A Real-Time Landfill Leakage Monitoring System Based on Megohm Resistivity Method

Abstract

This invention discloses a real-time landfill leakage monitoring system based on the megohm resistivity method. The system includes monitoring electrodes and temperature sensors arranged in an array on both the inner and outer sides of a landfill geomembrane. A local processing platform includes a power supply and a microcontroller that communicates with the sensors on the membrane. The power supply is electrically connected to the monitoring electrodes on both sides of the landfill geomembrane via the microcontroller's high-voltage module. The microcontroller communicates with both the monitoring electrodes and the temperature sensors to receive the resistance value between the inner and outer sides of the landfill geomembrane and the temperature difference between them. An online cloud platform communicates with the microcontroller to receive and store real-time data on the resistance value and temperature difference between the inner and outer sides of the landfill geomembrane. A user terminal communicates with the online cloud platform. This invention utilizes both resistance and temperature as dual detection parameters to trigger the leakage determination condition of the geomembrane, improving the problem of data simplification and enhancing the accuracy and stability of real-time landfill leakage monitoring results.

Description

Technical Field

[0001] This utility model relates to a real-time monitoring system for landfill leakage based on the megohm resistivity method, which belongs to the landfill monitoring technology through electrical exploration. Background Technology

[0002] Landfills use geomembrane linings to separate the landfill pit from the underground soil, preventing the landfill waste and its leachate from seeping into the underground soil. However, with the increasing volume of landfills, external forces during the landfill process or the heat generated by chemical reactions within the landfill waste can damage the geomembrane lining, leading to leakage of the landfill waste. Therefore, landfills need to monitor the geomembrane leakage in real time.

[0003] Most existing geomembrane leakage monitoring technologies and equipment employ electrical resistivity tomography (EDT) to collect electrical signals inside and outside the geomembrane lining of landfills. The changes in these electrical signals after leakage are then used to monitor the leakage. While this monitoring method can detect geomembrane leakage to some extent, it still has the following shortcomings: Limitations of detection mechanisms and data interpretation. Traditional technologies may rely on changes in a single physical quantity (such as resistance value alone) or on relatively coarse threshold judgments, such as the rapid location device for landfill leakage disclosed in Chinese patent application CN201922309109.4. This may lead to a high false alarm rate in complex environments or insensitivity to early and weak leakage. The interpretation and analysis of the collected electrical signal data often require on-site judgment by professionals, lacking intelligent and standardized processing procedures.

[0004] Data acquisition and processing are often delayed and costly. Traditional equipment mostly stores data offline or locally, requiring manual on-site collection periodically. This not only results in poor real-time monitoring data, making it impossible to detect and respond to leakage events in a timely manner, but also significantly increases manpower, material resources, and time costs. Summary of the Invention

[0005] The technical problem solved by this utility model is to provide a new real-time monitoring system for landfill leakage based on the megohm resistivity method, which addresses the problem of low detection accuracy due to the single data acquisition method in existing landfill leakage monitoring technologies.

[0006] This utility model is achieved using the following technical solution: A real-time monitoring system for landfill leakage based on the megohm resistivity method includes: The membrane sensor 200 includes monitoring electrodes 201 and temperature sensors 202 arranged in an array on both the inside and outside of the landfill geomembrane. A set of monitoring electrodes (201) and a set of temperature sensors (202) are respectively arranged on the inside and outside of the geomembrane at the same location. The local processing platform 300 includes a power supply 320 and a microcontroller 310 that is communicatively connected to the sensors on the membrane. The power supply 320 is electrically connected to the monitoring electrodes 201 on both the inside and outside of the landfill geomembrane through the high voltage module of the microcontroller 310. The microcontroller 310 is communicatively connected to the monitoring electrodes 201 and the temperature sensor 202 respectively. It receives the voltage and current signals through the monitoring electrodes to obtain the resistance value between the inside and outside of the landfill geomembrane and the temperature difference between the inside and outside of the landfill geomembrane detected by the temperature sensor. The online cloud platform 400 communicates with the microcontroller 310 to receive and store real-time data on the resistance value and temperature difference between the inside and outside of the geomembrane in the landfill. Several user terminals (500) communicate with the online cloud platform (400).

[0007] In a real-time monitoring system for landfill leakage based on the megohm resistivity method of this utility model, the landfill geomembrane further includes a main geomembrane 101 and a secondary geomembrane 102 laid overlapping from top to bottom. The monitoring electrode 201 and temperature sensor 202 inside the membrane are arranged between the main geomembrane 101 and the secondary geomembrane 102, and the monitoring electrode 201 and temperature sensor 202 outside the membrane are arranged on the outside of the secondary geomembrane 102.

[0008] In a real-time monitoring system for landfill leakage based on the megohm resistivity method of this utility model, the monitoring electrode 201 and the temperature sensor 202 are further fixed to the landfill geomembrane by a sealing flange made of insulating material, and the sensor probes of the monitoring electrode 201 and the temperature sensor 202 directly contact the medium on both sides of the membrane.

[0009] In a real-time monitoring system for landfill leakage based on the megohm resistivity method of this utility model, the power supply 320 is a rechargeable power supply with a mains charging port 321 and a solar charging port 322, which are electrically connected to the mains power grid and the solar panel respectively, and the power supply is provided by a combination of solar and mains power.

[0010] In a real-time monitoring system for landfill leakage based on the megohm resistivity method of this utility model, the local processing platform 300 further includes a power display screen 340 for displaying power levels.

[0011] In a real-time monitoring system for landfill leakage based on the megohm resistivity method of this utility model, the local processing platform 300 further includes a local storage module 330. The local storage module 330 is communicatively connected to the microcontroller 310 and locally stores the resistance value between the inside and outside of the landfill geomembrane obtained from the voltage and current signals of the monitoring electrodes, as well as the temperature difference between the inside and outside of the landfill geomembrane detected by the temperature sensor.

[0012] In a real-time monitoring system for landfill leakage based on the megohm resistivity method of this utility model, the online cloud platform 400 further includes a cloud server for processing real-time data on the resistance value and temperature difference between the inside and outside of the landfill geomembrane, and a cloud storage for storing the real-time data on the resistance value and temperature difference between the inside and outside of the landfill geomembrane.

[0013] In the landfill leakage real-time monitoring system based on megohm resistivity method of this utility model, the online cloud platform 400 and the microcontroller 310 are further connected by 485 wired communication or WiFi wireless communication.

[0014] In a real-time monitoring system for landfill leakage based on the megohm resistivity method of this utility model, the user terminal 500 is further equipped with an alarm module to provide alarm reminders for changes in the resistance value and / or temperature difference between the inside and outside of the landfill geomembrane.

[0015] This invention utilizes the fact that when a geomembrane leaks in a landfill, the conductive medium (leachate) between the membranes causes a sharp drop in resistance (<1MΩ) across the geomembrane, while simultaneously increasing the local temperature rise on both sides of the membrane (ΔT ≥5℃). By using both resistance and temperature as dual detection parameters to trigger the leakage determination criteria for the geomembrane, this invention offers the following advantages: (1) This utility model adopts a dual-parameter coupling detection mechanism to simultaneously measure the temperature difference and resistivity difference between the inside and outside of the geomembrane. It judges leakage by the resistance change between the geomembranes and the abnormal temperature inside and outside the membrane. Combined with the conduction phenomenon of the monitoring electrodes on both sides of the membrane caused by membrane damage, it achieves dual verification. The resistance measurement between the two sides of the geomembrane is innovatively measured indirectly by a high-voltage module. The high-voltage module of the single-chip microcomputer applies high voltage to the monitoring electrode and calculates the resistance value by Ohm's law. Temperature monitoring is achieved by using a high-precision temperature sensor to capture the temperature change on both sides of the geomembrane in real time, which serves as an auxiliary criterion for leakage. It can more accurately reflect the characteristic data of geomembrane leakage filling, and is more accurate and sensitive for landfill leakage monitoring.

[0016] (2) While processing the resistance value and temperature difference data between the inside and outside of the geomembrane in the landfill using the local processing platform, this utility model also uploads the data to the online cloud platform. The online cloud platform can perform more analysis and processing on the real-time data collected by the local processing platform. At the same time, the data can be transmitted to multiple user terminals through Internet of Things technology, realizing remote professional data processing. It does not require professionals to monitor the site in real time, and it is more convenient to respond to and process abnormal data situations quickly.

[0017] (3) This utility model is powered by a rechargeable power supply and supports dual power supply of solar energy and mains power. It can choose to be powered by the mains power grid or solar power generation, reducing the dependence on a single power source and ensuring the continuous operation of the monitoring system.

[0018] In summary, the landfill leakage real-time monitoring system based on the megohm resistivity method provided by this utility model improves the problem of data uniformity in existing electrical exploration, enhances the accuracy and stability of real-time monitoring results of landfill leakage, and is more convenient and flexible to operate, which is conducive to the promotion and use of landfill technology.

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an overall system for real-time monitoring of landfill leakage based on the megohm resistivity method, as an example.

[0021] Figure 2 The data processing flowchart of the landfill leakage real-time monitoring system is shown in the example.

[0022] The diagram labels are: 101 - main geomembrane, 102 - secondary geomembrane, 103 - leachate; 200 - On-membrane sensor, 201 - Monitoring electrode, 202 - Temperature sensor; 300-Local processing platform, 310-Microcontroller, 320-Power supply, 321-Main power charging port, 322-Solar charging port, 330-Local storage module, 340-Power display screen; 400-Online Cloud Platform 500 - Client. Detailed Implementation

[0023] Example

[0024] See Figure 1 The illustrated landfill leakage real-time monitoring system based on megohm resistivity method is a specific implementation of this utility model, specifically including a membrane sensor 200, a local processing platform 300, an online cloud platform 400, and several user terminals 500.

[0025] The membrane sensor 200 includes a monitoring electrode 201 for detecting the resistance between the inside and outside of the geomembrane and a temperature sensor 202 for detecting the temperature difference between the inside and outside of the geomembrane. The monitoring electrode 201 and the temperature sensor 202 are arranged in an array on both sides of the geomembrane. The local processing platform 300 includes a power supply 320 and a microcontroller 310 that communicates with the membrane sensor. The power supply 320 is electrically connected to the monitoring electrode 201 on both sides of the landfill geomembrane through the high voltage module of the microcontroller 310. The microcontroller 310 communicates with the monitoring electrode 201 and the temperature sensor 202. The signal input ports A and C of the microcontroller 310 receive the voltage and current signals passing through the monitoring electrode and calculate the resistance between the inside and outside of the landfill geomembrane using Ohm's law. The signal input ports B and D of the microcontroller 310 receive the temperatures on both sides of the landfill geomembrane detected by the temperature sensor and calculate the temperature difference between the inside and outside of the landfill geomembrane.

[0026] The landfill geomembrane consists of a main geomembrane 101 and a secondary geomembrane 102, laid overlapping from top to bottom. Two layers of geotextile are sandwiched with sodium-based bentonite to form a bentonite waterproof blanket. Upon contact with water, the bentonite expands to form a low-permeability gel layer, which can resist leakage from initial damage to the main geomembrane. Leakage occurs when the secondary geomembrane 102 also breaks down, indicating that the entire landfill geomembrane is leaking. Monitoring electrodes 201 and temperature sensors 202 are located inside the membrane between the main geomembrane 101 and the secondary geomembrane 102, while the monitoring electrodes 201 and temperature sensors 202 are located outside the secondary geomembrane 102. Leakage of the geomembrane in the landfill occurs because the temperature inside the membrane rises sharply, causing a hole in the membrane. When the secondary geomembrane below the two layers of geomembrane also breaks, the leachate 103 inside the membrane leaks through the hole into the soil layer below the geomembrane. The monitoring electrodes 201 on both the inside and outside of the membrane are conductive and can measure a resistance value of less than 1 MΩ. In this embodiment, leakage is determined by measuring the temperature and resistance value inside and outside the membrane.

[0027] Power supply 320 outputs a 500V DC voltage through the high-voltage module of microcontroller 310, which is applied to the monitoring electrodes 201 on both sides of the geomembrane. Based on Ohm's law, resistance is calculated using a current with a range of 0.1μA - 1mA and a measurement accuracy of ±0.5%, covering a resistance calculation range of 0.1MΩ - 10GΩ. Temperature-assisted verification utilizes a PT100 temperature sensor with an accuracy of ±0.1℃ to monitor the inter-membrane temperature in real time, using a sudden temperature rise during leakage as a supplementary criterion for leakage detection. Using the resistance threshold method as the core indicator, the insulation resistance between the two sides of the geomembrane is greater than 100MΩ when there is no leakage. A resistance value between 3000kΩ and 10700kΩ is considered a possible leakage, while a value less than 3000kΩ is confirmed as leakage. Simultaneously, temperature is used as an auxiliary verification parameter, as the leachate temperature during leakage is typically higher than the ambient temperature (typical temperature difference ≥5℃), and an alarm is triggered when the temperature gradient exceeds 2℃ / min. In this embodiment, the monitoring electrode 201 does not directly measure the resistance between the inside and outside of the geomembrane. Instead, a power supply is connected to the monitoring electrode 201 via a high-voltage module (output 500V DC, current ≤1mA) on the microcontroller, providing voltage across the geomembrane. The microcontroller's integrated current detection module records the current flowing through the monitoring electrode 201, and the resistance between the inside and outside of the geomembrane is calculated using Ohm's law. The resistance calculation process is implemented through microcontroller programming. Both microcontroller programming and Ohm's law are existing well-known technologies and will not be elaborated upon in this embodiment.

[0028] The monitoring electrode 201 and temperature sensor 202 are fixed to the landfill geomembrane by a sealing flange. The sealing flange is made of insulating material such as fluororubber. The distance between the monitoring electrode 201 and temperature sensor 202 on the same side of the membrane is ≤5cm to ensure that the sensor probes of the monitoring electrode 201 and temperature sensor 202 directly contact the medium on both sides of the membrane. The sensor probes of the monitoring electrode 201 and temperature sensor 202 located outside the secondary membrane of the geomembrane contact the soil layer below the landfill. The sensor probes of the monitoring electrode 201 and temperature sensor 202 located between the secondary membrane and the main membrane of the geomembrane contact the bentonite waterproof blanket between the secondary membrane and the main membrane.

[0029] In this embodiment, the power supply 320 is a rechargeable power source, preferably a lithium battery. The power supply 320 has an AC charging port 321 and a solar charging port 322, which are electrically connected to the AC power grid and the solar panel, respectively. The AC charging port 321 is connected via a 220V to 12V adapter for charging, enabling combined solar and AC power charging. The local processing platform 300 also includes a power display screen 340 that shows the power level of the power source.

[0030] This embodiment also includes an online cloud platform 400 that is communicatively connected to the microcontroller 310, receiving and storing real-time data on the resistance value and temperature difference between the inside and outside of the landfill geomembrane. The online cloud platform 400 includes a cloud server for processing the real-time data on the resistance value and temperature difference between the inside and outside of the landfill geomembrane, including but not limited to data analysis, trend prediction, remote alarm, and visualization. All of the above data processing can be implemented using known software; this embodiment does not describe the specific data processing process. The online cloud platform 400 may also be equipped with a cloud storage device for storing the real-time data on the resistance value and temperature difference between the inside and outside of the landfill geomembrane, backing up the real-time monitoring data transmitted to the cloud. The online cloud platform 400 and the microcontroller 310 are connected via a 485 wired communication connection or a WiFi wireless communication connection. The online cloud platform can adopt a mature industrial IoT service platform, such as a cloud platform, which has its own cloud disk for data storage.

[0031] In addition, this embodiment also includes a local storage module 330 in the local processing platform 300. The local storage module 330 is communicatively connected to the microcontroller 310 and locally stores the resistance value between the inside and outside of the landfill geomembrane obtained from the voltage and current signals of the monitoring electrodes, as well as the temperature difference between the inside and outside of the landfill geomembrane detected by the temperature sensor, to ensure that data is not lost when the network is disconnected. In this embodiment, the microcontroller is an STM32F103VET6, which integrates an SPI Flash chip W25Q128JVSIQ as the local storage module.

[0032] In this embodiment, multiple user terminals 500 are connected to the online cloud platform 400. The user terminals can be mobile phones or computers connected to the online cloud platform 400. They are equipped with an alarm module to provide alarm reminders for changes in the resistance value and / or temperature difference between the inside and outside of the geomembrane in the landfill. If the measured resistance value between the inside and outside of the geomembrane is less than the alarm threshold and the temperature between the inside and outside of the geomembrane rises sharply, the online cloud platform 400 will issue an alarm and notify the user via telephone or SMS through the user terminal 500.

[0033] See also Figure 2 The real-time monitoring process for landfill leakage in this embodiment is as follows: When the geomembrane is damaged, the leachate, acting as a conductive medium, causes the intermembrane resistance to drop sharply from its normal value to <1MΩ. Simultaneously, leachate leakage triggers a sudden temperature change between the inside and outside of the membrane (temperature gradient exceeding the threshold, default >2℃ / min). On the membrane, monitoring electrodes 201 and temperature sensors 202 are placed between the primary and secondary geomembranes and on the outside of the secondary membrane, respectively, closely adhering to both sides of the secondary membrane. The signals collected by the monitoring electrodes 201 and temperature sensors 202 are transmitted in real-time to the microcontroller 310 for centralized processing. In the local processing platform, the microcontroller 310 filters the raw data from the monitoring electrodes 201 and temperature sensors 202 to eliminate noise interference and calculates the resistance value and the temperature difference between the inside and outside of the membrane. If the resistance value remains ≤0.9MΩ for 5 minutes and the temperature judgment conditions (temperature difference between inside and outside the membrane >5℃ or temperature change rate >2℃ / min) are met, a local leakage alarm is triggered, and the specific leakage location of the corresponding monitoring electrode and temperature sensor is reported. While the data from the local processing platform is transmitted to the local storage module 330 for on-site display or storage, it is simultaneously transmitted to the DTU terminal via RS485, and then encrypted and uploaded to the online cloud platform (400) via a 4G antenna. Users can monitor the leakage status in real time through the user terminal 500 on the online cloud platform, set alarm thresholds, and automatically trigger SMS / telephone alarms after a leakage event is detected. It also supports the export and management of historical data.

[0034] This embodiment's processing flow ensures that initial data screening and analysis are completed at the front end, reducing the computational burden on the cloud platform and guaranteeing the effective uploading of critical information. The online cloud platform 400 allows users to remotely monitor data such as resistance and temperature, as well as device status, in real time via the cloud platform. It can also handle more advanced data analysis, trend prediction, remote alarms, and visualization. It supports intelligent early warning and alarm functions for the user terminal; when the resistance value remains below 1MΩ for 5 minutes and the temperature rises sharply, it will automatically send an alarm via SMS or telephone. The online cloud platform 400's backend algorithm combines resistance mutations and temperature gradient parameters to reduce the false alarm rate. Furthermore, data is synchronously stored on the local hard drive and in the cloud for convenient historical querying and analysis. Authorized users are also allowed to remotely control device parameters through the user terminal 500.

[0035] In this document, the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer", "vertical", and "horizontal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the purpose of clarifying the technical solution and for the convenience of description, and therefore should not be construed as limiting the present utility model.

[0036] In this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0037] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A landfill leakage real-time monitoring system based on megohm resistivity method, characterized in that include: The membrane sensor (200) includes a monitoring electrode (201) and a temperature sensor (202) arranged in an array on both sides of the geomembrane in the landfill. A set of monitoring electrodes (201) and a set of temperature sensors (202) are arranged on the inside and outside of the geomembrane at the same location. The local processing platform (300) includes a power supply (320) and a microcontroller (310) that communicates with the sensors on the membrane. The power supply (320) is electrically connected to the monitoring electrodes (201) on both sides of the landfill geomembrane through the high voltage module of the microcontroller (310). The microcontroller (310) is also connected to the monitoring electrodes (201) and the temperature sensor (202) respectively. It receives the voltage and current signals through the monitoring electrodes to obtain the resistance value between the inside and outside of the landfill geomembrane and the temperature difference between the inside and outside of the landfill geomembrane detected by the temperature sensor. The online cloud platform (400) is connected to the microcontroller (310) to receive and store real-time data on the resistance value and temperature difference between the inside and outside of the geomembrane in the landfill. Several user terminals (500) are connected to the online cloud platform (400) for communication.

2. The landfill leakage real-time monitoring system based on megohm resistivity method according to claim 1, characterized in that: The landfill geomembrane includes a main geomembrane (101) and a secondary geomembrane (102) that are laid in an overlapping manner from top to bottom. The monitoring electrode (201) and temperature sensor (202) inside the membrane are arranged between the main geomembrane (101) and the secondary geomembrane (102), and the monitoring electrode (201) and temperature sensor (202) outside the membrane are arranged on the outside of the secondary geomembrane (102).

3. The landfill leakage real-time monitoring system based on megohm resistivity method according to claim 2, characterized in that: The monitoring electrode (201) and temperature sensor (202) are fixed to the landfill geomembrane by a sealing flange made of insulating material, and the sensor probes of the monitoring electrode (201) and temperature sensor (202) directly contact the medium on both sides of the membrane.

4. The landfill leakage real-time monitoring system based on megohm resistivity method according to claim 1, characterized in that: The power supply (320) is a rechargeable power supply with an AC charging port (321) and a solar charging port (322), which are electrically connected to the AC power grid and the solar panel, respectively, and are powered by a combination of solar and AC charging.

5. The landfill leakage real-time monitoring system based on megohm resistivity method according to claim 4, characterized in that: The local processing platform (300) also includes a power display screen (340) that displays the power level.

6. The landfill leakage real-time monitoring system based on megohm resistivity method according to claim 1, characterized in that: The local processing platform (300) also includes a local storage module (330), which is connected to the microcontroller (310) to locally store the resistance value between the inside and outside of the landfill geomembrane obtained from the voltage and current signals of the monitoring electrodes and the temperature difference between the inside and outside of the landfill geomembrane detected by the temperature sensor.

7. The landfill leakage real-time monitoring system based on megohm resistivity method according to claim 1, characterized in that: The online cloud platform (400) includes a cloud server for processing real-time data on the resistance value and temperature difference between the inside and outside of the landfill geomembrane, and a cloud storage for storing the real-time data on the resistance value and temperature difference between the inside and outside of the landfill geomembrane.

8. The landfill leakage real-time monitoring system based on megohm resistivity method according to claim 7, characterized in that: The online cloud platform (400) and the microcontroller (310) are connected via a 485 wired communication connection or a WiFi wireless communication connection.

9. The landfill leakage real-time monitoring system based on megohm resistivity method according to claim 1, characterized in that: The user terminal (500) is equipped with an alarm module to provide alarm reminders for changes in the resistance value and / or temperature difference between the inside and outside of the geomembrane in the landfill.

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