Life cycle assessment of different reuse percentages for glass beer bottles

Life cycle assessment (LCA) is increasingly becoming an important tool for ecological evaluation of products or processes. In this study the environmental impacts associated with the returnable and the non-returnable glass beer bottles were assessed in order to compare different reuse percentages. The inventory analysis is performed with data obtained from two Portuguese companies (a glass bottles producer and a brewery) and completed with the BUWAL database. It includes all operations associated with the bottles' manufacture, the brewery and the wastewater treatment plant. The environmental impact assessment considers both the potential ecological and ecotoxicological effects of the emissions. The environmental impact categories included and discussed in this study are the contribution to ecological and human health, global warming, stratospheric ozone depletion, acidification, eutrophication and photochemical ozone creation. The first category is divided into three subcategories that are human toxicity, critical air volume and critical water volume. This study was performed for several reuse percentages and returnable bottle cycles, and is comprised of a sensitivity analysis. The general output is that the relative importance of the impacts associated with the use of returnable and/or non-returnable bottles depends on the number of cycles performed by the returnable bottles. According to the impact index defined in this study, the most significant impacts are the eutrophication and the final solid wastes generated, and the least significant impact is the ozone depletion.