Landfilllogger

Description

The landfill logger is designed to monitor the concentrations of CH₄ and CO₂ under buildings or in the soil gas phase (in the unsaturated zone) to assess the risk of explosion and suffocation. Additionally, the loggers measure soil gas temperature, atmospheric pressure, and the vacuum necessary to extract soil gas.

The logger operates by pumping landfill gas from the sampling point, which can be a tube (monitoring point) installed under a building, a soil gas sampling point in the unsaturated zone, or a monitoring well. The purge time for tubes and other installations can be adjusted depending on the type of installation.

DMR has 11 landfill loggers available for rent for various applications.

As the sensors in the loggers are relatively power-consuming, the loggers have been designed to shut down completely between each measurement and turn on at a defined frequency. After starting up, the loggers warm the sensors and purge the system with gas from the sampling point. All these parameters can be set to fit the installation point with help from DMR experts, and the operational parameters can also be changed remotely via the DMR cloud platform during tests. The CO₂ sensor has a measuring range of 0.1-22% on all loggers. We have two loggers equipped with CH₄ sensors ranging from 1-100 vol% and nine loggers with CH₄ sensors ranging from 0-5 vol%.

The landfill loggers have two modes of operation: “constant frequency mode” and “intelligent sampling mode.”

In “constant frequency mode,” the logger measures all parameters (CH₄, CO₂, atmospheric pressure, and soil gas temperature/humidity/extraction vacuum) at each point. Typically, the logger can run for about 18-20 days with a frequency of 15 minutes.

The “intelligent sampling mode” is designed to measure atmospheric pressure at a high frequency (e.g., every 15 minutes) and the remaining parameters at a relatively low frequency (e.g., every 4 hours). When the atmospheric pressure suddenly drops at a rate (hPa/hour) above a defined threshold, the logger begins to log all parameters at the high frequency used for the pressure sensor. This means that during low-risk periods, we save a lot of battery while still getting some measurements, and during the most interesting periods, we get higher resolution data. Depending on the stability of the weather conditions, this will increase the battery life of the loggers and save costs for battery replacement.

As shown in the images below, the loggers can be installed in both a closed loop system where the gas is returned to a monitoring will via an innovative double tube installation, and a simple gas extraction installation, where the extracted gas is exhausted to the surroundings after measurement in the logger.

Contact our experts for more information about application of the loggers, rental prices etc.