Electrochemically enhanced low pressure ultrafiltration system and method for livestock and poultry breeding tail water reuse

Abstract

This invention belongs to the field of livestock and poultry breeding wastewater treatment and agricultural reuse technology, specifically relating to an electrochemically enhanced low-pressure ultrafiltration system and method for reusing livestock and poultry breeding wastewater. The electrochemically enhanced low-pressure ultrafiltration system includes an inlet tank, a constant-level water tank, a gravity-driven low-pressure ultrafiltration membrane module, a water collection device, and a constant-pressure driving power supply. The gravity-driven low-pressure ultrafiltration membrane module includes a reactor, and an anode, an ultrafiltration membrane, and a cathode pre-filtration layer installed within the reactor. The cathode pre-filtration layer consists of a biofilter cake layer and a cathode. This invention, an electrochemically enhanced low-pressure ultrafiltration system and method for reusing livestock and poultry breeding wastewater, addresses the characteristics of livestock and poultry breeding wastewater by employing an externally sourced constant voltage-driven electrochemically enhanced gravity-driven low-pressure ultrafiltration system. It can simultaneously achieve heavy metal reduction, antibiotic degradation, pathogen interception, inhibition of resistance gene transmission, and membrane fouling control under low-energy consumption conditions, while retaining nitrogen and phosphorus resources in the wastewater, ensuring safe reuse for agricultural irrigation.

Description

Technical Field

[0001] This invention belongs to the field of livestock and poultry breeding wastewater treatment and agricultural reuse technology, specifically relating to an electrochemically enhanced low-pressure ultrafiltration system and method for reusing livestock and poultry breeding tailwater. Background Technology

[0002] Even after initial treatment, livestock and poultry farm wastewater still contains high concentrations of organic matter (COD approximately 80-150 mg / L) and nitrogen and phosphorus nutrients. Re-irrigating farmland can significantly reduce the application of nitrogen and phosphorus fertilizers. However, the Cu in the wastewater... 2+ Zn 2+ The presence of heavy metals and pathogenic microorganisms such as E. coli and Ascaris eggs exceeding the limits of the "Agricultural Irrigation Water Quality Standard," along with high concentrations of tetracyclines, sulfonamides, and the proliferation of ARB-resistant bacteria, renders livestock and poultry wastewater unsafe for reuse. Direct reuse of this type of wastewater in farmland can easily lead to combined heavy metal and antibiotic pollution, inducing the spread of antibiotic resistance genes (ARGs) and threatening soil ecology and agricultural product safety.

[0003] Currently, bioelectrochemical systems (BES) coupled with gravity-driven low-pressure ultrafiltration (GDM) are being explored for advanced treatment of this type of wastewater. However, in practical operation, especially for typical livestock and poultry farm wastewater effluent with COD concentrations around 120 mg / L, the bioelectrochemical system exhibits the following significant drawbacks:

[0004] 1. Extremely low and unstable output voltage: Within this COD concentration range, and under conditions of higher concentrations of antibiotics and heavy metals, the system output voltage is only 20-50mV under an external resistance of 100-1000Ω, which is insufficient to drive the effective reduction and passivation of most heavy metal ions.

[0005] 2. Microbial activity is inhibited: Residual antibiotics and heavy metals in wastewater have biotoxicity to anodic electroactive microorganisms, resulting in slow system start-up, large fluctuations in current output, and unstable long-term operating performance.

[0006] 3. Limited pollutant removal efficiency: The effective reduction and passivation rate of heavy metal ions is poor under low voltage, which exacerbates selective pressure and leads to the proliferation and spread of ARBs and ARGs; in addition, antibiotic degradation under low voltage depends on microbial metabolism, which is inefficient and easily causes the accumulation of intermediate products such as nitrite.

[0007] 4. Insufficient membrane fouling control: Inadequate removal of heavy metals and antibiotics can lead to cumulative toxicity, inhibiting microbial activity, weakening the long-term flux stability of GDM, and limiting the system's flux performance.

[0008] In summary, existing bioelectrochemical coupled low-pressure ultrafiltration technology is insufficient to meet the actual needs of efficient, stable, rapid deep treatment and resource reuse of livestock and poultry breeding wastewater effluent. Summary of the Invention

[0009] The purpose of this invention is to provide an electrochemically enhanced low-pressure ultrafiltration system and method for the reuse of livestock and poultry breeding wastewater. By introducing an external constant voltage to replace the bioelectrochemical process that relies on microbial metabolism, the invention addresses the problems of existing treatment systems, such as extremely low and unstable output voltage, inhibited microbial activity, limited pollution removal efficiency, and insufficient membrane fouling control.

[0010] This invention is achieved through the following technical solution:

[0011] An electrochemically enhanced low-pressure ultrafiltration system for the reuse of livestock and poultry breeding wastewater mainly consists of an inlet tank 1, a constant water level tank 2, a gravity-driven low-pressure ultrafiltration membrane module 3, a water collection device 8, and a constant pressure driving power supply 9.

[0012] The gravity-driven low-pressure ultrafiltration membrane module 3 includes a reactor and an anode 4, an ultrafiltration membrane 7, and a cathode pre-filtration layer installed inside the reactor. The cathode pre-filtration layer consists of a bio-cake layer 5 and a cathode 6. The cathode 6 is laid on top of the ultrafiltration membrane 7 in close contact with it, and the bio-cake layer 5 is located above the cathode 6. The bio-cake layer 5 is composed of microorganisms initially inoculated, microorganisms filtered and retained by the cathode 6 and ultrafiltration membrane 7 during long-term operation, microorganisms that have proliferated, and retained substances.

[0013] The inlet tank 1 contains livestock and poultry breeding wastewater. The bottom of the inlet tank 1 is connected to the constant water level tank 2 via a pipeline. The constant water level tank 2 is equipped with a float valve and a water level sensor to control the amount of water flowing into the constant water level tank 2 from the inlet tank 1. The bottom of the constant water level tank 2 is connected to the top of the gravity-driven low-pressure ultrafiltration membrane module 3 reactor via a connecting pipeline. The outlet of the ultrafiltration membrane 7 at the bottom of the reactor is connected to the water collection device 8 via a connecting pipeline.

[0014] The anode 4 is connected to the positive terminal of the constant voltage drive power supply 9 via a connecting wire, and the negative terminal of the constant voltage drive power supply 9 is connected to the cathode 6 located below the anode 4 via a connecting wire.

[0015] Furthermore, shut-off valves are installed on the connecting pipes between the constant water level tank 2 and the gravity-driven low-pressure ultrafiltration membrane assembly 3, as well as on the connecting pipes between the reactor and the water collection device 8.

[0016] Furthermore, the distance between the cathode 6 and the anode 4 is 10-20cm, and the voltage of the constant voltage driving power supply 9 is 0.3-1.0V.

[0017] Furthermore, the constant water level tank 2 is equipped with a float valve and a water level sensor to control the amount of water flowing into the constant water level tank 2 from the inlet tank 1, so that the liquid level difference between the liquid level of the constant water level tank 2 and the ultrafiltration membrane 7 is maintained at 0.2-1.0 bar.

[0018] Furthermore, the anode 4 is made of carbon-based material or metal material. 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 particles, activated carbon, and reticulated glassy carbon. The metal material includes a metal electrode doped with transition metals or noble metals and N, P, and S elements. The transition metals are Ni and Fe. The noble metals are Au and Pd.

[0019] Furthermore, the cathode 6 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 reticulated glassy carbon.

[0020] Furthermore, the ultrafiltration membrane 7 includes a flat sheet ultrafiltration membrane and a hollow fiber membrane.

[0021] An application of an electrochemically enhanced low-pressure ultrafiltration system for the reuse of livestock and poultry breeding wastewater is disclosed. The system is used to treat livestock and poultry breeding wastewater, and the treated water can be used for agricultural irrigation.

[0022] An electrochemically enhanced low-pressure ultrafiltration method for reusing livestock and poultry farm wastewater includes the following steps:

[0023] A. Assembly of an electrochemically enhanced gravity-driven low-pressure ultrafiltration system:

[0024] A1. Connect the bottom of the inlet tank 1 to the constant water level tank 2, which is equipped with a float valve and a water level sensor, through a connecting pipe. The bottom of the constant water level tank 2 is connected to the top of the reactor through a connecting pipe.

[0025] A2. Microorganisms are inoculated onto cathode 6 to form a cathode pre-filtration layer. The cathode pre-filtration layer is then laid tightly onto ultrafiltration membrane 7 and installed in the reactor. The bio-filter cake layer 5 formed on cathode 6 can be filtered and retained by cathode 6 during the treatment process and continue to proliferate. Anode 4 is installed 10-20 cm above cathode 6 inside the reactor. The side of the reactor is connected to water collection device 8 through connecting pipes.

[0026] A3. Connect the anode 4 to the positive terminal of the constant voltage drive power supply 9 through a connecting wire, and connect the negative terminal of the constant voltage drive power supply 9 to the cathode 6 through a connecting wire.

[0027] B. Adjustment of the liquid level difference between the constant water level tank 2 and the ultrafiltration membrane 7:

[0028] Livestock and poultry breeding wastewater flows into the inlet tank 1. The wastewater then flows through the bottom pipe of the inlet tank 1 into the constant water level tank 2 located below it, and then through the bottom pipe of the constant water level tank 2 into the reactor. During the inflow process, the water volume is controlled by the shut-off valve on the connecting pipe between the inlet tank 1 and the constant water level tank 2 and the interception valve on the connecting pipe between the constant water level tank 2 and the reactor, based on the position information of the float valve in the constant water level tank 2 and the data of the water level sensor. This keeps the liquid level difference between the liquid surface of the constant water level tank 2 and the ultrafiltration membrane 7 at 0.2-1.0 bar. The gravitational potential energy generated by the 20-100 cm water head is used to generate a transmembrane pressure difference of 0.2-1.0 bar in the ultrafiltration membrane 7.

[0029] C. Coupling of electrochemistry and gravity-driven low-pressure ultrafiltration:

[0030] Under a constant voltage of 0.3-1.0V, organic matter and antibiotics in livestock and poultry breeding wastewater effluent can be degraded and removed by the biofilter cake layer 5, and can also be removed by the active oxygen generated on the anode 4 and microbial oxidation. Pathogens and resistant bacteria are intercepted and removed by the ultrafiltration membrane 7, and heavy metals can be removed by electrostatic adsorption and reduction passivation by the cathode 6. Through the coupling of electrochemical and gravity-driven low-pressure ultrafiltration, the effective removal of organic matter, antibiotics, heavy metals and pathogens in livestock and poultry breeding wastewater effluent is achieved, thereby reducing the selective pressure of heavy metals-antibiotics and reducing the generation and spread risk of ARGs.

[0031] D. Collection of treated livestock and poultry breeding wastewater effluent:

[0032] The treated livestock and poultry breeding wastewater flows out through the side connection pipe of the reactor and is collected in the water collection device 8.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. Stable and efficient voltage: It adopts a constant external voltage of 0.3-1.0V, which completely eliminates the problem of low voltage (20-50mV) caused by COD concentration and pollutant toxicity in bioelectrochemical systems, and ensures continuous and stable operation of the system.

[0035] 2. Rapid reduction of heavy metals: Constant voltage can drive Cu 2+ Cd 2+ Cr 6+ Heavy metals undergo electrochemical reduction on the cathode surface, enabling efficient removal of heavy metal ions on the first day of system startup;

[0036] 3. Highly efficient degradation of antibiotics: Electrochemical process generates ·OH, H2O2, and O2 in situ. -Under the influence of reactive oxygen species and more effective stimulation of microorganisms, it can rapidly degrade antibiotics such as tetracyclines and sulfonamides. Furthermore, no nitrite accumulates during operation.

[0037] 4. Significantly reduced membrane fouling: The cathode carbon felt has a negative charge on its surface, which effectively blocks negatively charged dissolved organic matter, humic acid and other pollutants in the water through electrostatic repulsion. The stable flux of the system is 50-120% higher than that of the bioelectrochemical system.

[0038] 5. Rapid start-up and stable operation: The system starts up quickly without relying on microbial enrichment and activation, and is unaffected by the combined toxicity of antibiotics and heavy metals.

[0039] 6. Comprehensive protection for safe reuse: The ultrafiltration membrane efficiently retains pathogens and resistant bacteria, effectively inhibits the spread of ARGs, and simultaneously achieves deep removal of pollutants and retention of nitrogen and phosphorus resources, so that the effluent meets the water quality requirements for agricultural irrigation. Attached Figure Description

[0040] 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.

[0041] Figure 1 This is a schematic diagram of the electrochemically enhanced low-pressure ultrafiltration system for the reuse of livestock and poultry breeding wastewater according to the present invention.

[0042] Figure 2 This is a schematic diagram showing the change of chemical oxygen demand (COD) concentration over time.

[0043] Figure 3 ammonia nitrogen NH4 + Schematic diagram of -N concentration change over time;

[0044] Figure 4 Nitrite nitrogen NO2 + Schematic diagram of -N concentration change over time;

[0045] Figure 5 Nitrate nitrogen NO3 + Schematic diagram of -N concentration change over time;

[0046] Figure 6 This is a schematic diagram showing the change of total phosphorus (TP) concentration over time.

[0047] Figure 7 This is a schematic diagram showing the change of copper (Cu) concentration over time.

[0048] Figure 8This is a schematic diagram showing the change in tetracycline (TC) concentration over time.

[0049] Figure 9 This is a schematic diagram of flux changes from 0 to 60 days.

[0050] Figure 10 A schematic diagram of the voltage at which the electrochemical low-pressure ultrafiltration system is stable and the voltage of the electrochemical gravity-driven low-pressure ultrafiltration system.

[0051] In the diagram, 1. Inlet tank; 2. Constant water level tank; 3. Gravity-driven low-pressure ultrafiltration membrane module; 4. Anode; 5. Biofilter cake layer; 6. Cathode; 7. Ultrafiltration membrane; 8. Water collection device; 9. Constant voltage drive power supply. Detailed Implementation

[0052] The present invention will be further described below with reference to embodiments:

[0053] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention and not the entire structure.

[0054] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0055] The existing bioelectrochemical coupled low-pressure ultrafiltration system faces the following technical bottlenecks when treating typical livestock and poultry farm wastewater:

[0056] (1) The system output voltage is low (20-50mV) and unstable, making it difficult to achieve efficient electrochemical reduction of heavy metals;

[0057] (2) The combined toxicity of antibiotics and heavy metals inhibits microbial activity, resulting in slow system startup and performance fluctuations;

[0058] (3) Antibiotics have a slow degradation rate and are accompanied by the problem of nitrite accumulation;

[0059] (4) Membrane fouling control relies on biological processes, and the cumulative toxic effects on the microbial community during long-term operation will significantly reduce flux. Therefore, this invention, targeting the characteristics of livestock and poultry breeding wastewater effluent, adopts an electrochemically enhanced gravity-driven low-pressure ultrafiltration system driven by an external constant voltage. This system is used to simultaneously achieve heavy metal reduction, antibiotic degradation, pathogen interception, inhibition of resistance gene transmission, and membrane fouling control under low energy consumption conditions, while retaining nitrogen and phosphorus resources in the wastewater to ensure safe reuse for agricultural irrigation.

[0060] like Figures 1-9 As shown, the electrochemically enhanced low-pressure ultrafiltration system for the reuse of livestock and poultry breeding wastewater of the present invention mainly consists of an inlet tank 1, a constant water level tank 2, a gravity-driven low-pressure ultrafiltration membrane module 3, a water collection device 8, and a constant pressure driving power supply 9.

[0061] The gravity-driven low-pressure ultrafiltration membrane module 3 includes a reactor, and an anode 4, an ultrafiltration membrane 7, and a cathode pre-filtration layer installed within the reactor. The gravity-driven low-pressure ultrafiltration membrane module 3 operates at a pressure of 0.2-1.0 bar provided by the water depth, using a water head of 20-100 cm. This means that the gravitational potential energy generated by the 20-100 cm water depth enables the ultrafiltration membrane 7 to generate a transmembrane pressure difference of 0.2-1.0 bar, thus achieving continuous flow filtration.

[0062] The cathode pre-filtration layer consists of a bio-filter cake layer 5 and a cathode 6. The cathode 6 is laid on top of the ultrafiltration membrane 7 in close contact with it, and the bio-filter cake layer 5 is provided above the cathode 6.

[0063] The inlet tank 1 contains wastewater from livestock and poultry farming, and the bottom of the inlet tank 1 is connected to a constant water level tank 2 via a pipe equipped with a shut-off valve.

[0064] The constant water level tank 2 is equipped with a float valve and a water level sensor to control the amount of water flowing into the constant water level tank 2 from the inlet tank 1, so that the liquid level difference between the liquid level in the constant water level tank 2 and the ultrafiltration membrane 7 remains constant.

[0065] The bottom of the constant water level tank 2 is connected to the top of the gravity-driven low-pressure ultrafiltration membrane module 3 reactor via a connecting pipe, and a shut-off valve is installed on the connecting pipe.

[0066] The outlet of the ultrafiltration membrane 7 at the bottom of the reactor is connected to the water collection device 8 via a connecting pipe, and a shut-off valve is also installed on the connecting pipe.

[0067] The anode 4 is connected to the positive terminal of the constant voltage driving power supply 9 via a connecting wire, and the negative terminal of the constant voltage driving power supply 9 is connected to the cathode 6 via a connecting wire. The cathode 6 is located below the anode 4, and the distance between the cathode and the anode is 10-20 cm. Specifically, the voltage of the constant voltage driving power supply 9 is 0.3-1.0V, the negative terminal is connected to the carbon-based material in the cathode pre-filtration layer, and the positive terminal is connected to the carbon-based material or metal material of the anode 4, realizing the coupling of electrochemical and gravity-driven low-pressure ultrafiltration.

[0068] Specifically, the anode 4 is made of carbon-based materials or metallic materials. 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 reticulated glassy carbon (RGC). The metallic materials include metal electrodes doped with transition metals or noble metals and elements such as N, P, and S; the transition metals are Ni, Fe, etc.; the noble metals are Au, Pd, etc.

[0069] The biofilter cake layer 5 is composed of microorganisms initially inoculated, microorganisms filtered and retained by the cathode 6 and ultrafiltration membrane 7 under long-term operation, microorganisms that have proliferated, and the retained substances.

[0070] The cathode 6 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 reticulated glassy carbon (RGC).

[0071] The ultrafiltration membrane 7 includes a flat sheet ultrafiltration membrane and a hollow fiber membrane.

[0072] This invention relates to the application of an electrochemically enhanced low-pressure ultrafiltration system for the reuse of livestock and poultry breeding wastewater. The treated water can be used for agricultural irrigation.

[0073] This invention relates to an electrochemically enhanced low-pressure ultrafiltration method for reusing livestock and poultry farming wastewater, comprising the following steps:

[0074] A. Assembly of an electrochemically enhanced gravity-driven low-pressure ultrafiltration system:

[0075] A1. Connect the bottom of the inlet tank 1 to the constant water level tank 2, which is equipped with a float valve and a water level sensor, through a connecting pipe. The bottom of the constant water level tank 2 is connected to the top of the reactor through a connecting pipe.

[0076] A2. Microorganisms are inoculated onto the cathode 6 to form a cathode pre-filtration layer, which is then laid tightly onto the ultrafiltration membrane 7 and installed in the reactor. The bio-filter cake layer 5 formed on the cathode 6 can be filtered and retained by the cathode 6 during the treatment process and continue to proliferate. The anode 4 is installed 10-20 cm above the cathode 6 inside the reactor. The water outlet of the ultrafiltration membrane 7 at the bottom of the reactor is connected to the water collection device 8 through a connecting pipe.

[0077] A3. Connect the anode 4 to the positive terminal of the constant voltage drive power supply 9 through a connecting wire, and connect the negative terminal of the constant voltage drive power supply 9 to the cathode 6 through a connecting wire.

[0078] B. Adjustment of the liquid level difference between the constant water level tank 2 and the ultrafiltration membrane 7:

[0079] Livestock and poultry breeding wastewater flows into the inlet tank 1. The wastewater then flows through the bottom pipe of the inlet tank 1 into the constant water level tank 2 located below it, and then through the bottom pipe of the constant water level tank 2 into the reactor. During the flow, the water volume is controlled by the shut-off valve on the connecting pipe between the inlet tank 1 and the constant water level tank 2, as well as the interception valve on the connecting pipe between the constant water level tank 2 and the reactor, based on the position information of the float valve in the constant water level tank 2 and the data from the water level sensor. This keeps the water level difference between the liquid level in the constant water level tank 2 and the ultrafiltration membrane 7 at 0.2-1.0 bar.

[0080] C. Coupling of electrochemistry and gravity-driven low-pressure ultrafiltration:

[0081] The gravitational potential energy generated by a water head of 20-100cm is used to achieve a transmembrane pressure difference of 0.2-1.0bar in the ultrafiltration membrane 7. At the same time, under a constant voltage of 0.3-1.0V, organic matter and antibiotics in livestock and poultry breeding wastewater can be degraded and removed by the biofilter cake layer 5, and can also be removed by the active oxygen generated on the anode 4 and microbial oxidation. Pathogens and resistant bacteria are intercepted and removed by the ultrafiltration membrane 7, and heavy metals can be removed by electrostatic adsorption and reduction passivation by the cathode 6. Through the coupling of electrochemical and gravity-driven low-pressure ultrafiltration, the effective removal of organic matter, antibiotics, heavy metals and pathogens in livestock and poultry breeding wastewater is achieved, thereby reducing the heavy metal-antibiotic selective pressure, reducing the generation of ARGs, and reducing the risk of ARGs transmission.

[0082] D. Collection of treated livestock and poultry breeding wastewater effluent:

[0083] The treated livestock and poultry breeding wastewater flows out through the side connection pipe of the reactor and is collected in the water collection device 8.

[0084] Example 1:

[0085] An electrochemically enhanced low-pressure ultrafiltration system for the reuse of livestock and poultry breeding wastewater comprises an inlet tank 1, a constant-level water tank 2, a gravity-driven low-pressure ultrafiltration membrane module 3, an anode 4, a biological filter cake layer 5, a cathode 6, an ultrafiltration membrane 7, a water collection device 8, and a constant-pressure drive power supply 9.

[0086] The gravity-driven low-pressure ultrafiltration membrane module 3 includes a reactor, and an anode 4, an ultrafiltration membrane 7, and a cathode pre-filtration layer installed within the reactor. The gravity-driven low-pressure ultrafiltration membrane module 3 operates at a pressure of 0.7 bar provided by the water depth, enabling continuous flow filtration. The gravitational potential energy generated by a 70 cm water head achieves a transmembrane pressure difference of 0.7 bar for the ultrafiltration membrane 7. The cathode pre-filtration layer consists of a biofilm layer 5 and a cathode 6. The cathode 6 is laid directly above the ultrafiltration membrane 7, with the biofilm layer 5 positioned above it. The biofilm layer 5 is composed of initially inoculated microorganisms, microorganisms retained and multiplied by the cathode 6 and ultrafiltration membrane 7 during long-term operation, and retained substances. The ultrafiltration membrane is a flat-sheet ultrafiltration membrane, UP150.

[0087] The inlet tank 1 contains wastewater from livestock and poultry farming. The bottom of the inlet tank 1 is connected to a constant-level water tank 2 via a pipeline. The constant-level water tank 2 is equipped with a float valve and a water level sensor to control the amount of water flowing into it from the inlet tank 1, maintaining a constant level difference between the liquid level in the constant-level water tank 2 and the ultrafiltration membrane 7. The bottom of the constant-level water tank 2 is connected to the top of the gravity-driven low-pressure ultrafiltration membrane module 3 reactor via a connecting pipeline. The outlet end of the ultrafiltration membrane 7 at the bottom of the reactor is connected to a water collection device 8 via a connecting pipeline. Shut-off valves are installed on the connecting pipelines between the constant-level water tank 2 and the gravity-driven low-pressure ultrafiltration membrane module 3, as well as on the connecting pipelines between the reactor and the water collection device 8.

[0088] The anode 4 is connected to the positive terminal of the constant voltage driving power supply 9 via a connecting wire, and the negative terminal of the constant voltage driving power supply 9 is connected to the cathode 6 located below the anode 4 via a connecting wire. The voltage of the constant voltage driving power supply 9 is 0.8V. The distance between the cathode 6 and the anode 4 is 20cm. The anode 4 is a carbon brush, and the cathode 6 is a carbon felt.

[0089] Example 2:

[0090] An electrochemically enhanced low-pressure ultrafiltration system for the reuse of livestock and poultry breeding wastewater comprises an inlet tank 1, a constant-level water tank 2, a gravity-driven low-pressure ultrafiltration membrane module 3, an anode 4, a biological filter cake layer 5, a cathode 6, an ultrafiltration membrane 7, a water collection device 8, and a constant-pressure drive power supply 9.

[0091] The gravity-driven low-pressure ultrafiltration membrane module 3 includes a reactor, and an anode 4, an ultrafiltration membrane 7, and a cathode pre-filtration layer installed within the reactor. The gravity-driven low-pressure ultrafiltration membrane module 3 operates at a pressure of 0.7 bar provided by the water depth, enabling continuous flow filtration. The gravitational potential energy generated by a 70 cm water head achieves a transmembrane pressure difference of 0.7 bar for the ultrafiltration membrane 7. The cathode pre-filtration layer consists of a biofilm layer 5 and a cathode 6. The cathode 6 is laid directly above the ultrafiltration membrane 7, with the biofilm layer 5 positioned above it. The biofilm layer 5 is composed of initially inoculated microorganisms, microorganisms retained and multiplied by the cathode 6 and ultrafiltration membrane 7 during long-term operation, and retained substances. The ultrafiltration membrane is a flat-sheet ultrafiltration membrane, UP150.

[0092] The inlet tank 1 contains wastewater from livestock and poultry farming. The bottom of the inlet tank 1 is connected to a constant-level water tank 2 via a pipeline. The constant-level water tank 2 is equipped with a float valve and a water level sensor to control the amount of water flowing into it from the inlet tank 1, maintaining a constant level difference between the liquid level in the constant-level water tank 2 and the ultrafiltration membrane 7. The bottom of the constant-level water tank 2 is connected to the top of the gravity-driven low-pressure ultrafiltration membrane module 3 reactor via a connecting pipeline. The outlet end of the ultrafiltration membrane 7 at the bottom of the reactor is connected to a water collection device 8 via a connecting pipeline. Shut-off valves are installed on the connecting pipelines between the constant-level water tank 2 and the gravity-driven low-pressure ultrafiltration membrane module 3, as well as on the connecting pipelines between the reactor and the water collection device 8.

[0093] The anode 4 is connected to the positive terminal of the constant voltage driving power supply 9 via a connecting wire, and the negative terminal of the constant voltage driving power supply 9 is connected to the cathode 6 located below the anode 4 via a connecting wire. The voltage of the constant voltage driving power supply 9 is 0.6V. The distance between the cathode 6 and the anode 4 is 15cm. The anode 4 is a carbon brush, and the cathode 6 is a carbon felt.

[0094] Example 3:

[0095] An electrochemically enhanced low-pressure ultrafiltration system for the reuse of livestock and poultry breeding wastewater comprises an inlet tank 1, a constant-level water tank 2, a gravity-driven low-pressure ultrafiltration membrane module 3, an anode 4, a biological filter cake layer 5, a cathode 6, an ultrafiltration membrane 7, a water collection device 8, and a constant-pressure drive power supply 9.

[0096] The gravity-driven low-pressure ultrafiltration membrane module 3 includes a reactor, and an anode 4, an ultrafiltration membrane 7, and a cathode pre-filtration layer installed within the reactor. The gravity-driven low-pressure ultrafiltration membrane module 3 operates at a pressure of 0.2 bar provided by the water depth, enabling continuous flow filtration. The gravitational potential energy generated by a 20 cm water head achieves a transmembrane pressure difference of 0.2 bar for the ultrafiltration membrane 7. The cathode pre-filtration layer consists of a biofilm layer 5 and a cathode 6. The cathode 6 is laid directly above the ultrafiltration membrane 7, with the biofilm layer 5 positioned above it. The biofilm layer 5 is composed of initially inoculated microorganisms, microorganisms retained and multiplied by the cathode 6 and ultrafiltration membrane 7 during long-term operation, and retained substances. The ultrafiltration membrane is a flat-sheet ultrafiltration membrane, UP150.

[0097] The inlet tank 1 contains wastewater from livestock and poultry farming. The bottom of the inlet tank 1 is connected to a constant-level water tank 2 via a pipeline. The constant-level water tank 2 is equipped with a float valve and a water level sensor to control the amount of water flowing into it from the inlet tank 1, maintaining a constant level difference between the liquid level in the constant-level water tank 2 and the ultrafiltration membrane 7. The bottom of the constant-level water tank 2 is connected to the top of the gravity-driven low-pressure ultrafiltration membrane module 3 reactor via a connecting pipeline. The outlet end of the ultrafiltration membrane 7 at the bottom of the reactor is connected to a water collection device 8 via a connecting pipeline. Shut-off valves are installed on the connecting pipelines between the constant-level water tank 2 and the gravity-driven low-pressure ultrafiltration membrane module 3, as well as on the connecting pipelines between the reactor and the water collection device 8.

[0098] The anode 4 is connected to the positive terminal of the constant voltage driving power supply 9 via a connecting wire, and the negative terminal of the constant voltage driving power supply 9 is connected to the cathode 6 located below the anode 4 via a connecting wire. The voltage of the constant voltage driving power supply 9 is 0.3V. The distance between the cathode 6 and the anode 4 is 10cm. The anode 4 is a carbon brush, and the cathode 6 is a carbon felt.

[0099] Example 4:

[0100] An electrochemically enhanced low-pressure ultrafiltration system for the reuse of livestock and poultry breeding wastewater comprises an inlet tank 1, a constant-level water tank 2, a gravity-driven low-pressure ultrafiltration membrane module 3, an anode 4, a biological filter cake layer 5, a cathode 6, an ultrafiltration membrane 7, a water collection device 8, and a constant-pressure drive power supply 9.

[0101] The gravity-driven low-pressure ultrafiltration membrane module 3 includes a reactor, and an anode 4, an ultrafiltration membrane 7, and a cathode pre-filtration layer installed within the reactor. The gravity-driven low-pressure ultrafiltration membrane module 3 operates at a pressure of 1.0 bar provided by the water depth, enabling continuous flow filtration. The gravitational potential energy generated by a 100 cm water head achieves a 1.0 bar transmembrane pressure difference in the ultrafiltration membrane 7. The cathode pre-filtration layer consists of a biofilm layer 5 and a cathode 6. The cathode 6 is laid directly above the ultrafiltration membrane 7, with the biofilm layer 5 positioned above it. The biofilm layer 5 is composed of initially inoculated microorganisms, microorganisms retained and multiplied by the cathode 6 and ultrafiltration membrane 7 during long-term operation, and retained substances. The ultrafiltration membrane is a flat-sheet ultrafiltration membrane, UP150.

[0102] The inlet tank 1 contains wastewater from livestock and poultry farming. The bottom of the inlet tank 1 is connected to a constant-level water tank 2 via a pipeline. The constant-level water tank 2 is equipped with a float valve and a water level sensor to control the amount of water flowing into it from the inlet tank 1, maintaining a constant level difference between the liquid level in the constant-level water tank 2 and the ultrafiltration membrane 7. The bottom of the constant-level water tank 2 is connected to the top of the gravity-driven low-pressure ultrafiltration membrane module 3 reactor via a connecting pipeline. The outlet end of the ultrafiltration membrane 7 at the bottom of the reactor is connected to a water collection device 8 via a connecting pipeline. Shut-off valves are installed on the connecting pipelines between the constant-level water tank 2 and the gravity-driven low-pressure ultrafiltration membrane module 3, as well as on the connecting pipelines between the reactor and the water collection device 8.

[0103] The anode 4 is connected to the positive terminal of the constant voltage driving power supply 9 via a connecting wire, and the negative terminal of the constant voltage driving power supply 9 is connected to the cathode 6 located below the anode 4 via a connecting wire. The voltage of the constant voltage driving power supply 9 is 1.0V. The distance between the cathode 6 and the anode 4 is 20cm. The anode 4 is a carbon brush, and the cathode 6 is a carbon felt.

[0104] Example 5:

[0105] An electrochemically enhanced low-pressure ultrafiltration method for reusing livestock and poultry farm wastewater includes the following steps:

[0106] A. Assembly of an electrochemically enhanced gravity-driven low-pressure ultrafiltration system:

[0107] A1. Connect the bottom of the inlet tank 1 to the constant water level tank 2, which is equipped with a float valve and a water level sensor, through a connecting pipe. The bottom of the constant water level tank 2 is connected to the top of the reactor through a connecting pipe.

[0108] A2. Microorganisms are inoculated onto the cathode 6 to form a cathode pre-filtration layer. The cathode pre-filtration layer is then laid tightly onto the ultrafiltration membrane 7 and installed in the reactor. The bio-filter cake layer 5 formed on the cathode 6 can be filtered and retained by the cathode 6 during the treatment process and continue to proliferate. The anode 4 is installed 20cm above the cathode 6 inside the reactor. The side of the reactor is connected to the water collection device 8 through connecting pipes.

[0109] A3. Connect the anode 4 to the positive terminal of the constant voltage drive power supply 9 through a connecting wire, and connect the negative terminal of the constant voltage drive power supply 9 to the cathode 6 through a connecting wire.

[0110] B. Adjustment of the liquid level difference between the constant water level tank 2 and the ultrafiltration membrane 7:

[0111] Livestock and poultry breeding wastewater flows into the inlet tank 1. The wastewater then flows through the bottom pipe of the inlet tank 1 into the constant water level tank 2 located below it, and then through the bottom pipe of the constant water level tank 2 into the reactor. During the inflow process, the water volume is controlled by the shut-off valve on the connecting pipe between the inlet tank 1 and the constant water level tank 2 and the interception valve on the connecting pipe between the constant water level tank 2 and the reactor, based on the position information of the float valve in the constant water level tank 2 and the water level sensor data. This keeps the liquid level difference between the liquid level in the constant water level tank 2 and the ultrafiltration membrane 7 at 0.7 bar. The gravitational potential energy generated by the 70 cm water head is used to generate a transmembrane pressure difference of 0.7 bar in the ultrafiltration membrane 7.

[0112] C. Coupling of electrochemistry and gravity-driven low-pressure ultrafiltration:

[0113] Under a constant voltage of 0.8V, organic matter and antibiotics in livestock and poultry breeding wastewater effluent can be degraded and removed by the biofilter cake layer 5, and can also be removed by the active oxygen generated on the anode 4 and microbial oxidation. Pathogens and resistant bacteria are intercepted and removed by the ultrafiltration membrane 7, and heavy metals can be removed by electrostatic adsorption and reduction passivation by the cathode 6. Through the coupling of electrochemical and gravity-driven low-pressure ultrafiltration, the effective removal of organic matter, antibiotics, heavy metals and pathogens in livestock and poultry breeding wastewater effluent is achieved, thereby reducing the selective pressure of heavy metals-antibiotics, reducing the generation of ARGs, and reducing the risk of ARGs transmission.

[0114] D. Collection of treated livestock and poultry breeding wastewater effluent:

[0115] The treated livestock and poultry breeding wastewater flows out through the side connection pipe of the reactor and is collected in the water collection device 8.

[0116] Example 6:

[0117] Both the existing bioelectrochemical low-pressure ultrafiltration system and the electrochemically enhanced low-pressure ultrafiltration system for livestock and poultry wastewater reuse described in Example 1 were used to treat wastewater from a pig farm in Jilin Province. The wastewater quality was as follows: COD 98-136 mg / L, ammonia nitrogen concentration 25.1-27.2 mg / L, nitrite nitrogen concentration 0 mg / L, nitrite nitrogen concentration 2.3-3.3 mg / L, TP concentration 4.5-4.9 mg / L, and Cu... 2+ The concentrations are 2.0-2.5 mg / L, and the tetracycline concentration is 475-510 ug / L. Both systems use flat-sheet ultrafiltration membranes (UP150), achieving a transmembrane pressure difference of 0.7 bar using gravitational potential energy generated by a 70 cm head. Both systems employ continuous flow filtration. The difference lies in the cathode and anode: the bioelectrochemical low-pressure ultrafiltration system uses a carbon brush and a carbon felt, with a 69 cm distance between them, and the external circuit is connected via a 1000 ohm resistor. In this embodiment, the electrochemical gravity-driven low-pressure ultrafiltration system uses a carbon brush as the anode and a carbon felt as the cathode, with a constant output voltage of 0.8 V and a 20 cm distance between the cathode and anode. Existing bioelectrochemical low-pressure ultrafiltration systems generate electricity through microorganisms, requiring an oxygen concentration gradient; that is, the cathode needs an aerobic state, and the anode needs an anaerobic state. Because it is a single-chamber system, a relatively high cathode-anode distance and anaerobic conditions generated by the bio-filter cake layer are required to achieve electricity generation. The constant voltage power supply used in this application does not require an oxygen concentration gradient, nor does it require a distance of 69cm between the cathode and anode. In this embodiment, a distance of 20cm is sufficient.

[0118] The bioelectrochemical low-pressure ultrafiltration system uses anodic microorganisms to oxidize organic matter and antibiotics, generating electrons to produce electrical energy, with the electrode in close contact with the ultrafiltration membrane serving as the anode. In contrast, the electrochemical gravity-driven low-pressure ultrafiltration system of this invention is directly connected to an external constant-voltage power supply 9, with the electrode in close contact with the ultrafiltration membrane 7 serving as the cathode 6. This invention employs a coupling method of electrochemical and gravity-driven low-pressure ultrafiltration. Organic matter and antibiotics can be removed by the active oxygen generated at the anode 4 and by microbial oxidation, and can also be degraded and removed by the biofilm layer 5 at the cathode 6. Heavy metals are electrostatically adsorbed by the cathode and removed by reduction passivation. Pathogens and resistant bacteria are retained and removed by the ultrafiltration membrane 7, preventing the spread of resistance genes. Furthermore, due to the deep removal of antibiotics and heavy metals, the generation of resistance genes and resistant bacteria is reduced. Simultaneously, since the cathode 6 is negatively charged, and the main organic pollutants and humic acids in livestock and poultry wastewater are also negatively charged, electrostatic repulsion alleviates membrane fouling, effectively achieving membrane fouling control.

[0119] turn out:

[0120] 1. Both the bioelectrochemical low-pressure ultrafiltration system and the electrochemical gravity-driven low-pressure ultrafiltration system achieved the removal of >99.99% of pathogens;

[0121] 2. Electrochemical gravity-driven low-pressure ultrafiltration system Cu 2+ The effluent concentration was reduced by 47.21% compared to the bioelectrochemical low-pressure ultrafiltration system;

[0122] 3. The tetracycline concentration in the effluent from the electrochemical gravity-driven low-pressure ultrafiltration system was reduced by 56.99% compared to the bioelectrochemical low-pressure ultrafiltration system;

[0123] 4. The effluent from the electrochemical gravity-driven low-pressure ultrafiltration system contains virtually no nitrite nitrogen, while the effluent from the bioelectrochemical low-pressure ultrafiltration system contains 1.34 mg / L of nitrite nitrogen.

[0124] 5. The TP effluent concentration of the electrochemical gravity-driven low-pressure ultrafiltration system was increased by 9.87% compared to the bioelectrochemical low-pressure ultrafiltration system;

[0125] 6. The stable flux of the electrochemical gravity-driven low-pressure ultrafiltration system is 93% higher than that of the bioelectrochemical low-pressure ultrafiltration system. It can be seen that by using a constant voltage, the heavy metals and antibiotics in livestock and poultry breeding wastewater can be significantly reduced, the stable flux can be increased, and a high concentration of nitrogen and phosphorus resources can be maintained, so as to realize the safe reuse of livestock and poultry breeding wastewater for agricultural irrigation.

[0126] like Figure 2 As shown, the stable COD effluent concentrations of the bioelectrochemical low-pressure ultrafiltration system and the electrochemical gravity-driven low-pressure ultrafiltration system were 46.53 mg / L and 30.54 mg / L, respectively, with the electrochemical gravity-driven low-pressure ultrafiltration system increasing the COD removal rate by 34.36%. Figure 3 As shown, the NH4+ levels in the bioelectrochemical low-pressure ultrafiltration system and the electrochemical gravity-driven low-pressure ultrafiltration system are stable. + The effluent concentrations of -N were 8.16 mg / L and 15.3 mg / L, respectively. The electrochemical gravity-driven low-pressure ultrafiltration system used NH4... + -N retention increased by 8.75%. For example... Figure 4 As shown, the NO2 content in the bioelectrochemical low-pressure ultrafiltration system and the electrochemical gravity-driven low-pressure ultrafiltration system is stable. - The NO2 concentrations in the effluent were 1.34 mg / L and 0.004 mg / L, respectively, indicating that the effluent from the electrochemical gravity-driven low-pressure ultrafiltration system contained virtually no NO2. - -N. For example... Figure 5 As shown, the NO3 content in the bioelectrochemical low-pressure ultrafiltration system and the electrochemical gravity-driven low-pressure ultrafiltration system is stable. - The NO3- concentrations in the effluent were 0.00 mg / L and 0.01 mg / L, respectively, indicating that the effluent from the electrochemical gravity-driven low-pressure ultrafiltration system contained virtually no NO3. - -N. For example... Figure 6As shown, the stable TP effluent concentrations of the bioelectrochemical low-pressure ultrafiltration system and the electrochemical gravity-driven low-pressure ultrafiltration system were 3.85 mg / L and 4.23 mg / L, respectively, with the electrochemical gravity-driven low-pressure ultrafiltration system showing a 9.87% increase in TP retention. Figure 7 As shown, the stable Cu effluent concentrations of the bioelectrochemical low-pressure ultrafiltration system and the electrochemical gravity-driven low-pressure ultrafiltration system were 0.725 mg / L and 0.383 mg / L, respectively, with the electrochemical gravity-driven low-pressure ultrafiltration system achieving a Cu removal rate of 95.3%. Figure 8 As shown, the tetracycline effluent concentrations at stable conditions in the bioelectrochemical low-pressure ultrafiltration system and the electrochemical gravity-driven low-pressure ultrafiltration system were 90.53 ug / L and 38.94 ug / L, respectively, with the electrochemical gravity-driven low-pressure ultrafiltration system achieving a Cu removal rate increase of 56.99%. Figure 9 As shown, the steady-state fluxes of the bioelectrochemical low-pressure ultrafiltration system and the electrochemical gravity-driven low-pressure ultrafiltration system were 1.434 LMH and 2.768 LMH, respectively, with the electrochemical gravity-driven low-pressure ultrafiltration system showing a 93% increase in steady-state flux. Figure 10 As shown, the voltage of the electrochemical low-pressure ultrafiltration system is 0.037mV when it is stable, while the voltage of the electrochemical gravity-driven low-pressure ultrafiltration system is always 0.8V.

[0127] Example 7:

[0128] The electrochemically enhanced low-pressure ultrafiltration system for livestock and poultry wastewater reuse described in Example 2 was used to treat wastewater from a pig farm in Jilin Province. The wastewater quality was as follows: COD 88-124 mg / L, ammonia nitrogen 18.1-24.5 mg / L, TN 55.4-64.23 mg / L, TP 3.57-5.62 mg / L, and Cu... 2+ The concentrations were 1.35-1.87 mg / L, and the tetracycline concentrations were 279-337 ug / L. The results showed that:

[0129] 1. Achieved >99.99% pathogen removal;

[0130] 2. Outflow Cu 2+ Concentration <0.22 mg / L;

[0131] 3. The tetracycline concentration in the effluent is between 25.4 and 47.3 ug / L;

[0132] 4. The outflow rate is stable at 2.1-2.6 L / m³. 2 .h;

[0133] 5. The TN concentration in the effluent is 37.23-45.64 mg / L;

[0134] 6. The TP concentration in the effluent is 2.9-4.5 mg / L.

[0135] It can be seen that using a constant voltage can significantly increase the levels of heavy metals and antibiotics in livestock and poultry breeding wastewater, improve stable flux, and maintain a high concentration of nitrogen and phosphorus resources, thus enabling the safe reuse of livestock and poultry breeding wastewater for agricultural irrigation.

[0136] 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. An electrochemically enhanced low-pressure ultrafiltration method for reusing livestock and poultry farm wastewater, characterized in that, Includes the following steps: A. Assembly of an electrochemically enhanced gravity-driven low-pressure ultrafiltration system: A1. Connect the bottom of the inlet tank (1) to the constant water level tank (2) equipped with a float valve and a water level sensor through a connecting pipe. The bottom of the constant water level tank (2) is connected to the top of the reactor through a connecting pipe. A2. Microorganisms are inoculated onto the cathode (6) to form a cathode pre-filtration layer. The cathode pre-filtration layer is then laid tightly onto the ultrafiltration membrane (7) and installed in the reactor. The bio-filter cake layer (5) formed on the cathode (6) can be filtered and retained by the cathode (6) during the treatment process and continue to proliferate. An anode (4) is installed 10-20 cm above the cathode (6) inside the reactor. The outlet of the ultrafiltration membrane (7) at the bottom of the reactor is connected to the water collection device (8) through a connecting pipe. A3. Connect the anode (4) to the positive terminal of the constant voltage drive power supply (9) through the connecting wire, and connect the negative terminal of the constant voltage drive power supply (9) to the cathode (6) through the connecting wire. B. Adjustment of the liquid level difference between the liquid level in the constant water level tank (2) and the ultrafiltration membrane (7): Livestock and poultry breeding wastewater flows into the inlet tank (1). The livestock and poultry breeding wastewater flows into the constant water level tank (2) located below it through the bottom pipe of the inlet tank (1), and then flows into the reactor through the bottom pipe of the constant water level tank (2). During the flow, the water volume is controlled by controlling the shut-off valve on the connecting pipe between the inlet tank (1) and the constant water level tank (2) and the interception valve on the connecting pipe between the constant water level tank (2) and the reactor, so that the liquid level difference between the liquid surface of the constant water level tank (2) and the ultrafiltration membrane (7) is maintained at 0.2-1.0 bar. The gravitational potential energy generated by the 20-100 cm water head is used to generate a transmembrane pressure difference of 0.2-1.0 bar in the ultrafiltration membrane (7). C. Coupling of electrochemistry and gravity-driven low-pressure ultrafiltration: Under a constant voltage of 0.3-1.0V, organic matter and antibiotics in livestock and poultry breeding wastewater can be degraded and removed by the biofilter cake layer (5), and can also be removed by active oxygen generated on the anode (4) and microbial oxidation. Pathogens and resistant bacteria are intercepted and removed by the ultrafiltration membrane (7), and heavy metals can be removed by electrostatic adsorption and reduction passivation of the cathode (6). Through the coupling of electrochemical and gravity-driven low-pressure ultrafiltration, the effective removal of organic matter, antibiotics, heavy metals and pathogens in livestock and poultry breeding wastewater is achieved, thereby reducing the selective pressure of heavy metals-antibiotics and reducing the generation and spread risk of ARGs. D. Collection of treated livestock and poultry breeding wastewater effluent: The treated livestock and poultry breeding wastewater flows out through the side connection pipe of the reactor and is collected in the water collection device (8); The system used for electrochemically enhanced low-pressure ultrafiltration for the reuse of livestock and poultry breeding wastewater mainly consists of an inlet tank (1), a constant water level tank (2), a gravity-driven low-pressure ultrafiltration membrane module (3), a water collection device (8), and a constant pressure driving power supply (9). The gravity-driven low-pressure ultrafiltration membrane module (3) includes a reactor and an anode (4), an ultrafiltration membrane (7), and a cathode pre-filtration layer installed in the reactor; the cathode pre-filtration layer consists of a bio-cake layer (5) and a cathode (6); the cathode (6) is laid on top of the ultrafiltration membrane (7) in close contact with it, and the bio-cake layer (5) is provided above the cathode (6); the bio-cake layer (5) is composed of microorganisms initially inoculated, microorganisms filtered and retained by the cathode (6) and ultrafiltration membrane (7) under long-term operation, and the retained substances; The inlet tank (1) contains livestock and poultry breeding wastewater tailwater. The bottom of the inlet tank (1) is connected to the constant water level tank (2) through a pipeline. The constant water level tank (2) is equipped with a float valve and a water level sensor to control the amount of water flowing into the constant water level tank (2) from the inlet tank (1). The bottom of the constant water level tank (2) is connected to the top of the gravity-driven low-pressure ultrafiltration membrane module (3) reactor through a connecting pipeline. The outlet end of the ultrafiltration membrane (7) at the bottom of the reactor is connected to the water collection device (8) through a connecting pipeline. The anode (4) is connected to the positive terminal of the constant voltage drive power supply (9) via a connecting wire, and the negative terminal of the constant voltage drive power supply (9) is connected to the cathode (6) located below the anode (4) via a connecting wire. The connecting pipes between the constant water level tank (2) and the gravity-driven low-pressure ultrafiltration membrane assembly (3), as well as the connecting pipes between the reactor and the water collection device (8), are equipped with shut-off valves; the distance between the cathode (6) and the anode (4) is 10-20cm, and the voltage of the constant pressure driving power supply (9) is 0.3-1.0V; the constant water level tank (2) is equipped with a float valve and a water level sensor to control the amount of water flowing into the constant water level tank (2) from the inlet tank (1), so that the liquid level difference between the liquid surface of the constant water level tank (2) and the ultrafiltration membrane (7) is maintained at 0.2-1.0bar; the anode (4) is made of carbon-based material or metal material, wherein The carbon-based materials include carbon paper, carbon felt, carbon rods, carbon fiber sheets, carbon brushes, carbon foam, graphite plates, graphite rods, graphite sheets, graphite cloth, graphite particles, activated carbon, and reticulated glassy carbon; the metal materials include metal electrodes doped with transition metals or noble metals and N, P, and S elements; the transition metals are Ni and Fe; the noble metals are Au and Pd; the cathode (6) uses carbon-based materials, wherein the carbon-based materials include carbon paper, carbon felt, carbon rods, carbon fiber sheets, carbon brushes, carbon foam, graphite plates, graphite rods, graphite sheets, graphite cloth, graphite particles, activated carbon, and reticulated glassy carbon; the ultrafiltration membrane (7) includes flat sheet ultrafiltration membranes and hollow fiber membranes; It is used to treat wastewater from livestock and poultry farming, and the treated water can be used for agricultural irrigation.

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