Life cycle assessment of polylactic acid and polyethylene terephthalate bottles for drinking water



The biodegradable plastics were introduced in the 1980s to detect possible renewable feedstock to produce nonpetroleum-based plastics as well as to reduce the environmental problems due to the increase of landfill volume. Furthermore, the biodegradable plastics have been used to reduce the environmental impact (in terms of energy requirement from nonrenewable resources and CO2 gas emissions) derived from production, utilization, and disposal of petroleum-based plastics, like polyethylene terephthalate (PET). To this end, in the last years, different typologies of bioplastics were introduced (both biodegradable plastics and plastics made from renewable resources) like Mater-Bi (made from starch), poly-3-hydroxybuyrate, polycaprolactone, and polylactic acid (PLA).

Nowadays, the most important tool to evaluate the environmental impact of a bioplastic and/or of a petroleum-based plastic (conventional plastic) is the life cycle assessment (LCA) that determines the overall impact of a plastic on the environment by defining and analyzing several impact indices directly related to production, utilization, and disposal of the considered plastics.

In this work, the LCA (cradle to grave) of PLA bottles for drinking water was developed and compared to the LCA of PET bottles for the same use.

The obtained results highlighted that the true advantage of the PLA bottles with respect to the PET bottles arises from the use of renewable resources, but this benefit is paid in environmental terms due to the higher impact on human health and ecosystem quality (due to the use of pesticides, consumption of land, and consumption of water for the production of raw materials). © 2010 American Institute of Chemical Engineers Environ Prog, 2011