Method and system for solar thermal activation of oxidative remediation of contaminated soil

Abstract

The present application relates to a solar heat-activated oxidation method and system for repairing contaminated soil; the method comprises the following steps: detecting the pollution condition of the contaminated soil, determining the preparation parameters of the repair reagent and the set temperature of the heat medium; introducing the heated heat medium into the contaminated soil, and monitoring the temperature of the contaminated soil in real time, and feeding back and adjusting the amount of heat medium introduced to maintain the temperature of the contaminated soil at the set temperature; introducing the prepared repair reagent into the contaminated soil, and performing multi-phase extraction on the contaminated soil, monitoring the pollution condition of the contaminated soil in real time, and feeding back and adjusting the preparation parameters of the repair reagent and / or the set temperature of the heat medium. The present application uses clean energy for heating, improves the heating method, reduces energy consumption, and in the repair process, the temperature and pollution condition of the contaminated soil are detected in real time and adjusted according to the detection results, which can ensure uniform heating of the contaminated soil and efficient implementation of the contaminated soil repair operation, save the amount of repair reagent used, and shorten the treatment cycle.

Description

Technical Field

[0001] This invention relates to the field of soil remediation technology, and in particular to a solar thermal activated oxidation remediation method and system for contaminated soil. Background Technology

[0002] With the rapid development of society and the economy, environmental issues have gradually gained attention, among which soil pollution is becoming increasingly serious. Chemical oxidation remediation mainly involves adding chemical oxidants to the soil and using heating to enhance the decomposition or volatilization of pollutants, causing them to undergo an oxidation reaction, ultimately degrading or transforming the pollutants into low-toxicity, low-transfer products.

[0003] Existing chemical oxidation remediation methods for contaminated soil suffer from the following problems: high energy consumption, uneven temperature distribution, difficulty in controlling the thermal activation temperature of remediation agents, and some remediation agents operating outside their optimal activation temperature range, leading to reduced remediation effectiveness and reduced efficiency. Therefore, a solar thermal activation oxidation remediation system and method for contaminated soil is urgently needed to address these issues. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for solar thermal activation oxidation remediation of contaminated soil, comprising the following steps:

[0005] The contamination status of the soil is detected, and the preparation parameters of the remediation agent and the set temperature of the heat medium used to heat the contaminated soil are determined based on the contamination status.

[0006] The heat medium heated by the solar heating unit is introduced into the contaminated soil, and the temperature of the contaminated soil is monitored in real time. The amount of heat medium introduced is adjusted accordingly to maintain the internal temperature of the contaminated soil at the set temperature.

[0007] The prepared remediation agent is introduced into the contaminated soil, and multiphase extraction is performed on the contaminated soil. During the remediation process, the contamination status of the contaminated soil is monitored in real time, and the remediation agent preparation parameters and / or the set temperature of the heat medium are adjusted accordingly.

[0008] Furthermore, real-time monitoring of soil contamination includes:

[0009] Based on real-time monitoring results of pollution, the concentration of remediation agents introduced into the polluted soil is adjusted. When the pollutant degradation rate is detected to be less than the set range for a certain period of time, the set temperature of the heat medium introduced into the polluted soil is increased.

[0010] Furthermore, the set temperature of the heat medium includes the initial set temperature of the heat medium, and the determination of the initial set temperature of the heat medium specifically includes:

[0011] The types and concentrations of pollutants in contaminated soil are detected, and based on the test results, the types and concentrations of remediation agents used to remediate the contaminated soil, as well as the initial set temperature of the heat medium used to activate the remediation agents, are determined.

[0012] Furthermore, the set temperature of the heat medium also includes the optimal set temperature of the heat medium, and the determination of the optimal set temperature of the heat medium specifically includes:

[0013] The set temperature of the heat medium is adjusted every once in a while, and the pollution status data of the contaminated soil at the corresponding set temperature is collected. The degradation rate of pollutants, energy consumption, and the ratio of degradation rate to energy consumption are obtained through multiple sets of pollution status data. The set temperature of the heat medium with the largest ratio is selected as the optimal set temperature, and the temperature of the heat medium introduced into the contaminated soil is adjusted to the optimal set temperature.

[0014] Furthermore, if the temperature of the contaminated soil is less than the set temperature of the heat medium, the solar heating unit supplies heat medium to the contaminated soil until the temperature of the contaminated soil is not lower than the set temperature of the heat medium; if the temperature of the contaminated soil is greater than or equal to the set temperature of the heat medium, the solar heating unit stops supplying heat medium to the contaminated soil, and the heat medium is stored and kept warm in the solar heating unit.

[0015] Furthermore, the solar heating unit includes a solar heating component and a storage component for storing a heat medium, the storage component being connected to the solar heating component; if the heating temperature of the solar heating component is greater than or equal to the set temperature of the heat medium, the heat medium heated to the set temperature is sent to the storage component for storage and later use; if the heating temperature of the solar heating component is less than the set temperature of the heat medium, the heat medium in the storage component is heated to the set temperature.

[0016] Furthermore, if the pollutant concentration in the contaminated soil is detected to be greater than the pollutant concentration control value, the prepared remediation agent is delivered to the contaminated soil to react with the pollutants in the soil through oxidation; if the pollutant concentration in the contaminated soil is detected to be less than or equal to the pollutant concentration control value, the delivery of the remediation agent and the delivery of the heat medium to the contaminated soil are stopped.

[0017] Furthermore, if the multiphase extraction pressure of the contaminated soil is less than the pressure set value, the multiphase extraction pressure is adjusted until the multiphase extraction pressure is greater than or equal to the pressure set value, and multiphase extraction is continued for a period of time.

[0018] Furthermore, the waste gas and wastewater collected by multiphase extraction of the contaminated soil are purified and then discharged.

[0019] On the other hand, the present invention also provides a solar thermal activated oxidation remediation system for contaminated soil, comprising:

[0020] A solar heating unit is used for heating medium and storing heat medium. The solar heating unit is connected to a heat medium heating pipe inserted into the contaminated soil.

[0021] A dosing unit is used for the preparation and storage of remediation agents, and the dosing unit is connected to a dosing pipe inserted into the contaminated soil.

[0022] A multiphase extraction unit, wherein the multiphase extraction unit is connected to a multiphase extraction pipe inserted into the contaminated soil;

[0023] The data acquisition unit includes a temperature detection device and a pollutant detection device. The temperature detection device is interlocked with the solar heating unit to monitor the temperature of the contaminated soil and provide feedback to control the flow rate of the heating medium in the heating pipe. The pollutant detection device is interlocked with the solar heating unit and the dosing unit respectively to monitor the contamination status of the contaminated soil and provide feedback to control the set temperature of the heating medium in the solar heating unit and the preparation parameters of the remediation agent in the dosing unit.

[0024] By employing the above technical solutions, this invention has the following advantages compared to existing technologies:

[0025] 1) The solar thermal activation oxidation remediation method for contaminated soil provided by the present invention uses clean energy solar energy for heating, improves the heating method, reduces energy consumption, and monitors the temperature and contamination status of the contaminated soil in real time during the remediation process and adjusts the system according to the monitoring results, which can ensure uniform heating of the contaminated soil and efficient implementation of the contaminated soil remediation operation, save the amount of remediation agents used, and shorten the treatment cycle.

[0026] 2) The method for solar thermal activation oxidation remediation of polluted soil provided by the present invention adopts a combined solar and electric heating system, which can realize green energy powered by solar energy and ensure the stability of heating, thus making up for the drawbacks of unstable heating caused by weather and heat collection area. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of the solar thermal activated oxidation remediation system for contaminated soil in this invention;

[0029] Figure 2 This is a schematic diagram of pollutant degradation in this invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the accompanying drawings, the dimensions and relative dimensions of certain parts may be enlarged for clarity.

[0031] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connection" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] In the description of this invention, terms such as "upper," "lower," "left," "right," "front," and "rear," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] Furthermore, in the description of this invention, the terms "first" and "second" are used merely for descriptive distinction and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Additionally, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0034] Example 1

[0035] This invention provides a method for solar thermal activation oxidation remediation of contaminated soil, comprising the following steps:

[0036] The contamination status of the soil is detected, and the preparation parameters of the remediation agent and the set temperature of the heat medium used to heat the contaminated soil are determined based on the contamination status.

[0037] The heat medium heated by the solar heating unit 1 is introduced into the contaminated soil, and the temperature of the contaminated soil is monitored in real time. The amount of heat medium introduced is adjusted accordingly to maintain the internal temperature of the contaminated soil at the set temperature.

[0038] The prepared remediation agent is introduced into the contaminated soil, and multiphase extraction is performed on the contaminated soil. During the remediation process, the contamination status of the contaminated soil is monitored in real time, and the remediation agent preparation parameters and / or the set temperature of the heat medium are adjusted accordingly.

[0039] Specifically, this invention can perform in-situ remediation of contaminated soil. During use, a solar heating unit 1 provides a heat source, and the heat medium can be, but is not limited to, hot water or steam. In this embodiment, hot water is preferred. The heat medium is introduced into the contaminated soil, heating it through thermal radiation. The prepared remediation agent is then delivered into the contaminated soil, ensuring full contact between the agent and the soil. During the application process, multiphase extraction is performed on the contaminated soil, creating negative pressure within it. This allows the remediation agent to quickly penetrate the soil and react chemically with the pollutants, thereby remediating the soil. The gaseous or liquid pollutants generated by the oxidation reaction are extracted and collected outside the contaminated soil through multiphase extraction, preventing secondary pollution caused by the diffusion of pollutants. This also reduces the concentration of byproducts in the contaminated soil, promotes the oxidation reaction towards the byproducts, and increases the reaction rate. Throughout the remediation process, the temperature change of the contaminated soil can be monitored in real time, allowing for feedback adjustment of the amount of heat medium introduced into the contaminated soil by the solar heating unit 1, ensuring the soil temperature remains within a set range.

[0040] Preferably, before injecting the remediation agent, a heating medium can be introduced to preheat the contaminated soil. The preheating temperature is lower than the set temperature of the heating medium. After the contaminated soil temperature reaches the preheating temperature, the remediation agent is then introduced. This can improve the reaction efficiency between the remediation agent and the pollutants and shorten the remediation time. Alternatively, a heating medium can be introduced into the contaminated soil simultaneously with the remediation agent. During the introduction of the remediation agent, multiphase extraction is performed on the contaminated soil. Multiphase extraction accelerates the diffusion of the agent in the soil, ensuring uniform distribution and thorough remediation. Simultaneously, the pressure generated during the injection of the agent using in-situ chemical oxidation maintains a constant pressure balance in the soil, allowing for the simultaneous removal of different forms of organic pollutants. This addresses the limitations of single technologies such as in-situ chemical oxidation (ISCO) which only targets oxidizable substances (adsorbed state) and multiphase extraction (MPE) which only targets volatile and free substances.

[0041] The optimized implementation method involves detecting the pollution status of contaminated soil, specifically including the types, concentrations, and volume of pollutants to fully understand the pollution distribution. The preparation of remediation agents includes setting the appropriate agent based on the type of pollutant, using a suitable agent to oxidize the pollutants, and determining the agent concentration based on the pollutant concentration. The prepared remediation agent is then introduced into the contaminated soil for oxidation remediation. As the oxidation reaction proceeds, the pollutant concentration in the soil gradually decreases. Real-time monitoring of the pollutant concentration is conducted, and the concentration of the remediation agent introduced into the soil is adjusted based on the monitoring results. This ensures the oxidation reaction proceeds while conserving remediation agent usage, saving costs, and avoiding environmental pollution. If the pollutant degradation rate is found to be below the set range for a certain period, it indicates poor remediation effectiveness. In this case, the set temperature of the heat medium introduced into the contaminated soil can be increased to ensure the smooth reaction between the remediation agent and the pollutants. For example, the set temperature of the heat medium can be increased by 10°C sequentially to ensure the pollutant degradation rate remains within the set range. When the temperature of the heat medium increases, the vapor pressure of the reagent increases. In order to ensure that the reagent remains liquid and circulates in the system, it is necessary to increase the pressure setting value of the multiphase extraction pipeline in the multiphase extraction unit.

[0042] If the concentration of pollutants in the soil exceeds the controlled value, it indicates that the pollutants are exceeding the standard and remediation of the contaminated soil is required. If the concentration of pollutants in the soil is less than or equal to the controlled value, it indicates that the pollutants are not exceeding the standard and no remediation is required. In this invention, the concentration of pollutants in the contaminated soil is monitored in real time. When the concentration exceeds the controlled value, a remediation agent is introduced to remediate the soil until the concentration of pollutants in the soil is detected to be equal to or less than the controlled value, at which point the introduction of the remediation agent is stopped. The remediation process is repeated once the concentration of pollutants in the soil exceeds the standard.

[0043] In an optimized implementation, the set temperature of the heat medium includes an initial set temperature. Determining the initial set temperature specifically involves: detecting the types and concentrations of pollutants in the contaminated soil, and based on the detection results, determining the type and concentration of the remediation agent used to remediate the contaminated soil, as well as the initial set temperature of the heat medium used to activate the remediation agent. The initial set temperature of the heat medium can be determined based on the detected types of pollutants, and this initial set temperature is the thermal activation temperature of the remediation agent. During the initial remediation of contaminated soil, the heat medium is heated to the initial set temperature and then introduced into the contaminated soil to heat the soil and activate the remediation agent.

[0044] Soil and groundwater contamination can be categorized into several types: sites primarily contaminated with polycyclic aromatic hydrocarbons (PAHs), sites primarily contaminated with pesticides, and sites primarily contaminated with petroleum hydrocarbons. Different contaminants have different concentration control values, concentration screening values, types of remediation agents, and thermal activation temperatures. Persulfate can be used for the remediation of sites primarily contaminated with PAHs, potassium permanganate for sites primarily contaminated with pesticides, and Fenton's reagent (H₂O₂ + Fe²⁺) for other purposes. 2+ This is used for the remediation of contaminated sites primarily composed of petroleum hydrocarbons. The table below shows the remediation parameters for some pollutants. When the pollutant concentration is detected to exceed the concentration control value, remediation is required until the pollutant concentration is reduced below the concentration screening value.

[0045] Table 1. Remediation parameters for pollutants (unit: mg / kg)

[0046]

[0047] The initial set temperature of the aforementioned heat medium is not the optimal thermal activation oxidation temperature. The optimal set temperature of the heat medium needs to be determined by the pollutant concentration degradation rate and energy consumption during the remediation process. Specifically, the set temperature of the heat medium is adjusted every once in a while, and the pollution status data of the contaminated soil at the corresponding set temperature is collected. The degradation rate of pollutants, energy consumption, and the ratio of degradation rate to energy consumption are obtained through multiple sets of pollution status data. The set temperature of the heat medium with the largest ratio is selected as the optimal set temperature. The degradation effect of pollutants is good and the energy consumption is relatively low at this temperature, so it can be used as the optimal set temperature of the heat medium. This optimal set temperature is fed back to the solar heating unit.

[0048] During the remediation process, the temperature of the contaminated soil is monitored. If the soil temperature is lower than the set soil temperature, the solar heating unit operates, providing a heat transfer medium to the contaminated soil to ensure that the soil temperature reaches the set temperature. If the soil temperature is higher than or equal to the set soil temperature, it indicates that the soil temperature has reached the activation temperature of the remediation agent, and the soil has heat-insulating properties. In this case, heating of the contaminated soil can be suspended, and the solar heating unit stops providing the heat transfer medium. The heat transfer medium can be stored for later use to save energy. The set soil temperature is equal to the set temperature of the heat transfer medium.

[0049] In an optimized implementation, the solar heating unit 1 includes a solar heating component and a storage component for storing the heat medium. The storage component is connected to the solar heating component and can be used to store the heat medium and perform secondary heating on it. If the heating temperature of the solar heating component is greater than or equal to the set temperature of the heat medium, the heat medium heated to the set temperature is sent to the storage component for storage and later use. If the heating temperature of the solar heating component is less than the set temperature of the heat medium, the heat medium in the storage component is heated to the set temperature. The solar heating component can use sunlight to heat water. Under sufficient sunlight, it can fully heat the medium. The heated hot water is then introduced into the contaminated soil to activate the remediation agent. To save energy and reduce energy loss, excess hot water can be stored in the storage component, which is equipped with an insulation layer to reduce energy loss. Simultaneously, the storage component is also equipped with a heating device for secondary heating of the heat medium. When the solar heating component cannot heat the medium to the set temperature, the heat medium can be heated to the set temperature in the storage component and then introduced into the contaminated soil to heat it.

[0050] Specifically, see the instruction manual. Figure 1As shown, the solar heating component includes a heat collection plate 11 and a hot water collection tank 12. The heat collection plate 11 and the hot water collection tank 12 form a circulation loop through a pipeline. The hot water collection tank 12 is also connected to a water inlet pipe 13, which can replenish water to the hot water collection tank 12 so that the water level in the hot water collection tank 12 is within a set water level range. The storage component includes a hot water supply tank 14, which is equipped with an electric heater for secondary heating. The hot water supply tank 14 is connected to the hot water collection tank 12 through a first water supply pipeline 15. The heat collection plate 11 can preheat the water in the hot water collection tank 12. After the water in the hot water collection tank 12 is heated, it is sent to the hot water supply tank 14 through the first water supply pipeline 15 for storage and use. To facilitate water temperature detection, a first temperature detector is installed on the hot water collection tank 12, and a second temperature detector is installed on the hot water supply tank 14, for real-time monitoring of the water temperature inside the tanks. Water level sensors for water level detection are also installed on both the hot water collection tank 12 and the hot water supply tank 14. A heat transfer medium heating pipe 2 is buried within the contaminated soil. The heat transfer medium heating pipe 2 is inserted into the contaminated soil. The inlet end of the heat transfer medium heating pipe 2 is connected to the hot water supply tank 14 via a second water supply pipe 16, and the outlet end is connected to the hot water collection tank 11 via a third water supply pipe 17. When the contaminated soil needs heating, hot water from the hot water supply tank 14 is sent to the heat transfer medium heating pipe 2 via the second water supply pipe 16 to heat the soil. A third temperature detector is installed on the heat transfer medium heating pipe 2. When the third temperature detector detects that the water temperature inside the pipe is lower than the set value, the water in the heat transfer medium heating pipe 2 flows back to the hot water collection tank 12 via the third water supply pipe 17 for reheating. A fourth water supply pipeline 18 is provided between the hot water collection tank 12 and the second water supply pipeline 16, and the hot water in the hot water collection tank 12 can also be directly sent to the heat medium heating pipeline 2 for use. There are several heat medium heating pipelines 2, and each heat medium heating pipeline 2 is evenly spaced in the contaminated soil, which can uniformly heat the contaminated soil.

[0051] Preferably, the inlet pipe 13 is equipped with a first water pump 19, a first valve 110, and a second valve 111; the pipes of the heat collection plate 11 and the heat collection tank 12 are equipped with a second water pump 112, a third valve 113, and a fourth valve 114; the first water delivery pipe 15 is equipped with a third water pump 115, a fifth valve 116, and a sixth valve 117; the second water delivery pipe 16 is equipped with a fourth water pump 118, a seventh valve 119, and an eighth valve 120; the third water delivery pipe 17 is equipped with a fifth water pump 121, a ninth valve 122, and a tenth valve 123; and the fourth water delivery pipe is equipped with an eleventh valve 124.

[0052] Preferably, in order to monitor the temperature of the contaminated soil in real time, a temperature detection device 3 is also provided. The temperature detection device 3 includes several temperature sensors. Multiple temperature monitoring points are set in the contaminated soil, and each temperature monitoring point is equipped with a temperature sensor. Multi-point temperature collection is carried out in the contaminated soil, and the detection is more accurate.

[0053] Each of the aforementioned water pumps, temperature detectors, water level sensors, and temperature detection devices is connected to controller 4. Controller 4 can collect and analyze the detection data, and then feed it back to the corresponding water pump to open and close the pipeline.

[0054] The minimum and maximum water levels of the hot water collection tank 12 are set, and the water level sensor can detect the actual water level in the hot water collection tank in real time. If the actual water level is greater than or equal to the maximum set water level, the controller controls the first water pump 19, the first valve 110, and the second valve 111 to close, and controls the second water pump 112, the third valve 113, and the fourth valve 114 to open, so as to circulate and heat the central heat collection plate; the temperature of the hot water collection tank 12 is set, and the first temperature detector in the hot water collection tank 12 collects the actual temperature value of the tank and compares the actual temperature value with the set temperature value; if the actual temperature value is greater than or equal to the set temperature, the fourth water pump 118, the seventh valve 119, the eighth valve 120, and the eleventh valve 124 are opened to supply hot water to the heat medium heating pipe 2; if the actual temperature value is less than or equal to the set temperature, the controller controls the first water pump 19, the first valve 110, and the second valve 111 to close, and controls the second water pump 112, the third valve 113, and the fourth valve 114 to open, so as to circulate and heat the central heat collection plate; if the actual temperature value is less than or equal to the set temperature, the controller controls the second water pump 112, the third valve 113, and the fourth valve 114 are opened ... fourth water pump 118, the seventh valve 119, the eighth valve 120, and the el If the temperature value is less than the set temperature, the eleventh valve 124 is closed, and the water in the hot water collection tank 12 is transferred to the hot water supply tank 14. The secondary heating mode is activated, and the water in the hot water supply tank 14 is heated to the set temperature of the heat medium. Then, it is sent to the heat medium heating pipe 2 through the second water supply pipe 16. When the hot water in the hot water collection tank 12 is used up to the point where the water level is lower than the minimum set water level, the controller controls the first water pump 19, the first valve 110 and the second valve 111 to open, and continue to supply water to the hot water collection tank 12. The controller activates the secondary heating mode and opens the third water pump 115, the fifth valve 116 and the sixth valve 117. The controller sets the minimum and maximum water levels for the hot water tank 14, collects the actual water level value of the hot water tank 14, and compares the actual water level with the set water level. If the actual water level value is greater than or equal to the maximum set water level, the controller controls the third water pump 115, the fifth valve 116, and the sixth valve 117 to close. The controller also sets the temperature set value for the hot water tank 14, collects the temperature from the second temperature detector inside the hot water tank 14, and compares it with the temperature set value. If the actual temperature value is greater than or equal to the set temperature value, the controller turns off the electric heating and turns on the fourth water pump 118, the seventh valve 119, and the eighth valve 120 to supply hot water to the heat medium heating pipe 2. Once the hot water in the hot water tank 14 is used up to a level lower than the minimum set water level, the controller continues to turn on the third water pump 115, the fifth valve 116, and the sixth valve 117 to supply water to the hot water tank 14. The third temperature detector inside the heat medium heating pipe 2 monitors the water temperature inside the pipe. When the actual temperature inside the pipe is less than the set temperature inside the pipe, the controller opens the fifth water pump 121, the ninth valve 122 and the tenth valve 123 to return the water in the pipe to the hot water collection tank 12 for solar heating again.

[0055] In this embodiment, the set temperature of the hot water collection tank is equal to the set temperature of the heat medium, and the set temperature of the hot water supply tank is equal to the set temperature of the heat medium. When the temperature of the contaminated soil is lower than the set soil temperature, the solar heating unit introduces the heat medium into the heat medium heating pipe. If the solar heating unit is already supplying heat, but the temperature of the contaminated soil is still lower than the set soil temperature, the amount of heat medium introduced can be increased or the heating time can be extended.

[0056] In some embodiments, if there is a surplus of hot water in the hot water collection tank after supplying the heat medium to the heating pipe, the heat medium can be sent to the hot water supply tank for storage. The hot water supply tank is equipped with an insulation layer to keep the hot water warm and reduce the energy loss of the hot water. The hot water stored in the hot water supply tank can be used to heat the polluted soil at night or on rainy days, which can effectively reduce energy consumption.

[0057] In an optimized implementation method, if the pollutant concentration in the contaminated soil is detected to be greater than the pollutant concentration control value, the prepared remediation agent is delivered to the contaminated soil to react with the pollutants in the soil through oxidation; if the pollutant concentration in the contaminated soil is detected to be less than or equal to the pollutant concentration control value, the delivery of the remediation agent and the delivery of the heat medium to the contaminated soil are both stopped.

[0058] Specifically, see the instruction manual. Figure 1 As shown, the repair agent is prepared through the dosing unit 5, which includes a dissolving tank 51 and a storage tank 52. The storage tank 52 is connected to the dissolving tank 51 through a first delivery pipeline 53. The repair agent is dissolved and prepared in the dissolving tank 51 and then sent to the storage tank 52 for storage. The first delivery pipeline 53 is equipped with a sixth water pump 54, a twelfth valve 55, and a thirteenth valve 56. The dissolving tank 51 is equipped with a stirrer. The dissolving tank 51 is connected to a dosing pipe 57 and a water dosing pipe 58. The dosing pipe 57 is equipped with a flow meter 59 and a dosing solenoid valve 510. The water dosing pipe 58 is equipped with a water dosing solenoid valve 511. Water level sensors are connected to the dissolving tank 51 and the storage tank 52 respectively to monitor the water level in the tanks. A dosing pipeline 6 is buried within the contaminated soil. The dosing pipeline 6 is connected to a storage tank 52 via a second delivery pipeline 512. The second delivery pipeline 512 is equipped with a discharge pump 513, a fourteenth valve 514, and a fifteenth valve 515. Multiple dosing pipelines 6 are installed, evenly spaced within the contaminated soil. Each dosing pipeline 6 has several dosing holes through which remediation agents can enter the soil for remediation.

[0059] When the concentration of pollutants exceeds the standard, the preparation unit 5 begins to prepare and supply the remediation agent. The remediation agent is prepared according to the type of pollutant, and then mixed evenly in the dissolving tank 51. It is then sent to the storage tank and delivered to the dosing pipeline through the second delivery pipeline.

[0060] The dosing unit 5 is activated, and the oxidizing agent is prepared according to the main pollutant site. The set water level of the agent in the dissolving tank is set, and the water level sensor in the dissolving tank collects the actual water level data and compares the actual water level with the set water level. If the actual water level in the dissolving tank is greater than or equal to the set water level, the controller controls the dosing solenoid valve and the water dosing solenoid valve to close. The controller starts the agitator, sets the agitator's running time, and compares the actual running time with the set running time. If the actual running time is equal to the set running time, the agitator is turned off, and the sixth water pump 54, the twelfth valve 55, and the thirteenth valve 56 are turned on to send the prepared remediation agent to the storage tank. The set water level of the agent in the storage tank is set, and the water level sensor in the storage tank collects the actual water level data and compares the data with the set water level. If the actual water level is greater than or equal to the set water level, the controller controls the sixth water pump 54, the twelfth valve 55, and the thirteenth valve 56 to close. The prepared remediation agent is stored in a storage tank, awaiting agent delivery instructions. If the soil contaminant concentration exceeds the control limit, remediation is required. The discharge pump 513, the fourteenth valve 514, and the fifteenth valve 515 are opened to deliver the agent into the dosing pipeline. If the soil contaminant concentration is below the screening value, no agent supply is needed, and the discharge pump 513, the fourteenth valve 514, and the fifteenth valve 515 are closed. When the agent in the storage tank is depleted, the dosing unit resumes dosing. The sixth water pump, discharge pump, water level sensor, and agitator are all connected to the controller, enabling intelligent control.

[0061] Contaminated soil undergoes multiphase extraction via a multiphase extraction unit 7. A multiphase extraction pipeline 8 is buried within the contaminated soil and connected to the multiphase extraction unit 7. The multiphase extraction unit 7 includes an extraction well connected to the multiphase extraction pipeline 8. The extraction well is equipped with a gas-liquid separator 71 and an oil-water separator 72 for treating waste gas and wastewater. The gas-liquid separator 71 is connected to a tail gas treatment device 73, and the oil-water separator 72 is connected to a hazardous waste treatment device 74 and a sewage treatment device 75. Multiple multiphase extraction pipelines 8 are evenly spaced within the contaminated soil, and each pipeline 8 has several extraction holes for multiphase extraction. At least a portion of the multiphase extraction pipelines 8 are connected to the gas-liquid separator 71, and at least a portion are connected to the oil-water separator 72. Each of the multiphase extraction pipes 8 is equipped with a vacuum pump 76 at its front end. When the vacuum pump is turned on, a negative pressure is formed inside the pipe, which can accelerate the flow of the remediation agent in the contaminated soil. It can also recover and treat the waste gas and wastewater generated by the oxidation reaction, and discharge them after they meet the standards.

[0062] Preferably, each of the multiphase extraction pipelines 8 is equipped with a pressure sensor for monitoring the gas pressure inside the pipeline. A sixteenth valve 77 and a seventeenth valve 78 are provided on the pipeline between the gas-liquid separator 71 and the multiphase extraction pipeline; a seventh water pump 79, an eighteenth valve 710, and a nineteenth valve 711 are provided on the pipeline between the oil-water separator 72 and the multiphase extraction pipeline; an eighth water pump 712, a twentieth valve 713, and a twenty-first valve 714 are provided on the pipeline between the gas-liquid separator 71 and the oil-water separator 72; and an air pump 715, a twenty-second valve 716, and a twenty-third valve 717 are provided on the pipeline between the gas-liquid separator 71 and the exhaust gas treatment device 73. Each of the vacuum pumps, water pumps, air pumps, gas-liquid separators, and oil-water separators is connected to the controller. While injecting remediation agents into the contaminated soil, the vacuum pumps are turned on for extraction. If the multiphase extraction pressure of the contaminated soil is less than the pressure set value, the vacuum pumps are turned on and the multiphase extraction pressure is adjusted until the multiphase extraction pressure is greater than or equal to the pressure set value. Then, the controller controls the vacuum pump 76, water pump 7, sixteenth valve 77, seventeenth valve 78, eighteenth valve 710, and nineteenth valve 711 to close; and turns on the gas-liquid separator, eighth water pump 712, air pump 715, oil-water separator, twentieth valve 713, twenty-first valve 714, twenty-second valve 716, and twenty-third valve 717 to perform end-of-pipe wastewater treatment, exhaust gas treatment, and hazardous waste collection.

[0063] The pressure of the multiphase extraction pipeline is related to the vapor pressure of the remediation agent, temperature, and the contact time between the remediation agent and the soil. The extraction pressure is typically higher than the vapor pressure of the remediation agent (a pressure gauge is installed in the dosing unit to measure the vapor pressure) to ensure the remediation agent remains liquid and circulates within the system. Increased temperature leads to an increase in the vapor pressure of the remediation agent, thus requiring higher extraction pressure. Longer contact times necessitate higher pressure to maintain the fluidity of the remediation agent and extraction efficiency. Higher extraction pressure increases the fluidity of the remediation agent and the rate of contaminant transport, thereby increasing the reaction rate. A maximum set threshold for the extraction pressure is established. The pressure in the multiphase extraction pipeline is kept below this threshold to prevent soil structure damage and collapse due to high pressure, which would negatively impact the remediation effect and reduce energy consumption.

[0064] The optimized implementation also includes a pollutant detection device, preferably a photoionization detector (PID sensor) and a water quality analyzer. The photoionization detector is installed at the extraction well outlet and the exhaust / vent of the tail gas treatment device, while the water quality analyzer is installed at the extraction well outlet and the wastewater treatment device inlet / outlet. The photoionization detector and water quality analyzer can detect the types and concentrations of pollutants in groundwater and soil in real time. Based on the detection results, a remediation agent is prepared and introduced into the contaminated soil for oxidative remediation.

[0065] In this embodiment, before remediating contaminated soil, the contamination status of the contaminated soil is detected and analyzed. Specifically, the types and concentrations of pollutants in the contaminated soil and the volume of contaminated soil are detected and analyzed. Based on the analysis results, the burial depth, burial length, and burial density of the heat medium heating pipe, chemical dosing pipe, and multiphase extraction pipe laid in the contaminated soil are determined, as well as the types, concentrations, and activation temperatures of the remediation agents used to remediate the contaminated soil are determined.

[0066] This invention utilizes clean solar energy for heating, improving heating methods and control mechanisms to solve the problems of high energy consumption and uneven heating in removing organic pollutants from soil. It employs a combined solar and electric heating system, achieving both green energy supply from solar power and ensuring stable heating, overcoming the drawbacks of solar power's instability due to weather and collector area limitations. The integration of the solar heating unit, chemical dispensing unit, multiphase extraction unit, and controller enables real-time online monitoring and intelligent control, improving soil remediation efficiency. PID control and constant temperature and pressure control further enhance the utilization of thermal energy.

[0067] The following specific examples illustrate this.

[0068] Multiphase extraction unit 7 is activated, and the multiphase extraction pipeline pressure F < F 设定 Vacuum pump 76, seventh water pump 79, sixteenth valve 77, seventeenth valve 78, eighteenth valve 710, and nineteenth valve 711 are activated. A photoionization detector and a rapid water quality analyzer detect the concentrations of gaseous and water-soluble pollutants, analyze the pollutant composition, select the type of remediation agent, and set the thermal activation temperature of the remediation agent. In this embodiment, the soil pollutant is mainly polycyclic aromatic hydrocarbons (PAHs), with a naphthalene concentration >700 mg / kg. Therefore, persulfate (PMS) is required for remediation, and the thermal activation temperature of the remediation agent is set to 40°C. The set temperature of the heat medium is also 40°C.

[0069] The preparation unit 5 begins to prepare the repair agent. The actual water level in the dissolving tank 51 is recorded as Q3, the actual water level in the storage tank 52 is recorded as Q4, and the stirring time of the stirrer is t. The water level sensors of the dissolving tank 51 and the storage tank 52, as well as the stirrer, are electrically connected to the controller 4.

[0070] When Q3<Q 设定3 , t < t 设定 At this time, turn on the dosing solenoid valve, water dosing solenoid valve, and stirrer, add the set amount of persulfate and water into the dissolving tank, stir with the stirrer, and the persulfate is fully dissolved in the water;

[0071] When Q3≥Q 设定3 , t = t 设定At this time, close the dosing solenoid valve, the water dosing solenoid valve, and the stirrer; the persulfate dissolution is complete.

[0072] When Q4 < Q 设定4 Open the sixth water pump 54, the twelfth valve 55 and the thirteenth valve 56 to send the prepared repair agent in the dissolving tank to the storage tank;

[0073] When Q4≥Q 设定4 Close the sixth water pump 54, the twelfth valve 55 and the thirteenth valve 56, and open the discharge pump 513, the fourteenth valve 514 and the fifteenth valve 515 to deliver the repair agent to the dosing pipeline.

[0074] The preparation of the repair agent is repeated in the dispensing unit.

[0075] When the solar heating unit starts, the actual water level detected by the water level sensor in the hot water collection tank is recorded as Q1, the first temperature detected by the first temperature detector in the hot water collection tank is recorded as T1, the real-time temperature detected in the contaminated soil is recorded as T3, the water temperature in the hot water supply tank is T2 and the water level is Q2, and the temperature inside the heat medium heating pipe is T4. Where T... 设定1 T 设定2 T 设定3 T 设定4 This is a set value, which can be set manually or by the user. Q 设定1 Based on the volume setting of the hot water tank, Q 设定2 Set according to the capacity of the hot water tank; T 设定1 T 设定2 The temperature is 40℃.

[0076] When Q1 < Q 设定1 The first water pump 19, the second water pump 112, the first valve 110 and the second valve 111, the third valve 113 and the fourth valve 114 are turned on to start water supply and solar heating.

[0077] When Q1≥Q 设定1 Close the first water pump 19, the second water pump 112, the first valve 110 and the second valve 111, the third valve 113 and the fourth valve 114 to end the water supply.

[0078] When T3 < T 设定3 , T1≥T 设定1 At that time, the fourth water pump 118, the seventh valve 119, the eighth valve 120, and the eleventh valve 124 are opened to supply the heated hot water in the hot water collection tank to the heat medium heating pipe.

[0079] When T3 > T 设定3 , T1≥T 设定1When the temperature of the soil to be repaired is sufficient to heat-activate the oxidizing agent, there is no need to supply hot water to the heating pipe of the heat medium. The fourth water pump 118, the seventh valve 119, the eighth valve 120, and the eleventh valve 124 are closed. The hot water generated by solar energy is stored in the hot water collection tank and the hot water supply tank.

[0080] When T3 < T 设定3 T1 < T 设定1 If the solar energy cannot heat the water to the set temperature, the third water pump 115, the fifth valve 116 and the sixth valve 117 are turned on to send the water in the hot water collection tank to the hot water supply tank. The electric heater is turned on to perform secondary heating and heat the water to the set temperature. Then the heated water is sent to the heat medium heating pipe.

[0081] When T3 < T 设定3 T1 < T 设定1 Q2 < Q 设定2 When the first water pump 19, the second water pump 112, the first valve 110 and the second valve 111, the third valve 113 and the fourth valve 114 are closed, and the third water pump 115, the fifth valve 116 and the sixth valve 117 are opened to supply water to the hot water tank.

[0082] When T3 < T 设定3 Q2≥Q 设定2 When T2 < T 设定2 Close the third water pump 115, the fifth valve 116, and the sixth valve 117, and turn on the electric heater for secondary heating; if T2 ≥ T 设定2 When the electric heater is turned off, the fourth water pump 118, the seventh valve 119 and the eighth valve 120 are turned on, and hot water enters the heat medium heating pipe.

[0083] When T4 < T 设定4 Then, the fifth water pump 121, the ninth valve 122, and the tenth valve 123 are turned on to return the water in the heat medium heating pipe to the hot water collection tank, and the solar heating is restarted.

[0084] When T4≥T 设定4 Close the fifth water pump 121, the ninth valve 122, and the tenth valve 123.

[0085] The set temperature of the heat transfer medium is increased every two hours, the change in contaminant concentration is monitored, a graph is generated, and the optimal heating temperature is selected. (See attached instruction manual.) Figure 2As shown, when the set temperature is 40℃, the degradation rate of naphthalene in the system is approximately 41.5% after 120 min of reaction. When the reaction temperature is increased to 50℃, 60℃, and 70℃, the degradation rate of naphthalene gradually increases to 60.5%, 66.7%, and 85.9%, respectively. With the increase of temperature, energy consumption also increases accordingly. When the temperature rises from 40℃ to 50℃, the degradation rate increases by 19%; from 50℃ to 60℃, the degradation rate increases by 6.2%; and from 60℃ to 70℃, the degradation rate increases by 19.2%.

[0086] Considering both the overall repair effect and energy saving, the optimal setting temperature for the heat medium, 50℃, was selected as the temperature with the highest ratio of degradation rate to power consumption. This optimal setting temperature was then fed back to the controller, and the temperature of the heat medium was adjusted to 50℃. 设定1 T 设定2 T 设定3 The temperature is set to 50℃, and the pressure setting in the multiphase extraction pipeline is increased accordingly to ensure that the reagent remains liquid and circulates in the system. The 50℃ setting is fed back to the control system to readjust the heating system's set temperature and ensure that the pollutant degradation rate remains within the set range. If the pollutant degradation rate is lower than the set range, the oxidation reaction rate between the remediation agent and the pollutants decreases, and the heat medium temperature is insufficient to meet the reaction conditions. In this case, the set temperature of the heat medium needs to be increased to keep the pollutant degradation rate within the set range.

[0087] When F = F 设定 When the pressure condition is met in the multiphase extraction pipeline, the vacuum pump continues to operate, promoting the oxidation reaction between the remediation agent and the contaminants. The detection device at the extraction well continuously monitors and collects the contaminant concentration. When the contaminant degradation rate decreases, the activation temperature of the remediation agent is increased, the temperature setpoint of the heating system is modified, and heating is restarted. The gas-liquid separator, the eighth water pump 712, the air pump 715, the oil-water separator, the twentieth valve 713, the twenty-first valve 714, the twenty-second valve 716, and the twenty-third valve 717 are activated to treat wastewater, exhaust gas, and collect hazardous waste.

[0088] Photoionization detectors (PID sensors) and rapid water quality analyzers are installed at the inlet and outlet of the end-of-pipe treatment device to monitor the discharged liquids and gases. If the discharge meets the emission standards, the liquids and gases are discharged; if they do not meet the emission standards, the liquids and gases are re-treated at the end of the pipe.

[0089] Example 2

[0090] As per the instruction manual Figure 1 As shown, the present invention also provides a solar thermal activated oxidation remediation system for contaminated soil, used to complete the remediation method described in Example 1, the system comprising:

[0091] A solar heating unit 1 is used for heating medium and storing heat medium. The solar heating unit is connected to a heat medium heating pipe 2 inserted into the contaminated soil.

[0092] The dosing unit 5 is used for the preparation and storage of remediation agents, and the dosing unit is connected to a dosing pipe 6 inserted into the contaminated soil.

[0093] Multiphase extraction unit 7, wherein the multiphase extraction unit 7 is connected to a multiphase extraction pipe 8 inserted into the contaminated soil;

[0094] The data acquisition unit includes a temperature detection device 3 and a pollutant detection device. The temperature detection device 3 is interlocked with the solar heating unit 1 to monitor the temperature of the contaminated soil and provide feedback to control the flow rate of the heating medium in the heating pipe 2. The pollutant detection device is interlocked with the solar heating unit 1 and the dosing unit 5 respectively to monitor the contamination status of the contaminated soil and provide feedback to control the set temperature of the heating medium in the solar heating unit and the preparation parameters of the remediation agent in the dosing unit.

[0095] The system also includes controller 4.

[0096] The solar heating unit 1, the heat medium heating pipe 2, the data acquisition unit, the dosing unit 5, the dosing pipe 6, the multiphase extraction unit 7, and the multiphase extraction pipe 8 can be found in Embodiment 1, and will not be described again here.

[0097] Those skilled in the art will understand that the present invention can be implemented in many other specific forms without departing from the spirit and scope of the invention. Although embodiments of the invention have been described, it should be understood that the invention is not limited to these embodiments, and those skilled in the art can make changes and modifications within the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for solar thermal activation and oxidation remediation of contaminated soil, characterized in that, Includes the following steps: The contamination status of the soil is detected, and the preparation parameters of the remediation agent and the set temperature of the heat medium used to heat the contaminated soil are determined based on the contamination status. The set temperature of the heat medium includes the initial set temperature of the heat medium, and the determination of the initial set temperature of the heat medium specifically includes: The types and concentrations of pollutants in contaminated soil are detected, and based on the test results, the types and concentrations of remediation agents used to remediate the contaminated soil, as well as the initial set temperature of the heat medium used to activate the remediation agents, are determined. The set temperature of the heat medium also includes the optimal set temperature of the heat medium, and the determination of the optimal set temperature of the heat medium specifically includes: The set temperature of the heat medium is adjusted every once in a while, and the pollution status data of the contaminated soil at the corresponding set temperature is collected. The degradation rate of pollutants, energy consumption, and the ratio of degradation rate to energy consumption are obtained through multiple sets of pollution status data. The set temperature of the heat medium with the largest ratio is selected as the optimal set temperature. This optimal set temperature is fed back to the solar heating unit, and the temperature of the heat medium introduced into the contaminated soil is adjusted to the optimal set temperature. The heat medium heated by the solar heating unit is introduced into the contaminated soil, and the temperature of the contaminated soil is monitored in real time. The amount of heat medium introduced is adjusted accordingly to maintain the internal temperature of the contaminated soil at the set temperature, which is equal to the set temperature of the heat medium. The prepared remediation agent is introduced into the contaminated soil, and multiphase extraction is performed on the contaminated soil. During the remediation process, the contamination status of the contaminated soil is monitored in real time, and the remediation agent preparation parameters and / or the set temperature of the heat medium are adjusted accordingly. The multiphase extraction pipeline is equipped with a pressure sensor to monitor the gas pressure inside the pipeline. The extraction pressure is higher than the vapor pressure of the remediation agent to ensure that the remediation agent remains liquid and circulates in the system. The vapor pressure of the remediation agent increases with the increase of the temperature of the heat medium, and the extraction pressure increases with the increase of the vapor pressure of the remediation agent to maintain the fluidity and extraction efficiency of the remediation agent. If the multiphase extraction pressure of the contaminated soil is less than the pressure set value, the multiphase extraction pressure is adjusted until the multiphase extraction pressure is greater than or equal to the pressure set value. Multiphase extraction is continued for a period of time. The extraction pressure also has a maximum set threshold. The pressure in the multiphase extraction pipeline is less than the maximum set threshold.

2. The method for solar thermal activation oxidation remediation of contaminated soil according to claim 1, characterized in that, Real-time monitoring of soil contamination includes: Based on real-time monitoring results of pollution, the concentration of remediation agents introduced into the polluted soil is adjusted. When the pollutant degradation rate is detected to be less than the set range for a certain period of time, the set temperature of the heat medium introduced into the polluted soil is increased.

3. The method for solar thermal activation oxidation remediation of contaminated soil according to claim 1, characterized in that, If the temperature of the contaminated soil is less than the set temperature of the heat medium, the solar heating unit supplies heat medium to the contaminated soil until the temperature of the contaminated soil is not lower than the set temperature of the heat medium; if the temperature of the contaminated soil is greater than or equal to the set temperature of the heat medium, the solar heating unit stops supplying heat medium to the contaminated soil, and the heat medium is stored and kept warm in the solar heating unit.

4. The method for solar thermal activation oxidation remediation of contaminated soil according to claim 3, characterized in that, The solar heating unit includes a solar heating component and a storage component for storing a heat medium. The storage component is connected to the solar heating component. If the heating temperature of the solar heating component is greater than or equal to the set temperature of the heat medium, the heat medium heated to the set temperature is sent to the storage component for storage and later use. If the heating temperature of the solar heating component is less than the set temperature of the heat medium, the heat medium in the storage component is heated to the set temperature.

5. The method for solar thermal activation oxidation remediation of contaminated soil according to claim 1, characterized in that, If the pollutant concentration in the contaminated soil is detected to be greater than the pollutant concentration control value, the prepared remediation agent will be delivered to the contaminated soil to react with the pollutants in the soil through oxidation. If the pollutant concentration in the contaminated soil is detected to be less than or equal to the pollutant concentration control value, the delivery of the remediation agent and the delivery of the heat medium to the contaminated soil will be stopped.

6. The method for solar thermal activation oxidation remediation of contaminated soil according to claim 1, characterized in that, The waste gas and wastewater collected by multiphase extraction of the contaminated soil are purified and then discharged.

Images