Environmental evaluation of non-alcoholic single-serve PET beverage bottles in the state of California using life cycle assessment and system dynamics.

摘要

An integrated environmental evaluation of non-alcoholic single-serve PET beverage bottles was conducted using life cycle assessment (LCA) and system dynamics. The life cycle of PET bottles was divided into 4 main phases: upstream, downstream, transportation and environmental benefit. The upstream phase included the production of PET resin, the manufacture of the PET bottles, the process of beverage filling and the production of secondary packaging. The downstream phase depicted the material recovery process of post-consumer PET bottles (PCB), recycling and landfill. The transportation phase was composed of the transportation during the PET bottle delivery and the PCB collection. The environmental benefit phase included the energy recovery from incineration, and the benefits from two different recycling routes, open loop and closed loop recycling.;First, an LCA model of PET bottles in the state of California was developed. The contribution analysis showed that most of the life cycle impacts were contributed by the production of the PET bottles. Moreover, sensitivity analysis was performed to evaluate the effect of the increase of PET recycled resin in the system by reducing either waste during PCB collection or yield loss in the recycling. The results implied that larger potential environmental benefit could be achieved by increasing yield efficiency in the recycling process than by improving the PCB collection system.;Secondly, a meta-analysis was performed to review the LCA literature on the PET bottle system using a harmonization process and statistical assessment. The goals were to evaluate the variation of the environmental impact in each life cycle stage of the PET bottle system, and to identify the source of variation by using global warming potential (GWP) and energy consumption (EC) impact indicators. Based on the statistical assessment results, the largest contribution to GWP and EC indicators was found from bottle grade PET resin production. The largest variation of GWP and EC indicators was for incineration of plastic waste due to a large variation in electricity efficiency for energy recovery from the incineration facility. This implied that the environmental performance of the PET bottle could be improved by optimizing the electricity recovery efficiency.;Lastly, a system dynamics and LCA approach was preliminarily employed to conduct a dynamic environmental assessment of the GWP of PET bottles in the state of California. The goals were to conduct a contribution analysis of the historical LCA of the PET beverage bottle system and to evaluate the impact of recycled PET (RPET) content and crude oil price over time on the PET beverage bottle in terms of CO2 tax (;Overall, this dissertation presented a methodology to construct a dynamic LCA model of PET bottles in California and the U.S., and can be used as a model to inform future studies of packaging systems.