A contaminated site remediation system

Abstract

The utility model discloses a kind of pollution site remediation systems, including control terminal, vertical barrier subsystem, permeable reaction wall subsystem and hydraulic cycle subsystem, vertical barrier subsystem includes vertical barrier wall, permeation monitor and water quality monitor I;Permeable reaction wall subsystem includes permeable reaction wall and water quality monitor II, vertical barrier wall lower end and barrier wing wall lower end are set in aquiclude;Permeable reaction wall is set between two barrier wing walls, and its two ends are respectively sealed with two barrier wing walls Connection;Water circulation subsystem includes regulation and control subsystem and water quality monitor III, regulation and control subsystem includes pumping well, injection well and recharge equipment;Control terminal is adjusted to the flow of pumping well and injection well according to monitoring data.The utility model integrates "barrier-reaction-cycle" trinity design, uses the hydraulic cycle of pumping well, recharge equipment and injection well, dynamically optimizes flow field, and pollutant removal rate is improved to more than 95%.

Description

Technical Field

[0001] This utility model relates to the field of contaminated site remediation and risk management technology. More specifically, it relates to a contaminated site remediation system, which is suitable for the treatment of sites contaminated with heavy metals, organic pollutants and compound pollutants, and can be widely used in high-risk areas such as chemical contaminated sites, mine tailings ponds and oil spill areas. Background Technology

[0002] With rapid industrialization and urbanization, numerous industrial sites, mines, gas stations, and chemical enterprises have suffered from soil and groundwater pollution due to historical issues or unforeseen accidents, seriously threatening the ecological environment and human health. Because pollutants are highly toxic, persistent, and mobile, if not effectively controlled, they may spread through groundwater to the surrounding environment and even enter drinking water sources, causing long-term ecological risks.

[0003] Currently, contaminated site remediation technologies are mainly classified into four categories: physical barrier, chemical remediation, bioremediation, and combined remediation. Among them, vertical barrier technologies (such as cement-bentonite walls, sheet piles, and HDPE membranes) block pollutant migration by constructing low-permeability barriers underground, and are suitable for sites with clearly defined pollution sources that require rapid control of diffusion. However, they have drawbacks such as only blocking without degradation and dependence on geological conditions. Permeable reactive walls (PRBs) achieve in-situ degradation of pollutants by filling them with active materials, but they rely on natural hydraulic gradients and face challenges such as low remediation efficiency in low-permeability sites and poor applicability to heterogeneous sites. Hydraulic circulation technologies (such as pumping well systems) remove pollutants by extracting contaminated groundwater and performing surface treatment. They are suitable for rapidly reducing pollution or treating small- to medium-sized pollution plumes, but they suffer from high energy consumption, the potential for long-term pumping to alter the groundwater flow field, the possibility of rebound after pumping stops, and limited adaptability to complex geological conditions.

[0004] While existing combined remediation technologies attempt to integrate vertical barriers with permeable reactive barriers (PRBs) or hydraulic circulation, they still suffer from shortcomings such as insufficient synergy, lack of intelligent control, and poor long-term stability. Specifically, these shortcomings manifest as: insufficient understanding of the site's hydrogeological conditions; irrational layout of PRBs and barriers; simplistic overlay of technologies lacking overall coherence and systematic approach; and improper operation leading to pollutant escape. Furthermore, reliance on manual monitoring makes it difficult to respond promptly to changes in pollutant concentrations or hydrological conditions. Utility Model Content

[0005] To address the aforementioned technical problems in existing technologies, this utility model provides a contaminated site remediation system. This system employs vertical barriers, permeable reactive walls, and hydraulic circulation to couple contaminated sites, and combines real-time monitoring data to achieve intelligent control. It is an efficient, economical, and sustainable comprehensive contaminated site management system, thereby solving the key technical bottlenecks and practical application problems existing in current contaminated site remediation technologies.

[0006] The present invention adopts the following technical solution:

[0007] The system includes a control terminal and a vertical barrier subsystem, a permeable reactive wall subsystem, and a hydraulic circulation subsystem electrically connected to the control terminal. The vertical barrier subsystem includes a vertical barrier wall, a permeability monitor installed along the vertical barrier wall, and a water quality monitor I for online monitoring of water pollution inside and outside the vertical barrier wall. The permeable reactive wall subsystem includes a permeable reactive wall and a water quality monitor II, which is used for online monitoring of groundwater quality changes inside the permeable reactive wall. The vertical barrier wall surrounds the contaminated site from upstream to downstream, extending to the downstream side of the contaminated site to form two barrier wing walls. The lower ends of the vertical barrier wall and the lower ends of the barrier wing walls are both located in a waterproof layer. The permeable reactive wall is located between the two barrier wing walls, and its two ends are respectively sealed to the two barrier wing walls.

[0008] The water cycle subsystem includes a control subsystem and a water quality monitor III. The control subsystem includes pumping wells, injection wells, and reinjection equipment. Several injection wells are distributed within the contaminated site. The injection wells are connected to the reinjection equipment via injection pipelines. At least one row of pumping wells is provided in the area outside the contaminated site, which is enclosed by the two barrier wing walls and the permeable reactive wall. The pumping wells are connected to the reinjection equipment via pumping pipelines. The water quality monitor III is used to monitor the water pollution status in the pumping well area online.

[0009] The control terminal is electrically connected to the infiltration monitor, water quality monitor I, water quality monitor II, and water quality monitor III, respectively. Based on the monitoring data, the control terminal commands the hydraulic circulation subsystem to adjust the flow rate of the pumping well and the injection well.

[0010] Furthermore, the hydraulic circulation subsystem also includes a chemical injection subsystem, which utilizes the injection wells to perform in-situ chemical oxidation or bioremediation of high-concentration pollutants present in the contaminated site. Preferably, the barrier wing walls extend downstream for 15-20m, the spacing between the barrier wing walls is 20-50m, and the wall body is embedded with a waterproof layer of at least 1.5m, which is a modified bentonite-cement composite wall with a permeability coefficient ≤1×10⁻⁶. -7 cm / s.

[0011] More preferably, a variable frequency submersible pump is installed in the pumping well, the outlet of the variable frequency submersible pump is connected to the reinjection equipment, and the control subsystem is electrically connected to the variable frequency submersible pump to actively control the groundwater flow rate in the contaminated site to be consistent with the infiltration rate of the permeable reactive barrier.

[0012] Preferably, the permeable reactive wall is filled with a chemical material, the lower end of which is located on the top surface of the waterproof layer. The porosity of the chemical material is 35-40%, and the permeability coefficient is 10. -3 -10 -4 The flow rate is cm / s, the wall thickness is 1.5-3.5m, and the water flow rate is 0.5-2.0m. 3 / (m 2 ·d).

[0013] Compared with traditional technologies, this utility model has the following technical advantages and application effects:

[0014] A. In this utility model system, a vertical barrier wall and a permeable reactive wall surround the contaminated site from upstream to downstream, and several injection wells are set in the contaminated site. The permeable reactive wall and pumping wells are set between the two barrier wing walls formed by the downstream extension of the vertical barrier wall. The system integrates the "barrier-reaction-circulation" three-in-one design, realizing the deep coupling of each part. The vertical barrier wall provides a stable reaction environment for the permeable reactive wall (PRB), and the permeable reactive wall (PRB) ensures the in-situ degradation of pollutants. The hydraulic circulation formed by the pumping wells, reinjection equipment and injection wells, combined with the dynamic optimization of the flow field by the pumping and injection well group, the three work together to increase the pollutant removal rate to more than 95%.

[0015] B. The vertical barrier wall in this utility model adopts a modified bentonite-cement composite wall, and is combined with a leakage monitor installed along the vertical barrier wall for online monitoring of leakage, achieving a pollutant diffusion blocking rate of ≥99.9%, which is especially suitable for highly permeable strata or areas with developed fissures, and improves the seepage prevention performance by more than 50% compared with conventional barrier technology.

[0016] C. The system is equipped with a control subsystem. Combining the upstream, contaminated site, and downstream water pollution information collected by various monitors, the control subsystem dynamically optimizes the pumping and injection parameters by adjusting the flow rates of the pumping and injection wells, thereby controlling the flow rate at the contaminated site. It can accurately locate and quickly respond to high-pollution points in the contaminated site by activating the chemical injection system to inject oxidants into the injection wells corresponding to high-concentration pollution areas, so that pollutants can be rapidly degraded.

[0017] D. This utility model system actively regulates the groundwater flow rate (0.3-0.8m / d) through hydraulic circulation and works synergistically with the permeable reactive barrier (PRB), which improves the pollutant migration efficiency by 3-5 times and shortens the remediation cycle to 5-10 years. It is especially suitable for low-permeability sites or high-concentration pollution areas.

[0018] E. This invention fills the permeable reactive wall with a material that can adsorb and degrade intermediate products, and adopts a closed-loop hydraulic circulation control to avoid the leakage of pollutants, making the risk of secondary pollution controllable. Compared with traditional extraction treatment technology, it reduces the amount of sludge / waste gas generated by more than 80%.

[0019] F. The energy consumption and operating costs generated by this utility model system are significantly reduced. It adopts a combination of variable frequency submersible pump and control subsystem for flow control, which reduces hydraulic circulation energy consumption by 40-50%. The permeable reactive wall material adopts corrosion-resistant and highly active materials, which extends the service life and reduces the overall operation and maintenance cost by more than 40%. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of this utility model, the drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the system architecture provided by this utility model;

[0022] Figure 2 This is a schematic diagram of the system layout provided by this utility model;

[0023] Figure 3 yes Figure 1 The system cross-sectional structure diagram shown is shown below.

[0024] The diagram is labeled as follows:

[0025] 1-Vertical barrier wall; 2-Permeable reactive wall; 3-Barrier wing wall; 4-Contaminated site

[0026] 5-Injection well; 6-Pumping well; 7-Reinjection equipment; 8-Chemical injection subsystem; 9-Injection pipeline

[0027] 10 - Impermeable layer; 20 - Pumping pipeline. Detailed Implementation

[0028] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0029] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] like Figures 1 to 3 As shown, this utility model provides a contaminated site remediation system, including a control terminal and a vertical barrier subsystem, a permeable reactive wall subsystem, and a hydraulic circulation subsystem electrically connected to the control terminal. The vertical barrier subsystem includes a vertical barrier wall 1, a permeability monitor installed along the vertical barrier wall 1, and a water quality monitor I that monitors the water pollution inside and outside the vertical barrier wall 1 online. The water quality monitor I monitors the changes in groundwater and pollutant concentrations upstream and inside the contaminated site 4 online, and transmits the obtained monitoring data to the control terminal in real time. The permeability monitor can perform online permeability monitoring of the vertical barrier wall, ensuring the physical barrier effect of the vertical barrier wall. By continuously reducing pollutants, it reduces the impact of high-concentration pollutants on the vertical barrier wall or causes it to penetrate the wall, creating favorable conditions for subsequent degradation treatment. The permeable reactive wall subsystem includes a permeable reactive wall 2 and a water quality monitor II. The water quality monitor II is used to monitor the changes in groundwater quality inside the permeable reactive wall 2 online and transmits the monitoring data to the control terminal in real time.

[0032] The hydraulic retention time is determined based on the pollutant degradation half-life, generally 12-24 hours. The design life of the permeable reactive barrier is 5-10 years, including one reagent replenishment cycle. It is preferable to fill the permeable reactive barrier with reagent materials. The filling reagents can be determined according to the type of pollutant. Taking organic pollution as an example, the core reactive agents are mainly: zero-valent iron (ZVI), accounting for 60-70%; activated carbon, accounting for 20-30%; slow-release materials, accounting for 10%; and auxiliary additives. For example... Figure 2As shown, the lower end of the permeable reactive wall is located on the top surface of the underground impermeable layer 10. The porosity of the filling agent material is 35-40%, and the permeability coefficient is 10. -3 -10 -4 The flow rate is cm / s, two orders of magnitude greater than the surrounding strata; the wall thickness is 1.5-3.5m; and the water flow rate is 0.5-2.0m. 3 / (m 2 •d) can be adjusted according to the groundwater flow rate.

[0033] A vertical barrier wall 1 surrounds the contaminated site 4 from upstream to downstream, extending downstream to form two barrier wing walls 3. The lower ends of both the vertical barrier wall 1 and the barrier wing walls 3 are embedded in the impermeable layer 10. A permeable reactive wall 2 is positioned between the two barrier wing walls 3, with its ends sealed to both wing walls 3. The extension length of the barrier wing walls 3 is 15-20m, and the spacing between them is 20-50m. The vertical barrier wall 1 is constructed of modified bentonite-cement composite material with a permeability coefficient ≤1×10⁻⁶. -7 The wall thickness is ≥1.5m with an embedded waterproof layer and a compressive strength ≥30MPa. Leakage monitoring devices, consisting of distributed optical fibers and sensors, are installed along the wall to monitor changes in the wall's barrier performance. In the modified bentonite-cement composite wall, cement accounts for 15-30% of the mixture, and bentonite slurry accounts for 70-85% of the mixture, with bentonite accounting for 5%-10% of the bentonite slurry.

[0034] The water circulation subsystem includes a control subsystem and a water quality monitor III. The control subsystem includes pumping wells 6, injection wells 5, and reinjection equipment 7. Several injection wells 5 are distributed within the contaminated site 4, with a spacing of 20-30m between them, which can cover the entire contaminated site 4. The injection wells 5 can be controlled according to the local contamination situation of the contaminated site 4. The injection wells 5 are connected to the reinjection equipment 7 through injection pipelines 9. At least one row of pumping wells 6 is provided in the area outside the contaminated site 4, which is enclosed by two barrier wing walls 3 and a permeable reactive wall 2. The pumping wells 6 are connected to the reinjection equipment 7 through pumping pipelines 20. The water quality monitor III is used to monitor the water quality in the downstream area where the pumping wells 6 are located online and transmit the data to the control terminal. Further optimization involves using a variable frequency submersible pump to extract water from the pumping well 6 and then pumping it into the reinjection equipment 7 via the pumping pipeline 20. Through numerical simulation and analysis of monitoring data at the control terminal, the reinjection equipment 7 is controlled to inject water into the required injection well 5, while also controlling the flow rate of water injection and pumping.

[0035] This invention activates the pumping / injection well group and initiates the hydraulic circulation subsystem, optimizing the flow field to maintain a flow velocity of 0.3-0.8 m / d, while simultaneously monitoring changes in pollutant concentration in the pumping / injection area. Water quality monitor II allows real-time monitoring of the consumption of reactive material within the permeable reactive barrier, enabling timely detection and maintenance. Water quality monitors I, II, and III monitor target pollutant indicators in the groundwater upstream, downstream, and inside and outside the vertical barrier, analyzing pollutant removal efficiency and simulating real-time pollution diffusion. Based on the monitoring data, the operation plan for the pumping / injection wells is continuously adjusted, reactive material is replenished (when the removal rate is <80%), and the normal operation of the barrier system is maintained.

[0036] This invention arranges one or more rows of pumping wells behind the permeable reactive wall. The pumped groundwater should meet the remediation requirements. After the groundwater is pumped out, it is injected into the target remediation area through reinjection equipment and injection wells. The pumping wells can also serve as emergency wells to deal with the spread of groundwater contamination exceeding the standard.

[0037] As a further preferred embodiment of this utility model, the hydraulic circulation subsystem also includes a chemical injection subsystem, which utilizes injection wells to perform in-situ chemical oxidation or bioremediation of high-concentration pollutants present in the contaminated site. The target remediation area is flushed through reinjection equipment and injection wells, while the chemical injection subsystem, integrated with the injection wells, performs in-situ chemical oxidation or bioremediation on any potential high-concentration pollutants. Furthermore, water quality monitors I, II, and III provide real-time online monitoring of the pumping area and the injection and chemical injection areas, monitoring changes in groundwater and pollutant concentrations and transmitting the data to the control terminal.

[0038] A chemical injection subsystem is set up in conjunction with the water injection wells on site. Reaction agents are injected according to the type of pollutants to degrade or release them (organic pollutants are oxidized and degraded, and heavy metal pollutants are released into the washing liquid); the emergency circulation mode of the hydraulic circulation subsystem is activated to control the downstream diffusion of pollutants.

[0039] This invention optimizes the hydraulic circulation mode (such as intermittent operation), combines in-situ chemical oxidation / bioremediation technologies, and utilizes a chemical injection subsystem to reduce the source of high-concentration pollutants or promote the continuous release of pollutants trapped in the soil into the groundwater. This eliminates the need for periodic replacement of the filler reaction material in the permeable reactive barrier, reducing system operating costs by more than 40%.

[0040] The control terminal is electrically connected to the infiltration monitor, water quality monitor I, water quality monitor II, and water quality monitor III, respectively. The control terminal itself can be equipped with a simulation module to obtain changes in pollutant concentration at the contaminated site based on numerical simulation and real-time monitoring. It then instructs the hydraulic circulation subsystem to regulate the flow rates of the pumping and injection wells, maintaining the stability of the groundwater flow field and controlling the spread of contaminants. Simultaneously, the installation of a variable frequency submersible pump enables efficient system operation. By monitoring the effectiveness of the permeable reactive barrier filling material and changes in groundwater quality, the system ensures the stable and efficient removal of pollutants from the groundwater by the filling material.

[0041] This invention utilizes Medflow software to numerically simulate pollutant concentrations based on data from inside and outside the barrier wall, inside the PRB, and downstream. It simulates pollutant concentration changes, predicts pollution plume trends, and identifies areas exceeding limits. The concentration of pollutants in groundwater after passing through the permeable reactive barrier should not exceed the risk control value. Simultaneously, a maximum concentration limit for groundwater pollutants within the barrier wall is set (which can be 5-100 times the risk control value). Based on numerical simulations and real-time monitoring data, the system ensures normal operation of the site remediation system, continuously eliminating pollutants within the site. When the pollutant concentration behind the barrier wall exceeds the risk control value, emergency measures such as extraction are implemented. When the pollutant concentration inside the barrier wall exceeds the maximum concentration limit, measures such as injecting chemicals are taken to reduce the excess. When the pollutant concentration behind the permeable reactive barrier exceeds the risk control value, pumping wells should be activated for emergency extraction or operated simultaneously with the chemical injection system to control pollution spread.

[0042] The aforementioned seepage monitor is the Puqi PQ-227A dike seepage detector manufactured by Hunan Puqi Water Environment Research Institute; Water quality monitor I, Water quality monitor II, and Water quality monitor III are INTAI-PRO manufactured by Sente Soil Remediation Research Institute (Shenzhen) Co., Ltd.

[0043] The contaminated site remediation system based on the coupling of "vertical barrier, permeable reactive barrier (PRB), and hydraulic circulation" of this utility model integrates the "barrier-reaction-circulation" three-in-one design to achieve deep coupling of subsystems: the vertical barrier provides a stable reaction environment for the permeable reactive barrier (PRB), the permeable reactive barrier (PRB) ensures the in-situ degradation of pollutants, and the hydraulic circulation dynamically optimizes the flow field through a group of injection wells. The three work together to increase the pollutant removal rate to over 95%. The permeable reactive barrier (PRB) is existing technology and will not be described in detail here.

[0044] Under the control of the terminal, the hydraulic circulation subsystem actively regulates the synergistic effect of groundwater flow velocity (0.3-0.8 m / d) and the permeable reactive barrier (PRB). Specifically, the vertical barrier subsystem creates a stable reaction environment for the PRB subsystem; the PRB subsystem ensures the complete remediation and degradation of pollutants; and the hydraulic circulation subsystem ensures the efficient transport of pollutants and the continuous function of the reaction zone. The pollutant migration efficiency is increased by 3-5 times, and the remediation cycle is shortened to 5-10 years. It is especially suitable for low-permeability sites or high-concentration polluted areas, and the pollutant degradation rate and remediation cycle are optimized.

[0045] The remediation system provided by this invention can also address the problem of uneven flow field in traditional technologies by flexibly arranging multiple rows of injection and extraction wells and vertical barrier wall gaps (20-50m) for heterogeneous aquifers. It is applicable to over 90% of contaminated site types, including chemical plants, mines, and oil spill sites. Furthermore, the vertical barrier walls, permeable reactive walls, and barrier wing walls can be integrated with water quality monitors and permeability monitors. The modular design, tailored to different contamination types including heavy metals, organic matter, or complex contamination, and with a formation permeability of 10... -4 ~10 -6 This invention is applicable across a range of cm / s. The remediation system can achieve a comprehensive goal of increasing contaminated site remediation efficiency by over 50%, reducing operating costs by 40%, and extending system lifespan to 10 years, providing a green and efficient solution for contaminated site remediation.

[0046] To address the problems of material aging and active component failure in conventional permeable reactive barrier (PRB) remediation systems, this invention employs a corrosion-resistant composite material to construct a barrier system and develops a long-lasting, slow-release reactive material for the PRB. This slow-release reactive material, using paraffin as a carrier and persulfate as an oxidant, can remove 70-90% of organic pollutants such as halogenated hydrocarbons. Combined with an injection system installed in the contaminated area, in-situ chemical oxidation or bioremediation is used to reduce the impact of short-term high-concentration pollutants on the PRB. Furthermore, an intelligent monitoring system is used to evaluate the system's operating status in real time, enabling preventative maintenance and ensuring stable operation for more than 10 years.

[0047] Any aspects not described herein are applicable to existing technologies.

[0048] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this utility model.

Claims

1. A contaminated site remediation system, characterized in that, The system includes a control terminal and a vertical barrier subsystem, a permeable reactive wall subsystem, and a hydraulic circulation subsystem electrically connected to the control terminal. The vertical barrier subsystem includes a vertical barrier wall, a permeability monitor installed along the vertical barrier wall, and a water quality monitor I for online monitoring of water pollution inside and outside the vertical barrier wall. The permeable reactive wall subsystem includes a permeable reactive wall and a water quality monitor II, which is used for online monitoring of groundwater quality changes inside the permeable reactive wall. The vertical barrier wall surrounds the contaminated site from upstream to downstream, extending to the downstream side of the contaminated site to form two barrier wing walls. The lower ends of the vertical barrier wall and the lower ends of the barrier wing walls are both located in a waterproof layer. The permeable reactive wall is located between the two barrier wing walls, and its two ends are respectively sealed to the two barrier wing walls. The hydraulic circulation subsystem includes a control subsystem and a water quality monitor III. The control subsystem includes pumping wells, injection wells, and reinjection equipment. Several injection wells are distributed within the contaminated site. The injection wells are connected to the reinjection equipment via injection pipelines. At least one row of pumping wells is provided in the area outside the contaminated site, enclosed by the two barrier wing walls and the permeable reactive wall. The pumping wells are connected to the reinjection equipment via pumping pipelines. The water quality monitor III is used to monitor the water pollution status in the pumping well area online. The control terminal is electrically connected to the infiltration monitor, water quality monitor I, water quality monitor II, and water quality monitor III, respectively. Based on the monitoring data, the control terminal commands the hydraulic circulation subsystem to adjust the flow rate of the pumping well and the injection well.

2. The contaminated site remediation system according to claim 1, characterized in that, The hydraulic circulation subsystem also includes a chemical injection subsystem, which uses the injection well to perform in-situ chemical oxidation or bioremediation of high-concentration pollutants in the contaminated site.

3. The contaminated site remediation system according to claim 1, characterized in that, The barrier wing walls extend downstream for 15-20m in length, with a spacing of 20-50m between them. Each wing wall is embedded at least 1.5m into a waterproof layer, which is a modified bentonite-cement composite wall with a permeability coefficient ≤1×10⁻⁶. -7 cm / s.

4. The contaminated site remediation system according to claim 1, characterized in that, A variable frequency submersible pump is installed in the pumping well. The outlet of the variable frequency submersible pump is connected to the reinjection equipment. The control subsystem is electrically connected to the variable frequency submersible pump and actively controls the groundwater flow rate in the contaminated site to be consistent with the infiltration rate of the permeable reactive barrier.

5. The contaminated site remediation system according to claim 1, characterized in that, The permeable reactive wall is filled with a chemical material, the lower end of which is located on the top surface of the waterproof layer. The porosity of the chemical material is 35-40%, and the permeability coefficient is 10. -3 -10 -4 The flow rate is cm / s, the wall thickness is 1.5-3.5m, and the water flow rate is 0.5-2.0m. 3 / (m 2 ·d).

Images