A life cycle assessment of the closed-loop recycling and thermal recovery of post-consumer PET

Waste polyethylene terephthalate (PET) bottles collected by source-segregation recycling schemes can be treated by mechanical and chemical means to remove any contaminants. The cleaned PET can then be melted and formed into pellets with the same physical properties as virgin PET. Full-scale trials have shown that this reprocessed material can be used with virgin PET to make new bottles. An alternative recovery option is to collect the waste PET with the non-recyclable waste and burn it in an energy-from-waste plant. A life cycle inventory was produced for these two recovery options to compare the atmospheric emissions of key pollutants and the overall environmental impacts. The recycling option resulted in an overall reduction in the emission of each key pollutant and in the overall environmental impact. This was due to the reduction in emissions from displacing virgin PET. The energy-from-waste route also leads to a reduction in the emissions of several of the pollutants, depending on the assumptions made about the thermal efficiency of the process and the pollutants generated by burning the PET.