tailwater from sewage treatment plants due to their high treatment efficiency and low operating costs. The use of constructed wetlands to further remove antibiotics from water bodies will help reduce the concentration of antibiotics entering the environment and further reduce the environmental risks of antibiotics. The low carbon-nitrogen ratio of sewage treatment plant tailwater has become a common problem, which limits the improvement of the removal rate of total nitrogen by tailwater artificial wetlands. The anaerobic ammonia oxidation process can efficiently remove nitrogen under low carbon-nitrogen ratio conditions, with low energy consumption and low residual sludge, so it has received widespread attention. At the same time, studies have shown that the removal of sulfamethoxazole in sewage is mainly through direct degradation and synergistic metabolism of microorganisms, and the most critical microorganisms are ammonia oxidizing bacteria, and the effect of aerobic ammonia oxidizing bacteria is more prominent. Therefore, by creating a suitable growth environment for ammonia oxidizing bacteria and enriching ammonia oxidizing bacteria in constructed wetlands, the removal effect of sulfamethoxazole and total nitrogen in constructed wetlands can be improved.

[0003] Ammonia oxidizing bacteria grow slowly and are sensitive to environmental changes, which makes them ineffective in treating sewage. Therefore, maintaining a stable biomass of ammonia oxidizing bacteria in the reaction system and improving their tolerance to changes in the external environment and load are the keys to improving system stability and long-term operation. Microbial immobilization technology is a good solution that can increase the density of microbial attachment and prolong the residence time of microorganisms. Rope-shaped artificial aquatic plants have good water conductivity, specific surface area, and bioaffinity. They are cheap and environmentally friendly, and are widely used for environmental microbial biofilm. The optimal environmental pH for ammonia oxidizing bacteria is 8.0. Therefore, creating slightly alkaline environmental conditions is conducive to the growth of ammonia oxidizing bacteria.

[0004] The iron-carbon micro-electrolysis method belongs to the internal electrolysis method in electrochemical treatment. Its principle is to use iron and carbon to form a primary battery, integrating multiple physical and chemical effects such as oxidation-reduction, physical adsorption, flocculation precipitation, and complex reaction to remove pollutants. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a subsurface artificial wetland based on iron-carbon micro-electrolysis for efficient and synergistic removal of sulfamethoxazole and total nitrogen, so as to overcome the deficiencies in the above-mentioned prior art.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a submerged flow artificial wetland based on iron-carbon micro-electrolysis for efficient and synergistic removal of sulfamethoxazole and total nitrogen, comprising: a downward submerged flow artificial wetland, in which rope-shaped artificial aquatic plants loaded with iron-carbon micro-electrolysis balls are arranged between the unsaturated zone and the saturated zone distributed upward and downward along the water flow direction in the filler layer of the downward submerged flow artificial wetland.

[0007] The beneficial effects of the present invention are:

[0008] Under aerobic conditions, the iron-carbon micro-electrolysis balls loaded on the rope-like artificial water plants undergo micro-electrolysis reactions, thereby releasing ferrous ions (Fe 2+ ) and alkaline substances, while alkaline substances, Fe 2+ The alkaline substances are quickly and effectively transmitted to the ammonia oxidizing bacteria enriched on the rope-shaped artificial water plants. The weakly alkaline environment created by the alkaline substances creates suitable environmental conditions for the growth and reproduction of ammonia oxidizing bacteria that can effectively reduce total nitrogen and sulfamethoxazole, thereby increasing the abundance of ammonia oxidizing bacteria and Fe 2+ It can promote the secretion of extracellular polymers of ammonia oxidizing bacteria and the synthesis of heme C, which can greatly stimulate the activity of ammonia oxidizing bacteria. Through cooperation, it can effectively improve the removal rate of total nitrogen and sulfamethoxazole that rely on the action of ammonia oxidizing bacteria for degradation and metabolism. The whole process is mainly the reduction of pollutants by microorganisms, without producing pollutants and causing negative impact on wetland blockage.

[0009] In an anaerobic environment, the products produced by iron-carbon micro-electrolysis itself (such as [H], i.e., active hydrogen ions) are highly active and can not only remove some refractory substances, but also change the form and structure of some organic matter and improve the biodegradability of water bodies. In addition, the electrons produced by iron-carbon micro-electrolysis are beneficial to the reduction of pollutants.

[0010] In addition, metallic iron can also undergo a replacement reaction with heavy metal ions that rank after iron in the metal activity order in wastewater, and has a good removal effect on some heavy metals;

[0011] The rope-shaped artificial water grass arranged in the packing layer has the following functions: it can extend the water flow path in the unsaturated zone, increase the contact time between microorganisms, iron-carbon balls and sewage; provide a very suitable growth and reproduction environment for the growth of ammonia oxidizing bacteria; it can play a role in heat preservation and insulation, and provide a suitable and good temperature environment for ammonia oxidizing bacteria as much as possible;

[0012] The iron-carbon micro-electrolysis balls are loaded onto rope-shaped artificial aquatic plants. When the artificial wetland fillers are filled, they can be placed according to the set partition ratio. The operation is simple. Both the iron-carbon micro-electrolysis balls and the rope-shaped artificial aquatic plants are relatively cheap and easy to obtain. Combining them together can maximize the potential and utilization rate of the materials, and the cost performance is extremely high.

[0013] Based on the above technical solution, the present invention can also be improved as follows.

[0014] Furthermore, the rope-shaped artificial aquatic plants are placed in the unsaturated zone and the saturated zone in a ratio of 1:(1-2).

[0015] The above further beneficial effect is that both aerobic ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria have a certain removal effect on sulfamethoxazole and total nitrogen. Relatively speaking, aerobic ammonia oxidizing bacteria can better improve the removal effect of sulfamethoxazole, while anaerobic ammonia oxidizing bacteria can better improve the removal rate of total nitrogen. Selecting this ratio can make the removal rates of sulfamethoxazole and total nitrogen higher.

[0016] Furthermore, the materials of the iron-carbon micro-electrolysis balls are: sponge iron, activated carbon, non-degradable plastic and pore-forming materials.

[0017] The above further beneficial effects are: the iron-carbon integrated micro-electrolysis effect is better than the iron-carbon separation. Conventional iron-carbon micro-electrolysis is to separate iron from carbon. Such iron is easy to rust due to long-term contact with water during the use of wetlands, causing hardening and blocking artificial wetlands. Sponge iron and activated carbon are mixed in a certain proportion to form micro-electrolysis balls, which have the advantages of rough surface, more holes, and large specific surface area, and can form abundant and large iron-carbon micro-electrolysis cells to promote sewage treatment effects.

[0018] Iron and carbon materials form a micro-electrolysis reaction, which will be gradually consumed during use. Since they are embedded in non-degradable plastic, the process will be relatively slow, and the environment around ammonia oxidizing bacteria will be slightly alkaline, rather than over-alkaline. 2+ It is also appropriate, and will not cause excessive waste. The other components of the rope-shaped artificial water plants loaded with iron-carbon micro-electrolysis balls will not be consumed over time, so the overall durability is strong and can play a role for a long time;

[0019] With the action of water flow, corn cob powder gradually dissolves, releasing a small amount of activated carbon source, which enhances the biological affinity of the rope-shaped artificial water grass loaded with iron-carbon micro-electrolysis balls. At the same time, the reserved pore structure increases the specific surface area of ​​the iron-carbon micro-electrolysis balls, allowing them to fully contact with sewage and form more iron-carbon micro-electrolysis cells.

[0020] Furthermore, the volume ratio of sponge iron, activated carbon, non-degradable plastic and pore-forming material is (15-20): (5-10): (10-15): (1-3), the non-degradable plastic is polycarbonate resin, and the pore-forming material is corn cob powder.

[0021] The further beneficial effects of adopting the above are: the reason for selecting this ratio is that sponge iron, as a reaction material, will be gradually consumed, so its proportion should be appropriately increased; non-degradable plastic is the main supporting material, and if the proportion is too low, it will be difficult to wrap other materials into iron-carbon balls; the pore-forming material will be gradually consumed in the early stage of the reaction to leave more pore structures and increase the specific surface area, and the proportion should not be too large.

[0022] Furthermore, ammonia oxidizing bacteria are embedded in the iron-carbon micro-electrolysis sphere.

[0023] The above method has the further beneficial effect of increasing the density and stability of ammonia oxidizing bacteria on the biological carrier.

[0024] Furthermore, the rope-shaped artificial aquatic plant includes: a central bag, which is a dense plastic hollow net bag, flexible fluffy fibers are fixed outside the central bag, and iron-carbon micro-electrolysis balls are placed in the central bag, and the particle size of the iron-carbon micro-electrolysis balls is 10mm to 15mm.

[0025] The above-mentioned further beneficial effects are: placing the iron-carbon micro-electrolysis balls into the central bag of the rope-shaped artificial aquatic plants is easy to operate, and the slightly alkaline environment and ferrous ions produced by the iron-carbon micro-electrolysis can be easily utilized by the ammonia oxidizing bacteria around them, greatly improving the utilization efficiency of the iron-carbon micro-electrolysis materials. In addition, even if the iron-carbon micro-electrolysis balls produce some rust, due to the filtering effect of the central bag, it will not flow into the wetland to cause blockage, which is efficient, green and pollution-free.

[0026] Furthermore, the filler layer matrix of the downward subsurface flow artificial wetland is limestone and gravel, and the volume mixing ratio of limestone and gravel is 1: (1-10).

[0027] A further beneficial effect of the above is that limestone can also create a slightly alkaline environment, which is more conducive to the growth and reproduction of ammonia oxidizing bacteria.

[0028] Furthermore, the density of the artificial water grass is 5 to 13 ropes / m. 2 .

[0029] The above further beneficial effect is that the density range has a good synergistic removal effect on sulfamethoxazole and total nitrogen, and the investment cost is low.

[0030] Furthermore, an elbow for raising the outlet water level is connected to the drainage main pipe of the downward submerged flow artificial wetland, and the elbow connected to the drainage main pipe of the downward submerged flow artificial wetland is so that the unsaturated zone accounts for 33% to 50%.

[0031] The above method has the further beneficial effect that the area above the elbow is an unsaturated area, and the area below the elbow is a saturated area, and the ratio of the unsaturated area to the saturated area can be defined by the elbow.

[0032] Furthermore, reeds or loosestrife are planted on the planting layer of the downward subsurface flow artificial wetland. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural diagram of a subsurface artificial wetland for efficient and synergistic removal of sulfamethoxazole and total nitrogen based on iron-carbon micro-electrolysis in the prior art;

[0034] Figure 2 This is a structural diagram of the rope-shaped artificial waterweed loaded with iron-carbon micro-electrolysis balls in the present invention;

[0035] Figure 3 It is a structural diagram of the iron-carbon micro-electrolysis ball in the present invention.

[0036] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0037] 1. Downward subsurface flow artificial wetland, 110, filler layer, 120, drainage main pipe, 2. Iron-carbon micro-electrolysis ball, 3. Rope-shaped artificial aquatic plant, 310, center bag, 320, flexible fluffy fiber, 4. Elbow. DETAILED DESCRIPTION

[0038] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0039] Example 1

[0040] like Figure 1 , Figure 2 , Figure 3 As shown, a submerged flow artificial wetland based on iron-carbon micro-electrolysis for efficient synergistic removal of sulfamethoxazole and total nitrogen comprises: a downward submerged flow artificial wetland 1, a packing layer 110 of the downward submerged flow artificial wetland 1 is composed of two layers, wherein the upper layer is an unsaturated zone, i.e., an aerobic zone, and the lower layer is a saturated zone, i.e., an anaerobic zone, and a rope-shaped artificial waterweed 3 loaded with iron-carbon micro-electrolysis balls 2 is arranged between the unsaturated zone and the saturated zone distributed upward and downward along the water flow direction in the packing layer 110 of the downward submerged flow artificial wetland 1;

[0041] Under aerobic conditions, the iron-carbon micro-electrolysis balls loaded on the rope-like artificial water plants undergo micro-electrolysis reactions, thereby releasing ferrous ions (Fe 2+ ) and alkaline substances, while alkaline substances, Fe 2+ The alkaline substances are quickly and effectively transmitted to the ammonia oxidizing bacteria enriched on the rope-shaped artificial water plants. The weakly alkaline environment created by the alkaline substances creates suitable environmental conditions for the growth and reproduction of ammonia oxidizing bacteria that can effectively reduce total nitrogen and sulfamethoxazole, thereby increasing the abundance of ammonia oxidizing bacteria and Fe 2+It can promote the secretion of extracellular polymers of ammonia oxidizing bacteria and the synthesis of heme C, which can greatly stimulate the activity of ammonia oxidizing bacteria. Through cooperation, it can effectively improve the removal rate of total nitrogen and sulfamethoxazole that rely on the action of ammonia oxidizing bacteria for degradation and metabolism, and the removal rate is above 90%. The whole process is mainly the reduction of pollutants by microorganisms, no pollutants are generated, and no negative impact on wetland clogging will be caused;

[0042] In an anaerobic environment, the products produced by iron-carbon micro-electrolysis itself (such as [H], i.e., active hydrogen ions) are highly active and can not only remove some difficult-to-degrade substances, such as heavy metals, but also change the form and structure of some organic matter and improve the biodegradability of water bodies. In addition, the electrons produced by iron-carbon micro-electrolysis are conducive to the reduction of pollutants.

[0043] In addition, metallic iron can also undergo a replacement reaction with heavy metal ions that rank after iron in the metal activity order in wastewater, and has a good removal effect on some heavy metals;

[0044] The rope-shaped artificial water grass arranged in the packing layer has the following functions: it can prolong the flow of water in the unsaturated zone, increase the contact time between microorganisms, iron-carbon balls and sewage; provide a very suitable growth and reproduction environment for the growth of ammonia oxidizing bacteria; it can play a role in heat preservation and insulation, and provide a suitable and good temperature environment for ammonia oxidizing bacteria as much as possible;

[0045] The iron-carbon micro-electrolysis balls are loaded onto rope-shaped artificial aquatic plants. When the artificial wetland fillers are filled, they can be placed according to the set partition ratio. The operation is simple. Both the iron-carbon micro-electrolysis balls and the rope-shaped artificial aquatic plants are relatively cheap and easy to obtain. Combining them together can maximize the potential and utilization rate of the materials, and the cost performance is extremely high.

[0046] Example 2

[0047] like Figure 1 As shown, this embodiment is a further improvement on the basis of embodiment 1, and the details are as follows:

[0048] The ratio of the rope-shaped artificial aquatic plants 3 placed in the unsaturated zone and the saturated zone is 1:1 to 1:2. Both aerobic ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria have a certain removal effect on sulfamethoxazole and total nitrogen. Relatively speaking, aerobic ammonia oxidizing bacteria can better improve the removal effect of sulfamethoxazole, while anaerobic ammonia oxidizing bacteria can better improve the removal rate of total nitrogen. Selecting this ratio can make the removal rates of sulfamethoxazole and total nitrogen higher.

[0049] Example 3

[0050] like Figure 2 , Figure 3 As shown, this embodiment is a further improvement on the basis of Embodiment 1 or 2, and the details are as follows:

[0051] The materials of the iron-carbon micro-electrolysis ball 2 are: sponge iron, activated carbon, non-degradable plastic and pore-forming material, which are processed by melt blending process, and the heating temperature is 160℃~250℃;

[0052] The effect of iron-carbon integrated micro-electrolysis is better than that of iron-carbon separation. Conventional iron-carbon micro-electrolysis separates iron from carbon. Such iron is prone to rust due to long-term contact with water during the use of wetlands, causing compaction and clogging of artificial wetlands. Sponge iron and activated carbon are mixed in a certain proportion into micro-electrolysis balls, which have the advantages of rough surface, more pores, and large specific surface area. They can also form abundant and large numbers of iron-carbon micro-electrolysis cells to promote sewage treatment effects.

[0053] Figure 3 This is the structural diagram of the iron-carbon micro-electrolysis ball, where the black balls represent the iron-carbon balls, the triangles represent the pore-forming materials, and the gray area represents the non-degradable plastic.

[0054] Furthermore: the volume ratio of sponge iron, activated carbon, non-degradable plastic and pore-forming material is (15-20): (5-10): (10-15): (1-3). In this embodiment: the non-degradable plastic is preferably polycarbonate resin, and the pore-forming material is preferably corn cob powder. With the action of water flow, the corn cob powder is gradually dissolved, releasing a small amount of activated carbon source, thereby enhancing the bioaffinity of the rope-shaped artificial aquatic plant 3 loaded with the iron-carbon micro-electrolysis ball 2. At the same time, the reserved pore structure increases the specific surface area of ​​the iron-carbon micro-electrolysis ball 2, allowing it to fully contact with the sewage to form more iron-carbon micro-electrolysis cells. The reason for selecting this ratio is that sponge iron, as a reaction material, will be gradually consumed, so its proportion should be appropriately increased. Non-degradable plastic is the main supporting material, and if the proportion is too low, it is difficult to wrap other materials into iron-carbon balls. The pore-forming material will be gradually consumed in the early stage of the reaction to leave more pore structures and increase the specific surface area. The proportion should not be too large.

[0055] Example 4

[0056] like Figure 2 , Figure 3 As shown, this embodiment is a further improvement on the basis of Embodiment 1, 2 or 3, and the details are as follows:

[0057] Ammonia oxidizing bacteria are embedded in the iron-carbon micro-electrolysis ball 2 to increase the density and stability of ammonia oxidizing bacteria on the biological carrier.

[0058] Example 5

[0059] like Figure 2 As shown, this embodiment is a further improvement on the basis of Embodiment 1, 2, 3 or 4, and the details are as follows:

[0060] The rope-shaped artificial aquatic plant 3 includes: a central bag 310, which is a dense plastic hollow net bag. Flexible fluffy fibers 320 are fixed outside the central bag 310. The flexible fluffy fibers 320 can be made of chemical fiber materials such as polyester fiber, vinylon, and polyester, and have good water conductivity and biological affinity. The iron-carbon micro-electrolysis ball 2 is placed in the central bag 310, so that the slightly alkaline environment and ferrous ions produced by the iron-carbon micro-electrolysis can be easily utilized by the ammonia oxidizing bacteria around it, which greatly improves the utilization efficiency of the iron-carbon micro-electrolysis material. The particle size of the iron-carbon micro-electrolysis ball 2 is 10mm~15mm.

[0061] Example 6

[0062] like Figure 1 As shown, this embodiment is a further improvement on any one of Embodiments 1 to 5, and the details are as follows:

[0063] The matrix of the filler layer 110 of the downward subsurface flow artificial wetland 1 is limestone and gravel, and the volume mixing ratio of limestone and gravel is 1: (1-10). Limestone can also create a slightly alkaline environment, which is more conducive to the growth and reproduction of ammonia oxidizing bacteria.

[0064] Example 7

[0065] like Figure 1 As shown, this embodiment is a further improvement on any one of Embodiments 1 to 6, and the details are as follows:

[0066] The laying density of the rope-shaped artificial water plants 3 is preferably 5 to 13 strands / m 2 This density range has a good synergistic removal effect on sulfamethoxazole and total nitrogen, and the investment cost is low.

[0067] Example 8

[0068] like Figure 1 As shown, this embodiment is a further improvement on any one of Embodiments 1 to 7, and the details are as follows:

[0069] The drainage main pipe 120 of the downward submerged flow artificial wetland 1 is connected to an elbow 4 for raising the outlet water level. The drainage main pipe 120 of the downward submerged flow artificial wetland 1 is connected to the elbow 4 so that the unsaturated zone accounts for 33% to 50%. The area above the elbow 4 is the unsaturated zone, and the area below the elbow 4 is the saturated zone. The ratio of the unsaturated zone to the saturated zone can be defined by the elbow 4.

[0070] Example 9

[0071] like Figure 1 As shown, this embodiment is a further improvement on any one of Embodiments 1 to 8, and the details are as follows:

[0072] Aquatic plants that are drought-tolerant and alkaline-tolerant, such as reeds or loosestrife, are planted on the planting layer of the downward subsurface flow artificial wetland 1.

[0073] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A subsurface constructed wetland based on iron-carbon micro-electrolysis for efficient and synergistic removal of sulfamethoxazole and total nitrogen, characterized in that: include: A downward subsurface flow artificial wetland (1), wherein a drain main pipe (120) at the bottom of the downward subsurface flow artificial wetland (1) is connected to an elbow (4) for raising the outlet water level, the area above the elbow (4) is an unsaturated area, and the area below the elbow (4) is a saturated area, the drain main pipe (120) of the downward subsurface flow artificial wetland (1) is connected to the elbow (4) so ​​that the unsaturated area of ​​the filler layer (110) accounts for 33% to 50%, and rope-shaped artificial water grass (2) loaded with iron-carbon micro-electrolysis balls (2) is arranged between the unsaturated area and the saturated area distributed upward and downward along the water flow direction in the filler layer (110) of the downward subsurface flow artificial wetland (1). 3), the rope-shaped artificial water grass (3) is placed in the unsaturated zone and the saturated zone in a ratio of 1: (1-2), the rope-shaped artificial water grass (3) comprises: a central bag (310), the central bag (310) is a dense plastic hollow net bag, a flexible fluffy fiber (320) is fixed outside the central bag (310), the iron-carbon micro-electrolysis ball (2) is placed in the central bag (310), the particle size of the iron-carbon micro-electrolysis ball (2) is 10 mm to 15 mm, and under aerobic conditions in the unsaturated zone, the iron-carbon micro-electrolysis ball (2) loaded on the rope-shaped artificial water grass (3) undergoes a micro-electrolysis reaction to release Fe into the wetland. 2+ The weak alkaline environment created by alkaline substances provides a suitable environment for the growth and reproduction of ammonia oxidizing bacteria. 2+ Promote the secretion of extracellular polymers of ammonia oxidizing bacteria and the synthesis of heme C.

2. The subsurface artificial wetland for efficient synergistic removal of sulfamethoxazole and total nitrogen based on iron-carbon micro-electrolysis according to claim 1, characterized in that: The materials of the iron-carbon micro-electrolysis ball (2) are: sponge iron, activated carbon, non-degradable plastic and pore-forming material.

3. The subsurface artificial wetland for efficient synergistic removal of sulfamethoxazole and total nitrogen based on iron-carbon micro-electrolysis according to claim 2, characterized in that: The volume ratio of the sponge iron, activated carbon, non-degradable plastic and pore-forming material is (15-20): (5-10): (10-15): (1-3), the non-degradable plastic is polycarbonate resin, and the pore-forming material is corn cob powder.

4. The subsurface artificial wetland for efficient synergistic removal of sulfamethoxazole and total nitrogen based on iron-carbon micro-electrolysis according to claim 1, characterized in that: Ammonia oxidizing bacteria are embedded in the iron-carbon micro-electrolysis ball (2).

5. The subsurface artificial wetland for efficient synergistic removal of sulfamethoxazole and total nitrogen based on iron-carbon micro-electrolysis according to claim 1, characterized in that: The matrix of the filler layer (110) of the downward subsurface flow artificial wetland (1) is limestone and crushed stone, and the volume mixing ratio of the limestone and crushed stone is 1: (1-10).

6. The subsurface artificial wetland for efficient synergistic removal of sulfamethoxazole and total nitrogen based on iron-carbon micro-electrolysis according to claim 1, characterized in that: The arrangement density of the rope-shaped artificial waterweed (3) is 5 to 13 pieces / m 2 .

7. The subsurface artificial wetland for efficient synergistic removal of sulfamethoxazole and total nitrogen based on iron-carbon micro-electrolysis according to claim 1, characterized in that: Reeds or Lythrum salicaria are planted on the planting layer of the downward subsurface flow artificial wetland (1).

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