Table 22 Influence of the carbon sequestration on the environmental assessment of recycling regarding climate changeRecycling^ Landfill^
Case
Carbon
sequestration
Ranking of
alternative
Carbon
storage
Ranking of
alternative
1[PB] No + (^) No ++
2[NS] No +++ (^) Yes +
2[CC] No +++ (^) Yes +
2[MC] No +++ (^) Yes +
3[PS] No ++ (^) No +
3[EN] No ++ (^) No +
4[CC] Yes +++ (^) Yes +
4[MA] Yes +++ (^) Yes +
4[NS] Yes +++ (^) Yes ++
4[OP] Yes +++ (^) Yes +
4[PB] Yes +++ (^) Yes ++
4[TE] Yes +++ (^) Yes +
4[MP] Yes +++ (^) Yes +
5[PA] No ++ (^) No +
5[MC] No ++ (^) No +
Carbon storage is modelled in studies 2 and 4. However, the specifics of the modelling are not given, and
therefore it is difficult to assess the effect of this inclusion on the overall results. However, carbon storage is more
relevant for paper than for the organic fraction (i.e. food and garden waste). This is due to paper’s lower
degradation ratio which means that high amounts of carbon may remain stored during the climate change
assessment time frame of 100 years.
The issue of alternative use of forest/wood because of the recycling savings was addressed in only one study (no
- and was not assessed in any of the studies. This issue is quite controversial and a consensus has not yet been
reached yet by the international scientific community. However, the effect of this alternative use can be quite
high (Merrild et al. 2008).
Other parameters
There are some other assumptions that influence the results and that can potentially affect the classification of
the treatment options. First of all, the composition of the material in question, as well as the purity when
collected, are quite vital, as they determine all the resulting characteristics, such as heating values, recycling ratio
etc. Moreover, different types of paper are produced from differently processed pulp (e.g. using steam or
electricity) and therefore have different environmental burdens (or benefits when recycled). Studies 2 and 4 show
that different types of paper can produce different results. Especially in study no 4, where many different types of
paper are examined, the differences in the results are indicative of the different systems examined. However, as
many assumptions differ between studies, it is not possible to draw out specific conclusions for the different
materials. The energy balances for both processes involved in the treatment and avoided processes saved by
energy or material recovery are quite different as the study underlines and it is the energy budgets which are
considered mainly responsible for the variations on the results. Another parameter that depends on the material
and the technological assumptions is the loss rate in the case of recycling. Study no 4 assumes different rates for
different materials according to the condition of the paper fibres. The level of the benefits for each material
recycled is multiplied by the recycling ratio, reducing the negative contributions substantially in some cases.
3.2.4 Conclusion..............................................................................................................
Overall, the conclusions from this review can be summarised in two main axes. The first is a comparison of end-
of-life options and the second is the location of important factors influencing the results.
Generally, the quality of the selected LCAs was satisfactory, as full transparency and elaborate analysis of the
assumptions was a precondition for the short-listing. The systems under study were comprehensively described,
ensuring clarity and coherence for the results.