CN115180765B - Underground water circulation well temperature control method, system and device - Google Patents

Abstract

The invention relates to a temperature control system of a groundwater circulation well, which comprises a circulation well body for collecting and treating groundwater with organic pollutants, first purifying equipment for separating the organic pollutants and the groundwater in the circulation well body, and second purifying equipment for treating the separated organic pollutants to remove harm. The first purifying device comprises an aeration device for driving the hydraulic circulation of the circulating well and a temperature control device for heating the underground water in the circulating well to promote the volatilization of organic pollutants in the underground water, and the temperature control device is arranged between an upper screen pipe and a lower screen pipe in the containing space in the circulating well to heat the underground water in the circulating well. According to the invention, the volatilization rate of volatile/semi-volatile organic pollutants in underground water can be improved through aeration and heating, the separation of the pollutants from underground water is promoted, the volatilized organic pollutants are treated through the purification equipment, and the harm of the organic pollutants is reduced.

Description

A groundwater circulation well temperature control method, system and device

Technical field

The present invention relates to the technical field of energy conservation and environmental protection, and in particular to a groundwater circulation well temperature control method, system and device.

Background technique

Semi-volatile organic compounds (SVOCs) such as aniline and polycyclic aromatic hydrocarbons, as important chemical raw materials, were manufactured and used in large quantities during the period of rapid industrial development. Subsequently, a large number of pollutant leakage accidents occurred, such as due to unreasonable storage, Broken oil pipelines and leaking oil storage tanks cause such semi-volatile organic compounds to enter surface water. These pollutants can easily attach to colloidal organic matter in solution, which enhances their solubility and ability to migrate to groundwater. In addition, this type of organic pollutants are very toxic to the blood and nerves and can cause poisoning through absorption from the panel or through the respiratory tract. In the process of evolution, such chemicals will migrate to other waters along with underground runoff, and then come into contact with the human body through irrigation or drinking, causing widespread impacts.

Currently, the main methods for remediation of semi-volatile groundwater pollution include ex-situ remediation technology and in-situ remediation technology. Ex-situ remediation technology mainly includes the steps of extraction and treatment, pumping groundwater to the ground for remediation treatment; in-situ remediation technology includes in-situ chemical oxidation, permeable reaction barrier and other technologies. The main problems in the use of in-situ chemical oxidation technology are: the uniform contact reaction between the injected agent and the pollutants is difficult to control, and the treatment effect is highly dependent on the accurate characterization of the site and the limitations of the design of the injected agent delivery system. In addition, the high consumption of oxidants by other organic components in soil and groundwater will also lead to low utilization efficiency of chemicals. The repair method of the permeable reaction barrier may cause blockage during use, which will affect the implementation effect of the PRB project. Therefore, it is necessary to ensure that the reaction medium has sufficient water permeability.

As another option for in-situ remediation, groundwater circulation well technology drives groundwater to form a circular flow inside and outside the well, carrying organic pollutants dissolved in the groundwater into the inner well. It can remove semi-volatile pollutants under the action of aeration and stripping. Organic pollutant removal. Circulation well equipment has the advantages of simple operation and maintenance, can effectively accelerate the vertical circulation of water flow, is easy to match with other remediation technologies, can directly remove pollutants and control the diffusion of pollutants at the same time, and has a wide range of application prospects in the actual site remediation process. .

The prior art CN103864263B provides a circulating well system for removing volatile organic compounds in groundwater. The system includes: an outer well, an inner well, a gas injection system, a gas extraction system and a chemical spray system. The inner well is equipped with In the outer well, the gas injection system is used to inject gas into the inner well water for aeration. After aeration, part of the gas doped with organic pollutants is extracted by the gas extraction system and then The activated carbon adsorption device adsorbs and discharges, and the other part enters the outer well, and the chemical spray system is used to spray chemical liquid into the outer well.

Separate circulating well technology has a good remediation effect on volatile organic pollutants such as BTEX, but has poor removal efficiency for some semi-volatile organic pollutants with poor volatility and low solubility (such as aniline, polycyclic aromatic hydrocarbons, and chlorobenzene). The reason is that semi-volatile organic pollutants have poor volatility and are difficult to enter from the water phase into the gas phase, and the aeration and stripping effect in the well is not obvious; secondly, semi-volatile organic pollutants The solubility is small, and the mass transfer efficiency of pollutants from the medium to groundwater is low, resulting in an insignificant remediation effect of the circulation well.

Site in-situ thermal remediation technology has the same remediation mechanism as circulating wells, both of which use the volatility of pollutants to separate them from groundwater. Site in-situ thermal remediation technology significantly increases the temperature of the site soil and groundwater by heating the contaminated area in situ, thereby accelerating the volatilization of organic pollutants in the contaminated area, the separation of organic pollutants from soil organic matter, or increasing the flow of pollutants underground. The pollutants after volatilization or separation are then processed on the ground through extraction. Site in-situ thermal remediation technology can significantly accelerate the analysis of pollutants in soil and aquifer media and enhance the volatilization of pollutants. Combining site in-situ thermal remediation technology with circulation wells can significantly improve the remediation effect of circulation wells on semi-volatile pollutants.

The prior art CN202591210U provides a device for treating contaminated soil using in-situ thermally enhanced combined soil/groundwater gas phase extraction technology. The device is: forming a soil opening in the contaminated soil area as a heating well, placing a heater component in the heating well, forming at least one soil opening in the center of the heating well as an extraction well, deploying a vacuum system in the extraction well, and connecting the extraction well There is a vacuum tube; the heater component is heated by the power provided by the surface power supply system, and then the heater component transfers its heat to the adjacent soil. The exhaust gas generated by the heating is extracted to the ground by the vacuum system, and collected by the vacuum tube. The collected exhaust gas is transmitted to the pollutant There are surface collection and treatment facilities for materials, and the discharge meets the standards after treatment.

The treatment device promotes the desorption of volatile/semi-volatile organic substances in soil/groundwater from the soil and aquifer media to form tail gas through heating. The tail gas is then extracted to the ground by a vacuum system for collection and processing. The processed gas or The liquid is then re-injected into the soil through a circulation pump to speed up the analysis of pollutants. This method decomposes the pollutants in the soil layer by heating, and at the same time, there is a risk that the pollutants will volatilize from the surface to the air environment. To reduce such risks, it is necessary to lay an insulation layer on the ground surface, which requires a large construction area. Due to the static pressure of groundwater and the pressure of soil capillaries, it is difficult to form a gas channel, prone to gas short circuits, and the pollutant removal efficiency is limited; and the device The heating layer is set in the soil layer and is mainly used to treat pollutants in the soil. The well maintains negative pressure for a long time and it is difficult for groundwater to circulate in a small area. It is not suitable for treating semi-volatile organic pollutants in groundwater.

In addition, on the one hand, there are differences in the understanding of those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making the present invention, but due to space limitations, all details and contents are not listed in detail. However, this is by no means The present invention does not have these features of the prior art. On the contrary, the present invention already has all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art.

Contents of the invention

In view of the shortcomings of the existing technology, the present invention provides a groundwater circulation well temperature control system, which includes: a lower screen tube for groundwater to flow in and an upper layer screen tube for groundwater to flow out; and a system for collecting groundwater with organic pollutants. The circulating well body for processing, the first purification equipment used to aerate and heat the circulating well body to efficiently separate organic pollutants and groundwater, and the second purification equipment used to process the separated organic pollutants to eliminate hazards Purification equipment. The first purification device is disposed in the liquid environment inside the circulation well, and the second purification device is disposed outside the circulation well and communicates with the circulation well to obtain gas containing organic pollutants.

This setting is conducive to strengthening the separation of semi-volatile organic pollutants in groundwater by collecting groundwater within a certain range into the circulation well and then centrally raising the temperature. That is to say, it can avoid large-scale heating of traditional thermal repair and reduce the risk of pollutants overflowing into the atmospheric environment. At the same time, focusing on heating and separation in the circulation well can effectively reduce energy consumption, and the repaired groundwater returns to the formation again through the upper screen tube. In this method, the pollutants are treated while maintaining the normal flow of groundwater, which has little disturbance to the flow of regional groundwater. At the same time, the centralized collection of organic pollutant waste gas is more conducive to centralized treatment.

According to a preferred embodiment, the first purification equipment includes a temperature control device for heating the groundwater in the circulation well body to promote the volatilization of organic pollutants in the groundwater and a temperature control device for injecting air into the groundwater in the circulation well body. An aeration device that accelerates molecular activity in groundwater. The temperature control device is installed between the upper screen tube and the lower screen tube in the internal accommodation space of the circulation well body to heat the groundwater in the circulation well body.

This setting method is beneficial: aeration of groundwater can promote molecular movement in groundwater and promote the separation of semi-volatile organic pollutants in groundwater from groundwater; at the same time, heating and warming can further promote molecular movement in groundwater, and molecules in groundwater While moving, the heated heat is transferred to the surrounding molecules; the groundwater gradually rises from the lower screen tube to contact the temperature control device and is continuously heated. The volatilization rate constant of semi-volatile organic pollutants increases exponentially with the change of temperature. It gradually separates from the groundwater and enters the gas phase, and is separated during the circulation flow process.

According to a preferred embodiment, the second purification equipment includes a vacuum extraction device for extracting gas with organic pollutants from the circulation well body and a gas purification device for treating organic pollutants. The vacuum The extraction device extracts waste gas through the exhaust pipe arranged above the upper screen tube.

According to a preferred embodiment, the temperature control device includes a temperature control unit, a temperature rising unit and a temperature monitoring unit. The temperature monitoring unit is arranged close to the upper screen tube and is used to monitor the temperature that will be output from the circulation well after heating. Groundwater temperature.

The benefit of this setting is that by using the monitored temperature of the groundwater output from the circulating well after continuous heating as a feedback condition to adjust the heating temperature of the heating unit, the actual results can be directly fed back to the source of the temperature for adjustment. It is not affected by the intermediate process, especially as the upper marginal water body, which is in close contact with the gas phase and the well body, and has a large temperature difference with the surroundings. When the heating temperature is low, it is difficult to ensure that the temperature reaches the volatilization requirements, and will be monitored The unit is set here, and when the temperature of the edge water reaches the requirements, the temperature of the water in the circulation well can meet the volatilization requirements of semi-volatile organic pollutants.

According to a preferred embodiment, the heating temperature of the heating unit is 40 to 80°C.

According to a preferred embodiment, an upper sealing cover and a lower sealing cover for preventing gases containing organic pollutants from entering the atmosphere and soil are provided at one end of the circulation well body close to the earth's surface and one end away from the earth's surface.

On the other hand, the present invention also provides a method for removing organic pollutants in groundwater, which includes the following steps:

Utilize the aeration driving effect in the circulation well to allow the groundwater in the formation to enter the well through the filter set in the well wall;

Use the first purification equipment located in the well to purify the groundwater entering the well and separate the semi-volatile substances in the groundwater;

The second purification equipment located outside the well is used to collect the semi-volatile substances and process the harmful substances therein.

The method is applicable to a temperature-controlled circulating well system for removing organic pollutants from groundwater.

According to a preferred implementation, when the organic pollutants in the groundwater are volatile organic compounds (such as benzene, toluene, etc.), the parameters of the first purification equipment and the second purification equipment are set to: set the repair temperature to 40-60°C ℃, the aeration flow rate is set to 50m ³ /h, and the extraction flow rate is set to 50m ³ /h.

According to a preferred embodiment, when the organic pollutants in the groundwater are semi-volatile organic compounds (such as aniline, organochlorine pesticides, polycyclic aromatic hydrocarbons, etc.), the parameters of the first purification equipment and the second purification equipment are set to: restore The temperature is set to 60 to 80°C, the aeration flow rate is set to 30m ³ /h, and the extraction flow rate is set to 30m ³ /h.

According to a preferred embodiment, when the organic pollutants in the groundwater are semi-volatile and volatile organic mixtures, the parameters of the first purification equipment and the second purification equipment are set in a step-by-step manner. First, the repair temperature is set. The temperature is 40~60℃, the aeration flow is set to 40m ³ /h, and the extraction flow is set to 40m ³ /h. When the removal rate of volatile pollutants exceeds 80%, the repair temperature is increased to 60~80℃, and the half-time speed is accelerated. Removal of volatile contaminants.

The benefit of this setting is that different treatment parameter combinations are adopted based on different volatile organic pollutants in groundwater. When treating low-volatile organic pollutants, a larger heating temperature and a smaller aeration flow can be adopted to increase the temperature. At the same time, it enhances the residence time of contaminated groundwater in the well and enhances the volatilization rate; when dealing with highly volatile organic pollutants, a smaller heating temperature and a larger aeration flow can be adopted, which can effectively remove pollutants while expanding the repair radius. .

Description of the drawings

Figure 1 is a schematic diagram of a simplified module connection relationship of the overall structure of a preferred embodiment provided by the present invention;

Figure 2 is a simplified schematic diagram of a preferred embodiment of the simulation experiment provided by the present invention;

Figure 3 is a concentration distribution diagram of the pollutant purification effect of the simulation experiment provided by the present invention.

List of reference signs

1: Upper sealing cover; 2: Exhaust pipe; 3: Upper screen tube; 4: Middle wall tube; 5: Lower screen tube; 6: Lower sealing cover; 7: Heating unit; 8: Fixed unit; 9: Temperature monitoring Unit; 10: Aeration head; 11: Air pump; 12: First flow meter; 13: First valve; 14: Aeration pipe; 15: Electrical wire; 16: Temperature sensing line; 17: Temperature control unit; 18: The second valve; 19: The second flow meter; 20: The first extraction pipe; 21: Vacuum pump; 22: The third valve; 23: The second extraction pipe; 24: Gas purification device.

Detailed ways

Detailed description will be given below with reference to Figures 1, 2 and 3.

Example 1

This embodiment provides a groundwater circulation well temperature control device, which mainly includes: a circulation well body, a temperature control device, an aeration device, a vacuum extraction device, and a gas purification system.

The circulation well body includes side walls and an internal accommodation space, as shown in Figure 1. A lower screen pipe 5 for allowing groundwater to flow into the well is provided on the side wall of the end facing away from the earth's surface. An upper screen pipe 3 for groundwater to flow out from the well into the formation is provided on the side wall of one end of the circulation well body close to the surface. A water-impermeable intermediate wall tube 4 is provided between the upper screen tube 3 and the lower screen tube 5 . An upper sealing cover 1 is provided at one end of the circulation well body close to the surface. A lower sealing cover 6 is provided at one end of the circulation well body away from the earth's surface. The sealing cover is used to seal the space inside the well to prevent organic pollutants in the well from leaking to the surface or underground. Preferably, the size of the sealing cover is consistent with the outer diameter of the well pipe, so that no extra construction area is added during construction, which facilitates construction. When used, the contaminated groundwater enters the circulation well from the lower screen tube 5 based on the pressure of the groundwater; after being treated in the circulation well, the treated groundwater passes through the upper screen tube 3 based on the pressure difference between the upper and lower water levels outside the well. flow back into the groundwater.

The temperature control device is arranged in the accommodation space inside the circulation well body and includes: a temperature control unit 17, a temperature rising unit 7 and a temperature monitoring unit 9. The heating unit 7 is arranged in the circulation well and is used to heat the groundwater entering the internal accommodation space of the circulation well. The temperature control unit 17 is installed outside the circulation well, is connected to the temperature increasing unit 7 through data, and controls the working state of the temperature increasing unit 7 through signals. For example, the temperature raising unit 7 and the temperature control unit 17 are connected through electrical conductors 15 . The temperature increasing unit 7 is installed in the circulation well and used to monitor the groundwater temperature in the circulation well. The temperature monitoring unit 9 is connected with the temperature control unit 17 through data, and is used to provide the temperature control unit 17 with a temperature reference value for adjusting the control signal. For example, the temperature monitoring unit 9 and the temperature control unit 17 are connected through a temperature sensing line 16 . Preferably, the temperature monitoring unit 9 is a thermocouple, for example. Preferably, the temperature of the heating unit 7 is specifically determined based on parameters such as the thickness of the aquifer and the nature of the pollutants. Preferably, the heating temperature of the water flow in the circulation well is generally 40 to 80°C. Preferably, the heating unit 7 is stably fixed in the circulation well body through the fixing unit 8 to prevent it from being disturbed by the groundwater flow and affecting its normal operation. Preferably, the heating unit 7 is fixed on the well section of the intermediate wall pipe 4 between the upper screen tube 3 and the lower screen tube 5 to heat the water flow in the circulation well. Preferably, the fixing unit 8 can be a card holder, for example. The edges of the two card holders are clamped on the inner wall of the circulation well, and the heating unit 7 is clamped between the two cards. A slot for fixing the heating unit 7 is provided in the middle of the two card trays. As shown in Figure 1 , the fixing unit 8 includes an accommodation space for accommodating the heating unit 7 and fixing parts arranged around the accommodation space for connection with the well body. There are four fixing parts, which are arranged symmetrically with each other to provide stable receiving. force.

The aeration device includes: an air pump 11, a first flow meter 12, a first valve 13, an aeration pipe 14 and an aeration head 10. The air pump 11 is connected to the first flow meter 12 and the aeration head 10 in sequence, and the aeration flow rate is controlled through the first flow meter 12 . Preferably, the aeration flow rate is determined according to the thickness of the aquifer and the spacing between the upper screen tube 3 and the lower screen tube 5 . The first valve 13 is provided on the aeration pipe 14 for regulating the aeration flow. The aeration head 10 is installed at the bottom of the circulation well. The gas pumped by the air pump 11 is transported through the aeration pipe 14 and enters the circulation well from the aeration head 10 to mix with the water flow entering the circulation well from the lower screen tube 5 to form a gas-water mixture, thereby reducing the density of the water flow. Gradually migrate to the upper section of the circulation well body. The density difference formed inside and outside the well prompts the groundwater at 5 screen tubes in the lower layer of the circulating well to continuously flow into the well. At the same time, the temperature control unit 17 controls the heating unit 7 to heat the rising groundwater to promote the separation of organic pollutants from the groundwater. After the pollutants have been separated, the heated groundwater back-infiltrates into the soil outside the well through the upper screen tube 3. When passing through the soil, it conducts heat to the soil and promotes the removal of organic pollutants (volatile and semi-volatile) outside the well from the soil. The medium is desorbed into the groundwater, and after multiple cycles, the organic pollutants in the soil through which the groundwater flows are removed.

The vacuum extraction device includes a vacuum pump 21 for providing negative pressure, a first extraction pipe 20 for transporting gas, a second valve 18 provided on the first extraction pipe 20 and a second valve 18 provided on the first extraction pipe 20. The second flow meter 19. The vacuum extraction device communicates with the accommodation space 81 inside the circulation well body through the exhaust pipe 2 . In order to adapt to the density of the gas, the exhaust pipe 2 is arranged above the upper screen pipe 3 of the circulation well body. After aeration treatment, the gas containing a large amount of semi-volatile organic pollutants is extracted by the vacuum extraction device through the exhaust pipe 2 and collected outside the well. The vacuum extraction device and the gas purification device 24 are connected through the second extraction pipe 23. The second extraction pipe 23 is provided with a third valve 22 for regulating the gas flow. The extracted gas is purified by the gas purification device 24 and then discharged to The atmosphere may recycle useful components back into the formation.

The circulating well of this application is used to form a circular flow of groundwater, which will not cause significant changes in regional groundwater levels or changes in flow direction. It will have little interference with the surrounding environment and will not easily lead to the spread of organic pollutant contamination, and can effectively remove organic pollutants in groundwater. Improve repair efficiency.

Example 2

This embodiment provides a groundwater circulation well temperature control method, especially an indoor simulation method for removing volatile/semi-volatile organic pollutants in groundwater, which mainly includes a circulation well body, a temperature control device, an aeration device, and a vacuum The functional principles of the extraction device and gas purification system are similar to those in Embodiment 1. The specific implementation includes the following steps:

S1 uses aeration to drive the water level difference formed by groundwater inside and outside the well, so that the water outside the well enters the well through the filter set in the well wall;

S2 uses the first purification equipment located in the well to purify the groundwater entering the well, where the first purification equipment can separate volatile/semi-volatile substances in the groundwater;

S3 uses the second purification equipment located outside the well to collect the semi-volatile substances and process the harmful substances in them.

Among them, S2 includes: heating and/or aeration and/or air extraction operations.

In this embodiment, the water circulation of the circulation well is used to introduce groundwater into the circulation well, and heating in the circulation well causes the organic pollutants to volatilize into the gas phase. Then, a vacuum extraction device is used to extract the volatile gas phase, and the extracted gas phase is directed to the third The above types of organic pollutants are removed by processing in the second purification equipment.

Common organic pollutants in groundwater include benzene series, organochlorine pesticides, polycyclic aromatic hydrocarbons and polychlorinated biphenyls. These volatile/semi-volatile organic pollutants can cause varying degrees of harm to human health. Due to the complex composition of groundwater, multiple pollutants are often mixed. Some complex compositional environments will affect the remediation effect and are difficult to remove. Therefore, before treatment, the concentration and composition of benzene series, organochlorine pesticides, polycyclic aromatic hydrocarbons and polychlorinated biphenyls in groundwater are divided into: volatile pollution (pollutants with a boiling point less than 170°C account for 80% of the total concentration % or more), semi-volatile pollution (pollutants with boiling points between 170°C and 350°C account for more than 80% of the total concentration) and mixed pollution (the concentrations of both volatile and semi-volatile pollutants cannot be ignored). Depending on the grade, different combinations of treatment parameters are used to improve the removal efficiency of pollutants and reduce the risk of leakage of pollutants.

Temperature can affect the saturated vapor pressure of organic pollutants. The higher the groundwater ambient temperature, the greater the saturated vapor pressure of organic matter, and the easier it is for organic matter to volatilize. The increase in heating temperature and the volatilization of semi-volatile organic compounds in groundwater conform to first-order kinetic characteristics. When the water temperature rises from 20°C to 80°C, the volatilization rate of aniline in the water increases by 43 times. Therefore, temperature has an impact on organic pollutants such as aniline in the water. has a greater impact on the evaporation rate. This application uses the heating unit 7 to heat the groundwater extracted into the circulation well. During the heating process, aeration is continued to accelerate the molecular movement in the water flow and promote the rapid diffusion of the temperature generated by the heating unit 7 in the groundwater. Due to practical factors such as the large temperature difference between the groundwater in the edge area and the surrounding environment, and the large heat loss during the flow process, the lower heating temperature generates heat at a slower rate, and due to the low temperature, the molecular movement in the water flow is slow, making The diffusion rate of temperature in the circulation well is slow, so the temperature diffusion area is small. The temperature of the water flow away from the well body or screen section cannot meet the volatilization requirements, and the removal efficiency of pollutants is low. As the heating temperature increases, the rate of heat generation accelerates. The generated heat can supplement the heat lost due to the surrounding temperature difference, and the molecular motion in the water flow is more active, so the temperature diffusion area can be increased, making the temperature farther away from the edge of the well body. It can also meet the volatilization requirements; at the same time, the faster the temperature diffusion speed, the smaller the temperature fluctuation of the water flow in the edge area, which is more conducive to the volatilization of as much semi-volatile organic pollutants in the groundwater into the gas phase as possible.

Increasing the aeration amount in the circulation well will increase the movement speed of water molecules in the circulation well and promote the temperature diffusion in the circulation well. As the aeration amount increases, the temperature diffusion rate and the diffusion area within a certain period of time increase; however, As the amount of aeration increases, the speed of gas flow accelerates, and the rate of heat loss will accelerate, which can easily cause temperature fluctuations in edge water bodies and affect the volatilization of organic matter in edge water bodies; and, as the amount of aeration increases, groundwater and harmful The risk of gas overflowing from the circulation well is also greater, which is not conducive to the normal circulation of groundwater in the circulation well, and can easily cause organic pollutants to overflow to the surface, causing secondary harm.

The following takes the circulating well experimental device as an example to describe the specific setup of this method in detail:

The dimensions of the circulating well experimental device are set to an inner diameter of 45mm and an overall height of 450mm. From bottom to top, there are 50mm high lower screen tube 5, 250mm high middle wall tube 4, 40mm high upper screen tube 3 and 110mm high upper wall tube. A first card holder for fixing the heating unit 7 is provided 45mm from the top of the lower screen tube 5. A second card holder is provided on the side of the first card holder away from the lower screen tube 5 and 160mm away from the first card holder. The distance between the second card holder and the bottom of the upper screen tube 3 is 45mm. The exhaust pipe 2 is set 20mm away from the ground.

Depending on the complexity of the specific situation, the above processing method also includes the following steps:

Taking into account the complex hydrogeological environment of the underground aquifer and the influence of various restoration parameters, different aquifer media (fine sand, medium sand, coarse sand), groundwater flow rate (0.2~0.6m/d), and aeration flow rate (0.1~0.3 m ³ /h), heating temperature (40-80°C) and other conditions, use response surface experiments to determine the values of each parameter in the maximum diffusion range of temperature rise.

Under the equilibrium state of groundwater organic pollutant pollution, remediation and degradation experiments are carried out with various parameters when the temperature diffusion range is the largest. Samples are taken at certain intervals to measure the concentration of organic pollutants in groundwater at different aquifer locations.

Taking the semi-volatile organic pollutant aniline as an example, the repair temperature is set to 80°C, the aeration flow is set to 0.3m ³ /h, and the extraction flow is set to 0.3m ³ /h (due to the small scale of the indoor simulation experiment, the exposure The gas/extraction flow rate is small) and the groundwater flow rate is set to 0.2m/d. Under this condition, the processing speed of the first and second equipment is faster, and aniline can be repaired quickly (as shown in Figure 3).

When the concentration of volatile pollutants such as benzene and TCE in the groundwater is high and the concentration of semi-volatile pollutants such as chlorobenzene, aniline and polycyclic aromatic hydrocarbons is low, the first purification equipment and the second purification equipment adjust themselves The parameters are the first combination. Since the pollutants themselves are easy to volatilize and do not require excessive heating temperatures, the main function of the first purification equipment is aeration to promote volatilization. In order to ensure the removal efficiency of pollutants and ensure that the second purification equipment is sufficient to process the transported pollutants to avoid leakage of pollutants, the first combination is a lower heating temperature and a larger aeration/extraction flow rate, and the aeration after increasing The flow rate and the extraction flow rate are the first flow rate. Preferably, under the first flow rate, increasing the aeration flow rate can ensure that volatile organic pollutants are effectively removed at a lower temperature, and increasing the extraction flow rate can ensure that the pollutants input into the second purification equipment are fully removed. Collect and purify the waste without overflowing and causing harm to the environment. At the same time, due to the increase in aeration flow, the influence radius of the circulation well can be effectively increased and the repair scope can be expanded.

When the concentration of semi-volatile pollutants such as aniline and polycyclic aromatic hydrocarbons in groundwater is high, the parameter combination of the first purification equipment and the second purification equipment is adjusted to the second combination, that is, a higher heating temperature and a lower Aeration/extraction flow rate and higher heating temperature can ensure the removal efficiency of pollutants in the first purification equipment. Lower aeration/extraction flow rate can reduce the risk of high-concentration pollutants evaporating into the air, reducing the subsequent The extraction flow rate and aeration flow rate are the second flow rates. Preferably, in order to ensure the removal efficiency of semi-volatile pollutants, the heating time of the water body in the well body is extended. The extended stay duration is the third duration, and the third duration is longer than the second duration. Preferably, the first duration is 48 hours. The second duration is 60h. The third duration is 72h. The second flow rate is 30~40m ³ /h. The first flow rate is 40 to 50m ³ /h.

This setting method uses different parameter combinations for processing different levels of high-concentration pollutants, which can use slower volatilization and extraction rates for high-risk pollutants to reduce the risk of leakage of high-risk pollutants.

It should be noted that the above specific embodiments are exemplary, and those skilled in the art can come up with various solutions inspired by the disclosure of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the scope of the present invention. within the scope of protection of the invention. Those skilled in the art should understand that the description of the present invention and the accompanying drawings are illustrative and do not constitute limitations on the claims. The scope of protection of the present invention is defined by the claims and their equivalents. The description of the present invention contains multiple inventive concepts, such as "preferably", "according to a preferred embodiment" or "optionally" means that the corresponding paragraph discloses an independent concept, and the applicant reserves the right to propose divisions based on each inventive concept. The right to apply. Throughout the text, the features introduced by "preferably" are only optional and should not be understood as mandatory settings. Therefore, the applicant reserves the right to waive or delete the relevant preferred features at any time.

Claims (7)

1. A groundwater circulation well temperature control system, comprising:

having a lower screen pipe (5) into which groundwater flows and an upper screen pipe (3) from which groundwater flows, and having a circulation well body for collecting and treating groundwater containing organic pollutants, a first purification device for separating organic pollutants from groundwater in the circulation well body, and a second purification device for treating separated gas-phase organic pollutants to remove hazards,

the first purifying device is arranged in the liquid environment in the well body of the circulating well, and the second purifying device is arranged outside the well of the circulating well and communicated with the circulating well to collect gas containing organic pollutants;

the first purifying device comprises a temperature control device for heating the underground water in the well body of the circulating well to promote the volatilization of organic pollutants in the underground water and an aeration device for injecting air into the underground water in the well body of the circulating well to drive the underground water to circularly flow;

the system is configured to process with different combinations of process parameters depending on contaminant levels;

under the condition that the concentration of volatile pollutants in underground water is high and the concentration of semi-volatile pollutants is low, the first purifying equipment and the second purifying equipment adjust self parameters to be a first combination, the first combination is low heating temperature and large aeration/extraction flow, the aeration flow and the extraction flow after rising are first flow, wherein when the organic pollutants in the underground water are mainly volatile organic matters, the first purifying equipment and the second purifying equipment are set as: setting the repair temperature at 40-60 ℃ and the aeration flow rate at 50m ³ The extraction flow rate is set to be 50m ³ /h；

When the concentration of the semi-volatile pollutants in the underground water is high, the first purifying device and the second purifying device adjust the parameters of the first purifying device and the second purifying device to be a second combination, wherein the second combination is high heating temperature and low aeration/extraction flow, the reduced extraction flow and aeration flow are the second flow, and when the organic pollutants in the underground water are mainly semi-volatile organic matters, the parameters of the first purifying device and the second purifying device are set as follows: setting the repair temperature at 60-80 ℃ and the aeration flow at 30m ³ /h, pumpThe lifting rate is set to be 30m ³ /h；

When the organic pollutant in the underground water is a semi-volatile and volatile organic mixture, the parameter setting of the first purifying equipment and the second purifying equipment adopts a step-by-step heating mode, and the restoration temperature is firstly set to be 40-60 ℃ and the aeration flow is set to be 40m ³ The extraction flow rate per hour is set to 40m ³ And/h, when the removal rate of the volatile pollutants exceeds 80%, the repair temperature is increased to 60-80 ℃, the removal of the semi-volatile pollutants is accelerated, different treatment parameter combinations are adopted based on the organic pollutants with different volatility in the underground water, and the temperature rise and the aeration/extraction flow can be adjusted according to actual conditions.

2. The groundwater circulation well temperature control system according to claim 1, wherein,

the temperature control device comprises a temperature control unit (17), a temperature rising unit (7) and a temperature monitoring unit (9), wherein the temperature rising unit (7) is arranged between an upper layer screen pipe (3) and a lower layer screen pipe (5) in a well body containing space of the circulating well so as to heat underground water in the well body of the circulating well.

3. Groundwater circulation well temperature control system according to claim 1, characterized in that the second purification device comprises a vacuum extraction device (21) for extracting gaseous organic pollutants from the circulation well body and a gas purification device (24) for treating organic pollutants, the vacuum extraction device extracting exhaust gases through an exhaust pipe (2) arranged above the upper screen pipe (3).

4. Groundwater circulation well temperature control system according to claim 2, characterized in that the temperature monitoring unit (9) is arranged close to the upper screen pipe (3) for monitoring the temperature of well water to be output from the circulation well after heating.

5. Groundwater circulation well temperature control system according to claim 2, characterized in that the heating temperature of the temperature raising unit (7) is 40-80 ℃.

6. Groundwater circulation well temperature control system according to claim 1, characterized in that an upper sealing cover (1) and a lower sealing cover (6) for preventing the entry of gases with organic pollutants into the atmosphere and groundwater are provided at the end of the circulation well body close to the earth's surface and at the end facing away from the earth's surface, respectively.

7. A temperature controlled circulation well system for removing organic contaminants from groundwater, characterized by using the groundwater circulation well temperature control system according to claim 1, comprising the steps of:

using aeration driving function to make underground water in the stratum enter the well through the filtering part arranged in the well wall;

purifying the underground water entering the well by using first purifying equipment positioned in the well, and separating volatile/semi-volatile substances in the underground water;

collecting the volatile/semi-volatile substances by using a second purifying device positioned outside the well, and treating harmful substances therein;

wherein the step of purifying groundwater entering the well using a first purifying device located in the well, and separating volatile/semi-volatile materials from the groundwater comprises: heating and/or aeration and/or evacuation operations.