A groundwater organic pollution remediation system and method

Abstract

This invention relates to the field of groundwater pollution remediation technology, and discloses a groundwater organic pollution remediation system and method. The method includes: extracting organically polluted groundwater through an extraction module to create negative pressure, causing pollutants to accumulate and immobilize on an adsorption module; expanding the cultivation of native bacteria in the organically polluted groundwater extracted by the extraction module through a microbial culture module; injecting the cultured organically polluted groundwater containing bacteria into a biocontrol well to form a biodegradation barrier; and optionally, when the groundwater flow rate is too fast to ensure that pollutants are controlled within the pollution plume range, pumping water through a hydraulic replenishment control module to control the groundwater flow field and control the organic pollutants within the pollution plume range. The groundwater organic pollution remediation system and method according to this invention can effectively remove pollutants and form an effective biodegradation barrier.

Description

Technical Field

[0001] This invention relates to the field of groundwater pollution remediation technology, specifically to a groundwater organic pollution remediation system and method. Background Technology

[0002] With the increasing emphasis placed on soil and groundwater by the state, multiple rounds of surveys on soil and groundwater pollution have been conducted. Organic pollution of groundwater from oil and petrochemical enterprises is widespread. Furthermore, because groundwater pollution is often difficult to detect, it easily migrates with water after entering aquifers, affecting a wide area and potentially causing adverse social impacts. Therefore, controlling and remediating pollution is crucial.

[0003] Currently, there are many technologies for controlling and remediating organic pollution in groundwater, including aeration, chemical oxidation, bioremediation, and hydraulic control. However, each technology has its specific application environment. For example, aeration is suitable for areas with high concentrations of organic pollutants, while bioremediation is often suitable for non-emergency pollution situations, where time can replace cost, achieving green and environmentally friendly remediation, and where pollutant concentrations are generally low. Therefore, for a complete pollution plume, there are high, medium, and low concentration zones, and a single technology cannot effectively control and remediate it; multiple technologies need to be organically combined to form a complete remediation system. Furthermore, soil and groundwater remediation often requires the construction of underground engineering projects, causing significant site disturbance, posing too great a safety risk for some operating enterprises, and the cost is often high. Generally, the more cost-effective biological methods can only be injected in stages, and there are also problems such as poor adaptability of the strains and short duration of effect, which can easily lead to unsatisfactory remediation results.

[0004] Currently, there are numerous patents related to the remediation and management of organic pollution in groundwater, including the preparation of bioremediation materials such as slow-release oxygen (e.g., patent application CN102491497B), the preparation of functional microbial communities (e.g., patent application CN109665633A), the setting of injection wells (e.g., patent application CN205032471U), automated remediation and early warning integrated devices, and in-situ remediation methods (e.g., patent application CN108655160B). Among in-situ remediation methods, there are many optimizations and improvements to single technologies. For example, patent application CN102249428B proposes remediation of oil-contaminated groundwater using simple biodegradation by setting the location of nutrient injection wells and monitoring wells; patent application CN109279672A proposes a multi-stage permeable reactive barrier, improving its effectiveness through optimized barrier structure; and patent application CN112744930A provides optimization of the injection effect of industrial syrup through the layout of injection points. Many patents also combine multiple technologies. For example, patent application CN113479955A proposes combining in-situ chemical remediation with ex-situ extraction remediation. The remediation agent is added to the contaminated area and can interact with the difficult-to-extract solid medium, avoiding the "tailing" effect that occurs in groundwater extraction technology. Patent application CN216614348U discloses a remediation system for acidic groundwater in abandoned pyrite mine areas, including a mine wastewater collection unit, a slag wastewater collection unit, a natural aeration unit, a neutralization reaction unit, a sedimentation unit, and an artificial wetland unit, combining aeration and the biological action of artificial wetlands. However, none of the above technologies have conducted specific analysis on contaminated areas with different concentrations within a complete pollution plume, and there are few remediation systems that integrate adsorption-biodegradation-hydraulic control. Furthermore, the biodegradation part involved is injected in stages, which cannot effectively address the poor adaptability of the bacterial strains, their inability to reproduce effectively, and the inability to guarantee the effective time. In addition, the preparation environment of the biological agent is not integrated with the injection, requiring long-distance transportation and resulting in poor continuity.

[0005] In summary, while existing patents primarily address the remediation of organically polluted groundwater, few focus on zone-specific remediation of intact pollution plumes. Furthermore, the added agents are not integrated with the injection site, hindering the continuous enhancement and replenishment of biodegradation, potentially leading to diminished effectiveness. Some methods also require extensive engineering construction, severely impacting safe production. Therefore, a method is needed to address organic pollution with minimal disturbance, environmental friendliness, and sustained effective biological action, ensuring pollution control within effective limits and guaranteeing effective remediation. Summary of the Invention

[0006] The purpose of this invention is to address the common problem of organic groundwater pollution in oil and petrochemical enterprises by providing a groundwater organic pollution remediation system and method, particularly suitable for high-permeability areas. The technical solution of this invention allows for targeted remediation of different areas of the pollution plume, reducing extensive engineering construction. It uses biological methods instead of interception ditches to form a pollution barrier, preventing downstream spread of pollution. In areas with medium to high pollution levels, replaceable adsorption modules are used, and the flow direction is adjusted during the extraction process to adsorb pollutants. A portion is extracted and fed into a microbial culture module. The resulting contaminated groundwater carrying microorganisms is then reinjected into a biocontrol well to form a biodegradation barrier. Hydraulic control replenishment wells are established in the upstream high-concentration areas of the pollution plume, and extraction is performed as needed to ensure the circulation of pollutants within the remediation system. The entire remediation method is based on groundwater wells, does not involve large-scale underground engineering, and integrates the cultivation, expansion, and injection of biological microorganisms, achieving continuous injection and effectively ensuring the abundance of underground microorganisms and the effectiveness of biological action. This method is suitable for organically contaminated sites in high-permeability areas and has good remediation effects.

[0007] Specifically, the present invention provides a groundwater organic pollution remediation system, comprising:

[0008] The adsorption module is placed in a groundwater well in the middle to upper reaches of the pollution plume;

[0009] An extraction module, connected to the adsorption module, is used to extract organic pollutants from groundwater to create negative pressure, causing pollutants to accumulate and be fixed in the adsorption module.

[0010] The microbial culture module is used to expand the culture of native microbial strains in organic-contaminated groundwater extracted by the extraction module.

[0011] A biocontrol module includes an injection device and a biocontrol well, wherein the biocontrol well is located downstream of the contamination plume, and the injection device is used to inject organic contaminated groundwater containing bacteria, which has been cultured in the bacterial culture module, into the biocontrol well.

[0012] The hydraulic replenishment control module is located upstream of the pollution plume. Based on the groundwater flow velocity, it determines whether it is necessary to use the hydraulic replenishment control module to pump water upstream of the pollution plume in order to control the organic pollutants within the range of the pollution plume.

[0013] Preferably, the adsorption module includes a porous frame and an adsorption material filled within the porous frame.

[0014] Preferably, the adsorbent material is zeolite and / or hard activated carbon with a particle size of not less than 2 mm.

[0015] Preferably, the porous frame is cylindrical and made of PVC.

[0016] Preferably, the extraction module includes an extraction pipe, a pollutant detection device, and an extraction pump. The inlet end of the extraction pipe is connected to the adsorption module, and the outlet end is connected to the microbial culture module. The pollutant detection device is used to detect the flow rate and pollutant content of the extracted organic pollutants in the groundwater.

[0017] Preferably, the extraction pump uses an intermittent lifting method.

[0018] Preferably, the extraction pump is a solar-powered pump.

[0019] Preferably, a leak-proof mesh is provided at the inlet of the extraction pipe.

[0020] Preferably, the microbial culture module includes a culture tank, an adjustment device, and a pollutant and microbial abundance detection device. The inlet of the culture tank is connected to the extraction module. The adjustment device is used to control the addition of nutrients and adjust the water volume. The pollutant and microbial abundance detection device is used to detect the concentration of pollutants, the content and activity of microorganisms in the culture tank, and to guide the operation of the adjustment device based on the detection results.

[0021] Preferably, the biocontrol module includes at least three biocontrol wells.

[0022] Preferably, the hydraulic replenishment control module includes one or more hydraulic replenishment control wells. When the groundwater flow rate is too fast and it is impossible to ensure that the pollutants are controlled within the range of the pollution plume, water is pumped through the hydraulic replenishment control well upstream of the pollution plume to control the flow field of the groundwater and control the organic pollutants within the range of the pollution plume.

[0023] A second aspect of the present invention provides a method for remediating organic pollution in groundwater, the method being implemented using the groundwater organic pollution remediation system described above, the method comprising:

[0024] The extraction module extracts organic pollutants from groundwater to create negative pressure, which affects the direction of groundwater flow, causing pollutants to accumulate and be fixed in the adsorption module.

[0025] The native bacterial strains in the organic-polluted groundwater extracted by the extraction module are expanded and cultured using the bacterial culture module.

[0026] Organically contaminated groundwater containing microorganisms, cultured in the microbial culture module, is injected into the biocontrol well to form a biodegradation barrier; and

[0027] Optionally, when the groundwater flow rate is too fast to ensure that pollutants are controlled within the range of the pollution plume, the hydraulic replenishment control module is used to pump water to control the flow field of the groundwater and control the organic pollutants within the range of the pollution plume.

[0028] Preferably, the method further includes: determining the effective adsorption residence time by detecting the dynamic adsorption law of the adsorption module under flow conditions, and causing the extraction module to intermittently extract the organic polluted groundwater according to the residence time.

[0029] According to the technical solution of this invention, a replaceable adsorption module is installed in a remediation well upstream of a pollution plume to treat the groundwater, which is contaminated with low concentrations of organic matter. The extracted groundwater enters a microbial culture module, enabling the rapid reproduction of indigenous organic matter-degrading microorganisms at the injection site. The cultured groundwater containing microorganisms is then injected into a downstream biocontrol well, allowing for continuous replenishment of the underground microbial culture and forming a biodegradation barrier that effectively intercepts pollution. An upstream hydraulic replenishment control module is installed to address hydraulic control failures in the remediation system, forming an integrated remediation system of adsorption, hydraulic control, and biodegradation. This system requires no large-scale underground engineering and provides continuous replenishment of biodegradable microorganisms. The integrated cultivation, expansion, and activation of microorganisms ensures the effectiveness of biodegradation, enabling specific control of different areas of the pollution plume. It is suitable for areas with rapid water return and high permeability, effectively controlling the spread of the pollution plume. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the operation process of the groundwater organic pollution remediation system described in this invention;

[0031] Figure 2 This is a schematic diagram of the structure of the groundwater organic pollution remediation system described in this invention.

[0032] Explanation of reference numerals in the attached figures

[0033] 1. Adsorption module; 2. Extraction module; 3. Microbial culture module; 4. Biocontrol module; 5. Hydraulic replenishment control module; 11. Porous frame; 12. Adsorption material; 21. Extraction pipeline; 22. Pollutant detection device; 23. Extraction pump; 31. Culture tank; 32. Adjustment device; 33. Pollutant and microbial abundance detection device; 41. Injection device; 42. Biocontrol well. Detailed Implementation

[0034] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0035] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0036] Existing technologies for groundwater organic matter remediation include numerous techniques, with biotechnology being widely used due to its environmentally friendly characteristics. However, all bio-based agents are not integrated with the injection environment, leading to issues with preservation and adaptability. Furthermore, phased or one-time injections cannot guarantee the sustained effectiveness of biodegradation, significantly reducing long-term efficacy. Moreover, existing technologies often have limitations in treating pollutant concentrations, failing to systematically remediate different locations within the pollution plume. This invention employs an adsorption-hydraulic control-biodegradation remediation system, specifically targeting different pollution concentration areas. It integrates the entire bio-process with the remediation technology, enabling continuous injection of biological strains to maintain the abundance of groundwater pollutant-degrading bacteria and ensure the effectiveness of the bio-process. The entire process does not involve large-scale underground engineering, minimizes groundwater disturbance, and is suitable for areas with rapid water return and high permeability.

[0037] Specifically, such as Figure 1 and 2 As shown, the groundwater organic pollution remediation system of the present invention includes:

[0038] Adsorption module 1 is placed in a groundwater well at the middle and upper reaches of the pollution plume;

[0039] Extraction module 2, connected to adsorption module 1, is used to extract organic pollutants from groundwater to create negative pressure, causing pollutants to accumulate and be fixed in adsorption module 1.

[0040] The microbial culture module 3 is used to expand the culture of native microbial strains in the organic polluted groundwater extracted by the extraction module 2.

[0041] The biocontrol module 4 includes an injection device 41 and a biocontrol well 42. The biocontrol well 42 is located downstream of the pollution plume. The injection device 41 is used to inject the organic polluted groundwater containing bacteria, which has been cultured by the bacterial culture module 3, into the biocontrol well 42.

[0042] The hydraulic replenishment control module 5 is located upstream of the pollution plume. Based on the groundwater flow velocity, it determines whether it is necessary to use the hydraulic replenishment control module 5 to pump water upstream of the pollution plume in order to control the organic pollutants within the range of the pollution plume.

[0043] The groundwater organic pollution remediation system according to this invention is based on a complete pollution plume. It utilizes existing groundwater wells to establish an adsorption-biodegradation-hydraulic control remediation system. The adsorption module 1 adsorbs and removes pollutants from groundwater with high concentrations of organic matter. The extraction module 2 creates negative pressure, causing the organic matter-contaminated groundwater to accumulate. Lower concentrations of organic matter-contaminated groundwater are extracted through the adsorption module 1 and injected into the microbial culture module 3. In the microbial culture module 3, local indigenous bacteria that degrade organic pollutants are cultured in the groundwater, partially degrading and removing the pollutants. The low-concentration organic matter-contaminated groundwater containing the bacteria is then reinjected into the downstream biocontrol well 42, forming a biodegradation barrier and intercepting the flow of pollutants to the remediation well. The entire process is uninterrupted, achieving continuous pollution control. Furthermore, the hydraulic replenishment control module 5 enhances hydraulic control, stabilizing pollutants within the pollution plume range and ensuring internal circulation of the organic matter-contaminated groundwater. The entire process requires no large-scale underground engineering, is simple in power, and can be effectively applied to the treatment of organic pollution in areas with rapid water return.

[0044] In the groundwater organic pollution remediation system of the present invention, the adsorption module 1 is placed in a groundwater well at the middle-upper position of the pollution plume, forming a remediation well. The middle-upper position of the pollution plume refers to the middle-upper direction of the original flow of organic pollutants in the groundwater, that is, in the high-concentration area of ​​the pollution. The adsorption module 1 includes a porous frame 11 and an adsorption material 12 filled in the porous frame 11. The adsorption material is preferably zeolite and / or hard activated carbon with high hardness. The particle size of the adsorption material is not less than 2 mm, more preferably not less than 3 mm, and even more preferably 3-20 mm. The selection of adsorption materials with high hardness and specific particle size requirements is to prevent the adsorption material from breaking due to the negative pressure caused by the connection of the extraction module. The porous frame 11 is preferably cylindrical, and its material is preferably PVC. In a further preferred embodiment, a lifting handle is provided on the top of the adsorption module 1, which facilitates the replacement of the adsorption material when it is saturated.

[0045] In the groundwater organic pollution remediation system of the present invention, the extraction module 2 includes an extraction pipe 21, a pollutant detection device 22 and an extraction pump 23. The inlet end of the extraction pipe 21 is connected to the adsorption module 1 and the outlet end is connected to the microbial culture module 3. The pollutant detection device 22 is used to detect the flow rate and pollutant content of the extracted organic pollutant groundwater.

[0046] In one specific embodiment, the extraction pump employs an intermittent lifting method. More preferably, the extraction pump is a solar-powered pump. During specific operation, by detecting the dynamic adsorption pattern of the adsorption module 1 under flow conditions, the effective adsorption residence time is determined, and the extraction pump intermittently extracts the organically polluted groundwater according to this residence time; the extraction flow rate of the extraction pump can be automatically adjusted.

[0047] In the extraction module 2, the pollutant detection device 22 can detect the flow rate and pollutant content of the extracted organic pollutant groundwater in real time. When the flow rate is not the set flow rate or the pollutant concentration increases significantly, the pollutant detection device 22 will sound an alarm and transmit the information to the management personnel. This may be because the adsorption material in the adsorption module 2 is saturated or new pollutants have been injected, reminding the management personnel to conduct further inspections or replace the adsorption material.

[0048] In the extraction module 2, the extraction pipe 21 is preferably made of PVC. The lower part of the extraction pipe 21 is inserted into the adsorption module 1, and a leak-proof screen is provided at the inlet to prevent the negative pressure from drawing in the adsorption material and causing blockage; and, the need for cleaning is determined periodically based on the flow detection results of the pollution detection device 22.

[0049] In the groundwater organic pollution remediation system described in this invention, the main function of the microbial culture module 3 is to expand the cultivation of native microbial species and degrade pollutants. By continuously injecting extracted organic polluted groundwater, the expansion cultivation of native microbial species is achieved, forming a microbial-containing organic polluted groundwater system. The microbial culture module 3 includes a culture tank 31, an adjustment device 32, and a pollutant and microbial abundance detection device 33. The inlet of the culture tank 31 is connected to the extraction module 2 (specifically, to the outlet end of the extraction pipe 21). The adjustment device 32 is used to control the addition of nutrients and adjust the water volume. The pollutant and microbial abundance detection device 33 is used to detect the concentration of pollutants, the content and activity of microbial species in the culture tank 31, and guides the operation of the adjustment device 32 based on the detection results.

[0050] In this invention, the culture tank 31 is a microbial culture tank for expansion. This part can be placed on the ground or underground, and its capacity can be set according to the flow rate.

[0051] In the groundwater organic pollution remediation system of the present invention, the biocontrol well 42 is located downstream of the remediation well. The pollutant concentration at this location must not be less than the concentration of organic pollutants in the groundwater containing microorganisms that have undergone microbial culture and are injected into the biocontrol well 42, to prevent the injection from aggravating the pollution. In a preferred embodiment, the number of biocontrol wells 42 is not less than 3, preferably 3-8.

[0052] In the groundwater organic pollution remediation system of the present invention, the hydraulic replenishment control module 5 includes one or more hydraulic replenishment control wells. When the groundwater flow velocity is too fast and it is impossible to ensure that the pollutants are controlled within the range of the pollution plume, water is pumped through the hydraulic replenishment control well upstream of the pollution plume to control the flow field of the groundwater and control the organic pollutants within the range of the pollution plume.

[0053] In one specific implementation, such as Figure 1 and 2 As shown, the groundwater organic pollution remediation system includes:

[0054] Adsorption module 1 is placed in a groundwater well at the middle and upper reaches of the pollution plume. The adsorption module 1 includes a porous frame 11 and an adsorption material 12 filled in the porous frame 11. The adsorption material 12 is zeolite with high hardness and / or hard activated carbon with a particle size of not less than 2 mm.

[0055] Extraction module 2, connected to adsorption module 1, is used to extract organic pollutant groundwater to create negative pressure, causing pollutants to accumulate and fix on adsorption module 1. Extraction module 2 includes extraction pipe 21, pollutant detection device 22, and extraction pump 23. The inlet end of extraction pipe 21 is connected to adsorption module 1, and the outlet end is connected to microbial culture module 3. Pollutant detection device 22 is used to detect the flow rate and pollutant content of the extracted organic pollutant groundwater.

[0056] The microbial culture module 3 is used to expand the culture of native microbial strains in the organic polluted groundwater extracted by the extraction module 2. The microbial culture module 3 includes a culture tank 31, an adjustment device 32, and a pollutant and microbial abundance detection device 33. The inlet of the culture tank 31 is connected to the extraction module 2 (specifically, to the outlet end of the extraction pipe 21). The adjustment device 32 is used to control the addition of nutrients and adjust the water volume. The pollutant and microbial abundance detection device 33 is used to detect the concentration of pollutants, the content and activity of microorganisms in the culture tank 31, and guide the operation of the adjustment device 32 based on the detection results.

[0057] The biocontrol module 4 includes an injection device 41 and a biocontrol well 42. The biocontrol well 42 is located downstream of the pollution plume. The injection device 41 is used to inject the organic polluted groundwater containing bacteria, which has been cultured by the bacterial culture module 3, into the biocontrol well 42. The number of biocontrol wells 42 is not less than 3.

[0058] The hydraulic replenishment control module 5 includes one or more hydraulic replenishment control wells located upstream of the pollution plume. Based on the groundwater flow velocity, it is determined whether the hydraulic replenishment control module 5 needs to pump water upstream of the pollution plume to control the organic pollutants within the range of the pollution plume. Specifically, when the groundwater flow velocity is too fast to ensure that the pollutants are controlled within the range of the pollution plume, water is pumped through the hydraulic replenishment control wells upstream of the pollution plume to control the groundwater flow field and thus control the organic pollutants within the range of the pollution plume.

[0059] In another specific implementation, such as Figure 1 and 2 As shown, the groundwater organic pollution remediation system includes:

[0060] Adsorption module 1 is placed in a groundwater well at the middle and upper reaches of the pollution plume. The adsorption module 1 includes a porous frame 11 and an adsorption material 12 filled in the porous frame 11. The adsorption material 12 is zeolite and / or hard activated carbon with a particle size of 2-20 mm. The porous frame 11 is cylindrical and made of PVC. The adsorption module 1 is provided with a lifting handle at the top, which makes it easy to replace the adsorption material when it is saturated.

[0061] Extraction module 2, connected to adsorption module 1, is used to extract organic pollutant groundwater to create negative pressure, causing pollutants to accumulate and fix on adsorption module 1. Extraction module 2 includes extraction pipe 21, pollutant detection device 22, and extraction pump 23. The inlet end of extraction pipe 21 is connected to adsorption module 1, and the outlet end is connected to microbial culture module 3. Pollutant detection device 22 is used to detect the flow rate and pollutant content of the extracted organic pollutant groundwater. Extraction pump is a solar-powered pump.

[0062] The microbial culture module 3 is used to expand the culture of native microbial strains in the organic polluted groundwater extracted by the extraction module 2. The microbial culture module 3 includes a culture tank 31, an adjustment device 32, and a pollutant and microbial abundance detection device 33. The inlet of the culture tank 31 is connected to the extraction module 2 (specifically, to the outlet end of the extraction pipe 21). The adjustment device 32 is used to control the addition of nutrients and adjust the water volume. The pollutant and microbial abundance detection device 33 is used to detect the concentration of pollutants, the content and activity of microorganisms in the culture tank 31, and guide the operation of the adjustment device 32 based on the detection results.

[0063] The biocontrol module 4 includes an injection device 41 and a biocontrol well 42. The biocontrol well 42 is located downstream of the pollution plume. The injection device 41 is used to inject the organic polluted groundwater containing bacteria, which has been cultured by the bacterial culture module 3, into the biocontrol well 42. The number of biocontrol wells 42 is 3-8.

[0064] The hydraulic replenishment control module 5 includes one or more hydraulic replenishment control wells located upstream of the pollution plume. Based on the groundwater flow velocity, it is determined whether the hydraulic replenishment control module 5 needs to pump water upstream of the pollution plume to control the organic pollutants within the range of the pollution plume. Specifically, when the groundwater flow velocity is too fast to ensure that the pollutants are controlled within the range of the pollution plume, water is pumped through the hydraulic replenishment control wells upstream of the pollution plume to control the groundwater flow field and thus control the organic pollutants within the range of the pollution plume.

[0065] The present invention also provides a method for remediating groundwater organic pollution using the above-mentioned groundwater organic pollution remediation system, the method comprising:

[0066] The extraction module extracts organic pollutants from groundwater to create negative pressure, which affects the direction of groundwater flow, causing pollutants to accumulate and be fixed in the adsorption module.

[0067] The native bacterial strains in the organic-polluted groundwater extracted by the extraction module are expanded and cultured using the bacterial culture module.

[0068] Organically contaminated groundwater containing microorganisms, cultured in the microbial culture module, is injected into the biocontrol well to form a biodegradation barrier; and

[0069] Optionally, when the groundwater flow rate is too fast to ensure that pollutants are controlled within the range of the pollution plume, the hydraulic replenishment control module is used to pump water to control the flow field of the groundwater and control the organic pollutants within the range of the pollution plume.

[0070] In a specific implementation, the method further includes: determining the effective adsorption residence time by detecting the dynamic adsorption law of the adsorption module under flow conditions, and causing the extraction module to intermittently extract the organic polluted groundwater according to the residence time.

[0071] In the groundwater organic pollution remediation method described in this invention, the groundwater extracted by the extraction module is used as raw material for subsequent microbial culture. The extracted groundwater contains local microbial strains. After a scaling-up culture process, most of the pollutants in the extracted groundwater are degraded. Subsequently, the groundwater, along with the local microbial strains, is reinjected downstream of the pollutants to form a biodegradation barrier. In this invention, no additional treatment is required for the extracted groundwater. The scaling-up culture of degradation microbial strains (local microbial strains) adapted to local conditions is achieved in situ, and the groundwater is reinjected to achieve biodegradation. The entire process can be carried out continuously without the need for additional treatment processes.

[0072] According to the groundwater organic pollution remediation method described in this invention, based on groundwater wells, different remediation modules are formed for different pollutant concentration zones in the pollution plume, which can effectively remove pollutants. Hydraulic control can effectively control pollutants in the existing system of the pollution plume. Continuous and uninterrupted injection of biological strains ensures the pollution remediation effect downstream and forms an effective biodegradation barrier. The whole process has low cost and high safety factor, and is suitable for production enterprises in areas with rapid water return and high permeability.

[0073] The following examples further illustrate the groundwater organic pollution remediation system and method of the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0074] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0075] Example 1

[0076] After a detailed site investigation, the location and distribution of the pollution plume from Company A were determined. The investigation revealed that Company A is located in a highly permeable stratum with rapid water return, making it suitable for the technical solution of this invention.

[0077] An adsorption module was placed in a groundwater well located in the middle to upper reaches of the pollution plume. Zeolite particles with a diameter of 3 mm were placed inside the adsorption module, and an extraction module was connected to it. Groundwater was slowly extracted, creating negative pressure that affected the water flow direction, causing pollutants to accumulate in the adsorption module and be adsorbed by the adsorption material. By changing the flow rate and residence time, the pollution concentration was measured using a pollution detection device on the extraction module. Measurements showed that when the residence time was 10 minutes, the pollutant concentration decreased to 20% of its pre-adsorption value. Reducing the residence time resulted in a rapid increase in the extracted water concentration. Therefore, the extraction pulse boost time was set to 10 minutes, and the pollutant concentration and pumping flow rate were measured using the pollutant detection device. The extracted low-concentration organic-contaminated groundwater was introduced into a microbial culture module. Due to the large open area surrounding the contaminated area, the culture tanks were placed directly on the ground to expand the cultivation of native degrading bacteria in the water. Measurements using pollutant and microbial abundance detection devices showed that the pollutant concentration had decreased to 70% of the inlet concentration, and the microbial abundance was good, thus requiring no additional adjustment. The cultured organic-contaminated groundwater containing microorganisms was continuously reinjected into the biocontrol well downstream of the contamination plume, forming a natural biodegradation barrier and supplementing routine monitoring at downstream sites to monitor the pollution effect. Results showed that, over time, downstream monitoring results indicated a gradual decrease in pollution concentration. After 6 months, the downstream pollution level fell below the national Class III water standard limit. In the relatively severely polluted areas upstream and midstream of the contamination plume, pollutant concentrations decreased rapidly, with a 60% reduction in pollution within half a month and a 90% reduction after 6 months.

[0078] Example 2

[0079] After a detailed site investigation, the location and distribution of the pollution plume from Company B were determined. The investigation revealed that Company B is located in a highly permeable stratum with rapid water return, making it suitable for the technical solution of this invention.

[0080] An adsorption module was placed in a groundwater well located in the middle to upper reaches of the pollution plume. Zeolite particles with a diameter of 2.5 mm were placed inside the adsorption module, and an extraction module was connected to it. Groundwater was slowly extracted, creating negative pressure that affected the water flow direction, causing pollutants to accumulate in the adsorption module and be adsorbed by the adsorption material. By changing the flow rate and residence time, the pollution concentration was measured using a pollution detection device on the extraction module. Measurements showed that when the residence time was 9 minutes, the pollutant concentration decreased to 18% of its pre-adsorption value. Reducing the residence time resulted in a rapid increase in the extracted water concentration. Therefore, the extraction pulse boost time was set to 9 minutes, and the pollutant concentration and pumping flow rate were measured using the pollutant detection device. Low-concentration organic polluted groundwater was extracted and fed into a microbial culture module. Due to the large open area surrounding the pollution site, the culture tanks were placed directly on the ground to expand the cultivation of native degrading bacteria in the water. Measurements using pollutant and microbial abundance detection devices showed that the pollutant concentration had decreased to 73% of the inlet concentration, and the microbial abundance was good, thus requiring no additional adjustment. The cultured organic polluted groundwater containing microorganisms was continuously reinjected into the biocontrol well downstream of the pollution plume, forming a natural biodegradation barrier and supplementing routine monitoring at downstream sites to monitor the pollution effect. Results showed that, over time, downstream monitoring results indicated a gradual decrease in pollution concentration. After 6 months, the downstream pollution level fell below the national Class III water standard limit. In the relatively severely polluted areas upstream and midstream of the pollution plume, pollutant concentrations decreased rapidly, with a 65% reduction in pollution within half a month and a 92% reduction after 6 months.

[0081] Example 3

[0082] After a detailed site investigation, the location and distribution of the pollution plume from Company C were determined. The investigation revealed that Company C is located in a highly permeable stratum with rapid water return, making it suitable for the technical solution of this invention.

[0083] An adsorption module was placed in a groundwater well located in the middle to upper reaches of the pollution plume. Zeolite particles with a diameter of 2 mm were placed inside the adsorption module, and an extraction module was connected to it. Groundwater was slowly extracted, creating negative pressure that affected the water flow direction, causing pollutants to accumulate in the adsorption module and be adsorbed by the adsorption material. By changing the flow rate and residence time, the pollution concentration was measured using a pollution detection device on the extraction module. Measurements showed that when the residence time was 8 minutes, the pollutant concentration decreased to 16% of its pre-adsorption value. Reducing the residence time resulted in a rapid increase in the extracted water concentration. Therefore, the extraction pulse boost time was set to 8 minutes, and the pollutant concentration and pumping flow rate were measured using the pollutant detection device. The extracted low-concentration organic-contaminated groundwater was introduced into a microbial culture module. Due to the large open area surrounding the contaminated area, the culture tanks were placed directly on the ground to expand the cultivation of native degrading bacteria in the water. Measurements using pollutant and microbial abundance detection devices showed that the pollutant concentration had decreased to 75% of the inlet concentration, and the microbial abundance was good, thus requiring no additional adjustment. The cultured organic-contaminated groundwater containing microorganisms was continuously reinjected into the biocontrol well downstream of the contamination plume, forming a natural biodegradation barrier and supplementing routine monitoring at downstream sites to monitor the pollution effect. Results showed that, over time, downstream monitoring results indicated a gradual decrease in pollution concentration. After 6 months, the downstream pollution level fell below the national Class III water standard limit. In the relatively severely polluted areas upstream and midstream of the contamination plume, pollutant concentrations decreased rapidly, with a 63% reduction in pollution within half a month and a 90% reduction after 6 months.

[0084] Example 4

[0085] After a detailed site investigation, the location and distribution of the pollution plume from Company D were determined. The investigation revealed that Company D is located in a highly permeable stratum with rapid water return, making it suitable for the technical solution of this invention.

[0086] An adsorption module was placed in a groundwater well located in the middle to upper reaches of the pollution plume. Hard activated carbon with a particle size of 2mm was placed inside the adsorption module, and an extraction module was connected to it. Groundwater was slowly extracted, creating negative pressure that affected the water flow direction, causing pollutants to accumulate in the adsorption module and be adsorbed by the adsorption material. By changing the flow rate and residence time, the pollution concentration was measured by the pollution detection device in the extraction module. It was found that when the residence time was 9 minutes, the pollutant concentration decreased to 15% of the pre-adsorption level. Reducing the residence time resulted in a rapid increase in the extracted water concentration. Therefore, the extraction pulse interval was set to 9 minutes, and the pollutant concentration and pumping flow rate were measured using the pollutant detection device. After a period of operation, it was found that the pollutant concentration gradually increased. Therefore, the system was shut down for repair, the adsorption material was replaced, and the flow rate and effluent concentration were readjusted. After testing, the pulse interval was changed to 7 minutes. The extracted low-concentration organic-contaminated groundwater was introduced into a microbial culture module. Due to the large open area surrounding the contaminated area, the culture tank was placed directly on the ground to expand the cultivation of native degrading bacteria in the water. Pollutant and microbial abundance detection devices determined that the pollutant concentration had decreased to 80% of the inlet concentration, and the microbial abundance was good, thus requiring no additional adjustment. The cultured organic-contaminated groundwater containing microorganisms was continuously reinjected into the biocontrol well downstream of the contamination plume, forming a natural biodegradation barrier and supplementing routine monitoring at downstream sites to monitor the pollution effect. Results showed that, over time, downstream monitoring results indicated a gradual decrease in pollution concentration. After three months, the downstream pollution level fell below the national Class III water standard, meeting remediation expectations. In the relatively severely polluted areas upstream and midstream of the contamination plume, pollutant concentrations decreased rapidly, with a 60% reduction within half a month. Afterward, the pollutant concentration decreased slowly, requiring replacement of the adsorption material. Three months after replacement, the pollutant concentration decreased by 80%.

[0087] Example 5

[0088] After a detailed site investigation, the location and distribution of the pollution plume from Company E were determined. The investigation revealed that Company E is located in a highly permeable stratum with rapid water return, making it suitable for the technical solution of this invention.

[0089] An adsorption module was placed in a groundwater well located in the middle to upper reaches of the pollution plume. Hard activated carbon with a particle size of 2.5 mm was placed inside the adsorption module, and an extraction module was connected to it. Groundwater was slowly extracted, creating negative pressure that affected the water flow direction, causing pollutants to accumulate in the adsorption module and be adsorbed by the adsorption material. By changing the flow rate and residence time, the pollution concentration was measured by the pollution detection device in the extraction module. It was found that when the residence time was 10 minutes, the pollutant concentration decreased to 18% of the pre-adsorption level. Reducing the residence time resulted in a rapid increase in the extracted water concentration. Therefore, the extraction pulse interval was set to 10 minutes, and the pollutant concentration and pumping flow rate were measured using the pollutant detection device. After a period of operation, it was found that the pollutant concentration gradually increased. Therefore, the system was shut down for repair, the adsorption material was replaced, and the flow rate and effluent concentration were readjusted. After testing, the pulse interval was changed to 8 minutes. Low-concentration organic polluted groundwater was extracted and fed into a microbial culture module. Due to the large open area surrounding the pollution site, the culture tank was placed directly on the ground to expand the cultivation of native degrading bacteria in the water. Pollutant concentration was measured to be 75% of the inlet concentration using pollutant and microbial abundance detection devices, indicating good microbial abundance. Therefore, no additional adjustment was needed. The cultured organic polluted groundwater containing microorganisms was continuously reinjected into the biocontrol well downstream of the pollution plume, forming a natural biodegradation barrier and supplementing routine monitoring at downstream sites to monitor the pollution effect. Results showed that the pollution concentration at downstream sites gradually decreased over time. After three months, the downstream pollution level was below the national Class III water standard, meeting remediation expectations. In the relatively severely polluted areas upstream and midstream of the pollution plume, pollutant concentrations decreased rapidly, with a 62% reduction within half a month. Afterward, the pollutant concentration decreased slowly, requiring replacement of the adsorption material. Three months after replacement, the pollutant concentration decreased by 83%.

[0090] Example 6

[0091] After a detailed site investigation, the location and distribution of the pollution plume from Company F were determined. The investigation revealed that Company F was located in a highly permeable stratum with rapid water return, making it suitable for the technical solution of this invention.

[0092] An adsorption module was placed in a groundwater well located in the middle to upper reaches of the pollution plume. Hard activated carbon with a particle size of 3mm was placed inside the adsorption module, and an extraction module was connected to it. Groundwater was slowly extracted, creating negative pressure that affected the water flow direction, causing pollutants to accumulate in the adsorption module and be adsorbed by the adsorption material. By changing the flow rate and residence time, the pollution concentration was measured by the pollution detection device in the extraction module. It was found that when the residence time was 12 minutes, the pollutant concentration decreased to 15% of the pre-adsorption level. Reducing the residence time resulted in a rapid increase in the extracted water concentration. Therefore, the extraction pulse interval was set to 12 minutes, and the pollutant concentration and pumping flow rate were measured using the pollutant detection device. After a period of operation, it was found that the pollutant concentration gradually increased. Therefore, the system was shut down for repair, the adsorption material was replaced, and the flow rate and effluent concentration were readjusted. After testing, the pulse interval was changed to 10 minutes. The extracted low-concentration organic-contaminated groundwater was introduced into a microbial culture module. Due to the large open area surrounding the contaminated area, the culture tank was placed directly on the ground to expand the cultivation of native degrading bacteria in the water. Pollutant concentration was measured to be 78% of the inlet concentration using pollutant and microbial abundance detection devices, indicating good microbial abundance. Therefore, no additional adjustment was required. The cultured organic-contaminated groundwater containing microorganisms was continuously reinjected into the biocontrol well downstream of the contamination plume, forming a natural biodegradation barrier and supplementing routine monitoring at downstream sites to monitor the pollution effect. Results showed that the pollution concentration at downstream sites gradually decreased over time. After three months, the downstream pollution level was below the national Class III water standard, meeting the remediation expectations. In the relatively severely polluted areas upstream and midstream of the contamination plume, pollutant concentrations decreased rapidly, with a 65% reduction within half a month. Afterward, the pollutant concentration decreased slowly, and the adsorption material was replaced again. Three months after the replacement, the pollutant concentration decreased by 85%.

[0093] Example 7

[0094] After a detailed site investigation, the location and distribution of the pollution plume from Company G were determined. The investigation revealed that Company G is located in a highly permeable stratum with rapid water return, making it suitable for the technical solution of this invention.

[0095] An adsorption module was placed in a groundwater well located in the middle to upper reaches of the pollution plume. Zeolite particles with a diameter of 2.5 mm were placed inside the adsorption module, and an extraction module was connected to it. Groundwater was slowly extracted, creating negative pressure that affected the water flow direction, causing pollutants to accumulate in the adsorption module and be adsorbed by the adsorption material. By changing the flow rate and residence time, the pollution concentration was measured using a pollution detection device on the extraction module. Measurements showed that when the residence time was 7 minutes, the pollutant concentration decreased to 15% of its pre-adsorption value. Reducing the residence time resulted in a rapid increase in the extracted water concentration. Therefore, the extraction pulse boost time was set to 7 minutes, and the pollutant concentration and pumping flow rate were measured using the pollutant detection device. Low-concentration organic polluted groundwater was extracted and fed into a microbial culture module. Due to the large open area surrounding the pollution site, the culture tank was placed directly on the ground to expand the cultivation of native degrading bacteria in the water. Pollutant and microbial abundance detection devices showed that the pollutant concentration had decreased to 90% of the inlet concentration. However, significant microbial mortality necessitated additional adjustments. N / P nutrients were added through an adjustment device, increasing microbial abundance. The cultured organic polluted groundwater containing microorganisms was then continuously reinjected into the biocontrol well downstream of the pollution plume, forming a natural biodegradation barrier and supplementing routine monitoring at downstream sites to assess the pollution effect. Results showed that downstream monitoring showed a slow reduction in pollution concentration. Further increases in nutrients to enhance microbial abundance in the reinjected water resulted in downstream pollution levels falling below the national Class III water standard after four months. In contrast, pollutant concentrations in the relatively heavily polluted upper and middle reaches of the pollution plume decreased rapidly, with a 70% reduction within half a month. Afterward, the pollutant concentration reduction slowed, requiring replacement of the adsorption material. Two months after replacement, the pollutant concentration decreased by 90%.

[0096] Example 8

[0097] After a detailed site investigation, the location and distribution of the pollution plume from Company H were determined. The investigation revealed that Company H is located in a highly permeable stratum with rapid water return, making it suitable for the technical solution of this invention.

[0098] An adsorption module was placed in a groundwater well located in the middle to upper reaches of the pollution plume. Zeolite particles with a diameter of 2 mm were placed inside the adsorption module, and an extraction module was connected to it. Groundwater was slowly extracted, creating negative pressure that affected the water flow direction, causing pollutants to accumulate in the adsorption module and be adsorbed by the adsorption material. By changing the flow rate and residence time, the pollution concentration was measured using a pollution detection device on the extraction module. Measurements showed that when the residence time was 8 minutes, the pollutant concentration decreased to 18% of its pre-adsorption value. Reducing the residence time resulted in a rapid increase in the extracted water concentration. Therefore, the extraction pulse boost time was set to 8 minutes, and the pollutant concentration and pumping flow rate were measured using the pollutant detection device. Low-concentration organic polluted groundwater was introduced into a microbial culture module. Due to the large open area surrounding the pollution site, the culture tank was placed directly on the ground to expand the cultivation of native degrading bacteria in the water. Pollutant and microbial abundance detection devices showed that the pollutant concentration had decreased to 90% of the inlet concentration. However, significant bacterial mortality necessitated additional adjustments. N / P nutrients were added through the adjustment device, increasing microbial abundance. The cultured organic polluted groundwater containing microorganisms was then continuously reinjected into the biocontrol well downstream of the pollution plume, forming a natural biodegradation barrier and supplementing routine monitoring at downstream sites to assess the pollution effect. Results showed that downstream monitoring showed a slow reduction in pollution concentration. Further increases in nutrients to enhance microbial abundance in the reinjected water resulted in downstream pollution levels falling below the national Class III water standard after four months. In contrast, pollutant concentrations in the relatively heavily polluted upper and middle reaches of the pollution plume decreased rapidly, with a 72% reduction within half a month. Afterward, the pollutant concentration reduction slowed, requiring replacement of the adsorption material. Two months after replacement, the pollutant concentration decreased by 93%.

[0099] Example 9

[0100] After a detailed site investigation, the location and distribution of the pollution plume from Company I were determined. The investigation revealed that Company I is located in a highly permeable stratum with rapid water return, making it suitable for the technical solution of this invention.

[0101] An adsorption module was placed in a groundwater well located in the middle to upper reaches of the pollution plume. Zeolite particles with a diameter of 3 mm were placed inside the adsorption module, and an extraction module was connected to it. Groundwater was slowly extracted, creating negative pressure that affected the water flow direction, causing pollutants to accumulate in the adsorption module and be adsorbed by the adsorption material. By changing the flow rate and residence time, the pollution concentration was measured using a pollution detection device on the extraction module. Measurements showed that when the residence time was 10 minutes, the pollutant concentration decreased to 20% of its pre-adsorption value. Reducing the residence time resulted in a rapid increase in the extracted water concentration. Therefore, the extraction pulse boost time was set to 10 minutes, and the pollutant concentration and pumping flow rate were measured using the pollutant detection device. Low-concentration organic polluted groundwater was introduced into a microbial culture module. Due to the large open area surrounding the pollution site, the culture tank was placed directly on the ground to expand the cultivation of native degrading bacteria in the water. Pollutant and microbial abundance detection devices showed that the pollutant concentration had decreased to 90% of the inlet concentration. However, significant microbial mortality necessitated additional adjustments. N / P nutrients were added through an adjustment device to increase microbial abundance. The cultured organic polluted groundwater containing microorganisms was then continuously reinjected into the biocontrol well downstream of the pollution plume, forming a natural biodegradation barrier and supplementing routine monitoring at downstream sites to assess the pollution effect. Results showed that downstream monitoring showed a slow reduction in pollution concentration. Further increases in nutrients to enhance microbial abundance in the reinjected water resulted in downstream pollution levels falling below the national Class III water standard after four months. In contrast, pollutant concentrations in the relatively heavily polluted upstream and midstream areas of the pollution plume decreased rapidly, with a 75% reduction within half a month. Afterward, the pollutant concentration reduction slowed, requiring replacement of the adsorption material. Two months after replacement, the pollutant concentration decreased by 95%.

[0102] As can be seen from the above embodiments, the groundwater organic pollution remediation system and method according to the present invention, based on groundwater wells, forms different remediation modules for different pollutant concentration zones in the pollution plume, which can effectively remove pollutants. Hydraulic control can effectively control pollutants in the existing system of the pollution plume. Continuous and uninterrupted injection of biological strains ensures the downstream pollution remediation effect and forms an effective biodegradation barrier.

[0103] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A groundwater organic contamination remediation system characterized by, The application relates to a system for repairing organic-polluted groundwater, which comprises the following modules: an adsorption module, which is arranged in a groundwater well at an upper-middle position of a pollution plume; an extraction module, which is connected with the adsorption module and is used for extracting organic-polluted groundwater to form a negative pressure, so that pollutants are gathered and fixed in the adsorption module; a strain culture module, which is used for expanding culture of native strains in the organic-polluted groundwater extracted by the extraction module; a biological control module, which comprises an injection device and a biological control well, the biological control well is arranged at a downstream position of the pollution plume, and the injection device is used for injecting the organic-polluted groundwater containing the strains cultured by the strain culture module into the biological control well; and a hydraulic supplement control module, which is arranged at an upstream position of the pollution plume, and comprises one or more hydraulic supplement control wells, when the groundwater flow velocity is too high to ensure that the pollutants are controlled in the range of the pollution plume, the hydraulic supplement control wells at the upstream position of the pollution plume are used for pumping water, so that the flow field of the groundwater is controlled, and the organic pollutants are controlled in the range of the pollution plume. The adsorption module comprises a porous frame and adsorption material filled in the porous frame. The adsorption material is zeolite and / or hard activated carbon, and the particle size is not less than 2 mm. The porous frame is in a cylindrical shape and is made of PVC. The extraction module comprises an extraction pipeline, a pollutant detection device and an extraction pump, the inlet end of the extraction pipeline is connected with the adsorption module, the outlet end is connected with the strain culture module, and the pollutant detection device is used for detecting the flow and pollutant content of the extracted organic-polluted groundwater. The extraction pump adopts an intermittent lifting mode.

2. The groundwater organic contamination remediation system of claim 1, wherein, The extraction pump is a solar-powered pump.

3. The groundwater organic contamination remediation system of claim 2, wherein, A leakage-proof net is arranged at the inlet of the extraction pipeline.

4. The groundwater organic contamination remediation system of claim 2, wherein, The strain culture module comprises a culture pool, a regulating device and a pollutant and strain abundance detection device, the inlet of the culture pool is connected with the extraction module, the regulating device is used for controlling the addition of a nutrient agent and regulating water volume, and the pollutant and strain abundance detection device is used for detecting the pollutant concentration and strain content and activity in the culture pool, and guiding the operation of the regulating device according to the detection results.

5. The groundwater organic contamination remediation system of claim 1, wherein, The biological control module comprises at least three biological control wells.

6. The groundwater organic contamination remediation system of claim 5, wherein, The method is implemented by using the groundwater organic pollution repairing system in any one of claims 1-10, and the method comprises the following steps:

7. The groundwater organic contamination remediation system of claim 6, wherein, The organic-polluted groundwater is extracted by the extraction module to form a negative pressure, so as to affect the water flow direction of the groundwater, gather and fix the pollutants in the adsorption module; 8. The groundwater organic contamination remediation system of any one of claims 5-7, wherein, The native strains in the organic-polluted groundwater extracted by the extraction module are expanded and cultured by the strain culture module; 9. The groundwater organic contamination remediation system of claim 1, wherein, The organic-polluted groundwater containing the strains cultured by the strain culture module is injected into the biological control well to form a biological degradation barrier; and 10. The groundwater organic contamination remediation system of claim 1, wherein, When the groundwater flow velocity is too high to ensure that the pollutants are controlled in the range of the pollution plume, the hydraulic supplement control module is used for pumping water, so that the flow field of the groundwater is controlled, and the organic pollutants are controlled in the range of the pollution plume.

11. A method for remediation of groundwater contaminated with organic pollutants, characterized in that, ​ ​ ​ ​ ​ 12. The method of claim 11, wherein, The method further comprises: determining the effective residence time by detecting the dynamic adsorption law of the adsorption module under the flowing condition, and making the extraction module intermittently extract the organic contaminated groundwater according to the residence time.

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