Self-powered ambient air and soil gas in-situ sampling and combined online monitoring system

Abstract

The invention relates to a self-energized ambient air and soil gas in-situ sampling and combined online monitoring system, which realizes in-situ combined sampling and online monitoring of volatile organic compounds in different media by integrating ambient air and soil gas sampling modules. The key problems that a soil gas on-line monitoring technology is lacked and the volatile organic compounds in the soil gas cannot be supported to invade ambient air monitoring and early warning are solved, multi-medium synchronous on-line monitoring and efficient early warning response of the volatile organic compounds are realized, and the intelligent monitoring level of the soil environment is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of environmental monitoring technology, specifically to a self-powered in-situ sampling and combined online monitoring system for ambient air and soil gas. Background Technology

[0002] In the field of environmental monitoring, monitoring volatile organic compounds (VOCs) in soil gas is crucial for assessing soil pollution, predicting pollutant migration trends, and protecting human health. However, soil gas monitoring is affected by various meteorological conditions, such as temperature, humidity, and light intensity, which directly influence the volatilization, diffusion, and migration of pollutants in the soil. Meanwhile, soil gas intrusion into ambient air, especially in and around industrial pollution sites with concentrated and high concentrations of pollutants, has become an increasingly serious environmental problem, posing potential risks to ecosystems and human health.

[0003] Pollutants in soil gas originate from the volatilization of pollutants in soil and groundwater. The three-phase balance of water, air, and soil in the soil environment directly affects the composition and structure of soil gas, and its components are significantly influenced by meteorological conditions such as temperature and humidity. Increased temperature can accelerate the volatilization of organic pollutants, while changes in humidity affect soil permeability and gas solubility. Changes in light intensity may also affect soil microbial activity, thereby affecting soil gas production. These factors work together to cause dynamic changes in the monitoring values ​​of volatile organic compounds (VOCs) in soil gas, increasing the complexity of monitoring. Pollutants in soil gas, especially VOCs, may enter the ambient air through soil pores and cracks under suitable meteorological conditions, potentially leading to a decline in outdoor air quality, affecting ecosystem balance, and in some cases, impacting human health through inhalation and oral ingestion.

[0004] Current monitoring technologies have several limitations: Soil gas monitoring is currently limited to manual sampling and laboratory testing, lacking real-time online monitoring. Considering the dynamic migration characteristics of volatile organic compounds in soil gas, manual sampling and testing cannot provide monitoring and early warning functions. While online monitoring of ambient air is widely used, current technologies have not yet been applied to soil environmental monitoring. This results in insufficient monitoring capabilities for soil pollution sources and a lack of monitoring data. Existing soil gas sampling and monitoring methods cannot support the dynamic migration and interaction of pollutants between soil gas and ambient air, and are insufficient to provide effective monitoring, early warning, and solutions for soil gas intrusion problems.

[0005] With increasingly stringent environmental protection regulations, the requirements for soil gas monitoring and ambient air quality are also constantly increasing. Monitoring equipment is required to not only accurately reflect the concentration levels of pollutants in soil gas, but also to monitor ambient air quality in real time in order to promptly detect and respond to soil gas intrusion problems. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a self-powered in-situ sampling and joint online monitoring system for ambient air and soil gas. By integrating ambient air and soil gas sampling modules, it enables in-situ joint sampling and online monitoring of volatile organic compounds (VOCs) in different media, thereby solving the key problem of the lack of online soil gas monitoring technology and the inability to support the monitoring and early warning of VOCs in soil gas intruding into ambient air.

[0007] A self-powered in-situ sampling and joint online monitoring system for ambient air and soil gas includes an ambient air sampling module, a soil gas sampling module, a detection module, a central processing unit, a data transmission module, and a power supply module, wherein: The ambient air sampling module has a high-efficiency air filter component at its front end, used to remove particulate matter and moisture; then it is connected to a solenoid valve to control the opening and closing of the air path; then it is connected to an air path distributor, which connects the air inlets of multiple air path channels to the distributor; then it is connected to a vacuum pump to draw in ambient air; the high-efficiency air filter component has a filter body at its upper part; the filter body is funnel-shaped and has replaceable filter cotton inside; after the filter cotton, an electronic flow meter is connected to control the airflow rate; The soil gas sampling module is connected at the front end to a soil gas probe buried underground, and then connected to a solenoid valve through a gas path; then connected to a vacuum pump to provide negative pressure; The detection module is located in the gas chamber and uses photoionization sensors and electrochemical sensors to detect the concentration data of volatile organic compounds and conventional environmental factors in ambient air and soil gas. The central processing unit controls the operation of the vacuum pump and performs data reading and analysis, including time-series analysis of ambient air and soil gas. The data transmission module is responsible for wirelessly transmitting the data analyzed by the central processing unit to the remote monitoring center, enabling remote real-time monitoring and analysis of the data.

[0008] Furthermore, before each sampling, the ambient air sampling module and the soil gas sampling module set a settling time through the central processing unit, and purge the gas path and gas chamber with clean air to remove residual gas from the previous sampling.

[0009] Furthermore, the detection module uses photoionization sensors and electrochemical sensors to detect the concentration of volatile organic compounds in ambient air and soil gas, as well as environmental factors such as temperature, humidity, air pressure, and wind speed.

[0010] Furthermore, the data parsing algorithm of the central processing unit includes the following steps: First, sample n times for each channel and calculate the standard deviation S and mean value of each sensor response value v. The data sequence is cleaned using the z-score, and the average of the remaining sequences is taken as the final value. The z-score calculation formula is as follows: , Then, a decoupling algorithm is used to calculate the concentration of each factor: , in For the first i The final value of each sensor, m For the number of sensors, m It is also equal to the quantity of the gas to be tested. For the first j The unit concentration of the gas factor caused by the first i Sensor response values ​​(from sensor manual) The first one to be solved j The actual concentrations of the gases can be obtained by solving this system of linear equations:

[0011] The response coefficients of each sensor are nonlinearly correlated, therefore the coefficient matrix is ​​invertible. Finally, the concentrations of each gas factor were obtained through decoupling calculations. and the constant olfaction threshold of each gas factor Calculate the dimensionless OU value of a gas:

[0012] Furthermore, the system also includes a solar self-powered module, which automatically controls the charging and discharging functions of the solar panels and batteries by a charging controller, ensuring stable power supply and providing overcharge protection, thus enabling the system to operate stably in the field for a long time.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. By coupling in-situ sampling and online monitoring methods for ambient air and soil gas, a specially designed approach is developed based on traditional manual soil gas sampling technology and ambient air online monitoring technology. This approach can effectively achieve in-situ joint sampling and online monitoring of ambient air and soil gas, solving the problems of difficulty in observing the source of soil pollution release by single-medium ambient air online monitoring and the lack of real-time online monitoring means for manual soil gas detection.

[0014] 2. By embedding data parsing algorithms into the central processing unit, a central control system based on effective monitoring data analysis methods is formed, which improves the overall reliability of the data and gives the system a certain ability to self-diagnose and self-repair, overcoming the drawbacks of serial detection systems that rely solely on simple hardware stacking.

[0015] 3. By equipping the system with a solar self-powered module, the online monitoring system can achieve long-term stable operation of field sampling and monitoring, solving the practical problems of difficulty in connecting to the mains power, difficulty in stable operation and maintenance, and the risk of damage and leakage in contaminated sites under field conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the self-powered ambient air and soil gas in-situ sampling and joint online monitoring system provided by the present invention. Figure 2 This is a schematic diagram of the structure of the filter of the present invention; Figure 3 A schematic diagram of the internal process structure of the self-powered ambient air and soil gas in-situ sampling and joint online monitoring system provided by the present invention; Figure 4 A graph showing the data from online soil gas monitoring; Figure 5 A graph showing the relationship between online soil gas monitoring data and PID rapid measurement data; In the diagram: 1. Ambient air sampling module; 2. Soil gas sampling module; 3. Detection module; 4. Central processing unit; 5. Data transmission module; 6. Power supply module; 7. High-efficiency air filter assembly; 8. Solenoid valve; 9. Gas path; 10. Gas path distributor; 11. Vacuum pump; 12. Soil gas probe; 13. Gas chamber; 14. Photoionization sensor; 15. Electrochemical sensor; 16. Charging controller; 17. Control solar panel; 18. Battery; 19. Filter body; 20. Filter cotton; 21. Electronic flow meter; 22. Display screen; 23. Housing; 24. Bracket; 25. Base; 26. Soil gas monitoring well. Detailed Implementation

[0017] This invention provides a self-powered in-situ sampling and joint online monitoring system for ambient air and soil gas. The integrated ambient air and soil gas in-situ sampling modules share the same gas chamber but use different sampling channels and independent gas paths. A central processing unit centrally controls the switching of the gas paths, the operation of the vacuum pump, and data analysis. The basic principle of data analysis is to ensure the stability of the detection results through time-series analysis of ambient air and soil gas, thereby guaranteeing data reliability. The ambient air sampling module has a high-efficiency air filter at the front end to remove particulate matter and moisture; it is then connected to a solenoid valve to control the opening and closing of the gas path; subsequently, it connects to a gas distributor, which unifies the air inlets of multiple gas paths; and finally, it connects to a vacuum pump to extract ambient air. The soil gas sampling module has a soil gas probe buried underground at the front end, which is then connected to a solenoid valve via a gas path; finally, it connects to a vacuum pump to provide negative pressure.

[0018] like Figure 1 and 3 As shown, a self-powered in-situ sampling and joint online monitoring system for ambient air and soil gas includes: an ambient air sampling module 1, a soil gas sampling module 2, a detection module 3, a central processing unit 4, a data transmission module 5, and a power supply module 6.

[0019] The ambient air sampling module 1 has a high-efficiency air filter component 7 at its front end to remove particulate matter and moisture; then it is connected to a solenoid valve 8 to control the opening and closing of the air passage 9; then it is connected to an air distributor 10, which connects the air inlets of multiple air passages 9 to the distributor; then it is connected to a vacuum pump 11 to extract ambient air. The soil gas sampling module 2 has a soil gas probe 12 buried underground at its front end, then it is connected to the solenoid valve 8 through the air passage 9; then it is connected to the vacuum pump 11 to provide negative pressure. The detection module 3 is located in the gas chamber 13 and uses a photoionization sensor 14 and an electrochemical sensor 15 to detect the concentration data of volatile organic compounds and conventional environmental factors in ambient air and soil gas. The central processing unit 4 centrally controls the operation of the vacuum pump 11 and performs data reading and analysis. The basic principle of data analysis is to ensure the stability of detection through time series analysis of ambient air and soil gas, thereby determining the reliability of the data; the analyzed data can be displayed on the display screen 22 in real time. The data transmission module 5 is responsible for wirelessly transmitting the data analyzed by the central processing unit 4 to the remote monitoring center, enabling remote real-time monitoring and analysis of the data. The power supply module 6 is connected to and controls the solar panel 17, the battery 18, and the equipment load via the charging controller 16, ensuring a stable power supply.

[0020] The system includes an ambient air sampling module 1 and a soil gas sampling module 2. The two sampling modules share a detection module 3, a central processing unit 4, a data transmission module 5, and a power supply module 6. The soil gas probe 12 is connected to a solenoid valve 8 via a gas path 9. The ambient air and soil gas samples collected by the ambient air sampling module 1 and the soil gas sampling module 2 enter the gas chamber 13, which is a cylindrical gas storage device.

[0021] Before each sampling, the ambient air sampling module 1 and the soil gas sampling module 2, in order to avoid mutual interference between gases in different environmental media, set a settling time through the central processing unit 4, and use clean air to purge the gas path 9 and the gas chamber 13 to remove the residual gas from the previous sample injection, thereby achieving a cleaning effect and ensuring the accuracy of the test results.

[0022] like Figure 2 As shown, the upper part of the high-efficiency air filter assembly 7 is provided with a filter body 19; the filter body is funnel-shaped and has a replaceable filter cotton 20 inside; an electronic flow meter 21 is connected to the filter cotton to control the airflow speed.

[0023] The central processing unit 4 is the core of the entire monitoring system. It incorporates advanced data analysis algorithms, enabling rapid and accurate analysis of the collected gas samples, stable overall operation of the equipment, and the completion of pre-set actions to achieve a series of objectives such as sampling, detection, and data processing. The data obtained by the central processing unit 4 can be displayed in real time on the display screen 22.

[0024] The data parsing algorithm first performs n samplings for each channel and calculates the standard deviation S and average value of each sensor response value v. The data sequence is cleaned using the z-score, and the average of the remaining sequences is taken as the final value. The z-score calculation formula is as follows: , Then, a decoupling algorithm is used to calculate the concentration of each factor: , in For the first i The final value of each sensor, m The number of sensors is equal to the number of gases being measured. For the first j The concentration of the gaseous factor caused the first i Sensor response values ​​(from sensor manual) The first one to be solved j The actual concentration of each gas. Solving this system of linear equations yields the actual concentration of each gas factor: , The response coefficients of each sensor are nonlinearly correlated, therefore the coefficient matrix is ​​invertible.

[0025] Finally, the concentrations of each gas factor were obtained through decoupling calculations. and the olfaction threshold of each gaseous factor Calculate the OU value (dimensionless) for a gas: , The solar panel 17 charges the battery 18 through the charging controller 16, and the battery 18 supplies power to the monitoring equipment through the charging controller 16. The charging controller 16 automatically controls the charging and discharging function of the battery to ensure stable power supply and provide overcharge protection.

[0026] This invention discloses a self-powered in-situ sampling and joint online monitoring system for ambient air and soil gas. Its sampling module collects ambient air and soil gas through an automatically controlled multi-channel high-efficiency filtration device, effectively addressing the differences in technical requirements for gas collection, drying, and filtration in different media. The detection module integrates multiple sensors to monitor environmental factors such as temperature, humidity, air pressure, and wind speed, as well as volatile organic compounds (VOCs) in real time. The central processing unit implements automated control and data processing algorithms. The data transmission module supports wireless communication for remote monitoring. The power supply module, equipped with a photovoltaic self-powered device, ensures long-term stable operation of the monitoring system in the field. This invention achieves multi-media synchronous online monitoring and efficient early warning response for VOCs, effectively improving the level of intelligent soil environmental monitoring.

[0027] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed description of a self-powered in-situ sampling and combined online monitoring system for ambient air and soil gas according to the present invention: Example: Operational process of in-situ sampling and joint online monitoring of ambient air and soil gas at a pesticide-contaminated site.

[0028] like Figures 1-3As shown, this embodiment provides a self-powered in-situ sampling and joint online monitoring system for ambient air and soil gas. The system is configured with 6 underground soil gas channels and 1 air channel. It detects environmental factors including temperature, humidity, air pressure, and wind speed, and volatile organic compounds including TVOC, H2S, NH3, CH3SH, and OU. The number and type of sensors can be set according to actual needs. The system includes an ambient air sampling module 1, a soil gas sampling module 2, a detection module 3, a central processing unit 4, a data transmission module 5, and a power supply module 6. Regarding the operation process of ambient air in-situ sampling and online monitoring, firstly, the air solenoid valve 8 is opened to connect the air channel, other channels are closed, and the confluence channel before entering the gas chamber 13 is cleaned. Then, ambient air samples are collected. The front end of the ambient air sampling module 1 is a high-efficiency air filter component 7, used to remove particulate matter and moisture from the ambient air. It is then connected to the solenoid valve 8, which is connected to the gas distributor 10. The solenoid valve 8 controls the opening of the ambient air gas path 9, and the ambient air is drawn by the vacuum pump 11 connected to the gas distributor 10. The extracted air enters the gas distributor 10 through gas path 9 and finally enters the detection module 3. After sampling and detection, the solenoid valve 8 is closed. The detection module 3 uses a photoionization sensor 14 and an electrochemical sensor 15 to detect the concentration of volatile organic compounds and environmental factors in the ambient air. Then, it sequentially switches to other soil gas channels for in-situ soil gas sampling and online monitoring. First, the air solenoid valve 8 is opened to connect the air channel, and other channels are closed to clean the confluence channel before entering the gas chamber 13. Then, the air channel is closed, and the soil gas sampling channel, such as gas path 9, is opened for well cleaning. The well cleaning time = 3 × (gas pipe volume + soil gas probe volume) ÷ flow rate. After that, sampling and detection are performed. Other operating procedures are the same as those for in-situ ambient air sampling and online monitoring, and the two can be performed alternately. The central processing unit 4 reads and parses the data twice. The basic principle of data parsing is to use time-series analysis of ambient air, clean the data using the z-score method, calculate the concentration of each factor using a decoupling algorithm, and calculate the OU value using the calculated factor concentrations and olfaction threshold to ensure the stability of the detection results and thus guarantee the reliability of the data. The parsed data is displayed on the display screen 22. The data transmission module 5 is responsible for wirelessly transmitting the data parsed by the central processing unit 4 to the remote monitoring center, realizing remote real-time monitoring and analysis of the data.

[0029] In practical use, the solar panel 17 is fixed to a pole, which is then fixed to a cement platform on the ground. The solar panel 17 is connected to a charging controller 16, which is connected to the power interfaces of the battery 18 and the central processing unit 4 of the monitoring system to enable the device to be self-powered. Part of the gas path 9 is exposed to the ambient air above ground (the other part of the gas path is buried at different depths in the soil gas monitoring well). The ambient air enters the high-efficiency air filter assembly 7, flows through the filter body 19 and the filter cotton 20 in sequence to remove particulate matter and moisture from the ambient air; it is then connected to the solenoid valve 8 through the gas path 9; then to the gas distributor 10; and then to the vacuum pump 11 to draw in the ambient air and store it in the gas chamber 13. The concentration data of the gas is detected by the photoionization sensor 14 and the electrochemical sensor 15. The central processing unit 4 is the core of the entire monitoring system. It has an advanced data analysis algorithm built in, which can quickly and accurately analyze the collected ambient air samples and display them on the display screen 22; finally, the data transmission module 5 is responsible for transmitting the data wirelessly to the remote monitoring center, realizing remote real-time monitoring and analysis of the data.

[0030] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; those skilled in the art can still make changes, modifications, substitutions and variations to the technical solutions described in the foregoing embodiments, without causing the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and all of them should be covered within the scope of the claims and specification of the present invention.

Claims

1. A self-powered in-situ sampling and joint online monitoring system for ambient air and soil gas, comprising an ambient air sampling module, a soil gas sampling module, a detection module, a central processing unit, a data transmission module, and a power supply module, characterized in that: The ambient air sampling module has a high-efficiency air filter component at its front end, used to remove particulate matter and moisture; then it is connected to a solenoid valve to control the opening and closing of the air path; then it is connected to an air path distributor, which connects the air inlets of multiple air path channels to the distributor; then it is connected to a vacuum pump to draw in ambient air; the high-efficiency air filter component has a filter body at its upper part; the filter body is funnel-shaped and has replaceable filter cotton inside; after the filter cotton, an electronic flow meter is connected to control the airflow rate; The soil gas sampling module is connected at the front end to a soil gas probe buried underground, and then connected to a solenoid valve through a gas path. It is then connected to a vacuum pump to provide negative pressure; The detection module is located in the gas chamber and uses photoionization sensors and electrochemical sensors to detect the concentration data of volatile organic compounds and conventional environmental factors in ambient air and soil gas. The central processing unit controls the operation of the vacuum pump and performs data reading and analysis, including time-series analysis of ambient air and soil gas. The data transmission module is responsible for wirelessly transmitting the data analyzed by the central processing unit to the remote monitoring center, enabling remote real-time monitoring and analysis of the data.

2. The self-powered in-situ sampling and joint online monitoring system for ambient air and soil gas according to claim 1, characterized in that: Before each sampling, the ambient air sampling module and the soil gas sampling module set a settling time through the central processing unit, and purge the gas path and gas chamber with clean air to remove residual gas from the previous sample injection.

3. The self-powered in-situ sampling and joint online monitoring system for ambient air and soil gas according to claim 1, characterized in that: The detection module uses photoionization sensors and electrochemical sensors to detect the concentration of volatile organic compounds in ambient air and soil gas, as well as environmental factors such as temperature, humidity, air pressure, and wind speed.

4. The self-powered ambient air and soil gas in-situ sampling and joint online monitoring system according to any one of claims 1 to 3, characterized in that: The data parsing algorithm of the central processing unit includes the following steps: First, sample n times for each channel and calculate the standard deviation S and mean value of each sensor response value v. The data sequence is cleaned using the z-score, and the average of the remaining sequences is taken as the final value. The z-score calculation formula is as follows: , Then, a decoupling algorithm is used to calculate the concentration of each factor: , in For the first The final value of each sensor, m For the number of sensors, m It is also equal to the quantity of the gas to be tested. For the first j The unit concentration of the gas factor caused by the first i Sensor response values ​​(from sensor manual) The first one to be solved j The actual concentrations of the gases can be obtained by solving this system of linear equations: , The response coefficients of each sensor are nonlinearly correlated, therefore the coefficient matrix is ​​invertible. Finally, the concentrations of each gas factor were obtained through decoupling calculations. and the constant olfaction threshold of each gas factor Calculate the dimensionless OU value of a gas: 。 5. The self-powered in-situ sampling and joint online monitoring system for ambient air and soil gas according to claim 4, characterized in that: It also includes a solar self-powered module, which automatically controls the charging and discharging functions of the solar panels and batteries by a charging controller, ensuring stable power supply and providing overcharge protection, so as to achieve long-term stable operation of the system in the field.

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