Durability of two bituminous geomembranes (BGMs) with different thicknesses in MSW synthetic leachate

The effect of thickness (4.8 and 4.1 mm) on the degradation of two bituminous geomembranes (BGMs), when immersed in a synthetic leachate is investigated over a period of 33 months. Based on the data collected at four different temperatures (20, 40, 55, 70 °C), it is shown that the 4.1 mm has slightly faster degradation than the 4.8 mm thick BGM. Due to the reduced conditions of the examined leachate, the degradation in the chemical and rheological properties of the bitumen coat was relatively lower than in air and water immersion. However, the presence of a surfactant in the leachate increased the degradation of the polymeric back film and the reinforcement layer responsible for the mechanical properties of the BGM. The time to nominal failure of the two BGMs is predicted at a typical range of landfill liner temperatures using Arrhenius modelling. The predictions at temperatures >20 °C suggest that the examined BGMs may not be suitable for the containment of solid wastes containing surfactants due to the fast degradation in their mechanical properties.