Structural Health Monitoring of Large-Scale Geomembrane Floating Covers Using Solar Energy

Abstract

High-density polyphenylene geomembranes are utilized as large-scale floating covers in anaerobic water treatment plants for the purpose of collecting renewable biogas energy and preventing the emission of odorous by-products. During degradation, the accumulation of scum, the presence of biogas pockets and sewage can negatively impact the structural integrity of the covers and hinder degradation efficiency. Traditional methods are insufficient in identifying the substances under the covers. In this study, a thermography technique was developed and tested in lab-scale experiments using ambient weather information to inspect the geomembranes. The technique was then applied to a remote monitoring investigation of large-scale floating covers located at a sewage treatment plant. Long-term monitoring of two regions on the covers was conducted using a thermal camera, with ambient weather information recorded to help analyze temperature changes. The acquired thermal image sequences were analyzed, resulting in the creation of a segmented cover map indicating the profiles of substances. The results of the on-site thermal imaging field trials verify the effectiveness of the developed remote sensing thermography technique, which has the potential to assist in future asset maintenance, remove scum efficiently and enhance anaerobic degradation efficiency at sewage water treatment plants.