A device and method for treating tail water by layered adsorption-artificial wetland cooperation

Abstract

The application discloses a layered adsorption-artificial wetland collaborative treatment device and method for tail water, and the device comprises a layered selective adsorption treatment unit, a pyrolysis treatment unit and a reinforced artificial wetland unit; the treatment method comprises the following steps: simulated wastewater enters the layered selective adsorption treatment unit to remove antibiotics and reduce the inhibition on denitrifying bacteria, and effluent enters the reinforced artificial wetland unit; the adsorption layer enters the pyrolysis treatment unit through one side of the parallel inclined flow guide groove, and effluent after adsorption enters the wetland unit, the salt-tolerant bacteria in the wetland play a denitrification function, and the biochar layer provides a carbon source, so that nitrogen is effectively removed; the application arranges materials with selective adsorption performance in layers, and sequentially adsorbs different categories of antibiotics; then, the effluent is treated by using the reinforced artificial wetland, so that the nutrient salt load such as nitrate nitrogen is further reduced; the microbial structure in the wetland is stable, the denitrification function of the salt-tolerant bacteria is combined, the interference of salinity on the denitrification of the wetland is reinforced, and the denitrification efficiency is significantly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, in particular to a device and method for layered adsorption-artificial wetland collaborative treatment of tail water. BACKGROUND

[0002] In the northwest region, water resources are scarce, evaporation is several dozen times higher than rainfall, and water shortage is a serious problem. In order to alleviate water shortage, ecological water replenishment of reclaimed water has become an important way to alleviate water shortage, and after replenishment, the downstream is still directly used for surrounding farmland irrigation.

[0003] However, the tail water of the municipal sewage treatment plant has the characteristics of low carbon content, high concentration of nitrate nitrogen (NO3--N) in total nitrogen (TN), and a carbon-nitrogen ratio (C / N) of less than 3.5. If these waters are directly discharged without effective treatment, it will cause eutrophication of the receiving water body and destroy the water ecosystem.

[0004] Currently, although ecological measures have been used to remove nitrate nitrogen, in the northwest region with serious salinization, antibiotics and salinity exert selective pressure on denitrifying bacteria, inhibit the removal of nitrate nitrogen, and further cause eutrophication and other problems when entering rivers, which is not considered in the current technical solution. And with the development of urbanization, in economically developed and water resource-limited arid and semi-arid regions, the main focus of reclaimed water sources is the removal of conventional nitrogen and phosphorus, and the removal ability of salinity and antibiotics is poor. Antibiotics and salinity can affect the nitrogen cycle and transformation and the growth and enrichment of denitrifying microorganisms to different extents in the biological removal of nitrate nitrogen, interfere with the absorption of nutrients and the action of microorganisms in the wetland, and directly affect the nitrogen treatment efficiency in the wetland, which is a major hidden danger for water quality stability and improvement. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application discloses a device and method for layered adsorption-artificial wetland collaborative treatment of tail water to solve the problems raised in the background art.

[0006] To achieve the above purpose, the present application provides the following technical scheme: a device for layered adsorption-artificial wetland collaborative treatment of tail water, comprising a layered selective adsorption treatment unit, a pyrolysis treatment unit, and a reinforced artificial wetland unit.

[0007] ​The simulated wastewater enters the layered selective adsorption treatment unit through the first peristaltic pump, and antibiotics are removed through the layered selective adsorption treatment unit containing a cation adsorption layer, a hydrophobic adsorption layer and a polar adsorption layer. The adsorption material is transported to the pyrolysis treatment unit on one side, and the effluent treated by the layered selective adsorption treatment unit enters the enhanced constructed wetland unit through the second peristaltic pump, and the enhanced constructed wetland unit containing a gravel support layer, a biochar layer and a volcanic rock layer inoculated with salt-tolerant bacteria, thereby reducing the inhibitory effect of salinity and antibiotics on denitrifying microorganisms.

[0008] Preferably, the three-layer different function adsorption layers arranged inside the layered selective adsorption treatment unit are a cation adsorption layer, a hydrophobic adsorption layer and a polar adsorption layer from top to bottom. When the adsorption layer enriches antibiotics to a preset concentration threshold, the adsorption saturated adsorption material on the adsorption layer enters the pyrolysis treatment unit through the inclined guide groove arranged on one side in parallel, and the antibiotics are decomposed and regenerated into stable biochar through pyrolysis. The enriched antibiotics are decomposed through the pyrolysis treatment unit to generate stable biochar.

[0009] Preferably, a filter screen is arranged at the bottom of each of the three adsorption layers. Each of the three adsorption layers is 15 cm high and spaced 18 cm apart. The cation adsorption layer is filled with sodium-based bentonite with a particle size of 0.5-2 mm. Through the high specific surface area and negative charge layered structure, cationic antibiotics such as tetracycline antibiotics are adsorbed through cation exchange. The hydrophobic adsorption layer is filled with corn cob iron modified biochar with a particle size of 3-5 mm. Through the coordination and complexation provided by iron (Fe), the affinity for neutral antibiotics such as benzene amide, quinolone and macrolide is enhanced. The polar adsorption layer is filled with a compound of amino-modified biochar and modified ceramsite with a particle size of 1-4 mm. Through the mechanisms of hydrogen bonding, polar-polar interaction and electrostatic adsorption, polar strong, water-soluble and small structure antibiotics such as sulfonamides and β-lactam antibiotics are removed. 、 )provide coordination and complexation, enhance the affinity for neutral antibiotics such as benzene amide, quinolone and macrolide; and the polar adsorption layer is filled with a compound of amino-modified biochar and modified ceramsite with a particle size of 1-4 mm, which removes polar strong, water-soluble and small structure antibiotics such as sulfonamides and β-lactam antibiotics through the mechanisms of hydrogen bonding, polar-polar interaction and electrostatic adsorption.

[0010] Preferably, the three adsorption layers are connected with a sensor unit, and the indicators are transmitted through the transmission device. The indicators include ultraviolet absorption, total organic carbon, conductivity and pH.

[0011] Preferably, an automatic valve is arranged on the inclined guide groove. The saturation degree of the adsorption layer for adsorbing antibiotics is determined according to the indicators collected by the sensor unit, and the opening and closing of the automatic valve is controlled by a computer.

[0012] Preferably, the enhanced constructed wetland unit includes a gravel support layer, a biochar layer and a volcanic rock layer from bottom to top.

[0013] The volcanic rock layer is used for planting salt-tolerant plants reed, roots of the reed reach the volcanic rock layer; a plurality of salt-tolerant bacteria are inoculated in the volcanic rock layer; a gravel supporting layer is filled with gravel with an average particle size of 3-5 cm and has a height of 8 cm; a biochar layer is formed by mixing gravel and biochar, the biochar is mainly obtained by pyrolysis of the reed and has a particle size of 2-8 mm and a height of 5 cm, and the biochar mainly provides a carbon source for further reduction of nitrate nitrogen; the volcanic rock layer is formed by improving volcanic rock with an average particle size of 2-5 cm and has a height of 18 cm; and the planting density of the salt-tolerant plants reed on the surface of the volcanic rock layer is 30 plants per square meter. 2 .

[0014] Preferably, the pyrolysis treatment unit is provided with a temperature detection module for monitoring the temperature of the pyrolysis treatment unit.

[0015] The application also provides a method for treating tail water by using a layered adsorption-artificial wetland, comprising the following steps:

[0016] S1, the culture and start-up of the enhanced artificial wetland unit, all plants and substrates are cultured with simulated wastewater without antibiotics before the experiment, and salt-tolerant bacteria are inoculated to start microbial activity in the artificial wetland; then, the device is formally operated to treat wastewater;

[0017] S2, the simulated wastewater enters the layered selective adsorption treatment unit, the hydraulic retention time is set, different types of antibiotics are adsorbed under the action of the three-layer adsorption layer; whether the adsorbent is saturated is preliminarily judged by using a sensor unit; the upper limit of the saturation index is set to alarm and linkage judgment is performed, an automatic valve is triggered to perform pyrolysis treatment on the adsorbent;

[0018] S3, the effluent of the layered selective adsorption treatment unit enters the enhanced artificial wetland unit under the control of a second peristaltic pump, and the wetland is set to have a hydraulic retention time;

[0019] S4, the reaction in the volcanic rock layer of the wetland includes:

[0020]

[0021] That is, in the aerobic region, that is, close to the position of the plant roots, ammonia nitrogen is converted into nitrate nitrogen under nitrification, and the dissolved oxygen concentration is greater than 2 mg / L;

[0022] ;

[0023] That is, in the anoxic region, that is, away from the root position, nitrate nitrogen is converted into nitrogen by denitrification with biochar or organic carbon;

[0024] The inoculated salt-tolerant bacteria are beneficial to the adaptive growth of the bacterial flora and better adapt to the salt-containing wastewater; on the other hand, the inoculated salt-tolerant bacteria have a denitrification function and promote the denitrification function of the wetland;

[0025] The biochar layer provides a carbon source for the denitrifying bacteria group, and ensures an effective denitrification process.

[0026] Finally, nitrogen in the wastewater is effectively removed.

[0027] Compared with the prior art, the beneficial effects of the present application are:

[0028] 1. The present application realizes efficient removal of pollutants. Through the hierarchical selective adsorption treatment unit, according to the physical and chemical properties of different antibiotics, such as polarity, molecular structure, charge state and distribution coefficient, the specific adsorbent is set, which can efficiently remove the antibiotics in the tail water, significantly reducing the interference on the subsequent treatment unit. At the same time, the artificial wetland unit is strengthened, and the denitrification function of salt-tolerant bacteria is combined to effectively reduce the load of nitrate nitrogen and other nutrient salts, further improving the denitrification efficiency under salt conditions. This synergistic treatment method not only optimizes the pollutant removal effect, but also can accurately control the saturation degree of the adsorbent with the real-time monitoring device to prevent secondary release and ensure the stable operation of the whole treatment process.

[0029] 2. The present application improves the device operation efficiency and maintainability. The modular design is adopted, and the selection and replacement of adsorbent are more flexible and efficient. Through the hierarchical adsorption of bentonite, iron biochar and amino carbon, different types of antibiotics can be removed, and the automatic monitoring can accurately judge the adsorption saturation degree, so that the adsorbent can be replaced in time to avoid the performance decline of the device. In addition, the device as a whole does not depend on electricity or light, and the structure is simple, which is convenient for deployment and maintenance, reduces the operation cost and operation difficulty, and is suitable for application in different environmental conditions.

[0030] 3. The present application inoculates salt-tolerant bacteria in the enhanced artificial wetland unit, which can effectively alleviate the inhibition of salinity on denitrifying functional bacteria, and improve the adaptability and denitrification capacity of the wetland unit in high-salt environment. At the same time, the hierarchical selective adsorption treatment unit intercepts the antibiotics before they enter the wetland, further protecting the stability of the microbial structure in the wetland. This design not only enhances the ecological adaptability of the wetland unit, but also improves the overall sustainability through resource recycling, such as the pyrolysis of adsorbent to generate biochar, which meets the development direction of ecological friendly sewage treatment. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, which together with the embodiments of the present application, serve to explain the present application, and do not constitute a limitation of the present application.

[0032] In the drawings:

[0033] Figure 1 is a structural schematic diagram of the device for hierarchical adsorption-artificial wetland synergistic treatment of tail water of the present application.

[0034] Numbers in the figure: 1. Layered selective adsorption treatment unit; 2. Pyrolysis treatment unit; 3. Enhanced artificial wetland unit; 4. First peristaltic pump; 5. Cationic adsorption layer; 6. Hydrophobic adsorption layer; 7. Polar adsorption layer; 8. Filter screen; 9. Sensor unit; 10. Automatic valve; 11. Inclined guide trough; 12. Transmission device; 13. Computer; 14. Second peristaltic pump; 15. Gravel support layer; 16. Biochar layer; 17. Salt-tolerant bacteria; 18. Volcanic rock layer; 19. Salt-tolerant plants; 20. Temperature detection module. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0036] like Figure 1 As shown, the present invention provides a device for synergistically treating tail water by using a layered adsorption-constructed wetland, comprising a layered selective adsorption treatment unit 1, a pyrolysis treatment unit 2 and an enhanced constructed wetland unit 3;

[0037] The simulated wastewater enters the layered selective adsorption treatment unit 1 through the first peristaltic pump 4, and the effluent enters the enhanced artificial wetland unit 3 through the second peristaltic pump 14; the adsorption layer enters the pyrolysis treatment unit 2 through the inclined guide trough 11 arranged in parallel on one side, and an automatic valve 10 is provided on the inclined guide trough 11, and the switch of the automatic valve 10 is controlled by the computer 13. A temperature detection module 20 is provided in the pyrolysis treatment unit 2, and the temperature of the pyrolysis treatment unit 2 is monitored by the temperature detection module 20.

[0038] Specifically, the hierarchical selective adsorption treatment unit 1 is internally provided with three layers of different functional adsorption layers according to the complex characteristics of tail water antibiotics, which effectively adsorb different types of antibiotics. The three adsorption layers are all connected with sensor units 9 and transmit indicators through the transmission device 12, the indicators including ultraviolet absorption, total organic carbon, conductivity and pH. The saturation degree of the adsorption layer for antibiotic adsorption is determined according to the indicators collected by the sensor unit 9. Even if the treatment effect of antibiotics cannot be obtained in real time, the saturation degree of the adsorbent can be evaluated through indicators such as ultraviolet absorption, total organic carbon, conductivity and pH, and the parallel switch of the automatic valve 10 is automatically set to ensure the effective adsorption of the adsorbent. The hierarchical selective adsorption treatment unit 1 is composed of a cation adsorption layer 5, a hydrophobic adsorption layer 6 and a polar adsorption layer 7 from top to bottom. When the adsorption layer is enriched with antibiotics to a preset concentration threshold, the adsorption material is transported to the pyrolysis treatment unit 2 on one side through the inclined flow guide groove 11, and the enriched antibiotics are decomposed by the pyrolysis treatment unit 2 at 300°C for 2 hours to generate stable biochar. The bottom of each of the three adsorption layers is provided with a filter screen 8. Each layer of the three-layer adsorption layer is 15 cm high and spaced 18 cm apart. The cation adsorption layer 5 is filled with sodium-based bentonite with a particle size of 0.5-2 mm. Through the high specific surface area and negative charge layered structure, cationic antibiotics such as tetracycline antibiotics are adsorbed by cation exchange. The hydrophobic adsorption layer 6 is filled with corn cob iron modified biochar with a particle size of 3-5 mm. Through coordination and complexation, the affinity for neutral antibiotics such as benzene amide, quinolone and macrolide is enhanced. The polar adsorption layer 7 is filled with a compound of amino-modified biochar and modified ceramsite with a particle size of 1-4 mm. Through the mechanisms of hydrogen bonding, polar-polar interaction and electrostatic adsorption, antibiotics with strong polarity, high water solubility and small structure such as sulfonamides and β-lactam antibiotics are removed. The adsorption material of each layer is easy to obtain and can be recycled by pyrolysis. 、 )provide coordination and complexation, enhance the affinity for neutral antibiotics such as benzene amide, quinolone and macrolide; the polar adsorption layer 7 is filled with a compound of amino-modified biochar and modified ceramsite with a particle size of 1-4 mm, which removes antibiotics with strong polarity, high water solubility and small structure such as sulfonamides and β-lactam antibiotics through the mechanisms of hydrogen bonding, polar-polar interaction and electrostatic adsorption; the adsorption material of each layer is easy to obtain and can be recycled by pyrolysis.

[0039] Specifically, the enhanced constructed wetland unit 3 includes a gravel support layer 15, a biochar layer 16 and a volcanic rock layer 18 from bottom to top. The surface of the volcanic rock layer 18 is used for planting salt-tolerant plants 19 such as reeds, and the volcanic rock layer 18 is inoculated with various salt-tolerant bacteria 17. The gravel support layer 15 is filled with gravel with an average particle size of 3-5 cm and a height of 8 cm. The biochar layer 16 is composed of gravel and biochar mixed with each other, the biochar is mainly pyrolyzed from reeds to have a particle size of 2-8 mm and a height of 5 cm, and mainly provides a carbon source for further nitrate nitrogen reduction. The volcanic rock layer 18 is improved by volcanic rock with an average particle size of 2-5 cm and a height of 18 cm. The planting density of the salt-tolerant plants 19 such as reeds on the surface of the volcanic rock layer 18 is 30 plants / m 2The artificial wetland substrate is a biochar-sand mixed substrate, and the wetland improved by the biochar can effectively improve the reduction and removal of nitrate nitrogen. The biochar can provide habitat and nutrients required for the growth of microorganisms, and has stable chemical properties and is not easy to cause secondary pollution to the water body.

[0040] The application further provides a method for treating tail water by using the layered adsorption-artificial wetland.

[0041] S1, the culture and start-up of the enhanced artificial wetland unit 3; all plants and substrates are cultured with simulated wastewater without antibiotics for 30 days before the experiment, and salt-tolerant bacteria 17 (Halomonas denitrificans, Paracoccus halophilus and Desulfovibrio halophilus, etc.) are inoculated to start the microbial activity in the artificial wetland; then, the device is formally operated to treat wastewater;

[0042] S2, the simulated wastewater enters the layered selective adsorption treatment unit 1, and the hydraulic retention time is set to 2-4 days, so that different types of antibiotics are adsorbed under the action of the three-layer adsorption layer; the sensor unit 9 is used to collect data indexes, including:

[0043] UV-Vis (254 nm) sensor: C / C0≥0.85, wherein C represents the absorbance after adsorption treatment, and C0 represents the initial absorbance before adsorption treatment; when the ratio of the absorbance after adsorption treatment to the initial absorbance is greater than or equal to 0.85, it indicates that the adsorption effect of the adsorbent on the organic matter in the water is weakened, and the adsorption saturation degree is high;

[0044] TOC (total organic carbon) sensor: C / C0≥0.8-0.90, wherein C represents the TOC concentration after adsorption treatment, and C0 represents the initial TOC concentration before adsorption treatment; when the ratio of the TOC concentration after adsorption treatment to the initial concentration is greater than or equal to 0.8 to 0.90, it indicates that the adsorption capacity of the adsorbent on the organic matter has reached a certain degree and is close to the saturation state;

[0045] pH sensor: the change of the pH of the inlet and outlet water is ±0.3;

[0046] EC conductivity sensor: the difference between the inlet and outlet water is 20-30 μS / cm;

[0047] The above data indexes are used as the preliminary judgment of the saturation of the adsorbent; finally, the linkage judgment is performed, the saturation index SI is set to be greater than or equal to 0.85 as the upper limit of the alarm, and the automatic valve 10 is triggered to perform pyrolysis treatment on the adsorbent, wherein the formula is as follows:

[0048]

[0049] Wherein, UV 出 / UV 进 represents the ratio of the ultraviolet absorbance after adsorption treatment to the ultraviolet absorbance before adsorption treatment, TOC 出 / TOC 进 represents the ratio of the total organic carbon concentration after adsorption treatment to the total organic carbon concentration before adsorption treatment, represents the change of pH value of the influent and effluent water; represents the difference of conductivity of the influent and effluent water;

[0050] S3, the effluent of the layered selective adsorption treatment unit 1 is controlled by the second peristaltic pump 14 to enter the enhanced constructed wetland unit 3, and the wetland is set to have a hydraulic retention time of 8-12 hours;

[0051] S4, the reaction in the wetland volcanic rock layer 18 includes:

[0052]

[0053] In the aerobic area, i.e. near the position of the plant roots, ammonia nitrogen is converted into nitrate nitrogen under nitrification, and at this time the concentration of dissolved oxygen is greater than 2 mg / L;

[0054] ;

[0055] In the anoxic area, i.e. away from the root position, nitrate nitrogen is denitrified with biochar or organic carbon to convert into nitrogen gas;

[0056] The inoculated salt-tolerant bacteria 17 are beneficial to the adaptive growth of the bacterial flora, and better adapt to the salt-containing wastewater. On the other hand, the inoculated salt-tolerant bacteria 17 have a denitrification function, which promotes the denitrification function of the wetland. The biochar layer 16 provides a carbon source for the denitrification bacterial flora, ensuring an effective denitrification process. Finally, the nitrogen in the wastewater is effectively removed.

[0057] Experimental data of the performance of the obtained product or result are as shown in the following Tables 1 and 2:

[0058] 1) Table 1 is the configuration of simulated wastewater

[0059]

[0060] 2) Table 2 is the result of wastewater treatment

[0061]

[0062] Through the above device and method, the concentration of the effluent in the simulated wastewater ultimately meets the Class II water quality standard of GB 3838-2002 “Surface Water Environmental Quality Standard”, and the COD meets the Class III water quality standard, ​When the concentration is lower than 2 mg / L, the antibiotic removal rate reaches 55%-78%.

[0063] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A device for treating tail water by layered adsorption-artificial wetland cooperation, characterized in that: It comprises a hierarchical selective adsorption treatment unit (1), a pyrolysis treatment unit (2) and a reinforced constructed wetland unit (3); The simulated wastewater enters the hierarchical selective adsorption treatment unit (1) through the first peristaltic pump (4), and the antibiotics are removed through the hierarchical selective adsorption treatment unit (1) containing the cation adsorption layer (5), the hydrophobic adsorption layer (6) and the polar adsorption layer (7) respectively, the adsorption material is transported to the pyrolysis treatment unit (2) on one side, and the effluent treated by the adsorption unit enters the reinforced constructed wetland unit (3) through the second peristaltic pump (14) arranged, and the reinforced constructed wetland unit (3) containing the gravel support layer (15), the biochar layer (16) and the volcanic rock layer (18) inoculated with salt-tolerant bacteria (17) is used to further reduce the inhibitory effect of salinity and antibiotics on denitrifying microorganisms; The three adsorption layers arranged inside the hierarchical selective adsorption treatment unit (1) are the cation adsorption layer (5), the hydrophobic adsorption layer (6) and the polar adsorption layer (7) from top to bottom, when the adsorption layer enriches the antibiotics to a preset concentration threshold, the adsorption saturated adsorption material on the adsorption layer enters the pyrolysis treatment unit (2) through the inclined flow guide groove (11) arranged on one side, the antibiotics are decomposed by pyrolysis and regenerated into stable biochar, and the enriched antibiotics are decomposed by the pyrolysis treatment unit (2) to generate stable biochar; The filter screen (8) is arranged at the bottom of each of the three adsorption layers, wherein the cation adsorption layer (5) is filled with sodium-based bentonite with a particle size of 0.5-2 mm, and the cationic antibiotics are adsorbed through the high specific surface area and negative charge layered structure by cation exchange; the hydrophobic adsorption layer (6) is filled with corn cob iron modified biochar with a particle size of 3-5 mm, and the hydrophobic antibiotics are adsorbed by providing coordination and complexation through iron; the polar adsorption layer (7) is filled with a compound of amino-functionalized biochar and modified ceramsite with a particle size of 1-4 mm, and the polar antibiotics are removed by the mechanisms of hydrogen bonding, polarity-polarity interaction and electrostatic adsorption.

2. The device for treating tail water in a layered adsorption-artificial wetland according to claim 1, characterized in that: The sensor unit (9) is connected to each of the three adsorption layers, and the indicators are transmitted through the transmission device (12) arranged, the indicators include ultraviolet absorption, total organic carbon, conductivity and pH.

3. The device for treating tail water in a layered adsorption-artificial wetland according to claim 2, characterized in that: The automatic valve (10) is arranged on the inclined flow guide groove (11), the saturation degree of the adsorption layer for adsorbing antibiotics is determined according to the indicators collected by the sensor unit (9), and the opening and closing of the automatic valve (10) is regulated by the computer (13).

4. The device for treating tail water in a layered adsorption-artificial wetland according to claim 1, characterized in that: The reinforced constructed wetland unit (3) comprises the gravel support layer (15), the biochar layer (16) and the volcanic rock layer (18) from bottom to top; The surface of the volcanic rock layer (18) is used for planting salt-tolerant plants (19); the gravel support layer (15) is filled with gravel with an average particle size of 3-5 cm; the biochar layer (16) comprises gravel and biochar mixed with each other.

5. The device for treating tail water by hierarchical adsorption and constructed wetland according to claim 1, characterized in that: The pyrolysis treatment unit (3) is provided with a temperature detection module (20) for monitoring the temperature of the pyrolysis treatment unit (3).

6. A method for treating tail water by layered adsorption-artificial wetland cooperation, based on the device of any one of claims 1-5, characterized in that: It comprises the following steps: S1, the cultivation and start-up of the enhanced constructed wetland unit (3), all plants and substrates are cultured with simulated wastewater without antibiotics before the experiment, and salt-tolerant bacteria (17) are inoculated to start microbial activity in the constructed wetland; Then, the device is formally operated to treat wastewater; S2, the simulated wastewater enters the layered selective adsorption treatment unit (1), the hydraulic retention time is set, different types of antibiotics are adsorbed under the action of three adsorption layers; the sensor unit (9) is used to preliminarily judge whether the adsorbent is saturated; the linkage judgment is carried out by setting the upper limit of the saturation index alarm, the automatic valve (10) is triggered, and the adsorbent is pyrolyzed; S3, the effluent of the layered selective adsorption treatment unit (1) is controlled by the second peristaltic pump (14) and enters the enhanced constructed wetland unit (3), and the wetland sets the hydraulic retention time; S4, the reaction in the wetland volcanic rock layer (18) includes: In the aerobic area, i.e. near the plant root position, ammonia nitrogen is converted into nitrate nitrogen under nitrification, and the dissolved oxygen concentration is greater than 2 mg / L at this time; In the anoxic area, i.e. away from the root position, nitrate nitrogen and biochar or organic carbon occur denitrification, and are converted into nitrogen gas; The inoculated salt-tolerant bacteria (17) can survive in salt-containing wastewater after domestication, and the bacterial flora itself has a denitrification function, thereby promoting the denitrification effect of the wetland; The biochar layer (16) provides a carbon source for the denitrifying bacteria flora; Finally, nitrogen in the wastewater is effectively removed.

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