CN117102223A - Injection, monitoring and detection integrated repairing equipment and method for heavy metal pollution site - Google Patents

Abstract

The application provides a device and a method for injecting, monitoring and detecting integrated restoration of a heavy metal polluted site, which relate to the field of polluted soil restoration and comprise the following steps: the injection device comprises a liquid storage tank and a plurality of layered injection units used for being placed in an injection well, wherein each layered injection unit comprises an upper expansion body and a lower expansion body, a flower pipe with a closed bottom end is arranged between the upper expansion body and the lower expansion body, and the top end of the flower pipe is communicated with the liquid storage tank; the real-time monitoring device comprises a plurality of temperature and humidity sensors, wherein the temperature and humidity sensors are used for being arranged in a monitoring well; the detection device is used for detecting the resistivity of the area to be repaired; the inner wall of the injection well is extruded by the two expansion bodies, so that the repairing agent can only be diffused in the stratum between the two expansion bodies when the repairing agent is injected into the flowtube, and uncontrollable migration of the repairing agent is avoided, and the diffusion range cannot be monitored.

Description

Integrated remediation equipment and methods for injection, monitoring and detection of heavy metal contaminated sites

Technical field

The invention relates to the field of contaminated soil remediation, and in particular to an integrated remediation equipment and method for injection, monitoring and detection of heavy metal contaminated sites.

Background technique

There are a large number of heavy metal contaminated sites in our country, which seriously threaten the ecological environment safety and human health. Heavy metals are the main pollutants that affect the soil environmental quality of agricultural land across the country. Pollution by cadmium, copper, lead, chromium, zinc, and nickel is relatively common, and heavy metal pollution caused by industrial industries is particularly significant. Because my country's industrialization started late, but the process is rapid, and the types of enterprises in the same industrial site change frequently, most of my country's industrial heavy metal contaminated sites are multi-metal composite contaminated sites. Due to the strong retention capacity and poor degradability of heavy metals in soil, the impact of heavy metal pollution can last for decades or even hundreds of years. At the same time, heavy metals in the soil continue to migrate under the action of groundwater seepage. The horizontal distance can reach several kilometers and the depth is nearly 100 meters. The scope of harm continues to expand; and a series of physical and chemical reactions can occur during the migration process. In the soil environment Achieve morphological transformation, making removal more difficult. In addition, heavy metals can also enter animals and plants through the soil-water-plant system, and then enter the human body indirectly or directly through the food chain and groundwater, causing chronic poisoning. Therefore, the treatment of heavy metal contaminated sites is an urgent need of society.

Commonly used remediation methods for heavy metal contaminated sites include: soil replacement and landfilling, cement kiln incineration, soil leaching, microbial phytoremediation, and in-situ injection of chemical remediation. In-situ injection chemical remediation is the most widely used among many in-situ remediation methods. It refers to injecting oxidants or reducing agents into the soil of contaminated areas to convert pollutants in the soil into non-toxic substances through oxidation or reduction. Or relatively less toxic substances to achieve the purpose of repair.

Taking the widespread lead and zinc contaminated sites in China as an example, loaded nano-zero-valent iron is injected into the underground pollution layer through in-situ injection chemical remediation method. Nano-zero-valent iron can effectively remove Pb ²⁺ and Zn in the soil. ²⁺ , removal rate up to 90%. However, in-situ injection remediation of lead and zinc contaminated sites still has the following problems:

(1) When injected into strata with complex structures and large differences, the repair agent easily penetrates along the dominant channels and cannot achieve the ideal diffusion effect;

(2) The migration of the repair agent during the injection process is uncontrollable and the diffusion range cannot be monitored;

(3) After the injection is completed, the final diffusion radius of the repair agent cannot be detected;

(4) It is impossible to achieve fixed depth, quantitative and fixed point injection of repair agent.

In response to the above problems, it is necessary to find an integrated device and method for the preparation, injection, monitoring, and detection of load-type remediation agents for heavy metal contaminated sites that is easy to operate, has low maintenance costs, and can be promoted in actual projects.

Contents of the invention

The invention provides an integrated remediation equipment and method for injection, monitoring and detection of heavy metal contaminated sites, and its purpose is to solve the disadvantages of existing in-situ injection chemical remediation.

In order to achieve the above objectives, embodiments of the present invention provide an integrated remediation equipment for injection, monitoring and detection of heavy metal contaminated sites, including:

The injection device includes a liquid storage tank and a plurality of layered injection units for placement in the injection well. The layered injection unit includes an upper expansion body and a lower expansion body. There is a gap between the upper expansion body and the lower expansion body. A flower tube with a closed bottom end, the top of the flower tube is connected with the liquid storage tank;

A real-time monitoring device, including a plurality of temperature and humidity sensors, which are used to be installed in the monitoring well;

A detection device used to detect the resistivity of the area to be repaired.

Preferably, the injection device further includes an air compressor and a gas pressure controller, the gas pressure controller is connected to the air compressor through a gas pipeline, and the gas pressure controller is provided with at least two independent controls. pressure outlets, one of which is connected to the liquid storage tank, and the remaining pressure outlets are connected to multiple expansion pipelines. Each of the expansion pipelines is connected to the upper expansion body and the lower expansion body of a layered injection unit. Control the expansion amplitude of the upper expansion body and the lower expansion body in multiple layered injection units;

An air bag is provided in the liquid storage tank, and a pressure outlet connected to the liquid storage tank controls the expansion of the air bag to discharge the injection liquid in the liquid storage tank into the flower tube.

Preferably, a pressure gauge is provided on the expansion pipeline and a flow meter is provided between the liquid storage tank and the flower tube;

The detection device includes a high-density resistivity meter and a measuring line connected to the high-density resistivity meter. Several vertical measuring line electrodes are provided on the measuring line. The measuring line is arranged at the injection well, and the measuring line is The center of the line is located at the center of the circle of the injection well, and multiple measuring lines are arranged radially;

The integrated remediation equipment for injection, monitoring, and detection of heavy metal contaminated sites also includes a central control device, which is connected with the pressure gauge, flow meter, temperature and humidity sensor, gas pressure controller, air compressor, and high-density resistivity meter. signal connection.

This application also provides a remediation method using the aforementioned integrated remediation equipment for injection, monitoring, and detection of heavy metal contaminated sites, which is characterized by including the following steps:

S1. Before remediating the contaminated site, detect the area to be repaired and obtain the initial resistivity of the area to be repaired;

S2. Excavate the injection well and monitoring well, and lower the temperature and humidity sensor and layered injection unit into the monitoring well and injection well respectively;

S3. Prepare repair agent;

S4. Adjust the expansion amplitude of the upper expansion body and the lower expansion body so that the upper expansion body and the lower expansion body are in close contact with the inner wall of the injection well respectively;

S5. Inject the repair agent into the contaminated layer between the upper expansion body and the lower expansion body through the flower tube, and obtain the changes in temperature and humidity of each monitoring well over time as well as the changes in the amount of repair agent injected over time in real time during the injection process. ;

S6. After the repair agent is injected, the area to be repaired is detected to obtain the resistivity after repair.

Preferably, in step s2, the injection well is as deep as the contaminated layer, several monitoring wells are arranged around the injection well, and the diffusion depth and diffusion radius of the monitoring wells are different.

Preferably, the repairing agent is a suspension of bentonite carrying kaolin-loaded nanoscale zero-valent iron, and the bentonite is sodium-modified bentonite.

Preferably, the mass ratio of nano-zero-valent iron in the kaolin-loaded nano-zero-valent iron is 25%-33%.

Preferably, the mass proportion of bentonite in the suspension is 3%, and the mass proportion of K-nZVI is 0.2%-0.4%.

Preferably, before step s4, an air tightness check is performed on the integrated remediation equipment for injection, monitoring, and detection of heavy metal contaminated sites.

The above solution of the present invention has the following beneficial effects:

In this application, two expansion bodies are used to inflate and squeeze the formation around the expansion body (the inner wall of the injection well), and then the expansion body is in close contact with the inner wall of the injection well, so that the repair agent can only be applied in the formation between the two expansion bodies. Diffusion avoids the uncontrollable migration of the repair agent, making the diffusion range unmonitorable.

At the same time, the two expansion bodies also limit the depth of the repair fluid in the injection well from the upper and lower directions, achieving fixed-point and positioning repair.

Other features and advantages of the present invention will be described in detail in the detailed description that follows.

Description of drawings

Figure 1 is a schematic diagram of the present invention;

Figure 2 is a schematic diagram of the assembly of the layered injection unit and injection well;

Figure 3 is a schematic diagram of the assembly of the temperature and humidity sensor and monitoring well;

Figure 4 is a schematic diagram of the location of the injection well and several monitoring wells;

Figure 5 is a schematic diagram of the steps of the repair method.

[Explanation of reference symbols]

11-liquid storage tank, 121-upper expansion body, 122-lower expansion body, 123-flower tube, 124-expansion pipeline, 125-flow meter 13-air compressor, 14-gas pressure controller,

21-Temperature and humidity sensor

31-high density resistivity meter, 32-measuring line, 33-electrode,

4-Central control device,

a-injection well, b-monitoring well,

Detailed ways

In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

As shown in Figures 1-4, embodiments of the present invention provide an integrated remediation equipment for injection, monitoring, and detection of heavy metal contaminated sites, including an injection device, a real-time monitoring device, and a monitoring device. The injection device includes a liquid storage tank 11 and a A plurality of layered injection units for inserting into the injection well a. The layered injection unit includes an upper expansion body 121 and a lower expansion body 122. The upper expansion body 121 and the lower expansion body 122 are provided with a flower tube 123 between them in the longitudinal direction. The top end of the flower tube 123 is connected with the liquid storage tank 11, and the bottom end is closed. The real-time monitoring device includes a plurality of temperature and humidity sensors 21, and the temperature and humidity sensors 21 are used to be buried in the monitoring well b. The detection device is used to detect the resistivity of the area to be repaired.

In this application, the upper expansion body 121 and the lower expansion body 122 are respectively placed into the injection well a, and through the expansion of the upper expansion body 121 and the lower expansion body 122, the inner wall of the injection well a is squeezed, so that the area to be repaired is The soil is squeezed, and when the repair agent flows from the liquid storage tank 11 into the flower tube 123, the flower tube 123 sprays the repair agent horizontally, and the repair agent flows in the stratum between the two expansion bodies, realizing the treatment of the contaminated strata in the area. Repair; By moving the position of the two expansion bodies in the vertical direction, precise control of the depth and thickness of the repair layer is achieved, which facilitates the fixed point, depth, quantitative and precise repair of heavy metal contaminated sites.

At the same time, the two expansion bodies are used to inflate and squeeze the formation around the expansion body (the inner wall of the injection well), and then the expansion body is in close contact with the inner wall of the injection well, so that the repair agent can only diffuse in the formation between the two expansion bodies, which avoids This results in the uncontrollable migration of the repair agent, making it impossible to monitor the diffusion range.

Preferably, in this embodiment, the upper expansion body 121 and the lower expansion body 122 are air bags. The air bags can be expanded and contracted by inflating and deflating, which facilitates construction and storage.

Further, the injection device also includes an air compressor 13 and a gas pressure controller 14. The air compressor 13 and the gas pressure controller 14 are connected through a gas pipeline. The gas pressure controller 14 is provided with at least two independently controlled pressures. One of the pressure outlets is connected to the liquid storage tank 11, and the other pressure outlets are connected to a plurality of expansion pipelines 124. Each expansion pipeline 124 is connected to the upper expansion body 121 and the lower expansion body 122 of a layer injection unit respectively. The gas pressure control ensures full extrusion between the two expansion bodies and the inner wall of the injection well a by controlling the amount of inflation input into the two expansion bodies.

The aforementioned liquid storage tank 11 is provided with another air bag, which is located at the bottom of the liquid storage tank 11 , and the repair agent is filled in the liquid storage tank 11 . Under the extrusion of the air bag, the repair agent flows into the flower tube 123 from the pipe above the liquid storage tank 11, and is injected into the formation through the flower tube 123. Since the repair agent is a suspension, it is easy to precipitate. Therefore, when the gas pressure controller 14 controls the expansion of the air bag, the repair agent can be stirred, which helps to alleviate the precipitation phenomenon and improve the repair effect.

Furthermore, the top of the liquid storage tank 11 is also provided with a charging valve and an exhaust hole. When loading, the exhaust hole is in an open state. The bottom of the liquid storage tank 11 is provided with a connecting flange to facilitate disassembly of the liquid storage tank 11 for cleaning.

Preferably, a pressure gauge and an expansion valve are provided on the expansion pipeline 124. The pressure gauge is used to detect the gas pressure of the two expansion bodies to ensure that the two expansion bodies are in full contact with the injection well a. A flow meter 125, a flow valve and a flow pressure meter are provided between the liquid storage tank 11 and the flower tube 123. The flow meter 125 is used to record the instantaneous flow rate and cumulative flow rate of the repair agent injected. The flow valve is used to control the connection between the liquid storage tank 11 and the flower tube 123. The flow pressure meter is closer to the side of the liquid storage tank 11 than the flow valve.

The aforementioned detection device includes a high-density resistivity meter 31 and a measuring line 32, where the measuring line 32 is signal-connected to the high-density resistivity meter 31 and the measuring line 32. The measuring line 32 is used to be set at the injection well a and ensure that the measuring line The center of 32 is located at the center of injection well a. The measuring line 32 is also provided with a plurality of electrodes 33 perpendicular to the measuring line 32. The electrodes 33 are inserted into the soil layer of the area to be repaired during detection.

Preferably, multiple survey lines 32 are provided, and the plurality of survey lines 32 are arranged radially from the center of the injection well a.

Preferably, the cross section of the injection well a is circular.

The integrated remediation equipment for injection, monitoring and detection of heavy metal contaminated sites also includes a central control device 4, a pressure gauge, a flow meter 125, a temperature and humidity sensor 21, a gas pressure controller 14, an air compressor 13 and a high-density resistor Rate meter 31 signal connection.

The central control device 4 can control the power of each pressure outlet of the gas pressure sensor, and record and draw the injection pressure change curve with time.

The central control device 4 can also record the instantaneous flow rate and accumulated flow rate through the flow meter 125 and draw a flow curve over time.

Preferably, the diameter of the flower tube 123 is smaller than the diameter of the two expansion bodies before expansion, and the spray apertures on the sides of the flower tube 123 remain consistent and evenly distributed.

The aforementioned temperature and humidity sensor 21 includes a probe and a wireless signal transmitter connected to the probe signal. The wireless signal transmitter receives the signal from the probe and transmits the signal to the central control device 4 . The probe is buried in the monitoring well b.

Figure 1-4 combined with Figure 5, this application also provides a repair method, using the aforementioned repair equipment, including the following steps:

S1. Before remediating the contaminated site, detect the area to be repaired and obtain the initial resistivity of the area to be repaired. The initial resistivity is obtained through a high-density resistivity meter 31 and measuring lines 32.

S2. Excavate the injection well a and the monitoring well b, and the injection well a and the monitoring well b are deep into the contaminated layer. Several monitoring wells b are arranged around the injection well a, and the distance between the monitoring well b and the injection well a is different. The monitoring wells The depth of b is different, and the temperature and humidity sensor 21 is buried in the monitoring well b to realize the monitoring of various positions in the three-dimensional space around the injection well a.

Lower the layered injection unit into injection well a.

S3. Prepare the repair agent. The repairing agent is a suspension of bentonite carrying kaolin loaded with nanometer zero-valent iron, and the bentonite is sodium-modified bentonite.

Among conventional repairing agents, kaolin-loaded nano-zero-valent iron is often mixed into water to form a suspension as a repair agent. However, the repair effect of the suspension prepared by water and kaolin-loaded nano-zero-valent iron is poor. For this reason, this application uses Bentonite suspension replaces water, and bentonite suspension is mixed with kaolin-loaded nano zero-valent iron to form the repair agent of the present application, which has a better repair effect.

Check the air tightness of the integrated remediation equipment for injection, monitoring and detection of heavy metal contaminated sites. The detection of air tightness includes two aspects. On the one hand, it is to detect the air tightness of the gas circuit, and on the other hand, it is to check the air tightness of the fluid pipeline. After the detection device is assembled, fill the liquid storage tank 11 with clean water, turn on the air compressor 13, inflate the two expansion bodies until the expansion body and the injection well a are tightly squeezed, close the expansion valve, and observe The value of the pressure gauge changes. After a certain period of time, the value of the pressure gauge remains constant, which proves that the air tightness of the air circuit is intact. Further, maintain the current pressure of the expansion body and close the flow valve. After a period of time, the value of the flow pressure gauge remains constant, which proves that the air tightness of the fluid pipeline is intact.

After the repair agent is configured, the repair agent is injected into the liquid storage tank 11 for use.

S4. Adjust the expansion amplitude of the upper expansion body 121 and the lower expansion body 122 so that the upper expansion body 121 and the lower expansion body 122 are in close contact with the inner wall of the injection well a, and exert a squeezing force on the inner wall of the injection well a, and Maintain the current squeeze force.

S5. Inject the repair agent into the contaminated layer between the two expansion bodies through the flower tube 123, and obtain the changes in temperature and humidity over time in each monitoring well b and the changes in the injection amount of the repair agent over time in real time during the injection process. .

S6. After the repair agent is injected, the area to be repaired is detected to obtain the resistivity after repair.

At 0h, 2h, 4h, 8h, 24h, 48h, 120h and 240h after the injection is completed, the measuring line 32 is placed above the injection well a, and the electrode 33 is inserted into the soil, and the conductivity of the repair area is detected and compared with Compare the detection data before site restoration and analyze the diffusion and migration of loaded nano zero-valent iron.

Regularly take groundwater samples from the maximum impact range of injection well a and detect the concentrations of lead ions and zinc ions. Combine monitoring data (pressure, flow, temperature and humidity changes) and detection data to analyze and evaluate the repair effect.

In this application, the mass ratio of nano-zero-valent iron in kaolin-loaded nano-zero-valent iron is 25%-33%. The mass proportion of bentonite in the suspension is 3%, and the mass proportion of K-nZVI is 0.2%-0.4%.

Example 1

In Example 1, the mass ratio of bentonite to water was 0%, 1%, 3%, and 5%, and the mass ratio of kaolin loaded nano zero-valent iron (K-nZVI) to water was 0.1%, 0.2%, and 0.4%. Restorative. Weigh the corresponding masses of water, bentonite and K-nZVI according to the test plan; add the bentonite to the water several times, stir the suspension at high speed for 5 minutes; let the suspension stand for 24 hours to hydrate; finally add the weighed K-nZVI and The bentonite suspension is thoroughly mixed and stirred at high speed for 3 minutes. The bentonite suspension carrying the K-nZVI repair agent is prepared, and then the absorbance test is performed. The stability of the repair agent is evaluated based on the relative absorbance (absorbance at a certain time/initial absorbance) of the repair agent after it has been left standing for 4 hours. The greater the relative absorbance, the more stable the repair agent system is. The specific test plan and results are shown in Table 1.

Table 1 Relative absorbance of repair agents with different ratios after 4 hours

Note: The ratio of bentonite to water is zero, which means no bentonite is added. The ratio of bentonite to water and the ratio of K-nZVI to water are independent of each other and do not affect each other.

It can be seen from Table 1 that without the addition of bentonite, K-nZVI settles quickly in water, and the absorbance drops to 30% of the initial value after about 4 hours. Through comparison, it was found that even a small amount of bentonite can effectively improve the dispersion and stability of K-nZVI particles, and the greater the amount of bentonite, the better the dispersion and stability of K-nZVI. According to Table 1, the bentonite content in the repair agent should be greater than or equal to 3%.

Example 2:

A rotational viscometer was used to test the viscosity of repair agents with different ratios. Viscosity is an important indicator to characterize the rheology of a repair agent. The lower the viscosity, the stronger the injectability. The specific test plan and results are shown in Table 2.

Table 2 Viscosity values of repair agents with different ratios

It can be seen from Table 2 that the increase in the content of bentonite and K-nZVI will lead to an increase in the viscosity of the repair agent. The influence of bentonite on the viscosity of the repair agent is more significant, and the influence of K-nZVI on the viscosity of the repair agent is related to the dosage of bentonite. When the bentonite content is 5%, as the K-nZVI content increases, the viscosity of the repair agent increases twice. When the bentonite content is 1% and 3%, as the K-nZVI content increases, the viscosity of the repair agent increases. The increase is gentle, indicating that K-nZVI has a greater impact on the viscosity of the repair agent with a higher bentonite content. In addition, when the bentonite content is 5%, the repair agent clay increases suddenly, and the viscosity increases faster with the increase in K-nZVI content. In summary, the bentonite content in the repair agent should be 3%, and the K-nZVI content should be 0.4%.

Example 3:

Prepare a 1000mg/L solution of heavy metal lead and zinc ions, and conduct a repair test according to bentonite: water: 3%, K-nZVI: water: 0.4%. The ratios of nanometer zero-valent iron (nZVI) and kaolin (Kaolin) in K-nZVI used are 1:0, 1:4, 1:3, 1:2, 2:3 respectively, and a group of only doped Controlled experiments with bentonite clay. The pH of the test solution was not adjusted. The specific test plan and results are shown in Table 3.

Table 3 Heavy metal lead and zinc ion removal rates ((Re)

As can be seen from Table 3, compared with pure bentonite and nZVI, K-nZVI has a significant removal effect on heavy metal lead and zinc ions. Comparing the test results with nZVI and Kaolin ratios of 1:0, 1:4, 1:3, 1:2, and 2:3, it was found that the ratios of nZVI and Kaolin in kaolin-loaded nano zero-valent iron are 1:3 and 1 :2, the removal rate of lead and zinc ions is higher. When the mass ratio of the two is 1:2, the removal rates are the highest, 94.4% and 92.4% respectively. In summary, the mass proportion of nano-zero-valent iron in kaolin-loaded nano-zero-valent iron should be 25% to 33%.

This application provides an integrated remediation equipment and method for injecting, monitoring, and detecting heavy metal contaminated sites, 1) using an injection device, a monitoring device, a detection device, and a control device to automate the injection, monitoring, monitoring, and remediation, and The pressure, flow rate, and formation temperature and humidity changes during the agent injection process are stored and visualized. The injection situation can be remotely monitored 24 hours a day, and the injection parameters can be adjusted according to the actual injection situation. Compared with traditional repair agent injection equipment, the integration of this application Higher, more comprehensive functions, remote control and injection-monitoring-detection integration.

2) The integrated remediation equipment for heavy metal contaminated site injection, monitoring and detection provided by this application can achieve precise control of the depth and thickness of the remediation area through the combined use of flower tube 123 and two expansion bodies, and improve the effectiveness of the remediation agent in the remediation process. The controllability within the area facilitates rapid post-construction detection and enables the fixed-point, quantitative, depth-determined and precise restoration of medium-metal contaminated sites.

3) This application also provides a ratio of repair agents, which uses bentonite suspension to have good carrying capacity, heavy metal adsorption and reduction properties to configure the repair agent, improve the stability of the repair agent system, and have a smaller viscosity value, reducing the resistance during the repair injection process, can effectively increase the migration distance of nano-zero-valent iron, reduce the deposition of nano-zero-valent iron in the soil layer, increase the diffusion radius of nano-zero-valent iron in contaminated strata, and to enhance transmission.

4) Bentonite suspension carries kaolin to load nano zero-valent iron. Sodium-modified bentonite suspension is used to carry kaolin to load nano-zero-valent iron. Kaolin-loaded nano-zero-valent iron can effectively solve the problem that nano-zero-valent iron is easy to agglomerate and oxidize. , preparing a sodium-modified bentonite suspension to carry nano-zero-valent iron can reduce the sedimentation of nano-zero-valent iron in the repair agent system. In addition, the sodium-modified bentonite has strong heavy metal adsorption, and the kaolin-loaded nano-zero-valent iron has strong reducing properties. Therefore, compared with the traditional nano-zero-valent iron repair agent, the method provided by the invention has a higher heavy metal removal rate. The remediation effect of contaminated sites is better.

Compared with other nano zero-valent iron reinforced transmission materials, the materials used in the present invention, sodium-modified bentonite and kaolin, are cheap and easy to obtain; compared with traditional injection devices, the device of the present invention is highly integrated, has simple operation methods, and can be remotely controlled; enhanced While improving the remediation effect, it also saves the cost of remediation of contaminated sites.

The above is the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications can also be made. should be regarded as the protection scope of the present invention.

Claims (9)

1. Injection, monitoring and detection integrated repair equipment for heavy metal contaminated sites, which is characterized by comprising:

the injection device comprises a liquid storage tank (11) and a plurality of layered injection units used for being placed in an injection well (a), wherein each layered injection unit comprises an upper expansion body (121) and a lower expansion body (122), a flower pipe (123) with a closed bottom end is arranged between the upper expansion body (121) and the lower expansion body (122), and the top end of the flower pipe (123) is communicated with the liquid storage tank (11);

the real-time monitoring device comprises a plurality of temperature and humidity sensors (21), wherein the temperature and humidity sensors (21) are used for being arranged in a monitoring well (b);

and the detection device is used for detecting the resistivity of the area to be repaired.

2. The integrated repair device for heavy metal contaminated site injection, monitoring and detection according to claim 1, wherein: the injection device further comprises an air compressor (13) and a gas pressure controller (14), wherein the gas pressure controller (14) is communicated with the air compressor (13) through a gas pipeline, at least two independently controlled pressure outlets are arranged on the gas pressure controller (14), one pressure outlet is communicated with the liquid storage tank (11), a plurality of expansion pipelines (124) are respectively communicated with the rest pressure outlets, and each expansion pipeline (124) is respectively communicated with an upper expansion body (121) and a lower expansion body (122) of one layered injection unit so as to control the expansion amplitude of the upper expansion body (121) and the lower expansion body (122) in the layered injection units;

an air bag is arranged in the liquid storage tank (11), and a pressure outlet communicated with the liquid storage tank (11) discharges injection liquid in the liquid storage tank (11) into the flower pipe (123) through controlling the expansion of the air bag.

3. The integrated repair device for heavy metal contaminated site injection, monitoring and detection according to claim 1, wherein: a pressure gauge is arranged on the expansion pipeline (124), and a flowmeter (125) is arranged between the liquid storage tank (11) and the flower pipe (123);

the detection device comprises a high-density resistivity meter (31) and a measuring line (32) connected with the high-density resistivity meter (31), wherein a plurality of electrodes (33) of vertical measuring lines (32) are arranged on the measuring line (32), the measuring line (32) is arranged at the injection well (a), the center of the measuring line (32) is positioned at the center of the injection well (a), and a plurality of measuring lines (32) are radially arranged;

the integrated repairing equipment for heavy metal pollution site injection, monitoring and detection further comprises a central control device (4), wherein the central control device (4) is in signal connection with the pressure gauge, the flowmeter (125), the temperature and humidity sensor (21), the gas pressure controller (14), the air compressor (13) and the high-density resistivity meter (31).

4. A repair method adopting the integrated repair equipment for heavy metal pollution site injection, monitoring and detection as claimed in claim 3, which is characterized by comprising the following steps:

s1, before repairing a polluted site, detecting a region to be repaired, and acquiring the initial resistivity of the region to be repaired;

s2, excavating an injection well (a) and a monitoring well (b), and respectively lowering a temperature and humidity sensor (21) and a layered injection unit into the monitoring well (b) and the injection well (a);

s3, preparing a repairing agent;

s4, adjusting the expansion amplitude of the upper expansion body (121) and the lower expansion body (122) so that the upper expansion body (121) and the lower expansion body (122) are respectively in close contact with the inner wall of the injection well (a);

s5, injecting a repairing agent into a pollution layer between the upper expansion body (121) and the lower expansion body (122) through a flowtube (123), and acquiring the change of the temperature and the humidity of each monitoring well (b) along with the time and the change of the injection quantity of the repairing agent along with the time in real time in the injection process;

s6, after the repairing agent is injected, detecting the area to be repaired to obtain the resistivity after the repairing.

5. The repair method according to claim 4, wherein: in step s2, the injection well (a) is deep to the contaminated layer, several monitoring wells (b) are laid around the injection well (a), and the diffusion depth and diffusion radius of the monitoring wells (b) are different.

6. The repair method according to claim 5, wherein: the repairing agent is bentonite suspension carrying kaolin loaded with nano zero-valent iron, and the bentonite is sodium modified bentonite.

7. The repair method according to claim 6, wherein: the mass ratio of the nano zero-valent iron in the kaolin loaded nano zero-valent iron is 25% -33%.

8. The repair method according to claim 6, wherein: the mass ratio of bentonite in the suspension is 3%, and the mass ratio of K-nZVI is 0.2% -0.4%.

9. The repair method according to claim 4, wherein: before step s4, the gas tightness inspection is carried out on the integrated repairing equipment for injecting, monitoring and detecting the heavy metal polluted site.