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
q
q
q
n 1
I I l,
n I l,
0 I l,
1
I l,
0 I l,
1
Eq. 1
1
n0
n1
For each impact l, the total impact Il is expressed as the sum of impacts caused by each end-of-life,
I
I l n l,
n , n being the life cycle number. The Il,0 are the impacts resulting from the virgin life of the
product, from the extraction of the raw materials to its discarding. Il,1 are the impacts resulting from the first
life of the used product, from its cradle (bottle waste collection) to its different graves.
Global Warming Potential (GWP 100), abiotic depletion and acidification have been selected among the
indicators: ozone depletion and photochemical oxidation are excluded due to the low emissions associated to
the processes considered. Toxicity and ecotoxicity have not been considered as well due to the important
uncertainty in the calculations for several reasons: the synergies between pollutants are not considered, LCI
are often incomplete and uncertain, and characterisation factors are lacking for many pollutants.
The resulting multi-objective problem is to find the allocation of bottles between valorisation paths that
minimizes the environmental impacts of bottle end-of-lives. It is solved using a genetic algorithm (Ouattara
et al., 2012), and the trade-off between environmental impacts is illustrated through Pareto curves (Fig. 3).
Figure 3. Triobjective optimisation results, in the case of multiple recycling loops (red point shows the best
compromise found with TOPSIS method).
A decision support tool involving a variant of the so-called TOPSIS method (Technique for Order Preference
by Similarity to Ideal Solution) then determines best compromises among the optimal solutions (Ren et
al., 2007).
3. Results
The model has been applied first to the case of France in 2010, with the dedicated values of decision variables
di (Fig. 1) given in the literature (ADEME, 2002; RDC-Environnement, 2010; Valorplast, 2011). When
considering multiple recycling for PET bottles, the best solution is to collect 87% bottles and to regenerate
all of them into bottles by mechanical recycling. In this case, abiotic depletion, acidification and GWP impacts
respectively decrease by 141, 72 and 61%.
We then applied the model to the Ile-de-France region with its current waste treatment industrial sites.
The PREDMA regulation is aiming at a 60% waste collection rate in 2014 and 75% in 2019. Results in Figure
4 show that infinite recycling loops reduce abiotic depletion, acidification and GWP respectively by 64.5,
65 and 65%; meanwhile a 75% collection rate leads to a decrease of abiotic depletion, acidification and
GWP respectively by 28.5, 25 and 115%.
283