Low-temperature biological regulation constructed wetland system for tail water of sewage plant and method for treating sewage by utilizing low-temperature biological regulation constructed wetland system

Abstract

The invention belongs to the technical field of sewage treatment systems, and particularly relates to a low-temperature biological regulation and control constructed wetland system for tail water of a sewage plant and a method for treating sewage by using the low-temperature biological regulation and control constructed wetland system for the tail water of the sewage plant, the low-temperature biological regulation and control constructed wetland system comprises a water inlet system, a constructed wetland pool body and a drainage pipeline, the water inlet system comprises a water inlet pipeline; the water inlet pipeline is laid at the bottom of the wetland filler area; the constructed wetland pool body is divided into a wetland filler area and a water collecting area by a perforated lattice wall; wetland plants are planted above the wetland filler area; a filler filled in the wetland filler area comprises hydroxyl modified graphene oxide coating volcanic rock and a non-coating filler; the drainage pipeline is located in the water collecting area. The constructed wetland system provided by the invention has good low-temperature nitrogen removal efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment systems, and in particular relates to a low-temperature biological regulation artificial wetland system for tail water of a sewage plant and a method for treating sewage using the same. Background Art

[0002] Constructed wetland technology utilizes the synergistic effects of fillers, plants, and microorganisms to remove organic matter, nitrogen, and phosphorus from wastewater through adsorption, precipitation, filtration, ion exchange, plant absorption, and microbial degradation. It has become a key technology for wastewater ecological treatment and is increasingly being applied in wastewater treatment plant tailwater upgrading and resource utilization projects. Constructed wetlands offer advantages such as effective water purification, low treatment costs, simplified operation and management, and attractive environmental and landscape effects. Their application in deep purification of wastewater treatment plant tailwater can not only address water pollution issues in receiving water bodies, but also, to a certain extent, alleviate the lack of ecological base flow and insufficient hydrodynamics in rivers.

[0003] However, during low temperatures, constructed wetlands significantly reduce their treatment efficiency because low temperatures inhibit plant and microbial activity, particularly the activity of functional microorganisms involved in nitrogen transformation, nitrification and denitrification. Therefore, low temperatures are the most significant limiting factor to the stable operation of constructed wetlands. Furthermore, commonly used protective measures during low temperatures, such as insulation, reducing hydraulic loads, and extending residence time, have been less than ideal. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-temperature biological regulation artificial wetland system for sewage plant tail water and its application. The artificial wetland system provided by the present invention has good low-temperature nitrogen removal efficiency.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a low-temperature biological regulation artificial wetland system for tail water of a sewage treatment plant, comprising a water inlet system, an artificial wetland pool and a drainage pipe;

[0007] The water inlet system includes a water inlet pipe; the water inlet pipe is laid at the bottom of the wetland filling area;

[0008] The artificial wetland pool is divided into a wetland filling area and a water collection area by a perforated flower wall; wetland plants are planted above the wetland filling area; the fillers filled in the wetland filling area include hydroxyl-modified graphene oxide-coated volcanic rocks and non-coated fillers;

[0009] The drainage pipe is located in the water collection area.

[0010] Preferably, the height between the holes in the perforated flower wall and the bottom of the artificial wetland pool is ≥100 cm.

[0011] Preferably, the non-coated filler includes one or more of rock fragments, bioceramsite and zeolite; the rock fragments include gravel or crushed stone.

[0012] Preferably, the preparation of the hydroxyl-modified graphene oxide comprises the following steps:

[0013] mixing a dispersion of graphene oxide and a NaOH solution to perform hydroxylation to obtain hydroxylated graphene oxide;

[0014] mixing the hydroxylated graphene oxide and thionyl chloride, and performing a chlorination reaction to obtain chlorinated graphene oxide;

[0015] The chlorinated graphene oxide, polyethylene glycol and pyridine are mixed and modified to obtain hydroxyl-modified graphene oxide.

[0016] Preferably, the preparation of the hydroxyl-modified graphene oxide coating volcanic rock comprises the following steps:

[0017] After activating the volcanic rock, the volcanic rock is immersed in a dispersion of hydroxyl-modified graphene oxide to load the hydroxyl-modified graphene oxide, thereby obtaining a volcanic rock with the hydroxyl-modified graphene oxide loaded on its surface;

[0018] The volcanic rock with the hydroxyl-modified graphene oxide loaded on the surface is mixed with an APTES ethanol solution to obtain the hydroxyl-modified graphene oxide-coated volcanic rock.

[0019] Preferably, the drainage pipe is a water level regulating drainage pipe; the water level regulating drainage pipe is a drainage pipe provided with a rotary elbow.

[0020] Preferably, the rotating elbow portion is located in the water collection area, and the other end passes through the side wall of the pool body.

[0021] Preferably, measured from the bottom of the artificial wetland pool, the modified graphene oxide coating filler is located in an effective depth area of ​​60 cm to 150 cm from the bottom of the pool.

[0022] Preferably, the hydroxyl-modified graphene oxide coating filler accounts for 10 to 50% of the total filler volume.

[0023] The present invention also provides a method for treating sewage using the sewage plant tail water low-temperature biological regulation artificial wetland system described in the above technical solution, comprising the following steps:

[0024] The tail water of the sewage treatment plant is introduced from the water inlet pipe into the wetland filler area of ​​the artificial wetland pool for purification. The purified water flows into the catchment area through the perforated flower wall and is then discharged through the drainage pipe.

[0025] The present invention provides a low-temperature biological regulation artificial wetland system for tail water of a sewage treatment plant, comprising a water inlet system, an artificial wetland pool body and a drainage pipe; the water inlet system comprises a water inlet pipe; the water inlet pipe is laid at the bottom of the wetland filling area; the artificial wetland pool body is divided into a wetland filling area and a water collection area by a perforated flower wall; wetland plants are planted above the wetland filling area; the filler filled in the wetland filling area comprises hydroxyl-modified graphene oxide-coated volcanic rock and non-coated filler; the drainage pipe is located in the water collection area.

[0026] The artificial wetland system provided by the present invention has the following advantages:

[0027] (1) The artificial wetland system provided by the present invention uses hydroxyl-modified graphene oxide-coated volcanic rock. This filler has higher pollutant adsorption performance and microbial affinity, which can improve the abundance of functional microorganisms in the artificial wetland.

[0028] (2) The hydroxyl-modified graphene oxide-coated volcanic rock used in the present invention can stimulate the aggregation performance of extracellular polymers (EPS) at low temperatures, forming denser and more stable microbial aggregates, increasing tightly bound EPS, and reducing dissolved and loose EPS, forming denser and more stable microbial aggregates, improving the ability of functional organisms to resist low-temperature environments, and enhancing the activity of functional microorganisms.

[0029] (3) At low temperatures, hydroxyl-modified graphene oxide-coated volcanic rocks can enhance the electrochemical activity of EPS, improve the extracellular electron transfer efficiency of microorganisms, promote the microbial denitrification process under low temperature conditions, and improve the low-temperature denitrification efficiency;

[0030] (4) The wetland filler of the present invention can regulate the adaptability and denitrification process of functional microorganisms in the low temperature period, and can be added once. The functional microorganisms can be automatically regulated according to the temperature in the later stage without the need for further operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 Schematic diagram of the artificial wetland system provided by the present invention, wherein 1-wetland filler area, 2-hydroxy-modified graphene oxide-coated volcanic rock, 3-wetland plants, 4-perforated flower wall, 5-water collection area, 6-drainage pipe, and 7-water inlet system. DETAILED DESCRIPTION

[0033] The present invention provides a low-temperature biological regulation artificial wetland system for tail water of a sewage treatment plant, comprising a water inlet system, an artificial wetland pool and a drainage pipe;

[0034] The water inlet system includes a water inlet pipe; the water inlet pipe is laid at the bottom of the wetland filling area;

[0035] The artificial wetland pool is divided into a wetland filling area and a water collection area by a perforated flower wall; wetland plants are planted above the wetland filling area; the filler filled in the wetland filling area includes hydroxyl-modified graphene oxide coated volcanic rock and non-coated filler; the drainage pipe is located in the water collection area.

[0036] The artificial wetland system provided by the present invention includes a water inlet system.

[0037] As one embodiment of the present invention, the water inlet system includes a water inlet pipe; the nominal diameter of the water inlet pipe is preferably 100 mm; preferably, the water inlet system includes a water inlet pipe and a sewage lift pump. In the present invention, the water inlet system preferably utilizes a sewage lift pump to lift or gravity-flow water through the water inlet pipe for uniform distribution. As one embodiment of the present invention, the water inlet pipe is preferably laid below the permafrost layer, at the bottom of the wetland fill area. In the present invention, laying the water inlet pipe below the permafrost layer can reduce the loss of inlet water temperature.

[0038] The artificial wetland system provided by the present invention comprises an artificial wetland pool body; the artificial wetland pool body is divided into a wetland filling area and a water collection area by a perforated flower wall; wetland plants are planted above the wetland filling area.

[0039] As an embodiment of the present invention, the height of the holes in the perforated flower wall from the bottom of the artificial wetland pool is preferably ≥100 cm; as an embodiment of the present invention, the wetland plants are preferably native wetland plants with well-developed root systems, specifically yellow iris and / or loosestrife.

[0040] As an embodiment of the present invention, the filler includes hydroxyl-modified graphene oxide-coated volcanic rock and non-coated filler.

[0041] As an embodiment of the present invention, the non-coated filler preferably includes one or more of rock fragments, bioceramsite and zeolite; the rock fragments preferably include gravel or crushed stone.

[0042] As an embodiment of the present invention, the particle size of the hydroxyl-modified graphene oxide coated volcanic rock is preferably 10 to 30 mm; the particle size of the crushed stone is preferably 5 to 20 mm; the particle size of the gravel is preferably 20 to 40 mm; the particle size of the bioceramsite is preferably 10 to 30 mm; and the particle size of the zeolite is preferably 20 to 30 mm.

[0043] As an embodiment of the present invention, the preparation of the hydroxyl-modified graphene oxide comprises the following steps:

[0044] mixing a dispersion of graphene oxide and a NaOH solution to perform hydroxylation to obtain hydroxylated graphene oxide;

[0045] mixing the hydroxylated graphene oxide and thionyl chloride, and performing a chlorination reaction to obtain chlorinated graphene oxide;

[0046] The chlorinated graphene oxide, polyethylene glycol and pyridine are mixed and modified to obtain hydroxyl-modified graphene oxide.

[0047] As an embodiment of the present invention, the concentration of the graphene oxide dispersion may be 1 g / L, and the graphene dispersion may be prepared by the Hummers method.

[0048] As an embodiment of the present invention, the concentration of the NaOH solution can be 1.0-2.0M; the volume ratio of the NaOH solution to the graphene oxide dispersion is preferably 1:1; as an embodiment of the present invention, the temperature of the hydroxylation is preferably 80°C, and the time is preferably 4 hours. As an embodiment of the present invention, after the hydroxylation, the hydroxylation system is subjected to centrifugal washing and dialysis in sequence; the centrifugal washing is preferably washed to neutrality; the dialysis bag has a molecular weight cutoff of 23Da; the dialysis time is preferably 36 hours, and after the dialysis, the dialysate is discarded and the residue is freeze-dried to obtain hydroxylated graphene.

[0049] As an embodiment of the present invention, the ratio of the hydroxylated graphene oxide to thionyl chloride is preferably 100 mg: 2 mL. As an embodiment of the present invention, the temperature of the chlorination reaction is preferably 70° C., and the time is preferably 6 hours.

[0050] In one embodiment of the present invention, the weight-average molecular weight of the polyethylene glycol is 2000; the mass ratio of the hydroxylated graphene to the polyethylene glycol is preferably 0.1:2; and the amount ratio of the polyethylene glycol to pyridine is preferably 2 g:0.1 mL. In one embodiment of the present invention, the modification is preferably performed under a protective atmosphere, which may be nitrogen. In one embodiment of the present invention, the modification temperature is preferably 110°C, and the modification time is preferably 24 hours.

[0051] As an embodiment of the present invention, after the modification, the process further comprises dialyzing the modified system to remove free polyethylene glycol, and freeze-drying the residue to obtain the hydroxyl-modified graphene oxide.

[0052] As an embodiment of the present invention, the preparation of the hydroxyl-modified graphene oxide-coated volcanic rock comprises the following steps:

[0053] After activating the volcanic rock, the volcanic rock is immersed in a dispersion of hydroxyl-modified graphene oxide to load the hydroxyl-modified graphene oxide, thereby obtaining a volcanic rock with the hydroxyl-modified graphene oxide loaded on its surface;

[0054] The volcanic rock with the hydroxyl-modified graphene oxide loaded on the surface is mixed with an APTES ethanol solution to obtain the hydroxyl-modified graphene oxide-coated volcanic rock.

[0055] As an embodiment of the present invention, the particle size of the volcanic rock is preferably 2 to 5 mm. As an embodiment of the present invention, the activation comprises acidification and oxidation performed sequentially.

[0056] As an embodiment of the present invention, the acidifying agent is preferably hydrochloric acid; the mass concentration of the hydrochloric acid is preferably 5%, and the acidifying time is preferably 24 hours; the oxidation is preferably soaking the acidified volcanic rock in a H2O2 solution and ultrasonicating; the mass concentration of the H2O2 solution is preferably 30%; the ultrasonication time is preferably 1 hour; after the oxidation, the oxidized volcanic rock is further dried.

[0057] As an embodiment of the present invention, the dispersion of hydroxyl-modified graphene oxide includes modified graphene oxide, ethanol and water; the volume ratio of ethanol to water is preferably 1:1, and the concentration of the dispersion of hydroxyl-modified graphene oxide is preferably 2 g / L.

[0058] As an embodiment of the present invention, the impregnation is preferably vacuum impregnation and ultrasonic-assisted impregnation performed sequentially; the pressure of the vacuum impregnation is preferably -0.1 MPa, and the time is preferably 2 hours; the ultrasonic frequency of the ultrasonic-assisted impregnation is preferably 40 Khz, and the time is preferably 30 minutes; after the impregnation, it is preferably also included to remove excess solution and dry the product; the drying is preferably vacuum drying; the temperature of the vacuum drying is preferably 60°C, and the time is preferably 12 hours.

[0059] As one embodiment of the present invention, the mass concentration of the APTES ethanol solution is preferably 1%. As one embodiment of the present invention, the volcanic rock with the hydroxyl-modified graphene oxide on its surface and the APTES ethanol solution are preferably mixed for 1 hour. After the soaking, the process preferably further includes removing excess solution from the soaking system and drying to obtain the hydroxyl-modified graphene oxide-coated volcanic rock.

[0060] As an embodiment of the present invention, the effective depth of the wetland filler area is 120 to 180 cm; measured from the bottom of the artificial wetland pool, the hydroxyl-modified graphene oxide coating filler is located in an effective depth area of ​​60 to 150 cm from the bottom of the pool; the hydroxyl-modified graphene oxide coating filler preferably accounts for 10 to 50% of the total filler volume.

[0061] The artificial wetland system provided by the present invention comprises a drainage pipe located in the water collection area.

[0062] In one embodiment of the present invention, the drainage pipe comprises a water level regulating drainage pipe; the water level regulating drainage pipe is preferably a drainage pipe equipped with a swivel elbow; the swivel elbow portion is located in the water collection area, and the other end passes through the side wall of the artificial wetland. In one embodiment of the present invention, the water level regulating drainage pipe preferably has a nominal diameter of 150 mm.

[0063] The present invention also provides a method for regulating an artificial wetland system using low-temperature organisms in sewage plant tail water according to the above technical solution, comprising the following steps:

[0064] The tail water of the sewage treatment plant is introduced from the water inlet pipe into the wetland filler area of ​​the artificial wetland pool for purification. The purified water flows into the catchment area through the perforated flower wall and is then discharged through the drainage pipe.

[0065] In the present invention, when the tail water flows through the functional filler in the low-temperature period, the hydroxyl-modified graphene oxide-coated volcanic rock can stimulate the aggregation performance of extracellular polymers (EPS) at low temperatures, increase the tightly bound EPS, reduce the dissolved and loose EPS, form more compact and stable microbial aggregates, and enhance the ability of functional organisms to resist low-temperature environments. At the same time, the hydroxyl-modified graphene oxide-coated volcanic rock at low temperatures enhances the electrochemical activity of EPS, improves the extracellular electron transfer efficiency of microorganisms, promotes the microbial denitrification process in low-temperature environments, and effectively solves the problem of low pollutant degradation efficiency in the low-temperature period.

[0066] In order to further illustrate the present invention, the scheme of the present invention is described in detail below with reference to the accompanying drawings and embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0067] Example 1

[0068] Preparation of hydroxyl-modified graphene oxide:

[0069] A 1 g / L graphene oxide dispersion (prepared by the Hummers method) and a 1.0 M NaOH solution were mixed (the volume ratio of the graphene oxide dispersion to the NaOH solution was 1:1), and hydroxylation was performed (temperature was 80° C., time was 4 h), and then the hydroxylated system was centrifuged and dialyzed in sequence; the centrifugal washing was preferably washed to neutrality; the dialysis bag had a molecular weight cutoff of 23 Da; the dialysis time was 36 h, the dialyzate was discarded after the dialysis, and the residue was freeze-dried to obtain hydroxylated graphene oxide;

[0070] 100 mg of hydroxylated graphene oxide was mixed with 2 mL of thionyl chloride and subjected to chlorination reaction at 70 °C for 6 h to obtain chlorinated graphene oxide;

[0071] The chlorinated graphene oxide, 2 g of polyethylene glycol-2000 and 0.1 mL of pyridine were mixed and modified under a nitrogen atmosphere (temperature of 110° C. for 24 h). The modified system was then dialyzed to remove free polyethylene glycol, and the residue was freeze-dried to obtain the hydroxyl-modified graphene oxide.

[0072] The volcanic rock with a thickness of 2 to 5 mm was immersed in 5% hydrochloric acid for acidification, and then the acidified volcanic rock was immersed in 30% hydrogen peroxide for ultrasonication, and then the ultrasonicated volcanic rock was dried to obtain activated volcanic rock; the cremated volcanic rock was immersed in 2 g / L hydroxyl-modified graphene oxide dispersion (the dispersion of hydroxyl-modified graphene oxide comprises modified graphene oxide, ethanol and water; the volume ratio of ethanol to water is 1:1), and the hydroxyl-modified graphene oxide was loaded (vacuum impregnation and ultrasonic-assisted impregnation were performed in sequence). ; the vacuum impregnation pressure is -0.1MPa, and the time is 2h; the ultrasonic frequency of the ultrasonic-assisted impregnation is 40Khz, and the time is 30min), then the excess solution is removed, and the product is vacuum dried (the vacuum drying temperature is 60°C, and the time is 12h) to obtain volcanic rock loaded with hydroxyl-modified graphene oxide; after mixing the volcanic rock with hydroxyl-modified graphene oxide on the surface and a 1% APTES ethanol solution with a mass concentration for 1h, the excess solution of the immersion system is removed and dried to obtain volcanic rock with a hydroxyl-modified graphene oxide coating.

[0073] See Figure 1The artificial wetland system includes an artificial wetland pool, wetland fillers, wetland plants, a water inlet system, and a drainage pipe. The size of the wetland pool is 0.5m×0.3m×1.5m, and the effective depth of the wetland filler is 120cm. The wetland filler is composed of hydroxyl-modified graphene oxide-coated volcanic rock, gravel, and bioceramic aggregate, with a composition ratio (volume ratio) of 3:5:2. The filler distribution (from bottom to top) is gravel and bioceramic aggregate (3:1) (30cm); hydroxyl-modified graphene oxide-coated volcanic rock, gravel, and bioceramic aggregate (3:5:2) (effective depth of 70cm); gravel (effective depth of 20cm); the wetland plant yellow iris is planted on the filler; the drainage pipe is a drainage pipe equipped with a rotary elbow. The water inlet system uses a sewage lift pump to lift sewage to the artificial wetland pool.

[0074] The temperature of the wastewater treatment plant tailwater was 8.3-10.5°C, and the main pollutants COD, ammonia nitrogen, total nitrogen, and total phosphorus contained were 45.24±3.78 mg / L, 1.50±0.45 mg / L, 12.35±2.16 mg / L, and 0.40±0.09 mg / L, respectively;

[0075] The sewage treatment plant tailwater is pumped to the fill area of ​​the constructed wetland tank for purification with a hydraulic retention time of 48 hours. After passing through the constructed wetland system, the effluent temperature is 8.2-9.4°C, and the main pollutants in the effluent are 16.02±0.97mg / L, 0.56±0.22mg / L, 6.78±0.32mg / L, and 0.18±0.12mg / L, respectively.

[0076] Comparative Example 1

[0077] The only difference from Example 1 is that the hydroxyl-modified graphene oxide-coated volcanic rock is replaced by volcanic rock, and the rest remains unchanged.

[0078] After detecting the water pollutants and comparing them with Example 1, it was found that the average removal rates of the main pollutants COD, ammonia nitrogen, total nitrogen and total phosphorus in Example 1 were increased by 18.64%, 24.31%, 35.82% and 9.15%, respectively.

[0079] The present invention also tests the EPS concentration in Example 1 and Comparative Example 1. The microbial EPS is extracted step by step using a thermal extraction method (refer to Liu, H., & Fang, HHP (2002). Extraction of extracellular polymeric substances (EPS) from sludges using cation exchange resin. Journal of Biotechnology, 95(3), 249-256). The humic acid content is determined using a modified Lowry method (Frolund, B., Palmgren, R., Keiding, K., & Nielsen, PH Extraction of extracellular polymers from activated sludge using acation exchange resin. Water Research, 30(8), 1749-1758.). The test results show that the concentration of tightly bound EPS in the artificial wetland system of Example 1 is more than doubled compared with the artificial wetland with volcanic rock (no coating), and the ratio of tightly bound EPS to loosely bound EPS increases from 0.6 to more than 2.7, which significantly increases the agglomeration performance of EPS. Meanwhile, the contents of humic acid and fulvic acid increased in the tightly bound EPS compared with the loosely bound EPS in this system, indicating enhanced microbial activity.

[0080] Example 2

[0081] The artificial wetland system includes an artificial wetland pool, wetland fillers, wetland plants, a water inlet system, and a drainage pipe. The wetland pool is 30m×30m×1.5m, and the effective depth of the wetland filler is 130cm. The wetland filler is composed of hydroxyl-modified graphene oxide-coated volcanic rock, gravel, zeolite, and bioceramsite, with a composition ratio (volume ratio) of 1:4:2:3. Wetland plants such as yellow iris and loosestrife are planted on the filler. The drainage pipe is a DN150 drainage pipe equipped with a swivel elbow. The water inlet system uses a sewage lift pump for lifting, and the water inlet pipe entering the wetland unit is DN100.

[0082] During winter operation, the water temperature of the sewage treatment plant's tailwater is 7.2-11.3°C, and the main pollutants contained in it are COD, ammonia nitrogen, total nitrogen and total phosphorus, which are 44-56 mg / L, 0.92-1.48 mg / L, 9.15-17.18 mg / L and 0.42-0.45 mg / L respectively.

[0083] The sewage treatment plant tailwater is pumped to the fill area of ​​the constructed wetland tank for purification with a hydraulic retention time of 48 hours. After passing through the constructed wetland system, the effluent temperature is 8.2-9.4°C, and the main pollutants in the effluent are 32-38 mg / L of COD, 0.65-1.14 mg / L of ammonia nitrogen, 5.38-9.81 mg / L of total nitrogen, and 0.25-0.29 mg / L of total phosphorus.

[0084] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A low-temperature biological regulation artificial wetland system for sewage treatment plant tail water, characterized in that: Including water inlet system, artificial wetland pool and drainage pipes; The water inlet system includes a water inlet pipe; the water inlet pipe is laid at the bottom of the wetland filling area; The artificial wetland pool is divided into a wetland filling area and a water collection area by a perforated flower wall; wetland plants are planted above the wetland filling area; the filler filled in the wetland filling area includes hydroxyl-modified graphene oxide coated volcanic rock and non-coated filler; the drainage pipe is located in the water collection area.

2. The low-temperature biological regulation artificial wetland system for sewage treatment plant tail water according to claim 1, characterized in that: The height between the holes in the perforated flower wall and the bottom of the artificial wetland pool is ≥100 cm.

3. The low-temperature biological regulation artificial wetland system for sewage treatment plant tail water according to claim 1, characterized in that: The non-coating filler includes one or more of rock fragments, bioceramsite and zeolite; the rock fragments include gravel or crushed stone.

4. The low-temperature biological regulation artificial wetland system for sewage treatment plant tail water according to claim 1, characterized in that: The preparation of the hydroxyl-modified graphene oxide comprises the following steps: mixing a dispersion of graphene oxide and a NaOH solution to perform hydroxylation to obtain hydroxylated graphene oxide; mixing the hydroxylated graphene oxide and thionyl chloride, and performing a chlorination reaction to obtain chlorinated graphene oxide; The chlorinated graphene oxide, polyethylene glycol and pyridine are mixed and modified to obtain hydroxyl-modified graphene oxide.

5. The artificial wetland system according to claim 1, wherein: The preparation of the hydroxyl-modified graphene oxide coating volcanic rock comprises the following steps: After activating the volcanic rock, the volcanic rock is immersed in a dispersion of hydroxyl-modified graphene oxide to load the hydroxyl-modified graphene oxide, thereby obtaining a volcanic rock with the hydroxyl-modified graphene oxide loaded on its surface; The volcanic rock with the hydroxyl-modified graphene oxide loaded on the surface is mixed with an APTES ethanol solution to obtain the hydroxyl-modified graphene oxide-coated volcanic rock.

6. The low-temperature biological regulation artificial wetland system for sewage treatment plant tail water according to claim 1, characterized in that: The drainage pipe is a water level regulating drainage pipe; the water level regulating drainage pipe is a drainage pipe provided with a rotating elbow.

7. The low-temperature biological regulation artificial wetland system for sewage treatment plant tail water according to claim 6, characterized in that: The rotating elbow portion is located in the water collection area, and the other end passes through the side wall of the pool body.

8. The low-temperature biological regulation artificial wetland system for sewage treatment plant tail water according to claim 1, characterized in that: Measured from the bottom of the artificial wetland pool, the modified graphene oxide coating filler is located in an effective depth area of ​​60 cm to 150 cm from the bottom of the pool.

9. The artificial wetland system according to claim 1, wherein: The hydroxyl modified graphene oxide coating filler accounts for 10 to 50% of the volume of the entire filler.

10. A method for treating sewage using the low-temperature biologically controlled artificial wetland system for sewage plant tail water according to any one of claims 1 to 9, comprising the following steps: The tail water of the sewage treatment plant is introduced from the water inlet pipe into the wetland filler area of ​​the artificial wetland pool for purification. The purified water flows into the catchment area through the perforated flower wall and is then discharged through the drainage pipe.

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