A kind of permeability good oxygen biological reaction wall based on piezoelectric effect strengthening

Abstract

The present application relates to a kind of based on piezoelectric effect reinforced permeability good oxygen biological reaction wall, piezoelectric material is filled as filler to be filled in permeable biological reaction wall body, the pulse hydraulic pressure produced by the flow field potential energy formed by groundwater extraction is used, the deformation of the surface of piezoelectric material occurs and generates electric charge and forms local electric potential field, stimulate microbial activity, to improve microbial colonization and pollutant degradation capacity.Permeable biological reaction wall is provided with the baffle of hollow fiber membrane assembly, and through super micro bubble aeration, the in-situ aerobic metabolic efficiency of microorganism is increased, the release of volatile and semi-volatile organic pollutants in groundwater is avoided to escape and scatter and influence surrounding environment.The present application realizes long-term efficient groundwater composite organic pollutants green low-carbon sustainable biological process control, significantly improves groundwater composite organic pollution repair efficiency, avoids secondary pollution and repair tailing rebound phenomenon, and realizes long-term groundwater pollution risk management and control.

Description

Technical Field

[0001] This invention relates to the field of groundwater pollution remediation technology, and in particular to a permeable aerobic bioreactor wall using piezoelectric materials and arrayed hollow fiber membranes. Background Technology

[0002] Groundwater extraction and treatment technology, through the establishment of a well network system, can rapidly reduce the degree of groundwater pollution by extracting and treating contaminated groundwater. This approach can effectively control the flow of contaminated groundwater. While the extracted contaminated groundwater can quickly reduce pollutant concentrations through physicochemical methods, the non-uniformity of groundwater flow velocity, direction, and permeability coefficients leads to tailing and rebound phenomena at the treated site. This makes complete remediation of the contaminated site difficult, resulting in low efficiency and high costs in the long run.

[0003] Microbial remediation is a green and sustainable method that utilizes the natural metabolic processes of microorganisms to degrade or transform pollutants without generating secondary pollution and with minimal environmental disturbance. Microorganisms under aerobic conditions have a rapid metabolic rate, enabling them to degrade organic matter more quickly and shorten remediation time. Aerobic microorganisms can completely mineralize organic pollutants into harmless carbon dioxide and water, providing more thorough pollutant removal. Although aerobic remediation requires aeration, its energy consumption is generally lower than that of anaerobic remediation, and it does not produce the odor and potential air pollution problems associated with anaerobic organisms. Groundwater with complex organic pollution is often accompanied by heavy metal pollution, and the presence of heavy metal ions further affects microbial growth and pollutant degradation. Anoxic groundwater environments inhibit the growth and metabolism of aerobic bacteria that degrade complex organic pollutants. Aeration devices using hollow fiber membranes as core components can provide remediation gases in the form of microbubbles while preventing the escape of volatile organic compounds. Traditional bundled devices are prone to biofilm formation, leading to clogging and difficult cleaning, making them unsuitable for long-term operation.

[0004] A permeable reactive barrier (PRB) is a method for in-situ groundwater remediation. It involves installing a wall filled with a specific reactive medium along the path of contaminated groundwater. As the groundwater passes through the wall, contaminants react physicochemically with the reactive medium, resulting in their removal or transformation into environmentally acceptable forms. However, PRB technology is not suitable for sites with complex contamination types because the target contaminant removal is determined by the reactive medium it contains. Furthermore, over time, the effectiveness of the PRB system may decrease due to contaminant accumulation and sediment buildup, potentially requiring periodic replacement or regeneration of the reactive medium, increasing maintenance costs and complexity.

[0005] Therefore, developing a permeable reactive barrier for the continuous and deep purification of groundwater with low concentrations of complex organic pollution is a technical solution that urgently needs to be solved. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a piezoelectric permeable reactive aerobic biobarrier (PPRABB) enhanced by the piezoelectric effect.

[0007] To achieve the above objectives, the present invention provides the following solution: a permeable aerobic bioreactor wall enhanced by the piezoelectric effect, wherein the bioreactor wall comprises piezoelectric material modules, arrayed hollow fiber modules, an extraction pump, an air pump, a rotor flow meter, a hydraulic-electric control valve, and a water flow velocity meter, wherein the piezoelectric material modules and arrayed hollow fiber membrane modules are arranged alternately to form the main body of the permeable bioreactor wall, and the piezoelectric material modules are close to the soil at both ends.

[0008] The air pump is connected to the air inlet of the hollow fiber membrane module through a gas transport pipeline. The rotor flow meter is installed on the gas transport pipeline. The gas is evenly transported to each hollow fiber membrane filament through the gas pipelines arranged on the hollow fiber membrane module frame. At the same time, the hollow fiber membrane module frame plays a role in fixing and arranging the hollow fiber membrane filaments.

[0009] The extraction pump is located upstream of the reaction wall and connected to the groundwater source via pipeline. The pump draws water through the pipeline without directly contacting the groundwater, ensuring effective extraction and delivery. A hydraulic-electric control valve is installed on the pump's outlet pipeline, immediately following the pump. This valve regulates the water pressure and flow rate, ensuring the system can dynamically adjust the extraction efficiency as needed. A flow velocity meter is installed in the pipeline downstream of the control valve, at a distance to avoid interference. The flow velocity meter monitors the water flow rate through the pipeline in real time, providing necessary data to optimize system operation.

[0010] Preferably, the piezoelectric material and the stainless steel perforated plate form a piezoelectric material module. The stainless steel perforated plate provides support and positioning to both sides of the piezoelectric material, preventing displacement and inaccurate force application. The perforated plate is made of stainless steel, and its internal pores allow water to flow out with almost no resistance. The pore size and density can be adjusted according to actual needs.

[0011] The piezoelectric material is a composite piezoelectric material, composed of lead-free ceramic microparticles (potassium sodium niobate KNN and barium titanate BT) and a piezoelectric polymer (polyvinylidene fluoride PVDF).

[0012] The composite piezoelectric material is prepared by adding KNN and BT microparticles to PVDF slurry using an additive manufacturing process of "layer-by-layer manufacturing." The mass ratio of KNN, BT, and PVDF is 0.1-0.5:0.1-0.5:1-3. This piezoelectric material is permeable to water while preventing soil particles from entering the permeable aerobic bioreactor wall. It utilizes the hydraulic pressure generated during groundwater migration to create a non-uniform electric field, reducing heavy metal ions in groundwater contaminated with complex organic pollutants. Simultaneously, it can stimulate microbial degradation activity under low-temperature conditions. The piezoelectric material can be replaced with one that has better biocompatibility, stronger electrostatic performance, better stability, and higher permeability. The piezoelectric material exhibits anti-fouling and anti-clogging potential against organic matter, oils, and proteins, improving its durability.

[0013] Preferably, the array hollow fiber membrane module is composed of multiple hollow fiber membranes arranged closely in an array, with each array of hollow fiber membranes having a uniform thickness and positioned using slots. This allows the wall to withstand pulsed hydraulic pressure without displacement, preventing groundwater from failing to fully permeate the permeable bioreactor wall due to hydraulic displacement. The hollow fiber membrane module provides dissolved oxygen in the form of microbubbles while preventing the escape of volatile organic compounds. The gas transport pipeline can be used not only to provide gas but also to transport liquid supplies, such as pH adjusting solutions, exogenous functional microorganisms, and liquid nutrients.

[0014] Preferably, the bottom and sides of the permeable bioreactor wall are pre-set with slots for positioning the piezoelectric material and the hollow fiber membrane in the array.

[0015] Hollow fiber membrane filaments arranged horizontally are tightly bonded and fixed on an array of hollow fiber membrane frames to form an array of hollow fiber membranes. Several arrays of hollow fiber membranes form a hollow fiber membrane module, which is bonded to a piezoelectric material module to form a unit. PM-PRBB is composed of several of the above units.

[0016] The hollow fiber membrane has a spacing of 0.1-0.3 cm between filaments, a pore size of 0.05-0.1 μm, an inner diameter of 0.5-1 mm, an outer diameter of 1-2 mm, a filament length of 0.5-5 m, and an aeration rate of 0.1-0.5 L / m³. 2 ·min.

[0017] Preferably, the bottom of the permeable bioreactor wall should be connected to the upper layer of the first weakly permeable layer. At the same time, cement is sprayed and cut into the soil at a certain pressure through high-pressure jet grouting on both sides of the bioreactor wall, and mixed with the soil to form a cylindrical pile, thereby forming a water-stop curtain, so that the polluted groundwater can flow completely through the permeable bioreactor wall based on piezoelectric materials.

[0018] Preferably, the extraction pump pressure is within the range of 1-10 MPa. The groundwater extraction flow rate is controlled by adjusting the pressure, with a high flow rate of 5-10 m / s and a low flow rate of 0.1-0.5 m / s. The extraction pump draws groundwater from a specified depth of soil, and a periodically controlled valve regulates the extraction flow rate, thereby transmitting pulsed hydraulic pressure to the piezoelectric material. A pre-embedded gas transport pipeline connects to the air inlet of the array of hollow fiber membrane modules, and the connection is wrapped with polyurethane material to improve airtightness and durability. The piezoelectric material modules and the array of hollow fiber membrane modules are arranged alternately to form the main structure of the permeable bioreactor wall, with the piezoelectric material modules close to the soil at both ends. The number and order of the middle section of the permeable bioreactor wall can be adjusted according to the site's hydrogeological conditions, site size, and pollutant removal effect.

[0019] Preferably, the surface of the hollow fiber membrane in the array is configured with a sinusoidal corrugated structure.

[0020] The PPRAB provided by this invention includes an extraction system that controls the flow of contaminated groundwater. The pulsed hydraulic pressure generated by the potential energy of the flow field formed by extracting contaminated groundwater causes deformation of the piezoelectric material surface, thereby generating an electric charge and forming a local electrochemical region.

[0021] Furthermore, an electric field can induce electromigration of charged molecules (including electron donors / acceptors, soluble pollutants, and nutrients), thereby inducing pore water flow through electroosmosis and improving its bioavailability in underground aquifers.

[0022] Furthermore, electrochemical reduction can be applied to most heavy metals, such as copper, chromium, cadmium, mercury, uranium, and vanadium. Electroactive bacteria (such as Geobacter) are widely present in groundwater environments and can effectively catalyze metal reduction. This approach avoids the degradation of metal-stressed organic pollutants in groundwater by active microorganisms.

[0023] Furthermore, under low-temperature underground conditions, electrochemical action can stimulate the activity of microorganisms and enhance their ability to metabolize complex organic pollutants.

[0024] Furthermore, the electric field attracts some electroactive microorganisms to migrate, alleviating the pore blockage caused by excessive microbial growth on the hollow fiber membrane in the array.

[0025] Furthermore, piezoelectric materials have the potential to resist pollution and clogging by organic matter, oils, and proteins, thus improving their durability.

[0026] Specifically, the piezoelectric material is a composite piezoelectric material, composed of lead-free ceramic microparticles (potassium sodium niobate KNN and barium titanate BT) and a piezoelectric polymer (polyvinylidene fluoride PVDF).

[0027] Preferably, the composite piezoelectric material is prepared by adding KNN and BT microparticles to PVDF slurry and using an additive manufacturing process of "layer-by-layer manufacturing".

[0028] Specifically, a perforated plate provides support and positioning to the piezoelectric material on both sides, forming a piezoelectric material module and preventing the material from shifting or failing to accurately bear force. The perforated plate is made of stainless steel, and its internal pores allow water to flow out with almost no resistance. The size and density of the pores can be adjusted according to actual needs.

[0029] Furthermore, ultra-microbubble aeration is achieved through an array of hollow fiber membranes. The dense sinusoidal corrugated structure on the surface of the array of hollow fiber membranes is not prone to clogging, has strong anti-fouling ability, and improves the water body shock load of the device while enhancing the system stability.

[0030] Furthermore, the hollow fiber membrane in the array is connected to an air pump to obtain external oxygen. The ultra-high surface energy of the ultrafine bubbles (diameter less than 2μm) allows them to bind tightly with water molecules, enabling the bubbles to settle and dissipate in the water. The microporous structure of the hollow fiber membrane, coupled with a gas control workstation, allows the blown-in air to enter the groundwater in the form of ultrafine bubbles, increasing dissolved oxygen in the water while preventing the escape of volatile organic compounds from the groundwater.

[0031] Furthermore, by providing oxygen needed for aerobic functional microorganisms to degrade complex organic pollutants through aeration, the indigenous functional bacteria are activated, and an effective functional microbial community is established.

[0032] Furthermore, PPRABs are adaptable to different hydrogeological conditions and pollutant characteristics, exhibiting a degree of flexibility. Some microorganisms can degrade recalcitrant organic pollutants that are difficult to treat using physicochemical methods. Microbial remediation not only removes pollutants but also promotes the health and stability of soil and groundwater ecosystems, contributing to the restoration and maintenance of ecological balance.

[0033] Specifically, an array of hollow fiber membranes is formed by tightly bonded, horizontally arranged hollow fiber membrane filaments. Several arrays of hollow fiber membranes form a hollow fiber membrane module, which is bonded to a piezoelectric material module to form a unit. PM-PRBB is composed of several of the above units.

[0034] Preferably, the spacing between the hollow fiber membrane filaments is 0.1-0.3 cm, the pore size of the filaments is 0.05-0.1 μm, the inner diameter of the filaments is 0.5-1 mm, the outer diameter of the filaments is 1-2 mm, the filament length is 0.5-5 m, and the aeration rate is 0.1-0.5 L / m. 2 ·min.

[0035] Meanwhile, this invention also provides a method for controlling permeable bioreactor wall technology based on piezoelectric materials, comprising the following steps:

[0036] (1) Based on the target pollution plume of the site, the PPRAB is placed downstream of the groundwater flow direction, and the wall height range covers the pollution plume area. The wall width is determined to be 2-5 m based on the size of the site.

[0037] (2) The depth of the PPRAB should reach the silty clay layer or the first weak permeable layer. The surrounding area is equipped with vertical barriers of the same width to guide polluted groundwater through the wall. High-pressure jet grouting is used to spray cement at a certain pressure to cut the soil and mix it with the soil to form a cylindrical pile body, thus forming a water-stopping curtain.

[0038] (3) Construct a groundwater extraction system to extract groundwater behind the PPRAB along the direction of groundwater flow, including water distribution observation ports, extraction diversion pipes, pebble layers, extraction wells, etc. Equip with a monitoring and control system, including hydraulic electric control valves, water flow velocity meters, etc. During the extraction process, the hydraulic electric control valves and water flow velocity meters generate periodic pulse water pressure.

[0039] The beneficial effects of this invention are:

[0040] 1. Without an external power source, the permeable bioreactor wall based on piezoelectric materials utilizes the pulsed hydraulic pressure generated by the potential energy of the flow field formed by groundwater extraction to deform the surface of the piezoelectric material, generate charges, and form a local electric potential field. This alleviates the wall blockage phenomenon, improves the wall's durability, reduces the inhibitory effect of heavy metal ions on microbial activity, increases the bioavailability of electron donors / acceptors, nutrients, and pollutants, and promotes microbial degradation activity through electrical stimulation.

[0041] 2. The hollow fiber membrane in the array is aerated in the form of microbubbles, which provides oxygen required by aerobic microorganisms while avoiding the escape of volatile or semi-volatile organic compounds. During operation, the membrane surface exhibits a sinusoidal corrugated structure, which can alleviate pore blockage. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the permeable bioreactor wall structure based on piezoelectric materials and its application in the field, according to the present invention.

[0043] Figure 2 This is a three-dimensional view of the array hollow fiber membrane of the present invention;

[0044] Figure 3 This is a schematic diagram of the stainless steel perforated plate of the present invention.

[0045] In the figure: 1. Piezoelectric material; 2. Arrayed hollow fiber membrane; 3. Stainless steel perforated plate; 4. Extraction pump; 5. Air pump; 6. Rotor flow meter; 7. Hydraulic-electric control valve; 8. Water flow rate meter; 9. Slot; 10. Hollow fiber membrane filaments; 11. Arrayed hollow fiber membrane frame; 12. Air inlet of arrayed hollow fiber membrane frame. Detailed Implementation

[0046] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0047] Example 1: See Figures 1-3 A permeable aerobic bioreactor based on piezoelectric effect enhancement is disclosed. The bioreactor comprises piezoelectric material modules, arrayed hollow fiber modules, an extraction pump 4, an air pump 5, a rotor flowmeter 6, a hydraulic-electric control valve 7, and a water flow rate gauge 8. The piezoelectric material modules and arrayed hollow fiber membrane modules are arranged alternately to form the main body of the permeable bioreactor. The piezoelectric material modules are close to the soil at both ends. The air pump 5 is connected to the air inlet of the hollow fiber membrane module via a gas transport pipe. The rotor flowmeter 6 is installed on the gas transport pipe, and gas is evenly transported to each hollow fiber membrane filament through gas channels laid out on the hollow fiber membrane module frame. Simultaneously, the hollow fiber membrane module frame fixes and arranges the hollow fiber membrane filaments. The extraction pump 4 is located upstream of the entire bioreactor and is connected to a groundwater source via a pipe. The extraction pump 4 draws water through the pipe without directly contacting the groundwater, ensuring effective water extraction and delivery. The hydraulic-electric control valve 7 is installed on the outlet pipe of the extraction pump, immediately following the extraction pump. The hydraulic-electric control valve 7 is used to regulate the pressure and flow rate of the water, ensuring that the system can dynamically adjust the extraction effect according to demand. The water velocity gauge 8 is installed in the pipeline section downstream of the hydraulic-electric control valve, at a certain distance from the control valve to avoid interference. The water velocity gauge 8 monitors the water flow rate through the pipeline in real time, providing necessary data to optimize system operation.

[0048] Preferably, the piezoelectric material 1 and the stainless steel perforated plate 3 form a piezoelectric material module. The stainless steel perforated plate 3 provides support and positioning to both sides of the piezoelectric material, preventing displacement of the piezoelectric material and ensuring accurate force application. The perforated plate is made of stainless steel, and its internal pores allow water to flow out with almost no resistance. The size and density of the pores can be adjusted according to actual needs.

[0049] The piezoelectric material 1 is a composite piezoelectric material, composed of lead-free ceramic microparticles (potassium sodium niobate KNN and barium titanate BT) and a piezoelectric polymer (polyvinylidene fluoride PVDF).

[0050] The composite piezoelectric material is prepared by adding KNN and BT microparticles to PVDF slurry using an additive manufacturing process of "layer-by-layer manufacturing." The mass ratio of KNN, BT, and PVDF is 0.1-0.5:0.1-0.5:1-3. This piezoelectric material is permeable to water while preventing soil particles from entering the permeable aerobic bioreactor wall. It utilizes the hydraulic pressure generated during groundwater migration to create a non-uniform electric field, reducing heavy metal ions in groundwater contaminated with complex organic pollutants. Simultaneously, it can stimulate microbial degradation activity under low-temperature conditions. The piezoelectric material can be replaced with one that has better biocompatibility, stronger electrostatic performance, better stability, and higher permeability. The piezoelectric material exhibits anti-fouling and anti-clogging potential against organic matter, oils, and proteins, improving its durability.

[0051] Preferably, the array hollow fiber membrane module is composed of multiple hollow fiber membranes arranged closely in an array, with each array of hollow fiber membranes having a uniform thickness and positioned using slots. This allows the wall to withstand pulsed hydraulic pressure without displacement, preventing groundwater from failing to fully permeate the permeable bioreactor wall due to hydraulic displacement. The hollow fiber membrane module provides dissolved oxygen in the form of microbubbles while preventing the escape of volatile organic compounds. The gas transport pipeline can be used not only to provide gas but also to transport liquid supplies, such as pH adjusting solutions, exogenous functional microorganisms, and liquid nutrients.

[0052] The bottom and sides of the permeable bioreactor wall are pre-set with slots 9 for positioning the piezoelectric material and the hollow fiber membrane in the array.

[0053] Hollow fiber membrane filaments 10 arranged horizontally are tightly bonded and fixed on an array of hollow fiber membrane frames 11 to form an array of hollow fiber membranes 2. Several arrays of hollow fiber membranes 2 form a hollow fiber membrane module, which is bonded to a piezoelectric material module to form a unit. PM-PRBB is composed of several of the above units.

[0054] The hollow fiber membrane has a spacing of 0.1-0.3 cm between filaments, a pore size of 0.05-0.1 μm, an inner diameter of 0.5-1 mm, an outer diameter of 1-2 mm, a filament length of 0.5-5 m, and an aeration rate of 0.1-0.5 L / m³. 2 ·min.

[0055] The bottom of the permeable bioreactor wall should be connected to the upper layer of the first weakly permeable layer. At the same time, cement is sprayed and cut into the soil at a certain pressure through high-pressure jet grouting on both sides of the bioreactor wall. The cement is mixed with the soil to form a cylindrical pile, which in turn forms a water-stop curtain, allowing the polluted groundwater to flow completely through the permeable bioreactor wall based on piezoelectric materials.

[0056] The extraction pump pressure is within the range of 1-10 MPa. The groundwater extraction flow rate is controlled by adjusting the pressure, with a high flow rate of 5-10 m / s and a low flow rate of 0.1-0.5 m / s. The extraction pump draws groundwater from a specified depth of soil, and a periodically controlled valve regulates the extraction flow rate, thereby transmitting pulsed hydraulic pressure to the piezoelectric material. A pre-embedded gas transport pipeline connects to the air inlet of the array hollow fiber membrane module, and the connection is wrapped with polyurethane material to improve airtightness and durability. The piezoelectric material modules and the array hollow fiber membrane modules are arranged alternately to form the main structure of the permeable bioreactor wall. The piezoelectric material modules are close to the soil at both ends, and the number and order of the middle section of the permeable bioreactor wall can be adjusted according to the site's hydrogeological conditions, site size, and pollutant removal effect. The surface of the array hollow fiber membrane is designed with a sinusoidal corrugated structure.

[0057] Example 2

[0058] A pesticide production plant decommissioning site (500 m × 1000 m) has a groundwater contaminated with multiple organic pollutants. A permeable bioreactor (400 m long, 2 m wide, and 10 m deep) is installed at the groundwater runoff point. An extraction well (6 m deep) is constructed upstream of the contamination plume. An air pump and an array of hollow fiber membrane modules are connected via a gas transport pipeline. The air pump is equipped with a solar power system, requiring no external current and enabling long-term microbubble aeration.

[0059] Open the hydraulic-electric control valve 7 and start the extraction pump 4 to begin extracting groundwater contaminated with compound organic pollutants at a depth of 6 m. Control the groundwater flow velocity at 0.2 m / s by observing the water flow velocity gauge 8, and continue water intake for at least 30 minutes to ensure the soil in the soil sample chamber is saturated with water. Then, under the control of the water flow velocity gauge 8, switch the groundwater flow velocity between 0.2 m / s and 5 m / s with a switching cycle of 10 minutes to achieve a periodic pulsed groundwater flow field. During each cycle, sample the groundwater flowing through the reaction wall to monitor water quality indicators and pollutant concentrations.

[0060] The dissolved oxygen in contaminated groundwater is usually below 1 mg / L, which is relatively hypoxic. Turning on the air pump 5 pumps air into the hollow fiber membrane 2 in the array to replenish the dissolved oxygen concentration in the groundwater in the form of microbubbles, so that the dissolved oxygen concentration in the biological function chamber is maintained at a level of 4 to 6 mg / L, providing sufficient oxygen for aerobic microorganisms.

[0061] After 90 days of application of the permeable bioreactor device of this invention for removing complex organic pollutants in groundwater at a decommissioned chemical plant site, the concentration of complex organic pollutants decreased from an initial 2.4 ± 2.54 mg / L to 0.03 ± 0.01 mg / L, demonstrating the enhanced bioremediation efficacy of this invention for groundwater contaminated with complex organic pollutants.

[0062] Example 3

[0063] A fine chemical plant site suffered severe groundwater pollution due to improper wastewater management during long-term operation. The pollutants mainly included various heavy metal ions and organic pollutants. The groundwater pollution was widespread and the pollutant concentration was high, posing a potential threat to the surrounding environment and residents' health. Therefore, a piezoelectric-enhanced permeable aerobic bioreactive wall (PRB) integrating physical, chemical, and biological remediation technologies was selected to treat the contaminated site. Drilling and water quality monitoring determined the distribution and concentration of pollutants. Based on hydrogeological surveys, the main flow direction of the groundwater was determined. A 100 m long, 1 m thick, and 8 m deep design was used to ensure complete coverage of the contaminated layer. Piezoelectric materials were mixed into the filling material at a ratio of KNN:BT:PVDF = 0.2:0.2:2. Gravel, ceramsite, and activated carbon were also used to ensure sufficient permeability and adsorption capacity. Iron filings were used to promote the reduction reaction of heavy metals. A 2 m wide and 8 m deep trench was excavated along the groundwater flow direction, ensuring trench stability and preventing collapse. Extraction wells and pump 4 were installed downstream of the reactive barrier, with a well spacing of 30 m, to ensure periodic regulation of the groundwater flow rate, thereby controlling the speed at which groundwater flows through the reactive barrier. The groundwater, contaminated with complex organic pollutants, contained metal ions such as copper (2.12 μg / L), zinc (5.03 μg / L), aluminum (13.73 μg / L), manganese (45.79 μg / L), and lead (0.61 μg / L), which were detrimental to the growth and metabolism of functional microorganisms. When the groundwater flowed through the reactive barrier, the piezoelectric material 1 deformed due to the hydraulic pressure generated by the water flow, generating a local electric field. This local electric field promoted the reduction reaction of heavy metal ions, forming insoluble precipitates that were fixed within the reactive barrier, reducing the concentration of heavy metals in the groundwater. Simultaneously, the reduction of heavy metal ions provided electron donors for the microorganisms, accelerating biodegradation. The total removal rate of metal ions in the groundwater reached 93.6%, and the total concentration of organic pollutants was reduced by more than 70%, meeting environmental safety standards.

[0064] The specific embodiments shown above provide a detailed description of how the present invention solves the problems existing in the prior art, proposes solutions, and demonstrates its effectiveness. The above descriptions are merely specific embodiments of the present invention and should be understood as including any modifications, equivalent substitutions, and improvements made in accordance with the spirit of the invention within the scope of protection of the present invention.

Claims

1. A permeable aerobic bioreactor wall enhanced by piezoelectric effect, characterized in that: The reactive wall includes a piezoelectric material module, an array of hollow fiber membrane modules, an extraction pump, an air pump, a rotor flow meter, a hydraulic-electric control valve, and a water flow velocity meter. The piezoelectric material module and the array of hollow fiber membrane modules are arranged alternately to form the main body of the permeable bioreactor wall, with the piezoelectric material module close to the soil at both ends. The air pump is connected to the air inlet of the hollow fiber membrane module via a gas transport pipeline, and the rotor flow meter is installed on the gas transport pipeline. The extraction pump is located upstream of the entire reaction wall and is connected to the groundwater source through a pipeline. The hydraulic electric control valve is installed on the outlet pipe of the extraction pump, and the water flow rate meter is set in the pipeline section downstream of the hydraulic electric control valve. The piezoelectric material is a composite piezoelectric material, which is prepared by adding KNN and BT microparticles to PVDF slurry and using additive manufacturing technology of "layer-by-layer manufacturing". The mass ratio of KNN, BT and PVDF is 0.1-0.5:0.1-0.5:1-3.

2. The piezoelectric effect-enhanced permeable aerobic bioreactor wall according to claim 1, characterized in that: The piezoelectric material and the stainless steel perforated plate form a piezoelectric material module, with the stainless steel perforated plate providing support and positioning to both sides of the piezoelectric material.

3. The piezoelectric effect-enhanced permeable aerobic bioreactor wall according to claim 1, characterized in that: The array hollow fiber membrane module is composed of multiple hollow fiber membranes arranged closely in an array. Each array of hollow fiber membranes has a uniform thickness and is positioned by a slot.

4. The piezoelectric effect-enhanced permeable aerobic bioreactor wall according to claim 1, characterized in that: The bottom and sides of the permeable bioreactor wall have pre-set slots for positioning piezoelectric materials and hollow fiber membranes in the array.

5. The piezoelectric effect-enhanced permeable aerobic bioreactor wall according to claim 1, characterized in that: Hollow fiber membrane filaments arranged horizontally are tightly bonded and fixed on an array of hollow fiber membrane frames to form an array of hollow fiber membranes. Several arrays of hollow fiber membranes form a hollow fiber membrane module, which is bonded to a piezoelectric material module to form a unit. PM-PRBB is composed of several of the above units.

6. The piezoelectric effect-enhanced permeable aerobic bioreactor wall according to claim 1, characterized in that, The bottom of the permeable bioreactor wall should be connected to the upper layer of the first weakly permeable layer. At the same time, cement is sprayed and cut into the soil at a certain pressure through high-pressure jet grouting on both sides of the bioreactor wall. The cement is mixed with the soil to form a cylindrical pile, which in turn forms a water-stop curtain, allowing the polluted groundwater to flow completely through the permeable bioreactor wall based on piezoelectric materials.

7. The piezoelectric effect-enhanced permeable aerobic bioreactor wall according to claim 1, characterized in that, The extraction pump pressure is in the range of 1-10 MPa. The groundwater extraction flow rate is controlled by adjusting the pressure. The high liquid flow rate is 5-10 m / s, and the low liquid flow rate is 0.1-0.5 m / s.

8. The piezoelectric effect-enhanced permeable aerobic bioreactor wall according to claim 1, characterized in that, The surface of the hollow fiber membrane in the array is configured with a sinusoidal corrugated structure.

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