3.2.3 Detailed comparison between the various treatment options
Climate change
Figure 4 depicts the relative preferability of one treatment option over another. First recycling is compared to the
other options and then incineration.
An overall conclusion would be that landfill is generally the worst option regarding climate change. The results for
incineration and recycling are inconsistent, as many studies disagree about which is preferable. Three studies
support incineration and only two recycling, but many more cases are included in the latter analyses.
When comparing recycling to other options, it is quite clear that landfill is the worst. Indeed, the majority of cases
in this comparison are gathered in the far upper part of the diagram, which should be interpreted as a large
difference in the global warming contribution (relative preference of more than 150%). Only one case classifies
landfill as a better option, but when the specific conditions of the studies are examined the explanation becomes
clear: in that study (Study no 1) the simulated landfill is assumed to apply state-of-the-art technologies such as
reverse osmosis, flaring of uncontrolled gas and others that lead to a relative high landfill gas collection
efficiency. This configuration, combined with the fact that the virgin paper is assumed to be produced in Sweden
(where the electricity mix is less carbon intensive than in many other countries) results in the relative preference
of landfill over other options. This case is a perfect example of how the assumptions and parameters assumed in
the LCA can have a drastic effect on the final outcome.
On the other hand, when recycling is compared to incineration, a more balanced image appears. A case-by-case
analysis shows that recycling might be preferable since there are more cases on the positive side of Figure 4. An
interesting observation is that the selected studies are consistent regarding the included cases: all cases within
the same study agree on which is the best alternative. The result is that there are three studies in favour of
incineration and two in favour of recycling. Of the studies favouring incineration:
Study no1, as explained above, is configured in such a way that the results can be easily explained.
Study no 3 has a French context but as the study does not focus specifically on end-of-life, so the
result favouring incineration cannot be investigated further.
Study no 5 also takes place in a less carbon-intensive environment in terms of electricity mix.An important observation is that all three studies that classify incineration as preferable base their geographical
scope assumptions in countries with a high share of CO 2 free energy mixes (France, Sweden). In all these cases,
the benefits from choosing incineration are higher which can seem contradictory since the energy credits are
lower than when the energy mix relies on fossil fuels. An explanation for this preference for incineration could be
that the balance between the energy used directly in recycling processes versus the energy saved by avoiding the
production of primary material is not very advantageous for recycling. A disaggregation of the processes and
corresponding energy balances involved in each treatment alternative (e.g. energy used directly in recycling
processes versus energy saved by recycling processes) could give a better understanding of the situation, but this
would require the examination of the LCA modelling used as well as the inventory data which are not published in
the studies. In each study only aggregated results are presented, namely the final sum of the recycling route
including all direct and indirect processes, as well as transport and other energy.
Figure 5 compares incineration to the other end-of-life alternatives. The comparison to landfill is clearly in favour
of incineration except for two cases where landfill appears slightly superior. The two cases (newspaper and
phonebooks cases included in study no 4) that favour landfill refer to two materials with similar waste
characteristics (according to the model), but their differentiation from the other materials is not explained. The
degradation rate, which is not mentioned in the study, might be responsible for the better performance of landfill
in these cases. This lack of transparency is among the weaknesses of the study.