Purification system and method for removing conventional pollutants and antibiotic resistance genes of garbage leachate

Abstract

The invention discloses a purification system and method for removing conventional pollutants and antibiotic resistance genes in garbage penetrating fluid, and belongs to the technical field of sewage treatment.The purification system comprises a pre-sedimentation tank, a purification tank, a nanofiltration membrane module device, a clean water tank, a concentrated water tank and a backwashing system, and the upper portion of the pre-sedimentation tank is communicated with an adjusting tank through a conveying pipeline; the purification tank comprises a flocculation tank and an inclined plate sedimentation tank which are adjacently communicated, and the flocculation tank is communicated with the regulating tank through a conveying pipeline; the liquid inlet end of the nanofiltration membrane unit is communicated with an overflow pipe of the inclined plate sedimentation tank, the clean water tank is communicated with the water outlet end of the nanofiltration membrane unit, and the concentrated water tank is communicated with one water outlet end of the nanofiltration membrane unit; the backwashing system is communicated with the water outlet end of the nanofiltration membrane module and is used for backwashing the nanofiltration membrane module. According to the method, a flocculation process and a nanofiltration process are combined, the concentration of pollutants can be greatly reduced in the flocculation process, membrane pollution caused by the fact that a large number of pollutants enter a nanofiltration membrane is avoided, and removal of conventional pollutants and ARGs is enhanced in the nanofiltration process.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a purification system and method for removing conventional pollutants and antibiotic resistance genes from garbage leachate. Background Art

[0002] Antibiotics are key medicines for treating common and complicated infections in humans, animals, and crops. Antibiotic resistance (AR) in microorganisms reduces the effectiveness of these medicines or even makes them ineffective, thus seriously endangering public health. Since the 21st century, due to the abuse of antibiotics, if appropriate measures are not taken, the number of casualties caused by antibiotic resistance may reach 10 million per year by 2050. The harm caused by the increasing antibiotic resistance cannot be ignored. In the past decade, the development, maintenance, and spread of AR in different environmental media such as wastewater have become increasingly serious, and it is widely present in systems such as sludge, surface water, groundwater, and landfills. Among them, sanitary landfill is the main method for treating urban solid waste worldwide. Unused or unnecessary antibiotics and antibiotic resistance in domestic waste such as toilet paper, diapers and home medical care enter the landfill together with domestic waste, forming antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). AR in landfills is transported into the environment through leachate. Landfills and leachate are important reservoirs of antibiotics and ARGs, providing a breeding ground for the exchange of ARGs between strains through horizontal gene transfer (HGT).

[0003] Wastewater treatment plants (WWTPs) serve as reservoirs of ARGs, receiving antibiotic discharges from hospitals, residents, and agriculture, which is considered an important way to prevent the release of ARGs into the urban environment. However, traditional WWTPs are not designed to remove ARGs, and the relative abundance of ARGs in effluent from WWTPs can reach 105~108 copies / L. After conventional biological treatment processes, post-treatment methods should be considered to avoid excessive ARGs discharged into receiving waters, which can have a serious impact on the human living environment. Summary of the invention

[0004] Technical problems to be solved: In view of the shortcomings in the prior art, the present invention provides a purification system and method for removing conventional pollutants and antibiotic resistance genes in garbage leachate, which combines the flocculation process with the nanofiltration process, and utilizes the adsorption, sweeping, hydrophobic association and other effects of coagulation to significantly reduce the concentration of pollutants in the preliminary treatment of the leachate, and enhances the removal of conventional pollutants and ARGs in the nanofiltration process. The flocculation process avoids membrane pollution caused by a large amount of pollutants entering the nanofiltration membrane, thereby extending the service life of the nanofiltration membrane and reducing production costs.

[0005] Technical solution: The purification system for removing conventional pollutants and antibiotic resistance genes from garbage leachate according to the present invention comprises: A pre-sedimentation tank, the upper part of which is connected to the regulating tank through a conveying pipeline; A purification tank, the purification tank comprising a flocculation tank and an inclined plate settling tank arranged adjacent to each other, the flocculation tank being connected to the regulating tank through a conveying pipeline; A nanofiltration membrane module, wherein the liquid inlet end of the nanofiltration membrane module is connected to the overflow pipe of the inclined plate sedimentation tank; A clear water tank, the clear water tank is connected to the water outlet of the nanofiltration membrane module; A concentrated water tank, the concentrated water tank is connected to one of the water outlet ends of the nanofiltration membrane module; A backwashing system is connected to the water outlet of the nanofiltration membrane module to backwash the nanofiltration membrane module.

[0006] Preferably, the flocculation tank is separated into four flocculation chambers by three partition longitudinal plates along its flow direction, and the opening ends of two adjacent partition longitudinal plates are arranged alternately; a flocculant storage tank is arranged above the flocculation tank, and the flocculant mother liquid enters the flocculation tank through a feed pump and a feed valve, and a mechanical agitator is arranged in each of the four flocculation chambers; The lower opening of the first partition longitudinal plate, the upper opening of the second partition longitudinal plate, and the lower opening of the third partition longitudinal plate are respectively the liquid passage and the overflow port for the liquid phase to pass through; The flocculation tank and the inclined plate sedimentation tank are separated by a fourth dividing longitudinal plate. The upper end opening of the fourth dividing longitudinal plate forms an overflow port for the supernatant of the flocculation tank to overflow into the inclined plate sedimentation tank. The inclined plate sedimentation tank is provided with a plurality of dividing inclined plates with an inclined angle of 50 to 70 degrees with the horizontal plane.

[0007] Preferably, the bottoms of the pre-sedimentation tank, flocculation tank and inclined plate sedimentation tank are all provided with mud discharge ports and mud discharge branch pipes connected to the mud discharge ports, multiple mud discharge branch pipes are respectively connected to the mud discharge main pipe, and each mud discharge branch pipe is connected to a mud discharge valve; the mud discharge cycle is 2~5h.

[0008] Preferably, the nanofiltration membrane assembly is composed of a plurality of ultrafiltration and nanofiltration membranes connected in parallel; the nanofiltration membrane assembly is a hollow fiber membrane, a rolled or tubular membrane; and its material is a polyamide composite membrane, polyamide, polypropylene, polyether sulfone, or polyvinyl alcohol.

[0009] Preferably, the pore size of the ultrafiltration nanofiltration membrane is 200-1000 Daltons, which is between the pore size of ultrafiltration and reverse osmosis; the operating pressure of the nanofiltration membrane module is 0.2-1.0 MPa.

[0010] Preferably, the backwashing system comprises a cleaning tank, which is connected to the water outlet of the nanofiltration membrane module through a delivery pipeline, and a backwashing pump is connected to the delivery pipeline; the backwashing cycle of the nanofiltration membrane module is 1.0~4.0h, and the backwashing time each time is 10~30min.

[0011] The present invention also discloses a purification method for removing conventional pollutants and antibiotic resistance genes from garbage leachate, comprising the following steps: Step 1: The landfill leachate after biological treatment is transported to the pre-sedimentation tank, where it is allowed to stand to remove a large number of large particle pollutants. The supernatant of the pre-sedimentation tank is injected into the regulating tank through a feed pump; Step 2: The landfill leachate that has undergone preliminary sedimentation in the regulating tank is transported to the flocculation tank of the purification tank through a feed pump. At the same time, a flocculant is added to the flocculation tank through a flocculant dosing pump, and the mechanical agitator set in each flocculation chamber is started to allow the flocculant to fully react with the landfill leachate to remove conventional pollutants, microorganisms and ARGs in the landfill leachate; Step 3: The landfill leachate flocculated in the flocculation tank enters the inclined plate settling tank through the fourth dividing longitudinal plate, and a large amount of pollutants in the landfill leachate enters the sedimentation sludge; Step 4: After sufficient sedimentation in the inclined plate settling tank, the overflow enters the nanofiltration membrane group to remove small molecules and ARGs in the landfill leachate. The clear liquid purified by the nanofiltration membrane enters the clear water tank or cleaning tank. The large particles of floccules that cannot pass through the nanofiltration membrane are retained outside the nanofiltration membrane and enter the concentrated water tank. The treatment time of the nanofiltration membrane group is 1.5~4.5 hours; Step 5: The nanofiltration membrane module is cleaned regularly after use, and the cleaning liquid is transported to the nanofiltration membrane module through the backwashing system to backwash the nanofiltration membrane and then transported to the concentrated water tank for storage; Step 6: The pre-sedimentation tank, flocculation tank and inclined plate sedimentation tank are periodically discharged through the sludge discharge system.

[0012] Preferably, the flocculant in step 2 is a chitosan-based flocculant, and its structural formula is shown in Formula 1 and Formula 2: (1); In formula 1: poly N-n-propyl acrylamide, poly N-isopropyl acrylamide and polyacryloylpiperidine are grafted onto chitosan, respectively, wherein x:y is a molar ratio, the value range of x:y= is 1:(3-15), and the mass ratio of chitosan monomer to substance R is defined as m1:m2, and the value range is 1:(5-20); (2); In formula 2: n is the average degree of polymerization, the value range of a:b is (4~12):1, and the mass ratio of Al hydroxide to R M1:M2 is 1: (1.38~6.90).

[0013] Preferably, the concentration of flocculant added in step 2 is 1-3 g / L; the stirring speed in the first flocculation chamber is 250-300 r / min, the stirring speed in the second flocculation chamber is 150-200 r / min, the stirring speed in the third flocculation chamber is 100-150 r / min, and the stirring speed in the fourth flocculation chamber is 40-90 r / min.

[0014] Preferably, the flocculation solution flowing out of the flocculation tank in step 3 stays in the inclined plate settling tank for 15 to 45 minutes.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The present invention combines the flocculation process with the nanofiltration process, and utilizes the effects of adsorption, sweeping, hydrophobic association, etc. of coagulation to significantly reduce the concentration of pollutants in the preliminary treatment of the leachate, and strengthens the removal of conventional pollutants and ARGs in the nanofiltration process. The flocculation process avoids membrane pollution caused by a large amount of pollutants entering the nanofiltration membrane, prolongs the service life of the nanofiltration membrane, and reduces production costs; the pre-sedimentation tank performs preliminary purification on the landfill leachate, and gravity sedimentation purification can remove a large amount of large particle pollutants in the landfill leachate; the flocculation performance of the hydrophobic modified flocculant is combined with the inclined plate sedimentation tank and the nanofiltration membrane assembly, and the excellent flocculation of the hydrophobic modified flocculant improves the effect of removing pollutants and reduces the use of subsequent processes; 2. The flocculant adopts a hydrophobic organic chain-modified chitosan flocculant. Chitosan is a commonly used industrial raw material with abundant output and low price. The flocculant based on chitosan has great application potential in terms of economic cost. The inorganic metal oxide flocculant is modified by a hydrophobic organic chain. The organic part and the inorganic part are chemically combined through the silane coupling agent structure. The organic end on the obtained hybrid product has a strong binding force with the organic group on the pollutant, which can form a large-size and dense flocculent. The inorganic end of the hybrid product forms a flocculent through rapid nucleation, removes pollutants, and reduces the cost of the flocculant. The flocculant enhances the hydrophobic association between the flocculant and small molecular organic matter (ARGs) through the hydrophobic effect of the long carbon chain, effectively improving the removal of ARGs in sewage by the flocculant. 3. The present invention can simultaneously remove conventional pollutants and pollutants of antibiotic resistance genes in landfill leachate, and has the advantages of simple operation and maintenance, low cost, high performance, and easy transformation and application in engineering projects; the process has a large processing capacity and can be flexibly adjusted according to actual needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1It is a schematic diagram of the process of the purification system of the present invention; Figure 2 is a bar graph of the removal rate of antibiotic resistance genes in Example 2 of the present invention; Figure 3 is a bar graph of the removal rate of antibiotic resistance genes in Example 3 of the present invention; Figure 4 is a bar graph of the removal rate of antibiotic resistance genes in Example 4 of the present invention; Figure 5 is a bar graph of the removal rate of antibiotic resistance genes in Example 5 of the present invention; Figure 6 is a bar graph of the removal rate of antibiotic resistance genes in Example 6 of the present invention; Figure 7 This is a bar graph showing the removal rate of antibiotic resistance genes in Example 7 of the present invention.

[0017] Figure numerals: 1. feed pump; 2. feed valve; 3. pre-sedimentation tank; 4. regulating tank; 5. flocculant storage tank; 6. mechanical agitator; 7. first partition longitudinal plate; 8. second partition longitudinal plate; 9. third partition longitudinal plate; 10. fourth partition longitudinal plate; 11. fifth partition longitudinal plate; 12. partition inclined plate; 13. sixth partition longitudinal plate; 14. first flocculation chamber; 15. second flocculation chamber; 16. third flocculation chamber; 17. fourth flocculation chamber; 18. inclined plate sedimentation tank; 19. nanofiltration membrane module; 20. cleaning tank; 21. clear water tank; 22. concentrated water tank; 23. backwash pump; 24. mud discharge port; 25. mud discharge main pipe; 26. vacuum pressure gauge; 27. mud discharge valve; 28. mud discharge pump; 29. ​​flocculation tank. DETAILED DESCRIPTION

[0018] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the following will be combined with the attached Figures 1 to 7 The technical solutions of the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0019] like Figure 1As shown, a purification system for removing conventional pollutants and antibiotic resistance genes from garbage leachate of the present invention comprises a pre-sedimentation tank 3, a purification tank, a nanofiltration membrane module 19, a clear water tank 21, a concentrated water tank 22 and a backwashing system. The pre-sedimentation tank 3 is connected to the incoming material pipeline, and the incoming material pipeline is connected to a feed pump 1 and a feed valve 2. The garbage leachate after biological treatment is transported to the pre-sedimentation tank 3 by the feed pump 1 for pre-sedimentation treatment. The upper part of the pre-sedimentation tank 3 is connected to the regulating tank 4 through a conveying pipeline, and the conveying pipeline is connected to the feed pump 1. The supernatant in the pre-sedimentation tank 3 is transported to the regulating tank 4 by the feed pump. The purification tank comprises a flocculation tank 29 and an inclined plate sedimentation tank 18 arranged adjacent to each other. The flocculation tank 29 is connected to the outlet end of the regulating tank 4 through a conveying pipeline. The clear liquid of the garbage leachate in the regulating tank 4 is continuously transported to the flocculation tank 29 by the feed pump for subsequent purification treatment.

[0020] The flocculation tank 29 is separated into four flocculation chambers along its flow direction by three partition longitudinal plates, and the opening ends of two adjacent partition longitudinal plates are arranged alternately; specifically, the flocculation tank 29 is separated into a first flocculation chamber 14, a second flocculation chamber 15, a third flocculation chamber 16, and a fourth flocculation chamber 17 by a first partition longitudinal plate 7, a second partition longitudinal plate 8, and a third partition longitudinal plate 9. A mechanical agitator 6 is provided in the first flocculation chamber 14, the second flocculation chamber 15, the third flocculation chamber 16, and the fourth flocculation chamber 17. The mechanical agitator 6 can strongly stir the reaction solution in the flocculation chamber; the stirring speed in the first flocculation chamber 14 is 250~300 r / min, the stirring speed in the second flocculation chamber 15 is 150~200 r / min, the stirring speed in the third flocculation chamber 16 is 100~150r / min, and the stirring speed in the fourth flocculation chamber 17 is 40~90r / min. A flocculant storage tank 5 is arranged above the flocculation tank 29, and the flocculant storage tank 5 is controlled by a feed pump and a feed valve to allow the flocculant mother liquid to enter the flocculation tank 29. The flocculation tank 29 is separated from the inclined plate settling tank 18 by a fourth partition longitudinal plate 10, and the lower end opening of the first partition longitudinal plate 7, the upper end opening of the second partition longitudinal plate 8, and the lower end opening of the third partition longitudinal plate 9 are respectively provided as a liquid passage and an overflow port for the liquid phase to pass through; the upper end opening of the fourth partition longitudinal plate 10 forms an overflow port for the supernatant of the flocculation tank to overflow into the inclined plate settling tank 18, and a plurality of partition inclined plates 12 with an angle of 50 to 70 degrees with respect to the horizontal plane are arranged in the inclined plate settling tank 18; a fifth partition longitudinal plate 11 is arranged at the end of the inclined plate settling tank 18.

[0021] During operation, the garbage leachate to be purified enters the second flocculation chamber from the first flocculation chamber through the liquid outlet at the lower end of the first partition longitudinal plate, and the liquid in the second flocculation chamber enters the third flocculation chamber through the overflow outlet at the top of the second partition longitudinal plate, and so on; the liquid in the flocculation tank 29 enters the inclined plate sedimentation tank 18 through the overflow outlet at the top of the fourth partition longitudinal plate for sedimentation and removal of flocculants. A fifth partition longitudinal plate 11 is provided at the front end of the inclined plate sedimentation tank 18 corresponding to the fourth partition longitudinal plate 10, and a liquid outlet is provided at the lower end of the fifth partition longitudinal plate 11. The flocculation solution entering the inclined plate sedimentation tank 18 enters the area of ​​the partition inclined plate 12 through the liquid outlet at the lower end of the fifth partition longitudinal plate 11, so that the precipitated pollutants are kept below each partition inclined plate 12 as much as possible, and the supernatant filtered and blocked by the partition inclined plate 12 overflows from the tail end of the inclined plate sedimentation tank 18 for subsequent treatment. The main function of the flocculation tank 29 is to remove conventional pollutants (suspended particles, humus, etc.) and antibiotic resistance genes in the landfill leachate; a partition inclined plate 12 is arranged in parallel in the inclined plate sedimentation tank 18. The function of the partition inclined plate 12 is to make the clear liquid flow along the upper layer of the partition inclined plate, and the separated floc particles slide downward along the lower side of the partition inclined plate 12 to the bottom of the inclined plate sedimentation tank 18 under the action of gravity. Due to the application of the principle of "shallow sedimentation", the sedimentation distance of the floc particles is shortened, thereby shortening the sedimentation time, improving the sedimentation efficiency, and avoiding entering the nanofiltration membrane group 19 to cause blockage of the nanofiltration membrane; the main function of the nanofiltration membrane group 19 is to further remove conventional pollutants and antibiotic resistance genes that are not removed in the flocculation stage.

[0022] The liquid inlet end of the nanofiltration membrane assembly 19 is connected to the overflow pipe of the inclined plate sedimentation tank. The nanofiltration membrane assembly 19 is composed of multiple ultrafiltration nanofiltration membranes connected in parallel. The pore size of the ultrafiltration nanofiltration membrane is 200-1000 Daltons, which is between ultrafiltration and reverse osmosis. The operating pressure of the nanofiltration membrane assembly 19 is 0.2-1.0 MPa. The nanofiltration membrane assembly 19 adopts one of hollow fiber membranes, roll or tubular membranes, and its material is one of polyamide composite membranes, polyamide, polypropylene, polyether sulfone, and polyvinyl alcohol.

[0023] The outlet of the nanofiltration membrane module 19 is provided with a clear water tank 21, a concentrated water tank 22 and a backwashing system. The backwashing system includes a cleaning tank 20, which is connected to the outlet of the nanofiltration membrane module 19 through a delivery pipe, and a backwashing pump 23 is connected to the delivery pipe; specifically, the nanofiltration membrane module 19 is provided with two outlets, wherein the outlet of the sewage after being filtered by the nanofiltration membrane is called the inner outlet, and the clean water after being purified by the nanofiltration membrane module 19 flows into the clear water tank 21 through the inner outlet; the outlet where the sewage intercepted by the nanofiltration membrane flows out is called the outer outlet, and the sewage flows into the concentrated water tank 22 through the outer outlet; the cleaning tank 20 enters the nanofiltration membrane module 19 through the inner outlet through the backwashing pump 23, and the nanofiltration membrane is backwashed, and the backwashing water is discharged to the concentrated water tank 22 through the outer outlet. The backwashing cycle of the nanofiltration membrane module 19 is 1.0~4.0h, and the backwashing time is 10~30min each time. During operation, after sufficient sedimentation in the inclined plate sedimentation tank 18, the overflow enters the nanofiltration membrane module 19 to remove small molecular substances and ARGs in the landfill leachate. The clear liquid purified by the nanofiltration membrane enters the clean water tank 21. The delivery pipeline connected to the clean water 21 is connected with a vacuum pressure gauge 26, a control valve and a backwash pump 23. The cleaning tank 20 and the clean water tank 21 can both be used as the source of cleaning water for the nanofiltration membrane module 19. The concentrated water after cleaning the nanofiltration membrane module 19 is discharged through the delivery pipeline to the concentrated water tank 22 for storage. The concentrated water tank 22 is connected to the pre-sedimentation tank 3 through the delivery pipeline. The concentrated water is delivered to the pre-sedimentation tank 3 by the feed pump to be fully mixed with the incoming liquid for pre-sedimentation. In order to ensure the membrane flux of the nanofiltration membrane, the nanofiltration membrane assembly 19 needs to be backwashed regularly during operation. The backwashing water is the effluent water treated by the nanofiltration membrane. Under the action of the effluent / backwashing pump 23, the clean water flows out from the inside to the outside of the nanofiltration membrane, and the pollutants attached to the outside of the nanofiltration membrane can be separated from the membrane.

[0024] A flocculant storage tank 5 is correspondingly arranged above the front end of the flocculation tank 29. The flocculant storage tank 5 stores a hydrophobic organic chain modified chitosan flocculant. A dosing pipe is arranged at the bottom of the flocculant storage tank 5. A dosing pump and a dosing valve are connected to the dosing pipe to control the flow of the flocculant. After the landfill leachate enters the purification tank, the dosing pump is started to add the flocculant to the purification tank at a set flow rate to mix with the landfill leachate for flocculation reaction; the added concentration of the flocculant is 1-3g / L.

[0025] A mud discharge port 24 and a mud discharge branch pipe connected to the mud discharge port 24 are arranged at the bottom of the pre-sedimentation tank 3, the flocculation tank 29 and the inclined plate sedimentation tank 18. Each mud discharge branch pipe is connected to a mud discharge valve 27. A plurality of mud discharge branch pipes are respectively connected to a mud discharge main pipe 25. A mud discharge pump 28 is arranged at the end of the mud discharge main pipe 25. The mud discharge cycle is controlled to be 2 to 5 hours by the mud discharge pump 28.

[0026] The pre-sedimentation tank of the present invention performs preliminary purification on the landfill leachate, and a large number of large particle pollutants in the landfill leachate can be removed by gravity sedimentation purification; the flocculation performance of the hydrophobic modified flocculant is combined with the inclined plate sedimentation tank and the nanofiltration membrane assembly, the excellent flocculation of the hydrophobic modified flocculant improves the effect of removing pollutants, reduces the use of subsequent processes such as ultrafiltration, can effectively reduce the pressure of removing pollutants in the nanofiltration process, prolongs the service life of the nanofiltration membrane, and greatly saves economic costs; the process can simultaneously remove conventional pollutants and pollutants of antibiotic resistance genes in the landfill leachate, and has the advantages of simple operation and maintenance, low cost, high performance, and easy transformation and application in engineering; the process has a large processing capacity and can be flexibly adjusted according to actual needs.

[0027] The present invention also discloses a purification method for removing conventional pollutants and antibiotic resistance genes from garbage leachate, comprising the following steps: Step 1: The landfill leachate after biological treatment is transported to the pre-sedimentation tank 3, and the liquid inlet flow rate is 50L / h. A large number of large particle pollutants are removed by standing in the pre-sedimentation tank 3, and can be discharged periodically through the mud discharge pipe. Through pre-sedimentation treatment, the pollutant concentration in the landfill leachate can be reduced, thereby reducing the amount of flocculant and the pressure of the subsequent nanofiltration stage, saving purification costs; the supernatant of the pre-sedimentation tank 3 is injected into the regulating tank 4 through the feed pump.

[0028] Step 2: The landfill leachate that has undergone preliminary precipitation in the regulating tank 4 is transported to the flocculation tank of the purification tank through a feed pump, and at the same time, the flocculant is added to the flocculation tank through a flocculant dosing pump, and the concentration of the flocculant added is 1~3g / L. The mechanical agitator 6 set in each flocculation chamber is started, the stirring speed of the first flocculation chamber 14 is 250~300 r / min, the stirring speed in the second flocculation chamber 15 is 150~200 r / min, the stirring speed in the third flocculation chamber 16 is 100~150r / min, and the stirring speed in the fourth flocculation chamber 16 is set to 40~90 r / min. As the stirring speed in each flocculation chamber gradually decreases, the flocculant and the landfill leachate are fully flocculated, and the flocculants are gradually settled to the bottom of the flocculation chamber to remove conventional pollutants, microorganisms and ARGs in the landfill leachate.

[0029] Step 3: After flocculation in the flocculation tank, the landfill leachate enters the inclined plate settling tank 18 through the fourth dividing longitudinal plate 10. The polluted landfill leachate stays in the inclined plate settling tank 18 for 15 to 45 minutes. After sufficient sedimentation in the inclined plate settling tank 18, its supernatant rises along the dividing inclined plate and is transported to the nanofiltration membrane module 19 through the overflow pipe for subsequent purification treatment; the floccules are deposited at the bottom of the inclined plate settling tank 18 along the dividing inclined plate under the action of gravity, and a large amount of pollutants in the landfill leachate enter the sedimentation sludge and are periodically discharged through the sludge discharge pipe. The inclined plate settling tank 18 can shorten the sedimentation distance and time of the floccules and improve the sedimentation efficiency of the floccules.

[0030] Step 4: After sufficient sedimentation in the inclined plate settling tank 18, the overflow enters the nanofiltration membrane module 19 to remove small molecular substances and ARGs in the landfill leachate. The clear liquid after purification by the nanofiltration membrane enters the clear water tank 21 or the cleaning tank 20. The large particle flocs that cannot pass through the nanofiltration membrane are retained outside the nanofiltration membrane, and the concentrated water enters the concentrated water tank 22. The treatment time of the nanofiltration membrane module 19 is 1.5~4.5 hours.

[0031] Step 5: The nanofiltration membrane module 19 is cleaned regularly after use, and the cleaning liquid is transported to the nanofiltration membrane module through the backwashing system to backwash the nanofiltration membrane and then transported to the concentrated water tank 22 for storage. The backwashing cycle of the nanofiltration membrane module 19 is 1.0~4.0h, and the backwashing time is 10~30min.

[0032] Step 6: The pre-sedimentation tank 3, the flocculation tank 29, and the inclined plate sedimentation tank 18 are periodically discharged through the sludge discharge system, and the sludge discharge cycle is 2 to 5 hours.

[0033] The flocculant used in the present invention is a chitosan-based flocculant, and its structural formula is shown in Formula 1 and Formula 2: (1); In formula 1: poly N-n-propyl acrylamide, poly N-isopropyl acrylamide and polyacryloylpiperidine are grafted onto chitosan, respectively, wherein x:y is a molar ratio, the value range of x:y= is 1:(3-15), and the mass ratio of chitosan monomer to substance R is defined as m1:m2, and the value range is 1:(5-20); (2); In formula 2: n is the average degree of polymerization, the value range of a:b is (4~12):1, and the mass ratio of Al hydroxide to R M1:M2 is 1: (1.38~6.90).

[0034] Example 1: A sample of landfill leachate to be purified is taken and purified by using the purification system for removing conventional pollutants and antibiotic resistance genes in landfill leachate of the present invention, which specifically comprises the following steps: Step 1: The landfill leachate after biological treatment is transported to the pre-sedimentation tank 3 with a liquid inlet flow rate of 50L / h. It is allowed to stand in the pre-sedimentation tank 3 for 30 minutes to remove a large number of large particle pollutants. The supernatant of the pre-sedimentation tank 3 is injected into the regulating tank 4 through the feed pump.

[0035] Step 2: The landfill leachate after preliminary precipitation in the regulating tank 4 is transported to the flocculation tank of the purification tank through the feed pump, and at the same time, the flocculant is added to the flocculation tank through the flocculant dosing pump, the concentration of the flocculant is 10 g / L, and the dosage of the flocculant is 1.7 g / L; the flocculant shown in the structure of formula 1 is used, wherein x:y=1:3, m1:m2=1:5. The mechanical agitator 6 set in each flocculation chamber is started, the stirring speed of the first flocculation chamber 14 is 260r / min, the stirring speed in the second flocculation chamber 15 is 200r / min, the stirring speed in the third flocculation chamber 16 is 120r / min, and the stirring speed in the fourth flocculation chamber 16 is set to 60r / min to remove conventional pollutants, microorganisms and ARGs in the landfill leachate.

[0036] Step 3: The landfill leachate flocculated in the flocculation tank enters the inclined plate settling tank 18 through the fourth dividing longitudinal plate 10. The polluted landfill leachate stays in the inclined plate settling tank 18 for 15 minutes, and a large amount of pollutants in the landfill leachate enters the precipitated sludge.

[0037] Step 4: After sufficient sedimentation in the inclined plate settling tank 18, the overflow enters the nanofiltration membrane module 19 to remove small molecular substances and ARGs in the landfill leachate. The clear liquid after purification by the nanofiltration membrane enters the clear water tank 21 or the cleaning tank 20. The large particle flocs that cannot pass through the nanofiltration membrane are retained outside the nanofiltration membrane, and the concentrated water enters the concentrated water tank 22. The treatment time of the nanofiltration membrane module 19 is 1.5 h.

[0038] Step 5: The nanofiltration membrane module 19 is cleaned regularly after use, and the cleaning liquid is transported to the nanofiltration membrane module through the backwashing system to backwash the nanofiltration membrane and then transported to the concentrated water tank 22 for storage. The backwashing cycle is 4.0 hours and the backwashing time is 10 minutes.

[0039] Step 6: The pre-sedimentation tank 3, the flocculation tank 29, and the inclined plate sedimentation tank 18 are periodically discharged through the sludge discharge system, and the sludge discharge cycle is 5 hours.

[0040] Example 2: Take the garbage leachate sample to be purified as shown in Table 1, and use the purification system for removing conventional pollutants and antibiotic resistance genes in garbage leachate of the present invention for purification treatment, which specifically includes the following steps: Step 1: The biologically treated leachate is transported to the pre-sedimentation tank 3 with a liquid inlet flow rate of 50 L / h. It is allowed to stand in the pre-sedimentation tank 3 for 20 minutes to remove a large number of large particle pollutants. The supernatant of the pre-sedimentation tank 3 is injected into the regulating tank 4 through a feed pump.

[0041] Step 2: The landfill leachate after preliminary precipitation in the regulating tank 4 is transported to the flocculation tank of the purification tank through the feed pump, and at the same time, the flocculant is added to the flocculation tank through the flocculant dosing pump, the concentration of the flocculant is 10 g / L, and the dosage of the flocculant is 0.8 g / L; the flocculant shown in the structure of Formula 1 is used, wherein x:y=1:6, m1:m2=1:10. The mechanical agitator 6 set in each flocculation chamber is started, the stirring speed of the first flocculation chamber 14 is 250r / min, the stirring speed in the second flocculation chamber 15 is 150r / min, the stirring speed in the third flocculation chamber 16 is 100r / min, and the stirring speed in the fourth flocculation chamber 16 is set to 50r / min to remove conventional pollutants, microorganisms and ARGs in the landfill leachate.

[0042] Step 3: The landfill leachate flocculated in the flocculation tank enters the inclined plate settling tank 18 through the fourth dividing longitudinal plate 10. The polluted landfill leachate stays in the inclined plate settling tank 18 for 30 minutes, and a large amount of pollutants in the landfill leachate enters the precipitated sludge.

[0043] Step 4: After sufficient sedimentation in the inclined plate settling tank 18, the overflow enters the nanofiltration membrane module 19 to remove small molecular substances and ARGs in the landfill leachate. The clear liquid after purification by the nanofiltration membrane enters the clear water tank 21 or the cleaning tank 20. The large particle flocs that cannot pass through the nanofiltration membrane are retained outside the nanofiltration membrane, and the concentrated water enters the concentrated water tank 22. The treatment time of the nanofiltration membrane module 19 is 2.0 h.

[0044] Step 5: The nanofiltration membrane module 19 is cleaned regularly after use, and the cleaning liquid is transported to the nanofiltration membrane module through the backwashing system to backwash the nanofiltration membrane and then transported to the concentrated water tank 22 for storage. The backwashing cycle is 3.5 hours and the backwashing time is 13 minutes.

[0045] Step 6: The pre-sedimentation tank 3, the flocculation tank 29, and the inclined plate sedimentation tank 18 are periodically discharged through the sludge discharge system, and the sludge discharge cycle is 4.5 hours.

[0046] In Example 2, the turbidity of the sample to be purified was 577.0 NTU and the TOC was 637.0 mg / L. The turbidity of the purified water after treatment by the purification system was 0.50 NTU and the TOC was 2.54 mg / L. The turbidity removal rate was 99.91% and the TOC removal rate was 99.60%. The contents of different types of antibiotic resistance genes before and after the purification of the sample to be purified are shown in Table 1. The removal rate of antibiotic resistance genes is shown in Table 1. Figure 2 shown. Table 1 Contents of different types of antibiotic resistance genes in the samples to be purified before and after purification in Example 2:

[0047] .

[0048] Example 3: Take the garbage leachate sample to be purified as shown in Table 2, and use the purification system for removing conventional pollutants and antibiotic resistance genes in garbage leachate of the present invention for purification treatment, which specifically includes the following steps: Step 1: The biologically treated leachate is transported to the pre-sedimentation tank 3 with a liquid inlet flow rate of 50 L / h. It is allowed to stand in the pre-sedimentation tank 3 for 25 minutes to remove a large number of large particle pollutants. The supernatant of the pre-sedimentation tank 3 is injected into the regulating tank 4 through a feed pump.

[0049] Step 2: The landfill leachate after preliminary precipitation in the regulating tank 4 is transported to the flocculation tank of the purification tank through the feed pump, and at the same time, the flocculant is added to the flocculation tank through the flocculant dosing pump, the concentration of the flocculant is 15 g / L, and the dosage of the flocculant is 1.0 g / L; the flocculant shown in the structure of formula 1 is used, wherein x:y=1:9, m1:m2=1:15. The mechanical agitator 6 set in each flocculation chamber is started, the stirring speed of the first flocculation chamber 14 is 250r / min, the stirring speed in the second flocculation chamber 15 is 150r / min, the stirring speed in the third flocculation chamber 16 is 100r / min, and the stirring speed in the fourth flocculation chamber 16 is set to 40r / min to remove conventional pollutants, microorganisms and ARGs in the landfill leachate.

[0050] Step 3: The landfill leachate flocculated in the flocculation tank enters the inclined plate settling tank 18 through the fourth dividing longitudinal plate 10. The polluted landfill leachate stays in the inclined plate settling tank 18 for 25 minutes, and a large amount of pollutants in the landfill leachate enters the precipitated sludge.

[0051] Step 4: After sufficient sedimentation in the inclined plate settling tank 18, the overflow enters the nanofiltration membrane module 19 to remove small molecular substances and ARGs in the landfill leachate. The clear liquid after purification by the nanofiltration membrane enters the clear water tank 21 or the cleaning tank 20. The large particle flocs that cannot pass through the nanofiltration membrane are retained outside the nanofiltration membrane, and the concentrated water enters the concentrated water tank 22. The treatment time of the nanofiltration membrane module 19 is 2.5 hours.

[0052] Step 5: The nanofiltration membrane module 19 is cleaned regularly after use, and the cleaning liquid is transported to the nanofiltration membrane module through the backwashing system to backwash the nanofiltration membrane and then transported to the concentrated water tank 22 for storage. The backwashing cycle is 3.0 hours and the backwashing time is 16 minutes.

[0053] Step 6: The pre-sedimentation tank 3, the flocculation tank 29, and the inclined plate sedimentation tank 18 are periodically discharged through the sludge discharge system, and the sludge discharge cycle is 4.0h.

[0054] In Example 3, the turbidity of the water sample to be purified was 600.2 NTU and the TOC was 676.7 mg / L. The turbidity of the water purified by the purification system was 0.37 NTU and the TOC was 3.28 mg / L. The turbidity removal rate was 99.94% and the TOC removal rate was 99.52%. The contents of different types of antibiotic resistance genes in the water sample before and after purification are shown in Table 2. The removal rate of antibiotic resistance genes is shown in Table 2. Figure 3 shown. Table 2 Contents of different types of antibiotic resistance genes in the samples to be purified before and after purification in Example 3:

[0055] .

[0056] Example 4: The sample to be cleaned as shown in Table 3 is taken and purified by the purification system for removing conventional pollutants and antibiotic resistance genes in garbage leachate of the present invention, which specifically includes the following steps: Step 1: The landfill leachate after biological treatment is transported to the pre-sedimentation tank 3 with a liquid inlet flow rate of 50L / h. It is allowed to stand in the pre-sedimentation tank 3 for 30 minutes to remove a large number of large particle pollutants. The supernatant of the pre-sedimentation tank 3 is injected into the regulating tank 4 through the feed pump.

[0057] Step 2: The landfill leachate after preliminary precipitation in the regulating tank 4 is transported to the flocculation tank of the purification tank through the feed pump, and at the same time, the flocculant is added to the flocculation tank through the flocculant dosing pump, the concentration of the flocculant is 20g / L, and the dosage of the flocculant is 1.2g / L; the flocculant shown in the structure of formula 1 is used, wherein x:y=1:15, m1:m2=1:20. The mechanical agitator 6 set in each flocculation chamber is started, the stirring speed of the first flocculation chamber 14 is 260r / min, the stirring speed in the second flocculation chamber 15 is 160r / min, the stirring speed in the third flocculation chamber 16 is 110r / min, and the stirring speed in the fourth flocculation chamber 16 is set to 50r / min to remove conventional pollutants, microorganisms and ARGs in the landfill leachate.

[0058] Step 3: The landfill leachate flocculated in the flocculation tank enters the inclined plate settling tank 18 through the fourth dividing longitudinal plate 10. The polluted landfill leachate stays in the inclined plate settling tank 18 for 30 minutes, and a large amount of pollutants in the landfill leachate enters the precipitated sludge.

[0059] Step 4: After sufficient sedimentation in the inclined plate settling tank 18, the overflow enters the nanofiltration membrane module 19 to remove small molecular substances and ARGs in the landfill leachate. The clear liquid after purification by the nanofiltration membrane enters the clear water tank 21 or the cleaning tank 20. The large particle flocs that cannot pass through the nanofiltration membrane are retained outside the nanofiltration membrane, and the concentrated water enters the concentrated water tank 22. The treatment time of the nanofiltration membrane module 19 is 3.0 h.

[0060] Step 5: The nanofiltration membrane module 19 is cleaned regularly after use, and the cleaning liquid is transported to the nanofiltration membrane module through the backwashing system to backwash the nanofiltration membrane and then transported to the concentrated water tank 22 for storage. The backwashing cycle is 2.5 hours and the backwashing time is 19 minutes.

[0061] Step 6: The pre-sedimentation tank 3, the flocculation tank 29, and the inclined plate sedimentation tank 18 are periodically discharged through the sludge discharge system, and the sludge discharge cycle is 3.5 hours.

[0062] In Example 4, the turbidity of the water sample to be purified was 650.6 NTU and the TOC was 700.6 mg / L. The turbidity of the water purified by the purification system was 0.42 NTU and the TOC was 3.65 mg / L. The turbidity removal rate was 99.94% and the TOC removal rate was 99.48%. The contents of different types of antibiotic resistance genes in the water sample before and after purification are shown in Table 3. The removal rate of antibiotic resistance genes is shown in Table 3. Figure 4 shown. Table 3 Content of different types of microplastics in the water sample to be purified before and after purification in Example 4:

[0063] .

[0064] Example 5: The sample to be cleaned as shown in Table 4 is taken and purified by the purification system for removing conventional pollutants and antibiotic resistance genes in garbage leachate of the present invention, which specifically comprises the following steps: Step 1: The landfill leachate after biological treatment is transported to the pre-sedimentation tank 3 with a liquid inlet flow rate of 50L / h. It is allowed to stand in the pre-sedimentation tank 3 for 35 minutes to remove a large number of large particle pollutants. The supernatant of the pre-sedimentation tank 3 is injected into the regulating tank 4 through a feed pump.

[0065] Step 2: The landfill leachate after preliminary precipitation in the regulating tank 4 is transported to the flocculation tank of the purification tank through the feed pump, and at the same time, the flocculant is added to the flocculation tank through the flocculant dosing pump, the concentration of the flocculant is 20 g / L, and the dosage of the flocculant is 1.8 g / L; the flocculant shown in the structure of formula 2 is used, wherein a:b=4:1, M1:M2=1:1.4. The mechanical agitator 6 set in each flocculation chamber is started, the stirring speed of the first flocculation chamber 14 is 285r / min, the stirring speed in the second flocculation chamber 15 is 185r / min, the stirring speed in the third flocculation chamber 16 is 135r / min, and the stirring speed in the fourth flocculation chamber 16 is set to 75r / min to remove conventional pollutants, microorganisms and ARGs in the landfill leachate.

[0066] Step 3: The landfill leachate flocculated in the flocculation tank enters the inclined plate settling tank 18 through the fourth dividing longitudinal plate 10. The polluted landfill leachate stays in the inclined plate settling tank 18 for 35 minutes, and a large amount of pollutants in the landfill leachate enters the precipitated sludge.

[0067] Step 4: After sufficient sedimentation in the inclined plate settling tank 18, the overflow enters the nanofiltration membrane module 19 to remove small molecular substances and ARGs in the landfill leachate. The clear liquid after purification by the nanofiltration membrane enters the clear water tank 21 or the cleaning tank 20. The large particle flocs that cannot pass through the nanofiltration membrane are retained outside the nanofiltration membrane, and the concentrated water enters the concentrated water tank 22. The treatment time of the nanofiltration membrane module 19 is 3.5 hours.

[0068] Step 5: The nanofiltration membrane module 19 is cleaned regularly after use, and the cleaning liquid is transported to the nanofiltration membrane module through the backwashing system to backwash the nanofiltration membrane and then transported to the concentrated water tank 22 for storage. The backwashing cycle is 2.0 hours and the backwashing time is 22 minutes.

[0069] Step 6: The pre-sedimentation tank 3, the flocculation tank 29, and the inclined plate sedimentation tank 18 are periodically discharged through the sludge discharge system, and the sludge discharge cycle is 3.0h.

[0070] In Example 5, the turbidity of the water sample to be purified was 667.9 NTU and the TOC was 713.6 mg / L. The turbidity of the water purified by the purification system was 0.88 NTU and the TOC was 5.86 mg / L. The turbidity removal rate was 99.94% and the TOC removal rate was 99.18%. The contents of different types of antibiotic resistance genes in the water sample before and after purification are shown in Table 4. The removal rate of antibiotic resistance genes is shown in Table 4. Figure 5 shown. Table 4 Contents of different types of antibiotic resistance genes in the water samples to be purified before and after purification in Example 5:

[0071] .

[0072] Example 6: The sample to be cleaned as shown in Table 5 is taken and purified by the purification system for removing conventional pollutants and antibiotic resistance genes in garbage leachate of the present invention, which specifically includes the following steps: Step 1: The landfill leachate after biological treatment is transported to the pre-sedimentation tank 3 with an inlet flow rate of 50L / h. It is allowed to stand in the pre-sedimentation tank 3 for 40 minutes to remove a large number of large particle pollutants. The supernatant of the pre-sedimentation tank 3 is injected into the regulating tank 4 through a feed pump.

[0073] Step 2: The landfill leachate after preliminary precipitation in the regulating tank 4 is transported to the flocculation tank of the purification tank through the feed pump, and at the same time, the flocculant is added to the flocculation tank through the flocculant dosing pump, the concentration of the flocculant is 20 g / L, and the dosage of the flocculant is 2.0 g / L; the flocculant shown in the structure of formula 2 is used, wherein a:b=8:1, M1:M2=1:4.14. The mechanical agitator 6 set in each flocculation chamber is started, the stirring speed of the first flocculation chamber 14 is 290r / min, the stirring speed in the second flocculation chamber 15 is 190r / min, the stirring speed in the third flocculation chamber 16 is 140r / min, and the stirring speed in the fourth flocculation chamber 16 is set to 80r / min to remove conventional pollutants, microorganisms and ARGs in the landfill leachate.

[0074] Step 3: The landfill leachate flocculated in the flocculation tank enters the inclined plate settling tank 18 through the fourth dividing longitudinal plate 10. The polluted landfill leachate stays in the inclined plate settling tank 18 for 40 minutes, and a large amount of pollutants in the landfill leachate enters the precipitated sludge.

[0075] Step 4: After sufficient sedimentation in the inclined plate settling tank 18, the overflow enters the nanofiltration membrane module 19 to remove small molecular substances and ARGs in the landfill leachate. The clear liquid after purification by the nanofiltration membrane enters the clear water tank 21 or the cleaning tank 20. The large particle flocs that cannot pass through the nanofiltration membrane are retained outside the nanofiltration membrane, and the concentrated water enters the concentrated water tank 22. The treatment time of the nanofiltration membrane module 19 is 4.0 h.

[0076] Step 5: The nanofiltration membrane module 19 is cleaned regularly after use, and the cleaning liquid is transported to the nanofiltration membrane module through the backwashing system to backwash the nanofiltration membrane and then transported to the concentrated water tank 22 for storage. The backwashing cycle is 1.5 hours and the backwashing time is 25 minutes.

[0077] Step 6: The pre-sedimentation tank 3, the flocculation tank 29, and the inclined plate sedimentation tank 18 are periodically discharged through the sludge discharge system, and the sludge discharge cycle is 2.5 hours.

[0078] In Example 6, the turbidity of the water sample to be purified was 634.9 NTU and the TOC was 634.8 mg / L. The turbidity of the water purified by the purification system was 0.98 NTU and the TOC was 5.45 mg / L. The turbidity removal rate was 99.85% and the TOC removal rate was 99.14%. The contents of different types of antibiotic resistance genes in the water sample before and after purification are shown in Table 5. The removal rate of antibiotic resistance genes is shown in Table 5. Figure 6 shown. Table 5 Contents of different types of antibiotic resistance genes in the water samples to be purified before and after purification in Example 6:

[0079] .

[0080] Example 7: The sample to be cleaned as shown in Table 6 is taken and purified by the purification system for removing conventional pollutants and antibiotic resistance genes in garbage leachate of the present invention, which specifically comprises the following steps: Step 1: The biologically treated leachate is transported to the pre-sedimentation tank 3 with a liquid inlet flow rate of 50 L / h. It is allowed to stand in the pre-sedimentation tank 3 for 45 minutes to remove a large number of large particle pollutants. The supernatant of the pre-sedimentation tank 3 is injected into the regulating tank 4 through a feed pump.

[0081] Step 2: The landfill leachate after preliminary precipitation in the regulating tank 4 is transported to the flocculation tank of the purification tank through the feed pump, and at the same time, the flocculant is added to the flocculation tank through the flocculant dosing pump, the concentration of the flocculant is 20 g / L, and the dosage of the flocculant is 2.5 g / L; the flocculant shown in the structure of formula 2 is used, wherein a:b=12:1, M1:M2=1:6.90. The mechanical agitator 6 set in each flocculation chamber is started, the stirring speed of the first flocculation chamber 14 is 300r / min, the stirring speed in the second flocculation chamber 15 is 200r / min, the stirring speed in the third flocculation chamber 16 is 150r / min, and the stirring speed in the fourth flocculation chamber 16 is set to 90r / min to remove conventional pollutants, microorganisms and ARGs in the landfill leachate.

[0082] Step 3: The landfill leachate flocculated in the flocculation tank enters the inclined plate settling tank 18 through the fourth dividing longitudinal plate 10. The polluted landfill leachate stays in the inclined plate settling tank 18 for 45 minutes, and a large amount of pollutants in the landfill leachate enters the precipitated sludge.

[0083] Step 4: After sufficient sedimentation in the inclined plate settling tank 18, the overflow enters the nanofiltration membrane module 19 to remove small molecular substances and ARGs in the landfill leachate. The clear liquid after purification by the nanofiltration membrane enters the clear water tank 21 or the cleaning tank 20. The large particle flocs that cannot pass through the nanofiltration membrane are retained outside the nanofiltration membrane, and the concentrated water enters the concentrated water tank 22. The treatment time of the nanofiltration membrane module 19 is 4.5 hours.

[0084] Step 5: The nanofiltration membrane module 19 is cleaned regularly after use, and the cleaning liquid is transported to the nanofiltration membrane module through the backwashing system to backwash the nanofiltration membrane and then transported to the concentrated water tank 22 for storage. The backwashing cycle is 1.0h and the backwashing time is 28min.

[0085] Step 6: The pre-sedimentation tank 3, the flocculation tank 29, and the inclined plate sedimentation tank 18 are periodically discharged through the sludge discharge system, and the sludge discharge cycle is 2.0h.

[0086] In Example 7, the turbidity of the water sample to be purified was 656.7 NTU and the TOC was 667.7 mg / L. The turbidity of the water purified by the purification system was 0.99 NTU and the TOC was 5.76 mg / L. The turbidity removal rate was 99.85% and the TOC removal rate was 99.14%. The contents of different types of antibiotic resistance genes in the water sample before and after purification are shown in Table 6. The removal rate of antibiotic resistance genes is shown in Table 6. Figure 7 shown. Table 6 Contents of different types of antibiotic resistance genes in the water samples to be purified before and after purification in Example 7:

[0087] .

[0088] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A purification system for removing conventional pollutants and antibiotic resistance genes from landfill leachate, characterized in that: The purification system includes: A pre-sedimentation tank (3), the upper part of which is connected to the regulating tank (4) via a conveying pipeline; A purification tank, the purification tank comprising a flocculation tank (29) and an inclined plate sedimentation tank (18) which are adjacently connected and arranged, and the flocculation tank is connected to the regulating tank (4) through a conveying pipeline; A nanofiltration membrane assembly (19), wherein a liquid inlet end of the nanofiltration membrane assembly (19) is connected to an overflow pipe of the inclined plate sedimentation tank; A clear water tank (21), wherein the clear water tank (21) is connected to a water outlet of the nanofiltration membrane assembly (19); A concentrated water pool (22), wherein the concentrated water pool (22) is connected to one water outlet end of the nanofiltration membrane module (19); A backwashing system, wherein the backwashing system is connected to the water outlet of the nanofiltration membrane module and backwashes the nanofiltration membrane module (19).

2. The purification system for removing conventional pollutants and antibiotic resistance genes from landfill leachate according to claim 1, characterized in that: The flocculation tank is separated into four flocculation chambers along its flow direction by three partition longitudinal plates, and the opening ends of two adjacent partition longitudinal plates are arranged alternately; a flocculant storage tank (5) is arranged above the flocculation tank, and the flocculant mother liquid enters the flocculation tank through a feed pump and a feed valve, and a mechanical stirrer is arranged in each of the four flocculation chambers; The lower end opening of the first longitudinal partition plate (7), the upper end opening of the second longitudinal partition plate (8), and the lower end opening of the third longitudinal partition plate (9) are respectively a liquid outlet and an overflow outlet for the liquid phase to pass through; The flocculation tank and the inclined plate sedimentation tank (18) are separated by a fourth dividing longitudinal plate (10); an upper end opening of the fourth dividing longitudinal plate (10) forms an overflow port for supernatant from the flocculation tank to overflow into the inclined plate sedimentation tank (18); a plurality of dividing inclined plates (12) are arranged in the inclined plate sedimentation tank (18) with an angle of 50 to 70 degrees to the horizontal plane.

3. The purification system for removing conventional pollutants and antibiotic resistance genes from landfill leachate according to claim 1, characterized in that: The bottoms of the pre-sedimentation tank (3), the flocculation tank 29 and the inclined plate sedimentation tank (18) are all provided with mud discharge ports (24) and mud discharge branch pipes connected to the mud discharge ports (24); the plurality of mud discharge branch pipes are respectively connected to a mud discharge main pipe (25), and each mud discharge branch pipe is connected to a mud discharge valve (27); and the mud discharge cycle is 2 to 5 hours.

4. The purification system for removing conventional pollutants and antibiotic resistance genes from landfill leachate according to claim 1, characterized in that: The nanofiltration membrane assembly (19) is composed of a plurality of ultrafiltration and nanofiltration membranes connected in parallel; the nanofiltration membrane assembly (19) is a hollow fiber membrane, a roll-type membrane or a tubular membrane; and its material is a polyamide composite membrane, polyamide, polypropylene, polyether sulfone, or polyvinyl alcohol.

5. The purification system for removing conventional pollutants and antibiotic resistance genes from landfill leachate according to claim 4, characterized in that: The pore size of the ultrafiltration nanofiltration membrane is 200-1000 Daltons, which is between the pore size of ultrafiltration and reverse osmosis; the operating pressure of the nanofiltration membrane assembly (19) is 0.2-1.0 MPa.

6. The purification system for removing conventional pollutants and antibiotic resistance genes from landfill leachate according to claim 1, characterized in that: The backwashing system comprises a cleaning tank (20), the cleaning tank (20) being connected to a water outlet of a nanofiltration membrane module (19) via a delivery pipeline, and a backwashing pump (23) being connected to the delivery pipeline; the backwashing cycle of the nanofiltration membrane module (19) is 1.0 to 4.0 hours, and the backwashing time each time is 10 to 30 minutes.

7. A method for removing conventional pollutants and antibiotic resistance genes from landfill leachate, characterized in that: The purification system according to any one of claims 1 to 6 comprises the following steps: Step 1: The landfill leachate after biological treatment is transported to a pre-sedimentation tank (3), where it is allowed to stand to remove a large number of large particle pollutants, and the supernatant of the pre-sedimentation tank (3) is injected into a regulating tank (4) through a feed pump; Step 2: The landfill leachate that has undergone preliminary sedimentation in the regulating tank (4) is transported to the flocculation tank of the purification tank through a feed pump, and at the same time, a flocculant is added to the flocculation tank through a flocculant dosing pump, and a mechanical agitator (6) provided in each flocculation chamber is started to allow the flocculant to fully react with the landfill leachate to remove conventional pollutants, microorganisms and ARGs in the landfill leachate; Step 3: the landfill leachate flocculated in the flocculation tank enters the inclined plate settling tank (18) through the fourth dividing longitudinal plate (10), and a large amount of pollutants in the landfill leachate enter the precipitated sludge; Step 4: After sufficient sedimentation in the inclined plate settling tank (18), the overflow enters the nanofiltration membrane group (19) to remove small molecular substances and ARGs in the landfill leachate. The clear liquid purified by the nanofiltration membrane enters the clear water tank (21) or the cleaning tank (20). The large particle flocs that cannot pass through the nanofiltration membrane are retained outside the nanofiltration membrane and the concentrated water enters the concentrated water tank (22). The treatment time of the nanofiltration membrane group (19) is 1.5~4.5 hours; Step 5: The nanofiltration membrane module (19) is cleaned regularly after use, and the cleaning liquid is transported to the nanofiltration membrane module through the backwashing system to backwash the nanofiltration membrane and then transported to the concentrated water tank (22) for storage; Step 6: The pre-sedimentation tank (3), the flocculation tank (29), and the inclined plate sedimentation tank (18) are periodically discharged through the sludge discharge system.

8. The method for removing conventional pollutants and antibiotic resistance genes from garbage leachate according to claim 7, characterized in that: The flocculant in step 2 is a chitosan-based flocculant, and its structural formula is shown in Formula 1 and Formula 2: (1)； In formula 1: poly N-n-propyl acrylamide, poly N-isopropyl acrylamide and polyacryloylpiperidine are grafted onto chitosan, respectively, wherein x:y is a molar ratio, the value range of x:y= is 1:(3-15), and the mass ratio of chitosan monomer to substance R is defined as m1:m2, and the value range is 1:(5-20); (2)； In formula 2: n is the average degree of polymerization, the value range of a:b is (4~12):1, and the mass ratio of Al hydroxide to R M1:M2 is 1: (1.38~6.90).

9. The method for removing conventional pollutants and antibiotic resistance genes from garbage leachate according to claim 8, characterized in that: The concentration of the flocculant added in step 2 is 1-3 g / L; the stirring speed in the first flocculation chamber (14) is 250-300 r / min, the stirring speed in the second flocculation chamber (15) is 150-200 r / min, the stirring speed in the third flocculation chamber (16) is 100-150 r / min, and the stirring speed in the fourth flocculation chamber (17) is 40-90 r / min.

10. The method for removing conventional pollutants and antibiotic resistance genes from garbage leachate according to claim 7, characterized in that: The flocculated solution flowing out of the flocculation tank (29) in step 3 stays in the inclined plate settling tank (18) for 15 to 45 minutes.

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