Environmental protection liner in a biodegradable waste pond: A case study

Abstract

High-density polyethylene (HDPE) geomembranes are often used as a liner in different applications, such as hazardous waste landfills, mining, water conservation, and waste ponds. The service exposure of materials causes thermal and oxidative degradation, changing the morphological structure of the polymer. This paper analyzed the final condition of an exhumed HDPE geomembrane sample that was 0.8 mm thick. The sample was collected from a biodegradable waste pond in the pond's slope, which was in contact with the waste and environmental conditions during the 15.17 years of field exposure. Physical and thermoanalytical evaluations of the sample were carried out. The analyses demonstrated that the brittle tensile behavior was observed by the low tensile elongation (259.24%) and the low-stress crack resistance (SCR) value (8.89 h). The high-density value (0.965 g cm−3) corroborates with the high crystallinity of the sample (57%). The standard oxidative induction time (Std. OIT) test result (6.94 min) demonstrated the resin's unprotection against oxidative degradation. Besides, the DMA results demonstrated an interaction of the impregnated material with the polymer. The final condition of the exhumed HDPE geomembrane analyzed can cause a rupture, generating an environmental impact on the site.