Treatment system for removing resistance genes in sewage and application of treatment system

Abstract

The invention belongs to the technical field of sewage treatment, and particularly relates to a treatment system for removing resistance genes in sewage and application of the treatment system. The device comprises a first treatment unit, a second treatment unit and a third treatment unit which are sequentially connected, wherein a water inlet of the first treatment unit is connected with tail water of a sewage plant; the first treatment unit is connected with the ozone generator and is used for treating intracellular antibiotic resistance genes; the second treatment unit is connected with the nuclease adding device and is used for treating extracellular antibiotic resistance genes; the third treatment unit is connected with a sodium hypochlorite dosing device, and the first treatment unit is connected with the third treatment unit through a tail gas recoverer and is used for inactivating microorganisms. By arranging the first processing unit and the second processing unit, the extracellular resistance gene and the intracellular resistance gene can be respectively processed, the nuclease is concentrated by adopting PAM, the purity of the nuclease is improved, and the processing efficiency of the intracellular resistance gene is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a treatment system for removing resistance genes in sewage and an application thereof. Background Art

[0002] Antibiotics are one of the most important medical discoveries. They have played a huge role in controlling human infectious diseases and are also playing an irreplaceable role in medical treatment, livestock and poultry, and aquaculture. However, due to the extensive use and abuse of antibiotics, genes encoding antibiotic resistance in microorganisms are selectively enriched in the environment. Pathogenic bacteria acquire antibiotic resistance genes through gene mutation or horizontal gene transfer, resulting in the failure of antibiotic treatment, prolonged treatment time, and increased mortality, posing a severe challenge to human and animal health and the ecological environment.

[0003] The rapid development of bacterial antibiotic resistance has accelerated the emergence and spread of multidrug-resistant bacteria (ARBs) and antibiotic resistance genes (ARGs). ARGs are the genetic determinants of antibiotic resistance in microorganisms. They have the ability to persist in the environment and spread between different media, greatly increasing the risk of human infection with pathogenic bacteria.

[0004] ARGs in the environment mainly exist in the form of intracellular DNA and extracellular DNA. Intracellular antibiotic resistance genes (iARGs) mainly exist on chromosomes or mobile genetic elements in ARBs, and extracellular antibiotic resistance genes (eARGs) generally exist on mobile genetic elements in the environment or are exposed in environmental media. Intracellular resistance genes promote the proliferation of ARBs through conjugation and transduction, while extracellular resistance genes are often absorbed by bacteria through transformation, thereby promoting the spread of antibiotic resistance genes.

[0005] It should be pointed out that the relative proportions of different forms of ARGs in the environment are changing dynamically. On the one hand, iARGs can be released into the extracellular environment through the lysis of dead cells or the secretion of living cells, and exist in the environment in the form of eARGs; on the other hand, eARGs in the environment can also enter the cell through transformation and become iARGs.

[0006] At present, the removal methods for ARGs mainly involve physical methods (such as coagulation, etc.), chemical methods (such as oxidation, Fenton, photocatalysis, etc.), physical-chemical combined methods (such as UV radiation, ionizing radiation, etc.), and biological methods (such as membrane bioreactors and artificial wetlands, etc.). Among them, physical and biological methods can only remove ARGs in the target water body, but cannot completely eliminate ARGs. They may also enrich all ARGs into sludge and increase the abundance of ARGs in sludge. Ozone oxidation technology is widely used in chemical methods, and ozone oxidation technology can simultaneously degrade intracellular antibiotic resistance genes and intracellular antibiotic resistance genes. However, although ozone oxidation technology is efficient and fast, it has a large investment, resulting in high cost of use, and is not suitable for small-scale (1000m 3 / d or less) in the integrated treatment of resistance genes in wastewater. Summary of the invention

[0007] In order to overcome the defects in the prior art, the present invention provides a treatment system for removing resistance genes in sewage and its application. The present invention can effectively remove extracellular antibiotic resistance genes and intracellular antibiotic resistance genes in small-scale wastewater at a low cost.

[0008] To achieve one of the above purposes, the present invention adopts the following technical solution:

[0009] A treatment system for removing resistance genes in sewage, the device comprises a first treatment unit, a second treatment unit and a third treatment unit which are connected in sequence, the water inlet of the first treatment unit is connected to the tail water of the sewage plant; the first treatment unit is connected to an ozone generator for treating intracellular antibiotic resistance genes; the second treatment unit is connected to a nuclease dosing device for treating extracellular antibiotic resistance genes; the third treatment unit is connected to a sodium hypochlorite dosing device, and the first treatment unit is connected to the third treatment unit through a tail gas recovery device for inactivating microorganisms.

[0010] Preferably, several layers of honeycomb iron-based fillers are further provided in the first processing unit, and several titanium disc aeration heads are provided at the bottom of the first processing unit, and the titanium disc aeration heads are located at the bottom ends of the iron-based fillers.

[0011] Preferably, the nuclease in the nuclease dosing device is a concentrated nuclease, and the concentration method is: dissolving PAM in water to form a solution with a mass concentration of 3‰, taking the extracellular secretory nuclease, and placing it in a 3‰ PAM solution to obtain a mixed solution, the volume ratio of the nuclease to the 3‰ PAM solution is 1:10, and finally using an MBR membrane to filter the mixed solution to obtain concentrated nuclease.

[0012] Preferably, the device further comprises a fourth processing unit, in which the ozone generator, the nuclease dosing device and the sodium hypochlorite dosing device are all arranged, and the first processing unit, the second processing unit, the third processing unit and the fourth processing unit are an integrated structure; the water treatment volume of the device is ≤1000m 3 / d.

[0013] Preferably, the device processes water at a rate of 500 m 3 / d, the volume of the first processing unit is 10.5m 3 The volume of the second processing unit is 60m 3 The volume of the third processing unit is 15m 3 .

[0014] Preferably, the nuclease dosing device is connected to the second processing unit via a resistance gene detection device.

[0015] Preferably, the first processing unit is a closed structure, and an inspection hole and an observation hole are reserved on the first processing unit.

[0016] Preferably, a pressure gauge is provided on the branch pipe of the titanium disc aeration head, and the branch pipe of the titanium disc aeration head is connected to the backwashing device.

[0017] S1. Introduce the tail water of the sewage treatment plant into the first treatment unit, turn on the ozone generator, titanium plate aeration head and tail gas recovery device, and the tail water will flow into the second treatment unit after staying in the first treatment unit for 30 minutes;

[0018] S2. Turn on the nuclease dosing device and the resistance gene detection device. The tail water flows into the third treatment unit after staying in the second treatment unit for 170 minutes. Turn on the sodium hypochlorite dosing device. The tail water is discharged after staying in the third treatment unit for 43 minutes.

[0019] Preferably, in step S1, the ozone generated by the ozone generator stays in the first treatment unit for a period of 15≤h≤30min, and the concentration of the ozone is 5-10mg / L.

[0020] The advantages of the present invention are:

[0021] (1) The present invention can treat the extracellular antibiotic resistance genes and intracellular antibiotic resistance genes in small-scale wastewater separately by setting up a first treatment unit and a second treatment unit, and use PAM to concentrate nuclease to improve the purity of nuclease, thereby further improving the treatment efficiency of intracellular antibiotic resistance genes; the use cost can be effectively reduced by separate treatment; and the excess ozone in the first treatment unit is collected and reused through the tail gas recovery device, thereby improving the utilization rate of ozone and avoiding waste of resources.

[0022] (2) The ozone inlet pipe provided in the present invention can introduce ozone into the treatment pool. The multi-layer honeycomb iron-based filler provided can increase the contact area between the iron base and ozone, promote the decomposition of ozone, and form hydroxyl free radicals with strong oxidizing effect. Under the same treatment effect, the amount of ozone used can be reduced by about 40%, which greatly improves the wastewater treatment efficiency of ozone; the exhaust gas collector provided can collect overflowed ozone, so that the ozone can be fully utilized; the titanium disk aeration head provided can evenly disperse the ozone in the wastewater, further improving the treatment efficiency of ozone. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the present invention.

[0024] The meanings of the symbols in the figure are as follows:

[0025] 1-first treatment unit, 11-iron-based filler, 12-titanium disc aeration head, 13-exhaust gas recovery device, 2-second treatment unit, 3-third treatment unit, 4-fourth treatment unit, 41-ozone generator, 42-nuclease dosing device, 43-sodium hypochlorite dosing device, 5-resistance gene detection device. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0027] like Figure 1 As shown, a treatment system for removing resistance genes in sewage includes a rectangular shell, which is divided into four units, including a first treatment unit 1, a second treatment unit 2, a third treatment unit 3 and a fourth treatment unit 4 connected in sequence. The first treatment unit 1 is an intracellular antibiotic resistance gene treatment unit, the second treatment unit 2 is an extracellular antibiotic resistance gene treatment unit, and the third treatment unit 3 is a microbial inactivation unit. The first treatment unit 1 includes an inlet pipe and an outlet hole, the outlet hole is connected to the second treatment unit 2, and the outlet water enters the second treatment unit 2. The first treatment unit 1 is provided with an intake pipe and an exhaust pipe, the exhaust pipe is provided to be connected to the exhaust gas recovery device 13, the exhaust end of the exhaust gas recovery device 13 is connected to the third treatment unit 3, the exhaust gas is connected to the third treatment unit 3, and the remaining effective gas in the exhaust gas is recycled. A gas flow meter and an electric valve are provided in the intake pipe to adjust the intake volume according to the amount of water treated and the removal of pollutants.

[0028] Specifically, since the gas entering the first processing unit 1 is ozone, which is highly corrosive and harmful to the human body at high concentrations, the first processing unit 1 needs to be fully sealed to prevent gas overflow. However, an inspection hole is reserved on the top of the first processing unit 1 and an observation hole is reserved on the side to facilitate repair and observation.

[0029] A titanium disc aeration head 12 is arranged at the bottom of the first treatment unit 1, and a pressure gauge is arranged on the branch pipe of the titanium disc aeration head 12, and the branch pipe of the titanium disc aeration head 12 is connected to the backwashing device. When the titanium disc aeration head 12 is blocked, resulting in an increase in pressure, the backwashing device can be opened to backwash the titanium disc aeration head 12. The middle part of the first treatment unit 1 is provided with three layers of iron-based fillers 11, which are upper, middle and lower. The iron-based fillers 11 have a honeycomb structure and are used to improve the efficiency of ozone treatment. The ozone saving can reach 40%. The height of the three layers of iron fillers 11 accounts for 2 / 3 of the height of the entire shell. Each layer of iron fillers 11 can be moved back and forth to form a three-dimensional space filler. During normal operation, the iron fillers 11 are all immersed in the sewage. If the iron fillers 11 are blocked or the water quality is good, any layer of iron fillers 11 can be removed at any time as needed for cleaning or standby. The arrangement of the iron fillers 11 that can be moved above and below the liquid surface reduces the degree of blockage of the iron-based catalyst and prolongs the service life.

[0030] The wastewater tailwater is oxidized by ozone in the first treatment unit 1, which can significantly inhibit the horizontal transfer of intracellular antibiotic resistance genes by regulating the expression of related genes such as SOS response, membrane osmotic regulation, cell-to-cell contact, and ATP. At the same time, some cells can be lysed, and some resistance genes can be transferred to the extracellular part, which can be absorbed by bacteria through transformation together with the original extracellular resistance genes, thereby promoting the spread of antibiotic resistance genes. In order to prevent the spread of resistance genes, extracellular antibiotic resistance genes also need to be removed simultaneously.

[0031] Furthermore, the second processing unit 2 is connected to the nuclease dosing device 42 for processing the extracellular antibiotic resistance gene. The nuclease in the nuclease dosing device 42 is a concentrated and purified nuclease, wherein the specific steps of the method for purifying the nuclease are as follows:

[0032] Dissolve PAM (flocculant) in water to form a solution with a mass concentration of 3‰, take the extracellular secretory nuclease, and place it in the 3‰ PAM solution to obtain a mixed solution, the volume ratio of nuclease to 3‰ PAM solution is 1:10, and finally use MBR membrane to filter the mixed solution to obtain concentrated nuclease. After filtration, the concentration of nuclease increases by more than 10 times, and the nuclease is used after the concentrated solution is purified.

[0033] The second processing unit 2 adopts a nuclease in vitro secretion system, and designs and constructs nucleases through gene editing and synthetic biology technology. At the same time, the nuclease is concentrated using PAM. The higher the nuclease concentration, the better the effect of removing resistance genes. The added nuclease adopts an automatic feedback system, and the resistance gene detection device 5 is connected to the water outlet of the third processing unit 3 to monitor the concentration of resistance genes (removal rate is more than 80%). Through dynamic correction of historical and real-time data, the most significant disturbance and control variables for removing resistance genes and the correlation between the amount of nuclease added and the efficiency of resistance gene removal are found, and finally the highest efficiency range of agent addition under different working conditions is given. Combined with the results of the sensitivity analysis of the mechanism model, the processing load is dynamically identified to solve the optimal agent dosage at the current moment.

[0034] Bacteria produce a variety of enzymes, and nuclease is an important one among them. There are many types of nucleases, including endonuclease I, which can catalyze the degradation of DNA. As a natural biocatalyst, nuclease has high specificity and efficient gene cleavage ability, and can effectively degrade antibiotic resistance genes. Bacteria that can secrete nucleases extracellularly are selected for cultivation and reproduction, and their nutrient source is high-concentration sodium acetate, a carbon source commonly used in sewage treatment plants.

[0035] Furthermore, the third treatment unit 3 is a microorganism inactivation unit, the third treatment unit 3 is connected to the sodium hypochlorite dosing device 43, and the first treatment unit 1 is connected to the third treatment unit 3 through the tail gas recovery device 13, and the inactivation is carried out by combining sodium hypochlorite + ozone. The ozone comes from the excess ozone of the first treatment unit 1 collected by the tail gas recovery device 13, which improves the use efficiency of ozone and reduces operating costs.

[0036] The system of the present invention integrates the first processing unit 1, the second processing unit 2, the third processing unit 3 and the fourth processing unit 4 into an integrated device, which saves space. The device adopts a modular design, which is convenient for production, on-site installation and debugging.

[0037] An application of a treatment system for removing resistance genes in sewage comprises the following steps:

[0038] S1, introducing tail water from the sewage treatment plant into the first treatment unit 1, turning on the ozone generator 41, the titanium disc aeration head 12 and the tail gas recovery device 13, and the tail water flows into the second treatment unit 2 after passing through the first treatment unit 1;

[0039] S2. Turn on the nuclease dosing device 42 and the resistance gene detection device 5. The tail water flows into the third treatment unit 3 after passing through the second treatment unit 2. Turn on the sodium hypochlorite dosing device 43. The tail water flows through the third treatment unit 3 and is discharged.

[0040] The residence time of the tail water in the first treatment unit 1, the second treatment unit 2, and the third treatment unit 3 are 30 min, 170 min, and 43 min, respectively, and the time can be adjusted according to the resistance gene concentration.

[0041] In step S1, the ozone generated by the ozone generator 41 stays in the first treatment unit 1 for 15min≤h≤30min, and the concentration of ozone is 5-10mg / L, and the ozone oxidation is controlled to the enzyme required for oxidative decomposition of glucose inside bacteria, so that the bacteria are inactivated and killed. After the bacteria die, the intracellular resistance genes are secreted into the extracellular space, and the extracellular resistance genes are degraded by nuclease, effectively reducing the abundance of antibiotic resistance genes.

[0042] The first treatment unit 1, the second treatment unit 2 and the third treatment unit 3 are designed in series, and the fourth treatment unit 4 can be set at the front end or the rear end according to the equipment conditions. 3 / d, 24 hours of continuous treatment, the volume of the first treatment unit is 10.5m 3 The volume of the second processing unit is 60m 3 The volume of the third processing unit is 15m 3 .

[0043] The removal effect of the extracellular antibiotic resistance gene and the intracellular antibiotic resistance gene of the invention is as high as over 98%.

[0044] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A treatment system for removing resistance genes in sewage, characterized in that: The device comprises a first treatment unit (1), a second treatment unit (2) and a third treatment unit (3) which are connected in sequence, wherein the water inlet of the first treatment unit (1) is connected to tail water of a sewage treatment plant; the first treatment unit (1) is connected to an ozone generator (41) for treating intracellular antibiotic resistance genes; the second treatment unit (2) is connected to a nuclease dosing device (42) for treating extracellular antibiotic resistance genes; the third treatment unit (3) is connected to a sodium hypochlorite dosing device (43), and the first treatment unit (1) is connected to the third treatment unit (3) via a tail gas recovery device (13) for inactivating microorganisms.

2. A treatment system for removing resistance genes in sewage according to claim 1, characterized in that: A plurality of layers of honeycomb-shaped iron-based fillers (11) are also provided in the first processing unit (1), and a plurality of titanium disc aeration heads (12) are provided at the bottom of the first processing unit (1), and the titanium disc aeration heads (12) are located at the bottom end of the iron-based fillers (11).

3. A treatment system for removing resistance genes in sewage according to claim 1, characterized in that: The nuclease in the nuclease dosing device (42) is a concentrated nuclease, and the concentration method is: dissolving PAM in water to form a solution with a mass concentration of 3‰, taking the extracellular secretory nuclease, and placing it in the 3‰ PAM solution to obtain a mixed solution, the volume ratio of the nuclease to the 3‰ PAM solution is 1:10, and finally using an MBR membrane to filter the mixed solution to obtain the concentrated nuclease.

4. A treatment system for removing resistance genes in sewage according to claim 1, characterized in that: The device further comprises a fourth processing unit (4), wherein the ozone generator (41), the nuclease dosing device (42) and the sodium hypochlorite dosing device (43) are all arranged in the fourth processing unit (4), and the first processing unit (1), the second processing unit (2), the third processing unit (3) and the fourth processing unit (4) are an integrated structure; the water treatment volume of the device is ≤1000m 3 / d.

5. A treatment system for removing resistance genes in sewage according to claim 1, characterized in that: The water treatment capacity of the device is 500m 3 / d, the volume of the first treatment unit (1) is 10.5m 3 The volume of the second processing unit (2) is 60m 3 The volume of the third processing unit (3) is 15m 3 .

6. A treatment system for removing resistance genes in sewage according to claim 1, characterized in that: The nuclease dosing device (42) is connected to the second processing unit (2) via the resistance gene detection device (5).

7. A method for removing resistance genes in sewage according to claim 1, characterized in that: The first processing unit (1) is a closed structure, and an inspection hole and an observation hole are reserved on the first processing unit (1).

8. A method for removing resistance genes in sewage according to claim 1, characterized in that: A pressure gauge is provided on the branch pipe of the titanium disc aeration head (12), and the branch pipe of the titanium disc aeration head (12) is connected to a backwashing device.

9. An application of a treatment system for removing resistance genes in sewage as claimed in any one of claims 1 to 8, characterized in that: The steps include: S1, introducing tail water from the sewage treatment plant into the first treatment unit (1), turning on the ozone generator (41), the titanium disc aeration head (12) and the tail gas recovery device (13), and the tail water flows into the second treatment unit (2) after passing through the first treatment unit (1); S2, the nuclease dosing device (42) and the resistance gene detection device (5) are turned on, the tail water flows into the third treatment unit (3) after passing through the second treatment unit (2), the sodium hypochlorite dosing device (43) is turned on, and the tail water flows into the third treatment unit (3) after passing through the third treatment unit (3).

10. Use of the treatment system for removing resistance genes in sewage according to claim 9, characterized in that: In step S1, the ozone generated by the ozone generator (41) stays in the first treatment unit (1) for a period of 15≤h≤30min, and the concentration of the ozone is 5-10mg / L.

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