Monitoring of biogas emissions from an urban landfill by means of close-range aerial infrared thermography

Monitoring waste disposal sites is important to check that the produced biogas, potentially explosive and environmentally significant, is properly collected by the biogas extraction system of the landfill site and to evaluate the residual biogas flow escaping from the upper surface of the landfill. As the biogas migrates to the surface, the soil through which it flows is expected to reach a higher temperature than the surrounding environment; thus, measuring the thermal footprint of the landfill soil surface could allow the detection of biogas leakages and spots suitable for gas extraction. Infrared thermography is an innovative diagnostic tool able to detect thermal anomalies on the landfill surface. If the infrared camera is installed on an unmanned aerial vehicle, thermal anomalies can be identified with a good resolution over a large region. A simple procedure to deduce the biogas flow rate emerging from the soil into the atmosphere, based on infrared thermography measurements, is presented. The approach has been applied to a case study concerning a large landfill located in Genoa, northern Italy. Aerial infrared photographs taken during different days and seasons showed the presence of thermal anomalies over regions along the peripheral boundary of the landfill still not interested in biogas extraction.