Low-pressure ultrafiltration sewage treatment method based on bioelectrochemical enhancement, device and application

Abstract

The application belongs to the technical field of wastewater treatment and resource utilization, and relates to a low-pressure ultrafiltration wastewater treatment method based on bioelectrochemical enhancement, a device and application. The treatment device is composed of a water inlet tank, a constant water level tank, a cathode, a resistor, a membrane assembly, a biological filter cake layer, a pre-filtering layer-anode, an ultrafiltration membrane, a water collecting device, a data acquisition module and a computer. The treatment device is used for treating effluent from a secondary sedimentation tank of a sewage treatment plant and livestock and poultry breeding wastewater tail water; on the basis of reserving nitrogen and phosphorus resources, deep removal of heavy metals and antibiotics is realized, and the spread of antibiotic resistance genes is inhibited, so that the nitrogen and phosphorus resources in the effluent from the sewage treatment plant and the livestock and poultry breeding wastewater tail water can be safely reused. In the application, the low-pressure ultrafiltration realizes continuous flow filtration by using the transmembrane pressure difference generated by gravitational potential energy, and the coupled bioelectrochemistry realizes reduction of heavy metals and deep removal of antibiotics by using the electric energy generated by biodegradation of organic matter, so that the method has the advantages of greenness, low carbon and sustainability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater treatment and resource utilization, and particularly relates to a low-pressure ultrafiltration wastewater treatment method and device based on bioelectrochemical reinforcement, which can be used for deep treatment of effluent from a wastewater treatment plant and tail water of livestock and poultry breeding wastewater, and the treated water can retain nitrogen and phosphorus resources, has extremely low energy consumption, can effectively remove heavy metals, antibiotics and pathogens, and reduce the risk of resistance gene transmission, and can be used for agricultural irrigation. BACKGROUND

[0002] Current processes such as anaerobic digestion and activated sludge method can effectively reduce conventional pollutants such as chemical oxygen demand (COD) and biological oxygen demand (BOD5), but the heavy metals and pathogens in the effluent can easily exceed the limit values in the Agricultural Irrigation Water Quality Standard. Among them, the exceeding standard rate of Cu 2+ and Zn 2+ can reach 23.75%-73.9%, and 76.5% of the effluent has the problem of exceeding the standard of Escherichia coli. In addition, the concentration of antibiotics in the effluent is relatively high, such as tetracycline antibiotics (TCs) reaching 388.02 μg / L and sulfonamide antibiotics (SAs) reaching 21.24 μg / L. Moreover, heavy metal-antibiotic combined pollution can enhance selective pressure to cause the abundance of antibiotic resistance genes (ARGs) to increase, and direct reuse of agriculture will cause soil-crop system pollution and public health risks.

[0003] Existing deep treatment technologies, such as constructed wetlands, can improve the removal rate of heavy metals and antibiotics, but the problems of residual pathogens such as fecal coliform bacteria and ARGs enrichment are prominent. Membrane bioreactors can effectively remove pathogens through interception, but their high-pressure operation mode has high energy consumption and serious membrane pollution, which restricts large-scale application. At the same time, heavy metals in existing deep treatment technologies are mainly removed by adsorption and interception, without changing themselves, while the combined pollution of heavy metals and antibiotics can increase the selective pressure to cause the abundance of ARGs to increase, increasing the risk of transmission.

[0004] Research has found that low-pressure ultrafiltration can achieve long-term stability of flux depending on microorganisms, but the accumulation of heavy metals and antibiotics in the biological filter cake layer can bring toxicity to microorganisms, inhibit microbial activity, and aggravate membrane pollution, thereby affecting the flux. Therefore, there is an urgent need to develop a new low-pressure ultrafiltration wastewater treatment device and method based on bioelectrochemical reinforcement to effectively solve the above problems. SUMMARY

[0005] The application aims to provide a low-pressure ultrafiltration sewage treatment method and device coupled with a bioelectrochemical strategy.

[0006] The application aims to provide a low-pressure ultrafiltration sewage treatment method and device coupled with a bioelectrochemical strategy.

[0007] A low-pressure ultrafiltration sewage treatment method based on bioelectrochemical reinforcement comprises the following steps:

[0008] A, water in the water inlet tank 1 enters the constant water level tank 2;

[0009] B, the float ball valve and the water level sensor of the constant water level tank 2 control the liquid level difference between the liquid surface of the constant water level tank 2 and the ultrafiltration membrane 8 to be kept at 0.2-1.0 bar;

[0010] C, the pre-filtering layer-anode 7 is laid on the ultrafiltration membrane 8 after being inoculated, and the biological filter cake layer 6 formed thereon removes organic matter and antibiotics through biological action; the biological filter cake layer 6, the pre-filtering layer-anode 7 and the ultrafiltration membrane 8 adsorb and intercept heavy metals, pathogens and other substances;

[0011] D, the microorganisms in the biological filter cake layer 6 can produce electrons through the degradation of organic matter and antibiotics, which are transmitted to the cathode 3 through an external circuit, and the heavy metals are further removed through reduction at the cathode 3;

[0012] E, due to the effective removal of heavy metals at the cathode 3 and the reinforced removal of antibiotics at the pre-filtering layer-anode 7, the accumulation of heavy metals and antibiotics in the biological filter cake layer 6 is reduced, thereby reducing the heavy metal-antibiotic selective pressure and the generation and spread risk of ARGs;

[0013] F, the water in the constant water level tank 2 flows out after passing through the biological filter cake layer 6, the pre-filtering layer-anode 7 and the ultrafiltration membrane 8, and is collected in the water collecting device 9.

[0014] A low-pressure ultrafiltration sewage treatment device based on bioelectrochemical reinforcement comprises a water inlet tank 1, a constant water level tank 2, a cathode 3, a resistor 4, a membrane assembly 5, a biological filter cake layer 6, a pre-filtering layer-anode 7, an ultrafiltration membrane 8, a water collecting device 9, a data acquisition module 10 and a computer 11.

[0015] The water inlet tank 1 is provided with sewage collected from the secondary sedimentation tank of a sewage plant and livestock and poultry breeding wastewater tail water, and the bottom of the water inlet tank 1 is connected to a constant water level tank 2 through a pipeline provided with a stop valve; the constant water level tank 2 is provided with a cathode 3, and the cathode 3 is connected to a pre-filtering layer-anode 7 in a membrane module 5 through an electric wire via a resistor 4; the bottom of the constant water level tank 2 is connected to the top of the membrane module 5 through a connecting pipeline, and a stop valve is arranged on the connecting pipeline; the pre-filtering layer-anode 7 is directly laid above an ultrafiltration membrane 8, and a biological filter cake layer 6 is arranged above the pre-filtering layer-anode 7.

[0016] The membrane module 5 is provided with an operating pressure of 0.2-1.0 bar by water depth, and a gravity potential corresponding to the water head is used to realize a transmembrane pressure difference for continuous flow filtration; the side of the membrane module 5 is connected to a water collecting device 9 through a connecting pipeline, and a stop valve is also arranged on the connecting pipeline; the data acquisition module 10 is used to measure the voltage between the two ends of the resistor 4; and a computer 11 is used to collect the voltage data collected by the data acquisition module 10 and to monitor the bioelectrochemical performance in real time.

[0017] Further, the constant water level tank 2 is provided with a float ball valve and a water level sensor, so as to control the amount of water flowing from the water inlet tank 1 to the constant water level tank 2, and to keep the liquid level difference between the constant water level tank 2 and the ultrafiltration membrane 8 constant.

[0018] Further, the cathode 3 is fixed at a position submerged in the liquid in the constant water level tank 2.

[0019] Further, the cathode 3 is made of a carbon-based material, including carbon paper, carbon felt, carbon rod, carbon fiber sheet, carbon brush, carbon foam, graphite plate, graphite rod, graphite sheet, graphite cloth, graphite particle, activated carbon and reticular glassy carbon.

[0020] Further, the resistor 4 is a 100-1000 ohm resistor.

[0021] Further, the biological filter cake layer 6 is composed of initial inoculated organisms, filtered and retained organisms and proliferated organisms, and substances retained by the pre-filtering layer-anode 7.

[0022] Further, the pre-filtering layer-anode 7 is selected from one of a carbon-based material, a noble metal and a metal oxide, or a combination of the carbon-based material and the noble metal, or a combination of the carbon-based material and the metal oxide; the carbon-based material includes carbon paper, carbon felt, carbon rod, carbon fiber sheet, carbon brush, carbon foam, graphite plate, graphite rod, graphite sheet, graphite cloth, graphite particle, activated carbon and reticular glassy carbon; the noble metal includes Au and Pd; and the metal oxide includes MnO2, WO3 and TiO2.

[0023] Further, the ultrafiltration membrane 8 is a flat plate ultrafiltration membrane or a hollow fiber membrane.

[0024] An application of a low-pressure ultrafiltration wastewater treatment device based on bioelectrochemical enhancement is disclosed, which is used to treat the effluent from the secondary sedimentation tank of a wastewater treatment plant and the tailwater from livestock and poultry breeding. The treated water can be used for agricultural irrigation.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] This invention achieves the mineralization and removal of antibiotics, as well as the adsorption and retention of heavy metals, through a bio-filter cake layer on the pre-filtration layer-anode. By introducing bioelectrochemistry, the repulsion effect generated by the pre-filtration layer-anode reduces contaminant fouling of the membrane and increases flux. Electrons generated by the pre-filtration layer-anode can reduce heavy metal ions at the cathode via an external circuit, thereby passivating and detoxifying the heavy metals. The introduction of bioelectrochemistry also enhances antibiotic removal, reduces the heavy metal-antibiotic selective pressure, and decreases the abundance of ARGs, thus reducing their transmission risk. The ultrafiltration membrane of this invention can retain pathogens and ARBs. This method reduces the spread of ARGs; it achieves deep removal of pollutants, reduces the risk of resistance gene transmission, and enhances membrane fouling control. While retaining nitrogen and phosphorus resources, this method achieves deep removal of heavy metals and antibiotics, and inhibits the spread of resistance genes, enabling the safe reuse of nitrogen and phosphorus resources in wastewater effluent and livestock and poultry wastewater tailwater. In this method, low-pressure ultrafiltration utilizes the transmembrane pressure difference generated by gravitational potential energy to achieve continuous flow filtration, while coupled bioelectrochemistry utilizes the electrical energy generated by the biodegradation of organic matter to achieve heavy metal reduction and enhance the deep removal of antibiotics. The method has the advantages of being green, low-carbon, and sustainable. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the low-pressure ultrafiltration wastewater treatment device based on bioelectrochemical enhancement according to the present invention.

[0029] Figure 2 This is a schematic diagram showing the change in chemical oxygen demand (COD) concentration over time.

[0030] Figure 3 This is a schematic diagram showing the change in total nitrogen (TN) concentration over time.

[0031] Figure 4 This is a schematic diagram showing the change in total phosphorus (TP) concentration over time.

[0032] Figure 5 Figure 8 is a schematic diagram of copper (Cu) concentration change over time;

[0033] Figure 6 Figure 9 is a schematic diagram of tetracycline concentration change over time;

[0034] Figure 7 Figure 10 is a schematic diagram of relative abundance of tetracycline resistance genes (ARGs) at 30 and 60 days;

[0035] Figure 8 Figure 11 is a schematic diagram of flux change from 0 to 60 days.

[0036] In the figure, 1. Influent tank 2. Constant water level tank 3. Cathode 4. Resistance 5. Membrane module 6. Biological filter cake layer 7. Pre-filtering layer-anode 8. Ultrafiltration membrane 9. Water collecting device 10. Data acquisition module 11. Computer. DETAILED DESCRIPTION

[0037] The application will be described in further detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the application, and not to limit the application. In addition, it should be noted that, for the sake of description, only the parts related to the application are shown in the drawings, not all the structures.

[0038] It should be noted that: similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the application, the terms "first", "second" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0039] The application introduces a bioelectrochemical strategy into a low-pressure ultrafiltration system, and constructs a sewage treatment device integrated with a pre-filtering layer-anode. As shown in Figure 1 The application is based on a bioelectrochemically enhanced low-pressure ultrafiltration sewage treatment device, which is composed of an influent tank 1, a constant water level tank 2, a cathode 3, a resistance 4, a membrane module 5, a biological filter cake layer 6, a pre-filtering layer-anode 7, an ultrafiltration membrane 8, a water collecting device 9, a data acquisition module 10 and a computer 11.

[0040] Among them, the influent tank 1 is filled with collected sewage plant secondary sedimentation tank sewage and livestock and poultry breeding wastewater tail water, the bottom of the influent tank 1 is connected to the constant water level tank 2 through a pipeline provided with a stop valve, the constant water level tank 2 is provided with a float valve or other liquid level sensor, which can control the amount of water flowing into the constant water level tank 2 from the influent tank 1, so that the liquid level difference between the constant water level tank 2 and the ultrafiltration membrane 8 can be kept constant (0.2-1.0 bar).

[0041] The constant water level tank 2 is installed with a cathode 3, and the fixed position of the cathode 3 is just submerged by the liquid level in the constant water level tank 2; the cathode 3 is connected with the pre-filtering layer-anode 7 in the membrane module 5 through the connecting wire, so as to realize the coupling of the bioelectrochemistry and the low pressure ultrafiltration system.

[0042] The cathode 3 is made of carbon-based materials, including carbon paper (CP), carbon felt (CF), carbon rod (CR), carbon fiber sheet (CS), carbon brush (CB), carbon foam (CFO), graphite plate (GP), graphite rod (GR), graphite sheet (GS), graphite cloth (GC), graphite particles (GG), activated carbon (AC) and reticular glassy carbon (RGC).

[0043] The resistance 4 is 100-1000 ohm resistance.

[0044] The constant water level tank 2 is installed with a float ball valve and a water level sensor, so as to control the constant liquid level.

[0045] The bottom of the constant water level tank 2 is connected with the top of the membrane module 5 through the connecting pipeline, and the connecting pipeline is installed with a stop valve.

[0046] The pre-filtering layer-anode 7 is directly laid above the ultrafiltration membrane 8, and the biological filter cake layer 6 is arranged above the pre-filtering layer-anode 7. The biological filter cake layer 6 is composed of the initial inoculated biological, the filtered retained and proliferated biological, and the retained substances of the pre-filtering layer-anode 7.

[0047] The pre-filtering layer-anode 7 is selected from one of carbon-based materials, noble metals and metal oxides, or the combination of carbon-based materials and noble metals, or the combination of carbon-based materials and metal oxides. The carbon-based materials include carbon paper (CP), carbon felt (CF), carbon rod (CR), carbon fiber sheet (CS), carbon brush (CB), carbon foam (CFO), graphite plate (GP), graphite rod (GR), graphite sheet (GS), graphite cloth (GC), graphite particles (GG), activated carbon (AC) and reticular glassy carbon (RGC). The noble metals include Au and Pd. The metal oxides include MnO2, WO3 and TiO2.

[0048] The ultrafiltration membrane 8 is a flat plate ultrafiltration membrane or a hollow fiber membrane.

[0049] The membrane module 5 is provided with 0.2-1.0 bar operating pressure by water depth, and realizes the continuous flow filtration by the gravity potential energy corresponding to the water head. The side of the membrane module 5 is connected with the water collecting device 9 through the connecting pipeline, and the connecting pipeline is also installed with a stop valve.

[0050] The data acquisition module 10 is used to measure the voltage across the resistor 4, i.e. the voltage generated by the bioelectrochemical device. The computer 11 is used to collect the voltage data acquired by the data acquisition module 10, and to monitor the performance of the bioelectrochemical device in real time.

[0051] The present application is based on a low-pressure ultrafiltration sewage treatment method enhanced by bioelectrochemistry, which comprises the following steps:

[0052] A. The water in the water inlet tank 1 enters the constant water level tank 2;

[0053] B. The float valve and water level sensor of the constant water level tank 2 control the liquid level difference between the liquid surface of the constant water level tank 2 and the ultrafiltration membrane 8 to remain constant (0.2-1.0 bar);

[0054] C. The pre-filtering layer-anode 7 is inoculated and laid on the ultrafiltration membrane 8, and the biological filter cake layer 6 formed thereon removes organic matter and antibiotics through biological action; the biological filter cake layer 6, the pre-filtering layer-anode 7 and the ultrafiltration membrane 8 adsorb and retain heavy metals, pathogens and other substances;

[0055] D. The microorganisms in the biological filter cake layer 6 can produce electrons through the degradation of organic matter and antibiotics, which are transmitted to the cathode 3 through an external circuit, and the heavy metals are further removed through reduction at the cathode 3;

[0056] E. Due to the effective removal of heavy metals at the cathode 3 and the enhanced removal of antibiotics at the pre-filtering layer-anode 7, the accumulation of heavy metals and antibiotics in the biological filter cake layer 6 is reduced, thereby reducing the selective pressure of heavy metals-antibiotics and the risk of ARGs production and spread;

[0057] F. The water in the constant water level tank 2 flows out after passing through the biological filter cake layer 6, the pre-filtering layer-anode 7 and the ultrafiltration membrane 8, and is collected in the water collection device 9.

[0058] The present application is based on a low-pressure ultrafiltration sewage treatment device and method enhanced by bioelectrochemistry, which has the following advantages:

[0059] 1. The pre-filtering layer-anode is located at the deepest part of the water, and the biological filter cake layer formed thereon is in anoxic / anaerobic state. The microorganisms in the biological filter cake layer, especially the electroactive microorganisms, use organic matter and antibiotics as electron donors to achieve the mineralization and removal of antibiotics.

[0060] 2. The pre-filtering layer-anode formed by carbon-based materials, metal oxides or a combination of both can reduce the direct blockage of membrane pores by metal pollutants and reduce membrane fouling, thereby improving the flux. In addition, the electrostatic repulsion generated by the anode also reduces the pollution of the membrane by pollutants, thereby improving the flux.

[0061] 3. Cathode on the surface of water, in aerobic state, can reduce heavy metal ions by the electrons generated by anode, thus passivating heavy metals and losing toxicity, such as Cu 2+ reduced to Cu, Cd 2+ reduced to Cd, Se 4+ reduced to Se, Cr 6+ reduced to Cr 3+ .

[0062] 4. Due to the introduction of bioelectrochemistry, heavy metals are converted into other non-toxic valence states, and antibiotics are removed by strengthening, thus reducing the heavy metal-antibiotic selective pressure, reducing the abundance of ARBs and ARBs, and thus reducing their transmission risk.

[0063] 5. Ultrafiltration membrane can intercept pathogens such as fecal coliforms and roundworm eggs. It can also intercept ARBs and reduce the transmission of ARBs and ARGs.

[0064] 6. Due to the low removal efficiency of nitrogen and phosphorus in the whole system, the nitrogen and phosphorus resources are preserved. In addition, the above process realizes the deep removal of heavy metals and antibiotics, and inhibits the spread of resistance genes, so that the nitrogen and phosphorus resources in the effluent of sewage treatment plant and the tail water of livestock and poultry breeding wastewater can be safely reused.

[0065] 7. Bioelectrochemistry uses biological removal of organic matter and antibiotics to generate current to reduce heavy metals and strengthen antibiotic removal, and low-pressure ultrafiltration uses the transmembrane pressure difference generated by the gravity potential of water depth to realize continuous flow filtration, which significantly saves energy.

[0066] Example 1

[0067] A low-pressure ultrafiltration sewage treatment device based on bioelectrochemical strengthening, comprising a water inlet tank 1, a constant water level tank 2, a cathode 3, a resistor 4, a membrane assembly 5, a biological filter cake layer 6, a pre-filtering layer-anode 7, an ultrafiltration membrane 8, a water collecting device 9, a data acquisition module 10 and a computer 11.

[0068] Among them, the bottom of the water inlet tank 1 is connected to the constant water level tank 2 through a pipeline with a stop valve. The constant water level tank 2 is installed with a cathode 3, which is a carbon brush connected in series with a 1000-ohm resistor 4 and a pre-filtering layer-anode 7 in the membrane assembly 5 through a titanium wire. The constant water level tank 2 is provided with a floating ball valve, and the bottom of the constant water level tank 2 is connected to the top of the membrane assembly 5 through a connecting pipeline with a stop valve.

[0069] The pre-filtering layer-anode 7 is installed in the membrane module 5, laid above the ultrafiltration membrane 8, composed of carbon felt and Mn02. The pre-filtering layer-anode 7 forms a biological filter cake layer 6 above through inoculation and long-term filtration. The ultrafiltration membrane 8 adopts a flat plate ultrafiltration membrane (UP150). The membrane module 5 realizes a 0.007 mpa transmembrane pressure difference as the operating pressure by a 70 cm liquid level difference between the constant water level tank 2 and the ultrafiltration membrane 8. The whole device is a continuous flow filtration.

[0070] The side of the membrane module 5 is connected with the water collecting device 9 through a connecting pipeline provided with a stop valve. The data acquisition module 10 is used to measure the voltage of the resistor 4, that is, the voltage generated by the bioelectrochemistry of the device. The computer 11 is connected with the data acquisition module 10 and can receive the voltage data collected by the data acquisition module 10 and process it.

[0071] Example 2

[0072] A low-pressure ultrafiltration sewage treatment device based on bioelectrochemical enhancement is composed of a water inlet tank 1, a constant water level tank 2, a cathode 3, a resistor 4, a membrane module 5, a biological filter cake layer 6, a pre-filtering layer-anode 7, an ultrafiltration membrane 8, a water collecting device 9, a data acquisition module 10 and a computer 11.

[0073] The bottom of the water inlet tank 1 is connected with the constant water level tank 2 through a pipeline provided with a stop valve. The constant water level tank 2 is provided with the cathode 3, which is a carbon rod and is connected in series with the 100-ohm resistor 4 and the pre-filtering layer-anode 7 in the membrane module 5 through a titanium wire. The constant water level tank 2 is provided with a float ball valve, and the bottom of the constant water level tank 2 is connected with the top of the membrane module 5 through a connecting pipeline provided with a stop valve.

[0074] The pre-filtering layer-anode 7 is installed in the membrane module 5, laid above the ultrafiltration membrane 8, composed of carbon felt and AC. The pre-filtering layer-anode 7 forms a biological filter cake layer 6 above through inoculation and long-term filtration. The ultrafiltration membrane 8 adopts a flat plate ultrafiltration membrane (UP100). The membrane module 5 realizes a 0.01 mpa transmembrane pressure difference as the operating pressure by a 100 cm liquid level difference between the constant water level tank 2 and the ultrafiltration membrane. The whole device is a continuous flow filtration.

[0075] The side of the membrane module 5 is connected with the water collecting device 9 through a connecting pipeline provided with a stop valve. The data acquisition module 10 is used to measure the voltage of the resistor 4, that is, the voltage generated by the bioelectrochemistry of the device. The computer 11 is connected with the data acquisition module 10 and can receive the voltage data collected by the data acquisition module 10 and process it.

[0076] Example 3

[0077] A low-pressure ultrafiltration sewage treatment method based on bioelectrochemical enhancement comprises the following steps:

[0078] A. Water in the water inlet tank 1 enters the constant water level tank 2;

[0079] B. The liquid level difference between the liquid surface of the constant water level tank 2 and the ultrafiltration membrane 8 is maintained at 0.2-1.0 bar through the control of the float ball valve and the water level sensor;

[0080] C. The pre-filtering layer-anode 7 is inoculated and laid on the ultrafiltration membrane 8, and the biological filter cake layer 6 formed thereon removes organic matter and antibiotics through biological action; the biological filter cake layer 6, the pre-filtering layer-anode 7 and the ultrafiltration membrane 8 adsorb and retain heavy metals, pathogens and other substances;

[0081] D. Microorganisms in the biological filter cake layer 6 can produce electrons through the degradation of organic matter and antibiotics, which are transmitted to the cathode 3 through an external circuit, and heavy metals are further removed through reduction at the cathode 3;

[0082] E. Due to the effective removal of heavy metals at the cathode 3 and the enhanced removal of antibiotics at the pre-filtering layer-anode 7, the accumulation of heavy metals and antibiotics in the biological filter cake layer 6 is reduced, thereby reducing the heavy metal-antibiotic selective pressure, reducing the generation of ARGs and reducing the risk of ARGs transmission;

[0083] F. The water in the constant water level tank 2 flows out after passing through the biological filter cake layer 6, the pre-filtering layer-anode 7 and the ultrafiltration membrane 8, and is collected in the water collecting device 9.

[0084] Example 4

[0085] The effluent from the secondary sedimentation tank of a sewage treatment plant in Jilin was treated by the treatment device in Example 1, and the water quality was as follows: the COD value was 25-34 mg / L, the ammonia nitrogen concentration was 5.3-8.9 mg / L, the TN concentration was 17.6-23.5 mg / L, the TP concentration was 0.7-0.9 mg / L, the Cu 2+ concentration was 0.4-0.9 mg / L, and the tetracycline concentration was 89-106 ug / L.

[0086] The results showed that:

[0087] 1. >99.99% of pathogens were removed;

[0088] 2. The Cu 2+ concentration in the effluent was <0.1 mg / L;

[0089] 3. The tetracycline concentration in the effluent was below the detection limit;

[0090] 4. The effluent flux was stably maintained at 1.4-2.3 L / m 2 .h;

[0091] 5. The TN concentration in the effluent was reduced to 12.3-21.5 mg / L;

[0092] 6. The TP concentration in the effluent is reduced to 0.4-0.5 mg / L.

[0093] It can be seen that the treatment device of this embodiment can significantly reduce heavy metals, antibiotics and pathogens in water, while maintaining a high concentration of nitrogen and phosphorus resources, thus achieving safe and efficient resource utilization of wastewater.

[0094] Example 5

[0095] The wastewater from a pig farm in Jilin Province was treated using the treatment device described in Example 1. The water quality was as follows: COD 97.2-110.0 mg / L, ammonia nitrogen 19.5-21.5 mg / L, TN 36.2-38.7 mg / L, TP 3.0-3.3 mg / L, and Cu... 2+ The concentration is 1.4-1.6 mg / L, and the concentration of tetracycline is 388-435 ug / L.

[0096] turn out:

[0097] 1. Achieved >99.99% pathogen removal;

[0098] 2. Outflow Cu 2+ Concentration <0.3 mg / L;

[0099] 3. The tetracycline concentration in the effluent should be maintained between 3.4 and 16.5 ug / L;

[0100] 4. The outflow rate is stable at 4.31-6.2 L / m³. 2 .h;

[0101] 5. The TN concentration in the effluent decreased to 23.4-24.9 mg / L;

[0102] 6. The TP concentration in the effluent is reduced to 2.2-2.5 mg / L.

[0103] It can be seen that the treatment device of this embodiment can significantly reduce heavy metals, antibiotics and pathogens in water, while maintaining a high concentration of nitrogen and phosphorus resources, thus achieving safe and efficient resource utilization of wastewater.

[0104] like Figure 2 As shown, the COD concentration in the influent is around 100 mg / L, and the effluent concentration does not exceed 40 mg / L when the flow is stable.

[0105] like Figure 3 As shown, the total nitrogen concentration in the influent is around 37 mg / L, and the effluent concentration is no less than 23 mg / L when stable, indicating that the total nitrogen removal is relatively low and the nitrogen resources in the wastewater are well preserved.

[0106] like Figure 4As shown, the total phosphorus concentration in the influent is around 3 mg / L, and the effluent concentration is no less than 2.2 mg / L when stable, indicating that the total phosphorus removal is relatively low and the phosphorus resources in the wastewater are well preserved.

[0107] like Figure 5 As shown, when the influent copper concentration is around 1.5 mg / L, the effluent concentration is no higher than 0.3 mg / L when the concentration is stable, indicating that the heavy metal removal is relatively good.

[0108] like Figure 6 As shown, when the influent concentration of tetracycline is around 400 ug / L, the effluent concentration is no higher than 17 ug / L when the concentration is stable, indicating that the tetracycline removal is relatively good.

[0109] like Figure 7 As shown, the relative abundance of tetracycline resistance genes in raw water and treated water was measured on days 30 and 60, respectively. It can be seen that the relative abundance of tetracycline resistance genes in wastewater treated by bioelectrochemical low-pressure ultrafiltration was significantly reduced.

[0110] like Figure 8 As shown, the system flux stabilizes at 4.3-6.2 L / m³. 2 The .h file indicates that the system's throughput can reach a stable level and is relatively high during long-term operation.

[0111] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for treating sewage water by low pressure ultrafiltration based on bioelectrochemical reinforcement, characterized in that, The low-pressure ultrafiltration sewage treatment device is composed of a water inlet tank (1), a constant water level tank (2), a cathode (3), a resistor (4), a membrane assembly (5), a biological filter cake layer (6), a pre-filtering layer-anode (7), an ultrafiltration membrane (8), a water collecting device (9), a data acquisition module (10) and a computer (11). The water inlet tank (1) is internally provided with collected sewage from a secondary sedimentation tank of a sewage plant and livestock and poultry breeding wastewater tail water, and the bottom of the water inlet tank (1) is connected with the constant water level tank (2) through a pipeline provided with a stop valve; the constant water level tank (2) is internally provided with the cathode (3), and the cathode (3) is connected with the pre-filtering layer-anode (7) in the membrane assembly (5) through a connecting wire and a resistor (4); the bottom of the constant water level tank (2) is connected with the top of the membrane assembly (5) through a connecting pipeline, and a stop valve is arranged on the connecting pipeline; the pre-filtering layer-anode (7) is directly laid above the ultrafiltration membrane (8), and a biological filter cake layer (6) is arranged above the pre-filtering layer-anode (7). The treatment method comprises the following steps: A. The water in the water inlet tank (1) enters the constant water level tank (2); B. The liquid level difference between the liquid surface of the constant water level tank (2) and the ultrafiltration membrane (8) is kept at 0.2-1.0 bar through the float ball valve and the water level sensor of the constant water level tank (2); C. The pre-filtering layer-anode (7) is laid on the ultrafiltration membrane (8) after being inoculated, and the biological filter cake layer (6) formed thereon removes organic matter and antibiotics through biological action; the biological filter cake layer (6), the pre-filtering layer-anode (7) and the ultrafiltration membrane (8) adsorb and intercept heavy metals and pathogens; D. The microorganisms in the biological filter cake layer (6) can produce electrons through the degradation of organic matter and antibiotics, and the electrons are transmitted to the cathode (3) through an external circuit, and the heavy metals are further removed through reduction in the cathode (3); E. Since the heavy metals are effectively removed in the cathode (3) and the antibiotics are intensively removed in the pre-filtering layer-anode (7), the accumulation of heavy metals and antibiotics in the biological filter cake layer (6) is reduced, thereby reducing the heavy metal-antibiotic selective pressure and the generation and spread risk of ARGs; F. The water in the constant water level tank (2) flows out after passing through the biological filter cake layer (6), the pre-filtering layer-anode (7) and the ultrafiltration membrane (8), and is collected in the water collecting device (9).

2. A low pressure ultrafiltration sewage treatment device based on bioelectrochemical enhancement, characterized in that: The low-pressure ultrafiltration sewage treatment device is composed of a water inlet tank (1), a constant water level tank (2), a cathode (3), a resistor (4), a membrane assembly (5), a biological filter cake layer (6), a pre-filtering layer-anode (7), an ultrafiltration membrane (8), a water collecting device (9), a data acquisition module (10) and a computer (11). The water inlet tank (1) is internally provided with collected sewage of the secondary sedimentation tank of a sewage plant and livestock and poultry breeding wastewater tail water, and the bottom of the water inlet tank (1) is connected with a constant water level tank (2) through a pipeline provided with a stop valve; the constant water level tank (2) is internally provided with a cathode (3), the cathode (3) is connected with a pre-filtering layer-anode (7) in a membrane assembly (5) through a connecting wire through a resistor (4); the bottom of the constant water level tank (2) is connected with the top of the membrane assembly (5) through a connecting pipeline, and a stop valve is arranged on the connecting pipeline; the pre-filtering layer-anode (7) is directly laid above an ultrafiltration membrane (8), and a biological filter cake layer (6) is arranged above the pre-filtering layer-anode (7); The membrane assembly (5) is provided with an operating pressure of 0.2-1.0 bar by water depth, and a gravity potential corresponding to the water head is used to realize a transmembrane pressure difference, so as to realize continuous flow filtration; the side of the membrane assembly (5) is connected with a water collecting device (9) through a connecting pipeline, and a stop valve is also arranged on the connecting pipeline; the data acquisition module (10) is used for measuring the voltage between the two ends of the resistor (4); and the computer (11) is used for collecting the voltage data collected by the data acquisition module (10) and monitoring the bioelectrochemical performance in real time.

3. The low pressure ultrafiltration sewage treatment device based on bioelectrochemical enhancement according to claim 2, characterized in that: The constant water level tank (2) is provided with a float ball valve and a water level sensor, so that the water inflowing into the constant water level tank (2) from the water inlet tank (1) can be controlled, and the liquid level difference between the liquid surface of the constant water level tank (2) and the ultrafiltration membrane (8) can be kept constant.

4. The low pressure ultrafiltration sewage treatment device based on bioelectrochemical enhancement according to claim 2, characterized in that: The fixed position of the cathode (3) is just submerged by the liquid surface in the constant water level tank (2).

5. The low pressure ultrafiltration sewage treatment device based on bioelectrochemical enhancement according to claim 4, characterized in that: The cathode (3) is made of carbon-based materials, including carbon paper, carbon felt, carbon rod, carbon fiber sheet, carbon brush, carbon foam, graphite plate, graphite rod, graphite sheet, graphite cloth, graphite particles, activated carbon and reticular glass carbon.

6. The low pressure ultrafiltration sewage treatment device based on bioelectrochemical enhancement according to claim 2, characterized in that: The resistor (4) is a 100-1000 ohm resistor.

7. The low pressure ultrafiltration sewage treatment device based on bioelectrochemical enhancement according to claim 2, characterized in that: The biological filter cake layer (6) is composed of initial inoculated organisms, filtered and retained organisms and proliferated organisms, and substances retained by the pre-filtering layer-anode (7).

8. The low pressure ultrafiltration sewage treatment device based on bioelectrochemical enhancement according to claim 2, characterized in that: The pre-filtering layer-anode (7) is selected from one of carbon-based materials, noble metals and metal oxides, or a combination of carbon-based materials and noble metals, or a combination of carbon-based materials and metal oxides; the carbon-based materials include carbon paper, carbon felt, carbon rod, carbon fiber sheet, carbon brush, carbon foam, graphite plate, graphite rod, graphite sheet, graphite cloth, graphite particles, activated carbon and reticular glass carbon; the noble metals include Au and Pd; and the metal oxides include MnO2, WO3 and TiO2.

9. The low pressure ultrafiltration sewage treatment device based on bioelectrochemical enhancement according to claim 2, characterized in that: The ultrafiltration membrane (8) is a flat plate ultrafiltration membrane or a hollow fiber membrane.

10. The use of a low pressure ultrafiltration sewage treatment device based on bioelectrochemical reinforcement according to any one of claims 2-9, characterized in that: The device is used for treating sewage of the secondary sedimentation tank of a sewage plant and livestock and poultry breeding wastewater tail water, and the treated water can be used for agricultural irrigation.

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