Organic contaminated site soil-water synergistic in-situ remediation device and method

Abstract

The application provides an organic contaminated site soil-water synergic in-situ remediation device and a remediation method. The remediation device comprises a detection assembly, a steam generator, a multi-phase extraction well and an ozone bubble generator. The application adopts a remediation strategy of first remediation of soil and then remediation of underground water, realizes pollution prevention and control of contaminated soil and underground water, soil-water synergic integrated remediation and multi-technology coupling, and has the advantages of green and sustainable development.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental remediation, in particular to a soil and groundwater cooperative in-situ remediation device and method for organic contaminated sites. BACKGROUND

[0002] Soil and groundwater pollution is an important environmental problem, and the remediation of soil and groundwater pollution is one of the hot and difficult problems in the field of environment. The number of organic contaminated sites generated by industries such as chemical industry and smelting is huge, which not only restricts the economic development, but also poses a great threat to the health of residents. Therefore, developing efficient remediation technology for organic contaminated soil and groundwater is an urgent problem to be solved in environmental geotechnics.

[0003] Due to the complexity of production process, industrial contaminated sites have the modern environmental pollution characteristics of multi-source, large area, large quantity, persistence, and high toxicity. The main pollutants are polycyclic aromatic hydrocarbons, petroleum hydrocarbons, benzene series, and chlorinated hydrocarbons. In addition, due to the leakage, discharge or disposal of wastewater or solid waste containing organic pollutants during production and use, the soil and groundwater of industrial sites are seriously polluted, making the remediation extremely difficult. In addition, most of the contaminated sites are non-homogeneous, with low-permeability media such as fine-grained soil and clay, which control the distribution and enrichment of organic pollutants, making the remediation efficiency of single organic contaminated soil or groundwater remediation technology greatly limited. Therefore, it is necessary to develop soil and groundwater cooperative integration for efficient remediation of industrial complex organic contaminated sites.

[0004] At present, a lot of research work has been carried out on the multi-technology coupling remediation of organic contaminated soil or groundwater. For organic contaminated soil, common coupling remediation technologies include the coupling of physical remediation technology and chemical remediation technology, and the coupling of physical remediation technology and microbial remediation technology, such as heat steam injection coupled with chemical oxidation remediation technology, which uses heat steam to rapidly raise the temperature of contaminated soil, and then injects oxidizing agents such as persulfate, to activate the chemical oxidizing agent by heat, and improve the degradation effect of pollutants. The coupling of physical remediation technology and biological remediation technology, such as heat-enhanced microbial remediation technology, which uses low-temperature thermal desorption remediation technology to raise the soil temperature to a suitable temperature range, can promote the enrichment of enzymes, the production of extracellular polysaccharides and biosurfactants, and thus enhance the remediation effect of microbial remediation technology. For organic contaminated groundwater, common coupling technologies include the coupling of physical remediation technology, chemical remediation technology and microbial remediation technology, such as electrokinetic remediation combined with zero-valent nano-iron remediation technology, which can affect the life and migration of zero-valent nano-iron, drive zero-valent nano-iron to degrade chlorinated hydrocarbons, and change the chemical conditions of the aquifer to promote the reproduction of soil organic halogen respiration bacteria.

[0005] However, the current development of multi-technology coupling remediation technology is mainly for organic contaminated soil or groundwater, and the soil-water integrated remediation is not considered. Soil-water integrated multi-technology coupling remediation is one of the important ways to realize the green and sustainable transformation of industrial contaminated site remediation mode, and is the core concept of efficient remediation and low-carbon energy saving. Industrial sites often have serious soil and groundwater pollution, and how to provide a soil-water integrated multi-technology coupling remediation device and process has become a technical problem that needs to be solved urgently. SUMMARY

[0006] Therefore, it is necessary to provide an organic contaminated site soil-water integrated in-situ remediation device and method to realize integrated remediation of soil and groundwater.

[0007] The above invention purposes can be realized by the following technical solutions.

[0008] In a first aspect, the application provides an organic contaminated site soil-water integrated in-situ remediation device, which comprises a detection assembly, a steam generator, a multi-phase extraction well and an ozone bubble generator.

[0009] The detection assembly comprises a soil detector and a groundwater detector, the soil detector is used to detect the concentration of pollutants in the soil, and the groundwater detector is used to detect the pollution concentration of the groundwater.

[0010] The steam generator is connected with a steam injection well, the steam injection well is arranged at the upstream section of the groundwater, and the steam injection well comprises a soil steam injection section and a groundwater steam injection section.

[0011] Along the flow direction of the groundwater, the multi-phase extraction well is arranged at the downstream section of the steam injection well, the multi-phase extraction well comprises a soil multi-phase extraction well and a groundwater multi-phase extraction well, the soil multi-phase extraction well is buried in the soil and used to extract and remove the pollutants in the soil, and the soil multi-phase extraction well is immersed in the groundwater and used to extract and remove the pollutants in the groundwater.

[0012] The ozone bubble generator is connected with an ozone injection well, and the ozone injection well is immersed in the upstream section of the groundwater.

[0013] In some embodiments, the remediation device further comprises a permeable reaction barrier, which is arranged at the downstream section of the multi-phase extraction well along the flow direction of the groundwater, and the permeable reaction barrier is used to filter the groundwater to remove the pollutants.

[0014] Optionally, the permeable reaction barrier is filled with an oxidizing agent.

[0015] In some embodiments, the remediation device further comprises a monitoring well disposed downstream of the permeable reactive barrier, the monitoring well configured to detect microbial colonies and oxygen levels in the groundwater.

[0016] In some embodiments, the groundwater detector comprises at least one of a contaminant concentration sensor, an oxygen concentration sensor, a pH sensor, a microbial community sensor, and an electrical potential sensor.

[0017] In some embodiments, the steam generated by the steam generator comprises at least one of propylene glycol, water, and air.

[0018] In some embodiments, the remediation device further comprises a permeable reactive barrier and a monitoring well, and the method of remediation comprises:

[0019] After detecting the contaminant concentration in the soil and groundwater, the steam is used to evaporate and remove the contaminants in the soil, and the soil is extracted to remove the contaminants;

[0020] After the soil remediation is completed, the steam is used to evaporate and remove the contaminants in the groundwater, and the groundwater is extracted to remove the contaminants, and after the contaminants in the groundwater are removed, ozone bubbles are introduced into the groundwater, and the remediation of the soil and groundwater is completed by monitoring the natural attenuation.

[0021] In some embodiments, the remediation device further comprises a permeable reactive barrier and a monitoring well, and the method of remediation comprises:

[0022] S100, detecting the contaminant concentration in the soil and groundwater, determining whether the contaminant concentration in the soil reaches a soil remediation preset value, if yes, proceeding to S101, if not, proceeding to S200;

[0023] S101, starting the steam generator, injecting steam into the soil steam injection section to evaporate and remove the contaminants in the soil, and opening the soil multi-phase extraction well to extract and remove the contaminants in the soil; when it is detected that the contaminant concentration in the soil reaches a soil remediation target value, proceeding to S200;

[0024] S200, starting the steam generator, injecting steam into the groundwater steam injection section to evaporate and remove the contaminants in the groundwater, and opening the groundwater multi-phase extraction well to extract and remove the contaminants in the groundwater; when it is detected that the contaminant concentration in the groundwater at the monitoring well reaches a first groundwater remediation target value, proceeding to S201;

[0025] S201, start the ozone bubble generator, inject ozone bubbles into the groundwater through the ozone injection well, and start the groundwater multi-phase extraction well; when the oxygen content, microbial community and organic pollutant concentration in the groundwater at the monitoring well meet the requirements of microbial remediation, stop injecting ozone bubbles into the groundwater; monitor the degradation of organic pollutants in the groundwater by microorganisms, and complete the remediation of the soil and groundwater when the pollutant concentration in the groundwater at the monitoring well reaches the second groundwater remediation target value.

[0026] In some embodiments, in step S101, the temperature of the steam injected by the soil steam injection section is 100-300 DEG C, and the pressure of the injected steam is 10-100 kPa.

[0027] In some embodiments, in step S200, the temperature of the steam injected by the groundwater steam injection section is 90-100 DEG C, and the pressure of the injected steam is 10-100 kPa.

[0028] In some embodiments, in step S201, the ozone concentration generated by the ozone bubble generator is 30-60 mg / L, the ozone injection pressure is 20-100 kPa, the ozone injection flow rate is 10-25 L / min, and the diameter of the ozone bubbles is 10 nm-50 pm.

[0029] Compared with the conventional technology, the present application has at least the following beneficial effects:

[0030] The present application couples steam enhanced extraction technology, ozone micro-nano bubble in-situ chemical oxidation technology and microbial remediation technology to repair pollutants in soil and groundwater respectively, so as to reduce the pollutant concentration in soil and groundwater to a target value, and then inject ozone bubbles into the groundwater to increase the oxygen content of the groundwater and promote the growth of aerobic microorganisms, so as to continuously repair the residual microorganisms, realize pollution prevention and control of contaminated soil and groundwater, and realize soil-water integrated remediation, which has the advantages of green and sustainable development. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The repair device structure provided in one embodiment of the present application is shown in the figure; wherein 100-steam generator; 101-soil steam injection section; 102-groundwater steam injection section; 200-multi-phase extraction well; 201-soil multi-phase extraction well; 202-groundwater multi-phase extraction well; 300-ozone bubble generator; 301-ozone injection well; 400-permeable reaction barrier; 500-monitoring well; the arrow direction indicates the flow direction of the groundwater.

[0032] Figure 2 The repair method flow provided in one embodiment of the present application is shown in the figure. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to the accompanying drawings, embodiments, and examples. These embodiments and examples are for illustrative purposes only and are not intended to limit the scope of the invention. The purpose of providing these embodiments and examples is to enable a more thorough and complete understanding of the disclosure of the present invention. It should also be understood that the present invention can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various modifications or alterations without departing from the spirit of the present invention, and the equivalent forms obtained also fall within the protection scope of the present invention. Furthermore, numerous specific details are set forth in the following description to provide a fuller understanding of the present invention. It should be understood that the present invention can be implemented without one or more of these details.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0035] In this invention, "optionally," "optionally," and "optional" mean that they are optional, that is, they are selected from either "with" or "without." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent.

[0036] In this invention, the terms "first aspect," "second aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0037] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0038] All the documents mentioned in the present application are cited as references in the present application as if each document was individually cited as a reference. Unless and to the extent that the documents cited in the present application conflict with the purpose and / or technical solutions of the present application, the documents cited in the present application are cited in their entirety, for all purposes. When the present application refers to the cited documents, the definitions of the relevant technical features, terms, names, phrases, etc. in the cited documents are also cited. When the present application refers to the cited documents, the examples and preferred modes of the relevant technical features cited are also incorporated into the present application as references, but are limited to the implementation of the present application. It should be understood that when the cited content conflicts with the description in the present application, the present application is for reference or is modified according to the description in the present application.

[0039] In the conventional technology, by injecting well groups, pumping well groups and permeable reaction wall devices in the horizontal and vertical organic coupling of the contaminated soil and groundwater site, the collaborative remediation of various pollutants, the collaborative remediation of soil and water and the collaborative remediation of physical and chemical methods are realized. The main process is to inject chemical agents into the unsaturated zone soil through the injection well, to oxidize and decompose the pollutants in the contaminated site soil and groundwater, to pump out the groundwater after chemical oxidation and decomposition, to flow through the horizontally arranged permeable reaction wall, and to return the remediated groundwater to the aquifer through the injection well group. However, when using this method to remediate high-concentration organic contaminated soil and groundwater, a large amount of chemicals is consumed, and when using chemical oxidation remediation, the reaction between the chemicals and the organic pollutants may produce intermediate products with high toxicity, and the large-scale use of chemicals is easy to cause secondary pollution to the environment. The technology uses the combination of pumping and injection, which is limited by the hydrogeological conditions of the site. When the site has strong heterogeneity, it is easy to produce dominant seepage in the unsaturated zone, so that the pollutants enriched in the low-permeability medium cannot be contacted with the chemicals and are retained in large quantities, which makes it difficult to remove them by traditional hydraulic conduction, thereby causing tailing and concentration rebound problems. Since the technology is to treat the soil and groundwater at the same time, when the concentration of pollutants in the soil is high, the water flow injected will infiltrate into the aquifer, thereby causing continuous pollution of the aquifer. The present application uses steam combined with multi-phase extraction technology to realize the remediation of high-concentration contaminated soil and then the remediation of contaminated groundwater, and then uses ozone bubbles to ensure microbial self-repairing, which has the advantages of green and sustainable development.

[0040] The first aspect of the present application provides an organic contaminated site soil and water collaborative in-situ remediation device, as shown in Figure 1 The remediation device comprises a detection assembly, a steam generator 100, a multi-phase extraction well 200 and an ozone bubble generator 300.

[0041] The detection assembly comprises a soil detector and a groundwater detector, the soil detector is used to detect the concentration of pollutants in the soil, and the groundwater detector is used to detect the pollution concentration of the groundwater.

[0042] The steam generator 100 is connected with a steam injection well, the steam injection well is arranged in the upstream section of the groundwater, and the steam injection well comprises a soil steam injection section 101 and a groundwater steam injection section 102.

[0043] Along the flow direction of the groundwater, the multiphase extraction well 200 is arranged in the downstream section of the steam injection well, and the multiphase extraction well 200 comprises a soil multiphase extraction well 201 and a groundwater multiphase extraction well 202; the soil multiphase extraction well 201 is embedded in the soil and used for extracting and removing the pollutants in the soil; and the soil multiphase extraction well 201 is immersed in the groundwater and used for extracting and removing the pollutants in the groundwater.

[0044] The ozone bubble generator 300 is connected with an ozone injection well 301, and the ozone injection well 301 is immersed in the upstream section of the groundwater and used for injecting ozone bubbles into the groundwater.

[0045] In the application, the steam enhanced extraction technology is used for repairing the soil. During the soil repair process, part of the pollutants will infiltrate into the groundwater, so that the groundwater is repaired, repeated pollution is avoided, the concentration of the pollutants in the groundwater is reduced, and after the pollutants in the groundwater are removed, ozone bubbles are introduced into the groundwater, the low-concentration organic pollutants are degraded by using the ozone, the ozone bubbles exist in the groundwater for a long time and move with the groundwater, and the dissolved ozone is continuously provided to degrade the pollutants; in addition, the ozone can increase the oxygen content of the groundwater, promote the growth of aerobic microorganisms, change the aerobic microbial community in the groundwater, realize the self-repair of the microorganisms, continuously repair and remove the residual pollutants in the groundwater, and can realize the collaborative repair of the soil and the groundwater which have strong heterogeneity and high pollution concentration.

[0046] It should be noted that the upstream section of the groundwater in the application refers to the section that enters the region along the flow direction of the groundwater in the region for treating the soil and the groundwater.

[0047] It can be understood that before the soil and the groundwater are repaired, the soil and the groundwater environment of the site needs to be investigated, including the hydrogeological conditions and the pollution situation. The hydrogeological conditions include the flow direction of the groundwater, the thickness distribution of the soil layer, etc., and the pollution situation includes the types of the pollutants, the concentration of the pollutants and the range distribution of the pollutants, etc.

[0048] In some embodiments, the soil multiphase extraction well 201 is uniformly arranged in the circumferential direction of the soil steam injection section 101. Alternatively, the soil steam injection section 101 is arranged in the form of a regular polygon on the ground, that is, the soil steam injection sections 101 are respectively arranged at the vertices of the regular polygon, and the soil multiphase extraction well 201 is located at the midpoint of the regular polygon.

[0049] In some embodiments, the remediation device further comprises a permeable reactive barrier 400, which is arranged downstream of the multi-phase extraction well along the flow direction of the groundwater, and which is used to filter the groundwater to remove the pollutants.

[0050] Optionally, the permeable reactive barrier 400 is filled with an oxidizing agent. For example, the oxidizing agent comprises paraffin and persulfate slow-release material.

[0051] The present application provides a permeable reactive barrier 400 downstream of the groundwater, which can filter and remove the pollutants when the groundwater flows through the permeable reactive barrier 400, thereby preventing the further spread of the pollutants. Further, the permeable reactive barrier 400 is filled with an oxidizing agent, thereby improving the degradation effect of the pollutants.

[0052] In some embodiments, the remediation device further comprises a monitoring well 500, which is arranged downstream of the permeable reactive barrier 400, and which is used to detect the microbial colonies and the oxygen content in the groundwater.

[0053] In some embodiments, the groundwater detector comprises at least one of a pollutant concentration sensor, an oxygen concentration sensor, a pH sensor, a microbial community touch sensor, and a potential sensor.

[0054] In some embodiments, the steam generated by the steam generator 100 comprises at least one of propylene glycol, water, and air.

[0055] The steam in the present application mainly comprises water vapor, and further comprises propylene glycol and air, thereby improving the removal effect of the steam. For example, hot air can accelerate the migration of the free-phase pollutants, and propylene glycol vapor can dissolve and adsorb the pollutants in the condensed phase after condensation, thereby promoting the desorption of the pollutants from the soil.

[0056] It should be noted that the free-phase pollutants in the present application refer to the concentration value of the pollutants in the sample obtained after sampling, and the solubility of the pollutants in water and the water content of the soil. When the amount of the pollutants exceeds the maximum solubility of the pollutants in the water in the soil, it is considered that there are free-phase pollutants.

[0057] The second aspect of the present application provides a soil and groundwater remediation method for the organic contaminated site soil-water synergistic in-situ remediation device according to the first aspect, and the remediation method comprises:

[0058] After detecting the pollutant concentration in the soil and the groundwater, the steam is used to evaporate and remove the pollutants in the soil, and the soil is extracted to remove the pollutants.

[0059] After the soil pollution remediation is completed, steam is used to evaporate and remove pollutants in the groundwater, and at the same time, the groundwater is extracted to remove pollutants. After the pollutants in the groundwater are removed, ozone bubbles are introduced into the groundwater to complete the remediation of the soil and the groundwater.

[0060] In this application, the soil remediation is first carried out by using steam-enhanced extraction technology. At the steam peak, the pollutants undergo azeotropy, which promotes the evaporation of the pollutants. At the same time, the increase in temperature reduces the viscosity coefficient of the pollutants, which can promote the migration of free-phase pollutants to the multi-phase extraction well 200. Moreover, under the action of high-temperature steam, the temperature of the unsaturated zone of the soil increases, and the concentration of the pollutants decreases to the target value. The residual heat is used to promote the further degradation of the pollutants in the soil by thermophilic bacteria. In the process of water vapor displacing the pollutants, part of the heavy-phase non-aqueous fluid migrates downward into the groundwater under the action of gravity; after the pollutants in the soil are removed, steam is introduced into the groundwater to increase the temperature of the groundwater, reduce the viscosity coefficient of the free-phase pollutants, and increase the solubility of the pollutants, thereby enabling the free-phase pollutants to be removed from the groundwater through the multi-phase extraction well 200; after the steam introduction is completed, ozone micro-nano bubbles are introduced into the groundwater, and then extracted by the multi-phase extraction well 200. In this process, the oxygen content and microbial community changes in the groundwater are monitored by the monitoring well 500. When the aerobic microbial community in the groundwater increases, the introduction of ozone bubbles can be stopped. The low-concentration organic pollutants in the groundwater are further degraded by the aerobic microorganisms, and the microbial self-repairing is realized by monitoring the attenuation of the pollutants, thereby achieving the cooperative remediation of the soil and the groundwater.

[0061] It can be understood that after the groundwater is remediated by ozone bubbles, there may still be a phenomenon of rebounding increase in the concentration of organic pollutants. Therefore, a method of monitoring natural attenuation is adopted in the later stage. Through sampling and analysis, due to the change in the aerobic microbial community in the groundwater after the increase in the dissolved oxygen in the groundwater, the aerobic microorganisms further degrade the pollutants. The monitoring data of the groundwater for at least 180 days show that the concentration of the pollutants presents a steady downward trend to reach the remediation target, and it is judged that the groundwater reaches the remediation effect.

[0062] In some embodiments, the remediation device further comprises a permeable reaction barrier 400 and a monitoring well 500, as shown in Figure 2 The remediation method comprises the following steps:

[0063] S100, detecting the concentration of pollutants in the soil and the groundwater, judging whether the concentration of pollutants in the soil reaches the preset value of soil remediation, if yes, entering S101, and if not, entering S200;

[0064] S101, start the steam generator 100, inject steam into the soil steam injection section 101, evaporate and remove pollutants in the soil; open the soil multi-phase extraction well 201, extract and remove pollutants in the soil; when it is detected that the concentration of pollutants in the soil reaches the soil remediation target value, enter S200;

[0065] S200, start the steam generator 100, inject steam into the groundwater steam injection section 102, evaporate and remove pollutants in the groundwater; open the groundwater multi-phase extraction well 202, extract and remove pollutants in the groundwater; when it is detected that the concentration of pollutants in the groundwater at the monitoring well 500 reaches the first groundwater remediation target value, enter S201;

[0066] S201, start the ozone bubble generator 300, and inject ozone bubbles into the groundwater through the ozone injection well 301, and start the groundwater multi-phase extraction well 202, when it is detected that the oxygen content, microbial community and organic pollutant concentration in the groundwater at the monitoring well 500 meet the microbial remediation requirements, stop injecting ozone bubbles into the groundwater; monitor the degradation of organic pollutants in the groundwater by microorganisms, and when it is detected that the concentration of pollutants in the groundwater at the monitoring well 500 reaches the second groundwater remediation target value, complete the remediation of the soil and the groundwater.

[0067] It can be understood that the soil remediation target value, the first groundwater remediation target value and the second groundwater remediation target value in the present application can be reasonably selected according to actual remediation requirements, for example, the soil remediation target value can be determined according to GB36600 Soil Environmental Quality Construction Land Soil Risk Control Standard, and the first groundwater remediation target value and the second groundwater remediation target value can be determined according to HJ 25.6-2019 Technical Guidelines for Remediation and Risk Control of Contaminated Groundwater.

[0068] In some embodiments, in step S101, the temperature of the steam injected by the soil steam injection section 101 is 100-300°C, for example, it can be 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C or 300°C.

[0069] In some embodiments, in step S101, the pressure of the steam injected by the soil steam injection section 101 is 10-100 kPa, for example, it can be 10 kPa, 20 kPa, 30 kPa, 40 kPa, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa or 100 kPa.

[0070] In some embodiments, in step S200, the temperature of the steam injected by the groundwater steam injection section 102 is 90-100°C, for example, it can be 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, 96°C, 97°C, 98°C, 99°C or 100°C.

[0071] The present application controls the temperature of the steam injected into the groundwater to be lower than the azeotropic point of water and organic pollutants, and the temperature of the groundwater can be increased during the steam injection process. Increasing the temperature of the groundwater can reduce the viscosity coefficient of the organic pollutants and improve their migration ability, and can also avoid the high energy consumption caused by the large-scale evaporation of water.

[0072] In some embodiments, in step S200, the pressure of the steam injected by the groundwater steam injection section 102 is 10-100 kPa, for example, it can be 10 kPa, 20 kPa, 30 kPa, 40 kPa, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa or 100 kPa.

[0073] In some embodiments, in step S201, the ozone concentration generated by the ozone bubble generator 300 is 30-60 mg / L, for example, it can be 30 mg / L, 33 mg / L, 36 mg / L, 39 mg / L, 42 mg / L, 45 mg / L, 48 mg / L, 51 mg / L, 54 mg / L, 57 mg / L or 60 mg / L.

[0074] In some embodiments, in step S201, the pressure of the ozone injected by the ozone bubble generator 300 is 20-100 kPa, for example, it can be 20 kPa, 30 kPa, 40 kPa, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa or 100 kPa.

[0075] In some embodiments, in step S201, the flow rate of the ozone injected by the ozone bubble generator 300 is 10-25 L / min, for example, it can be 10 L / min, 11 L / min, 12 L / min, 13 L / min, 14 L / min, 15 L / min, 16 L / min, 17 L / min, 18 L / min, 19 L / min, 20 L / min, 21 L / min, 22 L / min, 23 L / min, 24 L / min or 25 L / min.

[0076] In some embodiments, in step S201, the diameter of the ozone bubbles generated by the ozone bubble generator 300 is 10 nm-50 μm.

[0077] The embodiments of the present application will be described in detail below with examples. It should be understood that these examples are only used to illustrate the present application and not used to limit the scope of the present application. The experimental methods in the following examples without specific conditions are preferred to refer to the guidance given in the present application, and can also be according to the experimental manual or conventional conditions in the art, or according to the conditions suggested by the manufacturer, or according to the experimental methods known in the art.

[0078] In the following examples, the organic matter in the contaminated soil includes trichloroethylene and tetrachloroethylene, wherein the concentration of trichloroethylene is 5000 mg / kg, and the concentration of tetrachloroethylene is 6000 mg / kg; the organic matter in the groundwater includes trichloroethylene and tetrachloroethylene, the concentration of trichloroethylene is 2000 mg / L, and the concentration of tetrachloroethylene is 2500 mg / L.

[0079] Example 1

[0080] S100, detecting the concentration of pollutants in the soil and groundwater, and determining whether the concentration of pollutants in the soil reaches the soil remediation preset value, wherein the soil remediation preset value of trichloroethylene is a concentration of 2.8 mg / kg, and the soil remediation preset value of tetrachloroethylene is a concentration of 53 mg / kg, if one of trichloroethylene or tetrachloroethylene reaches the soil remediation preset value, then entering S101, otherwise entering S200;

[0081] S101, starting the steam generator 100, injecting steam with a temperature of 200℃ into the soil steam injection section 101, the injection pressure is 70 kPa, and evaporating to remove pollutants in the soil; turning on the soil multi-phase extraction well 201, and extracting to remove pollutants in the soil; when it is detected that the concentration of pollutants in the soil reaches the soil remediation target value, wherein the soil remediation target value of trichloroethylene is 2.8 mg / kg, and the soil remediation target value of tetrachloroethylene is 53 mg / kg, then entering S200;

[0082] S200, starting the steam generator 100, injecting steam with a temperature of 90℃ into the groundwater steam injection section 102, the injection pressure is 70 kPa, and evaporating to remove pollutants in the groundwater; turning on the groundwater multi-phase extraction well 202, and extracting to remove pollutants in the groundwater; when it is detected that the concentration of pollutants in the groundwater reaches the first groundwater remediation target value, wherein the first groundwater remediation target value of trichloroethylene is 10 mg / L, and the first groundwater remediation target value of tetrachloroethylene is 8 mg / L, then entering S201;

[0083] S201, start the ozone bubble generator 300, and inject ozone bubbles into the groundwater through the ozone injection well 301, the ozone concentration is 40 mg / L, the pressure is 60 kPa, and the flow rate is 15 L / min, and the groundwater multiphase extraction well 202 is started at the same time, when it is detected that the concentration of trichloroethylene in the groundwater reaches 4 mg / L and the concentration of tetrachloroethylene reaches 2 mg / L, the injection of ozone bubbles into the groundwater is stopped, the ozone degradation can continuously increase the dissolved oxygen content in the groundwater, promote the degradation of organic pollutants by aerobic microorganisms, and monitor the concentration of pollutants in the groundwater; when it is detected that the concentration of pollutants in the groundwater reaches the second groundwater remediation target value, wherein the second groundwater remediation target value of trichloroethylene is 70 μg / L, and the second groundwater remediation target value of tetrachloroethylene is 40 μg / L, the remediation of soil and groundwater is completed.

[0084] Through the above examples, the steam combined with the multiphase extraction technology is used to repair the pollutants in the soil and groundwater respectively, so as to reduce the concentration of pollutants in the soil and groundwater to the target value, and then the ozone bubbles are injected into the groundwater to increase the oxygen content of the groundwater and promote the growth of aerobic microorganisms, so as to continuously repair the residual microorganisms and realize the pollution prevention and control of the contaminated soil and groundwater, the soil-water integrated remediation, and the green and sustainable development advantage.

[0085] Specifically, the permeable reaction barrier 400 is arranged downstream of the groundwater pollution first, to prevent the further expansion of the groundwater pollution range; the steam heating method combined with the multiphase extraction method is used to repair the organic contaminated soil in the unsaturated zone, the residual heat is used to promote the further degradation of the pollutants in the soil by the thermophilic bacteria in the soil; the steam heating method combined with the multiphase extraction method is used to repair the high-concentration organic contaminated groundwater, and then the ozone micro-nano bubble chemical oxidation repair technology is used to repair the low-concentration organic contaminated groundwater, the ozone degradation can increase the oxygen content of the groundwater, change the chemical conditions of the groundwater, promote the growth of aerobic microorganisms, and then the degradation of organic pollutants by microorganisms can be used to reduce the concentration of pollutants in the groundwater to the remediation target value through natural monitoring and attenuation.

[0086] In summary, the present application has the following advantages:

[0087] (1) By repairing the contaminated soil in the unsaturated zone first and then repairing the contaminated groundwater layer, the problem of continuous pollution of the groundwater layer caused by simultaneous repair of the soil and groundwater layer can be avoided;

[0088] (2) By using the steam heating combined with the multiphase extraction technology, the limitation of the heterogeneous stratum on the remediation efficiency of the pollutants can be overcome, and the remediation efficiency of the pollutants in the unsaturated zone and the groundwater aquifer can be improved;

[0089] (3) Through the soil-water synergistic multi-technology coupling, the high-efficiency green and sustainable remediation of high-concentration organic contaminated soil and groundwater can be realized.

[0090] The technical features of the above-mentioned embodiments can be combined arbitrarily, and to make the description simple, all possible combinations of the technical features in the above-mentioned embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, it should be considered that it is within the scope of the description.

[0091] The above-mentioned embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it should not be understood as the limitation of the patent scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for remediation of soil and groundwater by an organic contaminated site soil-water synergic in-situ remediation device, characterized by, The repair device comprises a detection assembly, a steam generator, a multi-phase extraction well, an ozone bubble generator, a permeable reaction barrier and a monitoring well; The detection assembly comprises a soil detector and a groundwater detector, the soil detector being configured to detect the concentration of pollutants in the soil, and the groundwater detector being configured to detect the concentration of pollutants in the groundwater; The steam generator is connected with a steam injection well, the steam injection well being arranged at an upstream section of the groundwater, and the steam injection well comprising a soil steam injection section and a groundwater steam injection section; The multi-phase extraction well is arranged at a downstream section of the steam injection well along the flow direction of the groundwater, and the multi-phase extraction well comprises a soil multi-phase extraction well and a groundwater multi-phase extraction well, the soil multi-phase extraction well being embedded in the soil for extracting and removing the pollutants in the soil, and the groundwater multi-phase extraction well being immersed in the groundwater for extracting and removing the pollutants in the groundwater; The ozone bubble generator is connected with an ozone injection well, and the ozone injection well is immersed in the upstream section of the groundwater; The permeable reaction barrier is arranged at a downstream section of the multi-phase extraction well, and the permeable reaction barrier is configured to filter the groundwater to remove the pollutants; The monitoring well is arranged at a downstream section of the permeable reaction barrier, and the monitoring well is configured to detect the microbial colonies and the oxygen content in the groundwater; The soil and groundwater remediation method of the soil-water synergistic in-situ remediation device for organic contaminated sites comprises the following steps: S100, detecting the concentration of pollutants in the soil and the groundwater, and determining whether the concentration of pollutants in the soil reaches a preset soil remediation value, if yes, proceeding to S101, and if no, proceeding to S200; S101, starting the steam generator, injecting steam into the soil steam injection section to evaporate and remove the pollutants in the soil, and starting the soil multi-phase extraction well to extract and remove the pollutants in the soil; when it is detected that the concentration of pollutants in the soil reaches a soil remediation target value, proceeding to S200; S200, starting the steam generator, injecting steam into the groundwater steam injection section to evaporate and remove the pollutants in the groundwater, and starting the groundwater multi-phase extraction well to extract and remove the pollutants in the groundwater; when it is detected that the concentration of pollutants in the groundwater at the monitoring well reaches a first groundwater remediation target value, proceeding to S201; S201, starting the ozone bubble generator, injecting ozone bubbles into the groundwater through the ozone injection well, and starting the groundwater multi-phase extraction well; when it is detected that the microbial colonies in the groundwater at the monitoring well reach a microbial remediation target value, stopping the injection of ozone bubbles into the groundwater; when it is detected that the concentration of pollutants in the groundwater at the monitoring well reaches a second groundwater remediation target value, completing the remediation of the soil and the groundwater.

2. The repair method of claim 1, wherein, The permeable reaction barrier is filled with an oxidizing agent.

3. The repair method according to claim 1 or 2, characterized in that, The groundwater detector comprises at least one of a pollutant concentration sensor, an oxygen concentration sensor, a pH sensor, a microbial colony touch sensor and a potential sensor.

4. The repair method according to claim 1 or 2, characterized in that, The steam generated by the steam generator comprises at least one of propylene glycol, water and air.

5. The repair method of claim 1 wherein, In step S101, the soil steam injection section injects steam at a temperature of 100-300 DEG C and a pressure of 10-100 kPa.

6. The repair method of claim 1 wherein, In step S200, the groundwater steam injection section injects steam at a temperature of 90-100 DEG C and a pressure of 10-100 kPa.

7. The repair method of any one of claims 1, 5 or 6, wherein, In step S201, the ozone bubble generator generates ozone at a concentration of 30-60 mg / L, injects ozone at a pressure of 20-100 kPa, and at a flow rate of 10-25 L / min, and the diameter of the ozone bubbles is 10 nm-50 microns.

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