Long-term performance of textured HDPE geomembranes in municipal solid waste landfills

The effect of blown-film co-extrusion texturing (using entrained nitrogen gas) on the long-term performance of high-density polyethylene geomembranes (GMBs) immersed in synthetic municipal solid waste leachate is examined over an approximately 8-year period. Antioxidant depletion of the textured part is shown to be much faster than that of the smooth edge. Likewise, the degradation in the tensile break properties at 85 degrees C is faster for the textured part than for the smooth-edge portion and smooth equivalent. The updated estimates for antioxidant depletion time based on data at four different temperatures (40, 55, 75, and 85 degrees C) over 98 months of data collection are compared with predictions based on 34 months of data, and the implications are discussed. Nominal failure was reached at 75 degrees C, and this combined with data at 85 degrees C allows prediction of the time between depletion of standard oxidative induction time and nominal failure at lower temperatures. The effect of salt concentration in incubation fluid on the time to degradation is examined. Finally, the paper comments on the uses of textured versus smooth GMB.