Low-cost portable sensor toolbox for methane emissions quantification in landfills

Landfills are among the main anthropogenic sources of methane (CH4), a greenhouse gas with a global warming potential significantly higher than that of carbon dioxide (CO2). Monitoring fugitive emissions of methane from landfill surface is a crucial challenge: conventional techniques, although accurate, are expensive, cumbersome and unsuitable for widespread or repeated measurements over time. The European ESCAPE project addresses this critical issue by developing a portable toolbox equipped with low-cost sensors for detecting and quantifying methane emissions in landfills. The approach involves selecting and combining commercial sensors (e.g., MOX, NDIR) and coupling them with suitable machine learning algorithms to provide accurate quantification by compensating for environmental interferents such as humidity and other gases (e.g., CO2 and other VOCs). After a preliminary testing phase for sensor selection, a portable toolbox was realized and then tested and calibrated in the lab with different gases at different concentrations and humidity levels by means of a dedicated gas mixing system. Moreover, a first field survey was carried out to test hardware and software functionality in real-world conditions and provide data for validation of the calibration model. Initial results confirm the effectiveness of the toolbox for rapid field investigations and identification and quantification of emission hotspots with reduced costs and complexity, thus proving that it could represent an innovative tool to support the operational management of landfills and emission mitigation strategies