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HDPE Geomembranes for Environmental Protection: Two Case Studies

by | Nov 12, 2021 | Application study

Introduction to HDPE Damliner / Geomembrane

A geomembrane is a product of the geosynthetics family used as a liner in the environmental protection system. This polymeric product can be manufactured by the industry in different polymers and it is installed in the field. The high-density polyethylene (HDPE) geomembrane is the most used type of geomembrane in the world, especially for landfills and waste liquid ponds. The high chemical and mechanical resistance of HDPE associated with a low permeability coefficient and low cost of production are the advantages of this product.

For landfill liner applications, the HDPE geomembrane can be exposed to aging mechanisms such as thermal and chemical degradations. Moreover, for slopes, in the installation time, UV radiation exposition occurs. For leachate ponds and liquid waste treatment applications, the product can be exposed to UV radiation and high temperatures, as well as the chemical and biological contact. This set of aging mechanisms can degrade the geomembrane and decrease the material’s durability.

The synergic effects of aging mechanisms can significantly reduce the lifetime of the product. A package of additives is incorporated into the resin to protect the polymer and guarantee the long-term service life.

In general, carbon black (2–3%) is incorporated into the polymeric resin as UV protection and antioxidants and thermalstabilizers (0.5–1.0%) as thermal and oxidative protection.

Islam and Rowe carried out a study with high-density polyethylene geomembranes with nominal thicknesses of 1.5, 2.0 and 2.5 mm immersed in synthetic leachate at four temperatures (22, 55, 70 and 85 ◦C). The authors used the standard oxidative induction time (OIT) test to evaluate the antioxidant depletion of the samples. They understood which samples with thicker thicknesses demand more time to consume the additives. They concluded that the thicker geomembranes have longer service lives. Research conducted by Rowe et al. studied an HDPE geomembrane sample (1.5 mm of thickness) in contact with four synthetic leachates with different combinations of volatile fatty acids, inorganic nutrients, trace metal solution and surfactant at four temperatures (the lowest was 22 ◦C and the highest was 85 ◦C). The Arrhenius modeling was used to analyze the antioxidant depletion of the geomembrane. The four leachates examined were similar in terms of the antioxidant depletion rate, but the faster depletion occurred in acidic and basic leachates.

Download the full article on HDPE Geomembranes for Environmental Protection – 2 case studies below:

HDPE Damliner-Geomembrane Case study – sustainability-12-08682