1
1
1
2
12
‐175%‐150%‐125%‐100%‐75%‐50%‐25%0%25%50%75%100%125%150%175%Relative difference for climate change
between incineration with energy recovery and composting
according to the degradation rate during composting>150%<‐ 1
50
%<‐150%incineration with
energy recovery
preferred to
compostingcomposting
preferred to
incineration with
energy recovery>150%<‐
150
%<‐150%incineration with
energy recovery
preferred to
compostingcomposting
preferred to
incineration with
energy recovery Study^ n°2 Study^ n°7
Study n°1 Study^ n°6Higher
degradation rateLower
degradation rateFigure 31 Influence of the degradation rate on the environmental assessment of composting and landfill regarding climate change
The comparison between cases 4[MUB1] and 4[MUB2] confirm the importance of this parameter because when
the degradation rate changes from 30% to 50%, the environmental contribution to climate change of landfill
increases by 83% and that of composting by 14% (See Table 59). The impact on landfill is greater since the
authors have assumed that the material (PLA-compound-PLA) is degraded into methane during the landfill
process, while no methane emissions occur during the composting process.
Table 59 Influence of the degradation rate on the performances of landfill and composting regarding the climate change potential in study no 4Case
Degradation
rate
Landfill Composting
4[MUB1] 30% 1209 ‐ 248
4[MUB2] 50% 3452 ‐ 213
Climate change potential
(kg CO2 eq/t)
In study no 2, a sensitivity analysis was conducted to check the influence of carbon sequestration on the
environmental performances of composting and landfill regarding climate change. It showed that the results were
extremely dependent on this parameter and that it could completely change the conclusions as shown in Table
- For example for PLA, while composting was the worst option when carbon sequestration was not taken into
account, it became the best option once a 30% degradation rate was assumed (i.e. 70% sequestrated).