LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

PARALLEL SESSION 3B: PACKAGING 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
Figure1. The PET bottles waste management system, di decision variables (% in weight)
In this study, r-PET regenerated mechanically into a bottle can be further recycled, while the other recycled
products (fibre, film, unsaturated polyester) can only be incinerated or landfilled. The fraction of the
initial M kg of bottle that is recycled into bottle grade PET is called λ. It is then integrated into a flow of
virgin PET and reprocessed into λM kg of bottle, which is submitted to the same recycling alternatives as in
its first life, since it is not distinguishable from the virgin flow of bottle. The environmental impacts consequent
to these successive end-of-lives are taken into account, until the ultimate graves. The life cycle of
packaging waste is considered to be short enough to ignore any temporal evolution of the processes and parameters.
The allocation of the flow of bottles is consequently the same for each end-of-life cycle. λ is therefore
constant in time and given by the material balance of the system. After n recycling trips, the amount of
PET recycled to bottles is given by λ n M. The valorisation paths could be then simplified as presented in Fig.
2.
Transportation steps are also considered with an average distance between Material Recycling Facility
and sorting plant (a value of 400 km is considered in the calculations, yet, the local situation may be very
different).
Figure2. An exhaustive LCA: the cradle-to-grave approach
The environmental impacts are based on the calculation of the impacts involved in each elementary process
with Simapro LCA software tool, using the CML impact assessment method. The model also takes into
account the fraction of PET regenerated into bottles that can be further recycled. A non-linear model for the
bottle waste collection stage is also considered; reflecting that the more diffuse the flow of bottles is, the
more difficult it is to collect and consequently, the more environmentally impacting.
Finally, the global impacts are the cumulative impacts corresponding to each “end-of-life”, as expressed
in Eq. 1:
282
Intermediate
product 1
Intermediate
product 2
Product X
Recycled
products
Recycled
products
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