Application of terrestrial thermography to the detection of waste-disposal sites

Abstract

The experiment presented here concerns the application of terrestrial thermography to the detection of potential anomalies in waste-disposal sites, defined differently according to their degree of waste stabilization and pollution. A thermal camera, operating in the middle infrared (3.5–5.6 μm) region, was used to test a methodology for identifying different waste sites, by means of their thermal contrast. A sequence of six data sets concerning various target types was taken during a complete descending thermal diurnal cycle. Additional meteorological and radiometric data sets were collected during surveys for the calibration of thermographies and computation of emissivity values. Good thermal differentiation was observed between the consolidated solid waste and the waste sections where processes of methane conversion are active, and between water surfaces with acid slimes and the uncontaminated outcropping water table. The best contrasts were observed during predawn conditions, when uniformities of air and ground temperature were high and the influence of solar charge was negligible. A constant 2 K temperature difference was observed as a surficial anomaly between differently consolidated waste sections and a 6 K temperature as a maximum difference outlining waters affected by wasting agents. The experiment, carried out at the waste disposal site of Gerenzano (Varese), Italy, verified the feasibility of using aerial thermography in the future and of extending the results achieved to other sites under similar conditions.