Intelligent controlled electric geomembrane barrier system and its construction and operation method

Abstract

The application discloses an intelligent control electric geotechnical barrier system and a construction and operation method thereof, characterized by comprising an electric geotechnical barrier device and an intelligent control device, wherein the electric geotechnical barrier device comprises a cathode row and an anode row arranged vertically and in parallel, the cathode row comprises at least two cathode electrode plates and a plurality of cathode conductive cores wrapped in the cathode electrode plates and distributed at equal intervals, and the gap between the two adjacent cathode electrode plates is filled with a permeable reaction wall; the cathode row comprises at least two anode electrode plates and a plurality of anode conductive cores wrapped in the anode electrode plates and distributed at equal intervals, and the gap between the two adjacent anode electrode plates is filled with an anode backfill soil; and the intelligent control device comprises a power module and a monitoring and control module, and the advantage is that the active interception, in-situ repair and intelligent control can be combined, and the efficient, durable and intelligent interception and repair of groundwater pollutants can be realized.

Description

Technical Field

[0001] This invention belongs to the field of environmental geotechnical engineering and porous media pollutant migration control, and in particular relates to an intelligent control electric geotechnical barrier system and its construction and operation method. Background Technology

[0002] Heavy metal pollutants, such as lead, cadmium, mercury, and chromium, are highly toxic, persistent, and bioaccumulative. Once they seep into underground aquifers, they form migratory pollution plumes, posing a long-term and serious threat to groundwater safety and human health. Due to the complexity and unseen nature of the underground environment, pollution plumes spread widely and are extremely difficult to remediate. Therefore, constructing a long-term, effective, and stable interception barrier between pollution sources and downstream sensitive receptors (such as drinking water sources, rivers, and lakes) is a key technical challenge that urgently needs to be addressed in the field of environmental geotechnical engineering.

[0003] Currently, underground pollution interception barriers are mainly divided into two categories: passive and active. Passive barriers are the most traditional method, relying primarily on physical isolation. Typical forms include vertical impermeable walls, such as cement-soil continuous walls, bentonite isolation walls, or the laying of high-density polyethylene (HDPE) geomembranes and other impermeable materials. While these barriers can theoretically form a physical barrier, they suffer from several insurmountable drawbacks in practical applications. First, due to limitations imposed by complex geological conditions (such as fissures and lenses) and construction techniques, the continuity and integrity of the barrier cannot be absolutely guaranteed; even minor construction defects can become dominant seepage channels. Second, the materials of these barriers will age, corrode, or physically break down over time, posing a risk of long-term failure. Most importantly, they only delay the migration of pollutants; pollutants will continue to accumulate in front of the barrier, forming a more concentrated pollution pool. This not only fails to eliminate pollution but also increases long-term environmental risks.

[0004] To overcome the shortcomings of passive barriers, electro-geometry (EKG), which actively applies electric fields, has been applied to the remediation of contaminated sites. EKG induces various complex electro-hydraulic-chemical coupling effects by applying a direct current electric field to the subsurface soil medium, the most crucial of which is electroosmotic flow. The formation mechanism of electroosmotic flow originates from the interfacial electrochemical properties between the soil particle surface and pore water. Under most natural pH conditions, soil particles (such as clay and silt) generally carry a negative charge due to isomorphous substitution or dissociation of surface groups; these negative charges attract cations (such as potassium ions) in the pore water. + Na + Ca 2+This process forms a diffused double layer with a net positive charge on the particle surface. When a DC electric field is applied, this positively charged hydrated ion layer is driven by the electric field force to move as a whole towards the negative electrode (cathode), thereby achieving the purpose of enriching heavy metal ions at the cathode. To solve this inevitable cathode enrichment problem, existing electrokinetic remediation technologies mainly have two approaches: one is to use chemical means (such as injecting chelating agents) to change the ion charge to achieve reverse migration; the other is to set up physical or chemical trapping units (such as permeable reactive walls) in front of the cathode to fix the enriched ions. However, it must be clearly pointed out that, regardless of the intensification methods used, the essence and ultimate goal of these technologies is still the remediation of already contaminated areas, that is, to reduce the total amount of pollution through high-intensity, short-cycle cleanup operations.

[0005] Permeable reactive barriers (PRBs) are another promising in-situ remediation technology. Their core advantage lies in their ability to degrade or immobilize pollutants in situ, achieving true pollution remediation. PRBs create a porous reaction zone by excavating trenches underground and filling them with reactive materials such as zero-valent iron, activated carbon, and zeolite, allowing groundwater to flow through. When groundwater carrying pollutants passes through, the pollutants undergo physical adsorption, chemical precipitation, or redox reactions with the reactive materials, thus being removed from the aqueous phase. PRB technology is considered a green and sustainable remediation method due to its advantages such as requiring no external energy, low operating and maintenance costs, and long-term stable operation. However, the application of traditional PRB technology is also limited by a key prerequisite: its treatment efficiency and effectiveness heavily depend on the natural hydraulic gradient and flow velocity of the groundwater. In sites with small hydraulic gradients and slow flow velocities (such as in clay or silt strata), the flux of pollutants reaching the reactive barrier is extremely low, resulting in extremely long remediation cycles; in some cases, groundwater may even bypass the PRB, rendering it completely ineffective. Therefore, how to proactively and efficiently transport pollutants to the PRB reaction zone is a key bottleneck in maximizing its advantages in in-situ remediation and expanding its application scope.

[0006] In summary, existing technologies in the field of groundwater heavy metal pollution interception and remediation still have the following shortcomings: (1) Passive barriers (such as isolation walls and padding systems), although these technologies can play a physical barrier role, have problems such as low interception efficiency, easy to generate weak points and fail, and inability to treat the intercepted pollutants in situ, and there is a risk of long-term failure; (2) Active electro-remediation technology, although this technology can actively migrate pollutants, is usually for short-term high-intensity treatment of contaminated sites. If it is used as a long-term barrier, there are problems such as excessive energy consumption and lack of adaptive control; (3) Although permeable reactive barrier (PRB) technology can remediate pollutants in situ, its interception efficiency is completely limited by the natural migration speed of the pollution plume and hydraulic conditions, lacks the ability to actively capture pollutants, and has a long remediation cycle and uncontrollable effect; In the existing technology system, there is no intelligent defense barrier that can combine active interception and in-situ remediation functions and can be implemented in an engineering manner. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an intelligent control electric geotechnical barrier system that combines active interception, in-situ remediation and intelligent regulation, as well as its construction and operation method, which can achieve efficient, durable and intelligent interception and remediation of groundwater pollutants.

[0008] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: an intelligent control electric geotechnical barrier system, comprising an electric geotechnical barrier device and an intelligent control device, wherein the electric geotechnical barrier device comprises a vertically arranged and parallelly arranged cathode row and anode row, wherein the cathode row is located upstream of the anode row, and the cathode row comprises at least two cathode electrode plates and a plurality of equally spaced cathode conductive cores wrapped within the cathode electrode plates, wherein the gap between two adjacent cathode electrode plates is filled with a permeable reactive wall; the anode row comprises at least two anode electrode plates and a plurality of equally spaced anode conductive cores wrapped within the anode electrode plates, wherein the gap between two adjacent anode electrode plates is filled with anode backfill soil.

[0009] The intelligent control device includes a power supply module and a monitoring and control module. The positive output terminal of the power supply module is electrically connected to the anode conductive core, and the negative output terminal of the power supply module is electrically connected to the cathode conductive core. The monitoring and control module is used to collect and analyze the heavy metal ion concentration in the anode row region in real time, and send control commands to the power supply module. The power supply module adjusts the electric field strength applied between the anode row and the cathode row according to the control commands.

[0010] The side closer to the pollution source is the cathode row, and the side farther from the pollution source is the anode row. The unique feature of the cathode row is that it is not simply an electrode, but rather an integrated "enrichment-capture-reaction" composite zone formed by filling the cathode with the reactive material of the permeable reactive barrier. The anode row is formed by the combined action of the anode and the backfill soil in between. This asymmetrical electrode arrangement, with the cathode upstream and the anode downstream, is key to the high-efficiency interception of this invention. Its core lies in the generation of a strong reverse electroosmotic flow from downstream to upstream between the anode and cathode rows after activation. This hydraulic barrier directly counteracts and hinders the natural migration of pollutants. Secondly, the electric field induces the electromigration of heavy metal cations. Positively charged heavy metal cations are driven by the electric field force to actively migrate towards the upstream cathode region.

[0011] Furthermore, both the cathode electrode plate and the anode electrode plate are provided with multiple reinforcing ribs extending along their sides.

[0012] Furthermore, both the anode conductive core and the cathode conductive core are composed of at least one of a conductive polymer, a carbon fiber mesh, or an inert metal mesh. The conductive core is preferably made of a chemically stable material with good conductivity and a certain structural strength.

[0013] Furthermore, the reaction material of the permeable reactive wall is composed of at least one of zero-valent iron, activated carbon, zeolite, biochar, or a combination thereof, used for in-situ adsorption and degradation of heavy metal pollutants enriched in the cathode drain area. Zero-valent iron (ZVI) is used to remove heavy metal ions through reduction; granular activated carbon (GAC) is used to remove pollutants through physical adsorption; natural or modified zeolite is used to immobilize heavy metal ions through ion exchange; or biochar has the function of both adsorption and providing attachment sites for microorganisms.

[0014] Furthermore, the monitoring and control module includes an ion concentration sensor and a data analysis and processing terminal. The ion concentration sensor is arranged in a three-dimensional array on the anode row. The ion concentration sensor collects heavy metal ion concentration data at different depths and positions of the anode row in real time and transmits it to the data analysis and processing terminal. The data analysis and processing terminal receives and analyzes the heavy metal ion concentration data, compares the maximum heavy metal ion concentration with a preset threshold, and generates control commands based on the analysis results to adjust the current of the power module in real time.

[0015] Furthermore, the data analysis and processing terminal compares the received real-time heavy metal ion concentration data with preset upper and lower thresholds. When the maximum heavy metal ion concentration is higher than the upper threshold, it sends a command to the power module to increase the output power and enhance the electric field strength. When the maximum heavy metal ion concentration is continuously lower than the lower threshold, it sends a command to the power module to reduce the output power or enter a low-power maintenance mode. If the heavy metal ion concentration is between the upper and lower thresholds, the current output power remains unchanged.

[0016] Furthermore, the ion concentration sensor comprises at least three monitoring points along the vertical direction of the anode array: a top sensor located near the groundwater level, a middle sensor located at the core depth of pollutant migration, and a bottom sensor located at the bottom of the aquifer near the impermeable bedrock. Several ion concentration sensors are evenly distributed along the horizontal direction of the anode array. This three-dimensional, multi-angle monitoring strategy is particularly important for understanding the complex migration paths that heavy metal pollutants may form in heterogeneous aquifers.

[0017] Furthermore, the power module includes an adjustable DC power supply, a fuse for circuit overload protection, and an ammeter for monitoring the current in the circuit, wherein the fuse and the ammeter are connected in series in the power supply circuit.

[0018] This invention also provides a method for constructing and operating the above system, comprising the following steps:

[0019] Step 1, Site Construction: In the underground aquifer of a heavy metal contaminated site, vertical cathode and anode rows are deployed in the downstream area of ​​the heavy metal pollutant migration zone, wherein the cathode rows are deployed on the upstream side of the anode rows to define the electrodynamic geotechnical barrier zone, and a permeable reactive wall is constructed in the gaps between the cathode rows.

[0020] Step 2, System Connection and Initialization: Connect the cathode and anode blocks to the power module respectively, complete the signal connection between the ion concentration sensor and the data analysis and processing terminal, perform system initialization, and set the initial operating parameters of the power module and the upper and lower limit thresholds of the pollutant concentration;

[0021] Step 3, Active Interception and In-situ Remediation: Activate the power module to establish a DC electric field between the cathode and anode rows. The migration of the pollution plume is blocked by electroosmotic flow, and charged heavy metal ions are enriched in the cathode row area through the electromigration effect, and then adsorbed or degraded in-situ through the permeable reactive wall.

[0022] Step 4, Intelligent Control: While Step 3 is being performed, the concentration of heavy metal ions in the anode row area is collected by the ion concentration sensor. The data analysis and processing terminal receives the data and compares the maximum collected heavy metal ion concentration with the preset upper and lower thresholds of the ion concentration. A control command is generated and sent to the power module to dynamically adjust the intensity of the DC electric field.

[0023] Step 5, System Maintenance: Continue to execute steps 3 and 4, regularly sample and monitor the protected water body downstream of the electro-hydroelectric barrier to evaluate the interception effect of the electro-hydroelectric barrier, and regularly inspect or replace the reactive material in the permeable reactive wall.

[0024] This invention constructs an active pollution barrier based on electrodynamic technology. Its core interception principle lies in the DC electric field applied to the soil: on one hand, it generates an electroosmotic flow from the anode to the cathode, creating a hydraulic barrier against the direction of pollutant migration, effectively hindering its convection and diffusion; on the other hand, it drives the electromigration of charged heavy metal ions, controlling them in the upstream cathode region and preventing their downstream diffusion. Through this synergistic effect, positively charged heavy metal ions are enriched in the cathode region and adsorbed or degraded in situ by a permeable reactive barrier. This efficiently and actively constructs an electrodynamic seepage barrier between the pollution source and the protected target, effectively blocking the migration of pollution plumes.

[0025] Compared with the prior art, the advantages of the present invention are as follows:

[0026] (1) A fundamental shift from passive isolation to active interception has been achieved. By constructing an electroosmotic barrier, this invention can actively counteract the migration pressure of pollution plumes. Its interception capability is driven by an electric field, eliminating the dependence of traditional passive barriers (such as continuous walls) and PRB technology on the natural hydraulic conditions of the site, and significantly improving the interception reliability under various geological conditions.

[0027] (2) It endows the barrier with the ability to reduce pollutant flux, thus avoiding the infinite accumulation of pollutants at the barrier front. Unlike the idea that only has a blocking function, the present invention can fix or degrade the intercepted pollutants in situ by integrating a permeable reactive wall at the cathode. This fundamentally solves the risk of bypassing or breaking through the flow caused by long-term accumulation of pollutants.

[0028] (3) Improved energy efficiency and economy of barrier system operation. The intelligent control system can dynamically adjust the electric field strength required to maintain the barrier based on the real-time monitoring of pollutant concentration within the barrier. This adaptive operation mode ensures that the system outputs peak power only when necessary, and maintains effective interception with minimal energy consumption when the pollution load is low, thereby avoiding unnecessary energy waste.

[0029] (4) Enhanced long-term service capability and maintainability of the barrier system. The replaceable or regenerable design of the permeable reactive barrier solves the technical problem that the entire barrier becomes unusable once the traditional landfill reactive material fails. This allows the barrier of this invention to be fully functional through regular maintenance, ensuring its effectiveness and sustainability as a long-term defense project.

[0030] (5) The electric geotechnical barrier system proposed in this invention integrates active hydraulic interception, in-situ pollutant removal and intelligent process control, filling the gap in the field of active and intelligent pollution defense. Compared with existing single or passive technologies, this invention has made significant technological progress in terms of interception efficiency, operational stability and economy.

[0031] In summary, the present invention provides an intelligent control electric geotechnical barrier system and its construction and operation method. By constructing an active hydraulic barrier with reverse electroosmotic flow as its core, and combining the in-situ treatment capability of the permeable reactive wall with intelligent control logic that provides real-time parameter feedback, the system significantly improves the interception efficiency of heavy metal pollutants while achieving efficient, energy-saving, and long-term stable operation of the barrier. Attached Figure Description

[0032] Figure 1 A schematic diagram of the overall structure of an intelligently controlled electric geotechnical barrier system;

[0033] Figure 2 A three-dimensional schematic diagram of the electrode arrangement structure of an electric geobarrier device;

[0034] Figure 3 This is a schematic diagram of the anode busbar structure;

[0035] Figure 4 This is a schematic diagram of the cathode array structure;

[0036] Figure 5 A schematic diagram of the closed-loop feedback control process of an intelligent control device;

[0037] The following labels are used in the diagram: 1. Heavy metal pollution source; 2. Pollution plume; 3. Aquifer; 4. Impermeable bedrock; 5. Groundwater level; 6. Cathode packer; 7. Fuse; 8. Adjustable DC power supply; 9. Ammeter; 10. Power control line; 11. Anode packer; 12. Sensor signal data line; 13. Data analysis and processing terminal; 14. Protected water body; 15. Anode backfill soil; 16. Ion concentration sensor; 17. Electro-mechanical barrier zone; 18. Permeable reactive barrier; 19. Cathode conductive core; 20. Cathode electrode plate; 21. Anode conductive core; 22. Anode electrode plate. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. These embodiments are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0039] Specific Implementation Example 1: An intelligently controlled electric geotechnical barrier system.

[0040] The system as a whole includes an electrically powered geotechnical barrier device constructed in situ downstream of the pollutant migration path in the underground aquifer 3 and an intelligent control device centrally located on the ground.

[0041] like Figure 1 and Figure 2 As shown, the electric geotechnical barrier device is the core execution unit of this invention. The electric geotechnical barrier device includes a cathode row 6 and an anode row 11 arranged in parallel array. The cathode row 6 is located upstream of the anode row 11, that is, closer to the heavy metal pollution source 1.

[0042] like Figure 3 As shown, the cathode array 6 includes at least two cathode electrode plates 20 with good conductivity and rigidity, and a number of equally spaced cathode conductive cores 19 wrapped within the cathode electrode plates 20. The gap between two adjacent cathode electrode plates 20 is filled with a permeable reactive wall 18.

[0043] like Figure 4 The anode row 11 includes at least two anode electrode plates 22 with good conductivity and rigidity, and several anode conductive cores 21 distributed at equal intervals within the anode electrode plates 22. The gap between two adjacent anode electrode plates 22 is filled with anode backfill soil 15. The area between the cathode row 6 and the anode row 11 is the soil within the electro-geomechanical barrier zone 17.

[0044] like Figure 1 As shown, the intelligent control device is the core of this invention, responsible for providing power to the entire system and enabling automated operation. This device mainly consists of a power supply module and a monitoring and control module. The power supply module primarily includes an adjustable DC power supply 8. The positive output terminal of the adjustable DC power supply 8 is connected to the anode conductive core 21 via a cable, and the negative output terminal is connected to the cathode conductive core 19 via a cable. The monitoring and control module is used to collect and analyze the heavy metal ion concentration in the anode row 11 region in real time and send control commands to the DC power supply. The DC power supply adjusts the electric field strength applied between the anode row 11 and the cathode row 6 according to the control commands. The power supply module also includes a fuse 7 and an ammeter 9. The rated current of the fuse 7 is set according to the maximum safe operating current of the system, used to automatically disconnect the circuit to protect the power supply and other equipment in the event of a short circuit or abnormal current overload. The ammeter 9 is used to monitor the total current flowing through the system in real time and continuously. The fuse 7 and the ammeter 9 are connected in series in the power supply circuit.

[0045] In this specific embodiment, the monitoring and control module is an integrated intelligent unit, mainly including a data analysis and processing terminal 13 and an ion concentration sensor 16 installed on the anode bar 11. Figure 5 As shown, the ion concentration sensor 16 uploads real-time data to the data analysis and processing terminal 13 via the sensor signal data line 12. The data analysis and processing terminal 13 compares the received real-time ion concentration data with preset upper and lower thresholds. When the maximum heavy metal ion concentration exceeds the upper threshold, it sends a command to the power module to increase the output power and enhance the electric field strength. When the maximum heavy metal ion concentration remains below the lower threshold, it sends a command to the power module to reduce the output power or enter a low-power maintenance mode. If the ion concentration is between the upper and lower thresholds, the current output power is maintained, forming a complete closed-loop feedback control loop.

[0046] In this specific embodiment, both the cathode electrode plate 20 and the anode electrode plate 22 are integrally formed from conductive polymer through an extrusion process, with multiple ribs extending from both sides. In this design, the cathode electrode plate 20 and the anode electrode plate 22 serve as the main structural supports and long-distance current paths, while the reinforcing ribs significantly increase the specific surface area of ​​the electrodes. This integrated ribbed structure design has significant technical advantages. In terms of physical properties, the reinforcing ribs greatly improve the cross-sectional moment of inertia of the electrode plate, thereby enhancing its overall stiffness and bending strength, providing structural assurance for rapid on-site construction methods. In terms of electrochemical and hydraulic properties, the increased specific surface area promotes a more uniform current density distribution between the electrodes and the porous medium, helping to form a more homogeneous electric field within the barrier zone, thus improving the overall operational efficiency of the electro-mechanical barrier system.

[0047] In this specific embodiment, the cathode conductive core 19 and the anode conductive core 21 serve as the core conductors for current transmission, and their material selection requires comprehensive consideration of conductivity, electrochemical stability, mechanical strength, and economy. In this embodiment, inert metal mesh (such as titanium metal mesh with a noble metal oxide coating) or flexible graphite felt can be used. Titanium metal mesh has excellent conductivity and resistance to anodic oxidation corrosion, making it an ideal choice for the anode core. Graphite felt is a feasible alternative due to its high cost-effectiveness, good flexibility, and chemical stability. In other embodiments, emerging conductive polymers or high-strength carbon fiber meshes and other advanced materials can also be used to adapt to different engineering needs and environmental conditions.

[0048] In this specific embodiment, the permeable reactive barrier 18 is integrated with the cathode array 6, and the selection of its reactive materials employs a targeted design strategy. In the early stages of system design, sampling and analysis of the heavy metal pollution source 1 are necessary to identify the types and chemical characteristics of the main target pollutants, and based on this, the most efficient reaction medium is selected. For example, in treating lead (Pb)... 2+ ), cadmium (Cd 2 + When the pollutants are mainly divalent cations, natural or modified zeolites with high cation exchange capacity can be selected to capture and fix the pollutants through their ion exchange. Through this targeted material selection, it can be ensured that the PRB has the highest removal efficiency and the largest treatment capacity for the target pollutants, thereby optimizing the repair function of the entire barrier system.

[0049] In this specific embodiment, the core of the monitoring and control module is an array of ion concentration sensors 16 arranged in a three-dimensional array to overcome the spatial heterogeneity of the underground pollution plume 2 migration. Specifically, the ion concentration sensors 16 are arranged along different key vertical depths (such as groundwater level, pollution core area, and near bedrock), such as... Figure 3 As shown, specifically: In the vertical direction, the array along the anode row 11 includes at least three monitoring points at key depths: a top sensor, deployed near the groundwater level 5, designed to capture pollutants that may migrate rapidly along the water table; a middle sensor, deployed in the predicted core concentration area of ​​the pollution plume 2 based on preliminary site survey results, to reflect changes in the main pollution load; and a bottom sensor, deployed at the bottom of the aquifer 3 near the impermeable bedrock 4, to monitor the pollutant front migrating along the bottom due to gravity settling or the dominant channel effect. In the horizontal direction, multiple sensor arrays are deployed at predetermined intervals to monitor changes in pollutant concentrations in the barrier anode area in real time.

[0050] To ensure the long-term stable operation of the sensor array in harsh underground environments, this invention employs targeted installation methods for sensors in different locations. For the ion concentration sensors 16 installed on the anode electrode plate 22, an embedded installation method that balances physical protection and measurement accuracy is used. Each ion concentration sensor 16 is not directly exposed to the soil but is fixed within a groove between the reinforcing ribs of the anode electrode plate 22. This design utilizes a robust electrode plate structure to provide effective physical shielding for the sensor, preventing damage during construction. Simultaneously, the sensing surface of the ion concentration sensor 16 directly contacts the soil within the electro-mechanical barrier zone 17 through the groove opening, maintaining good hydraulic communication with the surrounding soil, thereby ensuring the real-time nature and representativeness of the measurement data. For the ion concentration sensors 16 installed inside the barrier zone, an independent drilling method is used for installation. Monitoring holes are drilled at predetermined monitoring points in the soil area between the anode row 11. Multiple sensors at different predetermined depths (top, middle, bottom) are lowered to the designated positions at once. Then, the sensors are backfilled and sealed with permeable sand or bentonite particles to ensure close contact and hydraulic communication between the sensors and the surrounding soil.

[0051] Regarding sensor selection, this invention adopts a targeted selection strategy. Specifically, for example, in a copper mine contaminated site, a copper ion selective electrode (Cu-ISE) can be preferred as the core monitoring element; while in a lead- and zinc-contaminated site, a multi-parameter water quality probe integrating lead ion selective electrodes (Pb-ISE) and zinc ion selective electrodes (Zn-ISE) can be selected to achieve simultaneous monitoring of multiple key pollutants.

[0052] In terms of signal connection, the signal cables of multiple sensors arranged along the same vertical direction are bundled and converged into a single vertical bus. Subsequently, multiple signal buses are connected in parallel to a main signal cable, namely the sensor signal data line 12, and finally uniformly connected to the ground-based data analysis and processing terminal 13. By fusing and analyzing sensor data from different depths and horizontal positions, the control system can form a comprehensive and three-dimensional understanding of the pollutant concentration field at the barrier front, thereby making more precise control decisions. The adjustable DC power supply 8 is a programmable adjustable DC regulated power supply, whose output current adjustment range can be set within a wide range according to the site size, soil resistivity, and remediation targets.

[0053] The aforementioned electrically powered geotechnical barrier system not only utilizes electroosmosis and electromigration to construct an active and highly efficient interception barrier, but also coordinates with the permeable reactive wall 18 integrated into the cathode drain 6 to perform in-situ remediation of intercepted pollutants. By organically combining active interception, in-situ treatment, and intelligent control, the efficiency, reliability, and economy of the entire interception and remediation process are optimized to the greatest extent. Experimental and simulation results show that, compared with technologies that only have interception or passive remediation functions, this invention significantly improves the efficiency of pollutant interception and removal while dynamically adjusting energy consumption according to on-site conditions, ensuring the long-term stability of the barrier in complex and changing on-site environments and its cost-effectiveness throughout its entire life cycle.

[0054] Specific Embodiment 2: Construction and operation method of the barrier system for groundwater pollution interception based on Specific Embodiment 1 above.

[0055] Step 1, Site Construction and Investigation: Based on the preliminary hydrogeological investigation results, the migration path, range, and core depth of heavy metal pollution plume 2 were analyzed. Downstream of the pollution plume 2 migration path, an anode row 11 and a cathode row 6 were vertically installed using drilling and other methods. The cathode row 6 was installed upstream of the anode row 11. Subsequently, a permeable reactive barrier 18 was constructed in the gaps between the cathode rows 6 by grouting or filling.

[0056] Step 2, System Connection and Initialization: Connect the conductive cores of anode row 11 in parallel via the anode bus cable, and connect the conductive cores of cathode row 6 in the same way via the cathode bus cable; connect the two bus cables to the positive and negative output terminals of the power module respectively; complete the signal connection between the ion concentration sensor array 16 deployed along the anode area and the control module; start the control module, initialize the system, and set parameters such as the initial output current of the power supply and the upper and lower limit control thresholds of pollutant concentration on the data analysis and processing terminal according to the site conditions and remediation goals.

[0057] Step 3, Active Interception and In-situ Remediation Start-up: Start the power module, with the anode as the positive electrode and the cathode as the negative electrode, and apply a DC electric field between the electrodes to establish an active defense barrier; under the action of this electric field, electroosmotic flow begins to form, and at the same time, the electromigration effect begins to drive heavy metal cations; this process continuously and actively intercepts and enriches the pollutants at the front end of the pollution plume 2 into the cathode area, and makes them fully contact the reactive materials in the permeable reactive wall 18, so as to be adsorbed or degraded in situ.

[0058] Step 4: Intelligent Control and Unattended Operation: After the system enters stable operation, it switches to intelligent control mode. The three-dimensional sensor array continuously transmits the collected heavy metal ion concentration data to the data analysis and processing terminal 13. This multi-point real-time data is analyzed, and the maximum value of the collected heavy metal ion concentration is compared with a preset threshold. When the pollution load is determined to be increasing (e.g., the concentration exceeds the upper threshold), the system immediately and automatically increases the electric field strength. When the pollution load is determined to be decreasing (e.g., the concentration remains below the lower threshold), the system automatically reduces the electric field strength or switches to a low-power maintenance mode, achieving unattended adaptive operation throughout the entire process. When the concentration is between the upper and lower thresholds, the electric field strength remains unchanged.

[0059] Step 5, Long-term Operation and Maintenance: Continue to execute steps 3 and 4, and periodically sample and monitor the protected water body 14 downstream of the barrier to assess and verify the final interception effect of the barrier. Simultaneously, based on the theoretical saturation capacity of the PRB material and the system's cumulative treatment capacity, periodically inspect the reactive material in the permeable reactive wall 18, and replace or regenerate it as necessary to ensure the long-term effectiveness of the system.

[0060] The application of the methods in Specific Embodiment 3 and Specific Embodiment 2 is set in a farmland area downstream of an abandoned lead-zinc mine, where the groundwater has been severely contaminated by lead (Pb). 2+ ) and zinc (Zn 2+ The complex pollution necessitates the urgent construction of a barrier to prevent the pollution plume from further spreading to downstream drinking water sources. The specific steps are as follows:

[0061] Step 1: Preliminary Preparation and Parameter Setting

[0062] (1) Site survey and scheme design

[0063] First, a comprehensive hydrogeological survey of the target contaminated site is conducted before any field work is initiated. In this embodiment, through methods such as borehole sampling, on-site pumping tests, and resistivity tomography (ERT), the main aquifer 3 was determined to be a medium sand layer with an average thickness of 8 meters and a permeability coefficient of approximately 1.5 × 10⁻⁶. -4 The groundwater flow rate is approximately 0.1 m / s, and the natural flow velocity is approximately 0.1 m / day. The bottom of aquifer 3 is located at an elevation of -10 meters, below which is a thick layer of clay, which can serve as natural impermeable bedrock 4.

[0064] Secondly, by deploying multiple monitoring wells in a grid pattern within the site and conducting multiple rounds of water sampling and chemical analysis, the three-dimensional spatial distribution of heavy metal pollution plume 2 was accurately depicted. The analysis results show that the core area (highest concentration area) of pollution plume 2 is concentrated at a depth of -4 to -6 meters underground, with lead (Pb) as the main pollutant. 2+ ) and zinc (Zn2+ The highest detected concentration of lead ions reached 1.2 mg / L. Finally, based on the above survey results, a barrier design was carried out. According to the determined mainstream direction of groundwater, the electro-mechanical geobarrier system of this invention was designed 50 meters downstream of the leading edge of pollution plume 2. To ensure sufficient reaction time and interception efficiency, the distance between the cathode row 6 and the anode row 11 in this embodiment was designed to be 2.0 meters. Considering the lateral width of pollution plume 2, the designed interception length of the barrier was set to 20 meters, and the effective treatment depth was 8 meters (i.e., penetrating the entire aquifer 3). Therefore, the effective cross-sectional area of ​​the entire barrier is 160 m². 2 .

[0065] (2) Selection of key materials for the system

[0066] Electrode materials: Considering the high chloride ion content and strong corrosiveness of groundwater, both the cathode conductive core 19 and the anode conductive core 21 are made of inert metals with high conductivity. The anode electrode plate 22 and the cathode electrode plate 20 are both made of a material that combines good conductivity, excellent corrosion resistance, and sufficient mechanical strength, such as conductive polymers or carbon fiber reinforced composites. The conductive core is responsible for receiving the current and distributing it evenly to the surrounding soil through its reinforcing ribbed electrode plate structure, while also providing structural rigidity and flow channels for the entire electrode array.

[0067] PRB reaction materials: targeting the primary lead (Pb) in the site. 2+ ), Zinc (Zn) 2+ To address the complex pollution, and considering the cost and long-term effectiveness of the materials, the reaction material for the permeable reactive wall 18 can be natural or modified zeolite with a high cation exchange capacity (CEC). Zeolite possesses a regular pore structure and numerous exchange sites, enabling it to efficiently capture and immobilize lead (Pb) migrating there through ion exchange. 2+ ) and zinc (Zn 2+ Ions are used to achieve in-situ fixation and removal.

[0068] Sensor selection: Since lead ions are far more toxic to the environment than zinc ions and are the key control target for this remediation, this embodiment selects a high-precision, high-selectivity lead ion selective electrode (Pb-ISE) as the core ion concentration sensor 16 to comprehensively monitor the hydrochemical environment of the barrier in real time with multiple parameters.

[0069] (3) Setting initial operating parameters and control thresholds

[0070] To maximize energy efficiency while ensuring effective interception, this embodiment sets the target average voltage gradient to 1.0 V / m, corresponding to a design constant voltage of 2.0 V. Based on soil conductivity test results and empirical data from similar projects, the expected current density during stable system operation is approximately 1.0 A / m. 2 The total current is estimated based on this current density, and all electrical components are configured according to this standard with a safety margin.

[0071] In the control software of the data analysis and processing terminal 13, key control thresholds for intelligent regulation are preset. The ultimate remediation goal of this embodiment is to stabilize the lead concentration in the downstream water body below 0.01 mg / L according to the Class III water standard of the "Groundwater Quality Standard". To achieve proactive and preventative control, the control threshold settings must allow for sufficient response margin. Therefore, this embodiment sets the following standards to be met: Upper limit alarm threshold: set at 0.08 mg / L. When the lead ion concentration detected at the front of the anode discharge 11 exceeds this value, it indicates that the pollution load is increasing significantly, and the system needs to immediately enter a high-load response mode. Lower limit maintenance threshold: set at 0.008 mg / L. When the monitored concentration remains stable below this value, it indicates that the barrier interception effect is very significant, and the system can safely switch to a low-power maintenance mode.

[0072] Step 2: On-site construction and system connection

[0073] (1) Construction of underground barrier devices

[0074] Measurement and layout, and equipment placement: Based on the design scheme determined in step 1, conduct precise measurement and layout at the construction site, and use a total station to mark the centerline position of each anode electrode plate 22 and cathode electrode plate 20. Select and place a tracked hydraulic vibratory hammer or static pressure implantation equipment suitable for the geological conditions.

[0075] Installation of the electrode plate array: A row-by-row, piece-by-piece construction sequence is adopted. The construction equipment vertically clamps the cathode electrode plate 20 and anode electrode plate 22, aligns them with the center line, and then smoothly and continuously implants them into the ground to the designed depth of -10 meters using high-frequency vibration or static pressure, forming the cathode row 6 and anode row 11. Throughout the installation process, real-time monitoring ensures that the verticality and planar position of the electrode plates are within the design tolerance range.

[0076] Simultaneous construction of the permeable reactive wall 18: During the installation of the cathode array 6, a simultaneous filling process is adopted. Specifically, after each cathode electrode plate 20 is installed, pre-prepared reactive material is immediately injected from bottom to top into the gap between it and the adjacent installed cathode electrode plate 20 until it is completely filled, thereby constructing a dense and continuous permeable reactive wall.

[0077] (2) Connection and initialization of the ground intelligent control device

[0078] Construction of the main circuit: First, connect all the anode conductive cores 21 outgoing terminals in the anode row 11 to a single anode bus cable in parallel via corrosion-resistant connectors, and then connect them to the main circuit via an ammeter 9 in series. Similarly, connect all the cathode conductive cores 19 outgoing terminals in the cathode row 6 to the cathode bus cable. Then, after leading these two bus cables to the ground control room, securely connect them to the positive and negative output terminals of the adjustable DC power supply 8. All outdoor connections undergo rigorous waterproofing and insulation treatment.

[0079] Signal and control loop establishment: The signal lines of the multi-point ion concentration sensor array 16 deployed on the anode row 11 are collected and connected to the data acquisition interface of the data analysis and processing terminal 13 via the sensor signal data line 12. At the same time, the remote communication port of the adjustable DC power supply 8 is connected to the control output interface of the data analysis and processing terminal 13 via the power control line 10 to establish a transmission link for control commands.

[0080] System software initialization settings: Finally, start the data analysis and processing terminal 13 and enter the control software interface. Based on the design values ​​determined by the site survey, enter and save the core parameters such as the system's initial operating mode, initial output voltage (0.5V), upper limit alarm threshold (0.08 mg / L) and lower limit maintenance threshold (0.008 mg / L) for lead ion concentration. After completing all settings, the system enters standby mode, ready to start.

[0081] Step 3: System Startup and Initial Debugging

[0082] The purpose of this step is to safely and smoothly start up the entire barrier system and to conduct preliminary verification of the accuracy of the online monitoring components, laying the foundation for subsequent long-term unattended operation. This step specifically includes two sub-steps: startup procedure and initial data calibration.

[0083] (1) Start-up procedure (phased voltage increase): Considering that a large electric geotechnical system may generate a large inrush current at the moment of startup due to the high initial ion concentration and high water content of the soil, this embodiment adopts a safe and reliable phased voltage increase procedure to start the system, as follows:

[0084] Phase 1 (Interface Startup and System Check): Start the system on the data analysis and processing terminal 13. First, apply a low voltage of 0.5V and maintain it for 24 hours. The main purpose of this phase is not to pursue the interception effect, but to allow the electrode and soil interface to slowly polarize and start up, and establish a stable conductive path. Monitor the initial current response through ammeter 9 and check for abnormal circuit connections such as short circuits or open circuits.

[0085] Phase 2 (Pre-run and Current Observation): After confirming that the system is working properly, increase the voltage to 1.0V; continue to run at this voltage and closely observe the changes in the reading of ammeter 9; the purpose of this phase is to confirm that the total current of the system can be stabilized below the design limit at a voltage close to the design operating condition, and that overload will not occur.

[0086] Phase 3 (Entering Design Operating Conditions): After the current stabilizes or begins to decrease, the voltage is eventually increased and stabilized at the design voltage of 2.0V. At this point, the system officially completes the startup and commissioning phase and enters the long-term intelligent control and operation phase.

[0087] (2) Initial data calibration

[0088] To ensure the accuracy and reliability of the online monitoring data, which forms the core basis of intelligent control, data calibration is required during the initial system startup phase (e.g., the first week). The specific procedure involves manually drilling and sampling in layers near the anode row 11 using a drill or soil sampler. The collected soil or pore water samples are then sent to a laboratory for precise analysis of lead and zinc ion concentrations using standard methods such as atomic absorption spectrometry (AAS) or inductively coupled plasma mass spectrometry (ICP-MS). Subsequently, the precise laboratory data is compared with the online readings of the ion concentration sensor 16 at the same time and depth. If systematic deviations are found, the sensor calibration curve is corrected on the data analysis and processing terminal 13 to ensure that the online monitoring system can accurately reflect the actual situation on-site over a long period.

[0089] Step 4: Stable Operation and Intelligent Control

[0090] After completing startup and initial debugging, the system officially entered a long-term, stable operation phase centered on intelligent control. This phase aims to achieve the most reliable interception effect with the lowest energy consumption.

[0091] (1) Steady-state operation

[0092] Under normal operating conditions, the system operates continuously at the set design voltage of 2.0V (corresponding to a voltage gradient of 1.0 V / m). During this stage, various operating parameters will exhibit certain regularity. The total system current will show a trend of slowly decreasing from the initial value and eventually stabilizing due to factors such as electrolysis gas production, ion migration, and gradual soil drying. Its approximate range is expected to fluctuate within a certain range in this embodiment. Meanwhile, the ion concentration reading of the ion concentration sensor 16 in the anode row 11 will remain stable at a low background value level under the effective interception of the barrier, that is, continuously below the set lower limit maintenance threshold of 0.008 mg / L.

[0093] (2) Intelligent control process

[0094] Pollution Impact Response: Due to a new leak from an upstream pollution source or heavy rainfall intensifying pollutant leaching, the concentration of the leading edge of pollution plume 2 suddenly increases. Data analysis and processing terminal 13, through ion concentration sensor 16 located in the middle of anode drain 11 (at a depth of -5 meters), detects that the lead ion concentration rapidly increases from 0.04 mg / L to 0.15 mg / L within a short period, exceeding the set upper alarm threshold of 0.08 mg / L. Data analysis and processing terminal 13 immediately determines that the system is facing a high pollution load impact and automatically triggers a high-load response mode. It sends a command to the power module via power control line 10, forcing a higher current input. This instantly enhances the intensity of electroosmotic flow, forming a stronger hydraulic barrier to ensure that pollutants cannot breach the barrier even under high concentration gradients.

[0095] Energy-saving mode switching: After operating in high-load response mode for a period of time, or during long-term stable operation, the data analysis and processing terminal 13 monitors that the readings of all ion concentration sensors 16 have fallen back and remained stable below the lower limit maintenance threshold of 0.008 mg / L for a preset period of time (e.g., 24 hours). The system determines that the current pollution load is extremely low and the barrier effect is significant, so full-power operation is not required. At this time, the system automatically switches to low-power maintenance mode. For example, the power supply method is switched from continuous power supply to an intermittent power supply strategy of "power on for 1 hour, power off for 4 hours". In this mode, the system only uses about 20% of the rated energy consumption to maintain an effective interception barrier by utilizing the hysteresis effect of electroosmotic flow, which greatly reduces the economic cost of long-term operation.

[0096] (3) Data recording and remote monitoring

[0097] Throughout the entire operation, all operating parameters, including real-time and historical concentration data from each ion concentration sensor 16, as well as the output voltage, current, and power curves of the power module, and event logs for each mode switch, are automatically and continuously recorded and stored by the data analysis and processing terminal 13. Authorized managers can access this data and assess the system status at any time via a remote monitoring terminal (such as an office computer or mobile device) with a graphical interface, without needing to be physically present on-site. This truly achieves unattended intelligent management of the entire barrier system.

[0098] Step 5: Long-term monitoring and system maintenance

[0099] The barrier system of this invention is designed for long-term, stable service. Therefore, in addition to routine intelligent control and operation, it includes a complete set of procedures for long-term effectiveness verification and maintenance of key components to ensure its effectiveness throughout its entire life cycle. Steps 3 and 4 are continuously performed to evaluate the interception effect of the electric geobarrier by regularly sampling and monitoring the protected water body 14 downstream of the electric geobarrier, and to periodically inspect or replace the reactive material in the permeable reactive wall 18.

[0100] (1) Verification of final results

[0101] Although the intelligent control system can provide continuous process monitoring data, periodic effectiveness verification is necessary to ultimately evaluate the macroscopic interception performance of the barrier system and meet environmental regulatory compliance requirements. Specifically, sampling points are set up quarterly at the upstream, midstream, and downstream sections of the protected water body 14 downstream of the barrier, and sampling is conducted in accordance with national environmental monitoring standards. Samples are sent to a certified third-party laboratory for precise analysis using standard methods such as atomic absorption spectrometry (AAS). The obtained quarterly water quality analysis reports are compared with the established protection target (Class III water quality standard in the "Surface Water Environmental Quality Standard" GB 3838-2002) to serve as the final basis for evaluating and verifying the overall performance of the barrier system.

[0102] (2) Performance evaluation and maintenance

[0103] When the system predicts or detects a significant decrease in the activity of the Permeable Reactive Barrier 18 (PRB) material, a maintenance procedure can be initiated. A conduit system for maintenance is pre-embedded in the PRB area of ​​the cathode row 6. During maintenance, regeneration agents (e.g., dilute acid solution for zero-valent iron passivation) can be injected into the PRB area through this conduit system for in-situ chemical regeneration. This allows for rapid restoration of its contaminant treatment capacity in a low-cost, excavation-free manner, ensuring the long-term sustainable operation of the entire barrier system.

[0104] The foregoing description is not intended to limit the invention, nor is the invention limited to the examples given. Any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the invention should also be considered within the protection scope of the invention.

Claims

1. A smart-controlled electric geotechnical barrier system, characterized in that: The device includes an electric geotechnical barrier device and an intelligent control device. The electric geotechnical barrier device includes a vertically arranged and parallel cathode row and an anode row, with the cathode row located upstream of the anode row. The cathode array includes at least two cathode electrode plates and a plurality of equally spaced cathode conductive cores encased within the cathode electrode plates. The gaps between two adjacent cathode electrode plates are filled with a permeable reactive wall. The anode array includes at least two anode electrode plates and a plurality of equally spaced anode conductive cores encased within the anode electrode plates. The gaps between two adjacent anode electrode plates are filled with anode backfill soil. The intelligent control device includes a power supply module and a monitoring and control module. The positive output terminal of the power supply module is electrically connected to the anode conductive core, and the negative output terminal of the power supply module is electrically connected to the cathode conductive core. The monitoring and control module is used to collect and analyze the heavy metal ion concentration in the anode row region in real time and send control commands to the power supply module. The power supply module adjusts the electric field strength applied between the anode row and the cathode row according to the control commands. The monitoring and control module includes an ion concentration sensor and a data analysis and processing terminal. The ion concentration sensor is arranged in a three-dimensional array on the anode row. The ion concentration sensor collects heavy metal ion concentration data at different depths and positions of the anode in real time and transmits it to the data analysis and processing terminal. The data analysis and processing terminal receives and analyzes the heavy metal ion concentration data, compares the maximum heavy metal ion concentration with a preset threshold, and generates control commands based on the analysis results to adjust the current of the power module in real time. The data analysis and processing terminal compares the received real-time heavy metal ion concentration data with preset upper and lower thresholds. When the maximum heavy metal ion concentration is higher than the upper threshold, it sends a command to the power module to increase the output power and enhance the electric field strength. When the maximum heavy metal ion concentration remains below the lower threshold, a command is sent to the power module to reduce the output power or enter a low-power maintenance mode; if the heavy metal ion concentration is between the upper and lower thresholds, the current output power is maintained unchanged.

2. The intelligent control electric geotechnical barrier system according to claim 1, characterized in that: Both the cathode electrode plate and the anode electrode plate are provided with multiple reinforcing ribs extending along their two sides.

3. The intelligent control electric geotechnical barrier system according to claim 1, characterized in that: Both the anode conductive core and the cathode conductive core are composed of at least one of a conductive polymer, a carbon fiber mesh, or an inert metal mesh.

4. The intelligent control electric geotechnical barrier system according to claim 1, characterized in that: The ion concentration sensor includes at least three monitoring points along the vertical direction of the anode row: a top sensor located near the groundwater level, a middle sensor located at the core depth of pollutant transport, and a bottom sensor located at the bottom of the aquifer near the impermeable bedrock. Several ion concentration sensors are evenly distributed along the horizontal direction of the anode row.

5. The intelligent control electric geotechnical barrier system according to claim 1, characterized in that: The power module includes an adjustable DC power supply, a fuse for circuit overload protection, and an ammeter for monitoring the current in the circuit. The fuse and the ammeter are connected in series in the power supply circuit.

6. A method for operating an intelligently controlled electric geotechnical barrier system, characterized in that... The electric geobarrier system according to any one of claims 1-5 includes the following steps: Step 1, Site Construction: In the underground aquifer of a heavy metal contaminated site, vertical cathode and anode rows are deployed in the downstream area of ​​the heavy metal pollutant migration zone, wherein the cathode rows are deployed on the upstream side of the anode rows to define the electrodynamic geotechnical barrier zone, and a permeable reactive wall is constructed in the gaps between the cathode rows. Step 2, System Connection and Initialization: Connect the cathode and anode blocks to the power module respectively, complete the signal connection between the ion concentration sensor and the data analysis and processing terminal, perform system initialization, and set the initial operating parameters of the power module and the upper and lower limit thresholds of the pollutant concentration; Step 3, Active Interception and In-situ Remediation: Activate the power module to establish a DC electric field between the cathode and anode rows. The migration of the pollution plume is blocked by electroosmotic flow, and charged heavy metal ions are enriched in the cathode row area through the electromigration effect, and then adsorbed or degraded in-situ through the permeable reactive wall. Step 4, Intelligent Control: While Step 3 is being performed, the concentration of heavy metal ions in the anode row area is collected by the ion concentration sensor. The data analysis and processing terminal receives the data and compares the maximum collected heavy metal ion concentration with the preset upper and lower thresholds of the ion concentration. A control command is generated and sent to the power module to dynamically adjust the intensity of the DC electric field. Step 5, System Maintenance: Continue to execute steps 3 and 4, regularly sample and monitor the protected water body downstream of the electro-hydroelectric barrier to evaluate the interception effect of the electro-hydroelectric barrier, and regularly inspect or replace the reactive material in the permeable reactive wall.

Images